WorldWideScience

Sample records for bulk density

  1. Synthesizing Bulk Density for Soils with Abundant Rock Fragments

    Science.gov (United States)

    Vincent, K. R.; Chadwick, O. A.

    1994-01-01

    Bulk density is a fundamental soil property that is difficult to determine for gravelly to extremely gravelly soils because results vary significantly with sample volume. For such coarse soils, the representative volume (for whole-soil bulk density) should be large, but guidelines for selecting an appropriate sample volume do not exist.

  2. Thermal neutron diffusion parameters for media of variable bulk density

    International Nuclear Information System (INIS)

    Thermal neutron diffusion parameters (the macroscopic cross sections, and the diffusion cooling coefficients) for a given medium are dependent on the mass density. Therefore, thermal neutron experiments are influenced by the density of samples used. In the case of measurement series with bulk materials it is difficult to keep the same bulk density for all samples of the material. The classic thermal neutron pulsed experiment is considered in the paper. A method is shown to eliminate the influence of the variable bulk density on the results. A concept of the generalised decay constant and geometric buckling, and of the so-called density-removed neutron parameters, is used. Preliminary results of the Monte Carlo computer simulations of experimental series for polyethylene spherical samples of different porosity are presented. (author)

  3. EFFECTIVE POROSITY IMPLIES EFFECTIVE BULK DENSITY IN SORBING SOLUTE TRANSPORT

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G.

    2012-02-27

    The concept of an effective porosity is widely used in solute transport modeling to account for the presence of a fraction of the medium that effectively does not influence solute migration, apart from taking up space. This non-participating volume or ineffective porosity plays the same role as the gas phase in single-phase liquid unsaturated transport: it increases pore velocity, which is useful towards reproducing observed solute travel times. The prevalent use of the effective porosity concept is reflected by its prominent inclusion in popular texts, e.g., de Marsily (1986), Fetter (1988, 1993) and Zheng and Bennett (2002). The purpose of this commentary is to point out that proper application of the concept for sorbing solutes requires more than simply reducing porosity while leaving other material properties unchanged. More specifically, effective porosity implies the corresponding need for an effective bulk density in a conventional single-porosity model. The reason is that the designated non-participating volume is composed of both solid and fluid phases, both of which must be neglected for consistency. Said another way, if solute does not enter the ineffective porosity then it also cannot contact the adjoining solid. Conceptually neglecting the fluid portion of the non-participating volume leads to a lower (effective) porosity. Likewise, discarding the solid portion of the non-participating volume inherently leads to a lower or effective bulk density. In the author's experience, practitioners virtually never adjust bulk density when adopting the effective porosity approach.

  4. Bulk Density Adjustment of Resin-Based Equivalent Material for Geomechanical Model Test

    OpenAIRE

    Pengxian Fan; Haozhe Xing; Linjian Ma; Kaifeng Jiang; Mingyang Wang; Zechen Yan; Xiang Fang

    2015-01-01

    An equivalent material is of significance to the simulation of prototype rock in geomechanical model test. Researchers attempt to ensure that the bulk density of equivalent material is equal to that of prototype rock. In this work, barite sand was used to increase the bulk density of a resin-based equivalent material. The variation law of the bulk density was revealed in the simulation of a prototype rock of a different bulk density. Over 300 specimens were made for uniaxial compression test....

  5. Phobos' Low Bulk Density: Evidence Against a Capture Origin?

    Science.gov (United States)

    Dalle Ore, C.; Pajola, M.; Lazzarin, M.; Roush, T. L.; Cruikshank, D. P.; Pendleton, Y. J.; Carli, C.; Bertini, I.; Magrin, S.; La Forgia, F.; Barbieri, C.

    2014-12-01

    Phobos' low density of 1.876 ± 0.02 g/cm3 (Andert et al., 2010, Witasse et al., 2013, Paetzold et al., 2013) supports its formation from a disk of debris (Peale 2007). The disk would either be a remnant of the formation of Mars (Safronov et al., 1986) or the result of a collision between Mars and a large body (Craddock 1994, 2011; Singer 2007). Within this scenario a large interior porosity would be responsible for the low density of the re-accreted material forming Phobos. Thermal emission spectra of Phobos suggest an ultramafic composition with the presence of phyllosilicates and feldspathoids in some regions (Giuranna et al., 2011), consistent with Phobos' in situ formation (Giuranna et al., 2011). However, the 0.3-4.0 μm surface spectra taken from multiple areas of the body in more than 43 years of observations (Duxbury et al., 2013), show physical characteristics similar to low-albedo asteroids such as C-type (Masursky et al., 1972, Pang et al., 1980) or D-type (Murchie 1999, Rivkin et al., 2002, Lynch et al., 2007, Pajola et al., 2012). They argue in favor of an asteroidal capture scenario that could be explained by binary asteroid dissociation (Landis 2009) or by collisional capture in the Martian orbital region (Pajola et al., 2012). Finally recent work by Schmedemann et al., (2014) indicates Phobos' surface to be ~ 4.3 - 3.7 Ga, dating back to a period where there was an intensification in the number of impactors in the inner Solar System (Gomes et al., 2005), and supporting both the in-situ and the capture scenario. Pajola et al. (2013) match the surface reflectance of Phobos from 0.4 to 4.0 μm with a mineralogical model composed of a mixture of Tagish Lake meteorite (TL) and Pyroxene Glass (PM80). Based on the published model, we adopted the weighted TL and PM80 densities to investigate if the low bulk density of Phobos could conform with these components reconciling both inner properties and surface spectra. While the TL density is available from

  6. Superfluid density of bulk CaC 6

    Science.gov (United States)

    Lamura, G.; Aurino, M.; Cifariello, G.; Di Gennaro, E.; Andreone, A.; Emery, N.; Hérold, C.; Marêché, J.-F.; Lagrange, P.

    2007-09-01

    The recent discovery of superconductivity at 11.5 K in the graphite intercalation compound (GIC) CaC6 has opened new perspectives in the physics of graphite. One of the main open questions for superconducting GICs is related to the nature of the pairing mechanism, since the possibility of an unconventional, excitonic or plasmonic, origin of superconductivity has also been invoked as an alternative to a simple electron-phonon interaction. To better understand the origin of pairing mechanism in these compounds, a first step is to determine the symmetry of the superconducting gap function and the nature of the elementary excitations. To this aim, we have performed the first high-resolution measurement of the in-plane magnetic penetration depth, λab(T), in a c-axis oriented polycrystalline CaC6 bulk sample using a high-resolution mutual inductance technique. A clear exponential behavior of λab(T) has been observed at low temperatures, strongly suggesting isotropic s-wave pairing. Data fit using the standard BCS theory yields λab(0) = (720 ± 80) Å and Δ(0) = (1.79 ± 0.08) meV. The ratio 2Δ(0)/kBTC = (3.6 ± 0.2) gives therefore indication for a conventional weakly coupled superconductor. By using these results as fixed parameters, a BCS calculation on the superfluid density in the overall temperature range shows that the sample under test lies in the local dirty limit.

  7. Superfluid density of bulk CaC{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Lamura, G. [CNR-INFM Coherentia and Department of Physics, University of Naples ' Federico II' , 80125 Naples (Italy)], E-mail: lamura@na.infn.it; Aurino, M.; Cifariello, G.; Di Gennaro, E.; Andreone, A. [CNISM and Department of Physics, University of Naples ' Federico II' , 80125 Naples (Italy); Emery, N.; Herold, C.; Mareche, J.-F.; Lagrange, P. [Laboratoire de Chimie du Solide Mineral-UMR 7555, Universite Henri Poincare Nancy I, B.P. 239, 54506 Vandoeuvre-les-Nancy Cedex (France)

    2007-09-01

    The recent discovery of superconductivity at 11.5 K in the graphite intercalation compound (GIC) CaC{sub 6} has opened new perspectives in the physics of graphite. One of the main open questions for superconducting GICs is related to the nature of the pairing mechanism, since the possibility of an unconventional, excitonic or plasmonic, origin of superconductivity has also been invoked as an alternative to a simple electron-phonon interaction. To better understand the origin of pairing mechanism in these compounds, a first step is to determine the symmetry of the superconducting gap function and the nature of the elementary excitations. To this aim, we have performed the first high-resolution measurement of the in-plane magnetic penetration depth, {lambda}{sub ab}(T), in a c-axis oriented polycrystalline CaC{sub 6} bulk sample using a high-resolution mutual inductance technique. A clear exponential behavior of {lambda}{sub ab}(T) has been observed at low temperatures, strongly suggesting isotropic s-wave pairing. Data fit using the standard BCS theory yields {lambda}{sub ab}(0) = (720 {+-} 80) A and {delta}(0) = (1.79 {+-} 0.08) meV. The ratio 2{delta}(0)/k{sub B}T{sub C} = (3.6 {+-} 0.2) gives therefore indication for a conventional weakly coupled superconductor. By using these results as fixed parameters, a BCS calculation on the superfluid density in the overall temperature range shows that the sample under test lies in the local dirty limit.

  8. The determination of bulk (apparent) density of plant fibres by density method

    International Nuclear Information System (INIS)

    The absolute density of plant fibres excludes all pores and lumen and therefore is a measure of the solid matter of the fibres. On the other hand the bulk density, which is being discussed here, includes all the solid matter and the pores of the fibres. In this work, the apparent density of the fibre was measured by using the Archimedes principle, which involves the immersion of a known weight of fibre into a solvent of lower density than the fibre. Toluene with a density of about 860 kg/m3 was chosen as a solvent. A tuft of fibre was weighed and recorded as Wfa. The fibre was then immersed in toluene, which wetted the fibre, and made to rest on the weighing pan submerged in the solvent and the weight of the immersed fibre was recorded as Wfs. The apparent density was then calculated using the equation. All the measurements were taken at room temperature. The fibre samples were not oven dried prior to measurement. (Author)

  9. Bulk Density Adjustment of Resin-Based Equivalent Material for Geomechanical Model Test

    Directory of Open Access Journals (Sweden)

    Pengxian Fan

    2015-01-01

    Full Text Available An equivalent material is of significance to the simulation of prototype rock in geomechanical model test. Researchers attempt to ensure that the bulk density of equivalent material is equal to that of prototype rock. In this work, barite sand was used to increase the bulk density of a resin-based equivalent material. The variation law of the bulk density was revealed in the simulation of a prototype rock of a different bulk density. Over 300 specimens were made for uniaxial compression test. Test results indicated that the substitution of quartz sand by barite sand had no apparent influence on the uniaxial compressive strength and elastic modulus of the specimens but can increase the bulk density, according to the proportional coarse aggregate content. An ideal linearity was found in the relationship between the barite sand substitution ratio and the bulk density. The relationship between the bulk density and the usage of coarse aggregate and barite sand was also presented. The test results provided an insight into the bulk density adjustment of resin-based equivalent materials.

  10. STUDY ON THE BULK DENSITY OF HIGH CONSISTENCY PULP AND ENGINEERING APPLICATION IN THE BLEACHING TOWER

    Directory of Open Access Journals (Sweden)

    Ke-Fu Chen

    2011-02-01

    Full Text Available From experimental simulation of the process of high consistency pulp moving in a bleaching tower, the aerated bulk density and packed bulk density were measured and studied by using a self-made experimental system. The scattered experimental data – pressure p, and bulk density difference, which was between packed bulk density and aerated bulk density (ρ-ρ0 – were fitted by using Matlab software, and some good-fitting regression curves and equations were obtained. The results showed there was a break point W in the regression curves; within the range of pressure between zero and W the relationship between (ρ-ρ0 and p was a linear function, while for pressure between W and 70000 the relationship was a power function. To effectively meet with the bleaching response for the different kinds and different consistencies of pulp in the tower, by using the fitting regression equations combined with the expressions of average bulk density and pressure in the tower caused by gravity-driven pulp, two equations for average packed density ρa were deduced with the aim of deciding the maximum volume value of the tower, in agreement with the sizes of the towers presently used by major companies.

  11. Bulk density estimation using a 3-dimensional image acquisition and analysis system

    Directory of Open Access Journals (Sweden)

    Heyduk Adam

    2016-01-01

    Full Text Available The paper presents a concept of dynamic bulk density estimation of a particulate matter stream using a 3-d image analysis system and a conveyor belt scale. A method of image acquisition should be adjusted to the type of scale. The paper presents some laboratory results of static bulk density measurements using the MS Kinect time-of-flight camera and OpenCV/Matlab software. Measurements were made for several different size classes.

  12. Direct measurement and prediction of bulk density on alluvial soils of central Chile

    OpenAIRE

    Manuel Casanova; Elizabeth Tapia; Oscar Seguel; Osvaldo Salazar

    2016-01-01

    The significance of soil bulk density (ρ) as a key indicator of soil quality was examined in this study. Bulk density values obtained by direct methods (clod, cylinder, and excavation) with three sample sizes (small, medium, and large) were compared with those obtained by 10 published pedotransfer functions (PTFs) for two alluvial soils (a massive fine-textured Fluventic Haploxeroll and an aggregated, coarse-textured Fluventic Haploxerept) of central Chile. With the exception of small cylinde...

  13. Pedotransfer functions for Irish soils - estimation of bulk density (ρb) per horizon type

    Science.gov (United States)

    Reidy, B.; Simo, I.; Sills, P.; Creamer, R. E.

    2016-01-01

    Soil bulk density is a key property in defining soil characteristics. It describes the packing structure of the soil and is also essential for the measurement of soil carbon stock and nutrient assessment. In many older surveys this property was neglected and in many modern surveys this property is omitted due to cost both in laboratory and labour and in cases where the core method cannot be applied. To overcome these oversights pedotransfer functions are applied using other known soil properties to estimate bulk density. Pedotransfer functions have been derived from large international data sets across many studies, with their own inherent biases, many ignoring horizonation and depth variances. Initially pedotransfer functions from the literature were used to predict different horizon type bulk densities using local known bulk density data sets. Then the best performing of the pedotransfer functions were selected to recalibrate and then were validated again using the known data. The predicted co-efficient of determination was 0.5 or greater in 12 of the 17 horizon types studied. These new equations allowed gap filling where bulk density data were missing in part or whole soil profiles. This then allowed the development of an indicative soil bulk density map for Ireland at 0-30 and 30-50 cm horizon depths. In general the horizons with the largest known data sets had the best predictions, using the recalibrated and validated pedotransfer functions.

  14. Quark mass density- and temperature- dependent model for bulk strange quark matter

    OpenAIRE

    al, Yun Zhang et.

    2002-01-01

    It is shown that the quark mass density-dependent model can not be used to explain the process of the quark deconfinement phase transition because the quark confinement is permanent in this model. A quark mass density- and temperature-dependent model in which the quark confinement is impermanent has been suggested. We argue that the vacuum energy density B is a function of temperature. The dynamical and thermodynamical properties of bulk strange quark matter for quark mass density- and temper...

  15. PEDO-TRANSFER FUNCTIONS FOR ESTIMATING SOIL BULK DENSITY IN CENTRAL AMAZONIA

    Directory of Open Access Journals (Sweden)

    Henrique Seixas Barros

    2015-04-01

    Full Text Available Under field conditions in the Amazon forest, soil bulk density is difficult to measure. Rigorous methodological criteria must be applied to obtain reliable inventories of C stocks and soil nutrients, making this process expensive and sometimes unfeasible. This study aimed to generate models to estimate soil bulk density based on parameters that can be easily and reliably measured in the field and that are available in many soil-related inventories. Stepwise regression models to predict bulk density were developed using data on soil C content, clay content and pH in water from 140 permanent plots in terra firme (upland forests near Manaus, Amazonas State, Brazil. The model results were interpreted according to the coefficient of determination (R2 and Akaike information criterion (AIC and were validated with a dataset consisting of 125 plots different from those used to generate the models. The model with best performance in estimating soil bulk density under the conditions of this study included clay content and pH in water as independent variables and had R2 = 0.73 and AIC = -250.29. The performance of this model for predicting soil density was compared with that of models from the literature. The results showed that the locally calibrated equation was the most accurate for estimating soil bulk density for upland forests in the Manaus region.

  16. The effects of forward speed and depth of conservation tillage on soil bulk density

    Directory of Open Access Journals (Sweden)

    A Mahmoudi

    2015-09-01

    Full Text Available Introduction: In recent years, production techniques and equipment have been developed for conservation of tillage systems that have been adopted by many farmers. With proper management, overall yield averages for conventional and reduced tillage systems are nearly identical. Sometimes, field operations can be combined by connecting two or more implements. Combined operations reduce both fuel consumption, and time and labor requirements by eliminating at least one individual trip over the field. Light tillage, spraying, or fertilizing operations can be combined with either primary or secondary tillage or planting operations. Tillage helps seed growth and germination through providing appropriate conditions for soil to absorb sufficient temperature and humidity. Moreover, it helps easier development of root through reducing soil penetration resistance. Tillage is a time-consuming and expensive procedure. With the application of agricultural operations, we can save substantial amounts of fuel, time and energy consumption. Conservation tillage loosens the soil without turning, but by remaining the plant left overs, stems and roots. Bulk density reflects the soil’s ability to function for structural support, water and solute movement, and soil aeration. Bulk densities above thresholds indicate impaired function. Bulk density is also used to convert between weight and volume of soil. It is used to express soil physical, chemical and biological measurements on a volumetric basis for soil quality assessment and comparisons between management systems. This increases the validity of comparisons by removing the error associated with differences in soil density at the time of sampling. The aim of conservation tillage is to fix the soil structure. This investigation was carried out considering the advantages of conservation tillage and less scientific research works on imported conservation tillage devices and those which are made inside the country

  17. Links between matrix bulk density, macropore characteristics and hydraulic behavior of soils

    DEFF Research Database (Denmark)

    Katuwal, Sheela; Møldrup, Per; Lamandé, Mathieu;

    2013-01-01

    The relationship of soil bulk density with the hydraulic behavior of soil and the role of macropores in preferential flow and transport has been extensively studied in literatures. Yet, the influence of soil structural heterogeneity as simultaneous variation of bulk density and macropore characte......The relationship of soil bulk density with the hydraulic behavior of soil and the role of macropores in preferential flow and transport has been extensively studied in literatures. Yet, the influence of soil structural heterogeneity as simultaneous variation of bulk density and macropore...... characteristics on soil hydraulic functions has rarely been studied. With the objective of studying the links between these parameters we quantified macropore characteristics of intact soil columns (19 cm diameter x 20 cm high) from two agricultural field sites (Silstrup and Faardrup) in Denmark using coarse....... However, in Faardrup soils macroporosity and matrix bulk density were weakly correlated. Though macroporosity and interconnectivity of macropores could explain some variation in the hydraulic behavior of a few samples from Faardrup, the preferential flow behavior was observed to be primarily influenced...

  18. A Method for Determining Bulk Density, Material Density, and Porosity of Melter Feed During Nuclear Waste Vitrification

    Energy Technology Data Exchange (ETDEWEB)

    Hilliard, Zachary J.; Hrma, Pavel R.

    2016-01-31

    Abstract Glass making efficiency largely depends on heat transfer to reacting glass batch (melter feed), which in turn is influenced by the bulk density (ρb) and porosity (Φ) as functions of temperature (T). Neither b(T) nor Φ(T) functions are readily accessible to direct measurement, but they can be determined based on monitoring the profile area of heated glass batch pellets and material density of batches quenched at various stages of conversion via pycnometry. For the determination of Φb, the bulk volume must be calculated as a function of temperature. This is done via a program constructed in MATLAB which takes an image of a pellet profile at a given temperature and calculates the volume of said pellet. The quenched density measured by pycnometry must be converted to the density at heat treatment temperature. This is done by taking into account the volume change due to thermal expansion/contraction.

  19. Bulk density and water tensions in the soil on corn root production

    OpenAIRE

    João A. S. Nunes; Edna M. Bonfim-Silva; Tonny J. A. da Silva

    2016-01-01

    ABSTRACT Inadequate management of soil and water can cause changes in soil physical characteristics, resulting in lower root development. Thus the objective of the present study was to evaluate the dry matter production of corn roots under combinations of levels of bulk density and water tension in the soil. The experiment was conducted in a greenhouse in a randomized block design, based on a modified central composite design of a 52 fractional factorial scheme, of combinations of bulk densit...

  20. Specification of Density Functional Approximation by Radial Distribution Function of Bulk Fluid

    Institute of Scientific and Technical Information of China (English)

    ZHOUShi-Qi

    2002-01-01

    A systematic methodology is proposed to deal with the weighted density approximation version of classical density functional theory by employing the knowledge of radial distribution function of bulk fluid.The present methodology results from the concept of universality of the free energy density functional combined with the test particle method.It is shown that the new method is very accurate for the predictions of density distribution of a hard sphere fluid at different confining geometries.The physical foundation of the present methodology is also applied to the quantum density functional theory.

  1. Bounds on the local energy density of holographic CFTs from bulk geometry

    Science.gov (United States)

    Fischetti, Sebastian; Hickling, Andrew; Wiseman, Toby

    2016-11-01

    The stress tensor is a basic local operator in any field theory; in the context of AdS/CFT, it is the operator which is dual to the bulk geometry itself. Here we exploit this feature by using the bulk geometry to place constraints on the local energy density in static states of holographic (2+1)-dimensional CFTs living on a closed (but otherwise generally curved) spatial geometry. We allow for the presence of a marginal scalar deformation, dual to a massless scalar field in the bulk. For certain vacuum states in which the bulk geometry is well-behaved at zero temperature, we find that the bulk equations of motion imply that the local energy density integrated over specific boundary domains is negative. In the absence of scalar deformations, we use the inverse mean curvature flow to show that if the CFT spatial geometry has spherical topology but non-constant curvature, the local energy density must be positive somewhere. This result extends to other topologies, but only for certain types of vacuum; in particular, for a generic toroidal boundary, the vacuum’s bulk dual must be the zero-temperature limit of a toroidal black hole.

  2. Vibration-Induced Conductivity Fluctuation Measurement for Soil Bulk Density Analysis

    CERN Document Server

    Kishne, Andrea Sz; Chang, Hung-Chih; Kish, Laszlo B

    2007-01-01

    Soil bulk density affects water storage, water and nutrient movement, and plant root activity in the soil profile. Its measurement is difficult in field conditions. Vibration-induced conductivity fluctuation was investigated to quantify soil bulk density with possible field applications in the future. The AC electrical conductivity of soil was measured using a pair of blade-like electrodes while exposing the soil to periodic vibration. The blades were positioned longitudinally and transversally to the direction of the induced vibration to enable the calculation of a normalized index. The normalized index was expected to provide data independent from the vibration strength and to reduce the effect of soil salinity and water content. The experiment was conducted on natural and salinized fine sand at two moisture conditions and four bulk densities. The blade-shaped electrodes improved electrode-soil contact compared to cylindrical electrodes, and thereby, reduced measurement noise. Simulations on a simplified re...

  3. An Approach to Calculate Mineralś Bulk Moduli KS from Chemical Composition and Density ρ

    Science.gov (United States)

    Breuer, S.; Schilling, F. R.; Mueller, B.; Drüppel, K.

    2015-12-01

    The elastic properties of minerals are fundamental parameters for technical and geotechnical applications and an important research topic towards a better understanding of the Eart&hacute;s interior. Published elastic properties, chemical composition, and density data of 86 minerals (total of 258 data including properties of minerals at various p, T conditions) were collected into a database. It was used to test different hypotheses about relationships between these properties (e.g. water content in minerals and their Poisson's ratio). Furthermore, a scheme to model the average elastic properties, i.e. the bulk modulus KS, based on mineral density and composition was developed. Birc&hacute;s law, a linearity between density ρ and wave velocity (e.g. vp.), is frequently used in seismic and seismology to derive density of the Eart&hacute;s interior from seismic velocities. Applying the compiled mineral data contradicts the use of a simple velocity-density relation (e.g. Gardneŕs relation, 1974). The presented model-approach to estimate the mineralś bulk moduli Ks (as Voigt-Reuss-Hill average) is based on the idea of pressure-temperature (p-T) dependent ionś bulk moduli. Using a multi-exponential regression to ascertain the ionś bulk moduli and by applying an exponential scaling with density ρ, their bulk moduli could be modelled. As a result, > 88 % of the 258 bulk moduli data are predicted with an uncertainty of < 20 % compared to published values. Compared to other models (e.g. Anderson et al. 1970 and Anderson & Nafe 1965), the here presented approach to model the bulk moduli only requires the density ρ and chemical composition of the mineral and is not limited to a specific group of minerals, composition, or structure. In addition to this, by using the pressure and temperature dependent density ρ(p, T), it is possible to predict bulk moduli for varying p-T conditions. References:Gardner, G.H.F, Gardner, L.W. and Gregory, A.R. (1974). Geophysics, 39, No. 6

  4. Power Spectral Density of Fluctuations of Bulk and Thermal Speeds in the Solar Wind

    Science.gov (United States)

    Šafránková, J.; Němeček, Z.; Němec, F.; Přech, L.; Chen, C. H. K.; Zastenker, G. N.

    2016-07-01

    This paper analyzes solar wind power spectra of bulk and thermal speed fluctuations that are computed with a time resolution of 32 ms in the frequency range of 0.001–2 Hz. The analysis uses measurements of the Bright Monitor of the Solar Wind on board the Spektr-R spacecraft that are limited to 570 km s‑1 bulk speed. The statistics, based on more than 42,000 individual spectra, show that: (1) the spectra of bulk and thermal speeds can be fitted by two power-law segments; (2) despite their large variations, the parameters characterizing frequency spectrum fits computed on each particular time interval are very similar for both quantities; (3) the median slopes of the bulk and thermal speeds of the segment attributed to the MHD scale are ‑1.43 and ‑1.38, respectively, whereas they are ‑3.08 and ‑2.43 in the kinetic range; (4) the kinetic range slopes of bulk and thermal speed spectra become equal when either the ion density or magnetic field strength are high; (5) the break between MHD and kinetic scales seems to be controlled by the ion β parameter; (6) the best scaling parameter for bulk and thermal speed variations is a sum of the inertial length and proton thermal gyroradius; and (7) the above conclusions can be applied to the density variations if the background magnetic field is very low.

  5. Specification of Density Functional Approximation by Radial Distribution Function of Bulk Fluid

    Institute of Scientific and Technical Information of China (English)

    ZHOU Shi-Qi

    2002-01-01

    A systematic methodology is proposed to deal with the weighted density approximation version of clas-sical density functional theory by employing the knowledge of radial distribution function of bulk fluid. The presentmethodology results from the concept of universality of the free energy density functional combined with the test particlemethod. It is shown that the new method is very accurate for the predictions of density distribution ofa hard sphere fluidat different confining geometries. The physical foundation of the present methodology is also applied to the quantumdensity functional theory.

  6. Bounds on the local energy density of holographic CFTs from bulk geometry

    CERN Document Server

    Fischetti, Sebastian; Wiseman, Toby

    2016-01-01

    The stress tensor is a basic local operator in any field theory; in the context of AdS/CFT, it is the operator which is dual to the bulk geometry itself. Here we exploit this feature by using the bulk geometry to place constraints on the local energy density in static states of holographic $(2+1)$-dimensional CFTs living on a closed (but otherwise generally curved) spatial geometry. We allow for the presence of a marginal scalar deformation, dual to a massless scalar field in the bulk. For certain vacuum states in which the bulk geometry is well-behaved at zero temperature, we find that the bulk equations of motion imply that the local energy density integrated over specific boundary domains is negative. In the absence of scalar deformations, we use the inverse mean curvature flow to show that if the CFT spatial geometry has spherical topology but non-constant curvature, the local energy density must be positive somewhere. This result extends to other topologies, but only for certain types of vacuum; in parti...

  7. The Effect of Bulk Density on Emission Behavior of Soil at Microwave Frequencies

    Directory of Open Access Journals (Sweden)

    V. K. Gupta

    2011-01-01

    Full Text Available Dielectric constant and dielectric loss (ε′ and ε″ of different soil samples with bulk densities varying from 1.3 to 2.0 gm/cm3 are determined at a single microwave frequency 9.78 GHz and at temperature 37.0°C. Different bulk densities of same soil are achieved by filling the wave guide cell with an equal volume but a different mass of soil. Further, ε′ and ε″ of these soil samples are also estimated by semiempirical model and compared with the experimental results. The values of ε′ and ε″ increase as bulk density of the soil increases. In view of microwave remote sensing, the Fresnel reflectivity of soil is computed from the knowledge of the complex dielectric constant and the surface boundary condition. Using Kirchhoff’s reciprocity theorem the microwave emissivity is estimated from Fresnel reflectivity of the surface. It is observed that the microwave emission from the soil surface inhibits as bulk density of soil increases. Further, the roughness of soil surface has been taken into consideration in the emissivity computation and observed that the emissivity increases with increasing roughness of the soil surface.

  8. Microwave sensing of moisture content and bulk density in flowing grain

    Science.gov (United States)

    Moisture content and bulk density were determined from measurement of the dielectric properties of flowing wheat kernels at a single microwave frequency (5.8 GHz). The measuring system consisted of two high-gain microwave patch antennas mounted on opposite sides of rectangular chute and connected to...

  9. Microwave Nondestructive Sensing of Moisture Content in Shelled Peanuts Independent of Bulk Density with Temperature Compensation

    Science.gov (United States)

    Dielectric methods for rapid and nondestructive sensing of moisture content in shelled peanuts from free-space measurement of attenuation and phase shift, and their corresponding dielectric properties at 10 GHz, are presented. These methods provide moisture content independent of bulk density and c...

  10. Non-destructive image analysis of soil surface porosity and bulk density dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Pires, L.F., E-mail: lfpires@uepg.b [Laboratory of Soil Physics and Environmental Sciences, State University of Ponta Grossa, UEPG, C.E.P. 84.030-900, Ponta Grossa, PR (Brazil); Cassaro, F.A.M. [Laboratory of Soil Physics and Environmental Sciences, State University of Ponta Grossa, UEPG, C.E.P. 84.030-900, Ponta Grossa, PR (Brazil); Bacchi, O.O.S.; Reichardt, K. [Laboratory of Soil Physics, Center for Nuclear Energy in Agriculture, USP/CENA, C.P. 96, C.E.P. 13.400-970, Piracicaba, SP (Brazil)

    2011-04-15

    A gamma-ray computed tomography (CT) scanner was used to evaluate changes in the structure of clayey soil samples with surface compaction submitted to wetting and drying (W-D) cycles. The obtained results indicate that W-D cycles promoted an increasing of about 10% in soil porosity with a decreasing of about 6% in soil bulk density of this compacted region. With the use of the CT it was also possible to define the thickness of the compacted region that in our case was of about 8.19 mm. This last information is very important, for instance, to estimate hydraulic parameters in infiltration models. Finally, CT analysis showed that the compacted region remained at the surface samples, even after the application of the W-D cycles. -- Research highlights: {yields} Gamma-ray tomography allowed non-destructive analysis of soil bulk density and porosity changes. {yields} Soil porosity increased about 10% with the wetting and drying cycles. {yields} Soil bulk density in the compacted region decreased about 6% with the wetting and drying cycles. {yields} Detailed bulk density and porosity analysis changes were obtained for layers of 1.17 mm.

  11. Bulk Density of Comet 9P/Tempel 1 Based on Orbital and Rotational Nongravitational Effects

    Science.gov (United States)

    Samarasinha, Nalin H.; Belton, M.; Farnham, T.; Gutierrez, P.; Mueller, B.; Chesley, S.

    2009-09-01

    The accurate determination of bulk densities of cometary nuclei provides a strong indicator of their interior structure and will furnish insights into the conditions in the early solar system. The primary technique to determine cometary bulk densities is by correlating the secular orbital changes of the comet with the corresponding forces due to outgassing. However, significant uncertainties persist in these determinations as the accurate assessment of forces due to outgassing is difficult. Davidsson et al. (2007) derived a bulk density of 200-700 kg m-3 for comet 9P/Tempel 1 based on the orbital nongravitational forces. Richardson and colleagues (e.g,, Richardson et al. 2007) independently determined a density of 200-1000 kg m-3 for comet 9P/Tempel 1 based on the analysis of the ejecta fallback caused by the impactor of the Deep Impact mission. These density determinations based on widely different techniques yield consistent results; however, the allowed density range is relatively large. A simultaneous modeling of orbital and rotational changes in 9P/Tempel 1 is expected to yield more constraining results for the bulk density. Accurate determinations of the rotational changes (Belton et al. 2009) and the localized activity (cf. Farnham et al. 2007, Feaga et al. 2007, Schleicher 2006) of comet 9P/Tempel 1 allow us to simultaneously model the orbital and rotational changes caused by outgassing in a self-consistent manner. Initial results from this study will be presented at the meeting. We thank NASA Outer Planets Research Program. References: Belton, M.J.S. et al. 2009. Icarus, in preparation. Davidsson, B.J.R. et al. 2007, Icarus, 187, 306-320. Farnham, T.L. et al. 2007. Icarus, 187, 26-40. Feaga, L.M. et al. 2007. Icarus, 190, 345-356. Richardson, J.E. et al. 2007. Icarus, 190, 357-390. Schleicher D.G. 2006. Icarus, 181, 442-457.

  12. Bulk viscosity of strange quark matter in density dependent quark mass model

    Indian Academy of Sciences (India)

    J D Anand; N Chandrika Devi; V K Gupta; S Singh

    2000-05-01

    We have studied the bulk viscosity of strange quark matter in the density dependent quark mass model (DDQM) and compared results with calculations done earlier in the MIT bag model where , masses were neglected and first order interactions were taken into account. We find that at low temperatures and high relative perturbations, the bulk viscosity is higher by 2 to 3 orders of magnitude while at low perturbations the enhancement is by 1–2 order of magnitude as compared to earlier results. Also the damping time is 2–3 orders of magnitude lower implying that the star reaches stability much earlier than in MIT bag model calculations.

  13. Bulk density and compaction behavior of knife mill chopped switchgrass, wheat straw, and corn stover.

    Science.gov (United States)

    Chevanan, Nehru; Womac, Alvin R; Bitra, Venkata S P; Igathinathane, C; Yang, Yuechuan T; Miu, Petre I; Sokhansanj, Shahab

    2010-01-01

    Bulk density of comminuted biomass significantly increased by vibration during handling and transportation, and by normal pressure during storage. Compaction characteristics affecting the bulk density of switchgrass, wheat straw, and corn stover chopped in a knife mill at different operating conditions and using four different classifying screens were studied. Mean loose-filled bulk densities were 67.5+/-18.4 kg/m(3) for switchgrass, 36.1+/-8.6 kg/m(3) for wheat straw, and 52.1+/-10.8 kg/m(3) for corn stover. Mean tapped bulk densities were 81.8+/-26.2 kg/m(3) for switchgrass, 42.8+/-11.7 kg/m(3) for wheat straw, and 58.9+/-13.4 kg/m(3) for corn stover. Percentage changes in compressibility due to variation in particle size obtained from a knife mill ranged from 64.3 to 173.6 for chopped switchgrass, 22.2-51.5 for chopped wheat straw and 42.1-117.7 for chopped corn stover within the tested consolidation pressure range of 5-120 kPa. Pressure and volume relationship of chopped biomass during compression with application of normal pressure can be characterized by the Walker model and Kawakita and Ludde model. Parameter of Walker model was correlated to the compressibility with Pearson correlation coefficient greater than 0.9. Relationship between volume reduction in chopped biomass with respect to number of tappings studied using Sone's model indicated that infinite compressibility was highest for chopped switchgrass followed by chopped wheat straw and corn stover. Degree of difficulty in packing measured using the parameters of Sone's model indicated that the chopped wheat straw particles compacted very rapidly by tapping compared to chopped switchgrass and corn stover. These results are very useful for solving obstacles in handling bulk biomass supply logistics issues for a biorefinery.

  14. Determination of elemental affinities by density fractionation of bulk coal samples

    Energy Technology Data Exchange (ETDEWEB)

    Querol, X.; Alastuey, A.; Juan, R.; Huerta, A.; Lopez- Soler, A.; Plana, F.; Chenery, S.R.N.; Robinson, J. [Consejo Superior de Investigaciones Cientificas, Barcelona (Spain). Institute of Earth Sciences ' Jaume Almera'

    2000-06-01

    In order to determine the trace elements affinities in the coal studied, density separations were carried out. Seven density fractions between {lt}1.3 and {gt}2.8 g/cc were obtained from the bulk coal samples by using heavy liquid mixtures of bromoform, tetrachlorethylene and xylene. For each density fraction the concentrations of the different mineral phases and major and trace elements were determined. After the correlation of the mineral and trace element contents, the affinity of each trace element was inferred. The mineral varieties and their contents in the bulk coal and density fractions were determined by X-ray diffraction analysis. If the method of density separation is used for the determination of the trace element affinities in coal, it is possible to determine the trace element associations by means of the simple correlation between major constituents (Al for the aluminium-silicate group, Fe for the sulphide group, and C for the organic matter) and the trace element contents for each density fraction. The results obtained by this method have lower resolution due to the fact that the high concentrations of some elements shown by the heaviest density fractions (rich in sulphides) obscure the correlation with other organic or mineral phases. 2 refs., 11 tabs.

  15. Bulk density of asteroid 243 Ida from the orbit of its satellite Dactyl

    Science.gov (United States)

    Belton, M.J.S.; Chapmant, C.R.; Thomas, P.C.; Davies, M.E.; Greenberg, R.; Klaasen, K.; Byrnes, D.; D'Amario, L.; Synnott, S.; Johnson, T.V.; McEwen, A.; Merline, W.J.; Davis, D.R.; Petit, J.-M.; Storrs, A.; Veverka, J.; Zellner, B.

    1995-01-01

    DURING its reconnaissance of the asteroid 243 Ida, the Galileo spacecraft returned images of a second object, 1993(243)1 Dactyl1 - the first confirmed satellite of an asteroid. Sufficient data were obtained on the motion of Dactyl to determine its orbit as a function of Ida's mass. Here we apply statistical and dynamical arguments to constrain the range of possible orbits, and hence the mass of Ida. Combined with the volume of Ida2, this yields a bulk density of 2.6??0.5 g cm-3. Allowing for the uncertainty in the porosity of Ida, this density range is consistent with a bulk chondritic composition, and argues against some (but not all) classes of meteoritic igneous rock types that have been suggested as compositionally representative of S-type asteroids like Ida.

  16. Balloon and core sampling for determining bulk density of alluvial desert soil

    Science.gov (United States)

    Andraski, B.J.

    1991-01-01

    Samples were collected from major strata in the upper 5 m of an alluvial soil profile in the Amargosa Desert of southern Nevada to compare rubber-balloon and drive-core bulk-density measurement methods. Outside the range of fine-soil texture, where soil consistency was either very loose or very hard, the core method appeared to sample inaccurately, resulting in bulk-density values less than those determined by the balloon method. Under the severe sampling conditions encountered, large decreases in the relative accuracy of the core method were not directly related to rock-fragment content, but were related to extremes in the cohesiveness of the strata sampled. -from Author

  17. Tractor tire aspect ratio effects on soil bulk density and cone index

    Science.gov (United States)

    A 580/70R38 tractor drive tire with an aspect ratio of 0.756 and a 650/75R32 tire with an aspect ratio of 0.804 were operated at two dynamic loads and two inflation pressures on a sandy loam and a clay loam with loose soil above a hardpan. Soil bulk density and cone index were measured just above t...

  18. Is the first hydration shell of lysozyme of higher density than bulk water?

    OpenAIRE

    Merzel, Franci; Smith, Jeremy C.

    2002-01-01

    Characterization of the physical properties of protein surface hydration water is critical for understanding protein structure and folding. Here, using molecular dynamics simulation, we provide an explanation of recent x-ray and neutron solution scattering data that indicate that the density of water on the surface of lysozyme is significantly higher than that of bulk water. The simulation-derived scattering profiles are in excellent agreement with the experiment. In the ...

  19. Determination of critical current density in melt-processed HTS bulks from levitation force measurements

    OpenAIRE

    Kordyuk, A. A.; Nemoshkalenko, V.V.; Viznichenko, R. V.; Habisreuther, T.; Gawalek, W.

    1999-01-01

    A simple approach to describe the levitation force measurements on melt-processed HTS bulks was developed. A couple of methods to determine the critical current density $J_c$ were introduced. The averaged $ab$-plane $J_c$ values for the field parallel to this plane were determined. The first and second levitation force hysteresis loops calculated with these $J_c$ values coincide remarkably well with the experimental data.

  20. Bulk density and water tensions in the soil on corn root production

    Directory of Open Access Journals (Sweden)

    João A. S. Nunes

    2016-04-01

    Full Text Available ABSTRACT Inadequate management of soil and water can cause changes in soil physical characteristics, resulting in lower root development. Thus the objective of the present study was to evaluate the dry matter production of corn roots under combinations of levels of bulk density and water tension in the soil. The experiment was conducted in a greenhouse in a randomized block design, based on a modified central composite design of a 52 fractional factorial scheme, of combinations of bulk densities (1.0, 1.2, 1.4, 1.6 and 1.8 Mg m-3 and water tensions in the soil (10, 20, 30 40 and 50 kPa, resulting in 13 treatments with four replicates. An Oxisol collected in the layer of 0-0.2 m was used. The pots were made of PVC (polyvinyl chloride tube with compacted soil in the middle layer. The tensiometers were installed at a depth of 0.15 m, remaining in the central region of the compacted layer. The experiment was collected 104 days after sowing. Root dry matter production of corn was limited by increased water stress and bulk density.

  1. Gamma-ray attenuation method as an efficient tool to investigate soil bulk density spatial variability

    Energy Technology Data Exchange (ETDEWEB)

    Pires, L.F., E-mail: lfpires@uepg.b [Laboratory of Soil Physics and Environmental Sciences, State University of Ponta Grossa, UEPG, C.E.P. 84.030-900 Ponta Grossa, PR (Brazil); Rosa, J.A. [Laboratory of Soil Physics, Agricultural Research Institute of Parana, IAPAR, C.E.P. 84.001-970 Ponta Grossa, PR (Brazil); Pereira, A.B. [Laboratory of Agrometeorology, State University of Ponta Grossa, UEPG, C.E.P. 84.030-900 Ponta Grossa, PR (Brazil); Arthur, R.C.J.; Bacchi, O.O.S. [Laboratory of Soil Physics, Center for Nuclear Energy in Agriculture, USP/CENA, C.E.P. 13.400-970 Piracicaba, SP (Brazil)

    2009-11-15

    The spatial variability of soil bulk density (rho{sub b}) was measured by using the volumetric ring method (VRM) and the gamma-ray attenuation method (GAM). Collimated radiation from 3.7 GBq of {sup 241}Am was used to evaluate the soil mass attenuation coefficient and its bulk density. Circular lead collimators were adjusted and aligned between source (D = 1, 2 and 3 mm) and detector (D = 4.5 mm). Results of GAM for average rho{sub b} provided good agreement with the corresponding values obtained gravimetrically. Variations in bulk density for different collimator dimensions can be attributed to multiple scattering after photons interaction with soil, mainly for 3 mm collimator size. The best result of rho{sub b} by the nuclear technique was obtained when rho{sub b} represents an average of the measurements for collimators of 1 and 2 mm. Another cause for the differences in rho{sub b} by GAM and VRM is the heterogeneity of soil when the collimated beam can interact with stones or large air-filled holes or channels present in the sample. Therefore, the pattern of spatial variability obtained by VRM was confirmed by GAM for all collimator sizes. This result is a good indication that GAM can be used with success to analyze soil spatial variability.

  2. Feasibility and limitations of bulk density assignment in MRI for head and neck IMRT treatment planning.

    Science.gov (United States)

    Chin, Alexander L; Lin, Alexander; Anamalayil, Shibu; Teo, Boon-Keng Kevin

    2014-01-01

    Head and neck cancers centered at the base of skull are better visualized on MRI than on CT. The purpose of this investigation was to investigate the accuracy of bulk density assignment in head and neck intensity-modulated radiation therapy (IMRT) treatment plan optimization. Our study investigates dose calculation differences between density-assigned MRI and CT, and identifies potential limitations related to dental implants and MRI geometrical distortion in the framework of MRI-only-based treatment planning. Bulk density assignment was performed and applied onto MRI to generate three MRI image sets with increasing levels of heterogeneity for seven patients: 1) MRIW: all water-equivalent; 2) MRIW+B: included bone with density of 1.53 g/cm3; and 3) MRIW+B+A: included bone and air. Using identical planning and optimization parameters, MRI-based IMRT plans were generated and compared to corresponding, forward-calculated, CT-based plans on the basis of target coverage, isodose distributions, and dose-volume histograms (DVHs). Phantom studies were performed to assess the magnitude and spatial dependence of MRI geometrical distortion. MRIW-based dose calculations overestimated target coverage by 16.1%. Segmentation of bone reduced differences to within 2% of the coverage area on the CT-based plan. Further segmentation of air improved conformity near air-tissue interfaces. Dental artifacts caused substantial target coverage overestimation even on MRIW+B+A. Geometrical distortion was less than 1 mm in an imaging volume 20 × 20 × 20 cm3 around scanner isocenter, but up to 4 mm at 17 cm lateral to isocenter. Bulk density assignment in the framework of MRI-only IMRT head and neck treatment planning is a feasible method with certain limitations. Bone and teeth account for the majority of density heterogeneity effects. While soft tissue is well visualized on MRI compared to CT, dental implants may not be visible on MRI and must be identified by other means and assigned

  3. Feasibility and limitations of bulk density assignment in MRI for head and neck IMRT treatment planning.

    Science.gov (United States)

    Chin, Alexander L; Lin, Alexander; Anamalayil, Shibu; Teo, Boon-Keng Kevin

    2014-01-01

    Head and neck cancers centered at the base of skull are better visualized on MRI than on CT. The purpose of this investigation was to investigate the accuracy of bulk density assignment in head and neck intensity-modulated radiation therapy (IMRT) treatment plan optimization. Our study investigates dose calculation differences between density-assigned MRI and CT, and identifies potential limitations related to dental implants and MRI geometrical distortion in the framework of MRI-only-based treatment planning. Bulk density assignment was performed and applied onto MRI to generate three MRI image sets with increasing levels of heterogeneity for seven patients: 1) MRIW: all water-equivalent; 2) MRIW+B: included bone with density of 1.53 g/cm3; and 3) MRIW+B+A: included bone and air. Using identical planning and optimization parameters, MRI-based IMRT plans were generated and compared to corresponding, forward-calculated, CT-based plans on the basis of target coverage, isodose distributions, and dose-volume histograms (DVHs). Phantom studies were performed to assess the magnitude and spatial dependence of MRI geometrical distortion. MRIW-based dose calculations overestimated target coverage by 16.1%. Segmentation of bone reduced differences to within 2% of the coverage area on the CT-based plan. Further segmentation of air improved conformity near air-tissue interfaces. Dental artifacts caused substantial target coverage overestimation even on MRIW+B+A. Geometrical distortion was less than 1 mm in an imaging volume 20 × 20 × 20 cm3 around scanner isocenter, but up to 4 mm at 17 cm lateral to isocenter. Bulk density assignment in the framework of MRI-only IMRT head and neck treatment planning is a feasible method with certain limitations. Bone and teeth account for the majority of density heterogeneity effects. While soft tissue is well visualized on MRI compared to CT, dental implants may not be visible on MRI and must be identified by other means and assigned

  4. Constraining the Bulk Density of 10m-Class Near-Earth Asteroid 2012 LA

    Science.gov (United States)

    Mommert, Michael; Hora, Joseph; Farnocchia, Davide; Trilling, David; Chesley, Steve; Harris, Alan; Mueller, Migo; Smith, Howard

    2016-08-01

    The physical properties of near-Earth asteroids (NEAs) provide important hints on their origin, as well as their past physical and orbital evolution. Recent observations seem to indicate that small asteroids are different than expected: instead of being monolithic bodies, some of them instead resemble loose conglomerates of smaller rocks, so called 'rubble piles'. This is surprising, since self-gravitation is practically absent in these bodies. Hence, bulk density measurements of small asteroids, from which their internal structure can be estimated, provide unique constraints on asteroid physical models, as well as models for asteroid evolution. We propose Spitzer Space Telescope observations of 10 m-sized NEA 2012 LA, which will allow us to constrain the diameter, albedo, bulk density, macroporosity, and mass of this object. We require 30 hrs of Spitzer time to detect our target with a minimum SNR of 3 in CH2. In order to interpret our observational results, we will use the same analysis technique that we used in our successful observations and analyses of tiny asteroids 2011 MD and 2009 BD. Our science goal, which is the derivation of the target's bulk density and its internal structure, can only be met with Spitzer. Our observations will produce only the third comprehensive physical characterization of an asteroid in the 10m size range (all of which have been carried out by our team, using Spitzer). Knowledge of the physical properties of small NEAs, some of which pose an impact threat to the Earth, is of importance for understanding their evolution and estimating the potential of destruction in case of an impact, as well as for potential manned missions to NEAs for either research or potential commercial uses.

  5. Direct determination of defect density of states in organic bulk heterojunction solar cells

    Science.gov (United States)

    Verma, Upkar K.; Tripathi, Durgesh C.; Mohapatra, Y. N.

    2016-09-01

    The measurement of the occupied trap density of states (DOS) is important for optimization of organic bulk heterojunction solar cells. We demonstrate a direct method for obtaining it from the trap related peak in capacitance-voltage characteristics under different levels of illumination, and its correlation with the dark current density-voltage characteristics. We use the method to measure the parameters of DOS, occupied trap distribution, and its temperature dependence for poly(3-hexathiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) based solar cells. The total occupied trap concentration is approximately 7 × 1015 cm-3 with a standard deviation for a truncated Gaussian distribution varying between 32 and 44 meV in the temperature range of 310-270 K within a total Gaussian DOS with a standard deviation of 92 meV.

  6. Large transport current density in bulk oriented-grained 123/Ag composites

    International Nuclear Information System (INIS)

    This paper reports on ceramic high temperature superconductors (HTS) that are inherently inferior in their mechanical properties. Addition of silver in bulk HTS has been shown to improve their mechanical properties. However, these HTS/Ag composites possess low transport critical current density typical of polycrystalline HTS. This paper deals with the development of a liquid-phase processing method that results in oriented-grained 123/Ag composites with large current carrying capability and enhanced mechanical properties. In this method, composites of 123 superconductor with up to 25 wt.% Ag addition are subjected to liquid-phase processing in air. Oriented-grained samples up to 10 mm long are obtained with Ag particles dispersed throughout the composites. Measurements on these oriented-grained samples using continuous direct current at 77K and zero applied magnetic field routinely give a transport critical current density in excess of 15,000 A/cm2. Magnetization measurements, however, show a Jc of 30,000 A/cm2 at 2 tesla. These results along with improved mechanical properties make these composites promising for bulk superconductivity applications. This work is supported by DARPA and the state of Texas

  7. Dense Shaped Refractory Products--Determination of Bulk Density, Apparent Porosity and True Porosity GB/T 2997-2000

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ 1 Scope This standard specifies the definition, principle, apparatus and materials, procedure, expression of results and test report of determination of bulk density, apparent porosity and true porosity of dense shaped refractory products.

  8. Dynamics of bulk electron heating and ionization in solid density plasmas driven by ultra-short relativistic laser pulses

    Science.gov (United States)

    Huang, L. G.; Kluge, T.; Cowan, T. E.

    2016-06-01

    The dynamics of bulk heating and ionization is investigated both in simulations and theory, which determines the crucial plasma parameters such as plasma temperature and density in ultra-short relativistic laser-solid target interactions. During laser-plasma interactions, the solid density plasma absorbs a fraction of laser energy and converts it into kinetic energy of electrons. A portion of the electrons with relativistic kinetic energy goes through the solid density plasma and transfers energy into the bulk electrons, which results in bulk electron heating. The bulk electron heating is finally translated into the processes of bulk collisional ionization inside the solid target. A simple model based on the Ohmic heating mechanism indicates that the local and temporal profile of bulk return current is essential to determine the temporal evolution of bulk electron temperature. A series of particle-in-cell simulations showing the local heating model is robust in the cases of target with a preplasma and without a preplasma. Predicting the bulk electron heating is then benefit for understanding the collisional ionization dynamics inside the solid targets. The connection of the heating and ionization inside the solid target is further studied using Thomas-Fermi model.

  9. Determination of mass density, dielectric, elastic, and piezoelectric constants of bulk GaN crystal.

    Science.gov (United States)

    Soluch, Waldemar; Brzozowski, Ernest; Lysakowska, Magdalena; Sadura, Jolanta

    2011-11-01

    Mass density, dielectric, elastic, and piezoelectric constants of bulk GaN crystal were determined. Mass density was obtained from the measured ratio of mass to volume of a cuboid. The dielectric constants were determined from the measured capacitances of an interdigital transducer (IDT) deposited on a Z-cut plate and from a parallel plate capacitor fabricated from this plate. The elastic and piezoelectric constants were determined by comparing the measured and calculated SAW velocities and electromechanical coupling coefficients on the Z- and X-cut plates. The following new constants were obtained: mass density p = 5986 kg/m(3); relative dielectric constants (at constant strain S) ε(S)(11)/ε(0) = 8.6 and ε(S)(11)/ε(0) = 10.5, where ε(0) is a dielectric constant of free space; elastic constants (at constant electric field E) C(E)(11) = 349.7, C(E)(12) = 128.1, C(E)(13) = 129.4, C(E)(33) = 430.3, and C(E)(44) = 96.5 GPa; and piezoelectric constants e(33) = 0.84, e(31) = -0.47, and e(15) = -0.41 C/m(2).

  10. High critical current densities in bulk MgB{sub 2} fabricated using amorphous boron

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, Miryala; Kenta, Nozaki; Murakami, Masato [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, Tokyo 135-8548 (Japan); Koblischka, Michael R. [Institute of Experimental Physics, Saarland University, P.O. Box 151150, 66041 Saarbruecken (Germany)

    2015-10-15

    We prepared bulk MgB{sub 2} from high-purity commercial powders of Mg metal (99.9% purity) and amorphous B (99% purity) powders using a single-step solid state reaction at 775 C for varying sintering duration from 1 to 10 h in pure argon atmosphere. X-ray diffraction analysis showed that all the samples were single phase MgB{sub 2}. The magnetization measurements confirmed a sharp superconducting transition with T{sub c,onset} at around 38.2-38.8 K. The critical current density (J{sub c}) values for the MgB{sub 2} samples produced at 1 h sintering time is the highest one in all processed materials here. Scanning electron microscopy analyses indicated that the sintering time has a crucial influence on the grain size. As a result, the highest J{sub c} value of 270 kA cm{sup -2} at 20 K and self-field was achieved in the sample produced at 775 C for 1 h. Our results clearly demonstrate that the optimization of the sintering conditions is essential to improve the bulk MgB{sub 2} performance. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Passive microwave sensing of soil moisture content - The effects of soil bulk density and surface roughness

    Science.gov (United States)

    Wang, J. R.

    1983-01-01

    Microwave radiometric measurements over bare fields of different surface roughness were made at frequencies of 1.4 GHz, 5 GHz, and 10.7 GHz to study the frequency dependence, as well as the possible time variation, of surface roughness. An increase in surface roughness was found to increase the brightness temperature of soils and reduce the slope of regression between brightness temperature and soil moisture content. The frequency dependence of the surface roughness effect was relatively weak when compared with that of the vegetation effect. Radiometric time-series observations over a given field indicate that field surface roughness might gradually diminish with time, especially after a rainfall or irrigation. The variation of surface roughness increases the uncertainty of remote soil moisture estimates by microwave radiometry. Three years of radiometric measurements over a test site revealed a possible inconsistency in the soil bulk density determination, which is an important factor in the interpretation of radiometric data.

  12. Relationships between soil moisture-holding properties and soil texture, organic matter content, and bulk density

    Science.gov (United States)

    Riley, H. C. F.

    1981-01-01

    Specimens from the surface horizon and the subsoil of 62 soil horizons in Hedmark and Oppland were investigated to study how the mechanical composition of the soil, the organic matter content and the bulk density affect their porosity and air capacity and their total and available water content. Most of the specimens belonged to the loam group, and a smaller number was from sandy and silty types of soil. Equations were established to make it possible to calculate the water retention curves and the amount of available water from the above mentioned parameters. As a rule, errors derived from the equations are no greater than those which are found in similar research in other countries.

  13. Dynamic monitoring of soil bulk density and infiltration rate during coal mining in sandy land with different vegetation

    Institute of Scientific and Technical Information of China (English)

    Yinli Bi; Hui Zou; Chenwei Zhu

    2014-01-01

    To investigate the effects of coal mining on soil physical properties, sandy lands with three major vegetation types (Salix psammophila, Populus simonii, and Artemisia ordosica) were investigated by the ring knife method and double-ring infiltrometer. Specifically, variations in soil bulk density and water infiltration rate and the influences of coal mining and vegetation type on the properties during different subsidence stages were studied at the Shendong Bulianta mine. The results showed that, in the period before mining, soil bulk density occurred in the order A. ordosica [ P. simonii [ S. psammophila, with a negative correlation between the initial infiltration rate and steady infiltration rate being observed. In the period during mining and 3 months after mining, there were no significant differences in soil bulk density and water infiltration rate among vegetation types. At 1 year after mining, the soil bulk density occurred in the order A. ordosica [ S. psammophila [ P. simonii, having a negative correlation with the steady infiltration rate. The water infil-tration depths of the S. psammophila, P. simonii and A. ordosica were 50, 60, and 30 cm, respectively. The infiltration characters were simulated by the Kostiakov equations, and the simulated and experimental results were consistent. Linear regression revealed that vegetation types and soil bulk density had significant effects on soil initial infiltration rate during the four study periods, and the infiltration rate of the period 1 year after mining was mainly influenced by the soil bulk density of the period before mining. The results indicated that vegetation types had significant effects on soil bulk density, and that the tree–shrub–grass mode was better than one single plantation for water conversation and vegetation recovery in sandy land subjected to mining.

  14. Occupation probabilities and current densities of bulk and edge states of a Floquet topological insulator

    Science.gov (United States)

    Dehghani, Hossein; Mitra, Aditi

    2016-05-01

    Results are presented for the occupation probabilities and current densities of bulk and edge states of half-filled graphene in a cylindrical geometry and irradiated by a circularly polarized laser. It is assumed that the system is closed and that the laser has been switched on as a quench. Laser parameters corresponding to some representative topological phases are studied: one where the Chern number of the Floquet bands equals the number of chiral edge modes, a second where anomalous edge states appear in the Floquet Brillouin zone boundaries, and a third where the Chern number is zero, yet topological edge states appear at the center and boundaries of the Floquet Brillouin zone. Qualitative differences are found for the high-frequency off-resonant and low-frequency on-resonant laser with edge states arising due to resonant processes occupied with a high effective temperature on the one hand, while edge states arising due to off-resonant processes occupied with a low effective temperature on the other. For an ideal half-filled system where only one of the bands in the Floquet Brillouin zone is occupied and the other empty, particle-hole and inversion symmetry of the Floquet Hamiltonian implies zero current density. However the laser switch-on protocol breaks the inversion symmetry, resulting in a net cylindrical sheet of current density at steady state. Due to the underlying chirality of the system, this current density profile is associated with a net charge imbalance between the top and bottom of the cylinders.

  15. [Spatial variation characteristics of surface soil water content, bulk density and saturated hydraulic conductivity on Karst slopes].

    Science.gov (United States)

    Zhang, Chuan; Chen, Hong-Song; Zhang, Wei; Nie, Yun-Peng; Ye, Ying-Ying; Wang, Ke-Lin

    2014-06-01

    Surface soil water-physical properties play a decisive role in the dynamics of deep soil water. Knowledge of their spatial variation is helpful in understanding the processes of rainfall infiltration and runoff generation, which will contribute to the reasonable utilization of soil water resources in mountainous areas. Based on a grid sampling scheme (10 m x 10 m) and geostatistical methods, this paper aimed to study the spatial variability of surface (0-10 cm) soil water content, soil bulk density and saturated hydraulic conductivity on a typical shrub slope (90 m x 120 m, projected length) in Karst area of northwest Guangxi, southwest China. The results showed that the surface soil water content, bulk density and saturated hydraulic conductivity had different spatial dependence and spatial structure. Sample variogram of the soil water content was fitted well by Gaussian models with the nugget effect, while soil bulk density and saturated hydraulic conductivity were fitted well by exponential models with the nugget effect. Variability of soil water content showed strong spatial dependence, while the soil bulk density and saturated hydraulic conductivity showed moderate spatial dependence. The spatial ranges of the soil water content and saturated hydraulic conductivity were small, while that of the soil bulk density was much bigger. In general, the soil water content increased with the increase of altitude while it was opposite for the soil bulk densi- ty. However, the soil saturated hydraulic conductivity had a random distribution of large amounts of small patches, showing high spatial heterogeneity. Soil water content negatively (P conductivity, while there was no significant correlation between the soil bulk density and saturated hydraulic conductivity.

  16. Soil resistivity over root area ratio, soil humidity, and bulk density: laboratory tests

    Science.gov (United States)

    Guastini, Enrico; Giambastiani, Yamuna; Preti, Federico

    2015-04-01

    Knowledge about root system distribution covers an important role in slope shallow stability stud-ies, as this factor grants an increase in soil geotechnical properties (soil cohesion and friction an-gle) and determines a different underground water circulation. Published studies (Amato et al., 2008 and 2011; Censini et al., 2014) about in situ application of ERT (Electrical Resistivity Tomo-graphy) analysis show how the root presence affects the measurable soil resistivity values, confirm-ing the suitability to investigate the application of such technique, aiming to estimate root density in soil with an indirect and non-invasive method. This study, laboratory-based and led on reconstructed samples in controlled condition, aim to find a correlation between the resistivity variations and the various factors that can affect them (humid-ity, bulk density, presence of foreign bodies, temperature). The tests involved a clay-loam soil (USDA classification) taken from Quaracchi (Florence, Italy), in an experimental fir-wood (Picea abies) owned by the Department of Agricultural, Food and For-estry System, Florence University, a previously chosen site for field ERT applications. The row ma-terial has been dried out in a lab stove, grounded and sieved at 2 mm, and then placed in a lexan box (30 x 20 x 20 cm) without compaction. Inside the sample have been inserted 3 series of 4 iron electrodes, insulated along the shaft and with the conductive end placed at three different depth: 2 cm from surface, in the middle of the sample and in contact with the bottom of the box; resistivity measures are conducted on the three levels using a Syscal R2 with electrodes connected in a dipole-dipole configuration. Root presence is simulated inserting bamboo spits (simple geometry, replicable "R.A.R.") in varying number from 0 to 16 in every area between two contiguous electrodes. The tests are repeated in time, monitoring the natural variations in humidity (evapotranspiration) and bulk

  17. Comparative Study on Super Fine Mesophase Powder and MCMB Used to Manufacture High-Density Isotropic Carbon Bulks

    Institute of Scientific and Technical Information of China (English)

    LI Tong-qi; HU Zi-jun; WANG Jun-shan; GUO Yu-ming; WANG Cheng-yang

    2006-01-01

    Mesocarbon microbeads (MCMB) and super fine mesophase powder (SFMP) were prepared firstly from a coal tar pitch and then hot-condensed into high-density isotropic carbon (HDIC) bulks under 160 Mpa and finally sintered at 1 000 ℃. By analyzing the thermogravimetric behavior of the MCMB and SFMP powders, their volume shrinkage and weight loss during sintering and the bulk density and flexural strengths of their sintered bulks, it was found that the smaller sizes and the richer β-resin contents of SFMP have facilitated formation of sintered bulks with more compact isotropic structure and higher flexural strengths than MCMB. Because of the filling and bonding effects of SFMP on MCMB bulks, addition of SFMP, albeit a little, can greatly increase the flexural strengths of sintered bulks of MCMB. However, adding MCMB, even a slight amount, into SFMP can severely impair the flexural strength of sintered bulks. This might be attributed to both the crack initiation along the boundaries between MCMB and SFMP and the formation of layered texture of MCMB sphere.

  18. Evaluation of the physical properties, bulk density and aggregate stability of potential substrates in quarry restoration.

    Science.gov (United States)

    Jordan, M.; Garcia-Orenes, F.; Mataix-Solera, J.; Garcia-Sanchez, E.

    2012-04-01

    Quarrying activity entails significant environmental impact affecting the soil, water, plants, landscape, etc. One of the most important impacts is the loss of the productive layer of the soil and its vegetation cover. However, mining activities are absolutely necessary for human development; keeping them sustainable implicates looking for viable solutions for the restoration of these areas to prevent degradation during and after the exploitation period. The aim of this study was to evaluate different substrates obtained from different mixes of sewage sludge and different mine spoils, to check how they are effective in quarry restoration, and to establish good practises in mining restoration. Also, the study tried to approach two refuses, one deriving from mining activity, as are the mine spoils that need to be reused for their valorisation, and the other, sewage sludge, obtained in the water depuration process to acquire a cheap substrate for soil rehabilitation. This preliminary work, which is included in a larger study, shows the results obtained from two physical properties studied, bulk density and aggregate stability, as key properties in the substrate structure for use in mining area restoration. Two doses of composted sewage sludge (30 and 90 Tm/Ha), both very rich in calcium carbonate, were applied to two different mine spoils under lab conditions. The first material, of poor quality, originated from the acquisition of arid particles in crushed limestone (Z). It is characterized by stable ''coarse elements'' predominance (up to 75% of its weight), and by the presence of elevated percentages of sand. The other waste material tested comes from limestone extraction (basically formed by the levels of interspersed non-limestone materials and the remains of stripped soils (D)). The results show that the high dose of sewage sludge applied to a mix of the two mine spoils significantly increased the percentage of stable aggregates by more than 50% than the control

  19. Effects of soil bulk density on gas transport parameters and pore-network properties across a sandy field site

    DEFF Research Database (Denmark)

    Masís-Meléndez, F.; De Jonge, L. W.; Chamindu, Deepagoda;

    2015-01-01

    ) were derived from the gas diffusivity curve, and the analogous parameters convective percolation threshold (eCPT) and convective pore-network connectivity index (B2) from the air permeability curve. All six parameters showed significant negative correlations with bulk density. To further account......The gas diffusion coefficient, air permeability, and their interrelations with air-filled porosity are essential for characterization of diffusive and convective transport of gases in soils. Variations in soil bulk density can affect water retention, air-filled pore space, and pore...

  20. Passive microwave sensing of soil moisture content: Soil bulk density and surface roughness

    Science.gov (United States)

    Wang, J. R.

    1982-01-01

    Microwave radiometric measurements over bare fields of different surface roughnesses were made at the frequencies of 1.4 GHz, 5 GHz, and 10.7 GHz to study the frequency dependence as well as the possible time variation of surface roughness. The presence of surface roughness was found to increase the brightness temperature of soils and reduce the slope of regression between brightness temperature and soil moisture content. The frequency dependence of the surface roughness effect was relatively weak when compared with that of the vegetation effect. Radiometric time series observation over a given field indicated that field surface roughness might gradually diminish with time, especially after a rainfall or irrigation. This time variation of surface roughness served to enhance the uncertainty in remote soil moisture estimate by microwave radiometry. Three years of radiometric measurements over a test site revealed a possible inconsistency in the soil bulk density determination, which turned out to be an important factor in the interpretation of radiometric data.

  1. Bulk density, water content and hydraulic properties of a sandy loam soil following conventional or strip tillage

    Science.gov (United States)

    We evaluated the effects of conventional (CT) and strip (ST) tillage practices on bulk density ('b), water content ('w), infiltration rate (Ir) and hydraulic conductivity (Ks) of plots in a Lihen sandy loam soil during the 2007 and 2008 growing seasons. We measured 'b and 'w using soil cores collect...

  2. Tillage Effects on Bulk Density and Hydraulic Properties of a Sandy Loam Soil in the Mon-Dak Region, USA

    Science.gov (United States)

    We evaluated the effects of conventional (CT) and strip (ST) tillage practices on bulk density (BD), water content (MC), infiltration rate (Ir) and hydraulic conductivity (Ks) in a Lihen sandy loam soil. Soil cores were collected from each plot at 0 to 10 and 10 to 30 cm depths under each tillage pr...

  3. Dynamic effects of soil bulk density on denitrification and mineralisation by 15N labelled lettuce residue and paper wastes

    International Nuclear Information System (INIS)

    Two laboratory incubation experiments aimed to study the denitrification and mineralisation influenced by different additives (15N labelled lettuce residue, paper wastes and mixture of both) and soil bulk densities were carried out by means of acetylene inhibition at the constant 15 degree C for 107 and 90 days, respectively. The results showed that the changes of N2O, CO2 emission rates, inorganic nitrogen (NO3- and NH4+), total N and 15N abundance in the soils which were affected by adding lettuce residue, paper wastes and mixture of both were investigated. Soil denitrification rate increased after lettuce residue was added into soil for 8 days. The maximum rate of N2O emission was 15 times higher than that in soil without any additive. However, paper wastes did not increase N2O emission in the first 8 days compared with other treatments, mixed residue and paper wastes could promote soil microbial activity, but N2O emission was lower than that in the soil with lettuce residue added and higher than that with paper wastes, indicating that mixture of residue and paper wastes was benefit to soil nitrogen immobilisation. CO2 emission in all the treatments were declined to the same level on the 107 th day. In the treatment added mixed residues and paper wastes, the released CO2 quantities were higher than those in other treatments every day. Effect of different bulk density on N2O and CO2 emission were response to the change of bulk density, it seems that N2O and CO2 emission increased with bulk density. High bulk density could affect decomposition of paper wastes and NO3-, NH4+ concentration. (30 ref., 10 tabs.)

  4. Effects of Nb and Si on densities of valence electrons in bulk and defects of Fe3Al alloys

    Institute of Scientific and Technical Information of China (English)

    邓文; 钟夏平; 黄宇阳; 熊良钺; 王淑荷; 郭建亭; 龙期威

    1999-01-01

    Positron lifetime measurements have been performed in binary Fe3Al and Fe3Al doping with Nb or Si alloys. The densities of valence electrons of the bulk and microdefects in all tested samples have been calculated by using the positron lifetime parameters. Density of valence electron is low in the bulk of Fe3Al alloy. It indicates that, the 3d electrons in a Fe atom have strong-localized properties and tend to form covalent bonds with Al atoms, and the bonding nature in Fe3Al is a mixture of metallic and covalent bonds. The density of valence electron is very low in the defects of Fe3Al grain boundary, which makes the bonding cohesion in grain boundary quite weak. The addition of Si to Fe3Al gives rise to the decrease of the densities of valence electrons in the bulk and the grain boundary thus the metallic bonding cohesion. This makes the alloy more brittle. The addition of Nb to Fe3Al results in the decrease of the ordering energy of the alloy and increases the density of valence electron and th

  5. Assessing the spatial and field dependence of the critical current density in YBCO bulk superconductors by scanning Hall probes

    Energy Technology Data Exchange (ETDEWEB)

    Hengstberger, F; Eisterer, M; Zehetmayer, M; Weber, H W [Atomic Institute of the Austrian Universities, Vienna University of Technology, Stadionallee 2, 1020 Vienna (Austria)], E-mail: hengstb@ati.ac.at

    2009-02-15

    Although the flux density map of a bulk superconductor provides in principle sufficient information for calculating the magnitude and the direction of the supercurrent flow, the inversion of the Biot-Savart law is ill conditioned for thick samples, thus rendering this method unsuitable for state of the art bulk superconductors. If a thin (<1 mm) slab is cut from the bulk, the inversion is reasonably well conditioned and the variation of the critical current density in the sample can be calculated with adequate spatial resolution. Therefore a novel procedure is employed, which exploits the symmetry of the problem and solves the equations non-iteratively, assuming a planar thickness-independent current density. The calculated current density at a certain position is found to depend on the magnetic induction. In this way the average field dependence of the critical current density J{sub c}(B) is also obtained at low fields, which is not accessible to magnetization measurements due to the self-field of the sample. It is further shown that an evaluation of magnetization loops, taking the self-field into account, results in a similar dependence in the field range accessible to this experiment.

  6. First principles study on the charge density and the bulk modulus of the transition metals and their carbides and nitrides

    Institute of Scientific and Technical Information of China (English)

    Li Cheng-Bin; Li Ming-Kai; Yin Dong; Liu Fu-Qing; Fan Xiang-Jun

    2005-01-01

    A first principles study of the electronic properties and bulk modulus (B0) of the fcc and bcc transition metals,transition metal carbides and nitrides is presented. The calculations were performed by plane-wave pseudopotential method in the framework of the density functional theory with local density approximation. The density of states and the valence charge densities of these solids are plotted. The results show that B0 does not vary monotonically when the number of the valence d electrons increases. B0 reaches a maximum and then decreases for each of the four sorts of solids. It is related to the occupation of the bonding and anti-bonding states in the solid. The value of the valence charge density at the midpoint between the two nearest metal atoms tends to be proportional to B0.

  7. Laboratory scale investigation to improve the productivity of stamp charge coke oven through optimisation of bulk density of coal cake

    Energy Technology Data Exchange (ETDEWEB)

    Dash, P.S.; Krishnan, S.H.; Sharma, R.; Banerjee, P.K.; Haldar, S.K. [Tata Steel, Jamshedpur (India)

    2005-07-01

    In the recent past, it was realised that the gross coke yield was going down as a result of lower oven throughput in the stamp charged batteries of Tata Steel. The basic reason for this being the net reduction in the ash content of the coal blend used due to the incorporation of higher percentage of low ash imported coals and reduction in the ash content of captive coals through washing. The coals having higher ash content improves the bulk density, as the specific gravity of ash is higher than that of pure coal. Moreover, the ash components have affinity for water and pure coal repels water, which in case of pure coal, works against the holding together of the blend. Hence, lower the ash content, less is the bulk density of cake under identical stamping energy and lower the bulk density, less is the oven throughput. In order to maximise the oven throughput and productivity, a study was conducted in the laboratory mainly to assess the effect of various blend constituents and their ash content on the bulk density of coal charge. The effect of ash content on the coal cake stability has also been dealt with. This study, in short, is a useful tool for selecting the right type of coals and designing the optimum blend for stamp charging to achieve maximum throughput and productivity. In addition, studies were also carried out to assess the effect of addition of various binders on coal cake stability at lower moisture level which would also help in achieving higher throughput and productivity.

  8. A general extrudate bulk density model for both twin-screw and single-screw extruder extrusion cooking processes

    OpenAIRE

    Cheng, Hongyuan; Friis, Alan; Høeg Hansen, Jonas; Tolderlund Rasmussen, Hanne

    2010-01-01

    Effects of extrusion parameters and raw materials on extrudate expansion are respectively investigated in a twin-screw extruder and a single-screw extruder extrusion cooking experiments for fish feed, wheat, and oat & wheat mixture processing. A new phenomenological model is proposed to correlated extrudate bulk density, extrusion parameters and raw material changes based on the experimental results. The average absolute deviation (AAD) of the correlation is 2.2% for fish feed extrusion in th...

  9. Impact of Molecular Orientation and Packing Density on Electronic Polarization in the Bulk and at Surfaces of Organic Semiconductors.

    Science.gov (United States)

    Ryno, Sean M; Risko, Chad; Brédas, Jean-Luc

    2016-06-01

    The polarizable environment surrounding charge carriers in organic semiconductors impacts the efficiency of the charge transport process. Here, we consider two representative organic semiconductors, tetracene and rubrene, and evaluate their polarization energies in the bulk and at the organic-vacuum interface using a polarizable force field that accounts for induced-dipole and quadrupole interactions. Though both oligoacenes pack in a herringbone motif, the tetraphenyl substituents on the tetracene backbone of rubrene alter greatly the nature of the packing. The resulting change in relative orientations of neighboring molecules is found to reduce the bulk polarization energy of holes in rubrene by some 0.3 eV when compared to tetracene. The consideration of model organic-vacuum interfaces highlights the significant variation in the electrostatic environment for a charge carrier at a surface although the net change in polarization energy is small; interestingly, the environment of a charge even just one layer removed from the surface can be viewed already as representative of the bulk. Overall, it is found that in these herringbone-type layered crystals the polarization energy has a much stronger dependence on the intralayer packing density than interlayer packing density. PMID:27183361

  10. Impact of Molecular Orientation and Packing Density on Electronic Polarization in the Bulk and at Surfaces of Organic Semiconductors

    KAUST Repository

    Ryno, Sean M.

    2016-05-16

    The polarizable environment surrounding charge carriers in organic semiconductors impacts the efficiency of the charge transport process. Here, we consider two representative organic semiconductors, tetracene and rubrene, and evaluate their polarization energies in the bulk and at the organic-vacuum interface using a polarizable force field that accounts for induced-dipole and quadrupole interactions. Though both oligoacenes pack in a herringbone motif, the tetraphenyl substituents on the tetracene backbone of rubrene alter greatly the nature of the packing. The resulting change in relative orientations of neighboring molecules is found to reduce the bulk polarization energy of holes in rubrene by some 0.3 eV when compared to tetracene. The consideration of model organic-vacuum interfaces highlights the significant variation in the electrostatic environment for a charge carrier at a surface although the net change in polarization energy is small; interestingly, the environment of a charge even just one layer removed from the surface can be viewed already as representative of the bulk. Overall, it is found that in these herringbone-type layered crystals the polarization energy has a much stronger dependence on the intralayer packing density than interlayer packing density.

  11. Impact of Molecular Orientation and Packing Density on Electronic Polarization in the Bulk and at Surfaces of Organic Semiconductors.

    Science.gov (United States)

    Ryno, Sean M; Risko, Chad; Brédas, Jean-Luc

    2016-06-01

    The polarizable environment surrounding charge carriers in organic semiconductors impacts the efficiency of the charge transport process. Here, we consider two representative organic semiconductors, tetracene and rubrene, and evaluate their polarization energies in the bulk and at the organic-vacuum interface using a polarizable force field that accounts for induced-dipole and quadrupole interactions. Though both oligoacenes pack in a herringbone motif, the tetraphenyl substituents on the tetracene backbone of rubrene alter greatly the nature of the packing. The resulting change in relative orientations of neighboring molecules is found to reduce the bulk polarization energy of holes in rubrene by some 0.3 eV when compared to tetracene. The consideration of model organic-vacuum interfaces highlights the significant variation in the electrostatic environment for a charge carrier at a surface although the net change in polarization energy is small; interestingly, the environment of a charge even just one layer removed from the surface can be viewed already as representative of the bulk. Overall, it is found that in these herringbone-type layered crystals the polarization energy has a much stronger dependence on the intralayer packing density than interlayer packing density.

  12. The influence of post-growth thermal treatments on the critical current density of TSMG YBCO bulk superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Diko, P; Antal, V; Zmorayova, K; Sefcikova, M; Kovac, J [Institute of Experimental Physics SAS, Watsonova 47, 04001 Kosice (Slovakia); Chaud, X [CNRS/CRETA, 25, Avenue des Martyrs, 38042 Grenoble Cedex 9 (France); Yao, X [Department of Physics, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Chen, I [Department of Materials Science and Engineering, National Cheng Kung University (NCKU) Tainan, Taiwan (China); Eisterer, M; Weber, H W [Vienna University of Technology, Atominstitut, Stadionallee 2, 1020 Vienna (Austria)

    2010-12-15

    Oxygenation and thermochemical post-growth treatments of top seeded melt-growth (TSMG) YBCO bulk superconductors can significantly influence critical current density. It is shown that, depending on oxygenation conditions and the size of 211 particles, different reductions of intrinsic critical current density values can be obtained due to the reduction in the sample cross-section caused by the presence of a/b-microcracks induced by 211 particles, and a/b- and a/c-cracks induced by oxygenation. The possibility of eliminating oxygenation cracks by high pressure oxygenation and consequently significantly increasing the macroscopic critical current density is demonstrated. An effective dopant concentration for chemical pinning is proposed and possible clustering of substitutions in the Y123 lattice by thermochemical treatments is shown.

  13. Study of Bulk modulus, Volume, Energy, lattice parameters and magnetic moments in rare earth hexaborides using density functional theory

    International Nuclear Information System (INIS)

    We have calculated the theoretical lattice parameters, Bulk modulus, volume, energy, lattice parameters and magnetic moments for RB6 (R=La, Ce, Pr and Sm) of CaB6 type crystal structure with space group Pm3m using full potential linearized augmented plane wave (FP-LAPW) method. The bulk modulus was found to be 9.56 % higher for LaB6 and 2.4% lower for CeB6 compared to the experimental results Gupta et al. [4] and Ogita et al [5], Magnetic moments for LaB6, CeB6 were found in qualitative agreement with the earlier reported results. The results based on generalized gradient approximation (GGA) were found and compared with local spin density approximation (LSDA) results for CeB6 and SmB6 as well.

  14. Universal bulk charge-density-wave (CDW) correlations in the cuprate superconductors

    Science.gov (United States)

    Tabis, Wojciech

    2014-03-01

    The recent observation of bulk CDW order in YBa2Cu3O8+δ(YBCO) in competition with superconductivity is a significant development. Using Cu L-edge resonant X-ray scattering, we also observe bulk CDW order in HgBa2CuO4+δ(Hg1201 Tc = 72K). The correlations appear below TCDW ~ 200K, well below the pseudogap temperature T* ~ 320K associated with unusual magnetism, but coincident with the onset of Fermi-liquid-like charge transport. In contrast to YBCO, we observe no decrease of the CDW amplitude below Tc, and the correlation length is short and temperature independent. CDW correlations therefore are a universal property of underdoped cuprates, enhanced by low structural symmetry and a magnetic field, but fundamentally not in significant competition with superconductivity. We also discuss the relationship between the CDW modulation wave vector and the Fermi surface area extracted from QO experiments. Work supported by DOE-BES. In collaboration with Y. Li, M. Le Tacon, L. Braicovich, A. Kreyssig, M. Minola, G. Dellea, E. Weschke, M. Veit, A. Goldman, T. Schmitt, G. Ghiringhelli, N. Barisic, M.K. Chan, C. Dorow, G. Yu, X. Zhao, B. Keimer, M. Greven.

  15. Assessment of some soil thermal conductivity models via variations in temperature and bulk density at low moisture range

    Science.gov (United States)

    Mahdavi, Seyed Mohamad; Neyshabouri, Mohammad Reza; Fujimaki, Haruyuki

    2016-08-01

    Simulation of heat transfer in soil under steady and unsteady situations requires reliable estimate of soil thermal conductivity (λ) at varying environmental conditions. In the current work several soil thermal conductivity predicting models including I) de Vries, II) Campbell, III) combined de Vries and Campbell and IV) de Vries-Nobre were evaluated for the four soils of coarse sand, sandy loam, loam and clay loam textured at varying in temperature and bulk density at low moisture range. Thermal conductivities measured by the cylindrical probe method served as the reference for models assessment. Results showed that approximately same thermal conductivities obtained by the five methods at low moisture range (θ ≤ 0.05 m3/m3). Also the de Vries and de Vries-Campbell models produced accurate than Campbell and de vries-Nobre models. The accuracy of the two models increased with soil compaction but decreased with temperature rise. Campbell model showed more reliability at higher (311.16 and 321.16 K) temperatures; but its accuracy declined with soil compaction in current work. It seems that assuming needle shape for the soil particles is far away from the reality whereas assuming spherical shapes may be more realistic and produced more satisfactory prediction of thermal conductivity. The compaction would alter particle arrangement and may increase the contact area of particles; and then make them behave more or less spherical shape.it seems thermal conductivity in solid particles increase via increasing in temperature. Since a modified mineral shape factor, g m , was developed as a combination between sphere and needle according to geometric mean particle diameter as well as bulk density and temperature as modifying factors. This factor increased the accuracy of de Vries-Nobre model up to 10.37%. Regarding nonlinear regression model, moisture content, bulk density, temperature and quartz content demonstrated significant effect on soil thermal conductivity in our

  16. Dosimetric evaluation of synthetic CT relative to bulk density assignment-based magnetic resonance-only approaches for prostate radiotherapy

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) has been incorporated as an adjunct to CT to take advantage of its excellent soft tissue contrast for contouring. MR-only treatment planning approaches have been developed to avoid errors introduced during the MR-CT registration process. The purpose of this study is to evaluate calculated dose distributions after incorporating a novel synthetic CT (synCT) derived from magnetic resonance simulation images into prostate cancer treatment planning and to compare dose distributions calculated using three previously published MR-only treatment planning methodologies. An IRB-approved retrospective study evaluated 15 prostate cancer patients that underwent IMRT (n = 11) or arc therapy (n = 4) to a total dose of 70.2-79.2 Gy. Original treatment plans were derived from CT simulation images (CT-SIM). T1-weighted, T2-weighted, and balanced turbo field echo images were acquired on a 1.0 T high field open MR simulator with patients immobilized in treatment position. Four MR-derived images were studied: bulk density assignment (10 HU) to water (MRW), bulk density assignments to water and bone with pelvic bone values derived either from literature (491 HU, MRW+B491) or from CT-SIM population average bone values (300 HU, MRW+B300), and synCTs. Plans were recalculated using fixed monitor units, plan dosimetry was evaluated, and local dose differences were characterized using gamma analysis (1 %/1 mm dose difference/distance to agreement). While synCT provided closest agreement to CT-SIM for D95, D99, and mean dose (<0.7 Gy (1 %)) compared to MRW, MRW+B491, and MRW+B300, pairwise comparisons showed differences were not significant (p < 0.05). Significant improvements were observed for synCT in the bladder, but not for rectum or penile bulb. SynCT gamma analysis pass rates (97.2 %) evaluated at 1 %/1 mm exceeded those from MRW (94.7 %), MRW+B300 (94.0 %), or MRW+B491 (90.4 %). One subject’s synCT gamma (1 %/1 mm) results (89.9 %) were lower than MRW

  17. Determination of element affinities by density fractionation of bulk coal samples

    Energy Technology Data Exchange (ETDEWEB)

    Querol, X.; Klika, Z.; Weiss, Z.; Finkelman, R.B.; Alastuey, A.; Juan, R.; Lopez-Soler, A.; Plana, F.; Kolker, A.; Chenery, S.R.N. [CSIC, Barcelona (Spain). Institute of Earth Sciences ' Jaume Almera'

    2001-01-01

    A review has been made of the various methods of determining major and trace element affinities for different phases, both mineral and organic in coals, citing their various strengths and weaknesses. These include mathematical deconvolution of chemical analyses, direct microanalysis, sequential extraction procedures and density fractionation. A new methodology combining density fractionation with mathematical deconvolution of chemical analyses of whole coals and their density fractions has been evaluated. These coals formed part of the IEA Coal Research project on the Modes of Occurrence of Trace Elements in Coal. Results were compared to a previously reported sequential extraction methodology and showed good agreement for most elements. For particular elements (Be, Mo, Cu, Se and REEs) in specific coals where disagreement was found, it was concluded that the occurrence of rare trace element bearing phases may account for the discrepancy, and modifications to the general procedure must be made to account for these. 27 refs., 1 fig., 10 tabs.

  18. Bulk Densities of Binary Asteroids from the Warm Spitzer NEO Survey

    NARCIS (Netherlands)

    Kistler, John; Trilling, D. E.; Mueller, M.; Hora, J. L.; Harris, A. W.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Emery, J. P.; Fazo, G.; Mainzer, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.; Thomas, C. A.

    2010-01-01

    The Warm Spitzer NEO survey, ExploreNEOs, will observe approximately 700 Near Earth Asteroids. Several of these objects are known to be binary asteroid systems. Binary systems are interesting due to the unique opportunity they present for determining the masses and densities of their constituent bod

  19. Effects of density difference of constituent elements on glass formation in TiCu-based bulk metallic glasses

    Institute of Scientific and Technical Information of China (English)

    Zhongyan Zhang; Zengbao Jiao; Jie Zhou; Yuan Wu; Hui Wang; Xiongjun Liu; Zhaoping Lun

    2013-01-01

    Glass formation is generally favored by a large atomic size mismatch among constituent elements, which usually leads to large density differences among them as well. During melting, elemental segregation occurs due to Stokes’ law and then inevitably affects glass formation. In this paper, such effects on glass-forming ability in a TiCu-based alloy system have been demonstrated. In the bulk glass-forming composition Ti43Cu42Hf14Si1, macroscopic segregation of Si was observed in the as-melted ingots and silicon was completely depleted in the as-cast rods. In another Ti33Cu47Ni8Zr11Si1 alloy, nevertheless, the effects of density differences among the constituent elements were less severe. It was also confirmed that using proper pre-alloys could be an effective way in alleviating the side effects of the elemental segregation.

  20. Diffusion of Chloride Ions in Soils: Ⅰ.Influences of Soil Moisture,Bulk Density and Temperature

    Institute of Scientific and Technical Information of China (English)

    XUMINGGANG; ZHANGYIPING; 等

    1997-01-01

    Diffusion coefficients of chlorde ions in four soils of different exture with varying effective moisture content and varying bulk density from 1.1 to 1.6 g cm3 under three different temperatures were determined by the diffusion-cell method using 36Cl-labelled CaCl2 solution.The result showed that activation energy decreased with water content,which indicated that the threshold fro diffusion was lower at a higher soil moisture rate .Therefor,the diffusion coefficient(D) of chloride ions in soil increased consistently with soil moisture,Although a near linear increase in the diffusion coefficient with increasing soil moisture or bulk density in all the soils was observed,the increase rate in different soils was not the same.The D value increased with teperature,and with temperature increased by 10℃ in the range from 5℃to 45℃ the D valve increased by 10%-30%,averaging about 20%.

  1. Prediction of soil organic carbon concentration and soil bulk density of mineral soils for soil organic carbon stock estimation

    Science.gov (United States)

    Putku, Elsa; Astover, Alar; Ritz, Christian

    2016-04-01

    Soil monitoring networks provide a powerful base for estimating and predicting nation's soil status in many aspects. The datasets of soil monitoring are often hierarchically structured demanding sophisticated data analyzing methods. The National Soil Monitoring of Estonia was based on a hierarchical data sampling scheme as each of the monitoring site was divided into four transects with 10 sampling points on each transect. We hypothesized that the hierarchical structure in Estonian Soil Monitoring network data requires a multi-level mixed model approach to achieve good prediction accuracy of soil properties. We used this database to predict soil bulk density and soil organic carbon concentration of mineral soils in arable land using different statistical methods: median approach, linear regression and mixed model; additionally, random forests for SOC concentration. We compared the prediction results and selected the model with the best prediction accuracy to estimate soil organic carbon stock. The mixed model approach achieved the best prediction accuracy in both soil organic carbon (RMSE 0.22%) and bulk density (RMSE 0.09 g cm-3) prediction. Other considered methods under- or overestimated higher and lower values of soil parameters. Thus, using these predictions we calculated the soil organic carbon stock of mineral arable soils and applied the model to a specific case of Tartu County in Estonia. Average estimated SOC stock of Tartu County is 54.8 t C ha-1 and total topsoil SOC stock 1.8 Tg in humus horizon.

  2. Estimating the density scaling exponent of viscous liquids from specific heat and bulk modulus data

    OpenAIRE

    Pedersen, Ulf R.; Hecksher, Tina; Jakobsen, Bo; Schrøder, Thomas B.; Gnan, Nicoletta; Bailey, Nicholas P.; Dyre, Jeppe C.

    2009-01-01

    It was recently shown by computer simulations that a large class of liquids exhibits strong correlations in their thermal fluctuations of virial and potential energy [Pedersen et al., Phys. Rev. Lett. 100, 015701 (2008)]. Among organic liquids the class of strongly correlating liquids includes van der Waals liquids, but excludes ionic and hydrogen-bonding liquids. The present note focuses on the density scaling of strongly correlating liquids, i.e., the fact their relaxation time tau at diffe...

  3. On valence electron density, energy dissipation and plasticity of bulk metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Pang, J.J.; Tan, M.J. [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 639798 Singapore (Singapore); Liew, K.M., E-mail: kmliew@cityu.edu.hk [Department of Civil and Architectural Engineering, City University of Hong Kong, Kowloon (Hong Kong)

    2013-11-15

    Highlights: ► Relationship between valence electron density and plasticity of metallic glasses. ► Poisson's ratio increases as electron density decreases. ► Energy dissipation proposed to understand plasticity. ► Low electron density indicates small activation energy. -- Abstract: In conventional crystalline alloys, valence electron density (VED) is one of the most significant factors in determining their phase stability and mechanical properties. Extending the concept to metallic glasses (MGs), it is found, not totally surprisingly, that their mechanical properties are VED-dependent as in crystalline alloys. Interestingly, the whole VED region can be separated into two zones: Zone 1 consists of Mg-, Ca-, and RE-based (RE for rare earth) alloys; Zone 2 consists of the rest of MGs. In either zone, for each type of MGs, Poisson's ratio generally decreases as VED increases. From the energy dissipation viewpoint proposed recently, the amorphous plasticity is closely related to the activation energy for the operation of shear-transformation-zones (STZs). Smaller STZ activation energy suggests higher ductility because STZs with lower activation energy are able to convert deformation work more efficiently into configurational energy rather than heat, which yields mechanical softening and advances the growth of shear bands (SBs). Following this model, it is revealed that the activation energies for STZ operation and crystallization are certainly proportional to VED. Thus, it is understood that, in Zone 2, MGs have a smaller VED and hence lower activation energies which are favorable for ductility and Poisson's ratio. In Zone 1, MGs have the lowest VED but apparent brittleness because either of low glass transition temperature and poor resistance to oxidation or of a large fraction of covalent bonds.

  4. Evaluating effect of surface state density at the interfaces in degraded bulk heterojunction organic solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Swati, E-mail: drswatia@yahoo.com [Department of Physics, Zakir Husain College, University of Delhi, Delhi 110002 (India); Singh, Vinamrita [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Arora, Manoj [Department of Physics, Ramjas College, University of Delhi, Delhi 110007 (India); Pal Tandon, Ram [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2012-08-01

    Degradation and short shelf life have been observed experimentally in poly(3-hexylthiophene) (P3HT): 6,6-phenyl C61-butyric acid methyl ester (PCBM) based blend solar cells. Both dark and illuminated current-voltage characteristics could be explained quantitatively with a proposed single model for a typical degraded organic solar cell-glass/ITO/PEDOT:PSS/P3HT:PCBM/Al. It has been found that surface state density, interface thickness, tunneling coefficient and occupation probabilities of the interface states becomes important with the passage of time. To look into the problem the activity at ITO/PEDOT:PSS and P3HT:PCBM/Al interfaces are studied using realistic values of the interfaces. The experimental J-V characteristics is well explained with the inclusion of tunneling current through these surface states and becomes the dominant current component for the degraded cell. It is also found that surface state density increases to 10{sup 12}-10{sup 13} cm{sup -2} eV{sup -1}, which has been verified with C-V measurements and also is in agreement with our proposed model for BHJ solar cell after 150 h of fabrication.

  5. The effect of fracture density and stress state on the static and dynamic bulk moduli of Westerly granite

    Science.gov (United States)

    Blake, O. O.; Faulkner, D. R.

    2016-04-01

    Elastic properties are key parameters during the deformation of rocks. They can be measured statically or dynamically, but the two measurements are often different. In this study, the static and dynamic bulk moduli (Kstatic and Kdynamic) were measured at varying effective stress for dry and fluid-saturated Westerly granite with controlled fracture densities under isotropic and differential stress states. Isotropic fracturing of different densities was induced in samples by thermal treatment to 250, 450, 650, and 850°C. Results show that fluid saturation does not greatly affect static moduli but increases dynamic moduli. Under isotropic loading, high fracture density and/or low effective pressure results in a low Kstatic/Kdynamic ratio. For dry conditions Kstatic/Kdynamic approaches 1 at low fracture densities when the effective pressure is high, consistent with previous studies. Stress-induced anisotropy exists under differential stress state that greatly affects Kstatic compared to Kdynamic. As a result, the Kstatic/Kdynamic ratio is higher than that for the isotropic stress state and approaches 1 with increasing axial loading. The effect of stress-induced anisotropy increases with increasing fracture density. A key omission in previous studies comparing static and dynamic properties is that anisotropy has not been considered. The standard methods for measuring static elastic properties, such as Poisson's ratio, Young's and shear modulus, involve subjecting the sample to a differential stress state that promotes anisotropy. Our results show that stress-induced anisotropy resulting from differential stress state is a major contributor to the difference between static and dynamic elasticity and is dominant with high fracture density.

  6. Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil.

    Science.gov (United States)

    Wickramarachchi, Praneeth; Kawamoto, Ken; Hamamoto, Shoichiro; Nagamori, Masanao; Moldrup, Per; Komatsu, Toshiko

    2011-12-01

    Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, ρ(b), and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D(p)/D(o), ratio of gas diffusion coefficients in soil and free air) and air permeability (k(a)) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting ρ(b) values ranging from 1.40 to 2.10 g cm(-3). Results showed that D(p) and k(a) values for the '+gravel' fraction (soil-air content (ε), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D(p) and k(a) was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D(p)/D(f), the ratio of measured D(p) to D(p) in total porosity (f), (ii) for air permeability k(a)/k(a)(,pF4.1), the ratio of measured k(a) to k(a) at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content (ε) to total porosity (f) (air saturation). Based on the normalized parameters, predictive power-law models for D(p)(ε/f) and k(a)(ε/f) models were developed based on a single parameter (water blockage factor M for D(p) and P for k(a)). The water blockage factors, M and P, were found to be linearly correlated to ρ(b) values, and the effects of dry bulk density on D(p) and k(a) for both '+gravel' and '-gravel' fractions were well accounted for by the new models. PMID:21813272

  7. The AM05 density functional applied to the water molecule, dimer, and bulk liquid

    Science.gov (United States)

    Mattsson, Ann E.; Mattsson, Thomas R.

    2009-03-01

    We show that the AM05 exchange-correlation density functional (Armiento and Mattsson, Phys. Rev. B 72, 085108 (2005)) yields a H2O dimer binding energy of 4.9 kcal/mol. The result is thus within 0.15 kcal/mol of CCSD(T) level theory (5.02 ±0.05 kcal/mol). We compare the AM05 results with those of five other functionals: LDA, PBE, PBEsol, RPBE, and BLYP. For liquid water, AM05 yields an O-O pair correlation function that is more structured than the ones of PBE and BLYP, which, in turn, are more structured than the one of RPBE. However, LDA and PBEsol yields more structured water than AM05. We confirm that accuracy in the water dimer binding energy is not a strong indicator for the fidelity of the resulting structure of liquid water. We will also report on the performance of AM05 for other systems and discuss the sub-system functional scheme used in the construction of AM05. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  8. Quantum information aspects on bulk and nano interacting Fermi system: A spin-space density matrix approach

    Science.gov (United States)

    Afzali, R.; Ebrahimian, N.; Eghbalifar, B.

    2016-10-01

    By approximating the energy gap, entering nano-size effect via gap fluctuation and calculating the Green's functions and the space-spin density matrix, the dependence of quantum correlation (entanglement, discord and tripartite entanglement) on the relative distance of two electron spins forming Cooper pairs, the energy gap and the length of bulk and nano interacting Fermi system (a nodal d-wave superconductor) is determined. In contrast to a s-wave superconductor, quantum correlation of the system is sensitive to the change of the gap magnitude and strongly depends on the length of the grain. Also, quantum discord oscillates. Furthermore, the entanglement length and the correlation length are investigated. Discord becomes zero at a characteristic length of the d-wave superconductor.

  9. Influence of optical interference and carrier lifetime on the short circuit current density of organic bulk heterojunction solar cells

    Institute of Scientific and Technical Information of China (English)

    You Hai-Long; Zhang Chun-Fu

    2009-01-01

    Based on simple analytical equations, short circuit current density (Jsc) of the organic bulk heterojunction solar cells has been calculated. It is found that the optical interference effect plays a very important role in the determination of JSC;and obvious oscillatory behaviour of Jsc was observed as a function of thickness. At the same time, the influence of JSC only increases the carrier lifetime on JSC also cannot be neglected. When the carrier lifetime is relatively short, at the initial stage and then decreases rapidly with the increase of active layer thickness. However, for a relatively long carrier lifetime, the exciton dissociation probability must be considered, and Jsc behaves wave-like with the increase of active layer thickness. The validity of this model is confirmed by the experimental results.

  10. The Relations Between Soil Water Retention Characteristics, Particle Size Distributions, Bulk Densities and Calcium Carbonate Contents for Danish Soils

    DEFF Research Database (Denmark)

    Jensen, Niels H.; Balstrøm, Thomas; Breuning-Madsen, Henrik

    2005-01-01

    A database containing about 800 soil profiles located in a 7-km grid covering Denmark has been used to develop a set of regression equations of soil water content at pressure heads –1, -10, -100 and –1500 kPa versus particle size distribution, organic matter, CaCO3 and bulk density. One purpose...... horizons or textural classes improved the regression equations. Compared to existing Danish equations based on much fewer observations the accuracies of the new equations were better. The equations also predicted the soil water content at the measured pressure heads more accurate than the pedotransfer...... on the equations a set of van Genuchten parameters for soil types in the Danish Soil Classification was elaborated. The prediction of soil water content, especially at pressure head –1 kPa, is more accurate using these van Genuchten parameters than using the pedotransfer functions developed in relation...

  11. A hybrid-exchange density functional study of the bonding and electronic structure in bulk CuFeS2

    Science.gov (United States)

    Martínez-Casado, Ruth; Chen, Vincent H.-Y.; Mallia, Giuseppe; Harrison, Nicholas M.

    2016-05-01

    The geometric, electronic, and magnetic properties of bulk chalcopyrite CuFeS2 have been investigated using hybrid-exchange density functional theory calculations. The results are compared with available theoretical and experimental data. The theoretical description of the bonding and electronic structure in CuFeS2 is analyzed in detail and compared to those computed for chalcocite (CuS2) and greigite (Fe3S4). In particular, the behavior of the 3d electrons of Fe3+ is discussed in terms of the Hubbard-Anderson model in the strongly correlated regime and found to be similarly described in both materials by an on-site Coulomb repulsion (U) of ˜8.9 eV and a transfer integral (t) of ˜0.3 eV.

  12. Influence of Critical Current Density on Guidance Force Decay of HTS Bulk Exposed to AC Magnetic Field Perturbation in a Maglev Vehicle System

    Science.gov (United States)

    Longcai, Zhang; Jianguo, Kong

    2012-07-01

    Superconducting maglev vehicle is one of the most promising applications of HTS bulks. In such a system, the HTS bulks are always exposed to AC external magnetic field, which is generated by the inhomogeneous surface magnetic field of the NdFeB guideway. In our previous work, we studied the guidance force decay of the YBCO bulk over the NdFdB guideway used in the High-temperature superconducting maglev vehicle system with the application of the AC external magnetic field, and calculated the guidance force decay as a function of time based on an analytic model. In this paper, we investigated the influence of the critical current density on the guidance force decay of HTS bulk exposed to AC field perturbation in the maglev vehicle system and try to adopt a method to suppress the decay. From the results, it was found that the guidance force decay rate was higher for the bulk with lower critical current density. Therefore, we could suppress the guidance force decay of HTS bulk exposed to AC external magnetic field perturbation in the maglev vehicle system by improving critical current density of the bulk.

  13. A comparative study of the density of defect states in bulk samples and thin films of glassy Se$_{90}$Sb$_{10}$

    Indian Academy of Sciences (India)

    KUMAR ANJANI; DWIVEDI PRABHAT K; SHUKLA R K; KUMAR A

    2016-05-01

    The present paper reports the comparative study of density of defect states (DOS) between bulk samples and thin films of glassy Se$_{90}$Sb$_{10}$. These glasses have been prepared by the quenching technique. Thin films of these glasses have been prepared by vacuum evaporation technique. Space-charge-limited conduction (SCLC) has been measured at different temperatures.The density of localized states near Fermi level is calculated by fitting the data to the theory of SCLC for the case of uniform distribution of localized states for bulk as well as for thin films. A comparison has been made between the density of states calculated in these two cases.

  14. Short communication: Methicillin-resistant Staphylococcus aureus in bulk tank milk of dairy cows and effect of swine population density.

    Science.gov (United States)

    Locatelli, C; Cremonesi, P; Bertocchi, L; Zanoni, M G; Barberio, A; Drigo, I; Varisco, G; Castiglioni, B; Bronzo, V; Moroni, P

    2016-03-01

    The methicillin-resistant Staphylococcus aureus (MRSA) has recently frequently been reported in dairy cattle, usually with low prevalence. The livestock-associated MRSA (LA-MRSA) ST398 is especially involved in cases of subclinical and clinical mastitis. Swine carry LA-MRSA without clinical symptoms and are considered its reservoir and shedder. People exposed to swine are particularly at risk of LA-MRSA colonization. Environments with relevant livestock density are a demonstrated risk factor for humans to be carriers of a LA-MRSA. This work investigated dairy farms located in an area with a high livestock density, mainly represented by swine. Bulk tank milk samples from 224 dairy farms were collected, and their status was defined as MRSA-positive or MRSA-negative based on culture on chromogenic medium. The number of fattening swine and of fattening swine herds was calculated in an area of 3 km around each dairy farm through georeferencing. The probability of a Staphylococcus aureus-positive dairy farm to be MRSA positive based on the extent of potential infective pressure due to swine density was calculated. Both the number of swine herds and the number of swine were associated with the MRSA status of dairy herds. The 9 MRSA isolated were typed by multi-locus sequence typing and spa-typing, and characterized for their virulence factors and antimicrobial resistance profiles. The ST and spa-types detected are consistent with those present in the Italian swine population. Virulence and resistance profiles are mostly consistent with the types detected. This work provides the first evidence of the epidemiological challenge exerted by the density of the swine population on MRSA in dairy cows. PMID:26805972

  15. Developing a Penetrometer-Based Mapping System for Visualizing Silage Bulk Density from the Bunker Silo Face

    Directory of Open Access Journals (Sweden)

    Menghua Li

    2016-07-01

    Full Text Available For silage production, high bulk density (BD is critical to minimize aerobic deterioration facilitated by oxygen intrusion. To precisely assess packing quality for bunker silos, there is a desire to visualize the BD distribution within the silage. In this study, a penetrometer-based mapping system was developed. The data processing included filtering of the penetration friction component (PFC out of the penetration resistance (PR, transfer of the corrected penetration resistance (PRc to BD, incorporation of Kriged interpolation for data expansion and map generation. The experiment was conducted in a maize bunker silo (width: 8 m, middle height: 3 m. The BD distributions near the bunker silo face were represented using two map groups, one related to horizontal- and the other to vertical-density distribution patterns. We also presented a comparison between the map-based BD results and core sampling data. Agreement between the two measurement approaches (RMSE = 19.175 kg·m−3 demonstrates that the developed penetrometer mapping system may be beneficial for rapid assessment of aerobic deterioration potential in bunker silos.

  16. Developing a Penetrometer-Based Mapping System for Visualizing Silage Bulk Density from the Bunker Silo Face.

    Science.gov (United States)

    Li, Menghua; Jungbluth, Kerstin H; Sun, Yurui; Cheng, Qiang; Maack, Christian; Buescher, Wolfgang; Lin, Jianhui; Zhou, Haiyang; Wang, Zhongyi

    2016-07-05

    For silage production, high bulk density (BD) is critical to minimize aerobic deterioration facilitated by oxygen intrusion. To precisely assess packing quality for bunker silos, there is a desire to visualize the BD distribution within the silage. In this study, a penetrometer-based mapping system was developed. The data processing included filtering of the penetration friction component (PFC) out of the penetration resistance (PR), transfer of the corrected penetration resistance (PRc) to BD, incorporation of Kriged interpolation for data expansion and map generation. The experiment was conducted in a maize bunker silo (width: 8 m, middle height: 3 m). The BD distributions near the bunker silo face were represented using two map groups, one related to horizontal- and the other to vertical-density distribution patterns. We also presented a comparison between the map-based BD results and core sampling data. Agreement between the two measurement approaches (RMSE = 19.175 kg·m(-3)) demonstrates that the developed penetrometer mapping system may be beneficial for rapid assessment of aerobic deterioration potential in bunker silos.

  17. Magnetic properties and critical current density of bulk MgB2 polycrystalline with Bi-2212 addition

    International Nuclear Information System (INIS)

    Bulk samples of MgB2 were prepared with 0, 3, 5, and 10 wt% Bi2Sr2CaCu2O8 (Bi-2212) particles, added using a simple solid-state reaction route in order to investigate the effect of inclusions of a material with higher Tc than the superconducting matrix. The density, diamagnetic signal, and critical current density, Jc, of the samples change significantly with the doping level. It is found that Jc is significantly enhanced by the Bi-2212 addition. Microstructural analysis indicates that a small amount of Bi-2212 is decomposed into Cu2O and other impurity phases while a significant amount of unreacted Bi-2212 particles remains in MgB2 matrix, and these act as effective pinning centres for vortices. The enhanced pinning force is mainly attributable to these highly dispersed inclusions inserted in the MgB2 grains. Despite the effectiveness of the high-Tc inclusions in increasing superconducting critical currents in our experiment, our results seem to demonstrate the superiority of attractive centres over repulsive ones. A pinning mechanism is proposed to account for the contribution of this type of pinning centre in MgB2 superconductors. (rapid communication)

  18. Developing a Penetrometer-Based Mapping System for Visualizing Silage Bulk Density from the Bunker Silo Face

    Science.gov (United States)

    Li, Menghua; Jungbluth, Kerstin H.; Sun, Yurui; Cheng, Qiang; Maack, Christian; Buescher, Wolfgang; Lin, Jianhui; Zhou, Haiyang; Wang, Zhongyi

    2016-01-01

    For silage production, high bulk density (BD) is critical to minimize aerobic deterioration facilitated by oxygen intrusion. To precisely assess packing quality for bunker silos, there is a desire to visualize the BD distribution within the silage. In this study, a penetrometer-based mapping system was developed. The data processing included filtering of the penetration friction component (PFC) out of the penetration resistance (PR), transfer of the corrected penetration resistance (PRc) to BD, incorporation of Kriged interpolation for data expansion and map generation. The experiment was conducted in a maize bunker silo (width: 8 m, middle height: 3 m). The BD distributions near the bunker silo face were represented using two map groups, one related to horizontal- and the other to vertical-density distribution patterns. We also presented a comparison between the map-based BD results and core sampling data. Agreement between the two measurement approaches (RMSE = 19.175 kg·m−3) demonstrates that the developed penetrometer mapping system may be beneficial for rapid assessment of aerobic deterioration potential in bunker silos. PMID:27399703

  19. Optimization of sintering conditions in bulk MgB{sub 2} material for improvement of critical current density

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, M., E-mail: miryala1@shibaura-it.ac.jp [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Nozaki, K.; Kobayashi, H. [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Zeng, X.L.; Koblischka-Veneva, A.; Koblischka, M.R. [Experimental Physics, Saarland University, P.O. Box 151150, 66041 Saarbrücken (Germany); Inoue, K.; Murakami, M. [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan)

    2015-11-15

    The present investigation focuses on methods to further improve the J{sub c} values of disk-shaped bulk MgB{sub 2} superconductors by optimizing the sintering conditions. We prepared two sets of bulk MgB{sub 2} material from commercial high-purity powders of Mg metal and amorphous B using a single-step solid-state reaction process. To optimize the sintering time, a set of samples was sintered at 775 °C with sintering duration ranging between 1 and 10 h (pure Ar atmosphere). A second set of samples was produced similarly at 775, 780, 785, 795, 800 and 805 °C (3 h, pure argon atmosphere). X-ray diffraction analysis showed that both sets of samples were single phase MgB{sub 2}. Magnetization measurements confirmed a sharp superconducting transition with T{sub c,onset} ≈ 38.2 K–38.8 K. The critical current density (J{sub c}) values for MgB{sub 2} samples produced for 1 h were the highest in all processed materials, i.e., the high J{sub c} value of 270,000 A/cm{sup 2} and 125,000 A/cm{sup 2} (20 K, self-field and 1 T) were achieved in the sample produced at 775 °C, without any additional doping. In contrast, the second series of samples clearly indicated that at 805 °C (3 h) the highest J{sub c} of 245,000 A/cm{sup 2} and 110,000 A/cm{sup 2} (20 K, self-field and 1 T) were achieved. AFM and EBSD observations indicated that largest amount of fine grains do exist in the sample sintered at 775 °C, but the narrowest distribution of grains does exist in the sample sintered at 800 °C. The present results clearly demonstrate a strong relation between the microstructure and the pinning performance. The optimization of the sintering conditions is crucial to improve the performance of bulk MgB{sub 2} samples. - Highlights: • We had successfully improved the performance of sintered, pure bulk MgB{sub 2} materials. • EBSD observations clarified that the grain sizes are in the 100–500 nm range. • The high J{sub c} value at 20 K, 0 T and 1 T are 2.70 × 10{sup 5} A

  20. AB-INITIO STUDY OF BULK MODULUS AND CHARGE DENSITY OF CUBIC SrMO3 PEROVSKITES (M = Ti, Zr, Mo, Rh, Ru

    Directory of Open Access Journals (Sweden)

    AVINASH DAGA

    2012-03-01

    Full Text Available Bulk modulus & charge density of cubic SrMO3 perovskites (M = Ti, Zr, Mo, Rh & Ru have been investigated systematically using the first principle density functional calculations. Local density approximation (LDAmethod has been used to compute the two quantities for five perovskites. It is found that the calculated bulk modulus for all the transition metal oxides are in good agreement with the available experimental data and with other theoretical results previously reported in the literature. ABINIT computer code is used to carry out all the calculations. Charge density plots for all the five cubic SrMO3 perovskites have been drawn using MATLAB. The maximum and minimum values of charge density along with the corresponding reduced coordinates are reported for all the perovskites.

  1. Development of bulk density, total C distribution and OC saturation in fine mineral fractions during paddy soil evolution

    Science.gov (United States)

    Wissing, Livia; Kölbl, Angelika; Cao, Zhi-Hong; Kögel-Knabner, Ingrid

    2010-05-01

    Paddy soils are described as important accumulator for OM (Zhang and He, 2004). In southeast China, paddy soils have the second highest OM stocks (Zhao et al, 1997) and thus a large proportion of the terrestrial carbon is conserved in wetland rice soils. The paddy soil management is believed to be favorable for accumulation of organic matter, as its content in paddy soils is statistically higher than that of non-paddy soils (Cai, 1996). However, the mechanism of OM storage and the development of OM distribution during paddy soil evolution is largely unknown. The aim of the project is to identify the role of organo-mineral complexes for the stabilization of organic carbon during management-induced paddy soil formation in a chronosequence ranging from 50 to 2000 years of paddy soil use. The soil samples were analysed for bulk density, total organic carbon (TOC) and total inorganic carbon (TIC) concentrations of bulk soils and the concentration of organic carbon as well as the organic carbon stocks of physical soil fractions. First results indicate distinctly different depth distributions between paddy and non-paddy (control) sites. The paddy soils are characterized by relatively low bulk densities in the puddled layer (between 0.9 and 1.3 g cm-3) and high values in the plough pan (1.4 to 1.6 g cm-3) and the non-paddy soils by relatively homogeneous values throughout the profiles (1.3 to 1.4 g cm-3). In contrast to the carbonate-rich non-paddy sites, we found a significant loss of carbonates during paddy soil formation, resulting in decalcification of the upper 20 cm after 100 yr of paddy soil use, and decalcification of the total soil profile in 700, 1000 and 2000 yr old paddy soils. The calculation of the organic carbon stocks of each horizon indicate that paddy sites always have higher values in topsoils compared to non-paddy sites, and show increasing values with increasing soil age. The capacity of fine mineral fractions to preserve OC was calculated according to

  2. Effects of Y211 phase contents on the critical current density Jc and microstructural analysis in YBCO bulk superconductors

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    YBCO bulk superconductors were prepared by the solid state reaction and top-seed-melt-textured growth (TSMTG) process. By using the AC susceptibility measurement, the critical transition temperature Tc of samples is 91.5 K for the highest value, and the transition width ?Tc is less than 1 K. The highest magnetization critical current densities Jc achieved 106 A/cm2 under 5 T at 10 K and 1.35?104 A/cm2 under 2 T at 70 K (H//c), respectively. The results combining the SEM observation indicate that doping of Y211 particles is more effective in improving the growth quality of melt-textured YBCO superconductor and in reducing the micro-cracks of specimens. Doping of Y2O3 powder forms the rod-shaped Y211 particles, but doping of Y211 particles directly to matrix materials forms the spherical Y211 particles mainly. Combining the microstructures with Jc measurements shows that the interfaces are most important on flux bundle pinning, in which the gradient of free energy is larger than that of other place between the Y211 particles and the Y123 matrix materials.

  3. A Peak in Density Dependence of Electron Spin Relaxation Time in n-Type Bulk GaAs in the Metallic Regime

    Institute of Scientific and Technical Information of China (English)

    SHEN Ka

    2009-01-01

    We demonstrate that the peak in the density dependence of electron spin relaxation time in n-type bulk GaAs in the metallic regime predicted by Jiang and Wu[Phys.Rev.B 79 (2009) 125206]has been realized experimentally in the latest work[arXiv:0902.0270]by Krauβ et al.

  4. Implications of Using USDA-NCSS Bulk Density to Estimate Carbon Stocks in Forest Soils Across the Southeastern United States

    Science.gov (United States)

    Bacon, A. R.; Akers, K.; Cucinella, J.; Grunwald, S.; Jokela, E. J.; Markewitz, D.; Laviner, M. A.; Vogel, J. G.; Martin, T.; Fox, T. D.; Kane, M.; Peter, G. F.; Davis, J. M.; Ross, C. W.

    2015-12-01

    Estimates of soil bulk density (Db) are critical for accurate estimates of soil carbon (C) stocks, and thus, greatly influence the balance and interpretation of soil C budgets at plot, regional, and national scales. Large scale soil C investigations in the United States (US) almost always utilize a compilation of more than 20,000 Db observations across the US within the USDA-NRCS National Cooperative Soil Survey (NCSS) database. NCSS observations can be manually extracted as point data and then stratified or modeled by a variety of soil taxonomic, geographic, and environmental factors to estimate Db across large scales. NCSS observations also underpin the popular Soil Survey Geographic (SSURGO) database which provides continuous Db estimates across most of the US. Here, for the first time, we evaluate the precision and accuracy with which NCSS data can estimate forest soil Db across the southeastern United States and explore how using these observations impacts soil C budgets in forests across the region. We analyze and compare nearly 3,000 Db observations from the NCSS database to nearly 1,500 Db observations from the PINEMAP Tier II Network (325 experimental forest plots) across the southeastern US. We model all NCSS observations and 70% of the PINEMAP Tier II observations (a calibration dataset) separately with Random Forest algorithms to create a variety of Db predictive models at 0-10, 10-20, 20-50, and 50-100 cm depths. We validate all models against 30% of the PINEMAP Tier II observations (a validation dataset). As indexed by the mean prediction error (MPE), NCSS observations tend to over predict forest soil Db across the validation dataset by an average of 0.20 g/cc. Incorporating this positive bias of NCSS Db predictions into C stock estimates in the top 100 cm of soil across the PINEMAP Tier II network inflates C stock estimates by an average of 13 Mg/ha. Our findings identify significant potential for NCSS observations to over predict soil Db, and thus

  5. The effect of wetting and drying cycles on soil chemical composition and their impact on bulk density evaluation

    International Nuclear Information System (INIS)

    The gamma-ray attenuation technique has been applied successfully in several areas of knowledge such as medicine, industry, chemistry, biology, agriculture and so on. Before the technique application it is important to know the probability of gamma photons interaction with the matter. The linear attenuation coefficient (k) measures the probability per unit length of a photon to be absorbed or scattered while interacting with a sample. k represents the sum of several individual attenuation coefficients due mainly to the photoelectric absorption, coherent and incoherent scatterings and pair production. Soil is characterized as a three phase system composed by solid, liquid and gaseous phases. It is known that for a given photon energy the mass attenuation coefficient (μ) is directly related to the chemical composition of the soil. As a consequence by using the mixture rule, in which (μ) is calculated by adding the products of mass attenuation coefficients and the contents of the chemical components of the soil, it is possible to obtain a theoretical (μ) value. A possible cause of chemical composition changes in soil is the application of repeated wetting and drying (W-D) cycles. Another consequence of these changes in the chemical composition of the soil can be alterations in its (μ). This result can affect how well the gamma-ray attenuation or computed tomography (CT) techniques can determine soil bulk density (ds) or porosity (φ) when samples are submitted to W-D cycles. In this work the soil elemental (oxides) composition variation of three Brazilian soils submitted to the application of W-D cycles was measured in order to evaluate possible changes in the calculated μ as a function of the cycles. Measurements of μ by using radioactive sources of 241Am and 137Cs were also performed. Gamma-ray CT was used as a tool to evaluate the impact of changes in μ induced by the cycles in determinations of ds. The measured and calculated values of μ presented good

  6. Bulk densities and porosities of Cenozoic and Cretaceous basin-filling strata and Cretaceous and older basement rocks, Los Angeles Basin, California, determined from measurements of core samples

    Science.gov (United States)

    Beyer, L.A.; McCulloh, T.H.

    1998-01-01

    This report describes and provides a digital data file of selected bulk properties of subsurface rocks sampled in and around Los Angeles basin, California. Selected properties include measured dry bulk density (range 0.78 to 3.01 g/cm3), measured or estimated grain (matrix) density, calculated water saturated bulk density (range 1.47 to 3.01 g/cm3), calculated total porosity (range 0 to 69 porosity percent), geologic age, and lithology. Most of the rocks are conventional core samples taken from wells drilled by the petroleum industry. A small percentage of the core samples are from shallow borings. Rocks studied range in age from pre-Cambrian (?) to Recent and include sedimentary (98.8%), and volcanic, metamorphic and intrusive (1.2%) samples. Core samples studied were taken from measured drillhole depths that range from 35 to 20,234 ft (11 to 6,167 m). Version 1.0 of the data base (dated June 1998) contains information for 7378 samples from 234 wells, including two redrilled wells. This report/data base can be accessed on U. S. Geological Survey servers at http://geopubs.wr.usgs.gov/open-file/of98-788. Periodic additions to the on-line data base will be provided as new data is gathered.

  7. Superior critical current density obtained in MgB2 bulks via employing carbon-coated boron and minor Cu addition

    Science.gov (United States)

    Peng, Junming; Liu, Yongchang; Ma, Zongqing; Shahriar Al Hossain, M.; Xin, Ying; Jin, Jianxun

    2016-09-01

    High performance Cu doped MgB2 bulks were prepared by an in-situ method with carbon-coated amorphous boron as precursor. It was found that the usage of carbon-coated boron in present work leads to the formation of uniformly refined MgB2 grains, as well as a high level of homogeneous carbon doping in the MgB2 samples, which significantly enhance the Jc in both Cu doped and undoped bulks compared to MgB2 bulks with normal amorphous boron precursor. Moreover, minor Cu can service as activator, and thus facilitates the growth of MgB2 grains and improves crystallinity and grain connectivity, which can bring about the excellent critical current density (Jc) at self fields and low fields (the best values are 7 × 105 A/cm2 at self fields, and 1 × 105 A/cm2 at 2 T, 20 K, respectively). Simultaneously, minor Cu addition can reduce the amount of MgO impurity significantly, also contributing to the improvement of Jc at low fields. Our work suggests that Cu-activated sintering combined with employment of carbon-coated amorphous boron as precursor could be a promising technique to produce practical MgB2 bulks or wires with excellent Jc on an industrial scale.

  8. Gamma-ray yield dependence on bulk density and moisture content of a sample of a PGNAA setup. A Monte Carlo study

    International Nuclear Information System (INIS)

    Monte Carlo calculations were carried out to study the dependence of γ-ray yield on the bulk density and moisture content of a sample in a thermalneutron capture-based prompt gamma neutron activation analysis (PGNAA) setup. The results of the study showed a strong dependence of the γ-ray yield upon the sample bulk density. An order of magnitude increase in yield of 1.94 and 6.42 MeV prompt γ-rays from calcium in a Portland cement sample was observed for a corresponding order of magnitude increase in the sample bulk density. On the contrary the γ-ray yield has a weak dependence on sample moisture content and an increase of only 20% in yield of 1.94 and 6.42 MeV prompt γ-rays from calcium in the Portland cement sample was observed for an order of magnitude increase in the moisture content of the Portland cement sample. A similar effect of moisture content has been observed on the yield of 1.167 MeV prompt γ-rays from chlorine contaminants in Portland cement samples. For an order of magnitude increase in the moisture content of the sample, a 7 to 12% increase in the yield of the 1.167 MeV chlorine γ-ray was observed for the Portland cement samples containing 1 to 5 wt.% chlorine contaminants. This study has shown that effects of sample moisture content on prompt γ-ray yield from constituents of a Portland cement sample are insignificant in a thermal-neutrons capture-based PGNAA setup. (author)

  9. Effects of bulk density of steam-flaked corn in diets containing wet corn gluten feed on feedlot cattle performance, carcass characteristics, apparent total tract digestibility, and ruminal fermentation.

    Science.gov (United States)

    Ponce, C H; Domby, E M; Anele, U Y; Schutz, J S; Gautam, K K; Galyean, M L

    2013-07-01

    The effects of varying bulk density of steam-flaked corn (SFC) in diets containing wet corn gluten feed (WCGF; Sweet Bran; Cargill Corn Milling, Blair, NE) have not been defined. In Exp. 1, yearling steers (n = 108; initial BW = 367 ± 1.18 kg) were housed in 27 pens (4 steers/pen) and received 1 of 3 different SFC bulk density treatments in a randomized complete block design. Bulk density treatments were 283, 335, or 386 g/L SFC in diets containing 25% WCGF (% of DM). Steers were fed once daily to provide ad libitum access to feed for an average of 163 d. For a 5-d period before d 70 of the experiment, DMI was measured, and fecal samples were collected from each pen for measurement of nutrient digestibility using dietary acid insoluble ash as a marker. Varying bulk densities of SFC did not affect (P ≥ 0.233) overall DMI, ADG, or G:F on a live- or carcass-adjusted basis. Dressing percent and LM area increased linearly (P ≤ 0.05) as bulk density increased, but other carcass traits were not affected by treatments. Intake of DM, OM, and CP during the 5-d digestion phase did not differ among bulk densities; however, starch intake increased linearly (P = 0.004) as bulk density of SFC increased. Digestibility of DM, OM, and CP tended (P ≤ 0.065) to decrease and starch digestibility decreased (P = 0.002) linearly as bulk density of SFC increased. In Exp. 2, a 3 × 3 Latin square design was used for collection of ruminal fluid from 3 ruminally cannulated Jersey steers adapted to the same diets used in Exp. 1. Bulk density did not affect NH3 concentrations, VFA molar proportions, ruminal fluid osmolality, and IVDMD of the diets. Total gas production increased linearly (P = 0.003) as bulk density of SFC increased from 283 to 335 g/L, but it decreased (P = 0.002) at 386 g/L. Present data suggest that bulk density can be increased up to 386 g/L in finishing diets containing 25% (DM basis) WCGF without affecting cattle performance and with limited effects on ruminal

  10. Effect of Mg content on the density and critical properties of in-situ reacted MgB2 bulk superconductor

    International Nuclear Information System (INIS)

    The effects of Mg content on the pore formation, density and critical properties were investigated in in-situ reacted MgB2 superconductors. The Mg1+xB2, (x=-0.2, 0.0, 0.05, 0.3, 1.0) bulk samples with different Mg contents were heat-treated at 900 degrees C for 1 h in an Ar atmosphere. The dimensional changes of a pellet's mass and volume after heat-treatment were measured. After heat-treatment process, the sample mass was decreased by Mg evaporation, but the sample volume was expanded by pore formation at the Mg site; therefore, the apparent density was decreased. Spherical pores the same as Mg particles were developed after heat-treatment in all samples, and the pore density was increased with increasing Mg content. As the x of Mg content was increased to 1.0, the apparent density of Mg1+xB2 samples was decreased due to a relatively larger reduction in a mass change. The critical current density of Mg excessive sample of x=0.05 showed the highest values over the applied magnetic fields because the excessive Mg may compensate Mg loss and enhance grain connectivity

  11. Microwave Dielectric Sensing of Moisture Content in Shelled Peanuts Independent of Bulk Density and with Temperature Compensation

    Science.gov (United States)

    A dielectric method for rapid and nondestructive sensing of moisture content in shelled peanuts from free space measurement of attenuation, phase shift, and their corresponding dielectric properties at microwave frequencies is presented. Results of moisture prediction with three density-independent...

  12. Effects of MgO evolution on the critical current density in bulk MgB{sub 2} containing histidine

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Qi; Liu, Yongchang, E-mail: licmtju@163.com; Ma, Zongqing; Yu, Liming

    2014-01-15

    Highlights: •Histidine is an effective dopant for improving the critical current density. •The dominating pinning effects are provided by nano-scale MgO pinning centers. •MgO performed stronger pinning effects than defects caused by C substitution. •We clarified how to select the amino acid for doping. -- Abstract: Glycine, an amino acid with the simplest composition, was introduced into MgB{sub 2} systems, making great contribution to the enhancement of critical current density in our previous study. Aiming at investigating the effects of histidine, another amino acid with more complicated structure and lower decomposition temperature than glycine, on the superconducting properties of MgB{sub 2}, samples of MgB{sub 2} + x wt.% histidine (with x = 0, 2, 3, 5, and 8) were sintered at 800 °C after mechanical mixing. The best critical current density was obtained in the sample with 2 wt.% histidine addition, owing to the small-sized MgO and C substitution. The sample showed a significant increase in critical current density under high field compared with pure MgB{sub 2}, and this property maintained at a relatively high level under low field as well. However, the growth and agglomeration of MgO with the increasing amount of histidine should be responsible for the tendency of the decrease in the connectivity and critical current density versus doping content. Finally, the conditions that the used amino acid should meet were investigated as a guide for effective amino acid doping.

  13. [Effects of biochar amendment on cropland soil bulk density, cation exchange capacity, and particulate organic matter content in the North China Plain].

    Science.gov (United States)

    Chen, Hong-Xia; Du, Zhang-Liu; Guo, Wei; Zhang, Qing-Zhong

    2011-11-01

    A 3-year field experiment with randomized block design was conducted to study the effects of biochar amendment on the soil bulk density, cation exchange capacity (CEC), and particulate organic matter C (POM-C) and N (POM-N) contents in a high-yielding cropland in the North China Plain. Four treatments were installed, i.e., chemical NPK (CK), chemical NPK plus 2250 kg x hm(-2) of biochar (C1), chemical NPK plus 4500 kg x hm(-2) of biochar (C2), and 750 kg x hm(-2) of biochar-based slow release fertilizer (CN). Comparing with CK, treatments C1 and C2 significantly decreased the bulk density of 0-7.5 cm soil layer by 4.5% and 6.0%, respectively, and the treatments with biochar amendment increased the CEC in 0-15 cm soil layer, with an increment of 24.5% in treatment C2. Biochar amendment also increased the C (POM-C) and N (POM-N) contents in 0-7.5 cm soil layer, e.g., the POM-C and N contents in treatment C1 and C2 were 250% and 85%, and 260% and 120% higher than those of the CK, respectively. After three years of biochar amendment, the soil had obvious improvement in its physical and chemical properties, and played more active roles in soil carbon sequestration and greenhouse gases emission reduction. PMID:22303671

  14. Study of bulk modulus, volume, energy, lattice parameters and magnetic moments in rare earth hexaborides using density functional theory

    International Nuclear Information System (INIS)

    Rare earth hexaborides have unusual combination of properties with metallic conductivity and low work function as well as low volatility at temperatures providing technologically useful thermionic electron current density, micro-beam applications. Hexaborides of the rare-earth elements are considered for applications as wear- and corrosion-resistant hard coatings for decoration of consumer products such as eye-glass frames and wristwatch casings

  15. Modeling target bulk heating resulting from ultra-intense short pulse laser irradiation of solid density targets

    Energy Technology Data Exchange (ETDEWEB)

    Antici, P. [Dipartimento SBAI, Università di Roma ‘‘La Sapienza,’’ Via Scarpa 14-16, 00161 Roma (Italy); INRS-EMT, Varennes, Québec (Canada); Istituto Nazionale di Fisica Nucleare, Via E. Fermi, 40-00044 Frascati (Italy); LULI, École Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France); Gremillet, L. [CEA, DAM, DIF, F-91297 Arpajon (France); Grismayer, T. [GoLP/Instituto de Plasmas e Fusão Nuclear-Laboratório Associado, Instituto Superior Técnico, 1049-001 Lisboa (Portugal); Mora, P. [Centre de Physique Théorique, École Polytechnique, CNRS, 91128 Palaiseau (France); Audebert, P.; Mančic, A.; Fuchs, J. [LULI, École Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France); Borghesi, M.; Cecchetti, C. A. [School of Mathematics and Physics, The Queen' s University, Belfast (United Kingdom)

    2013-12-15

    Isochoric heating of solid-density matter up to a few tens of eV is of interest for investigating astrophysical or inertial fusion scenarios. Such ultra-fast heating can be achieved via the energy deposition of short-pulse laser generated electrons. Here, we report on experimental measurements of this process by means of time- and space-resolved optical interferometry. Our results are found in reasonable agreement with a simple numerical model of fast electron-induced heating.

  16. Enhancement of short-circuit current density in polymer bulk heterojunction solar cells comprising plasmonic silver nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yuzhao; Lin, Xiaofeng; Ou, Jiemei; Chen, Xudong, E-mail: cescxd@mail.sysu.edu.cn, E-mail: stszx@mail.sysu.edu.cn, E-mail: chenyj69@mail.sysu.edu.cn [Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education of China, Sun Yat-sen University, Guangzhou 510275 (China); Qing, Jian; Zhong, Zhenfeng; Zhou, Xiang, E-mail: cescxd@mail.sysu.edu.cn, E-mail: stszx@mail.sysu.edu.cn, E-mail: chenyj69@mail.sysu.edu.cn; Chen, Yujie, E-mail: cescxd@mail.sysu.edu.cn, E-mail: stszx@mail.sysu.edu.cn, E-mail: chenyj69@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Hu, Chenglong [Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, Jianghan University, Wuhan 430056 (China)

    2014-03-24

    We demonstrate that the influence of plasmonic effects based on silver nanowires (Ag NWs) on the characteristics of polymer solar cells (PSCs). The solution-processed Ag NWs are situated at the interface of anode buffer layer and active layer, which could enhance the performance especially the photocurrent of PSCs by scattering, localized surface plasmon resonance, and surface plasmon polaritons. Plasmonic effects are confirmed by the enhancement of extinction spectra, external quantum efficiency, and steady state photoluminescence. Consequently, the short-circuit current density (J{sub sc}) and power conversion efficiency enhance about 24% and 18%, respectively, under AM1.5 illumination when Ag NWs plasmonic nanostructure incorporated into PSCs.

  17. Superior critical current density obtained in MgB2 bulks through low-cost carbon-encapsulated boron powder

    International Nuclear Information System (INIS)

    The unavailability of high quality precursor is encouraging researchers to seek effective ways to fabricate magnesium diboride (MgB2) wire. Herein, cost-effective amorphous boron powder produced through a diborane (B2H6) gas process is investigated for the possibility of further industrial application. A thin carbon layer to encapsulate the boron particles is simultaneously deposited by pyrolysis of hydrocarbon. We found that the carbon-encapsulated amorphous boron has a high upper critical field due to impurity scattering, and thereby, enhanced high-field critical current density

  18. An experimental measurement of the coexistence curve and critical temperature, density and pressure of bulk nuclear matter

    CERN Document Server

    Elliott, J B; Moretto, L G; Phair, L

    2012-01-01

    Infinite, neutron-proton symmetric, neutral nuclear matter has a critical temperature of 17.9+-0.4 MeV, a critical density of 0.06+-0.01 nucleons per cubic fermi and a critical pressure of 0.31+-0.07 MeV per cubic fermi. These values have been obtained from our analysis of data from six different reactions studied in three different experiments: two "compound nuclear" reactions: 58Ni+12C-->70Se and 64Ni+12C-->76Se (both performed at the LBNL 88" Cyclotron) and four "multifragmentation" reactions: 1 GeV/c pi+197Au (performed by the ISiS collaboration), 1 AGeV 197Au+C, 1 AGeV 139La+12C and 1 AGeV 84Kr+12C (all performed by the EOS collaboration). The charge yields of all reactions as a function of excitation energy were fit with a version of Fisher's droplet model modified to account for the dual components of the fluid (i.e. protons and neutrons), Coulomb effects, finite size effects and angular momentum arising from the nuclear collisions.

  19. Tunnel geometry of the subterranean termite Reticulitermes grassei (Isoptera: Rhinotermitidae) in response to sand bulk density and the presence of food

    Institute of Scientific and Technical Information of China (English)

    T(A)NIA NOBRE; LINA NUNES; DAVID E. BIGNELL

    2007-01-01

    The cryptic habits of subterranean termites restricts detailed analysis of their foraging patterns in situ, but the process is evidently dominated by tunnel constructions connecting the nest with woody resources discovered within the territory of each colony.In this study, tunnel formation and orientation were studied experimentally in the termite taining fine sand as the substratum. The building of exploratory tunnels over a 10-day period and the geometry of the resulting network are described. Fractal analysis showed that tunnel geometry had a fractal dimension, regardless of the total length tunnelled whether foragers encountered the food source or not. The bulk density of the sand in the arenas affected the distances tunnelled, with higher density reducing construction, but did not affect tunnel geometry. Tunnels were not discernibly orientated with respect to the positioning of the food source, even in a situation where termites had failed to find the food source at a distance of less than 50 mm, suggesting that volatiles from wood are not attractants.

  20. Dispersion-Corrected Density Functional Theory Investigations of Structural and Electronic Properties of Bulk MoS2: Effect of Uniaxial Strain.

    Science.gov (United States)

    Nguyen, Chuong V; Hieu, Nguyen N; Nguyen, Duong T

    2015-12-01

    Strain-dependent structural and electronic properties of MoS2 materials are investigated using first principles calculations. The structural and electronic band structures of the MoS2 with relaxed unit cells are optimized and calculated by the dispersion-corrected density functional theory (DFT-D2). Calculations within the local density approximation (LDA) and GGA using PAW potentials were also performed for specific cases for the purpose of comparison. The effect of strain on the band gap and the dependence of formation energy on strain of MoS2 are also studied and discussed using the DFT-D2 method. In bulk MoS2, the orbitals shift towards the higher/lower energy area when strain is applied along the z/x direction, respectively. The energy splitting of Mo4d states is in the range from 0 to 2 eV, which is due to the reduction of the electronic band gap of MoS2.

  1. Predicting available water of soil from particle-size distribution and bulk density in an oasis-desert transect in northwestern China

    Science.gov (United States)

    Li, Danfeng; Gao, Guangyao; Shao, Ming'an; Fu, Bojie

    2016-07-01

    A detailed understanding of soil hydraulic properties, particularly the available water content of soil, (AW, cm3 cm-3), is required for optimal water management. Direct measurement of soil hydraulic properties is impractical for large scale application, but routinely available soil particle-size distribution (PSD) and bulk density can be used as proxies to develop various prediction functions. In this study, we compared the performance of the Arya and Paris (AP) model, Mohammadi and Vanclooster (MV) model, Arya and Heitman (AH) model, and Rosetta program in predicting the soil water characteristic curve (SWCC) at 34 points with experimental SWCC data in an oasis-desert transect (20 × 5 km) in the middle reaches of the Heihe River basin, northwestern China. The idea of the three models emerges from the similarity of the shapes of the PSD and SWCC. The AP model, MV model, and Rosetta program performed better in predicting the SWCC than the AH model. The AW determined from the SWCCs predicted by the MV model agreed better with the experimental values than those derived from the AP model and Rosetta program. The fine-textured soils were characterized by higher AW values, while the sandy soils had lower AW values. The MV model has the advantages of having robust physical basis, being independent of database-related parameters, and involving subclasses of texture data. These features make it promising in predicting soil water retention at regional scales, serving for the application of hydrological models and the optimization of soil water management.

  2. Comet formation in collapsing pebble clouds. What cometary bulk density implies for the cloud mass and dust-to-ice ratio

    CERN Document Server

    Lorek, S; Lacerda, P; Blum, J

    2016-01-01

    Comets are remnants of the icy planetesimals that formed beyond the ice line in the Solar Nebula. Growing from micrometre-sized dust and ice particles to km-sized objects is, however, difficult because of growth barriers and time scale constraints. The gravitational collapse of pebble clouds that formed through the streaming instability may provide a suitable mechanism for comet formation. We study the collisional compression of cm-sized porous ice/dust-mixed pebbles in collapsing pebble clouds. For this, we developed a collision model for pebbles consisting of a mixture of ice and dust, characterised by their dust-to-ice mass ratio. Using the final compression of the pebbles, we constrain combinations of initial cloud mass, initial pepple porosity, and dust-to-ice ratio that lead to cometesimals which are consistent with observed bulk properties of cometary nuclei. We find that observed high porosity and low density of ~0.5 g/cc of comet nuclei can only be explained if comets formed in clouds with mass appro...

  3. Effects of graphite doping on critical current density and microstructure of MgB2 bulks by an improved Mg-diffusion method

    International Nuclear Information System (INIS)

    abstract: A series of graphite-doped MgB2 bulks with high density have been successfully prepared by an improved Mg-diffusion method in ambient pressure. The effects of graphite doping on lattice parameters, Tc, Jc and microstructure of MgB2 have been investigated. The results show that compared to the nano-C-doped or CNTs-doped MgB2, C is not easy to substitute B in graphite-doped MgB2. However, at the same C content, the graphite-doped MgB2 has a higher Jc. At 10 K and self-field, the Jc for MgB1.985C0.015 reaches 0.58 MA/cm2. For the MgB1.945C0.055, at 5 K, 7 T and 10 K, 6 T the Jc achieves 10,000 A/cm2 which is two orders of magnitude higher than that for the undoped sample. In addition to improving electron scattering and intergranular connectivity, the unreacted graphite in the graphite-doped MgB2 is proposed to be responsible to the excellent Jc properties of MgB2 in high fields, due to depressed grain growth and enhanced grain boundary flux pinning

  4. Effects of Bulk Density on Root Growth of High Yield Maize and Their Regulation%土壤容重对高产玉米根系生长的影响及调控研究

    Institute of Scientific and Technical Information of China (English)

    郑存德; 依艳丽; 张大庚; 徐龙超

    2012-01-01

    不同土壤容重不同,其稳定性也不同.土壤容重的变化会引起土壤调节水、气、热能力的变化,提高土壤的自动调节能力可以使土壤肥力水平得以提高并满足植物对生长因子的持续需求.为研究土壤物理性质对玉米高产稳产的影响机理,以耕地棕壤为试验材料,采用盆栽方法,研究不同容重对玉米根系生长指标的影响,并进一步研究了施用不同有机肥量及模拟不同耕作深度对玉米根系生长的调控效果.结果表明:在设计容重范围内,容重增加,根系生长指标都表现为下降,容重大于1.2g/m3时,不同处理根系生长指标差异显著;当容重大于1.3g/cm3时,不同处理根系活力差异显著.施用有机肥对高容重土壤调控效果更好,有机质含量为4%与5%的处理差异减小,低容重土壤在所设计的有机质水平内调控效果也都较好.耕层厚度增加可以提高根系生长参数,但与对照相比,差异不显著.所以,对于紧实结构性较差的土壤,改善其调节能力应该通过增施有机肥的方法,紧实结构较好的土壤考虑使用耕翻的办法.%Soil bulk density is one of the important soil physical properties. Different soil with different soil bulk density and stability, at the same time , soil regulation ability of soil-water, soil-gas, soil-heat capacity changed with unstability of soil bulk density. It can improve soil fertility degree and the continuing demand factors of plant growth if the soil's automatically adaptational ability was enhanced, therefore, it is necessary to research how soil bulk density vary and how to regulate and control it. In order to study the mechanism of the impact of soil physical properties on high and stable yield of maize, this paper, with cultivated brown soil and pot experiment, studied the effect of soil bulk density on maize root growth parameters( root length,root area,root volume) ,furthermore,it studied the result of regulation by

  5. Effects of graphite doping on critical current density and microstructure of MgB{sub 2} bulks by an improved Mg-diffusion method

    Energy Technology Data Exchange (ETDEWEB)

    Pan, X.F. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhao, Y. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia)], E-mail: yshao@home.swjtu.edu.cn; Feng, Y. [Northwest Institute for Nonferrous Metal Research, P.O. Box 51, Xi' an, Shaanxi 710016 (China); Western Superconductivity Technology Company, Xi' an (China); Yang, Y. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia)

    2008-09-15

    abstract: A series of graphite-doped MgB{sub 2} bulks with high density have been successfully prepared by an improved Mg-diffusion method in ambient pressure. The effects of graphite doping on lattice parameters, T{sub c}, J{sub c} and microstructure of MgB{sub 2} have been investigated. The results show that compared to the nano-C-doped or CNTs-doped MgB{sub 2}, C is not easy to substitute B in graphite-doped MgB{sub 2}. However, at the same C content, the graphite-doped MgB{sub 2} has a higher J{sub c}. At 10 K and self-field, the J{sub c} for MgB{sub 1.985}C{sub 0.015} reaches 0.58 MA/cm{sup 2}. For the MgB{sub 1.945}C{sub 0.055}, at 5 K, 7 T and 10 K, 6 T the J{sub c} achieves 10,000 A/cm{sup 2} which is two orders of magnitude higher than that for the undoped sample. In addition to improving electron scattering and intergranular connectivity, the unreacted graphite in the graphite-doped MgB{sub 2} is proposed to be responsible to the excellent J{sub c} properties of MgB{sub 2} in high fields, due to depressed grain growth and enhanced grain boundary flux pinning.

  6. Influence of soft ferromagnetic sections on the magnetic flux density profile of a large grain, bulk Y-Ba-Cu-O superconductor

    OpenAIRE

    Philippe, Matthieu; Ainslie, Mark D.; Wera, Laurent; Fagnard, Jean-François; Dennis, Anthony; Shi, Yunhua; Cardwell, David A.; Vanderheyden, Benoît; Vanderbemden, Philippe

    2015-01-01

    Bulk, high temperature superconductors have significant potential for use as powerful permanent magnets in a variety of practical applications due to their ability to trap record magnetic fields. In this paper, soft ferromagnetic sections are combined with a bulk, large grain Y-Ba-Cu-O (YBCO) high temperature superconductor to form superconductor/ferromagnet (SC/FM) hybrid structures. We study how the ferromagnetic sections influence the shape of the profile of the trapped magnetic induction ...

  7. 堆积密度对炼焦煤膨胀性能影响的研究%Effect of bulk density of coking coal on Audibert-Arnu dilatation

    Institute of Scientific and Technical Information of China (English)

    白金锋; 李娜; 钟祥云; 张雅茹; 徐君; 奚白; 刘洪春

    2012-01-01

    研究了典型七台河新建1/3焦煤和桃山焦煤在不同堆积密度条件下的Audibert-Arnu膨胀性能及Gb因子变化规律。结果表明:煤料堆积密度提高后,其开始软化温度增加,开始膨胀温度降低;当煤料堆积密度从0.88t/m3增加到1.19t/m3时,新建煤1/3焦煤的开始软化温度增加30℃,桃山焦煤增加14℃,新建1/3焦煤的开始膨胀温度降低19℃,桃山焦煤降低15℃;同时,随煤料堆积密度提高,其最大膨胀度增加,膨胀温度区间也呈增加趋势;Gb因子随煤料堆积密度提高而呈增加规律。%The coal bulk density significantly influences the coal dilatation during the coking process. Based on typical samples of Xinjian 1/3 and Taoshan coking coals from Qitaihe( Heilongjiang Province), the effects of bulk density on the Audibert-Arnu dilatation behavior including initial softening temperature, dilatation starting temperature, maximum dilatation and variation of Gb factor were investigated. Experimental results demonstrate that higher coal bulk density improves the initial soften temperature but decreases the dilatation starting temperature. When the bulk density is in- creased from 0. 88 to 1.19 t/m3 ,the initial soften temperature of Xinjian coal and Taoshan coal is increased by 30 and 14℃, respectively. But the starting dilatation temperature of Xinjian coal and Taoshan coal is lowered by 19 and 15 ℃ ,respectively. Higher bulk density clearly increases the percent dilatation and its temperature range. Gh factor of the coals is also increased with the coal bulk density.

  8. Comparação de métodos de medida da densidade do solo = Comparison of methods to evaluate soil bulk density.

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Pires

    2011-01-01

    Full Text Available A densidade do solo (ds tem sido usada como um parâmetro importante de caracterização física da estrutura do solo e como um indicador de sua compactação. Este trabalho teve como objetivo comparar os valores de ds obtidos através de métodos convencionais, como torrão parafinado (MTP e anel volumétrico (MAV, e nucleares, como tomografia computadorizada (MTC, atenuação gama (MAG e sonda de superfície nêutron-gama (MSN. Foram feitas coletas de amostras em áreas submetidas às práticas de manejo de plantio convencional e plantio direto. Para as análises pelos MAV, MTP, MTC e MAG foram coletadas 16 amostras na camada superficial do solo e para o MSN foramrealizadas leituras em 16 pontos distintos ao longo da área experimental. Os maiores valores de ds foram obtidos para os MTP, MTC e MAG (plantio convencional não diferindo estatisticamente entre si. Os menores valores de ds foram obtidos para os MSN e MAV não diferindo estatisticamente entre si. Com relação ao plantio direto foram comparados somente os MAV e MAG com os valores de ds diferindo estatisticamente entre si.Soil bulk density (ds is traditionally used as an indicator of soil structure and soil compaction. The objective of this work was to compare ds values obtained through conventional methods like paraffinsealed clod (MTP and volumetric ring (MAV, and nuclear methods like computerized tomography (MTC, gamma-ray attenuation (MAG and neutron-gamma surface gauge (MSN. Soil samples were collected in areas under conventional tillage and no-tillage systems. Sixteen samples were collected in the soil surface layer for the analyses by the MAV, MTP, MTC, and MAG. For the MSN, sixteen readings were carried out throughout the experimental area. The highest ds values for the conventional tillage system were obtained for the MTP, MPC, and MAG, without significant differences. Also the statistic test indicates that the lowest ds values obtained for the MSN and MAV did not differ

  9. High-Resolution Sedimentation Rates at IODP Sites U1424 and U1427 since the late Pliocene from spectral-analyzing GRA Bulk Density and RGB Color Profiles

    Science.gov (United States)

    Gorgas, Thomas; Irino, Tomohisa; Tada, Ryuji

    2016-04-01

    Sedimentation Rates (SRs) for IODP Sites U1424 (lat/lon coordinates: 40o11.40'N, 138o13.90'E; water depth: 2808 mbsl) and U1427 (lat/lon coordinates: 35o57.92'N, 134o26.06'E; water depth: 330 mbsl) were calculated by performing spectral analysis in the depth domain on both RGB color and Gamma-Ray-Attenuation (GRA) bulk density data. Inversion and integration of SRs versus depth from spectral analysis yielded detailed SR profiles in both time and depth domains. Our results show a greater variability in calculated SRs and differed from those established through coarse-scaled biostratigraphy and paleo-magnetic data. Our data analyses produces pulses of distinct high SRs for certain depth/age intervals at both sites, with time lags for such features possibly due to variable oceanographic conditions near-shore for Site U1427 versus those at Site U1424 further offshore. Both GRA and RGB profiles reveal a distinct periodicity in the waveband of Milankovitch cycles and other prominent periodicities in the 10-to-1ky period range. This observation suggests climate variabilities and trends in SRs responding to insolation patterns during the past 1 Myr at both sites and extending to 4.5 Myr for Site U1424. With only few identified eccentricity (100ky) cycle segments throughout the entire normalized spectral amplitude profile, our high-resolution Age-Depth model was tuned to obliquity (41ky) and precessional (19-23ky) cycles to achieving a strong fit with corresponding low-resolution models based on biostratigraphy, paleo-magnetic and, at least for Site U1424, augmenting volcanostratigraphy data. According to our Age-Depth models, relatively low SRs occur when evolutive amplitude spectra are dominated by periods in the range of obliquity and eccentricity. In contrast, significant SR peaks at both sites often occur when strong precessional amplitudes coexist with all other cycles. Lower SRs at Site U1424 have been interpreted to reflect a decrease in diatom flux and relative

  10. Strong perpendicular magnetocrystalline anisotropy of bulk and the (001) surface of DO22 Mn3Ga: a density functional study

    Science.gov (United States)

    Yun, Won Seok; Cha, Gi-Beom; Gee Kim, In; Rhim, S. H.; Hong, Soon Cheol

    2012-10-01

    Strong perpendicular magnetocrystalline anisotropy (MCA) and low saturation magnetization are found in DO22 Mn3Ga using the full-potential linearized augmented plane wave (FLAPW) method. The ferrimagnetism in the bulk is well preserved in the surfaces of Mn3Ga for two possible terminations, where the perpendicular MCA in the (001) direction is greatly enhanced over the bulk, consistent with experiments. Furthermore, the robustness of MCA with respect to lattice strain and a good lattice match with popular substrates suggest that Mn3Ga can be a good candidate for strain-resistance spintronics applications.

  11. Design of a New Sensor for Determination of the Effects of Tractor Field Usage in Southern Spain: Soil Sinkage and Alterations in the Cone Index and Dry Bulk Density

    OpenAIRE

    Valera, Diego L.; Jesús Gil; Juan Agüera

    2012-01-01

    Variations in sinkage and cone index are of crucial importance when planning fieldwork, and for determining the trafficability of farm machinery. Many studies have highlighted the link between higher values of these parameters and dramatic decreases in crop yield. Variations in the dry bulk density and cone index of clayey soil in Southern Spain were measured following each of five successive passes over the same land with the three types of tractor most widely used in the area (tracked, two-...

  12. Bulk MgB2 superconductor with high critical current density synthesized by self-propagating high-temperature synthesis method

    Institute of Scientific and Technical Information of China (English)

    Feng Wang-Jun; Xia Tian-Dong; Liu Tian-Zuo; Zhao Wen-Jun; Wei Zhi-Qiang

    2005-01-01

    Pure MgB2 bulk samples are successfully synthesized by self-propagating high-temperature synthesis (SHS)method. The experiments show that the best preheating temperature is 250℃, the highest Jc values of the prepared MgB2 reach 1.5×106A/cm2 (10K, 0.5T) and 1.7×106A/cm2 (20K, 0T), and the MgB2 particle sizes range from 2 to 5μm. The advantages of this method are that it is simple, economical and suitable for the manufacture of bulk MgB2 materials on industrial scale.

  13. Bulk undercooling

    Science.gov (United States)

    Kattamis, T. Z.

    1984-01-01

    Bulk undercooling methods and procedures will first be reviewed. Measurement of various parameters which are necessary to understand the solidification mechanism during and after recalescence will be discussed. During recalescence of levitated, glass-encased large droplets (5 to 8 mm diam) high speed temperature sensing devices coupled with a rapid response oscilloscope are now being used at MIT to measure local thermal behavior in hypoeutectic and eutectic binary Ni-Sn alloys. Dendrite tip velocities were measured by various investigators using thermal sensors or high speed cinematography. The confirmation of the validity of solidification models of bulk-undercooled melts is made difficult by the fineness of the final microstructure, the ultra-rapid evolution of the solidifying system which makes measurements very awkward, and the continuous modification of the microstructure which formed during recalescence because of precipitation, remelting and rapid coarsening.

  14. Bulk Nuclear Properties from Reactions

    OpenAIRE

    Danielewicz, P.

    2002-01-01

    Extraction of bulk nuclear properties by comparing reaction observables to results from semiclassical transport-model simulations is discussed. Specific properties include the nuclear viscosity, incompressibility and constraints on the nuclear pressure at supranormal densities.

  15. 天祝高寒草甸土壤容重与孔隙度时空变化研究%Study on spatial-temporal changes of soil bulk density and soil porosity of alpine meadow in Tianzhu

    Institute of Scientific and Technical Information of China (English)

    路远; 张万祥; 孙榕江; 常根柱

    2009-01-01

    The soil physical poperties of 4 types of alpine meadow (Kobresia capillifoli,sedge+grass,grass+forb,Polygonum viviparum) in Tianzhu was studied. The results showed that there was no fixed variation pattern in soil bulk density and soil porosity among different types,while the variation regulation of the soil spatial structure was clear. The soil bulk density increased and soil porosity decreased along with the soil depth. The soil bulk density of semi-artificial pasture was smaller than other three plots.%选取天祝高寒草甸线叶嵩草草地(Kobresia capillifolia pasture)、莎草-禾草草地(sedge-grass pasture)、禾草-杂类草草地(grass-forb semi-artificial pasture)及珠芽蓼草地(Polygonum viviparum pasture)4块样地的土壤为研究对象,通过对其土壤的物理性状取样分析,结果表明:土壤容重与孔隙度随时间无确定的变化规律;土壤空间结构变化规律明显,均表现出土壤容重随土层深度增加而逐渐增大,土壤孔隙度随土层深度增加而逐渐减小的规律.并且禾草-杂类草半人工草地的土壤容重小于其他3个样地,说明其表层土壤孔隙度增大,通气透水性好.

  16. Movimento e inativação do metribuzin em materiais de dois solos, sob diferentes densidades aparentes Movement and inactivation of metribuzin in two soil materials with different bulk densities

    Directory of Open Access Journals (Sweden)

    L.E.F. Fontes

    1980-06-01

    Full Text Available Numa série de ensaios em laboratório e casa-de-vegetação, estudou-se a mobilidade e a inativação do herbicida metribuzin em materiais de um Latossolo e de um Podzólico representativos de duas regiões do Estado de Minas Gerais, em função de diferentes densidades aparentes. Ensaios biológicos foram utilizados para medir a inativação e a mobilidade do metribuzin nos diferentes solos e densidades. A densidade aparente alterou de forma pronunciada a quantidade de herbicida lixiviado através das colunas dos materiais dos solos estudados. Quanto maior a densidade, menor a quantidade de herbicida lixiviado. A quantidade de herbicida que permaneceu biologicamente ativo ao longo da coluna foi diretamente relacionada com a densidade, em cada solo. A mobilidade do metribuzin no material do Latossolo foi maior que no de Podzólico, em consequência de maior atividade coloidal deste.The leaching and inactivation of metribuzin were studied with materials of two mineral soilsat different bulk densities. Plastic tubing of' 7.25 cm diameter and 10 cm height were filled up with different amounts of soil to get different bulk densities. One kg/ha of a.i. of metribuzin placed on the surface are a of the column was le ached through these soil colums using 250 ml of water. The cotyledon disk bioassay method was used to detect the metribuzin leachet. The biological active metribuzin in the soil colunn at different depths, and the inativation abil ity of the soils were determined using the assay with cucumber (Cucumis sativus L. as test-plant. The increase of bulk density reduced the leaching and enhanced the biologically active metribuzin in the soil column. Metribuzin was more mobil in the Red -yellow Lato ssol and more inactivated in the Red-yellow Podzolic soils.

  17. Study of the feasibility and precision in dose calculation with the method of bulk density assignment%容积密度分配法剂量计算可行性研究

    Institute of Scientific and Technical Information of China (English)

    秦颂兵; 周菊英; 龚唯; 吴承骏; 郭建; 陈龙; 詹蔚

    2013-01-01

    Objective To study investigate the dose accuracy that can be achieved with the method of bulk density assignment.Methods Sixteen cases of nasopharyngeal cancer patients and nineteen cases of esophageal cancer patients who accept radiotherapy in our department were selected.The planning CT images with bulk density assignment to different classes of tissues were applied to calculate the dose distributions,and then the resulting dose volume histograms (DVH) of the tumor and organs of risk were compared with the original treatment plan.The paired t-test was taken for dose comparison between two plans.Results The DVH comparison based on the planning CT and the bulk density assignment CT showed good agreements.With nasopharyngeal cancer patients,differences between the two plans about target and normal tissue were less than 1%.With esophageal cancer patients,the dose differences were less than 2%.Conclusion Preliminary results confirm that the bulk density assignment method can be applied to calculate the dose distributions.%目的 评估采用容积密度分配法进行剂量计算的可行性.方法 选取本科放疗的16例鼻咽癌和19例食管癌患者,对定位CT计划进行容积密度分配法重新制作计划,根据靶区和危及器官受量及剂量体积直方图比较新计划与原计划的剂量分布差异.两种计划的剂量比较行配对t检验.结果 采用容积密度分配法后的计划与定位CT计划相比靶区及危及器官剂量差异鼻咽癌患者均<1%、食管癌患者均<2%.结论 初步结果证实采用容积密度分配法可以进行剂量计算.

  18. Effect of wavelengths and excitation density on the optical properties of P3HT: SiNWs bulk heterojunction for photovoltaic applications

    Science.gov (United States)

    Hidouri, T.; Saidi, H.; Amri, C.; Saidi, F.; Bouazizi, A.

    2016-09-01

    In this work, hybrid nano-composite based on poly (3-hexylthiophène) P3HT and silicon nanowires (SiNWs) were prepared by Ag-assisted chemical etching method (MACE) on n-type (100) Si substrate. We study the influence of the power and wavelength excitation on photoluminescence (PL) properties. We note that charge transfer between poly (3-hexylthiophène) and SiNWs is more pronounced using an excitation of 488 nm than 514 nm. This result correlates with the penetration depth found. Luminescence keys as function of excitation density proves an explication of the charge behavior in hybrid structure. A red shift of the PL peak was noted with increasing the excitation density for 488 nm and 514 nm excitation due to the confinement effect.

  19. Laboratory Research of Low Bulk Density CO LTS Catalyst%低密度一氧化碳低温变换催化剂的研究

    Institute of Scientific and Technical Information of China (English)

    周莲凤

    2012-01-01

    Basing on the domestic Cu-based CO LTS catalyst,reduce bulk desity and MeOH yield of the Cu-based CO LTS catalyst was researched in laboratory.The technological route,component,formula and proper manufacture was used on study on the activity,heat resistance and MeOH yield.Composite property was excellent when the ratio of Cu/Zn at 1.0~1.8 of the catalyst.The results showed that the property of the catalyst better than the Commercial domestic Cu-based CO LTS catalyst and could applied in CO LTS with low H2O/C.%在国产铜系一氧化碳低温变换催化剂基础上,进行了降低堆密度和副产甲醇量的研究,通过对制备催化剂技术路线的研究,选择了组成为铜、锌、铝氧化物的混合物,Cu/Zn为1.0~1.8时催化剂综合性能较好,考察了制备的低密度催化剂的活性、耐热性和甲醇的生成量,并与现有工业催化剂进行了对比,结果表明本研究的低变催化剂性能达到了较先进的技术指标,能够在低水碳比条件下使用。

  20. 体积置换法直接测量土壤质量含水率及土壤容重%Volume replacement method for direct measurement of soil moisture and bulk density

    Institute of Scientific and Technical Information of China (English)

    马玉莹; 雷廷武; 张心平; 陈逸欣

    2013-01-01

    Direct measurement of soil moisture and bulk density is the foundation of related research and applications, which is of great importance in such studies and applications as soil mechanics, crop production, irrigation and ecological environments. This paper presents a new method for direct measurement of soil moisture and soil bulk density based on volume replacement, which is equivalent to the conventional oven-dry method. The measurement principle is based on the model of soil three-phase composition, soil particles, water and air. Its volume and mass are partitioned into three fractions of these substances. The initial soil mass is approximately determined by the soil particles and water when the air mass is neglected. The measurement principles are as the follows. The samples used for measurements of moisture content and bulk density were taken by corers of known volumes and were weighted to determine their initial masses before they were filled with water to saturation state to replace all the air-filled spaces in the soil samples. The initial/original weight of the soil sample and that after saturation were used to compute the water mass required to replace the air-filled volume. Under the known soil particle density, the given volume as defined by the corer and the determined air-filled space volume, the original soil water content and soil bulk density can be calculated. An experimental system and the related algorithm procedures were proposed for the direct measurement of water content and soil bulk density. The standard soil corers were used to prepare the soil samples under designed bulk densities. The saturators were used to pre-saturate the soil samples. The samples were dripped with water to ensure their saturation during the measurement. Three soil materials, a clay loam from Yangling of Shaanxi province, a silt loam from Beijing and a red clay from Jiangxi province, were used for the demonstrational experiments to illustrate the measurement

  1. The influence of the partial pressure of air on the extent of surface and bulk grafting during the mutual irradiation of acrylic acid vapour and low-density polyethylene

    International Nuclear Information System (INIS)

    The influence of the partial pressure of air on the extent of grafting during the mutual irradiation (γ-ray) of acrylic acid vapour and low-density polyethylene films has been monitored by ESCA and infra-red spectroscopy. It was found that increasing the pressure at which the reaction tube was sealed from 8 x 10-5 to 2 x 10-4 Torr did not change the extent of bulk grafting but drastically reduced that on the surface, and gave rise to an embedded graft. The surface of the embedded graft is crosslinked. The degree of crosslinking also appears to be dependent on the partial pressure of air (i.e. oxygen). (author)

  2. Design of a new sensor for determination of the effects of tractor field usage in southern Spain: soil sinkage and alterations in the cone index and dry bulk density.

    Science.gov (United States)

    Valera, Diego L; Gil, Jesús; Agüera, Juan

    2012-01-01

    Variations in sinkage and cone index are of crucial importance when planning fieldwork, and for determining the trafficability of farm machinery. Many studies have highlighted the link between higher values of these parameters and dramatic decreases in crop yield. Variations in the dry bulk density and cone index of clayey soil in Southern Spain were measured following each of five successive passes over the same land with the three types of tractor most widely used in the area (tracked, two-wheel drive and four-wheel drive). In addition, sinkage (rut depth) of the running gear was measured using a laser microrelief profile meter. This device, which integrates three sensors, was specifically designed for these experiments, as was an electrical penetrometer to determine the cone index, and both instruments proved reliable and accurate in the field. The main goal of this study was to design, manufacture and test these new devices. The first pass caused most soil alteration when compared to successive passes for all types of tractor tested and soil conditions prevailing during the tests. (Heavier) four-wheel drive tractors were found to cause greater soil damage (sinkage, cone index and dry bulk density) than two-wheel drive and track tractors. There was no statistically significant difference between the two latter types. The greatest alterations were recorded in the top 10 cm of the soil. The results show that soil compaction should be avoided as much as possible. This can be achieved by ensuring that tractors always travel along the same tracks, especially in the wet season. At present these aspects are not considered by farmers in this area. PMID:23202006

  3. Design of a New Sensor for Determination of the Effects of Tractor Field Usage in Southern Spain: Soil Sinkage and Alterations in the Cone Index and Dry Bulk Density

    Directory of Open Access Journals (Sweden)

    Diego L. Valera

    2012-10-01

    Full Text Available Variations in sinkage and cone index are of crucial importance when planning fieldwork, and for determining the trafficability of farm machinery. Many studies have highlighted the link between higher values of these parameters and dramatic decreases in crop yield. Variations in the dry bulk density and cone index of clayey soil in Southern Spain were measured following each of five successive passes over the same land with the three types of tractor most widely used in the area (tracked, two-wheel drive and four-wheel drive. In addition, sinkage (rut depth of the running gear was measured using a laser microrelief profile meter. This device, which integrates three sensors, was specifically designed for these experiments, as was an electrical penetrometer to determine the cone index, and both instruments proved reliable and accurate in the field. The main goal of this study was to design, manufacture and test these new devices. The first pass caused most soil alteration when compared to successive passes for all types of tractor tested and soil conditions prevailing during the tests. (Heavier four-wheel drive tractors were found to cause greater soil damage (sinkage, cone index and dry bulk density than two-wheel drive and track tractors. There was no statistically significant difference between the two latter types. The greatest alterations were recorded in the top 10 cm of the soil. The results show that soil compaction should be avoided as much as possible. This can be achieved by ensuring that tractors always travel along the same tracks, especially in the wet season. At present these aspects are not considered by farmers in this area.

  4. Soil Bulk Density and Porosity in Greenhouse Vegetables Field under the Optimized Fertilization Treatment%优化施肥处理下设施菜地土壤容重与孔隙度的变化

    Institute of Scientific and Technical Information of China (English)

    张宝峰; 曾路生; 李俊良; 陈清

    2013-01-01

    Soil bulk density and porosity influence the bioavailability of soil nutrient and crop growth, and are closely related to the cultivation, fertilization, irrigation and other agricultural management measures. In order to research soil environmental quality and explore the optimal fertilization mode under Greenhouse field conditions, soil bulk density, porosity and soil respiration intensity were studied under the optimized fertilization conditions, with the soil of no chemical fertilizer and manure for control in Shouguang Greenhouse vegetables field planting tomato, and the results showed that, compared with the control, the optimized fertilization treatments improved the soil bulk density and porosity conditions in a certain extent. Such measures reduced the soil bulk density by 3.73%to 14.93%and increased the soil total porosity by 4.18%to 15.79%. In the meantime, the average capillary porosity and the non capillary porosity increased by 8.07%and 8.94%, respectively. Soil respiration intensity enhanced by 23.4%to 34.6%in the root zone and by 9.6%to 106.9%in the non root zone compared with the control. Among them, the treatment with 8 t/hm2 of manure and 4 t/hm2 of straw blending broadcast, and topdressing 150 kg/hm2 of nitrogen in the growth period got the most obvious effect and should be recommended to apply in the production practice. The results also showed that the average soil respiration intensity in root zone was 62.91 mg/(kg·d) with about 1.8 times of 34.45 mg/(kg·d) in the non-root zone. Soil respiration intensity was parabolic relationship to soil bulk density and soil total porosity. When the soil bulk density was about 1.25 g/cm3 and total porosity was about 53%, the soil would have higher respiration intensity.%土壤容重与孔隙度影响土壤养分的有效性及作物生长,与耕作、施肥、灌溉等农业管理措施密切相关。为了研究设施农业条件下土壤环境质量的变化,探索较优施肥

  5. The impact of agriculture terraces on soil organic matter, aggregate stability, water repellency and bulk density. A study in abandoned and active farms in the Sierra de Enguera, Eastern Spain.

    Science.gov (United States)

    Cerdà, Artemi; Burguet, Maria; Keesstra, Saskia; Prosdocimi, Massimo; Di Prima, Simone; Brevik, Erik; Novara, Agata; Jordan, Antonio; Tarolli, Paolo

    2016-04-01

    Soil erosion, land degradation, lack of organic matter, erodible soils, rock outcrops… are a consequence of the human abuse and misuse of the soil resources. And this is a worldwide environmental issue (Novara et al., 2011; Vanlauwe et al., 2015; Musinguzi et al., 2015; Pereira et al., 2015; Mwagno et al., 2016). Agriculture terraces are a strategy to reduce the soil erosion, improve the soil fertility and allow the ploughing (Cerdà et al., 2010; Li et al., 2014). Although this idea is well accepted there are few scientific evidences that demonstrate that soils in the terraced areas are more stable, fertile and sustainable that the soil in non terraced areas. In fact, the ploughing in comparison to the abandoned or not ploughed land results in the soil degradation (Lieskovský and Kenderessy, 2014; Gao et al., 2015; Parras-Alcántara et al., 2014). This is mainly due to the lack of vegetation that increase the surface runoff (Cerdà et al., 1998; Keesstra et al., 2007). And why is necessary to develop also in terraced landscapes soil erosion control strategies (Mekonnen et al., 2015a; Mekonnen et al., 2015b; Prosdocimi et al., 2016). Our objective was to assess the soil organic matter content (Walkley and Black, 1934), the soil bulk density (ring method), the aggregate stabilility (drop impact) and the water repellency (Water Drop Penetration Time test) in four study sites in the Sierra de Enguera. Two sites were terraced: one abandoned 40 years before the measurements and the other still active with olive crops. And two control sites non-terraced. We used the paired plot strategy to compare the impact of terracing and abandonment. At each site we collected randomly 50 soil samples at 0-2 cm, 4-6 and 8-10 cm depth. At each sampling point 100 WDPT measurements where carried out, and one sample for the bulk density, and one for the organic matter, and one for the soil aggregate stability were collected. The soil surface samples shown the largest differences. The

  6. The Incredible Bulk

    CERN Document Server

    Fukushima, Keita; Kumar, Jason; Sandick, Pearl; Yamamoto, Takahiro

    2014-01-01

    Recent experimental results from the LHC have placed strong constraints on the masses of colored superpartners. The MSSM parameter space is also constrained by the measurement of the Higgs boson mass, and the requirement that the relic density of lightest neutralinos be consistent with observations. Although large regions of the MSSM parameter space can be excluded by these combined bounds, leptophilic versions of the MSSM can survive these constraints. In this paper we consider a scenario in which the requirements of minimal flavor violation, vanishing $CP$-violation, and mass universality are relaxed, specifically focusing on scenarios with light sleptons. We find a large region of parameter space, analogous to the original bulk region, for which the lightest neutralino is a thermal relic with an abundance consistent with that of dark matter. We find that these leptophilic models are constrained by measurements of the magnetic and electric dipole moments of the electron and muon, and that these models have ...

  7. The role of a low-energy–density re-scan in fabricating crack-free Al85Ni5Y6Co2Fe2 bulk metallic glass composites via selective laser melting

    International Nuclear Information System (INIS)

    Highlights: • We proposed a re-scan strategy to prevent crack propagation in SLM. • The re-scan should be carried out at a low laser energy density. • The underlying mechanism is through reduction and relief of residual stresses. • Lowered temperature gradient and superplasticity account for reduction of stress. • For the first time, a crack-free BMGCs gear with a large size was produced. - Abstract: In this paper, we have investigated the use of a re-scanning strategy to prevent propagation of macro-cracks during the selective laser melting of an Al85Ni5Y6Co2Fe2 bulk metallic glass composites (BMGCs). These cracks form as a result of the high residual stress caused by the rapid heating and cooling of the material by the laser beam. Unlike crystalline materials, the BMGCs possess a supercooled liquid region in which the residual stress can be relieved by plastic flow. We show that by using a high power initial scan (designed to melt the material) followed by a lower power re-scan (for stress relief) cracking can be prevented. Using this approach, crack-free Al85Ni5Y6Co2Fe2 BMGCs components have been fabricated, including a gear with a diameter ∼25 mm and height ∼10 mm

  8. The impact of agriculture terraces on soil organic matter, aggregate stability, water repellency and bulk density. A study in abandoned and active farms in the Sierra de Enguera, Eastern Spain.

    Science.gov (United States)

    Cerdà, Artemi; Burguet, Maria; Keesstra, Saskia; Prosdocimi, Massimo; Di Prima, Simone; Brevik, Erik; Novara, Agata; Jordan, Antonio; Tarolli, Paolo

    2016-04-01

    Soil erosion, land degradation, lack of organic matter, erodible soils, rock outcrops… are a consequence of the human abuse and misuse of the soil resources. And this is a worldwide environmental issue (Novara et al., 2011; Vanlauwe et al., 2015; Musinguzi et al., 2015; Pereira et al., 2015; Mwagno et al., 2016). Agriculture terraces are a strategy to reduce the soil erosion, improve the soil fertility and allow the ploughing (Cerdà et al., 2010; Li et al., 2014). Although this idea is well accepted there are few scientific evidences that demonstrate that soils in the terraced areas are more stable, fertile and sustainable that the soil in non terraced areas. In fact, the ploughing in comparison to the abandoned or not ploughed land results in the soil degradation (Lieskovský and Kenderessy, 2014; Gao et al., 2015; Parras-Alcántara et al., 2014). This is mainly due to the lack of vegetation that increase the surface runoff (Cerdà et al., 1998; Keesstra et al., 2007). And why is necessary to develop also in terraced landscapes soil erosion control strategies (Mekonnen et al., 2015a; Mekonnen et al., 2015b; Prosdocimi et al., 2016). Our objective was to assess the soil organic matter content (Walkley and Black, 1934), the soil bulk density (ring method), the aggregate stabilility (drop impact) and the water repellency (Water Drop Penetration Time test) in four study sites in the Sierra de Enguera. Two sites were terraced: one abandoned 40 years before the measurements and the other still active with olive crops. And two control sites non-terraced. We used the paired plot strategy to compare the impact of terracing and abandonment. At each site we collected randomly 50 soil samples at 0-2 cm, 4-6 and 8-10 cm depth. At each sampling point 100 WDPT measurements where carried out, and one sample for the bulk density, and one for the organic matter, and one for the soil aggregate stability were collected. The soil surface samples shown the largest differences. The

  9. Soil bulk density and biomass partitioning of Brachiaria decumbens in a silvopastoral system Densidade do solo e partição de biomassa de Brachiaria decumbens em um sistema silvopastoril

    Directory of Open Access Journals (Sweden)

    Domingos Sávio Campos Paciullo

    2010-10-01

    Full Text Available Shade in silvopastoral systems improves the thermal comfort of animals, but it may also affect the pasture productivity and can contribute to soil compaction in the shaded areas due to the increase in the number of animals looking for comfort. The effect of grazing at various distances from tree rows (under the tree canopy, at 6 and at 12 m away from the trees on the soil bulk density and on the aerial and root biomass of Brachiaria decumbens was evaluated in both the dry and the rainy seasons. The study was carried out on an Orthic Ferralsol in a randomized block design with two replications. Tree rows were composed of Eucalyptus grandis and Acacia mangium species, and the paddocks were submitted to a rotational stocking management, using Holstein (Bos taurus × Zebu (Bos indicus heifers. The shade intensity in the pasture decreased with an increasing distance from the tree row. Soil bulk density did not vary with the distance from the tree row, but varied seasonally, being greater in the rainy season (1.47 g cm-3 than in the dry season (1.28 g cm-3. Green forage and root mass, expressed as dry matter, were lower under the tree canopy and were greater in the rainy season. There were decreases of 22.3 and 41.4% in the aerial and root biomasses, respectively, in the tree rows. The greatest shoot/root ratio for B. decumbens under moderate and intensive shading indicates a modification in the forage biomass allocation pattern that favours the aerial development in detriment of the root system.O sombreamento em sistemas silvipastoris concorre para o conforto térmico dos animais; no entanto pode afetar a produção do pasto e contribuir para a compactação do solo, pelo aumento da concentração de animais nas áreas sombreadas. Avaliou-se o efeito da distância do renque de árvores (sob a copa das árvores, 6 e 12 m de distancia das árvores na densidade do solo e na biomassa aérea e de raízes de Brachiaria decumbens, nas épocas seca e chuvosa

  10. Bulk density of an alfisol under cultivation systems in a long-term experiment evaluated with gamma ray computed tomography;Densidade de um planossolo sob sistemas de cultivo por meio da tomografia computadorizada de raios gama

    Energy Technology Data Exchange (ETDEWEB)

    Bamberg, Adilson Luis; Silva, Thiago Rech da, E-mail: adillbamberg@hotmail.co [Universidade Federal de Pelotas (UFPel), RS (Brazil). Faculdade de Agronomia Eliseu Maciel], E-mail: thiago_cccp@hotmail.com; Pauletto, Eloy Antonio; Pinto, Luiz Fernando Spinelli; Lima, Ana Claudia Rodrigues de, E-mail: pauletto@ufpel.edu.b [Universidade Federal de Pelotas (UFPel), RS (Brazil). Faculdade de Agronomia Eliseu Maciel. Dept. de Solos], E-mail: lfspin@ufpel.edu.b, E-mail: anacrlima@hotmail.co, E-mail: Gome, E-mail: Algenor da Silv, E-mail: algenor@cpact.embrapa.b [EMBRAPA, Pelotas, RS (Brazil). Centro de Pesquisa Agropecuaria Clima Temperado. Estacao Experimental Terras Baixas; Timm, Luis Carlos, E-mail: lctimm@ufpel.edu.b [Universidade Federal de Pelotas (UFPel), RS (Brazil). Faculdade de Agronomia Eliseu Maciel. Dept. de Engenharia Rural

    2009-09-15

    The sustainability of irrigated rice (Oryza sativa L.) in lowland soils is based on the use of crop rotation and succession, which are essential for the control of red and black rice. The effects on the soil properties deserve studies, particularly on soil compaction. The objective of this study was to identify compacted layers in an albaqualf under different cultivation and tillage systems, by evaluating the soil bulk density (Ds) with Gamma Ray Computed Tomography (TC). The analysis was carried out in a long-term experiment, from 1985 to 2004, at an experimental station of EMBRAPA Clima Temperado, Capao do Leao, RS, Brazil, in a random block design with seven treatments, with four replications (T1 - one year rice with conventional tillage followed by two years fallow; T2 - continuous rice under conventional tillage; T4 - rice and soybean (Glycine Max L.) rotation under conventional tillage; T5 - rice, soybean and corn (Zea maize L.) rotation under conventional tillage; T6 - rice under no-tillage in the summer in succession to rye-grass (Lolium multiflorum L.) in the winter; T7 - rice under no-tillage and soybean under conventional tillage rotation; T8 - control: uncultivated soil). The Gamma Ray Computed Tomography method did not identify compacted soil layers under no tillage rice in succession to rye-grass; two fallow years in the irrigated rice production system did not prevent the formation of a compacted layer at the soil surface; and in the rice, soybean and corn rotation under conventional tillage two compacted layers were identified (0.0 to 1.5 cm and 11 to 14 cm), indicating that they may restrict the agricultural production in this cultivation system on Albaqualf soils. (author)

  11. New fermions in the bulk

    CERN Document Server

    de Brito, K P S

    2016-01-01

    Spinor fields on 5-dimensional Lorentzian manifolds are classified, according to the geometric Fierz identities that involve their bilinear covariants. Based upon this classification that generalises the celebrated 4-dimensional Lounesto classification of spinor fields, new non-trivial classes of 5-dimensional spinor fields are, hence, found, with important potential applications regarding bulk fermions and their subsequent localisation on brane-worlds. In addition, quaternionic bilinear covariants are used to derive the quaternionic spin density, through the truncated exterior bundle. In order to accomplish a realisation of these new spinors, a Killing vector field is constructed on the horizon of 5-dimensional Kerr black holes. This Killing vector field is shown to reach the time-like Killing vector field at the spatial infinity, through a current 1-form density, constructed with the derived new spinor fields. The current density is, moreover, expressed as the f\\"unfbein components, assuming a condensed for...

  12. 土壤容重对海涂垦区粉砂土水分垂直入渗特征的影响研究%Study on Impact of Soil Bulk Density on Infiltration Properties of Silt Soil in Coastal Reclamation Regions

    Institute of Scientific and Technical Information of China (English)

    佘冬立; 刘营营; 刘冬冬; 徐翠兰; 曲欣; 陈友林; 邓凌云; 俞双恩

    2012-01-01

    为探明土壤容重变异对海涂围垦区粉砂土水分入渗性能及变化过程的影响,该文通过室内土柱一维垂直入渗试验,比较分析了围垦区粉砂土和南京菜地黄棕壤不同容重下土壤水分入渗率、累积入渗量及湿润锋等的动态变化.结果表明:客重对2种试验土壤入渗过程有较大影响,表征土壤入渗能力的稳定入渗速率、累积入渗量和湿润锋深度均随容重增大递减,呈显著负相关关系.模拟2种土壤入渗过程的考斯加科夫模型中,表征初始入渗速率的参数K值随容重增大递减,而表征入渗能力衰减速度的参数α随容重增大未表现出显著差异.简略的Philip入渗方程的幂级数解可以很好地拟合2种土壤湿润锋深度随时间变化过程,拟合的参数λ和x变化规律表明随着容重的增大,基质势梯度、重力作用都呈逐渐减弱的趋势.采用一维代数模型可以较好的模拟粉砂土入渗剖面含水率分布规律,土壤容重越高,模型的理论值越准确.%In order to determine the effects of soil bulk density on infiltration properties of silt soil in coastal reclamation regions, the dynamic changes of infiltration rates, cumulative infiltration, and wetting front of soil water under different bulk density of silt soil and yellow brown soil were explored by one dimension vertical infiltration experiment in this paper. The results showed that soil infiltration processes were greatly affected by soil bulk density. Infiltration capacity indicated by infiltration rate, accumulative infiltration and wetting front depth of the two experimental soils decreased along with increasing soil bulk density. The indexes of infiltration capacity had significantly negative correlation with soil bulk density. For the two experimental soils, the parameter of K in Kostiakov infiltration equations which meant initial infiltration rate decreased along with increasing soil bulk density, but there were not

  13. Effects of subsoil bulk density on root growth and soil enzyme activities during the growth of corn (Zea mays L.)%不同土层容重对玉米根系生长及土壤酶活性的影响

    Institute of Scientific and Technical Information of China (English)

    王群; 赵亚丽; 张学林; 张永恩; 李潮海

    2012-01-01

    The two-year pool-culture and barrel-culture experiments were conducted to study the impacts of subsoil bulk/density on root lenght, root dry weight, soil enzyme activities and yield in corn field on a sandy loam soil at the Experimental Farm of Henan Agricultural University. The results showed that the dynamic changes of root length, root dry weight, soil catalase, invertase, protease, urease, alkaline phosphatase activities and yields were single curve during the growth of corn, and the maximum values of these parameters occurred at the corn silking stage. Root length, root dry weight, yield and its components decreased with increaseing soil bulk density. These enzyme activities decreased with the increasing of both soil bulk density and soil depth. The higher the soil bulk density was the less active the soil enzyme activities were all soil enzyme activities were significantly different among soil bulk densities in the same soil layer, and they were also affected by soil bulk density in the adjacent layers. The bigger the soil bulk density of adjacent layers was the more significant the decrease was. The effect of subsoil bulk density on soil enzyme was more apparant from jointing stage to maturity.%采用微区池栽和桶栽试验,研究了下层(20~40 cm,40 ~ 60 cm)土壤容重改变后,玉米根系生长、产量及生育期间土壤过氧化氢酶、转化酶、蛋白酶、脲酶和碱性磷酸酶活性动态变化规律及其与微生物活性的相关性.结果表明,在玉米生育期内,玉米单株根长度和根干重、土壤过氧化氢酶、转化酶、蛋白酶、脲酶和碱性磷酸酶活性呈单峰曲线,最高值均出现在吐丝期;且随着下层土壤容重增加呈递减趋势.各土层酶活性均随着土层的加深和本土层容重的增大而降低,同时也随着相邻土层容重的增大其降幅加剧;玉米穗粒数、粒重和产量也随着土壤容重的增加而降低.玉米生长期间,土壤酶活性变化受下层

  14. An intrinsic mobility ceiling of Si bulk

    OpenAIRE

    Garcia-Castello, Nuria; Prades, Joan Daniel; Cirera, Albert

    2011-01-01

    We compute by Density Functional Theory-Non Equilibrium Green Functions Formalism (DFT-NEGFF) the conductance of bulk Si along different crystallographic directions. We find a ceiling value for the intrinsic mobility of bulk silicon of $8.4\\cdot10^6 cm^2/V\\cdot s$. We suggest that this result is related to the lowest effective mass of the $$ direction.

  15. Field spatial and temporal patterns of soil water content and bulk density changes Padrões espacial e temporal de mudanças da umidade e densidade do solo no campo

    Directory of Open Access Journals (Sweden)

    Luís Carlos Timm

    2006-02-01

    Full Text Available Soil water content (theta and bulk density (rhos greatly influence important soil and plant processes, such as water movement, soil compaction, soil aeration, and plant root system development. Spatial and temporal variability of theta and rhos during different periods of the year and different phases of crops are of fundamental interest. This work involves the characterization of spatial and temporal patterns of theta and rhos during different climatic periods of year, aiming to verify whether there are significant temporal changes in rhos at the soil surface layer when submitted to wetting and drying cycles. The field experiment was carried out in a coffee plantation, Rhodic Kandiudalf soil, clayey texture. Using a neutron/gamma surface probe, theta and rhos were measured meter by meter along a 200 m spatial transect, along an interrow contour line. During the wet period there was no difference of spatial patterns of theta while during the dry period differences were observed, and can be associated to precipitation events. It was also observed that there are rhos temporal changes at the soil surface along the studied period as a consequence of the in situ wetting and drying cycles.Umidade (teta e densidade do solo (ros influenciam importantes processos no solo e planta tais como: movimento de água, compactação do solo, aeração do solo e desenvolvimento radicular. Baseado neste fato, questões referentes à variabilidade espacial e temporal de teta e ros para diferentes períodos do ano e diferentes fases de desenvolvimento da cultura do café tornam-se de extremo interesse. Este trabalho teve como objetivo caracterizar padrões espaciais e temporais de teta e ros durante diferentes períodos do ano e verificar se existem mudanças temporais significativas de ros na superfície do solo quando submetida a ciclos de umedecimento/secagem. O experimento foi conduzido em campo cultivado com café em um solo classificado como Nitossolo Vermelho

  16. Large area bulk superconductors

    Science.gov (United States)

    Miller, Dean J.; Field, Michael B.

    2002-01-01

    A bulk superconductor having a thickness of not less than about 100 microns is carried by a polycrystalline textured substrate having misorientation angles at the surface thereof not greater than about 15.degree.; the bulk superconductor may have a thickness of not less than about 100 microns and a surface area of not less than about 50 cm.sup.2. The textured substrate may have a thickness not less than about 10 microns and misorientation angles at the surface thereof not greater than about 15.degree.. Also disclosed is a process of manufacturing the bulk superconductor and the polycrystalline biaxially textured substrate material.

  17. Bulk Superconductors in Mobile Application

    Science.gov (United States)

    Werfel, F. N.; Delor, U. Floegel-; Rothfeld, R.; Riedel, T.; Wippich, D.; Goebel, B.; Schirrmeister, P.

    We investigate and review concepts of multi - seeded REBCO bulk superconductors in mobile application. ATZ's compact HTS bulk magnets can trap routinely 1 T@77 K. Except of magnetization, flux creep and hysteresis, industrial - like properties as compactness, power density, and robustness are of major device interest if mobility and light-weight construction is in focus. For mobile application in levitated trains or demonstrator magnets we examine the performance of on-board cryogenics either by LN2 or cryo-cooler application. The mechanical, electric and thermodynamical requirements of compact vacuum cryostats for Maglev train operation were studied systematically. More than 30 units are manufactured and tested. The attractive load to weight ratio is more than 10 and favours group module device constructions up to 5 t load on permanent magnet (PM) track. A transportable and compact YBCO bulk magnet cooled with in-situ 4 Watt Stirling cryo-cooler for 50 - 80 K operation is investigated. Low cooling power and effective HTS cold mass drives the system construction to a minimum - thermal loss and light-weight design.

  18. Densidade de um planossolo sob sistemas de cultivo avaliada por meio da tomografia computadorizada de raios gama Bulk density of an alfisol under cultivation systems in a long-term experiment evaluated with gamma ray computed tomography

    Directory of Open Access Journals (Sweden)

    Adilson Luís Bamberg

    2009-10-01

    lowland soils is based on the use of crop rotation and succession, which are essential for the control of red and black rice. The effects on the soil properties deserve studies, particularly on soil compaction. The objective of this study was to identify compacted layers in an Albaqualf under different cultivation and tillage systems, by evaluating the soil bulk density (Ds with Gamma Ray Computed Tomography (TC. The analysis was carried out in a long-term experiment, from 1985 to 2004, at an experimental station of Embrapa Clima Temperado, Capão do Leão, RS, Brazil, in a random block design with seven treatments, with four replications (T1 - one year rice with conventional tillage followed by two years fallow; T2 - continuous rice under conventional tillage; T4 - rice and soybean (Glycine Max L. rotation under conventional tillage; T5 - rice, soybean and corn (Zea maize L. rotation under conventional tillage; T6 - rice under no-tillage in the summer in succession to rye-grass (Lolium multiflorum L. in the winter; T7 - rice under no-tillage and soybean under conventional tillage rotation; T8 - control: uncultivated soil. The Gamma Ray Computed Tomography method did not identify compacted soil layers under no-tillage rice in succession to rye-grass; two fallow years in the irrigated rice production system did not prevent the formation of a compacted layer at the soil surface; and in the rice, soybean and corn rotation under conventional tillage two compacted layers were identified (0.0 to 1.5 cm and 11 to 14 cm, indicating that they may restrict the agricultural production in this cultivation system on Albaqualf soils.

  19. Bulk chemicals from biomass

    NARCIS (Netherlands)

    Haveren, van J.; Scott, E.L.; Sanders, J.P.M.

    2008-01-01

    Given the current robust forces driving sustainable production, and available biomass conversion technologies, biomass-based routes are expected to make a significant impact on the production of bulk chemicals within 10 years, and a huge impact within 20-30 years. In the Port of Rotterdam there is a

  20. 华北高寒区多年保护性耕作对农田土壤容重的影响%Long-term Effects of Conservation Tillage on Soil Bulk Density in Cropping Zone of Cold Plateau in North China

    Institute of Scientific and Technical Information of China (English)

    王岩; 张静; 刘玉华

    2013-01-01

    In order to protect the soil, reduce wind erosion and ensure the production, explore the suitable conservation tillage model for the alpine area in North China, to provide a theoretical basis to the local crop production. Based on located experiment of different farming methods for 9 years in Zhangbei, the ministry of agriculture field station, and in 2007-2008, the author studied the effect of the no-tillage, reduced tillage and traditional tillage soil bulk density. The results showed that 3 types of farming methods at the seeding stage and harvesting stage both with the highest was no tillage and the lowest was traditional tillage, at the seeding stage the 0-10 cm and 10-20 cm soil bulk density of no-tillage, respectively were 1.65 g/cm3 and 1.81 g/cm3, with traditional tillage were 1.38 g/cm3 and 1.47 g/cm3, at harvesting stage there was no significant change. In cold plateau in North China, the soil bulk density of cropping zone had been influenced obviously by different tillage methods, the traditional tillage and reduced tillage could be a significant reduction in soil bulk density. With the bio-power effect of crop root growth, seeding stage and harvesting stage no tillage and reduced tillage in cropping zone soil bulk density was downward trend, and there was no significant change in traditional tillage.%为了在保护土壤、减抑风蚀的同时,兼顾作物的产量,探索适合华北高寒区的保护性耕作模式,给当地作物生产提供理论依据,在农业部张北野外观测站连续9年不同耕作方式定位研究的基础上,于2007-2009年探讨了免耕、松耕和翻耕对土壤耕层容重的影响.结果表明,3种耕作方式播种期不同耕层土壤容重均以免耕最高,翻耕最低,播前0~10 cm、10~20 cm土壤容重免耕分别为1.65、1.81 g/cm3,翻耕则分别为1.38、1.47 g/cm3,收获期土壤容重差异不明显.华北高寒区不同耕作方式对农田耕层土壤容重具有明显的影响,翻耕和松耕

  1. Bulk materials handling review

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-02-15

    The paper provides details of some of the most important coal handling projects and technologies worldwide. It describes development by Aubema Crushing Technology GmbH, Bedeschi, Cimbria Moduflex, DBT, Dynamic Air Conveying Systems, E & F Services, InBulk Technologies, Nord-Sen Metal Industries Ltd., Pebco Inc, Primasonics International Ltd., R.J.S. Silo Clean (International) Ltd., Takraf GmbH, and The ACT Group. 17 photos.

  2. Development of superconductor bulk for superconductor bearing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chan Joong; Jun, Byung Hyuk; Park, Soon Dong (and others)

    2008-08-15

    Current carrying capacity is one of the most important issues in the consideration of superconductor bulk materials for engineering applications. There are numerous applications of Y-Ba-Cu-O (YBCO) bulk superconductors e.g. magnetic levitation train, flywheel energy storage system, levitation transportation, lunar telescope, centrifugal device, magnetic shielding materials, bulk magnets etc. Accordingly, to obtain YBCO materials in the form of large, single crystals without weak-link problem is necessary. A top seeded melt growth (TSMG) process was used to fabricate single crystal YBCO bulk superconductors. The seeded and infiltration growth (IG) technique was also very promising method for the synthesis of large, single-grain YBCO bulk superconductors with good superconducting properties. 5 wt.% Ag doped Y211 green compacts were sintered at 900 .deg. C {approx} 1200 .deg.C and then a single crystal YBCO was fabricated by an infiltration method. A refinement and uniform distribution of the Y211 particles in the Y123 matrix were achieved by sintering the Ag-doped samples. This enhancement of the critical current density was ascribable to a fine dispersion of the Y211 particles, a low porosity and the presence of Ag particles. In addition, we have designed and manufactured large YBCO single domain with levitation force of 10-13 kg/cm{sup 2} using TSMG processing technique.

  3. Correlação linear e espacial entre produtividade de Brachiaria brizantha, densidade do solo e porosidade total em função do sistema de manejo do solo Linear and spatial correlations among forage yield, bulk density and total porosity in function of soil management system

    Directory of Open Access Journals (Sweden)

    Edney L. da Vitória

    2012-10-01

    Full Text Available A densidade e a porosidade são propriedades físicas do solo que são alteradas em função do sistema de manejo utilizado, com consequente influência sobre a produtividade das culturas. A produtividade da planta forrageira, Brachiaria brizantha, em função da densidade do solo e da porosidade total foi analisada em dois sistemas de manejo de solo, em experimento conduzido no segundo semestre de 2009, no município de Santa Teresa, no Estado do Espírito Santo. O objetivo foi estudar a variabilidade e as correlações lineares e espaciais entre os atributos da planta e do solo, visando a selecionar um indicador da qualidade física do solo de boa representatividade para produtividade de forragem. Marcaram-se duas parcelas de 40 m por 50 m a cada 5 m, em duas direções, resultando em um reticulado retangular de 99 pontos, em cada um dos sistemas utilizados: preparo convencional e plantio direto. Os atributos estudados, além de não terem variado aleatoriamente, apresentaram variabilidade dos dados entre média e alta, e seguiram padrões espaciais bem definidos, com alcance entre 20,3 e 24,2 m. Por sua vez, a correlação linear entre o atributo da planta e os do solo, em função do elevado número de observações, foi baixa. A melhor correlação para produtividade de matéria seca foi com a densidade do solo na profundidade de 0,0 - 0,15 m, independentemente do sistema de manejo do solo, indicando que a produtividade e a densidade do solo são inversamente proporcionais. Portanto, a densidade do solo avaliada na camada de 0,0 - 0,15 m apresentou-se como satisfatório indicador da qualidade física do solo, quando se considerou a produtividade da forrageira.Total porosity and bulk density are strongly affected by soil management, which reflects directly in agricultural productivity. The productivity of the forage, Brachiaria brizantha, in function of bulk density and total porosity was analyzed in two soil management systems, in an

  4. Gravitational potential wells and the cosmic bulk flow

    CERN Document Server

    Kumar, Abhinav; Feldman, Hume A; Watkins, Richard

    2015-01-01

    The bulk flow is a volume average of the peculiar velocities and a useful probe of the mass distribution on large scales. The gravitational instability model views the bulk flow as a potential flow that obeys a Maxwellian Distribution. We use two N-body simulations, the LasDamas Carmen and the Horizon Run, to calculate the bulk flows of various sized volumes in the simulation boxes. Once we have the bulk flow velocities as a function of scale, we investigate the mass and gravitational potential distribution around the volume. We found that matter densities can be asymmetrical and difficult to detect in real surveys, however, the gravitational potential and its gradient may provide better tools to investigate the underlying matter distribution. This study shows that bulk flows are indeed potential flows and thus provides information on the flow sources. We also show that bulk flow magnitudes follow a Maxwellian distribution on scales $>10\\ h^{-1}$Mpc.

  5. Gravitational potential wells and the cosmic bulk flow

    Science.gov (United States)

    Wang, Yuyu; Kumar, Abhinav; Feldman, Hume; Watkins, Richard

    2016-03-01

    The bulk flow is a volume average of the peculiar velocities and a useful probe of the mass distribution on large scales. The gravitational instability model views the bulk flow as a potential flow that obeys a Maxwellian Distribution. We use two N-body simulations, the LasDamas Carmen and the Horizon Run, to calculate the bulk flows of various sized volumes in the simulation boxes. Once we have the bulk flow velocities as a function of scale, we investigate the mass and gravitational potential distribution around the volume. We found that matter densities can be asymmetrical and difficult to detect in real surveys, however, the gravitational potential and its gradient may provide better tools to investigate the underlying matter distribution. This study shows that bulk flows are indeed potential flows and thus provides information on the flow sources. We also show that bulk flow magnitudes follow a Maxwellian distribution on scales > 10h-1 Mpc.

  6. Wormholes in Bulk Viscous Cosmology

    OpenAIRE

    Jamil, Mubasher

    2008-01-01

    We investigate the effects of the accretion of phantom energy with non-zero bulk viscosity onto a Morris-Thorne wormhole. We have found that if the bulk viscosity is large then the mass of wormhole increases rapidly as compared to small or zero bulk viscosity.

  7. Reluctance motors with bulk HTS material

    International Nuclear Information System (INIS)

    In recent years we have successfully designed, built and tested several reluctance motors with YBCO bulk material incorporated into the rotor, working at 77 K. Our last motor type SRE150 was tested up to 200 kW. The aim of our investigations is the construction of motors with extremely high power density and dynamics. In comparison to conventional motor types the advantage of HTS reluctance motors with respect to size and dynamics could be demonstrated. Some fields of possible future applications will be described. These motors show a significant improvement in performance using high quality HTS bulk elements in the rotor. Until now the motor parameters have been limited by the current density which could be obtained in the bulk material at 77 K and by the geometric dimensions of the segments available. Therefore we expect further improvements in the case of these materials. Since the total motor including stator and rotor is working at low temperature we have to optimize the windings and the magnetic circuit to these operation conditions. A new design of a 200 kW motor in order to achieve increased power density and the theoretical results of our calculations will be shown

  8. Creating bulk nanocrystalline metal.

    Energy Technology Data Exchange (ETDEWEB)

    Fredenburg, D. Anthony (Georgia Institute of Technology, Atlanta, GA); Saldana, Christopher J. (Purdue University, West Lafayette, IN); Gill, David D.; Hall, Aaron Christopher; Roemer, Timothy John (Ktech Corporation, Albuquerque, NM); Vogler, Tracy John; Yang, Pin

    2008-10-01

    Nanocrystalline and nanostructured materials offer unique microstructure-dependent properties that are superior to coarse-grained materials. These materials have been shown to have very high hardness, strength, and wear resistance. However, most current methods of producing nanostructured materials in weapons-relevant materials create powdered metal that must be consolidated into bulk form to be useful. Conventional consolidation methods are not appropriate due to the need to maintain the nanocrystalline structure. This research investigated new ways of creating nanocrystalline material, new methods of consolidating nanocrystalline material, and an analysis of these different methods of creation and consolidation to evaluate their applicability to mesoscale weapons applications where part features are often under 100 {micro}m wide and the material's microstructure must be very small to give homogeneous properties across the feature.

  9. Diffusion or bulk flow

    DEFF Research Database (Denmark)

    Schulz, Alexander

    2015-01-01

    the concentration gradient or bulk flow along a pressure gradient. The driving force seems to depend on the mode of phloem loading. In a majority of plant species phloem loading is a thermodynamically active process, involving the activity of membrane transporters in the sieve-element companion cell complex. Since...... assimilate movement includes an apoplasmic step, this mode is called apoplasmic loading. Well established is also the polymer-trap loading mode, where the phloem-transport sugars are raffinose-family oligomers in herbaceous plants. Also this mode depends on the investment of energy, here for sugar......Assimilates synthesized in the mesophyll of mature leaves move along the pre-phloem transport pathway to the bundle sheath of the minor veins from which they are loaded into the phloem. The present review discusses the most probable driving force(s) for the pre-phloem pathway, diffusion down...

  10. Bulk-Fill Resin Composites

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Havndrup-Pedersen, Cæcilie; Honoré, Daniel;

    2015-01-01

    the restorative procedure. The aim of this study, therefore, was to compare the depth of cure, polymerization contraction, and gap formation in bulk-fill resin composites with those of a conventional resin composite. To achieve this, the depth of cure was assessed in accordance with the International Organization...... for Standardization 4049 standard, and the polymerization contraction was determined using the bonded-disc method. The gap formation was measured at the dentin margin of Class II cavities. Five bulk-fill resin composites were investigated: two high-viscosity (Tetric EvoCeram Bulk Fill, SonicFill) and three low......-viscosity (x-tra base, Venus Bulk Fill, SDR) materials. Compared with the conventional resin composite, the high-viscosity bulk-fill materials exhibited only a small increase (but significant for Tetric EvoCeram Bulk Fill) in depth of cure and polymerization contraction, whereas the low-viscosity bulk...

  11. Renormalization group approach to causal bulk viscous cosmological models

    International Nuclear Information System (INIS)

    The renormalization group method is applied to the study of homogeneous and flat Friedmann-Robertson-Walker type universes, filled with a causal bulk viscous cosmological fluid. The starting point of the study is the consideration of the scaling properties of the gravitational field equations, the causal evolution equation of the bulk viscous pressure and the equations of state. The requirement of scale invariance imposes strong constraints on the temporal evolution of the bulk viscosity coefficient, temperature and relaxation time, thus leading to the possibility of obtaining the bulk viscosity coefficient-energy density dependence. For a cosmological model with bulk viscosity coefficient proportional to the Hubble parameter, we perform the analysis of the renormalization group flow around the scale-invariant fixed point, thereby obtaining the long-time behaviour of the scale factor

  12. Theoretical evaluation of bulk viscosity: Expression for relaxation time

    Science.gov (United States)

    Hossein Mohammad Zaheri, Ali; Srivastava, Sunita; Tankeshwar, K.

    2007-10-01

    A theoretical calculation of bulk viscosity has been carried out by deriving an expression for the relaxation time which appears in the formula for bulk viscosity derived by Okumura and Yonezawa. The expression involved a pair distribution function and interaction potential. Numerical results have been obtained over a wide range of densities and temperatures for Lennard-Jones fluids. It is found that our results provide a good description of bulk viscosity as has been judged by comparing the results with nonequilibrium molecular dynamics results. In addition, our results demonstrate the importance of the multiparticle correlation function.

  13. Waveform control pulse magnetization for HTS bulk magnet

    Science.gov (United States)

    Ida, Tetsuya; Shigeuchi, Koji; Okuda, Sayo; Watasaki, Masahiro; Izumi, Mitsuru

    2016-03-01

    For the past 10 years, we have studied high-temperature superconducting (HTS) bulk magnets for use in electromagnetic rotating machines. If the magnetic field effectively magnetizes the HTS bulk, then the size of the motor and generator can be reduced without a reduction in output. We showed that the melt-textured Gd-Ba-Cu-O HTS bulk effectively traps a high magnetic field using waveform control pulse magnetization (WCPM). WCPM makes it possible to generate any pulsed magnetic field waveform by appropriately changing the duty ratio of the pulse width modulation. By chopping so that the pulsed magnetic field has a period of about 1ms, the WCPM technology enables active control of the rise time and suppresses magnetic flux motion that decreases magnetization efficiency. This method is also useful for any HTS bulk magnet, and the high magnetic flux density is trapped in the HTS bulk by a single pulse magnetic field. We developed a magnetizer that has a feedback system from the penetrated magnetic flux density to realize WCPM. In this research, using only a single pulse magnetic field of WCPM method at 77K, an HTS bulk with a 45mm diameter and 19mm thickness trapped a maximum magnetic field of 1.63T, which is more than 90% of the trapped magnetic flux density by FC magnetization. This result suggests that the pulse magnetizing method can replace the conventional field-cooled method and promote the practical use of HTS magnets for electromagnetic power applications.

  14. Magnetic levitation force between a superconducting bulk magnet and a permanent magnet

    OpenAIRE

    J. J. Wang; C. Y. He; Meng, L F; C Li; Han, R. S.; Gao, Z X

    2002-01-01

    The current density in a disk-shaped superconducting bulk magnet and the magnetic levitation force exerted on the superconducting bulk magnet by a cylindrical permanent magnet are calculated from first principles. The effect of the superconducting parameters of the superconducting bulk is taken into account by assuming the voltage-current law and the material law. The magnetic levitation force is dominated by the remnant current density, which is induced by switching off the applied magnetizi...

  15. Calculated Bulk Properties of the Actinide Metals

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt; Andersen, O. K.; Johansson, B.

    1978-01-01

    Self-consistent relativistic calculations of the electronic properties for seven actinides (Ac-Am) have been performed using the linear muffin-tin orbitals method within the atomic-sphere approximation. Exchange and correlation were included in the local spin-density scheme. The theory explains t...... the variation of the atomic volume and the bulk modulus through the 5f series in terms of an increasing 5f binding up to plutonium followed by a sudden localisation (through complete spin polarisation) in americium...

  16. Mining the bulk positron lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Aourag, H.; Guittom, A. [Centre de Recherche Nucleaire d' Alger (CRNA), Alger Gare - Algiers (Algeria)

    2009-02-15

    We introduce a new approach to investigate the bulk positron lifetimes of new systems based on data-mining techniques. Through data mining of bulk positron lifetimes, we demonstrate the ability to predict the positron lifetimes of new semiconductors on the basis of available semiconductor data already studied. Informatics techniques have been applied to bulk positron lifetimes for different tetrahedrally bounded semiconductors in order to discover computational design rules. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Mining the bulk positron lifetime

    International Nuclear Information System (INIS)

    We introduce a new approach to investigate the bulk positron lifetimes of new systems based on data-mining techniques. Through data mining of bulk positron lifetimes, we demonstrate the ability to predict the positron lifetimes of new semiconductors on the basis of available semiconductor data already studied. Informatics techniques have been applied to bulk positron lifetimes for different tetrahedrally bounded semiconductors in order to discover computational design rules. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Advances in bulk port development

    Energy Technology Data Exchange (ETDEWEB)

    Soros, P. (Soros Associates Consulting Engineers, New York, NY (USA))

    1991-03-01

    The article features several recently developed bulk ports which illustrate aspects of new technology or concepts in maritime transport. Low handling capacity bulk terminals at Ponta da Madeira, Brazil and Kooragang Island, Australia and the low-cost bulk port at Port of Corpus Christi, Texas are described. Operations at the ports of Pecket and Tocopilla in Chile, which had special technical problems, are mentioned. Coal terminals at Port Kembla, Australia and St. Johns River in Florid Jacksonville, Florida are featured as examples of terminals which had to be designed to meet high environmental standards. 13 refs., 2 figs., 14 photos.

  19. Bulk viscous cosmology in early Universe

    Indian Academy of Sciences (India)

    C P Singh

    2008-07-01

    The effect of bulk viscosity on the early evolution of Universe for a spatially homogeneous and isotropic Robertson-Walker model is considered. Einstein's field equations are solved by using `gamma-law' equation of state = ( - 1)ρ, where the adiabatic parameter gamma () depends on the scale factor of the model. The `gamma' function is defined in such a way that it describes a unified solution of early evolution of the Universe for inflationary and radiation-dominated phases. The fluid has only bulk viscous term and the coefficient of bulk viscosity is taken to be proportional to some power function of the energy density. The complete general solutions have been given through three cases. For flat space, power-law as well as exponential solutions are found. The problem of how the introduction of viscosity affects the appearance of singularity, is briefly discussed in particular solutions. The deceleration parameter has a freedom to vary with the scale factor of the model, which describes the accelerating expansion of the Universe.

  20. Correlação linear e espacial entre a produtividade de forragem, a porosidade total e a densidade do solo de Pereira Barreto (SP Linear and spatial correlations between forage yield, total porosity and bulk density in Pereira Barreto, Brazil

    Directory of Open Access Journals (Sweden)

    Cesar Gustavo da Rocha Lima

    2007-12-01

    Full Text Available Em relação aos sistemas de manejo adotados pelo homem, a porosidade total e a densidade do solo são atributos ativamente alterados, refletindo decisivamente sobre a produtividade vegetal agrícola. No ano agrícola de 2005, na Fazenda Bonança, no município de Pereira Barreto, Estado de São Paulo, Brasil, foram analisadas a produtividade de forragem do milho outonal (MSF no sistema plantio direto irrigado, a porosidade total (PT e a densidade do solo (DS em profundidade, em um Latossolo Vermelho distrófico. O objetivo foi estudar a variabilidade e as correlações lineares e espaciais entre os atributos da planta e do solo, visando selecionar um indicador da qualidade física do solo de boa representatividade para produtividade da forragem. Foi instalada a malha geoestatística, para coleta de dados do solo e planta, contendo 125 pontos amostrais, numa área de 2.500 m². Os atributos estudados, além de não terem variado aleatoriamente, apresentaram variabilidade dos dados entre média e baixa e seguiram padrões espaciais bem definidos, com alcance entre 6,8 e 23,7 m. Por sua vez, a correlação linear entre o atributo da planta e os do solo, em razão do elevado número de observações, foi baixa. As observações de melhor correlação com a MSF foram a DS1 e a PT1. Entretanto, do ponto de vista espacial, houve excelente correlação inversa entre a MSF e a DS1, assim como entre a DS1 e a PT1. Nos sítios onde a DS1 aumentou (1,45-1,64 kg dm-3 a MSF variou entre 11.653 e 14.552 kg ha-1; já naqueles onde diminuiu (1,35-1,45 kg dm-3 a MSF, ficou entre 14.552 e 17.450 kg ha-1. Portanto, a densidade global, avaliada na camada de 0-0,10 m (DS1, apresentou-se como satisfatório indicador da qualidade física do solo de Pereira Barreto (SP, quando destinado à produtividade de forragem do milho outonal.Total porosity and bulk density are strongly affected by soil management, which is reflects directly in agricultural productivity. In 2005

  1. 载气对炭/炭复合材料沉积速率、体密度和微观结构的影响%Effect of carrier gases on densification rate, bulk density and microstructure of carbon/carbon composites

    Institute of Scientific and Technical Information of China (English)

    侯振华; 郝名扬; 罗瑞盈; 向巧; 杨威; 商海东; 许怀哲

    2015-01-01

    分别采用H2和CO2作为载气,CH4为前躯体,通过等温化学气相渗积制备炭/炭复合材料,通过偏光显微镜、拉曼光谱、X射线衍射和透射电镜对材料微观结构表征以及渗积过程密度变化,研究载气对沉积速率、体密度和微观结构的影响规律。结果表明:在渗积前50 h,CH4-H2体系的沉积速率明显大于CH4-CO2体系,但在其余渗积时间里,CH4-H2体系的沉积速率小于CH4-CO2体系。当载气从H2变成CO2时,复合材料的体密度从1.626 g/cm3增加到1.723 g/cm3,最大径向密度梯度从0.074 g/cm3减小到0.056 g/cm3。同时,基体炭从纯的粗糙体炭转变为杂化粗糙体炭含有过度生长锥,且平均石墨化度从62.7%下降到50.8%。这些显著的变化是由于CO2的氧化作用降低了表面沉积速率,却没有降低孔内沉积速率,同时大量的缺陷形成于层状石墨烯结构中导致形成过度生长锥,降低了热解炭织构。%Effect of carrier gases( H2 and CO2 ) on the densification rate, bulk density and microstructure of carbon/carbon com-posites fabricated by isothermalchemical vapor infiltration from methane ( CH4 ) was investigated. In the initial 50 h, the densifica-tion rate obtained from CH4-H2 is obviously higher than that from CH4-CO2 , while the densification rate from CH4-H2 is lower than that from CH4-CO2 with a further increase of infiltration time. When the carrier gas is switched from H2 to CO2 , the average bulk density of the compositeincreases from 1. 626 to 1. 723 g/cm3 , the maximum radial density gradient decreases from 0. 074 to 0. 056 g/cm3 , the matrix changes from the pure rough laminar to hybrid rough laminar pyrocarbon with overgrowth cones, and the average degree of graphitization reduces from 62. 7% to 50. 8%. These significant changes are caused by the fact that CO2 can ef-fectively reduce the surface deposition rate but does not inhibit the in-pore infiltration, and thatdefects are formed in the deposits by a

  2. Bulk solitary waves in elastic solids

    Science.gov (United States)

    Samsonov, A. M.; Dreiden, G. V.; Semenova, I. V.; Shvartz, A. G.

    2015-10-01

    A short and object oriented conspectus of bulk solitary wave theory, numerical simulations and real experiments in condensed matter is given. Upon a brief description of the soliton history and development we focus on bulk solitary waves of strain, also known as waves of density and, sometimes, as elastic and/or acoustic solitons. We consider the problem of nonlinear bulk wave generation and detection in basic structural elements, rods, plates and shells, that are exhaustively studied and widely used in physics and engineering. However, it is mostly valid for linear elasticity, whereas dynamic nonlinear theory of these elements is still far from being completed. In order to show how the nonlinear waves can be used in various applications, we studied the solitary elastic wave propagation along lengthy wave guides, and remarkably small attenuation of elastic solitons was proven in physical experiments. Both theory and generation for strain soliton in a shell, however, remained unsolved problems until recently, and we consider in more details the nonlinear bulk wave propagation in a shell. We studied an axially symmetric deformation of an infinite nonlinearly elastic cylindrical shell without torsion. The problem for bulk longitudinal waves is shown to be reducible to the one equation, if a relation between transversal displacement and the longitudinal strain is found. It is found that both the 1+1D and even the 1+2D problems for long travelling waves in nonlinear solids can be reduced to the Weierstrass equation for elliptic functions, which provide the solitary wave solutions as appropriate limits. We show that the accuracy in the boundary conditions on free lateral surfaces is of crucial importance for solution, derive the only equation for longitudinal nonlinear strain wave and show, that the equation has, amongst others, a bidirectional solitary wave solution, which lead us to successful physical experiments. We observed first the compression solitary wave in the

  3. Densidade e qualidade dos estratos de forragem do capim Tanzânia (Panicum maximum Jacq. Cv. Tanzânia-1 manejado em diferentes alturas, sob pastejo Density bulk and quality of Tanzania grass layers (Panicum maximum Jacq.cv. Tanzania-1, at different heights in grazing

    Directory of Open Access Journals (Sweden)

    Geraldo Tadeu dos Santos

    2001-05-01

    Full Text Available O objetivo do trabalho foi avaliar o efeito de diferentes alturas (24; 26; 43; 45; 52; 62; 73 e 78 cm do pasto sobre a qualidade de forragem e estrutura do perfil do capim-Tanzânia, (Panicum maximum Jacq. cv. Tanzânia – 1 (Poaceae. Foram utilizados novilhos da raça Nelore sob pastejo com carga animal variável, por meio da técnica put and take. O delineamento experimental utilizado foi inteiramente casualizado, com duas repetições. A densidade de matéria seca total (DMT aumentou com o avanço no período experimental, enquanto a densidade de matéria seca de lâminas (DML não foi influenciada pelo período e pela altura do pasto. O estrato superior da pastagem foi a porção de maior qualidade, apresentando maior DML e maior teor de PB. Os estratos inferiores apresentaram menor qualidade, devido à maior DMT e menor DML, acarretando em maiores valores de FDA e FDN e menores teores de PB. O conteúdo de minerais das lâminas foi superior aos colmos, mantendo-se inalterado com relação aos estratos da pastagem.The effect of different sward heights (24; 26; 43; 45; 52; 62; 73 and 78 cm on forage quality and profile structure Tanzania grass, Panicum maximum Jacq. cv. Tanzania – 1 (Poaceae is provided. Nelore steers were used in grazing at variable stocking rates with put and take technique. The experimental design was completely randomized, with two replications. Total dry matter bulk densitity (TDMD increased during experimental period, while the leaf blade dry matter bulk density (LDMD was not influenced by period on by sward height. The upper layers had the best quality with higher LDMD and CP levels. Lower layers had the worst quality, due the higher TDMD and lower LDMD. This fact caused higher ADF and NDF levels and lower CP levels. Leaf blade mineral content was higher than that of stem, and remained unaltered in relation to the different layers.

  4. Bulk and shear viscosities of hot and dense hadron gas

    CERN Document Server

    Kadam, Guru Prakash

    2014-01-01

    We estimate bulk and shear viscosity at finite temperature and baryon densities of hadronic matter within hadron resonance gas model. For bulk viscosity we use low energy theorems of QCD for the energy momentum tensor correlators. For shear viscosity coefficient, we estimate the same using molecular kinetic theory to relate the shear viscosity coefficient to average momentum of the hadrons in the hot and dense hadron gas. The bulk viscosity to entropy ratio increases with chemical potential and is related to the reduction of velocity of sound at nonzero chemical potential. The shear viscosity to entropy ratio on the other hand, shows a nontrivial behavior with the ratio decreasing with chemical potential for small temperatures but increasing with chemical potential at high temperatures and is related to decrease of entropy density with chemical potential at high temperature due to finite volume of the hadrons.

  5. Collapse of Incoherent Light Beams in Inertial Bulk Kerr Media

    DEFF Research Database (Denmark)

    Bang, Ole; Edmundson, Darran; Królikowski, Wieslaw

    1999-01-01

    We use the coherent density function theory to show that partially coherent beams are unstable and may collapse in inertial bulk Kerr media. The threshold power for collapse, and its dependence on the degree of coherence, is found analytically and checked-numerically. The internal dynamics of the...

  6. Looking for a bulk point

    CERN Document Server

    Maldacena, Juan; Zhiboedov, Alexander

    2015-01-01

    We consider Lorentzian correlators of local operators. In perturbation theory, singularities occur when we can draw a position-space Landau diagram with null lines. In theories with gravity duals, we can also draw Landau diagrams in the bulk. We argue that certain singularities can arise only from bulk diagrams, not from boundary diagrams. As has been previously observed, these singularities are a clear diagnostic of bulk locality. We analyze some properties of these perturbative singularities and discuss their relation to the OPE and the dimensions of double-trace operators. In the exact nonperturbative theory, we expect no singularity at these locations. We prove this statement in 1+1 dimensions by CFT methods.

  7. Bulk Viscosity of Interacting Hadrons

    OpenAIRE

    Wiranata, A.; M. Prakash

    2009-01-01

    We show that first approximations to the bulk viscosity $\\eta_v$ are expressible in terms of factors that depend on the sound speed $v_s$, the enthalpy, and the interaction (elastic and inelastic) cross section. The explicit dependence of $\\eta_v$ on the factor $(\\frac 13 - v_s^2)$ is demonstrated in the Chapman-Enskog approximation as well as the variational and relaxation time approaches. The interesting feature of bulk viscosity is that the dominant contributions at a given temperature ari...

  8. Bulk Viscosity of Interacting Hadrons

    CERN Document Server

    Wiranata, A

    2009-01-01

    We show that first approximations to the bulk viscosity $\\eta_v$ are expressible in terms of factors that depend on the sound speed $v_s$, the enthalpy, and the interaction (elastic and inelastic) cross section. The explicit dependence of $\\eta_v$ on the factor $(\\frac 13 - v_s^2)$ is demonstrated in the Chapman-Enskog approximation as well as the variational and relaxation time approaches. The interesting feature of bulk viscosity is that the dominant contributions at a given temperature arise from particles which are neither extremely nonrelativistic nor extremely relativistic. Numerical results for a model binary mixture are reported.

  9. Bulk viscosity and deflationary universes

    CERN Document Server

    Lima, J A S; Waga, I

    2007-01-01

    We analyze the conditions that make possible the description of entropy generation in the new inflationary model by means of a nearequilibrium process. We show that there are situations in which the bulk viscosity cannot describe particle production during the coherent field oscillations phase.

  10. Longitudinal bulk acoustic mass sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Teva, Jordi; Boisen, Anja;

    2009-01-01

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10(-15) g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise i...

  11. A route to transparent bulk metals

    KAUST Repository

    Schwingenschlögl, Udo

    2012-07-23

    Hypothetical compounds based on a sapphire host are investigated with respect to their structural as well as electronic features. The results are obtained by electronic structure calculations within density functional theory and the generalized gradient approximation. A quarter of the Al atoms in Al 2O 3 is replaced by a 4d transition metal M ion, with d 0 to d 9 electronic configuration. We perform structure optimizations for all the compounds and analyze the electronic states. Due to the sizeable band gap of the Al 2O 3 host, we can identify promising candidates for transparent bulk metals. We explain the mechanisms leading to this combination of materials properties. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Bianchi Type Ⅲ String Cosmological Model with Bulk Viscosity

    Institute of Scientific and Technical Information of China (English)

    WANGXing-Xiang

    2004-01-01

    The Bianchi type Ⅲ cosmological model for a cloud string with bulk viscosity are presented. To obtain a determinate model, an equation of state ρ=kλ and a relation between metric potentials B = Cn are assumed. The physical and geometric aspects of the model are also discussed. The model describes a shearing non-rotating continuously expanding universe with a big-bang start, and the relation between the coefficient of bulk viscosity and the energy density is ζ∝ρ1/2.

  13. Enhancement of the Bulk Photovoltaic Effect in Topological Insulators

    Science.gov (United States)

    Tan, Liang Z.; Rappe, Andrew M.

    2016-06-01

    We investigate the shift current bulk photovoltaic response of materials close to a band inversion topological phase transition. We find that the bulk photocurrent reverses direction across the band inversion transition, and that its magnitude is enhanced in the vicinity of the phase transition. These results are demonstrated with first principles density functional theory calculations of BiTeI and CsPbI3 under hydrostatic pressure, and explained with an analytical model, suggesting that this phenomenon remains robust across disparate material systems.

  14. Reversible ultrafast melting in bulk CdSe

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wenzhi [School of Electronic Engineering, Heilongjiang University, Harbin 150080 (China); Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); He, Feng; Wang, Yaguo, E-mail: yaguo.wang@austin.utexas.edu [Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); The Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2016-02-07

    In this work, transient reflectivity changes in bulk CdSe have been measured with two-color femtosecond pump-probe spectroscopy under a wide range of pump fluences. Three regions of reflectivity change with pump fluences have been consistently revealed for excited carrier density, coherent phonon amplitude, and lattice temperature. For laser fluences from 13 to 19.3 mJ/cm{sup 2}, ultrafast melting happens in first several picoseconds. This melting process is purely thermal and reversible. A complete phase transformation in bulk CdSe may be reached when the absorbed laser energy is localized long enough, as observed in nanocrystalline CdSe.

  15. Enhancement of the Bulk Photovoltaic Effect in Topological Insulators.

    Science.gov (United States)

    Tan, Liang Z; Rappe, Andrew M

    2016-06-10

    We investigate the shift current bulk photovoltaic response of materials close to a band inversion topological phase transition. We find that the bulk photocurrent reverses direction across the band inversion transition, and that its magnitude is enhanced in the vicinity of the phase transition. These results are demonstrated with first principles density functional theory calculations of BiTeI and CsPbI_{3} under hydrostatic pressure, and explained with an analytical model, suggesting that this phenomenon remains robust across disparate material systems.

  16. Optimization of PGNAA instrument design for bulk coal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, C.; Salgado, J.; Carvalho, F.G. (National Laboratory for Industrial Technology and Engineering, Sacavem (Portugal). Physics Dept.)

    1993-06-01

    A simulation study of a PGNAA system for bulk coal analysis has been carried out using the MCNP code to investigate the dependence of the system's performance on design parameters for different coal compositions and bulk densities. Calculations were performed for simulated arrangements using a naked point [sup 252]Cf source and the source surrounded by a sphere of moderating material. Results for different sample sizes and different radii of the moderating sphere are reported. The system's optimization based upon the proper choice of sample size and amount of external thermalization is discussed. 3 refs., 18 figs., 1 tab.

  17. Gap-related trapped magnetic flux dependence between single and combined bulk superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Z., E-mail: zgdeng@gmail.co [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, Tokyo 135-8533 (Japan); Miki, M.; Felder, B.; Tsuzuki, K.; Shinohara, N.; Uetake, T.; Izumi, M. [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, Tokyo 135-8533 (Japan)

    2011-05-15

    Highlights: {yields} Rectangular YBCO bulks to realize a compact combination. {yields} The gap effect was added to consider in the trapped flux density mapping. {yields} The trapped-flux dependence between single and combined bulks is gap related. {yields} It is possible to estimate the total magnetic flux of bulk combinations. - Abstract: Aiming at examining the trapped-flux dependence between single and combined bulk superconductors for field-pole applications, three rectangular Y{sub 1.65}Ba{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) bulks with a possibly compact combination were employed to investigate the trapped-flux characteristics of single and combined bulks with a field-cooling magnetization (FCM) method. A gap-related dependence was found between them. At lower gaps of 1 mm and 5 mm, the peak trapped fields and total magnetic flux of combined bulks are both smaller than the additive values of each single bulk, which can be ascribed to the demagnetization influences of the field around the bulk generated by the adjacent ones. While, at larger gaps like 10 mm, the situation becomes reversed. The combined bulks can attain bigger peak trapped fields as well as total magnetic flux, which indicates that the magnetic field by the bulk combination can reach higher gaps, thanks to the bigger magnetic energy compared with the single bulk. The presented results show that, on one hand, it is possible to estimate the total trapped magnetic flux of combined bulks by an approximate additive method of each single bulk while considering a demagnetization factor; on the other hand, it also means that the performance of combined bulks will be superior to the addition of each single bulk at larger gaps, thus preferable for large-scaled magnet applications.

  18. Tensão e extração de água em mesa de tensão e coluna de areia, em dois solos com elevada densidade Water tension and extraction by suction table and sand suction column in two soils with high bulk density

    Directory of Open Access Journals (Sweden)

    Paulo Ivonir Gubiani

    2009-11-01

    Full Text Available A determinação da umidade do solo submetido a uma dada tensão segue o pressuposto que o potencial mátrico da água do solo esteja em equilíbrio com a tensão aplicada. A verificação do tempo para a tensão da água do solo atingir o equilíbrio com a tensão de 6kPa foi efetuada em um Argissolo Vermelho Distrófico típico e um Latossolo Vermelho Distrófico típico. No Argissolo, o equilíbrio entre a tensão aplicada e o potencial mátrico da água do solo, para a maioria das amostras, foi verificado entre 72 e 96h, enquanto no Latossolo não houve equilíbrio no período de 168h. A tensão nas amostras não teve correlação significativa com a densidade do solo e não atingiu a tensão aplicada na mesa de tensão e na coluna de areia. No entanto, mais de 97% da água passível de ser removida dos dois solos foi extraída até 48h, o que sugere que esse tempo é suficiente para a estimativa da umidade na tensão de 6kPa, independentemente do teor de argila do solo.The determination of moisture content in soils under tension follows the assumption that the water matric potential is at equilibrium with an applied tension. The time the soil water tension reaches the equilibrium under the 6kPa tension was determined in Hapludalf and Hapludox clay soils. In the Hapludalf, the equilibrium between the applied tension and water matric potential, in most of the samples, was obtained between 72 and 96h, while in Hapludox, equilibrium was not reached until the 168h. The water tension in the samples had no significant correlation with bulk density and did not reach the tension applied on the suction table and sand suction column. Nevertheless, more than 97% of the soil water was extracted at 48h both in Hapludalf and Hapludox, suggesting that this time is sufficient to estimate the soil moisture at 6kPa tension, independently of clay content.

  19. Coulombic Fluids Bulk and Interfaces

    CERN Document Server

    Freyland, Werner

    2011-01-01

    Ionic liquids have attracted considerable interest in recent years. In this book the bulk and interfacial physico-chemical characteristics of various fluid systems dominated by Coulomb interactions are treated which includes molten salts, ionic liquids as well as metal-molten salt mixtures and expanded fluid metals. Of particular interest is the comparison of the different systems. Topics in the bulk phase concern the microscopic structure, the phase behaviour and critical phenomena, and the metal-nonmetal transition. Interfacial phenomena include wetting transitions, electrowetting, surface freezing, and the electrified ionic liquid/ electrode interface. With regard to the latter 2D and 3D electrochemical phase formation of metals and semi-conductors on the nanometer scale is described for a number of selected examples. The basic concepts and various experimental methods are introduced making the book suitable for both graduate students and researchers interested in Coulombic fluids.

  20. Bulk Locality from Entanglement in Gauge/Gravity Duality

    CERN Document Server

    Lin, Jennifer

    2015-01-01

    Gauge/gravity duality posits an equivalence between certain strongly coupled quantum field theories and theories of gravity with negative cosmological constant in a higher number of spacetime dimensions. The map between the degrees of freedom on the two sides is non-local and incompletely understood. I describe recent work towards characterizing this map using entanglement in the QFT, where near the dual AdS boundary, the classical energy density at a point in the bulk is stored in the relative entropies of boundary subregions whose homologous minimal surfaces pass through the bulk point. I also derive bulk classical energy conditions near the AdS boundary from entanglement inequalities in the CFT. This is based on the paper [1] with Matilde Marcolli, Hirosi Ooguri and Bogdan Stoica. More generally, in recent years, there has appeared some evidence that quantum entanglement is responsible for the emergence of spacetime. I review and comment on the state of these developments.

  1. Road density

    Data.gov (United States)

    U.S. Environmental Protection Agency — Road density is generally highly correlated with amount of developed land cover. High road densities usually indicate high levels of ecological disturbance. More...

  2. Large-scale HTS bulks for magnetic application

    Science.gov (United States)

    Werfel, Frank N.; Floegel-Delor, Uta; Riedel, Thomas; Goebel, Bernd; Rothfeld, Rolf; Schirrmeister, Peter; Wippich, Dieter

    2013-01-01

    ATZ Company has constructed about 130 HTS magnet systems using high-Tc bulk magnets. A key feature in scaling-up is the fabrication of YBCO melts textured multi-seeded large bulks with three to eight seeds. Except of levitation, magnetization, trapped field and hysteresis, we review system engineering parameters of HTS magnetic linear and rotational bearings like compactness, cryogenics, power density, efficiency and robust construction. We examine mobile compact YBCO bulk magnet platforms cooled with LN2 and Stirling cryo-cooler for demonstrator use. Compact cryostats for Maglev train operation contain 24 pieces of 3-seed bulks and can levitate 2500-3000 N at 10 mm above a permanent magnet (PM) track. The effective magnetic distance of the thermally insulated bulks is 2 mm only; the stored 2.5 l LN2 allows more than 24 h operation without refilling. 34 HTS Maglev vacuum cryostats are manufactured tested and operate in Germany, China and Brazil. The magnetic levitation load to weight ratio is more than 15, and by group assembling the HTS cryostats under vehicles up to 5 t total loads levitated above a magnetic track is achieved.

  3. 46 CFR 151.03-21 - Filling density.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Filling density. 151.03-21 Section 151.03-21 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Definitions § 151.03-21 Filling density. The ratio, expressed...

  4. Ab-initio investigations of the electronic properties of bulk wurtzite Beryllia and its derived nanofilms

    KAUST Repository

    Goumri-Said, Souraya

    2010-08-01

    In this Letter we investigate the electronic properties of the bulk and the nanofilm BeO in wurtzite structure. We performed a first-principles pseudo-potential method within the generalized gradient approximation. We will give more importance to the changes in band structure and density of states between the bulk structure and its derived nanofilms. The bonding characterization will be investigated via the analysis Mulliken population and charge density contours. It is found that the nanofilm retains the same properties as its bulk structure with slight changes in electronic properties and band structure which may offer some unusual transport properties. © 2010 Elsevier B.V. All rights reserved.

  5. Iron - based bulk amorphous alloys

    Directory of Open Access Journals (Sweden)

    R. Babilas

    2010-07-01

    Full Text Available Purpose: The paper presents a structure characterization, thermal and soft magnetic properties analysis of Fe-based bulk amorphous materials in as-cast state and after crystallization process. In addition, the paper gives some brief review about achieving, formation and structure of bulk metallic glasses as a special group of amorphous materials.Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4 metallic glass in form of ribbons and rods. The amorphous structure of tested samples was examined by X-ray diffraction (XRD, transmission electron microscopy (TEM and scanning electron microscopy (SEM methods. The thermal properties of the glassy samples were measured using differential thermal analysis (DTA and differential scanning calorimetry (DSC. The magnetic properties contained initial and maximum magnetic permeability, coercive force and magnetic after-effects measurements were determined by the Maxwell-Wien bridge and VSM methods.Findings: The X-ray diffraction and transmission electron microscopy investigations revealed that the studied as-cast bulk metallic glasses in form of ribbons and rods were amorphous. Two stage crystallization process was observed for studied bulk amorphous alloy. The differences of crystallization temperature between ribbons and rods with chosen thickness are probably caused by different amorphous structures as a result of the different cooling rates in casting process. The SEM images showed that studied fractures could be classified as mixed fractures with indicated two zones contained “river” and “smooth” areas. The changing of chosen soft magnetic properties (μr, Bs, Hc obtained for samples with different thickness is a result of the non-homogenous amorphous structure of tested metallic glasses. The annealing process in temperature range from 373 to 773 K causes structural relaxation of tested amorphous materials, which leads to changes in their physical properties. The qualitative

  6. Bulk and confinement-induced phase transitions in colloidal suspensions

    OpenAIRE

    Fortini, A.

    2007-01-01

    In the thesis, we have presented computer simulation results on the bulk and interfacial phase behaviour of colloidal suspensions. In the first part, we have developed and tested a simulation technique to calculate the free energy of hard-core systems. This technique was used to calculate the interfacial free energy of colloidal hard spheres and with the addition of non-adsorbing polymer coils. Good agreement was found between the simulation results and those from density functional theory. F...

  7. Introduction to bulk metallic glass composite and its recent applications

    OpenAIRE

    Lu, Shijing

    2011-01-01

    Bulk metallic glass (BMG) materials are hot topics in recent years, not to mention BMG matrix composites, which further improve the magnetic and mechanical properties of BMG materials. BMG and BMG matrix materials are fast developing and promising materials in modern industry due to their extraordinary properties such as high strength, low density, excellent resistibility to high temperature and corrosion. In this paper, I reviewed processing and application of several recently developed BMG ...

  8. Dynamic coupling of bulk chemistry, trace elements and mantle flow

    Science.gov (United States)

    Davies, J. H.; Heck, H. V.; Nowacki, A.; Wookey, J. M.; Elliott, T.; Porcelli, D.

    2015-12-01

    Fully dynamical models that not only track the evolution of chemical heterogeneities through the mantle, but also incorporate the effect of chemical heterogeneities on the dynamics of mantle convection are now emerging. Since in general analytical solutions to these complex problems are lacking, careful testing and investigations of the effect and usefulness of these models is needed. We extend our existing numerical mantle convection code that can track fluid flow in 3D spherical geometry and tracks both bulk chemical components (basal fraction) and different trace elements. The chemical components fractionate upon melting when and where the solidus is crossed. Now, the chemical information will effect the flow of the fluid in the following ways: The bulk composition will link to density and the (radioactive) trace element abundance to heat production. Results will be reported of the effect of different density structures; either starting with a primordial dense layer at the base of the mantle, having all density variation originate from melting (basalt production), or a combination between these two end-member scenarios. In particular we will focus on the connection between large scale bulk chemical structures in the (deep) mantle and the evolution of the distribution of noble gasses (He and Ar). The distribution of noble gasses depend upon 1) assumptions on the initial distributions in the mantle, 2) the mantle flow, 3) radioactive production and, 4) outgassing to the atmosphere upon melting close to the surface.

  9. Extreme Water: Characterizing Exoplanets with Excess Bulk Water Interiors

    Science.gov (United States)

    Sasselov, Dimitar

    2015-12-01

    A number of planets with radii of 1 - 2.5 Earth radius have measured mean densities that allow more than 20% of their bulk interior to be composed of water. How do planets with solid-state water mantles modulate the fluxes of gases reaching the surface? What should we expect about the composition of their evolved atmospheres? I review theoretical models of the interiors and near-surface layers that constrain the fluxes of major gases (in and out) and resulting atmospheric compositions. The results have implications for observational characterization of rocky versus water planets, when the density alone is not enough, as well as the search for biosignatures and habitability.

  10. Bulk and mechanical properties of the Paintbrush tuff recovered from borehole USW NRG-6: Data report

    International Nuclear Information System (INIS)

    Experimental results are presented for bulk and mechanical properties measurements on specimens of the Paintbrush tuff recovered from borehole USW NRG-6 at Yucca Mountain, Nevada. Measurements have been performed on four thermal/mechanical units, TCw, PTn, TSw1 and TSw2. On each specimen the following bulk properties have been reported: dry bulk density, saturated bulk density, average grain density, and porosity. Unconfined compression to failure, confined compression to failure, and indirect tensile strength tests were performed on selected specimens recovered from the borehole. In addition, compressional and shear wave velocities were measured on specimens designated for unconfined compression and confined compression experiments. Measurements were conducted at room temperature on nominally water saturated specimens; however, some specimens of PTn were tested in a room dry condition. The nominal strain rate for the fracture experiments was 10-5 s -1

  11. Lung density

    DEFF Research Database (Denmark)

    Garnett, E S; Webber, C E; Coates, G;

    1977-01-01

    The density of a defined volume of the human lung can be measured in vivo by a new noninvasive technique. A beam of gamma-rays is directed at the lung and, by measuring the scattered gamma-rays, lung density is calculated. The density in the lower lobe of the right lung in normal man during quiet...... breathing in the sitting position ranged from 0.25 to 0.37 g.cm-3. Subnormal values were found in patients with emphsema. In patients with pulmonary congestion and edema, lung density values ranged from 0.33 to 0.93 g.cm-3. The lung density measurement correlated well with the findings in chest radiographs...... but the lung density values were more sensitive indices. This was particularly evident in serial observations of individual patients....

  12. Handling of bulk solids theory and practice

    CERN Document Server

    Shamlou, P A

    1990-01-01

    Handling of Bulk Solids provides a comprehensive discussion of the field of solids flow and handling in the process industries. Presentation of the subject follows classical lines of separate discussions for each topic, so each chapter is self-contained and can be read on its own. Topics discussed include bulk solids flow and handling properties; pressure profiles in bulk solids storage vessels; the design of storage silos for reliable discharge of bulk materials; gravity flow of particulate materials from storage vessels; pneumatic transportation of bulk solids; and the hazards of solid-mater

  13. Hypernormal Densities

    OpenAIRE

    Giacomini, Raffaella; Gottschling, Andreas; Haefke, Christian; White, Halbert

    2002-01-01

    We derive a new family of probability densities that have the property of closed-form integrability. This flexible family finds a variety of applications, of which we illustrate density forecasting from models of the AR-ARCH class for U.S. inflation. We find that the hypernormal distribution for the model's disturbances leads to better density forecasts than the ones produced under the assumption that the disturbances are Normal or Student's t.

  14. Ordered bulk degradation via autophagy

    DEFF Research Database (Denmark)

    Dengjel, Jörn; Kristensen, Anders Riis; Andersen, Jens S

    2008-01-01

    During amino acid starvation, cells undergo macroautophagy which is regarded as an unspecific bulk degradation process. Lately, more and more organelle-specific autophagy subtypes such as reticulophagy, mitophagy and ribophagy have been described and it could be shown, depending on the experimental...... setup, that autophagy specifically can remove certain subcellular components. We used an unbiased quantitative proteomics approach relying on stable isotope labeling by amino acids in cell culture (SILAC) to study global protein dynamics during amino acid starvation-induced autophagy. Looking...... at proteasomal and lysosomal degradation ample cross-talk between the two degradation pathways became evident. Degradation via autophagy appeared to be ordered and regulated at the protein complex/organelle level. This raises several important questions such as: can macroautophagy itself be specific and what...

  15. Microwave disinfestation of bulk timber.

    Science.gov (United States)

    Plaza, Pedro Jose; Zona, Angela Tatiana; Sanchís, Raul; Balbastre, Juan Vicente; Martínez, Antonio; Muñoz, Eva Maria; Gordillo, Javier; de los Reyes, Elías

    2007-01-01

    In this paper a complete microwave system for bulk timber disinfestation is developed and tested. A commercial FEM simulator has been used to design the applicator, looking for structures providing uniform field distributions, which is a factor of capital relevance for a successful treatment. Special attention has also been given to the reduction of electromagnetic energy leakage. A dual polarized cylindrical applicator with a corrugated flange has been designed. The applicator has also been numerically tested emulating some real-life operating conditions. A prototype has been built using two low-cost magnetrons of 900 W and high power coaxial cables and it has been tested inside a shielded semianechoic chamber. The tests have been carried out in three stages: validation of the applicator design, determination of the lethal dosage as a function of the insect position and the maximum wood temperature allowed and statement of safe operation procedures. PMID:18351001

  16. Higher order bulk characteristic parameters of asymmetric nuclear matter

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The bulk parameters characterizing the energy of symmetric nuclear matter and the symmetry energy defined at normal nuclear density ρ0 provide important information on the equation of state (EOS) of isospin asymmetric nuclear matter. While significant progress has been made in determining some lower order bulk characteristic parameters, such as the energy E0(ρ0) and incompress ibility K0 of symmetric nuclear matter as well as the symmetry energy Esym(ρ0) and its slope parameter L, yet the higher order bulk characteristic parameters are still poorly known. Here, we analyze the correlations between the lower and higher order bulk char acteristic parameters within the framework of Skyrme Hartree-Fock energy density functional and then estimate the values of some higher order bulk characteristic parameters. In particular, we obtain J0 = (-355±95) MeV and I0 = (1473±680) MeV for the third order and fourth-order derivative parameters of symmetric nuclear matter at ρ0 and Ksym = (-100 ± 165) MeV, Jsym = (224 ± 385) MeV, Isym = (-1309 ± 2025) MeV for the curvature parameter, third-order and fourth-order derivative parameters of the symmetry energy at ρ0, using the empirical constraints on E0(ρ0), K0, Esym(ρ0), L, and the isoscalar and isovector nucleon effective masses. Furthermore, our results indicate that the three parameters E0(ρ0), K0, and J0 can reasonably characterize the EOS of symmetric nuclear matter up to 2ρ0 while the symmetry energy up to 2ρ0 can be well described by Esym(ρ0), L, and Ksym.

  17. Isotopic signatures by bulk analyses

    International Nuclear Information System (INIS)

    Los Alamos National Laboratory has developed a series of measurement techniques for identification of nuclear signatures by analyzing bulk samples. Two specific applications for isotopic fingerprinting to identify the origin of anthropogenic radioactivity in bulk samples are presented. The first example is the analyses of environmental samples collected in the US Arctic to determine the impact of dumping of radionuclides in this polar region. Analyses of sediment and biota samples indicate that for the areas sampled the anthropogenic radionuclide content of sediments was predominantly the result of the deposition of global fallout. The anthropogenic radionuclide concentrations in fish, birds and mammals were very low. It can be surmised that marine food chains are presently not significantly affected. The second example is isotopic fingerprinting of water and sediment samples from the Rocky Flats Facility (RFP). The largest source of anthropogenic radioactivity presently affecting surface-waters at RFP is the sediments that are currently residing in the holding ponds. One gram of sediment from a holding pond contains approximately 50 times more plutonium than 1 liter of water from the pond. Essentially 100% of the uranium in Ponds A-1 and A-2 originated as depleted uranium. The largest source of radioactivity in the terminal Ponds A-4, B-5 and C-2 was naturally occurring uranium and its decay product radium. The uranium concentrations in the waters collected from the terminal ponds contained 0.05% or less of the interim standard calculated derived concentration guide for uranium in waters available to the public. All of the radioactivity observed in soil, sediment and water samples collected at RFP was naturally occurring, the result of processes at RFP or the result of global fallout. No extraneous anthropogenic alpha, beta or gamma activities were detected. The plutonium concentrations in Pond C-2 appear to vary seasonally

  18. Large-scale HTS bulks for magnetic application

    Energy Technology Data Exchange (ETDEWEB)

    Werfel, Frank N., E-mail: werfel@t-online.de [Adelwitz Technologiezentrum GmbH (ATZ), Rittergut Adelwitz 16, 04886 Arzberg-Adelwitz (Germany); Floegel-Delor, Uta; Riedel, Thomas; Goebel, Bernd; Rothfeld, Rolf; Schirrmeister, Peter; Wippich, Dieter [Adelwitz Technologiezentrum GmbH (ATZ), Rittergut Adelwitz 16, 04886 Arzberg-Adelwitz (Germany)

    2013-01-15

    Highlights: ► ATZ Company has constructed about 130 HTS magnet systems. ► Multi-seeded YBCO bulks joint the way for large-scale application. ► Levitation platforms demonstrate “superconductivity” to a great public audience (100 years anniversary). ► HTS magnetic bearings show forces up to 1 t. ► Modular HTS maglev vacuum cryostats are tested for train demonstrators in Brazil, China and Germany. -- Abstract: ATZ Company has constructed about 130 HTS magnet systems using high-Tc bulk magnets. A key feature in scaling-up is the fabrication of YBCO melts textured multi-seeded large bulks with three to eight seeds. Except of levitation, magnetization, trapped field and hysteresis, we review system engineering parameters of HTS magnetic linear and rotational bearings like compactness, cryogenics, power density, efficiency and robust construction. We examine mobile compact YBCO bulk magnet platforms cooled with LN{sub 2} and Stirling cryo-cooler for demonstrator use. Compact cryostats for Maglev train operation contain 24 pieces of 3-seed bulks and can levitate 2500–3000 N at 10 mm above a permanent magnet (PM) track. The effective magnetic distance of the thermally insulated bulks is 2 mm only; the stored 2.5 l LN{sub 2} allows more than 24 h operation without refilling. 34 HTS Maglev vacuum cryostats are manufactured tested and operate in Germany, China and Brazil. The magnetic levitation load to weight ratio is more than 15, and by group assembling the HTS cryostats under vehicles up to 5 t total loads levitated above a magnetic track is achieved.

  19. Densities, Spectral Densities and Modality

    OpenAIRE

    Davies, PL Laurie; Kovac, A.

    2002-01-01

    This paper considers the problem of specifying a simple approximating density function for a given data set (x1,…,xn). Simplicity is measured by the number of modes but several different definitions of approximation are introduced. The taut string method is used to control the numbers of modes and to produce candidate approximating densities. Refinements are introduced that improve the local adaptivity of the procedures and the method is extended to spectral densities.

  20. Probing bulk defect energy bands using generalized charge pumping method

    Science.gov (United States)

    Masuduzzaman, Muhammad; Weir, Bonnie; Alam, Muhammad Ashraful

    2012-04-01

    The multifrequency charge pumping (CP) technique has long been used to probe the density of defects at the substrate-oxide interface, as well as in the bulk of the oxide of MOS transistors. However, profiling the energy levels of the defects has been more difficult due to the narrow scanning range of the voltage of a typical CP signal, and the uncertainty associated with the defect capture cross-section. In this paper, we discuss a generalized CP method that can identify defect energy bands within a bulk oxide, without requiring separate characterization of the defect capture cross-section. We use the new technique to characterize defects in both fresh and stressed samples of various dielectric compositions. By quantifying the way defects are generated as a function of time, we gain insight into the nature of defect generation in a particular gate dielectric. We also discuss the relative merits of voltage, time, and other variables of CP to probe bulk defect density, and compare the technique with related characterization approaches.

  1. Bulk and shear viscosities of hot and dense hadron gas

    International Nuclear Information System (INIS)

    We estimate the bulk and the shear viscosity at finite temperature and baryon densities of hadronic matter within a hadron resonance gas model which includes a Hagedorn spectrum. The parameters of the Hagedorn spectrum are adjusted to fit recent lattice QCD simulations at finite chemical potential. For the estimation of the bulk viscosity we use low energy theorems of QCD for the energy momentum tensor correlators. For the shear viscosity coefficient, we estimate the same using molecular kinetic theory to relate the shear viscosity coefficient to average momentum of the hadrons in the hot and dense hadron gas. The bulk viscosity to entropy ratio increases with chemical potential and is related to the reduction of velocity of sound at nonzero chemical potential. The shear viscosity to entropy ratio on the other hand, shows a nontrivial behavior with the ratio decreasing with chemical potential for small temperatures but increasing with chemical potential at high temperatures and is related to decrease of entropy density with chemical potential at high temperature due to finite volume of the hadrons

  2. 黄土区小流域土壤容重和饱和导水率的时空动态特征%Spatio-temporal characteristics of soil bulk density and saturated hydraulic conductivity at small watershed scale on Loess Plateau

    Institute of Scientific and Technical Information of China (English)

    傅子洹; 王云强; 安芷生

    2015-01-01

    Surface soil bulk density (BD) and saturated hydraulic conductivity are two of important parameters to assess rainfall infiltration, runoff formation and soil erosion. But little research has been done at a watershed scale. On the Loess Plateau of China, investigations on the spatio-temporal changes of BD and saturated hydraulic conductivity at a small watershed scale are essential for regional ecological restoration and may enrich our understanding on the related eco-hydrolgical processes. In this study, we measured BD and saturated hydraulic conductivity in August, September, and October of 2014 at 73 sites that were pre-located by using Global Positioning System in a 50 m × 50 m grid at the LaoYeManQu watershed on the wind-water erosion crisscross region of the Chinese Loess Plateau. Using classical statistical and geostatistical methods, we characterized and compared the spatial and temporal changes of BD and saturated hydraulic conductivity. The semivariograms and kriging method included in the geostatistical method were used to reflect the visual variation among different months from August to October. Results showed that: 1) Among the three months, BD had a normal distribution and exhibited a time stability while saturated hydraulic conductivity had a skewed distribution and varied greatly. BD variation was smaller than that of the saturated hydraulic conductivity at the watershed scale. 2) Semivariograms of BD and saturated hydraulic conductivity from August to October could be best fitted by an isotropic exponential model. Both BD and saturated hydraulic conductivity exhibited a moderate spatial dependence. Distribution maps produced by kriging indicated pronounced spatial patterns of BD and saturated hydraulic conductivity at the small watershed—at the slope top and the western part of the watershed, BD demonstrated an increasing trend while saturated hydraulic conductivity decreased gradually from August to October. 3) Pearson correlation analysis

  3. Arithmetic density

    CERN Document Server

    Garay, Mauricio

    2012-01-01

    Arithmetic class are closed subsets of the euclidean space which generalise arithmetical conditions encoutered in dynamical systems, such as diophantine conditions or Bruno type conditions. I prove density estimates for such sets using Dani-Kleinbock-Margulis techniques.

  4. Relative entropy equals bulk relative entropy

    CERN Document Server

    Jafferis, Daniel L; Maldacena, Juan; Suh, S Josephine

    2015-01-01

    We consider the gravity dual of the modular Hamiltonian associated to a general subregion of a boundary theory. We use it to argue that the relative entropy of nearby states is given by the relative entropy in the bulk, to leading order in the bulk gravitational coupling. We also argue that the boundary modular flow is dual to the bulk modular flow in the entanglement wedge, with implications for entanglement wedge reconstruction.

  5. Coupling brane fields to bulk supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Parameswaran, Susha L. [Uppsala Univ. (Sweden). Theoretical Physics; Schmidt, Jonas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2010-12-15

    In this note we present a simple, general prescription for coupling brane localized fields to bulk supergravity. We illustrate the procedure by considering 6D N=2 bulk supergravity on a 2D orbifold, with brane fields localized at the fixed points. The resulting action enjoys the full 6D N=2 symmetries in the bulk, and those of 4D N=1 supergravity at the brane positions. (orig.)

  6. Coupling brane fields to bulk supergravity

    International Nuclear Information System (INIS)

    In this note we present a simple, general prescription for coupling brane localized fields to bulk supergravity. We illustrate the procedure by considering 6D N=2 bulk supergravity on a 2D orbifold, with brane fields localized at the fixed points. The resulting action enjoys the full 6D N=2 symmetries in the bulk, and those of 4D N=1 supergravity at the brane positions. (orig.)

  7. Diagnosis of Dry Bulk Shipping Market

    Institute of Scientific and Technical Information of China (English)

    Wendy Wu

    2009-01-01

    @@ A sudden severe winter for dry bulk shipping market Since the second half of last year,dry bulk shipping market experienced a sudden and dramatical change which caught everyone off guard in just a few months'time.As the wind vane of dry bulk shipping market,BDI index(Baltic index)has been climbing higher and higher from the middle of 2005.It began to nearly shoot up into the 2007.

  8. Bulk scalar field in DGP braneworld cosmology

    CERN Document Server

    Ansari, Rizwan ul Haq

    2007-01-01

    We investigated the effects of bulk scalar field in the braneworld cosmological scenario. The Friedmann equations and acceleration condition in presence of the bulk scalar field for a zero tension brane and cosmological constant are studied. In DGP model the effective Einstein equation on the brane is obtained with bulk scalar field. The rescaled bulk scalar field on the brane in the DGP model behaves as an effective four dimensional field, thus standard type cosmology is recovered. In present study of the DGP model, the late-time accelerating phase of the universe can be explained .

  9. Bianchi Type-Ⅰ Cosmology with Cosmic String and Bulk Viscosity

    Institute of Scientific and Technical Information of China (English)

    王行翔

    2003-01-01

    Some locally rotationally symmetric Bianchi type-Ⅰ cosmological solutions for a cloud string with bulk viscosity are presented. In the first case, an equation of state p = kλ and the relation between metric potentials R = ASn are considered, and the solution represents shearing non-rotating model with the bulk viscosity ζ∝ p1/2, where p is the rest energy density of the cloud of strings with particles attached to them, λ is the tension density of the cloud of strings, ζ is the coeffcient of the bulk viscosity, R and S are only the functions of time t, while A and k are constant. In the second case, the constant coefficient of bulk viscosity is considered.

  10. Second order closure for stratified convection: bulk region and overshooting

    CERN Document Server

    Biferale, L; Sbragaglia, M; Scagliarini, A; Toschi, F; Tripiccione, R

    2011-01-01

    The parameterization of small-scale turbulent fluctuations in convective systems and in the presence of strong stratification is a key issue for many applied problems in oceanography, atmospheric science and planetology. In the presence of stratification, one needs to cope with bulk turbulent fluctuations and with inversion regions, where temperature, density -or both- develop highly non-linear mean profiles due to the interactions between the turbulent boundary layer and the unmixed -stable- flow above/below it. We present a second order closure able to cope simultaneously with both bulk and boundary layer regions, and we test it against high-resolution state-of-the-art 2D numerical simulations in a convective and stratified belt for values of the Rayleigh number, up to Ra = 10^9. Data are taken from a Rayleigh-Taylor system confined by the existence of an adiabatic gradient.

  11. Appearance of the bulk motif in Al clusters

    Science.gov (United States)

    Sun, Jiao; Lu, Wen-Cai; Li, Ze-Sheng; Wang, C. Z.; Ho, K. M.

    2008-07-01

    We have performed an unbiased search for the lowest-energy structures of medium-sized aluminum clusters Aln (n=19-26) using a genetic algorithm (GA) coupled with a tight-binding interatomic potential. Structural candidates obtained from our GA search were further optimized using density functional theory. It is found that the double icosahedron is not the most stable structure for Al19 but serves as the core for Al20 and Al21. The lowest-energy structures of Aln are found to undergo a transition to an aluminum bulk motif above Al23. In particular, the lowest-energy structure of Al26 is almost a fragment of the bulk face-centered-cubic crystal except for the stacking fault at the bottom layer. Anion clusters were also studied.

  12. Low Bone Density

    Science.gov (United States)

    ... Density Exam/Testing › Low Bone Density Low Bone Density Low bone density is when your bone density ... people with normal bone density. Detecting Low Bone Density A bone density test will determine whether you ...

  13. Bulk-Boundary interaction and the second law in Ho\\v{r}ava-Lifshitz cosmology

    CERN Document Server

    Cruz, Miguel; Peña, Francisco

    2015-01-01

    By defining $Q$ as a function which realizes the energy transference between the bulk and the boundary of spacetime, as we interprete it here in the framework of Ho\\v{r}ava-Lifshitz (HL) cosmology, flat case, we discuss the validity of the second law of thermodynamics in the light of the sign changes of $Q$ (changes in the direction of energy transference) and its consequences through the cosmic evolution, in particular, whether the thermal equilibrium between bulk and boundary is reached or not. Additionally, we discuss possible phase transitions experienced by the bulk and the boundary (seen as sign changes in their heat capacities) through the cosmic evolution. The energy density in the bulk is modeled under an holographic perspective. As far as we know, currently there is not observational data on bulk-boundary interaction.

  14. Phenomenological Consequences of Enhanced Bulk Viscosity Near the QCD Critical Point

    CERN Document Server

    Monnai, Akihiko; Yin, Yi

    2016-01-01

    In the proximity of the QCD critical point the bulk viscosity of quark-gluon matter is expected to be proportional to nearly the third power of the critical correlation length, and become significantly enhanced. This work is the first attempt to study the phenomenological consequences of enhanced bulk viscosity near the QCD critical point. For this purpose, we implement the expected critical behavior of the bulk viscosity within a non-boost-invariant, longitudinally expanding $1+1$ dimensional causal relativistic hydrodynamical evolution at non-zero baryon density. We demonstrate that the critically-enhanced bulk viscosity induces a substantial non-equilibrium pressure, effectively softening the equation of state, and leads to sizable effects in the flow velocity and single particle distributions at the freeze-out. The observable effects that may arise due to the enhanced bulk viscosity in the vicinity of the QCD critical point can be used as complimentary information to facilitate searches for the QCD critic...

  15. Bulk Properties of Iron Isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Algin, E; Schiller, A; Voinov, A; Agvannluvsan, U; Belgya, T; Bernstein, L; Brune, C; Chankova, R; Garrett, P; Grimes, S; Guttormsen, M; Hjorth-Jensen, M; Hornish, M; Johnson, C; Massey, T; Mitchell, G; Rekstad, J; Siem, S; Younes, W

    2006-07-27

    Nuclear level densities and radiative strength functions (RSF) in {sup 56}Fe and {sup 57}Fe were measured using the {sup 57}Fe({sup 3}He,{alpha}{gamma}) and {sup 57}Fe({sup 3}He, {sup 3}He{prime}{gamma}) reactions, respectively, at Oslo Cyclotron Laboratory. A low-energy enhancement in the RSF below 4 MeV energy was observed. This finding cannot be explained by common theoretical models. In a second experiment, two-step cascade intensities with soft primary transitions from the {sup 56}Fe(n,2{gamma}) reaction were measured. The agreement between the two experiments confirms the low-energy enhancement in the RSF. In a third experiment, the neutron evaporation spectrum from the {sup 55}Mn(dn,N){sup 56}Fe reaction was measured at 7-MeV deuteron energy at John Edwards Accelerator Laboratory at Ohio University. Comparison of the level density of {sup 56}Fe obtained from the first and third experiments gives an overall good agreement. Furthermore, observed enhancement for soft {gamma} rays is supported by the last experiment.

  16. Cylindrically symmetric cosmological model in the presence of bulk stress with varying $\\Lambda$

    Indian Academy of Sciences (India)

    V G METE; A S NIMKAR; V D ELKAR

    2016-10-01

    Cylindrically symmetric non-static space–time is investigated in the presence of bulk stress given by Landau and Lifshitz. To get a solution, a supplementary condition between metric potentials is used. The viscosity coefficient of the bulk viscous fluid is assumed to be a power function of mass density whereas the coefficient of shear viscosity is considered as proportional to the scale of expansion in the model. Also some physical and geometrical properties of the model are discussed.

  17. Superhard MgB sub 2 bulk material prepared by high-pressure sintering

    CERN Document Server

    Ma, H A; Chen, L X; Zhu, P W; Ren, G Z; Guo, W L; Fu, X Q; Zou Guang Tian; Ren, Z A; Che, G C; Zhao, Z X

    2002-01-01

    Superhard MgB sub 2 bulk material with a golden metallic shine was synthesized by high-pressure sintering for 8 h at 5.5 GPa and different temperatures. Appropriate pressure and temperature conditions for synthesizing polycrystalline MgB sub 2 with high hardness were investigated. The samples were characterized by means of atomic force microscopy and x-ray diffraction. The Vickers hardness, bulk density, and electrical resistivity were measured at room temperature.

  18. 27 CFR 20.191 - Bulk articles.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bulk articles. 20.191... Users of Specially Denatured Spirits Operations by Users § 20.191 Bulk articles. Users who convey articles in containers exceeding one gallon may provide the recipient with a photocopy of subpart G of...

  19. Shifting densities

    OpenAIRE

    Mille, Matthieu

    2000-01-01

    In this paper, the author adopt a time-geography approach to examine the temporal variation of urban density by analysing spatial load changes at different times of the day at the communal and community level. The evolution of means of transport coupled with the abandon of the notion of direct proximity to the urban dwelling place provide the basis for this new approach to the study of urban densities. The shift towards spatial specialisation within cities has lead to radical changes in the f...

  20. Bulk equations of motion from CFT correlators

    CERN Document Server

    Kabat, Daniel

    2015-01-01

    To O(1/N) we derive, purely from CFT data, the bulk equations of motion for interacting scalar fields and for scalars coupled to gauge fields and gravity. We first uplift CFT operators to mimic local AdS fields by imposing bulk microcausality. This requires adding an infinite tower of smeared higher-dimension double-trace operators to the CFT definition of a bulk field, with coefficients that we explicitly compute. By summing the contribution of the higher-dimension operators we derive the equations of motion satisfied by these uplifted CFT operators and show that we precisely recover the expected bulk equations of motion. We exhibit the freedom in the CFT construction which corresponds to bulk field redefinitions.

  1. Bulk limited conduction in electroluminescent polymer devices

    Science.gov (United States)

    Campbell, A. J.; Weaver, M. S.; Lidzey, D. G.; Bradley, D. D. C.

    1998-12-01

    The current-voltage (J-V) characteristics of ITO/polymer film/Al or Au structures of poly(phenylene vinylene) (PPV) and a dialkoxy PPV copolymer have been recorded for a range of different film thickness d and temperatures T. At high applied bias all the characteristics can be fitted over a given range to a power law J=KVm, where m increases with decreasing T, log(K) is proportional to m, and K is proportional to d-α m, where α˜2 (ITO/polymer film/Al devices) and ˜1 (ITO/polymer film/Au devices). Different single carrier space charge limited conduction theories have been used to try and explain this behavior. The analytical theory in which the carrier density is decreased by an exponential trap distribution lying below effectively isoelectronic transport states is in good agreement, but cannot explain the thickness dependence of the ITO/polymer film/Au devices and can be criticized as being physically unreasonable. A numerical analysis in which the mobility has the field and temperature dependence found for hopping transport in disordered systems is also in good agreement, but can only fit a small range of J and cannot explain the magnitude of K, the temperature dependence of m or the abrupt change in slope in the J-V characteristics with increasing bias. Mixed models are equally good but cannot explain the deviations from experiment. We consider that further experimental studies of carrier mobilities and the nature of the traps present in such materials is required to distinguish between these models and resolve the nature of bulk limited conduction in conjugated polymers.

  2. Effect of metal impregnation in the field cool magnetization of bulk superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Kita, M. [Superconductivity Research Laboratory, ISTEC, 1-10-13 Shinonome, Koto-ku, Tokyo 135-0062 (Japan)]. E-mail: kita@istec.or.jp; Nariki, S. [Superconductivity Research Laboratory, ISTEC, 1-10-13 Shinonome, Koto-ku, Tokyo 135-0062 (Japan); Sakai, N. [Superconductivity Research Laboratory, ISTEC, 1-10-13 Shinonome, Koto-ku, Tokyo 135-0062 (Japan); Hirabayashi, I. [Superconductivity Research Laboratory, ISTEC, 1-10-13 Shinonome, Koto-ku, Tokyo 135-0062 (Japan)

    2006-10-01

    Gd-Ba-Cu-O bulk superconductors have significant potential for various applications due to the high critical current density and the highly trapped magnetic fields. Recently we have developed a large sized bulk superconductor using Gd210, which is discovered in the microgravity experiment. We investigated the mechanical properties and the cryostability of the Gd-Ba-Cu-O bulk superconductor to determine how to improve toughness and heat conduction of the large sized bulk superconductor. We introduced a stainless ring around the circumference of the bulk to increase the fracture strength of the bulk. Also, we introduced Al wires inserted in the hole along the c-axis of the bulk, and then the sample was subjected to the impregnation by using Bi-Sn-Cd alloy. We measured the trapped magnetic fields and the repulsive forces of the samples. The trapped magnetic field distributions were 1.13-1.36 T. The repulsive forces at 1 mm gap between the sample bulk and the permanent magnet with the surface magnetic induction of 0.37 T were about 70 N at 77 K. We have also measured the temperature dependence of the trapped magnetic field, and confirmed the effect of metal impregnation.

  3. Pulsed-field magnetization of a bulk superconductor with small holes

    International Nuclear Information System (INIS)

    Highlights: ► We propose the bulk material with small holes which makes the role of a flux path. ► The flux is supplied to the bulk reducing heat generation by the artificial path. ► The validity is investigated by the fundamental test of a single pulse application. ► It was confirmed that the magnetic flux penetrated even with a low applied field. ► Flux flow was small in a high applied field compared with a usual hole-less bulk. -- Abstract: Recent enlargement of the size and the performance enhancement of bulk superconductor lead to the difficulty of magnetic flux trapping by a pulsed-field magnetization. This paper proposes the bulk material with small holes which makes the role of an artificial magnetic flux path to supply the flux in the bulk. The fundamental experiment of applying a single pulsed-field with varying amplitudes was carried out using a ∅60 mm × 20 mm GdBa2Cu3O7−x bulk material with four ∅2 mm holes filled up with solder. Compared with a usual hole-less bulk, the total magnetic flux and the maximum trapped flux density were greatly increased in a low applied field. Moreover, those large reduction caused by flux flow was suppressed in a high applied field

  4. Nongeneric dispersion of excitons in the bulk of WSe2

    Science.gov (United States)

    Schuster, R.; Wan, Y.; Knupfer, M.; Büchner, B.

    2016-08-01

    We combine electron energy-loss spectroscopy (EELS) and density functional theory (DFT) calculations to study the dispersion and effective mass of excitons in the bulk of WSe2. Our EELS data suggest substantial deviations from the generic quadratic momentum dependence along the Γ K direction. From the DFT-derived Kohn-Sham states we deduce the EELS response without the inclusion of particle-hole attraction to study the possible role of the single-particle band structure on the exciton behavior. Based on this analysis we argue in favor of a strongly momentum dependent particle-hole interaction in WSe2 and other group-VI-transition-metal dichalcogenides.

  5. Ductilizing Bulk Metallic Glass Composite by Tailoring Stacking Fault Energy

    Science.gov (United States)

    Wu, Y.; Zhou, D. Q.; Song, W. L.; Wang, H.; Zhang, Z. Y.; Ma, D.; Wang, X. L.; Lu, Z. P.

    2012-12-01

    Martensitic transformation was successfully introduced to bulk metallic glasses as the reinforcement micromechanism. In this Letter, it was found that the twinning property of the reinforcing crystals can be dramatically improved by reducing the stacking fault energy through microalloying, which effectively alters the electron charge density redistribution on the slipping plane. The enhanced twinning propensity promotes the martensitic transformation of the reinforcing austenite and, consequently, improves plastic stability and the macroscopic tensile ductility. In addition, a general rule to identify effective microalloying elements based on their electronegativity and atomic size was proposed.

  6. Microwave losses of bulk CaC 6

    Science.gov (United States)

    Cifariello, G.; Di Gennaro, E.; Lamura, G.; Andreone, A.; Emery, N.; Hérold, C.; Marêché, J. F.; Lagrange, P.

    2007-09-01

    We report a study of the temperature dependence of the surface resistance RS in the graphite intercalated compound (GIC) CaC6, where superconductivity at 11.5 K was recently discovered. Experiments are carried out using a copper dielectrically loaded cavity operating at 7 GHz in a "hot finger" configuration. Bulk CaC6 samples have been synthesized from highly oriented pyrolytic graphite. Microwave data allow to extract unique information on the quasiparticle density and on the nature of pairing in superconductors. The analysis of RS(T) confirms our recent experimental findings that CaC6 behaves as a weakly-coupled, fully gapped, superconductor.

  7. Holographic representation of local bulk operators

    CERN Document Server

    Hamilton, A; Lifschytz, G; Lowe, D A; Hamilton, Alex; Kabat, Daniel; Lifschytz, Gilad; Lowe, David A.

    2006-01-01

    The Lorentzian AdS/CFT correspondence implies a map between local operators in supergravity and non-local operators in the CFT. By explicit computation we construct CFT operators which are dual to local bulk fields in the semiclassical limit. The computation is done for general dimension in global, Poincare and Rindler coordinates. We find that the CFT operators can be taken to have compact support in a region of the complexified boundary whose size is set by the bulk radial position. We show that at finite N the number of independent commuting operators localized within a bulk volume saturates the holographic bound.

  8. Bulk viscosity in holographic Lifshitz hydrodynamics

    OpenAIRE

    Carlos Hoyos; Bom Soo Kim; Yaron Oz

    2014-01-01

    We compute the bulk viscosity in holographic models dual to theories with Lifshitz scaling and/or hyperscaling violation, using a generalization of the bulk viscosity formula derived in arXiv:1103.1657 from the null focusing equation. We find that only a class of models with massive vector fields are truly Lifshitz scale invariant, and have a vanishing bulk viscosity. For other holographic models with scalars and/or massless vector fields we find a universal formula in terms of the dynamical ...

  9. Bulk viscosity in holographic Lifshitz hydrodynamics

    International Nuclear Information System (INIS)

    We compute the bulk viscosity in holographic models dual to theories with Lifshitz scaling and/or hyperscaling violation, using a generalization of the bulk viscosity formula derived in arXiv:1103.1657 from the null focusing equation. We find that only a class of models with massive vector fields are truly Lifshitz scale invariant, and have a vanishing bulk viscosity. For other holographic models with scalars and/or massless vector fields we find a universal formula in terms of the dynamical exponent and the hyperscaling violation exponent

  10. Bulk viscosity of hot and dense hadrons

    International Nuclear Information System (INIS)

    The bulk viscosity of hot and dense hadrons has been estimated within the framework of hadronic resonance gas model. We observe that the bulk viscosity to entropy ratio increases faster with temperature for higher μB. The magnitude of ζ is more at high μB. This results will have crucial importance for fire-ball produced at low energy nuclear collisions (FAIR, NICA). We note that the bulk to shear viscosity ratio remains above the bound set by AdS/CFT

  11. Preparation and Characterization of Copper-Nickel Bulk Nanocrystals

    Institute of Scientific and Technical Information of China (English)

    WU Xiaoqiang; TANG Yongjian; WANG Lan; AN Xuguang; YI Zao; SUN Weiguo

    2014-01-01

    Copper-nickel nanoparticle was directly prepared by flow-levitation method (FL) and sintered by vacuum sintering of powder (VSP) method. Several characterizations, such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), differential thermal analysis (DTA), and energy-dispersive X-ray spectroscopy (EDX) were used to investigate the prepared nanostructures. The results of the study show that FL method could prepare high purity Cu-Ni nanocrystals of uniform spheres with size distribution between 20 and 90 nm. After sintering the bulk nanocrystalline copper-nickel has obvious thermal stability and the surface Webster hardness increases with the rising sintering temperature. At the temperature of 900℃, the specimen shows higher surface Webster hardness, which is about two times of traditional materials. When the sintering temperature arrives at 1 000℃the relative density of bulk nanocrystals can reach 97.86 percent. In this paper, the variation tendency of porosity, phase and particles size of bulk along with the changing of sintering temperature have been studied.

  12. Phase diagram of a bulk 1d lattice Coulomb gas

    Science.gov (United States)

    Démery, V.; Monsarrat, R.; Dean, D. S.; Podgornik, R.

    2016-01-01

    The exact solution, via transfer matrix, of the simple one-dimensional lattice Coulomb gas (1d LCG) model can reproduce peculiar features of ionic liquid capacitors, such as overscreening, layering, and camel- and bell-shaped capacitance curves. Using the same transfer matrix method, we now compute the bulk properties of the 1d LCG in the constant voltage ensemble. We unveil a phase diagram with rich structure exhibiting low-density disordered and high-density ordered phases, separated by a first-order phase transition at low temperature; the solid state at full packing can be ordered or not, depending on the temperature. This phase diagram, which is strikingly similar to its three-dimensional counterpart, also sheds light on the behaviour of the confined system.

  13. Bulk band structure of Bi2Te3

    DEFF Research Database (Denmark)

    Michiardi, Matteo; Aguilera, Irene; Bianchi, Marco;

    2014-01-01

    The bulk band structure of Bi2Te3 has been determined by angle-resolved photoemission spectroscopy and compared to first-principles calculations. We have performed calculations using the local density approximation (LDA) of density functional theory and the one-shot GW approximation within the all......-electron full-potential linearized augmented-plane-wave (FLAPW) formalism, fully taking into account spin-orbit coupling. Quasiparticle effects produce significant changes in the band structure of Bi2Te3 when compared to LDA. Experimental and calculated results are compared in the spectral regions where...... distinct differences between the LDA and GW results are present. Overall a superior agreement with GW is found, highlighting the importance of many-body effects in the band structure of this family of topological insulators....

  14. Randall-Sundrum II cosmology, AdS/CFT, and the bulk black hole

    Science.gov (United States)

    Hebecker, A.; March-Russell, J.

    2001-08-01

    We analyse the cosmology of a brane world model where a single brane carrying the standard model fields forms the boundary of a 5-dimensional AdS bulk (the Randall-Sundrum II scenario). We focus on the thermal radiation of bulk gravitons, the formation of the bulk black hole, and the holographic AdS/CFT definition of the RSII theory. Our detailed calculation of bulk radiation reduces previous estimates to a phenomenologically acceptable, although potentially visible level. In late cosmology, in which the Friedmann equation depends linearly on the energy density /ρ, only about 1% of energy density is lost to the black hole or, equivalently, to the `dark radiation' (Ωd,N~=0.01 at nucleosynthesis). The preceding, unconventional ρ2 period can produce up to 10% dark radiation (Ωd,Ncorrection to the standard treatment at low matter density. However, the 4-dimensional effective theory of CFT /+ gravity breaks down due to higher curvature terms for energy densities where ρ2 behaviour in the Friedmann equation is usually predicted. We emphasize that, in going beyond this energy density, the microscopic formulation of the theory becomes essential. For example, the pure AdS5 and string-motivated AdS5×S5 definitions differ in their cosmological implications.

  15. Randall-Sundrum II cosmology, AdS/CFT, and the bulk black hole

    International Nuclear Information System (INIS)

    We analyse the cosmology of a brane world model where a single brane carrying the standard model fields forms the boundary of a 5-dimensional AdS bulk (the Randall-Sundrum II scenario). We focus on the thermal radiation of bulk gravitons, the formation of the bulk black hole, and the holographic AdS/CFT definition of the RSII theory. Our detailed calculation of bulk radiation reduces previous estimates to a phenomenologically acceptable, although potentially visible level. In late cosmology, in which the Friedmann equation depends linearly on the energy density ρ, only about 1% of energy density is lost to the black hole or, equivalently, to the 'dark radiation' (Ωd,N≅0.01 at nucleosynthesis). The preceding, unconventional ρ2 period can produce up to 10% dark radiation (Ωd,N 2 correction to the standard treatment at low matter density. However, the 4-dimensional effective theory of CFT + gravity breaks down due to higher curvature terms for energy densities where ρ2 behaviour in the Friedmann equation is usually predicted. We emphasize that, in going beyond this energy density, the microscopic formulation of the theory becomes essential. For example, the pure AdS5 and string-motivated AdS5xS5 definitions differ in their cosmological implications

  16. The bulk radio expansion of Cassiopeia A

    International Nuclear Information System (INIS)

    Comparison, in the visibility plane, or radio observations of Cassiopeia A made at 151 MHz over a 2.3 yr interval indicates that the bulk of the radio emitting material has not been decelerated strongly

  17. PHONON ECHOES IN BULK AND POWDERED MATERIALS

    OpenAIRE

    Kajimura, K.

    1981-01-01

    Experimental and theoretical studies of phonon echoes in bulk and powdered materials are reviewed. Phonon echoes have been observed in many materials such as bulk piezoelectric crystals, paramagnets, glasses, doped semiconductors, and piezoelectric, magnetic, and metallic powders, etc. The echoes arise from a time reversal of the phase, like spin echoes, of a primary pulsed acoustic excitation due to a second acoustic or rf pulse. The phase reversal occurs through the nonlinear interactions o...

  18. Fabrication of ternary Ca-Mg-Zn bulk metallic glasses

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2013-02-01

    Full Text Available Purpose: The paper describes the preparation, structure and thermal properties of ternary Ca-Mg-Zn bulk metallic glass in form of as-cast rods.Design/methodology/approach: The investigations on the ternary Ca-Mg-Zn glassy rods were conducted by using X-ray diffraction (XRD, scanning electron microscopy (SEM which energy dispersive X-ray analysis (EDS.Findings: The X-ray diffraction investigations have revealed that the studied as-cast rod was amorphous. The fractures of studied alloy could be classified as mixed fracture with indicated “river” and “smooth” fractures. Both type of the fracture surfaces consist of weakly formed “river” and “shell” patterns and “smooth” regions. The “river” patterns are characteristic for metallic glassy alloys.Practical implications: The studied Ca-based bulk metallic glasses is a relatively new group of material. Ca-based bulk metallic glasses are applied for many applications in different elements. Ca-based bulk metallic glasses have many unique properties such as low density (~2.0 g/cm3, low Youn g’s modulus ( ~20 to 30 GPa. The elastic modulus of Ca-b ased BMGs is comparable to that of hum an bone s, and Ca, Mg, and Zn are biocompatible. These features make the Ca-Mg-Zn–based alloys attractive for use in biomedical applications.Originality/value: Fabrication of amorphous alloy in the form of rod ternary Ca-Mg-Zn alloy by pressure die casting method.

  19. Influence of bulk pre-straining on the size effect in nickel compression pillars

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, A.S., E-mail: Andreas.schneider@inm-gmbh.de [INM-Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbruecken (Germany); Kiener, D. [University of Leoben, Department of Materials Physics, Jahnstr. 12, 8700 Leoben (Austria); Yakacki, C.M. [Department of Mechanical Engineering, University of Colorado Denver, Denver 80217 (United States); Maier, H.J. [University of Paderborn, Lehrstuhl fuer Werkstoffkunde (Materials Science), 33098 Paderborn (Germany); Gruber, P.A. [Karlsruhe Institute of Technology, Institute for Applied Materials, Kaiserstr. 12, 76131 Karlsruhe (Germany); Tamura, N.; Kunz, M. [Advanced Light Source (ALS), Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Minor, A.M. [Department of Materials Science and Engineering, University of California, Berkeley, and National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Frick, C.P. [University of Wyoming, Mechanical Engineering Department, 1000 East University Avenue, Laramie, WY 82071 (United States)

    2013-01-01

    Micro-compression tests were performed on pre-strained nickel (Ni) single crystals in order to investigate the influence of the initial dislocation arrangement on the size dependence of small-scale metal structures. A bulk Ni sample was grown using the Czochralski method and sectioned into four compression samples, which were then pre-strained to nominal strains of 5, 10, 15 and 20%. Bulk samples were then characterized using transmission electron microscopy (TEM), micro-Laue diffraction, and electron backscatter diffraction. TEM results show that a dislocation cell structure was present for all deformed samples, and Laue diffraction demonstrated that the internal strain increased with increased amount of pre-straining. Small-scale pillars with diameters from 200 nm to 5 {mu}m were focused ion beam (FIB) machined from each of the four deformed bulk samples and further compressed via a nanoindenter equipped with a flat diamond punch. Results demonstrate that bulk pre-straining inhibits the sample size effect. For heavily pre-strained bulk samples, the deformation history does not affect the stress-strain behavior, as the pillars demonstrated elevated strength and rather low strain hardening over the whole investigated size range. In situ TEM and micro-Laue diffraction measurements of pillars confirmed little change in dislocation density during pillar compression. Thus, the dislocation cell walls created by heavy bulk pre-straining become the relevant internal material structure controlling the mechanical properties, dominating the sample size effect observed in the low dislocation density regime.

  20. Density heterogeneity of the cratonic lithosphere

    DEFF Research Database (Denmark)

    Cherepanova, Yulia; Artemieva, Irina

    2015-01-01

    the base of the CBL is at a 180 km depth. The uncertainty of density model is lithospheric mantle with a strong...... variations in the isopycnic state, correlated with mantle depletion and best achieved for the Anabar Shield region and other intracratonic domains with a strongly depleted mantle. A comparison of synthetic Mg# for the bulk lithospheric mantle calculated from density with Mg# from petrological studies...

  1. Stability of bulk metallic glass structure

    Energy Technology Data Exchange (ETDEWEB)

    Jain, H.; Williams, D.B.

    2003-06-18

    The fundamental origins of the stability of the (Pd-Ni){sub 80}P{sub 20} bulk metallic glasses (BMGs), a prototype for a whole class of BMG formers, were explored. While much of the properties of their BMGs have been characterized, their glass-stability have not been explained in terms of the atomic and electronic structure. The local structure around all three constituent atoms was obtained, in a complementary way, using extended X-ray absorption fine structure (EXAFS), to probe the nearest neighbor environment of the metals, and extended energy loss fine structure (EXELFS), to investigate the environment around P. The occupied electronic structure was investigated using X-ray photoelectron spectroscopy (XPS). The (Pd-Ni){sub 80}P{sub 20} BMGs receive their stability from cumulative, and interrelated, effects of both atomic and electronic origin. The stability of the (Pd-Ni){sub 80}P{sub 20} BMGs can be explained in terms of the stability of Pd{sub 60}Ni{sub 20}P{sub 20} and Pd{sub 30}Ni{sub 50}P{sub 20}, glasses at the end of BMG formation. The atomic structure in these alloys is very similar to those of the binary phosphide crystals near x=0 and x=80, which are trigonal prisms of Pd or Ni atoms surrounding P atoms. Such structures are known to exist in dense, randomly-packed systems. The structure of the best glass former in this series, Pd{sub 40}Ni{sub 40}P{sub 20} is further described by a weighted average of those of Pd{sub 30}Ni{sub 50}P{sub 20} and Pd{sub 60}Ni{sub 20}P{sub 20}. Bonding states present only in the ternary alloys were found and point to a further stabilization of the system through a negative heat of mixing between Pd and Ni atoms. The Nagel and Tauc criterion, correlating a decrease in the density of states at the Fermi level with an increase in the glass stability, was consistent with greater stability of the Pd{sub x}Ni{sub (80-x)}P{sub 20} glasses with respect to the binary alloys of P. A valence electron concentration of 1.8 e/a, which

  2. Anisotropy Effect on Levitation Performance of Bulk High-Tc Superconductors Above a Permanent Magnet Guideway

    Science.gov (United States)

    Zheng, Jun; Liao, Xinglin; Jing, Hailian; Lin, Qunxu; Ma, Guangtong; Yen, Fei; Wang, Suyu; Wang, Jiasu

    The anisotropy properties of bulk high-temperature superconductors (HTSCs) are taken into consideration for the application of high-temperature superconducting (HTS) Maglev systems, which are especially based on the different flux-trapping capabilities as well as critical current density, Jc, values between the growth section boundary (GSB) and the growth sections (GS) in bulk superconductors. By adjusting the angle between the GSB of bulk HTSCs and the strongest magnetic field position of a permanent magnet guideway (PMG), the levitation force and its relaxation processes are compared at different field-cooling conditions. Experimental results show that the levitation capability and the suppression of levitation force decay can be enhanced by optimizing the GS/GSB alignment of every bulk HTSC above the PMG. Meanwhile, our conclusions may provide references to other HTS maglev systems with small levitation gaps, i.e., superconducting magnetic bearings.

  3. Bulk viscosity for pion and nucleon thermal fluctuation in the hadron resonance gas model

    CERN Document Server

    Ghosh, Sabyasachi; Mohanty, Bedangdas

    2016-01-01

    We have calculated microscopically bulk viscosity of hadronic matter, where equilibrium thermodynamics for all hadrons in medium are described by Hadron Resonance Gas (HRG) model. Considering pions and nucleons as abundant medium constituents, we have calculated their thermal widths, which inversely control the strength of bulk viscosities for respective components and represent their in-medium scattering probabilities with other mesonic and baryonic resonances, present in the medium. Our calculations show that bulk viscosity increases with both temperature and baryon chemical potential, whereas viscosity to entropy density ratio decreases with temperature and with baryon chemical potential, the ratio increases first and then decreases. The decreasing nature of the ratio with temperature is observed in most of the earlier investigations with few exceptions. We find that the temperature dependence of bulk viscosity crucially depends on the structure of the relaxation time. Along the chemical freeze-out line in...

  4. Transport Coefficients of Bulk Viscous Pressure in the 14-moment approximation

    CERN Document Server

    Denicol, G S; Gale, C

    2014-01-01

    We compute the transport coefficients that appear in the fluid-dynamical equations for the bulk viscous pressure and shear-stress tensor using the 14-moment approximation in the limit of small, but finite, masses. In this limit, we are able to express all these coefficients in terms of known thermodynamic quantities, such as the thermodynamic pressure, energy density, and the velocity of sound. We explicitly demonstrate that the ratio of bulk viscosity to bulk relaxation time behaves very differently, as a function of temperature, than the ratio of shear viscosity to shear relaxation time. We further explicitly compute, for the first time, the transport coefficients that couple the bulk viscous pressure to the shear-stress tensor and vice versa. The coefficient that couples bulk viscous pressure to shear-stress tensor is found to be orders of magnitude larger than the bulk viscosity itself, suggesting that bulk viscous pressure production owes more to this coupling than to the expansion rate of the system.

  5. Transport coefficients of bulk viscous pressure in the 14-moment approximation

    Science.gov (United States)

    Denicol, G. S.; Jeon, S.; Gale, C.

    2014-08-01

    We compute the transport coefficients that appear in the fluid-dynamical equations for the bulk viscous pressure and shear-stress tensor using the 14-moment approximation in the limit of small, but finite, masses. In this limit, we are able to express all these coefficients in terms of known thermodynamic quantities, such as the thermodynamic pressure, energy density, and the velocity of sound. We explicitly demonstrate that the ratio of bulk viscosity to bulk relaxation time behaves very differently, as a function of temperature, than the ratio of shear viscosity to shear relaxation time. We further explicitly compute, for the first time, the transport coefficients that couple the bulk viscous pressure to the shear-stress tensor and vice versa. The coefficient that couples bulk viscous pressure to shear-stress tensor is found to be orders of magnitude larger than the bulk viscosity itself, suggesting that bulk viscous pressure production owes more to this coupling than to the expansion rate of the system.

  6. Bulk characterization of pharmaceutical powders by low-pressure compression.

    Science.gov (United States)

    Sørensen, Arne Hagsten; Sonnergaard, Jørn Møller; Hovgaard, Lars

    2005-01-01

    Low-pressure compression of pharmaceutical powders using small amounts of sample (50 mg) was evaluated as an alternative to traditional bulk powder characterization by tapping volumetry. Material parameters were extrapolated directly from the compression data and by fitting with the Walker, the Kawakita, and the Log-Exp compression models. The compression-derived material parameters were compared to the poured and tapped density and the Compressibility Index determined by tapping. The repeatability of the compression-derived parameters was generally high, supporting their potential for characterization purposes. Significant correlation was demonstrated between several of the compression and tapping-derived parameters. The discriminative power of the low-pressure compression test was discussed using the compressed density at 0.2 MPa, correlated with the tapped density, and the relative Walker coefficient, correlated with the Compressibility Index, as examples. The compressed density at 0.2 MPa and the relative Walker coefficient demonstrated excellent discriminative power, superior to the discriminative power of the correlated tapping derived parameters. The low-pressure compression test was concluded to provide a cost-effective and sensitive alternative to traditional tapping volumetry.

  7. Development of fabrication technique of bulk high superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Gye Won; Kim, Chang Joong; Kim, Ki Baik; Lee, Ho Jin; Lee, Hee Gyoun; Kwon, Sun Chil

    1997-05-01

    In order to realize the commercial application of HTSC materials, it is necessary to develop the fabrication process of high Tc oxide superconductor materials with desired shape and for practical application and high critical current density as well as good mechanical strength which critical current density as well as good mechanical strength which can withstand high lorenz force generated at high magnetic field. Much studies have been concentrated to develop the fabrication technique for high critical current density but still there are a lot of gap which should be overcome for large scale application of HTSC materials at liquid nitrogen temperature. Recently some new fabrication techniques have been developed for YBCO bulk superconductor with high mechanical strength and critical current density. In this project, plastic extrusion and melt process techniques were studied. The components materials for the current lead and the flywheel application were fabricated and their characteristics were investigated from the view point of microstructure and phase formation during heat treatment process. (author). 64 refs., 59 figs.

  8. Development of fabrication technique of bulk high superconductor

    International Nuclear Information System (INIS)

    In order to realize the commercial application of HTSC materials, it is necessary to develop the fabrication process of high Tc oxide superconductor materials with desired shape and for practical application and high critical current density as well as good mechanical strength which critical current density as well as good mechanical strength which can withstand high lorenz force generated at high magnetic field. Much studies have been concentrated to develop the fabrication technique for high critical current density but still there are a lot of gap which should be overcome for large scale application of HTSC materials at liquid nitrogen temperature. Recently some new fabrication techniques have been developed for YBCO bulk superconductor with high mechanical strength and critical current density. In this project, plastic extrusion and melt process techniques were studied. The components materials for the current lead and the flywheel application were fabricated and their characteristics were investigated from the view point of microstructure and phase formation during heat treatment process. (author). 64 refs., 59 figs

  9. Into the Bulk: A Covariant Approach

    CERN Document Server

    Engelhardt, Netta

    2016-01-01

    I propose a general, covariant way of defining when one region is "deeper in the bulk" than another. This definition is formulated outside of an event horizon (or in the absence thereof) in generic geometries; it may be applied to both points and surfaces, and may be used to compare the depth of bulk points or surfaces relative to a particular boundary subregion or relative to the entire boundary. Using the recently proposed "lightcone cut" formalism, the comparative depth between two bulk points can be determined from the singularity structure of Lorentzian correlators in the dual field theory. I prove that, by this definition, causal wedges of progressively larger regions probe monotonically deeper in the bulk. The definition furthermore matches expectations in pure AdS and in static AdS black holes with isotropic spatial slices, where a well-defined holographic coordinate exists. In terms of holographic RG flow, this new definition of bulk depth makes contact with coarse-graining over both large distances ...

  10. Surface and bulk dissolution properties, and selectivity of DNA-linked nanoparticle assemblies

    NARCIS (Netherlands)

    Lukatsky, D.B.; Frenkel, D.

    2005-01-01

    Using a simple mean-field model, we analyze the surface and bulk dissolution properties of DNA-linked nanoparticle assemblies. We find that the dissolution temperature and the sharpness of the dissolution profiles increase with the grafting density of the single-stranded DNA "probes" on the surface

  11. Revised Thickness of the Lunar Crust from GRAIL Data: Implications for Lunar Bulk Composition

    Science.gov (United States)

    Taylor, G. Jeffrey; Wieczorek, Mark A.; Neumann, Gregory A.; Nimmo, Francis; Kiefer, Walter S.; Melosh, H. Jay; Phillips, Roger J.; Solomon, Sean C.; Andrews-Hanna, Jeffrey C.; Asmar, Sami W.; Konopliv, Alexander S.; Lemoine, Frank G.; Smith, David E.; Watkins, Michael W.; Williams, James G.; Zuber, Maria T.

    2013-01-01

    High-resolution gravity data from GRAIL have yielded new estimates of the bulk density and thickness of the lunar crust. The bulk density of the highlands crust is 2550 kg m-3. From a comparison with crustal composition measured remotely, this density implies a mean porosity of 12%. With this bulk density and constraints from the Apollo seismic experiment, the average global crustal thickness is found to lie between 34 and 43 km, a value 10 to 20 km less than several previous estimates. Crustal thickness is a central parameter in estimating bulk lunar composition. Estimates of the concentrations of refractory elements in the Moon from heat flow, remote sensing and sample data, and geophysical data fall into two categories: those with refractory element abundances enriched by 50% or more relative to Earth, and those with abundances the same as Earth. Settling this issue has implications for processes operating during lunar formation. The crustal thickness resulting from analysis of GRAIL data is less than several previous estimates. We show here that a refractory-enriched Moon is not required

  12. Universality principle and the development of classical density functional theory

    Institute of Scientific and Technical Information of China (English)

    周世琦; 张晓琪

    2002-01-01

    The universality principle of the free energy density functional and the ‘test particle' trick by Percus are combined to construct the approximate free energy density functional or its functional derivative. Information about the bulk fluid ralial distribution function is integrated into the density functional approximation directly for the first time in the present methodology. The physical foundation of the present methodology also applies to the quantum density functional theory.

  13. Thermodynamic regularities in compressed liquids: II. The reduced bulk modulus

    International Nuclear Information System (INIS)

    In a previous work, we analysed some regularities found in the behaviour of the thermal expansion coefficient, αp, in compressed liquids. We confirmed that a given liquid presents a characteristic pressure range in which the condition (∂αp/∂T)p=0 is fulfilled within a narrow range of reduced densities. We also found that the density at which the condition (∂αp/∂T)p=0 is satisfied, ρα, decreases with temperature, a key feature not described before. Earlier studies by other authors suggested that similar regularities are expected for the reduced bulk modulus, B. We present here a detailed analysis of the temperature and density dependence of B from existing experimental results at high pressures. Several liquids have been analysed: argon, krypton, xenon, ethylene, tetrafluoromethane, trifluoromethane, carbon dioxide, carbon disulfide, n-butane, n-hexane, toluene, ethanol, 1-hexanol, m-cresol, and quinoline. We locate that the density ρB that fulfils the condition (∂B/∂T)ρ=0 occurs at a particular region of the phase diagram, between 3.4 and 2.4 times the critical density of each liquid. Interestingly, the previously found density ρα is close to ρB, in a similar region of the reduced phase diagram. However, we note that ρB typically decreases to a lesser extent with temperature than ρα. In addition, we have found that ρB(T) behaves in a parallel fashion for the different liquids, showing larger values of ρB as the complexity of the molecules increases. These findings provide a strong basis for developing general equation of state models to describe the behaviour of liquids in the high-pressure regime

  14. Molecular density functional theory of water including density-polarization coupling

    CERN Document Server

    Jeanmairet, Guillaume; Levesque, Maximilien; Borgis, Daniel

    2016-01-01

    We present a three-dimensional molecular density functional theory (MDFT) of water derived from first-principles that relies on the particle's density and multipolar polarization density and includes the density-polarization coupling. This brings two main benefits: ($i$) a scalar density and a vectorial multipolar polarization density fields are much more tractable and give more physical insight than the full position and orientation densities, and ($ii$) it includes the full density-polarization coupling of water, that is known to be non-vanishing but has never been taken into account. Furthermore, the theory requires only the partial charge distribution of a water molecule and three measurable bulk properties, namely the structure factor and the Fourier components of the longitudinal and transverse dielectric susceptibilities.

  15. Orchestrating Bulk Data Movement in Grid Environments

    Energy Technology Data Exchange (ETDEWEB)

    Vazhkudai, SS

    2005-01-25

    Data Grids provide a convenient environment for researchers to manage and access massively distributed bulk data by addressing several system and transfer challenges inherent to these environments. This work addresses issues involved in the efficient selection and access of replicated data in Grid environments in the context of the Globus Toolkit{trademark}, building middleware that (1) selects datasets in highly replicated environments, enabling efficient scheduling of data transfer requests; (2) predicts transfer times of bulk wide-area data transfers using extensive statistical analysis; and (3) co-allocates bulk data transfer requests, enabling parallel downloads from mirrored sites. These efforts have demonstrated a decentralized data scheduling architecture, a set of forecasting tools that predict bandwidth availability within 15% error and co-allocation architecture, and heuristics that expedites data downloads by up to 2 times.

  16. A diphoton resonance from bulk RS

    Science.gov (United States)

    Csáki, Csaba; Randall, Lisa

    2016-07-01

    Recent LHC data hinted at a 750 GeV mass resonance that decays into two photons. A significant feature of this resonance is that its decays to any other Standard Model particles would be too low to be detected so far. Such a state has a compelling explanation in terms of a scalar or a pseudoscalar that is strongly coupled to vector states charged under the Standard Model gauge groups. Such a scenario is readily accommodated in bulk RS with a scalar localized in the bulk away from but close to the Higgs. Turning this around, we argue that a good way to find the elusive bulk RS model might be the search for a resonance with prominent couplings to gauge bosons.

  17. Bulk fields from the boundary OPE

    CERN Document Server

    Guica, Monica

    2016-01-01

    Previous work has established an equality between the geodesic integral of a free bulk field in AdS and the contribution of the conformal descendants of its dual CFT primary operator to the OPE of two other operators inserted at the endpoints of the geodesic. Working in the context of AdS$_3$/CFT$_2$, we extend this relation to include all $1/N$ corrections to the bulk field obtained by dressing it with i) a $U(1)$ current and ii) the CFT stress tensor, and argue it equals the contribution of the Ka\\v{c}-Moody/the Virasoro block to the respective boundary OPE. This equality holds for a particular framing of the bulk field to the boundary that involves a split Wilson line.

  18. Multiphase composites with extremal bulk modulus

    DEFF Research Database (Denmark)

    Gibiansky, L. V.; Sigmund, Ole

    2000-01-01

    This paper is devoted to the analytical and numerical study of isotropic elastic composites made of three or more isotropic phases. The ranges of their effective bulk and shear moduli are restricted by the Hashin-Shtrikman-Walpole (HSW) bounds. For two-phase composites, these bounds are attainable......, that is, there exist composites with extreme bulk and shear moduli. For multiphase composites, they may or may not be attainable depending on phase moduli and volume fractions. Sufficient conditions of attainability of the bounds and various previously known and new types of optimal composites...... are described. Most of our new results are related to the two-dimensional problem. A numerical topology optimization procedure that solves the inverse homogenization problem is adopted and used to look for two-dimensional three-phase composites with a maximal effective bulk modulus. For the combination...

  19. A Diphoton Resonance from Bulk RS

    CERN Document Server

    Csaki, Csaba

    2016-01-01

    Recent LHC data hints at a 750 GeV mass resonance that decays into two photons. A significant feature of this resonance is that its decays to Higges and to any other Standard Model particles are so far too low to be detected. Such a state has a compelling explanation in terms of a scalar or a pseudoscalar that is strongly coupled to vector states charged under the Standard Model gauge groups. We argue that if the state is a scalar, some form of sequestering is likely to be necessary to naturally explain the suppressed scalar-Higgs interactions. Such a scenario is readily accommodated in bulk RS with a scalar localized in the bulk away from the Higgs. Turning this around, we argue that a good way to find the elusive bulk RS model might be the search for a resonance with prominent couplings to gauge bosons.

  20. Bulk Comptonization by Turbulence in Accretion Disks

    CERN Document Server

    Kaufman, J

    2016-01-01

    Radiation pressure dominated accretion discs around compact objects may have turbulent velocities that greatly exceed the electron thermal velocities within the disc. Bulk Comptonization by the turbulence may therefore dominate over thermal Comptonization in determining the emergent spectrum. Bulk Comptonization by divergenceless turbulence is due to radiation viscous dissipation only. It can be treated as thermal Comptonization by solving the Kompaneets equation with an equivalent "wave" temperature, which is a weighted sum over the power present at each scale in the turbulent cascade. Bulk Comptonization by turbulence with non-zero divergence is due to both pressure work and radiation viscous dissipation. Pressure work has negligible effect on photon spectra in the limit of optically thin turbulence, and in this limit radiation viscous dissipation alone can be treated as thermal Comptonization with a temperature equivalent to the full turbulent power. In the limit of extremely optically thick turbulence, ra...

  1. Using X-ray Imaging Techniques to Determine Density of Foods

    OpenAIRE

    Kelkar, Shivangi Mohan

    2013-01-01

    Density depends on the experimental technique and structural properties of food. True, apparent and bulk are different types of densities. For porous foods such as baked food products and complex food systems, accurate measurement of density is challenging. Empirical correlations dependent on composition and temperature exist to calculate true density. Thus if composition and apparent density are known, porosity can be calculated, porosity = [1 - (apparent density/ true density)]. Various non...

  2. A trapped field of >3 T in bulk MgB2 fabricated by uniaxial hot pressing

    International Nuclear Information System (INIS)

    A trapped field of over 3 T has been measured at 17.5 K in a magnetized stack of two disc-shaped bulk MgB2 superconductors of diameter 25 mm and thickness 5.4 mm. The bulk MgB2 samples were fabricated by uniaxial hot pressing, which is a readily scalable, industrial technique, to 91% of their maximum theoretical density. The macroscopic critical current density derived from the trapped field data using the Biot–Savart law is consistent with the measured local critical current density. From this we conclude that critical current density, and therefore trapped field performance, is limited by the flux pinning available in MgB2, rather than by lack of connectivity. This suggests strongly that both increasing sample size and enhancing pinning through doping will allow further increases in trapped field performance of bulk MgB2. (rapid communication)

  3. Radiation-hardened bulk CMOS technology

    International Nuclear Information System (INIS)

    The evolutionary development of a radiation-hardened bulk CMOS technology is reviewed. The metal gate hardened CMOS status is summarized, including both radiation and reliability data. The development of a radiation-hardened bulk silicon gate process which was successfully implemented to a commercial microprocessor family and applied to a new, radiation-hardened, LSI standard cell family is also discussed. The cell family is reviewed and preliminary characterization data is presented. Finally, a brief comparison of the various radiation-hardened technologies with regard to performance, reliability, and availability is made

  4. Remedial investigations for quarry bulk wastes

    International Nuclear Information System (INIS)

    The US Department of Energy proposes, as a separate operable unit of the Weldon Spring Site Remedial Action Project, to remove contaminated bulk wastes from the Weldon Spring quarry and transport them approximately four miles to the chemical plant portion of the raffinate pits and chemical plant area. The wastes will be held in temporary storage prior to the record of decision for the overall remedial action. The decision on the ultimate disposal of these bulk wastes will be included as part of the decision for management of the waste materials resulting from remedial action activities at the raffinate pits and chemical plant area. 86 refs., 71 figs., 83 tabs

  5. Bulk Entropy in Loop Quantum Gravity

    OpenAIRE

    Livine, Etera R; Terno, Daniel R.

    2007-01-01

    In the framework of loop quantum gravity (LQG), having quantum black holes in mind, we generalize the previous boundary state counting (gr-qc/0508085) to a full bulk state counting. After a suitable gauge fixing we are able to compute the bulk entropy of a bounded region (the "black hole") with fixed boundary. This allows us to study the relationship between the entropy and the boundary area in details and we identify a holographic regime of LQG where the leading order of the entropy scales w...

  6. Bulk Entropy in Loop Quantum Gravity

    CERN Document Server

    Livine, Etera R

    2007-01-01

    In the framework of loop quantum gravity (LQG), having quantum black holes in mind, we generalize the previous boundary state counting (gr-qc/0508085) to a full bulk state counting. After a suitable gauge fixing we are able to compute the bulk entropy of a bounded region (the "black hole") with fixed boundary. This allows us to study the relationship between the entropy and the boundary area in details and we identify a holographic regime of LQG where the leading order of the entropy scales with the area. We show that in this regime we can fine tune the factor between entropy and area without changing the Immirzi parameter.

  7. Thermal relics in cosmology with bulk viscosity

    International Nuclear Information System (INIS)

    In this paper we discuss some consequences of cosmological models in which the primordial cosmic matter is described by a relativistic imperfect fluid. The latter takes into account the dissipative effects (bulk viscosity) arising from different cooling rates of the fluid components in the expanding Universe. We discuss, in particular, the effects of the bulk viscosity on Big Bang Nucleosynthesis and on the thermal relic abundance of particles, looking at recent results of PAMELA experiment. The latter has determined an anomalous excess of positron events, which cannot be explained by conventional cosmology and particle physics. (orig.)

  8. Synthesis of Bulk Superconducting Magnesium Diboride

    Directory of Open Access Journals (Sweden)

    Margie Olbinado

    2002-06-01

    Full Text Available Bulk polycrystalline superconducting magnesium diboride, MgB2, samples were successfully prepared via a one-step sintering program at 750°C, in pre Argon with a pressure of 1atm. Both electrical resistivity and magnetic susceptibility measurements confirmed the superconductivity of the material at 39K, with a transition width of 5K. The polycrystalline nature, granular morphology, and composition of the sintered bulk material were confirmed using X-ray diffractometry (XRD, scanning electron microscopy (SEM, and energy dispersive X-ray analysis (EDX.

  9. Nuclear energy density optimization: Shell structure

    CERN Document Server

    Kortelainen, M; Nazarewicz, W; Olsen, E; Reinhard, P -G; Sarich, J; Schunck, N; Wild, S M; Davesne, D; Erler, J; Pastore, A

    2013-01-01

    Nuclear density functional theory is the only microscopical theory that can be applied throughout the entire nuclear landscape. Its key ingredient is the energy density functional. In this work, we propose a new parameterization UNEDF2 of the local Skyrme energy density functional. The functional optimization is carried out using the POUNDerS optimization algorithm within the framework of the Skyrme Hartree-Fock-Bogoliubov theory. Compared to the previous parameterization UNEDF1, restrictions on the tensor term of the energy density have been lifted, yielding the most general form of the Skyrme energy density functional up to second order in derivatives of the one-body local density. In order to impose constraints on all the parameters of the functional, selected data on single-particle splittings in spherical doubly-magic nuclei have been included into the experimental dataset. The agreement with both bulk and spectroscopic nuclear properties achieved by the resulting UNEDF2 parameterization is comparable wi...

  10. Experimental investigation and mechanistic modelling of dilute bubbly bulk boiling

    International Nuclear Information System (INIS)

    During evaporation the geometric shape of the vapour is not described using thermodynamics. In bubbly flows the bubble shape is considered spheric with small diameters and changing into various shapes upon growth. The heat and mass transfer happens at the interfacial area. The forces acting on the bubbles depend on the bubble diameter and shape. In this work the prediction of the bubble diameter and/or bubble number density in bulk boiling was considered outside the vicinity of the heat input area. Thus the boiling effects that happened inside the nearly saturated bulk were under investigation. This situation is relevant for nuclear safety analysis concerning a stagnant coolant in the spent fuel pool. In this research project a new experimental set-up to investigate was built. The experimental set-up consists of an instrumented, partly transparent, high and slender boiling container for visual observation. The direct visual observation of the boiling phenomena is necessary for the identification of basic mechanisms, which should be incorporated in the simulation model. The boiling process has been recorded by means of video images and subsequently was evaluated by digital image processing methods, and by that data concerning the characteristics of the boiling process were generated for the model development and validation. Mechanistic modelling is based on the derivation of relevant mechanisms concluded from observation, which is in line with physical knowledge. In this context two mechanisms were identified; the growth/-shrink mechanism (GSM) of the vapour bubbles and sudden increases of the bubble number density. The GSM was implemented into the CFD-Code ANSYS-CFX using the CFX Expression Language (CEL) by calculation of the internal bubble pressure using the Young-Laplace-Equation. This way a hysteresis is realised as smaller bubbles have an increased internal pressure. The sudden increases of the bubble number density are explainable by liquid super

  11. Record critical current densities in IG processed bulk YBa{sub 2}Cu{sub 3}O{sub y} fabricated using ball-milled Y{sub 2}Ba{sub 1}Cu{sub 1}O{sub 5} phase

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, Miryala; Kenta, Nakazato; Murakami, Masato [Department of Materials Science and Engineering, Superconducting Materials Laboratory, Shibaura Institute of Technology, Tokyo (Japan); Zeng, XianLin; Koblischka, Michael R. [Institute of Experimental Physics, Saarland University, Saarbruecken (Germany); Diko, Pavel [Institute of Experimental Physics, Material Physics Laboratory, Slovak Academy of Sciences, Kosice (Slovakia)

    2016-02-15

    The infiltration-growth (IG) technique enables the uniform and controllable Y{sub 2}BaCuO{sub 5} (Y211) secondary phase particles formation within the YBa{sub 2}Cu{sub 3}O{sub y} (Y123) matrix. Recent results clarified that the flux pinning performance of the Y123 material was dramatically improved by optimizing the processing conditions during the IG process. In this paper, we adapted the IG technique and produced several samples with addition of nanometer-sized Y211 secondary phase particles, which were produced by a ball milling technique. We found that the performance of the IG processed Y123 material dramatically improved in the low field region for a ball milling time of 12 h as compared to the samples without a ball milling step. Magnetization measurements showed a sharp superconducting transition with an onset T{sub c} at around 92 K. The critical current density (J{sub c}) at 77 K and zero field was determined to be 224 022 Acm{sup -2}, which is higher than the not ball-milled sample. Furthermore, microstructural observations exhibited a uniform microstructure with homogenous distribution of nanosized Y-211 inclusions within the Y-123 matrix. The improved performance of the Y-123 material can be understood in terms of fine distribution of the secondary phases. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. THE OPTIMIZATION OF PLUSH YARNS BULKING PROCESS

    Directory of Open Access Journals (Sweden)

    VINEREANU Adam

    2014-05-01

    Full Text Available This paper presents the experiments that were conducted on the installation of continuous bulking and thermofixing “SUPERBA” type TVP-2S for optimization of the plush yarns bulking process. There were considered plush yarns Nm 6.5/2, made of the fibrous blend of 50% indigenous wool sort 41 and 50% PES. In the first stage, it performs a thermal treatment with a turboprevaporizer at a temperature lower than thermofixing temperature, at atmospheric pressure, such that the plush yarns - deposed in a freely state on a belt conveyor - are uniformly bulking and contracting. It was followed the mathematical modeling procedure, working with a factorial program, rotatable central composite type, and two independent variables. After analyzing the parameters that have a direct influence on the bulking degree, there were selected the pre-vaporization temperature (coded x1,oC and the velocity of belt inside pre-vaporizer (coded x 2, m/min. As for the dependent variable, it was chosen the plush yarn diameter (coded y, mm. There were found the coordinates of the optimal point, and then this pair of values was verified in practice. These coordinates are: x1optim= 90oC and x 2optim= 6.5 m/min. The conclusion is that the goal was accomplished: it was obtained a good cover degree f or double-plush carpets by reducing the number of tufts per unit surface.

  13. A Stereoscopic Look into the Bulk

    CERN Document Server

    Czech, Bartlomiej; McCandlish, Samuel; Mosk, Benjamin; Sully, James

    2016-01-01

    We present the foundation for a holographic dictionary with depth perception. The dictionary consists of natural CFT operators whose duals are simple, diffeomorphism-invariant bulk operators. The CFT operators of interest are the "OPE blocks," contributions to the OPE from a single conformal family. In holographic theories, we show that the OPE blocks are dual at leading order in 1/N to integrals of effective bulk fields along geodesics or homogeneous minimal surfaces in anti-de Sitter space. One widely studied example of an OPE block is the modular Hamiltonian, which is dual to the fluctuation in the area of a minimal surface. Thus, our operators pave the way for generalizing the Ryu-Takayanagi relation to other bulk fields. Although the OPE blocks are non-local operators in the CFT, they admit a simple geometric description as fields in kinematic space--the space of pairs of CFT points. We develop the tools for constructing local bulk operators in terms of these non-local objects. The OPE blocks also allow ...

  14. Bulk metamaterials: Design, fabrication and characterization

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Alabastri, Alessandro;

    2009-01-01

    Bulk metamaterials claim a lot of attention worldwide. We report about our activity and advances in design, fabrication and characterization of metal-dielectric composites with three-dimensional lattices. The nomenclature of designs exhibiting negative index behaviour in the near infrared includes...

  15. Realistic anomaly mediation with bulk gauge fields

    International Nuclear Information System (INIS)

    We present a simple general framework for realistic models of supersymmetry breaking driven by anomaly mediation. We consider a 5-dimensional 'brane universe' where the visible and hidden sectors are localized on different branes, and the standard model gauge bosons propagate in the bulk. In this framework there can be charged scalar messengers that have contact interactions with the hidden sector, either localized in the hidden sector or in the bulk. These scalars obtain soft masses that feed into visible sector scalar masses at two loop order via bulk gauge interactions. This contribution is automatically flavor-blind, and can be naturally positive. If the messengers are in the bulk this contribution is automatically the same order of magnitude as the anomaly mediated contribution, independent of the brane spacing. If the messengers are localized to a brane the two effects are of the same order for relatively small brane spacings. The gaugino masses and A terms are determined completely by anomaly mediation. In order for anomaly mediation to dominate over radion mediation the radion must be is stabilized in a manner that preserves supersymmetry, with supergravity effects included. We show that this occurs in simple models. We also show that the mu problem can be solved by the vacuum expectation value of a singlet in this framework. (author)

  16. Longitudinal bulk a coustic mass sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Teva, Jordi; Boisen, Anja;

    2009-01-01

    Design, fabrication and characterization, in terms of mass sensitivity, is presented for a polycrystalline silicon longitudinal bulk acoustic cantilever. The device is operated in air at 51 MHz, resulting in a mass sensitivity of 100 HZ/fg (1 fg = 10{su−15 g). The initial characterization...

  17. Integration of bulk piezoelectric materials into microsystems

    Science.gov (United States)

    Aktakka, Ethem Erkan

    Bulk piezoelectric ceramics, compared to deposited piezoelectric thin-films, provide greater electromechanical coupling and charge capacity, which are highly desirable in many MEMS applications. In this thesis, a technology platform is developed for wafer-level integration of bulk piezoelectric substrates on silicon, with a final film thickness of 5-100microm. The characterized processes include reliable low-temperature (200°C) AuIn diffusion bonding and parylene bonding of bulk-PZT on silicon, wafer-level lapping of bulk-PZT with high-uniformity (+/-0.5microm), and low-damage micro-machining of PZT films via dicing-saw patterning, laser ablation, and wet-etching. Preservation of ferroelectric and piezoelectric properties is confirmed with hysteresis and piezo-response measurements. The introduced technology offers higher material quality and unique advantages in fabrication flexibility over existing piezoelectric film deposition methods. In order to confirm the preserved bulk properties in the final film, diaphragm and cantilever beam actuators operating in the transverse-mode are designed, fabricated and tested. The diaphragm structure and electrode shapes/sizes are optimized for maximum deflection through finite-element simulations. During tests of fabricated devices, greater than 12microm PP displacement is obtained by actuation of a 1mm2 diaphragm at 111kHz with management IC, which incorporates a supply-independent bias circuitry, an active diode for low-dropout rectification, a bias-flip system for higher efficiency, and a trickle battery charger. The overall system does not require a pre-charged battery, and has power consumption of sleep-mode (simulated). Under lg vibration at 155Hz, a 70mF ultra-capacitor is charged from OV to 1.85V in 50 minutes.

  18. Bulk sulfur (S) deposition in China

    Science.gov (United States)

    Liu, Lei; Zhang, Xiuying; Wang, Shanqian; Zhang, Wuting; Lu, Xuehe

    2016-06-01

    A systematic dataset of an observation network on a national scale has been organized to investigate the spatial distribution of bulk sulfur (S) deposition (Sdep) throughout China during 2000-2013, representing by far the most detailed data set to track the bulk sulfur deposition throughout China since 2000. Such a dataset is needed for ecosystem studies and for developing emission control policies. Bulk Sdep values showed great variations, ranging from 2.17 to 70.55 kg ha-1 y-1, with an average of 22.99 kg ha-1 y-1. The average rate of bulk Sdep located in East Coastal region (35.97 kg ha-1 y-1), Middle Yangtze region (57.90 kg ha-1 y-1), Middle Yellow River region (23.42 kg ha-1 y-1), North Coastal region (42.19 kg ha-1 y-1), Northeast region (34.28 kg ha-1 y-1), South Coastal region (36.97 kg S ha-1 y-1), Southwest region (33.85 kg ha-1 y-1) was 4.50, 7.24, 2.93, 5.28, 4.29, 4.63 and 4.24 times than that in Northwest region (7.99 kg ha-1 y-1). Bulk Sdep over China was mainly from fossil fuel combustion (76.96%), biomass burning (7.64%), crust (6.22%), aged sea salt (5.48%) and agriculture (3.68%). A systematic observation network on a national scale should be established to conduct a long-term monitoring atmospheric Sdep (including wet and dry deposition), based on exiting ecological stations administrated by different departments in China.

  19. Reduction in density of suspended - sediment - laden natural waters

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.; Desa, E.; Desa, E.; Smith, D.; Peshwe, V.B.; VijayKumar, K.; Desa, J.A.E.

    Pressure measurements made in various turbid natural waters have led to the inference that the effective depth-mean in-situ density values peff of these waters are less than (approx equal to 2.70%) their static bulk densities and also (approx equal...

  20. Efficient organic photovoltaic cells with vertically ordered bulk heterojunctions.

    Science.gov (United States)

    Yu, Bo; Wang, Haibo; Yan, Donghang

    2013-12-01

    Nanoscale morphology has been proved to be the key parameter deciding the exciton dissociation and charge transportation in bulk heterojunction (BHJ) solar cells. In this paper, we report a kind of small molecular organic photovoltaic cell (OPV) with a vertically ordered BHJ prepared by the weak epitaxial growth method. By this method, zinc phthalocyanine (ZnPc) can easily be formed into a highly ordered and continuous thin film and C60 is inclined to become dispersed crystalline grains in ZnPc film. Furthermore, we can control both the size and distribution density of C60 crystalline grains in ZnPc thin film without destroying the order of the ZnPc thin film. The OPVs with the vertically ordered BHJ show a high fill factor and a power conversion efficiency over 3% has been achieved.

  1. Does Bulk Viscosity Create a Viable Unified Dark Matter Model?

    CERN Document Server

    Li, Baojiu

    2009-01-01

    We investigate in detail the possibility that a single imperfect fluid with bulk viscosity can replace the need for separate dark matter and dark energy in cosmological models. With suitable choices of model parameters, we show that the background cosmology in this model can mimic that of a LCDM Universe to high precision. However, as the cosmic expansion goes through the decelerating-accelerating transition, the density perturbations in this fluid are rapidly damped out. We show that,although this does not significantly affect structure formation in baryonic matter, it makes the gravitational potential decay rapidly at late times, leading to modifications in predictions of cosmological observables such as the CMB power spectrum and weak lensing. This model of unified dark matter is thus difficult to reconcile with astronomical observations. We also clarify the differences with respect to other unified dark matter models where the fluid is barotropic, i.e., p=p(rho), such as the (generalized) Chaplygin gas mo...

  2. Microwave losses of bulk CaC{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Cifariello, G.; Di Gennaro, E. [CNISM and Department of Physics, University of Naples ' Federico II' , 80125 Naples (Italy); Lamura, G. [CNR-INFM Coherentia and Department of Physics, University of Naples ' Federico II' , 80125 Naples (Italy); Andreone, A. [CNISM and Department of Physics, University of Naples ' Federico II' , 80125 Naples (Italy)], E-mail: andreone@unina.it; Emery, N.; Herold, C.; Mareche, J.F.; Lagrange, P. [Laboratoire de Chimie du Solide Mineral-UMR 7555, Universite Henri Poincare Nancy I, B.P. 239, 54506 Vandoeuvre-les-Nancy Cedex (France)

    2007-09-01

    We report a study of the temperature dependence of the surface resistance R{sub S} in the graphite intercalated compound (GIC) CaC{sub 6}, where superconductivity at 11.5 K was recently discovered. Experiments are carried out using a copper dielectrically loaded cavity operating at 7 GHz in a 'hot finger' configuration. Bulk CaC{sub 6} samples have been synthesized from highly oriented pyrolytic graphite. Microwave data allow to extract unique information on the quasiparticle density and on the nature of pairing in superconductors. The analysis of R{sub S}(T) confirms our recent experimental findings that CaC{sub 6} behaves as a weakly-coupled, fully gapped, superconductor.

  3. Direct determination of bulk etching rate for LR-115-II solid state nuclear track detectors

    Indian Academy of Sciences (India)

    T A Salama; U Seddik; T M Heggazy; A Ahmed Morsy

    2006-09-01

    The thickness of the removed layer of the LR-115-II solid state nuclear track detector during etching is measured directly with a rather precise instrument. Dependence of bulk etching rate on temperature of the etching solution is investigated. It has been found that the bulk etching rate is 3.2 m/h at 60°C in 2.5 N NaOH of water solution. It is also found that the track density in detectors exposed to soil samples increases linearly with the removed layer.

  4. NPP bulk equipment dismantling problems and experience

    International Nuclear Information System (INIS)

    NPP bulk equipment dismantling problems and experience are summarized. 'ECOMET-S' JSC is shown as one of the companies which are able to make NPPs industrial sites free from stored bulk equipment with its further utilization. 'ECOMET-S' JSC is the Russian Federation sole specialized metallic LLW (MLLW) treatment and utilization facility. Company's main objectives are waste predisposal volume reduction and treatment for the unrestricted release as a scrap. Leningrad NPP decommissioned main pumps and moisture separators/steam super heaters dismantling results are presented. Prospective fragmentation technologies (diamond and electro-erosive cutting) testing results are described. The electro-erosive cutting machine designed by 'ECOMET-S' JSC is presented. The fragmentation technologies implementation plans for nuclear industry are presented too. (author)

  5. Bulk and shear viscosity in Hagedorn fluid

    Energy Technology Data Exchange (ETDEWEB)

    Tawfik, A.; Wahba, M. [Egyptian Center for Theoretical Physics (ECTP), MTI University, Faculty of Engineering, Cairo (Egypt)

    2010-11-15

    Assuming that the Hagedorn fluid composed of known particles and resonances with masses m <2 GeV obeys the first-order theory (Eckart) of relativistic fluid, we discuss the transport properties of QCD confined phase. Based on the relativistic kinetic theory formulated under the relaxation time approximation, expressions for bulk and shear viscosity in thermal medium of hadron resonances are derived. The relaxation time in the Hagedorn dynamical fluid exclusively takes into account the decay and eventually van der Waals processes. We comment on the in-medium thermal effects on bulk and shear viscosity and averaged relaxation time with and without the excluded-volume approach. As an application of these results, we suggest the dynamics of heavy-ion collisions, non-equilibrium thermodynamics and the cosmological models, which require thermo- and hydro-dynamics equations of state. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  6. Bulk and Shear Viscosity in Hagedorn Fluid

    CERN Document Server

    Tawfik, A

    2010-01-01

    Assuming that the Hagedorn fluid composed of known particles and resonances with masses $m<2\\,$GeV obeys the {\\it first-order} theory (Eckart) of relativistic fluid, we discuss the transport properties of QCD confined phase. Based on the relativistic kinetic theory formulated under the relaxation time approximation, expressions for bulk and shear viscosity in thermal medium are derived. The relaxation time in the Hagedorn dynamical fluid exclusively takes into account the decay and eventually van der Waals processes. We comment on the {\\it in-medium} thermal effects on bulk and shear viscosities and averaged relaxation time with and without the excluded-volume approach. As an application of these results, we suggest the dynamics of heavy-ion collisions, non-equlibrium thermodynamics and the cosmological models, which require thermo and hydrodynamics equations of state.

  7. Bulk Locality and Boundary Creating Operators

    CERN Document Server

    Nakayama, Yu

    2015-01-01

    We formulate a minimum requirement for CFT operators to be localized in the dual AdS. In any spacetime dimensions, we show that a general solution to the requirement is a linear superposition of operators creating spherical boundaries in CFT, with the dilatation by the imaginary unit from their centers. This generalizes the recent proposal by Miyaji et al. for bulk local operators in the three dimensional AdS. We show that Ishibashi states for the global conformal symmetry in any dimensions and with the imaginary dilatation obey free field equations in AdS and that incorporating bulk interactions require their superpositions. We also comment on the recent proposals by Kabat et al., and by H. Verlinde.

  8. Bulk band gaps in divalent hexaborides

    Energy Technology Data Exchange (ETDEWEB)

    Denlinger, Jonathan; Clack, Jules A.; Allen, James W.; Gweon, Gey-Hong; Poirier, Derek M.; Olson, Cliff G.; Sarrao, John L.; Bianchi, Andrea D.; Fisk, Zachary

    2002-08-01

    Complementary angle-resolved photoemission and bulk-sensitive k-resolved resonant inelastic x-ray scattering of divalent hexaborides reveal a >1 eV X-point gap between the valence and conduction bands, in contradiction to the band overlap assumed in several models of their novel ferromagnetism. This semiconducting gap implies that carriers detected in transport measurements arise from defects, and the measured location of the bulk Fermi level at the bottom of the conduction band implicates boron vacancies as the origin of the excess electrons. The measured band structure and X-point gap in CaB6 additionally provide a stringent test case for proper inclusion of many-body effects in quasi-particle band calculations.

  9. Brane plus Bulk Supersymmetry in Ten Dimensions

    CERN Document Server

    Bergshoeff, E A; Ortín, Tomas; Roest, D; Van Proeyen, A

    2001-01-01

    We discuss a generalized form of IIA/IIB supergravity depending on all R-R potentials C^(p) (p=0,1,...,9) as the effective field theory of Type IIA/IIB superstring theory. For the IIA case we explicitly break this R-R democracy to either p=5 which allows us to write a new bulk action that can be coupled to N=1 supersymmetric brane actions. The case of 8-branes is studied in detail using the new bulk & brane action. The supersymmetric negative tension branes without matter excitations can be viewed as orientifolds in the effective action. These D8-branes and O8-planes are fundamental in Type I' string theory. A BPS 8-brane solution is given which satisfies the jump conditions on the wall. As an application of our results we derive a quantization of the mass parameter and the cosmological constant in string units.

  10. Surface-Bulk Vibrational Correlation Spectroscopy.

    Science.gov (United States)

    Roy, Sandra; Covert, Paul A; Jarisz, Tasha A; Chan, Chantelle; Hore, Dennis K

    2016-05-01

    Homo- and heterospectral correlation analysis are powerful methods for investigating the effects of external influences on the spectra acquired using distinct and complementary techniques. Nonlinear vibrational spectroscopy is a selective and sensitive probe of surface structure changes, as bulk molecules are excluded on the basis of symmetry. However, as a result of this exquisite specificity, it is blind to changes that may be occurring in the solution. We demonstrate that correlation analysis between surface-specific techniques and bulk probes such as infrared absorption or Raman scattering may be used to reveal additional details of the adsorption process. Using the adsorption of water and ethanol binary mixtures as an example, we illustrate that this provides support for a competitive binding model and adds new insight into a dimer-to-bilayer transition proposed from previous experiments and simulations. PMID:27058265

  11. Bulk entropy in loop quantum gravity

    Energy Technology Data Exchange (ETDEWEB)

    Livine, Etera R. [Laboratoire de Physique ENS Lyon, CNRS UMR 5672, 46 Allee d' Italie, 69364 Lyon Cedex 07 (France)], E-mail: etera.livine@ens-lyon.fr; Terno, Daniel R. [Centre for Quantum Computer Technology, Department of Physics, Macquarie University, Sydney NSW 2109 (Australia)], E-mail: dterno@physics.mq.edu.au

    2008-05-01

    In the framework of loop quantum gravity (LQG), we generalize previous boundary state counting for black hole entropy [E.R. Livine, D.R. Terno, Quantum black holes: Entropy and entanglement on the horizon, Nucl. Phys. B 741 (2006) 131, (gr-qc/0508085)] to a full bulk state counting. After suitable gauge fixing, we show how to compute the bulk entropy of a bounded region of space (the 'black hole') with fixed boundary conditions. This allows to study in detail the relationship between the entropy and the boundary area and to identify a holographic regime for LQG where the leading order of the entropy scales with the area. In this regime we can fine tune the factor between entropy and area without changing the Immirzi parameter.

  12. Raman characterization of bulk ferromagnetic nanostructured graphite

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, Helena, E-mail: hpardo@fq.edu.uy [Centro NanoMat, Polo Tecnologico de Pando, Facultad de Quimica, Universidad de la Republica, Cno. Aparicio Saravia s/n, 91000, Pando, Canelones (Uruguay); Crystallography, Solid State and Materials Laboratory (Cryssmat-Lab), DETEMA, Facultad de Quimica, Universidad de la Republica, Gral. Flores 2124, P.O. Box 1157, Montevideo (Uruguay); Divine Khan, Ngwashi [Mantfort University, Leicester (United Kingdom); Faccio, Ricardo [Centro NanoMat, Polo Tecnologico de Pando, Facultad de Quimica, Universidad de la Republica, Cno. Aparicio Saravia s/n, 91000, Pando, Canelones (Uruguay); Crystallography, Solid State and Materials Laboratory (Cryssmat-Lab), DETEMA, Facultad de Quimica, Universidad de la Republica, Gral. Flores 2124, P.O. Box 1157, Montevideo (Uruguay); Araujo-Moreira, F.M. [Grupo de Materiais e Dispositivos-CMDMC, Departamento de Fisica e Engenharia Fisica, UFSCar, Caixa Postal 676, 13565-905, Sao Carlos SP (Brazil); Fernandez-Werner, Luciana [Centro NanoMat, Polo Tecnologico de Pando, Facultad de Quimica, Universidad de la Republica, Cno. Aparicio Saravia s/n, 91000, Pando, Canelones (Uruguay); Crystallography, Solid State and Materials Laboratory (Cryssmat-Lab), DETEMA, Facultad de Quimica, Universidad de la Republica, Gral. Flores 2124, P.O. Box 1157, Montevideo (Uruguay)

    2012-08-15

    Raman spectroscopy was used to characterize bulk ferromagnetic graphite samples prepared by controlled oxidation of commercial pristine graphite powder. The G:D band intensity ratio, the shape and position of the 2D band and the presence of a band around 2950 cm{sup -1} showed a high degree of disorder in the modified graphite sample, with a significant presence of exposed edges of graphitic planes as well as a high degree of attached hydrogen atoms.

  13. Material profile influences in bulk-heterojunctions

    OpenAIRE

    Roehling, J.D.; Rochester, C.W.; Ro, H.W.; Wang, P.; Majewski, J; Batenburg, Joost; Arslan, I; Delongchamp, D.M.; Moulé, A.J.

    2014-01-01

    The morphology in mixed bulk-heterojunction films are compared using three different quantitative measurement techniques. We compare the vertical composition changes using high-angle annular dark-field scanning transmission electron microscopy with electron tomography and neutron and x-ray reflectometry. The three measurement techniques yield qualitatively comparable vertical concentration measurements. The presence of a metal cathode during thermal annealing is observed to alter the fulleren...

  14. Superconducting RF cavities film of bulk

    CERN Document Server

    Darriulat, Pierre

    1999-01-01

    The successful operation of LEP2 has demonstrated the feasibility of using on a large scale copper accelerating cavities coated with a thin superconducting niobium film. Yet other existing or planned installations such as CEBAF and TESLA, rely instead on the bulk niobium technology. The reason is a wide spread belief that the film technology would suffer from fundamental limitations preventing high gradients to be reached...

  15. Depleted Bulk Heterojunction Colloidal Quantum Dot Photovoltaics

    KAUST Repository

    Barkhouse, D. Aaron R.

    2011-05-26

    The first solution-processed depleted bulk heterojunction colloidal quantum dot solar cells are presented. The architecture allows for high absorption with full depletion, thereby breaking the photon absorption/carrier extraction compromise inherent in planar devices. A record power conversion of 5.5% under simulated AM 1.5 illumination conditions is reported. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Note on the Measurement of Bulk Density and Tapped Density of Powders According to the European Pharmacopeia

    OpenAIRE

    e Silva, J. P. Sousa; Splendor, D.; Gonçalves, I. M. B.; Costa, P.; Sousa Lobo, J. M.

    2013-01-01

    The apparent volume and compressibility index of commonly used excipients were evaluated according to European Pharmacopeia monograph (seventh edition) in order to study the influence of the procedure conditions. The results suggested that the leveling of the powder inside the cylinder ought to be avoided.

  17. Evidence for Bulk Ripplocations in Layered Solids

    Science.gov (United States)

    Gruber, Jacob; Lang, Andrew C.; Griggs, Justin; Taheri, Mitra L.; Tucker, Garritt J.; Barsoum, Michel W.

    2016-01-01

    Plastically anisotropic/layered solids are ubiquitous in nature and understanding how they deform is crucial in geology, nuclear engineering, microelectronics, among other fields. Recently, a new defect termed a ripplocation–best described as an atomic scale ripple–was proposed to explain deformation in two-dimensional solids. Herein, we leverage atomistic simulations of graphite to extend the ripplocation idea to bulk layered solids, and confirm that it is essentially a buckling phenomenon. In contrast to dislocations, bulk ripplocations have no Burgers vector and no polarity. In graphite, ripplocations are attracted to other ripplocations, both within the same, and on adjacent layers, the latter resulting in kink boundaries. Furthermore, we present transmission electron microscopy evidence consistent with the existence of bulk ripplocations in Ti3SiC2. Ripplocations are a topological imperative, as they allow atomic layers to glide relative to each other without breaking the in-plane bonds. A more complete understanding of their mechanics and behavior is critically important, and could profoundly influence our current understanding of how graphite, layered silicates, the MAX phases, and many other plastically anisotropic/layered solids, deform and accommodate strain. PMID:27640724

  18. Cosmological Implications of QGP Bulk Viscosity

    CERN Document Server

    Anand, Sampurn; Bhatt, Jitesh R

    2016-01-01

    Recent studies of the hot QCD matter indicate that the bulk viscosity ($\\zeta$) of quark-gluon plasma (QGP) rises sharply near the critical point of the QCD phase transition. In this work, we show that such a sharp rise of the bulk viscosity will lead to an effective negative pressure near the critical temperature, $T_{c}$ which in turn drives the Universe to inflate. This inflation has a natural graceful exist when the viscous effect evanesce. We estimate that, depending upon the peak value of $\\zeta$, universe expands by a factor of $10$ to $80$ times in a very short span ($\\Delta t\\sim 10^{-8}$ seconds). Another important outcome of the bulk viscosity dominated dynamics is the cavitation of QGP around $T \\sim 1.5T_{c}$. This would lead to the phenomenon of formation of cavitation bubbles within the QGP phase. The above scenario is independent of the order of QCD phase transition. We delineate some of the important cosmological consequences of the inflation and the cavitation.

  19. Superconducting State Parameters of Bulk Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Aditya M. Vora

    2012-12-01

    Full Text Available Well recognized empty core (EMC pseudopotential of Ashcroft is used to investigate the superconducting state parameters viz; electron-phonon coupling strength λ, Coulomb pseudopotential μ*, transition temperature TC, isotope effect exponent α and effective interaction strength NOV of some (Ni33Zr671 – xVx (x = 0, 0.05, 0.1, 0.15 bulk amorphous alloys. We have incorporated five different types of local field correction functions, proposed by Hartree (H, Taylor (T, Ichimaru-Utsumi (IU, Farid et al. (F and Sarkar et al. (S to show the effect of exchange and correlation on the aforesaid properties. Very strong influence of the various exchange and correlation functions is concluded from the present study. The TC obtained from Sarkar et al. (S local field correction function are found an excellent agreement with available theoretical data. Quadratic TC equation has been proposed, which provide successfully the TC values of bulk amorphous alloys under consideration. Also, the present results are found in qualitative agreement with other such earlier reported data, which confirms the superconducting phase in the s bulk amorphous alloys.

  20. Evidence for Bulk Ripplocations in Layered Solids

    Science.gov (United States)

    Gruber, Jacob; Lang, Andrew C.; Griggs, Justin; Taheri, Mitra L.; Tucker, Garritt J.; Barsoum, Michel W.

    2016-09-01

    Plastically anisotropic/layered solids are ubiquitous in nature and understanding how they deform is crucial in geology, nuclear engineering, microelectronics, among other fields. Recently, a new defect termed a ripplocation–best described as an atomic scale ripple–was proposed to explain deformation in two-dimensional solids. Herein, we leverage atomistic simulations of graphite to extend the ripplocation idea to bulk layered solids, and confirm that it is essentially a buckling phenomenon. In contrast to dislocations, bulk ripplocations have no Burgers vector and no polarity. In graphite, ripplocations are attracted to other ripplocations, both within the same, and on adjacent layers, the latter resulting in kink boundaries. Furthermore, we present transmission electron microscopy evidence consistent with the existence of bulk ripplocations in Ti3SiC2. Ripplocations are a topological imperative, as they allow atomic layers to glide relative to each other without breaking the in-plane bonds. A more complete understanding of their mechanics and behavior is critically important, and could profoundly influence our current understanding of how graphite, layered silicates, the MAX phases, and many other plastically anisotropic/layered solids, deform and accommodate strain.

  1. Evidence for Bulk Ripplocations in Layered Solids.

    Science.gov (United States)

    Gruber, Jacob; Lang, Andrew C; Griggs, Justin; Taheri, Mitra L; Tucker, Garritt J; Barsoum, Michel W

    2016-01-01

    Plastically anisotropic/layered solids are ubiquitous in nature and understanding how they deform is crucial in geology, nuclear engineering, microelectronics, among other fields. Recently, a new defect termed a ripplocation-best described as an atomic scale ripple-was proposed to explain deformation in two-dimensional solids. Herein, we leverage atomistic simulations of graphite to extend the ripplocation idea to bulk layered solids, and confirm that it is essentially a buckling phenomenon. In contrast to dislocations, bulk ripplocations have no Burgers vector and no polarity. In graphite, ripplocations are attracted to other ripplocations, both within the same, and on adjacent layers, the latter resulting in kink boundaries. Furthermore, we present transmission electron microscopy evidence consistent with the existence of bulk ripplocations in Ti3SiC2. Ripplocations are a topological imperative, as they allow atomic layers to glide relative to each other without breaking the in-plane bonds. A more complete understanding of their mechanics and behavior is critically important, and could profoundly influence our current understanding of how graphite, layered silicates, the MAX phases, and many other plastically anisotropic/layered solids, deform and accommodate strain. PMID:27640724

  2. Bulk Comptonization by turbulence in accretion discs

    Science.gov (United States)

    Kaufman, J.; Blaes, O. M.

    2016-06-01

    Radiation pressure dominated accretion discs around compact objects may have turbulent velocities that greatly exceed the electron thermal velocities within the disc. Bulk Comptonization by the turbulence may therefore dominate over thermal Comptonization in determining the emergent spectrum. Bulk Comptonization by divergenceless turbulence is due to radiation viscous dissipation only. It can be treated as thermal Comptonization by solving the Kompaneets equation with an equivalent `wave' temperature, which is a weighted sum over the power present at each scale in the turbulent cascade. Bulk Comptonization by turbulence with non-zero divergence is due to both pressure work and radiation viscous dissipation. Pressure work has negligible effect on photon spectra in the limit of optically thin turbulence, and in this limit radiation viscous dissipation alone can be treated as thermal Comptonization with a temperature equivalent to the full turbulent power. In the limit of extremely optically thick turbulence, radiation viscous dissipation is suppressed, and the evolution of local photon spectra can be understood in terms of compression and expansion of the strongly coupled photon and gas fluids. We discuss the consequences of these effects for self-consistently resolving and interpreting turbulent Comptonization in spectral calculations in radiation magnetohydrodynamic simulations of high luminosity accretion flows.

  3. Implications of PCR and ELISA results on the routes of bulk-tank contamination with Mycobacterium avium ssp. paratuberculosis.

    Science.gov (United States)

    Beaver, A; Cazer, C L; Ruegg, P L; Gröhn, Y T; Schukken, Y H

    2016-02-01

    Mycobacterium avium ssp. paratuberculosis (MAP), the etiologic agent of Johne's disease in dairy cattle, may enter the bulk tank via environmental contamination or direct excretion into milk. Traditionally, diagnostics to identify MAP in milk target either MAP antibodies (by ELISA) or the organism itself (by culture or PCR). High ELISA titers may be directly associated with excretion of MAP into milk but only indirectly linked to environmental contamination of the bulk tank. Patterns of bulk-milk ELISA and bulk-milk PCR results could therefore provide insight into the routes of contamination and level of infection or environmental burden. Coupled with questionnaire responses pertaining to management, the results of these diagnostic tests could reveal correlations with herd characteristics or on-farm practices that distinguish herds with high and low environmental bulk-tank MAP contamination. A questionnaire on hygiene, management, and Johne's specific parameters was administered to 292 dairy farms in New York, Oregon, and Wisconsin. Bulk-tank samples were collected from each farm for evaluation by real-time PCR and ELISA. Before DNA extraction and testing of the unknown samples, bulk-milk template preparation was optimized with respect to parameters such as MAP fractionation patterns and lysis. Two regression models were developed to explore the relationships among bulk-tank PCR, ELISA, environmental predictors, and herd characteristics. First, ELISA optical density (OD) was designated as the outcome in a linear regression model. Second, the log odds of being PCR positive in the bulk tank were modeled using binary logistic regression with penalized maximum likelihood. The proportion of PCR-positive bulk tanks was highest for New York and for organic farms, providing a clue as to the geographical patterns of MAP-positive bulk-tank samples and relationship to production type. Bulk-milk PCR positivity was also higher for large relative to small herds. The models

  4. QCD phase transition with a power law chameleon scalar field in the bulk

    CERN Document Server

    Golanbari, T; Saaidi, Kh

    2014-01-01

    In this work, a brane world model with a perfect fluid on brane and a scalar field on bulk has been used to study quark-hadron phase transition. The bulk scalar field has an interaction with brane matter. This interaction comes into non-conservation relation which describe an energy transfer between bulk and brane. Since quark-hadron transition curly depends on the form of evolution equations therefore modification of energy conservation equation and Friedmann equation comes into some interesting results about the time of transition. The evolution of physical quantities relevant to quantitative of early times namely energy density $\\rho$ temperature $T$ and scale factor $a$ have been considered utilizing two formalisms as crossover formalism and first order phase transition formalism. The results show that the quark-hadron phase transition in occurred about nanosecond after big bang and the general behavior temperature is similar in both of two formalism.

  5. QCD phase transition with a power law chameleon scalar field in the bulk

    Science.gov (United States)

    Golanbari, Tayeb; Mohammadi, Abolhassan; Saaidi, Khaled

    2014-03-01

    In this paper, a braneworld model with a perfect fluid on brane and a scalar field on bulk has been used to study quark-hadron phase transition. The bulk scalar field has an interaction with brane matter. This interaction comes into nonconservation relation which describes an energy transfer between bulk and brane. Since quark-hadron transition truly depends on the form of evolution equations, modification of energy conservation equation and Friedmann equation gives rise to some interesting results about the time of transition. The evolution of physical quantities relevant to the quantitative of early times namely energy density ρ, temperature T and scale factor a have been considered utilizing two formalism, crossover formalism and first-order phase transition formalism. The results show that the quark-hadron phase transition occurred about a nanosecond after big bang and the general behavior temperature is similar in both of two formalism.

  6. Effects of Oxygen Vacancy on Optical and Electrical Properties of ZnO Bulks and Nanowires

    Science.gov (United States)

    Yu, Xiao-Xia; Zheng, Hong-Mei; Fang, Xiao-Yong; Jin, Hai-Bo; Cao, Mao-Sheng

    2014-11-01

    Based on the generalized gradient approximation (GGA) in density functional theory (DFT) and using the first-principle plane wave ultrasoft pseudopotential method, we construct and optimize the structures of intrinsic and oxygen vacancy (VO) ZnO bulks and nanowires (NWs) in the Castep module. Moreover, the calculation of band structures and the optical properties are carried out. The calculated results exhibit that the oxygen vacancy exerts a more significant influence on the electronic structures of the ZnO bulks instead of the NWs. What is more, the influences of the VO on the optical properties are mainly embodied in the ultraviolet region, and the main optical parameters of ZnO bulks and NWs with VO are anisotropic.

  7. Ultra-soft x-ray absorption spectroscopy: A bulk and surface probe of materials

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, D.A. [National Institute of Standards and Technology, Gaithersburg, MD (United States); Mitchell, G.E.; Dekoven, B.M. [Dow Chemical Co., Midland, MI (United States); Yeh, A.T.; Gland, J.L. [Michigan Univ., Ann Arbor, MI (United States); Moodenbaugh, A.R. [Brookhaven National Lab., Upton, NY (United States)

    1993-06-01

    Direct comparisons between surface and bulk of diverse materials can be made by simultaneous electron yield (5 nm depth sensitivity) and fluorescence yield (200 nm) ultra soft x-ray absorption spectroscopy measurements utilizing a rapid sample interchange apparatus. For example the orientations of functional groups have been characterized at and near the surface of a series of model polymeric materials highlighting the chemical and molecular sensitivity of ultra soft x-ray absorption spectroscopy. In addition we discuss a bulk sensitive use of fluorescence yield to non destructively study a buried metal polymer interface. A second bulk sensitive example is the use of fluorescence yield oxygen K near edge x-ray spectroscopy as a method to determine the hole state density of high Tc materials.

  8. Ultra-soft x-ray absorption spectroscopy: A bulk and surface probe of materials

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, D.A. (National Institute of Standards and Technology, Gaithersburg, MD (United States)); Mitchell, G.E.; Dekoven, B.M. (Dow Chemical Co., Midland, MI (United States)); Yeh, A.T.; Gland, J.L. (Michigan Univ., Ann Arbor, MI (United States)); Moodenbaugh, A.R. (Brookhaven National Lab., Upton, NY (United States))

    1993-01-01

    Direct comparisons between surface and bulk of diverse materials can be made by simultaneous electron yield (5 nm depth sensitivity) and fluorescence yield (200 nm) ultra soft x-ray absorption spectroscopy measurements utilizing a rapid sample interchange apparatus. For example the orientations of functional groups have been characterized at and near the surface of a series of model polymeric materials highlighting the chemical and molecular sensitivity of ultra soft x-ray absorption spectroscopy. In addition we discuss a bulk sensitive use of fluorescence yield to non destructively study a buried metal polymer interface. A second bulk sensitive example is the use of fluorescence yield oxygen K near edge x-ray spectroscopy as a method to determine the hole state density of high Tc materials.

  9. Carbon diffusion in bulk hcp zirconium: A multi-scale approach

    Science.gov (United States)

    Xu, Y.; Roques, J.; Domain, C.; Simoni, E.

    2016-05-01

    In the framework of the geological repository of the used fuel claddings of pressurized water reactor, carbon behavior in bulk zirconium is studied by periodic Density Functional Theory calculations. The C interstitial sites were investigated and it was found that there are two possible carbon interstitial sites: a distorted basal tetragonal site and an octahedral site. There are four types of possible atomic jumps between them. After calculating the migration energies, the attempt frequencies and the jump probabilities for each possible migration path, kinetic Monte Carlo (KMC) simulations were performed to simulate carbon diffusion at the macroscopic scale. The results show that carbon diffusion in pure Zr bulk is extremely limited at the storage temperature (50 °C). Since there are defects in Zr bulk, in a second step, the effect of atomic vacancy was studied and it was proved that vacancies cannot increase carbon diffusion.

  10. A Stochastic Closure for Two-Moment Bulk Microphysics of Warm Clouds: Part I, Derivations

    CERN Document Server

    Collins, David

    2015-01-01

    We propose a mathematical methodology to derive a stochastic parameterization of bulk warm cloud micro-physics properties. Unlike previous bulk parameterizations, the stochastic parameterization does not assume any particular droplet size distribution, all parameters have physical meanings which are recoverable from data, and the resultant parameterization has the flexibility to utilize a variety of collision kernels. Our strategy is a new two-fold approach to modelling the kinetic collection equation. Partitioning the droplet spectrum into cloud and rain aggregates, we represent droplet densities as the sum of a mean and a random fluctuation. Moreover, we use a Taylor approximation for the collision kernel which allows the resulting parameterization to be independent of the collision kernel. To address the two-moment closure for bulk microphysical equations, we represent the higher (third) order terms as points in an Ornstein-Uhlenbeck-like stochastic process. These higher order terms are aggregate number co...

  11. Density and permeability of a loess soil

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Schjønning, Per; Møldrup, Per;

    2013-01-01

    Long-term field trials provide an ideal means to assess effects of cultivation practises (e.g., fertilisation, tillage, crop rotation etc.) on soil physical properties and soil fertility. To build upon the knowledge of the role of organic carbon (OC) and other soil properties on soil response......Pa). Investigated indicators for compression resistance included compression index, precompression stress, and resistance and resilience indices based on measured soil physical properties (bulk density, air-filled porosity, air permeability, and void ratio). Soil resilience was assessed following exposure...... of compacted cores to freeze-thaw (FT) and wet-dry (WD) cycles. The OC content increased with increased fertilisation and resulted in decreased initial bulk density, higher air-filled and total porosities, and increased organisation of the pore space. Soil resistance decreased with increasing OC content...

  12. Prediction of bulk properties of Fischer-Tropsch derived liquids

    Energy Technology Data Exchange (ETDEWEB)

    Marano, J.J.; Holder, G.D. [Univ. of Pittsburgh, PA (United States). Dept. of Chemical and Petroleum Engineering

    1997-06-01

    Asymptotic behavior correlations (ABCs) based on the properties of pure n-paraffins are used to predict the bulk properties of liquid mixtures derived from the Fischer-Tropsch synthesis. Comparisons are made with literature data for congealing point, density, specific heat, viscosity, thermal conductivity, and surface tension. Mixture property predictions are based on appropriate average carbon numbers and on a general property mixing rule. Both ideal and nonideal solution behavior are exhibited. For the nonideal properties, viscosity and surface tension, mixing rules are proposed and parameters regressed to obtain reasonable agreement with mixture data. Property estimates based on the appropriate average carbon number are probably sufficient for most engineering applications. Methods are outlined for estimating different carbon-number averages based on congealing- and melting-point, density, and the Anderson-Schulz-Flory distribution when the carbon number distribution of the mixture is not available. The presence of other Fischer-Tropsch byproducts appears to have little effect on the accuracy of predictions made for high molecular weight mixtures.

  13. Correlations between critical parameters and bulk properties of nuclear matter

    CERN Document Server

    Lourenço, O; Dutra, M; Delfino, A

    2016-01-01

    The present work starts by providing a clear identification of correlations between critical parameters ($T_c$, $P_c$, $\\rho_c$) and bulk quantities at zero temperature of relativistic mean-field models (RMF) presenting third and fourth order self-interactions in the scalar field $\\sigma$. Motivated by the nonrelativistic version of this RMF model, we show that effective nucleon mass ($M^*$) and incompressibility ($K_o$), at the saturation density, are correlated with $T_c$, $P_c$, and $\\rho_c$, as well as, binding energy and saturation density itself. We verify agreement of results with previous theoretical ones regarding different hadronic models. Concerning recent experimental data of the symmetric nuclear matter critical parameters, our study allows a prediction of $T_c$, $P_c$ and $\\rho_c$ compatible with such values, by combining them, through the correlations found, with previous constraints related to $M^*$ and $K_o$. An improved RMF parametrization, that better agrees with experimental values for $T_...

  14. Silicon surface and bulk defect passivation by low temperature PECVD oxides and nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z.; Rohatgi, A. [Georgia Institute of Technology, Atlanta, GA (United States). Univ. Center of Excellence for Photovoltaics Research and Education; Ruby, D. [Sandia National Labs., Albuquerque, NM (United States)

    1995-01-01

    The effectiveness of PECVD passivation of surface and bulk defects in Si, as well as phosphorous diffused emitters, Is investigated and quantified. Significant hydrogen incorporation coupled with high positive charge density in the PECVD SiN layer is found to play an important role in bulk and surface passivation. It is shown that photo-assisted anneal in a forming gas ambient after PECVD depositions significantly improves the passivation of emitter and bulk defects. PECVD passivation of phosphorous doped emitters and boron doped bare Si surfaces is found to be a strong function of doping concentration. Surface recombination velocity of less than 200 cm/s for 0.2 Ohm-cm and less than 1 cm/s for high resistivity substrates ({approximately} Ohm-cm) were achieved. PECVD passivation improved bulk lifetime in the range of 30% to 70% in multicrystalline Si materials. However, the degree of the passivation was found to be highly material specific. Depending upon the passivation scheme, emitter saturation current density (J{sub oe}) can be reduced by a factor of 3 to 9. Finally, the stability of PECVD oxide/nitride passivation under prolonged UV exposure is established.

  15. Superconductors, analysis and applications, with special reference to the utilisation of bulk (Re)BCO materials

    Science.gov (United States)

    Coombs, T. A.

    2010-11-01

    The Electrical Power and Energy Conversion (EPEC) superconductivity group at Cambridge University has been working on the application of superconductivity to large scale devices. This work is taking place over a range of areas which cover FCLs, motors and generators, SMES, accelerator magnets and MRI. The research is underpinned by advanced modelling techniques using both pure Critical State models and E- J models to analyse the behaviour of the superconductors. As part of the device design we are concentrating on the analysis of AC losses in complicated geometries such as are found in motor windings and the magnetisation of bulk superconductors to enable their full potential to be realised. We are interested in the full range of high-temperature superconductors and have measured and predicted the performance of YBCO, MgB 2 and BSCCO at a range of temperatures and in wire, tape and bulk forms. This paper concentrates on recent work which includes: modelling of coils using formulations based on H and A. A critical state model for the analysis of coils in SMES; crossed field effects in bulk superconductors; a magnetic model together with experimental results which explain and describe the method of flux pumping whereby a bulk superconductor can be magnetised to a high flux density using a repeatedly applied field of low flux density and finally a new configuration for MRI magnets

  16. Superconductors, analysis and applications, with special reference to the utilisation of bulk (Re)BCO materials

    Energy Technology Data Exchange (ETDEWEB)

    Coombs, T.A., E-mail: tac1000@cam.ac.u [University of Cambridge, Department of Engineering, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2010-11-01

    The Electrical Power and Energy Conversion (EPEC) superconductivity group at Cambridge University has been working on the application of superconductivity to large scale devices. This work is taking place over a range of areas which cover FCLs, motors and generators, SMES, accelerator magnets and MRI. The research is underpinned by advanced modelling techniques using both pure Critical State models and E-J models to analyse the behaviour of the superconductors. As part of the device design we are concentrating on the analysis of AC losses in complicated geometries such as are found in motor windings and the magnetisation of bulk superconductors to enable their full potential to be realised. We are interested in the full range of high-temperature superconductors and have measured and predicted the performance of YBCO, MgB{sub 2} and BSCCO at a range of temperatures and in wire, tape and bulk forms. This paper concentrates on recent work which includes: modelling of coils using formulations based on H and A. A critical state model for the analysis of coils in SMES; crossed field effects in bulk superconductors; a magnetic model together with experimental results which explain and describe the method of flux pumping whereby a bulk superconductor can be magnetised to a high flux density using a repeatedly applied field of low flux density and finally a new configuration for MRI magnets

  17. Randall-Sundrum II Cosmology, AdS/CFT, and the Bulk Black Hole

    CERN Document Server

    Hebecker, A

    2001-01-01

    We analyse the cosmology of a brane world model where a single brane carrying the standard model fields forms the boundary of a 5-dimensional AdS bulk (the Randall-Sundrum II scenario). We focus on the thermal radiation of bulk gravitons, the formation of the bulk black hole, and the holographic AdS/CFT definition of the RSII theory. Our detailed calculation of bulk radiation reduces previous estimates to a phenomenologically acceptable, although potentially visible level. In late cosmology, in which the Friedmann equation depends linearly on the energy density \\rho, only about 1% of energy density is lost to the black hole or, equivalently, to the `dark radiation' (\\Omega_{d,N} \\simeq 0.01 at nucleosynthesis). The preceding, unconventional \\rho^2 period can produce up to 10% dark radiation (\\Omega_{d,N} <\\sim 0.1). The AdS/CFT correspondence provides an equivalent description of late RSII cosmology. We show how the AdS/CFT formulation can reproduce the \\rho^2 correction to the standard treatment at low ma...

  18. Melt-growth bulk superconductors and application to an axial-gap-type rotating machine

    Science.gov (United States)

    Zhang, Yufeng; Zhou, Difan; Ida, Tetsuya; Miki, Motohiro; Izumi, Mitsuru

    2016-04-01

    The present manuscript addresses key issues in the course of our study of materials processing of bulk high-temperature superconductors, trapped flux and its application to a prototype axial-gap-type rotating machine. The TUMSAT group has conducted a series of studies since 2003 on the growth of GdBa2Cu3O7-δ bulk material and its application in a compact low-speed high-torque rotating machine. In the stage of material growth, gaining the advantage of a large motive torque density requires large integrated flux in the motor/generators. A large grain surface might be required with sophisticated techniques for the melt-growth texture in the bulk with optimal flux pinning. In the second stage, the in situ magnetization procedure for bulk superconductors in the applied machine is a crucial part of the technology. Pulsed current excitation by using an armature copper winding has magnetized field pole bulks on the rotor. The axial-gap flux synchronous machine studied in the past decade is a condensed technology and indicates that further scientific development is required for a future compact machine to be superior to conventional ones in accordance with the cryogenic periphery and flux stabilization.

  19. Levitation performance of the magnetized bulk high- Tc superconducting magnet with different trapped fields

    Science.gov (United States)

    Liu, W.; Wang, J. S.; Liao, X. L.; Zheng, S. J.; Ma, G. T.; Zheng, J.; Wang, S. Y.

    2011-03-01

    To a high- Tc superconducting (HTS) maglev system which needs large levitation force density, the magnetized bulk high- Tc superconductor (HTSC) magnet is a good candidate because it can supply additional repulsive or attractive force above a permanent magnet guideway (PMG). Because the induced supercurrent within a magnetized bulk HTSC is the key parameter for the levitation performance, and it is sensitive to the magnetizing process and field, so the magnetized bulk HTSC magnets with different magnetizing processes had various levitation performances, not only the force magnitude, but also its force relaxation characteristics. Furthermore, the distribution and configuration of the induced supercurrent are also important factor to decide the levitation performance, especially the force relaxation characteristics. This article experimentally investigates the influences of different magnetizing processes and trapped fields on the levitation performance of a magnetized bulk HTSC magnet with smaller size than the magnetic inter-pole distance of PMG, and the obtained results are qualitatively analyzed by the Critical State Model. The test results and analyses of this article are useful for the suitable choice and optimal design of magnetized bulk HTSC magnets.

  20. Evolution of bulk damage initiation in DKDP

    Science.gov (United States)

    Carr, Christopher W.; McMillian, T. H.; Staggs, Mike C.; Radousky, Harry B.; Demos, Stavros G.

    2003-05-01

    We investigate the evolution of laser-induced damage initiated in the bulk of DKDP crystals using in-situ microscopy. Experimental results indicate that at peek fluences greater than 10 J/cm2, damage sites are formed with increasing number as a function of the laser fluence. Following plasma formation, cracks are observed which grow in size for tens of seconds after the termination of the laser pulse. Subsequent irradiation leads to modest increase in size only during the initial 2-5 pulses. Experimental results suggest that there is also relaxation of the stresses adjacent to a damage site for several hours after initial damage.

  1. Hubble Parameter in Bulk Viscous Cosmology

    CERN Document Server

    Tawfik, A; Wahba, M

    2009-01-01

    We discuss influences of bulk viscosity on the Early Universe, which is modeled by Friedmann-Robertson-Walker metric and Einstein field equations. We assume that the matter filling the isotropic and homogeneous background is relativistic viscous characterized by ultra-relativistic equations of state deduced from recent lattice QCD simulations. We obtain a set of complicated differential equations, for which we suggest approximate solutions for Hubble parameter $H$. We find that finite viscosity in Eckart and Israel-Stewart fluids would significantly modify our picture about the Early Universe.

  2. Active neutron multiplicity counting of bulk uranium

    International Nuclear Information System (INIS)

    This paper describes a new nondestructive assay technique being developed to assay bulk uranium containing kilogram quantities of 235U. The new technique uses neutron multiplicity analysis of data collected with a coincidence counter outfitted with AmLi neutron sources. We have calculated the expected neutron multiplicity count rate and assay precision for this technique and will report on its expected performance as a function of detector design characteristics, 235U sample mass, AmLi source strength, and source-to-sample coupling. 11 refs., 2 figs., 2 tabs

  3. The bulk composition of exo-planets

    CERN Document Server

    Gaensicke, Boris; Dufour, Patrick; Farihi, Jay; Jura, Michael; Kilic, Mukremin; Melis, Carl; Veras, Dimitri; Xu, Siyi; Zuckerman, Ben

    2015-01-01

    Priorities in exo-planet research are rapidly moving from finding planets to characterizing their physical properties. Of key importance is their chemical composition, which feeds back into our understanding of planet formation. For the foreseeable future, far-ultraviolet spectroscopy of white dwarfs accreting planetary debris remains the only way to directly and accurately measure the bulk abundances of exo-planetary bodies. The exploitation of this method is limited by the sensitivity of HST, and significant progress will require a large-aperture space telescope with a high-throughput ultraviolet spectrograph.

  4. Neutron moisture gage for bulk material

    International Nuclear Information System (INIS)

    Desing and operation of neutron moisture gage of bulk materials intended for the determination of moisture of coke, agglomerated charge, and iron ore concentrate in black metallurgy is described. The moisture gage operates both under ''measurement'' and ''calibration'' conditions, contains a fast neutron source, and two groups of slow neutron detectors. Technical and economic efficiency of the moisture gage utilization consists in the improved accuracy of moisture detection at the expense of more accurate calibration, optimum arrangement of the carriage in a hopper, and stabilization of detector temperature. The device service is also simplified

  5. Improving the bulk data transfer experience

    Energy Technology Data Exchange (ETDEWEB)

    Guok, Chin; Guok, Chin; Lee, Jason R.; Berket, Karlo

    2008-05-07

    Scientific computations and collaborations increasingly rely on the network to provide high-speed data transfer, dissemination of results, access to instruments, support for computational steering, etc. The Energy Sciences Network is establishing a science data network to provide user driven bandwidth allocation. In a shared network environment, some reservations may not be granted due to the lack of available bandwidth on any single path. In many cases, the available bandwidth across multiple paths would be sufficient to grant the reservation. In this paper we investigate how to utilize the available bandwidth across multiple paths in the case of bulk data transfer.

  6. Failure by fracture in bulk metal forming

    DEFF Research Database (Denmark)

    Silva, C.M.A.; Alves, Luis M.; Nielsen, Chris Valentin;

    2015-01-01

    under loading conditions different from those found in conventional tests for bulk formability based on cylindrical,tapered and flanged specimens.The new formability test consists of expanding rings of various wall thicknesses with a stepped conical punch and allows investigating the onset of failure...... by cracking under three-dimensional states of stress subjected to various magnitudes of stress triaxiality.The presentation is supported by finite element analysis and experimentation in aluminium AA2030-T4 and results show that failure by fracture under three-dimensional loading conditions can be easily...

  7. Study on the bulk wave radiation of finite-length SAW devices using FEM/BEM

    Institute of Scientific and Technical Information of China (English)

    WANG Weibiao; ZHANG Xiaodong; SHUI Yongan; ZHANG De; HAN Tao

    2005-01-01

    Based on the distributions of stress and free charge on the interface of the surface acoustic wave (SAW) device calculated with the combination of boundary element method and finite element method(FEM/BEM), the power of each of the three possible bulk waves radiated by the SAW device is calculated, and their contributions to the overall input conductance are separated respectively. Moreover, the formula of angular distributions of their power radiation into the substrate is derived. Consider the effect of mass loading, the resistance density, defined as a scalar, is extended to generalized resistance densities which can be written as three 4 × 4 tensors and for which the formulas are derived. The bulk wave radiations for a synchronous one-port resonator on 42° Y-rotated LiTaO3 are simulated. It is found that the radiated energy by slow shear wave contributes a very high proportion to input electrical energy in some frequency range.

  8. Burnout current density of bismuth nanowires

    Science.gov (United States)

    Cornelius, T. W.; Picht, O.; Müller, S.; Neumann, R.; Völklein, F.; Karim, S.; Duan, J. L.

    2008-05-01

    Single bismuth nanowires with diameters ranging from 100nmto1μm were electrochemically deposited in ion track-etched single-pore polycarbonate membranes. The maximum current density the wires are able to carry was investigated by ramping up the current until failure occurred. It increases by three to four orders of magnitude for nanowires embedded in the template compared to bulk bismuth and rises with diminishing diameter. Simulations show that the wires are heated up electrically to the melting temperature. Since the surface-to-volume ratio rises with diminishing diameter, thinner wires dissipate the heat more efficiently to the surrounding polymer matrix and, thus, can tolerate larger current densities.

  9. Production, Properties and Applications of Bulk Amorphous Alloys

    Institute of Scientific and Technical Information of China (English)

    Tao Zhang; Akihisa Inoue

    2000-01-01

    A review is given of recent work concerned with the production method, the characteristic properties(1) Bulk amorphous system; (2) Mechanical and magnetic properties of bulkamorphous alloys; (3)application of bulk amorphous alloys.

  10. The relative density of lunar soil

    Science.gov (United States)

    Carrier, W. D., III; Mitchell, J. K.; Mahmood, A.

    1973-01-01

    The specific gravity and minimum and maximum bulk densities were determined for three one-gram lunar soil samples containing particles less than 1 mm in diameter: 14163,148; 14259,3; and 15601,82. The specific gravity varied from 2.90 to 2.93 for the Apollo 14 samples to 3.24 for the Apollo 15 sample. The difference is attributed to the higher proportion of agglutinates and breccias and fewer mineral fragments and basalts in the Apollo 14 soils. The minimum bulk densities varied from 0.87 to 1.10 g/cu cm, while the maximum densities varied from 1.51 to 1.89 g/cu cm. The ranges in values were due to differences in the specific gravity, re-entrant intragranular voids, particle shape, surface texture, and grain arrangements. The in situ lunar soil in the plains areas of the moon can have a low to medium relative density at the surface, increasing rapidly to a very high relative density at depths greater than 10 to 20 cm.

  11. Multi model approach to validate map based soil bulk density data using a lazy learning algorithm

    Science.gov (United States)

    The USDA-NRCS is partnering with other agencies to conduct a national scale assessment of environmental benefits and effects of 2002 Farm Bill programs. One of the components of the resulting Conservation Effects Assessment Project (CEAP) is a national-scale effort to estimate the on-site benefits o...

  12. Orbit and Bulk Density of the OSIRIS-REx Target Asteroid (101955) Bennu

    CERN Document Server

    Chesley, Steven R; Nolan, Michael C; Vokrouhlicky, David; Chodas, Paul W; Milani, Andrea; Spoto, Federica; Rozitis, Benjamin; Benner, Lance A M; Bottke, William F; Busch, Michael W; Emery, Joshua P; Howell, Ellen S; Lauretta, Dante S; Margot, Jean-Luc; Taylor, Patrick A

    2014-01-01

    The target asteroid of the OSIRIS-REx asteroid sample return mission, (101955) Bennu (formerly 1999 RQ$_{36}$), is a half-kilometer near-Earth asteroid with an extraordinarily well constrained orbit. An extensive data set of optical astrometry from 1999--2013 and high-quality radar delay measurements to Bennu in 1999, 2005, and 2011 reveal the action of the Yarkovsky effect, with a mean semimajor axis drift rate $da/dt = (-19.0 \\pm 0.1)\\times 10^{-4}$ au/Myr or $284\\pm 1.5\\;\\rm{m/yr}$. The accuracy of this result depends critically on the fidelity of the observational and dynamical model. As an example, neglecting the relativistic perturbations of the Earth during close approaches affects the orbit with $3\\sigma$ significance in $da/dt$. The orbital deviations from purely gravitational dynamics allow us to deduce the acceleration of the Yarkovsky effect, while the known physical characterization of Bennu allows us to independently model the force due to thermal emissions. The combination of these two analyses...

  13. Saturated hydraulic conductivity of US soils grouped according textural class and bulk density

    Science.gov (United States)

    Importance of the saturated hydraulic conductivity as soil hydraulic property led to the development of multiple pedotransfer functions for estimating it. One approach to estimating Ksat was using textural classes rather than specific textural fraction contents as pedotransfer inputs. The objective...

  14. Saturated hydraulic conductivity of US soils grouped according to textural class and bulk density

    Science.gov (United States)

    Importance of the saturated hydraulic conductivity as soil hydraulic property led to the development of multiple pedotransfer functions for estimating it. One approach to estimating Ksat was using textural classes rather than specific textural fraction contents as pedotransfer inputs. The objective...

  15. Effect of rare earth substitution in cobalt ferrite bulk materials

    Energy Technology Data Exchange (ETDEWEB)

    Bulai, G., E-mail: georgiana.bulai@uaic.ro [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I, nr. 11, 700506 Iasi (Romania); Diamandescu, L. [National Institute of Material Physics, P.O. Box MG-7, 07125 Bucharest (Romania); Dumitru, I.; Gurlui, S. [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I, nr. 11, 700506 Iasi (Romania); Feder, M. [National Institute of Material Physics, P.O. Box MG-7, 07125 Bucharest (Romania); Caltun, O.F. [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I, nr. 11, 700506 Iasi (Romania)

    2015-09-15

    The study was focused on the influence of small amounts of rare earth (RE=La, Ce, Sm, Gd, Dy, Ho, Er, Yb) addition on the microstructure, phase content and magnetic properties of cobalt ferrite bulk materials. The X-Ray diffraction measurements confirmed the formation of the spinel structure but also the presence of secondary phases of RE oxides or orthoferrite in small percentages (up to 3%). Density measurements obtained by Archimedes method revealed a ~1 g cm{sup −3} decrease for the RE doped cobalt ferrite samples compared with stoichiometric one. Both the Mössbauer and Fourier Transform Infrared Spectrocopy analysis results confirmed the formation of the spinel phase. The saturation magnetization and coercive field values of the doped samples obtained by Vibrating Sample Magnetometry were close to those of the pure cobalt ferrite. For magnetostrictive property studies the samples were analyzed using the strain gauge method. Higher maximum magnetostriction coefficients were found for the Ho, Ce, Sm and Yb doped cobalt ferrite bulk materials as related to the stoichiometric CoFe{sub 2}O{sub 4} sample. Moreover, improved strain derivative was observed for these samples but at higher magnetic fields due to the low increase of the coercive field values for doped samples. - Highlights: • Substitution by a large number of rare earth elements was investigated. • First reported results on magnetostriction measurements of RE doped cobalt ferrite. • The doped samples presented an increased porosity and a decreased grain size. • Increased magnetostrctive response was observed for several doped samples.

  16. Multi-octave supercontinuum generation from mid-infrared filamentation in a bulk crystal

    Directory of Open Access Journals (Sweden)

    Faccio D.

    2013-03-01

    Full Text Available We present supercontinuum generation pumped by femtosecond mid-infrared pulses in a bulk homogeneous material. The spectrum extends from 450 nm into the midinfrared, and carries high spectral energy density (3 pJ/nm–10 nJ/nm. The supercontinuum has high shot-to-shot reproducibility and preserves the carrier-to-envelope phase. Our result paves the way for compact supercontinuum sources with unprecedented bandwidth.

  17. DFT modelling of bulk-modulated carbon nanotube field-effect transistors

    OpenAIRE

    Latessa, L.; Pecchia, A.; Di Carlo, A.

    2005-01-01

    We report density-functional theory (DFT), atomistic simulations of the non-equilibrium transport properties of carbon nanotube (CNT) field-effect transistors (FETs). Results have been obtained within a self-consistent approach based on the non-equilibrium Green's functions (NEGF) scheme. Our attention has been focused on a new kind of devices, the so called bulk-modulated CNTFETs. Recent experimental realizations \\cite{Chen,Lin_condMat} have shown that such devices can exhibit excellent perf...

  18. Polymerization of vinyl acetate in bulk and emulsion by gamma irradiation

    Science.gov (United States)

    Mesquita, Andrea C.; Mori, Manoel N.; Andrade e Silva, Leonardo G.

    2004-09-01

    The vinyl acetate polymerization to produce poly(vinyl acetate) was carried out in bulk and emulsion using a 60Co gamma irradiator Gammacell-220 type. The irradiation was carried out in a dose rate of 5.25 and 5.30 kGy/h, respectively. The polymers obtained were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC) and gel permeation chromatography (GPC). Tests of density, hardness and Vicat softening temperature were carried out.

  19. Constructing local bulk observables in interacting AdS/CFT

    CERN Document Server

    Kabat, Daniel; Lowe, David A

    2011-01-01

    Local operators in the bulk of AdS can be represented as smeared operators in the dual CFT. We show how to construct these bulk observables by requiring that the bulk operators commute at spacelike separation. This extends our previous work by taking interactions into account. Large-N factorization plays a key role in the construction. We show diagrammatically how this procedure is related to bulk Feynman diagrams.

  20. Substantial bulk photovoltaic effect enhancement via nanolayering.

    Science.gov (United States)

    Wang, Fenggong; Young, Steve M; Zheng, Fan; Grinberg, Ilya; Rappe, Andrew M

    2016-01-21

    Spontaneous polarization and inversion symmetry breaking in ferroelectric materials lead to their use as photovoltaic devices. However, further advancement of their applications are hindered by the paucity of ways of reducing bandgaps and enhancing photocurrent. By unravelling the correlation between ferroelectric materials' responses to solar irradiation and their local structure and electric polarization landscapes, here we show from first principles that substantial bulk photovoltaic effect enhancement can be achieved by nanolayering PbTiO3 with nickel ions and oxygen vacancies ((PbNiO2)x(PbTiO3)(1-x)). The enhancement of the total photocurrent for different spacings between the Ni-containing layers can be as high as 43 times due to a smaller bandgap and photocurrent direction alignment for all absorption energies. This is due to the electrostatic effect that arises from nanolayering. This opens up the possibility for control of the bulk photovoltaic effect in ferroelectric materials by nanoscale engineering of their structure and composition.

  1. Enhancing bulk superconductivity by engineering granular materials

    Science.gov (United States)

    Mayoh, James; García García, Antonio

    2014-03-01

    The quest for higher critical temperatures is one of the main driving forces in the field of superconductivity. Recent theoretical and experimental results indicate that quantum size effects in isolated nano-grains can boost superconductivity with respect to the bulk limit. Here we explore the optimal range of parameters that lead to an enhancement of the critical temperature in a large three dimensional array of these superconducting nano-grains by combining mean-field, semiclassical and percolation techniques. We identify a broad range of parameters for which the array critical temperature, TcArray, can be up to a few times greater than the non-granular bulk limit, Tc 0. This prediction, valid only for conventional superconductors, takes into account an experimentally realistic distribution of grain sizes in the array, charging effects, dissipation by quasiparticles and limitations related to the proliferation of thermal fluctuations for sufficiently small grains. For small resistances we find the transition is percolation driven. Whereas at larger resistances the transition occurs above the percolation threshold due to phase fluctuations. JM acknowledes support from an EPSRC Ph.D studentship, AMG acknowledges support from EPSRC, grant No. EP/I004637/1, FCT, grant PTDC/FIS/111348/2009 and a Marie Curie International Reintegration Grant PIRG07-GA-2010-268172.

  2. Substantial bulk photovoltaic effect enhancement via nanolayering

    Science.gov (United States)

    Wang, Fenggong; Young, Steve M.; Zheng, Fan; Grinberg, Ilya; Rappe, Andrew M.

    2016-01-01

    Spontaneous polarization and inversion symmetry breaking in ferroelectric materials lead to their use as photovoltaic devices. However, further advancement of their applications are hindered by the paucity of ways of reducing bandgaps and enhancing photocurrent. By unravelling the correlation between ferroelectric materials' responses to solar irradiation and their local structure and electric polarization landscapes, here we show from first principles that substantial bulk photovoltaic effect enhancement can be achieved by nanolayering PbTiO3 with nickel ions and oxygen vacancies ((PbNiO2)x(PbTiO3)1-x). The enhancement of the total photocurrent for different spacings between the Ni-containing layers can be as high as 43 times due to a smaller bandgap and photocurrent direction alignment for all absorption energies. This is due to the electrostatic effect that arises from nanolayering. This opens up the possibility for control of the bulk photovoltaic effect in ferroelectric materials by nanoscale engineering of their structure and composition.

  3. Ideal bulk pressure of active Brownian particles

    Science.gov (United States)

    Speck, Thomas; Jack, Robert L.

    2016-06-01

    The extent to which active matter might be described by effective equilibrium concepts like temperature and pressure is currently being discussed intensely. Here, we study the simplest model, an ideal gas of noninteracting active Brownian particles. While the mechanical pressure exerted onto confining walls has been linked to correlations between particles' positions and their orientations, we show that these correlations are entirely controlled by boundary effects. We also consider a definition of local pressure, which describes interparticle forces in terms of momentum exchange between different regions of the system. We present three pieces of analytical evidence which indicate that such a local pressure exists, and we show that its bulk value differs from the mechanical pressure exerted on the walls of the system. We attribute this difference to the fact that the local pressure in the bulk does not depend on boundary effects, contrary to the mechanical pressure. We carefully examine these boundary effects using a channel geometry, and we show a virial formula for the pressure correctly predicts the mechanical pressure even in finite channels. However, this result no longer holds in more complex geometries, as exemplified for a channel that includes circular obstacles.

  4. Characterization of bulk superconductors through EBSD methods

    Science.gov (United States)

    Koblischka, M. R.; Koblischka-Veneva, A.

    2003-10-01

    The application of electron backscatter diffraction (EBSD) technique to bulk high- Tc superconductors is presented and reviewed. Due to the ceramic nature and the complex crystallographic unit cells of the perovskite-type high- Tc superconductors, the EBSD analysis is not yet as common as it deserves. We have successfully performed EBSD analysis on a variety of high- Tc compounds and samples including polycrystalline YBCO (pure and doped by alkali metals), melt-textured YBCO, thin and thick films of YBCO; the “green phase” Y 2BaCuO 5, thin film and melt-textured NdBa 2Cu 3O x and Bi-2212 single crystals and tapes. It is shown that the surface preparation of the samples is crucial due to the small information depth (up to 100 nm) of the EBSD technique. High quality Kikuchi patterns are the requirement in order to enable the automated EBSD mapping, which yields phase distributions, individual grain orientations and the misorientation angle distribution. The results can be presented in form of mappings, as charts, and as pole figures. These informations are required for a better understanding of the growth mechanism(s) of bulk high- Tc superconductors intended for applications.

  5. Substantial bulk photovoltaic effect enhancement via nanolayering.

    Science.gov (United States)

    Wang, Fenggong; Young, Steve M; Zheng, Fan; Grinberg, Ilya; Rappe, Andrew M

    2016-01-01

    Spontaneous polarization and inversion symmetry breaking in ferroelectric materials lead to their use as photovoltaic devices. However, further advancement of their applications are hindered by the paucity of ways of reducing bandgaps and enhancing photocurrent. By unravelling the correlation between ferroelectric materials' responses to solar irradiation and their local structure and electric polarization landscapes, here we show from first principles that substantial bulk photovoltaic effect enhancement can be achieved by nanolayering PbTiO3 with nickel ions and oxygen vacancies ((PbNiO2)x(PbTiO3)(1-x)). The enhancement of the total photocurrent for different spacings between the Ni-containing layers can be as high as 43 times due to a smaller bandgap and photocurrent direction alignment for all absorption energies. This is due to the electrostatic effect that arises from nanolayering. This opens up the possibility for control of the bulk photovoltaic effect in ferroelectric materials by nanoscale engineering of their structure and composition. PMID:26791545

  6. 7 CFR 58.313 - Print and bulk packaging rooms.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Print and bulk packaging rooms. 58.313 Section 58.313 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....313 Print and bulk packaging rooms. Rooms used for packaging print or bulk butter and related...

  7. 19 CFR 151.24 - Unlading facilities for bulk sugar.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Unlading facilities for bulk sugar. 151.24 Section... OF THE TREASURY (CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Sugars, Sirups, and Molasses § 151.24 Unlading facilities for bulk sugar. When dutiable sugar is to be imported in bulk, a...

  8. 30 CFR 56.6802 - Bulk delivery vehicles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bulk delivery vehicles. 56.6802 Section 56.6802... § 56.6802 Bulk delivery vehicles. No welding or cutting shall be performed on a bulk delivery vehicle until the vehicle has been washed down and all explosive material has been removed. Before welding...

  9. 30 CFR 57.6802 - Bulk delivery vehicles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bulk delivery vehicles. 57.6802 Section 57.6802...-Surface and Underground § 57.6802 Bulk delivery vehicles. No welding or cutting shall be performed on a bulk delivery vehicle until the vehicle has been washed down and all explosive material has...

  10. Demonstration of a silicon photomultiplier with bulk integrated quenching resistors on epitaxial silicon

    International Nuclear Information System (INIS)

    In this paper we present the experimental results of a silicon photomultiplier (SiPM) with bulk integrated quenching resistors on epitaxial silicon. Compared with existing SiPM with polysilicon quenching resistors on the surface or with MRS structure, it has potential advantages of high photon detection efficiency (PDE) while retaining a large micro-cell density and the fabrication process is also simplified. The SiPM with the micro-cell density up to 104/mm2 and the PDE up to 25.6% is demonstrated. The characteristics of dark count rate, single photon detection capability, gain, optical crosstalk and PDE have been investigated and discussed.

  11. Role of van der Waals bonding in layered oxide: Bulk vanadium pentoxide

    OpenAIRE

    Londero, Elisa; Schroder, Elsebeth

    2010-01-01

    Sparse matter is characterized by regions with low electron density and its understanding calls for methods to accurately calculate both the van der Waals (vdW) interactions and other bonding. Here we present a first-principles density functional theory (DFT) study of a layered oxide (V2O5) bulk structure which shows charge voids in between the layers and we highlight the role of the vdW forces in building up material cohesion. The result of previous first-principles studies involving semiloc...

  12. Bianchi type-VIh string cloud cosmological models with bulk viscosity

    Science.gov (United States)

    Tripathy, Sunil K.; Behera, Dipanjali

    2010-11-01

    String cloud cosmological models are studied using spatially homogeneous and anisotropic Bianchi type VIh metric in the frame work of general relativity. The field equations are solved for massive string cloud in presence of bulk viscosity. A general linear equation of state of the cosmic string tension density with the proper energy density of the universe is considered. The physical and kinematical properties of the models have been discussed in detail and the limits of the anisotropic parameter responsible for different phases of the universe are explored.

  13. Composition mediated serration dynamics in Zr-based bulk metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.; Qiao, J. W., E-mail: qiaojunwei@gmail.com, E-mail: mwchen@wpi-aimr.tohoku.ac.jp; Wang, B. C.; Xu, B. S. [Laboratory of Applied Physics and Mechanics of Advanced Materials, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Tian, H. [College of Computer Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Sun, B. A. [Center for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon Tong, Kowloon (Hong Kong); Chen, M. W., E-mail: qiaojunwei@gmail.com, E-mail: mwchen@wpi-aimr.tohoku.ac.jp [Laboratory of Applied Physics and Mechanics of Advanced Materials, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

    2015-11-16

    The composition mediated serration dynamics in Zr-based bulk metallic glasses (BMGs) is investigated by statistics analyses of the elastic-energy density, and free volumes during shear-banding are beneficial to understand serrated-flow behavior. The amplitude and elastic-energy density display a gradually increasing and then decreasing trend with increasing the content of Zr. It is based on the free-volume theory describing the atomic-level structure of ternary Zr-Cu-Al BMGs. The good agreement between the molecular dynamics simulation and experimental results provides evidence for the variation of free volumes as the elementary mechanism of composition mediated serration dynamics.

  14. Correspondence between Experiment and Theory of Bulk Electrocrystallisation at Solid Electrodes in Aqueous Electrolyte

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    A theory of bulk-metal electrocrystallisation at solid-metal surfaces in aqueous electrolytes is presented. The electrochemical processes in the vicinity of the electrode surface are dynamic interactions between charged and uncharged species. Redox processes in the classical sense constitute only...... position relative to the electrode, the rate of reduction and oxidation may increase thus leading to current densities that exceed the magnitude of conventional diffusion current densities observed in cyclic voltammetry. This result was accomplished by including in the description a depletion layer devoid...

  15. Bulk forming of industrial micro components in conventional metals and bulk metallic glasses

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Paldan, Nikolas Aulin; Eriksen, Rasmus Solmer;

    2007-01-01

    For production of micro components in large numbers, forging is an interesting and challenging process. The conventional metals like silver, steel and aluminum often require multi-step processes, but high productivity and increased strength justify the investment. As an alternative, bulk metallic...

  16. Properties of grain boundaries in bulk, melt processed Y–Ba–Cu–O fabricated using bridge-shaped seeds

    International Nuclear Information System (INIS)

    Single grain RE–Ba–Cu–O ((RE)BCO, where RE is a rare earth element or yttrium) bulk superconducting materials have significant potential for a variety of engineering applications due to their ability to trap high magnetic fields. However, it is well known that the presence of grain boundaries coupled with a high angle of misorientation (typically 5°) significantly reduces the critical current density, Jc, in all forms of high temperature superconducting materials. It is of considerable fundamental and technological interest, therefore, to investigate the grain boundary properties of bulk, film and tape (RE)BCO. We report a successful multi-seeding technique for the fabrication of fully aligned, artificial (0° misalignment) grain boundaries within large grain YBCO bulk superconductors using bridge-shaped seeds. The microstructure and critical current densities of the grain boundaries produced by this technique have been studied in detail. (paper)

  17. Properties of grain boundaries in bulk, melt processed Y-Ba-Cu-O fabricated using bridge-shaped seeds

    Science.gov (United States)

    Shi, Y.-H.; Durrell, J. H.; Dennis, A. R.; Babu, N. Hari; Mancini, C. E.; Cardwell, D. A.

    2012-04-01

    Single grain RE-Ba-Cu-O ((RE)BCO, where RE is a rare earth element or yttrium) bulk superconducting materials have significant potential for a variety of engineering applications due to their ability to trap high magnetic fields. However, it is well known that the presence of grain boundaries coupled with a high angle of misorientation (typically 5°) significantly reduces the critical current density, Jc, in all forms of high temperature superconducting materials. It is of considerable fundamental and technological interest, therefore, to investigate the grain boundary properties of bulk, film and tape (RE)BCO. We report a successful multi-seeding technique for the fabrication of fully aligned, artificial (0° misalignment) grain boundaries within large grain YBCO bulk superconductors using bridge-shaped seeds. The microstructure and critical current densities of the grain boundaries produced by this technique have been studied in detail.

  18. First-principles study of optical properties of α-CuSe/klockmannite: Bulk and nano-layers

    Energy Technology Data Exchange (ETDEWEB)

    Shojaei, Ali Reza, E-mail: Ali.r.shojaei@gmail.com [Department of Physics, Lenjan Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Faculty of Science, Physics Department, University of Isfahan, 81746-73441 Isfahan (Iran, Islamic Republic of); Vaez, Aminollah; Nourbakhsh, Zahra; Madaniyan, Zeynab Sadat [Faculty of Science, Physics Department, University of Isfahan, 81746-73441 Isfahan (Iran, Islamic Republic of)

    2014-04-01

    The optical properties of α-CuSe bulk and its nano-layers (NLs) have been studied by the first principles theoretical study in the framework of density functional theory. These properties are calculated with regard to dielectric function, refractive index, extinction coefficient, reflection coefficient, absorption coefficient, energy-loss function, and optical conductivity. To create NLs, two different thicknesses through CuSe bulk are chosen in the (0001) direction as the first and second thicknesses. The former thickness is divided into six different NLs with variant alternations. These NLs have the same chemical composition and are structural isomers. Among the NLs, the optical properties of the most stable NL and its double thickness are calculated and compared with the bulk state. The imaginary part of dielectric function has a main peak at low energies because α-CuSe is a conductive compound in the bulk state. The electronic structure of NLs shows that they have remained conductive in x (or y) direction, but they interestingly have a dielectric behavior with an ultra-low electrical conductivity in z direction. The optical curves in the bulk and NLs show the anisotropic feature between x and z directions. In the range of infrared to red light, the bulk refractive index, n{sub z}(ω), is very large, about 6, while n{sub x}(ω) is about 3. Results show that the NLs have wide absorption curves in the range of solar spectrum from infrared to ultraviolet. - Highlights: • Optical properties of α-CuSe bulk and its nano-layers (NLs) are studied • Our calculations are performed within framework of Density functional theory using full potential method. • The NLs stabilities and thickness effect on their optical properties are discussed. • Bulk and NLs optical curves show anisotropic feature between x (or y) and z directions. • NLs showed conductivity in x (or y) direction but ultra-low conductivity in z direction.

  19. Bulk semiconducting scintillator device for radiation detection

    Energy Technology Data Exchange (ETDEWEB)

    Stowe, Ashley C.; Burger, Arnold; Groza, Michael

    2016-08-30

    A bulk semiconducting scintillator device, including: a Li-containing semiconductor compound of general composition Li-III-VI.sub.2, wherein III is a Group III element and VI is a Group VI element; wherein the Li-containing semiconductor compound is used in one or more of a first mode and a second mode, wherein: in the first mode, the Li-containing semiconductor compound is coupled to an electrical circuit under bias operable for measuring electron-hole pairs in the Li-containing semiconductor compound in the presence of neutrons and the Li-containing semiconductor compound is also coupled to current detection electronics operable for detecting a corresponding current in the Li-containing semiconductor compound; and, in the second mode, the Li-containing semiconductor compound is coupled to a photodetector operable for detecting photons generated in the Li-containing semiconductor compound in the presence of the neutrons.

  20. Bulk disk resonator based ultrasensitive mass sensor

    DEFF Research Database (Denmark)

    Cagliani, Alberto; Davis, Zachary James

    2009-01-01

    In the framework of developing an innovative label-free sensor for multiarrayed biodetection applications, we present a novel bulk resonator based mass sensor. The sensor is a polysilicon disk which shows a Q-factor of 6400 in air at 68.8 MHz, resulting in mass resolutions down in the femtogram...... range. The sensor has been characterized in terms of sensitivity both for distributed mass detection, performing six consecutive depositions of e-beam evaporated Au, and localized mass detection, depositing approximately 7.5 pg of Pt/Ga/C three times consecutively with a Focused Ion Beam system....... The sensor has an extremely high distributed mass to frequency shift sensitivity of 60104 Hzcm2/¿g and shows a localized mass to frequency sensitivity up to 4405 Hz/pg with a localized mass resolution down to 15 fg. The device has been fabricated with a new microfabrication process that uses only two...

  1. Tuneable film bulk acoustic wave resonators

    CERN Document Server

    Gevorgian, Spartak Sh; Vorobiev, Andrei K

    2013-01-01

    To handle many standards and ever increasing bandwidth requirements, large number of filters and switches are used in transceivers of modern wireless communications systems. It makes the cost, performance, form factor, and power consumption of these systems, including cellular phones, critical issues. At present, the fixed frequency filter banks based on Film Bulk Acoustic Resonators (FBAR) are regarded as one of the most promising technologies to address performance -form factor-cost issues. Even though the FBARs improve the overall performances the complexity of these systems remains high.  Attempts are being made to exclude some of the filters by bringing the digital signal processing (including channel selection) as close to the antennas as possible. However handling the increased interference levels is unrealistic for low-cost battery operated radios. Replacing fixed frequency filter banks by one tuneable filter is the most desired and widely considered scenario. As an example, development of the softwa...

  2. Holographic bulk viscosity: GPR vs EO

    CERN Document Server

    Buchel, Alex; Kiritsis, Elias

    2011-01-01

    Recently Eling and Oz (EO) proposed a formula for the holographic bulk viscosity, in arXiv:1103.1657, derived from the null horizon focusing equation. This formula seems different from that obtained earlier by Gubser, Pufu and Rocha (GPR) in arXiv:0806.0407 calculated from the IR limit of the two-point function of the trace of the stress tensor. The two were shown to agree only for some simple scaling cases. We point out that the two formulae agree in two non-trivial holographic theories describing RG flows. The first is the strongly coupled N=2* gauge theory plasma. The second is the semi-phenomenological model of Improved Holographic QCD.

  3. Universe Models with Negative Bulk Viscosity

    CERN Document Server

    Brevik, Iver

    2013-01-01

    The concept of negative temperatures has occasionally been used in connection with quantum systems. A recent example of this sort is reported in the paper of S. Braun et al. [Science 339,52 (2013)], where an attractively interacting ensemble of ultracold atoms is investigated experimentally and found to correspond to a negative-temperature system since the entropy decreases with increasing energy at the high end of the energy spectrum. As the authors suggest, it would be of interest to investigate whether a suitable generalization of standard cosmological theory could be helpful, in order to elucidate the observed accelerated expansion of the universe usually explained in terms of a positive tensile stress (negative pressure). In the present note we take up this basic idea and investigate a generalization of the standard viscous cosmological theory, not by admitting negative temperatures but instead by letting the bulk viscosity take negative values. Evidently, such an approach breaks standard thermodynamics,...

  4. Forming of bulk metallic glass microcomponents

    DEFF Research Database (Denmark)

    Wert, John A.; Thomsen, Christian; Jensen, Rune Debel;

    2009-01-01

    The present article considers forward extrusion, closed-die forging and backward extrusion processes for fabrication of individual microcomponents from two bulk metallic glass (BMG) compositions: Mg60Cu30Y10 and Zr44Cu40Ag8Al8. Two types of tooling were used in the present work: relatively massive...... die sets characteristic of cold forming operations for crystalline metals and lightweight die sets adapted to the special characteristics of BMGs. In addition to demonstrating that microcomponents of several geometries can be readily fabricated from BMGs, rheological properties are combined...... with crystallization kinetics to formulate a generally applicable method that can guide selection of optimal forming parameters. Finally, the use of particulate-based lubricants for BMG forming is shown to result in individual lubricant particles becoming mechanically locked into the BMG surface. (C) 2008 Elsevier B...

  5. Vortices in superconducting bulk, films and SQUIDs

    Indian Academy of Sciences (India)

    Ernst Helmut Brandt

    2006-01-01

    The properties of the ideal periodic vortex lattice in bulk superconductors and in films of any thickness can be calculated from Ginzburg-Landau theory by an iteration method using Fourier series. The London theory yields general analytic expressions for the magnetic field and energy of arbitrary arrangements of straight or curved vortex lines. The elasticity of the vortex lattice is highly nonlocal. The magnetic response of superconductors of realistic shapes like thin and thick strips and disks or thin rectangular plates or films, containing pinned vortices, can be computed within continuum theory by solving an integral equation. A useful example is a thin square with a central hole and a radial slit, used as superconducting quantum interference device (SQUID).

  6. Contact characteristics for YBCO bulk superconductors

    Science.gov (United States)

    Yamamoto, Naoki; Sakai, Tomokazu; Sawa, Koichiro; Tomita, Masaru; Murakami, Masato

    2003-10-01

    We have studied the contact characteristics of two resin-impregnated YBCO (a composite of YBa 2Cu 3O y and Y 2BaCuO 5) bulk superconductors in mechanical contact. A switching phenomenon could be observed at a threshold current or a transfer current value in the V- I curves of the YBCO contact. The transfer current exceeded the previous value of 13.5 A at 77 K in the contact when the sample surfaces were carefully polished. The present results suggest that a pair of YBCO blocks might be applicable to the mechanical persistent current switch for superconducting magnetic energy storage and other superconducting systems run in a persistent current mode.

  7. DEPLOYMENT OF THE BULK TRITIUM SHIPPING PACKAGE

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, P.

    2013-10-10

    A new Bulk Tritium Shipping Package (BTSP) was designed by the Savannah River National Laboratory to be a replacement for a package that has been used to ship tritium in a variety of content configurations and forms since the early 1970s. The BTSP was certified by the National Nuclear Safety Administration in 2011 for shipments of up to 150 grams of Tritium. Thirty packages were procured and are being delivered to various DOE sites for operational use. This paper summarizes the design features of the BTSP, as well as associated engineered material improvements. Fabrication challenges encountered during production are discussed as well as fielding requirements. Current approved tritium content forms (gas and tritium hydrides), are reviewed, as well as, a new content, tritium contaminated water on molecular sieves. Issues associated with gas generation will also be discussed.

  8. Diffusion and bulk flow in phloem loading

    DEFF Research Database (Denmark)

    Dölger, Julia; Rademaker, Hanna; Liesche, Johannes;

    2014-01-01

    %-20% to the sucrose flux into the intermediary cells, while the main part is transported by diffusion. On the other hand, the subsequent sugar translocation into the sieve elements would very likely be carried predominantly by bulk water flow through the plasmodesmata. Thus, in contrast to apoplasmic loaders, all......Plants create sugar in the mesophyll cells of their leaves by photosynthesis. This sugar, mostly sucrose, has to be loaded via the bundle sheath into the phloem vascular system (the sieve elements), where it is distributed to growing parts of the plant. We analyze the feasibility of a particular...... loading mechanism, active symplasmic loading, also called the polymer trap mechanism, where sucrose is transformed into heavier sugars, such as raffinose and stachyose, in the intermediary-type companion cells bordering the sieve elements in the minor veins of the phloem. Keeping the heavier sugars from...

  9. Combustion of bulk titanium in oxygen

    Science.gov (United States)

    Clark, A. F.; Moulder, J. C.; Runyan, C. C.

    1975-01-01

    The combustion of bulk titanium in one atmosphere oxygen is studied using laser ignition and several analytical techniques. These were high-speed color cinematography, time and space resolved spectra in the visible region, metallography (including SEM) of specimens quenched in argon gas, X-ray and chemical product analyses, and a new optical technique, the Hilbert transform method. The cinematographic application of this technique for visualizing phase objects in the combustion zone is described. The results indicate an initial vapor phase reaction immediately adjacent to the molten surface but as the oxygen uptake progresses the evaporation approaches the point of congruency and a much reduced evaporation rate. This and the accumulation of the various soluble oxides soon drive the reaction zone below the surface where gas formation causes boiling and ejection of particles. The buildup of rutile cuts off the oxygen supply and the reaction ceases.

  10. Density Estimations in Laboratory Debris Flow Experiments

    Science.gov (United States)

    Queiroz de Oliveira, Gustavo; Kulisch, Helmut; Malcherek, Andreas; Fischer, Jan-Thomas; Pudasaini, Shiva P.

    2016-04-01

    Bulk density and its variation is an important physical quantity to estimate the solid-liquid fractions in two-phase debris flows. Here we present mass and flow depth measurements for experiments performed in a large-scale laboratory set up. Once the mixture is released and it moves down the inclined channel, measurements allow us to determine the bulk density evolution throughout the debris flow. Flow depths are determined by ultrasonic pulse reflection, and the mass is measured with a total normal force sensor. The data were obtained at 50 Hz. The initial two phase material was composed of 350 kg debris with water content of 40%. A very fine pebble with mean particle diameter of 3 mm, particle density of 2760 kg/m³ and bulk density of 1400 kg/m³ in dry condition was chosen as the solid material. Measurements reveal that the debris bulk density remains high from the head to the middle of the debris body whereas it drops substantially at the tail. This indicates lower water content at the tail, compared to the head and the middle portion of the debris body. This means that the solid and fluid fractions are varying strongly in a non-linear manner along the flow path, and from the head to the tail of the debris mass. Importantly, this spatial-temporal density variation plays a crucial role in determining the impact forces associated with the dynamics of the flow. Our setup allows for investigating different two phase material compositions, including large fluid fractions, with high resolutions. The considered experimental set up may enable us to transfer the observed phenomena to natural large-scale events. Furthermore, the measurement data allows evaluating results of numerical two-phase mass flow simulations. These experiments are parts of the project avaflow.org that intends to develop a GIS-based open source computational tool to describe wide spectrum of rapid geophysical mass flows, including avalanches and real two-phase debris flows down complex natural

  11. Laboratory Density Functionals

    OpenAIRE

    Giraud, B. G.

    2007-01-01

    We compare several definitions of the density of a self-bound system, such as a nucleus, in relation with its center-of-mass zero-point motion. A trivial deconvolution relates the internal density to the density defined in the laboratory frame. This result is useful for the practical definition of density functionals.

  12. Spin-enhanced organic bulk heterojunction photovoltaic solar cells.

    Science.gov (United States)

    Zhang, Ye; Basel, Tek P; Gautam, Bhoj R; Yang, Xiaomei; Mascaro, Debra J; Liu, Feng; Vardeny, Z Valy

    2012-01-01

    Recently, much effort has been devoted to improve the efficiency of organic photovoltaic solar cells based on blends of donors and acceptors molecules in bulk heterojunction architecture. One of the major losses in organic photovoltaic devices has been recombination of polaron pairs at the donor-acceptor domain interfaces. Here, we present a novel method to suppress polaron pair recombination at the donor-acceptor domain interfaces and thus improve the organic photovoltaic solar cell efficiency, by doping the device active layer with spin 1/2 radical galvinoxyl. At an optimal doping level of 3 wt%, the efficiency of a standard poly(3-hexylthiophene)/1-(3-(methoxycarbonyl)propyl)-1-1-phenyl)(6,6)C(61) solar cell improves by 18%. A spin-flip mechanism is proposed and supported by magneto-photocurrent measurements, as well as by density functional theory calculations in which polaron pair recombination rate is suppressed by resonant exchange interaction between the spin 1/2 radicals and charged acceptors, which convert the polaron pair spin state from singlet to triplet.

  13. An inexpensive sampler for obtaining bulk sediment cores

    Science.gov (United States)

    Cooper, Charles M.; Schiebe, Frank R.; Ritchie, Jerry C.

    1991-09-01

    A large-volume core sampler for sediment—muck substrates is described. The sampler can acquire a discrete sediment core of 10 cm in diameter and up to 1.5 m long. Such samplers are needed to collect the volume necessary for analysis of sediments for contaminants, bulk density, or radioactive dating. The sampler consists of a 1- to 2-m length of PVC pipe mounted below a threaded metal pipe air exhaust—intake assembly. This assembly is quick-connected to standard threaded lengths (300 cm) of water pipe (2 cm diam) or electrical conduit so that bottom sediments in water depths of up to 10 m can be sampled. The core sampler is hand-operated and pushed into bottom sediments from a boat. It does not have to be triggered remotely because of the one-way modified check valve in the air exhaust—intake assembly. After the sampler is extracted from the sediment, the extension handle can be quickly removed for ease of sampler handling, and the core can be extruded from the PVC tube by air pressure.

  14. Simulation of Singlet Exciton Diffusion in Bulk Organic Materials.

    Science.gov (United States)

    Kranz, Julian J; Elstner, Marcus

    2016-09-13

    We present a scheme for nonadiabatic direct dynamics simulation of Frenkel exciton diffusion in bulk molecular systems. The fluctuations of exciton couplings caused by the molecular motion can crucially influence exciton transport in such materials. This effect can be conveniently taken into account by computing the exciton couplings along molecular dynamics trajectories, as shown recently. In this work, we combine Molecular Dynamics simulations with a Frenkel Hamiltonian into a combined quantum-mechanical/molecular mechanics approach in order to allow for a simultaneous propagation of nuclear and electronic degrees of freedom using nonadiabatic dynamics propagation schemes. To reach the necessary time and length scales, we use classical force-fields and the semiempirical time-dependent density functional tight-binding method in combination with a fragmentation of the electronic structure. Fewest-switches surface-hopping, with adaptions to handle trivial crossings, and the Boltzmann-corrected Ehrenfest method are used to follow the excitonic quantum dynamics according to the classical evolution of the nuclei. As an application, we present the simulation of singlet exciton diffusion in crystalline anthracene, which allows us to address strengths and shortcomings of the presented methodology in detail. PMID:27434173

  15. The dynamic crossover in water does not require bulk water.

    Science.gov (United States)

    Turton, David A; Corsaro, Carmelo; Martin, David F; Mallamace, Francesco; Wynne, Klaas

    2012-06-14

    Many of the anomalous properties of water may be explained by invoking a second critical point that terminates the coexistence line between the low- and high-density amorphous states in the liquid. Direct experimental evidence of this point, and the associated polyamorphic liquid-liquid transition, is elusive as it is necessary for liquid water to be cooled below its homogeneous-nucleation temperature. To avoid crystallization, water in the eutectic LiCl solution has been studied but then it is generally considered that "bulk" water cannot be present. However, recent computational and experimental studies observe cooperative hydration in which case it is possible that sufficient hydrogen-bonded water is present for the essential characteristics of water to be preserved. For femtosecond optical Kerr-effect and nuclear magnetic resonance measurements, we observe in each case a fractional Stokes-Einstein relation with evidence of the dynamic crossover appearing near 220 K and 250 K respectively. Spectra obtained in the glass state also confirm the complex nature of the hydrogen-bonding modes reported for neat room-temperature water and support predictions of anomalous diffusion due to "worm-hole" structure.

  16. Near-Earth bursty bulk flows and AE index

    Institute of Scientific and Technical Information of China (English)

    ZHANG LingQian; SHI JianKui; LIU ZhenXing; W BAUMJOHANN; MA ZhiWei; M. W. DUNLOP; C. CARR; H. REME

    2008-01-01

    With the 4-s resolution data of the magnetometer and the ion plasma analyzer on TC-1 from June to November of each year during the period of 2004-2006, we statistically analyzed the occurrence rate of both convective and field-aligned bursty flows (FABFs). A near-Earth bursty bulk flow (NEBBF) occurred during both the quiet time and substorm process. In general, the magnetic field and the plasma density began oscillating with the appearance of the NEBBF associated with a distinct increase of the AE index. The increase of AE index during the NEBBF was more than 100 nT in both quiet time and substorm process. The statistical analysis indicated that the occurrence rates of the FABFs were nearly the same in the dif-ferent stages of the AE index, but the occurrence rate of the NEBBFs was much higher in the growth stage of the AE index, indicating that the NEBBFs were di-rectly related to the growth and expansion phases of the substorm. The observa-tions suggested that the quite large number of BBFs from the mid magnetotail could enter into the near-Earth tail and play important role in triggering the sub-storm onset.

  17. Performance and applications of quench melt-growth bulk magnets

    Science.gov (United States)

    Nariki, S.; Teshima, H.; Morita, M.

    2016-03-01

    This paper describes the progress in quench melt-growth (QMG) bulk magnets, developed by the Nippon Steel & Sumitomo Metal Corporation, which consist of single crystalline RE123 phase and finely dispersed RE211 particles. QMG bulks can trap high magnetic fields. The field-trapping ability of QMG bulks is largely increased with an improvement in its J c and size, promising the realization of various applications such as flywheel energy-storage systems, ship motors, NMR/MRI spectrometers, wind-power generators and so on. Intensive research has revealed that the optimal RE element is different depending on application requirements. Gd-QMG bulk is the most promising material for several high-field engineering applications. The trapped magnetic field of Gd-QMG bulk 60 mm in diameter at 77 K is twice as large as that of Y-QMG bulk with a similar size due to its excellent J c properties. The large Gd-based QMG bulks up to 150 mm in diameter are fabricated by incorporating the RE compositional gradient method. Compact NMR/MRI spectrometers are one of the promising applications of bulk superconductors. Eu-QMG bulks are suitable for NMR magnets. NMR applications require extremely homogeneous magnetic fields. In the Eu-system, the small paramagnetic moment of a Eu ion compared to a Gd ion improves the field homogeneity in the bulk. For the application of current leads, Dy-based QMG is available by utilizing a low thermal conductivity.

  18. The preliminary studies on preparation and characterization of bulk nanoporous zinc as a laser target candidate to generate soft x-ray

    Directory of Open Access Journals (Sweden)

    Mohd Lutfi Ahmad Shahar

    2012-12-01

    Full Text Available Bulk nanoporous metal has become a reliable source to replace liquid as source to generate EUV lithography which have debris problem to tackle. A solid yet low density porous material promised a low melting point and low plasma density. The plasma density of bulk nanoporous Sn and SnO2 profile plays a key role in the generation of 13.5 nm light for an extreme ultraviolet lithography (EUVL source from laser produced plasma (LPP. The success of this preparation method might solve problems related to EUV lithography, or even soft Xray (XUV lithography. In this paper, we present the preliminary result of preparing such ideal low density target in form of bulk metal porous.

  19. Nuclear Energy Density Functionals: What do we really know?

    CERN Document Server

    Bulgac, Aurel; Jin, Shi

    2015-01-01

    We present the simplest nuclear energy density functional (NEDF) to date, determined by only 4 significant phenomenological parameters, yet capable of fitting measured nuclear masses with better accuracy than the Bethe-Weizs\\"acker mass formula, while also describing density structures (charge radii, neutron skins etc.) and time-dependent phenomena (induced fission, giant resonances, low energy nuclear collisions, etc.). The 4 significant parameters are necessary to describe bulk nuclear properties (binding energies and charge radii); an additional 2 to 3 parameters have little influence on the bulk nuclear properties, but allow independent control of the density dependence of the symmetry energy and isovector excitations, in particular the Thomas-Reiche-Kuhn sum rule. This Hohenberg-Kohn-style of density functional theory successfully realizes Weizs\\"acker's ideas and provides a computationally tractable model for a variety of static nuclear properties and dynamics, from finite nuclei to neutron stars, where...

  20. Thermal properties measurement of dry bulk materials with a cylindrical three layers device

    Science.gov (United States)

    Jannot, Y.; Degiovanni, A.

    2013-09-01

    This paper presents a new method dedicated to thermal properties (conductivity and diffusivity) measurement of dry bulk materials including powders. The cylindrical three layers experimental device (brass/bulk material/stainless steel) and the principle of the measurement method based on a crenel thermal excitation are presented. The one-dimensional modeling of the system is used for a sensitivity analysis and to calculate the standard deviation of the estimation error. Experimental measurements are carried out on three bulk materials: glass beads, cork granules, and expanded polystyrene beads. The estimated thermal properties are compared with the values obtained by other measurement methods. Results are in good agreement with theoretical predictions: both thermal conductivity and diffusivity can be estimated with a good accuracy for low density material like cork granules or expanded polystyrene beads since only thermal diffusivity can be estimated for heavier materials like glass beads. It is finally shown that this method like all transient methods is not suited to the thermal characterization of wet bulk materials.

  1. The microstructure of MX-80 clay with respect to its bulk physical properties under different environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, R. [Geodevelopment AB, Lund (Sweden)

    2001-03-01

    A model of microstructural evolution of MX-80 buffer is presented in the report.Quantification of the microstructure is made by use of digitalized micrographs taken by transmission electron microscopy using suitably impregnated specimens with appropriate thickness. The model is termed MMM, a successor of the earlier GMM. Practically useful microstructural parameters refer to the fraction of a thin section that represents dense and soft parts of the clay matrix. The derived microstructural parameters are directly coupled to the most important bulk physical properties, i.e. the hydraulic conductivity, gas penetrability, swelling pressure and cation/anion diffusion capacities. The study has shown that even at very high densities, softer and more pervious zones exist in the form of interconnected 'external' voids filled with more or less dense clay gels. At bulk densities exceeding 2000 kg/m{sup 3} after water saturation, the gel density is also high but for low bulk densities it may be so much reduced that the gels do not remain stable at high electrolyte content of the pore water. The fact that the density variations are small for high bulk densities means that the separation of matrix components ('fracturing') that is required for letting gas through is on the same order of magnitude as the bulk swelling pressure. For lower bulk densities, displacement or consolidation of the clay gels in 'external' voids is concluded to take place in conjunction with gas penetration. At high densities the limited degree of continuity and constrictions of the channels leading to anion-excluding charge conditions mean that the anion diffusion capacity is very low, while cation diffusion may be extensive because it takes place not only through channels but also through the inter lamellar space and along the surfaces of stacks of lamellae, i.e. by surface diffusion. Two Pre-Quaternary clays that have been investigated and characterized with respect to the

  2. Density matrix embedding theory for interacting electron-phonon systems

    Science.gov (United States)

    Sandhoefer, Barbara; Chan, Garnet Kin-Lic

    2016-08-01

    We describe the extension of the density matrix embedding theory framework to coupled interacting fermion-boson systems. This provides a frequency-independent, entanglement embedding formalism to treat bulk fermion-boson problems. We illustrate the concepts within the context of the one-dimensional Hubbard-Holstein model, where the phonon bath states are obtained from the Schmidt decomposition of a self-consistently adjusted coherent state. We benchmark our results against accurate density matrix renormalization group calculations.

  3. High--order jamming crossovers and density anomalies

    OpenAIRE

    Ciamarra, Massimo Pica; Sollich, Peter

    2012-01-01

    We demonstrate the existence of high--order jamming crossovers in systems of particles with repulsive contact interactions, which originate from the collapse of successive coordination shells. At zero temperature, these crossovers induce an anomalous behavior of the bulk modulus, which varies non--monotonically with the density, while at finite temperature they induce density anomalies consisting in an increased diffusivity upon isothermal compression and in a negative thermal expansion coeff...

  4. A CFT Perspective on Gravitational Dressing and Bulk Locality

    CERN Document Server

    Lewkowycz, Aitor; Verlinde, Herman

    2016-01-01

    We revisit the construction of local bulk operators in AdS/CFT with special focus on gravitational dressing and its consequences for bulk locality. Specializing to 2+1-dimensions, we investigate these issues via the proposed identification between bulk operators and cross-cap boundary states. We obtain explicit expressions for correlation functions of bulk fields with boundary stress tensor insertions, and find that they are free of non-local branch cuts but do have non-local poles. We recover the HKLL recipe for restoring bulk locality for interacting fields as the outcome of a natural CFT crossing condition. We show that, in a suitable gauge, the cross-cap states solve the bulk wave equation for general background geometries, and satisfy a conformal Ward identity analogous to a soft graviton theorem, Virasoro symmetry, the large N conformal bootstrap and the uniformization theorem all play a key role in our derivations.

  5. Determination of Bulk Dimensional Variation in Castings

    Energy Technology Data Exchange (ETDEWEB)

    Dr. James F. Cuttino Dr. Edward P. Morse

    2005-04-14

    The purpose of this work is to improve the efficiency of green sand foundries so that they may continue to compete as the most cost-effective method of fabrication while meeting tightening constraints on near-net shape manufacturing. In order to achieve this objective, the study is divided into two major components. The first component concentrated on identifying which processes control surface finish on the castings and which provide potential reductions in variations. The second component identified metrological methods that effectively discern between the geometry of bulk material versus surface finish in order to more accurately determine the quality of a part. The research resulted in the determination of an empirical relationship relating pouring parameters to dimensional variation, with an R2 value of greater than 0.79. A significant difference in variations obtained from vertical vs. horizontal molding machines was also noticed. When analyzed separately, however, the resulting empirical relationships for horizontal and vertical machines had reduced R2 values, probably due to the reduced data sets. Significant parameters when considering vertical and horizontal molding machines together included surface roughness, pattern type, iron type, pouring rate, copper content, amount of Western Bentonite, and permeability.

  6. Studies of bulk heterojunction solar cells

    Science.gov (United States)

    Cossel, Raquel; McIntyre, Max; Tzolov, Marian

    We are studying bulk heterojunction solar cells that were fabricated using a mixture of PCPDTBT and PCBM­C60. The impedance data of the cells in dark responded like a simple RC circuit. The value of the dielectric constant derived from these results is consistent with the values reported in the literature for these materials. We are showing that the parallel resistance in the equivalent circuit of linear lump elements can be interpreted using the DC current­voltage measurements. The impedance spectra under light illumination indicated the existence of additional polarization. This extra feature can be described by a model that includes a series RC circuit in parallel with the equivalent circuit for a device in dark. The physical interpretation of the additional polarization is based on photo­generated charges getting trapped in wells, which have a characteristic relaxation time corresponding to the observed break frequency in the impedance spectra. We have studied the influence of the anode and cathode interface on this phenomena, either by using different interface materials, or by depositing the metal electrode while the substate is heated.

  7. Material Profile Influences in Bulk-Heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Roehling, John D.; Rochester, Christopher W.; Ro, Hyun W.; Wang, Peng; Majewski, Jaroslaw; Batenburg, Kees J.; Arslan, Ilke; Delongchamp, Dean M.; Moule, Adam J.

    2014-10-01

    he morphology in mixed bulk-heterojunction films are compared using three different quantitative measurement techniques. We compare the vertical composition changes using high-angle annular dark-field scanning transmission electron microscopy with electron tomography and neutron and x-ray reflectometry. The three measurement techniques yield qualita-tively comparable vertical concentration measurements. The presence of a metal cathode during thermal annealing is observed to alter the fullerene concentration throughout the thickness of the film for all measurements. However, the abso-lute vertical concentration of fullerene is quantitatively different for the three measurements. The origin of the quantitative measurement differences is discussed. The authors thank Luna Innovations, Inc. for donating the endohedral fullerenes used in this study and Plextronics for the P3HT. They are gratefully thank the National Science Foundation Energy for Sustainability Program, Award No. 0933435. This work benefited from the use of the Lujan Neutron Scattering Center at Los Alamos Neutron Science Center funded by the DOE Office of Basic Energy Sciences and Los Alamos National Laboratory under DOE Contract DE-AC52-06NA25396. This research was also supported in part by Laboratory Directed Research & Development program at PNNL. The Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy under contract DE-AC05-76RL01830.

  8. Failure Prediction in Bulk Metal Forming Process

    Directory of Open Access Journals (Sweden)

    Ameen Topa

    2014-01-01

    Full Text Available An important concern in metal forming is whether the desired deformation can be accomplished without defects in the final product. Various ductile fracture criteria have been developed and experimentally verified for a limited number of cases of metal forming processes. These criteria are highly dependent on the geometry of the workpiece and cannot be utilized for complicated shapes without experimental verification. However, experimental work is a resource hungry process. This paper proposes the ability of finite element analysis (FEA software such as LS-DYNA to pinpoint the crack-like flaws in bulk metal forming products. Two different approaches named as arbitrary Lagrangian-Eulerian (ALE and smooth particle hydrodynamics (SPH formulations were adopted. The results of the simulations agree well with the experimental work and a comparison between the two formulations has been carried out. Both approximation methods successfully predicted the flow of workpiece material (plastic deformation. However ALE method was able to pinpoint the location of the flaws.

  9. Casimir effect in dielectrics: Bulk energy contribution

    International Nuclear Information System (INIS)

    In a recent series of papers, Schwinger discussed a process that he called the dynamical Casimir effect. The key essence of this effect is the change in zero-point energy associated with any change in a dielectric medium. (In particular, if the change in the dielectric medium is taken to be the growth or collapse of a bubble, this effect may have relevance to sonoluminescence.) The kernel of Schwinger close-quote s result is that the change in Casimir energy is proportional to the change in the volume of the dielectric, plus finite-volume corrections. Other papers have called into question this result, claiming that the volume term should actually be discarded, and that the dominant term remaining is proportional to the surface area of the dielectric. In this paper, which is an expansion of an earlier Letter on the same topic, we present a careful and critical review of the relevant analyses. We find that the Casimir energy, defined as the change in zero-point energy due to a change in the medium, has at leading order a bulk volume dependence. This is in full agreement with Schwinger close-quote s result, once the correct physical question is asked. We have nothing new to say about sonoluminescence itself. copyright 1997 The American Physical Society

  10. Photoelectron spectroscopy bulk and surface electronic structures

    CERN Document Server

    Suga, Shigemasa

    2014-01-01

    Photoelectron spectroscopy is now becoming more and more required to investigate electronic structures of various solid materials in the bulk, on surfaces as well as at buried interfaces. The energy resolution was much improved in the last decade down to 1 meV in the low photon energy region. Now this technique is available from a few eV up to 10 keV by use of lasers, electron cyclotron resonance lamps in addition to synchrotron radiation and X-ray tubes. High resolution angle resolved photoelectron spectroscopy (ARPES) is now widely applied to band mapping of materials. It attracts a wide attention from both fundamental science and material engineering. Studies of the dynamics of excited states are feasible by time of flight spectroscopy with fully utilizing the pulse structures of synchrotron radiation as well as lasers including the free electron lasers (FEL). Spin resolved studies also made dramatic progress by using higher efficiency spin detectors and two dimensional spin detectors. Polarization depend...

  11. Bulk viscous cosmology: statefinder and entropy

    CERN Document Server

    He, X

    2006-01-01

    The statefinder diagnostic pair is adopted to differentiate viscous cosmology models and it is found that the trajectories of these viscous cosmology models on the statefinder pair $s-r$ plane are quite different from those of the corresponding non-viscous cases. Particularly for the quiessence model, the singular properties of state parameter $w=-1$ are obviously demonstrated on the statefinder diagnostic pair planes. We then discuss the entropy of the viscous / dissipative cosmology system which may be more practical to describe the present cosmic observations as the perfect fluid is just a global approximation to the complicated cosmic media in current universe evolution. When the bulk viscosity takes the form of $\\zeta=\\zeta_{1}\\dot{a}/a$($\\zeta_{1}$ is constant), the relationship between the entropy $S$ and the redshift $z$ is explicitly given out. We find that the entropy of the viscous cosmology is always increasing and consistent with the thermodynamics arrow of time for the universe evolution. With t...

  12. Thermodynamic properties of bulk and confined water

    Energy Technology Data Exchange (ETDEWEB)

    Mallamace, Francesco, E-mail: francesco.mallamace@unime.it [Dipartimento di Fisica e Scienza della Terra Università di Messina and CNISM, I-98168 Messina (Italy); Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215 (United States); Corsaro, Carmelo [Dipartimento di Fisica e Scienza della Terra Università di Messina and CNISM, I-98168 Messina (Italy); Mallamace, Domenico [Dipartimento di Scienze dell' Ambiente, della Sicurezza, del Territorio, degli Alimenti e della Salute, Università di Messina, I-98166 Messina (Italy); Vasi, Sebastiano; Vasi, Cirino [IPCF-CNR, I-98166 Messina (Italy); Stanley, H. Eugene [Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215 (United States)

    2014-11-14

    The thermodynamic response functions of water display anomalous behaviors. We study these anomalous behaviors in bulk and confined water. We use nuclear magnetic resonance (NMR) to examine the configurational specific heat and the transport parameters in both the thermal stable and the metastable supercooled phases. The data we obtain suggest that there is a behavior common to both phases: that the dynamics of water exhibit two singular temperatures belonging to the supercooled and the stable phase, respectively. One is the dynamic fragile-to-strong crossover temperature (T{sub L} ≃ 225 K). The second, T{sup *} ∼ 315 ± 5 K, is a special locus of the isothermal compressibility K{sub T}(T, P) and the thermal expansion coefficient α{sub P}(T, P) in the P–T plane. In the case of water confined inside a protein, we observe that these two temperatures mark, respectively, the onset of protein flexibility from its low temperature glass state (T{sub L}) and the onset of the unfolding process (T{sup *})

  13. On methods of estimating cosmological bulk flows

    CERN Document Server

    Nusser, Adi

    2015-01-01

    We explore similarities and differences between several estimators of the cosmological bulk flow, $\\bf B$, from the observed radial peculiar velocities of galaxies. A distinction is made between two theoretical definitions of $\\bf B$ as a dipole moment of the velocity field weighted by a radial window function. One definition involves the three dimensional (3D) peculiar velocity, while the other is based on its radial component alone. Different methods attempt at inferring $\\bf B$ for either of these definitions which coincide only for a constant velocity field. We focus on the Wiener Filtering (WF, Hoffman et al. 2015) and the Constrained Minimum Variance (CMV,Feldman et al. 2010) methodologies. Both methodologies require a prior expressed in terms of the radial velocity correlation function. Hoffman et al. compute $\\bf B$ in Top-Hat windows from a WF realization of the 3D peculiar velocity field. Feldman et al. infer $\\bf B$ directly from the observed velocities for the second definition of $\\bf B$. The WF ...

  14. Recent developments of film bulk acoustic resonators

    Science.gov (United States)

    Gao, Junning; Liu, Guorong; Li, Jie; Li, Guoqiang

    2016-06-01

    Film bulk acoustic wave resonator (FBAR) experienced skyrocketing development in the past 15 years, owing to the explosive development of mobile communication. It stands out in acoustic filters mainly because of high quality factor, which enables low insertion loss and sharp roll off. Except for the massive application in wireless communication, FBARs are also promising sensors because of the high sensitivity and readily integration ability to miniaturize circuits. On the ground of summarizing FBAR’s application in wireless communication as filters and in sensors including electronic nose, bio field, and pressure sensing, this paper review the main challenges of each application faced. The number of filters installed in the mobile phone has being grown explosively, which leads to overcrowded bands and put harsh requirements on component size and power consumption control for each unit. Data flow and rate are becoming increasingly demanding as well. This paper discusses three promising technical strategies addressing these issues. Among which coupled resonator filter is given intense attention because it is able to vigorously reduce the filter size by stacking two or more resonators together, and it is a great technique to increase data flow and rate. Temperature compensation methods are discussed considering their vital influence on frequency stability. Finally, materials improvement and novel materials exploration for band width modulation, tunable band acquisition, and quality factor improvement are discussed. The authors appeal attention of the academic society to bring AlN epitaxial thin film into the FBAR fabrication and have proposed a configuration to implement this idea.

  15. Advances in Processing of Bulk Ferroelectric Materials

    Science.gov (United States)

    Galassi, Carmen

    The development of ferroelectric bulk materials is still under extensive investigation, as new and challenging issues are growing in relation to their widespread applications. Progress in understanding the fundamental aspects requires adequate technological tools. This would enable controlling and tuning the material properties as well as fully exploiting them into the scale production. Apart from the growing number of new compositions, interest in the first ferroelectrics like BaTiO3 or PZT materials is far from dropping. The need to find new lead-free materials, with as high performance as PZT ceramics, is pushing towards a full exploitation of bariumbased compositions. However, lead-based materials remain the best performing at reasonably low production costs. Therefore, the main trends are towards nano-size effects and miniaturisation, multifunctional materials, integration, and enhancement of the processing ability in powder synthesis. Also, in control of dispersion and packing, to let densification occur in milder conditions. In this chapter, after a general review of the composition and main properties of the principal ferroelectric materials, methods of synthesis are analysed with emphasis on recent results from chemical routes and cold consolidation methods based on the colloidal processing.

  16. On methods of estimating cosmological bulk flows

    Science.gov (United States)

    Nusser, Adi

    2016-01-01

    We explore similarities and differences between several estimators of the cosmological bulk flow, B, from the observed radial peculiar velocities of galaxies. A distinction is made between two theoretical definitions of B as a dipole moment of the velocity field weighted by a radial window function. One definition involves the three-dimensional (3D) peculiar velocity, while the other is based on its radial component alone. Different methods attempt at inferring B for either of these definitions which coincide only for the case of a velocity field which is constant in space. We focus on the Wiener Filtering (WF) and the Constrained Minimum Variance (CMV) methodologies. Both methodologies require a prior expressed in terms of the radial velocity correlation function. Hoffman et al. compute B in Top-Hat windows from a WF realization of the 3D peculiar velocity field. Feldman et al. infer B directly from the observed velocities for the second definition of B. The WF methodology could easily be adapted to the second definition, in which case it will be equivalent to the CMV with the exception of the imposed constraint. For a prior with vanishing correlations or very noisy data, CMV reproduces the standard Maximum Likelihood estimation for B of the entire sample independent of the radial weighting function. Therefore, this estimator is likely more susceptible to observational biases that could be present in measurements of distant galaxies. Finally, two additional estimators are proposed.

  17. Power balance in ELMO Bumpy Torus: bulk electrons and ions in a 37 kW discharge

    Energy Technology Data Exchange (ETDEWEB)

    McNeill, D.H.

    1985-10-01

    The power balance of the bulk electrons and ions in discharges with 37 kW of applied microwave power in the ELMO Bumpy Torus (EBT) is examined in a zero-dimensional model using data on the intensity and linewidth of the molecular and atomic hydrogen emission. At least 60% of the applied power is ultimately dissipated by processes involving the neutral particles, including dissociation of molecules, ionization of and radiation from atoms, and heating of cold electrons produced during atomic ionization. The molecular influx rate and the density of atoms are used independently to determine the bulk electron particle confinement time, and an upper bound estimate is made of the diffusional power loss from the bulk plasma electrons. Parameters derived from the basic spectroscopic data presented in this paper include the neutral atom density 2 - 5x10/sup 10/ cm/sup -3/, incident molecular flux 3 - 5x10/sup 15/ cm/sup -2/s/sup -1/, bulk ion temperature approx. =3 eV, and particle confinement time <1.1 ms. The bulk electron energy confinement time is 0.7 ms or less in the standard operating regime. Published data on the nonthermal electron and ion populations in the plasma are used to evaluate approximately the overall energy flow in the discharge. 54 refs.

  18. Power balance in ELMO Bumpy Torus: bulk electrons and ions in a 37 kW discharge

    International Nuclear Information System (INIS)

    The power balance of the bulk electrons and ions in discharges with 37 kW of applied microwave power in the ELMO Bumpy Torus (EBT) is examined in a zero-dimensional model using data on the intensity and linewidth of the molecular and atomic hydrogen emission. At least 60% of the applied power is ultimately dissipated by processes involving the neutral particles, including dissociation of molecules, ionization of and radiation from atoms, and heating of cold electrons produced during atomic ionization. The molecular influx rate and the density of atoms are used independently to determine the bulk electron particle confinement time, and an upper bound estimate is made of the diffusional power loss from the bulk plasma electrons. Parameters derived from the basic spectroscopic data presented in this paper include the neutral atom density 2 - 5x1010 cm-3, incident molecular flux 3 - 5x1015 cm-2s-1, bulk ion temperature approx. =3 eV, and particle confinement time <1.1 ms. The bulk electron energy confinement time is 0.7 ms or less in the standard operating regime. Published data on the nonthermal electron and ion populations in the plasma are used to evaluate approximately the overall energy flow in the discharge. 54 refs

  19. Nanocomposite RE-Ba-Cu-O bulk superconductors

    OpenAIRE

    Iida, Kazumasa

    2016-01-01

    Nanocomposite oxide high-temperature bulk superconductors can be used as quasi-magnets. Thanks to the recent progress of material processing, quasi-magnet with 26 mm diameter can generate a large field of 17.6 T at 26 K. These results are highly attractive for applications, involving levitation of permanent magnets on the bulk superconductors. Indeed, several other applications such as motors and magnetic resonance microscope using bulk superconductors have been proposed and demonstrated. In ...

  20. Can local bulk effects explain the galactic dark matter?

    Energy Technology Data Exchange (ETDEWEB)

    Heydari-Fard, Malihe; Sepangi, Hamid R, E-mail: m.heydarifard@mail.sbu.ac.ir, E-mail: hr-sepangi@sbu.ac.ir [Department of Physics, Shahid Beheshti University, Evin, Tehran 19839 (Iran, Islamic Republic of)

    2008-08-15

    We obtain the virial theorem within the context of a brane-world model without mirror symmetry or any form of junction condition. Taking a constant curvature bulk (neglecting non-local bulk effects), the local bulk effects generate a geometrical mass, contributing to the gravitational energy which may be used to explain the virial mass discrepancy in clusters of galaxies. We fix the parameters of this model in agreement with observational data.

  1. Can local bulk effects explain the galactic dark matter?

    OpenAIRE

    Heydari-Fard, Malihe; Sepangi, Hamid R.

    2008-01-01

    We obtain the virial theorem within the context of a brane-world model without mirror symmetry or any form of junction condition. Taking a constant curvature bulk (neglecting non-local bulk effects), the local bulk effects generate a geometrical mass, contributing to the gravitational energy which may be used to explain the virial mass discrepancy in clusters of galaxies. We fix the parameter of this model in agreement with observational data.

  2. Extracting the bulk viscosity of the quark–gluon plasma

    International Nuclear Information System (INIS)

    We investigate the implications of a nonzero bulk viscosity coefficient on the azimuthal momentum anisotropy of ultracentral relativistic heavy ion collisions at the Large Hadron Collider. We find that, with IP-Glasma initial conditions, a finite bulk viscosity coefficient leads to a better description of the flow harmonics in ultracentral collisions. We then extract optimal values of bulk and shear viscosity coefficients that provide the best agreement with flow harmonic coefficients data in this centrality class

  3. A density gradient theory based method for surface tension calculations

    DEFF Research Database (Denmark)

    Liang, Xiaodong; Michelsen, Michael Locht; Kontogeorgis, Georgios

    2016-01-01

    The density gradient theory has been becoming a widely used framework for calculating surface tension, within which the same equation of state is used for the interface and bulk phases, because it is a theoretically sound, consistent and computationally affordable approach. Based on the observati...

  4. Bulk flow scaling for turbulent channel and pipe flows

    CERN Document Server

    Chen, Xi; She, Zhen-Su

    2016-01-01

    We report a theory deriving bulk flow scaling for canonical wall-bounded flows. The theory accounts for the symmetries of boundary geometry (flat plate channel versus circular pipe) by a variational calculation for a large-scale energy length, which characterizes its bulk flow scaling by a simple exponent, i.e. $m=4$ for channel and 5 for pipe. The predicted mean velocity shows excellent agreement with several dozen sets of quality empirical data for a wide range of the Reynolds number (Re), with a universal bulk flow constant $\\kappa\\approx0.45$. Predictions for dissipation and turbulent transport in the bulk flow are also given, awaiting data verification.

  5. Locality, bulk equations of motion and the conformal bootstrap

    CERN Document Server

    Kabat, Daniel

    2016-01-01

    We develop an approach to construct local bulk operators in a CFT to order 1/N^2. Since 4-point functions are not fixed by conformal invariance we use the OPE to categorize possible forms for a bulk operator. Using previous results on 3-point functions we construct a local bulk operator in each OPE channel. We then impose the condition that the bulk operators constructed in different channels agree, and hence give rise to a well-defined bulk operator. We refer to this condition as the "bulk bootstrap." We argue and explicitly show in some examples that the bulk bootstrap leads to some of the same results as the regular conformal bootstrap. In fact the bulk bootstrap provides an easier way to determine some CFT data, since it does not require knowing the form of the conformal blocks. This analysis clarifies previous results on the relation between bulk locality and the bootstrap for theories with a 1/N expansion, and it identifies a simple and direct way in which OPE coefficients and anomalous dimensions deter...

  6. Exchange–correlation errors at harmonic and anharmonic orders: the case of bulk Cu

    Indian Academy of Sciences (India)

    Shobhana Narasimhan; Stefano De Gironcoli

    2003-01-01

    As an aid towards improving the treatment of exchange and correlation effects in electronic structure calculations, it is desirable to have a clear picture of the errors introduced by currently popular approximate exchange–correlation functionals. We have performed ab initio density functional theory and density functional perturbation theory calculations to investigate the thermal properties of bulk Cu, using both the local density approximation (LDA) and the generalized gradient approximation (GGA). Thermal effects are treated within the quasiharmonic approximation. We find that the LDA and GGA errors for anharmonic quantities are an order of magnitude smaller than for harmonic quantities; we argue that this might be a general feature. We also obtain much closer agreement with experiment than earlier, more approximate calculations.

  7. Crystallization of a Ti-based Bulk Metallic Glass Induced by Electropulsing Treatment

    Institute of Scientific and Technical Information of China (English)

    Yong-jiang HUANG; Xiang CHENG; Hong-bo FAN; Shi-song GUAN; Zhi-liang NING; Jian-fei SUN

    2016-01-01

    The effect of electropulsing treatment (EPT)on the microstructure of a Ti-based bulk metallic glass (BMG)has been studied.The maximum current density applied during EPT can exert a crucial role on tuning the microstructure of the BMG.When the maximum current density is no more than 2 720 A/mm2 ,the samples retains amorphous nature,whereas,beyond that,crystalline phases precipitate from the glassy matrix.During EPT,the maximum temperature within the samples EPTed at the maximum current densities larger than 2 720 A/mm2 is higher than the crystallization temperature of the BMG,leading to the crystallization event.

  8. Plasmon-enhanced polymer bulk heterojunction solar cells with solution-processable Ag nanoparticles

    Institute of Scientific and Technical Information of China (English)

    YAN Qi-qi; QIN Wen-jing; WANG Chao; SONG Peng-fei; DING Guo-jing; YANG Li-ying; YIN Shou-gen

    2011-01-01

    We report the plasmon-enhanced polymer bulk-heterojunction solar cells with Ag nanoparticles (AgNPs) obtained via chemical method.Here,the AgNPs films with different particle densities are introduced between the poly (3,4-ethylene dioxythiophene) poly (styrenesulfonate) (PEDOT:PSS) buffer layer and the poly (3-hexythiophene):[6,6]-phenyl-C61 butyric acid methyl ester (P3HT:PCBM) layer.By improving the optical absorption of the active layer owing to the localized surface plasmons,the power conversion efficiency of the solar cells is increased compared with the control device.It is shown that the efficiency of the device increases with the density of AgNPs.For the device employing higher density,the resulted power conversion efficiency is found to increase from 2.89% to 3.38%,enhanced by 16.96%.

  9. Bulk, thermal, and mechanical properties of the Topopah Spring Member of the Paintbrush Tuff, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Experimental data on matrix porosity, grain density, thermal expansion, compressive strength, Young's modulus, Poisson's ratio, and axial strain at failure for samples from the Topopah Spring Member of the Paintbrush Tuff are compiled. Heat capacity and emissivity also are discussed. Data have been analyzed for spatial variability; slight variability is observed for matrix porosity, grain density, and thermal expansion coefficient. Estimates of in situ values for some properties, such as bulk density and heat capacity, are presented. Vertical in situ stress as a function of horizontal and vertical location has been calculated. 96 refs., 37 figs., 27 tabs

  10. An experimental comparison of laboratory techniques in determining bulk properties of tuffaceous rocks; Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, P.J.; Martin, R.J. III [New England Research, Inc., White River Junction, VT (United States); Price, R.H. [Sandia National Labs., Albuquerque, NM (United States). YMP Performance Assessment Applications Dept.

    1994-04-01

    Samples of tuffaceous rock were studied as part of the site characterization for a potential nuclear waste repository at Yucca Mountain in southern Nevada. These efforts were scoping in nature, and their results, along with those of other investigations, are being used to develop suitable procedures for determining bulk properties of tuffaceous rock in support of thermal and mechanical properties evaluations. Comparisons were made between various sample preparation, handling, and measurement techniques for both zeolitized and nonzeolitized tuff in order to assess their effects on bulk property determinations. Laboratory tests included extensive drying regimes to evaluate dehydration behavior, the acquisition of data derived from both gas and water pycnometers to compare their suitability in determining grain densities, a comparison of particle size effects, and a set of experiments to evaluate whole core saturation methods. The results affirm the added complexity of these types of measurements where there is a zeolite component in the sample mineralogy. Absolute values for the bulk properties of zeolitized tuff are immeasurable due to the complex nature of their dehydration behavior. However, the results of the techniques that were investigated provide a basis for the development of preferred, consistent methods for determining the grain density, dry and saturated bulk densities, and porosity of tuffaceous rock, including zeolitic tuff in support of thermal and mechanical properties evaluations.

  11. A comparison study on the electronic structures, lattice dynamics and thermoelectric properties of bulk silicon and silicon nanotubes

    Science.gov (United States)

    Lu, Peng-Xian; Qu, Ling-Bo; Cheng, Qiao-Huan

    2013-11-01

    In order to investigate the mechanism of the electron and phonon transport in a silicon nanotube (SiNT), the electronic structures, the lattice dynamics, and the thermoelectric properties of bulk silicon (bulk Si) and a SiNT have been calculated in this work using density functional theory and Boltzmann transport theory. Our results suggest that the thermal conductivity of a SiNT is reduced by a factor of 1, while its electrical conductivity is improved significantly, although the Seebeck coefficient is increased slightly as compared to those of the bulk Si. As a consequence, the figure of merit (ZT) of a SiNT at 1200 K is enhanced by 12 times from 0.08 for bulk Si to 1.10. The large enhancement in electrical conductivity originates from the largely increased density of states at the Fermi energy level and the obviously narrowed band gap. The significant reduction in thermal conductivity is ascribed to the remarkably suppressed phonon thermal conductivity caused by a weakened covalent bonding, a decreased phonon density of states, a reduced phonon vibration frequency, as well as a shortened mean free path of phonons. The other factors influencing the thermoelectric properties have also been studied from the perspective of electronic structures and lattice dynamics.

  12. A novel carbon nanotubefet based bulk built-in current sensor for single event upset detection

    Indian Academy of Sciences (India)

    T R RAJALAKSHMI; R SUDHAKAR

    2016-05-01

    The continuous scaling down of circuits has resulted in the development of carbon nanotubes (CNT) which provides a better alternative of silicon. High device packing densities is one of the advantageous factors of CNTFET compared to CMOS technology. This paper describes the new bulk current based built-in current sensor (BBICS) for the detection of single event upset (SEU) in CNTFET SRAM with less number of transistors compared to previous designs. The advantage of it is that its ability to detect low ranges of microcurrent. The complete circuit, both SRAM and Sensor are built with CNTFET. This also possesses the advantage of being used in the detection of negative current pulses with the addition of an inverter circuit. This circuitoperates best for two different technology nodes. This built-in current sensor is connected to the bulk terminal of the CNTFET SRAM. PVT analysis and power dissipation analysis were done for the proposed circuit.

  13. Xerophilic mycopopulations of teas in bulk

    Directory of Open Access Journals (Sweden)

    Škrinjar Marija M.

    2011-01-01

    Full Text Available d.o.o., Novi Sad AU Krunić Vesna J. AF EKOLd.o.o., Novi Sad KW teas % mould contamination % thermal treatment KR nema Other the water, tea is the most popular beverage in the world today. They are used for ages, in the beginning as refreshing drinks, and later more for their healing properties. Teas have been demonstrated to show antioxidative, anti-carcinogenic, and anti-microbial properties. Considering that the teas, during the production, are not treated with any temperature, there is high risk for contamination with different type of microorganisms, especially with moulds. Moulds are ubiquitously distributed in nature and their spores can be found in the atmosphere even at high altitudes and under favorable conditions of temperature and humidity, moulds grow on many commodities including cereals, oil seeds, nuts, herbs and spices. Most of them are potential producers of mycotoxins which present a real hazard to human health. The aim of this work was to investigate total mould count and to identify moulds isolated from teas in bulk, than from teas treated with hot, sterile, distilled water and from the tea filtrates. Tested teas were peppermint, sage, yarrow, black tea, bearberry, lemon balm, mixture of teas from Zlatibor. In teas in balk was observed high contamination with different kinds of moulds (1.84-4.55 cfu/g, such as Aspergillus awamori, A. lovaniensis, A niger, A. phoenicus, A. repens, A. restrictus, A. sydowii, A. versicolor, Eurotium amstelodami, E. chevalieri, E. herbariorum, Penicillium chrysogenum, and Scopulariopsis brevicaulis. The most frequent were species from Aspergillus and Eurotium genera. Thermal treatment with hot, sterile, distilled water reduced the number of fungal colonies. Aspergillus awamori was the most resistant and appeared in six samples of filtrates of tea, Aspergillus niger in one sample and Penicillium chrysogenum in one sample.

  14. Cavitation instability in bulk metallic glasses

    Science.gov (United States)

    Dai, L. H.; Huang, X.; Ling, Z.

    2015-09-01

    Recent experiments have shown that fracture surfaces of bulk metallic glasses (BMGs) usually exhibit an intriguing nanoscale corrugation like fractographic feature mediated by nanoscale void formation. We attribute the onset of this nanoscale corrugation to TTZs (tension transformation zones) mediated cavitation. In our recent study, the spall experiments of Zr-based BMG using a single-stage light gas gun were performed. To uncover the mechanisms of the spallation damage nucleation and evolution, the samples were designed to be subjected to dynamic tensile loadings of identical amplitude but with different durations by making use of the multi-stress pulse and the double-flyer techniques. It is clearly revealed that the macroscopic spall fracture in BMGs originates from the nucleation, growth and coalescence of micro-voids. Then, a microvoid nucleation model of BMGs based on free volume theory is proposed, which indicates that the nucleation of microvoids at the early stage of spallation in BMGs is resulted from diffusion and coalescence of free volume. Furthermore, a theoretical model of void growth in BMGs undergoing remote dynamic hydrostatic tension is developed. The critical condition of cavitation instability is obtained. It is found that dynamic void growth in BMGs can be well controlled by a dimensionless inertial number characterizing the competition between intrinsic and extrinsic time scales. To unveil the atomic-level mechanism of cavitation, a systematic molecular dynamics (MD) simulation of spallation behaviour of a binary metallic glass with different impact velocities was performed. It is found that micro-void nucleation is determined TTZs while the growth is controlled by shear transformation zones (STZs) at atomic scale.

  15. Cavitation instability in bulk metallic glasses

    Directory of Open Access Journals (Sweden)

    Dai L.H.

    2015-01-01

    Full Text Available Recent experiments have shown that fracture surfaces of bulk metallic glasses (BMGs usually exhibit an intriguing nanoscale corrugation like fractographic feature mediated by nanoscale void formation. We attribute the onset of this nanoscale corrugation to TTZs (tension transformation zones mediated cavitation. In our recent study, the spall experiments of Zr-based BMG using a single-stage light gas gun were performed. To uncover the mechanisms of the spallation damage nucleation and evolution, the samples were designed to be subjected to dynamic tensile loadings of identical amplitude but with different durations by making use of the multi-stress pulse and the double-flyer techniques. It is clearly revealed that the macroscopic spall fracture in BMGs originates from the nucleation, growth and coalescence of micro-voids. Then, a microvoid nucleation model of BMGs based on free volume theory is proposed, which indicates that the nucleation of microvoids at the early stage of spallation in BMGs is resulted from diffusion and coalescence of free volume. Furthermore, a theoretical model of void growth in BMGs undergoing remote dynamic hydrostatic tension is developed. The critical condition of cavitation instability is obtained. It is found that dynamic void growth in BMGs can be well controlled by a dimensionless inertial number characterizing the competition between intrinsic and extrinsic time scales. To unveil the atomic-level mechanism of cavitation, a systematic molecular dynamics (MD simulation of spallation behaviour of a binary metallic glass with different impact velocities was performed. It is found that micro-void nucleation is determined TTZs while the growth is controlled by shear transformation zones (STZs at atomic scale.

  16. Density profile of pyrolitic lower mantle

    Science.gov (United States)

    Sinmyo, R.; Hirose, K.; Ohishi, Y.

    2010-12-01

    Density profile of pyrolite at lower mantle high-pressure (P) and -temperature (T) conditions was investigated by using laser-heated diamond-anvil cell up to 117 GPa and 2800 K. The density was determined from chemical composition and unit-cell volume of each constituent mineral (MgSiO3-rich perovskite, ferropericlase and CaSiO3-rich perovskite). The chemical compositions of coexisting phases were analyzed by transmission electron microscope, and their volumes were obtained by in-situ X-ray diffraction measurements. To avoid extensive chemical segregation during laser-heating, sample was coated by gold that worked as a laser absorber (Sinmyo and Hirose 2010 PEPI). Results of chemical analyses show that Mg-Fe (total Fe) partitioning coefficient between MgSiO3-rich perovskite and ferropericlase [K* = (Fe*/Mg)Pv/(Fe*/Mg)Fp] is about 0.6, slightly higher than the value previously reported in the pyrolitic bulk composition (Murakami et al. 2005 GRL). The lower K* value in the previous study may be attributed to the chemical heterogeneity in the sample induced by strong temperature gradient during laser heating. The calculated density profile of pyrolite is indeed in good agreement with the PREM model within experimental errors, in contrast with the mismatch reported by the previous study (Ricolleau et al. 2009 GRL). Our results support the lower mantle has pyrolitic bulk composition, and thus it is not necessary to suppose the chemically stratification in the lower mantle.

  17. Direct Density Derivative Estimation.

    Science.gov (United States)

    Sasaki, Hiroaki; Noh, Yung-Kyun; Niu, Gang; Sugiyama, Masashi

    2016-06-01

    Estimating the derivatives of probability density functions is an essential step in statistical data analysis. A naive approach to estimate the derivatives is to first perform density estimation and then compute its derivatives. However, this approach can be unreliable because a good density estimator does not necessarily mean a good density derivative estimator. To cope with this problem, in this letter, we propose a novel method that directly estimates density derivatives without going through density estimation. The proposed method provides computationally efficient estimation for the derivatives of any order on multidimensional data with a hyperparameter tuning method and achieves the optimal parametric convergence rate. We further discuss an extension of the proposed method by applying regularized multitask learning and a general framework for density derivative estimation based on Bregman divergences. Applications of the proposed method to nonparametric Kullback-Leibler divergence approximation and bandwidth matrix selection in kernel density estimation are also explored. PMID:27140943

  18. Future Road Density

    Data.gov (United States)

    U.S. Environmental Protection Agency — Road density is generally highly correlated with amount of developed land cover. High road densities usually indicate high levels of ecological disturbance. More...

  19. Centre seeded infiltration and growth process for fabrication of large grain bulk YBCO/Ag superconducting composites

    Science.gov (United States)

    Parthasarathy, R.; Seshubai, V.

    2012-06-01

    We report the fabrication of a large grain bulk YBCO/Ag superconductor using a novel technique which we call Centre Seeded Infiltration and Growth Process (CSIGP). Using this technique, it has been made possible to get bulk YBCO/Ag composite sample with uniform grain growth textured along the c-axis. The resulting large grain sample has been found to have high critical current densities up to large magnetic fields. We correlate the improved superconducting and magnetic properties to the modified grain growth conditions employed in this fabrication technique.

  20. Information Geometric Density Estimation

    OpenAIRE

    Sun, Ke; Marchand-Maillet, Stéphane

    2014-01-01

    We investigate kernel density estimation where the kernel function varies from point to point. Density estimation in the input space means to find a set of coordinates on a statistical manifold. This novel perspective helps to combine efforts from information geometry and machine learning to spawn a family of density estimators. We present example models with simulations. We discuss the principle and theory of such density estimation.

  1. Evaluating Density Forecasts

    OpenAIRE

    Francis X. Diebold; Todd A. Gunther; Anthony S. Tay

    1997-01-01

    The authors propose methods for evaluating and improving density forecasts. They focus primarily on methods that are applicable regardless of the particular user's loss function, though they take explicit account of the relationships between density forecasts, action choices, and the corresponding expected loss throughout. They illustrate the methods with a detailed series of examples, and they discuss extensions to improving and combining suboptimal density forecasts, multistep-ahead density...

  2. Temperature dependence of Hall electron density of GaN-based heterostructures

    Institute of Scientific and Technical Information of China (English)

    Zhang Jin-Feng; Zhang Jin-Cheng; Hao Yue

    2004-01-01

    The theoretic calculation and analysis of the temperature dependence of Hall electron density of a sample AlGaN/GaN heterostructure has been carried out in the temperature range from 77 to 300K. The densities of the twodimensional electron gas and the bulk electrons are solved by self-consistent calculation of one-dimensional Schrodinger and Poisson equations at different temperatures, which allow for the variation of energy gap and structure strain, and are used for evaluation of the temperature dependence of Hall electron density. The calculated Hall electron density agrees with the measured one quite well with the appropriate bulk mobility data. Analysis revealed that for the temper ature range considered, even in the heterostructures with a small bulk conductance the factors that determine the Hall mobility and electron density could be of different sources, and not just the two-dimensional electron gas as generally supposed.

  3. Monte Carlo Simulations of Density Profiles for Hard-Sphere Chain Fluids Confined Between Surfaces

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Covering a wide range of bulk densities, density profiles for hard-sphere chain fluids (HSCFs) with chain length of 3,4,8,20,32 and 64 confined between two surfaces were obtained by Monte Carlo simulations using extended continuum configurational-bias (ECCB) method. It is shown that the enrichment of beads near surfaces is happened at high densities due to the bulk packing effect, on the contrary, the depletion is revealed at low densities owing to the configurational entropic contribution. Comparisons with those calculated by density functional theory presented by Cai et al. indicate that the agreement between simulations and predictions is good. Compressibility factors of bulk HSCFs calculated using volume fractions at surfaces were also used to test the reliability of various equations of state of HSCFs by different authors.

  4. Flux pinning effect in a melt textured YBCO bulk evaluated by using tension measurements

    Science.gov (United States)

    Lee, Joon Ho; Ahmad, Dawood; Kim, Byoung Joo; Cha, Myoungsik; Yang, Ho Soon; Kim, Young Cheol; Ko, Rock Kil; Jeong, Dae Young

    2013-01-01

    Research on the flux pinning effect in type-II superconductors has usually been focused on microor nanosize pinning centers, and mm-sized pinning centers have been relatively less studied. In order to investigate the flux pinning effect caused by mm-sized pinning centers, we introduce a tension measurement method in this research. A cm-sized melt-textured YBCO bulk, in which holes with a 2 mm diameter are made, is prepared. The YBCO bulk is field-cooled by using a strong magnet in liquid nitrogen, and the bulk and the magnet are separated from each other. Then, an attractive force ( f a ) between them is generated, and f a is detected by using a tension measuring device. As the distance ( d) between them is increased, f a increases at short distance and decreases at long distance, showing a maximum value, f am , at a specific distance. The measurement of f a is stopped when d reaches a value defined as the breaking distance ( d bk ), as if a `string' between the magnet and the YBCO bulk is broken. As the number of holes ( n) made in the YBCO bulk increases from 1 to 6, f am and d bk increase, in spite of the superconducting volume loss. f am and d bk for n ≥ 7 converge to nearly constant values, which are smaller than the values for n = 6. This means that the critical current density can be calculated by using f am or d bk for a sufficient number of holes.

  5. Bulk coolant cavitation in LMFBR containment loading following a whole-core explosion

    International Nuclear Information System (INIS)

    An LMFBR core undergoing an explosion transmits energy to the containment in a series of pressure waves and the containment loading is determined by their cumulative effect. These pressure waves are modified by their interaction with the coolant through which they propagate. In liquids in their normal state the main effect of the interaction is to steepen the fronts of waves leading to shock formation but in liquids which have undergone bulk cavitation the interaction is much stronger and is expected to be dissipative and dispersive. Since reflections of initial pressure waves from the core at free surfaces lead to the establishment of a state of tension and consequently of bulk cavitation over large volumes of the coolant, it is necessary to model both the induction of bulk cavitation by tension waves and the interaction of pressure waves with cavitated liquid in realistic containment loading calculations. This paper sets out the progress which has been achieved in such modelling and first indications for the effect of bulk coolant cavitation in LMFBR containment loading. A model describing the interaction between cavitation bubbles and a host liquid subject to time-varying pressure fields, including the physical process of momentum conservation, phase change, heat conduction and mass diffusion is presented and used to a) determine which of the various physical processes involved dominate the results. It is shown that if we are only interested in bulk effects momentum transfer is the chief factor for the pressures and timescales of interest. b) determine the effect of the state of purity of the liquid. The main characterising parameters are the initial radii of nucleation sites and their number density, the latter being very influential. c) identify the important differences between model water and reactor sodium as far as cavitation is concerned. These are chiefly the lower surface tension and higher concentration of initially larger nucleation sites in the

  6. Crowding and Density

    Science.gov (United States)

    Design and Environment, 1972

    1972-01-01

    Three-part report pinpointing problems and uncovering solutions for the dual concepts of density (ratio of people to space) and crowding (psychological response to density). Section one, A Primer on Crowding,'' reviews new psychological and social findings; section two, Density in the Suburbs,'' shows conflict between status quo and increased…

  7. T-Duality Simplifies Bulk-Boundary Correspondence

    Science.gov (United States)

    Mathai, Varghese; Thiang, Guo Chuan

    2016-07-01

    Recently, we introduced T-duality in the study of topological insulators. In this paper, we study the bulk-boundary correspondence for three phenomena in condensed matter physics, namely, the quantum Hall effect, the Chern insulator, and time reversal invariant topological insulators. In all of these cases, we show that T-duality trivializes the bulk-boundary correspondence.

  8. 7 CFR 58.211 - Packaging room for bulk products.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Packaging room for bulk products. 58.211 Section 58... Service 1 Rooms and Compartments § 58.211 Packaging room for bulk products. A separate room or area shall... dust within the packaging room and where needed, a dust collector shall be provided and...

  9. Advanced and new developments in bulk metal forming

    DEFF Research Database (Denmark)

    Bay, Niels; Wanheim, Tarras; Ravn, Bjarne Gottlieb;

    2000-01-01

    Increasing demands to manufacturing industry of faster, better and cheaper production has intensified the research and development of bulk metal forming. The present paper gives examples on European industrial research on secondary bulk metal forming processes. The R&D follows three lines of appr...

  10. Import and Export of Bulk Pharmaceuticals in 2006

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ According to customs statistics, the total import and export value of bulk pharmaceuticals (excluding chemical raw materials and bulk pesticides) in China was US$10.346 billion in 2006. The export value was US$7.482 billion - an increase of 22% over the 2005.

  11. Calculation of structurally related properties of bulk and surface Si

    International Nuclear Information System (INIS)

    The self-consistent pseudopotential method is applied to study the bulk and surface structurally related properties of Si. Equilibrium configurations are determined by minimizing the total energy of the system; the calculated bulk properties and the surface relaxation of Si are found to be in good agreement with experiment. The surface energy and the surface reconstruction of Si are briefly discussed

  12. 27 CFR 24.301 - Bulk still wine record.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bulk still wine record. 24..., DEPARTMENT OF THE TREASURY LIQUORS WINE Records and Reports § 24.301 Bulk still wine record. A proprietor who produces or receives still wine in bond, (including wine intended for use as distilling material or...

  13. 77 FR 12293 - PCBs Bulk Product v. Remediation Waste

    Science.gov (United States)

    2012-02-29

    ... AGENCY PCBs Bulk Product v. Remediation Waste AGENCY: Environmental Protection Agency (EPA). ACTION... remediation waste. The proposed reinterpretation is ] in response to questions EPA received about the... regarding PCB bulk product and PCB remediation waste under regulations promulgated at 40 CFR part 761....

  14. Optimized geometry for bulk coal PGNAA with external moderation of the source neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, C.; Salgado, J.; Carvalho, F.G. [Nuclear and Technical Inst., Sacavem (Portugal). Dept. of Physics

    1995-10-01

    A simulation study of a PGNAA system for the analysis of coal with a {sup 252}Cf neutron source has been carried out using the MCNP code to investigate the effect on the system response of variable thickness, density and composition of the sample when the source is placed at the center of a moderating sphere of polyethylene. Results for different radii of the moderating sphere are reported. The results show that the geometry of the measuring arrangement can be chosen so that the {gamma} count rate/wt% of an arbitrary element (including hydrogen) is independent both of the hydrogen content of the coal, {omega}{sub H}, expressed as a mass fraction, and of the bulk density, d, or volume hydrogen content of the sample {nu}{sub H}, at least in the range of {omega}{sub H}-values commonly found in bituminous coals. The system response, defined as the magnitude of the output signal/wt% of an arbitrary element in the coal composition is then independent of composition and bulk density of the coal sample. (author).

  15. Optimized geometry for bulk coal PGNAA with external moderation of the source neutrons

    Science.gov (United States)

    Oliveira, C.; Salgado, J.; Carvalho, F. G.

    1995-10-01

    A simulation study of a PGNAA system for the analysis of coal with a 252Cf neutron source has been carried out using the MCNP code to investigate the effect on the system response of variable thickness, density and composition of the sample when the source is placed at the center of a moderating sphere of polyethylene. Results for different radii of the moderating sphere are reported. The results show that the geometry of the measuring arrangement can be chosen so that the γ count rate/wt % of an arbitrary element (including hydrogen) is independent both of the hydrogen content of the coal, ωH, expressed as a mass fraction, and of the bulk density, d, or volume hydrogen content of the sample νH, at least in the range of ωH-values commonly found in bituminous coals. The system response, defined as the magnitude of the output signal/wt % of an arbitrary element in the coal composition is then independent of composition and bulk density of the coal sample.

  16. Carbon nanotubes grown on bulk materials and methods for fabrication

    Science.gov (United States)

    Menchhofer, Paul A.; Montgomery, Frederick C.; Baker, Frederick S.

    2011-11-08

    Disclosed are structures formed as bulk support media having carbon nanotubes formed therewith. The bulk support media may comprise fibers or particles and the fibers or particles may be formed from such materials as quartz, carbon, or activated carbon. Metal catalyst species are formed adjacent the surfaces of the bulk support material, and carbon nanotubes are grown adjacent the surfaces of the metal catalyst species. Methods employ metal salt solutions that may comprise iron salts such as iron chloride, aluminum salts such as aluminum chloride, or nickel salts such as nickel chloride. Carbon nanotubes may be separated from the carbon-based bulk support media and the metal catalyst species by using concentrated acids to oxidize the carbon-based bulk support media and the metal catalyst species.

  17. Bulk viscosity of spin-one color superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Sa' d, Basil A.

    2009-08-27

    The bulk viscosity of several quark matter phases is calculated. It is found that the effect of color superconductivity is not trivial, it may suppress, or enhance the bulk viscosity depending on the critical temperature and the temperature at which the bulk viscosity is calculated. Also, is it found that the effect of neutrino-emitting Urca processes cannot be neglected in the consideration of the bulk viscosity of strange quark matter. The results for the bulk viscosity of strange quark matter are used to calculate the r-mode instability window of quark stars with several possible phases. It is shown that each possible phase has a different structure for the r-mode instability window. (orig.)

  18. Temperature dependence of bulk viscosity in water using acoustic spectroscopy

    CERN Document Server

    Holmes, M J; Povey, M J W

    2010-01-01

    Despite its fundamental role in the dynamics of compressible fluids, bulk viscosity has received little experimental attention and there remains a paucity of measured data. Acoustic spectroscopy provides a robust and accurate approach to measuring this parameter. Working from the Navier-Stokes model of a compressible fluid one can show that the bulk viscosity makes a significant and measurable contribution to the frequency-squared acoustic attenuation. Here we employ this methodology to determine the bulk viscosity of Millipore water over a temperature range of 7 to 50 degrees Celsius. The measured attenuation spectra are consistent with the theoretical predictions, while the bulk viscosity of water is found to be approximately three times larger than its shear counterpart, reinforcing its significance in acoustic propagation. Moreover, our results demonstrate that this technique can be readily and generally applied to fluids to accurately determine their temperature dependent bulk viscosities.

  19. Strain rate sensitivity studies on bulk nanocrystalline aluminium by nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Varam, Sreedevi; Rajulapati, Koteswararao V., E-mail: kvrse@uohyd.ernet.in; Bhanu Sankara Rao, K.

    2014-02-05

    Nanocrystalline aluminium powder synthesized using high energy ball milling process was characterized by X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The studies indicated the powder having an average grain size of ∼42 nm. The consolidation of the powder was carried out by high-pressure compaction using a uni-axial press at room temperature by applying a pressure of 1.5 GPa. The cold compacted bulk sample having a density of ∼98% was subjected to nanoindentation which showed an average hardness and elastic modulus values of 1.67 ± 0.09 GPa and 83 ± 8 GPa respectively at a peak force of 8000 μN and a strain rate of 10{sup −2} s{sup −1}. Achieving good strength along with good ductility is challenging in nanocrystalline metals. When enough sample sizes are not available to measure ductility and other mechanical properties as per ASTM standards, as is the case with nanocrystalline materials, nanoindentation is a very promising technique to evaluate strain rate sensitivity. Strain rate sensitivity is a good measure of ductility and in the present work it is measured by performing indentation at various loads with varying loading rates. Strain rate sensitivity values of 0.024–0.054 are obtained for nanocrystalline Al which are high over conventional coarse grained Al. In addition, Scanning Probe Microscopy (SPM) image of the indent shows that there is some plastically flown region around the indent suggesting that this nanocrystalline aluminium is ductile.

  20. Probability densities and Lévy densities

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler

    For positive Lévy processes (i.e. subordinators) formulae are derived that express the probability density or the distribution function in terms of power series in time t. The applicability of the results to finance and to turbulence is briefly indicated.......For positive Lévy processes (i.e. subordinators) formulae are derived that express the probability density or the distribution function in terms of power series in time t. The applicability of the results to finance and to turbulence is briefly indicated....

  1. Evaluation of bulk and surfaces absorption edge energy of sol-gel-dip-coating SnO2 thin films

    Directory of Open Access Journals (Sweden)

    Emerson Aparecido Floriano

    2010-12-01

    Full Text Available The absorption edge and the bandgap transition of sol-gel-dip-coating SnO2 thin films, deposited on quartz substrates, are evaluated from optical absorption data and temperature dependent photoconductivity spectra. Structural properties of these films help the interpretation of bandgap transition nature, since the obtained nanosized dimensions of crystallites are determinant on dominant growth direction and, thus, absorption energy. Electronic properties of the bulk and (110 and (101 surfaces are also presented, calculated by means of density functional theory applied to periodic calculations at B3LYP hybrid functional level. Experimentally obtained absorption edge is compared to the calculated energy band diagrams of bulk and (110 and (101 surfaces. The overall calculated electronic properties in conjunction with structural and electro-optical experimental data suggest that the nature of the bandgap transition is related to a combined effect of bulk and (101 surface, which presents direct bandgap transition.

  2. Materials process and applications of single grain (RE)-Ba-Cu-O bulk high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Li Beizhan; Zhou Difan; Xu Kun; Hara, Shogo; Tsuzuki, Keita; Miki, Motohiro; Felder, Brice; Deng Zigang [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology (TUMSAT), 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan); Izumi, Mitsuru, E-mail: izumi@kaiyodai.ac.jp [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology (TUMSAT), 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan)

    2012-11-20

    This paper reviews recent advances in the melt process of (RE)-Ba-Cu-O [(RE)BCO, where RE represents a rare earth element] single grain high-temperature superconductors (HTSs), bulks and its applications. The efforts on the improvement of the magnetic flux pinning with employing the top-seeded melt-growth process technique and using a seeded infiltration and growth process are discussed. Which including various chemical doping strategies and controlled pushing effect based on the peritectic reaction of (RE)BCO. The typical experiment results, such as the largest single domain bulk, the clear TEM observations and the significant critical current density, are summarized together with the magnetization techniques. Finally, we highlight the recent prominent progress of HTS bulk applications, including Maglev, flywheel, power device, magnetic drug delivery system and magnetic resonance devices.

  3. Feasibility of introducing ferromagnetic materials to onboard bulk high-Tc superconductors to enhance the performance of present maglev systems

    Science.gov (United States)

    Deng, Zigang; Wang, Jiasu; Zheng, Jun; Zhang, Ya; Wang, Suyu

    2013-02-01

    Performance improvement is a long-term research task for the promotion of practical application of promising high-temperature superconducting (HTS) magnetic levitation (maglev) vehicle technologies. We studied the feasibility to enhance the performance of present HTS Maglev systems by introducing ferromagnetic materials to onboard bulk superconductors. The principle here is to make use of the high magnetic permeability of ferromagnetic materials to alter the flux distribution of the permanent magnet guideway for the enhancement of magnetic field density at the position of the bulk superconductors. Ferromagnetic iron plates were added to the upper surface of bulk superconductors and their geometric and positioning effects on the maglev performance were investigated experimentally. Results show that the guidance performance (stability) was enhanced greatly for a particular setup when compared to the present maglev system which is helpful in the application where large guidance forces are needed such as maglev tracks with high degrees of curves.

  4. Characterization of the influence of polarization orientation on bulk damage in KDP crystals at different wavelengths

    Science.gov (United States)

    Zheng, YinBo; Ding, Lei; Zhou, XinDa; Ba, RongSheng; Yuan, Jing; Xu, HongLei; Na, Jin; Li, YaJun; Yang, XiaoYu; Chai, Liqun; Chen, Bo; Zheng, WanGuo

    2016-08-01

    The investigation of polarization orientation on damage performance of type I doubler KDP crystals under different wavelengths pulses irradiation is presented in this work. Pinpoints densities (PPD) and the size distribution of pinpoints are extracted through light scattering pictures captured by microscope. The obtained results indicate that the measured PPD as a function of the fluence is both wavelength and polarization dependent, although neither fluence nor polarization have impact on the size distribution of pinpoints. We also find that the damage performances can separate into three groups depending on the wavelength, which suggests the existence of different categories of precursors and different mechanisms responsible for bulk damage initiation in SHG KDP crystals.

  5. Approximation for the absorption coefficient of airborne atmospheric aerosol particles in terms of measurable bulk properties

    OpenAIRE

    HÄNEL, GOTTFRIED; Dlugi, Ralph

    2011-01-01

    The absorption coefficient of airborne atmospheric aerosol particles can be approximated by where λ is the wavelength of radiation, n — ik is the mean complex refractive index, ρ the mean bulk density, and M/Vk the mass of the particles per unit volume of air. This approximation gives good results at relative humidities between 0 and 0.95 for the wavelengths of radiation between 0.55 μm and 2.0 μm and between 9.25 μm and 12.0 μm. Basing on this approximation it is possible to determine the s...

  6. CMOS compatible generic batch process towards flexible memory on bulk monocrystalline silicon (100)

    KAUST Repository

    Ghoneim, Mohamed T.

    2014-12-01

    Today\\'s mainstream flexible electronics research is geared towards replacing silicon either totally, by having organic devices on organic substrates, or partially, by transferring inorganic devices onto organic substrates. In this work, we present a pragmatic approach combining the desired flexibility of organic substrates and the ultra-high integration density, inherent in silicon semiconductor industry, to transform bulk/inflexible silicon into an ultra-thin mono-crystalline fabric. We also show the effectiveness of this approach in achieving fully flexible electronic systems. Furthermore, we provide a progress report on fabricating various memory devices on flexible silicon fabric and insights for completely flexible memory modules on silicon fabric.

  7. Inner Structure of Boiling Nucleus and Interfacial Energy Between Nucleus and Bulk Liquid

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Dong; TIAN Yong; PENG Xiao-Feng; WANG Bu-Xuan

    2004-01-01

    @@ A model of two-region structure of a nucleus is proposed to describe nucleus evolution. The interfacial tension between bulk liquid phase and nucleus is dependent on the density gradient in the transition region and varies with the structure change of the transition region. With the interfacial tension calculated using this model, the predicted nucleation rate is very close to the experimental measurement. Furthermore, this model and associated analysis provide solid theoretical evidence to clarify the definition of nucleation rate and understand the nucleation phenomenon with insight into the physical nature.

  8. Silicon carbide nanorodes on SiC bulk substrates: synthesis and field electron emission properties

    International Nuclear Information System (INIS)

    Full text: Earlier, we prepared SiC nanowires by a catalyst-assisted process at elevated temperatures from commercially SiC powders. In the study, silicon carbide (SiC) nanorodes were directly grown on the flat surface of commercially SiC bulk substrates. Their structure and chemical composition were studied by Raman spectroscopy and high-resolution transmission electron microscopy. A transparent anode technique was used to examine the field emission properties of the samples. The total current-voltage characteristics were recorded and a current density of 69.29 mA/cm2 was recorded at a field of 4 MV/m. Ref. 1 (author)

  9. Improved charge transport in P3HT:PCBM bulk heterojunction PV cell under ambient environment

    Energy Technology Data Exchange (ETDEWEB)

    Bell, July T.; Mola, Genene T., E-mail: mola@ukzn.ac.za

    2014-03-15

    Enhanced current density has been observed from P3HT:PCBM bulk heterojunction solar cell after a well sonicated solution was diluted with fresh chloroform solvent. The preparation of the devices was carried out in a simple laboratory environment without glove box and clean room. As the result of such current surge in the devices the efficiency has risen more than double compared to those devices without dilution of the P3HT:PCBM solution. We have recorded an average power conversion efficiency of 4.02(5)% under this condition. This is an encouraging development toward achieving low cost organic photovoltaic devices.

  10. Facile synthesis of tin phosphite nanosheets via exfoliated bulk crystals: Electronic structure and piezoelectric property.

    Science.gov (United States)

    Song, Jun-Ling; Zhang, Xi-Rui; Lu, Rui-Feng

    2016-08-01

    Tin phosphite nanosheets were synthesized by a facile exfoliation method. SnHPO3 nanosheets with a thickness of ∼2.6nm readily form a stable colloidal suspension in ethanol using ultrasonic method. Structures and optical properties of the obtained nanosheets were investigated. The prepared SnHPO3 nanosheets exhibit an obvious blue-shift in UV absorbance compared with bulk SnHPO3 crystal materials. Moreover, the piezoelectric coefficients of SnHPO3 monolayer were calculated based on density functional theory, which are larger than that of h-BN monolayer, indicating this material could be a good candidate for designing electro-optical nano-devices.

  11. Surface and bulk modification of W-La2O3 armor mock-up

    International Nuclear Information System (INIS)

    W-(1%)La2O3 has been investigated after thermal exposure in the Quasi-Stationary Plasma Accelerator facility in order to obtain information regarding its surface damage and morphological modification. The profilometry measurements and the Scanning Electron Microscopy analysis showed that surface erosion and corrugation become more pronounced with increasing the thermal load. The La2O3 particle density inside the sample has been measured by Scanning Auger Microscopy. It decreases with increasing the thermal load and presents a negative gradient from the bulk to the surface.

  12. Ionic charge transport between blockages: Sodium cation conduction in freshly excised bulk brain tissue

    Energy Technology Data Exchange (ETDEWEB)

    Emin, David, E-mail: emin@unm.edu [Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States); Akhtari, Massoud [Semple Institutes for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095 (United States); Ellingson, B. M. [Department of Radiology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095 (United States); Mathern, G. W. [Department of Neurosurgery, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095 (United States)

    2015-08-15

    We analyze the transient-dc and frequency-dependent electrical conductivities between blocking electrodes. We extend this analysis to measurements of ions’ transport in freshly excised bulk samples of human brain tissue whose complex cellular structure produces blockages. The associated ionic charge-carrier density and diffusivity are consistent with local values for sodium cations determined non-invasively in brain tissue by MRI (NMR) and diffusion-MRI (spin-echo NMR). The characteristic separation between blockages, about 450 microns, is very much shorter than that found for sodium-doped gel proxies for brain tissue, >1 cm.

  13. Functional Counterpart of Lagrangian Theorem and Perturbative Density Functional Theory: a Forgotten Idea

    Institute of Scientific and Technical Information of China (English)

    周世琦

    2002-01-01

    In this Letter, we truncate the functional expansion of the non-uniform first-order direct correlation function (DCF) around the bulk density at the lowest order. But the truncation is performed formally and exactly by making use of functional counterpart of the Lagrangian theorem of differential calculus. Consequently the expansion coefficient, i.e. the uniform second-order DCF, is replaced by its non-uniform counterpart whose density argument is an appropriate mixture of calculated density distribution and the bulk density with a mixing parameter determined by a hard-wall sum rule. The non-uniform second-order DCF is then approximated by the uniform second-order DCF with an appropriate weighted density as its density argument. The present formally exact truncated functional expansion predicts the density distribution in good agreement with simulation data for hard sphere and Lennard-Jones fluid exerted by an external field.

  14. Vibrationally-Fluidized Granular Flows: Impact and Bulk Velocity Measurements Compared with Discrete Element and Continuum Models

    Science.gov (United States)

    Hashemnia, Kamyar

    A new laser displacement probe was developed to measure the impact velocities of particles within vibrationally-fluidized beds. The sensor output was also used to measure bulk flow velocity along the probe window and to provide a measure of the media packing. The displacement signals from the laser sensors were analyzed to obtain the probability distribution functions of the impact velocity of the particles. The impact velocity was affected by the orientation of the laser probe relative to the bulk flow velocity, and the density and elastic properties of the granular media. The impact velocities of the particles were largely independent of their bulk flow speed and packing density. Both the local impact and bulk flow velocities within a tub vibratory finisher were predicted using discrete element modelling (DEM) and compared to the measured values for spherical steel media. It was observed that the impact and bulk flow velocities were relatively insensitive to uncertainties in the contact coefficients of friction and restitution. It was concluded that the predicted impact and bulk flow velocities were dependent on the number of layers in the model. Consequently, the final DE model mimicked the key aspects of the experimental setup, including the submerged laser sensor. The DE method predictions of both impact velocity and bulk flow velocity were in reasonable agreement with the experimental measurements, with maximum differences of 20% and 30%, respectively. Discrete element modeling of granular flows is effective, but requires large numerical models. In an effort to reduce computational effort, this work presents a finite element (FE) continuum model of a vibrationally-fluidized granular flow. The constitutive equations governing the continuum model were calibrated using the discrete element method (DEM). The bulk flow behavior of the equivalent continuum media was then studied using both Lagrangian and Eulerian FE formulations. The bulk flow velocities predicted

  15. Density functional theory a practical introduction

    CERN Document Server

    Sholl, David

    2009-01-01

    Demonstrates how anyone in math, science, and engineering can master DFT calculations Density functional theory (DFT) is one of the most frequently used computational tools for studying and predicting the properties of isolated molecules, bulk solids, and material interfaces, including surfaces. Although the theoretical underpinnings of DFT are quite complicated, this book demonstrates that the basic concepts underlying the calculations are simple enough to be understood by anyone with a background in chemistry, physics, engineering, or mathematics. The authors show how the widespread availability of powerful DFT codes makes it possible for students and researchers to apply this important computational technique to a broad range of fundamental and applied problems. Density Functional Theory: A Practical Introduction offers a concise, easy-to-follow introduction to the key concepts and practical applications of DFT, focusing on plane-wave DFT. The authors have many years of experience introducing DFT to studen...

  16. Anisotropic dynamic mass density for fluidsolid composites

    KAUST Repository

    Wu, Ying

    2012-10-01

    By taking the low frequency limit of multiple-scattering theory, we obtain the dynamic effective mass density of fluidsolid composites with a two-dimensional rectangular lattice structure. The anisotropic mass density can be described by an angle-dependent dipole solution, to the leading-order of solid concentration. The angular dependence vanishes for the square lattice, but at high solid concentrations there is a structure-dependent factor that contributes to the leading-order solution. In all cases, Woods formula is found to be accurately valid for the effective bulk modulus, independent of the structures. Numerical evaluations from the solutions are shown to be in excellent agreement with finite-element simulations. © 2012 Elsevier B.V.

  17. Optimization and Performance Analysis of Bulk-Driven Differential Amplifier

    Directory of Open Access Journals (Sweden)

    Antarpreet kaur

    2014-04-01

    Full Text Available In recent years, there has been an increasing demand for high-speed digital circuits at low power consumption. This paper presents a design of input stage of Operational Amplifier i.e cascode differential amplifier using a standard 65nm CMOS Technology.A comparison betweem gate-driven, bulk-driven and cascode bulk driven bulk-driven differential amplifier is described. The Results demonstrate that CMMR is 83.98 dB, 3-dB Bandwidth is 1.04 MHz. The circuit dissipate power of 28uWunder single supply of 1.0V.

  18. Engineering nanostructural routes for enhancing thermoelectric performance: bulk to nanoscale

    Directory of Open Access Journals (Sweden)

    Rajeshkumar eMohanraman

    2015-11-01

    Full Text Available Thermoelectricity is a very important physical property, especially its significance in heat-electricity conversion. If thermoelectric devices can be effectively applied to the recovery of the renewable energies, such as waste heat and solar energy, the energy shortage and global warming issues may be greatly relieved. This review focusses recent developments on the thermoelectric performance of a low-dimensional material, bulk nanostructured materials, conventional bulk materials etc. Particular emphasis is given on, how the nanostructure in nanostructured composites, confinement effects in one-dimensional nanowires and doping effects in conventional bulk composites plays an important role in ZT enhancement.

  19. Bulk sound velocity of porous materials at high pressures

    Institute of Scientific and Technical Information of China (English)

    耿华运; 吴强; 谭华; 蔡灵仓; 经福谦

    2002-01-01

    A correction of Walsh's method for bulk sound velocity calculation for shocked porous materials is accomplishedbased on the Wu-Jing thermodynamic equation of state. The corrected bulk velocities for solid and porous sampleswith low porosities are in good agreement with the corresponding experimental data published previously. On the basisof this corrected equation, the influence of thermoelectrons on the bulk velocity of shocked materials is discussed indetail at pressures of 50, 70 and 200 GPa. Some interesting phenomena are revealed, which seem to be the uniquefeatures of a dynamic-pressure-loading process and could not be found in static experiments.

  20. Alternative technology of nanoparticles consolidation in the bulk material

    Directory of Open Access Journals (Sweden)

    VOLKOV Georgiy Michailovich

    2016-02-01

    Full Text Available Theoretical bases and technological principles of single-stages nanoparticles conso-lidation into bulk material were offered. The theory was implemented on the model system of carbon-carbon in the process of high-temperature pyrolysis of hydrocar-bons. The bulk carbon nanomaterial with unique technical properties was produced. That made it possible to create engineering products which technical characteristics are higher than the existing level in the world. The proposed theory can be adapted to other gas-phase, liquid phase and secondary crystallization processes to create bulk nanomaterials of another chemical composition with no less unique properties.

  1. Bulk Local States and Crosscaps in Holographic CFT

    CERN Document Server

    Nakayama, Yu

    2016-01-01

    In a weakly coupled gravity theory in the anti-de Sitter space, local states in the bulk are linear superpositions of Ishibashi states for a crosscap in the dual conformal field theory. The superposition structure can be constrained either by the microscopic causality in the bulk gravity or the bootstrap condition in the boundary conformal field theory. We show, contrary to some expectation, that these two conditions are not compatible to each other in the weak gravity regime. We also present an evidence to show that bulk local states in three dimensions are not organized by the Virasoro symmetry.

  2. Unipolar memristive switching in bulk positive temperature coefficient ceramic thermistor

    Science.gov (United States)

    Wu, Hongya; Wang, Caihui; Fu, Hua; Zhou, Ji; Zheng, Shuzhi

    2016-01-01

    A memristive switching phenomena was investigated in macroscale bulk positive temperature coefficient (PTC) thermosensitive ceramics. (BaxSr1-x)TiO3, which is a well-known PTC thermistor, was taken as an example to analyze the memristive behavior of those macroscale bulk ceramics. Hysteretic current-voltage (I-V) characteristics, which are the features of memristor were obtained. The origin of the effect is attributed to the PTC thermosensitive characteristic of the bulk ceramics, and a switching mechanism driven by competing field-driven heat generation and heat dissipation was proposed.

  3. Spontaneous localization of bulk fields: the six-dimensional case

    International Nuclear Information System (INIS)

    We study N=2 supersymmetric gauge theories with d=6 bulk and d=4 brane fields charged under a U(1) gauge symmetry. Radiatively induced Fayet-Iliopoulos terms lead to an instability of the bulk fields. We compute the profile of the bulk zero modes and observe the phenomenon of spontaneous localization towards the position of the branes. While this mechanism is quite similar to the d=5 case, the mass spectrum of the excited Kaluza-Klein modes shows a crucial difference

  4. Negative Effects of Sludge Bulking in Membrane Bio-Reactor

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ying; HUANG Zhi; REN Nanqi; MENG Qingjuan

    2006-01-01

    Sludge bulking property of membrane bio-reactor was investigated in this study through contrast research. When the sludge bulking appeared, the removal efficiency of COD in membrane bio-reactor increased slightly through the function of filamentous bacteria. However, the negative effects of the higher net water-head differential pressures, the high block rate of membrane pore and the great quantity of filamentous bacteria at the external surface presented at the same time. Thus, plenty of methods should be performed to control sludge bulking once it happened in membrane bio-reactor.

  5. Eco Issues in Bulk Materials Handling Technologies in Ports

    Directory of Open Access Journals (Sweden)

    Nenad Zrnić

    2011-09-01

    Full Text Available This paper deals with eco issues in bulk materials handling in ports. Solid, free-flowing materials are said to be in bulk. Bulk materials handling is very difficult, because it incorporates all the features of liquids, gasses and mass solids. Energy efficiency, dust emissions in nearby environment, dust explosions, jamming, noise, handling of hazardous materials and protection of materials from contamination are issues that will be considered in this paper. Here are also presented possible solutions for some of these issues

  6. Engineering Nanostructural Routes for Enhancing Thermoelectric Performance: Bulk to Nanoscale

    Science.gov (United States)

    Mohanraman, Rajeshkumar; Lan, Tian-Wey; Hsiung, Te-Chih; Amada, Dedi; Lee, Ping-Chung; Ou, Min-Nan; Chen, Yang-Yuan

    2015-01-01

    Thermoelectricity is a very important phenomenon, especially its significance in heat-electricity conversion. If thermoelectric devices can be effectively applied to the recovery of the renewable energies, such as waste heat and solar energy, the energy shortage, and global warming issues may be greatly relieved. This review focusses recent developments on the thermoelectric performance of a low-dimensional material, bulk nanostructured materials, conventional bulk materials etc. Particular emphasis is given on, how the nanostructure in nanostructured composites, confinement effects in one-dimensional nanowires and doping effects in conventional bulk composites plays an important role in ZT enhancement. PMID:26913280

  7. Basin Excavation, Lower Crust, Composition, and Bulk Moon Mass balance in Light of a Thin Crust

    Science.gov (United States)

    Jolliff, B. L.; Korotev, R. L.; Ziegler, R. A.

    2013-01-01

    New lunar gravity results from GRAIL have been interpreted to reflect an overall thin and low-density lunar crust. Accordingly, crustal thickness has been modeled as ranging from 0 to 60 km, with thinnest crust at the locations of Crisium and Moscoviense basins and thickest crust in the central farside highlands. The thin crust has cosmochemical significance, namely in terms of implications for the Moon s bulk composition, especially refractory lithophile elements that are strongly concentrated in the crust. Wieczorek et al. concluded that the bulk Moon need not be enriched compared to Earth in refractory lithophile elements such as Al. Less Al in the crust means less Al has been extracted from the mantle, permitting relatively low bulk lunar mantle Al contents and low pre- and post-crust-extraction values for the mantle (or the upper mantle if only the upper mantle underwent LMO melting). Simple mass-balance calculations using the method of [4] suggests that the same conclusion might hold for Th and the entire suite of refractory lithophile elements that are incompatible in olivine and pyroxene, including the KREEP elements, that are likewise concentrated in the crust.

  8. Bulk coolant cavitation in LMFBR containment loading following a whole-core explosion

    International Nuclear Information System (INIS)

    An LMFBR core undergoing an explosion transmits energy to the containment in a series of pressure waves and the containment loading is determined by their cumulative effect. These pressure waves are modified by their interaction with the coolant through which they propagate. It is necessary to model both the induction of bulk cavitation by tension waves and the interaction of pressure waves with cavitated liquid in realistic containment loading calculations. This paper sets out the progress which has been achieved in such modelling and first indications for the effect of bulk coolant cavitation in LMFBR containment loading. Conclusions may be briefly summarised: 1) Bulk cavitation must be included in realistic containment loading calculations. 2) Phenomenological models of cavitated liquid without memory are inappropriate. The best approach is to model bubble dynamics directly, including at least momentum conservation and surface tension. 3) The containment loading resulting from a given explosion is sensitive to the state of preparation of the coolant. The number density of nucleation sites should therfore accompany the results of model tests. (Auth.)

  9. Pillar Initiated Growth of High Indium Content Bulk Indium Gallium Nitride to Improve the Material Quality for Photonic Devices

    Science.gov (United States)

    McFelea, Heather Dale

    The goal of this research was to reduce dislocations and strain in high indium content bulk InGaN to improve quality for optical devices. In an attempt to achieve this goal, InGaN pillars were grown with compositions that matched the composition of the bulk InGaN grown on top. Pillar height and density were optimized to facilitate coalescence on top of the pillars. It was expected that dislocations within the pillars would bend to side facets, thereby reducing the dislocation density in the bulk overgrowth, however this was not observed. It was also expected that pillars would be completely relaxed at the interface with the substrate. It was shown that pillars are mostly relaxed, but not completely. Mechanisms are proposed to explain why threading dislocations did not bend and how complete relaxation may have been achieved by mechanisms outside of interfacial misfit dislocation formation. Phase separation was not observed by TEM but may be related to the limitations of the sample or measurements. High indium observed at facets and stacking faults could be related to the extra photoluminescence peaks measured. This research focused on the InGaN pillars and first stages of coalescence on top of the pillars, saving bulk growth and device optimization for future research.

  10. Ab-initio investigation of structural, electronic and optical properties BSb compound in bulk and surface (110 states

    Directory of Open Access Journals (Sweden)

    H A Badehian

    2015-07-01

    Full Text Available In recent work the structural, electronic and optical properties of BSb compound in bulk and surface (110 states have been studied. Calculations have been performed using Full-Potential Augmented Plane Wave (FP-LAPW method by WIEN2k code in Density Functional Theory (DFT framework. The structural properties of the bulk such as lattice constant, bulk module and elastic constants have been investigated using four different approximations. The band gap energy of the bulk and the (110 surface of BSb were obtained about 1.082 and 0.38 eV respectively. Moreover the surface energy, the work function, the surface relaxation, surface state and the band structure of BSb (110 were investigated using symmetric and stoichiometric 15 layers slabs with the vacuum of 20 Bohr. In addition, the real and imaginary parts of the dielectric function of the bulk and the BSb (110 slab were calculated and compared to each other. Our obtained results have a good agreement with the available results.

  11. Trapped magnetic field of a superconducting bulk magnet in high- T sub c RE-Ba-Cu-O

    CERN Document Server

    Fujimoto, H; Higuchi, T; Nakamura, Y; Kamijo, H; Nagashima, K; Murakami, M

    1999-01-01

    Superconducting magnets made of high-T sub c superconductors are promising for industrial applications. It is well known that REBa sub 2 Cu sub 3 O sub 7 sub - sub x and LRE (light rare-earth) Ba sub 2 Cu sub 3 O sub 7 sub - sub x superconductors prepared by melt processes have a high critical current density, J sub c , at 77 K and high magnetic fields. Therefore, the materials are very prospective for high magnetic field application as a superconducting permanent/bulk magnet with liquid-nitrogen refrigeration. LREBaCuO bulks, compared with REBaCuO bulks, exhibit a larger J sub c in high magnetic fields and a much improved irreversibility field, H sub i sub r sub r , at 77 K. In this study, we discuss the possibility and trapped field properties of a superconducting bulk magnet, as well as the melt processing for bulk superconductors and their characteristic superconducting properties. One of the applications is a superconducting magnet for the future magnetically levitated (Maglev) train.

  12. Effect of silver addition on the mechanical and field trapping properties of Gd-Ba-Cu-O bulk superconductors

    CERN Document Server

    Nariki, S; Matsui, M; Murakami, M

    2002-01-01

    The effect of Ag addition on the microstructure and the mechanical and field trapping properties of Gd-Ba-Cu-O bulk superconductor has been investigated. The single grain Gd-Ba-Cu-O bulk superconductors 32 mm in diameter were fabricated with 0-30 mass%Ag/sub 2/O additions by the melt growth method under controlled oxygen partial pressure of 1.0%. From microscopic observations, it was found that the macro- cracks in the a-b plane decreased with Ag addition. The three-point bending test showed that the average strength of Ag-free bulk was 69 MPa at room temperature, while the strength was dramatically improved to 110-115 MPa with 10-30 mass%Ag/sub 2/O additions. The trapped magnetic field of Ag-free bulk sample was 1.3 T at 77 K. The trapped field of bulk Gd-Ba-Cu-O samples with 10-20 mass%Ag/sub 2/O exhibited high values of 1.8-2.0 T at 77 K. However, the trapped field of the sample with 30 mass%Ag/sub 2/O addition was lowered to 1.1 T with decreasing the critical current density. The trapped field of Ag- adde...

  13. Levitation performance of the magnetized bulk high-T{sub c} superconducting magnet with different trapped fields

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W. [Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), Chengdu, Sichuan 610031 (China); State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); National Laboratory of Rail Transit, Chengdu, Sichuan 610031 (China); Wang, J.S., E-mail: tonny@mars.swjtu.edu.c [Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), Chengdu, Sichuan 610031 (China); National Laboratory of Rail Transit, Chengdu, Sichuan 610031 (China); Liao, X.L.; Zheng, S.J.; Ma, G.T.; Zheng, J. [Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), Chengdu, Sichuan 610031 (China); State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); National Laboratory of Rail Transit, Chengdu, Sichuan 610031 (China); Wang, S.Y. [Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), Chengdu, Sichuan 610031 (China); National Laboratory of Rail Transit, Chengdu, Sichuan 610031 (China)

    2011-03-15

    Research highlights: {yields} The different trapped fields bring entirely different levitation performance. {yields} The force relaxation characters is directly bound up with the trapped field. {yields} The higher trapped field not means better levitation performance. {yields} An profitable internal induced current configuration will benefit to suppress flux motion. - Abstract: To a high-T{sub c} superconducting (HTS) maglev system which needs large levitation force density, the magnetized bulk high-T{sub c} superconductor (HTSC) magnet is a good candidate because it can supply additional repulsive or attractive force above a permanent magnet guideway (PMG). Because the induced supercurrent within a magnetized bulk HTSC is the key parameter for the levitation performance, and it is sensitive to the magnetizing process and field, so the magnetized bulk HTSC magnets with different magnetizing processes had various levitation performances, not only the force magnitude, but also its force relaxation characteristics. Furthermore, the distribution and configuration of the induced supercurrent are also important factor to decide the levitation performance, especially the force relaxation characteristics. This article experimentally investigates the influences of different magnetizing processes and trapped fields on the levitation performance of a magnetized bulk HTSC magnet with smaller size than the magnetic inter-pole distance of PMG, and the obtained results are qualitatively analyzed by the Critical State Model. The test results and analyses of this article are useful for the suitable choice and optimal design of magnetized bulk HTSC magnets.

  14. Density functional theory study of UO2

    International Nuclear Information System (INIS)

    Uranium dioxide (UO2) is an important fuel material for nuclear industry, but the electronic structure of 5f electrons of uranium has not been reliably described so far. The interpretation of some of experimental results is still controversial because of a large variety of unusual electronic effects originating from strong Coulomb repulsion between 5f electrons of uranium. During irradiation, UO2 undergo nuclear fission and the noble gas Xe is formed. Xe diffuses into the gap between the cladding and pellets of the fuel, and causes swelling of the fuel. Point defects are thought to be the major channel of Xe diffusion in UO2. Therefore, it is important to investigate defects in order to understand the diffusion mechanism in nuclear reactor. We present the density functional theory (DFT) calculations on UO2 employing the local spin density approximation (LSDA) + U method. First, we calculated the chemical and physical properties of bulk UO2 such as the lattice constant, bulk modulus, cohesive energy, magnetic moment, and band gap. We compared the calculated results with available experimented data. Then we performed supercell calculations to investigate the structure of different defects in UO2, the defect formation energy, and the defect-induced changes in the electronic structure

  15. Optimization of processing conditions towards high trapped fields in MgB{sub 2} bulks

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, M., E-mail: miryala1@shibaura-it.ac.jp [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Inoue, K. [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Koblischka, M.R. [Experimental Physics, Saarland University, Campus C 6 3, 66123 Saarbrücken (Germany); Tomita, M. [Railway Technical Research Institute, 2-8-38 Hikari-cho, Kokubunji-shi, Tokyo 185-8540 (Japan); Murakami, M. [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan)

    2014-09-01

    Highlights: • Bulk MgB{sub 2} samples were prepared via solid state reaction at various sintering temperatures. • The J{sub c} value at 10 K and 0 T was 2.60 × 10{sup 5} A/cm{sup 2}. • A pinning force analysis for the samples sintered at 775 °C revealed a non-scaling behavior. • The trapped field results showed that processing temperature is the key to improving TF values. - Abstract: The present investigation focuses on the effects of various sintering temperatures on the critical current densities and the trapped field values of disk-shaped bulk MgB{sub 2} superconductors fabricated with a simple solid state reaction. The samples were prepared by varying the sintering temperature from 750 to 950 °C in pure Ar atmosphere. Scanning electron microscopy (SEM) and X-ray diffraction analyses showed that single phase and homogenous MgB{sub 2} bulks are produced in using sintering temperatures in the range of 750–825 °C. The samples sintered at 775 °C showed the highest critical current density (J{sub c}) values of 250 kA/cm{sup 2} at 10 K and 181 kA/cm{sup 2} at 20 K in self field. We also measured the trapped field values at 20 K for bulk MgB{sub 2} samples 20 mm in diameter and 7 mm in thickness, sintered at temperatures in the range of 700–950 °C with the same sintering duration of 3 h. Almost all the samples exhibited the trapped field values higher than 1 T, which shows the high potential of sintered MgB{sub 2} bulk materials as trapped field magnets. The highest value of 1.51 T at 20 K was achieved in the MgB{sub 2} sample sintered at 775 °C, reflecting its high pinning performance and homogeneous microstructure.

  16. Determination of doping effects on Si and GaAs bulk samples properties by photothermal investigations

    International Nuclear Information System (INIS)

    The knowledge of doping effects on optical and thermal properties of semiconductors is crucial for the development of opto-electronic compounds. The purpose of this work is to investigate these effects by mirage effect technique and spectroscopic ellipsometry SE. The near gap optical spectra are obtained from photothermal signal for differently doped Si and GaAs bulk samples. However, the above bandgap absorption is determined from SE. These spectra show that absorption in the near IR increases with dopant density and also the bandgap shifts toward low energies. This behavior is due to free carrier absorption which could be obtained by subtracting phonon-assisted absorption from the measured spectrum. This carrier absorption is related to the dopant density through a semi-empirical model. We have also used the photothermal signal phase to measure the influence of doping on thermal diffusivity

  17. Determination of doping effects on Si and GaAs bulk samples properties by photothermal investigations

    Energy Technology Data Exchange (ETDEWEB)

    Abroug, Sameh [Photothermal Laboratory, IPEIN, BP.62, Merazka 8000, Nabeul (Tunisia); Saadallah, Faycel [Photothermal Laboratory, IPEIN, BP.62, Merazka 8000, Nabeul (Tunisia)], E-mail: Faycel1@yahoo.fr; Yacoubi, Noureddine [Photothermal Laboratory, IPEIN, BP.62, Merazka 8000, Nabeul (Tunisia)

    2007-11-15

    The knowledge of doping effects on optical and thermal properties of semiconductors is crucial for the development of opto-electronic compounds. The purpose of this work is to investigate these effects by mirage effect technique and spectroscopic ellipsometry SE. The near gap optical spectra are obtained from photothermal signal for differently doped Si and GaAs bulk samples. However, the above bandgap absorption is determined from SE. These spectra show that absorption in the near IR increases with dopant density and also the bandgap shifts toward low energies. This behavior is due to free carrier absorption which could be obtained by subtracting phonon-assisted absorption from the measured spectrum. This carrier absorption is related to the dopant density through a semi-empirical model. We have also used the photothermal signal phase to measure the influence of doping on thermal diffusivity.

  18. Influence of thermochemical treatments on TSMG YBCO bulks doped with Li and Al

    International Nuclear Information System (INIS)

    The influence of post-growth thermochemical treatments on the transition temperature and the field dependence of the critical current density at 77 K were studied in Y1.5Ba2(Cu,M)3Oy, for M = Li, and Al, bulk superconductors with CeO2 additions prepared by the Top-Seeded Melt-Growth (TSMG) process. The Li and Al dopants react in an opposite way during pre-annealing in an atmosphere with low and high oxygen partial pressure and this behaviour can be associated with the formation and dissolution of dopant clusters. High pressure high temperature oxygenation preserves the peak effect introduced by the dopants and leads to the elimination of oxygenation cracks and consequently to significant increases in the effective critical current density.

  19. Adaptive kernel density estimation

    OpenAIRE

    Philippe Van Kerm

    2003-01-01

    This insert describes the module akdensity. akdensity extends the official kdensity that estimates density functions by the kernel method. The extensions are of two types: akdensity allows the use of an "adaptive kernel" approach with varying, rather than fixed, bandwidths; and akdensity estimates pointwise variability bands around the estimated density functions. Copyright 2003 by Stata Corporation.

  20. MEASUREMENT OF WHEAT DENSITY

    Institute of Scientific and Technical Information of China (English)

    冯跟胜; 党金春; 等

    1995-01-01

    A method used for on line determining the change of wheat density with a automatic watering machine in a lqarge flour mill has been studied.The results show that the higher distinguishing ability is obtained when using 241Am as a γ-ray source for measuring the wheat density than using 137Cs.