WorldWideScience

Sample records for ps-rich phase size

  1. Size-driven quantum phase transitions.

    Science.gov (United States)

    Bausch, Johannes; Cubitt, Toby S; Lucia, Angelo; Perez-Garcia, David; Wolf, Michael M

    2018-01-02

    Can the properties of the thermodynamic limit of a many-body quantum system be extrapolated by analyzing a sequence of finite-size cases? We present models for which such an approach gives completely misleading results: translationally invariant, local Hamiltonians on a square lattice with open boundary conditions and constant spectral gap, which have a classical product ground state for all system sizes smaller than a particular threshold size, but a ground state with topological degeneracy for all system sizes larger than this threshold. Starting from a minimal case with spins of dimension 6 and threshold lattice size [Formula: see text], we show that the latter grows faster than any computable function with increasing local spin dimension. The resulting effect may be viewed as a unique type of quantum phase transition that is driven by the size of the system rather than by an external field or coupling strength. We prove that the construction is thermally robust, showing that these effects are in principle accessible to experimental observation.

  2. Contribution of growth phases to adult size.

    Science.gov (United States)

    Sheehy, A; Gasser, T; Molinari, L; Largo, R H

    2000-01-01

    Based on the data of the First Zurich Longitudinal Growth Study we investigate how interindividual differences in adult size arise in the variables leg height, sitting height and standing height, arm length, bi-iliac width and bihumeral width. Specifically, we are also interested in the question of whether across sexes and variables the same growth phases and the same parameters are predictive for achieving a certain adult size. A rather complex pattern emerges, demonstrating that regulation of growth is not the same for boys and girls and moreover is not the same for the six anthropometric variables studied. Prepubertal growth is characterized by its intensity (average velocity) and by its duration. Whereas duration has by itself no appreciable influence on adult size, prepubertal intensity determines adult size to a high degree across all variables and both sexes. The intensity of prepubertal growth determines adult size to a larger degree for boys than for girls. For a given size at the end of the prepubertal period, a small duration enhances the chance of obtaining a large adult size. Compared with prepubertal growth, the amount of variance of adult size explained is small for pubertal parameters, and--with respect to linear measures--significant for girls only. A small duration of prepubertal growth is in the following mainly compensated by a stronger pubertal spurt (PS), to a varying degree across variables. The overall picture which emerges indicates that sitting height--and to a lesser extent bihumeral width--develop in a more irregular fashion than the variables bi-iliac width and leg height.

  3. Experimental Phase Functions of Millimeter-sized Cosmic Dust Grains

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, O.; Moreno, F.; Guirado, D.; Escobar-Cerezo, J. [Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Vargas-Martín, F. [Department of Electromagnetism and Electronics, University of Murcia, E-30100 Murcia (Spain); Min, M. [SRON Netherlands Institute for Space Research, Sobornnelaan 2, 3584 CA Utrecht (Netherlands); Hovenier, J. W. [Astronomical Institute “Anton Pannekoek,” University of Amsterdam, Science Park 904, 1098 XH, Amsterdam (Netherlands)

    2017-09-01

    We present the experimental phase functions of three types of millimeter-sized dust grains consisting of enstatite, quartz, and volcanic material from Mount Etna, respectively. The three grains present similar sizes but different absorbing properties. The measurements are performed at 527 nm covering the scattering angle range from 3° to 170°. The measured phase functions show two well-defined regions: (i) soft forward peaks and (ii) a continuous increase with the scattering angle at side- and back-scattering regions. This behavior at side- and back-scattering regions is in agreement with the observed phase functions of the Fomalhaut and HR 4796A dust rings. Further computations and measurements (including polarization) for millimeter-sized grains are needed to draw some conclusions about the fluffy or compact structure of the dust grains.

  4. Size dependence of phase transitions in aerosol nanoparticles

    Science.gov (United States)

    Cheng, Yafang; Su, Hang; Koop, Thomas; Mikhailov, Eugene; Pöschl, Ulrich

    2015-04-01

    Phase transitions of nanoparticles are of fundamental importance in atmospheric sciences. Current understanding is insufficient to explain observations at the nano-scale. In particular, discrepancies exist between observations and model predictions of deliquescence and efflorescence transitions and the hygroscopic growth of salt nanoparticles. Here we show that these discrepancies can be resolved by consideration of particle size effects with consistent thermodynamic data. We present a new method for the determination of water and solute activities and interfacial energies in highly supersaturated aqueous solution droplets. Our analysis reveals that particle size can strongly alter the characteristic concentration of phase separation in mixed systems, resembling the influence of temperature. Due to similar effects, atmospheric secondary organic aerosol particles at room temperature are expected to be always liquid at diameters below ~20 nm. We thus propose and demonstrate that particle size should be included as an additional dimension in the equilibrium phase diagram of aerosol nanoparticles. Reference: Cheng, Y. et al. Size dependence of phase transitions in aerosol nanoparticles. Nature Communications. 5:5923 doi: 10.1038/ncomms6850 (2015).

  5. Size dependence of phase transitions in aerosol nanoparticles

    OpenAIRE

    Cheng, Yafang; Su, Hang; Koop, Thomas; Mikhailov, Eugene; P?schl, Ulrich

    2015-01-01

    Phase transitions of nanoparticles are of fundamental importance in atmospheric sciences, but current understanding is insufficient to explain observations at the nano-scale. In particular, discrepancies exist between observations and model predictions of deliquescence and efflorescence transitions and the hygroscopic growth of salt nanoparticles. Here we show that these discrepancies can be resolved by consideration of particle size effects with consistent thermodynamic data. We present a ne...

  6. Two-phase equilibrium states in individual Cu-Ni nanoparticles: size, depletion and hysteresis effects.

    Science.gov (United States)

    Shirinyan, Aram S

    2015-01-01

    In isolated bimetallic nanoscale systems the limit amount of matter and surface-induced size effects can change the thermodynamics of first-order phase transformation. In this paper we present theoretical modification of Gibbs free energy concept describing first-order phase transformation of binary alloyed nanoparticles taking into account size effects as well as depletion and hysteresis effects. In such a way the hysteresis in a form of nonsymmetry for forth and back transforming paths takes place; compositional splitting and the loops-like splitted path on the size dependent temperature-composition phase diagram occur. Our calculations for individual Cu-Ni nanoparticle show that one must differentiate the solubility curves and the equilibrium loops (discussed here in term of solidification and melting loops). For the first time we have calculated and present here on the temperature-composition phase diagram the nanomelting loop at the size of 80 nm and the nanosolidification loop at the size of 25 nm for an individual Cu-Ni nanoparticle. So we observe the difference between the size-dependent phase diagram and solubility diagram, between two-phase equilibrium curves and solubility curves; also intersection of nanoliquidus and nanosolidus is available. These findings lead to the necessity to reconsider such basic concepts in materials science as phase diagram and solubility diagram.

  7. Two-phase equilibrium states in individual Cu–Ni nanoparticles: size, depletion and hysteresis effects

    Science.gov (United States)

    2015-01-01

    Summary In isolated bimetallic nanoscale systems the limit amount of matter and surface-induced size effects can change the thermodynamics of first-order phase transformation. In this paper we present theoretical modification of Gibbs free energy concept describing first-order phase transformation of binary alloyed nanoparticles taking into account size effects as well as depletion and hysteresis effects. In such a way the hysteresis in a form of nonsymmetry for forth and back transforming paths takes place; compositional splitting and the loops-like splitted path on the size dependent temperature–composition phase diagram occur. Our calculations for individual Cu–Ni nanoparticle show that one must differentiate the solubility curves and the equilibrium loops (discussed here in term of solidification and melting loops). For the first time we have calculated and present here on the temperature–composition phase diagram the nanomelting loop at the size of 80 nm and the nanosolidification loop at the size of 25 nm for an individual Cu–Ni nanoparticle. So we observe the difference between the size-dependent phase diagram and solubility diagram, between two-phase equilibrium curves and solubility curves; also intersection of nanoliquidus and nanosolidus is available. These findings lead to the necessity to reconsider such basic concepts in materials science as phase diagram and solubility diagram. PMID:26425433

  8. Two-phase equilibrium states in individual Cu–Ni nanoparticles: size, depletion and hysteresis effects

    Directory of Open Access Journals (Sweden)

    Aram S. Shirinyan

    2015-08-01

    Full Text Available In isolated bimetallic nanoscale systems the limit amount of matter and surface-induced size effects can change the thermodynamics of first-order phase transformation. In this paper we present theoretical modification of Gibbs free energy concept describing first-order phase transformation of binary alloyed nanoparticles taking into account size effects as well as depletion and hysteresis effects. In such a way the hysteresis in a form of nonsymmetry for forth and back transforming paths takes place; compositional splitting and the loops-like splitted path on the size dependent temperature–composition phase diagram occur. Our calculations for individual Cu–Ni nanoparticle show that one must differentiate the solubility curves and the equilibrium loops (discussed here in term of solidification and melting loops. For the first time we have calculated and present here on the temperature–composition phase diagram the nanomelting loop at the size of 80 nm and the nanosolidification loop at the size of 25 nm for an individual Cu–Ni nanoparticle. So we observe the difference between the size-dependent phase diagram and solubility diagram, between two-phase equilibrium curves and solubility curves; also intersection of nanoliquidus and nanosolidus is available. These findings lead to the necessity to reconsider such basic concepts in materials science as phase diagram and solubility diagram.

  9. Phase Separation of Binary Charged Particle Systems with Small Size Disparities using a Dusty Plasma.

    Science.gov (United States)

    Killer, Carsten; Bockwoldt, Tim; Schütt, Stefan; Himpel, Michael; Melzer, André; Piel, Alexander

    2016-03-18

    The phase separation in binary mixtures of charged particles has been investigated in a dusty plasma under microgravity on parabolic flights. A method based on the use of fluorescent dust particles was developed that allows us to distinguish between particles of slightly different size. A clear trend towards phase separation even for smallest size (charge) disparities is observed. The diffusion flux is directly measured from the experiment and uphill diffusion coefficients have been determined.

  10. Optimization of finite-size errors in finite-temperature calculations of unordered phases.

    Science.gov (United States)

    Iyer, Deepak; Srednicki, Mark; Rigol, Marcos

    2015-06-01

    It is common knowledge that the microcanonical, canonical, and grand-canonical ensembles are equivalent in thermodynamically large systems. Here, we study finite-size effects in the latter two ensembles. We show that contrary to naive expectations, finite-size errors are exponentially small in grand canonical ensemble calculations of translationally invariant systems in unordered phases at finite temperature. Open boundary conditions and canonical ensemble calculations suffer from finite-size errors that are only polynomially small in the system size. We further show that finite-size effects are generally smallest in numerical linked cluster expansions. Our conclusions are supported by analytical and numerical analyses of classical and quantum systems.

  11. Investigating the Effect of Particle Size on Pulmonary Surfactant Phase Behavior

    Science.gov (United States)

    Kodama, Akihisa T.; Kuo, Chin-Chang; Boatwright, Thomas; Dennin, Michael

    2014-01-01

    We study the impact of the addition of particles of a range of sizes on the phase transition behavior of lung surfactant under compression. Charged particles ranging from micro- to nanoscale are deposited on lung surfactant films in a Langmuir trough. Surface area versus surface pressure isotherms and fluorescent microscope observations are utilized to determine changes in the phase transition behavior. We find that the deposition of particles close to 20 nm in diameter significantly impacts the coexistence of the liquid-condensed phase and liquid-expanded phase. This includes morphological changes of the liquid-condensed domains and the elimination of the squeeze-out phase in isotherms. Finally, a drastic increase of the domain fraction of the liquid-condensed phase can be observed for the deposition of 20-nm particles. As the particle size is increased, we observe a return to normal phase behavior. The net result is the observation of a critical particle size that may impact the functionality of the lung surfactant during respiration. PMID:25296309

  12. Size-dependent and tunable crystallization of GeSbTe phase-change nanoparticles

    Science.gov (United States)

    Chen, Bin; Ten Brink, Gert H.; Palasantzas, George; Kooi, Bart J.

    2016-12-01

    Chalcogenide-based nanostructured phase-change materials (PCMs) are considered promising building blocks for non-volatile memory due to their high write and read speeds, high data-storage density, and low power consumption. Top-down fabrication of PCM nanoparticles (NPs), however, often results in damage and deterioration of their useful properties. Gas-phase condensation based on magnetron sputtering offers an attractive and straightforward solution to continuously down-scale the PCMs into sub-lithographic sizes. Here we unprecedentedly present the size dependence of crystallization for Ge2Sb2Te5 (GST) NPs, whose production is currently highly challenging for chemical synthesis or top-down fabrication. Both amorphous and crystalline NPs have been produced with excellent size and composition control with average diameters varying between 8 and 17 nm. The size-dependent crystallization of these NPs was carefully analyzed through in-situ heating in a transmission electron microscope, where the crystallization temperatures (Tc) decrease when the NPs become smaller. Moreover, methane incorporation has been observed as an effective method to enhance the amorphous phase stability of the NPs. This work therefore elucidates that GST NPs synthesized by gas-phase condensation with tailored properties are promising alternatives in designing phase-change memories constrained by optical lithography limitations.

  13. Microorganism viability influences internal phase droplet size changes during storage in water-in-oil emulsions.

    Science.gov (United States)

    VanderGheynst, Jean S; Guo, Hong-Yun; Cheng, Yu-Shen; Scher, Herbert

    2013-10-01

    Water-in-oil emulsions provide an alternative for long-term stabilization of microorganisms. Maintaining physical stability of the emulsion and cell viability is critical for large-scale application. Water-in-oil (W/O) emulsions were prepared with the biolarvacide Lagenidium giganteum and the green alga Chlorella vulgaris. Physical stability was measured via light scattering measurements of the internal phase droplets and cell viability was measured by plating and enumerating colony forming units. Emulsions were demonstrated to stabilize L. giganteum and C. vulgaris for more than 4 months without refrigeration. Introducing nutrients into the internal phase of W/O emulsions without cells had no significant effect on changes in aqueous phase droplet size dynamics. Internal phase droplet size changes that occurred over time were greater in the presence of cells. Increases in droplet size were correlated with cell death indicating measurement of internal phase droplet size changes may be an approach for monitoring declines in cell viability during storage.

  14. Simultaneous phase and size control of upconversion nanocrystals through lanthanide doping

    KAUST Repository

    Wang, Feng

    2010-02-25

    Doping is a widely applied technological process in materials science that involves incorporating atoms or ions of appropriate elements into host lattices to yield hybrid materials with desirable properties and functions. For nanocrystalline materials, doping is of fundamental importance in stabilizing a specific crystallographic phase, modifying electronic properties, modulating magnetism as well as tuning emission properties. Here we describe a material system in which doping influences the growth process to give simultaneous control over the crystallographic phase, size and optical emission properties of the resulting nanocrystals. We show that NaYF 4 nanocrystals can be rationally tuned in size (down to ten nanometres), phase (cubic or hexagonal) and upconversion emission colour (green to blue) through use of trivalent lanthanide dopant ions introduced at precisely defined concentrations. We use first-principles calculations to confirm that the influence of lanthanide doping on crystal phase and size arises from a strong dependence on the size and dipole polarizability of the substitutional dopant ion. Our results suggest that the doping-induced structural and size transition, demonstrated here in NaYF 4 upconversion nanocrystals, could be extended to other lanthanide-doped nanocrystal systems for applications ranging from luminescent biological labels to volumetric three-dimensional displays. © 2010 Macmillan Publishers Limited. All rights reserved.

  15. The business environment and phases of development of small and medium-sized enterprises

    OpenAIRE

    Wach, Krzysztof

    2006-01-01

    The subject literature distinguishes several factors that determine the establishment, survival , operations and development of micro, small, and medium-sized enterprises in particular regions. In this article, the author presents a classification of these factors in terms of whether they are barriers or stimulators. On this basis, the author explains the influence of regional environment (meso-environment) factors on the development of small and medium-sized enterprises in various phases of ...

  16. Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation.

    Science.gov (United States)

    Shiraiwa, Manabu; Yee, Lindsay D; Schilling, Katherine A; Loza, Christine L; Craven, Jill S; Zuend, Andreas; Ziemann, Paul J; Seinfeld, John H

    2013-07-16

    Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality, and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosols (SOAs). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multigeneration gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface, and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a midexperiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. Although experiments need to be conducted with other SOA precursor hydrocarbons, current results demonstrate coupling between particle-phase chemistry and size distribution dynamics in the formation of SOAs, thereby opening up an avenue for analysis of the SOA formation process.

  17. Deconvolution by finite-size-source effects of x-ray phase-contrast images

    Energy Technology Data Exchange (ETDEWEB)

    De Caro, Liberato; Scattarella, Francesco; Tangaro, Sabina; Pelliccia, Daniele; Giannini, Cinzia; Bottigli, Ubaldo; Bellotti, Roberto [Istituto di Cristallografia, Consiglio Nazionale delle Ricerche (IC-CNR), via Amendola 122/O, I-70125 Bari (Italy) and Istituto Nazionale Fisica Nucleare, Sezione di Bari, via Amendola 173, 70126 Bari (Italy); Istituto Nazionale Fisica Nucleare, Sezione di Bari, via Amendola 173, 70126 Bari (Italy) and Dipartimento Interateneo di Fisica M. Merlin, Universita degli Studi di Bari, via Amendola 173, 70126 Bari (Italy); Istituto Nazionale Fisica Nucleare, Sezione di Bari, via Amendola 173, 70126 Bari (Italy); School of Physics, Monash University, ARC Centre of Excellence for Coherent X-Ray Science, Clayton, Victoria 3800 (Australia); Istituto di Cristallografia, Consiglio Nazionale delle Ricerche (IC-CNR), via Amendola 122/O, I-70125 Bari (Italy) and Istituto Nazionale Fisica Nucleare, Sezione di Bari, via Amendola 173, 70126 Bari (Italy); Dipartimento di Fisica, Universita di Siena, via Roma 56, 53100 Siena (Italy) and Istituto Nazionale Fisica Nucleare, Sezione di Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa (Italy); Istituto Nazionale Fisica Nucleare, Sezione di Bari, via Amendola 173, 70126 Bari (Italy) and Dipartimento Interateneo di Fisica M. Merlin, Universita degli Studi di Bari, via Amendola 173, 70126 Bari (Italy)

    2011-04-15

    Purpose: In the hard x-ray region, the cross sections for the phase shift of low-Z elements are about 1000 times larger than the absorption ones. As a consequence, phase contrast is detectable even when absorption contrast is minimal or absent. Therefore, phase-contrast imaging could become a valid alternative to absorption contrast without delivering high dose to tissue/human body parts. Methods: To enhance the quality of phase-contrast images without increasing the dose, a possible approach could be the partial deconvolution of the finite source size effects by experimental phase-contrast images. The deconvolution procedure, the authors propose, employs the acquisition of two images on a suitable well-known test sample, one in contact and the other in phase-contrast conditions. Both acquired images are used along with a simulated phase-contrast image (obtained from the test sample in ideal conditions of pointlike source illumination) to correctly retrieve the experimental source distribution function. This information allows a generic experimental phase-contrast image, acquired in the same conditions, to be partially deconvolved by finite source size effects. Results: The performed experimental tests indicate that deconvolved images are equivalent to those which would be obtained with a source 40% smaller than the actual size. In turn, this finding is equivalent to an increase of the ''effective'' lateral spatial coherence length. The corresponding quality improvement of the phase-contrast imaging is directly deducible by the presence of many Fresnel fringes, much better visible with respect to the original experimental phase-contrast images. Conclusions: The use of a test standard sample, always possible in every experimental setup, to partially deconvolve the finite-size-source blurring effects shows that higher quality phase-contrast images could be readily available, making easier diagnoses and tissue/sample analyses. The method could give

  18. Quantification of Laves Phase Particle Size in 9CrW Steel

    DEFF Research Database (Denmark)

    Korcakova, Leona; Hald, John; Somers, Marcel A.J.

    2001-01-01

    Tungsten-alloyed martensic 9Cr steels are applied for streamlines of advanced power plants because of their superior creep performance. Tungsten, as the main new alloying element, induces precipitation of intermetallic Laves phase during long-term exposure at service temperatures around 600 C....... The growth and coarsening of Laves phase was investigated for the martensitic 9CrW steel P92 after aging and after creep testing at 600 or 650 C for times up to 59,000 h. For measurement of the size of Laves phase particles, field emission gun scanning electron microscopy (FEGSEM) was used along with image...

  19. Grain Size Dependence of Uniform Elongation in Single-Phase FCC/BCC Metals

    Science.gov (United States)

    Liu, Haiting; Shen, Yao; Ma, Jiawei; Zheng, Pengfei; Zhang, Lei

    2016-09-01

    We studied the dependence of uniform elongation on grain size in the range of submicron to millimeter for single-phase FCC/BCC metals by reviewing recent experimental results and applying crystal plasticity finite element method simulation. In the order of increasing grain size, uniform elongation can be divided into three stages, namely low elongation stage, nearly constant elongation stage, and decreased elongation with large scatters stage. Low elongation stage features a dramatic increase near the critical grain size at the end of the stage, which is primarily attributed to the emergence of dislocation cell size transition from ultrafine to mid-size grain. Other factors can be neglected due to their negligible influence on overall variation trend. In nearly constant elongation stage, uniform elongation remains unchanged at a high level in general. As grain size keeps growing, uniform elongation starts decreasing and becomes scattered upon a certain grain size, indicating the initiation of decreased elongation with large scatters stage. It is shown that the increase is not linear or smooth but rather sharp at the end of low elongation stage, leading to a wider range in nearly constant elongation stage. The grain size dependence of uniform elongation can serve as a guiding principle for designing small uniaxial tensile specimens for mechanical testing, where size effect matters in most cases.

  20. Size-resolved aqueous-phase atmospheric chemistry in a three-dimensional chemical transport model

    Science.gov (United States)

    Fahey, K. M.; Pandis, S. N.

    2003-11-01

    Three-dimensional chemical transport models typically include a bulk description of aqueous-phase atmospheric chemistry. Previously, this bulk description has been shown to be often inadequate in predicting sulfate production. The pH of the bulk mixture does not adequately describe the pH of the typically heterogeneous droplet population found in clouds and fogs. This often leads to an inability of bulk models to predict sulfate production when pH-dependent production pathways are important. A more accurate size-resolved aqueous-phase chemistry model, however, has long been considered infeasible for incorporation in a three-dimensional chemical transport model because of high computational costs. Here we investigate the feasibility of adding a computationally efficient size-resolved aqueous-phase chemistry module (Variable Size Resolution Model (VSRM)) to a three-dimensional model (the latest version of the Comprehensive Air Quality Model with extensions (PMCAMx)). The VSRM treats mass transfer between the gas phase and the different droplet populations and executes bulk or two-section size-resolved chemistry calculations in each step on the basis of the chemical environment of each computational cell. A fall air pollution episode in California's South Coast Air Basin is simulated, and model predictions are compared to observations. In an environment where clouds or fogs are present, the model without aqueous-phase chemistry severely underpredicts secondary sulfate formation. In cases where there is a high potential for sulfate production and widely varying composition across the droplet spectrum (over the ocean and near the coast), there is a significant increase in sulfate production over bulk predictions with the activation of a size-resolved aqueous-phase chemistry module. Unfortunately, measurements were only available at inland sites, where the difference between bulk and size-resolved sulfate predictions was small. The effects of other uncertainties on

  1. Finite size and Coulomb corrections: from nuclei to nuclear liquid vapor phase diagram

    Energy Technology Data Exchange (ETDEWEB)

    Moretto, L.G.; Elliott, J.B.; Phair, L. [Lawrence Berkeley National Laboratory, Nuclear Science Division (United States)

    2003-07-01

    In this paper we consider the problem of obtaining the infinite symmetric uncharged nuclear matter phase diagram from a thermal nuclear reaction. In the first part we shall consider the Coulomb interaction which, because of its long range makes the definition of phases problematic. This Coulomb effect seems truly devastating since it does not allow one to define nuclear phase transitions much above A {approx} 30. However there may be a solution to this difficulty. If we consider the emission of particles with a sizable charge, we notice that a large Coulomb barrier Bc is present. For T << Bc these channels may be considered effectively closed. Consequently the unbound channels may not play a role on a suitably short time scale. Then a phase transition may still be definable in an approximate way. In the second part of the article we shall deal with the finite size problem by means of a new method, the complement method, which shall permit a straightforward extrapolation to the infinite system. The complement approach consists of evaluating the change in free energy occurring when a particle or cluster is moved from one (finite) phase to another. In the case of a liquid drop in equilibrium with its vapor, this is done by extracting a vapor particle of any given size from the drop and evaluating the energy and entropy changes associated with both the vapor particle and the residual liquid drop (complement)

  2. Thermodynamic theory of intrinsic finite-size effects in PbTiO3 nanocrystals. I. Nanoparticle size-dependent tetragonal phase stability

    Science.gov (United States)

    Akdogan, E. K.; Safari, A.

    2007-03-01

    We propose a phenomenological intrinsic finite-size effect model for single domain, mechanically free, and surface charge compensated ΔG-P ⃗s-ξ space, which describes the decrease in tetragonal phase stability with decreasing ξ rigorously.

  3. Studies on two-phase ionic liquid-aqueous flows in small channels of various sizes

    Science.gov (United States)

    Tsaoulidis, Dimitrios; Chinaud, Maxime; Li, Qi; Angeli, Panagiota; University College London Team

    2014-11-01

    Two-phase flows in intensified small-scale systems find increasing applications in (bio)chemical analysis and synthesis, fuel cells, polymerisation, and separation processes (solvent extraction). Ionic liquids are emerging as a useful chemical in different areas of interest because of their unique properties such as negligible volatility and flammability, and good thermal and radiation stability. In this work, the hydrodynamic characteristics during plug flow have been investigated in detail. Experiments were carried out in Teflon channels of different sizes, i.e. 0.5, 1, and 2 mm internal diameter using two-phase systems relevant to spent nuclear fuel reprocessing, i.e. TBP/ionic liquid (30%, v/v)-nitric acid solutions. Important mixing characteristics and circulation patterns within the aqueous plugs have been studied by means of Particle Image Velocimetry (PIV). Finally, the mechanism of plug flow formation and the resulting plug size were investigated using Computational Fluid Dynamic (CFD).

  4. Enhanced defect detection and sizing accuracy using matrix phased array ultrasonic tools

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Roger; Porter, Nancy; Todorov, Evgueni [Edison Welding Institute (EWI), Columbus, OH (United States); Lozev, Mark [BP, Naperville, IL (United States); Reverdy, Frederic [Centre d' Etudes Nucleaires de Saclay (NDT/CEA) Saclay (France). Nondestructive Testing; Benoist, Philippe [Centre d' Etudes Nucleaires de Saclay (NDE/CEA) Saclay (France); Dumas, Philippe [Imasonic, Besancon (France)

    2009-07-01

    Although ultrasonic testing inspection technology and tools have improved significantly, there is still a need for more reliable detection, monitoring, and accurate sizing of crack-like and planar defects, complex corrosion damage, and detection of secondary features within deformed pipe. Ultrasonic two dimensional (2D) matrix phased array technology offers some unique advantages that make the technology promising for improving detection and sizing of pipeline flaws resulting from welding or from in-service damage. Ultrasonic modeling and simulation has been conducted to evaluate the detection and sizing capabilities of 2D matrix arrays for various pipeline inspection concepts. Simulations have been performed using both flexible and rigid array probes. Inspection concepts using rigid probes were evaluated for inspections from both the outside and inside pipe surfaces, while flexible probes were evaluated primarily for inspection from the outside surface when dents or corrosion damage may limit the use of rigid probes. (author)

  5. Surface tension of different sized single-component droplets, according to macroscopic data obtained using the lattice gas model and the critical droplet size during phase formation

    Science.gov (United States)

    Tovbin, Yu. K.; Zaitseva, E. S.; Rabinovich, A. B.

    2017-10-01

    Size dependences of the surface tension of spherical single-component droplets are calculated using equations of the lattice gas model for 19 compounds. Parameters of the model are found from experimental data on the surface tension of these compounds for a macroscopic planar surface. The chosen low-molecular compounds satisfy the law of corresponding states. To improve agreement with the experimental data, Lennard-Jones potential parameters are varied within 10% deviations. The surface tensions of different sized equilibrium droplets are calculated at elevated and lowered temperatures. It is found that the surface tension of droplets grows monotonically as the droplet size increases from zero to its bulk value. The droplet size R 0 corresponding to zero surface tension corresponds to the critical size of the emergence of a new phase. The critical droplet sizes in the new phase of the considered compounds are estimated for the first time.

  6. Initial Droplet Size Impacts pH-Induced Structural Changes in Phase-Separated Polymer Dispersions.

    Science.gov (United States)

    Thongkaew, Chutima; Zeeb, Benjamin; Gibis, Monika; Hinrichs, Jörg; Weiss, Jochen

    2016-05-01

    The effect of pH change on the morphology of whey protein isolate (WPI)-pectin dispersions obtained from phase-separated systems after mild shear was studied. The purpose of this study was to examine the impact of mixing speed on the initial particle size of biopolymer complexes and their structure morphology after sequentially changing the pH. Therefore, solutions of WPI and pectin were combined at pH 6.1, allowed to phase separate and were then mildly homogenized at 50, 100, and 150 rpm, respectively, to form a dispersion containing differently sized WPI droplets in a surrounding pectin-rich phase. Each dispersion was then subjected to a pH change, such as 6.1 to 5.2 and 3.2, by slowly adding hydrochloric acid. The systems morphology, size, appearance, rheology, and storage stability was then characterized by optical microscopy, static light scattering, visual inspections, and steady shear rheometry to gain insights into the structural rearrangements. Results indicated substantial changes in the structure of the dispersion when the pH was changed. Formation of core-shell structures from the WPI droplets was observed at an intermediate pH. There, initial droplet size was found to affect structures formed, that is, core-shell type particles would only form if droplets were large (>1.5 μm) prior to pH change. Insights gained may be of importance to food manufacturers intending to create new structures from mixtures of proteins and carbohydrates. © 2016 Institute of Food Technologists®

  7. Phase Behavior and Domain Size in Sphingomyelin-Containing Lipid Bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Petruzielo, Robin S [Cornell University; Heberle, Frederick A [ORNL; Drazba, Paul [ORNL; Katsaras, John [ORNL; Feigenson, Gerald [Cornell University

    2013-01-01

    Membrane raft size measurements are crucial to understanding the stability and functionality of rafts in cells. The challenge of accurately measuring raft size is evidenced by the disparate reports of domain sizes, which range from nanometers to microns for the ternary model membrane system sphingomyelin (SM)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/cholesterol (Chol). Using F rster resonance energy transfer (FRET) and differential scanning calorimetry (DSC), we established phase diagrams for porcine brain SM (bSM)/dioleoyl-sn-glycero-3-phosphocholine (DOPC)/Chol and bSM/POPC/Chol at 15 and 25 C. By combining two techniqueswith different spatial sensitivities, namely FRET and small-angle neutron scattering (SANS),we have significantly narrowed the uncertainty in domain size estimates for bSM/POPC/Chol mixtures. Compositional trends in FRET data revealed coexisting domains at 15 and 25 C for bothmixtures, while SANS measurements detected no domain formation for bSM/POPC/Chol. Together these results indicate that liquid domains in bSM/POPC/Chol are between 2 and 7 nmin radius at 25 C: that is, domains must be on the order of the 2 6 nmF rster distance of the FRET probes, but smaller than the ~7 nm minimum cluster size detectable with SANS. However, for palmitoyl SM (PSM)/POPC/Chol at a similar composition, SANS detected coexisting liquid domains. This increase in domain size upon replacing the natural SMcomponent (which consists of amixture of chain lengths) with synthetic PSM, suggests a role for SM chain length in modulating raft size in vivo.

  8. Phase behavior and domain size in sphingomyelin-containing lipid bilayers.

    Science.gov (United States)

    Petruzielo, Robin S; Heberle, Frederick A; Drazba, Paul; Katsaras, John; Feigenson, Gerald W

    2013-04-01

    Membrane raft size measurements are crucial to understanding the stability and functionality of rafts in cells. The challenge of accurately measuring raft size is evidenced by the disparate reports of domain sizes, which range from nanometers to microns for the ternary model membrane system sphingomyelin (SM)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/cholesterol (Chol). Using Förster resonance energy transfer (FRET) and differential scanning calorimetry (DSC), we established phase diagrams for porcine brain SM (bSM)/dioleoyl-sn-glycero-3-phosphocholine (DOPC)/Chol and bSM/POPC/Chol at 15 and 25°C. By combining two techniques with different spatial sensitivities, namely FRET and small-angle neutron scattering (SANS), we have significantly narrowed the uncertainty in domain size estimates for bSM/POPC/Chol mixtures. Compositional trends in FRET data revealed coexisting domains at 15 and 25°C for both mixtures, while SANS measurements detected no domain formation for bSM/POPC/Chol. Together these results indicate that liquid domains in bSM/POPC/Chol are between 2 and 7nm in radius at 25°C: that is, domains must be on the order of the 2-6nm Förster distance of the FRET probes, but smaller than the ~7nm minimum cluster size detectable with SANS. However, for palmitoyl SM (PSM)/POPC/Chol at a similar composition, SANS detected coexisting liquid domains. This increase in domain size upon replacing the natural SM component (which consists of a mixture of chain lengths) with synthetic PSM, suggests a role for SM chain length in modulating raft size in vivo. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Micron-Sized Pored Membranes Based on Polyvinylidene Difluoride Hexafluoropropylene Prepared by Phase Inversion Techniques

    Directory of Open Access Journals (Sweden)

    Andreas Hofmann

    2017-10-01

    Full Text Available In this study, micron-sized pored membranes, based on the co-polymer polyvinylidene difluoride hexafluoropropylene (PVdF-HFP were prepared via phase inversion techniques. The aim of the approach was to find less harmful and less toxic solvents to fabricate such films. Therefore, the Hansen solubility approach was used to identify safer and less toxic organic solvents for the phase inversion process, relative to present solvent mixtures, based on acetone, dimethyl formamide, dimethyl acetamide or methanol. With this approach, it was possible to identify cyclopentanone, ethylene glycol and benzyl alcohol as suitable solvents for the membrane preparation process. Physicochemical and mechanical properties were analyzed and compared, which revealed a uniform membrane structure through the cross section. Differences were observed at the top surface, in dependence of both preparation approaches, which are described in detail.

  10. Finite-size effects in Luther-Emery phases of Holstein and Hubbard models

    Science.gov (United States)

    Greitemann, J.; Hesselmann, S.; Wessel, S.; Assaad, F. F.; Hohenadler, M.

    2015-12-01

    The one-dimensional Holstein model and its generalizations have been studied extensively to understand the effects of electron-phonon interaction. The half-filled case is of particular interest, as it describes a transition from a metallic phase with a spin gap due to attractive backscattering to a Peierls insulator with charge-density-wave order. Our quantum Monte Carlo results support the existence of a metallic phase with dominant power-law charge correlations, as described by the Luther-Emery fixed point. We demonstrate that for Holstein and also for purely fermionic models the spin gap significantly complicates finite-size numerical studies, and explains inconsistent previous results for Luttinger parameters and phase boundaries. On the other hand, no such complications arise in spinless models. The correct low-energy theory of the spinful Holstein model is argued to be that of singlet bipolarons with a repulsive, mutual interaction. This picture naturally explains the existence of a metallic phase, but also implies that gapless Luttinger liquid theory is not applicable.

  11. Pressing Induced Polymorphic Phase Transition in Submicron-Sized Gamma-Hmx

    Science.gov (United States)

    Lee, K.-Y.; Moore, D. S.

    2007-12-01

    Using Raman spectroscopy, a novel submicron-sized HMX (sm-HMX) was determined to be both the gamma polymorph and stable with respect to conversion to beta-HMX under ambient conditions for at least a year. Pressing of sm-HMX powder in a small diameter pellet press at pressures from 10,000 psi to 31,000 psi and 1 to 5 minute hold times was found to promote the gamma to beta polymorphic phase transition. The fraction converted and rate of conversion versus time after pellet removal from the press, measured using Raman spectroscopy, fit a sigmoidal curve, indicating nucleation and growth as a possible polymorphic transition mechanism.

  12. Size exclusion chromatography of synthetic polymers and biopolymers on common reversed phase and hydrophilic interaction chromatography columns.

    Science.gov (United States)

    Caltabiano, Anna M; Foley, Joe P; Barth, Howard G

    2016-03-11

    This work describes the applicability of common reversed phase and HILIC columns for size exclusion chromatography of synthetic and natural polymers. Depending on the nature of the solute and column stationary phase, a "non-retention" condition must be created with the aid of the mobile phase to achieve a unique size-based separation in isocratic mode. The various bonded phases show remarkable differences in size separations that are controlled by mobile phase conditions. Polymer-mobile phase and column-mobile phase solvation interactions determine polymer hydrodynamic volume (or solute bulkiness) and polymer-column steric interaction. Solvation interactions in turn depend on polymer, mobile phase and stationary phase polarities. Column-mobile phase solvation interactions determine the structural order of the bonded ligands that can vary from ordered (extended, aligned away from the silica substrate) to disordered (folded, pointing toward the silica substrate). Chain order increases with increased solvent penetration into the bonded phase. Increased chain order reduces pore volume, and therefore decreases the size-separation efficiency of a column. Conversely, decreased chain order increases pore volume and therefore increases the size-separation efficiency. The thermodynamic quality of the mobile phase also plays a significant role in the separation of polymers. "Poor" solvents can significantly reduce the hydrodynamic diameter of a solute and thus change their retention behavior. Medium polarity stationary phases, such as fluoro-phenyl and cyano, exhibit a unique retention behavior. With an appropriate polarity mobile phase, polar and non-polar synthetic polymers of the same molecular masses can be eluted at the same retention volumes. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Size dependence of the phase composition of silver nanoparticles formed by the electric explosion of a wire

    Science.gov (United States)

    Murzakaev, A. M.

    2017-05-01

    Transmission electron microscopy, selected-area electron diffraction, and high-resolution transmission electron microscopy (HRTEM) have been used to determine the morphological and phase features of silver nanoparticles synthesized by a physical method of electric explosion of silver wires. In the nanoparticles obtained, the presence of a hexagonal phase was detected besides the cubic phase and the size dependence of the phase composition of the nanoparticles has been revealed; all particles smaller than 25 nm only had a hexagonal structure, particles with sizes of 25-30 nm contained both the hexagonal and cubic phases, and particles larger than 30 nm had only a cubic structure. Based on an analysis of the conditions of synthesis of silver nanoparticles, an attempt to explain the mechanism of the stabilization of the hexagonal phase depending on the particle size was undertaken.

  14. Hydrophobic silver nanoparticles trapped in lipid bilayers: Size distribution, bilayer phase behavior, and optical properties

    Directory of Open Access Journals (Sweden)

    Bothun Geoffrey D

    2008-11-01

    Full Text Available Abstract Background Lipid-based dispersion of nanoparticles provides a biologically inspired route to designing therapeutic agents and a means of reducing nanoparticle toxicity. Little is currently known on how the presence of nanoparticles influences lipid vesicle stability and bilayer phase behavior. In this work, the formation of aqueous lipid/nanoparticle assemblies (LNAs consisting of hydrophobic silver-decanethiol particles (5.7 ± 1.8 nm embedded within 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC bilayers is demonstrated as a function of the DPPC/Ag nanoparticle (AgNP ratio. The effect of nanoparticle loading on the size distribution, bilayer phase behavior, and bilayer fluidity is determined. Concomitantly, the effect of bilayer incorporation on the optical properties of the AgNPs is also examined. Results The dispersions were stable at 50°C where the bilayers existed in a liquid crystalline state, but phase separated at 25°C where the bilayers were in a gel state, consistent with vesicle aggregation below the lipid melting temperature. Formation of bilayer-embedded nanoparticles was confirmed by differential scanning calorimetry and fluorescence anisotropy, where increasing nanoparticle concentration suppressed the lipid pretransition temperature, reduced the melting temperature, and disrupted gel phase bilayers. The characteristic surface plasmon resonance (SPR wavelength of the embedded nanoparticles was independent of the bilayer phase; however, the SPR absorbance was dependent on vesicle aggregation. Conclusion These results suggest that lipid bilayers can distort to accommodate large hydrophobic nanoparticles, relative to the thickness of the bilayer, and may provide insight into nanoparticle/biomembrane interactions and the design of multifunctional liposomal carriers.

  15. A droplet size dependent multiphase mixture model for two phase flow in PEMFCs

    Energy Technology Data Exchange (ETDEWEB)

    He, Guangli; Yamazaki, Yohtaro [Department of Innovative and Engineered Materials, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo (Japan); Abudula, Abuliti [New Energy Technology Research Division, Aomori Industrial Research Center, Aomori (Japan)

    2009-10-20

    A droplet size dependent multiphase mixture model is developed in this paper, and the droplet size in the gas channel can be considered as a parameter in this multiphase mixture model, which includes the effect of gas diffusion layer (GDL) properties and the gas drag function and cannot be considered in the commonly used multiphase mixture model in the references. The three-dimensional two phase and non-isothermal simulation of the PEMFCs with a straight flow field is performed. The effect of droplet size on the liquid remove, the effect of liquid water on the heat transfer and the effect of gas flow pattern on the heat and mass transfer are mainly investigated. The simulation results show that the large droplet is hard to be dragged by the gas, so it produces large water saturation. The results of the heat transfer show that the liquid water hinders the heat transfer in the GDL and catalyst layer, so it produces the large relative high temperature area, and there are large temperature difference and water saturation in the PEMFCs operated with coflow pattern compared with counter flow pattern. (author)

  16. Micelle size modulation and phase behavior in MEGA-10/Triton X-100 mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Naous, M., E-mail: elzahraadz@yahoo.fr; Molina-Bolívar, J.A.; Ruiz, C. Carnero, E-mail: ccarnero@uma.es

    2014-12-20

    Highlights: • The size of micelles was studied as a function of the micellar composition, NaCl addition and temperature. • Cloud point can be modulated by changing both micellar composition and NaCl addition. • The energetic quantities at the cloud point were evaluated and discussed. - Abstract: This paper reports the effect of temperature and NaCl addition on micelle size and phase behavior in mixtures of N-decanoyl-N-methylglucamide (MEGA-10) and p-tert-octyl-phenoxy polyethylene (9.5) ether (Triton X-100 or TX100). The size of mixed micelles, as determined by dynamic light scattering (DLS), was found to increase with temperature but to be less pronounced at higher proportions of MEGA-10 in the solution. The cloud point was found to increase with an initial increase in the percentage of sugar-based surfactant in the mixture. This phase separation was sensitive to the presence of NaCl in the micellar solution, which induced a cloud point depression, thereby suggesting that the presence of electrolyte produces a marked alteration of the hydration layer of micelles. A thermodynamic analysis was performed assuming the clouding phenomenon to be a liquid–liquid phase-separation process. The resulting ΔG{sub CP}{sup 0} values were positive for all solutions. The cloud point process was exothermic in nature for the mixed micellar system, as proven by the negative value of ΔH{sub CP}{sup 0}. The process was more exothermic as the proportion of sugar-based surfactant in the mixed micelle increased (with and without NaCl in the solution). Furthermore, the negative values of ΔS{sub CP}{sup 0} indicate that the association of micelles in the clouding phenomenon is entropically unfavorable. It was observed from the enthalpy–temperature plots that the change in heat capacity is negative, thus indicating the important role played by dehydration in this thermodynamic process. This study found that the enthalpy–entropy compensation relationship holds for this

  17. Broadband beam shaping using two cascaded diffractive optical elements with different sizes of effective phase region

    Science.gov (United States)

    Ding, Li; Cao, Guowei; Guo, Jin; Wang, Jun; Huang, Kun; Li, Yongping; Kang, Xueliang; Wang, Liang

    2017-10-01

    A unique design method of two cascaded diffractive optical elements (DOEs) with different sizes of effective phase region to modulate broadband beam is presented with consideration of single production material and low relief height on DOE. The iterative algorithm to calculate the relief heights on these DOEs is introduced at first. Where after, a broadband beam at wavelength from 500nm to 600nm propagates through the designed DOEs and is focused on the target plane in the simulation part. The shaping results demonstrate the excellent shaping ability of this unique design method. The shaping system proposed in this paper is significant for nonmonochromatic light modulation and has many applications such as graphic encryption, three-dimensional color display and multi wavelength division multiplexing.

  18. Particle Size and Crystal Phase Effects in Fischer-Tropsch Catalysts

    Directory of Open Access Journals (Sweden)

    Jin-Xun Liu

    2017-08-01

    Full Text Available Fischer-Tropsch synthesis (FTS is an increasingly important approach for producing liquid fuels and chemicals via syngas—that is, synthesis gas, a mixture of carbon monoxide and hydrogen—generated from coal, natural gas, or biomass. In FTS, dispersed transition metal nanoparticles are used to catalyze the reactions underlying the formation of carbon-carbon bonds. Catalytic activity and selectivity are strongly correlated with the electronic and geometric structure of the nanoparticles, which depend on the particle size, morphology, and crystallographic phase of the nanoparticles. In this article, we review recent works dealing with the aspects of bulk and surface sensitivity of the FTS reaction. Understanding the different catalytic behavior in more detail as a function of these parameters may guide the design of more active, selective, and stable FTS catalysts.

  19. Calibrations of phase abundance, composition, and particle size distribution for olivine-orthopyroxene mixtures from reflectance spectra

    Science.gov (United States)

    Cloutis, Edward A.; Gaffey, Michael J.; Jackowski, Timothy L.; Reed, Kevin L.

    1986-01-01

    An analytical method for quantifying the characteristics (phase abundances, phase composition, and grain size) of an olivine-orthopyroxene mixture from reflectance spectra is described. The spectral parameters related to reflectance, wavelength position, and albedo are investigated; the absorption bands for the olivine-orthopyroxene mixture is also studied. Primary calibrations useful for the determination of the olivine-orthopyroxene mixture characteristics are examined.

  20. Multidimensional profiling of plasma lipoproteins by size exclusion chromatography followed by reverse-phase protein arrays

    Science.gov (United States)

    Dernick, Gregor; Obermüller, Stefan; Mangold, Cyrill; Magg, Christine; Matile, Hugues; Gutmann, Oliver; von der Mark, Elisabeth; Handschin, Corinne; Maugeais, Cyrille; Niesor, Eric J.

    2011-01-01

    The composition of lipoproteins and the association of proteins with various particles are of much interest in the context of cardiovascular disease. Here, we describe a technique for the multidimensional analysis of lipoproteins and their associated apolipoproteins. Plasma is separated by size exclusion chromatography (SEC), and fractions are analyzed by reverse-phase arrays. SEC fractions are spotted on nitrocellulose slides and incubated with different antibodies against individual apolipoproteins or antibodies against various apolipoproteins. In this way, tens of analytes can be measured simultaneously in 100 μl of plasma from a single SEC separation. This methodology is particularly suited to simultaneous analysis of multiple proteins that may change their distribution to lipoproteins or alter their conformation, depending on factors that influence circulating lipoprotein size or composition. We observed changes in the distribution of exchangeable apolipoproteins following addition of recombinant apolipoproteins or interaction with exogenous compounds. While the cholesteryl ester transfer protein (CETP)-dependent formation of pre-β-HDL was inhibited by the CETP inhibitors torcetrapib and anacetrapib, it was not reduced by the CETP modulator dalcetrapib. This finding was elucidated using this technique. PMID:21971713

  1. Geochemical phase and particle size relationships of metals in urban road dust.

    Science.gov (United States)

    Jayarathne, Ayomi; Egodawatta, Prasanna; Ayoko, Godwin A; Goonetilleke, Ashantha

    2017-11-01

    Detailed knowledge of the processes that metals undergo during dry weather periods whilst deposited on urban surfaces and their environmental significance is essential to predict the potential influence of metals on stormwater quality in order to develop appropriate stormwater pollution mitigation measures. However, very limited research has been undertaken in this area. Accordingly, this study investigated the geochemical phase and particle size relationships of seven metals which are commonly associated with urban road dust, using sequential extraction in order to assess their mobility characteristics. Metals in the sequentially extracted fractions of exchangeable, reducible, oxidisable and residual were found to follow a similar trend for different land uses even though they had variable accumulation loads. The high affinity of Cd and Zn for exchangeable reactions in both, bulk and size-fractionated solid samples confirmed their high mobility, while the significant enrichment of Ni and Cr in the stable residual fraction indicated a low risk of mobility. The study results also confirmed the availability of Cu, Pb and Mn in both, stable and mobile fractions. The fine fraction of solids (<150 μm) and antecedent dry days can be highlighted as important parameters when determining the fate of metals associated with urban road dust. The outcomes from this study are expected to contribute to the development of effective stormwater pollution mitigation strategies by taking into consideration the metal-particulate relationships. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Finite-size, chemical-potential and magnetic effects on the phase transition in a four-fermion interacting model

    Energy Technology Data Exchange (ETDEWEB)

    Correa, E.B.S. [Universidade Federal do Sul e Sudeste do Para, Instituto de Ciencias Exatas, Maraba (Brazil); Centro Brasileiro de Pesquisas Fisicas-CBPF/MCTI, Rio de Janeiro (Brazil); Linhares, C.A. [Universidade do Estado do Rio de Janeiro, Instituto de Fisica, Rio de Janeiro (Brazil); Malbouisson, A.P.C. [Centro Brasileiro de Pesquisas Fisicas-CBPF/MCTI, Rio de Janeiro (Brazil); Malbouisson, J.M.C. [Universidade Federal da Bahia, Instituto de Fisica, Salvador (Brazil); Santana, A.E. [Universidade de Brasilia, Instituto de Fisica, Brasilia, DF (Brazil)

    2017-04-15

    We study effects coming from finite size, chemical potential and from a magnetic background on a massive version of a four-fermion interacting model. This is performed in four dimensions as an application of recent developments for dealing with field theories defined on toroidal spaces. We study effects of the magnetic field and chemical potential on the size-dependent phase structure of the model, in particular, how the applied magnetic field affects the size-dependent critical temperature. A connection with some aspects of the hadronic phase transition is established. (orig.)

  3. Size Dependence of a Temperature-Induced Solid-Solid Phase Transition in Copper(I) Sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Rivest, Jessy B; Fong, Lam-Kiu; Jain, Prashant K; Toney, Michael F; Alivisatos, A Paul

    2011-07-24

    Determination of the phase diagrams for the nanocrystalline forms of materials is crucial for our understanding of nanostructures and the design of functional materials using nanoscale building blocks. The ability to study such transformations in nanomaterials with controlled shape offers further insight into transition mechanisms and the influence of particular facets. Here we present an investigation of the size-dependent, temperature-induced solid-solid phase transition in copper sulfide nanorods from low- to high-chalcocite. We find the transition temperature to be substantially reduced, with the high chalcocite phase appearing in the smallest nanocrystals at temperatures so low that they are typical of photovoltaic operation. Size dependence in phase trans- formations suggests the possibility of accessing morphologies that are not found in bulk solids at ambient conditions. These other- wise-inaccessible crystal phases could enable higher-performing materials in a range of applications, including sensing, switching, lighting, and photovoltaics.

  4. Domain Size of Phase-Separated NaxCoO2 as Investigated by X-Ray Microdiffraction

    Directory of Open Access Journals (Sweden)

    Hideharu Niwa

    2017-03-01

    Full Text Available O3-NaCoO 2 is a promising cathode material for sodium ion secondary batteries (SIBs. Na x CoO 2 shows phase separation (PS into the O3 and O ′ 3 phases in the Na concentration range of 0.89 ⩽ x ⩽ 0.99. In order to estimate the domain size (r in the two-phase region, we performed X-ray microdiffraction (XRMD of thin films of Na x CoO 2 at x = 0.97 and ∼1. We found that r (≈400 nm of the O ′ 3 domain is comparable to the particle size d (=331 ± 87 nm in the as-grown O3-NaCoO 2 film. This observation suggests that individual particles of Na x CoO 2 are single phase to minimize the strain at the O3–O ′ 3 phase boundary.

  5. Organic solvent modifier and temperature effects in non-aqueous size-exclusion chromatography on reversed-phase columns.

    Science.gov (United States)

    Caltabiano, Anna M; Foley, Joe P; Striegel, André M

    2018-01-05

    Common reversed-phase columns (C18, C4, phenyl, and cyano) offer inert surfaces suitable for the analysis of polymers by size-exclusion chromatography (SEC). The effect of tetrahydrofuran (THF) solvent and the mixtures of THF with a variety of common solvents used in high performance liquid chromatography (acetonitrile, methanol, dimethylformamide, 2-propanol, ethanol, acetone and chloroform) on reversed-phase stationary phase characteristics relevant to size exclusion were studied. The effect of solvent on the elution of polystyrene (PS) and poly(methyl methacrylate) (PMMA) and the effect of column temperature (within a relatively narrow range corresponding to typical chromatographic conditions, i.e., 10°C-60°C) on the SEC partition coefficients KSEC of PS and PMMA polymers, were also investigated. The bonded phases show remarkable differences in size separations when binary mixtures of THF with other solvents are used as the mobile phase. The solvent impact can be two-fold: (i) change of the polymeric coil size, and possible shape, and (ii) change of the stationary phase pore volume. If the effect of this impact is properly moderated, then the greatest benefit of optimized solute resolution can be achieved. Additionally, this work provides an insight on solvent-stationary phase interactions and their effects on column pore volume. The only effect of temperature observed in our studies was a decreased elution volume of the polymers with increasing temperature. SEC partition coefficients were temperature-independent in the range of 10°C-60°C and therefore, over this temperature range elution of PS and PMMA polymers is by near-ideal SEC on reversed-phase columns. Non-ideal SEC appears to occur for high molar mass PMMA polymers on a cyano column when alcohols are used as mobile phase modifiers. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. A multi-phase algorithm for a joint lot-sizing and pricing problem with stochastic demands

    DEFF Research Database (Denmark)

    Jenny Li, Hongyan; Thorstenson, Anders

    2014-01-01

    Stochastic lot-sizing problems have been addressed quite extensively, but relatively few studies also consider marketing factors, such as pricing. In this paper, we address a joint stochastic lot-sizing and pricing problem with capacity constraints and backlogging for a firm that produces a single...... to a practically viable approach to decision-making. In addition to incorporating market uncertainty and pricing decisions in the traditional production and inventory planning process, our approach also accommodates the complexity of time-varying cost and capacity constraints. Finally, our numerical results show...... prices and lot sizes simultaneously. Therefore, we decompose the joint lot-sizing and pricing problem with stochastic demands and capacity constraints into a multi-phase decision process. In each phase, we solve the associated sub-problem to optimality. The decomposed decision process corresponds...

  7. Evolution of grain sizes and orientations during phase transitions in hydrous Mg2SiO4

    Science.gov (United States)

    Rosa, Angelika D.; Hilairet, Nadège; Ghosh, Sujoy; Perrillat, Jean-Philippe; Garbarino, Gaston; Merkel, Sébastien

    2016-10-01

    Transformation microstructures in mantle minerals, such as (Mg,Fe)2SiO4, are critical for predicting the rheological properties of rocks and the interpretation of seismic observations. We present in situ multigrain X-ray diffraction experiments on hydrous Mg2SiO4 at the P/T conditions relevant for deep cold subducting slabs (up to 40 GPa and 850°C) at a low experimental strain rate ( 4 * 10-6s-1). We monitor the orientations of hundreds of grains and grain size variations during the series of α-β-γ (forsterite-wadsleyite-ringwoodite) phase transformations. Microtextural results indicate that the β and an intermediate γ* phase grow incoherently relatively to the host α phase consistent with a nucleation and growth model. The β and γ phases exhibit orientation relationships which are in agreement with previous ex situ observations. The β and intermediate γ* show texturing due to moderate differential stress in the sample. Both the α-β and α-γ transformation induce significant reductions of the mean sample grain size of up to 90% that starts prior to the appearance of the daughter phase. Apart from the γ*, in the newly formed β and γ phases, the nucleation rate is faster than the growth rate, inhibiting the formation of large grains. These results on grain orientations and grain size reductions in relation to transformation kinetics should allow refining existing slab strength models.

  8. Difference of contrast enhancement characteristics of hepatic hemangiomas according to lesion size on two-phase spiral CT

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Sung Hye; Yoon, Suk Kwon; Yang, Dal Mo; Yoon, Myung Hwan; Kim, Hak Soo; Kim, Hyung Sik; Chung, Jin Woo [Chungang Gil Hospital, Incheon (Korea, Republic of)

    1998-06-01

    The purpose of this study is to determine the different of enhancement patterns of hepatic hemangioma according to the lesion size, using dual-phase spiral CT. Fifty-nine lesions in 45 patients with hepatic hemangiomas were subjected to spiral CT. According to size, the lesions were divided into two groups (<2.5 cm : n=34;> {>=} 2.5 cm : n=25). The enhancement patterns of the lesions were classified as one of four types (homogeneous hyperdense, peripheral hyperdense, central hyperdense, peripheral hyperdense, central hyperdense, or hypodense) during the early phase, and as one of five types (homogeneous hyperdense, peripheral hyperdense, central hyperdense, hypodense of isodense) during the delayed phase. We evaluated differences in enhancement patterns during the early and delayed phase according to lesion size. During the early phase, the enhancement patterns of lesions large than 2.5 cm were peripheral hyperdense (96%) or homogeneous hyperdense (4%); those of less than 2.5 cm were peripheral hyperdense (53%), homogenous hyperdense (26%), hypodense (18%), or central hyperdense (3%). Thus, hemangiomas in these two groups usually showed a peripheral enhancement patterns were more common. During the delayed phase, the enhancement patterns of lesions larger than 2.5 cm were peripheral hyperdense (3%), or isodense (3%). Thus, the enhancement patterns of lesions larger than 2.5 cm showed a homogeneous enhancement pattern. The enhancement patterns of hepatic hemangiomas differ according to lesion size. A knowledge of these differences is helpful in the diagnosis of hepatic hemangioma. (author). 16 refs., 2 tabs., 3 figs.

  9. Pronounced Size Dependence in Structure and Morphology of Gas-Phase Produced, Partially Oxidized Cobalt Nanoparticles under Catalytic Reaction Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bartling, Stephan; Yin, Chunrong; Barke, Ingo; Oldenburg, Kevin; Hartmann, Hannes; von Oeynhausen, Viola; Pohl, Marga-Martina; Houben, Kelly; Tyo, Eric C.; Seifert, Sönke; Lievens, Peter; Meiwes-Broer, Karl-Heinz; Vajda, Stefan

    2015-06-23

    It is generally accepted that optimal particle sizes are key for efficient nanocatalysis. Much less attention is paid to the role of morphology and atomic arrangement during catalytic reactions. Here we unravel the structural, stoichiometric, and morphological evolution of gas-phase produced cobalt nanoparticles in a broad size range. Particles with diameters between 1.4 nm and 22nm generated in cluster sources are size selected and deposited on amorphous alumina (Al2O3) and ultrananocrystalline diamond (UNCD) films. A combination of different techniques is employed to monitor particle properties at the stages of production, exposure to ambient conditions, and catalytic reaction, in this case the oxidative dehydrogenation of cyclohexane at elevated temperatures. A pronounced size dependence is found, naturally classifying the particles into three size regimes. While small and intermediate clusters essentially retain their compact morphology, large particles transform into hollow spheres due to the nanoscale Kirkendall effect. Depending on the substrate an isotropic (Al2O3) or anisotropic (UNCD) Kirkendall effect is observed. The latter results in dramatic lateral size changes. Our results shed light on the interplay between chemical reactions and the catalyst's structure and provide an approach to tailor the cobalt oxide phase composition required for specific catalytic schemes.

  10. Synthesis of nanoparticles in a flame aerosol reactor with independent and strict control of their size, crystal phase and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Jingkun; Chen, D-R; Biswas, Pratim [Aerosol and Air Quality Research Laboratory, Department of Energy, Environmental and Chemical Engineering, Washington University in St Louis, Campus Box 1180, St Louis, MO 63130 (United States)

    2007-07-18

    A flame aerosol reactor (FLAR) was developed to synthesize nanoparticles with desired properties (crystal phase and size) that could be independently controlled. The methodology was demonstrated for TiO{sub 2} nanoparticles, and this is the first time that large sets of samples with the same size but different crystal phases (six different ratios of anatase to rutile in this work) were synthesized. The degree of TiO{sub 2} nanoparticle agglomeration was determined by comparing the primary particle size distribution measured by scanning electron microscopy (SEM) to the mobility-based particle size distribution measured by online scanning mobility particle spectrometry (SMPS). By controlling the flame aerosol reactor conditions, both spherical unagglomerated particles and highly agglomerated particles were produced. To produce monodisperse nanoparticles, a high throughput multi-stage differential mobility analyser (MDMA) was used in series with the flame aerosol reactor. Nearly monodisperse nanoparticles (geometric standard deviation less than 1.05) could be collected in sufficient mass quantities (of the order of 10 mg) in reasonable time (1 h) that could be used in other studies such as determination of functionality or biological effects as a function of size.

  11. Role of Acid–Base Equilibria in the Size, Shape, and Phase Control of Cesium Lead Bromide Nanocrystals

    Science.gov (United States)

    2018-01-01

    A binary ligand system composed of aliphatic carboxylic acids and primary amines of various chain lengths is commonly employed in diverse synthesis methods for CsPbBr3 nanocrystals (NCs). In this work, we have carried out a systematic study examining how the concentration of ligands (oleylamine and oleic acid) and the resulting acidity (or basicity) affects the hot-injection synthesis of CsPbBr3 NCs. We devise a general synthesis scheme for cesium lead bromide NCs which allows control over size, size distribution, shape, and phase (CsPbBr3 or Cs4PbBr6) by combining key insights on the acid–base interactions that rule this ligand system. Furthermore, our findings shed light upon the solubility of PbBr2 in this binary ligand system, and plausible mechanisms are suggested in order to understand the ligand-mediated phase control and structural stability of CsPbBr3 NCs. PMID:29381326

  12. The Orbital and Planetary Phase Variations of Jupiter-sized Planets: Characterizing Present and Future Giants

    Science.gov (United States)

    Mayorga, Laura C.; Jackiewicz, Jason; Rages, Kathy; West, Robert; Knowles, Ben; Lewis, Nikole K.; Marley, Mark S.

    2018-01-01

    Knowledge of how the brightness and color of a planet varies with viewing angle is essential for the design of future direct imaging missions and deriving constraints on atmospheric properties. However, measuring the phase curves for the solar system gas giants is impossible from the ground. Using data Cassini/ISS obtained during its flyby of Jupiter, I measured Jupiter's phase curve in six bands spanning 400-1000 nm. I found that Jupiter's brightness is less than that of a Lambertian scatterer and that its color varies more with phase angle than predicted by theoretical models. For hot Jupiters, the light from the planet cannot be spatially isolated from that of the star. As a result, determining the planetary phase curve requires removing the phase-dependent contributions from the host star. I consider the effect of varying the stellar model and present a parameterization of the Doppler beaming amplitude that depends upon the planetary mass, orbital period, and the stellar temperature. I consider the detectability of Doppler beaming amplitudes with data from TESS and find that TESS will be less sensitive to this signal than Kepler. This work was supported by the National Science Foundation Graduate Research Fellowship Program and the New Mexico Higher Education Department Graduate Scholarship Program.

  13. Experimental investigation of the two-phase flow regimes and pressure drop in horizontal mini-size rectangular test section

    Science.gov (United States)

    Elazhary, Amr Mohamed; Soliman, Hassan M.

    2012-10-01

    An experimental study was conducted in order to investigate two-phase flow regimes and fully developed pressure drop in a mini-size, horizontal rectangular channel. The test section was machined in the form of an impacting tee junction in an acrylic block (in order to facilitate visualization) with a rectangular cross-section of 1.87-mm height on 20-mm width on the inlet and outlet sides. Pressure drop measurement and flow regime identification were performed on all three sides of the junction. Air-water mixtures at 200 kPa (abs) and room temperature were used as the test fluids. Four flow regimes were identified visually: bubbly, plug, churn, and annular over the ranges of gas and liquid superficial velocities of 0.04 ≤ JG ≤ 10 m/s and 0.02 ≤ JL ≤ 0.7 m/s, respectively, and a flow regime map was developed. Accuracy of the pressure-measurement technique was validated with single-phase, laminar and turbulent, fully developed data. Two-phase experiments were conducted for eight different inlet conditions and various mass splits at the junction. Comparisons were conducted between the present data and former correlations for the fully developed two-phase pressure drop in rectangular channels with similar sizes. Wide deviations were found among these correlations, and the correlations that agreed best with the present data were identified.

  14. Synchronization of oscillators with long range interaction: Phase transition and anomalous finite size effects

    DEFF Research Database (Denmark)

    Marodi, M.; D'ovidio, Francesco; Vicsek, T.

    2002-01-01

    of elements. For large number of oscillators and small coupling constant, numerical simulations and analytical arguments indicate that a phase transition separating synchronization from incoherence appears at a decay exponent value equal to the number of dimensions of the lattice. In contrast with earlier......Synchronization in a lattice of a finite population of phase oscillators with algebraically decaying, non-normalized coupling is studied by numerical simulations. A critical level of decay is found, below which full locking takes place if the population contains a sufficiently large number...

  15. Non-Factorizable Phases, Yukawa Textures and the Size of sin$2\\beta$

    CERN Document Server

    Branco, Gustavo Castello; Silva-Marcos, Joaquim I

    2004-01-01

    We emphasize the crucial r\\^ ole played by non-factorizable phases in the analysis of the Yukawa flavour structure performed in weak bases with Hermitian mass matrices and with vanishing $(1,1)$ entries. We show that non-factorizable phases are important in order to generate a sufficiently large $\\sin 2 \\beta $. A method is suggested to reconstruct the flavour structure of Yukawa couplings from input experimental data both in this Hermitian basis and in a non-Hermitian basis with a maximal number of texture zeros. The corresponding Froggatt--Nielsen patterns are presented in both cases.

  16. Photostimulated luminescence from a fluorobromozirconate glass-ceramic and the effect of crystallite size and phase

    CERN Document Server

    Secu, M; Spaeth, J M; Edgar, A; Williams, G V M; Rieser, U

    2003-01-01

    We report a systematic study of the photoluminescence (PL), photostimulated luminescence (PSL) and thermostimulated luminescence (TSL) from europium-and bromine-doped fluorozirconate glass-ceramics. Eu sup 2 sup + ions in the as-prepared glass show no PL, but after suitable thermal annealing hexagonal phase and orthorhombic phase barium bromide crystallites are precipitated and PL is observed from Eu sup 2 sup + ions in these crystallites. Room temperature PSL is observed from the orthorhombic phase, with an efficiency which is up to 9% of the well known crystalline storage phosphor BaFBr:Eu sup 2 sup +. The emission is at 404 nm, and there is a maximum in the stimulation at 580 nm. We associate the PSL with an optically quenchable peak in the glow curve, which has an activation energy of 1.20 eV and attribute this feature to a perturbed F centre. Room temperature PSL from glass-ceramics containing predominantly the hexagonal phase of BaBr sub 2 has a relative efficiency of less than 0.07%. The resultant trap...

  17. Numerical method for estimating the size of chaotic regions of phase space

    Energy Technology Data Exchange (ETDEWEB)

    Henyey, F.S.; Pomphrey, N.

    1987-10-01

    A numerical method for estimating irregular volumes of phase space is derived. The estimate weights the irregular area on a surface of section with the average return time to the section. We illustrate the method by application to the stadium and oval billiard systems and also apply the method to the continuous Henon-Heiles system. 15 refs., 10 figs. (LSP)

  18. Effect of initial nickel particle size on stability of nickel catalysts for aqueous phase reforming

    NARCIS (Netherlands)

    Haasterecht, Van Tomas; Swart, Marten; Jong, De Krijn P.; Bitter, J.H.

    2016-01-01

    The deactivation behavior by crystallite growth of nickel nanoparticles on various supports (carbon nanofibers, zirconia, SiC, α-Al2O3 and γ-Al2O3) was investigated in the aqueous phase reforming of ethylene glycol. Supported Ni catalysts of ∼10 wt% were prepared by impregnation of carbon nanofibers

  19. Effect of initial nickel particle size on stability of nickel catalysts for aqueous phase reforming

    NARCIS (Netherlands)

    Van Haasterecht, Tomas; Swart, Marten; De Jong, Krijn P.; Bitter, Johannes Hendrik

    The deactivation behavior by crystallite growth of nickel nanoparticles on various supports (carbon nanofibers, zirconia, SiC, α-Al2O3 and γ-Al2O3) was investigated in the aqueous phase reforming of ethylene glycol. Supported Ni catalysts of ∼10 wt% were prepared by impregnation of carbon nanofibers

  20. "Does lipoprotein size change with consumption of NCEP phase 2 diet in hypercholesterolemic adolescents? "

    Directory of Open Access Journals (Sweden)

    Azadbakht L

    2007-04-01

    Full Text Available Background: The NCEP step II diet produced a desirable lipoprotein response in hypercholesterolemia. A relation between plasma concentrations of small dense LDL and cardiovascular risk factors has also been mentioned in children. This study was conducted to determine the effects of the National Cholesterol Education Program (NCEP step 2 diets on the low density and high density lipoprotein particle size in dyslipidemic adolescents. Methods: Forty- four dyslipidemic adolescents, aged 10-18 years, participated in this case-control study. The control group was not given a diet prescription and was simply instructed to “eat as usual”. Their eating patterns reflected the consumption of macronutrients, fruit, vegetables and dairy products, typical of what many Tehranian eat. NCEP step 2 diets was a diet with 30% of calories as total fat, less than 7% saturated fat, less than 200 mg cholesterol, less than 15% of calories as monounsaturated fat and less than 10% as polyunsaturated fat per day. Lipoprotein particle size was the major outcome variables, which was measured after 3 months of intervention. Lipoprotein particle size was estimated by nondenaturing polyacrylamide gradient gel electrophoresis using Krauss and Burke methodtion. Results: The mean body mass index was 26.3±4.2 kg/m2. Baseline characteristics of these adolescents did not differ significantly across the NCEP step 2 and control diet groups. The NCEP diet resulted in higher reduction in total cholesterol (-13±4 vs –2±0.3 mg/dl, p<0.001, LDL (-9±2 vs 3±0.6 mg/dl, p<0.01 and higher increase in size of the LDL (1.7±0.4 vs 0.1±0.4 mg/dl, p<0.001. HDL particle size did not change significantly. The prevalence of hypercholesterolemia decreased significantly (p<0.05 in NCEP step 2 group (68% in NCEP step 2 vs 100% in the control group after 3 months. Conclusion: NCEP step 2 diet not only reduces the serum LDL concentration of hypercholesterolemic adolescents but also has a

  1. Optimization of size and shape of composite heat sinks with phase change materials

    Science.gov (United States)

    Balaji, C.; Mungara, Praneet; Sharma, Parw

    2011-05-01

    A composite heat sink is one in which a phase change material is interspersed with a high thermal conductivity base material to maximize the thermal performance of the device. Unlike constant area fins considered in literature, this work considers a repeating elemental composite heat sink (ECHS) with variable area fins. The base material is aluminium and the phase change material is n-Eicosane. An in house code was developed in MATLABto determine the time of operation for a vertical fins ECHS for a one dimensional approximation. This was followed by a two dimensional analysis of the problem using FLUENT 6.3. The effects of the shape of the interface surface on the time of operation and overall heat dissipated are determined and design modifications for the composite Heat Sinks based on the results obtained are suggested.

  2. Ultrasonic Phased Array Technique for Accurate Flaw Sizing in Dissimilar Metal Welds

    Energy Technology Data Exchange (ETDEWEB)

    Jonathan D Buttram

    2005-03-11

    Described is a manual,portable non-destructive technique to determine the through wall height of cracks present in dissimilar metal welds used in the primary coolling systems of pressure water and boiler light water reactors. Current manual methods found in industry have proven not to exhibit the sizing accuracy required by ASME inspection requirement. The technique described demonstrated an accuracy approximately three times that required to ASME Section XI, Appendix 8 qualification.

  3. Phase-coherent electron transport through metallic atomic-sized contacts and organic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Pauly, F.

    2007-02-02

    This work is concerned with the theoretical description of systems at the nanoscale, in particular the electric current through atomic-sized metallic contacts and organic molecules. In the first part, the characteristic peak structure in conductance histograms of different metals is analyzed within a tight-binding model. In the second part, an ab-initio method for quantum transport is developed and applied to single-atom and single-molecule contacts. (orig.)

  4. Effects of secondary phase and grain size on the corrosion of biodegradable Mg-Zn-Ca alloys.

    Science.gov (United States)

    Lu, Y; Bradshaw, A R; Chiu, Y L; Jones, I P

    2015-03-01

    The bio-corrosion behaviour of Mg-3Zn-0.3Ca (wt.%) alloy in simulated body fluid (SBF) at 37°C has been investigated using immersion testing and electrochemical measurements. Heat treatment has been used to alter the grain size and secondary phase volume fraction; the effects of these on the bio-corrosion behaviour of the alloy were then determined. The as-cast sample has the highest bio-corrosion rate due to micro-galvanic corrosion between the eutectic product (Mg+Ca2Mg6Zn3) and the surrounding magnesium matrix. The bio-corrosion resistance of the alloy can be improved by heat treatment. The volume fraction of secondary phases and grain size are both key factors controlling the bio-corrosion rate of the alloy. The bio-corrosion rate increases with volume fraction of secondary phase. When this is lower than 0.8%, the dependence of bio-corrosion rate becomes noticeable: large grains corrode more quickly. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Phase, size and shape controlled formation of aerosol generated nickel and nickel oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, D., E-mail: d.ponce@ucl.ac.uk [Department of Physics and Astronomy, University College London, WC1E 6BT London (United Kingdom); London Centre for Nanotechnology, Gordon Street, WC1H 0AH London (United Kingdom); Kuznetsov, M.V. [N.P. Ogarev Mordovian State University, Saransk, Republic of Mordovia 430005 (Russian Federation); Morozov, Yu.G.; Belousova, O.V. [Institute of Structural Macrokinetics and Materials Science, Chernogolovka, Moscow Region 142432 (Russian Federation); Parkin, I.P. [Department of Chemistry, Materials Chemistry Centre, University College London, 20 Gordon Street, WC1H 0AJ London (United Kingdom)

    2013-12-05

    Highlights: •Structural and magnetic characterization of aerosol Ni nanoparticles. •Experimental parameters affecting size, shape and composition are discussed. •Larger spherical particles with the highest Ni content are produced by using an Ar flow. •Coalescence rate of primary particles is accelerated by increasing Ni feeding rate. •Ni nanoparticles show bulk-like saturation magnetization values. -- Abstract: Ferromagnetic Ni nanoparticles were formed by a levitation-jet aerosol synthesis under different gas environments and metal precursor feed rates. At a constant background gas inlet temperature, it was found that a higher Ni loading resulted in enhanced particle growth through coalescence. He partial atmosphere favors surface condensation of evaporated Ni atoms over coalescence as the surface area reduction mechanism in the nanoparticles. A flow of 2.5% air in the background gas mixture was enough to oxidize 75% of the initial Ni load, inducing a drastic destabilization of particle size and shape distribution. Regardless of the background inert gas composition, necked nanoparticles were observed in samples prepared with a 1 g/h Ni feed rate, whereas discrete nanoparticles resulted from a higher feed rate of ca. 4 g/h, confirming the key role of Ni loading on the rate of coalescence. The highest saturation magnetization (51.75 A m{sup 2} kg{sup −1} measured at 300 K) and the lowest coercivity (0.008 T) were obtained under an Ar flow. Zero-field cooled and field-cooled magnetization curves measured under an applied field of 10{sup −2} T revealed that the blocking processes of nanoparticles are dominated by their particle size distributions, with some features attributable to interparticle interactions.

  6. Ising Superconductivity and Quantum Phase Transition in Macro-Size Monolayer NbSe2

    Science.gov (United States)

    Xing, Ying; Zhao, Kun; Shan, Pujia; Zheng, Feipeng; Zhang, Yangwei; Fu, Hailong; Liu, Yi; Tian, Mingliang; Xi, Chuanying; Liu, Haiwen; Feng, Ji; Lin, Xi; Ji, Shuaihua; Chen, Xi; Xue, Qi-Kun; Wang, Jian

    2017-11-01

    Two-dimensional (2D) transition metal dichalcogenides (TMDs) have a range of unique physics properties and could be used in the development of electronics, photonics, spintronics and quantum computing devices. The mechanical exfoliation technique of micro-size TMD flakes has attracted particular interest due to its simplicity and cost effectiveness. However, for most applications, large area and high quality films are preferred. Furthermore, when the thickness of crystalline films is down to the 2D limit (monolayer), exotic properties can be expected due to the quantum confinement and symmetry breaking. In this paper, we have successfully prepared macro-size atomically flat monolayer NbSe2 films on bilayer graphene terminated surface of 6H-SiC(0001) substrates by molecular beam epitaxy (MBE) method. The films exhibit an onset superconducting critical transition temperature above 6 K, 2 times higher than that of mechanical exfoliated NbSe2 flakes. Simultaneously, the transport measurements at high magnetic fields reveal that the parallel characteristic field Bc// is at least 4.5 times higher than the paramagnetic limiting field, consistent with Zeeman-protected Ising superconductivity mechanism. Besides, by ultralow temperature electrical transport measurements, the monolayer NbSe2 film shows the signature of quantum Griffiths singularity when approaching the zero-temperature quantum critical point.

  7. Determination of pore size distributions in capillary-channeled polymer fiber stationary phases by inverse size-exclusion chromatography and implications for fast protein separations.

    Science.gov (United States)

    Wang, Zhengxin; Marcus, R Kenneth

    2014-07-18

    Capillary-channeled polymer (C-CP) fibers have been utilized as liquid chromatography stationary phases, primarily for biomacromolecule separations on the analytical and preparative scales. The collinear packing of the eight-channeled C-CP fibers provides for very efficient flow, allowing operation at high linear velocity (u>100mm s(-1)) and low backpressure (chromatography (iSEC) has been employed to determine the pore size distribution (PSD) within C-CP fibers. A diversity of test species (from metal ions to large proteins) was used as probes under non-retaining conditions to obtain a response curve reflecting the apparent partition coefficient (Kd) versus hydrodynamic radii (rm). A mean pore radius (rp) of 4.2nm with standard deviation (sp) of ±1.1nm was calculated by fitting the Kd versus rm data to model equations with a Gaussian pore size distribution, and a pore radius of 4.0±0.1nm was calculated based on a log-normal distribution. The derived mean pore radius is much smaller than traditional support materials, with the standard deviation showing a relatively uniform pore distribution. van Deemter plots were analyzed to provide practical confirmation of the structural implications. Large molecules (e.g., proteins) that are fully excluded from pores have no significant C-terms in the van Deemter plots whereas small molecules that can access the pore volumes display appreciable C-terms, as expected. Fitting of retention data to the Knox equation suggests that the columns operate with a characteristic particle diameter (dp) of ∼53μm. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Considerations for RTCA Phase 2 Low Size, Weight, and Power (SWAP) Surveillance Requirements. UAS Integration in the NAS

    Science.gov (United States)

    Santiago, Confesor

    2017-01-01

    RTCA (Radio Technical Commission for Aeronautics) Special Committee 228 has initiated a second phase for the development of minimum operational performance standards (MOPS) for UAS (Unmanned Aircraft Systems) detect and avoid (DAA) systems. Technologies to enable UAS with less available Size, Weight, and Power (SWaP) will be considered. A white paper is in development for what topics and issues need to be addressed to develop DAA requirements for low SWAP surveillance systems. This briefing will document the issues to be investigated in SC-228. It will also serve as a review with the committee to get feedback so the white paper can be written and finalized. These topics and issues are not necessarily all the things that NASA will contribute to SC-228 during Phase 2, but what the overall committee needs to accomplish. A portion of the work will be in NASA's UAS in the NAS (National Airspace System) project plan.

  9. Size distribution of alkyl amines in continental particulate matter and their online detection in the gas and particle phase

    Directory of Open Access Journals (Sweden)

    T. C. VandenBoer

    2011-05-01

    Full Text Available An ion chromatographic method is described for the quantification of the simple alkyl amines: methylamine (MA, dimethylamine (DMA, trimethylamine (TMA, ethylamine (EA, diethylamine (DEA and triethylamine (TEA, in the ambient atmosphere. Limits of detection (3σ are in the tens of pmol range for all of these amines, and good resolution is achieved for all compounds except for TMA and DEA. The technique was applied to the analysis of time-integrated samples collected using a micro-orifice uniform deposition impactor (MOUDI with ten stages for size resolution of particles with aerodynamic diameters between 56 nm and 18 μm. In eight samples from urban and rural continental airmasses, the mass loading of amines consistently maximized on the stage corresponding to particles with aerodynamic diameters between 320 and 560 nm. The molar ratio of amines to ammonium (R3NH+/NH4+ in fine aerosol ranged between 0.005 and 0.2, and maximized for the smallest particle sizes. The size-dependence of the R3NH+/NH4+ ratio indicates differences in the relative importance of the processes leading to the incorporation of amines and ammonia into secondary particles. The technique was also used to make simultaneous hourly online measurements of amines in the gas phase and in fine particulate matter using an Ambient Ion Monitor Ion Chromatograph (AIM-IC. During a ten day campaign in downtown Toronto, DMA, TMA + DEA, and TEA were observed to range from below detection limit to 2.7 ppt in the gas phase. In the particle phase, MAH+ and TMAH+ + DEAH+ were observed to range from below detection limit up to 15 ng m−3. The presence of detectable levels of amines in the particle phase corresponded to periods with higher relative humidity and higher mass loadings of nitrate. While the hourly measurements made using the AIM-IC provide data that can

  10. Optical properties of hydrothermally synthesized TGA-capped CdS nanoparticles: controlling crystalline size and phase

    Science.gov (United States)

    Tavakoli Banizi, Zoha; Seifi, Majid

    2017-10-01

    TGA-capped CdS nanoparticles were obtained in the presence of thioglycolic acid (TGA) as capping agent via a facile hydrothermal method at relatively low temperature and over a short duration. As-synthesized TGA-capped CdS nanoparticles were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, photoluminescence spectroscopy, Ultraviolet-visible spectroscopy and energy-dispersive x-ray spectroscopy. The products had spherical shapes, although their crystalline size and phase was dependent on temperature and time of the reaction. Photoluminescence spectra showed that the fluorescence intensity decreased when increasing the reaction time and temperature.

  11. Effect of kaolin particle size and loading on the characteristics of kaolin ceramic support prepared via phase inversion technique

    Directory of Open Access Journals (Sweden)

    Siti Khadijah Hubadillah

    2016-06-01

    Full Text Available In this study, low cost ceramic supports were prepared from kaolin via phase inversion technique with two kaolin particle sizes, which are 0.04–0.6 μm (denoted as type A and 10–15 μm (denoted as type B, at different kaolin contents ranging from 14 to 39 wt.%, sintered at 1200 °C. The effect of kaolin particle sizes as well as kaolin contents on membrane structure, pore size distribution, porosity, mechanical strength, surface roughness and gas permeation of the support were investigated. The support was prepared using kaolin type A induced asymmetric structure by combining macroporous voids and sponge-like structure in the support with pore size of 0.38 μm and 1.05 μm, respectively, and exhibited ideal porosity (27.7%, great mechanical strength (98.9 MPa and excellent gas permeation. Preliminary study shows that the kaolin ceramic support in this work is potential to gas separation application at lower cost.

  12. Toxicity of iron-based nanoparticles to green algae: Effects of particle size, crystal phase, oxidation state and environmental aging.

    Science.gov (United States)

    Lei, Cheng; Zhang, Luqing; Yang, Kun; Zhu, Lizhong; Lin, Daohui

    2016-11-01

    With the increasing environmental application and discharge of iron-based nanoparticles (NPs), a comprehensive understanding of their fate and ecotoxicological effect in the aquatic environment is very urgent. In this study, toxicities of 4 zero-valent iron NPs (nZVI) of different sizes, 2 Fe 2 O 3 NPs of different crystal phases, and 1 type of Fe 3 O 4 NPs to a green alga (Chlorella pyrenoidosa) were investigated, with a focus on the effects of particle size, crystal phase, oxidation state, and environmental aging. Results show that the algal growth inhibition of nZVI increased significantly with decreasing particle size; with similar particle sizes (20-30 nm), the algal growth inhibition decreased with oxidation of the NPs with an order of nZVI > Fe 3 O 4 NPs > Fe 2 O 3 NPs, and α-Fe 2 O 3 NPs presented significantly higher toxicity than γ-Fe 2 O 3 NPs. The NP-induced oxidative stress was the main toxic mechanism, which could explain the difference in algal toxicity of the NPs. The NP-cell heteroagglomeration and physical interactions also contributed to the nanotoxicity, whereas the effect of NP dissolution was negligible. The aging in distilled water and 3 surface water samples for 3 months increased surface oxidation of the iron-based NPs especially nZVI, which decreased the toxicity to algae. These findings will be helpful for the understanding of the fate and toxicity of iron-based NPs in the aquatic environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Pressing induced polymorphic phase transition in submicron-sized gamma-HMX

    Science.gov (United States)

    Moore, David; Lee, Kien-Yin

    2007-06-01

    Submicron HMX has been produced and characterized to be less sensitive than impact standard HMX in small-scale sensitivity tests. The sm-HMX was found to be the gamma polymorph and to be stable under ambient conditions for at least a year. Pressing of sm-HMX in a small diameter pellet press at pressures from 10 000 psi to 31 000 psi and 1 to 5 minute hold times was found to promote the gamma to beta polymorphic phase transition. The fraction converted and rate of conversion versus time after pellet removal from the press were found to fit a sigmoidal curve, indicating nucleation and growth as a possible polymorphic transition mechanism.

  14. Measurement of the size of the isoplanatic patch using a phase-correcting telescope

    Energy Technology Data Exchange (ETDEWEB)

    Pollaine, S.; Buffington, A.; Crawford, F.S.

    1979-01-01

    In the presence of several-arc-second seeing at Mt. Wilson observatory, a flexible-mirror image-sharpening telescope produced diffraction-limited (0.5 arc s) images of the primary stars in the double star systems of Castor (..cap alpha.. Gem), Algieba (..gamma.. Leo) and Almach (..gamma.. And). The images of both the primary and the companion star were simultaneously sharpened for Castor (separation 2 arc s ) and Algieba (4 arc s) but not for Almach (10 arc s). Thus the size of the isoplanatic patch lay between 4 and 10 arc s. Using a simple model, we conclude that the bulk of the turbulent air responsible for the seeing lay between 1.1 and 1.7 km above ground.

  15. Determination of filter pore size for use in HB line phase II production of plutonium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Shehee, T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Crowder, M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rudisill, T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-08-01

    H-Canyon and HB-Line are tasked with the production of plutonium oxide (PuO2) from a feed of plutonium (Pu) metal. The PuO2 will provide feed material for the Mixed Oxide (MOX) Fuel Fabrication Facility. After dissolution of the Pu metal in H-Canyon, plans are to transfer the solution to HB-Line for purification by anion exchange. Anion exchange will be followed by plutonium(IV) oxalate precipitation, filtration, and calcination to form PuO2. The filtrate solutions, remaining after precipitation, contain low levels of Pu ions, oxalate ions, and may include solids. These solutions are transferred to H-Canyon for disposition. To mitigate the criticality concern of Pu solids in a Canyon tank, past processes have used oxalate destruction or have pre-filled the Canyon tank with a neutron poison. The installation of a filter on the process lines from the HB-Line filtrate tanks to H-Canyon Tank 9.6 is proposed to remove plutonium oxalate solids. This report describes SRNL’s efforts to determine the appropriate pore size for the filters needed to perform this function. Information provided in this report aids in developing the control strategies for solids in the process.

  16. Effect of particle size and strain on phase stability of (Li{sub 0.06} Na{sub 0.94}) NbO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, S. K., E-mail: skmsspd@barc.gov.in; Shinde, A. B.; Krishna, P. S. R. [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai-40085 (India)

    2014-05-07

    Alkaline niobates are most suitable and excellent candidates for lead free piezoceramics, as they exhibit morphotropic phase boundary and have ultra-large piezoresponse similar to them. We provide direct experimental evidence of ferroelectric to paraelectric phase transition in (Li{sub 0.06} Na{sub 0.94})NbO{sub 3} with reduction of particle size using a combination of x-ray and neutron powder diffraction techniques at room temperature. Detailed Rietveld analyses of x-ray data show variation of particle sizes from micrometer to nanometer for sintered, calcined, and ball milled powders. The ferroelectric orthorhombic phase for micron sized powder (∼1.17 μm) is found to transform to paraelectric phase by reducing particle size to ∼10.8 nm. The crystal structure of paraelectric phase has been identified with tetragonal symmetry (P4{sub 2}/mmc) and is found to be a post perovskite phase. The low temperature neutron diffraction studies on the powders with different particle sizes reveal that orthorhombic to rhombohedral phase transition gets suppressed with reducing particle size.

  17. The Effects and Role of Polyvinylpyrrolidone on the Size and Phase Composition of Iron Oxide Nanoparticles Prepared by a Modified Sol-Gel Method

    National Research Council Canada - National Science Library

    Marcela F. Silva; Luiz A. S. de Oliveira; Mariani A. Ciciliati; Michele K. Lima; Flávio F. Ivashita; Daniela M. Fernandes de Oliveira; Ana Adelina W. Hechenleitner; Edgardo A. G. Pineda

    2017-01-01

    ...) aqueous solution in various Fe3+ : PVP monomer ratios. Analysis of X-ray diffraction was obtained to evaluate the crystalline state, average crystallite size, and composition of iron oxide phases...

  18. Background field removal technique using regularization enabled sophisticated harmonic artifact reduction for phase data with varying kernel sizes.

    Science.gov (United States)

    Kan, Hirohito; Kasai, Harumasa; Arai, Nobuyuki; Kunitomo, Hiroshi; Hirose, Yasujiro; Shibamoto, Yuta

    2016-09-01

    An effective background field removal technique is desired for more accurate quantitative susceptibility mapping (QSM) prior to dipole inversion. The aim of this study was to evaluate the accuracy of regularization enabled sophisticated harmonic artifact reduction for phase data with varying spherical kernel sizes (REV-SHARP) method using a three-dimensional head phantom and human brain data. The proposed REV-SHARP method used the spherical mean value operation and Tikhonov regularization in the deconvolution process, with varying 2-14mm kernel sizes. The kernel sizes were gradually reduced, similar to the SHARP with varying spherical kernel (VSHARP) method. We determined the relative errors and relationships between the true local field and estimated local field in REV-SHARP, VSHARP, projection onto dipole fields (PDF), and regularization enabled SHARP (RESHARP). Human experiment was also conducted using REV-SHARP, VSHARP, PDF, and RESHARP. The relative errors in the numerical phantom study were 0.386, 0.448, 0.838, and 0.452 for REV-SHARP, VSHARP, PDF, and RESHARP. REV-SHARP result exhibited the highest correlation between the true local field and estimated local field. The linear regression slopes were 1.005, 1.124, 0.988, and 0.536 for REV-SHARP, VSHARP, PDF, and RESHARP in regions of interest on the three-dimensional head phantom. In human experiments, no obvious errors due to artifacts were present in REV-SHARP. The proposed REV-SHARP is a new method combined with variable spherical kernel size and Tikhonov regularization. This technique might make it possible to be more accurate backgroud field removal and help to achive better accuracy of QSM. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Using large eddy simulations to reveal the size, strength, and phase of updraft and downdraft cores of an Arctic mixed-phase stratocumulus cloud

    Science.gov (United States)

    Roesler, Erika L.; Posselt, Derek J.; Rood, Richard B.

    2017-04-01

    Three-dimensional large eddy simulations (LES) are used to analyze a springtime Arctic mixed-phase stratocumulus observed on 26 April 2008 during the Indirect and Semi-Direct Aerosol Campaign. Two subgrid-scale turbulence parameterizations are compared. The first scheme is a 1.5-order turbulent kinetic energy (1.5-TKE) parameterization that has been previously applied to boundary layer cloud simulations. The second scheme, Cloud Layers Unified By Binormals (CLUBB), provides higher-order turbulent closure with scale awareness. The simulations, in comparisons with observations, show that both schemes produce the liquid profiles within measurement variability but underpredict ice water mass and overpredict ice number concentration. The simulation using CLUBB underpredicted liquid water path more than the simulation using the 1.5-TKE scheme, so the turbulent length scale and horizontal grid box size were increased to increase liquid water path and reduce dissipative energy. The LES simulations show this stratocumulus cloud to maintain a closed cellular structure, similar to observations. The updraft and downdraft cores self-organize into a larger meso-γ-scale convective pattern with the 1.5-TKE scheme, but the cores remain more isotropic with the CLUBB scheme. Additionally, the cores are often composed of liquid and ice instead of exclusively containing one or the other. These results provide insight into traditionally unresolved and unmeasurable aspects of an Arctic mixed-phase cloud. From analysis, this cloud's updraft and downdraft cores appear smaller than other closed-cell stratocumulus such as midlatitude stratocumulus and Arctic autumnal mixed-phase stratocumulus due to the weaker downdrafts and lower precipitation rates.

  20. Effects of Combined High Hydrostatic Pressure and Dense Phase Carbon Dioxide on the Activity, Structure and Size of Polyphenoloxidase.

    Science.gov (United States)

    Duong, Trang; Balaban, Murat; Perera, Conrad

    2015-11-01

    High hydrostatic pressure (HHP) may activate undesirable enzymes such as polyphenoloxidase (PPO). Carbon dioxide (CO2 ) addition to HHP could increase enzyme inactivation. We investigated the inactivation of combined HHP and dense phase carbon dioxide process on activity, secondary conformation and size of pure PPO from mushroom. Solutions (2.35μM, in phosphate buffer pH 6.8) were treated with HHP alone (HHP), or 3.6% w/w of CO2 was injected into the package (HHP+CO2). Treatment conditions were 600 MPa, 20 °C, for 1, 3, 5, 7, and 9 min. HHP+CO2 treatment significantly decreased residual enzyme activity (REA) to 30% to 12% after 1 to 9 min, respectively, whereas only HHP had no significant effect. Both HHP and HHP+CO2 treatments caused changes in secondary conformations, however HHP+CO2 changes were more extensive. Alpha-helix fractions were reduced by 32% and 41%, while β sheet, turn and unordered increased by 63% and 213%, 100% and 71%, and 118% and 82% for HHP and HHP+CO2, respectively after 9 min. The protein size in HHP+CO2 samples was 5- to 6-fold larger than that of Control and HHP treatment, and this increase was inversely correlated with REA. The best inactivation kinetics of HHP+CO2 model was the 2-fractional model with 2 simultaneous 1st-order steps, contributing 70% and 30% to original enzyme activity, with k(labile) = 12.15 min(-1) and k(stable) = 0.07 min(-1), respectively. No recovery in activity, secondary conformation and size in all samples were observed after 1-mo storage. Addition of CO2 in HHP treatment can improve enzyme inactivation, and therefore product shelf-life and quality. High hydrostatic pressure (HHP) achieves the safety of foods as a nonthermal method, but it may activate undesirable enzymes resulting in short shelf life due to, for example flavor and color changes. Our study determined that addition of CO2 to HHP has significant effects on enzyme inactivation, secondary conformational and molecular size changes of mushroom PPO

  1. The effect of K-na co-doping on the formation and particle size of Bi-2212 phase

    Energy Technology Data Exchange (ETDEWEB)

    Kır, M. Ebru [Department of Physics, Faculty of Arts and Sciences, Mersin University, Çiftlikköy, 33343 Mersin (Turkey); Özkurt, Berdan, E-mail: berdanozkurt@mersin.edu.tr [Department of Physics, Faculty of Arts and Sciences, Mersin University, Çiftlikköy, 33343 Mersin (Turkey); Department of Energy Systems Engineering, Faculty of Tarsus Technology, Mersin University, Mersin (Turkey); Advanced Technology Research and Application Center, Mersin University, Yenişehir, TR-33343 Mersin (Turkey); Aytekin, M. Ersin [Advanced Technology Research and Application Center, Mersin University, Yenişehir, TR-33343 Mersin (Turkey)

    2016-06-01

    Superconducting K-Na co-doped Bi{sub 2}Sr{sub 2}K{sub x}Ca{sub 1}Cu{sub 1.75}Na{sub 0.25}O{sub y} (x=0, 0.05, 0.1 and 0.25) ceramics are prepared by a solid-state reaction method. It is clearly determined from XRD data that the characteristic peaks of Bi-2212 phase are observed in all samples. The resistivity measurements show that T{sub c} (onset) values is gradually increasing as K content is increased. It is also found that K-Na co-doping influence the grain sizes for Bi-2212 phase significantly. The critical current densities as a function of magnetic field have been calculated from M–H hysteresis loops of samples according to Bean's critical model, indicating that K-Na co-doping cause higher J{sub c} values than the pure ones.

  2. Phase diagrams of magnetic state transformations in multiferroic composites controlled by size, shape and interfacial coupling strain

    Science.gov (United States)

    Sheng, Qiang; Liu, X. L.; Chen, W. J.; Xiong, W. M.; Jiang, G. L.; Zheng, Yue

    2017-10-01

    This work aims to give a comprehensive view of magnetic state stability and transformations in PZT-film/FeGa-dot multiferroic composite systems due to the combining effects of size, shape and interfacial coupling strain. It is found that the stable magnetic state of the FeGa nanodots is not only a function of the size and shape of the nanodot but also strongly sensitive to the interfacial coupling strain modified by the polarization state of PZT film. In particular, due to the large magnetostriction of FeGa, the phase boundaries between different magnetic states (i.e., in-plane/out-of-plane polar states, and single-/multi-vortex states) of FeGa nanodots can be effectively tuned by the polarization-mediated strain. Fruitful strain-mediated transformation paths of magnetic states including those between states with different orderings (i.e., one is polar and the other is vortex), as well as those between states with the same ordering (i.e., both are polar or both are vortex) have been revealed in a comprehensive view. Our result sheds light on the potential of utilizing electric field to induce fruitful magnetic state transformation paths in multiferroic film-dot systems towards a development of novel magnetic random access memories.

  3. Phase diagrams of magnetic state transformations in multiferroic composites controlled by size, shape and interfacial coupling strain

    Directory of Open Access Journals (Sweden)

    Qiang Sheng

    2017-10-01

    Full Text Available This work aims to give a comprehensive view of magnetic state stability and transformations in PZT-film/FeGa-dot multiferroic composite systems due to the combining effects of size, shape and interfacial coupling strain. It is found that the stable magnetic state of the FeGa nanodots is not only a function of the size and shape of the nanodot but also strongly sensitive to the interfacial coupling strain modified by the polarization state of PZT film. In particular, due to the large magnetostriction of FeGa, the phase boundaries between different magnetic states (i.e., in-plane/out-of-plane polar states, and single-/multi-vortex states of FeGa nanodots can be effectively tuned by the polarization-mediated strain. Fruitful strain-mediated transformation paths of magnetic states including those between states with different orderings (i.e., one is polar and the other is vortex, as well as those between states with the same ordering (i.e., both are polar or both are vortex have been revealed in a comprehensive view. Our result sheds light on the potential of utilizing electric field to induce fruitful magnetic state transformation paths in multiferroic film-dot systems towards a development of novel magnetic random access memories.

  4. Direct deposition of gas phase generated aerosol gold nanoparticles into biological fluids--corona formation and particle size shifts.

    Directory of Open Access Journals (Sweden)

    Christian R Svensson

    Full Text Available An ongoing discussion whether traditional toxicological methods are sufficient to evaluate the risks associated with nanoparticle inhalation has led to the emergence of Air-Liquid interface toxicology. As a step in this process, this study explores the evolution of particle characteristics as they move from the airborne state into physiological solution. Airborne gold nanoparticles (AuNP are generated using an evaporation-condensation technique. Spherical and agglomerate AuNPs are deposited into physiological solutions of increasing biological complexity. The AuNP size is characterized in air as mobility diameter and in liquid as hydrodynamic diameter. AuNP:Protein aggregation in physiological solutions is determined using dynamic light scattering, particle tracking analysis, and UV absorption spectroscopy. AuNPs deposited into homocysteine buffer form large gold-aggregates. Spherical AuNPs deposited in solutions of albumin were trapped at the Air-Liquid interface but was readily suspended in the solutions with a size close to that of the airborne particles, indicating that AuNP:Protein complex formation is promoted. Deposition into serum and lung fluid resulted in larger complexes, reflecting the formation of a more complex protein corona. UV absorption spectroscopy indicated no further aggregation of the AuNPs after deposition in solution. The corona of the deposited AuNPs shows differences compared to AuNPs generated in suspension. Deposition of AuNPs from the aerosol phase into biological fluids offers a method to study the protein corona formed, upon inhalation and deposition in the lungs in a more realistic way compared to particle liquid suspensions. This is important since the protein corona together with key particle properties (e.g. size, shape and surface reactivity to a large extent may determine the nanoparticle effects and possible translocation to other organs.

  5. Effect of Mo Dispersion Size and Water Vapor on Oxidation of Two-Phase Directionally Solidified NiAl-9Mo In-Situ Composites

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Michael P [ORNL; Bei, Hongbin [ORNL; Meisner, Roberta Ann [ORNL; Lance, Michael J [ORNL; Tortorelli, Peter F [ORNL

    2014-01-01

    Oxidation of two-phase NiAl-9Mo eutectics with 3 different growth rates/2nd phase Mo dispersion sizes were investigated at 900 C in air and air with 10% water vapor. Good oxidation resistance via alumina formation was observed in dry air, with Mo volatilization loss minimized by fine submicron Mo dispersions. However, extensive Mo volatilization and in-place internal oxidation of prior Mo phase regions was observed in wet air oxidation. Ramifications of this phenomenon for the development of multi-phase high-temperature alloys are discussed

  6. Effect of process parameters on the phase formation, particle size and magnetic properties of MnBi nanoparticles prepared by mechanochemical synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Rama Rao, N.V., E-mail: nvrrao@udel.edu; Hadjipanayis, G.C.

    2014-12-15

    Highlights: • Process parameters plays major role in controlling particle size, phase formation and magnetic properties. • Increase of the dispersant amount helps to decrease the particle size and make separated particles. • MnBi phase formation increases as the heat-treatment temperature increases. • Hc and Ms values are obtained in the range of 11–18.2 kOe and 13–32 emu/g, respectively. • Optimum magnetic properties with smaller particle size were obtained with 30 wt.% of CaO and at lower heat-treatment temperature. - Abstract: Nanoparticles of MnBi are obtained from Bi{sub 2}O{sub 3} and Mn by mechanochemical synthesis. The effect of excess dispersant (CaO) in mechanochemical synthesis and the temperature of subsequent thermal treatment on phase formation, particle size and magnetic properties of MnBi nanoparticles is investigated by means of X-ray diffraction analysis, scanning electron microscopy and magnetometry. With increase of excess dispersant, the average particle size decreases and the particles are observed to be more separated. Saturation magnetization (M{sub s}) was found to decrease with increase of excess dispersant, while the coercivity (H{sub c}) increases with the increase of dispersant up to 40 wt.% and thereafter it decreases. The formation of MnBi phase increases as the heat-treatment temperature is increased; however, the average particle size increases from nano to micrometer (200 nm to 2 μm)

  7. A New Method for Determining the Nanocrystallite Size Distribution in Systems Where Chemical Reaction between Solid and a Gas Phase Occurs

    Directory of Open Access Journals (Sweden)

    Rafał Pelka

    2013-01-01

    Full Text Available The proposed method, based on measuring the chemical reaction rate in solid phase, is, therefore, limited to such systems where reaction between nanocrystalline materials and a gas phase occurs. Additionally, assumptions of the model of reaction between nanocrystalline materials and a gas phase, where the surface chemical reaction rate is the rate limiting step, are used. As an example of such a reaction, nitriding (with ammonia of the prereduced industrial iron catalysts for ammonia synthesis of different average crystallite sizes was used. To measure the reaction rate, the differential reactor equipped with systems for thermogravimetric measurements and analysis of the chemical composition of the gas phase was used. The crystallites mass and size distributions for the analyzed samples of catalyst were determined.

  8. Hydrodynamic features of centrifugal contactor separators; experimental studies on liquid hold-up, residence time distribution, phase behavior and drop size distributions

    NARCIS (Netherlands)

    Schuur, Boelo; Kraai, G.N.; Winkelman, J.G.N.; Heeres, H.

    2012-01-01

    The liquid hold-up, residence time distributions (RTD), drop size distributions and continuous/dispersed phase for a typical centrifugal contactor separator (CCS) of the type CINC V02 were determined experimentally for various L-L systems. The hold-up ratio of the different solvents was mainly a

  9. Hydrodynamic features of centrifugal contactor separators : Experimental studies on liquid hold-up, residence time distribution, phase behavior and drop size distributions

    NARCIS (Netherlands)

    Schuur, Boelo; Kraai, Gerard N.; Winkelman, Jozef G. M.; Heeres, Hero J.

    The liquid hold-up, residence time distributions (RTD), drop size distributions and continuous/dispersed phase for a typical centrifugal contactor separator (CCS) of the type CINC V02 were determined experimentally for various L-L systems. The hold-up ratio of the different solvents was mainly a

  10. Optimizing Preparation of Micron SiO2-based Phase Change and Humidity Controlling Composites with Uniform Particle Size Distribution Based on RBF Neural Network

    Directory of Open Access Journals (Sweden)

    ZHANG Hao

    2017-08-01

    Full Text Available With SiO2 as the carrier, decanoic acid-palmitic acid as a phase change material,the micron SiO2-based phase change and humidity controlling composite materials were prepared by sol-gel method. The scheme was optimized by uniform design in a combination with RBF neural network to optimizing preparation of micron SiO2-based phase change and humidity controlling composite materials. The performance of micron SiO2-based phase change and humidity controlling composite materials with optimal uniform particle size distribution were tested and characterized. The results show that RBF neural network has the best approximation effect, when spread is 0.5; optimization technology parameters are solution pH value 4.27, amount of deionized water (mole ratio between deionized water and tetraethyl orthosilicate is 8.58, amount of absolute alcohol (mole ratio between absolute alcohol and tetraethyl orthosilicate is 4.83 and ultrasonic wave power is 316W; micron SiO2-based phase change and humidity controlling composite materials with optimal uniform particle size distribution' d10 is 383.51nm, d50 is 511.63nm and d90 is 658.76nm, measured value of d90-d10 is 275.25nm, the measured value and the predicted value are in good agreement (relative error is -2.64%; micron SiO2-based phase change and humidity controlling composite materials with optimal uniform particle size distribution' equilibrium moisture content in the relative humidity of 40%-60% is 0.0925-0.1493g/g, phase transition temperature is 20.02-23.45℃ and phase change enthalpy is 54.06-60.78J/g.

  11. Surface and finite size effects impact on the phase diagrams, polar, and dielectric properties of (Sr,Bi)Ta{sub 2}O{sub 9} ferroelectric nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Eliseev, E. A.; Fomichov, Y. M.; Glinchuk, M. D. [Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, Krjijanovskogo 3, 03142 Kyiv (Ukraine); Semchenko, A. V.; Sidsky, V. V. [F. Skorina Gomel State University, Sovetskaya 104, Gomel 246019 (Belarus); Kolos, V. V. [JSC “INTEGRAL,” Kazintsa 121A, Minsk 220108 (Belarus); Pleskachevsky, Yu. M. [V. A. Belyi Metal-Polymer Research Institute, National Academy of Sciences, Gomel (Belarus); Silibin, M. V., E-mail: sil-m@mail.ru, E-mail: anna.n.morozovska@gmail.com [National Research University of Electronic Technology “MIET,” Bld. 1, Shokin Square, 124498 Moscow (Russian Federation); Morozovsky, N. V.; Morozovska, A. N., E-mail: sil-m@mail.ru, E-mail: anna.n.morozovska@gmail.com [Institute of Physics, National Academy of Sciences of Ukraine, 46, Pr. Nauky, 03028 Kyiv (Ukraine)

    2016-05-28

    In the framework of the thermodynamic approach Landau-Ginzburg-Devonshire (LGD) combined with the equations of electrostatics, we investigated the effect of polarization surface screening on finite size effects of the phase diagrams, polar, and dielectric properties of ferroelectric nanoparticles of different shapes. We obtained and analyzed the analytical results for the dependences of the ferroelectric phase transition temperature, critical size, spontaneous polarization, and thermodynamic coercive field on the shape and size of the nanoparticles. The pronounced size effect of these characteristics on the scaling parameter, the ratio of the particle characteristic size to the length of the surface screening, was revealed. Also our modeling predicts a significant impact of the flexo-chemical effect (that is a joint action of flexoelectric effect and chemical pressure) on the temperature of phase transition, polar, and dielectric properties of nanoparticles when their chemical composition deviates from the stoichiometric one. We showed on the example of the stoichiometric nanosized SrBi{sub 2}Ta{sub 2}O{sub 9} particles that except the vicinity of the critical size, where the system splitting into domains has an important role, results of analytical calculation of the spontaneous polarization have a little difference from the numerical ones. We revealed a strong impact of the flexo-chemical effect on the phase transition temperature, polar, and dielectric properties of Sr{sub y}Bi{sub 2+x}Ta{sub 2}O{sub 9} nanoparticles when the ratio Sr/Bi deviates from the stoichiometric value of 0.5 within the range from 0.35 to 0.65. From the analysis of experimental data, we derived the parameters of the theory, namely, the coefficients of expansion of the LGD functional, the contribution of flexo-chemical effect, and the length of the surface screening.

  12. Phase I: energy conservation potential of Portland Cement particle size distribution control. Progress report, November 1978-January 1979

    Energy Technology Data Exchange (ETDEWEB)

    Helmuth, R.A.

    1979-03-01

    Progress is reported on the energy conservation potential of Portland cement particle size distribution control. Results of preliminary concrete tests, Series IIIa and Series IIIb, effects of particle size ranges on strength and drying shrinkage, are presented. Series IV, effects of mixing and curing temperature, tests compare the properties of several good particle size controlled cements with normally ground cements at low and high temperatures. The work on the effects of high alkali and high sulfate clinker cements (Series V) has begun.

  13. Toward industrial scale synthesis of ultrapure singlet nanoparticles with controllable sizes in a continuous gas-phase process

    NARCIS (Netherlands)

    Feng, J.; Biskos, G.; Schmidt-Ott, A.

    2015-01-01

    Continuous gas-phase synthesis of nanoparticles is associated with rapid agglomeration, which can be a limiting factor for numerous applications. In this report, we challenge this paradigm by providing experimental evidence to support that gas-phase methods can be used to produce ultrapure

  14. Measuring laves phase particle size and thermodynamic calculating its growth and coarsening behavior in P92 steels

    DEFF Research Database (Denmark)

    Yao, Bing-Yin; Zhou, Rong-Can; Fan, Chang-Xin

    2010-01-01

    The growth of Laves phase particles in three kinds of P92 steels were investigated. Laves phase particles can be easily separated and distinguished from the matrix and other particles by atom number contrast using comparisons of the backscatter electrons (BSE) images and the secondary electrons (...... attained between measurements in SEM and modeling by DICTRA. Ostwald ripening should be used for the coarsening calculation of Laves phase in P92 steels for time longer than 20000 h and 50000 h at 650°C and 600°C, respectively. © 2010 Chin. Soc. for Elec. Eng....

  15. Phase and size controllable synthesis of NaYbF4 nanocrystals in oleic acid/ionic liquid two-phase system for targeted fluorescent imaging of gastric cancer.

    Science.gov (United States)

    Pan, Liyuan; He, Meng; Ma, Jiebing; Tang, Wei; Gao, Guo; He, Rong; Su, Haichuan; Cui, Daxiang

    2013-01-01

    Upconversion nanocrystals with small size and strong fluorescent signals own great potential in applications such as biomolecule-labeling, in vivo tracking and molecular imaging. Herein we reported that NaYbF4: 25%Gd, 2%Tm upconversion nanocrystals with small size and strong fluorescent signals were controllably synthesized by oleic acid (OA)/ ionic liquid (IL) two-phase system for targeted fluorescent imaging of gastric cancer in vivo. The optimal synthesis condition of NaYbF4: 25%Gd, 2%Tm upconversion nanocrystals by OA/IL two-phase system was established, adding more metal ion such as Na(+) ion could facilitate the size control and crystal-phase transition, more importantly, markedly enhancing fluorescent intensity of beta-phase nanocrystals compared with traditional methods. Alpha-phase NaYbF4, 2%Tm upconversion nanocrystals with less than 10nm in diameter and beta-phase NaYbF4: 25%Gd, 2%Tm upconversion nanocrystals with 30 nm or so in diameter and strong fluorescent signals were obtained, these synthesized nanocrystals exhibited very low cytotoxicity. Folic acid-conjugated silica-modified beta-phase NaYbF4: 25%Gd, 2%Tm upconversion nanocrystals were prepared, could actively target gastric cancer tissues implanted into nude mice in vivo, and realized targeted fluorescent imaging. Folic acid-conjugated silica-modified NaYbF4: 25%Gd, 2%Tm upconversion nanocrystals show great potential in applications such as targeted near infared radiation fluorescent imaging, magnetic resonance imaging and targeted therapy of gastric cancer in the near future.

  16. Cation transfer across a hydrogel/organic phase: Effect of cation size, hydrophobicity and acid-base properties

    Energy Technology Data Exchange (ETDEWEB)

    Juarez, Ana V. [Departamento de Quimica Organica, IMBIV, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Yudi, Lidia M. [Departamento de Fisico Quimica, INFIQC, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Alvarez Igarzabal, Cecilia [Departamento de Quimica Organica, IMBIV, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Strumia, Miriam C., E-mail: mcs@fcq.unc.edu.a [Departamento de Quimica Organica, IMBIV, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2010-02-28

    The transfers of tetraethylammonium (TEA{sup +}) and protonated triflupromazine (HTFP{sup +}) through a hydrogel/liquid interface (g/o) and a liquid/liquid interface (w/o) were compared using cyclic voltammetry. After the two phases were put in contact, the behavior of each molecule was analyzed at different pH values and at different time points. The gel induces hydrophobic and electrostatic interactions with TEA{sup +} and HTFP{sup +}, shifting the peak potentials to more positive values. The diffusion coefficients, D, in both phases (g and w) at different pH values were calculated. In the case of TEA{sup +}, the D value remains constant in both systems. However, the D value of HTFP{sup +} is lower in the gel phase than in the liquid phase. HTFP{sup +} is transferred from the aqueous phase to the organic phase via a direct mechanism that involves coupled acid-base and partition processes. At the g/o interface, the coupled chemical reactions of HTFP{sup +} were inhibited by the drug/gel interaction. The results demonstrate that the g/o system could be used as a model to study the controlled release of charged drugs.

  17. Effect of grain size of parent phase on twinning modes of B19` martensite in an equiatomic Ti-Ni shape memory alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nishida, M. [Kumamoto Univ. (Japan). Dept. of Mater. Sci. and Resource Eng.; Itai, I. [Kumamoto Univ. (Japan). Dept. of Mater. Sci. and Resource Eng.; Kitamura, K. [Kumamoto Univ. (Japan). Dept. of Mater. Sci. and Resource Eng.; Chiba, A. [Kumamoto Univ. (Japan). Dept. of Mater. Sci. and Resource Eng.; Yamauchi, K. [Tokin Corp., Sendai (Japan)

    1995-12-01

    The effect of grain size of B2 parent phase on the twinning modes of B19` martensite in a Ti-50.0 at% Ni shape memory alloy has been studied. The grain size of parent phase was controlled from submicrons to several ten microns by cold-rolling and subsequent annealing. (001) compound twins were dominantly observed in the grain less than 4 {mu}m in diameter, although the (001) compound twinning did not give a solution to the phenomenological crystallographic theory. The triangular self-accommodating morphology of the martensite variants consisting of left angle 011 right angle Type II twins which were theoretically and experimentally recognized as a lattice invariant shear of the present transformation appeared in the whole grain more than 4 {mu}m in diameter. The formation mechanism of the (001) compound twinning in the fine grain is also discussed. (orig.).

  18. Scattering Properties of Jovian Tropospheric Cloud Particles from Cassini/ISS: Mie Scattering Phase Function and Particle Size in the South Tropical Zone

    Science.gov (United States)

    Sato, Takao M.; Satoh, T.; Kasaba, Y.

    2010-10-01

    It is essential to know scattering properties (e.g., scattering phase function) of clouds for determination of vertical cloud structure. However, we cannot derive those from ground-based and Earth-orbit observations because of the limitation of solar phase angle as viewed from the Earth. Then, most previous studies have used the scattering phase function deduced from the Pioneer 10/IPP data (blue: 440 nm, red: 640nm) [Tomasko et al., 1978]. There are two shortcomings in the Pioneer scattering phase function. One is that we have to use this scattering phase function at red as a substitute for analyses of imaging photometry using CH4 bands (center: 727 and 890 nm), although clouds should have wavelength dependency. The other is that the red pass band of IPP was so broad (595-720 nm) that this scattering phase function in red just show wavelength-averaged scattering properties of clouds. To provide a new reference scattering phase function with wavelength dependency, we have analyzed the Cassini/ISS data in BL1 (451 nm), CB1 (619 nm), CB2 (750 nm), and CB3 (938 nm) over wide solar phase angles (3-141 degrees) during its Jovian flyby in 2000-2001. A simple cloud model which consists of a thin stratospheric haze, a semi-infinite cloud, and an intervening Rayleigh gas layers is adopted. Applying Mie theory to scattering by clouds, we deduce the scattering phase function of cloud and effective particle size in the South Tropical Zone. When we use the nominal value of reflective index for ammonia ice (Martonchik et al., 1984), we cannot obtain reasonable fit to the observed limb-darkening profiles. This would imply that we should consider possible effects on the impurity and/or the nonsphericiy of clouds. In this presentation, we will show detail model description and these results. Finally, we discuss scattering properties of clouds through comparison with previous works.

  19. Impact of size of region-of-interest on differentiation of renal cell carcinoma and renal cysts on multi-phase CT: Preliminary findings

    Energy Technology Data Exchange (ETDEWEB)

    Rosenkrantz, Andrew B., E-mail: Andrew.Rosenkrantz@nyumc.org [Department of Radiology, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016 (United States); Matza, Brent W.; Portnoy, Elie [Department of Radiology, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016 (United States); Melamed, Jonathan [Department of Pathology, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016 (United States); Taneja, Samir S. [Division of Urologic Oncology, Department of Urology, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016 (United States); Wehrli, Natasha E. [Department of Radiology, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016 (United States)

    2014-02-15

    Introduction: To assess impact of size of regions-of-interest (ROI) on differentiation of RCC and renal cysts using multi-phase CT, with focus on differentiating papillary RCC (pRCC) and cysts given known hypovascularity of pRCC. Methods: 99 renal lesions (23 pRCC, 47 clear-cell RCC, 7 chromophobe RCC, 22 cysts) underwent multi-phase CT. Subjective presence of visual enhancement was recorded for each lesion. Whole-lesion (WL) ROIs, and small (≤5 mm{sup 2}), medium (average size of small and large ROIs), and large (half of lesion diameter) peripherally located partial-lesion (PL) ROIs, were placed on non-contrast and nephrographic phases. Impact of ROI size in separating cysts from all RCC and from pRCC based on increased attenuation between phases was assessed using ROC analysis. Results: Visual enhancement was perceived in 96% of ccRCC, 61% of pRCC, and 9% of cysts. AUCs for separating all RCC and cysts for WL-ROI and small, medium, and large PL-ROIs were 91%, 96%, 91% and 93%, and among lesions without visible enhancement were 60%, 79%, 67% and 67%. AUCs for separating pRCC and cysts for WL-ROI and small, medium, and large PL-ROIs were 78%, 92%, 82% and 84%, and among lesions without visible enhancement were 64%, 88%, 69% and 69%. Conclusion: Small PL-ROIs had higher accuracy than WL-ROI or other PL-ROIs in separating RCC from cysts, with greater impact in differentiating pRCC from cysts and differentiating lesions without visible enhancement. Thus, when evaluating renal lesions using multi-phase CT, we suggest placing small peripheral ROIs for highest accuracy in distinguishing renal malignancy and benign cysts.

  20. One-Step, Facile and Ultrafast Synthesis of Phase- and Size-Controlled Pt-Bi Intermetallic Nanocatalysts through Continuous-Flow Microfluidics.

    Science.gov (United States)

    Zhang, Dongtang; Wu, Fuxiang; Peng, Manhua; Wang, Xiayan; Xia, Dingguo; Guo, Guangsheng

    2015-05-20

    Ordered intermetallic nanomaterials are of considerable interest for fuel cell applications because of their unique electronic and structural properties. The synthesis of intermetallic compounds generally requires the use of high temperatures and multiple-step processes. The development of techniques for rapid phase- and size-controlled synthesis remains a formidable challenge. The intermetallic compound Pt1Bi2 is a promising candidate catalyst for direct methanol fuel cells because of its high catalytic activity and excellent methanol tolerance. In this work, we explored a one-step, facile and ultrafast phase- and size-controlled process for synthesizing ordered Pt-Bi intermetallic nanoparticles (NPs) within seconds in microfluidic reactors. Single-phase Pt1Bi1 and Pt1Bi2 intermetallic NPs were prepared by tuning the reaction temperature, and size control was achieved by modifying the solvents and the length of the reaction channel. The as-prepared Pt-Bi intermetallic NPs exhibited excellent methanol tolerance capacity and high electrocatalytic activity. Other intermetallic nanomaterials, such as Pt3Fe intermetallic nanowires with a diameter of 8.6 nm and Pt1Sn1 intermetallic nanowires with a diameter of 6.3 nm, were also successfully synthesized using this method, thus demonstrating its feasibility and generality.

  1. Phase and size separations occurring during the injection of model pastes composed of β-tricalcium phosphate powder, glass beads and aqueous solutions.

    Science.gov (United States)

    Tadier, S; Galea, L; Charbonnier, B; Baroud, G; Bohner, M

    2014-05-01

    Glass beads a few hundred micrometers in size were added to aqueous β-tricalcium phosphate pastes to simulate the effect of porogens and drug-loaded microspheres on the injectability of calcium phosphate cements and putties. The composition of the pastes was monitored during the injection process to assess the effect of glass bead content, glass bead size and paste composition on the paste injectability. The results revealed that the injection process led to both liquid and glass bead segregations: the liquid flowed faster than the glass beads, which themselves flowed faster than the β-tricalcium phosphate microparticles. In fact, even the particle size distribution of the glass beads was modified during injection. These results reveal that a good design of multiphasic injectable pastes is essential to prevent phase separation. Copyright © 2013 Acta Materialia Inc. All rights reserved.

  2. Gas-particle phase partitioning and particle size distribution of chlorinated and brominated polycyclic aromatic hydrocarbons in haze.

    Science.gov (United States)

    Jin, Rong; Zheng, Minghui; Yang, Hongbo; Yang, Lili; Wu, Xiaolin; Xu, Yang; Liu, Guorui

    2017-12-01

    Chlorinated and brominated polycyclic aromatic hydrocarbons (Cl/Br-PAHs) are emerging semi-volatile organic pollutants in haze-associated particulate matter (PM). Their gas-particle phase partitioning and distribution among PM fractions have not been clarified. Clarification would increase understanding of atmospheric behavior and health risks of Cl/Br-PAHs. In this study, samples of the gas phase and 4 PM phases (aerodynamic diameters (dae) > 10 μm, 2.5-10 μm, 1.0-2.5 μm, and distribution indicated that the Cl/Br-PAHs tended to adhere to fine particles. Over 80% of the Cl-PAHs and 70% of the Br-PAHs were associated with fine PM (dae particle phase partitioning and PM distribution of Cl/Br-PAHs when heating of buildings was required, which was associated with haze events, were obviously different from those when heating was not required. The relationship between the logarithmic geometric mean diameters of the Cl/Br-PAH congeners and reciprocal of the temperature (1/T) suggested that low air temperatures during the heating period could lead to high proportions of Cl/Br-PAHs in the fine particles. Increased coal burning during the heating period also contributed to high Cl/Br-PAH loads in the fine particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Intraspecific Allometry of Basal Metabolic Rate : Relations with Body Size, Temperature, Composition, and Circadian Phase in the Kestrel, Falco tinnunculus

    NARCIS (Netherlands)

    Daan, Serge; Masman, Dirkjan; Strijkstra, Arjen; Verhulst, Simon

    1989-01-01

    The relationship between body size and basal metabolic rate (BMR) in homeotherms has been treated in the literature primarily by comparison between species of mammals or birds. This paper focuses on the intraindividual changes in BMR when body mass (W) varies with different maintenance regimens. BMR

  4. Investigation of the Influence of Sucrose and Cholesterol on the Phase Transition Temperature of nanoliposomal formulation besides using particle size Reduction Techniques (Ultrasonication/High Pressure Homogenization

    Directory of Open Access Journals (Sweden)

    Z Malaei-Balasi

    2017-05-01

    Full Text Available Introduction: The successful application of nanoliposoms as an effective drug delivery system depends on their stability in the medium. In this article, influence of additive materials such as cholesterol and sucrose besides two natural and synthesized phospholipids have been investigated. Methods: In the present study, designing and synthesis of nanoliposomal formulations were prepared using thin film method. This liposomal suspension was downsized by two methods, the high-pressure homogenizer and ultrasound to form small unilamellar vesicles. The size distributions, zeta potentials and phase transition temperature of formulations were all determined by a zetasizer and differential scanning calorimetry(DSC. In addition, the contribution of nanoliposomal formulation has been investigated by HPLC and FTIR methods. Results: Results of the DSC measurments indicated that incorporation of unsaturated phospholipid (SOY PC may cause phase separation with partial miscibility in the liposome bilayer containing of DPPG. The optimal nanoliposomal formulation was composed of (DPPC: CHOL: mPEG2000-DSPE with the mole percents equal to (83:15:2, respectively. In addition, sucrose has been used in the formulation with a total amounts six times greater than that of the lipids. The properties of optimized nanoliposome have been shown as the size average 104nm, zeta potential 8.04mv and phase transition temperature of lipid less than 37°C which were stable enough to be utilized for loading and releasing bioactives in body temperature. Conclusion: Finally the produced nanoliposomes were stable vesicles in the proper size, phase transition temperature and surface charge without any aggregation and fusion.

  5. Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation

    Science.gov (United States)

    Kopechek, Jonathan A.; Zhang, Peng; Burgess, Mark T.; Porter, Tyrone M.

    2012-01-01

    High-intensity focused ultrasound (HIFU) is used clinically to thermally ablate tumors. To enhance localized heating and improve thermal ablation in tumors, lipid-coated perfluorocarbon droplets have been developed which can be vaporized by HIFU. The vasculature in many tumors is abnormally leaky due to their rapid growth, and nanoparticles are able to penetrate the fenestrations and passively accumulate within tumors. Thus, controlling the size of the droplets can result in better accumulation within tumors. In this report, the preparation of stable droplets in a phase-shift nanoemulsion (PSNE) with a narrow size distribution is described. PSNE were synthesized by sonicating a lipid solution in the presence of liquid perfluorocarbon. A narrow size distribution was obtained by extruding the PSNE multiple times using filters with pore sizes of 100 or 200 nm. The size distribution was measured over a 7-day period using dynamic light scattering. Polyacrylamide hydrogels containing PSNE were prepared for in vitro experiments. PSNE droplets in the hydrogels were vaporized with ultrasound and the resulting bubbles enhanced localized heating. Vaporized PSNE enables more rapid heating and also reduces the ultrasound intensity needed for thermal ablation. Thus, PSNE is expected to enhance thermal ablation in tumors, potentially improving therapeutic outcomes of HIFU-mediated thermal ablation treatments. PMID:23007836

  6. Differences in estimates of size distribution of beryllium powder materials using phase contrast microscopy, scanning electron microscopy, and liquid suspension counter techniques

    Directory of Open Access Journals (Sweden)

    Day Gregory A

    2007-02-01

    Full Text Available Abstract Accurate characterization of the physicochemical properties of aerosols generated for inhalation toxicology studies is essential for obtaining meaningful results. Great emphasis must also be placed on characterizing particle properties of materials as administered in inhalation studies. Thus, research is needed to identify a suite of techniques capable of characterizing the multiple particle properties (i.e., size, mass, surface area, number of a material that may influence toxicity. The purpose of this study was to characterize the morphology and investigate the size distribution of a model toxicant, beryllium. Beryllium metal, oxides, and alloy particles were aerodynamically size-separated using an aerosol cyclone, imaged dry using scanning electron microscopy (SEM, then characterized using phase contrast microscopy (PCM, a liquid suspension particle counter (LPC, and computer-controlled SEM (CCSEM. Beryllium metal powder was compact with smaller sub-micrometer size particles attached to the surface of larger particles, whereas the beryllium oxides and alloy particles were clusters of primary particles. As expected, the geometric mean (GM diameter of metal powder determined using PCM decreased with aerodynamic size, but when suspended in liquid for LPC or CCSEM analysis, the GM diameter decreased by a factor of two (p

  7. Automated synthesis of a 96 product-sized library of triazole derivatives using a solid phase supported copper catalyst.

    Science.gov (United States)

    Jlalia, Ibtissem; Beauvineau, Claire; Beauvière, Sophie; Onen, Esra; Aufort, Marie; Beauvineau, Aymeric; Khaba, Eihab; Herscovici, Jean; Meganem, Faouzi; Girard, Christian

    2010-04-28

    This article deal with the parallel synthesis of a 96 product-sized library using a polymer-based copper catalyst that we developed which can be easily separated from the products by simple filtration. This gave us the opportunity to use this catalyst in an automated chemical synthesis station (Chemspeed ASW-2000). Studies and results about the preparation of the catalyst, its use in different solvent systems, its recycling capabilities and its scope and limitations in the synthesis of this library will be addressed. The synthesis of the triazole library and the very good results obtained will finally be discussed.

  8. Communication: Light driven remote control of microgels' size in the presence of photosensitive surfactant: Complete phase diagram

    Science.gov (United States)

    Schimka, Selina; Gordievskaya, Yulia D.; Lomadze, Nino; Lehmann, Maren; von Klitzing, Regine; Rumyantsev, Artem M.; Kramarenko, Elena Yu.; Santer, Svetlana

    2017-07-01

    Here we report on a light triggered remote control of microgel size in the presence of photosensitive surfactant. The hydrophobic tail of the cationic surfactant contains azobenzene group that undergoes a reversible photo-isomerization reaction from a trans- to a cis-state accompanied by a change in the hydrophobicity of the surfactant. We have investigated light assisted behaviour and the complex formation of the microgels with azobenzene containing surfactant over the broad concentrational range starting far below and exceeding several times of the critical micelle concentration (CMC). At small surfactant concentration in solution (far below CMC), the surfactant in the trans-state accommodates within the microgel causing its compaction, while the cis-isomer desorbs out of microgel resulting in its swelling. The process of the microgel size change can be described as swelling on UV irradiation (trans-cis isomerization) and shrinking on irradiation with blue light (cis-trans isomerization). However, at the surfactant concentrations larger than CMC, the opposite behaviour is observed: the microgel swells on blue irradiation and shrinks during exposure to UV light. We explain this behaviour theoretically taking into account isomer dependent micellization of surfactant within the microgels.

  9. Size- and intensity-dependent photoelectron spectra from gas-phase gold nanoparticles irradiated by intense femtosecond laser pulses

    Science.gov (United States)

    Powell, J.; Robatjazi, S. J.; Makhija, V.; Vajdi, A.; Li, X.; Malakar, Y.; Pearson, W. L.; Rudenko, A.; Sorensen, C.; Stierle, J.; Kling, M. F.

    2016-05-01

    Nanoparticles bridge the gap between atomic/molecular and bulk matter offering unique opportunities to study light interactions with complex systems, in particular, near-field enhancements and excitation of plasmons. Here we report on a systematic study of photoelectron emission from isolated gold nanoparticles irradiated by 800 nm, 25 fs laser pulses at 10-50 TW/ cm2 peak intensities. A combination of an aerodynamic lens nanoparticle injector, high-energy velocity-map imaging spectrometer and a high-speed, single-shot camera is employed to record shot by shot photoelectron emission patterns from individual particles. By sorting the recorded images according to the number of emitted electrons, we select the events from the regions of particular laser intensities within the laser focus, thus, essentially avoiding focal volume averaging. Using this approach, we study the intensity- and size-dependence of photoelectron energy and angular distributions for particle sizes ranging from 5 nm to 400 nm. This work is supported by NSF Award No. IIA-143049. JRML operations and personal are supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of BES, Office of Science, U. S. DOE.

  10. The embryonic phase and its implication in the hatchling size and condition of Atlantic bobtail squid Sepiola atlantica

    Science.gov (United States)

    Rodrigues, Marcelo; Guerra, Ángel; Troncoso, Jesús S.

    2011-06-01

    Early life stages of cephalopods are somewhat complex due to the life history strategy or species specificity of generalized ontogenetic patterns and processes. This work aimed to determine the time length of embryonic development at different temperatures, and if the egg size is a determinant of hatchling size in Sepiola atlantica d'Orbigny, 1839-1842. Successful hatching occurred in 98.5-100% of the eggs for each female. As seen in other coleoid cephalopods, temperature determines the amount of time for embryonic development in S. atlantica, and the obtained data were very similar to other coleoid cephalopods. Developmental times for temperatures at 13 ± 0.4°C, 18 ± 0.3°C and 16.4 ± 1.1°C were 61.8 ± 3.8, 22.6 ± 1.7 and 40.1 ± 4.8 days. The duration of embryonic development and hatchling mantle length was not strictly related. The egg volume was positively related to hatchling mantle length. Our results provide new records on the duration of embryogenesis and other information on reproductive patterns in this species. Some hatching and post-hatching behaviour are shown and discussed.

  11. Sonochemical synthesis and characterization of nano-sized zinc(II coordination complex as a precursor for the preparation of pure-phase zinc(II oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Maryam Ranjbar

    2017-01-01

    Full Text Available In current study, nanoparticles and single crystals of a Zn(II coordination complex, [Zn(dmphI2](1, {dmph=2,9-dimethyl-1,10-phenanthroline(neocuproine}, have been synthesized by the reaction of zinc(II acetate, KI and neocuproine as ligand in methanol using sonochemical and heat gradient methods, respectively. The nanostructure of 1 was characterized by scanning electron microscopy (SEM, X-ray powder diffraction (XRD, FT-IR spectroscopy and elemental analyses, and the structure of compound 1 was determined by single-crystal X-ray diffraction. The thermal stability of nano-sized 1 has been studied by thermogravimetric (TG and differential thermal analyses (DTA. Structural determination of compound 1 reveals the Zn(II ion is four-coordinated in a distorted tetrahedral configuration by two N atoms from a 2,9-dimethyl-1,10-Phenanthroline ligand and two terminal I atoms. The effect of supercritical condition on stability, size and morphology of nano-structured compound 1 has also been studied. The XRD pattern of the residue obtained from thermal decomposition of nano-sized compound 1 at 600 °C under air atmosphere provided pure phase of ZnO with the average particles size of about 31 nm.

  12. Lung injury induced by TiO2 nanoparticles depends on their structural features: size, shape, crystal phases, and surface coating.

    Science.gov (United States)

    Wang, Jiangxue; Fan, Yubo

    2014-12-03

    With the rapid development of nanotechnology, a variety of engineered nanoparticles (NPs) are being produced. Nanotoxicology has become a hot topic in many fields, as researchers attempt to elucidate the potential adverse health effects of NPs. The biological activity of NPs strongly depends on physicochemical parameters but these are not routinely considered in toxicity screening, such as dose metrics. In this work, nanoscale titanium dioxide (TiO2), one of the most commonly produced and widely used NPs, is put forth as a representative. The correlation between the lung toxicity and pulmonary cell impairment related to TiO2 NPs and its unusual structural features, including size, shape, crystal phases, and surface coating, is reviewed in detail. The reactive oxygen species (ROS) production in pulmonary inflammation in response to the properties of TiO2 NPs is also briefly described. To fully understand the potential biological effects of NPs in toxicity screening, we highly recommend that the size, crystal phase, dispersion and agglomeration status, surface coating, and chemical composition should be most appropriately characterized.

  13. Effect of hiatal hernia size and columnar segment length on the success of radiofrequency ablation for Barrett's esophagus: a single-center, phase II clinical trial.

    Science.gov (United States)

    Korst, Robert J; Santana-Joseph, Sobeida; Rutledge, John R; Antler, Arthur; Bethala, Vivian; DeLillo, Anthony; Kutner, Donald; Lee, Benjamin E; Pazwash, Haleh; Pittman, Robert H; Rahmin, Michael; Rubinoff, Mitchell

    2011-11-01

    Hiatal hernia is common in patients with Barrett's esophagus. We sought to evaluate the effect of hiatal hernia size and initial columnar segment length on the success of radiofrequency ablation of Barrett's esophagus. A phase II clinical trial was conducted aimed at evaluating the success of radiofrequency ablation in eradicating Barrett's esophagus. Success was defined as complete replacement of the columnar lining with squamous mucosa and lack of intestinal metaplasia using light microscopy. Hiatal hernia size and columnar segment length were measured endoscopically. Sixty-seven patients were accrued to the protocol. In the 55 patients who completed radiofrequency ablation (43 successes, 12 failures), the mean hiatal hernia size was 3.3 cm (range, 0-10 cm), and the mean columnar segment length was 5.4 cm (range, 1-18 cm). The median length of the columnar segment was 3 cm in the successful cases and 8.5 cm in the failed cases (P = .002). Although the median hiatal hernia size was identical in the successful and failed cases (3 cm, P = .38), the median hiatal hernia size was 7 cm (P = .001) in the 6 patients who experienced nonhealing after the initial ablation. Patients who were successfully ablated but had larger hiatal hernias and longer columnar segment lengths required significantly more radiofrequency ablation sessions than those with smaller hernias and shorter segments (P = .003 and P = .007, respectively). Patients with larger hiatal hernias and longer columnar segments are more likely to experience failure or nonhealing after radiofrequency ablation. These patients also require more radiofrequency ablation treatments to achieve successful eradication of Barrett's esophagus. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  14. Scattering Properties of Jovian Tropospheric Cloud Particles Inferred from Cassini/ISS: Mie Scattering Phase Function and Particle Size in South Tropical Zone III

    Science.gov (United States)

    Sato, T.; Satoh, T.; Kasaba, Y.

    2010-12-01

    nm), CB2 (750 nm), and CB3 (938 nm) over wide solar phase angles (3-141 degrees) during its Jovian flyby in 2000-2001. A simple cloud model which consists of a thin stratospheric haze, a semi-infinite cloud, and an intervening Rayleigh gas layers is adopted. Applying Mie theory to scattering by clouds, we deduce the scattering phase function of cloud and effective particle size in the South Tropical Zone. When we use the nominal value of reflective index for ammonia ice (Martonchik et al., 1984), we cannot obtain reasonable fit to the observed limb-darkening profiles. This would imply that we should consider possible effects on the impurity and/or the nonsphericiy of clouds. In this presentation, we will show detail model description and these results. Finally, we discuss scattering properties of clouds through comparison with previous works.

  15. Co-grinding significance for calcium carbonate-calcium phosphate mixed cement. Part I: effect of particle size and mixing on solid phase reactivity.

    Science.gov (United States)

    Tadier, S; Le Bolay, N; Rey, C; Combes, C

    2011-04-01

    In part I of this study we aim to evaluate and control the characteristics of the powders constituting the solid phase of a vaterite CaCO(3)-dicalcium phosphate dihydrate cement using a co-grinding process and to determine their impact on cement setting ability. An original methodology involving complementary analytical techniques was implemented to thoroughly investigate the grinding mechanism of separated or mixed reactive powders and the effects on solid phase reactivity. We showed that the association of both reactive powders during co-grinding improves the efficiency of this process in terms of the particle size decrease, thus making co-grinding adaptable to industrial development of the cement. For the first time the usefulness of horizontal attenuated total reflection Fourier transform infrared spectroscopy to follow the chemical setting reaction at 37°C in real time has been demonstrated. We point out the antagonist effects that co-grinding can have on cement setting: the setting time is halved; however, progress of the chemical reaction involving dissolution-reprecipitation is delayed by 30 min, probably due to the increased contact area between the reactive powders, limiting their hydration. More generally, we can take advantage of the co-grinding process to control powder mixing, size and reactivity and this original analytical methodology to better understand its effect on the phenomena involved during powder processing and cement setting, which is decisive for the development of multi-component cements. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. Sample size determination for the current strategy in oncology phase 3 trials that tests progression-free survival and overall survival in a two-stage design framework.

    Science.gov (United States)

    Nomura, Shogo; Hirakawa, Akihiro; Hamada, Chikuma

    2017-09-08

    The selection of progression-free survival (PFS) or overall survival (OS) as the most suitable primary endpoint in oncology phase 3 trials is currently under intense debate. Because of substantial limitations in the single use of PFS (or OS) as the primary endpoint, trial designs that include PFS and OS as co-primary endpoints are attracting increasing interest. In this paper, we report on the formulation of determining the sample size for a trial that sequentially tests PFS and OS by treating them as co-primary endpoints. Using a three-component model of OS, the proposed method overcomes the drawbacks of an existing method that requires unreasonable assumption of the exponential distribution for OS, although the hazard function is non-constant because effective subsequent therapy have prolonged post-progression survival in recent oncology trials. Alternative estimation method of hazard ratio for OS under a three-component mode is also discussed by checking the appropriateness of assuming proportionality of hazards for OS. In order to examine the performance of our proposed method, we performed three numerical studies using both simulated and actual data of cancer phase 3 trials. We find that the proposed method preserves a pre-specified target value of power with a feasible increment of trial scale.

  17. A size exclusion-reversed phase two dimensional-liquid chromatography methodology for stability and small molecule related species in antibody drug conjugates.

    Science.gov (United States)

    Li, Yi; Gu, Christine; Gruenhagen, Jason; Zhang, Kelly; Yehl, Peter; Chetwyn, Nik P; Medley, Colin D

    2015-05-08

    Antibody drug conjugates (ADCs) are complex therapeutic agents combining the specific targeting properties of antibodies and highly potent cytotoxic small molecule drugs to selectively eliminate tumor cells while limiting the toxicity to normal healthy tissues. One unique critical quality attribute of ADCs is the content of unconjugated small molecule drug present from either incomplete conjugation or degradation of the ADC. In this work, size exclusion chromatography (SEC) was coupled with reversed-phase (RP) HPLC in an online 2-dimensional chromatography format for identification and quantitation of unconjugated small molecule drugs and related small molecule impurities in ADC samples directly without sample preparation. The SEC method in the 1st dimension not only separated the small molecule impurities from the intact ADC, but also provided information about the size variants (monomer, dimer, aggregates, etc.) of the ADC. The small molecule peak from the SEC was trapped and sent to a RP-HPLC in the 2nd dimension to further separate and quantify the different small molecule impurities present in the ADC sample. This SEC-RP 2D-LC method demonstrated excellent precision (%RSDmolecule degradation products and aggregation of the conjugate were observed in the stability samples and the degradation pathways of the ADC were investigated. This 2D-LC method offers a powerful tool for ADC characterization and provides valuable information for conjugation and formulation development. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. High efficiency, narrow particle size distribution, sub-2 μm based macrocyclic glycopeptide chiral stationary phases in HPLC and SFC.

    Science.gov (United States)

    Barhate, Chandan L; Wahab, M Farooq; Breitbach, Zachary S; Bell, David S; Armstrong, Daniel W

    2015-10-22

    State of the art chiral chromatography still employs 3-5 μm bonded or immobilized chiral selectors in 10-25 cm columns. With the availability of 1.9 μm narrow particle size distribution (NPSD) silica, it is now possible to make ever shorter, high efficiency columns practical for sub-minute chiral separations. Three macrocyclic glycopeptides (teicoplanin, teicoplanin aglycone, and vancomycin) were bonded onto 1.9 μm NPSD particles. Such packed columns had ∼80% lower backpressure as compared to polydisperse (PD) 1.7 μm silica materials when using the same mobile phase. The decreased backpressure allowed for diminution of frictional heating and allowed for the use of the 1.9 μm NPSD particle based columns at high flow rates. The 1.9 μm NPSD particle based columns showed up to 190,000 plates m(-1) for chiral molecules and 210,000 plates m(-1) for achiral probes. Representative enantiomeric separations are shown for wide classes of compounds, including different types of amino acids, β-blockers, and pharmaceutically important heterocyclic compounds such as oxazolidinones. Applications in three liquid chromatography modes, namely, reversed phase, polar organic mode and normal phase chiral separations were shown with resolution values ranging from 1.5 to 5.7. Additionally, the same columns were used with supercritical fluid chromatography (SFC) for ultrafast separations. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. High Pressure Size Exclusion Chromatography (HPSEC) Determination of Dissolved Organic Matter Molecular Weight Revisited: Accounting for Changes in Stationary Phases, Analytical Standards, and Isolation Methods.

    Science.gov (United States)

    McAdams, Brandon C; Aiken, George R; McKnight, Diane M; Arnold, William A; Chin, Yu-Ping

    2018-01-16

    We reassessed the molecular weight of dissolved organic matter (DOM) determined by high pressure size exclusion chromatography (HPSEC) using measurements made with different columns and various generations of polystyrenesulfonate (PSS) molecular weight standards. Molecular weight measurements made with a newer generation HPSEC column and PSS standards from more recent lots are roughly 200 to 400 Da lower than initial measurements made in the early 1990s. These updated numbers match DOM molecular weights measured by colligative methods and fall within a range of values calculated from hydroxyl radical kinetics. These changes suggest improved accuracy of HPSEC molecular weight measurements that we attribute to improved accuracy of PSS standards and changes in the column packing. We also isolated DOM from wetlands in the Prairie Pothole Region (PPR) using XAD-8, a cation exchange resin, and PPL, a styrene-divinylbenzene media, and observed little difference in molecular weight and specific UV absorbance at 280 nm (SUVA 280 ) between the two solid phase extraction resins, suggesting they capture similar DOM moieties. PPR DOM also showed lower SUVA 280 at similar weights compared to DOM isolates from a global range of environments, which we attribute to oxidized sulfur in PPR DOM that would increase molecular weight without affecting SUVA 280 .

  20. One-step synthesis of single phase micro-sized BaFe{sub 12}O{sub 19} hexaplates via a modified hydrothermal approach

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Liangliang; Zeng, Yanwei, E-mail: stephen_zeng@njtech.edu.cn; Ding, Chuan; Li, Rongjie; Li, Chuanming; Zhang, Chengzhe

    2016-12-01

    Single phase BaFe{sub 12}O{sub 19} ferrite identified by X-ray diffraction and Raman spectroscopy has been successfully synthesized using Fe(NO{sub 3}){sub 3}·9H{sub 2}O and Ba(NO{sub 3}){sub 2} as starting materials and NaOH as a precipitant via a modified one-step hydrothermal approach which involves the elimination of carbonate radicals from reaction system based on the stoichiometric ratio of [Ba{sup 2+}]/[Fe{sup 3+}]. Hydrothermal products under various synthetic conditions were studied, including different addition amounts of Ba(NO{sub 3}){sub 2} in the modified operation, reaction temperatures and times, and hydroxyl concentrations. The BaFe{sub 12}O{sub 19} particles featuring an excellent hexagonal plates shape can be hydrothermally synthesized with the aid of polyethylene glycol. It has been found that the presence of α-Fe{sub 2}O{sub 3} in a traditional hydrothermal process is motivated by the deviation from the desired [Ba{sup 2+}]/[Fe{sup 3+}] ratio caused by the negligent precipitation of Ba{sup 2+} ions to BaCO{sub 3}. An investigation on the preferred hydrothermal product through thermodynamic calculation shows that the reduction in Gibbs free energy for the exclusive formation of BaFe{sub 12}O{sub 19} with 1 mol of Fe{sup 3+} ions at 220 °C is approximately 32 kJ higher than that for the complete transformation to α-Fe{sub 2}O{sub 3} with an equal consumption quantity of Fe{sup 3+} ions. - Highlights: • Pure BaFe{sub 12}O{sub 19} was hydrothermally synthesized based on the stoichiometric ratio. • A modified operation was employed to eliminate self-invited carbonate ions. • BaFe{sub 12}O{sub 19} particles feature an excellent micro-sized hexaplates shape. • BaFe{sub 12}O{sub 19} was thermodynamically confirmed to be preferred result instead of α-Fe{sub 2}O{sub 3}.

  1. Effect of Cetyl trimethylammonium bromide (CTAB) amount on phase constituents and magnetic properties of nano-sized NiFe{sub 2}O{sub 4} powders synthesized by sol–gel auto-combustion method

    Energy Technology Data Exchange (ETDEWEB)

    Alamolhoda, S., E-mail: alamolhoda@iust.ac.ir; Mirkazemi, S.M.; Shahjooyi, T.; Benvidi, N.

    2015-07-25

    Highlights: • NiFe{sub 2}O{sub 4} was synthesized by sol–gel auto combustion with different CTAB contents. • CTAB addition affects phase constituents and refines the microstructure. • By 3 wt.% of CTAB addition M{sub max} of the synthesized powder reached to 51 emu/g. - Abstract: In this research nano-sized NiFe{sub 2}O{sub 4} powders were synthesized with and without Cetyl trimethylammonium bromide (CTAB) surfactant addition by sol–gel auto-combustion method. Phase constituents, microstructure and magnetic properties as a result of different CTAB addition amounts were evaluated by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscope (FESEM) and vibration sample magnetometer (VSM) techniques. XRD results designated that the combustion product consists of NiFe{sub 2}O{sub 4} as the main phase and some amount of α-Fe{sub 2}O{sub 3} and FeNi{sub 3} phases. Raman spectroscopy represents the formation of NiO phase in addition to the mentioned phases. CTAB addition affects the phase constituents and elimination of α-Fe{sub 2}O{sub 3} residuals from the combustion product while facilitating the formation of FeNi{sub 3} phase. Also its addition leads to powder refinement based on FESEM images. Mean crystallite sizes of the samples by calculated by Scherrer equation showed a decreasing trend from 46 to 27 nm with increasing the amount of CTAB. Magnetic measurements showed that saturation magnetization increased from 36.96 emu/g to 51.07 emu/g by CTAB addition as a result of increased FeNi{sub 3} amount. The intrinsic coercivity values ({sub i}H{sub c}) of the samples are in the range of 164–175 Oe.

  2. Effects of group-size-floor space allowance during the nursery phase of production on growth, physiology, and hematology in replacement gilts.

    Science.gov (United States)

    Callahan, S R; Cross, A J; DeDecker, A E; Lindemann, M D; Estienne, M J

    2017-01-01

    The objective was to determine effects of nursery group-size-floor space allowance on growth, physiology, and hematology of replacement gilts. A 3 × 3 factorial arrangement of treatments was used wherein gilts classified as large, medium, or small ( = 2537; BW = 5.6 ± 0.6 kg) from 13 groups of weaned pigs were placed in pens of 14, 11, or 8 pigs resulting in floor space allowances of 0.15, 0.19, or 0.27 m/pig, respectively. Pigs were weighed on d 0 (weaning) and d 46 (exit from nursery). The ADG was affected by group-size-floor space allowance × pig size ( = 0.04). Large- and medium-size gilts allowed the most floor space had greater ( gilts allowed the least floor space but for small size gilts there was no effect ( > 0.05) of group size-floor space allowance. Mortality in the nursery was not affected ( > 0.05) by treatment, size, or treatment × size and overall was approximately 2.1%. Complete blood counts and blood chemistry analyses were performed on samples collected at d 6 and 43 from a subsample of gilts ( = 18/group-size-floor space allowance) within a single group. The concentration ( gilts allowed 0.15 m floor space (effects of treatment). Blood calcium was affected by treatment ( = 0.02) and concentrations for gilts allowed the greatest and intermediate amounts of floor space were greater ( gilts allowed the least floor space. Serum concentrations of cortisol were not affected by treatment × day ( = 0.27). Cortisol concentrations increased from d 6 to d 43 in all groups and were affected by day ( gilts displaying increased ADG. Further study will determine if these effects influence lifetime reproductive capacity and sow longevity.

  3. Kelly et al. (2016): Simulating the phase partitioning of NH3, HNO3, and HCl with size-resolved particles over northern Colorado in winter

    Data.gov (United States)

    U.S. Environmental Protection Agency — In this study, modeled gas- and aerosol phase ammonia, nitric acid, and hydrogen chloride are compared to measurements taken during a field campaign conducted in...

  4. Influence of external magnetic field, finite-size effects and chemical potential on the phase transition of a complex scalar field

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcanti, E.; Castro, E.; Malbouisson, A.P.C. [Centro Brasileiro de Pesquisas Fisicas/MCTI, Rio de Janeiro, RJ (Brazil); Linhares, C.A. [Universidade do Estado do Rio de Janeiro, Instituto de Fisica, Rio de Janeiro, RJ (Brazil)

    2017-10-15

    A scalar model is built, as a quantum field theory defined on a toroidal topology, to describe a phase transition in films subjected to periodic boundary conditions and influenced by an external and constant magnetic field. Criticality is studied and the relations between the critical temperature, the film thickness, the magnetic field strength and the chemical potential are investigated. Since the model describes a second-order phase transition a comparison with the Ginzburg-Landau theory is made. (orig.)

  5. Measuring Complementary Electronic Structure Properties of both Deposited and Gas Phase Clusters using STM, UPS, and PES: Size-Selected Clusters on Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, Kit H.

    2014-03-05

    In this project, we studied size-selected cluster interactions with surfaces, with other clusters on surfaces, and with external stimuli. These studies focused on mobility as a function of cluster size, surface morphologies as a function of composition and coverage, ion-induced modification and reactivity of clusters as a function of composition, the structural evolution of cluster cuboids culminating in the characterization of theoretically-predicted “baby crystal” clusters, and unusual fractal pattern formation due to deposition.

  6. Tunable diode laser IR spectrometer for in situ measurements of the gas phase composition and particle size distribution of Titan's atmosphere

    Science.gov (United States)

    Webster, Christopher R.; Sander, Stanley P.; Beer, Reinhard; May, Randy D.; Knollenberg, Robert G.

    1990-01-01

    A new instrument, the Probe Infrared Laser Spectrometer (PIRLS), is described for in situ sensing of the gas composition and particle size distribution of Titan's atmosphere on the NASA/ESA Cassini mission. For gas composition measurements, several narrow-band (0.0001/cm) tunable lead-salt diode lasers operating near 80 K at selected mid-IR wavelengths are directed over a path length defined by a small reflector extending over the edge of the probe spacecraft platform; volume mixing ratios of 10 to the -9th should be measurable for several species of interest. A cloud-particle-size spectrometer using a diode laser source at 780 nm shares the optical path and deployed reflector; a combination of imaging and light scattering techniques is used to determine sizes of haze and cloud particles and their number density as a function of altitude.

  7. Grain size tuning of nanostructured Cu{sub 2}O films through vapour phase supersaturation control and their characterization for practical applications

    Energy Technology Data Exchange (ETDEWEB)

    Anu, A.; Abdul Khadar, M., E-mail: mabdulkhadar@rediffmail.com [Centre for Nanoscience and Nanotechnology, University of Kerala, Kariavattom, Thiruvananthapuram - 695 581, Kerala (India)

    2015-09-15

    A strategy for creating nanostructured films is the alignment of nanoparticles into ordered superstructures as living organisms synthesize biomaterials with superior physical properties using nanoparticle building blocks. We synthesized nanostructured films of Cu{sub 2}O of variable grain size by establishing the condition of supersaturation for creation of nanoparticles of copper which deposited as nanograined films and which was then oxidized. This technique has the advantage of being compatible with conventional vacuum processes for electronic device fabrication. The Cu{sub 2}O film samples consisted of a secondary structure of spherical particles of almost uniform size, each particle being an agglomerate of primary nanocrystals. Fractal analysis of the AFM images of the samples is carried out for studying the aggregation mechanism. Grain size tuning of the nanostructured Cu{sub 2}O films has been studied using XRD, and micro-Raman and photoluminescence spectroscopy.

  8. Effects of Physical Size of Clinoptilolite on Growth Performance, Serum Biochemical Parameters and Litter Quality of Broiler Chickens in the Growing Phase

    Directory of Open Access Journals (Sweden)

    Parizadian Kavan B

    2013-08-01

    Full Text Available A total of 448 Ross 308 male broiler chickens were assigned to seven treatments with four replicates, each containing 16 chicks. The birds were reared from d 21 to 42 and effects of physical sizes (ad libitum by a basal commercial broiler diet with 3050 Kcal/Kg ME and 19.06% CP/Kg from 21 to 42 d. The chickens which received clinoptilolite (1.5% with particle size of 0.4-0.8 mm showed a significant increase in body weight gain compared to the control group birds receiving no  clinoptilolite (P

  9. Bound-state energy of the three-dimensional Ising model in the broken-symmetry phase: suppressed finite-size corrections.

    Science.gov (United States)

    Nishiyama, Yoshihiro

    2008-05-01

    The low-lying spectrum of the three-dimensional Ising model is investigated numerically; we made use of an equivalence between the excitation gap and the reciprocal correlation length. In the broken-symmetry phase, the magnetic excitations are attractive, forming a bound state with an excitation gap m_{2} (mass-gap ratio as m_{2}/m_{1}=1.84(3) .

  10. A compact seven switches topology and reduced DC-link capacitor size for single-phase stand-alone PV system with hybrid energy storages

    DEFF Research Database (Denmark)

    Liu, Xiong; Wang, Peng; Loh, Poh Chiang

    2011-01-01

    Single-phase stand-alone PV system is suitable for household applications in remote area. Hybrid battery/ultra-capacitor energy storage can reduce charge and discharge cycles and avoid deep discharges of battery. This paper proposes a compact seven switches structure for stand-alone PV system...... of the topology and control schemes of the proposed system....

  11. NMR studies of organic liquids confined in mesoporous materials: (1) Pore size distribution and (2) Phase behaviour and dynamic studies in restricted geometry

    Energy Technology Data Exchange (ETDEWEB)

    Foerland, Kjersti

    2005-07-01

    In the thesis NMR spectroscopy is used for studying liquids confined in various porous materials. In the first part, pore size distributions of mesoporous silicas and controlled pore glasses were determined by measuring the 1H NMR signal from the non-frozen fraction of the confined liquid as a function of temperature, using benzene, acetonitrile and HMDS as probe molecules. In the second part, the molecular dynamics of acetonitrile, hexamethyldisilane, cyclohexane and cyclopentane confined in mesoporous materials were studied as a function of temperature. 6 papers are included with titles: 1) Pore-size determination of mesoporous materials by 1H NMR spectroscopy. 2) Pore-size distribution in mesoporous materials as studied by 1H NMR. 3) Dynamic 1H and 2H NMR investigations of acetonitrile confined in porous silica. 4) NMR investigations of hexamethyldisilane confined in controlled pore glasses: Pore size distribution and molecular dynamics studies. 5) 1H and 2H NMR studies of cyclohexane nano crystals in controlled pore glasses. 6) 1H NMR relaxation and diffusion studies of cyclohexane and cyclopentane confined in MCM-41.

  12. Particle phase distribution of polycyclic aromatic hydrocarbons in stormwater — Using humic acid and iron nano-sized colloids as test particles

    DEFF Research Database (Denmark)

    Nielsen, Katrine; Kalmykova, Yuliya; Strömvall, Ann-Margret

    2015-01-01

    fraction was found in the sample with occurrence of small nano-sized particles (b10 nm). The results show the importance of developing technologies that both can manage particulate matter and effectively remove PAHs present in the Colloidal and Dissolved fractions in stormwater. © 2015 Elsevier B.V. All......The distribution of polycyclic aromatic hydrocarbons (PAHs) in different particulate fractions in stormwater: Total, Particulate, Filtrated, Colloidal and Dissolved fractions, were examined and compared to synthetic suspensions of humic acid colloids and iron nano-sized particles. The distribution......, surprisingly, high loads were found in the Dissolved fractions. The PAHs identified in stormwater in the Particulate fractions and Dissolved fractions follow their hydrophobic properties. In most samples N50% of the HMW PAHs were found in the Particulate fractions, while the LMW and MMW PAHs were found...

  13. Demonstration of droplet size and vaporization rate measurements in the near field of a two-phase jet with droplet lasing spectroscopy.

    Science.gov (United States)

    Santangelo, P J; Flowers, D; Kennedy, I M

    1998-08-20

    Droplet lasing spectroscopy has been applied to the measurement of droplet size and evaporation rate in a spray. A single droplet, doped with laser dye, was injected along the centerline of a liquid spray. Filters were used to block the strong elastic-scattering signal. The lasing emission from the doped droplet could be detected against the background with mass loadings of liquid in the spray as high as 20%. An analysis of the spectrum of droplet lasing was used to evaluate the droplet diameter. The evaporation rate of the droplet was obtained from consecutive lasing spectra that were obtained from the same droplet. An error analysis of the drop size and drop evaporation measurements was carried out and showed that accurate measurements of evaporation rates were feasible.

  14. How coagulation zone size is underestimated in computer modeling of RF ablation by ignoring the cooling phase just after RF power is switched off.

    Science.gov (United States)

    Irastorza, Ramiro M; Trujillo, Macarena; Berjano, Enrique

    2017-11-01

    All the numerical models developed for radiofrequency ablation so far have ignored the possible effect of the cooling phase (just after radiofrequency power is switched off) on the dimensions of the coagulation zone. Our objective was thus to quantify the differences in the minor radius of the coagulation zone computed by including and ignoring the cooling phase. We built models of RF tumor ablation with 2 needle-like electrodes: a dry electrode (5 mm long and 17G in diameter) with a constant temperature protocol (70°C) and a cooled electrode (30 mm long and 17G in diameter) with a protocol of impedance control. We observed that the computed coagulation zone dimensions were always underestimated when the cooling phase was ignored. The mean values of the differences computed along the electrode axis were always lower than 0.15 mm for the dry electrode and 1.5 mm for the cooled electrode, which implied a value lower than 5% of the minor radius of the coagulation zone (which was 3 mm for the dry electrode and 30 mm for the cooled electrode). The underestimation was found to be dependent on the tissue characteristics: being more marked for higher values of specific heat and blood perfusion and less marked for higher values of thermal conductivity. Copyright © 2017 John Wiley & Sons, Ltd.

  15. Single phase bi-directional AC-DC converter with reduced passive components size and common mode electro-magnetic interference

    Energy Technology Data Exchange (ETDEWEB)

    Mi, Chris; Li, Siqi

    2017-01-31

    A bidirectional AC-DC converter is presented with reduced passive component size and common mode electro-magnetic interference. The converter includes an improved input stage formed by two coupled differential inductors, two coupled common and differential inductors, one differential capacitor and two common mode capacitors. With this input structure, the volume, weight and cost of the input stage can be reduced greatly. Additionally, the input current ripple and common mode electro-magnetic interference can be greatly attenuated, so lower switching frequency can be adopted to achieve higher efficiency.

  16. Kinetic behaviour in supercritical fluid chromatography with modified mobile phase for 5 μm particle size and varied flow rates.

    Science.gov (United States)

    Lesellier, E; Fougere, L; Poe, Donald P

    2011-04-15

    After much development of stationary phase chemistry, in recent years the focus of many studies in HPLC has shifted to increase the efficiency and analysis speed. Ultra high pressure liquid chromatography (UHPLC) using sub-2 μm particles, and high temperature liquid chromatography (HTLC), using temperatures above 100°C have received much attention. These new approaches allow the use of flow rates higher than those classically used in HPLC, reducing the analysis duration. Due to the low viscosity of supercritical fluids, high velocities, i.e. high flow rates, can be achieved with classical pumping systems typically used in supercritical fluid chromatography (SFC). The effects of the flow rate increase with CO(2)/methanol mobile phase was studied on the inlet pressure, t(0), the retention factor of the compounds, and on the efficiency. Simple comparisons of efficiencies obtained at varied temperature between SFC and HPLC, with a packed column containing 5 μm particles, show the greater kinetic performances achieved with the CO(2)/methanol fluid, and underline specific behaviours of SFC, occurring for high flow rates and sub-ambient temperature. Some values (N/t(0)) are also compared to UHPLC data, showing that good performance can be achieved in SFC without applying drastic analytical conditions. Finally, simple kinetic plots (t(0) vs N) at constant column length are used to select combinations of temperature and flow rate necessary to achieve a required theoretical plate number. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Particle phase distribution of polycyclic aromatic hydrocarbons in stormwater--Using humic acid and iron nano-sized colloids as test particles.

    Science.gov (United States)

    Nielsen, Katrine; Kalmykova, Yuliya; Strömvall, Ann-Margret; Baun, Anders; Eriksson, Eva

    2015-11-01

    The distribution of polycyclic aromatic hydrocarbons (PAHs) in different particulate fractions in stormwater: Total, Particulate, Filtrated, Colloidal and Dissolved fractions, were examined and compared to synthetic suspensions of humic acid colloids and iron nano-sized particles. The distribution of low-molecular weight PAHs (LMW PAHs), middle-molecular weight PAHs (MMW PAHs) and high-molecular weight PAHs (HMW PAHs) among the fractions was also evaluated. The results from the synthetic suspensions showed that the highest concentrations of the PAHs were found in the Filtrated fractions and, surprisingly, high loads were found in the Dissolved fractions. The PAHs identified in stormwater in the Particulate fractions and Dissolved fractions follow their hydrophobic properties. In most samples >50% of the HMW PAHs were found in the Particulate fractions, while the LMW and MMW PAHs were found to a higher extent in the Filtrated fractions. The highest concentrations of PAHs were present in the stormwater with the highest total suspended solids (TSS); the relative amount of the HMW PAHs was highest in the Particulate fractions (particles>0.7 μm). The highest concentration of PAHs in the Colloidal fraction was found in the sample with occurrence of small nano-sized particles (importance of developing technologies that both can manage particulate matter and effectively remove PAHs present in the Colloidal and Dissolved fractions in stormwater. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Nano-size confinement effect on phase transition of NaCl and (NH4)2SO4 aqueous droplets reveal the vital role of solution non-ideality

    Science.gov (United States)

    Lei, Ting; Su, Hang; Cheng, Yafang

    2017-04-01

    Understanding the fundamental role of interaction between water molecular and nanoparticles in new-particle formation, particle initial growth by condensation and coagulation, and thereby visibility degradation, cloud formation, radiative forcing is of great significance in the atmospheric researches. But current knowledge about fundamental physical, chemical properties of nanoparticles is still very limited. Here we measured the hygroscopic behavior of atmospheric relevant nanoparticles, such as (NH4)2SO4 and NaCl in the dry size range from 100 nm down to 4-6 nm using a hygroscopic tandem nano-differential mobility analyzer (nano-HTDMA). The diameter growth factors of AS and NaCl decrease with decreasing dry mobility diameter and both show a prompt deliquescence in the range of 100 - 6 nm, which are in a good agreement with Biskos et al. (2006a, 2006b). However, no significant nano-size effect on the deliquescence point of ammonium sulfate observed down to 6 nm, which is consistent with Biskos et al. (2006a). The observed hygroscopic growth of AS and NaCl can be well explained by the concentration dependent water activity and surface tensions retrieved from Differential Köhler analysis (DKA) (Cheng et al. 2015). Our study on the different nano-size confinement effect on phase transition of NaCl and AS aqueous droplets provides further insight on the vital role of the non-ideality of solution properties. references: 1. Biskos, G., et al., Prompt deliquescence and efflorescence of aerosol nanoparticles. Atmospheric Chemistry and Physics, 2006. 6: p. 4633-4642. 2. Biskos, G., et al., Nanosize effect on the hygroscopic growth factor of aerosol particles. Geophysical Research Letters, 2006. 33(7). 3. Cheng, Y., et al., Size dependence of phase transitions in aerosol nanoparticles. Nat Commun, 2015. 6: p. 5923.

  19. Phase transformation kinetics in rolled U-10 wt. % Mo foil: Effect of post-rolling heat treatment and prior γ-UMo grain size

    Energy Technology Data Exchange (ETDEWEB)

    Jana, Saumyadeep; Overman, Nicole; Varga, Tamas; Lavender, Curt; Joshi, Vineet V.

    2017-12-01

    The effect of sub-eutectoid heat treatment on the phase transformation behavior in rolled U-10 wt.percent Mo (U10Mo) foils was systematically investigated. The as-cast 5 mm thick foils were initially homogenized at 900 degrees C for 48 hours and were hot rolled to 2 mm and later cold rolled down to 0.2 mm. Three starting microstructures were evaluated: (i) hot- + cold-rolled to 0.2 mm (as-rolled condition), (ii) hot- + cold-rolled to 0.2 mm + annealed at 700 deg. C for 1 hour, and (iii) hot- + cold-rolled to 0.2 mm + annealed at 1000 deg. C for 60 hours. U10Mo rolled foils went through various degrees of decomposition when subjected to the sub-eutectoid heat-treatment step and formed a lamellar microstructure through a cellular reaction mostly along the previous γ-UMo grain boundaries.

  20. Experimental study on imbibition displacement mechanisms of two-phase fluid using micromodel: Fracture network, distribution of pore size, and matrix construction

    Science.gov (United States)

    Jafari, Iman; Masihi, Mohsen; Nasiri Zarandi, Masoud

    2017-12-01

    In this study, the effect of different parameters on the fluid transport in a fractured micromodel has been investigated. All experiments in this study have been conducted in a glass micromodel. Since the state of wetting is important in the micromodel, the wetting experiments have been conducted to determine the state of wetting in the micromodel. The used micromodel was wet by water and non-wet regarding normal decane. The fracture network, distribution of pore size, matrix construction, and injection rate are the most important parameters affecting the process. Therefore, the influence of these parameters was studied using five different patterns (A to E). The obtained results from pattern A showed that increasing water injection the flow rate results in both higher rate of imbibition and higher ultimate recovery. Pattern B, which was characterized with higher porosity and permeability, was employed to study the effect of matrix pore size distribution on the imbibition process. Compared to pattern A, a higher normal decane production was observed in this pattern. Patterns C and D were designed to understand the impact of lateral fractures on the displacement process. Higher ultimate recoveries were obtained in these patterns. A system of matrix-fracture was designed (pattern E) to evaluate water injection performance in a multi-block system. Injection of water with the flow rate of 0.01 cc/min could produce 15% of the oil available in the system. While in the test with the flow rate of 0.1 cc/min, a normal decane recovery of 0.28 was achieved.

  1. Refinement of a viral transmission risk model for blood donations in seroconversion window phase screened by nucleic acid testing in different pool sizes and repeat test algorithms.

    Science.gov (United States)

    Weusten, Jos; Vermeulen, Marion; van Drimmelen, Harry; Lelie, Nico

    2011-01-01

    In minipool nucleic acid test (MP-NAT) screening protocols, the donations implicated in reactive test pools are released for transfusion when they are nonreactive in a repeat test on the individual samples, but in individual-donation (ID)-NAT screening algorithms the release of nonrepeatable reactive (NRR) donations is under discussion. A previously developed window phase (WP) transmission risk model for NAT-screened blood transfusions has been refined to take the effect of repeat tests of initially reactive (IR) MP- or ID-NAT results into account. The model has then been applied to simulate the effect of different screening algorithms with ULTRIO and the new-generation ULTRIO Plus assay (Novartis Diagnostics) on transmission risk for hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). We calculated WP risk-day equivalents for MP16-, MP8-, and ID-NAT with and without duplicate retesting of IR results of 3.1, 2.7, 1.5, and 1.3 days for HCV; 6.3, 5.5, 3.3, and 2.9 days for HIV; and 24.4, 22.2, 15.6, and 14.1 days for HBV, respectively. These latter infectious HBV WPs reduced to 20.4, 18.2, 11.6, and 10.3 days, respectively, with the more sensitive ULTRIO Plus assay. ULTRIO Plus ID-NAT screening reduces the virus transmission risk in the WP by 54% to 58% compared to ULTRIO MP16-NAT, while the incremental risk caused by releasing donations with duplicate ID-NAT NRR results is 5% to 6%. To achieve maximum safety and specificity a similar repeat test algorithm can be applied to ID-NAT as used for serologic assays. © 2010 American Association of Blood Banks.

  2. The correlation of nitrite concentration with lesion size in initial phase of stroke; It is not correlated with National Institute Health Stroke Scale

    Directory of Open Access Journals (Sweden)

    Mehdi Nematbakhsh

    2008-06-01

    Full Text Available

    • BACKGROUND: The role of Nitric Oxide (NO and its metabolites in stroke has been examined clinically and experimentally. The relationship between plasma NO level and Lesion Size (LS or clinical severity of stroke is still under investigation. In this clinical study, the serum level of Nitrite (NI; the last metabolite of NO was measured in first and fifth days of onset of the stroke, and its correlation with LS was determined.
    • METHOD: 37 Cerebrovascular Attack (CVA patients were considered. The National Institute Health Stroke Scale (NIHSS was assessed to determined neurological impairment within 24 hours of onset. On the basis of NIHSS, the patients were divided into mild, moderate and severe groups. CT Scan for all patients were obtained in the first day, and based on CT Scan results, the patients were also divided into hemorrhagic, ischemic and normal groups. The serum level of NI and the LS were determined.
    • RESULTS: The mean serum levels of NI in 37 patients in the first and fifth days of stroke were 8.43± 1.23 and 7.46±0.72 7mole/liter with no significance difference. The analyses of data indicated no significant correlation between NI concentration and NIHSS, but in patients with abnormal CT Scan, statistical correlation was existed between NI concentration and LS (r=0.521, p=0.022.
    • CONCLUSION: The NI concentration is not correlated with NIHSS, but it is correlated with LS. The sources of NO metabolite sources are different; neuronal, endothelial or inducible. Therefore the concentration of NO or NI is not exactly the endothelial NO reprehensive which is beneficial in stroke, and it seems that the relationship between NO precursor subtypes and NIHSS or LS is needed to investigate.
    • KEYWORDS: Nitric Oxide, Stroke

  3. Size reduction effect on the critical behavior near the paramagnetic to ferromagnetic phase transition temperature in La0.9Sr0.1MnO3 nanoparticles

    Science.gov (United States)

    Baaziz, H.; Tozri, A.; Dhahri, E.; Hlil, E. K.

    2015-04-01

    The critical behavior of La0.9Sr0.1MnO3 nanoparticles, annealed at different temperatures (H6, H8, H10 and H12 annealed at 600 °C, 800 °C, 1000 °C, 1200 °C, respectively), has been investigated by magnetization measurements. Indeed, the magnetic data indicate that the compound exhibits a continuous (second-order) paramagnetic (PM) to ferromagnetic (FM) phase transition. The critical exponents are estimated by various techniques such as the Modified Arrott plot, Kouvel-Fisher plot and critical isotherm technique. Compared to standard models, the critical exponent values determined in our work are close to those expected for the mean-field model (with β=0.5, γ=1, and δ=3) (H8, H10, and H12). Concerning the sample having a smaller crystallite size (H6), the obtained values of the critical exponents β and δ are similar to those predicted by the mean-field model. However, the value of γ shows a (3D) Heisenberg model-like. This behavior, which is quite new and surprising, shows that the reduction of grain size strongly influences the universality class. Moreover, the decrease of the critical exponents (β, γ, δ) with the increase of grain size has been explained by crossover phenomenon. This result and the other obtained values are explained taking into account the contribution of uncompensated spins at the surface, strain anisotropies, and noncollinear magnetic ordering.

  4. Application of colloidal chemistry in aqueous phase to the preparation of supported metallic catalysts: particles size and aggregation control; Application de la chimie colloidale en phase aqueuse a la preparation de catalyseurs metalliques supportes: controle de la taille et de l`etat d`agregation des particules

    Energy Technology Data Exchange (ETDEWEB)

    Pages, T.

    1998-09-16

    This work is an application of colloidal chemistry in aqueous phase on supported metal catalyst preparation. The objective is the control of particle size and aggregation. The preparation of the materials was achieved in two steps: - the synthesis of PdO hydrosols was obtained by two ways: neutralisation of the solution containing metallic salt by adding alkaline solution or by thermo-hydrolysis; the sols were then deposited on carriers (Al{sub 2}O{sub 3}, SIO{sub 2}). The use of partial charge model allowed us to determine the complexes that were able to generate PdO. The preparation of PdO from Pd(H{sub 2}O){sub 4}{sup 2+} was studied and a mechanism of oxide formation was elaborated. The neutralisation of Pd(H{sub 2}O){sub 4}{sup 2+} obtained by adding alkaline solution led to particles with an average size of 1.8 nm and a narrow particle size distribution. Only the thermo-hydrolysis of Pd(H{sub 2}O){sub 4}{sup 2+} led to particles which size is higher than 3.0 nm. In the last case, particle size is controlled by the precursor concentration (Pd(H{sub 2}O){sub 2}(OH){sub 2}) generated in the medium. We have demonstrated that particle aggregation in the sol depends on the Ph and the way of preparation. It can be controlled by adding complexing anions (Cl{sup -}, NO{sub 2}{sup -}). Concerning the deposition of sols on carriers, it led to isolated or aggregated particles according to experimental conditions. Particle size was not modified during the deposition. Moreover, in our experimental conditions, reduction of particles did not modify particle size and aggregation. An application of this original way of preparation on catalysis allowed us to demonstrate the interest of controlling particle size and aggregation. (author) 186 refs.

  5. Effect of pore-size optimization on the performance of polysaccharide-based superficially porous chiral stationary phases for the separation of enantiomers in high-performance liquid chromatography.

    Science.gov (United States)

    Bezhitashvili, Lia; Bardavelidze, Anna; Ordjonikidze, Teona; Chankvetadze, Lali; Chity, Mike; Farkas, Tivadar; Chankvetadze, Bezhan

    2017-01-27

    Our earlier studies on the preparation of chiral stationary phases (CSP) based on superficially porous (or core-shell) silica (SPS) particles for the separation of enantiomers in HPLC have provided proof to the advantages of such sorbents. In particular, higher enantioselectivity was observed with the columns packed with superficially porous CSP compared to the columns packed with fully-porous (FP) silica-based CSPs at comparable content of chiral selector (polysaccharide derivative) in CSP. Also, less dependence of plate height on mobile phase flow rate and higher plate numbers and resolution calculated per unit time (i.e. speed of separation) were observed with SPS-based CSPs. Thirty years of CSP development have demonstrated that wide-pore silica has to be used as a support for large molecular weight chiral selectors such as the ones based on polysaccharides. In this study the effect of pore size of the core-shell silica support and of other experimental factors on column performance is demonstrated. Reduced plate heights in the range 1.4-1.5 were obtained, as well as highly effective baseline separations of enantiomers were observed with analysis times of less than 15s. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Size matter!

    DEFF Research Database (Denmark)

    Hansen, Pelle Guldborg; Jespersen, Andreas Maaløe; Skov, Laurits Rhoden

    2015-01-01

    trash bags according to size of plates and weighed in bulk. Results Those eating from smaller plates (n=145) left significantly less food to waste (aver. 14,8g) than participants eating from standard plates (n=75) (aver. 20g) amounting to a reduction of 25,8%. Conclusions Our field experiment tests...

  7. Rhizosphere size

    Science.gov (United States)

    Kuzyakov, Yakov; Razavi, Bahar

    2017-04-01

    Estimation of the soil volume affected by roots - the rhizosphere - is crucial to assess the effects of plants on properties and processes in soils and dynamics of nutrients, water, microorganisms and soil organic matter. The challenges to assess the rhizosphere size are: 1) the continuum of properties between the root surface and root-free soil, 2) differences in the distributions of various properties (carbon, microorganisms and their activities, various nutrients, enzymes, etc.) along and across the roots, 3) temporal changes of properties and processes. Thus, to describe the rhizosphere size and root effects, a holistic approach is necessary. We collected literature and own data on the rhizosphere gradients of a broad range of physico-chemical and biological properties: pH, CO2, oxygen, redox potential, water uptake, various nutrients (C, N, P, K, Ca, Mg, Mn and Fe), organic compounds (glucose, carboxylic acids, amino acids), activities of enzymes of C, N, P and S cycles. The collected data were obtained based on the destructive approaches (thin layer slicing), rhizotron studies and in situ visualization techniques: optodes, zymography, sensitive gels, 14C and neutron imaging. The root effects were pronounced from less than 0.5 mm (nutrients with slow diffusion) up to more than 50 mm (for gases). However, the most common effects were between 1 - 10 mm. Sharp gradients (e.g. for P, carboxylic acids, enzyme activities) allowed to calculate clear rhizosphere boundaries and so, the soil volume affected by roots. The first analyses were done to assess the effects of soil texture and moisture as well as root system and age on these gradients. The most properties can be described by two curve types: exponential saturation and S curve, each with increasing and decreasing concentration profiles from the root surface. The gradient based distribution functions were calculated and used to extrapolate on the whole soil depending on the root density and rooting intensity. We

  8. Specific determination of selenoaminoacids in whole milk by 2D size-exclusion-ion-paring reversed phase high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP MS)

    Energy Technology Data Exchange (ETDEWEB)

    Bierla, Katarzyna [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, CNRS UMR5254, Helioparc, 2, av. Pr. Angot, 64053 Pau (France)], E-mail: katarzyabierla@wp.pl; Szpunar, Joanna [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, CNRS UMR5254, Helioparc, 2, av. Pr. Angot, 64053 Pau (France); Lobinski, Ryszard [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, CNRS UMR5254, Helioparc, 2, av. Pr. Angot, 64053 Pau (France); Warsaw Technical University, Department of Analytical Chemistry, Noakowskiego 3, 00-664 Warsaw (Poland)

    2008-08-29

    A procedure was developed for the quantitative recovery of selenomethionine (SeMet) and selenocysteine (SeCys) from whole milk. It was based on the protein unfolding, carbamidomethylation of the aminoacid residues using iodoacetamide and proteolysis using Protease XIV. The selenoaminoacids were specifically determined by ion-paring reversed phase HPLC-ICP MS after their isolation from the post-reaction mixture by size-exclusion LC. Se(IV) present in the sample was derivatized as well and was determined along with the selenoaminoacids. The origin and identity of species were identified by the co-elution with the Se(IV), isotopically labelled selenomethionine, and with the synthetic standard of carbamidomethylated selenocysteine. The method development for SeCys was assisted by using glutathione peroxidise as the SeCys standard. SeMet, SeCys and Se(IV) were quantified by the method of standard additions. The mass balance provided a measure of the method validation. The method was applied to monitoring selenium speciation during supplementation of cows (dose-effect study) with Se-rich yeast containing feed and during milk processing.

  9. Specific determination of selenoaminoacids in whole milk by 2D size-exclusion-ion-paring reversed phase high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP MS).

    Science.gov (United States)

    Bierla, Katarzyna; Szpunar, Joanna; Lobinski, Ryszard

    2008-08-29

    A procedure was developed for the quantitative recovery of selenomethionine (SeMet) and selenocysteine (SeCys) from whole milk. It was based on the protein unfolding, carbamidomethylation of the aminoacid residues using iodoacetamide and proteolysis using Protease XIV. The selenoaminoacids were specifically determined by ion-paring reversed phase HPLC-ICP MS after their isolation from the post-reaction mixture by size-exclusion LC. Se(IV) present in the sample was derivatized as well and was determined along with the selenoaminoacids. The origin and identity of species were identified by the co-elution with the Se(IV), isotopically labelled selenomethionine, and with the synthetic standard of carbamidomethylated selenocysteine. The method development for SeCys was assisted by using glutathione peroxidase as the SeCys standard. SeMet, SeCys and Se(IV) were quantified by the method of standard additions. The mass balance provided a measure of the method validation. The method was applied to monitoring selenium speciation during supplementation of cows (dose-effect study) with Se-rich yeast containing feed and during milk processing.

  10. Analysis of Camellia sinensis green and black teas via ultra high performance liquid chromatography assisted by liquid-liquid partition and two-dimensional liquid chromatography (size exclusion × reversed phase).

    Science.gov (United States)

    Scoparo, Camila T; de Souza, Lauro M; Dartora, Nessana; Sassaki, Guilherme L; Gorin, Philip A J; Iacomini, Marcello

    2012-01-27

    Green and black teas (Camellia sinensis) contain compounds ranging from simple phenolics to complex glycosides, many of which have well-recognized health benefits. Here, we describe two methodologies aiming to achieve a comprehensive analysis of hydro-alcoholic extracts of C. sinensis. In the first step, the extracts were partitioned in water, n-butanol, ethyl acetate and chloroform to separate the compounds according to their polarity, yielding less complex samples to be analyzed by ultra high performance liquid chromatography coupled with mass spectrometry (UHPLC-MS). Additionally, a comprehensive two dimensional liquid chromatography (2D-LC) technique, employing size exclusion chromatography (SEC) × reversed phase (BEH-C18) was developed. The following compounds were identified on the basis of retention time, UV-spectra and MS fragmentation patterns: catechins, theaflavins and their gallate derivatives; kaempferol, quercetin and myricetin mono-, di-, tri- and tetraglycosides; esters of quinic acid and gallic or hydroxycinnamic acids; purine alkaloids, such as caffeine and theobromine and many lipids. Additionally, there were many novel compounds that were previously undescribed, such as saponin isomers and gallic acid esters of four glycosides of myricetin, quercetin and kaempferol. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. The dependence of cirrus gamma size distributions expressed as volumes in N0-λ-μ phase space and bulk cloud properties on environmental conditions: Results from the Small Ice Particles in Cirrus Experiment (SPARTICUS)

    Science.gov (United States)

    Jackson, Robert C.; McFarquhar, Greg M.; Fridlind, Ann M.; Atlas, Rachel

    2015-10-01

    The variability of cirrus ice microphysical properties is investigated using observations obtained during the Small Particles in Cirrus (SPARTICUS) campaign. An existing approach that represents a size distribution (SD) as a single gamma function using an ellipsoid of equally realizable solutions in (N0, λ, μ) phase space is modified to automatically identify multiple modes in SDs and characterize each mode by such an ellipsoid. The modified approach is applied to ice crystals with maximum dimension D > 15 µm collected by the 2-D stereo and 2-D precipitation probes on the Stratton Park Engineering Company Learjet. The dependencies of N0, μ, and λ from each mode, total number concentration, bulk extinction, ice water content (IWC), and mass median maximum dimension Dmm as a function of temperature T and cirrus type are then analyzed. The changes in the observed codependencies between N0, μ, and λ, bulk extinction, IWC, and Dmm with environmental conditions indicate that particles were larger at higher T during SPARTICUS. At most two modes were observed in any SD during SPARTICUS, with the average boundary between them at 115 µm, similar to past studies not using probes with shatter mitigating tips and artifact removal algorithms. The bimodality of the SDs increased with T. This and the differences in N0, μ, and λ between the modes suggest that particles with smaller D nucleated more recently than particles with larger D, which grew via vapor deposition and aggregation. Because smaller crystals, whose concentrations are uncertain, make marginal contributions to higher order moments, the use of higher moments for evaluating model fields is suggested.

  12. The Dependence of Cirrus Gamma Size Distributions Expressed as Volumes in N(sub 0)-Lambda-Mu Phase Space and Bulk Cloud Properties on Environmental Conditions: Results from the Small Ice Particles in Cirrus Experiment (SPARTICUS)

    Science.gov (United States)

    Jackson, Robert C.; McFarquhar, Greg M.; Fridlind, Ann M.; Atlas, Rachel

    2015-01-01

    The variability of cirrus ice microphysical properties is investigated using observations obtained during the Small Particles in Cirrus (SPARTICUS) campaign. An existing approach that represents a size distribution (SD) as a single gamma function using an ellipsoid of equally realizable solutions in (N(sub 0), lambda, mu) phase space is modified to automatically identify multiple modes in SDs and characterize each mode by such an ellipsoid. The modified approach is applied to ice crystals with maximum dimension D greater than15 micrometers collected by the 2-D stereo and 2-D precipitation probes on the Stratton Park Engineering Company Learjet. The dependencies of N(sub 0), mu, and lambda from each mode, total number concentration, bulk extinction, ice water content (IWC), and mass median maximum dimension D(sub mm) as a function of temperature T and cirrus type are then analyzed. The changes in the observed codependencies between N(sub 0), mu, and lambda, bulk extinction, IWC, and D(sub mm) with environmental conditions indicate that particles were larger at higher T during SPARTICUS. At most two modes were observed in any SD during SPARTICUS, with the average boundary between them at 115 micrometers, similar to past studies not using probes with shatter mitigating tips and artifact removal algorithms. The bimodality of the SDs increased with T. This and the differences in N(sub 0), mu, and lambda between the modes suggest that particles with smaller D nucleated more recently than particles with larger D, which grew via vapor deposition and aggregation. Because smaller crystals, whose concentrations are uncertain, make marginal contributions to higher order moments, the use of higher moments for evaluating model fields is suggested.

  13. Sonochemical Synthesis of a New Nano Lead(II Coordination Polymer with 2,5-bis(2-pyridyl-3,4-diaza-2,4- hexadiene ligand: A Precursor to Produce Pure Phase Nano- sized Lead(II Oxide

    Directory of Open Access Journals (Sweden)

    A. Morsali

    2011-04-01

    Full Text Available A new nano-sized lead(II coordination polymer, [Pb(2-bpdh(NO32]n (1; (2-bpdh = 2,5-bis(2-pyridyl-3,4-diaza-2,4-hexadiene}, was synthesized by a sonochemical method. The structure of 1 may be considered coordination polymer of lead(II consist of metallocyclicchains formed by bridging NO3- and 2-bpdh ligands. The thermal stability of compound was studied by thermal gravimetric and differential thermal analyses. The new nano-structure coordination polymer was characterized by scanning electron microscopy, powder X-ray diffraction, elemental analyses and IR spectroscopy. The size of the samples was about 50 nm. Nano-particles of PbO were obtained by thermolysis of compound 1in oleic acid as a surfactant at 180 °C under air atmosphere and the size of this PbO particles were about 50 nm.

  14. Phased array observations with infield phasing

    Science.gov (United States)

    Kudale, Sanjay; Chengalur, Jayaram N.

    2017-10-01

    We present results from pulsar observations using the Giant Metrewave Radio Telescope (GMRT) as a phased array with infield phasing. The antennas were kept in phase throughout the observation by applying antenna based phase corrections derived from visibilities that were obtained in parallel with the phased array beam data, and which were flagged and calibrated in real time using a model for the continuum emission in the target field. We find that, as expected, the signal to noise ratio (SNR) does not degrade with time. In contrast observations in which the phasing is done only at the start of the observation show a clear degradation of the SNR with time. We find that this degradation is well fit by a function of the form SNR(τ ) = α + β e^{-(τ /τ 0)^{5/3}}, which corresponds to the case where the phase drifts are caused by Kolmogorov type turbulence in the ionosphere. We also present general formulae (i.e. including the effects of correlated sky noise, imperfect phasing and self noise) for the SNR and synthesized beam size for phased arrays (as well as corresponding formulae for incoherent arrays). These would be useful in planning observations with large array telescopes.

  15. Modeling of liquid phases

    CERN Document Server

    Soustelle, Michel

    2015-01-01

    This book is part of a set of books which offers advanced students successive characterization tool phases, the study of all types of phase (liquid, gas and solid, pure or multi-component), process engineering, chemical and electrochemical equilibria, and the properties of surfaces and phases of small sizes. Macroscopic and microscopic models are in turn covered with a constant correlation between the two scales. Particular attention has been given to the rigor of mathematical developments. This second volume in the set is devoted to the study of liquid phases.

  16. Data collection with a tailored X-ray beam size at 2.69 angstrom wavelength (4.6 keV) : sulfur SAD phasing of Cdc23(Nterm)

    NARCIS (Netherlands)

    Cianci, Michele; Groves, Matthew R.; Barford, David; Schneider, Thomas R.

    The capability to reach wavelengths of up to 3.1 angstrom at the newly established EMBL P13 beamline at PETRA III, the new third-generation synchrotron at DESY in Hamburg, provides the opportunity to explore very long wavelengths to harness the sulfur anomalous signal for phase determination. Data

  17. Cell size, genome size and the dominance of Angiosperms

    Science.gov (United States)

    Simonin, K. A.; Roddy, A. B.

    2016-12-01

    Angiosperms are capable of maintaining the highest rates of photosynthetic gas exchange of all land plants. High rates of photosynthesis depends mechanistically both on efficiently transporting water to the sites of evaporation in the leaf and on regulating the loss of that water to the atmosphere as CO2 diffuses into the leaf. Angiosperm leaves are unique in their ability to sustain high fluxes of liquid and vapor phase water transport due to high vein densities and numerous, small stomata. Despite the ubiquity of studies characterizing the anatomical and physiological adaptations that enable angiosperms to maintain high rates of photosynthesis, the underlying mechanism explaining why they have been able to develop such high leaf vein densities, and such small and abundant stomata, is still incomplete. Here we ask whether the scaling of genome size and cell size places a fundamental constraint on the photosynthetic metabolism of land plants, and whether genome downsizing among the angiosperms directly contributed to their greater potential and realized primary productivity relative to the other major groups of terrestrial plants. Using previously published data we show that a single relationship can predict guard cell size from genome size across the major groups of terrestrial land plants (e.g. angiosperms, conifers, cycads and ferns). Similarly, a strong positive correlation exists between genome size and both stomatal density and vein density that together ultimately constrains maximum potential (gs, max) and operational stomatal conductance (gs, op). Further the difference in the slopes describing the covariation between genome size and both gs, max and gs, op suggests that genome downsizing brings gs, op closer to gs, max. Taken together the data presented here suggests that the smaller genomes of angiosperms allow their final cell sizes to vary more widely and respond more directly to environmental conditions and in doing so bring operational photosynthetic

  18. Size and Political Participation

    DEFF Research Database (Denmark)

    Lassen, David Dreyer; Serritzlew, Søren

    This paper uses a novel research design to re-examine the causal effect of jurisdiction size on political participation. Two waves of municipal consolidation in Denmark, in 1970 and in 2005, provide exogenous variation in jurisdiction size.......This paper uses a novel research design to re-examine the causal effect of jurisdiction size on political participation. Two waves of municipal consolidation in Denmark, in 1970 and in 2005, provide exogenous variation in jurisdiction size....

  19. Bra sizing and fit

    NARCIS (Netherlands)

    Daanen, H.A.M.

    2007-01-01

    It is often reported that 70% or more of the women wear the wrong-sized bra. A fact is that many women complain about bra fit even though the number of available sizes varies from 20 to 100. Sizing of bras is based on under bust circumference and its difference with circumference over the bust (cup

  20. Phase Field

    Science.gov (United States)

    Koyama, Toshiyuki

    The term phase field has recently become known across many fields of materials science. The meaning of phase field is the spatial and temporal order parameter field defined in a continuum-diffused interface model. By using the phase field order parameters, many types of complex microstructure changes observed in materials science are described effectively. This methodology has been referred to as the phase field method, phase field simulation, phase field modeling, phase field approach, etc. In this chapter, the basic concept and theoretical background for the phase field approach is explained in Sects. 21.1 and 21.2. The overview of recent applications of the phase field method is demonstrated in Sects. 21.3 to 21.6.

  1. Use of surfactants to control island size and density

    Science.gov (United States)

    Merrell, Jason; Liu, Feng; Stringfellow, Gerald B.

    2017-08-15

    Methods of controlling island size and density on an OMVPE growth film may comprise adding a surfactant at a critical concentration level, allowing a growth phase for a first period of time, and ending the growth phase when desired island size and density are achieved. For example, the island size and density of an OMVPE grown InGaN thin film may be controlled by adding an antimony surfactant at a critical concentration level.

  2. Sample size for beginners.

    OpenAIRE

    Florey, C D

    1993-01-01

    The common failure to include an estimation of sample size in grant proposals imposes a major handicap on applicants, particularly for those proposing work in any aspect of research in the health services. Members of research committees need evidence that a study is of adequate size for there to be a reasonable chance of a clear answer at the end. A simple illustrated explanation of the concepts in determining sample size should encourage the faint hearted to pay more attention to this increa...

  3. Determination of Sample Size

    OpenAIRE

    Naing, Nyi Nyi

    2003-01-01

    There is a particular importance of determining a basic minimum required ‘n’ size of the sample to recognize a particular measurement of a particular population. This article has highlighted the determination of an appropriate size to estimate population parameters.

  4. Sub-pixel spatial resolution wavefront phase imaging

    Science.gov (United States)

    Stahl, H. Philip (Inventor); Mooney, James T. (Inventor)

    2012-01-01

    A phase imaging method for an optical wavefront acquires a plurality of phase images of the optical wavefront using a phase imager. Each phase image is unique and is shifted with respect to another of the phase images by a known/controlled amount that is less than the size of the phase imager's pixels. The phase images are then combined to generate a single high-spatial resolution phase image of the optical wavefront.

  5. Cell-Size Control.

    Science.gov (United States)

    Amodeo, Amanda A; Skotheim, Jan M

    2016-04-01

    Cells of a given type maintain a characteristic cell size to function efficiently in their ecological or organismal context. They achieve this through the regulation of growth rates or by actively sensing size and coupling this signal to cell division. We focus this review on potential size-sensing mechanisms, including geometric, external cue, and titration mechanisms. Mechanisms that titrate proteins against DNA are of particular interest because they are consistent with the robust correlation of DNA content and cell size. We review the literature, which suggests that titration mechanisms may underlie cell-size sensing in Xenopus embryos, budding yeast, and Escherichia coli, whereas alternative mechanisms may function in fission yeast. Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.

  6. Does size matter?

    Energy Technology Data Exchange (ETDEWEB)

    Carreras, B. A. [BACV Solutions, 110 Mohawk Road, Oak Ridge, Tennessee 37830 (United States); Physics Department, College of Natural Science and Mathematics and Geophysical Institute, University of Alaska, Fairbanks, Alaska 99775 (United States); Physics Department, Universidad Carlos III de Madrid, Madrid (Spain); Newman, D. E., E-mail: denewman@alaska.edu [Physics Department, College of Natural Science and Mathematics and Geophysical Institute, University of Alaska, Fairbanks, Alaska 99775 (United States); Physics Department, Universidad Carlos III de Madrid, Madrid (Spain); Dobson, Ian [ECpE Department, Iowa State University, Ames, Iowa 50011 (United States)

    2014-06-15

    Failures of the complex infrastructures society depends on having enormous human and economic cost that poses the question: Are there ways to optimize these systems to reduce the risks of failure? A dynamic model of one such system, the power transmission grid, is used to investigate the risk from failure as a function of the system size. It is found that there appears to be optimal sizes for such networks where the risk of failure is balanced by the benefit given by the size.

  7. Does size matter?

    Science.gov (United States)

    Carreras, B. A.; Newman, D. E.; Dobson, Ian

    2014-06-01

    Failures of the complex infrastructures society depends on having enormous human and economic cost that poses the question: Are there ways to optimize these systems to reduce the risks of failure? A dynamic model of one such system, the power transmission grid, is used to investigate the risk from failure as a function of the system size. It is found that there appears to be optimal sizes for such networks where the risk of failure is balanced by the benefit given by the size.

  8. Sample size methodology

    CERN Document Server

    Desu, M M

    2012-01-01

    One of the most important problems in designing an experiment or a survey is sample size determination and this book presents the currently available methodology. It includes both random sampling from standard probability distributions and from finite populations. Also discussed is sample size determination for estimating parameters in a Bayesian setting by considering the posterior distribution of the parameter and specifying the necessary requirements. The determination of the sample size is considered for ranking and selection problems as well as for the design of clinical trials. Appropria

  9. Sample size for beginners.

    Science.gov (United States)

    Florey, C D

    1993-05-01

    The common failure to include an estimation of sample size in grant proposals imposes a major handicap on applicants, particularly for those proposing work in any aspect of research in the health services. Members of research committees need evidence that a study is of adequate size for there to be a reasonable chance of a clear answer at the end. A simple illustrated explanation of the concepts in determining sample size should encourage the faint hearted to pay more attention to this increasingly important aspect of grantsmanship.

  10. Genome size evolution: sizing mammalian genomes.

    Science.gov (United States)

    Redi, C A; Capanna, E

    2012-01-01

    The study of genome size (GS) and its variation is so fascinating to the scientific community because it constitutes the link between the present-day analytical and molecular studies of the genome and the old trunk of the holistic and synthetic view of the genome. The GS of several taxa vary over a broad range and do not correlate with the complexity of the organisms (the C-value paradox). However, the biology of transposable elements has let us reach a satisfactory view of the molecular mechanisms that give rise to GS variation and novelties, providing a less perplexing view of the significance of the GS (C-enigma). The knowledge of the composition and structure of a genome is a pre-requisite for trying to understand the evolution of the main genome signature: its size. The radiation of mammals provides an approximately 180-million-year test case for theories of how GS evolves. It has been found from data-mining GS databases that GS is a useful cyto-taxonomical instrument at the level of orders/superorders, providing genomic signatures characterizing Monotremata, Marsupialia, Afrotheria, Xenarthra, Laurasiatheria, and Euarchontoglires. A hypothetical ancestral mammalian-like GS of 2.9-3.7 pg has been suggested. This value appears compatible with the average values calculated for the high systematic levels of the extant Monotremata (∼2.97 pg) and Marsupialia (∼4.07 pg), suggesting invasion of mobile DNA elements concurrently with the separation of the older clades of Afrotheria (∼5.5 pg) and Xenarthra (∼4.5 pg) with larger GS, leaving the Euarchontoglires (∼3.4 pg) and Laurasiatheria (∼2.8 pg) genomes with fewer transposable elements. However, the paucity of GS data (546 mammalian species sized from 5,488 living species) for species, genera, and families calls for caution. Considering that mammalian species may be vanished even before they are known, GS data are sorely needed to phenotype the effects brought about by their variation and to validate any

  11. Does size really matter?

    DEFF Research Database (Denmark)

    Hansen, Maj; Hyland, Philip; Karstoft, Karen-Inge

    2017-01-01

    words, does the size of PTSD really matter? Methods: The aim was investigated by examining differences in diagnostic rates between the two diagnostic systems and independently examining the model fit of the competing DSM-5 and ICD-11 models of PTSD across three trauma samples: university students (N...... diagnostic criteria only the ICD-11 model can reflect the configuration of symptoms satisfactorily. Thus, size does matter when assessing PTSD....

  12. Compressors selection and sizing

    CERN Document Server

    Brown, Royce N

    2005-01-01

    This practical reference provides in-depth information required to understand and properly estimate compressor capabilities and to select the proper designs. Engineers and students will gain a thorough understanding of compression principles, equipment, applications, selection, sizing, installation, and maintenance. The many examples clearly illustrate key aspects to help readers understand the ""real world"" of compressor technology.Compressors: Selection and Sizing, third edition is completely updated with new API standards. Additions requested by readers include a new section on di

  13. Electron microscope phase enhancement

    Science.gov (United States)

    Jin, Jian; Glaeser, Robert M.

    2010-06-15

    A microfabricated electron phase shift element is used for modifying the phase characteristics of an electron beam passing though its center aperture, while not affecting the more divergent portion of an incident beam to selectively provide a ninety-degree phase shift to the unscattered beam in the back focal plan of the objective lens, in order to realize Zernike-type, in-focus phase contrast in an electron microscope. One application of the element is to increase the contrast of an electron microscope for viewing weakly scattering samples while in focus. Typical weakly scattering samples include biological samples such as macromolecules, or perhaps cells. Preliminary experimental images demonstrate that these devices do apply a ninety degree phase shift as expected. Electrostatic calculations have been used to determine that fringing fields in the region of the scattered electron beams will cause a negligible phase shift as long as the ratio of electrode length to the transverse feature-size aperture is about 5:1. Calculations are underway to determine the feasibility of aspect smaller aspect ratios of about 3:1 and about 2:1.

  14. Ethics and sample size.

    Science.gov (United States)

    Bacchetti, Peter; Wolf, Leslie E; Segal, Mark R; McCulloch, Charles E

    2005-01-15

    The belief is widespread that studies are unethical if their sample size is not large enough to ensure adequate power. The authors examine how sample size influences the balance that determines the ethical acceptability of a study: the balance between the burdens that participants accept and the clinical or scientific value that a study can be expected to produce. The average projected burden per participant remains constant as the sample size increases, but the projected study value does not increase as rapidly as the sample size if it is assumed to be proportional to power or inversely proportional to confidence interval width. This implies that the value per participant declines as the sample size increases and that smaller studies therefore have more favorable ratios of projected value to participant burden. The ethical treatment of study participants therefore does not require consideration of whether study power is less than the conventional goal of 80% or 90%. Lower power does not make a study unethical. The analysis addresses only ethical acceptability, not optimality; large studies may be desirable for other than ethical reasons.

  15. Venus Phasing.

    Science.gov (United States)

    Riddle, Bob

    1997-01-01

    Presents a science activity designed to introduce students to the geocentric and heliocentric models of the universe. Helps students discover why phase changes on Venus knocked Earth out of the center of the universe. (DKM)

  16. Size makes a difference

    DEFF Research Database (Denmark)

    Matthiessen, Jeppe; Fagt, Sisse; Biltoft-Jensen, Anja Pia

    2003-01-01

    items was obtained from a 4-day weighed food record (Study 1). Trends in portion sizes of commercial foods were examined by gathering information from major food manufacturers and fast food chains (Study 2). Data on intakes and sales of sugar-sweetened soft drinks and confectionery were obtained through...... increased over time, and in particular in the last 10 years. Study 3: The development in portion sizes of commercial foods has been paralleled by a sharp increase of more than 50% in the sales of sugar-sweetened soft drinks and confectionery like sweets, chocolate and ice creams since the 1970s. Conclusions...

  17. Size and Reputation

    DEFF Research Database (Denmark)

    Jakobsen, Peter Viggo; Ringsmose, Jens

    2015-01-01

    American public gratitude than the UK. While London has been accused of losing Basra and Musa Qaleh, Copenhagen has been showered with praise and top-posts in NATO. This article explains why demonstrating how the differences in size and reputation gave rise to different expectations of the special...

  18. Sizing up visualizations

    DEFF Research Database (Denmark)

    Jakobsen, Mikkel Rønne; Hornbæk, Kasper

    2011-01-01

    techniques with varying display sizes (13.8, 1.5, and 0.17 megapixels). Participants navigated geographical maps to find specific locations, compare items, and follow routes. Results show that for multi-scale navigation, classic interactive visualization techniques did not benefit from being scaled...

  19. Phase coarsening in multicomponent systems.

    Science.gov (United States)

    Wang, K G; Wang, Gabriel Q

    2017-02-01

    A theory for phase coarsening in multicomponent systems is developed in which both the multicomponent thermodynamic effect and kinetic effect from a nonzero volume fraction are considered. In contrast to previous theory, a diffusion screening zone for a coarsening particle due to nonzero volume fraction is introduced. The evolution equation for phase coarsening in multicomponent systems is derived in a rigorous way in the framework of the maximum rate of dissipation with the constraints of mass and energy conservation. Existing previous relations are recovered and generalized. Some findings such as the relationship between the maximum particle size and volume fraction and particle size distribution in multicomponent systems are discovered.

  20. Combustion 2000: Phase II

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    1999-11-01

    The goals of the program are to develop a coal-fired high performance power generation system (HIPPS) that is capable of: thermal efficiency (HHV) {ge} 47%; NOx, SOx, and particulates {le} 10% NSPS (New Source Performance Standard); coal providing {ge} 65% of heat input; all solid wastes benign; and cost of electricity {le} 90% of present plants. Phase 1, which began in 1992, focused on the analysis of various configurations of indirectly fired cycles and on technical assessments of alternative plant subsystems and components, including performance requirements, developmental status, design options, complexity and reliability, and capital and operating costs. Phase 1 also included preliminary R and D and the preparation of designs for HIPPS commercial plants approximately 300 MWe in size. This Phase, Phase 2, had as its initial objective the development of a complete design base for the construction and operation of a HIPPS prototype plant to be constructed in Phase 3. As part of a descoping initiative, the Phase 3 program has been eliminated and work related to the commercial plant design has been ended. The rescoped program retained a program of engineering research and development focusing on high temperature heat exchangers, e.g. HITAF development (Task 2); a rescoped Task 6 that is pertinent to Vision 21 objectives and focuses on advanced cycle analysis and optimization, integration of gas turbines into complex cycles, and repowering designs; and preparation of the Phase 2 Technical Report (Task 8). This rescoped program deleted all subsystem testing (Tasks 3, 4,and 5) and the development of a site-specific engineering design and test plan for the HIPPS prototype plant (Task 7). Work reported herein is from: Task 2.1 HITAF Combustors; Task 2.2 HITAF Air Heaters; and Task 6 HIPPS Commercial Plant Design Update.

  1. Evidence for cubic phase in deposited germanium nanocrystals

    CERN Document Server

    Bostedt, C; Plitzko, J M; Möller, T; Terminello, L J

    2003-01-01

    Germanium nanocrystals with sizes ranging from 1 to 5 nm are condensed out of the gas phase in helium or argon buffer-gas atmospheres and subsequently deposited. The generated particle sizes are found to depend on the buffer gas, with helium yielding a narrower size distribution than argon and argon exhibiting a stronger pressure dependence of the produced particle sizes. Structural analysis of nanoparticles with average sizes around 5 nm reveals the bulklike cubic (diamond) phase - in contrast to recent experiments which suggest the tetragonal phase for similar-sized particles. These results are explained in terms of particle formation dynamics.

  2. Adaptation of Saccades and Perceived Size after Trans-Saccadic Changes of Object Size.

    Science.gov (United States)

    Bosco, Annalisa; Lappe, Markus; Fattori, Patrizia

    2015-10-28

    When saccadic eye movements consistently fail to land on the intended target, saccade accuracy is maintained by gradually adapting the amplitude of successive saccades to the same target. Such saccadic adaptation is usually induced by systematically displacing a small visual target during the execution of the saccade. However, saccades are normally performed to extended objects. Here we report changes in saccade amplitude when the size of a target object is systematically changed during a saccade. Moreover, we find that this manipulation also affected the visual perception of the size of that object. Human subjects were tested in shortening and lengthening adaptation where they had to make saccades to targets of different sizes, which were each shortened or lengthened during saccade execution, respectively. In both experiments, a preadaptation and postadaptation phase required manually indicating the horizontal size of each target by grip aperture and, in a further experiment, a verbal size report. We evaluated the effect of change in visual perception on saccade and on the two modalities of judgment. We observed that (1) saccadic adaptation can be induced by modifying target object size and (2) this gradual change in saccade amplitude in the direction of the object size change evokes a concomitant change in perceived object size. These findings suggest that size is a relevant signal for saccadic system and its trans-saccadic manipulation entails considerable changes at multiple levels of sensorimotor performance. Copyright © 2015 the authors 0270-6474/15/3514448-09$15.00/0.

  3. Integration of Action and Size Perception Through Practice.

    Science.gov (United States)

    Coutte, Alexandre; Camus, Thomas; Heurley, Loïc; Brouillet, Denis

    2017-10-01

    Size perception is known to influence our usual interactions with environment. Numerous studies highlighted that during the visual presentation of an object, the properties of manual actions vary as a function of this object's size. In order to better understand the dynamic variations of relationships between size perception and action, we used an experimental paradigm consisting in two phases. During a previous implicit learning phase, a manual response (right or left) was specifically associated with the appearance of a large or small stimulus. During further test phase, participants were required to prepare a response while discriminating the color of a stimulus (GO/No GO task). We observed that the response execution was faster when the size of the stimulus was congruent with the size that had been associated to this response (during implicit learning phase). These results suggest that when a response usually co-occurs with visual stimuli characterized by a specific size pattern, the response and the size pattern become integrated. Any subsequent preparation and execution of this action are therefore influenced by the reactivation of this visual pattern. This result brings out new insights on how sensorimotor interactions may modulate the ability to anticipate perceptive size variations in the environment.

  4. Nuclear size isomers

    Directory of Open Access Journals (Sweden)

    Ogloblin Alexey

    2016-01-01

    Full Text Available Developing of methods of measuring the radii of nuclei in their highly excited states led to observation of those with dimensions enhanced and, probably, diminished in comparison with the corresponding ground states. Experimental data including very recent ones demonstrating that such “size isomers” belong to two groups: excited states having neutron halos (in 13C, 11Be and 9Be and some specific cluster states (in 12C, 13C and 11B, are discussed.

  5. Group Size and Conformity

    OpenAIRE

    Bond, Rod

    2005-01-01

    Abstract This paper reviews theory and research on the relationship between group size and conformity and presents a meta-analysis of 125 Asch-type conformity studies. It questions the assumption of a single function made in formal models of social influence and proposes instead that the function will vary depending on which social influence process predominates. It is argued that normative influence is lik...

  6. Aerosol mobility size spectrometer

    Science.gov (United States)

    Wang, Jian; Kulkarni, Pramod

    2007-11-20

    A device for measuring aerosol size distribution within a sample containing aerosol particles. The device generally includes a spectrometer housing defining an interior chamber and a camera for recording aerosol size streams exiting the chamber. The housing includes an inlet for introducing a flow medium into the chamber in a flow direction, an aerosol injection port adjacent the inlet for introducing a charged aerosol sample into the chamber, a separation section for applying an electric field to the aerosol sample across the flow direction and an outlet opposite the inlet. In the separation section, the aerosol sample becomes entrained in the flow medium and the aerosol particles within the aerosol sample are separated by size into a plurality of aerosol flow streams under the influence of the electric field. The camera is disposed adjacent the housing outlet for optically detecting a relative position of at least one aerosol flow stream exiting the outlet and for optically detecting the number of aerosol particles within the at least one aerosol flow stream.

  7. Pulse Dispersion in Phased Arrays

    Directory of Open Access Journals (Sweden)

    Randy L. Haupt

    2017-01-01

    Full Text Available Phased array antennas cause pulse dispersion when receiving or transmitting wideband signals, because phase shifting the signals does not align the pulse envelopes from the elements. This paper presents two forms of pulse dispersion that occur in a phased array antenna. The first results from the separation distance between the transmit and receive antennas and impacts the definition of far field in the time domain. The second is a function of beam scanning and array size. Time delay units placed at the element and/or subarrays limit the pulse dispersion.

  8. Phase Vocoder

    Directory of Open Access Journals (Sweden)

    J.L. Flanagan

    2013-08-01

    Full Text Available A vocoder technique is described in which speech signals are represented by their short-time phase and amplitude spectra. A complete transmission system utilizing this approach is simulated on a digital computer. The encoding method leads to an economy in transmission bandwidth and to a means for time compression and expansion of speech signals.

  9. Multimodal Raindrop Size Distributions.

    Science.gov (United States)

    Sauvageot, Henri; Koffi, Manlandon

    2000-08-01

    The raindrop size distributions (DSDs) observed over a short span usually have an erratic shape, with several relative maxima. This multimodal structure is studied from disdrometer data acquired in tropical and midlatitude areas. It is shown that some modes of DSDs have a persistence larger than several minutes and can be spotted from one DSD to the next one as they migrate through the size classes. It is demonstrated that Nm, the number of modes of DSDs, for diameter larger than 2 mm, is not related to the mean rain rate but depends on the rain-rate fluctuations. Statistical evidence of such a relation is given. The spread of DSDs is found to be dependent on its multimodal structure, that is, on Nm. The large values of Nm are associated with low values of slope and intercept N0 of the fitted exponential distribution.In order to explain the dependence of the DSD shape on Nm, a conceptual model is proposed in which the modes are interpreted as resulting from an overlapping of rain shafts. The associated DSD is termed a synthetic drop size distribution (SDSD). It is shown that the overlapping of rain shafts generated from a sequence of rain cells of increasing intensity, such as observed at the leading edge of a convective system, results in undersloping SDSDs. In the reverse configuration, that is, with a sequence of rain cells with decreasing intensity, such as observed at the ending edge of a convective system, it results in oversloping SDSDs. Observations in agreement with these conclusions are presented. The readability of the modal structure of the DSDs depends on several factors in such a way that an apparent multimodal structure is not necessary for a DSD to be an SDSD. It is suggested that most of the DSDs observed at the ground are synthetic DSDs.

  10. Large litter sizes

    DEFF Research Database (Denmark)

    Sandøe, Peter; Rutherford, K.M.D.; Berg, Peer

    2012-01-01

    possible to achieve a drop in relative piglet mortality and the related welfare problems. However, there will be a growing problem with the need to use foster or nurse sows which may have negative effects on both sows and piglets. This gives rise to new challenges for management....... adverse consequences for animal welfare of Danish breeding for large litter sizes due to increased piglet mortality and the subsequent attempts to reverse these consequences by breeding for number of live piglets at day five rather than number of piglets born. By this change of breeding goal it seems...

  11. Phase transformations in metallic glasses

    DEFF Research Database (Denmark)

    Jiang, Jianzhong

    2003-01-01

    Recent development of grain-size effect on phase transformations induced by pressure is reported. A thermodynamic theory is presented and three components: the ratio of volume collapses, the surface energy differences, and the internal energy differences, governing the change of transition pressu...

  12. Cell size control in yeast.

    Science.gov (United States)

    Turner, Jonathan J; Ewald, Jennifer C; Skotheim, Jan M

    2012-05-08

    Cell size is an important adaptive trait that influences nearly all aspects of cellular physiology. Despite extensive characterization of the cell-cycle regulatory network, the molecular mechanisms coupling cell growth to division, and thereby controlling cell size, have remained elusive. Recent work in yeast has reinvigorated the size control field and suggested provocative mechanisms for the distinct functions of setting and sensing cell size. Further examination of size-sensing models based on spatial gradients and molecular titration, coupled with elucidation of the pathways responsible for nutrient-modulated target size, may reveal the fundamental principles of eukaryotic cell size control. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Element parameters for ultrasonic phased arrays

    Science.gov (United States)

    Moles, Michael; Cancre, Fabrice

    2002-05-01

    The industrial use of ultrasonic phased arrays is limited by several factors, such as budget, coverage, beam steering required, as well as the limitations of array manufacture. Only at high frequencies does the minimum array size become a functional limitation. This paper describes the use of phased arrays and the definition of element size, including electronic scanning, beam steering, and Dynamic Depth Focusing. Several examples of industrial applications are given, with the key limiting factor for each described.

  14. phase V

    International Development Research Centre (IDRC) Digital Library (Canada)

    Equinet : réappropriation des ressources aux fins de la santé - phase V. Le Réseau régional pour l'équité en santé en Afrique australe (Equinet) est constitué de professionnels, de chercheurs, de membres de la société civile et de responsables des politiques qui se sont réunis pour promouvoir l'équité en santé et la justice ...

  15. Afterimage size is modulated by size-contrast illusions.

    OpenAIRE

    Sperandio, Irene; Lak, Armin; Goodale, Melvyn

    2012-01-01

    Traditionally, the perceived size of negative afterimages has been examined in relation to E. Emmert's law (1881), a size-distance equation that states that changes in perceived size of an afterimage are a function of the distance of the surface on which it is projected. Here, we present evidence that the size of an afterimage is also modulated by its surrounding context. We employed a new version of the Ebbinghaus-Titchener illusion with flickering surrounding stimuli and a static inner targ...

  16. Asymptotic size determines species abundance in the marine size spectrum

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Beyer, Jan

    2006-01-01

    The majority of higher organisms in the marine environment display indeterminate growth; that is, they continue to grow throughout their life, limited by an asymptotic size. We derive the abundance of species as a function of their asymptotic size. The derivation is based on size-spectrum theory...

  17. Size reduction machine

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, V.

    1999-12-15

    The Size Reduction Machine (SRM) is a mobile platform capable of shearing various shapes and types of metal components at a variety of elevations. This shearing activity can be performed without direct physical movement and placement of the shear head by the operator. The base unit is manually moved and roughly aligned to each cut location. The base contains the electronics: hydraulic pumps, servos, and actuators needed to move the shear-positioning arm. The movable arm allows the shear head to have six axes of movement and to cut to within 4 inches of a wall surface. The unit has a slick electrostatic capture coating to assist in external decontamination. Internal contamination of the unit is controlled by a high-efficiency particulate air (HEPA) filter on the cooling inlet fan. The unit is compact enough to access areas through a 36-inch standard door opening. This paper is an Innovative Technology Summary Report designed to provide potential users with the information they need to quickly determine if a technology would apply to a particular environmental management problem. They also are designed for readers who may recommend that a technology be considered by prospective users.

  18. Variable pixel size ionospheric tomography

    Science.gov (United States)

    Zheng, Dunyong; Zheng, Hongwei; Wang, Yanjun; Nie, Wenfeng; Li, Chaokui; Ao, Minsi; Hu, Wusheng; Zhou, Wei

    2017-06-01

    A novel ionospheric tomography technique based on variable pixel size was developed for the tomographic reconstruction of the ionospheric electron density (IED) distribution. In variable pixel size computerized ionospheric tomography (VPSCIT) model, the IED distribution is parameterized by a decomposition of the lower and upper ionosphere with different pixel sizes. Thus, the lower and upper IED distribution may be very differently determined by the available data. The variable pixel size ionospheric tomography and constant pixel size tomography are similar in most other aspects. There are some differences between two kinds of models with constant and variable pixel size respectively, one is that the segments of GPS signal pay should be assigned to the different kinds of pixel in inversion; the other is smoothness constraint factor need to make the appropriate modified where the pixel change in size. For a real dataset, the variable pixel size method distinguishes different electron density distribution zones better than the constant pixel size method. Furthermore, it can be non-chided that when the effort is spent to identify the regions in a model with best data coverage. The variable pixel size method can not only greatly improve the efficiency of inversion, but also produce IED images with high fidelity which are the same as a used uniform pixel size method. In addition, variable pixel size tomography can reduce the underdetermined problem in an ill-posed inverse problem when the data coverage is irregular or less by adjusting quantitative proportion of pixels with different sizes. In comparison with constant pixel size tomography models, the variable pixel size ionospheric tomography technique achieved relatively good results in a numerical simulation. A careful validation of the reliability and superiority of variable pixel size ionospheric tomography was performed. Finally, according to the results of the statistical analysis and quantitative comparison, the

  19. Origins of Kerr phase and orientational phase in polymer-dispersed liquid crystal

    Science.gov (United States)

    Chang, Chia-Ming; Lin, Yi-Hsin; Reshetnyak, Victor; Park, Chui Ho; Manda, Ramesh; Lee, Seung Hee

    2017-08-01

    The anisotropic properties of nematic liquid crystals result in polarization dependency which leads to requirement of at least a polarizer in liquid crystal photonic devices. To develop polarizer free phase modulation, Kerr effect is one of the path. The phase modulation in polymer dispersed liquid crystals (PDLCs) is shown to have two parts: Kerr phase, which is the optical phase modulation linearly proportional to a square of electric field, and orientational phase. However, many puzzles are still under investigation: the origins of Kerr phase, the relation between Kerr phase and orientational phase, and how two-steps of electro-optical (EO) response relates to Kerr phase and orientational phase. We investigated the origins of Kerr phase and orientational phase in PDLC and their connection to two-step EO response. In our study, the Kerr phase is a result of LC orientation in the center of LC droplets. The orientational phase attribute to orientation of LC molecules near LC-polymer interfaces. The two phase in PDLC samples are adjustable depending on droplet size. We also found that two-steps EO response existing in small droplet (<33 nm) is related to Kerr phase and orientational phase. A modified PDLC model related to the Kerr phase and orientational phase is also proposed. Besides the conventional features of PDLC, such as polarization independent optical phase shift and response time independent of cell gap, we believe the Kerr phase and orientational phase with different response times ( msec) in PDLC pave a way for designing versatile photonic devices with pure optical phase modulation.

  20. Sizing Up the Situation

    Science.gov (United States)

    2004-01-01

    Hailstorm damage to the Space Shuttle's External Tank inspired a NASA innovation with extensive photography applications. In order to measure the defects caused by the storm, Kennedy Space Center used telephoto lenses to zoom in on the tank and view the damage clearly. However, since there was no reference object in the image, the engineers could not determine the scale of the damage. In photographic situations similar to this, an object, such as a ruler, is placed within the field of view. This allows a person to look at a photograph and have a visual indication of the scale of the objects in it. In the External Tank situation, however, this procedure was not possible. As a solution, Kennedy developed the Scaling and Measurement Device for Photographic Images, which provides a non-intrusive means of adding a scale to a photograph. In addition to meeting Kennedy's needs, scaling images is extremely important in crime and accident scene investigations, oil and chemical tank monitoring, and aerial photography. The innovation consists of a tool that attaches directly to a camera or charge coupled device using a standard screw. Two lasers fitted to the device provide parallel beams that are set 1 inch apart. These lasers enable the device to project a pattern into the field of view. When a photograph is taken, the image of the laser pattern appears, along with the image of the object under investigation, allowing the viewer quantifiable information as to the size of the object. The laser beams are accurate to approximately 200 feet. Windows-based software was developed to work with the scaling device tool. The software provides further techniques to measure objects in photographs and digital images. By using the software, any object in the image can be measured diagonally, vertically, and horizontally. The device and its software enable the user to determine two-dimensional measurements within a photograph.

  1. Particle sizes from sectional data

    DEFF Research Database (Denmark)

    Pawlas, Zbynek; Nyengaard, Jens Randel; Jensen, Eva Bjørn Vedel

    2009-01-01

    We propose a new statistical method for obtaining information about particle size distributions from sectional data without specific assumptions about particle shape. The method utilizes recent advances in local stereology. We show how to estimate separately from sectional data the variance due...... to the local stereological estimation procedure and the variance due to the variability of particle sizes in the population. Methods for judging the difference between the distribution of estimated particle sizes and the distribution of true particle sizes are also provided....

  2. Sizing of scramjet vehicles

    Science.gov (United States)

    Ingenito, A.; Gulli, S.; Bruno, C.

    2011-10-01

    The current European project LAPCAT II has the ambitious goal to define a conceptual vehicle capable of achieving the antipodal range Brussels-Sydney (~18,000 km) in about 2 h at Mach number Ma = 8. At this high speed, the requirement of high lift to drag (L/D) ratio is critical to high performance, because of high skin friction and wave drag: in fact, as the Mach number increases, the L/D ratio decreases. The design of the vehicle architecture (shape and propulsion system) is, as a consequence, crucial to achieve a reasonably high L/D. In this work, critical parameters for the preliminary sizing of a hypersonic airbreathing airliner have been identified. In particular, for a given Technology Readiness Level (TRL) and mission requirements, a solution space of possible vehicle architectures at cruise have been obtained. In this work, the Gross Weight at Take-Off (TOGW) was deliberately discarded as a constraint, based on previous studies by Czysz and Vanderkerkhove [1]. Typically, limiting from the beginning, the TOGW leads to a vicious spiral where weight and propulsion system requirements keep growing, eventually denying convergence. In designing passenger airliners, in fact, it is the payload that is assumed fixed from the start, not the total weight. In order to screen the solutions found, requirements for taking-off (TO) and landing as well as the trajectory have been accounted for. A consistent solution has finally been obtained by imposing typical airliner constraints: emergency take-off and landing. These constraints enable singling out a realistic design from the broad family of vehicles capable of performing the given mission. This vehicle has been obtained by integrating not only aerodynamics, trajectory, and airliner constraints, but also by integrating the propulsion system, the trimming devices and by doing some adjustments to the conceptual vehicle shape (i. e., spatular nose). Thus, the final vehicle is the result of many iterations in the design

  3. Broadband phased-arrays antennas

    Science.gov (United States)

    Mansky, L.

    1984-09-01

    The actual jamming-to-signal ratio achieved in an electronic countermeasures (ECM) system depends on the effective radiated power (ERP) directed toward the radar by the ECM system. The required ERP may be obtained in a phase-steered array using a variety of transmit-subsystem hardware configurations. Here, tradeoff criteria to aid in the selection of an optimal architecture are discussed. Such selection is based on minimizing the array size, backscattering cross selection, and overall system complexity. Functional elements of typical phased arrays and their principal components are descried.

  4. Phased Arrays 1985 Symposium - Proceedings

    Science.gov (United States)

    1985-08-01

    diameter to approximately 80-100 mm (3-4 inches) using liquid encapsulated Czochralski growth techniques [22]. Semi- insulating InP wafers are limited...34 \\ .185 , gi vingc the phase shiftr, a size of .240" x .185". Test of the inividual bits ’ro’w Ibreadboard wafers yielded the .elluwinq results. Fniase...collect unevenly at grain boundaries and to produce explosive grain growth . This grain growth may produce rather large macropores of such a size as to be

  5. Bilayer thickness mismatch controls domain size in biomimetic membranes

    Science.gov (United States)

    Heberle, Frederick A.; Petruzielo, Robin S.; Pan, Jianjun; Drazba, Paul; Kučerka, Norbert; Standaert, Robert F.; Feigenson, Gerald W.; Katsara, John

    2013-03-01

    In order to promote functionality, cells may alter the spatial organization of membrane lipids and proteins, including separation of liquid phases into distinct domains. In model membranes, domain size and morphology depend strongly on composition and temperature, but the physicochemical mechanisms controlling them are poorly understood. Theoretical work suggests a role for interfacial energy at domain boundaries, which may be driven in part by thickness mismatch between a domain and its surrounding bilayer. However, no direct evidence linking thickness mismatch to domain size in free-standing bilayers has been reported. We describe the use of Small Angle Neutron Scattering (SANS) to detect domains in simplified lipid-only models that mimic the composition of plasma membrane. We find that domain size is controlled by the degree of acyl chain unsaturation of low-melting temperature lipids, and that this size transition is correlated to changes in the thickness mismatch between coexisting liquid phases.

  6. Size did not matter: An evolutionary account of the variation in penis size and size anxiety

    OpenAIRE

    Menelaos Apostolou

    2016-01-01

    The human penis exhibits considerable variation in size, while a substantial proportion of the adult male population experiences size anxiety. This paper employs an evolutionary framework in order to understand this variation, as well as the concern men exhibit about the adequacy of the size of their penis. It is argued that female choice has been one important sexual selection force, responsible for shaping the size of the penis. However, this force has been relatively weak, because women do...

  7. Effect of particle size in composite materials on radiative properties

    Science.gov (United States)

    Lee, Siu-Chun; White, Susan; Grzesik, Jan

    1993-01-01

    A numerical model for the radiative properties of a composite material composed of ceramic oxide fibers and particles was developed and used to determine the effect of the size parameters of the two components. Results include the computed phase functions for the zirconia and silica composite materials, showing the location and strength of the strong forward-scattering peak. The phase function and the optical properties of the composite are strongly influenced by the particle size parameter through the fiber or particle diameter and the wavelength, the material, and the mixture fraction.

  8. Effect of particle size in composite materials on radiative properties

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Siuchun; White, S.; Grzesik, J. (Applied Sciences Lab., Inc., City of Industry, CA (United States) NASA, Ames Research Center, Moffett Field, CA (United States))

    1993-01-01

    A numerical model for the radiative properties of a composite material composed of ceramic oxide fibers and particles was developed and used to determine the effect of the size parameters of the two components. Results include the computed phase functions for the zirconia and silica composite materials, showing the location and strength of the strong forward-scattering peak. The phase function and the optical properties of the composite are strongly influenced by the particle size parameter through the fiber or particle diameter and the wavelength, the material, and the mixture fraction. 16 refs.

  9. Finite-Size Scaling in Random K-SAT Problems

    Science.gov (United States)

    Ha, Meesoon; Lee, Sang Hoon; Jeon, Chanil; Jeong, Hawoong

    2010-03-01

    We propose a comprehensive view of threshold behaviors in random K-satisfiability (K-SAT) problems, in the context of the finite-size scaling (FSS) concept of nonequilibrium absorbing phase transitions using the average SAT (ASAT) algorithm. In particular, we focus on the value of the FSS exponent to characterize the SAT/UNSAT phase transition, which is still debatable. We also discuss the role of the noise (temperature-like) parameter in stochastic local heuristic search algorithms.

  10. Shape Separation of Colloidal Metal Nanoparticles via Size Exclusion Chromatography

    OpenAIRE

    Marvi, Sarrah

    2016-01-01

    The inherent polydispersity of solution-based, colloidal nanoparticle syntheses has necessitated the development of facile post-processing methods for the purification of anisotropic nanoparticles. Here, the use of size exclusion chromatography is explored for the shape separation of colloidal silver nanocube and colloidal gold bipyramid solutions. Multiple column packing materials, pore sizes, and mobile phases were tested to address the prevalent issues of metal adsorption to the high surfa...

  11. Sauropod dinosaurs evolved moderately sized genomes unrelated to body size.

    Science.gov (United States)

    Organ, Chris L; Brusatte, Stephen L; Stein, Koen

    2009-12-22

    Sauropodomorph dinosaurs include the largest land animals to have ever lived, some reaching up to 10 times the mass of an African elephant. Despite their status defining the upper range for body size in land animals, it remains unknown whether sauropodomorphs evolved larger-sized genomes than non-avian theropods, their sister taxon, or whether a relationship exists between genome size and body size in dinosaurs, two questions critical for understanding broad patterns of genome evolution in dinosaurs. Here we report inferences of genome size for 10 sauropodomorph taxa. The estimates are derived from a Bayesian phylogenetic generalized least squares approach that generates posterior distributions of regression models relating genome size to osteocyte lacunae volume in extant tetrapods. We estimate that the average genome size of sauropodomorphs was 2.02 pg (range of species means: 1.77-2.21 pg), a value in the upper range of extant birds (mean = 1.42 pg, range: 0.97-2.16 pg) and near the average for extant non-avian reptiles (mean = 2.24 pg, range: 1.05-5.44 pg). The results suggest that the variation in size and architecture of genomes in extinct dinosaurs was lower than the variation found in mammals. A substantial difference in genome size separates the two major clades within dinosaurs, Ornithischia (large genomes) and Saurischia (moderate to small genomes). We find no relationship between body size and estimated genome size in extinct dinosaurs, which suggests that neutral forces did not dominate the evolution of genome size in this group.

  12. Fourier phase microscopy with white light.

    Science.gov (United States)

    Bhaduri, Basanta; Tangella, Krishnarao; Popescu, Gabriel

    2013-01-01

    Laser-based Fourier phase microscopy (FPM) works on the principle of decomposition of an image field in two spatial components that can be controllably shifted in phase with respect to each other. However, due to the coherent illumination, the contrast in phase images is degraded by speckles. In this paper we present FPM with spatially coherent white light (wFPM), which offers high spatial phase sensitivity due to the low temporal coherence and high temporal phase stability due to common path geometry. Further, by using a fast spatial light modulator (SLM) and a fast scientific-grade complementary metal oxide semiconductor (sCMOS) camera, we report imaging at a maximum rate of 12.5 quantitative phase frames per second with 5.5 mega pixels image size. We illustrate the utility of wFPM as a contrast enhancement as well as dynamic phase measurement method by imaging section of benign colonic glands and red blood cell membrane fluctuation.

  13. Phase Transformation Dynamics in Porous Battery Electrodes

    CERN Document Server

    Ferguson, Todd R

    2014-01-01

    Porous electrodes composed of multiphase active materials are widely used in Li-ion batteries, but their dynamics are poorly understood. Two-phase models are largely empirical, and no models exist for three or more phases. Using a modified porous electrode theory based on non-equilibrium thermodynamics, we show that experimental phase behavior can be accurately predicted from free energy models, without artificially placing phase boundaries or fitting the open circuit voltage. First, we simulate lithium intercalation in porous iron phosphate, a popular two-phase cathode, and show that the zero-current voltage gap, sloping voltage plateau and under-estimated exchange currents all result from size-dependent nucleation and mosaic instability. Next, we simulate porous graphite, the standard anode with three stable phases, and reproduce experimentally observed fronts of color-changing phase transformations. These results provide a framework for physics-based design and control for electrochemical systems with comp...

  14. Size Matters: Individual Variation in Ectotherm Growth and Asymptotic Size.

    Science.gov (United States)

    King, Richard B; Stanford, Kristin M; Jones, Peter C; Bekker, Kent

    2016-01-01

    Body size, and, by extension, growth has impacts on physiology, survival, attainment of sexual maturity, fecundity, generation time, and population dynamics, especially in ectotherm animals that often exhibit extensive growth following attainment of sexual maturity. Frequently, growth is analyzed at the population level, providing useful population mean growth parameters but ignoring individual variation that is also of ecological and evolutionary significance. Our long-term study of Lake Erie Watersnakes, Nerodia sipedon insularum, provides data sufficient for a detailed analysis of population and individual growth. We describe population mean growth separately for males and females based on size of known age individuals (847 captures of 769 males, 748 captures of 684 females) and annual growth increments of individuals of unknown age (1,152 males, 730 females). We characterize individual variation in asymptotic size based on repeated measurements of 69 males and 71 females that were each captured in five to nine different years. The most striking result of our analyses is that asymptotic size varies dramatically among individuals, ranging from 631-820 mm snout-vent length in males and from 835-1125 mm in females. Because female fecundity increases with increasing body size, we explore the impact of individual variation in asymptotic size on lifetime reproductive success using a range of realistic estimates of annual survival. When all females commence reproduction at the same age, lifetime reproductive success is greatest for females with greater asymptotic size regardless of annual survival. But when reproduction is delayed in females with greater asymptotic size, lifetime reproductive success is greatest for females with lower asymptotic size when annual survival is low. Possible causes of individual variation in asymptotic size, including individual- and cohort-specific variation in size at birth and early growth, warrant further investigation.

  15. Size Matters: Individual Variation in Ectotherm Growth and Asymptotic Size

    Science.gov (United States)

    King, Richard B.

    2016-01-01

    Body size, and, by extension, growth has impacts on physiology, survival, attainment of sexual maturity, fecundity, generation time, and population dynamics, especially in ectotherm animals that often exhibit extensive growth following attainment of sexual maturity. Frequently, growth is analyzed at the population level, providing useful population mean growth parameters but ignoring individual variation that is also of ecological and evolutionary significance. Our long-term study of Lake Erie Watersnakes, Nerodia sipedon insularum, provides data sufficient for a detailed analysis of population and individual growth. We describe population mean growth separately for males and females based on size of known age individuals (847 captures of 769 males, 748 captures of 684 females) and annual growth increments of individuals of unknown age (1,152 males, 730 females). We characterize individual variation in asymptotic size based on repeated measurements of 69 males and 71 females that were each captured in five to nine different years. The most striking result of our analyses is that asymptotic size varies dramatically among individuals, ranging from 631–820 mm snout-vent length in males and from 835–1125 mm in females. Because female fecundity increases with increasing body size, we explore the impact of individual variation in asymptotic size on lifetime reproductive success using a range of realistic estimates of annual survival. When all females commence reproduction at the same age, lifetime reproductive success is greatest for females with greater asymptotic size regardless of annual survival. But when reproduction is delayed in females with greater asymptotic size, lifetime reproductive success is greatest for females with lower asymptotic size when annual survival is low. Possible causes of individual variation in asymptotic size, including individual- and cohort-specific variation in size at birth and early growth, warrant further investigation. PMID

  16. Nucleation of Ordered Phases in Block Copolymers

    Science.gov (United States)

    Cheng, Xiuyuan; Lin, Ling; E, Weinan; Zhang, Pingwen; Shi, An-Chang

    2010-04-01

    Nucleation of various ordered phases in block copolymers is studied by examining the free-energy landscape within the self-consistent field theory. The minimum energy path (MEP) connecting two ordered phases is computed using a recently developed string method. The shape, size, and free-energy barrier of critical nuclei are obtained from the MEP, providing information about the emergence of a stable ordered phase from a metastable phase. In particular, structural evolution of embryonic gyroid nucleus is predicted to follow two possible MEPs, revealing an interesting transition pathway with an intermediate perforated layered structure.

  17. Strain Partitioning and Load Transfer in Constituent Phases in Dual-Phase Steels

    Science.gov (United States)

    Varshney, A.; Sangal, S.; Mondal, K.

    2016-09-01

    In this investigation, a new approach is proposed to calculate in situ true stress and strain in the constituent phases of dual-phase steel during deformation. The model incorporates modified law of mixture and constitutive equations. The model proposes that the deformation of martensite is pseudoelastic, and on little permanent deformation within the martensite allows the locked-in dislocation to release in the ferrite at the interface region of the ferrite and martensite. On application of the model to a set of dual-phase steels with varying microstructural parameters, it is established that the amount of strain partitioning is affected by the strength and amount of the hard phase, as well as grain size, work hardening ability, and yield strength of the softer phase. On the other hand, grain size, carbon content, and fraction and strength of martensite are the main factors controlling the load transfer among the phases.

  18. On the Relationship between Pollen Size and Genome Size

    Directory of Open Access Journals (Sweden)

    Charles A. Knight

    2010-01-01

    Full Text Available Here we test whether genome size is a predictor of pollen size. If it were, inferences of ancient genome size would be possible using the abundant paleo-palynolgical record. We performed regression analyses across 464 species of pollen width and genome size. We found a significant positive trend. However, regression analysis using phylogentically independent contrasts did not support the correlated evolution of these traits. Instead, a large split between angiosperms and gymnosperms for both pollen width and genome size was revealed. Sister taxa were not more likely to show a positive contrast when compared to deeper nodes. However, significantly more congeneric species had a positive trend than expected by chance. These results may reflect the strong selection pressure for pollen to be small. Also, because pollen grains are not metabolically active when measured, their biology is different than other cells which have been shown to be strongly related to genome size, such as guard cells. Our findings contrast with previously published research. It was our hope that pollen size could be used as a proxy for inferring the genome size of ancient species. However, our results suggest pollen is not a good candidate for such endeavors.

  19. Parameterizing Size Distribution in Ice Clouds

    Energy Technology Data Exchange (ETDEWEB)

    DeSlover, Daniel; Mitchell, David L.

    2009-09-25

    PARAMETERIZING SIZE DISTRIBUTIONS IN ICE CLOUDS David L. Mitchell and Daniel H. DeSlover ABSTRACT An outstanding problem that contributes considerable uncertainty to Global Climate Model (GCM) predictions of future climate is the characterization of ice particle sizes in cirrus clouds. Recent parameterizations of ice cloud effective diameter differ by a factor of three, which, for overcast conditions, often translate to changes in outgoing longwave radiation (OLR) of 55 W m-2 or more. Much of this uncertainty in cirrus particle sizes is related to the problem of ice particle shattering during in situ sampling of the ice particle size distribution (PSD). Ice particles often shatter into many smaller ice fragments upon collision with the rim of the probe inlet tube. These small ice artifacts are counted as real ice crystals, resulting in anomalously high concentrations of small ice crystals (D < 100 µm) and underestimates of the mean and effective size of the PSD. Half of the cirrus cloud optical depth calculated from these in situ measurements can be due to this shattering phenomenon. Another challenge is the determination of ice and liquid water amounts in mixed phase clouds. Mixed phase clouds in the Arctic contain mostly liquid water, and the presence of ice is important for determining their lifecycle. Colder high clouds between -20 and -36 oC may also be mixed phase but in this case their condensate is mostly ice with low levels of liquid water. Rather than affecting their lifecycle, the presence of liquid dramatically affects the cloud optical properties, which affects cloud-climate feedback processes in GCMs. This project has made advancements in solving both of these problems. Regarding the first problem, PSD in ice clouds are uncertain due to the inability to reliably measure the concentrations of the smallest crystals (D < 100 µm), known as the “small mode”. Rather than using in situ probe measurements aboard aircraft, we employed a treatment of ice

  20. Study of the use of personal equipment in low coal. Experiments on personal equipment for low seam coal miners: II. Effect of size and weight of battery pack on performance. Phase II report, number 3. Open file report 1 Jan 79-1 Sep 79

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, M.; Krohn, G.; Wick, D.; Volkmer, K.; Beith, B.

    1980-01-31

    The objective of this study was to determine optimal personal equipment design for use in low coal based on ergonomic, biomechanic, and safety considerations. This report describes three experiments that were conducted to determine the effects of size and weight of battery packs. The first experiment tested the sensitivity of task measures; that is, workers performed locomotion, shoveling, cart pushing, and timbering tasks to detect variations in the size and weight of battery packs. The second experiment focused on locomotion tasks and tested the effects of varying size and weight on task completion time. The third experiment compared the battery pack presently in use with a radically different configuration of power cells.

  1. Experimental Analysis of Reduced-Sized Coplanar Waveguide Transmission Lines

    Science.gov (United States)

    Ponchak, George E.

    2002-01-01

    An experimental investigation of the use of capacitive loading of coplanar waveguides to reduce their line length and, thus the size, of monolithic microwave integrated circuits is presented. The reduced sized coplanar waveguides are compared to unloaded transmission lines and to lumped element transmission line segments. The phase bandwidth, defined by 2 percent error in S(sub 21), and the return loss bandwidth, defined by a return loss greater than 15 dB, of coplanar waveguides reduced from 0 to 90 percent are compared, and the insertion loss as a function of the size reduction is presented.

  2. Phase Behavior of Laundry Surfactants in Polar Solvents

    NARCIS (Netherlands)

    Stuart, Marc C.A.; Pas, John C. van de; Engberts, Jan B.F.N.

    2006-01-01

    Laundry surfactants are usually mixtures of ionic and nonionic detergents that exhibit a complex phase behavior. Here the ternary phase behavior of an isotropic and a liquid crystalline (LC) surfactant mixture has been examined in water/solvent systems. The size of the LC area in the ternary phase

  3. Size did not matter: An evolutionary account of the variation in penis size and size anxiety

    Directory of Open Access Journals (Sweden)

    Menelaos Apostolou

    2016-12-01

    Full Text Available The human penis exhibits considerable variation in size, while a substantial proportion of the adult male population experiences size anxiety. This paper employs an evolutionary framework in order to understand this variation, as well as the concern men exhibit about the adequacy of the size of their penis. It is argued that female choice has been one important sexual selection force, responsible for shaping the size of the penis. However, this force has been relatively weak, because women do not consider the size of their partners’ penis to be the most important determinant of their sexual satisfaction. Also, in ancestral human societies, sexual satisfaction was a secondary concern, while women had limited space to exercise mate choice. The mismatch between ancestral and modern conditions, with female choice being stronger in the present than in the past, causes anxiety in men about their ability to satisfy their partners, which is also manifested in their concerns about size.

  4. Size Effects in PbTiO3 nanocrystals: Effect of Particle Size on Spontaneous Polarization and Strains

    Energy Technology Data Exchange (ETDEWEB)

    Akdgan,E.; Rawn, C.; Porter, W.; Payzant, E.; Safari, A.

    2005-01-01

    The spontaneous polarization (P{sub s}) and spontaneous strains (x{sub i}) in mechanically unclamped and surface charge compensated PbTiO{sub 3} nanocrystals were determined as a function of particle size in the range <150 nm by differential scanning calorimetry and x-ray powder diffraction, respectively. Significant deviations from bulk order parameters (P, x{sub i}) have been observed as the particle size decreased below {approx}100 nm. The critical size (r{sub c}) below which the ferroelectric tetragonal phase transforms to the paraelectric cubic phase was determined as {approx}15 nm. The depression in transition temperature with particle size is 14 C at 28 nm. No change in the order of m3m-->4mm ferrodistortive phase transition is observed. A simple analysis showed that {Delta}Htr/(kBT){approx}10{sup 3} at 25 C for r=16 nm, indicating that the stabilization of the cubic phase at rc cannot be linked to an instability in dipolar ordering due to thermal agitations. Comparison of the spontaneous volumetric strains with the strain induced by surface stress indicated that the effect of surface stress on ferroelectric phase stability was negligible. Anomalies in electrostrictive properties were determined for r{yields}r{sub c}. The observed size dependence of P{sub S} is attributed to the reduced extent of long-range dipole-dipole interactions that arise due to the changes in bonding characteristics of ions with decreasing particle size in the perovskite lattice, in conformity with a recent study by Tsunekawa et al.

  5. Size effects in PbTiO3 nanocrystals: Effect of particle size on spontaneous polarization and strains

    Science.gov (United States)

    Akdogan, E. K.; Rawn, C. J.; Porter, W. D.; Payzant, E. A.; Safari, A.

    2005-04-01

    The spontaneous polarization (Ps) and spontaneous strains (xi) in mechanically unclamped and surface charge compensated PbTiO3 nanocrystals were determined as a function of particle size in the range <150nm by differential scanning calorimetry and x-ray powder diffraction, respectively. Significant deviations from bulk order parameters (P,xi) have been observed as the particle size decreased below ˜100nm. The critical size (rc) below which the ferroelectric tetragonal phase transforms to the paraelectric cubic phase was determined as ˜15nm. The depression in transition temperature with particle size is 14 °C at 28 nm. No change in the order of m3m →4mm ferrodistortive phase transition is observed. A simple analysis showed that ΔHtr/(kBT )˜103 at 25 °C for r =16nm, indicating that the stabilization of the cubic phase at rc cannot be linked to an instability in dipolar ordering due to thermal agitations. Comparison of the spontaneous volumetric strains with the strain induced by surface stress indicated that the effect of surface stress on ferroelectric phase stability was negligible. Anomalies in electrostrictive properties were determined for r →rc. The observed size dependence of PS is attributed to the reduced extent of long-range dipole-dipole interactions that arise due to the changes in bonding characteristics of ions with decreasing particle size in the perovskite lattice, in conformity with a recent study by Tsunekawa et al. [Phys. Rev. Lett. 85 (16), 4340 (2000)].

  6. Modeling particle size distributions by the Weibull distribution function

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Zhigang (Rogers Tool Works, Rogers, AR (United States)); Patterson, B.R.; Turner, M.E. Jr (Univ. of Alabama, Birmingham, AL (United States))

    1993-10-01

    A method is proposed for modeling two- and three-dimensional particle size distributions using the Weibull distribution function. Experimental results show that, for tungsten particles in liquid phase sintered W-14Ni-6Fe, the experimental cumulative section size distributions were well fit by the Weibull probability function, which can also be used to compute the corresponding relative frequency distributions. Modeling the two-dimensional section size distributions facilitates the use of the Saltykov or other methods for unfolding three-dimensional (3-D) size distributions with minimal irregularities. Fitting the unfolded cumulative 3-D particle size distribution with the Weibull function enables computation of the statistical distribution parameters from the parameters of the fit Weibull function.

  7. Phase contrast image synthesis

    DEFF Research Database (Denmark)

    Glückstad, J.

    1996-01-01

    A new method is presented for synthesizing arbitrary intensity patterns based on phase contrast imaging. The concept is grounded on an extension of the Zernike phase contrast method into the domain of full range [0; 2 pi] phase modulation. By controlling the average value of the input phase...... function and by choosing appropriate phase retardation at the phase contrast filter, a pure phase to intensity imaging is accomplished. The method presented is also directly applicable in dark field image synthesis....

  8. Bubble size distribution of foam

    NARCIS (Netherlands)

    den Engelsen, C.W.; den Engelsen, C.W.; Isarin, J.C.; Warmoeskerken, Marinus; Groot Wassink, J.; Groot Wassink, J.

    2002-01-01

    A procedure based upon image analysis has been adopted to study the influence of several physical parameters on bubble size in foam. A procedure has been described to account for the distribution of bubble size. Foam was generated in a rotor-stator mixer. In the present research, the nature of the

  9. Population Density and Group Size

    Science.gov (United States)

    Tucker, James; Friedman, S. Thomas

    1972-01-01

    This study looks at the relationship between the size of the small interacting group (in numbers of persons) and its environment; in this case, the density of its immediate population. Results indicated a significant inverse relationship between population density and the size of small interacting groups. (Author)

  10. Measuring the Sizes of Stars

    Indian Academy of Sciences (India)

    Stars, other than the Sun, appear to our unaided eyes aspoints of light. Large telescopes show an image whose sizeis dictated by refractive index irregularities in the Earth's atmosphere.The size of this blurring is much greater than thatof the star, and hence it is difficult to measure the stellar size.Fizeau showed how one ...

  11. The importance of effect sizes

    NARCIS (Netherlands)

    B. Winkens; Dr. Sil Aarts; M. van den Akker

    2013-01-01

    KEY MESSAGE: •  Statistical significance testing alone is not the most adequate manner to evaluate if there is indeed a clinically relevant effect •  Effect sizes should be added to significance testing •  Effect sizes facilitate the decision whether a clinically relevant effect is found, helps

  12. Firm Size and Export Intensity

    NARCIS (Netherlands)

    E. Verwaal (Ernst); A.C.D. Donkers (Bas)

    2001-01-01

    textabstractThis paper presents a unifying theory, explaining the different relationships between firm size and export intensity that have been found in previous studies. We propose that transaction costs economies and different types of resources induce a moderating effect on the firm size and

  13. Sibship Size and Educational Attainment

    DEFF Research Database (Denmark)

    Jæger, Mads Meier

    2009-01-01

    Studies on family background often explain the negative effect of sibship size on educational attainment by one of two theories: the Confluence Model (CM) or the Resource Dilution Hypothesis (RDH). However, as both theories - for substantively different reasons - predict that sibship size should ...

  14. Life cycle size dynamics in Didymosphenia geminata (Bacillariophyceae).

    Science.gov (United States)

    Bishop, Ian W; Spaulding, Sarah A

    2017-06-01

    Didymosphenia geminata has received a great deal of attention in the last 25 years, and considerable effort has gone into determining the origin, ecological impact, and economic consequences of its invasive behavior. While environmental conditions are a controlling influence in distribution, the extreme success of the species may be tied to its basic biology and life history. Little is known, however, about population dynamics, size restoration and reproduction of D. geminata. The objective of this study was to determine the temporal patterns in cell size frequency, size restoration strategy, and synchronization of life cycles between populations in close proximity. We implemented FlowCam technology to measure the length of more than 100,000 D. geminata cells from two sites in South Boulder Creek, Colorado over 1 year. We applied finite mixture modeling to uncover temporal patterns in size distribution. Our results show that collections of D. geminata exhibited a complex, multimodal size distribution, almost always containing four overlapping age cohorts. We failed to observe direct visual evidence of the sexual phase. Multiple abrupt and directional shifts in size distribution, however, were documented providing conclusive evidence of cell size restoration. Lastly, nodules in close proximity were asynchronous with respect to size frequency profiles and size diminution, highlighting the relevance of spatial heterogeneity in in situ diatom size dynamics. This study is the first to document the complexity of diatom cell size distribution in a lotic system, size restoration in D. geminata, and the variability in rates of size reduction at microhabitat spatial scales. © 2017 Phycological Society of America.

  15. Food aroma affects bite size

    Directory of Open Access Journals (Sweden)

    de Wijk René A

    2012-03-01

    Full Text Available Abstract Background To evaluate the effect of food aroma on bite size, a semisolid vanilla custard dessert was delivered repeatedly into the mouth of test subjects using a pump while various concentrations of cream aroma were presented retronasally to the nose. Termination of the pump, which determined bite size, was controlled by the subject via a push button. Over 30 trials with 10 subjects, the custard was presented randomly either without an aroma, or with aromas presented below or near the detection threshold. Results Results for ten subjects (four females and six males, aged between 26 and 50 years, indicated that aroma intensity affected the size of the corresponding bite as well as that of subsequent bites. Higher aroma intensities resulted in significantly smaller sizes. Conclusions These results suggest that bite size control during eating is a highly dynamic process affected by the sensations experienced during the current and previous bites.

  16. Missing portion sizes in FFQ

    DEFF Research Database (Denmark)

    Køster-Rasmussen, Rasmus; Siersma, Volkert Dirk; Halldorson, Thorhallur I.

    2015-01-01

    of portion sizes based on information about anthropometry, sex, physical activity and age. Energy intakes computed with standard portion sizes, defined as sex-specific medians (median), or with portion sizes estimated with multinomial logistic regression (MLR), ‘comparable categories’ (Coca) or k...... with the reference, the root-mean-square errors of the mean daily total energy intake (in kJ) computed with portion sizes estimated by the four methods were (men; women): median (1118; 1061), MLR (1060; 1051), Coca (1230; 1146), KNN (1281; 1181). The equivalent biases (mean error) were (in kJ): median (579; 469......), MLR (248; 178), Coca (234; 188), KNN (−340; 218). Conclusions: The methods MLR and Coca provided the best agreement with the reference. The stochastic methods allowed for estimation of meaningful portion sizes by conditioning on information about physiology and they were suitable for multiple...

  17. Cell Size Regulation in Bacteria

    Science.gov (United States)

    Amir, Ariel

    2014-05-01

    Various bacteria such as the canonical gram negative Escherichia coli or the well-studied gram positive Bacillus subtilis divide symmetrically after they approximately double their volume. Their size at division is not constant, but is typically distributed over a narrow range. Here, we propose an analytically tractable model for cell size control, and calculate the cell size and interdivision time distributions, as well as the correlations between these variables. We suggest ways of extracting the model parameters from experimental data, and show that existing data for E. coli supports partial size control, and a particular explanation: a cell attempts to add a constant volume from the time of initiation of DNA replication to the next initiation event. This hypothesis accounts for the experimentally observed correlations between mother and daughter cells as well as the exponential dependence of size on growth rate.

  18. Purification of bacteriocins using size-exclusion chromatography

    Directory of Open Access Journals (Sweden)

    Vivek K. Bajpai

    2016-06-01

    Full Text Available The bacteriocin purification involves following main steps. a. Extraction of cell-free-supernatant of bacteria. b. Ammonium sulfate precipitation. c. Dialysis. d. Diafiltration using PVP and e. Size-exclusion chromatography. However, depending on the nature of work, the compound could be further analyzed by reverse-phase HPLC, NMR, mass spectrometry and sequencing.

  19. Flow regimes of inertial suspensions of finite size particles

    NARCIS (Netherlands)

    Lashgari, I.; Picano, F.; Breugem, W.P.; Brandt, L.

    2015-01-01

    Inertial regimes in a channel flow of suspension of finite-size neutrally buoyant particles are studied for a wide range of Reynolds numbers: 500 Re 5000, and particle volume fractions: 0 0:3. The flow is classified in three different regimes according to the phase-averaged stress budget across the

  20. Particle size effects in colloidal gelatin particle suspensions

    NARCIS (Netherlands)

    Riemsdijk, van L.E.; Snoeren, J.P.M.; Goot, van der A.J.; Boom, R.M.; Hamer, R.J.

    2010-01-01

    This paper describes the effects of simple shear flow on the formation and properties of colloidal gelatin particle suspensions. Microscopy and light scattering show that simple shear flow of a phase-separating gelatin–dextran mixture gave smaller particles with a narrower size distribution. Upon

  1. Phased arrays '85

    Science.gov (United States)

    Stiglitz, M. R.

    1985-11-01

    The conference Phased Arrays '85 was held in Bedford, MA, on October 15-18, 1985. It is pointed out that the 15 years between the 1970 and 1985 conferences dedicated to phased array antennas have seen many technological advances. Attention is given to the principle of operation, monolithic phased arrays, active arrays of monopole elements, scan compensated active element patterns, microstrip arrays, time delay technologies for phased array systems, ferrite materials for mm-wave phase shifters, phase-only optimization of phased array excitation by B-quadratic programming, a nearly frequency-independent sidelobe suppression technique for phased arrays, and active impedance effects in low sidelobe and ultrawideband phased arrays.

  2. Metastable phases and 'metastable' phase diagrams

    Science.gov (United States)

    Brazhkin, V. V.

    2006-10-01

    The work discusses the qualitative nature of phase transitions for metastable states of substances. The objects of the physics of condensed media are primarily the equilibrium states of substances with metastable phases viewed as an exception, while in chemistry the overwhelming majority of organic substances under investigation are metastable. It turns out that at normal pressure many simple molecular compounds based on light elements (these include: most hydrocarbons; nitrogen oxides, hydrates, and carbides; carbon oxide (CO); alcohols, glycerin) are metastable substances too, i.e. they do not match the Gibbs free energy minimum for a given atomic chemical composition. At moderate temperatures and pressures, the phase transitions for particular metastable phases are reversible throughout the entire experimentally accessible time period with the equilibrium thermodynamics laws obeyed. At sufficiently high pressures (1-10 GPa), most molecular phases irreversibly transform to more energy efficient polymerized phases. These transformations are not consistent with the equality of the Gibbs free energies between the phases before and after transition, i.e. they are not phase transitions in the 'classical' meaning. The resulting polymeric phases at normal pressure can exist at temperatures above the melting one for an initial metastable molecular phase. Striking examples of such polymers are polyethylene and a polymerized modification of CO. Many energy-intermediate polymeric phases can apparently be synthesized by the 'classical' chemistry techniques at normal pressure. At higher pressures (10-100 GPa) polymerized modifications transform to a mixture of simple stable phases.

  3. Biological motion distorts size perception

    Science.gov (United States)

    Veto, Peter; Einhäuser, Wolfgang; Troje, Nikolaus F.

    2017-02-01

    Visual illusions explore the limits of sensory processing and provide an ideal testbed to study perception. Size illusions - stimuli whose size is consistently misperceived - do not only result from sensory cues, but can also be induced by cognitive factors, such as social status. Here we investigate, whether the ecological relevance of biological motion can also distort perceived size. We asked observers to judge the size of point-light walkers (PLWs), configurations of dots whose movements induce the perception of human movement, and visually matched control stimuli (inverted PLWs). We find that upright PLWs are consistently judged as larger than inverted PLWs, while static point-light figures do not elicit the same effect. We also show the phenomenon using an indirect paradigm: observers judged the relative size of a disc that followed an inverted PLW larger than a disc following an upright PLW. We interpret this as a contrast effect: The upright PLW is perceived larger and thus the subsequent disc is judged smaller. Together, these results demonstrate that ecologically relevant biological-motion stimuli are perceived larger than visually matched control stimuli. Our findings present a novel case of illusory size perception, where ecological importance leads to a distorted perception of size.

  4. Materialised Ideals Sizes and Beauty

    Directory of Open Access Journals (Sweden)

    Kirsi Laitala

    2011-04-01

    Full Text Available Today’s clothing industry is based on a system where clothes are made in ready-to-wear sizes and meant to fit most people. Studies have pointed out that consumers are discontent with the use of these systems: size designations are not accurate enough to find clothing that fits, and different sizes are poorly available. This article discusses in depth who these consumers are, and which consumer groups are the most dissatisfied with today’s sizing systems. Results are based on a web survey where 2834 Nordic consumers responded, complemented with eight in-depth interviews, market analysis on clothing sizes and in-store trouser size measurements. Results indicate that higher shares of the consumers who have a body out of touch with the existing beauty ideals express discontentment with the sizing systems and the poor selection available. In particular, large women, very large men, and thin, short men are those who experience less priority in clothing stores and have more difficulties in finding clothes that fit. Consumers tend to blame themselves when the clothes do not fit their bodies, while our study points out that the industry is to blame as they do not produce clothing for all customers.

  5. Effect of particle size on kinetics crystallization of an iron-rich glass

    OpenAIRE

    Romero, Maximina; Kovacova, Milota; Rincón López, Jesús María

    2008-01-01

    The effect of glass particle size on the crystallization kinetics of an iron-rich glass from a nickel leaching waste has been investigated by means of differential thermal analysis (DTA). The results show that the crystallization of a pyroxene phase occurs by bulk nucleation from a constant number of nuclei. The crystallization mode and the dimensionality of crystals are strongly dependent of the glass particle size, being 100µm the critical size. Glass fractions with particle size >100µm sho...

  6. Cavitation erosion size scale effects

    Science.gov (United States)

    Rao, P. V.; Buckley, D. H.

    1984-01-01

    Size scaling in cavitation erosion is a major problem confronting the design engineers of modern high speed machinery. An overview and erosion data analysis presented in this paper indicate that the size scale exponent n in the erosion rate relationship as a function of the size or diameter can vary from 1.7 to 4.9 depending on the type of device used. There is, however, a general agreement as to the values of n if the correlations are made with constant cavitation number.

  7. Analog design centering and sizing

    CERN Document Server

    Graeb, Helmut E

    2007-01-01

    Here is a compendium of fundamental problem formulations of analog design centering and sizing. It provides a differentiated knowledge about the many tasks of analog design centering and sizing. In particular, coverage formulates the worst-case problem. The book stands at the interface between process technology and design technology, detailing how the two are required to reach a solution. It presents a mathematically founded description based on numerical optimization and statistics. This volume will enable analog and mixed-signal designers to assess CAD solution methods that are presented to them as well as help developers of analog CAD tools to formulate and develop solution approaches for analog design centering and sizing.

  8. Single-phase DECT with VNCT compared with three-phase CTU in patients with haematuria

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jung Jae; Park, Byung Kwan; Kim, Chan Kyo [Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Seoul (Korea, Republic of)

    2016-10-15

    To retrospectively evaluate the diagnostic performance of single-phase dual-energy CT (DECT) with virtual non-contrast CT (VNCT) compared with three-phase CT urography (CTU) in patients with haematuria. A total of 296 patients underwent three-phase CTU (NCT at 120 kVp; nephrographic phase and excretory phase DECTs at 140 kVp and 80 kVp) owing to haematuria. Diagnostic performances of CT scans were compared for detecting urothelial tumours and urinary stones. Dose-length product (DLP) was compared in relation to single-phase DECT and three-phase CTU Dose-length product (DLP) was compared in relation to single-phase DECT and three-phase CTU. Sensitivity and specificity for tumour were 95 % (19/20) and 98.9 % (273/276) on CTU, 95 % (19/20) and 98.2 % (271/276) on nephrographic phase DECT, and 90 % (18/20) and 98.2 % (271/276) on excretory phase DECT (P > 0.1). Of the 148 stones detected on NCT, 108 (73 %) and 100 (67.6 %) were detected on nephrographic phase and excretory phase VNCTs, respectively. The mean size of stones undetected on nephrographic and excretory VNCTs was measured as 1.5 ± 0.5 mm and 1.6 ± 0.6 mm, respectively. The mean DLPs of three-phase CTU, nephrographic phase DECT and excretory phase DECT were 1076 ± 248 mGy . cm, 410 ± 98 mGy . cm, and 360 ± 87 mGy . cm, respectively (P < 0.001). Single-phase DECT has a potential to replace three-phase CTU for detecting tumours with a lower radiation dose. (orig.)

  9. Lipidic phase membrane protein serial femtosecond crystallography.

    Science.gov (United States)

    Johansson, Linda C; Arnlund, David; White, Thomas A; Katona, Gergely; Deponte, Daniel P; Weierstall, Uwe; Doak, R Bruce; Shoeman, Robert L; Lomb, Lukas; Malmerberg, Erik; Davidsson, Jan; Nass, Karol; Liang, Mengning; Andreasson, Jakob; Aquila, Andrew; Bajt, Saša; Barthelmess, Miriam; Barty, Anton; Bogan, Michael J; Bostedt, Christoph; Bozek, John D; Caleman, Carl; Coffee, Ryan; Coppola, Nicola; Ekeberg, Tomas; Epp, Sascha W; Erk, Benjamin; Fleckenstein, Holger; Foucar, Lutz; Graafsma, Heinz; Gumprecht, Lars; Hajdu, Janos; Hampton, Christina Y; Hartmann, Robert; Hartmann, Andreas; Hauser, Günter; Hirsemann, Helmut; Holl, Peter; Hunter, Mark S; Kassemeyer, Stephan; Kimmel, Nils; Kirian, Richard A; Maia, Filipe R N C; Marchesini, Stefano; Martin, Andrew V; Reich, Christian; Rolles, Daniel; Rudek, Benedikt; Rudenko, Artem; Schlichting, Ilme; Schulz, Joachim; Seibert, M Marvin; Sierra, Raymond G; Soltau, Heike; Starodub, Dmitri; Stellato, Francesco; Stern, Stephan; Strüder, Lothar; Timneanu, Nicusor; Ullrich, Joachim; Wahlgren, Weixiao Y; Wang, Xiaoyu; Weidenspointner, Georg; Wunderer, Cornelia; Fromme, Petra; Chapman, Henry N; Spence, John C H; Neutze, Richard

    2012-01-29

    X-ray free electron laser (X-FEL)-based serial femtosecond crystallography is an emerging method with potential to rapidly advance the challenging field of membrane protein structural biology. Here we recorded interpretable diffraction data from micrometer-sized lipidic sponge phase crystals of the Blastochloris viridis photosynthetic reaction center delivered into an X-FEL beam using a sponge phase micro-jet.

  10. Thermal Fluctuations in Electroweak Phase Transition

    Science.gov (United States)

    Shiromizu, T.; Morikawa, M.; Yokoyama, J.

    1995-11-01

    We estimate the amplitude of thermal fluctuations by calculating the typical size of subcritical bubbles in cosmological electroweak phase transition and show that this thermal fluctuation effect drastically changes dynamics of the phase transition from the ordinary first order type with supercooling. From this fact, we conclude that the standard electroweak baryogenesis scenario associated with such a first order transition does not work in the minimal standard model in certain conditions.

  11. Sample size determination and power

    CERN Document Server

    Ryan, Thomas P, Jr

    2013-01-01

    THOMAS P. RYAN, PhD, teaches online advanced statistics courses for Northwestern University and The Institute for Statistics Education in sample size determination, design of experiments, engineering statistics, and regression analysis.

  12. Analysis of glass fibre sizing

    DEFF Research Database (Denmark)

    Petersen, Helga Nørgaard; Kusano, Yukihiro; Brøndsted, Povl

    2014-01-01

    Glass fibre reinforced polymer composites are widely used for industrial and engineering applications which include construction, aerospace, automotive and wind energy industry. During the manufacturing glass fibres, they are surface-treated with an aqueous solution. This process and the treated...... surfaces are called sizing. The sizing influences the properties of the interface between fibres and a matrix, and subsequently affects mechanical properties of composites. In this work the sizing of commercially available glass fibres was analysed so as to study the composition and chemical structures....... Soxhlet extraction was used to extract components of the sizing from the glass fibres. The glass fibres, their extracts and coated glass plates were analysed by Thermo-Gravimetric Analysis combined with a mass spectrometer (TGA-MS), and Attenuated Total Reflectance Fourier Transform Infrared (ATR...

  13. Aerosol Size Distributions In Auckland.

    Czech Academy of Sciences Publication Activity Database

    Coulson, G.; Olivares, G.; Talbot, Nicholas

    2016-01-01

    Roč. 50, č. 1 (2016), s. 23-28 E-ISSN 1836-5876 Institutional support: RVO:67985858 Keywords : aerosol size distribution * particle number concentration * roadside Subject RIV: CF - Physical ; Theoretical Chemistry

  14. The size of the nucleosome

    DEFF Research Database (Denmark)

    Bohr, Jakob; Olsen, Kasper

    2011-01-01

    The structural origin of the size of the 11 nm nucleosomal disc is addressed. On the nanometer length-scale the organization of DNA as chromatin in the chromosomes involves a coiling of DNA around the histone core of the nucleosome. We suggest that the size of the nucleosome core particle...... is dictated by the fulfillment of two criteria: One is optimizing the volume fraction of the DNA double helix; this requirement for close-packing has its root in optimizing atomic and molecular interactions. The other criterion being that of having a zero strain-twist coupling; being a zero-twist structure......-pairs of the linker-DNA is included the estimate of the size of an ideal nucleosome is in close agreement with the experimental numbers. Interestingly, the size of the nucleosome is shown to be a consequence of intrinsic properties of the DNA double helix....

  15. Size scaling of static friction.

    Science.gov (United States)

    Braun, O M; Manini, Nicola; Tosatti, Erio

    2013-02-22

    Sliding friction across a thin soft lubricant film typically occurs by stick slip, the lubricant fully solidifying at stick, yielding and flowing at slip. The static friction force per unit area preceding slip is known from molecular dynamics (MD) simulations to decrease with increasing contact area. That makes the large-size fate of stick slip unclear and unknown; its possible vanishing is important as it would herald smooth sliding with a dramatic drop of kinetic friction at large size. Here we formulate a scaling law of the static friction force, which for a soft lubricant is predicted to decrease as f(m)+Δf/A(γ) for increasing contact area A, with γ>0. Our main finding is that the value of f(m), controlling the survival of stick slip at large size, can be evaluated by simulations of comparably small size. MD simulations of soft lubricant sliding are presented, which verify this theory.

  16. Phase equilibrium engineering

    CERN Document Server

    Brignole, Esteban Alberto

    2013-01-01

    Traditionally, the teaching of phase equilibria emphasizes the relationships between the thermodynamic variables of each phase in equilibrium rather than its engineering applications. This book changes the focus from the use of thermodynamics relationships to compute phase equilibria to the design and control of the phase conditions that a process needs. Phase Equilibrium Engineering presents a systematic study and application of phase equilibrium tools to the development of chemical processes. The thermodynamic modeling of mixtures for process development, synthesis, simulation, design and

  17. Grain size distribution in sheared polycrystals

    Science.gov (United States)

    Sarkar, Tanmoy; Biswas, Santidan; Chaudhuri, Pinaki; Sain, Anirban

    2017-12-01

    Plastic deformation in solids induced by external stresses is of both fundamental and practical interest. Using both phase field crystal modeling and molecular dynamics simulations, we study the shear response of monocomponent polycrystalline solids. We subject mesocale polycrystalline samples to constant strain rates in a planar Couette flow geometry for studying its plastic flow, in particular its grain deformation dynamics. As opposed to equilibrium solids where grain dynamics is mainly driven by thermal diffusion, external stress/strain induce a much higher level of grain deformation activity in the form of grain rotation, coalescence, and breakage, mediated by dislocations. Despite this, the grain size distribution of this driven system shows only a weak power-law correction to its equilibrium log-normal behavior. We interpret the grain reorganization dynamics using a stochastic model.

  18. CrowdPhase: crowdsourcing the phase problem

    Energy Technology Data Exchange (ETDEWEB)

    Jorda, Julien; Sawaya, Michael R. [Institute for Genomics and Proteomics, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); Yeates, Todd O., E-mail: yeates@mbi.ucla.edu [Institute for Genomics and Proteomics, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); Molecular Biology Institute, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); University of California, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States)

    2014-06-01

    The idea of attacking the phase problem by crowdsourcing is introduced. Using an interactive, multi-player, web-based system, participants work simultaneously to select phase sets that correspond to better electron-density maps in order to solve low-resolution phasing problems. The human mind innately excels at some complex tasks that are difficult to solve using computers alone. For complex problems amenable to parallelization, strategies can be developed to exploit human intelligence in a collective form: such approaches are sometimes referred to as ‘crowdsourcing’. Here, a first attempt at a crowdsourced approach for low-resolution ab initio phasing in macromolecular crystallography is proposed. A collaborative online game named CrowdPhase was designed, which relies on a human-powered genetic algorithm, where players control the selection mechanism during the evolutionary process. The algorithm starts from a population of ‘individuals’, each with a random genetic makeup, in this case a map prepared from a random set of phases, and tries to cause the population to evolve towards individuals with better phases based on Darwinian survival of the fittest. Players apply their pattern-recognition capabilities to evaluate the electron-density maps generated from these sets of phases and to select the fittest individuals. A user-friendly interface, a training stage and a competitive scoring system foster a network of well trained players who can guide the genetic algorithm towards better solutions from generation to generation via gameplay. CrowdPhase was applied to two synthetic low-resolution phasing puzzles and it was shown that players could successfully obtain phase sets in the 30° phase error range and corresponding molecular envelopes showing agreement with the low-resolution models. The successful preliminary studies suggest that with further development the crowdsourcing approach could fill a gap in current crystallographic methods by making it

  19. Totally asymmetric exclusion processes with particles of arbitrary size

    CERN Document Server

    Lakatos, G

    2003-01-01

    The steady-state currents and densities of a one-dimensional totally asymmetric exclusion process (TASEP) with particles that occlude an integer number (d) of lattice sites are computed using various mean-field approximations and Monte Carlo simulations. TASEPs featuring particles of arbitrary size are relevant for modelling systems such as mRNA translation, vesicle locomotion along microtubules and protein sliding along DNA. We conjecture that the nonequilibrium steady-state properties separate into low-density, high-density, and maximal current phases similar to those of the standard (d = 1) TASEP. A simple mean-field approximation for steady-state particle currents and densities is found to be inaccurate. However, we find local equilibrium particle distributions derived from a discrete Tonks gas partition function yield apparently exact currents within the maximal current phase. For the boundary-limited phases, the equilibrium Tonks gas distribution cannot be used to predict currents, phase boundaries, or ...

  20. The small-sized ultraprecision sensor for measuring linear displacements

    Science.gov (United States)

    Lushnikov, D. S.; Zherdev, A. Y.; Odinokov, S. B.; Markin, V. V.; Gurylev, O. A.; Shishova, M. V.

    2017-06-01

    The article describes a new optical scheme of noncontact sensor for measuring linear displacement - linear encoder. This sensor is an optical device in which the measurement of displacement is performed by analyzing the optical signal, which pass through two diffraction gratings, one of which is moved relative to the other. The optical signal is obtained by the diffraction of light in these diffraction gratings and subsequent interference of diffracted beams. Often this type of sensors are multi-channel devices with symmetrically positioned of detectors. This scheme is proposed to use a multisection phase mask that allows to make a small-sized sensor. Sections of this multi-section phase mask are the optical windows and they made the final interference signals to be shifted relative to each other in phase. The number of sections in the multi-section phase mask can be varied. Estimated sufficient number of sections is four or more.

  1. Cellular detonations in nano-sized aluminum particle gas suspensions

    Science.gov (United States)

    Khmel, TA

    2017-10-01

    Formation of cellular detonation structures in monodisperse nano-sized aluminum particle – oxygen suspensions is studied by methods of numerical simulations of two-dimensional detonation flows. The detonation combustion are described within the semi-empirical model developed earlier which takes into account transition of the regime of aluminum particle combustion from diffusion to kinetic for micro-sized and nano-sized particles. The free-molecular effects are considered in the processes of heat and velocity relaxation of the phases. The specific features of the cellular detonation of nanoparticle suspensions comparing with micron-sized suspensions are irregular cellular structures, much higher pick pressure values, and relatively larger detonation cells. This is due to high value of activation energy of reduced chemical reaction of aluminum particle combustion in kinetic regime.

  2. Genome Size and Species Diversification.

    Science.gov (United States)

    Kraaijeveld, Ken

    2010-12-01

    Theoretically, there are reasons to believe that large genome size should favour speciation. Several major factors contributing to genome size, such as duplications and transposable element activity have been proposed to facilitate the formation of new species. However, it is also possible that small genome size promotes speciation. For example, selection for genome reduction may be resolved in different ways in incipient species, leading to incompatibilities. Mutations and chromosomal rearrangements may also be more stably inherited in smaller genomes. Here I review the following lines of empirical evidence bearing on this question: (i) Correlations between genome size and species richness of taxa are often negative. (ii) Fossil evidence in lungfish shows that the accumulation of DNA in the genomes of this group coincided with a reduction in species diversity. (iii) Estimates of speciation interval in mammals correlate positively with genome size. (iv) Genome reductions are inferred at the base of particular species radiations and genome expansions at the base of others. (v) Insect clades that have been increasing in diversity up to the present have smaller genomes than clades that have remained stable or have decreased in diversity. The general pattern emerging from these observations is that higher diversification rates are generally found in small-genome taxa. Since diversification rates are the net effect of speciation and extinction, large genomes may thus either constrain speciation rate, increase extinction rate, or both. I argue that some of the cited examples are unlikely to be explained by extinction alone.

  3. Genome size variation in Begonia.

    Science.gov (United States)

    Dewitte, Angelo; Leus, Leen; Eeckhaut, Tom; Vanstechelman, Ives; Van Huylenbroeck, Johan; Van Bockstaele, Erik

    2009-10-01

    The genome sizes of a Begonia collection comprising 37 species and 23 hybrids of African, Asiatic, Middle American, and South American origin were screened using flow cytometry. Within the collection, 1C values varied between 0.23 and 1.46 pg DNA. Genome sizes were, in most cases, not positively correlated with chromosome number, but with pollen size. A 12-fold difference in mean chromosome size was found between the genotypes with the largest and smallest chromosomes. In general, chromosomes from South American genotypes were smaller than chromosomes of African, Asian, or Middle American genotypes, except for B. boliviensis and B. pearcei. Cytological chromosome studies in different genotypes showed variable chromosome numbers, length, width, and total chromosome volume, which confirmed the diversity in genome size. Large secondary constrictions were present in several investigated genotypes. These data show that chromosome number and structure exhibit a great deal of variation within the genus Begonia, and likely help to explain the large number of taxa found within the genus.

  4. Experiments on clutch size and nest size in passerine birds.

    Science.gov (United States)

    Slagsvold, Tore

    1989-08-01

    Results of experiments on three passerine species suggest that brood size may be constrained by nest size, since the breeding success of pairs provided with large nestcups was greater than that of those provided with small artificial nestcups. These results may have important implications, e.g. to the design of experiments involving manipulation of clutch and brood size. A small nestcup is requisite for successful hatching during the incubation period, but a large one for successful rearing during the nestling period. In nature this difference may select for types of nesting materials that are elastic, such as mosses and lichens. However, experiments showed that such materials rapidly absorb rainwater but only slowly dry out. In addition, because large nests dry out more slowly than small nests, selection will favour small nests among those open-nesting species that have exposed nests. A further possible nest size constraint on open-nesters is nest predation. However, no difference in the predation rate was found in experiments with small and large artificial nests.

  5. Size-related mortality due to gnathiid isopod micropredation correlates with settlement size in coral reef fishes

    Science.gov (United States)

    Grutter, A. S.; Blomberg, S. P.; Fargher, B.; Kuris, A. M.; McCormick, M. I.; Warner, R. R.

    2017-06-01

    The transition between the planktonic and the benthic habitat is a critical period for the larvae of many demersal marine organisms. Understanding the potential constraints on the timing of this habitat transition, called settlement, is important to understanding their biology. Size-specific mortality can set the limits on lifestyle and help explain ontogenetic habitat shifts. We examined whether size-based mortality risks after settlement may include micropredation by ectoparasites by testing whether survival of settlement-stage fish varies with fish size when exposed to a reef-associated micropredator. Fish (14 species) were exposed to one blood-sucking gnathiid isopod overnight, with appropriate controls; gnathiid feeding success and survival, and fish mortality were recorded relative to fish size. After adjusting for fish relatedness, we found the relationship between fish mortality and size differed with gnathiid exposure: for gnathiid-exposed fish, the mean mortality of the smallest fish was much higher (57%) than unexposed controls (10%), and decreased to 0% for fish >12 mm standard length (SL); mortality was almost nil in controls. Thus, a predicted optimal size to switch habitat and reduce mortality risk from micropredation should be >12 mm SL. We then asked what species might be at greater risk and if the steep increase in survival at 12 mm SL might coincide with settlement at larger sizes among fishes. Across 102 other species (32 families), 61% settled at ≥12 mm SL. After adjusting for relatedness, mean fish settlement size was 15.0 mm and this was not significantly different from 12 mm. Thus, settlement size clusters around the minimum fish size threshold our gnathiid experiment predicted would be large enough to survive a gnathiid encounter. These results suggest micropredators may contribute to size-selective mortality during settlement processes and are consistent with the hypothesis that the pelagic phase provides fish an escape from certain

  6. Martensitic transformations in nanostructured nitinol: Finite element modeling of grain size and distribution effects

    DEFF Research Database (Denmark)

    Liu, Hong-Sheng; Mishnaevsky, Leon

    2013-01-01

    transformation are totally suppressed. Graded and localized distributions of grain sizes of nitinol were compared with nitinol samples with homogeneous grain size distribution. In the materials with localized region of small grains, it was observed that the martensite rich regions form first on the border......A computational model of martensitic phase transformation in nanostructured nitinol is developed which takes into account the grain size effect. On the basis of the theoretical analysis of the thermodynamic transformation criterion and the energy barrier for phase transformation......, it was demonstrated that the energy barrier for martensitic phase transformation in nanocrystalline nitinol increase drastically with decreasing the grain size. Finite element simulations of phase transformations and structure evolution in nanocrystalline nitinol under mechanical (tensile) loading are carried out...

  7. Phase synchronization in railway timetables

    Science.gov (United States)

    Fretter, C.; Krumov, L.; Weihe, K.; Müller-Hannemann, M.; Hütt, M.-T.

    2010-09-01

    Timetable construction belongs to the most important optimization problems in public transport. Finding optimal or near-optimal timetables under the subsidiary conditions of minimizing travel times and other criteria is a targeted contribution to the functioning of public transport. In addition to efficiency (given, e.g., by minimal average travel times), a significant feature of a timetable is its robustness against delay propagation. Here we study the balance of efficiency and robustness in long-distance railway timetables (in particular the current long-distance railway timetable in Germany) from the perspective of synchronization, exploiting the fact that a major part of the trains run nearly periodically. We find that synchronization is highest at intermediate-sized stations. We argue that this synchronization perspective opens a new avenue towards an understanding of railway timetables by representing them as spatio-temporal phase patterns. Robustness and efficiency can then be viewed as properties of this phase pattern.

  8. Ostwald-ripening and particle size focussing of sub-10 nm NaYF4 upconversion nanocrystals

    Science.gov (United States)

    Rinkel, Thorben; Nordmann, Jörg; Raj, Athira Naduviledathu; Haase, Markus

    2014-11-01

    We have studied the growth behaviour of sub-10 nm NaYF4 upconversion nanocrystals of the hexagonal β-phase and the cubic α-phase. Ostwald-ripening of such particles in oleic acid/octadecene solvent results in broadening of the particle size distribution if the colloid contains particles of one crystal phase only. Narrow size distributions are formed only if β-phase particles grow in the presence of an excess of α-phase particles. Such binary mixtures of α-phase and β-phase particles form intrinsically when colloids of α-phase particles are heated for a sufficiently long time, because seeds of the β-phase nucleate in the solution after some time at high temperatures. Since the number of seeds determines the final size of the β-phase product, control of the nucleation is crucial for controlling the final particle size. We show that the number of β-phase seeds strongly depends on the composition of the α-phase known to form solid solutions Na1-xYF4-x in the range from x = 0 to x = 4/9. Sodium-deficient α-phase particles form a negligible number of β-phase seeds whereas α-phase particles with high sodium content yield a very large number of seeds. By taking advantage of this dependence and modifying the synthesis of the α-phase particles accordingly, small phase-pure β-NaYF4:Yb,Er particles with a size smaller than 6 nm can be prepared in oleic acid/octadecene just as well as much larger particles.We have studied the growth behaviour of sub-10 nm NaYF4 upconversion nanocrystals of the hexagonal β-phase and the cubic α-phase. Ostwald-ripening of such particles in oleic acid/octadecene solvent results in broadening of the particle size distribution if the colloid contains particles of one crystal phase only. Narrow size distributions are formed only if β-phase particles grow in the presence of an excess of α-phase particles. Such binary mixtures of α-phase and β-phase particles form intrinsically when colloids of α-phase particles are heated for a

  9. Modeling and Sizing of Supercapacitors

    Directory of Open Access Journals (Sweden)

    PETREUS, D.

    2008-06-01

    Full Text Available Faced with numerous challenges raised by the requirements of the modern industries for higher power and higher energy, supercapacitors study started playing an important role in offering viable solutions for some of these requirements. This paper presents the surface redox reactions based modeling in order to study the origin of high capacity of EDLC (electrical double-layer capacitor for better understanding the working principles of supercapacitors. Some application-dependent sizing methods are also presented since proper sizing can increase the efficiency and the life cycle of the supercapacitor based systems.

  10. Size of quorum sensing communities

    DEFF Research Database (Denmark)

    Ferkinghoff-Borg, Jesper; Sams, Thomas

    2014-01-01

    Ensembles of bacteria are able to coordinate their phenotypic behavior in accordance with the size, density, and growth state of the ensemble. This is achieved through production and exchange of diffusible signal molecules in a cell–cell regulatory system termed quorum sensing. In the generic...... by a geometric factor which incorporates the boundary conditions constitutes an appropriate size measure. The geometric factor is the square of the radius for a spherical colony or a hemisphere attached to a reflecting surface. If surrounded by a rapidly exchanged medium, the geometric factor is divided by three...

  11. Modelling of phase diagrams of nanoalloys with complex metallic phases: application to Ni-Sn.

    Science.gov (United States)

    Kroupa, A; Káňa, T; Buršík, J; Zemanová, A; Šob, M

    2015-11-14

    A method for modelling of size-dependent phase diagrams was developed by combining the semiempirical CALPHAD method and ab initio calculations of surface stresses for intermetallic phases. A novel approach was devised for the calculation of surface energy, free of systematic errors from the selection of different parameters of the software (e.g. number of the k-points) and for handling layered structures and off-stoichiometric slabs. Our approach allows the determination of complex size-dependent phase diagrams of systems with intermetallic phases, which was not possible up to now. The method was verified for the modelling of the phase diagram of the Ni-Sn system and basic comparison with rare experimental results was shown. There is reasonable agreement between the calculated and experimental results. The modelling of size-dependent phase diagrams of real systems allows the prediction of phase equilibria existing in nanosystems and possible changes in material properties. There is a need for such knowledge and the existence of reliable data for simpler systems is crucial for further application of this approach. This should motivate future experimental work.

  12. Light scattering by lunar-like particle size distributions

    Science.gov (United States)

    Goguen, Jay D.

    1991-01-01

    A fundamental input to models of light scattering from planetary regoliths is the mean phase function of the regolith particles. Using the known size distribution for typical lunar soils, the mean phase function and mean linear polarization for a regolith volume element of spherical particles of any composition were calculated from Mie theory. The two contour plots given here summarize the changes in the mean phase function and linear polarization with changes in the real part of the complex index of refraction, n - ik, for k equals 0.01, the visible wavelength 0.55 micrometers, and the particle size distribution of the typical mature lunar soil 72141. A second figure is a similar index-phase surface, except with k equals 0.1. The index-phase surfaces from this survey are a first order description of scattering by lunar-like regoliths of spherical particles of arbitrary composition. They form the basis of functions that span a large range of parameter-space.

  13. Bilayer thickness mismatch controls domain size in model membranes.

    Science.gov (United States)

    Heberle, Frederick A; Petruzielo, Robin S; Pan, Jianjun; Drazba, Paul; Kučerka, Norbert; Standaert, Robert F; Feigenson, Gerald W; Katsaras, John

    2013-05-08

    The observation of lateral phase separation in lipid bilayers has received considerable attention, especially in connection to lipid raft phenomena in cells. It is widely accepted that rafts play a central role in cellular processes, notably signal transduction. While micrometer-sized domains are observed with some model membrane mixtures, rafts much smaller than 100 nm-beyond the reach of optical microscopy-are now thought to exist, both in vitro and in vivo. We have used small-angle neutron scattering, a probe free technique, to measure the size of nanoscopic membrane domains in unilamellar vesicles with unprecedented accuracy. These experiments were performed using a four-component model system containing fixed proportions of cholesterol and the saturated phospholipid 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), mixed with varying amounts of the unsaturated phospholipids 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). We find that liquid domain size increases with the extent of acyl chain unsaturation (DOPC:POPC ratio). Furthermore, we find a direct correlation between domain size and the mismatch in bilayer thickness of the coexisting liquid-ordered and liquid-disordered phases, suggesting a dominant role for line tension in controlling domain size. While this result is expected from line tension theories, we provide the first experimental verification in free-floating bilayers. Importantly, we also find that changes in bilayer thickness, which accompany changes in the degree of lipid chain unsaturation, are entirely confined to the disordered phase. Together, these results suggest how the size of functional domains in homeothermic cells may be regulated through changes in lipid composition.

  14. Bilayer Thickness Mismatch Controls Domain Size in Model Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Heberle, Frederick A [ORNL; Petruzielo, Robin S [ORNL; Pan, Jianjun [ORNL; Drazba, Paul [ORNL; Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia); Feigenson, Gerald [Cornell University; Katsaras, John [ORNL

    2013-01-01

    The observation of lateral phase separation in lipid bilayers has received considerable attention, especially in connection to lipid raft phenomena in cells. It is widely accepted that rafts play a central role in cellular processes, notably signal transduction. While micrometer-sized domains are observed with some model membrane mixtures, rafts much smaller than 100 nm beyond the reach of optical microscopy are now thought to exist, both in vitro and in vivo. We have used small-angle neutron scattering, a probe free technique, to measure the size of nanoscopic membrane domains in unilamellar vesicles with unprecedented accuracy. These experiments were performed using a four-component model system containing fixed proportions of cholesterol and the saturated phospholipid 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), mixed with varying amounts of the unsaturated phospholipids 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dioleoylsn- glycero-3-phosphocholine (DOPC). We find that liquid domain size increases with the extent of acyl chain unsaturation (DOPC:POPC ratio). Furthermore, we find a direct correlation between domain size and the mismatch in bilayer thickness of the coexisting liquid-ordered and liquid-disordered phases, suggesting a dominant role for line tension in controlling domain size. While this result is expected from line tension theories, we provide the first experimental verification in free-floating bilayers. Importantly, we also find that changes in bilayer thickness, which accompany changes in the degree of lipid chain unsaturation, are entirely confined to the disordered phase. Together, these results suggest how the size of functional domains in homeothermic cells may be regulated through changes in lipid composition.

  15. Grain-size considerations for optoelectronic multistage interconnection networks.

    Science.gov (United States)

    Krishnamoorthy, A V; Marchand, P J; Kiamilev, F E; Esener, S C

    1992-09-10

    This paper investigates, at the system level, the performance-cost trade-off between optical and electronic interconnects in an optoelectronic interconnection network. The specific system considered is a packet-switched, free-space optoelectronic shuffle-exchange multistage interconnection network (MIN). System bandwidth is used as the performance measure, while system area, system power, and system volume constitute the cost measures. A detailed design and analysis of a two-dimensional (2-D) optoelectronic shuffle-exchange routing network with variable grain size K is presented. The architecture permits the conventional 2 x 2 switches or grains to be generalized to larger K x K grain sizes by replacing optical interconnects with electronic wires without affecting the functionality of the system. Thus the system consists of log(k) N optoelectronic stages interconnected with free-space K-shuffles. When K = N, the MIN consists of a single electronic stage with optical input-output. The system design use an effi ient 2-D VLSI layout and a single diffractive optical element between stages to provide the 2-D K-shuffle interconnection. Results indicate that there is an optimum range of grain sizes that provides the best performance per cost. For the specific VLSI/GaAs multiple quantum well technology and system architecture considered, grain sizes larger than 256 x 256 result in a reduced performance, while grain sizes smaller than 16 x 16 have a high cost. For a network with 4096 channels, the useful range of grain sizes corresponds to approximately 250-400 electronic transistors per optical input-output channel. The effect of varying certain technology parameters such as the number of hologram phase levels, the modulator driving voltage, the minimum detectable power, and VLSI minimum feature size on the optimum grain-size system is studied. For instance, results show that using four phase levels for the interconnection hologram is a good compromise for the cost

  16. A multivariate rank test for comparing mass size distributions

    KAUST Repository

    Lombard, F.

    2012-04-01

    Particle size analyses of a raw material are commonplace in the mineral processing industry. Knowledge of particle size distributions is crucial in planning milling operations to enable an optimum degree of liberation of valuable mineral phases, to minimize plant losses due to an excess of oversize or undersize material or to attain a size distribution that fits a contractual specification. The problem addressed in the present paper is how to test the equality of two or more underlying size distributions. A distinguishing feature of these size distributions is that they are not based on counts of individual particles. Rather, they are mass size distributions giving the fractions of the total mass of a sampled material lying in each of a number of size intervals. As such, the data are compositional in nature, using the terminology of Aitchison [1] that is, multivariate vectors the components of which add to 100%. In the literature, various versions of Hotelling\\'s T 2 have been used to compare matched pairs of such compositional data. In this paper, we propose a robust test procedure based on ranks as a competitor to Hotelling\\'s T 2. In contrast to the latter statistic, the power of the rank test is not unduly affected by the presence of outliers or of zeros among the data. © 2012 Copyright Taylor and Francis Group, LLC.

  17. Variability in human body size

    Science.gov (United States)

    Annis, J. F.

    1978-01-01

    The range of variability found among homogeneous groups is described and illustrated. Those trends that show significantly marked differences between sexes and among a number of racial/ethnic groups are also presented. Causes of human-body size variability discussed include genetic endowment, aging, nutrition, protective garments, and occupation. The information is presented to aid design engineers of space flight hardware and equipment.

  18. Class size versus class composition

    DEFF Research Database (Denmark)

    Jones, Sam

    Raising schooling quality in low-income countries is a pressing challenge. Substantial research has considered the impact of cutting class sizes on skills acquisition. Considerably less attention has been given to the extent to which peer effects, which refer to class composition, also may affect...

  19. Size, productivity, and international banking

    NARCIS (Netherlands)

    Buch, Claudia M.; Koch, Catherine T.; Koetter, Michael

    2011-01-01

    Heterogeneity in size and productivity is central to models that explain which manufacturing firms expert. This study presents descriptive evidence on similar heterogeneity among international banks as financial services providers. A novel and detailed bank-level data set reveals the volume and mode

  20. On the optimal sizing problem

    DEFF Research Database (Denmark)

    Vidal, Rene Victor Valqui

    1994-01-01

    The paper studies the problem of determining the number and dimensions of sizes of apparel so as to maximize profits. It develops a simple one-variable bisection search algorithm that gives the optimal solution. An example is solved interactively using a Macintosh LC and Math CAD, a mathematical...

  1. Food aroma affects bite size

    NARCIS (Netherlands)

    Wijk, de R.A.; Polet, I.A.; Boek, W.; Coenraad, S.; Bult, J.H.F.

    2012-01-01

    Background
    To evaluate the effect of food aroma on bite size, a semisolid vanilla custard dessert was delivered repeatedly into the mouth of test subjects using a pump while various concentrations of cream aroma were presented retronasally to the nose. Termination of the pump, which determined

  2. Automated measurement of diatom size

    Science.gov (United States)

    Spaulding, Sarah A.; Jewson, David H.; Bixby, Rebecca J.; Nelson, Harry; McKnight, Diane M.

    2012-01-01

    Size analysis of diatom populations has not been widely considered, but it is a potentially powerful tool for understanding diatom life histories, population dynamics, and phylogenetic relationships. However, measuring cell dimensions on a light microscope is a time-consuming process. An alternative technique has been developed using digital flow cytometry on a FlowCAM® (Fluid Imaging Technologies) to capture hundreds, or even thousands, of images of a chosen taxon from a single sample in a matter of minutes. Up to 30 morphological measures may be quantified through post-processing of the high resolution images. We evaluated FlowCAM size measurements, comparing them against measurements from a light microscope. We found good agreement between measurement of apical cell length in species with elongated, straight valves, including small Achnanthidium minutissimum (11-21 µm) and largeDidymosphenia geminata (87–137 µm) forms. However, a taxon with curved cells, Hannaea baicalensis (37–96 µm), showed differences of ~ 4 µm between the two methods. Discrepancies appear to be influenced by the choice of feret or geodesic measurement for asymmetric cells. We describe the operating conditions necessary for analysis of size distributions and present suggestions for optimal instrument conditions for size analysis of diatom samples using the FlowCAM. The increased speed of data acquisition through use of imaging flow cytometers like the FlowCAM is an essential step for advancing studies of diatom populations.

  3. Optoelectronic Infrastructure for RF/Optical Phased Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Optoelectronic integrated circuits offer radiation-hard solutions for satellite systems with much improved SWPB (size, weight, power and bandwidth). The phased array...

  4. Phase Field Approach

    Science.gov (United States)

    Koyama, Toshiyuki

    The term phase field has recently become known across many fields of materials science. The meaning of phase field is the spatial and temporal order parameter field defined in a continuum-diffused interface model. By using the phase field order parameters, many types of complex microstructure changes observed in materials science are described effectively. This methodology has been referred to as the phase field method, phase field simulation, phase field modeling, phase field approach, etc. In this chapter, the basic concept and theoretical background for the phase field approach is explained in Sects. 21.1 and 21.2. The overview of recent applications of the phase field method is demonstrated in Sects. 21.3 to 21.6.

  5. Phase structure of a surface model with many fine holes.

    Science.gov (United States)

    Koibuchi, H

    2008-07-01

    We study the phase structure of a surface model by using the canonical Monte Carlo simulation technique on triangulated, fixed connectivity, and spherical surfaces with many fine holes. The size of a hole is assumed to be of the order of lattice spacing (or bond length) and hence can be negligible compared to the surface size in the thermodynamic limit. We observe in the numerical data that the model undergoes a first-order collapsing transition between the smooth phase and the collapsed phase. Moreover the Hasudorff dimension H remains in the physical bound, i.e., H model in this paper and the previous one with many holes, whose size is of the order of the surface size, because the previous surface model with large-sized holes has only the collapsing transition and no transition of surface fluctuations.

  6. Analysis and simulation of phase transformation kinetics of zeolite A from amorphous phases

    CERN Document Server

    Marui, Y; Uchida, H; Takiyama, H

    2003-01-01

    Experiments on transformation rates of zeolite A from amorphous phases at different feed rates to alter the particle size of the amorphous phases were carried out to analyze the kinetics of the transformation, and were analyzed by performing simulation of the transformation. A clear dependence of the induction time for nucleation of zeolite A crystals on the surface area of the amorphous phase was recognized, indicating that the nucleation of zeolite A was heterogeneous and the nucleation rate was almost proportional to the size of the amorphous particles. From the simulation, the mechanism of the transformation was found to be heterogeneous nucleation of zeolite A crystals on the surface of amorphous particles followed by solution mediated phase transformation, and the transformation kinetics were well reproduced at different feed rates. (author)

  7. Finite-size scaling of interface free energies in the 3d Ising model

    CERN Document Server

    Pepé, M; Forcrand, Ph. de

    2002-01-01

    We perform a study of the universality of the finite size scaling functions of interface free energies in the 3d Ising model. Close to the hot/cold phase transition, we observe very good agreement with the same scaling functions of the 4d SU(2) Yang--Mills theory at the deconfinement phase transition.

  8. Measuring bubble, drop and particle sizes in multiphase systems with ultrasound

    NARCIS (Netherlands)

    Cents, A.H.G.; Brilman, Derk Willem Frederik; Versteeg, Geert; Wijnstra, P.J.; Wijnstra, P.J.; Regtien, Paulus P.L.

    2004-01-01

    A technique is developed for measurement of bubble, droplet and particle-size distributions in multiphase systems, based on the propagation speed and attenuation of ultrasound. The measurement of the size distribution of the dispersed phase in multiphase systems was desired to analyze the

  9. Measuring Bubble, Drop and Particle Sizes in Multiphase Systems with Ultrasound

    NARCIS (Netherlands)

    Cents, A.H.G.; Brilman, D.W.F.; Versteeg, G.F.; Wijnstra, P.J.; Regtien, P.P.L.

    2004-01-01

    A technique is developed for measurement of bubble, droplet and particle-size distributions in multiphase systems, based on the propagation speed and attenuation of ultrasound. The measurement of the size distribution of the dispersed phase in multiphase systems was desired to analyze the

  10. Pigeons use distinct stop phases to control pecking.

    Science.gov (United States)

    Theunissen, Leslie M; Reid, Thomas; Troje, Nikolaus F

    2017-02-01

    Pecking at small targets requires accurate spatial coordination of the head. Planning of the peck has been proposed to occur in two distinct stop phases, but although this idea has now been around for a long time, the specific functional roles of these stop phases remain unsolved. Here, we investigated the characteristics of the two stop phases using high-speed motion capture and examined their functions with two experiments. In experiment 1, we tested the hypothesis that the second stop phase is used to pre-program the final approach to a target and analyzed head movements while pigeons (Columba livia) pecked at targets of different size. Our results show that the duration of both stop phases significantly increased as stimulus size decreased. We also found significant positive correlations between stimulus size and the distances of the beaks to the stimulus during both stop phases. In experiment 2, we used a two-alternative forced choice task with different levels of difficulty to test the hypothesis that the first stop phase is used to decide between targets. The results indicate that the characteristics of the stop phases do not change with an increasing difficulty between the two choices. Therefore, we conclude that the first stop phase is not exclusively used to decide upon a target to peck at, but also contributes to the function of the second stop phase, which is improving pecking accuracy and planning the final approach to the target. © 2017. Published by The Company of Biologists Ltd.

  11. High temperature phase equilibria and phase diagrams

    CERN Document Server

    Kuo, Chu-Kun; Yan, Dong-Sheng

    2013-01-01

    High temperature phase equilibria studies play an increasingly important role in materials science and engineering. It is especially significant in the research into the properties of the material and the ways in which they can be improved. This is achieved by observing equilibrium and by examining the phase relationships at high temperature. The study of high temperature phase diagrams of nonmetallic systems began in the early 1900s when silica and mineral systems containing silica were focussed upon. Since then technical ceramics emerged and more emphasis has been placed on high temperature

  12. Size effects in crystal plasticity

    DEFF Research Database (Denmark)

    Borg, Ulrik

    2007-01-01

    growth and interaction between neighboring voids, and on a comparison between the developed strain gradient crystal plasticity theory and a discrete dislocation plasticity theory. Furthermore, voids and rigid inclusions in isotropic materials have been studied using a strain gradient plasticity theory......Numerical analyses of plasticity size effects have been carried out for different problems using a developed strain gradient crystal plasticiy theory. The theory employs higher order stresses as work conjugates to slip gradients and uses higher order boundary conditions. Problems on localization...... of plastic flow in a single crystal, grain boundary effects in a bicrystal, and grain size effects in a polycrystal are studied. Single crystals containing micro-scale voids have also been analyzed at different loading conditions with focus on the stress and deformation fields around the voids, on void...

  13. SIZE OF LIVESTOCK AGRICULTURAL OPERATIONS

    Directory of Open Access Journals (Sweden)

    Bazbanela Stere

    2015-07-01

    Full Text Available The main goal of the paper is to map the performance of Romanian farms from the perspective of livestock agricultural operations using principal component analysis technique (PCA and similarities between Romania and other countries from UE. The empirical results reveal that animal breedings farms are grouped into two categories :small and middle sized farms ; and the fact that Romania , one of Europe’s major forces in the field of livestock husbandry, has come to be one of the biggest importers of food products, although, by tradition, it is one of the continent’s countries with ideal conditions for breeding all species of animals. When clustering the countries we observ that in countries such as Greece, Italy, Portugal, Spain, cow farms, for example, do not exceed 10-16 heads and in Holland, England, Denmark, Belgium and France, the average farm size reaches 30-70 heads of milk cows. The cluster analysis revealed that in livestock operations, animal stock is the one that generates production, while the animal number indicates the size of the livestock unit.

  14. A rapid molecular approach for chromosomal phasing.

    Directory of Open Access Journals (Sweden)

    John F Regan

    Full Text Available Determining the chromosomal phase of pairs of sequence variants - the arrangement of specific alleles as haplotypes - is a routine challenge in molecular genetics. Here we describe Drop-Phase, a molecular method for quickly ascertaining the phase of pairs of DNA sequence variants (separated by 1-200 kb without cloning or manual single-molecule dilution. In each Drop-Phase reaction, genomic DNA segments are isolated in tens of thousands of nanoliter-sized droplets together with allele-specific fluorescence probes, in a single reaction well. Physically linked alleles partition into the same droplets, revealing their chromosomal phase in the co-distribution of fluorophores across droplets. We demonstrated the accuracy of this method by phasing members of trios (revealing 100% concordance with inheritance information, and demonstrate a common clinical application by phasing CFTR alleles at genomic distances of 11-116 kb in the genomes of cystic fibrosis patients. Drop-Phase is rapid (requiring less than 4 hours, scalable (to hundreds of samples, and effective at long genomic distances (200 kb.

  15. Therapy Provider Phase Information

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Therapy Provider Phase Information dataset is a tool for providers to search by their National Provider Identifier (NPI) number to determine their phase for...

  16. Digital quadrature phase detection

    Science.gov (United States)

    Smith, J.A.; Johnson, J.A.

    1992-05-26

    A system for detecting the phase of a frequency or phase modulated signal that includes digital quadrature sampling of the frequency or phase modulated signal at two times that are one quarter of a cycle of a reference signal apart, determination of the arctangent of the ratio of a first sampling of the frequency or phase modulated signal to the second sampling of the frequency or phase modulated signal, and a determination of quadrant in which the phase determination is increased by 2[pi] when the quadrant changes from the first quadrant to the fourth quadrant and decreased by 2[pi] when the quadrant changes from the fourth quadrant to the first quadrant whereby the absolute phase of the frequency or phase modulated signal can be determined using an arbitrary reference convention. 6 figs.

  17. Predicting the size of droplets produced through Laplace pressure induced snap-off

    CERN Document Server

    Barkley, Solomon; Weeks, Eric R; Dalnoki-Veress, Kari

    2016-01-01

    Laplace pressure driven snap-off is a technique that is used to produce droplets for emulsions and microfluidics purposes. Previous predictions of droplet size have assumed a quasi-equilibrium low flow limit. We present a simple model to predict droplet sizes over a wide range of flow rates, demonstrating a rich landscape of droplet stability depending on droplet size and growth rate. The model accounts for the easily adjusted experimental parameters of geometry, interfacial tension, and the viscosities of both phases.

  18. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 2 covers the advances in gas phase ion chemistry. The book discusses the stabilities of positive ions from equilibrium gas-phase basicity measurements; the experimental methods used to determine molecular electron affinities, specifically photoelectron spectroscopy, photodetachment spectroscopy, charge transfer, and collisional ionization; and the gas-phase acidity scale. The text also describes the basis of the technique of chemical ionization mass spectrometry; the energetics and mechanisms of unimolecular reactions of positive ions; and the photodissociation

  19. Family size and child development.

    Science.gov (United States)

    Polit, D F

    1982-12-01

    For some time now there has been a multidisciplinary interest in the effects of family size on children's development and on their overall life outcomes. In general, available evidence indicates that children from small families tend to accrue advantages in many developmental areas, while children from larger families are, as a group, relatively disadvantaged. Care needs to be taken when drawing conclusions from correlational research, yet there is growing evidence that even when the social class of families is accounted for, children from smaller families fare better on many measures of development than those from large families. 1 of the best documented research findings is that children from smaller families perform better on tests of intellectual ability than children from large families. Efforts to understand why family size should affect intellectual performance have intensified in recent years. Many explanations have been offered, but the explanation termed the "confluence model" has attracted the most interest and controversy. According to this model, a child's intellectual development is a function of the intellectual environment provided by the family. That environment is conceptualized as the average of absolute intelligence of all family members. A child is born with an absolute intelligence of zero. The arrival of each additional child has the effect of lowering the family's intellectual environment. Thus, children from larger families grow up in a less enriched environment and tend to perform less well on measures of ability. A 2nd component of the confluence model is necessary to explain the phenomenon that "only" children fail to perform as well as might be expected on intelligence tests. According to the confluence model, the only child discontinuity results from the absence of an opportunity to tutor younger siblings. Available evidence indicates that family size exerts an effect on educational and occupational achievement over and above its

  20. Computation of Phase Equilibrium and Phase Envelopes

    DEFF Research Database (Denmark)

    Ritschel, Tobias Kasper Skovborg; Jørgensen, John Bagterp

    and 2) nonideal gases and liquids modeled with cubic equations of state. Next, we derive the equilibrium conditions for an isothermal-isobaric (constant temperature, constant pressure) vapor-liquid equilibrium process (PT flash), and we present a method for the computation of phase envelopes. We......In this technical report, we describe the computation of phase equilibrium and phase envelopes based on expressions for the fugacity coefficients. We derive those expressions from the residual Gibbs energy. We consider 1) ideal gases and liquids modeled with correlations from the DIPPR database...... formulate the involved equations in terms of the fugacity coefficients. We present expressions for the first-order derivatives. Such derivatives are necessary in computationally efficient gradient-based methods for solving the vapor-liquid equilibrium equations and for computing phase envelopes. Finally, we...

  1. Electron concentration and phase stability in NbCr2-based Laves phase alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J.H.; Liaw, P.K. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering; Liu, C.T. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-05-12

    Phase stability in NbCr{sub 2}-based transition-metal Laves phases was studied, based on the data reported for binary X-Cr, Nb-X, and ternary Nb-Cr-X phase diagrams. It was shown that when the atomic size ratios are kept identical, the average electron concentration factor, e/a, is the dominating factor in controlling the phase stability of NbCr{sub 2}-based transition-metal Laves phases. The e/a ratios for different Laves polytypes were determined as followed: with e/a < 5.76, the C15 structure is stabilized; at an e/a range of 5.88--7.53, the C14 structure is stabilized; with e/a > 7.65, the C15 structure is stabilized again. A further increase in the electron concentration factor (e/a > 8) leads to the disordering of the alloy. The electron concentration effect on the phase stability of Mg-based Laves phases and transition-metal A{sub 3}B intermetallic compounds is also reviewed and compared with the present observations in transition-metal Laves phases. In order to verify the e/a/phase stability relationship experimentally, additions of Cu (with e/a = 11) were selected to replace Cr in the NbCr{sub 2} Laves phase. Experimental results for the ternary Nb-Cr-Cu system are reported and discussed in terms of the correlation between the e/a ratio and phase stability in NbCr{sub 2}-based Laves phases. A new phase was found, which has an average composition of Nb-47Cr-3Cu. Within the solubility limit, the electron concentration and phase stability relationship is obeyed in the Nb-Cr-Cu system.

  2. The economics of urban size.

    Science.gov (United States)

    Alonso, W

    1971-01-01

    An aggregative economic approach to the theory of city size is presented along with some empirical findings which suggest that even the largest cities have not yet reached excessive sizes from the point of view of growth and productivity. Urban magnitude is no simple 1 dimensional phenomenon. Modern urban centers are surrounded by very large, diffuse zonal boundaries, within which there are marked variations in the proportion of firms and people associated with that center, and in the intensity of the association. In sum, population does not constitute a conventional, countable set. In general, population will be considered as the basic magnitude and as a conventionally definable number. Most approaches to city size have emphasized the presumed diseconomy of urban scale and have sought to establish that population at which costs per capita are least, regarding this as optimal. It is argued here that both the logic and the factual basis of this approach are faulty. The argument of minimum costs is insufficient in its own terms. Such an objective is reasonable only if output per capita is constant, but it appears that output per capita is an increasing function of urban size. In that case, a more sensible objective of public policy would deal with the relation of outputs and inputs, rather than only with inputs. In every country for which evidence was found, local product per capita (or some index for it, such as income or wages) rises with urban size, and where comparable figures on cost are available, these rise far more slowly if at all. Although all of the data desirable are not available for any single country, the overall pattern is clear. Possibly the most surprising element in the data is the marked decline with increasing density in Social Overhead Captial Stocks (SOCS) per capita. This runs counter to common belief that the bigger the city the more infrastructure per capita is needed and may be the result of such effects as the greater linear quantities of

  3. Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy

    Directory of Open Access Journals (Sweden)

    Chaoqi Shen

    2016-12-01

    Full Text Available The kinetics of hydrogen absorption/desorption can be improved by decreasing particle size down to a few nanometres. However, the associated evolution of activation energy remains unclear. In an attempt to clarify such an evolution with respect to particle size, we electrochemically deposited Mg nanoparticles on a catalytic nickel and noncatalytic titanium substrate. At a short deposition time of 1 h, magnesium particles with a size of 68 ± 11 nm could be formed on the nickel substrate, whereas longer deposition times led to much larger particles of 421 ± 70 nm. Evaluation of the hydrogen desorption properties of the deposited magnesium nanoparticles confirmed the effectiveness of the nickel substrate in facilitating the recombination of hydrogen, but also a significant decrease in activation energy from 56.1 to 37.8 kJ·mol−1 H2 as particle size decreased from 421 ± 70 to 68 ± 11 nm. Hence, the activation energy was found to be intrinsically linked to magnesium particle size. Such a reduction in activation energy was associated with the decrease of path lengths for hydrogen diffusion at the desorbing MgH2/Mg interface. Further reduction in particle size to a few nanometres to remove any barrier for hydrogen diffusion would then leave the single nucleation and growth of the magnesium phase as the only remaining rate-limiting step, assuming that the magnesium surface can effectively catalyse the dissociation/recombination of hydrogen.

  4. Cubatic phase for tetrapods

    NARCIS (Netherlands)

    Blaak, R.; Mulder, B.M.; Frenkel, D.

    2004-01-01

    We investigate the phase behavior of tetrapods, hard nonconvex bodies formed by four rods connected under tetrahedral angles. We predict that, depending on the relative lengths of the rods these particles can form a uniaxial nematic phase, and more surprisingly they can exhibit a cubatic phase, a

  5. MARTENSITIC CREEP RESISTANT STEEL STRENGTHENED BY Z-PHASE

    DEFF Research Database (Denmark)

    2008-01-01

    The present invention relates to steel alloys having a martensitic or martensitic- ferritic structure and comprising Z-phase (CrXN) particles, where X is one or more of the elements V, Nb, Ta, and where the Z-phase particles have an average size of less than 400 nm. The alloy comprises by wt % th...

  6. Scattering Phase Functions of Constituents of Mineral Dust Aerosols ...

    African Journals Online (AJOL)

    The results show that there is increasing asymmetry and complexity of the phase functions with increasing radial sizes for each of the selected constituents: Illite, Kaolinite, Montmorillonte, Hematite, Calcite and Quartz. The behaviour of these constituents as observed by their phase functions provide information on the ...

  7. Differential Phase Detector for Precise Phase Alignment

    CERN Document Server

    Olexa, Jakub

    2016-01-01

    This paper presents a differential phase detector circuit, whose phase-to-voltage characteristic has an extremum when its two input signals are exactly in phase. In this condition all its digital signals are of 50 % duty cycle so that the circuit characteristic does not have a dead zone. This feature allows a precise indication of the zero-phase condition, which is independent of the detector power supply and the offset of its ADC readout. Such a detector is used for a phase alignment of two reference clock signals with frequency about 11 kHz in front-ends processing signals from beam position monitors of the Large Hadron Collider (LHC) at CERN. The detector output voltage is digitized with a 24-bit ADC at the rate of the reference signals. The resulting samples are processed in the front-end FPGA and transmitted to the control system using an Ethernet data stream. After a detailed description of the differential phase detector its performance is demonstrated with laboratory measurements. The results show tha...

  8. Tumour size is the only predictive factor of distant recurrence after pathological complete response to neoadjuvant chemotherapy in patients with large operable or locally advanced breast cancers: a sub-study of EORTC 10994/BIG 1-00 phase III trial.

    Science.gov (United States)

    Fei, F; Messina, C; Slaets, L; Chakiba, C; Cameron, D; Bogaerts, J; Bonnefoi, H

    2015-02-01

    Although achieving a pathological complete response (pCR) after neoadjuvant chemotherapy (NACT) in breast cancer predicts a better outcome, some patients still relapse. The objectives of this study were to describe the types of events in this group of patients and to identify predictive factors for relapse. Patients with large operable or locally advanced breast cancers (T4d tumours were excluded) were randomised to receive either six cycles of anthracycline-based chemotherapy or three cycles of docetaxel followed by three cycles of eprirubicin/docetaxel. pCR was defined as no evidence of residual invasive cancer (or very few scattered tumour cells) in the primary tumour and axillary lymph nodes at surgery. Two Cox regression analyses were performed to identify predictive factors of relapse: one for recurrence-free interval (RFI) and one for distant recurrence-free interval (DRFI). Out of 283 eligible patients who achieved a pCR, 40 (14.1%) and 28 (9.9%) presented an event of interest for the RFI and DRFI analyses, respectively. Five-year RFI, DRFI and overall survival (OS) were 85.3% (95% confidence interval (CI), 80.1-89.3), 89.6% (95% CI, 85.0-92.9) and 91.9% (95% CI, 87.2-94.9), respectively. No predictors for RFI after pCR were identified. For DRFI, tumour size was the only predictor: Hazard ratio (HR) T3 versus T1-2=3.62 (95% CI, 1.66-7.89); HR T4 versus T1-2: HR, 2.80 (95% CI, 0.62-12.64) p=0.0048. In this study, clinical tumour size emerged as the only predictor for DRFI after pCR, with T3 and T4 tumours having an increased risk for distant recurrence compared to T1-2 tumours. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Interacting spins in a cavity: Finite-size effects and symmetry-breaking dynamics

    DEFF Research Database (Denmark)

    Gammelmark, Søren; Mølmer, Klaus

    2012-01-01

    , and for small chains, we find significant and nontrivial finite-size effects. Below the first-order phase transition, even quite large spin chains of 30–40 spins give rise to a mean photon number and number fluctuations significantly above the mean-field vacuum result. Near the second-order phase critical point......, our calculations reveal photon number fluctuations that grow beyond Poisson statistics with the size of the spin chain. We simulate the stochastic evolution of the system when the cavity output field is subject to homodyne detection. For an initial state close to the first-order phase...

  10. Particle size distribution of selected electronic nicotine delivery system products.

    Science.gov (United States)

    Oldham, Michael J; Zhang, Jingjie; Rusyniak, Mark J; Kane, David B; Gardner, William P

    2018-01-31

    Dosimetry models can be used to predict the dose of inhaled material, but they require several parameters including particle size distribution. The reported particle size distributions for aerosols from electronic nicotine delivery system (ENDS) products vary widely and don't always identify a specific product. A low-flow cascade impactor was used to determine the particle size distribution [mass median aerodynamic diameter (MMAD); geometric standard deviation (GSD)] from 20 different cartridge based ENDS products. To assess losses and vapor phase amount, collection efficiency of the system was measured by comparing the collected mass in the impactor to the difference in ENDS product mass. The levels of nicotine, glycerin, propylene glycol, water, and menthol in the formulations of each product were also measured. Regardless of the ENDS product formulation, the MMAD of all tested products was similar and ranged from 0.9 to 1.2 μm with a GSD ranging from 1.7 to 2.2. There was no consistent pattern of change in the MMAD and GSD as a function of number of puffs (cartridge life). The collection efficiency indicated that 9%-26% of the generated mass was deposited in the collection system or was in the vapor phase. The particle size distribution data are suitable for use in aerosol dosimetry programs. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Simple size control of spherical titania naoparticles with KCI

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Joo Hyun; Um, Ji Hyun; Park, Yun Ji; Sung, Yung Eun; Lee, Jin Kyu [Seoul National University, Seoul (Korea, Republic of)

    2015-04-15

    Titania nanoparticles (TNPs) that are already in widespread used in our daily lives as white pigments and sunscreen materials have attracted much attention for their possible applications in various fields, such as photonic band materials, gas sensing, solar cells, batteries, and photocatalysts. We systemically investigated the factors controlling the size of TNPs in the presence of KCl. The amount of titanium precursor, the concentration of KCl, the reaction temperature, and the polarity of the solvent were all shown to affect the kinetics of the hydrolysis/condensation and to dictate the resulting particle size. We also showed that the prepared TNPs at room temperature could be effectively phase-transformed to anatase nanocrystals, which exhibited very effective photocatalytic activity comparable to that of commercialized TiO{sub 2} photocatalysts. We believed that this simple preparation method, which allows for size control of our particles, along with easy surface modification could expand the usage of TNPs to various applications.

  12. Superfluid phases of $^3$He in nano-scale channels

    OpenAIRE

    Wiman, J. J.; Sauls, J. A.

    2015-01-01

    Confinement of superfluid $^3$He on length scales comparable to the radial size of the p-wave Cooper pairs can greatly alter the phase diagram by stabilizing broken symmetry phases not observed in bulk $^3$He. We consider superfluid $^3$He confined within long cylindrical channels of radius $100\\mbox{ nm}$, and report new theoretical predictions for the equilibrium superfluid phases under strong confinement. The results are based on the strong-coupling formulation of Ginzburg-Landau theory wi...

  13. Structural Rheology of the Smectic Phase

    Directory of Open Access Journals (Sweden)

    Shuji Fujii

    2014-07-01

    Full Text Available In this review article, we discuss the rheological properties of the thermotropic smectic liquid crystal 8CB with focal conic domains (FCDs from the viewpoint of structural rheology. It is known that the unbinding of the dislocation loops in the smectic phase drives the smectic-nematic transition. Here we discuss how the unbinding of the dislocation loops affects the evolution of the FCD size, linear and nonlinear rheological behaviors of the smectic phase. By studying the FCD formation from the perpendicularly oriented smectic layers, we also argue that dislocations play a key role in the structural development in layered systems. Furthermore, similarities in the rheological behavior between the FCDs in the smectic phase and the onion structures in the lyotropic lamellar phase suggest that these systems share a common physical origin for the elasticity.

  14. Phase-Shifting Zernike Interferometer Wavefront Sensor

    Science.gov (United States)

    Wallace, J. Kent; Rao, Shanti; Jensen-Clemb, Rebecca M.; Serabyn, Gene

    2011-01-01

    The canonical Zernike phase-contrast technique1,2,3,4 transforms a phase object in one plane into an intensity object in the conjugate plane. This is done by applying a static pi/2 phase shift to the central core (approx. lambda/D) of the PSF which is intermediate between the input and output planes. Here we present a new architecture for this sensor. First, the optical system is simple and all reflective. Second, the phase shift in the central core of the PSF is dynamic and or arbitrary size. This common-path, all-reflective design makes it minimally sensitive to vibration, polarization and wavelength. We review the theory of operation, describe the optical system, summarize numerical simulations and sensitivities and review results from a laboratory demonstration of this novel instrument

  15. Cirrus Parcel Model Comparison Phase 2

    Science.gov (United States)

    Lin, Ruei-Fong; Starr, David OC.; DeMott, Paul J.; Cotton, Richard; Jensen, Eric; Kaercher, Bernd; Liu, Xiaohong

    2002-01-01

    The Cirrus Parcel Model Comparison (CPMC) project, a project of the GEWEX Cloud System Study Working Group on cirrus clouds (GCSS WG2), is an international effort to advance our knowledge of numerical simulations of cirrus cloud initiation. This project was done in two phases. In Phase 1 of CPMC, the critical components determining the predicted cloud microphysical properties were identified using parcel models in which the aerosol and ice crystal size distributions are explicitly resolved, the formulation of the homogeneous freezing of aqueous solution droplets, especially the gradient of nucleation rate with respect to solution concentration; aerosol growth modeling; and the mass accommodation coefficient of water vapor on ice surface (the deposition coefficient). In Phase 1, all simulations were conducted using a given background aerosol distribution. To complete the comparison study, participant model responses to a range of background aerosol distributions are investigated in Phase 2.

  16. Geometric phases in physics

    CERN Document Server

    Shapere, Alfred D

    1989-01-01

    During the last few years, considerable interest has been focused on the phase that waves accumulate when the equations governing the waves vary slowly. The recent flurry of activity was set off by a paper by Michael Berry, where it was found that the adiabatic evolution of energy eigenfunctions in quantum mechanics contains a phase of geometric origin (now known as 'Berry's phase') in addition to the usual dynamical phase derived from Schrödinger's equation. This observation, though basically elementary, seems to be quite profound. Phases with similar mathematical origins have been identified

  17. Solution phase combinatorial chemistry.

    Science.gov (United States)

    Merritt, A T

    1998-06-01

    Combinatorial chemistry and parallel array synthesis techniques are now used extensively in the drug discovery process. Although published literature has been dominated by solid phase chemistry approaches, the use of solution phase techniques has also been widely explored. This review considers the advantages and disadvantages of choosing solution phase approaches in the various stages of drug discovery and optimisation, and assesses the practical issues related to these approaches. The uses of standard solution chemistry, the related liquid phase approach, and of supported materials to enhance solution phase chemistry are all illustrated by a comprehensive review of the published literature over the past three years.

  18. Single-Phase PLLs

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2017-01-01

    Single-phase phase-locked loops (PLLs) are popular for the synchronization and control of single-phase gridconnected converters. They are also widely used for monitoring and diagnostic purposes in the power and energy areas. In recent years, a large number of single-phase PLLs with different stru......-PLLs). The members of each category are then described and their pros and cons are discussed. This work provides a deep insight into characteristics of different single-phase PLLs and, therefore, can be considered as a reference for researchers and engineers....

  19. Methodology for optimally sized centrifugal partition chromatography columns.

    Science.gov (United States)

    Chollet, Sébastien; Marchal, Luc; Jérémy Meucci; Renault, Jean-Hugues; Legrand, Jack; Foucault, Alain

    2015-04-03

    Centrifugal Partition Chromatography (CPC) is a separation process based on the partitioning of solutes between two partially miscible liquid phases. There is no solid support for the stationary phase. The centrifugal acceleration is responsible for both stationary phase retention and mobile phase dispersion. CPC is thus a process based on liquid-liquid mass transfer. The separation efficiency is mainly influenced by the hydrodynamics of the phases in each cell of the column. Thanks to a visualization system, called "Visual CPC", it was observed that the mobile phase can flow through the stationary phase as a sheet, or a spray. Hydrodynamics, which directly governs the instrument efficiency, is directly affected during scale changes, and non-linear phenomena prevent the successful achievement of mastered geometrical scale changes. In this work, a methodology for CPC column sizing is proposed, based on the characterization of the efficiency of advanced cell shapes, taking into account the hydrodynamics. Knowledge about relationship between stationary phase volume, cell efficiency and separation resolution in CPC allowed calculating the optimum cell number for laboratory and industrial scale CPC application. The methodology is highlighted with results on five different geometries from 25 to 5000 mL, for two applications: the separation of alkylbenzene by partitioning with heptane/methanol/water biphasic system; and the separation of peptides by partitioning with n-butanol/acetic acid/water (4/1/5) biphasic system. With this approach, it is possible to predict the optimal CPC column length leading to highest productivity. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Size Estimates in Inverse Problems

    KAUST Repository

    Di Cristo, Michele

    2014-01-06

    Detection of inclusions or obstacles inside a body by boundary measurements is an inverse problems very useful in practical applications. When only finite numbers of measurements are available, we try to detect some information on the embedded object such as its size. In this talk we review some recent results on several inverse problems. The idea is to provide constructive upper and lower estimates of the area/volume of the unknown defect in terms of a quantity related to the work that can be expressed with the available boundary data.

  1. Generalized phase contrast:

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Palima, Darwin

    Generalized Phase Contrast elevates the phase contrast technique not only to improve phase imaging but also to cross over and interface with diverse and seemingly disparate fields of contemporary optics and photonics. This book presents a comprehensive introduction to the Generalized Phase Contrast...... (GPC) method including an overview of the range of current and potential applications of GPC in wavefront sensing and phase imaging, structured laser illumination and image projection, optical trapping and manipulation, and optical encryption and decryption. The GPC method goes further than...... the restrictive assumptions of conventional Zernike phase contrast analysis and achieves an expanded range of validity beyond weak phase perturbations. The generalized analysis yields design criteria for tuning experimental parameters to achieve optimal performance in terms of accuracy, fidelity and light...

  2. Generalized Phase Contrast

    CERN Document Server

    Glückstad, Jesper

    2009-01-01

    Generalized Phase Contrast elevates the phase contrast technique not only to improve phase imaging but also to cross over and interface with diverse and seemingly disparate fields of contemporary optics and photonics. This book presents a comprehensive introduction to the Generalized Phase Contrast (GPC) method including an overview of the range of current and potential applications of GPC in wavefront sensing and phase imaging, structured laser illumination and image projection, optical trapping and manipulation, and optical encryption and decryption. The GPC method goes further than the restrictive assumptions of conventional Zernike phase contrast analysis and achieves an expanded range of validity beyond weak phase perturbations. The generalized analysis yields design criteria for tuning experimental parameters to achieve optimal performance in terms of accuracy, fidelity and light efficiency. Optimization can address practical issues, such as finding an optimal spatial filter for the chosen application, ...

  3. Measurement of the defect size by shearography or other interferometric techniques

    Science.gov (United States)

    Michel, Fabrice; Renotte, Yvon L.; Habraken, Serge

    2012-03-01

    Shearography is an interferometric technique suitable for detecting defects because they yield singular fringes and high phase values in wrapped and unwrapped phasemaps, respectively. We propose a methodology that leads to the defect size from unwrapped phasemap by extracting the size of the high phase values area. The area size is evaluated, thanks to a wavelet transform algorithm that enables the location of its borders. The performances of the methodology and of the algorithm have been tested by applying them on a defect where the size is known. An error less than 1.5% root mean square was reached. Our approach is independent of the shearing amount and of the phase profile, and it can be extended for other interferometric techniques.

  4. NON-COHESIVE SOILS’ COMPRESSIBILITY AND UNEVEN GRAIN-SIZE DISTRIBUTION RELATION

    Directory of Open Access Journals (Sweden)

    Anatoliy Mirnyy

    2016-03-01

    Full Text Available This paper presents the results of laboratory investigation of soil compression phases with consideration of various granulometric composition. Materials and Methods Experimental soil box with microscale video recording for compression phases studies is described. Photo and video materials showing the differences of microscale particle movements were obtained for non-cohesive soils with different grain-size distribution. Results The analysis of the compression tests results and elastic and plastic deformations separation allows identifying each compression phase. It is shown, that soil density is correlating with deformability parameters only for the same grain-size distribution. Basing on the test results the authors suggest that compaction ratio is not sufficient for deformability estimating without grain-size distribution taken into account. Discussion and Conclusions Considering grain-size distribution allows refining technological requirements for artificial soil structures, backfills, and sand beds. Further studies could be used for developing standard documents, SP45.13330.2012 in particular.

  5. Hard-phase engineering in hard/soft nanocomposite magnets

    Science.gov (United States)

    Poudyal, Narayan; Rong, Chuanbing; Vuong Nguyen, Van; Liu, J. Ping

    2014-03-01

    Bulk SmCo/Fe(Co) based hard/soft nanocomposite magnets with different hard phases (1:5, 2:17, 2:7 and 1:3 types) were fabricated by high-energy ball-milling followed by a warm compaction process. Microstructural studies revealed a homogeneous distribution of bcc-Fe(Co) phase in the matrix of hard magnetic Sm-Co phase with grain size ⩽20 nm after severe plastic deformation and compaction. The small grain size leads to effective inter-phase exchange coupling as shown by the single-phase-like demagnetization behavior with enhanced remanence and energy product. Among the different hard phases investigated, it was found that the Sm2Co7-based nanocomposites can incorporate a higher soft phase content, and thus a larger reduction in rare-earth content compared with the 2:17, 1:5 and 1:3 phase-based nanocomposite with similar properties. (BH)max up to 17.6 MGOe was obtained for isotropic Sm2Co7/FeCo nanocomposite magnets with 40 wt% of the soft phase which is about 300% higher than the single-phase counterpart prepared under the same conditions. The results show that hard-phase engineering in nanocomposite magnets is an alternative approach to fabrication of high-strength nanocomposite magnets with reduced rare-earth content.

  6. Rigorous 3D simulation of phase defects in alternating phase-shifting masks

    Science.gov (United States)

    Pistor, Thomas V.

    2002-03-01

    A study of both the printability and inspectability of phase defects in alternating phase-shifting masks is made using rigorous FDTD simulation of mask topography and vector-based models for optical imaging that account for the angular dependence of the mask scattering coefficients and high numerical aperture effects. Aerial images inside the photoresist are calculated through focus under typical 193nm stepper imaging conditions in order to assess the effects of size, phase, location and shape on the printability of phase bump defects. Defects located adjacent to the vertical sidewalls of the phase shifter are found to affect CD more than defects located in the center of the phase shifter. Defect shape does not appear to be a strong factor in printability. Aerial images and difference signals for various defects under mask transmission-imaging inspection conditions are calculated. A study of illumination pupil effects in mask inspection is presented. Defect visibility when varying defect size and position is investigated. Defects close to the phase shifter vertical sidewall are less visible. Defects are observed to be more visible when the mask is defocused. An investigation of illumination effects show that coherent systems can see defects better than incoherent systems, while certain incident plane waves are found to 'see' a particular defect better than others.

  7. Distinct Chiral Nematic Self-Assembling Behavior Caused by Different Size-Unified Cellulose Nanocrystals via a Multistage Separation.

    Science.gov (United States)

    Hu, Yang; Abidi, Noureddine

    2016-09-27

    Cellulose nanocrystals (CNCs) are perfect rodlike nanofibers that can self-assemble and form a chiral nematic phase. We found that different self-assembling morphologies could be formed by different size-unified CNCs. This study reported a facile and new approach of fractionating raw (unseparated) CNCs in a wide particle size distribution (9-1700 nm) into a series of narrower size ranges to obtain size-unified CNCs via a well-designed multistage separation process composed of layered filter membranes with different pore size cutoffs followed by a fast pressurized filtration. The smaller size-unified CNCs readily self-assembled into polish chiral nematic phases with larger pitch value as compared to larger size-unified CNCs. Such a distinction among different chiral nematic phases and pitch values as functions of size was addressed by a mathematical evaluation, which suggested that the reduced volume fraction of the anisotropic phase as a function of both increased ionic strength and reduced crystallinity of rigid-rod-like CNCs is a critical factor. In addition, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction results revealed that different size-unified CNCs exhibited particular thermal stabilities and crystallinities even though their chemical and crystalline structures remained unchanged. The discrepancies in physicochemical characteristics and self-assembling chiral nematic behavior among different size-unified CNCs may benefit the specific functionalization of cellulose materials using size-unified fibers instead of raw CNCs containing mixed small and large fibers.

  8. Quantum phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Sachdev, S. [Yale University, New Haven, CT (United States)

    1999-04-01

    Phase transitions are normally associated with changes of temperature but a new type of transition - caused by quantum fluctuations near absolute zero - is possible, and can tell us more about the properties of a wide range of systems in condensed-matter physics. Nature abounds with phase transitions. The boiling and freezing of water are everyday examples of phase transitions, as are more exotic processes such as superconductivity and superfluidity. The universe itself is thought to have passed through several phase transitions as the high-temperature plasma formed by the big bang cooled to form the world as we know it today. Phase transitions are traditionally classified as first or second order. In first-order transitions the two phases co-exist at the transition temperature - e.g. ice and water at 0 deg., or water and steam at 100 deg. In second-order transitions the two phases do not co-exist. In the last decade, attention has focused on phase transitions that are qualitatively different from the examples noted above: these are quantum phase transitions and they occur only at the absolute zero of temperature. The transition takes place atthe ''quantum critical'' value of some other parameter such as pressure, composition or magnetic field strength. A quantum phase transition takes place when co-operative ordering of the system disappears, but this loss of order is driven solely by the quantum fluctuations demanded by Heisenberg's uncertainty principle. The physical properties of these quantum fluctuations are quite distinct from those of the thermal fluctuations responsible for traditional, finite-temperature phase transitions. In particular, the quantum system is described by a complex-valued wavefunction, and the dynamics of its phase near the quantum critical point requires novel theories that have no analogue in the traditional framework of phase transitions. In this article the author describes the history of quantum phase

  9. 7 CFR 51.1402 - Size classification.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Size classification. 51.1402 Section 51.1402... STANDARDS) United States Standards for Grades of Pecans in the Shell 1 Size Classification § 51.1402 Size classification. Size of pecans may be specified in connection with the grade in accordance with one of the...

  10. 7 CFR 51.1903 - Size classification.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Size classification. 51.1903 Section 51.1903... STANDARDS) United States Consumer Standards for Fresh Tomatoes Size and Maturity Classification § 51.1903 Size classification. The following terms may be used for describing the size of the tomatoes in any lot...

  11. Four equivalent lot-sizing models

    NARCIS (Netherlands)

    W. van den Heuvel (Wilco); A.P.M. Wagelmans (Albert)

    2007-01-01

    textabstractWe study the following lot-sizing models that recently appeared in the literature: a lot-sizing model with a remanufacturing option, a lot-sizing model with production time windows, and a lot-sizing model with cumulative capacities. We show the equivalence of these models with a

  12. Probing exoplanet clouds with optical phase curves.

    Science.gov (United States)

    Muñoz, Antonio García; Isaak, Kate G

    2015-11-03

    Kepler-7b is to date the only exoplanet for which clouds have been inferred from the optical phase curve--from visible-wavelength whole-disk brightness measurements as a function of orbital phase. Added to this, the fact that the phase curve appears dominated by reflected starlight makes this close-in giant planet a unique study case. Here we investigate the information on coverage and optical properties of the planet clouds contained in the measured phase curve. We generate cloud maps of Kepler-7b and use a multiple-scattering approach to create synthetic phase curves, thus connecting postulated clouds with measurements. We show that optical phase curves can help constrain the composition and size of the cloud particles. Indeed, model fitting for Kepler-7b requires poorly absorbing particles that scatter with low-to-moderate anisotropic efficiency, conclusions consistent with condensates of silicates, perovskite, and silica of submicron radii. We also show that we are limited in our ability to pin down the extent and location of the clouds. These considerations are relevant to the interpretation of optical phase curves with general circulation models. Finally, we estimate that the spherical albedo of Kepler-7b over the Kepler passband is in the range 0.4-0.5.

  13. Population Genetics with Fluctuating Population Sizes

    Science.gov (United States)

    Chotibut, Thiparat; Nelson, David R.

    2017-05-01

    Standard neutral population genetics theory with a strictly fixed population size has important limitations. An alternative model that allows independently fluctuating population sizes and reproduces the standard neutral evolution is reviewed. We then study a situation such that the competing species are neutral at the equilibrium population size but population size fluctuations nevertheless favor fixation of one species over the other. In this case, a separation of timescales emerges naturally and allows adiabatic elimination of a fast population size variable to deduce the fluctuation-induced selection dynamics near the equilibrium population size. The results highlight the incompleteness of the standard population genetics with a strictly fixed population size.

  14. Metamagnetic Anomalies near Dynamic Phase Transitions.

    Science.gov (United States)

    Riego, P; Vavassori, P; Berger, A

    2017-03-17

    We report the existence of anomalous metamagnetic fluctuations in the vicinity of the dynamic phase transition (DPT) that do not occur for the corresponding thermodynamic behavior of simple ferromagnets. Our results demonstrate that key characteristics associated with the DPT are qualitatively different from conventional thermodynamic phase transitions. We also provide evidence that these differences are tunable by showing that the presence of metamagnetic fluctuations and the size of the critical scaling regime depend strongly on the amplitude of the oscillating field that is driving the DPT in the first place.

  15. The "child size medicines" concept

    DEFF Research Database (Denmark)

    Nsabagasani, Xavier; Okeng, Jasper Ogwal; Mbonye, Anthony

    2015-01-01

    Background In 2007, the World Health Organization (WHO) launched the ‘make medicines child size’ (MMCS) campaign by urging countries to prioritize procurement of medicines with appropriate strengths for children’s age and weight and, in child-friendly formulations of rectal and flexible oral solid...... of policy provisions for the MMCS recommendations. Results For most medicines for the selected diseases, appropriate strength for children’s age and weight was addressed especially in the EMHSLU 2012. However, policy documents neither referred to ‘child size medicines’ concept nor provided for flexible oral...... health policy documents reflected limited adherence to the MMCS recommendations. This and failure to use evidence based medicines may result into treatment failure and or death. A revision of the current policies and guidelines to better reflect ‘child size’, child appropriate and evidence based...

  16. Phosphatidylcholine: cholesterol phase diagrams.

    Science.gov (United States)

    Thewalt, J L; Bloom, M

    1992-10-01

    Two mono-cis-unsaturated phosphatidylcholine (PC) lipid molecules, having very different gel-liquid crystalline phase transition temperatures as a consequence of the relative positions of the double bond, exhibit PC:cholesterol phase diagrams that are very similar to each other and to that obtained previously for a fully saturated PC:cholesterol mixture (Vist, M. R., and J. H. Davis. 1990. Biochemistry 29:451-464). This leads to the conjecture that PC:cholesterol membrane phase diagrams have a universal form which is relatively independent of the precise chemical structure of the PC molecule. One feature of this phase diagram is the observation over a wide temperature range of a fluid but highly conformationally ordered phase at bilayer concentrations of more than approximately 25 mol% cholesterol. This ;liquid ordered' phase is postulated to be the relevant physical state for many biological membranes, such as the plasma membrane of eukaryotic cells, that contain substantial amounts of cholesterol or equivalent sterols.

  17. Gymnastics in Phase Space

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Alexander Wu; /SLAC

    2012-03-01

    As accelerator technology advances, the requirements on accelerator beam quality become increasingly demanding. Facing these new demands, the topic of phase space gymnastics is becoming a new focus of accelerator physics R&D. In a phase space gymnastics, the beam's phase space distribution is manipulated and precision tailored to meet the required beam qualities. On the other hand, all realization of such gymnastics will have to obey accelerator physics principles as well as technological limitations. Recent examples of phase space gymnastics include Emittance exchanges, Phase space exchanges, Emittance partitioning, Seeded FELs and Microbunched beams. The emittance related topics of this list are reviewed in this report. The accelerator physics basis, the optics design principles that provide these phase space manipulations, and the possible applications of these gymnastics, are discussed. This fascinating new field promises to be a powerful tool of the future.

  18. Sample size formulae for the Bayesian continual reassessment method.

    Science.gov (United States)

    Cheung, Ying Kuen

    2013-01-01

    In the planning of a dose finding study, a primary design objective is to maintain high accuracy in terms of the probability of selecting the maximum tolerated dose. While numerous dose finding methods have been proposed in the literature, concrete guidance on sample size determination is lacking. With a motivation to provide quick and easy calculations during trial planning, we present closed form formulae for sample size determination associated with the use of the Bayesian continual reassessment method (CRM). We examine the sampling distribution of a nonparametric optimal design and exploit it as a proxy to empirically derive an accuracy index of the CRM using linear regression. We apply the formulae to determine the sample size of a phase I trial of PTEN-long in pancreatic cancer patients and demonstrate that the formulae give results very similar to simulation. The formulae are implemented by an R function 'getn' in the package 'dfcrm'. The results are developed for the Bayesian CRM and should be validated by simulation when used for other dose finding methods. The analytical formulae we propose give quick and accurate approximation of the required sample size for the CRM. The approach used to derive the formulae can be applied to obtain sample size formulae for other dose finding methods.

  19. Cosmological phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Kolb, E.W. [Fermi National Accelerator Lab., Batavia, IL (United States)]|[Chicago Univ., IL (United States)

    1993-10-01

    If modern ideas about the role of spontaneous symmetry breaking in fundamental physics are correct, then the Universe should have undergone a series of phase transitions early in its history. The study of cosmological phase transitions has become an important aspect of early-Universe cosmology. In this lecture I review some very recent work on three aspects of phase transitions: the electroweak transition, texture, and axions.

  20. Phase Holograms In PMMA

    Science.gov (United States)

    Maker, Paul D.; Muller, Richard E.

    1994-01-01

    Complex, computer-generated phase holograms written in thin films of poly(methyl methacrylate) (PMMA) by process of electron-beam exposure followed by chemical development. Spatial variations of phase delay in holograms quasi-continuous, as distinquished from stepwise as in binary phase holograms made by integrated-circuit fabrication. Holograms more precise than binary holograms. Greater continuity and precision results in decreased scattering loss and increased imaging efficiency.

  1. Thermodynamically Stable Blue Phases

    Science.gov (United States)

    Castles, F.; Morris, S. M.; Terentjev, E. M.; Coles, H. J.

    2010-04-01

    We show theoretically that flexoelectricity stabilizes blue phases in chiral liquid crystals. Induced internal polarization reduces the elastic energy cost of splay and bend deformations surrounding singular lines in the director field. The energy of regions of double twist is unchanged. This in turn reduces the free energy of the blue phase with respect to that of the chiral nematic phase, leading to stability over a wider temperature range. The theory explains the discovery of large temperature range blue phases in highly flexoelectric “bimesogenic” and “bent-core” materials, and predicts how this range may be increased further.

  2. Solid phase transformations II

    CERN Document Server

    Čermák, J

    2009-01-01

    This topical volume includes ten invited papers that cover selected areas of the field of solid phase transformations. The first two contributions represent a burgeoning branch; that of the computer simulation of physical phenomena. The following three articles deal with the thermodynamics of phase transformations as a basic theory for describing the phenomenology of phase changes in matter. The next paper describes the interconnections between structural stability and the electronic structure of phases. Two further articles are devoted to displacive transformations; a field where there are ma

  3. Dual phase evolution

    CERN Document Server

    Green, David G; Abbass, Hussein A

    2014-01-01

    This book explains how dual phase evolution operates in all these settings and provides a detailed treatment of the subject. The authors discuss the theoretical foundations for the theory, how it relates to other phase transition phenomena and its advantages in evolutionary computation and complex adaptive systems. The book provides methods and techniques to use this concept for problem solving. Dual phase evolution concerns systems that evolve via repeated phase shifts in the connectivity of their elements. It occurs in vast range of settings, including natural systems (species evolution, landscape ecology, geomorphology), socio-economic systems (social networks) and in artificial systems (annealing, evolutionary computing).

  4. Instantaneous phase shifting deflectometry.

    Science.gov (United States)

    Trumper, Isaac; Choi, Heejoo; Kim, Dae Wook

    2016-11-28

    An instantaneous phase shifting deflectometry measurement method is presented and implemented by measuring a time varying deformable mirror with an iPhone ® 6. The instantaneous method is based on multiplexing phase shifted fringe patterns with color, and decomposing them in x and y using Fourier techniques. Along with experimental data showing the capabilities of the instantaneous deflectometry system, a quantitative comparison with the Fourier transform profilometry method, which is a distinct phase measuring method from the phase shifting approach, is presented. Sources of error, nonlinear color-multiplexing induced error correction, and hardware limitations are discussed.

  5. Phase space and phase space transformations

    Energy Technology Data Exchange (ETDEWEB)

    Alefeld, B.

    1985-03-01

    For neutron scattering instrumentation Liouville's theorem plays a similar role as the second law of thermodynamics at least in the sense that from time to time 'ingenious' devices are discussed seriously, which are meant to increase the phase space density, these devices are analogous to a perpetuum mobile of the second kind.

  6. Self-assembled isoporous block copolymer membranes with tuned pore sizes

    KAUST Repository

    Yu, Haizhou

    2014-07-23

    The combination of nonsolvent-induced phase separation and the self-assembly of block copolymers can lead to asymmetric membranes with a thin highly ordered isoporous skin layer. The effective pore size of such membranes is usually larger than 15 nm. We reduced the pore size of these membranes by electroless gold deposition. We demonstrate that the pore sizes can be controlled precisely between 3 and 20 nm leading to a tunable sharp size discrimination in filtration processes. Besides fractionation of nanoparticles and biomaterials, controlled drug delivery is an attractive potential application. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Confined crystals of the smallest phase-change material.

    Science.gov (United States)

    Giusca, Cristina E; Stolojan, Vlad; Sloan, Jeremy; Börrnert, Felix; Shiozawa, Hidetsugu; Sader, Kasim; Rümmeli, Mark H; Büchner, Bernd; Silva, S Ravi P

    2013-09-11

    The demand for high-density memory in tandem with limitations imposed by the minimum feature size of current storage devices has created a need for new materials that can store information in smaller volumes than currently possible. Successfully employed in commercial optical data storage products, phase-change materials, that can reversibly and rapidly change from an amorphous phase to a crystalline phase when subject to heating or cooling have been identified for the development of the next generation electronic memories. There are limitations to the miniaturization of these devices due to current synthesis and theoretical considerations that place a lower limit of 2 nm on the minimum bit size, below which the material does not transform in the structural phase. We show here that by using carbon nanotubes of less than 2 nm diameter as templates phase-change nanowires confined to their smallest conceivable scale are obtained. Contrary to previous experimental evidence and theoretical expectations, the nanowires are found to crystallize at this scale and display amorphous-to-crystalline phase changes, fulfilling an important prerequisite of a memory element. We show evidence for the smallest phase-change material, extending thus the size limit to explore phase-change memory devices at extreme scales.

  8. Preliminary characterization of glass fiber sizing

    Energy Technology Data Exchange (ETDEWEB)

    Noergaard Petersen, H.; Almdal, K. [Technical Univ. of Denmark. DTU Nanotech, Kgs. Lyngby (Denmark); Kusano, Y.; Broendsted, P. [Technical Univ. of Denmark. DTU Wind Energy, Risoe Campus, Roskilde (Denmark)

    2013-09-01

    Glass fiber surfaces are treated with sizing during manufacturing. Sizing consists of several components, including a film former and a silane coupling agent that is important for adhesion between glass fibers and a matrix. Although the sizing highly affects the composite interface and thus the strength of the composites, little is known about the structure and chemistry of the sizing. A part of sizing was extracted by soxhlet extraction. The fibers were subsequently burned and some fibers were merely burned for analysis of glass fiber and sizing. The results showed that the analyzed fibers had amounts of bonded and physisorbed sizing similar to what has been presented in literature. An estimated sizing thickness was found to be approximately 100 nm. It is indicated that an epoxy-resin containing film former and a polyethylene oxide lubricant are present, yet no silanes or other sizing components were identified in the extractant. (Author)

  9. Monolithic phased arrays - Recent advances

    Science.gov (United States)

    Kinzel, Joseph A.

    1991-07-01

    Advances in monolithic phased array technology defined as a solid state array based on GaAs monolithic microwave integrated circuits are reviewed focusing on analytical and experimental work to improve array performance and reliability while reducing the cost. Monolithic array technology is equally applicable to communications and radar systems. In radar applications both transmit and receive functions at the elemental level require a transmit/receive module's physical size to be compatible with 1/2 wave length element spacing. For communication applications, separate aperture are used for transmit and receive to ensure sufficient isolation for full duplex operation. Radar transmitter chains are capable of operating with a saturated power output stage which helps to increase efficiency and minimize DC power. Communication systems place severe linearity constraints on the transmitters and receivers which requires the power amplifier to operate in an ultra-linear fashion.

  10. Omnidirectional antenna having constant phase

    Energy Technology Data Exchange (ETDEWEB)

    Sena, Matthew

    2017-04-04

    Various technologies presented herein relate to constructing and/or operating an antenna having an omnidirectional electrical field of constant phase. The antenna comprises an upper plate made up of multiple conductive rings, a lower ground-plane plate, a plurality of grounding posts, a conical feed, and a radio frequency (RF) feed connector. The upper plate has a multi-ring configuration comprising a large outer ring and several smaller rings of equal size located within the outer ring. The large outer ring and the four smaller rings have the same cross-section. The grounding posts ground the upper plate to the lower plate while maintaining a required spacing/parallelism therebetween.

  11. Phase stability in nanoscale material systems: extension from bulk phase diagrams

    Science.gov (United States)

    Bajaj, Saurabh; Haverty, Michael G.; Arróyave, Raymundo; Goddard Frsc, William A., III; Shankar, Sadasivan

    2015-05-01

    Phase diagrams of multi-component systems are critical for the development and engineering of material alloys for all technological applications. At nano dimensions, surfaces (and interfaces) play a significant role in changing equilibrium thermodynamics and phase stability. In this work, it is shown that these surfaces at small dimensions affect the relative equilibrium thermodynamics of the different phases. The CALPHAD approach for material surfaces (also termed ``nano-CALPHAD'') is employed to investigate these changes in three binary systems by calculating their phase diagrams at nano dimensions and comparing them with their bulk counterparts. The surface energy contribution, which is the dominant factor in causing these changes, is evaluated using the spherical particle approximation. It is first validated with the Au-Si system for which experimental data on phase stability of spherical nano-sized particles is available, and then extended to calculate phase diagrams of similarly sized particles of Ge-Si and Al-Cu. Additionally, the surface energies of the associated compounds are calculated using DFT, and integrated into the thermodynamic model of the respective binary systems. In this work we found changes in miscibilities, reaction compositions of about 5 at%, and solubility temperatures ranging from 100-200 K for particles of sizes 5 nm, indicating the importance of phase equilibrium analysis at nano dimensions.Phase diagrams of multi-component systems are critical for the development and engineering of material alloys for all technological applications. At nano dimensions, surfaces (and interfaces) play a significant role in changing equilibrium thermodynamics and phase stability. In this work, it is shown that these surfaces at small dimensions affect the relative equilibrium thermodynamics of the different phases. The CALPHAD approach for material surfaces (also termed ``nano-CALPHAD'') is employed to investigate these changes in three binary systems by

  12. A Quantitative Analysis of Growth and Size Regulation in Manduca sexta: The Physiological Basis of Variation in Size and Age at Metamorphosis.

    Directory of Open Access Journals (Sweden)

    Laura W Grunert

    Full Text Available Body size and development time are important life history traits because they are often highly correlated with fitness. Although the developmental mechanisms that control growth have been well studied, the mechanisms that control how a species-characteristic body size is achieved remain poorly understood. In insects adult body size is determined by the number of larval molts, the size increment at each molt, and the mechanism that determines during which instar larval growth will stop. Adult insects do not grow, so the size at which a larva stops growing determines adult body size. Here we develop a quantitative understanding of the kinetics of growth throughout larval life of Manduca sexta, under different conditions of nutrition and temperature, and for genetic strains with different adult body sizes. We show that the generally accepted view that the size increment at each molt is constant (Dyar's Rule is systematically violated: there is actually a progressive increase in the size increment from instar to instar that is independent of temperature. In addition, the mass-specific growth rate declines throughout the growth phase in a temperature-dependent manner. We show that growth within an instar follows a truncated Gompertz trajectory. The critical weight, which determines when in an instar a molt will occur, and the threshold size, which determines which instar is the last, are different in genetic strains with different adult body sizes. Under nutrient and temperature stress Manduca has a variable number of larval instars and we show that this is due to the fact that more molts at smaller increments are taken before threshold size is reached. We test whether the new insight into the kinetics of growth and size determination are sufficient to explain body size and development time through a mathematical model that incorporates our quantitative findings.

  13. Preliminary characterization of glass fiber sizing

    DEFF Research Database (Denmark)

    Petersen, Helga Nørgaard; Kusano, Yukihiro; Brøndsted, Povl

    2013-01-01

    Glass fiber surfaces are treated with sizing during manufacturing. Sizing consists of several components, including a film former and a silane coupling agent that is important for adhesion between glass fibers and a matrix. Although the sizing highly affects the composite interface and thus...... the strength of the composites, little is known about the structure and chemistry of the sizing. A part of sizing was extracted by soxhlet extraction. The fibers were subsequently burned and some fibers were merely burned for analysis of glass fiber and sizing. The results showed that the analyzed fibers had...

  14. Size Matters: FTIR Spectral Analysis of Apollo Regolith Samples Exhibits Grain Size Dependence.

    Science.gov (United States)

    Martin, Dayl; Joy, Katherine; Pernet-Fisher, John; Wogelius, Roy; Morlok, Andreas; Hiesinger, Harald

    2017-04-01

    sample dominates the bulk spectrum regardless of other physical properties. This has implications for surface analyses of other Solar System bodies where some mineral phases or components could be concentrated in a particular size fraction. For example, the anorthite grains in 67481,96 are dominantly >25 μm in size and therefore may not contribute proportionally to the bulk average spectrum (compared to the 25 microns and therefore does not represent a true average composition of the sample. Further investigation of how grain size and composition alters the average spectrum is required to fully understand infrared spectra of planetary surfaces. [1] - Hiesinger H., Helbert J., and MERTIS Co-I Team. (2010). The Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) for the BepiColombo Mission. Planetary and Space Science. 58, 144-165. [2] - NASA Lunar Sample Compendium. https://curator.jsc.nasa.gov/lunar/lsc/

  15. Phase retrieval for non-ideal in-line phase contrast x-ray imaging

    Science.gov (United States)

    Guo, Baikuan; Gao, Feng; Zhao, Huijuan; Zhang, Limin; Li, Jiao; Zhou, Zhongxing

    2017-02-01

    Phase contrast x-ray imaging techniques have shown the ability to overcome the weakness of the low sensitivity of conventional x-ray imaging. Among them, in-line phase contrast imaging, blessed with simplicity of arrangement, is deemed to be a promising technique in clinical application. To obtain quantitative information from in-line phase contrast images, numerous phase-retrieval techniques have been developed. The theories of these phase-retrieval techniques are mostly proposed on the basis of the ideal detector and the noise-free environment. However, in practice, both detector resolution and system noise would have impacts on the performance of these phase-retrieval methods. To assess the impacts of above-mentioned factors, we include the effects of Gaussian shaped detectors varying in the full width at half maximum (FWHM) and system noise at different levels into numerical simulations. The performance of the phase-retrieval methods under such conditions is evaluated by the root mean square error. The results demonstrate that an increase in the detector FWHM or noise level degrades the effect of phase retrieval, especially for objects in small size.

  16. Three-Phase PLLs

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Vasquez, Juan C.

    2017-01-01

    A phase-locked loop (PLL) is a nonlinear negativefeedback control system that synchronizes its output in frequency as well as in phase with its input. PLLs are now widely used for the synchronization of power electronics-based converters and also for monitoring and control purposes in different...

  17. the intermediate phase

    African Journals Online (AJOL)

    Research methods. The empirical investigation was divided into two phases: developmental and implementation. Method in the developmental phase. The action plan for the design of a new multiple-choice measuring instrument, proposed by Nunnally and Bernstein (1994), was considered appropriate for this study. First ...

  18. Optical phase conjugation

    CERN Document Server

    Fisher, Robert A

    1983-01-01

    This book appears at a time of intense activity in optical phase conjugation. We chose not to await the maturation of the field, but instead to provide this material in time to be useful in its development. We have tried very hard to elucidate and interrelate the various nonlinear phenomena which can be used for optical phase conjugation.

  19. UPVG phase 2 report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    The Utility PhotoVoltaic Group (UPVG), supported by member dues and a grant from the US Department of Energy, has as its mission the acceleration of the use of cost-effective small-scale and emerging large-scale applications of photovoltaics for the benefit of electric utilities and their customers. Formed in October, 1992, with the support of the American Public Power Association, Edison Electric Institute, and the National Rural Electric Cooperative Association, the UPVG currently has 90 members from all sectors of the electric utility industry. The UPVG`s efforts as conceived were divided into four phases: Phase 0--program plan; Phase 1--organization and strategy development; Phase 2--creating market assurance; and Phase 3--higher volume purchases. The Phase 0 effort developed the program plan and was completed early in 1993. The Phase 1 goal was to develop the necessary background information and analysis to lead to a decision as to which strategies could be undertaken by utilities to promote greater understanding of PV markets and achieve increased volumes of PV purchases. This report provides the details of the UPVG`s Phase 2 efforts to initiate TEAM-UP, its multiyear, 50-MW hardware initiative.

  20. Phase separation and the formation of cellular bodies

    Science.gov (United States)

    Xu, Bin; Broedersz, Chase P.; Meir, Yigal; Wingreen, Ned S.

    Cellular bodies in eukaryotic cells spontaneously assemble to form cellular compartments. Among other functions, these bodies carry out essential biochemical reactions. Cellular bodies form micron-sized structures, which, unlike canonical cell organelles, are not surrounded by membranes. A recent in vitro experiment has shown that phase separation of polymers in solution can explain the formation of cellular bodies. We constructed a lattice-polymer model to capture the essential mechanism leading to this phase separation. We used both analytical and numerical tools to predict the phase diagram of a system of two interacting polymers, including the concentration of each polymer type in the condensed and dilute phase.

  1. Size-energy relationships in ecological communities.

    Science.gov (United States)

    Sewall, Brent J; Freestone, Amy L; Hawes, Joseph E; Andriamanarina, Ernest

    2013-01-01

    Hypotheses that relate body size to energy use are of particular interest in community ecology and macroecology because of their potential to facilitate quantitative predictions about species interactions and to clarify complex ecological patterns. One prominent size-energy hypothesis, the energetic equivalence hypothesis, proposes that energy use from shared, limiting resources by populations or size classes of foragers will be independent of body size. Alternative hypotheses propose that energy use will increase with body size, decrease with body size, or peak at an intermediate body size. Despite extensive study, however, size-energy hypotheses remain controversial, due to a lack of directly-measured data on energy use, a tendency to confound distinct scaling relationships, and insufficient attention to the ecological contexts in which predicted relationships are likely to occur. Our goal, therefore, was to directly evaluate size-energy hypotheses while clarifying how results would differ with alternate methods and assumptions. We comprehensively tested size-energy hypotheses in a vertebrate frugivore guild in a tropical forest in Madagascar. Our test of size-energy hypotheses, which is the first to examine energy intake directly, was consistent with the energetic equivalence hypothesis. This finding corresponds with predictions of metabolic theory and models of energy distribution in ecological communities, which imply that body size does not confer an advantage in competition for energy among populations or size classes of foragers. This result was robust to different assumptions about energy regulation. Our results from direct energy measurement, however, contrasted with those obtained with conventional methods of indirect inference from size-density relationships, suggesting that size-density relationships do not provide an appropriate proxy for size-energy relationships as has commonly been assumed. Our research also provides insights into mechanisms

  2. Size-energy relationships in ecological communities.

    Directory of Open Access Journals (Sweden)

    Brent J Sewall

    Full Text Available Hypotheses that relate body size to energy use are of particular interest in community ecology and macroecology because of their potential to facilitate quantitative predictions about species interactions and to clarify complex ecological patterns. One prominent size-energy hypothesis, the energetic equivalence hypothesis, proposes that energy use from shared, limiting resources by populations or size classes of foragers will be independent of body size. Alternative hypotheses propose that energy use will increase with body size, decrease with body size, or peak at an intermediate body size. Despite extensive study, however, size-energy hypotheses remain controversial, due to a lack of directly-measured data on energy use, a tendency to confound distinct scaling relationships, and insufficient attention to the ecological contexts in which predicted relationships are likely to occur. Our goal, therefore, was to directly evaluate size-energy hypotheses while clarifying how results would differ with alternate methods and assumptions. We comprehensively tested size-energy hypotheses in a vertebrate frugivore guild in a tropical forest in Madagascar. Our test of size-energy hypotheses, which is the first to examine energy intake directly, was consistent with the energetic equivalence hypothesis. This finding corresponds with predictions of metabolic theory and models of energy distribution in ecological communities, which imply that body size does not confer an advantage in competition for energy among populations or size classes of foragers. This result was robust to different assumptions about energy regulation. Our results from direct energy measurement, however, contrasted with those obtained with conventional methods of indirect inference from size-density relationships, suggesting that size-density relationships do not provide an appropriate proxy for size-energy relationships as has commonly been assumed. Our research also provides insights

  3. Dilution of the cell cycle inhibitor Whi5 controls budding yeast cell size

    Science.gov (United States)

    Schmoller, Kurt M.; Turner, J.J.; Kõivomägi, M.; Skotheim, Jan M.

    2015-01-01

    Cell size fundamentally affects all biosynthetic processes by determining the scale of organelles and influencing surface transport1,2. Although extensive studies have identified many mutations affecting cell size, the molecular mechanisms underlying size control have remained elusive3. In budding yeast, size control occurs in G1 phase prior to Start, the point of irreversible commitment to cell division4,5. It was previously thought that activity of the G1 cyclin Cln3 increased with cell size to trigger Start by initiating the inhibition of the transcriptional inhibitor Whi56-8. However, while Cln3 concentration does modulate the rate at which cells pass Start, we found that its synthesis increases in proportion to cell size so that its total concentration is nearly constant during pre-Start G1. Rather than increasing Cln3 activity, we identify decreasing Whi5 activity — due to the dilution of Whi5 by cell growth — as a molecular mechanism through which cell size controls proliferation. Whi5 is synthesized in S/G2/M phases of the cell cycle in a largely size-independent manner. This results in smaller daughter cells being born with higher Whi5 concentrations that extend their pre-Start G1 phase. Thus, at its most fundamental level, budding yeast size control results from the differential scaling of Cln3 and Whi5 synthesis rates with cell size. More generally, our work shows that differential size-dependency of protein synthesis can provide an elegant mechanism to coordinate cellular functions with growth. PMID:26390151

  4. Dilution of the cell cycle inhibitor Whi5 controls budding-yeast cell size.

    Science.gov (United States)

    Schmoller, Kurt M; Turner, J J; Kõivomägi, M; Skotheim, Jan M

    2015-10-08

    Cell size fundamentally affects all biosynthetic processes by determining the scale of organelles and influencing surface transport. Although extensive studies have identified many mutations affecting cell size, the molecular mechanisms underlying size control have remained elusive. In the budding yeast Saccharomyces cerevisiae, size control occurs in G1 phase before Start, the point of irreversible commitment to cell division. It was previously thought that activity of the G1 cyclin Cln3 increased with cell size to trigger Start by initiating the inhibition of the transcriptional inhibitor Whi5 (refs 6-8). Here we show that although Cln3 concentration does modulate the rate at which cells pass Start, its synthesis increases in proportion to cell size so that its total concentration is nearly constant during pre-Start G1. Rather than increasing Cln3 activity, we identify decreasing Whi5 activity--due to the dilution of Whi5 by cell growth--as a molecular mechanism through which cell size controls proliferation. Whi5 is synthesized in S/G2/M phases of the cell cycle in a largely size-independent manner. This results in smaller daughter cells being born with higher Whi5 concentrations that extend their pre-Start G1 phase. Thus, at its most fundamental level, size control in budding yeast results from the differential scaling of Cln3 and Whi5 synthesis rates with cell size. More generally, our work shows that differential size-dependency of protein synthesis can provide an elegant mechanism to coordinate cellular functions with growth.

  5. SARCOPENIA: DESIGNING PHASE IIB TRIALS

    Science.gov (United States)

    CHUMLEA, WM.C.; CESARI, M.; EVANS, W.J.; FERRUCCI, L.; FIELDING, R.A.; PAHOR, M.; STUDENSKI, S.; VELLAS, B.

    2012-01-01

    Sarcopenia is the age-related involuntary loss of skeletal muscle mass and functionality that can lead to the development of disability, frailty and increased health care costs. The development of interventions aimed at preventing and/or treating sarcopenia is complex, requiring the adoption of assumptions and standards that are not well established scientifically or clinically. A number of investigators and clinicians (both from academia and industry) met in Rome (Italy) in 2009 to develop a consensus definition of sarcopenia. Subsequently, in Albuquerque (New Mexico, USA) in 2010, the same group met again to consider the complex issues necessary for designing Phase II clinical trials for sarcopenia. Current clinical trial data indicate that fat-free mass (FFM) parameters are responsive to physical activity/nutritional treatment modalities over short time periods, but pharmacological trials of sarcopenia have yet to show significant efficacy. In order to conduct a clinical trial within a reasonable time frame, groups that model or display accelerated aging and loss of FFM are necessary. Few studies have used acceptable designs for testing treatment effects, sample sizes or primary outcomes that could provide interpretable findings or effects across studies. Dual energy x ray absorptiometry (DXA) is the measure of choice for assessing FFM, but sufficient time is needed for changes to be detected accurately and reliably. A tool set that would allow clinical, basic and epidemiological research on sarcopenia to advance rapidly toward diagnosis and treatment phases should be those reflecting function and strength. PMID:21623466

  6. Quantum Phase Liquids-Fermionic Superfluid without Phase Coherence

    OpenAIRE

    Wu, Ya-Jie; Zhou, Jiang; Kou, Su-Peng

    2014-01-01

    We investigate the two dimensional generalized attractive Hubbard model in a bipartite lattice, and and a "quantum phase liquid" phase, in which the fermions are paired but don't have phase coherence at zero temperature, in analogy to quantum spin liquid phase. Then, two types of topological quantum phase liquids with a small external magnetic field-Z2 quantum phase liquids and chiral quantum phase liquids-are discussed.

  7. Controlling the Size of Autocorrelation Robust Tests

    OpenAIRE

    Pötscher, Benedikt M.; Preinerstorfer, David

    2016-01-01

    Autocorrelation robust tests are notorious for suffering from size distortions and power problems. We investigate under which conditions the size of autocorrelation robust tests can be controlled by an appropriate choice of critical value.

  8. Sizing of Microparticles from Angular Scattering Ratio

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Karamehmedovic, Mirza

    This technical note deals with light scattering measurements for sizing of micrometer-scale particles in a suspension.......This technical note deals with light scattering measurements for sizing of micrometer-scale particles in a suspension....

  9. Size-effect of germanium nanocrystals

    DEFF Research Database (Denmark)

    Ou, Haiyan; Ou, Yiyu; Liu, Chuan

    2011-01-01

    Different sizes of Ge nanocrystals embedded in a SiO2 matrix were formed by PECVD, and analyzed by TEM. Size effect of Ge nanocystals was demonstrated by Raman spectroscopy after excluding the thermal effect....

  10. The NGDC Seafloor Sediment Grain Size Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NGDC (now NCEI) Seafloor Sediment Grain Size Database contains particle size data for over 17,000 seafloor samples worldwide. The file was begun by NGDC in 1976...

  11. The size of the labor wards

    DEFF Research Database (Denmark)

    Milland, Maria; Christoffersen, Jens; Hedegaard, Morten

    2013-01-01

    To assess possible associations between the size of labor units and the frequency of approved obstetric claims.......To assess possible associations between the size of labor units and the frequency of approved obstetric claims....

  12. Phase transformations in Mo-doped FINEMETs

    Energy Technology Data Exchange (ETDEWEB)

    Silveyra, Josefina M., E-mail: jsilveyra@fi.uba.a [Lab. de Solidos Amorfos, INTECIN, FIUBA-CONICET, Paseo Colon 850, (C1063ACV) Buenos Aires (Argentina); Illekova, Emilia; Svec, Peter; Janickovic, Dusan [Institute of Physics SAS, Dubravska cesta 9, 845 11 Bratislava (Slovakia); Rosales-Rivera, Andres [Laboratorio de Magnetismo y Materiales Avanzados, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Colombia, Manizales (Colombia); Cremaschi, Victoria J. [Lab. de Solidos Amorfos, INTECIN, FIUBA-CONICET, Paseo Colon 850, (C1063ACV) Buenos Aires (Argentina)

    2010-06-15

    In this paper, the phase transformations occurring during the crystallization process of FINEMETs in which Nb has been gradually replaced by Mo have been studied by a variety of techniques including DSC, DTA, TGA, XRD and TEM. The thermal stability of the alloy was deteriorated as a consequence of Mo's smaller atomic size. The gradual replacement of Nb by Mo reduced the onset temperature of Fe-Si and of the borides. The Curie temperature of the amorphous phase slightly decreased from 594 K for x=0 to 587 K for x=3. The borides compounds Fe{sub 2}B and Fe{sub 23}B{sub 6} as well as the (Nb,Mo){sub 5}Si{sub 3} phase were found to precipitate in the second and third crystallization.

  13. Size-Energy Relationships in Ecological Communities

    OpenAIRE

    Brent J Sewall; Amy L. Freestone; Hawes, Joseph E.; Ernest Andriamanarina

    2013-01-01

    Hypotheses that relate body size to energy use are of particular interest in community ecology and macroecology because of their potential to facilitate quantitative predictions about species interactions and to clarify complex ecological patterns. One prominent size-energy hypothesis, the energetic equivalence hypothesis, proposes that energy use from shared, limiting resources by populations or size classes of foragers will be independent of body size. Alternative hypotheses propose that en...

  14. Technology for Obtaining Large Size Complex Oxide Crystals for Experiments on Muon-Electron Conversion Registration in High Energy Physics

    Directory of Open Access Journals (Sweden)

    Gerasymov, Ya.

    2014-11-01

    Full Text Available Technological approaches for qualitative large size scintillation crystals growing based on rare-earth silicates are proposed. A method of iridium crucibles charging using eutectic phase instead of a oxyorthosilicate was developed.

  15. The Wisdom of Class-Size Reduction

    Science.gov (United States)

    Graue, Elizabeth; Hatch, Kelly; Rao, Kalpana; Oen, Denise

    2007-01-01

    In this study, the authors explore the implementation of a statewide class-size reduction program in nine high-poverty schools. Through qualitative methods, they examined how schools used class-size reduction to change staffing patterns and instructional programs. Requiring changes in space allocation, class-size reduction was accomplished through…

  16. 7 CFR 51.2284 - Size classification.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Size classification. 51.2284 Section 51.2284... Size classification. The following classifications are provided to describe the size of any lot... shall conform to the requirements of the specified classification as defined below: (a) Halves. Lot...

  17. 7 CFR 51.344 - Size.

    Science.gov (United States)

    2010-01-01

    ... the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Standards for Grades of Apples for Processing Size § 51.344 Size. (a) The minimum and maximum sizes or range...

  18. Genetic size and growth in goats

    NARCIS (Netherlands)

    Ogink, N.W.M.

    1993-01-01

    Since the last century, many biologists have studied the effects of size differences between species on the rate of their metabolic processes. in 1980, Taylor published the genetic size-scaling theory which incorporated the existing knowledge on size effects, and introduced two formal

  19. School size effects: review and conceptual analysis

    NARCIS (Netherlands)

    Scheerens, Jaap; Hendriks, Maria A.; Luyten, Johannes W.; Luyten, Hans; Hendriks, Maria; Scheerens, Jaap

    2014-01-01

    In this chapter, a review of international review studies on school size effects is presented. Next, ingredients of a more contextualized and tentative causal mediation model of school size effects are discussed. The chapter is completed by a short overview of school size effects as found in

  20. Size effects in foams : Experiments and modeling

    NARCIS (Netherlands)

    Tekoglu, C.; Gibson, L. J.; Pardoen, T.; Onck, P. R.

    Mechanical properties of cellular solids depend on the ratio of the sample size to the cell size at length scales where the two are of the same order of magnitude. Considering that the cell size of many cellular solids used in engineering applications is between 1 and 10 mm, it is not uncommon to

  1. Is the myonuclear domain size fixed?

    NARCIS (Netherlands)

    van der Meer, S.F.T.; Jaspers, R. T.; Degens, H.

    2011-01-01

    It has been suggested that the number of myonuclei in a muscle fibre changes in proportion to the change in fibre size, resulting in a constant myonuclear domain size, defined as the cytoplasmic volume per myonucleus. The myonuclear domain size varies, however, between fibre types and is inversely

  2. Shock-wave micron-size diamond synthesis from fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Epanchintsev, O.G.; Zubchenko, A.S.; Kobelev, N.N. [Federal Scientific Center, Moscow (Russian Federation)] [and others

    1995-12-31

    Shock-wave synthesis of micron-size diamond is performed from fullerenes C{sub 60} -- C {sub 150} powders using the explosive compaction technique with plane shock-wave loading at different pressures in the range of 24-40 GPa. The compacts of different initial compositions consisted of diamond, fcc fullerite C{sub 60}, graphite and amorphous carbon. The most coarse diamond grains sized up to 6 {mu}n were formed at the shock pressure of 24 and 40 GPa in the compacts of initial powder mixture copper-5 mass.% fullerite and at shock pressure of 40 GPa in the compact of initial powder mixture copper - 10 mass.% fullerite. Shock-wave synthesis of diamond is performed without forming intermediate diamond-like phases, such as n-diamond and lonsdaleite (hexagonal diamond) in the final products.

  3. A quantitative method for clustering size distributions of elements

    Science.gov (United States)

    Dillner, Ann M.; Schauer, James J.; Christensen, William F.; Cass, Glen R.

    A quantitative method was developed to group similarly shaped size distributions of particle-phase elements in order to ascertain sources of the elements. This method was developed and applied using data from two sites in Houston, TX; one site surrounded by refineries, chemical plants and vehicular and commercial shipping traffic, and the other site, 25 miles inland surrounded by residences, light industrial facilities and vehicular traffic. Twenty-four hour size-segregated (0.056fluid catalytic cracking unit catalysts, fuel oil burning, a coal-fired power plant, and high-temperature metal working. The clustered elements were generally attributed to different sources at the two sites during each sampling day indicating the diversity of local sources that impact heavy metals concentrations in the region.

  4. Size dependence of magnetorheological properties of cobalt ferrite ferrofluid

    Energy Technology Data Exchange (ETDEWEB)

    Radhika, B.; Sahoo, Rasmita; Srinath, S., E-mail: srinath@uohyd.ac.in [School of Physics, University of Hyderabad, Hyderabad-500040 (India)

    2015-06-24

    Cobalt Ferrite nanoparticles were synthesized using co-precipitation method at reaction temperatures of 40°C and 80°C. X-Ray diffraction studies confirm cubic phase formation. The average crystallite sizes were found to be ∼30nm and ∼48nm for 40°C sample and 80°C sample respectively. Magnetic properties measured using vibrating sample magnetometer show higher coercivety and magnetization for sample prepared at 80°C. Magnetorheological properties of CoFe2O4 ferrofluids were measured and studied.

  5. Phase transformation and diffusion

    CERN Document Server

    Kale, G B; Dey, G K

    2008-01-01

    Given that the basic purpose of all research in materials science and technology is to tailor the properties of materials to suit specific applications, phase transformations are the natural key to the fine-tuning of the structural, mechanical and corrosion properties. A basic understanding of the kinetics and mechanisms of phase transformation is therefore of vital importance. Apart from a few cases involving crystallographic martensitic transformations, all phase transformations are mediated by diffusion. Thus, proper control and understanding of the process of diffusion during nucleation, g

  6. Martensitic phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Petry, W.; Neuhaus, J. [Techn. Universitaet Muenchen, Physik Department E13, Munich (Germany)

    1996-11-01

    Many elements transform from a high temperature bcc phase to a more dense packed temperature phase. The great majority of these transitions are of 1st order, displacive and reconstructive. The lattice potentials which govern these martensitic transitions can be probed by inelastic neutron scattering, thereby answering fundamental questions like : Will the transition be announced by dynamical or static fluctuations? What are the trajectories for the displacements needed for the transformation? Does the vibrational entropy stabilize the high temperature phase? Are the unusual transport properties in these materials related to their ability to transform? (author) 17 figs., 1 tab., 46 refs.

  7. Effect of geometric base roughness on size segregation

    Science.gov (United States)

    Jing, L.; Kwok, C. Y.; Leung, Y. F.; Sobral, Y. D.

    2017-06-01

    The geometric roughness at boundaries has a profound impact on the dynamics of granular flows. For a bumpy base made of fixed particles, two major factors have been separately studied in the literature, namely, the size and spatial distribution of base particles. A recent work (Jing et al. 2016) has proposed a roughness indicator Ra, which combines both factors for any arbitrary bumpy base comprising equally-sized spheres. It is shown in mono-disperse flows that as Ra increases, a transition occurs from slip (Ra 0.62) conditions. This work focuses on such a phase transition in bi-disperse flows, in which Ra can be a function of time. As size segregation takes place, large particles migrate away from the bottom, leading to a variation of size ratio between flow- and base-particles. As a result, base roughness Ra evolves with the progress of segregation. Consistent with the slip/non-slip transition in mono-disperse flows, basal sliding arises at low values of Ra and the development of segregation might be affected; when Ra increases to a certain level (Ra > 0.62), non-slip condition is respected. This work extends the validity of Ra to bi-disperse flows, which can be used to understand the geometric boundary effect during segregation.

  8. Gravity and Heater Size Effects on Pool Boiling Heat Transfer

    Science.gov (United States)

    Kim, Jungho; Raj, Rishi

    2014-01-01

    The current work is based on observations of boiling heat transfer over a continuous range of gravity levels between 0g to 1.8g and varying heater sizes with a fluorinert as the test liquid (FC-72/n-perfluorohexane). Variable gravity pool boiling heat transfer measurements over a wide range of gravity levels were made during parabolic flight campaigns as well as onboard the International Space Station. For large heaters and-or higher gravity conditions, buoyancy dominated boiling and heat transfer results were heater size independent. The power law coefficient for gravity in the heat transfer equation was found to be a function of wall temperature under these conditions. Under low gravity conditions and-or for smaller heaters, surface tension forces dominated and heat transfer results were heater size dependent. A pool boiling regime map differentiating buoyancy and surface tension dominated regimes was developed along with a unified framework that allowed for scaling of pool boiling over a wide range of gravity levels and heater sizes. The scaling laws developed in this study are expected to allow performance quantification of phase change based technologies under variable gravity environments eventually leading to their implementation in space based applications.

  9. Modeling the effects of size on patch dynamics of an inert tracer

    Directory of Open Access Journals (Sweden)

    P. Xiu

    2010-03-01

    Full Text Available Mesoscale iron enrichment experiments have revealed that additional iron affects the phytoplankton productivity and carbon cycle. However, the role of initial size of fertilized patch in determining the patch evolution is poorly quantified due to the limited observational capability and complex of physical processes. Using a three-dimensional ocean circulation model, we simulated different sizes of inert tracer patches that were only regulated by physical circulation and diffusion. Model results showed that during the first few days since release of inert tracer, the calculated dilution rate was found to be a linear function with time, which was sensitive to the initial patch size with steeper slope for smaller size patch. After the initial phase of rapid decay, the relationship between dilution rate and time became an exponential function, which was also size dependent. Therefore, larger initial size patches can usually last longer and ultimately affect biogeochemical processes much stronger than smaller patches.

  10. Size matters in the water uptake and hygroscopic growth of atmospherically relevant multicomponent aerosol particles.

    Science.gov (United States)

    Laskina, Olga; Morris, Holly S; Grandquist, Joshua R; Qin, Zhen; Stone, Elizabeth A; Tivanski, Alexei V; Grassian, Vicki H

    2015-05-14

    Understanding the interactions of water with atmospheric aerosols is crucial for determining the size, physical state, reactivity, and climate impacts of this important component of the Earth's atmosphere. Here we show that water uptake and hygroscopic growth of multicomponent, atmospherically relevant particles can be size dependent when comparing 100 nm versus ca. 6 μm sized particles. It was determined that particles composed of ammonium sulfate with succinic acid and of a mixture of chlorides typical of the marine environment show size-dependent hygroscopic behavior. Microscopic analysis of the distribution of components within the aerosol particles show that the size dependence is due to differences in the mixing state, that is, whether particles are homogeneously mixed or phase separated, for different sized particles. This morphology-dependent hygroscopicity has consequences for heterogeneous atmospheric chemistry as well as aerosol interactions with electromagnetic radiation and clouds.

  11. The Biosynthetic Basis of Cell Size Control.

    Science.gov (United States)

    Schmoller, Kurt M; Skotheim, Jan M

    2015-12-01

    Cell size is an important physiological trait that sets the scale of all biosynthetic processes. Although physiological studies have revealed that cells actively regulate their size, the molecular mechanisms underlying this regulation have remained unclear. Here we review recent progress in identifying the molecular mechanisms of cell size control. We focus on budding yeast, where cell growth dilutes a cell cycle inhibitor to couple growth and division. We discuss a new model for size control based on the titration of activator and inhibitor molecules whose synthesis rates are differentially dependent on cell size. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Do class size effects differ across grades?

    DEFF Research Database (Denmark)

    Nandrup, Anne Brink

    size cap that creates exogenous variation in class sizes. Significant (albeit modest) negative effects of class size increases are found for children on primary school levels. The effects on math abilities are statistically different across primary and secondary school. Larger classes do not affect......This paper contributes to the class size literature by analyzing whether short-run class size effects are constant across grade levels in compulsory school. Results are based on administrative data on all pupils enroled in Danish public schools. Identification is based on a government-imposed class...

  13. Transform extension for block-based hybrid video codec with decoupling transform sizes from prediction sizes and coding sizes

    Science.gov (United States)

    Chen, Jing; Li, Ge; Fan, Kui; Guo, Xiaoqiang

    2017-09-01

    In the block-based hybrid video coding framework, transform is applied to the residual signal resulting from intra/inter prediction. Thus in the most of video codecs, transform block (TB) size is equal to the prediction block (PB) size. To further improve coding efficiency, recent video coding techniques have supported decoupling transform and prediction sizes. By splitting one prediction block into small transform blocks, the Residual Quad-tree (RQT) structure attempts to search the best transform size. However, in the current RQT, the transform size cannot be larger than the size of prediction block. In this paper, we introduce a transform extension method by decoupling transform sizes from prediction sizes and coding sizes. In addition to getting the transform block within the current PB partition, we combine multiple adjacent PBs to form a larger TB and select best block size accordingly. According to our experiment on top of the newest reference software (ITM17.0) of MPEG Internet Video Coding (IVC) standard, consistent coding performance gains are obtained.

  14. Visuomotor Dissociation in Cerebral Scaling of Size.

    Science.gov (United States)

    Potgieser, Adriaan R E; de Jong, Bauke M

    2016-01-01

    Estimating size and distance is crucial in effective visuomotor control. The concept of an internal coordinate system implies that visual and motor size parameters are scaled onto a common template. To dissociate perceptual and motor components in such scaling, we performed an fMRI experiment in which 16 right-handed subjects copied geometric figures while the result of drawing remained out of sight. Either the size of the example figure varied while maintaining a constant size of drawing (visual incongruity) or the size of the examples remained constant while subjects were instructed to make changes in size (motor incongruity). These incongruent were compared to congruent conditions. Statistical Parametric Mapping (SPM8) revealed brain activations related to size incongruity in the dorsolateral prefrontal and inferior parietal cortex, pre-SMA / anterior cingulate and anterior insula, dominant in the right hemisphere. This pattern represented simultaneous use of a 'resized' virtual template and actual picture information requiring spatial working memory, early-stage attention shifting and inhibitory control. Activations were strongest in motor incongruity while right pre-dorsal premotor activation specifically occurred in this condition. Visual incongruity additionally relied on a ventral visual pathway. Left ventral premotor activation occurred in all variably sized drawing while constant visuomotor size, compared to congruent size variation, uniquely activated the lateral occipital cortex additional to superior parietal regions. These results highlight size as a fundamental parameter in both general hand movement and movement guided by objects perceived in the context of surrounding 3D space.

  15. Visuomotor Dissociation in Cerebral Scaling of Size

    Science.gov (United States)

    Potgieser, Adriaan R. E.; de Jong, Bauke M.

    2016-01-01

    Estimating size and distance is crucial in effective visuomotor control. The concept of an internal coordinate system implies that visual and motor size parameters are scaled onto a common template. To dissociate perceptual and motor components in such scaling, we performed an fMRI experiment in which 16 right-handed subjects copied geometric figures while the result of drawing remained out of sight. Either the size of the example figure varied while maintaining a constant size of drawing (visual incongruity) or the size of the examples remained constant while subjects were instructed to make changes in size (motor incongruity). These incongruent were compared to congruent conditions. Statistical Parametric Mapping (SPM8) revealed brain activations related to size incongruity in the dorsolateral prefrontal and inferior parietal cortex, pre-SMA / anterior cingulate and anterior insula, dominant in the right hemisphere. This pattern represented simultaneous use of a ‘resized’ virtual template and actual picture information requiring spatial working memory, early-stage attention shifting and inhibitory control. Activations were strongest in motor incongruity while right pre-dorsal premotor activation specifically occurred in this condition. Visual incongruity additionally relied on a ventral visual pathway. Left ventral premotor activation occurred in all variably sized drawing while constant visuomotor size, compared to congruent size variation, uniquely activated the lateral occipital cortex additional to superior parietal regions. These results highlight size as a fundamental parameter in both general hand movement and movement guided by objects perceived in the context of surrounding 3D space. PMID:26963705

  16. Visuomotor Dissociation in Cerebral Scaling of Size.

    Directory of Open Access Journals (Sweden)

    Adriaan R E Potgieser

    Full Text Available Estimating size and distance is crucial in effective visuomotor control. The concept of an internal coordinate system implies that visual and motor size parameters are scaled onto a common template. To dissociate perceptual and motor components in such scaling, we performed an fMRI experiment in which 16 right-handed subjects copied geometric figures while the result of drawing remained out of sight. Either the size of the example figure varied while maintaining a constant size of drawing (visual incongruity or the size of the examples remained constant while subjects were instructed to make changes in size (motor incongruity. These incongruent were compared to congruent conditions. Statistical Parametric Mapping (SPM8 revealed brain activations related to size incongruity in the dorsolateral prefrontal and inferior parietal cortex, pre-SMA / anterior cingulate and anterior insula, dominant in the right hemisphere. This pattern represented simultaneous use of a 'resized' virtual template and actual picture information requiring spatial working memory, early-stage attention shifting and inhibitory control. Activations were strongest in motor incongruity while right pre-dorsal premotor activation specifically occurred in this condition. Visual incongruity additionally relied on a ventral visual pathway. Left ventral premotor activation occurred in all variably sized drawing while constant visuomotor size, compared to congruent size variation, uniquely activated the lateral occipital cortex additional to superior parietal regions. These results highlight size as a fundamental parameter in both general hand movement and movement guided by objects perceived in the context of surrounding 3D space.

  17. In situ atomic-scale observation of melting point suppression in nanometer-sized gold particles

    Science.gov (United States)

    Lee, Junggoo; Lee, Joonho; Tanaka, Toshihiro; Mori, Hirotaro

    2009-11-01

    Phase stabilities of nanometer-sized materials are quite different from those of the corresponding bulk materials. Among the phase stabilities, melting point suppression is one of the most fundamentally important issues. In this work, real-time, atomic-scale direct observation of melting point suppression in nanometer-sized Au particles, along with simple size reduction, was carried out by means of in situ high resolution electron microscopy. Namely, it was confirmed in real space on an atomic scale that a solid-to-liquid transition occurred when the size of a particle, placed on a graphite substrate maintained at 1100 K, decreased to 5 nm during diminution. Furthermore, a monolayer-thick hole was formed on the substrate at the position of the liquid Au particle, probably due to carbon dissolution into the liquid Au particle.

  18. In situ atomic-scale observation of melting point suppression in nanometer-sized gold particles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Junggoo [Functional Materials Division, Korea Institute of Materials Science, 66 Sangnam-dong, Changwon, Kyungsangnam-Do 641-831 (Korea, Republic of); Lee, Joonho [Department of Materials Science and Engineering, Korea University, Anam-dong, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of); Tanaka, Toshihiro [Division of Materials and Manufacturing Science, Osaka University, 1-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Mori, Hirotaro, E-mail: jglee36@kims.re.k [Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, 7-1 Mihogaoka, Osaka 567-0047 (Japan)

    2009-11-25

    Phase stabilities of nanometer-sized materials are quite different from those of the corresponding bulk materials. Among the phase stabilities, melting point suppression is one of the most fundamentally important issues. In this work, real-time, atomic-scale direct observation of melting point suppression in nanometer-sized Au particles, along with simple size reduction, was carried out by means of in situ high resolution electron microscopy. Namely, it was confirmed in real space on an atomic scale that a solid-to-liquid transition occurred when the size of a particle, placed on a graphite substrate maintained at 1100 K, decreased to 5 nm during diminution. Furthermore, a monolayer-thick hole was formed on the substrate at the position of the liquid Au particle, probably due to carbon dissolution into the liquid Au particle.

  19. Determination of factors controlling the particle size in nanoemulsions using Artificial Neural Networks.

    Science.gov (United States)

    Amani, Amir; York, Peter; Chrystyn, Henry; Clark, Brian J; Do, Duong Q

    2008-09-02

    The purpose of this study was to use Artificial Neural Networks (ANNs) in identifying factors, in addition to surfactant and internal phase content, that influence the particle size of nanoemulsions. The phase diagram and rheometric characteristics of a nanoemulsion system containing polysorbate 80, ethanol, medium chain triglycerides and normal saline loaded with budesonide were investigated. The particle size of samples of various compositions prepared using different rates and amounts of applied energy was measured. Data, divided into training, test and validation sets, were modelled by ANNs. The developed model was assessed and found to be of high quality. The model was then used to explore the effect of composition and processing factors on particle size of the nanoemulsion preparation. The study demonstrates the potential of ANNs in identifying critical parameters controlling preparation for this system, with the total amount of applied energy during preparation found to be the dominant factor in controlling the final particle size.

  20. On the Size Distribution of Sand

    DEFF Research Database (Denmark)

    Sørensen, Michael

    2016-01-01

    by Bagnold and confirmed in numerous empirical studies. The model implies that the size distribution of a sand deposit is a logarithmic normal-inverse Gaussian (NIG) distribution, which is one of the generalized hyperbolic distributions. The model modifies a previous model, which implied a log-normal size-distribution......, variance and skewness of the log-size distribution to the physical parameters of the model. The results might be useful when comparing empirical size-distributions from different deposits. It is argued that size-distributions with the same general shape as the NIG-distributions can be obtained also when......A model is presented of the development of the size distribution of sand while it is transported from a source to a deposit. The model provides a possible explanation of the log-hyperbolic shape that is frequently found in unimodal grain size distributions in natural sand deposits, as pointed out...

  1. Size effects in manufacturing of metallic components

    DEFF Research Database (Denmark)

    Vollertsen, F; Biermann, D; Hansen, Hans Nørgaard

    2009-01-01

    In manufacturing of metallic components, the size of the part plays an important role for the process behaviour. This is due to so called size effects, which lead to changes in the process behaviour even if the relationship between the main geometrical features is kept constant. The aim of this p......In manufacturing of metallic components, the size of the part plays an important role for the process behaviour. This is due to so called size effects, which lead to changes in the process behaviour even if the relationship between the main geometrical features is kept constant. The aim...... of this paper is to give a systematic review on Such effects and their potential use or remedy. First, the typology of size effects will be explained, followed by a description of size effects on strength and tribology. The last three sections describe size effects on formability, forming processes and cutting...

  2. Phase transitions modern applications

    CERN Document Server

    Gitterman, Moshe

    2014-01-01

    This book provides a comprehensive review of the theory of phase transitions and its modern applications, based on the five pillars of the modern theory of phase transitions i.e. the Ising model, mean field, scaling, renormalization group and universality. This expanded second edition includes, along with a description of vortices and high temperature superconductivity, a discussion of phase transitions in chemical reaction and moving systems. The book covers a close connection between phase transitions and small world phenomena as well as scale-free systems such as the stock market and the Internet. Readership: Scientists working in different fields of physics, chemistry, biology and economics as well as teaching material for undergraduate and graduate courses.

  3. Now entering phase two...

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    Building on the success of their feasibility phase, the CLIC test facility, CTF3, has just launched into a five-year project development phase. This will involve detailed performance optimisation studies, marking the project’s transition from pure research and development to prototyping and construction.   CLIC accelerator modules under construction at CERN. “With the feasibility phase now complete, we have established that CLIC can be built,” says Roberto Corsini, CLIC Collaboration spokesperson. “Now we want to be sure that it can provide the luminosity and energy performance needed. We will be looking at the engineering, performance and cost of a real CLIC machine also seeing if we can reduce it.” CTF3’s second phase will focus on selected performance-related research areas for further investigation. The largest of these involves the construction and testing of several authentic CLIC accelerator modules that are currently being ...

  4. Disordered adsorbate phases

    Science.gov (United States)

    Rys, Franz S.

    1985-04-01

    The occurrence of disordered phases at low temperatures in adsorbed monolayers, as shown recently in a domain wall model, is discussed, the main results are summarized and some relevant experimental systems are mentionned.

  5. Multipulse phase resetting curves

    OpenAIRE

    Krishnan, Giri P.; Bazhenov, Maxim; Pikovsky, Arkady

    2013-01-01

    In this paper, we introduce and study systematically, in terms of phase response curves, the effect of dual-pulse excitation on the dynamics of an autonomous oscillator. Specifically, we test the deviations from linear summation of phase advances resulting from two small perturbations. We analytically derive a correction term, which generally appears for oscillators whose intrinsic dimensionality is >1. The nonlinear correction term is found to be proportional to the square of the perturbatio...

  6. Kinetics of phase change

    Directory of Open Access Journals (Sweden)

    A.C. Faleiros

    2000-07-01

    Full Text Available The kinetic model for change of phases developed by M. Avrami at the end of the thirties has been used to describe the temporal behavior of phase changes. Until today this model is studied and adapted to include broader hypotheses. However, the mathematical format presented by M. Avrami is difficult to be understood by beginners. The purpose of this work is to clarify the mathematical treatment of Avrami's work, going straightforward to the arguments that led to his main results.

  7. RNA gets in phase.

    Science.gov (United States)

    Saha, Shambaditya; Hyman, Anthony A

    2017-08-07

    Several neurological disorders are linked to tandem nucleotide repeat expansion in the mutated gene. Jain and Vale (2017. Nature. https://doi.org/10.1038/nature22386) show that, above a pathological threshold repeat number, base pairing interactions drive phase separation of RNA into membrane-less gels, suggesting that RNA can scaffold the assembly of phase-separated compartments that sequester proteins/RNAs causing toxicity. © 2017 Saha and Hyman.

  8. Two phase sampling

    CERN Document Server

    Ahmad, Zahoor; Hanif, Muhammad

    2013-01-01

    The development of estimators of population parameters based on two-phase sampling schemes has seen a dramatic increase in the past decade. Various authors have developed estimators of population using either one or two auxiliary variables. The present volume is a comprehensive collection of estimators available in single and two phase sampling. The book covers estimators which utilize information on single, two and multiple auxiliary variables of both quantitative and qualitative nature. Th...

  9. Exact phase boundaries and topological phase transitions of the X Y Z spin chain

    Science.gov (United States)

    Jafari, S. A.

    2017-07-01

    Within the block spin renormalization group, we give a very simple derivation of the exact phase boundaries of the X Y Z spin chain. First, we identify the Ising order along x ̂ or y ̂ as attractive renormalization group fixed points of the Kitaev chain. Then, in a global phase space composed of the anisotropy λ of the X Y interaction and the coupling Δ of the Δ σzσz interaction, we find that the above fixed points remain attractive in the two-dimesional parameter space. We therefore classify the gapped phases of the X Y Z spin chain as: (1) either attracted to the Ising limit of the Kitaev-chain, which in turn is characterized by winding number ±1 , depending on whether the Ising order parameter is along x ̂ or y ̂ directions; or (2) attracted to the charge density wave (CDW) phases of the underlying Jordan-Wigner fermions, which is characterized by zero winding number. We therefore establish that the exact phase boundaries of the X Y Z model in Baxter's solution indeed correspond to topological phase transitions. The topological nature of the phase transitions of the X Y Z model justifies why our analytical solution of the three-site problem that is at the core of the present renormalization group treatment is able to produce the exact phase boundaries of Baxter's solution. We argue that the distribution of the winding numbers between the three Ising phases is a matter of choice of the coordinate system, and therefore the CDW-Ising phase is entitled to host appropriate form of zero modes. We further observe that in the Kitaev-chain the renormalization group flow can be cast into a geometric progression of a properly identified parameter. We show that this new parameter is actually the size of the (Majorana) zero modes.

  10. Modeling the Effects of Beam Size and Flaw Morphology on Ultrasonic Pulse/Echo Sizing of Delaminations in Carbon Composites

    Science.gov (United States)

    Margetan, Frank J.; Leckey, Cara A.; Barnard, Dan

    2012-01-01

    The size and shape of a delamination in a multi-layered structure can be estimated in various ways from an ultrasonic pulse/echo image. For example the -6dB contours of measured response provide one simple estimate of the boundary. More sophisticated approaches can be imagined where one adjusts the proposed boundary to bring measured and predicted UT images into optimal agreement. Such approaches require suitable models of the inspection process. In this paper we explore issues pertaining to model-based size estimation for delaminations in carbon fiber reinforced laminates. In particular we consider the influence on sizing when the delamination is non-planar or partially transmitting in certain regions. Two models for predicting broadband sonic time-domain responses are considered: (1) a fast "simple" model using paraxial beam expansions and Kirchhoff and phase-screen approximations; and (2) the more exact (but computationally intensive) 3D elastodynamic finite integration technique (EFIT). Model-to-model and model-to experiment comparisons are made for delaminations in uniaxial composite plates, and the simple model is then used to critique the -6dB rule for delamination sizing.

  11. Electroweak phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Gregory W. [Univ. of California, Berkeley, CA (United States)

    1991-09-16

    An analytic treatment of the one Higgs doublet, electroweak phase transition is given. The phase transition is first order, occurs by the nucleation of thin walled bubbles and completes at a temperature where the order parameter, <Φ>T is significantly smaller than it is when the origin becomes absolutely unstable. The rate of anomalous baryon number violation is an exponentially function of <Φ>T. In very minimal extensions of the standard model it is quite easy to increase <Φ>T so that anomalous baryon number violation is suppressed after completion of the phase transition. Hence baryogenesis at the electroweak phase transition is tenable in minimal of the standard model. In some cases additional phase transitions are possible. For a light Higgs boson, when the top quark mass is sufficiently large, the state where the Higgs field has a vacuum expectation value <Φ> = 246 GeV is not the true minimum of the Higgs potential. When this is the case, and when the top quark mass exceeds some critical value, thermal fluctuations in the early universe would have rendered the state <Φ> = 246 GeV unstable. The requirement that the state <Φ> = 246 GeV is sufficiently long lived constrains the masses of the Higgs boson and the top quark. Finally, we consider whether local phase transitions can be induced by heavy particles which act as seeds for deformations in the scalar field.

  12. OPTIMAL SAMPLE SIZE FOR STATISTICAL ANALYSIS OF WINTER WHEAT QUANTITATIVE TRAITS

    OpenAIRE

    Andrijana Eđed; Dražen Horvat; Zdenko Lončarić

    2009-01-01

    In the planning phase of every research particular attention should be dedicated to estimation of optimal sample size, aiming to obtain more precise and objective results of statistical analysis. The aim of this paper was to estimate optimal sample size of wheat yield components (plant height, spike length, number of spikelets per spike, number of grains per spike, weight of grains per spike and 1000 grains weight) for determination of statistically significant differences between two treatme...

  13. The effects of particle shape and size on T2 relaxation in magnetic resonance imaging.

    Science.gov (United States)

    York, Joseph N; Albanese, Christopher; Rodriguez, Olga; Le, Yi-Chien; Ackun-Farmmer, Marian; Van Keuren, Edward

    2014-11-01

    Superparamagnetic iron oxide nanoparticles have recently been developed as T2 contrast agents for magnetic resonance imaging. Here we report the dependence of the phase relaxivity, r2, on the particle shape. We show that the size dependence of the relaxivity for spherical particles can be generalized to spheroidal particles. In addition, we show that the saturation of relaxivity above a certain size observed in spherical particles does not occur in the spheroidal particles investigated.

  14. Development of a Size Exclusion Chromatography metod for analysis of extraction solutions from urinary catheters

    OpenAIRE

    Ericsson, Victoria

    2010-01-01

    This project focused on developing a Size Exclusion Chromatography (SEC) methodwith Refractive Index (RI) detection for analysis of extraction samples from urinarycatheters to detect compounds that can be extracted from the catheter during use.Mobile phases, extraction fluids and sample concentrations were varied, as well aspore sizes of the columns, to investigate the applicability of this technique forcharacterization of the coating and potential leachables. Analyses of extractionsamples sh...

  15. Effect of phase transformations on microstructures in deep mantle materials

    Science.gov (United States)

    Merkel, Sébastien; Langrand, Christopher; Rosa, Angelika; Hilairet, Nadège

    2017-04-01

    Phase transformations induce microstructural changes in deep Earth materials, including changes in grain size and orientation distribution. The effect of phase transformations on mineral microstructures is usually studied using electron microscopy on quench products from high P/T experiments. The method allows for a precise evaluation of the microscopic mechanisms involved. It is limited, however, to samples that can be quenched to ambient conditions and allows for investigations at a single P/T point for each experiment. In recent years, we extended the use of multigrain crystallography to samples inside diamond anvil cells under mantle P/T conditions. The method allows for monitoring the orientations of hundreds of grains and grain size variations during various physical processes, such as plastic deformation and successions of phase transformations (Rosa et al 2015, Langrand et al 2017). Here, we will show results concerning hydrous Mg2SiO4 during the series of α-β-γ phase transformations up to 40 GPa and 850 °C. Such results are important to understand the descending behaviour of subducted slabs, observations of seismic anisotropy, and polarity changes for seismic waves reflected of deep Earth interfaces. The data is used to asses the effect of the transformation on grain orientation and grain sizes. In particular, we do not observe orientation relationships between the parent α-phase and the daughter β-phase phase, suggesting an incoherent growth. We also observe significant grain size reductions and only little grain growth within the newly formed phases (Rosa et al 2016). These new results are important for understanding the mechanical behavior of subducting slabs, seismic anisotropy in the Earth's mantle, and phase transformation mechanisms in olivine. Now that it is validated, the method can also be applied to other phases that can not be studied using electron microscopy, such as perovskite and post-perovskite. Langrand, Hilairet, Nisr, Roskosz, Rib

  16. Interaction of lysozyme protein with different sized silica nanoparticles and their resultant structures

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Indresh, E-mail: iykumarindresh288@gmail.com; Aswal, V. K. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Kohlbrecher, J. [Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 PSI Villigen (Switzerland)

    2016-05-23

    The interaction of model protein-lysozyme with three different sized anionic silica nanoparticles has been studied by UV-vis spectroscopy, dynamic light scattering (DLS) and small-angle neutron scattering (SANS). The surface area and curvature of the nanoparticles change with size, which significantly influence their interaction with protein. The lysozyme adsorbs on the surface of the nanoparticles due to electrostatic attraction and leads to the phase transformation from one phase (clear) to two-phase (turbid) of the nanoparticle-protein system. The dominance of lysozyme induced short-range attraction over long-range electrostatic repulsion between nanoparticles is responsible for phase transformation and modeled by the two-Yukawa potential. The magnitude of the attractive interaction increases with the size of the nanoparticles as a result the phase transformation commences relatively at lower concentration of lysozyme. The structure of the nanoparticle-protein system in two-phase is characterized by the diffusion limited aggregate type of mass fractal morphology.

  17. Developing a size indicator for fish populations

    Directory of Open Access Journals (Sweden)

    Yong Chen

    2008-06-01

    Full Text Available Monitoring temporal and/or spatial variations in fish size-at-age data can often provide fisheries managers with important information about the status of fish stocks and therefore help them identify necessary changes in management policies. However, due to the multivariate nature of size-at-age data, commonly used single-age-based approaches ignore covariance between sizes of different age groups. Different results may therefore be derived when evaluating temporal variations using different age groups for the comparison. The possibility of atypical errors in size-at-age data due to ageing and measurement errors further complicates the comparison. We propose a two-step approach for developing an indicator for monitoring temporal and/or spatial variation in size-at-age data. A robust approach, minimum volume ellipsoid analysis, is used to identify possible outliers in size-at-age data. Then a weighted principal component analysis is applied to the data with the identified outliers down-weighted. An indicator is defined from the resultant principal components for monitoring temporal/spatial variations in size-at-age data. We illustrate the proposed approach with size-at-age data for cod (Gadus morhua in the northwest Atlantic, NAFO subdivision 3Ps. The overall size-at-age indicator identified shows that the pre-1980 year classes tend to have a much higher size-at-age than the post-1980 year classes.

  18. Phases of kinky holographic nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    Elliot-Ripley, Matthew; Sutcliffe, Paul; Zamaklar, Marija [Department of Mathematical Sciences, Durham University,South Road, Durham (United Kingdom)

    2016-10-17

    Holographic QCD at finite baryon number density and zero temperature is studied within the five-dimensional Sakai-Sugimoto model. We introduce a new approximation that models a smeared crystal of solitonic baryons by assuming spatial homogeneity to obtain an effective kink theory in the holographic direction. The kink theory correctly reproduces a first order phase transition to lightly bound nuclear matter. As the density is further increased the kink splits into a pair of half-kink constituents, providing a concrete realization of the previously suggested dyonic salt phase, where the bulk soliton splits into constituents at high density. The kink model also captures the phenomenon of baryonic popcorn, in which a first order phase transition generates an additional soliton layer in the holographic direction. We find that this popcorn transition takes place at a density below the dyonic salt phase, making the latter energetically unfavourable. However, the kink model predicts only one pop, rather than the sequence of pops suggested by previous approximations. In the kink model the two layers produced by the single pop form the surface of a soliton bag that increases in size as the baryon chemical potential is increased. The interior of the bag is filled with abelian electric potential and the instanton charge density is localized on the surface of the bag. The soliton bag may provide a holographic description of a quarkyonic phase.

  19. Size as a determinant of reading speed

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, I.; Clear, R.; Berman, S.

    1992-03-01

    The speed of reading unrelated words as a function of luminance, size, and contrast, was measured with an eye movement monitor for fifteen young adults. Subjects read up to 5,000 words in a test session, with the exact number depending upon their acuity. The size of the smallest legible print at a given luminance and contrast for these subjects was found to fit well to the Blackwell-Taylor detection threshold data above about 1 minute of arc. At lower sizes inclusion of a resolution size term provided an excellent fit. Reading speed was fit to a number of visual performance models. It was found that for most subjects that a ratio of the print size to an estimate of the threshold print size (a VL{sub size}) gave the best fits to the data. The threshold size was computed with a fit to the Blackwell-Taylor detection threshold data, modified to include a resolution size term as above. For the sole remaining subject a slightly better fit was obtained with a VL{sub contrast} model, where again the thresholds were modified by a limiting size term. The implication of these results for visual performance modeling is discussed. The reading speed for all subjects varied rapidly with size near the acuity limit, but became almost independent of visibility parameters as long as size is two times the acuity limit. These results show that size is a powerful determinant of reading speed, and suggest that minification of about 1/2 power could be used as a field test for adequate visibility.

  20. Size as a determinant of reading speed

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, I.; Clear, R.; Berman, S.

    1992-03-01

    The speed of reading unrelated words as a function of luminance, size, and contrast, was measured with an eye movement monitor for fifteen young adults. Subjects read up to 5,000 words in a test session, with the exact number depending upon their acuity. The size of the smallest legible print at a given luminance and contrast for these subjects was found to fit well to the Blackwell-Taylor detection threshold data above about 1 minute of arc. At lower sizes inclusion of a resolution size term provided an excellent fit. Reading speed was fit to a number of visual performance models. It was found that for most subjects that a ratio of the print size to an estimate of the threshold print size (a VL[sub size]) gave the best fits to the data. The threshold size was computed with a fit to the Blackwell-Taylor detection threshold data, modified to include a resolution size term as above. For the sole remaining subject a slightly better fit was obtained with a VL[sub contrast] model, where again the thresholds were modified by a limiting size term. The implication of these results for visual performance modeling is discussed. The reading speed for all subjects varied rapidly with size near the acuity limit, but became almost independent of visibility parameters as long as size is two times the acuity limit. These results show that size is a powerful determinant of reading speed, and suggest that minification of about 1/2 power could be used as a field test for adequate visibility.

  1. Phase Diagrams of Electrostatically Self-Assembled Amphiplexes

    Energy Technology Data Exchange (ETDEWEB)

    V Stanic; M Mancuso; W Wong; E DiMasi; H Strey

    2011-12-31

    We present the phase diagrams of electrostatically self-assembled amphiplexes (ESA) comprised of poly(acrylic acid) (PAA), cetyltrimethylammonium chloride (CTACl), dodecane, pentanol, and water at three different NaCl salt concentrations: 100, 300, and 500 mM. This is the first report of phase diagrams for these quinary complexes. Adding a cosurfactant, we were able to swell the unit cell size of all long-range ordered phases (lamellar, hexagonal, Pm3n, Ia3d) by almost a factor of 2. The added advantage of tuning the unit cell size makes such complexes (especially the bicontinuous phases) attractive for applications in bioseparation, drug delivery, and possibly in oil recovery.

  2. Preliminary Phase Field Computational Model Development

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yulan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hu, Shenyang Y. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Ke [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Suter, Jonathan D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McCloy, John S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Bradley R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-15

    This interim report presents progress towards the development of meso-scale models of magnetic behavior that incorporate microstructural information. Modeling magnetic signatures in irradiated materials with complex microstructures (such as structural steels) is a significant challenge. The complexity is addressed incrementally, using the monocrystalline Fe (i.e., ferrite) film as model systems to develop and validate initial models, followed by polycrystalline Fe films, and by more complicated and representative alloys. In addition, the modeling incrementally addresses inclusion of other major phases (e.g., martensite, austenite), minor magnetic phases (e.g., carbides, FeCr precipitates), and minor nonmagnetic phases (e.g., Cu precipitates, voids). The focus of the magnetic modeling is on phase-field models. The models are based on the numerical solution to the Landau-Lifshitz-Gilbert equation. From the computational standpoint, phase-field modeling allows the simulation of large enough systems that relevant defect structures and their effects on functional properties like magnetism can be simulated. To date, two phase-field models have been generated in support of this work. First, a bulk iron model with periodic boundary conditions was generated as a proof-of-concept to investigate major loop effects of single versus polycrystalline bulk iron and effects of single non-magnetic defects. More recently, to support the experimental program herein using iron thin films, a new model was generated that uses finite boundary conditions representing surfaces and edges. This model has provided key insights into the domain structures observed in magnetic force microscopy (MFM) measurements. Simulation results for single crystal thin-film iron indicate the feasibility of the model for determining magnetic domain wall thickness and mobility in an externally applied field. Because the phase-field model dimensions are limited relative to the size of most specimens used in

  3. Predicting grid-size-dependent fracture strains of DP980 with a microstructure-based post-necking model

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, G.; Hu, X. H.; Choi, K. S.; Sun, X.

    2017-07-08

    Ductile fracture is a local phenomenon, and it is well established that fracture strain levels depend on both stress triaxiality and the resolution (grid size) of strain measurements. Two-dimensional plane strain post-necking models with different representative volume element (RVE) sizes are used to predict the size-dependent fracture strain of a commercial dual-phase steel, DP980. The models are generated from the actual microstructures, and the individual phase flow properties and literature-based individual phase damage parameters for the Johnson-Cook model are used for ferrite and martensite. A monotonic relationship is predicted: the smaller the model size, the higher the fracture strain. Thus, a general framework is developed to quantify the size-dependent fracture strains for multiphase materials. In addition to the RVE sizes, the influences of intrinsic microstructure features, i.e., the flow curve and fracture strains of the two constituent phases, on the predicted fracture strains also are examined. Application of the derived fracture strain versus RVE size relationship is demonstrated with large clearance trimming simulations with different element sizes.

  4. Portion Size Labeling and Intended Soft Drink Consumption: The Impact of Labeling Format and Size Portfolio

    Science.gov (United States)

    Vermeer, Willemijn M.; Steenhuis, Ingrid H. M.; Leeuwis, Franca H.; Bos, Arjan E. R.; de Boer, Michiel; Seidell, Jacob C.

    2010-01-01

    Objective: To assess what portion size labeling "format" is most promising in helping consumers selecting appropriate soft drink sizes, and whether labeling impact depends on the size portfolio. Methods: An experimental study was conducted in fast-food restaurants in which 2 labeling formats (ie, reference portion size and small/medium/large…

  5. Experimental Study Using Functional Size Measurement in Building Estimation Models for Software Project Size

    NARCIS (Netherlands)

    Condori-Fernandez, Nelly; Daneva, Maia; Buglione, Luigi; Ormandjieva, Olga; Ormandjieva, O.; Constantinides, C.; Abran, A.; Lee, R.

    2010-01-01

    This paper reports on an experiment that investigates the predictability of software project size from software product size. The predictability research problem is analyzed at the stage of early requirements by accounting the size of functional requirements as well as the size of non-functional

  6. First Temperate Exoplanet Sized Up

    Science.gov (United States)

    2010-03-01

    Combining observations from the CoRoT satellite and the ESO HARPS instrument, astronomers have discovered the first "normal" exoplanet that can be studied in great detail. Designated Corot-9b, the planet regularly passes in front of a star similar to the Sun located 1500 light-years away from Earth towards the constellation of Serpens (the Snake). "This is a normal, temperate exoplanet just like dozens we already know, but this is the first whose properties we can study in depth," says Claire Moutou, who is part of the international team of 60 astronomers that made the discovery. "It is bound to become a Rosetta stone in exoplanet research." "Corot-9b is the first exoplanet that really does resemble planets in our solar system," adds lead author Hans Deeg. "It has the size of Jupiter and an orbit similar to that of Mercury." "Like our own giant planets, Jupiter and Saturn, the planet is mostly made of hydrogen and helium," says team member Tristan Guillot, "and it may contain up to 20 Earth masses of other elements, including water and rock at high temperatures and pressures." Corot-9b passes in front of its host star every 95 days, as seen from Earth [1]. This "transit" lasts for about 8 hours, and provides astronomers with much additional information on the planet. This is fortunate as the gas giant shares many features with the majority of exoplanets discovered so far [2]. "Our analysis has provided more information on Corot-9b than for other exoplanets of the same type," says co-author Didier Queloz. "It may open up a new field of research to understand the atmospheres of moderate- and low-temperature planets, and in particular a completely new window in our understanding of low-temperature chemistry." More than 400 exoplanets have been discovered so far, 70 of them through the transit method. Corot-9b is special in that its distance from its host star is about ten times larger than that of any planet previously discovered by this method. And unlike all such

  7. Improvement of the image quality of random phase--free holography using an iterative method

    CERN Document Server

    Shimobaba, Tomoyoshi; Endo, Yutaka; Hirayama, Ryuji; Hiyama, Daisuke; Hasegawa, Satoki; Nagahama, Yuki; Sano, Marie; Oikawa, Minoru; Sugie, Takashige; Ito, Tomoyoshi

    2015-01-01

    Our proposed method of random phase-free holography using virtual convergence light can obtain large reconstructed images exceeding the size of the hologram, without the assistance of random phase. The reconstructed images have low-speckle noise in the amplitude and phase-only holograms (kinoforms); however, in low-resolution holograms, we obtain a degraded image quality compared to the original image. We propose an iterative random phase-free method with virtual convergence light to address this problem.

  8. Launch vehicle design and GNC sizing with ASTOS

    Science.gov (United States)

    Cremaschi, Francesco; Winter, Sebastian; Rossi, Valerio; Wiegand, Andreas

    2017-06-01

    The European Space Agency (ESA) is currently involved in several activities related to launch vehicle designs (Future Launcher Preparatory Program, Ariane 6, VEGA evolutions, etc.). Within these activities, ESA has identified the importance of developing a simulation infrastructure capable of supporting the multi-disciplinary design and preliminary guidance navigation and control (GNC) design of different launch vehicle configurations. Astos Solutions has developed the multi-disciplinary optimization and launcher GNC simulation and sizing tool (LGSST) under ESA contract. The functionality is integrated in the Analysis, Simulation and Trajectory Optimization Software for space applications (ASTOS) and is intended to be used from the early design phases up to phase B1 activities. ASTOS shall enable the user to perform detailed vehicle design tasks and assessment of GNC systems, covering all aspects of rapid configuration and scenario management, sizing of stages, trajectory-dependent estimation of structural masses, rigid and flexible body dynamics, navigation, guidance and control, worst case analysis, launch safety analysis, performance analysis, and reporting.

  9. Private Set Intersection for Unequal Set Sizes with Mobile Applications

    Directory of Open Access Journals (Sweden)

    Kiss Ágnes

    2017-10-01

    Full Text Available Private set intersection (PSI is a cryptographic technique that is applicable to many privacy-sensitive scenarios. For decades, researchers have been focusing on improving its efficiency in both communication and computation. However, most of the existing solutions are inefficient for an unequal number of inputs, which is common in conventional client-server settings. In this paper, we analyze and optimize the efficiency of existing PSI protocols to support precomputation so that they can efficiently deal with such input sets. We transform four existing PSI protocols into the precomputation form such that in the setup phase the communication is linear only in the size of the larger input set, while in the online phase the communication is linear in the size of the smaller input set. We implement all four protocols and run experiments between two PCs and between a PC and a smartphone and give a systematic comparison of their performance. Our experiments show that a protocol based on securely evaluating a garbled AES circuit achieves the fastest setup time by several orders of magnitudes, and the fastest online time in the PC setting where AES-NI acceleration is available. In the mobile setting, the fastest online time is achieved by a protocol based on the Diffie-Hellman assumption.

  10. Estimating Search Engine Index Size Variability

    DEFF Research Database (Denmark)

    Van den Bosch, Antal; Bogers, Toine; De Kunder, Maurice

    2016-01-01

    One of the determining factors of the quality of Web search engines is the size of their index. In addition to its influence on search result quality, the size of the indexed Web can also tell us something about which parts of the WWW are directly accessible to the everyday user. We propose a novel...... method of estimating the size of a Web search engine’s index by extrapolating from document frequencies of words observed in a large static corpus of Web pages. In addition, we provide a unique longitudinal perspective on the size of Google and Bing’s indices over a nine-year period, from March 2006...... until January 2015. We find that index size estimates of these two search engines tend to vary dramatically over time, with Google generally possessing a larger index than Bing. This result raises doubts about the reliability of previous one-off estimates of the size of the indexed Web. We find...

  11. A merchant ship size optimization model

    OpenAIRE

    Choi, Ki-Chul

    1983-01-01

    Approved for public release; distribution in unlimited. This paper analyzes how a shipowner or charterer may determine the specification of optimal ship size for a given route with respect to certain market requirements . The theory of optimal ship size, a methodology for estimating scale economics, and the various factors affecting ship size are examined using a typical conventional cargo ship and bulk cargo carriers based on shipowners ' cost data. http://archi...

  12. Effective Size of Nonrandom Mating Populations

    OpenAIRE

    Caballero, A.; Hill, W. G.

    1992-01-01

    Nonrandom mating whereby parents are related is expected to cause a reduction in effective population size because their gene frequencies are correlated and this will increase the genetic drift. The published equation for the variance effective size, N(e), which includes the possibility of nonrandom mating, does not take into account such a correlation, however. Further, previous equations to predict effective sizes in populations with partial sib mating are shown to be different, but also in...

  13. Single-phase to three-phase power conversion interface

    Science.gov (United States)

    Wu, Jinn-Chang; Wang, Yung-Shan; Jou, Hurng-Liahng; Lu, Wei-Tso

    2016-07-01

    This study proposes a single-phase to three-phase power conversion interface which converts the power from a single-phase utility to three-phase power for a three-phase load. The proposed single-phase to three-phase power conversion interface comprises a bridge-type switch set, a set of three-phase inductors, a transformer set and a set of three-phase capacitors. A current-mode control controls the switching of bridge-type switch set, to generate a set of nonzero-sequence (NZS) currents and a set of zero-sequence (ZS) currents. The transformer set is used to decouple the NZS currents and the ZS currents. The NZS currents are used to generate a high-quality three-phase voltage that supplies power to a three-phase load. The ZS currents flow to the single-phase utility so that the utility current is sinusoidal and in phase with the utility voltage. Accordingly, only a bridge-type switch set is used in the single-phase to three-phase power conversion interface to simply the power circuit. A prototype is developed and tested to verify the performance of the proposed single-phase to three-phase power conversion interface.

  14. Measurement of the pore size distribution of limestone aggregates in concrete pavement cores : phase I.

    Science.gov (United States)

    2012-04-01

    Freeze-thaw damage is one of the common forms of distress for concrete pavements in Kansas. D-Cracking is a form of : freeze-thaw damage caused by aggregates with poor freeze-thaw durability. It is believed that pores in the aggregates below : 10 m...

  15. PERSPECTIVE TECHNOLOGIES OF THERMAL HARDENING OF LARGE-SIZE ARTICLES OF TWO-PHASE TITANIUM ALLOYS

    Directory of Open Access Journals (Sweden)

    V. N. Fedulov

    2005-01-01

    Full Text Available The article is dedicated to the development and industrial assimilation of the fundamentally new methods of thermal strengthening of large articles out of hardenable titanic alloys.

  16. Assessment of Available Particle Size Data to Support an Analysis of the Waste Feed Delivery System Transfer System

    Energy Technology Data Exchange (ETDEWEB)

    JEWETT, J.R.

    2000-08-10

    Available data pertaining to size distribution of the particulates in Hanford underground tank waste have been reviewed. Although considerable differences exist between measurement methods, it may be stated with 95% confidence that the median particle size does not exceed 275 {micro}m in at least 95% of the ten tanks selected as sources of HLW feed for Phase 1 vitrification in the RPP. This particle size is recommended as a design basis for the WFD transfer system.

  17. Size dependent structural and magnetic properties of FeO-Fe3O4 nanoparticles

    Science.gov (United States)

    Lak, Aidin; Kraken, Mathias; Ludwig, Frank; Kornowski, Andreas; Eberbeck, Dietmar; Sievers, Sibylle; Litterst, F. J.; Weller, Horst; Schilling, Meinhard

    2013-11-01

    The magnetic properties of monodisperse FeO-Fe3O4 nanoparticles with different mean sizes and volume fractions of FeO synthesized via decomposition of iron oleate were correlated to their crystallographic and phase compositional features by exploiting high resolution transmission electron microscopy, X-ray diffraction, Mössbauer spectroscopy and field and zero field cooled magnetization measurements. A model describing the phase transformation from a pure Fe3O4 phase to a mixture of Fe3O4, FeO and interfacial FeO-Fe3O4 phases as the particle size increases was established. The reduced magnetic moment in FeO-Fe3O4 nanoparticles was attributed to the presence of differently oriented Fe3O4 crystalline domains in the outer layers and paramagnetic FeO phase. The exchange bias energy, dominating magnetization reversal mechanism and superparamagnetic blocking temperature in FeO-Fe3O4 nanoparticles depend strongly on the relative volume fractions of FeO and the interfacial phase.The magnetic properties of monodisperse FeO-Fe3O4 nanoparticles with different mean sizes and volume fractions of FeO synthesized via decomposition of iron oleate were correlated to their crystallographic and phase compositional features by exploiting high resolution transmission electron microscopy, X-ray diffraction, Mössbauer spectroscopy and field and zero field cooled magnetization measurements. A model describing the phase transformation from a pure Fe3O4 phase to a mixture of Fe3O4, FeO and interfacial FeO-Fe3O4 phases as the particle size increases was established. The reduced magnetic moment in FeO-Fe3O4 nanoparticles was attributed to the presence of differently oriented Fe3O4 crystalline domains in the outer layers and paramagnetic FeO phase. The exchange bias energy, dominating magnetization reversal mechanism and superparamagnetic blocking temperature in FeO-Fe3O4 nanoparticles depend strongly on the relative volume fractions of FeO and the interfacial phase. Electronic supplementary

  18. Aggregate size distributions in hydrophobic flocculation

    Directory of Open Access Journals (Sweden)

    Chairoj Rattanakawin

    2003-07-01

    Full Text Available The evolution of aggregate (floc size distributions resulting from hydrophobic flocculation has been investigated using a laser light scattering technique. By measuring floc size distributions it is possible to distinguish clearly among floc formation, growth and breakage. Hydrophobic flocculation of hematite suspensions with sodium oleate under a variety of agitating conditions produces uni-modal size distributions. The size distribution of the primary particles is shifted to larger floc sizes when the dispersed suspension is coagulated by pH adjustment. By adding sodium oleate to the pre-coagulated suspension, the distribution progresses further to the larger size. However, prolonged agitation degrades the formed flocs, regressing the distribution to the smaller size. Median floc size derived from the distribution is also used as performance criterion. The median floc size increases rapidly at the initial stage of the flocculation, and decreases with the extended agitation time and intensity. Relatively weak flocs are produced which may be due to the low dosage of sodium oleate used in this flocculation study. It is suggested that further investigation should focus on optimum reagent dosage and non-polar oil addition to strengthen these weak flocs.

  19. How to calculate sample size and why.

    Science.gov (United States)

    Kim, Jeehyoung; Seo, Bong Soo

    2013-09-01

    Calculating the sample size is essential to reduce the cost of a study and to prove the hypothesis effectively. Referring to pilot studies and previous research studies, we can choose a proper hypothesis and simplify the studies by using a website or Microsoft Excel sheet that contains formulas for calculating sample size in the beginning stage of the study. There are numerous formulas for calculating the sample size for complicated statistics and studies, but most studies can use basic calculating methods for sample size calculation.

  20. Sample size determination for the fluctuation experiment.

    Science.gov (United States)

    Zheng, Qi

    2017-01-01

    The Luria-Delbrück fluctuation experiment protocol is increasingly employed to determine microbial mutation rates in the laboratory. An important question raised at the planning stage is "How many cultures are needed?" For over 70 years sample sizes have been determined either by intuition or by following published examples where sample sizes were chosen intuitively. This paper proposes a practical method for determining the sample size. The proposed method relies on existing algorithms for computing the expected Fisher information under two commonly used mutant distributions. The role of partial plating in reducing sample size is discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Particle size distribution instrument. Topical report 13

    Energy Technology Data Exchange (ETDEWEB)

    Okhuysen, W.; Gassaway, J.D.

    1995-04-01

    The development of an instrument to measure the concentration of particles in gas is described in this report. An in situ instrument was designed and constructed which sizes individual particles and counts the number of occurrences for several size classes. Although this instrument was designed to detect the size distribution of slag and seed particles generated at an experimental coal-fired magnetohydrodynamic power facility, it can be used as a nonintrusive diagnostic tool for other hostile industrial processes involving the formation and growth of particulates. Two of the techniques developed are extensions of the widely used crossed beam velocimeter, providing simultaneous measurement of the size distribution and velocity of articles.

  2. Performance of population size on Knapsack problem

    Directory of Open Access Journals (Sweden)

    David Oyewola

    2016-12-01

    Full Text Available In this paper, an investigation of a performance of population size on the genetic algorithm (GA for a knapsack problem is considered. Population sizes between 10 and 200 chromosomes in the population are tested. In order to obtain meaningful information about the performance of the population size, a considerable number of independent runs of the GA are performed. Accurate model parameters values are obtained in reasonable computational time. Further increase of the population size, does not improve the solution accuracy. Moreover, the computational time is increased significantly.

  3. Matters of fiber size and myonuclear domain

    DEFF Research Database (Denmark)

    Karlsen, Anders; Couppé, Christian; Andersen, Jesper L.

    2015-01-01

    INTRODUCTION: The relationship between fiber size and myonuclear content is understood poorly. METHODS: Biopsy cross-sections from young and old trained and untrained healthy individuals were analyzed for fiber area and myonuclei, and 2 fiber size-dependent cluster analyses were performed. RESULTS...... in fibers type II fibers below 3,000 μm(2) was observed in the old. DISCUSSION: These findings suggest that age-related reductions in myonuclear domain size could be explained by a larger proportion of small fibers and highlight the usefulness of fiber size...

  4. Biofunctional Understanding and Judgment of Size

    Directory of Open Access Journals (Sweden)

    Zheng eJin

    2016-03-01

    Full Text Available Research has shown that the meaningfulness of the material increases judged size, whereas symmetry decreases size judgments. These findings have been interpreted in terms of information processing, with a greater quantity of information leading to a judgment of larger size. An alternative view based on biofunctional understanding theory emphasizes the quality of affordance-triggered biological activity as reported and observed in attitudes toward playing sports, effortless understanding, knowledge-in-action, meditative wisdom, and body-mind cycle of adaptation. This alternative implies that affordance biofunctional activity is naturally size-diminishinging as it moves toward coherence and size-expanding as it moves away from coherence influencing judgments of size accordingly. Here we tested this hypothesis in the realm of sensorimotor integration. Our first experiment showed that phonologically unpronounced or symmetric symbols elicit smaller size judgments than phonologically pronounced and asymmetric symbols. Next, we manipulated the quantity of meaning with the affordance (possibilities for biofunctional activity orthogonally in a second experiment, results indicated that meaning affects size judgments only in the absence of phonological information. We conclude that the biofunctional activity affordance may be responsible for observed differences in size judgment.

  5. Acute-phase reactants

    Directory of Open Access Journals (Sweden)

    Harpreet Singh Grover

    2016-01-01

    Full Text Available The acute-phase response (APR is a prominent systemic reaction of the organism to local or systemic disturbances in its homeostasis caused by infection, tissue injury, trauma or surgery, or immunological disorders. The tissue macrophage is most commonly regarded as initiating the APR through direct stimulation and secretion of various cell communicating factors. Proinflammatory cytokines and mediators are significantly elevated with gingival inflammation and during the destructive phase of periodontitis. Cytokines appear to play a major role in the clinical symptoms and tissue destruction associated with progressing periodontitis. Many of these cytokines are derived from activated macrophages and can act both locally and distally to amplify cytokine production from other cell types. The host responses to periodontal disease and cardiovascular diseases were reflected by an increase in the acute-phase proteins (serum amyloid A and C-reactive protein.

  6. Rutile nanopowders for pigment production: Formation mechanism and particle size prediction

    Science.gov (United States)

    Zhang, Wu; Tang, Hongxin

    2018-01-01

    Formation mechanism and particle size prediction of rutile nanoparticles for pigment production were investigated. Anatase nanoparticles were observed by oriented attachment with parallel lattice fringe spaces of 0.2419 nm. Upon increasing the calcination temperature, the (1 1 0) plane of rutile was gradually observed, suggesting that the anatase (1 0 3) planes undergo internal structural rearrangement of oxygen and titanium ions into rutile phase due to ionic diffusion. Backpropagation neural network was used to predict particle size of rutile nanopowders, the prediction errors were all smaller than 2%, providing an efficient method to control particle size in pigment production.

  7. Phase coexistence in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Gulminelli, F

    2003-05-01

    In this work the general theory of first order phase transitions in finite systems is discussed, with a special emphasis to the conceptual problems linked to a thermodynamic description for small, short-lived systems de-exciting in the vacuum as nuclear samples coming from heavy ion collisions. After a short review of the general theory of phase transitions in the framework of information theory; we will present the different possible extensions to the field of finite systems. The concept of negative heat capacity, developed in the early seventies in the context of self-gravitating systems, will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. A careful study of the thermodynamic limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. In the second part of the paper we will apply the theoretical ideas developed in the first part to the possible observation of a liquid-to-gas-like phase transition in heavy ion collisions. The applicability of equilibrium concepts in a dynamical collisional process without boundary conditions will first be critically discussed. The observation of abnormally large partial energy fluctuations in carefully selected samples of collisions detected with the MULTICS-Miniball array will then be reported as a strong evidence of a first order phase transition with negative heat capacity in the nuclear equation of state. (author)

  8. Electroweak phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, G.W.

    1991-09-16

    An analytic treatment of the one Higgs doublet, electroweak phase transition is given. The phase transition is first order, occurs by the nucleation of thin walled bubbles and completes at a temperature where the order parameter, {l angle}{phi}{r angle}{sub T} is significantly smaller than it is when the origin becomes absolutely unstable. The rate of anomalous baryon number violation is an exponentially function of {l angle}{phi}{r angle}{sub T}. In very minimal extensions of the standard model it is quite easy to increase {l angle}{phi}{r angle}{sub T} so that anomalous baryon number violation is suppressed after completion of the phase transition. Hence baryogenesis at the electroweak phase transition is tenable in minimal of the standard model. In some cases additional phase transitions are possible. For a light Higgs boson, when the top quark mass is sufficiently large, the state where the Higgs field has a vacuum expectation value {l angle}{phi}{r angle} = 246 GeV is not the true minimum of the Higgs potential. When this is the case, and when the top quark mass exceeds some critical value, thermal fluctuations in the early universe would have rendered the state {l angle}{phi}{r angle} = 246 GeV unstable. The requirement that the state {l angle}{phi}{r angle} = 246 GeV is sufficiently long lived constrains the masses of the Higgs boson and the top quark. Finally, we consider whether local phase transitions can be induced by heavy particles which act as seeds for deformations in the scalar field.

  9. An influence of vacancies and elastic deformation coupling onto phase decomposition of binary systems

    Science.gov (United States)

    Kharchenko, Dmitrii O.; Kharchenko, Vasyl O.; Lysenko, Irina O.; Shuda, Irina A.

    2017-11-01

    We present a comprehensive study of phase decomposition of binary alloys by taking into account lattice mismatch, coupling of both solute and vacancy concentrations with elastic deformation and multiplicative noise satisfying fluctuation dissipation relation. We discuss scaling dynamics and universality of domain size growth. We verified numerically delaying dynamics of mean domain size growth caused by field dependent mobilities. It is shown that vacancy-deformation coupling leads to vacancies agglomeration in soft phase, it suppress phase decomposition at early stages and promotes an increase in the domain size at late stages.

  10. Understanding quantum phase transitions

    CERN Document Server

    Carr, Lincoln

    2010-01-01

    Quantum phase transitions (QPTs) offer wonderful examples of the radical macroscopic effects inherent in quantum physics: phase changes between different forms of matter driven by quantum rather than thermal fluctuations, typically at very low temperatures. QPTs provide new insight into outstanding problems such as high-temperature superconductivity and display fundamental aspects of quantum theory, such as strong correlations and entanglement. Over the last two decades, our understanding of QPTs has increased tremendously due to a plethora of experimental examples, powerful new numerical meth

  11. Solid phase transformations

    CERN Document Server

    Čermák, J

    2008-01-01

    This special-topic book, devoted to ""Solid Phase Transformations"" , covers a broad range of phenomena which are of importance in a number of technological processes. Most commercial alloys undergo thermal treatment after casting, with the aim of imparting desired compositions and/or optimal morphologies to the component phases. In spite of the fact that the topic has lain at the center of physical metallurgy for a long time, there are numerous aspects which are wide open to potential investigative breakthroughs. Materials with new structures also stimulate research in the field, as well as n

  12. Electronic phase transitions

    CERN Document Server

    Kopaev, YuV

    1992-01-01

    Electronic Phase Transitions deals with topics, which are presently at the forefront of scientific research in modern solid-state theory. Anderson localization, which has fundamental implications in many areas of solid-state physics as well as spin glasses, with its influence on quite different research activities such as neural networks, are two examples that are reviewed in this book. The ab initio statistical mechanics of structural phase transitions is another prime example, where the interplay and connection of two unrelated disciplines of solid-state theory - first principle ele

  13. Compressive Phase Contrast Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Maia, Filipe; MacDowell, Alastair; Marchesini, Stefano; Padmore, Howard A.; Parkinson, Dula Y.; Pien, Jack; Schirotzek, Andre; Yang, Chao

    2010-09-01

    When x-rays penetrate soft matter, their phase changes more rapidly than their amplitude. Interference effects visible with high brightness sources creates higher contrast, edge enhanced images. When the object is piecewise smooth (made of big blocks of a few components), such higher contrast datasets have a sparse solution. We apply basis pursuit solvers to improve SNR, remove ring artifacts, reduce the number of views and radiation dose from phase contrast datasets collected at the Hard X-Ray Micro Tomography Beamline at the Advanced Light Source. We report a GPU code for the most computationally intensive task, the gridding and inverse gridding algorithm (non uniform sampled Fourier transform).

  14. Phase Contrast Imaging

    DEFF Research Database (Denmark)

    1996-01-01

    The invention relates to a method and a system for synthesizing a prescribed intensity pattern based on phase contrast imaging that is not based on the assumption of prior art methods that the pahase shift phi is less than 1 radian. An improved method based on a simple imaging operation with a si......The invention relates to a method and a system for synthesizing a prescribed intensity pattern based on phase contrast imaging that is not based on the assumption of prior art methods that the pahase shift phi is less than 1 radian. An improved method based on a simple imaging operation...

  15. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 1 covers papers on the advances of gas phase ion chemistry. The book discusses the advances in flow tubes and the measurement of ion-molecule rate coefficients and product distributions; the ion chemistry of the earth's atmosphere; and the classical ion-molecule collision theory. The text also describes statistical methods in reaction dynamics; the state selection by photoion-photoelectron coincidence; and the effects of temperature and pressure in the kinetics of ion-molecule reactions. The energy distribution in the unimolecular decomposition of ions, as well

  16. Squamate hatchling size and the evolutionary causes of negative offspring size allometry.

    Science.gov (United States)

    Meiri, S; Feldman, A; Kratochvíl, L

    2015-02-01

    Although fecundity selection is ubiquitous, in an overwhelming majority of animal lineages, small species produce smaller number of offspring per clutch. In this context, egg, hatchling and neonate sizes are absolutely larger, but smaller relative to adult body size in larger species. The evolutionary causes of this widespread phenomenon are not fully explored. The negative offspring size allometry can result from processes limiting maximal egg/offspring size forcing larger species to produce relatively smaller offspring ('upper limit'), or from a limit on minimal egg/offspring size forcing smaller species to produce relatively larger offspring ('lower limit'). Several reptile lineages have invariant clutch sizes, where females always lay either one or two eggs per clutch. These lineages offer an interesting perspective on the general evolutionary forces driving negative offspring size allometry, because an important selective factor, fecundity selection in a single clutch, is eliminated here. Under the upper limit hypotheses, large offspring should be selected against in lineages with invariant clutch sizes as well, and these lineages should therefore exhibit the same, or shallower, offspring size allometry as lineages with variable clutch size. On the other hand, the lower limit hypotheses would allow lineages with invariant clutch sizes to have steeper offspring size allometries. Using an extensive data set on the hatchling and female sizes of > 1800 species of squamates, we document that negative offspring size allometry is widespread in lizards and snakes with variable clutch sizes and that some lineages with invariant clutch sizes have unusually steep offspring size allometries. These findings suggest that the negative offspring size allometry is driven by a constraint on minimal offspring size, which scales with a negative allometry. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary

  17. Simultaneous two-phase PIV by two-parameter phase discrimination

    Energy Technology Data Exchange (ETDEWEB)

    Khalitov, D.A.; Longmire, E.K. [Department of Aerospace Engineering and Mechanics University of Minnesota, NM (United States)

    2002-02-01

    A flexible and robust phase discrimination algorithm for two-phase PIV employs second-order intensity gradients to identify objects. Then, the objects are sorted into solids and tracers according to parametric combinations of size and brightness. Solids velocities are computed by tracking, gas velocities by cross-correlation. Tests in a fully-developed turbulent channel flow of air showed that the two phases do not contaminate or bias each other's velocity statistics. Error magnitude and valid data yield were quantified with artificial images for three particle sizes (25, 33, and 63 {mu}m), two interrogation area sizes (32 and 64 pixels), and volumetric solids loads from 0.0022% to 0.014%. At the channel centerline, the gas valid data yield was above 98% and the RMS error in gas velocity was less than 0.1 pixels for all variations of these parameters. The solid-to-tracer signal ratio was found to be the major parameter affecting the magnitude of the RMS error. (orig.)

  18. Effects of crystal size on the mechanical properties of a lithium disilicate glass-ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Li, D. [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, 28 West Xianning Road, Xi’an 710049 (China); Guo, J.W.; Wang, X.S; Zhang, S.F. [State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, 145 West Changle Road, Xi’an 710032 (China); He, L., E-mail: helin@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, 28 West Xianning Road, Xi’an 710049 (China)

    2016-07-04

    Crystal size of lithium disilicate (LD) phase in a LD glass-ceramic was changed by thermally controlled crystallization of a precursory LD glass at different temperatures. Effects of the crystal size on the mechanical properties of the glass-ceramic were investigated. It was found that the flexural strength presented a hump-like variation trend with increasing the crystal size, the hardness monotonously decreased at the same time. It was further confirmed that micro residual compressive stresses existed inside the LD crystals due to the thermal expansion mismatch between the glass matrix and the crystalline phase. The levels of the residual stresses increased with increasing the crystal size. The crystal size performed dual effects on the flexural strength of the glass-ceramic: an “interlocking effect” caused by larger-sized LD crystals and a “micro residual stress effect” related to the balancing tensile stresses in the glass matrix. Higher residual tensile stresses in the glass matrix induced by larger-sized LD crystals would counteract the “interlocking effect” of the crystals, causing the strength degradation. The hardness of the glass-ceramic was mainly controlled by the “micro residual stress effect”.

  19. Micron size GMR magnetic sensor with needle structure

    Science.gov (United States)

    Yamada, S.; Haraszczuk, R.; Kakikawa, M.; Hoang, H.

    2012-05-01

    The work presents inimitable shaped needle type probe with spin valve giant magnetoresistance (SV-GMR) elements. Sensitive elements with 75 μm width are connected in the Wheatstone bridge structure. The length of the needle is 20-30 mm and its cross section is square. The magnetic sensor probe has the advantage of micron order spatial resolution. The needle type probe works as a gradient meter which concurrently suppresses the influence of externally applied field and detects magnetic fields emanating from nano or micro order size sources. Sensing elements present high sensitivity 260 μV/μT and are capable of detecting the magnetic fields in order of few nT. SV-GMR elements present flat amplitude and phase characteristics in wide frequency range. The novel characteristicsof the probe allow it to be utilized in detection of the in-phase and out of phase signal components. An additional merit of this design is extremely small liftoff height between sensing element and the source of magnetic field. The SV-GMR elements are isolated only by very thin protection layer (a few μm), that gives opportunity to apply the probe in biological (in vivo) experiments, and in non destructive evaluation of current detection. The needle shape allows the sensing element toapproach the examined materials in a distance of few ten μm.

  20. Size-exclusion chromatographic NMR under HR-MAS.

    Science.gov (United States)

    Lucena Alcalde, Guillermo; Anderson, Natalie; Day, Iain J

    2017-05-01

    The addition of stationary phases or sample modifiers can be used to modify the separation achievable in the diffusion domain of diffusion NMR experiments or provide information on the nature of the analyte-sample modifier interaction. Unfortunately, the addition of insoluble chromatographic stationary phases can lead to line broadening and degradation in spectral resolution, largely because of differences in magnetic susceptibility between the sample and the stationary phase. High-resolution magic angle spinning (HR-MAS) techniques can be used to remove this broadening. Here, we attempt the application of HR-MAS to size-exclusion chromatographic NMR with limited success. Observed diffusion coefficients for polymer molecular weight reference standards are shown to be larger than those obtained on static samples. Further investigation reveals that under HR-MAS it is possible to obtain reasonably accurate estimates of diffusion coefficients, using either full rotor synchronisation or sophisticated pulse sequences. The requirement for restricting the sample to the centre of the MAS rotor to ensure homogeneous magnetic and RF fields is also tested. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Fast phase processing in off-axis holography by CUDA including parallel phase unwrapping.

    Science.gov (United States)

    Backoach, Ohad; Kariv, Saar; Girshovitz, Pinhas; Shaked, Natan T

    2016-02-22

    We present parallel processing implementation for rapid extraction of the quantitative phase maps from off-axis holograms on the Graphics Processing Unit (GPU) of the computer using computer unified device architecture (CUDA) programming. To obtain efficient implementation, we parallelized both the wrapped phase map extraction algorithm and the two-dimensional phase unwrapping algorithm. In contrast to previous implementations, we utilized unweighted least squares phase unwrapping algorithm that better suits parallelism. We compared the proposed algorithm run times on the CPU and the GPU of the computer for various sizes of off-axis holograms. Using the GPU implementation, we extracted the unwrapped phase maps from the recorded off-axis holograms at 35 frames per second (fps) for 4 mega pixel holograms, and at 129 fps for 1 mega pixel holograms, which presents the fastest processing framerates obtained so far, to the best of our knowledge. We then used common-path off-axis interferometric imaging to quantitatively capture the phase maps of a micro-organism with rapid flagellum movements.

  2. A fracture mechanics study of the phase separating planar electrodes: Phase field modeling and analytical results

    Science.gov (United States)

    Haftbaradaran, H.; Maddahian, A.; Mossaiby, F.

    2017-05-01

    It is well known that phase separation could severely intensify mechanical degradation and expedite capacity fading in lithium-ion battery electrodes during electrochemical cycling. Experiments have frequently revealed that such degradation effects could be substantially mitigated via reducing the electrode feature size to the nanoscale. The purpose of this work is to present a fracture mechanics study of the phase separating planar electrodes. To this end, a phase field model is utilized to predict how phase separation affects evolution of the solute distribution and stress profile in a planar electrode. Behavior of the preexisting flaws in the electrode in response to the diffusion induced stresses is then examined via computing the time dependent stress intensity factor arising at the tip of flaws during both the insertion and extraction half-cycles. Further, adopting a sharp-interphase approximation of the system, a critical electrode thickness is derived below which the phase separating electrode becomes flaw tolerant. Numerical results of the phase field model are also compared against analytical predictions of the sharp-interphase model. The results are further discussed with reference to the available experiments in the literature. Finally, some of the limitations of the model are cautioned.

  3. Size-selecting effect of water on fluorescent silicon clusters

    Energy Technology Data Exchange (ETDEWEB)

    Torricelli, G; Akraiam, A; Von Haeften, K, E-mail: kvh6@le.ac.uk [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom)

    2011-08-05

    Silicon clusters were produced by gas aggregation in vacuum and co-deposited with water vapour onto a cold target where the water vapour froze. Melting of the ice yielded fluorescent silicon nanoparticles suspended in water which were investigated by photoluminescence spectroscopy (PL) and atomic force microscopy (AFM). The PL spectrum showed a prominent band at 420 nm and other, less intense bands at shorter wavelengths. No fluorescence was observed below 275 nm. The shortest wavelength observed was related to a silicon cluster diameter of 0.9 nm using a simple particle-in-a-box model. Drops of the suspension were also deposited on freshly cleaved HOPG and investigated by AFM. The images showed single and agglomerated clusters with heights of typically 0.6 up to 2 nm. The sizes displayed by our measurements are not correlated to the average sizes that result from gas aggregation, indicating a size-selecting effect of the water suspension. The cluster-cluster interaction in water is governed by repulsion due to thermal energy and attraction due to van der Waals forces. For very small clusters repulsion dominates; at 3 nm diameter the two forces are balanced. We identify this stable phase of small clusters as the origin of exceptionally stable fluorescence.

  4. EPICS Controlled Collimator for Controlling Beam Sizes in HIPPO

    Energy Technology Data Exchange (ETDEWEB)

    Napolitano, Arthur Soriano [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vogel, Sven C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-03

    Controlling the beam spot size and shape in a diffraction experiment determines the probed sample volume. The HIPPO - High-Pressure-Preferred Orientation– neutron time-offlight diffractometer is located at the Lujan Neutron Scattering Center in Los Alamos National Laboratories. HIPPO characterizes microstructural parameters, such as phase composition, strains, grain size, or texture, of bulk (cm-sized) samples. In the current setup, the beam spot has a 10 mm diameter. Using a collimator, consisting of two pairs of neutron absorbing boron-nitride slabs, horizontal and vertical dimensions of a rectangular beam spot can be defined. Using the HIPPO robotic sample changer for sample motion, the collimator would enable scanning of e.g. cylindrical samples along the cylinder axis by probing slices of such samples. The project presented here describes implementation of such a collimator, in particular the motion control software. We utilized the EPICS (Experimental Physics Interface and Control System) software interface to integrate the collimator control into the HIPPO instrument control system. Using EPICS, commands are sent to commercial stepper motors that move the beam windows.

  5. Preliminary Correlations for Remotely Piloted Aircraft Systems Sizing

    Directory of Open Access Journals (Sweden)

    Álvaro Gómez-Rodríguez

    2018-01-01

    Full Text Available The field of Remotely Piloted Aircraft Systems (RPAS is currently undergoing a noteworthy expansion. The diverse types of missions that these aircraft can accomplish, both in military and civil environments, have motivated an increase of interest in their study and applications. The methods chosen to develop this study are based on the statistical analysis of a database including numerous models of RPAS and the estimation of different correlations in order to develop a design method for rapid sizing of H-tail RPAS. Organizing the information of the database according to relevant characteristics, information relative to the state-of-the-art design tendencies can be extracted, which can serve to take decisions relative to the aerodynamic configuration or the power plant in the first phases of the design project. Furthermore, employing statistical correlations estimated from the database, a design method for rapid-sizing of H-tail RPAS has been conducted, which will be focused on the sizing of the wing and tail surfaces. The resulting method has been tested by applying it to an example case so as to validate the proposed procedure.

  6. Dynamic phase extraction in phase-shifted shearography

    Science.gov (United States)

    Hou, Yuanyuan; Xu, Jiancheng

    2016-03-01

    Phase-shifted shearography needs to extract dynamic phase of the measured object after loading, so an algorithm for dynamic phase extraction in phase-shifted shearography is proposed to analyze the speckle patterns with random phase shifts. By using correlation method, the fringe patterns with random phase shifts are obtained from the speckle patterns with random phase shifts. Then the dynamic phase distributions are extracted from one set of random phase-shifted fringe patterns by principle component analysis. The experimental results show that the extracted phases are accurate and efficient. The proposed method is non-iterative and has no strict requirement for the spatial-carrier frequency of fringe patterns, so it is suitable for dynamic shearing speckle interferometry.

  7. Giant Galaxy Messier 87 finally sized up

    Science.gov (United States)

    2009-05-01

    Using ESO's Very Large Telescope, astronomers have succeeded in measuring the size of giant galaxy Messier 87 and were surprised to find that its outer parts have been stripped away by still unknown effects. The galaxy also appears to be on a collision course with another giant galaxy in this very dynamic cluster. ESO PR Photo 19a/09 The Intercluster Light ESO PR Photo 19b/09 Intergalactic Planetary Nebulae ESO PR Photo 19c/09 The Virgo Cluster The new observations reveal that Messier 87's halo of stars has been cut short, with a diameter of about a million light-years, significantly smaller than expected, despite being about three times the extent of the halo surrounding our Milky Way [1]. Beyond this zone only few intergalactic stars are seen. "This is an unexpected result," says co-author Ortwin Gerhard. "Numerical models predict that the halo around Messier 87 should be several times larger than our observations have revealed. Clearly, something must have cut the halo off early on." The team used FLAMES, the super-efficient spectrograph at ESO's Very Large Telescope at the Paranal Observatory in Chile, to make ultra-precise measurements of a host of planetary nebulae in the outskirts of Messier 87 and in the intergalactic space within the Virgo Cluster of galaxies, to which Messier 87 belongs. FLAMES can simultaneously take spectra many sources, spread over an area of the sky about the size of the Moon. The new result is quite an achievement. The observed light from a planetary nebula in the Virgo Cluster is as faint as that from a 30-Watt light bulb at a distance of about 6 million kilometres (about 15 times the Earth-Moon distance). Furthermore, planetary nebulae are thinly spread through the cluster, so even FLAMES's wide field of view could only capture a few tens of nebulae at a time. "It is a little bit like looking for a needle in a haystack, but in the dark", says team member Magda Arnaboldi. "The FLAMES spectrograph on the VLT was the best instrument

  8. Size characterization of inclusion bodies by sedimentation field-flow fractionation

    Science.gov (United States)

    Margreiter, Gerd; Messner, Paul; Caldwell, Karin D.; Bayer, Karl

    2015-01-01

    Sedimentation field-flow fractionation (sedFFF) was evaluated to characterize the size of Δ(4–23)TEM-β-lactamase inclusion bodies (IBs) overexpressed in fed-batch cultivations of Escherichia coli. Heterologous Δ(4–23)TEM-β-lactamase protein formed different sizes of IBs, depending upon the induction conditions. In the early phases of recombinant protein expression, induced with low concentrations of IPTG (isopropyl-β-d-thiogalactoside), IB masses were larger than expected and showed heterogeneous size distributions. During cultivation, IB sizes showed a Gaussian distribution and reached a broad range by the end of the fed-batch cultivations. The obtained result proved the aptitude of sedFFF to rapidly assess the size distribution of IBs in a culture. PMID:18760314

  9. The effect of precursor powder size on the microstructure and integranular properties of Bi2223 superconductors

    Directory of Open Access Journals (Sweden)

    I. Abdolhosseini

    2006-09-01

    Full Text Available  We have studied the effect of precursor powder size on the microstructure and intergranular behavior of polycrystalline Bi2223 superconductors using the XRD, SEM, electrical resistivity and AC susceptibility techniques. Polycrystalline Bi2223 superconductors were prepared from the powders with different milling times. The XRD results show that by decreasing the precursor powder size the Bi2223 phase fraction increases. It was found that the grain size and grain connectivity improved by decreasing the precursor powder size. Analysis of the temperature dependence of the AC susceptibility near the transition temperature (Tc has been done employing Beans critical state model. The observed variation of intergranular critical current densities (Jc with temperature indicates that the decreasing of precursor powder size in the Bi2223 system cases an increase in the intergranular critical current density.

  10. Effects of oil and drug concentrations on droplets size of palm oil esters (POEs) nanoemulsion.

    Science.gov (United States)

    Sakeena, M H F; Elrashid, S M; Munavvar, A S; Azmin, M N

    2011-01-01

    Aim of the present work is to study the effects of oil and drug concentrations on droplets size of a nanoemulsion. Newly introduced oil, palm oil esters (POEs) by Universiti Putra Malaysia researchers was selected for the oil phase of the nanoemulsion, because the oil was reported to be a good vehicle for pharmaceutical use. Nanoemulsions were prepared with different concentrations of oil and drug and their effects on droplets size were studied by laser scattering spectroscopy (Nanophox). The results of droplets size analysis shows the droplets size increase with increasing concentration of oil and drug concentrations. It can be concluded from this study, that oil and drug concentrations have an effect on the droplets size of POEs nanoemulsion system.

  11. Hydride formation thermodynamics and hysteresis in individual Pd nanocrystals with different size and shape.

    Science.gov (United States)

    Syrenova, Svetlana; Wadell, Carl; Nugroho, Ferry A A; Gschneidtner, Tina A; Diaz Fernandez, Yuri A; Nalin, Giammarco; Świtlik, Dominika; Westerlund, Fredrik; Antosiewicz, Tomasz J; Zhdanov, Vladimir P; Moth-Poulsen, Kasper; Langhammer, Christoph

    2015-12-01

    Physicochemical properties of nanoparticles may depend on their size and shape and are traditionally assessed in ensemble-level experiments, which accordingly may be plagued by averaging effects. These effects can be eliminated in single-nanoparticle experiments. Using plasmonic nanospectroscopy, we present a comprehensive study of hydride formation thermodynamics in individual Pd nanocrystals of different size and shape, and find corresponding enthalpies and entropies to be nearly size- and shape-independent. The hysteresis observed is significantly wider than in bulk, with details depending on the specifics of individual nanoparticles. Generally, the absorption branch of the hysteresis loop is size-dependent in the sub-30 nm regime, whereas desorption is size- and shape-independent. The former is consistent with a coherent phase transition during hydride formation, influenced kinetically by the specifics of nucleation, whereas the latter implies that hydride decomposition either occurs incoherently or via different kinetic pathways.

  12. Evaluating the role of genome downsizing and size thresholds from genome size distributions in angiosperms.

    Science.gov (United States)

    Zenil-Ferguson, Rosana; Ponciano, José M; Burleigh, J Gordon

    2016-07-01

    Whole-genome duplications (WGDs) can rapidly increase genome size in angiosperms. Yet their mean genome size is not correlated with ploidy. We compared three hypotheses to explain the constancy of genome size means across ploidies. The genome downsizing hypothesis suggests that genome size will decrease by a given percentage after a WGD. The genome size threshold hypothesis assumes that taxa with large genomes or large monoploid numbers will fail to undergo or survive WGDs. Finally, the genome downsizing and threshold hypothesis suggests that both genome downsizing and thresholds affect the relationship between genome size means and ploidy. We performed nonparametric bootstrap simulations to compare observed angiosperm genome size means among species or genera against simulated genome sizes under the three different hypotheses. We evaluated the hypotheses using a decision theory approach and estimated the expected percentage of genome downsizing. The threshold hypothesis improves the approximations between mean genome size and simulated genome size. At the species level, the genome downsizing with thresholds hypothesis best explains the genome size means with a 15% genome downsizing percentage. In the genus level simulations, the monoploid number threshold hypothesis best explains the data. Thresholds of genome size and monoploid number added to genome downsizing at species level simulations explain the observed means of angiosperm genome sizes, and monoploid number is important for determining the genome size mean at the genus level. © 2016 Botanical Society of America.

  13. Determination of the optimal sample size for a clinical trial accounting for the population size

    Science.gov (United States)

    Miller, Frank; Day, Simon; Hee, Siew Wan; Madan, Jason; Zohar, Sarah; Posch, Martin

    2016-01-01

    The problem of choosing a sample size for a clinical trial is a very common one. In some settings, such as rare diseases or other small populations, the large sample sizes usually associated with the standard frequentist approach may be infeasible, suggesting that the sample size chosen should reflect the size of the population under consideration. Incorporation of the population size is possible in a decision‐theoretic approach either explicitly by assuming that the population size is fixed and known, or implicitly through geometric discounting of the gain from future patients reflecting the expected population size. This paper develops such approaches. Building on previous work, an asymptotic expression is derived for the sample size for single and two‐arm clinical trials in the general case of a clinical trial with a primary endpoint with a distribution of one parameter exponential family form that optimizes a utility function that quantifies the cost and gain per patient as a continuous function of this parameter. It is shown that as the size of the population, N, or expected size, N∗ in the case of geometric discounting, becomes large, the optimal trial size is O(N1/2) or O(N∗1/2). The sample size obtained from the asymptotic expression is also compared with the exact optimal sample size in examples with responses with Bernoulli and Poisson distributions, showing that the asymptotic approximations can also be reasonable in relatively small sample sizes. PMID:27184938

  14. The size effect in metal cutting

    Indian Academy of Sciences (India)

    When metal is removed by machining there is substantial increase in the specific energy required with decrease in chip size. It is generally believed this is due to the fact that all metals contain defects (grain boundaries, missing and impurity atoms, etc.), and when the size of the material removed decreases, the probability of ...

  15. Researcher Perspectives on Class Size Reduction

    Science.gov (United States)

    Graue, Elizabeth; Rauscher, Erica

    2009-01-01

    This article applies to class size research Grant and Graue's (1999) position that reviews of research represent conversations in the academic community. By extending our understanding of the class size reduction conversation beyond published literature to the perspectives of researchers who have studied the topic, we create a review that includes…

  16. Birth order, family size and educational attainment

    NARCIS (Netherlands)

    de Haan, M.

    2010-01-01

    This paper investigates the effect of family size and birth order on educational attainment. An instrumental variables approach is used to identify the effect of family size. Instruments for the number of children are twins at last birth and the sex mix of the first two children. The effect of birth

  17. Gender based disruptive selection maintains body size ...

    Indian Academy of Sciences (India)

    2014-07-04

    Jul 4, 2014 ... Darwinian fitness in holometabolous insects like the fruit fly Drosophila melanogaster is reported to be positively correlated with body size. If large individuals in a population have higher fitness, then one would expect directional selection to operate leading to uniformly large individuals. However, size ...

  18. Visuomotor Dissociation in Cerebral Scaling of Size

    NARCIS (Netherlands)

    Potgieser, Adriaan R. E.; de Jong, Bauke M.

    2016-01-01

    Estimating size and distance is crucial in effective visuomotor control. The concept of an internal coordinate system implies that visual and motor size parameters are scaled onto a common template. To dissociate perceptual and motor components in such scaling, we performed an fMRI experiment in

  19. Size and support ratings of US banks

    NARCIS (Netherlands)

    Poghosyan, Tigran; Werger, Charlotte; de Haan, Jakob

    We examine whether Fitch support ratings of US banks depend on bank size. Using quarterly data for the period 2004:Q4 to 2012:Q4 and controlling for several factors that make large and small banks different, we find that bank size is positively related to support ratings. However, the effect is

  20. Bubble Size Distributions in Coastal Seas

    NARCIS (Netherlands)

    Leeuw, G. de; Cohen, L.H.

    1995-01-01

    Bubble size distributions have been measured with an optical system that is based on imaging of a small sample volume with a CCD camera system, and processing of the images to obtain the size of individual bubbles in the diameter range from 30 to lOOO^m. This bubble measuring system is deployed from

  1. Estimating software development project size, using probabilistic ...

    African Journals Online (AJOL)

    This paper describes the quantitative process of managing the size of software development projects by Purchasers (Clients) and Vendors (Development Houses) where there are no historical databases. Probabilistic approach was used to estimate the software project size, using the data collected when we developed a ...

  2. A sub-Mercury-sized exoplanet

    NARCIS (Netherlands)

    Barclay, T.; et al., [Unknown; Hekker, S.

    2013-01-01

    Since the discovery of the first exoplanets1, 2, it has been known that other planetary systems can look quite unlike our own3. Until fairly recently, we have been able to probe only the upper range of the planet size distribution4, 5, and, since last year, to detect planets that are the size of

  3. Body Size Distribution of the Dinosaurs

    Science.gov (United States)

    O’Gorman, Eoin J.; Hone, David W. E.

    2012-01-01

    The distribution of species body size is critically important for determining resource use within a group or clade. It is widely known that non-avian dinosaurs were the largest creatures to roam the Earth. There is, however, little understanding of how maximum species body size was distributed among the dinosaurs. Do they share a similar distribution to modern day vertebrate groups in spite of their large size, or did they exhibit fundamentally different distributions due to unique evolutionary pressures and adaptations? Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups. We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations. We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates. This pattern is not solely an artefact of bias in the fossil record, as demonstrated by contrasting distributions in two major extinct groups and supports the hypothesis that dinosaurs exhibited a fundamentally different life history strategy to other terrestrial vertebrates. A disparity in the size distribution of the herbivorous Ornithischia and Sauropodomorpha and the largely carnivorous Theropoda suggests that this pattern may have been a product of a divergence in evolutionary strategies: herbivorous dinosaurs rapidly evolved large size to escape predation by carnivores and maximise digestive efficiency; carnivores had sufficient resources among juvenile dinosaurs and non-dinosaurian prey to achieve optimal success at smaller body size. PMID:23284818

  4. Board Size Effects in Closely Held Corporations

    DEFF Research Database (Denmark)

    Bennedsen, Morten; Kongsted, H.C.; Meisner Nielsen, Kasper

    2004-01-01

    Previous work on board size effects in closely held corporationshas established a negative correlation between board size and firm performance.We argue that this work has been incomplete in analysing the causalrelationship due to lack of ownership information and weak identificationstrategies...

  5. Additional Considerations in Determining Sample Size.

    Science.gov (United States)

    Levin, Joel R.; Subkoviak, Michael J.

    Levin's (1975) sample-size determination procedure for completely randomized analysis of variance designs is extended to designs in which antecedent or blocking variables information is considered. In particular, a researcher's choice of designs is framed in terms of determining the respective sample sizes necessary to detect specified contrasts…

  6. Determining Sample Size for Research Activities

    Science.gov (United States)

    Krejcie, Robert V.; Morgan, Daryle W.

    1970-01-01

    A formula for determining sample size, which originally appeared in 1960, has lacked a table for easy reference. This article supplies a graph of the function and a table of values which permits easy determination of the size of sample needed to be representative of a given population. (DG)

  7. Interteaching: Discussion Group Size and Course Performance

    Science.gov (United States)

    Truelove, Jacob C.; Saville, Bryan K.; Van Patten, Ryan

    2013-01-01

    Researchers have yet to examine whether discussion group size affects student performance in an interteaching-based course. In the current study, we addressed this question by manipulating discussion group size (smaller groups of 2 students vs. larger groups of 4 students) across 2 sections of an undergraduate psychology course. We found no…

  8. Size Matters, if you Control Your Junk

    DEFF Research Database (Denmark)

    Asness, Cliff; Frazzini, Andrea; Israel, Ronen

    The size premium has been challenged along many fronts: it has a weak historical record, varies significantly over time, in particular weakening after its discovery, is concentrated among microcap stocks, resides predominantly in January, is not present for non-price based measures of size, is we...

  9. Signature Size: A Key to Status Awareness

    Science.gov (United States)

    Zweigenhaft, Richard L.

    1970-01-01

    Hypothesizing that signature size is related to status, signatures of undergraduates, blue collar workers, and professors were compared and found to be ranked in the above order. Further, case studies of professors revealed a 50 percent increase in size of signature from several months prior to attainment of the Ph. D. to four years afterward. (DB)

  10. Birth Order, Family Size and Educational Attainment

    Science.gov (United States)

    de Haan, Monique

    2010-01-01

    This paper investigates the effect of family size and birth order on educational attainment. An instrumental variables approach is used to identify the effect of family size. Instruments for the number of children are twins at last birth and the sex mix of the first two children. The effect of birth order is identified, by examining the relation…

  11. The average size of ordered binary subgraphs

    NARCIS (Netherlands)

    van Leeuwen, J.; Hartel, Pieter H.

    To analyse the demands made on the garbage collector in a graph reduction system, the change in size of an average graph is studied when an arbitrary edge is removed. In ordered binary trees the average number of deleted nodes as a result of cutting a single edge is equal to the average size of a

  12. The size effect in metal cutting

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    The size effect in metal cutting. MILTON C SHAW. Emeritus Professor of Engineering, Arizona State University, Tempe AZ,. 85287-6106, USA. Abstract. When metal is removed by machining there is substantial increase in the specific energy required with decrease in chip size. It is generally believed this is due to the fact ...

  13. Towards traceable size determination of extracellular vesicles

    NARCIS (Netherlands)

    Varga, Zoltán; Yuana, Yuana; Grootemaat, Anita E.; van der Pol, Edwin; Gollwitzer, Christian; Krumrey, Michael; Nieuwland, Rienk

    2014-01-01

    Extracellular vesicles (EVs) have clinical importance due to their roles in a wide range of biological processes. The detection and characterization of EVs are challenging because of their small size, low refractive index, and heterogeneity. In this manuscript, the size distribution of an

  14. Body size distribution of the dinosaurs.

    Science.gov (United States)

    O'Gorman, Eoin J; Hone, David W E

    2012-01-01

    The distribution of species body size is critically important for determining resource use within a group or clade. It is widely known that non-avian dinosaurs were the largest creatures to roam the Earth. There is, however, little understanding of how maximum species body size was distributed among the dinosaurs. Do they share a similar distribution to modern day vertebrate groups in spite of their large size, or did they exhibit fundamentally different distributions due to unique evolutionary pressures and adaptations? Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups. We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations. We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates. This pattern is not solely an artefact of bias in the fossil record, as demonstrated by contrasting distributions in two major extinct groups and supports the hypothesis that dinosaurs exhibited a fundamentally different life history strategy to other terrestrial vertebrates. A disparity in the size distribution of the herbivorous Ornithischia and Sauropodomorpha and the largely carnivorous Theropoda suggests that this pattern may have been a product of a divergence in evolutionary strategies: herbivorous dinosaurs rapidly evolved large size to escape predation by carnivores and maximise digestive efficiency; carnivores had sufficient resources among juvenile dinosaurs and non-dinosaurian prey to achieve optimal success at smaller body size.

  15. Understanding animal group-size distributions.

    Directory of Open Access Journals (Sweden)

    Michael Griesser

    Full Text Available One of the most striking aspects of animal groups is their remarkable variation in size, both within and between species. While a number of mechanistic models have been proposed to explain this variation, there are few comprehensive datasets against which these models have been tested. In particular, we only vaguely understand how environmental factors and behavioral activities affect group-size distributions. Here we use observations of House sparrows (Passer domesticus to investigate the factors determining group-size distribution. Over a wide range of conditions, we observed that animal group sizes followed a single parameter distribution known as the logarithmic distribution. This single parameter is the mean group size experienced by a randomly chosen individual (including the individual itself. For sparrows, the experienced mean group size, and hence the distribution, was affected by four factors: morning temperature, place, behavior and the degree of food spillage. Our results further indicate that the sparrows regulate the mean group size they experience, either by groups splitting more or merging less when local densities are high. We suggest that the mean experienced group size provides a simple but general tool for assessing the ecology and evolution of grouping.

  16. MICRON-SIZED POLYMER PARTICLES FROM TANZANIAN ...

    African Journals Online (AJOL)

    Micron sized polymeric particles were prepared from cashew nut shell liquid and subsequently functionalized to produce micron-sized carboxylated cation exchange resin (MCCER). By titrimetry and analytical procedures employing atomic absorption spectrometry, an assessment of the cation exchange capability of the ...

  17. Phase transitions in restricted Boltzmann machines with generic priors

    Science.gov (United States)

    Barra, Adriano; Genovese, Giuseppe; Sollich, Peter; Tantari, Daniele

    2017-10-01

    We study generalized restricted Boltzmann machines with generic priors for units and weights, interpolating between Boolean and Gaussian variables. We present a complete analysis of the replica symmetric phase diagram of these systems, which can be regarded as generalized Hopfield models. We underline the role of the retrieval phase for both inference and learning processes and we show that retrieval is robust for a large class of weight and unit priors, beyond the standard Hopfield scenario. Furthermore, we show how the paramagnetic phase boundary is directly related to the optimal size of the training set necessary for good generalization in a teacher-student scenario of unsupervised learning.

  18. Solid Phase versus Solution Phase Synthesis of Heterocyclic Macrocycles

    OpenAIRE

    McAlpine, Shelli R.; Seong Jong Kim

    2013-01-01

    Comparing a solution phase route to a solid phase route in the synthesis of the cytotoxic natural product urukthapelstatin A (Ustat A) confirmed that a solid phase method is superior. The solution phase approach was tedious and involved cyclization of a ridged heterocyclic precursor, while solid phase allowed the rapid generation of a flexible linear peptide. Cyclization of the linear peptide was facile and subsequent generation of three oxazoles located within the structure of Ustat A proved...

  19. Theory of alloy phases

    Energy Technology Data Exchange (ETDEWEB)

    Watson, R.E.; Ehrenreich, H.; Bennett, L.H.

    1977-01-01

    Various non-thermodynamic approaches to understanding and predicting phase diagrams are explored from the viewpoint of solid-state physics. The review is intended to indicate the scope of activity and some of the progress which has been made. (GHT)

  20. Many Phases of Carbon

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 12. Many Phases of Carbon. B Gopalakrishnan S V Subramanyam. General Article Volume 7 Issue 12 December 2002 pp 10-19. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/007/12/0010-0019 ...