Science.gov

Sample records for core puchezh-katunki impact

  1. Diaplectic transformation of minerals: Vorotilov drill core, Puchezh-Katunki impact crater, Russia

    NASA Technical Reports Server (NTRS)

    Feldman, V. I.

    1992-01-01

    The Vorotilov core was drilled in the central uplift of the Puchezh-Katunki astrobleme to a depth of 5.1 km. Impactites are revealed in the rocks of the core beginning from a depth of 366 m: suevites (66 m), allogenic breccias (112 m), and autogenic breccias (deeper than 544 m). These rocks are represented by shocked-metamorphic gneisses, schists, amphibolites of Archean age, and magmatic rocks (dolerites, olivines, and peridotites) that lie between them.

  2. Geomechanical models of impact cratering: Puchezh-Katunki structure

    NASA Technical Reports Server (NTRS)

    Ivanov, B. A.

    1992-01-01

    Impact cratering is a complex natural phenomenon that involves various physical and mechanical processes. Simulating these processes may be improved using the data obtained during the deep drilling at the central mound of the Puchezh-Katunki impact structure. A research deep drillhole (named Vorotilovskaya) has been drilled in the Puchezh-Katunki impact structure (European Russia, 57 deg 06 min N, 43 deg 35 min E). The age of the structure is estimated at about 180 to 200 m.y. The initial rim crater diameter is estimated at about 40 km. The central uplift is composed of large blocks of crystalline basement rocks. Preliminary study of the core shows that crystalline rocks are shock metamorphosed by shock pressure from 45 GPa near the surface to 15-20 GPa at a depth of about 5 km. The drill core allows the possibility of investigating many previously poorly studied cratering processes in the central part of the impact structure. As a first step one can use the estimates of energy for the homogeneous rock target. The diameter of the crater rim may be estimated as 40 km. The models elaborated earlier show that such a crater may be formed after collapse of a transient cavity with a radius of 10 km. The most probable range of impact velocities from 11.2 to 30 km/s may be inferred for the asteroidal impactor. For the density of a projectile of 2 g/cu cm the energy of the impact is estimated as 1E28 to 3E28 erg. In the case of vertical impact, the diameter of an asteroidal projectile is from 1.5 to 3 km for the velocity range from 11 to 30 km/s. For the most probable impact angle of 45 deg, the estimated diameter of an asteroid is slightly larger: from 2 to 4 km. Numerical simulation of the transient crater collapse has been done using several models of rock rheology during collapse. Results show that the column at the final position beneath the central mound is about 5 km in length. This value is close to the shock-pressure decay observed along the drill core. Further

  3. Core merging and stratification following giant impact

    NASA Astrophysics Data System (ADS)

    Landeau, Maylis; Olson, Peter; Deguen, Renaud; Hirsh, Benjamin H.

    2016-10-01

    A stratified layer below the core-mantle boundary has long been suspected on the basis of geomagnetic and seismic observations. It has been suggested that the outermost core has a stratified layer about 100 km thick that could be due to the diffusion of light elements. Recent seismological evidence, however, supports a layer exceeding 300 km in thickness of enigmatic origin. Here we show from turbulent mixing experiments that merging between projectile and planetary core following a giant impact can lead to a stratified layer at the top of the core. Scaling relationships between post-impact core structure and projectile properties suggest that merging between Earth's protocore and a projectile core that is enriched in light elements and 20 times less massive can produce the thick stratification inferred from seismic data. Our experiments favour Moon-forming impact scenarios involving a projectile smaller than the proto-Earth and suggest that entrainment of mantle silicates into the protocore led to metal-silicate equilibration under extreme pressure-temperature conditions. We conclude that the thick stratified layer detected at the top of Earth's core can be explained as a vestige of the Moon-forming giant impact during the late stages of planetary accretion.

  4. Coring the Chesapeake Bay impact crater

    USGS Publications Warehouse

    Poag, C.W.

    2004-01-01

    In July 1983, the shipboard scientists of Deep Sea Drilling Project Leg 95 found an unexpected bonus in a core taken 150 kilometers east of Atlantic City, N.J. At Site 612, the scientists recovered a 10-centimeter-thick layer of late Eocene debris ejected from an impact about 36 million years ago. Microfossils and argon isotope ratios from the same layer reveal that the ejecta were part of a broad North American impact debris field, previously known primarily from the Gulf of Mexico and Caribbean Sea. Since that serendipitous beginning, years of seismic reflection profiling, gravity measurements and core drilling have confirmed the source of that strewn field - the Chesapeake Bay impact crater, the largest structure of its kind in the United States, and the sixth-largest impact crater on Earth.

  5. Core excitation of Li by electron impact

    SciTech Connect

    Tiwary, S.N.

    1985-07-01

    Cross sections for the excitation of a core electron, which leads to autoionization, in lithium (Li) atomic system by electron impact have been calculated with use of the single-configuration Hartree-Fock wave function within the asymptotic Green's-function approximation (AGFA) in the low-bombarding-energy region. Comparison is made with available results. Our investigation demonstrates that the AGFA supports the R-matrix as well as the distorted-wave Born-approximation behavior.

  6. Giant impacts, core stratification, and failure of the Martian dynamo

    NASA Astrophysics Data System (ADS)

    Arkani-Hamed, Jafar; Olson, Peter

    2010-07-01

    The close timing of the giant impacts and the cessation of the core dynamo of Mars at around 4 Ga suggest a possible causal relationship between these two events. We study the shock heating of the Martian interior caused by the impact that created Utopia basin, the largest of the 20 giant impact basins formed on Mars around 4 Ga. Using empirical scaling laws connecting the diameters of the basin and the projectile, we calculate the shock pressure distribution in Mars on the basis of Pierazzo et al.'s (1997) formula, which is then used to estimate the impact-induced temperature increase in the Martian mantle and core, adopting the “ordinary” and “foundering” shock heating mechanisms proposed by Watters et al. (2009) and impact velocities of 10 and 15 km/s. It is shown that the reduction of the heat flux out of the core due to impact heating of the overlying mantle is on the order of 0.03%-0.3% of the preimpact heat flux of the core (15 mW/m2), indicating that the impact heating of the mantle has insignificant effect on the thermal convection of the core. However, the shock waves that penetrate into the core directly and differentially heat the core in only a few minutes, which causes stable thermal stratification of the core within about a few years and diminishes the core convection and the thermally driven core dynamo within a few thousand years. Exhaustion of the impact heat and removal of the stratification is necessary to reestablish a superadiabatic temperature gradient and reactivate convection in the core. As the impact heat becomes concentrated in the upper parts of the core, the stratified part of the core first cools by conduction to the mantle and then later with a contribution from penetrative convection below the core-mantle boundary and by conduction into the deeper parts of the core. Depending on the impact velocity and the shock heating mechanisms, tens of millions of years may be needed to fully exhaust the core heat to the mantle, during

  7. Consequences of large impacts on Enceladus' core shape

    NASA Astrophysics Data System (ADS)

    Monteux, J.; Collins, G. S.; Tobie, G.; Choblet, G.

    2016-01-01

    The intense activity on Enceladus suggests a differentiated interior consisting of a rocky core, an internal ocean and an icy mantle. However, topography and gravity data suggests large heterogeneity in the interior, possibly including significant core topography. In the present study, we investigated the consequences of collisions with large impactors on the core shape. We performed impact simulations using the code iSALE2D considering large differentiated impactors with radius ranging between 25 and 100 km and impact velocities ranging between 0.24 and 2.4 km/s. Our simulations showed that the main controlling parameters for the post-impact shape of Enceladus' rock core are the impactor radius and velocity and to a lesser extent the presence of an internal water ocean and the porosity and strength of the rock core. For low energy impacts, the impactors do not pass completely through the icy mantle. Subsequent sinking and spreading of the impactor rock core lead to a positive core topographic anomaly. For moderately energetic impacts, the impactors completely penetrate through the icy mantle, inducing a negative core topography surrounded by a positive anomaly of smaller amplitude. The depth and lateral extent of the excavated area is mostly determined by the impactor radius and velocity. For highly energetic impacts, the rocky core is strongly deformed, and the full body is likely to be disrupted. Explaining the long-wavelength irregular shape of Enceladus' core by impacts would imply multiple low velocity (<2.4 km/s) collisions with deca-kilometric differentiated impactors, which is possible only after the LHB period.

  8. Laboratory Experiments on Core Merging and Stratification After Giant Impacts

    NASA Astrophysics Data System (ADS)

    Landeau, M.; Olson, P.; Deguen, R.; Hirsh, B.

    2015-12-01

    The fluid dynamics of core merging after giant impacts in the late stages of accretion provides constraints on metal-silicate equilibration, core stratification, and early magnetic field generation. The energy released during giant impacts, such as those thought to have formed Earth's Moon and the crustal dichotomy on Mars, likely resulted in melting of the impactor and much or all of the protoplanet's mantle. Under these conditions, the liquid core of the impactor migrates through a fully-liquid magma ocean, and merges with the protoplanet's core. Unlike the laminar flow in numerical simulations, liquid impact experiments can produce turbulence, as expected during core formation. We present experiments on liquid blobs of variable density released into another liquid consisting of two immiscible layers, representing the magma ocean and protocore, respectively. The released liquid is denser than the upper layer, immiscible in the upper layer, and miscible in the lower layer. With a shallow upper layer, the relevant regime for giant impacts, a turbulent cloud of released and upper liquids penetrates into the lower layer, collapses and spreads along the interface between the upper and lower layers. This behavior contrasts with the laminar core merging observed in impact simulations or the classical iron rain scenario, and suggests that metal-silicate chemical equilibration extends inside the protocore. Experimental scalings for low-density releases predict that compositional stratification of the core is likely in the aftermath of planet formation, and the stratified layer detected by seismology at the top of Earth's core is compatible with a moon-forming impact. By implication, the early core dynamo had to overcome compositional stratification to initiate.

  9. Geochemical Comparison of Four Cores from the Manson Impact Structure

    NASA Technical Reports Server (NTRS)

    Korotev, Randy L.; Rockow, Kaylynn M.; Jolliff, Bradley L.; Haskin, Larry A.; McCarville, Peter; Crossey, Laura J.

    1996-01-01

    Concentrations of 33 elements were determined in relatively unaltered, matrix-rich samples of impact breccia at approximately 3-m-depth intervals in the M-1 core from the Manson impact structure, Iowa. In addition, 46 matrix-rich samples from visibly altered regions of the M-7, M-8, and M-10 cores were studied, along with 42 small clasts from all four cores. Major element compositions were determined for a subset of impact breccias from the M-1 core, including matrix-rich impact-melt breccia. Major- and trace-element compositions were also determined for a suite of likely target rocks. In the M-1 core, different breccia units identified from lithologic examination of cores are compositionally distinct. There is a sharp compositional discontinuity at the boundary between the Keweenawan-shale-clast breccia and the underlying unit of impact-melt breccia (IMB) for most elements, suggesting minimal physical mixing between the two units during emplacement. Samples from the 40-m-thick IMB (M-1) are all similar to each other in composition, although there are slight increases in concentration with depth for those elements that have high concentrations in the underlying fragmental-matrix suevite breccia (SB) (e.g., Na, Ca, Fe, Sc), presumably as a result of greater clast proportions at the bottom margin of the unit of impact-melt breccia. The high degree of compositional similarity we observe in the impact-melt breccias supports the interpretation that the matrix of this unit represents impact melt. That our analyses show such compositional similarity results in part from our technique for sampling these breccias: for each sample we analyzed a few small fragments (total mass: approximately 200 mg) selected to be relatively free of large clasts and visible signs of alteration instead of subsamples of powders prepared from a large mass of breccia. The mean composition of the matrix-rich part of impact-melt breccia from the M-1 core can be modeled as a mixture of approximately

  10. Hypervelocity Impact Evaluation of Metal Foam Core Sandwich Structures

    NASA Technical Reports Server (NTRS)

    Yasensky, John; Christiansen, Eric L.

    2007-01-01

    A series of hypervelocity impact (HVI) tests were conducted by the NASA Johnson Space Center (JSC) Hypervelocity Impact Technology Facility (HITF) [1], building 267 (Houston, Texas) between January 2003 and December 2005 to test the HVI performance of metal foams, as compared to the metal honeycomb panels currently in service. The HITF testing was conducted at the NASA JSC White Sands Testing Facility (WSTF) at Las Cruces, New Mexico. Eric L. Christiansen, Ph.D., and NASA Lead for Micro-Meteoroid Orbital Debris (MMOD) Protection requested these hypervelocity impact tests as part of shielding research conducted for the JSC Center Director Discretionary Fund (CDDF) project. The structure tested is a metal foam sandwich structure; a metal foam core between two metal facesheets. Aluminum and Titanium metals were tested for foam sandwich and honeycomb sandwich structures. Aluminum honeycomb core material is currently used in Orbiter Vehicle (OV) radiator panels and in other places in space structures. It has many desirable characteristics and performs well by many measures, especially when normalized by density. Aluminum honeycomb does not perform well in Hypervelocity Impact (HVI) Testing. This is a concern, as honeycomb panels are often exposed to space environments, and take on the role of Micrometeoroid / Orbital Debris (MMOD) shielding. Therefore, information on possible replacement core materials which perform adequately in all necessary functions of the material would be useful. In this report, HVI data is gathered for these two core materials in certain configurations and compared to gain understanding of the metal foam HVI performance.

  11. Research core drilling in the Manson impact structure, Iowa

    NASA Technical Reports Server (NTRS)

    Anderson, R. R.; Hartung, J. B.; Roddy, D. J.; Shoemaker, E. M.

    1992-01-01

    The Manson impact structure (MIS) has a diameter of 35 km and is the largest confirmed impact structure in the United States. The MIS has yielded a Ar-40/Ar-39 age of 65.7 Ma on microcline from its central peak, an age that is indistinguishable from the age of the Cretaceous-Tertiary boundary. In the summer of 1991 the Iowa Geological Survey Bureau and U.S. Geological Survey initiated a research core drilling project on the MIS. The first core was beneath 55 m of glacial drift. The core penetrated a 6-m layered sequence of shale and siltstone and 42 m of Cretaceous shale-dominated sedimentary clast breccia. Below this breccia, the core encountered two crystalline rock clast breccia units. The upper unit is 53 m thick, with a glassy matrix displaying various degrees of devitrification. The upper half of this unit is dominated by the glassy matrix, with shock-deformed mineral grains (especially quartz) the most common clast. The glassy-matrix unit grades downward into the basal unit in the core, a crystalline rock breccia with a sandy matrix, the matrix dominated by igneous and metamorphic rock fragments or disaggregated grains from those rocks. The unit is about 45 m thick, and grains display abundant shock deformation features. Preliminary interpretations suggest that the crystalline rock breccias are the transient crater floor, lifted up with the central peak. The sedimentary clast breccia probably represents a postimpact debris flow from the crater rim, and the uppermost layered unit probably represents a large block associated with the flow. The second core (M-2) was drilled near the center of the crater moat in an area where an early crater model suggested the presence of postimpact lake sediments. The core encountered 39 m of sedimentary clast breccia, similar to that in the M-1 core. Beneath the breccia, 120 m of poorly consolidated, mildly deformed, and sheared siltstone, shale, and sandstone was encountered. The basal unit in the core was another sequence

  12. Impact of network sharing in multi-core architectures.

    SciTech Connect

    Narayanaswamy, G.; Balaji, P.; Feng, W.; Mathematics and Computer Science; Virginia Tech

    2008-01-01

    As commodity components continue to dominate the realm of high-end computing, two hardware trends have emerged as major contributors-high-speed networking technologies and multi-core architectures. Communication middleware such as the Message Passing Interface (MPI) uses the network technology for communicating between processes that reside on different physical nodes, while using shared memory for communicating between processes on different cores within the same node. Thus, two conflicting possibilities arise: (i) with the advent of multi-core architectures, the number of processes that reside on the same physical node and hence share the same physical network can potentially increase significantly, resulting in increased network usage, and (ii) given the increase in intra-node shared-memory communication for processes residing on the same node, the network usage can potentially decrease significantly. In this paper, we address these two conflicting possibilities and study the behavior of network usage in multi-core environments with sample scientific applications. Specifically, we analyze trends that result in increase or decrease of network usage, and we derive insights into application performance based on these. We also study the sharing of different resources in the system in multi-core environments and identify the contribution of the network in this mix. In addition, we study different process allocation strategies and analyze their impact on such network sharing.

  13. The Late Pliocene Eltanin Impact: Documentation From Sediment Core Analyses

    NASA Technical Reports Server (NTRS)

    Gersonde, R.; Kyte, F.; Flores, J. A.; Becquey, S.

    2002-01-01

    The expeditions ANT-XII/4 (1995) and ANT-XVIII/5a (2001) of the RV POLARSTERN collected extensive bathymetric and seismic data sets as well as sediment cores from an area in the Bellingshausen Sea (eastern Pacific Southern Ocean) that allow the first comprehensive geoscientific documentation of an asteroid impact into a deep ocean (approx. 5 km) basin, named the Eltanin impact. Impact deposits have now been recovered from a total of more than 20 sediment cores collected in an area covering about 80,000 km2. Combined biomagnetostratigraphic dating places the impact event into the earliest Matuyama Chron, a period of enhanced climate variability. Sediment texture analyses and studies of sediment composition including grain size and microfossil distribution reveal the pattern of impact- related sediment disturbance and the sedimentary processes immediately following the impact event. The pattern is complicated by the San Martin Seamounts (approx. 57.5 S, 91 W), a large topographic elevation that rises up to 3000 m above the surrounding abyssal plain in the area affected by the Eltanin impact. The impact ripped up sediments as old as Eocene and probably Paleocene that have been redeposited in a chaotic assemblage. This is followed by a sequence sedimented from a turbulent flow at the sea floor, overprinted by fall-out of airborne meteoritic ejecta that settled trough the water column. Grain size distribution reveals the timing and interaction of the different sedimentary processes. The gathered estimate of ejecta mass deposited over the studied area, composed of shock-melted asteroidal material and unmelted meteorites including fragments up to 2.5 cm in diameter, point to an Eltanin asteroid larger than the 1 km in diameter size originally suggested as a minimum based on the ANT-XII/4 results. This places the energy released by the impact at the threshold of those considered to cause environmental disturbance at a global scale and it makes the impact a likely transport

  14. Descriptions and preliminary interpretations of cores recovered from the Manson Impact Structure (Iowa)

    NASA Technical Reports Server (NTRS)

    Anderson, R. R.; Witzke, B. J.; Hartung, J. B.; Shoemaker, E. M.; Roddy, D. J.

    1993-01-01

    A core drilling program initiated by the Iowa Geological Survey Bureau and U.S. Geological Survey in 1991 and 1992 collected 12 cores totalling over 1200 m from the Manson Impact Structure, a probable K-T boundary structure located in north-central Iowa. Cores were recovered from each of the major structural terranes, with 2 cores (M-3 and M-4) from the Terrace Terrane, 4 cores (M-2, M-2A, M-6, and M-9) from the Crater Moat, and 6 cores (M-1, M-5, M-7, M-8, M-10, and M-11) from the Central Peak. These supplemented 2 central peak cores (1-A and 2-A) drilled in 1953. The cores penetrated five major impact lithologies: (1) sedimentary clast breccia; (2) impact ejecta; (3) central peak crystallite rocks; (4) crystalline clast breccia with sandy matrix; and (5) crystallite clast breccia with a melt matrix. Descriptions and preliminary interpretations of these cores are presented.

  15. Participation in health impact assessment: objectives, methods and core values.

    PubMed Central

    Wright, John; Parry, Jayne; Mathers, Jonathan

    2005-01-01

    Health impact assessment (HIA) is a multidisciplinary aid to decision-making that assesses the impact of policy on public health and on health inequalities. Its purpose is to assist decision-makers to maximize health gains and to reduce inequalities. The 1999 Gothenburg Consensus Paper (GCP) provides researchers with a rationale for establishing community participation as a core value of HIA. According to the GCP, participation in HIA empowers people within the decision-making process and redresses the democratic deficit between government and society. Participation in HIA generates a sense that health and decision-making is community-owned, and the personal experiences of citizens become integral to the formulation of policy. However, the participatory and empowering dimensions of HIA may prove difficult to operationalize. In this review of the participation strategies adopted in key applications of HIA in the United Kingdom, we found that HIA's aim of influencing decision-making creates tension between its participatory and knowledge-gathering dimensions. Accordingly, researchers have decreased the participatory dimension of HIA by reducing the importance attached to the community's experience of empowerment, ownership and democracy, while enlarging its knowledge-gathering dimension by giving pre-eminence to "expert" and "research-generated" evidence. Recent applications of HIA offer a serviceable rationale for participation as a means of information gathering and it is no longer tenable to uphold HIA as a means of empowering communities and advancing the aims of participatory democracy. PMID:15682250

  16. An examination of impact damage in glass-phenolic and aluminum honeycomb core composite panels

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.; Lance, D. G.; Hodge, A. J.

    1990-01-01

    An examination of low velocity impact damage to glass-phenolic and aluminum core honeycomb sandwich panels with carbon-epoxy facesheets is presented. An instrumented drop weight impact test apparatus was utilized to inflict damage at energy ranges between 0.7 and 4.2 joules. Specimens were checked for extent of damage by cross sectional examination. The effect of core damage was assessed by subjecting impact-damaged beams to four-point bend tests. Skin-only specimens (facings not bonded to honeycomb) were also tested for comparison purposes. Results show that core buckling is the first damage mode, followed by delaminations in the facings, matrix cracking, and finally fiber breakage. The aluminum honeycomb panels exhibited a larger core damage zone and more facing delaminations than the glass-phenolic core, but could withstand more shear stress when damaged than the glass-phenolic core specimens.

  17. Impact of inter-core crosstalk in radio-over-fiber transmission on multi-core optical media

    NASA Astrophysics Data System (ADS)

    Macho, Andrés.; Morant, Maria; Llorente, Roberto

    2016-02-01

    Optical transmission in multi-core optical media has the potential of great capacity and scalability for current and future optical networks. Optical fronthaul networks are expected to employ relatively high optical intensity levels when a large number of cores are connected to a large number of antennas. In this paper, the crosstalk characteristics of multi-core fiber operating in non-linear regime are identified, indicating advantageous performance in optical fronthaul radio-overfiber transmission. The nonlinear coupled-mode and coupled-power theories are revisited to demonstrate theoretically that the underlying Kerr effect mismatches the phase constant of the core modes reducing the mean and variance of the crosstalk when nonlinear regime is employed. This theoretical analysis is validated experimentally in this work using a homogeneous 4-core optical fiber in radio-over-fiber transmission for LTE fronthaul applications. In addition, the impact of the linear and nonlinear inter-core crosstalk in the error vector magnitude (EVM) is evaluated with the optical transmission of fully-standard LTE-Advanced signals using MIMO and SISO configurations operating in both linear and nonlinear power regimes.

  18. Differentiated planetesimal impacts into a terrestrial magma ocean: Fate of the iron core

    NASA Astrophysics Data System (ADS)

    Kendall, Jordan D.; Melosh, H. J.

    2016-08-01

    The abundance of moderately siderophile elements (;iron-loving;; e.g. Co, Ni) in the Earth's mantle is 10 to 100 times larger than predicted by chemical equilibrium between silicate melt and iron at low pressure, but it does match expectation for equilibrium at high pressure and temperature. Recent studies of differentiated planetesimal impacts assume that planetesimal cores survive the impact intact as concentrated masses that passively settle from a zero initial velocity and undergo turbulent entrainment in a global magma ocean; under these conditions, cores greater than 10 km in diameter do not fully mix without a sufficiently deep magma ocean. We have performed hydrocode simulations that revise this assumption and yield a clearer picture of the impact process for differentiated planetesimals possessing iron cores with radius = 100 km that impact into magma oceans. The impact process strips away the silicate mantle of the planetesimal and then stretches the iron core, dispersing the liquid iron into a much larger volume of the underlying liquid silicate mantle. Lagrangian tracer particles track the initially intact iron core as the impact stretches and disperses the core. The final displacement distance of initially closest tracer pairs gives a metric of core stretching. The statistics of stretching imply mixing that separates the iron core into sheets, ligaments, and smaller fragments, on a scale of 10 km or less. The impact dispersed core fragments undergo further mixing through turbulent entrainment as the molten iron fragments rain through the magma ocean and settle deeper into the planet. Our results thus support the idea that iron in the cores of even large differentiated planetesimals can chemically equilibrate deep in a terrestrial magma ocean.

  19. Impacts onto the Early Earth: Archean Spherule Layers from the ICDP Drill Core BARB5

    NASA Astrophysics Data System (ADS)

    Fritz, J. P.; Mohr-Westheide, T.; Reimold, W. U.; Schmitt, R. T.; Hofmann, A.; Koeberl, C.; McDonald, I.; Luais, B.; Tagle, R.; Schulz, T.; Mader, D.; Hoehnel, D.

    2014-09-01

    Geochemical and petrologic studies of the BARB5 ICDP drill core samples aim on identifying the “primary” signatures of the impact events least affected by (re)deposition and metamorphic overprint.

  20. The Impact of CORE Standards across the Rehabilitation Educational Continuum

    ERIC Educational Resources Information Center

    Leahy, Michael J.; Tansey, Timothy N.

    2008-01-01

    Since the establishment of the Council on Rehabilitation Education (CORE) in 1972, this regulatory organization has implemented a unique and highly innovative accreditation process that has had a profound effect on the standardization of curricula across this country and internationally. For the past 36 years, these standards have provided…

  1. How Will the Common Core Initiative Impact the Testing Industry?

    ERIC Educational Resources Information Center

    Toch, Thomas; Tyre, Peg

    2010-01-01

    The National Governors Association and the Council of Chief State School Officers have sponsored the development of common K-12 education standards in math and English/language arts--a project known as the Common Core State Standards Initiative (CCSSI)--in an effort to improve college readiness for the nation's students and replace the patchwork…

  2. Characterizing the impact of using spare-cores on application performance

    SciTech Connect

    Sancho Pitarch, Jose Carlos; Kerbyson, Darren J; Lang, Mike

    2010-01-01

    Increased parallelism on a single processor is driving improvements in peak-performance at both the node and system levels. However achievable performance, in particular from production scientific applications, is not always directly proportional to the core count. Performance is often limited by constraints in the memory hierarchy and also by a node interconnectivity. Even on state-of-the-art processors, containing between four and eight cores, many applications cannot take full advantage of the compute-performance of all cores. This trend is expected to increase on future processors as the core count per processor increases. In this work we characterize the use of spare-cores, cores that do not provide any improvements in application performance, on current multi-core processors. By using a pulse-width modulation method, we examine the possible performance profile of using a spare-core and quantify under what situations its use will not impact application performance. We show that, for current AMD and Intel multi-core processors, spare-cores can be used for substantial computational tasks but can impact application performance when using shared caches or when significantly accessing main memory.

  3. Physical property data from the ICDP-USGS Eyreville cores A and B, Chesapeake Bay impact structure, Virginia, USA, acquired using a multisensor core logger

    USGS Publications Warehouse

    Pierce, H.A.; Murray, J.B.

    2009-01-01

    The International Continental Scientific Drilling Program (ICDP) and the U.S. Geological Survey (USGS) drilled three core holes to a composite depth of 1766 m within the moat of the Chesapeake Bay impact structure. Core recovery rates from the drilling were high (??90%), but problems with core hole collapse limited the geophysical downhole logging to natural-gamma and temperature logs. To supplement the downhole logs, ??5% of the Chesapeake Bay impact structure cores was processed through the USGS GeoTek multisensor core logger (MSCL) located in Menlo Park, California. The measured physical properties included core thickness (cm), density (g cm-3), P-wave velocity (m s-1), P-wave amplitude (%), magnetic susceptibility (cgs), and resistivity (ohm-m). Fractional porosity was a secondary calculated property. The MSCL data-sampling interval for all core sections was 1 cm longitudinally. Photos of each MSCL sampled core section were imbedded with the physical property data for direct comparison. These data have been used in seismic, geologic, thermal history, magnetic, and gravity models of the Chesapeake Bay impact structure. Each physical property curve has a unique signature when viewed over the full depth of the Chesapeake Bay impact structure core holes. Variations in the measured properties reflect differences in pre-impact target-rock lithologies and spatial variations in impact-related deformation during late-stage crater collapse and ocean resurge. ?? 2009 The Geological Society of America.

  4. Scientific Drilling of Impact Craters - Well Logging and Core Analyses Using Magnetic Methods (Invited)

    NASA Astrophysics Data System (ADS)

    Fucugauchi, J. U.; Perez-Cruz, L. L.; Velasco-Villarreal, M.

    2013-12-01

    Drilling projects of impact structures provide data on the structure and stratigraphy of target, impact and post-impact lithologies, providing insight on the impact dynamics and cratering. Studies have successfully included magnetic well logging and analyses in core and cuttings, directed to characterize the subsurface stratigraphy and structure at depth. There are 170-180 impact craters documented in the terrestrial record, which is a small proportion compared to expectations derived from what is observed on the Moon, Mars and other bodies of the solar system. Knowledge of the internal 3-D deep structure of craters, critical for understanding impacts and crater formation, can best be studied by geophysics and drilling. On Earth, few craters have yet been investigated by drilling. Craters have been drilled as part of industry surveys and/or academic projects, including notably Chicxulub, Sudbury, Ries, Vredefort, Manson and many other craters. As part of the Continental ICDP program, drilling projects have been conducted on the Chicxulub, Bosumtwi, Chesapeake, Ries and El gygytgyn craters. Inclusion of continuous core recovery expanded the range of paleomagnetic and rock magnetic applications, with direct core laboratory measurements, which are part of the tools available in the ocean and continental drilling programs. Drilling studies are here briefly reviewed, with emphasis on the Chicxulub crater formed by an asteroid impact 66 Ma ago at the Cretaceous/Paleogene boundary. Chicxulub crater has no surface expression, covered by a kilometer of Cenozoic sediments, thus making drilling an essential tool. As part of our studies we have drilled eleven wells with continuous core recovery. Magnetic susceptibility logging, magnetostratigraphic, rock magnetic and fabric studies have been carried out and results used for lateral correlation, dating, formation evaluation, azimuthal core orientation and physical property contrasts. Contributions of magnetic studies on impact

  5. Columbia Public Health Core Curriculum: Short-Term Impact.

    PubMed

    Begg, Melissa D; Fried, Linda P; Glover, Jim W; Delva, Marlyn; Wiggin, Maggie; Hooper, Leah; Saxena, Roheeni; de Pinho, Helen; Slomin, Emily; Walker, Julia R; Galea, Sandro

    2015-12-01

    We evaluated a transformed core curriculum for the Columbia University, Mailman School of Public Health (New York, New York) master of public health (MPH) degree. The curriculum, launched in 2012, aims to teach public health as it is practiced: in interdisciplinary teams, drawing on expertise from multiple domains to address complex health challenges. We collected evaluation data starting when the first class of students entered the program and ending with their graduation in May 2014. Students reported being very satisfied with and challenged by the rigorous curriculum and felt prepared to integrate concepts across varied domains and disciplines to solve public health problems. This novel interdisciplinary program could serve as a prototype for other schools that wish to reinvigorate MPH training.

  6. To core, or not to core: the impact of coring on tree health and a best-practice framework for collecting dendrochronological information from living trees.

    PubMed

    Tsen, Edward W J; Sitzia, Tommaso; Webber, Bruce L

    2016-11-01

    Trees are natural repositories of valuable environmental information that is preserved in the growth and structure of their stems, branches and roots. Dendrochronological analyses, based on the counting, crossdating and characterisation of incrementally formed wood rings, offer powerful insights for diverse fields including ecology, climatology and archaeology. The application of this toolset is likely to increase in popularity over coming decades due to advances in the field and a reduction in the cost of analyses. In research settings where the continued value of living trees subject to dendrochronological investigation is important, the use of an increment bore corer to extract trunk tissue is considered the best option to minimise negative impacts on tree health (e.g. stress and fitness). A small and fragmented body of literature, however, reports significant after-effects, and in some cases fatal outcomes, from this sampling technique. As it stands, the literature documenting increment bore coring (IBC) impacts lacks experimental consistency and is poorly replicated, making it difficult for prospective users of the method to assess likely tree responses to coring. This paucity of information has the potential to lead to destructive misuse of the method and also limits its safe implementation in circumstances where the risk of impacts may be appropriate. If IBC is to fulfil its potential as a method of choice across research fields, then we must first address our limited understanding of IBC impacts and provide a framework for its appropriate future use. Firstly, we review the historical context of studies examining the impacts of IBC on trees to identify known patterns, focal issues and biases in existing knowledge. IBC wound responses, particularly those that impact on lumber quality, have been the primary focus of prior studies. No universal treatment was identified that conclusively improved wound healing and few studies have linked wound responses to tree

  7. IMPaCT - Integration of Missions, Programs, and Core Technologies

    NASA Technical Reports Server (NTRS)

    Balacuit, Carlos P.; Cutts, James A.; Peterson, Craig E.; Beauchamp, Patricia M.; Jones, Susan K.; Hang, Winnie N.; Dastur, Shahin D.

    2013-01-01

    IMPaCT enables comprehensive information on current NASA missions, prospective future missions, and the technologies that NASA is investing in, or considering investing in, to be accessed from a common Web-based interface. It allows dependencies to be established between missions and technology, and from this, the benefits of investing in individual technologies can be determined. The software also allows various scenarios for future missions to be explored against resource constraints, and the nominal cost and schedule of each mission to be modified in an effort to fit within a prescribed budget.

  8. EMBRYO IMPACTS AND GAS GIANT MERGERS. I. DICHOTOMY OF JUPITER AND SATURN's CORE MASS

    SciTech Connect

    Li Shulin; Agnor, C.B.; Lin, D. N. C.

    2010-09-10

    Interior to the gaseous envelopes of Saturn, Uranus, and Neptune, there are high-density cores with masses larger than 10 Earth masses. According to the conventional sequential accretion hypothesis, such massive cores are needed for the onset of efficient accretion of their gaseous envelopes. However, Jupiter's gaseous envelope is more massive and its core may be less massive than those of Saturn. In order to account for this structural diversity and the super-solar metallicity in the envelope of Jupiter and Saturn, we investigate the possibility that they may have either merged with other gas giants or consumed several Earth-mass protoplanetary embryos during or after the rapid accretion of their envelope. In general, impinging sub-Earth-mass planetesimals disintegrate in gas giants' envelopes, deposit heavy elements well outside the cores, and locally suppress the convection. Consequently, their fragments sediment to promote the growth of cores. Through a series of numerical simulations, we show that it is possible for colliding super-Earth-mass embryos to reach the cores of gas giants. Direct parabolic collisions also lead to the coalescence of gas giants and merging of their cores. In these cases, the energy released from the impact leads to vigorous convective motion throughout the envelope and the erosion of the cores. This dichotomy contributes to the observed dispersion in the internal structure and atmospheric composition between Jupiter and Saturn and other gas giant planets and elsewhere.

  9. Low-Velocity Impact Response of Sandwich Beams with Functionally Graded Core

    NASA Technical Reports Server (NTRS)

    Apetre, N. A.; Sankar, B. V.; Ambur, D. R.

    2006-01-01

    The problem of low-speed impact of a one-dimensional sandwich panel by a rigid cylindrical projectile is considered. The core of the sandwich panel is functionally graded such that the density, and hence its stiffness, vary through the thickness. The problem is a combination of static contact problem and dynamic response of the sandwich panel obtained via a simple nonlinear spring-mass model (quasi-static approximation). The variation of core Young's modulus is represented by a polynomial in the thickness coordinate, but the Poisson's ratio is kept constant. The two-dimensional elasticity equations for the plane sandwich structure are solved using a combination of Fourier series and Galerkin method. The contact problem is solved using the assumed contact stress distribution method. For the impact problem we used a simple dynamic model based on quasi-static behavior of the panel - the sandwich beam was modeled as a combination of two springs, a linear spring to account for the global deflection and a nonlinear spring to represent the local indentation effects. Results indicate that the contact stiffness of thc beam with graded core Increases causing the contact stresses and other stress components in the vicinity of contact to increase. However, the values of maximum strains corresponding to the maximum impact load arc reduced considerably due to grading of thc core properties. For a better comparison, the thickness of the functionally graded cores was chosen such that the flexural stiffness was equal to that of a beam with homogeneous core. The results indicate that functionally graded cores can be used effectively to mitigate or completely prevent impact damage in sandwich composites.

  10. Effect of a Thin Soft Core on the Impact Behaviour of CFRP Laminates

    NASA Astrophysics Data System (ADS)

    Caprino, Giancarlo; Lopresto, Valentina; Riccio, Massimo; Leone, Claudio

    2012-04-01

    Low-velocity impact tests were carried out on sandwich plates having CFRP facings and thin rubbery core. Two types of cores, differing in the material nature and thickness, were used. For comparison, similar tests were performed on the monolithic laminate. Various impact parameters, among which indentation, first failure energy, perforation energy, absorbed energy and maximum contact force, were analyzed, to highlight the effect of the core on the material response. The influence of the core on the macroscopic behaviour of the panels was quite limited, except in the elastic phase, where the lower stiffness of the sandwich configurations resulted in a higher energy at first failure. More relevant differences were found from the study of failure modes, carried out combining ultrasonic C-scan and a limited number of microscopic observations. In particular, in correspondence of the energy for barely visible impact damage, besides considerable facing-core debonding, both the facings of the sandwich structures exhibited fibre breakage at their back side.

  11. Beyond the Common Core: Examining 20 Years of Literacy Priorities and Their Impact on Struggling Readers

    ERIC Educational Resources Information Center

    Cassidy, Jack; Ortlieb, Evan; Grote-Garcia, Stephanie

    2016-01-01

    Researchers utilized a historical context of the "What's Hot, What's Not" expert surveys over the last 20 years to examine literacy priorities and possible impacts. The Common Core State Standards (CCSS) were recently recognized as the hottest topic in the field of literacy education. Perhaps one of the unintended consequences of this…

  12. The Chicxulub impact structure: What does the Yaxcopoil-1 drill core reveal?

    NASA Astrophysics Data System (ADS)

    Elbra, T.

    2013-05-01

    The Chicxulub impact structure, one of the largest impact structures on Earth, was formed 65 Ma by hypervelocity impact which led to the large mass-extinction at K-Pg boundary. This well preserved but buried structure has undergone numerous drillings and studies aimed to understand the formation mechanism, structure and age of the crater. The Yaxcopoil-1 (Yax-1) drill core, located in the southern sector of the Chicxulub crater, in the outer part of an annular trough, 62 km from the crater center, was drilled by ICDP in 2001-2002. Petrophysical, rock- and paleomagnetic studies of Yax-1 (Elbra and Pesonen, 2011) showed that physical properties characterize the various lithological units. Dependence on mineral composition rather than fabric was observed in pre-impact lithologies contrarily to the post-impact and impact rocks where the physical properties were dominated by porosity and reflected, in case of impactites, the impact formation mechanism with its numerous features resulting from melting, brecciation and fracturing. Furthermore, while the pre- and post-impact lithologies in Yax-1 are mostly dia- or paramagnetic, the impactite units indicated enhanced magnetizations and the presence of ferromagnetic, probably hydrothermally deposited magnetite and pyrrhotite. The sharp contrast of the impactites to the target and to post-impact lithologies allowed establishing the contact (especially the K-Pg boundary) between. The anisotropy, shape and orientation of the magnetic fraction illustrated the fabric randomization and showed the influence of impact-related redeposition and hydrothermal activity. The paleomagnetic data suggested that the Chicxulub impact occurred during the reverse polarity geomagnetic chron 29R, which is in agreement with the isotopic dates of the Chicxulub impact as well as with expected K-Pg boundary polarity. Reference Elbra, T. and Pesonen, L.J., 2011. Physical properties of the Yaxcopoil-1 deep drill core, Chicxulub impact structure, Mexico

  13. Manson impact structure, Iowa: First geochemical results for drill core M-1

    NASA Technical Reports Server (NTRS)

    Koeberl, Christian; Anderson, Raymond R.; Hartung, Jack B.; Reimold, Wolf Uwe

    1993-01-01

    The Manson Impact Structure is a large complex impact crater centered ca. S km north of the town of Manson, Iowa. It is the largest intact impact structure recognized in the United States (35 km in diameter). Its Ar-40/Ar-39 age is indistinguishable from that of the Cretaceous-Tertiary (K-T) boundary. The Manson structure may be one element of the events at the K-T boundary. The crater is completely covered by Quaternary glacial sedimentary deposits that are normally underlain by Cretaceous clastic sediments and flat-lying carbonate sediments of Phanerozoic age, as well as Proterozoic red clastic, metamorphic, volcanic, and plutonic rock sequences. The study of a reflection seismic profile, provided by Amoco, was critical in interpreting the structure. In the 35 km diameter zone that marks the extension of the crater the normal rock sequence is disturbed due to the impact, and at the center of the structure granitic basement rocks are present that have been uplifted from about 4 km depth. Our studies consist of detailed petrological and geochemical characterization of all cores, with emphasis on a detailed description of all rock types found in the core samples and their relationship to target rocks. Geochemical data on samples from the Manson M-1 core are presented.

  14. Impact of Quad-core Cray XT4 System and Software Stack on Scientific Computation

    SciTech Connect

    Alam, Sadaf R; Barrett, Richard F; Jagode, Heike; Kuehn, Jeffery A; Poole, Stephen W; Sankaran, Ramanan

    2009-01-01

    An upgrade from dual-core to quad-core AMD processor on the Cray XT system at the Oak Ridge National Laboratory (ORNL) Leadership Computing Facility (LCF) has resulted in significant changes in the hardware and software stack, including a deeper memory hierarchy, SIMD instructions and a multi-core aware MPI library. In this paper, we evaluate impact of a subset of these key changes on large-scale scientific applications. We will provide insights into application tuning and optimization process and report on how different strategies yield varying rates of successes and failures across different application domains. For instance, we demonstrate that the vectorization instructions (SSE) provide a performance boost of as much as 50% on fusion and combustion applications. Moreover, we reveal how the resource contentions could limit the achievable performance and provide insights into how application could exploit Petascale XT5 system's hierarchical parallelism.

  15. Hypervelocity Impact Performance of Open Cell Foam Core Sandwich Panel Structures

    NASA Technical Reports Server (NTRS)

    Ryan, Shannon; Christiansen, Eric; Lear, Dana

    2009-01-01

    Metallic foams are a relatively new class of materials with low density and novel physical, mechanical, thermal, electrical and acoustic properties. Although incompletely characterized, they offer comparable mechanical performance to traditional spacecraft structural materials (i.e. honeycomb sandwich panels) without detrimental through-thickness channeling cells. There are two competing types of metallic foams: open cell and closed cell. Open cell foams are considered the more promising technology due to their lower weight and higher degree of homogeneity. Leading micrometeoroid and orbital debris shields (MMOD) incorporate thin plates separated by a void space (i.e. Whipple shield). Inclusion of intermediate fabric layers, or multiple bumper plates have led to significant performance enhancements, yet these shields require additional non-ballistic mass for installation (fasteners, supports, etc.) that can consume up to 35% of the total shield weight [1]. Structural panels, such as open cell foam core sandwich panels, that are also capable of providing sufficient MMOD protection, represent a significant potential for increased efficiency in hypervelocity impact shielding from a systems perspective through a reduction in required non-ballistic mass. In this paper, the results of an extensive impact test program on aluminum foam core sandwich panels are reported. The effect of pore density, and core thickness on shielding performance have been evaluated over impact velocities ranging from 2.2 - 9.3 km/s at various angles. A number of additional tests on alternate sandwich panel configurations of comparable-weight have also been performed, including aluminum honeycomb sandwich panels (see Figure 1), Nomex honeycomb core sandwich panels, and 3D aluminum honeycomb sandwich panels. A total of 70 hypervelocity impact tests are reported, from which an empirical ballistic limit equation (BLE) has been derived. The BLE is in the standard form suitable for implementation in

  16. Compression After Impact on Honeycomb Core Sandwich Panels With Thin Facesheets. Part 1; Experiments

    NASA Technical Reports Server (NTRS)

    McQuigg, Thomas D.; Kapania, Rakesh K.; Scotti, Stephen J.; Walker, Sandra P.

    2012-01-01

    A two part research study has been completed on the topic of compression after impact (CAI) of thin facesheet honeycomb core sandwich panels. The research has focused on both experiments and analysis in an effort to establish and validate a new understanding of the damage tolerance of these materials. Part one, the subject of the current paper, is focused on the experimental testing. Of interest are sandwich panels, with aerospace applications, which consist of very thin, woven S2-fiberglass (with MTM45-1 epoxy) facesheets adhered to a Nomex honeycomb core. Two sets of specimens, which were identical with the exception of the density of the honeycomb core, were tested. Static indentation and low velocity impact using a drop tower are used to study damage formation in these materials. A series of highly instrumented CAI tests was then completed. New techniques used to observe CAI response and failure include high speed video photography, as well as digital image correlation (DIC) for full-field deformation measurement. Two CAI failure modes, indentation propagation, and crack propagation, were observed. From the results, it can be concluded that the CAI failure mode of these panels depends solely on the honeycomb core density.

  17. Physical Properties of Suevite Section of the Eyreville Core, Chesapeake Bay Impact Structure

    NASA Astrophysics Data System (ADS)

    Elbra, T.; Pesonen, L. J.

    2007-12-01

    Chesapeake is a 35 Ma old shallow marine, complex impact structure with a diameter of ca. 85 km. The structure has previously been mapped with shallow drillings. Recently, the deep drilling into inner crater zone near Cape Charles was carried out in order to provide constraints on cratering processes in multi-layered marine targets. The Eyreville-1 core includes three holes with total depth of 1766m (Gohn et al. 2006). We are analyzing the fragments of the Eyreville core including post-impact, impact and basement units of the structure. The sampling interval was chosen dense enough to allow high-resolution petrophysical, paleomagnetic and rock magnetic data to be extracted from the core. Hereby we report the preliminary petrophysical and rock-magnetic data from suevite section of Eyreville core B. Results obtained so far show large variations in magnetic susceptibility data of suevite section. Polymict lithic breccias and cataclasites in lower part of the section are characterized by low magnetic susceptibility (below 0.0003 SI). The upper part, however, consists of more magnetic (susceptibility up to 0.006 SI) suevites. The rock- magnetic measurements (including thermal behavior of magnetic susceptibility and magnetic hysteresis) show the presence of magnetites in lower part of the section. Upper part shows additionally a distinct change in the slope of the susceptibility curve also near 350C, which may indicate the presence of pyrrhotites or maghemites. More extensive studies will be applied in near future in order to clarify the magnetomineralogy and will be presented. References: G. S. Gohn, C. Koeberl, K. G. Miller, W. U. Reimold, C. S. Cockell, J. W. Horton, W. E. Sanford, M. A. Voytek, 2006. Chesapeake Bay Impact Structure Drilled. EOS, vol 87. nr 35

  18. Compression After Impact Experiments and Analysis on Honeycomb Core Sandwich Panels with Thin Facesheets

    NASA Technical Reports Server (NTRS)

    McQuigg, Thomas D.

    2011-01-01

    A better understanding of the effect of impact damage on composite structures is necessary to give the engineer an ability to design safe, efficient structures. Current composite structures suffer severe strength reduction under compressive loading conditions, due to even light damage, such as from low velocity impact. A review is undertaken to access the current state-of-development in the areas of experimental testing, and analysis methods. A set of experiments on honeycomb core sandwich panels, with thin woven fiberglass cloth facesheets, is described, which includes detailed instrumentation and unique observation techniques.

  19. Chicxulub Impact Crater and Yucatan Carbonate Platform - Stratigraphy and Petrography of PEMEX Borehole Cores

    NASA Astrophysics Data System (ADS)

    Gutierrez-Cirlos, A. G.; Perez-Drago, G.; Perez-Cruz, L.; Urrutia-Fucugauchi, J.

    2008-12-01

    Chicxulub impact crater is the best preserved of the three large multi-ring structures documented in the terrestrial record. Chicxulub, formed 65 Ma ago, is associated with the Cretaceous/Tertiary (K/T) boundary layer and the impact related to the organism extinctions and events marking the boundary. The crater is buried under Tertiary sediments in the Yucatan carbonate platform in the southern Gulf of Mexico. The structure was initially recognized from gravity and magnetic anomalies in the PEMEX exploration surveys of the northwestern Yucatan peninsula. The exploration program included eight deep boreholes completed from 1952 through the 1970s. The investigations showing Chicxulub as a large complex impact crater formed at the K/T boundary have relayed on the PEMEX decades-long exploration program. However, despite frequent use of PEMEX information and core samples, significant parts of the database and cores remain to be evaluated, analyzed and incorporated with results from recent efforts. Access to PEMEX Core Repository has permitted to study the cores and collect new samples from some of the boreholes. We analyzed cores from Yucatan-6, Chicxulub-1, Sacapuc-1, Ticul-1, Yucatan-1 and Yucatan-4 boreholes to make new detailed stratigraphic correlations and petrographic characterization, using information from PEMEX database and the recent studies. In C-1 cores, breccias show 4-8 cm clasts of fine grained altered melt dispersed in a medium to coarse grained matrix composed of pyroxene and feldspar with little macroscopic alteration. Clasts contain 0.2 to 0.1 cm fragments of silicate material (basement) that show variable degrees of digestion. Melt samples from C-1 N10 comes from interval 1,393-1,394 m, and show a fine-to-medium grained coherent microcrystalline groundmass. Melt and breccias in Y-6 extend from about 1,100 m to more than 1,400 m. Sequence is well sorted, with an apparent gradation in both the lithic and melt clasts. In this presentation we report on

  20. 3-D numerical simulations of a growing planet with the core formation by the impact

    NASA Astrophysics Data System (ADS)

    Furuichi, M.; Nakagawa, T.

    2011-12-01

    The formation of a metallic core is widely accepted as the biggest differentiation event during the final stage of the planetary formation [e.g. Stevenson, 1990]. The early Earth hypothesis also suggested that the core formation process would be an important for understanding the initial condition (both thermal and chemical) of mantle convection [Labrosse et al., 2007]. Although the formation process of metallic core is still not clear, it is clear that the different time-scale of dynamics in solid and liquid contribute to that. Here, we assume the scenario that the planetesimal impact induces a significant volume of melt which laterally spreads over the global (magma ocean) or regional area (magma pond) in the short crystallization time scale (~300yr) [Reese and Solomatov, 2006]. After the solidification of magma ocean/pond, hot metallic and silicate rich layers are created [e.g. Senshu et al., 2002]. Since the heavy metal rich material causes the gravitational instability in the viscous planet's interior, the planetary core would form with sinking the metallic material into the center. The silicate layer which floods from the magma pond, deforms as a viscous flow on the planetary surface due to the isostatic adjustment. A series of event on the core formation would have the time-scale of ~100 Mys at the maximum. In order to investigate the scenario described above, we developed the simulation code to solve the Stokes flow with the free surface under the self-gravitating field in 3-D, designed for the massively parallel/vector supercomputer system Earth Simulator 2(ES2) [Furuichi, 2011]. Expressing the free surface motion, a stick air layer, which is the low viscosity layer surrounding the planetary surface, is assumed [e.g. Furuichi et al, 2009]. An ill conditioned Stokes problem of the finite difference discretization on a staggered grid, is solved by iterative Stokes flow solver, robust to large viscosity jumps, using a strong Schur complement preconditioner

  1. Compression After Impact on Honeycomb Core Sandwich Panels with Thin Facesheets, Part 2: Analysis

    NASA Technical Reports Server (NTRS)

    Mcquigg, Thomas D.; Kapania, Rakesh K.; Scotti, Stephen J.; Walker, Sandra P.

    2012-01-01

    A two part research study has been completed on the topic of compression after impact (CAI) of thin facesheet honeycomb core sandwich panels. The research has focused on both experiments and analysis in an effort to establish and validate a new understanding of the damage tolerance of these materials. Part 2, the subject of the current paper, is focused on the analysis, which corresponds to the CAI testings described in Part 1. Of interest, are sandwich panels, with aerospace applications, which consist of very thin, woven S2-fiberglass (with MTM45-1 epoxy) facesheets adhered to a Nomex honeycomb core. Two sets of materials, which were identical with the exception of the density of the honeycomb core, were tested in Part 1. The results highlighted the need for analysis methods which taken into account multiple failure modes. A finite element model (FEM) is developed here, in Part 2. A commercial implementation of the Multicontinuum Failure Theory (MCT) for progressive failure analysis (PFA) in composite laminates, Helius:MCT, is included in this model. The inclusion of PFA in the present model provided a new, unique ability to account for multiple failure modes. In addition, significant impact damage detail is included in the model. A sensitivity study, used to assess the effect of each damage parameter on overall analysis results, is included in an appendix. Analysis results are compared to the experimental results for each of the 32 CAI sandwich panel specimens tested to failure. The failure of each specimen is predicted using the high-fidelity, physicsbased analysis model developed here, and the results highlight key improvements in the understanding of honeycomb core sandwich panel CAI failure. Finally, a parametric study highlights the strength benefits compared to mass penalty for various core densities.

  2. Supplemental materials for the ICDP-USGS Eyreville A, B, and C core holes, Chesapeake Bay impact structure: Core-box photographs, coring-run tables, and depth-conversion files

    USGS Publications Warehouse

    Durand, C.T.; Edwards, L.E.; Malinconico, M.L.; Powars, D.S.

    2009-01-01

    During 2005-2006, the International Continental Scientific Drilling Program and the U.S. Geological Survey drilled three continuous core holes into the Chesapeake Bay impact structure to a total depth of 1766.3 m. A collection of supplemental materials that presents a record of the core recovery and measurement data for the Eyreville cores is available on CD-ROM at the end of this volume and in the GSA Data Repository. The supplemental materials on the CD-ROM include digital photographs of each core box from the three core holes, tables of the three coring-run logs, as recorded on site, and a set of depth-conversion programs. In this chapter, the contents, purposes, and basic applications of the supplemental materials are briefly described. With this information, users can quickly decide if the materials will apply to their specific research needs. ?? 2009 The Geological Society of America.

  3. Contamination assessment in microbiological sampling of the Eyreville core, Chesapeake Bay impact structure

    USGS Publications Warehouse

    Gronstal, A.L.; Voytek, M.A.; Kirshtein, J.D.; Von der, Heyde; Lowit, M.D.; Cockell, C.S.

    2009-01-01

    Knowledge of the deep subsurface biosphere is limited due to difficulties in recovering materials. Deep drilling projects provide access to the subsurface; however, contamination introduced during drilling poses a major obstacle in obtaining clean samples. To monitor contamination during the 2005 International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) deep drilling of the Chesapeake Bay impact structure, four methods were utilized. Fluorescent microspheres were used to mimic the ability of contaminant cells to enter samples through fractures in the core material during retrieval. Drilling mud was infused with a chemical tracer (Halon 1211) in order to monitor penetration of mud into cores. Pore water from samples was examined using excitation-emission matrix (EEM) fl uorescence spectroscopy to characterize dissolved organic carbon (DOC) present at various depths. DOC signatures at depth were compared to signatures from drilling mud in order to identify potential contamination. Finally, microbial contaminants present in drilling mud were identified through 16S ribosomal deoxyribonucleic acid (rDNA) clone libraries and compared to species cultured from core samples. Together, these methods allowed us to categorize the recovered core samples according to the likelihood of contamination. Twenty-two of the 47 subcores that were retrieved were free of contamination by all the methods used and were subsequently used for microbiological culture and culture-independent analysis. Our approach provides a comprehensive assessment of both particulate and dissolved contaminants that could be applied to any environment with low biomass. ?? 2009 The Geological Society of America.

  4. Petrophysical and paleomagnetic data of drill cores from the Bosumtwi impact structure, Ghana

    NASA Astrophysics Data System (ADS)

    Elbra, T.; Kontny, A.; Pesonen, L. J.; Schleifer, N.; Schell, C.

    Physical properties from rocks of the Bosumtwi impact structure, Ghana, Central Africa, are essential to understand the formation of the relatively young (1.07 Ma) and small (10.5 km) impact crater and to improve its geophysical modeling. Results of our petrophysical studies of deep drill cores LB-07A and LB-08A reveal distinct lithological patterns but no depth dependence. The most conspicuous difference between impactites and target lithologies are the lower bulk densities and significantly higher porosities of the suevite and lithic breccia units compared to meta-graywacke and metapelites of target lithologies. Magnetic susceptibility shows mostly paramagnetic values (200-500 × 10-6 SI) throughout the core, with an exception of a few metasediment samples, and correlates positively with natural remanent magnetization (NRM) and Q values. These data indicate that magnetic parameters are related to inhomogeneously distributed ferrimagnetic pyrrhotite. The paleomagnetic data reveals that the characteristic direction of NRM has shallow normal (in a few cases shallow reversed) polarity, which is in agreement with the Lower Jaramillo N-polarity chron direction, and is carried by ferrimagnetic pyrrhotite. However, our study has not revealed the expected high magnetization body required from previous magnetic modeling. Furthermore, the LB-07A and LB08-A drill cores did not show the predicted high content of melt in the rocks, requiring a new interpretation model for magnetic data.

  5. Geology and geochemistry of shallow drill cores from the Bosumtwi impact struture, Ghana

    NASA Astrophysics Data System (ADS)

    Boamah, D.; Koeberl, C.

    2003-08-01

    The 1.07 Ma well-preserved Bosumtwi impact structure in Ghana (10.5 km in diameter) formed in 2 Ga-old metamorphosed and crystalline rocks of the Birimian system. The interior of the structure is largely filled by the 8 km diameter Lake Bosumtwi, and the crater rim and region in the environs of the crater is covered by tropical rainforest, making geological studies rather difficult and restricted to road cuts and streams. In early 1999, we undertook a shallow drilling program to the north of the crater rim to determine the extent of the ejecta blanket around the crater and to obtain subsurface core samples for mineralogical, petrological, and geochemical studies of ejecta of the Bosumtwi impact structure. A variety of impactite lithologies are present, consisting of impact glass- rich suevite and several types of breccia: lithic breccia of single rock type, often grading into unbrecciated rock, with the rocks being shattered more or less in situ without much relative displacement (autochthonous?), and lithic polymict breccia that apparently do not contain any glassy material (allochtonous?). The suevite cores show that melt inclusions are present throughout the whole length of the cores in the form of vesicular glasses with no significant change of abundance with depth. Twenty samples from the 7 drill cores and 4 samples from recent road cuts in the structure were studied for their geochemical characteristics to accumulate a database for impact lithologies and their erosion products present at the Bosumtwi crater. Major and trace element analyses yielded compositions similar to those of the target rocks in the area (graywacke-phyllite, shale, and granite). Graywacke-phyllite and granite dikes seem to be important contributors to the compositions of the suevite and the road cut samples (fragmentary matrix), with a minor contribution of Pepiakese granite. The results also provide information about the thickness of the fallout suevite in the northern part of the

  6. [Signs of the Impact of the Earth's core on the Planet's Population].

    PubMed

    Malyshkov, Yu P; Malyshkov, S Yu

    2015-01-01

    When investigating the rhythms of the Earth's electromagnetic noise and seismicity, as well as numerous calls for ambulance, cases of baby births and people death, the authors have found that such rhythms have diurnal, seasonal and annual variations and they are principal for human being's life. The analysis of both main regularities and single peculiarities of diurnal and annual rhythms in the living and non-living nature has led us to assumption that the deep-seated processes relating. to the eccentric rotation of the Earth's core and shell could be a powerful conductor of the life and the death on the Earth. The results obtained in our study not only confirm the existence of deep-seated waves generated by the Earth's core but also make us sure that such constantly circulating waves produce a certain impact on a human being's health, birth and death and even "orchestrate" suicides.

  7. Nonlinear seismic analysis of a reactor structure impact between core components

    NASA Technical Reports Server (NTRS)

    Hill, R. G.

    1975-01-01

    The seismic analysis of the FFTF-PIOTA (Fast Flux Test Facility-Postirradiation Open Test Assembly), subjected to a horizontal DBE (Design Base Earthquake) is presented. The PIOTA is the first in a set of open test assemblies to be designed for the FFTF. Employing the direct method of transient analysis, the governing differential equations describing the motion of the system are set up directly and are implicitly integrated numerically in time. A simple lumped-nass beam model of the FFTF which includes small clearances between core components is used as a "driver" for a fine mesh model of the PIOTA. The nonlinear forces due to the impact of the core components and their effect on the PIOTA are computed.

  8. Evidence of strong projectile-target-core interaction in single ionization of neon by electron impact

    SciTech Connect

    Yan, S.; Zhang, P.; Xu, S.; Ma, X.; Zhang, S. F.; Zhu, X. L.; Feng, W. T.; Liu, H. P.

    2010-11-15

    The momentum distributions of recoil ions were measured in the single ionization of neon by electron impact at incident energies between 80 and 2300 eV. It was found that there are a noticeable number of recoil ions carrying large momenta, and the relative contributions of these ions becomes more pronounced with the further decrease of incident electron energy. These observed behaviors indicate that there is a strong projectile-target-core interaction in the single-ionization reaction. By comparing our results with those of electron-neon elastic scattering, we concluded that the elastic scattering of the projectile electron on the target core plays an important role at low and intermediate collision energies.

  9. Hypervelocity Impact Performance of Open Cell Foam Core Sandwich Panel Structures

    NASA Technical Reports Server (NTRS)

    Ryan, S.; Ordonez, E.; Christiansen, E. L.; Lear, D. M.

    2010-01-01

    Open cell metallic foam core sandwich panel structures are of interest for application in spacecraft micrometeoroid and orbital debris shields due to their novel form and advantageous structural and thermal performance. Repeated shocking as a result of secondary impacts upon individual foam ligaments during the penetration process acts to raise the thermal state of impacting projectiles ; resulting in fragmentation, melting, and vaporization at lower velocities than with traditional shielding configurations (e.g. Whipple shield). In order to characterize the protective capability of these structures, an extensive experimental campaign was performed by the Johnson Space Center Hypervelocity Impact Technology Facility, the results of which are reported in this paper. Although not capable of competing against the protection levels achievable with leading heavy shields in use on modern high-risk vehicles (i.e. International Space Station modules), metallic foam core sandwich panels are shown to provide a substantial improvement over comparable structural panels and traditional low weight shielding alternatives such as honeycomb sandwich panels and metallic Whipple shields. A ballistic limit equation, generalized in terms of panel geometry, is derived and presented in a form suitable for application in risk assessment codes.

  10. CERN antiproton target: Hydrocode analysis of its core material dynamic response under proton beam impact

    NASA Astrophysics Data System (ADS)

    Martin, Claudio Torregrosa; Perillo-Marcone, Antonio; Calviani, Marco; Muñoz-Cobo, José-Luis

    2016-07-01

    Antiprotons are produced at CERN by colliding a 26 GeV /c proton beam with a fixed target made of a 3 mm diameter, 55 mm length iridium core. The inherent characteristics of antiproton production involve extremely high energy depositions inside the target when impacted by each primary proton beam, making it one of the most dynamically demanding among high energy solid targets in the world, with a rise temperature above 2000 °C after each pulse impact and successive dynamic pressure waves of the order of GPa's. An optimized redesign of the current target is foreseen for the next 20 years of operation. As a first step in the design procedure, this numerical study delves into the fundamental phenomena present in the target material core under proton pulse impact and subsequent pressure wave propagation by the use of hydrocodes. Three major phenomena have been identified, (i) the dominance of a high frequency radial wave which produces destructive compressive-to-tensile pressure response (ii) The existence of end-of-pulse tensile waves and its relevance on the overall response (iii) A reduction of 44% in tensile pressure could be obtained by the use of a high density tantalum cladding.

  11. Thermal Evolution Of The Core And Mantle Of Mars: Effects Of A Sequence Of Basin-Forming Impacts

    NASA Astrophysics Data System (ADS)

    Roberts, James; Arkani-Hamed, Jafar

    2015-04-01

    Several giant impact basins have been identified on Mars [1-2]. The youngest of these basins [1] are completely demagnetized [3], indicating that a global magnetic field [4] vanished in the mid-Noachian. Shock heating from the seven largest impacts penetrates below the core-mantle boundary (CMB) [5]. Previous investigations of coupled core cooling and mantle convection [5-6] showed that a single basin-forming impact could halt dynamo activity for 100 My, and that the core would not become fully convective again for nearly 1 Gy after the impact. However, the interval between impacts [1] is shorter than the timescale for dynamo activity to resume following an impact. Sub-sequent impacts may delay this recovery. Here, we expand this investigation into 3D and consider the full sequence of basin-forming impacts large enough to affect the core. Our goal is to obtain a better estimate of the timescale for resumption of dynamo activity. We compute the shock heating due to formation of the seven largest impact basins in the core and mantle using ray-tracing and scaling laws [7-8]. We model 3D mantle convection using CitcomS [9-10], and core cooling with a 1-D parametrization [5]. The temperature is initially adiabatic, with thermal boundary layers (TBL) at the surface and both sides of the CMB. At the time of each impact [1] we introduce a temperature perturbation resulting from shock heating into the core and mantle, and allow the core to stratify [11]. At a given timestep, we fix the mantle temperature and solve the 1D enthalpy equation in the core and lower TBL of the mantle over a time corresponding to a mantle timestep. We update the temperature at the CMB and TBL, and let the mantle convection progress for another timestep. We continue this iteration until the next impact occurs, or until the entire core is again convecting. Only the outermost core is affected by the impact heating. Because the conductivity of the core is higher than that of the mantle, the top of the

  12. Response of Honeycomb Core Sandwich Panel with Minimum Gage GFRP Face-Sheets to Compression Loading After Impact

    NASA Technical Reports Server (NTRS)

    McQuigg, Thomas D.; Kapania, Rakesh K.; Scotti, Stephen J.; Walker, Sandra P.

    2011-01-01

    A compression after impact study has been conducted to determine the residual strength of three sandwich panel constructions with two types of thin glass fiber reinforced polymer face-sheets and two hexagonal honeycomb Nomex core densities. Impact testing is conducted to first determine the characteristics of damage resulting from various impact energy levels. Two modes of failure are found during compression after impact tests with the density of the core precipitating the failure mode present for a given specimen. A finite element analysis is presented for prediction of the residual compressive strength of the impacted specimens. The analysis includes progressive damage modeling in the face-sheets. Preliminary analysis results were similar to the experimental results; however, a higher fidelity core material model is expected to improve the correlation.

  13. Impact of plasma core profiles on MHD stability at tokamak edge pedestal

    NASA Astrophysics Data System (ADS)

    Aiba, N.; Urano, H.

    2014-11-01

    Impact of plasma core profiles on magnetohydrodynamics (MHD) stability at tokamak edge pedestal is investigated numerically to extend an operation regime for small amplitude grassy edge localized mode (ELM). With the hypotheses that pedestal pressure profile can be predicted with the EPED1 model and the trigger of grassy ELM is an ideal ballooning mode, the impacts of plasma poloidal beta and plasma internal inductance on edge MHD stability are investigated, the parameters of which are related to plasma core profiles and are important parameters for grassy ELMy H-modes in JET quasi-double null plasma. The numerical results indicate that a ballooning mode can be destabilized by decreasing poloidal beta and/or internal inductance. In contrast, it is confirmed that pedestal density, which is also an important parameter for realizing grassy ELMy H-mode, can stabilize a ballooning mode. In combination with these trends, it is possible to relax the necessary conditions for grassy ELMy H-mode by adjusting the parameters carefully, though this relaxation destabilizes type-I ELM more easily due to the increase in edge current density.

  14. Episodic specificity induction impacts activity in a core brain network during construction of imagined future experiences

    PubMed Central

    Madore, Kevin P.; Szpunar, Karl K.; Addis, Donna Rose; Schacter, Daniel L.

    2016-01-01

    Recent behavioral work suggests that an episodic specificity induction—brief training in recollecting the details of a past experience—enhances performance on subsequent tasks that rely on episodic retrieval, including imagining future experiences, solving open-ended problems, and thinking creatively. Despite these far-reaching behavioral effects, nothing is known about the neural processes impacted by an episodic specificity induction. Related neuroimaging work has linked episodic retrieval with a core network of brain regions that supports imagining future experiences. We tested the hypothesis that key structures in this network are influenced by the specificity induction. Participants received the specificity induction or one of two control inductions and then generated future events and semantic object comparisons during fMRI scanning. After receiving the specificity induction compared with the control, participants exhibited significantly more activity in several core network regions during the construction of imagined events over object comparisons, including the left anterior hippocampus, right inferior parietal lobule, right posterior cingulate cortex, and right ventral precuneus. Induction-related differences in the episodic detail of imagined events significantly modulated induction-related differences in the construction of imagined events in the left anterior hippocampus and right inferior parietal lobule. Resting-state functional connectivity analyses with hippocampal and inferior parietal lobule seed regions and the rest of the brain also revealed significantly stronger core network coupling following the specificity induction compared with the control. These findings provide evidence that an episodic specificity induction selectively targets episodic processes that are commonly linked to key core network regions, including the hippocampus. PMID:27601666

  15. Episodic specificity induction impacts activity in a core brain network during construction of imagined future experiences.

    PubMed

    Madore, Kevin P; Szpunar, Karl K; Addis, Donna Rose; Schacter, Daniel L

    2016-09-20

    Recent behavioral work suggests that an episodic specificity induction-brief training in recollecting the details of a past experience-enhances performance on subsequent tasks that rely on episodic retrieval, including imagining future experiences, solving open-ended problems, and thinking creatively. Despite these far-reaching behavioral effects, nothing is known about the neural processes impacted by an episodic specificity induction. Related neuroimaging work has linked episodic retrieval with a core network of brain regions that supports imagining future experiences. We tested the hypothesis that key structures in this network are influenced by the specificity induction. Participants received the specificity induction or one of two control inductions and then generated future events and semantic object comparisons during fMRI scanning. After receiving the specificity induction compared with the control, participants exhibited significantly more activity in several core network regions during the construction of imagined events over object comparisons, including the left anterior hippocampus, right inferior parietal lobule, right posterior cingulate cortex, and right ventral precuneus. Induction-related differences in the episodic detail of imagined events significantly modulated induction-related differences in the construction of imagined events in the left anterior hippocampus and right inferior parietal lobule. Resting-state functional connectivity analyses with hippocampal and inferior parietal lobule seed regions and the rest of the brain also revealed significantly stronger core network coupling following the specificity induction compared with the control. These findings provide evidence that an episodic specificity induction selectively targets episodic processes that are commonly linked to key core network regions, including the hippocampus.

  16. Parallel implementation of RX anomaly detection on multi-core processors: impact of data partitioning strategies

    NASA Astrophysics Data System (ADS)

    Molero, Jose M.; Garzón, Ester M.; García, Inmaculada; Plaza, Antonio

    2011-11-01

    Anomaly detection is an important task for remotely sensed hyperspectral data exploitation. One of the most widely used and successful algorithms for anomaly detection in hyperspectral images is the Reed-Xiaoli (RX) algorithm. Despite its wide acceptance and high computational complexity when applied to real hyperspectral scenes, few documented parallel implementations of this algorithm exist, in particular for multi-core processors. The advantage of multi-core platforms over other specialized parallel architectures is that they are a low-power, inexpensive, widely available and well-known technology. A critical issue in the parallel implementation of RX is the sample covariance matrix calculation, which can be approached in global or local fashion. This aspect is crucial for the RX implementation since the consideration of a local or global strategy for the computation of the sample covariance matrix is expected to affect both the scalability of the parallel solution and the anomaly detection results. In this paper, we develop new parallel implementations of the RX in multi-core processors and specifically investigate the impact of different data partitioning strategies when parallelizing its computations. For this purpose, we consider both global and local data partitioning strategies in the spatial domain of the scene, and further analyze their scalability in different multi-core platforms. The numerical effectiveness of the considered solutions is evaluated using receiver operating characteristics (ROC) curves, analyzing their capacity to detect thermal hot spots (anomalies) in hyperspectral data collected by the NASA's Airborne Visible Infra- Red Imaging Spectrometer system over the World Trade Center in New York, five days after the terrorist attacks of September 11th, 2001.

  17. Dietary fat impacts fetal growth and metabolism: uptake of chylomicron remnant core lipids by the placenta.

    PubMed

    Rebholz, Sandra L; Burke, Katie T; Yang, Qing; Tso, Patrick; Woollett, Laura A

    2011-08-01

    The fetus requires significant energy for growth and development. Although glucose is a major source of energy for the fetus, other maternal nutrients also appear to promote growth. Thus, the goal of these studies was to determine whether triglyceride-rich remnants are taken up by the placenta and whether maternal dietary lipids, independently of adiposity, can impact fetal growth. To accomplish our first goal, chylomicron particles were duallly labeled with cholesteryl ester and triglycerides. The placenta took up remnant particles/core lipids at rates greater than adipose tissue and skeletal muscle but less than the liver. Although the placenta expresses apoE receptors, uptake of chylomicron remnants and/or core lipids can occur independently of apoE. To determine the impact of dietary lipid on fetal growth, independent of maternal adiposity, females were fed high-fat diets (HFD) for 1 mo; there was no change in adiposity or leptin levels prior to or during pregnancy of dams fed HFD. Fetal masses were greater in dams fed HFD, and mRNA levels of proteins involved in fatty acid oxidation (CPT I, PPARα), but not glucose oxidation (pyruvate kinase) or other regulatory processes (HNF-4α, LXR), were increased with maternal dietary fat. There was also no change in mRNA levels of proteins involved in placental glucose and fatty acid transport, and GLUT1 protein levels in microvillous membranes were similar in placentas of dams fed either diet. Thus, the ability of the placenta to take up chylomicron remnant core lipids likely contributes to accelerated fetal growth in females fed high fat diets.

  18. Physical properties of the Yaxcopoil-1 deep drill core, Chicxulub impact structure, Mexico

    NASA Astrophysics Data System (ADS)

    Elbra, Tiiu; Pesonen, Lauri J.

    2011-11-01

    The Chicxulub structure in Mexico, one of the largest impact structures on Earth, was formed 65 Ma by a hypervelocity impact that led to the large mass extinction at the K-Pg boundary. The Chicxulub impact structure is well preserved, but is buried beneath a sequence of carbonate sediments and, thus, requires drilling to obtain subsurface information. The Chicxulub Scientific Drilling Program was carried out at Hacienda Yaxcopoil in the framework of the International Continental Scientific Drilling Program in 2001-2002. The structure was cored from 404 m down to 1511 m, through three intervals: 794 m of postimpact Tertiary sediments, a 100 m thick impactite sequence, and 616 m of preimpact Cretaceous rocks thought to represent a suite of megablocks. Physical property investigations show that the various lithologies, including the impactite units and the K-Pg boundary layer, can be characterized by their physical properties, which depend on either changes in fabric or on mineralogical variations. The magnetic properties show mostly dia- or paramagnetic behavior, with the exception of the impactite units that indicate the presence of ferromagnetic, probably hydrothermally deposited magnetite and pyrrhotite. The magnetic fraction contributes mainly to enhanced magnetization in the impactite lithologies and, in this way, to the observed magnetic anomalies. The shape and orientation of the magnetic grains are varied and reflect inhomogeneous fabric development and the influence of impact-related redeposition and hydrothermal activity. The Chicxulub impact occurred at the time of the reverse polarity geomagnetic chron 29R, and this finding is consistent with the age of the K-Pg boundary.

  19. Impact of a Core Ferrule Design on Fracture Resistance of Teeth Restored with Cast Post and Core

    PubMed Central

    Chaaban, Farid

    2016-01-01

    Objectives. To investigate the influence of a contra bevel on the fracture resistance of teeth restored with cast post and core. Materials and Methods. Sixty plastic analogues of an upper incisor were endodontically treated and prepared with 6° internal taper and 2 mm of ferrule in order to receive a cast post and core. The prepared samples were divided into two groups (n = 30); the first group serves as control while the second group was prepared with an external 30° bevel on the buccal and lingual walls. All samples crowned were exposed to a compressive load at 130° to their long axis until fractures occurred. Fracture resistance loads were recorded and failure modes were also observed. Mann-Whitney test was carried out to compare the two groups. Results. Mean failure loads for the groups were, respectively, 1038.69 N (SD ±243.52 N) and 1078.89 N (SD ±352.21 N). Statistically, there was no significant difference between the two groups (P = 0.7675 > 0.05). Conclusion. In the presence of a ferrule and a crown in the anterior teeth, adding a secondary ferrule to the cast post and core will not increase the resistance to fracture. PMID:27419202

  20. Impact of structure and functionality of core polyol in highly functional biobased epoxy resins.

    PubMed

    Pan, Xiao; Webster, Dean C

    2011-09-01

    Highly functional biobased epoxy resins were prepared using dipentaerythritol (DPE), tripentaerythritol (TPE), and sucrose as core polyols that were substituted with epoxidized soybean oil fatty acids, and the impact of structure and functionality of the core polyol on the properties of the macromolecular resins and their epoxy-anhydride thermosets was explored. The chemical structures, functional groups, molecular weights, and compositions of epoxies were characterized using nuclear magnetic resonance (NMR) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI MS). The epoxies were also studied for their bulk viscosity, intrinsic viscosity, and density. Crosslinked with dodecenyl succinic anhydride (DDSA), epoxy-anhydride thermosets were evaluated using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), tensile tests, and tests of coating properties. Epoxidized soybean oil (ESO) was used as a control. Overall, the sucrose-based thermosets exhibited the highest moduli, having the most rigid and ductile performance while maintaining the highest biobased content. DPE/TPE-based thermosets showed modestly better thermosetting performance than the control ESO thermoset.

  1. Human and climate impacts on Holocene fire activity recorded in polar and mountain ice cores

    NASA Astrophysics Data System (ADS)

    Kehrwald, Natalie; Zennaro, Piero; Kirchgeorg, Torben; Li, Quanlian; Wang, Ninglian; Power, Mitchell; Zangrando, Roberta; Gabrielli, Paolo; Thompson, Lonnie; Gambaro, Andrea; Barbante, Carlo

    2014-05-01

    similar to regional charcoal compilations from New Zealand and southeastern Australia. Evidence from Kilimanjaro demonstrates a major increase in fire activity centered around 800-1000 years ago, corresponding to both increased temperatures and aridity as recorded in regional lake cores. This peak in fire activity is an order of magnitude higher than at any other time in the record including the most recent period. Environmental and anthropological studies suggest that upslope human migrations have occurred in response to the warmer, drier conditions. Kilimanjaro is surrounded by flammable savanna vegetation, yet the Muztagh core is located in an especially arid section of the Tibetan Plateau and consistently contains levoglucosan concentrations that are 100 to 1000 times greater than the mean Kilimanjaro flux. These high concentrations and the lack of available fuel suggest that regional rather than local biomass burning may be the source of the fire products. Biomass burning aerosols are a major component of the South Asian Brown Cloud and may influence the composition and concentration of pyrogenic aerosols across the Tibetan Plateau. The relative impact of human activity versus climate change on Holocene biomass burning varies regionally. Combining ice and sediment core data with model output can help place these regional differences into a global context with implications for a warming climate.

  2. THE EVOLUTION AND IMPACTS OF MAGNETOROTATIONAL INSTABILITY IN MAGNETIZED CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Sawai, Hidetomo; Yamada, Shoichi

    2016-02-01

    We carried out two-dimensional axisymmetric MHD simulations of core-collapse supernovae for rapidly rotating magnetized progenitors. By changing both the strength of the magnetic field and the spatial resolution, the evolution of the magnetorotational instability (MRI) and its impacts upon the dynamics are investigated. We found that the MRI greatly amplifies the seed magnetic fields in the regime where the buoyant mode, not the Alfvén mode, plays a primary role in the exponential growth phase. The MRI indeed has a powerful impact on the supernova dynamics. It makes the shock expansion faster and the explosion more energetic, with some models being accompanied by the collimated jet formations. These effects, however, are not made by the magnetic pressure except for the collimated jet formations. The angular momentum transfer induced by the MRI causes the expansion of the heating region, by which the accreting matter gain additional time to be heated by neutrinos. The MRI also drifts low-Y{sub p} matter from deep inside of the core to the heating region, which makes the net neutrino heating rate larger by the reduction of the cooling due to the electron capture. These two effects enhance the efficiency of the neutrino heating, which is found to be the key to boosting the explosion. Indeed, we found that our models explode far more weakly when the net neutrino heating is switched off. The contribution of the neutrino heating to the explosion energy could reach 60% even in the case of strongest magnetic field in the current simulations.

  3. Lithostratigraphic and petrographic analysis of ICDP drill core LB-07A, Bosumtwi impact structure, Ghana

    NASA Astrophysics Data System (ADS)

    Coney, Louise; Gibson, Roger L.; Reimold, Wolf Uwe; Koeberl, Christian

    Lithostratigraphic and petrographic studies of drill core samples from the 545.08 m deep International Continental Scientific Drilling Program (ICDP) borehole LB-07A in the Bosumtwi impact structure revealed two sequences of impactites below the post-impact crater sediments and above coherent basement rock. The upper impactites (333.38-415.67 m depth) comprise an alternating sequence of suevite and lithic impact breccias. The lower impactite sequence (415.67-470.55 m depth) consists essentially of monomict impact breccia formed from meta-graywacke with minor shale, as well as two narrow injections of suevite, which differ from the suevites of the upper impactites in color and intensity of shock metamorphism of the clasts. The basement rock (470.55-545.08 m depth) is composed of lower greenschist-facies metapelites (shale, schist and minor phyllite), meta-graywacke, and minor meta-sandstone, as well as interlaminated quartzite and calcite layers. The basement also contains a number of suevite dikelets that are interpreted as injection veins, as well as a single occurrence of granophyric-textured rock, tentatively interpreted as a hydrothermally altered granitic intrusion likely related to the regional pre-impact granitoid complexes. Impact melt fragments are not as prevalent in LB-07A suevite as in the fallout suevite facies around the northern crater rim; on average, 3.6 vol% of melt fragments is seen in the upper suevites and up to 18 vol% in the lower suevite occurrences. Shock deformation features observed in the suevites and polymict lithic breccias include planar deformation features in quartz (1 to 3 sets), rare diaplectic quartz glass, and very rare diaplectic feldspar glass. Notably, no ballen quartz, which is abundant in the fallout suevites, has been found in the within-crater impact breccias. An overall slight increase in the degree of shock metamorphism occurs with depth in the impactites, but considerably lower shock degrees are seen in the suevites of

  4. Iridium Concentrations and Abundances of Meteoritic Ejecta from the Eltanin Impact in Sediment Cores from Polarstern Expedition ANT XII/4

    NASA Technical Reports Server (NTRS)

    Kyte, Frank T.

    2002-01-01

    The abundances of meteoritic ejecta from the Eltanin asteroid impact have been examined in several sediment cores recovered by the FS Polarstern during expedition ANT XII/4 using elemental concentrations of iridium and weights of coarse ejecta debris. Three cores with well-preserved impact deposits, PS204-1, PS2708-1, and PS2709-1, each contain Ir and ejecta fluences similar to those found in USNS Eltanin core E13-4. Small Ir anomalies and traces of ejecta were found in cores PS2706-1 and PS2710-1, but since these cores lack well-defined deposits, these are considered to be reworked and not representative of the fallout. No evidence of ejecta was found in cores PS2802-1 and PS2705-1. These results confirm earlier speculation that the Eltanin impact resulted in deposits of ejecta with up to 1 gram/sq centimeter of depris over a wide area of the ocean floor. However, there are sill large uncertainties over the actual regional or global extent of this unique sediment deposit.

  5. Superchondritic Sm/Nd ratio of the Earth: Impact of Earth's core formation

    NASA Astrophysics Data System (ADS)

    Bouhifd, M. A.; Boyet, M.; Cartier, C.; Hammouda, T.; Bolfan-Casanova, N.; Devidal, J. L.; Andrault, D.

    2015-03-01

    This study investigates the impact of Earth's core formation on the metal-silicate partitioning of Sm and Nd, two rare-earth elements assumed to be strictly lithophile although they are widely carried by the sulphide phases in reducing material (e.g. enstatite chondrites). The partition coefficients of Sm and Nd (DSm and DNd) between molten CI and EH chondrites model compositions and various Fe-rich alloys (in the Fe-Ni-C-Si-S system) have been determined in a multi-anvil between 3 and 26 GPa at various temperatures between 2073 and 2440 K, and at an oxygen fugacity ranging from 1 to 5 log units below the iron-wüstite (IW) buffer. The chemical compositions of the run products and trace concentrations in Sm and Nd elements were determined using electron microprobe and laser ablation inductively coupled plasma-mass spectrometry. Our results demonstrate the non-fractionation of Sm and Nd during the segregation of the metallic phases: the initial Sm/Nd ratio of about 1 in the starting materials yields precisely the same ratio in the recovered silicate phases after the equilibration with the metal phases at all conditions investigated in this study. In addition, DSm and DNd values range between 10-3 and 10-5 representing a low solubility in the metal. An increase of the partition coefficients is observed with decreasing the oxygen fugacity, or with an increase of S content of the metallic phase at constant oxygen fugacity. Thus, based on the actual Sm and Nd concentrations in the bulk Earth, the core should contain less than 0.4 ppb for Sm and less than 1 ppb for Nd. These estimates are three orders of magnitude lower than what would be required to explain the reported 142Nd excess in terrestrial samples relative to the mean chondritic value, using the core as a Sm-Nd complementary reservoir. In other words, the core formation processes cannot be responsible for the increase of the Sm/Nd ratio in the mantle early in Earth history.

  6. Evidence for Multiple Holocene Marine Impact Events: Ejecta in a Bog Core

    NASA Astrophysics Data System (ADS)

    Abbott, D. H.; Courty, M.; Breger, D.; Costa, S.; Gerard-Little, P.; Burckle, L.; Pekar, S.

    2006-12-01

    In a core from Tamarack Pond (a former bog) in the Hudson Highlands of New York, we found two layers containing marine microfossils. Because carbon rich sediments can be bioturbated over 20 cm depths, we give the layer thicknesses as 20 cm. The first layer is at 332-354 cm depth. It contains a radiolarian with a splashed on coating of Fe-Cr-Ni metal. It also contains a benthonic foraminiferal fossil. The second layer is at 432-454 cm depth. The second layer contains a degraded radiolarian fossil, a silicate with a splashed on coating of Fe-Cr-Ni metal, a carbon rich spherule containing Fe-Cr-Ni metal, and a grain of titanomagnetite with multiple craters. It also contains organic matter with Sn in it. As Tamarack Pond is quite far from the ocean, the marine fossils in the cores are unlikely to be windblown debris of Holocene age. A benthonic foraminifera is particularly unlikely to be blown by the wind. This conclusion is strengthened by the observation that the splashed on coating of Fe-Cr-Ni metal occurs in chondritic relative abundances with Fe>Cr>Ni. In grains with a thick layer of splashed metal, the Ni is sufficiently abundant to produce 3 distinct Ni peaks in the X-ray analysis. Such a high abundance of Ni coupled with chondritic relative abundances suggests that the Fe-Cr- Ni splash is derived from the vaporization of an extraterrestrial impactor. If we assume that the sedimentation rate of the Tamarack Pond core is the same as that of a previously dated core from nearby Sutherland Pond, the two layers have an uncorrected C-14 age of around 900-1200 B.C. for the layer at 332-354 cm and 2100 to 2400 B.C. for the layer at 432-454 cm. Both ages have a rough correspondence with times of climate downturn recorded in tree ring data (1159 and 2354 B.C.). These climate downturns cannot be explained by volcanic eruptions and are proposed to be cosmogenic in origin[1]. The older layer also corresponds in components to a previously studied circa 2350 B.C. impact ejecta

  7. Evidence from an Ice Core of a Large Impact Circa 1443 A.D.

    NASA Astrophysics Data System (ADS)

    Abbott, D.; Biscaye, P.; Cole-Dai, J.; Breger, D.

    2005-12-01

    Published data on melt water from the Siple Dome ice core show distinct anomalies at 1443.16 A.D. The Ca value is 111 ppb, over 9 times the next highest Ca value between 850-1760 A.D. The K value is 20 ppb, about 1.4 times the next highest K value. The Ca anomaly may be due to partial dissolution of CaCO3 microfossils from the 24 km Mahuika bolide impact crater on the southern New Zealand shelf. Deep-sea samples of the Mahuika ejecta layer contain >98% carbonate microfossils. The Mahuika impact may have produced tsunami runups of 130 meters in Jervis Bay, Australia. The Australian megatsunami deposits date to 1450±50 A.D. We analyzed the melt water from 8 ice-core samples from the West Antarctic Siple Dome ice core that date from 1440-1448 A.D. The 1443 A.D. level contained a peak in K of 53 ppb as compared to a background of ~6-7 ppb. Ca was high at 26 ppb but this is not as pronounced as reported earlier. We extracted solid material from the melt water. Except for the 1443 A.D. horizon and one fractured grain at the 1442 A.D. level, most samples were barren except for typical dust. At the 1443 A.D. level, we found 5 carbonate microfossils (coccoliths?) from 5 to 20 microns across. Two were round and solid. One microfossil appeared either caught during mitosis or broken during deformation and elongation. Another carbonate microfossil was unbroken, but appeared deformed into a square. We found a Cu grain with a small amount of oxygen. It is most likely a grain of native copper with an oxidized surface. Deformed microfossils and native minerals are both characteristic of bolide impacts. We also found many microcrystalline magnetite cubes, with an average crystal size of 0.3 microns or less. The high magnetic susceptibility of impact ejacta layers is caused by microcrystalline magnetite. We found a grain of conchoidally fractured feldspar ~15 microns long. A semi-quantitive EDAX analysis found 21% Si, 55% O, 9% Al, 5% Na, 3% K, 2% Fe, and 1% Ca (atomic %), well

  8. Initial Results on the Extraterrestrial Component of New Sediment Cores Containing Deposits of the Eltanin Impact Event

    NASA Technical Reports Server (NTRS)

    Kyte, Frank T.; Gersonde, Rainer

    2003-01-01

    Background The impact of the Eltanin asteroid into the Bellingshausen Sea (2.15 Ma) is the only known impact in a deep-ocean (approx. 5 km) basin. In 1995, Polarstern expedition ANT XII/4 made the first geological survey of the suspected impact region. Three sediment cores sampled around the San Martin seamounts (approx. 57.5 S, 91 W) contained well-preserved impact deposits. Sediments of Eocene age and younger were ripped up and redeposited by the impact. The depositional sequence produced by the impact has three units: a chaotic assemblage of sediment fragments up to 50 cm, followed by laminated sands deposited as a turbulent flow, and finally silts and clays that accumulated from dispersed sediments in the water column. The meteoritic impact ejecta, which is composed of shock-melted asteroidal materials and unmelted meteorites, settled through the water column and concentrated near the top of the laminated sands.

  9. Impact of high ytterbium(III) concentration in the shell on upconversion luminescence of core-shell nanocrystals.

    PubMed

    Lei, Lei; Chen, Daqin; Zhu, Wenjuan; Xu, Ju; Wang, Yuansheng

    2014-10-01

    After coating 20 Yb/2 Er:NaGdF4 core nanocrystals with a NaYbF4 shell, upconversion emission of the rare earth ions weakens. So far, the exact reason for this phenomenon is still unclear due to lack of the direct evidence. In this report, a core@shell@shell sandwich-like structure is designed and fabricated to investigate this phenomenon. We find that high Yb(3+) concentration in the shell has mainly two adverse impacts: it promotes not only the deleterious back energy transfer from Er(3+) in the core to Yb(3+) in the shell but also the energy transfer from Yb(3+) in the core to Yb(3+) in the shell. To obtain nanocrystals with high upconversion efficency, appropriate Yb(3+) concentration should be introduced into the shell or the transition layer.

  10. Does length of prostate biopsy cores have an impact on diagnosis of prostate cancer?

    PubMed Central

    Ergün, Müslüm; İslamoğlu, Ekrem; Yalçınkaya, Soner; Tokgöz, Hüsnü; Savaş, Murat

    2016-01-01

    Objective To investigate whether core length is a significant biopsy parameter in the detection of prostate cancer. Material and methods We retrospectively analyzed pathology reports of the specimens of 188 patients diagnosed with prostate cancer who had undergone initial transrectal ultrasound (TRUS) guided prostate biopsy, and compared biopsy core lengths of the patients with, and without prostate cancer. The biopsy specimens of prostate cancer patients were divided into 3 groups according to core length, and the data obtained were compared (Group 1; total core length <10 mm, Group 2; total core length 10 mm–19 mm, and Group 3; total core length >20 mm). Biopsy core lengths of the patients diagnosed as prostate cancer, and benign prostatic hyperplasia were compared, and a certain cut-off value for core length with optimal diagnostic sensitivity and specificity for prostate cancer was calculated. Results Mean age, PSA and total length of cores were 65.08±7.41 years, 9.82±6.34 ng/mL and 11.2±0.2 mm, respectively. Assessment of biopsy core lengths showed that cores with cancer (n=993, median length 12.5 mm) were significantly longer than benign cores (n=1185, median length=11.3 mm) (p<0.001). Core length analysis yielded 12 mm cores have an optimal sensitivity (41.9%) and specificity (62%) for detection of cancer (odds ratio: 1.08). Conclusion Biopsy core length is one of the most important parameter that determines the quality of biopsy and detection of prostate cancer. A median sample length of 12 mm is ideal lower limit for cancer detection, and biopsy procedures which yield shorter biopsy cores should be repeated. PMID:27635285

  11. Critical review of the impact of core stability on upper extremity athletic injury and performance

    PubMed Central

    Silfies, Sheri P.; Ebaugh, David; Pontillo, Marisa; Butowicz, Courtney M.

    2015-01-01

    BACKGROUND: Programs designed to prevent or rehabilitate athletic injuries or improve athletic performance frequently focus on core stability. This approach is based upon the theory that poor core stability increases the risk of poor performance and/or injury. Despite the widespread use of core stability training amongst athletes, the question of whether or not sufficient evidence exists to support this practice remains to be answered. OBJECTIVES: 1) Open a dialogue on the definition and components of core stability. 2) Provide an overview of current science linking core stability to musculoskeletal injuries of the upper extremity. 3) Provide an overview of evidence for the association between core stability and athletic performance. DISCUSSION: Core stability is the ability to control the position and movement of the trunk for optimal production, transfer, and control of forces to and from the upper and lower extremities during functional activities. Muscle capacity and neuromuscular control are critical components of core stability. A limited body of evidence provides some support for a link between core stability and upper extremity injuries amongst athletes who participate in baseball, football, or swimming. Likewise, few studies exist to support a relationship between core stability and athletic performance. CONCLUSIONS: A limited body of evidence exists to support the use of core stability training in injury prevention or performance enhancement programs for athletes. Clearly more research is needed to inform decision making when it comes to inclusion or emphasis of core training when designing injury prevention and rehabilitation programs for athletes. PMID:26537806

  12. Impact of Pin-by-Pin Thermal-Hydraulic Feedback Modeling on Steady-State Core Characteristics

    SciTech Connect

    Yamamoto, Akio; Ikeno, Tsutomu

    2005-02-15

    In this paper, the effect of a pin-by-pin thermal-hydraulic feedback treatment on the core characteristics at a steady-state condition is investigated using a three-dimensional fine-mesh core calculation code. Currently, advanced nodal codes treat the inside of an assembly as homogeneous, and the temperature distribution inside a node is usually ignored. Namely, the fuel temperature is estimated from the assembly average power density, and the moderator temperature is calculated from the nodewise closed-channel model. However, the validity of a flat temperature distribution inside a node has not yet been investigated, because a three-dimensional pin-by-pin whole-core calculation must be done for comparison. A three-dimensional pin-by-pin nodal-transport code for a pressurized water reactor (PWR) core analysis, SCOPE2, was used in this study since it can directly treat the pin-by-pin feedback effect. A whole-core subchannel analysis code was developed to enhance the thermal-hydraulic capability of SCOPE2. The pin-by-pin feedback models for fuel and moderator temperature were established, and their impact on the core characteristics was investigated in a 3 x 3 multiassembly and the whole PWR core geometries. The calculations showed that modeling of the pin-by-pin temperature distribution revealed a negligible effect on core reactivity and only a slight impact on the radial peaking factor. The difference in the radial peaking factor that is exposed by the pin-by-pin temperature modeling is less than 0.005 in the test calculations.

  13. Initial Results on the Meteoritic Component of new Sediment Cores Containing Deposits of the Eltanin Impact Event

    NASA Technical Reports Server (NTRS)

    Kyte, Frank T.; Gersonde, Rainer; Kuhn, Gerhard

    2002-01-01

    The late Pliocene impact of the Eltanin asteroid is the only known asteroid impact in a deep- ocean (-5 km) basin . This was first discovered in 1981 as an Ir anomaly in sediment cores collected by the USNS Eltanin in 1965. In 1995, Polarstern expedition ANT XII/4 made the first geological survey of the suspected impact region. Three sediment cores sampled around the San Martin seamounts (approx. 57.5 S, 91 W) contained well-preserved impact deposits that include disturbed ocean sediments and meteoritic impact ejecta. The latter is composed of shock-melted asteroidal materials and unmelted meteorites. In 2001, the FS Polarstern returned to the impact area during expedition ANT XVIIU5a. At least 16 cores were recovered that contain ejecta deposits. These cores and geophysical data from the expedition can be used to map the effects of the impact over a region of about 80,000 square km. To date we have measured Ir concentrations in sediments from seven of the new cores and preliminary data should be available for a few more by the time of the meeting. Our initial interpretation of these data is that there is a region in the vicinity of the San Martin Seamounts comprising at least 20,000 square km in which the average amount of meteoritic material deposited was more than 1 g per square cm. This alone is enough material to support a 500 m asteroid. Beyond this is a region of about 60,000 square km, mostly to the north and west, where the amount of ejecta probably averages about 0.2 g per square cm. Another 400 km to the east, USNS Eltanin core E10-2 has about 0.05 g per square cm, so we know that ejecta probably occurs across more than a million square km of ocean floor. A key to future exploration of this impact is to find evidence of the ejecta at more sites distant from the seamounts. We currently have almost no data from regions to the west or south of the San Martin seamounts.

  14. Sediment cores from kettle holes in NE Germany reveal recent impacts of agriculture.

    PubMed

    Kleeberg, Andreas; Neyen, Marielle; Schkade, Uwe-Karsten; Kalettka, Thomas; Lischeid, Gunnar

    2016-04-01

    Glacial kettle holes in young moraine regions receive abundant terrigenous material from their closed catchments. Core chronology and sediment accumulation were determined for two semi-permanent kettle holes, designated RG and KR, on arable land close to the villages of Rittgarten and Kraatz, respectively, in Uckermark, NE Germany. Core dating ((210)Pb, (137)Cs) revealed variable sediment accretion rates through time (RG 0.4-23.1 mm a(-1); KR 0.2-35.5 mm a(-1)), with periods of high accumulation corresponding to periods of intensive agricultural activity and consequent erosional inputs from catchments. Sediment composition (C, N, P, S, K, Ca, Fe, Mn, Zn, Cu, Mo, Pb, Cd, Zr) was used to determine sediment source and input processes. At RG, annual P input increased from 0.65 kg ha(-1) in the early nineteenth century to 1.67 kg ha(-1) by 2013. At KR, P input increased from 0.6 to 4.1 kg ha(-1) over the last century. There was a concurrent increase in Fe input in both water bodies. Thus, Fe/P ratios showed no temporal trend and did not differ between RG (18.5) and KR (18.4), indicating similar P mobility. At RG, the S/Fe ratio increased from 0.4 to 2.3, indicating more iron sulphides and thus higher P availability, coinciding with high coverage of duckweed (Spirodela polyrhiza (L.)) and soft hornwort (Ceratophyllum submersum L.). At KR, however, this ratio remained low and relatively unchanged (0.3 ± 0.4), indicating more efficient Fe-P binding and lower hydrophyte productivity. Trends in sediment composition indicate a shift towards eutrophication in both kettle holes, but with differences in timing and magnitude. Other morphologically similar kettle holes in NE Germany that are prone to erosion could have been similarly impacted but may differ in the extent of sediment infilling and degradation of their ecological functions.

  15. Impacts of rotation on three-dimensional hydrodynamics of core-collapse supernovae

    SciTech Connect

    Nakamura, Ko; Kuroda, Takami; Kotake, Kei; Takiwaki, Tomoya

    2014-09-20

    We perform a series of simplified numerical experiments to explore how rotation impacts the three-dimensional (3D) hydrodynamics of core-collapse supernovae. For our systematic study, we employ a light-bulb scheme to trigger explosions and a three-flavor neutrino leakage scheme to treat deleptonization effects and neutrino losses from the proto-neutron-star interior. Using a 15 M {sub ☉} progenitor, we compute 30 models in 3D with a wide variety of initial angular momentum and light-bulb neutrino luminosity. We find that the rotation can help the onset of neutrino-driven explosions for the models in which the initial angular momentum is matched to that obtained in recent stellar evolutionary calculations (∼0.3-3 rad s{sup –1} at the center). For the models with larger initial angular momentum, the shock surface deforms to be more oblate due to larger centrifugal force. This not only makes the gain region more concentrated around the equatorial plane, but also makes the mass larger in the gain region. As a result, buoyant bubbles tend to be coherently formed and rise in the equatorial region, which pushes the revived shock toward ever larger radii until a global explosion is triggered. We find that these are the main reasons that the preferred direction of the explosion in 3D rotating models is often perpendicular to the spin axis, which is in sharp contrast to the polar explosions around the axis that were obtained in previous two-dimensional simulations.

  16. Core structure and surface functionalization of carbon nanomaterials alter impacts to daphnid mortality, reproduction, and growth: acute assays do not predict chronic exposure impacts.

    PubMed

    Arndt, Devrah A; Moua, Maika; Chen, Jian; Klaper, Rebecca D

    2013-08-20

    There are currently over ninety products incorporating carbon nanomaterials (CNMs) on the market today for a variety of applications. Modifications in core structure and surface chemistry of manufactured nanomaterials are used to optimize nanomaterials for specific uses. However, there is a notable lack of information on how core structure and surface chemistry may alter toxicity in low-level, chronic exposures. This paper examines the effects of twelve CNMs that differ in their core structure and surface chemistry to Daphnia magna over a 21-day chronic exposure. Overall, nanomaterials with a carbon nanotube core were more toxic to daphnids than fullerenes, with the one exception of fullerenes with a gamma-cyclodextrin surface chemistry. Acute mortality was not a good predictor of chronic effects as none of the CNMs induced toxicity at tested concentrations after 48 h, yet chronic assays indicated significant differences in mortality, reproduction, and growth realized after 21 days. Our results indicate that (1) acute exposure assays do not accurately describe the impact of CNMs to biological systems, (2) chronic exposures provide valuable information that indicates the potential for different modes of action for nanomaterials of differing chemistries, and (3) core structure and surface chemistry both influence particle toxicity.

  17. Stellar electron capture rates on neutron-rich nuclei and their impact on stellar core collapse

    NASA Astrophysics Data System (ADS)

    Raduta, Ad. R.; Gulminelli, F.; Oertel, M.

    2017-02-01

    During the late stages of gravitational core-collapse of massive stars, extreme isospin asymmetries are reached within the core. Due to the lack of microscopic calculations of electron-capture (EC) rates for all relevant nuclei, in general simple analytic parametrizations are employed. We study here several extensions of these parametrizations, allowing for a temperature, electron density, and isospin dependence as well as for odd-even effects. The latter extra degrees of freedom considerably improve the agreement with large-scale microscopic rate calculations. We find, in particular, that the isospin dependence leads to a significant reduction of the global EC rates during core collapse with respect to fiducial results, where rates optimized on calculations of stable f p -shell nuclei are used. Our results indicate that systematic microscopic calculations and experimental measurements in the N ≈50 neutron-rich region are desirable for realistic simulations of the core collapse.

  18. Novel magnetic core materials impact modelling and analysis for minimization of RF heating loss

    NASA Astrophysics Data System (ADS)

    Ghosh, Bablu Kumar; Mohamad, Khairul Anuar; Saad, Ismail

    2016-02-01

    The eddy current that exists in RF transformer/inductor leads to generation of noise/heat in the circuit and ultimately reduces efficiency in RF system. Eddy current is generated in the magnetic core of the inductor/transformer largely determine the power loss for power transferring process. The losses for high-frequency magnetic components are complicated due to both the eddy current variation in magnetic core and copper windings reactance variation with frequency. Core materials permeability and permittivity are also related to variation of such losses those linked to the operating frequency. This paper will discuss mainly the selection of novel magnetic core materials for minimization of eddy power loss by using the approach of empirical equation and impedance plane simulation software TEDDY V1.2. By varying the operating frequency from 100 kHz to 1GHz and magnetic flux density from 0 to 2 Tesla, the eddy power loss is evaluated in our study. The Nano crystalline core material is found to be the best core material due to its low eddy power loss at low conductivity for optimum band of frequency application.

  19. Impact of surface roughness of gypsum materials on adaptation of zirconia cores

    PubMed Central

    Kim, Ki-Baek; Kim, Sa-Hak

    2015-01-01

    PURPOSE The present study investigated the influences of various gypsum materials on the precision of fit of CAD/CAM-fabricated prostheses and analyzed their correlation with surface roughness. MATERIALS AND METHODS The master model of the mandibular right first molar was replicated, and four experimental groups based on two types of Type IV stone (GC Fujirock EP, Die keen) and two types of scannable stone (Aesthetic-Basegold, Everest Rock) were created to include a total of 40 specimens, 10 in each group. The surface roughness of the working models for the respective experimental groups was measured. Once the zirconia cores had been fabricated, the marginal and internal fits were measured with a digital microscope using the silicone replica technique. The mean and standard deviation of the respective points of measurement were computed and analyzed through the one-way ANOVA and Tukey's HSD test. The correlation between surface roughness and the precision of fit of the zirconia core was analyzed using the Pearson correlation analysis (α=.05). RESULTS The zirconia cores fabricated from the scannable stone working models exhibited a superior precision of fit as compared to those fabricated from the Type IV stone working models. The correlation analysis results showed a clear positive correlation between surface roughness and the precision of fit of zirconia cores in all of the experimental groups (P<.05). CONCLUSION The results confirmed that the surface roughness of dental working models has a decisive influence on the precision of fit of zirconia cores. PMID:26140171

  20. Integrated sequence stratigraphy of the postimpact sediments from the Eyreville core holes, Chesapeake Bay impact structure inner basin

    USGS Publications Warehouse

    Browning, J.V.; Miller, K.G.; McLaughlin, P.P.; Edwards, L.E.; Kulpecz, A.A.; Powars, D.S.; Wade, B.S.; Feigenson, M.D.; Wright, J.D.

    2009-01-01

    The Eyreville core holes provide the first continuously cored record of postimpact sequences from within the deepest part of the central Chesapeake Bay impact crater. We analyzed the upper Eocene to Pliocene postimpact sediments from the Eyreville A and C core holes for lithology (semiquantitative measurements of grain size and composition), sequence stratigraphy, and chronostratigraphy. Age is based primarily on Sr isotope stratigraphy supplemented by biostratigraphy (dinocysts, nannofossils, and planktonic foraminifers); age resolution is approximately ??0.5 Ma for early Miocene sequences and approximately ??1.0 Ma for younger and older sequences. Eocene-lower Miocene sequences are subtle, upper middle to lower upper Miocene sequences are more clearly distinguished, and upper Miocene- Pliocene sequences display a distinct facies pattern within sequences. We recognize two upper Eocene, two Oligocene, nine Miocene, three Pliocene, and one Pleistocene sequence and correlate them with those in New Jersey and Delaware. The upper Eocene through Pleistocene strata at Eyreville record changes from: (1) rapidly deposited, extremely fi ne-grained Eocene strata that probably represent two sequences deposited in a deep (>200 m) basin; to (2) highly dissected Oligocene (two very thin sequences) to lower Miocene (three thin sequences) with a long hiatus; to (3) a thick, rapidly deposited (43-73 m/Ma), very fi ne-grained, biosiliceous middle Miocene (16.5-14 Ma) section divided into three sequences (V5-V3) deposited in middle neritic paleoenvironments; to (4) a 4.5-Ma-long hiatus (12.8-8.3 Ma); to (5) sandy, shelly upper Miocene to Pliocene strata (8.3-2.0 Ma) divided into six sequences deposited in shelf and shoreface environments; and, last, to (6) a sandy middle Pleistocene paralic sequence (~400 ka). The Eyreville cores thus record the fi lling of a deep impact-generated basin where the timing of sequence boundaries is heavily infl uenced by eustasy. ?? 2009 The Geological

  1. The Principalship: Essential Core Competencies for Instructional Leadership and Its Impact on School Climate

    ERIC Educational Resources Information Center

    Ross, Dorrell J.; Cozzens, Jeffry A.

    2016-01-01

    The purpose of this quantitative study was to investigate teachers' perceptions of principals' leadership behaviors influencing the schools' climate according to Green's (2010) ideologies of the 13 core competencies within the four dimensions of principal leadership. Data from the "Leadership Behavior Inventory" (Green, 2014) suggest 314…

  2. The Intellectual Foundations of Education: Core Journals and Their Impacts on Scholarship and Practice

    ERIC Educational Resources Information Center

    Goodyear, Rodney K.; Brewer, Dominic J.; Gallagher, Karen Symms; Tracey, Terence J. G.; Claiborn, Charles D.; Lichtenberg, James W.; Wampold, Bruce E.

    2009-01-01

    Academic journals are the primary mode of communication among researchers, and they play a central role in the creation, diffusion, and use of knowledge. This article updates previous attempts to identify a core set of journals that most education scholars would acknowledge as consequential sources. On the basis of nominations from a panel of…

  3. Impact of the Common Core on Social-Emotional Learning Initiatives with Diverse Students

    ERIC Educational Resources Information Center

    Gubi, Aaron A.; Bocanegra, Joel O.

    2015-01-01

    A leading challenge for educators in the twenty-first century is to effectively promote academic outcomes among diverse student learners. Indeed, students from diverse and/or minority ethno-cultural, linguistic, and socioeconomic backgrounds are much more likely to experience academic difficulties and dropout. The Common Core initiative has been…

  4. The Impact of iCivics on Students' Core Civic Knowledge

    ERIC Educational Resources Information Center

    LeCompte, Karon; Moore, Brandon; Blevins, Brooke

    2011-01-01

    iCivics, a free online, civics education program created by Supreme Court Justice Sandra Day O'Connor, is aligned to state and national standards to teach core civics content. The research question for this study is: Does spending at least 30 minutes on the iCivics interactive web site 2 times per week improve student scores on a civics test? A…

  5. Use of Relativistic Effective Core Potentials in the Calculation of Electron-Impact Ionization Cross Sections

    NASA Technical Reports Server (NTRS)

    Huo, Winifred M.; Kim, Yong-Ki

    1999-01-01

    Based on the Binary-Encounter-Bethe (BEB) model, the advantage of using relativistic effective core potentials (RECP) in the calculation of total ionization cross sections of heavy atoms or molecules containing heavy atoms is discussed. Numerical examples for Ar, Kr, Xe, and WF6 are presented.

  6. The Impact of Feedback During Massive Star Formation by Core Accretion

    NASA Astrophysics Data System (ADS)

    Tanaka, Kei E. I.; Tan, Jonathan C.; Zhang, Yichen

    2017-01-01

    We study feedback during massive star formation using semi-analytic methods, considering the effects of disk winds, radiation pressure, photoevaporation, and stellar winds, while following protostellar evolution in collapsing massive gas cores. We find that disk winds are the dominant feedback mechanism setting star formation efficiencies (SFEs) from initial cores of ∼0.3–0.5. However, radiation pressure is also significant to widen the outflow cavity causing reductions of SFE compared to the disk-wind only case, especially for > 100 {M}ȯ star formation at clump mass surface densities {{{Σ }}}{cl}≲ 0.3 {{g}} {{cm}}-2. Photoevaporation is of relatively minor importance due to dust attenuation of ionizing photons. Stellar winds have even smaller effects during the accretion stage. For core masses {M}c≃ 10–1000 {M}ȯ and {{{Σ }}}{cl}≃ 0.1–3 {{g}} {{cm}}-2, we find the overall SFE to be {\\bar{\\varepsilon }}* f=0.31{({R}c/0.1{pc})}-0.39, potentially a useful sub-grid star formation model in simulations that can resolve pre-stellar core radii, {R}c=0.057{({M}c/60{M}ȯ )}1/2{({{{Σ }}}{cl}/{{g}}{{cm}}-2)}-1/2 {pc}. The decline of SFE with Mc is gradual with no evidence for a maximum stellar-mass set by feedback processes up to stellar masses of {m}* ∼ 300 {M}ȯ . We thus conclude that the observed truncation of the high-mass end of the IMF is shaped mostly by the pre-stellar core mass function or internal stellar processes. To form massive stars with the observed maximum masses of ∼150–300{M}ȯ , initial core masses need to be ≳ 500–1000 {M}ȯ . We also apply our feedback model to zero-metallicity primordial star formation, showing that, in the absence of dust, photoevaporation staunches accretion at ∼ 50 {M}ȯ . Our model implies radiative feedback is most significant at metallicities ∼ {10}-2{Z}ȯ , since both radiation pressure and photoevaporation are effective in this regime.

  7. Drill core LB-08A, Bosumtwi impact structure, Ghana: Petrographic and shock metamorphic studies of material from the central uplift

    NASA Astrophysics Data System (ADS)

    Ferrière, Ludovic; Koeberl, Christian; Reimold, Wolf Uwe

    During a recent drilling project sponsored by the International Continental Scientific Drilling Progam (ICDP), two boreholes (LB-07A and LB-08A) were drilled into the crater fill of the Bosumtwi impact structure and the underlying basement, into the deep crater moat and the outer flank of the central uplift, respectively. The Bosumtwi impact structure in Ghana (West Africa), which is 10.5 km in diameter and 1.07 Myr old, is largely filled by Lake Bosumtwi. Here we present the lithostratigraphy of drill core LB-08A (recovered between 235.6 and 451.33 m depth below lake level) as well as the first mineralogical and petrographic observations of samples from this core. This drill core consists of approximately 25 m of polymict, clast-supported lithic breccia intercalated with suevite, which overlies fractured/brecciated metasediment that displays a large variation in lithology and grain size. The lithologies present in the central uplift are metasediments composed dominantly of fine-grained to gritty meta-graywacke, phyllite, and slate, as well as suevite and polymict lithic impact breccia. The suevites, principally present between 235.6 and 240.5 m and between 257.6 and 262.2 m, display a fine-grained fragmental matrix (about 39 to 45 vol%) and a variety of lithic and mineral clasts that include meta-graywacke, phyllite, slate, quartzite, carbon-rich organic shale, and calcite, as well as melt particles, fractured quartz, unshocked quartz, unshocked feldspar, quartz with planar deformation features (PDFs), diaplectic quartz glass, mica, epidote, sphene, and opaque minerals). The crater-fill suevite contains calcite clasts but no granite clasts, in contrast to suevite from outside the northern crater rim. The presence of melt particles in suevite samples from the uppermost 25 meters of the core and in suevite dikelets in the basement is an indicator of shock pressures exceeding 45 GPa. Quartz grains present in suevite and polymict lithic impact breccia abundantly

  8. Impact of fiber core diameter on dispersion and multiplexing in multimode-fiber links.

    PubMed

    Appaiah, Kumar; Vishwanath, Sriram; Bank, Seth R

    2014-07-14

    Large-core silica multimode fibers, whose core diameters are generally 50 μm or 62.5 μm, form the bulk of short and medium haul optical fiber links in existence today, owing to their low cost and ease of deployment. However, modal dispersion significantly limits the maximum data rates that they support. Recently, the ability to multiplex several streams of data through optical fibers has spawned the development of few-mode multimode fibers. These fibers possess the low-dispersion characteristics of single-mode fibers and the ability to multiplex several data streams using multiple-input multiple-output (MIMO) techniques and mode-specific filtering to increase data rates. While fibers with larger core diameters possess a larger number of spatial modes, they do not support data rates as high as few-mode fibers. In this paper, we describe a simulation based approach to characterize the tradeoffs between fiber diameter, achievable data rates and alignment tolerances of coherent links that employ graded-index multimode fibers (MMFs) of various dimensions, using the information theoretic outage capacity as the metric. The simulations used fibers' intermodal coupling characteristics to measure its multiplexing abilities and dispersion limitations with mode-specific filters and launch and detection spatial filter arrays. The simulations indicate that the bandwidth-length product achievable over few-mode fibers with MIMO techniques can exceed 250 Gb/s-km, while heavy mode spreading and limited mode selectivity limits the bandwidth-length product to under 25 Gb/s-km in fibers core diameters larger than 50 μm.

  9. The impact of poloidal asymmetries on tungsten transport in the core of JET H-mode plasmas

    SciTech Connect

    Angioni, C.; Pütterich, T.; Bilato, R.; Casson, F. J.; Giroud, C.; Mantica, P.; Helander, P.

    2015-05-15

    Recent progress in the understanding and prediction of the tungsten behaviour in the core of JET H-mode plasmas with ITER-like wall is presented. Particular emphasis is given to the impact of poloidal asymmetries of the impurity density. In particular, it is shown that the predicted reduction of temperature screening induced by the presence of low field side localization of the tungsten density produced by the centrifugal force is consistent with the observed tungsten behaviour in a JET discharge in H-mode baseline scenario. This provides first evidence of the role of poloidal asymmetries in reducing the strength of temperature screening. The main differences between plasma parameters in JET baseline and hybrid scenario discharges which affect the impact of poloidally asymmetric density on the tungsten radial transport are identified. This allows the conditions by which tungsten accumulation can be avoided to be more precisely defined.

  10. Down-core changes in molluscan death assemblages at Panzano Bay, an impacted area in the northern Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Haselmair, Alexandra; Gallmetzer, Ivo; Stachowitsch, Michael; Tomasovych, Adam; Zuschin, Martin

    2016-04-01

    We use a historical ecology approach to shed light on the environmental history of the northern Adriatic Sea over the last hundreds to thousands of years. We focus on down-core changes in molluscan death assemblages, which serve as proxies for ecological shifts over time. The northern Adriatic Sea is particularly suited to study ecosystem modification under human pressure because it is among the most degraded marine ecosystems worldwide. We chose a sampling station in Panzano Bay, close the Isonzo River mouth and not far from the major industrial harbours of Trieste (Italy) and Koper (Slovenia), and traced down-core changes in molluscan community structure in correlation to major anthropogenic impacts that occurred here during the last centuries. Five sediment cores (1.5 m in length and diameters of 90 and 160 mm) were taken at a water depth of 12 m. We analysed grain size composition, the concentration of heavy metals and organic pollutants, and radiometrically dated the sediment using 210Pb. Furthermore, we dated shells of the abundant bivalve species Corbula gibba using 14C calibrated amino acid-racemisation (AAR). The whole molluscan community in the cores was analysed for species composition, abundance, taxonomic similarity, evidence for ecological interactions (i.e., frequencies of drilling predation) and taphonomic conditions of shells. The granulometric analysis shows that silt and clay dominate equally throughout the cores. Radiometric sediment dating revealed an average sedimentation rate of 2.5 mm/yr during the last 120 years. Shell dating points to a comparable overall core age, with only a few shell specimens being older than 500 years in the deepest core layer. In total, 10,452 mollusc individuals were analysed and 104 species identified. The most abundant bivalve species are Kurtiella bidentata, Corbula gibba and Abra nitida. Turritella communis and Nassarius pygmaeus are the most frequent gastropod species. Down-core changes in species composition

  11. Projected Impact of the ICD-10-CM/PCS Conversion on Longitudinal Data and the Joint Commission Core Measures

    PubMed Central

    Fenton, Susan H.; Benigni, Mary Sue

    2014-01-01

    The transition from ICD-9-CM to ICD-10-CM/PCS is expected to result in longitudinal data discontinuities, as occurred with cause-of-death in 1999. The General Equivalence Maps (GEMs), while useful for suggesting potential maps do not provide guidance regarding the frequency of any matches. Longitudinal data comparisons can only be reliable if they use comparability ratios or factors which have been calculated using records coded in both classification systems. This study utilized 3,969 de-identified dually coded records to examine raw comparability ratios, as well as the comparability ratios between the Joint Commission Core Measures. The raw comparability factor results range from 16.216 for Nicotine dependence, unspecified, uncomplicated to 118.009 for Chronic obstructive pulmonary disease, unspecified. The Joint Commission Core Measure comparability factor results range from 27.15 for Acute Respiratory Failure to 130.16 for Acute Myocardial Infarction. These results indicate significant differences in comparability between ICD-9-CM and ICD-10-CM code assignment, including when the codes are used for external reporting such as the Joint Commission Core Measures. To prevent errors in decision-making and reporting, all stakeholders relying on longitudinal data for measure reporting and other purposes should investigate the impact of the conversion on their data. PMID:25214824

  12. Projected impact of the ICD-10-CM/PCS conversion on longitudinal data and the Joint Commission Core Measures.

    PubMed

    Fenton, Susan H; Benigni, Mary Sue

    2014-01-01

    The transition from ICD-9-CM to ICD-10-CM/PCS is expected to result in longitudinal data discontinuities, as occurred with cause-of-death in 1999. The General Equivalence Maps (GEMs), while useful for suggesting potential maps do not provide guidance regarding the frequency of any matches. Longitudinal data comparisons can only be reliable if they use comparability ratios or factors which have been calculated using records coded in both classification systems. This study utilized 3,969 de-identified dually coded records to examine raw comparability ratios, as well as the comparability ratios between the Joint Commission Core Measures. The raw comparability factor results range from 16.216 for Nicotine dependence, unspecified, uncomplicated to 118.009 for Chronic obstructive pulmonary disease, unspecified. The Joint Commission Core Measure comparability factor results range from 27.15 for Acute Respiratory Failure to 130.16 for Acute Myocardial Infarction. These results indicate significant differences in comparability between ICD-9-CM and ICD-10-CM code assignment, including when the codes are used for external reporting such as the Joint Commission Core Measures. To prevent errors in decision-making and reporting, all stakeholders relying on longitudinal data for measure reporting and other purposes should investigate the impact of the conversion on their data.

  13. Evolution of crystalline target rocks and impactites in the chesapeake bay impact structure, ICDP-USGS eyreville B core

    USGS Publications Warehouse

    Horton, J.W.; Kunk, M.J.; Belkin, H.E.; Aleinikoff, J.N.; Jackson, J.C.; Chou, I.-Ming

    2009-01-01

    The 1766-m-deep Eyreville B core from the late Eocene Chesapeake Bay impact structure includes, in ascending order, a lower basement-derived section of schist and pegmatitic granite with impact breccia dikes, polymict impact breccias, and cataclas tic gneiss blocks overlain by suevites and clast-rich impact melt rocks, sand with an amphibolite block and lithic boulders, and a 275-m-thick granite slab overlain by crater-fill sediments and postimpact strata. Graphite-rich cataclasite marks a detachment fault atop the lower basement-derived section. Overlying impactites consist mainly of basement-derived clasts and impact melt particles, and coastalplain sediment clasts are underrepresented. Shocked quartz is common, and coesite and reidite are confirmed by Raman spectra. Silicate glasses have textures indicating immiscible melts at quench, and they are partly altered to smectite. Chrome spinel, baddeleyite, and corundum in silicate glass indicate high-temperature crystallization under silica undersaturation. Clast-rich impact melt rocks contain ??- cristobalite and monoclinic tridymite. The impactites record an upward transition from slumped ground surge to melt-rich fallback from the ejecta plume. Basement-derived rocks include amphibolite-facies schists, greenschist(?)-facies quartz-feldspar gneiss blocks and subgreenschist-facies shale and siltstone clasts in polymict impact breccias, the amphibolite block, and the granite slab. The granite slab, underlying sand, and amphibolite block represent rock avalanches from inward collapse of unshocked bedrock around the transient crater rim. Gneissic and massive granites in the slab yield U-Pb sensitive high-resolution ion microprobe (SHRIMP) zircon dates of 615 ?? 7 Ma and 254 ?? 3 Ma, respectively. Postimpact heating was 7lt;~350 ??C in the lower basementderived section based on undisturbed 40Ar/ 39Ar plateau ages of muscovite and <~150

  14. Geochemical studies of the SUBO 18 (Enkingen) drill core and other impact breccias from the Ries crater, Germany

    NASA Astrophysics Data System (ADS)

    Reimold, Wolf Uwe; McDonald, Iain; Schmitt, Ralf-Thomas; Hansen, Birgit; Jacob, Juliane; Koeberl, Christian

    2013-09-01

    Suevite and melt breccia compositions in the boreholes Enkingen and Polsingen are compared with compositions of suevites from other Ries boreholes and surface locations and discussed in terms of implications for impact breccia genesis. No significant differences in average chemical compositions for the various drill cores or surface samples are noted. Compositions of suevite and melt breccia from southern and northeastern sectors of the Ries crater do not significantly differ. This is in stark contrast to the published variations between within-crater and out-of-crater suevites from northern and southern sectors of the Bosumtwi impact structure, Ghana. Locally occurring alteration overprint on drill cores—especially strong on the carbonate-impregnated suevite specimens of the Enkingen borehole—does affect the average compositions. Overall, the composition of the analyzed impact breccias from Ries are characterized by very little macroscopically or microscopically recognized sediment-clast component; the clast populations of suevite and impact melt breccia are dominated consistently by granitic and intermediate granitoid components. The Polsingen breccia is significantly enriched in a dioritic clast component. Overall, chemical compositions are of intermediate composition as well, with dioritic-granodioritic silica contents, and relatively small contributions from mafic target components. Selected suevite samples from the Enkingen core have elevated Ni, Co, Cr, and Ir contents compared with previously analyzed suevites from the Ries crater, which suggest a small meteoritic component. Platinum-group element (PGE) concentrations for some of the enriched samples indicate somewhat elevated concentrations and near-chondritic ratios of the most immobile PGE, consistent with an extraterrestrial contribution of 0.1-0.2% chondrite-equivalent.

  15. Impacts of Light Precipitation Detection with Dual Frequency Radar on Global Precipitation Measurement Core Observatory (GPM/DPR)

    NASA Astrophysics Data System (ADS)

    Takayabu, Y. N.; Hamada, A.; Oki, R.; Kachi, M.; Kubota, T.; Iguchi, T.; Shige, S.; Nakamura, K.

    2014-12-01

    The Dual-frequency Precipitation Radar (DPR) on board the GPM Core Observatory consists of Ku-band (13.6 GHz) and Ka-band (35.5 GHz) radars, with an improved minimum detection sensitivity of precipitation compared to the Tropical Rainfall Measuring Mission Precipitation Radar (TRMM PR). We have studied impacts of improved detection sensitivity with the GPM DPR compared with the TRMM PR. One example of light precipitation is, a scattered rainfall around a trough over the subtropical South Pacific Ocean, which consists of weak but erect precipitation reaching over the melting level of ~2.5 km and trailing precipitation above, which reaches as high as 5km. Another example is a light anvil precipitation spreading from convective cores of a storm in the upper troposphere, overcasting shallow convective precipitation below. The ability of globally detecting such light precipitation will improve our knowledge of precipitation processes. Utilizing an early version of the DPR product, a quick evaluation on statistical impacts of increasing the detection sensitivity from 17dBZ to 12dBZ has been performed. Here, 17dBZ is the value which is mostly accepted as the performed detection sensitivity of the TRMM PR, and 12dBZ is the guaranteed sensitivity for GPM Ka-band radar. For the near surface precipitation, impacts are significant in terms of numbers, but limited to several regions in terms of the rainfall volume. Volume impacts are much larger at the upper troposphere, which is indicated by the detection of the anvil precipitation, for example. The upper level improvements are mostly found where the deep precipitation systems exist. Quantitative discussions utilizing the latest version of the DPR data, which is scheduled to be released to the public in September, will be presented at the session.

  16. The impact of drought and air pollution on metal profiles in peat cores.

    PubMed

    Souter, Laura; Watmough, Shaun A

    2016-01-15

    Peat cores have long been used to reconstruct atmospheric metal deposition; however, debate remains regarding how well historical depositional patterns are preserved in peat. This study examined peat cores sampled from 14 peatlands in the Sudbury region of Ontario, Canada, which has a well-documented history of acid and metal deposition. Copper (Cu) and lead (Pb) concentrations within individual peat cores were strongly correlated and were elevated in the upper 10 cm, especially in the sites closest to the main Copper Cliff smelter. In contrast, nickel (Ni) and cobalt (Co) concentrations were often elevated at depths greater than 10 cm, indicating much greater post-depositional movement of these metals compared with Cu and Pb. Post-depositional movement of metals is supported by the observation that Ni and Co concentrations in peat pore water increased by approximately 530 and 960% for Ni and Co, respectively between spring and summer due to drought-induced acidification, but there was much less change in Cu concentration. Sphagnum cover and (210)Pb activity measured at 10 cm at the 14 sites significantly increased with distance from Copper Cliff, and the surface peat von Post score decreased with distance from Copper Cliff, indicating the rate of peat formation increases with distance from Sudbury presumably as a result of improved Sphagnum survival. This study shows that the ability of peat to preserve deposition histories of some metals is strongly affected by drought-induced post-depositional movement and that loss of Sphagnum due to air pollution impairs the rate of peat formation, further affecting metal profiles in peatlands.

  17. Screw dislocations in complex, low symmetry oxides: core structures, energetics, and impact on crystal growth.

    PubMed

    Shahsavari, Rouzbeh; Chen, Lu

    2015-02-04

    Determining the atomic structure and the influence of defects on properties of low symmetry oxides have long been an engineering pursuit. Here, we focus on five thermodynamically reversible monoclinic and orthorhombic polymorphs of dicalcium silicates (Ca2SiO3)-a key cement constituent-as a model system and use atomistic simulations to unravel the interplay between the screw dislocation core energies, nonplanar core structures, and Peierls stresses along different crystallographic planes. Among different polymorphs, we found that the α polymorphs (α-C2S) has the largest Peierls stress, corresponding to the most brittle polymorph, which make it attractive for grinding processes. Interestingly, our analyses indicate that this polymorphs has the lowest dislocation core energy, making it ideal for reactivity and crystal growth. Generally, we identified the following order in terms of grinding efficiency based on screw dislocation analysis, α-C2S > αH-C2S > αL-C2S > β-C2S > γ-C2S, and the following order in term of reactivity, α -C2S > αL-C2S > γ-C2S > αH-C2S > β-C2S. This information, combined with other deformation-based mechanisms, such as twinning and edge dislocation, can provide crucial insights and guiding hypotheses for experimentalists to tune the cement grinding mechanisms and reactivity processes for an overall optimum solution with regard to both energy consumption and performance. Our findings significantly broaden the spectrum of strategies for leveraging both crystallographic directions and crystal symmetry to concurrently modulate mechanics and crystal growth processes within an identical chemical composition.

  18. Technology, science, and environtmental impact of a novel Cu-Ag core-shell solderless interconnect system

    NASA Astrophysics Data System (ADS)

    Kammer, Milea Joy

    Tin-based solder is ubiquitous in microelectronics manufacturing and plays a critical role in electronic packaging and attachment. While manufacturers of consumer electronics have made the transition to the use of lead-free solder, there are still a variety of reliability issues associated with these lead-free alternatives, particularly for high performance, high reliability applications. Because of these performance short-comings, researchers are still searching for a material, an alloy, or a unique alternative that can meet the thermal, mechanical, and electrical requirements for conventional reflow solder applications. In an effort to produce a more reliable alternative, Kim et al. proposed the low-temperature (200°C) sintering of copper-silver core-shell particles as a viable solderless interconnect technology. This technology is based on the silver atoms from the shell diffusing by surface diffusion to form sintered necks between copper particles, and therefore dewetting most of the copper surfaces. This study presents a 3-fold, in-depth evaluation of this Cu-Ag core-shell lead-free solderless interconnect technology focusing on solder paste development and prototyping, silver thin film stress relaxation and dewetting kinetics, and the environmental impacts associated with this new technology. First, an evaluation of the starting particle consistency and sintered compact mechanical properties determined that a specific core-shell particle geometry (1microm average core diameter and 10nm shell thickness) outperformed other combinations, exhibiting the highest modulus and yield strengths in sintered compacts, of 620 MPa and 40-60 MPa respectively. In particular, yield strengths for sintered compacts are similar to those reported for Sn-3.5Ag-0.75Cu (a commonly used lead-free solder) for the same strain rate. Following particle evaluations, the development of a functioning flux formulation was a key factor in the creation of a viable drop-in replacement. The

  19. Petrography of the Suevite-like Depth Interval (1397-1550 m) in Drill Core Eyreville-B, Chesapeake Bay Impact Structure, USA

    NASA Astrophysics Data System (ADS)

    Wittmann, A.; Reimold, W. U.; Hansen, B.; Kenkmann, T.

    2008-03-01

    A sub-division of suevite-like deposits in a drill core through the Chesapeake Bay impact structure based on component-size distribution and petrography suggests a gradation from groundsurge to fallback within the first ~6 minutes after impact.

  20. Drill core LB-08A, Bosumtwi impact structure, Ghana: Geochemistry of fallback breccia and basement samples from the central uplift

    NASA Astrophysics Data System (ADS)

    Ferrière, Ludovic; Koeberl, Christian; Reimold, Wolf Uwe; Mader, Dieter

    The 1.07 Myr old Bosumtwi impact structure in Ghana (West Africa), which measures 10.5 km in diameter and is largely filled by Lake Bosumtwi, is associated with one of four currently known tektite strewn fields. Two boreholes were drilled to acquire hard-rock samples of the deep crater moat and from the flank of the central uplift (LB-07A and LB-08A, respectively) during a recent ICDP-sponsored drilling project. Here we present results of major and trace element analysis of 112 samples from drill core LB-08A. This core, which was recovered between 235.6 and 451.33 m depth below lake level, contains polymict lithic breccia intercalated with suevite, which overlies fractured/brecciated metasediment. The basement is dominated by meta-graywacke (from fine-grained to gritty), but also includes some phyllite and slate, as well as suevite dikelets and a few units of a distinct light greenish gray, medium-grained meta-graywacke. Most of the variations of the major and trace element abundances in the different lithologies result from the initial compositional variations of the various target rock types, as well as from aqueous alteration processes, which have undeniably affected the different rocks. Suevite from core LB-08A (fallback suevite) and fallout suevite samples (from outside the northern crater rim) display some differences in major (mainly in MgO, CaO, and Na2O contents) and minor (mainly Cr and Ni) element abundances that could be related to the higher degree of alteration of fallback suevites, but also result from differences in the clast populations of the two suevite populations. For example, granite clasts are present in fallout suevite but not in fallback breccia, and calcite clasts are present in fallback breccia and not in fallout suevite. Chondrite-normalized rare earth element abundance patterns for polymict impact breccia and basement samples are very similar to each other. Siderophile element contents in the impact breccias are not significantly

  1. Multigeneration impacts on Daphnia magna of carbon nanomaterials with differing core structures and functionalizations.

    PubMed

    Arndt, Devrah A; Chen, Jian; Moua, Maika; Klaper, Rebecca D

    2014-03-01

    Several classes of contaminants have been shown to have multigenerational impacts once a parental generation has been exposed. Acute and chronic toxicity are described for several types of nanomaterials in the literature; however, no information is available on the impact of nanomaterials on future generations of organisms after the exposure is removed. In the present study, the authors examined the impacts of carbon nanomaterials (CNMs), including fullerenes (C60), single-walled carbon nanotubes (SWCNTs), and multiwalled carbon nanotubes (MWCNTs) with neutral, positive, and negative functional groups to F1 and F2 generation daphnids after an F0 exposure. Data from the present study indicate that multigenerational toxicity is present with certain nanomaterial exposures and is highly dependent on the surface chemistry of the nanomaterial. Many CNMs that showed toxicity to exposed F0 daphnids in previous experiments did not induce multigenerational toxicity. Certain nanomaterials, however, such as C60-malonate, SWCNTs, SWCNT-CONH2 , and MWCNTs, caused a significant decrease in either survival or reproduction in F1 daphnids; and SWCNT-CONH2 decreased reproduction out to the F2 generation. Impacts of nanomaterials on F1 and F2 size were small and lacked clear patterns, indicating that CNMs have minimal multigenerational impacts on size. Industries should take into account how surface chemistry influences nanomaterial toxicity to future generations of organisms to create sustainable nanomaterials that do not harm freshwater ecosystems.

  2. Ecotoxicological impact assessment of heavy metals in core sediments of a tropical estuary.

    PubMed

    Harikumar, P S; Nasir, U P

    2010-10-01

    Down core variation of heavy metals in three sediment cores from Cochin estuary was studied. The average concentration of iron, manganese, nickel, copper, zinc, cadmium, lead and mercury in each slices of sediment was determined. Quality of the sediments were evaluated based on sediment quality guidelines, pollution load index, and sum of toxic units and with effect range low/effect range median and threshold effect level/probable effect level values of environmental protection agency guidelines. The degree of contamination for each station was determined. The results of the study revealed higher concentration of heavy metals in surface layers than in deeper ones. The concentration of heavy metals in some stations exceeded the effect range median levels, which represents a probable effect range with in which adverse biological effects frequently occur. The spatial variation of heavy metals showed more contamination in the downstream at Pathalam industrial site. Statistical analysis showed that the correlation among different parameters differs with respect to stations. The present study highlighted severe heavy metal contamination of Cochin estuary with increased rate of deposition.

  3. Potential Transference of Escherichia coli O157:H7 from Contaminated Coring Knife to Field-cored Lettuce and Impact of Holding Time and Temperature on Its Growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field coring is a recent development in iceberg lettuce harvesting, where the outer leaves and the cores of the lettuce heads are removed at the time of harvesting in order to reduce shipping waste and maximize production yield during processing for fresh-cut products. However, research on the effe...

  4. Anthropogenic impact on the Swartvlei lake system in the Wilderness area (South Africa) as reflected in a sediment core

    NASA Astrophysics Data System (ADS)

    Haberzettl, Torsten; Kirsten, Kelly; Franz, Sarah; Reinwarth, Bastian; Baade, Jussi; Daut, Gerhard; Kasper, Thomas; Meadows, Michael; Su, Youliang; Mäusbacher, Roland

    2016-04-01

    Swartvlei is one of the most thoroughly investigated lacustrine coastal systems in South Africa. However, studies focussing on anthropogenic impacts on sediment deposition in the most recent past (i.e., the last 30-40 years) are rare. A 96 cm long sediment core, covering the past two centuries, provides evidence for intense changes over the last few decades probably related to anthropogenic activities, such as farming, water abstraction etc. A decrease in marine influence is observed starting somewhat earlier but was potentially supported by human management activities. The development of the age-depth model turned out to be a serious issue, as old marine carbon affected samples impacted the robustness of the chronology, hence further investigations are required in most coastal geoarchives from South Africa. A multi-dating approach using several methods is suggested as errors in the chronology distinctly impact paleoenvironmental reconstructions (timing, flux rates etc.). In this context initial paleomagnetic secular variation data are presented, which needs further exploration and inclusion in the future.

  5. Core layering

    NASA Astrophysics Data System (ADS)

    Jacobson, S. A.; Rubie, D. C.; Hernlund, J. W.; Morbidelli, A.

    2015-12-01

    We have created a planetary accretion and differentiation model that self-consistently builds and evolves Earth's core. From this model, we show that the core grows stably stratified as the result of rising metal-silicate equilibration temperatures and pressures, which increases the concentrations of light element impurities into each newer core addition. This stable stratification would naturally resist convection and frustrate the onset of a geodynamo, however, late giant impacts could mechanically mix the distinct accreted core layers creating large homogenous regions. Within these regions, a geodynamo may operate. From this model, we interpret the difference between the planetary magnetic fields of Earth and Venus as a difference in giant impact histories. Our planetary accretion model is a numerical N-body integration of the Grand Tack scenario [1]—the most successful terrestrial planet formation model to date [2,3]. Then, we take the accretion histories of Earth-like and Venus-like planets from this model and post-process the growth of each terrestrial planet according to a well-tested planetary differentiation model [4,5]. This model fits Earth's mantle by modifying the oxygen content of the pre-cursor planetesimals and embryos as well as the conditions of metal-silicate equilibration. Other non-volatile major, minor and trace elements included in the model are assumed to be in CI chondrite proportions. The results from this model across many simulated terrestrial planet growth histories are robust. If the kinetic energy delivered by larger impacts is neglected, the core of each planet grows with a strong stable stratification that would significantly impede convection. However, if giant impact mixing is very efficient or if the impact history delivers large impacts late, than the stable stratification can be removed. [1] Walsh et al. Nature 475 (2011) [2] O'Brien et al. Icarus 223 (2014) [3] Jacobson & Morbidelli PTRSA 372 (2014) [4] Rubie et al. EPSL 301

  6. Modification of magicity toward the dripline and its impact on electron-capture rates for stellar core collapse

    NASA Astrophysics Data System (ADS)

    Raduta, Ad. R.; Gulminelli, F.; Oertel, M.

    2016-02-01

    The importance of microphysical inputs from laboratory nuclear experiments and theoretical nuclear structure calculations in the understanding of core-collapse dynamics and the subsequent supernova explosion is largely recognized in the recent literature. In this work, we analyze the impact of the masses of very neutron-rich nuclei on the matter composition during collapse and the corresponding electron-capture rate. To this end, we introduce an empirical modification of the popular Duflo-Zuker mass model to account for possible shell quenching far from stability. We study the effect of this quenching on the average electron-capture rate. We show that the pre-eminence of the closed shells with N =50 and N =82 in the collapse dynamics is considerably decreased if the shell gaps are reduced in the region of 78Ni and beyond. As a consequence, local modifications of the overall electron-capture rate of up to 30% can be expected, depending on the strength of magicity quenching. This finding has potentially important consequences on the entropy generation, the neutrino emissivity, and the mass of the core at bounce. Our work underlines the importance of new experimental measurements in this region of the nuclear chart, the most crucial information being the nuclear mass and the Gamow-Teller strength. Reliable microscopic calculations of the associated elementary rate, in a wide range of temperatures and electron densities, optimized on these new empirical information, will be additionally needed to get quantitative predictions of the collapse dynamics.

  7. Effects of the Core-collapse Supernova Ejecta Impact on a Rapidly Rotating Massive Companion Star

    NASA Astrophysics Data System (ADS)

    Zhu, Chunhua; Lü, Guoliang; Wang, Zhaojun

    2017-02-01

    We investigate the effects of the core-collapse supernova (CCSN) ejecta on a rapidly rotating and massive companion star. We show that the stripped mass is twice as high as that of a massive but nonrotating companion star. In close binaries with orbital periods of about 1 day, the stripped masses reach up to ∼ 1 {M}ȯ . By simulating the evolutions of the rotational velocities of the massive companion stars based on different stripped masses, we find that the rotational velocity decreases greatly for a stripped mass higher than about 1 {M}ȯ . Of all the known high-mass X-ray binaries (HMXBs), Cygnus X-3 and 1WGA J0648.024418 have the shortest orbital periods, 0.2 and 1.55 days, respectively. The optical counterpart of the former is a Wolf-Rayet star, whereas it is a hot subdwarf for the latter. Applying our model to the two HMXBs, we suggest that the hydrogen-rich envelopes of their optical counterparts may have been stripped by CCSN ejecta.

  8. Impact of HCV core gene quasispecies on hepatocellular carcinoma risk among HALT-C trial patients.

    PubMed

    El-Shamy, Ahmed; Pendleton, Matthew; Eng, Francis J; Doyle, Erin H; Bashir, Ali; Branch, Andrea D

    2016-06-01

    Mutations at positions 70 and/or 91 in the core protein of genotype-1b, hepatitis C virus (HCV) are associated with hepatocellular carcinoma (HCC) risk in Asian patients. To evaluate this in a US population, the relationship between the percentage of 70 and/or 91 mutant HCV quasispecies in baseline serum samples of chronic HCV patients from the HALT-C trial and the incidence of HCC was determined by deep sequencing. Quasispecies percentage cut-points, ≥42% of non-arginine at 70 (non-R(70)) or ≥98.5% of non-leucine at 91 (non-L(91)) had optimal sensitivity at discerning higher or lower HCC risk. In baseline samples, 88.5% of chronic HCV patients who later developed HCC and 68.8% of matched HCC-free control patients had ≥42% non-R(70) quasispecies (P = 0.06). Furthermore, 30.8% of patients who developed HCC and 54.7% of matched HCC-free patients had quasispecies with ≥98.5% non-L(91) (P = 0.06). By Kaplan-Meier analysis, HCC incidence was higher, but not statistically significant, among patients with quasispecies ≥42% non-R(70) (P = 0.08), while HCC incidence was significantly reduced among patients with quasispecies ≥98.5% non-L(91) (P = 0.01). In a Cox regression model, non-R(70) ≥42% was associated with increased HCC risk. This study of US patients indicates the potential utility of HCV quasispecies analysis as a non-invasive biomarker of HCC risk.

  9. Giant viruses at the core of microscopic wars with global impacts.

    PubMed

    Villain, Adrien; Gallot-Lavallée, Lucie; Blanc, Guillaume; Maumus, Florian

    2016-04-01

    The unicellular eukaryotes (also called protists) that inhabit the contemporary oceans have large impacts on major biogeochemical cycles. Populations of oceanic protists are to a large extent regulated by their viral parasites, especially nucleocytoplasmic large DNA viruses (NCLDVs). NCLDVs can themselves be the prey of smaller viruses called virophages and can also be infected by transposable elements termed transpovirons. These entangled parasitisms have fostered the emergence of sophisticated infection and defence strategies. In addition persistent contact has facilitated the exchange of genes between different parties. Recent advances shed light on the strategies that govern such microbial wars. Endogenous virophage-like elements found in the genome of a marine alga could for instance provide the host acquired immunity against NCLDVs. In return, it was recently speculated that virophage sequences can be hijacked by NCLDVs and used as genetic weapons against virophages.

  10. Impacts of the SCA Core Framework on High Speed Broadband Waveform in SDR Handheld System

    NASA Astrophysics Data System (ADS)

    Oh, Sangchul; Park, Namhoon; Kwon, Ohjun; Kim, Yeongjin

    In this paper, we have shown a major element occupying the large portion of software communications architecture (SCA)-based software defined radio (SDR) handheld embedded system and an important feature for implementing a high speed broadband radio to an SCA waveform through a couple of experiments. First, this paper identifies the main items possessing the large portion of SCA-based SDR handheld embedded system by the experiment on the target platform which is similar to a commercial mobile handheld system. Both the world interoperabillity for microwave access (WiMAX) and high speed downlink packet access (HSDPA) waveform software packages are used as an SCA waveform application. This paper also presents the results of the relative binary size distribution of SCA software resources for looking for the major elements making an SCA-based SDR handheld embedded system heavier. As a result, when focusing on the relative weight portion of SCA core framework (CF), the SCA CF takes 16% up and others have 84% out of the whole binary size distribution of SCA software resources. The results of the experiment give us notice that the weight portion of SCA CF is minor and compatible with the overall software binary size needs of an SCA-based SDR handheld embedded system, on the other hand, the practical problem on the lightweight is in a common object request broker architecture (CORBA) and extensible markup language (XML) parser resources. Second, this paper describes an important feature for implementing a high speed broadband radio to an SCA waveform and presents the performance evaluation results of the SCA port communication on both power PC (PPC) 405 and x86 processor platforms. The PPC 405 platform, which is similar to a commercial mobile handset, takes the value of average round trip time (RTT) with a maximum of thirty six millisecond. The x86 platform, however, which is analogous to a server platform, maintains stable micro-second resolution. From our experiments, we

  11. A Model of the Chicxulub Impact Basin Based on Evaluation of Geophysical Data, Well Logs, and Drill Core Samples

    NASA Technical Reports Server (NTRS)

    Sharpton, Virgil L.; Marin, Luis E.; Carney, John D.; Lee, Scott; Ryder, Graham; Schuraytz, Benjamin C.; Sikora, Paul; Spudis, Paul D.

    1996-01-01

    Abundant evidence now shows that the buried Chicxulub structure in northern Yucatan, Mexico, is indeed the intensely sought-after source of the ejecta found world-wide at the Cretaceous-Tertiary (K/T) boundary. In addition to large-scale concentric patterns in gravity and magnetic data over the structure, recent analyses of drill-core samples reveal a lithological assemblage similar to that observed at other terrestrial craters. This assemblage comprises suevite breccias, ejecta deposit breccias (Bunte Breccia equivalents), fine-grained impact melt rocks, and melt-matrix breccias. All these impact-produced lithologies contain diagnostic evidence of shock metamorphism, including planar deformation features in quartz, feldspar, and zircons; diaplectic glasses of quartz and feldspar; and fused mineral melts and whole-rock melts. In addition, elevated concentrations of Ir, Re, and Os, in meteoritic relative proportions, have been detected in some melt-rock samples from the center of the structure. Isotopic analyses, magnetization of melt-rock samples, and local stratigraphic constraints identify this crater as the source of K/T boundary deposits.

  12. Petrography, mineralogy, and geochemistry of deep gravelly sands in the Eyreville B core, Chesapeake Bay impact structure

    USGS Publications Warehouse

    Bartosova, Katerina; Gier, Susanne; Horton, J. Wright; Koeberl, Christian; Mader, Dieter; Dypvik, Henning

    2010-01-01

    The ICDP–USGS Eyreville drill cores in the Chesapeake Bay impact structure reached a total depth of 1766 m and comprise (from the bottom upwards) basement-derived schists and granites/pegmatites, impact breccias, mostly poorly lithified gravelly sand and crystalline blocks, a granitic slab, sedimentary breccias, and postimpact sediments. The gravelly sand and crystalline block section forms an approximately 26 m thick interval that includes an amphibolite block and boulders of cataclastic gneiss and suevite. Three gravelly sands (basal, middle, and upper) are distinguished within this interval. The gravelly sands are poorly sorted, clast supported, and generally massive, but crude size-sorting and subtle, discontinuous layers occur locally. Quartz and K-feldspar are the main sand-size minerals and smectite and kaolinite are the principal clay minerals. Other mineral grains occur only in accessory amounts and lithic clasts are sparse (only a few vol%). The gravelly sands are silica rich (~80 wt% SiO2). Trends with depth include a slight decrease in SiO2 and slight increase in Fe2O3. The basal gravelly sand (below the cataclasite boulder) has a lower SiO2 content, less K-feldspar, and more mica than the higher sands, and it contains more lithic clasts and melt particles that are probably reworked from the underlying suevite. The middle gravelly sand (below the amphibolite block) is finer-grained, contains more abundant clay minerals, and displays more variable chemical compositions than upper gravelly sand (above the block). Our mineralogical and geochemical results suggest that the gravelly sands are avalanche deposits derived probably from the nonmarine Potomac Formation in the lower part of the target sediment layer, in contrast to polymict diamictons higher in the core that have been interpreted as ocean-resurge debris flows, which is in agreement with previous interpretations. The mineralogy and geochemistry of the gravelly sands are typical for a passive

  13. Preliminary Assessment of the Impact on Reactor Vessel dpa Rates Due to Installation of a Proposed Low Enriched Uranium (LEU) Core in the High Flux Isotope Reactor (HFIR)

    SciTech Connect

    Daily, Charles R.

    2015-10-01

    An assessment of the impact on the High Flux Isotope Reactor (HFIR) reactor vessel (RV) displacements-per-atom (dpa) rates due to operations with the proposed low enriched uranium (LEU) core described by Ilas and Primm has been performed and is presented herein. The analyses documented herein support the conclusion that conversion of HFIR to low-enriched uranium (LEU) core operations using the LEU core design of Ilas and Primm will have no negative impact on HFIR RV dpa rates. Since its inception, HFIR has been operated with highly enriched uranium (HEU) cores. As part of an effort sponsored by the National Nuclear Security Administration (NNSA), conversion to LEU cores is being considered for future HFIR operations. The HFIR LEU configurations analyzed are consistent with the LEU core models used by Ilas and Primm and the HEU balance-of-plant models used by Risner and Blakeman in the latest analyses performed to support the HFIR materials surveillance program. The Risner and Blakeman analyses, as well as the studies documented herein, are the first to apply the hybrid transport methods available in the Automated Variance reduction Generator (ADVANTG) code to HFIR RV dpa rate calculations. These calculations have been performed on the Oak Ridge National Laboratory (ORNL) Institutional Cluster (OIC) with version 1.60 of the Monte Carlo N-Particle 5 (MCNP5) computer code.

  14. Alvermann & Jackson: Response to "Beyond the Common Core: Examining 20 Years of Literacy Priorities and Their Impact on Struggling Readers"

    ERIC Educational Resources Information Center

    Alvermann, Donna E.; Jackson, Glen

    2016-01-01

    When the editors of "Literacy Research and Instruction" invited Donna Alvermann and Glenn Jackson to respond to "Beyond the Common Core: Examining 20 Years of Literacy Priorities and Their Impact on Struggling Readers," they both instantly recognized the strengths and limitations in their collaboration. In the strengths corner,…

  15. Pollen core assemblages as indicator of Polynesian and European impact on the vegetation cover of Auckland Isthmus catchment, New Zealand

    NASA Astrophysics Data System (ADS)

    Abrahim, Ghada M. S.; Parker, Robin J.; Horrocks, Mark

    2013-10-01

    Tamaki Estuary is an arm of the Hauraki Gulf situated on the eastern side of central Auckland. Over the last 100 years, Tamaki catchment has evolved from a nearly rural landscape to an urbanised and industrialised area. Pollen, 14C and glass shards analyses, were carried out on three cores collected along the estuary with the aim to reconstruct the estuary's history over the last ˜8000 years and trace natural and anthropogenic effects recorded in the sediments. Glass shard analysis was used to establish key tephra time markers such as the peralkaline eruption of Mayor Island, ˜6000 years BP. During the pre-Polynesian period (since at least 8000 years BP), regional vegetation was podocarp/hardwood forest dominated by Dacrydium cupressinun, Prumnopits taxifolia, and Metrosideros. Major Polynesian settler impact (commencing ˜700 yr BP) was associated with forest clearance as indicated by a sharp decline in forest pollen types. This coincided with an increase in bracken (Pteridium esculentum) spores and grass pollen. Continuing landscape disturbance during European settlement (commencing after 1840 AD) was accompanied by the distinctive appearance of exotic pollen taxa such as Pinus.

  16. Impact of the Cooling Equipment on the Key Design Parameters of a Core-Form Power Transformer

    NASA Astrophysics Data System (ADS)

    Orosz, Tamás; Tamus, Zoltán Ádám

    2016-12-01

    The first step in the transformer design process is to find the active part's key design parameters. This is a non-linear mathematical optimisation task, which becomes more complex if the economic conditions are considered by the capitalisation of the losses. Geometric programming combined with the method of branch and bound can be an effective and accurate tool for this task even in the case of core-form power transformers, when formulating the short-circuit impedance in the required form is problematic. Most of the preliminary design methods consider only the active part of the transformer and the capitalised costs in order to determine the optimal key design parameters. In this paper, an extension of this meta-heuristic transformer optimisation model, which takes the cost of the insulating oil and the cooling equipment into consideration, is presented. Moreover, the impact of the new variables on the optimal key design parameters of a transformer design is examined and compared with the previous algorithm in two different economic scenarios. Significant difference can be found between the optimal set of key-design parameters if these new factors are considered.

  17. Impacts of core-shell structures on properties of lanthanide-based nanocrystals: crystal phase, lattice strain, downconversion, upconversion and energy transfer.

    PubMed

    Kar, Arik; Patra, Amitava

    2012-06-21

    This feature article highlights the new development and current status of rare-earth (RE) based core-shell nanocrystals, which is one of the new classes of hybrid nanostructures. Attractive properties of rare-earth based nanomaterials include extremely narrow emission bands, long lifetimes, large Stoke's shifts, photostability and absence of blinking that can be exploited for biophotonic and photonic applications. Core-shell nanostructures have been attracting a great deal of interest to improve the luminescence efficiency by the elimination of deleterious cross-relaxation. The main focus of this feature article is to address the impacts of core-shell structures on the properties of lanthanide based nanocrystals including crystal phase, lattice strain, downconversion emission, upconversion emission and energy transfer. We describe general synthetic methodologies to design core-shell nanostructure materials. An interesting finding reported is that the local environment of an ion in the core-shell structure significantly affects the modifications of radiative and nonradiative relaxation mechanisms. Finally, a tentative outlook on future developments of this research field is given. Here, we attempt to identify the critical parameters governing the design of luminescent lanthanide based core-shell nanostructures.

  18. Wrinkle-assisted linear assembly of hard-core/soft-shell particles: impact of the soft shell on the local structure.

    PubMed

    Müller, Mareen; Karg, Matthias; Fortini, Andrea; Hellweg, Thomas; Fery, Andreas

    2012-04-07

    This article addresses wrinkle assisted assembly of core-shell particles with hard cores and soft poly-(N-isopropylacrylamide) shells. As core materials we chose silica as well as silver nanoparticles. The assembled structures show that the soft shells act as a separator between the inorganic cores. Anisotropic alignment is found on two length scales, macroscopically guided through the wrinkle structure and locally due to deformation of the polymer shell leading to smaller inter-core separations as compared to assembly on flat substrates without confinement. The structures were analysed by means of scanning electron microscopy. Radial distribution functions are shown, clearly highlighting the impact of confinement on nearest neighbour distances and symmetry. The observed ordering is directly compared to Monte-Carlo simulations for hard-core/soft-shell particles, showing that the observed symmetries are a consequence of the soft interaction potential and differ qualitatively from a hard-sphere situation. For the silver-poly-(N-isopropylacrylamide) particles, we show UV-vis absorbance measurements revealing optical anisotropy of the generated structures due to plasmon coupling. Furthermore, the high degree of order of the assembled structures on macroscopic areas is demonstrated by laser diffraction effects.

  19. Variability in the Precore and Core Promoter Regions of HBV Strains in Morocco: Characterization and Impact on Liver Disease Progression

    PubMed Central

    Kitab, Bouchra; Essaid El Feydi, Abdellah; Afifi, Rajaa; Trepo, Christian; Benazzouz, Mustapha; Essamri, Wafaa; Zoulim, Fabien; Chemin, Isabelle; Alj, Hanane Salih; Ezzikouri, Sayeh; Benjelloun, Soumaya

    2012-01-01

    Background Hepatitis B virus (HBV) is one of the most common human pathogens that cause aggressive hepatitis and advanced liver disease (AdLD), including liver cirrhosis and Hepatocellular Carcinoma. The persistence of active HBV replication and liver damage after the loss of hepatitis B e antigen (HBeAg) has been frequently associated with mutations in the pre-core (pre-C) and core promoter (CP) regions of HBV genome that abolish or reduce HBeAg expression. The purpose of this study was to assess the prevalence of pre-C and CP mutations and their impact on the subsequent course of liver disease in Morocco. Methods/Principal Findings A cohort of 186 patients with HBeAg-negative chronic HBV infection was studied (81 inactive carriers, 69 with active chronic hepatitis, 36 with AdLD). Pre-C and CP mutations were analyzed by PCR-direct sequencing method. The pre-C stop codon G1896A mutation was the most frequent (83.9%) and was associated with a lower risk of AdLD development (OR, 0.4; 95% CI, 0.15–1.04; p = 0.04). HBV-DNA levels in patients with G1896A were not significantly different from the other patients carrying wild-type strains (p = 0.84). CP mutations C1653T, T1753V, A1762T/G1764A, and C1766T/T1768A were associated with higher HBV-DNA level and increased liver disease severity. Multiple logistic regression analysis showed that older age (≥40 years), male sex, high viral load (>4.3 log10 IU/mL) and CP mutations C1653T, T1753V, A1762T/G1764A, and C1766T/T1768A were independent risk factors for AdLD development. Combination of these mutations was significantly associated with AdLD (OR, 7.52; 95% CI, 4.8–8; p<0.0001). Conclusions This study shows for the first time the association of HBV viral load and CP mutations with the severity of liver disease in Moroccan HBV chronic carriers. The examination of CP mutations alone or in combination could be helpful for prediction of the clinical outcome. PMID:22905181

  20. Pre-impact tectonothermal evolution of the crystalline basement-derived rocks in the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure

    USGS Publications Warehouse

    Gibson, R.L.; Townsend, G.N.; Horton, J.W.; Reimold, W.U.

    2009-01-01

    Pre-impact crystalline rocks of the lowermost 215 m of the Eyreville B drill core from the Chesapeake Bay impact structure consist of a sequence of pelitic mica schists with subsidiary metagraywackes or felsic metavolcanic rocks, amphibolite, and calc-silicate rock that is intruded by muscovite (??biotite, garnet) granite and granite pegmatite. The schists are commonly graphitic and pyritic and locally contain plagioclase porphyroblasts, fi brolitic sillimanite, and garnet that indicate middle- to upper-amphibolite-facies peak metamorphic conditions estimated at ??0.4-0.5 GPa and 600-670 ??C. The schists display an intense, shallowly dipping, S1 composite shear foliation with local micrometer- to decimeter-scale recumbent folds and S-C' shear band structures that formed at high temperatures. Zones of chaotically oriented foliation, resembling breccias but showing no signs of retrogression, are developed locally and are interpreted as shear-disrupted fold hinges. Mineral textural relations in the mica schists indicate that the metamorphic peak was attained during D1. Fabric analysis indicates, however, that subhorizontal shear deformation continued during retrograde cooling, forming mylonite zones in which high-temperature shear fabrics (S-C and S-C') are overprinted by progressively lower- temperature fabrics. Cataclasites and carbonate-cemented breccias in more competent lithologies such as the calc-silicate unit and in the felsic gneiss found as boulders in the overlying impactite succession may refl ect a fi nal pulse of low-temperature cataclastic deformation during D1. These breccias and the shear and mylonitic foliations are cut by smaller, steeply inclined anastomosing fractures with chlorite and calcite infill (interpreted as D2). This D2 event was accompanied by extensive chlorite-sericitecalcite ?? epidote retrogression and appears to predate the impact event. Granite and granite pegmatite veins display local discordance to the S1 foliation, but elsewhere

  1. Geologic columns for the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure: Impactites and crystalline rocks, 1766 to 1096 m depth

    USGS Publications Warehouse

    Horton, J. Wright; Gibson, R.L.; Reimold, W.U.; Wittmann, A.; Gohn, G.S.; Edwards, L.E.

    2009-01-01

    The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville drill cores from the Chesapeake Bay impact structure provide one of the most complete geologic sections ever obtained from an impact structure. This paper presents a series of geologic columns and descriptive lithologic information for the lower impactite and crystalline-rock sections in the cores. The lowermost cored section (1766-1551 m depth) is a complex assemblage of mica schists that commonly contain graphite and fibrolitic sillimanite, intrusive granite pegmatites that grade into coarse granite, and local zones of mylonitic deformation. This basement-derived section is variably overprinted by brittle cataclastic fabrics and locally cut by dikes of polymict impact breccia, including several suevite dikes. An overlying succession of suevites and lithic impact breccias (1551-1397 m) includes a lower section dominated by polymict lithic impact breccia with blocks (up to 17 m) and boulders of cataclastic gneiss and an upper section (above 1474 m) of suevites and clast-rich impact melt rocks. The uppermost suevite is overlain by 26 m (1397-1371 m) of gravelly quartz sand that contains an amphibolite block and boulders of cataclasite and suevite. Above the sand, a 275-m-thick allochthonous granite slab (1371-1096 m) includes gneissic biotite granite, fine- and medium-to-coarse-grained biotite granites, and red altered granite near the base. The granite slab is overlain by more gravelly sand, and both are attributed to debris-avalanche and/or rockslide deposition that slightly preceded or accompanied seawater-resurge into the collapsing transient crater. ?? 2009 The Geological Society of America.

  2. Comparison of 20 nm silver nanoparticles synthesized with and without a gold core. Structure, dissolution in cell culture media, and biological impact on macrophages

    DOE PAGES

    Munusamy, Prabhakaran; Wang, Chongmin; Engelhard, Mark H.; ...

    2015-07-15

    Widespread use of silver nanoparticles raises questions of environmental impact and toxicity. Both silver particles and silver ions formed by particle dissolution may impact biological systems. Therefore it is important to understand the characteristics of silver nanoparticles and their stability in relevant media. The synthesis route can impact physical and chemical characteristics of the particles and we report the characterization and solution stability of three types of silver nanoparticles (20 nm particles with and without gold cores and 110 nm particles with gold cores) in cell culture media with serum proteins: FBS10%/RPMI. These nanoparticles were synthesized in aqueous solution andmore » characterized using both in situ and ex situ analysis methods. Dissolution studies were carried at particle concentrations from 1 µg/ml to 50 µg/ml. Particles with gold cores had smaller crystallite size and higher apparent solubility than pure silver particles. A dissolution model was found to describe the time variation of particle size and amount of dissolved silver for particle loadings above 9 µg/ml. An effective solubility product obtained from fitting the data was higher for the 20 nm gold core particles in comparison to the pure silver or 110 nm particles. Dissolution of the nanoparticles was enhanced by presence of serum proteins contained in fetal bovine serum. In addition, the protocol of the dispersion in the medium was found to influence particle agglomeration and dissolution. Results show that particle structure can impact the concentration of dissolved silver and the dose to which cells would be exposed during in vitro studies.« less

  3. Comparison of 20 nm silver nanoparticles synthesized with and without a gold core. Structure, dissolution in cell culture media, and biological impact on macrophages

    SciTech Connect

    Munusamy, Prabhakaran; Wang, Chongmin; Engelhard, Mark H.; Baer, Donald R.; Smith, Jordan N.; Liu, Chongxuan; Kodali, Vamsi K.; Thrall, Brian D.; Chen, Shu; Porter, Alexandra E.; Ryan, Mary P.

    2015-07-15

    Widespread use of silver nanoparticles raises questions of environmental impact and toxicity. Both silver particles and silver ions formed by particle dissolution may impact biological systems. Therefore it is important to understand the characteristics of silver nanoparticles and their stability in relevant media. The synthesis route can impact physical and chemical characteristics of the particles and we report the characterization and solution stability of three types of silver nanoparticles (20 nm particles with and without gold cores and 110 nm particles with gold cores) in cell culture media with serum proteins: FBS10%/RPMI. These nanoparticles were synthesized in aqueous solution and characterized using both in situ and ex situ analysis methods. Dissolution studies were carried at particle concentrations from 1 µg/ml to 50 µg/ml. Particles with gold cores had smaller crystallite size and higher apparent solubility than pure silver particles. A dissolution model was found to describe the time variation of particle size and amount of dissolved silver for particle loadings above 9 µg/ml. An effective solubility product obtained from fitting the data was higher for the 20 nm gold core particles in comparison to the pure silver or 110 nm particles. Dissolution of the nanoparticles was enhanced by presence of serum proteins contained in fetal bovine serum. In addition, the protocol of the dispersion in the medium was found to influence particle agglomeration and dissolution. Results show that particle structure can impact the concentration of dissolved silver and the dose to which cells would be exposed during in vitro studies.

  4. Impact of Surficial Weathering on the Magnetic Properties of Paleosols: a Core to Outcrop Comparison from the Bighorn Basin, WY

    NASA Astrophysics Data System (ADS)

    Maxbauer, D.; Fox, D. L.; Feinberg, J. M.; Clyde, W.

    2014-12-01

    Environmental magnetic studies of soils have generally focused on providing insights into the climate and environmental conditions that produce modern soils and geologically young paleosols (<5 Ma), but environmental magnetic analysis of more ancient paleosols has been limited. The Bighorn Basin Coring Project (BBCP) recently recovered ~300 m of sediment core spanning the Paleocene-Eocene boundary from the Polecat Bench locality in the Bighorn Basin, WY. Core scan images show that oxidative weathering extends some 20-30 m below the surface, suggesting that recent surficial weathering could have significantly altered the magnetic signals preserved in paleosols that crop out in this region. This study presents the first detailed core to outcrop comparison of paleosol magnetism of which we are aware. Nine paleosols from Polecat Bench, spanning the Paleocene-Eocene Thermal Maximum (PETM), have been sampled at high-resolution from outcrop trenches and core sediments. Importantly, these paleosols are stratigraphically below the weathering front in the core sediments, suggesting that they preserve an unweathered magnetic signature. We present results of preliminary comparison between the magnetic signals preserved in core sediments and the same sediments exposed as outcrops using detailed measurements of low-field magnetic susceptibility, frequency dependence of susceptibility, isothermal remanent magnetization (IRM), and anhysteretic remanent magnetization (ARM). We explore the implications of surficial weathering for environmental magnetism, including the application of magnetic paleoprecipitation proxies calibrated using modern soils to more ancient paleosols.

  5. Comparison of 20 nm silver nanoparticles synthesized with and without a gold core: Structure, dissolution in cell culture media, and biological impact on macrophages.

    PubMed

    Munusamy, Prabhakaran; Wang, Chongmin; Engelhard, Mark H; Baer, Donald R; Smith, Jordan N; Liu, Chongxuan; Kodali, Vamsi; Thrall, Brian D; Chen, Shu; Porter, Alexandra E; Ryan, Mary P

    2015-09-15

    Widespread use of silver nanoparticles raises questions of environmental and biological impact. Many synthesis approaches are used to produce pure silver and silver-shell gold-core particles optimized for specific applications. Since both nanoparticles and silver dissolved from the particles may impact the biological response, it is important to understand the physicochemical characteristics along with the biological impact of nanoparticles produced by different processes. The authors have examined the structure, dissolution, and impact of particle exposure to macrophage cells of two 20 nm silver particles synthesized in different ways, which have different internal structures. The structures were examined by electron microscopy and dissolution measured in Rosewell Park Memorial Institute media with 10% fetal bovine serum. Cytotoxicity and oxidative stress were used to measure biological impact on RAW 264.7 macrophage cells. The particles were polycrystalline, but 20 nm particles grown on gold seed particles had smaller crystallite size with many high-energy grain boundaries and defects, and an apparent higher solubility than 20 nm pure silver particles. Greater oxidative stress and cytotoxicity were observed for 20 nm particles containing the Au core than for 20 nm pure silver particles. A simple dissolution model described the time variation of particle size and dissolved silver for particle loadings larger than 9 μg/ml for the 24-h period characteristic of many in-vitro studies.

  6. Comparison of 20 nm silver nanoparticles synthesized with and without a gold core: Structure, dissolution in cell culture media, and biological impact on macrophages

    PubMed Central

    Munusamy, Prabhakaran; Wang, Chongmin; Engelhard, Mark H.; Baer, Donald R.; Smith, Jordan N.; Liu, Chongxuan; Kodali, Vamsi; Thrall, Brian D.; Chen, Shu; Porter, Alexandra E.; Ryan, Mary P.

    2015-01-01

    Widespread use of silver nanoparticles raises questions of environmental and biological impact. Many synthesis approaches are used to produce pure silver and silver-shell gold-core particles optimized for specific applications. Since both nanoparticles and silver dissolved from the particles may impact the biological response, it is important to understand the physicochemical characteristics along with the biological impact of nanoparticles produced by different processes. The authors have examined the structure, dissolution, and impact of particle exposure to macrophage cells of two 20 nm silver particles synthesized in different ways, which have different internal structures. The structures were examined by electron microscopy and dissolution measured in Rosewell Park Memorial Institute media with 10% fetal bovine serum. Cytotoxicity and oxidative stress were used to measure biological impact on RAW 264.7 macrophage cells. The particles were polycrystalline, but 20 nm particles grown on gold seed particles had smaller crystallite size with many high-energy grain boundaries and defects, and an apparent higher solubility than 20 nm pure silver particles. Greater oxidative stress and cytotoxicity were observed for 20 nm particles containing the Au core than for 20 nm pure silver particles. A simple dissolution model described the time variation of particle size and dissolved silver for particle loadings larger than 9 μg/ml for the 24-h period characteristic of many in-vitro studies. PMID:26178265

  7. Impact of climate fluctuations on deposition of DDT and hexachlorocyclohexane in mountain glaciers: evidence from ice core records.

    PubMed

    Wang, Xiaoping; Gong, Ping; Zhang, Qianggong; Yao, Tandong

    2010-02-01

    How do climate fluctuations affect DDT and hexachlorocyclohexane (HCH) distribution in the global scale? In this study, the interactions between climate variations and depositions of DDT and HCH in ice cores from Mt. Everest (the Tibetan Plateau), Mt. Muztagata (the eastern Pamirs) and the Rocky Mountains were investigated. All data regarding DDT/HCH deposition were obtained from the published results. Concentrations of DDT and HCH in an ice core from Mt. Everest were associated with the El Nino-Southern Oscillation. Concentrations of DDT in an ice core from Mt. Muztagata were significantly correlated with the Siberia High pattern. Concentrations of HCH in an ice core from Snow Dome of the Rocky Mountains responded to the North Atlantic Oscillation. These associations suggested that there are some linkages between climate variations and the global distribution of persistent organic pollutants.

  8. Quantifying the Impact of Nanoparticle Coatings and Non-uniformities on XPS Analysis: Gold/silver Core-shell Nanoparticles

    SciTech Connect

    Wang, Yung-Chen Andrew; Engelhard, Mark H.; Baer, Donald R.; Castner, David G.

    2016-03-07

    Abstract or short description: Spectral modeling of photoelectrons can serve as a valuable tool when combined with X-ray photoelectron spectroscopy (XPS) analysis. Herein, a new version of the NIST Simulation of Electron Spectra for Surface Analysis (SESSA 2.0) software, capable of directly simulating spherical multilayer NPs, was applied to model citrate stabilized Au/Ag-core/shell nanoparticles (NPs). The NPs were characterized using XPS and scanning transmission electron microscopy (STEM) to determine the composition and morphology of the NPs. The Au/Ag-core/shell NPs were observed to be polydispersed in size, non-circular, and contain off-centered Au-cores. Using the average NP dimensions determined from STEM analysis, SESSA spectral modeling indicated that washed Au/Ag-core shell NPs were stabilized with a 0.8 nm l

  9. Characterization of the log lithology of cores LB-07A and LB-08A of the Bosumtwi impact structure by using the anisotropy of magnetic susceptibility

    NASA Astrophysics Data System (ADS)

    Schell, Christina; Schleifer, Norbert; Elbra, Tiiu

    Petrophysical data are commonly used for the discrimination of different lithologies, as the variation in mineralogy, texture, and porosity is accompanied by varying physical properties. A special field of investigation is the analysis of the directional dependence (anisotropy) of the petrophysical properties, which can provide further information on the characteristics of the lithologies, due to the fact that this parameter is different in the various rock-forming and rockchanging processes, e.g., deformation or sedimentation. To characterize the rocks in drill cores LB-07A and LB-08A, which were drilled into the deep crater moat and central uplift of the Bosumtwi impact structure, Ghana, samples were taken for the study of petrophysical properties. In the present work the magnetic properties of these samples were determined in the laboratory. The results are discussed in relation to the various lithologies represented by this sample suite. The shape and degree of magnetic anisotropy, in combination with the magnetic susceptibility, proved useful in distinguishing between the different lithologies present in the drill cores (polymict lithic breccia, suevite, shale component, and meta-graywacke). It was possible to correlate layers of high (shale component), ntermediate (graywacke, polymict lithic breccia), and low (suevite) anisotropy degree with the lithostratigraphic sequences determined for cores LB-07A and LB-08A. The shape of the anisotropy showed that foliation is most dominant within the shale component, whereas lineation is more pronounced in the meta-graywacke and polymict lithic breccia. An overall increase of the anisotropy degree was observed from core LB-07A towards core LB-08A. Thus magnetic anisotropy data provide a useful contribution towards an improved petrophysical characterization of the lithostratigraphic sequences in drillcores from the Bosumtwi impact structure.

  10. Megablocks and melt pockets in the Chesapeake Bay impact structure constrained by magnetic field measurements and properties of the Eyreville and Cape Charles cores

    USGS Publications Warehouse

    Shah, A.K.; Daniels, D.L.; Kontny, A.; Brozena, J.

    2009-01-01

    We use magnetic susceptibility and remanent magnetization measurements of the Eyreville and Cape Charles cores 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 core 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 core 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 melt 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 core, 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.

  11. 10Be content in clasts from fallout suevitic breccia in drill cores from the Bosumtwi impact crater, Ghana: Clues to preimpact target distribution

    NASA Astrophysics Data System (ADS)

    Losiak, Anna; Wild, Eva Maria; Michlmayr, Leonard; Koeberl, Christian

    2014-03-01

    Rocks from drill cores LB-07A (crater fill) and LB-08A (central uplift) into the Bosumtwi impact crater, Ghana, were analyzed for the presence of the cosmogenic radionuclide 10Be. The aim of the study was to determine the extent to which target rocks of various depths were mixed during the formation of the crater-filling breccia, and also to detect meteoric water infiltration within the impactite layer. 10Be abundances above background were found in two (out of 24) samples from the LB-07A core, and in none of five samples from the LB-08A core. After excluding other possible explanations for an elevated 10Be signal, we conclude that it is most probably due to a preimpact origin of those clasts from target rocks close to the surface. Our results suggest that in-crater breccias were well mixed during the impact cratering process. In addition, the lack of a 10Be signal within the rocks located very close to the lake sediment-impactite boundary suggests that infiltration of meteoric water below the postimpact crater floor was limited. This may suggest that the infiltration of the meteoric water within the crater takes place not through the aerial pore-space, but rather through a localized system of fractures.

  12. Impact of hepatitis C virus core mutations on the response to interferon-based treatment in chronic hepatitis C

    PubMed Central

    Sultana, Camelia; Oprişan, Gabriela; Teleman, Monica Delia; Dinu, Sorin; Oprea, Cristiana; Voiculescu, Mihai; Ruta, Simona

    2016-01-01

    AIM To determine whether hepatitis C virus (HCV) core substitutions play a role in the response to interferon-based treatment in Caucasian patients. METHODS One hundred eight HCV chronically infected patients initiating treatment with pegylated IFN plus ribavirin for 48 wk were tested for baseline substitutions at codons 70 and 91 of the viral core protein (BigDye Terminator vers.3.1, Applied Biosystems,) and for genetic polymorphisms in host IL28B gene rs12979860 (Custom TaqMan 5' allelic discrimination assay; Applied Biosystems). RESULTS Of the patients, all were infected with HCV genotype 1b, 44.4% had low baseline HCV viral load, and 37.9% had mild/moderate fibrosis. Only 38.9% achieved therapeutic success, defined as sustained virological response (SVR). Eighty-eight percent of the patients presented at least one substitution at core position 70 (R70Q/H) or/and position 91 (L91M). The favorable IL28B CC polymorphism was detected in only 17.6% of the patients. In the univariate analysis, young age (P < 0.001), urban residence (P = 0.004), IL28B CC genotype (P < 0.001), absence of core mutations (P = 0.005), achievement of rapid virologic response (P < 0.001) and early virological response (P < 0.001) were significantly correlated with SVR. A multivariate analysis revealed three independent predictors of therapeutic success: young age (P < 0.001), absence of core substitutions (P = 0.04) and IL28B CC genotype (P < 0.001); the model correctly classified 75.9% of SVR cases with a positive predictive value of 80.7%. CONCLUSION HCV core mutations can help distinguish between patients who can still benefit from the affordable IFN-based therapy from those who must be treated with DAAs to prevent the evolution towards end-stage liver disease. PMID:27729747

  13. Partitioning of Cr, V, and Mn between mantles and cores of differentiated planetesimals - Implications for giant impact hypothesis of lunar origin

    SciTech Connect

    Ringwood, A.E.; Kato, T.; Hibberson, W.; Ware, N. )

    1991-01-01

    The partition coefficients of Cr, V, and Mn between metallic Fe and the mineral phases present in the mantle of a giant planetesimal have been determined in the 1500-2000 C range at 3-25 GPa, in order to ascertain whether the formation of an Fe core within a differentiated giant planetesimal could have caused depletions of Cr, V, and Mn in the Mars-sized planetesimal hypothesized as the basis for lunar formation after impact with the earth. The results obtained indicate that the formation of such an Fe core would have led to no such depletion; Cr, V, and Mn are depleted relative to Mg in the earth mantle to a degree comparable to the lunar depletion factor, suggesting that the protolunar material was primarily derived from the earth's mantle. 36 refs.

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

    USGS Publications Warehouse

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

    2009-01-01

    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

  15. Biocompatible long-sustained release oil-core polyelectrolyte nanocarriers: From controlling physical state and stability to biological impact.

    PubMed

    Szczepanowicz, Krzysztof; Bazylińska, Urszula; Pietkiewicz, Jadwiga; Szyk-Warszyńska, Lilianna; Wilk, Kazimiera A; Warszyński, Piotr

    2015-08-01

    It has been generally expected that the most applicable drug delivery system (DDS) should be biodegradable, biocompatible and with incidental adverse effects. Among many micellar aggregates and their mediated polymeric systems, polyelectrolyte oil-core nanocarriers have been found to successfully encapsulate hydrophobic drugs in order to target cells and avoid drug degradation and toxicity as well as to improve drug efficacy, its stability, and better intracellular penetration. This paper reviews recent developments in the formation of polyelectrolyte oil-core nanocarriers by subsequent multilayer adsorption at micellar structures, their imaging, physical state and stability, drug encapsulation and applications, in vitro release profiles and in vitro biological evaluation (cellular uptake and internalization, biocompatibility). We summarize the recent results concerning polyelectrolyte/surfactant interactions at interfaces, fundamental to understand the mechanisms of formation of stable polyelectrolyte layered structures on liquid cores. The fabrication of emulsion droplets stabilized by synergetic surfactant/polyelectrolyte complexes, properties, and potential applications of each type of polyelectrolyte oil-core nanocarriers, including stealth nanocapsules with pegylated shell, are discussed and evaluated.

  16. The Impact of the Common Core State Standards Initiative on Math ACT Scores of West Tennessee High School Students

    ERIC Educational Resources Information Center

    Hamilton, Kirkland D.

    2015-01-01

    The Common Core State Standards (CCSS) initiative is the latest effort by educational leaders to improve educational outcomes of American students. The standards are intended to bring uniformity in educational content of what is being taught in schools across the nation in order to promote rigor and academic portability. Proponents claimed the new…

  17. Natural and Anthropogenic Impacts on the Stable Isotopes of Nitrogen and Oxygen of Ice-Core Nitrate

    NASA Astrophysics Data System (ADS)

    Walters, W.; Michalski, G. M.

    2013-12-01

    The stable isotopes of nitrogen and oxygen of the Ross Ice Drainage System (RIDS) ice-core nitrate were measured in approximately 2-3 year time resolution using a Delta V Isotope Ratio Mass Spectrometer (IRMS). The nitrogen isotope variation (δ15N) and the mass-independent fractionation of oxygen (Δ17O = δ17O - 0.52*δ18O) yield a detailed picture of the changes in the global nitrogen cycling and the shift in the oxidation capacity of the atmosphere in response to natural and anthropogenic induced climate change. This is one of the few studies on stable isotopes of ice-core nitrate for time periods prior to the 1800's and will increase our understanding of the oxidation feedbacks of the atmosphere in response to volcanic events, the Little Ice Age, the Maunder Minimum, and anthropogenic emissions in the Southern Hemisphere.

  18. Impact of post-manipulation corrective core exercises on the spinal deformation and lumbar strength in golfers: a case study

    PubMed Central

    Shin, Chul-ho; Kim, Minjeong; Park, Gi Duck

    2015-01-01

    [Purpose] This study examined spinal shape in professional golfers with chronic back pain, and analyzed the effects of a 4-week regimen of semi-weekly manipulation and corrective core exercises on spinal shape. [Subjects] Two golfers with chronic back pain. [Methods] The pelvis and spinal vertebrae were corrected using the Thompson “drop” technique. Angle and force were adjusted to place the pelvis, lumbar spine, and thoracic vertebrae in neutral position. The technique was applied twice weekly after muscle massage in the back and pelvic areas. The golfers performed corrective, warmup stretching exercises, followed by squats on an unstable surface using the Togu ball. They then used a gym ball for repetitions of hip rotation, upper trunk extension, sit-ups, and pelvic anterior-posterior, pelvic left-right, and trunk flexion-extension exercises. The session ended with cycling as a cool-down exercise. Each session lasted 60 minutes. [Results] The difference in height was measured on the left and right sides of the pelvic bone. The pelvic tilt changed significantly in both participants after the 4-week program. [Conclusion] In golfers, core muscles are critical and are closely related to spinal deformation. Core strengthening and spinal correction play a pivotal role in the correction of spinal deformation. PMID:26504350

  19. Impact of post-manipulation corrective core exercises on the spinal deformation and lumbar strength in golfers: a case study.

    PubMed

    Shin, Chul-Ho; Kim, Minjeong; Park, Gi Duck

    2015-09-01

    [Purpose] This study examined spinal shape in professional golfers with chronic back pain, and analyzed the effects of a 4-week regimen of semi-weekly manipulation and corrective core exercises on spinal shape. [Subjects] Two golfers with chronic back pain. [Methods] The pelvis and spinal vertebrae were corrected using the Thompson "drop" technique. Angle and force were adjusted to place the pelvis, lumbar spine, and thoracic vertebrae in neutral position. The technique was applied twice weekly after muscle massage in the back and pelvic areas. The golfers performed corrective, warmup stretching exercises, followed by squats on an unstable surface using the Togu ball. They then used a gym ball for repetitions of hip rotation, upper trunk extension, sit-ups, and pelvic anterior-posterior, pelvic left-right, and trunk flexion-extension exercises. The session ended with cycling as a cool-down exercise. Each session lasted 60 minutes. [Results] The difference in height was measured on the left and right sides of the pelvic bone. The pelvic tilt changed significantly in both participants after the 4-week program. [Conclusion] In golfers, core muscles are critical and are closely related to spinal deformation. Core strengthening and spinal correction play a pivotal role in the correction of spinal deformation.

  20. Nutrient loss with runoff from fairway turf: an evaluation of core cultivation practices and their environmental impact.

    PubMed

    Rice, Pamela J; Horgan, Brian P

    2011-11-01

    The presence of excess nutrients in surface waters can result in undesirable environmental and economic consequences, including nuisance algal blooms and eutrophication. Fertilizer use in highly managed turf systems has raised questions concerning the contribution of nutrients to surrounding surface waters. Experiments were designed to quantify phosphorus and nitrogen transport with runoff from turf plots maintained as a golf course fairway to identify which cultural practice, solid tine (ST) or hollow tine (HT) core cultivation, maximized phosphorus and nitrogen retention at the site of fertilizer application. Simulated precipitation and collection of resulting runoff were completed 26 ± 13 h following granular fertilizer application (18-3-18: N-P₂O₅-K₂O) and 63 d and 2 d following core cultivation. Runoff volumes were reduced in fairway turf plots aerated with HT relative to ST (63 d: 10%, 2 d: 55% reduction). Analysis of the runoff revealed a reduction in soluble phosphorus, ammonium nitrogen, and nitrate nitrogen losses with runoff from plots managed with HT; a 5 to 27% reduction after 63 d; and a 39 to 77% reduction at 2 d. Golf course runoff-to-surface water scenarios were used to calculate estimated environmental concentrations (EECs) of nitrogen and phosphorus in surface water receiving runoff from turf managed with ST or HT core cultivation. Surface water concentrations of phosphorus remained above the U.S. Environmental Protection Agency's water quality criteria to limit eutrophication, with the exception of concentrations associated with HT core cultivation at 2 d. Regardless of management practice (ST or HT) and time between core cultivation and runoff (63 d or 2 d), all EECs of nitrogen were below levels associated with increased algal growth. Understanding nutrient transport with runoff and identifying strategies that reduce off-site transport will increase their effectiveness at intended sites of application and

  1. Two Extreme Climate Events of the Last 1000 Years Recorded in Himalayan and Andean Ice Cores: Impacts on Humans

    NASA Astrophysics Data System (ADS)

    Thompson, L. G.; Mosley-Thompson, E. S.; Davis, M. E.; Kenny, D. V.; Lin, P.

    2013-12-01

    In the last few decades numerous studies have linked pandemic influenza, cholera, malaria, and viral pneumonia, as well as droughts, famines and global crises, to the El Niño-Southern Oscillation (ENSO). Two annually resolved ice core records, one from Dasuopu Glacier in the Himalaya and one from the Quelccaya Ice Cap in the tropical Peruvian Andes provide an opportunity to investigate these relationships on opposite sides of the Pacific Basin for the last 1000 years. The Dasuopu record provides an annual history from 1440 to 1997 CE and a decadally resolved record from 1000 to 1440 CE while the Quelccaya ice core provides annual resolution over the last 1000 years. Major ENSO events are often recorded in the oxygen isotope, insoluble dust, and chemical records from these cores. Here we investigate outbreaks of diseases, famines and global crises during two of the largest events recorded in the chemistry of these cores, particularly large peaks in the concentrations of chloride (Cl-) and fluoride (Fl-). One event is centered on 1789 to 1800 CE and the second begins abruptly in 1345 and tapers off after 1360 CE. These Cl- and F- peaks represent major droughts and reflect the abundance of continental atmospheric dust, derived in part from dried lake beds in drought stricken regions upwind of the core sites. For Dasuopu the likely sources are in India while for Quelccaya the sources would be the Andean Altiplano. Both regions are subject to drought conditions during the El Niño phase of the ENSO cycle. These two events persist longer (10 to 15 years) than today's typical ENSO events in the Pacific Ocean Basin. The 1789 to 1800 CE event was associated with a very strong El Niño event and was coincidental with the Boji Bara famine resulting from extended droughts that led to over 600,000 deaths in central India by 1792. Similarly extensive droughts are documented in Central and South America. Likewise, the 1345 to 1360 CE event, although poorly documented

  2. Pore-water chemistry from the ICDP-USGS core hole in the Chesapeake Bay impact structure-Implications for paleohydrology, microbial habitat, and water resources

    USGS Publications Warehouse

    Sanford, W.E.; Voytek, M.A.; Powars, D.S.; Jones, B.F.; Cozzarelli, I.M.; Cockell, C.S.; Eganhouse, R.P.

    2009-01-01

    We investigated the groundwater system of the Chesapeake Bay impact structure by analyzing the pore-water chemistry in cores taken from a 1766-m-deep drill hole 10 km north of Cape Charles, Virginia. Pore water was extracted using high-speed centrifuges from over 100 cores sampled from a 1300 m section of the drill hole. The pore-water samples were analyzed for major cations and anions, stable isotopes of water and sulfate, dissolved and total carbon, and bioavailable iron. The results reveal a broad transition between freshwater and saline water from 100 to 500 m depth in the postimpact sediment section, and an underlying synimpact section that is almost entirely filled with brine. The presence of brine in the lowermost postimpact section and the trend in dissolved chloride with depth suggest a transport process dominated by molecular diffusion and slow, compaction-driven, upward flow. Major ion results indicate residual effects of diagenesis from heating, and a pre-impact origin for the brine. High levels of dissolved organic carbon (6-95 mg/L) and the distribution of electron acceptors indicate an environment that may be favorable for microbial activity throughout the drilled section. The concentration and extent of the brine is much greater than had previously been observed, suggesting that its occurrence may be common in the inner crater. However, groundwater-flow conditions in the structure may reduce the saltwater-intrusion hazard associated with the brine. ?? 2009 The Geological Society of America.

  3. Strontium and oxygen isotope study of M-1, M-3 and M-4 drill core samples from the Manson impact structure, Iowa: Comparison with Haitian K-T impact glasses

    NASA Technical Reports Server (NTRS)

    Blum, Joel D.; Chamberlain, C. Page; Hingston, Michael P.; Koeberl, Christian

    1993-01-01

    Strontium and oxygen isotope analyses were performed on 8 samples from the M-1, M-3, and M-4 cores recently drilled at the Manson impact structure. The samples were three elastic sedimentary rocks (of probable Cretaceous age) which occurred as clasts within the sedimentary clast breccia, two samples of crystalline rock breccia matrix, and three samples of dolomite and limestone. The Sr-87/Sr-86 (corrected to 65 Ma) ratios were much higher than those in impact glasses from the Haitian Cretaceous-Tertiary (K-T) boundary. Isotope mixing calculations demonstrate that neither the silicate or carbonate rocks analyzed from the Manson crater, or mixtures of these rocks are appropriate source materials for the Haitian impact glasses. However, the Sr-87/Sr-86 (65Ma) ratio and delta O-18 value of the Ca-rich Haitian glasses are well reproduced by mixtures of Si-rich Haitian glass with platform carbonate of K-T age.

  4. Geologic columns for the ICDP-USGS Eyreville A and B cores, Chesapeake Bay impact structure: Sediment-clast breccias, 1096 to 444 m depth

    USGS Publications Warehouse

    Edwards, L.E.; Powars, D.S.; Gohn, G.S.; Dypvik, H.

    2009-01-01

    The Eyreville A and B cores, recovered from the "moat" of the Chesapeake Bay impact structure, provide a thick section of sediment-clast breccias and minor stratified sediments from 1095.74 to 443.90 m. This paper discusses the components of these breccias, presents a geologic column and descriptive lithologic framework for them, and formalizes the Exmore Formation. From 1095.74 to ??867 m, the cores consist of nonmarine sediment boulders and sand (rare blocks up to 15.3 m intersected diameter). A sharp contact in both cores at ??867 m marks the lowest clayey, silty, glauconitic quartz sand that constitutes the base of the Exmore Formation and its lower diamicton member. Here, material derived from the upper sediment target layers, as well as some impact ejecta, occurs. The block-dominated member of the Exmore Formation, from ??855-618.23 m, consists of nonmarine sediment blocks and boulders (up to 45.5 m) that are juxtaposed complexly. Blocks of oxidized clay are an important component. Above 618.23 m, which is the base of the informal upper diamicton member of the Exmore Formation, the glauconitic matrix is a consistent component in diamicton layers between nonmarine sediment clasts that decrease in size upward in the section. Crystalline-rock clasts are not randomly distributed but rather form local concentrations. The upper part of the Exmore Formation consists of crudely fining-upward sandy packages capped by laminated silt and clay. The overlap interval of Eyreville A and B (940-??760 m) allows recognition of local similarities and differences in the breccias. ?? 2009 The Geological Society of America.

  5. Estimates of the hydrologic impact of drilling water on core samples taken from partially saturated densely welded tuff

    SciTech Connect

    Buscheck, T.A.; Nitao, J.J.

    1987-09-01

    The purpose of this work is to determine the extent to which drill water might be expected to be imbibed by core samples taken from densely welded tuff. In a related experimental study conducted in G-Tunnel, drill water imbibition by the core samples was observed to be minimal. Calculations were carried out with the TOUGH code with the intent of corroborating the imbibition observations. Due to the absence of hydrologic data pertaining directly to G-Tunnel welded tuff, it was necessary to apply data from a similar formation. Because the moisture retention curve was not available for imbibition conditions, the drainage curve was applied to the model. The poor agreement between the observed and calculated imbibition data is attributed primarily to the inappropriateness of the drainage curve. Also significant is the value of absolute permeability (k) assumed in the model. Provided that the semi-log plot of the drainage and imbibition moisture retention curves are parallel within the saturation range of interest, a simple relationship exists between the moisture retention curve, k, and porosity ({phi}) which are assumed in the model and their actual values. If k and {phi} are known, we define the hysteresis factor {lambda} to be the ratio of the imbibition and drainage suction pressures for any saturation within the range of interest. If k and {phi} are unknown, {lambda} also accounts for the uncertainties in their values. Both the experimental and modeling studies show that drill water imbibition by the core has a minimal effect on its saturation state. 22 refs., 6 figs., 2 tabs.

  6. Scoping assessments of ATF impact on late-stage accident progression including molten core-concrete interaction

    NASA Astrophysics Data System (ADS)

    Farmer, M. T.; Leibowitz, L.; Terrani, K. A.; Robb, K. R.

    2014-05-01

    Simple scoping models that can be used to evaluate ATF performance under severe accident conditions have been developed. The methodology provides a fundamental technical basis (a.k.a. metric) based on the thermodynamic boundary for evaluating performance relative to that of traditional Zr-based claddings. The initial focus in this study was on UO2 fuel with the advanced claddings 310 SS, D9, FeCrAl, and SiC. The evaluation considered only energy release with concurrent combustible gas production from fuel-cladding-coolant interactions and, separately, molten core-concrete interactions at high temperatures. Other important phenomenological effects that can influence the rate and extent of cladding decomposition (e.g., eutectic interactions, degradation of other core constituents) were not addressed. For the cladding types addressed, potential combustible gas production under both in-vessel and ex-vessel conditions was similar to that for Zr. However, exothermic energy release from cladding oxidation was substantially less for iron-based alloys (by at least a factor of 4), and modestly less (by ∼20%) for SiC. Data on SiC-clad UO2 fuel performance under severe accident conditions are sparse in the literature; thus, assumptions on the nature of the cladding decomposition process were made in order to perform this initial screening evaluation. Experimental data for this system under severe accident conditions is needed for a proper evaluation and comparison to iron-based claddings.

  7. A qualitative analysis of the impact of the reform of the College of Science undergraduate core curriculum at State University

    NASA Astrophysics Data System (ADS)

    Ballotti, Dean

    The Dean of the College of Science at State University, a large public Midwestern research university, in a memo to the faculty and staff initiated what he called a "review" of the undergraduate science core curriculum. He formed a task force that was to investigate on three issues; a reassessment of the undergraduate core curriculum, the recruitment and retention of qualified undergraduate students with an emphasis on diversity, and strategies that would address these issues. The age of the curriculum, 40 years since the last significant change, was an important factor in the review of the curriculum. This qualitative study seeks to understand how a group of four administrators and five faculty, all from the College of Science, participated in the task force, perceived the old curriculum, and perceived the changes made and the resulting new curriculum. They were also asked to rank both the prior and new curricula. As part of an ongoing theme in higher education they were also asked if they thought the changes made to the curriculum qualified as reform and why or why not. This resulted in a discussion of what a reform might look like at State University and ultimately a definition of reform.

  8. Impact of kenaf (Hibiscus cannabinus L.) leaf, bark, and core extracts on germination of five plant species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The chemical interaction between plants, which is referred to as allelopathy, may result in the inhibition of plant growth and development. The objective of this research was to determine the impact of kenaf (Hibiscus cannabinus L.) plant extracts on the germination and post-germination development ...

  9. Is the transition impact to post-impact rock complete? Some remarks based on XRF scanning, electron microprobe, and thin section analyses of the Yaxcopoil-1 core in the Chicxulub crater

    NASA Astrophysics Data System (ADS)

    Smit, J.; van der Gaast, S.; Lustenhouwer, W.

    2004-07-01

    The transition from impact to post-impact rocks in the Yaxcopoil-1 (Yax-1) core is marked by a 2 cm-thick clay layer characterized by dissolution features. The clay overlies a 9 cm-thick hardground, overlying a 66 cm-thick crossbedded unit, consisting of dolomite sandstone alternating with thin micro-conglomerate layers with litho- and bioclasts and the altered remains of impact glass, now smectite. The micro-conglomerates mark erosion surfaces. Microprobe and backscatter SEM analysis of the dolomite rhombs show an early diagenetic, complex-zoned, idiomorphic overgrowth, with Mn-rich zones, possibly formed by hot fluids related to cooling melt sheet in the crater. The pore spaces are filled with several generations of coelestite, barite, K-feldpar, and sparry calcite. XRF core scanning analysis detected high Mn values in the crossbedded sediments but no anomalous enrichment of the siderophile elements Cr, Co, Fe, and Ni in the clay layer. Shocked quartz occurs in the crossbedded unit but is absent in the clay layer. The basal Paleocene marls are strongly dissolved and do not contain a basal Paleocene fauna. The presence of a hardground, the lack of siderophile elements, shocked quartz, or Ni-rich spinels in the clay layer, and the absence of basal Paleocene biozones P0 and Pa all suggest that the top of the ejecta sequence and a significant part of the lower Paleocene is missing. Due to the high energy sedimentation infill, a hiatus at the top of the impactite is not unexpected, but there is nothing in the biostratigraphy, geochemistry, and petrology of the Yax- 1 core that can be used to argue against the synchroneity of the end-Cretaceous mass-extinctions and the Chicxulub crater.

  10. ON THE IMPACT OF THREE DIMENSIONS IN SIMULATIONS OF NEUTRINO-DRIVEN CORE-COLLAPSE SUPERNOVA EXPLOSIONS

    SciTech Connect

    Couch, Sean M.

    2013-09-20

    We present one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) hydrodynamical simulations of core-collapse supernovae including a parameterized neutrino heating and cooling scheme in order to investigate the critical core neutrino luminosity (L{sub crit}) required for explosion. In contrast to some previous works, we find that 3D simulations explode later than 2D simulations, and that L{sub crit} at fixed mass accretion rate is somewhat higher in three dimensions than in two dimensions. We find, however, that in two dimensions L{sub crit} increases as the numerical resolution of the simulation increases. In contrast to some previous works, we argue that the average entropy of the gain region is in fact not a good indicator of explosion but is rather a reflection of the greater mass in the gain region in two dimensions. We compare our simulations to semi-analytic explosion criteria and examine the nature of the convective motions in two dimensions and three dimensions. We discuss the balance between neutrino-driven buoyancy and drag forces. In particular, we show that the drag force will be proportional to a buoyant plume's surface area while the buoyant force is proportional to a plume's volume and, therefore, plumes with greater volume-to-surface-area ratios will rise more quickly. We show that buoyant plumes in two dimensions are inherently larger, with greater volume-to-surface-area ratios, than plumes in three dimensions. In the scenario that the supernova shock expansion is dominated by neutrino-driven buoyancy, this balance between buoyancy and drag forces may explain why 3D simulations explode later than 2D simulations and why L{sub crit} increases with resolution. Finally, we provide a comparison of our results with other calculations in the literature.

  11. Magnetic anomalies in the Imbrium and Schrödinger impact basins: Orbital evidence for persistence of the lunar core dynamo into the Imbrian epoch

    NASA Astrophysics Data System (ADS)

    Hood, L. L.; Spudis, P. D.

    2016-11-01

    Approximate maps of the lunar crustal magnetic field at low altitudes in the vicinities of the three Imbrian-aged impact basins, Orientale, Schrödinger, and Imbrium, have been constructed using Lunar Prospector and Kaguya orbital magnetometer data. Detectable anomalies are confirmed to be present well within the rims of Imbrium and Schrödinger. Anomalies in Schrödinger are asymmetrically distributed about the basin center, while a single isolated anomaly is most clearly detected within Imbrium northwest of Timocharis crater. The subsurface within these basins was heated to high temperatures at the time of impact and required long time periods (up to 1 Myr) to cool below the Curie temperature for metallic iron remanence carriers (1043 K). Therefore, consistent with laboratory analyses of returned samples, a steady, long-lived magnetizing field, i.e., a former core dynamo, is inferred to have existed when these basins formed. The asymmetrical distribution within Schrödinger suggests partial demagnetization by later volcanic activity when the dynamo field was much weaker or nonexistent. However, it remains true that anomalies within Imbrian-aged basins are much weaker than those within most Nectarian-aged basins. The virtual absence of anomalies within Orientale where impact melt rocks (the Maunder Formation) are exposed at the surface is difficult to explain unless the dynamo field was much weaker during the Imbrian period.

  12. ALMA Cycle 1 Observations of the HH46/47 Molecular Outflow: Structure, Entrainment, and Core Impact

    NASA Astrophysics Data System (ADS)

    Zhang, Yichen; Arce, Héctor G.; Mardones, Diego; Cabrit, Sylvie; Dunham, Michael M.; Garay, Guido; Noriega-Crespo, Alberto; Offner, Stella S. R.; Raga, Alejandro C.; Corder, Stuartt A.

    2016-12-01

    We present Atacama Large Millimeter/sub-millimeter Array Cycle 1 observations of the HH 46/47 molecular outflow using combined 12 m array and Atacama Compact Array observations. The improved angular resolution and sensitivity of our multi-line maps reveal structures that help us study the entrainment process in much more detail and allow us to obtain more precise estimates of outflow properties than in previous observations. We use {}13{{CO}} (1-0) and {{{C}}}18{{O}} (1-0) emission to correct for the {}12{{CO}} (1-0) optical depth to accurately estimate the outflow mass, momentum, and kinetic energy. This correction increases the estimates of the mass, momentum, and kinetic energy by factors of about 9, 5, and 2, respectively, with respect to estimates assuming optically thin emission. The new {}13{{CO}} and {{{C}}}18{{O}} data also allow us to trace denser and slower outflow material than that traced by the {}12{{CO}} maps, and they reveal an outflow cavity wall at very low velocities (as low as 0.2 {\\text{km s}}-1 with respect to the core’s central velocity). Adding the slower material traced only by {}13{{CO}} and {{{C}}}18{{O}}, there is another factor of three increase in the mass estimate and 50% increase in the momentum estimate. The estimated outflow properties indicate that the outflow is capable of dispersing the parent core within the typical lifetime of the embedded phase of a low-mass protostar and that it is responsible for a core-to-star efficiency of 1/4 to 1/3. We find that the outflow cavity wall is composed of multiple shells associated with a series of jet bow-shock events. Within about 3000 au of the protostar the {}13{{CO}} and {{{C}}}18{{O}} emission trace a circumstellar envelope with both rotation and infall motions, which we compare with a simple analytic model. The CS (2-1) emission reveals tentative evidence of a slowly moving rotating outflow, which we suggest is entrained not only poloidally but also toroidally by a disk wind that

  13. Multi-Group Formulation of the Temperature-Dependent Resonance Scattering Model and its Impact on Reactor Core Parameters

    SciTech Connect

    Ghrayeb, Shadi Z.; Ougouag, Abderrafi M.; Ouisloumen, Mohamed; Ivanov, Kostadin N.

    2014-01-01

    A multi-group formulation for the exact neutron elastic scattering kernel is developed. It incorporates the neutron up-scattering effects, stemming from lattice atoms thermal motion and accounts for it within the resulting effective nuclear cross-section data. The effects pertain essentially to resonant scattering off of heavy nuclei. The formulation, implemented into a standalone code, produces effective nuclear scattering data that are then supplied directly into the DRAGON lattice physics code where the effects on Doppler Reactivity and neutron flux are demonstrated. The correct accounting for the crystal lattice effects influences the estimated values for the probability of neutron absorption and scattering, which in turn affect the estimation of core reactivity and burnup characteristics. The results show an increase in values of Doppler temperature feedback coefficients up to -10% for UOX and MOX LWR fuels compared to the corresponding values derived using the traditional asymptotic elastic scattering kernel. This paper also summarizes the results done on this topic to date.

  14. CO2 Exsolution from CO2 Saturated Water: Core-Scale Experiments and Focus on Impacts of Pressure Variations.

    PubMed

    Xu, Ruina; Li, Rong; Ma, Jin; Jiang, Peixue

    2015-12-15

    For CO2 sequestration and utilization in the shallow reservoirs, reservoir pressure changes are due to the injection rate changing, a leakage event, and brine withdrawal for reservoir pressure balance. The amounts of exsolved CO2 which are influenced by the pressure reduction and the subsequent secondary imbibition process have a significant effect on the stability and capacity of CO2 sequestration and utilization. In this study, exsolution behavior of the CO2 has been studied experimentally using a core flooding system in combination with NMR/MRI equipment. Three series of pressure variation profiles, including depletion followed by imbibitions without or with repressurization and repetitive depletion and repressurization/imbibition cycles, were designed to investigate the exsolution responses for these complex pressure variation profiles. We found that the exsolved CO2 phase preferentially occupies the larger pores and exhibits a uniform spatial distribution. The mobility of CO2 is low during the imbibition process, and the residual trapping ratio is extraordinarily high. During the cyclic pressure variation process, the first cycle has the largest contribution to the amount of exsolved CO2. The low CO2 mobility implies a certain degree of self-sealing during a possible reservoir depletion.

  15. Properties, classification, and genetic interpretation of the allochthonous impact formations of the ICDP Chicxulub drill core YAX-1

    NASA Astrophysics Data System (ADS)

    Stöffler, D.; Hecht, L.; Kenkmann, T.; Schmitt, R. T.; Wittmann, A.

    2003-04-01

    The ICDP drilling Yaxcopoil-1 exposes 1510 m of impact-related lithologies. We report here and in related abstracts [1-3] on allochthonous impactites representing a complex layered sequence of polymict breccias, extremely rich in impact melt particles and rather poor in fine-grained matrix. This sequence can be subdivided into 6 units. Their whole rock chemistry reflects a mixture of crystalline rocks and Cretaceous carbonate rocks. The completely crystallized silicate "glass" occurs in discrete particles whereas carbonate melt forms exsolved inclusions in silicate melts and larger bodies of polycrystalline Mg-bearing calcite in unit 6. The stratigraphy, classification, and properties of the impactites are as follows: Unit 1 (Upper sorted suevite): 794.63 m, melt-rich, fine grained, clastic matrix; Unit 2 (Lower sorted suevite): 807.75 m, melt-rich, coarse grained, clastic matrix partly recrystallized, Unit 3 (Upper suevite): 823.25 m, melt rich, very coarse grained, recrystallized matrix; Unit 4 (Middle suevite): 846.09 m, melt rich, very coarse grained, recrystallized matrix; Unit 5 (Suevitic breccia with cataclastic melt rock): 861.06 m, suevitic melt agglomerate with monomictly brecciated melt bodies, coarse grained, crystallized matrix (remelted); Unit 6 (Lower suevite): 884.96 m, suevite with silicate and carbonate melt, very coarse grained; recrystallized matrix; Unit 7 (Cretaceous): 894.94-1510.97 m, displaced bedded carbonates and anhydrite, partially brecciated, with impact breccia dikes. The source material of the layered breccias, derived from the deepest excavation zone, was incorporated into the ejecta plume at a late stage when the bulk of the high rising plume had disappeared from the impact site [3] and distributed globally. The upper section (units 1-4) is interpreted as ballistic "fallout" material from the ejecta plume. The Lower Suevite (unit 6) represents ground surged material deposited as the first layer and then covered with laterally

  16. A young Moon-forming giant impact at 70-110 million years accompanied by late-stage mixing, core formation and degassing of the Earth.

    PubMed

    Halliday, Alex N

    2008-11-28

    New W isotope data for lunar metals demonstrate that the Moon formed late in isotopic equilibrium with the bulk silicate Earth (BSE). On this basis, lunar Sr isotope data are used to define the former composition of the Earth and hence the Rb-Sr age of the Moon, which is 4.48+/-0.02Ga, or 70-110Ma (million years) after the start of the Solar System. This age is significantly later than had been deduced from W isotopes based on model assumptions or isotopic effects now known to be cosmogenic. The Sr age is in excellent agreement with earlier estimates based on the time of lunar Pb loss and the age of the early lunar crust (4.46+/-0.04Ga). Similar ages for the BSE are recorded by xenon and lead-lead, providing evidence of catastrophic terrestrial degassing, atmospheric blow-off and significant late core formation accompanying the ca 100Ma giant impact. Agreement between the age of the Moon based on the Earth's Rb/Sr and the lead-lead age of the Moon is consistent with no major losses of moderately volatile elements from the Earth during the giant impact. The W isotopic composition of the BSE can be explained by end member models of (i) gradual accretion with a mean life of roughly 35Ma or (ii) rapid growth with a mean life of roughly 10Ma, followed by a significant hiatus prior to the giant impact. The former assumes that approximately 60 per cent of the incoming metal from impactors is added directly to the core during accretion. The latter includes complete mixing of all the impactor material into the BSE during accretion. The identical W isotopic composition of the Moon and the BSE limits the amount of material that can be added as a late veneer to the Earth after the giant impact to less than 0.3+/-0.3 per cent of ordinary chondrite or less than 0.5+/-0.6 per cent CI carbonaceous chondrite based on their known W isotopic compositions. Neither of these on their own is sufficient to explain the inventories of both refractory siderophiles such as platinum group

  17. Polar organic compounds in pore waters of the Chesapeake Bay impact structure, Eyreville core hole: Character of the dissolved organic carbon and comparison with drilling fluids

    USGS Publications Warehouse

    Rostad, C.E.; Sanford, W.E.

    2009-01-01

    Pore waters from the Chesapeake Bay impact structure cores recovered at Eyreville Farm, Northampton County, Virginia, were analyzed to characterize the dissolved organic carbon. After squeezing or centrifuging, a small volume of pore water, 100 ??L, was taken for analysis by electrospray ionization-mass spectrometry. Porewater samples were analyzed directly without filtration or fractionation, in positive and negative mode, for polar organic compounds. Spectra in both modes were dominated by low-molecular-weight ions. Negative mode had clusters of ions differing by -60 daltons, possibly due to increasing concentrations of inorganic salts. The numberaverage molecular weight and weight-average molecular weight values for the pore waters from the Chesapeake Bay impact structure are higher than those reported for other aquatic sources of natural dissolved organic carbon as determined by electrospray ionization-mass spectrometry. In order to address the question of whether drilling mud fluids may have contaminated the pore waters during sample collection, spectra from the pore waters were compared to spectra from drilling mud fluids. Ions indicative of drilling mud fluids were not found in spectra from the pore waters, indicating there was no detectable contamination, and highlighting the usefulness of this analytical technique for detecting potential contamination during sample collection. ?? 2009 The Geological Society of America.

  18. Tungsten divertor sourcing in DIII-D H-mode discharges and its impact on core impurity accumulation in different ELM regimes

    NASA Astrophysics Data System (ADS)

    Abrams, T.; Ding, R.; Guterl, J.; Briesemeister, A.; Unterberg, E. A.; Guo, H. Y.; Leonard, A. W.; Thomas, D. M.; McLean, A. G.; Victor, B.; Rudakov, D.; Grierson, B.; Watkins, J. G.; Elder, J. D.; Stangeby, P. C.

    2016-10-01

    Significant progress has been made understanding W sourcing during Type I ELMy H-mode on DIII-D using fast high-resolution measurements of W sourcing coupled with OEDGE/ERO and TRIM.SP modeling. ERO modeling of the inter-ELM phase, using a new OEDGE capability for charge state-resolved carbon ion fluxes and a material mixing model, shows measured W erosion is well explained by C- >W sputtering. Ion impact energies in the DIII-D divertor during ELMs, inferred from ratios of heat flux to ion flux, are 200-500 eV. Comparisons with TRIM.SP indicate C- >W sputtering dominates W sourcing during ELMs. This is in contrast to JET where ion impact energies are 3-5 keV during ELMs, predicted by the ``free streaming model,'' and D- >W sputtering strongly contributes to W sourcing. Fast measurements of W erosion dynamics during ELMs agree well with TRIM.SP-based sputtering models assuming C/W surface concentrations of 0.5-0.8 and a 2% C2+ ion flux fraction. Core W accumulation and SOL W density measurements made during the DIII-D high-Z tile array mini-campaign correlate with ELM frequency and W source rate. Supported by US DOE under DE-FC02-04ER54698.

  19. Electron-impact core excitation of SF6. I. S 2p, S 2s, and F 1s spectroscopy

    NASA Astrophysics Data System (ADS)

    Francis, James T.; Turci, Cássia C.; Tyliszczak, Tolek; de Souza, G. Gerson B.; Kosugi, Nobuhiro; Hitchcock, Adam P.

    1995-12-01

    Electron energy-loss spectra (EELS) of SF6 have been recorded in the region of S 2p, S 2s, and F 1s excitation, using both dipole and nondipole electron-scattering conditions. Impact energies between 700 and 3200 eV and scattering angles between 0° and 30° were used. Relative to dipole EELS or photoabsorption, there are large intensity redistributions in both the S 2p and S 2s spectra under nondipole conditions. In contrast, the F 1s spectrum is essentially the same in near-dipole and nondipole scattering regimes. A higher-order electric multiple S 2p spectra feature is observed at 181 eV. It has an unusual multipeaked line shape whose components are more closely spaced than the typical 1.15-eV S 2p spin-orbit splitting. It is attributed to the overlap of several quadrupole-coupled states, which are likely associated with the [S 2p(t1u)-1,t1u] configuration. Ab initio self-consistent field calculations for various open-shell S 2p excited states are used to assist spectral assignments.

  20. Yucatan Subsurface Stratigraphy from Geophysical Data, Well Logs and Core Analyses in the Chicxulub Impact Crater and Implications for Target Heterogeneities

    NASA Astrophysics Data System (ADS)

    Canales, I.; Fucugauchi, J. U.; Perez-Cruz, L. L.; Camargo, A. Z.; Perez-Cruz, G.

    2011-12-01

    Asymmetries in the geophysical signature of Chicxulub crater are being evaluated to investigate on effects of impact angle and trajectory and pre-existing target structural controls for final crater form. Early studies interpreted asymmetries in the gravity anomaly in the offshore sector to propose oblique either northwest- and northeast-directed trajectories. An oblique impact was correlated to the global ejecta distribution and enhanced environmental disturbance. In contrast, recent studies using marine seismic data and computer modeling have shown that crater asymmetries correlate with pre-existing undulations of the Cretaceous continental shelf, suggesting a structural control of target heterogeneities. Documentation of Yucatan subsurface stratigraphy has been limited by lack of outcrops of pre-Paleogene rocks. The extensive cover of platform carbonate rocks has not been affected by faulting or deformation and with no rivers cutting the carbonates, information comes mainly from the drilling programs and geophysical surveys. Here we revisit the subsurface stratigraphy in the crater area from the well log data and cores retrieved in the drilling projects and marine seismic reflection profiles. Other source of information being exploited comes from the impact breccias, which contain a sampling of disrupted target sequences, including crystalline basement and Mesozoic sediments. We analyze gravity and seismic data from the various exploration surveys, including multiple Pemex profiles in the platform and the Chicxulub experiments. Analyses of well log data and seismic profiles identify contacts for Lower Cretaceous, Cretaceous/Jurassic and K/Pg boundaries. Results show that the Cretaceous continental shelf was shallower on the south and southwest than on the east, with emerged areas in Quintana Roo and Belize. Mesozoic and upper Paleozoic sediments show variable thickness, possibly reflecting the crystalline basement regional structure. Paleozoic and Precambrian

  1. Comparison of clast frequency and size in the resurge deposits at the Chesapeake Bay impact structure (Eyreville A and Langley cores): Clues to the resurge process

    USGS Publications Warehouse

    Ormo, J.; Sturkell, E.; Horton, J.W.; Powars, D.S.; Edwards, L.E.

    2009-01-01

    Collapse and inward slumping of unconsolidated sedimentary strata expanded the Chesapeake Bay impact structure far beyond its central basement crater. During crater collapse, sediment-loaded water surged back to fill the crater. Here, we analyze clast frequency and granulometry of these resurge deposits in one core hole from the outermost part of the collapsed zone (i.e., Langley) as well as a core hole from the moat of the basement crater (i.e., Eyreville A). Comparisons of clast provenance and flow dynamics show that at both locations, there is a clear change in clast frequency and size between a lower unit, which we interpret to be dominated by slumped material, and an upper, water-transported unit, i.e., resurge deposit. The contribution of material to the resurge deposit was primarily controlled by stripping and erosion. This includes entrainment of fallback ejecta and sediments eroded from the surrounding seafloor, found to be dominant at Langley, and slumped material that covered the annular trough and basement crater, found to be dominant at Eyreville. Eyreville shows a higher content of crystalline clasts than Langley. There is equivocal evidence for an anti-resurge from a collapsing central water plume or, alternatively, a second resurge pulse, as well as a transition into oscillating resurge. The resurge material shows more of a debris-flow-like transport compared to resurge deposits at some other marine target craters, where the ratio of sediment to water has been relatively low. This result is likely a consequence of the combination of easily disaggregated host sediments and a relatively shallow target water depth. ?? 2009 The Geological Society of America.

  2. Potential of E.coli O157:H7 to grow on field-cored lettuce as impacted by postharvest storage time and temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A recent development in iceberg lettuce production is field coring where the outer leaves and the cores of the lettuce heads are removed at the time of harvesting in order to reduce shipping waste and maximize production yield. Using a coring knife contaminated with 2 x 105 cells of E. coli O157:H7,...

  3. Impacts of Asian dust storm associated with the stratosphere-to-troposphere transport in the spring of 2001 and 2002 on dust and tritium variations in Mount Wrangell ice core, Alaska

    NASA Astrophysics Data System (ADS)

    Yasunari, Teppei J.; Yamazaki, Koji

    The relation of interannual connection between Asian dust outbreaks and stratosphere-to-troposphere transport (STT) in spring was suggested by the dust and tritium variations in the Mount Wrangell ice core, Alaska in [Yasunari, T.J., Shiraiwa, T., Kanamori, S., Fujii, Y., Igarashi, M., Yamazaki, K., Benson, C.S., Hondoh, T., 2007. Intra-annual variations in atmospheric dust and tritium in the North Pacific region detected from an ice core from Mount Wrangell, Alaska. J. Geophys. Res., 112, D10208. doi: 10.1029/2006JD008121]. However, these impacts on the ice core site in each event scale have not been investigated. Hence, the present paper focuses on the material transport and deposition processes for further understanding these impacts on the ice core. The variations in dust and tritium concentrations in spring in an ice core taken at Mt. Wrangell, Alaska are explained by meteorological analysis and simulation of trajectories associated with Asian dust outbreaks and STT. Material transport and deposition at Mt. Wrangell are examined in two contrasting years (2001 and 2002). Dust and tritium concentrations both reached peak values in the early spring of 2002, while the dust peak occurred in early spring and the tritium peak occurred in late spring in 2001. Six severe East Asian transpacific dust storms over this period are modeled by forward trajectory and meteorologically analyzed. It is found that 5 of 6 events contributed to the ice core record in Alaska. Stratospheric air is also transported to the ice core site in most cases. Tritium deposition is found to have been suppressed in the cases of the 2001 dust storms due to lack of snowfall at appropriate times. Taken the detailed transport and deposition processes after the severe dust storms with atmospheric circulations into account, we can well explain spring dust and tritium variations in the Mount Wrangell ice core.

  4. Temporal trends of persistent organic pollutants in dated sediment cores: Chemical fingerprinting of the anthropogenic impacts in the Seine River basin, Paris.

    PubMed

    Lorgeoux, C; Moilleron, R; Gasperi, J; Ayrault, S; Bonté, P; Lefèvre, I; Tassin, B

    2016-01-15

    Persistent organic pollutants (POPs) were extensively produced and used throughout the last century. In the early 1980s, a rising concern on the environmental impact of these chemicals has led to the establishment of regulations and changes of use including bans. Long term monitoring of the environmental impacts of these emissions and regulations is a challenge because regular monitoring was not mandatory at the beginning of the first emissions. Moreover, the analytical methods have been strongly improved over the decades. To overcome the lack of monitoring and accurate data, sediment cores are powerful tools to construct contamination records. In this study, a high resolution record was constructed for four POPs families (13 polycyclic aromatic hydrocarbons (PAHs), 15 polychlorinated biphenyls (PCBs), 3 alkylphenols (APs) and 8 polybromodiphenyl ethers (PBDEs)) to establish their historical trends in a long-term urbanized and industrialized environment: the Seine River basin, France. These specific families were selected because they had different sources, uses and histories. The results showed concentrations up to 90 mg/kg for ∑PAHs, 2.3mg/kg for ∑PCB, 1.2mg/kg for ∑APs and 0.06 mg/kg for ∑PBDE. The vertical distribution profiles were different from one family to another and presented a good correlation with uses (e.g. transition from coal to natural gas for PAHs), and regulation implementation (e.g., AP ban after "OSPAR Convention" in 1992). The study of compounds distribution provided original information on sources, e.g. temporal variations in PAH uses. This study demonstrates the usefulness and accuracy of sedimentary archives in floodplain to assess the fate of POPs through time in continental hydrosystems. These first results give a comprehensive overview of the contamination in the Seine River basin downstream of Paris Megacity. They were in good agreement with previous studies dedicated to European areas and highlighted specificities of this basin

  5. The impact of the core transformation process on spirituality, symptom experience, and psychological maturity in a mixed age sample in India: a pilot study.

    PubMed

    Braganza, Dinesh; Piedmont, Ralph L

    2015-06-01

    Research indicates that spiritual and religious constructs have the potential to influence a broad range of outcomes such as health, well-being, and meaning, both positively and negatively. This study looked at the effect of an under studied psycho-spiritual approach, Core Transformation (CT), in reducing symptoms and promoting well-being. This study also examined whether the impact of CT would be moderated by age, with older participants evidencing better outcomes. Participants from an Indian convenience sample (N = 189) ranging in age from 18 to 65 (M = 34) received group training in CT and completed a battery of measures pretest and 4 weeks post-training, which included personality, spirituality, and psychosocial outcomes scales. Repeated-measures MANOVAs indicated significant improvements over time for both spirituality and symptom experience. Partial correlation analyses, controlling for the predictive effects of personality, reaffirmed the incremental validity of Spiritual Transcendence and religious variables in predicting symptom change and outcome ratings. CT did not appear to effect participants levels of psychological maturity. Age was not found to mediate any of these relationships, indicating the age universality of CT's therapeutic effects.

  6. 24. A CORE WORKER DISPLAYS THE CORE BOX AND CORES ...

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

    24. A CORE WORKER DISPLAYS THE CORE BOX AND CORES FOR A BRASS GATE VALVE BODY MADE ON A CORE BOX, CA. 1950. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  7. Dynamic Instabilities of Simulated Hurricane-like Vortices and Their Impacts on the Core Structure of Hurricanes. Part I: Dry Experiments.

    NASA Astrophysics Data System (ADS)

    Kwon, Young C.; Frank, William M.

    2005-11-01

    A series of numerical simulations of dry, axisymmetric hurricane-like vortices is performed to examine the growth of barotropic and baroclinic eddies and their potential impacts on hurricane core structure and intensity. The numerical experiments are performed using the fifth-generation Pennsylvania State University National Center for Atmospheric Research (PSU NCAR) Mesoscale Model (MM5) with a 6-km horizontal grid. To examine internal effects on the stability of vortices, all external forcings are eliminated. Axisymmetric vortices that resemble observed hurricane structures are constructed on an f plane, and the experiments are performed without moist and boundary layer processes.Three vortices are designed for this study. A balanced control vortex is built based on the results of a full-physics simulation of Hurricane Floyd (1999). Then, two other axisymmetric vortices, EXP-1 and EXP-2, are constructed by modifying the wind and mass fields of the control vortex. The EXP-1 vortex is designed to satisfy the necessary condition of baroclinic instability, while the EXP-2 vortex satisfies the necessary condition of barotropic instability. These modified vortices are thought to lie within the natural range of structural variability of hurricanes.The EXP-1 and EXP-2 vortices are found to be unstable with respect to small imposed perturbations, while the control vortex is stable. Small perturbations added to the EXP-1 and EXP-2 vortices grow exponentially at the expense of available potential energy and kinetic energy of the primary vortex, respectively. The most unstable normal modes of both vortices are obtained via a numerical method. The most unstable mode of the EXP-1 (baroclinically unstable) vortex vertically tilts against shear, and the maximum growth occurs near a height of 14 km and a radius of 20 km. On the other hand, the most unstable normal mode of the EXP-2 (barotropically unstable) vortex has horizontal tilting against the mean angular velocity shear

  8. Rock-avalanche and ocean-resurge deposits in the late Eocene Chesapeake Bay impact structure: Evidence from the ICDP-USGS Eyreville cores, Virginia, USA

    USGS Publications Warehouse

    Gohn, G.S.; Powars, D.S.; Dypvik, H.; Edwards, L.E.

    2009-01-01

    An unusually thick section of sedimentary breccias dominated by target-sediment clasts is a distinctive feature of the late Eocene Chesapeake Bay impact structure. A cored 1766-m-deep section recovered from the central part of this marine-target structure by the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) drilling project contains 678 m of these breccias and associated sediments and an intervening 275-m-thick granite slab. Two sedimentary breccia units consist almost entirely of Cretaceous nonmarine sediments derived from the lower part of the target sediment layer. These sediments are present as coherent clasts and as autoclastic matrix between the clasts. Primary (Cretaceous) sedimentary structures are well preserved in some clasts, and liquefaction and fluidization structures produced at the site of deposition occur in the clasts and matrix. These sedimentary breccias are interpreted as one or more rock avalanches from the upper part of the transient-cavity wall. The little-deformed, unshocked granite slab probably was transported as part of an extremely large slide or avalanche. Water-saturated Cretaceous quartz sand below the slab was transported into the seafloor crater prior to, or concurrently with, the granite slab. Two sedimentary breccia units consist of polymict diamictons that contain cobbles, boulders, and blocks of Cretaceous nonmarine target sediments and less common shocked-rock and melt ejecta in an unsorted, unstratified, muddy, fossiliferous, glauconitic quartz matrix. Much of the matrix material was derived from Upper Cretaceous and Paleogene marine target sediments. These units are interpreted as the deposits of debris flows initiated by the resurge of ocean water into the seafloor crater. Interlayering of avalanche and debris-flow units indicates a partial temporal overlap of the earlier avalanche and later resurge processes. A thin unit of stratified turbidite deposits and overlying laminated

  9. Description of Tessaracoccus profundi sp.nov., a deep-subsurface actinobacterium isolated from a Chesapeake impact crater drill core (940 m depth)

    USGS Publications Warehouse

    Finster, K.W.; Cockell, C.S.; Voytek, M.A.; Gronstal, A.L.; Kjeldsen, K.U.

    2009-01-01

    A novel actinobacterium, designated CB31T, was isolated from a 940 m depth sample of a drilling core obtained from the Chesapeake meteor impact crater. The strain was isolated aerobically on R2A medium agar plates supplemented with NaCl (20 g l-1) and MgCl2???6H 2O (3 g l-1). The colonies were circular, convex, smooth and orange. Cells were slightly curved, rod-shaped in young cultures and often appeared in pairs. In older cultures cells were coccoid. Cells stained Gram-positive, were non-motile and did not form endospores. The diagnostic diamino acid of the peptidoglycan was ll-diaminopimelic acid. The polar lipids included phosphatidylglycerol, diphosphatidglycerol, four different glycolipids, two further phospholipids and one unidentified lipid. The dominant menaquinone was MK-9(H4) (70%). The major cellular fatty acid was anteiso C15:0 (83%). The DNA G + C content was 68 mol%. The strain grew anaerobically by reducing nitrate to nitrite or by fermenting glucose. It was catalase positive and oxidase negative. It grew between 10 and 45??C, with an optimum between 35 and 40??C. The pH range for growth was 5.7-9.3, with an optimum at pH 7.5. The closest phylogenetic neighbors based on 16S rRNA gene sequence identity were members of the genus Tessaracoccus (95-96% identity). On the basis of phenotypic and phylogenetic distinctiveness, strain CB31T is considered to represent a novel species of the genus Tessaracoccus, for which we propose the name Tessaracoccus profundi sp. nov.. It is the first member of this genus that has been isolated from a deep subsurface environment. The type strain is CB31T (=NCIMB 14440T = DSM 21240T). ?? 2009 Springer Science+Business Media B.V.

  10. Dephosphorylation of the Core Septin, AspB, in a Protein Phosphatase 2A-Dependent Manner Impacts Its Localization and Function in the Fungal Pathogen Aspergillus fumigatus.

    PubMed

    Vargas-Muñiz, José M; Renshaw, Hilary; Richards, Amber D; Waitt, Greg; Soderblom, Erik J; Moseley, Martin A; Asfaw, Yohannes; Juvvadi, Praveen R; Steinbach, William J

    2016-01-01

    Septins are a conserved family of GTPases that form hetero-oligomeric complexes and perform diverse functions in higher eukaryotes, excluding plants. Our previous studies in the human fungal pathogen Aspergillus fumigatus revealed that the core septin, AspB, a CDC3 ortholog, is required for septation, conidiation, and conidial cell wall organization. Although AspB is important for these cellular functions, nothing is known about the role of kinases or phosphatases in the posttranslational regulation and localization of septins in A. fumigatus. In this study, we assessed the function of the Gin4 and Cla4 kinases and the PP2A regulatory subunit ParA, in the regulation of AspB using genetic and phosphoproteomic approaches. Gene deletion analyses revealed that Cla4 and ParA are indispensable for hyphal extension, and Gin4, Cla4, and ParA are each required for conidiation and normal septation. While deletion of gin4 resulted in larger interseptal distances and hypervirulence, a phenotype mimicking aspB deletion, deletion of cla4 and parA caused hyperseptation without impacting virulence, indicating divergent roles in regulating septation. Phosphoproteomic analyses revealed that AspB is phosphorylated at five residues in the GTPase domain (S134, S137, S247, T297, and T301) and two residues at its C-terminus (S416 and S461) in the wild-type, Δgin4 and Δcla4 strains. However, concomitant with the differential localization pattern of AspB and hyperseptation in the ΔparA strain, AspB remained phosphorylated at two additional residues, T68 in the N-terminal polybasic region and S447 in the coiled-coil domain. Generation of nonphosphorylatable and phosphomimetic strains surrounding each differentially phosphorylated residue revealed that only AspB (mt) -T68E showed increased interseptal distances, suggesting that dephosphorylation of T68 is important for proper septation. This study highlights the importance of septin phosphorylation/dephosphorylation in the regulation of A

  11. Dephosphorylation of the Core Septin, AspB, in a Protein Phosphatase 2A-Dependent Manner Impacts Its Localization and Function in the Fungal Pathogen Aspergillus fumigatus

    PubMed Central

    Vargas-Muñiz, José M.; Renshaw, Hilary; Richards, Amber D.; Waitt, Greg; Soderblom, Erik J.; Moseley, Martin. A.; Asfaw, Yohannes; Juvvadi, Praveen R.; Steinbach, William J.

    2016-01-01

    Septins are a conserved family of GTPases that form hetero–oligomeric complexes and perform diverse functions in higher eukaryotes, excluding plants. Our previous studies in the human fungal pathogen Aspergillus fumigatus revealed that the core septin, AspB, a CDC3 ortholog, is required for septation, conidiation, and conidial cell wall organization. Although AspB is important for these cellular functions, nothing is known about the role of kinases or phosphatases in the posttranslational regulation and localization of septins in A. fumigatus. In this study, we assessed the function of the Gin4 and Cla4 kinases and the PP2A regulatory subunit ParA, in the regulation of AspB using genetic and phosphoproteomic approaches. Gene deletion analyses revealed that Cla4 and ParA are indispensable for hyphal extension, and Gin4, Cla4, and ParA are each required for conidiation and normal septation. While deletion of gin4 resulted in larger interseptal distances and hypervirulence, a phenotype mimicking aspB deletion, deletion of cla4 and parA caused hyperseptation without impacting virulence, indicating divergent roles in regulating septation. Phosphoproteomic analyses revealed that AspB is phosphorylated at five residues in the GTPase domain (S134, S137, S247, T297, and T301) and two residues at its C-terminus (S416 and S461) in the wild-type, Δgin4 and Δcla4 strains. However, concomitant with the differential localization pattern of AspB and hyperseptation in the ΔparA strain, AspB remained phosphorylated at two additional residues, T68 in the N-terminal polybasic region and S447 in the coiled-coil domain. Generation of nonphosphorylatable and phosphomimetic strains surrounding each differentially phosphorylated residue revealed that only AspBmt-T68E showed increased interseptal distances, suggesting that dephosphorylation of T68 is important for proper septation. This study highlights the importance of septin phosphorylation/dephosphorylation in the regulation of A

  12. Core and Lumbopelvic Stabilization in Runners.

    PubMed

    Rivera, Carlos E

    2016-02-01

    Core muscles provide stability that allows generation of force and motion in the lower extremities, as well as distributing impact forces and allowing controlled and efficient body movements. Imbalances or deficiencies in the core muscles can result in increased fatigue, decreased endurance, and injury in runners. Core strengthening should incorporate the intrinsic needs of the core for flexibility, strength, balance, and endurance, and the function of the core in relation to its role in extremity function and dysfunction. Specific exercises are effective in strengthening the core muscles.

  13. Elish-Piper: Response to "Beyond the Common Core: Examining 20 Years of Literacy Priorities and Their Impact on Struggling Readers"

    ERIC Educational Resources Information Center

    Elish-Piper, Laurie

    2016-01-01

    As Cassidy et al. (2016) outline in their article, the Common Core State Standards (CCSS; National Governors Association [NGA] Center for Best Practices & Council of Chief State School Officers [CCSSO], 2010) have taken center stage in education, pushing other important topics and issues aside as teachers scramble to transform their teaching…

  14. The impact of glacier retreat from the Ross Sea on local climate: Characterization of mineral dust in the Taylor Dome ice core, East Antarctica

    NASA Astrophysics Data System (ADS)

    Aarons, S. M.; Aciego, S. M.; Gabrielli, P.; Delmonte, B.; Koornneef, J. M.; Wegner, A.; Blakowski, M. A.

    2016-06-01

    Recent declines in ice shelf and sea ice extent experienced in polar regions highlight the importance of evaluating variations in local weather patterns in response to climate change. Airborne mineral particles (dust) transported through the atmosphere and deposited on ice sheets and glaciers in Antarctica and Greenland can provide a robust set of tools for resolving the evolution of climatic systems through time. Here we present the first high time resolution radiogenic isotope (strontium and neodymium) data for Holocene dust in a coastal East Antarctic ice core, accompanied by rare earth element composition, dust concentration, and particle size distribution during the last deglaciation. We aim to use these combined ice core data to determine dust provenance, with variations indicative of shifts in either dust production, sources, and/or transport pathways. We analyzed a series of 17 samples from the Taylor Dome (77°47‧47″S, 158°43‧26″E) ice core, 113-391 m in depth from 1.1-31.4 ka. Radiogenic isotopic and rare earth element compositions of dust during the last glacial period are in good agreement with previously measured East Antarctic ice core dust records. In contrast, the Holocene dust dataset displays a broad range in isotopic and rare earth element compositions, suggesting a shift from long-range transported dust to a more variable, local input that may be linked to the retreat of the Ross Ice Shelf during the last deglaciation. Observed changes in the dust cycle inferred from a coastal East Antarctic ice core can thus be used to infer an evolving local climate.

  15. Reconstructing the environmental impact of smelters using Pb isotope analyses of peat cores from bogs: Flin Flon, Manitoba and Harjavalta, Finland

    NASA Astrophysics Data System (ADS)

    Shotyk, W.

    2012-04-01

    Located on the Manitoba - Saskatchewan border, the city of Flin Flon has been home to a metallurgical complex since 1930, processing Cu and Zn ores from surrounding mines and consisting of a concentrator, Zn plant, and Cu smelter. Peat cores were collected from two sites, dated using 210Pb, and measured for a broad suite of potentially toxic trace metals. A peat core collected from the bog at Kotyk Lake (30 km NE of FF) shows declines in 206Pb/207Pb from the natural "background" values of 1.25 at the base of the core, to a minimum of 1.02. A peat core collected from the bog at Sask Lake (88 km NW of FF) shows declines in 206Pb/207Pb from the natural "background" values of 1.35 at the base of the core to a minimum of 1.05. But the isotopic evolution of Pb shows significantly declines in 206Pb/207Pb beginning in the late 1800's, presumably because of long-range atmospheric transport from other sources. The 206Pb/207Pb values increase in both cores starting in the 1960's, and reach a recent maximum in the 1990's, apparently reflecting the growing use and eventually phase out of leaded gasoline use. Since the 1990's, the 206Pb/207Pb have continued their decline, apparently reflecting the elimination of leaded gasoline and the growing relative importance of Pb from the smelter. The temporal evolution in Pb enrichment factors follows the history of the metallurgical complex, with the maximum EF values (calculated using Sc) reaching maxima of ca. 100 x (Kotyk Lake) and 10 x (Sask Lake). The maximum rates of atmospheric Pb accumulation are approximately 1200 and 120 μg/m2/yr, respectively. In Finland, peat cores were taken from three bogs: the Pyhäsuo mire in SW Finland, 6 km NE from the Cu Ni smelter at Harjavalta (HAR); at the Viurusuo complex in eastern Finland, 8 km SW of the Cu Ni mine in the town of Outokumpu (OUT); and at Hietajärvi (HJ), in the Patvinsuo National Park of eastern Finland. The cores from HJ and OUT document 3,000 years of anthropogenic Pb and

  16. Impact of Isolated Hepatitis C Virus (HCV) Core-Specific Antibody Detection and Viral RNA Amplification among HCV-Seronegative Dialysis Patients at Risk for Infection

    PubMed Central

    Barril, Guillermina; Quiroga, Juan A.; Arenas, María Dolores; Espinosa, Mario; García-Fernández, Nuria; Cigarrán, Secundino; Herrero, José A.; del Peso, Gloria; Caro, Pilar; García-Agudo, Rebeca; Amézquita, Yésica; Blanco, Ana; Martínez-Rubio, Pilar; Alcázar, José M.; González-Parra, Emilio; Martín-Gómez, Adoración; Castillo, Inmaculada; Bartolomé, Javier

    2014-01-01

    Amplification of hepatitis C virus (HCV) RNA from blood detected occult HCV infections in 30.9% of 210 HCV-seronegative dialysis patients with abnormal liver enzyme levels that had evaded standard HCV testing practices. Isolated HCV core-specific antibody detection identified three additional anti-HCV screening-negative patients lacking HCV RNA amplification in blood who were considered potentially infectious. Together, these findings may affect management of the dialysis setting. PMID:24850345

  17. Gamow-Teller transitions from Mg24 and their impact on the electron capture rates in the O+Ne+Mg cores of stars

    NASA Astrophysics Data System (ADS)

    Nabi, Jameel-Un; Rahman, Muneeb-Ur

    2007-03-01

    Electron captures on nuclei play an important role in the collapse of stellar core in the stages leading to a type-II supernova. Recent observations of subluminous Type II-P supernovae (e.g., 2005cs, 2003gd, 1999br) were able to rekindle the interest in 8 10 M⊙ which develop O+Ne+Mg cores. We used the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory to calculate the B(GT) strength for Mg24 →Na24 and its associated electron capture rates for incorporation in simulation calculations. The calculated rates, in this article, have differences with the earlier reported shell model and Fuller, Fowler, and Newman (hereafter FN2) rates. We compared Gamow-Teller (GT) strength distribution functions and found fairly good agreement with experiment and shell model. However, the GT centroid and the total GT strength, which are useful in the calculation of electron capture rates in the core of massive presupernova stars, lead to the enhancement of our rate up to a factor of 4 compared to the shell model rates at high temperatures and densities.

  18. HOW STARLESS ARE STARLESS CORES?

    SciTech Connect

    Schnee, Scott; Friesen, Rachel; Di Francesco, James; Johnstone, Doug; Enoch, Melissa; Sadavoy, Sarah

    2012-01-20

    In this paper, we present the results of Combined Array for Research in Millimeter-wave Astronomy continuum and spectral line observations of the dense core Per-Bolo 45. Although this core has previously been classified as starless, we find evidence for an outflow and conclude that Per-Bolo 45 is actually an embedded, low-luminosity protostar. We discuss the impact of newly discovered, low-luminosity, embedded objects in the Perseus molecular cloud on starless core and protostar lifetimes. We estimate that the starless core lifetime has been overestimated by 4%-18% and the Class 0/I protostellar lifetime has been underestimated by 5%-20%. Given the relatively large systematic uncertainties involved in these calculations, variations on the order of 10% do not significantly change either core lifetimes or the expected protostellar luminosity function. Finally, we suggest that high-resolution (sub)millimeter surveys of known cores lacking near-infrared and mid-infrared emission are necessary to make an accurate census of starless cores.

  19. The global regulator Ncb2 escapes from the core promoter and impacts transcription in response to drug stress in Candida albicans.

    PubMed

    Shariq, Mohd; Dhamgaye, Sanjiveeni; Nair, Remya; Goyal, Neha; Jain, Vaibhav; Mukhopadhyay, Arnab; Mondal, Alok K; Mukhopadhyay, Gauranga; Prasad, Rajendra

    2017-04-06

    Ncb2, the β subunit of NC2 complex, a heterodimeric regulator of transcription was earlier shown to be involved in the activated transcription of CDR1 gene in azole resistant isolate (AR) of Candida albicans. This study examines its genome-wide role by profiling Ncb2 occupancy between genetically matched pair of azole sensitive (AS) and AR clinical isolates. A comparison of Ncb2 recruitment between the two isolates displayed that 29 genes had higher promoter occupancy of Ncb2 in the AR isolate. Additionally, a host of genes exhibited exclusive occupancy of Ncb2 at promoters of either AR or AS isolate. The analysis also divulged new actors of multi-drug resistance, whose transcription was activated owing to the differential occupancy of Ncb2. The conditional, sequence-specific positional escape of Ncb2 from the core promoter in AS isolate and its preferential recruitment to the core promoter of certain genes in AR isolates was most noteworthy means of transcription regulation. Together, we show that positional rearrangement of Ncb2 resulting in either activation or repression of gene expression in response to drug-induced stress, represents a novel regulatory mechanism that opens new opportunities for therapeutic intervention to prevent development of drug tolerance in C. albicans cells.

  20. The global regulator Ncb2 escapes from the core promoter and impacts transcription in response to drug stress in Candida albicans

    PubMed Central

    Shariq, Mohd; Dhamgaye, Sanjiveeni; Nair, Remya; Goyal, Neha; Jain, Vaibhav; Mukhopadhyay, Arnab; Mondal, Alok K.; Mukhopadhyay, Gauranga; Prasad, Rajendra

    2017-01-01

    Ncb2, the β subunit of NC2 complex, a heterodimeric regulator of transcription was earlier shown to be involved in the activated transcription of CDR1 gene in azole resistant isolate (AR) of Candida albicans. This study examines its genome-wide role by profiling Ncb2 occupancy between genetically matched pair of azole sensitive (AS) and AR clinical isolates. A comparison of Ncb2 recruitment between the two isolates displayed that 29 genes had higher promoter occupancy of Ncb2 in the AR isolate. Additionally, a host of genes exhibited exclusive occupancy of Ncb2 at promoters of either AR or AS isolate. The analysis also divulged new actors of multi-drug resistance, whose transcription was activated owing to the differential occupancy of Ncb2. The conditional, sequence-specific positional escape of Ncb2 from the core promoter in AS isolate and its preferential recruitment to the core promoter of certain genes in AR isolates was most noteworthy means of transcription regulation. Together, we show that positional rearrangement of Ncb2 resulting in either activation or repression of gene expression in response to drug-induced stress, represents a novel regulatory mechanism that opens new opportunities for therapeutic intervention to prevent development of drug tolerance in C. albicans cells. PMID:28383050

  1. Dust Infall Onto Phobos and Deimos Can Explain Their Carbonaceous Reflectance Signature, Perhaps Overlying a Mars-Impact-Origin Core: A Hypothesis

    NASA Technical Reports Server (NTRS)

    Fries, M.; Cintala, M.; Steele, A.; Welzenbach, L. C.

    2017-01-01

    Discussions of Phobos' and Deimos' (henceforth P&D) origin(s) include an unresolved conflict: dynamical studies which favor coalescence of the moons from a large impact on Mars [1,2], versus reflectance spectroscopy of the moons showing a carbonaceous composition that is not consistent with martian surface materials [3-5]. One way to reconcile this discrepancy is to consider the combined options of a Mars impact origin for Phobos and Deimos, followed by deposition of carbon-rich materials by interplanetary dust particle (IDP) infall. This is significant because, unlike asteroidal bodies, P&D experience a high IDP flux due to their location in Mars' gravity well. We present some relatively simple, initial calculations which indicate that accreted carbon may be sufficient to produce a surface with sufficient added carbon to account for P&D's reflectance spectra. If this is true, then a major objection to an impact origin for P&D is resolved.

  2. ENANTIOMERIC RATIOS OF CHIRAL PCB ATROPISOMERS IN RADIODATED SEDIMENT CORES

    EPA Science Inventory

    Enantiomeric ratios (ERs)) of chiral polychlorinated biphenyl (PCB) atropisomers were quantified in radiodated sediment cores of Lake Hartwell SC, a reservoir heavily impacted by PCBS, to study spatial and temporal changes in chirality. A chiral analysis of cores showed accumulat...

  3. Moving core beam energy absorber and converter

    DOEpatents

    Degtiarenko, Pavel V.

    2012-12-18

    A method and apparatus for the prevention of overheating of laser or particle beam impact zones through the use of a moving-in-the-coolant-flow arrangement for the energy absorbing core of the device. Moving of the core spreads the energy deposition in it in 1, 2, or 3 dimensions, thus increasing the effective cooling area of the device.

  4. Quantum-mechanical vs. semi-classical spectral-line widths and shifts from the line core in the non-impact region for the Ar-perturbed/ K-radiator system

    NASA Astrophysics Data System (ADS)

    Kreye, W. C.

    2007-09-01

    New quantum-mechanical (QM) and semi-classical (SC) shifts (d's) and widths (HWHM's, w's) were measured from the line core of computed full spectral-line shapes for the Ar-perturbed/K-radiator system (K/Ar). The initial state of our model was based on a 4p2P3/2,1/2 pseudo-potential for the K/Ar system, and the final state on a zero potential. The Fourier transform of the line shape formed the basis for the computations. Excellent agreement was found between the QM and SC values of d and of w in a high-pressure (P) non-impact region, which was characterized by a √P dependence of w and a P dependence of d. These agreements were shown to be another example of a correspondence between classical (SC) quantities and QM quantities in the limit of large quantum numbers. Typically at P=1×106 Torr and T=400 K, wQM=448 cm-1 and wSC=479 cm-1, where the deviation from the mean is ±3.3%. Also, dQM=-3815 cm-1 and dSC=-3716 cm-1, where the deviation from the mean is ±1.3%. A new general method was formulated which yielded a definite pressure P0, which was defined as an upper limit to the low-pressure impact approximation and a lower limit to the non-impact region.

  5. Oleate Coated Magnetic Cores Based on Magnetite, Zn Ferrite and Co Ferrite Nanoparticles - Preparation, Physical Characterization and Biological Impact on Helianthus Annuus Photosynthesis

    SciTech Connect

    Ursache-Oprisan, Manuela; Foca-nici, Ecaterina; Cirlescu, Aurelian; Caltun, Ovidiu; Creanga, Dorina

    2010-12-02

    Sodium oleate was used as coating shell for magnetite, Zn ferrite and Co ferrite powders to stabilize them in the form of aqueous magnetic suspensions. The physical characterization was carried out by applying X-ray diffraction and magnetization measurements. Both crystallite size and magnetic core diameter ranged between 7 and 11 nm. The influence of magnetic nanoparticle suspensions (corresponding to magnetic nanoparticle levels of 10{sup -14}-10{sup -15}/cm{sup 3}) on sunflower seedlings was studied considering the changes in the photosynthesis pigment levels. Similar responses were obtained for magnetite and cobalt ferrite nanoparticle treatment consisting in the apparent inhibition of chlorophyll biosynthesis while for zinc ferrite nanoparticles some concentrations seemed to have stimulatory effects on the chlorophylls as well as on the carotene levels. But the chlorophyll ratio was diminished in the case of all three types of magnetic nanoparticles meaning their slight negative effect on the light harvesting complex II (LHC II) from the chloroplast membranes and consequently on the photosynthesis efficiency.

  6. Self-Assembled Multivalent (SAMul) Polyanion Binding - Impact of Hydrophobic Modifications in the Micellar Core on DNA and Heparin Binding at the Peripheral Cationic Ligands.

    PubMed

    Albanyan, Buthaina; Laurini, Erik; Posocco, Paola; Pricl, Sabrina; Smith, David K

    2017-03-20

    This paper reports a small family of cationic surfactants designed to bind polyanions such as DNA and heparin. Each molecule has the same hydrophilic cationic ligand, and a hydrophobic aliphatic group with eighteen carbon atoms with either one, two or three alkene groups within the hydrophobic chain (C18-1, C18-2 and C18-3). Dynamic light scattering indicates that more alkenes lead to geometric distortion, giving rise to larger self-assembled multivalent (SAMul) nanostructures. Mallard Blue and Ethidium Bromide dye displacement assays demonstrate that heparin and DNA have markedly different binding preferences, with heparin binding most effectively to C18-1, and DNA to C18-3, even though the molecular structural differences of these SAMul systems are buried in the hydrophobic core. Multiscale modelling suggests that adaptive heparin maximises enthalpically-favourable interactions with C18-1, while shape-persistent DNA forms a similar number of interactions with each ligand display, but with slightly less entropic cost for binding to C18-3 - fundamental thermodynamic differences in SAMul binding of heparin or DNA. This study therefore provides unique insight into electrostatic molecular recognition between highly charged nanoscale surfaces in biologically-relevant systems.

  7. An experimental setup for studying the core-excited atoms and molecules by electron impact using energy analysed electron-ion coincidence technique

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Prajapati, S.; Singh, B.; Singh, B. K.; Shanker, R.

    2017-02-01

    Operation and performance of an apparatus for studying the decay dynamics relevant to core-hole decay processes in atoms and molecules excited by energetic electrons using an energy analysed electron-ion coincidence technique are described in some detail. The setup consists of a time- and position sensitive double-field linear TOF mass spectrometer coupled with a dual MCP detector and a single-pass CMA to select the energy of detected electrons. Details of different components involved in the setup are presented and discussed. To demonstrate the performance and capability of the apparatus, we present some typical results extracted from the TOF argon ion-mass spectra observed in coincidence with 18-energy selected electrons emitted from interaction of a continuous beam of 3.5 keV electrons with a dilute gaseous target of argon atoms. Specifically, the variation of relative correlation probability for the final ion-charge states Ar1+ to Ar4+ produced in the considered collision reactions as a function of energy of emitted electrons is determined and discussed.

  8. Problems with the dating of sediment core using excess (210)Pb in a freshwater system impacted by large scale watershed changes.

    PubMed

    Baskaran, Mark; Nix, Joe; Kuyper, Clark; Karunakara, N

    2014-12-01

    Pb-210 dating of freshwater and coastal sediments have been extensively conducted over the past 40 years for historical pollution reconstruction studies, sediment focusing, sediment accumulation and mixing rate determination. In areas where there is large scale disturbance of sediments and the watershed, the vertical profiles of excess (210)Pb ((210)Pbxs) could provide erroneous or less reliable information on sediment accumulation rates. We analyzed one sediment core from Hendrix Lake in southwestern Arkansas for excess (210)Pb and (137)Cs. There is no decrease in excess (210)Pb activity with depth while the (137)Cs profile indicates sharp peak corresponding to 1963 and the (137)Cs penetration depth of (137)Cs corresponds to 1952. The historical data on the accelerated mercury mining during 1931-1944 resulted in large-scale Hg input to this watershed. Using the peak Hg activity as a time marker, the obtained sediment accumulation rates agree well with the (137)Cs-based rates. Four independent evidences (two-marker events based on (137)Cs and two marker events based on Hg mining activity) result in about the same sedimentation rates and thus, we endorse earlier suggestion that (210)Pb profile always needs to be validated with at least one another independent method. We also present a concise discussion on what important factors that can affect the vertical profiles of (210)Pbxs in relatively smaller lakes.

  9. FIRST INVESTIGATION OF THE COMBINED IMPACT OF IONIZING RADIATION AND MOMENTUM WINDS FROM A MASSIVE STAR ON A SELF-GRAVITATING CORE

    SciTech Connect

    Ngoumou, Judith; Hubber, David; Dale, James E.; Burkert, Andreas

    2015-01-01

    Massive stars shape the surrounding interstellar matter (ISM) by emitting ionizing photons and ejecting material through stellar winds. To study the impact of the momentum from the wind of a massive star on the surrounding neutral or ionized material, we implemented a new HEALPix-based momentum-conserving wind scheme in the smoothed particle hydrodynamics (SPH) code SEREN. A qualitative study of the impact of the feedback from an O7.5-like star on a self-gravitating sphere shows that on its own, the transfer of momentum from a wind onto cold surrounding gas has both a compressing and dispersing effect. It mostly affects gas at low and intermediate densities. When combined with a stellar source's ionizing ultraviolet (UV) radiation, we find the momentum-driven wind to have little direct effect on the gas. We conclude that during a massive star's main sequence, the UV ionizing radiation is the main feedback mechanism shaping and compressing the cold gas. Overall, the wind's effects on the dense gas dynamics and on the triggering of star formation are very modest. The structures formed in the ionization-only simulation and in the combined feedback simulation are remarkably similar. However, in the combined feedback case, different SPH particles end up being compressed. This indicates that the microphysics of gas mixing differ between the two feedback simulations and that the winds can contribute to the localized redistribution and reshuffling of gas.

  10. Metallothionein 2A core promoter region genetic polymorphism and its impact on the risk, tumor behavior, and recurrences of sinonasal inverted papilloma (Schneiderian papilloma).

    PubMed

    Starska, Katarzyna; Bryś, Magdalena; Forma, Ewa; Olszewski, Jurek; Pietkiewicz, Piotr; Lewy-Trenda, Iwona; Stasikowska-Kanicka, Olga; Danilewicz, Marian; Krześlak, Anna

    2015-11-01

    Inverted papillomas are a unique group of locally aggressive benign epithelial neoplasms in the nasal cavity and paranasal sinuses arising from the Schneiderian mucosa. Metallothioneins are sulfhydryl-rich heavy metal-binding proteins required for metal toxicity protection and regulation of biological mechanisms including proliferation and invasion. The goal of this study was to identify three SNPs at loci -5 A/G (rs28366003) and -209 A/G (rs1610216) in the core promoter region and at locus +838 C/G (rs10636) in 3'UTR region of the MT2A gene with IP risk and with tumor invasiveness according to Krouse staging. Genotyping was performed using the PCR restriction fragment length polymorphism technique in 130 genetically unrelated IP individuals, and 418 randomly selected healthy volunteers. The presence of the rs28366003 SNP was significantly related to the risk of IP within the present population-based case-control study. Compared to homozygous common allele carriers, heterozygosity and homozygosity for the G variant had a significantly increased risk of IP (adjusted odds ratio [OR] = 7.71, 95% confidence interval [CI]: 4.01-14.91, p(dominant) < 0.001). Moreover, risk allele carriers demonstrated higher Krouse stage (pT1 vs. pT2-4) (OR = 19.32; 95% CI, 2.30-173.53; p < 0.0001), diffuse tumor growth (OR = 4.58; 95% CI, 1.70-12.11; p = 0.0008), bone destruction (OR = 4.13; 95% CI, 1.50-11.60; p = 0.003), and higher incidence of tumor recurrences (OR = 5.11; 95% CI, 1.68-15.20; p = 0.001). The findings suggest that MT2A gene variation rs28366003 may be implicated in the etiology of sinonasal inverted papilloma in a Polish population.

  11. The Core and Seasonal Microbiota of Raw Bovine Milk in Tanker Trucks and the Impact of Transfer to a Milk Processing Facility

    PubMed Central

    Kable, Mary E.; Srisengfa, Yanin; Laird, Miles; Zaragoza, Jose; McLeod, Jeremy; Heidenreich, Jessie

    2016-01-01

    ABSTRACT Currently, the bacterial composition of raw milk in tanker trucks and the outcomes of transfer and storage of that milk at commercial processing facilities are not well understood. We set out to identify the bacteria in raw milk collected for large-scale dairy product manufacturing. Raw bovine milk samples from 899 tanker trucks arriving at two dairy processors in San Joaquin Valley of California during three seasons (spring, summer, and fall) were analyzed by community 16S rRNA gene sequencing. This analysis revealed highly diverse bacterial populations, which exhibited seasonal differences. Raw milk collected in the spring contained the most diverse bacterial communities, with the highest total cell numbers and highest proportions being those of Actinobacteria. Even with this complexity, a core microbiota was present, consisting of 29 taxonomic groups and high proportions of Streptococcus and Staphylococcus and unidentified members of Clostridiales. Milk samples were also collected from five large-volume silos and from 13 to 25 tankers whose contents were unloaded into each of them during 2 days in the summer. Transfer of the milk to storage silos resulted in two community types. One group of silos contained a high proportion of Streptococcus spp. and was similar in that respect to the tankers that filled them. The community found in the other group of silos was distinct and dominated by Acinetobacter. Overall, despite highly diverse tanker milk community structures, distinct milk bacterial communities were selected within the processing facility environment. This knowledge can inform the development of new sanitation procedures and process controls to ensure the consistent production of safe and high-quality dairy products on a global scale. PMID:27555305

  12. Core-core and core-valence correlation

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

    1988-01-01

    The effect of (1s) core 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 core correlation, is discussed. When both core-core and core-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) core-core correlation is eliminated, and only the core-valence correlation is included, CASSCF/MRCI approached reproduce the FCI results and basis set contraction is significantly easier.

  13. Drought rewires the cores of food webs

    NASA Astrophysics Data System (ADS)

    Lu, Xueke; Gray, Clare; Brown, Lee E.; Ledger, Mark E.; Milner, Alexander M.; Mondragón, Raúl J.; Woodward, Guy; Ma, Athen

    2016-09-01

    Droughts are intensifying across the globe, with potentially devastating implications for freshwater ecosystems. We used new network science approaches to investigate drought impacts on stream food webs and explored potential consequences for web robustness to future perturbations. The substructure of the webs was characterized by a core of richly connected species surrounded by poorly connected peripheral species. Although drought caused the partial collapse of the food webs, the loss of the most extinction-prone peripheral species triggered a substantial rewiring of interactions within the networks’ cores. These shifts in species interactions in the core conserved the underlying core/periphery substructure and stability of the drought-impacted webs. When we subsequently perturbed the webs by simulating species loss in silico, the rewired drought webs were as robust as the larger, undisturbed webs. Our research unearths previously unknown compensatory dynamics arising from within the core that could underpin food web stability in the face of environmental perturbations.

  14. Residential Utility Core Wall System - ResCore

    SciTech Connect

    Boyd, G.; Lundell, C.; Wendt, R.

    1999-06-01

    This paper describes activities associated with the RESidential utility CORE wall system (ResCore) developed by students and faculty in the Department of Industrial Design at Auburn University between 1996 and 1998. These activities analyize three operational prototype units installed in Habitat for Humanity Houses. The paper contains two Parts: 1) analysis of the three operational prototype units, 2) exploration of alternative design solutions. ResCore is a manufactured construction component designed to expedite home building by decreasing the need for skilled labor at the work site. The unit concentrates untility elements into a wall unit(s), which is shipped to the construction site and installed in minimum time. The ResCore unit is intended to be built off-site in a manufacturing environment where the impact of vagaries of weather and work-crew coordination and scheduling are minimized. The controlled environment of the factory enhances efficient production of building components through material and labor throughput controls, enabling the production of components at a substantially reduced per-unit cost. The ResCore unit when compared to traditional "stick-built" utility wall components is in may ways analogous to the factory built roof truss compared to on-site "stick-Built" roof framing.

  15. CO2 Reaction Induced Wettability Alteration and its Impacts on CO2 Storage: Pore to Core Scale Reservoir Condition Experimental Studies

    NASA Astrophysics Data System (ADS)

    Wan, J.; Tokunaga, T. K.; Kim, Y.; Jung, J.; Kim, T.; Dong, W.

    2013-12-01

    Wettability of the mineral surfaces plays an important role in subsurface multiphase flow and transport. Wettability affects the capillary pressure-saturation (Pc- S) relations, relative permeability (kr) of each fluid phase, and relative phase occupancy in reservoir pores. Although wettability issues have been studied extensively in other fields, significant knowledge gaps remain when applying the existing understanding to geological carbon sequestration; due largely to the unique physical-chemical properties of supercritical (sc) CO2 relative to other common non-wetting fluids such as air and oil. Here, we report our recent progress on wettability alteration upon reaction with CO2 and the resulting differences in capillary trapping of CO2 versus air. (1) Pore Scale Studies. There are conflict predictions in the literature concerning the effect of wettability on capillary trapping; some find that larger contact angles lead to lower capillary trapping while others have found opposite behavior. We hypothesized that spontaneous imbibition becomes energetically unfavorable with decreased wettability, so that increased residual trapping of scCO2 should occur during the post-injection inbibition stage. We developed a laboratory high-pressure and elevated temperature microscopic-micromodel system that is capable of controlling fine scale capillary pressure of scCO2-brine, and enabled us to conduct imbibition under controlled capillary pressures at the pore scale. We found that the de-wetting enhanced scCO2 capillary trapping is significant. These results suggest that scCO2 reaction induced dewetting can result in higher degrees of CO2 residual trapping in the post-injection stage than previously predicted. (2) Core Scale Studies. Capillary scaling is used routinely to predict Pc(S) relations for scCO2-brine systems at field scale, based on relations measured with air-water or mercury porosimetry. However, scaling-based predictions for CO2-brine systems have not been

  16. PEG-stabilized core-shell nanoparticles: impact of linear versus dendritic polymer shell architecture on colloidal properties and the reversibility of temperature-induced aggregation.

    PubMed

    Gillich, Torben; Acikgöz, Canet; Isa, Lucio; Schlüter, A Dieter; Spencer, Nicholas D; Textor, Marcus

    2013-01-22

    Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely used experimentally and also clinically tested in diverse areas of biology and medicine. Applications include magnetic resonance imaging, cell sorting, drug delivery, and hyperthermia. Physicochemical surface properties are particularly relevant in the context of achieving high colloidal nanoparticle (NP) stability and preventing agglomeration (particularly challenging in biological fluids), increasing blood circulation time, and possibly targeting specific cells or tissues through the presentation of bioligands. Traditionally, NP surfaces are sterically stabilized with hydrophilic polymeric matrices, such as dextran or linear poly(ethylene glycol) brushes. While dendrimers have found applications as drug carriers, dispersants with dendritic ("dendrons") or hyperbranched structures have been comparatively neglected despite their unique properties, such as a precisely defined molecular structure and the ability to present biofunctionalities at high density at the NP periphery. This work covers the synthesis of SPIONs and their stabilization based on poly(ethylene glycol) (PEG) and oligo(ethylene glycol) (OEG) chemistry and compares the physicochemical properties of NPs stabilized with linear and dendritic macromolecules of comparable molecular weight. The results highlight the impact of the polymeric interface architecture on solubility, colloidal stability, hydrodynamic radius, and thermoresponsive behavior. Dendron-stabilized NPs were found to provide excellent colloidal stability, despite a smaller hydrodynamic radius and lower degree of soft shell hydration compared to linear PEG analogues. Moreover, for the same grafting density and molecular weight of the stabilizers, OEG dendron-stabilized NPs show a reversible temperature-induced aggregation behavior, in contrast to the essentially irreversible aggregation and sedimentation observed for the linear PEG analogues. This new class of

  17. Educators' Perceptions Regarding Common Core State Standards and Professional Development

    ERIC Educational Resources Information Center

    Hipsher, Christine Anne

    2014-01-01

    The purpose of this multiple case study was to explore the impact of the implementation of the Common Core State Standards in Georgia K-12 on the professional development needs of educators. Across the United States the enactment of a Common Core State Standards went into effect. The primary goal of the Common Core State Standards movement was to…

  18. Academic Rigor: The Core of the Core

    ERIC Educational Resources Information Center

    Brunner, Judy

    2013-01-01

    Some educators see the Common Core State Standards as reason for stress, most recognize the positive possibilities associated with them and are willing to make the professional commitment to implementing them so that academic rigor for all students will increase. But business leaders, parents, and the authors of the Common Core are not the only…

  19. Multi-Core Processor Memory Contention Benchmark Analysis Case Study

    NASA Technical Reports Server (NTRS)

    Simon, Tyler; McGalliard, James

    2009-01-01

    Multi-core processors dominate current mainframe, server, and high performance computing (HPC) systems. This paper provides synthetic kernel and natural benchmark results from an HPC system at the NASA Goddard Space Flight Center that illustrate the performance impacts of multi-core (dual- and quad-core) vs. single core processor systems. Analysis of processor design, application source code, and synthetic and natural test results all indicate that multi-core processors can suffer from significant memory subsystem contention compared to similar single-core processors.

  20. Evaluating the travel, physical activity and carbon impacts of a ‘natural experiment’ in the provision of new walking and cycling infrastructure: methods for the core module of the iConnect study

    PubMed Central

    Bull, Fiona; Cooper, Ashley; Rutter, Harry; Adams, Emma; Brand, Christian; Ghali, Karen; Jones, Tim; Mutrie, Nanette; Powell, Jane; Preston, John; Sahlqvist, Shannon; Song, Yena

    2012-01-01

    Introduction Improving infrastructure to support walking and cycling is often regarded as fundamental to encouraging their widespread uptake. However, there is little evidence that specific provision of this kind has led to a significant increase in walking or cycling in practice, let alone wider impacts such as changes in overall physical activity or carbon emissions. Connect2 is a major new project that aims to promote walking and cycling in the UK by improving local pedestrian and cycle routes. It therefore provides a useful opportunity to contribute new evidence in this field by means of a natural experimental study. Methods and analysis iConnect is an independent study that aims to integrate the perspectives of public health and transport research on the measurement and evaluation of the travel, physical activity and carbon impacts of the Connect2 programme. In this paper, the authors report the study design and methods for the iConnect core module. This comprised a cohort study of residents living within 5 km of three case study Connect2 projects in Cardiff, Kenilworth and Southampton, supported by a programme of qualitative interviews with key informants about the projects. Participants were asked to complete postal questionnaires, repeated before and after the opening of the new infrastructure, which collected data on demographic and socioeconomic characteristics, travel, car fuel purchasing and physical activity, and potential psychosocial and environmental correlates and mediators of those behaviours. In the absence of suitable no-intervention control groups, the study design drew on heterogeneity in exposure both within and between case study samples to provide for a counterfactual. Ethics and dissemination The study was approved by the University of Southampton Research Ethics Committee. The findings will be disseminated through academic presentations, peer-reviewed publications and the study website (http://www.iconnect.ac.uk) and by means of a

  1. Coring Sample Acquisition Tool

    NASA Technical Reports Server (NTRS)

    Haddad, Nicolas E.; Murray, Saben D.; Walkemeyer, Phillip E.; Badescu, Mircea; Sherrit, Stewart; Bao, Xiaoqi; Kriechbaum, Kristopher L.; Richardson, Megan; Klein, Kerry J.

    2012-01-01

    A sample acquisition tool (SAT) has been developed that can be used autonomously to sample drill and capture rock cores. The tool is designed to accommodate core transfer using a sample tube to the IMSAH (integrated Mars sample acquisition and handling) SHEC (sample handling, encapsulation, and containerization) without ever touching the pristine core sample in the transfer process.

  2. Silicon in the Earth's core.

    PubMed

    Georg, R Bastian; Halliday, Alex N; Schauble, Edwin A; Reynolds, Ben C

    2007-06-28

    Small isotopic differences between the silicate minerals in planets may have developed as a result of processes associated with core formation, or from evaporative losses during accretion as the planets were built up. Basalts from the Earth and the Moon do indeed appear to have iron isotopic compositions that are slightly heavy relative to those from Mars, Vesta and primitive undifferentiated meteorites (chondrites). Explanations for these differences have included evaporation during the 'giant impact' that created the Moon (when a Mars-sized body collided with the young Earth). However, lithium and magnesium, lighter elements with comparable volatility, reveal no such differences, rendering evaporation unlikely as an explanation. Here we show that the silicon isotopic compositions of basaltic rocks from the Earth and the Moon are also distinctly heavy. A likely cause is that silicon is one of the light elements in the Earth's core. We show that both the direction and magnitude of the silicon isotopic effect are in accord with current theory based on the stiffness of bonding in metal and silicate. The similar isotopic composition of the bulk silicate Earth and the Moon is consistent with the recent proposal that there was large-scale isotopic equilibration during the giant impact. We conclude that Si was already incorporated as a light element in the Earth's core before the Moon formed.

  3. BN-600 full MOX core benchmark analysis.

    SciTech Connect

    Kim, Y. I.; Hill, R. N.; Grimm, K.; Rimpault, G.; Newton, T.; Li, Z. H.; Rineiski, A.; Mohanakrishan, P.; Ishikawa, M.; Lee, K. B.; Danilytchev, A.; Stogov, V.; Nuclear Engineering Division; International Atomic Energy Agency; CEA SERCO Assurance; China Inst. of Atomic Energy; Forschnungszentrum Karlsruhe; Indira Gandhi Centre for Atomic Research; Japan Nuclear Cycle Development Inst.; Korea Atomic Energy Research Inst.; Inst. of Physics and Power Engineering

    2004-01-01

    As a follow-up of the BN-600 hybrid core benchmark, a full MOX core benchmark was performed within the framework of the IAEA co-ordinated research project. Discrepancies between the values of main reactivity coefficients obtained by the participants for the BN-600 full MOX core benchmark appear to be larger than those in the previous hybrid core benchmarks on traditional core configurations. This arises due to uncertainties in the proper modelling of the axial sodium plenum above the core. It was recognized that the sodium density coefficient strongly depends on the core model configuration of interest (hybrid core vs. fully MOX fuelled core with sodium plenum above the core) in conjunction with the calculation method (diffusion vs. transport theory). The effects of the discrepancies revealed between the participants results on the ULOF and UTOP transient behaviours of the BN-600 full MOX core were investigated in simplified transient analyses. Generally the diffusion approximation predicts more benign consequences for the ULOF accident but more hazardous ones for the UTOP accident when compared with the transport theory results. The heterogeneity effect does not have any significant effect on the simulation of the transient. The comparison of the transient analyses results concluded that the fuel Doppler coefficient and the sodium density coefficient are the two most important coefficients in understanding the ULOF transient behaviour. In particular, the uncertainty in evaluating the sodium density coefficient distribution has the largest impact on the description of reactor dynamics. This is because the maximum sodium temperature rise takes place at the top of the core and in the sodium plenum.

  4. Banded transformer cores

    NASA Technical Reports Server (NTRS)

    Mclyman, C. W. T. (Inventor)

    1974-01-01

    A banded transformer core formed by positioning a pair of mated, similar core halves on a supporting pedestal. The core halves are encircled with a strap, selectively applying tension whereby a compressive force is applied to the core edge for reducing the innate air gap. A dc magnetic field is employed in supporting the core halves during initial phases of the banding operation, while an ac magnetic field subsequently is employed for detecting dimension changes occurring in the air gaps as tension is applied to the strap.

  5. Postimpact heat conduction and compaction-driven fluid flow in the Chesapeake Bay impact structure based on downhole vitrinite reflectance data, ICDP-USGS Eyreville deep core holes and Cape Charles test holes

    USGS Publications Warehouse

    Malinconico, M.L.; Sanford, W.E.; Wright, Horton W.J.J.

    2009-01-01

    Vitrinite reflectance data from the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville deep cores in the centralcrater moat of the Chesapeake Bay impact structure and the Cape Charles test holes on the central uplift show patterns of postimpact maximum-temperature distribution that result from a combination of conductive and advective heat flow. Within the crater-fill sediment-clast breccia sequence at Eyreville, an isoreflectance (-0.44% Ro) section (525-1096 m depth) is higher than modeled background coastal-plain maturity and shows a pattern typical of advective fluid flow. Below an intervening granite slab, a short interval of sediment-clast breccia (1371-1397 m) shows a sharp increase in reflectance (0.47%-0.91% Ro) caused by conductive heat from the underlying suevite (1397-1474 m). Refl ectance data in the uppermost suevite range from 1.2% to 2.1% Ro. However, heat conduction alone is not sufficient to affect the temperature of sediments more than 100 m above the suevite. Thermal modeling of the Eyreville suevite as a 390 ??C cooling sill-like hot rock layer supplemented by compaction- driven vertical fluid flow (0.046 m/a) of cooling suevitic fluids and deeper basement brines (120 ??C) upward through the sediment breccias closely reproduces the measured reflectance data. This scenario would also replace any marine water trapped in the crater fill with more saline brine, similar to that currently in the crater, and it would produce temperatures sufficient to kill microbes in sediment breccias within 450 m above the synimsuevite. A similar downhole maturity pattern is present in the sediment-clast breccia over the central uplift. High-reflectance (5%-9%) black shale and siltstone clasts in the suevite and sediment-clast breccia record a pre-impact (Paleozoic?) metamorphic event. Previously published maturity data in the annular trough indicate no thermal effect there from impact-related processes. ?? 2009 The

  6. HYDRATE CORE DRILLING TESTS

    SciTech Connect

    John H. Cohen; Thomas E. Williams; Ali G. Kadaster; Bill V. Liddell

    2002-11-01

    The ''Methane Hydrate Production from Alaskan Permafrost'' project is a three-year endeavor being conducted by Maurer Technology Inc. (MTI), Noble, and Anadarko Petroleum, in partnership with the U.S. DOE National Energy Technology Laboratory (NETL). The project's goal is to build on previous and ongoing R&D in the area of onshore hydrate deposition. The project team plans to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope includes drilling and coring one well on Anadarko leases in FY 2003 during the winter drilling season. A specially built on-site core analysis laboratory will be used to determine some of the physical characteristics of the hydrates and surrounding rock. Prior to going to the field, the project team designed and conducted a controlled series of coring tests for simulating coring of hydrate formations. A variety of equipment and procedures were tested and modified to develop a practical solution for this special application. This Topical Report summarizes these coring tests. A special facility was designed and installed at MTI's Drilling Research Center (DRC) in Houston and used to conduct coring tests. Equipment and procedures were tested by cutting cores from frozen mixtures of sand and water supported by casing and designed to simulate hydrate formations. Tests were conducted with chilled drilling fluids. Tests showed that frozen core can be washed out and reduced in size by the action of the drilling fluid. Washing of the core by the drilling fluid caused a reduction in core diameter, making core recovery very difficult (if not impossible). One successful solution was to drill the last 6 inches of core dry (without fluid circulation). These tests demonstrated that it will be difficult to capture core when drilling in permafrost or hydrates without implementing certain safeguards. Among the coring tests was a simulated hydrate formation comprised of coarse, large

  7. 23. CORE WORKER OPERATING A COREBLOWER THAT PNEUMATICALLY FILLED CORE ...

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

    23. CORE WORKER OPERATING A CORE-BLOWER THAT PNEUMATICALLY FILLED CORE BOXES WITH RESIGN IMPREGNATED SAND AND CREATED A CORE THAT THEN REQUIRED BAKING, CA. 1950. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  8. Core-Cutoff Tool

    NASA Technical Reports Server (NTRS)

    Gheen, Darrell

    2007-01-01

    A tool makes a cut perpendicular to the cylindrical axis of a core hole at a predetermined depth to free the core at that depth. The tool does not damage the surrounding material from which the core was cut, and it operates within the core-hole kerf. Coring usually begins with use of a hole saw or a hollow cylindrical abrasive cutting tool to make an annular hole that leaves the core (sometimes called the plug ) in place. In this approach to coring as practiced heretofore, the core is removed forcibly in a manner chosen to shear the core, preferably at or near the greatest depth of the core hole. Unfortunately, such forcible removal often damages both the core and the surrounding material (see Figure 1). In an alternative prior approach, especially applicable to toxic or fragile material, a core 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 core hole. The sleeves are thin enough that this tool fits within the kerf of the core 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 core. 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 core pulls the cutting wire into contact with the core. The cutting force of the wire against the core increases with the tension in the wire and

  9. Core sample extractor

    NASA Technical Reports Server (NTRS)

    Akins, James; Cobb, Billy; Hart, Steve; Leaptrotte, Jeff; Milhollin, James; Pernik, Mark

    1989-01-01

    The problem of retrieving and storing core samples from a hole drilled on the lunar surface is addressed. The total depth of the hole in question is 50 meters with a maximum diameter of 100 millimeters. The core sample itself has a diameter of 60 millimeters and will be two meters in length. It is therefore necessary to retrieve and store 25 core samples per hole. The design utilizes a control system that will stop the mechanism at a certain depth, a cam-linkage system that will fracture the core, and a storage system that will save and catalogue the cores to be extracted. The Rod Changer and Storage Design Group will provide the necessary tooling to get into the hole as well as to the core. The mechanical design for the cam-linkage system as well as the conceptual design of the storage device are described.

  10. Petrographic and geochemical comparisons between the lower crystalline basement-derived section and the granite megablock and amphibolite megablock of the Eyreville B core, Chesapeake Bay impact structure, USA

    USGS Publications Warehouse

    Townsend, G.N.; Gibson, R.L.; Horton, J.W.; Reimold, W.U.; Schmitt, R.T.; Bartosova, K.

    2009-01-01

    The Eyreville B core from the Chesapeake Bay impact structure, Virginia, USA, contains a lower basement-derived section (1551.19 m to 1766.32 m deep) and two megablocks of dominantly (1) amphibolite (1376.38 m to 1389.35 m deep) and (2) granite (1095.74 m to 1371.11 m deep), which are separated by an impactite succession. Metasedimentary rocks (muscovite-quartz-plagioclase-biotite-graphite ?? fibrolite ?? garnet ?? tourmaline ?? pyrite ?? rutile ?? pyrrhotite mica schist, hornblende-plagioclase-epidote-biotite- K-feldspar-quartz-titanite-calcite amphibolite, and vesuvianite-plagioclase- quartz-epidote calc-silicate rock) are dominant in the upper part of the lower basement-derived section, and they are intruded by pegmatitic to coarse-grained granite (K-feldspar-plagioclase-quartz-muscovite ?? biotite ?? garnet) that increases in volume proportion downward. The granite megablock contains both gneissic and weakly or nonfoliated biotite granite varieties (K-feldspar-quartz-plagioclase-biotite ?? muscovite ?? pyrite), with small schist xenoliths consisting of biotite-plagioclase-quartz ?? epidote ?? amphibole. The lower basement-derived section and both megablocks exhibit similar middleto upper-amphibolite-facies metamorphic grades that suggest they might represent parts of a single terrane. However, the mica schists in the lower basement-derived sequence and in the megablock xenoliths show differences in both mineralogy and whole-rock chemistry that suggest a more mafi c source for the xenoliths. Similarly, the mineralogy of the amphibolite in the lower basement-derived section and its association with calc-silicate rock suggest a sedimentary protolith, whereas the bulk-rock and mineral chemistry of the megablock amphibolite indicate an igneous protolith. The lower basement-derived granite also shows bulk chemical and mineralogical differences from the megablock gneissic and biotite granites. ?? 2009 The Geological Society of America.

  11. Petrographic and geochemical comparisons between the lower crystalline basement-derived section and the granite megablock and amphibolite megablock of the Eyreville-B core, Chesapeake Bay impact structure

    USGS Publications Warehouse

    Townsend, Gabrielle N.; Gibson, Roger L.; Horton, J. Wright; Reimold, Wolf Uwe; Schmitt, Ralf T.; Bartosova, Katerina

    2009-01-01

    The Eyreville B core from the Chesapeake Bay impact structure, Virginia, USA, contains a lower basement-derived section (1551.19 m to 1766.32 m deep) and two megablocks of dominantly (1) amphibolite (1376.38 m to 1389.35 m deep) and (2) granite (1095.74 m to 1371.11 m deep), which are separated by an impactite succession. Metasedimentary rocks (muscovite-quartz-plagioclase-biotite-graphite ± fibrolite ± garnet ± tourmaline ± pyrite ± rutile ± pyrrhotite mica schist, hornblende-plagioclase-epidote-biotite-K-feldspar-quartz-titanite-calcite amphibolite, and vesuvianite-plagioclase-quartz-epidote calc-silicate rock) are dominant in the upper part of the lower basement-derived section, and they are intruded by pegmatitic to coarse-grained granite (K-feldspar-plagioclase-quartz-muscovite ± biotite ± garnet) that increases in volume proportion downward. The granite megablock contains both gneissic and weakly or nonfoliated biotite granite varieties (K-feldspar-quartz-plagioclase-biotite ± muscovite ± pyrite), with small schist xenoliths consisting of biotite-plagioclase-quartz ± epidote ± amphibole. The lower basement-derived section and both megablocks exhibit similar middle- to upper-amphibolite-facies metamorphic grades that suggest they might represent parts of a single terrane. However, the mica schists in the lower basement-derived sequence and in the megablock xenoliths show differences in both mineralogy and whole-rock chemistry that suggest a more mafic source for the xenoliths. Similarly, the mineralogy of the amphibolite in the lower basement-derived section and its association with calc-silicate rock suggest a sedimentary protolith, whereas the bulk-rock and mineral chemistry of the megablock amphibolite indicate an igneous protolith. The lower basement-derived granite also shows bulk chemical and mineralogical differences from the megablock gneissic and biotite granites.

  12. The core paradox.

    NASA Technical Reports Server (NTRS)

    Kennedy, G. C.; Higgins, G. H.

    1973-01-01

    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 core was thermally stably stratified and that this stratification might prove a powerful inhibitor to circulation of the outer core fluid of the kind postulated for the generation of the earth's magnetic field. These suggestions are examined and shown to provide no reasonable escape from the core paradox.

  13. Core Research Center

    USGS Publications Warehouse

    Hicks, Joshua; Adrian, Betty

    2009-01-01

    The Core Research Center (CRC) of the U.S. Geological Survey (USGS), located at the Denver Federal Center in Lakewood, Colo., currently houses rock core from more than 8,500 boreholes representing about 1.7 million feet of rock core from 35 States and cuttings from 54,000 boreholes representing 238 million feet of drilling in 28 States. Although most of the boreholes are located in the Rocky Mountain region, the geologic and geographic diversity of samples have helped the CRC become one of the largest and most heavily used public core repositories in the United States. Many of the boreholes represented in the collection were drilled for energy and mineral exploration, and many of the cores and cuttings were donated to the CRC by private companies in these industries. Some cores and cuttings were collected by the USGS along with other government agencies. Approximately one-half of the cores are slabbed and photographed. More than 18,000 thin sections and a large volume of analytical data from the cores and cuttings are also accessible. A growing collection of digital images of the cores are also becoming available on the CRC Web site Internet http://geology.cr.usgs.gov/crc/.

  14. Can Psychiatric Rehabilitation Be Core to CORE?

    ERIC Educational Resources Information Center

    Olney, Marjorie F.; Gill, Kenneth J.

    2016-01-01

    Purpose: In this article, we seek to determine whether psychiatric rehabilitation principles and practices have been more fully incorporated into the Council on Rehabilitation Education (CORE) standards, the extent to which they are covered in four rehabilitation counseling "foundations" textbooks, and how they are reflected in the…

  15. Making an Ice Core.

    ERIC Educational Resources Information Center

    Kopaska-Merkel, David C.

    1995-01-01

    Explains an activity in which students construct a simulated ice core. Materials required include only a freezer, food coloring, a bottle, and water. This hands-on exercise demonstrates how a glacier is formed, how ice cores are studied, and the nature of precision and accuracy in measurement. Suitable for grades three through eight. (Author/PVD)

  16. Core Concepts of Kinesiology.

    ERIC Educational Resources Information Center

    Hudson, Jackie L.

    1995-01-01

    Core concepts of kinesiology are the basis of communication about movement that facilitate progression of skill levels. The article defines and exemplifies each of 10 core concepts: range of motion, speed of motion, number of segments, nature of segments, balance, coordination, compactness, extension at release/contact, path of projection, and…

  17. CORE - Performance Feedback System

    SciTech Connect

    2009-10-02

    CORE is an architecture to bridge the gaps between disparate data integration and delivery of disparate information visualization. The CORE Technology Program includes a suite of tools and user-centered staff that can facilitate rapid delivery of a deployable integrated information to users.

  18. Iowa Core Annual Report

    ERIC Educational Resources Information Center

    Iowa Department of Education, 2015

    2015-01-01

    One central component of a great school system is a clear set of expectations, or standards, that educators help all students reach. In Iowa, that effort is known as the Iowa Core. The Iowa Core represents the statewide academic standards, which describe what students should know and be able to do in math, science, English language arts, and…

  19. Ice Core Investigations

    ERIC Educational Resources Information Center

    Krim, Jessica; Brody, Michael

    2008-01-01

    What can glaciers tell us about volcanoes and atmospheric conditions? How does this information relate to our understanding of climate change? Ice Core Investigations is an original and innovative activity that explores these types of questions. It brings together popular science issues such as research, climate change, ice core drilling, and air…

  20. Modular core holder

    SciTech Connect

    Mueller, J.; Cole, C.W.; Hamid, S.; Lucas, J.K.

    1991-03-05

    This patent describes a modular core holder. It comprises: a sleeve, forming an internal cavity for receiving a core. The sleeve including segments; support means, overlying the sleeve, for supporting the sleeve; and access means, positioned between at least two of the segments of the sleeve, for allowing measurement of conditions within the internal cavity.

  1. More on the Core

    ERIC Educational Resources Information Center

    Chan, Monnica

    2013-01-01

    From a higher education perspective, new "Common Core" standards could improve student college-readiness levels, reduce institutional remediation rates, and close education gaps in and between states. As a national initiative to create common educational standards for students across multiple states, the Common Core State Standards…

  2. Mercury's core evolution

    NASA Astrophysics Data System (ADS)

    Deproost, Marie-Hélène; Rivoldini, Attilio; Van Hoolst, Tim

    2016-10-01

    Remote sensing data of Mercury's surface by MESSENGER indicate that Mercury formed under reducing conditions. As a consequence, silicon is likely the main light element in the core together with a possible small fraction of sulfur. Compared to sulfur, which does almost not partition into solid iron at Mercury's core conditions and strongly decreases the melting temperature, silicon partitions almost equally well between solid and liquid iron and is not very effective at reducing the melting temperature of iron. Silicon as the major light element constituent instead of sulfur therefore implies a significantly higher core liquidus temperature and a decrease in the vigor of compositional convection generated by the release of light elements upon inner core formation.Due to the immiscibility in liquid Fe-Si-S at low pressure (below 15 GPa), the core might also not be homogeneous and consist of an inner S-poor Fe-Si core below a thinner Si-poor Fe-S layer. Here, we study the consequences of a silicon-rich core and the effect of the blanketing Fe-S layer on the thermal evolution of Mercury's core and on the generation of a magnetic field.

  3. NFE Core Bibliographies.

    ERIC Educational Resources Information Center

    Michigan State Univ., East Lansing. Inst. for International Studies in Education.

    This collection of core bibliographies, which expands on an initial bibliography published in 1979 of the core resources housed in the Non-Formal Education Information Center at Michigan State University, comprises a basic stock of materials on nonformal education and women in development that have been contributed by development planners,…

  4. Internal core tightener

    DOEpatents

    Brynsvold, Glen V.; Snyder, Jr., Harold J.

    1976-06-22

    An internal core tightener which is a linear actuated (vertical actuation motion) expanding device utilizing a minimum of moving parts to perform the lateral tightening function. The key features are: (1) large contact areas to transmit loads during reactor operation; (2) actuation cam surfaces loaded only during clamping and unclamping operation; (3) separation of the parts and internal operation involved in the holding function from those involved in the actuation function; and (4) preloaded pads with compliant travel at each face of the hexagonal assembly at the two clamping planes to accommodate thermal expansion and irradiation induced swelling. The latter feature enables use of a "fixed" outer core boundary, and thus eliminates the uncertainty in gross core dimensions, and potential for rapid core reactivity changes as a result of core dimensional change.

  5. Lunar Core and Tides

    NASA Technical Reports Server (NTRS)

    Williams, J. G.; Boggs, D. H.; Ratcliff, J. T.

    2004-01-01

    Variations in rotation and orientation of the Moon are sensitive to solid-body tidal dissipation, dissipation due to relative motion at the fluid-core/solid-mantle boundary, and tidal Love number k2 [1,2]. There is weaker sensitivity to flattening of the core-mantle boundary (CMB) [2,3,4] and fluid core moment of inertia [1]. Accurate Lunar Laser Ranging (LLR) measurements of the distance from observatories on the Earth to four retroreflector arrays on the Moon are sensitive to lunar rotation and orientation variations and tidal displacements. Past solutions using the LLR data have given results for dissipation due to solid-body tides and fluid core [1] plus Love number [1-5]. Detection of CMB flattening, which in the past has been marginal but improving [3,4,5], now seems significant. Direct detection of the core moment has not yet been achieved.

  6. Geothermal temperature gradient core drill, Santiam Pass

    SciTech Connect

    Not Available

    1989-01-01

    DOE is proposing to share in the cost of drilling a 3000-ft core hole to evaluate temperature gradients, subsurface geology and the geothermal potential of an area in the Cascade Mountains. The proposed core hole will be located in the Deschutes National Forest in Oregon, near Santiam Pass. The proposed action has been described in the Environmental Assessment (EA) for Geothermal Temperature Gradient Core Drill Santiam Pass Area (No. OR-050-9-51) prepared by the US Bureau of Land Management (BLM). DOE has determined that the BLM EA adequately addresses the impacts of the proposal and is hereby adopting the EA in partial fulfillment of its NEPA responsibilities. Based upon a review of the EA and an independent analysis, DOE has concluded that the proposed corehole drilling project does not constitute a major federal action significantly affecting the quality of the human environment within the meaning of NEPA. Therefore, an environmental impact statement will not be prepared.

  7. A CORE approach to progress monitoring and feedback: Enhancing evidence and improving practice.

    PubMed

    Barkham, Michael; Mellor-Clark, John; Stiles, William B

    2015-12-01

    This article describes the Clinical Outcomes in Routine Evaluation (CORE) System and reports on its scientific yield and practice impact. First, we describe the suite of CORE measures, including the centerpiece CORE-Outcome Measure (CORE-OM), its short forms, special purpose forms, translations, and psychometric properties, along with the pretreatment CORE Therapy Assessment Form and the CORE End of Therapy Form. Second, we provide an overview of the scientific yield arising from analyses of large CORE data sets collected in routine practice. Third, we describe the use of CORE measures for feedback in practice settings. Finally, we consider future directions for monitoring and feedback in research and practice.

  8. Common Core State Standards and Adaptive Teaching

    ERIC Educational Resources Information Center

    Kamil, Michael L.

    2016-01-01

    This article examines the issues of how Common Core State Standards (CCSS) will impact adaptive teaching. It focuses on 2 of the major differences between conventional standards and CCSS: the increased complexity of text and the addition of disciplinary literacy standards to reading instruction. The article argues that adaptive teaching under CCSS…

  9. At the Center of the Common Core

    ERIC Educational Resources Information Center

    Principal, 2012

    2012-01-01

    While the 2011-2012 school year offered educators a sketch of the Common Core State Standards and how they would impact teaching and learning, this year that painting takes shape. Many states and districts are well on the way to implementing the standards--but the process is complex, especially for the school leaders who shoulder the task of…

  10. NEPHTIS: Core depletion validation relying on 2D transport core calculations with the APOLLO2 code

    SciTech Connect

    Damian, F.; Raepsaet, X.; Groizard, M.; Poinot, C.

    2006-07-01

    The CEA, in collaboration with EDF and AREVA-NP, is developing a core modelling tool called NEPHTIS, for Neutronic Process for HTGR Innovating Systems and dedicated at present day to the prismatic block-type HTGR (High Temperature Gas-Cooled Reactors). Due to the lack of usable HTGR experimental results, the confidence in this neutronic computational tool relies essentially on comparisons to reference or best-estimate calculations. In the present analysis, the Aleppo deterministic transport code has been selected as reference for validating core depletion simulations carried out within NEPHTIS. These reference calculations were performed on fully detailed 2D core configurations using the Method of Characteristics. The latter has been validated versus Monte Carlo method for different static core configurations [1], [2] and [3]. All the presented results come from an annular HTGR core loaded with uranium-based fuel (15% enrichment). During the core depletion validation, reactivity, reaction rates distributions and nuclei concentrations have been compared. In addition, the impact of various physical and geometrical parameters such as the core loading (one-through or batch-wise reloading) and the amount of burnable poison has been investigated during the validation phases. The results confirm that NEPHTIS is able to predict the core reactivity with uncertainties of {+-}350 pcm. At the end of the core irradiation, the U-235 consumption is calculated within {+-} 0, 7 % while the plutonium mass discharged from the core is calculated within {+-}1 %. As far as the core power distributions are concerned, small discrepancies ( and < 2.3 %) can be observed on the fuel block-averaged power distribution in the core. (authors)

  11. 34. DESPATCH CORE OVENS, GREY IRON FOUNDRY CORE ROOM, BAKES ...

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

    34. DESPATCH CORE OVENS, GREY IRON FOUNDRY CORE ROOM, BAKES CORES THAT ARE NOT MADE ON HEATED OR COLD BOX CORE MACHINES, TO SET BINDING AGENTS MIXED WITH THE SAND CREATING CORES HARD ENOUGH TO WITHSTAND THE FLOW OF MOLTEN IRON INSIDE A MOLD. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  12. Multiple Core Galaxies

    NASA Technical Reports Server (NTRS)

    Miller, R.H.; Morrison, David (Technical Monitor)

    1994-01-01

    Nuclei of galaxies often show complicated density structures and perplexing kinematic signatures. In the past we have reported numerical experiments indicating a natural tendency for galaxies to show nuclei offset with respect to nearby isophotes and for the nucleus to have a radial velocity different from the galaxy's systemic velocity. Other experiments show normal mode oscillations in galaxies with large amplitudes. These oscillations do not damp appreciably over a Hubble time. The common thread running through all these is that galaxies often show evidence of ringing, bouncing, or sloshing around in unexpected ways, even though they have not been disturbed by any external event. Recent observational evidence shows yet another phenomenon indicating the dynamical complexity of central regions of galaxies: multiple cores (M31, Markarian 315 and 463 for example). These systems can hardly be static. We noted long-lived multiple core systems in galaxies in numerical experiments some years ago, and we have more recently followed up with a series of experiments on multiple core galaxies, starting with two cores. The relevant parameters are the energy in the orbiting clumps, their relative.masses, the (local) strength of the potential well representing the parent galaxy, and the number of cores. We have studied the dependence of the merger rates and the nature of the final merger product on these parameters. Individual cores survive much longer in stronger background potentials. Cores can survive for a substantial fraction of a Hubble time if they travel on reasonable orbits.

  13. Global Core Plasma Model

    NASA Technical Reports Server (NTRS)

    Gallagher, Dennis L.; Craven, P. D.; Comfort, R. H.

    1999-01-01

    Abstract. The Global Core Plasma Model (GCPM) provides, empirically derived, core plasma density as a function of geomagnetic and solar conditions throughout the inner magnetosphere. It is continuous in value and gradient and is composed of separate models for the ionosphere, the plasmasphere, the plasmapause, the trough, and the polar cap. The relative composition of plasmaspheric H+, He+, and O+ is included in the GCPM. A blunt plasmaspheric bulge and rotation of the bulge with changing geomagnetic conditions is included. The GCPM is an amalgam of density models, intended to serve as a framework for continued improvement as new measurements become available and are used to characterize core plasma density, composition, and temperature.

  14. Core shroud corner joints

    DOEpatents

    Gilmore, Charles B.; Forsyth, David R.

    2013-09-10

    A core shroud is provided, which includes a number of planar members, a number of unitary corners, and a number of subassemblies each comprising a combination of the planar members and the unitary corners. Each unitary corner comprises a unitary extrusion including a first planar portion and a second planar portion disposed perpendicularly with respect to the first planar portion. At least one of the subassemblies comprises a plurality of the unitary corners disposed side-by-side in an alternating opposing relationship. A plurality of the subassemblies can be combined to form a quarter perimeter segment of the core shroud. Four quarter perimeter segments join together to form the core shroud.

  15. Self-mixing phenomenology in hypothetical core-disruptive accidents

    SciTech Connect

    Chapyak, E.J.

    1980-12-01

    Physical processes are investigated that lead to the thermal equilibration of a disrupted liquid metal fast breeder reactor (LMFBR) core following a hypothetical core-disruptive accident (HCDA). Their impact is assessed, particularly as relating to the SIMMER code. The turbulent structure in the core region is characterized and bounding estimates are derived of thermal equilibration (''self-mixing'') times. The implication of these results for LMFBR safety research is discussed briefly.

  16. Oak Ridge National Laboratory Core Competencies

    SciTech Connect

    Roberto, J.B.; Anderson, T.D.; Berven, B.A.; Hildebrand, S.G.; Hartman, F.C.; Honea, R.B.; Jones, J.E. Jr.; Moon, R.M. Jr.; Saltmarsh, M.J.; Shelton, R.B.

    1994-12-01

    A core competency is a distinguishing integration of capabilities which enables an organization to deliver mission results. Core competencies represent the collective learning of an organization and provide the capacity to perform present and future missions. Core competencies are distinguishing characteristics which offer comparative advantage and are difficult to reproduce. They exhibit customer focus, mission relevance, and vertical integration from research through applications. They are demonstrable by metrics such as level of investment, uniqueness of facilities and expertise, and national impact. The Oak Ridge National Laboratory (ORNL) has identified four core competencies which satisfy the above criteria. Each core competency represents an annual investment of at least $100M and is characterized by an integration of Laboratory technical foundations in physical, chemical, and materials sciences; biological, environmental, and social sciences; engineering sciences; and computational sciences and informatics. The ability to integrate broad technical foundations to develop and sustain core competencies in support of national R&D goals is a distinguishing strength of the national laboratories. The ORNL core competencies are: 9 Energy Production and End-Use Technologies o Biological and Environmental Sciences and Technology o Advanced Materials Synthesis, Processing, and Characterization & Neutron-Based Science and Technology. The distinguishing characteristics of each ORNL core competency are described. In addition, written material is provided for two emerging competencies: Manufacturing Technologies and Computational Science and Advanced Computing. Distinguishing institutional competencies in the Development and Operation of National Research Facilities, R&D Integration and Partnerships, Technology Transfer, and Science Education are also described. Finally, financial data for the ORNL core competencies are summarized in the appendices.

  17. Using Digital Video Production to Meet the Common Core Standards

    ERIC Educational Resources Information Center

    Nichols, Maura

    2012-01-01

    The implementation of the Common Core Standards has just begun and these standards will impact a generation that communicates with technology more than anything else. Texting, cell phones, Facebook, YouTube, Skype, etc. are the ways they speak with their friends and the world. The Common Core Standards recognize this. According to the Common Core…

  18. Core assembly storage structure

    DOEpatents

    Jones, Jr., Charles E.; Brunings, Jay E.

    1988-01-01

    A structure for the storage of core assemblies from a liquid metal-cooled nuclear reactor. The structure comprises an enclosed housing having a substantially flat horizontal top plate, a bottom plate and substantially vertical wall members extending therebetween. A plurality of thimble members extend downwardly through the top plate. Each thimble member is closed at its bottom end and has an open end adjacent said top plate. Each thimble member has a length and diameter greater than that of the core assembly to be stored therein. The housing is provided with an inlet duct for the admission of cooling air and an exhaust duct for the discharge of air therefrom, such that when hot core assemblies are placed in the thimbles, the heat generated will by convection cause air to flow from the inlet duct around the thimbles and out the exhaust duct maintaining the core assemblies at a safe temperature without the necessity of auxiliary powered cooling equipment.

  19. Magnetorotational iron core collapse

    NASA Technical Reports Server (NTRS)

    Symbalisty, E. M. D.

    1984-01-01

    During its final evolutionary stages, a massive star, as considered in current astrophysical theory, undergoes rapid collapse, thereby triggering a sequence of a catastrophic event which results in a Type II supernova explosion. A remnant neutron star or a black hole is left after the explosion. Stellar collapse occurs, when thermonuclear fusion has consumed the lighter elements present. At this stage, the core consists of iron. Difficulties arise regarding an appropriate model with respect to the core collapse. The present investigation is concerned with the evolution of a Type II supernova core including the effects of rotation and magnetic fields. A simple neutrino model is developed which reproduced the spherically symmetric results of Bowers and Wilson (1982). Several two-dimensional computational models of stellar collapse are studied, taking into account a case in which a 15 solar masses iron core was artificially given rotational and magnetic energy.

  20. Contaminated Sediment Core Profiling

    EPA Science Inventory

    Evaluating the environmental risk of sites containing contaminated sediments often poses major challenges due in part to the absence of detailed information available for a given location. Sediment core profiling is often utilized during preliminary environmental investigations ...

  1. INTEGRAL core programme

    NASA Technical Reports Server (NTRS)

    Gehrels, N.; Schoenfelder, V.; Ubertini, P.; Winkler, C.

    1997-01-01

    The International Gamma Ray Astrophysics Laboratory (INTEGRAL) mission is described with emphasis on the INTEGRAL core program. The progress made in the planning activities for the core program is reported on. The INTEGRAL mission has a nominal lifetime of two years with a five year extension option. The observing time will be divided between the core program (between 30 and 35 percent during the first two years) and general observations. The core program consists of three main elements: the deep survey of the Galactic plane in the central radian of the Galaxy; frequent scans of the Galactic plane in the search for transient sources, and pointed observations of several selected sources. The allocation of the observation time is detailed and the sensitivities of the observations are outlined.

  2. Biospecimen Core Resource - TCGA

    Cancer.gov

    The Cancer Genome Atlas (TCGA) Biospecimen Core Resource centralized laboratory reviews and processes blood and tissue samples and their associated data using optimized standard operating procedures for the entire TCGA Research Network.

  3. Core bounce supernovae

    SciTech Connect

    Cooperstein, J.

    1987-01-01

    The gravitational collapse mechanism for Type II supernovae is considered, concentrating on the direct implosion - core bounce - hydrodynamic explosion picture. We examine the influence of the stiffness of the dense matter equation of state and discuss how the shock wave is formed. Its chances of success are determined by the equation of state, general relativistic effects, neutrino transport, and the size of presupernova iron core. 12 refs., 1 tab.

  4. Nuclear core positioning system

    DOEpatents

    Garkisch, Hans D.; Yant, Howard W.; Patterson, John F.

    1979-01-01

    A structural support system for the core of a nuclear reactor which achieves relatively restricted clearances at operating conditions and yet allows sufficient clearance between fuel assemblies at refueling temperatures. Axially displaced spacer pads having variable between pad spacing and a temperature compensated radial restraint system are utilized to maintain clearances between the fuel elements. The core support plates are constructed of metals specially chosen such that differential thermal expansion produces positive restraint at operating temperatures.

  5. Micro coring apparatus

    NASA Technical Reports Server (NTRS)

    Collins, David; Brooks, Marshall; Chen, Paul; Dwelle, Paul; Fischer, Ben

    1989-01-01

    A micro-coring apparatus for lunar exploration applications, that is compatible with the other components of the Walking Mobile Platform, was designed. The primary purpose of core sampling is to gain an understanding of the geological composition and properties of the prescribed environment. This procedure has been used extensively for Earth studies and in limited applications during lunar explorations. The corer is described and analyzed for effectiveness.

  6. MCNP LWR Core Generator

    SciTech Connect

    Fischer, Noah A.

    2012-08-14

    The reactor core input generator allows for MCNP input files to be tailored to design specifications and generated in seconds. Full reactor models can now easily be created by specifying a small set of parameters and generating an MCNP input for a full reactor core. Axial zoning of the core will allow for density variation in the fuel and moderator, with pin-by-pin fidelity, so that BWR cores can more accurately be modeled. LWR core work in progress: (1) Reflectivity option for specifying 1/4, 1/2, or full core simulation; (2) Axial zoning for moderator densities that vary with height; (3) Generating multiple types of assemblies for different fuel enrichments; and (4) Parameters for specifying BWR box walls. Fuel pin work in progress: (1) Radial and azimuthal zoning for generating further unique materials in fuel rods; (2) Options for specifying different types of fuel for MOX or multiple burn assemblies; (3) Additional options for replacing fuel rods with burnable poison rods; and (4) Control rod/blade modeling.

  7. Emergency core cooling system

    DOEpatents

    Schenewerk, William E.; Glasgow, Lyle E.

    1983-01-01

    A liquid metal cooled fast breeder reactor provided with an emergency core cooling system includes a reactor vessel which contains a reactor core comprising an array of fuel assemblies and a plurality of blanket assemblies. The reactor core is immersed in a pool of liquid metal coolant. The reactor also includes a primary coolant system comprising a pump and conduits for circulating liquid metal coolant to the reactor core and through the fuel and blanket assemblies of the core. A converging-diverging venturi nozzle with an intermediate throat section is provided in between the assemblies and the pump. The intermediate throat section of the nozzle is provided with at least one opening which is in fluid communication with the pool of liquid sodium. In normal operation, coolant flows from the pump through the nozzle to the assemblies with very little fluid flowing through the opening in the throat. However, when the pump is not running, residual heat in the core causes fluid from the pool to flow through the opening in the throat of the nozzle and outwardly through the nozzle to the assemblies, thus providing a means of removing decay heat.

  8. Gravitational Infall in Molecular Cloud Cores

    NASA Astrophysics Data System (ADS)

    Ziegler, Mareike

    The detection and quantification of gravitational infall in molecular cloud cores is an important task for developing a self-consistent theory of star formation. First steps towards a quantification of the collapse have been performed by Larson (1981), who examined the line width-size relation of several molecular clouds and determined from their velocity dispersion the deviations from virial equilibrium. Soon after that, observational improvements made it possible to study this relation not only for molecular clouds but also in particular for its cores. Nowadays, increased observational performance allows to resolve the core region in detail (Barranco et al, 1998). Line-of-sight velocity profiles can therefore be analyzed dependend on their radial distance from the core's center. Myers et al. (1996) pointed out that observations of optically thick tracer profiles can be used to derive the strength of collapse motions. On the basis of our semi-analytical model we suggest here a further method how to determine the gravitational infall from the radial velocity gradients of optically thin tracers inside a core. Moreover, we discuss other impacts on the line-of-sight profile due to additional effects inside the core, like for instance rotation.

  9. Composition of Apollo 17 core 76001

    NASA Technical Reports Server (NTRS)

    Korotev, Randy L.; Bishop, Kaylynn M.

    1993-01-01

    Core 76001 is a single drive tube containing a column of regolith taken at the base of the North Massif, station 6, Apollo 17. The core material is believed to have accumulated through slow downslope mass wasting from the massif. As a consequence, the core soil is mature throughout its length. Results of INAA for samples taken every half centimeter along the length of the core indicate that there is only minor systematic compositional variation with depth. Concentrations of elements primarily associated with mare basalt (Sc, Fe) and noritic impact melt breccia (Sm) decrease slightly with depth, particularly between 20 cm and the bottom of the core at 32 cm depth. This is consistent with petrographic studies that indicate a greater proportion of basalt and melt breccia in the top part of the core. However, Sm/Sc and La/Sm ratios are remarkably constant with depth, indicating no variation in the ratio of mare material to Sm-rich highlands material with depth. Other than these subtle changes, there is no compositional evidence for the two stratigraphic units (0-20 cm and 20-32 cm) defined on the basis of modal petrography, although all samples with anomalously high Ni concentrations (Fe-Ni metal nuggets) occur above 20 cm depth.

  10. Combustion and Engine-Core Noise

    NASA Astrophysics Data System (ADS)

    Ihme, Matthias

    2017-01-01

    The implementation of advanced low-emission aircraft engine technologies and the reduction of noise from airframe, fan, and jet exhaust have made noise contributions from an engine core increasingly important. Therefore, meeting future ambitious noise-reduction goals requires the consideration of engine-core noise. This article reviews progress on the fundamental understanding, experimental analysis, and modeling of engine-core noise; addresses limitations of current techniques; and identifies opportunities for future research. After identifying core-noise contributions from the combustor, turbomachinery, nozzles, and jet exhaust, they are examined in detail. Contributions from direct combustion noise, originating from unsteady combustion, and indirect combustion noise, resulting from the interaction of flow-field perturbations with mean-flow variations in turbine stages and nozzles, are analyzed. A new indirect noise-source contribution arising from mixture inhomogeneities is identified by extending the theory. Although typically omitted in core-noise analysis, the impact of mean-flow variations and nozzle-upstream perturbations on the jet-noise modulation is examined, providing potential avenues for future core-noise mitigation.

  11. Hybrid Analysis of Engine Core Noise

    NASA Astrophysics Data System (ADS)

    O'Brien, Jeffrey; Kim, Jeonglae; Ihme, Matthias

    2015-11-01

    Core noise, or the noise generated within an aircraft engine, is becoming an increasing concern for the aviation industry as other noise sources are progressively reduced. The prediction of core noise generation and propagation is especially challenging for computationalists since it involves extensive multiphysics including chemical reaction and moving blades in addition to the aerothermochemical effects of heated jets. In this work, a representative engine flow path is constructed using experimentally verified geometries to simulate the physics of core noise. A combustor, single-stage turbine, nozzle and jet are modeled in separate calculations using appropriate high fidelity techniques including LES, actuator disk theory and Ffowcs-Williams Hawkings surfaces. A one way coupling procedure is developed for passing fluctuations downstream through the flowpath. This method effectively isolates the core noise from other acoustic sources, enables straightforward study of the interaction between core noise and jet exhaust, and allows for simple distinction between direct and indirect noise. The impact of core noise on the farfield jet acoustics is studied extensively and the relative efficiency of different disturbance types and shapes is examined in detail.

  12. The expanded FindCore method for identification of a core atom set for assessment of protein structure prediction.

    PubMed

    Snyder, David A; Grullon, Jennifer; Huang, Yuanpeng J; Tejero, Roberto; Montelione, Gaetano T

    2014-02-01

    Maximizing the scientific impact of NMR-based structure determination requires robust and statistically sound methods for assessing the precision of NMR-derived structures. In particular, a method to define a core atom set for calculating superimpositions and validating structure predictions is critical to the use of NMR-derived structures as targets in the CASP competition. FindCore (Snyder and Montelione, Proteins 2005;59:673-686) is a superimposition independent method for identifying a core atom set and partitioning that set into domains. However, as FindCore optimizes superimposition by sensitively excluding not-well-defined atoms, the FindCore core may not comprise all atoms suitable for use in certain applications of NMR structures, including the CASP assessment process. Adapting the FindCore approach to assess predicted models against experimental NMR structures in CASP10 required modification of the FindCore method. This paper describes conventions and a standard protocol to calculate an "Expanded FindCore" atom set suitable for validation and application in biological and biophysical contexts. A key application of the Expanded FindCore method is to identify a core set of atoms in the experimental NMR structure for which it makes sense to validate predicted protein structure models. We demonstrate the application of this Expanded FindCore method in characterizing well-defined regions of 18 NMR-derived CASP10 target structures. The Expanded FindCore protocol defines "expanded core atom sets" that match an expert's intuition of which parts of the structure are sufficiently well defined to use in assessing CASP model predictions. We also illustrate the impact of this analysis on the CASP GDT assessment scores.

  13. The Impact of Prostate Volume, Number of Biopsy Cores and American Urological Association Symptom Score on the Sensitivity of Cancer Detection Using the Prostate Cancer Prevention Trial Risk Calculator

    PubMed Central

    Ankerst, Donna P.; Till, Cathee; Boeck, Andreas; Goodman, Phyllis; Tangen, Catherine M.; Feng, Ziding; Partin, Alan W.; Chan, Daniel W.; Sokoll, Lori; Kagan, Jacob; Wei, John T.; Thompson, Ian M.

    2013-01-01

    Purpose We assessed the independent predictive value of prostate volume, number of biopsy cores and AUASS (American Urological Association symptom score) compared to risk factors included in the PCPTRC (Prostate Cancer Prevention Trial risk calculator for prostate cancer) and PCPTHG (Prostate Cancer Prevention Trial risk calculator for high grade cancer [Gleason grade 7 or greater]). Materials and Methods Of 5,519 PCPT (Prostate Cancer Prevention Trial) participants the 4,958 used to construct the PCPTRC with AUASS and prostate specific antigen 10 ng/ml or less were included on logistic regression analysis. Risk algorithms were evaluated in 571 EDRN (Early Detection Research Network) participants using the ROC AUC. Results A total of 1,094 participants (22.1%) had prostate cancer, of whom 232 (21.2%) had high grade disease. For prostate cancer prediction higher prostate specific antigen, abnormal digital rectal examination, family history of prostate cancer and number of cores were associated with increased risk, while volume was associated with decreased risk. Excluding prostate volume and number of cores, a history of negative biopsy and increased AUASS were also associated with lower risk. For high grade cancer higher prostate specific antigen, abnormal digital rectal examination, black race and number of cores were associated with increased risk and volume, while AUASS was associated with decreased risk. The AUC of the PCPTRC adjusted for volume and number of cores was 72.7% using EDRN data and 68.2% when adjusted for AUASS alone vs 67.6% for the PCPTRC. For high grade disease the AUC was 74.8% and 74.0%, respectively, vs 73.5% for the PCPTHG. Conclusions Adjusted PCPT risk calculators for volume, number of cores and AUASS improve cancer detection. PMID:23313212

  14. Core Noise - Increasing Importance

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.

    2011-01-01

    This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015, 2020, and 2025 timeframes; turbofan design trends and their aeroacoustic implications; the emerging importance of core noise and its relevance to the SFW Reduced-Perceived-Noise Technical Challenge; and the current research activities in the core-noise area, with additional details given about the development of a high-fidelity combustor-noise prediction capability as well as activities supporting the development of improved reduced-order, physics-based models for combustor-noise prediction. The need for benchmark data for validation of high-fidelity and modeling work and the value of a potential future diagnostic facility for testing of core-noise-reduction concepts are indicated. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The SFW Reduced-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries. This reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. Noise generated in the jet engine core, by sources such as the compressor, combustor, and turbine, can be a significant contribution to the overall noise signature at low-power conditions, typical of approach flight. At high engine power during takeoff, jet and fan noise have traditionally dominated over core noise. However, current design trends and expected technological advances in engine-cycle design as well as noise-reduction methods are likely to reduce non-core noise even at engine-power points higher than approach. In addition, future low-emission combustor

  15. Recent developments in pressure coring

    SciTech Connect

    McFall, A. L.

    1980-01-01

    The current rapid growth in the number of enhanced oil and gas recovery projects has created a strong demand for reservoir data such as true residual oil saturations. The companies providing pressure coring services have moved to fill this need. Two recent developments have emerged with the potential of significantly improving the present performance of pressure coring. Coring bits utilizing synthetic diamond cutters have demonstrated coring rates of one-foot per minute while improving core recovery. It is also apparent that cores of a near-unconsolidated nature are more easily recovered. In addition, a special low invasion fluid that is placed in the core retriever has demonstrated reduced core washing by the drilling mud and a decrease in the complexity of preparing cores for analysis. This paper describes the design, laboratory, and field testing efforts that led to these coring improvements. Also, experience in utilizing these developments while recovering over 100 cores is discussed.

  16. Pressure Core Characterization

    NASA Astrophysics Data System (ADS)

    Santamarina, J. C.

    2014-12-01

    Natural gas hydrates form under high fluid pressure and low temperature, and are found in permafrost, deep lakes or ocean sediments. Hydrate dissociation by depressurization and/or heating is accompanied by a multifold hydrate volume expansion and host sediments with low permeability experience massive destructuration. Proper characterization requires coring, recovery, manipulation and testing under P-T conditions within the stability field. Pressure core technology allows for the reliable characterization of hydrate bearing sediments within the stability field in order to address scientific and engineering needs, including the measurement of parameters used in hydro-thermo-mechanical analyses, and the monitoring of hydrate dissociation under controlled pressure, temperature, effective stress and chemical conditions. Inherent sampling effects remain and need to be addressed in test protocols and data interpretation. Pressure core technology has been deployed to study hydrate bearing sediments at several locations around the world. In addition to pressure core testing, a comprehensive characterization program should include sediment analysis, testing of reconstituted specimens (with and without synthetic hydrate), and in situ testing. Pressure core characterization technology can be used to study other gas-charged formations such as deep sea sediments, coal bed methane and gas shales.

  17. Core Noise Reduction

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.

    2011-01-01

    This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015, 2020, and 2025 timeframes; turbofan design trends and their aeroacoustic implications; the emerging importance of core noise and its relevance to the SFW Reduce-Perceived-Noise Technical Challenge; and the current research activities in the core noise area. Recent work1 on the turbine-transmission loss of combustor noise is briefly described, two2,3 new NRA efforts in the core-noise area are outlined, and an effort to develop CMC-based acoustic liners for broadband noise reduction suitable for turbofan-core application is delineated. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. The Subsonic Fixed Wing Project's Reduce-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries.

  18. Post-impact alteration of the Manson impact structure

    NASA Technical Reports Server (NTRS)

    Crossey, L. J.; Mccarville, P.

    1993-01-01

    Core materials from the Manson impact site (Manson, Iowa) are examined in order to evaluate post-impact alteration processes. Diagenetic interpretation of post-impact events is based on petrologic, mineralogic, and geochemical investigation of core materials including the following: target strata, disturbed and disrupted strata, ejecta, breccias, microbreccias, and impact melt. The diagenetic study utilizes research cores obtained by the continental scientific drilling project (CSDP) at the Manson structure, as well as core and cuttings of related materials. Samples include impactites (breccias, microbreccias, and melt material), crater fill material (sedimentary clast breccias), disturbed and disrupted target rocks, and reference target material (Amoco Eisheid No. 1 materials). The study of multiple cores will permit development of a regional picture of post-impact thermal history. The specific objectives are as follows: (1) provide a detailed description of authigenic and alteration mineralogy from diverse lithologies encountered in research drill cores at the Manson impact structure, and (2) identify and relate significant post-impact mineral alteration to post-impact thermal regime (extent and duration). Results will provide mineralogical and geochemical constraints on models for post-impact processes including the following: infilling of the crater depression; cooling and hydrothermal alteration of melt rocks; and subsequent long-term, low-temperature alteration of target rocks, breccias, and melt rocks. Preliminary petrologic and x-ray diffraction examination of fracture linings and void fillings from research core M1 indicate the presence of quartz, chlorite, mixed-layer clays, gypsum/anhydrite, calcite, and minor pyrite.

  19. Molten core retention assembly

    DOEpatents

    Lampe, Robert F.

    1976-06-22

    Molten fuel produced in a core overheating accident is caught by a molten core retention assembly consisting of a horizontal baffle plate having a plurality of openings therein, heat exchange tubes having flow holes near the top thereof mounted in the openings, and a cylindrical, imperforate baffle attached to the plate and surrounding the tubes. The baffle assembly is supported from the core support plate of the reactor by a plurality of hanger rods which are welded to radial beams passing under the baffle plate and intermittently welded thereto. Preferably the upper end of the cylindrical baffle terminates in an outwardly facing lip to which are welded a plurality of bearings having slots therein adapted to accept the hanger rods.

  20. Earth's core iron

    NASA Astrophysics Data System (ADS)

    Geophysicist J. Michael Brown of Texas A & M University noted recently at the Spring AGU Meeting in Baltimore that the structure and phase of metallic iron at pressures of the earth's inner core (approximately 3.3 Mbar) could have great significance in defining geometrical aspects of the core itself. Brown worked at the Los Alamos Scientific Laboratory with R.B. McQueen to redetermine the phase relations of metallic iron in a series of new shock-wave experiments. They found the melting point of iron at conditions equal to those at the boundary of the earth's outer (liquid) and inner (solid) cores to be 6000°±500°C (Geophysical Research Letters, 7, 533-536, 1980).

  1. CORE SATURATION BLOCKING OSCILLATOR

    DOEpatents

    Spinrad, R.J.

    1961-10-17

    A blocking oscillator which relies on core saturation regulation to control the output pulse width is described. In this arrangement an external magnetic loop is provided in which a saturable portion forms the core of a feedback transformer used with the thermionic or semi-conductor active element. A first stationary magnetic loop establishes a level of flux through the saturation portion of the loop. A second adjustable magnet moves the flux level to select a saturation point giving the desired output pulse width. (AEC)

  2. Navagating the Common Core

    ERIC Educational Resources Information Center

    McShane, Michael Q.

    2014-01-01

    This article presents a debate over the Common Core State Standards Initiative as it has rocketed to the forefront of education policy discussions around the country. The author contends that there is value in having clear cross state standards that will clarify the new online and blended learning that the growing use of technology has provided…

  3. Ultrasonic Drilling and Coring

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph

    1998-01-01

    A novel drilling and coring device, driven by a combination, of sonic and ultrasonic vibration, was developed. The device is applicable to soft and hard objects using low axial load and potentially operational under extreme conditions. The device has numerous potential planetary applications. Significant potential for commercialization in construction, demining, drilling and medical technologies.

  4. NUCLEAR REACTOR CORE DESIGN

    DOEpatents

    Mahlmeister, J.E.; Peck, W.S.; Haberer, W.V.; Williams, A.C.

    1960-03-22

    An improved core design for a sodium-cooled, graphitemoderated nuclear reactor is described. The improved reactor core comprises a number of blocks of moderator material, each block being in the shape of a regular prism. A number of channels, extending the length of each block, are disposed around the periphery. When several blocks are placed in contact to form the reactor core, the channels in adjacent blocks correspond with each other to form closed conduits extending the length of the core. Fuel element clusters are disposed in these closed conduits, and liquid coolant is forced through the annulus between the fuel cluster and the inner surface of the conduit. In a preferred embodiment of the invention, the moderator blocks are in the form of hexagonal prisms with longitudinal channels cut into the corners of the hexagon. The main advantage of an "edge-loaded" moderator block is that fewer thermal neutrons are absorbed by the moderator cladding, as compared with a conventional centrally loaded moderator block.

  5. Authentic to the Core

    ERIC Educational Resources Information Center

    Kukral, Nicole; Spector, Stacy

    2012-01-01

    When educators think about what makes learning relevant to students, often they narrow their thinking to electives or career technical education. While these provide powerful opportunities for students to make relevant connections to their learning, they can also create authentic experiences in the core curriculum. In the San Juan Unified School…

  6. Electromagnetic pump stator core

    DOEpatents

    Fanning, Alan W.; Olich, Eugene E.; Dahl, Leslie R.

    1995-01-01

    A stator core for supporting an electrical coil includes a plurality of groups of circumferentially abutting flat laminations which collectively form a bore and perimeter. A plurality of wedges are interposed between the groups, with each wedge having an inner edge and a thicker outer edge. The wedge outer edges abut adjacent ones of the groups to provide a continuous path around the perimeter.

  7. Theory of core excitons

    SciTech Connect

    Dow, J. D.; Hjalmarson, H. P.; Sankey, O. F.; Allen, R. E.; Buettner, H.

    1980-01-01

    The observation of core excitons with binding energies much larger than those of the valence excitons in the same material has posed a long-standing theoretical problem. A proposed solution to this problem is presented, and Frenkel excitons and Wannier excitons are shown to coexist naturally in a single material. (GHT)

  8. Some Core Contested Concepts

    ERIC Educational Resources Information Center

    Chomsky, Noam

    2015-01-01

    Core concepts of language are highly contested. In some cases this is legitimate: real empirical and conceptual issues arise. In other cases, it seems that controversies are based on misunderstanding. A number of crucial cases are reviewed, and an approach to language is outlined that appears to have strong conceptual and empirical motivation, and…

  9. Core Directions in HRD.

    ERIC Educational Resources Information Center

    1996

    This document consists of four papers presented at a symposium on core directions in human resource development (HRD) moderated by Verna Willis at the 1996 conference of the Academy of Human Resource Development. "Reengineering the Organizational HRD Function: Two Case Studies" (Neal Chalofsky) reports an action research study in which…

  10. Core Geometry Manual.

    ERIC Educational Resources Information Center

    Hirata, Li Ann

    Core Geometry is a course offered in the Option Y sequence of the high school mathematics program described by the Hawaii State Department of Education's guidelines. The emphasis of this course is on the general awareness and use of the relationships among points, lines, and figures in planes and space. This sample course is based on the…

  11. Life from the core

    NASA Astrophysics Data System (ADS)

    Doglioni, Carlo; Coleman, Max; Pignatti, Johannes; Glassmeier, Karl-Heinz

    2010-05-01

    Life on Earth is the result of the chaotic combination of several independent chemical and physical parameters. One of them is the shield from ionizing radiation exerted by the atmosphere and the Earth's magnetic field. We hypothesise that the first few billion years of the Earth's history, dominated by bacteria, were characterized by stronger ionizing radiation. Bacteria can survive under such conditions better than any other organism. During the Archean and early Proterozoic the shield could have been weaker, allowing the development of only a limited number of species, more resistant to the external radiation. The Cambrian explosion of life could have been enhanced by the gradual growth of the solid inner core, which was not existent possibly before 1 Ga. The cooling of the Earth generated the solidification of the iron alloy in the center of the planet. As an hypothesis, before the crystallization of the core, the turbulence in the liquid core could have resulted in a lower or different magnetic field from the one we know today, being absent the relative rotation between inner and external core.

  12. The Earth's Core.

    ERIC Educational Resources Information Center

    Jeanloz, Raymond

    1983-01-01

    The nature of the earth's core is described. Indirect evidence (such as that determined from seismological data) indicates that it is an iron alloy, solid toward its center but otherwise liquid. Evidence also suggests that it is the turbulent flow of the liquid that generates the earth's magnetic field. (JN)

  13. Modeling Core Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Mezzacappa, Anthony

    2017-01-01

    Core collapse supernovae, or the death throes of massive stars, are general relativistic, neutrino-magneto-hydrodynamic events. The core collapse supernova mechanism is still not in hand, though key components have been illuminated, and the potential for multiple mechanisms for different progenitors exists. Core collapse supernovae are the single most important source of elements in the Universe, and serve other critical roles in galactic chemical and thermal evolution, the birth of neutron stars, pulsars, and stellar mass black holes, the production of a subclass of gamma-ray bursts, and as potential cosmic laboratories for fundamental nuclear and particle physics. Given this, the so called ``supernova problem'' is one of the most important unsolved problems in astrophysics. It has been fifty years since the first numerical simulations of core collapse supernovae were performed. Progress in the past decade, and especially within the past five years, has been exponential, yet much work remains. Spherically symmetric simulations over nearly four decades laid the foundation for this progress. Two-dimensional modeling that assumes axial symmetry is maturing. And three-dimensional modeling, while in its infancy, has begun in earnest. I will present some of the recent work from the ``Oak Ridge'' group, and will discuss this work in the context of the broader work by other researchers in the field. I will then point to future requirements and challenges. Connections with other experimental, observational, and theoretical efforts will be discussed, as well.

  14. University City Core Plan.

    ERIC Educational Resources Information Center

    Philadelphia City Planning Commission, PA.

    A redevelopment plan for an urban core area of about 300 acres was warranted by--(1) unsuitable building conditions, (2) undesirable land usage, and (3) faulty traffic circulation. The plan includes expansion of two universities and creation of a regional science center, high school, and medical center. Guidelines for proposed land use and zoning…

  15. The Tom Core Complex

    PubMed Central

    Ahting, Uwe; Thun, Clemens; Hegerl, Reiner; Typke, Dieter; Nargang, Frank E.; Neupert, Walter; Nussberger, Stephan

    1999-01-01

    Translocation of nuclear-encoded preproteins across the outer membrane of mitochondria is mediated by the multicomponent transmembrane TOM complex. We have isolated the TOM core complex of Neurospora crassa by removing the receptors Tom70 and Tom20 from the isolated TOM holo complex by treatment with the detergent dodecyl maltoside. It consists of Tom40, Tom22, and the small Tom components, Tom6 and Tom7. This core complex was also purified directly from mitochondria after solubilization with dodecyl maltoside. The TOM core complex has the characteristics of the general insertion pore; it contains high-conductance channels and binds preprotein in a targeting sequence-dependent manner. It forms a double ring structure that, in contrast to the holo complex, lacks the third density seen in the latter particles. Three-dimensional reconstruction by electron tomography exhibits two open pores traversing the complex with a diameter of ∼2.1 nm and a height of ∼7 nm. Tom40 is the key structural element of the TOM core complex. PMID:10579717

  16. Nucleosome Core Particle

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Nucleosome Core Particle grown on STS-81. The fundamental structural unit of chromatin and is the basis for organization within the genome by compaction of DNA within the nucleus of the cell and by making selected regions of chromosomes available for transcription and replication. Principal Investigator's are Dr. Dan Carter and Dr. Gerard Bunick of New Century Pharmaceuticals.

  17. From Context to Core

    ERIC Educational Resources Information Center

    Campus Technology, 2008

    2008-01-01

    At Campus Technology 2008, Arizona State University Technology Officer Adrian Sannier mesmerized audiences with his mandate to become more efficient by doing only the "core" tech stuff--and getting someone else to slog through the context. This article presents an excerpt from Sannier's hour-long keynote address at Campus Technology '08. Sannier…

  18. Lunar Polar Coring Lander

    NASA Technical Reports Server (NTRS)

    Angell, David; Bealmear, David; Benarroche, Patrice; Henry, Alan; Hudson, Raymond; Rivellini, Tommaso; Tolmachoff, Alex

    1990-01-01

    Plans to build a lunar base are presently being studied with a number of considerations. One of the most important considerations is qualifying the presence of water on the Moon. The existence of water on the Moon implies that future lunar settlements may be able to use this resource to produce things such as drinking water and rocket fuel. Due to the very high cost of transporting these materials to the Moon, in situ production could save billions of dollars in operating costs of the lunar base. Scientists have suggested that the polar regions of the Moon may contain some amounts of water ice in the regolith. Six possible mission scenarios are suggested which would allow lunar polar soil samples to be collected for analysis. The options presented are: remote sensing satellite, two unmanned robotic lunar coring missions (one is a sample return and one is a data return only), two combined manned and robotic polar coring missions, and one fully manned core retrieval mission. One of the combined manned and robotic missions has been singled out for detailed analysis. This mission proposes sending at least three unmanned robotic landers to the lunar pole to take core samples as deep as 15 meters. Upon successful completion of the coring operations, a manned mission would be sent to retrieve the samples and perform extensive experiments of the polar region. Man's first step in returning to the Moon is recommended to investigate the issue of lunar polar water. The potential benefits of lunar water more than warrant sending either astronauts, robots or both to the Moon before any permanent facility is constructed.

  19. Support the Common Core with the Right Instructional Materials

    ERIC Educational Resources Information Center

    Leifer, Rachel; Udall, Denis

    2014-01-01

    Strong instructional materials are crucial to realizing the promise of the Common Core State Standards. Research suggests that the choice of instructional materials can have an impact as large as or larger than the impact of teacher quality. Unfortunately, many popular textbooks are not aligned to the new standards, leaving educators scrambling.…

  20. A Core Journal Decision Model Based on Weighted Page Rank

    ERIC Educational Resources Information Center

    Wang, Hei-Chia; Chou, Ya-lin; Guo, Jiunn-Liang

    2011-01-01

    Purpose: The paper's aim is to propose a core journal decision method, called the local impact factor (LIF), which can evaluate the requirements of the local user community by combining both the access rate and the weighted impact factor, and by tracking citation information on the local users' articles. Design/methodology/approach: Many…

  1. Coring Methane Hydrate by using Hybrid Pressure Coring System of D/V Chikyu

    NASA Astrophysics Data System (ADS)

    Kubo, Y.; Mizuguchi, Y.; Inagaki, F.; Eguchi, N.; Yamamoto, K.

    2013-12-01

    Pressure coring is a technique to keep in-situ conditions in recovering sub-seafloor sediment samples, which are potentially rich in soluble or hydrated gas. In regular core sampling, gas fractions are easily lost through the changes in the pressure and temperature during core recovery, and it has significant impact on the chemical components of the sample. Rapid degassing may also cause critical damages of original structures. To study original characteristics of gaseous sub-seafloor sediment, a new Hybrid Pressure Coring System (Hybrid PCS) was developed for the D/V Chikyu operation by adapting some of the existing pressure sampling technologies. Hybrid PCS is composed of three main parts: top section for the wireline operation, middle section for the accumulator and pressure controlling system, and the bottom section for the autoclave chamber. The design concept is based on that of Pressure Core Sampler used in Ocean Drilling Program, and of Pressure Temperature Core Sampler (PTCS) and Non-cooled PTCS of Japan Oil, Gas and Metals National Corporation (JOGMEC). Several modifications were made including that on the ball valve, which operates to close the autoclave after coring. The core samples are 51 mm in diameter and up to 3.5 m in length. The system is combined with the Extented Shoe Coring System on the Chikyu and best suited for coring of semi-consolidated formation up to about 3400 m from the sea level. Sample autoclave is compatible with Pressure Core Analysis and Transfer System (PCATS) of Geotek Ltd for sub-sampling and analysis under in-situ pressure. The analysis in PCATS includes X-ray CT scan and core logging with P-wave velocity and gamma density. Depressurization provides accurate volume of gas and its sub-sampling. Hybrid PCS was first tested during the Chikyu Exp. 906 at a submarine mud-volcano in the Nankai Trough. A 0.9 m of hydrate rich material was recovered from the summit (water depth: 2000 m) and the intact hydrate structure was observed

  2. Damage tolerance of a composite sandwich with interleaved foam core

    NASA Technical Reports Server (NTRS)

    Ishai, Ori; Hiel, Clement

    1992-01-01

    A composite sandwich panel consisting of carbon fiber-reinforced plastic (CFRP) skins and a syntactic foam core was selected as an appropriate structural concept for the design of wind tunnel compressor blades. Interleaving of the core with tough interlayers was done to prevent core cracking and to improve damage tolerance of the sandwich. Simply supported sandwich beam specimens were subjected to low-velocity drop-weight impacts as well as high velocity ballistic impacts. The performance of the interleaved core sandwich panels was characterized by localized skin damage and minor cracking of the core. Residual compressive strength (RCS) of the skin, which was derived from flexural test, shows the expected trend of decreasing with increasing size of the damage, impact energy, and velocity. In the case of skin damage, RCS values of around 50 percent of the virgin interleaved reference were obtained at the upper impact energy range. Based on the similarity between low-velocity and ballistic-impact effects, it was concluded that impact energy is the main variable controlling damage and residual strength, where as velocity plays a minor role.

  3. Application of Core Dynamics Modeling to Core-Mantle Interactions

    NASA Technical Reports Server (NTRS)

    Kuang, Weijia

    2003-01-01

    Observations have demonstrated that length of day (LOD) variation on decadal time scales results from exchange of axial angular momentum between the solid mantle and the core. There are in general four core-mantle interaction mechanisms that couple the core and the mantle. Of which, three have been suggested likely the dominant coupling mechanism for the decadal core-mantle angular momentum exchange, namely, gravitational core-mantle coupling arising from density anomalies in the mantle and in the core (including the inner core), the electromagnetic coupling arising from Lorentz force in the electrically conducting lower mantle (e.g. D-layer), and the topographic coupling arising from non-hydrostatic pressure acting on the core-mantle boundary (CMB) topography. In the past decades, most effort has been on estimating the coupling torques from surface geomagnetic observations (kinematic approach), which has provided insights on the core dynamical processes. In the meantime, it also creates questions and concerns on approximations in the studies that may invalidate the corresponding conclusions. The most serious problem is perhaps the approximations that are inconsistent with dynamical processes in the core, such as inconsistencies between the core surface flow beneath the CMB and the CMB topography, and that between the D-layer electric conductivity and the approximations on toroidal field at the CMB. These inconsistencies can only be addressed with numerical core dynamics modeling. In the past few years, we applied our MoSST (Modular, Scalable, Self-consistent and Three-dimensional) core dynamics model to study core-mantle interactions together with geodynamo simulation, aiming at assessing the effect of the dynamical inconsistencies in the kinematic studies on core-mantle coupling torques. We focus on topographic and electromagnetic core-mantle couplings and find that, for the topographic coupling, the consistency between the core flow and the CMB topography is

  4. Expression of viral polymerase and phosphorylation of core protein determine core and capsid localization of the human hepatitis B virus.

    PubMed

    Deroubaix, Aurélie; Osseman, Quentin; Cassany, Aurélia; Bégu, Dominique; Ragues, Jessica; Kassab, Somar; Lainé, Sébastien; Kann, Michael

    2015-01-01

    Biopsies from patients show that hepadnaviral core proteins and capsids - collectively called core - are found in the nucleus and cytoplasm of infected hepatocytes. In the majority of studies, cytoplasmic core localization is related to low viraemia while nuclear core localization is associated with high viral loads. In order to better understand the molecular interactions leading to core localization, we analysed transfected hepatoma cells using immune fluorescence microscopy. We observed that expression of core protein in the absence of other viral proteins led to nuclear localization of core protein and capsids, while expression of core in the context of the other viral proteins resulted in a predominantly cytoplasmic localization. Analysis of which viral partner was responsible for cytoplasmic retention indicated that the HBx, surface proteins and HBeAg had no impact but that the viral polymerase was the major determinant. Further analysis revealed that ϵ, an RNA structure to which the viral polymerase binds, was essential for cytoplasmic retention. Furthermore, we showed that core protein phosphorylation at Ser 164 was essential for the cytoplasmic core localization phenotype, which is likely to explain differences observed between individual cells.

  5. Core Outlet Temperature Study

    SciTech Connect

    Moisseytsev, A.; Hoffman, E.; Majumdar, S.

    2008-07-28

    It is a known fact that the power conversion plant efficiency increases with elevation of the heat addition temperature. The higher efficiency means better utilization of the available resources such that higher output in terms of electricity production can be achieved for the same size and power of the reactor core or, alternatively, a lower power core could be used to produce the same electrical output. Since any nuclear power plant, such as the Advanced Burner Reactor, is ultimately built to produce electricity, a higher electrical output is always desirable. However, the benefits of the higher efficiency and electricity production usually come at a price. Both the benefits and the disadvantages of higher reactor outlet temperatures are analyzed in this work.

  6. Dynamics of core accretion

    DOE PAGES

    Nelson, Andrew F.; Ruffert, Maximilian

    2012-12-21

    In this paper, we perform three-dimensional hydrodynamic simulations of gas flowing around a planetary core of mass Mpl = 10M⊕ embedded in a near Keplerian background flow, using a modified shearing box approximation. We assume an ideal gas behaviour following an equation of state with a fixed ratio of the specific heats, γ = 1.42, consistent with the conditions of a moderate-temperature background disc with solar composition. No radiative heating or cooling is included in the models. We employ a nested grid hydrodynamic code implementing the ‘Piecewise Parabolic Method’ with as many as six fixed nested grids, providing spatial resolutionmore » on the finest grid comparable to the present-day diameters of Neptune and Uranus. We find that a strongly dynamically active flow develops such that no static envelope can form. The activity is not sensitive to plausible variations in the rotation curve of the underlying disc. It is sensitive to the thermodynamic treatment of the gas, as modelled by prescribed equations of state (either ‘locally isothermal’ or ‘locally isentropic’) and the temperature of the background disc material. The activity is also sensitive to the shape and depth of the core's gravitational potential, through its mass and gravitational softening coefficient. Each of these factors influences the magnitude and character of hydrodynamic feedback of the small-scale flow on the background, and we conclude that accurate modelling of such feedback is critical to a complete understanding of the core accretion process. The varying flow pattern gives rise to large, irregular eruptions of matter from the region around the core which return matter to the background flow: mass in the envelope at one time may not be found in the envelope at any later time. No net mass accretion into the envelope is observed over the course of the simulation and none is expected, due to our neglect of cooling. Except in cases of very rapid cooling however, as

  7. Dynamics of core accretion

    SciTech Connect

    Nelson, Andrew F.; Ruffert, Maximilian

    2012-12-21

    In this paper, we perform three-dimensional hydrodynamic simulations of gas flowing around a planetary core of mass Mpl = 10M embedded in a near Keplerian background flow, using a modified shearing box approximation. We assume an ideal gas behaviour following an equation of state with a fixed ratio of the specific heats, γ = 1.42, consistent with the conditions of a moderate-temperature background disc with solar composition. No radiative heating or cooling is included in the models. We employ a nested grid hydrodynamic code implementing the ‘Piecewise Parabolic Method’ with as many as six fixed nested grids, providing spatial resolution on the finest grid comparable to the present-day diameters of Neptune and Uranus. We find that a strongly dynamically active flow develops such that no static envelope can form. The activity is not sensitive to plausible variations in the rotation curve of the underlying disc. It is sensitive to the thermodynamic treatment of the gas, as modelled by prescribed equations of state (either ‘locally isothermal’ or ‘locally isentropic’) and the temperature of the background disc material. The activity is also sensitive to the shape and depth of the core's gravitational potential, through its mass and gravitational softening coefficient. Each of these factors influences the magnitude and character of hydrodynamic feedback of the small-scale flow on the background, and we conclude that accurate modelling of such feedback is critical to a complete understanding of the core accretion process. The varying flow pattern gives rise to large, irregular eruptions of matter from the region around the core which return matter to the background flow: mass in the envelope at one time may not be found in the envelope at any later time. No net mass accretion into the envelope is observed over the course of the simulation and none is expected, due to our neglect of cooling. Except in cases of very rapid cooling

  8. Long Valley Coring Project

    USGS Publications Warehouse

    Sass, John; Finger, John; McConnel, Vicki

    1998-01-01

    In December 1997, the California Energy Commission (CEC) agreed to provide funding for Phase III continued drilling of the Long Valley Exploratory Well (LVEW) near Mammoth Lakes, CA, from its present depth. The CEC contribution of $1 million completes a funding package of $2 million from a variety of sources, which will allow the well to be cored continuously to a depth of between 11,500 and 12,500 feet. The core recovered from Phase III will be crucial to understanding the origin and history of the hydrothermal systems responsible for the filling of fractures in the basement rock. The borehole may penetrate the metamorphic roof of the large magmatic complex that has fed the volcanism responsible for the caldera and subsequent activity.

  9. Geomagnetism of earth's core

    NASA Technical Reports Server (NTRS)

    Benton, E. R.

    1983-01-01

    Instrumentation, analytical methods, and research goals for understanding the behavior and source of geophysical magnetism are reviewed. Magsat, launched in 1979, collected global magnetometer data and identified the main terrestrial magnetic fields. The data has been treated by representing the curl-free field in terms of a scalar potential which is decomposed into a truncated series of spherical harmonics. Solutions to the Laplace equation then extend the field upward or downward from the measurement level through intervening spaces with no source. Further research is necessary on the interaction between harmonics of various spatial scales. Attempts are also being made to analytically model the main field and its secular variation at the core-mantle boundary. Work is also being done on characterizing the core structure, composition, thermodynamics, energetics, and formation, as well as designing a new Magsat or a tethered satellite to be flown on the Shuttle.

  10. Banded electromagnetic stator core

    DOEpatents

    Fanning, Alan W.; Gonzales, Aaron A.; Patel, Mahadeo R.; Olich, Eugene E.

    1996-01-01

    A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups.

  11. Banded electromagnetic stator core

    DOEpatents

    Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

    1994-04-05

    A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figures.

  12. Banded electromagnetic stator core

    DOEpatents

    Fanning, Alan W.; Gonzales, Aaron A.; Patel, Mahadeo R.; Olich, Eugene E.

    1994-01-01

    A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups.

  13. Banded electromagnetic stator core

    DOEpatents

    Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

    1996-06-11

    A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figs.

  14. Toroidal core winder

    DOEpatents

    Potthoff, Clifford M.

    1978-01-01

    The disclosure is directed to an apparatus for placing wire windings on a toroidal body, such as a transformer core, having an orifice in its center. The apparatus comprises a wire storage spool, a wire loop holding continuous belt maintained in a C-shaped loop by a belt supporting structure and provision for turning the belt to place and tighten loops of wire on a toroidal body, which is disposed within the gap of the C-shaped belt loop.

  15. Electromagnetic pump stator core

    DOEpatents

    Fanning, A.W.; Olich, E.E.; Dahl, L.R.

    1995-01-17

    A stator core for supporting an electrical coil includes a plurality of groups of circumferentially abutting flat laminations which collectively form a bore and perimeter. A plurality of wedges are interposed between the groups, with each wedge having an inner edge and a thicker outer edge. The wedge outer edges abut adjacent ones of the groups to provide a continuous path around the perimeter. 21 figures.

  16. Fissioning Plasma Core Reactor

    NASA Technical Reports Server (NTRS)

    Albright, Dennis; Butler, Carey; West, Nicole; Cole, John W. (Technical Monitor)

    2002-01-01

    Institute for Scientific Research, Inc. (ISR) research program consist of: 1.Study core physics by adapting existing codes: MCNP4C - Monte Carlo code; COMBINE/VENTURE - diffusion theory; SCALE4 - Monte Carlo, with many utility codes. 2. Determine feasibility and study major design parameters: fuel selection, temperature and reflector sizing. 3. Study reactor kinetics: develop QCALC1 to model point kinetics; study dynamic behavior of the power release.

  17. Variable depth core sampler

    DOEpatents

    Bourgeois, Peter M.; Reger, Robert J.

    1996-01-01

    A variable depth core sampler apparatus comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member.

  18. Some core contested concepts.

    PubMed

    Chomsky, Noam

    2015-02-01

    Core concepts of language are highly contested. In some cases this is legitimate: real empirical and conceptual issues arise. In other cases, it seems that controversies are based on misunderstanding. A number of crucial cases are reviewed, and an approach to language is outlined that appears to have strong conceptual and empirical motivation, and to lead to conclusions about a number of significant issues that differ from some conventional beliefs.

  19. Core-collapse Supernovae

    SciTech Connect

    Hix, William Raphael; Lentz, E. J.; Baird, Mark L; Chertkow, Merek A; Lee, Ching-Tsai; Blondin, J. M.; Bruenn, S. W.; Messer, Bronson; Mezzacappa, Anthony

    2013-01-01

    Marking the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae bring together physics at a wide range in spatial scales, from kilometer-sized hydrodynamic motions (growing to gigameter scale) down to femtometer scale nuclear reactions. Carrying 10$^{51}$ ergs of kinetic energy and a rich-mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up ourselves and our solar system. We will discuss our emerging understanding of the convectively unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino-radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Recent multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of how supernovae explode. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

  20. GEOS-CORE

    SciTech Connect

    2014-06-24

    GEOS-CORE is a code that integrates open source Libraries for linear algebra and I/O with two main LLNL-written components: (i) a set of standard finite, discrete, and discontinuous displacement element physics solvers for resolving Darcy fluid flow, explicit mechanics, implicit mechanics, and fluid-mediated fracturing, including resolution of physical behaviors both implicitly and explicitly, and (ii) a MPI-based parallelization implementation for use on generic HPC distributed memory architectures. The resultant code can be used alone for linearly elastic and quasistatic damage problems; problems involving hydraulic fracturing, where the mesh topology is dynamically changed; and general granular materials behavior. The key application domain is for low-rate stimulation and fracture control in subsurface reservoirs (e.g., enhanced geothermal sites and unconventional shale gas stimulation). GEOS-CORE also has interfaces to call external libraries for, e.g., material models and equations fo state; however, LLNL-developed EOS and material models, beyond the aforementioned linear elastic and quasi-static damage models, will not be part of the current release. GEOS-CORE's secondary applications include granular materials behavior under different load paths.

  1. 33. BENCH CORE STATION, GREY IRON FOUNDRY CORE ROOM WHERE ...

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

    33. BENCH CORE STATION, GREY IRON FOUNDRY CORE ROOM WHERE CORE MOLDS WERE HAND FILLED AND OFTEN PNEUMATICALLY COMPRESSED WITH A HAND-HELD RAMMER BEFORE THEY WERE BAKED. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  2. Selenium semiconductor core optical fibers

    SciTech Connect

    Tang, G. W.; Qian, Q. Peng, K. L.; Wen, X.; Zhou, G. X.; Sun, M.; Chen, X. D.; Yang, Z. M.

    2015-02-15

    Phosphate glass-clad optical fibers containing selenium (Se) semiconductor core were fabricated using a molten core method. The cores were found to be amorphous as evidenced by X-ray diffraction and corroborated by Micro-Raman spectrum. Elemental analysis across the core/clad interface suggests that there is some diffusion of about 3 wt % oxygen in the core region. Phosphate glass-clad crystalline selenium core optical fibers were obtained by a postdrawing annealing process. A two-cm-long crystalline selenium semiconductor core optical fibers, electrically contacted to external circuitry through the fiber end facets, exhibit a three times change in conductivity between dark and illuminated states. Such crystalline selenium semiconductor core optical fibers have promising utility in optical switch and photoconductivity of optical fiber array.

  3. Dark matter cores all the way down

    NASA Astrophysics Data System (ADS)

    Read, J. I.; Agertz, O.; Collins, M. L. M.

    2016-07-01

    We use high-resolution simulations of isolated dwarf galaxies to study the physics of dark matter cusp-core transformations at the edge of galaxy formation: M200 = 107-109 M⊙. We work at a resolution (˜4 pc minimum cell size; ˜250 M⊙ per particle) at which the impact from individual supernovae explosions can be resolved, becoming insensitive to even large changes in our numerical `sub-grid' parameters. We find that our dwarf galaxies give a remarkable match to the stellar light profile; star formation history; metallicity distribution function; and star/gas kinematics of isolated dwarf irregular galaxies. Our key result is that dark matter cores of size comparable to the stellar half-mass radius r1/2 always form if star formation proceeds for long enough. Cores fully form in less than 4 Gyr for the M200 = 108 M⊙ and ˜14 Gyr for the 109 M⊙ dwarf. We provide a convenient two parameter `CORENFW' fitting function that captures this dark matter core growth as a function of star formation time and the projected stellar half-mass radius. Our results have several implications: (i) we make a strong prediction that if Λcold dark matter is correct, then `pristine' dark matter cusps will be found either in systems that have truncated star formation and/or at radii r > r1/2; (ii) complete core formation lowers the projected velocity dispersion at r1/2 by a factor of ˜2, which is sufficient to fully explain the `too-big-to-fail problem'; and (iii) cored dwarfs will be much more susceptible to tides, leading to a dramatic scouring of the sub-halo mass function inside galaxies and groups.

  4. THE IRON PROJECT & THE RMAX PROJECT: Highly excited Core resonances in photoionzation of Fe XVII and impact on plasma opacities, oscillator strengths of Fe XIV, and nebular abundance of O II

    NASA Astrophysics Data System (ADS)

    Pradhan, Anil; Nahar, Sultana; Palay, Ethan; Eissner, Werner

    2011-05-01

    The aims of the Iron Project and the Rmax Project are detailed study of radiative and collisional processes of astrophysically abundant atoms and ions, mainly iron and iron-peak elements, over a wide energy range, from infra-red to X-rays. We will illustrate the dominance of high energy photoexciation-of-core (PEC) resonances in photoionization of Fe XVII due to strong coupling effects on dipole transition arrays 2p5 --> 2p4 (3 s , 3 d) in the core and examine PEC and non-PEC resonance strengths for their expanded role to incorporate inner-shell excitations for improved opacities. Comparisons show that the currently available cross sections from the Opacity Project are considerably underestimated. For Fe XIV, we present preliminary results from a large scale computation where 747 fine structure levels with n <= 10, l <= 9, and 0.5 <= J <= 9.5, and 71,407 electric dipole allowed fine structure transitions have been obtained. We will also demonstrate the fine structure effects on the collision strengths and in very low energy photoionzation for in nebular oxygen abundance. Partial Supports: NSF, DOE

  5. Hollow-Core Fiber Lamp

    NASA Technical Reports Server (NTRS)

    Yi, Lin (Inventor); Tjoelker, Robert L. (Inventor); Burt, Eric A. (Inventor); Huang, Shouhua (Inventor)

    2016-01-01

    Hollow-core capillary discharge lamps on the millimeter or sub-millimeter scale are provided. The hollow-core capillary discharge lamps achieve an increased light intensity ratio between 194 millimeters (useful) and 254 millimeters (useless) light than conventional lamps. The capillary discharge lamps may include a cone to increase light output. Hollow-core photonic crystal fiber (HCPCF) may also be used.

  6. Sneak in Some Core Subjects

    ERIC Educational Resources Information Center

    Clarke, Lynne

    2011-01-01

    Even if students don't have an aversion to core subjects, they may not see the relationship between the core subjects and their career path. In this article, the author outlines a career path project that can be adapted to work in any career and technical education (CTE) class to highlight the relationship between core subjects and the real world.…

  7. Faculty Supports Communication Core Courses.

    ERIC Educational Resources Information Center

    Kopenhaver, Lillian Lodge; And Others

    1989-01-01

    Asks public relations educators what they think about core classes required for students in their field. Finds they generally support the idea that their students should take core mass communications courses, even if such core courses are developed from a traditional journalism/news-editorial standpoint. (MS)

  8. Mercury's inner core size and core-crystallization regime

    NASA Astrophysics Data System (ADS)

    Dumberry, Mathieu; Rivoldini, Attilio

    2015-03-01

    Earth-based radar observation of Mercury's rotation vector combined with gravity observation by the MESSENGER spacecraft yield a measure of Mercury's moment of inertia and the amplitude of the 88-day libration of its silicate shell. These two geodetic constraints provide information on Mercury's interior structure, including the presence of a fluid core, the radius of the core-mantle boundary and the bulk densities of the core and mantle. In this work, we show how they further provide information on the size of the solid inner core and on the crystallization regime of the fluid core. If Mercury's fluid core is a Fe-FeS alloy with a sulfur concentration on the Fe-rich side of the eutectic, the largest inner core compatible with geodetic observations at the 1σ level is 1325 ± 250 km. Our results further suggest that the crystallization scenario that best fits the geodetic observations involves the formation of Fe-snow within the fluid core, and that this scenario is preferred for models with an iron-poor mantle composition. Consequently, Mercury's dynamo most likely operates in concert with snow formation. For an inner core larger than ∼650 km, snow formation extends to the inner core boundary. If a dynamo cannot be maintained by the dynamics of snow formation, or if such dynamo produces a magnetic field incompatible with observation, Mercury's inner core must then be smaller than 650 km.

  9. Granulation of core particles suitable for film coating by agitation fluidized bed I. Optimum formulation for core particles and development of a novel friability test method.

    PubMed

    Hamashita, Tomohiro; Nakagawa, Yasuo; Aketo, Takao; Watano, Satoru

    2007-08-01

    To prepare powdered medicines without bitter taste, film coating is required to cover the surface of core particles. In this study, effect of formulation and operating conditions of agitation fluidized bed on the core particle properties was investigated. In order to prevent breakage of the core particles during coating process, which sometimes causes variation of drug dissolution rate, addition of maltose syrup powder during the formulation process of the core particles was investigated. Also, a method for friability test in which the core particles were subjected to strong impact was proposed to evaluate strength of the core particles. The friability of the core particles determined by this test method correlated well with the actual friability of the particles during the coating process. Based on this result, we confirmed this novel friability test method could predict the core particle endurance during the coating process.

  10. CANOPEN Controller IP Core

    NASA Astrophysics Data System (ADS)

    Caramia, Maurizio; Montagna, Mario; Furano, Gianluca; Winton, Alistair

    2010-08-01

    This paper will describe the activities performed by Thales Alenia Space Italia supported by the European Space Agency in the definition of a CAN bus interface to be used on Exomars. The final goal of this activity is the development of an IP core, to be used in a slave node, able to manage both the CAN bus Data Link and Application Layer totally in hardware. The activity has been focused on the needs of the EXOMARS mission where devices with different computational performances are all managed by the onboard computer through the CAN bus.

  11. Automated Core Design

    SciTech Connect

    Kobayashi, Yoko; Aiyoshi, Eitaro

    2005-07-15

    Multistate searching methods are a subfield of distributed artificial intelligence that aims to provide both principles for construction of complex systems involving multiple states and mechanisms for coordination of independent agents' actions. This paper proposes a multistate searching algorithm with reinforcement learning for the automatic core design of a boiling water reactor. The characteristics of this algorithm are that the coupling structure and the coupling operation suitable for the assigned problem are assumed and an optimal solution is obtained by mutual interference in multistate transitions using multiagents. Calculations in an actual plant confirmed that the proposed algorithm increased the convergence ability of the optimization process.

  12. Recent Developments and Adaptations in Diamond Wireline Core Drilling Technology

    NASA Astrophysics Data System (ADS)

    Thomas, D. M.; Nielson, D. L.; Howell, B. B.; Pardey, M.

    2001-05-01

    Scientific drilling using diamond wireline technology is presently undergoing a significant expansion and extension of activities that has allowed us to recover geologic samples that have heretofore been technically or financially unattainable. Under the direction and management of DOSECC, a high-capacity hybrid core drilling system was designed and fabricated for the Hawaii Scientific Drilling Project (HSDP) in 1998. This system, the DOSECC Hybrid Coring System (DHCS), has the capacity to recover H-sized core from depths of more than 6 km. In 1999, the DHCS completed the first phase of the HSDP to a depth of 3100 m at a substantially lower cost per foot than any previous scientific borehole to comparable depths and, in the process, established a new depth record for recovery of H-sized wireline core. This system has been offered for use in the Unzen Scientific Drilling Project, the Chicxulub (impact crater) Scientific Drilling Project, and the Geysers Deep Geothermal Reservoir Project. More recently, DOSECC has developed a smaller barge-mounted wireline core drilling system, the GLAD800, that is capable of recovering P-sized sediment core to depths of up to 800 m. The GLAD800 has been successfully deployed on Great Salt Lake and Bear Lake in Utah and is presently being mobilized to Lake Titicaca in South America for an extensive core recovery effort there. The coring capabilities of the GLAD800 system will be available to the global lakes drilling community for acquisition of sediment cores from many of the world's deep lakes for use in calibrating and refining global climate models. Presently under development by DOSECC is a heave-compensation system that will allow us to expand the capabilities of the moderate depth coring system to allow us to collect sediment and bottom core from the shallow marine environment. The design and capabilities of these coring systems will be presented along with a discussion of their potential applications for addressing a range of

  13. Efficient provisioning for multi-core applications with LSF

    NASA Astrophysics Data System (ADS)

    Dal Pra, Stefano

    2015-12-01

    Tier-1 sites providing computing power for HEP experiments are usually tightly designed for high throughput performances. This is pursued by reducing the variety of supported use cases and tuning for performances those ones, the most important of which have been that of singlecore jobs. Moreover, the usual workload is saturation: each available core in the farm is in use and there are queued jobs waiting for their turn to run. Enabling multi-core jobs thus requires dedicating a number of hosts where to run, and waiting for them to free the needed number of cores. This drain-time introduces a loss of computing power driven by the number of unusable empty cores. As an increasing demand for multi-core capable resources have emerged, a Task Force have been constituted in WLCG, with the goal to define a simple and efficient multi-core resource provisioning model. This paper details the work done at the INFN Tier-1 to enable multi-core support for the LSF batch system, with the intent of reducing to the minimum the average number of unused cores. The adopted strategy has been that of dedicating to multi-core a dynamic set of nodes, whose dimension is mainly driven by the number of pending multi-core requests and fair-share priority of the submitting user. The node status transition, from single to multi core et vice versa, is driven by a finite state machine which is implemented in a custom multi-core director script, running in the cluster. After describing and motivating both the implementation and the details specific to the LSF batch system, results about performance are reported. Factors having positive and negative impact on the overall efficiency are discussed and solutions to reduce at most the negative ones are proposed.

  14. PROCESS FOR JACKETING A CORE

    DOEpatents

    Last, G.A.

    1960-07-19

    A process is given for enclosing the uranium core of a nuclear fuel element by placing the core in an aluminum cup and closing the open end of the cup over the core. As the metal of the cup is brought together in a weld over the center of the end of the core, it is extruded inwardly as internal projection into a central recess in the core and outwardly as an external projection. Thus oxide inclusions in the weld of the cup are spread out into the internal and external projections and do not interfere with the integrity of the weld.

  15. Plasma core reactor applications

    NASA Technical Reports Server (NTRS)

    Latham, T. S.; Rodgers, R. J.

    1976-01-01

    Analytical and experimental investigations were conducted to demonstrate the feasibility of fissioning uranium plasma core reactors and to characterize space and terrestrial applications for such reactors. Uranium hexafluoride fuel is injected into core cavities and confined away from the surface by argon buffer gas injected tangentially from the peripheral walls. Radiant heat transfer calculations were performed for a six-cavity reactor configuration. Axial working fluid channels are located along a fraction of each cavity peripheral wall. Results of calculations for outward-directed radiant energy fluxes corresponding to radiating temperatures of 2000 to 5000 K indicate total operating pressures from 80 to 650 atm, centerline temperatures from 6900 to 30,000 K, and total radiated powers from 25 to 2500 MW, respectively. Applications are described for this type of reactor such as (1) high-thrust, high specific impulse space propulsion, (2) highly efficient systems for generation of electricity, and (3) hydrogen or synthetic fuel production systems using the intense radiant energy fluxes.

  16. NEUTRONIC REACTOR CORE

    DOEpatents

    Thomson, W.B.; Corbin, A. Jr.

    1961-07-18

    An improved core for a gas-cooled power reactor which admits gas coolant at high temperatures while affording strong integral supporting structure and efficient moderation of neutrons is described. The multiplicities of fuel elements constituting the critical amassment of fissionable material are supported and confined by a matrix of metallic structure which is interspersed therebetween. Thermal insulation is interposed between substantially all of the metallic matrix and the fuel elements; the insulation then defines the principal conduit system for conducting the coolant gas in heat-transfer relationship with the fuel elements. The metallic matrix itseif comprises a system of ducts through which an externally-cooled hydrogeneous liquid, such as water, is circulated to serve as the principal neutron moderant for the core and conjointly as the principal coolant for the insulated metallic structure. In this way, use of substantially neutron transparent metals, such as aluminum, becomes possible for the supporting structure, despite the high temperatures of the proximate gas. The Aircraft Nuclear Propulsion program's "R-1" reactor design is a preferred embodiment.

  17. Core-tube data logger

    SciTech Connect

    Henfling, J.A.; Normann, R.A.; Knudsen, S.; Drumheller, D.

    1997-01-01

    Wireline core drilling, increasingly used for geothermal exploration, employs a core-tube to capture a rock core sample during drilling. Three types of core-tube data loggers (CTDL) have been built and tested to date by Sandia national Laboratories. They are: (1) temperature-only logger, (2) temperature/inclinometer logger and (3) heat-shielded temperature/inclinometer logger. All were tested during core drilling operations using standard wireline diamond core drilling equipment. While these tools are designed for core-tube deployment, the tool lends itself to be adapted to other drilling modes and equipment. Topics covered in this paper include: (1) description on how the CTDLs are implemented, (2) the components of the system, (3) the type of data one can expect from this type of tool, (4) lessons learned, (5) comparison to its counterpart and (6) future work.

  18. Models of the earth's core

    NASA Technical Reports Server (NTRS)

    Stevenson, D. J.

    1981-01-01

    Combined inferences from seismology, high-pressure experiment and theory, geomagnetism, fluid dynamics, and current views of terrestrial planetary evolution lead to models of the earth's core with five basic properties. These are that core formation was contemporaneous with earth accretion; the core is not in chemical equilibrium with the mantle; the outer core is a fluid iron alloy containing significant quantities of lighter elements and is probably almost adiabatic and compositionally uniform; the more iron-rich inner solid core is a consequence of partial freezing of the outer core, and the energy release from this process sustains the earth's magnetic field; and the thermodynamic properties of the core are well constrained by the application of liquid-state theory to seismic and labroatory data.

  19. Models of the Earth's Core.

    PubMed

    Stevenson, D J

    1981-11-06

    Combined inferences from seismology, high-pressure experiment and theory, geomagnetism, fluid dynamics, and current views of terrestrial planetary evolution lead to models of the earth's core with the following properties. Core formation was contemporaneous with earth accretion; the core is not in chemical equilibrium with the mantle; the outer core is a fluid iron alloy containing significant quantities of lighter elements and is probably almost adiabatic and compositionally uniform; the more iron-rich inner solid core is a consequence of partial freezing of the outer core, and the energy release from this process sustains the earth's magnetic field; and the thermodynamic properties of the core are well constrained by the application of liquid-state theory to seismic and laboratory data.

  20. Axion dark matter: strings and their cores

    SciTech Connect

    Fleury, Leesa; Moore, Guy D.

    2016-01-04

    Axions constitute a well-motivated dark matter candidate, and if PQ symmetry breaking occurred after inflation, it should be possible to make a clean prediction for the relation between the axion mass and the axion dark matter density. We show that axion (or other global) string networks in 3D have a network density that depends logarithmically on the string separation-to-core ratio. This logarithm would be about 10 times larger in axion cosmology than what we can achieve in numerical simulations. We simulate axion production in the early Universe, finding that, for the separation-to-core ratios we can achieve, the changing density of the network has little impact on the axion production efficiency.

  1. Axion dark matter: strings and their cores

    SciTech Connect

    Fleury, Leesa; Moore, Guy D. E-mail: guy.moore@physik.tu-darmstadt.de

    2016-01-01

    Axions constitute a well-motivated dark matter candidate, and if PQ symmetry breaking occurred after inflation, it should be possible to make a clean prediction for the relation between the axion mass and the axion dark matter density. We show that axion (or other global) string networks in 3D have a network density that depends logarithmically on the string separation-to-core ratio. This logarithm would be about 10 times larger in axion cosmology than what we can achieve in numerical simulations. We simulate axion production in the early Universe, finding that, for the separation-to-core ratios we can achieve, the changing density of the network has little impact on the axion production efficiency.

  2. NEUTRONIC REACTOR CORE INSTRUMENT

    DOEpatents

    Mims, L.S.

    1961-08-22

    A multi-purpose instrument for measuring neutron flux, coolant flow rate, and coolant temperature in a nuclear reactor is described. The device consists essentially of a hollow thimble containing a heat conducting element protruding from the inner wall, the element containing on its innermost end an amount of fissionsble materinl to function as a heat source when subjected to neutron flux irradiation. Thermocouple type temperature sensing means are placed on the heat conducting element adjacent the fissionable material and at a point spaced therefrom, and at a point on the thimble which is in contact with the coolant fluid. The temperature differentials measured between the thermocouples are determinative of the neutron flux, coolant flow, and temperature being measured. The device may be utilized as a probe or may be incorporated in a reactor core. (AE C)

  3. HTTF Core Stress Analysis

    SciTech Connect

    Brian D. Hawkes; Richard Schultz

    2012-07-01

    In accordance with the need to determine whether cracking of the ceramic core disks which will be constructed and used in the High Temperature Test Facility (HTTF) for heatup and cooldown experiments, a set of calculation were performed using Abaqus to investigate the thermal stresses levels and likelihood for cracking. The calculations showed that using the material properties provided for the Greencast 94F ceramic, cracking is predicted to occur. However, this modeling does not predict the size or length of the actual cracks. It is quite likely that cracks will be narrow with rough walls which would impede the flow of coolant gases entering the cracks. Based on data recorded at Oregon State University using Greencast 94F samples that were heated and cooled at prescribed rates, it was concluded that the likelihood that the cracks would be detrimental to the experimental objectives is small.

  4. Growth outside the core.

    PubMed

    Zook, Chris; Allen, James

    2003-12-01

    Growth in an adjacent market is tougher than it looks; three-quarters of the time, the effort fails. But companies can change those odds dramatically. Results from a five-year study of corporate growth conducted by Bain & Company reveal that adjacency expansion succeeds only when built around strong core businesses that have the potential to become market leaders. And the best place to look for adjacency opportunities is inside a company's strongest customers. The study also found that the most successful companies were able to consistently, profitably outgrow their rivals by developing a formula for pushing out the boundaries of their core businesses in predictable, repeatable ways. Companies use their repeatability formulas to expand into any number of adjacencies. Some companies make repeated geographic moves, as Vodafone has done in expanding from one geographic market to another over the past 13 years, building revenues from $1 billion in 1990 to $48 billion in 2003. Others apply a superior business model to new segments. Dell, for example, has repeatedly adapted its direct-to-customer model to new customer segments and new product categories. In other cases, companies develop hybrid approaches. Nike executed a series of different types of adjacency moves: it expanded into adjacent customer segments, introduced new products, developed new distribution channels, and then moved into adjacent geographic markets. The successful repeaters in the study had two common characteristics. First, they were extraordinarily disciplined, applying rigorous screens before they made an adjacency move. This discipline paid off in the form of learning curve benefits, increased speed, and lower complexity. And second, in almost all cases, they developed their repeatable formulas by studying their customers and their customers' economics very, very carefully.

  5. GPM Core Observatory Launch Animation

    NASA Video Gallery

    This animation depicts the launch of the Global Precipitation Measurement (GPM) Core Observatory satellite from Tanegashima Space Center, Japan. The launch is currently scheduled for Feb. 27, 2014....

  6. Glass-clad semiconductor core optical fibers

    NASA Astrophysics Data System (ADS)

    Morris, Stephanie Lynn

    Glass-clad optical fibers comprising a crystalline semiconductor core 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 core fibers possess three performance-limiting characteristics that need to be addressed: (a) thermal expansion mismatches between crystalline core and glass cladding that lead to cracks, (b) the precipitation of oxide species in the core upon fiber cooling, which results from partial dissolution of the cladding glass by the core melt, 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 cores based on two main design criteria: (1) matching the thermal expansion coefficient between semiconductor core 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 melting 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

  7. Metrics for Success: Strategies for Enabling Core Facility Performance and Assessing Outcomes.

    PubMed

    Turpen, Paula B; Hockberger, Philip E; Meyn, Susan M; Nicklin, Connie; Tabarini, Diane; Auger, Julie A

    2016-04-01

    Core Facilities are key elements in the research portfolio of academic and private research institutions. Administrators overseeing core facilities (core administrators) require assessment tools for evaluating the need and effectiveness of these facilities at their institutions. This article discusses ways to promote best practices in core facilities as well as ways to evaluate their performance across 8 of the following categories: general management, research and technical staff, financial management, customer base and satisfaction, resource management, communications, institutional impact, and strategic planning. For each category, we provide lessons learned that we believe contribute to the effective and efficient overall management of core facilities. If done well, we believe that encouraging best practices and evaluating performance in core facilities will demonstrate and reinforce the importance of core facilities in the research and educational mission of institutions. It will also increase job satisfaction of those working in core facilities and improve the likelihood of sustainability of both facilities and personnel.

  8. Metrics for Success: Strategies for Enabling Core Facility Performance and Assessing Outcomes

    PubMed Central

    Hockberger, Philip E.; Meyn, Susan M.; Nicklin, Connie; Tabarini, Diane; Auger, Julie A.

    2016-01-01

    Core Facilities are key elements in the research portfolio of academic and private research institutions. Administrators overseeing core facilities (core administrators) require assessment tools for evaluating the need and effectiveness of these facilities at their institutions. This article discusses ways to promote best practices in core facilities as well as ways to evaluate their performance across 8 of the following categories: general management, research and technical staff, financial management, customer base and satisfaction, resource management, communications, institutional impact, and strategic planning. For each category, we provide lessons learned that we believe contribute to the effective and efficient overall management of core facilities. If done well, we believe that encouraging best practices and evaluating performance in core facilities will demonstrate and reinforce the importance of core facilities in the research and educational mission of institutions. It will also increase job satisfaction of those working in core facilities and improve the likelihood of sustainability of both facilities and personnel. PMID:26848284

  9. Phosphoethanolamine addition to the Heptose I of the Lipopolysaccharide modifies the inner core structure and has an impact on the binding of Polymyxin B to the Escherichia coli outer membrane.

    PubMed

    Salazar, Javier; Alarcón, Mackarenna; Huerta, Jaime; Navarro, Belén; Aguayo, Daniel

    2017-03-22

    Phosphoethanolamine (pEtN) decoration of E. coli Lipopolysaccharide (LPS) provides resistance to the antimicrobial Polymyxin B (PolB). While EptA and EptB enzymes catalyze the addition of pEtN to the Lipid A and Kdo (pEtN-Kdo-Lipid A), EptC catalyzes the pEtN addition to the Heptose I (pEtN-HeptI). In this study, we investigated the contribution of pEtN-HeptI to PolB resistance using eptA/eptB and eptC deficient E. coli K12 and its wild-type parent strains. These mutations were shown to decrease the antimicrobial activity of PolB on cells grown under pEtN-addition inducing conditions. Furthermore, the 1-N-phenylnapthylamine uptake assay revealed that in vivo PolB has a reduced OM-permeabilizing activity on the ΔeptA/eptB strain compared with the ΔeptC strain. In vitro, the changes in size and zeta potential of LPS-vesicles indicate that pEtN-HeptI reduce the PolB binding, but in a minor extent than pEtN-Kdo-Lipid A. Molecular dynamics analysis revealed the structural basis of the PolB resistance promoted by pEtN-HeptI, which generate a new hydrogen-bonding networks and a denser inner core region. Altogether, the experimental and theoretical assays shown herein indicate that pEtN-HeptI addition promote an LPS conformational rearrangement, that could act as a shield by hindering the accession of PolB to inner LPS-targets moieties.

  10. IN-CORE FUEL MANAGEMENT: PWR Core Calculations Using MCRAC

    NASA Astrophysics Data System (ADS)

    PetroviĆ, B. G.

    1991-01-01

    The following sections are included: * INTRODUCTION * IN-CORE FUEL MANAGEMENT CALCULATIONS * In-Core Fuel Management * Methodological Problems of In-Core Fuel Management * In-Core Fuel Management Analytical Tools * PENN STATE FUEL MANAGEMENT PACKAGE * Penn State Fuel Management Package (PFMP) * Assembly Data Description (ADD) * Linking PSU-LEOPARD and MCRAC: An Example * MULTICYCLE REACTOR ANALYSIS CODE (MCRAC) * Main Features and Options of MCRAC code * Core geometry * Diffusion equations * 1.5-group model * Multicycle neutronic analysis * Multicycle cost analysis * Criticality search * Power-dependent xenon feedback calculations * Control rod and burnable absorber simulation * Search for LP with flat BOC power distribution * Artificial ADD option * Variable dimensioning technique * RBI version of MCRAC code * Programming changes in PC version * Fuel interchange option * MCRAC Input/Output * General input description * Sample input * Sample output * EXPERIENCE WITH MCRAC CODE * CONCLUSIONS * REFERENCES

  11. Relativistic frozen core potential scheme with relaxation of core electrons

    NASA Astrophysics Data System (ADS)

    Nakajima, Yuya; Seino, Junji; Hayami, Masao; Nakai, Hiromi

    2016-10-01

    This letter proposes a relaxation scheme for core electrons based on the frozen core potential method at the infinite-order Douglas-Kroll-Hess level, called FCP-CR. The core electrons are self-consistently relaxed using frozen molecular valence potentials after the valence SCF calculation is performed. The efficiency of FCP-CR is confirmed by calculations of gold clusters. Furthermore, FCP-CR reproduces the results of the all-electron method for the energies of coinage metal dimers and the core ionization energies and core level shifts of vinyl acetate and three tungsten complexes at the Hartree-Fock and/or symmetry-adapted cluster configuration interaction levels.

  12. Business Planning Core Facilities

    PubMed Central

    Itzkowitz, G.N.

    2014-01-01

    Thoughtful business planning is pivotal to the success of any business/operational venture. When planned in a thoughtful and detailed manner there are very few operational or financial surprises for an institution or facility (service center) to contend with. At Stony Brook Medicine we include SWOT analysis and a detailed Market Analysis as part of the process. This is bolstered by an initiative to ensure institutional policies are met so that facilities remain in compliance throughout their lifecycle. As we operate 14 facilities we have had the opportunity to become creative in our approach to coordinate activities, virtualize services, integrate new software business-to-business partners, and finally coordinate plans for phased consolidation instead of outright termination of services when required. As the Associate Dean for Scientific Operations and Research Facilities, the shared research facilities (cores) of the Medical School are in my direct line of sight. We understand their value to the meeting our overall research mission. We have found that an active process of monitoring to predict trouble as much as possible is the best approach for facilities. Some case analysis of this type of interaction will be presented as well.

  13. Adult educators' core competences

    NASA Astrophysics Data System (ADS)

    Wahlgren, Bjarne

    2016-06-01

    Which competences do professional adult educators need? This research note discusses the topic from a comparative perspective, finding that adult educators' required competences are wide-ranging, heterogeneous and complex. They are subject to context in terms of national and cultural environment as well as the kind of adult education concerned (e.g. basic education, work-related education etc.). However, it seems that it is possible to identify certain competence requirements which transcend national, cultural and functional boundaries. This research note summarises these common or "core" requirements, organising them into four thematic subcategories: (1) communicating subject knowledge; (2) taking students' prior learning into account; (3) supporting a learning environment; and (4) the adult educator's reflection on his or her own performance. At the end of his analysis of different competence profiles, the author notes that adult educators' ability to train adult learners in a way which then enables them to apply and use what they have learned in practice (thus performing knowledge transfer) still seems to be overlooked.

  14. Variable depth core sampler

    SciTech Connect

    Bourgeois, P.M.; Reger, R.J.

    1994-12-31

    This invention relates to a sampling means, more particularly to a device to sample hard surfaces at varying depths. Often it is desirable to take samples of a hard surface wherein the samples are of the same diameter but of varying depths. Current practice requires that a full top-to-bottom sample of the material be taken, using a hole saw, and boring a hole from one end of the material to the other. The sample thus taken is removed from the hole saw and the middle of said sample is then subjected to further investigation. This paper describes a variable depth core sampler comprimising a circular hole saw member, having longitudinal sections that collapse to form a point and capture a sample, and a second saw member residing inside the first hole saw member to support the longitudinal sections of the first member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside the the first hole saw member.

  15. Core-to-core uniformity improvement in multi-core fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Lindley, Emma; Min, Seong-Sik; Leon-Saval, Sergio; Cvetojevic, Nick; Jovanovic, Nemanja; Bland-Hawthorn, Joss; Lawrence, Jon; Gris-Sanchez, Itandehui; Birks, Tim; Haynes, Roger; Haynes, Dionne

    2014-07-01

    Multi-core fiber Bragg gratings (MCFBGs) will be a valuable tool not only in communications but also various astronomical, sensing and industry applications. In this paper we address some of the technical challenges of fabricating effective multi-core gratings by simulating improvements to the writing method. These methods allow a system designed for inscribing single-core fibers to cope with MCFBG fabrication with only minor, passive changes to the writing process. Using a capillary tube that was polished on one side, the field entering the fiber was flattened which improved the coverage and uniformity of all cores.

  16. Thermochemical Evolution of Earth's Core with Magnesium Precipitation

    NASA Astrophysics Data System (ADS)

    O'Rourke, J. G.; Stevenson, D. J.

    2014-12-01

    Vigorous convection within Earth's outer core drives a dynamo that has sustained a global magnetic field for at least 3.5 Gyr. Traditionally, people invoke three energy sources for the dynamo: thermal convection from cooling and freezing, compositional convection from light elements expelled by the growing inner core, and, perhaps, radiogenic heating from potassium-40. New theoretical and experimental work, however, indicates that the thermal and electrical conductivities of the outer core may be as much as three times higher than previously assumed. The implied increase in the adiabatic heat flux casts doubt on the ability of the usual mechanisms to explain the dynamo's longevity. Here, we present a quantitative model of the crystallization of magnesium-bearing minerals from the cooling core—a plausible candidate for the missing power source. Recent diamond-anvil cell experiments suggest that magnesium can partition into core material if thermodynamic equilibrium is achieved at high temperatures (>5000 K). We develop a model for core/mantle differentiation in which most of the core forms from material equilibrated at the base of a magma ocean as Earth slowly grows, but a small portion (~10%) equilibrated at extreme conditions in the aftermath of a giant impact. We calculate the posterior probability distribution for the original concentrations of magnesium and other light elements (chiefly oxygen and silicon) in the core, constrained by partitioning experiments and the observed depletion of siderophile elements in Earth's mantle. We then simulate the thermochemical evolution of cores with plausible compositions and thermal structures from the end of accretion to the present, focusing on the crystallization of a few percent of the initial core as ferropericlase and bridgmanite. Finally, we compute the associated energy release and verify that our final core compositions are consistent with the available seismological data.

  17. Powering Earth's dynamo with magnesium precipitation from the core.

    PubMed

    O'Rourke, Joseph G; Stevenson, David J

    2016-01-21

    Earth's global magnetic field arises from vigorous convection within the liquid outer core. Palaeomagnetic evidence reveals that the geodynamo has operated for at least 3.4 billion years, which places constraints on Earth's formation and evolution. Available power sources in standard models include compositional convection (driven by the solidifying inner core's expulsion of light elements), thermal convection (from slow cooling), and perhaps heat from the decay of radioactive isotopes. However, recent first-principles calculations and diamond-anvil cell experiments indicate that the thermal conductivity of iron is two or three times larger than typically assumed in these models. This presents a problem: a large increase in the conductive heat flux along the adiabat (due to the higher conductivity of iron) implies that the inner core is young (less than one billion years old), but thermal convection and radiogenic heating alone may not have been able to sustain the geodynamo during earlier epochs. Here we show that the precipitation of magnesium-bearing minerals from the core could have served as an alternative power source. Equilibration at high temperatures in the aftermath of giant impacts allows a small amount of magnesium (one or two weight per cent) to partition into the core while still producing the observed abundances of siderophile elements in the mantle and avoiding an excess of silicon and oxygen in the core. The transport of magnesium as oxide or silicate from the cooling core to underneath the mantle is an order of magnitude more efficient per unit mass as a source of buoyancy than inner-core growth. We therefore conclude that Earth's dynamo would survive throughout geologic time (from at least 3.4 billion years ago to the present) even if core radiogenic heating were minimal and core cooling were slow.

  18. COVERING A CORE BY EXTRUSION

    DOEpatents

    Karnie, A.J.

    1963-07-16

    A method of covering a cylindrical fuel core with a cladding metal ms described. The metal is forced between dies around the core from both ends in two opposing skirts, and as these meet the ends turn outward into an annular recess in the dics. By cutting off the raised portion formed by the recess, oxide impurities are eliminated. (AEC)

  19. Common Core: Victory Is Yours!

    ERIC Educational Resources Information Center

    Fink, Jennifer L. W.

    2012-01-01

    In this article, the author discusses how to implement the Common Core State Standards in the classroom. She presents examples and activities that will leave teachers feeling "rosy" about tackling the new standards. She breaks down important benchmarks and shows how other teachers are doing the Core--and loving it!

  20. Complicated Politics to the Core

    ERIC Educational Resources Information Center

    McGuinn, Patrick

    2015-01-01

    People dislike the Common Core for several different reasons, and so it is important to disaggregate the sources of opposition and to assess and then to dispel some of the myths that have built up around it. It also is important to understand the unusual political alliances that have emerged in opposition to Common Core implementation and how they…

  1. Differential regulation and impact of fucosyltransferase VII and core 2 β1,6-N-acetyl-glycosaminyltransferase for generation of E-selectin and P-selectin ligands in murine CD4+ T cells.

    PubMed

    Schroeter, Micha F; Ratsch, Boris A; Lehmann, Jeanette; Baumgrass, Ria; Hamann, Alf; Syrbe, Uta

    2012-12-01

    Ligands for E-selectin and P-selectin (E-lig and P-lig) are induced on CD4+ T cells upon differentiation into effector T cells. Glycosyltransferases, especially α 1,3-fucosyltransferase VII (FucT-VII) and core 2 β1,6-N-acetyl-glycosaminyltransferase I (C2GlcNAcT-I), are critical for their synthesis. We here analysed the signals that control the expression of E-lig, P-lig and mRNA coding for FucT-VII and C2GlcNAcT-I. In line with previous reports, we found that P-lig expression correlates with the regulation of C2GlcNAcT-I, whereas E-lig expression can occur at low levels of C2GlcNAcT-I mRNA but requires high FucT-VII mRNA expression. Interestingly, the two enzymes are regulated by different signals. Activation-induced C2GlcNAcT-I up-regulation under permissive (T helper type 1) conditions was strongly reduced by cyclosporin A (CsA), suggesting the involvement of T-cell receptor-dependent, calcineurin/NFAT-dependent signals in combination with interleukin-12 (IL-12) -mediated signals in the regulation of C2GlcNAcT-I. In contrast, expression of FucT-VII mRNA was not significantly inhibited by CsA. Interleukin-4 inhibited the expression of FucT-VII but IL-2 and IL-7 were found to support induction of FucT-VII and E-lig. E-selectin, P-selectin and their ligands initially appeared to have rather overlapping functions. These findings however, unravel striking differences in the regulation of E-lig and P-lig expression, dictated by the dominance of FucT-VII and C2GlcNAcT-I, respectively, and their dependency on signals from either promiscuous or homeostatic cytokines (FucT-VII) or a strong T-cell receptor signal in combination with inflammatory cytokines in case of C2GlcNAcT-I.

  2. The Common Core: A Disaster for Libraries, a Disaster for Language Arts, a Disaster for American Education

    ERIC Educational Resources Information Center

    Krashen, Stephen

    2014-01-01

    This author contends that there never has been a need for the Common Core State Standards (CCSS), and there is no evidence that it will do students any good. The Common Core ignores the real problem in American education: poverty. The Common Core movement will be a disaster for libraries and will have a negative impact on nearly every aspect of…

  3. Data interchange across cores of multi-core optical fibers

    NASA Astrophysics Data System (ADS)

    Awad, Ehab S.

    2015-12-01

    A novel device for data interchange among space-division multiplexed cores inside MCF is demonstrated using numerical simulations. The device allows complete exchange of all WDM data channels between MCF cores in propagation direction whether the channels have the same or different sets of wavelengths. This is crucial in future MCF optical networks where in-fiber data interchange over space-division multiplexed cores can allow for a simple and fast data swapping among cores without a need for space-division demultiplexing to single-mode single-core fibers. The data core-interchange (DCI) device consists of a graded refractive-index rectangular waveguide enclosing the two interchanged cores in addition to the cladding region in between them. Both finite-difference-time-domain (FDTD) and eigenmode expansion (EME) simulations are performed to verify the device operation and characterize its performance. The simulations demonstrate that the DCI has a very short-length with polarization independent operation, and high performance over the broadband wavelength range S, C, L, and U bands. Moreover, the device shows a high coupling-factor of -0.13 dB with small cross-talk, back-reflection, and return-loss of -26.3, -46.1, and -48.8 dB, respectively.

  4. High thermal stability of core-shell structures dominated by negative interface energy.

    PubMed

    Zhu, Yong-Fu; Zhao, Ning; Jin, Bo; Zhao, Ming; Jiang, Qing

    2017-03-29

    Nanoscale core/shell structures are of interest in catalysis due to their superior catalytic properties. Here we investigated the thermal stability of the coherent core-shell structures in a thermodynamic way by considering the impact from the core with the bulk melting point Tm(∞) lower or higher than the shell. When a low-Tm(∞) core is adopted, core-shell melting induced by the melting depression of the core does not occur upon heating because of the superheating, although the melting depression of the core can be triggered ultimately by the preferential melting of the high-Tm(∞) shell for small cores. The superheating of the core is contributed by the negative solid-solid interface energy, while the depression is originated from the positive solid-liquid interface energy. Owing to the presence of the negative interface energy, moreover, the low-Tm(∞)-core structure possesses a low difference in thermal expansion between the core and the shell, high activation energy of outward atomic diffusion from the core to shell, and low heat capacity. This result is beneficial for the core-shell structure design for its application in catalysis.

  5. Crystallization in Earth's Core after High-Temperature Core Formation

    NASA Astrophysics Data System (ADS)

    Hirose, K.; Morard, G.; Hernlund, J. W.; Helffrich, G. R.; Ozawa, H.

    2015-12-01

    Recent core formation models based on the metal-silicate partitioning of siderophile elements suggest that the Earth's core was formed by metal segregation at high pressure and high temperature in a deep magma ocean. It is also thought that the simultaneous solubility of silicon and oxygen in liquid iron are strongly enhanced at high pressure and high temperature, such that at the end of accretion the core was rich in both silicon and oxygen. Here we performed crystallization experiments on the Fe-Si binary and Fe-Si-O ternary systems up to core pressure in a laser-heated diamond-anvil cell. The starting material for the latter was a homogeneous mixture of fine-grain Fe-Si and SiO2 (<1 µm). We prepared cross sections of samples recovered from the DAC using a focused ion beam (FIB) and subsequently performed textural and chemical characterization with field-emission-type electron microprobe (FE-EPMA). Quenched liquid alloy was found at the hottest part coexisting with a solid phase (liquidus phase) at the periphery. These results combined with literature data on the melting phase relations in the Fe-FeO binary system demonstrate that the liquidus field of SiO2 is very wide at the Fe-rich portion of the Fe-Si-O ternary system at the core pressure range. It indicates that the original Fe-Si-O core liquid should have crystallized a large amount SiO2 until it lost either silicon or oxygen. The recent finding of high thermal conductivity of the core suggests that core thermal convection is difficult to sustain without extreme degrees of secular cooling. However, even for modest degrees of joint Si-O incorporation into the early core, the buoyancy released by crystallization of SiO2 is sufficient to overcome thermal stratification and sustain the geodynamo.

  6. Evaluating the core microbiota in complex communities: A systematic investigation.

    PubMed

    Astudillo-García, Carmen; Bell, James J; Webster, Nicole S; Glasl, Bettina; Jompa, Jamaluddin; Montoya, Jose M; Taylor, Michael W

    2017-04-01

    The study of complex microbial communities poses unique conceptual and analytical challenges, with microbial species potentially numbering in the thousands. With transient or allochthonous microorganisms often adding to this complexity, a 'core' microbiota approach, focusing only on the stable and permanent members of the community, is becoming increasingly popular. Given the various ways of defining a core microbiota, it is prudent to examine whether the definition of the core impacts upon the results obtained. Here we used complex marine sponge microbiotas and undertook a systematic evaluation of the degree to which different factors used to define the core influenced the conclusions. Significant differences in alpha- and beta-diversity were detected using some but not all core definitions. However, findings related to host specificity and environmental quality were largely insensitive to major changes in the core microbiota definition. Furthermore, none of the applied definitions altered our perception of the ecological networks summarising interactions among bacteria within the sponges. These results suggest that, while care should still be taken in interpretation, the core microbiota approach is surprisingly robust, at least for comparing microbiotas of closely related samples.

  7. Implications of Common Core State Standards on the Social Studies

    ERIC Educational Resources Information Center

    Kenna, Joshua L.; Russell, William B., III.

    2014-01-01

    Social studies teachers have often been on the outside looking in during much of the era billed as the standards-based educational reform (SBER), but with the adoption and implementation of the Common Core State Standards (CCSS), social studies teachers seem to have been invited back inside. Yet, how will the standards impact social studies…

  8. Developing and Assessing Educator Beliefs about the Common Core

    ERIC Educational Resources Information Center

    Liou, Yi-Hwa; Moolenaar, Nienke M.; Daly, Alan J.

    2016-01-01

    The Common Core State Standards (CCSS) potentially shifts the way US schools approach teaching and learning. Research suggests that it is important to understand how educators view the CCSS and how they believe the CCSS may impact their practice. We developed and tested an instrument to investigate educator beliefs about the implementation of…

  9. Core Sciences in First-Year Learning Communities

    ERIC Educational Resources Information Center

    Richardson, Nicholas; Tooker, Patricia A.; Eshleman, Amy

    2014-01-01

    Learning communities (LCs) offer high-impact practices of active learning and practical application, but such practices demand devoted class time and room for reflection. Core science courses that serve as prerequisites for more advanced courses have specific and fixed content that offers no space in which to incorporate the ideals of LCs. Wagner…

  10. Technology and Engineering Education and the Common Core Standards

    ERIC Educational Resources Information Center

    Rust, Terrie

    2012-01-01

    The nearly unanimous state acceptance of the Common Core State Standards (CCSS) in mathematics and English Language Arts (ELA) jolted many teachers out of their complacency. How was this major change going to impact their teaching and their curriculum? What changes would be made in student assessments and teacher accountability? The good news is…

  11. DOE GIS core team - a best practice

    SciTech Connect

    Bollinger, J.; Bhaduri, Budhendra; Bleakly, D. R.; Brady-Sabeff, Liz; Guber, Al; Guziel, K. A.; Hargrove, Susan; Lee, J.; Lee, R.; Mickus, Kurt; Morehouse, David; Moore, K.; Ramsdell, Amy; Rich, P. M.

    2004-01-01

    Large government organizations such as the Department of Energy (DOE) are challenged with identifying and implementing best geospatial information management practices to ensure that operational needs are met and government objectives are achieved. Geographic Information System (GIS) professionals, complex wide within the Department, conduct spatial information management practices on a daily basis to complete a wide variety of science and engineering tasks. The DOE Office of the CIO recognized the wealth of geospatial information management knowledge within the DOE complex and formed the DOE GIS Core Team in 2001 as a result. The team is comprised of GIS experts-representing all major DOE labs, site facilities, and programs-who volunteer their time to address issues impacting the entire complex. These include the President's management agenda (with emphasis on the Geospatial One-Stop), homeland security, emergency response, site management, software and geospatial data licensing, and federal, national, and international standards governing the creation and dissemination of geospatial data. The strength of the DOE GIS Core Team is the wide diversity of GIS and scientific expertise represented on the team, which allows it to provide the DOE CIO's office with sound guidance on complex wide issues from a GIS practitioner's perspective. The Core Team's mission is 'to foster technical excellence and communication, to identify and advocate best business practices, and to provide sound recommendations on policy and standards.' As a first step toward identifying best practices the feam conducted a survey of all known GIS assets across the DOE complex. The survey identified each site's GIS expertise, operating systems architecture and software applications, major project areas supported, and a number of other metrics important to the operation of a GIS organization. Results of the survey will be discussed, along with the mission of the Core Team. A broad overview of best

  12. Radiation Effects: Core Project

    NASA Technical Reports Server (NTRS)

    Dicello, John F.

    1999-01-01

    The risks to personnel in space from the naturally occurring radiations are generally considered to be one of the most serious limitations to human space missions, as noted in two recent reports of the National Research Council/National Academy of Sciences. The Core Project of the Radiation Effects Team for the National Space Biomedical Research Institute is the consequences of radiations in space in order to develop countermeasure, both physical and pharmaceutical, to reduce the risks of cancer and other diseases associated with such exposures. During interplanetary missions, personnel in space will be exposed to galactic cosmic rays, including high-energy protons and energetic ions with atomic masses of iron or higher. In addition, solar events will produce radiation fields of high intensity for short but irregular durations. The level of intensity of these radiations is considerably higher than that on Earth's surface, and the biological risks to astronauts is consequently increased, including increased risks of carcinogenesis and other diseases. This group is examining the risk of cancers resulting from low-dose, low-dose rate exposures of model systems to photons, protons, and iron by using ground-based accelerators which are capable of producing beams of protons, iron, and other heavy ions at energies comparable to those encountered in space. They have begun the first series of experiments using a 1-GeV iron beam at the Brookhaven National Laboratory and 250-MeV protons at Loma Linda University Medical Center's proton synchrotron facility. As part of these studies, this group will be investigating the potential for the pharmaceutical, Tamoxifen, to reduce the risk of breast cancer in astronauts exposed to the level of doses and particle types expected in space. Theoretical studies are being carried out in a collaboration between scientists at NASA's Johnson Space Center and Johns Hopkins University in parallel with the experimental program have provided

  13. Dynamics of the core, geodynamo

    NASA Astrophysics Data System (ADS)

    Roberts, Paul H.

    1995-07-01

    "The mechanism for generating the geomagnetic field remains one of the central unsolved problems in geoscience." So states the report on the National Geomagnetic Initiative (NGI) prepared by the U.S. Geodynamics Committee, et al [1993], with advice from the NGI Workshop held in Washington D.C. in March 1992. All analyses of the geomagnetic data point to the core as containing the source of the field and "The basic premise that virtually everyone accepts is that the Earth's magnetism is created by a self-sustaining dynamo driven by fluid motions in Earth's core" (NGI, p.135). Dynamical questions at once arise, such as "What is the energy source driving those motions?" Jacobs [1953] proposed that the solid inner core (SIC) is the result of the freezing of the fluid outer core (FOC). Verhoogen [1961] noticed that the release of latent heat at the inner core boundary (ICB) during freezing would help drive thermal convection in the FOC, and Braginsky [1963] pointed out that the release of the light alloying elements during fractionation at the ICB would provide compositional buoyancy. These two sources suffice to supply the geodynamo with energy throughout geological time, even in the absence of dissolved radioactivity in the core [Braginsky and Roberts, 1994a; Kuang et al, 1994]. Stevenson [1991] argues that potential differences on the core-mantle boundary (CMB) of electrochemical origin may be partially responsible for the geomagnetic field.

  14. Simplified cut core inductor design

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1974-01-01

    Although filter inductor designers have routinely tended to specify molypermalloy powder cores for use in high frequency power converters and pulse-width modulated switching regulators, there are sigificant advantages in specifying C cores and cut toroids fabricated from grain oriented silicon steels which should not be overlooked. Such steel cores can develop flux densities of 1.6 tesla, with useful linearity to 1.2 tesla, whereas molypermalloy cores carrying d.c. current have useful flux density capabilities only to about 0.3 tesla. The use of silicon steel cores thus makes it possible to design more compact cores, and therefore inductors of reduced volume, or conversely to provide greater load capacity in inductors of a given volume. Information is available which makes it possible to obtain quick and close approximations of significant parameters such as size, weight and temperature rise for silicon steel cores for breadboarding. Graphs, nomographs and tables are presented for this purpose, but more complete mathematical derivations of some of the important parameters are also included for a more rigorous treatment.

  15. Core physics analysis of 100% MOX Core in IRIS

    SciTech Connect

    Franceschini, F.; Petrovic, B.

    2006-07-01

    International Reactor Innovative and Secure (IRIS) is an advanced small-to-medium-size (1000 MWt) Pressurized Water Reactor (PWR), targeting deployment around 2015. Its reference core design is based on the current Westinghouse UO{sub 2} fuel with less than 5% {sup 235}U, and the analysis has been previously completed confirming good performance. The full MOX fuel core is currently under evaluation as one of the alternatives for the second wave of IRIS reactors. A full 3-D neutronic analysis has been performed to examine main core performance parameters, such as critical boron concentration, peaking factors, discharge burnup, etc. The enhanced moderation of the IRIS fuel lattice facilitates MOX core design, and all the obtained results are within the requirements, confirming viability of this option from the reactor physics standpoint. (authors)

  16. Core Exercises: Why You Should Strengthen Your Core Muscles

    MedlinePlus

    ... Read on to find out why. Core exercises train the muscles in your pelvis, lower back, hips ... manner that involves maintaining a stable trunk can train and strengthen several of your muscles, including your ...

  17. Calculation Technique for Kinematic Characteristics of Penetration of Combined Striker with Oblong Core Part Considering Possible Destruction of the Latter

    NASA Astrophysics Data System (ADS)

    Antsiferova, E. V.; Bogdanov, V. V.; Derebenko, E. V.; Lagutina, A. V.; Khmelnikov, E. A.

    2006-08-01

    The up-to-date development of the armored vehicles conditions complication of armor constructions and increased slope of shell armored plates. Combined strikers (C/S) can be used to destroy armored vehicles. We can increase total weight of the core part to increase the striker's power. However, the increase of core part diameter is limited by body dimensions. Thus, we can increase core part weight by increasing its length. Because of C/S interaction with the barriers at large deviation angles, C/S's mechanical trajectory sparks in the barrier. This results in bending stress which occurs in the core part. Because of large deviation angles, the impact of the side surface of oblong core part against the cavity edge occurs. This increases the probability of core part destruction. The calculation technique for oblong core part penetration into different types of barriers is presented. The large number of factors can be calculated using this technique. It is assumed that the core part is destroyed when the tail part impacts against the cavity in the section where specific impact energy exceeds the critical value. Impact elasticity and destruction at bending stress were selected to be destruction criteria. The following core part destruction scenarios were investigated and calculated: (i) core head part is slightly destroyed but tail part of cylindrical shape penetrates deeper; (ii) core tail part is slightly destroyed but head part penetrates deeper, mass loss is taken into account; and (iii) after the impact, the core part is splitted up into two parts, then both of them penetrate into the barrier, one part is of ogival shape, the other is of cylindrical one. This calculation technique was applied to computational program, then critical angles at which core part side surface is still in contact with cavity surface, and the angles at which core part destruction occurs were calculated. Depths of core part penetration for different destruction scenarios were calculated.

  18. Uranium droplet core nuclear rocket

    NASA Technical Reports Server (NTRS)

    Anghaie, Samim

    1991-01-01

    Uranium droplet nuclear rocket is conceptually designed to utilize the broad temperature range ofthe liquid phase of metallic uranium in droplet configuration which maximizes the energy transfer area per unit fuel volume. In a baseline system dissociated hydrogen at 100 bar is heated to 6000 K, providing 2000 second of Isp. Fission fragments and intense radian field enhance the dissociation of molecular hydrogen beyond the equilibrium thermodynamic level. Uranium droplets in the core are confined and separated by an axisymmetric vortex flow generated by high velocity tangential injection of hydrogen in the mid-core regions. Droplet uranium flow to the core is controlled and adjusted by a twin flow nozzle injection system.

  19. Surface-core fiber gratings

    NASA Astrophysics Data System (ADS)

    Osório, Jonas H.; Oliveira, Ricardo; Mosquera, L.; Franco, Marcos A. R.; Heidarialamdarloo, Jamshid; Bilro, Lúcia; Nogueira, Rogério N.; Cordeiro, Cristiano M. B.

    2015-09-01

    In this paper, we report, to our knowledge, the first demonstration of the induction of long-period and Bragg gratings on surface-core optical fibers. Surface-core fibers described herein were fabricated from commercial silica tubes and germanium-doped silica rods by employing a very simple procedure. Being the core on the fiber surface, it can be sensitive to refractive index variations in the environment in which the fiber is immersed. Thus, results concerning the sensitivity of these gratings to environmental refractive index variations are presented. Besides, simulation data are presented for comparison to the experimental behavior and for projecting future steps in this research.

  20. Characterizing Facesheet/Core Disbonding in Honeycomb Core Sandwich Structure

    NASA Technical Reports Server (NTRS)

    Rinker, Martin; Ratcliffe, James G.; Adams, Daniel O.; Krueger, Ronald

    2013-01-01

    Results are presented from an experimental investigation into facesheet core disbonding in carbon fiber reinforced plastic/Nomex honeycomb sandwich structures using a Single Cantilever Beam test. Specimens with three, six and twelve-ply facesheets were tested. Specimens with different honeycomb cores consisting of four different cell sizes were also tested, in addition to specimens with three different widths. Three different data reduction methods were employed for computing apparent fracture toughness values from the test data, namely an area method, a compliance calibration technique and a modified beam theory method. The compliance calibration and modified beam theory approaches yielded comparable apparent fracture toughness values, which were generally lower than those computed using the area method. Disbonding in the three-ply facesheet specimens took place at the facesheet/core interface and yielded the lowest apparent fracture toughness values. Disbonding in the six and twelve-ply facesheet specimens took place within the core, near to the facesheet/core interface. Specimen width was not found to have a significant effect on apparent fracture toughness. The amount of scatter in the apparent fracture toughness data was found to increase with honeycomb core cell size.

  1. Compression Behavior of Fluted-Core Composite Panels

    NASA Technical Reports Server (NTRS)

    Schultz, Marc R.; Oremont, Leonard; Guzman, J. Carlos; McCarville, Douglas; Rose, Cheryl A.; Hilburger, Mark W.

    2011-01-01

    In recent years, fiber-reinforced composites have become more accepted for aerospace applications. Specifically, during NASA s recent efforts to develop new launch vehicles, composite materials were considered and baselined for a number of structures. Because of mass and stiffness requirements, sandwich composites are often selected for many applications. However, there are a number of manufacturing and in-service concerns associated with traditional honeycomb-core sandwich composites that in certain instances may be alleviated through the use of other core materials or construction methods. Fluted-core, which consists of integral angled web members with structural radius fillers spaced between laminate face sheets, is one such construction alternative and is considered herein. Two different fluted-core designs were considered: a subscale design and a full-scale design sized for a heavy-lift-launch-vehicle interstage. In particular, axial compression of fluted-core composites was evaluated with experiments and finite-element analyses (FEA); axial compression is the primary loading condition in dry launch-vehicle barrel sections. Detailed finite-element models were developed to represent all components of the fluted-core construction, and geometrically nonlinear analyses were conducted to predict both buckling and material failures. Good agreement was obtained between test data and analyses, for both local buckling and ultimate material failure. Though the local buckling events are not catastrophic, the resulting deformations contribute to material failures. Consequently, an important observation is that the material failure loads and modes would not be captured by either linear analyses or nonlinear smeared-shell analyses. Compression-after-impact (CAI) performance of fluted core composites was also investigated by experimentally testing samples impacted with 6 ft.-lb. impact energies. It was found that such impacts reduced the ultimate load carrying capability by

  2. Assessing Core Competencies

    NASA Astrophysics Data System (ADS)

    Narayanan, M.

    2004-12-01

    Catherine Palomba and Trudy Banta offer the following definition of assessment, adapted from one provided by Marches in 1987. Assessment in the systematic collection, review, and use of information about educational programs undertaken for the purpose of improving student learning and development. (Palomba and Banta 1999). It is widely recognized that sophisticated computing technologies are becoming a key element in today's classroom instructional techniques. Regardless, the Professor must be held responsible for creating an instructional environment in which the technology actually supplements learning outcomes of the students. Almost all academic disciplines have found a niche for computer-based instruction in their respective professional domain. In many cases, it is viewed as an essential and integral part of the educational process. Educational institutions are committing substantial resources to the establishment of dedicated technology-based laboratories, so that they will be able to accommodate and fulfill students' desire to master certain of these specific skills. This type of technology-based instruction may raise some fundamental questions about the core competencies of the student learner. Some of the most important questions are : 1. Is the utilization of these fast high-powered computers and user-friendly software programs creating a totally non-challenging instructional environment for the student learner ? 2. Can technology itself all too easily overshadow the learning outcomes intended ? 3. Are the educational institutions simply training students how to use technology rather than educating them in the appropriate field ? 4. Are we still teaching content-driven courses and analysis oriented subject matter ? 5. Are these sophisticated modern era technologies contributing to a decline in the Critical Thinking Capabilities of the 21st century technology-savvy students ? The author tries to focus on technology as a tool and not on the technology

  3. Common Core State Standards in 2014: Districts' Perceptions, Progress, and Challenges

    ERIC Educational Resources Information Center

    Rentner, Diane Stark; Kober, Nancy

    2014-01-01

    This report, based on a survey of a nationally representative sample of school districts in Common Core-adopting states, examines school districts' efforts to implement the Common Core State Standards (CCSS). The report addresses district leaders' views on the rigor of the CCSS and their impact on learning and instruction, progress on and…

  4. The ADNI PET Core: 2015

    PubMed Central

    Jagust, William J.; Landau, Susan M.; Koeppe, Robert A.; Reiman, Eric M.; Chen, Kewei; Mathis, Chester A.; Price, Julie C.; Foster, Norman L.; Wang, Angela Y.

    2015-01-01

    INTRODUCTION This paper reviews the work done in the ADNI PET core over the past 5 years, largely concerning techniques, methods, and results related to amyloid imaging in ADNI. METHODS The PET Core has utilized [18F]florbetapir routinely on ADNI participants, with over 1600 scans available for download. Four different laboratories are involved in data analysis, and have examined factors such as longitudinal florbetapir analysis, use of FDG-PET in clinical trials, and relationships between different biomarkers and cognition. RESULTS Converging evidence from the PET Core has indicated that cross-sectional and longitudinal florbetapir analyses require different reference regions. Studies have also examined the relationship between florbetapir data obtained immediately after injection, which reflects perfusion, and FDG-PET results. Finally, standardization has included the translation of florbetapir PET data to a centiloid scale. CONCLUSION The PET Core has demonstrated a variety of methods for standardization of biomarkers such as florbetapir PET in a multicenter setting. PMID:26194311

  5. Convection, nucleosynthesis, and core collapse

    NASA Technical Reports Server (NTRS)

    Bazan, Grant; Arnett, David

    1994-01-01

    We use a piecewise parabolic method hydrodynamics code (PROMETHEUS) to study convective burning in two dimensions in an oxygen shell prior to core collapse. Significant mixing beyond convective boundaries determined by mixing-length theory brings fuel (C-12) into the convective regon, causing hot spots of nuclear burning. Plumes dominate the velocity structure. Finite perturbations arise in a region in which O-16 will be explosively burned to Ni-56 when the star explodes; the resulting instabilities and mixing are likely to distribute Ni-56 throughout the supernova envelope. Inhomogeneities in Y(sub e) may be large enough to affect core collapse and will affect explosive nucleosynthesis. The nature of convective burning is dramatically different from that assumed in one-dimensional simulations; quantitative estimates of nucleosynthetic yields, core masses, and the approach to core collapse will be affected.

  6. Simplifier cut core inductor design

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1976-01-01

    Advantages of specifying C cores and cut toroids fabricated from grain oriented silicon steels for use in high frequency power converters and pulse width modulated switching regulators are discussed. A method for rating cores assigns to each core a number which is the product of its window and core cross section area, called 'Area Product A sub p.' A correlation between the A sub p numbers and current density for a given temperature rise was developed. Also, straight line relationships were developed for A sub p and volume, A sub p and surface area, and A sub p and weight. These relationships can be used to simplify and standardize the process of inductor design. They also make it possible to design inductors of small bulk and volume or to optimize efficiency.

  7. Core Recursive Hierarchical Image Segmentation

    NASA Technical Reports Server (NTRS)

    Tilton, James

    2011-01-01

    The Recursive Hierarchical Image Segmentation (RHSEG) software has been repackaged to provide a version of the RHSEG software that is not subject to patent restrictions and that can be released to the general public through NASA GSFC's Open Source release process. Like the Core HSEG Software Package, this Core RHSEG Software Package also includes a visualization program called HSEGViewer along with a utility program HSEGReader. It also includes an additional utility program called HSEGExtract. The unique feature of the Core RHSEG package is that it is a repackaging of the RHSEG technology designed to specifically avoid the inclusion of the certain software technology. Unlike the Core HSEG package, it includes the recursive portions of the technology, but does not include processing window artifact elimination technology.

  8. Bidirectional Lipid Droplet Velocities Are Controlled by Differential Binding Strengths of HCV Core DII Protein

    PubMed Central

    Lyn, Rodney K.; Hope, Graham; Sherratt, Allison R.; McLauchlan, John; Pezacki, John Paul

    2013-01-01

    Host cell lipid droplets (LD) are essential in the hepatitis C virus (HCV) life cycle and are targeted by the viral capsid core protein. Core-coated LDs accumulate in the perinuclear region and facilitate viral particle assembly, but it is unclear how mobility of these LDs is directed by core. Herein we used two-photon fluorescence, differential interference contrast imaging, and coherent anti-Stokes Raman scattering microscopies, to reveal novel core-mediated changes to LD dynamics. Expression of core protein’s lipid binding domain II (DII-core) induced slower LD speeds, but did not affect directionality of movement on microtubules. Modulating the LD binding strength of DII-core further impacted LD mobility, revealing the temporal effects of LD-bound DII-core. These results for DII-core coated LDs support a model for core-mediated LD localization that involves core slowing down the rate of movement of LDs until localization at the perinuclear region is accomplished where LD movement ceases. The guided localization of LDs by HCV core protein not only is essential to the viral life cycle but also poses an interesting target for the development of antiviral strategies against HCV. PMID:24223760

  9. Viscosity of the earth's core.

    NASA Technical Reports Server (NTRS)

    Gans, R. F.

    1972-01-01

    Calculation of the viscosity of the core at the boundary of the inner and outer core. It is assumed that this boundary is a melting transition and the viscosity limits of the Andrade (1934,1952) hypothesis (3.7 to 18.5 cp) are adopted. The corresponding kinematic viscosities are such that the precessional system explored by Malkus (1968) would be unstable. Whether it would be sufficiently unstable to overcome a severely subadiabatic temperature gradient cannot be determined.

  10. Lunar magnetism. [primordial core model

    NASA Technical Reports Server (NTRS)

    Goldstein, M. L.

    1975-01-01

    It is shown, for a very simple model of the moon, that the existence of a primordial core magnetic field would give rise to a present day nonzero dipole external field. In the investigation a uniformly magnetized core embedded in a permeable mantle is considered. The significance of the obtained results for the conclusions reported by Runcorn (1975) is discussed. Comments provided by Runcorn to the discussion are also presented.

  11. Precession of the lunar core

    NASA Astrophysics Data System (ADS)

    Meyer, Jennifer; Wisdom, Jack

    2011-01-01

    Goldreich (Goldreich, P. [1967]. J. Geophys. Res. 72, 3135) showed that a lunar core of low viscosity would not precess with the mantle. We show that this is also the case for much of lunar history. But when the Moon was close to the Earth, the Moon's core was forced to follow closely the precessing mantle, in that the rotation axis of the core remained nearly aligned with the symmetry axis of the mantle. The transition from locked to unlocked core precession occurred between 26.0 and 29.0 Earth radii, thus it is likely that the lunar core did not follow the mantle during the Cassini transition. Dwyer and Stevenson (Dwyer, C.A., Stevenson, D.J. [2005]. An Early Nutation-Driven Lunar Dynamo. AGU Fall Meeting Abstracts GP42A-06) suggested that the lunar dynamo needs mechanical stirring to power it. The stirring is caused by the lack of locked precession of the lunar core. So, we do not expect a lunar dynamo powered by mechanical stirring when the Moon was closer to the Earth than 26.0-29.0 Earth radii. A lunar dynamo powered by mechanical stirring might have been strongest near the Cassini transition.

  12. Precession of the Lunar Core

    NASA Astrophysics Data System (ADS)

    Meyer, J.; Wisdom, J.

    2011-10-01

    Goldreich [3] showed that a lunar core of low viscosity would not precess with the mantle. We show that this is also the case for much of lunar history. But when the Moon was close to the Earth the Moon's core was forced to follow closely the precessing mantle, in that the rotation axis of the core remained nearly aligned with the symmetry axis of the mantle. The transition from locked to unlocked core precession occurred between 26.0 and 29.0 Earth radii, thus it is likely that the lunar core did not follow the mantle during the Cassini transition. Dwyer and Stevenson [1] suggested that the lunar dynamo needs mechanical stirring to power it. The stirring is caused by the lack of locked precession of the lunar core. So, we do not expect a lunar dynamo powered by mechanical stirring when the Moon was closer to the Earth than 26.0 to 29.0 Earth radii. A lunar dynamo powered by mechanical stirring might have been strongest near the Cassini transition.

  13. Bonding core mating surfaces improves transformer

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1978-01-01

    Modifications to assembly procedures for C-core transformers virtually eliminates changes in core end gaps due to temperature cycling during impregnation and potting stages, thus stabilizing magnetization properties of core.

  14. The Effect of Core Configuration on Thermal Barrier Thermal Performance

    NASA Technical Reports Server (NTRS)

    DeMange, Jeffrey J.; Bott, Robert H.; Druesedow, Anne S.

    2015-01-01

    Thermal barriers and seals are integral components in the thermal protection systems (TPS) of nearly all aerospace vehicles. They are used to minimize heat transfer through interfaces and gaps and protect underlying temperature-sensitive components. The core insulation has a significant impact on both the thermal and mechanical properties of compliant thermal barriers. Proper selection of an appropriate core configuration to mitigate conductive, convective and radiative heat transfer through the thermal barrier is challenging. Additionally, optimization of the thermal barrier for thermal performance may have counteracting effects on mechanical performance. Experimental evaluations have been conducted to better understand the effect of insulation density on permeability and leakage performance, which can significantly impact the resistance to convective heat transfer. The effect of core density on mechanical performance was also previously investigated and will be reviewed. Simple thermal models were also developed to determine the impact of various core parameters on downstream temperatures. An extended understanding of these factors can improve the ability to design and implement these critical TPS components.

  15. Dynamic Cores in Hydrostatic Disguise

    NASA Astrophysics Data System (ADS)

    Ballesteros-Paredes, Javier; Klessen, Ralf S.; Vázquez-Semadeni, Enrique

    2003-07-01

    We discuss the column density profiles of ``cores'' in three-dimensional smoothed particle hydrodynamics (SPH) numerical simulations of turbulent molecular clouds. The SPH scheme allows us to perform a high spatial resolution analysis of the density maxima (cores) at scales between ~0.003 and 0.3 pc. We analyze simulations in three different physical conditions: large-scale driving (LSD), small-scale driving (SSD), and random Gaussian initial conditions without driving (GC), each one at two different time steps: just before self-gravity is turned on (t0) and when gravity has been operating such that 5% of the total mass in the box has been accreted into cores (t1). For this data set, we perform Bonnor-Ebert fits to the column density profiles of cores found by a clump-finding algorithm. We find that, for the particular fitting procedure we use, 65% of the cores can be matched to Bonnor-Ebert (BE) profiles, and of these, 47% correspond to stable equilibrium configurations with ξmax<6.5, even though the cores analyzed in the simulations are not in equilibrium but instead are dynamically evolving. The temperatures obtained with the fitting procedure vary between 5 and 60 K (in spite of the simulations being isothermal, with T=11.3 K), with the peak of the distribution being at T=11 K and most clumps having fitted temperatures between 5 and 30 K. Central densities obtained with the BE fit tend to be smaller than the actual central densities of the cores. We also find that for the LSD and GC cases, there are more BE-like cores at t0 than at t1 with ξmax<=20, while in the case of SSD, there are more such cores at t1 than at t0. We interpret this as a consequence of the stronger turbulence present in the cores of run SSD, which prevents good BE fits in the absence of gravity, and delays collapse in its presence. Finally, in some cases we find substantial superposition effects when we analyze the projection of the density structures, even though the scales over which we

  16. 38 CFR 0.601 - Core Values.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Core Values. VA's Core Values define VA employees. They describe the organization's culture and... their individual responsibilities and organizational responsibilities. (c) Advocacy. VA employees...

  17. 38 CFR 0.601 - Core Values.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Core Values. VA's Core Values define VA employees. They describe the organization's culture and... their individual responsibilities and organizational responsibilities. (c) Advocacy. VA employees...

  18. Counterrotating cores in elliptical galaxies

    NASA Astrophysics Data System (ADS)

    Balcella, Marc Comas

    The dynamics of the merger between a high- and a low-elliptical galaxy was studied to understand how kinematically peculiar cores in elliptical galaxies might form. Numerical simulations of mergers provide rotation curves, surface density profiles, surface density contour plots and velocity maps of the merger remnants, as well as diagnostics on the dynamics such as phase-space diagrams. This type of merger can create counterrotating cores. The core of the smaller galaxy, of higher density, is not disrupted by the primary tidal field and sinks to the center of the primary as an independent dynamical subsystem. Core counterrotation occurs only when the initial merger orbit is retrograde with respect to the pin of the primary. The remnant has higher effective radius and lower mean central surface density than the primary galaxy, but a smaller core radius. The adsorption of orbital energy and angular momentum by the primary particles greatly modifies the kinematic structure of the larger galaxy. Twisted rotation axes and isophote twists appear over the whole body of the remnant. These diagnostics may be used to determine whether observed peculiar cores might have formed via an elliptical-elliptical merger. Galaxies with counterrotating cores should show a complex velocity field, isophotal irregularities, and, in general, a slow rotation in the main body of the galaxy. The present experiments are the first galaxy-satellite merger experiments involving an active, rotating secondary. They show that part of the orbital angular momentum is absorbed by the secondary, thus the secondary contributes to its own sinking: the sinking rate depends on the orientation of the secondary spin. Long-slit spectroscopic observations of NGC 3656 are reported.

  19. EVERY BCG WITH A STRONG RADIO AGN HAS AN X-RAY COOL CORE: IS THE COOL CORE-NONCOOL CORE DICHOTOMY TOO SIMPLE?

    SciTech Connect

    Sun, M.

    2009-10-20

    The radio active galactic nucleus (AGN) feedback in X-ray cool cores has been proposed as a crucial ingredient in the evolution of baryonic structures. However, it has long been known that strong radio AGNs also exist in 'noncool core' clusters, which brings up the question whether an X-ray cool core is always required for the radio feedback. In this work, we present a systematic analysis of brightest cluster galaxies (BCGs) and strong radio AGNs in 152 groups and clusters from the Chandra archive. All 69 BCGs with radio AGN more luminous than 2 x 10{sup 23} W Hz{sup -1} at 1.4 GHz are found to have X-ray cool cores. BCG cool cores can be divided into two classes: the large cool core (LCC) class and the corona class. Small coronae, easily overlooked at z > 0.1, can trigger strong heating episodes in groups and clusters, long before LCCs are formed. Strong radio outbursts triggered by coronae may destroy embryonic LCCs and thus provide another mechanism to prevent the formation of LCCs. However, it is unclear whether coronae are decoupled from the radio feedback cycles as they have to be largely immune to strong radio outbursts. Our sample study also shows the absence of groups with a luminous cool core while hosting a strong radio AGN, which is not observed in clusters. This points to a greater impact of radio heating on low-mass systems than clusters. Few L {sub 1.4GHz} > 10{sup 24} W Hz{sup -1} radio AGNs (approx16%) host an L {sub 0.5-10keV} > 10{sup 42} erg s{sup -1} X-ray AGN, while above these thresholds, all X-ray AGNs in BCGs are also radio AGNs. As examples of the corona class, we also present detailed analyses of a BCG corona associated with a strong radio AGN (ESO 137-006 in A3627) and one of the faintest coronae known (NGC 4709 in the Centaurus cluster). Our results suggest that the traditional cool core/noncool core dichotomy is too simple. A better alternative is the cool core distribution function, with the enclosed X-ray luminosity or gas mass.

  20. Core and Off-Core Processes in Systems Engineering

    NASA Technical Reports Server (NTRS)

    Breidenthal, Julian; Forsberg, Kevin

    2010-01-01

    An emerging methodology of organizing systems-engineering plans is based on a concept of core and off-core processes or activities. This concept has emerged as a result of recognition of a risk in the traditional representation of systems-engineering plans by a Vee model alone, according to which a large system is decomposed into levels of smaller subsystems, then integrated through levels of increasing scope until the full system is constructed. Actual systems-engineering activity is more complicated, raising the possibility that the staff will become confused in the absence of plans which explain the nature and ordering of work beyond the traditional Vee model.

  1. Counterrotating Cores in Elliptical Galaxies.

    NASA Astrophysics Data System (ADS)

    Balcells, Marc Comas

    The dynamics of the merger between a high- and a low-luminosity elliptical galaxy has been studied to understand how kinematically peculiar cores in elliptical galaxies might form. Numerical simulations of mergers provide rotation curves, surface density profiles, surface density contour plots and velocity maps of the merger remnants, as well as diagnostics on the dynamics such as phase-space diagrams. This type of merger can create counterrotating cores. The core of the smaller galaxy, of higher density, is not disrupted by the primary tidal field and sinks to the center of the primary as an independent dynamical subsystem. Core counterrotation occurs only when the initial merger orbit is retrograde with respect to the spin of the primary. The remnant has higher effective radius and lower mean central surface density than the primary galaxy, but a smaller core radius. The adsorption of orbital energy and angular momentum by the primary particles greatly modifies the kinematic structure of the larger galaxy. Twisted rotation axes and isophote twists appear over the whole body of the remnant. These diagnostics may be used to determine whether observed peculiar cores might have formed via an elliptical-elliptical merger. Galaxies with counterrotating cores should show a complex velocity field, isophotal irregularities, and, in general, a slow rotation in the main body of the galaxy. The present experiments are the first galaxy-satellite merger experiments involving an active, rotating secondary. They show that part of the orbital angular momentum is absorbed by the secondary, thus the secondary contributes to its own sinking: the sinking rate depends on the orientation of the secondary spin. Long-slit spectroscopic observations of NGC 3656 are reported. Rotation curves indicate that NGC 3656 contains a core spinning in a direction perpendicular to the rotation in the main body of the galaxy. Velocity reversals at intermediate radii are also observed. These features

  2. Issues of Sustainable Redevelopment of City Core: A Study of Developed and Developing Countries

    NASA Astrophysics Data System (ADS)

    Munoth, N.; Jain, R. K.; Raheja, G.; Brar, T. S.

    2013-05-01

    The inner city core has undergone maximum misuse and transformation in the absence of building bye laws and regulation, resulting in decay and dilapidated buildings. These city core areas have been places of life, vitality, wealth, power, enlightenment and culture. However these inner city areas have become marginalized in the process of urban growth and has problems related to decay, dwindling economic conditions and dilapidation leading to migration of the population to better and modern areas. This study intends to investigate the impacts of redevelopment within the core area of developed and developing countries, involving environmental, technical, socioeconomic and legal issues that may influence the attainment of sustainable targets for city core redevelopment.

  3. [Core values in family medicine revisited].

    PubMed

    Álvarez Montero, Santiago

    2017-04-01

    Family medicine has to continually reinvent itself around a core of values that constitutes its navigation system. But accurate data on its impact on the health of people will account for how far the values are actually being implemented. Thus, we can say that family medicine is a specialty based on values and as well as evidence based. The absence of a clarification system of values or its implementation threatens its very existence. Some of the values that are reviewed have shown great recognition and survival over time. Others are presented because they seem sufficiently significant. These are: people, comprehensiveness, trust relationship, patient-centred method, accessibility, continuity, family unity and the community, teamwork, sustainability of the health system, and continuous improvement.

  4. Reactor core isolation cooling system

    DOEpatents

    Cooke, F.E.

    1992-12-08

    A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom. 1 figure.

  5. Reactor core isolation cooling system

    DOEpatents

    Cooke, Franklin E.

    1992-01-01

    A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom.

  6. Identifying ELIXIR Core Data Resources

    PubMed Central

    Durinx, Christine; McEntyre, Jo; Appel, Ron; Apweiler, Rolf; Barlow, Mary; Blomberg, Niklas; Cook, Chuck; Gasteiger, Elisabeth; Kim, Jee-Hyub; Lopez, Rodrigo; Redaschi, Nicole; Stockinger, Heinz; Teixeira, Daniel; Valencia, Alfonso

    2017-01-01

    The core mission of ELIXIR is to build a stable and sustainable infrastructure for biological information across Europe. At the heart of this are the data resources, tools and services that ELIXIR offers to the life-sciences community, providing stable and sustainable access to biological data. ELIXIR aims to ensure that these resources are available long-term and that the life-cycles of these resources are managed such that they support the scientific needs of the life-sciences, including biological research. ELIXIR Core Data Resources are defined as a set of European data resources that are of fundamental importance to the wider life-science community and the long-term preservation of biological data. They are complete collections of generic value to life-science, are considered an authority in their field with respect to one or more characteristics, and show high levels of scientific quality and service. Thus, ELIXIR Core Data Resources are of wide applicability and usage. This paper describes the structures, governance and processes that support the identification and evaluation of ELIXIR Core Data Resources. It identifies key indicators which reflect the essence of the definition of an ELIXIR Core Data Resource and support the promotion of excellence in resource development and operation. It describes the specific indicators in more detail and explains their application within ELIXIR’s sustainability strategy and science policy actions, and in capacity building, life-cycle management and technical actions. The identification process is currently being implemented and tested for the first time. The findings and outcome will be evaluated by the ELIXIR Scientific Advisory Board in March 2017. Establishing the portfolio of ELIXIR Core Data Resources and ELIXIR Services is a key priority for ELIXIR and publicly marks the transition towards a cohesive infrastructure. PMID:27803796

  7. Identifying ELIXIR Core Data Resources.

    PubMed

    Durinx, Christine; McEntyre, Jo; Appel, Ron; Apweiler, Rolf; Barlow, Mary; Blomberg, Niklas; Cook, Chuck; Gasteiger, Elisabeth; Kim, Jee-Hyub; Lopez, Rodrigo; Redaschi, Nicole; Stockinger, Heinz; Teixeira, Daniel; Valencia, Alfonso

    2016-01-01

    The core mission of ELIXIR is to build a stable and sustainable infrastructure for biological information across Europe. At the heart of this are the data resources, tools and services that ELIXIR offers to the life-sciences community, providing stable and sustainable access to biological data. ELIXIR aims to ensure that these resources are available long-term and that the life-cycles of these resources are managed such that they support the scientific needs of the life-sciences, including biological research. ELIXIR Core Data Resources are defined as a set of European data resources that are of fundamental importance to the wider life-science community and the long-term preservation of biological data. They are complete collections of generic value to life-science, are considered an authority in their field with respect to one or more characteristics, and show high levels of scientific quality and service. Thus, ELIXIR Core Data Resources are of wide applicability and usage. This paper describes the structures, governance and processes that support the identification and evaluation of ELIXIR Core Data Resources. It identifies key indicators which reflect the essence of the definition of an ELIXIR Core Data Resource and support the promotion of excellence in resource development and operation. It describes the specific indicators in more detail and explains their application within ELIXIR's sustainability strategy and science policy actions, and in capacity building, life-cycle management and technical actions. The identification process is currently being implemented and tested for the first time. The findings and outcome will be evaluated by the ELIXIR Scientific Advisory Board in March 2017. Establishing the portfolio of ELIXIR Core Data Resources and ELIXIR Services is a key priority for ELIXIR and publicly marks the transition towards a cohesive infrastructure.

  8. Ice Core Dating Software for Interactive Dating of Ice Cores

    NASA Astrophysics Data System (ADS)

    Kurbatov, A. V.; Mayewski, P. A.; Abdul Jawad, B. S.

    2005-12-01

    Scientists involved in ice core dating are well familiar with the problem of identification and recording the depth of annual signals using stable isotopes, glaciochemistry, ECM (electrical conductivity), DEP (dielectric properties) and particle counter data. Traditionally all parameters used for ice core dating were plotted as a function of depth, printed and after years were marked on the paper, converted to depth vs. age time scale. To expedite this tedious and manual process we developed interactive computer software, Ice core Dating (ICD) program. ICD is written in Java programming language, and uses GPL and GPL site licensed graphic libraries. The same 3.5 Mb in size pre-compiled single jar file, that includes all libraries and application code, was successfully tested on WinOS, Mac OSX, Linux, and Solaris operating systems running Java VM version 1.4. We have followed the modular design philosophy in our source code so potential integration with other software modules, data bases and server side distributed computer environments can be easily implemented. We expect to continue development of new suites of tools for easy integration of ice core data with other available time proxies. ICD is thoroughly documented and comes with a technical reference and cookbook that explains the purpose of the software and its many features, and provides examples to help new users quickly become familiar with the operation and philosophy of the software. ICD is available as a free download from the Climate Change Institute web site ( under the terms of GNU GPL public license.

  9. Core Leadership: Teacher Leaders and Common Core Implementation in Tennessee

    ERIC Educational Resources Information Center

    Aspen Institute, 2014

    2014-01-01

    In the summer of 2012, thousands of teachers across the United States attended several days of professional development workshops. The workshops, which focused on the Common Core State Standards, were part of a Tennessee Department of Education initiative in teacher leadership. The department recruited and trained 200 highly-effective teachers to…

  10. Earth's core and the geodynamo

    PubMed

    Buffett

    2000-06-16

    Earth's magnetic field is generated by fluid motion in the liquid iron core. Details of how this occurs are now emerging from numerical simulations that achieve a self-sustaining magnetic field. Early results predict a dominant dipole field outside the core, and some models even reproduce magnetic reversals. The simulations also show how different patterns of flow can produce similar external fields. Efforts to distinguish between the various possibilities appeal to observations of the time-dependent behavior of the field. Important constraints will come from geological records of the magnetic field in the past.

  11. Magnetic Probing of Core Geodynamics

    NASA Technical Reports Server (NTRS)

    Voorhies, Coerte V.

    2004-01-01

    To better understand geomagnetic theory and observation, we can use spatial magnetic spectra for the main field and secular variation to test core dynamical hypotheses against seismology. The hypotheses lead to theoretical spectra which are fitted to observational spectra. Each fit yields an estimate of the radius of Earth's core and uncertainty. If this agrees with the seismologic value, then the hypothesis passes the test. A new way to obtain theoretical spectra extends the hydromagnetic scale analysis of Benton to scale-variant field and flow. For narrow scale flow and a dynamically weak field by the top of Earth's core, this yields a generalized Stevenson-McLeod spectrum for the core-source field, and a secular variation spectrum modulated by a cubic polynomial in spherical harmonic degree n. The former passes the tests. The latter passes many tests, but does not describe rapid dipole decline and quadrupole rebound; some tests suggest it is a bit hard, or rich in narrow scale range. In a core geodynamo, motion of the fluid conductor does work against the Lorentz force. This converts kinetic into magnetic energy which, in turn, is lost to heat via Ohmic dissipation. In the analysis at length-scale 1/k, if one presumes kinetic energy is converted in either eddy-overturning or magnetic free-decay time-scales, then Kolmogorov or other spectra in conflict with observational spectra can result. Instead, the rate work is done roughly balances the dissipation rate, which is consistent with small-scale flow. The conversion time-scale depends on dynamical constraints. These are summarized by the magnetogeostrophic vertical vorticity balance by the top of the core, which includes anisotropic effects of rotation, the magnetic field, and the core-mantle boundary. The resulting theoretical spectra for the core-source field and its SV are far more compatible with observation. The conversion time-scale of order 120 years is pseudo-scale-invariant. Magnetic spectra of other

  12. Magnetic Probing of Core Geodynamics

    NASA Technical Reports Server (NTRS)

    Voorhies, Coerte V.

    2004-01-01

    To better understand geomagnetic theory and observation, we can use spatial magnetic spectra for the main field and secular variation to test core dynmcal hypotheses against seismology. The hypotheses lead to theoretical spectra which are fitted to observational spectra. Each fit yields an estimate of the radius of Earth's core and uncertainty. If this agrees with the seismologic value, then the hypothes pass the test. A new way to obtain theoretical spectra extends the hydromagnetic scale analysis of Benton to scale-variant field and flow. For narrow scale flow and a dynamically weak field by the top of Earth's core, this yields a generalized Stevenson-McLeod spectrum for the core-source field, and a secular variation spectrum modulated by a cubic polynomial in spherical harmonic degree n. The former passes the tests. The latter passes many tests, but does not describe rapid dipole decline and quadrupole rebound; some tests suggest it is a bit hard, or rich in narrow scale change. In a core geodynamo, motion of the fluid conductor does work against the Lorentz force. This converts kinetic into magnetic energy which, in turn, is lost to heat via Ohmic dissipation. In the analysis at lentgh-scale l/k, if one presumes kinetic energy is converted in either eddy- overturning or magnetic free-decay time-scales, then Kolmogorov or other spectra in conflict with observational spectra can result. Instead, the rate work is done roughly balances the dissipation rate, which is consistent with small scale flow. The conversion time-scale depends on dynamical constraints. These are summarized by the magneto-geostrophic vertical vorticity balance by the top of the core, which includes anisotropic effects of rotation, the magnetic field, and the core- mantle boundary. The resulting theoretical spectra for the core-source field and its SV are far more compatible with observation. The conversion time-scale of order l20 years is pseudo-scale-invarient. Magnetic spectra of other

  13. Core competencies in internal medicine.

    PubMed

    Porcel, José Manuel; Casademont, Jordi; Conthe, Pedro; Pinilla, Blanca; Pujol, Ramón; García-Alegría, Javier

    2012-06-01

    The working group on Competencies of Internal Medicine from the Spanish Society of Internal Medicine (SEMI) proposes a series of core competencies that we consider should be common to all European internal medicine specialists. The competencies include aspects related to patient care, clinical knowledge, technical skills, communication skills, professionalism, cost-awareness in medical care and academic activities. The proposal could be used as a working document for the Internal Medicine core curriculum in the context of the educational framework of medical specialties in Europe.

  14. Magnetic Probing of Core Geodynamics

    NASA Astrophysics Data System (ADS)

    Voorhies, C. V.

    2004-05-01

    To better understand geomagnetic theory and observation, we can use spatial magnetic spectra for the main field and secular variation to test core dynamical hypotheses against seismology. The hypotheses lead to theoretical spectra which are fitted to observational spectra. Each fit yields an estimate of the radius of Earth's core and uncertainty. If this agrees with the seismologic value, then the hypotheses pass the test. A new way to obtain theoretical spectra extends the hydromagnetic scale analysis of Benton [1992; GAFD] to scale-variant field and flow [Voorhies, 2004; JGR-SE, in press]. For narrow scale flow and a dynamically weak field by the top of Earth's core, this yields a generalized Stevenson-McLeod spectrum for the core-source field [Voorhies, Sabaka and Purucker, 2002; JGR-P], and a secular variation spectrum modulated by a cubic polynomial in spherical harmonic degree n. The former passes the tests. The latter passes many tests, but does not describe rapid dipole decline and quadrupole rebound; some tests suggest it is a bit hard, or rich in narrow scale change. In a core geodynamo, motion of the fluid conductor does work against the Lorentz force. This converts kinetic into magnetic energy which, in turn, is lost to heat via Ohmic dissipation. In the analysis at length-scale 1/k, if one presumes kinetic energy is converted in either eddy-overturning or magnetic free-decay time-scales, then Kolmogorov or other spectra in conflict with observational spectra can result. Instead, the rate work is done roughly balances the dissipation rate, which is consistent with small scale flow. The conversion time-scale depends on dynamical constraints. These are summarized by the magneto-geostrophic vertical vorticity balance by the top of the core, which includes anisotropic effects of rotation, the magnetic field, and the core-mantle boundary. The resulting theoretical spectra for the core-source field and its SV are far more compatible with observation. The

  15. Depositional history of the Apollo 16 deep drill core

    NASA Technical Reports Server (NTRS)

    Gose, W. A.; Morris, R. V.

    1977-01-01

    Ferromagnetic resonance and magnetic hysteresis loop measurements were performed on 212 samples from the Apollo 16 deep drill core. The total iron content is generally uniform with a mean value of 5.7 plus or minus 0.9 wt%. The soils range in maturity from immature to mature. Two major contacts were observed. The contact at 13 cm depth represents a fossil surface whereas the contact at 190 cm depth has no time-stratigraphic significance. The data suggest that the core section below 13 cm depth was deposited in a single impact event and subjected to meteoritic gardening for about 450 m.y. However, our data do not preclude deposition by a series of closely spaced events. About 50 m.y. ago, the top 13 cm were added. Comparison with the Apollo 16 double drive tube 60009/60010 does not yield any evidence for a stratigraphic correlation with the deep drill core.

  16. The Core of the Moon - Molten or Solid?

    NASA Technical Reports Server (NTRS)

    Khan, A.; Mosegaard, K.; Williams, J. G.; Lognonne, P.

    2005-01-01

    While several studies beginning in the Apollo era and continuing up to the present have tried to detect the lunar core, either geochemically, geophysically or geologically [e.g. 1, 2, 3, 4], it has so far proven somewhat elusive. The unambiguous detection of the lunar core is of prime importance as it holds the potential of distinguishing between the various theories for the formation of the Moon. The theory which currently enjoys the greatest success is the giant impact model, which has the Moon forming about 4.5 Gyr ago from the debris produced when a Mars sized proto planet collided with the proto Earth [e.g. 5, 6]. Simulations reveal that the material from which the Moon is made up contains very little iron and consequently a lunar core, if it exists, should be small.

  17. Assessment of HCDA energetics in the CRBRP heterogeneous reactor core

    SciTech Connect

    Rhow, S K; Switick, D M; McElroy, J L; Joe, B W; Elawar, Z J

    1981-03-27

    The results of hypothetical core disruptive event analyses for the CRBRP heterogeneous reactor core are reported. The analytical results cover a large number of parametric cases including variations in design parameters and phenomenological assumptions. Reactor core configurations at the beginning of cycle one and end of cycle four are evaluated. The energetic consequences are evaluated based upon both fuel expansion thermodynamic work potential and a relative probability assignment. It is concluded that the structural loads, which result from 101 megajoules of available expansion work at sodium slug impact on the reactor closure head (equivalent to 661 megajoules of fuel expansion work to one atmosphere), is an adequate energetic consequence envelope for use in specifying the Structural Margins Beyond the Design Basis.

  18. City Core - detecting the anthropocene in urban lake cores

    NASA Astrophysics Data System (ADS)

    Kjaer, K. H.; Ilsøe, P.; Andresen, C. S.; Rasmussen, P.; Andersen, T. J.; Frei, R.; Schreiber, N.; Odgaard, B.; Funder, S.; Holm, J. M.; Andersen, K.

    2011-12-01

    Here, we presents the preliminary results from lake cores taken in ditches associated with the historical fortifications enclosing the oldest - central Copenhagen to achieve new knowledge from sediment deposits related to anthropogenic activities. We have examined sediment cores with X-ray fluorescence (XRF) analyzers to correlate element patterns from urban and industrial emissions. Thus, we aim to track these patterns back in time - long before regular routines of recording of atmospheric environment began around 1978. Furthermore, we compare our data to alternative sources of information in order to constrain and expand the temporal dating limits (approximately 1890) achieved from 210Pb activity. From custom reports and statistic sources, information on imported volumes from coal, metal and oil was obtained and related contaminants from these substances to the sediment archives. Intriguingly, we find a steep increase in import of coal and metals matching the exponential increase of lead and zinc counts from XRF-recordings of the sediment cores. In this finding, we claim to have constrain the initiation of urban industrialization. In order to confirm the age resolution of the lake cores, DNA was extracted from sediments, sedaDNA. Thus we attempt to trace plantation of well documented exotic plants to, for instance, the Botanical Garden. Through extraction and sampling of sedaDNA from these floral and arboreal specimens we intend to locate their strataigraphic horizons in the sediment core. These findings may correlate data back to 1872, when the garden was established on the area of the former fortification. In this line of research, we hope to achieve important supplementary knowledge of sedaDNA-leaching frequencies within freshwater sediments.

  19. Producing gapped-ferrite transformer cores

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1980-01-01

    Improved manufacturing techniques make reproducible gaps and minimize cracking. Molded, unfired transformer cores are cut with thin saw and then fired. Hardened semicircular core sections are bonded together, placed in aluminum core box, and fluidized-coated. After winding is run over box, core is potted. Economical method significantly reduces number of rejects.

  20. Gelcasting Alumina Cores for Investment Casting

    SciTech Connect

    Janney, M A; Klug, F J

    2001-01-01

    General Electric currently uses silica investment casting cores for making superalloy turbine blades. The silica core technology does not provide the degree of dimensional control needed for advanced turbine system manufacture. The sum of the various process variables in silica core manufacturing produces cores that have more variability than is allowed for in advanced, power-generation gas turbine airfoils.

  1. High Impact Technology Compact Combustion (HITCC) Compact Core Technologies

    DTIC Science & Technology

    2016-01-01

    correlation as the chemical “timescale.” The resulting correlation equation is Eq 22. Including laminar flame speed improved the R-squared value from...including: 1) ultra-compact combustors, 2) inter-turbine burner concepts, 3) bluff-body stabilized turbulent flames, 4) well-stirred reactors for... chemical kinetics, and 5) detonation-stabilized turbulent flames. Lean blowout data was collected on propane and jet fuel bluff-body stabilized flames

  2. Visual Feedback for Rover-based Coring

    NASA Technical Reports Server (NTRS)

    Backes, Paul; Helmick, Daniel; Bajracharya, Max

    2008-01-01

    Technology for coring from a low-mass rover has been developed to enable core sample acquisition where a planetary rover experiences moderate slip during the coring operation. A new stereo vision technique, Absolute Motion Visual Odometry, is used to measure rover slip during coring and the slip is accommodated through corresponding arm pose updating. Coring rate is controlled by feedback of themeasured force of the coring tool against the environment. Test results in the JPL Marsyard show for the first time that coring from a low-mass rover with slip is feasible.

  3. Tidal Excitation of the Core Dynamo of Mars

    NASA Astrophysics Data System (ADS)

    Seyed-Mahmoud, B.; Arkani-Hamed, J.; Aldridge, K.

    2007-05-01

    The lack of magnetic anomalies inside the giant impact basins Hellas, Isidis, Utopia and Argyre, inside the northern low lands, over the Tharsis bulge, and over the Tharsis and Olympus mounts suggests that the core field of Mars ceased to exist by about 4 Gyr ago, almost when the giant basins were formed. On the other hand, the giant basins are located on a great circle, implying that the basins were likely produced by fragments of a large asteroid that broke apart as it entered the Roche limit of Mars. This scenario offers a causative relationship for the apparent coincidence of the formation of the giant basins and the cessation of the core dynamo. We suggest that the core dynamo was excited by tidally driven elliptical instability in the Martian core. The breaking of the asteroid and its final impact on Mars eliminated the excitation and thus killed the dynamo. We show that a retrograde asteroid captured in a Keplerian orbit around Mars at a distance of about 50,000-100,000 km could orbit Mars for several hundreds of millions of years before impacting the planet due to the tidal coupling of the asteroid and Mars. Because of relatively very short growth time of the elliptical instability, less than 50,000 years, the asteroid was capable of retaining the elliptical instability and energizing the core dynamo for a geologically long period prior to 4 Ga. Our laboratory observations of a parametric instability of a rotating incompressible fluid, contained in a flexible-walled spherical cavity, confirm the possibility that an early Martian dynamo could have been powered by tidal straining.

  4. Core-melt source reduction system

    DOEpatents

    Forsberg, Charles W.; Beahm, Edward C.; Parker, George W.

    1995-01-01

    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.

  5. Core-melt source reduction system

    DOEpatents

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

    1995-04-25

    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.

  6. Experience with the BEACON core monitoring system

    SciTech Connect

    Beard, C.L. ); Icide, C.A. )

    1992-01-01

    The BEACON operational core support system was developed for use in pressurized water reactors to provide an integrated system to perform reactor core monitoring, core measurement reduction, core analysis and follow, and core predictions. It is based on the very fast and accurate three-dimensional SPNOVA nodal program. The experience to date has shown the importance of an accurate integrated system. The benefits accrued are greater for the total system than the benefits that are possible separately.

  7. Laminated grid and web magnetic cores

    DOEpatents

    Sefko, John; Pavlik, Norman M.

    1984-01-01

    A laminated magnetic core characterized by an electromagnetic core having core legs which comprise elongated apertures and edge notches disposed transversely to the longitudinal axis of the legs, such as high reluctance cores with linear magnetization characteristics for high voltage shunt reactors. In one embodiment the apertures include compact bodies of microlaminations for more flexibility and control in adjusting permeability and/or core reluctance.

  8. Stellar core collapse and supernova

    SciTech Connect

    Wilson, J.R.; Mayle, R.; Woosley, S.E.; Weaver, T.

    1985-04-01

    Massive stars that end their stable evolution as their iron cores collapse to a neutron star or black hole long been considered good candidates for producing Type II supernovae. For many years the outward propagation of the shock wave produced by the bounce of these iron cores has been studied as a possible mechanism for the explosion. For the most part, the results of these studies have not been particularly encouraging, except, perhaps, in the case of very low mass iron cores or very soft nuclear equations of state. The shock stalls, overwhelmed by photodisintegration and neutrino losses, and the star does not explode. More recently, slow late time heating of the envelope of the incipient neutron star has been found to be capable of rejuvenating the stalled shock and producing an explosion after all. The present paper discusses this late time heating and presents results from numerical calculations of the evolution, core collapse, and subsequent explosion of a number of recent stellar models. For the first time they all, except perhaps the most massive, explode with reasonable choices of input physics. 39 refs., 17 figs., 1 tab.

  9. Common Core State Standards 101

    ERIC Educational Resources Information Center

    Rothman, Robert

    2013-01-01

    The Common Core State Standards (CCSS) represent the first time that nearly every state has set common expectations for what students should know and be able to do. In the past, each state set its own standards, and the results varied widely. And while states collectively developed these common standards, decisions about the curriculum and…

  10. Large core fiber optic cleaver

    DOEpatents

    Halpin, John M.

    1996-01-01

    The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 .mu.m.

  11. Droplet Core Nuclear Rocket (DCNR)

    NASA Technical Reports Server (NTRS)

    Anghaie, Samim

    1991-01-01

    The most basic design feature of the droplet core nuclear reactor is to spray liquid uranium into the core in the form of droplets on the order of five to ten microns in size, to bring the reactor to critical conditions. The liquid uranium fuel ejector is driven by hydrogen, and more hydrogen is injected from the side of the reactor to about one and a half meters from the top. High temperature hydrogen is expanded through a nozzle to produce thrust. The hydrogen pressure in the system can be somewhere between 50 and 500 atmospheres; the higher pressure is more desirable. In the lower core region, hydrogen is tangentially injected to serve two purposes: (1) to provide a swirling flow to protect the wall from impingement of hot uranium droplets: (2) to generate a vortex flow that can be used for fuel separation. The reactor is designed to maximize the energy generation in the upper region of the core. The system can result in and Isp of 2000 per second, and a thrust-to-weight ratio of 1.6 for the shielded reactor. The nuclear engine system can reduce the Mars mission duration to less than 200 days. It can reduce the hydrogen consumption by a factor of 2 to 3, which reduces the hydrogen load by about 130 to 150 metric tons.

  12. 10 Core External Environmental Trends.

    ERIC Educational Resources Information Center

    El Camino Coll., Torrance, CA.

    This is an institutional report summarizing 10 core external environmental trends and their implications for El Camino College and the surrounding community. The report offers a brief description for the following trends: (1) there is more emphasis on colleges becoming learning institutions rather than teaching institutions; (2) the current and…

  13. Stability of Molten Core Materials

    SciTech Connect

    Layne Pincock; Wendell Hintze

    2013-01-01

    The purpose of this report is to document a literature and data search for data and information pertaining to the stability of nuclear reactor molten core materials. This includes data and analysis from TMI-2 fuel and INL’s LOFT (Loss of Fluid Test) reactor project and other sources.

  14. The fluffy core of Enceladus

    NASA Astrophysics Data System (ADS)

    Roberts, James H.

    2015-09-01

    Enceladus is well known for its young south polar terrain, observed by Cassini to emit several GW of heat as well as plumes of vapor and ice. The source of this energy is believed to be tidal dissipation. However, the observed south polar heat flux cannot be sustained over the age of the Solar System. Furthermore, thermal evolution models suggest that any global subsurface ocean should freeze on a timescale of tens to hundreds of My, sharply reducing future tidal heating, unless large amounts of antifreeze are present in the ocean. Here I propose an alternative internal structure for Enceladus, in which the silicate core is fragmented, and that the tidal deformation of the core may be partially controlled by interstitial ice. I find that fragmentation of the core increases tidal dissipation by a factor of 20, consistent with the long-term dynamically sustainable level, even when the interior is completely frozen, but only if the interior starts out warm and tidal heating is strong from the beginning. If this is not the case, radioactive heating will be insufficient to prevent the interior from cooling. Although an ocean need not be present in order for the interior to experience significant tidal heating, all models that dissipate enough heat to prevent runaway cooling are also warm enough to have an ocean. Tidal dissipation in the weak core provides an additional source of heat that may prevent a global subsurface ocean from freezing.

  15. Earth rotation and core topography

    NASA Technical Reports Server (NTRS)

    Hager, Bradford H.; Clayton, Robert W.; Spieth, Mary Ann

    1988-01-01

    The NASA Geodynamics program has as one of its missions highly accurate monitoring of polar motion, including changes in length of day (LOD). These observations place fundamental constraints on processes occurring in the atmosphere, in the mantle, and in the core of the planet. Short-timescale (t less than or approx 1 yr) variations in LOD are mainly the result of interaction between the atmosphere and the solid earth, while variations in LOD on decade timescales result from the exchange of angular momentum between the mantle and the fluid core. One mechanism for this exchange of angular momentum is through topographic coupling between pressure variations associated with flow in the core interacting with topography at the core-mantel boundary (CMB). Work done under another NASA grant addressing the origin of long-wavelength geoid anomalies as well as evidence from seismology, resulted in several models of CMB topography. The purpose of work supported by NAG5-819 was to study further the problem of CMB topography, using geodesy, fluid mechanics, geomagnetics, and seismology. This is a final report.

  16. Common Core: Solve Math Problems

    ERIC Educational Resources Information Center

    Strom, Erich

    2012-01-01

    The new common core standards for mathematics demand that students (and teachers!) exhibit deeper conceptual understanding. That's music to the ears of education professor John Tapper, who says teachers have overemphasized teaching procedures--and getting right answers. In his new book, "Solving for Why," he makes a powerful case for moving beyond…

  17. Large core fiber optic cleaver

    DOEpatents

    Halpin, J.M.

    1996-03-26

    The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 {micro}m. 30 figs.

  18. [Core competencies in internal medicine].

    PubMed

    Porcel, J M; Casademont, J; Conthe, P; Pinilla, B; Pujol, R; García-Alegría, J

    2011-06-01

    The working group of the Spanish Society of Internal Medicine (SEMI) on "Competencies of the Internist" has defined the basic medical knowledge, skills and attitudes that all internists in Spain should have. This list of competencies represents the Internal Medicine core curriculum within the context of the future educational framework of medical specialties in Health Sciences.

  19. Common Core: Fact vs. Fiction

    ERIC Educational Resources Information Center

    Greene, Kim

    2012-01-01

    Despite students' interest in informational text, it has played second fiddle in literacy instruction for years. Now, though, nonfiction is getting its turn in the spotlight. The Common Core State Standards require that students become thoughtful consumers of complex, informative texts--taking them beyond the realm of dry textbooks and…

  20. "Common Core Implementation Best Practices"

    ERIC Educational Resources Information Center

    Martin, Carmel

    2014-01-01

    This document presents the testimony of Carmel Martin, Executive Vice President for Policy at the Center for American Progress, delivered at the New York State Office of the Governor Common Core Implementation Panel on Wednesday, February 19, 2014. In this statement, Martin began by saying that The Center for American Progress believes that this…

  1. One Health Core Competency Domains

    PubMed Central

    Frankson, Rebekah; Hueston, William; Christian, Kira; Olson, Debra; Lee, Mary; Valeri, Linda; Hyatt, Raymond; Annelli, Joseph; Rubin, Carol

    2016-01-01

    The emergence of complex global challenges at the convergence of human, animal, and environmental health has catalyzed a movement supporting “One Health” approaches. Despite recognition of the importance of One Health approaches to address these complex challenges, little effort has been directed at identifying the seminal knowledge, skills, and attitudes necessary for individuals to successfully contribute to One Health efforts. Between 2008 and 2011, three groups independently embarked on separate initiatives to identify core competencies for professionals involved with One Health approaches. Core competencies were considered critically important for guiding curriculum development and continuing professional education, as they describe the knowledge, skills, and attitudes required to be effective. A workshop was convened in 2012 to synthesize the various strands of work on One Health competencies. Despite having different mandates, participants, and approaches, all of these initiatives identified similar core competency domains: management; communication and informatics; values and ethics; leadership; teams and collaboration; roles and responsibilities; and systems thinking. These core competency domains have been used to develop new continuing professional education programs for One Health professionals and help university curricula prepare new graduates to be able to contribute more effectively to One Health approaches. PMID:27679794

  2. Common Core: Rx for Change

    ERIC Educational Resources Information Center

    Jaeger, Paige

    2012-01-01

    When David Coleman, one of the authors of the Common Core State Standards (CCSS), spoke to New York educators, he stated that over the last forty years 8th grade reading scores have been flat. Despite doubling expenditures on classroom instruction, there has been little growth. Most educators are aware that what worked for the students of the…

  3. CopperCore Service Integration

    ERIC Educational Resources Information Center

    Vogten, Hubert; Martens, Harrie; Nadolski, Rob; Tattersall, Colin; van Rosmalen, Peter; Koper, Rob

    2007-01-01

    In an e-learning environment there is a need to integrate various e-learning services like assessment services, collaboration services, learning design services and communication services. In this article we present the design and implementation of a generic integrative service framework, called CopperCore Service Integration (CCSI). We will…

  4. Wasting Away: Chicago's Declining Core

    ERIC Educational Resources Information Center

    Kissel, Adam

    2009-01-01

    The University of Chicago met widespread national opposition ten years ago after it instituted a new, less demanding core curriculum to make way for more electives. It was part of a plan to make the curriculum significantly less demanding in order to attract more students and improve the school's bottom line in a time of putative budget deficits.…

  5. A Core Program in JIAFS

    NASA Technical Reports Server (NTRS)

    Whitesides, John L.

    2000-01-01

    This paper presents a final report on A Core Program in JIAFS (Joint Institute for Advancement of Flight Sciences). The objectives of the program were to conduct high-risk innovative research, administer and direct the on-going programs, and appoint additional Graduate Research Scholar Assistants depending on availability of applicants and funds.

  6. Advanced neutron source reactor conceptual safety analysis report, three-element-core design: Chapter 15, accident analysis

    SciTech Connect

    Chen, N.C.J.; Wendel, M.W.; Yoder, G.L.; Harrington, R.M.

    1996-02-01

    In order to utilize reduced enrichment fuel, the three-element-core design for the Advanced Neutron Source has been proposed. The proposed core configuration consists of inner, middle, and outer elements, with the middle element offset axially beneath the inner and outer elements, which are axially aligned. The three-element-core RELAP5 model assumes that the reactor hardware is changed only within the core region, so that the loop piping, heat exchangers, and pumps remain as assumed for the two-element-core configuration. To assess the impact of changes in the core region configuration and the thermal-hydraulic steady-state conditions, the safety analysis has been updated. This report gives the safety margins for the loss-of-off-site power and pressure-boundary fault accidents based on the RELAP5 results. AU margins are greater for the three-element-core simulations than those calculated for the two-element core.

  7. Magnectic Probing of Core Geodynamics

    NASA Technical Reports Server (NTRS)

    Voorhies, Coerte

    2004-01-01

    To better understand geomagnetic theory and observation, we can use spatial magnetic spectra for the main field and secular variation to test core dynamical hypotheses against seismology. The hypotheses lead to theoretical spectra which are fitted to observational spectra. Each fit yields an estimate of the radius of Earth s core and uncertainty. If this agrees with the seismologic value, then the hypotheses pass the test. A new way to obtain theoretical spectra extends the hydromagnetic scale analysis of Benton to scale-variant field and flow. For narrow scale flow and a dynamically weak field by the top of Earth s core, this yields a JGR-PI, and a secular variation spectrum modulated by a cubic polynomial in spherical harmonic degree n. The former passes the tests. The latter passes many tests, but does not describe rapid dipole decline and quadrupole rebound; some tests suggest it is a bit hard, or rich in narrow scale change.In a core geodynamo, motion of the fluid conductor does work against the Lorentz force. This converts kinetic into magnetic energy which, in turn, is lost to heat via Ohmic dissipation. In the analysis at length- scale l/k, if one presumes kinetic energy is converted in either eddy- overturning or magnetic free-decay time-scales, then Kolmogorov or other spectra in conflict with observational spectra can result. Instead, the rate work is done roughly balances the dissipation rate, which is consistent with small scale flow. The conversion time-scale depends on dynamical constraints. These are summarized by the magneto- geostrophic vertical vorticity balance by the top of the core, which includes anisotropic effects of rotation, the magnetic field, and the core-mantle boundary. The resulting theoretical spectra for the core- source field and its SV are far more compatible with observation. The conversion time-scale of order 120 years is pseudo-scale-invariant. Magnetic spectra of other planets may differ; however, if a transition to non

  8. Was core formation violent enough to homogenize the early mantle?

    NASA Technical Reports Server (NTRS)

    Cooperman, S. A.; Kaula, W. M.

    1985-01-01

    The dynamics of iron, its thermal state and its phase in the accreting Earth probably played a major role in the Earth's early thermal evolution. Plausible impact thermal histories make it possible that pure iron was molten in the accreting Earth after it was about 10% grown. Hence, iron eutectic alloys (FeS, FeO) certainly were. Additionally, the initial temperature of the core is an important constraint on the secular cooling of the early Earth and on the strength of the early geodynamo. Whether iron is solid or molten would influence geochemical equilibria in the upper and lower mantle; the mode of core formation, by spherical or near-spherical blobs, stalk-like instabilities, or something more catastrophic would influence the partitioning of siderophiles between silicate and iron phases. Early descent of iron (during accretion) favors partitioning according to low-pressure phase equilibria, whereas late descent favors higher pressure. The later core formation occurs, the greater the heat pulse, due to the strong dependence of gravitational potential energy on planetary radius. The heat may homogenize the mantle if core formation is global; otherwise, heterogeneity of iron differentiation may leave some of the pre-archean mantle unaffected. The larger the chunks of proto-core (and hence smaller surface/volume ratios) the greater the heterogeneity.

  9. Core Formation and Evolution of Asteroid 4 Vesta

    NASA Technical Reports Server (NTRS)

    Kiefer, Walter S.; Mittlefehldt, David W.

    2014-01-01

    The howardites, eucrites, and diogenites (HEDs) are a suite of related meteorite types that formed by igneous and impact processes on the same parent body. Multiple lines of evidence, including infrared spectroscopy of the asteroid belt and the petrology and geochemistry of the HEDs, suggest that the asteroid 4 Vesta is the parent body for the HEDs. Observations by NASA's Dawn spacecraft mission strongly support the conclusion that the HEDs are from Vesta. The abundances of the moderately siderophile elements Ni, Co, Mo, W, and P in eucrites require that most or all of the metallic phase in Vesta segregated to form a core prior to eucrite solidification. These observations place important constraints on the mode and timescale of core formation on Vesta. Possible core formation mechanisms include porous flow, which potentially could occur prior to initiation of silicate melting, and metallic rain in a largely molten silicate magma ocean. Once the core forms, convection within the core could possible sustain a magnetic dynamo for a period of time. We consider each process in turn.

  10. Sensitivity of tropical cyclone intensification to inner-core structure

    NASA Astrophysics Data System (ADS)

    Ge, Xuyang; Xu, Wei; Zhou, Shunwu

    2015-10-01

    In this study, the dependence of tropical cyclone (TC) development on the inner-core structure of the parent vortex is examined using a pair of idealized numerical simulations. It is found that the radial profile of inner-core relative vorticity may have a great impact on its subsequent development. For a system with a larger inner-core relative vorticity/inertial stability, the conversion ratio of the diabatic heating to kinetic energy is greater. Furthermore, the behavior of the convective vorticity eddies is likely modulated by the system-scale circulation. For a parent vortex with a relatively higher inner-core vorticity and larger negative radial vorticity gradient, convective eddy formation and radially inward propagation is promoted through vorticity segregation. This provides a greater potential for these small-scale convective cells to self-organize into a mesoscale inner-core structure in the TC. In turn, convectively induced diabatic heating that is close to the center, along with higher inertial stability, efficiently enhances system-scale secondary circulation. This study provides a solid basis for further research into how the initial structure of a TC influences storm dynamics and thermodynamics.

  11. Weak-interaction processes in core-collapse supernovae

    SciTech Connect

    Langanke, K.

    2015-02-24

    Weak interaction processes play an important role for the dynamics of a core-collapse supernova. Due to progress of nuclear modeling and constrained by data it has been possible to improve the rates of these processes for supernova conditions decisively. This manuscript describes the recent advances and the current status in deriving electron capture rates on nuclei and of inelastic neutrino-nucleus scattering for applications in supernova simulations and briefly discusses their impact on such studies.

  12. 43 CFR 3593.1 - Core or test hole cores, samples, cuttings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Core or test hole cores, samples, cuttings...) EXPLORATION AND MINING OPERATIONS Bore Holes and Samples § 3593.1 Core or test hole cores, samples, cuttings... all core or test holes made on the lands covered by the lease, license or permit. The records shall...

  13. 43 CFR 3593.1 - Core or test hole cores, samples, cuttings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Core or test hole cores, samples, cuttings...) EXPLORATION AND MINING OPERATIONS Bore Holes and Samples § 3593.1 Core or test hole cores, samples, cuttings... all core or test holes made on the lands covered by the lease, license or permit. The records shall...

  14. 43 CFR 3593.1 - Core or test hole cores, samples, cuttings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Core or test hole cores, samples, cuttings...) EXPLORATION AND MINING OPERATIONS Bore Holes and Samples § 3593.1 Core or test hole cores, samples, cuttings... all core or test holes made on the lands covered by the lease, license or permit. The records shall...

  15. 43 CFR 3593.1 - Core or test hole cores, samples, cuttings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Core or test hole cores, samples, cuttings...) EXPLORATION AND MINING OPERATIONS Bore Holes and Samples § 3593.1 Core or test hole cores, samples, cuttings... officer. The authorized officer may cut such cores and receive samples as appropriate. Upon the request...

  16. Hydrologic characterization of four cores from the Geysers Coring Project

    SciTech Connect

    Persoff, Peter; Hulen, Jeffrey B.

    1996-01-24

    Results of hydrologic tests conducted on four representative core plugs from Geysers Coring Project drill hole SB-15-D have been related to detailed mineralogic and textural characterization of the plugs to yield new information about permeability, porosity, and capillary-pressure characteristics of the uppermost Geysers steam reservoir and its immediately overlying caprock. The core plugs are all fine- to medium-grained, Franciscan-assemblage (late Mesozoic) metagraywacke with sparse Franciscan metamorphic quartz-calcite veins and late Cenozoic, hydrothermal quartz-calcite-pyrite veins. The matrices of three plugs from the caprock are rich in metamorphic mixed-layer illite/smectite and disseminated hydrothermal pyrite; the reservoir plug instead contains abundant illite and only minor pyrite. The reservoir plug and one caprock plug are sparsely disrupted by latest-stage, unmineralized microfractures which both follow and crosscut veinlets but which could be artifacts. Porosities of the plugs, measured by Boyles-law gas expansion, range between 1.9 and 2.5%. Gas permeability and Klinkenberg slip factor were calculated from gas-pressure-pulse-decay measurements using a specially designed permeameter with small (2 mL) reservoirs. Matrix permeabilities in the range 10-21 m² ( = 1 nanodarcy) were measured for two plugs that included mineral-filled veins but no unfilled microfractures. Greater permeabilities were measured on plugs that contained microfractures; at 500 psi net confining pressure, an effective aperture of 1.6 µm was estimated for one plug. Capillary pressure curves were determined for three cores by measuring saturation as weight gain of plugs equilibrated with atmospheres in which the relative humidity was controlled by saturated brines.

  17. Core-core and core-valence correlation energy atomic and molecular benchmarks for Li through Ar

    SciTech Connect

    Ranasinghe, Duminda S.; Frisch, Michael J.; Petersson, George A.

    2015-12-07

    We have established benchmark core-core, core-valence, and valence-valence absolute coupled-cluster single double (triple) correlation energies (±0.1%) for 210 species covering the first- and second-rows of the periodic table. These species provide 194 energy differences (±0.03 mE{sub h}) including ionization potentials, electron affinities, and total atomization energies. These results can be used for calibration of less expensive methodologies for practical routine determination of core-core and core-valence correlation energies.

  18. Effect of width, amplitude, and position of a core mantle boundary hot spot on core convection and dynamo action

    NASA Astrophysics Data System (ADS)

    Dietrich, Wieland; Wicht, Johannes; Hori, Kumiko

    2015-12-01

    Within the fluid iron cores of terrestrial planets, convection and the resulting generation of global magnetic fields are controlled by the overlying rocky mantle. The thermal structure of the lower mantle determines how much heat is allowed to escape the core. Hot lower mantle features, such as the thermal footprint of a giant impact or hot mantle plumes, will locally reduce the heat flux through the core mantle boundary (CMB), thereby weakening core convection and affecting the magnetic field generation process. In this study, we numerically investigate how parametrised hot spots at the CMB with arbitrary sizes, amplitudes, and positions affect core convection and hence the dynamo. The effect of the heat flux anomaly is quantified by changes in global flow symmetry properties, such as the emergence of equatorial antisymmetric, axisymmetric (EAA) zonal flows. For purely hydrodynamic models, the EAA symmetry scales almost linearly with the CMB amplitude and size, whereas self-consistent dynamo simulations typically reveal either suppressed or drastically enhanced EAA symmetry depending mainly on the horizontal extent of the heat flux anomaly. Our results suggest that the length scale of the anomaly should be on the same order as the outer core radius to significantly affect flow and field symmetries. As an implication to Mars and in the range of our model, the study concludes that an ancient core field modified by a CMB heat flux anomaly is not able to heterogeneously magnetise the crust to the present-day level of north-south asymmetry on Mars. The resulting magnetic fields obtained using our model either are not asymmetric enough or, when they are asymmetric enough, show rapid polarity inversions, which are incompatible with thick unidirectional magnetisation.

  19. Logging-while-coring method and apparatus

    DOEpatents

    Goldberg, David S.; Myers, Gregory J.

    2007-11-13

    A method and apparatus for downhole coring while receiving logging-while-drilling tool data. The apparatus includes core collar and a retrievable core barrel. The retrievable core barrel receives core from a borehole which is sent to the surface for analysis via wireline and latching tool The core collar includes logging-while-drilling tools for the simultaneous measurement of formation properties during the core excavation process. Examples of logging-while-drilling tools include nuclear sensors, resistivity sensors, gamma ray sensors, and bit resistivity sensors. The disclosed method allows for precise core-log depth calibration and core orientation within a single borehole, and without at pipe trip, providing both time saving and unique scientific advantages.

  20. Mars: a new core-crystallization regime.

    PubMed

    Stewart, Andrew J; Schmidt, Max W; van Westrenen, Wim; Liebske, Christian

    2007-06-01

    The evolution of the martian core is widely assumed to mirror the characteristics observed for Earth's core. Data from experiments performed on iron-sulfur and iron-nickel-sulfur systems at pressures corresponding to the center of Mars indicate that its core is presently completely liquid and that it will not form an outwardly crystallizing iron-rich inner core, as does Earth. Instead, planetary cooling will lead to core crystallization following either a "snowing-core" model, whereby iron-rich solids nucleate in the outer portions of the core and sink toward the center, or a "sulfide inner-core" model, where an iron-sulfide phase crystallizes to form a solid inner core.

  1. Logging-while-coring method and apparatus

    DOEpatents

    Goldberg, David S.; Myers, Gregory J.

    2007-01-30

    A method and apparatus for downhole coring while receiving logging-while-drilling tool data. The apparatus includes core collar and a retrievable core barrel. The retrievable core barrel receives core from a borehole which is sent to the surface for analysis via wireline and latching tool The core collar includes logging-while-drilling tools for the simultaneous measurement of formation properties during the core excavation process. Examples of logging-while-drilling tools include nuclear sensors, resistivity sensors, gamma ray sensors, and bit resistivity sensors. The disclosed method allows for precise core-log depth calibration and core orientation within a single borehole, and without at pipe trip, providing both time saving and unique scientific advantages.

  2. Short Sediment Cores as Archives of Urban Pollution

    NASA Astrophysics Data System (ADS)

    Latimer, J. C.; McLennan, D. A.; Stone, J.; Memmer, E. D.; Foster, J. A.; Hardin, K. J.; Nickerson, Z.; Portwood, C. A.; Williams, T. M.

    2014-12-01

    Urban areas are host to numerous sources of environmental pollution, including industry, traffic, and past land uses. To document this pollution within Vigo County, Indiana, we collected several short cores from ponds and wetlands throughout the county, including cores from the old industrial park in Terre Haute, nature parks, a lake impacted by acid mine drainage, and a newly restored wetland to investigate heavy metal burial in these aquatic ecosystems. One core was collected from a holding pond that was constructed in the 1950's on the former International Paper (IP) site where corrugated packing products were produced for nearly a century. One of the nature parks (Dobbs Nature Park) was established in 1976, while the other sits on a former Brownfield site and was only recently opened to the public (Maple Avenue Nature Park). Scott Lake is adjacent to an abandoned coal mine, and continues to receive acidic drainage. Wabashiki Fish and Wildlife Area is flooded seasonally by the Wabash River. Prior land uses for the Wabashiki include agriculture and illegal dumping. All of these sites, except IP are designated fishing areas. Based on water chemistry and diatom assemblages, these ponds have acceptable water quality; however, some are becoming increasingly more eutrophic. Preliminary results from the IP and Maple Avenue Nature Park sediment cores indicate elevated heavy metal concentrations above background levels and at concentrations high enough to impact benthic organisms based on NOAA Sediment Quality Guidelines. Diatoms from the IP core suggest a transition from low productivity at the base to nutrient-rich conditions in more recent sediments, and several diatom specimens have observable deformities (typically an indicator of heavy metals). The base of the IP core also has metal concentrations that are 5 times greater than the top of the core. In many cases, sediments from the Maple Avenue Nature Park pond have metal concentrations higher than the surrounding

  3. Velocity coherence in dense cores

    NASA Astrophysics Data System (ADS)

    Goodman, Alyssa A.; Barranco, Joseph A.; Wilner, David J.; Heyer, Mark H.

    1997-02-01

    At the meeting, we presented a summary of two papers which support the hypothesis that the molecular clouds which contain star-forming low-mass dense cores are self-similar in nature on size scales larger than an inner scale, Rcoh, and that within Rcoh, the cores are ``coherent,'' in that their filling factor is large and they are characterized by a very small, roughly constant, mildly supersonic velocity dispersion. We expect these two papers, by Barranco & Goodman [1] and Goodman, Barranco, Wilner, & Heyer, to appear in the Astrophysical Journal within the coming year. Here, we present a short summary of our results. The interested reader is urged to consult the on-line version of this work at cfa-www.harvard.edu/~agoodman/vel_coh.html [2].

  4. Early Evolution of Prestellar Cores

    NASA Astrophysics Data System (ADS)

    Horedt, G. P.

    2013-08-01

    Prestellar cores are approximated by singular polytropic spheres. Their early evolution is studied analytically with a Bondi-like scheme. The considered approximation is meaningful for polytropic exponents γ between 0 and 6/5, implying radial power-law density profiles between r -1 and r -2.5. Gravitationally unstable Jeans and Bonnor-Ebert masses differ at most by a factor of 3.25. Tidally stable prestellar cores must have a mean density contrast >~ 8 with respect to the external parent cloud medium. The mass-accretion rate relates to the cube of equivalent sound speed, as in Shu's seminal paper. The prestellar masses accreted over 105 years cover the whole stellar mass spectrum; they are derived in simple closed form, depending only on the polytropic equation of state. The stellar masses that can be formed via strict conservation of angular momentum are at most of the order of a brown dwarf.

  5. Accelerator driven sub-critical core

    DOEpatents

    McIntyre, Peter M; Sattarov, Akhdiyor

    2015-03-17

    Systems and methods for operating an accelerator driven sub-critical core. In one embodiment, a fission power generator includes a sub-critical core and a plurality of proton beam generators. Each of the proton beam generators is configured to concurrently provide a proton beam into a different area of the sub-critical core. Each proton beam scatters neutrons within the sub-critical core. The plurality of proton beam generators provides aggregate power to the sub-critical core, via the proton beams, to scatter neutrons sufficient to initiate fission in the sub-critical core.

  6. Sediments at the top of Earth's core.

    PubMed

    Buffett, B A; Garnero, E J; Jeanloz, R

    2000-11-17

    Unusual physical properties at the core-mantle boundary have been inferred from seismic and geodetic observations in recent years. We show how both types of observations can be explained by a layer of silicate sediments, which accumulate at the top of the core as Earth cools. Compaction of the sediments expels most of the liquid iron but leaves behind a small amount of core material, which is entrained in mantle convection and may account for the isotopic signatures of core material in some hot spot plumes. Extraction of light elements from the liquid core also enhances the vigor of convection in the core and may increase the power available to the geodynamo.

  7. Extended core for motor/generator

    DOEpatents

    Shoykhet, Boris A.

    2005-05-10

    An extended stator core in a motor/generator can be utilized to mitigate losses in end regions of the core and a frame of the motor/generator. To mitigate the losses, the stator core can be extended to a length substantially equivalent to or greater than a length of a magnetically active portion in the rotor. Alternatively, a conventional length stator core can be utilized with a shortened magnetically active portion to mitigate losses in the motor/generator. To mitigate the losses in the core caused by stator winding, the core can be extended to a length substantially equivalent or greater than a length of stator winding.

  8. Extended core for motor/generator

    DOEpatents

    Shoykhet, Boris A.

    2006-08-22

    An extended stator core in a motor/generator can be utilized to mitigate losses in end regions of the core and a frame of the motor/generator. To mitigate the losses, the stator core can be extended to a length substantially equivalent to or greater than a length of a magnetically active portion in the rotor. Alternatively, a conventional length stator core can be utilized with a shortened magnetically active portion to mitigate losses in the motor/generator. To mitigate the losses in the core caused by stator winding, the core can be extended to a length substantially equivalent or greater than a length of stator winding.

  9. Laminated electromagnetic pump stator core

    DOEpatents

    Fanning, Alan W.

    1995-01-01

    A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference.

  10. Laminated electromagnetic pump stator core

    DOEpatents

    Fanning, A.W.

    1995-08-08

    A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference. This pump is used in nuclear fission reactors. 19 figs.

  11. Core curriculum illustration: rib fractures.

    PubMed

    Dunham, Gregor M; Perez-Girbes, Alexandre; Linnau, Ken F

    2016-10-26

    This is the 24th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.aseronline.org/curriculum/toc.htm .

  12. Core curriculum illustration: acute pyelonephritis.

    PubMed

    Ramzan, Muhammad Mubashir; Sandstrom, Claire Kalsch

    2016-12-28

    This is the 26th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online please visit the ASER Core Curriculum and Recommendations for Study online at: http://www.aseronline.org/curriculum/toc.htm .

  13. Finding your next core business.

    PubMed

    Zook, Chris

    2007-04-01

    How do you know when your core needs to change? And how do you determine what should replace it? From an in-depth study of 25 companies, the author, a strategy consultant, has discovered that it's possible to measure the vitality of a business's core. If it needs reinvention, he says, the best course is to mine hidden assets. Some of the 25 companies were in deep crisis when they began the process of redefining themselves. But, says Zook, management teams can learn to recognize early signs of erosion. He offers five diagnostic questions with which to evaluate the customers, key sources of differentiation, profit pools, capabilities, and organizational culture of your core business. The next step is strategic regeneration. In four-fifths of the companies Zook examined, a hidden asset was the centerpiece of the new strategy. He provides a map for identifying the hidden assets in your midst, which tend to fall into three categories: undervalued business platforms, untapped insights into customers, and underexploited capabilities. The Swedish company Dometic, for example, was manufacturing small absorption refrigerators for boats and RVs when it discovered a hidden asset: its understanding of, and access to, customers in the RV market. The company took advantage of a boom in that market to refocus on complete systems for live-in vehicles. The Danish company Novozymes, which produced relatively low-tech commodity enzymes such as those used in detergents, realized that its underutilized biochemical capability in genetic and protein engineering was a hidden asset and successfully refocused on creating bioengineered specialty enzymes. Your next core business is not likely to announce itself with fanfare. Use the author's tools to conduct an internal audit of possibilities and pinpoint your new focus.

  14. Dynamics deep from the core

    PubMed Central

    Carbone, F.

    2015-01-01

    In van der Veen et al., [Struct. Dyn. 2, 024302 (2015)], femtosecond and nanosecond electron energy loss spectroscopy of deep core-levels are demonstrated. These results pave the way to the investigation of materials and molecules with combined energy, time, and spatial resolution in a transmission electron microscope. Furthermore, the authors elucidate the role of the electron phonon coupling in the band-gap renormalization that takes place in graphite upon photo-excitation. PMID:26798787

  15. Extralunar dust in apollo cores?

    PubMed

    Barber, D J; Hutcheon, I; Price, P B

    1971-01-29

    Densities of nuclear tracks exceed 10(11) per square centimeter in several percent of the micrometer-size silicate grains from all depths in the 12-and 60-centimeter lunar cores. Either these grains were irradiated in space as extralunar dust or the ratio of iron to hydrogen in low-energy (about 1 million electron volts per nucleon) solar particles is orders of magnitude higher than in the photosphere.

  16. A core dynamo in Vesta?

    NASA Astrophysics Data System (ADS)

    Formisano, M.; Federico, C.; De Angelis, S.; De Sanctis, M. C.; Magni, G.

    2016-05-01

    A recent study of Fu et al. analysed the remaining magnetization in the eucrite meteorite Allan Hills A81001, which mostly likely has been produced during the cooling phase of the life of the asteroid Vesta, arguing that an ancient dynamo in the advective liquid metallic core could be set in. Using petrographic and paleomagnetic arguments, Fu et al. estimated a surface magnetic field of at least 2 μT. In this work, we verify the possibility that an early core dynamo took place in Vesta by analysing four different possible fully differentiated configurations of Vesta, characterized by different chondritic compositions, with the constraints on core size and density provided by Ermakov et al. We only incorporate the thermal convection, by neglecting the effects of the compositional convection, so our results in terms of magnetic Reynolds number and duration of the dynamo can be interpreted as a lower bound. The presence of a magnetic field would make Vesta a peculiar object of the Solar system, a `small-Earth', since it has also a differentiated structure like Earth and the magnetic field has preserved Vesta from the space weathering.

  17. Coring in deep hardrock formations

    SciTech Connect

    Drumheller, D.S.

    1988-08-01

    The United States Department of Energy is involved in a variety of scientific and engineering feasibility studies requiring extensive drilling in hard crystalline rock. In many cases well depths extend from 6000 to 20,000 feet in high-temperature, granitic formations. Examples of such projects are the Hot Dry Rock well system at Fenton Hill, New Mexico and the planned exploratory magma well near Mammoth Lakes, California. In addition to these programs, there is also continuing interest in supporting programs to reduce drilling costs associated with the production of geothermal energy from underground sources such as the Geysers area near San Francisco, California. The overall progression in these efforts is to drill deeper holes in higher temperature, harder formations. In conjunction with this trend is a desire to improve the capability to recover geological information. Spot coring and continuous coring are important elements in this effort. It is the purpose of this report to examine the current methods used to obtain core from deep wells and to suggest projects which will improve existing capabilities. 28 refs., 8 figs., 2 tabs.

  18. Rich-Cores in Networks

    PubMed Central

    Ma, Athen; Mondragón, Raúl J.

    2015-01-01

    A core comprises of a group of central and densely connected nodes which governs the overall behaviour of a network. It is recognised as one of the key meso-scale structures in complex networks. Profiling this meso-scale structure currently relies on a limited number of methods which are often complex and parameter dependent or require a null model. As a result, scalability issues are likely to arise when dealing with very large networks together with the need for subjective adjustment of parameters. The notion of a rich-club describes nodes which are essentially the hub of a network, as they play a dominating role in structural and functional properties. The definition of a rich-club naturally emphasises high degree nodes and divides a network into two subgroups. Here, we develop a method to characterise a rich-core in networks by theoretically coupling the underlying principle of a rich-club with the escape time of a random walker. The method is fast, scalable to large networks and completely parameter free. In particular, we show that the evolution of the core in World Trade and C. elegans networks correspond to responses to historical events and key stages in their physical development, respectively. PMID:25799585

  19. Rich-cores in networks.

    PubMed

    Ma, Athen; Mondragón, Raúl J

    2015-01-01

    A core comprises of a group of central and densely connected nodes which governs the overall behaviour of a network. It is recognised as one of the key meso-scale structures in complex networks. Profiling this meso-scale structure currently relies on a limited number of methods which are often complex and parameter dependent or require a null model. As a result, scalability issues are likely to arise when dealing with very large networks together with the need for subjective adjustment of parameters. The notion of a rich-club describes nodes which are essentially the hub of a network, as they play a dominating role in structural and functional properties. The definition of a rich-club naturally emphasises high degree nodes and divides a network into two subgroups. Here, we develop a method to characterise a rich-core in networks by theoretically coupling the underlying principle of a rich-club with the escape time of a random walker. The method is fast, scalable to large networks and completely parameter free. In particular, we show that the evolution of the core in World Trade and C. elegans networks correspond to responses to historical events and key stages in their physical development, respectively.

  20. An early geodynamo driven by exsolution of mantle components from Earth’s core

    NASA Astrophysics Data System (ADS)

    Badro, James; Siebert, Julien; Nimmo, Francis

    2016-08-01

    Recent palaeomagnetic observations report the existence of a magnetic field on Earth that is at least 3.45 billion years old. Compositional buoyancy caused by inner-core growth is the primary driver of Earth’s present-day geodynamo, but the inner core is too young to explain the existence of a magnetic field before about one billion years ago. Theoretical models propose that the exsolution of magnesium oxide—the major constituent of Earth’s mantle—from the core provided a major source of the energy required to drive an early dynamo, but experimental evidence for the incorporation of mantle components into the core has been lacking. Indeed, terrestrial core formation occurred in the early molten Earth by gravitational segregation of immiscible metal and silicate melts, transporting iron-loving (siderophile) elements from the silicate mantle to the metallic core and leaving rock-loving (lithophile) mantle components behind. Here we present experiments showing that magnesium oxide dissolves in core-forming iron melt at very high temperatures. Using core-formation models, we show that extreme events during Earth’s accretion (such as the Moon-forming giant impact) could have contributed large amounts of magnesium to the early core. As the core subsequently cooled, exsolution of buoyant magnesium oxide would have taken place at the core-mantle boundary, generating a substantial amount of gravitational energy as a result of compositional buoyancy. This amount of energy is comparable to, if not more than, that produced by inner-core growth, resolving the conundrum posed by the existence of an ancient magnetic field prior to the formation of the inner core.

  1. Core Noise: Overview of Upcoming LDI Combustor Test

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.

    2012-01-01

    This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Fixed Wing Project. The presentation covers: the emerging importance of core noise due to turbofan design trends and its relevance to the NASA N+3 noise-reduction goal; the core noise components and the rationale for the current emphasis on combustor noise; and the current and planned research activities in the combustor-noise area. Two NASA-sponsored research programs, with particular emphasis on indirect combustor noise, "Acoustic Database for Core Noise Sources", Honeywell Aerospace (NNC11TA40T) and "Measurement and Modeling of Entropic Noise Sources in a Single-Stage Low-Pressure Turbine", U. Illinois/U. Notre Dame (NNX11AI74A) are briefly described. Recent progress in the development of CMC-based acoustic liners for broadband noise reduction suitable for turbofan-core application is outlined. Combustor-design trends and the potential impacts on combustor acoustics are discussed. A NASA GRC developed nine-point lean-direct-injection (LDI) fuel injector is briefly described. The modification of an upcoming thermo-acoustic instability evaluation of the GRC injector in a combustor rig to also provide acoustic information relevant to community noise is presented. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. The Quiet Performance Research Theme of the Fixed Wing Project aims to develop concepts and technologies to dramatically reduce the perceived community noise attributable to aircraft with minimal impact on weight and performance.

  2. Core Shapes and Orientations of Core-Sérsic Galaxies

    NASA Astrophysics Data System (ADS)

    Dullo, Bililign T.; Graham, Alister W.

    2015-01-01

    The inner and outer shapes and orientations of core-Sérsic galaxies may hold important clues to their formation and evolution. We have therefore measured the central and outer ellipticities and position angles for a sample of 24 core-Sérsic galaxies using archival Hubble Space Telescope (HST) images and data. By selecting galaxies with core-Sérsic break radii Rb —a measure of the size of their partially depleted core—that are >~ 0.''2, we find that the ellipticities and position angles are quite robust against HST seeing. For the bulk of the galaxies, there is a good agreement between the ellipticities and position angles at the break radii and the average outer ellipticities and position angles determined over R e/2 < R < R e, where R e is the spheroids' effective half light radius. However there are some interesting differences. We find a median "inner" ellipticity at Rb of epsilonmed = 0.13 ± 0.01, rounder than the median ellipticity of the "outer" regions epsilonmed = 0.20 ± 0.01, which is thought to reflect the influence of the central supermassive black hole at small radii. In addition, for the first time we find a trend, albeit weak (2σ significance), such that galaxies with larger (stellar deficit-to-supermassive black hole) mass ratios—thought to be a measure of the number of major dry merger events—tend to have rounder inner and outer isophotes, suggesting a connection between the galaxy shapes and their merger histories. We show that this finding is not simply reflecting the well known result that more luminous galaxies are rounder, but it is no doubt related.

  3. CORE SHAPES AND ORIENTATIONS OF CORE-SÉRSIC GALAXIES

    SciTech Connect

    Dullo, Bililign T.; Graham, Alister W.

    2015-01-01

    The inner and outer shapes and orientations of core-Sérsic galaxies may hold important clues to their formation and evolution. We have therefore measured the central and outer ellipticities and position angles for a sample of 24 core-Sérsic galaxies using archival Hubble Space Telescope (HST) images and data. By selecting galaxies with core-Sérsic break radii R{sub b} —a measure of the size of their partially depleted core—that are ≳ 0.''2, we find that the ellipticities and position angles are quite robust against HST seeing. For the bulk of the galaxies, there is a good agreement between the ellipticities and position angles at the break radii and the average outer ellipticities and position angles determined over R {sub e}/2 < R < R {sub e}, where R {sub e} is the spheroids' effective half light radius. However there are some interesting differences. We find a median ''inner'' ellipticity at R{sub b} of ε{sub med} = 0.13 ± 0.01, rounder than the median ellipticity of the ''outer'' regions ε{sub med} = 0.20 ± 0.01, which is thought to reflect the influence of the central supermassive black hole at small radii. In addition, for the first time we find a trend, albeit weak (2σ significance), such that galaxies with larger (stellar deficit-to-supermassive black hole) mass ratios—thought to be a measure of the number of major dry merger events—tend to have rounder inner and outer isophotes, suggesting a connection between the galaxy shapes and their merger histories. We show that this finding is not simply reflecting the well known result that more luminous galaxies are rounder, but it is no doubt related.

  4. Pilates: Build Strength in Your Core Muscles

    MedlinePlus

    ... intimidating, but it's an accessible way to build strength in your core muscles for better posture, balance ... fanatics. It's actually an accessible way to build strength in your core muscles for better posture, balance ...

  5. Investigating the translation of Earth's inner core

    NASA Astrophysics Data System (ADS)

    Day, E. A.; Cormier, V. F.; Geballe, Z. M.; Lasbleis, M.; Youssof, M.; Yue, H.

    2012-12-01

    The Earth's inner core provides unique insights into processes that are occurring deep within our Earth today, as well as processes that occurred in the past. The seismic structure of the inner core is complex, and is dominated by anisotropic and isotropic differences between the Eastern and Western 'hemispheres' of the inner core. Recent geodynamical models suggest that this hemispherical dichotomy can be explained by a fast translation of the inner core. In these models one side of the inner core is freezing, while the other side is melting, leading to the development of different seismic properties on either side of the inner core. A simple translating model of the inner core, however, does not seem to easily explain all of the seismically observed features, including the innermost inner core; the observed sharp lateral gradient in seismic properties between the two hemispheres; and a complex hemispherical and radial dependence of anisotropy, attenuation, and scattering in the uppermost inner core. We explore the compatibility of geodynamic models of a translating inner core with seismic observations. Using a relatively simple set of translation models we map the age of material in the inner core and apply mineral physics models for the evolution of grain size to estimate likely changes in seismic properties throughout the inner core. We then compare these predictions to the observations of seismic studies that target two regions that are highly sensitive to the translation of the inner core: the boundary between the two hemispheres and the regions of freezing and melting at the inner core boundary. To constrain the sharpness of the boundary between the two hemispheres of the inner core we collate a data set of PKiKP-PKIKP, PKP-PKIKP and P‧P‧bc-P‧P‧df differential travel times consisting of paths that sample the core near to the proposed hemisphere boundaries. This combination of body wave data samples a range of depths (and consequently ages) in the

  6. Core Optimization of a Deep-Burn Pebble Bed Reactor

    SciTech Connect

    Brian Boer; Abderrafi M. Ougouag

    2010-06-01

    Achieving a high fuel burnup in the Deep-Burn (DB) pebble bed reactor design, while remaining within the limits for fuel temperature, power peaking and temperature reactivity feedback, is challenging. The high content of Pu and Minor Actinides in the Deep-Burn fuel significantly impacts the thermal neutron energy spectrum as compared to a ’standard’ UO2 fueled core. This can result in power and temperature peaking in the pebble bed core in locally thermalized regions near the graphite reflectors. Furthermore, the interplay of the Pu resonances of the neutron absorption cross sections at low-lying energies can lead to a positive temperature reactivity coefficient for the graphite moderator at certain operating conditions. The DB concept focuses on the destruction of spent fuel transuranics in TRISO coated particle fueled gas-cooled reactors with the aim of a fractional fuel burnup of 60-70% in fissions per initial metal atom (FIMA), using a single-pass, multi in-core fuel (re)cycling scheme. In principle, the DB pebble bed concept employs the same reactor designs as the present low enriched uranium core designs, i.e. the 400 MWth Pebble Bed Modular Reactor (PBMR-400). A Pu and Minor Actinide fueled PBMR-400 design serves as the starting point for a core optimization study. The fuel temperature, power peak, temperature reactivity coefficients, and burnup capabilities of the modified designs are analyzed with the PEBBED code. A code-to-code coupling with the PASTA code allows for the analysis of the TRISO fuel performance for both normal and Loss Of Forced Cooling conditions. An improved core design is sought, maximizing the fuel discharge burnup, while retaining negative temperature reactivity feedback coefficients for the entire temperature range and avoiding high fuel temperatures (fuel failure probabilities).

  7. Rapid planetesimal cooling after core formation: Pallasite meteorites

    NASA Astrophysics Data System (ADS)

    McKibbin, Seann; Ireland, Trevor; O'Neill, Hugh; Holden, Peter; Mallmann, Guilherme; Claeys, Philippe

    2016-04-01

    Pallasite meteorites consist of olivine-metal mixtures and accessory minerals (chromite, sulfide, phosphide, phosphate, phosphoran olivine) and represent core-mantle interaction zones in early differentiated planetesimals. They can be linked to five distinct planetesimals, indicating that they are default differentiation products, but their formation modes (deep, shallow, and impact environments) and age are elusive. Using new trace element, Cr isotope, and previously published datasets, we re-interpret some Main-group pallasites (low-MnO and high-FeO subgroups, e.g. Brenham and Springwater types respectively) as samples of core-mantle reaction zones. These meteorites host rounded olivine and near-solidus phosphate minerals, which record back-reaction of metal and silicate reservoirs during decreasing temperature after core formation and removal of primitive silicate melts. These phosphates form via late oxidation of phosphorus, which is siderophile at high temperature but lithophile at low temperature. Mn-Cr dates this event to before ~2.5 to 4 Myr after Solar System formation (range is model-dependent). Importantly, this is in agreement with Hf-W ages for very early metal-silicate (i.e. core-mantle) separation, but also indicates rapid planetesimal cooling within a few million years. Near-solidus silico-phosphate melts probably formed before most known planetesimal crusts (eucrite and angrite meteorites) and are among the earliest evolved planetary silicates. Similar phosphates in non-Main-Group pallasites from other parent bodies also suggest that core-mantle reaction zones are generic, datable features of differentiation. The absence of near-solidus phosphates in common cluster pallasites suggests that these were quenched from high temperature and are mechanical mixtures, rather than samples of genuine core-mantle boundaries.

  8. Liquid molded hollow cell core composite articles

    NASA Technical Reports Server (NTRS)

    Bernetich, Karl R. (Inventor)

    2005-01-01

    A hollow core composite assembly 10 is provided, including a hollow core base 12 having at least one open core surface 14, a bondable solid film 22 applied to the open core surface 14, at least one dry face ply 30 laid up dry and placed on top of the solid film 22, and a liquid resin 32 applied to the at least one dry face ply 30 and then cured.

  9. Chicxulub Ejecta Impact Trenches And Terminal Impact

    NASA Astrophysics Data System (ADS)

    Page, R. L.

    2013-05-01

    , preparing the Trajectory Section, and locating 12km wide cross sections of the trenches at 4km intervals. Future phases may consist of Telepresence Enabled Exploration of sea floor mapping, seismic mapping, photographic imaging, sea floor samples, core drilling, animated 3D imagery, a documentary film and presentation to the scientific community. GLOBAL SIGNIFICANCE This research will contribute to the knowledge of the phenomenon of the Chicxulub Impact, related impacts and potential identification of its composition. When mapping the 4 asteroids with impact ages of approximately 65 Ma with the trench impact location we find that 3 of the asteroids, Chicxulub, Mexico 150 km diameter; Eagle Butte, Canada 10 km diameter; Vista Alegre, Brazil 9.5 km diameter are in the same orbital plane as the Trench site. This suggests that the smaller asteroids, Eagle Butte and Vista Alegre, separated from the larger Chicxulub Asteroid upon entry and impacted at different locations but on the same orbital plane. The impact of Comet Shoemaker-Levy on Jupiter had 21 impacts over 6 days as the smaller comets separated as it entered the gravitational field of Jupiter. AUTHOR/PRINCIPAL INVESTIGATOR ROBERT L. PAGE, PROF EMERITUS, KANSAS STATE UNIVERSITY JARED PUMPHERY, ILLUSTRATIONS, OCEANOGRAPHIC BATHYRMETRY, MLA, KANSAS STATE UNIVERSITY

  10. H. W. Wilson "Nonbook Materials Core Collection"

    ERIC Educational Resources Information Center

    Harper, Meghan

    2009-01-01

    The "Nonbook Materials Core Collection" is one of H. W. Wilson's new subscription-based electronic core collection development databases. It is a new addition to the five-volume core collection series formerly known as the "Standard Catalog Series." Other titles in this series have long been staples of collection development resources for both…

  11. Rotation and Magnetism of Earth's Inner Core

    PubMed

    Glatzmaier; Roberts

    1996-12-13

    Three-dimensional numerical simulations of the geodynamo suggest that a super- rotation of Earth's solid inner core relative to the mantle is maintained by magnetic coupling between the inner core and an eastward thermal wind in the fluid outer core. This mechanism, which is analogous to a synchronous motor, also plays a fundamental role in the generation of Earth's magnetic field.

  12. Simplifying the ELA Common Core; Demystifying Curriculum

    ERIC Educational Resources Information Center

    Schmoker, Mike; Jago, Carol

    2013-01-01

    The English Language Arts (ELA) Common Core State Standards ([CCSS], 2010) could have a transformational effect on American education. Though the process seems daunting, one can begin immediately integrating the essence of the ELA Common Core in every subject area. This article shows how one could implement the Common Core and create coherent,…

  13. Core Journal Lists: Classic Tool, New Relevance

    ERIC Educational Resources Information Center

    Paynter, Robin A.; Jackson, Rose M.; Mullen, Laura Bowering

    2010-01-01

    Reviews the historical context of core journal lists, current uses in collection assessment, and existing methodologies for creating lists. Outlines two next generation core list projects developing new methodologies and integrating novel information/data sources to improve precision: a national-level core psychology list and the other a local…

  14. Improving Core Strength to Prevent Injury

    ERIC Educational Resources Information Center

    Oliver, Gretchen D.; Adams-Blair, Heather R.

    2010-01-01

    Regardless of the sport or skill, it is essential to have correct biomechanical positioning, or postural control, in order to maximize energy transfer. Correct postural control requires a strong, stable core. A strong and stable core allows one to transfer energy effectively as well as reduce undue stress. An unstable or weak core, on the other…

  15. Common Core: Teaching Optimum Topic Exploration (TOTE)

    ERIC Educational Resources Information Center

    Karge, Belinda Dunnick; Moore, Roxane Kushner

    2015-01-01

    The Common Core has become a household term and yet many educators do not understand what it means. This article explains the historical perspectives of the Common Core and gives guidance to teachers in application of Teaching Optimum Topic Exploration (TOTE) necessary for full implementation of the Common Core State Standards. An effective…

  16. A lunar core dynamo at 3.7 Ga?

    NASA Astrophysics Data System (ADS)

    Shea, E. K.; Weiss, B. P.; Tikoo, S. M.; Gattacceca, J.; Shuster, D. L.; Grove, T. L.; Fuller, M.

    2010-12-01

    The discovery of remnant magnetization in returned Apollo samples and the lunar crust has long suggested that the Moon has a metallic core and once had a core-dynamo magnetic field (Fuller and Cisowski, 1987). However, the association of magnetization with the antipodes of impact basins suggests that meteoroid impacts may also be the source of lunar magnetization (e.g., Hood and Artemieva, 2008). Distinguishing between these two hypotheses is difficult as most lunar samples are poor recorders of paleomagnetic fields (Fuller and Cisowski, 1987; Tikoo et al., 2010). Since impact-generated shock waves can remagnetize low-coercivity (<~30 mT) grains, samples must have high coercivities and show no petrographic evidence for shock (Gattacceca et al., 2009). Recent paleomagnetic analyses of one lunar sample, troctolite 76535, observed a stable NRM blocked up to >200 mT (Garrick-Bethell et al., 2009). The slow cooling timescale of this rock (millions of years) relative the lifetime of impact-produced fields (<1 day maximum) suggests that the moon had a core dynamo at 4.2 Ga. We present a new paleomagnetic study of another high coercivity, unshocked lunar rock, mare basalt 10020. This sample records evidence for lunar magnetism 500 Ma after troctolite 76535. Our results suggest it too has a stable NRM acquired over timescales that are long relative to impact-produced fields. 10020 is a fine-grained, vesicular, ilmenite basalt with a 40Ar/39Ar age of 3.72 ±0.04 Ga that is within error of Rb/Sr crystallization ages of similar composition Apollo 11 basalts (Geiss et al., 1977, Guggisberg et al., 1979). Collinson et al. (1972) and Stephenson et al. 1977 found that a 10020 has one of the most stable NRMs of any studied lunar sample (blocked up to >65 mT). We have now found that two mutually oriented samples of 10020 have a stable (> 65-80 mT) origin-trending unidirectional NRM component. Petrographic analyses of this sample find no evidence for shock such as alteration to

  17. Antiferromagnetic hedgehogs with superconducting cores

    SciTech Connect

    Goldbart, P.M.; Sheehy, D.E.

    1998-09-01

    Excitations of the antiferromagnetic state that resemble antiferromagnetic hedgehogs at large distances but are predominantly superconducting inside a core region are discussed within the context of Zhang{close_quote}s SO(5)-symmetry-based approach to the physics of high-temperature superconducting materials. Nonsingular, in contrast with their hedgehog cousins in pure antiferromagnetism, these texture excitations are what hedgehogs become when the antiferromagnetic order parameter is permitted to {open_quotes}escape{close_quotes} into superconducting directions. The structure of such excitations is determined in a simple setting, and a number of their experimental implications are examined. {copyright} {ital 1998} {ital The American Physical Society}

  18. Antiferromagnetic hedgehogs with superconducting cores

    NASA Astrophysics Data System (ADS)

    Goldbart, Paul M.; Sheehy, Daniel E.

    1998-09-01

    Excitations of the antiferromagnetic state that resemble antiferromagnetic hedgehogs at large distances but are predominantly superconducting inside a core region are discussed within the context of Zhang's SO(5)-symmetry-based approach to the physics of high-temperature superconducting materials. Nonsingular, in contrast with their hedgehog cousins in pure antiferromagnetism, these texture excitations are what hedgehogs become when the antiferromagnetic order parameter is permitted to ``escape'' into superconducting directions. The structure of such excitations is determined in a simple setting, and a number of their experimental implications are examined.

  19. Historical records of trace metals in core sediments from the Lianyungang coastal sea, Jiangsu, China.

    PubMed

    Li, Yu; Li, Hong-Guan

    2017-03-15

    We analyzed element concentrations in cores from the Lianyungang coastal sea to determine depositional trends and geochemical sources of metals. Enrichment factors (EFs) and pollution load index (PLI) were used to assess the enrichment and pollution of metals. Profiles of vertical distributions of the elements reflected different depositional environments in 3 cores. Cores A and C deposited sediments with rich terrestrial elements by rivers, corresponding to mixed-up patterns in the sediment. Meanwhile, core B was mainly deposited in a less undisturbed depositional environment. Correlations and principal component analysis indicated that sediments were influenced by natural and anthropogenic impacts. According to the EFs, most metals showed no significant enrichment and pollution in the core sediments. Lastly, PLI values (<1) of sediments indicated that the Lianyungang coastal sea was a lowly polluted area despite PLI value of metals in average sediment was lower than that in surface sediment.

  20. Moving Away from Exhaustion: How Core Self-Evaluations Influence Academic Burnout

    PubMed Central

    Lian, Penghu; Sun, Yunfeng; Ji, Zhigang; Li, Hanzhong; Peng, Jiaxi

    2014-01-01

    Background Academic burnout refers to students who have low interest, lack of motivation, and tiredness in studying. Studies concerning how to prevent academic burnout are rare. Objective The present study aimed to investigate the impact of core self-evaluations on the academic burnout of university students, and mainly focused on the confirmation of the mediator role of life satisfaction. Methods A total of 470 university students accomplished the core self-evaluation scale, Satisfaction with Life, and academic burnout scale. Results Both core self-evaluations and life satisfaction were significantly correlated with academic burnout. Structural equation modeling indicated that life satisfaction partially mediated the relationship between core self-evaluations and academic burnout. Conclusions Core self-evaluations significantly influence academic burnout and are partially mediated by life satisfaction. PMID:24489857

  1. An evaluation of MPI message rate on hybrid-core processors

    SciTech Connect

    Barrett, Brian W.; Brightwell, Ron; Grant, Ryan; Hammond, Simon D.; Hemmert, K. Scott

    2014-11-01

    Power and energy concerns are motivating chip manufacturers to consider future hybrid-core processor designs that may combine a small number of traditional cores optimized for single-thread performance with a large number of simpler cores optimized for throughput performance. This trend is likely to impact the way in which compute resources for network protocol processing functions are allocated and managed. In particular, the performance of MPI match processing is critical to achieving high message throughput. In this paper, we analyze the ability of simple and more complex cores to perform MPI matching operations for various scenarios in order to gain insight into how MPI implementations for future hybrid-core processors should be designed.

  2. Selection of energy optimized pump concepts for multi core and multi mode erbium doped fiber amplifiers.

    PubMed

    Krummrich, Peter M; Akhtari, Simon

    2014-12-01

    The selection of an appropriate pump concept has a major impact on amplifier cost and power consumption. The energy efficiency of different pump concepts is compared for multi core and multi mode active fibers. In preamplifier stages, pump power density requirements derived from full C-band low noise WDM operation result in superior energy efficiency of direct pumping of individual cores in a multi core fiber with single mode pump lasers compared to cladding pumping with uncooled multi mode lasers. Even better energy efficiency is achieved by direct pumping of the core in multi mode active fibers. Complexity of pump signal combiners for direct pumping of multi core fibers can be reduced by deploying integrated components.

  3. Hybrid Parallelism for Volume Rendering on Large, Multi-core Systems

    SciTech Connect

    Howison, Mark; Bethel, E. Wes; Childs, Hank

    2010-06-14

    This work studies the performance and scalability characteristics of"hybrid" parallel programming and execution as applied to raycasting volume rendering -- a staple visualization algorithm -- on a large, multi-core platform. Historically, the Message Passing Interface (MPI) has become the de-facto standard for parallel programming and execution on modern parallel systems. As the computing industry trends towards multi-core processors, with four- and six-core chips common today and 128-core chips coming soon, we wish to better understand how algorithmic and parallel programming choices impact performance and scalability on large, distributed-memory multi-core systems. Our findings indicate that the hybrid-parallel implementation, at levels of concurrency ranging from 1,728 to 216,000, performs better, uses a smaller absolute memory footprint, and consumes less communication bandwidth than the traditional, MPI-only implementation.

  4. MPI-hybrid Parallelism for Volume Rendering on Large, Multi-core Systems

    SciTech Connect

    Howison, Mark; Bethel, E. Wes; Childs, Hank

    2010-03-20

    This work studies the performance and scalability characteristics of"hybrid'" parallel programming and execution as applied to raycasting volume rendering -- a staple visualization algorithm -- on a large, multi-core platform. Historically, the Message Passing Interface (MPI) has become the de-facto standard for parallel programming and execution on modern parallel systems. As the computing industry trends towards multi-core processors, with four- and six-core chips common today and 128-core chips coming soon, we wish to better understand how algorithmic and parallel programming choices impact performance and scalability on large, distributed-memory multi-core systems. Our findings indicate that the hybrid-parallel implementation, at levels of concurrency ranging from 1,728 to 216,000, performs better, uses a smaller absolute memory footprint, and consumes less communication bandwidth than the traditional, MPI-only implementation.

  5. Pre-hospital core temperature measurement in accidental and therapeutic hypothermia.

    PubMed

    Strapazzon, Giacomo; Procter, Emily; Paal, Peter; Brugger, Hermann

    2014-06-01

    Core temperature (T core) measurement is the only diagnostic tool to accurately assess the severity of hypothermia. International recommendations for management of accidental hypothermia encourage T core measurement for triage, treatment, and transport decisions, but they also recognize that lack of equipment may be a limiting factor, particularly in the field. The aim of this nonsystematic review is to highlight the importance of field measurement of T core and to provide practical guidance for clinicians on pre-hospital temperature measurement in accidental and therapeutic hypothermia. Clinicians should recognize the difference between alternative measurement locations and available thermometers, tailoring their decision to the purpose of the measurement (i.e., intermittent vs. continual measurement), and the impact on management decisions. The importance of T core measurement in therapeutic hypothermia protocols during early cooling and monitoring of target temperature is discussed.

  6. Chronology from sediment cores collected in southwestern Everglades National Park, Florida

    USGS Publications Warehouse

    Bernhardt, C.E.; Wingard, G.L.; Willard, D.A.; Marot, M.E.; Landacre, B.; Holmes, C.W.

    2013-01-01

    Age model data are presented for 10 cores from the southwestern coastal mangrove zone of Everglades National Park, Florida, collected in Common Era (CE) 2004 and 2005 and used for paleoecological analysis. Carbon-14 (14C), lead-210 (210Pb), cesium-137 (137Cs), radium-226 (226Ra), and pollen biostratigraphic information is included, and age models were generated for 6 of the 10 cores. Age reversals and sediment disturbance prevented construction of age models on the remaining four cores. Four cores present a continuous record of the last 50 to 100 years, making them useful for analyzing the impacts caused by changes in water management in south Florida. These cores are Harney River 2A and Harney River 1A, Shark River 2A, and Roberts River.

  7. An evaluation of MPI message rate on hybrid-core processors

    DOE PAGES

    Barrett, Brian W.; Brightwell, Ron; Grant, Ryan; ...

    2014-11-01

    Power and energy concerns are motivating chip manufacturers to consider future hybrid-core processor designs that may combine a small number of traditional cores optimized for single-thread performance with a large number of simpler cores optimized for throughput performance. This trend is likely to impact the way in which compute resources for network protocol processing functions are allocated and managed. In particular, the performance of MPI match processing is critical to achieving high message throughput. In this paper, we analyze the ability of simple and more complex cores to perform MPI matching operations for various scenarios in order to gain insightmore » into how MPI implementations for future hybrid-core processors should be designed.« less

  8. Vortex cores and vortex motion in superconductors with anisotropic Fermi surfaces

    NASA Astrophysics Data System (ADS)

    Galvis, J. A.; Herrera, E.; Guillamón, I.; Vieira, S.; Suderow, H.

    2017-02-01

    Explaning static and dynamic properties of the vortex lattice in anisotropic superconductors requires a careful characterization of vortex cores. The vortex core contains Andreev bound states whose spatial extension depends on the anisotropy of the electronic band-structure and superconducting gap. This might have an impact on the anisotropy of the superconducting properties and on vortex dynamics. Here we briefly summarize basic concepts to understand anisotropic vortex cores and review vortex core imaging experiments. We further discuss moving vortex lattices and the influence of vortex core shape in vortex motion. We find vortex motion in highly tilted magnetic fields. We associate vortex motion to the vortex entry barrier and the screening currents at the surface. We find preferential vortex motion along the main axis of the vortex lattice. After travelling integers of the intervortex distance, we find that vortices move more slowly due to the washboard potential of the vortex lattice.

  9. EFFECTS OF RESISTIVITY ON MAGNETIZED CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Sawai, H.; Suzuki, H.; Yamada, S.; Kotake, K.

    2013-02-10

    We studied the role of turbulent resistivity in the core-collapse of a strongly magnetized massive star, carrying out two-dimensional resistive-MHD simulations. Three cases with different initial strengths of magnetic field and rotation are investigated: (1) a strongly magnetized rotating core, (2) a moderately magnetized rotating core, and (3) a very strongly magnetized non-rotating core. In each case, one ideal-MHD model and two resistive-MHD models are computed. As a result of these computations, each model shows an eruption of matter assisted by magnetic acceleration (and also by centrifugal acceleration in the rotating cases). We found that resistivity attenuates the explosion in cases 1 and 2, while it enhances the explosion in case 3. We also found that in the rotating cases, the main mechanisms for the amplification of a magnetic field in the post-bounce phase are an outward advection of the magnetic field and a twisting of poloidal magnetic field lines by differential rotation, which are somewhat dampened down with the presence of resistivity. Although magnetorotational instability seems to occur in the rotating models, it plays only a minor role in magnetic field amplification. Another impact of resistivity is that on the aspect ratio. In the rotating cases, a large aspect ratio of the ejected matter, >2.5, attained in an ideal-MHD model is reduced to some extent in a resistive model. These results indicate that resistivity possibly plays an important role in the dynamics of strongly magnetized supernovae.

  10. Soft-core processor study for node-based architectures.

    SciTech Connect

    Van Houten, Jonathan Roger; Jarosz, Jason P.; Welch, Benjamin James; Gallegos, Daniel E.; Learn, Mark Walter

    2008-09-01

    Node-based architecture (NBA) designs for future satellite projects hold the promise of decreasing system development time and costs, size, weight, and power and positioning the laboratory to address other emerging mission opportunities quickly. Reconfigurable Field Programmable Gate Array (FPGA) based modules will comprise the core of several of the NBA nodes. Microprocessing capabilities will be necessary with varying degrees of mission-specific performance requirements on these nodes. To enable the flexibility of these reconfigurable nodes, it is advantageous to incorporate the microprocessor into the FPGA itself, either as a hardcore processor built into the FPGA or as a soft-core processor built out of FPGA elements. This document describes the evaluation of three reconfigurable FPGA based processors for use in future NBA systems--two soft cores (MicroBlaze and non-fault-tolerant LEON) and one hard core (PowerPC 405). Two standard performance benchmark applications were developed for each processor. The first, Dhrystone, is a fixed-point operation metric. The second, Whetstone, is a floating-point operation metric. Several trials were run at varying code locations, loop counts, processor speeds, and cache configurations. FPGA resource utilization was recorded for each configuration. Cache configurations impacted the results greatly; for optimal processor efficiency it is necessary to enable caches on the processors. Processor caches carry a penalty; cache error mitigation is necessary when operating in a radiation environment.

  11. Interplay of Neutrino Opacities in Core-collapse Supernova Simulations

    SciTech Connect

    Lentz, Eric J; Mezzacappa, Anthony; Messer, Bronson; Hix, William Raphael; Bruenn, S. W.

    2012-01-01

    We have conducted a series of numerical experiments using spherically symmetric, general relativistic, neutrino radiation hydrodynamics with the code Agile-BOLTZTRAN to examine the effects of including, and improving, the calculation of neutrino opacities on the development of supernova simulations by removing, or replacing, each opacity individually, or removing opacities in groups. We find that during core collapse improvements to electron capture (EC) on nuclei, namely EC on an ensemble of nuclei based on the hybrid model, relative to the simpler independent-particle approximation (IPA) for a mean nucleus, plays the most important role of all tested neutrino opacities. Low-energy neutrinos emitted by nuclear EC preferentially escape during collapse leading to larger deleptonization of the collapsing core, without the energy downscattering via non-isoenergetic scattering (NIS) on electrons required for the models with IPA nuclear EC. During shock breakout the primary influence on the emergent neutrinos arises from NIS on electrons. For the accretion phase NIS on free nucleons and pair emission by $e^+e^-$-annihilation have the largest impact on the neutrino emission and shock evolution. Other opacities evaluated including nucleon-nucleon bremsstrahlung and especially neutrino-positron scattering have little measurable impact on neutrino emission or shock dynamics. Modern treatments of nuclear electron capture, $e^+e^-$-annihilation pair emission, and non-isoenergetic scattering on electrons and free nucleons are critical elements of core-collapse simulations of all dimensionality.

  12. An early geodynamo driven by exsolution of mantle components from Earth's core.

    PubMed

    Badro, James; Siebert, Julien; Nimmo, Francis

    2016-08-18

    Recent palaeomagnetic observations report the existence of a magnetic field on Earth that is at least 3.45 billion years old. Compositional buoyancy caused by inner-core growth is the primary driver of Earth's present-day geodynamo, but the inner core is too young to explain the existence of a magnetic field before about one billion years ago. Theoretical models propose that the exsolution of magnesium oxide--the major constituent of Earth's mantle--from the core provided a major source of the energy required to drive an early dynamo, but experimental evidence for the incorporation of mantle components into the core has been lacking. Indeed, terrestrial core formation occurred in the early molten Earth by gravitational segregation of immiscible metal and silicate melts, transporting iron-loving (siderophile) elements from the silicate mantle to the metallic core and leaving rock-loving (lithophile) mantle components behind. Here we present experiments showing that magnesium oxide dissolves in core-forming iron melt at very high temperatures. Using core-formation models, we show that extreme events during Earth's accretion (such as the Moon-forming giant impact) could have contributed large amounts of magnesium to the early core. As the core subsequently cooled, exsolution of buoyant magnesium oxide would have taken place at the core–mantle boundary, generating a substantial amount of gravitational energy as a result of compositional buoyancy. This amount of energy is comparable to, if not more than, that produced by inner-core growth, resolving the conundrum posed by the existence of an ancient magnetic field prior to the formation of the inner core.

  13. Method for Tracking Core-Contributed Publications

    PubMed Central

    Loomis, Cynthia A.; Curchoe, Carol Lynn

    2012-01-01

    Accurately tracking core-contributed publications is an important and often difficult task. Many core laboratories are supported by programmatic grants (such as Cancer Center Support Grant and Clinical Translational Science Awards) or generate data with instruments funded through S10, Major Research Instrumentation, or other granting mechanisms. Core laboratories provide their research communities with state-of-the-art instrumentation and expertise, elevating research. It is crucial to demonstrate the specific projects that have benefited from core services and expertise. We discuss here the method we developed for tracking core contributed publications. PMID:23204927

  14. Twin-hollow-core optical fibres

    NASA Astrophysics Data System (ADS)

    Argyros, Alexander; Leon-Saval, Sergio G.; van Eijkelenborg, Martijn A.

    2009-05-01

    Twin-hollow-core microstructured optical fibres have been fabricated and characterised for the first time. The fibre cladding structure results in guidance by the inhibited coupling mechanism, in which there is a low overlap between the core modes and surrounding structure. This results in minimal interaction between the modes of each core in the transmission bands of the fibre and hence minimal coupling between the cores. It is shown that light is able to couple between the cores via coupling to cladding struts in the high loss wavelength bands.

  15. Hydrophilic-Core Microcapsules and Their Formation

    NASA Technical Reports Server (NTRS)

    Calle, Luz M. (Inventor); Li, Wenyan (Inventor); Buhrow, Jerry W. (Inventor); Jolley, Scott T. (Inventor)

    2016-01-01

    Hydrophilic-core microcapsules and methods of their formation are provided. A hydrophilic-core microcapsule may include a shell that encapsulates water with the core substance dissolved or dispersed therein. The hydrophilic-core microcapsules may be formed from an emulsion having hydrophilic-phase droplets dispersed in a hydrophobic phase, with shell-forming compound contained in the hydrophilic phase or the hydrophobic phase and the core substance contained in the hydrophilic phase. The shells of the microcapsules may be capable of being broken down in response to being contacted by an alkali, e.g., produced during corrosion, contacting the shell.

  16. Generator stator core vent duct spacer posts

    DOEpatents

    Griffith, John Wesley; Tong, Wei

    2003-06-24

    Generator stator cores are constructed by stacking many layers of magnetic laminations. Ventilation ducts may be inserted between these layers by inserting spacers into the core stack. The ventilation ducts allow for the passage of cooling gas through the core during operation. The spacers or spacer posts are positioned between groups of the magnetic laminations to define the ventilation ducts. The spacer posts are secured with longitudinal axes thereof substantially parallel to the core axis. With this structure, core tightness can be assured while maximizing ventilation duct cross section for gas flow and minimizing magnetic loss in the spacers.

  17. Hydrophobic-Core Microcapsules and Their Formation

    NASA Technical Reports Server (NTRS)

    Calle, Luz M. (Inventor); Li, Wenyan (Inventor); Buhrow, Jerry W. (Inventor); Jolley, Scott T. (Inventor)

    2016-01-01

    Hydrophobic-core microcapsules and methods of their formation are provided. A hydrophobic-core microcapsule may include a shell that encapsulates a hydrophobic substance with a core substance, such as dye, corrosion indicator, corrosion inhibitor, and/or healing agent, dissolved or dispersed therein. The hydrophobic-core microcapsules may be formed from an emulsion having hydrophobic-phase droplets, e.g., containing the core substance and shell-forming compound, dispersed in a hydrophilic phase. The shells of the microcapsules may be capable of being broken down in response to being contacted by an alkali, e.g., produced during corrosion, contacting the shell.

  18. The core legion object model

    SciTech Connect

    Lewis, M.; Grimshaw, A.

    1996-12-31

    The Legion project at the University of Virginia is an architecture for designing and building system services that provide the illusion of a single virtual machine to users, a virtual machine that provides secure shared object and shared name spaces, application adjustable fault-tolerance, improved response time, and greater throughput. Legion targets wide area assemblies of workstations, supercomputers, and parallel supercomputers, Legion tackles problems not solved by existing workstation based parallel processing tools; the system will enable fault-tolerance, wide area parallel processing, inter-operability, heterogeneity, a single global name space, protection, security, efficient scheduling, and comprehensive resource management. This paper describes the core Legion object model, which specifies the composition and functionality of Legion`s core objects-those objects that cooperate to create, locate, manage, and remove objects in the Legion system. The object model facilitates a flexible extensible implementation, provides a single global name space, grants site autonomy to participating organizations, and scales to millions of sites and trillions of objects.

  19. Vortex Cores of Inertial Particles.

    PubMed

    Günther, Tobias; Theisel, Holger

    2014-12-01

    The cores of massless, swirling particle motion are an indicator for vortex-like behavior in vector fields and to this end, a number of coreline extractors have been proposed in the literature. Though, many practical applications go beyond the study of the vector field. Instead, engineers seek to understand the behavior of inertial particles moving therein, for instance in sediment transport, helicopter brownout and pulverized coal combustion. In this paper, we present two strategies for the extraction of the corelines that inertial particles swirl around, which depend on particle density, particle diameter, fluid viscosity and gravity. The first is to deduce the local swirling behavior from the autonomous inertial motion ODE, which eventually reduces to a parallel vectors operation. For the second strategy, we use a particle density estimation to locate inertial attractors. With this, we are able to extract the cores of swirling inertial particle motion for both steady and unsteady 3D vector fields. We demonstrate our techniques in a number of benchmark data sets, and elaborate on the relation to traditional massless corelines.

  20. DIODE STEERED MANGETIC-CORE MEMORY

    DOEpatents

    Melmed, A.S.; Shevlin, R.T.; Laupheimer, R.

    1962-09-18

    A word-arranged magnetic-core memory is designed for use in a digital computer utilizing the reverse or back current property of the semi-conductor diodes to restore the information in the memory after read-out. In order to ob tain a read-out signal from a magnetic core storage unit, it is necessary to change the states of some of the magnetic cores. In order to retain the information in the memory after read-out it is then necessary to provide a means to return the switched cores to their states before read-out. A rewrite driver passes a pulse back through each row of cores in which some switching has taken place. This pulse combines with the reverse current pulses of diodes for each column in which a core is switched during read-out to cause the particular cores to be switched back into their states prior to read-out. (AEC)