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Sample records for a-dlc top layer

  1. 19. EMPTY SEDIMENTATION TANKS. TOP LAYER OF WATER FLOWS OVER ...

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

    19. EMPTY SEDIMENTATION TANKS. TOP LAYER OF WATER FLOWS OVER TRIANGULATED CHANNELS AND OUT THE RAISED DUCTS TO FILTRATION PLANT. MOVEABLE BOARDS ON BOTTOM ASSIST IN REMOVING SLUDGE. VIEW LOOKING NORTHEAST. FILTER CONTROL BUILDING AT REAR. - F. E. Weymouth Filtration Plant, 700 North Moreno Avenue, La Verne, Los Angeles County, CA

  2. Composite structure of plumes in stratus-topped boundary layers

    SciTech Connect

    Moeng, C.H. ); Schumann, U. )

    1991-10-15

    Knowledge of convective plumes within the clear convective boundary layer (CBL) is quite advanced owing to direct measurements, tank experiments, and large-eddy simulation studies. As a result, modeling of the CBL is relatively successful. Progress for the stratus-topped boundary layer (STBL), however, is slow. This study compares the plume structure of the surface-heated CBL with that of the cloud-top-cooled STBL in the hope of extending knowledge of the CBL to the STBL. A conditional sampling technique is applied to the STBL flow fields that are generated through large-eddy simulations, so that the structures of typical updrafts and downdrafts may be derived. For the purpose of comparing the surface-heated CBL and the cloud-top-cooled STBL, an idealized STBL, the compensating updrafts are nearly as strong as the top-cooling-generated downdrafts, and they contribute a significant amount to the heat, moisture, and momentum transports. This differs very much from the CBL, where the compensating downdrafts are much weaker than the surface-heating-generated updrafts and contribute much less to the transports. The mechanism that results in such an asymmetry between the CBL and STBL is examined, and suggestions on how the asymmetry affects the entrainment process are made. 25 refs., 26 figs.

  3. Physical processes within the nocturnal stratus-topped boundary layer

    SciTech Connect

    Moeng, C.H.; Shen, S. ); Randall, D.A. )

    1992-12-15

    Within the stratus-topped boundary layer many physical processes are involved: longwave radiation cooling, entrainment, latent heating, surface heating, solar heating, drizzling, etc. How all processes combine to maintain the turbulence within the stratus-topped boundary layer remains an unsolved problem. The large-eddy simulation technique is used to examine the first four physical processes mentioned. First, the contribution of each physical process to the thermodynamic differences between the updraft and downdraft branches of turbulent circulations is examined through a conditional sampling. Second, these mean thermodynamic differences are shown to express well the vertical distributions of heat and moisture fluxes within stratus-topped boundary layers. These provide a method to validate the process-partitioning technique. (This technique assumes that the net flux profile can be partitioned into different component-flux profiles according to physical processes and that each partitioned component flux is linear in height.) In this paper, the heat and moisture fluxes are process partitioned, and each component flux is found to contribute to the net flux in a way that is consistent with its corresponding process contribution to the mean thermodynamic differences between updrafts and downdrafts. Also, the net flux obtained by summing all component fluxes agrees well with that obtained directly from the large-eddy simulations.

  4. Thermodynamic and radiative structure of stratocumulus-topped boundary layers*

    SciTech Connect

    Ghate, Virendra P.; Miller, Mark A.; Albrecht, Bruce A.; Fairall, Christopher W.

    2015-01-05

    Stratocumulus Topped Boundary Layers (STBL) observed in three different regions with distinctive environments are described in the context of their thermodynamic and radiative properties. Here, the primary data set consisted of 131 soundings from the South East Pacific (SEP), 90 soundings from the island of Graciosa (GRW) in the North Atlantic and 83 soundings from the US Southern Great Plains (SGP). A new technique that preserves the depths of the sub-layers within a STBL is proposed for averaging the profiles of thermodynamic and radiative variables. The STBL was deepest over SEP and had the strongest radiative cooling rates near cloud top among the three locations. Although the radiative cooling rates were comparable over GRW and SGP, the STBL was deeper over GRW compared to that over SGP. On average the STBL inversion was strongest over SEP (11.7 k and -5.43 g kg-1) and weakest over the SGP (6.89 k and -0.41 g kg-1). Significantly larger liquid water path, integrated water vapor, and variability in these two properties was found over GRW and evidence presented suggests that conditions at cloud top may play a lesser role in determining the resident cloud structure over GRW than over SEP. A modal analysis revealed ~26% of the STBL to be well-mixed, ~20% of STBL to be stable and ~30% STBL having a stable layer in-between a surface mixed layer and the cloud layer. Over all the three locations, the STBL was shallowest in well-mixed mode and deepest in the stable mode.

  5. Thermodynamic and radiative structure of stratocumulus-topped boundary layers*

    DOE PAGES

    Ghate, Virendra P.; Miller, Mark A.; Albrecht, Bruce A.; ...

    2015-01-05

    Stratocumulus Topped Boundary Layers (STBL) observed in three different regions with distinctive environments are described in the context of their thermodynamic and radiative properties. Here, the primary data set consisted of 131 soundings from the South East Pacific (SEP), 90 soundings from the island of Graciosa (GRW) in the North Atlantic and 83 soundings from the US Southern Great Plains (SGP). A new technique that preserves the depths of the sub-layers within a STBL is proposed for averaging the profiles of thermodynamic and radiative variables. The STBL was deepest over SEP and had the strongest radiative cooling rates near cloudmore » top among the three locations. Although the radiative cooling rates were comparable over GRW and SGP, the STBL was deeper over GRW compared to that over SGP. On average the STBL inversion was strongest over SEP (11.7 k and -5.43 g kg-1) and weakest over the SGP (6.89 k and -0.41 g kg-1). Significantly larger liquid water path, integrated water vapor, and variability in these two properties was found over GRW and evidence presented suggests that conditions at cloud top may play a lesser role in determining the resident cloud structure over GRW than over SEP. A modal analysis revealed ~26% of the STBL to be well-mixed, ~20% of STBL to be stable and ~30% STBL having a stable layer in-between a surface mixed layer and the cloud layer. Over all the three locations, the STBL was shallowest in well-mixed mode and deepest in the stable mode.« less

  6. Optimizing EDMF parameterization for stratocumulus-topped boundary layer

    NASA Astrophysics Data System (ADS)

    Jones, C. R.; Bretherton, C. S.; Witek, M. L.; Suselj, K.

    2014-12-01

    We present progress in the development of an Eddy Diffusion / Mass Flux (EDMF) turbulence parameterization, with the goal of improving the representation of the cloudy boundary layer in NCEP's Global Forecast System (GFS), as part of a multi-institution Climate Process Team (CPT). Current GFS versions substantially under-predict cloud amount and cloud radiative impact over much of the globe, leading to large biases in the surface and top of atmosphere energy budgets. As part of the effort to correct these biases, the CPT is developing a new EDMF turbulence scheme for GFS, in which local turbulent mixing is represented by an eddy diffusion term while nonlocal shallow convection is represented by a mass flux term. The sum of both contributions provides the total turbulent flux. Our goal is for this scheme to more skillfully simulate cloud radiative properties without negatively impacting other measures of weather forecast skill. One particular challenge faced by an EDMF parameterization is to be able to handle stratocumulus regimes as well as shallow cumulus regimes. In order to isolate the behavior of the proposed EDMF parameterization and aid in its further development, we have implemented the scheme in a portable MATLAB single column model (SCM). We use this SCM framework to optimize the simulation of stratocumulus cloud top entrainment and boundary layer decoupling.

  7. Evaluation of the parameterization for cloud top-down mixing in the boundary layer

    NASA Astrophysics Data System (ADS)

    Lee, Eun-Hee; Hong, Song-You; Dudhia, Jimy

    2015-04-01

    An enhanced turbulent mixing due to radiative cooling at cloud or fog top located in the planetary boundary layer (PBL) is parameterized by adopting the top-down diffusivity profile and the cloud top entrainment. The algorithm is first implemented to YSU PBL scheme to be evaluated for idealized cases and then applied for the regional and global real case simulations. Since the modified algorithm consider the mixing height as near surface cloud top, its enhanced mixing effect appears more distinctly especially for the stabilized nocturnal boundary layer. As a result, in the idealized radiation fog case study, it is found that near-surface air temperature decreases due to both radiative cooling at fog top and boundary layer mixing of the new algorithm. Also, the moisture is diffused more effectively to the above the boundary layer, which leads to the rapid dispersion of the fog in the modified algorithm. As a result, the new algorithm simulates the warm and dried near-surface and the cool and moistened boundary layer top in the following daytime. It is also found that the modified algorithm affects the cloud structure frequently occurring at the ocean boundary layer top in the regional and global simulation results.

  8. Turbulence spectra of the FIRE stratocumulus-topped boundary layers

    NASA Technical Reports Server (NTRS)

    Young, G. S.; Nucciarone, J. J.; Albrecht, Bruce A.

    1990-01-01

    There are at least four physical phenomena which contribute to the FIRE boundary layer turbulence spectra: boundary layer spanning eddies resulting from buoyant and mechanical production of turbulent kinetic energy (the microscale subrange); inertial subrange turbulence which cascades this energy to smaller scales; quasi-two dimensional mesoscale variations; and gravity waves. The relative contributions of these four phenomena to the spectra depend on the altitude of observation and variable involved (vertical velocity, temperature and moisture spectra are discussed). The physical origins of these variations in relative contribution are discussed. As expected from the theory (Kaimal et al., 1976), mixed layer scaling of the spectra (i.e., nondimensionalizing wavelength by Z(sub i) and spectral density by Z(sub i) and the dissipation rates) is successful for the microscale subrange and inertial subrange but not for the mesoscale subrange. The most striking feature of the normalized vertical velocity spectra is the lack of any significant mesoscale contribution. The spectral peak results from buoyant and mechanical production on scales similar to the boundary layer depth. The decrease in spectral density at larger scales results from the suppression of vertical velocity perturbations with large horizontal scales by the shallowness of the atmosphere. The spectral density also decreases towards smaller scales following the well known inertial subrange slope. There is a significant variation in the shape of the normalized spectra with height.

  9. Dynamic Turbulence Modelling in Large-eddy Simulations of the Cloud-topped Atmospheric Boundary Layer

    NASA Technical Reports Server (NTRS)

    Kirkpatrick, M. P.; Mansour, N. N.; Ackerman, A. S.; Stevens, D. E.

    2003-01-01

    The use of large eddy simulation, or LES, to study the atmospheric boundary layer dates back to the early 1970s when Deardor (1972) used a three-dimensional simulation to determine velocity and temperature scales in the convective boundary layer. In 1974 he applied LES to the problem of mixing layer entrainment (Deardor 1974) and in 1980 to the cloud-topped boundary layer (Deardor 1980b). Since that time the LES approach has been applied to atmospheric boundary layer problems by numerous authors. While LES has been shown to be relatively robust for simple cases such as a clear, convective boundary layer (Mason 1989), simulation of the cloud-topped boundary layer has proved more of a challenge. The combination of small length scales and anisotropic turbulence coupled with cloud microphysics and radiation effects places a heavy burden on the turbulence model, especially in the cloud-top region. Consequently, over the past few decades considerable effort has been devoted to developing turbulence models that are better able to parameterize these processes. Much of this work has involved taking parameterizations developed for neutral boundary layers and deriving corrections to account for buoyancy effects associated with the background stratification and local buoyancy sources due to radiative and latent heat transfer within the cloud (see Lilly 1962; Deardor 1980a; Mason 1989; MacVean & Mason 1990, for example). In this paper we hope to contribute to this effort by presenting a number of turbulence models in which the model coefficients are calculated dynamically during the simulation rather than being prescribed a priori.

  10. Influence of the Entrainment Interface Layer on Cloud Microphysical Properties near Stratocumulus Top

    NASA Astrophysics Data System (ADS)

    Chuang, P. Y.; Carman, J. K.; Rossiter, D. L.

    2010-12-01

    Entrainment across the stratocumulus-topped boundary layer is a key process governing the cloud properties and evolution. This process is not well-represented even in high-resolution large-eddy simulations, in part due to the sharp gradients in temperature, buoyancy and (usually) humidity that occur at the top of the boundary layer. In summer 2008, the Physics of Stratocumulus Top (POST) field campaign conduct extensive measurements in the vicinity of cloud top, including the so-called entrainment interface layer or EIL that separates boundary layer and free tropospheric air. Roughly half of the fifteen flights occurred during the day (near solar noon) while the remaining flights occurred during late evening-to-night when solar input was minimal. A wide diversity of EIL properties has been revealed over the course of the campaign. EIL vertical thickness diagnosed using total water varies from fairly thin (~20 m) to very thick (>100 m). The thickness and intensity of the turbulent layer in this interfacial region also varies substantially, with the top of the significantly turbulent region ranging from 10 m to 50 m above cloud top. Shear in the vicinity of cloud top also varied strongly from day-to-day. While almost all cases exhibited strong jumps in potential temperature, there are a number of cases where the jump in total water was very small-to-none, and one case where total water was higher in the free troposphere by 1.4 g/kg. POST thus demonstrates that the cloud-top interfacial region exhibits a rich and diverse range of properties. This study focuses on how this EIL diversity affects the stratocumulus cloud itself. We build on our study of the EIL dynamic and thermodynamic properties to investigate the influence of the EIL on the microphysical properties of the stratocumulus in the vicinity of cloud top. Entrainment of the overlying warmer and (usually) drier air can strongly impact the amount of liquid water as well as the size and concentration of cloud

  11. Aluminum oxide-n-Si field effect inversion layer solar cells with organic top contact

    NASA Astrophysics Data System (ADS)

    Erickson, A. S.; Kedem, N. K.; Haj-Yahia, A. E.; Cahen, D.

    2012-12-01

    We demonstrate a solar cell that uses fixed negative charges formed at the interface of n-Si with Al2O3 to generate strong inversion at the surface of n-Si by electrostatic repulsion. Built-in voltages of up to 755 mV are found at this interface. In order to harness this large built-in voltage, we present a photovoltaic device where the photocurrent generated in this inversion layer is extracted via an inversion layer induced by a high work function transparent organic top contact, deposited on top of a passivating and dipole-inducing molecular monolayer. Results of the effect of the molecular monolayer on device performance yield open-circuit voltages of up to 550 mV for moderately doped Si, demonstrating the effectiveness of this contact structure in removing the Fermi level pinning that has hindered past efforts in developing this type of solar cell with n-type Si.

  12. Perpendicular magnetization of CoFeB on top of an amorphous buffer layer

    NASA Astrophysics Data System (ADS)

    Kim, Dongseok; Jung, K. Y.; Joo, Sungjung; Jang, Youngjae; Hong, Jinki; Lee, B. C.; You, C. Y.; Cho, J. H.; Kim, M. Y.; Rhie, K.

    2015-01-01

    Perpendicular magnetic anisotropy was observed in sputtered FeZr/CoFeB/MgO multilayers. A thin paramagnetic amorphous FeZr layer was used as a buffer layer and perpendicular anisotropy was obtained by annealing the samples without an external magnetic field. The critical CoFeB thickness for perpendicular anisotropy was 1.8 nm; the anisotropy changes from out-of-plane to in-plane as the CoFeB thickness increases beyond this point. Perpendicular anisotropy was also enhanced when a Ta layer was capped on top of the MgO layer. The amorphous buffer provided better perpendicular anisotropy than previously reported Ta buffer, and it may be applied to perpendicular magnetization MRAM devices where good uniformity of tunnel junctions is required.

  13. Layer-Dependent Attentional Processing by Top-down Signals in a Visual Cortical Microcircuit Model

    PubMed Central

    Wagatsuma, Nobuhiko; Potjans, Tobias C.; Diesmann, Markus; Fukai, Tomoki

    2011-01-01

    A vast amount of information about the external world continuously flows into the brain, whereas its capacity to process such information is limited. Attention enables the brain to allocate its resources of information processing to selected sensory inputs for reducing its computational load, and effects of attention have been extensively studied in visual information processing. However, how the microcircuit of the visual cortex processes attentional information from higher areas remains largely unknown. Here, we explore the complex interactions between visual inputs and an attentional signal in a computational model of the visual cortical microcircuit. Our model not only successfully accounts for previous experimental observations of attentional effects on visual neuronal responses, but also predicts contrasting differences in the attentional effects of top-down signals between cortical layers: attention to a preferred stimulus of a column enhances neuronal responses of layers 2/3 and 5, the output stations of cortical microcircuits, whereas attention suppresses neuronal responses of layer 4, the input station of cortical microcircuits. We demonstrate that the specific modulation pattern of layer-4 activity, which emerges from inter-laminar synaptic connections, is crucial for a rapid shift of attention to a currently unattended stimulus. Our results suggest that top-down signals act differently on different layers of the cortical microcircuit. PMID:21779240

  14. [Impact of tillage practices on microbial biomass carbon in top layer of black soils].

    PubMed

    Sun, Bing-jie; Jia, Shu-xia; Zhang, Xiao-ping; Liang, Ai-zhen; Chen, Xue-wen; Zhang, Shi-xiu; Liu, Si-yi; Chen, Sheng-long

    2015-01-01

    A study was conducted on a long-term (13 years) tillage and rotation experiment on black soil in northeast China to determine the effects of tillage, time and soil depth on soil microbial biomass carbon (MBC). Tillage systems included no tillage (NT), ridge tillage (RT) and mould-board plough (MP). Soil sampling was done at 0-5, 5-10 and 10-20 cm depths in June, August and September, 2013, and April, 2014 in the corn phase of corn-soybean rotation plots. MBC content was measured by the chloroform fumigation extraction (CFE) method. The results showed that the MBC content varied with sampling time and soil depth. Soil MBC content was the lowest in April for all three tillage systems, and was highest in June for MP, and highest in August for NT and RT. At each sampling time, tillage system had a significant effect on soil MBC content only in the top 0-5 cm layer. The MBC content showed obvious stratification under NT and RT with a higher MBC content in the top 0-5 cm layer than under MP. The stratification ratios under NT and RT were greatest in September when they were respectively 67.8% and 95.5% greater than under MP. Our results showed that soil MBC contents were greatly affected by the time and soil depth, and were more apparently accumulated in the top layer under NT and RT.

  15. Buoyant production and consumption of turbulence kinetic energy in cloud-topped mixed layers

    NASA Technical Reports Server (NTRS)

    Randall, D. A.

    1984-01-01

    It is pointed out that studies of the entraining planetary boundary layer (PBL) have generally emphasized the role of buoyancy fluxes in driving entrainment. The buoyancy flux is proportional to the rate of conversion of the potential energy of the mean flow into the kinetic energy of the turbulence. It is not unusual for conversion to proceed in both directions simultaneously. This occurs, for instance, in both clear and cloudy convective mixed layers which are capped by inversions. A partitioning of the net conversion into positive parts, generating turbulence kinetic energy (TKE), and negative parts (TKE-consuming), would make it possible to include the positive part in the gross production rate, and closure would be achieved. Three different approaches to partitioning have been proposed. The present investigation is concerned with a comparison of the three partitioning theories. Particular attention is given to the cloud-topped mixed layer because in this case the differences between two partitioning approaches are most apparent.

  16. Dynamics, thermodynamics, radiation, and cloudiness associated with cumulus-topped marine boundary layers

    SciTech Connect

    Ghate, Virendra P.; Miller, Mark

    2016-11-01

    The overall goal of this project was to improve the understanding of marine boundary clouds by using data collected at the Atmospheric Radiation Measurement (ARM) sites, so that they can be better represented in global climate models (GCMs). Marine boundary clouds are observed regularly over the tropical and subtropical oceans. They are an important element of the Earth’s climate system because they have substantial impact on the radiation budget together with the boundary layer moisture, and energy transports. These clouds also have an impact on large-scale precipitation features like the Inter Tropical Convergence Zone (ITCZ). Because these clouds occur at temporal and spatial scales much smaller than those relevant to GCMs, their effects and the associated processes need to be parameterized in GCM simulations aimed at predicting future climate and energy needs. Specifically, this project’s objectives were to (1) characterize the surface turbulent fluxes, boundary layer thermodynamics, radiation field, and cloudiness associated with cumulus-topped marine boundary layers; (2) explore the similarities and differences in cloudiness and boundary layer conditions observed in the tropical and trade-wind regions; and (3) understand similarities and differences by using a simple bulk boundary layer model. In addition to working toward achieving the project’s three objectives, we also worked on understanding the role played by different forcing mechanisms in maintaining turbulence within cloud-topped boundary layers We focused our research on stratocumulus clouds during the first phase of the project, and cumulus clouds during the rest of the project. Below is a brief description of manuscripts published in peer-reviewed journals that describe results from our analyses.

  17. Numerical Investigation of Stratus Cloud Layer Breakup by Cloud Top Instabilities

    NASA Astrophysics Data System (ADS)

    Witting, Patrick Joseph

    1995-01-01

    Large scale atmospheric simulations rely on simple boundary layer models because of computational considerations. Cloud coverage predicted by these boundary layer models is greatly affected by their prediction of the entrainment rate, the rate at which the boundary layer rises. Through direct numerical simulations, this dissertation studies the impact that two cloud top instability mechanisms, cloud top entrainment instability and stratified shear layer instability, have on the entrainment rate. Cloud top entrainment instability, CTEI, is possible when mixtures of dry air from above and cloudy air from below the inversion become negatively buoyant due to evaporative cooling. High resolution two-dimensional simulations with grid spacing as small as 0.25m were used to investigate early CTEI development from small disturbances. Simulations revealed CTEI prefers small wavelengths, has an extended period of exponential growth, and establishes a nearly constant rate of global cloud loss during early nonlinear development which continues into the completely nonlinear phases. The growth rates and cloud loss rates were calculated over a wide range of parameter space. Three-dimensional simulations produced more mixing than their two-dimensional counterparts. Simulations also revealed that shear inhibits CTEI development. Shear often accompanies the jumps of density and moisture across the inversion. If enough shear is present relative to the stable stratification, then the shear layer will roll up into periodic arrays of billows, entraining fluid in the process. These billows are unstable to a pairing mechanism which further spreads the layer by entraining fluid and forming new, larger billows. The pairing process leads to an essentially linear spreading rate until the spreading eventually stops because of increased buoyancy effects. Shear layer simulations address the pairing instability being eventually overwhelmed by buoyancy forces, ending further spreading. The

  18. Low-cost hydrophobic layer as a top plate in two-plate digital microfluidics

    NASA Astrophysics Data System (ADS)

    Tabatabaeipour, Ghiasadin; Hajghassem, Hassan; MohtashamiFar, Mansoor

    2015-07-01

    Digital microfluidics is an emerging technology that is able to manipulate droplets individually. To develop this technology it is needed to use cheaper and more accessible materials for its fabrication. At present, materials commonly used for the hydrophobic layer in these devices are expensive materials that require a legal agreement. In this paper, polydimethylsiloxane (PDMS), which is a common and cheap material in the field of microfluidic, is used as a hydrophobic material for both top and bottom plates of digital microfluidic devices. The droplet cannot be actuated using DC voltage in a surrounding air environment. The reason for the droplet pinning is the high contact angle hysteresis of PDMS surface and considerable thickness of hydrophobic layer on the top plate. In order to overcome this problem, we have exploited a suitable AC voltage (230 Vrms and 8 kHz) as well as changing the surrounding environment to the olive oil. Therefore this paper demonstrates the feasibility of using PDMS as a hydrophobic layer in two-plate digital microfluidics.

  19. Parametric representation of heat and moisture fluxes in cloud-topped mixed layers

    NASA Technical Reports Server (NTRS)

    Penc, Richard S.; Albrecht, Bruce A.

    1987-01-01

    The Betts (1973, 1978) parametrization of heat and moisture fluxes is tested using measurements made in thin, broken, and solid stratocumulus clouds by the NCAR Electra off the California coast in June 1976. The turbulence data are used to determine updraft-downdraft properties, heat and moisture fluxes, spectra, and cospectra. From the convective properties, vertical mass flux profiles are obtained and examined for consistency. A convective scaling which is appropriate for cloud-topped mixed layers is discussed. The results demonstrate the usefulness of a mass flux formulation in modeling applications for cloud conditions varying between solid and broken.

  20. Understanding Near-Surface and In-Cloud Turbulent Fluxes in the Coastal Stratocumulus-Topped Boundary Layers

    DTIC Science & Technology

    2004-10-01

    UNDERSTANDING NEAR-SURFACE AND IN- CLOUD TURBULENT FLUXES IN THE COASTAL STRATOCUMULUS-TOPPED BOUNDARY LAYERS FINAL...Understanding Near-surface and In- cloud Turbulent Fluxes in the Coastal Stratocumulus-topped Boundary 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT...upwelling and stratocumulus cloud contribute significantly in the complexity of the atmospheric flow in the measurements area. Measured surface turbulent

  1. Influence of Subpixel Scale Cloud Top Structure on Reflectances from Overcast Stratiform Cloud Layers

    NASA Technical Reports Server (NTRS)

    Loeb, N. G.; Varnai, Tamas; Winker, David M.

    1998-01-01

    Recent observational studies have shown that satellite retrievals of cloud optical depth based on plane-parallel model theory suffer from systematic biases that depend on viewing geometry, even when observations are restricted to overcast marine stratus layers, arguably the closest to plane parallel in nature. At moderate to low sun elevations, the plane-parallel model significantly overestimates the reflectance dependence on view angle in the forward-scattering direction but shows a similar dependence in the backscattering direction. Theoretical simulations are performed that show that the likely cause for this discrepancy is because the plane-parallel model assumption does not account for subpixel, scale variations in cloud-top height (i.e., "cloud bumps"). Monte Carlo simulation, comparing ID model radiances to radiances from overcast cloud field with 1) cloud-top height variation, but constant cloud volume extinction; 2) flat tops but horizontal variations in cloud volume extinction; and 3) variations in both cloud top height and cloud extinction are performed over a approximately equal to 4 km x 4 km domain (roughly the size of an individual GAC AVHRR pixel). The comparisons show that when cloud-top height variations are included, departures from 1D theory are remarkably similar (qualitatively) to those obtained observationally. In contrast, when clouds are assumed flat and only cloud extinction is variable, reflectance differences are much smaller and do not show any view-angle dependence. When both cloud-top height and cloud extinction variations are included, however, large increases in cloud extinction variability can enhance reflectance difference. The reason 3D-1D reflectance differences are more sensitive to cloud-top height variations in the forward-scattering direction (at moderate to low, sun elevations) is because photons leaving the cloud field in that direction experience fewer scattering events (low-order scattering) and are restricted to the

  2. Mobility enhancement and temperature dependence in top-gated single-layer MoS2

    NASA Astrophysics Data System (ADS)

    Ong, Zhun-Yong; Fischetti, Massimo V.

    2013-10-01

    The deposition of a high-κ oxide overlayer is known to significantly enhance the room-temperature electron mobility in single-layer MoS2 (SLM) but not in single-layer graphene. We give a quantitative account of how this mobility enhancement is due to the nondegeneracy of the two-dimensional electron gas system in SLM at accessible temperatures. Using our charged impurity scattering model [Ong and Fischetti, Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.86.121409 86, 121409 (2012)] and temperature-dependent polarizability, we calculate the charged impurity-limited mobility (μimp) in SLM with and without a high-κ (HfO2) top-gate oxide at different electron densities and temperatures. We find that the mobility enhancement is larger at low electron densities and high temperatures because of finite-temperature screening, thus explaining the enhancement of the mobility observed at room temperature. μimp is shown to decrease significantly with increasing temperature, suggesting that the strong temperature dependence of measured mobilities should not be interpreted as being solely due to inelastic scattering with phonons. We also reproduce the recently seen experimental trend in which the temperature scaling exponent (γ) of μimp∝T-γ is smaller in top-gated SLM than in bare SLM. Finally, we show that ˜37% mobility enhancement can be achieved by reducing the HfO2 thickness from 20 to 2 nm.

  3. Moisture Transport, Lower-Tropospheric Stability, and Decoupling of Cloud-Topped Boundary Layers.

    NASA Astrophysics Data System (ADS)

    Bretherton, Christopher S.; Wyant, Matthew C.

    1997-01-01

    Decoupling during the `Lagrangian' evolution of a cloud-topped boundary layer advected equatorward by the trade winds in an idealized eastern subtropical ocean is studied using a mixed-layer model (MLM). The sea surface temperature is gradually warmed while the free tropospheric sounding remains unchanged, causing the boundary layer to deepen, the surface relative humidity to decrease, and surface latent heat fluxes to increase. Diurnally averaged insolation is used.For entrainment closures in which entrainment rate is related to a large-eddy convective velocity scale w(, the MLM predicts an increasingly prominent layer of negative buoyancy fluxes below cloud base as the sea surface temperature warms. Decoupling of the mixed layer can be inferred when the MLM-predicted negative buoyancy fluxes become too large for the internal circulations to sustain. The authors show that decoupling is mainly driven by an increasing ratio of the surface latent heat flux to the net radiative cooling in the cloud, and derive a decoupling criterion based on this ratio. Other effects such as drizzle, the vertical distribution of radiative cooling in the cloud, and sensible heat fluxes, also affect decoupling but are shown to be less important in typical subtropical boundary layers. A comparison of MLM results with a companion numerical study with a cloud-resolving model shows that the decoupling process is similar and the same decoupling criterion applies. A regional analysis of decoupling using Lagrangian trajectories based on summertime northeast Pacific climatology predicts decoupling throughout the subtropical stratocumulus region except in coastal zones where the boundary layer is under 750 m deep.A `flux-partitioning' entrainment closure, in which the entrainment rate is chosen to maintain a specified ratio of some measure of negative subcloud buoyancy fluxes to positive buoyancy fluxes within the cloud and near the surface, was also considered. By construction, such an MLM

  4. Enhancement of perpendicular coercivity for CoPt top layer in CoPt/AlN multilayer structure

    NASA Astrophysics Data System (ADS)

    Yu, Youxing; Shi, Ji; Nakamura, Yoshio

    2010-07-01

    The magnetic behavior of sputter deposited AlN20 nm/[CoPt2 nm/AlN2 nm]5/CoPt(x) (x as the thickness of the top CoPt layer) multilayer structure has been studied. It has been found that the magnetic anisotropy of the structure strongly depends on thermal annealing. With increasing the annealing temperature, the film changes from the in-plane magnetic anisotropy to the perpendicular anisotropy. Especially, for the top CoPt layer, the perpendicular coercivity increases much rapidly compared with that of the CoPt layers inside the base multilayer, when increasing the annealing temperature to 500 °C or above. The coercivity difference between the top CoPt layer and the base multilayer caused in this way results in an antiparallel alignment state during the magnetization process. The perpendicular magnetization and the coercivity enhancement for the CoPt top layer are correlated with the change in the residual stress inside this layer.

  5. Long-range wetting transparency on top of layered metal-dielectric substrates

    NASA Astrophysics Data System (ADS)

    Noginov, M. A.; Barnakov, Yuri A.; Liberman, Vladimir; Prayakarao, Srujana; Bonner, Carl E.; Narimanov, Evgenii E.

    2016-06-01

    It has been recently shown that scores of physical and chemical phenomena (including spontaneous emission, scattering and Förster energy transfer) can be controlled by nonlocal dielectric environments provided by metamaterials with hyperbolic dispersion and simpler metal/dielectric structures. At this time, we have researched van der Waals interactions and experimentally studied wetting of several metallic, dielectric and composite multilayered substrates. We have found that the wetting angle of water on top of MgF2 is highly sensitive to the thickness of the MgF2 layer and the nature of the underlying substrate that could be positioned as far as ~100 nm beneath the water/MgF2 interface. We refer to this phenomenon as long range wetting transparency. The latter effect cannot be described in terms of the most basic model of dispersion van der Waals-London forces based on pair-wise summation of dipole-dipole interactions across an interface or a gap separating the two media. We infer that the experimentally observed gradual change of the wetting angle with increase of the thickness of the MgF2 layer can possibly be explained by the distance dependence of the Hamaker function (describing the strength of interaction), which originates from retardation of electromagnetic waves at the distances comparable to a wavelength.

  6. Long-range wetting transparency on top of layered metal-dielectric substrates

    PubMed Central

    Noginov, M. A.; Barnakov, Yuri A.; Liberman, Vladimir; Prayakarao, Srujana; Bonner, Carl E.; Narimanov, Evgenii E.

    2016-01-01

    It has been recently shown that scores of physical and chemical phenomena (including spontaneous emission, scattering and Förster energy transfer) can be controlled by nonlocal dielectric environments provided by metamaterials with hyperbolic dispersion and simpler metal/dielectric structures. At this time, we have researched van der Waals interactions and experimentally studied wetting of several metallic, dielectric and composite multilayered substrates. We have found that the wetting angle of water on top of MgF2 is highly sensitive to the thickness of the MgF2 layer and the nature of the underlying substrate that could be positioned as far as ~100 nm beneath the water/MgF2 interface. We refer to this phenomenon as long range wetting transparency. The latter effect cannot be described in terms of the most basic model of dispersion van der Waals-London forces based on pair-wise summation of dipole-dipole interactions across an interface or a gap separating the two media. We infer that the experimentally observed gradual change of the wetting angle with increase of the thickness of the MgF2 layer can possibly be explained by the distance dependence of the Hamaker function (describing the strength of interaction), which originates from retardation of electromagnetic waves at the distances comparable to a wavelength. PMID:27324650

  7. Study of the Impact of Polyanions on the Formation of Lipid Bilayers on Top of Polyelectrolyte Multilayers with Poly(allylamine hydrochloride) as the Top Layer.

    PubMed

    Diamanti, Eleftheria; Andreozzi, Patrizia; Kirby, Christopher; Anguiano, Ramiro; Yate, Luis; Heinz, Hendrik; Ziolo, Ronald F; Donath, Edwin; Moya, Sergio Enrique

    2017-02-09

    The impact of polyanions on the formation of lipid bilayers on top of polyelectrolyte multilayers (PEMs) with poly(allylamine hydrochloride) (PAH) as the top layer is studied for the deposition of vesicles of mixed lipid composition, 50:50 molar ratio of zwitterionic 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and negatively charged 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS). PEMs are assembled with polystyrene sulfonate (PSS), poly(acrylic acid) (PAA), and alginic acid sodium salt (Alg) as polyanions. The assembly of the vesicles on the PEMs is followed by means of the quartz crystal microbalance with dissipation. Fluorescence recovery after photobleaching measurements are applied to evaluate bilayer formation. Whereas a bilayer is formed on top of PAH/PSS multilayers, the vesicles are adsorbed on top of PAH/Alg and PAH/PAA multilayers, remaining unruptured or only partially fused. The influence of the surface composition of the PEM and of the bulk properties of the film are analyzed. The phosphate ions present in phosphate-buffered saline (PBS) play a fundamental role in bilayer formation on top of PAH/PSS as they complex with PAH and render the surface potential close to zero. For PAH/PAA and PAH/Alg, PBS renders the surface negative. X-ray photoelectron spectroscopy shows that the dibasic phosphate ions from PBS complex preferentially with PAH in PAH/PAA and PAH/Alg multilayers, whereas monobasic phosphates complex with PAH in PAH/PSS. An explanation for the absence of bilayer formation on PAH/PAA and PAH/Alg is given on the basis of the different affinities of phosphate ions for PAH in combination with the different polyanions.

  8. Electric field modulation of magnetic anisotropy in perpendicularly magnetized Pt/Co structure with a Pd top layer

    NASA Astrophysics Data System (ADS)

    Hibino, Yuki; Koyama, Tomohiro; Obinata, Aya; Miwa, Kazumoto; Ono, Shimpei; Chiba, Daichi

    2015-11-01

    We investigated the electric field effect on magnetic anisotropy in a perpendicularly magnetized Pt/Co system with a top ultrathin layer of nonmagnetic Pd. By applying an electric field to the surface of the ferromagnetic Pd layer, we observed a clear modulation of the perpendicular magnetic anisotropy of the system. This result shows that the magnetic anisotropy can be modulated by an electric field even when nonmagnetic Pd is inserted at the interface formed by the magnetic layer and insulator. The electric field effect of the proximity-induced moment in Pd might contribute to the anisotropy modulation.

  9. Modification of electronic properties of top-gated graphene devices by ultrathin yttrium-oxide dielectric layers.

    PubMed

    Wang, Lin; Chen, Xiaolong; Wang, Yang; Wu, Zefei; Li, Wei; Han, Yu; Zhang, Mingwei; He, Yuheng; Zhu, Chao; Fung, Kwok Kwong; Wang, Ning

    2013-02-07

    We report the structure characterization and electronic property modification of single layer graphene (SLG) field-effect transistor (FET) devices top-gated using ultrathin Y(2)O(3) as dielectric layers. Based on the Boltzmann transport theory within variant screening, Coulomb scattering is confirmed quantitatively to be dominant in Y(2)O(3)-covered SLG and a very few short-range impurities have been introduced by Y(2)O(3). Both DC transport and AC capacitance measurements carried out at cryogenic temperatures demonstrate that the broadening of Landau levels is mainly due to the additional charged impurities and inhomogeneity of carriers induced by Y(2)O(3) layers.

  10. Qualitative electroless Ni/Au plating considerations for the solder mask on top of sequential build-up layers

    NASA Astrophysics Data System (ADS)

    Siau, Sam; Vervaet, Alfons; Degrendele, Lieven; Baets, Johan De; Calster, Andre Van

    2006-02-01

    Advanced printed circuit boards (PCBs) with sequential build-up (SBU) layers require alternating dielectric and copper layers on top of a core substrate. This can be achieved by lamination of resin coated copper (RCC) or by coating of dielectric polymers followed by copper deposition. The plating of electroless Ni/Au used as a solderability preservative on top of sequential build-up layers is investigated. For this application a solder mask polymer has to be applied in order to separate solder pads. Experiments showed that on parts of the underlying build-up layer exposed to the electroless Ni plating solution electroless Ni can grow. This overplating is caused by the remains of colloidal Pd/Sn catalyst on top of the build-up layer from preceding electroless Cu deposition. At very small features skipping of the plating can also take place. The overplating and skipping phenomena are influenced by a number of parameters, such as the temperature, the concentration of the stabilizer and pH. The dimensions of features on the board and the thickness of the solder-mask polymer also influence skipping. Based on qualitative analyses of the skipping and overplating phenomena rules of thumb for the solder mask design based on the plating conditions are proposed.

  11. Large-eddy Simulation of Stratocumulus-topped Atmospheric Boundary Layers with Dynamic Subgrid-scale Models

    NASA Technical Reports Server (NTRS)

    Senocak, Inane

    2003-01-01

    The objective of the present study is to evaluate the dynamic procedure in LES of stratocumulus topped atmospheric boundary layer and assess the relative importance of subgrid-scale modeling, cloud microphysics and radiation modeling on the predictions. The simulations will also be used to gain insight into the processes leading to cloud top entrainment instability and cloud breakup. In this report we document the governing equations, numerical schemes and physical models that are employed in the Goddard Cumulus Ensemble model (GCEM3D). We also present the subgrid-scale dynamic procedures that have been implemented in the GCEM3D code for the purpose of the present study.

  12. Three-layered supernetwork evolution model and the application for China-world's top 500 enterprises supernetwork

    NASA Astrophysics Data System (ADS)

    Liu, Qiang; Fang, Jin-Qing; Li, Yong

    2014-12-01

    Network of network (NON) or so-called supernetwork extensively exists in the real world. However, so far the definition of NON is not mutually recognized, relevant theory is rather lacking. In order to reveal certain characteristics of NON, we proposed four kinds of three-layered supernetwork evolution models (TLSEM) based on WS small-world and BA scale-free model, and defined two kinds of layer cross-degrees as new measures of cooperative-competition relationship for different layer nodes. The idea and methods of TLSEM are applied to the construction and analysis of China-world's top 500 enterprises supernetworks as a typical empirical example. The analytical results show that the layer cross-degree is better description than other network characteristics, and TLSEM may lay a certain foundation and extend to study more multilevel supernetworks.

  13. Simulating an Evolving Mixed-Phase Cloud-topped Boundary Layer with SHOC (Simplified Higher-Order Closure)

    NASA Astrophysics Data System (ADS)

    Krueger, S. K.; Lesage, A. T.; Bogenschutz, P.

    2014-12-01

    We are using a cloud-resolving model, SAM (System for Atmospheric Modeling) to examine the sensitivity of our simulations of an evolving mixed-phase cloud-topped boundary layer during a cold-air outbreak over the North Atlantic Ocean to the representations of the SGS turbulence and cloudiness and of the microphysics. Our version of SAM includes SHOC (Simplified Higher-Order Closure, Bogenschutz and Krueger 2013) which combines several existing components: A prognostic SGS turbulence kinetic energy (TKE) equation, an assumed double-Gaussian PDF following Golaz et al. (2002), the diagnostic second-moment closure of Redelsperger and Sommeria (1986), the diagnostic closure for the third moment of vertical velocity by Canuto et al. (2001), and a turbulence length scale related to the SGS TKE (Teixeira and Cheinet 2004) and to eddy length scales. Cold-air outbreaks typically produce an evolving cloud-topped boundary layer whose structure is influenced by strong surface fluxes of sensible and latent heat, mixed-phase microphysics, cloud-top radiative cooling, and cloud-top entrainment. By systematically varying the horizontal resolution from 1 to 100 km and comparing the results to a benchmark large-eddy simulation of the case, we will assess the ability of SHOC to represent this type of boundary layer. The image shows the cloud water path from a large-eddy simulation of the CONSTRAIN case. The domain size is 64 km by 64 km. Such simulations are used as benchmarks for coarse-grid simulations that use SHOC.

  14. Transitions of cloud-topped marine boundary layers characterized by AIRS, MODIS, and a large eddy simulation model

    SciTech Connect

    Yue, Qing; Kahn, Brian; Xiao, Heng; Schreier, Mathias; Fetzer, E. J.; Teixeira, J.; Suselj, Kay

    2013-08-16

    Cloud top entrainment instability (CTEI) is a hypothesized positive feedback between entrainment mixing and evaporative cooling near the cloud top. Previous theoretical and numerical modeling studies have shown that the persistence or breakup of marine boundary layer (MBL) clouds may be sensitive to the CTEI parameter. Collocated thermodynamic profile and cloud observations obtained from the Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) instruments are used to quantify the relationship between the CTEI parameter and the cloud-topped MBL transition from stratocumulus to trade cumulus in the northeastern Pacific Ocean. Results derived from AIRS and MODIS are compared with numerical results from the UCLA large eddy simulation (LES) model for both well-mixed and decoupled MBLs. The satellite and model results both demonstrate a clear correlation between the CTEI parameter and MBL cloud fraction. Despite fundamental differences between LES steady state results and the instantaneous snapshot type of observations from satellites, significant correlations for both the instantaneous pixel-scale observations and the long-term averaged spatial patterns between the CTEI parameter and MBL cloud fraction are found from the satellite observations and are consistent with LES results. This suggests the potential of using AIRS and MODIS to quantify global and temporal characteristics of the cloud-topped MBL transition.

  15. Selective Activation of the Deep Layers of the Human Primary Visual Cortex by Top-Down Feedback.

    PubMed

    Kok, Peter; Bains, Lauren J; van Mourik, Tim; Norris, David G; de Lange, Floris P

    2016-02-08

    In addition to bottom-up input, the visual cortex receives large amounts of feedback from other cortical areas [1-3]. One compelling example of feedback activation of early visual neurons in the absence of bottom-up input occurs during the famous Kanizsa illusion, where a triangular shape is perceived, even in regions of the image where there is no bottom-up visual evidence for it. This illusion increases the firing activity of neurons in the primary visual cortex with a receptive field on the illusory contour [4]. Feedback signals are largely segregated from feedforward signals within each cortical area, with feedforward signals arriving in the middle layer, while top-down feedback avoids the middle layers and predominantly targets deep and superficial layers [1, 2, 5, 6]. Therefore, the feedback-mediated activity increase in V1 during the perception of illusory shapes should lead to a specific laminar activity profile that is distinct from the activity elicited by bottom-up stimulation. Here, we used fMRI at high field (7 T) to empirically test this hypothesis, by probing the cortical response to illusory figures in human V1 at different cortical depths [7-14]. We found that, whereas bottom-up stimulation activated all cortical layers, feedback activity induced by illusory figures led to a selective activation of the deep layers of V1. These results demonstrate the potential for non-invasive recordings of neural activity with laminar specificity in humans and elucidate the role of top-down signals during perceptual processing.

  16. Entrainment Zone Characteristics and Entrainment Rates in Cloud-Topped Boundary Layers from DYCOMS-II

    DTIC Science & Technology

    2012-03-01

    method . With this method , one must measure the mean ascent/descent of the atmosphere at the interface, , alongside the time rate of change of the...using a new method based on turbulence perturbations from high-rate turbulence samplings taken during the Dynamics and Chemistry of Marine...properties and the cloud-top entrainment rates using in situ aircraft measurements . The entrainment zone is defined objectively using a new method based

  17. Exchange coupling in metallic multilayers with a top FeRh layer

    NASA Astrophysics Data System (ADS)

    Yamada, S.; Tanikawa, K.; Hirayama, J.; Kanashima, T.; Taniyama, T.; Hamaya, K.

    2016-05-01

    We study magnetic properties of metallic multilayers with FeRh/ferromagnet interfaces grown by low-temperature molecular beam epitaxy. Room-temperature coercivity of the ferromagnetic layers is significantly enhanced after the growth of FeRh, proving the existence of the exchange coupling between the antiferromagnetic FeRh layer and the ferromagnetic layer. However, exchange bias is not clearly observed probably due to the presence of disordered structures, which result from the lattice strain at the FeRh/ferromagnet interfaces due to the lattice mismatch. We infer that the lattice matched interface between FeRh and ferromagnetic layers is a key parameter for controlling magnetic switching fields in such multilayer systems.

  18. The application of highly doped single-layer graphene as the top electrodes of semitransparent organic solar cells.

    PubMed

    Liu, Zhike; Li, Jinhua; Sun, Zhen-Hua; Tai, Guoan; Lau, Shu-Ping; Yan, Feng

    2012-01-24

    A single-layer graphene film with high conductance and transparency was realized by effective chemical doping. The conductance of single-layer graphene was increased for more than 400% when it was doped with Au nanoparticles and poly(3,4-ethylenedioxythiophene): poly(styrene sulfonic acid). Then semitransparent organic solar cells based on poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) were fabricated with single-layer graphene and indium tin oxide (ITO) as the top and bottom electrodes, respectively. The performance of the devices was optimized by tuning the active layer thickness and doping the single-layer graphene electrodes. The maximum efficiency of 2.7% was observed in the devices with the area of 20 mm(2) illuminated from graphene electrode under the AM1.5 solar simulator. It is notable that all of the devices showed higher efficiency from the graphene than ITO side, which was attributed to the better transmittance of the graphene electrodes. In addition, the influence of the active area of the organic solar cell on its photovoltaic performance was studied. We found that, when the active areas increased from 6 to 50 mm(2), the power conversion efficiencies decreased from 3% to 2.3% because of the increased series resistances and the decreased edge effect of the devices.

  19. The View from the Top: CALIOP Ice Water Content in the Uppermost Layer of Tropical Cyclones

    NASA Technical Reports Server (NTRS)

    Avery, Melody A.; Deng, Min; Garnier, Anne; Heymsfield, Andrew; Pelon, Jacques; Powell, Kathleen A.; Trepte, Charles R.; Vaughan, Mark A.; Winker, David M.; Young, Stuart

    2012-01-01

    NASA's CALIPSO satellite carries both the Cloud and Aerosol Lidar with Orthogonal Polarization (CALIOP) and the Imaging Infrared Radiometer (IIR). The lidar is ideally suited to viewing the very top of tropical cyclones, and the IIR provides critical optical and microphysical information. The lidar and the IIR data work together to understand storm clouds since they are perfectly co-located, and big tropical cyclones provide an excellent complex target for comparing the observations. There is a lot of information from these case studies for understanding both the observations and the tropical cyclones, and we are just beginning to scratch the surface of what can be learned. Many tropical cyclone cloud particle measurements are focused on the middle and lower regions of storms, but characterization of cyclone interaction with the lowermost stratosphere at the upper storm boundary may be important for determining the total momentum and moisture transport budget, and perhaps for predicting storm intensity as well. A surprising amount of cloud ice is to be found at the very top of these big storms.

  20. Application of the top specified boundary layer (TSBL) approximation to initial characterization of an inland aquifer mineralization: 2. Seepage of saltwater through semi-confining layers

    USGS Publications Warehouse

    Rubin, H.; Buddemeier, R.W.

    1998-01-01

    This paper presents a generalized basic study that addresses practical needs for an understanding of the major mechanisms involved in the mineralization of groundwater in the Great Bend Prairie aquifer in south- central Kansas. This Quaternary alluvial aquifer and associated surface waters are subject to contamination by saltwater, which in some areas seeps from the deeper Permian bedrock formation into the overlying freshwater aquifer through semiconfining layers. A simplified conceptual model is adopted. It incorporates the freshwater aquifer whose bottom is comprised of a semiconfining layer through which a hydrologically minor but geochemically important saline water discharge seeps into the aquifer. A hierarchy of approximate approaches is considered to analyze the mineralization processes taking place in the aquifer. The recently developed top specified boundary layer (TSBL) approach is very convenient to use for the initial characterization of these processes, and is further adapted to characterization of head-driven seepage through semi-confining layers. TSBL calculations indicate that the seeping saline water may create two distinct new zones in the aquifer: (1) a completely saline zone (CSZ) adjacent to the semiconfining bottom of the aquifer, and (2) a transition zone (TZ) which develops between the CSZ and the freshwater zone. Some possible scenarios associated with the various mineralization patterns are analyzed and discussed.

  1. Optical Properties of Hybrid Inorganic/Organic Thin Film Encapsulation Layers for Flexible Top-Emission Organic Light-Emitting Diodes.

    PubMed

    An, Jae Seok; Jang, Ha Jun; Park, Cheol Young; Youn, Hongseok; Lee, Jong Ho; Heo, Gi-Seok; Choi, Bum Ho; Lee, Choong Hun

    2015-10-01

    Inorganic/organic hybrid thin film encapsulation layers consist of a thin Al2O3 layer together with polymer material. We have investigated optical properties of thin film encapsulation layers for top-emission flexible organic light-emitting diodes. The transmittance of hybrid thin film encapsulation layers and the electroluminescent spectrum of organic light-emitting diodes that were passivated by hybrid organic/inorganic thin film encapsulation layers were also examined as a function of the thickness of inorganic Al203 and monomer layers. The number of interference peaks, their intensity, and their positions in the visible range can be controlled by varying the thickness of inorganic Al2O3 layer. On the other hand, changing the thickness of monomer layer had a negligible effect on the optical properties. We also verified that there is a trade-off between transparency in the visible range and the permeation of water vapor in hybrid thin film encapsulation layers. As the number of dyads decreased, optical transparency improved while the water vapor permeation barrier was degraded. Our study suggests that, in top-emission organic light-emitting diodes, the thickness of each thin film encapsulation layer, in particular that of the inorganic layer, and the number of dyads should be controlled for highly efficient top-emission flexible organic light-emitting diodes.

  2. Near-surface Density Currents Observed in the Southeast Pacific Stratocumulus-topped Marine Boundary Layer

    SciTech Connect

    Wilbanks, Matt C.; Yuter, S. E.; de Szoeke, S.; Brewer, W. A.; Miller, Matthew A.; Hall, Andrew M.; Burleyson, Casey D.

    2015-09-01

    Density currents (i.e. cold pools or outflows) beneath marine stratocumulus clouds are characterized using a 30-d data set of ship-based observations obtained during the 2008 Variability of American Monsoon Systems (VAMOS) Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) in the southeast Pacific. An objective method identifies 71 density current fronts using an air density criterion and isolates each density current’s core (peak density) and tail (dissipating) zone. Compared to front and core zones, most density current tails exhibited weaker density gradients and wind anomalies elongated about the axis of the mean wind. The mean cloud-level advection relative to the surface layer wind (1.9 m s-1) nearly matches the mean density current propagation speed (1.8 m s-1). The similarity in speeds allows drizzle cells to deposit tails in their wakes. Based on high-resolution scanning Doppler lidar data, prefrontal updrafts had a mean intensity of 0.91 m s-1, reached an average altitude of 800 m, and were often surmounted by low-lying shelf clouds not connected to the overlying stratocumulus cloud. Nearly 90% of density currents were identified when C-band radar estimated 30-km diameter areal average rain rates exceeded 1 mm d-1. Rather than peaking when rain rates are highest overnight, density current occurrence peaks between 0600 and 0800 local solar time when enhanced local drizzle co-occurs with shallow subcloud dry and stable layers. The dry layers may contribute to density current formation by enhancing subcloud evaporation of drizzle. Density currents preferentially occur in regions of open cells but also occur in regions of closed cells.

  3. On the Use of Radar Echo from Chaff to Study Entrainment in Stratocumulus Topped Marine Boundary Layers

    NASA Astrophysics Data System (ADS)

    Ghate, V. P.; Albrecht, B. A.; Jonsson, H.; PopStefanija, I.

    2015-12-01

    Marine stratocumulus clouds persist year-round and cover vast areas of the Eastern subtropical oceans. As these clouds have significantly higher albedo than the background sea surface and have warmer cloud top temperatures, they have a net cooling effect on the sea surface and the atmosphere. Hence, these clouds have a huge impact on the Earth's radiation budget and need to be accurately represented in Global Climate Models (GCM) aimed at predicting the future climate and energy needs. The entrainment occurring near the stratocumulus cloud top is one of the key factors influencing the stratocumulus cloud cover and lifetime. In this study, we have used the observations made during the Stratocumulus Entrainment and Precipitation Studies (SEPS) field campaign to quantify and characterize the entrainment in stratocumulus clouds. The data collected by the Compact Frequency Modulated Continuous Wave (CFMCW) W-band Doppler radar, and the in-situ aerosol, cloud, and precipitation size distribution measuring instruments onboard the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS)'s Twin Otter research aircraft formed the basis of this study. We have also used the data collected by the ground-based scanning X-band phased array radar (abbreviated as MWR-05XP) in this study. Finely cut radar chaff fibers corresponding to half the wavelength of the two radars were introduced ~300 m above a uniform stratocumulus cloud layer in a three-line formation on four separate days. The spatial and temporal evolution of the chaff as it dispersed in the free troposphere was tracked for more than two hours by the MWR-05XP that made sector scans every 20 seconds at a 75 m range resolution. The fine-scale evolution of the chaff needles and that of the cloud layer was observed and characterized by the CFMCW radar operating at a 5 m and 3 Hz resolution and by the other instruments onboard the aircraft. The relative dispersion rate of the chaff needles in the free

  4. Large-Eddy Simulations of Strongly Precipitating, Shallow, Stratocumulus-Topped Boundary Layers.

    NASA Astrophysics Data System (ADS)

    Stevens, Bjorn; Cotton, William R.; Feingold, Graham; Moeng, Chin-Hoh

    1998-12-01

    Large-eddy simulations that incorporate a size-resolving representation of cloud water are used to study the effect of heavy drizzle on PBL structure. Simulated surface precipitation rates average about 1 mm day1. Heavily drizzling simulations are compared to nondrizzling simulations under two nocturnal PBL regimes-one primarily driven by buoyancy and the other driven equally by buoyancy and shear. Drizzle implies a net latent heating in the cloud that leads to sharp reductions in both entrainment and the production of turbulent kinetic energy by buoyancy (particularly in downdrafts). Drizzle, which evaporates below cloud base, promotes a cooler and moister subcloud layer that further inhibits deep mixing. The cooling and moistening is in quantitative agreement with some observations and is shown to favor the formation of cumuli rising out of the subcloud layer. The cumuli, which are local in space and time, are responsible for most of the heat and moisture transport. They also appear to generate a larger-scale circulation that differs dramatically from the regularity typically found in nonprecipitating stratocumulus. Time-averaged turbulent fluxes of heat and moisture increase in the presence of precipitation, suggesting that drizzle (and drizzle-induced stratification) should not necessarily be taken as a sign of decoupling. Because drizzle primarily affects the vertical distribution of buoyancy, shear production of turbulent kinetic energy mitigates some of the effects described above. Based on large-eddy simulation the authors hypothesize that shallow, well-mixed, radiatively driven stratocumulus cannot persist in the presence of heavy drizzle. In accord with some simpler models, the simulated case with heavy precipitation promotes a reduction in both liquid-water path and entrainment. However, the simulations suggest that time-integrated cloud fraction may increase as a result of drizzle because thinner precipitating clouds may persist longer if the boundary

  5. Plasma damage-free sputtering of indium tin oxide cathode layers for top-emitting organic light-emitting diodes

    SciTech Connect

    Kim, Han-Ki; Kim, D.-G.; Lee, K.-S.; Huh, M.-S.; Jeong, S.H.; Kim, K.I.; Seong, Tae-Yeon

    2005-05-02

    We report on plasma damage-free sputtering of an indium tin oxide (ITO) cathode layer, which was grown by a mirror shape target sputtering (MSTS) technique, for use in top-emitting organic light-emitting diodes (TOLEDs). It is shown that OLEDs with ITO cathodes deposited by MSTS show much lower leakage current (9.2x10{sup -5} mA/cm{sup 2}) at reverse bias of -6 V as compared to that (1x10{sup -1}-10{sup -2} mA/cm{sup 2} at -6 V) of OLEDs with ITO cathodes grown by conventional dc magnetron sputtering. Based on high-resolution electron microcopy, x-ray diffraction, and scanning electron microscopy results, we describe a possible mechanism by which plasma damage-free ITO films are grown and their application for TOLEDs.

  6. Bidimensional intercalation of Ge between SiC(0001) and a heteroepitaxial graphite top layer

    SciTech Connect

    Kubler, L.; Dentel, D.; Bischoff, J.-L.; Derivaz, M.; Aiet-Mansour, K.; Diani, M.

    2005-09-15

    High temperature annealing of 4H- or 6H-SiC(0001) crystals is well known to desorb Si from the surface and to generate a C-rich (6{radical}3x6{radical}3)R30 deg. (6{radical}3) reconstruction explained as a graphite monolayer in heteroepitaxial registry with the substrate. Ge deposition at room temperature and in the monolayer range on this graphitized reconstruction results in Ge islands. Using a number of surface techniques, we follow subsequent Ge morphology evolutions as a function of isochronal post-annealing treatments at increasing temperatures. In a particular temperature window Ge reacts with the substrate by diffusion under the graphite planes and wets the Si-terminated SiC surface. In spite of this bidimensional insertion of a Ge layer, the epitaxial relationship between the SiC substrate and the graphite is maintained as shown by very clear graphite-(1x1) LEED or RHEED patterns. They denote extended and well-ordered graphite planes at the surface of a graphite/Ge/SiC heterostructure. XPS analyses reveal a complete passivation of the intercalated Ge layer against oxidation by the overlying graphite sheets. Moreover, drastic spectroscopic changes on the bulk-SiC Si 2p and C 1s core levels are observed, depending on whether graphite(6{radical}3)/SiC or graphite(1x1)/Ge/SiC terminations are analyzed. In the latter case, the observed core level splitting of the bulk components is interpreted by a significant upward band bending ({approx}1.2 eV) of the n-doped SiC, making this second interface to act as a Schottky barrier. Above 1300 deg. C, a delayed Ge desorption takes place that allows the graphite sheets to re-form in their initial 6{radical}3 form, i.e., without Ge and with flatter bands.

  7. Arctic low-level boundary layer clouds: in-situ measurements and simulations of mono- and bimodal supercooled droplet size distributions at the cloud top layer

    NASA Astrophysics Data System (ADS)

    Klingebiel, M.; de Lozar, A.; Molleker, S.; Weigel, R.; Roth, A.; Schmidt, L.; Meyer, J.; Ehrlich, A.; Neuber, R.; Wendisch, M.; Borrmann, S.

    2014-06-01

    Aircraft borne optical in-situ size distribution measurements were performed within Arctic boundary layer clouds, with a special emphasis on the cloud top layer, during the VERtical Distribution of Ice in Arctic Clouds (VERDI) campaign. The observations were carried out within a joint research activity of seven German institutes to investigate Arctic boundary layer-, mixed-phase clouds in April and May 2012. An instrumented Basler BT-67 research aircraft operated out of Inuvik over the Mackenzie River delta and the Beaufort Sea in the Northwest Territories of Canada. Besides the cloud particle and hydrometeor size spectrometers the aircraft was equipped with instrumentation for aerosol, radiation and other parameters. Inside the cloud, droplet size distributions with monomodal shapes were observed for predominantly liquid-phase Arctic stratocumulus. With increasing altitude inside the cloud the droplet mean diameters grew from 10 μm to 20 μm. In the upper transition zone (i.e. adjacent to the cloud-free air aloft) changes from monomodal to bimodal droplet size distributions were observed. It is shown that droplets of both modes co-exist in the same (small) air volume and the bimodal shape of the measured size distributions cannot be explained as an observational artifact caused by accumulating two droplet populations from different air volumes. The formation of a second size mode can be explained by (a) entrainment and activation/condensation of fresh aerosol particles, or (b) by differential evaporation processes occurring with cloud droplets engulfed in different eddies. Activation of entrained particles seemed a viable possibility as a layer of dry Arctic enhanced background aerosol was detected directly above the stratus cloud might form a second mode of small cloud droplets. However, theoretical considerations and a model simulation revealed that, instead, turbulent mixing and evaporation of larger droplets most likely are the main reasons for the formation

  8. Arctic low-level boundary layer clouds: in situ measurements and simulations of mono- and bimodal supercooled droplet size distributions at the top layer of liquid phase clouds

    NASA Astrophysics Data System (ADS)

    Klingebiel, M.; de Lozar, A.; Molleker, S.; Weigel, R.; Roth, A.; Schmidt, L.; Meyer, J.; Ehrlich, A.; Neuber, R.; Wendisch, M.; Borrmann, S.

    2015-01-01

    Aircraft borne optical in situ size distribution measurements were performed within Arctic boundary layer clouds with a special emphasis on the cloud top layer during the VERtical Distribution of Ice in Arctic clouds (VERDI) campaign in April and May 2012. An instrumented Basler BT-67 research aircraft operated out of Inuvik over the Mackenzie River delta and the Beaufort Sea in the Northwest Territories of Canada. Besides the cloud particle and hydrometeor size spectrometers the aircraft was equipped with instrumentation for aerosol, radiation and other parameters. Inside the cloud, droplet size distributions with monomodal shapes were observed for predominantly liquid-phase Arctic stratocumulus. With increasing altitude inside the cloud the droplet mean diameters grew from 10 to 20 μm. In the upper transition zone (i.e., adjacent to the cloud-free air aloft) changes from monomodal to bimodal droplet size distributions (Mode 1 with 20 μm and Mode 2 with 10 μm diameter) were observed. It is shown that droplets of both modes co-exist in the same (small) air volume and the bimodal shape of the measured size distributions cannot be explained as an observational artifact caused by accumulating data point populations from different air volumes. The formation of the second size mode can be explained by (a) entrainment and activation/condensation of fresh aerosol particles, or (b) by differential evaporation processes occurring with cloud droplets engulfed in different eddies. Activation of entrained particles seemed a viable possibility as a layer of dry Arctic enhanced background aerosol (which was detected directly above the stratus cloud) might form a second mode of small cloud droplets. However, theoretical considerations and model calculations (adopting direct numerical simulation, DNS) revealed that, instead, turbulent mixing and evaporation of larger droplets are the most likely reasons for the formation of the second droplet size mode in the uppermost region

  9. Anomalous output characteristic shift for the n-type lateral diffused metal-oxide-semiconductor transistor with floating P-top layer

    SciTech Connect

    Liu, Siyang; Zhang, Chunwei; Sun, Weifeng; Su, Wei; Wang, Shaorong; Ma, Shulang; Huang, Yu

    2014-04-14

    Anomalous output characteristic shift of the n-type lateral diffused metal-oxide-semiconductor transistor with floating P-top layer is investigated. It shows that the linear drain current has obvious decrease when the output characteristic of fresh device is measured for two consecutive times. The charge pumping experiments demonstrate that the decrease is not from hot-carrier degradation. The reduction of cross section area for the current flowing, which results from the squeezing of the depletion region surrounding the P-top layer, is responsible for the shift. Consequently, the current capability of this special device should be evaluated by the second measured output characteristic.

  10. Pinning properties of Y211 added cold top-seeded YBCO grown on Y2O3 layer

    NASA Astrophysics Data System (ADS)

    Çakır, Bakiye; Duman, Şeyda; Aydıner, Alev

    2016-04-01

    In this study, samples having different composition were prepared with the cold top seeding-melt-growth (TSMG) process by using Nd123 seed. Y2O3 buffer layer was placed to bottom of the pellets consist of Y123: Y211 powder mixtures. Two samples were fabricated in stoichiometric ratios of 1:0 and 1:0.4 labeled as Y0 and Y40, respectively. The Tc onset values of Y0 and Y40 were found to be 93.4 and 93.6 K at 0 T, respectively. The dependence of the effective activation energy U of the flux pinning on the magnetic field and temperature of the sample were determined using the Arrhenius activation energy law from the resistivity curves. The magnetization measurements were performed using a vibrating sample magnetometer (VSM) at 30, 50 and 77 K. The critical current densities (J c) for Y0 and Y40 samples were determined to be 5.1×103 and 3.7×103 A/cm2 at 77 K in 0 T, respectively. The normalized pinning force density versus the reduced field was examined at different temperatures to determine the pinning mechanism.

  11. Effects of V2O5/Au bi-layer electrodes on the top contact Pentacene-based organic thin film transistors

    NASA Astrophysics Data System (ADS)

    Borthakur, Tribeni; Sarma, Ranjit

    2017-01-01

    Top-contact Pentacene-based organic thin film transistors (OTFTs) with a thin layer of Vanadium Pent-oxide between Pentacene and Au layer are fabricated. Here we have found that the devices with V2O5/Au bi-layer source-drain electrode exhibit better field-effect mobility, high on-off ratio, low threshold voltage and low sub-threshold slope than the devices with Au only. The field-effect mobility, current on-off ratio, threshold voltage and sub-threshold slope of V2O5/Au bi-layer OTFT estimated from the device with 15 nm thick V2O5 layer is .77 cm2 v-1 s-1, 7.5×105, -2.9 V and .36 V/decade respectively.

  12. Analysis of pressure-strain and pressure gradient-scalar covariances in cloud-topped boundary layers: A large-eddy simulation study

    NASA Astrophysics Data System (ADS)

    Heinze, Rieke; Mironov, Dmitrii; Raasch, Siegfried

    2016-03-01

    A detailed analysis of the pressure-scrambling terms (i.e., the pressure-strain and pressure gradient-scalar covariances) in the Reynolds-stress and scalar-flux budgets for cloud-topped boundary layers (CTBLs) is performed using high-resolution large-eddy simulation (LES). Two CTBLs are simulated — one with trade wind shallow cumuli, and the other with nocturnal marine stratocumuli. The pressure-scrambling terms are decomposed into contributions due to turbulence-turbulence interactions, mean velocity shear, buoyancy, and Coriolis effects. Commonly used models of these contributions, including a simple linear model most often used in geophysical applications and a more sophisticated two-component-limit (TCL) nonlinear model, are tested against the LES data. The decomposition of the pressure-scrambling terms shows that the turbulence-turbulence and buoyancy contributions are most significant for cloud-topped boundary layers. The Coriolis contribution is negligible. The shear contribution is generally of minor importance inside the cloudy layers, but it is the leading-order contribution near the surface. A comparison of models of the pressure-scrambling terms with the LES data suggests that the more complex TCL model is superior to the simple linear model only for a few contributions. The linear model is able to reproduce the principal features of the pressure-scrambling terms reasonably well. It can be applied in the second-order turbulence modeling of cloud-topped boundary layer flows, provided some uncertainties are tolerated.

  13. In situ atomic layer nitridation on the top and down regions of the amorphous and crystalline high-K gate dielectrics

    NASA Astrophysics Data System (ADS)

    Tsai, Meng-Chen; Lee, Min-Hung; Kuo, Chin-Lung; Lin, Hsin-Chih; Chen, Miin-Jang

    2016-11-01

    Amorphous and crystalline ZrO2 gate dielectrics treated with in situ atomic layer nitridation on the top and down regions (top and down nitridation, abbreviated as TN and DN) were investigated. In a comparison between the as-deposited amorphous DN and TN samples, the DN sample has a lower leakage current density (Jg) of ∼7 × 10-4 A/cm2 with a similar capacitance equivalent thickness (CET) of ∼1.53 nm, attributed to the formation of SiOxNy in the interfacial layer (IL). The post-metallization annealing (PMA) leads to the transformation of ZrO2 from the amorphous to the crystalline tetragonal/cubic phase, resulting in an increment of the dielectric constant. The PMA-treated TN sample exhibits a lower CET of 1.22 nm along with a similar Jg of ∼1.4 × 10-5 A/cm2 as compared with the PMA-treated DN sample, which can be ascribed to the suppression of IL regrowth. The result reveals that the nitrogen engineering in the top and down regions has a significant impact on the electrical characteristics of amorphous and crystalline ZrO2 gate dielectrics, and the nitrogen incorporation at the top of crystalline ZrO2 is an effective approach to scale the CET and Jg, as well as to improve the reliability.

  14. Electrical performance of silicon-on-insulator field-effect transistors with multiple top-gate organic layers in electrolyte solution.

    PubMed

    Khamaisi, Bassam; Vaknin, Oshri; Shaya, Oren; Ashkenasy, Nurit

    2010-08-24

    The utilization of field-effect transistor (FET) devices in biosensing applications have been extensively studied in recent years. Qualitative and quantitative understanding of the contribution of the organic layers constructed on the device gate, and the electrolyte media, on the behavior of the device is thus crucial. In this work we analyze the contribution of different organic layers on the pH sensitivity, threshold voltage, and gain of a silicon-on-insulator based FET device. We further monitor how these properties change as function of the electrolyte screening length. Our results show that in addition to electrostatic effects, changes in the amphoteric nature of the surface also affect the device threshold voltage. These effects were found to be additive for the first (3-aminopropyl)trimethoxysilane linker layer and second biotin receptor layer. For the top streptavidin protein layer, these two effects cancel each other. The number and nature of amphoteric groups on the surface, which changes upon the formation of the layers, was shown also to affect the pH sensitivity of the device. The pH sensitivity reduces with the construction of the first two layers. However, after the formation of the streptavidin protein layer, the protein's multiple charged side chains induce an increase in the sensitivity at low ionic strengths. Furthermore, the organic layers were found to influence the device gain due to their dielectric properties, reducing the gain with the successive construction of each layer. These results demonstrate the multilevel influence of organic layers on the behavior of the FET devices.

  15. Roles of drizzle in a one-dimensional third-order turbulence closure model of the nocturnal stratus-topped marine boundary layer

    NASA Technical Reports Server (NTRS)

    Wang, Shouping; Wang, Qing

    1994-01-01

    This study focuses on the effects of drizzle in a one-dimensional third-order turbulence closure model of the nocturnal stratus-topped marine boundary layer. When the simulated drizzle rate is relatively small (maximum approximately equal to 0.6 mm/day), steady-state solutions are obtained. The boundary layer stabilizes essentially because drizzle causes evaporative cooling of the subcloud layer. This stabilization considerably reduces the buoyancy flux and turbulence kinetic energy below the stratus cloud. Thus, drizzle tends to decouple the cloud from the subcloud layer in the model, as suggested by many observational studies. In addition, the evaporation of drizzle in the subcloud layer creates small scattered clouds, which are likely to represent cumulus clouds, below the solid stratus cloud in the model. The sensitivity experiments show that these scattered clouds help maintain a coupled boundary layer. When the drizzle rate is relatively large (maximum approximately equal to 0.9 mm/day), the response of the model becomes transient with bursts in turbulent fluxes. This phenomenon is related to the formation of the scattered cloud layer below the solid stratus cloud. It appears that the model is inadequate to represent the heat and moisture transport by strong updrafts covering a small fractional area in cumulus convection.

  16. A layered abduction model of perception: Integrating bottom-up and top-down processing in a multi-sense agent

    NASA Technical Reports Server (NTRS)

    Josephson, John R.

    1989-01-01

    A layered-abduction model of perception is presented which unifies bottom-up and top-down processing in a single logical and information-processing framework. The process of interpreting the input from each sense is broken down into discrete layers of interpretation, where at each layer a best explanation hypothesis is formed of the data presented by the layer or layers below, with the help of information available laterally and from above. The formation of this hypothesis is treated as a problem of abductive inference, similar to diagnosis and theory formation. Thus this model brings a knowledge-based problem-solving approach to the analysis of perception, treating perception as a kind of compiled cognition. The bottom-up passing of information from layer to layer defines channels of information flow, which separate and converge in a specific way for any specific sense modality. Multi-modal perception occurs where channels converge from more than one sense. This model has not yet been implemented, though it is based on systems which have been successful in medical and mechanical diagnosis and medical test interpretation.

  17. Application of the top specified boundary layer (TSBL) approximation to initial characterization of an inland aquifer mineralization 1. Direct contact between fresh and saltwater

    USGS Publications Warehouse

    Rubin, H.; Buddemeier, R.W.

    1998-01-01

    This paper presents a basic study in generalized terms that originates from two needs: (1) to understand the major mechanisms involved in the mineralization of groundwater of the Great Bend Prairie aquifer of Kansas by saltwater originating from a deeper Permian bedrock formation, and (2) to develop simple, robust tools that can readily be used for local assessment and management activities in the salt-affected region. A simplified basic conceptual model is adopted, incorporating two horizontal layers of porous medium which come into contact at a specific location within the model domain. The top layer is saturated with freshwater, and the bottom layer is saturated with saltwater. The paper considers various stages of approximation which can be useful for simplified simulation of the build-up of the transition zone (TZ) between the freshwater and the saltwater. The hierarchy of approximate approaches leads to the development of the top specified boundary layer (TSBL) method, which is the major tool used in this study for initial characterization of the development of the TZ. It is shown that the thickness of the TZ is mainly determined by the characteristic dispersivity. The build-up of the TZ is completed after a time period equal to the time needed to advect a fluid particle along the whole extent of the TZ. Potential applications and the effects of natural recharge and pumpage on salinity transport in the domain are discussed and evaluated in the context of demonstrating the practicality of the TSBL approach.

  18. Effect of Mo capping layers thickness on the perpendicular magnetic anisotropy in MgO/CoFeB based top magnetic tunnel junction structure

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Zhu, Kai-Gui; Zhong, Hui-Cai; Zhu, Zheng-Yong; Yu, Tao; Ma, Su-De

    2016-11-01

    A detailed study of the magnetic characterizations of the top structure MgO/CoFeB/Mo is presented. The samples show strong perpendicular magnetic anisotropy (PMA) when the thickness of CoFeB is 0.9 nm and 1.1 nm. The saturation magnetic moment and interface anisotropy constant are 1566 emu/cm3 and 3.75 erg/cm2, respectively. The magnetic dead layer (MDL) is about 0.23 nm in this system. Furthermore, strong capping layer thickness dependence is also observed. The strong PMA of 1.1 nm CoFeB only exists in a Mo cap layer thickness window of 1.2-2 nm. To maintain PMA, the metal layer could not be too thin or thick in these multilayers. The oxidation and diffusion of the metal capping layer should be respectively responsibility for the degradation of PMA in these thin or thick metal capping layer samples. Project supported by the National Fundamental Research Program of China (Grant No. 2011CB921804) and Beijing Key Subject Foundation of Condensed Matter Physics, China (Grant No. 0114023).

  19. Peculiarities of interaction of the pz-, π- electrons and the σp-holes at the top 1-6 layers of HOPG

    NASA Astrophysics Data System (ADS)

    Dementjev, A. P.; Ivanov, K. E.

    2017-03-01

    The present work continues the analysis of results of Dementjev et al. (2015) in order to identify the interlayer interactions of the π-bands. Analysis of the N(E) C KVV Auger spectra of highly-ordered pyro-graphite showed the absence of the electron exchange between the π-bands in 1-6 layers. Since the π-bands are formed by the pz → π transitions, one can suggest that the π-band occupation at each graphene layer is formed by the pz-electrons of this layer. Since the pz electrons belong to the σp-bands, the pz → π transitions in the σp-bands in each of 2-6 graphene layers result in formation of holes H, whose concentration is equal to the concentration of electrons in the π-bands [Hi] tbnd [πi]. This shows the origin of the ambipolar conductivity in graphene. The absence of the electronic interaction between the π-bands allows a suggestion that the interaction between top six graphene layers is due to the van der Waals electrostatic attractive forces. These forces promote the pz → π transitions in each of the 2-6 graphene layers and depend on the number of graphene layers above. The N(E) C KVV Auger spectra allow identification of number (1-6) of graphene layers and the π-band occupation at each of the layer. For the first time a specification of the van der Waals forces in HOPG was done.

  20. Senstitivity analysis of horizontal heat and vapor transfer coefficients for a cloud-topped marine boundary layer during cold-air outbreaks. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Chang, Y. V.

    1986-01-01

    The effects of external parameters on the surface heat and vapor fluxes into the marine atmospheric boundary layer (MABL) during cold-air outbreaks are investigated using the numerical model of Stage and Businger (1981a). These fluxes are nondimensionalized using the horizontal heat (g1) and vapor (g2) transfer coefficient method first suggested by Chou and Atlas (1982) and further formulated by Stage (1983a). In order to simplify the problem, the boundary layer is assumed to be well mixed and horizontally homogeneous, and to have linear shoreline soundings of equivalent potential temperature and mixing ratio. Modifications of initial surface flux estimates, time step limitation, and termination conditions are made to the MABL model to obtain accurate computations. The dependence of g1 and g2 in the cloud topped boundary layer on the external parameters (wind speed, divergence, sea surface temperature, radiative sky temperature, cloud top radiation cooling, and initial shoreline soundings of temperature, and mixing ratio) is studied by a sensitivity analysis, which shows that the uncertainties of horizontal transfer coefficients caused by changes in the parameters are reasonably small.

  1. Influence of layered precursor pellets on the growth and properties of Y-Ba-Cu-O bulk superconductors by top-seeded melt-textured growth

    NASA Astrophysics Data System (ADS)

    Tang, Tian-wei; Wu, Dong-jie; Xu, Ke-Xi

    2016-03-01

    It is well known that a fine and homogeneous distribution of Y2BaCuO5 (Y211) phase particles in single-grain Y-Ba-Cu-O (YBCO) bulk superconductors is essential for improving field-trapping ability. However, the size and concentration of Y211 phase particles in the fully melt-processed superconducting bulk increase significantly with the distance from the seed, which results in the accumulation of Y211 phase particles and the degradation of superconducting properties. In this paper, we report a new method of fabricating single-grain YBCO using layered precursor pellets. Using the top-seeded melt-textured growth process, single-grain YBCO bulk superconductors of about 22 mm in diameter and 9 mm in thickness were fabricated from layered precursor pellets and standard precursor pellets, respectively. The layered precursor pellets consist of precursor powders with 40 mol% Y211 at the top, 30 mol% Y211 in the middle and 20 mol% Y211 at the bottom of the whole pellets, while standard precursor pellets are prepared from precursor powders with only 40 mol% Y211. The growth morphology, microstructure and magnetic flux properties of the layered samples and standard samples were comparatively studied. The results proved that the layered precursor pellets allow a sufficient growth in the c-growth sector and a more uniform distribution of the Y211 phase in the matrix. The distribution of Y211 phase particles is qualitatively explained by the prevalent trapping/pushing theory. The trapped field at 77 K reaches 0.8 T, nearly 29% higher than the standard sample. The present results are very valuable for further improving the properties of YBCO bulk superconductors.

  2. A Model for Particle Microphysics, Turbulent Mixing, and Radiative Transfer in the Stratocumulus-Topped Marine Boundary Layer and Comparisons with Measurements

    NASA Technical Reports Server (NTRS)

    Ackerman, Andrew S.; Toon, Owen B.; Hobbs, Peter V.

    1995-01-01

    A detailed 1D model of the stratocumulus-topped marine boundary layer is described. The model has three coupled components: a microphysics module that resolves the size distributions of aerosols and cloud droplets, a turbulence module that treats vertical mixing between layers, and a multiple wavelength radiative transfer module that calculates radiative heating rates and cloud optical properties. The results of a 12-h model simulation reproduce reasonably well the bulk thermodynamics, microphysical properties, and radiative fluxes measured in an approx. 500-m thick, summertime marine stratocumulus cloud layer by Nicholls. However, in this case, the model predictions of turbulent fluxes between the cloud and subcloud layers exceed the measurements. Results of model simulations are also compared to measurements of a marine stratus layer made under gale conditions and with measurements of a high, thin marine stratocumulus layer. The variations in cloud properties are generally reproduced by the model, although it underpredicts the entrainment of overlying air at cloud top under gale conditions. Sensitivities of the model results are explored. The vertical profile of cloud droplet concentration is sensitive to the lower size cutoff of the droplet size distribution due to the presence of unactivated haze particles in the lower region of the modeled cloud. Increases in total droplet concentrations do not always produce less drizzle and more cloud water in the model. The radius of the mean droplet volume does not correlate consistently with drizzle, but the effective droplet radius does. The greatest impacts on cloud properties predicted by the model are produced by halving the width of the size distribution of input condensation nuclei and by omitting the effect of cloud-top radiative cooling on the condensational growth of cloud droplets. The omission of infrared scattering produces noticeable changes in cloud properties. The collection efficiencies for droplets less

  3. A Model for Particle Microphysics,Turbulent Mixing, and Radiative Transfer in the Stratocumulus-Topped Marine Boundary Layer and Comparisons with Measurements

    NASA Technical Reports Server (NTRS)

    Ackerman, Andrew S.; Toon, Owen B.; Hobbs, Peter V.

    1995-01-01

    A detailed 1D model of the stratocumulus-topped marine boundary layer is described. The model has three coupled components: a microphysics module that resolves the size distributions of aerosols and cloud droplets, a turbulence module that treats vertical mixing between layers, and a multiple wavelength radiative transfer module that calculates radiative heating rates and cloud optical properties. The results of a 12-h model simulation reproduce reasonably well the bulk thermodynamics, microphysical properties, and radiative fluxes measured in an approx. 500-m thick, summertime marine stratocumulus cloud layer by Nicholls. However, in this case, the model predictions of turbulent fluxes between the cloud and subcloud layers exceed the measurements. Results of model simulations are also compared to measurements of a marine stratus layer made under gate conditions and with measurements of a high, thin marine stratocumulus layer. The variations in cloud properties are generally reproduced by the model, although it underpredicts the entrainment of overlying air at cloud top under gale conditions. Sensitivities of the model results are explored. The vertical profile of cloud droplet concentration is sensitive to the lower size cutoff of the droplet size distribution due to the presence of unactivated haze particles in the lower region of the modeled cloud. Increases in total droplet concentrations do not always produce less drizzle and more cloud water in the model. The radius of the mean droplet volume does not correlate consistently with drizzle, but the effective droplet radius does. The greatest impacts on cloud properties predicted by the model are produced by halving the width of the size distribution of input condensation nuclei and by omitting the effect of cloud-top radiative cooling on the condensational growth of cloud droplets. The omission of infrared scattering produces noticeable changes in cloud properties. The collection efficiencies for droplets less

  4. Effects of flat-topped ion distribution and dust temperature on small amplitude dust-acoustic solitary waves and double layers in dusty plasma

    SciTech Connect

    Alinejad, H.; Mamun, A. A.

    2010-12-15

    The combined effects of the flat-topped ion distribution and dust temperature are incorporated in the study of small but finite amplitude dust-acoustic (DA) solitary waves (SWs) as well double layers (DLs) in an unmagnetized dusty plasma. Due to the flat-trapped ions, our plasma model admits only rarefactive localized structures. It is found that the effects of dust temperature and resonant particles significantly modify the criteria for the existence of DA SWs and DLs, as well as significantly modify their basic properties.

  5. Coordinated Parameterization Development and Large-Eddy Simulation for Marine and Arctic Cloud-Topped Boundary Layers

    NASA Technical Reports Server (NTRS)

    Bretherton, Christopher S.

    2002-01-01

    The goal of this project was to compare observations of marine and arctic boundary layers with: (1) parameterization systems used in climate and weather forecast models; and (2) two and three dimensional eddy resolving (LES) models for turbulent fluid flow. Based on this comparison, we hoped to better understand, predict, and parameterize the boundary layer structure and cloud amount, type, and thickness as functions of large scale conditions that are predicted by global climate models. The principal achievements of the project were as follows: (1) Development of a novel boundary layer parameterization for large-scale models that better represents the physical processes in marine boundary layer clouds; and (2) Comparison of column output from the ECMWF global forecast model with observations from the SHEBA experiment. Overall the forecast model did predict most of the major precipitation events and synoptic variability observed over the year of observation of the SHEBA ice camp.

  6. Coordinated Parameterization Development and Large-Eddy Simulation for Marine and Arctic Cloud-Topped Boundary Layers

    NASA Technical Reports Server (NTRS)

    Bretherton, Christopher S.

    1998-01-01

    The goal of this project was to compare observations of marine and arctic boundary layers with (i) parameterization systems used in climate and weather forecast models, and (ii) two and three dimensional eddy resolving (LES) models for turbulent fluid flow. Based on this comparison, we hoped to better understand, predict, and parameterize the boundary layer structure and cloud amount, type and thickness as functions of large scale conditions that are predicted by global climate models.

  7. Lidar measurements of the atmospheric entrainment zone and the potential temperature jump across the top of the mixed layer

    NASA Technical Reports Server (NTRS)

    Boers, R.; Eloranta, E. W.

    1986-01-01

    Lidar data of the atmospheric entrainment zone from six days of clear air convection obtained in central Illinois during July 1979 are presented. A new method to measure the potential temperature jump across the entrainment zone based on only one temperature sounding and continuous lidar measurements of the mixed layer height is developed. An almost linear dependence is found between the normalized entrainment rate and the normalized thickness of the entrainment zone.

  8. Double layer electric fields aiding the production of energetic flat-top distributions and superthermal electrons within magnetic reconnection exhausts

    NASA Astrophysics Data System (ADS)

    Egedal, J.; Daughton, W.; Le, A.; Borg, A. L.

    2015-10-01

    Using a kinetic simulation of magnetic reconnection, it was recently shown that magnetic-field-aligned electric fields (E∥) can be present over large spatial scales in reconnection exhausts. The largest values of E∥ are observed within double layers. The existence of double layers in the Earth's magnetosphere is well documented. In our simulation, their formation is triggered by large parallel streaming of electrons into the reconnection region. These parallel electron fluxes are required for maintaining quasi-neutrality of the reconnection region and increase with decreasing values of the normalized electron pressure upstream of the reconnection region, βe∞=2 μ0ne ∞Te ∞/B∞2 . A threshold (βe∞ < 0.02) is derived for strong double layers to develop. We also document how the electron confinement, provided in part by the structure in E∥, allows sustained energization by perpendicular electric fields (E⊥). The energization is a consequence of the confined electrons' chaotic orbital motion that includes drifts aligned with the reconnection electric field. The level of energization is proportional to the initial particle energy and therefore is enhanced by the initial energy boost of the acceleration potential, e Φ∥=e ∫x∞∥ d l , acquired by electrons entering the region. The mechanism is effective in an extended region of the reconnection exhaust allowing for the generation of superthermal electrons in reconnection scenarios, including those with only a single x-line. An expression for the phase-space distribution of the superthermal electrons is derived, providing an accurate match to the kinetic simulation results. The numerical and analytical results agree with detailed spacecraft observations recorded during reconnection events in the Earth's magnetotail.

  9. Autoionization at the surface of neat water: is the top layer pH neutral, basic, or acidic?

    PubMed

    Vácha, Robert; Buch, Victoria; Milet, Anne; Devlin, J Paul; Jungwirth, Pavel

    2007-09-14

    Autoionization of water which gives rise to its pH is one of the key properties of aqueous systems. Surfaces of water and aqueous electrolyte solutions are traditionally viewed as devoid of inorganic ions; however, recent molecular simulations and spectroscopic experiments show the presence of certain ions including hydronium in the topmost layer. This raises the question of what is the pH (defined using proton concentration in the topmost layer) of the surface of neat water. Microscopic simulations and measurements with atomistic resolution show that the water surface is acidic due to a strong propensity of hydronium (but not of hydroxide) for the surface. In contrast, macroscopic experiments, such as zeta potential and titration measurements, indicate a negatively charged water surface interpreted in terms of preferential adsorption of OH(-). Here we review recent simulations and experiments characterizing autoionization at the surface of liquid water and ice crystals in an attempt to present and discuss in detail, if not fully resolve, this controversy.

  10. Evolution of particle properties and trace gas concentrations at the top of the Mexico City boundary layer

    NASA Astrophysics Data System (ADS)

    Raga, G.; Baumgardner, D.; Grutter, M.; Santos, B. T.; Moya, C. O.; Allan, J.

    2006-12-01

    The Altzomoni ridge is located in the Cortez Pass, in a national park, between the volcanoes of Iztaccihuatl and Popocatepetl, at an altitude of 4010 m, and 60 km to the SE of the center of Mexico City. This region is isolated from local emissions from combustion yet there is a daily incursion of pollution from either the Mexico City basin, when winds are from the west or from the Puebla valley when winds are from the east. This was the motivation for setting up instruments at this site to measure the concentrations of trace gases and the physical, chemical and optical properties of aerosol particles. A 12 m tower was also erected to measure fluxes of momentum, heat, condensation nuclei (CN) and CO2. Measurements were begun during the last week of November, 2005 and continued until early June, 2006. The concentrations of CN, CO2 and CO clearly indicate that the site is in the free troposphere at night and early morning, but the regional boundary layer grows to altitudes above the site every day. Hence, this site is ideal for making observations of atmospheric chemistry at the interface between rural and urban regions. The preliminary analyses have shown that the "free tropospheric" values of CN, particle bound polycyclic aromatic hydrocarbons (PPAH) and black carbon (BC) rarely decrease below 1000 cm-3, 4 ng m-3, 100 ng m-3, respectively, suggesting the presence of a residual layer of contaminants. Nighttime CO and O3 are usually above 0.1 and 0.05 ppm. The CO concentration at the measurement site is a tenth of the Mexico City value and reached its maximum approximately six hours after the maximum in the city center. The maximum O3 in Mexico City and Altzomoni are frequently the same concentration but with no repeatable pattern in the phase differences. The highly linear relationship between BC and CO reflects the removal and dilution processes, i.e. the average ratio between BC and CO in Mexico City is 1000:1 whereas it is 3000:1 in Altzomoni. This relationship

  11. Evolution of trace gas concentrations and the chemical properties of particles at the top of the Mexico City boundary layer.

    NASA Astrophysics Data System (ADS)

    Ochoa, C.; Baumgardner, D.; Grutter, M.

    2007-05-01

    The Altzomoni ridge is located in the Cortez Pass, in a national park, between the volcanoes of Iztaccíhuatl and Popocatépetl, at an altitude of 4010 m, and 60 km to the SE of the center of Mexico City. This region is isolated from local emissions from combustion yet there is a daily incursion of pollution from either the Mexico City basin, when winds are from the west or from the Puebla valley when winds are from the east. This was the motivation for setting up instruments at this site to measure the concentrations of trace gases and the physical, chemical and optical properties of aerosol particles. Measurements were begun during the last week of November, 2005 and continued until early June, 2006. The concentrations of CN, CO2 and CO clearly indicate that the site is in the free troposphere at night and early morning, but the regional boundary layer grows to altitudes above the site every day. Hence, this site is ideal for making observations of atmospheric chemistry at the interface between rural and urban regions. The preliminary analyses have shown that the "free tropospheric" values of CN, particle bound polycyclic aromatic hydrocarbons (PPAH) and black carbon (BC) rarely decrease below 1000 cm-3, 4 ng m-3, 100 ng m-3, respectively, suggesting the presence of a residual layer of contaminants. Nighttime CO and O3 are usually above 0.1 and 0.05 ppm. The CO concentration at the measurement site is a tenth of the Mexico City value and reached its maximum approximately six hours after the maximum in the city center. The maximum O3 in Mexico City and Altzomoni are frequently the same concentration but with no repeatable pattern in the phase differences. The highly linear relationship between BC and CO reflects the removal and dilution processes, i.e. the average ratio between BC and CO in Mexico City is 1000:1 whereas it is 3000:1 in Altzomoni. This relationship also depends on the origin of the boundary layer air, i.e. whether it comes from the east or west

  12. Small amplitude dust ion-acoustic solitary waves and double layers in a dusty plasma with flat-topped electron distribution

    SciTech Connect

    Alinejad, H.; Mamun, A. A.

    2010-12-15

    The properties of small but finite amplitude dust ion-acoustic (DIA) solitary waves (SWs) as well double layers (DLs) in a dusty plasma containing warm adiabatic ions, electrons following flat-topped velocity distribution, and arbitrarily (positively or negatively) charged immobile dust are studied. The effects of ion-temperature, resonant electrons, and dust number density are found to significantly modify the criteria for the existence of the DIA SWs and DLs, as well as significantly modify their basic features. It is also shown that the ion-temperature reduces the possibility for the formation of these localized structures, and that their amplitude decreases (increases) with the increase in the negative (positive) dust number density.

  13. Evolution of anthropogenic pollution at the top of the regional mixed layer in the central Mexico plateau

    NASA Astrophysics Data System (ADS)

    Baumgardner, D.; Grutter, M.; Allan, J.; Ochoa, C.; Rappenglueck, B.; Russell, L. M.; Arnott, P.

    2009-01-01

    The concentrations of gases and properties of aerosol particles have been measured at the mountain site of Altzomoni approximately equidistant from Mexico City, Puebla and Cuernavaca, at an altitude of 4010 m. At this location there is a diurnal transition from local to regional mixed layer air whose properties depend on prevailing winds and larger scale circulation. Three days during March 2006 have been evaluated during which time the synoptic scale air flow was from the east, southeast and southwest. In general the properties of gases and particles were similar when the regional mixed layer (RML) was below the research site, regardless of the direction of flow. When the RML reached the site, the highest concentrations of CO, O3 and aerosol particles were from the east, decreasing as the flow shifted to the southeast then to the southwest. The maximum concentration of condensation nuclei (CN) was greater than 25×10-3 when winds were from the east. The highest mass concentrations of organic matter (OM), sulfate (SO4-), and Nitrate (NO3+ were 80, 4 and 8 μg m-3, at standard temperature and pressure in air from the east. The mass concentration of OM in the RML was greater than 70% of the total mass, regardless of the air mass origin. This compares to less than the 60% that has been reported for Mexico City. At night, the mass fraction of sulfate went up by a factor of ten from the daytime value when air arrived from the east. The relationship between the CO and OM suggests that the majority of the daytime OM is from biomass burning and at night it is from wood burning. Whereas the maximum CO at Altzomoni, 0.35 ppm, was approximately one tenth of the CO measured at the same time in the center of Mexico City, the maximum O3 of 120 ppb was approximately the same as in the city. The maximum nighttime values of O3 was 60 ppb, indicating the presence of residual pollution. From these results we conclude that even though Mexico City is the second most populated city in

  14. Evolution of Anthropogenic Pollution at the Top of the Regional Mixed Layer of the Central Mexico Plateau

    NASA Astrophysics Data System (ADS)

    Baumgardner, D.; Grutter, M.; Allan, J.; Ochoa, C.; Rappenglueck, B.; Russell, L. M.

    2009-04-01

    The concentrations of gases and properties of aerosol particles have been measured at the mountain site of Altzomoni approximately equidistant from Mexico City, Puebla and Cuernavaca, at an altitude of 4010 m. At this location there is a diurnal transition from local to regional mixed layer air whose properties depend on prevailing winds and larger scale circulation. Three days during March, 2006 have been evaluated during which time the synoptic scale air flow was from the east, southeast and southwest. In general the properties of gases and particles were similar when the regional mixed layer (RML) was below the research site, regardless of the direction of flow. When the RML reached the site, the highest concentrations of CO, O3 and aerosol particles were from the east, decreasing as the flow shifted to the southeast then to the southwest. The maximum concentration of condensation nuclei (CN) was greater than 25,000 cm-3 when winds were from the east. The highest mass concentrations of organic matter (OM), sulfate (SO4--), and Nitrate (NO3+) were 80, 4 and 8 μg m-3, at standard temperature and pressure in air from the east. The mass concentration of OM in the RML was greater than 70% of the total mass, regardless of the air mass origin. This compares to less than the 60% that has been reported for Mexico City. At night, the mass fraction of sulfate went up by a factor of ten from the daytime value when air arrived from the east. The relationship between the CO and OM suggests that the majority of the daytime OM is from biomass burning and at night it is from wood burning. Whereas the maximum CO at Altzomoni, 0.35 ppm, was approximately one tenth of the CO measured at the same time in the center of Mexico City, the maximum O3 of 120 ppb was approximately the same as in the city. The nighttime values of O3 was 60 ppb, indicating the presence of residual pollution. From these results we conclude that even though Mexico City is the second most populated city in the

  15. Prediction of Hexaconazole Concentration in the Top Most Layer of Oil Palm Plantation Soil Using Exploratory Data Analysis (EDA)

    PubMed Central

    Maznah, Zainol; Halimah, Muhamad; Shitan, Mahendran; Kumar Karmokar, Provash; Najwa, Sulaiman

    2017-01-01

    Ganoderma boninense is a fungus that can affect oil palm trees and cause a serious disease called the basal stem root (BSR). This disease causes the death of more than 80% of oil palm trees midway through their economic life and hexaconazole is one of the particular fungicides that can control this fungus. Hexaconazole can be applied by the soil drenching method and it will be of interest to know the concentration of the residue in the soil after treatment with respect to time. Hence, a field study was conducted in order to determine the actual concentration of hexaconazole in soil. In the present paper, a new approach that can be used to predict the concentration of pesticides in the soil is proposed. The statistical analysis revealed that the Exploratory Data Analysis (EDA) techniques would be appropriate in this study. The EDA techniques were used to fit a robust resistant model and predict the concentration of the residue in the topmost layer of the soil. PMID:28060816

  16. Pure and stable top-emitting white organic light-emitting diodes utilizing heterojunction blue emission layers and wide-angle interference.

    PubMed

    Deng, Lingling; Shi, Hongying; Meng, Xue; Chen, Shufen; Zhou, Hongwei; Xu, Ying; Li, Xingao; Wang, Lianhui; Liu, Bin; Huang, Wei

    2014-04-09

    In top-emitting white organic light-emitting diodes (TWOLEDs), it is usually difficult to realize a good chromaticity due to the strong suppression on the blue emission induced by the microcavity effect. In our work, the blue emission layer (EML) is located near the hole transport layer and the reflective anode to strengthen the wide-angle interference on the blue emission and enhance the output of light. Then we utilize the dual blue EMLs based on an electron-rich heterojunction to constrain most of the excitons in the blue EMLs. With the above two strategies, the intensity of the blue emission is significantly enhanced accompanying the chromaticity improvement in white emission. Some key factors including exciton distribution, energy transfer, and carrier trapping are analyzed to design the structure of the EMLs to acquire the pure and stable white emission. The excellent color stability with a Commission International de L'Eclairage (CIE) coordinate drift of only (0.009, 0.001) in the luminance range of 10-10(4) cd/m(2) is obtained in our optimized TWOLED. The TWOLED also shows the high performances with a maximum luminance of 15360 cd/m(2), the CIE coordinates of (0.33, 0.41), and a current efficiency of 13.3 cd/A.

  17. Piezoelectric Resonator with Two Layers

    NASA Technical Reports Server (NTRS)

    Stephanou, Philip J. (Inventor); Black, Justin P. (Inventor)

    2013-01-01

    A piezoelectric resonator device includes: a top electrode layer with a patterned structure, a top piezoelectric layer adjacent to the top layer, a middle metal layer adjacent to the top piezoelectric layer opposite the top layer, a bottom piezoelectric layer adjacent to the middle layer opposite the top piezoelectric layer, and a bottom electrode layer with a patterned structure and adjacent to the bottom piezoelectric layer opposite the middle layer. The top layer includes a first plurality of electrodes inter-digitated with a second plurality of electrodes. A first one of the electrodes in the top layer and a first one of the electrodes in the bottom layer are coupled to a first contact, and a second one of the electrodes in the top layer and a second one of the electrodes in the bottom layer are coupled to a second contact.

  18. Spatial and Temporal Variation of Boundary Layer Lapse Rate and Cloud-top-height Observed from MODIS, CALIPSO and AMSR-E over Eastern Pacific

    NASA Astrophysics Data System (ADS)

    Adhikari, L.; Xie, F.; Winning, T.

    2015-12-01

    The strong free tropospheric subsidence and the cool sea surface temperatures over the subtropical eastern Pacific Ocean often lead to a shallow and cloudy planetary boundary layer (PBL) capped by a strong inversion. These low PBL clouds are crucial for understanding the ocean-atmosphere interaction and the cloud-radiation feedback processes. However, accurate identification/representation of these clouds remains a key challenge in both satellite observations and global climate model simulations. Specifically, the cloud transition from the near-shore stratocumulus to trade-cumulus remains a huge challenge in climate models and warrants high-quality PBL observations from space. The MODIS collection 6 cloud top height vastly improves the global PBL cloud top heights (CTH) compared to collection 5. However, the MODIS collection 6 CTH still shows systematic higher CTH than CALIPSO in the subtropical subsidence region, which is likely due to the underestimation of lapse rate. This study presents the seasonal climatology of PBL lapse rate derived from multi-year CALIPSO with co-incident MODIS CTT and AMSR-E SST measurements. The lapse rate climatology is validated by the high-resolution radiosonde observations and then used to derive the CTH from MODIS measurements. Comparison of the new lapse rate based MODIS CTH with CALIPSO CTH will be presented. The PBL height derived from the COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) GPS radio occultation (RO) will be used to evaluate the MODIS CTH as an independent dataset. The discrepancies over the transition from stratus to trade-cumuli regions (broken clouds) will also be discussed.

  19. Tunneling-Magnetoresistance Ratio Comparison of MgO-Based Perpendicular-Magnetic-Tunneling-Junction Spin Valve Between Top and Bottom Co2Fe6B2 Free Layer Structure

    NASA Astrophysics Data System (ADS)

    Lee, Du-Yeong; Lee, Seung-Eun; Shim, Tae-Hun; Park, Jea-Gun

    2016-09-01

    For the perpendicular-magnetic-tunneling-junction (p-MTJ) spin valve with a nanoscale-thick bottom Co2Fe6B2 free layer ex situ annealed at 400 °C, which has been used as a common p-MTJ structure, the Pt atoms of the Pt buffer layer diffused into the MgO tunneling barrier. This transformed the MgO tunneling barrier from a body-centered cubic (b.c.c) crystallized layer into a mixture of b.c.c, face-centered cubic, and amorphous layers and rapidly decreased the tunneling-magnetoresistance (TMR) ratio. The p-MTJ spin valve with a nanoscale-thick top Co2Fe6B2 free layer could prevent the Pt atoms diffusing into the MgO tunneling barrier during ex situ annealing at 400 °C because of non-necessity of a Pt buffer layer, demonstrating the TMR ratio of ~143 %.

  20. A model for the estimation of the surface fluxes of momentum, heat and moisture of the cloud topped marine atmospheric boundary layer from satellite measurable parameters. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Allison, D. E.

    1984-01-01

    A model is developed for the estimation of the surface fluxes of momentum, heat, and moisture of the cloud topped marine atmospheric boundary layer by use of satellite remotely sensed parameters. The parameters chosen for the problem are the integrated liquid water content, q sub li, the integrated water vapor content, q sub vi, the cloud top temperature, and either a measure of the 10 meter neutral wind speed or the friction velocity at the surface. Under the assumption of a horizontally homogeneous, well-mixed boundary layer, the model calculates the equivalent potential temperature and total water profiles of the boundary layer along with the boundary layer height from inputs of q sub li, q sub vi, and cloud top temperature. These values, along with the 10m neutral wind speed or friction velocity and the sea surface temperature are then used to estimate the surface fluxes. The development of a scheme to parameterize the integrated water vapor outside of the boundary layer for the cases of cold air outbreak and California coastal stratus is presented.

  1. Reorientation of the ‘free OH’ group in the top-most layer of air/water interface of sodium fluoride aqueous solution probed with sum-frequency generation vibrational spectroscopy

    SciTech Connect

    Feng, Ran-Ran; Guo, Yuan; Wang, Hongfei

    2014-09-17

    Many experimental and theoretical studies have established the specific anion, as well as cation effects on the hydrogen-bond structures at the air/water interface of electrolyte solutions. However, the ion effects on the top-most layer of the air/water interface, which is signified by the non-hydrogen-bonded so-called ‘free O-H’ group, has not been discussed or studied. In this report, we present the measurement of changes of the orientational angle of the ‘free O-H’ group at the air/water interface of the sodium fluoride (NaF) solutions at different concentrations using the interface selective sum-frequency generation vibrational spectroscopy (SFG-VS) in the ssp and ppp polarizations. The polarization dependent SFG-VS results show that the average tilt angle of the ‘free O-H’ changes from about 35.3 degrees ± 0.5 degrees to 43.4 degrees ± 2.1degrees as the NaF concentration increase from 0 to 0.94M (nearly saturated). Such tilt angle change is around the axis of the other O-H group of the same water molecule at the top-most layer at the air/water interface that is hydrogen-bonded to the water molecules below the top-most layer. These results provide quantitative molecular details of the ion effects of the NaF salt on the structure of the water molecules at the top-most layer of the air/water interfacial, even though both the Na+ cation and the F- anion are believed to be among the most excluded ions from the air/water interface.

  2. Architectural Tops

    ERIC Educational Resources Information Center

    Mahoney, Ellen

    2010-01-01

    The development of the skyscraper is an American story that combines architectural history, economic power, and technological achievement. Each city in the United States can be identified by the profile of its buildings. The design of the tops of skyscrapers was the inspiration for the students in the author's high-school ceramic class to develop…

  3. Tunneling-Magnetoresistance Ratio Comparison of MgO-Based Perpendicular-Magnetic-Tunneling-Junction Spin Valve Between Top and Bottom Co2Fe6B2 Free Layer Structure.

    PubMed

    Lee, Du-Yeong; Lee, Seung-Eun; Shim, Tae-Hun; Park, Jea-Gun

    2016-12-01

    For the perpendicular-magnetic-tunneling-junction (p-MTJ) spin valve with a nanoscale-thick bottom Co2Fe6B2 free layer ex situ annealed at 400 °C, which has been used as a common p-MTJ structure, the Pt atoms of the Pt buffer layer diffused into the MgO tunneling barrier. This transformed the MgO tunneling barrier from a body-centered cubic (b.c.c) crystallized layer into a mixture of b.c.c, face-centered cubic, and amorphous layers and rapidly decreased the tunneling-magnetoresistance (TMR) ratio. The p-MTJ spin valve with a nanoscale-thick top Co2Fe6B2 free layer could prevent the Pt atoms diffusing into the MgO tunneling barrier during ex situ annealing at 400 °C because of non-necessity of a Pt buffer layer, demonstrating the TMR ratio of ~143 %.

  4. Topography preserved microwave plasma etching for top-down layer engineering in MoS2 and other van der Waals materials.

    PubMed

    Varghese, Abin; Sharma, Chithra H; Thalakulam, Madhu

    2017-03-17

    A generic and universal layer engineering strategy for van der Waals (vW) materials, scalable and compatible with the current semiconductor technology, is of paramount importance in realizing all-two-dimensional logic circuits and to move beyond the silicon scaling limit. In this letter, we demonstrate a scalable and highly controllable microwave plasma based layer engineering strategy for MoS2 and other vW materials. Using this technique we etch MoS2 flakes layer-by-layer starting from an arbitrary thickness and area down to the mono- or the few-layer limit. From Raman spectroscopy, atomic force microscopy, photoluminescence spectroscopy, scanning electron microscopy and transmission electron microscopy, we confirm that the structural and morphological properties of the material have not been compromised. The process preserves the pre-etch layer topography and yields a smooth and pristine-like surface. We explore the electrical properties utilising a field effect transistor geometry and find that the mobility values of our samples are comparable to those of the pristine ones. The layer removal does not involve any reactive gasses or chemical reactions and relies on breaking the weak inter-layer vW interaction making it a generic technique for a wide spectrum of layered materials and heterostructures. We demonstrate the wide applicability of the technique by extending it to other systems such as graphene, h-BN and WSe2. In addition, using microwave plasma in combination with standard lithography, we illustrate a lateral patterning scheme making this process a potential candidate for large scale device fabrication in addition to layer engineering.

  5. The properties of thickness-twist (TT) wave modes in a rotated Y-cut quartz plate with a functionally graded material top layer.

    PubMed

    Wang, Bin; Qian, Zhenghua; Li, Nian; Sarraf, Hamid

    2016-01-01

    We propose the use of thickness-twist (TT) wave modes of an AT-cut quartz crystal plate resonator for measurement of material parameters, such as stiffness, density and material gradient, of a functionally graded material (FGM) layer on its surface, whose material property varies exponentially in thickness direction. A theoretical analysis of dispersion relations for TT waves is presented using Mindlin's plate theory, with displacement mode shapes plotted, and the existence of face-shear (FS) wave modes discussed. Through numerical examples, the effects of material parameters (stiffness, density and material gradient) on dispersion curves, cutoff frequencies and mode shapes are thoroughly examined, which can act as a theoretical reference for measurements of unknown properties of FGM layer.

  6. The study of origin of interfacial perpendicular magnetic anisotropy in ultra-thin CoFeB layer on the top of MgO based magnetic tunnel junction

    NASA Astrophysics Data System (ADS)

    Li, Zhi-Peng; Li, Shaoping; Zheng, Yuankai; Fang, Jason; Chen, Lifan; Hong, Liang; Wang, Haifeng

    2016-10-01

    A comprehensive microstructure study has been conducted experimentally for identifying the origin or mechanism of perpendicular magnetic anisotropy (PMA) in the ultra-thin (10 Å) CoFeB layer on the top of magnetic tunnel junction (MTJ). The high resolution transmission electron microscopy reveals that the feature of crystal structure in 10 Å-CoFeB layer is localized in nature at the CoFeB-MgO interface. On the other hand, the strain-relaxed crystalline structure is observed in the thick CoFeB (20 Å) layer at the CoFeB-MgO interface, associated with a series of dislocation formations. The electron energy loss spectroscopy further suggests that the local chemical stoichiometry of the ultra-thin 10 Å-CoFeB layer is notably changed at the CoFeB-MgO interface, compared with an atomic stoichiometry in a thick 20 Å-CoFeB layer. The origin of PMA mechanism is therefore identified experimentally as an interface effect, which can be attributed to a change of local atom bonding or lattice constant of the transition metal at the CoFeB-MgO based MTJ interface. Furthermore, such a local interfacial atom bonding change is seemly induced by the localized anisotropic strain and consistent with previous theoretical speculations and calculations. The observed experimental findings provide some perspective on microstructure and chemistry on PMA in ultra-thin CoFeB film at the MTJ interface, then deepening our understanding of the mechanism of PMA within MTJ stack and thus facilitating advancement for emerging spintronics technology.

  7. Characteristics of trace gases and aerosols at top of urban canopy layer in Nanjing of China from one year observational study

    NASA Astrophysics Data System (ADS)

    Wang, Tijian

    2013-04-01

    To understand the physical and chemical processes of air pollution formation in urban and their linkage with climate change in Yangtze River Delta(YRD), the fast developing area in China, a monitoring site was built on the top of a high building in the center of Nanjing. The site was set up to investigate the long term variations of trace gases and aerosols, which may play important roles in air pollution and climate change in regional scale. From one year measurement records, the annual average concentrations of ozone, sulfur dioxide, carbon monoxide, carbon dioxide, nitric oxide, total reactive nitrogen, water vapor are reported as 161.9±19.4 ppb, 93.8±8.9 ppb, 3856.7±412.1 ppb, 565.1±20.0 ppm, 173.6±15.6 ppb, 230.8±24.9 ppb, 34.76±7.2x10-3, respectively. PM10, PM2.5, visibility, black carbon, back scattering of particles(BSP), single scattering albedo(SSA), aerosol optical depth(AOD) and Angstrom wavelength exponent (AWE) are 115±113.1 μg/m3, 54±46.1 μg/m3, 9780±5594 m, 3055.9±2102.3 ng/m3, 66.3±97.5 Mm-1, 0.5±2.4, 0.7±0.38 and 1.22±0.28, respectively. Measurement show that the levels of air pollutants in YRD in East China are high compared to Pearl River Delta(PRD) in South China and Jing-Jin-Ji (JJJ) in North China, suggesting a possible stronger effect on atmospheric environment, climate change and human health in this region, which should be further addressed in the future study.

  8. Metal-silicate Partitioning of Uranium and Thorium up to 138 GPa and 5500 K and Implications for Stratified Layer at the Top of the Outer Core

    NASA Astrophysics Data System (ADS)

    Nomura, R.; Hirose, K.; Kimura, J. I.; Chang, Q.

    2014-12-01

    The excess abundances of siderophile elements in the mantle can be explained by metal-silicate equilibrium at mid-mantle depths in magma ocean of the growing Earth. The final equilibrium pressure and temperature would reach 37-60 GPa and melting temperature of the mantle at this pressure (Wade et al. 2012; Siebert et al., 2013). Much severe conditions (>6000 K) have been supposed at the final stage of the Earth's formation immediate aftermath the moon-forming giant impact (e.g. Canup, 2004), evoking the additional chemical equilibrium between core materials of the giant impactor and the surrounding silicate materials. Previous studies on partitioning of U up to 20 GPa and 2700 K by multi-anvil press have shown very small partition coefficients (D ~10^-5) in S-poor system with oxygen fugacity at around IW-1.5 (Wheeler et al., 2006; Bouhifd et al., 2013). Such a very small D make it difficult to examine the partitioning at higher P-T using laser-heated diamond anvil cell (LH-DAC) and electron microprobe since the small size of each phase introduce artificial error by such as secondary fluorescent effect (Wade and Wood, 2012). 1% contamination from surrounding silicate may increase D by three orders (i.e. D =10^-2), artificially. One solution is to use laser ablation ICP-MS by carefully ablating only a metallic portion. Here, we introduced FIB to isolate the metallic phase from the surrounding silicate melt by slicing off surrounding silicate potion. Consequently, we have successfully obtained the metal-silicate partitioning data of U and Th up to 138 GPa and 5500 K in S-free/S-poor system using LH-DAC. The results show a large temperature dependence of partition coefficient of uranium and thorium, approaching to 0.1~1 at temperature near 5500 K. The pressure dependence was not observed clearly. The large temperature dependence suggests that only the core material of the giant impactor can be enriched in U and Th, which may stratify at the top of the liquid core.

  9. Comparative analysis of (239)Pu, (137)Cs, (210)Pb and (40)K spatial distributions in the top soil layer at the Baltic coast.

    PubMed

    Luksiene, B; Druteikiene, R; Gvozdaite, R; Gudelis, A

    2006-01-01

    This paper presents the results of an investigation into the spatial distribution of radionuclides of artificial ((239,240)Pu, (137)Cs) and natural ((210)Pb, (40)K) origins in the upper (0-5 cm) soil layers on the Baltic coastline of Lithuania ( approximately 5 km(2) area). The samples were analysed by gamma ray spectrometry and combined radiochemical procedures. The highest (210)Pb, (239,240)Pu and (137)Cs activity concentrations were determined in the forest samples, whereas (40)K activity was rather homogeneous across the study area. Relatively high (239,240)Pu and (40)K activity concentrations were determined along the surf zone. The (210)Pb and (137)Cs activity concentrations showed a gradual increase from the surf zone to the forest. The average activity concentrations of (239,240)Pu, (137)Cs, (210)Pb and (40)K in the beach and forest samples, respectively, were as follows: 0.32+/-0.08 and 0.74+/-0.14; 50+/-4 and 1190+/-50; 4.7+/-2.0 and 48+/-6; 186+/-15 and 216+/-17 Bq/kg.

  10. Endurance and Cycle-to-cycle Uniformity Improvement in Tri-Layered CeO2/Ti/CeO2 Resistive Switching Devices by Changing Top Electrode Material

    PubMed Central

    Rana, Anwar Manzoor; Akbar, Tahira; Ismail, Muhammad; Ahmad, Ejaz; Hussain, Fayyaz; Talib, Ijaz; Imran, Muhammad; Mehmood, Khalid; Iqbal, Khalid; Nadeem, M. Younus

    2017-01-01

    Resistance switching characteristics of CeO2/Ti/CeO2 tri-layered films sandwiched between Pt bottom electrode and two different top electrodes (Ti and TaN) with different work functions have been investigated. RRAM memory cells composed of TaN/CeO2/Ti/CeO2/Pt reveal better resistive switching performance instead of Ti/CeO2/Ti/CeO2/Pt memory stacks. As compared to the Ti/CeO2 interface, much better ability of TaN/CeO2 interface to store and exchange plays a key role in the RS performance improvement, including lower forming/SET voltages, large memory window (~102) and no significant data degradation during endurance test of >104 switching cycles. The formation of TaON thinner interfacial layer between TaN TE and CeO2 film is found to be accountable for improved resistance switching behavior. Partial charge density of states is analyzed using density functional theory. It is found that the conductive filaments formed in CeO2 based devices is assisted by interstitial Ti dopant. Better stability and reproducibility in cycle-to-cycle (C2C) resistance distribution and Vset/Vreset uniformity were achieved due to the modulation of current conduction mechanism from Ohmic in low field region to Schottky emission in high field region. PMID:28079056

  11. Endurance and Cycle-to-cycle Uniformity Improvement in Tri-Layered CeO2/Ti/CeO2 Resistive Switching Devices by Changing Top Electrode Material.

    PubMed

    Rana, Anwar Manzoor; Akbar, Tahira; Ismail, Muhammad; Ahmad, Ejaz; Hussain, Fayyaz; Talib, Ijaz; Imran, Muhammad; Mehmood, Khalid; Iqbal, Khalid; Nadeem, M Younus

    2017-01-12

    Resistance switching characteristics of CeO2/Ti/CeO2 tri-layered films sandwiched between Pt bottom electrode and two different top electrodes (Ti and TaN) with different work functions have been investigated. RRAM memory cells composed of TaN/CeO2/Ti/CeO2/Pt reveal better resistive switching performance instead of Ti/CeO2/Ti/CeO2/Pt memory stacks. As compared to the Ti/CeO2 interface, much better ability of TaN/CeO2 interface to store and exchange plays a key role in the RS performance improvement, including lower forming/SET voltages, large memory window (~10(2)) and no significant data degradation during endurance test of >10(4) switching cycles. The formation of TaON thinner interfacial layer between TaN TE and CeO2 film is found to be accountable for improved resistance switching behavior. Partial charge density of states is analyzed using density functional theory. It is found that the conductive filaments formed in CeO2 based devices is assisted by interstitial Ti dopant. Better stability and reproducibility in cycle-to-cycle (C2C) resistance distribution and Vset/Vreset uniformity were achieved due to the modulation of current conduction mechanism from Ohmic in low field region to Schottky emission in high field region.

  12. Endurance and Cycle-to-cycle Uniformity Improvement in Tri-Layered CeO2/Ti/CeO2 Resistive Switching Devices by Changing Top Electrode Material

    NASA Astrophysics Data System (ADS)

    Rana, Anwar Manzoor; Akbar, Tahira; Ismail, Muhammad; Ahmad, Ejaz; Hussain, Fayyaz; Talib, Ijaz; Imran, Muhammad; Mehmood, Khalid; Iqbal, Khalid; Nadeem, M. Younus

    2017-01-01

    Resistance switching characteristics of CeO2/Ti/CeO2 tri-layered films sandwiched between Pt bottom electrode and two different top electrodes (Ti and TaN) with different work functions have been investigated. RRAM memory cells composed of TaN/CeO2/Ti/CeO2/Pt reveal better resistive switching performance instead of Ti/CeO2/Ti/CeO2/Pt memory stacks. As compared to the Ti/CeO2 interface, much better ability of TaN/CeO2 interface to store and exchange plays a key role in the RS performance improvement, including lower forming/SET voltages, large memory window (~102) and no significant data degradation during endurance test of >104 switching cycles. The formation of TaON thinner interfacial layer between TaN TE and CeO2 film is found to be accountable for improved resistance switching behavior. Partial charge density of states is analyzed using density functional theory. It is found that the conductive filaments formed in CeO2 based devices is assisted by interstitial Ti dopant. Better stability and reproducibility in cycle-to-cycle (C2C) resistance distribution and Vset/Vreset uniformity were achieved due to the modulation of current conduction mechanism from Ohmic in low field region to Schottky emission in high field region.

  13. In-Situ Fabrication of a Self-Aligned Selective Emitter Silicon Solar Cell Using the Gold Top Contacts To Facilitate the Synthesis of a Nanostructured Black Silicon Antireflective Layer Instead of an External Metal Nanoparticle Catalyst.

    PubMed

    Lu, Yen-Tien; Barron, Andrew R

    2015-06-10

    Silicon solar cells with nanopore-type black silicon (b-Si) antireflection (AR) layers and self-aligned selective emitter (SE) are reported in which the b-Si structure is prepared without the traditional addition of a nanoparticle (NP) catalyst. The contact-assisted chemical etching (CACE) method is reported here for the first time, in which the metal top contacts on silicon solar cell surfaces function as the catalysts for b-Si fabrication and the whole etching process can be done in minutes at room temperature. The CACE method is based on the metal-assisted chemical etching (MACE) solution but without or metal precursor in the Si etchant (HF:H2O2:H2O), and the Au top contacts, or catalysts, are not removed from the solar cell surface after the etching. The effects of etching time, HF and H2O2 concentration, and the HF:H2O2 ratio on the b-Si morphology, surface reflectivity, and solar cell efficiency have been investigated. Higher [HF] and [H2O2] with longer etching time cause collapse of the b-Si nanoporous structure and penetration of the p-n junctions, which are detrimental to the solar cell efficiency. The b-Si solar cell fabricated with the HF:H2O2:H2O volume ratio of 3:3:20 and a 3 min etch time shows the highest efficiency 8.99% along with a decrease of reflectivity from 36.1% to 12.6% compared to that of the nonetched Si solar cell.

  14. Strategies to increase laser damage performance of Ta2O5/SiO2 mirrors by modifications of the top layer design.

    PubMed

    Schiltz, Drew; Patel, Dinesh; Baumgarten, Cory; Reagan, Brendan A; Rocca, Jorge J; Menoni, Carmen S

    2017-02-01

    Ta2O5/SiO2 high reflection (HR) interference coatings for λ∼1  μm offer superior performance at high irradiance conditions. However, these coatings are not good candidates for high peak power conditions in comparison to HfO2/SiO2 multilayer stacks. Here we show that the modification of the top layers design of a quarter wave Ta2O5/SiO2 high reflector leads to 4-5 fold increase in the laser damage fluence compared to a quarter wave (Ta2O5/SiO2)15 when tested at λ=1.03  μm using pulse durations of 0.19 and 4 ns and peak power densities of 43.5 and 216  GW/cm2. One of the designs achieved a laser damage threshold fluence of 174  J/cm2 at 4 ns, which is 10% higher than that of a HfO2/SiO2 quarter wave design.

  15. Top physics at CDF

    SciTech Connect

    Julia Thom

    2004-06-24

    Precision studies of top quark properties are a primary goal of the Run II physics program at the Fermilab Tevatron. Marking the first stages of this program, the CDF collaboration presents recent results on top pair production cross section, single top physics and top mass, using between 109 and 200 pb{sup -1} of Run II data.

  16. Top quark physics

    SciTech Connect

    Ahmadov, A.; Azuelos, G.; Bauer, U.; Belyaev, A.; Berger, E. L.; Sullivan, Z.; Tait, T. M. P.

    2000-03-24

    The top quark, when it was finally discovered at Fermilab in 1995 completed the three-generation structure of the Standard Model (SM) and opened up the new field of top quark physics. Viewed as just another SM quark, the top quark appears to be a rather uninteresting species. Produced predominantly, in hadron-hadron collisions, through strong interactions, it decays rapidly without forming hadrons, and almost exclusively through the single mode t {r_arrow} Wb. The relevant CKM coupling V{sub tb} is already determined by the (three-generation) unitarity of the CKM matrix. Rare decays and CP violation are unmeasurable small in the SM. Yet the top quark is distinguished by its large mass, about 35 times larger than the mass of the next heavy quark, and intriguingly close to the scale of electroweak (EW) symmetry breaking. This unique property raises a number of interesting questions. Is the top quark mass generated by the Higgs mechanism as the SM predicts and is its mass related to the top-Higgs-Yukawa coupling? Or does it play an even more fundamental role in the EW symmetry breaking mechanism? If there are new particles lighter than the top quark, does the top quark decay into them? Could non-SM physics first manifest itself in non-standard couplings of the top quark which show up as anomalies in top quark production and decays? Top quark physics tries to answer these questions. Several properties of the top quark have already been examined at the Tevatron. These include studies of the kinematical properties of top production, the measurements of the top mass, of the top production cross-section, the reconstruction of t{bar t}pairs in the fully hadronic final states, the study of {tau} decays of the top quark, the reconstruction of hadronic decays of the W boson from top decays, the search for flavor changing neutral current decays, the measurement of the W helicity in top decays, and bounds on t{bar t} spin correlations. Most of these measurements are limited by

  17. Spherical Tippe Tops

    ERIC Educational Resources Information Center

    Cross, Rod

    2013-01-01

    A tippe top (see Fig. 1) is usually constructed as a truncated sphere with a cylindrical peg on top, as indicated in Fig. 2(a). When spun rapidly on a horizontal surface, a tippe top spins about a vertical axis while rotating slowly about a horizontal axis until the peg touches the surface. At that point, weight is transferred to the peg, the…

  18. Dare We Teach Tops?

    ERIC Educational Resources Information Center

    Featonby, David

    2010-01-01

    "Tops" are mentioned in classical literature and references are even found in the ancient world. For many children a top is one of the first mechanical toys that they play with by themselves, yet a full appreciation of their motion is rare. My hope is that this article will stimulate the reader's interest in tops, will help with the first stages…

  19. CDF Top Physics

    DOE R&D Accomplishments Database

    Tartarelli, G. F.; CDF Collaboration

    1996-05-01

    The authors present the latest results about top physics obtained by the CDF experiment at the Fermilab Tevatron collider. The data sample used for these analysis (about 110 pb{sup{minus}1}) represents almost the entire statistics collected by CDF during four years (1992--95) of data taking. This large data size has allowed detailed studies of top production and decay properties. The results discussed here include the determination of the top quark mass, the measurement of the production cross section, the study of the kinematics of the top events and a look at top decays.

  20. CDF top physics

    SciTech Connect

    Tartarelli, G.F.; CDF Collaboration

    1996-05-01

    The authors present the latest results about top physics obtained by the CDF experiment at the Fermilab Tevatron collider. The data sample used for these analysis (about 110 pb{sup {minus}1}) represents almost the entire statistics collected by CDF during four years (1992--95) of data taking. This large data size has allowed detailed studies of top production and decay properties. The results discussed here include the determination of the top quark mass, the measurement of the production cross section, the study of the kinematics of the top events and a look at top decays.

  1. Multi-layer coatings

    DOEpatents

    Maghsoodi, Sina; Brophy, Brenor L.; Abrams, Ze'ev R.; Gonsalves, Peter R.

    2016-06-28

    Disclosed herein are coating materials and methods for applying a top-layer coating that is durable, abrasion resistant, highly transparent, hydrophobic, low-friction, moisture-sealing, anti-soiling, and self-cleaning to an existing conventional high temperature anti-reflective coating. The top coat imparts superior durability performance and new properties to the under-laying conventional high temperature anti-reflective coating without reducing the anti-reflectiveness of the coating. Methods and data for optimizing the relative thickness of the under-layer high temperature anti-reflective coating and the top-layer thickness for optimizing optical performance are also disclosed.

  2. TopN-Pareto Front Search

    SciTech Connect

    Anderson-Cook, Christine M.; Lu, Lu; Burke, Sarah E.

    2016-12-21

    The JMP Add-In TopN-PFS provides an automated tool for finding layered Pareto front to identify the top N solutions from an enumerated list of candidates subject to optimizing multiple criteria. The approach constructs the N layers of Pareto fronts, and then provides a suite of graphical tools to explore the alternatives based on different prioritizations of the criteria. The tool is designed to provide a set of alternatives from which the decision-maker can select the best option for their study goals.

  3. The Top Triangle Moose

    NASA Astrophysics Data System (ADS)

    Chivukula, R. S.; Christensen, N. D.; Coleppa, B.; Simmons, E. H.

    2011-01-01

    We introduce a deconstructed model that incorporates both Higgsless and top-color mechanisms. The model alleviates the typical tension in Higgsless models between obtaining the correct top quark mass and keeping Δρ small. It does so by singling out the top quark mass generation as arising from a Yukawa coupling to an effective top-Higgs which develops a small vacuum expectation value, while electroweak symmetry breaking results largely from a Higgsless mechanism. As a result, the heavy partners of the SM fermions can be light enough to be seen at the LHC.

  4. Top Physics at CDF

    SciTech Connect

    Moon, Chang-Seong

    2011-06-01

    We present the recent results of top-quark physics using up to 6 fb{sup -1} of p{bar p} collisions at a center of mass energy of {radical}s = 1.96 TeV analyzed by the CDF collaboration. Thanks to this large data sample, precision top quark measurements are now a reality at the Tevatron. Further, several new physics signals could appear in this large dataset. We will present the latest measurements of top quark intrinsic properties as well as direct searches for new physics in the top sector.

  5. Training Top 125

    ERIC Educational Resources Information Center

    Training, 2011

    2011-01-01

    Top companies realize how vital training is to their success and continue to invest in it, even in trying times. This article presents "Training" magazine's 11th annual ranking of the top companies with employee-sponsored workforce training and development. First-time No. 1 winner Farmers Insurance puts such a premium on learning that its new…

  6. The Driven Spinning Top

    ERIC Educational Resources Information Center

    Grosu, Ioan; Featonby, David

    2016-01-01

    This driven top is quite a novelty and can, with some trials, be made using the principles outlined here. This new top has many applications in developing both understanding and skills and these are detailed in the article. Depending on reader's available time and motivation they may feel an urge to make one themselves, or simply invest a few…

  7. Training Top 125

    ERIC Educational Resources Information Center

    Training, 2012

    2012-01-01

    The best learning and development organizations support business initiatives tactically "and" help drive strategic change. Verizon did just that, earning it the No. 1 spot for the first time on the Training Top 125. Verizon and the other 2012 Top 125 winners continued to invest in training, collectively dedicating a mean of 4.52 percent of their…

  8. Top search at CDF

    SciTech Connect

    Contreras, M.; The CDF Collaboration

    1991-10-01

    We review top quark searches carried out at CDF with data collected during the 1988--1989 Collider Run. The latest analyses give a lower limit on the top quark mass of 91 GeV/c{sup 2} at the 95% confidence level, assuming Standard Model decays. 8 refs., 6 figs., 1 tab.

  9. Top physics at CDF

    SciTech Connect

    Hughes, R.E.

    1997-01-01

    We report on top physics results using a 100 pb{sup -1} data sample of p{bar p} collisions at {radical}s = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). We have identified top signals in a variety of decay channels, and used these channels to extract a measurement of the top mass and production cross section. A subset of the data (67 pb{sup -1}) is used to determine M{sub top} = 176 {+-} 8(stat) {+-} 10(syst) and {sigma}(tt) = 7.6 {sub -2.0}{sup +2.4} pb. We present studies of the kinematics of t{bar t} events and extract the first direct measurement of V{sub tb}. Finally, we indicate prospects for future study of top physics at the Tevatron.

  10. Top quark mass measurement

    SciTech Connect

    Maki, Tuula

    2008-03-18

    The top quark is the heaviest elementary particle. Its mass is one of the fundamental parameters of the standard model of particle physics, and an important input to precision electroweak tests. This thesis describes three measurements of the top-quark mass in the dilepton decay channel. The dilepton events have two neutrinos in the final state; neutrinos are weakly interacting particles that cannot be detected with a multipurpose experiment. Therefore, the signal of dilepton events consists of a large amount of missing energy and momentum carried off by the neutrinos. The top-quark mass is reconstructed for each event by assuming an additional constraint from a top mass independent distribution. Template distributions are constructed from simulated samples of signal and background events, and parametrized to form continuous probability density functions. The final top-quark mass is derived using a likelihood fit to compare the reconstructed top mass distribution from data to the parametrized templates. One of the analyses uses a novel technique to add top mass information from the observed number of events by including a cross-section-constraint in the likelihood function. All measurements use data samples collected by the CDF II detector.

  11. Top physics at CDF

    SciTech Connect

    Palencia, Enrique; /Cantabria Inst. of Phys.

    2006-06-01

    The top quark is the most massive fundamental particle observed so far, and the study of its properties is interesting for several reasons ranging from its possible special role in electroweak symmetry breaking to its sensitivity to physics beyond the Standard Model (SM). This article focuses on the latest top physics results from CDF based on 320-750 pb{sup -1} of p{bar p} collision data at {radical}s = 1.96 TeV. The t{bar t} cross section and the top mass have been measured in different decay channels and using different methods. They have also searched for massive t{bar t} resonances.

  12. Top quark mass measurements

    SciTech Connect

    Hill, Christopher S.; /UC, Santa Barbara

    2004-12-01

    The top quark, with its extraordinarily large mass (nearly that of a gold atom), plays a significant role in the phenomenology of EWSB in the Standard Model. In particular, the top quark mass when combined with the W mass constrains the mass of the as yet unobserved Higgs boson. Thus, a precise determination of the mass of the top quark is a principal goal of the CDF and D0 experiments. With the data collected thus far in Runs 1 and 2 of the Tevatron, CDF and D0 have measured the top quark mass in both the lepton+jets and dilepton decay channels using a variety of complementary experimental techniques. The author presents an overview of the most recent of the measurements.

  13. Top physics: CDF results

    SciTech Connect

    K. Bloom

    2004-06-23

    The top quark plays an important role in the grand scheme of particle physics, and is also interesting on its own merits. We present recent results from CDF on top-quark physics based on 100-200 pb{sup -1} of p{bar p} collision data. We have measured the t{bar t} cross section in different decay modes using several different techniques, and are beginning our studies of top-quark properties. New analyses for this conference include a measurement of {sigma}{sub t{bar t}} in the lepton-plus-jets channel using a neural net to distinguish signal and background events, and measurements of top-quark branching fractions.

  14. Top quark properties

    SciTech Connect

    Hong, Ziqing

    2014-10-31

    The top quark physics has entered the precision era. The CDF and D0 collaborations are finalizing their legacy results of the properties of the top quark after the shutdown of the Fermilab Tevatron three years ago. The ATLAS and CMS collaborations have been publishing results from the LHC Run I with 7 TeV and 8 TeV proton-proton collisions, with many more forthcoming. We present a selection of recent results produced by the Tevatron and LHC experiments.

  15. Kernel mucking in top

    SciTech Connect

    LeFebvre, W.

    1994-08-01

    For many years, the popular program top has aided system administrations in examination of process resource usage on their machines. Yet few are familiar with the techniques involved in obtaining this information. Most of what is displayed by top is available only in the dark recesses of kernel memory. Extracting this information requires familiarity not only with how bytes are read from the kernel, but also what data needs to be read. The wide variety of systems and variants of the Unix operating system in today`s marketplace makes writing such a program very challenging. This paper explores the tremendous diversity in kernel information across the many platforms and the solutions employed by top to achieve and maintain ease of portability in the presence of such divergent systems.

  16. Top-ophilia

    SciTech Connect

    Quigg, Chris; /Fermilab

    2008-01-01

    Almost from the moment in June 1977 when the discovery of the Upsilon resonance revealed the existence of what we now call the bottom quark, physicists began searching for its partner. Through the years, as we established the electric charge and weak isospin of the b-quark, and detected the virtual influence of its mate, it became clear that the top quark must exist. Exactly at what mass, we couldn't say, but we knew just how top events would look. We also knew that top events would be rare--if the Tevatron could make them at all--and that picking out the events would pose a real challenge for the experimenters and their detectors.

  17. TOPS optical correlation program

    NASA Astrophysics Data System (ADS)

    Lindell, Scott D.

    1993-09-01

    Martin Marietta is conducting a TOPS optical correlation program in which several algorithms and four optical correlators involving two spatial light modulator technologies will be developed and tested. The program will culminate in 1994 with an automatic target recognition flight demonstration using a UH-1 helicopter flying a Fiber Optic Guide Missile (FOG-M) mission profile. The flight demonstration will be conducted by US Army Missile Command (MICOM) and Martin Marietta and will involve detecting, locating and tracking a M60A2 tank positioned among an array of five vehicle types. Current status of the TOPS program will be given.

  18. TOPping off meiosis.

    PubMed

    Haber, James E

    2015-02-19

    Double-strand breaks (DSBs) threaten chromosome integrity. The most accurate repair of DSBs is by homologous recombination (HR), catalyzed by recombination proteins such as Rad51. Three papers in this issue of Molecular Cell (Fasching et al., 2015; Kaur et al., 2015; Tang et al., 2015) now reveal the role of three of these proteins in budding yeast: Sgs1 (BLM homolog), Top3 (TOPIIIα homolog), and Rmi1. They demonstrate several steps where all three proteins act together, and find additional functions of the Top3-Rmi1 subcomplex that are critical for the completion of meiosis.

  19. Top quark physics: Future measurements

    SciTech Connect

    Frey, R.; Vejcik, S.; Berger, E.L.

    1997-04-04

    The authors discuss the study of the top quark at future experiments and machines. Top`s large mass makes it a unique probe of physics at the natural electroweak scale. They emphasize measurements of the top quark`s mass, width, and couplings, as well as searches for rare or nonstandard decays, and discuss the complementary roles played by hadron and lepton colliders.

  20. Experimental Study of Top Heat Mode Thermosyphon

    NASA Astrophysics Data System (ADS)

    Hirashima, Masao; Kimura, Kenichiro; Utsumi, Yoichi; Kimura, Kenichi; Negishi, Kanji

    The purpose of this study is to develop the top heat mode thermosyphon that is very attractive means, for example, to accumulate directly the summer solar energy into the underground soil for the winter season. In this case, it can exclude the complex piping and mechanical pump to circulate the hot water absorbed the solar energy through the piping system buried in the soil layer. The several ideas concerning the top heat thermosyphon had been proposed, however, there were few reports on the definite experiments. The authors have carried out the experimental study of the top heat mode thermosyphon, with a simple lifting pipe, which could draw the working liquid from the under condenser to the upper evaporator section. The improvement of the main construction parts such as evaporator, lifting pipe, liquid reservoir trap and vapour nozzle have been performed in the present experiment in order to obtain the optimum operation range.

  1. Ten Top Tech Trends

    ERIC Educational Resources Information Center

    McLester, Susan

    2008-01-01

    In this article, the author discusses the major technical issues, products, and practices of the day. The top ten tech trends are listed and discussed. These include: (1) data mining; (2) cyberbullying; (3) 21st century skills; (4) digital content; (5) learning at leisure; (6) personal responders; (7) mobile tools; (8) bandwidth; (9) open-source…

  2. Choosing a Top Ten.

    ERIC Educational Resources Information Center

    IUCN Bulletin, 1984

    1984-01-01

    Presents an annotated list of 34 animals and 32 plants which are candidates for a list of the top 10 endangered species. Also presents the criteria used to formulate these lists. They include the conservation value (urgency prominance, biological value) and operational considerations (such as cost factors) for each species. (JN)

  3. Four tops for LHC

    NASA Astrophysics Data System (ADS)

    Alvarez, Ezequiel; Faroughy, Darius A.; Kamenik, Jernej F.; Morales, Roberto; Szynkman, Alejandro

    2017-02-01

    We design a search strategy for the Standard Model t t bar t t bar production at the LHC in the same-sign dilepton and trilepton channels. We study different signal features and, given the small expected number of signal events, we scrutinize in detail all reducible and irreducible backgrounds. Our analysis shows that by imposing a basic set of jet and lepton selection criteria, the SM pp → t t bar t t bar process could be evidenced in the near future, within Run-II, when combining both multi-lepton search channels. We argue that this search strategy should also be used as a guideline to test New Physics coupling predominantly to top-quarks. In particular, we show that a non-resonant New Physics enhancement in the four-top final state would be detectable through this search strategy. We study two top-philic simplified models of this kind, a neutral scalar boson and a Z‧, and present current and future exclusion limits on their mass and couplings.

  4. 22. Top Lateral Bracing & Top Chord, Vertical Tension Member ...

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

    22. Top Lateral Bracing & Top Chord, Vertical Tension Member 6, end Vertical Compression Members 5 & 4; South Swing Span; looking N. - Pacific Shortline Bridge, U.S. Route 20,spanning Missouri River, Sioux City, Woodbury County, IA

  5. Cloud top entrainment instability and cloud top distributions

    NASA Technical Reports Server (NTRS)

    Boers, Reinout; Spinhirne, James D.

    1990-01-01

    Classical cloud-top entrainment instability condition formulation is discussed. A saturation point diagram is used to investigate the details of mixing in cases where the cloud-top entrainment instability criterion is satisfied.

  6. 7. DETAIL VIEW OF TOP CHORD AND TOP CHORD CONNECTION ...

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

    7. DETAIL VIEW OF TOP CHORD AND TOP CHORD CONNECTION - Springfield-Des Arc Bridge, Spanning North Branch of Cadron Creek at Old Springfield-Des Arc Road (County Road 222), Springfield, Conway County, AR

  7. Top quark physics at CDF

    SciTech Connect

    Nielsen, Jason

    2004-04-30

    The existence of the top quark, discovered by CDF and D0 in 1995, has been re-established in the burgeoning dataset being collected in Run 2 of the Tevatron at Fermilab. Results from CDF on the top quark production cross section and top quark mass are consistent with the Standard Model expectations. The well-characterized top data samples will make it possible in the future to probe further for new physics in the top quark sector. This report summarizes recent CDF top quark physics results.

  8. Top quark physics: Future Measurements

    SciTech Connect

    Frey, Raymond; Gerdes, David; Jaros, John; Vejcik, Steve; Berger, Edmond L.; Chivukula, R. Sekhar; Cuypers, Frank; Drell, Persis S.; Fero, Michael; Hadley, Nicholas; Han, Tao; Heinson, Ann P.; Knuteson, Bruce; Larios, Francisco; Miettinen, Hannu; Orr, Lynne H.; Peskin, Michael E.; Rizzo, Thomas; Sarid, Uri; Schmidt, Carl; Stelzer, Tim; Sullivan, Zack

    1996-12-31

    We discuss the study of the top quark at future experiments and machines. Top's large mass makes it a unique probe of physics at the natural electroweak scale. We emphasize measurements of the top quark's mass, width, and couplings, as well as searches for rare or nonstandard decays, and discuss the complementary roles played by hadron and lepton colliders.

  9. Top physics results at CDF

    SciTech Connect

    Vickey, Trevor; /Illinois U., Urbana

    2005-05-01

    The most recent results on top quark physics at CDF are reported. Measurements of cross-section and mass are presented, and the status of single top quark production searches are discussed. The results obtained from probing various top quark properties are also presented.

  10. Curly Top Disease of Tomato

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Curly top disease, caused by viruses in the genus, Curtovirus, has impacted western US agriculture for over a century; and is a significant threat to tomato production. The two most abundant curtovirus species today are Beet severe curly top virus (BSCTV) and Beet mild curly top virus (BMCTV) but ot...

  11. CDF results on top

    SciTech Connect

    Beretvas, A.; CDF Collaboration

    1995-08-01

    CDF has established the existence of the top quark. Results from p{anti p} collisions at {radical}s = 1.8 TeV are presented. In the dilepton final state the authors found seven events with a background of 1.3 {+-} 0.3. In the e, {mu} + {nu} + jets channel with a b identified via a secondary vertex detector (SVX), they found twenty one events with a background of 5.5 {+-} 1.8. They measure the top quark mass to be 176 {+-} 8 (stat) {+-} 10 (syst) GeV/c{sup 2}, and the t{anti t} production cross section to be 7.6{sub {minus}2.0}{sup +2.4} pb. The integrated luminosity for the results presented in this talk is 67 pb{sup {minus}1}. The CDF detector needs to be upgraded for the next run. The integrated luminosity for the next run is expected to be more than 1,000 pb{sup {minus}1}.

  12. Top quark mass measurements

    SciTech Connect

    L. Cerrito

    2004-07-16

    Preliminary results on the measurement of the top quark mass at the Tevatron Collider are presented. In the dilepton decay channel, the CDF Collaboration measures m{sub t} = 175.0{sub -16.9}{sup +17.4}(stat.){+-}8.4(syst.) GeV/c{sup 2}, using a sample of {approx} 126 pb{sup -1} of proton-antiproton collision data at {radical}s = 1.96 TeV (Run II). In the lepton plus jets channel, the CDF Collaboration measures 177.5{sub -9.4}{sup +12.7}(stat.) {+-} 7.1(syst.) GeV/c{sup 2}, using a sample of {approx} 102 pb{sup -1} at {radical}s = 1.96 TeV. The D0 Collaboration has newly applied a likelihood technique to improve the analysis of {approx} 125 pb{sup -1} of proton-antiproton collisions at {radical}s = 1.8 TeV (Run I), with the result: m{sub t} = 180.1 {+-} 3.6(stat.) {+-}3.9(syst.) GeV/c{sup 2}. The latter is combined with all the measurements based on the data collected in Run I to yield the most recent and comprehensive experimental determination of the top quark mass: m{sub t} = 178.0 {+-} 2.7(stat.) {+-} 3.3(syst.) GeV/c{sup 2}.

  13. Tall tower or mountain top measurements?

    NASA Astrophysics Data System (ADS)

    Bamberger, Ines; Eugster, Werner; Oney, Brian; Brunner, Dominik; Leuenberger, Markus; Schanda, Rüdiger; Henne, Stephan; Buchmann, Nina

    2014-05-01

    Resolving the regional transport and distribution of greenhouse gases in the troposphere is a key topic that challenges both modelers and experimentalists. A dense network of measurement stations would be required, in particular including measurements at high elevation to better represent the entire lower troposphere, and not only small-scale local conditions in the near-surface atmosphere. While this can be achieved by tall towers, also mountain top stations (e.g. Schauinsland, Brocken) and other stations at high elevation (e.g., Mouna Loa, Jungfraujoch) are often appropriate, due to their extended concentration footprint. However, especially over complex, mountainous terrain, the transport of atmospheric gases and their spatio-temporal distribution is difficult to predict due to the development of thermally induced local wind patterns and boundary layer processes. Therefore, the main goal of our study is to test to what extend boundary layer processes at the surface and local wind patterns close to the ground at a mountain top site influence the ambient greenhouse gas patterns compared to measurements taken at a similar altitude but at a tall tower site. To this end we use measurements from the Zugerberg mountain top station, located at a pre-Alpine mountain ridge (987 m a.s.l., 4 m above ground) exposed to the prevailing synoptic winds in Switzerland, and compare these measurements with a neighboring tall tower site (Beromünster radio broadcast tower with its top at 1014 m a.s.l., 217 m above local ground level, and ≡500 m above the Swiss Plateau). The Beromünster tall tower is located at a distance of only 30 km from the mountain top station as the bird flies, and hence a direct comparison minimizes confounding factors that are not related to the tall tower vs. mountain top position of the measurements. Both stations are part of the CarboCount CH greenhouse gas observation network (http://www.carbocount.ch) initiated for long-term monitoring and modeling of

  14. Top properties at the Tevatron

    SciTech Connect

    Chiarelli, G.; The CDF Collaboration

    1997-05-01

    We present the latest results associated with top properties at the Tevatron. The large data set collected in four years of running has allowed, after top discovery, the study of various top properties. The results presented here include the measurement of the CKM matrix element {vert_bar}V{sub if}{vert_bar}, the search for top FCNC, the study of properties of W in t decays and the search for heavy states decaying to tt pairs. Future measurements in top physics at the Tevatron are briefly discussed.

  15. Top quark pair production and top quark properties at CDF

    SciTech Connect

    Moon, Chang-Seong

    2016-06-02

    We present the most recent measurements of top quark pairs production and top quark properties in proton-antiproton collisions with center-of-mass energy of 1.96 TeV using CDF II detector at the Tevatron. The combination of top pair production cross section measurements and the direct measurement of top quark width are reported. The test of Standard Model predictions for top quark decaying into $b$-quarks, performed by measuring the ratio $R$ between the top quark branching fraction to $b$-quark and the branching fraction to any type of down quark is shown. The extraction of the CKM matrix element $|V_{tb}|$ from the ratio $R$ is discussed. We also present the latest measurements on the forward-backward asymmetry ($A_{FB}$) in top anti-top quark production. With the full CDF Run II data set, the measurements are performed in top anti-top decaying to final states that contain one or two charged leptons (electrons or muons). In addition, we combine the results of the leptonic forward-backward asymmetry in $t\\bar t$ system between the two final states. All the results show deviations from the next-to-leading order (NLO) standard model (SM) calculation.

  16. Top quark physics

    SciTech Connect

    Menzione, A.

    1995-10-01

    Most of the material presented in this report, comes from contributions to the parallel session PL20 of this conference. We summarise the experimental results of direct production of Top quarks, coming from the CDF and C0 Collaborations at Fermilab, and compare these results to what one expects within current theoretical understanding. Particular attention is given to new results such as all hadronic modes of t{bar t} decay. As far as the mass is concerned, a comparison is made with precision measurements of related quantities, coming from LEP and other experiments. An attempt is made to look at the medium-term future and understand which variables and with what accuracy one can measure them with increased integrated luminosity.

  17. Top-Higgs and top-pion phenomenology in the top triangle moose model

    NASA Astrophysics Data System (ADS)

    Chivukula, R. Sekhar; Simmons, Elizabeth H.; Coleppa, Baradhwaj; Logan, Heather E.; Martin, Adam

    2011-03-01

    We discuss the deconstructed version of a topcolor-assisted technicolor model wherein the mechanism of top quark mass generation is separated from the rest of electroweak symmetry breaking. The minimal deconstructed version of this scenario is a “triangle moose” model, where the top quark gets its mass from coupling to a top-Higgs field, while the gauge boson masses are generated from a Higgsless sector. The spectrum of the model includes scalar (top-Higgs) and pseudoscalar (top-pion) states. In this paper, we study the properties of these particles, discuss their production mechanisms and decay modes, and suggest how best to search for them at the LHC.

  18. Top-Higgs and top-pion phenomenology in the top triangle moose model

    SciTech Connect

    Chivukula, R. Sekhar; Simmons, Elizabeth H.; Coleppa, Baradhwaj; Logan, Heather E.; Martin, Adam

    2011-03-01

    We discuss the deconstructed version of a topcolor-assisted technicolor model wherein the mechanism of top quark mass generation is separated from the rest of electroweak symmetry breaking. The minimal deconstructed version of this scenario is a ''triangle moose'' model, where the top quark gets its mass from coupling to a top-Higgs field, while the gauge boson masses are generated from a Higgsless sector. The spectrum of the model includes scalar (top-Higgs) and pseudoscalar (top-pion) states. In this paper, we study the properties of these particles, discuss their production mechanisms and decay modes, and suggest how best to search for them at the LHC.

  19. Top physics results from CDF

    SciTech Connect

    Gomez, Gervasio; /Cantabria Inst. of Phys.

    2005-05-01

    The top quark is by far the most massive fundamental particle observed so far, and the study of its properties is interesting for several reasons ranging from its possible special role in electroweak symmetry breaking to its sensitivity to physics beyond the Standard Model. They present recent top physics results from CDF based on 160-320 pb{sup -1} of p{bar p} collision data at {radical}s = 1.96 TeV. The t{bar t} cross section and the top mass have been measured in different decay channels and using different methods. they have searched for evidence of single top production, setting upper limits on its production rate. Other results shown in this conference include studies of the polarization of W bosons from top decays, a search for charged Higgs decaying from top, and a search for additional heavy t' quarks.

  20. 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.

  1. Nanostructured Sublayers for Improved Light Extraction of Top-Emitting and Transparent Organic Electroluminescent Devices

    DTIC Science & Technology

    2007-05-01

    fabrication of top-emitting red, green, and blue OLEDs with various light emitting and hole transport layer thicknesses. (b) The layered structures of...the top-emitting red, green, and blue devices. (c) The materials used as hole transport layers, light emitting hosts, and dopants. Figure 4...transmittance of dielectric mirror with structure of TiO2 54nm /SiO2 90nm / TiO2 54nm /Glass Figure 12. Light emitting spectra of green microcavity

  2. Dark matter on top

    SciTech Connect

    Gómez, M.A.; Jackson, C.B.; Shaughnessy, G. E-mail: chris@uta.edu

    2014-12-01

    We consider a simplified model of fermionic dark matter which couples exclusively to the right-handed top quark via a renormalizable interaction with a color-charged scalar. We first compute the relic abundance of this type of dark matter and investigate constraints placed on the model parameter space by the latest direct detection data. We also perform a detailed analysis for the production of dark matter at the LHC for this model. We find several kinematic variables that allow for a clean signal extraction and we show that the parameter space of this model will be well probed during LHC Run-II. Finally, we investigate the possibility of detecting this type of dark matter via its annihilations into gamma rays. We compute the continuum and the line emission (which includes a possible ''Higgs in Space!'' line) and its possible discovery by future gamma-ray telescopes. We find that the annihilation spectrum has distinctive features which may distinguish it from other models.

  3. 4. DETAIL VIEW OF TOP CHORD AND TOP CHORD CONNECTIONS ...

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

    4. DETAIL VIEW OF TOP CHORD AND TOP CHORD CONNECTIONS NEAR NORTH CORNER OF BRIDGE, LOOKING WEST - Springfield-Des Arc Bridge, Spanning North Branch of Cadron Creek at Old Springfield-Des Arc Road (County Road 222), Springfield, Conway County, AR

  4. Top Sounder Ice Penetration

    NASA Astrophysics Data System (ADS)

    Porter, D. L.; Goemmer, S. A.; Sweeney, J. H.

    2014-12-01

    Ice draft measurements are made as part of normal operations for all US Navy submarines operating in the Arctic Ocean. The submarine ice draft data are unique in providing high resolution measurements over long transects of the ice covered ocean. The data has been used to document a multidecadal drop in ice thickness, and for validating and improving numerical sea-ice models. A submarine upward-looking sonar draft measurement is made by a sonar transducer mounted in the sail or deck of the submarine. An acoustic beam is transmitted upward through the water column, reflecting off the bottom of the sea ice and returning to the transducer. Ice thickness is estimated as the difference between the ship's depth (measured by pressure) and the acoustic range to the bottom of the ice estimated from the travel time of the sonar pulse. Digital recording systems can provide the return off the water-ice interface as well as returns that have penetrated the ice. Typically, only the first return from the ice hull is analyzed. Information regarding ice flow interstitial layers provides ice age information and may possibly be derived with the entire return signal. The approach being investigated is similar to that used in measuring bottom sediment layers and will involve measuring the echo level from the first interface, solving the reflection loss from that transmission, and employing reflection loss versus impedance mismatch to ascertain ice structure information.

  5. Properties of the Top Quark

    SciTech Connect

    Déliot, Frédéric; Hadley, Nicholas; Parke, Stephen; Schwarz, Tom

    2014-10-01

    The top quark is the heaviest known elementary particle, and it is often seen as a window to search for new physics processes in particle physics. A large program to study the top-quark properties has been performed both at the Tevatron and LHC colliders by the D0, CDF, ATLAS and CMS experiments. The most recent results are discussed in this article.

  6. Naturalness from a composite top?

    NASA Astrophysics Data System (ADS)

    Pierce, Aaron; Zhao, Yue

    2017-01-01

    We consider a theory with composite top quarks but an elementary Higgs boson. The hierarchy problem can be solved by supplementing TeV scale top compositeness with either supersymmetry or Higgs compositeness appearing at the multi-TeV scale. The Higgs boson couples to uncolored partons within the top quark. We study how this approach can give rise to a novel screening effect that suppresses production of the colored top partners at the LHC. Strong constraints arise from Z to overline{b}b , as well potentially from flavor physics. Independent of flavor considerations, current constraints imply a compositeness scale ≳ TeV; this implies that the model is likely tuned at the percent level. Four top quark production at the LHC is a smoking-gun probe of this scenario. New CP violation in D meson mixing is also possible.

  7. Buffer layer for thin film structures

    SciTech Connect

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2010-06-15

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  8. Buffer layer for thin film structures

    DOEpatents

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2006-10-31

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  9. Wave Engine Topping Cycle Assessment

    NASA Technical Reports Server (NTRS)

    Welch, Gerard E.

    1996-01-01

    The performance benefits derived by topping a gas turbine engine with a wave engine are assessed. The wave engine is a wave rotor that produces shaft power by exploiting gas dynamic energy exchange and flow turning. The wave engine is added to the baseline turboshaft engine while keeping high-pressure-turbine inlet conditions, compressor pressure ratio, engine mass flow rate, and cooling flow fractions fixed. Related work has focused on topping with pressure-exchangers (i.e., wave rotors that provide pressure gain with zero net shaft power output); however, more energy can be added to a wave-engine-topped cycle leading to greater engine specific-power-enhancement The energy addition occurs at a lower pressure in the wave-engine-topped cycle; thus the specific-fuel-consumption-enhancement effected by ideal wave engine topping is slightly lower than that effected by ideal pressure-exchanger topping. At a component level, however, flow turning affords the wave engine a degree-of-freedom relative to the pressure-exchanger that enables a more efficient match with the baseline engine. In some cases, therefore, the SFC-enhancement by wave engine topping is greater than that by pressure-exchanger topping. An ideal wave-rotor-characteristic is used to identify key wave engine design parameters and to contrast the wave engine and pressure-exchanger topping approaches. An aerodynamic design procedure is described in which wave engine design-point performance levels are computed using a one-dimensional wave rotor model. Wave engines using various wave cycles are considered including two-port cycles with on-rotor combustion (valved-combustors) and reverse-flow and through-flow four-port cycles with heat addition in conventional burners. A through-flow wave cycle design with symmetric blading is used to assess engine performance benefits. The wave-engine-topped turboshaft engine produces 16% more power than does a pressure-exchanger-topped engine under the specified topping

  10. Status of the top quark: Top production cross section and top properties

    SciTech Connect

    Boisvert, V.; /Rochester U.

    2006-08-01

    This report describes the latest cross section and property measurements associated with the top quark at the Tevatron Run II. The largest data sample used is 760 pb{sup -1} of integrated luminosity. Due to its large mass, the top quark might be involved in the process of electroweak symmetry breaking, making it a useful probe for signs of new physics.

  11. Laminated fabric as top electrode for organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Steim, R.; Chabrecek, P.; Sonderegger, U.; Kindle-Hasse, B.; Siefert, W.; Kroyer, T.; Reinecke, P.; Lanz, T.; Geiger, T.; Hany, R.; Nüesch, F.

    2015-05-01

    A simple lamination technique for conductive and semitransparent fabrics on top of organic photovoltaic cells is presented. Conductive fabrics consisted of metal wires woven in a fabric with polymeric fibers. The lamination of this conductive fabric with help of a high conductive poly(3,4-ethylenedioxythiophene) polystyrene sulfonate formulation results in well aligned low resistive metal wires as top electrode. Semitransparent flexible organic photovoltaic cells were processed with laminated fabrics as top electrode and sputtered layers of aluminum doped zinc oxide and Ag as bottom electrode. The organic photovoltaic cells showed similar performance when illuminated through the bottom or top electrode. Optical simulations were performed to investigate light scattering effects of the fabric. Results are very promising for photovoltaic and lightning devices as well as for all kinds of devices where semitransparent, highly conductive, and non-vacuum processed electrode materials are needed.

  12. PERSPECTIVE VIEW FROM SOUTH. BOARD SIDING, ROOF SHINGLES, AND TOP ...

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

    PERSPECTIVE VIEW FROM SOUTH. BOARD SIDING, ROOF SHINGLES, AND TOP LAYER OF BOARD DECKING WERE INSTALLED IN 1995. - Cataract Falls Bridge, Spanning Mill Creek, bypassed section of CR 279 (Cataract Falls Unit of Leiber State Recreation Area), Cataract, Owen County, IN

  13. Top of the World

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This panorama is one of the first that NASA's Spirit rover snapped upon reaching the summit of 'Husband Hill,' located in 'Columbia Hills' in Gusev Crater, Mars. It reveals the vast landscape to the east previously hidden behind the Columbia Hills. The rim of 'Thira Crater' frames the distant horizon some 15 kilometers (9.3 miles) away. The summit area is divided by a shallow saddle that slopes north (left) into an area called 'Tennessee Valley.' Large amounts of sandy material have been blown up the valley and across the saddle in the left-to-right direction, creating the rippled piles of sand seen in this image.

    The science team will examine bedrock and other materials in the summit area to determine their composition and the orientation of the rock layers. These and other observations will provide clues to how the rocks formed and how the hills were sculpted in the geologic past.

    This mosaic was taken by Spirit's panoramic camera, using the blue filter of its right eye.

  14. Properties of the top quark

    SciTech Connect

    Jung, A. W.

    2014-09-24

    Recent measurements of top-quark properties at the LHC and the Tevatron are presented. Most recent measurements of the top quark mass have been carried out by CMS using $19.7/$fb of $\\sqrt{s} = 8$ TeV data including the study of the dependence on event kinematics. ATLAS uses the full Run I data at $\\sqrt{s} = 7$ TeV for a "3D" measurement that significantly reduces systematic uncertainties. D0 employs the full Run II data using the matrix element method to measure the top quark mass with significantly reduced systematic uncertainties. Many different measurements of the top quark exist to date and the most precise ones per decay channel per experiment have been combined into the first world combination with a relative precision of 0.44%. Latest updates of measurements of production asymmetries include the measurement of the \\ttbar production asymmetry by D0 employing the full Run II data set, by CMS and ATLAS (including the polarization of the top quark) employing both the full data set at $\\sqrt{s} = 7$ TeV. CMS uses the full $\\sqrt{s} = 8$ TeV data to measure the top quark polarization in single top production, the ratio ${\\cal R}$ of the branching fractions ${\\cal B}(t \\rightarrow Wb) / {\\cal B}(t \\rightarrow Wq)$ and to search for flavor changing neutral currents. The results from all these measurements agree well with their respective Standard Model expectation.

  15. Layers Inside 'Endurance'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This view of rock layers exposed in the upper portion of the inner slope of 'Endurance Crater' was captured by the navigation camera on NASA's Mars Exploration Rover Opportunity from the rover's position inside the crater during Opportunity's 134th sol on June 9, 2004. Scientists and engineers are assessing possible targets and routes among these rocks. The view is looking down into the crater, so the layers at the top of the image lie lower in the crater than the rocks in the foreground.

  16. Australia's Next Top Fraction Model

    ERIC Educational Resources Information Center

    Gould, Peter

    2013-01-01

    Peter Gould suggests Australia's next top fraction model should be a linear model rather than an area model. He provides a convincing argument and gives examples of ways to introduce a linear model in primary classrooms.

  17. Trajectory correction propulsion for TOPS

    NASA Technical Reports Server (NTRS)

    Long, H. R.; Bjorklund, R. A.

    1972-01-01

    A blowdown-pressurized hydrazine propulsion system was selected to provide trajectory correction impulse for outer planet flyby spacecraft as the result of cost/mass/reliability tradeoff analyses. Present hydrazine component and system technology and component designs were evaluated for application to the Thermoelectric Outer Planet Spacecraft (TOPS); while general hydrazine technology was adequate, component design changes were deemed necessary for TOPS-type missions. A prototype hydrazine propulsion system was fabricated and fired nine times for a total of 1600 s to demonstrate the operation and performance of the TOPS propulsion configuration. A flight-weight trajectory correction propulsion subsystem (TCPS) was designed for the TOPS based on actual and estimated advanced components.

  18. Forum outlines top emerging technologies

    NASA Astrophysics Data System (ADS)

    Extance, Andy

    2015-04-01

    Additive manufacturing, next-generation robotics, "sense and avoid" drones that fly themselves, artificial intelligence and "neuromorphic" computing have all made it into the World Economic Forum's top 10 emerging technologies for 2015.

  19. Top 10 Products of 2011

    ERIC Educational Resources Information Center

    American School & University, 2011

    2011-01-01

    In 2011, American School & University (AS&U) showcased some of the hottest products in the industry. This article presents the top ten most requested products as determined by readers. The top one on the list is the Bulb crusher which can cut recycling costs by 50%, can hold 1,350 4-foot lamps in a single 55-gallon drum, can crush a 4-foot lamp in…

  20. Low hysteresis FeMn-based top spin valve.

    PubMed

    Ustinov, V V; Krinitsina, T P; Milyaev, M A; Naumova, L I; Proglyado, V V

    2012-09-01

    FeMn-based top spin valves Ta/[FeNi/CoFe]/Cu/CoFe/FeMn/Ta with different Cu and FeMn layers thicknesses were prepared by DC magnetron sputtering at room temperature. It was shown that low field hysteresis due to free layer magnetization reversal can be reduced down to (0.1 divided by 0.2) Oe keeping the GMR ratio higher 8% by using both layers thicknesses optimization and non-collinear geometry of magnetoresistance measurements. Dependence of low field hysteresis and GMR ratio on the angle between applied magnetic field and pinning direction are presented.

  1. Uncovering the single top: observation of electroweak top quark production

    SciTech Connect

    Benitez, Jorge Armando

    2009-01-01

    The top quark is generally produced in quark and anti-quark pairs. However, the Standard Model also predicts the production of only one top quark which is mediated by the electroweak interaction, known as 'Single Top'. Single Top quark production is important because it provides a unique and direct way to measure the CKM matrix element Vtb, and can be used to explore physics possibilities beyond the Standard Model predictions. This dissertation presents the results of the observation of Single Top using 2.3 fb-1 of Data collected with the D0 detector at the Fermilab Tevatron collider. The analysis includes the Single Top muon+jets and electron+jets final states and employs Boosted Decision Tress as a method to separate the signal from the background. The resulting Single Top cross section measurement is: (1) σ(p$\\bar{p}$→ tb + X, tqb + X) = 3.74-0.74+0.95 pb, where the errors include both statistical and systematic uncertainties. The probability to measure a cross section at this value or higher in the absence of signal is p = 1.9 x 10-6. This corresponds to a standard deviation Gaussian equivalence of 4.6. When combining this result with two other analysis methods, the resulting cross section measurement is: (2) σ(p$\\bar{p}$ → tb + X, tqb + X) = 3.94 ± 0.88 pb, and the corresponding measurement significance is 5.0 standard deviations.

  2. Electrical Discharges in the Overshooting Tops of Five Storms

    NASA Astrophysics Data System (ADS)

    MacGorman, D. R.; Elliott, M.

    2013-12-01

    Individual electrical discharges detected by VHF Lightning Mapping Arrays (LMAs) in the overshooting tops of strong storms typically occur continually at rates of roughly 1 - 10 per second and do not appear to cluster systematically in time or space as flashes. This study analyzed discharges relative to S-band polarimetric radar data and to GOES infrared imagery in the overshooting tops of five storms ranging from moderately strong multicell storms to supercell storms. Although the density of VHF sources in overshooting tops was much less than the maximum densities below the level of neutral bouyancy, the overshooting top typically contained a secondary maximum of density. The onset of discharges in an overshooting top corresponded to an increase in the maximum magnitude and height of reflectivity as the top substantially penetrated the level of neutral bouyancy. Once the discharges began, most were within reflectivities of at least 18 dBZ and formed a dome having geometry similar to that of the dome in reflectivity. Discharges persisted for approximately as long as the reflectivity dome persisted and could last anywhere from a few minutes for short-lived overshooting tops to a few hours for cases with an overlapping series of overshooting tops produced by a succession of updraft pulses. The 99.99th percentile in the height of VHF sources was well correlated (correlation coefficient of at least 0.8) with the height of 18 and 30 dBZ, and the timing of variations in height of these parameters agreed well. We suggest the discharges are caused by turbulent cells bringing negative screening layer charge close to positive charge in the updraft core. The onset of discharges in an overshooting top preceded the detection of overshooting tops in satellite imagery. The poorer performance probably was the result of the poorer spatiotemporal resolution of infrared cloud-top imagery in the present GOES constellation. Severe weather was either imminent or occurring when

  3. Transparent indium zinc oxide top cathode prepared by plasma damage-free sputtering for top-emitting organic light-emitting diodes

    SciTech Connect

    Kim, Han-Ki; Lee, Kyu-Sung; Kwon, J.H.

    2006-01-02

    We report on plasma damage-free sputtering of an indium zinc oxide (IZO) top cathode layer for top-emitting organic light-emitting diodes (TOLEDs) by using a box cathode sputtering (BCS) technique. A sheet resistance of 42.6 {omega}/cm and average transmittance above 88% in visible range were obtained even in IZO layers deposited by BCS at room temperature. The TOLED with the IZO top cathode layer shows electrical characteristics and lifetime comparable to a TOLED with only thermally evaporated Mg-Ag cathode. In particular, it is shown that the TOLED with the IZO top cathode film shows very low leakage current density of 1x10{sup -5} mA cm{sup 2} at reverse bias of -6 V. This suggests that there is no plasma damage caused by the bombardment of energetic particles during IZO sputtering using the BCS system.

  4. SW New Mexico Oil Well Formation Tops

    SciTech Connect

    Shari Kelley

    2015-10-21

    Rock formation top picks from oil wells from southwestern New Mexico from scout cards and other sources. There are differing formation tops interpretations for some wells, so for those wells duplicate formation top data are presented in this file.

  5. The multiple layer solar collector

    NASA Astrophysics Data System (ADS)

    Kenna, J. P.

    1983-01-01

    An analytical model is developed for obtaining numerical solutions for differential equations describing the performance of separate layers in a multiple layer solar collector. The configurations comprises heat transfer fluid entering at the top of the collector and travelling down through several layers. A black absorber plate prevents reemission of thermal radiation. The overall performance is shown to depend on the number of layers, the heat transfer coefficient across each layer, and the absorption properties of the working fluid. It is found that the multiple layer system has a performance inferior to that of flat plate selective surface collectors. Air gaps insulating adjacent layers do not raise the efficiency enough to overcome the relative deficiency.

  6. Dynamics of a cliff top dune

    NASA Astrophysics Data System (ADS)

    Rasmussen, K. R.

    2012-12-01

    beds of coarse sand are missing the cliff is steep and dunes are absent at the cliff top. On the other hand when floes are present then some parts of the cliff are less steep and where sand is abundant cliff top dunes seem to be abundant, too. In order to investigate how flow conditions at the cliff front responds to its geometry, scale models of the cliff front approximately 1:10, but with different steepness have been tested in a boundary layer wind tunnel. All runs have been made with proper roughness scaling and besides a variation in their longitudinal profiles some variation in their transverse profiles has also been tested. The surface-near flow has been mapped with high resolution 2-D laser-Doppler profiling, and one of the important aims is to demonstrate the interaction between sediment and geological structure on one side and flow and dune state on the other side. A particular aim is to investigate if and how the separation bubble may have a profound control on mobilization and transport of sediment.

  7. Fabrication of three dimensional diamond ultraviolet photodetector through down-top method

    NASA Astrophysics Data System (ADS)

    Liu, Zhangcheng; Ao, Jin-Ping; Li, Fengnan; Wang, Wei; Wang, Jingjing; Zhang, Jingwen; Wang, Hong-Xing

    2016-10-01

    Three dimensional diamond ultraviolet (UV) photodetector have been fabricated on diamond epitaxial layer through down-top approach, where diamond epitaxial layer was grown between metal electrodes. A thin diamond epitaxial layer was first grown on high-pressure high-temperature single crystal diamond substrate. Then, the diamond epitaxial layer was covered by interdigitated tungsten electrodes. Furthermore, another diamond epitaxial layer was grown on uncovered area. At last, UV-Ozone treatment was used to oxidize the surface. The optoelectronic performance of the photodetector was characterized, exhibiting a large responsivity and a repeatable transient response behavior. Moreover, down-top process is beneficial for the electrode conductivity stability. Also, an ohmic contact could be formed between tungsten and diamond during growth. The results indicate that down-top process is an efficient way for fabrication of three dimensional diamond photodetectors.

  8. Generalized approach to design multi-layer stacks for enhanced optical detectability of ultrathin layers

    NASA Astrophysics Data System (ADS)

    Hutzler, A.; Matthus, C. D.; Rommel, M.; Frey, L.

    2017-01-01

    The optical detectability of ultrathin conductive films (down to one atomic layer) can be enhanced by choosing distinct layer-stacks. A simple analytical approach using the transfer matrix method is applied for calculating the reflectance of arbitrary multi-layer stack systems with and without the ultrathin layer of interest on top in a wide wavelength range, including both the visible spectrum and the ultraviolet spectrum. Then, the detectability defined by the Michelson contrast was calculated. Performing these calculations for thickness variations of the individual layers in the stack allows determining optimum layer thicknesses, e.g., maximum overall contrast or maximum contrast for a given wavelength. To demonstrate the validity of the methodology, two thin film stacks were investigated, which use p-type silicon as a substrate material and partially covered by a single-layer graphene as a top layer. For each stack, two samples with different layer thicknesses were fabricated and their experimentally determined reflectance was compared to the calculated values. The first system consists of a single SiO2 layer with a thickness of 147 nm and 304 nm, respectively, and the second is a double layer stack consisting of a Si3N4 layer with a thickness of 54 nm and 195 nm, respectively, on top of an 11 nm SiO2 film. The Michelson contrast of single-layer graphene flakes on the latter layer stacks becomes very high (absolute value of more than 0.3) in the visible wavelength range. Additionally, in the UV-B range a large difference in the reflection of selected SiO2 layer thicknesses on silicon substrates with and without single-layer graphene on top is found with a decrease in the measured reflectance of up to 33%. The measured and calculated values showed a high conformity suggesting this approach usable for the calculation of reflectance and transmittance properties of arbitrary layer stack systems including thin conductive layers.

  9. Training Top 10 Hall of Fame

    ERIC Educational Resources Information Center

    Training, 2012

    2012-01-01

    Microsoft Corporation and SCC Soft Computer are the newest inductees into the Training Top 10 Hall of Fame, joining the ranks of the 11 companies named to the hall since its inception in 2008 (Wyeth Pharmaceuticals subsequently was acquired by Pfizer Inc. in 2009). These 11 companies held Top 10 spots in the Training Top 50, Top 100, and now Top…

  10. Top Mass Measurements at the Tevatron

    SciTech Connect

    Wang, M.H.L.S.; /Fermilab

    2009-04-01

    We present the latest measurements of the top quark mass from the Tevatron. The different top decay channels and measurement techniques used for these results are also described. The world average of the top quark mass based on some of these new results combined with previous results is m{sub top} = 172.6 {+-} 1.4 GeV.

  11. Adjustable magneto-optical isolators with flat-top responses.

    PubMed

    Zamani, Mehdi; Ghanaatshoar, Majid

    2012-10-22

    In order to construct flat-top magneto-optical isolators (MOIs), we have performed a theoretical study on the case of transmission-type one-dimensional magnetophotonic crystals (MPCs). We have introduced high performance MPC structures with flat-top responses and with the capability of adjusting to perfect MOIs. The adjustment is carried out by tuning the applied magnetic field. All introduced MOIs are sufficiently thin with acceptable transmission bandwidth. In the best case, we have achieved a 19.42 μm-thick perfect MOI with the flat-top width of 7.2 nm. For practical purposes, we have also considered the influence of the error in thickness of individual layers on the operational parameters of the MOIs and investigated the possibility of compensating the deviations by the magnetic adjustment.

  12. Kowalevski top in quantum mechanics

    SciTech Connect

    Matsuyama, A.

    2013-09-15

    The quantum mechanical Kowalevski top is studied by the direct diagonalization of the Hamiltonian. The spectra show different behaviors depending on the region divided by the bifurcation sets of the classical invariant tori. Some of these spectra are nearly degenerate due to the multiplicity of the invariant tori. The Kowalevski top has several symmetries and symmetry quantum numbers can be assigned to the eigenstates. We have also carried out the semiclassical quantization of the Kowalevski top by the EBK formulation. It is found that the semiclassical spectra are close to the exact values, thus the eigenstates can be also labeled by the integer quantum numbers. The symmetries of the system are shown to have close relations with the semiclassical quantum numbers and the near-degeneracy of the spectra. -- Highlights: •Quantum spectra of the Kowalevski top are calculated. •Semiclassical quantization is carried out by the EBK formulation. •Quantum states are labeled by the semiclassical integer quantum numbers. •Multiplicity of the classical torus makes the spectra nearly degenerate. •Symmetries, quantum numbers and near-degenerate spectra are closely related.

  13. The Top Theological Degree Producers

    ERIC Educational Resources Information Center

    Diverse: Issues in Higher Education, 2012

    2012-01-01

    Each year, "Diverse: Issues in Higher Education" publishes a list of the Top 100 producers of associate, bachelor's and graduate degrees awarded to minority students based on research conducted by Dr. Victor M. H. Borden, professor of educational leadership and policy studies at Indiana University Bloomington. This year, for the first…

  14. "Top School Problems" Are Myths.

    ERIC Educational Resources Information Center

    Males, Mike

    1992-01-01

    A well-known "study" comparing the top school problems of 1940 (talking and gum chewing) with those of 1987 (drug abuse, pregnancy, and violence) is nonexistent. In 1940, 49 percent of all youth did not finish high school, 37,000 teenagers died from violence or disease, and 335,000 teens gave birth. Educators should discount pastoral…

  15. China offshore has top priority

    SciTech Connect

    Cornitius, T.A.

    1983-11-01

    Joint venture development of offshore petroleum reserves has top priority in the mammoth effort to modernize the People's Republic of China. While the country works to overcome a critical shortage of skilled personnel, export of oil, coal, consumer goods, and metals will finance technological imports.

  16. Observation of the Top Quark

    DOE R&D Accomplishments Database

    Kim, S. B.

    1995-08-01

    Top quark production is observed in{bar p}p collisions at{radical}s= 1.8 TeV at the Fermilab Tevatron. The Collider Detector at Fermilab (CDF) and D{O} observe signals consistent with t{bar t} to WWb{bar b}, but inconsistent with the background prediction by 4.8{sigma} (CDF), 4.6a (D{O}). Additional evidence for the top quark Is provided by a peak in the reconstructed mass distribution. The kinematic properties of the excess events are consistent with the top quark decay. They measure the top quark mass to be 176{plus_minus}8(stat.){plus_minus}10(sys.) GeV/c{sup 2} (CDF), 199{sub -21}{sup+19}(stat.){plus_minus}22(sys.) GeV/c{sup 2} (D{O}), and the t{bar t} production cross section to be 6.8{sub -2.4}{sup+3.6}pb (CDF), 6.4{plus_minus}2.2 pb (D{O}).

  17. Kinematic top analyses at CDF

    SciTech Connect

    Cobal-Grassman, M.; CDF Collaboration

    1996-01-01

    We present an update of the top quark analysis using kinematic techniques in {rho}{ovr string {rho}} collisions at {radical}s = 1.8 TeV with the Collider Detector at Fermilab (CDF). We reported before on a study which used 19.3 pb{sup -1} of data from the 1992-93 collider run, but now we use a larger data sample of 67 pb{sup -1}. First, we analyze the total transverse energy of the hard collision in W+{ge}3 jet events, showing the likely presence of a t{ovr string t} component in the event sample. Next, we compare in more detail the kinematic structure of W+{ge}3 jet events with expectations for top pair production and with background processes, predominantly direct W+ jet production. We again find W+{ge}3 jet events which cannot be explained in terms of background, but show kinematic features as expected from top. These events also show evidence for beauty quarks. The findings confirm the observation of top events made earlier in the data of the 1992-93 collider run.

  18. The Top STEM Degree Producers

    ERIC Educational Resources Information Center

    Diverse: Issues in Higher Education, 2012

    2012-01-01

    This article presents a list of the top Science, Technology, Engineering, and Mathematics (STEM) degree producers in the U.S. This list is broken down into seven categories: (1) Total Minority Research/Scholarship and Other Doctoral: Mathematics and Statistics; (2) Total Minority Bachelors: Biological and Biomedical Sciences; (3) Total Minority…

  19. Two-layer anti-reflection strategies for implant applications

    NASA Astrophysics Data System (ADS)

    Guerrero, Douglas J.; Smith, Tamara; Kato, Masakazu; Kimura, Shigeo; Enomoto, Tomoyuki

    2006-03-01

    A two-layer bottom anti-reflective coating (BARC) concept in which a layer that develops slowly is coated on top of a bottom layer that develops more rapidly was demonstrated. Development rate control was achieved by selection of crosslinker amount and BARC curing conditions. A single-layer BARC was compared with the two-layer BARC concept. The single-layer BARC does not clear out of 200-nm deep vias. When the slower developing single-layer BARC was coated on top of the faster developing layer, the vias were cleared. Lithographic evaluation of the two-layer BARC concept shows the same resolution advantages as the single-layer system. Planarization properties of a two-layer BARC system are better than for a single-layer system, when comparing the same total nominal thicknesses.

  20. Top Jets at the LHC

    SciTech Connect

    Almeida, L.G.; Lee, S.J.; Perez, G.; Sung, I.; Virzi, J.

    2008-10-06

    We investigatethe reconstruction of high pT hadronically-decaying top quarksat the Large Hadron Collider. One of the main challenges in identifying energetictop quarks is that the decay products become increasingly collimated. This reducesthe efficacy of conventional reconstruction methods that exploit the topology of thetop quark decay chain. We focus on the cases where the decay products of the topquark are reconstructed as a single jet, a"top-jet." The most basic"top-tag" methodbased on jet mass measurement is considered in detail. To analyze the feasibility ofthe top-tagging method, both theoretical and experimental aspects of the large QCDjet background contribution are examined. Based on a factorization approach, wederive a simple analytic approximation for the shape of the QCD jet mass spectrum.We observe very good agreement with the Monte Carlo simulation. We consider high pT tt bar production in the Standard Model as an example, and show that our theoretical QCD jet mass distributions can efficiently characterize the background via sideband analyses. We show that with 25 fb-1 of data, our approach allows us to resolve top-jets with pT _> 1 TeV, from the QCD background, and about 1.5 TeV top-jets with 100 fb-1, without relying on b-tagging. To further improve the significancewe consider jet shapes (recently analyzed in 0807.0234 [hep-ph]), which resolve thesubstructure of energy flow inside cone jets. A method of measuring the top quarkpolarization by using the transverse momentum of the bottom quark is also presented.The main advantages of our approach are: (i) the mass distributions are driven byfirst principle calculations, instead of relying solely on Monte Carlo simulation; (ii) for high pT jets (pT _> 1 TeV), IR-safe jet shape variables are robust against detectorresolution effects. Our analysis can be applied to other boosted massive particlessuch as the electroweak gauge bosons and the Higgs.

  1. Impact of water and top-coats on lithographic performance in 193-nm immersion lithography

    NASA Astrophysics Data System (ADS)

    Kishimura, Shinji; Gronheid, Roel; Ercken, Monique; Maenhoudt, Mireille; Matsuo, Takahiro; Endo, Masayuki; Sasago, Masaru

    2005-05-01

    We have investigated the impact of water and top-coats on the resist in water immersion lithography by analyzing the dissolution behavior and the film constitution. We used a resist development analyzer (RDA) and a quartz crystal microbalance (QCM) to study the dissolution behavior. The film constitution was studied through the gradient shaving preparation (GSP) method in combination with TOF-SIMS. The GSP/TOF-SIMS method reveals the constitution of a top-coat/resist film. We found that, in a resist, the photo acid generator (PAG) anion at a depth of about 30 nm from the surface leached into water and a surface insoluble layer formed during immersion. The estimated amount of leaching was about 5% of the original content. The formation of an intermixing layer with a low dissolution rate was observed for some top-coat and resist combinations. The thickness of the intermixing layer and the formation behavior were made clear. We believe the intermixing layer was caused by the top-coat solvent eluting resist components. In a top-coat, a PAG existed within the top-coat and the PAG anion leached into the water. Top-coats blocked gaseous decomposed products from the resist film during PEB. These results are useful for estimating patterning characteristics and the defectivity due to materials for actual immersion exposure.

  2. Thin layer composite unimorph ferroelectric driver and sensor

    NASA Technical Reports Server (NTRS)

    Hellbaum, Richard F. (Inventor); Bryant, Robert G. (Inventor); Fox, Robert L. (Inventor); Jalink, Jr., Antony (Inventor); Rohrbach, Wayne W. (Inventor); Simpson, Joycelyn O. (Inventor)

    2004-01-01

    A method for forming ferroelectric wafers is provided. A prestress layer is placed on the desired mold. A ferroelectric wafer is placed on top of the prestress layer. The layers are heated and then cooled, causing the ferroelectric wafer to become prestressed. The prestress layer may include reinforcing material and the ferroelectric wafer may include electrodes or electrode layers may be placed on either side of the ferroelectric layer. Wafers produced using this method have greatly improved output motion.

  3. Properties of the Top Quark

    SciTech Connect

    Wicke, Daniel; /Wuppertal U., Dept. Math.

    2009-08-01

    The aim of particle physics is the understanding of elementary particles and their interactions. The current theory of elementary particle physics, the Standard Model, contains twelve different types of fermions which (neglecting gravity) interact through the gauge bosons of three forces. In addition a scalar particle, the Higgs boson, is needed for theoretical consistency. These few building blocks explain all experimental results found in the context of particle physics, so far. Nevertheless, it is believed that the Standard Model is only an approximation to a more complete theory. First of all the fourth known force, gravity, has withstood all attempts to be included until now. Furthermore, the Standard Model describes several features of the elementary particles like the existence of three families of fermions or the quantisation of charges, but does not explain these properties from underlying principles. Finally, the lightness of the Higgs boson needed to explain the symmetry breaking is difficult to maintain in the presence of expected corrections from gravity at high scales. This is the so called hierarchy problem. In addition astrophysical results indicate that the universe consists only to a very small fraction of matter described by the Standard Model. Large fractions of dark energy and dark matter are needed to describe the observations. Both do not have any correspondence in the Standard Model. Also the very small asymmetry between matter and anti-matter that results in the observed universe built of matter (and not of anti-matter) cannot be explained until now. It is thus an important task of experimental particle physics to test the predictions of the Standard Model to the best possible accuracy and to search for deviations pointing to necessary extensions or modifications of our current theoretical understanding. The top quark was predicted to exist by the Standard Model as the partner of the bottom quark. It was first observed in 1995 by the

  4. Buffer layer engineering on graphene via various oxidation methods for atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Takahashi, Nobuaki; Nagashio, Kosuke

    2016-12-01

    The integration of a high-k oxide on graphene using atomic layer deposition requires an electrically reliable buffer layer. In this study, Y was selected as the buffer layer due to its highest oxidation ability among the rare-earth elements, and various oxidation methods (atmospheric, and high-pressure O2 and ozone annealing) were applied to the Y metal buffer layer. By optimizing the oxidation conditions of the top-gate insulator, we successfully improved the capacitance of the top gate Y2O3 insulator and demonstrated a large I on/I off ratio for bilayer graphene under an external electric field.

  5. Attitude propulsion technology for TOPS

    NASA Technical Reports Server (NTRS)

    Moynihan, P. I.

    1972-01-01

    The thermoelectric outer planet spacecraft (TOPS) attitude propulsion subsystem (APS) effort is discussed. It includes the tradeoff rationale that went into the selection of an anhydrous hydrazine baseline system, followed by a discussion of the 0.22 N thruster and its integration into a portable, self-contained propulsion module that was designed, developed, and man rated to support the TOPS single-axis attitude control tests. The results of a cold-start feasibility demonstration with a modified thruster are presented. A description of three types of 0.44 thrusters that were procured for in-house evaluation is included along with the results of the test program. This is followed by a description of the APS feed system components, their evaluations, and a discussion of an evaluation of elastomeric material for valve seat seals. A list of new technology items which will be of value for application to future systems of this type is included.

  6. Top decays in extended models

    SciTech Connect

    Gaitan, R.; Miranda, O. G.; Cabral-Rosetti, L. G.

    2009-04-20

    Top quark decays are interesting as a mean to test the Standard Model (SM) predictions. The Cabbibo-Kobayashi-Maskawa (CKM)-suppressed process t{yields}cWW, and the rare decays t{yields}cZ, t{yields}H{sup 0}+c, and t{yields}c{gamma} an excellent window to probe the predictions of theories beyond the SM. We evaluate the flavor changing neutral currents (FCNC) decay t{yields}H{sup 0}+c in the context of Alternative Left-Right symmetric Models (ALRM) with extra isosinglet heavy fermions; the FCNC decays may place at tree level and are only supressed by the mixing between ordinary top and charm quarks. We also comment on the decay process t{yields}c+{gamma}, which involves radiative corrections.

  7. Thermoelectric Outer Planets Spacecraft (TOPS)

    NASA Technical Reports Server (NTRS)

    1973-01-01

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

  8. Top quark results at CDF

    SciTech Connect

    Leone, S.; CDF Collaboration

    1996-08-01

    We present the latest results on the top quark obtained by the CDF experiment using a data sample of about 110 {ital pb}{sup -1} collected at the Fermilab Tevatron collider. We briefly describe the candidate events selection and then discuss the production cross section determination and the mass measurement. The study of two new decay channels (all hadronic and ``tau dilepton``) is also reported.

  9. Buffer layers on metal alloy substrates for superconducting tapes

    DOEpatents

    Jia, Quanxi; Foltyn, Stephen R.; Arendt, Paul N.; Groves, James R.

    2004-10-05

    An article including a substrate, at least one intermediate layer upon the surface of the substrate, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the at least one intermediate layer, and a layer of a SrRuO.sub.3 buffer material upon the oriented cubic oxide material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon the layer of a SrRuO.sub.3 buffer material layer. With a HTS top-layer of YBCO upon at least one layer of the SrRuO.sub.3 buffer material in such an article, J.sub.c 's of up to 1.3.times.10.sup.6 A/cm.sup.2 have been demonstrated with projected I.sub.c 's of over 200 Amperes across a sample 1 cm wide.

  10. Observation of the Top Quark

    SciTech Connect

    Abachi, S.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adam, I.; Adams, D.L.; Adams, M.; Ahn, S.; Aihara, H.; Aihara, H.; Alitti, J.; Alvarez, G.; Alves, G.A.; Amidi, E.; Amos, N.; Anderson, E.W.; Aronson, S.H.; Astur, R.; Avery, R.E.; Balamurali, V.; Balderston, J.; Baldin, B.; Bantly, J.; Bartlett, J.F.; Bazizi, K.; Bendich, J.; Beri, S.B.; Bertram, I.; Bezzubov, V.A.; Bhat, P.C.; Bhatnagar, V.; Bhattacharjee, M.; Bischoff, A.; Biswas, N.; Blazey, G.; Blessing, S.; Boehnlein, A.; Bojko, N.I.; Borcherding, F.; Borders, J.; Boswell, C.; Brandt, A.; Brock, R.; Bross, A.; Buchholz, D.; Burtovoi, V.S.; Butler, J.M.; Casey, D.; Castilla-Valdez, H.; Chakraborty, D.; Chang, S.; Chekulaev, S.V.; Chen, L.; Chen, W.; Chevalier, L.; Chopra, S.; Choudhary, B.C.; Christenson, J.H.; Chung, M.; Claes, D.; Clark, A.R.; Cobau, W.G.; Cochran, J.; Cooper, W.E.; Cretsinger, C.; Cullen-Vidal, D.; Cummings, M.; Cutts, D.; Dahl, O.I.; De, K.; Demarteau, M.; Demina, R.; Denisenko, K.; Denisenko, N.; Denisov, D.; Denisov, S.P.; Dharmaratna, W.; Diehl, H.T.; Diesburg, M.; Di Loreto, G.; Dixon, R.; Draper, P.; Drinkard, J.; Ducros, Y.; Dugad, S.R.; Durston-Johnson, S.; Edmunds, D.; Efimov, A.O.; Ellison, J.; Elvira, V.D.; Engelmann, R.; Eno, S.; Eppley, G.; Ermolov, P.; Eroshin, O.V.; Evdokimov, V.N.; Fahey, S.; Fahland, T.; Fatyga, M.; Fatyga, M.K.; Featherly, J.; Feher, S.; Fein, D.; Ferbel, T.; Finocchiaro, G.; Fisk, H.E.; Fisyak, Y.; Flattum, E.; Forden, G.E.; Fortner, M.; Frame, K.C.; Franzini, P.; Fredriksen, S.; Fuess, S.; Galjaev, A.N.; Gallas, E.; Gao, C.S.; Gao, S.; Geld, T.L.; Genik, R.J. II; Genser, K.; Gerber, C.E.; Gibbard, B.; Glaubman, M.; Glebov, V.; Glenn, S.; Glicenstein, J.F.; Gobbi, B.; Goforth, M.; Goldschmidt, A.; Gomez, B.; Goncharov, P.I.; Gordon, H.; Goss, L.T.; Graf, N.; Grannis, P.D.; Green, D.R.; Green, J.; Greenlee, H.; Griffin, G.; Grossman, N.; Grudberg, P.; Gruenendahl, S.; Guida, J.A.; Guida, J.M.; Guryn, W.; Gurzhiev, S.N.; Gutnikov, Y.E.

    1995-04-03

    The D0 Collaboration reports on a search for the standard model top quark in {ital p{bar p}} collisions at {radical}{ital s}=1.8TeV at the Fermilab Tevatron with an integrated luminosity of approximately 50pb{sup {minus}1}. We have searched for {ital t{bar t}} production in the dilepton and single-lepton decay channels with and without tagging of {ital b}-quark jets. We observed 17 events with an expected background of 3.8{plus_minus}0.6 events. The probability for an upward fluctuation of the background to produce the observed signal is 2{times}10{sup {minus}6} (equivalent to 4.6 standard deviations). The kinematic properties of the excess events are consistent with top quark decay. We conclude that we have observed the top quark and measured its mass to be 199{sub {minus}21}{sup +19} (stat) {plus_minus}22 (syst) GeV/{ital c}{sup 2} and its production cross section to be 6.4{plus_minus}2.2pb.

  11. Layers and Erosion and more Layers

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 4 November 2003

    This image is located within a set of eroded layered rocks known as the Medusae Fossae Formation. Careful inspection of this image reveals four separate layers. Starting at the bottom of the image, as well as the bottom of the sequence of layers, is a somewhat hilly, cratered plain. Above that is a mud or lava flow with a lobate edge that is characteristic of fluid flow. Above that is a layer with a spectacular rayed crater. This layer shows linear erosional patterns that are probably caused by persistent wind abrasion, typical of rocks in this area. And finally, a more blocky unit lies on top, mostly eroded away.

    Image information: VIS instrument. Latitude 3.6, Longitude 218.6 East (141.4 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  12. Top quark studies at hadron colliders

    SciTech Connect

    Sinervo, P.K.

    1997-01-01

    The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and DO Collaborations are reviewed, including the top quark cross section, mass, branching fractions, and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented.

  13. Recent Top Properties Measurements at CDF

    SciTech Connect

    Chiarelli, Giorgio

    2014-11-26

    We present the most recent CDF results on the measurements of the decay and production vertex of the top-quark. New results on forward-backward asymmetry in top-antitop events are presented. Also, recent measurements of the branching fractions of top-quark are discussed. Finally, measurements in single top events, where top-quark is produced through electroweak processes, are presented. Despite the much larger number of top events collected at the LHC, due to the symmetric initial state and the better signal-to-background ratio in specific channels, some results will be lasting heritage of the Tevatron.

  14. Flexible logic circuits based on top-gate thin film transistors with printed semiconductor carbon nanotubes and top electrodes

    NASA Astrophysics Data System (ADS)

    Xu, Weiwei; Liu, Zhen; Zhao, Jianwen; Xu, Wenya; Gu, Weibing; Zhang, Xiang; Qian, Long; Cui, Zheng

    2014-11-01

    In this report printed thin film transistors and logic circuits on flexible substrates are reported. The top-gate thin film transistors were made of the sorted semiconducting single-walled carbon nanotubes (sc-SWCNTs) ink as channel material and printed silver lines as top electrodes and interconnect. 5 nm HfOx thin films pre-deposited on PET substrates by atomic layer deposition (ALD) act as the adhesion layers to significantly improve the immobilization efficiency of sc-SWCNTs and environmental stability. The immobilization mechanism was investigated in detail. The flexible partially-printed top-gate SWCNT TFTs display ambipolar characteristics with slightly strong p-type when using 50 nm HfOx thin films as dielectric layer, as well as the encapsulation layer by atomic layer deposition (ALD) at 120 °C. The hole mobility, on/off ratio and subthreshold swing (SS) are ~46.2 cm2 V-1 s-1, 105 and 109 mV per decade, respectively. Furthermore, partially-printed TFTs show small hysteresis, low operating voltage (2 V) and high stability in air. Flexible partially-printed inverters show good performance with voltage gain up to 33 with 1.25 V supply voltage, and can work at 10 kHz. The frequency of flexible partially-printed five-stage ring oscillators can reach 1.7 kHz at supply voltages of 2 V with per stage delay times of 58.8 μs. This work paves a way to achieve printed SWCNT advanced logic circuits and systems on flexible substrates.In this report printed thin film transistors and logic circuits on flexible substrates are reported. The top-gate thin film transistors were made of the sorted semiconducting single-walled carbon nanotubes (sc-SWCNTs) ink as channel material and printed silver lines as top electrodes and interconnect. 5 nm HfOx thin films pre-deposited on PET substrates by atomic layer deposition (ALD) act as the adhesion layers to significantly improve the immobilization efficiency of sc-SWCNTs and environmental stability. The immobilization mechanism

  15. Flexible logic circuits based on top-gate thin film transistors with printed semiconductor carbon nanotubes and top electrodes.

    PubMed

    Xu, Weiwei; Liu, Zhen; Zhao, Jianwen; Xu, Wenya; Gu, Weibing; Zhang, Xiang; Qian, Long; Cui, Zheng

    2014-12-21

    In this report printed thin film transistors and logic circuits on flexible substrates are reported. The top-gate thin film transistors were made of the sorted semiconducting single-walled carbon nanotubes (sc-SWCNTs) ink as channel material and printed silver lines as top electrodes and interconnect. 5 nm HfOx thin films pre-deposited on PET substrates by atomic layer deposition (ALD) act as the adhesion layers to significantly improve the immobilization efficiency of sc-SWCNTs and environmental stability. The immobilization mechanism was investigated in detail. The flexible partially-printed top-gate SWCNT TFTs display ambipolar characteristics with slightly strong p-type when using 50 nm HfO(x) thin films as dielectric layer, as well as the encapsulation layer by atomic layer deposition (ALD) at 120 °C. The hole mobility, on/off ratio and subthreshold swing (SS) are ∼ 46.2 cm(2) V(-1) s(-1), 10(5) and 109 mV per decade, respectively. Furthermore, partially-printed TFTs show small hysteresis, low operating voltage (2 V) and high stability in air. Flexible partially-printed inverters show good performance with voltage gain up to 33 with 1.25 V supply voltage, and can work at 10 kHz. The frequency of flexible partially-printed five-stage ring oscillators can reach 1.7 kHz at supply voltages of 2 V with per stage delay times of 58.8 μs. This work paves a way to achieve printed SWCNT advanced logic circuits and systems on flexible substrates.

  16. The turbulent wall jet: a triple-layered structure and incomplete similarity.

    PubMed

    Barenblatt, G I; Chorin, A J; Prostokishin, V M

    2005-06-21

    We demonstrate using the high-quality experimental data that turbulent wall jet flows consist of two self-similar layers: a top layer and a wall layer, separated by a mixing layer where the velocity is close to maximum. The top and wall layers are significantly different from each other, and both exhibit incomplete similarity, i.e., a strong influence of the width of the slot that had previously been neglected.

  17. Heavy flavour physics from top to bottom

    SciTech Connect

    Paulini, M.; CDF and D0 Collaboration

    1998-02-01

    We review the status of heavy flavour physics at the Fermilab Tevatron collider by summarizing recent top quark and B physics results from CDF and D0. In particular we discuss the measurement of the top quark mass and top production cross section as well as B meson lifetimes and time dependent B{anti B} mixing results. An outlook of perspectives for top and B physics in Run II starting in 1999 is also given.

  18. Cloud-top parameters - A hail indicator

    NASA Technical Reports Server (NTRS)

    Pearl, E. W.; Shenk, W. E.; Skillman, W.

    1975-01-01

    Airborne photographic observations of four hail-producing storms are discussed. With the exception of one storm producing a tornadic event, the overshooting tops were nearly steady-state. The tops were consistently high and wide, reaching maximum heights within about 5 minutes of the initiation of hail. Measured updraft velocities in the turrets composing the overshooting top were 25 m/sec. The dimensions of the overshooting tops were sufficiently large to permit satellite observation.

  19. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-07-01

    This eighteenth quarterly technical progress report of the MHD Integrated Topping cycle Project presents the accomplishments during the period November 1, 1991 to January 31, 1992. The precombustor is fully assembled. Manufacturing of all slagging stage components has been completed. All cooling panels were welded in place and the panel/shell gap was filled with RTV. Final combustor assembly is in progress. The low pressure cooling subsystem (LPCS) was delivered to the CDIF. Second stage brazing issues were resolved. The construction of the two anode power cabinets was completed.

  20. Table-top job analysis

    SciTech Connect

    Not Available

    1994-12-01

    The purpose of this Handbook is to establish general training program guidelines for training personnel in developing training for operation, maintenance, and technical support personnel at Department of Energy (DOE) nuclear facilities. TTJA is not the only method of job analysis; however, when conducted properly TTJA can be cost effective, efficient, and self-validating, and represents an effective method of defining job requirements. The table-top job analysis is suggested in the DOE Training Accreditation Program manuals as an acceptable alternative to traditional methods of analyzing job requirements. DOE 5480-20A strongly endorses and recommends it as the preferred method for analyzing jobs for positions addressed by the Order.

  1. HUBBLE'S TOP TEN GRAVITATIONAL LENSES

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The NASA Hubble Space Telescope serendipitous survey of the sky has uncovered exotic patterns, rings, arcs and crosses that are all optical mirages produced by a gravitational lens, nature's equivalent of having giant magnifying glass in space. Shown are the top 10 lens candidates uncovered in the deepest 100 Hubble fields. Hubble's sensitivity and high resolution allow it to see faint and distant lenses that cannot be detected with ground-based telescopes whose images are blurred by Earth's atmosphere. [Top Left] - HST 01248+0351 is a lensed pair on either side of the edge-on disk lensing galaxy. [Top Center] - HST 01247+0352 is another pair of bluer lensed source images around the red spherical elliptical lensing galaxy. Two much fainter images can be seen near the detection limit which might make this a quadruple system. [Top Right] - HST 15433+5352 is a very good lens candidate with a bluer lensed source in the form of an extended arc about the redder elliptical lensing galaxy. [Middle Far Left] - HST 16302+8230 could be an 'Einstein ring' and the most intriguing lens candidate. It has been nicknamed the 'the London Underground' since it resembles that logo. [Middle Near Left] - HST 14176+5226 is the first, and brightest lens system discovered in 1995 with the Hubble telescope. This lens candidate has now been confirmed spectroscopically using large ground-based telescopes. The elliptical lensing galaxy is located 7 billion light-years away, and the lensed quasar is about 11 billion light-years distant. [Middle Near Right] - HST 12531-2914 is the second quadruple lens candidate discovered with Hubble. It is similar to the first, but appears smaller and fainter. [Middle Far Right] - HST 14164+5215 is a pair of bluish lensed images symmetrically placed around a brighter, redder galaxy. [Bottom Left] - HST 16309+8230 is an edge-on disk-like galaxy (blue arc) which has been significantly distorted by the redder lensing elliptical galaxy. [Bottom Center] - HST 12368

  2. Top quark physics expectations at the LHC

    SciTech Connect

    ATLAS Collaboration; CMS Collaboration; Gaponenko, Andrei

    2008-09-30

    The top quark will be produced copiously at the LHC. This will make possible detailed physics studies, and also the use of top quark decays for detector calibration. This talk reviews plans and prospects for top physics activities in ATLAS and CMS experiments.

  3. Sliding Wear and Fretting Wear of DLC-Based, Functionally Graded Nanocomposite Coatings

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Pohlchuck, B.; Street, Kenneth W.; Zabinski, J. S.; Sanders, J. H.; Voevodin, A. a.; Wu, R. L. C.

    1999-01-01

    Improving the tribological functionality of diamondlike carbon (DLC) films--developing, good wear resistance, low friction, and high load-carrying capacity-was the aim of this investigation. Nanocomposite coatings consisting of an amorphous DLC (a-DLC) top layer and a functionally graded titanium-titanium carbon-diamondlike carbon (Ti-Ti(sub x) C(sub y)-DLC) underlayer were produced on AISI 440C stainless steel substrates by the hybrid technique of magnetron sputtering and pulsed-laser deposition. The resultant DLC films were characterized by Raman spectroscopy, scanning electron microscopy, and surface profilometry. Two types of wear experiment were conducted in this investioation: sliding friction experiments and fretting wear experiments. Unidirectional ball-on-disk sliding friction experiments were conducted to examine the wear behavior of an a-DLC/Ti-Ti(sub x) C(sub y)-DLC-coated AISI 440C stainless steel disk in sliding contact with a 6-mm-diameter AISI 440C stainless steel ball in ultrahigh vacuum, dry nitrogen, and humid air. Although the wear rates for both the coating and ball were low in all three environments, the humid air and dry nitrogen caused mild wear with burnishing, in the a-DLC top layer, and the ultrahigh vacuum caused relatively severe wear with brittle fracture in both the a-DLC top layer and the Ti-Ti(sub x) C(sub y)-DLC underlayer. For reference, amorphous hydrogenated carbon (H-DLC) films produced on a-DLC/Ti-Ti(sub x) C(sub y)-DLC nanocomposite coatings by using an ion beam were also examined in the same manner. The H-DLC films markedly reduced friction even in ultrahigh vacuum without sacrificing wear resistance. The H-DLC films behaved much like the a-DLC/Ti-Ti(sub x) C(sub y)-DLC nanocomposite coating in dry nitrogen and humid air, presenting low friction and low wear. Fretting wear experiments were conducted in humid air (approximately 50% relative humidity) at a frequency of 80 Hz and an amplitude of 75 micron on an a-DLC

  4. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-01-01

    The overall objective of the project is to design and construct prototypical hardware for an integrated MHD topping cycle, and conduct long duration proof-of-concept tests of integrated system at the US DOE Component Development and Integration Facility in Butte, Montana. The results of the long duration tests will augment the existing engineering design data base on MHD power train reliability, availability, maintainability, and performance, and will serve as a basis for scaling up the topping cycle design to the next level of development, an early commercial scale power plant retrofit. The components of the MHD power train to be designed, fabricated, and tested include: A slagging coal combustor with a rated capacity of 50 MW thermal input, capable of operation with an Eastern (Illinois {number sign}6) or Western (Montana Rosebud) coal, a segmented supersonic nozzle, a supersonic MHD channel capable of generating at least 1.5 MW of electrical power, a segmented supersonic diffuser section to interface the channel with existing facility quench and exhaust systems, a complete set of current control circuits for local diagonal current control along the channel, and a set of current consolidation circuits to interface the channel with the existing facility inverter.

  5. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-03-01

    The Magnetohydrodynamics (MHD) Integrated Topping Cycle (ITC) Project represents the culmination of the proof-of-concept (POC) development stage in the US Department of Energy (DOE) program to advance MHD technology to early commercial development stage utility power applications. The project is a joint effort, combining the skills of three topping cycle component developers: TRW, Avco/TDS, and Westinghouse. TRW, the prime contractor and system integrator, is responsible for the 50 thermal megawatt (50 MW{sub t}) slagging coal combustion subsystem. Avco/TDS is responsible for the MHD channel subsystem (nozzle, channel, diffuser, and power conditioning circuits), and Westinghouse is responsible for the current consolidation subsystem. The ITC Project will advance the state-of-the-art in MHD power systems with the design, construction, and integrated testing of 50 MW{sub t} power train components which are prototypical of the equipment that will be used in an early commercial scale MHD utility retrofit. Long duration testing of the integrated power train at the Component Development and Integration Facility (CDIF) in Butte, Montana will be performed, so that by the early 1990's, an engineering data base on the reliability, availability, maintainability and performance of the system will be available to allow scaleup of the prototypical designs to the next development level. This Sixteenth Quarterly Technical Progress Report covers the period May 1, 1991 to July 31, 1991.

  6. Top quark physics at CDF

    SciTech Connect

    Caner, A.; CDF Collaboration

    1996-08-01

    We present preliminary results on top quark physics recently obtained by the CDF collaboration. The data sample consists of 110 {ital pb}{sup -1} of {ital p{anti p}} collisions at {radical}{ital s} = 1.8 TeV, collected with the Collider Detector at Fermilab during the period 1992 - 1995. We report on the {ital t{anti t}} production cross section and on the top quark mass. The measurements are made in three topologies, corresponding to the decay modes of the {ital Wb} pairs in the final state: lepton + multi-jets, dilepton and all hadronic final state. The analysis performed on the single lepton sample yields the most accurate measurements, due to the good acceptance and the favorable signal to noise ratio obtained after applying some b-tagging techniques. In this channel we measure: {sigma}{sub {ital t{anti t}}} = 6.8{sup +2.3}{sub -1.8} pb M{sub {ital t}} = 175.6 {+-} 5.7 ({ital stat}) {+-} 7.1 ({ital syst.}) {ital GeV/c{sup 2}} Combining the cross sections measured with the lepton + multi-jet and dilepton data we obtain: {sigma}{sub {ital t{anti t}}} = 7.5{sup +1.9}{sub -1.6} {ital pb} A preliminary investigation of the production mechanism of the {ital t{anti t}} system is shown and compared to Standard Model expectations.

  7. CP Violation in Single Top Quark Production

    SciTech Connect

    Geng, Weigang

    2012-01-01

    We present a search for CP violation in single top quark production with the DØ experiment at the Tevatron proton-antiproton collider. CP violation in the top electroweak interaction results in different single top quark production cross sections for top and antitop quarks. We perform the search in the single top quark final state using 5.4 fb-1 of data, in the s-channel, t-channel, and for both combined. At this time, we do not see an observable CP asymmetry.

  8. Top Quark Studies at D0

    SciTech Connect

    Peters, Reinhild Yvonne

    2014-11-26

    Years after its discovery in 1995 by CDF and D0, the top quark still undergoes intense investigations at the Tevatron. Using up to the full Run II data sample, new measurements of top quark production and properties by the D0 Collaboration are presented. In particular, the first observation of single top quark s-channel production, the measurement of differential tbar t distributions, forward-backward tbar t asymmetry, a new measurement of the top quark mass, and a measurement of the top quark charge are discussed.

  9. Measurements of top quark properties at CDF

    SciTech Connect

    Kraan, Aafke C.; /Pennsylvania U.

    2006-11-01

    The top quark with its mass of about 172 GeV/c{sup 2} is the most massive fundamental particle observed by experiment. In this talk they highlight the most recent measurements of several top quark properties performed with the CDF detector based on data samples corresponding to integrated luminosities up to 1 fb{sup -1}. These results include a search for top quark pair production via new massive resonances, measurements of the helicity of the W boson from top-quark decay, and a direct limit on the lifetime of the top quark.

  10. Fly ash in landfill top covers - a review.

    PubMed

    Brännvall, E; Kumpiene, J

    2016-01-01

    Increase of energy recovery from municipal solid waste by incineration results in the increased amounts of incineration residues, such as fly ash, that have to be taken care of. Material properties should define whether fly ash is a waste or a viable resource to be used for various applications. Here, two areas of potential fly ash application are reviewed: the use of fly ash in a landfill top cover either as a liner material or as a soil amendment in vegetation layer. Fly ashes from incineration of three types of fuel are considered: refuse derived fuel (RDF), municipal solid waste incineration (MSWI) and biofuel. Based on the observations, RDF and MSWI fly ash is considered as suitable materials to be used in a landfill top cover liner. Whereas MSWI and biofuel fly ashes based on element availability for plant studies, could be considered suitable for the vegetation layer of the top cover. Responsible application of MSWI ashes is, however, warranted in order to avoid element accumulation in soil and elevation of background values over time.

  11. Intra-layer synchronization in multiplex networks

    NASA Astrophysics Data System (ADS)

    Gambuzza, L. V.; Frasca, M.; Gómez-Gardeñes, J.

    2015-04-01

    We study synchronization of N oscillators indirectly coupled through a medium which is inhomogeneous and has its own dynamics. The system is formalized in terms of a multilayer network, where the top layer is made of disconnected oscillators and the bottom one, modeling the medium, consists of oscillators coupled according to a given topology. The different dynamics of the medium and the top layer is accounted for by including a frequency mismatch between them. We show a novel regime of synchronization as intra-layer coherence does not necessarily require inter-layer coherence. This regime appears under mild conditions on the bottom layer: arbitrary topologies may be considered, provided that they support synchronization of the oscillators of the medium. The existence of a density-dependent threshold as in quorum-sensing phenomena is also demonstrated.

  12. Highly efficient white top-emitting organic light-emitting diodes comprising laminated microlens films.

    PubMed

    Thomschke, Michael; Reineke, Sebastian; Lüssem, Björn; Leo, Karl

    2012-01-11

    White top-emitting organic light-emitting diodes (OLEDs) attract much attention, as they are optically independent from the substrate used. While monochrome top-emitting OLEDs can be designed easily to have high-emission efficiency, white light emission faces obstacles. The commonly used thin metal layers as top electrodes turn the device into a microresonator having detrimental narrow and angular dependent emission characteristics. Here we report on a novel concept to improve the color quality and efficiency of white top-emitting OLEDs. We laminate a refractive index-matched microlens film on the top-emitting device. The microlens film acts both as outcoupling-enhancing film and an integrating element, mixing the optical modes to a broadband spectrum.

  13. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-07-01

    This seventeenth quarterly technical progress report of the MHD Integrated Topping Cycle Project presents the accomplishments during the period August 1, 1991 to October 31, 1991. Manufacturing of the prototypical combustor pressure shell has been completed including leak, proof, and assembly fit checking. Manufacturing of forty-five cooling panels was also completed including leak, proof, and flow testing. All precombustor internal components (combustion can baffle and swirl box) were received and checked, and integration of the components was initiated. A decision was made regarding the primary and backup designs for the 1A4 channel. The assembly of the channel related prototypical hardware continued. The cathode wall electrical wiring is now complete. The mechanical design of the diffuser has been completed.

  14. The design of Top-Hat morphological filter and application to infrared target detection

    NASA Astrophysics Data System (ADS)

    Zeng, Ming; Li, Jianxun; Peng, Zhang

    2006-04-01

    Automatic detection and track for infrared target is of great significance in modern world. In this paper, two novel methods which can develop optimizing Top-Hat morphological filtering parameters are presented for spot target detection. One is based on neural network. Its structuring element is a two-layer feed-forward network which is trained by a mass of sample nets. It regards Top-Hat operation as a whole and one layer, and defines the node of the output layer as the maximum gray-scale image vector after Top-Hat operation. The other is based on genetic algorithm. It adopts the interval discretization code and new primary and secondary mood crossover and mutation. Experimental results show that the identified probability of images (SNR is about 2) can reach more than 98% by this method.

  15. The rise and fall of spinning tops

    NASA Astrophysics Data System (ADS)

    Cross, Rod

    2013-04-01

    The motion of four different spinning tops was filmed with a high-speed video camera. Unlike pointed tops, tops with a rounded peg precess initially about a vertical axis that lies well outside the top, and then spiral inward until the precession axis passes through a point close to the center-of-mass. The center-of-mass of a top with a rounded peg can rise as a result of rolling rather than sliding friction, contrary to the explanation normally given for the rise of spinning tops. A tippe top was also filmed and was observed to jump vertically off a horizontal surface several times while the center-of-mass was rising, contrary to the usual assumption that the normal reaction force on a tippe top remains approximately equal to its weight. It was found that the center-of-mass of a tippe top rises as a result of rolling friction at low spin frequencies and as a result of sliding friction at high spin frequencies. It was also found that, at low spin frequencies, a tippe top can precess at two different frequencies simultaneously.

  16. Nonmixing layers

    NASA Astrophysics Data System (ADS)

    Gaillard, Pierre; Giovangigli, Vincent; Matuszewski, Lionel

    2016-12-01

    We investigate the impact of nonideal diffusion on the structure of supercritical cryogenic binary mixing layers. This situation is typical of liquid fuel injection in high-pressure rocket engines. Nonideal diffusion has a dramatic impact in the neighborhood of chemical thermodynamic stability limits where the components become quasi-immiscible and ultimately form a nonmixing layer. Numerical simulations are performed for mixing layers of H2 and N2 at a pressure of 100 atm and temperature around 120-150 K near chemical thermodynamic stability limits.

  17. Top quark mass: past, present and future

    SciTech Connect

    Gutierrez, Gaston; /Fermilab

    2007-07-01

    The top quark is the most massive elementary particle discovered thus far. Its large mass may help explain the mechanism by which fundamental particles gain mass - the Standard Model's greatest standing mystery. Today the top quark mass, together with the W boson mass, plays an important role in constraining the Higgs boson mass. The current status of the top quark mass measurement and a brief outline of the expectation at the Large Hadron Collider and the International Linear Collider will be covered.

  18. TOP500 Supercomputers for June 2005

    SciTech Connect

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2005-06-22

    25th Edition of TOP500 List of World's Fastest Supercomputers Released: DOE/L LNL BlueGene/L and IBM gain Top Positions MANNHEIM, Germany; KNOXVILLE, Tenn.; BERKELEY, Calif. In what has become a closely watched event in the world of high-performance computing, the 25th edition of the TOP500 list of the world's fastest supercomputers was released today (June 22, 2005) at the 20th International Supercomputing Conference (ISC2005) in Heidelberg Germany.

  19. TOP500 Supercomputers for November 2004

    SciTech Connect

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2004-11-08

    24th Edition of TOP500 List of World's Fastest Supercomputers Released: DOE/IBM BlueGene/L and NASA/SGI's Columbia gain Top Positions MANNHEIM, Germany; KNOXVILLE, Tenn.; BERKELEY, Calif. In what has become a closely watched event in the world of high-performance computing, the 24th edition of the TOP500 list of the worlds fastest supercomputers was released today (November 8, 2004) at the SC2004 Conference in Pittsburgh, Pa.

  20. Top quark mass measurements at CDF

    SciTech Connect

    Maki, Tuula; /Helsinki U. /Helsinki Inst. of Phys.

    2007-10-01

    The top quark mass is interesting both as a fundamental parameter of the standard model as well as an important input to precision electroweak tests. The CDF Collaboration has measured the top quark mass with high precision in all decay channels with complementary methods. A combination of the results from CDF gives a top quark mass of 170.5{+-}1.3(stat.){+-}1.8(syst.) GeV/c{sup 2}.

  1. TOP500 Supercomputers for June 2004

    SciTech Connect

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2004-06-23

    23rd Edition of TOP500 List of World's Fastest Supercomputers Released: Japan's Earth Simulator Enters Third Year in Top Position MANNHEIM, Germany; KNOXVILLE, Tenn.;&BERKELEY, Calif. In what has become a closely watched event in the world of high-performance computing, the 23rd edition of the TOP500 list of the world's fastest supercomputers was released today (June 23, 2004) at the International Supercomputer Conference in Heidelberg, Germany.

  2. Top quark physics at the Tevatron

    SciTech Connect

    D. Gerdes

    2004-01-28

    Precision studies of the top quark are a prime goal of the Run II physics program at the Fermilab Tevatron. Since the start of Run II in early 2002, the CDF and D0 experiments have analyzed approximately 100 pb{sup -1} of data and have re-established the top quark signal. In this article the author summarizes recent measurements of the top production cross section and mass.

  3. High voltage switches having one or more floating conductor layers

    SciTech Connect

    Werne, Roger W.; Sampayan, Stephen; Harris, John Richardson

    2015-11-24

    This patent document discloses high voltage switches that include one or more electrically floating conductor layers that are isolated from one another in the dielectric medium between the top and bottom switch electrodes. The presence of the one or more electrically floating conductor layers between the top and bottom switch electrodes allow the dielectric medium between the top and bottom switch electrodes to exhibit a higher breakdown voltage than the breakdown voltage when the one or more electrically floating conductor layers are not present between the top and bottom switch electrodes. This increased breakdown voltage in the presence of one or more electrically floating conductor layers in a dielectric medium enables the switch to supply a higher voltage for various high voltage circuits and electric systems.

  4. Boat Deck, Cabin Deck, Bridge Deck, Flat House Top, Stage ...

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

    Boat Deck, Cabin Deck, Bridge Deck, Flat House Top, Stage Top, Mast House Top, Upper Deck, Flat House Tops, Forecastle Deck, Main Deck - American Racer, Suisun Bay Reserve Fleet, Benicia, Solano County, CA

  5. Top Quark Mass Measurements at the Tevatron

    SciTech Connect

    Peters, Reinhild Yvonne

    2014-01-01

    Since the discovery of the top quark in 1995 by the CDF and D0 collaborations at the Fermilab Tevatron proton antiproton collider, precise measurements of its mass are ongoing. Using data recorded by the D0 and CDF experiment, corresponding to up to the full Tevatron data sample, top quark mass measurements performed in different final states using various extraction techniques are presented in this article. The recent Tevatron top quark mass combination yields m_t=173.20 +-0.87 GeV. Furthermore, measurements of the top antitop quark mass difference from the Tevatron are discussed.

  6. Top Quark Production Asymmetries AFBt and AFBl

    DOE PAGES

    Berger, Edmond L.; Cao, Qing-Hong; Chen, Chuan-Ren; ...

    2012-02-14

    A large forward-backward asymmetry is seen in both the top quark rapidity distribution AFBt and in the rapidity distribution of charged leptons AFBl from top quarks produced at the Tevatron. We study the kinematic and dynamic aspects of the relationship of the two observables arising from the spin correlation between the charged lepton and the top quark with different polarization states. We emphasize the value of both measurements, and we conclude that a new physics model which produces more right-handed than left-handed top quarks is favored by the present data.

  7. Spallanzani Layers

    NASA Technical Reports Server (NTRS)

    2006-01-01

    31 March 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a layered, light-toned mesa among other layered materials exposed in a mound that covers much of the floor of Spallanzani Crater.

    Location near: 58.3oS, 273.9oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  8. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-02-01

    This fourteenth quarterly technical progress report of the MHD Integrated Topping Cycle Project presents the accomplishments during the period November 1, 1990 to January 31, 1991. Testing of the High Pressure Cooling Subsystem electrical isolator was completed. The PEEK material successfully passed the high temperature, high pressure duration tests (50 hours). The Combustion Subsystem drawings were CADAM released. The procurement process is in progress. An equipment specification and RFP were prepared for the new Low Pressure Cooling System (LPCS) and released for quotation. Work has been conducted on confirmation tests leading to final gas-side designs and studies to assist in channel fabrication.The final cathode gas-side design and the proposed gas-side designs of the anode and sidewall are presented. Anode confirmation tests and related analyses of anode wear mechanisms used in the selection of the proposed anode design are presented. Sidewall confirmation tests, which were used to select the proposed gas-side design, were conducted. The design for the full scale CDIF system was completed. A test program was initiated to investigate the practicality of using Avco current controls for current consolidation in the power takeoff (PTO) regions and to determine the cause of past current consolidation failures. Another important activity was the installation of 1A4-style coupons in the 1A1 channel. A description of the coupons and their location with 1A1 channel is presented herein.

  9. Top-of-Rail lubricant

    SciTech Connect

    Alzoubi, M. F.; Fenske, G. R.; Erck, R. A.; Boparai, A. S.

    2000-07-14

    Analysis of the volatile and semivolatile fractions collected after use of the TOR lubricant indicated that other than contaminants in the collection laboratory, no compounds on the EPA's Target Compound Lists (Tables 2 and 5) were detected in these fractions. The data of these qualitative analyses, given in the various tables in the text, indicate only the relative amounts of the tentatively identified compounds. The authors recommend that quantitative analysis be performed on the volatile and semivolatile fractions to allow confirmation of the tentatively identified compounds and to obtain absolute amounts of the detected compounds. Additionally, the semivolatile fraction should be analyzed by liquid chromatography/mass spectrometry to identify compounds that are not chromatographable under the temperature program used for determination of semivolatile compounds. Introducing the top-of-rail (TOR) lubricant into the wheel/rail interface results in a reduction of almost 60% of lateral friction force over the forces encountered under dry conditions. This reveals good potential for energy savings, as well as wear reduction, for railroad companies. In TOR lubrication, an increase in the angle of attack and axle load results in increased lateral friction and rate of lubricant consumption. The most efficient TOR lubricant quantity to be used in the wheel/rail interface must be calculated precisely according to the number of cars, axle loads, train speed, and angle of attack.

  10. Preliminary results of fluid dynamic model calculation of convective motion induced by solar heating at the Venus cloud top level.

    NASA Astrophysics Data System (ADS)

    Lee, Yeon Joo; Imamura, Takeshi; Maejima, Yasumitsu; Sugiyama, Ko-ichiro

    The thick cloud layer of Venus reflects solar radiation effectively, resulting in a Bond albedo of 76% (Moroz et al., 1985). Most of the incoming solar flux is absorbed in the upper cloud layer at 60-70 km altitude. An unknown UV absorber is a major sink of the solar energy at the cloud top level. It produces about 40-60% of the total solar heating near the cloud tops, depending on its vertical structure (Crisp et al., 1986; Lee et al., in preparation). UV images of Venus show a clear difference in morphology between laminar flow shaped clouds on the morning side and convective-like cells on the afternoon side of the planet in the equatorial region (Titov et al., 2012). This difference is probably related to strong solar heating at the cloud tops at the sub-solar point, rather than the influence from deeper level convection in the low and middle cloud layers (Imamura et al., 2014). Also, small difference in cloud top structures may trigger horizontal convection at this altitude, because various cloud top structures can significantly alter the solar heating and thermal cooling rates at the cloud tops (Lee et al., in preparation). Performing radiative forcing calculations for various cloud top structures using a radiative transfer model (SHDOM), we investigate the effect of solar heating at the cloud tops on atmospheric dynamics. We use CReSS (Cloud Resolving Storm Simulator), and consider the altitude range from 35 km to 90 km, covering a full cloud deck.

  11. An insolation activated dust layer on Mars

    NASA Astrophysics Data System (ADS)

    de Beule, Caroline; Wurm, Gerhard; Kelling, Thorben; Koester, Marc; Kocifaj, Miroslav

    2015-11-01

    The illuminated dusty surface of Mars acts like a gas pump. It is driven by thermal creep at low pressure within the soil. In the top soil layer this gas flow has to be sustained by a pressure gradient. This is equivalent to a lifting force on the dust grains. The top layer is therefore under tension which reduces the threshold wind speed for saltation. We carried out laboratory experiments to quantify the thickness of this activated layer. We use basalt with an average particle size of 67 μm. We find a depth of the active layer of 100-200 μm. Scaled to Mars the activation will reduce threshold wind speeds for saltation by about 10%.

  12. Measuring top-quark polarization in top-pair + missing-energy events.

    PubMed

    Berger, Edmond L; Cao, Qing-Hong; Yu, Jiang-Hao; Zhang, Hao

    2012-10-12

    The polarization of a top quark can be sensitive to new physics beyond the standard model. Since the charged lepton from top-quark decay is maximally correlated with the top-quark spin, it is common to measure the polarization from the distribution in the angle between the charged lepton and the top-quark directions. We propose a novel method based on the charged lepton energy fraction and illustrate the method with a detailed simulation of top-quark pairs produced in supersymmetric top squark pair production. We show that the lepton energy ratio distribution that we define is very sensitive to the top-quark polarization but insensitive to the precise measurement of the top-quark energy.

  13. Review of Top Quark Physics Results

    SciTech Connect

    Kehoe, R.; Narain, M.; Kumar, A.

    2007-12-01

    As the heaviest known fundamental particle, the top quark has taken a central role in the study of fundamental interactions. Production of top quarks in pairs provides an important probe of strong interactions. The top quark mass is a key fundamental parameter which places a valuable constraint on the Higgs boson mass and electroweak symmetry breaking. Observations of the relative rates and kinematics of top quark final states constrain potential new physics. In many cases, the tests available with study of the top quark are both critical and unique. Large increases in data samples from the Fermilab Tevatron have been coupled with major improvements in experimental techniques to produce many new precision measurements of the top quark. The first direct evidence for electroweak production of top quarks has been obtained, with a resulting direct determination of V{sub tb}. Several of the properties of the top quark have been measured. Progress has also been made in obtaining improved limits on potential anomalous production and decay mechanisms. This review presents an overview of recent theoretical and experimental developments in this field. We also provide a brief discussion of the implications for further efforts.

  14. The Sakai Spinner: A Paperclip Top

    ERIC Educational Resources Information Center

    Corrao, Christian T.

    2014-01-01

    A challenge: Can you create a stable top from a single paper clip? Several interesting solutions to this problem were provided by Takao Sakai from Japan, the requirement of each being that the center of gravity be located on the vertical y-axis at the center of the top. In the simplest configuration, we see that there exists a single angle ?…

  15. Top-Ten IT Issues, 2008

    ERIC Educational Resources Information Center

    Allison, Debra H.; DeBlois, Peter B.

    2008-01-01

    EDUCAUSE presents the top-ten IT-related issues in terms of strategic importance to the higher education institution, as revealed by the ninth annual EDUCAUSE Current Issues Survey. This year, "Security" moves back to the top of the list. (Contains 20 notes.)

  16. 49 CFR 236.779 - Plate, top.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Plate, top. 236.779 Section 236.779 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top....

  17. 49 CFR 236.779 - Plate, top.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Plate, top. 236.779 Section 236.779 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top....

  18. Race to Top Draws out New Suitors

    ERIC Educational Resources Information Center

    McNeil, Michele

    2012-01-01

    The list of 61 finalists for the latest Race to the Top competition shows that the U.S. Department of Education was successful in enticing high-scoring applications from districts in rural America and in states that had not shared in the Race to the Top bounty before. But whether the ultimate winners, which will be announced this month, will be…

  19. Top 12 Web Resources for 2012

    ERIC Educational Resources Information Center

    Gonzales, Lisa; Vodicka, Devin

    2012-01-01

    In this article, the authors describe some of the top websites recommended by colleagues for the Association of California School Administrators. The Top 12 for 2012 are: (1) Facebook (facebook.com); (2) Twitter (twitter.com); (3) Tungle (tungle.me); (4) FCMAT (fcmat.org); (5) YouSendIt (yousendit.com); (6) Slideshare (slideshare.net); (7) QR…

  20. Controlling Severe Curly Top in Sugarbeets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Controlling curly top in sugarbeet has been industry priority in the western United States since the 1920s. Curly top is a virus disease that is vectored by the beet leafhopper. If the beet leafhopper moves into commercial fields early in the season, virus is more likely to be transmitted to sugar...

  1. Pinch Experiments in a Table Top Generator

    SciTech Connect

    Pavez, Cristian; Moreno, Jose; Soto, Leopoldo; Tarifeno, Ariel

    2009-01-21

    The design and construction of a table top multipurpose capacitor bank of hundred of Joules and hundred of kiloAmperes conceived to be used in small scale Z-pinch experiments is reported. A recent result on a Z-pinch gas embedded discharge using hollow conical electrodes done in a similar table top generator is also presented.

  2. Search for top quark at Fermilab Collider

    SciTech Connect

    Sliwa, K.; The CDF Collaboration

    1991-10-01

    The status of a search for the top quark with Collider Detector at Fermilab (CDF), based on a data sample recorded during the 1988--1989 run is presented. The plans for the next Fermilab Collider run in 1992--1993 and the prospects of discovering the top quark are discussed. 19 refs., 4 figs., 2 tabs.

  3. World average top-quark mass

    SciTech Connect

    Glenzinski, D.; /Fermilab

    2008-01-01

    This paper summarizes a talk given at the Top2008 Workshop at La Biodola, Isola d Elba, Italy. The status of the world average top-quark mass is discussed. Some comments about the challanges facing the experiments in order to further improve the precision are offered.

  4. Physics of the top quark at CDF

    SciTech Connect

    Vejcik, S.; CDF Collaboration

    1997-07-01

    Measurements of Top quark properties with the CDF detector are reported. The production cross section and mass provide a consistent picture of the Top quark as described by the Standard Model. Initial studies of other properties such as estimates of branching ratios are also reported.

  5. Tools for top physics at D0

    SciTech Connect

    Harel, Amnon

    2008-07-01

    Top quark measurements rely on the jet energy calibration and often on b-quark identification. We discuss these and other tools and how they apply to top quark analyses at D0. In particular some of the nuances that result from D0's data driven approach to these issues are presented.

  6. Top Quark Pair Production at the Tevatron

    SciTech Connect

    Nielsen, Jason

    2005-05-17

    The measurement of the top quark pair production crosssection inproton-antiproton collisions at 1.96 TeV is a test ofquantumchromodynamics and could potentially be sensitive to newphysics beyondthe standard model. I report on the latest t-tbarcross section resultsfrom the CDF and DZero experiments in various finalstate topologies whicharise from decays of top quark pairs.

  7. Surface layering effect of diluted Intralipid

    NASA Astrophysics Data System (ADS)

    Foschum, F.; Bodenschatz, N.; Krauter, P.; Nothelfer, S.; Liemert, A.; Simon, E.; Kröner, S.; Kienle, A.

    2015-07-01

    In this study the formation of a surface layer on top of an Intralipid dilution was studied. By use of spatial frequency reflectance and spatially resolved reflectance the surface layer could be characterized. The influence on the determination of the optical properties assuming a semi-infinite medium in the theory was investigated. By use of an angularly resolved reflectance device the formation even on a horizontally orientated glass slide could be shown.

  8. TOP500 Supercomputers for June 2002

    SciTech Connect

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2002-06-20

    19th Edition of TOP500 List of World's Fastest Supercomputers Released MANNHEIM, Germany; KNOXVILLE, Tenn.;&BERKELEY, Calif. In what has become a much-anticipated event in the world of high-performance computing, the 19th edition of the TOP500 list of the worlds fastest supercomputers was released today (June 20, 2002). The recently installed Earth Simulator supercomputer at the Earth Simulator Center in Yokohama, Japan, is as expected the clear new number 1. Its performance of 35.86 Tflop/s (trillions of calculations per second) running the Linpack benchmark is almost five times higher than the performance of the now No.2 IBM ASCI White system at Lawrence Livermore National Laboratory (7.2 Tflop/s). This powerful leap frogging to the top by a system so much faster than the previous top system is unparalleled in the history of the TOP500.

  9. Thermionic topping of electric power plants

    NASA Technical Reports Server (NTRS)

    Britt, E. J.; Fitzpatrick, G. O.; Rasor, N. S.

    1975-01-01

    The most likely use of thermionic conversion is in the form of a topping cycle combined with a steam-turbogenerator plant. A specific reference system is chosen in which the thermionic topping cycle occurs in thermionic heat exchangers referred to as large, modular thermionic units to which heat is transferred from a separate heat source and which reject their heat to a conventional steam turboelectric system. Results of analysis show that the performance and cost criteria for practical thermionic topping of large electric power plants are well within the reach of demonstrated and foreseeable converter capabilities. Thermionic topping has many significant advantages over unconventional cycles proposed for topping applications, including level of demonstrated and projected performance and lifetime, development time, and design simplicity.

  10. Protein Identification Using Top-Down

    SciTech Connect

    Liu, Xiaowen; Sirotkin, Yakov; Shen, Yufeng; Anderson, Gordon A.; Tsai, Yi-Hsuan S.; Ting, Ying S.; Goodlett, David R.; Smith, Richard D.; Bafna, Vineet; Pevzner, Pavel A.

    2012-06-01

    In the last two years, due to advances in protein separation and mass spectrometry, top-down mass spectrometry moved from analyzing single proteins to analyzing complex samples and identifying hundreds and even thousands of proteins. However, computational tools for database search of top-down spectra against protein databases are still in infancy. We describe MS-Align+, a fast algorithm for top-down protein identification based on spectral alignment that enables searches for unexpected post-translational modifications (PTMs). We also propose a method for evaluating statistical significance of top-down protein identifications and further benchmark MS-Align+ along with PIITA, ProSightPTM and SEQUEST, which were previously used for top-down MS/MS database searches. We demonstrate that MS-Align+ and PIITA significantly increase the number of identified proteins as compared to ProSightPTM and SEQUEST.

  11. Enhanced solar energy harvesting using top n-contact GaAs solar cell

    NASA Astrophysics Data System (ADS)

    Das, N. C.

    2015-05-01

    We fabricated single-junction solar cell on molecular beam epitaxially grown p-n junction on n-type gallium arsenide (GaAs) substrate. We used a germanium (Ge)/gold (Au)/nickel (Ni)/Au metal contact from the top side on a highly doped n+ epitaxial layer as well as the bottom side on an n-type GaAs substrate. We observed 10-15% increase in solar cell power when the top contact is used for the n+ GaAs epi layer compared to the bottom side n-type GaAs substrate. Solar cell fill factor, sheet, and shunt resistances are same for both the top and bottom contact type devices. We also observed higher external quantum efficiency (EQE) for top contact devices compared to bottom contact devices. We conclude that to achieve higher power, it is advantageous to use an n-type contact from a highly doped top n+ epitaxial layer rather than a bottom n-type GaAs substrate.

  12. Measurements and searches with top quarks

    SciTech Connect

    Peters, Reinhild Yvonne

    2008-08-01

    In 1995 the last missing member of the known families of quarks, the top quark, was discovered by the CDF and D0 experiments at the Tevatron, a proton-antiproton collider at Fermilab near Chicago. Until today, the Tevatron is the only place where top quarks can be produced. The determination of top quark production and properties is crucial to understand the Standard Model of particle physics and beyond. The most striking property of the top quark is its mass--of the order of the mass of a gold atom and close to the electroweak scale--making the top quark not only interesting in itself but also as a window to new physics. Due to the high mass, much higher than of any other known fermion, it is expected that the top quark plays an important role in electroweak symmetry breaking, which is the most prominent candidate to explain the mass of particles. In the Standard Model, electroweak symmetry breaking is induced by one Higgs field, producing one additional physical particle, the Higgs boson. Although various searches have been performed, for example at the Large Electron Positron Collider (LEP), no evidence for the Higgs boson could yet be found in any experiment. At the Tevatron, multiple searches for the last missing particle of the Standard Model are ongoing with ever higher statistics and improved analysis techniques. The exclusion or verification of the Higgs boson can only be achieved by combining many techniques and many final states and production mechanisms. As part of this thesis, the search for Higgs bosons produced in association with a top quark pair (t$\\bar{t}$H) has been performed. This channel is especially interesting for the understanding of the coupling between Higgs and the top quark. Even though the Standard Model Higgs boson is an attractive candidate, there is no reason to believe that the electroweak symmetry breaking is induced by only one Higgs field. In many models more than one Higgs boson are expected to exist, opening even more

  13. Discovery of single top quark production

    SciTech Connect

    Gillberg, Dag

    2009-04-01

    The top quark is by far the heaviest known fundamental particle with a mass nearing that of a gold atom. Because of this strikingly high mass, the top quark has several unique properties and might play an important role in electroweak symmetry breaking - the mechanism that gives all elementary particles mass. Creating top quarks requires access to very high energy collisions, and at present only the Tevatron collider at Fermilab is capable of reaching these energies. Until now, top quarks have only been observed produced in pairs via the strong interaction. At hadron colliders, it should also be possible to produce single top quarks via the electroweak interaction. Studies of single top quark production provide opportunities to measure the top quark spin, how top quarks mix with other quarks, and to look for new physics beyond the standard model. Because of these interesting properties, scientists have been looking for single top quarks for more than 15 years. This thesis presents the first discovery of single top quark production. An analysis is performed using 2.3 fb-1 of data recorded by the D0 detector at the Fermilab Tevatron Collider at centre-of-mass energy √s = 1.96 TeV. Boosted decision trees are used to isolate the single top signal from background, and the single top cross section is measured to be σ(p$\\bar{p}$ → tb + X, tqb + X) = 3.74-0.74+0.95 pb. Using the same analysis, a measurement of the amplitude of the CKM matrix element Vtb, governing how top and b quarks mix, is also performed. The measurement yields: |V{sub tb}|f1L| = 1.05 -0.12+0.13, where f1L is the left-handed Wtb coupling. The separation of signal from background is improved by combining the boosted decision trees with two other multivariate techniques. A new cross section measurement is performed, and the significance for the excess over the predicted background exceeds 5

  14. Enhanced light extraction in tunnel junction-enabled top emitting UV LEDs

    DOE PAGES

    Zhang, Yuewei; Allerman, Andrew A.; Krishnamoorthy, Sriram; ...

    2016-04-11

    The efficiency of ultra violet LEDs has been critically limited by the absorption losses in p-type and metal layers. In this work, surface roughening based light extraction structures are combined with tunneling based p-contacts to realize highly efficient top-side light extraction efficiency in UV LEDs. Surface roughening of the top n-type AlGaN contact layer is demonstrated using self-assembled Ni nano-clusters as etch mask. The top surface roughened LEDs were found to enhance external quantum efficiency by over 40% for UV LEDs with a peak emission wavelength of 326 nm. The method described here can enable highly efficient UV LEDs withoutmore » the need for complex manufacturing methods such as flip chip bonding.« less

  15. Enhanced light extraction in tunnel junction-enabled top emitting UV LEDs

    SciTech Connect

    Zhang, Yuewei; Allerman, Andrew A.; Krishnamoorthy, Sriram; Akyol, Fatih; Moseley, Michael W.; Armstrong, Andrew M.; Rajan, Siddharth

    2016-04-11

    The efficiency of ultra violet LEDs has been critically limited by the absorption losses in p-type and metal layers. In this work, surface roughening based light extraction structures are combined with tunneling based p-contacts to realize highly efficient top-side light extraction efficiency in UV LEDs. Surface roughening of the top n-type AlGaN contact layer is demonstrated using self-assembled Ni nano-clusters as etch mask. The top surface roughened LEDs were found to enhance external quantum efficiency by over 40% for UV LEDs with a peak emission wavelength of 326 nm. The method described here can enable highly efficient UV LEDs without the need for complex manufacturing methods such as flip chip bonding.

  16. Measurement of the top quark mass

    SciTech Connect

    Blusk, Steven R.

    1998-05-01

    The first evidence and subsequent discovery of the top quark was reported nearly 4 years ago. Since then, CDF and D0 have analyzed their full Run 1 data samples, and analysis techniques have been refined to make optimal use of the information. In this paper, we report on the most recent measurements of the top quark mass, performed by the CDF and D0 collaborations at the Fermilab Tevatron. The CDF collaboration has performed measurements of the top quark mass in three decay channels from which the top quark mass is measured to be 175.5 {+-} 6.9 GeV=c{sup 2}. The D0 collaboration combines measurements from two decay channels to obtain a top quark mass of 172.1 {+-} 7.1 GeV/c{sup 2}. Combining the measurements from the two experiments, assuming a 2 GeV GeV/c{sup 2} correlated systematic uncertainty, the measurement of the top quark mass at the Tevatron is 173.9 {+-} 5.2 GeV/c{sup 2}. This report presents the measurements of the top quark mass from each of the decay channels which contribute to this measurement.

  17. The Top Quark, QCD, And New Physics.

    DOE R&D Accomplishments Database

    Dawson, S.

    2002-06-01

    The role of the top quark in completing the Standard Model quark sector is reviewed, along with a discussion of production, decay, and theoretical restrictions on the top quark properties. Particular attention is paid to the top quark as a laboratory for perturbative QCD. As examples of the relevance of QCD corrections in the top quark sector, the calculation of e{sup+}e{sup -}+ t{bar t} at next-to-leading-order QCD using the phase space slicing algorithm and the implications of a precision measurement of the top quark mass are discussed in detail. The associated production of a t{bar t} pair and a Higgs boson in either e{sup+}e{sup -} or hadronic collisions is presented at next-to-leading-order QCD and its importance for a measurement of the top quark Yulrawa coupling emphasized. Implications of the heavy top quark mass for model builders are briefly examined, with the minimal supersymmetric Standard Model and topcolor discussed as specific examples.

  18. Screen printed silver top electrode for efficient inverted organic solar cells

    SciTech Connect

    Kim, Junwoo; Duraisamy, Navaneethan; Lee, Taik-Min; Kim, Inyoung; Choi, Kyung-Hyun

    2015-10-15

    Highlights: • Screen printing of silver pattern. • X-ray diffraction pattern confirmed the face centered cubic structure of silver. • Uniform surface morphology of silver pattern with sheet resistance of 0.06 Ω/sq. • The power conversion efficiency of fabricated solar cell is found to be 2.58%. - Abstract: The present work is mainly focused on replacement of the vacuum process for top electrode fabrication in organic solar cells. Silver top electrode deposited through solution based screen printing on pre-deposited polymeric thin film. The solution based printing technology provides uniform top electrode without damaging the underlying organic layers. The surface crystallinity and surface morphology of silver top electrode are examined through X-ray diffraction, field-emission scanning electron microscope and atomic force microscope. The purity of silver is examined through X-ray energy dispersive spectroscopy. The top electrode exhibits face centered cubic structure with homogeneous morphology. The sheet resistance of top electrode is found to be 0.06 Ω/sq and an average pattern thickness of ∼15 μm. The power conversion efficiency is 2.58%. Our work demonstrates that the solution based screen printing is a significant role in the replacement of vacuum process for the fabrication of top electrode in organic solar cells.

  19. Tevatron Top-Quark Combinations and World Top-Quark Mass Combination

    SciTech Connect

    Peters, Reinhild Yvonne

    2014-11-04

    Almost 20 years after its discovery, the top quark is still an interesting particle, undergoing precise investigation of its properties. For many years, the Tevatron proton antiproton collider at Fermilab was the only place to study top quarks in detail, while with the recent start of the LHC proton proton collider a top quark factory has opened. An important ingredient for the full understanding of the top quark is the combination of measurements from the individual experiments. In particular, the Tevaton combinations of single top-quark cross sections, the ttbar production cross section, the W helicity in top-quark decays as well as the Tevatron and the world combination of the top-quark mass are discussed.

  20. Growth of Staphylococcus aureus MF 31 on the Top and Cut Surfaces of Southern Custard Pies

    PubMed Central

    Preonas, D. L.; Nelson, A. I.; Ordal, Z. John; Steinberg, M. P.; Wei, L. S.

    1969-01-01

    A Staphylococcus strain was inoculated on the top and cut surfaces of freshly baked Southern custard pies which were then packaged in a pasteboard carton and held at 30 C. Daily plate counts of surface sections 0.3 inch (0.76 cm) in thickness were made. The top surface inoculum showed a 24-hr lag time. This was due to the protective action of a top cakelike layer as shown by homogenization of the mix and coating of the surface. Substitution of all sweeteners with dextrose completely inhibited growth on the top surface. Further addition of dextrose to lower water activity (Aw) to 0.9 prevented growth on the cut surface as well, but such pies were organoleptically unacceptable. Growth on the top surface could also be prevented by 80 μg of undissociated sorbic acid per g in combination with 100 μg of undissociated propionic acid per g in the baked pie. Growth on the cakelike top surface was always retarded longer than on the cut surface provided the packaging allowed evaporation of surface moisture. Reducing the Aw of a different type of cream pie to 0.907 prevented top surface growth. It was concluded that baked cream pies with a cakelike top layer could be marketed with a “refrigerate after opening” label, provided the package maintains the moisture gradient caused by the surface skin and either a combination of 80 μg of undissociated sorbic acid per g and 100 μg undissociated propionic acid per g is present in the baked pie or the Aw of the baked pie is 0.920 or lower. Images PMID:5803631

  1. Precision Determination of the Top Quark Mass

    SciTech Connect

    Movilla Fernandez, Pedro A.; /LBL, Berkeley

    2007-05-01

    The CDF and D0 collaborations have updated their measurements of the mass of the top quark using proton-antiproton collisions at {radical}s = 1.96 TeV produced at the Tevatron. The uncertainties in each of the top-antitop decay channels have been reduced. The new Tevatron average for the mass of the top quark based on about 1 fb{sup -1} of data per experiment is 170.9 {+-} 1.8 GeV/c{sup 2}.

  2. Single Top Quark Measurements at the Tevatron

    SciTech Connect

    Ronzani, Manfredi

    2014-12-01

    This paper reports the most recent measurements of single top quark production performed by CDF and D0 collaborations in proton-antiproton collisions at Tevatron. Events are selected in the lepton+jets final state by CDF and D0 and in the missing transverse energy plus jets final state by CDF. The small single top signal in s-channel, t-channel and inclusive s+t channel is separated from the large background by using different multivariate techniques. We also present the most recent results on extraction of the CKM matrix element $|V_{tb}|$ from the single top quark cross section.

  3. Top quark mass measurement at the Tevatron

    SciTech Connect

    Guimaraes da Costa, Joao; /Harvard U.

    2004-12-01

    The authors report on the latest experimental measurements of the top quark mass by the CDF and D0 Collaborations at the Fermilab Tevatron. They present a new top mass measurement using the t{bar t} events collected by the D0 Collaboration in Run I between 1994 and 1996. This result is combined with previous measurements to yield a new world top mass average. They also describe several preliminary results using up to 193 pb{sup -1} of t{bar t} events produced in {bar p}p collisions at {radical}s = 1.96 TeV during the Run II of the Tevatron.

  4. Top quark properties from the Tevatron

    SciTech Connect

    Klute, Markus; /MIT, LNS

    2006-05-01

    This report describes latest measurements and studies of top quark properties from the Tevatron in Run II with an integrated luminosity of up to 750 pb{sup -1}. Due to its large mass of about 172 GeV/c{sup 2}, the top quark provides a unique environment for tests of the Standard Model and is believed to yield sensitivity to new physics beyond the Standard Model. With data samples of close to 1 fb{sup -1} the CDF and D0 collaborations at the Tevatron enter a new area of precision top quark measurements.

  5. Multiresonant layered plasmonic films

    SciTech Connect

    DeVetter, Brent M.; Bernacki, Bruce E.; Bennett, Wendy D.; Schemer-Kohrn, Alan; Alvine, Kyle J.

    2017-01-01

    Multi-resonant nanoplasmonic films have numerous applications in areas such as nonlinear optics, sensing, and tamper indication. While techniques such as focused ion beam milling and electron beam lithography can produce high-quality multi-resonant films, these techniques are expensive, serial processes that are difficult to scale at the manufacturing level. Here, we present the fabrication of multi-resonant nanoplasmonic films using a layered stacking technique. Periodically-spaced gold nanocup substrates were fabricated using self-assembled polystyrene nanospheres followed by oxygen plasma etching and metal deposition via magnetron sputter coating. By adjusting etch parameters and initial nanosphere size, it was possible to achieve an optical response ranging from the visible to the near-infrared. Singly resonant, flexible films were first made by performing peel-off using an adhesive-coated polyolefin film. Through stacking layers of the nanofilm, we demonstrate fabrication of multi-resonant films at a fraction of the cost and effort as compared to top-down lithographic techniques.

  6. Turbulent boundary layer heat

    NASA Astrophysics Data System (ADS)

    Finson, M. L.; Clarke, A. S.; Wu, P. K. S.

    1981-01-01

    A Reynolds stress model for turbulent boundary layers is used to study surface roughness effects on skin friction and heat transfer. The issues of primary interest are the influence of roughness character (element shape and spacing) and the nature of roughness effects at high Mach numbers. Computations based on the model compare satisfactorily with measurements from experiments involving variations in roughness character, in low speed and modestly supersonic conditions. The more limited data base at hypersonic Mach numbers is also examined with reasonable success, although no quantitative explanation is offered for the reduction of heat transfer with increasing roughness observed by Holden at Me -9.4. The present calculations indicate that the mean velocity is approximately uniform over much of the height range below the tops of the elements, y less than or equal to k. With this constant (roughness velocity,) it is simple to estimate the form drag on the elements. This roughness velocity has been investigated by systematically exercising the present model over ranges of potential parameters. The roughness velocity is found to be primarily a function of the projected element frontal area per unit surface area, thus providing a new and simple method for predicting roughness character effects. The model further suggests that increased boundary layer temperatures should be generated by roughness at high edge Mach numbers, which would tend to reduce skin friction and heat transfer, perhaps below smooth wall levels.

  7. Environmental Instability and Degradation of Single- and Few-Layer WTe2 Nanosheets in Ambient Conditions.

    PubMed

    Ye, Fan; Lee, Jaesung; Hu, Jin; Mao, Zhiqiang; Wei, Jiang; Feng, Philip X-L

    2016-09-08

    Ambient environmental instability and degradation mechanism of single- and few-layer WTe2 are investigated. Oxidation of W and Te atoms appears to be a main reason for degradation. Single-layer samples' Raman signals disappear within 20 min in air. Few-layer WTe2 exhibits saturating degradation behavior: only the top layer WTe2 is oxidized; the degraded layer can protect inner layers from further degradation.

  8. Top Five Lifestyle Changes to Reduce Cholesterol

    MedlinePlus

    Top 5 lifestyle changes to improve your cholesterol Lifestyle changes can help reduce cholesterol, keep you off cholesterol-lowering medications or enhance the effect of your medications. Here are five lifestyle ...

  9. Higgs Effects in Top Quark Pair Production

    SciTech Connect

    Kuhn, J.H.

    2003-06-13

    Top quark production in p{bar p} and e{sup +}e{sup -} collisions is enhanced by the exchange of a Higgs boson. The enhancement factors are calculated in the threshold region using the Greens function method.

  10. Top Quark Physics at the Tevatron

    SciTech Connect

    Jung, Andreas W.

    2015-05-21

    An overview of recent top quark measurements using the full Run II data set of CDF or D0 at the Tevatron is presented. Results are complementary to the ones at the LHC. Recent measurements of the production cross section of top quarks in strong and electroweak production and of top quark production asymmetries are presented. The latter includes the measurement of the tt-bar production asymmetry by D0 in the dilepton decay channel. Within their uncertainties the results from all these measurements agree with their respective Standard Model expectation. Finally latest updates on measurements of the top quark mass are discussed, which at the time of the conference are the most precise determinations.

  11. Wind Energy Program: Top 10 Program Accomplishments

    SciTech Connect

    2009-01-18

    Brochure on the top accomplishments of the Wind Energy Program, including the development of large wind machines, small machines for the residential market, wind tunnel testing, computer codes for modeling wind systems, high definition wind maps, and successful collaborations.

  12. Dark decay of the top quark

    SciTech Connect

    Kong, Kyoungchul; Lee, Hye -Sung; Park, Myeonghun

    2014-04-01

    We suggest top quark decays as a venue to search for light dark force carriers. Top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6 σ deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t → b W + Z's. This is the same as the dominant top quark decay (t → b W) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. In addition, we discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.

  13. Top partner probes of extended Higgs sectors

    NASA Astrophysics Data System (ADS)

    Kearney, John; Pierce, Aaron; Thaler, Jesse

    2013-08-01

    Natural theories of the weak scale often include fermionic partners of the top quark. If the electroweak symmetry breaking sector contains scalars beyond a single Higgs doublet, then top partners can have sizable branching ratios to these extended Higgs sector states. In fact, top partner decays may provide the most promising discovery mode for such scalars, especially given the large backgrounds to direct and associated production. In this paper, we present a search strategy for top partner decays to a charged Higgs boson and a bottom quark, focusing on the case where the charged Higgs dominantly decays to third-generation quarks to yield a multi- b final state. We also discuss ways to extend this search to exotic neutral scalars decaying to bottom quark pairs.

  14. Top decays and mass with CDF

    SciTech Connect

    Barbaro-Galtieri, A.; CDF Collaboration

    1996-06-01

    The authors report preliminary results on top quark decays and measurements of the top mass recently obtained by the CDF collaboration, using a data sample of about 110 pb{sup {minus}1} collected at the Tevatron collider. Upper limits for non Standard model top decays into W + q (non b quark), Z + q and {gamma} + q are given. Top mass measurements are obtained in three topologies for t{anti t} production and decay into W b: lepton + {ge} 4 jets, di-lepton and all hadronic final states. The most precise measurement is obtained in the lepton + {ge} 4 jets topology using 34 events which have at least one jet tagged by the SVX or SLT b-tagging algorithms and a good constrained kinematics fit.

  15. Giving top quark effective operators a boost

    NASA Astrophysics Data System (ADS)

    Englert, Christoph; Moore, Liam; Nordström, Karl; Russell, Michael

    2016-12-01

    We investigate the prospects to systematically improve generic effective field theory-based searches for new physics in the top sector during LHC run 2 as well as the high luminosity phase. In particular, we assess the benefits of high momentum transfer final states on top EFT-fit as a function of systematic uncertainties in comparison with sensitivity expected from fully-resolved analyses focusing on t t bar production. We find that constraints are typically driven by fully-resolved selections, while boosted top quarks can serve to break degeneracies in the global fit. This demystifies and clarifies the importance of high momentum transfer final states for global fits to new interactions in the top sector from direct measurements.

  16. Best of "Earth As Art" -- Top Five

    NASA Video Gallery

    Counting down the Top Five Earth As Art images, as voted on by the public. Landsat has been collecting data of the Earth's surface since 1972. Some of the images are visually striking, and they hav...

  17. Green Power Partnership Top Partner Rankings

    EPA Pesticide Factsheets

    EPA's Green Power Partnership is a voluntary program designed to reduce the environmental impact of electricity generation by promoting renewable energy. Top Partner Rankings highlight the annual green power use of leading Green Power Partners.

  18. Green Power Partnership National Top 100

    EPA Pesticide Factsheets

    The U.S. EPA's Green Power Partnership is a voluntary program designed to reduce the environmental impact of electricity generation by promoting renewable energy. The National Top 100 lists the largest green power users within the Green Power Partnership.

  19. Top and higgs physics at the Tevatron

    SciTech Connect

    Pierre Savard

    2002-12-23

    We present a summary of our experimental understanding of the top quark and discuss the significant improvements expected in Run II at the Fermilab Tevatron Collider. We also discuss prospects for a Higgs boson discovery at the Tevatron.

  20. Review of recent top quark measurements

    SciTech Connect

    Heinson, A.P.; /UC, Riverside

    2004-11-01

    At the Tevatron Collider at Fermilab, a large number of top quarks have been produced in the ongoing run. The CDF and D0 collaborations have made first measurements of the t{bar t} cross section in several decay channels, and have measured the top quark mass. In addition, they have set new limits on the cross sections for single top quark production, and have started to measure some of the properties of the top quark via studies of its decays. This paper summarizes the status of these measurements and discusses where they are heading in the next few years. The paper is based on a talk I gave at the Rencontres du Vietnam in Hanoi, August 2004; the results have been updated to show the latest values and new measurements.

  1. Strained layer Fabry-Perot device

    DOEpatents

    Brennan, Thomas M.; Fritz, Ian J.; Hammons, Burrell E.

    1994-01-01

    An asymmetric Fabry-Perot reflectance modulator (AFPM) consists of an active region between top and bottom mirrors, the bottom mirror being affixed to a substrate by a buffer layer. The active region comprises a strained-layer region having a bandgap and thickness chosen for resonance at the Fabry-Perot frequency. The mirrors are lattice matched to the active region, and the buffer layer is lattice matched to the mirror at the interface. The device operates at wavelengths of commercially available semiconductor lasers.

  2. Tools for top physics at CDF

    SciTech Connect

    Palencia, E.; /Fermilab

    2008-07-01

    The authors describe here the different tools used for top physics analysis in the CDF Collaboration. In particular, they discuss how the jet energy scale, lepton identification, b tagging algorithms and the neural networks help to improve the signal to background ratio of the top sample in some cases and to reduce the dominant uncertainties in other. Results using each one of these tools are also presented.

  3. The Discovery of the Top Quark

    DOE R&D Accomplishments Database

    Sinervo, P.K.

    1995-12-01

    The top quark and the Higgs boson are the heaviest elementary particles predicted by the standard model. The four lightest quark flavours, the up, down, strange and charm quarks, were well-established by the mid-1970's. The discovery in 1977 of the {Tau} resonances, a new family of massive hadrons, required the introduction of the fifth quark flavour. Experimental and theoretical studies have indicated that this quark also has a heavier partner, the top quark.

  4. Development of N/P AlGaAs free-standing top solar cells for tandem applications

    NASA Technical Reports Server (NTRS)

    Negley, Gerald H.; Dinetta, Louis C.; Cummings, John R.; Hannon, Margaret H.; Sims, Paul E.; Barnett, Allen M.

    1991-01-01

    The combination of a free standing AlGaAs top solar cell and an existing bottom solar cell is the highest performance, lowest risk approach to implementing the tandem cell concept. The solar cell consists of an AlGaAs substrate layer, an AlGaAs base layer, an AlGaAs emitter, and an ultra-thin AlGaAs window layer. The window layer is compositionally graded which minimizes reflection at the window layer/emitter interface and creates a built-in electric field to improve quantum response in the blue region of the spectrum. Liquid phase epitaxy (LPE) is the only viable method to produce this free standing top solar cell. Small (0.125 sq cm), transparent p/n AlGaAs top solar cells were demonstrated with optimum bandgap for combination with a silicon bottom solar cell. The efficiency of an AlGaAs/Si stack using the free standing AlGaAs device upon an existing silicon bottom solar cell is 24 pct. (1X, Air Mass Zero (AM0). The n/p AlGaAs top solar cell is being developed in order to facilitate the wiring configuration. The two terminal tandem stack will retain fit, form, and function of existing silicon solar cells. Progress in the development of large area (8 and 16 sq cm), free standing AlGaAs top solar cells is discussed.

  5. Boundary Layer Parameterization for a Global Spectral Model

    DTIC Science & Technology

    1991-01-27

    assume an upside down structure with the main source of shear generation occurring near the top of the surface invesion layer (Mahrt, 1985). The local...1980: The structure of a fair weather boundary layer Nkcho!ls, S. based on the results of several inasuarement strategies . Mon. Wea. Rev., 108, 349-364

  6. Boundary layer flow visualisation patterns on a riblet surface

    NASA Astrophysics Data System (ADS)

    Clark, D. G.

    Boundary layer flow visualization methods, developed at Queen Mary and Westfield College, have been applied to a riblet surface. The results reveal cellular crossflows developing in the grooves between the riblets. These local flor regimes appear to have little direct effect on the flow in the wall layers immediately adjacent to them. Qualitatively, the behavior of the wall layers appears to be that which would be expected if a virtual surface existed at a level slightly above the riblet tops, but a tendency for the origin of longitudinal eddy pairs to become anchored to the top of a riblet is noted.

  7. Measurement of top quark polarisation in t-channel single top quark production

    DOE PAGES

    Khachatryan, Vardan

    2016-04-13

    Our first measurement of the top quark spin asymmetry, sensitive to the top quark polarisation, in t-channel single top quark production is presented. It is based on a sample of pp collisions at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7 fb-1. A high-purity sample of t-channel single top quark events with an isolated muon is selected. Signal and background components are estimated using a fit to data. Furthermore, a differential cross section measurement, corrected for detector effects, of an angular observable sensitive to the top quark polarisation is performed. The differential distribution is usedmore » to extract a top quark spin asymmetry of 0.26 ± 0.03 (stat) ± 0.10 (syst), which is compatible with a p-value of 4.6% with the standard model prediction of 0.44.« less

  8. Measurement of top quark polarisation in t-channel single top quark production

    SciTech Connect

    Khachatryan, Vardan

    2016-04-13

    Our first measurement of the top quark spin asymmetry, sensitive to the top quark polarisation, in t-channel single top quark production is presented. It is based on a sample of pp collisions at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7 fb-1. A high-purity sample of t-channel single top quark events with an isolated muon is selected. Signal and background components are estimated using a fit to data. Furthermore, a differential cross section measurement, corrected for detector effects, of an angular observable sensitive to the top quark polarisation is performed. The differential distribution is used to extract a top quark spin asymmetry of 0.26 ± 0.03 (stat) ± 0.10 (syst), which is compatible with a p-value of 4.6% with the standard model prediction of 0.44.

  9. Measurement of top quark polarisation in t-channel single top quark production

    NASA Astrophysics Data System (ADS)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Knünz, V.; König, A.; Krammer, M.; Krätschmer, I.; Liko, D.; Matsushita, T.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Cornelis, T.; de Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; van de Klundert, M.; van Haevermaet, H.; van Mechelen, P.; van Remortel, N.; van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; de Bruyn, I.; Deroover, K.; Heracleous, N.; Keaveney, J.; Lowette, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; van Doninck, W.; van Mulders, P.; van Onsem, G. P.; van Parijs, I.; Barria, P.; Brun, H.; Caillol, C.; Clerbaux, B.; de Lentdecker, G.; Fasanella, G.; Favart, L.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Léonard, A.; Maerschalk, T.; Marinov, A.; Perniè, L.; Randle-Conde, A.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Yonamine, R.; Zenoni, F.; Zhang, F.; Beernaert, K.; Benucci, L.; Cimmino, A.; Crucy, S.; Dobur, D.; Fagot, A.; Garcia, G.; Gul, M.; McCartin, J.; Ocampo Rios, A. A.; Poyraz, D.; Ryckbosch, D.; Salva, S.; Sigamani, M.; Tytgat, M.; van Driessche, W.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bondu, O.; Brochet, S.; Bruno, G.; Caudron, A.; Ceard, L.; da Silveira, G. G.; Delaere, C.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Mertens, A.; Musich, M.; Nuttens, C.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Beliy, N.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, F. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Hamer, M.; Hensel, C.; Mora Herrera, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; da Costa, E. M.; de Jesus Damiao, D.; de Oliveira Martins, C.; Fonseca de Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado da Silva, W. L.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; de Souza Santos, A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. H.; Plestina, R.; Romeo, F.; Shaheen, S. M.; Spiezia, A.; Tao, J.; Wang, C.; Wang, Z.; Zhang, H.; Asawatangtrakuldee, C.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Micanovic, S.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Bodlak, M.; Finger, M.; Finger, M.; Abdelalim, A. A.; Awad, A.; El Sawy, M.; Mahrous, A.; Radi, A.; Calpas, B.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Machet, M.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Zghiche, A.; Antropov, I.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Dahms, T.; Davignon, O.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Jo, M.; Lisniak, S.; Mastrolorenzo, L.; Miné, P.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Pigard, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Coubez, X.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Merlin, J. A.; Skovpen, K.

    2016-04-01

    A first measurement of the top quark spin asymmetry, sensitive to the top quark polarisation, in t-channel single top quark production is presented. It is based on a sample of pp collisions at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7 fb-1. A high-purity sample of t-channel single top quark events with an isolated muon is selected. Signal and background components are estimated using a fit to data. A differential cross section measurement, corrected for detector effects, of an angular observable sensitive to the top quark polarisation is performed. The differential distribution is used to extract a top quark spin asymmetry of 0.26 ± 0.03(stat) ± 0.10(syst), which is compatible with a p-value of 4.6% with the standard model prediction of 0.44. [Figure not available: see fulltext.

  10. Top Quark Properties in Little Higgs Models

    SciTech Connect

    Berger, C.F.; Perelstein, M.; Petriello, F.; /Wisconsin U., Madison

    2005-12-08

    Identifying the mechanism which breaks electroweak symmetry and generates fermion masses is one of the main physics goals for both the LHC and the ILC. Studies of the top quark have the potential to illuminate this issue; since it is the heaviest of the Standard Model (SM) fermions, the top is expected to couple strongly to the symmetry-breaking sector. Consequently, the structure of that sector can have significant, potentially observable effects on the properties of the top. for example, it is well known that the vector and axial t{bar t}Z form factors receive large corrections (of order 5-10%) in certain models of dynamical electroweak symmetry breaking [1]. At future colliders such as the LHC and the ILC, we will be able to pursue a program of precision top physics, similar to the program studying the Z at LEP and SLC. In this manuscript, they study the corrections to the top quark properties in ''Little Higgs'' models of electroweak symmetry breaking [2], and compare the expected deviations from the SM predictions with expected sensitivities of experiments at the LHC and the ILC. In the Little Higgs models, electroweak symmetry is driven by the radiative effects from the top sector, including the SM-like top and its heavy counterpart, a TeV-scale ''heavy top'' T. Probing this structure experimentally is quite difficult. While the LHC should be able to discover the T quark, its potential for studying its couplings is limited [3,4]. Direct production of the T will likely be beyond the kinematic reach of the ILC. However, we will show below that the corrections to the gauge couplings of the SM top, induced by its mixing with the T, will be observable at the ILC throughout the parameter range consistent with naturalness. Measuring these corrections will provide a unique window on the top sector of the Little Higgs. Many Little Higgs models have been proposed in the literature. We will consider two examples in this study, the ''Littlest Higgs'' model [5], and its

  11. Patternless light outcoupling enhancement method for top-emission organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Kim, Doo-Hoon; Lee, Ho-Nyeon

    2016-11-01

    An increase of 65% in the luminous flux of a top-emission organic light-emitting diode (TE-OLED) was obtained by fabricating a stacked N,N‧-bis(naphthalen-1-yl)-N,N‧-bis(phenyl)benzidine (NPB) (0.2 µm)/CaF2 (2.5 µm) light outcoupling layer on the TE-OLED. The high-refractive-index NPB layer extracted the trapped light energy in the TE-OLED for input into the light outcoupling layer and protected the top cathode of the TE-OLED from damage due to the CaF2 layer. The surface morphology of the CaF2 layer had an irregular shape consisting of randomly dispersed pyramids; the irregular structure scattered the waveguide mode energy into air. By combining the effects of the NPB and CaF2 layers, the external quantum efficiency of the TE-OLED was increased significantly. The light outcoupling layer can be fabricated using a thermal evaporation process without patterning and, hence, provides a practical solution for the enhancement of TE-OLED light outcoupling using a patternless fabrication process.

  12. Modeling the summertime Arctic cloudy boundary layer

    SciTech Connect

    Curry, J.A.; Pinto, J.O.; McInnes, K.L.

    1996-04-01

    Global climate models have particular difficulty in simulating the low-level clouds during the Arctic summer. Model problems are exacerbated in the polar regions by the complicated vertical structure of the Arctic boundary layer. The presence of multiple cloud layers, a humidity inversion above cloud top, and vertical fluxes in the cloud that are decoupled from the surface fluxes, identified in Curry et al. (1988), suggest that models containing sophisticated physical parameterizations would be required to accurately model this region. Accurate modeling of the vertical structure of multiple cloud layers in climate models is important for determination of the surface radiative fluxes. This study focuses on the problem of modeling the layered structure of the Arctic summertime boundary-layer clouds and in particular, the representation of the more complex boundary layer type consisting of a stable foggy surface layer surmounted by a cloud-topped mixed layer. A hierarchical modeling/diagnosis approach is used. A case study from the summertime Arctic Stratus Experiment is examined. A high-resolution, one-dimensional model of turbulence and radiation is tested against the observations and is then used in sensitivity studies to infer the optimal conditions for maintaining two separate layers in the Arctic summertime boundary layer. A three-dimensional mesoscale atmospheric model is then used to simulate the interaction of this cloud deck with the large-scale atmospheric dynamics. An assessment of the improvements needed to the parameterizations of the boundary layer, cloud microphysics, and radiation in the 3-D model is made.

  13. A top-down strategy for the synthesis of mesoporous Ba0.5Sr0.5Co0.8Fe0.2O3-δ as a cathode precursor for buffer layer-free deposition on stabilized zirconia electrolyte with a superior electrochemical performance

    NASA Astrophysics Data System (ADS)

    Su, Chao; Xu, Xiaomin; Chen, Yubo; Liu, Yu; Tadé, Moses O.; Shao, Zongping

    2015-01-01

    We develop a facile and effective top-down method for the fabrication of mesoporous Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) oxide with a high specific surface area (∼25 m2 g-1). The original BSCF is first synthesized by the simple EDTA-citric acid complexing method, and then treated in H2O2 to obtain the mesoporous BSCF. The structure and morphology of as-prepared BSCF power is systematically characterized by N2 adsorption/desorption isotherms, XRD, TEM, SEM and ICP techniques. A possible mechanism for the creation of mesoporous BSCF is proposed, in which Ba2+ and Sr2+ dissolve selectively from partial BSCF particles during the catalytic decomposition of H2O2. The electrochemical properties are investigated by the EIS and I-V test in the symmetrical cell and integrated single cell configurations, respectively. The interfacial reaction between BSCF electrode and YSZ electrolyte was suppressed successfully by using the BSCF with high specific surface area to decrease the sintering temperature (800 °C), thus the electrode exhibits high oxygen reduction reaction activity. The solid oxide fuel cell (SOFC) achieves an exciting peak power density of ∼1800 mW cm-2 at 800 °C, signifying the mesoporous BSCF, together with the preparation method, has a good application prospect in the development of SOFCs.

  14. Buffer layers on metal alloy substrates for superconducting tapes

    DOEpatents

    Jia, Quanxi; Foltyn, Stephen R.; Arendt, Paul N.; Groves, James R.

    2004-06-29

    An article including a substrate, a layer of an inert oxide material upon the surface of the substrate, a layer of an amorphous oxide or oxynitride material upon the inert oxide material layer, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the amorphous oxide material layer, and a layer of a SrRuO.sub.3 buffer material upon the oriented cubic oxide material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon the layer of a SrRuO.sub.3 buffer material layer. With a HTS top-layer of YBCO upon at least one layer of the SrRuO.sub.3 buffer material in such an article, J.sub.c 's of up to 1.3.times.10.sup.6 A/cm.sup.2 have been demonstrated with projected IC's of over 200 Amperes across a sample 1 cm wide.

  15. Production and decay of heavy top quarks

    SciTech Connect

    Kauffman, R.P.

    1989-08-01

    Experimental evidence indicates that the top quark exists and has a mass between 50 and 200 GeV/c{sup 2}. The decays of a top quark with a mass in this range are studied with emphasis placed on the mass region near the threshold for production of real W bosons. Topics discussed are: (1) possible enhancement of strange quark production when M{sub W} + m{sub s} < m{sub t} < M{sub W} + m{sub b}; (2) exclusive decays of T mesons to B and B{asterisk} mesons using the non-relativistic quark model; (3) polarization of intermediate W's in top quark decay as a source of information on the top quark mass. The production of heavy top quarks in an e{sup +}e{sup {minus}} collider with a center-of-mass energy of 2 TeV is studied. The effective-boson approximation for photons, Z{sup 0}'s and W's is reviewed and an analogous approximation for interfaces between photons and Z{sup 0}'s is developed. The cross sections for top quark pair production from photon-photon, photon-Z{sup 0}, Z{sup 0}Z{sup 0}, and W{sup +}W{sup {minus}} fusion are calculated using the effective-boson approximation. Production of top quarks along with anti-bottom quarks via {gamma}W{sup +} and Z{sup 0}W{sup +} fusion is studied. An exact calculation of {gamma}e{sup +} {yields} {bar {nu}}t{bar b} is made and compared with the effective-W approximation. 31 refs., 46 figs.

  16. Deep Convective Cloud Top Heights and Their Thermodynamic Control During CRYSTAL-FACE

    NASA Technical Reports Server (NTRS)

    Sherwood, Steven C.; Minnis, Patrick; McGill, Matthew

    2004-01-01

    Infrared (11 micron) radiances from GOES-8 and local radiosonde profiles, collected during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) in July 2002, are used to assess the vertical distribution of Florida-area deep convective cloud top height and test predictions as to its variation based on parcel theory. The highest infrared tops (Z(sub 11)) reached approximately to the cold point, though there is at least a 1-km uncertainty due to unknown cloud-environment temperature differences. Since lidar shows that visible 'tops' are 1 km or more above Z(sub 11), visible cloud tops frequently penetrated the lapse-rate tropopause (approx. 15 km). Further, since lofted ice content may be present up to approx. 1 km above the visible tops, lofting of moisture through the mean cold point (15.4 km) was probably common. Morning clouds, and those near Key West, rarely penetrated the tropopause. Non-entraining parcel theory (i.e., CAPE) does not successfully explain either of these results, but can explain some of the day-to-day variations in cloud top height over the peninsula. Further, moisture variations above the boundary layer account for most of the day-today variability not explained by CAPE, especially over the oceans. In all locations, a 20% increase in mean mixing ratio between 750 and 500 hPa was associated with about 1 km deeper maximum cloud penetration relative to the neutral level. These results suggest that parcel theory may be useful for predicting changes in cumulus cloud height over time, but that parcel entrainment must be taken into account even for the tallest clouds. Accordingly, relative humidity above the boundary layer may exert some control on the height of the tropical troposphere.

  17. Covalent Fusion of layered Incompatible Gels in Immiscible Solvents

    NASA Astrophysics Data System (ADS)

    Biswas, Santidan; Singh, Awaneesh; Matyjaszewski, Krzysztof; Balazs, Anna C.

    We carry out dissipative particle dynamics (DPD) simulations to model a two layered stackable gel where the gels are incompatible and are present in immiscible solvent. The bottom layer of the gel is created first and then a solution of new initiators, monomers and cross-linkers is introduced on top of it. These components then undergo polymerization and form the second gel layer. We study all possible combinations of free radical polymerization (FRP) and atom transfer radical polymerization (ATRP) mechanisms with the two layers of the gel. For example, the bottom layer gel is created via ATRP, whereas the top layer gel follows FRP. Our focus is to do a systematic study of all these combinations and find out the factors responsible for combining two incompatible gels in immiscible solvents.

  18. The retrieval of cloud-top pressure of multilayer clouds using combined measurements of MERIS and AATSR onboard ENVISAT

    NASA Astrophysics Data System (ADS)

    Lindstrot, R.; Preusker, R.; Fischer, J.

    2009-04-01

    Measurements of the Medium Resolution Imaging Spectrometer (MERIS) within the oxygen A band at 762nm are operationally used for the retrieval of cloud-top pressure. A validation with airborne LIDAR measurements revealed a high accuracy (~25hPa) of the cloud-top pressure product in case of low, single-layer clouds. However, problems arise in presence of multilayered clouds, as the single channel within the oxygen A band does not allow the identification of multiple cloud layers. The retrieved cloud height thus represents the effective single layer height, located in-between the true cloud layers. This problem can be resolved by combining MERIS observations with measurements in the thermal infrared spectral range. Since clouds are strongly absorbing at infrared wavelengths, the cloud-top temperature of even optically thin clouds can be determined and related to cloud-top pressure using the respective temperature profile. The Advanced Along Track Scanning Radiometer (AATSR) onboard ENVISAT provides radiance measurements in the thermal infrared region that can easily be combined with MERIS observations, as both are nadir viewing, imaging instruments with a similar spatial resolution of ~1km. The synergetic measurements can be used for the retrieval of the height of two cloud layers in case the upper layer is optically thin (? ? 5). The retrieval algorithm is based on the Optimal Estimation technique using radiative transfer simulations of the Matrix Operator Model (MOMO).

  19. Self-aligned imprint lithography for top-gate amorphous silicon thin-film transistor fabrication

    NASA Astrophysics Data System (ADS)

    Lausecker, E.; Huang, Y.; Fromherz, T.; Sturm, J. C.; Wagner, S.

    2010-06-01

    We developed self-aligned imprint lithography (SAIL) for top-gate amorphous silicon (a-Si) thin-film transistors (TFTs). Our SAIL process enables a device pattern definition in a single imprint step that uses a three-level mold. The various levels of the mold are defined by a stepwise opening of a chromium hardmask and subsequent dry-etching. For TFT fabrication we imprint, and consecutively etch the imprint resist levels and device layers. The imprinted top-gate a-Si TFTs have nickel silicide source/drain self-aligned to the gate with mobilities of ˜0.4 cm2/V s.

  20. Surface layering properties of Intralipid phantoms.

    PubMed

    Bodenschatz, Nico; Krauter, Philipp; Foschum, Florian; Nothelfer, Steffen; Liemert, André; Simon, Emanuel; Kröner, Sabrina; Kienle, Alwin

    2015-02-07

    Intralipid has become an extensively studied and widely used reference and calibration phantom for diffuse optical imaging technologies. In this study we call attention to the layering properties of Intralipid emulsions, which are commonly assumed to have homogeneous optical properties. By measurement of spatial frequency domain reflectance in combination with an analytical solution of the radiative transfer equation for two-layered media, we make quantitative investigations on the formation of a surface layer on different dilutions of Intralipid. Our findings are verified by an independent spatially resolved reflectance setup giving evidence of a time dependent, thin and highly scattering surface layer on top of Intralipid-water emulsions. This layer should be considered when using Intralipid as an optical calibration or reference phantom.

  1. Surface layering properties of Intralipid phantoms

    NASA Astrophysics Data System (ADS)

    Bodenschatz, Nico; Krauter, Philipp; Foschum, Florian; Nothelfer, Steffen; Liemert, André; Simon, Emanuel; Kröner, Sabrina; Kienle, Alwin

    2015-02-01

    Intralipid has become an extensively studied and widely used reference and calibration phantom for diffuse optical imaging technologies. In this study we call attention to the layering properties of Intralipid emulsions, which are commonly assumed to have homogeneous optical properties. By measurement of spatial frequency domain reflectance in combination with an analytical solution of the radiative transfer equation for two-layered media, we make quantitative investigations on the formation of a surface layer on different dilutions of Intralipid. Our findings are verified by an independent spatially resolved reflectance setup giving evidence of a time dependent, thin and highly scattering surface layer on top of Intralipid-water emulsions. This layer should be considered when using Intralipid as an optical calibration or reference phantom.

  2. Top Stars: An Opportunity for Educators

    NASA Astrophysics Data System (ADS)

    Kinnison, S. M. P.

    2010-08-01

    Think you're a Top Star? Want to find out what it takes? Learn about NASA's Top Stars contest and how you can participate. Throughout its lifetime, the Hubble Space Telescope has inspired and promoted education. The final Hubble servicing mission in May of this year and the celebration of Hubble's 20th anniversary in 2010 are key mission milestones, and both enrich activities for the 2009 International Year of Astronomy. U.S. formal (K-12 and college) and informal educators are invited to submit their best examples of using NASA's Hubble Space Telescope for science, technology, engineering or mathematics education. Those selected as Top Stars will receive national recognition and awards. Participants will learn about the contest, the recognition and awards, and how to register and save their entries on the Top Stars Web site. Educators are allowed and encouraged to revise, improve and re-submit their entries up to the final deadline of January 2, 2010. The contest is open to individuals and teams of up to four people who are U.S. citizens and are at least 21 years old. NASA and Institute for Global Environmental Strategies (IGES) employees or their contractors are not eligible. IGES is conducting Top Stars with NASA funding and in cooperation with the Space Telescope Science Institute.

  3. Towards the Top with D0

    SciTech Connect

    Deliot, Frederic

    2012-01-01

    The plan of this manuscript follows my research path over the past 10 years: the muon identification and common analysis tools at DØ, the measurement of the inclusive production of W boson decaying into muon and top quark studies. In the first section, I describe my work about muon identification, certification of the standard muon identification criteria, measurement of the muon selection efficiency and about the development of common analysis format and tools. In the second section, I explain how these efficiency measurements can be used to measure the inclusive W boson production cross section in the muon channel. The W ! μν cross section measurement can be seen as a standard candle to establish several analysis pieces that have to be put in place to perform more complex measurements like top quark analyses. In the last section I introduce more extensively the top quark physics at the Tevatron and describe in more details the main analyses in the dilepton channel I was involved in: the measurement of the tt inclusive cross section in the dilepton channel as well as the ratio of cross sections, the measurement of the top quark mass in the dilepton channel, the extraction of the mass from the tt cross section and the Tevatron top quark mass combination. Before concluding, I finish the section with the description of the latest results on the tt charge asymmetry both at the Tevatron and at the LHC.

  4. Contact mechanics for layered materials with randomly rough surfaces.

    PubMed

    Persson, B N J

    2012-03-07

    The contact mechanics model of Persson is applied to layered materials. We calculate the M function, which relates the surface stress to the surface displacement, for a layered material, where the top layer (thickness d) has different elastic properties than the semi-infinite solid below. Numerical results for the contact area as a function of the magnification are presented for several cases. As an application, we calculate the fluid leak rate for laminated rubber seals.

  5. Double Layers in Astrophysics

    NASA Technical Reports Server (NTRS)

    Williams, Alton C. (Editor); Moorehead, Tauna W. (Editor)

    1987-01-01

    Topics addressed include: laboratory double layers; ion-acoustic double layers; pumping potential wells; ion phase-space vortices; weak double layers; electric fields and double layers in plasmas; auroral double layers; double layer formation in a plasma; beamed emission from gamma-ray burst source; double layers and extragalactic jets; and electric potential between plasma sheet clouds.

  6. Minimizing optical losses in monolithic perovskite/c-Si tandem solar cells with a flat top cell.

    PubMed

    Santbergen, Rudi; Mishima, Ryota; Meguro, Tomomi; Hino, Masashi; Uzu, Hisashi; Blanker, Johan; Yamamoto, Kenji; Zeman, Miro

    2016-09-05

    In a monolithic perovskite/c-Si tandem device, the perovskite top cell has to be deposited onto a flat c-Si bottom cell without anti-reflective front side texture, to avoid fabrication issues. We use optical simulations to analyze the reflection losses that this induces. We then systematically minimize these losses by introducing surface textures in combination with a so-called burial layer to keep the perovskite top cell flat. Optical simulations show that, even with a flat top cell, the monolithic perovskite/c-Si tandem device can reach a matched photocurrent density as high as 19.57 mA/cm2.

  7. Verification of a two-layer inverse Monte Carlo absorption model using multiple source-detector separation diffuse reflectance spectroscopy.

    PubMed

    Sharma, Manu; Hennessy, Ricky; Markey, Mia K; Tunnell, James W

    2013-12-02

    A two-layer Monte Carlo lookup table-based inverse model is validated with two-layered phantoms across physiologically relevant optical property ranges. Reflectance data for source-detector separations of 370 μm and 740 μm were collected from these two-layered phantoms and top layer thickness, reduced scattering coefficient and the top and bottom layer absorption coefficients were extracted using the inverse model and compared to the known values. The results of the phantom verification show that this method is able to accurately extract top layer thickness and scattering when the top layer thickness ranges from 0 to 550 μm. In this range, top layer thicknesses were measured with an average error of 10% and the reduced scattering coefficient was measured with an average error of 15%. The accuracy of top and bottom layer absorption coefficient measurements was found to be highly dependent on top layer thickness, which agrees with physical expectation; however, within appropriate thickness ranges, the error for absorption properties varies from 12-25%.

  8. Verification of a two-layer inverse Monte Carlo absorption model using multiple source-detector separation diffuse reflectance spectroscopy

    PubMed Central

    Sharma, Manu; Hennessy, Ricky; Markey, Mia K.; Tunnell, James W.

    2013-01-01

    A two-layer Monte Carlo lookup table-based inverse model is validated with two-layered phantoms across physiologically relevant optical property ranges. Reflectance data for source-detector separations of 370 μm and 740 μm were collected from these two-layered phantoms and top layer thickness, reduced scattering coefficient and the top and bottom layer absorption coefficients were extracted using the inverse model and compared to the known values. The results of the phantom verification show that this method is able to accurately extract top layer thickness and scattering when the top layer thickness ranges from 0 to 550 μm. In this range, top layer thicknesses were measured with an average error of 10% and the reduced scattering coefficient was measured with an average error of 15%. The accuracy of top and bottom layer absorption coefficient measurements was found to be highly dependent on top layer thickness, which agrees with physical expectation; however, within appropriate thickness ranges, the error for absorption properties varies from 12–25%. PMID:24466475

  9. The Keck keyword layer

    NASA Technical Reports Server (NTRS)

    Conrad, A. R.; Lupton, W. F.

    1992-01-01

    Each Keck instrument presents a consistent software view to the user interface programmer. The view consists of a small library of functions, which are identical for all instruments, and a large set of keywords, that vary from instrument to instrument. All knowledge of the underlying task structure is hidden from the application programmer by the keyword layer. Image capture software uses the same function library to collect data for the image header. Because the image capture software and the instrument control software are built on top of the same keyword layer, a given observation can be 'replayed' by extracting keyword-value pairs from the image header and passing them back to the control system. The keyword layer features non-blocking as well as blocking I/O. A non-blocking keyword write operation (such as setting a filter position) specifies a callback to be invoked when the operation is complete. A non-blocking keyword read operation specifies a callback to be invoked whenever the keyword changes state. The keyword-callback style meshes well with the widget-callback style commonly used in X window programs. The first keyword library was built for the two Keck optical instruments. More recently, keyword libraries have been developed for the infrared instruments and for telescope control. Although the underlying mechanisms used for inter-process communication by each of these systems vary widely (Lick MUSIC, Sun RPC, and direct socket I/O, respectively), a basic user interface has been written that can be used with any of these systems. Since the keyword libraries are bound to user interface programs dynamically at run time, only a single set of user interface executables is needed. For example, the same program, 'xshow', can be used to display continuously the telescope's position, the time left in an instrument's exposure, or both values simultaneously. Less generic tools that operate on specific keywords, for example an X display that controls optical

  10. Multi-layer carbon-based coatings for field emission

    DOEpatents

    Sullivan, John P.; Friedmann, Thomas A.

    1998-01-01

    A multi-layer resistive carbon film field emitter device for cold cathode field emission applications. The multi-layered film of the present invention consists of at least two layers of a conductive carbon material, preferably amorphous-tetrahedrally coordinated carbon, where the resistivities of adjacent layers differ. For electron emission from the surface, the preferred structure can be a top layer having a lower resistivity than the bottom layer. For edge emitting structures, the preferred structure of the film can be a plurality of carbon layers, where adjacent layers have different resistivities. Through selection of deposition conditions, including the energy of the depositing carbon species, the presence or absence of certain elements such as H, N, inert gases or boron, carbon layers having desired resistivities can be produced.

  11. Multi-layer carbon-based coatings for field emission

    DOEpatents

    Sullivan, J.P.; Friedmann, T.A.

    1998-10-13

    A multi-layer resistive carbon film field emitter device for cold cathode field emission applications is disclosed. The multi-layered film of the present invention consists of at least two layers of a conductive carbon material, preferably amorphous-tetrahedrally coordinated carbon, where the resistivities of adjacent layers differ. For electron emission from the surface, the preferred structure can be a top layer having a lower resistivity than the bottom layer. For edge emitting structures, the preferred structure of the film can be a plurality of carbon layers, where adjacent layers have different resistivities. Through selection of deposition conditions, including the energy of the depositing carbon species, the presence or absence of certain elements such as H, N, inert gases or boron, carbon layers having desired resistivities can be produced. 8 figs.

  12. Top B physics at the LHC.

    PubMed

    Gedalia, Oram; Isidori, Gino; Maltoni, Fabio; Perez, Gilad; Selvaggi, Michele; Soreq, Yotam

    2013-06-07

    In top-pair events where at least one of the tops decays semileptonically, the identification of the lepton charge allows us to tag not only the top quark charge but also that of the subsequent b quark. In cases where the b also decays semileptonically, the charge of the two leptons can be used to probe CP violation in heavy flavor mixing and decays. This strategy to measure CP violation is independent of those adopted so far in experiments, and can already constrain non standard model sources of CP violation with current and near future LHC data. To demonstrate the potential of this method we construct two CP asymmetries based on same-sign and opposite-sign leptons and estimate their sensitivities. This proposal opens a new window for doing precision measurements of CP violation in b and c quark physics via high p(T) processes at ATLAS and CMS.

  13. CDF top quark production and mass

    SciTech Connect

    Incandela, J.; CDF Collaboration

    1995-07-18

    The top search in the dilepton and lepton plus jets channels with the Collider Detector at Fermilab is presented. The analysis uses a 67 pb{sup {minus}1} sample of p{bar p} collisions at 1.8 TeV. A 4.8{sigma} excess of candidate events establishes the existence of the top quark. The t{bar t} production cross section is measured to be {sigma}{sub t{bar t}} = 7.6{sub {minus}2.0}{sup +2.4} pb with branching Br(t {yields} Wb) = 0.87{sub {minus}0.30}{sup +0.13}(stat) {sub {minus}0.11}{sup +0.13}(syst). The measured mass is M{sub top} = 176{plus_minus}8{plus_minus}10 GeV.

  14. The Multiple Mirror Telescope (MMT) top box

    NASA Astrophysics Data System (ADS)

    Blanco, Daniel R.; Janes, Clinton C.; Montgomery, John W.; Ouellette, David B.; Sharp, Frank H.

    1986-01-01

    So named because it resides on top of the focal plane instrument, the MMT top box is a two-level optical bench with many remotely controlled features which can be configured for experimental use of the MMT. It houses the relay optics and television cameras for focusing, coaligning and guiding the six telescopes of the MMT, as well as the integrating sphere, filter wheel, Hartmann mask wheel, and relay optics of the comparison source for instrumental calibration. It also provides a rigid mounting platform for research instruments as well as special fixtures for telescope tests and collimation. In accommodating these tasks the top box incorporates several novel features which may interest designers of other large telescopes.

  15. Top2 and Sgs1-Top3 Act Redundantly to Ensure rDNA Replication Termination

    PubMed Central

    Fredsøe, Jacob; Nielsen, Ida; Pedersen, Jakob Madsen; Bentsen, Iben Bach; Lisby, Michael; Bjergbaek, Lotte; Andersen, Anni H

    2015-01-01

    Faithful DNA replication with correct termination is essential for genome stability and transmission of genetic information. Here we have investigated the potential roles of Topoisomerase II (Top2) and the RecQ helicase Sgs1 during late stages of replication. We find that cells lacking Top2 and Sgs1 (or Top3) display two different characteristics during late S/G2 phase, checkpoint activation and accumulation of asymmetric X-structures, which are both independent of homologous recombination. Our data demonstrate that checkpoint activation is caused by a DNA structure formed at the strongest rDNA replication fork barrier (RFB) during replication termination, and consistently, checkpoint activation is dependent on the RFB binding protein, Fob1. In contrast, asymmetric X-structures are formed independent of Fob1 at less strong rDNA replication fork barriers. However, both checkpoint activation and formation of asymmetric X-structures are sensitive to conditions, which facilitate fork merging and progression of replication forks through replication fork barriers. Our data are consistent with a redundant role of Top2 and Sgs1 together with Top3 (Sgs1-Top3) in replication fork merging at rDNA barriers. At RFB either Top2 or Sgs1-Top3 is essential to prevent formation of a checkpoint activating DNA structure during termination, but at less strong rDNA barriers absence of the enzymes merely delays replication fork merging, causing an accumulation of asymmetric termination structures, which are solved over time. PMID:26630413

  16. Top-down vortices developed in a cylindrical annulus cooled on the top.

    PubMed

    Navarro, M C; Herrero, H

    2013-07-01

    In this paper we study the generation of top-down vortices by thermoconvective mechanisms in a cylindrical annulus nonhomogeneously cooled on the top. Assuming axisymmetry we study the structure of the vortices, characterized by a spiral downward motion, similar to that observed in tornadoes generated in supercell storms.

  17. An Efficiency Comparison of MBA Programs: Top 10 versus Non-Top 10

    ERIC Educational Resources Information Center

    Hsu, Maxwell K.; James, Marcia L.; Chao, Gary H.

    2009-01-01

    The authors compared the cohort group of the top-10 MBA programs in the United States with their lower-ranking counterparts on their value-added efficiency. The findings reveal that the top-10 MBA programs in the United States are associated with statistically higher average "technical and scale efficiency" and "scale efficiency", but not with a…

  18. Ozone Layer Protection

    MedlinePlus

    ... EPA United States Environmental Protection Agency Search Search Ozone Layer Protection Share Facebook Twitter Google+ Pinterest Contact Us Ozone Layer Protection Welcome to EPA's ozone layer protection web ...

  19. A measurement of the top quark's charge

    SciTech Connect

    Unalan, Zeynep Gunay

    2007-01-01

    The top quark was discovered in 1995 at the Fermilab National Accelerator Laboratory (Fermilab). One way to confirm if the observed top quark is really the top quark posited in the Standard Model (SM) is to measure its electric charge. In the Standard Model the top quark is the isospin partner of the bottom quark and is expected to have a charge of +2/3. However, an alternative 'exotic' model has been proposed with a fourth generation exotic quark that has the same characteristics, such as mass, as our observed top but with a charge of -4/3. This thesis presents the first CDF measurement of the top quark's charge via its decay products, a W boson and a bottom quark, using ~ 1 fb-1 of data. The data were collected by the CDF detector from proton anti-proton (p$\\bar{p}$) collisions at √s = 1.96 TeV at Fermilab. We classify events depending on the charges of the bottom quark and associated W boson and count the number of events which appear 'SM-like' or 'exotic-like' with a SM-like event decaying as t → W+b and an exotic event as t → W-b. We find the p-value under the Standard Model hypothesis to be 0.35 which is consistent with the Standard Model. We exclude the exotic quark hypothesis at an 81% confidence level, for which we have chosen a priori that the probability of incorrectly rejecting the SM would be 1%. The calculated Bayes Factor (BF) is 2 x Ln(BF)=8.54 which is interpreted as the data strongly favors the Standard Model over the exotic quark hypothesis.

  20. A Two-layer Model for the Simulation of the VARTM Process with Resin Distribution Layer

    NASA Astrophysics Data System (ADS)

    Young, Wen-Bin

    2013-12-01

    Vacuum assisted resin transfer molding (VARTM) is one of the important processes to fabricate high performance composites. In this process, resin is drawn into the mold to impregnate the fiber reinforcement to a form composite. A resin distribution layer with high permeability was often introduced on top of the fiber reinforcement to accelerate the filling speed. Due to the difference of the flow resistance in the resin distribution layer and the reinforcement as well as the resulting through thickness transverse flow, the filling flow field is intrinsically three-dimensional. This study developed a two-layer model with two-dimensional formulation to simulate the filling flow of the VARTM process with a resin distribution layer. Two-dimensional flow was considered in each layer and a transverse flow in the thickness direction was estimated between the two layers. Thermal analysis including the transverse convection was also performed to better simulate the temperature distribution.

  1. Top Quark Spin Correlations at the Tevatron

    SciTech Connect

    Head, Tim; /Manchester U.

    2010-07-01

    Recent measurements of the correlation between the spin of the top and the spin of the anti-top quark produced in proton anti-proton scattering at a center of mass energy of {radical}s = 1.96 Tev by the CDF and D0 collaborations are discussed. using up to 4.3 fb{sup -1} of data taken with the CDF and D0 detectors the spin correlation parameter C, the degree to which the spins are correlated, is measured in dileptonic and semileptonic final states. The measurements are found to be in agreement with Standard Model predictions.

  2. Top and Electroweak Measurements at the Tevatron

    SciTech Connect

    Bartos, P.

    2016-01-01

    In this report, we summarize the latest results of the top-quark mass and electroweak measurements from the Tevatron. Since the world combination of top-quark mass measurements was done, CDF and D0 experiments improved the precision of several results. Some of them reach the relative precition below 1% for a single measurement. From the electroweak results, we report on the WW and WZ production cross section, measurements of the weak mixing angle and indirect measurements of W boson mass. The Tevatron results of the weak mixing angle are still the most precise ones of hadron colliders.

  3. Evidence for production of single top quarks

    SciTech Connect

    Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Aguilo, E.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; /St. Petersburg, INP /Michigan U.

    2008-03-01

    We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron p{bar p} collider. The standard model predicts that the electroweak interaction can produce a top quark together with an antibottom quark or light quark, without the antiparticle top quark partner that is always produced from strong coupling processes. Top quarks were first observed in pair production in 1995, and since then, single top quark production has been searched for in ever larger datasets. In this analysis, we select events from a 0.9 fb{sup -1} dataset that have an electron or muon and missing transverse energy from the decay of a W boson from the top quark decay, and two, three, or four jets, with one or two of the jets identified as originating from a b hadron decay. The selected events are mostly backgrounds such as W+jets and t{bar t} events, which we separate from the expected signals using three multivariate analysis techniques: boosted decision trees, Bayesian neural networks, and matrix element calculations. A binned likelihood fit of the signal cross section plus background to the data from the combination of the results from the three analysis methods gives a cross section for single top quark production of {sigma}(p{bar p} {yields} tb + X, tqb + X) = 4.7 {+-} 1.3 pb. The probability to measure a cross section at this value or higher in the absence of signal is 0.014%, corresponding to a 3.6 standard deviation significance. The measured cross section value is compatible at the 10% level with the standard model prediction for electroweak top quark production. We use the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa quark mixing matrix element that describes the Wtb coupling and find |V{sub tb}f{sub 1}{sup L}| = 1.31{sub -0.21}{sup +0.25}, where f{sub 1}{sup L} is a generic vector coupling. This model-independent measurement translates into 0.68 < |V{sub tb}| {le} 1 at the 95% C.L. in the standard model.

  4. Evidence for production of single top quarks

    SciTech Connect

    Abazov, V. M.; Alexeev, G. D.; Kalinin, A. M.; Kharzheev, Y. M.; Malyshev, V. L.; Tokmenin, V. V.; Vertogradov, L. S.; Yatsunenko, Y. A.; Abbott, B.; Gutierrez, P.; Hossain, S.; Jain, S.; Rominsky, M.; Severini, H.; Skubic, P.; Strauss, M.; Abolins, M.; Benitez, J. A.; Brock, R.; Dyer, J.

    2008-07-01

    We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron pp collider. The standard model predicts that the electroweak interaction can produce a top quark together with an antibottom quark or light quark, without the antiparticle top-quark partner that is always produced from strong-coupling processes. Top quarks were first observed in pair production in 1995, and since then, single top-quark production has been searched for in ever larger data sets. In this analysis, we select events from a 0.9 fb{sup -1} data set that have an electron or muon and missing transverse energy from the decay of a W boson from the top-quark decay, and two, three, or four jets, with one or two of the jets identified as originating from a b hadron decay. The selected events are mostly backgrounds such as W+jets and tt events, which we separate from the expected signals using three multivariate analysis techniques: boosted decision trees, Bayesian neural networks, and matrix-element calculations. A binned likelihood fit of the signal cross section plus background to the data from the combination of the results from the three analysis methods gives a cross section for single top-quark production of {sigma}(pp{yields}tb+X,tqb+X)=4.7{+-}1.3 pb. The probability to measure a cross section at this value or higher in the absence of signal is 0.014%, corresponding to a 3.6 standard deviation significance. The measured cross section value is compatible at the 10% level with the standard model prediction for electroweak top-quark production. We use the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa quark mixing matrix element that describes the Wtb coupling and find |V{sub tb}f{sub 1}{sup L}|=1.31{sub -0.21}{sup +0.25}, where f{sub 1}{sup L} is a generic vector coupling. This model-independent measurement translates into 0.68<|V{sub tb}|{<=}1 at the 95% C.L. in the standard model.

  5. Thermionic Energy Conversion (TEC) topping thermoelectrics

    NASA Technical Reports Server (NTRS)

    Morris, J. F.

    1981-01-01

    Performance expectations for thermionic and thermoelectric energy conversion systems are reviewed. It is noted that internal radiation effects diminish thermoelectric figures of merit significantly at 1000 K and substantially at 2000 K; the effective thermal conductivity contribution of intrathermoelectric radiative dissipation increases with the third power of temperature. It is argued that a consideration of thermoelectric power generation with high temperature heat sources should include utilization of thermionic energy conversion (TEC) topping thermoelectrics. However TEC alone or TEC topping more efficient conversion systems like steam or gas turbines, combined cycles, or Stirling engines would be more desirable generally.

  6. Measurement of the Top Quark Mass

    SciTech Connect

    Blair, R.E.; Byrum, K.L.; Kovacs, E.; Kuhlmann, S.E.; LeCompte, T.; Nodulman, L.; Breccia, L.; Brunetti, R.; Deninno, M.; Fiori, I.; Mazzanti, P.; Behrends, S.; Bensinger, J.; Blocker, C.; Kirsch, L.; Lamoureux, J.I.; Bonushkin, Y.; Hauser, J.; Lindgren, M.; Amadon, A.; Berryhill, J.; Contreras, M.; Culbertson, R.; Frisch, H.; Grosso-Pilcher, C.; Hohlmann, M.; Cronin-Hennessy, D.; Dittmann, J.R.; Goshaw, A.T.; Khazins, D.; Kowald, W.; Oh, S.H.; Albrow, M.G.; Atac, M.; Beretvas, A.; Berge, J.P.; Biery, K.; Binkley, M.; Buckley-Geer, E.; Byon-Wagner, A.; Chlebana, F.; Cihangir, S.; Cooper, J.; DeJongh, F.; Demina, R.; Derwent, P.F.; Elias, J.E.; Erdmann, W.; Flaugher, B.; Foster, G.W.; Freeman, J.; Geer, S.; Hahn, S.R.; Harris, R.M.; Incandela, J.; Jensen, H.; Joshi, U.; Kennedy, R.D.; Kephart, R.; Lammel, S.; Lewis, J.D.; Limon, P.; Lukens, P.; Maeshima, K.; Marriner, J.P.; Miao, T.; Mukherjee, A.; Nelson, C.; Newman-Holmes, C.; Patrick, J.; Klimenko, S.; Konigsberg, J.; Korytov, A.; Nomerotski, A.; Barone, M.; Bertolucci, S.; Cordelli, M.; DellAgnello, S.; Giromini, P.; Happacher, F.; Miscetti, S.; Parri, A.; Clark, A.G.; Couyoumtzelis, C.; Kambara, H.; Baumann, T.; Franklin, M.; Gordon, A.; Hamilton, R.; Huth, J.; and others

    1998-03-01

    We present a measurement of the top quark mass using a sample of t{bar t} decays into an electron or a muon, a neutrino, and four jets. The data were collected in p{bar p} collisions at {radical}(s)=1.8 TeV with the Collider Detector at Fermilab and correspond to an integrated luminosity of 109 pb{sup {minus}1} . We measure the top quark mass to be 175.9{plus_minus}4.8(stat){plus_minus}4.9( syst) GeV /c{sup 2} . {copyright} {ital 1998} {ital The American Physical Society}

  7. Total on-line purchasing system (TOPS)

    SciTech Connect

    Collins, N.

    1995-11-01

    The Information Management Division (IMD) at LLNL is developing a new purchasing system for the Procurement Department. The first major development of this new system is called, {open_quotes}Total On-Line Purchasing System{close_quotes} (TOPS). TOPS will help speed up the requisitioning process by having requisitions electronically entered by requesters and electronically sent to buyers to be put on Purchase Orders. The new purchasing system will use Electronic Commerce (EC)/Electronic Data Interchange (EDI), to help increase transaction flows for shipping notices, RFQs, Quotes, Purchase Orders, and Invoices. ANSI X.12 is the EDI standard that this new EC will use.

  8. Observation of Single Top Quark Production

    SciTech Connect

    Heinson, Ann; Junk, Tom R.; /Fermilab

    2011-01-01

    The field of experimental particle physics has become more sophisticated over time, as fewer, larger experimental collaborations search for small signals in samples with large components of background. The search for and the observation of electroweak single top quark production by the CDF and D0 collaborations at Fermilab's Tevatron collider are an example of an elaborate effort to measure the rate of a very rare process in the presence of large backgrounds and to learn about the properties of the top quark's weak interaction. We present here the techniques used to make this groundbreaking measurement and the interpretation of the results in the context of the Standard Model.

  9. Top quark mass measurements at the Tevatron

    SciTech Connect

    Youn, S. W.

    2014-03-01

    We present recent measurements of the mass of the top quark performed at the Tevatron $p\\bar{p}$ collider at a center-of-mass energy of 1.96 TeV. These measurements use the full Run II data samples corresponding to an integrated luminosity of up to 9.3 fb$^{-1}$. We also report the first world combination of the measurements from the Large Hadron Collider and Tevatron experiments resulting in a top mass of 173.34 {\\pm} 0.76 GeV with a relative precision of 0.44\\%.

  10. TOP500 Supercomputers for November 2003

    SciTech Connect

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2003-11-16

    22nd Edition of TOP500 List of World s Fastest Supercomputers Released MANNHEIM, Germany; KNOXVILLE, Tenn.; BERKELEY, Calif. In what has become a much-anticipated event in the world of high-performance computing, the 22nd edition of the TOP500 list of the worlds fastest supercomputers was released today (November 16, 2003). The Earth Simulator supercomputer retains the number one position with its Linpack benchmark performance of 35.86 Tflop/s (''teraflops'' or trillions of calculations per second). It was built by NEC and installed last year at the Earth Simulator Center in Yokohama, Japan.

  11. Studies of top quark properties and search for electroweak single top quark production at the Tevatron

    SciTech Connect

    Datta, Mousumi; /Fermilab

    2007-10-01

    The top quark was discovered in 1995 by the CDF and D0 experiments at the Fermilab Tevatron during the Run I operation. Since the start of the Tevatron Run II in 2001, both experiments have collected {approx}2 fb{sup -1} data samples, which are over twenty times larger than that used in the Run 1 discovery. This larger data sample allows more precise studies of top-quark properties; differences between observed top-quark properties and the Standard Model (SM) prediction may give hints to possible physics beyond the SM. Here we present the latest results on the measurements of top-quark properties and the search for electroweak (EW) single top quark production from the CDF and D0 collaborations. The integrated luminosity used for the measurements corresponds to about 1 fb{sup -1}.

  12. Determination of the top-quark mass from hadro-production of single top-quarks

    NASA Astrophysics Data System (ADS)

    Alekhin, S.; Moch, S.; Thier, S.

    2016-12-01

    We present a new determination of the top-quark mass mt based on the experimental data from the Tevatron and the LHC for single-top hadro-production. We use the inclusive cross sections of s- and t-channel top-quark production to extract mt and to minimize the dependence on the strong coupling constant and the gluon distribution in the proton compared to the hadro-production of top-quark pairs. As part of our analysis we compute the next-to-next-to-leading order approximation for the s-channel cross section in perturbative QCD based on the known soft-gluon corrections and implement it in the program HATHOR for the numerical evaluation of the hadronic cross section. Results for the top-quark mass are reported in the MS ‾ and in the on-shell renormalization scheme.

  13. Thermal analysis of double-layer metal films during femtosecond laser heating

    NASA Astrophysics Data System (ADS)

    Chen, A. M.; Jiang, Y. F.; Sui, L. Z.; Liu, H.; Jin, M. X.; Ding, D. J.

    2011-05-01

    In this paper, the primary interest is the heat effect of the bottom-layer metal on the temperature distribution of the top-layer metal in a double-layer metal structure during femtosecond laser irradiation. The evolution of the surface electron and lattice temperature depends a lot on the thermal parameters of the substrate. The damage threshold can be increased by using a substrate material with high electron-lattice coupling factor. Next, we choose chrome as the bottom-layer material. The results of modeling show that the surface lattice temperature of top-layer gold can be reduced remarkably. For a fixed entire thickness of the double-layer film, there is an optimal proportion of top and bottom layers for which the damage threshold is the highest possible. Also, for increasing the damage threshold, a substrate with higher melting temperature should be chosen.

  14. Addressing Raman features of individual layers in isotopically labeled Bernal stacked bilayer graphene

    NASA Astrophysics Data System (ADS)

    Costa, Sara D.; Weis, Johan Ek; Frank, Otakar; Fridrichová, Michaela; Kalbac, Martin

    2016-06-01

    In this report important Raman modes for the evaluation of strain in graphene (the 2D and 2D‧) are analyzed. The isotope labeling is used to disentangle contribution of individual graphene layers of graphene bilayer to the studied Raman modes. It is shown that for Bernal-stacked bilayers, the 2D and the 2D‧ Raman modes have three distinct components that can be assigned to processes originating solely from the top graphene layer, bottom graphene layer, and from a combination of processes originating both from the top and bottom layers. The reported results thus enable addressing the properties of individual graphene layers in graphene bilayer by Raman spectroscopy.

  15. Cloud layer thicknesses from a combination of surface and upper-air observations

    NASA Technical Reports Server (NTRS)

    Poore, Kirk D.; Wang, Junhong; Rossow, William B.

    1995-01-01

    Cloud layer thicknesses are derived from base and top altitudes by combining 14 years (1975-1988) of surface and upper-air observations at 63 sites in the Northern Hemisphere. Rawinsonde observations are employed to determine the locations of cloud-layer top and base by testing for dewpoint temperature depressions below some threshold value. Surface observations serve as quality checks on the rawinsonde-determined cloud properties and provide cloud amount and cloud-type information. The dataset provides layer-cloud amount, cloud type, high, middle, or low height classes, cloud-top heights, base heights and layer thicknesses, covering a range of latitudes from 0 deg to 80 deg N. All data comes from land sites: 34 are located in continental interiors, 14 are near coasts, and 15 are on islands. The uncertainties in the derived cloud properties are discussed. For clouds classified by low-, mid-, and high-top altitudes, there are strong latitudinal and seasonal variations in the layer thickness only for high clouds. High-cloud layer thickness increases with latitude and exhibits different seasonal variations in different latitude zones: in summer, high-cloud layer thickness is a maximum in the Tropics but a minimum at high latitudes. For clouds classified into three types by base altitude or into six standard morphological types, latitudinal and seasonal variations in layer thickness are very small. The thickness of the clear surface layer decreases with latitude and reaches a summer minimum in the Tropics and summer maximum at higher latitudes over land, but does not vary much over the ocean. Tropical clouds occur in three base-altitude groups and the layer thickness of each group increases linearly with top altitude. Extratropical clouds exhibit two groups, one with layer thickness proportional to their cloud-top altitude and one with small (less than or equal to 1000 m) layer thickness independent of cloud-top altitude.

  16. 5 CFR 1312.27 - Top secret control.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Top secret control. 1312.27 Section 1312... Classified Information § 1312.27 Top secret control. The EOP Security Officer serves as the Top Secret... Top Secret material. The ATSCOs will be responsible for the accountability and custodianship of...

  17. 49 CFR 178.812 - Top lift test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... (b) Special preparation for the top lift test. (1) Metal, rigid plastic, and composite IBC design... 49 Transportation 2 2010-10-01 2010-10-01 false Top lift test. 178.812 Section 178.812... Testing of IBCs § 178.812 Top lift test. (a) General. The top lift test must be conducted for...

  18. 49 CFR 178.975 - Top lift test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Large Packagings, from the side. (b) Special preparation for the top lift test. (1) Metal and rigid... 49 Transportation 2 2010-10-01 2010-10-01 false Top lift test. 178.975 Section 178.975... Testing of Large Packagings § 178.975 Top lift test. (a) General. The top lift test must be conducted...

  19. 5 CFR 1312.27 - Top secret control.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 3 2011-01-01 2011-01-01 false Top secret control. 1312.27 Section 1312... Classified Information § 1312.27 Top secret control. The EOP Security Officer serves as the Top Secret... Top Secret material. The ATSCOs will be responsible for the accountability and custodianship of...

  20. 49 CFR 178.812 - Top lift test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Top lift test. 178.812 Section 178.812... Top lift test. (a) General. The top lift test must be conducted for the qualification of all IBC design types designed to be lifted from the top or, for flexible IBCs, from the side. (b)...

  1. 49 CFR 178.975 - Top lift test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Top lift test. 178.975 Section 178.975... Packagings § 178.975 Top lift test. (a) General. The top lift test must be conducted for the qualification of all of Large Packagings design types to be lifted from the top or, for flexible Large Packagings,...

  2. 5 CFR 1312.27 - Top secret control.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 3 2013-01-01 2013-01-01 false Top secret control. 1312.27 Section 1312... Classified Information § 1312.27 Top secret control. The EOP Security Officer serves as the Top Secret... Top Secret material. The ATSCOs will be responsible for the accountability and custodianship of...

  3. 5 CFR 1312.27 - Top secret control.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 3 2012-01-01 2012-01-01 false Top secret control. 1312.27 Section 1312... Classified Information § 1312.27 Top secret control. The EOP Security Officer serves as the Top Secret... Top Secret material. The ATSCOs will be responsible for the accountability and custodianship of...

  4. 5 CFR 1312.27 - Top secret control.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 3 2014-01-01 2014-01-01 false Top secret control. 1312.27 Section 1312... Classified Information § 1312.27 Top secret control. The EOP Security Officer serves as the Top Secret... Top Secret material. The ATSCOs will be responsible for the accountability and custodianship of...

  5. 14. TIP TOP MINE. TAILINGS LOCATED DIRECTLY WEST FROM TIP ...

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

    14. TIP TOP MINE. TAILINGS LOCATED DIRECTLY WEST FROM TIP TOP HOUSE. ID-31-C-12 WOODEN STRUCTURE IS VISIBLE IN TOP LEFT. CABLES VISIBLE LEFT AND CENTER OF TAILINGS. HOUSE IS JUST OVER APEX OF TAILINGS. CAMERA POINTED EAST. - Florida Mountain Mining Sites, Tip Top Mine, West face Florida Mountain, approximately 150 feet below summit, Silver City, Owyhee County, ID

  6. 49 CFR 178.812 - Top lift test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... preparation for the top lift test. (1) Metal, rigid plastic, and composite IBC design types must be loaded to... 49 Transportation 3 2013-10-01 2013-10-01 false Top lift test. 178.812 Section 178.812... Top lift test. (a) General. The top lift test must be conducted for the qualification of all...

  7. Periodically porous top electrodes on vertical nanowire arrays for highly sensitive gas detection.

    PubMed

    In, Hyun Jin; Field, Christopher R; Pehrsson, Pehr E

    2011-09-02

    Nanowires of various materials and configurations have been shown to be highly effective in the detection of chemical and biological species. In this paper, we report a novel, nanosphere-enabled approach to fabricating highly sensitive gas sensors based on ordered arrays of vertically aligned silicon nanowires topped with a periodically porous top electrode. The vertical array configuration helps to greatly increase the sensitivity of the sensor while the pores in the top electrode layer significantly improve sensing response times by allowing analyte gases to pass through freely. Herein, we show highly sensitive detection to both nitrogen dioxide (NO(2)) and ammonia (NH(3)) in humidified air. NO(2) detection down to 10 parts per billion (ppb) is demonstrated and an order-of-magnitude improvement in sensor response time is shown in the detection of NH(3).

  8. Functional metal-insulator-metal top contacts for Si-based color photodetectors

    NASA Astrophysics Data System (ADS)

    Butun, Serkan; Aydin, Koray

    2016-12-01

    Here, we report on Si-based color photodetectors using monolithically integrated metal-insulator-metal Fabry-Perot cavity top contacts. Contacts were formed by depositing Ag/SiO2/Ag layers with different oxide thicknesses for each color. This allowed controlling the transmission band position and width while maintaining the high conductivity. We have obtained over 55% external quantum efficiency for different colors both numerically and experimentally. The FWHM was less than 50 nm and the rejection ratio was an order of magnitude for each color. The total transmission through these top contacts exceeded that of dye filters used in conventional color CCDs and CMOS imaging arrays. In addition, these contacts performed similarly to recently proposed plasmonic hole array filters without the necessity of complicated fabrication steps like FIB milling and e-beam lithography. This type of top contacts can serve as a cheap alternative to dye filters used in contemporary devices without making the fabrication complicated.

  9. Solution-processed transparent blue organic light-emitting diodes with graphene as the top cathode

    PubMed Central

    Chang, Jung-Hung; Lin, Wei-Hsiang; Wang, Po-Chuan; Taur, Jieh-I; Ku, Ting-An; Chen, Wei-Ting; Yan, Shiang-Jiuan; Wu, Chih-I

    2015-01-01

    Graphene thin films have great potential to function as transparent electrodes in organic electronic devices, due to their excellent conductivity and high transparency. Recently, organic light-emitting diodes (OLEDs)have been successfully demonstrated to possess high luminous efficiencies with p-doped graphene anodes. However, reliable methods to fabricate n-doped graphene cathodes have been lacking, which would limit the application of graphene in flexible electronics. In this paper, we demonstrate fully solution-processed OLEDs with n-type doped multilayer graphene as the top electrode. The work function and sheet resistance of graphene are modified by an aqueous process which can also transfer graphene on organic devices as the top electrodes. With n-doped graphene layers used as the top cathode, all-solution processed transparent OLEDs can be fabricated without any vacuum process. PMID:25892370

  10. Light conversion efficiency of top-emitting organic light-emitting diode structure.

    PubMed

    Lee, Hyeongi; Won, Taeyoung

    2014-11-01

    Top-emitting organic light-emitting diodes (OLEDs) with a microcavity structure are presented in this paper. We performed a finite element (FE) analysis of a trilayer OLED that was inserted between the reflective layer and the semi-reflective layer of a device. We carried out an optical analysis of this OLED device and calculated the optimal width between the reflective layer and the semi-reflective layer to consider the microcavity effect. Our simulation revealed that the thickness of each layer can affect the recombination rate at the emission layer. We used five OLED devices. Device A is a reference device with a 42.5 nm hole transport layer (HTL), a 15 nm emission layer (EML) and a 45 nm electron transport layer (ETL). We varied the thickness of the HTL of Device A to 20 nm and 65 nm, and designated these devices as Device B and Device C, respectively. We also varied the thickness of the ETL of Device A to 20 nm and 65 nm, and designated these devices as Device D and Device E, respectively. As the thickness of the HTL and the ETL are decreased, a higher recombination rate is achieved. However, the highest recombination rate does not necessarily correspond to the highest external quantum efficiency (EQE) owing to the resonance effect. Our simulation revealed that the overall thickness of the device seems to be a more significant factor owing to the path of light.

  11. Top-Ten IT Issues, 2010

    ERIC Educational Resources Information Center

    Ingerman, Bret L.; Yang, Catherine

    2010-01-01

    The eleventh annual EDUCAUSE Current Issues Survey shows some very familiar themes among the top-ten IT issues of strategic importance to technology leaders in higher education. Indeed, all ten of the issues from the 2009 survey are back, albeit in a slightly different order. In addition, Strategic Planning returns as an issue of renewed…

  12. A Top Physicist Turns to Teaching

    ERIC Educational Resources Information Center

    Bollag, Burton

    2007-01-01

    This article describes how a top physicist took charge of reforming undergraduate science education at the University of British Columbia. Carl E. Wieman, the 2001 Nobel Prize winner in Physics, gave up his research career to devote himself to improving the way college science is taught. Wieman is heading up a $10.2 million science education…

  13. Top-Ten IT Issues, 2012

    ERIC Educational Resources Information Center

    Grajek, Susan

    2012-01-01

    In 2011, "EDUCAUSE" appointed a research panel of IT leaders from nineteen representative member institutions to both identify and prioritize the top IT issues facing their institutions. In two focus group sessions in September and October 2011, the panel members were asked the question: "What is the single-biggest IT-related issue currently…

  14. Green Power Partnership Top 30 College & University

    EPA Pesticide Factsheets

    The U.S. EPA's Green Power Partnership is a voluntary program designed to reduce the environmental impact of electricity generation by promoting renewable energy. The Top 30 College & University list details the largest higher ed green power users in GPP.

  15. FY 2003 Top 200 Users Survey Report

    DTIC Science & Technology

    2003-08-01

    rating of 90 percent. This may be because we have been unable to print brochures and announcements. Comparative Analysis on Effectiveness of Corporate ... Communication FY 2001 Top 200 Users Survey Strongly Agree or Agree Strongly Disagree or Disagree No Opinion New Product/ Service 92 2 6 Product

  16. What Top Management Expects from the Communicator.

    ERIC Educational Resources Information Center

    Fegley, Robert L.

    Top corporate management requires communications departments that maintain credibility with the public by developing the following qualities: integrity established through consistent and honest messages; accuracy based on solid research; authority derived from an understanding of the subject and from drawing on appropriate expertise; a…

  17. Top-Ten IT Issues: 2009

    ERIC Educational Resources Information Center

    Agee, Anne Scrivener; Yang, Catherine

    2009-01-01

    This article presents the top-ten IT-related issues in terms of strategic importance to the institution, as revealed by the tenth annual EDUCAUSE Current Issues Survey. These IT-related issues include: (1) Funding IT; (2) Administrative/ERP Information Systems; (3) Security; (4) Infrastructure/Cyberinfrastructure; (5) Teaching and Learning with…

  18. America's Star Libraries: Top-Rated Libraries

    ERIC Educational Resources Information Center

    Lance, Keith Curry; Lyons, Ray

    2009-01-01

    "Library Journal"'s national rating of public libraries, the "LJ" Index of Public Library Service 2009, Round 2, identifies 258 "star" libraries. Created by Keith Curry Lance and Ray Lyons and based on 2007 data from the IMLS, it rates 7,268 public libraries. The top libraries in each group get five, four, or three stars. All included libraries,…

  19. Race to Top Round Two Heating Up

    ERIC Educational Resources Information Center

    McNeil, Michele

    2010-01-01

    With the second-round deadline for federal Race to the Top Fund grants less than six weeks away, states are rushing to raise the stakes on their education reform plans as they fight over the remaining $3.4 billion in prize money. But in doing so, states from Massachusetts to Colorado are tangling with their teachers' unions as they test how far…

  20. W-Z-top-quark bags

    SciTech Connect

    Crichigno, Marcos P.; Shuryak, Edward; Flambaum, Victor V.; Kuchiev, Michael Yu.

    2010-10-01

    We discuss a new family of multiquanta-bound states in the standard model which exist due to the mutual Higgs-based attraction of the heaviest members of the standard model, namely, gauge quanta W, Z, and (anti)top quarks, t, t. We use a self-consistent mean-field approximation, up to a rather large particle number N. In this paper we do not focus on weakly bound, nonrelativistic bound states, but rather on 'bags' in which the Higgs vacuum expectation value is significantly modified or depleted. The minimal number N above which such states appear strongly depends on the ratio of the Higgs mass to the masses of W, Z, t, t: For a light Higgs mass, m{sub H{approx}}50 GeV, bound states start from N{approx}O(10), but for a ''realistic'' Higgs mass, m{sub H{approx}}100 GeV, one finds metastable/bound W, Z bags only for N{approx}O(1000). We also found that in the latter case pure top bags disappear for all N, although top quarks can still be well bound to the W bags. Anticipating the cosmological applications (discussed in the following Article [Phys. Rev. D 82, 073019]) of these bags as 'doorway states' for baryosynthesis, we also consider here the existence of such metastable bags at finite temperatures, when standard-model parameters such as Higgs, gauge, and top masses are significantly modified.

  1. Topping pressure for gas-storage cylinders

    NASA Technical Reports Server (NTRS)

    Haben, R. L.

    1979-01-01

    With charts derived from gas-storage system model, required topping pressure can be determined from initial cylinder pressure and temperature of gas entering cylinder. Charts are available for hydrogen and oxygen and can be developed for other important industrial gases as well.

  2. States Press Race to Top Blueprints

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2010-01-01

    States are pushing ahead with efforts to make sweeping changes to education policy through the Race to the Top program, despite some of them having seen individual schools and districts back out of the process because of concerns over the time and money required to make those plans a reality. The Obama administration has envisioned Race to the…

  3. The Top 10 Issues Impacting College Administrators.

    ERIC Educational Resources Information Center

    Kennedy, Mike

    2001-01-01

    Discusses the top challenges commonly confronted nationwide by college and universities, and similar facilities and businesses. Challenges include construction and repair, funding, housing, auxiliary services, maintenance and operations, marketing and recruiting, security and safety, staff training and retention, and technology. (GR)

  4. Race to Top Districts "Personalize" Plans

    ERIC Educational Resources Information Center

    McNeil, Michele

    2013-01-01

    The 16 Race to the Top district winners, pushed by $400 million in federal grants that put a premium on personalized learning, are embarking on vastly different makeovers of the classroom experience--from districtwide approaches to a narrower blueprint focused on middle school math. Despite the divergent approaches, a review of the winning…

  5. Top Four Trends in Student Information Systems

    ERIC Educational Resources Information Center

    Weathers, Robert

    2013-01-01

    The modern student information systems (SIS) is a powerful administrative tool with robust functionality. As such, it is essential that school and district administrators consider the top trends in modern student information systems before going forward with system upgrades or new purchases. These trends, described herein, are: (1) Support for…

  6. Electroweak symmetry breaking: Top quard condensates

    SciTech Connect

    Bardeen, W.A.

    1990-12-01

    The fundamental mechanisms for the dynamical breaking of the electroweak gauge symmetries remain a mystery. This paper examines the possible role of heavy fermions, particularly the top quark, in generating the observed electroweak symmetry breaking, the masses of the W and Z bosons and the masses of all observed quarks and leptons. 27 refs., 10 figs., 4 tabs.

  7. Hurdles Ahead in "Race to Top"

    ERIC Educational Resources Information Center

    McNeil, Michele

    2009-01-01

    As states scramble to spend and report on millions of dollars of education stimulus funds already flowing their way, they face another daunting task if they want a shot at even more money: navigating the complex application process for $4 billion from the Race to the Top Fund. Merely filling out the award application will take each state 642…

  8. More Top Students Answer the Ministry's Call

    ERIC Educational Resources Information Center

    Supiano, Beckie

    2008-01-01

    In an effort to help reverse a decades-long decline in the number of top students entering seminaries, the Lilly Endowment invited colleges to compete for grants to be used for three related purposes: (1) to help students explore the relationship between faith and work; (2) to encourage talented students to consider entering Christian ministry;…

  9. Race to Top Enters Home Stretch

    ERIC Educational Resources Information Center

    McNeil, Michele; Maxwell, Lesli A.

    2010-01-01

    When 16 finalists come to Washington next week to make their final pitches in the $4 billion Race to the Top competition, most can expect to go home empty-handed. U.S. Secretary of Education Arne Duncan, in announcing the finalists last week, said that no more than $2 billion will be divided among "very few winners" when the awards are…

  10. Search for top quark at CDF

    SciTech Connect

    Not Available

    1994-11-01

    There is a vast theoretical and experimental support for idea that op quark as a weak isospin partner to b-quark should exist. Production cross section is steeply falling function of top quark mass. Therefore realistically at present only Tevatron p[anti p] collider at FNAL, with total energy 1.8 TeV in CMS system, still has a chance of top quark discovery. Dominant production mechanism for top quarks at Tevatron is pair production of t[anti t]. With almost 100% probability t ([anti t]) decays in mode t [yields] W[sup +]b. Distinct features of this decay provide very good signatures of top quark production which helps to reduce otherwise very high level of background. Based on simple combinatorial arguments one can show that W should decay in 1/9 cases into W [yields] l + [nu] where l stands for lepton (e,[mu],[tau]). Very clean signature represents case when both W's from t and [anti t] decay into e ([mu]) + [nu]. In this case experimental observation will be two isolated leptons characterized by large transverse momentum, large missing transverse energy E[sub T] and 2 b quark jets. Jets originated from b quarks can be quite frequently recognized by presence of secondary vertices associated with jets. Another feature of b-jets which can be used for their identification is frequent association of so called soft leptons with jets. Two experimental setups CDF and D0 are able to take advantage of Tevatron for top quark discovery. Recently CDF collaboration presented evidence for direct observation of t[anti t] production in 19.3 pb[sup [minus]1] of p[anti p] collisions at [radical](s) = 1.8TeV. Very brief account of these results is presented here.

  11. 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

  12. Recent Results of Top Quark Physics from the Tevatron

    SciTech Connect

    Peters, R. Y.

    2015-07-09

    Twenty years after its discovery in 1995 by the CDF and D0 collaborations at the Tevatron proton-antiproton collider at Fermilab, the top quark still undergoes intensive studies at the Tevatron and the LHC at CERN. In this article, recent top quark physics results from CDF and D0 are reported. In particular, measurements of single top quark and double top quark production, the $t\\bar{t}$ forward-backward asymmetry and the top quark mass are discussed.

  13. Top quark physics results from CDF and D-Zero

    SciTech Connect

    Gerdes, D.

    1996-10-01

    I summarize recent top quark physics results from the Fermilab Tevatron experiments. Since the observation of the top quark by CDF and D{null} in 1995, the experimental focus has shifted to a detailed study of the top quark`s properties. This article describes recent measurements of the top quark production cross section, mass, kinematic properties, branching ratios, V{sub {ital tb}}, and the {ital W} polarization in top decays.

  14. 5. VIEW OF TIP TOP WITH FAR RIGHT SADDLE PROVIDING ...

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

    5. VIEW OF TIP TOP WITH FAR RIGHT SADDLE PROVIDING ORIENTATION FOR THE GENERAL DIRECTION TO NOTTINGHAM. CAMERA POINTED SOUTH-SOUTHWEST. NORTH SIDE OF TIP TOP BUILDING IS VISIBLE. (RUN STRAIGHT EDGE FROM LOWER LEFT CORNER TO TOP CENTER OF PRINT; TIP TOP LOCATED LIGHT AREA) ONTARIO IS LOCATED BELOW AND RIGHT OF TIP TOP. - Florida Mountain Mining Sites, Silver City, Owyhee County, ID

  15. Looking behind the scenes: Raman spectroscopy of top-gated epitaxial graphene through the substrate

    NASA Astrophysics Data System (ADS)

    Fromm, F.; Wehrfritz, P.; Hundhausen, M.; Seyller, Th

    2013-11-01

    Raman spectroscopy is frequently used to study the properties of epitaxial graphene grown on silicon carbide (SiC). In this work, we present a confocal micro-Raman study of epitaxial graphene on SiC(0001) in top-down geometry, i.e. in a geometry where both the primary laser light beam as well as the back-scattered light is guided through the SiC substrate. Compared to the conventional top-up configuration, in which confocal micro-Raman spectra are measured from the air side, we observe a significant intensity enhancement in top-down configuration, indicating that most of the Raman-scattered light is emitted into the SiC substrate. The intensity enhancement is explained in terms of dipole radiation at a dielectric surface. The new technique opens the possibility to probe graphene layers in devices where the graphene layer is covered by non-transparent materials. We demonstrate this by measuring gate-modulated Raman spectra of a top-gated epitaxial graphene field effect device. Moreover, we show that these measurements enable us to disentangle the effects of strain and charge on the positions of the prominent Raman lines in epitaxial graphene on SiC.

  16. Top-down heating for low substrate temperature synthesis of carbon nanotubes.

    PubMed

    Chen, G Y; Stolojan, V; Silva, S R P

    2010-06-01

    A top-down heating method to allow for low-temperature large area synthesis of carbon nanotubes using plasma-enhanced chemical vapour deposition is introduced in this paper. The approach utilizes top-down electromagnetic heating rather than conventional heating from a substrate heater under the electrode. A temperature gradient is created between the Ni catalyst surface and the substrate using a metal thermal control barrier layer, on which carbon nanotubes are grown as a function of the bias voltage, hydrocarbon concentrations and growth conditions. The heat during growth is provided by the plasma or energy coupling to the catalyst via top-down heating, which based on the coupled power density and the cooling of the substrate, in addition to the thermal 'barrier layer' properties will dictate the temperature of the growth surface. This unique approach of top-down heating with suitable cooling schemes, coupled with thermal barriers allows for the low substrate temperature synthesis of carbon nanotubes, scalable to large areas.

  17. Layer resolved capacitive probing of graphene bilayers

    NASA Astrophysics Data System (ADS)

    Zibrov, Alexander; Parmentier, François; Li, Jia; Wang, Lei; Hunt, Benjamin; Dean, Cory; Hone, James; Taniguchi, Takashi; Watanabe, Kenji; Young, Andrea

    Compared to single layer graphene, graphene bilayers have an additional ``which-layer'' degree of freedom that can be controlled by an external electric field in a dual-gated device geometry. We describe capacitance measurements capable of directly probing this degree of freedom. By performing top gate, bottom gate, and penetration field capacitance measurements, we directly extract layer polarization of both Bernal and twisted bilayers. We will present measurements of hBN encapsulated bilayers at both zero and high magnetic field, focusing on the physics of the highly degenerate zero-energy Landau level in the high magnetic field limit where spin, valley, and layer degeneracy are all lifted by electronic interactions.

  18. A submicrometer lifted diffused-layer MOSFET

    NASA Astrophysics Data System (ADS)

    Inokawa, Hiroshi; Kobayashi, Toshio; Kiuchi, Kazuhide

    1987-03-01

    A new lifted diffused-layer (LID) MOSFET has been devised and fabricated, where the major portions of the source/drain (S/D) diffused layers are placed on top of the field insulator to reduce S/D parasitic capacitances. The primary feature of this MOSFET is that the structure and processing are especially developed for submicrometer gate lengths. The fabricated LID MOSFET with a 0.5-micron gate length and a 10-nm gate oxide thickness showed good electrical characteristics, such as a maximum transconductance of 115 mS/mm and an inverter delay time of 59 ps/stage.

  19. Interrogating the superconductor Ca10(Pt4As8)(Fe2−xPtxAs2)5 Layer-by-layer

    PubMed Central

    Kim, Jisun; Nam, Hyoungdo; Li, Guorong; Karki, A. B.; Wang, Zhen; Zhu, Yimei; Shih, Chih-Kang; Zhang, Jiandi; Jin, Rongying; Plummer, E. W.

    2016-01-01

    Ever since the discovery of high-Tc superconductivity in layered cuprates, the roles that individual layers play have been debated, due to difficulty in layer-by-layer characterization. While there is similar challenge in many Fe-based layered superconductors, the newly-discovered Ca10(Pt4As8)(Fe2As2)5 provides opportunities to explore superconductivity layer by layer, because it contains both superconducting building blocks (Fe2As2 layers) and intermediate Pt4As8 layers. Cleaving a single crystal under ultra-high vacuum results in multiple terminations: an ordered Pt4As8 layer, two reconstructed Ca layers on the top of a Pt4As8 layer, and disordered Ca layer on the top of Fe2As2 layer. The electronic properties of individual layers are studied using scanning tunneling microscopy/spectroscopy (STM/S), which reveals different spectra for each surface. Remarkably superconducting coherence peaks are seen only on the ordered Ca/Pt4As8 layer. Our results indicate that an ordered structure with proper charge balance is required in order to preserve superconductivity. PMID:27739517

  20. Interrogating the superconductor Ca-10(Pt4As8)(Fe2-xPtxAs2)5 Layer-by-layer

    DOE PAGES

    Kim, Jisun; Zhu, Yimei; Nam, Hyoungdo; ...

    2016-10-14

    Ever since the discovery of high-Tc superconductivity in layered cuprates, the roles that individual layers play have been debated, due to difficulty in layer-by-layer characterization. While there is similar challenge in many Fe-based layered superconductors, the newly-discovered Ca10(Pt4As8)(Fe2As2)5 provides opportunities to explore superconductivity layer by layer, because it contains both superconducting building blocks (Fe2As2 layers) and intermediate Pt4As8 layers. Cleaving a single crystal under ultra-high vacuum results in multiple terminations: an ordered Pt4As8 layer, two reconstructed Ca layers on the top of a Pt4As8 layer, and disordered Ca layer on the top of Fe2As2 layer. The electronic properties of individualmore » layers are studied using scanning tunneling microscopy/spectroscopy (STM/S), which reveals different spectra for each surface. Remarkably superconducting coherence peaks are seen only on the ordered Ca/Pt4As8 layer. Our results indicate that an ordered structure with proper charge balance is required in order to preserve superconductivity.« less

  1. Interrogating the superconductor Ca10(Pt4As8)(Fe2-xPtxAs2)5 Layer-by-layer.

    PubMed

    Kim, Jisun; Nam, Hyoungdo; Li, Guorong; Karki, A B; Wang, Zhen; Zhu, Yimei; Shih, Chih-Kang; Zhang, Jiandi; Jin, Rongying; Plummer, E W

    2016-10-14

    Ever since the discovery of high-Tc superconductivity in layered cuprates, the roles that individual layers play have been debated, due to difficulty in layer-by-layer characterization. While there is similar challenge in many Fe-based layered superconductors, the newly-discovered Ca10(Pt4As8)(Fe2As2)5 provides opportunities to explore superconductivity layer by layer, because it contains both superconducting building blocks (Fe2As2 layers) and intermediate Pt4As8 layers. Cleaving a single crystal under ultra-high vacuum results in multiple terminations: an ordered Pt4As8 layer, two reconstructed Ca layers on the top of a Pt4As8 layer, and disordered Ca layer on the top of Fe2As2 layer. The electronic properties of individual layers are studied using scanning tunneling microscopy/spectroscopy (STM/S), which reveals different spectra for each surface. Remarkably superconducting coherence peaks are seen only on the ordered Ca/Pt4As8 layer. Our results indicate that an ordered structure with proper charge balance is required in order to preserve superconductivity.

  2. PREFACE: 5th International Workshop on Top Quark Physics (TOP2012)

    NASA Astrophysics Data System (ADS)

    Salamanna, G.; Boisvert, V.; Cerrito, L.; Khan, A.; Moretti, S.; Owen, M.; Schwanenberger, C.

    2013-07-01

    The 5th International Workshop on Top Quark Physics (TOP 2012) took place in Winchester, UK, from the 16-21 September. It gathered students as well as people active in the top quark sector and provided a framework to highlight the newest results and matters related to top quark physics. Discovered in 1995, the top quark is the sixth and heaviest of all quarks, and it is the only one with a lifetime short enough to be observed 'naked'. This makes it an important testing ground in the search for new physics. In fact, the fact of its mass being so much larger than the other quarks, hints at its special role in the Higgs mechanism. For the same reason, in many models of New Physics, new heavy resonances are expected to couple mostly with top quarks. Even if no new particles are observed, the direct correlation between its angular momentum and that of its detectable decay products allows us to probe indirectly New Physics in action when top quarks are created. In this edition of the TOP conference series, for the first time, the agenda was equally balanced between 'traditional' measurements and the now vast number of searches for physics BSM in the top quark sector, thanks mostly to the amount of data collected at the LHC in its Run I. New results were presented by both the Tevatron and the LHC collaborations: improved ttbar and single top cross-section measurements, refined techniques to measure the top quark mass and a large number of results on properties such as spin correlation and W boson polarization in top quark decays were shown. More technical discussions on the experimental issues, both from the detector and the simulation side also took place, drawing together experimentalists and theorists. Reviews of the latest results on ttbar asymmetry both from CDF and D0 and from ATLAS and CMS were shown, and theorists active in the field made some interesting points on this hot topic. Additionally, results on the search for fourth generation fermions and new

  3. Flexion bonding transfer of multilayered graphene as a top electrode in transparent organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Tae Lim, Jong; Lee, Hyunkoo; Cho, Hyunsu; Kwon, Byoung-Hwa; Sung Cho, Nam; Kuk Lee, Bong; Park, Jonghyurk; Kim, Jaesu; Han, Jun-Han; Yang, Jong-Heon; Yu, Byoung-Gon; Hwang, Chi-Sun; Chu Lim, Seong; Lee, Jeong-Ik

    2015-12-01

    Graphene has attracted considerable attention as a next-generation transparent conducting electrode, because of its high electrical conductivity and optical transparency. Various optoelectronic devices comprising graphene as a bottom electrode, such as organic light-emitting diodes (OLEDs), organic photovoltaics, quantum-dot LEDs, and light-emitting electrochemical cells, have recently been reported. However, performance of optoelectronic devices using graphene as top electrodes is limited, because the lamination process through which graphene is positioned as the top layer of these conventional OLEDs is a lack of control in the surface roughness, the gapless contact, and the flexion bonding between graphene and organic layer of the device. Here, a multilayered graphene (MLG) as a top electrode is successfully implanted, via dry bonding, onto the top organic layer of transparent OLED (TOLED) with flexion patterns. The performance of the TOLED with MLG electrode is comparable to that of a conventional TOLED with a semi-transparent thin-Ag top electrode, because the MLG electrode makes a contact with the TOLED with no residue. In addition, we successfully fabricate a large-size transparent segment panel using the developed MLG electrode. Therefore, we believe that the flexion bonding technology presented in this work is applicable to various optoelectronic devices.

  4. Flexion bonding transfer of multilayered graphene as a top electrode in transparent organic light-emitting diodes

    PubMed Central

    Tae Lim, Jong; Lee, Hyunkoo; Cho, Hyunsu; Kwon, Byoung-Hwa; Sung Cho, Nam; Kuk Lee, Bong; Park, Jonghyurk; Kim, Jaesu; Han, Jun-Han; Yang, Jong-Heon; Yu, Byoung-Gon; Hwang, Chi-Sun; Chu Lim, Seong; Lee, Jeong-Ik

    2015-01-01

    Graphene has attracted considerable attention as a next-generation transparent conducting electrode, because of its high electrical conductivity and optical transparency. Various optoelectronic devices comprising graphene as a bottom electrode, such as organic light-emitting diodes (OLEDs), organic photovoltaics, quantum-dot LEDs, and light-emitting electrochemical cells, have recently been reported. However, performance of optoelectronic devices using graphene as top electrodes is limited, because the lamination process through which graphene is positioned as the top layer of these conventional OLEDs is a lack of control in the surface roughness, the gapless contact, and the flexion bonding between graphene and organic layer of the device. Here, a multilayered graphene (MLG) as a top electrode is successfully implanted, via dry bonding, onto the top organic layer of transparent OLED (TOLED) with flexion patterns. The performance of the TOLED with MLG electrode is comparable to that of a conventional TOLED with a semi-transparent thin-Ag top electrode, because the MLG electrode makes a contact with the TOLED with no residue. In addition, we successfully fabricate a large-size transparent segment panel using the developed MLG electrode. Therefore, we believe that the flexion bonding technology presented in this work is applicable to various optoelectronic devices. PMID:26626439

  5. Post annealing effect on the electrical properties of top-gate SWNT network transistors.

    PubMed

    Kim, Un Jeong; Suh, D Y; Min, S C; Park, Wanjun

    2011-07-01

    High performance top-gate single walled carbon nanotube network transistors are fabricated with aluminum oxide (Al2O3) layer as a gate dielectric by atomic layer deposition. It exhibits large on/off ratio (>10(4)) due to selective growth of semiconducting tubes by the plasma enhanced chemical vapor deposition. I-V characteristics show p-type or n-type depending on the deposition temperature. We investigate the type dependent characteristics for the carrier polarities with the post annealing effect on the top-gate SWNT network transistors. The dramatic change in the polarity of the top-gate SWNT network transistors, from n-type to p-type due to conversion of I-V characteristics is observed by post-annealing at 350 degrees C for 30 minutes under vacuum. Our observation suggests that competition between electron transfer from the Al2O3 layers to the SWNT surface and electron capture by oxygen molecules adsorbed on the tube walls seems to be the key point for the V(th) change as a function of Al2O3 deposition temperature.

  6. TOP500 Supercomputers for June 2003

    SciTech Connect

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2003-06-23

    21st Edition of TOP500 List of World's Fastest Supercomputers Released MANNHEIM, Germany; KNOXVILLE, Tenn.;&BERKELEY, Calif. In what has become a much-anticipated event in the world of high-performance computing, the 21st edition of the TOP500 list of the world's fastest supercomputers was released today (June 23, 2003). The Earth Simulator supercomputer built by NEC and installed last year at the Earth Simulator Center in Yokohama, Japan, with its Linpack benchmark performance of 35.86 Tflop/s (teraflops or trillions of calculations per second), retains the number one position. The number 2 position is held by the re-measured ASCI Q system at Los Alamos National Laboratory. With 13.88 Tflop/s, it is the second system ever to exceed the 10 Tflop/smark. ASCIQ was built by Hewlett-Packard and is based on the AlphaServerSC computer system.

  7. The heavy top quark and supersymmetry

    SciTech Connect

    Hall, L.J. |

    1997-01-01

    Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the Standard Model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top quark; an extension of isospin provides a constrained framework for understanding the pattern of quark and lepton masses; and a grand unified extension of the Standard Model gauge group provides an elegant understanding of the gauge quantum numbers of the components of a generation. Experimental signatures for each of these additional symmetries are discussed.

  8. Top quark production measurements at ATLAS

    NASA Astrophysics Data System (ADS)

    Calkins, R.; Atlas Collaboration

    2012-09-01

    An overview of top quark production measurements using the ATLAS detector at the LHC is presented. Using 35 pb-1 of data, we measured the tt¯ cross-section in the lepton+jets channel to 13% precision and set limits on the cross-section for the all hadronic decay channel[1, 2]. The measurement in the dilepton channel was performed using 0.70 fb-1 of data and was combined with the lepton+jets channel result for our most precise tt¯ cross-section measurement of σpp→tt¯+X = 176±5 (stat)+13-10 (syst)±7 (lumi)[3,4]. Single top production was also measured in the t-channel using 0.70 fb-1 of data[5].

  9. The heavy top quark and supersymmetry

    SciTech Connect

    Hall, L.J. |

    1996-05-08

    Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the standard model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top quark; an extension of isospin provides a constrained framework for understanding the pattern of quark and lepton masses; and a grand unified extension of the standard model gauge group provides an elegant understanding of the gauge quantum numbers of the components of a generation. Experimental signatures for each of these additional symmetries are discussed.

  10. Entanglement entropy in top-down models

    NASA Astrophysics Data System (ADS)

    Jones, Peter A. R.; Taylor, Marika

    2016-08-01

    We explore holographic entanglement entropy in ten-dimensional supergravity solutions. It has been proposed that entanglement entropy can be computed in such top-down models using minimal surfaces which asymptotically wrap the compact part of the geometry. We show explicitly in a wide range of examples that the holographic entan-glement entropy thus computed agrees with the entanglement entropy computed using the Ryu-Takayanagi formula from the lower-dimensional Einstein metric obtained from reduc-tion over the compact space. Our examples include not only consistent truncations but also cases in which no consistent truncation exists and Kaluza-Klein holography is used to identify the lower-dimensional Einstein metric. We then give a general proof, based on the Lewkowycz-Maldacena approach, of the top-down entanglement entropy formula.

  11. Top-down visual search in Wimmelbild

    NASA Astrophysics Data System (ADS)

    Bergbauer, Julia; Tari, Sibel

    2013-03-01

    Wimmelbild which means "teeming figure picture" is a popular genre of visual puzzles. Abundant masses of small figures are brought together in complex arrangements to make one scene in a Wimmelbild. It is picture hunt game. We discuss what type of computations/processes could possibly underlie the solution of the discovery of figures that are hidden due to a distractive influence of the context. One thing for sure is that the processes are unlikely to be purely bottom-up. One possibility is to re-arrange parts and see what happens. As this idea is linked to creativity, there are abundant examples of unconventional part re-organization in modern art. A second possibility is to define what to look for. That is to formulate the search as a top-down process. We address top-down visual search in Wimmelbild with the help of diffuse distance and curvature coding fields.

  12. Top cross section measurement at CDF

    SciTech Connect

    Compostella, Gabriele; /INFN, CNAF /Padua U.

    2010-01-01

    This paper describes the latest measurements of the t{bar t} pair production cross section performed by the CDF Collaboration analyzing p{bar p} collisions at a center-of-mass energy of 1.96 TeV from Fermilab Tevatron, as presented at the XVIII International Workshop on Deep-Inelastic Scattering and Related Subjects. In order to test Standard Model predictions, several analysis methods are explored and all the top decay channels are considered, to better constrain the properties of the top quark and to search for possible sources of new physics affecting the pair production mechanism. Experimental results using an integrated luminosity up to 5.1 fb{sup -1} are presented.

  13. TOP500 Supercomputers for November 2002

    SciTech Connect

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2002-11-15

    20th Edition of TOP500 List of World's Fastest Supercomputers Released MANNHEIM, Germany; KNOXVILLE, Tenn.;&BERKELEY, Calif. In what has become a much-anticipated event in the world of high-performance computing, the 20th edition of the TOP500 list of the world's fastest supercomputers was released today (November 15, 2002). The Earth Simulator supercomputer installed earlier this year at the Earth Simulator Center in Yokohama, Japan, is with its Linpack benchmark performance of 35.86 Tflop/s (trillions of calculations per second) retains the number one position. The No.2 and No.3 positions are held by two new, identical ASCI Q systems at Los Alamos National Laboratory (7.73Tflop/s each). These systems are built by Hewlett-Packard and based on the Alpha Server SC computer system.

  14. Kodiak seamount not flat-topped.

    PubMed

    Hamilton, E L; von Huene, R E

    1966-12-09

    Earlier surveys in the Aleutian Trench southeast of Kodiak Island, Alaska, indicated that Kodiak Seamount had a flat top and was a tablemount or guyot. This seamount is of special significance because it has been supposed that its surface was eroded at the same time as those of a line of guyots to the southeast. If so, its present position in the axis of the Aleutian Trench indicates that the line of guyots was formed before the trench. A two-part survey in 1965 showed that Kodiak Seamount is not flat-topped, and should be eliminated from the category of guyots. Reflection profiling records indicate that the seamount was formed before the adjacent sediments were deposited, and that the small trough, or moat, on the south side is a depositional feature probably formed by a scouring effect or by the acceleration of turbidity currents around the base of the mount.

  15. Top quark kinematics and mass determination

    SciTech Connect

    Williams, H.H.

    1994-10-01

    An analysis is presented of 10 W + {ge} 3 jet events, each with evidence for the presence of a b quark, that were recently observed by the CDF collaboration. Seven of these events include a fourth jet and can be explicitly reconstructed as t{bar t} production. The best estimate of the top quark mass is M{sub t} = 174 {+-} 10{sub {minus}12}{sup +13} GeV/c{sup 2}. A study has also been performed to see if the kinematical properties of events with W + {ge} 3 jets gives evidence for top production. An excess of events with large jet energies, compared to that expected from direct production of W + {ge} 3 jets, is observed. A large fraction of these events also contain a b-quark and a fourth jet.

  16. Top quark and electroweak results from CDF

    SciTech Connect

    Sandra Leone

    2003-11-04

    In 2001 the Tevatron run II began, after a five year period of significant upgrade of the accelerator itself and of the experiments CDF and D0. After a detector commissioning run, the CDF experiment is now taking high quality data with all subsystems functional. We report in this talk the first preliminary CDF results on top quark and W/Z boson properties, based on run II data. The top quark, discovered in 1995 at the Tevatron, has proven to be a very interesting particle. Its properties allow to perform stringent tests of the Standard Model (SM) and to search for new physics through a deviation from SM predictions. We give here some expectations of what Tevatron run II will ultimately provide to our understanding of matter.

  17. Top physics at the Tevatron Collider

    SciTech Connect

    Margaroli, Fabrizio; /Purdue U.

    2007-10-01

    The top quark has been discovered in 1995 at the CDF and DO experiments located in the Tevatron ring at the Fermilab laboratory. After more than a decade the Tevatron collider, with its center-of-mass energy collisions of 1.96 TeV, is still the only machine capable of producing such exceptionally heavy particle. Here I present a selection of the most recent CDF and DO measurements performed analyzing {approx} 1 fb{sup -1} of integrated luminosity.

  18. Rare top quark decays in extended models

    SciTech Connect

    Gaitan, R.; Miranda, O. G.; Cabral-Rosetti, L. G.

    2006-09-25

    Flavor changing neutral currents (FCNC) decays t {yields} H0 + c, t {yields} Z + c, and H0 {yields} t + c-bar are discussed in the context of Alternative Left-Right symmetric Models (ALRM) with extra isosinglet heavy fermions where FCNC decays may take place at tree-level and are only suppressed by the mixing between ordinary top and charm quarks, which is poorly constraint by current experimental values. The non-manifest case is also briefly discussed.

  19. Braking, Wheeled Vehicles. Test Operations Procedure (TOP)

    DTIC Science & Technology

    2008-05-20

    are as follows: a. Micrometer calipers (inside, outside, and dial types). b. Surface finish gauges. c. Torque wrench. d. Brake shoe...is imminent. 11. Front Disc Brakes Procedure: Step 1: Visually inspect and measure rotors, calipers , and pads. Equipment needed...4. TITLE AND SUBTITLE Test Operations Procedure (TOP) 2-2-608 Braking , Wheeled Vehicles 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 5e

  20. Charm, beauty and top at HERA

    NASA Astrophysics Data System (ADS)

    Behnke, O.; Geiser, A.; Lisovyi, M.

    2015-09-01

    Results on open charm and beauty production and on the search for top production in high-energy electron-proton collisions at HERA are reviewed. This includes a discussion of relevant theoretical aspects, a summary of the available measurements and measurement techniques, and their impact on improved understanding of QCD and its parameters, such as parton density functions and charm- and beauty-quark masses. The impact of these results on measurements at the LHC and elsewhere is also addressed.

  1. Slow Pace for Race to Top Spending

    ERIC Educational Resources Information Center

    McNeil, Michele

    2012-01-01

    Almost two years into the federal Race to the Top program, states are spending their shares of the $4 billion prize at a snail's pace--a reflection of the challenges the 12 winners face as they try to get ambitious education improvement plans off the ground. Through the end of March, the 11 states and the District of Columbia had spent just 14…

  2. The myth of the top management team.

    PubMed

    Katzenbach, J R

    1997-01-01

    Companies all across the economic spectrum are making use of teams. They go by a variety of names and can be found at all levels. In fact, you are likely to find the group at the very top of an organization professing to be a team. But even in the best of companies, a so-called top team seldom functions as a real team. Real teams must follow a well-defined discipline to achieve their performance potential. And performance is the key issue--not the fostering of "team values" such as empowerment, sensitivity, or involvement. In recent years, the focus on performance was lost in many companies. Even today, CEOs and senior executives often see few gains in performance from their attempts to become more teamlike. Nevertheless, a team effort at the top can be essential to capturing the highest performance results possible--when the conditions are right. Good leadership requires differentiating between team and nonteam opportunities, and then acting accordingly. Three litmus tests must be passed for a team at the top to be effective. First, the team must shape collective work-products--these are tangible performance results that the group can achieve working together that surpass what the team members could have achieved working on their own. Second, the leadership role must shift, depending on the task at hand. And third, the team's members must be mutually accountable for the group's results. When these criteria can be met, senior executives should come together to achieve real team performance. When the criteria cannot be met, they should rely on the individual leadership skills that they have honed over the years.

  3. The Top 10 Lists of 2011

    ERIC Educational Resources Information Center

    American School & University, 2011

    2011-01-01

    This article presents lists of the top ten schools with most students, largest enrollment, and other categories for 2011 in the U.S. The school districts with most student for 2010-2011 are New York City with 1,043,886 followed by Los Angeles with 667,251, Chicago with 403,770 and down to the 10th spot Orange County (Fla.) with 175,986. The…

  4. Optical property measurement from layered biological media

    NASA Astrophysics Data System (ADS)

    Muller, Matthew R.

    1998-12-01

    concisely, and Ke becomes a tool in describing the layered optical properties. This approach is applied clinically to measure changes in the blood concentration and oxygenation measured in vivo from normals and patients with peripheral vascular disease. A significant finding from the modeling was to identify the functional relationship of Ke to the top and lower layer diffusion constants, and the top layer thickness. When applied to in vitro measurements from media containing homogeneous layers with known optical properties, this functional relationship predicted Ke within the 95% confidence interval of the measured Ke. For the in vivo measurements, changes in K e with exercise are consistent with expected exercise physiology. With the incorporation of the known optical absorbance of hemoglobin in the presence of oxygen, the SRPs provide a means to measure the oxygen saturation of a deep tissue layer from the surface light reflectance.

  5. Top-down facilitation of visual recognition

    PubMed Central

    Bar, M.; Kassam, K. S.; Ghuman, A. S.; Boshyan, J.; Schmid, A. M.; Dale, A. M.; Hämäläinen, M. S.; Marinkovic, K.; Schacter, D. L.; Rosen, B. R.; Halgren, E.

    2006-01-01

    Cortical analysis related to visual object recognition is traditionally thought to propagate serially along a bottom-up hierarchy of ventral areas. Recent proposals gradually promote the role of top-down processing in recognition, but how such facilitation is triggered remains a puzzle. We tested a specific model, proposing that low spatial frequencies facilitate visual object recognition by initiating top-down processes projected from orbitofrontal to visual cortex. The present study combined magnetoencephalography, which has superior temporal resolution, functional magnetic resonance imaging, and a behavioral task that yields successful recognition with stimulus repetitions. Object recognition elicited differential activity that developed in the left orbitofrontal cortex 50 ms earlier than it did in recognition-related areas in the temporal cortex. This early orbitofrontal activity was directly modulated by the presence of low spatial frequencies in the image. Taken together, the dynamics we revealed provide strong support for the proposal of how top-down facilitation of object recognition is initiated, and our observations are used to derive predictions for future research. PMID:16407167

  6. Dark decay of the top quark

    DOE PAGES

    Kong, Kyoungchul; Lee, Hye -Sung; Park, Myeonghun

    2014-04-01

    We suggest top quark decays as a venue to search for light dark force carriers. Top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6 σ deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t → b W + Z's. This is the same as the dominant topmore » quark decay (t → b W) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. In addition, we discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.« less

  7. TOP500 Sublist for November 2001

    SciTech Connect

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack J.; Simon,Horst D.

    2001-11-09

    18th Edition of TOP500 List of World's Fastest Supercomputers Released MANNHEIM, GERMANY; KNOXVILLE, TENN.; BERKELEY, CALIF. In what has become a much-anticipated event in the world of high-performance computing, the 18th edition of the TOP500 list of the world's fastest supercomputers was released today (November 9, 2001). The latest edition of the twice-yearly ranking finds IBM as the leader in the field, with 32 percent in terms of installed systems and 37 percent in terms of total performance of all the installed systems. In a surprise move Hewlett-Packard captured the second place with 30 percent of the systems. Most of these systems are smaller in size and as a consequence HP's share of installed performance is smaller with 15 percent. This is still enough for second place in this category. SGI, Cray and Sun follow in the number of TOP500 systems with 41 (8 percent), 39 (8 percent), and 31 (6 percent) respectively. In the category of installed performance Cray Inc. keeps the third position with 11 percent ahead of SGI (8 percent) and Compaq (8 percent).

  8. Tracking down hyper-boosted top quarks

    NASA Astrophysics Data System (ADS)

    Larkoski, Andrew J.; Maltoni, Fabio; Selvaggi, Michele

    2015-06-01

    The identification of hadronically decaying heavy states, such as vector bosons, the Higgs, or the top quark, produced with large transverse boosts has been and will continue to be a central focus of the jet physics program at the Large Hadron Collider (LHC). At a future hadron collider working at an order-of-magnitude larger energy than the LHC, these heavy states would be easily produced with transverse boosts of several TeV. At these energies, their decay products will be separated by angular scales comparable to individual calorimeter cells, making the current jet substructure identification techniques for hadronic decay modes not directly employable. In addition, at the high energy and luminosity projected at a future hadron collider, there will be numerous sources for contamination including initial- and final-state radiation, underlying event, or pile-up which must be mitigated. We propose a simple strategy to tag such "hyper-boosted" objects that defines jets with radii that scale inversely proportional to their transverse boost and combines the standard calorimetric information with charged track-based observables. By means of a fast detector simulation, we apply it to top quark identification and demonstrate that our method efficiently discriminates hadronically decaying top quarks from light QCD jets up to transverse boosts of 20 TeV. Our results open the way to tagging heavy objects with energies in the multi-TeV range at present and future hadron colliders.

  9. Tracking down hyper-boosted top quarks

    SciTech Connect

    Larkoski, Andrew J.; Maltoni, Fabio; Selvaggi, Michele

    2015-06-05

    The identification of hadronically decaying heavy states, such as vector bosons, the Higgs, or the top quark, produced with large transverse boosts has been and will continue to be a central focus of the jet physics program at the Large Hadron Collider (LHC). At a future hadron collider working at an order-of-magnitude larger energy than the LHC, these heavy states would be easily produced with transverse boosts of several TeV. At these energies, their decay products will be separated by angular scales comparable to individual calorimeter cells, making the current jet substructure identification techniques for hadronic decay modes not directly employable. In addition, at the high energy and luminosity projected at a future hadron collider, there will be numerous sources for contamination including initial- and final-state radiation, underlying event, or pile-up which must be mitigated. We propose a simple strategy to tag such "hyper-boosted" objects that defines jets with radii that scale inversely proportional to their transverse boost and combines the standard calorimetric information with charged track-based observables. By means of a fast detector simulation, we apply it to top quark identification and demonstrate that our method efficiently discriminates hadronically decaying top quarks from light QCD jets up to transverse boosts of 20 TeV. Lastly, our results open the way to tagging heavy objects with energies in the multi-TeV range at present and future hadron colliders.

  10. Observation of Single Top Quark Production

    SciTech Connect

    Gerber, Cecilia E.; /Illinois U., Chicago

    2009-09-01

    The author reports on the observation of electroweak production of single top quarks in p{bar p} collisions at {radical}s = 1.96 Tev using 2.3 fb{sup -1} of data collected with the D0 detector at the fermilab Tevatron Collider. Using events containing an isolated electron or muon, missing transverse energy, two, three or four jets, with one or two of them identified as originating from the fragmentation of a b quark, the measured cross section for the process p{bar p} {yields} tb + X, tqb + X is 3.94 {+-} 0.88 pb (for a top quark mass of 170 GeV). the probability to measure a cross section at this value or higher in the absence of signal is 2.5 x 10{sup -7}, corresponding to a 5.0 standard deviation significance. Using the same dataset, the measured cross sections for the t- and the s-channel processes when determined simultaneously with no assumption on their relative production rate are 3.14{sub -0.80}{sup +0.94} pb and 1.05 {+-} 0.81 pb respectively, consistent with standard model expectations. The measured t-channel cross section has a significance of 4.8 standard deviations, representing the first evidence for the production of an individual single top process to be detected.

  11. Tracking down hyper-boosted top quarks

    DOE PAGES

    Larkoski, Andrew J.; Maltoni, Fabio; Selvaggi, Michele

    2015-06-05

    The identification of hadronically decaying heavy states, such as vector bosons, the Higgs, or the top quark, produced with large transverse boosts has been and will continue to be a central focus of the jet physics program at the Large Hadron Collider (LHC). At a future hadron collider working at an order-of-magnitude larger energy than the LHC, these heavy states would be easily produced with transverse boosts of several TeV. At these energies, their decay products will be separated by angular scales comparable to individual calorimeter cells, making the current jet substructure identification techniques for hadronic decay modes not directlymore » employable. In addition, at the high energy and luminosity projected at a future hadron collider, there will be numerous sources for contamination including initial- and final-state radiation, underlying event, or pile-up which must be mitigated. We propose a simple strategy to tag such "hyper-boosted" objects that defines jets with radii that scale inversely proportional to their transverse boost and combines the standard calorimetric information with charged track-based observables. By means of a fast detector simulation, we apply it to top quark identification and demonstrate that our method efficiently discriminates hadronically decaying top quarks from light QCD jets up to transverse boosts of 20 TeV. Lastly, our results open the way to tagging heavy objects with energies in the multi-TeV range at present and future hadron colliders.« less

  12. Top quark physics at the Tevatron

    SciTech Connect

    Antonio Sidoti

    2004-03-17

    After the successful Run I of the Tevatron (1992-1996),with the top quark discovery, both CDF and D0 experiments were extensively upgraded to meet the challenges of the Tevatron Run II collider. The energy of p{bar p} collisions at the Tevatron was increased from {radical}s = 1.8 TeV to {radical}s = 1.96 TeV. t{bar t} production cross section is expected to increase by a factor of {approx} 30%. Major upgrades in the Tevatron accelerator chain will increase the Run II instantaneous luminosity: the goal is to achieve L = 5 - 20 x 10{sup 31} cm{sup 2}s{sup -1} while the highest luminosity reached up to now (September 2003) is 5.2 x 10{sup 31} cm{sup 2} s{sup -1}. In this paper we will present the top quark properties measured by both CDF and D0 with the first physics-quality data collected during the Run II (March 2002-January 2003). First we will review t{bar t} cross section measurements in the various decay channels; then top quark mass measurements will be presented.

  13. Development of cliff-top dunes in the Hengchun Peninsula of the southern Taiwan

    NASA Astrophysics Data System (ADS)

    Ho, Lih-Der; Wong, Yi-Chia; Lüthgens, Christopher; Chyi, Shyhjeng; Yen, Jiun-Yee

    2016-04-01

    Fung-Chuei-Sha cliff-top dune is located on a 60-meter-high cliff surface in the Hengchun Peninsula of Taiwan. It is still unclear that the history of the aeolian sediment deposition on the top of the cliff, and what factors may influence the evolution of the cliff-top dune. This study aims to investigate the evolutionary history of the Fung-Chuei-Sha cliff-top dune by analyzing the grain size, CaCO3 concentration and absolute dates of the dune sediment, and the land snail species found in the deposit.The results show three phases of aeolian sand accumulation in the Fung-Chuei-Sha cliff-top dune. 1. Phase I: aeolian sediment may accumulate in the bottom of the cliff between 2800 yr BP and 2100 yr BP. 2. Phase II: the cliff-top dune accumulated a 3.1-meter-thick sediment layer from 1500 yr BP to 1300 yr BP. In this phase, dune sediment deposited in a rate of 1.55 cm/yr. The paleoclimate proxy data from the nearby area indicate that the environment was cool and dry, and the Asian winter monsoon was strong during 1500-1300 yr BP. It blew the old coastal dune deposit at the bottom of the cliff up to the cliff top, and induced the C14 age reverse phenomenon. The aeolian deposition began to stabilize because of the wetter environment in the end of the Phase II. At the same time, the stable dune formed the silt and clay layer on the surface of the dune. A layer cemented by CaCO3 may indicate the position of the palaeo-groundwater table. 3. Phase III: the phase stared from 1500-1300 yr BP to the present. A 2.4-meter-thick eolian deposit was accumulated in a rate of 0.18 cm/yr during this phase. Four kinds of land snail shells, Cyclophorus formosensis, Hemiphaedusa similaris, Platyrhaphe swinhoei, Odontartemon heudei, which prefer to live in a relatively humid environment, were commonly observed in the dune deposit, indicating the environment was wet and consequently caused a slower aeolian deposition rate at this phase. Between 1000 yr BP and 500 yr BP, there was a

  14. Top laminated graphene electrode in a semitransparent polymer solar cell by simultaneous thermal annealing/releasing method.

    PubMed

    Lee, Yu-Ying; Tu, Kun-Hua; Yu, Chen-Chieh; Li, Shao-Sian; Hwang, Jeong-Yuan; Lin, Chih-Cheng; Chen, Kuei-Hsien; Chen, Li-Chyong; Chen, Hsuen-Li; Chen, Chun-Wei

    2011-08-23

    In this article, we demonstrate a semitransparent inverted-type polymer solar cell using a top laminated graphene electrode without damaging the underlying organic photoactive layer. The lamination process involves the simultaneous thermal releasing deposition of the graphene top electrode during thermal annealing of the photoactive layer. The resulting semitransparent polymer solar cell exhibits a promising power conversion efficiency of approximately 76% of that of the standard opaque device using an Ag metal electrode. The asymmetric photovoltaic performances of the semitransparent solar cell while illuminated from two respective sides were further analyzed using optical simulation and photocarrier recombination measurement. The devices consisting of the top laminated transparent graphene electrode enable the feasible roll-to-roll manufacturing of low-cost semitransparent polymer solar cells and can be utilized in new applications such as power-generated windows or multijunction or bifacial photovoltaic devices.

  15. Modeling of water absorption induced cracks in resin-based composite supported ceramic layer structures.

    PubMed

    Huang, Min; Thompson, V P; Rekow, E D; Soboyejo, W O

    2008-01-01

    Cracking patterns in the top ceramic layers of the modeled dental multilayers with polymer foundation are observed when they are immersed in water. This article developed a model to understand this cracking mechanism. When water diffuses into the polymer foundation of dental restorations, the foundation will expand; as a result, the stress will build up in the top ceramic layer because of the bending and stretching. A finite element model based on this mechanism is built to predict the stress build-up and the slow crack growth in the top ceramic layers during the water absorption. Our simulations show that the stress build-up by this mechanism is high enough to cause the cracking in the top ceramic layers and the cracking patterns predicted by our model are well consistent with those observed in experiments on glass/epoxy/polymer multilayers. The model is then used to discuss the life prediction of different dental ceramics.

  16. Coating of nanoporous membranes: atomic layer deposition versus sputtering.

    PubMed

    Grigoras, K; Airaksinen, V M; Franssila, S

    2009-06-01

    Nanoporous anodic alumina membranes and silicon samples with plasma etched nanopores have been coated with zinc oxide or gold layer using atomic layer deposition (ALD) or sputtering, respectively. In the case of ALD process, the precursor pulses were extended, compared with planar substrate coating. Thick (60 microm) anodic alumina membranes have been conformally coated with zinc oxide ALD layer. Metal sputtering technique was used just for opposite purpose--to minimize the penetration of gold into the pores during gold-coating of the top and bottom surfaces of the membrane. Scanning electron microscopy (SEM) has been used to investigate the layer thickness, uniformity and conformality inside the nanopores.

  17. Measurements of top quark properties at the Tevatron collider

    SciTech Connect

    Margaroli, Fabrizio

    2011-05-01

    The discovery of the top quark in 1995 opened a whole new sector of investigation of the Standard Model; today top quark physics remains a key priority of the Tevatron program. Some of the measurements of top quark properties, for example its mass, will be a long-standing legacy. The recent evidence of an anomalously large charge asymmetry in top quark events suggests that new physics could couple preferably with top quarks. I will summarize this long chapter of particle physics history and discuss the road the top quark is highlighting for the LHC program.

  18. Laminated metal composite formed from low flow stress layers and high flow stress layers using flow constraining elements and making same

    DOEpatents

    Syn, Chol K.; Lesuer, Donald R.

    1995-01-01

    A laminated metal composite of low flow stress layers and high flow stress layers is described which is formed using flow constraining elements, preferably in the shape of rings, individually placed around each of the low flow stress layers while pressure is applied to the stack to bond the layers of the composite together, to thereby restrain the flow of the low flow stress layers from the stack during the bonding. The laminated metal composite of the invention is made by the steps of forming a stack of alternate layers of low flow stress layers and high flow stress layers with each layer of low flow stress material surrounded by an individual flow constraining element, such as a ring, and then applying pressure to the top and bottom surfaces of the resulting stack to bond the dissimilar layers together, for example, by compression rolling the stack. In a preferred embodiment, the individual flow constraining elements surrounding the layers of low flow stress material are formed of a material which may either be the same material as the material comprising the high flow stress layers, or have similar flow stress characteristics to the material comprising the high flow stress layers. Additional sacrificial layers may be added to the top and bottom of the stack to avoid damage to the stack during the bonding step; and these additional layers may then be removed after the bonding step.

  19. Laminated metal composite formed from low flow stress layers and high flow stress layers using flow constraining elements and making same

    DOEpatents

    Syn, C.K.; Lesuer, D.R.

    1995-07-04

    A laminated metal composite of low flow stress layers and high flow stress layers is described which is formed using flow constraining elements, preferably in the shape of rings, individually placed around each of the low flow stress layers while pressure is applied to the stack to bond the layers of the composite together, to thereby restrain the flow of the low flow stress layers from the stack during the bonding. The laminated metal composite of the invention is made by the steps of forming a stack of alternate layers of low flow stress layers and high flow stress layers with each layer of low flow stress material surrounded by an individual flow constraining element, such as a ring, and then applying pressure to the top and bottom surfaces of the resulting stack to bond the dissimilar layers together, for example, by compression rolling the stack. In a preferred embodiment, the individual flow constraining elements surrounding the layers of low flow stress material are formed of a material which may either be the same material as the material comprising the high flow stress layers, or have similar flow stress characteristics to the material comprising the high flow stress layers. Additional sacrificial layers may be added to the top and bottom of the stack to avoid damage to the stack during the bonding step; and these additional layers may then be removed after the bonding step. 5 figs.

  20. Snow Model for the F-Layer

    NASA Astrophysics Data System (ADS)

    Lasbleis, M.; Hernlund, J. W.; Labrosse, S.

    2015-12-01

    Seismic observations of the Earth's core reveal a complex structure: radial and lateral heterogeneities in seismic anisotropy and attenuation in the solid inner core, but also discrepancies between observed P-wave velocity and homogeneous PREM model in the deep liquid outer core. In this work, we focus on the 200km anomalous layer at the bottom of the outer core that exhibits seismic velocities lower than the PREM model. It has been interpreted as a layer depleted in light elements, whereas the usual model considers that light elements are expelled at the surface of the inner core by freezing of the outer core alloy. Recent models of core formation argued for an early stratified liquid core, and the stratified layers at the top and bottom of the outer core would be a vestige of this primordial stratification. However, freezing of the inner core at the inner core boundary releases light elements that provide buoyancy fluxes that would mix the stratified liquid above with small scale buoyant plumes. To model the F-layer, we consider that the freezing of the iron alloy and the release of light elements have to occur in the bulk of the layer. Iron snow forms and settles in the layer, buffering the thermal and chemical profile to the liquidus. We show that this dynamics can both sustain and stabilize the stratified layer in the liquid outer core while simultaneously matching the seismic observations. However, the expected layer is stable only for a given set of parameters, in particular when a high thermal diffusivity (>100 W/m/K) is employed. If freezing of the iron alloy of the outer core occurs in the bulk of the layer, several assumptions for both the outer and inner core has to be discussed: the F-layer acts as a boundary layer for both composition and temperature, and modifies the quantity of light elements expelled into the outer core as well as the composition that freezes to form the inner core.

  1. Deep convective cloud-top heights and their thermodynamic control during CRYSTAL-FACE

    NASA Astrophysics Data System (ADS)

    Sherwood, Steven C.; Minnis, Patrick; McGill, Matthew

    2004-10-01

    Infrared (11 μm) radiances from GOES-8 and local radiosonde profiles, collected during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) in July 2002, are used to assess the vertical distribution of Florida-area deep convective cloud-top height and test predictions as to its variation based on parcel theory. The highest infrared tops (Z11) reached approximately to the cold point at 15.4 km, though these are uncertain by about 1 km due to unknown cloud-environment temperature differences. Since lidar shows that visible "tops" are generally 1 km or more above Z11, visible cloud tops frequently penetrated the lapse-rate tropopause (˜15 km). Further, since tropospheric ice concentrations were typically present up to ˜1 km above the visible tops, lofting of moisture through the mean cold point was probably common. Morning clouds, and those near Key West, rarely penetrated the tropopause. As in previous studies, nonentraining parcel theory fails to explain either of these results, though it does show promise in explaining day-to-day variations over the peninsula. Moisture variations above the boundary layer account for much of the day-to-day Z11 variability, especially over the oceans. In all locations a 20% increase in mean mixing ratio between 750 and 500 hPa was associated with about 1 km deeper maximum cloud penetration, other things being equal. This sensitivity is too large to explain by simple dilution of parcel buoyancy through mixing, implying microphysical or dynamical feedbacks on cloud development. The evident influence of midtropospheric humidity on the depth of the tropical troposphere suggests an interesting climate feedback possibility for stabilizing midtropospheric relative humidity.

  2. Cholesterol: Top Five Foods to Lower Your Numbers

    MedlinePlus

    Cholesterol: Top foods to improve your numbers Diet can play an important role in lowering your cholesterol. Here are the top foods to lower your cholesterol and protect your heart. By Mayo Clinic Staff ...

  3. 11. TIP TOP MINE. DETAIL OF TONGUE AND GROOVE INTERIOR ...

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

    11. TIP TOP MINE. DETAIL OF TONGUE AND GROOVE INTERIOR SIDING IN LIVING QUARTERS. CAMERA POINTED EAST. - Florida Mountain Mining Sites, Tip Top Mine, West face Florida Mountain, approximately 150 feet below summit, Silver City, Owyhee County, ID

  4. 13. DETAIL VIEW SHOWING HIP VERTICAL, TOP CHORD, SWAY BRACING, ...

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

    13. DETAIL VIEW SHOWING HIP VERTICAL, TOP CHORD, SWAY BRACING, TOP STRUTS, CENTER OF SOUTH TRUSS - Marathon City Bridge, Spanning Big Rib River, on state Trunk Highway 107, Marathon, Marathon County, WI

  5. 2. TIP TOP MINE. NORTH AND EAST SIDE OF HOUSE. ...

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

    2. TIP TOP MINE. NORTH AND EAST SIDE OF HOUSE. CAMERA POINTED SOUTH. - Florida Mountain Mining Sites, Tip Top Mine, West face Florida Mountain, approximately 150 feet below summit, Silver City, Owyhee County, ID

  6. 3. TIP TOP MINE. SOUTH SIDE OF HOUSE. CAMERA POINTED ...

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

    3. TIP TOP MINE. SOUTH SIDE OF HOUSE. CAMERA POINTED NORTH-NORTHWEST. - Florida Mountain Mining Sites, Tip Top Mine, West face Florida Mountain, approximately 150 feet below summit, Silver City, Owyhee County, ID

  7. 1. TIP TOP MINE. WEST SIDE OF STRUCTURE. CAMERA POINTED ...

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

    1. TIP TOP MINE. WEST SIDE OF STRUCTURE. CAMERA POINTED EAST. - Florida Mountain Mining Sites, Tip Top Mine, West face Florida Mountain, approximately 150 feet below summit, Silver City, Owyhee County, ID

  8. 6. TIP TOP MINE. DETAIL OF SIDING. SOUTHWEST CORNER OF ...

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

    6. TIP TOP MINE. DETAIL OF SIDING. SOUTHWEST CORNER OF STRUCTURE. CAMERA POINTED NORTHEAST. - Florida Mountain Mining Sites, Tip Top Mine, West face Florida Mountain, approximately 150 feet below summit, Silver City, Owyhee County, ID

  9. 5. TIP TOP MINE. EAST SIDE OF STRUCTURE WITH COLLAPSED ...

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

    5. TIP TOP MINE. EAST SIDE OF STRUCTURE WITH COLLAPSED ADIT. CAMERA POINTED WEST. - Florida Mountain Mining Sites, Tip Top Mine, West face Florida Mountain, approximately 150 feet below summit, Silver City, Owyhee County, ID

  10. 11. VIEW OF PIN CONNECTION, SOUTH WEB, SHOWING TOP CHORD, ...

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

    11. VIEW OF PIN CONNECTION, SOUTH WEB, SHOWING TOP CHORD, LATTICE BRACING, HIP VERTICAL, EYEBARS, TOP LATERAL BRACING, AND STRUTS, LOOKING SOUTH - Four Mile Bridge, Spanning Elk River on County Road 42, Steamboat Springs, Routt County, CO

  11. 15. DETAIL OF TOP CHORD, SECONDARY VERTICAL POST, DIAGONAL MEMBERS, ...

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

    15. DETAIL OF TOP CHORD, SECONDARY VERTICAL POST, DIAGONAL MEMBERS, AND TOP LATERAL CONNECTION ON WEST SIDE OF TRUSS, VIEW NORTHWEST - Shaytown Road Bridge, Spanning Thornapple River, Vermontville, Eaton County, MI

  12. Altmetric: Top 50 dental articles in 2014.

    PubMed

    Kolahi, J; Khazaei, S

    2016-06-10

    Introduction Altmetrics is a new and emerging scholarly tool that measures online attention surrounding journal articles. Altmetric data resources include: policy documents, news outlets, blogs, online reference managers (eg Mendeley and CiteULike), post-publication peer-review forums (eg PubPeer and Publons), social media (eg Twitter, Facebook, Weibo, Google(+), Pinterest, Reddit), Wikipedia, sites running Stack Exchange (Q&A), and reviews on F1000 and YouTube.Methods To identify the top 50 dental articles in 2014, PubMed was searched using the following query "("2014/1/1"[PDAT]:"2014/12/31"[PDAT]) and jsubsetd[text]" in December, 2015. Consequently, all PubMed records were extracted and sent to Altmetric LLP (London, UK) as a CSV file for examination. Data were analysed by Microsoft Office Excel 2010 using descriptive statistics and charts.Results Using PubMed searches,15,132 dental articles were found in 2014. The mean Altmetric score of 50 top dental articles in 2014 was 69.5 ± 73.3 (95% CI: -74.14 to 213.14). The British Dental Journal (48%) and Journal of Dental Research (16%) had the maximum number of top articles. Twitter (67.13%), Mendeley (15.89%) and news outlets (10.92%) were the most popular altmetric data resources.Discussion Altmetrics are intended to supplement bibliometrics, not replace them. Altmetrics is a fresh and emerging arena for the dental research community. We believe that dental clinical practitioners, research scientists, research directors and journal editors must pay more attention to altmetrics as a new and rapid tool to measure the social impact of scholarly articles.

  13. Conserved variable analysis of the convective boundary layer thermodynamic structure over the tropical oceans

    NASA Technical Reports Server (NTRS)

    Betts, Alan K.; Albrecht, Bruce A.

    1987-01-01

    An analysis of FGGE dropwindsonde data using conserved thermodynamic variables shows mixing line structures for the convective boundary layer over the equatorial Pacific. Deeper boundary layers show a double structure. Reversals of the gradients of mixing ratio and equivalent potential temperature above the boundary-layer top are present in all the averages and suggest that the origin of the air sinking into the boundary layer needs further study.

  14. Planetary Boundary Layer from AERI and MPL

    DOE Data Explorer

    Sawyer, Virginia

    2014-02-13

    The distribution and transport of aerosol emitted to the lower troposphere is governed by the height of the planetary boundary layer (PBL), which limits the dilution of pollutants and influences boundary-layer convection. Because radiative heating and cooling of the surface strongly affect the PBL top height, it follows diurnal and seasonal cycles and may vary by hundreds of meters over a 24-hour period. The cap the PBL imposes on low-level aerosol transport makes aerosol concentration an effective proxy for PBL height: the top of the PBL is marked by a rapid transition from polluted, well-mixed boundary-layer air to the cleaner, more stratified free troposphere. Micropulse lidar (MPL) can provide much higher temporal resolution than radiosonde and better vertical resolution than infrared spectrometer (AERI), but PBL heights from all three instruments at the ARM SGP site are compared to one another for validation. If there is agreement among them, the higher-resolution remote sensing-derived PBL heights can accurately fill in the gaps left by the low frequency of radiosonde launches, and thus improve model parameterizations and our understanding of boundary-layer processes.

  15. Top 10 Replicated Findings from Behavioral Genetics

    PubMed Central

    Plomin, Robert; DeFries, John C.; Knopik, Valerie S.; Neiderhiser, Jenae M.

    2015-01-01

    In the context of current concerns about replication in psychological science, we describe 10 findings from behavioral genetic research that have robustly replicated. These are ‘big’ findings, both in terms of effect size and potential impact on psychological science, such as linearly increasing heritability of intelligence from infancy (20%) through adulthood (60%). Four of our top-10 findings involve the environment, discoveries that could only have been found using genetically sensitive research designs. We also consider reasons specific to behavioral genetics that might explain why these findings replicate. PMID:26817721

  16. Top-down holographic glueball decay rates

    SciTech Connect

    Brünner, F.; Parganlija, D.; Rebhan, A.

    2016-01-22

    We present new results on the decay patterns of scalar and tensor glueballs in the top-down holographic Witten-Sakai-Sugimoto model. This model, which has only one free dimensionless parameter, gives semi-quantitative predictions for the vector meson spectrum, their decay widths, and also a gluon condensate in agreement with SVZ sum rules. The holographic predictions for scalar glueball decay rates are compared with experimental data for the widely discussed gluon candidates f{sub 0}(1500) and f{sub 0}(1710)

  17. Top quark forward-backward asymmetry and same-sign top quark pairs.

    PubMed

    Berger, Edmond L; Cao, Qing-Hong; Chen, Chuan-Ren; Li, Chong Sheng; Zhang, Hao

    2011-05-20

    The top quark forward-backward asymmetry measured at the Tevatron collider shows a large deviation from standard model expectations. Among possible interpretations, a nonuniversal Z' model is of particular interest as it naturally predicts a top quark in the forward region of large rapidity. To reproduce the size of the asymmetry, the couplings of the Z' to standard model quarks must be large, inevitably leading to copious production of same-sign top quark pairs at the energies of the Large Hadron Collider (LHC). We explore the discovery potential for tt and ttj production in early LHC experiments at 7-8 TeV and conclude that if no tt signal is observed with 1 fb⁻¹ of integrated luminosity, then a nonuniversal Z' alone cannot explain the Tevatron forward-backward asymmetry.

  18. 75 FR 4463 - Race to the Top Fund

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... Education 34 CFR Subtitle B, Chapter II Race to the Top Fund; Final Rule and Notice #0;#0;Federal Register... 34 CFR Subtitle B, Chapter II RIN 1810-AB07 Race to the Top Fund AGENCY: Department of Education... Top Fund. Included as Appendix B to the November 18 Final Rule was the Scoring Rubric that...

  19. 77 FR 66182 - Race to the Top-District

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-02

    ... to the Top--District AGENCY: Office of the Deputy Secretary, Department of Education. ACTION: Notice reopening the Race to the Top--District competition. Catalog of Federal Domestic Assistance (CFDA) Number: 84.416. SUMMARY: The Secretary reopens the Race to the Top--District competition to extend...

  20. 29 CFR 1960.54 - Training of top management officials.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Training of top management officials. 1960.54 Section 1960... PROGRAMS AND RELATED MATTERS Training § 1960.54 Training of top management officials. Each agency shall provide top management officials with orientation and other learning experiences which will enable them...

  1. 76 FR 70986 - Race to the Top Fund Phase 3

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-16

    ... 1894-AA01 Race to the Top Fund Phase 3 AGENCY: Department of Education. ACTION: Notice of final... the Top program. In this phase the Department intends to make awards to States that were finalists but did not receive funding under the Race to the Top Fund Phase 2 competition held in fiscal year...

  2. 78 FR 60268 - Race to the Top-District

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-01

    ... to the Top--District AGENCY: Office of the Deputy Secretary, Department of Education. ACTION: Notice extending the deadline of the fiscal year (FY) 2013 Race to the Top--District competition for certain local... extending the application deadline in the FY 2013 Race to the Top--District competition for certain...

  3. 49 CFR 229.71 - Clearance above top of rail.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Clearance above top of rail. 229.71 Section 229.71....71 Clearance above top of rail. No part or appliance of a locomotive except the wheels, flexible nonmetallic sand pipe extension tips, and trip cock arms may be less than 21/2 inches above the top of rail....

  4. 76 FR 56183 - Race to the Top Fund Phase 3

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-12

    ... 1894-AA01 Race to the Top Fund Phase 3 AGENCY: Department of Education. ACTION: Notice of proposed... the Top program. In this phase the Department would make awards to States that were finalists but did not receive funding under the Race to the Top Fund Phase 2 competition held in fiscal year (FY)...

  5. 29 CFR 1960.54 - Training of top management officials.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 9 2011-07-01 2011-07-01 false Training of top management officials. 1960.54 Section 1960... PROGRAMS AND RELATED MATTERS Training § 1960.54 Training of top management officials. Each agency shall provide top management officials with orientation and other learning experiences which will enable them...

  6. 75 FR 16668 - Race to the Top Fund

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-02

    ... CFR Subtitle B, Chapter II RIN 1810-AB10 Race to the Top Fund ACTION: Interim final requirements... for the Race to the Top Fund to incorporate and make binding for Phase 2 of the competition State... include the Docket ID at the top of your comments. Federal eRulemaking Portal: Go to...

  7. 75 FR 30007 - Race to the Top Fund Assessment Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-28

    ... Overview Information Race to the Top Fund Assessment Program Catalog of Federal Domestic Assistance (CFDA... applications for new awards for FY 2010 (NIA) for the Race to the Top Fund Assessment Program. This notice... grant category under the Race to the Top Fund Assessment Program competition. The mailing address...

  8. 76 FR 23487 - Race to the Top Fund

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-27

    ... CFR Subtitle B, Chapter II RIN 1810-AB10 Race to the Top Fund ACTION: Final requirements. SUMMARY: The... requirements for the Race to the Top Fund to incorporate and make binding for Phase 2 of the competition State... for the Race to the Top Fund in the Federal Register (75 FR 16668). The interim final...

  9. 49 CFR 229.71 - Clearance above top of rail.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Clearance above top of rail. 229.71 Section 229.71....71 Clearance above top of rail. No part or appliance of a locomotive except the wheels, flexible nonmetallic sand pipe extension tips, and trip cock arms may be less than 21/2 inches above the top of rail....

  10. Top Contributors to the School Psychology Literature: 1996-2005

    ERIC Educational Resources Information Center

    Roberts, Gabrielle A.; Davis, Kim S.; Zanger, Dinorah; Gerrard-Morris, Aimee; Robinson, Daniel H.

    2006-01-01

    S.G. Little (1997) reported the top contributors to the school psychology literature from 1987 to 1995. The present study represents a follow-up by examining the top contributors from 1996 to 2005. Similar to Little, a list of the top 50 contributors was developed using a point system that assigned more credit based on fewer coauthors and higher…

  11. 12. TIP TOP MINE. WOODEN STRUCTURE ASSOCIATED WITH CABLES IN ...

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

    12. TIP TOP MINE. WOODEN STRUCTURE ASSOCIATED WITH CABLES IN ID-31-C-13 AND ID-31-C-14 LOCATED ON SLOPE JUST BELOW TIP TOP HOUSE. CAMERA IS POINTED NORTH-NORTHWEST. - Florida Mountain Mining Sites, Tip Top Mine, West face Florida Mountain, approximately 150 feet below summit, Silver City, Owyhee County, ID

  12. 29 CFR 1960.54 - Training of top management officials.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROGRAMS AND RELATED MATTERS Training § 1960.54 Training of top management officials. Each agency shall provide top management officials with orientation and other learning experiences which will enable them to... 29 Labor 9 2013-07-01 2013-07-01 false Training of top management officials. 1960.54 Section...

  13. 29 CFR 1960.54 - Training of top management officials.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... PROGRAMS AND RELATED MATTERS Training § 1960.54 Training of top management officials. Each agency shall provide top management officials with orientation and other learning experiences which will enable them to... 29 Labor 9 2012-07-01 2012-07-01 false Training of top management officials. 1960.54 Section...

  14. It's about Time: The Literacy TopPics Awards.

    ERIC Educational Resources Information Center

    And Others; Swafford, Jeanne

    1997-01-01

    Examines the last five years of articles in this journal to show what topics were most often written about (the "Top Picks" or "TopPics"). Discusses these results and makes recommendations that deserve considerable attention in the future. Notes that integrated language arts was a perennial TopPic. (SR)

  15. 49 CFR 178.1050 - Top lift test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Containers § 178.1050 Top lift test. (a) General. The top lift test must be conducted for the qualification... permissible gross mass, the load being evenly distributed. (c) Test method. (1) A Flexible Bulk Container must... 49 Transportation 3 2013-10-01 2013-10-01 false Top lift test. 178.1050 Section...

  16. 49 CFR 178.975 - Top lift test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Packagings § 178.975 Top lift test. (a) General. The top lift test must be conducted for the qualification of... distributed. (c) Test method. (1) A Large Packaging must be lifted in the manner for which it is designed... 49 Transportation 3 2013-10-01 2013-10-01 false Top lift test. 178.975 Section...

  17. Inhibiting lung lining fluid glutathione metabolism with GGsTop as a novel treatment for asthma.

    PubMed

    Tuzova, Marina; Jean, Jyh-Chang; Hughey, Rebecca P; Brown, Lou Ann S; Cruikshank, William W; Hiratake, Jun; Joyce-Brady, Martin

    2014-01-01

    Asthma is characterized by airway inflammation. Inflammation is associated with oxidant stress. Airway epithelial cells are shielded from this stress by a thin layer of lung lining fluid (LLF) which contains an abundance of the antioxidant glutathione. LLF glutathione metabolism is regulated by γ-glutamyl transferase (GGT). Loss of LLF GGT activity in the mutant GGT(enu1) mouse causes an increase in baseline LLF glutathione content which is magnified in an IL-13 model of allergic airway inflammation and protective against asthma. Normal mice are susceptible to asthma in this model but can be protected with acivicin, a GGT inhibitor. GGT is a target to treat asthma but acivicin toxicity limits clinical use. GGsTop is a novel GGT inhibitor. GGsTop inhibits LLF GGT activity only when delivered through the airway. In the IL-13 model, mice treated with IL-13 and GGsTop exhibit a lung inflammatory response similar to that of mice treated with IL-13 alone. But mice treated with IL-13 and GGsTop show attenuation of methacholine-stimulated airway hyper-reactivity, inhibition of Muc5ac and Muc5b gene induction, decreased airway epithelial cell mucous accumulation and a fourfold increase in LLF glutathione content compared to mice treated with IL-13 alone. Mice treated with GGsTop alone are no different from that of mice treated with saline alone, and show no signs of toxicity. GGsTop could represent a valuable pharmacological tool to inhibit LLF GGT activity in pulmonary disease models. The associated increase in LLF glutathione can protect lung airway epithelial cells against oxidant injury associated with inflammation in asthma.

  18. Collider Detector at Fermilab (CDF): Data from the Top Group's Top Quark Research

    DOE Data Explorer

    The Collider Detector at Fermilab (CDF) is a Tevatron experiment at Fermilab. The Tevatron, a powerful particle accelerator, accelerates protons and antiprotons close to the speed of light, and then makes them collide head-on inside the CDF detector. The CDF detector is used to study the products of such collisions. The CDF Physics Group at Fermilab is organized into six working groups, each with a specific focus. The Top group studies the properties of the top quark, the heaviest known fundamental particle. Their public web page makes data and numerous figures available from both CDF Runs I and II.

  19. Microstructure Effect of Intermediate Coat Layer on Corrosion Behavior of HVAF-Sprayed Bi-Layer Coatings

    NASA Astrophysics Data System (ADS)

    Sadeghimeresht, Esmaeil; Markocsan, Nicolaie; Nylén, Per

    2017-01-01

    The inherent pores and carbides of Cr3C2-NiCr coatings significantly reduce the corrosion resistance, the former by providing preferential paths for ion diffusion and the latter by forming cathodic sites in galvanic couples (between NiCr and Cr3C2). Adding a dense intermediate layer (intermediate coat layer) between the Cr3C2-NiCr coating (top coat) and substrate increases the corrosion protection of the coating if the layer acts as cathode in connection to the top coat. In the present work, NiCr, NiAl, and NiCoCrAlY layers were deposited by high-velocity air-fuel process as intermediate coat layers for the Cr3C2-NiCr top coat. Effects of coating microstructure on corrosion behavior of single- and bi-layer coatings were studied by open-circuit potential and polarization tests in 3.5 wt.% NaCl at room temperature. A zero resistance ammeter technique was used to study the galvanic corrosion of the coupled top and intermediate coat layers. Methods such as SEM and XRD were employed to characterize the as-sprayed and corroded coatings and to investigate the corrosion mechanisms. The results showed that the NiCoCrAlY coating not only presented a more positive corrosion potential ( Ecorr) than the Cr3C2-NiCr coating, but also provided a better passive layer than the single-phase NiCr and NiAl coatings.

  20. Top marine predators track Lagrangian coherent structures

    PubMed Central

    Tew Kai, Emilie; Rossi, Vincent; Sudre, Joel; Weimerskirch, Henri; Lopez, Cristobal; Hernandez-Garcia, Emilio; Marsac, Francis; Garçon, Veronique

    2009-01-01

    Meso- and submesoscales (fronts, eddies, filaments) in surface ocean flow have a crucial influence on marine ecosystems. Their dynamics partly control the foraging behavior and the displacement of marine top predators (tuna, birds, turtles, and cetaceans). In this work we focus on the role of submesoscale structures in the Mozambique Channel in the distribution of a marine predator, the Great Frigatebird. Using a newly developed dynamic concept, the finite-size Lyapunov exponent (FSLE), we identified Lagrangian coherent structures (LCSs) present in the surface flow in the channel over a 2-month observation period (August and September 2003). By comparing seabird satellite positions with LCS locations, we demonstrate that frigatebirds track precisely these structures in the Mozambique Channel, providing the first evidence that a top predator is able to track these FSLE ridges to locate food patches. After comparing bird positions during long and short trips and different parts of these trips, we propose several hypotheses to understand how frigatebirds can follow these LCSs. The birds might use visual and/or olfactory cues and/or atmospheric current changes over the structures to move along these biologic corridors. The birds being often associated with tuna schools around foraging areas, a thorough comprehension of their foraging behavior and movement during the breeding season is crucial not only to seabird ecology but also to an appropriate ecosystemic approach to fisheries in the channel. PMID:19416811

  1. Top marine predators track Lagrangian coherent structures.

    PubMed

    Tew Kai, Emilie; Rossi, Vincent; Sudre, Joel; Weimerskirch, Henri; Lopez, Cristobal; Hernandez-Garcia, Emilio; Marsac, Francis; Garçon, Veronique

    2009-05-19

    Meso- and submesoscales (fronts, eddies, filaments) in surface ocean flow have a crucial influence on marine ecosystems. Their dynamics partly control the foraging behavior and the displacement of marine top predators (tuna, birds, turtles, and cetaceans). In this work we focus on the role of submesoscale structures in the Mozambique Channel in the distribution of a marine predator, the Great Frigatebird. Using a newly developed dynamic concept, the finite-size Lyapunov exponent (FSLE), we identified Lagrangian coherent structures (LCSs) present in the surface flow in the channel over a 2-month observation period (August and September 2003). By comparing seabird satellite positions with LCS locations, we demonstrate that frigatebirds track precisely these structures in the Mozambique Channel, providing the first evidence that a top predator is able to track these FSLE ridges to locate food patches. After comparing bird positions during long and short trips and different parts of these trips, we propose several hypotheses to understand how frigatebirds can follow these LCSs. The birds might use visual and/or olfactory cues and/or atmospheric current changes over the structures to move along these biologic corridors. The birds being often associated with tuna schools around foraging areas, a thorough comprehension of their foraging behavior and movement during the breeding season is crucial not only to seabird ecology but also to an appropriate ecosystemic approach to fisheries in the channel.

  2. Ash plume top height estimation using AATSR

    NASA Astrophysics Data System (ADS)

    Virtanen, T. H.; Kolmonen, P.; Rodríguez, E.; Sogacheva, L.; Sundström, A.-M.; de Leeuw, G.

    2014-08-01

    An algorithm is presented for the estimation of volcanic ash plume top height using the stereo view of the Advanced Along Track Scanning Radiometer (AATSR) aboard Envisat. The algorithm is based on matching top of the atmosphere (TOA) reflectances and brightness temperatures of the nadir and 55° forward views, and using the resulting parallax to obtain the height estimate. Various retrieval parameters are discussed in detail, several quality parameters are introduced, and post-processing methods for screening out unreliable data have been developed. The method is compared to other satellite observations and in situ data. The proposed algorithm is designed to be fully automatic and can be implemented in operational retrieval algorithms. Combined with automated ash detection using the brightness temperature difference between the 11 and 12 μm channels, the algorithm allows efficient simultaneous retrieval of the horizontal and vertical dispersion of volcanic ash. A case study on the eruption of the Icelandic volcano Eyjafjallajökull in 2010 is presented.

  3. Ash plume top height estimate using AATSR

    NASA Astrophysics Data System (ADS)

    Virtanen, T. H.; Kolmonen, P.; Rodríguez, E.; Sogacheva, L.; Sundström, A.-M.; de Leeuw, G.

    2014-04-01

    An algorithm is presented for estimation of volcanic ash plume top height using the stereo view of the Advanced Along Track Scanning Radiometer (AATSR) aboard ENVISAT. The algorithm is based on matching the top of atmosphere (TOA) reflectances and brightness temperatures of the nadir and 55° forward views, and using the resulting parallax to obtain the height estimate. Various retrieval parameters are discussed in detail, several quality parameters are introduced, and post-processing methods for screening out unreliable data have been developed. The method is compared against other satellite observations and in-situ data. The proposed algorithm is designed to be fully automatic, and can be implemented into operational retrieval algorithms. Combined with automated ash detection using the brightness temperature difference between the 11 μm and 12 μm channels, the algorithm allows simultaneous retrieval of horizontal and vertical dispersion of volcanic ash efficiently. A case study on the eruption of the Icelandic volcano Eyjafjallajökull in 2010 is presented. The height estimate method results are validated against available satellite and ground based data.

  4. Top-down control in contour grouping.

    PubMed

    Volberg, Gregor; Wutz, Andreas; Greenlee, Mark W

    2013-01-01

    Human observers tend to group oriented line segments into full contours if they follow the Gestalt rule of 'good continuation'. It is commonly assumed that contour grouping emerges automatically in early visual cortex. In contrast, recent work in animal models suggests that contour grouping requires learning and thus involves top-down control from higher brain structures. Here we explore mechanisms of top-down control in perceptual grouping by investigating synchronicity within EEG oscillations. Human participants saw two micro-Gabor arrays in a random order, with the task to indicate whether the first (S1) or the second stimulus (S2) contained a contour of collinearly aligned elements. Contour compared to non-contour S1 produced a larger posterior post-stimulus beta power (15-21 Hz). Contour S2 was associated with a pre-stimulus decrease in posterior alpha power (11-12 Hz) and in fronto-posterior theta (4-5 Hz) phase couplings, but not with a post-stimulus increase in beta power. The results indicate that subjects used prior knowledge from S1 processing for S2 contour grouping. Expanding previous work on theta oscillations, we propose that long-range theta synchrony shapes neural responses to perceptual groupings regulating lateral inhibition in early visual cortex.

  5. Top Down Proteomics: Facts and Perspectives

    PubMed Central

    Catherman, Adam D.; Skinner, Owen S.; Kelleher, Neil L.

    2014-01-01

    The rise of the “Top Down” method in the field of mass spectrometry-based proteomics has ushered in a new age of promise and challenge for the characterization and identification of proteins. Injecting intact proteins into the mass spectrometer allows for better characterization of post-translational modifications and avoids several of the serious “inference” problems associated with peptide-based proteomics. However, successful implementation of a Top Down approach to endogenous or other biologically relevant samples often requires the use of one or more forms of separation prior to mass spectrometric analysis, which have only begun to mature for whole protein MS. Recent advances in instrumentation have been used in conjunction with new ion fragmentation using photons and electrons that allow for better (and often complete) protein characterization on cases simply not tractable even just a few years ago. Finally, the use of native electrospray mass spectrometry has shown great promise for the identification and characterization of whole protein complexes in the 100 kDa to 1 MDa regime, with prospects for complete compositional analysis for endogenous protein assemblies a viable goal over the coming few years. PMID:24556311

  6. Top production and decay at CDF

    SciTech Connect

    Castro, A.

    1996-09-01

    We report on the measurement of top production and decay properties obtained by the CDF experiment with {ital p{anti p}} collisions at {radical}{ital s} = 1.8 TeV. the analyses presented here refer to {integral}{ital Ldt}{approx} 110 {ital pb}{sup -1} collected at the Fermilab Tevatron collider. About 85% of the possible {ital t{anti t}} decays have been studied in different channels according to the number of high-{ital p{sub T}} leptons found in the final state. Combining the results from the channels with at least one {ital W} decaying leptonically into an {ital e} or {mu} we measure {delta}{sub {ital t{anti t}}} = 7.5 {sup +1.9}{sub -1.6}{ital pb}. We report also on the observation of {ital t{anti t}} production in all of the hadronic decay channels using kinematic selection and {ital b} identification, and in the channel containing one hadronically decaying {tau} lepton. Finally we discuss the kinematics of top events and measure the matrix element {vert_bar}V{sub {ital tb}}{vert_bar} = 1.12 {+-} 0.12.

  7. Spectra of Flat Top & nearby soils

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The first color panorama returned by the Imager for Mars Pathfinder (IMP) after Mars Pathfinder's landing included several larger, gray rocks, bright red dust on a flat-topped rock and the ground between the rocks, and darker red soil exposed where Pathfinder's landing dislodged a small rock. The rock dubbed 'Flat Top' is at the low center of the images. The less red color and low reflectance of the rocks is consistent with the iron minerals found in igneous rocks, whereas the fine, bright drift has a spectrum indicative of a weathering product. The strength of the bend, or 'kink', in the spectrum is related to the abundance and particle size of specific crustalline, ferric weathering products. In the false color image, the blue areas have a weak kink and are relatively unweathered, whereas the red areas' strong kink indicates an abundance of ferric iron minerals.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

  8. The top 100 cited articles in urology.

    PubMed

    Hennessey, Kiara; Afshar, Kourosh; Macneily, Andrew E

    2009-08-01

    BACKGROUND: We identified and analyzed the characteristics of the 100 most frequently cited articles published between 1965 and 2007 in journals pertaining to urology and related fields. METHODS: We selected 69 of the highest impact urology and sub-specialty journals and 22 of the highest impact general medical and medical research journals from the 2006 edition of Journal Citation Reports: Science edition. We identified the 100 most frequently cited urological articles published in these 91 journals using the Science Citation Index Expanded (1965-present). We reviewed and analyzed the articles. RESULTS: The top 100 articles were cited a mean of 629 times (range 418-1435) and published between 1965 and 2003, with 89% published after 1979 and 54% published in the 1990s. Fifteen journals were represented, led by The New England Journal of Medicine (30), The Journal of Urology (22) and Lancet (11). Ninety publications originated from North America (81) or the United Kingdom (9). Johns Hopkins University (13), Harvard University (5), Stanford University (5) and University of California, Los Angeles (5) published the most articles. Five urologists were first authors of 2 or more of the articles. Fifty-six articles reported observational studies. Oncology (51) and transplantation (20) were the most commonly represented urological subfields. CONCLUSION: These top-cited articles in urology identify topics and authors that contributed to major advances in urology. Observational studies and randomized controlled trials in oncology published in high-impact urological or medical journals constitute the most common type of highly cited publications.

  9. Measurements of top quark properties in top pair production and decay at the LHC using the CMS detector

    SciTech Connect

    Jindariani, Sergo

    2016-05-31

    Measurements are presented of the properties of top quarks in pair production and decay from proton-proton collisions at the LHC. The data were collected at centre-of-mass energies of 7 and 8 TeV by the CMS experiment during the years 2011 and 2012. The top quark-antiquark charge asymmetry is measured using the difference of the absolute rapidities of the reconstructed top and anti-top kinematics, as well as from distributions of the top quark decay products. The measurements are performed in the decay channels of the tt¯ pair into both one and two leptons in the final state. The polarization of top quarks and top pair spin correlations are measured from the angular distributions of top quark decay products. The W-boson helicity fractions and angular asymmetries are extracted and limits on anomalous contributions to the Wtb vertex are determined. The flavor content in top-quark pair events is measured using the fraction of top quarks decaying into a W-boson and a b -quark relative to all top quark decays, R=B(t→Wb)/B(t→Wq) , and the result is used to determine the CKM matrix element Vtb as well as the width of the top quark resonance. Finally, all of the results are found to be in good agreement with standard model predictions.

  10. Top 10% Admissions in the Borderlands: Access and Success of Borderland Top Students at Texas Public Universities

    ERIC Educational Resources Information Center

    Rodríguez, Cristóbal

    2016-01-01

    This study focuses on Texas Borderland students admitted through the Texas Top 10% admissions policy, which assumes that Top 10% students are college ready for any public university and provides Top 10% high school graduates automatic admission to any 4-year public university in Texas. Using descriptive and inferential statistics, results…

  11. Precision Measurements of Top Quark Production with the ATLAS Detector

    NASA Astrophysics Data System (ADS)

    Stolte, Philipp

    2017-03-01

    The top quark is the heaviest known fundamental particle. It is the only quark that decays before it hadronises which gives us the unique opportunity to probe the properties of bare quarks and to test perturbative QCD. This overview will focus on a few recent precision top quark measurements by the ATLAS Collaboration at the LHC: Fiducial top pair and single top production cross-sections including differential distributions will be presented and compared with QCD predictions. The results include the first top quark measurements at 13 TeV using data from LHC Run 2.

  12. Partially coherent flat-topped beam and its propagation.

    PubMed

    Ge, Di; Cai, Yangjian; Lin, Qiang

    2004-08-20

    A partially coherent beam with flat-topped profile is proposed. The cross-spectral density of this beam can be expressed as a finite series of the cross-spectral density of partially coherent Gaussian-Schell-model beams with different parameters. Analytical propagation formulas for partially coherent flat-topped beams are derived through aligned and misaligned optical systems. The propagation property of partially coherent flat-topped beams in free space is illustrated numerically. The fractional Fourier transform of partially coherent fiat-topped beams is also studied. Our method provides a convenient way to describe partially coherent flat-topped beams and treat their propagation and transformation.

  13. Summary of Single top quark production at the Tevatron

    SciTech Connect

    Schwienhorst, R.; CDF, on the

    2014-01-01

    The production of single-top quarks occurs via the weak interaction at the Fermilab Tevatron proton-antiproton collider. Single top quark events are selected in the lepton+jets final state by CDF and D0 and in the missing transverse energy plus jets final state by CDF. Multivariate classifiers separate the s-channel and t-channel single-top signals from the large backgrounds. The combination of CDF and D0 results leads to the first observation of the s-channel mode of single top quark production. The t-channel and single top combined cross sections have also been measured.

  14. Energy dissipation in intercalated carbon nanotube forests with metal layers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vertically aligned carbon nanotube (CNT) forests were synthesized to study their quasi-static mechanical properties in a layered configuration with metallization. The top and bottom surfaces of CNT forests were metalized with Ag, Fe, and In using paste, sputtering, and thermal evaporation, respectiv...

  15. A perspective view of the plane mixing layer

    NASA Technical Reports Server (NTRS)

    Jimenez, J.; Cogollos, M.; Bernal, L. P.

    1984-01-01

    A three-dimensional model of the plane mixing layer is constructed by applying digital image processing and computer graphic techniques to laser fluorescent motion pictures of its transversal sections. A system of streamwise vortex pairs is shown to exist on top of the classical spanwise eddies. Its influence on mixing is examined.

  16. Effect on Sb on the Properties of GaInP Top Cells: Preprint

    SciTech Connect

    Olson, J. M.; McMahon, W. E.; Kurtz, S.

    2006-05-01

    It is well known that the efficiency of GaInP/GaAs tandem solar cells is limited by the band gap of the GaInP top cell, which, in turn, is determined by the degree of compositional ordering in GaInP base layer. Attempts to raise the band gap by the addition of Al to the top cell have met with limited success due to the strong affinity between Al and oxygen. Here we investigate a different approach. It has been shown that the presence of antimony on the surface of GaInP during its growth suppresses the ordering process and increases the band gap. In this paper, we study the effects of Sb on the properties of GaInP top cells. We show that, in addition to raising the band gap of GaInP, it also increases the incorporation of Zn and changes the relative incorporation of Ga and In. These effects depend strongly on the substrate orientation, growth temperature and rate, and the Sb/P ratio in the gas phase. We show that the band gap of the GaInP top cell (and the Voc) can be increased without reducing the minority carrier collection efficiency. The implications of these results are presented and discussed.

  17. Determining the Fine Structure of the Entrainment Zone in Cloud-Topped Boundary Layers

    DTIC Science & Technology

    2005-03-01

    1. (a) liquid water content (g kg-1), (b) virtual potential temperature (K), (c) specific humidity of water vapor (g kg-1), (d) ozone (ppbv), (e...12 Jun 92 at 2140 UTC. (a) liquid water content (g kg-1), (b) virtual potential temperature (K), (c) specific humidity of water vapor (g kg-1), (d...in this study are virtual potential temperature , liquid water content, specific humidity of water vapor, three-dimensional wind vectors, altitude

  18. Remote Sensing of Cloud Top Heights Using the Research Scanning Polarimeter

    NASA Technical Reports Server (NTRS)

    Sinclair, Kenneth; van Diedenhoven, Bastiaan; Cairns, Brian; Yorks, John; Wasilewski, Andrzej

    2015-01-01

    Clouds cover roughly two thirds of the globe and act as an important regulator of Earth's radiation budget. Of these, multilayered clouds occur about half of the time and are predominantly two-layered. Changes in cloud top height (CTH) have been predicted by models to have a globally averaged positive feedback, however observational changes in CTH have shown uncertain results. Additional CTH observations are necessary to better and quantify the effect. Improved CTH observations will also allow for improved sub-grid parameterizations in large-scale models and accurate CTH information is important when studying variations in freezing point and cloud microphysics. NASA's airborne Research Scanning Polarimeter (RSP) is able to measure cloud top height using a novel multi-angular contrast approach. RSP scans along the aircraft track and obtains measurements at 152 viewing angles at any aircraft location. The approach presented here aggregates measurements from multiple scans to a single location at cloud altitude using a correlation function designed to identify the location-distinct features in each scan. During NASAs SEAC4RS air campaign, the RSP was mounted on the ER-2 aircraft along with the Cloud Physics Lidar (CPL), which made simultaneous measurements of CTH. The RSPs unique method of determining CTH is presented. The capabilities of using single and combinations of channels within the approach are investigated. A detailed comparison of RSP retrieved CTHs with those of CPL reveal the accuracy of the approach. Results indicate a strong ability for the RSP to accurately identify cloud heights. Interestingly, the analysis reveals an ability for the approach to identify multiple cloud layers in a single scene and estimate the CTH of each layer. Capabilities and limitations of identifying single and multiple cloud layers heights are explored. Special focus is given to sources of error in the method including optically thin clouds, physically thick clouds, multi-layered

  19. Environmental Barrier Coatings Having a YSZ Top Coat

    NASA Technical Reports Server (NTRS)

    Lee, Kang N.; Gray, Hugh (Technical Monitor)

    2002-01-01

    Environmental barrier coatings (EBCs) with a Si bond coat, a yttria-stabilized zirconia (YSZ) top coat, and various intermediate coats were investigated. EBCs were processed by atmospheric pressure plasma spraying. The EBC durability was determined by thermal cycling tests in water vapor at 1300 C and 1400 C, and in air at 1400 C and 1500 C. EBCs with a mullite (3Al2O3 (dot) 2SiO2) + BSAS (1 - xBaO (dot) xSrO (dot) Al2O3 (dot) 2SiO2) intermediate coat were more durable than EBCs with a mullite intermediate coat, while EBCs with a mullite/BSAS duplex intermediate coat resulted in inferior durability. The improvement with a mullite + BSAS intermediate coat was attributed to enhanced compliance of the intermediate coat due to the addition of a low modulus BSAS second phase. Mullite + BSAS/YSZ and BSAS/YSZ interfaces produced a low melting (less than 1400 C) reaction product, which is expected to degrade the EBC performance by increasing the thermal conductivity. EBCs with a mullite + BSAS / graded mullite + YSZ intermediate coat showed the best durability among the EBCs investigated in this study. This improvement was attributed to diffused CTE (Coefficient of Thermal Expansion) mismatch stress and improved chemical stability due to the compositionally graded mullite+YSZ layer.

  20. Ozone-destroying chlorine tops out

    SciTech Connect

    Kerr, R.A.

    1996-01-05

    This article explores the reality of whether the Montreal Protocol to protect the ozone layer has worked. The prime evidence for the success of the 1987 Protocal is that atmospheric chlorine has peaked and is on the way down. However, there are some concerns that gaps in the existing protocal could slow the recovery.

  1. A view from the top: CDF results of top counting experiment

    SciTech Connect

    Chiarelli, G.; CDF Collaboration

    1995-09-01

    We present the CDF results relative to the observation of the top quark and its Properties obtained with 100 pb{sup {minus}1} of data collected in the period 1992--1993 and 1994--1995. Updated results of the counting experiments are given, and consistency between this data and earlier published mass and cross section is shown.

  2. Structure of the Arabidopsis thaliana TOP2 oligopeptidase

    PubMed Central

    Wang, Ruiying; Rajagopalan, Krithika; Sadre-Bazzaz, Kianoush; Moreau, Magali; Klessig, Daniel F.; Tong, Liang

    2014-01-01

    Thimet oligopeptidase (TOP) is a zinc-dependent metallopeptidase. Recent studies suggest that Arabidopsis thaliana TOP1 and TOP2 are targets for salicylic acid (SA) binding and participate in SA-mediated plant innate immunity. The crystal structure of A. thaliana TOP2 has been determined at 3.0 Å resolution. Comparisons to the structure of human TOP revealed good overall structural conservation, especially in the active-site region, despite their weak sequence conservation. The protein sample was incubated with the photo-activated SA analog 4-azido-SA and exposed to UV irradiation before crystallization. However, there was no conclusive evidence for the binding of SA based on the X-ray diffraction data. Further studies are needed to elucidate the molecular mechanism of how SA regulates the activity of A. thaliana TOP1 and TOP2. PMID:24817709

  3. Unified Cloud and Mixing Parameterizations of the Marine Boundary Layer: EDMF and PDF-based Cloud Approaches

    DTIC Science & Technology

    2012-09-30

    600 m, topped by a non-precipitating shallow cumulus cloud layer. The boundary layer turbulence is forced mainly by buoyancy flux, the wind shear...STATEMENT A. Approved for public release; distribution is unlimited. Unified Cloud and...Mixing Parameterizations of the Marine Boundary Layer: EDMF and PDF-based cloud approaches Joao Teixeira Jet Propulsion Laboratory, California

  4. Nonlinear Instability of Liquid Layers.

    NASA Astrophysics Data System (ADS)

    Newhouse, Lori Ann

    The nonlinear instability of two superposed viscous liquid layers in planar and axisymmetric configurations is investigated. In the planar configuration, the light layer fluid is bounded below by a wall and above by a heavy semiinfinite fluid. Gravity drives the instability. In the first axisymmetric configuration, the layer is confined between a cylindrical wall and a core of another fluid. In the second, a thread is suspended in an infinite fluid. Surface tension forces drive the instability in the axisymmetric configurations. The nonlinear evolution of the fluid-fluid interface is computed for layers of arbitrary thickness when their dynamics are fully coupled to those of the second fluid. Under the assumption of creeping flow, the flow field is represented by an interfacial distribution of Green's functions. A Fredholm integral equation of the second kind for the strength of the distribution is derived and then solved using an iterative technique. The Green's functions produce flow fields which are periodic in the direction parallel to the wall and have zero velocity on the wall. For small and moderate surface tension, planar layers evolve into a periodic array of viscous plumes which penetrate into the overlying fluid. The morphology of the plumes depends on the surface tension and the ratio of the fluid viscosities. As the viscosity of the layer increases, the plumes change from a well defined drop on top of a narrow stem to a compact column of rising fluid. The capillary instability of cylindrical interfaces and interfaces in which the core thickness varies in the axial direction are investigated. In both the unbounded and wall bounded configurations, the core evolves into a periodic array of elongated fluid drops connected by thin, almost cylindrical fluid links. The characteristics of the drop-link structure depend on the core thickness, the ratio of the core radius to the wall radius, and the ratio of the fluid viscosities. The factors controlling the

  5. Inclined lidar observations of boundary layer aerosol particles above the Kongsfjord, Svalbard

    NASA Astrophysics Data System (ADS)

    Lampert, Astrid; Ström, Johan; Ritter, Christoph; Neuber, Roland; Yoon, Young; Chae, Nam; Shiobara, Masataka

    2012-10-01

    An inclined lidar with vertical resolution of 0.4 m was used for detailed boundary layer studies and to link observations at Zeppelin Mountain (474 m) and Ny-Ålesund, Svalbard. We report on the observation of aerosol layers directly above the Kongsfjord. On 29 April 2007, a layer of enhanced backscatter was observed in the lowest 25 m above the open water surface. The low depolarization ratio indicated spherical particles. In the afternoon, this layer disappeared. The ultrafine particle concentration at Zeppelin and Corbel station (close to the Kongsfjord) was low. On 1 May 2007, a drying process in the boundary layer was observed. In the morning, the atmosphere up to Zeppelin Mountain showed enhanced values of the backscatter coefficient. Around noon, the top of the highly reflecting boundary layer decreased from 350 to 250 m. The top of the boundary layer observed by lidar was confirmed by radiosonde data.

  6. Surface-interface exploration of Mg deposited on Si(100) and oxidation effect on interfacial layer

    SciTech Connect

    Sarpi, B.; Daineche, R.; Girardeaux, C.; Bertoglio, M.; Derivaux, F.; Vizzini, S.; Biberian, J. P.; Hemeryck, A.

    2015-01-12

    Using scanning tunneling microscopy and spectroscopy, Auger electron spectroscopy, and low energy electron diffraction, we have studied the growth of Mg deposited on Si(100)-(2 × 1). Coverage from 0.05 monolayer (ML) to 3 ML was investigated at room temperature. The growth mode of the magnesium is a two steps process. At very low coverage, there is formation of an amorphous ultrathin silicide layer with a band gap of 0.74 eV, followed by a layer-by-layer growth of Mg on top of this silicide layer. Topographic images reveal that each metallic Mg layer is formed by 2D islands coalescence process on top of the silicide interfacial layer. During oxidation of the Mg monolayer, the interfacial silicide layer acts as diffusion barrier for the oxygen atoms with a decomposition of the silicide film to a magnesium oxide as function of O{sub 2} exposure.

  7. Environmental assessment of curly top virus control in California. [Curly Top Virus

    SciTech Connect

    Not Available

    1991-03-15

    Curly top is a viral disease of sugarbeets, tomatoes, melons, peppers, beans, cucumbers, squash, pumpkins, spinach, vineseed and other commercially important crops, including ornamentals. Curly top not only infects commercial crops, but at times devastates backyard vegetable and flower gardens. The only known vector of curly top is Circulifer tenellus, commonly known as the beet leafhopper. Control of the beet leafhopper may take place at various locations throughout the San Joaquin Valley, Salinas Valley, Cuyama Valley, Antelope Valley of northern Los Angeles County, Riverside County and the Imperial Valley (See Maps in Appendix E''), including portions of Merced, Fresno, Kings. Kern, San Luis Obispo, Monterey, San Benito, Santa Barbara, Los Angeles, Riverside and Imperial Counties. The size of the control program is totally dependent on the location, size, nd distribution of the beet leafhopper population. In a year with a low population, only 80,000 acres in western Fresno, Kings, and Kern Counties may require treatment. In a drought year, the treatment required may increase to more than 200,000 acres and include some inter-coastal valleys of Monterey, San Luis Obispo and Santa Barbara Counties. Not all areas require treatment on an annual basis and at no time is the entire area subject to blanket treatment. The Curly Top Virus Control Program (CTVCP) was instrumental in supporting research which developed an antisera allowing the use of Enzyme-Linked Immunosorbent Assay to determine the presence, on a percentage basis, of curly top virus. Thus, the amount of virus found in a given area lends weight to treatment priorities.

  8. Study of acid diffusion behaves form PAG by using top coat method

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Atsushi; Matsumoto, Yoko

    2014-03-01

    Our past research on measurements of simulation parameters for ArF resists focused on establishing methods for measuring the following parameters:[1]-[4] • Development parameters[1] • PEB parameters[2] • Dill's ABC parameters[3] • Quencher parameter[4] We entered these parameters into a lithography simulator and performed ArF resist simulations.We then explored ways to optimize the ArF resist material and process. This paper reports on our study of methods for measuring the diffusion length of acid generated from PAG during exposures. In our experiment, we applied a PAG-containing top coat (TC) material (second layer) to a PAG-free ArF resist (first layer), then performed the exposure and PEB processes. The acid generated in the TC during the exposure diffused into the ArF resist in the lower layer (first layer) when PEB was performed. The process of developing this sample removed the TC in the second layer and the parts of the first layer into which the acid had diffused.We obtained the acid diffusion length based on the quantity of film removed by the development. We calculated the acid diffusion coefficient after varying the exposure value and repeating the measurement. For this report, we also performed measurements to determine how differences in PAG anion size, amount of quencher additive, and PEB temperature affected the acid diffusion coefficient.We entered the measurements obtained into the PROLITH simulator and explored the effects of acid diffusion on pattern profile.

  9. Top partners searches and composite Higgs models

    NASA Astrophysics Data System (ADS)

    Matsedonskyi, Oleksii; Panico, Giuliano; Wulzer, Andrea

    2016-04-01

    Colored fermionic partners of the top quark are well-known signatures of the Composite Higgs scenario and for this reason they have been and will be subject of an intensive experimental study at the LHC. Performing an assessment of the theoretical implications of this experimental effort is the goal of the present paper. We proceed by analyzing a set of simple benchmark models, characterized by simple two-dimensional parameter spaces where the results of the searches are conveniently visualized and their impact quantified. We only draw exclusion contours, in the hypothesis of no signal, but of course our formalism could equally well be used to report discoveries in a theoretically useful format.

  10. Studies on selenium in top athletes.

    PubMed

    Drâgan, I; Ploeşteanu, E; Cristea, E; Mohora, M; Dinu, V; Troescu, V S

    1988-01-01

    The authors performed a controlled trial in 18 top athletes (9 weight lifters and 9 rowers, girls) in order to make evident some chronic and acute effects (antioxidant) of selenium. Nonprotein--SH (essential glutathione), lipid peroxides (MDA-malondialdehyde), glucose-6-phosphate dehydrogenases (G-6-PDH) and fructose-1,6-diphosphate aldolase in serum, have been recorded initially on basal conditions, after 3 weeks of treatment (100 micrograms/day selenium or placebo) and again after 3 weeks of treatment, also on basal conditions, when crossing over the groups (between a free interval of 10 days). In another trial we registered these parameters on basal conditions and after two hours of hard training accompanied by a per oral administration of 150 micrograms selenium (respectively placebo). The results show significant changes under selenium treatment of the peroxides, G-6-PDH and light changes, not significant of the nonprotein--SH, changes which could suggest an antioxidant effect of this element.

  11. The Great White Guppy: Top Predator

    NASA Astrophysics Data System (ADS)

    Michalski, G. M.

    2011-12-01

    Nitrogen isotopes are often used to trace the trophic level of members of an ecosystem. As part of a stable isotope biogeochemistry and forensics course at Purdue University, students are introduced to this concept by analyzing nitrogen isotopes in sea food purchased from local grocery stores. There is a systematic increase in 15N/14N ratios going from kelp to clams/shrimp, to sardines, to tuna and finally to shark. These enrichments demonstrate how nitrogen is enriched in biomass as predators consume prey. Some of the highest nitrogen isotope enrichments observed, however, are in the common guppy. We investigated a number of aquarium fish foods and find they typically have high nitrogen isotope ratios because they are made form fish meal that is produced primarily from the remains of predator fish such as tuna. From, a isotope perspective, the guppy is the top of the food chain, more ferocious than even the Great White shark.

  12. Observation of single top-quark production.

    PubMed

    Abazov, V M; Abbott, B; Abolins, M; Acharya, B S; Adams, M; Adams, T; Aguilo, E; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Ancu, L S; Andeen, T; Anzelc, M S; Aoki, M; Arnoud, Y; Arov, M; Arthaud, M; Askew, A; Asman, B; Atramentov, O; Avila, C; BackusMayes, J; Badaud, F; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, P; Banerjee, S; Barberis, E; Barfuss, A-F; Bargassa, P; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Beale, S; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Bellavance, A; Benitez, J A; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Blazey, G; Blessing, S; Bloom, K; Boehnlein, A; Boline, D; Bolton, T A; Boos, E E; Borissov, G; Bose, T; Brandt, A; Brock, R; Brooijmans, G; Bross, A; Brown, D; Bu, X B; Buchanan, N J; Buchholz, D; Buehler, M; Buescher, V; Bunichev, V; Burdin, S; Burnett, T H; Buszello, C P; Calfayan, P; Calpas, B; Calvet, S; Cammin, J; Carrasco-Lizarraga, M A; Carrera, E; Carvalho, W; Casey, B C K; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K M; Chandra, A; Cheu, E; Cho, D K; Choi, S; Choudhary, B; Christofek, L; Christoudias, T; Cihangir, S; Claes, D; Clutter, J; Coadou, Y; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M-C; Crépé-Renaudin, S; Cuplov, V; Cutts, D; Cwiok, M; Das, A; Davies, G; De, K; de Jong, S J; De La Cruz-Burelo, E; DeVaughan, K; Déliot, F; Demarteau, M; Demina, R; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Dominguez, A; Dorland, T; Dubey, A; Dudko, L V; Duflot, L; Duggan, D; Duperrin, A; Dutt, S; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Eno, S; Ermolov, P; Escalier, M; Evans, H; Evdokimov, A; Evdokimov, V N; Ferapontov, A V; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fortner, M; Fox, H; Fu, S; Fuess, S; Gadfort, T; Galea, C F; Garcia-Bellido, A; Gavrilov, V; Gay, P; Geist, W; Geng, W; Gerber, C E; Gershtein, Y; Gillberg, D; Ginther, G; Gómez, B; Goussiou, A; Grannis, P D; Greder, S; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guo, F; Guo, J; Gutierrez, G; Gutierrez, P; Haas, A; Hadley, N J; Haefner, P; Hagopian, S; Haley, J; Hall, I; Hall, R E; Han, L; Harder, K; Harel, A; Hauptman, J M; Hays, J; Hebbeker, T; Hedin, D; Hegeman, J G; Heinson, A P; Heintz, U; Hensel, C; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hoang, T; Hobbs, J D; Hoeneisen, B; Hohlfeld, M; Hossain, S; Houben, P; Hu, Y; Hubacek, Z; Huske, N; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jakobs, K; Jamin, D; Jarvis, C; Jesik, R; Johns, K; Johnson, C; Johnson, M; Johnston, D; Jonckheere, A; Jonsson, P; Juste, A; Kajfasz, E; Karmanov, D; Kasper, P A; Katsanos, I; Kaushik, V; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y N; Khatidze, D; Kim, T J; Kirby, M H; Kirsch, M; Klima, B; Kohli, J M; Konrath, J-P; Kozelov, A V; Kraus, J; Kuhl, T; Kumar, A; Kupco, A; Kurca, T; Kuzmin, V A; Kvita, J; Lacroix, F; Lam, D; Lammers, S; Landsberg, G; Lebrun, P; Lee, W M; Leflat, A; Lellouch, J; Li, J; Li, L; Li, Q Z; Lietti, S M; Lim, J K; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Y; Liu, Z; Lobodenko, A; Lokajicek, M; Love, P; Lubatti, H J; Luna-Garcia, R; Lyon, A L; Maciel, A K A; Mackin, D; Mättig, P; Magerkurth, A; Mal, P K; Malbouisson, H B; Malik, S; Malyshev, V L; Maravin, Y; Martin, B; McCarthy, R; McGivern, C L; Meijer, M M; Melnitchouk, A; Mendoza, L; Mercadante, P G; Merkin, M; Merritt, K W; Meyer, A; Meyer, J; Mitrevski, J; Mommsen, R K; Mondal, N K; Moore, R W; Moulik, T; Muanza, G S; Mulhearn, M; Mundal, O; Mundim, L; Nagy, E; Naimuddin, M; Narain, M; Neal, H A; Negret, J P; Neustroev, P; Nilsen, H; Nogima, H; Novaes, S F; Nunnemann, T; O'Neil, D C; Obrant, G; Ochando, C; Onoprienko, D; Orduna, J; Oshima, N; Osman, N; Osta, J; Otec, R; Otero Y Garzón, G J; Owen, M; Padilla, M; Padley, P; Pangilinan, M; Parashar, N; Park, S-J; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Pawloski, G; Penning, B; Perfilov, M; Peters, K; Peters, Y; Pétroff, P; Piegaia, R; Piper, J; Pleier, M-A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pol, M-E; Polozov, P; Popov, A V; Potter, C; Prado da Silva, W L; Prosper, H B; Protopopescu, S; Qian, J; Quadt, A; Quinn, B; Rakitine, A; Rangel, M S; Ranjan, K; Ratoff, P N; Renkel, P; Rich, P; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F; Robinson, S; Rodrigues, R F; Rominsky, M; Royon, C; Rubinov, P; Ruchti, R; Safronov, G; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Sanghi, B; Savage, G; Sawyer, L; Scanlon, T; Schaile, D; Schamberger, R D; Scheglov, Y; Schellman, H; Schliephake, T; Schlobohm, S; Schwanenberger, C; Schwienhorst, R; Sekaric, J; Severini, H; Shabalina, E; Shamim, M; Shary, V; Shchukin, A A; Shivpuri, R K; Siccardi, V; Simak, V; Sirotenko, V; Skubic, P; Slattery, P; Smirnov, D; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Spurlock, B; Stark, J; Stolin, V; Stoyanova, D A; Strandberg, J; Strandberg, S; Strang, M A; Strauss, E; Strauss, M; Ströhmer, R; Strom, D; Stutte, L; Sumowidagdo, S; Svoisky, P; Takahashi, M; Tanasijczuk, A; Taylor, W; Tiller, B; Tissandier, F; Titov, M; Tokmenin, V V; Torchiani, I; Tsybychev, D; Tuchming, B; Tully, C; Tuts, P M; Unalan, R; Uvarov, L; Uvarov, S; Uzunyan, S; Vachon, B; van den Berg, P J; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vasilyev, I A; Verdier, P; Vertogradov, L S; Verzocchi, M; Vilanova, D; Vint, P; Vokac, P; Voutilainen, M; Wagner, R; Wahl, H D; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weber, G; Weber, M; Welty-Rieger, L; Wenger, A; Wetstein, M; White, A; Wicke, D; Williams, M R J; Wilson, G W; Wimpenny, S J; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Xu, C; Yacoob, S; Yamada, R; Yang, W-C; Yasuda, T; Yatsunenko, Y A; Ye, Z; Yin, H; Yip, K; Yoo, H D; Youn, S W; Yu, J; Zeitnitz, C; Zelitch, S; Zhao, T; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zivkovic, L; Zutshi, V; Zverev, E G

    2009-08-28

    We report observation of the electroweak production of single top quarks in pp[over ] collisions at sqrt[s]=1.96 TeV based on 2.3 fb(-1) of data collected by the D0 detector at the Fermilab Tevatron Collider. Using events containing an isolated electron or muon and missing transverse energy, together with jets originating from the fragmentation of b quarks, we measure a cross section of sigma(pp[over ]--> tb + X, tqb + X) = 3.94 + or - 0.88 pb. The probability to measure a cross section at this value or higher in the absence of signal is 2.5 x 10(-7), corresponding to a 5.0 standard deviation significance for the observation.

  13. Platts top 250 global energy company rankings

    SciTech Connect

    2006-11-15

    The third annual survey of global energy companies measures companies' financial performance using four metrics: asset worth, revenues, profits and return on invested capital. The following industry segments were analysed: coal and consumable fuel companies; diversified utilities; exploration and production; electric utilities; gas utilities; integrated oil and gas companies; refining and marketing; independent power producers and storage and transfer companies. Integrated oil and gas companies (IOGs) captured nine out of the top ten spots while IPPS struggled in 2005 as the sector on a whole lost money. The exploration and production segment showed financial stability while gas utilities saw their financials climb. The Exxon Mobile Corp. continued its reign of the number one spot.

  14. Radiative corrections to top-quark decay

    NASA Astrophysics Data System (ADS)

    Eilam, G.; Mendel, R. R.; Migneron, R.; Soni, A.

    1991-06-01

    We calculate all radiative corrections to one-loop order for the main decay of the top quark, t-->b+W, in the standard model, retaining exact dependence on all masses. For mt=150 GeV and MH=100 GeV we find a -2.9% (-6.9%) correction with a very weak dependence on the Higgs-boson mass, in renormalization schemes that use α, GF, and MZ (GF, MW, and MZ) as input parameters. Out of the above results, -8.5% is due to QCD. The mt and MH dependence is given up to 300 and 1000 GeV, respectively. The inadequacy of a leading mt calculation is pointed out.

  15. Who rises to the top? Early indicators.

    PubMed

    Kell, Harrison J; Lubinski, David; Benbow, Camilla P

    2013-05-01

    Youth identified before age 13 (N = 320) as having profound mathematical or verbal reasoning abilities (top 1 in 10,000) were tracked for nearly three decades. Their awards and creative accomplishments by age 38, in combination with specific details about their occupational responsibilities, illuminate the magnitude of their contribution and professional stature. Many have been entrusted with obligations and resources for making critical decisions about individual and organizational well-being. Their leadership positions in business, health care, law, the professoriate, and STEM (science, technology, engineering, and mathematics) suggest that many are outstanding creators of modern culture, constituting a precious human-capital resource. Identifying truly profound human potential, and forecasting differential development within such populations, requires assessing multiple cognitive abilities and using atypical measurement procedures. This study illustrates how ultimate criteria may be aggregated and longitudinally sequenced to validate such measures.

  16. Effects of top-dressing recycled broiler litter on litter production, litter characteristics, and nitrogen mass balance.

    PubMed

    Coufal, C D; Chavez, C; Niemeyer, P R; Carey, J B

    2006-03-01

    Top-dressing is a method of broiler litter management in which a thin layer of new, clean litter material is spread over the top of previously used litter prior to placement of a new flock. This fresh layer of bedding material increases the absorptive capacity of the litter and decreases litter caking. Although this practice has been widely used in the poultry industry for many years, no research has been conducted to quantify the effects the practice has on broiler performance, litter production rates, and nutrient content, or the ability of broiler litter to retain manure N and prevent volatilization. An experiment was conducted to quantify these parameters under simulated commercial conditions in a research facility. Nine consecutive flocks of broilers were reared on recycled broiler litter that had previously been used for 9 flocks. Control pens received no litter treatment whereas top-dressed pens received a thin layer of new rice hulls (1 to 2 cm) before the placement of each flock. Nitrogen loss was calculated using the mass balance method. Average broiler performance was not different between the top-dressed and control pens. Top-dressing of litter significantly (P < 0.05) reduced caked litter production compared with control pens in 6 of 9 flocks. However, average total litter production over all 9 flocks was not different between the 2 litter management strategies. In all flocks, litter N content was significantly reduced in top-dressed pens compared with control pens. As a result, litter C:N ratios were significantly higher for pens with top-dressed litter. Differences in N loss between the treatments were not consistent. Average N loss for all flocks was 10.61 and 11.92 g of N/kg of marketed broiler for control and top-dressed pens, respectively, or 20.1 and 22.5% of N inputs, respectively. Based on this experiment, top-dressing of recycled broiler litter would not be recommended as a strategy to reduce the volatilization of N from broiler rearing

  17. Measurement of the top quark mass

    SciTech Connect

    Varnes, Erich Ward

    1997-01-01

    This dissertation describes the measurement of the top quark mass mt using events recorded during a 125 pb-1 exposure of the D0 detector to √s=1.8 TeV $\\bar{p}$p collisions. Six events consistent with the hypothesis t$\\bar{t}$ → bW+, $\\bar{b}$W-t based on these relative solution likelihoods gives mt2+, $\\bar{b}$W- → b$\\bar{l}$v, $\\bar{b}$q$\\bar{q}$ , and this, in combination with an estimate on the likelihood that each event is top, yields mt = 173.3 ± 5.6 (stat.) ± 6.2 (syst.) GeV/c2t = 173.1 ± 5.2 (stat.) ± 5.7 (syst.) GeV/c2

  18. Jet Dipolarity: Top Tagging with Color Flow

    SciTech Connect

    Hook, Anson; Jankowiak, Martin; Wacker, Jay G.; /SLAC

    2011-08-12

    A new jet observable, dipolarity, is introduced that can distinguish whether a pair of subjets arises from a color singlet source. This observable is incorporated into the HEPTopTagger and is shown to improve discrimination between top jets and QCD jets for moderate to high p{sub T}. The impressive resolution of the ATLAS and CMS detectors means that a typical QCD jet at the LHC deposits energy in {Omicron}(10-100) calorimeter cells. Such fine-grained calorimetry allows for jets to be studied in much greater detail than previously, with sophisticated versions of current techniques making it possible to measure more than just the bulk properties of jets (e.g. event jet multiplicities or jet masses). One goal of the LHC is to employ these techniques to extend the amount of information available from each jet, allowing for a broader probe of the properties of QCD. The past several years have seen significant progress in developing such jet substructure techniques. A number of general purpose tools have been developed, including: (i) top-tagging algorithms designed for use at both lower and higher p{sub T} as well as (ii) jet grooming techniques such as filtering, pruning, and trimming, which are designed to improve jet mass resolution. Jet substructure techniques have also been studied in the context of specific particle searches, where they have been shown to substantially extend the reach of traditional search techniques in a wide variety of scenarios, including for example boosted Higgses, neutral spin-one resonances, searches for supersymmetry, and many others. Despite these many successes, however, there is every reason to expect that there remains room for refinement of jet substructure techniques.

  19. Boundary Layer Heights from CALIOP

    NASA Astrophysics Data System (ADS)

    Kuehn, R.; Ackerman, S. A.; Holz, R.; Roubert, L.

    2012-12-01

    This work is focused on the development of a planetary boundary layer (PBL) height retrieval algorithm for CALIOP and validation studies. Our current approach uses a wavelet covariance transform analysis technique to find the top of the boundary layer. We use the methodology similar to that found in Davis et. al. 2000, ours has been developed to work with the lower SNR data provided by CALIOP, and is intended to work autonomously. Concurrently developed with the CALIOP algorithm we will show results from a PBL height retrieval algorithm from profiles of potential temperature, these are derived from Aircraft Meteorological DAta Relay (AMDAR) observations. Results from 5 years of collocated AMDAR - CALIOP retrievals near O'Hare airport demonstrate good agreement between the CALIOP - AMDAR retrievals. In addition, because we are able to make daily retrievals from the AMDAR measurements, we are able to observe the seasonal and annual variation in the PBL height at airports that have sufficient instrumented-aircraft traffic. Also, a comparison has been done between the CALIOP retrievals and the NASA Langley airborne High Spectral Resolution Lidar (HSRL) PBL height retrievals acquired during the GoMACCS experiment. Results of this comparison, like the AMDAR comparison are favorable. Our current work also involves the analysis and verification of the CALIOP PBL height retrieval from the 6 year CALIOP global data set. Results from this analysis will also be presented.

  20. Measurements of top quark properties in top pair production and decay at the LHC using the CMS detector

    DOE PAGES

    Jindariani, Sergo

    2016-05-31

    Measurements are presented of the properties of top quarks in pair production and decay from proton-proton collisions at the LHC. The data were collected at centre-of-mass energies of 7 and 8 TeV by the CMS experiment during the years 2011 and 2012. The top quark-antiquark charge asymmetry is measured using the difference of the absolute rapidities of the reconstructed top and anti-top kinematics, as well as from distributions of the top quark decay products. The measurements are performed in the decay channels of the tt¯ pair into both one and two leptons in the final state. The polarization of topmore » quarks and top pair spin correlations are measured from the angular distributions of top quark decay products. The W-boson helicity fractions and angular asymmetries are extracted and limits on anomalous contributions to the Wtb vertex are determined. The flavor content in top-quark pair events is measured using the fraction of top quarks decaying into a W-boson and a b -quark relative to all top quark decays, R=B(t→Wb)/B(t→Wq) , and the result is used to determine the CKM matrix element Vtb as well as the width of the top quark resonance. Finally, all of the results are found to be in good agreement with standard model predictions.« less