WorldWideScience

Sample records for envelope velocity evolution

  1. Common envelope evolution

    NARCIS (Netherlands)

    Taam, Ronald E.; Ricker, Paul M.

    2010-01-01

    The common envelope phase of binary star evolution plays a central role in many evolutionary pathways leading to the formation of compact objects in short period systems. Using three dimensional hydrodynamical computations, we review the major features of this evolutionary phase, focusing on the

  2. 14 CFR 29.87 - Height-velocity envelope.

    Science.gov (United States)

    2010-01-01

    ... Category A engine isolation requirements, the height-velocity envelope for complete power failure must be... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Height-velocity envelope. 29.87 Section 29... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.87 Height-velocity envelope. (a...

  3. Evolution of envelope solitons of ionization waves

    International Nuclear Information System (INIS)

    Ohe, K.; Hashimoto, M.

    1985-01-01

    The time evolution of a particle-like envelope soliton of ionization waves in plasma was investigated theoretically. The hydrodynamic equations of one spatial dimension were solved and the nonlinear dispersion relation was derived. For the amplitude of the wave the nonlinear Schroedinger equation was derived. Its soliton solution was interpreted as the envelope soliton which was experimentally found. The damping rate of the envelope soliton was estimated. (D.Gy.)

  4. Velocity structure of protostellar envelopes: gravitational collapse and rotation

    International Nuclear Information System (INIS)

    Belloche, Arnaud

    2002-01-01

    Stars form from the gravitational collapse of pre-stellar condensations in molecular clouds. The major aim of this thesis is to compare the predictions of collapse models with observations of both very young (class 0) protostars and starless condensations in millimeter molecular lines. We wish to understand what determines the masses of forming stars and whether the initial conditions have an effect on the dynamical evolution of a condensation. Using a Monte-Carlo radiative transfer code, we analyze rotation and infall spectroscopic signatures to study the velocity structure of a sample of protostellar condensations. We show that the envelope of the class 0 protostar IRAM 04191 in the Taurus molecular cloud is undergoing both extended, subsonic infall and fast, differential rotation. We propose that the inner part of the envelope is a magnetically supercritical core in the process of decoupling from the ambient cloud still supported by the magnetic field. We suggest that the kinematical properties observed for IRAM 04191 are representative of the physical conditions characterizing isolated protostars shortly after point mass formation. On the other hand, a similar study for the pre-stellar condensations of the Rho Ophiuchi proto-cluster yields mass accretion rates that are an order of magnitude higher than in IRAM 04191. This suggests that individual protostellar collapse in clusters is induced by external disturbances. Moreover, we show that the condensations do not have time to orbit significantly through the proto-cluster gas before evolving into protostars and pre-main-sequence stars. This seems inconsistent with models which resort to dynamical interactions and competitive accretion to build up a mass spectrum comparable to the stellar initial mass function. We conclude that protostellar collapse is nearly spontaneous in regions of isolated star formation such as the Taurus cloud but probably strongly induced in proto-clusters. (author) [fr

  5. EVOLUTION OF ROTATIONAL VELOCITIES OF A-TYPE STARS

    International Nuclear Information System (INIS)

    Yang Wuming; Bi Shaolan; Tian Zhijia; Meng Xiangcun

    2013-01-01

    The equatorial velocity of A-type stars undergoes an acceleration in the first third of the main sequence (MS) stage, but the velocity decreases as if the stars were not undergoing any redistribution of angular momentum in the external layers in the last stage of the MS phase. Our calculations show that the acceleration and the decrease of the equatorial velocity can be reproduced by the evolution of the differential rotation zero-age MS model with the angular momentum transport caused by hydrodynamic instabilities during the MS stage. The acceleration results from the fact that the angular momentum stored in the interiors of the stars is transported outward. In the last stage, the core and the radiative envelope are uncoupling, and the rotation of the envelope is a quasi-solid rotation; the uncoupling and the expansion of the envelope indicate that the decrease of the equatorial velocity approximately follows the slope for the change in the equatorial velocity of the model without any redistribution of angular momentum. When the fractional age 0.3 ∼ MS ∼< 0.5, the equatorial velocity remains almost constant for stars whose central density increases with age in the early stage of the MS phase, while the velocity decreases with age for stars whose central density decreases with age in the early stage of the MS phase.

  6. Envelope evolution of a laser pulse in an active medium

    International Nuclear Information System (INIS)

    Fisher, D.L.; Tajima, T.; Downer, M.C.; Siders, C.W.

    1994-11-01

    The authors show that the envelope velocity, v env , of a short laser pulse can, via propagation in an active medium, be made less than, equal to, or even greater than c, the vacuum phase velocity of light. Simulation results, based on moving frame propagation equations coupling the laser pulse, active medium and plasma, are presented, as well as equations that determines the design value of super- and sub-luminous v env . In this simulation the laser pulse evolves in time in a moving frame as opposed to their earlier work where the profile was fixed. The elimination of phase slippage and pump depletion effects in the laser wakefield accelerator is discussed as a particular application. Finally they discuss media properties necessary for an experimental realization of this technique

  7. Helioseismic measurements in the solar envelope using group velocities of surface waves

    Science.gov (United States)

    Vorontsov, S. V.; Baturin, V. A.; Ayukov, S. V.; Gryaznov, V. K.

    2014-07-01

    At intermediate- and high-degree l, solar p and f modes can be considered as surface waves. Using variational principle, we derive an integral expression for the group velocities of the surface waves in terms of adiabatic eigenfunctions of normal modes, and address the benefits of using group-velocity measurements as a supplementary diagnostic tool in solar seismology. The principal advantage of using group velocities, when compared with direct analysis of the oscillation frequencies, comes from their smaller sensitivity to the uncertainties in the near-photospheric layers. We address some numerical examples where group velocities are used to reveal inconsistencies between the solar models and the seismic data. Further, we implement the group-velocity measurements to the calibration of the specific entropy, helium abundance Y, and heavy-element abundance Z in the adiabatically stratified part of the solar convective envelope, using different recent versions of the equation of state. The results are in close agreement with our earlier measurements based on more sophisticated analysis of the solar oscillation frequencies. These results bring further support to the downward revision of the solar heavy-element abundances in recent spectroscopic measurements.

  8. Evolution of a blue supergiant with a neutron star companion immersed in its envelope

    International Nuclear Information System (INIS)

    Delgado, A.J.

    1980-01-01

    The evolution of a binary system consisting of 1 Msub(sun) neutron star and a 25 Msub(sun) blue supergiant through a phase of common envelope is investigated. We include the effects of an additional energy source on the supergiant's envelope, due to the presence of the neutron star, and variable mass loss from the system, taken as proportional to the total luminosity. The results indicate that, independently of the initial period, the system loses its whole envelope as a consequence of the common envelope phase, the final product of this being a detached system, consisting of a neutron star and a helium star. (orig.)

  9. Formation of Low-Mass X-Ray Binaries. II. Common Envelope Evolution of Primordial Binaries with Extreme Mass Ratios

    Science.gov (United States)

    Kalogera, Vassiliki; Webbink, Ronald F.

    1998-01-01

    We study the formation of low-mass X-ray binaries (LMXBs) through helium star supernovae in binary systems that have each emerged from a common envelope phase. LMXB progenitors must satisfy a large number of evolutionary and structural constraints, including survival through common envelope evolution, through the post-common envelope phase, where the precursor of the neutron star becomes a Wolf-Rayet star, and survival through the supernova event. Furthermore, the binaries that survive the explosion must reach interaction within a Hubble time and must satisfy stability criteria for mass transfer. These constraints, imposed under the assumption of a symmetric supernova explosion, prohibit the formation of short-period LMXBs transferring mass at sub-Eddington rates through any channel in which the intermediate progenitor of the neutron star is not completely degenerate. Barring accretion-induced collapse, the existence of such systems therefore requires that natal kicks be imparted to neutron stars. We use an analytical method to synthesize the distribution of nascent LMXBs over donor masses and orbital periods and evaluate their birthrate and systemic velocity dispersion. Within the limitations imposed by observational incompleteness and selection effects, and our neglect of secular evolution in the LMXB state, we compare our results with observations. However, our principal objective is to evaluate how basic model parameters (common envelope ejection efficiency, rms kick velocity, primordial mass ratio distribution) influence these results. We conclude that the characteristics of newborn LMXBs are primarily determined by age and stability constraints and the efficiency of magnetic braking and are largely independent of the primordial binary population and the evolutionary history of LMXB progenitors (except for extreme values of the average kick magnitude or of the common envelope ejection efficiency). Theoretical estimates of total LMXB birthrates are not credible

  10. Evolution of building envelope construction techniques in coastal British Columbia

    Energy Technology Data Exchange (ETDEWEB)

    Mattock, C.; Ito, K.; Oshikawa, T. [International Eco-House Inc., (Canada)

    1999-11-01

    Changes in the significant evolutionary development over the past 3 years in building envelope construction for multi storey wood frame housing in British Columbia are described. The urban areas of this region are characterized by a maritime climate which features a high frequency of wind driven rain and little accumulation of snow. Buildings are exposed to high wetting with little drying potential, and moderate temperatures allow for fungal growth even in the winter. While as in the rest of Canada wetting is often due to condensation of moisture contained in indoor air as it leaks out of the building, in British Columbia wind driven rain is a much larger source of moisture. Given this, the following principles of moisture control have been promoted to the B.C. building industry in order of priority: 1) deflection - using parts and elements of the building such as overhangs and flashings that reduce the exposure of the exterior walls to rain, 2) drainage - using envelope assemblies that will then redirect liquid water to the outside, 3) employing drying elements that promote drying through diffusion such as highly permeable wall sheathings, and 4) use of durable materials - using materials that resist rot such as treated lumber, stainless steel fastenings, etc. A variety of air barrier systems other than the conventional sealed polyethylene approach have been employed because of the introduction of recent building code requirements for enhanced airtightness and air barrier durability combined with the use of rain screen construction. This variety of air barrier systems includes: an airtight drywall, an exterior permeable membrane, and an exterior impermeable membrane.

  11. Non-linear Evolution of the Transverse Instability of Plane-Envelope Solitons

    DEFF Research Database (Denmark)

    Janssen, Peter A. E. M.; Juul Rasmussen, Jens

    1983-01-01

    The nonlinear evolution of the transverse instability of plane envelope soliton solutions of the nonlinear Schrödinger equation is investigated. For the case where the spatial derivatives in the two‐dimensional nonlinear Schrödinger equation are elliptic a critical transverse wavenumber is found...

  12. Evolution of velocity dispersion along cold collisionless flows

    International Nuclear Information System (INIS)

    Banik, Nilanjan; Sikivie, Pierre

    2016-01-01

    We found that the infall of cold dark matter onto a galaxy produces cold collisionless flows and caustics in its halo. If a signal is found in the cavity detector of dark matter axions, the flows will be readily apparent as peaks in the energy spectrum of photons from axion conversion, allowing the densities, velocity vectors and velocity dispersions of the flows to be determined. We also discuss the evolution of velocity dispersion along cold collisionless flows in one and two dimensions. A technique is presented for obtaining the leading behaviour of the velocity dispersion near caustics. The results are used to derive an upper limit on the energy dispersion of the Big Flow from the sharpness of its nearby caustic, and a prediction for the dispersions in its velocity components

  13. Evolution of deformation velocity in narrowing for Zircaloy 2

    Energy Technology Data Exchange (ETDEWEB)

    Cetlin, P R [Minas Gerais Univ., Belo Horizonte (Brazil). Dept. de Engenharia Metalurgica; Okuda, M Y [Goias Univ., Goiania (Brazil). Inst. de Matematica e Fisica

    1980-09-01

    Some studies on the deformation instability in strain shows that the differences in this instability may lead to localized narrowing or elongated narrowing, for Zircaloy-2. The variation of velocity deformation with the narrowing evolution is expected to be different for these two cases. The mentioned variation is discussed, a great difference in behavior having been observed for the case of localized narrowing.

  14. Evolution of semilocal string networks. II. Velocity estimators

    Science.gov (United States)

    Lopez-Eiguren, A.; Urrestilla, J.; Achúcarro, A.; Avgoustidis, A.; Martins, C. J. A. P.

    2017-07-01

    We continue a comprehensive numerical study of semilocal string networks and their cosmological evolution. These can be thought of as hybrid networks comprised of (nontopological) string segments, whose core structure is similar to that of Abelian Higgs vortices, and whose ends have long-range interactions and behavior similar to that of global monopoles. Our study provides further evidence of a linear scaling regime, already reported in previous studies, for the typical length scale and velocity of the network. We introduce a new algorithm to identify the position of the segment cores. This allows us to determine the length and velocity of each individual segment and follow their evolution in time. We study the statistical distribution of segment lengths and velocities for radiation- and matter-dominated evolution in the regime where the strings are stable. Our segment detection algorithm gives higher length values than previous studies based on indirect detection methods. The statistical distribution shows no evidence of (anti)correlation between the speed and the length of the segments.

  15. Common Envelope Evolution: Implications for Post-AGB Stars and Planetary Nebulae

    Science.gov (United States)

    Nordhaus, J.

    2017-10-01

    Common envelopes (CE) are of broad interest as they represent one method by which binaries with initially long-period orbits of a few years can be converted into short-period orbits of a few hours. Despite their importance, the brief lifetimes of CE phases make them difficult to directly observe. Nevertheless, CE interactions are potentially common, can produce a diverse array of nebular shapes, and can accommodate current post-AGB and planetary nebula outflow constraints. Here, I discuss ongoing theoretical and computational work on CEs and speculate on what lies ahead for determining accurate outcomes of this elusive phase of evolution.

  16. VELOCITY EVOLUTION AND THE INTRINSIC COLOR OF TYPE Ia SUPERNOVAE

    International Nuclear Information System (INIS)

    Foley, Ryan J.; Sanders, Nathan E.; Kirshner, Robert P.

    2011-01-01

    To understand how best to use observations of Type Ia supernovae (SNe Ia) to obtain precise and accurate distances, we investigate the relations between spectra of SNe Ia and their intrinsic colors. Using a sample of 1630 optical spectra of 255 SNe, based primarily on data from the CfA Supernova Program, we examine how the velocity evolution and line strengths of Si II λ6355 and Ca II H and K are related to the B – V color at peak brightness. We find that the maximum-light velocity of Si II λ6355 and Ca II H and K and the maximum-light pseudo-equivalent width of Si II λ6355 are correlated with intrinsic color, with intrinsic color having a linear relation with the Si II λ6355 measurements. Ca II H and K does not have a linear relation with intrinsic color, but lower-velocity SNe tend to be intrinsically bluer. Combining the spectroscopic measurements does not improve intrinsic color inference. The intrinsic color scatter is larger for higher-velocity SNe Ia—even after removing a linear trend with velocity—indicating that lower-velocity SNe Ia are more 'standard crayons'. Employing information derived from SN Ia spectra has the potential to improve the measurements of extragalactic distances and the cosmological properties inferred from them.

  17. The evolution of protostellar envelopes of masses 3 Msub(sun) and 10 Msub(sun)

    International Nuclear Information System (INIS)

    Yorke, H.W.

    1979-10-01

    The results of numerical calculations solving the coupled equations of hydrodynamics and radiation transfer are presented in a sequence of papers describing the structure, evolution and appearance of protostellar clouds of intermediate mass (3 Msub(sun) 10 Msub(sun). These numerical calculations begin at the time of initial gravitational collapse and continue through the birth of a central protostar, until the infall of material onto the central object has been reversed. For the 10 M case the formation and evolution of a compact HII region is crudely followed after the gas density in the envelope had decreased sufficiently to allow an ionization front to propagate outwards. For all cases calculated spherical symmetry was assumed. Solar abundances were used. (orig.) 891 WL/orig. 892 RDG

  18. Glimpsing over the event horizon: evolution of nuclear pores and envelope.

    Science.gov (United States)

    Jékely, Gáspár

    2005-02-01

    The origin of eukaryotes from prokaryotic ancestors is one of the major evolutionary transitions in the history of life. The nucleus, a membrane bound compartment for confining the genome, is a central feature of eukaryotic cells and its origin also has to be a central feature of any workable theory that ventures to explain eukaryotic origins. Recent bioinformatic analyses of components of the nuclear pore complex (NPC), the nuclear envelope (NE), and the nuclear transport systems revealed exciting evolutionary connections (e.g., between NPC and coated vesicles) and provided a useful record of the phyletic distribution and history of NPC and NE components. These analyses allow us to refine theories on the origin and evolution of the nucleus, and consequently, of the eukaryotic cell.

  19. Tatooines Future: The Eccentric Response of Keplers Circumbinary Planets to Common-Envelope Evolution of their Host Stars

    Science.gov (United States)

    Kostov, Veselin B.; Moore, Keavin; Tamayo, Daniel; Jayawardhana, Ray; Rinehart, Stephen A.

    2016-01-01

    Inspired by the recent Kepler discoveries of circumbinary planets orbiting nine close binary stars, we explore the fate of the former as the latter evolve off the main sequence. We combine binary star evolution models with dynamical simulations to study the orbital evolution of these planets as their hosts undergo common-envelope stages, losing in the process a tremendous amount of mass on dynamical timescales. Five of the systems experience at least one Roche-lobe overflow and common-envelope stages (Kepler-1647 experiences three), and the binary stars either shrink to very short orbits or coalesce; two systems trigger a double-degenerate supernova explosion. Kepler's circumbinary planets predominantly remain gravitationally bound at the end of the common-envelope phase, migrate to larger orbits, and may gain significant eccentricity; their orbital expansion can be more than an order of magnitude and can occur over the course of a single planetary orbit. The orbits these planets can reach are qualitatively consistent with those of the currently known post-common-envelope, eclipse-time variations circumbinary candidates. Our results also show that circumbinary planets can experience both modes of orbital expansion (adiabatic and non-adiabatic) if their host binaries undergo more than one common-envelope stage; multiplanet circumbinary systems like Kepler-47 can experience both modes during the same common-envelope stage. Additionally, unlike Mercury orbiting the Sun, a circumbinary planet with the same semi-major axis can survive the common envelope evolution of a close binary star with a total mass of 1 Solar Mass.

  20. Accretion Disk Assembly During Common Envelope Evolution: Implications for Feedback and LIGO Binary Black Hole Formation

    Energy Technology Data Exchange (ETDEWEB)

    Murguia-Berthier, Ariadna; Ramirez-Ruiz, Enrico; Antoni, Andrea; Macias, Phillip [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); MacLeod, Morgan, E-mail: armurgui@ucsc.edu [School of Natural Sciences, Institute for Advanced Study, 1 Einstein Drive, Princeton, NJ 08540 (United States)

    2017-08-20

    During a common envelope (CE) episode in a binary system, the engulfed companion spirals to tighter orbital separations under the influence of drag from the surrounding envelope material. As this object sweeps through material with a steep radial gradient of density, net angular momentum is introduced into the flow, potentially leading to the formation of an accretion disk. The presence of a disk would have dramatic consequences for the outcome of the interaction because accretion might be accompanied by strong, polar outflows with enough energy to unbind the entire envelope. Without a detailed understanding of the necessary conditions for disk formation during CE, therefore, it is difficult to accurately predict the population of merging compact binaries. This paper examines the conditions for disk formation around objects embedded within CEs using the “wind tunnel” formalism developed by MacLeod et al. We find that the formation of disks is highly dependent on the compressibility of the envelope material. Disks form only in the most compressible of stellar envelope gas, found in envelopes’ outer layers in zones of partial ionization. These zones are largest in low-mass stellar envelopes, but comprise small portions of the envelope mass and radius in all cases. We conclude that disk formation and associated accretion feedback in CE is rare, and if it occurs, transitory. The implication for LIGO black hole binary assembly is that by avoiding strong accretion feedback, CE interactions should still result in the substantial orbital tightening needed to produce merging binaries.

  1. The Effect of Velocity Correlation on the Spatial Evolution of Breakthrough Curves in Heterogeneous Media

    Science.gov (United States)

    Massoudieh, A.; Dentz, M.; Le Borgne, T.

    2017-12-01

    In heterogeneous media, the velocity distribution and the spatial correlation structure of velocity for solute particles determine the breakthrough curves and how they evolve as one moves away from the solute source. The ability to predict such evolution can help relating the spatio-statistical hydraulic properties of the media to the transport behavior and travel time distributions. While commonly used non-local transport models such as anomalous dispersion and classical continuous time random walk (CTRW) can reproduce breakthrough curve successfully by adjusting the model parameter values, they lack the ability to relate model parameters to the spatio-statistical properties of the media. This in turns limits the transferability of these models. In the research to be presented, we express concentration or flux of solutes as a distribution over their velocity. We then derive an integrodifferential equation that governs the evolution of the particle distribution over velocity at given times and locations for a particle ensemble, based on a presumed velocity correlation structure and an ergodic cross-sectional velocity distribution. This way, the spatial evolution of breakthrough curves away from the source is predicted based on cross-sectional velocity distribution and the connectivity, which is expressed by the velocity transition probability density. The transition probability is specified via a copula function that can help construct a joint distribution with a given correlation and given marginal velocities. Using this approach, we analyze the breakthrough curves depending on the velocity distribution and correlation properties. The model shows how the solute transport behavior evolves from ballistic transport at small spatial scales to Fickian dispersion at large length scales relative to the velocity correlation length.

  2. A Directed Molecular Evolution Approach to Improved Immunogenicity of the HIV-1 Envelope Glycoprotein

    Science.gov (United States)

    Du, Sean X.; Xu, Li; Zhang, Wenge; Tang, Susan; Boenig, Rebecca I.; Chen, Helen; Mariano, Ellaine B.; Zwick, Michael B.; Parren, Paul W. H. I.; Burton, Dennis R.; Wrin, Terri; Petropoulos, Christos J.; Ballantyne, John A.; Chambers, Michael; Whalen, Robert G.

    2011-01-01

    A prophylactic vaccine is needed to slow the spread of HIV-1 infection. Optimization of the wild-type envelope glycoproteins to create immunogens that can elicit effective neutralizing antibodies is a high priority. Starting with ten genes encoding subtype B HIV-1 gp120 envelope glycoproteins and using in vitro homologous DNA recombination, we created chimeric gp120 variants that were screened for their ability to bind neutralizing monoclonal antibodies. Hundreds of variants were identified with novel antigenic phenotypes that exhibit considerable sequence diversity. Immunization of rabbits with these gp120 variants demonstrated that the majority can induce neutralizing antibodies to HIV-1. One novel variant, called ST-008, induced significantly improved neutralizing antibody responses when assayed against a large panel of primary HIV-1 isolates. Further study of various deletion constructs of ST-008 showed that the enhanced immunogenicity results from a combination of effective DNA priming, an enhanced V3-based response, and an improved response to the constant backbone sequences. PMID:21738594

  3. COSMIC EVOLUTION OF SIZE AND VELOCITY DISPERSION FOR EARLY-TYPE GALAXIES

    International Nuclear Information System (INIS)

    Fan, L.; Lapi, A.; Bressan, A.; De Zotti, G.; Danese, L.; Bernardi, M.

    2010-01-01

    Massive (stellar mass M * ∼> 3 x 10 10 M sun ), passively evolving galaxies at redshifts z ∼> 1 exhibit on average physical sizes smaller, by factors ∼3, than local early-type galaxies (ETGs) endowed with the same stellar mass. Small sizes are in fact expected on theoretical grounds, if dissipative collapse occurs. Recent results show that the size evolution at z ∼ 1, where both compact and already extended galaxies are observed and the scatter in size is remarkably larger than it is locally. The presence at high redshift of a significant number of ETGs with the same size as their local counterparts, as well as ETGs with quite small size (∼ H (z). We demonstrate that the projected mass of compact, high-redshift galaxies and that of local ETGs within the same physical radius, the nominal half-luminosity radius of high-redshift ETGs, differ substantially in that the high-redshift ETGs are on average significantly denser. This result suggests that the physical mechanism responsible for the size increase should also remove mass from central galaxy regions (r ∼ 1, we predict the local velocity dispersion distribution function. On comparing it to the observed one, we show that velocity dispersion evolution of massive ETGs is fully compatible with the observed average evolution in size at constant stellar mass. Less massive ETGs (with stellar masses M * ∼ 10 M sun ) are expected to evolve less both in size and in velocity dispersion, because their evolution is essentially determined by supernova feedback, which cannot yield winds as powerful as those triggered by quasars. The differential evolution is expected to leave imprints in the size versus luminosity/mass, velocity dispersion versus luminosity/mass, and central black hole mass versus velocity dispersion relationships, as observed in local ETGs.

  4. Pressure evolution of the high-frequency sound velocity in liquid water

    International Nuclear Information System (INIS)

    Krisch, M.; Sette, F.; D'Astuto, M.; Lorenzen, M.; Mermet, A.; Monaco, G.; Verbeni, R.; Loubeyre, P.; Le Toullec, R.; Ruocco, G.; Cunsolo, A.

    2002-01-01

    The high-frequency sound velocity v ∞ of liquid water has been determined to densities of 1.37 g/cm 3 by inelastic x-ray scattering. In comparison to the hydrodynamic sound velocity v 0 , the increase of v ∞ with density is substantially less pronounced, indicating that, at high density, the hydrogen-bond network is decreasingly relevant to the physical properties of liquid water. Furthermore, we observe an anomaly in v ∞ at densities around 1.12 g/cm 3 , contrasting the smooth density evolution of v 0

  5. Experimental research on time-resolved evolution of cathode plasma expansion velocity in a long pulsed magnetically insulated coaxial diode

    Science.gov (United States)

    Zhu, Danni; Zhang, Jun; Zhong, Huihuang; Ge, Xingjun; Gao, Jingming

    2018-02-01

    Unlike planar diodes, separate research of the axial and radial plasma expansion velocities is difficult for magnetically insulated coaxial diodes. Time-resolved electrical diagnostic which is based on the voltage-ampere characteristics has been employed to study the temporal evolution of the axial and radial cathode plasma expansion velocities in a long pulsed magnetically insulated coaxial diode. Different from a planar diode with a "U" shaped profile of temporal velocity evolution, the temporal evolution trend of the axial expansion velocity is proved to be a "V" shaped profile. Apart from the suppression on the radial expansion velocity, the strong magnetic field is also conducive to slowing down the axial expansion velocity. Compared with the ordinary graphite cathode, the carbon velvet and graphite composite cathode showed superior characteristics as judged by the low plasma expansion velocity and long-term electrical stability as a promising result for applications where long-pulsed and reliable operation at high power is required.

  6. Evolution of planetary nebulae. III. Position-velocity images of butterfly-type nebulae

    International Nuclear Information System (INIS)

    Icke, V.; Preston, H.L.; Balick, B.

    1989-01-01

    Observations of the motions of the shells of the planetary nebulae NGC 2346, NGC 2371-2, NGC 2440, NGC 6058, NGC 6210, IC 1747, IC 5217, J-320, and M2-9 are presented. These are all 'butterfly' type PNs, and show evidence for bipolar shocks. The observations are interpreted in terms of a fast spherical wind, driven by the central star into a quasi-toroidal envelope deposited earlier by the star, during its slow-wind phase on the asymptotic giant branch. It is shown that this model, which is a straightforward extension of a mechanism previously invoked to account for elliptical PNs, reproduces the essential kinematic features of butterfly PNs. It is inferred that the envelopes of butterflies must have a considerable equator-to-pole density gradient, and it is suggested that the origin of this asphericity must be sought in an as yet unknown mechanism during the AGB, Mira, or OH/IR phases of late stellar evolution. 28 references

  7. DISCOVERY, PROGENITOR AND EARLY EVOLUTION OF A STRIPPED ENVELOPE SUPERNOVA iPTF13bvn

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yi; Horesh, Assaf; Kulkarni, S. R. [Astronomy Department, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Kasliwal, Mansi M. [The Observatories, Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Arcavi, Iair; Gal-Yam, Avishay; Gorbikov, Evgeny; Ofek, Eran O.; Yaron, Ofer [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100 (Israel); Hancock, Paul [Sydney Institute for Astronomy (SIfA), School of Physics, The University of Sydney, NSW 2006 (Australia); Valenti, Stefano; Graham, Melissa; Howell, D. Andrew [Las Cumbres Observatory Global Telescope Network, Goleta, CA 93117 (United States); Cenko, S. Bradley [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Sand, David [Department of Physics, Texas Tech University, Lubbock, TX 79409 (United States); Silverman, Jeffrey M.; Wheeler, J. Craig; Marion, G. H. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Walker, Emma S. [Department of Physics, Yale University, New Haven, CT 06511-8499 (United States); Mazzali, Paolo, E-mail: ycao@astro.caltech.edu [INAF-Padova Astronomical Observatory, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); and others

    2013-09-20

    The intermediate Palomar Transient Factory reports our discovery of a young supernova, iPTF13bvn, in the nearby galaxy, NGC 5806 (22.5 Mpc). Our spectral sequence in the optical and infrared suggests a Type Ib classification. We identify a blue progenitor candidate in deep pre-explosion imaging within a 2σ error circle of 80 mas (8.7 pc). The candidate has an M{sub B} luminosity of –5.52 ± 0.39 mag and a B – I color of 0.25 ± 0.25 mag. If confirmed by future observations, this would be the first direct detection for a progenitor of a Type Ib. Fitting a power law to the early light curve, we find an extrapolated explosion date around 0.6 days before our first detection. We see no evidence of shock cooling. The pre-explosion detection limits constrain the radius of the progenitor to be smaller than a few solar radii. iPTF13bvn is also detected in centimeter and millimeter wavelengths. Fitting a synchrotron self-absorption model to our radio data, we find a mass-loading parameter of 1.3×10{sup 12} g cm{sup –1}. Assuming a wind velocity of 10{sup 3} km s{sup –1}, we derive a progenitor mass-loss rate of 3 × 10{sup –5} M {sub ☉} yr{sup –1}. Our observations, taken as a whole, are consistent with a Wolf-Rayet progenitor of the supernova iPTF13bvn.

  8. Evolution of Mass and Velocity Field in the Cosmic Web: Comparison between Baryonic and Dark Matter

    Science.gov (United States)

    Zhu, Weishan; Feng, Long-Long

    2017-03-01

    We investigate the evolution of the cosmic web since z = 5 in grid-based cosmological hydrodynamical simulations, focusing on the mass and velocity fields of both baryonic and cold dark matter. The tidal tensor of density is used as the main method for web identification, with λ th = 0.2-1.2. The evolution trends in baryonic and dark matter are similar, although moderate differences are observed. Sheets appear early, and their large-scale pattern may have been set up by z = 3. In terms of mass, filaments supersede sheets as the primary collapsing structures from z ˜ 2-3. Tenuous filaments assembled with each other to form prominent ones at z dark matter field, and is even moderately stronger between {\\boldsymbol{ω }} and {{\\boldsymbol{e}}}1, and ω and {{\\boldsymbol{e}}}3. Compared with dark matter, there is slightly less baryonic matter found residing in filaments and clusters, and its vorticity developed more significantly below 2-3 Mpc. These differences may be underestimated because of the limited resolution and lack of star formation in our simulation. The impact of the change of dominant structures in overdense regions at z ˜ 2-3 on galaxy formation and evolution is shortly discussed.

  9. Evolution of Proton and Alpha Particle Velocities through the Solar Cycle

    Science.gov (United States)

    Ďurovcová, T.; Šafránková, J.; Němeček, Z.; Richardson, J. D.

    2017-12-01

    Relative properties of solar wind protons and α particles are often used as indicators of a source region on the solar surface, and analysis of their evolution along the solar wind path tests our understanding of physics of multicomponent magnetized plasma. The paper deals with the comprehensive analysis of the difference between proton and α particle bulk velocities at 1 au with a special emphasis on interplanetary coronal mass ejections (ICMEs). A comparison of about 20 years of Wind observations at 1 au with Helios measurements closer to the Sun (0.3-0.7 au) generally confirms the present knowledge that (1) the differential speed between both species increases with the proton speed; (2) the differential speed is lower than the local Alfvén speed; (3) α particles are faster than protons near the Sun, and this difference decreases with the increasing distance. However, we found a much larger portion of observations with protons faster than α particles in Wind than in Helios data and attributed this effect to a preferential acceleration of the protons in the solar wind. A distinct population characterized by a very small differential velocity and nearly equal proton and α particle temperatures that is frequently observed around the maximum of solar activity was attributed to ICMEs. Since this population does not exhibit any evolution with increasing collisional age, we suggest that, by contrast to the solar wind from other sources, ICMEs are born in an equilibrium state and gradually lose this equilibrium due to interactions with the ambient solar wind.

  10. On the evolution of magnetic and velocity fields of an originating sunspot group

    International Nuclear Information System (INIS)

    Bachmann, G.

    1978-01-01

    Magnetographic measurements were made to derive longitudinal magnetic field strengths, line-of-sight velocities and the brightness distribution in an originating sunspot group. These results and photographs of the group are used to compare the evaluation of a relatively simple active region with our present ideas about the evolution of active regions in general. We found that the total magnetic flux increased from about 4 to 20x10 20 Mx over three days. The downward flow of gas in regions with stronger magnetic fields is formed only after the magnetic field has already been bipolar for two days. The maximum velocity always occurred in the main spots of the preceding and the subsequent parts of the sunspot group. Transformation into a flow pattern, which looks like Evershed motion, is observed in the main preceding sunspot after the formation of the penumbra. The generation of new active regions by concentration and amplification of magnetic fields, under the action of supergranulation flow in photospheric layers, cannot play an important role. On the contrary, the behaviour of the active region is in agreement with the conception of rising flux tubes, out of which the gas flows down. Our observations confirm that a magnetic field strength, leading to the generation of sunspots, is attained earlier in the preceding part of the originating active region than in its subsequent part. A series of subflares occurred in the active region, when short-lived small magnetic structure elements emerged in the larger bipolar magnetic field. (author)

  11. Accretion and evolution of ∼2.5 M ⊕ planets with voluminous H/He envelopes

    International Nuclear Information System (INIS)

    Bodenheimer, Peter; Lissauer, Jack J.

    2014-01-01

    Formation of planets in the Neptune size range with low-mass, but voluminous, H 2 /He gaseous envelopes is modeled by detailed numerical simulations according to the core-nucleated accretion scenario. Formation locations ranging from 0.5 to 4 AU from a star of 1 M ☉ are considered. The final planets have heavy-element cores of 2.2-2.5 M ⊕ and envelopes in the range 0.037-0.16 M ⊕ . After the formation process, which lasts 2 Myr or less, the planets evolve at constant mass up to an age of several Gyr. For assumed equilibrium temperatures of 250, 500, and 1000 K, their calculated final radii are compared with those observed by the Kepler spacecraft. For the particular case of Kepler-11 f, we address the question whether it could have formed in situ or whether migration from a formation location farther out in the disk is required.

  12. Building envelope

    CSIR Research Space (South Africa)

    Gibberd, Jeremy T

    2009-01-01

    Full Text Available for use in the building. This is done through photovoltaic and solar water heating panels and wind turbines. Ideally these are integrated in the design of the building envelope to improve the aesthetic quality of the building and minimise material... are naturally ventilated. Renewable energy The building envelope includes renewable energy generation such as photovoltaics, wind turbines and solar water heaters and 10% of the building’s energy requirements are generated from these sources. Views All...

  13. Biomimetic Envelopes

    OpenAIRE

    Ilaria Mazzoleni

    2010-01-01

    How to translate the lessons learned from the analysis and observation of the animal world is the design learning experience presented in this article. Skin is a complex and incredibly sophisticated organ that performs various functions, including protection, sensation and heat and water regulation. In a similar way building envelopes serve multiple roles, as they are the interface between the building inhabitants and environmental elements. The resulting architectural building envelopes prot...

  14. Evolution of the 1963 Vajont landslide (Northern Italy) from low and high velocity friction experiments

    Science.gov (United States)

    Ferri, F.; di Toro, G.; Hirose, T.; Han, R.; Noda, H.; Shimamoto, T.; Pennacchioni, G.

    2009-04-01

    The final slip at about 30 m/s of the Vajont landslide (Northern Italy) on 9th October 1963 was preceded by a long creeping phase which was monitored over about three years. Creep was localized in cm-thick clay-rich (50% Ca-montmorillonite + smectite + illite + vermiculite, 40% calcite and 10% quartz) gouge layers. The velocity results in thermoviscoplastic model of the landslide (Veveakis et al., 2007) suggested that during creep, compaction and frictional heating released water from the clay-rich layer and, by increasing the pore-pressure in the slipping zone, determined the final collapse of the landslide. Here we investigated the frictional evolution of the clay-rich layers and the transition towards the final collapse. Experiments were carried out on the clayey gouge from the slipping zone at atmospheric humidity conditions ("dry") and in the presence of excess water ("saturated"). High velocity friction experiments were performed in a rotary shear apparatus at 1 MPa normal stress (about the normal stress at the sliding surface of the Vajont landslide), velocity v from 0.006 m/s to 1.31 m/s and displacements up to 34 m. The 1 mm-thick clayey gouges were sandwiched between marble cylindrical specimens (24.95 mm in diameter) and confined by Teflon rings to avoid gouge expulsion during the experiments. The fluid release during the experiments was monitored with a humidity sensor. Low velocity friction experiments were performed in a biaxial apparatus at 5 MPa normal stress, v from 1.0 10E-7 m/s to 1.0 10E-4 m/s (within the range at which the slide became critical, 2.0 10E-7 m/s, Veveakis et al., 2007) and displacements up to 0.02 m. In dry experiments, friction is 0.43-0.47 at v Vajont clays), and decreases to 0.03-0.05 at v > 0.006 m/s. At dry conditions, dilatancy was observed for v > 0.7 m/s suggesting fault pressurization by water release due to smectite-to-illite decomposition. Decomposition occurred at temperatures above 300°C, as confirmed by the

  15. Accretion and evolution of ∼2.5 M {sub ⊕} planets with voluminous H/He envelopes

    Energy Technology Data Exchange (ETDEWEB)

    Bodenheimer, Peter [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Lissauer, Jack J., E-mail: peter@ucolick.org, E-mail: Jack.J.Lissauer@nasa.gov [Space Science and Astrobiology Division, NASA-Ames Research Center, Moffett Field, CA 94035 (United States)

    2014-08-20

    Formation of planets in the Neptune size range with low-mass, but voluminous, H{sub 2}/He gaseous envelopes is modeled by detailed numerical simulations according to the core-nucleated accretion scenario. Formation locations ranging from 0.5 to 4 AU from a star of 1 M {sub ☉} are considered. The final planets have heavy-element cores of 2.2-2.5 M {sub ⊕} and envelopes in the range 0.037-0.16 M {sub ⊕}. After the formation process, which lasts 2 Myr or less, the planets evolve at constant mass up to an age of several Gyr. For assumed equilibrium temperatures of 250, 500, and 1000 K, their calculated final radii are compared with those observed by the Kepler spacecraft. For the particular case of Kepler-11 f, we address the question whether it could have formed in situ or whether migration from a formation location farther out in the disk is required.

  16. Defect evolution in cosmology and condensed matter quantitative analysis with the velocity-dependent one-scale model

    CERN Document Server

    Martins, C J A P

    2016-01-01

    This book sheds new light on topological defects in widely differing systems, using the Velocity-Dependent One-Scale Model to better understand their evolution. Topological defects – cosmic strings, monopoles, domain walls or others - necessarily form at cosmological (and condensed matter) phase transitions. If they are stable and long-lived they will be fossil relics of higher-energy physics. Understanding their behaviour and consequences is a key part of any serious attempt to understand the universe, and this requires modelling their evolution. The velocity-dependent one-scale model is the only fully quantitative model of defect network evolution, and the canonical model in the field. This book provides a review of the model, explaining its physical content and describing its broad range of applicability.

  17. Unique Fe2P Nanoparticles Enveloped in Sandwichlike Graphited Carbon Sheets as Excellent Hydrogen Evolution Reaction Catalyst and Lithium-Ion Battery Anode.

    Science.gov (United States)

    Zhang, Yan; Zhang, Huijuan; Feng, Yangyang; Liu, Li; Wang, Yu

    2015-12-09

    The novel Fe2P nanoparticles encapsulated in sandwichlike graphited carbon envelope nanocomposite (Fe2P/GCS) that can be first applied in hydrogen evolution reaction (HER) as well as lithium-ion batteries (LIBs) has been designed and fabricated. The unique sandwiched Fe2P/GCS is characterized with several prominent merits, including large specific surface area, nanoporous structure, excellent electronic conductivity, enhanced structural integrity and so on. All of these endow the Fe2P/GCS with brilliant electrochemical performance. When used as a HER electrocatalyst in acidic media, the harvested Fe2P/GCS demonstrates low onset overpotential and Tafel slope as well as particularly outstanding durability. Moreover, as an anode material for LIBs, the sandwiched Fe2P/GCS presents high specific capacity and excellent cyclability and rate capability. As a consequence, the acquired Fe2P/GCS is a promising material for energy applications, especially HER and LIBs.

  18. Time evolution of scattering states and velocity increase due to nonlinear processes in the quantum hall regime

    International Nuclear Information System (INIS)

    Riess, J.; Duport, C.

    1991-01-01

    We report the first numerical results (with realistic parameter values) for the time evolution of a scattered Landau function in a model system. They give a striking illustration for the Hall velocity increase beyond the classical value of the conduction electrons in the quantum Hall regime. This phenomenon, which is crucial for the integer quantum Hall effect, is caused by a special kind of nonclassical particle dynamics induced by disorder and cannot be described by linear response theory

  19. Slope-Velocity-Equilibrium and evolution of surface roughness on a stony hillslope

    Science.gov (United States)

    Slope-velocity equilibrium is hypothesized as a state that evolves naturally over time due to the interaction between overland flow and bed morphology, wherein steeper areas develop a relative increase in physical and hydraulic roughness such that flow velocity is a unique function of overland flow ...

  20. Strain-dependent Damage Evolution and Velocity Reduction in Fault Zones Induced by Earthquake Rupture

    Science.gov (United States)

    Zhong, J.; Duan, B.

    2009-12-01

    Low-velocity fault zones (LVFZs) with reduced seismic velocities relative to the surrounding wall rocks are widely observed around active faults. The presence of such a zone will affect rupture propagation, near-field ground motion, and off-fault damage in subsequent earth-quakes. In this study, we quantify the reduction of seismic velocities caused by dynamic rup-ture on a 2D planar fault surrounded by a low-velocity fault zone. First, we implement the damage rheology (Lyakhovsky et al. 1997) in EQdyna (Duan and Oglesby 2006), an explicit dynamic finite element code. We further extend this damage rheology model to include the dependence of strains on crack density. Then, we quantify off-fault continuum damage distribution and velocity reduction induced by earthquake rupture with the presence of a preexisting LVFZ. We find that the presence of a LVFZ affects the tempo-spatial distribu-tions of off-fault damage. Because lack of constraint in some damage parameters, we further investigate the relationship between velocity reduction and these damage prameters by a large suite of numerical simulations. Slip velocity, slip, and near-field ground motions computed from damage rheology are also compared with those from off-fault elastic or elastoplastic responses. We find that the reduction in elastic moduli during dynamic rupture has profound impact on these quantities.

  1. Evolution of rotating stars. III. Predicted surface rotation velocities for stars which conserve total angular momentum

    International Nuclear Information System (INIS)

    Endal, A.S.; Sofia, S.

    1979-01-01

    Predicted surface rotation velocities are presented for Population I stars at 10, 7, 5, 3, and 1.5M/sub sun/. The surface velocities have been computed for three different cases of angular momentum redistribution: no radial redistribution (rotation on decoupled shells), complete redistribution (rigid-body rotation), and partial redistribution as predicted by detailed consideration of circulation currents in rotation stars. The velocities for these cases are compared to each other and to observed stellar rotation rates (upsilon sin i).Near the main sequence, rotational effects can substantially reduce the moment of inertia of a star, so nonrotating models consistently underestimate the expected velocities for evolving stars. The magnitude of these effects is sufficient to explain the large numbers of Be stars and, perhaps, to explain the bimodal distribution of velocities observed for the O stars.On the red giant branch, angular momentum redistribution reduces the surface velocity by a factor of 2 or more, relative to the velocity expected for no radial redistribution. This removes the discrepancy between predicted and observed rotation rates for the K giants and makes it unlikely that these stars lose significant amounts of angular momentum by stellar winds. Our calculations indicate that improved observations (by the Fourier-transform technique) of the red giants in the Hyades cluster can be used to determine how angular momentum is redistributed by convection

  2. The Kepler-19 System: A Thick-envelope Super-Earth with Two Neptune-mass Companions Characterized Using Radial Velocities and Transit Timing Variations

    Energy Technology Data Exchange (ETDEWEB)

    Malavolta, Luca; Borsato, Luca; Granata, Valentina; Piotto, Giampaolo; Nascimbeni, Valerio [Dipartimento di Fisica e Astronomia “Galileo Galilei”, Universita’di Padova, Vicolo dell’Osservatorio 3, I-35122 Padova (Italy); Lopez, Eric [SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH93HJ (United Kingdom); Vanderburg, Andrew; Charbonneau, David [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States); Figueira, Pedro [Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, PT4150-762 Porto (Portugal); Mortier, Annelies; Cameron, Andrew Collier [Centre for Exoplanet Science, SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS (United Kingdom); Affer, Laura [INAF—Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90124 Palermo (Italy); Bonomo, Aldo S. [INAF—Osservatorio Astrofisico di Torino, via Osservatorio 20, I-10025 Pino Torinese (Italy); Bouchy, Francois [Observatoire Astronomique de l’Université de Genève, 51 ch. des Maillettes, 1290 Versoix (Switzerland); Buchhave, Lars A. [Centre for Star and Planet Formation, Natural History Museum of Denmark and Niels Bohr Institute, University of Copenhagen, Øster Voldgade 5-7, DK-1350 Copenhagen K (Denmark); Cosentino, Rosario, E-mail: luca.malavolta@unipd.it [INAF—Fundación Galileo Galilei, Rambla José Ana Fernandez Pérez 7, E-38712 Breña Baja (Spain); and others

    2017-05-01

    We report a detailed characterization of the Kepler-19 system. This star was previously known to host a transiting planet with a period of 9.29 days, a radius of 2.2 R {sub ⊕}, and an upper limit on the mass of 20 M {sub ⊕}. The presence of a second, non-transiting planet was inferred from the transit time variations (TTVs) of Kepler-19b over eight quarters of Kepler photometry, although neither the mass nor period could be determined. By combining new TTVs measurements from all the Kepler quarters and 91 high-precision radial velocities obtained with the HARPS-N spectrograph, using dynamical simulations we obtained a mass of 8.4 ± 1.6 M {sub ⊕} for Kepler-19b. From the same data, assuming system coplanarity, we determined an orbital period of 28.7 days and a mass of 13.1 ± 2.7 M {sub ⊕} for Kepler-19c and discovered a Neptune-like planet with a mass of 20.3 ± 3.4 M {sub ⊕} on a 63-day orbit. By comparing dynamical simulations with non-interacting Keplerian orbits, we concluded that neglecting interactions between planets may lead to systematic errors that can hamper the precision in the orbital parameters when the data set spans several years. With a density of 4.32 ± 0.87 g cm{sup −3} (0.78 ± 0.16 ρ {sub ⊕}) Kepler-19b belongs to the group of planets with a rocky core and a significant fraction of volatiles, in opposition to low-density planets characterized only by transit time variations and an increasing number of rocky planets with Earth-like density. Kepler-19 joins the small number of systems that reconcile transit timing variation and radial velocity measurements.

  3. PG 0308 + 096 and PG 1026 + 002 - Two new short period binary stars resulting from common-envelope evolution

    Science.gov (United States)

    Saffer, Rex A.; Wade, Richard A.; Liebert, James; Green, Richard F.; Sion, Edward M.; Bechtold, J.; Foss, Diana; Kidder, K.

    1993-01-01

    Ultraviolet spectroscopy, optical spectroscopy, and spectrophotometry have been used to study the excess UV stars PG 0308 + 096 and PG 1026 + 002. Both objects are short-period binary systems, each containing a DA white dwarf star and a dM star. Orbital periods of approximately 0.284 day for PG 0308 + 096, and aproximately 0.597 day for PG 1026, have been found by spectroscopic analysis of the H-alpha emission line. Ly-alpha and Balmer line profile fitting were used to estimate the mass of white dwarf stars; mass estimates for the dM stars are based on their spectral types. The orbital inclinations are derived from these masses, the periods, and amplitudes of the H-alpha radial velocity curves. The equivalent width of the H-alpha emission line, in each binary system, varies with the orbital phase in such a manner as to imply that it arises, in large part at least, from the hemisphere of the M star that faces the white dwarf star.

  4. Slope-velocity equilibrium and evolution of surface roughness on a stony hillslope

    Science.gov (United States)

    Nearing, Mark A.; Polyakov, Viktor O.; Nichols, Mary H.; Hernandez, Mariano; Li, Li; Zhao, Ying; Armendariz, Gerardo

    2017-06-01

    Slope-velocity equilibrium is hypothesized as a state that evolves naturally over time due to the interaction between overland flow and surface morphology, wherein steeper areas develop a relative increase in physical and hydraulic roughness such that flow velocity is a unique function of overland flow rate independent of slope gradient. This study tests this hypothesis under controlled conditions. Artificial rainfall was applied to 2 m by 6 m plots at 5, 12, and 20 % slope gradients. A series of simulations were made with two replications for each treatment with measurements of runoff rate, velocity, rock cover, and surface roughness. Velocities measured at the end of each experiment were a unique function of discharge rates, independent of slope gradient or rainfall intensity. Physical surface roughness was greater at steeper slopes. The data clearly showed that there was no unique hydraulic coefficient for a given slope, surface condition, or rainfall rate, with hydraulic roughness greater at steeper slopes and lower intensities. This study supports the hypothesis of slope-velocity equilibrium, implying that use of hydraulic equations, such as Chezy and Manning, in hillslope-scale runoff models is problematic because the coefficients vary with both slope and rainfall intensity.

  5. Evolution of star-bearing molecular clouds: the high-velocity HCO+ flow in NGC 2071

    International Nuclear Information System (INIS)

    Wootten, A.; Loren, R.B.; Sandqvist, A.; Friberg, P.; Hjalmarson, Aa.

    1984-01-01

    The J = 1-0 and J = 302 lines of HCO + and H 13 CO + have been observed in the molecular cloud NGC 2071, where they map the dense portions of a bidirectional molecular flow. The high resolution (42'') of our observations has enabled us to determine the distribution of mass, momentum , and energy in the flow as a function of projected distance from the cluster. Both momentum and energy diminish with distance from the central cluster of infrared sources. The highest velocities at a given intensity in this dense flow occur in a limited region coincident with an infrared cluster and the densest part of the molecular cloud. Higher resolution (33'') CO and 13 CO observations reveal that the extreme velocities in the flow occur in regions displaced on opposite sides of the cluster, suggesting that the flow only becomes visible in molecular line emission at distances approx.0.1 pc from its supposed source. Lower velocity material containing most of the mass of the flow is found over larger regions, as expected if the flow has decelerated as it has evolved. Assuming conservation of momentum, the historical rate of momentum injection is found to have been roughly constant over a period of 10 4 years, suggesting a constancy of the average luminosity of the central cluster over that time. The J = 3--2 HCO + profile does not show the absorption which is a prominent feature of the J = 1--0 profile, and the J = 3--2 line appears to be a useful probe of conditions specific to the dense cores of clouds. The high velocity HCO + emission correlates very well with spatial and velocity events of molecular hydrogen emission. The abundance of HCO + [X(HCO + )approx.10 -8 ], and by inference the electron density, is similar in material at all velocities

  6. Strength evolution of simulated carbonate-bearing faults: The role of normal stress and slip velocity

    Science.gov (United States)

    Mercuri, Marco; Scuderi, Marco Maria; Tesei, Telemaco; Carminati, Eugenio; Collettini, Cristiano

    2018-04-01

    A great number of earthquakes occur within thick carbonate sequences in the shallow crust. At the same time, carbonate fault rocks exhumed from a depth plasticity). We performed friction experiments on water-saturated simulated carbonate-bearing faults for a wide range of normal stresses (from 5 to 120 MPa) and slip velocities (from 0.3 to 100 μm/s). At high normal stresses (σn > 20 MPa) fault gouges undergo strain-weakening, that is more pronounced at slow slip velocities, and causes a significant reduction of frictional strength, from μ = 0.7 to μ = 0.47. Microstructural analysis show that fault gouge weakening is driven by deformation accommodated by cataclasis and pressure-insensitive deformation processes (pressure solution and granular plasticity) that become more efficient at slow slip velocity. The reduction in frictional strength caused by strain weakening behaviour promoted by the activation of pressure-insensitive deformation might play a significant role in carbonate-bearing faults mechanics.

  7. Evolution of microstructure and elastic wave velocities in dehydrated gypsum samples

    Science.gov (United States)

    Milsch, Harald; Priegnitz, Mike

    2012-12-01

    We report on changes in P and S-wave velocities and rock microstructure induced by devolatilization reactions using gypsum as a reference analog material. Cylindrical samples of natural alabaster were dehydrated in air, at ambient pressure, and temperatures between 378 and 423 K. Dehydration did not proceed homogeneously but via a reaction front moving sample inwards separating an outer highly porous rim from the remaining gypsum which, above approximately 393 (±5) K, concurrently decomposed into hemihydrate. Overall porosity was observed to continuously increase with reaction progress from approximately 2% for fully hydrated samples to 30% for completely dehydrated ones. Concurrently, P and S-wave velocities linearly decreased with porosity from 5.2 and 2.7 km/s to 1.0 and 0.7 km/s, respectively. It is concluded that a linearized empirical Raymer-type model extended by a critical porosity term and based on the respective time dependent mineral and pore volumes reasonably replicates the P and S-wave data in relation to reaction progress and porosity.

  8. Crustal evolution derived from the Izu-Bonin-Mariana arc velocity images

    Science.gov (United States)

    Takahashi, N.; Kodaira, S.; Tatsumi, Y.; Miura, S.; Sato, T.; Yamashita, M.; No, T.; Takahashi, T.; Noguchi, N.; Takizawa, K.; Kaiho, Y.; Kaneda, Y.

    2010-12-01

    The Izu-Bonin-Mariana arc is known as one of typical oceanic island arcs, which has developed by subduction between oceanic crusts producing continental materials. Japan Agency for Marine-Earth Science and Technology has carried out seismic surveys using a multi-channel reflection survey system (MCS) and ocean bottom seismographs (OBSs) in the Izu-Bonin-Mariana (IBM) arc since 2002, and reported these crustal images. As the results, we identified the structural characteristics of whole Izu-Bonin-Mariana arc. Rough structural characteristics are, 1) middle crust with Vp of 6 km/s, 2) upper part of the lower crust with Vp of 6.5-6.8 km/s, 3) lower part of the lower crust with Vp of 6.8-7.5 km/s, and 4) lower mantle velocity beneath the arc crusts. In addition, structural variation along the volcanic front, for example, thickness variation of andesitic layers was imaged and the distributions is consistent with those of rhyolite volcanoes, that is, it suggested that the cause the structural variation is various degree of crustal growth (Kodaira et al., 2007). Moreover, crustal thinning with high velocity lower crust across arc was also imaged, and it is interpreted that such crust has been influenced backarc opening (Takahashi et al., 2009). According to Tatsumi et al. (2008), andesitic middle crust is produced by differentiation of basaltic lower crust and a part of the restites are transformed to the upper mantle. This means that region showing much crustal differentiation has large volume of transformation of dense crustal materials to the mantle. We calculated volume profiles of the lower crust along all seismic lines based on the petrologic model, and compared them with observed real volumes obtained by seismic images. If the real volume of the lower crust is large, it means that the underplating of dense materials to the crustal bottom is dominant rather than transformation of dense materials to the upper mantle. According to obtained profiles to judge if the

  9. Temporal evolution of confined fast-ion velocity distributions measured by collective Thomson scattering in TEXTOR

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Bindslev, Henrik; Porte, L.

    2008-01-01

    reported [Bindslev , Phys. Rev. Lett. 97, 205005 2006]. Here we extend the discussion of these results which were obtained at the TEXTOR tokamak. The fast ions are generated by neutral-beam injection and ion-cyclotron resonance heating. The CTS system uses 100-150 kW of 110-GHz gyrotron probing radiation......Fast ions created in the fusion processes will provide up to 70% of the heating in ITER. To optimize heating and current drive in magnetically confined plasmas insight into fast-ion dynamics is important. First measurements of such dynamics by collective Thomson scattering (CTS) were recently...... of the velocity distribution after turnoff of the ion heating. These results are in close agreement with numerical simulations....

  10. THE APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT: FIRST DETECTION OF HIGH-VELOCITY MILKY WAY BAR STARS

    Energy Technology Data Exchange (ETDEWEB)

    Nidever, David L.; Zasowski, Gail; Majewski, Steven R.; Beaton, Rachael L.; Wilson, John C.; Skrutskie, Michael F.; O' Connell, Robert W. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Bird, Jonathan; Schoenrich, Ralph; Johnson, Jennifer A.; Sellgren, Kris [Department of Astronomy and the Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210 (United States); Robin, Annie C.; Schultheis, Mathias [Institut Utinam, CNRS UMR 6213, OSU THETA, Universite de Franche-Comte, 41bis avenue de l' Observatoire, F-25000 Besancon (France); Martinez-Valpuesta, Inma; Gerhard, Ortwin [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Shetrone, Matthew [McDonald Observatory, University of Texas at Austin, Fort Davis, TX 79734 (United States); Schiavon, Ricardo P. [Gemini Observatory, 670 North A' Ohoku Place, Hilo, HI 96720 (United States); Weiner, Benjamin [Steward Observatory, 933 North Cherry Street, University of Arizona, Tucson, AZ 85721 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Allende Prieto, Carlos, E-mail: dln5q@virginia.edu [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain); and others

    2012-08-20

    Commissioning observations with the Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, have produced radial velocities (RVs) for {approx}4700 K/M-giant stars in the Milky Way (MW) bulge. These high-resolution (R {approx} 22, 500), high-S/N (>100 per resolution element), near-infrared (NIR; 1.51-1.70 {mu}m) spectra provide accurate RVs ({epsilon}{sub V} {approx} 0.2 km s{sup -1}) for the sample of stars in 18 Galactic bulge fields spanning -1 Degree-Sign -32 Degree-Sign . This represents the largest NIR high-resolution spectroscopic sample of giant stars ever assembled in this region of the Galaxy. A cold ({sigma}{sub V} {approx} 30 km s{sup -1}), high-velocity peak (V{sub GSR} Almost-Equal-To +200 km s{sup -1}) is found to comprise a significant fraction ({approx}10%) of stars in many of these fields. These high RVs have not been detected in previous MW surveys and are not expected for a simple, circularly rotating disk. Preliminary distance estimates rule out an origin from the background Sagittarius tidal stream or a new stream in the MW disk. Comparison to various Galactic models suggests that these high RVs are best explained by stars in orbits of the Galactic bar potential, although some observational features remain unexplained.

  11. Evolution of scalar and velocity dynamics in planar shock-turbulence interaction

    Science.gov (United States)

    Boukharfane, R.; Bouali, Z.; Mura, A.

    2018-01-01

    Due to the short residence time of air in supersonic combustors, achieving efficient mixing in compressible turbulent reactive flows is crucial for the design of supersonic ramjet (Scramjet) engines. In this respect, improving the understanding of shock-scalar mixing interactions is of fundamental importance for such supersonic combustion applications. In these compressible flows, the interaction between the turbulence and the shock wave is reciprocal, and the coupling between them is very strong. A basic understanding of the physics of such complex interactions has already been obtained through the analysis of relevant simplified flow configurations, including propagation of the shock wave in density-stratified media, shock-wave-mixing-layer interaction, and shock-wave-vortex interaction. Amplification of velocity fluctuations and substantial changes in turbulence characteristic length scales are the most well-known outcomes of shock-turbulence interaction, which may also deeply influence scalar mixing between fuel and oxidizer. The effects of the shock wave on the turbulence have been widely characterized through the use of so-called amplification factors, and similar quantities are introduced herein to characterize the influence of the shock wave on scalar mixing. One of the primary goals of the present study is indeed to extend previous analyses to the case of shock-scalar mixing interaction, which is directly relevant to supersonic combustion applications. It is expected that the shock wave will affect the scalar dissipation rate (SDR) dynamics. Special emphasis is placed on the modification of the so-called turbulence-scalar interaction as a leading-order contribution to the production of mean SDR, i.e., a quantity that defines the mixing rate and efficiency. To the best of the authors' knowledge, this issue has never been addressed in detail in the literature, and the objective of the present study is to scrutinize this influence. The turbulent mixing of a

  12. Enveloping Aerodynamic Decelerator

    Science.gov (United States)

    Nock, Kerry T. (Inventor); Aaron, Kim M. (Inventor); McRonald, Angus D. (Inventor); Gates, Kristin L. (Inventor)

    2018-01-01

    An inflatable aerodynamic deceleration method and system is provided for use with an atmospheric entry payload. The inflatable aerodynamic decelerator includes an inflatable envelope and an inflatant, wherein the inflatant is configured to fill the inflatable envelope to an inflated state such that the inflatable envelope surrounds the atmospheric entry payload, causing aerodynamic forces to decelerate the atmospheric entry payload.

  13. EVOLUTION OF QUIESCENT AND STAR-FORMING GALAXIES SINCE z ∼ 1.5 AS A FUNCTION OF THEIR VELOCITY DISPERSIONS

    International Nuclear Information System (INIS)

    Bezanson, Rachel; Van Dokkum, Pieter; Franx, Marijn

    2012-01-01

    We measure stellar masses and structural parameters for 5500 quiescent and 20,000 star-forming galaxies at 0.3 < z ≤ 1.5 in the Newfirm Medium Band Survey COSMOS and UKIDSS UDS fields. We combine these measurements to infer velocity dispersions and determine how the number density of galaxies at fixed inferred dispersion, or the velocity dispersion function (VDF), evolves with time for each population. We show that the number of galaxies with high velocity dispersions appears to be surprisingly stable with time, regardless of their star formation history. Furthermore, the overall VDF for star-forming galaxies is constant with redshift, extending down to the lowest velocity dispersions probed by this study. The only galaxy population showing strong evolution are quiescent galaxies with low inferred dispersions, whose number density increases by a factor of ∼4 since z = 1.5. This buildup leads to an evolution in the quiescent fraction of galaxies such that the threshold dispersion above which quiescent galaxies dominate the counts moves to lower velocity dispersion with time. We show that our results are qualitatively consistent with a simple model in which star-forming galaxies quench and are added to the quiescent population. In order to compensate for the migration into the quiescent population, the velocity dispersions of star-forming galaxies must increase, with a rate that increases with dispersion.

  14. Effect of emplaced nZVI mass and groundwater velocity on PCE dechlorination and hydrogen evolution in water-saturated sand

    International Nuclear Information System (INIS)

    Kim, Hye-Jin; Leitch, Megan; Naknakorn, Bhanuphong; Tilton, Robert D.; Lowry, Gregory V.

    2017-01-01

    Highlights: • Reactivity of nZVI increased linearly with nZVI concentration above 10 g/L, but was non-linear below 10 g/L. • nZVI reactivity with PCE is more sensitive to solution redox potential than solution pH. • Mass transfer limits the reactivity of emplaced nZVI under typical groundwater flow velocity. • Lowering pH increases H_2 evolution from nZVI more than reactivity with PCE. • Design of nZVI remediation strategies should consider mass loading and flow velocity on performance and lifetime. - Abstract: The effect of nZVI mass loading and groundwater velocity on the tetrachloroethylene (PCE) dechlorination rate and the hydrogen evolution rate for poly(maleic acid-co-olefin) (MW = 12 K) coated nZVI was examined. In batch reactors, the PCE reaction rate constant (3.7 × 10"−"4 L hr"−"1 m"−"2) and hydrogen evolution rate constant (1.4 nanomol L hr"−"1 m"−"2) were independent of nZVI concentration above 10 g/L, but the PCE dechlorination rate decreased and the hydrogen evolution rate increased for nZVI concentration below 10 g/L. The nonlinearity between nZVI mass loading and PCE dechlorination and H_2 evolution was explained by differences in pH and E_h at each nZVI mass loading; PCE reactivity increased when solution E_h decreased, and the H_2 evolution rate increased with decreasing pH. Thus, nZVI mass loading of <5 g/L yields lower reactivity with PCE and lower efficiency of Fe° utilization than for higher nZVI mass loading. The PCE dechlorination rate increased with increasing pore-water velocity, suggesting that mass transfer limits the reaction at low porewater velocity. Overall, this work suggests that design of nZVI-based reactive barriers for groundwater treatment should consider the non-linear effects of both mass loading and flow velocity on performance and expected reactive lifetime.

  15. Effect of emplaced nZVI mass and groundwater velocity on PCE dechlorination and hydrogen evolution in water-saturated sand

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hye-Jin [Civil & Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15213-3890 (United States); Chemical Research Division, Environmental Health Research Department, National Institute of Environmental Research, Incheon 404-708 (Korea, Republic of); Leitch, Megan [Civil & Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15213-3890 (United States); Center for Environmental Implications of Nanotechnology, Carnegie Mellon University, Pittsburgh, PA 15213-3890 (United States); Naknakorn, Bhanuphong [Civil & Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15213-3890 (United States); Tilton, Robert D. [Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213-3890 (United States); Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213-3890 (United States); Center for Environmental Implications of Nanotechnology, Carnegie Mellon University, Pittsburgh, PA 15213-3890 (United States); Lowry, Gregory V., E-mail: glowry@cmu.edu [Civil & Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15213-3890 (United States); Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213-3890 (United States); Center for Environmental Implications of Nanotechnology, Carnegie Mellon University, Pittsburgh, PA 15213-3890 (United States)

    2017-01-15

    Highlights: • Reactivity of nZVI increased linearly with nZVI concentration above 10 g/L, but was non-linear below 10 g/L. • nZVI reactivity with PCE is more sensitive to solution redox potential than solution pH. • Mass transfer limits the reactivity of emplaced nZVI under typical groundwater flow velocity. • Lowering pH increases H{sub 2} evolution from nZVI more than reactivity with PCE. • Design of nZVI remediation strategies should consider mass loading and flow velocity on performance and lifetime. - Abstract: The effect of nZVI mass loading and groundwater velocity on the tetrachloroethylene (PCE) dechlorination rate and the hydrogen evolution rate for poly(maleic acid-co-olefin) (MW = 12 K) coated nZVI was examined. In batch reactors, the PCE reaction rate constant (3.7 × 10{sup −4} L hr{sup −1} m{sup −2}) and hydrogen evolution rate constant (1.4 nanomol L hr{sup −1} m{sup −2}) were independent of nZVI concentration above 10 g/L, but the PCE dechlorination rate decreased and the hydrogen evolution rate increased for nZVI concentration below 10 g/L. The nonlinearity between nZVI mass loading and PCE dechlorination and H{sub 2} evolution was explained by differences in pH and E{sub h} at each nZVI mass loading; PCE reactivity increased when solution E{sub h} decreased, and the H{sub 2} evolution rate increased with decreasing pH. Thus, nZVI mass loading of <5 g/L yields lower reactivity with PCE and lower efficiency of Fe° utilization than for higher nZVI mass loading. The PCE dechlorination rate increased with increasing pore-water velocity, suggesting that mass transfer limits the reaction at low porewater velocity. Overall, this work suggests that design of nZVI-based reactive barriers for groundwater treatment should consider the non-linear effects of both mass loading and flow velocity on performance and expected reactive lifetime.

  16. Storage envelopes or sleeves

    International Nuclear Information System (INIS)

    Freshwater, J.R.; Wagman, P.I.

    1980-01-01

    A storage envelope or sleeve particularly for processed X-ray films is described. It consists of front and back panels joined together at a hinge line and connected along the intermediate sides by connecting flaps. An inner pocket is formed from a third flap which is folded to lie against the inner face of the back panel. The panels may have additional score lines parallel to the closed sides of the envelope and the inner pocket so that the envelope and the inner pocket can accommodate bulky contents. The free edge of the pocket is inset from the open side of the envelope, and finger cut-outs may be provided to facilitate access to the contents of the envelope and the pocket. (author)

  17. Dispersion - does it degrade a pulse envelope

    International Nuclear Information System (INIS)

    Deighton, M.O.

    1985-01-01

    In hostile environments, transmitting information as ultrasonic Lamb wave pulses has advantages, since the stainless steel strip serving as a waveguide is very durable. Besides attenuation, velocity dispersion (inherent in Lamb waves) can be important even in fairly short guides. Theory shows that unlimited propagation of a pulsed r.f. envelope is possible, even with dispersion present. The constant group velocity needed would favour asub(o)-mode pulses over other modes, provided ordinary attenuation is small. An approximate formula indicates the useful range of a pulse, when group velocity does vary. (author)

  18. Radio Imaging of Envelopes of Evolved Stars

    Science.gov (United States)

    Cotton, Bill

    2018-04-01

    This talk will cover imaging of stellar envelopes using radio VLBI techniques; special attention will be paid to the technical differences between radio and optical/IR interferomery. Radio heterodyne receivers allow a straightforward way to derive spectral cubes and full polarization observations. Milliarcsecond resolution of very bright, i.e. non thermal, emission of molecular masers in the envelopes of evolved stars can be achieved using VLBI techniques with baselines of thousands of km. Emission from SiO, H2O and OH masers are commonly seen at increasing distance from the photosphere. The very narrow maser lines allow accurate measurements of the velocity field within the emitting region.

  19. Protective plasma envelope

    International Nuclear Information System (INIS)

    Bocharov, V.N.; Konstantinov, S.G.; Kudryavtsev, A.M.; Myskin, O.K.; Panasyuk, V.M.; Tsel'nik, F.A.

    1984-06-01

    A method of creating an annular plasma envelope used to protect the hot plasma from flows of impurities and gases from the walls of the vacuum chamber is described. The diameter of the envelope is 30 cm, the thickness of the wall is 1.5 cm, the length is 2.5 m, and its density is from 10 13 to 10 14 cm -3 . The envelope attenuates the incident (from outside) flow of helium 10-fold and the low of hydrogen 20-fold

  20. Safe operating envelope

    Energy Technology Data Exchange (ETDEWEB)

    Oliva, N [Ontario Hydro, Toronto, ON (Canada)

    1997-12-01

    Safe Operating Envelope is described representing: The outer bound of plant conditions within which day-to-day plant operation must be maintained in order to comply with regulatory requirements, associated safety design criteria and corporate nuclear safety goals. Figs.

  1. Safe operating envelope

    International Nuclear Information System (INIS)

    Oliva, N.

    1997-01-01

    Safe Operating Envelope is described representing: The outer bound of plant conditions within which day-to-day plant operation must be maintained in order to comply with regulatory requirements, associated safety design criteria and corporate nuclear safety goals. Figs

  2. Sequence evolution of the hypervariable region in the putative envelope region E2/NS1 of hepatitis C virus is correlated with specific humoral immune responses.

    OpenAIRE

    van Doorn, L J; Capriles, I; Maertens, G; DeLeys, R; Murray, K; Kos, T; Schellekens, H; Quint, W

    1995-01-01

    Sequence evolution of the hypervariable region 1 (HVR1) in the N terminus of E2/NS1 of hepatitis C virus (HCV) was studied retrospectively in six chimpanzees inoculated with the same genotype 1b strain, containing a unique predominant HVR1 sequence. Immediately after inoculation, all animals contained the same HVR predominant sequence. Two animals developed an acute self-limiting infection. Anti-HVR1 immunoglobulin G (IgG) was produced 40 to 60 days after inoculation and rapidly disappeared a...

  3. Dissipative Nonlinear Schrödinger Equation for Envelope Solitary Rossby Waves with Dissipation Effect in Stratified Fluids and Its Solution

    Directory of Open Access Journals (Sweden)

    Yunlong Shi

    2014-01-01

    Full Text Available We solve the so-called dissipative nonlinear Schrödinger equation by means of multiple scales analysis and perturbation method to describe envelope solitary Rossby waves with dissipation effect in stratified fluids. By analyzing the evolution of amplitude of envelope solitary Rossby waves, it is found that the shear of basic flow, Brunt-Vaisala frequency, and β effect are important factors to form the envelope solitary Rossby waves. By employing trial function method, the asymptotic solution of dissipative nonlinear Schrödinger equation is derived. Based on the solution, the effect of dissipation on the evolution of envelope solitary Rossby wave is also discussed. The results show that the dissipation causes a slow decrease of amplitude of envelope solitary Rossby waves and a slow increase of width, while it has no effect on the propagation velocity. That is quite different from the KdV-type solitary waves. It is notable that dissipation has certain influence on the carrier frequency.

  4. THE EVOLUTION OF GAS CLOUDS FALLING IN THE MAGNETIZED GALACTIC HALO: HIGH-VELOCITY CLOUDS (HVCs) ORIGINATED IN THE GALACTIC FOUNTAIN

    International Nuclear Information System (INIS)

    Kwak, Kyujin; Shelton, Robin L.; Raley, Elizabeth A.

    2009-01-01

    In the Galactic fountain scenario, supernovae and/or stellar winds propel material into the Galactic halo. As the material cools, it condenses into clouds. By using FLASH three-dimensional magnetohydrodynamic simulations, we model and study the dynamical evolution of these gas clouds after they form and begin to fall toward the Galactic plane. In our simulations, we assume that the gas clouds form at a height of z = 5 kpc above the Galactic midplane, then begin to fall from rest. We investigate how the cloud's evolution, dynamics, and interaction with the interstellar medium (ISM) are affected by the initial mass of the cloud. We find that clouds with sufficiently large initial densities (n ≥ 0.1 H atoms cm -3 ) accelerate sufficiently and maintain sufficiently large column densities as to be observed and identified as high-velocity clouds (HVCs) even if the ISM is weakly magnetized (1.3 μG). However, the ISM can provide noticeable resistance to the motion of a low-density cloud (n ≤ 0.01 H atoms cm -3 ) thus making it more probable that a low-density cloud will attain the speed of an intermediate-velocity cloud rather than the speed of an HVC. We also investigate the effects of various possible magnetic field configurations. As expected, the ISM's resistance is greatest when the magnetic field is strong and perpendicular to the motion of the cloud. The trajectory of the cloud is guided by the magnetic field lines in cases where the magnetic field is oriented diagonal to the Galactic plane. The model cloud simulations show that the interactions between the cloud and the ISM can be understood via analogy to the shock tube problem which involves shock and rarefaction waves. We also discuss accelerated ambient gas, streamers of material ablated from the clouds, and the cloud's evolution from a sphere-shaped to a disk- or cigar-shaped object.

  5. The limited role of recombination energy in common envelope removal

    Science.gov (United States)

    Grichener, Aldana; Sabach, Efrat; Soker, Noam

    2018-05-01

    We calculate the outward energy transport time by convection and photon diffusion in an inflated common envelope and find this time to be shorter than the envelope expansion time. We conclude therefore that most of the hydrogen recombination energy ends in radiation rather than in kinetic energy of the outflowing envelope. We use the stellar evolution code MESA and inject energy inside the envelope of an asymptotic giant branch star to mimic energy deposition by a spiraling-in stellar companion. During 1.7 years the envelope expands by a factor of more than 2. Along the entire evolution the convection can carry the energy very efficiently outwards, to the radius where radiative transfer becomes more efficient. The total energy transport time stays within several months, shorter than the dynamical time of the envelope. Had we included rapid mass loss, as is expected in the common envelope evolution, the energy transport time would have been even shorter. It seems that calculations that assume that most of the recombination energy ends in the outflowing gas might be inaccurate.

  6. Seismic Velocity Variation and Evolution of the Upper Oceanic Crust across the Mid-Atlantic Ridge at 1.3°S

    Science.gov (United States)

    Jian, H.; Singh, S. C.

    2017-12-01

    The oceanic crust that covers >70% of the solid earth is formed at mid-ocean ridges, but get modified as it ages. Understanding the evolution of oceanic crust requires investigations of crustal structures that extend from zero-age on the ridge axis to old crust. In this study, we analyze a part of a 2000-km-long seismic transect that crosses the Mid-Atlantic Ridge segment at 1.3°S, south of the Chain transform fault. The seismic data were acquired using a 12-km-long multi-sensor streamer and dense air-gun shots. Using a combination of downward continuation and seismic tomography methods, we have derived a high-resolution upper crustal velocity structure down to 2-2.5 km depth below the seafloor, from the ridge axis to 3.5 Ma on both sides of the ridge axis. The results demonstrate that velocities increase at all depths in the upper crust as the crust ages, suggesting that hydrothermal precipitations seal the upper crustal pore spaces. This effect is most significant in layer 2A, causing a velocity increase of 0.5-1 km/s after 1-1.5 Ma, beyond which the velocity increase is very small. Furthermore, the results exhibit a significant decrease in both the frequency and amplitude of the low-velocity anomalies associated with faults beyond 1-1.5 Ma, when faults become inactive, suggesting a linkage between the sealing of fault space and the extinction of hydrothermal activity. Besides, the off-axis velocities are systematically higher on the eastern side of the ridge axis compared to on the western side, suggesting that a higher hydrothermal activity should exist on the outside-corner ridge flank than on the inside-corner flank. While the tomography results shown here cover 0-3.5 Ma crust, the ongoing research will further extend the study area to older crust and also incorporating pre-stack migration and full waveform inversion methods to improve the seismic structure.

  7. HIV-1 envelope glycoprotein

    Science.gov (United States)

    Caulfield, Michael; Cupo, Albert; Dean, Hansi; Hoffenberg, Simon; King, C. Richter; Klasse, P. J.; Marozsan, Andre; Moore, John P.; Sanders, Rogier W.; Ward, Andrew; Wilson, Ian; Julien, Jean-Philippe

    2017-08-22

    The present application relates to novel HIV-1 envelope glycoproteins, which may be utilized as HIV-1 vaccine immunogens, and antigens for crystallization, electron microscopy and other biophysical, biochemical and immunological studies for the identification of broad neutralizing antibodies. The present invention encompasses the preparation and purification of immunogenic compositions, which are formulated into the vaccines of the present invention.

  8. PRESENT-DAY GALACTIC EVOLUTION: LOW-METALLICITY, WARM, IONIZED GAS INFLOW ASSOCIATED WITH HIGH-VELOCITY CLOUD COMPLEX A

    Energy Technology Data Exchange (ETDEWEB)

    Barger, K. A.; Haffner, L. M.; Wakker, B. P.; Hill, Alex S. [Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States); Madsen, G. J. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Duncan, A. K., E-mail: kbarger@astro.wisc.edu, E-mail: haffner@astro.wisc.edu, E-mail: Alex.Hill@csiro.au, E-mail: wakker@astro.wisc.edu, E-mail: greg.madsen@sydney.edu.au [Rose-Hulman Institute of Technology, Terre Haute, IN 47803 (United States)

    2012-12-20

    The high-velocity cloud Complex A is a probe of the physical conditions in the Galactic halo. The kinematics, morphology, distance, and metallicity of Complex A indicate that it represents new material that is accreting onto the Galaxy. We present Wisconsin H{alpha} Mapper kinematically resolved observations of Complex A over the velocity range of -250 to -50 km s{sup -1} in the local standard of rest reference frame. These observations include the first full H{alpha} intensity map of Complex A across (l, b) = (124 Degree-Sign , 18 Degree-Sign ) to (171 Degree-Sign , 53 Degree-Sign ) and deep targeted observations in H{alpha}, [S II] {lambda}6716, [N II] {lambda}6584, and [O I] {lambda}6300 toward regions with high H I column densities, background quasars, and stars. The H{alpha} data imply that the masses of neutral and ionized material in the cloud are similar, both being greater than 10{sup 6} M{sub Sun }. We find that the Bland-Hawthorn and Maloney model for the intensity of the ionizing radiation near the Milky Way is consistent with the known distance of the high-latitude part of Complex A and an assumed cloud geometry that puts the lower-latitude parts of the cloud at a distance of 7-8 kpc. This compatibility implies a 5% ionizing photon escape fraction from the Galactic disk. We also provide the nitrogen and sulfur upper abundance solutions for a series of temperatures, metallicities, and cloud configurations for purely photoionized gas; these solutions are consistent with the sub-solar abundances found by previous studies, especially for temperatures above 10{sup 4} K or for gas with a high fraction of singly ionized nitrogen and sulfur.

  9. Full waveform inversion using envelope-based global correlation norm

    Science.gov (United States)

    Oh, Ju-Won; Alkhalifah, Tariq

    2018-05-01

    To increase the feasibility of full waveform inversion on real data, we suggest a new objective function, which is defined as the global correlation of the envelopes of modelled and observed data. The envelope-based global correlation norm has the advantage of the envelope inversion that generates artificial low-frequency information, which provides the possibility to recover long-wavelength structure in an early stage. In addition, the envelope-based global correlation norm maintains the advantage of the global correlation norm, which reduces the sensitivity of the misfit to amplitude errors so that the performance of inversion on real data can be enhanced when the exact source wavelet is not available and more complex physics are ignored. Through the synthetic example for 2-D SEG/EAGE overthrust model with inaccurate source wavelet, we compare the performance of four different approaches, which are the least-squares waveform inversion, least-squares envelope inversion, global correlation norm and envelope-based global correlation norm. Finally, we apply the envelope-based global correlation norm on the 3-D Ocean Bottom Cable (OBC) data from the North Sea. The envelope-based global correlation norm captures the strong reflections from the high-velocity caprock and generates artificial low-frequency reflection energy that helps us recover long-wavelength structure of the model domain in the early stages. From this long-wavelength model, the conventional global correlation norm is sequentially applied to invert for higher-resolution features of the model.

  10. (Quasi-)Poisson enveloping algebras

    OpenAIRE

    Yang, Yan-Hong; Yao, Yuan; Ye, Yu

    2010-01-01

    We introduce the quasi-Poisson enveloping algebra and Poisson enveloping algebra for a non-commutative Poisson algebra. We prove that for a non-commutative Poisson algebra, the category of quasi-Poisson modules is equivalent to the category of left modules over its quasi-Poisson enveloping algebra, and the category of Poisson modules is equivalent to the category of left modules over its Poisson enveloping algebra.

  11. Atomistic simulation of tantalum nanoindentation: Effects of indenter diameter, penetration velocity, and interatomic potentials on defect mechanisms and evolution

    Energy Technology Data Exchange (ETDEWEB)

    Ruestes, C.J., E-mail: cjruestes@hotmail.com [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Facultad de Ciencias Exactas y Naturales, Univ. Nac. de Cuyo, Mendoza 5500 (Argentina); CONICET, Mendoza 5500 (Argentina); Stukowski, A. [Technische Universität Darmstadt, Darmstadt 64287 (Germany); Tang, Y. [Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072 (China); Tramontina, D.R. [Facultad de Ciencias Exactas y Naturales, Univ. Nac. de Cuyo, Mendoza 5500 (Argentina); Erhart, P. [Chalmers University of Technology, Department of Applied Physics, Gothenburg 41296 (Sweden); Remington, B.A. [Lawrence Livermore National Lab, Livermore, CA 94550 (United States); Urbassek, H.M. [Physics Department and Research Center OPTIMAS, University of Kaiserslautern, Kaiserslautern 67663 (Germany); Meyers, M.A. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Bringa, E.M. [Facultad de Ciencias Exactas y Naturales, Univ. Nac. de Cuyo, Mendoza 5500 (Argentina); CONICET, Mendoza 5500 (Argentina)

    2014-09-08

    Nanoindentation simulations are a helpful complement to experiments. There is a dearth of nanoindentation simulations for bcc metals, partly due to the lack of computationally efficient and reliable interatomic potentials at large strains. We carry out indentation simulations for bcc tantalum using three different interatomic potentials and present the defect mechanisms responsible for the creation and expansion of the plastic deformation zone: twins are initially formed, giving rise to shear loop expansion and the formation of sequential prismatic loops. The calculated elastic constants as function of pressure as well as stacking fault energy surfaces explain the significant differences found in the defect structures generated for the three potentials investigated in this study. The simulations enable the quantification of total dislocation length and twinning fraction. The indenter velocity is varied and, as expected, the penetration depth for the first pop-in (defect emission) event shows a strain rate sensitivity m in the range of 0.037–0.055. The effect of indenter diameter on the first pop-in is discussed. A new intrinsic length-scale model is presented based on the profile of the residual indentation and geometrically necessary dislocation theory.

  12. Atomistic simulation of tantalum nanoindentation: Effects of indenter diameter, penetration velocity, and interatomic potentials on defect mechanisms and evolution

    International Nuclear Information System (INIS)

    Ruestes, C.J.; Stukowski, A.; Tang, Y.; Tramontina, D.R.; Erhart, P.; Remington, B.A.; Urbassek, H.M.; Meyers, M.A.; Bringa, E.M.

    2014-01-01

    Nanoindentation simulations are a helpful complement to experiments. There is a dearth of nanoindentation simulations for bcc metals, partly due to the lack of computationally efficient and reliable interatomic potentials at large strains. We carry out indentation simulations for bcc tantalum using three different interatomic potentials and present the defect mechanisms responsible for the creation and expansion of the plastic deformation zone: twins are initially formed, giving rise to shear loop expansion and the formation of sequential prismatic loops. The calculated elastic constants as function of pressure as well as stacking fault energy surfaces explain the significant differences found in the defect structures generated for the three potentials investigated in this study. The simulations enable the quantification of total dislocation length and twinning fraction. The indenter velocity is varied and, as expected, the penetration depth for the first pop-in (defect emission) event shows a strain rate sensitivity m in the range of 0.037–0.055. The effect of indenter diameter on the first pop-in is discussed. A new intrinsic length-scale model is presented based on the profile of the residual indentation and geometrically necessary dislocation theory

  13. Rotational velocities of low-mass stars

    International Nuclear Information System (INIS)

    Stauffer, J.B.; Hartmann, L.W.; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA)

    1986-01-01

    The rotational velocities of stars provide important clues to how stars form and evolve. Yet until recently, studies of stellar rotation were limited to stars more massive than the sun. This is beginning to change, and an observational outline of the rotational velocity evolution of stars less massive than the sun can now be provided. Low-mass stars rotate slowly during the early stages of premain-sequence evolution, and spin up as they contract to the main sequence. This spin-up culminates in a brief period of very rapid rotation at an age of order 50 million years. Physical interpretation of this increase in rotation and the subsequent main-sequence spin-down are complicated by the possibility of differential internal rotation. The observed rapidity of spin-down among G dwarfs suggests that initially only the outer convective envelopes of these stars are slowed. The data suggest an intrinsic spread in angular momentum among young stars of the same mass and age, a spread which is apparently minimized by the angular-momentum loss mechanism in old low-mass stars. 83 references

  14. Thermal Activated Envelope

    DEFF Research Database (Denmark)

    Foged, Isak Worre; Pasold, Anke

    2015-01-01

    The research studies the making of a responsive architectural envelope based on bi-materials. The bi-materials are organized according to a method that combines different isotropic metals and plastic into an active composite structure that reacts to temperature variations. Through an evolutionary......, environmental dynamics and occupancy dynamics. Lastly, a physical prototype is created, which illustrates the physical expression of the bi-materials and the problems related to manufacturing of these composite structures.......The research studies the making of a responsive architectural envelope based on bi-materials. The bi-materials are organized according to a method that combines different isotropic metals and plastic into an active composite structure that reacts to temperature variations. Through an evolutionary...

  15. Uncertain data envelopment analysis

    CERN Document Server

    Wen, Meilin

    2014-01-01

    This book is intended to present the milestones in the progression of uncertain Data envelopment analysis (DEA). Chapter 1 gives some basic introduction to uncertain theories, including probability theory, credibility theory, uncertainty theory and chance theory. Chapter 2 presents a comprehensive review and discussion of basic DEA models. The stochastic DEA is introduced in Chapter 3, in which the inputs and outputs are assumed to be random variables. To obtain the probability distribution of a random variable, a lot of samples are needed to apply the statistics inference approach. Chapter 4

  16. The latest geodynamics in Asia: Synthesis of data on volcanic evolution, lithosphere motion, and mantle velocities in the Baikal-Mongolian region

    Directory of Open Access Journals (Sweden)

    Sergei Rasskazov

    2017-07-01

    Full Text Available From a synthesis of data on volcanic evolution, movement of the lithosphere, and mantle velocities in the Baikal-Mongolian region, we propose a comprehensive model for deep dynamics of Asia that assumes an important role of the Gobi, Baikal, and North Transbaikal transition-layer melting anomalies. This layer was distorted by lower-mantle fluxes at the beginning of the latest geodynamic stage (i.e. in the early late Cretaceous due to avalanches of slab material that were stagnated beneath the closed fragments of the Solonker, Ural-Mongolian paleoceans and Mongol-Okhotsk Gulf of Paleo-Pacific. At the latest geodynamic stage, Asia was involved in east–southeast movement, and the Pacific plate moved in the opposite direction with subduction under Asia. The weakened upper mantle region of the Gobi melting anomaly provided a counterflow connected with rollback in the Japan Sea area. These dynamics resulted in the formation of the Honshu-Korea flexure of the Pacific slab. A similar weakened upper mantle region of the North Transbaikal melting anomaly was associated with the formation of the Hokkaido-Amur flexure of the Pacific slab, formed due to progressive pull-down of the slab material into the transition layer in the direction of the Pacific plate and Asia convergence. The early–middle Miocene structural reorganization of the mantle processes in Asia resulted in the development of upper mantle low-velocity domains associated with the development of rifts and orogens. We propose that extension at the Baikal Rift was caused by deviator flowing mantle material, initiated under the moving lithosphere in the Baikal melting anomaly. Contraction at the Hangay orogen was created by facilitation of the tectonic stress transfer from the Indo-Asian interaction zone due to the low-viscosity mantle in the Gobi melting anomaly.

  17. The dynamics of short envelope solitons in media with controlled dispersion

    International Nuclear Information System (INIS)

    Aseeva, N.V.; Gromov, E.M.; Tyutin, V.V.

    2007-01-01

    The dynamics of short envelope solitons in media with controlled dispersion is investigated in the framework of the third-order nonlinear Schroedinger equation. Evolution of the solitons amplitude is analyzed in the adiabatic approximation. The existence of short envelope solitons independent from linear dispersion inhomogeneity is shown

  18. Refractive index dispersion measurement using carrier-envelope phasemeters

    International Nuclear Information System (INIS)

    Hansinger, Peter; Töpfer, Philipp; Adolph, Daniel; Hoff, Dominik; Rathje, Tim; Sayler, A Max; Paulus, Gerhard G; Dimitrov, Nikolay; Dreischuh, Alexander

    2017-01-01

    We introduce a novel method for direct and accurate measurement of refractive index dispersion based on carrier-envelope phase detection of few-cycle laser pulses, exploiting the difference between phase and group velocity in a dispersive medium. In a layout similar to an interferometer, two carrier-envelope phasemeters are capable of measuring the dispersion of a transparent or reflective sample, where one phasemeter serves as the reference and the other records the influence of the sample. Here we report on proof-of-principle measurements that already reach relative uncertainties of a few 10 −4 . Further development is expected to allow for unprecedented precision. (paper)

  19. Solitons, envelope solitons in collisonless plasmas

    International Nuclear Information System (INIS)

    Ichikawa, Y.H.; Watanabe, S.

    1977-08-01

    A review is given to extensive development of theoretical, computational and experimental studies of nonlinear wave propagation in collisionless plasmas. Firstly, the historical experiment of Ikezi et al. is discussed in comparison with theoretical analysis based on the Korteweg-de Vries equation. Systematic discrepancy between the observation and the theoretical prediction suggests that it is necessary to examine such as higher order mode coupling effect and contribution of trapped particles. Secondly, effects of the nonlinear Landau damping on the envelope solution of ion plasma wave is discussed on the basis of theoretical study of Ichikawa-Taniuti, experimental observation of Watanabe and numerical analysis of Yajima et al. Finally, a new type of evolution equation derived for the Alfven wave is examined in some detail. The rigorous solution obtained for this mode represents a new kind of envelope solution, in which both of its phase and amplitude are subject to modulation of comparable spatial extension. In conclusion, the emphasis will be placed on the fact that much more intensive experimental researches are expected to be done, since the powerful methods to disentangle various nonlinear evolution equations are now available for theoretical approach. (auth.)

  20. The LHC on an envelope

    CERN Multimedia

    2007-01-01

    The series of envelopes featuring CERN issued this summer was a huge success. The French postal services of the Pays de Gex will shortly be launching the second set of pre-paid envelopes issued in collaboration with the Laboratory this year, this time highlighting the LHC. Five thousand envelopes describing the accelerator’s capabilities will go on sale on 12 November, and some of the packs will even contain a small sample of the cables from the heart of the LHC magnets. The sets of ten pre-paid envelopes will tell you everything about CERN’s flagship accelerator, from its astounding technical capabilities to its spin-offs in the fields of technology and human resources. Each envelope will feature a different attribute or spin-off of the LHC. People will be invited to consult CERN’s public website for more detailed explanations if they want to know more. The new envelopes will be available from five post offices in the Pays ...

  1. The LHC in an envelope

    CERN Multimedia

    2007-01-01

    The series of envelopes featuring CERN issued this summer was a huge success. The French postal services of the Pays de Gex will shortly be launching the second set of pre-paid envelopes issued in collaboration with the Laboratory this year, this time highlighting the LHC. Five thousand envelopes describing the accelerator’s capabilities will go on sale on 12 November, and some of the packs will even contain a small sample of the cables from the heart of the LHC magnets. The sets of ten pre-paid envelopes will tell you everything about CERN’s flagship accelerator, from its astounding technical capabilities to its spin-offs in the fields of technology and human resources. Each envelope will feature a different attribute or spin-off of the LHC. People will be invited to consult CERN’s public website for more detailed explanations if they want to know more. The new envelopes will be available from five post offices in the Pays de Gex (Ferney-Voltaire, Prévessin...

  2. Evolution of massive close binary stars

    International Nuclear Information System (INIS)

    Masevich, A.G.; Tutukov, A.V.

    1982-01-01

    Some problems of the evolution of massive close binary stars are discussed. Most of them are nonevolutionized stars with close masses of components. After filling the Roche cavity and exchange of matter between the components the Wolf-Rayet star is formed. As a result of the supernovae explosion a neutron star or a black hole is formed in the system. The system does not disintegrate but obtains high space velocity owing to the loss of the supernovae envelope. The satellite of the neutron star or black hole - the star of the O or B spectral class loses about 10 -6 of the solar mass for a year. Around the neighbouring component a disc of this matter is formed the incidence of which on a compact star leads to X radiation appearance. The neutron star cannot absorb the whole matter of the widening component and the binary system submerges into the common envelope. As a result of the evolution of massive close binary systems single neutron stars can appear which after the lapse of some time become radiopulsars. Radiopulsars with such high space velocities have been found in our Galaxy [ru

  3. Decoupling of magnetic fields in collapsing protostellar envelopes and disc formation and fragmentation

    Science.gov (United States)

    Zhao, Bo; Caselli, Paola; Li, Zhi-Yun; Krasnopolsky, Ruben

    2018-02-01

    Efficient magnetic braking is a formidable obstacle to the formation of rotationally supported discs (RSDs) around protostars in magnetized dense cores. We have previously shown, through 2D (axisymmetric) non-ideal magnetohydrodynamic simulations, that removing very small grains (VSGs: ∼10 Å to few 100 Å) can greatly enhance ambipolar diffusion and enable the formation of RSDs. Here, we extend the simulations of disc formation enabled by VSG removal to 3D. We find that the key to this scenario of disc formation is that the drift velocity of the magnetic field almost cancels out the infall velocity of the neutrals in the 102-103 au scale 'pseudo-disc' where the field lines are most severely pinched and most of protostellar envelope mass infall occurs. As a result, the bulk neutral envelope matter can collapse without dragging much magnetic flux into the disc-forming region, which lowers the magnetic braking efficiency. We find that the initial discs enabled by VSG removal tend to be Toomre-unstable, which leads to the formation of prominent spiral structures that function as centrifugal barriers. The piling-up of infall material near the centrifugal barrier often produces dense fragments of tens of Jupiter masses, especially in cores that are not too strongly magnetized. Some fragments accrete on to the central stellar object, producing bursts in mass accretion rate. Others are longer lived, although whether they can survive for a long term to produce multiple systems remains to be ascertained. Our results highlight the importance of dust grain evolution in determining the formation and properties of protostellar discs and potentially multiple systems.

  4. Safeguards Envelope Progress FY08

    International Nuclear Information System (INIS)

    Bean, Robert; Metcalf, Richard; Bevill, Aaron

    2008-01-01

    The Safeguards Envelope Project met its milestones by creating a rudimentary safeguards envelope, proving the value of the approach on a small scale, and determining the most appropriate path forward. The Idaho Chemical Processing Plant's large cache of reprocessing process monitoring data, dubbed UBER Data, was recovered and used in the analysis. A probabilistic Z test was used on a Markov Monte Carlo simulation of expected diversion data when compared with normal operating data. The data regarding a fully transient event in a tank was used to create a simple requirement, representative of a safeguards envelope, whose impact was a decrease in operating efficiency by 1.3% but an increase in material balance period of 26%. This approach is operator, state, and international safeguards friendly and should be applied to future reprocessing plants. Future requirements include tank-to-tank correlations in reprocessing facilities, detailed operations impact studies, simulation inclusion, automated optimization, advanced statistics analysis, and multi-attribute utility analysis

  5. Moisture dynamics in building envelopes

    Energy Technology Data Exchange (ETDEWEB)

    Peuhkuri, R.

    2003-07-01

    The overall scope of this Thesis 'Moisture dynamics in building envelopes' has been to characterise how the various porous insulation materials investigated performed hygro thermally under conditions similar to those in a typical building envelope. As a result of the changing temperature and moisture conditions in the exterior weather and indoor climate the materials dynamically absorb and release moisture. The complexity of the impact of these conditions on the resulting moisture transport and content of the materials has been studied in this Thesis with controlled laboratory tests. (au)

  6. Moisture Dynamics in Building Envelopes

    DEFF Research Database (Denmark)

    Peuhkuri, Ruut Hannele

    2003-01-01

    The overall scope of this Thesis "Moisture dynamics in building envelopes" has been to characterise how the various porous insulation materials investigated performed hygrothermally under conditions similar to those in a typical building envelope. As a result of the changing temperature...... part of the Thesis consists of a theory and literature review on the moisture storage and transport processes (Chapter 2), on the non-Fickian moisture transport (Chapter 3)and on the methods for determining the moisture properties (Chapter 4). In the second part, the conducted experimental work...

  7. Pushing the Envelope of Extreme Space Weather

    Science.gov (United States)

    Pesnell, W. D.

    2014-12-01

    Extreme Space Weather events are large solar flares or geomagnetic storms, which can cost billions of dollars to recover from. We have few examples of such events; the Carrington Event (the solar superstorm) is one of the few that had superlatives in three categories: size of solar flare, drop in Dst, and amplitude of aa. Kepler observations show that stars similar to the Sun can have flares releasing millions of times more energy than an X-class flare. These flares and the accompanying coronal mass ejections could strongly affect the atmosphere surrounding a planet. What level of solar activity would be necessary to strongly affect the atmosphere of the Earth? Can we map out the envelope of space weather along the evolution of the Sun? What would space weather look like if the Sun stopped producing a magnetic field? To what extreme should Space Weather go? These are the extremes of Space Weather explored in this talk.

  8. Gravitational Waves from Accreting Neutron Stars Undergoing Common-envelope Inspiral

    Science.gov (United States)

    Holgado, A. Miguel; Ricker, Paul M.; Huerta, E. A.

    2018-04-01

    The common-envelope phase is a likely formation channel for close binary systems containing compact objects. Neutron stars in common envelopes accrete at a fraction of the Bondi–Hoyle–Lyttleton accretion rate, since the stellar envelope is inhomogeneous, but they may still be able to accrete at hypercritical rates (though not enough to become black holes). We show that common-envelope systems consisting of a neutron star with a massive primary may be gravitational-wave (GW) sources detectable in the Advanced LIGO band as far away as the Magellanic Clouds. To characterize their evolution, we perform orbital integrations using 1D models of 12 M ⊙ and 20 M ⊙ primaries, considering the effects of density gradient on the accretion onto the NS and spin evolution. From the range of possible accretion rates relevant to common-envelope evolution, we find that these systems may be louder GW sources than low-mass X-ray binaries like Sco X-1, which are currently the target of directed searches for continuous GWs. We also find that their strain amplitude signal may allow for novel constraints on the orbital separation and inspiral timescale in common envelopes when combined with pre-common-envelope electromagnetic observations.

  9. Supernova 2010as: the lowest-velocity member of a family of flat-velocity type IIb supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Folatelli, Gastón; Bersten, Melina C.; Nomoto, Ken' ichi [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Kuncarayakti, Hanindyo; Hamuy, Mario [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Olivares Estay, Felipe; Pignata, Giuliano [Departamento de Ciencias Fisicas, Universidad Andres Bello, Avda. Republica 252, Santiago (Chile); Anderson, Joseph P. [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago (Chile); Holmbo, Simon; Stritzinger, Maximilian [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Morrell, Nidia; Contreras, Carlos; Phillips, Mark M. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Förster, Francisco [Center for Mathematical Modelling, Universidad de Chile, Avenida Blanco Encalada 2120 Piso 7, Santiago (Chile); Prieto, José Luis [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Peyton Hall, Princeton, NJ 08544 (United States); Valenti, Stefano [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Afonso, Paulo; Altenmüller, Konrad; Elliott, Jonny, E-mail: gaston.folatelli@ipmu.jp [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße 1, D-85740 Garching (Germany); and others

    2014-09-01

    We present extensive optical and near-infrared photometric and spectroscopic observations of the stripped-envelope supernova SN 2010as. Spectroscopic peculiarities such as initially weak helium features and low expansion velocities with a nearly flat evolution place this object in the small family of events previously identified as transitional Type Ib/c supernovae (SNe). There is ubiquitous evidence of hydrogen, albeit weak, in this family of SNe, indicating that they are in fact a peculiar kind of Type IIb SNe that we name 'flat-velocity' Type IIb. The flat-velocity evolution—which occurs at different levels between 6000 and 8000 km s{sup –1} for different SNe—suggests the presence of a dense shell in the ejecta. Despite the spectroscopic similarities, these objects show surprisingly diverse luminosities. We discuss the possible physical or geometrical unification picture for such diversity. Using archival Hubble Space Telescope images, we associate SN 2010as with a massive cluster and derive a progenitor age of ≈6 Myr, assuming a single star-formation burst, which is compatible with a Wolf-Rayet progenitor. Our hydrodynamical modeling, on the contrary, indicates that the pre-explosion mass was relatively low, ≈4 M {sub ☉}. The seeming contradiction between a young age and low pre-SN mass may be solved by a massive interacting binary progenitor.

  10. Nature of 'unseen' galactic envelopes

    International Nuclear Information System (INIS)

    McCrea, W.H.

    1983-01-01

    In this paper, it is suggested that unseen matter in a galactic envelope or in a group of galaxies may consist of substellar bodies originating as the first permanent 'stars' in the formation of a very massive galaxy according to a model for galaxy-formation on the basis of simple big-bang cosmology. (Auth.)

  11. Handbook on data envelopment analysis

    CERN Document Server

    Cooper, William W; Zhu, Joe

    2011-01-01

    Focusing on extensively used Data Envelopment Analysis topics, this volume aims to both describe the state of the field and extend the frontier of DEA research. New chapters include DEA models for DMUs, network DEA, models for supply chain operations and applications, and new developments.

  12. SiO maser emission as a density tracer of circumstellar envelopes

    Science.gov (United States)

    Stroh, Michael; Pihlstrom, Ylva; Sjouwerman, Lorant

    2018-06-01

    The circumstellar envelopes (CSEs) of evolved stars offer a method to construct a sample of point-masses along the full Galactic plane, which can be used to test models of the gravitational potential. In the CSEs of red giants, SiO maser emission is frequently observed at 43 and 86 GHz, providing line-of-sight velocities. The Bulge Asymmetries and Dynamical Evolution (BAaDE) project aims to explore the complex structure of the inner Galaxy and Galactic Bulge, by observing 43 GHz SiO at the Very Large Array and 86 GHz SiO at the Atacama Large Millimeter/submillimeter Array, with an expected final sample of about 20,000 line-of-sight velocities and positions. We observed the 43 GHz and 86 GHz transitions near-simultaneously in a subsample of the sources using the Australia Telescope Compact Array and found that on average the 43 GHz v=1 line is 1.3 times stronger than the 86 GHz v=1 line. The presence of a detectable 43 GHz v=3 line alters the statistics, consistent with the SiO masers displaying 43 GHz v=3 emission arising in a denser regime in the circumstellar shell compared to those without. Comparing our results with radiative models implies that the 43 GHz v=3 line is a tracer of density variations caused by stellar pulsations. We will discuss these results in the context of the BAaDE project.

  13. Solitons of an envelope in an inhomogeneous medium

    International Nuclear Information System (INIS)

    Churilov, S.M.

    1982-01-01

    Solutions of the Schroedinger nonlinear equation (SNE) used for the description of evolution of a wave packet envelope has been investigated in inhomogeneous and nonstationary media. It is shown that the SNE solution possessing two important properties exists. Firstly, the wave packet remains localized when propagating in an inhomogeneous medium. Secondly, the soliton width and amplitude are determined only with local characteristics of medium and don't depend on the prehistory. Problem of limits of obtained result applicability has been considered

  14. Envelope matching for enhanced backward Raman amplification by using self-ionizing plasmas

    International Nuclear Information System (INIS)

    Zhang, Z. M.; Zhang, B.; Hong, W.; Teng, J.; He, S. K.; Gu, Y. Q.; Yu, M. Y.

    2014-01-01

    Backward Raman amplification (BRA) in plasmas has been promoted as a means for generating ultrapowerful laser pulses. For the purpose of achieving the maximum intensities over the shortest distances, an envelope matching between the seed pulse and the amplification gain is required, i.e., the seed pulse propagates at the same velocity with the gain such that the peak of the seed pulse can always enjoy the maximum gain. However, such an envelope matching is absent in traditional BRA because in the latter the amplification gain propagates at superluminous velocity while the seed pulse propagates at the group velocity, which is less than the speed of light. It is shown here that, by using self-ionizing plasmas, the speed of the amplification gain can be well reduced to reach the envelope matching regime. This results in a favorable BRA process, in which higher saturated intensity, shorter interaction length and higher energy-transfer efficiency are achieved

  15. Shear-Velocity Structure and Azimuthal and Radial Anisotropy Beneath the Kaapvaal Craton From Bayesian Inversion of Surface-Wave Data: Inferences for the Architecture and Early Evolution of Cratons

    Science.gov (United States)

    Lebedev, S.; Ravenna, M.; Adam, J.

    2017-12-01

    Seismic anisotropy provides essential information on the deformation of the lithosphere. Knowledge of anisotropy also allows us to isolate the isotropic-average seismic velocities, relatable to the lithospheric temperature and composition. We use Rayleigh and Love-wave phase velocities and their azimuthal anisotropy measured in broad period ranges across the footprint of the Southern Africa Seismic Experiment (SASE), from the Kaapvaal Craton to the Limpopo Belt. We invert the data using our recently developed, fully non-linear Markov Chain Monte Carlo method and determine, for the first time, both the isotropic-average S velocity and its radial and azimuthal anisotropy as a function of depth from the upper crust down to the asthenosphere. The probabilistic inversion provides a way to quantify non-uniqueness, using direct parameter-space sampling, and assess model uncertainties. The high-velocity anomaly indicative of the cold cratonic lithosphere bottoms at 200-250 km beneath the central and western Kaapvaal Craton, underlain by a low-velocity zone. Beneath northern Kaapvaal and Limpopo, by contrast, high velocities extend down to 300-350 km. Although this does not require a lithosphere that has maintained this thickness over a geologically long time, the data does require the mantle to be anomalously cold down to 300-350 km. Interestingly, topography correlates with the thickness of this high-velocity layer, with lower elevations where the lid is thicker. Radial shear-wave anisotropy is in the 2-5 percent range (Vsh > Vsv) from the lower crust down to 200 km, below which depth it decreases gradually. Radial variations in the amplitude of radial anisotropy show no clear relationship with those in the amplitude of azimuthal anisotropy or isotropic-average Vs anomalies. Azimuthal anisotropy changes the fast-propagation direction near the base of the lithosphere (200-300 km depth), from the laterally varying fast azimuths in the lower lithosphere to a spatially

  16. Conservation of the egg envelope digestion mechanism of hatching enzyme in euteleostean fishes.

    Science.gov (United States)

    Kawaguchi, Mari; Yasumasu, Shigeki; Shimizu, Akio; Sano, Kaori; Iuchi, Ichiro; Nishida, Mutsumi

    2010-12-01

    We purified two hatching enzymes, namely high choriolytic enzyme (HCE; EC 3.4.24.67) and low choriolytic enzyme (LCE; EC 3.4.24.66), from the hatching liquid of Fundulus heteroclitus, which were named Fundulus HCE (FHCE) and Fundulus LCE (FLCE). FHCE swelled the inner layer of egg envelope, and FLCE completely digested the FHCE-swollen envelope. In addition, we cloned three Fundulus cDNAs orthologous to cDNAs for the medaka precursors of egg envelope subunit proteins (i.e. choriogenins H, H minor and L) from the female liver. Cleavage sites of FHCE and FLCE on egg envelope subunit proteins were determined by comparing the N-terminal amino acid sequences of digests with the sequences deduced from the cDNAs for egg envelope subunit proteins. FHCE and FLCE cleaved different sites of the subunit proteins. FHCE efficiently cleaved the Pro-X-Y repeat regions into tripeptides to dodecapeptides to swell the envelope, whereas FLCE cleaved the inside of the zona pellucida domain, the core structure of egg envelope subunit protein, to completely digest the FHCE-swollen envelope. A comparison showed that the positions of hatching enzyme cleavage sites on egg envelope subunit proteins were strictly conserved between Fundulus and medaka. Finally, we extended such a comparison to three other euteleosts (i.e. three-spined stickleback, spotted halibut and rainbow trout) and found that the egg envelope digestion mechanism was well conserved among them. During evolution, the egg envelope digestion by HCE and LCE orthologs was established in the lineage of euteleosts, and the mechanism is suggested to be conserved. © 2010 The Authors Journal compilation © 2010 FEBS.

  17. Safeguards Envelope Progress FY08

    Energy Technology Data Exchange (ETDEWEB)

    Robert Bean; Richard Metcalf; Aaron Bevill

    2008-09-01

    The Safeguards Envelope Project met its milestones by creating a rudimentary safeguards envelope, proving the value of the approach on a small scale, and determining the most appropriate path forward. The Idaho Chemical Processing Plant’s large cache of reprocessing process monitoring data, dubbed UBER Data, was recovered and used in the analysis. A probabilistic Z test was used on a Markov Monte Carlo simulation of expected diversion data when compared with normal operating data. The data regarding a fully transient event in a tank was used to create a simple requirement, representative of a safeguards envelope, whose impact was a decrease in operating efficiency by 1.3% but an increase in material balance period of 26%. This approach is operator, state, and international safeguards friendly and should be applied to future reprocessing plants. Future requirements include tank-to-tank correlations in reprocessing facilities, detailed operations impact studies, simulation inclusion, automated optimization, advanced statistics analysis, and multi-attribute utility analysis.

  18. Transparent ceramic lamp envelope materials

    Energy Technology Data Exchange (ETDEWEB)

    Wei, G C [OSRAM SYLVANIA, 71 Cherry Hill Drive, Beverly, MA 01915 (United States)

    2005-09-07

    Transparent ceramic materials with optical qualities comparable to single crystals of similar compositions have been developed in recent years, as a result of the improved understanding of powder-processing-fabrication- sintering-property inter-relationships. These high-temperature materials with a range of thermal and mechanical properties are candidate envelopes for focused-beam, short-arc lamps containing various fills operating at temperatures higher than quartz. This paper reviews the composition, structure and properties of transparent ceramic lamp envelope materials including sapphire, small-grained polycrystalline alumina, aluminium oxynitride, yttrium aluminate garnet, magnesium aluminate spinel and yttria-lanthana. A satisfactory thermal shock resistance is required for the ceramic tube to withstand the rapid heating and cooling cycles encountered in lamps. Thermophysical properties, along with the geometry, size and thickness of a transparent ceramic tube, are important parameters in the assessment of its resistance to fracture arising from thermal stresses in lamps during service. The corrosive nature of lamp-fill liquid and vapour at high temperatures requires that all lamp components be carefully chosen to meet the target life. The wide range of new transparent ceramics represents flexibility in pushing the limit of envelope materials for improved beamer lamps.

  19. Simulating ice thickness and velocity evolution of Upernavik Isstrøm 1849-2012 by forcing prescribed terminus positions in ISSM

    Science.gov (United States)

    Haubner, Konstanze; Box, Jason E.; Schlegel, Nicole J.; Larour, Eric Y.; Morlighem, Mathieu; Solgaard, Anne M.; Kjeldsen, Kristian K.; Larsen, Signe H.; Rignot, Eric; Dupont, Todd K.; Kjær, Kurt H.

    2018-04-01

    Tidewater glacier velocity and mass balance are known to be highly responsive to terminus position change. Yet it remains challenging for ice flow models to reproduce observed ice margin changes. Here, using the Ice Sheet System Model (ISSM; Larour et al. 2012), we simulate the ice velocity and thickness changes of Upernavik Isstrøm (north-western Greenland) by prescribing a collection of 27 observed terminus positions spanning 164 years (1849-2012). The simulation shows increased ice velocity during the 1930s, the late 1970s and between 1995 and 2012 when terminus retreat was observed along with negative surface mass balance anomalies. Three distinct mass balance states are evident in the reconstruction: (1849-1932) with near zero mass balance, (1932-1992) with ice mass loss dominated by ice dynamical flow, and (1998-2012), when increased retreat and negative surface mass balance anomalies led to mass loss that was twice that of any earlier period. Over the multi-decadal simulation, mass loss was dominated by thinning and acceleration responsible for 70 % of the total mass loss induced by prescribed change in terminus position. The remaining 30 % of the total ice mass loss resulted directly from prescribed terminus retreat and decreasing surface mass balance. Although the method can not explain the cause of glacier retreat, it enables the reconstruction of ice flow and geometry during 1849-2012. Given annual or seasonal observed terminus front positions, this method could be a useful tool for evaluating simulations investigating the effect of calving laws.

  20. Cortical processing of dynamic sound envelope transitions.

    Science.gov (United States)

    Zhou, Yi; Wang, Xiaoqin

    2010-12-08

    Slow envelope fluctuations in the range of 2-20 Hz provide important segmental cues for processing communication sounds. For a successful segmentation, a neural processor must capture envelope features associated with the rise and fall of signal energy, a process that is often challenged by the interference of background noise. This study investigated the neural representations of slowly varying envelopes in quiet and in background noise in the primary auditory cortex (A1) of awake marmoset monkeys. We characterized envelope features based on the local average and rate of change of sound level in envelope waveforms and identified envelope features to which neurons were selective by reverse correlation. Our results showed that envelope feature selectivity of A1 neurons was correlated with the degree of nonmonotonicity in their static rate-level functions. Nonmonotonic neurons exhibited greater feature selectivity than monotonic neurons in quiet and in background noise. The diverse envelope feature selectivity decreased spike-timing correlation among A1 neurons in response to the same envelope waveforms. As a result, the variability, but not the average, of the ensemble responses of A1 neurons represented more faithfully the dynamic transitions in low-frequency sound envelopes both in quiet and in background noise.

  1. Safeguards Envelope Progress FY10

    International Nuclear Information System (INIS)

    Metcalf, Richard

    2010-01-01

    The Safeguards Envelope is a strategy to determine a set of specific operating parameters within which nuclear facilities may operate to maximize safeguards effectiveness without sacrificing safety or plant efficiency. This paper details the additions to the advanced operating techniques that will be applied to real plant process monitoring (PM) data from the Idaho Chemical Processing Plant (ICPP). Research this year focused on combining disparate pieces of data together to maximize operating time with minimal downtime due to safeguards. A Chi-Square and Croiser's cumulative sum were both included as part of the new analysis. Because of a major issue with the original data, the implementation of the two new tests did not add to the existing set of tests, though limited one-variable optimization made a small increase in detection probability. Additional analysis was performed to determine if prior analysis would have caused a major security or safety operating envelope issue. It was determined that a safety issue would have resulted from the prior research, but that the security may have been increased under certain conditions.

  2. Fullerenes and fulleranes in circumstellar envelopes

    International Nuclear Information System (INIS)

    Zhang, Yong; Kwok, Sun; Sadjadi, SeyedAbdolreza

    2016-01-01

    Three decades of search have recently led to convincing discoveries of cosmic fullerenes. The presence of C_6_0 and C"+ _6_0 in both circumstellar and interstellar environments suggests that these molecules and their derivatives can be efficiently formed in circumstellar envelopes and survive in harsh conditions. Detailed analysis of the infrared bands from fullerenes and their connections with the local properties can provide valuable information on the physical conditions and chemical processes that occurred in the late stages of stellar evolution. The identification of C"+ _6_0 as the carrier of four diffuse interstellar bands (DIBs) suggests that fullerene- related compounds are abundant in interstellar space and are essential for resolving the DIB mystery. Experiments have revealed a high hydrogenation rate when C_6_0 is exposed to atomic hydrogen, motivating the attempt to search for cosmic fulleranes. In this paper, we present a short review of current knowledge of cosmic fullerenes and fulleranes and briefly discuss the implications on circumstellar chemistry. (paper)

  3. Surface flux transport simulations: Effect of inflows toward active regions and random velocities on the evolution of the Sun's large-scale magnetic field

    Science.gov (United States)

    Martin-Belda, D.; Cameron, R. H.

    2016-02-01

    Aims: We aim to determine the effect of converging flows on the evolution of a bipolar magnetic region (BMR), and to investigate the role of these inflows in the generation of poloidal flux. We also discuss whether the flux dispersal due to turbulent flows can be described as a diffusion process. Methods: We developed a simple surface flux transport model based on point-like magnetic concentrations. We tracked the tilt angle, the magnetic flux and the axial dipole moment of a BMR in simulations with and without inflows and compared the results. To test the diffusion approximation, simulations of random walk dispersal of magnetic features were compared against the predictions of the diffusion treatment. Results: We confirm the validity of the diffusion approximation to describe flux dispersal on large scales. We find that the inflows enhance flux cancellation, but at the same time affect the latitudinal separation of the polarities of the bipolar region. In most cases the latitudinal separation is limited by the inflows, resulting in a reduction of the axial dipole moment of the BMR. However, when the initial tilt angle of the BMR is small, the inflows produce an increase in latitudinal separation that leads to an increase in the axial dipole moment in spite of the enhanced flux destruction. This can give rise to a tilt of the BMR even when the BMR was originally aligned parallel to the equator.

  4. Mosaic HIV envelope immunogenic polypeptides

    Science.gov (United States)

    Korber, Bette T. M.; Gnanakaran, S.; Perkins, Simon; Sodroski, Joseph; Haynes, Barton

    2018-01-02

    Disclosed herein are mosaic HIV envelope (Env) polypeptides that can elicit an immune response to HIV (such as cytotoxic T cell (CTL), helper T cell, and/or humoral responses). Also disclosed are sets of the disclosed mosaic Env polypeptides, which include two or more (for example, three) of the polypeptides. Also disclosed herein are methods for treating or inhibiting HIV in a subject including administering one or more of the disclosed immunogenic polypeptides or compositions to a subject infected with HIV or at risk of HIV infection. In some embodiments, the methods include inducing an immune response to HIV in a subject comprising administering to the subject at least one (such as two, three, or more) of the immunogenic polypeptides or at least one (such as two, three, or more) nucleic acids encoding at least one of the immunogenic polypeptides disclosed herein.

  5. Implementation of an Improved Safe Operating Envelope

    International Nuclear Information System (INIS)

    Prime, Robyn; McIntyre, Mark; Reeves, David

    2008-01-01

    This paper is a continuation of the paper presented at IYNC 2004 on 'The Definition of a Safe Operating Envelope'. The current paper concentrates on the implementation process of the Safe Operating Envelope employed at the Point Lepreau Generating Station. (authors)

  6. Physical properties of the red giant envelopes

    Energy Technology Data Exchange (ETDEWEB)

    Maciel, W J [Instituto de Astronomia e Geofisico da Universidade de Sao Paulo (Brazil)

    1978-12-01

    In this work, several model envelopes are calculated for cool giant stars with mass loss due to the action of stellar radiation pressure on molecules and grains. Molecular profiles as well as average values of some physical parameters of the envelopes are obtained.

  7. Physical properties of the red giant envelopes

    International Nuclear Information System (INIS)

    Maciel, W.J.

    1978-01-01

    In this work, several model envelopes are calculated for cool giant stars with mass loss due to the action of stellar radiation pressure on molecules and grains. Molecular profiles as well as average values of some physical parameters of the envelopes are obtained [pt

  8. Implementation of an Improved Safe Operating Envelope

    Energy Technology Data Exchange (ETDEWEB)

    Prime, Robyn; McIntyre, Mark [NB Power Nuclear, P.O. Box 600, Lepreau, NB (Canada); Reeves, David [Atlantic Nuclear Services Ltd., PO Box 1268 Fredericton, NB (Canada)

    2008-07-01

    This paper is a continuation of the paper presented at IYNC 2004 on 'The Definition of a Safe Operating Envelope'. The current paper concentrates on the implementation process of the Safe Operating Envelope employed at the Point Lepreau Generating Station. (authors)

  9. Induced wave propagation from a vibrating containment envelope

    International Nuclear Information System (INIS)

    Stout, R.B.; Thigpen, L.; Rambo, J.T.

    1985-09-01

    Low frequency wave forms are observed in the particle velocity measurements around the cavity and containment envelope formed by an underground nuclear test. The vibration solution for a spherical shell is used to formulate a model for the low frequency wave that propagates outward from this region. In this model the containment envelope is the zone of material that is crushed by the compressive shock wave of the nuclear explosion. The containment envelope is approximated by a spherical shell of material. The material in the spherical shell is densified and is given a relatively high kinetic energy density because of the high compressive stress and particle velocity of the shock wave. After the shock wave has propagated through the spherical shell, the spherical shell vibrates in order to dissipate the kinetic energy acquired from the shock wave. Based on the model, the frequency of vibration depends on the dimensions and material properties of the spherical shell. The model can also be applied in an inverse mode to obtain global estimates of averaged materials properties. This requires using experimental data and semi-empirical relationships involving the material properties. A particular case of estimating a value for shear strength is described. Finally, the oscillation time period of the lowest frequency from five nuclear tests is correlated with the energy of the explosion. The correlation provides another diagnostic to estimate the energy of a nuclear explosion. Also, the longest oscillation time period measurement provides additional experimental data that can be used to assess and validate various computer models. 11 refs., 2 figs

  10. Dust Coagulation in Infalling Protostellar Envelopes I. Compact Grains

    Science.gov (United States)

    Yorke, H.; Lin, D.; Suttner, G.

    1999-01-01

    Dust plays a key role in the optical, thermodynamic and gas dynamical behavior of collapsing molecular cores. Because of relative velocities of the individual dust grains, coagulation and shattering can modify the grain size distribution and -- due to corresponding changes in the medium's opacity significantly -- influence the evolution during early phases of star formation.

  11. CCS Observations of the Protostellar Envelope of B335

    Science.gov (United States)

    Velusamy, T.; Kuiper, T. B. H.; Langer, W. D.

    1995-01-01

    Knowledge of the density, velocity and chemical profiles around protostars is of fundamental importance for testing dynamical models of protostar evolution and understanding the nature of the material falling onto circumstellar disks. Presented are single dish and interferometric spectral line observations of CCS towards the core of B335, a classic example of a young, low mass stellar object.

  12. Injection envelope matching in storage rings

    International Nuclear Information System (INIS)

    Minty, M.G.; Spence, W.L.

    1995-05-01

    The shape and size of the transverse phase space injected into a storage ring can be deduced from turn-by-turn measurements of the transient behavior of the beam envelope in the ring. Envelope oscillations at 2 x the β-tron frequency indicate the presence of a β-mismatch, while envelope oscillations at the β-tron frequency are the signature of a dispersion function mismatch. Experiments in injection optimization using synchrotron radiation imaging of the beam and a fast-gated camera at the SLC damping rings are reported

  13. MHTGR thermal performance envelopes: Reliability by design

    International Nuclear Information System (INIS)

    Etzel, K.T.; Howard, W.W.; Zgliczynski, J.B.

    1992-05-01

    This document discusses thermal performance envelopes which are used to specify steady-state design requirements for the systems of the Modular High Temperature Gas-Cooled Reactor to maximize plant performance reliability with optimized design. The thermal performance envelopes are constructed around the expected operating point accounting for uncertainties in actual plant as-built parameters and plant operation. The components are then designed to perform successfully at all points within the envelope. As a result, plant reliability is maximized by accounting for component thermal performance variation in the design. The design is optimized by providing a means to determine required margins in a disciplined and visible fashion

  14. Analytical study of envelope modes for a fully depressed beam in solenoidal and quadrupole periodic transport channels

    International Nuclear Information System (INIS)

    Bukh, Boris; Lund, Steven M.

    2003-01-01

    We present an analysis of envelope perturbations evolving in the limit of a fully space-charge depressed (zero emittance) beam in periodic, thin-lens focusing channels. Both periodic solenoidal and FODO quadrupole focusing channels are analyzed. The phase advance and growth rate of normal mode perturbations are analytically calculated as a function of the undepressed particle phase advance to characterize the evolution of envelope perturbations

  15. In situ accretion of gaseous envelopes on to planetary cores embedded in evolving protoplanetary discs

    Science.gov (United States)

    Coleman, Gavin A. L.; Papaloizou, John C. B.; Nelson, Richard P.

    2017-09-01

    The core accretion hypothesis posits that planets with significant gaseous envelopes accreted them from their protoplanetary discs after the formation of rocky/icy cores. Observations indicate that such exoplanets exist at a broad range of orbital radii, but it is not known whether they accreted their envelopes in situ, or originated elsewhere and migrated to their current locations. We consider the evolution of solid cores embedded in evolving viscous discs that undergo gaseous envelope accretion in situ with orbital radii in the range 0.1-10 au. Additionally, we determine the long-term evolution of the planets that had no runaway gas accretion phase after disc dispersal. We find the following. (I) Planets with 5 M⊕ cores never undergo runaway accretion. The most massive envelope contained 2.8 M⊕ with the planet orbiting at 10 au. (II) Accretion is more efficient on to 10 M⊕ and 15 M⊕ cores. For orbital radii ap ≥ 0.5 au, 15 M⊕ cores always experienced runaway gas accretion. For ap ≥ 5 au, all but one of the 10 M⊕ cores experienced runaway gas accretion. No planets experienced runaway growth at ap = 0.1 au. (III) We find that, after disc dispersal, planets with significant gaseous envelopes cool and contract on Gyr time-scales, the contraction time being sensitive to the opacity assumed. Our results indicate that Hot Jupiters with core masses ≲15 M⊕ at ≲0.1 au likely accreted their gaseous envelopes at larger distances and migrated inwards. Consistently with the known exoplanet population, super-Earths and mini-Neptunes at small radii during the disc lifetime, accrete only modest gaseous envelopes.

  16. The species velocity of trees in Alaska

    Science.gov (United States)

    Morrison, B. D.; Napier, J.; de Lafontaine, G.; Heath, K.; Li, B.; Hu, F.; Greenberg, J. A.

    2017-12-01

    Anthropogenic climate change has motivated interest in the paleo record to enhance our knowledge about past vegetation responses to climate change and help understand potential responses in the future. Additionally, polar regions currently experience the most rapid rates of climate change globally, prompting concern over changes in the ecological composition of high latitude ecosystems. Recent analyses have attempted to construct methods to estimate a species' ability to track climate change by computing climate velocity; a measure of the rate of climate displacement across a landscape which may indicate the speed an organism must migrate to keep pace with climate change. However, a challenge to using climate velocity in understanding range shifts is a lack of species-specificity in the velocity calculations: climate velocity does not actually use any species data in its analysis. To solve the shortcomings of climate velocity in estimating species displacement rates, we computed the "species velocity" of white spruce, green and grey alder populations across the state of Alaska from the Last Glacial Maximum (LGM) to today. Species velocity represents the rate and direction a species is required to migrate to keep pace with a changing climate following the LGM. We used a species distribution model to determine past and present white spruce and alder distributions using statistically downscaled climate data at 60m. Species velocity was then derived from the change in species distribution per year by the change in distribution over Alaska (km/yr). High velocities indicate locations where the species environmental envelope is changing drastically and must disperse rapidly to survive climate change. As a result, high velocity regions are more vulnerable to distribution shifts and higher risk of local extinction. Conversely, low species velocities indicate locations where the local climate envelope is shifting relatively slowly, reducing the stress to disperse quickly

  17. Constructing canonical bases of quantized enveloping algebras

    OpenAIRE

    Graaf, W.A. de

    2001-01-01

    An algorithm for computing the elements of a given weight of the canonical basis of a quantized enveloping algebra is described. Subsequently, a similar algorithm is presented for computing the canonical basis of a finite-dimensional module.

  18. IR photometry results and dust envelope model for symbiotic Mira star candidate V 335 Vul

    Science.gov (United States)

    Bogdanov, M. B.; Taranova, O. G.; Shenavrin, V. I.

    2017-10-01

    We present the results of JHKLM-photometry for the symbiotic Mira star candidate V 335 Vul. Based on the average flux data, supplemented by IRAS, MSX, AKARI, and WISE mid-IR observations, we calculated a model of a spherically symmetric dust envelope of the star, made up of amorphous carbon and silicon carbide particles. The optical depth of the envelope in the visible range with a dust temperature at the inner boundary of T 1 = 1300 K is τ V = 0.58. For an envelope expansion velocity of 26.5 km s-1, the estimated mass loss rate is equal to 5.7 × 10-7 M ⊙ yr-1.

  19. Creating a Lunar EVA Work Envelope

    Science.gov (United States)

    Griffin, Brand N.; Howard, Robert; Rajulu, Sudhakar; Smitherman, David

    2009-01-01

    A work envelope has been defined for weightless Extravehicular Activity (EVA) based on the Space Shuttle Extravehicular Mobility Unit (EMU), but there is no equivalent for planetary operations. The weightless work envelope is essential for planning all EVA tasks because it determines the location of removable parts, making sure they are within reach and visibility of the suited crew member. In addition, using the envelope positions the structural hard points for foot restraints that allow placing both hands on the job and provides a load path for reacting forces. EVA operations are always constrained by time. Tasks are carefully planned to ensure the crew has enough breathing oxygen, cooling water, and battery power. Planning first involves computers using a virtual work envelope to model tasks, next suited crew members in a simulated environment refine the tasks. For weightless operations, this process is well developed, but planetary EVA is different and no work envelope has been defined. The primary difference between weightless and planetary work envelopes is gravity. It influences anthropometry, horizontal and vertical mobility, and reaction load paths and introduces effort into doing "overhead" work. Additionally, the use of spacesuits other than the EMU, and their impacts on range of motion, must be taken into account. This paper presents the analysis leading to a concept for a planetary EVA work envelope with emphasis on lunar operations. There is some urgency in creating this concept because NASA has begun building and testing development hardware for the lunar surface, including rovers, habitats and cargo off-loading equipment. Just as with microgravity operations, a lunar EVA work envelope is needed to guide designers in the formative stages of the program with the objective of avoiding difficult and costly rework.

  20. The Arabidopsis Nuclear Pore and Nuclear Envelope

    OpenAIRE

    Meier, Iris; Brkljacic, Jelena

    2010-01-01

    The nuclear envelope is a double membrane structure that separates the eukaryotic cytoplasm from the nucleoplasm. The nuclear pores embedded in the nuclear envelope are the sole gateways for macromolecular trafficking in and out of the nucleus. The nuclear pore complexes assembled at the nuclear pores are large protein conglomerates composed of multiple units of about 30 different nucleoporins. Proteins and RNAs traffic through the nuclear pore complexes, enabled by the interacting activities...

  1. PROBING SHOCK BREAKOUT AND PROGENITORS OF STRIPPED-ENVELOPE SUPERNOVAE THROUGH THEIR EARLY RADIO EMISSIONS

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Keiichi, E-mail: keiichi.maeda@ipmu.jp [Kavli Institute for the Physics and Mathematics of the Universe (Kavli-IPMU), Todai Institutes for Advanced Study (TODIAS), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)

    2013-01-01

    We study properties of early radio emission from stripped-envelope supernovae (SNe; those of Type IIb/Ib/Ic). We suggest there is a sub-class of stripped-envelope SNe based on their radio properties, including the optically well-studied Type Ic SNe (SNe Ic) 2002ap and 2007gr, showing a rapid rise to a radio peak within {approx}10 days and reaching a low luminosity (at least an order of magnitude fainter than a majority of SNe IIb/Ib/Ic). They show a decline after the peak that is shallower than that of other stripped-envelope SNe while their spectral index is similar. We show that all these properties are naturally explained if the circumstellar material (CSM) density is low and therefore the forward shock is expanding into the CSM without deceleration. Since the forward shock velocity in this situation, as estimated from the radio properties, still records the maximum velocity of the SN ejecta following the shock breakout, observing these SNe in radio wavelengths provides new diagnostics on the nature of both the breakout and the progenitor which otherwise require a quite rapid follow-up in other wavelengths. The inferred post-shock breakout velocities of SNe Ic 2002ap and 2007gr are sub-relativistic, {approx}0.3c. These are higher than that inferred for SN II 1987A, in line with suggested compact progenitors. However, these are lower than expected for a Wolf-Rayet (W-R) progenitor. It may reflect an as yet unresolved nature of the progenitors just before the explosion, and we suggest that the W-R progenitor envelopes might have been inflated which could quickly reduce the maximum ejecta velocity from the initial shock breakout velocity.

  2. All the Universe in an envelope

    CERN Multimedia

    2007-01-01

    Do you know which force is hidden in an envelope or how many billions of years old are the atoms it contains? You will find the answers to these (curious) questions in a post office in the Pays de Gex. The French postal services of the Pays de Gex are again issuing pre-paid envelopes in collaboration with CERN (see Bulletin No. 24/2006). The new series presents some of the concepts of modern physics in an amazing way by showing what you can learn about the Universe with a single envelope. Packets of ten pre-stamped envelopes, each carrying a statement on fundamental physics, will be on sale from 7 July onwards. To learn more about the physics issues presented on the envelopes, people are invited to go to the CERN Web site where they will find the explanations. Five thousand envelopes will be put on sale in July and five thousand more during the French "Fête de la science" in October. They will be available from five post offices in the Pays de Gex (F...

  3. Genetic Diversity of Koala Retroviral Envelopes

    Directory of Open Access Journals (Sweden)

    Wenqin Xu

    2015-03-01

    Full Text Available Genetic diversity, attributable to the low fidelity of reverse transcription, recombination and mutation, is an important feature of infectious retroviruses. Under selective pressure, such as that imposed by superinfection interference, gammaretroviruses commonly adapt their envelope proteins to use alternative receptors to overcome this entry block. The first characterized koala retroviruses KoRV subgroup A (KoRV-A were remarkable in their absence of envelope genetic variability. Once it was determined that KoRV-A was present in all koalas in US zoos, regardless of their disease status, we sought to isolate a KoRV variant whose presence correlated with neoplastic malignancies. More than a decade after the identification of KoRV-A, we isolated a second subgroup of KoRV, KoRV-B from koalas with lymphomas. The envelope proteins of KoRV-A and KoRV-B are sufficiently divergent to confer the ability to bind and employ distinct receptors for infection. We have now obtained a number of additional KoRV envelope variants. In the present studies we report these variants, and show that they differ from KoRV-A and KoRV-B envelopes in their host range and superinfection interference properties. Thus, there appears to be considerable variation among KoRVs envelope genes suggesting genetic diversity is a factor following the KoRV-A infection process.

  4. Ion-acoustic envelope modes in a degenerate relativistic electron-ion plasma

    Energy Technology Data Exchange (ETDEWEB)

    McKerr, M.; Kourakis, I. [Centre for Plasma Physics, School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN Belfast, Northern Ireland (United Kingdom); Haas, F. [Instituto de Física, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, RS (Brazil)

    2016-05-15

    A self-consistent relativistic two-fluid model is proposed for one-dimensional electron-ion plasma dynamics. A multiple scales perturbation technique is employed, leading to an evolution equation for the wave envelope, in the form of a nonlinear Schrödinger type equation (NLSE). The inclusion of relativistic effects is shown to introduce density-dependent factors, not present in the non-relativistic case—in the conditions for modulational instability. The role of relativistic effects on the linear dispersion laws and on envelope soliton solutions of the NLSE is discussed.

  5. Formation of a Keplerian disk in the infalling envelope around L1527 IRS: transformation from infalling motions to Kepler motions

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, Nagayoshi [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A' ohoku Place, Hilo, HI 96720 (United States); Saigo, Kazuya [Chile Observatory, National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan); Aso, Yusuke; Koyamatsu, Shin [Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Aikawa, Yuri [Department of Earth and Planetary Sciences, Kobe University, Kobe 657-8501 (Japan); Machida, Masahiro N. [Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, Fukuoka 812-8581 (Japan); Saito, Masao [Joint ALMA Observatory, Ave. Alonso de Cordova 3107, Vitacura, Santiago (Chile); Takahashi, Sanemichi Z. [Department of Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Takakuwa, Shigehisa; Yen, Hsi-Wei [Academia Sinica Institute of Astronomy and Astrophysics, PO Box 23-141, Taipei 10617, Taiwan (China); Tomida, Kengo [Department of Astronomical Science, Princeton University, Princeton, NJ 08544 (United States); Tomisaka, Kohji, E-mail: nohashi@naoj.org [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)

    2014-12-01

    We report Atacama Large Millimeter/submillimeter Array (ALMA) cycle 0 observations of the C{sup 18}O (J = 2-1), SO (J{sub N} = 6{sub 5}-5{sub 4}), and the 1.3 mm dust continuum toward L1527 IRS, a class 0 solar-type protostar surrounded by an infalling and rotating envelope. C{sup 18}O emission shows strong redshifted absorption against the bright continuum emission associated with L1527 IRS, strongly suggesting infall motions in the C{sup 18}O envelope. The C{sup 18}O envelope also rotates with a velocity mostly proportional to r {sup –1}, where r is the radius, whereas the rotation profile at the innermost radius (∼54 AU) may be shallower than r {sup –1}, suggestive of formation of a Keplerian disk around the central protostar of ∼0.3 M {sub ☉} in dynamical mass. SO emission arising from the inner part of the C{sup 18}O envelope also shows rotation in the same direction as the C{sup 18}O envelope. The rotation is, however, rigid-body-like, which is very different from the differential rotation shown by C{sup 18}O. In order to explain the line profiles and the position-velocity (PV) diagrams of C{sup 18}O and SO observed, simple models composed of an infalling envelope surrounding a Keplerian disk of 54 AU in radius orbiting a star of 0.3 M {sub ☉} are examined. It is found that in order to reproduce characteristic features of the observed line profiles and PV diagrams, the infall velocity in the model has to be smaller than the free-fall velocity yielded by a star of 0.3 M {sub ☉}. Possible reasons for the reduced infall velocities are discussed.

  6. Solitary Alfven wave envelopes and the modulational instability

    International Nuclear Information System (INIS)

    Kennel, C.F.

    1987-06-01

    The derivative nonlinear Schroedinger equation describes the modulational instability of circularly polarized dispersive Alfven wave envelopes. It also may be used to determine the properties of finite amplitude localized stationary wave envelopes. Such envelope solitons exist only in conditions of modulational stability. This leaves open the question of whether, and if so, how, the modulational instability produces envelope solitons. 12 refs

  7. Formation of polycyclic aromatic hydrocarbons in circumstellar envelopes

    International Nuclear Information System (INIS)

    Frenklach, M.; Feigelson, E.D.

    1989-01-01

    Production of polycyclic aromatic hydrocarbons in carbon-rich circumstellar envelopes was investigated using a kinetic approach. A detailed chemical reaction mechanism of gas-phase PAH formation and growth, containing approximately 100 reactions of 40 species, was numerically solved under the physical conditions expected in cool stellar winds. The chemistry is based on studies of soot production in hydrocarbon pyrolysis and combustion. Several first-ring and second-ring cyclization processes were considered. A linear lumping algorithm was used to describe PAH growth beyond the second aromatic ring. PAH production using this mechanism was examined with respect to a grid of idealized constant velocity stellar winds as well as several published astrophysical models. The basic result is that the onset of PAH production in the interstellar envelopes is predicted to occur within the temperature interval of 1100 to 900 K. The absolute amounts of the PAHs formed, however, are very sensitive to a number of parameters, both chemical and astrophysical, whose values are not accurately known. Astrophysically meaningful quantities of PAHs require particularly dense and slow stellar winds and high initial acetylene abundance. It is suggested that most of the PAHs may be produced in a relatively small fraction of carbon-rich red giants. 87 refs

  8. Envelope method for determination of the ion linear accelerator acceptance

    International Nuclear Information System (INIS)

    Sharshanov, A.A.; Goncharenko, I.I.; Revutskij, E.I.

    1974-01-01

    The acceptance defined by the slit u 2 2 in space u, ν, z (u=coordinate of the accelerated particle in the direction perpendicular to the accelerator axis, ν=ratio of the transverse particle velocity component to the longitudinal component, z=accelerator axis, a=dimensions of slit) represents a convex curvilinear polygon with centre of symmetry at the origin of the co-ordinates. The sides of the polygon are sections of ellipses and straight lines, the ellipses being part of an envelope to the set of proto-types of all cross-sections of the slit in planes z=3, where 0<=xi<=z and z is the length of the accelerator, and the straight lines are tangents to the ends of the envelope. In the paper the equations of the ellipses forming the sides of the polygon are written using an elementary variable matrix of the accelerator structure, and the co-ordinates of the polygon apexes are found. A numerical value is derived for the area of the polygon for one transverse co-ordinate of the particular accelerator, the pre-stripping section of the LUMZI-10. (author)

  9. Radial extension of drift waves in presence of velocity profiles

    International Nuclear Information System (INIS)

    Sen, S.; Weiland, J.

    1994-01-01

    The effect of a radially varying poloidal velocity field on the recently found radially extended toroidal drift waves is investigated analytically. The role of velocity curvature (υ φ '') is found to have robust effects on the radial model structure of the mode. For a positive value of the curvature (Usually found in the H-mode edges) the radial model envelope, similar to the sheared slab case, becomes fully outgoing. The mode is therefore stable. On the other hand, for a negative value of the curvature (usually observed in the L-mode edges) all the characteristics of conventional drift waves return back. The radial mode envelope reduces to a localized Gaussian shape and the mode is therefore unstable again for typical (magnetic) shear values in tokamaks. Velocity shear (υ φ ??) on the other hand is found to have rather insignificant role both in determining the radial model structure and stability

  10. Flight envelope protection system for unmanned aerial vehicles

    KAUST Repository

    Claudel, Christian G.

    2016-04-28

    Systems and methods to protect the flight envelope in both manual flight and flight by a commercial autopilot are provided. A system can comprise: an inertial measurement unit (IMU); a computing device in data communication with the IMU; an application executable by the computing device comprising: logic that estimates an angle of attack; a slip angle; and a speed of an unmanned aerial vehicle (UAV) based at least in part on data received from the UAV. A method can comprise estimating, via a computing device, flight data of a UAV based at least in part on data received from an IMU; comparing the estimated flight data with measured flight data; and triggering an error indication in response to a determination that the measured flight data exceeds a predefined deviation of the estimated flight data. The estimated speed can comprise an estimated airspeed, vertical speed and/or ground velocity.

  11. A stochastic differential equation framework for the turbulent velocity field

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Schmiegel, Jürgen

    We discuss a stochastic differential equation, as a modelling framework for the turbulent velocity field, that is capable of capturing basic stylized facts of the statistics of velocity increments. In particular, we focus on the evolution of the probability density of velocity increments...

  12. Inhibition of enveloped viruses infectivity by curcumin.

    Directory of Open Access Journals (Sweden)

    Tzu-Yen Chen

    Full Text Available Curcumin, a natural compound and ingredient in curry, has antiinflammatory, antioxidant, and anticarcinogenic properties. Previously, we reported that curcumin abrogated influenza virus infectivity by inhibiting hemagglutination (HA activity. This study demonstrates a novel mechanism by which curcumin inhibits the infectivity of enveloped viruses. In all analyzed enveloped viruses, including the influenza virus, curcumin inhibited plaque formation. In contrast, the nonenveloped enterovirus 71 remained unaffected by curcumin treatment. We evaluated the effects of curcumin on the membrane structure using fluorescent dye (sulforhodamine B; SRB-containing liposomes that mimic the viral envelope. Curcumin treatment induced the leakage of SRB from these liposomes and the addition of the influenza virus reduced the leakage, indicating that curcumin disrupts the integrity of the membranes of viral envelopes and of liposomes. When testing liposomes of various diameters, we detected higher levels of SRB leakage from the smaller-sized liposomes than from the larger liposomes. Interestingly, the curcumin concentration required to reduce plaque formation was lower for the influenza virus (approximately 100 nm in diameter than for the pseudorabies virus (approximately 180 nm and the vaccinia virus (roughly 335 × 200 × 200 nm. These data provide insights on the molecular antiviral mechanisms of curcumin and its potential use as an antiviral agent for enveloped viruses.

  13. Featured Image: Orbiting Stars Share an Envelope

    Science.gov (United States)

    Kohler, Susanna

    2016-03-01

    This beautiful series of snapshots from a simulation (click for a better look!) shows what happens when two stars in a binary system become enclosed in the same stellar envelope. In this binary system, one of the stars has exhausted its hydrogen fuel and become a red giant, complete with an expanding stellar envelope composed of hydrogen and helium. Eventually, the envelope expands so much that the companion star falls into it, where it releases gravitational potential energy into the common envelope. A team led by Sebastian Ohlmann (Heidelberg Institute for Theoretical Studies and University of Wrzburg) recently performed hydrodynamic simulations of this process. Ohlmann and collaborators discovered that the energy release eventually triggers large-scale flow instabilities, which leads to turbulence within the envelope. This process has important consequences for how these systems next evolve (for instance, determining whether or not a supernova occurs!). You can check out the authors video of their simulated stellar inspiral below, or see their paper for more images and results from their study.CitationSebastian T. Ohlmann et al 2016 ApJ 816 L9. doi:10.3847/2041-8205/816/1/L9

  14. Inhibition of Enveloped Viruses Infectivity by Curcumin

    Science.gov (United States)

    Wen, Hsiao-Wei; Ou, Jun-Lin; Chiou, Shyan-Song; Chen, Jo-Mei; Wong, Min-Liang; Hsu, Wei-Li

    2013-01-01

    Curcumin, a natural compound and ingredient in curry, has antiinflammatory, antioxidant, and anticarcinogenic properties. Previously, we reported that curcumin abrogated influenza virus infectivity by inhibiting hemagglutination (HA) activity. This study demonstrates a novel mechanism by which curcumin inhibits the infectivity of enveloped viruses. In all analyzed enveloped viruses, including the influenza virus, curcumin inhibited plaque formation. In contrast, the nonenveloped enterovirus 71 remained unaffected by curcumin treatment. We evaluated the effects of curcumin on the membrane structure using fluorescent dye (sulforhodamine B; SRB)-containing liposomes that mimic the viral envelope. Curcumin treatment induced the leakage of SRB from these liposomes and the addition of the influenza virus reduced the leakage, indicating that curcumin disrupts the integrity of the membranes of viral envelopes and of liposomes. When testing liposomes of various diameters, we detected higher levels of SRB leakage from the smaller-sized liposomes than from the larger liposomes. Interestingly, the curcumin concentration required to reduce plaque formation was lower for the influenza virus (approximately 100 nm in diameter) than for the pseudorabies virus (approximately 180 nm) and the vaccinia virus (roughly 335 × 200 × 200 nm). These data provide insights on the molecular antiviral mechanisms of curcumin and its potential use as an antiviral agent for enveloped viruses. PMID:23658730

  15. THE PROPERTIES OF HEAVY ELEMENTS IN GIANT PLANET ENVELOPES

    Energy Technology Data Exchange (ETDEWEB)

    Soubiran, François; Militzer, Burkhard [Department of Earth and Planetary Science, University of California, Berkeley, CA 94720 (United States)

    2016-09-20

    The core-accretion model for giant planet formation suggests a two-layer picture for the initial structure of Jovian planets, with heavy elements in a dense core and a thick H–He envelope. Late planetesimal accretion and core erosion could potentially enrich the H–He envelope in heavy elements, which is supported by the threefold solar metallicity that was measured in Jupiter’s atmosphere by the Galileo entry probe. In order to reproduce the observed gravitational moments of Jupiter and Saturn, models for their interiors include heavy elements, Z , in various proportions. However, their effect on the equation of state of the hydrogen–helium mixtures has not been investigated beyond the ideal mixing approximation. In this article, we report results from ab initio simulations of fully interacting H–He– Z mixtures in order to characterize their equation of state and to analyze possible consequences for the interior structure and evolution of giant planets. Considering C, N, O, Si, Fe, MgO, and SiO{sub 2}, we show that the behavior of heavy elements in H–He mixtures may still be represented by an ideal mixture if the effective volumes and internal energies are chosen appropriately. In the case of oxygen, we also compute the effect on the entropy. We find the resulting changes in the temperature–pressure profile to be small. A homogeneous distribution of 2% oxygen by mass changes the temperature in Jupiter’s interior by only 80 K.

  16. Optimum moisture levels for biodegradation of mortality composting envelope materials.

    Science.gov (United States)

    Ahn, H K; Richard, T L; Glanville, T D

    2008-01-01

    Moisture affects the physical and biological properties of compost and other solid-state fermentation matrices. Aerobic microbial systems experience different respiration rates (oxygen uptake and CO2 evolution) as a function of moisture content and material type. In this study the microbial respiration rates of 12 mortality composting envelope materials were measured by a pressure sensor method at six different moisture levels. A wide range of respiration (1.6-94.2mg O2/g VS-day) rates were observed for different materials, with alfalfa hay, silage, oat straw, and turkey litter having the highest values. These four envelope materials may be particularly suitable for improving internal temperature and pathogen destruction rates for disease-related mortality composting. Optimum moisture content was determined based on measurements across a range that spans the maximum respiration rate. The optimum moisture content of each material was observed near water holding capacity, which ranged from near 60% to over 80% on a wet basis for all materials except a highly stabilized soil compost blend (optimum around 25% w.b.). The implications of the results for moisture management and process control strategies during mortality composting are discussed.

  17. Computation of Phase Equilibrium and Phase Envelopes

    DEFF Research Database (Denmark)

    Ritschel, Tobias Kasper Skovborg; Jørgensen, John Bagterp

    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......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...... 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...

  18. Boundaries, injective envelopes, and reduced crossed products

    DEFF Research Database (Denmark)

    Bryder, Rasmus Sylvester

    In this dissertation, we study boundary actions, equivariant injective envelopes, as well as theideal structure of reduced crossed products. These topics have recently been linked to thestudy of C-simple groups, that is, groups with simple reduced group C-algebras.In joint work with Matthew Kennedy......, we consider reduced twisted crossed products overC-simple groups. For any twisted C-dynamical system over a C-simple group, we provethat there is a one-to-one correspondence between maximal invariant ideals in the underlyingC-algebra and maximal ideals in the reduced crossed product. When......*-algebras, and relate the intersection property for group actions on unital C*-algebras to the intersection property for theequivariant injective envelope. Moreover, we also prove that the equivariant injective envelopeof the centre of the injective envelope of a unital C*-algebra can be regarded as a C...

  19. A study of some Be star envelopes

    International Nuclear Information System (INIS)

    Kitchen, C.R.

    1976-01-01

    The envelope model and emission region radius of six Be stars have been determined from 36 lines on 15 spectra taken with the Isaac Newton telescope. The results have been compared with earlier determinations to search for changes with the time. No definite evidence for such changes has been found, although there may be an indication of a change in phi Per. A re-determination of the errors involved in the method of analysis shows that these are smaller than previously estimated and range from about 9% to 35% for both envelope model and emission region radius. (Auth.)

  20. Asymmetry of the SN 1987A envelope

    International Nuclear Information System (INIS)

    Chugaj, N.N.

    1991-01-01

    The origin of the peculiar structure in the profiles of the emission lines observed in the spectrum of SN 1987A, namely, (1) redshift of maxima, and (2) fine structure of hydrogen lines, is considered. Among the three proposed hypothesis for the redshift, at least two (electron scattering in the spherically-symmetric envelope, and geometrical effects in the fragmented envelope) have serious drawbacks. More favorable is the third hypothesis which invokes asymmetric distribution of 56 Ni and of the iron-peak elements

  1. Global Envelope Tests for Spatial Processes

    DEFF Research Database (Denmark)

    Myllymäki, Mari; Mrkvička, Tomáš; Grabarnik, Pavel

    2017-01-01

    Envelope tests are a popular tool in spatial statistics, where they are used in goodness-of-fit testing. These tests graphically compare an empirical function T(r) with its simulated counterparts from the null model. However, the type I error probability α is conventionally controlled for a fixed d......) the construction of envelopes for a deviation test. These new tests allow the a priori selection of the global α and they yield p-values. We illustrate these tests using simulated and real point pattern data....

  2. Global envelope tests for spatial processes

    DEFF Research Database (Denmark)

    Myllymäki, Mari; Mrkvička, Tomáš; Grabarnik, Pavel

    Envelope tests are a popular tool in spatial statistics, where they are used in goodness-of-fit testing. These tests graphically compare an empirical function T(r) with its simulated counterparts from the null model. However, the type I error probability α is conventionally controlled for a fixed......) the construction of envelopes for a deviation test. These new tests allow the a priori selection of the global α and they yield p-values. We illustrate these tests using simulated and real point pattern data....

  3. Glycosylation in HIV-1 envelope glycoprotein and its biological implications

    KAUST Repository

    Ho, Yung Shwen

    2013-08-01

    Glycosylation of HIV-1 envelope proteins (Env gp120/gp41) plays a vital role in viral evasion from the host immune response, which occurs through the masking of key neutralization epitopes and the presentation of the Env glycosylation as \\'self\\' to the host immune system. Env glycosylation is generally conserved, yet its continual evolution plays an important role in modulating viral infectivity and Env immunogenicity. Thus, it is believed that Env glycosylation, which is a vital part of the HIV-1 architecture, also controls intra- and inter-clade genetic variations. Discerning intra- and inter-clade glycosylation variations could therefore yield important information for understanding the molecular and biological differences between HIV clades and may assist in effectively designing Env-based immunogens and in clearly understanding HIV vaccines. This review provides an in-depth perspective of various aspects of Env glycosylation in the context of HIV-1 pathogenesis. © 2013 Future Medicine Ltd.

  4. Supernovae from massive stars with extended tenuous envelopes

    Science.gov (United States)

    Dessart, Luc; Yoon, Sung-Chul; Livne, Eli; Waldman, Roni

    2018-04-01

    Massive stars with a core-halo structure are interesting objects for stellar physics and hydrodynamics. Using simulations for stellar evolution, radiation hydrodynamics, and radiative transfer, we study the explosion of stars with an extended and tenuous envelope (i.e. stars in which 95% of the mass is contained within 10% or less of the surface radius). We consider both H-rich supergiant and He-giant progenitors resulting from close-binary evolution and dying with a final mass of 2.8-5 M⊙. An extended envelope causes the supernova (SN) shock to brake and a reverse shock to form, sweeping core material into a dense shell. The shock-deposited energy, which suffers little degradation from expansion, is trapped in ejecta layers of moderate optical depth, thereby enhancing the SN luminosity at early times. With the delayed 56Ni heating, we find that the resulting optical and near-IR light curves all exhibit a double-peak morphology. We show how an extended progenitor can explain the blue and featureless optical spectra of some Type IIb and Ib SNe. The dense shell formed by the reverse shock leads to line profiles with a smaller and near-constant width. This ejecta property can explain the statistically narrower profiles of Type IIb compared to Type Ib SNe, as well as the peculiar Hα profile seen in SN 1993J. At early times, our He-giant star explosion model shows a high luminosity, a blue colour, and featureless spectra reminiscent of the Type Ib SN 2008D, suggesting a low-mass progenitor.

  5. Nerve conduction velocity

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003927.htm Nerve conduction velocity To use the sharing features on this page, please enable JavaScript. Nerve conduction velocity (NCV) is a test to see ...

  6. HIV-1 subtype C envelope characteristics associated with divergent rates of chronic disease progression

    Directory of Open Access Journals (Sweden)

    Goulder Philip JR

    2010-11-01

    Full Text Available Abstract Background HIV-1 envelope diversity remains a significant challenge for the development of an efficacious vaccine. The evolutionary forces that shape the diversity of envelope are incompletely understood. HIV-1 subtype C envelope in particular shows significant differences and unique characteristics compared to its subtype B counterpart. Here we applied the single genome sequencing strategy of plasma derived virus from a cohort of therapy naïve chronically infected individuals in order to study diversity, divergence patterns and envelope characteristics across the entire HIV-1 subtype C gp160 in 4 slow progressors and 4 progressors over an average of 19.5 months. Results Sequence analysis indicated that intra-patient nucleotide diversity within the entire envelope was higher in slow progressors, but did not reach statistical significance (p = 0.07. However, intra-patient nucleotide diversity was significantly higher in slow progressors compared to progressors in the C2 (p = 0.0006, V3 (p = 0.01 and C3 (p = 0.005 regions. Increased amino acid length and fewer potential N-linked glycosylation sites (PNGs were observed in the V1-V4 in slow progressors compared to progressors (p = 0.009 and p = 0.02 respectively. Similarly, gp41 in the progressors was significantly longer and had fewer PNGs compared to slow progressors (p = 0.02 and p = 0.02 respectively. Positive selection hotspots mapped mainly to V1, C3, V4, C4 and gp41 in slow progressors, whereas hotspots mapped mainly to gp41 in progressors. Signature consensus sequence differences between the groups occurred mainly in gp41. Conclusions These data suggest that separate regions of envelope are under differential selective forces, and that envelope evolution differs based on disease course. Differences between slow progressors and progressors may reflect differences in immunological pressure and immune evasion mechanisms. These data also indicate that the pattern of envelope evolution

  7. Integrated Energy Design of the Building Envelope

    DEFF Research Database (Denmark)

    Nielsen, Martin Vraa

    This thesis describes the outcome of the PhD project Integrated energy design of the building envelope carried out through a combination of scientific dissemination reported through peer-reviewed journals and a wide range of affiliated projects involved in at an architectural firm. The research...

  8. SAFEGUARDS ENVELOPE: PREVIOUS WORK AND EXAMPLES

    International Nuclear Information System (INIS)

    Metcalf, Richard; Bevill, Aaron; Charlton, William; Bean, Robert

    2008-01-01

    The future expansion of nuclear power will require not just electricity production but fuel cycle facilities such as fuel fabrication and reprocessing plants. As large reprocessing facilities are built in various states, they must be built and operated in a manner to minimize the risk of nuclear proliferation. Process monitoring has returned to the spotlight as an added measure that can increase confidence in the safeguards of special nuclear material (SNM). Process monitoring can be demonstrated to lengthen the allowable inventory period by reducing accountancy requirements, and to reduce the false positive indications. The next logical step is the creation of a Safeguards Envelope, a set of operational parameters and models to maximize anomaly detection and inventory period by process monitoring while minimizing operator impact and false positive rates. A brief example of a rudimentary Safeguards Envelope is presented, and shown to detect synthetic diversions overlaying a measured processing plant data set. This demonstration Safeguards Envelope is shown to increase the confidence that no SNM has been diverted with minimal operator impact, even though it is based on an information sparse environment. While the foundation on which a full Safeguards Envelope can be built has been presented in historical demonstrations of process monitoring, several requirements remain yet unfulfilled. Future work will require reprocessing plant transient models, inclusion of 'non-traditional' operating data, and exploration of new methods of identifying subtle events in transient processes

  9. Multi-layered breathing architectural envelope

    DEFF Research Database (Denmark)

    Lund Larsen, Andreas; Foged, Isak Worre; Jensen, Rasmus Lund

    2014-01-01

    A multi layered breathing envelope is developed as a method of natural ventilation. The two main layers consist of mineral wool and air permeable concrete. The mineral wool works as a dynamic insulation and the permeable concrete as a heat recovery system with a high thermal mass for heat storage...

  10. Cost Allocation and Convex Data Envelopment

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Tind, Jørgen

    such as Data Envelopment Analysis (DEA). The convexity constraint of the BCC model introduces a non-zero slack in the objective function of the multiplier problem and we show that the cost allocation rules discussed in this paper can be used as candidates to allocate this slack value on to the input (or output...

  11. Test particle method for incorporation of the kinetic effects into the envelope simulations of Raman backscattering

    International Nuclear Information System (INIS)

    Hur, Min Sup; Suk, Hyyong

    2007-01-01

    A new test particle method is presented for self-consistent incorporation of the kinetic effects into the fluid three-wave model. One of the most important kinetic effects is the electron trapping and it has been found that the trapping affects significantly the behavior of Raman backscatter and Raman backward laser amplification. The conventional fluid three-wave model cannot reproduce the kinetic simulations in the trapping regime. The test particle scheme utilizes the same equations for the laser evolution as in the three-wave model. However, the plasma wave is treated by the envelope-kinetic equation, which consists of envelope evolution and the kinetic term. The core of the new scheme is employing test particles to compute the kinetic term self-consistently. The benchmarking results against the averaged particle-in-cell (aPIC) code show excellent agreements, and the computation speed gain over the aPIC is from 2 to 20 depending on parameters

  12. The velocity of sound

    International Nuclear Information System (INIS)

    Beyer, R.T.

    1985-01-01

    The paper reviews the work carried out on the velocity of sound in liquid alkali metals. The experimental methods to determine the velocity measurements are described. Tables are presented of reported data on the velocity of sound in lithium, sodium, potassium, rubidium and caesium. A formula is given for alkali metals, in which the sound velocity is a function of shear viscosity, atomic mass and atomic volume. (U.K.)

  13. Implications of the Galilean satellites ice envelope explosions. 3

    International Nuclear Information System (INIS)

    Agafonova, I.I.; Drobyshevski, E.M.

    1985-01-01

    Secondary explosions of the primary ice fragments ejected in the explosion of the electrolyzed massive ice envelopes of the Galilean satellites are capable of imparting velocities of up to 5 km s -1 to the secondary fragments. As a result, the secondary fragments can enter the orbits of the irregular satellites and the Trojan libration orbits. Since the icy mix of the fragments contains hydrocarbons and particulate material (silicates and the like), after ice sublimation from the surface layers the Trojans should reveal type C and RD spectra typical for Jupiter's irregular satellites, comet nuclei and other distant ice bodies of similar origin. Among the Trojans there cannot be rocky or metallic objects which are known to exist in the main asteroid belt. It is shown that a velocity perturbation of 150-200 m s -1 resulting from a purely mechanical impact of two bodies may be sufficient to move collision fragments from the orbits of the Trojans to horseshoe-shaped trajectories with a subsequent transfer to the cometary orbits of Jupiter's family. (Auth.)

  14. A theoretical study of problems in classical nova evolution

    International Nuclear Information System (INIS)

    Shankar, A.

    1990-01-01

    Three distinct issues in classical nova evolution are addressed with the aid of one- and two-dimensional numerical hydrodynamics. The effects of convection on nova outbursts are examined within the confines of the mixing length theory. It is found that increasing the efficiency of convection enhances the violence of the thermonuclear runaway (TNR). This also relates to the question of the feasibility of obtaining nova outbursts on magnetic white dwarfs among the AM Her systems. The effects of a strong magnetic field on the TNR are explored. The field interferes with the development of convection during the TNR, which results in lower ejection velocities. However, for field strengths typical of cataclysmic variables, the violence of strong outbursts is affected only moderately. The conditions necessary for the production of strong TNR's in the hibernation model of cataclysmic binary evolution are also examined. The feasibility of obtaining strong nova outbursts is investigated when the accretion rate during hibernation is decreased. It is found that a reduction (by a factor of 100) for periods of longer than a couple thousand years, is sufficient to ensure violent outbursts, even in the presence of large pre-outburst accretion rates. The effects of a common envelope phase (CEP) on the outburst are discussed. The motion of the secondary through an expanding common envelope is resisted by frictional drag. This dissipates both energy and angular momentum from the orbit inducing hydrodynamic motion. Significant departures are found to occur in the manner in which mass is lost when the effects of drag are taken into account. Specifically, a CEP is found to accelerate and enhance mass loss. Ejection is found to be concentrated in the orbital plane, with velocities of a few thousand km/sec

  15. Moisture accumulation in a building envelope

    Energy Technology Data Exchange (ETDEWEB)

    Forest, T.W.; Checkwitch, K.

    1988-09-01

    In a large number of cases, the failure of a building envelope can be traced to the accumulation of moisture. In a cold winter climate, characteristic of the Canadian prairies, moisture is deposited in the structure by the movement of warm, moist air through the envelope. Tests on the moisture accumulation in a building envelope were initiated in a test house at an Alberta research facility during the 1987/88 heating season. The indoor moisture generation rate was measured and compared with the value inferred from the measured air infiltration rate. With the flue open, the moisture generation rate was approximately 5.5 kg/d of which 0.7 kg/d entered the building envelope; the remainder was exhausted through the flue. With the flue blocked, the moisture generation rate decreased to 3.4 kg/d, while the amount of moisture migrating through the envelope increased to 4.0 kg/d. The moisture accumulation in wall panels located on the north and south face of the test house was also monitored. Moisture was allowed to enter the wall cavity via a hole in the drywall. The fiberglass insulation remained dry throughout the test period. The moisture content of the exterior sheathing of the north panel increased to a maximum of 18% wt in the vicinity of the hole, but quickly dried when the ambient temperatures increased towards the end of the season. The south panel showed very little moisture accumlation due to the effects of solar radiation. 14 refs., 9 figs.

  16. Validating predictions from climate envelope models.

    Directory of Open Access Journals (Sweden)

    James I Watling

    Full Text Available Climate envelope models are a potentially important conservation tool, but their ability to accurately forecast species' distributional shifts using independent survey data has not been fully evaluated. We created climate envelope models for 12 species of North American breeding birds previously shown to have experienced poleward range shifts. For each species, we evaluated three different approaches to climate envelope modeling that differed in the way they treated climate-induced range expansion and contraction, using random forests and maximum entropy modeling algorithms. All models were calibrated using occurrence data from 1967-1971 (t1 and evaluated using occurrence data from 1998-2002 (t2. Model sensitivity (the ability to correctly classify species presences was greater using the maximum entropy algorithm than the random forest algorithm. Although sensitivity did not differ significantly among approaches, for many species, sensitivity was maximized using a hybrid approach that assumed range expansion, but not contraction, in t2. Species for which the hybrid approach resulted in the greatest improvement in sensitivity have been reported from more land cover types than species for which there was little difference in sensitivity between hybrid and dynamic approaches, suggesting that habitat generalists may be buffered somewhat against climate-induced range contractions. Specificity (the ability to correctly classify species absences was maximized using the random forest algorithm and was lowest using the hybrid approach. Overall, our results suggest cautious optimism for the use of climate envelope models to forecast range shifts, but also underscore the importance of considering non-climate drivers of species range limits. The use of alternative climate envelope models that make different assumptions about range expansion and contraction is a new and potentially useful way to help inform our understanding of climate change effects on

  17. Validating predictions from climate envelope models

    Science.gov (United States)

    Watling, J.; Bucklin, D.; Speroterra, C.; Brandt, L.; Cabal, C.; Romañach, Stephanie S.; Mazzotti, Frank J.

    2013-01-01

    Climate envelope models are a potentially important conservation tool, but their ability to accurately forecast species’ distributional shifts using independent survey data has not been fully evaluated. We created climate envelope models for 12 species of North American breeding birds previously shown to have experienced poleward range shifts. For each species, we evaluated three different approaches to climate envelope modeling that differed in the way they treated climate-induced range expansion and contraction, using random forests and maximum entropy modeling algorithms. All models were calibrated using occurrence data from 1967–1971 (t1) and evaluated using occurrence data from 1998–2002 (t2). Model sensitivity (the ability to correctly classify species presences) was greater using the maximum entropy algorithm than the random forest algorithm. Although sensitivity did not differ significantly among approaches, for many species, sensitivity was maximized using a hybrid approach that assumed range expansion, but not contraction, in t2. Species for which the hybrid approach resulted in the greatest improvement in sensitivity have been reported from more land cover types than species for which there was little difference in sensitivity between hybrid and dynamic approaches, suggesting that habitat generalists may be buffered somewhat against climate-induced range contractions. Specificity (the ability to correctly classify species absences) was maximized using the random forest algorithm and was lowest using the hybrid approach. Overall, our results suggest cautious optimism for the use of climate envelope models to forecast range shifts, but also underscore the importance of considering non-climate drivers of species range limits. The use of alternative climate envelope models that make different assumptions about range expansion and contraction is a new and potentially useful way to help inform our understanding of climate change effects on species.

  18. Evolution of Deeply Embedded Protostars

    DEFF Research Database (Denmark)

    Frimann, Søren

    consequences for the evolution of protostellar systems. The sublimation of CO-ice from dust grains in the surrounding envelope can be used to trace accretion variability in protostars, because the increased heating during an accretion burst will cause the CO-ice to sublimate into the gas-phase where the excess...

  19. Novel Real-Time Flight Envelope Monitoring System, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is an aircraft flight envelope monitoring system that will provide real-time in-cockpit estimations of aircraft flight envelope boundaries....

  20. SYNTHETIC AGB EVOLUTION .1. A NEW MODEL

    NARCIS (Netherlands)

    GROENEWEGEN, MAT; DEJONG, T

    We have constructed a model to calculate in a synthetic way the evolution of stars on the asymptotic giant branch (AGB). The evolution is started at the first thermal pulse (TP) and is terminated when the envelope mass has been lost due to mass loss or when the core mass reaches the Chandrasekhar

  1. The effects of diffusion in hot subdwarf progenitors from the common envelope channel

    Science.gov (United States)

    Byrne, Conor M.; Jeffery, C. Simon; Tout, Christopher A.; Hu, Haili

    2018-04-01

    Diffusion of elements in the atmosphere and envelope of a star can drastically alter its surface composition, leading to extreme chemical peculiarities. We consider the case of hot subdwarfs, where surface helium abundances range from practically zero to almost 100 percent. Since hot subdwarfs can form via a number of different evolution channels, a key question concerns how the formation mechanism is connected to the present surface chemistry. A sequence of extreme horizontal branch star models was generated by producing post-common envelope stars from red giants. Evolution was computed with MESA from envelope ejection up to core-helium ignition. Surface abundances were calculated at the zero-age horizontal branch for models with and without diffusion. A number of simulations also included radiative levitation. The goal was to study surface chemistry during evolution from cool giant to hot subdwarf and determine when the characteristic subdwarf surface is established. Only stars leaving the giant branch close to core-helium ignition become hydrogen-rich subdwarfs at the zero-age horizontal branch. Diffusion, including radiative levitation, depletes the initial surface helium in all cases. All subdwarf models rapidly become more depleted than observations allow. Surface abundances of other elements follow observed trends in general, but not in detail. Additional physics is required.

  2. HOW THERMAL EVOLUTION AND MASS-LOSS SCULPT POPULATIONS OF SUPER-EARTHS AND SUB-NEPTUNES: APPLICATION TO THE KEPLER-11 SYSTEM AND BEYOND

    International Nuclear Information System (INIS)

    Lopez, Eric D.; Miller, Neil; Fortney, Jonathan J.

    2012-01-01

    We use models of thermal evolution and extreme ultraviolet (XUV) driven mass loss to explore the composition and history of low-mass, low-density transiting planets. We investigate the Kepler-11 system in detail and provide estimates of both the current and past planetary compositions. We find that an H/He envelope on Kepler-11b is highly vulnerable to mass loss. By comparing to formation models, we show that in situ formation of the system is extremely difficult. Instead we propose that it is a water-rich system of sub-Neptunes that migrated from beyond the snow line. For the broader population of observed planets, we show that there is a threshold in bulk planet density and incident flux above which no low-mass transiting planets have been observed. We suggest that this threshold is due to the instability of H/He envelopes to XUV-driven mass loss. Importantly, we find that this mass-loss threshold is well reproduced by our thermal evolution/contraction models that incorporate a standard mass-loss prescription. Treating the planets' contraction history is essential because the planets have significantly larger radii during the early era of high XUV fluxes. Over time low-mass planets with H/He envelopes can be transformed into water-dominated worlds with steam envelopes or rocky super-Earths. Finally, we use this threshold to provide likely minimum masses and radial-velocity amplitudes for the general population of Kepler candidates. Likewise, we use this threshold to provide constraints on the maximum radii of low-mass planets found by radial-velocity surveys.

  3. Inversion of Auditory Spectrograms, Traditional Spectrograms, and Other Envelope Representations

    DEFF Research Database (Denmark)

    Decorsière, Remi Julien Blaise; Søndergaard, Peter Lempel; MacDonald, Ewen

    2015-01-01

    Envelope representations such as the auditory or traditional spectrogram can be defined by the set of envelopes from the outputs of a filterbank. Common envelope extraction methods discard information regarding the fast fluctuations, or phase, of the signal. Thus, it is difficult to invert, or re...... to the framework is proposed, which leads to a more accurate inversion of traditional spectrograms...

  4. 200 Area Deactivation Project Facilities Authorization Envelope Document

    International Nuclear Information System (INIS)

    DODD, E.N.

    2000-01-01

    Project facilities as required by HNF-PRO-2701, Authorization Envelope and Authorization Agreement. The Authorization Agreements (AA's) do not identify the specific set of environmental safety and health requirements that are applicable to the facility. Therefore, the facility Authorization Envelopes are defined here to identify the applicable requirements. This document identifies the authorization envelopes for the 200 Area Deactivation

  5. 14 CFR 27.87 - Height-speed envelope.

    Science.gov (United States)

    2010-01-01

    ... applicable power failure condition in paragraph (b) of this section, a limiting height-speed envelope must be... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Height-speed envelope. 27.87 Section 27.87... STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Performance § 27.87 Height-speed envelope. (a) If there is any...

  6. Analysis of Building Envelope Construction in 2003 CBECS

    Energy Technology Data Exchange (ETDEWEB)

    Winiarski, David W.; Halverson, Mark A.; Jiang, Wei

    2007-06-01

    The purpose of this analysis is to determine "typical" building envelope characteristics for buildings built after 1980. We address three envelope components in this paper - roofs, walls, and window area. These typical building envelope characteristics were used in the development of DOE’s Reference Buildings .

  7. (2+1)-dimensional dissipation nonlinear Schrödinger equation for envelope Rossby solitary waves and chirp effect

    International Nuclear Information System (INIS)

    Li Jin-Yuan; Fang Nian-Qiao; Yuan Xiao-Bo; Zhang Ji; Xue Yu-Long; Wang Xue-Mu

    2016-01-01

    In the past few decades, the (1+1)-dimensional nonlinear Schrödinger (NLS) equation had been derived for envelope Rossby solitary waves in a line by employing the perturbation expansion method. But, with the development of theory, we note that the (1+1)-dimensional model cannot reflect the evolution of envelope Rossby solitary waves in a plane. In this paper, by constructing a new (2+1)-dimensional multiscale transform, we derive the (2+1)-dimensional dissipation nonlinear Schrödinger equation (DNLS) to describe envelope Rossby solitary waves under the influence of dissipation which propagate in a plane. Especially, the previous researches about envelope Rossby solitary waves were established in the zonal area and could not be applied directly to the spherical earth, while we adopt the plane polar coordinate and overcome the problem. By theoretical analyses, the conservation laws of (2+1)-dimensional envelope Rossby solitary waves as well as their variation under the influence of dissipation are studied. Finally, the one-soliton and two-soliton solutions of the (2+1)-dimensional NLS equation are obtained with the Hirota method. Based on these solutions, by virtue of the chirp concept from fiber soliton communication, the chirp effect of envelope Rossby solitary waves is discussed, and the related impact factors of the chirp effect are given. (paper)

  8. Shape Transformation of the Nuclear Envelope during Closed Mitosis.

    Science.gov (United States)

    Zhu, Qian; Zheng, Fan; Liu, Allen P; Qian, Jin; Fu, Chuanhai; Lin, Yuan

    2016-11-15

    The nuclear envelope (NE) in lower eukaryotes such as Schizosaccharomyces pombe undergoes large morphology changes during closed mitosis. However, which physical parameters are important in governing the shape evolution of the NE, and how defects in the dividing chromosomes/microtubules are reflected in those parameters, are fundamental questions that remain unresolved. In this study, we show that improper separation of chromosomes in genetically deficient cells leads to membrane tethering or asymmetric division in contrast to the formation of two equal-sized daughter nuclei in wild-type cells. We hypothesize that the poleward force is transmitted to the nuclear membrane through its physical contact with the separated sister chromatids at the two spindle poles. A theoretical model is developed to predict the morphology evolution of the NE where key factors such as the work done by the poleward force and bending and surface energies stored in the membrane have been taken into account. Interestingly, the predicted phase diagram, summarizing the dependence of nuclear shape on the size of the load transmission regions, and the pole-to-pole distance versus surface area relationship all quantitatively agree well with our experimental observations, suggesting that this model captures the essential physics involved in closed mitosis. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  9. Equivariant calculus in the differential envelope

    International Nuclear Information System (INIS)

    Kastler, D.

    1991-01-01

    The author shows how Z/2-graded cyclic cohomology is related to the equivariant calculus of S. Klimek, W. Kondracki, and A. Lesniewski (HUTMP 90/B247 (1990)). He uses the differential envelope of a complex unital differential algebra. After a presentation of fiber-preserved operators on equivariant functions valued in this algebra on a group he considers certain operators on this algebra. Finally he discusses explicitly the case G=Z/2. (HSI)

  10. Equivariant calculus in the differential envelope

    Energy Technology Data Exchange (ETDEWEB)

    Kastler, D. (Centre National de la Recherche Scientifique, 13 - Marseille (France). Centre de Physique Theorique)

    1991-01-01

    The author shows how Z/2-graded cyclic cohomology is related to the equivariant calculus of S. Klimek, W. Kondracki, and A. Lesniewski (HUTMP 90/B247 (1990)). He uses the differential envelope of a complex unital differential algebra. After a presentation of fiber-preserved operators on equivariant functions valued in this algebra on a group he considers certain operators on this algebra. Finally he discusses explicitly the case G=Z/2. (HSI).

  11. Digital image envelope: method and evaluation

    Science.gov (United States)

    Huang, H. K.; Cao, Fei; Zhou, Michael Z.; Mogel, Greg T.; Liu, Brent J.; Zhou, Xiaoqiang

    2003-05-01

    Health data security, characterized in terms of data privacy, authenticity, and integrity, is a vital issue when digital images and other patient information are transmitted through public networks in telehealth applications such as teleradiology. Mandates for ensuring health data security have been extensively discussed (for example The Health Insurance Portability and Accountability Act, HIPAA) and health informatics guidelines (such as the DICOM standard) are beginning to focus on issues of data continue to be published by organizing bodies in healthcare; however, there has not been a systematic method developed to ensure data security in medical imaging Because data privacy and authenticity are often managed primarily with firewall and password protection, we have focused our research and development on data integrity. We have developed a systematic method of ensuring medical image data integrity across public networks using the concept of the digital envelope. When a medical image is generated regardless of the modality, three processes are performed: the image signature is obtained, the DICOM image header is encrypted, and a digital envelope is formed by combining the signature and the encrypted header. The envelope is encrypted and embedded in the original image. This assures the security of both the image and the patient ID. The embedded image is encrypted again and transmitted across the network. The reverse process is performed at the receiving site. The result is two digital signatures, one from the original image before transmission, and second from the image after transmission. If the signatures are identical, there has been no alteration of the image. This paper concentrates in the method and evaluation of the digital image envelope.

  12. The cell envelope glycoconjugates of Mycobacterium tuberculosis

    Science.gov (United States)

    Angala, Shiva Kumar; Belardinelli, Juan Manuel; Huc-Claustre, Emilie; Wheat, William H.; Jackson, Mary

    2015-01-01

    Tuberculosis (TB) remains the second most common cause of death due to a single infectious agent. The cell envelope of Mycobacterium tuberculosis (Mtb), the causative agent of the disease in humans, is a source of unique glycoconjugates and the most distinctive feature of the biology of this organism. It is the basis of much of Mtb pathogenesis and one of the major causes of its intrinsic resistance to chemotherapeutic agents. At the same time, the unique structures of Mtb cell envelope glycoconjugates, their antigenicity and essentiality for mycobacterial growth provide opportunities for drug, vaccine, diagnostic and biomarker development, as clearly illustrated by recent advances in all of these translational aspects. This review focuses on our current understanding of the structure and biogenesis of Mtb glycoconjugates with particular emphasis on one of most intriguing and least understood aspect of the physiology of mycobacteria: the translocation of these complex macromolecules across the different layers of the cell envelope. It further reviews the rather impressive progress made in the last ten years in the discovery and development of novel inhibitors targeting their biogenesis. PMID:24915502

  13. Spectral envelope sensitivity of musical instrument sounds.

    Science.gov (United States)

    Gunawan, David; Sen, D

    2008-01-01

    It is well known that the spectral envelope is a perceptually salient attribute in musical instrument timbre perception. While a number of studies have explored discrimination thresholds for changes to the spectral envelope, the question of how sensitivity varies as a function of center frequency and bandwidth for musical instruments has yet to be addressed. In this paper a two-alternative forced-choice experiment was conducted to observe perceptual sensitivity to modifications made on trumpet, clarinet and viola sounds. The experiment involved attenuating 14 frequency bands for each instrument in order to determine discrimination thresholds as a function of center frequency and bandwidth. The results indicate that perceptual sensitivity is governed by the first few harmonics and sensitivity does not improve when extending the bandwidth any higher. However, sensitivity was found to decrease if changes were made only to the higher frequencies and continued to decrease as the distorted bandwidth was widened. The results are analyzed and discussed with respect to two other spectral envelope discrimination studies in the literature as well as what is predicted from a psychoacoustic model.

  14. UNVEILING THE EVOLUTIONARY SEQUENCE FROM INFALLING ENVELOPES TO KEPLERIAN DISKS AROUND LOW-MASS PROTOSTARS

    Energy Technology Data Exchange (ETDEWEB)

    Yen, Hsi-Wei [Institute of Astrophysics, National Taiwan University, Taipei 10617, Taiwan (China); Takakuwa, Shigehisa; Ohashi, Nagayoshi; Ho, Paul T. P., E-mail: hwyen@asiaa.sinica.edu.tw [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)

    2013-07-20

    We performed Submillimeter Array observations in the C{sup 18}O (2-1) emission line toward six Class 0 and I protostars to study rotational motions of their surrounding envelopes and circumstellar material on 100-1000 AU scales. C{sup 18}O (2-1) emission with intensity peaks located at the protostellar positions is detected toward all six sources. The rotational velocities of the protostellar envelopes as a function of radius were measured from the position-velocity diagrams perpendicular to the outflow directions passing through the protostellar positions. Two Class 0 sources, B335 and NGC 1333 IRAS 4B, show no detectable rotational motion, while L1527 IRS (Class 0/I) and L1448-mm (Class 0) exhibit rotational motions with radial profiles of V{sub rot}{proportional_to}r {sup -1.0{+-}0.2} and {proportional_to}r {sup -1.0{+-}0.1}, respectively. The other Class I sources, TMC-1A and L1489 IRS, exhibit the fastest rotational motions among the sample, and their rotational motions have flatter radial profiles of V{sub rot}{proportional_to}r {sup -0.6{+-}0.1} and {proportional_to}r {sup -0.5{+-}0.1}, respectively. The rotational motions with the radial dependence of {approx}r {sup -1} can be interpreted as rotation with a conserved angular momentum in a dynamically infalling envelope, while those with the radial dependence of {approx}r {sup -0.5} can be interpreted as Keplerian rotation. These observational results demonstrate categorization of rotational motions from infalling envelopes to Keplerian-disk formation. Models of the inside-out collapse where the angular momentum is conserved are discussed and compared with our observational results.

  15. Water velocity meter

    Science.gov (United States)

    Roberts, C. W.; Smith, D. L.

    1970-01-01

    Simple, inexpensive drag sphere velocity meter with a zero to 6 ft/sec range measures steady-state flow. When combined with appropriate data acquisition system, it is suited to applications where large numbers of simultaneous measurements are needed for current mapping or velocity profile determination.

  16. Estimation of vector velocity

    DEFF Research Database (Denmark)

    2000-01-01

    Using a pulsed ultrasound field, the two-dimensional velocity vector can be determined with the invention. The method uses a transversally modulated ultrasound field for probing the moving medium under investigation. A modified autocorrelation approach is used in the velocity estimation. The new...

  17. Nonlinear evolutions of an ultra-intense ultra-short laser pulse in a rarefied plasma through a new quasi-static theory

    Science.gov (United States)

    Yazdanpanah, J.

    2018-02-01

    In this paper, we present a new description of self-consistent wake excitation by an intense short laser pulse, based on applying the quasi-static approximation (slow variations of the pulse-envelope) in the instantaneous Lorentz-boosted pulse co-moving frame (PCMF), and best verify our results through comparison with particle-in-cell simulations. According to this theory, the plasma motion can be treated perturbatively in the PCMF due to its high initial-velocity and produces a quasi-static wakefield in this frame. The pulse envelope, on the other hand, is governed by a form of the Schrödinger equation in the PCMF, in which the wakefield acts as an effective potential. In this context, pulse evolutions are characterized by local conservation laws resulted from this equation and subjected to Lorentz transformation into the laboratory frame. Using these conservation laws, precise formulas are obtained for spatiotemporal pulse evolutions and related wakefield variations at initial stages, and new equations are derived for instantaneous group velocity and carrier frequency. In addition, based on properties of the Schrödinger equation, spectral-evolutions of the pulse are described and the emergence of an anomalous dispersion branch with linear relation ω ≈ ck (c is the light speed) is predicted. Our results are carefully discussed versus previous publications and the significance of our approach is described by showing almost all suggestive definitions of group-velocity based on energy arguments fail to reproduce our formula and correctly describe the instantaneous pulse-velocity.

  18. The VLT-FLAMES Tarantula Survey. XII. Rotational velocities of the single O-type stars

    Science.gov (United States)

    Ramírez-Agudelo, O. H.; Simón-Díaz, S.; Sana, H.; de Koter, A.; Sabín-Sanjulían, C.; de Mink, S. E.; Dufton, P. L.; Gräfener, G.; Evans, C. J.; Herrero, A.; Langer, N.; Lennon, D. J.; Maíz Apellániz, J.; Markova, N.; Najarro, F.; Puls, J.; Taylor, W. D.; Vink, J. S.

    2013-12-01

    Context. The 30 Doradus (30 Dor) region of the Large Magellanic Cloud, also known as the Tarantula nebula, is the nearest starburst region. It contains the richest population of massive stars in the Local Group, and it is thus the best possible laboratory to investigate open questions on the formation and evolution of massive stars. Aims: Using ground-based multi-object optical spectroscopy obtained in the framework of the VLT-FLAMES Tarantula Survey (VFTS), we aim to establish the (projected) rotational velocity distribution for a sample of 216 presumably single O-type stars in 30 Dor. The sample is large enough to obtain statistically significant information and to search for variations among subpopulations - in terms of spectral type, luminosity class, and spatial location - in the field of view. Methods: We measured projected rotational velocities, νesini, by means of a Fourier transform method and a profile fitting method applied to a set of isolated spectral lines. We also used an iterative deconvolution procedure to infer the probability density, P(νe), of the equatorial rotational velocity, νe. Results: The distribution of νesini shows a two-component structure: a peak around 80 kms-1 and a high-velocity tail extending up to ~600 kms-1. This structure is also present in the inferred distribution P(νe) with around 80% of the sample having 0 rate less than 20% of their break-up velocity. For the bulk of the sample, mass loss in a stellar wind and/or envelope expansion is not efficient enough to significantly spin down these stars within the first few Myr of evolution. If massive-star formation results in stars rotating at birth with a large portion of their break-up velocities, an alternative braking mechanism, possibly magnetic fields, is thus required to explain the present-day rotational properties of the O-type stars in 30 Dor. The presence of a sizeable population of fast rotators is compatible with recent population synthesis computations that

  19. Magnetic and Velocity Field Variations in the Active Regions NOAA ...

    Indian Academy of Sciences (India)

    Abstract. We study the magnetic and velocity field evolution in the two magnetically complex active regions NOAA 10486 and NOAA 10488 observed during October–November 2003. We have used the available data to examine net flux and Doppler velocity time profiles to identify changes associated with evolutionary and ...

  20. Microclimatic conditions at the external surface of building envelopes

    Energy Technology Data Exchange (ETDEWEB)

    Kragh, M.K.

    1998-12-31

    The project is described, the motivation for the research and the microclimate is defined in relation to both building physics research and applications. Air temperatur, air humidity, solar radiation and air velocity are briefly considered, whilst driving rain and long-wave radiation are described in more detail. Convective heat transfer and surface coefficients are discussed, although they are not microclimatic factors, merely resulting from combinations of such factors. They are included as they are important in relation to transfer of heat and moisture at the surface of the building envelope. Driving rain measurement is the main area of interest, including development of measurement equipment. Long-wave irradiation is measured and compared with empirical formulae from the literature. Window convection heat transfer is another main area of interest. Nocturnal convective heat transfer from a double pane glazing is studied and measurement principles are discussed. Finally, a compilation of meteorological data for hygrothermal simulations, including estimation of driving rain, is described. System error estimation in relation to the window convection measurements, design notes on an apparatus for external convection measurement, formulae for conversion of relative humitity and dry-bulb temperature into dew point temperature. (EG) 66 refs.

  1. Tides in differentially rotating convective envelopes. II. The tidal coupling

    International Nuclear Information System (INIS)

    Scharlemann, E.T.

    1982-01-01

    The tidal coupling between a star with an extended, differentially rotating convective envelope, and its companion in a close binary system, is calculated from the tidal velocity field derived in Paper I. The derived coupling torque can be tested using observations of RS Canum Venaticorum systems, for which a photometric wave in the light curve provides an accurate stellar rotation rate, and for which observed orbital period changes require the stars in the systems to be coupled. The coupling torque is sufficient to explain the nearly synchronous rotation of the active star in RS CVn systems, despite the observed orbital period changes, but may not be able to explain the extreme tightness of the coupling implied by the very long periods for the migration of the photometric waves in the systems. This conclusion depends on the origin of the orbital period changes, but not on the nature of the wave or the wave migration. When the coupling torque vanishes, a specific latitude at the surface of the convective star will exactly corotate with the binary system: this corotation latitude is calculated. Finally, it is shown that the additional viscous terms introduced by tides should not suppress differential rotation in binary systems with RS Cvn parameters

  2. Microclimatic conditions at the external surface of building envelopes

    Energy Technology Data Exchange (ETDEWEB)

    Kragh, M K

    1999-12-31

    The project is described, the motivation for the research and the microclimate is defined in relation to both building physics research and applications. Air temperatur, air humidity, solar radiation and air velocity are briefly considered, whilst driving rain and long-wave radiation are described in more detail. Convective heat transfer and surface coefficients are discussed, although they are not microclimatic factors, merely resulting from combinations of such factors. They are included as they are important in relation to transfer of heat and moisture at the surface of the building envelope. Driving rain measurement is the main area of interest, including development of measurement equipment. Long-wave irradiation is measured and compared with empirical formulae from the literature. Window convection heat transfer is another main area of interest. Nocturnal convective heat transfer from a double pane glazing is studied and measurement principles are discussed. Finally, a compilation of meteorological data for hygrothermal simulations, including estimation of driving rain, is described. System error estimation in relation to the window convection measurements, design notes on an apparatus for external convection measurement, formulae for conversion of relative humitity and dry-bulb temperature into dew point temperature. (EG) 66 refs.

  3. Shape Control of Responsive Building Envelopes

    DEFF Research Database (Denmark)

    Foged, Isak Worre; Kirkegaard, Poul Henning; Christensen, Jesper Thøger

    2010-01-01

    The present paper considers shape control of adaptive architectural structures for improvement of structural performance by recognizing changes in their environments and loads, adapting to meet goals, and using past events to improve future performance or maintain serviceability. The general scop...... environmental system to a primary structural system joint into a collective behavioral system equipment with an actuator system is presented....... alternatives. The adaptive structure is a proposal for a responsive building envelope which is an idea of a first level operational framework for present and future investigations towards performance based responsive architectures through a set of responsive typologies. A mock-up concept of a secondary...

  4. Snell Envelope with Small Probability Criteria

    Energy Technology Data Exchange (ETDEWEB)

    Del Moral, Pierre, E-mail: Pierre.Del-Moral@inria.fr; Hu, Peng, E-mail: Peng.Hu@inria.fr [Universite de Bordeaux I, Centre INRIA Bordeaux et Sud-Ouest and Institut de Mathematiques de Bordeaux (France); Oudjane, Nadia, E-mail: Nadia.Oudjane@edf.fr [EDF R and D Clamart (France)

    2012-12-15

    We present a new algorithm to compute the Snell envelope in the specific case where the criteria to optimize is associated with a small probability or a rare event. This new approach combines the Stochastic Mesh approach of Broadie and Glasserman with a particle approximation scheme based on a specific change of measure designed to concentrate the computational effort in regions pointed out by the criteria. The theoretical analysis of this new algorithm provides non asymptotic convergence estimates. Finally, the numerical tests confirm the practical interest of this approach.

  5. GEOMETRIC AND KINEMATIC STRUCTURE OF THE OUTFLOW/ENVELOPE SYSTEM OF L1527 REVEALED BY SUBARCSECOND-RESOLUTION OBSERVATION OF CS

    Energy Technology Data Exchange (ETDEWEB)

    Oya, Yoko; López-Sepulcre, Ana; Watanabe, Yoshimasa; Yamamoto, Satoshi [Department of Physics, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Sakai, Nami [The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198 (Japan); Lefloch, Bertrand; Ceccarelli, Cecilia, E-mail: oya@taurus.phys.s.u-tokyo.ac.jp [Universite Grenoble Alpes, IPAG, F-38000 Grenoble (France)

    2015-10-10

    Subarcsecond-resolution images of the rotational line emissions of CS and c-C{sub 3}H{sub 2} obtained toward the low-mass protostar IRAS 04368+2557 in L1527 with the Atacama Large Millimeter/submillimeter Array are investigated to constrain the orientation of the outflow/envelope system. The distribution of CS consists of an envelope component extending from north to south and a faint butterfly shaped outflow component. The kinematic structure of the envelope is well reproduced by a simple ballistic model of an infalling rotating envelope. Although the envelope has a nearly edge-on configuration, we find that the western side of the envelope faces the observer. This configuration is opposite to the direction of the large-scale (∼10{sup 4} AU) outflow suggested previously from the {sup 12}CO (J = 3–2) observation, and to the morphology of infrared reflection near the protostar (∼200 AU). The latter discrepancy could originate from high extinction by the outflow cavity of the western side, or may indicate that the outflow axis is not parallel to the rotation axis of the envelope. Position–velocity diagrams show the accelerated outflow cavity wall, and its kinematic structure in the 2000 AU scale is explained by a standard parabolic model with the inclination angle derived from the analysis of the envelope. The different orientation of the outflow between the small and large scale implies a possibility of precession of the outflow axis. The shape and the velocity of the outflow in the vicinity of the protostar are compared with those of other protostars.

  6. Envelope as Climate Negotiator: Evaluating adaptive building envelope's capacity to moderate indoor climate and energy

    Science.gov (United States)

    Erickson, James

    Through manipulation of adaptable opportunities available within a given environment, individuals become active participants in managing personal comfort requirements, by exercising control over their comfort without the assistance of mechanical heating and cooling systems. Similarly, continuous manipulation of a building skin's form, insulation, porosity, and transmissivity qualities exerts control over the energy exchanged between indoor and outdoor environments. This research uses four adaptive response variables in a modified software algorithm to explore an adaptive building skin's potential in reacting to environmental stimuli with the purpose of minimizing energy use without sacrificing occupant comfort. Results illustrate that significant energy savings can be realized with adaptive envelopes over static building envelopes even under extreme summer and winter climate conditions; that the magnitude of these savings are dependent on climate and orientation; and that occupant thermal comfort can be improved consistently over comfort levels achieved by optimized static building envelopes. The resulting adaptive envelope's unique climate-specific behavior could inform designers in creating an intelligent kinetic aesthetic that helps facilitate adaptability and resiliency in architecture.

  7. THE STELLAR VELOCITY DISPERSION OF A COMPACT MASSIVE GALAXY AT z = 1.80 USING X-SHOOTER: CONFIRMATION OF THE EVOLUTION IN THE MASS-SIZE AND MASS-DISPERSION RELATIONS ,

    International Nuclear Information System (INIS)

    Van de Sande, Jesse; Franx, Marijn; Labbe, Ivo; Kriek, Mariska; Van Dokkum, Pieter G.; Bezanson, Rachel; Whitaker, Katherine E.; Brammer, Gabriel; Groot, Paul J.; Kaper, Lex

    2011-01-01

    Recent photometric studies have shown that early-type galaxies at fixed stellar mass were smaller and denser at earlier times. In this Letter, we assess that finding by deriving the dynamical mass of such a compact quiescent galaxy at z = 1.8. We have obtained a high-quality spectrum with full UV-NIR wavelength coverage of galaxy NMBS-C7447 using X-Shooter on the Very Large Telescope. We determined a velocity dispersion of 294 ± 51 km s -1 . Given this velocity dispersion and the effective radius of 1.64 ± 0.15 kpc (as determined from Hubble Space Telescope Wide Field Camera 3 F160W observations) we derive a dynamical mass of (1.7 ± 0.5) x 10 11 M sun . Comparison of the full spectrum with stellar population synthesis models indicates that NMBS-C774 has a relatively young stellar population (0.40 Gyr) with little or no star formation and a stellar mass of M * ∼ 1.5 x 10 11 M sun . The dynamical and photometric stellar masses are in good agreement. Thus, our study supports the conclusion that the mass densities of quiescent galaxies were indeed higher at earlier times, and this earlier result is not caused by systematic measurement errors. By combining available spectroscopic measurements at different redshifts, we find that the velocity dispersion at fixed dynamical mass was a factor of ∼1.8 higher at z = 1.8 compared with z = 0. Finally, we show that the apparent discrepancies between the few available velocity dispersion measurements at z > 1.5 are consistent with the intrinsic scatter of the mass-size relation.

  8. MAGNETIZATION OF CLOUD CORES AND ENVELOPES AND OTHER OBSERVATIONAL CONSEQUENCES OF RECONNECTION DIFFUSION

    International Nuclear Information System (INIS)

    Lazarian, A.; Esquivel, A.; Crutcher, R.

    2012-01-01

    Recent observational results for magnetic fields in molecular clouds reviewed by Crutcher seem to be inconsistent with the predictions of the ambipolar diffusion theory of star formation. These include the measured decrease in mass to flux ratio between envelopes and cores, the failure to detect any self-gravitating magnetically subcritical clouds, the determination of the flat probability distribution function (PDF) of the total magnetic field strengths implying that there are many clouds with very weak magnetic fields, and the observed scaling B∝ρ 2/3 that implies gravitational contraction with weak magnetic fields. We consider the problem of magnetic field evolution in turbulent molecular clouds and discuss the process of magnetic field diffusion mediated by magnetic reconnection. For this process that we termed 'reconnection diffusion', we provide a simple physical model and explain that this process is inevitable in view of the present-day understanding of MHD turbulence. We address the issue of the expected magnetization of cores and envelopes in the process of star formation and show that reconnection diffusion provides an efficient removal of magnetic flux that depends only on the properties of MHD turbulence in the core and the envelope. We show that as the amplitude of turbulence as well as the scale of turbulent motions decrease from the envelope to the core of the cloud, the diffusion of the magnetic field is faster in the envelope. As a result, the magnetic flux trapped during the collapse in the envelope is being released faster than the flux trapped in the core, resulting in much weaker fields in envelopes than in cores, as observed. We provide simple semi-analytical model calculations which support this conclusion and qualitatively agree with the observational results. Magnetic reconnection is also consistent with the lack of subcritical self-gravitating clouds, with the observed flat PDF of field strengths, and with the scaling of field strength

  9. MAGNETIZATION OF CLOUD CORES AND ENVELOPES AND OTHER OBSERVATIONAL CONSEQUENCES OF RECONNECTION DIFFUSION

    Energy Technology Data Exchange (ETDEWEB)

    Lazarian, A. [Astronomy Department, University of Wisconsin, Madison, WI 53706 (United States); Esquivel, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, 04510 Mexico D.F. (Mexico); Crutcher, R. [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801 (United States)

    2012-10-01

    Recent observational results for magnetic fields in molecular clouds reviewed by Crutcher seem to be inconsistent with the predictions of the ambipolar diffusion theory of star formation. These include the measured decrease in mass to flux ratio between envelopes and cores, the failure to detect any self-gravitating magnetically subcritical clouds, the determination of the flat probability distribution function (PDF) of the total magnetic field strengths implying that there are many clouds with very weak magnetic fields, and the observed scaling B{proportional_to}{rho}{sup 2/3} that implies gravitational contraction with weak magnetic fields. We consider the problem of magnetic field evolution in turbulent molecular clouds and discuss the process of magnetic field diffusion mediated by magnetic reconnection. For this process that we termed 'reconnection diffusion', we provide a simple physical model and explain that this process is inevitable in view of the present-day understanding of MHD turbulence. We address the issue of the expected magnetization of cores and envelopes in the process of star formation and show that reconnection diffusion provides an efficient removal of magnetic flux that depends only on the properties of MHD turbulence in the core and the envelope. We show that as the amplitude of turbulence as well as the scale of turbulent motions decrease from the envelope to the core of the cloud, the diffusion of the magnetic field is faster in the envelope. As a result, the magnetic flux trapped during the collapse in the envelope is being released faster than the flux trapped in the core, resulting in much weaker fields in envelopes than in cores, as observed. We provide simple semi-analytical model calculations which support this conclusion and qualitatively agree with the observational results. Magnetic reconnection is also consistent with the lack of subcritical self-gravitating clouds, with the observed flat PDF of field strengths, and

  10. The performance of energy efficient residential building envelope systems

    Energy Technology Data Exchange (ETDEWEB)

    Proskiw, G.

    1996-08-01

    The adequacy and durability of residential building envelope systems under actual field conditions were evaluated. A building envelope offers protection from cold, heat, moisture, wind and noise. However, they are exposed to thermal, structural, and moisture stresses and their performance can degrade over time. Envelope performance was evaluated at 20 energy efficient and four conventional, detached modern homes in Winnipeg, Canada. The three complementary measurement tools were wood moisture content (WMC) of framing members, thermographic examinations, and airtightness tests. As expected, energy efficient building envelope systems performed better than the conventional systems. No evidence of envelope degradation was found in any of the energy efficient houses. The building envelopes using polyethylene air barriers performed slightly better than those which used the airtight drywall approach, although both were considered satisfactory. WMC levels were a bit lower in the polyethylene-clad house. 1 ref., 1 tab.

  11. Velocity Feedback Experiments

    Directory of Open Access Journals (Sweden)

    Chiu Choi

    2017-02-01

    Full Text Available Transient response such as ringing in a control system can be reduced or removed by velocity feedback. It is a useful control technique that should be covered in the relevant engineering laboratory courses. We developed velocity feedback experiments using two different low cost technologies, viz., operational amplifiers and microcontrollers. These experiments can be easily integrated into laboratory courses on feedback control systems or microcontroller applications. The intent of developing these experiments was to illustrate the ringing problem and to offer effective, low cost solutions for removing such problem. In this paper the pedagogical approach for these velocity feedback experiments was described. The advantages and disadvantages of the two different implementation of velocity feedback were discussed also.

  12. The critical ionization velocity

    International Nuclear Information System (INIS)

    Raadu, M.A.

    1980-06-01

    The critical ionization velocity effect was first proposed in the context of space plasmas. This effect occurs for a neutral gas moving through a magnetized plasma and leads to rapid ionization and braking of the relative motion when a marginal velocity, 'the critical velocity', is exceeded. Laboratory experiments have clearly established the significance of the critical velocity and have provided evidence for an underlying mechanism which relies on the combined action of electron impact ionization and a collective plasma interaction heating electrons. There is experimental support for such a mechanism based on the heating of electrons by the modified two-stream instability as part of a feedback process. Several applications to space plasmas have been proposed and the possibility of space experiments has been discussed. (author)

  13. High Velocity Gas Gun

    Science.gov (United States)

    1988-01-01

    A video tape related to orbital debris research is presented. The video tape covers the process of loading a High Velocity Gas Gun and firing it into a mounted metal plate. The process is then repeated in slow motion.

  14. Grain formation in cool stellar envelopes

    International Nuclear Information System (INIS)

    Deguchi, S.

    1980-01-01

    The nucleation and growth of dust grains in the stellar envelope are investigated for the case of oxygen-rich stars, where the mass loss occurs as a result of the radiation pressure on the dust grains. The number density of grains, the final grain sizes, and the final amount of metals remaining in gaseous states are calculated based on the grain-nucleation theory proposed by Yamamoto and Hasegawa and Draine and Salpeter. It is shown that, even if we base our calculations on the Lothe-Pound nucleation rate equation instead of the classical, homogeneous nucleation rate equation, the proposed theory gives a number density of grains quite similar to that based on the classical rate equation. The approximate solution of the flow, in this paper, brings physical insight to the problem of how the formation of grains couples the flow passing the sonic point. The metals in the outer envelope remain in gaseous state by the amount of 1--10% of the initial content for the mass-loss rate of 10 -5 M/sub sun/ yr -1 and by less than 1% for the massloss are less than 3 x 10 -6 M/sub sun/ yr -1 . Species of metals condensed onto the grains are also discussed

  15. Bellanca building, Yellowknife : building envelope retrofit project

    Energy Technology Data Exchange (ETDEWEB)

    Rajewski, G. [A.D. Williams Engineering Inc., Edmonton, AB (Canada)

    2008-07-01

    The Bellanca building is a ten-story, commercial office building, located in Yellowknife, Northwest Territories. The owner was concerned about annual fuel consumption, relative to other buildings of similar size. Tenants reported cold drafts and some ice build-up had been reported in the past, on the exterior of the cladding. In addition, some water penetration had occurred during rainfall. This presentation provided background information on the Bellanca building and discussed a building envelope retrofit project. A.D. Williams was hired in late 2006 in order to provide an opinion on the present condition of the building envelope. This presentation described the site investigation and presented an interior and exterior review of the building. It also presented a thermographic survey in order to map thermal anomalies and establish trends. Following acceptance of the report on findings, one of five options was selected for further development. This included removal of existing cladding, exterior gypsum wallboard, fiberglass insulation and application of BASF Walltite CT foam, sheathing, rigid insulation, drainage plane and new cladding. The preliminary design was then presented. This paper also described the tender and award of the contract; construction phase; and substantial completion of the project. tabs, figs.

  16. Chemistry of Protostellar Envelopes and Disks

    Science.gov (United States)

    Flores Rivera, Lizxandra; Terebey, Susan; Willacy, Karen

    2018-06-01

    Molecule formation is dynamic during the protostar collapse phase, driven by changes in temperature, density, and UV radiation as gas and dust flows from the envelope onto the forming protoplanetary disk. In this work, we compare physical models based on two different collapse solutions. We modeled the chemistry (created by Karen Willacy) for C18O to see how its abundance changes over time using as primary input parameters the temperature and density profile that were produced by the dust Radiative Transfer (MCRT) model called HOCHUNK3D from Whitney (2003). Given this model, we produce synthetic line emission maps from L1527 IRS to simulate the Class 0/I protostar L1527 IRS using RADMC3D code and compare them with previous observations from ALMA. High concentrations of gas phase molecules of C18O are found within the 20 AU in areas in the envelope that are close to the surface of the disk. In the outermost part of the disk surface, the C18O freezes out beyond 400 AU, showing a much reduced abundance where the temperature profile drops down below 25 K. In cold regions, the radiation field plays an important role in the chemistry.

  17. [An improved algorithm for electrohysterogram envelope extraction].

    Science.gov (United States)

    Lu, Yaosheng; Pan, Jie; Chen, Zhaoxia; Chen, Zhaoxia

    2017-02-01

    Extraction uterine contraction signal from abdominal uterine electromyogram(EMG) signal is considered as the most promising method to replace the traditional tocodynamometer(TOCO) for detecting uterine contractions activity. The traditional root mean square(RMS) algorithm has only some limited values in canceling the impulsive noise. In our study, an improved algorithm for uterine EMG envelope extraction was proposed to overcome the problem. Firstly, in our experiment, zero-crossing detection method was used to separate the burst of uterine electrical activity from the raw uterine EMG signal. After processing the separated signals by employing two filtering windows which have different width, we used the traditional RMS algorithm to extract uterus EMG envelope. To assess the performance of the algorithm, the improved algorithm was compared with two existing intensity of uterine electromyogram(IEMG) extraction algorithms. The results showed that the improved algorithm was better than the traditional ones in eliminating impulsive noise present in the uterine EMG signal. The measurement sensitivity and positive predictive value(PPV) of the improved algorithm were 0.952 and 0.922, respectively, which were not only significantly higher than the corresponding values(0.859 and 0.847) of the first comparison algorithm, but also higher than the values(0.928 and 0.877) of the second comparison algorithm. Thus the new method is reliable and effective.

  18. Solution of K-V envelope equations

    International Nuclear Information System (INIS)

    Anderson, O.A.

    1995-04-01

    The envelope equations for a KV beam with space charge have been analyzed systematically by an e expansion followed by integrations. The focusing profile as a function of axial length is assumed to be symmetric but otherwise arbitrary. Given the bean current, emittance, and peak focusing field, we find the envelopes a(s) and b(s) and obtain , a max , σ, and σ 0 . Explicit results are presented for various truncations of the expansion. The zeroth order results correspond to those from the well-known smooth approximation; the same convenient format is retained for the higher order cases. The first order results, involving single correction terms, give 3--10 times better accuracy and are good to ∼1% at σ 0 = 70 degree. Third order gives a factor of 10--30 improvement over the smooth approximation and derived quantities accurate to ∼1% at σ 0 = 112 degree. The first order expressions are convenient design tools. They lend themselves to variable energy problems and have been applied to the design, construction, and testing of ESQ accelerators at LBL

  19. POET: Planetary Orbital Evolution due to Tides

    Science.gov (United States)

    Penev, Kaloyan

    2014-08-01

    POET (Planetary Orbital Evolution due to Tides) calculates the orbital evolution of a system consisting of a single star with a single planet in orbit under the influence of tides. The following effects are The evolutions of the semimajor axis of the orbit due to the tidal dissipation in the star and the angular momentum of the stellar convective envelope by the tidal coupling are taken into account. In addition, the evolution includes the transfer of angular momentum between the stellar convective and radiative zones, effect of the stellar evolution on the tidal dissipation efficiency, and stellar core and envelope spins and loss of stellar convective zone angular momentum to a magnetically launched wind. POET can be used out of the box, and can also be extended and modified.

  20. Mechanism of protein import across the chloroplast envelope.

    Science.gov (United States)

    Chen, K; Chen, X; Schnell, D J

    2000-01-01

    The development and maintenance of chloroplasts relies on the contribution of protein subunits from both plastid and nuclear genomes. Most chloroplast proteins are encoded by nuclear genes and are post-translationally imported into the organelle across the double membrane of the chloroplast envelope. Protein import into the chloroplast consists of two essential elements: the specific recognition of the targeting signals (transit sequences) of cytoplasmic preproteins by receptors at the outer envelope membrane and the subsequent translocation of preproteins simultaneously across the double membrane of the envelope. These processes are mediated via the co-ordinate action of protein translocon complexes in the outer (Toc apparatus) and inner (Tic apparatus) envelope membranes.

  1. Adaptive Flight Envelope Estimation and Protection, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Impact Technologies, in collaboration with the Georgia Institute of Technology, proposes to develop and demonstrate an innovative flight envelope estimation and...

  2. Extremely Low Mass: The Circumstellar Envelope of a Potential Proto-Brown Dwarf

    Science.gov (United States)

    Wiseman, Jennifer

    2011-01-01

    What is the environment for planet formation around extremely low mass stars? Is the environment around brown dwarfs and extremely low mass stars conducive and sufficiently massive for planet production? The determining conditions may be set very early in the process of the host object's formation. IRAS 16253-2429, the source of the Wasp-Waist Nebula seen in Spitzer IRAC images, is an isolated, very low luminosity ("VeLLO") Class 0 protostar in the nearby rho Ophiuchi cloud. We present VLA ammonia mapping observations of the dense gas envelope feeding the central core accreting system. We find a flattened envelope perpendicular to the outflow axis, and gas cavities that appear to cradle the outflow lobes as though carved out by the flow and associated (apparently precessing) jet, indicating environmental disruption. Based on the NH3 (1,1) and (2,2) emission distribution, we derive the mass, velocity fields and temperature distribution for the envelope. We discuss the combined evidence for this source to be one of the youngest and lowest mass sources in formation yet known, and discuss the ramifications for planet formation potential in this extremely low mass system.

  3. On protostellar evolution

    International Nuclear Information System (INIS)

    Westbrook, C.K.; Tarter, C.B.

    1975-01-01

    An investigation of the evolution of spherically symmetric protostars with initial masses in the range 0.1less than or equal toM/M/sub sun/less than or equal to50 has been carried out. In order to perform the calculations, a numerical technique has been developed in which rapid dynamical motions in one region of the star and quasi-static evolution in another region can be simultaneously computed. The general evolutionary features are similar to those found by other workers: an initial free-fall collapse is followed by the creation of a core in hydrostatic equilibrium, and the core's subsequent accretion of the surrounding envelope. However, our final hydrostatic-equilibrium configurations have radii large compared with those of the protostellar models of Larson (but in reasonable agreement with those of conventional pre-main-sequence models). For low-mass protostars (Mless than or equal toM/sub sun/) the luminosity remains relatively small until late evolutionary times and the evolution is very sensitive to the treatment of convective energy transport. For large-mass protostars (Mgreater than or equal to3M/sub sun/) a convective phase never exists, and a fraction (increasing with mass) of the initial mass is ejected by the combined effects of heating and radiation pressure in the envelope

  4. ALMA Observations of the Water Fountain Pre-Planetary Nebula IRAS 16342-3814: High-Velocity Bipolar Jets and an Expanding Torus.

    Science.gov (United States)

    Sahai, R; Vlemmings, W H T; Gledhill, T; Sánchez Contreras, C; Lagadec, E; Nyman, L-Å; Quintana-Lacaci, G

    2017-01-20

    We have mapped 12 CO J=3-2 and other molecular lines from the "water-fountain" bipolar pre-planetary nebula (PPN) IRAS 16342-3814 with [Formula: see text] resolution using ALMA. We find (i) two very high-speed knotty, jet-like molecular outflows, (ii) a central high-density (> few × 10 6 cm -3 ), expanding torus of diameter 1300 AU, and (iii) the circumstellar envelope of the progenitor AGB, generated by a sudden, very large increase in the mass-loss rate to > 3.5 × 10 -4 M ⊙ yr -1 in the past ~455 yr. Strong continuum emission at 0.89 mm from a central source (690 mJy), if due to thermally-emitting dust, implies a substantial mass (0.017 M ⊙ ) of very large (~mm-sized) grains. The measured expansion ages of the above structural components imply that the torus (age~160 yr) and the younger high-velocity outflow (age~110 yr) were formed soon after the sharp increase in the AGB mass-loss rate. Assuming a binary model for the jets in IRAS 16342, the high momentum rate for the dominant jet-outflow in IRAS 16342 implies a high minimum accretion rate, ruling out standard Bondi-Hoyle-Lyttleton wind accretion and wind Roche lobe overflow (RLOF) models with white-dwarf or main-sequence companions. Most likely, enhanced RLOF from the primary or accretion modes operating within common envelope evolution are needed.

  5. Radiative transfer in spherical circumstellar dust envelopes. III. Dust envelope models of some well known infrared stars

    International Nuclear Information System (INIS)

    Apruzese, J.P.

    1975-01-01

    The radiative transfer techniques described elsewhere by the author have been employed to construct dust envelope models of several well known infrared stars. The resulting calculations indicate that the infrared emissivity of circumstellar grains generally must be higher than that which many calculations of small nonsilicate grains yield. This conclusion is dependent to some degree on the (unknown) size of the stellar envelopes considered, but is quite firm in the case of the spatially resolved envelope of IRC+10216. Further observations of the spatial distribution of the infrared radiation from stellar envelopes will be invaluable in deciphering the properties of the circumstellar grains

  6. Polarimetry and physics of Be star envelopes

    International Nuclear Information System (INIS)

    Coyne, G.V.; McLean, I.S.

    1982-01-01

    A review of the most recent developments in polarization studies of Be stars is presented. New polarization techniques for high-resolution spectropolarimetry and for near infrared polarimetry are described and a wide range of new observations are discussed. These include broad-band, intermediate-band and multichannel observations of the continuum polarization of Be stars in the wavelength interval 0.3-2.2 microns, high resolution (0.5 A) line profile polarimetry of a few stars and surveys of many stars for the purposes of statistical analyses. The physical significance of the observational material is discussed in the light of recent theoretical models. Emphasis is placed on the physical and geometrical parameters of Be star envelopes which polarimetry helps to determine. (Auth.)

  7. Enveloping branes and brane-world singularities

    Energy Technology Data Exchange (ETDEWEB)

    Antoniadis, Ignatios; Cotsakis, Spiros [CERN-Theory Division, Department of Physics, Geneva 23 (Switzerland); Klaoudatou, Ifigeneia [University of the Aegean, Research Group of Geometry, Dynamical Systems and Cosmology, Department of Information and Communication Systems Engineering, Samos (Greece)

    2014-12-01

    The existence of envelopes is studied for systems of differential equations in connection with the method of asymptotic splittings which allows one to determine the singularity structure of the solutions. The result is applied to brane-worlds consisting of a 3-brane in a five-dimensional bulk, in the presence of an analog of a bulk perfect fluid parameterizing a generic class of bulk matter. We find that all flat brane solutions suffer from a finite-distance singularity contrary to previous claims. We then study the possibility of avoiding finite-distance singularities by cutting the bulk and gluing regular solutions at the position of the brane. Further imposing physical conditions such as finite Planck mass on the brane and positive energy conditions on the bulk fluid, excludes, however, this possibility as well. (orig.)

  8. Performance measurement with fuzzy data envelopment analysis

    CERN Document Server

    Tavana, Madjid

    2014-01-01

    The intensity of global competition and ever-increasing economic uncertainties has led organizations to search for more efficient and effective ways to manage their business operations.  Data envelopment analysis (DEA) has been widely used as a conceptually simple yet powerful tool for evaluating organizational productivity and performance. Fuzzy DEA (FDEA) is a promising extension of the conventional DEA proposed for dealing with imprecise and ambiguous data in performance measurement problems. This book is the first volume in the literature to present the state-of-the-art developments and applications of FDEA. It is designed for students, educators, researchers, consultants and practicing managers in business, industry, and government with a basic understanding of the DEA and fuzzy logic concepts.

  9. Data envelopment analysis of randomized ranks

    Directory of Open Access Journals (Sweden)

    Sant'Anna Annibal P.

    2002-01-01

    Full Text Available Probabilities and odds, derived from vectors of ranks, are here compared as measures of efficiency of decision-making units (DMUs. These measures are computed with the goal of providing preliminary information before starting a Data Envelopment Analysis (DEA or the application of any other evaluation or composition of preferences methodology. Preferences, quality and productivity evaluations are usually measured with errors or subject to influence of other random disturbances. Reducing evaluations to ranks and treating the ranks as estimates of location parameters of random variables, we are able to compute the probability of each DMU being classified as the best according to the consumption of each input and the production of each output. Employing the probabilities of being the best as efficiency measures, we stretch distances between the most efficient units. We combine these partial probabilities in a global efficiency score determined in terms of proximity to the efficiency frontier.

  10. Enhanced conformational sampling using enveloping distribution sampling.

    Science.gov (United States)

    Lin, Zhixiong; van Gunsteren, Wilfred F

    2013-10-14

    To lessen the problem of insufficient conformational sampling in biomolecular simulations is still a major challenge in computational biochemistry. In this article, an application of the method of enveloping distribution sampling (EDS) is proposed that addresses this challenge and its sampling efficiency is demonstrated in simulations of a hexa-β-peptide whose conformational equilibrium encompasses two different helical folds, i.e., a right-handed 2.7(10∕12)-helix and a left-handed 3(14)-helix, separated by a high energy barrier. Standard MD simulations of this peptide using the GROMOS 53A6 force field did not reach convergence of the free enthalpy difference between the two helices even after 500 ns of simulation time. The use of soft-core non-bonded interactions in the centre of the peptide did enhance the number of transitions between the helices, but at the same time led to neglect of relevant helical configurations. In the simulations of a two-state EDS reference Hamiltonian that envelops both the physical peptide and the soft-core peptide, sampling of the conformational space of the physical peptide ensures that physically relevant conformations can be visited, and sampling of the conformational space of the soft-core peptide helps to enhance the transitions between the two helices. The EDS simulations sampled many more transitions between the two helices and showed much faster convergence of the relative free enthalpy of the two helices compared with the standard MD simulations with only a slightly larger computational effort to determine optimized EDS parameters. Combined with various methods to smoothen the potential energy surface, the proposed EDS application will be a powerful technique to enhance the sampling efficiency in biomolecular simulations.

  11. Modified circular velocity law

    Science.gov (United States)

    Djeghloul, Nazim

    2018-05-01

    A modified circular velocity law is presented for a test body orbiting around a spherically symmetric mass. This law exhibits a distance scale parameter and allows to recover both usual Newtonian behaviour for lower distances and a constant velocity limit at large scale. Application to the Galaxy predicts the known behaviour and also leads to a galactic mass in accordance with the measured visible stellar mass so that additional dark matter inside the Galaxy can be avoided. It is also shown that this circular velocity law can be embedded in a geometrical description of spacetime within the standard general relativity framework upon relaxing the usual asymptotic flatness condition. This formulation allows to redefine the introduced Newtonian scale limit in term of the central mass exclusively. Moreover, a satisfactory answer to the galactic escape speed problem can be provided indicating the possibility that one can also get rid of dark matter halo outside the Galaxy.

  12. Semiparametric Power Envelopes for Tests of the Unit Root Hypothesis

    DEFF Research Database (Denmark)

    Jansson, Michael

    This paper derives asymptotic power envelopes for tests of the unit root hypothesis in a zero-mean AR(1) model. The power envelopes are derived using the limits of experiments approach and are semiparametric in the sense that the underlying error distribution is treated as an unknown...

  13. Calculation of CWKB envelope in boson and fermion productions

    Indian Academy of Sciences (India)

    Abstract. We present the calculation of envelope of boson and of both low- and high- mass fermion production at the end of inflation when the coherently oscillating inflatons decay into bosons and fermions. We consider three different models of inflation and use. CWKB technique to calculate the envelope to understand the ...

  14. 14 CFR 29.1517 - Limiting height-speed envelope.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limiting height-speed envelope. 29.1517... Operating Limitations § 29.1517 Limiting height-speed envelope. For Category A rotorcraft, if a range of... following power failure, the range of heights and its variation with forward speed must be established...

  15. Beam envelope profile of non-centrosymmetric polygonal phase space

    International Nuclear Information System (INIS)

    Chen Yinbao; Xie Xi

    1984-01-01

    The general theory of beam envelope profile of non-centrosymmetric polygonal phase space is developed. By means of this theory the beam envelope profile of non-centrosymmetric polygonal phase space can be calculated directly. An example is carried out in detail to show the practical application of the theory

  16. Comparison of Fe and Ni opacity calculations for a better understanding of pulsating stellar envelopes

    International Nuclear Information System (INIS)

    Gilles, D.; Turck-Chieze, S.; Loisel, G.; Piau, L.; Ducret, J.E.; Poirier, M.; Blenski, T.; Thais, F.; Blancard, C.; Cosse, P.; Faussurier, G.; Gilleron, F.; Pain, J.C.; Porcherot, Q.; Guzik, J.A.; Kilcrease, D.P.; Magee, N.H.; Harris, J.; Busquet, M.; Delahaye, F.; Zeippen, C.J.; Bastiani-Ceccotti, S.

    2011-01-01

    Opacity is an important ingredient of the evolution of stars. The calculation of opacity coefficients is complicated by the fact that the plasma contains partially ionized heavy ions that contribute to opacity dominated by H and He. Up to now, the astrophysical community has greatly benefited from the work of the contributions of Los Alamos, Livermore and the Opacity Project (OP). However unexplained differences of up to 50% in the radiative forces and Rosseland mean values for Fe have been noticed for conditions corresponding to stellar envelopes. Such uncertainty has a real impact on the understanding of pulsating stellar envelopes, on the excitation of modes, and on the identification of the mode frequencies. Temperature and density conditions equivalent to those found in stars can now be produced in laboratory experiments for various atomic species. Recently the photo-absorption spectra of nickel and iron plasmas have been measured during the LULI 2010 campaign, for temperatures between 15 and 40 eV and densities of similar to 3 mg/cm 3 . A large theoretical collaboration, the 'OPAC', has been formed to prepare these experiments. We present here the set of opacity calculations performed by eight different groups for conditions relevant to the LULI 2010 experiment and to astrophysical stellar envelope conditions. (authors)

  17. A Spectral Algorithm for Envelope Reduction of Sparse Matrices

    Science.gov (United States)

    Barnard, Stephen T.; Pothen, Alex; Simon, Horst D.

    1993-01-01

    The problem of reordering a sparse symmetric matrix to reduce its envelope size is considered. A new spectral algorithm for computing an envelope-reducing reordering is obtained by associating a Laplacian matrix with the given matrix and then sorting the components of a specified eigenvector of the Laplacian. This Laplacian eigenvector solves a continuous relaxation of a discrete problem related to envelope minimization called the minimum 2-sum problem. The permutation vector computed by the spectral algorithm is a closest permutation vector to the specified Laplacian eigenvector. Numerical results show that the new reordering algorithm usually computes smaller envelope sizes than those obtained from the current standard algorithms such as Gibbs-Poole-Stockmeyer (GPS) or SPARSPAK reverse Cuthill-McKee (RCM), in some cases reducing the envelope by more than a factor of two.

  18. The Prescribed Velocity Method

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm

    The- velocity level in a room ventilated by jet ventilation is strongly influenced by the supply conditions. The momentum flow in the supply jets controls the air movement in the room and, therefore, it is very important that the inlet conditions and the numerical method can generate a satisfactory...

  19. Multidisc neutron velocity selector

    International Nuclear Information System (INIS)

    Rosta, L.; Zsigmond, Gy.; Farago, B.; Mezei, F.; Ban, K.; Perendi, J.

    1987-12-01

    The prototype of a velocity selector for neutron monochromatization in the 4-20 A wavelength range is presented. The theoretical background of the multidisc rotor system is given together with a description of the mechanical construction and electronic driving system. The first tests and neutron measurements prove easy handling and excellent parameters. (author) 6 refs.; 7 figs.; 2 tabs

  20. Visualising Three Dimensional Damage and Failure Envelopes: Implications for True Triaxial Deformation

    Science.gov (United States)

    Harland, S. R.; Browning, J.; Healy, D.; Meredith, P. G.; Mitchell, T. M.

    2017-12-01

    Ultimate failure in brittle rocks is commonly accepted to occur as a coalescence of micro-crack damage into a single failure plane. The geometry and evolution with stress of the cracks (damage) within the medium will play a role in dictating the geometry of the ultimate failure plane. Currently, the majority of experimental studies investigating damage evolution and rock failure use conventional triaxial stress states (σ1 > σ2 = σ3). Results from these tests can easily be represented on a Mohr-Coulomb plot (σn - τ), conveniently allowing the user to determine the geometry of the resultant failure plane. In reality however, stress in the subsurface is generally truly triaxial (σ1 > σ2 > σ3) and in this case, the Mohr-Coulomb failure criterion is inadequate as it incorporates no dependence on the intermediate stress (σ2), which has been shown to play an important role in controlling failure. It has recently been shown that differential stress is the key driver in initiating crack growth, regardless of the mean stress. Polyaxial failure criteria that incorporate the effect of the intermediate stress do exist and include the Modified Lade, Modified Wiebols and Cook, and the Drucker-Prager criteria. However, unlike the Mohr-Coulomb failure criterion, these polyaxial criteria do not offer any prediction of, or insight into, the geometry of the resultant failure plane. An additional downfall of all of the common conventional and polyaxial failure criteria is that they fail to describe the geometry of the damage (i.e. pre-failure microcracking) envelope with progressive stress; it is commonly assumed that the damage envelope is parallel to the ultimate brittle failure envelope. Here we use previously published polyaxial failure data for the Shirahama sandstone and Westerley granite to illustrate that the commonly used Mohr-Coulomb and polyaxial failure criteria do not sufficiently describe or capture failure or damage envelopes under true triaxial stress states

  1. Envelope enhancement increases cortical sensitivity to interaural envelope delays with acoustic and electric hearing.

    Directory of Open Access Journals (Sweden)

    Douglas E H Hartley

    Full Text Available Evidence from human psychophysical and animal electrophysiological studies suggests that sensitivity to interaural time delay (ITD in the modulating envelope of a high-frequency carrier can be enhanced using half-wave rectified stimuli. Recent evidence has shown potential benefits of equivalent electrical stimuli to deaf individuals with bilateral cochlear implants (CIs. In the current study we assessed the effects of envelope shape on ITD sensitivity in the primary auditory cortex of normal-hearing ferrets, and profoundly-deaf animals with bilateral CIs. In normal-hearing animals, cortical sensitivity to ITDs (±1 ms in 0.1-ms steps was assessed in response to dichotically-presented i sinusoidal amplitude-modulated (SAM and ii half-wave rectified (HWR tones (100-ms duration; 70 dB SPL presented at the best-frequency of the unit over a range of modulation frequencies. In separate experiments, adult ferrets were deafened with neomycin administration and bilaterally-implanted with intra-cochlear electrode arrays. Electrically-evoked auditory brainstem responses (EABRs were recorded in response to bipolar electrical stimulation of the apical pair of electrodes with singe biphasic current pulses (40 µs per phase over a range of current levels to measure hearing thresholds. Subsequently, we recorded cortical sensitivity to ITDs (±800 µs in 80-µs steps within the envelope of SAM and HWR biphasic-pulse trains (40 µs per phase; 6000 pulses per second, 100-ms duration over a range of modulation frequencies. In normal-hearing animals, nearly a third of cortical neurons were sensitive to envelope-ITDs in response to SAM tones. In deaf animals with bilateral CI, the proportion of ITD-sensitive cortical neurons was approximately a fifth in response to SAM pulse trains. In normal-hearing and deaf animals with bilateral CI the proportion of ITD sensitive units and neural sensitivity to ITDs increased in response to HWR, compared with SAM stimuli

  2. Evolution of close binaries and the formation of pulsars

    International Nuclear Information System (INIS)

    Van Den Heuvel, E.P.J.

    1981-01-01

    The various ways in which compact objects (neutron stars and black holes) may be formed in interacting binary systems are examined. Attention is given to the final evolution of the primary star in a close binary system as a function of the time of Roche-lobe overflow relative to the onset of helium burning, and conditions on primary mass and orbital period leading to the appearance of a compact remnant are noted. Consideration of the fate of the stellar envelope in stars that directly evolve to core collapse indicates that binaries that evolve with conservation of total mass and orbital angular momentum will eventually become systems of two runaway pulsars. In cases of nonconservative evolution, the final state is expected to be a young runaway pulsar with a low- or moderate mass runaway star companion, or a low-mass population I X-ray binary with high space velocity. Compact objects may also be formed when a white dwarf of suitable chemical composition is driven over the Chandrasehkar limit by accretion, resulting in a low-mass X-ray binary

  3. Different velocities in wave trains: early definitions and interpretations

    International Nuclear Information System (INIS)

    Lombardi, Anna M

    2002-01-01

    Recent experiments force us to re-examine the physical significance of the different velocities which one can introduce to describe the propagation of a wave train. In this paper we collect together the early definitions of these velocities, and their physical interpretations, dating back to the end of the 19th and to the first decades of the 20th century. Our purpose is to examine the scientific contexts in which some relevant definitions of velocities emerged, with particular attention paid to the early definitions of the group velocity. We recall some debates in which the group velocity had a dominant role, in order to follow the evolution of the physical meanings that have been ascribed to it. Finally, we focus our attention on the connection between the introduction of the group velocity and the problem of white light

  4. Pulsar velocity observations: Correlations, interpretations, and discussion

    International Nuclear Information System (INIS)

    Helfand, D.J.; Tademaru, E.

    1977-01-01

    From an examination of the current sample of 12 pulsars with measured proper motions and the z-distribution of the much larger group of over 80 sources with measured period derivatives, we develop a self-consistent picture of pulsar evolution. The apparent tendency of pulsars to move parallel to the galactic plane is explained as the result of various selection effects. A method for calculating the unmeasurable radial velocity of a pulsar is presented; it is shown that the total space velocities thus obtained are consistent with the assumption of an extreme Population I origin for pulsars which subsequently move away from the plane with a large range of velocities. The time scale for pulsar magnetic field decay is derived from dynamical considerations. A strong correlation of the original pulsar field strength with the magnitude of pulsar velocity is discussed. This results in the division of pulsars into two classes: Class A sources characterized by low space velocities, a small scale height, and low values of P 0 P 0 ; and Class B sources with a large range of velocities (up to 1000 km s -1 ), a much greater scale height, and larger values of initial field strength. It is postulated that Class A sources originate in tight binaries where their impulse acceleration at birth is insufficient to remove them from the system, while the Class B sources arise from single stars or loosely bound binaries and are accelerated to high velocities by their asymmetric radiation force. The evolutionary picture which is developed is shown to be consistent with a number of constraints imposed by supernova rates, the relative frequency of massive binaries and Class A sources, theoretical field-decay times, and the overall pulsar galactic distribution

  5. Selecting Energy Efficient Building Envelope Retrofits to Existing Department of Defense Building Using Value Focused Thinking

    National Research Council Canada - National Science Library

    Pratt, David M

    2006-01-01

    ... these facilities that have the greatest potential for energy efficient building envelope retrofits. There are hundreds of various new building envelope technologies available to retrofit an existing building envelope, including window, roof, and wall technologies...

  6. Nonlinear evolution of MHD instabilities

    International Nuclear Information System (INIS)

    Bateman, G.; Hicks, H.R.; Wooten, J.W.; Dory, R.A.

    1975-01-01

    A 3-D nonlinear MHD computer code was used to study the time evolution of internal instabilities. Velocity vortex cells are observed to persist into the nonlinear evolution. Pressure and density profiles convect around these cells for a weak localized instability, or convect into the wall for a strong instability. (U.S.)

  7. 14 CFR 23.333 - Flight envelope.

    Science.gov (United States)

    2010-01-01

    ...,000 feet to 38 f.p.s. at 50,000 feet. (2) The following assumptions must be made: (i) The shape of the... altitudes between sea level and 20,000 feet. The gust velocity may be reduced linearly from 50 f.p.s. at 20,000 feet to 25 f.p.s. at 50,000 feet. (ii) Positive and negative gusts of 25 f.p.s. at V D must be...

  8. Critical point analysis of phase envelope diagram

    Energy Technology Data Exchange (ETDEWEB)

    Soetikno, Darmadi; Siagian, Ucok W. R. [Department of Petroleum Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Kusdiantara, Rudy, E-mail: rkusdiantara@s.itb.ac.id; Puspita, Dila, E-mail: rkusdiantara@s.itb.ac.id; Sidarto, Kuntjoro A., E-mail: rkusdiantara@s.itb.ac.id; Soewono, Edy; Gunawan, Agus Y. [Department of Mathematics, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2014-03-24

    Phase diagram or phase envelope is a relation between temperature and pressure that shows the condition of equilibria between the different phases of chemical compounds, mixture of compounds, and solutions. Phase diagram is an important issue in chemical thermodynamics and hydrocarbon reservoir. It is very useful for process simulation, hydrocarbon reactor design, and petroleum engineering studies. It is constructed from the bubble line, dew line, and critical point. Bubble line and dew line are composed of bubble points and dew points, respectively. Bubble point is the first point at which the gas is formed when a liquid is heated. Meanwhile, dew point is the first point where the liquid is formed when the gas is cooled. Critical point is the point where all of the properties of gases and liquids are equal, such as temperature, pressure, amount of substance, and others. Critical point is very useful in fuel processing and dissolution of certain chemicals. Here in this paper, we will show the critical point analytically. Then, it will be compared with numerical calculations of Peng-Robinson equation by using Newton-Raphson method. As case studies, several hydrocarbon mixtures are simulated using by Matlab.

  9. Critical point analysis of phase envelope diagram

    International Nuclear Information System (INIS)

    Soetikno, Darmadi; Siagian, Ucok W. R.; Kusdiantara, Rudy; Puspita, Dila; Sidarto, Kuntjoro A.; Soewono, Edy; Gunawan, Agus Y.

    2014-01-01

    Phase diagram or phase envelope is a relation between temperature and pressure that shows the condition of equilibria between the different phases of chemical compounds, mixture of compounds, and solutions. Phase diagram is an important issue in chemical thermodynamics and hydrocarbon reservoir. It is very useful for process simulation, hydrocarbon reactor design, and petroleum engineering studies. It is constructed from the bubble line, dew line, and critical point. Bubble line and dew line are composed of bubble points and dew points, respectively. Bubble point is the first point at which the gas is formed when a liquid is heated. Meanwhile, dew point is the first point where the liquid is formed when the gas is cooled. Critical point is the point where all of the properties of gases and liquids are equal, such as temperature, pressure, amount of substance, and others. Critical point is very useful in fuel processing and dissolution of certain chemicals. Here in this paper, we will show the critical point analytically. Then, it will be compared with numerical calculations of Peng-Robinson equation by using Newton-Raphson method. As case studies, several hydrocarbon mixtures are simulated using by Matlab

  10. The eikonal equation, envelopes and contact transformations

    International Nuclear Information System (INIS)

    Frittelli, Simonetta; Kamran, Niky; Newman, Ezra T

    2003-01-01

    We begin with an arbitrary but given conformal Lorentzian metric on an open neighbourhood, U, of a four-dimensional manifold (spacetime) and study families of solutions of the eikonal equation. In particular, the families that are of interest to us are the complete solutions. Their level surfaces form a two-parameter (points of S 2 ) family of foliations of U. We show that, from such a complete solution, it is possible to derive a pair of second-order PDEs defined solely on the parameter space S 2 , i.e., they have no reference to the spacetime points. We then show that if one uses the classical envelope method for the construction of new complete solutions from any given complete solution, then the new pair of PDEs (found from the new complete solution) is related to the old pair by contact transformations in the second jet bundle over S 2 . Further, we demonstrate that the pair of second-order PDEs obtained in this manner from any complete solution lies in a subclass of all pairs of second-order PDEs defined by the vanishing of a certain function obtained from the pair and is referred to as the generalized-Wuenschmann invariant. For completeness we briefly discuss the analogous issues associated with the eikonal equation in three dimensions. Finally we point out that conformally invariant geometric structures from the Lorentzian manifold have natural counterparts in the second jet bundle over S 2 on which the pair of PDEs lives

  11. Ecosystem functioning is enveloped by hydrometeorological variability.

    Science.gov (United States)

    Pappas, Christoforos; Mahecha, Miguel D; Frank, David C; Babst, Flurin; Koutsoyiannis, Demetris

    2017-09-01

    Terrestrial ecosystem processes, and the associated vegetation carbon dynamics, respond differently to hydrometeorological variability across timescales, and so does our scientific understanding of the underlying mechanisms. Long-term variability of the terrestrial carbon cycle is not yet well constrained and the resulting climate-biosphere feedbacks are highly uncertain. Here we present a comprehensive overview of hydrometeorological and ecosystem variability from hourly to decadal timescales integrating multiple in situ and remote-sensing datasets characterizing extra-tropical forest sites. We find that ecosystem variability at all sites is confined within a hydrometeorological envelope across sites and timescales. Furthermore, ecosystem variability demonstrates long-term persistence, highlighting ecological memory and slow ecosystem recovery rates after disturbances. However, simulation results with state-of-the-art process-based models do not reflect this long-term persistent behaviour in ecosystem functioning. Accordingly, we develop a cross-time-scale stochastic framework that captures hydrometeorological and ecosystem variability. Our analysis offers a perspective for terrestrial ecosystem modelling and paves the way for new model-data integration opportunities in Earth system sciences.

  12. Multidisk neutron velocity selectors

    International Nuclear Information System (INIS)

    Hammouda, B.

    1992-01-01

    Helical multidisk velocity selectors used for neutron scattering applications have been analyzed and tested experimentally. Design and performance considerations are discussed along with simple explanation of the basic concept. A simple progression is used for the inter-disk spacing in the 'Rosta' design. Ray tracing computer investigations are presented in order to assess the 'coverage' (how many absorbing layers are stacked along the path of 'wrong' wavelength neutrons) and the relative number of neutrons absorbed in each disk (and therefore the relative amount of gamma radiation emitted from each disk). We discuss whether a multidisk velocity selector can be operated in the 'reverse' configuration (i.e. the selector is turned by 180 0 around a vertical axis with the rotor spun in the reverse direction). Experimental tests and calibration of a multidisk selector are reported together with evidence that a multidisk selector can be operated in the 'reverse' configuration. (orig.)

  13. The Velocity Distribution of Isolated Radio Pulsars

    Science.gov (United States)

    Arzoumanian, Z.; Chernoff, D. F.; Cordes, J. M.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We infer the velocity distribution of radio pulsars based on large-scale 0.4 GHz pulsar surveys. We do so by modelling evolution of the locations, velocities, spins, and radio luminosities of pulsars; calculating pulsed flux according to a beaming model and random orientation angles of spin and beam; applying selection effects of pulsar surveys; and comparing model distributions of measurable pulsar properties with survey data using a likelihood function. The surveys analyzed have well-defined characteristics and cover approx. 95% of the sky. We maximize the likelihood in a 6-dimensional space of observables P, dot-P, DM, absolute value of b, mu, F (period, period derivative, dispersion measure, Galactic latitude, proper motion, and flux density). The models we test are described by 12 parameters that characterize a population's birth rate, luminosity, shutoff of radio emission, birth locations, and birth velocities. We infer that the radio beam luminosity (i) is comparable to the energy flux of relativistic particles in models for spin-driven magnetospheres, signifying that radio emission losses reach nearly 100% for the oldest pulsars; and (ii) scales approximately as E(exp 1/2) which, in magnetosphere models, is proportional to the voltage drop available for acceleration of particles. We find that a two-component velocity distribution with characteristic velocities of 90 km/ s and 500 km/ s is greatly preferred to any one-component distribution; this preference is largely immune to variations in other population parameters, such as the luminosity or distance scale, or the assumed spin-down law. We explore some consequences of the preferred birth velocity distribution: (1) roughly 50% of pulsars in the solar neighborhood will escape the Galaxy, while approx. 15% have velocities greater than 1000 km/ s (2) observational bias against high velocity pulsars is relatively unimportant for surveys that reach high Galactic absolute value of z distances, but is severe for

  14. IRC +10 216 in 3D: morphology of a TP-AGB star envelope

    Science.gov (United States)

    Guélin, M.; Patel, N. A.; Bremer, M.; Cernicharo, J.; Castro-Carrizo, A.; Pety, J.; Fonfría, J. P.; Agúndez, M.; Santander-García, M.; Quintana-Lacaci, G.; Velilla Prieto, L.; Blundell, R.; Thaddeus, P.

    2018-02-01

    During their late pulsating phase, AGB stars expel most of their mass in the form of massive dusty envelopes, an event that largely controls the composition of interstellar matter. The envelopes, however, are distant and opaque to visible and NIR radiation: their structure remains poorly known and the mass-loss process poorly understood. Millimeter-wave interferometry, which combines the advantages of longer wavelength, high angular resolution and very high spectral resolution is the optimal investigative tool for this purpose. Mm waves pass through dust with almost no attenuation. Their spectrum is rich in molecular lines and hosts the fundamental lines of the ubiquitous CO molecule, allowing a tomographic reconstruction of the envelope structure. The circumstellar envelope IRC +10 216 and its central star, the C-rich TP-AGB star closest to the Sun, are the best objects for such an investigation. Two years ago, we reported the first detailed study of the CO(2-1) line emission in that envelope, made with the IRAM 30-m telescope. It revealed a series of dense gas shells, expanding at a uniform radial velocity. The limited resolution of the telescope (HPBW 11″) did not allow us to resolve the shell structure. We now report much higher angular resolution observations of CO(2-1), CO(1-0), CN(2-1) and C4H(24-23) made with the SMA, PdB and ALMA interferometers (with synthesized half-power beamwidths of 3″, 1″ and 0.3″, respectively). Although the envelope appears much more intricate at high resolution than with an 11″ beam, its prevailing structure remains a pattern of thin, nearly concentric shells. The average separation between the brightest CO shells is 16″ in the outer envelope, where it appears remarkably constant. Closer to the star (system with a period of 700 yr and a near face-on elliptical orbit. The companion fly-by triggers enhanced episodes of mass loss near periastron. The densification of the shell pattern observed in the central part of the

  15. Formation of Planetary Populations I: Metallicity & Envelope Opacity Effects

    Science.gov (United States)

    Alessi, Matthew; Pudritz, Ralph E.

    2018-05-01

    We present a comprehensive body of simulations of the formation of exoplanetary populations that incorporate the role of planet traps in slowing planetary migration. The traps we include in our model are the water ice line, the disk heat transition, and the dead zone outer edge. We reduce our model parameter set to two physical parameters: the opacity of the accreting planetary atmospheres (κenv) and a measure of the efficiency of planetary accretion after gap opening (fmax). We perform planet population synthesis calculations based on the initial observed distributions of host star and disk properties - their disk masses, lifetimes, and stellar metallicities. We find the frequency of giant planet formation scales with disk metallicity, in agreement with the observed Jovian planet frequency-metallicity relation. We consider both X-ray and cosmic ray disk ionization models, whose differing ionization rates lead to different dead zone trap locations. In both cases, Jovian planets form in our model out to 2-3 AU, with a distribution at smaller radii dependent on the disk ionization source and the setting of envelope opacity. We find that low values of κenv (0.001-0.002 cm2 g-1) and X-ray disk ionization are necessary to obtain a separation between hot Jupiters near 0.1 AU, and warm Jupiters outside 0.6 AU, a feature present in the data. Our model also produces a large number of super Earths, but the majority are outside of 2 AU. As our model assumes a constant dust to gas ratio, we suggest that radial dust evolution must be taken into account to reproduce the observed super Earth population.

  16. DATA ENVELOPMENT ANALYSIS OF BANKING SECTOR IN BANGLADESH

    Directory of Open Access Journals (Sweden)

    Md. Rashedul Hoque

    2012-05-01

    Full Text Available Banking sector of Bangladesh is flourishing and contributing to its economy. In this aspect measuring efficiency is important. Data Envelopment Analysis technique is used for this purpose. The data are collected from the annual reports of twenty four different banks in Bangladesh. Data Envelopment Analysis is mainly of two types - constant returns to scale and variable returns to scale. Since this study attempts to maximize output, so the output oriented Data Envelopment Analysis is used. The most efficient bank is one that obtains the highest efficiency score.

  17. Pre-paid envelopes commemorating the 2013 Open Days

    CERN Multimedia

    2013-01-01

    The post office on CERN's Prévessin site is still selling pre-paid envelopes commemorating the 2013 Open Days. Hurry while stocks last!   The special envelopes, which are valid in France for non-priority letters weighing up to 20 grams, are ideal for your Christmas and New Year correspondence. A set of ten envelopes, each featuring a different image, costs € 8.70 or 10 CHF. The post office is located in Building 866 on the Prévessin site and is open Mondays to Thursdays from 9.30 a.m. to 12.30 p.m.

  18. Three-Dimensional Coupled NLS Equations for Envelope Gravity Solitary Waves in Baroclinic Atmosphere and Modulational Instability

    Directory of Open Access Journals (Sweden)

    Baojun Zhao

    2018-01-01

    Full Text Available Envelope gravity solitary waves are an important research hot spot in the field of solitary wave. And the weakly nonlinear model equations system is a part of the research of envelope gravity solitary waves. Because of the lack of technology and theory, previous studies tried hard to reduce the variable numbers and constructed the two-dimensional model in barotropic atmosphere and could only describe the propagation feature in a direction. But for the propagation of envelope gravity solitary waves in real ocean ridges and atmospheric mountains, the three-dimensional model is more appropriate. Meanwhile, the baroclinic problem of atmosphere is also an inevitable topic. In the paper, the three-dimensional coupled nonlinear Schrödinger (CNLS equations are presented to describe the evolution of envelope gravity solitary waves in baroclinic atmosphere, which are derived from the basic dynamic equations by employing perturbation and multiscale methods. The model overcomes two disadvantages: (1 baroclinic problem and (2 propagation path problem. Then, based on trial function method, we deduce the solution of the CNLS equations. Finally, modulational instability of wave trains is also discussed.

  19. Genetic algorithm for building envelope calibration

    International Nuclear Information System (INIS)

    Ramos Ruiz, Germán; Fernández Bandera, Carlos; Gómez-Acebo Temes, Tomás; Sánchez-Ostiz Gutierrez, Ana

    2016-01-01

    Highlights: • Calibration methodology using Multi-Objective Genetic Algorithm (NSGA-II). • Uncertainty analysis formulas implemented directly in EnergyPlus. • The methodology captures the heat dynamic of the building with a high level of accuracy. • Reduction in the number of parameters involved due to sensitivity analysis. • Cost-effective methodology using temperature sensors only. - Abstract: Buildings today represent 40% of world primary energy consumption and 24% of greenhouse gas emissions. In our society there is growing interest in knowing precisely when and how energy consumption occurs. This means that consumption measurement and verification plans are well-advanced. International agencies such as Efficiency Valuation Organization (EVO) and International Performance Measurement and Verification Protocol (IPMVP) have developed methodologies to quantify savings. This paper presents a methodology to accurately perform automated envelope calibration under option D (calibrated simulation) of IPMVP – vol. 1. This is frequently ignored because of its complexity, despite being more flexible and accurate in assessing the energy performance of a building. A detailed baseline energy model is used, and by means of a metaheuristic technique achieves a highly reliable and accurate Building Energy Simulation (BES) model suitable for detailed analysis of saving strategies. In order to find this BES model a Genetic Algorithm (NSGA-II) is used, together with a highly efficient engine to stimulate the objective, thus permitting rapid achievement of the goal. The result is a BES model that broadly captures the heat dynamic behaviour of the building. The model amply fulfils the parameters demanded by ASHRAE and EVO under option D.

  20. Optimizing velocities and transports for complex coastal regions and archipelagos

    OpenAIRE

    Haley, Patrick; Agarwal, Arpit; Lermusiaux, Pierre

    2015-01-01

    We derive and apply a methodology for the initialization of velocity and transport fields in complex multiply-connected regions with multiscale dynamics. The result is initial fields that are consistent with observations, complex geometry and dynamics, and that can simulate the evolution of ocean processes without large spurious initial transients. A class of constrained weighted least squares optimizations is defined to best fit first-guess velocities while satisfying the complex bathymetry,...

  1. Flight envelope protection system for unmanned aerial vehicles

    KAUST Repository

    Claudel, Christian G.; Shaqura, Mohammad

    2016-01-01

    Systems and methods to protect the flight envelope in both manual flight and flight by a commercial autopilot are provided. A system can comprise: an inertial measurement unit (IMU); a computing device in data communication with the IMU

  2. Envelope Protection for In-Flight Ice Contamination

    Science.gov (United States)

    Gingras, David R.; Barnhart, Billy P.; Ranaudo, Richard J.; Ratvasky, Thomas P.; Morelli, Eugene A.

    2010-01-01

    Fatal loss-of-control (LOC) accidents have been directly related to in-flight airframe icing. The prototype system presented in this paper directly addresses the need for real-time onboard envelope protection in icing conditions. The combinations of a-priori information and realtime aerodynamic estimations are shown to provide sufficient input for determining safe limits of the flight envelope during in-flight icing encounters. The Icing Contamination Envelope Protection (ICEPro) system has been designed and implemented to identify degradations in airplane performance and flying qualities resulting from ice contamination and provide safe flight-envelope cues to the pilot. Components of ICEPro are described and results from preliminary tests are presented.

  3. that Bind Specifically to Recombinant Envelope Protein of Dengue

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research June 2015; 14 (6): 997-1003 ... Revised accepted: 30 April 2015. Abstract ... Results: The 45 KDa, 43 KDa and 30 KDa plasma membrane proteins were identified as viral envelope targets.

  4. Early Site Permit Demonstration Program: Plant parameters envelope report

    International Nuclear Information System (INIS)

    1993-03-01

    The Early Site Permit (ESP) Demonstration Program is the nuclear industry's initiative for piloting the early resolution of siting-related issues before the detailed design proceedings of the combined operating license review. The ESP Demonstration Program consists of three phases. The plant parameters envelopes task is part of Phase 1, which addresses the generic review of applicable federal regulations and develops criteria for safety and environmental assessment of potential sites. The plant parameters envelopes identify parameters that characterize the interface between an ALWR design and a potential site, and quantify the interface through values selected from the Utility Requirements Documents, vendor design information, or engineering assessments. When augmented with site-specific information, the plant parameters envelopes provide sufficient information to allow ESPs to be granted based on individual ALWR design information or enveloping design information for the evolutionary, passive, or generic ALWR plants. This document is expected to become a living document when used by future applicants

  5. Transport of Ions Across the Inner Envelope Membrane of Chloroplasts

    International Nuclear Information System (INIS)

    McCarty, R. E.

    2004-01-01

    The technical report outlines the results of nine years of research on how ions cross the inner envelope membrane of chloroplasts. The ions include protons, nitrite, calcium and ferrous iron. Bicarbonate transport was also studied

  6. Intelligent building envelopes. Architectural concept and applications for daylighting quality

    Energy Technology Data Exchange (ETDEWEB)

    Wyckmans, Annemie

    2005-11-15

    How does an intelligent building envelope manage the variable and sometimes conflictive occupant requirements that arise in a day lit indoor environment. This is the research question that provides the basis for this Ph.D. work. As it touches upon several fields of application, the research question is untangled into four steps, each of which corresponds to a chapter of the thesis. 1) What characterises intelligent behaviour for a building envelope. 2) What characterises indoor day lighting quality. 3) Which functions can an intelligent building envelope be expected to perform in the context of day lighting quality. 4) How are the materials, components and composition of an intelligent building envelope designed to influence this performance. The emphasis is on design, environmental aspects, energy conservation, functional analysis and physical applications.

  7. Torsin Mediates Primary Envelopment of Large Ribonucleoprotein Granules at the Nuclear Envelope

    Directory of Open Access Journals (Sweden)

    Vahbiz Jokhi

    2013-04-01

    Full Text Available A previously unrecognized mechanism through which large ribonucleoprotein (megaRNP granules exit the nucleus is by budding through the nuclear envelope (NE. This mechanism is akin to the nuclear egress of herpes-type viruses and is essential for proper synapse development. However, the molecular machinery required to remodel the NE during this process is unknown. Here, we identify Torsin, an AAA-ATPase that in humans is linked to dystonia, as a major mediator of primary megaRNP envelopment during NE budding. In torsin mutants, megaRNPs accumulate within the perinuclear space, and the messenger RNAs contained within fail to reach synaptic sites, preventing normal synaptic protein synthesis and thus proper synaptic bouton development. These studies begin to establish the cellular machinery underlying the exit of megaRNPs via budding, offer an explanation for the “nuclear blebbing” phenotype found in dystonia models, and provide an important link between Torsin and the synaptic phenotypes observed in dystonia.

  8. Aspherical Dust Envelopes Around Oxygen-Rich AGB Stars

    Directory of Open Access Journals (Sweden)

    Kyung-Won Suh

    2006-12-01

    Full Text Available We model the aspherical dust envelopes around O-rich AGB stars. We perform the radiative transfer model calculations for axisymmetric dust distributions. We simulate what could be observed from the aspherical dust envelopes around O-rich AGB stars by presenting the model spectral energy distributions and images at various wavelengths for different optical depths and viewing angles. The model results are very different from the ones with spherically symmetric geometry.

  9. Failure envelope approach for consolidated undrained capacity of shallow foundations

    OpenAIRE

    Vulpe, Cristina; Gourvenec, Susan; Leman, Billy; Fung, Kah Ngii

    2016-01-01

    A generalized framework is applied to predict consolidated undrained VHM failure envelopes for surface circular and strip foundations. The failure envelopes for consolidated undrained conditions are shown to be scaled from those for unconsolidated undrained conditions by the uniaxial consolidated undrained capacities, which are predicted through a theoretical framework based on fundamental critical state soil mechanics. The framework is applied to results from small-strain finite-element anal...

  10. Preserving Envelope Efficiency in Performance Based Code Compliance

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, Brian A. [Thornton Energy Consulting (United States); Sullivan, Greg P. [Efficiency Solutions (United States); Rosenberg, Michael I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Baechler, Michael C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-06-20

    The City of Seattle 2012 Energy Code (Seattle 2014), one of the most progressive in the country, is under revision for its 2015 edition. Additionally, city personnel participate in the development of the next generation of the Washington State Energy Code and the International Energy Code. Seattle has pledged carbon neutrality by 2050 including buildings, transportation and other sectors. The United States Department of Energy (DOE), through Pacific Northwest National Laboratory (PNNL) provided technical assistance to Seattle in order to understand the implications of one potential direction for its code development, limiting trade-offs of long-lived building envelope components less stringent than the prescriptive code envelope requirements by using better-than-code but shorter-lived lighting and heating, ventilation, and air-conditioning (HVAC) components through the total building performance modeled energy compliance path. Weaker building envelopes can permanently limit building energy performance even as lighting and HVAC components are upgraded over time, because retrofitting the envelope is less likely and more expensive. Weaker building envelopes may also increase the required size, cost and complexity of HVAC systems and may adversely affect occupant comfort. This report presents the results of this technical assistance. The use of modeled energy code compliance to trade-off envelope components with shorter-lived building components is not unique to Seattle and the lessons and possible solutions described in this report have implications for other jurisdictions and energy codes.

  11. A Search for Phosphine in Circumstellar Envelopes: PH3 in IRC +10216 and CRL 2688?

    Science.gov (United States)

    Tenenbaum, E. D.; Ziurys, L. M.

    2008-06-01

    We present the results of a search for the JK = 10→ 00 transition of PH3 (phosphine) at 267 GHz toward several circumstellar envelopes using the Arizona Radio Observatory 10 m Submillimeter Telescope (SMT). In the carbon-rich shells of IRC +10216 and CRL 2688, we have detected emission lines exactly at the PH3 frequency. Toward the oxygen-rich supergiant VY Canis Majoris, only an upper limit was obtained, while in the evolved carbon-rich proto-planetary nebula CRL 618, the transition is contaminated by vibrationally excited HC3N (ν7 = 4). The line shape in IRC +10216 appears to consist of two distinct components: a flat-topped profile with a width of ~28 km s-1, as is typical for this source, and a narrower feature approximately 4 km s-1 wide. The narrow component likely arises from the inner envelope (r < 8R*) where the gas has not reached the terminal expansion velocity, or it is nonthermal emission. Based on the broader component, the abundance of PH3 with respect to H2 is estimated to be 5 × 10-8 in a region with a radius of r < 150R*. If the narrower component is thermal, it implies a phosphine abundance of ~5 × 10-7 close to the stellar photosphere (r < 8R*). In CRL 2688, the PH3 abundance is less constrained, with plausible values ranging from 3 × 10-8 to 4 × 10-7, assuming a spherical distribution. Phosphine appears to be present in large concentrations in the inner envelope of C-rich AGB stars, and thus may function as a parent molecule for other phosphorus species.

  12. Velocity Dispersion of Ionized Gas and Multiple Supernova Explosions

    Directory of Open Access Journals (Sweden)

    Vasiliev E. O.

    2015-06-01

    Full Text Available We use 3D numerical simulations to study the evolution of the Hα intensity and velocity dispersion for single and multiple supernova (SN explosions. We find that the IHα– σ diagram obtained for simulated gas flows is similar in shape to that observed in dwarf galaxies. We conclude that colliding SN shells with significant difference in age are responsible for high velocity dispersion that reaches up to ≳ 100 km s−1. Such a high velocity dispersion could be hardly obtained for a single SN remnant. Peaks of velocity dispersion in the IHα– σ diagram may correspond to several isolated or merged SN remnants with moderately different ages. Degrading the spatial resolution in the Hα intensity and velocity dispersion maps makes the simulated IHα– σ diagrams close to those observed in dwarf galaxies not only in shape, but also quantitatively.

  13. Examples of Vector Velocity Imaging

    DEFF Research Database (Denmark)

    Hansen, Peter M.; Pedersen, Mads M.; Hansen, Kristoffer L.

    2011-01-01

    To measure blood flow velocity in vessels with conventional ultrasound, the velocity is estimated along the direction of the emitted ultrasound wave. It is therefore impossible to obtain accurate information on blood flow velocity and direction, when the angle between blood flow and ultrasound wa...

  14. Accuracy of inference on the physics of binary evolution from gravitational-wave observations

    Science.gov (United States)

    Barrett, Jim W.; Gaebel, Sebastian M.; Neijssel, Coenraad J.; Vigna-Gómez, Alejandro; Stevenson, Simon; Berry, Christopher P. L.; Farr, Will M.; Mandel, Ilya

    2018-04-01

    The properties of the population of merging binary black holes encode some of the uncertain physics underlying the evolution of massive stars in binaries. The binary black hole merger rate and chirp-mass distribution are being measured by ground-based gravitational-wave detectors. We consider isolated binary evolution, and explore how accurately the physical model can be constrained with such observations by applying the Fisher information matrix to the merging black hole population simulated with the rapid binary-population synthesis code COMPAS. We investigate variations in four COMPAS parameters: common-envelope efficiency, kick-velocity dispersion, and mass-loss rates during the luminous blue variable and Wolf-Rayet stellar-evolutionary phases. We find that ˜1000 observations would constrain these model parameters to a fractional accuracy of a few per cent. Given the empirically determined binary black hole merger rate, we can expect gravitational-wave observations alone to place strong constraints on the physics of stellar and binary evolution within a few years. Our approach can be extended to use other observational data sets; combining observations at different evolutionary stages will lead to a better understanding of stellar and binary physics.

  15. Modified Feynman ratchet with velocity-dependent fluctuations

    Directory of Open Access Journals (Sweden)

    Jack Denur

    2004-03-01

    Full Text Available Abstract: The randomness of Brownian motion at thermodynamic equilibrium can be spontaneously broken by velocity-dependence of fluctuations, i.e., by dependence of values or probability distributions of fluctuating properties on Brownian-motional velocity. Such randomness-breaking can spontaneously obtain via interaction between Brownian-motional Doppler effects --- which manifest the required velocity-dependence --- and system geometrical asymmetry. A non random walk is thereby spontaneously superposed on Brownian motion, resulting in a systematic net drift velocity despite thermodynamic equilibrium. The time evolution of this systematic net drift velocity --- and of velocity probability density, force, and power output --- is derived for a velocity-dependent modification of Feynman's ratchet. We show that said spontaneous randomness-breaking, and consequent systematic net drift velocity, imply: bias from the Maxwellian of the system's velocity probability density, the force that tends to accelerate it, and its power output. Maximization, especially of power output, is discussed. Uncompensated decreases in total entropy, challenging the second law of thermodynamics, are thereby implied.

  16. LITHIUM DEPLETION IS A STRONG TEST OF CORE-ENVELOPE RECOUPLING

    International Nuclear Information System (INIS)

    Somers, Garrett; Pinsonneault, Marc H.

    2016-01-01

    Rotational mixing is a prime candidate for explaining the gradual depletion of lithium from the photospheres of cool stars during the main sequence. However, previous mixing calculations have relied primarily on treatments of angular momentum transport in stellar interiors incompatible with solar and stellar data in the sense that they overestimate the internal differential rotation. Instead, recent studies suggest that stars are strongly differentially rotating at young ages but approach a solid body rotation during their lifetimes. We modify our rotating stellar evolution code to include an additional source of angular momentum transport, a necessary ingredient for explaining the open cluster rotation pattern, and examine the consequences for mixing. We confirm that core-envelope recoupling with a ∼20 Myr timescale is required to explain the evolution of the mean rotation pattern along the main sequence, and demonstrate that it also provides a more accurate description of the Li depletion pattern seen in open clusters. Recoupling produces a characteristic pattern of efficient mixing at early ages and little mixing at late ages, thus predicting a flattening of Li depletion at a few Gyr, in agreement with the observed late-time evolution. Using Li abundances we argue that the timescale for core-envelope recoupling during the main sequence decreases sharply with increasing mass. We discuss the implications of this finding for stellar physics, including the viability of gravity waves and magnetic fields as agents of angular momentum transport. We also raise the possibility of intrinsic differences in initial conditions in star clusters using M67 as an example.

  17. The circumstellar envelopes of F and G type supergiants in the large magellanic cloud

    International Nuclear Information System (INIS)

    Hagen, W.; Humphreys, R.M.; Stencel, R.E.

    1981-01-01

    We have obtained high-dispersion echellograms at 2.5 and 5.1 A/mm of four F and G-type supergiants (Msub(V) approximately -9) in the large Magellanic Cloud for the purpose of studying their outer atmospheres as compared to their Milky Way counterparts. Line doubling at Na I D indicates extensive circumstellar envelopes and mass loss rates in excess of 10 -5 M . yr -1 with outflow velocities of 10-60 km s -1 . Deep exposures at Ca II H and K reveal new information about the chromospheres of extragalactic stars. The presence of H and K wing emission lines augments this, and also provides an independent way of estimating Msub(V). (author)

  18. Integrated energy design of the building envelope

    Energy Technology Data Exchange (ETDEWEB)

    Vraa Nielsen, M.

    2012-07-01

    This thesis describes the outcome of the PhD project Integrated energy design of the building envelope carried out through a combination of scientific dissemination reported through peer-reviewed journals and a wide range of affiliated projects involved in at an architectural firm. The research project analysed how the implementation of technical knowledge early in the building design process can quantify the effect of a building's facades on its energy efficiency and indoor climate and thereby facilitate a more qualified design development. The project was structured in the following way: 1) the importance of integrating knowledge in the early stages of design, and how it can be done; 2) understanding the facade's typology; and 3) the complex notion of comfort. The project touched not only on the technical capabilities and requirements governing facade design, but also the process by which it takes place. This was done by applying the methodology of Integrated Energy Design (IED) and analysing its applicability in the design of facades. A major part of the project was an actual engagement in the architectural process to test out incorporating a consciousness about energy and comfort as part of a more holistic performance evaluation. The research project illustrates the great potential in taking passive properties into account through a geometrical optimisation inherent in the development of the architectural concept. It demonstrates that integration of technical knowledge at the early stages of design not only can qualify the geometrical processing, but also facilitate the design development of the facade. Thereby a more holistic performance optimisation can be obtained through parameters such as overall facade geometry and orientation, functional organisation, room height and depth, facade layout, window geometry and transparency, design of the window aperture, etc. Through the wide range of affiliated project involved in at the architectural firm over

  19. Dynamics of Preferential Substrate Recognition in HIV-1 Protease: Redefining the Substrate Envelope

    Science.gov (United States)

    Özen, Ayşegül; Haliloğlu, Türkan; Schiffer, Celia A.

    2011-01-01

    HIV-1 protease (PR) permits viral maturation by processing the Gag and Gag-Pro-Pol polyproteins. Though HIV-1 PR inhibitors (PIs) are used in combination antiviral therapy, the emergence of drug resistance has limited their efficacy. The rapid evolution of HIV-1 necessitates the consideration of drug resistance in novel drug-design strategies. Drug-resistant HIV-1 PR variants, while no longer efficiently inhibited, continue to efficiently hydrolyze the natural viral substrates. Though highly diverse in sequence, the HIV-1 PR substrates bind in a conserved three-dimensional shape we defined as the “substrate envelope”. We previously showed that resistance mutations arise where PIs protrude beyond the substrate envelope, as these regions are crucial for drug binding but not for substrate recognition. Here, we extend this model by considering the role of protein dynamics in the interaction of HIV-1 PR with its substrates. Seven molecular dynamics simulations of PR-substrate complexes were performed to estimate the conformational flexibility of substrates in their complexes. Interdependency of the substrate-protease interactions may compensate for the variations in cleavage-site sequences, and explain how a diverse set of sequences can be recognized as substrates by the same enzyme. This diversity may be essential for regulating sequential processing of substrates. We also define a dynamic substrate envelope as a more accurate representation of PR-substrate interactions. This dynamic substrate envelope, described by a probability distribution function, is a powerful tool for drug design efforts targeting ensembles of resistant HIV-1 PR variants with the aim of developing drugs that are less susceptible to resistance. PMID:21762811

  20. The South Carolina bridge-scour envelope curves

    Science.gov (United States)

    Benedict, Stephen T.; Feaster, Toby D.; Caldwell, Andral W.

    2016-09-30

    The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a series of three field investigations to evaluate historical, riverine bridge scour in the Piedmont and Coastal Plain regions of South Carolina. These investigations included data collected at 231 riverine bridges, which lead to the development of bridge-scour envelope curves for clear-water and live-bed components of scour. The application and limitations of the South Carolina bridge-scour envelope curves were documented in four reports, each report addressing selected components of bridge scour. The current investigation (2016) synthesizes the findings of these previous reports into a guidance manual providing an integrated procedure for applying the envelope curves. Additionally, the investigation provides limited verification for selected bridge-scour envelope curves by comparing them to field data collected outside of South Carolina from previously published sources. Although the bridge-scour envelope curves have limitations, they are useful supplementary tools for assessing the potential for scour at riverine bridges in South Carolina.

  1. Solar envelope concepts: moderate density building applications. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Knowles, R.L.; Berry, R.D.

    1980-04-01

    Solar energy utilization in urban areas requires public guarantees that all property owners have direct access to the sun. The study examines the implications of this premise in relation to the need for cities to also encourage or accommodate rebuilding and future development. The public policy mechanism for guaranteeing solar access is conceptualized as a solar zoning envelope that allows the largest possible building bulk on a land parcel without shadowing neighboring properties during specified times. Step-by-step methods for generating solar envelopes are described with extensive drawings, showing a variety of urban platting and lot configurations. Development and design possibilities are examined on a selected set of Los Angeles sites with typically diverse urban characteristics. Envelope attributes suitable for encouraging moderate-density commercial and residential building are examined in the context of two hypothetical but realistic development programs: one for speculative office buildings and one for condominium housing. Numerous illustrations of envelope forms and prototypical building designs are provided. The results of development simulation studies on all test sites are tabulated to show building bulk, density, land-coverage and open space characteristics obtainable under the hypothesized envelopes.

  2. Effect of group velocity mismatch on acousto-optic interaction of ultrashort laser pulses

    International Nuclear Information System (INIS)

    Yushkov, K B; Molchanov, V Ya

    2011-01-01

    Equations describing acousto-optic diffraction of ultrashort laser pulses in an anisotropic medium are derived, taking into account the group velocity mismatch of optical eigenmodes. It is shown that the solution of the modified coupled-mode equations taking into account the group delay is characterised by an increase in the pulse duration, a decrease in diffraction efficiency, a change in the shape of the wave packet envelope, as well as by an increase in the width of the transmission function.

  3. INFALLING–ROTATING MOTION AND ASSOCIATED CHEMICAL CHANGE IN THE ENVELOPE OF IRAS 16293–2422 SOURCE A STUDIED WITH ALMA

    Energy Technology Data Exchange (ETDEWEB)

    Oya, Yoko; López-Sepulcre, Ana; Watanabe, Yoshimasa; Yamamoto, Satoshi [Department of Physics, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Sakai, Nami [The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198 (Japan); Ceccarelli, Cecilia; Lefloch, Bertrand; Favre, Cécile, E-mail: oya@taurus.phys.s.u-tokyo.ac.jp [Université Grenoble Alpes, IPAG, F-38000 Grenoble (France)

    2016-06-20

    We have analyzed rotational spectral line emission of OCS, CH{sub 3}OH, HCOOCH{sub 3}, and H{sub 2}CS observed toward the low-mass Class 0 protostellar source IRAS 16293–2422 Source A at a sub-arcsecond resolution (∼0.″6 × 0.″5) with ALMA. Significant chemical differentiation is found on a scale of 50 au. The OCS line is found to trace well the infalling–rotating envelope in this source. On the other hand, the distributions of CH{sub 3}OH and HCOOCH{sub 3} are found to be concentrated around the inner part of the infalling–rotating envelope. With a simple ballistic model of the infalling–rotating envelope, the radius of the centrifugal barrier (a half of the centrifugal radius) and the protostellar mass are evaluated from the OCS data to be from 40 to 60 au and from 0.5 to 1.0 M {sub ⊙}, respectively, assuming the inclination angle of the envelope/disk structure to be 60° (90° for the edge-on configuration). Although the protostellar mass is correlated with the inclination angle, the radius of the centrifugal barrier is not. This is the first indication of the centrifugal barrier of the infalling–rotating envelope in a hot corino source. CH{sub 3}OH and HCOOCH{sub 3} may be liberated from ice mantles by weak accretion shocks around the centrifugal barrier and/or by protostellar heating. The H{sub 2}CS emission seems to come from the disk component inside the centrifugal barrier in addition to the envelope component. The centrifugal barrier plays a central role not only in the formation of a rotationally supported disk but also in the chemical evolution from the envelope to the protoplanetary disk.

  4. Development of an optimal velocity selection method with velocity obstacle

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Geuk; Oh, Jun Ho [KAIST, Daejeon (Korea, Republic of)

    2015-08-15

    The Velocity obstacle (VO) method is one of the most well-known methods for local path planning, allowing consideration of dynamic obstacles and unexpected obstacles. Typical VO methods separate a velocity map into a collision area and a collision-free area. A robot can avoid collisions by selecting its velocity from within the collision-free area. However, if there are numerous obstacles near a robot, the robot will have very few velocity candidates. In this paper, a method for choosing optimal velocity components using the concept of pass-time and vertical clearance is proposed for the efficient movement of a robot. The pass-time is the time required for a robot to pass by an obstacle. By generating a latticized available velocity map for a robot, each velocity component can be evaluated using a cost function that considers the pass-time and other aspects. From the output of the cost function, even a velocity component that will cause a collision in the future can be chosen as a final velocity if the pass-time is sufficiently long enough.

  5. Toward 2D Seismic Wavefield Monitoring: Seismic Gradiometry for Long-Period Seismogram and Short-Period Seismogram Envelope applied to the Hi-net Array

    Science.gov (United States)

    Maeda, T.; Nishida, K.; Takagi, R.; Obara, K.

    2015-12-01

    The high-sensitive seismograph network Japan (Hi-net) operated by National Research Institute for Earth Science and Disaster Prevention (NIED) has about 800 stations with average separation of 20 km. We can observe long-period seismic wave propagation as a 2D wavefield with station separations shorter than wavelength. In contrast, short-period waves are quite incoherent at stations, however, their envelope shapes resemble at neighbor stations. Therefore, we may be able to extract seismic wave energy propagation by seismogram envelope analysis. We attempted to characterize seismic waveform at long-period and its envelope at short-period as 2D wavefield by applying seismic gradiometry. We applied the seismic gradiometry to a synthetic long-period (20-50s) dataset prepared by numerical simulation in realistic 3D medium at the Hi-net station layout. Wave amplitude and its spatial derivatives are estimated by using data at nearby stations. The slowness vector, the radiation pattern and the geometrical spreading are extracted from estimated velocity, displacement and its spatial derivatives. For short-periods at shorter than 1 s, seismogram envelope shows temporal and spatial broadening through scattering by medium heterogeneity. It is expected that envelope shape may be coherent among nearby stations. Based on this idea, we applied the same method to the time-integration of seismogram envelope to estimate its spatial derivatives. Together with seismogram envelope, we succeeded in estimating the slowness vector from the seismogram envelope as well as long-period waveforms by synthetic test, without using phase information. Our preliminarily results show that the seismic gradiometry suits the Hi-net to extract wave propagation characteristics both at long and short periods. This method is appealing that it can estimate waves at homogeneous grid to monitor seismic wave as a wavefield. It is promising to obtain phase velocity variation from direct waves, and to grasp wave

  6. Envelope-like retrotransposons in the plant kingdom: evidence of their presence in gymnosperms (Pinus pinaster).

    Science.gov (United States)

    Miguel, Célia; Simões, Marta; Oliveira, Maria Margarida; Rocheta, Margarida

    2008-11-01

    Retroviruses differ from retrotransposons due to their infective capacity, which depends critically on the encoded envelope. Some plant retroelements contain domains reminiscent of the env of animal retroviruses but the number of such elements described to date is restricted to angiosperms. We show here the first evidence of the presence of putative env-like gene sequences in a gymnosperm species, Pinus pinaster (maritime pine). Using a degenerate primer approach for conserved domains of RNaseH gene, three clones from putative envelope-like retrotransposons (PpRT2, PpRT3, and PpRT4) were identified. The env-like sequences of P. pinaster clones are predicted to encode proteins with transmembrane domains. These sequences showed identity scores of up to 30% with env-like sequences belonging to different organisms. A phylogenetic analysis based on protein alignment of deduced aminoacid sequences revealed that these clones clustered with env-containing plant retrotransposons, as well as with retrotransposons from invertebrate organisms. The differences found among the sequences of maritime pine clones isolated here suggest the existence of different putative classes of env-like retroelements. The identification for the first time of env-like genes in a gymnosperm species may support the ancestrality of retroviruses among plants shedding light on their role in plant evolution.

  7. High frequency vibration analysis by the complex envelope vectorization.

    Science.gov (United States)

    Giannini, O; Carcaterra, A; Sestieri, A

    2007-06-01

    The complex envelope displacement analysis (CEDA) is a procedure to solve high frequency vibration and vibro-acoustic problems, providing the envelope of the physical solution. CEDA is based on a variable transformation mapping the high frequency oscillations into signals of low frequency content and has been successfully applied to one-dimensional systems. However, the extension to plates and vibro-acoustic fields met serious difficulties so that a general revision of the theory was carried out, leading finally to a new method, the complex envelope vectorization (CEV). In this paper the CEV method is described, underlying merits and limits of the procedure, and a set of applications to vibration and vibro-acoustic problems of increasing complexity are presented.

  8. Safety analysis to support a safe operating envelope for fuel

    International Nuclear Information System (INIS)

    Gibb, R.A.; Reid, P.J.

    1998-01-01

    This paper presents an approach for defining a safe operating envelope for fuel. 'Safe operating envelope' is defined as an envelope of fuel parameters defined for application in safety analysis that can be related to, or used to define, the acceptable range of fuel conditions due to operational transients or deviations in fuel manufacturing processes. The paper describes the motivation for developing such a methodology. The methodology involved four steps: the update of fission product inventories, the review of sheath failure criteria, a review of input parameters to be used in fuel modelling codes, and the development of an improved fission product release code. This paper discusses the aspects of fuel sheath failure criteria that pertain to operating or manufacturing conditions and to the evaluation and selection of modelling input data. The other steps are not addressed in this paper since they have been presented elsewhere. (author)

  9. The nuclear envelope from basic biology to therapy.

    Science.gov (United States)

    Worman, Howard J; Foisner, Roland

    2010-02-01

    The nuclear envelope has long been a focus of basic research for a highly specialized group of cell biologists. More recently, an expanding group of scientists and physicians have developed a keen interest in the nuclear envelope since mutations in the genes encoding lamins and associated proteins have been shown to cause a diverse range of human diseases often called laminopathies or nuclear envelopathies. Most of these diseases have tissue-selective phenotypes, suggesting that the nuclear envelope must function in cell-type- and developmental-stage-specific processes such as chromatin organization, regulation of gene expression, controlled nucleocytoplasmic transport and response to stress in metazoans. On 22-23 April 2009, Professor Christopher Hutchison organized the 4th British Nuclear Envelope Disease and Chromatin Organization meeting at the College of St Hild and St Bede at Durham University, sponsored by the Biochemical Society. In attendance were investigators with one common interest, the nuclear envelope, but with diverse expertise and training in animal and plant cell biology, genetics, developmental biology and medicine. We were each honoured to be keynote speakers. This issue of Biochemical Society Transactions contains papers written by some of the presenters at this scientifically exciting meeting, held in a bucolic setting where the food was tasty and the wine flowed freely. Perhaps at the end of this excellent meeting more questions were raised than answered, which will stimulate future research. However, what became clear is that the nuclear envelope is a cellular structure with critical functions in addition to its traditional role as a barrier separating the nuclear and cytoplasmic compartments in interphase eukaryotic cells.

  10. Envelope proteins of bovine herpesvirus 1: immunological and biochemical studies

    International Nuclear Information System (INIS)

    Rodriguez Roque, L.L.

    1986-01-01

    The authors studied immunological and biochemical properties of the bovid herpesvirus 1 (BHV-1) envelope proteins in order to understand the pathogenesis of BHV-1 infection and to provide basic information for the production of effective subunit vaccines against BHV-1. Ten glycoproteins MW 180, 150, 130, 115, 97, 77, 74, 64, 55, and 45 kilodaltons (K), and a single non-glycosylated 108 K protein were quantitatively removed from purified BHV-1 virions by detergent treatment. These glycoproteins were present on the virion envelope and on the surface of BHV-1 infected cells. The quantitative removal from virions by treatment with nonionic detergents and their presence on the surface of infected cells indicate that 180/97, 150/77, and 130/74/55 K are major components of the BHV-1 envelope and are also the targets of virus neutralizing humoral immune response. Envelope glycoproteins of herpes simplex type 1 (HSV-1) bind immunoglobulin by the Fc end and it is suggested this may increase pathogenicity of this virus. They searched for a similar function in BVH-1 by measuring the ability of BHV-1 infected cells and viral envelope proteins to bind radiolabelled rabbit and bovine IgG. Binding activity for rabbit IgG or bovine IgG-Fc could not be demonstrated by BHV-1 infected MDBK cells, whereas, MDBK cells infected with HSV-1 bound rabbit IgG and bovine IgG-Fc. None of the three major envelope proteins of BHV-1 bound to rabbit or bovine IgG. The results of this study indicate that BHV-1, unlike some other herpesviruses, lack Fc binding activity

  11. The limits to biocatalysis: pushing the envelope.

    Science.gov (United States)

    Sheldon, Roger A; Brady, Dean

    2018-06-12

    In the period 1985 to 1995 applications of biocatalysis, driven by the need for more sustainable manufacture of chemicals and catalytic, (enantio)selective methods for the synthesis of pharmaceutical intermediates, largely involved the available hydrolases. This was followed, in the next two decades, by revolutionary developments in protein engineering and directed evolution for the optimisation of enzyme function and performance that totally changed the biocatalysis landscape. In the same period, metabolic engineering and synthetic biology revolutionised the use of whole cell biocatalysis in the synthesis of commodity chemicals by fermentation. In particular, developments in the enzymatic enantioselective synthesis of chiral alcohols and amines are highlighted. Progress in enzyme immobilisation facilitated applications under harsh industrial conditions, such as in organic solvents. The emergence of biocatalytic or chemoenzymatic cascade processes, often with co-immobilised enzymes, has enabled telescoping of multi-step processes. Discovering and inventing new biocatalytic processes, based on (meta)genomic sequencing, evolving enzyme promiscuity, chemomimetic biocatalysis, artificial metalloenzymes, and the introduction of non-canonical amino acids into proteins, are pushing back the limits of biocatalysis function. Finally, the integral role of biocatalysis in developing a biobased carbon-neutral economy is discussed.

  12. Quantifying seasonal velocity at Khumbu Glacier, Nepal

    Science.gov (United States)

    Miles, E.; Quincey, D. J.; Miles, K.; Hubbard, B. P.; Rowan, A. V.

    2017-12-01

    While the low-gradient debris-covered tongues of many Himalayan glaciers exhibit low surface velocities, quantifying ice flow and its variation through time remains a key challenge for studies aimed at determining the long-term evolution of these glaciers. Recent work has suggested that glaciers in the Everest region of Nepal may show seasonal variability in surface velocity, with ice flow peaking during the summer as monsoon precipitation provides hydrological inputs and thus drives changes in subglacial drainage efficiency. However, satellite and aerial observations of glacier velocity during the monsoon are greatly limited due to cloud cover. Those that do exist do not span the period over which the most dynamic changes occur, and consequently short-term (i.e. daily) changes in flow, as well as the evolution of ice dynamics through the monsoon period, remain poorly understood. In this study, we combine field and remote (satellite image) observations to create a multi-temporal, 3D synthesis of ice deformation rates at Khumbu Glacier, Nepal, focused on the 2017 monsoon period. We first determine net annual and seasonal surface displacements for the whole glacier based on Landsat-8 (OLI) panchromatic data (15m) processed with ImGRAFT. We integrate inclinometer observations from three boreholes drilled by the EverDrill project to determine cumulative deformation at depth, providing a 3D perspective and enabling us to assess the role of basal sliding at each site. We additionally analyze high-frequency on-glacier L1 GNSS data from three sites to characterize variability within surface deformation at sub-seasonal timescales. Finally, each dataset is validated against repeat-dGPS observations at gridded points in the vicinity of the boreholes and GNSS dataloggers. These datasets complement one another to infer thermal regime across the debris-covered ablation area of the glacier, and emphasize the seasonal and spatial variability of ice deformation for glaciers in High

  13. Control rod velocity limiter

    International Nuclear Information System (INIS)

    Cearley, J.E.; Carruth, J.C.; Dixon, R.C.; Spencer, S.S.; Zuloaga, J.A. Jr.

    1986-01-01

    This patent describes a velocity control arrangement for a reciprocable, vertically oriented control rod for use in a nuclear reactor in a fluid medium, the control rod including a drive hub secured to and extending from one end therefrom. The control device comprises: a toroidally shaped control member spaced from and coaxially positioned around the hub and secured thereto by a plurality of spaced radial webs thereby providing an annular passage for fluid intermediate the hub and the toroidal member spaced therefrom in coaxial position. The side of the control member toward the control rod has a smooth generally conical surface. The side of the control member away from the control rod is formed with a concave surface constituting a single annular groove. The device also comprises inner and outer annular vanes radially spaced from one another and spaced from the side of the control member away from the control rod and positioned coaxially around and spaced from the hub and secured thereto by spaced radial webs thereby providing an annular passage for fluid intermediate the hub and the vanes. The vanes are angled toward the control member, the outer edge of the inner vane being closer to the control member and the inner edge of the outer vane being closer to the control member. When the control rod moves in the fluid in the direction toward the drive hub the vanes direct a flow of fluid turbulence which provides greater resistance to movement of the control rod in the direction toward the drive hub than in the other direction

  14. Enveloping algebras of Lie groups with descrete series

    International Nuclear Information System (INIS)

    Nguyen huu Anh; Vuong manh Son

    1990-09-01

    In this article we shall prove that the enveloping algebra of the Lie algebra of some unimodular Lie group having discrete series, when localized at some element of the center, is isomorphic to the tensor product of a Weyl algebra over the ring of Laurent polynomials of one variable and the enveloping algebra of some reductive Lie algebra. In particular, it will be proved that the Lie algebra of a unimodular solvable Lie group having discrete series satisfies the Gelfand-Kirillov conjecture. (author). 6 refs

  15. Constant envelope OFDM scheme for 6PolSK-QPSK

    Science.gov (United States)

    Li, Yupeng; Ding, Ding

    2018-03-01

    A constant envelope OFDM scheme with phase modulator (PM-CE-OFDM) for 6PolSK-QPSK modulation was demonstrated. Performance under large fiber launch power is measured to check its advantages in counteracting fiber nonlinear impairments. In our simulation, PM-CE-OFDM, RF-assisted constant envelope OFDM (RF-CE-OFDM) and conventional OFDM (Con-OFDM) are transmitted through 80 km standard single mode fiber (SSMF) single channel and WDM system. Simulation results confirm that PM-CE-OFDM has best performance in resisting fiber nonlinearity. In addition, benefiting from the simple system structure, the complexity and cost of PM-CE-OFDM system could be reduced effectively.

  16. Data Envelopment Analysis (DEA) Model in Operation Management

    Science.gov (United States)

    Malik, Meilisa; Efendi, Syahril; Zarlis, Muhammad

    2018-01-01

    Quality management is an effective system in operation management to develops, maintains, and improves quality from groups of companies that allow marketing, production, and service at the most economycal level as well as ensuring customer satisfication. Many companies are practicing quality management to improve their bussiness performance. One of performance measurement is through measurement of efficiency. One of the tools can be used to assess efficiency of companies performance is Data Envelopment Analysis (DEA). The aim of this paper is using Data Envelopment Analysis (DEA) model to assess efficiency of quality management. In this paper will be explained CCR, BCC, and SBM models to assess efficiency of quality management.

  17. Asymmetry of the envelope of supernova 1987A

    Energy Technology Data Exchange (ETDEWEB)

    Papaliolios, C.; Karovska, M.; Koechlin, L.; Nisenson, P.; Standley, C.; Heathcote, S.

    1989-04-13

    The supernova SN1987A in the Large Magellanic Cloud has been observed by high-angular-resolution speckle interferometry since 25 March (30 days after the explosion) with the 4-m telescope at the Cerro Tololo Interamerican Observatory. Data obtained on 25 March and 2 April 1987 revealed a second bright 'companion' source separated from the supernova by 60 milliarcseconds and less than three magnitudes fainter than the supernova. Measurements of the average diameter of the supernova envelope have been made from data recorded from March 1987 to April 1988. Here we present a more detailed analysis of these data, which shows that the expanding envelope is asymmetric. (author).

  18. Asymmetry of the envelope of supernova 1987A

    International Nuclear Information System (INIS)

    Papaliolios, C.; Karovska, M.; Koechlin, L.; Nisenson, P.; Standley, C.; Heathcote, S.

    1989-01-01

    The supernova SN1987A in the Large Magellanic Cloud has been observed by high-angular-resolution speckle interferometry since 25 March (30 days after the explosion) with the 4-m telescope at the Cerro Tololo Interamerican Observatory. Data obtained on 25 March and 2 April 1987 revealed a second bright 'companion' source separated from the supernova by 60 milliarcseconds and less than three magnitudes fainter than the supernova. Measurements of the average diameter of the supernova envelope have been made from data recorded from March 1987 to April 1988. Here we present a more detailed analysis of these data, which shows that the expanding envelope is asymmetric. (author)

  19. Calculation of CWKB envelope in boson and fermion productions

    International Nuclear Information System (INIS)

    Biswas, S.; Chowdhury, I.

    2007-01-01

    We present the calculation of envelope of boson and of both low-and high-mass fermion production at the end of inflation when the coherently oscillating inflations decay into bosons and fermions. We consider three different models of inflation and use CWKB technique to calculate the envelope to understand the structure of resonance band formation. We observe that though low-mass fermion production is not effective in preheating because of Pauli blocking, it is quite probable for high-mass fermion to take part in pre heating. (author)

  20. Velocity Dispersions Across Bulge Types

    International Nuclear Information System (INIS)

    Fabricius, Maximilian; Bender, Ralf; Hopp, Ulrich; Saglia, Roberto; Drory, Niv; Fisher, David

    2010-01-01

    We present first results from a long-slit spectroscopic survey of bulge kinematics in local spiral galaxies. Our optical spectra were obtained at the Hobby-Eberly Telescope with the LRS spectrograph and have a velocity resolution of 45 km/s (σ*), which allows us to resolve the velocity dispersions in the bulge regions of most objects in our sample. We find that the velocity dispersion profiles in morphological classical bulge galaxies are always centrally peaked while the velocity dispersion of morphologically disk-like bulges stays relatively flat towards the center--once strongly barred galaxies are discarded.

  1. On linear relationship between shock velocity and particle velocity

    International Nuclear Information System (INIS)

    Dandache, H.

    1986-11-01

    We attempt to derive the linear relationship between shock velocity U s and particle velocity U p from thermodynamic considerations, taking into account an ideal gas equation of state and a Mie-Grueneisen equation of state for solids. 23 refs

  2. ENVIRONMENT AND PROTOSTELLAR EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yichen [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Tan, Jonathan C., E-mail: yczhang.astro@gmail.com [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States)

    2015-04-01

    Even today in our Galaxy, stars form from gas cores in a variety of environments, which may affect the properties of the resulting star and planetary systems. Here, we study the role of pressure, parameterized via ambient clump mass surface density, on protostellar evolution and appearance, focusing on low-mass Sun-like stars and considering a range of conditions from relatively low pressure filaments in Taurus, to intermediate pressures of cluster-forming clumps like the Orion Nebula Cluster, to very high pressures that may be found in the densest infrared dark clouds or in the Galactic center. We present unified analytic and numerical models for the collapse of prestellar cores, accretion disks, protostellar evolution, and bipolar outflows, coupled with radiative transfer calculations and a simple astrochemical model to predict CO gas-phase abundances. Prestellar cores in high-pressure environments are smaller and denser and thus collapse with higher accretion rates and efficiencies, resulting in higher luminosity protostars with more powerful outflows. The protostellar envelope is heated to warmer temperatures, affecting infrared morphologies (and thus classification) and astrochemical processes like CO depletion onto dust grain ice mantles (and thus CO morphologies). These results have general implications for star and planet formation, especially via their effect on astrochemical and dust grain evolution during infall to and through protostellar accretion disks.

  3. Sodium Velocity Maps on Mercury

    Science.gov (United States)

    Potter, A. E.; Killen, R. M.

    2011-01-01

    The objective of the current work was to measure two-dimensional maps of sodium velocities on the Mercury surface and examine the maps for evidence of sources or sinks of sodium on the surface. The McMath-Pierce Solar Telescope and the Stellar Spectrograph were used to measure Mercury spectra that were sampled at 7 milliAngstrom intervals. Observations were made each day during the period October 5-9, 2010. The dawn terminator was in view during that time. The velocity shift of the centroid of the Mercury emission line was measured relative to the solar sodium Fraunhofer line corrected for radial velocity of the Earth. The difference between the observed and calculated velocity shift was taken to be the velocity vector of the sodium relative to Earth. For each position of the spectrograph slit, a line of velocities across the planet was measured. Then, the spectrograph slit was stepped over the surface of Mercury at 1 arc second intervals. The position of Mercury was stabilized by an adaptive optics system. The collection of lines were assembled into an images of surface reflection, sodium emission intensities, and Earthward velocities over the surface of Mercury. The velocity map shows patches of higher velocity in the southern hemisphere, suggesting the existence of sodium sources there. The peak earthward velocity occurs in the equatorial region, and extends to the terminator. Since this was a dawn terminator, this might be an indication of dawn evaporation of sodium. Leblanc et al. (2008) have published a velocity map that is similar.

  4. Introduction to vector velocity imaging

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Udesen, Jesper; Hansen, Kristoffer Lindskov

    Current ultrasound scanners can only estimate the velocity along the ultrasound beam and this gives rise to the cos() factor on all velocity estimates. This is a major limitation as most vessels are close to perpendicular to the beam. Also the angle varies as a function of space and time making ...

  5. Enveloped virus-like particles as vaccines against pathogenic arboviruses

    NARCIS (Netherlands)

    Pijlman, G.P.

    2015-01-01

    Arthropod-borne arboviruses form a continuous threat to human and animal health, but few arboviral vaccines are currently available. Advances in expression technology for complex, enveloped virus-like particles (eVLPs) create new opportunities to develop potent vaccines against pathogenic

  6. Measuring Eco-efficiency of Production with Data Envelopment Analysis

    NARCIS (Netherlands)

    Kuosmanen, T.K.; Kortelainen, M.

    2005-01-01

    Aggregation of environmental pressures into a single environmental damage index is a major challenge of eco-efficiency measurement. This article examines how the data envelopment analysis (DEA) method can be adapted for this purpose. DEA accounts for substitution possibilities between different

  7. Modeling of heat and mass transfer in lateritic building envelopes

    International Nuclear Information System (INIS)

    Meukam, Pierre

    2004-10-01

    The aim of the present work is to investigate the behavior of building envelopes made of local lateritic soil bricks subjected to different climatic conditions. The analysis is developed for the prediction of the temperature, relative humidity and water content behavior within the walls. The building envelopes studied in this work consist of lateritic soil bricks with incorporation of natural pozzolan or sawdust in order to obtain small thermal conductivity and low-density materials, and limit the heat transfer between the atmospheric climate and the inside environment. In order to describe coupled heat and moisture transfer in wet porous materials, the coupled equations were solved by the introduction of diffusion coefficients. A numerical model HMtrans, developed for prediction of beat and moisture transfer in multi-layered building components, was used to simulate the temperature, water content and relative humidity profiles within the building envelopes. The results allow the prediction of the duration of the exposed building walls to the local weather conditions. They show that for any of three climatic conditions considered, relative humidity and water content do not exceed 87% and 5% respectively. There is therefore minimum possibility of water condensation in the materials studied. The durability of building envelopes made of lateritic soil bricks with incorporation of natural pozzolan or sawdust is not strongly affected by the climatic conditions in tropical and equatorial regions. (author)

  8. Design of a Haptic Feedback System for Flight Envelope Protection

    NARCIS (Netherlands)

    Van Baelen, D.; Ellerbroek, J.; van Paassen, M.M.; Mulder, M.

    2018-01-01

    Current Airbus aircraft use a fly-by-wire control device: a passive spring-damper system which generates, without any force feedback, an electrical signal to the flight control computer. Additionally, a hard flight envelope protection system is used which can limit the inputs of the pilot when

  9. Hygrothermal Simulation: A Tool for Building Envelope Design Analysis

    Science.gov (United States)

    Samuel V. Glass; Anton TenWolde; Samuel L. Zelinka

    2013-01-01

    Is it possible to gauge the risk of moisture problems while designing the building envelope? This article provides a brief introduction to computer-based hygrothermal (heat and moisture) simulation, shows how simulation can be useful as a design tool, and points out a number of im-portant considerations regarding model inputs and limita-tions. Hygrothermal simulation...

  10. Spectral Envelopes and Additive + Residual Analysis/Synthesis

    Science.gov (United States)

    Rodet, Xavier; Schwarz, Diemo

    The subject of this chapter is the estimation, representation, modification, and use of spectral envelopes in the context of sinusoidal-additive-plus-residual analysis/synthesis. A spectral envelope is an amplitude-vs-frequency function, which may be obtained from the envelope of a short-time spectrum (Rodet et al., 1987; Schwarz, 1998). [Precise definitions of such an envelope and short-time spectrum (STS) are given in Section 2.] The additive-plus-residual analysis/synthesis method is based on a representation of signals in terms of a sum of time-varying sinusoids and of a non-sinusoidal residual signal [e.g., see Serra (1989), Laroche et al. (1993), McAulay and Quatieri (1995), and Ding and Qian (1997)]. Many musical sound signals may be described as a combination of a nearly periodic waveform and colored noise. The nearly periodic part of the signal can be viewed as a sum of sinusoidal components, called partials, with time-varying frequency and amplitude. Such sinusoidal components are easily observed on a spectral analysis display (Fig. 5.1) as obtained, for instance, from a discrete Fourier transform.

  11. A model for the sustainable selection of building envelope assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Huedo, Patricia, E-mail: huedo@uji.es [Universitat Jaume I (Spain); Mulet, Elena, E-mail: emulet@uji.es [Universitat Jaume I (Spain); López-Mesa, Belinda, E-mail: belinda@unizar.es [Universidad de Zaragoza (Spain)

    2016-02-15

    The aim of this article is to define an evaluation model for the environmental impacts of building envelopes to support planners in the early phases of materials selection. The model is intended to estimate environmental impacts for different combinations of building envelope assemblies based on scientifically recognised sustainability indicators. These indicators will increase the amount of information that existing catalogues show to support planners in the selection of building assemblies. To define the model, first the environmental indicators were selected based on the specific aims of the intended sustainability assessment. Then, a simplified LCA methodology was developed to estimate the impacts applicable to three types of dwellings considering different envelope assemblies, building orientations and climate zones. This methodology takes into account the manufacturing, installation, maintenance and use phases of the building. Finally, the model was validated and a matrix in Excel was created as implementation of the model. - Highlights: • Method to assess the envelope impacts based on a simplified LCA • To be used at an earlier phase than the existing methods in a simple way. • It assigns a score by means of known sustainability indicators. • It estimates data about the embodied and operating environmental impacts. • It compares the investment costs with the costs of the consumed energy.

  12. CONTROL OF INDOOR ENVIRONMENTS VIA THE REGULATION OF BUILDING ENVELOPES

    Directory of Open Access Journals (Sweden)

    Mitja Košir

    2011-01-01

    Full Text Available The design of comfortable, healthy and stimulating indoor environments in buildings has a direct impact on the users and on energy consumption, as well as on the wider soci-economic environment of society.The indoor environment of buildings is defined with the formulation of the building envelope, which functions as an interface between the internal and external environments and its users. A properly designed, flexible and adequately controlled building envelope is a starting point in the formulation of a high-quality indoor environment. The systematic treatment of the indoor environment and building envelope from a user’s point of view represents an engineering approach that enables the holistic treatment of buildings, as well as integrated components and systems. The presented division of indoor environment in terms of visual, thermal, olfactory, acoustic and ergonomic sub-environments enables the classification and selection of crucial factors influencing design. This selection and classification can be implemented in the design, as well as in control applications of the building envelope. The implementation of the approach described is demonstrated with an example of an automated control system for the internal environment of an office in the building of the Faculty of Civil and Geodetic Engineering.

  13. A model for the sustainable selection of building envelope assemblies

    International Nuclear Information System (INIS)

    Huedo, Patricia; Mulet, Elena; López-Mesa, Belinda

    2016-01-01

    The aim of this article is to define an evaluation model for the environmental impacts of building envelopes to support planners in the early phases of materials selection. The model is intended to estimate environmental impacts for different combinations of building envelope assemblies based on scientifically recognised sustainability indicators. These indicators will increase the amount of information that existing catalogues show to support planners in the selection of building assemblies. To define the model, first the environmental indicators were selected based on the specific aims of the intended sustainability assessment. Then, a simplified LCA methodology was developed to estimate the impacts applicable to three types of dwellings considering different envelope assemblies, building orientations and climate zones. This methodology takes into account the manufacturing, installation, maintenance and use phases of the building. Finally, the model was validated and a matrix in Excel was created as implementation of the model. - Highlights: • Method to assess the envelope impacts based on a simplified LCA • To be used at an earlier phase than the existing methods in a simple way. • It assigns a score by means of known sustainability indicators. • It estimates data about the embodied and operating environmental impacts. • It compares the investment costs with the costs of the consumed energy.

  14. Print and supply of envelopes and file covers

    Indian Academy of Sciences (India)

    “Tender for Supply of Printed Envelopes and File Covers". Tender ... Twenty Five Thousand Only) in the form of Demand Draft drawn on any Nationalized. Bank and .... m) The finalized contract shall be interpreted under Indian Laws. In case of ...

  15. Envelopes of Sets of Measures, Tightness, and Markov Control Processes

    International Nuclear Information System (INIS)

    Gonzalez-Hernandez, J.; Hernandez-Lerma, O.

    1999-01-01

    We introduce upper and lower envelopes for sets of measures on an arbitrary topological space, which are then used to give a tightness criterion. These concepts are applied to show the existence of optimal policies for a class of Markov control processes

  16. Development of a pneumatic roof envelope for industrial greenhouses

    NARCIS (Netherlands)

    Lindner, G.; Vos, de G.J.

    2008-01-01

    The Eindhoven University of Technology (TU/e) was approached by Van Diemen BV, a turn-key greenhouse builder looking for a new and higher insulated design for their green house envelope. They had developed a new system of climate control which rendered windows for ventilation purposes unnecessary

  17. The potential of building envelope greening to achieve quietness

    NARCIS (Netherlands)

    Van Renterghem, T.; Hornikx, M.C.J.; Forssén, J.; Botteldooren, D.

    2013-01-01

    Reduction of noise is one of the multiple benefits of building envelope greening measures. The potential of wall vegetation systems, green roofs, vegetated low screens at roof edges, and also combinations of such treatments, have been studied by means of combining 2D and 3D full-wave numerical

  18. Bioinformatics Analysis of Envelope Glycoprotein E epitopes of ...

    African Journals Online (AJOL)

    The E glycoprotein of dengue virus is responsible for the viral binding to the receptor. The crystal structure of envelope glycoprotein has already been determined. However, where the well-defined Bcell and T-cell epitopes are located is still a question. Because of the large variations among the four dengue genotypes, it is ...

  19. Origin of envelope proteins of a leukemia virus

    International Nuclear Information System (INIS)

    Schneider, R.P.

    1975-01-01

    The roles of avian myeloblastosis virus (AMV) and host myeloblast cells in controlling the protein composition of virus envelope and host cell membrane are being studied by examining an ATPase enzyme in the virus and cells. New culture techniques for virus producing myeloblasts have been developed. (U.S.)

  20. Enveloped virus flocculation and removal in osmolyte solutions.

    Science.gov (United States)

    Gencoglu, Maria F; Heldt, Caryn L

    2015-07-20

    Our ability to reduce infectious disease burden throughout the world has been greatly improved by the creation of vaccines. However, worldwide immunization rates are low. The two most likely reasons are the lack of sufficient distribution in underdeveloped countries and the high cost of vaccine products. The high costs are due to the difficulties of manufacturing individual vaccine products with specialized purification trains. In this study, we propose to use virus flocculation in osmolytes, followed by microfiltration, as an alternative vaccine purification operation. In our previous work, we demonstrated that osmolytes preferentially flocculate a non-enveloped virus, porcine parvovirus (PPV). In this work we show that osmolytes flocculate the enveloped virus, Sindbis virus heat resistant strain (SVHR), and demonstrate a >80% removal with a 0.2 μm microfilter membrane while leaving proteins in solution. The best osmolytes were tested for their ability to flocculate SVHR at different concentrations, pH and ionic strengths. Our best removal was 98% of SVHR in 0.3M mannitol at a pH of 5. We propose that osmolytes are able to flocculate hydrophobic non-enveloped and enveloped virus particles by the reduction of the hydration layer around the particles, which stimulates virus aggregation. Now that we have demonstrated that protecting osmolytes flocculate viruses, this method has the potential to be a future platform purification process for vaccines. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Spectral Envelope Transformation in Singing Voice for Advanced Pitch Shifting

    Directory of Open Access Journals (Sweden)

    José L. Santacruz

    2016-11-01

    Full Text Available The aim of the present work is to perform a step towards more natural pitch shifting techniques in singing voice for its application in music production and entertainment systems. In this paper, we present an advanced method to achieve natural modifications when applying a pitch shifting process to singing voice by modifying the spectral envelope of the audio excerpt. To this end, an all-pole model has been selected to model the spectral envelope, which is estimated using a constrained non-linear optimization. The analysis of the global variations of the spectral envelope was carried out by identifying changes of the parameters of the model along with the changes of the pitch. With the obtained spectral envelope transformation functions, we applied our pitch shifting scheme to some sustained vowels in order to compare results with the same transformation made by using the Flex Pitch plugin of Logic Pro X and pitch synchronous overlap and add technique (PSOLA. This comparison has been carried out by means of both an objective and a subjective evaluation. The latter was done with a survey open to volunteers on our website.

  2. Masking Release for Sweeping Masker Components with Correlated Envelopes

    DEFF Research Database (Denmark)

    Verhey, Jesko l.; Klein-Hennig, Hendrike; Epp, Bastian

    2013-01-01

    To separate sounds from different sound sources, common properties of natural sounds are used by the auditory system, such as coherent temporal envelope fluctuations and correlated changes of frequency in different frequency regions. The present study investigates how the auditory systemprocesses...

  3. Innovative Danish Building Envelope Components for Passive Houses

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Svendsen, Svend

    2006-01-01

    and in some cases very innovative envelope constructions. In this paper, two of the most interesting components are described; a prefabricated light-weight exterior wall element with a load-bearing plywood and steel frame and a foundation / slab on ground solution based on concrete and EPS insulation...

  4. Purification and characterization of cell-envelope proteinase from ...

    African Journals Online (AJOL)

    user

    2012-10-18

    Oct 18, 2012 ... phenylmethylsulfonyl fluoride;. ACE, angiotensin-I-converting enzyme. Poolman, 1998). Cell-envelope proteinase (CEP) play an important role in the lactobacillus proteolytic system. CEPs are the critical enzyme in the system (Kunji et al., 1996), since it is the only enzyme that can initiate the breakdown of.

  5. Subphotospheric fluctuations in magnetized radiative envelopes: contribution from unstable magnetosonic waves

    Science.gov (United States)

    Sen, Koushik; Fernández, Rodrigo; Socrates, Aristotle

    2018-06-01

    We examine the excitation of unstable magnetosonic waves in the radiative envelopes of intermediate- and high-mass stars with a magnetic field of ˜kG strength. Wind clumping close to the star and microturbulence can often be accounted for when including small-scale, subphotospheric density or velocity perturbations. Compressional waves - with wavelengths comparable to or shorter than the gas pressure scale height - can be destabilized by the radiative flux in optically thick media when a magnetic field is present, in a process called the radiation-driven magneto-acoustic instability (RMI). The instability does not require radiation or magnetic pressure to dominate over gas pressure, and acts independently of subsurface convection zones. Here we evaluate the conditions for the RMI to operate on a grid of stellar models covering a mass range 3-40 M⊙ at solar metallicity. For a uniform 1 kG magnetic field, fast magnetosonic modes are unstable down to an optical depth of a few tens, while unstable slow modes extend beyond the depth of the iron convection zone. The qualitative behaviour is robust to magnetic field strength variations by a factor of a few. When combining our findings with previous results for the saturation amplitude of the RMI, we predict velocity fluctuations in the range ˜0.1-10 km s-1. These amplitudes are a monotonically increasing function of the ratio of radiation to gas pressure, or alternatively, of the zero-age main sequence mass.

  6. Binary evolution and observational constraints

    International Nuclear Information System (INIS)

    Loore, C. de

    1984-01-01

    The evolution of close binaries is discussed in connection with problems concerning mass and angular momentum losses. Theoretical and observational evidence for outflow of matter, leaving the system during evolution is given: statistics on total masses and mass ratios, effects of the accretion of the mass gaining component, the presence of streams, disks, rings, circumstellar envelopes, period changes, abundance changes in the atmosphere. The effects of outflowing matter on the evolution is outlined, and estimates of the fraction of matter expelled by the loser, and leaving the system, are given. The various time scales involved with evolution and observation are compared. Examples of non conservative evolution are discussed. Problems related to contact phases, on mass and energy losses, in connection with entropy changes are briefly analysed. For advanced stages the disruption probabilities for supernova explosions are examined. A global picture is given for the evolution of massive close binaries, from ZAMS, through WR phases, X-ray phases, leading to runaway pulsars or to a binary pulsar and later to a millisecond pulsar. (Auth.)

  7. Diffraction imaging and velocity analysis using oriented velocity continuation

    KAUST Repository

    Decker, Luke

    2014-08-05

    We perform seismic diffraction imaging and velocity analysis by separating diffractions from specular reflections and decomposing them into slope components. We image slope components using extrapolation in migration velocity in time-space-slope coordinates. The extrapolation is described by a convection-type partial differential equation and implemented efficiently in the Fourier domain. Synthetic and field data experiments show that the proposed algorithm is able to detect accurate time-migration velocities by automatically measuring the flatness of events in dip-angle gathers.

  8. Amphibious Shear Velocity Structure of the Cascadia Subduction Zone

    Science.gov (United States)

    Janiszewski, H. A.; Gaherty, J. B.; Abers, G. A.; Gao, H.

    2017-12-01

    The amphibious Cascadia Initiative crosses the coastline of the Cascadia subduction zone (CSZ) deploying seismometers from the Juan de Fuca ridge offshore to beyond the volcanic arc onshore. This allows unprecedented seismic imaging of the CSZ, enabling examination of both the evolution of the Juan de Fuca plate prior to and during subduction as well as the along strike variability of the subduction system. Here we present new results from an amphibious shear velocity model for the crust and upper mantle across the Cascadia subduction zone. The primary data used in this inversion are surface-wave phase velocities derived from ambient-noise Rayleigh-wave data in the 10 - 20 s period band, and teleseismic earthquake Rayleigh wave phase velocities in the 20 - 160 s period band. Phase velocity maps from these data reflect major tectonic structures including the transition from oceanic to continental lithosphere, Juan de Fuca lithosphere that is faster than observations in the Pacific for oceanic crust of its age, slow velocities associated with the accretionary prism, the front of the fast subducting slab, and the Cascades volcanic arc which is associated with slower velocities in the south than in the north. Crustal structures are constrained by receiver functions in the offshore forearc and onshore regions, and by active source constraints on the Juan de Fuca plate prior to subduction. The shear-wave velocities are interpreted in their relationships to temperature, presence of melt or hydrous alteration, and compositional variation of the CSZ.

  9. The psychic envelopes in psychoanalytic theories of infancy.

    Directory of Open Access Journals (Sweden)

    Denis eMellier

    2014-07-01

    Full Text Available This paper aims to review the topic of psychic envelopes and to sketch the main outlines of this concept in infancy. We first explore the origins of the concept in Freud's 'protective shield' and then its development in adult psychoanalysis before going on to see how this fits in infancy with post-Bionian psychoanalysis and development. Four central notions guide this review:1 Freud's protective shield describes a barrier to protect the psychic apparatus against potentially overflowing trauma. It is a core notion which highlights a serious clinical challenge for patients for whom the shield is damaged or faulty: the risk of confusion of borders between the internal/external world, conscious/unconscious, mind/body, or self-conservation/sexuality.2 Anzieu's Skin-Ego is defined by the different senses of the body. The different layers of experienced sensation, of this body-ego, go on to form the psychic envelope. This theory contributes to our understanding of how early trauma, due to the failures of maternal care, can continue to have an impact in adult life. 3 Bick's psychic skin establishes the concept in relation to infancy. The mother’s containing functions allow a first psychic skin to develop, which then defines an infant’s psychic space and affords the infant a degree of self-containment. Houzel then conceptualized this process as a stabilization of drive forces.4 Stern's narrative envelope derives from the intersection between psychoanalysis and neuroscience. It gives us another way to conceptualise the development of pre-verbal communication. It may also pave the way for a finer distinction of different types of envelopes.Ultimately, in this review we find that psychic envelopes in infancy can be viewed from four different perspectives (economic, topographical, dynamic and genetic and recommend further investigation.

  10. Friction properties and deformation mechanisms of halite(-mica) gouges from low to high sliding velocities

    NARCIS (Netherlands)

    Buijze, L.; Niemeijer, A.R.; Han, R.; Shimamoto, T.; Spiers, C.J.

    2017-01-01

    The evolution of friction as a function of slip rate is important in understanding earthquake nucleation and propagation. Many laboratory experiments investigating friction of fault rocks are either conducted in the low velocity regime (10−8–10−4 ms−1) or in the high velocity regime (0.01–1 m s−1).

  11. A stochastic differential equation framework for the timewise dynamics of turbulent velocities

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Schmiegel, Jürgen

    2008-01-01

    We discuss a stochastic differential equation as a modeling framework for the timewise dynamics of turbulent velocities. The equation is capable of capturing basic stylized facts of the statistics of temporal velocity increments. In particular, we focus on the evolution of the probability density...

  12. RADIAL VELOCITY MONITORING OF KEPLER HEARTBEAT STARS

    Energy Technology Data Exchange (ETDEWEB)

    Shporer, Avi [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Fuller, Jim [TAPIR, Walter Burke Institute for Theoretical Physics, Mailcode 350-17, Caltech, Pasadena, CA 91125 (United States); Isaacson, Howard [Department of Astronomy, University of California, Berkeley CA 94720 (United States); Hambleton, Kelly; Prša, Andrej [Department of Astrophysics and Planetary Science, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 (United States); Thompson, Susan E. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Kurtz, Donald W. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE (United Kingdom); Howard, Andrew W. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); O’Leary, Ryan M. [JILA, University of Colorado and NIST, 440 UCB, Boulder, 80309-0440 (United States)

    2016-09-20

    Heartbeat stars (HB stars) are a class of eccentric binary stars with close periastron passages. The characteristic photometric HB signal evident in their light curves is produced by a combination of tidal distortion, heating, and Doppler boosting near orbital periastron. Many HB stars continue to oscillate after periastron and along the entire orbit, indicative of the tidal excitation of oscillation modes within one or both stars. These systems are among the most eccentric binaries known, and they constitute astrophysical laboratories for the study of tidal effects. We have undertaken a radial velocity (RV) monitoring campaign of Kepler HB stars in order to measure their orbits. We present our first results here, including a sample of 22 Kepler HB systems, where for 19 of them we obtained the Keplerian orbit and for 3 other systems we did not detect a statistically significant RV variability. Results presented here are based on 218 spectra obtained with the Keck/HIRES spectrograph during the 2015 Kepler observing season, and they have allowed us to obtain the largest sample of HB stars with orbits measured using a single instrument, which roughly doubles the number of HB stars with an RV measured orbit. The 19 systems measured here have orbital periods from 7 to 90 days and eccentricities from 0.2 to 0.9. We show that HB stars draw the upper envelope of the eccentricity–period distribution. Therefore, HB stars likely represent a population of stars currently undergoing high eccentricity migration via tidal orbital circularization, and they will allow for new tests of high eccentricity migration theories.

  13. RADIAL VELOCITY MONITORING OF KEPLER HEARTBEAT STARS

    International Nuclear Information System (INIS)

    Shporer, Avi; Fuller, Jim; Isaacson, Howard; Hambleton, Kelly; Prša, Andrej; Thompson, Susan E.; Kurtz, Donald W.; Howard, Andrew W.; O’Leary, Ryan M.

    2016-01-01

    Heartbeat stars (HB stars) are a class of eccentric binary stars with close periastron passages. The characteristic photometric HB signal evident in their light curves is produced by a combination of tidal distortion, heating, and Doppler boosting near orbital periastron. Many HB stars continue to oscillate after periastron and along the entire orbit, indicative of the tidal excitation of oscillation modes within one or both stars. These systems are among the most eccentric binaries known, and they constitute astrophysical laboratories for the study of tidal effects. We have undertaken a radial velocity (RV) monitoring campaign of Kepler HB stars in order to measure their orbits. We present our first results here, including a sample of 22 Kepler HB systems, where for 19 of them we obtained the Keplerian orbit and for 3 other systems we did not detect a statistically significant RV variability. Results presented here are based on 218 spectra obtained with the Keck/HIRES spectrograph during the 2015 Kepler observing season, and they have allowed us to obtain the largest sample of HB stars with orbits measured using a single instrument, which roughly doubles the number of HB stars with an RV measured orbit. The 19 systems measured here have orbital periods from 7 to 90 days and eccentricities from 0.2 to 0.9. We show that HB stars draw the upper envelope of the eccentricity–period distribution. Therefore, HB stars likely represent a population of stars currently undergoing high eccentricity migration via tidal orbital circularization, and they will allow for new tests of high eccentricity migration theories.

  14. Radial velocity asymmetries from jets with variable velocity profiles

    International Nuclear Information System (INIS)

    Cerqueira, A. H.; Vasconcelos, M. J.; Velazquez, P. F.; Raga, A. C.; De Colle, F.

    2006-01-01

    We have computed a set of 3-D numerical simulations of radiatively cooling jets including variabilities in both the ejection direction (precession) and the jet velocity (intermittence), using the Yguazu-a code. In order to investigate the effects of jet rotation on the shape of the line profiles, we also introduce an initial toroidal rotation velocity profile. Since the Yguazu-a code includes an atomic/ionic network, we are able to compute the emission coefficients for several emission lines, and we generate line profiles for the Hα, [O I]λ6300, [S II]λ6716 and [N II]λ6548 lines. Using initial parameters that are suitable for the DG Tau microjet, we show that the computed radial velocity shift for the medium-velocity component of the line profile as a function of distance from the jet axis is strikingly similar for rotating and non-rotating jet models

  15. THE EVOLUTION OF THE KINEMATICS OF NEBULAR SHELLS IN PLANETARY NEBULAE IN THE MILKY WAY BULGE

    International Nuclear Information System (INIS)

    Richer, Michael G.; Lopez, Jose Alberto; Garcia-Diaz, Maria Teresa; Clark, David M.; Pereyra, Margarita; Diaz-Mendez, Enrique

    2010-01-01

    We study the line widths in the [O III]λ5007 and Hα lines for two groups of planetary nebulae in the Milky Way bulge based upon spectroscopy obtained at the Observatorio Astronomico Nacional in the Sierra San Pedro Martir (OAN-SPM) using the Manchester Echelle Spectrograph. The first sample includes objects early in their evolution, having high Hβ luminosities, but [O III]λ5007/Hβ 0.5. These planetary nebulae represent evolutionary phases preceding and following those of the objects studied by Richer et al. in 2008. Our sample of planetary nebulae with weak [O III]λ5007 has a line width distribution similar to that of the expansion velocities of the envelopes of asymptotic giant branch stars and shifted to systematically lower values as compared to the less evolved objects studied by Richer et al. The sample with strong He II λ4686 has a line width distribution indistinguishable from that of the more evolved objects from Richer et al., but a distribution in angular size that is systematically larger and so they are clearly more evolved. These data and those of Richer et al. form a homogeneous sample from a single Galactic population of planetary nebulae, from the earliest evolutionary stages until the cessation of nuclear burning in the central star. They confirm the long-standing predictions of hydrodynamical models of planetary nebulae, where the kinematics of the nebular shell are driven by the evolution of the central star.

  16. Switching from static to adaptable and dynamic building envelopes: A paradigm shift for the energy efficiency in buildings

    Directory of Open Access Journals (Sweden)

    Marco Perino

    2015-11-01

    Full Text Available The key role of the building envelope in attaining building energy efficiency and satisfactory indoor comfort has long been established. Nevertheless, until recent times, all efforts and attention have mainly been focused on increasing and optimizing the thermal insulation of the envelope components. This strategy was a winning approach for a long time, but its limitations became obvious when users and designers started to consider the overall energy demand of a building and started to aim for Zero Energy Building (ZEB or nearly ZEB goals. New and more revolutionary concepts and technologies needed to be developed to satisfy such challenging requirements. The potential benefits of this technological development are relevant since the building envelope plays a key role in controlling the energy and mass flows from outdoors to indoors (and vice versa and, moreover, the facades offer a significant opportunity for solar energy exploitation. Several researches have demonstrated that the limitation of the existing facades could be overcome only by switching from ‘static’ to ‘responsive’ and ‘dynamic’ systems, such as Multifunctional Facade Modules (MFMs and Responsive Building Elements (RBE. These components are able to continuously and pro-actively react to outdoor and indoor environment conditions and facilitate and enhance the exploitation of renewable and low exergy sources. In order to reduce the energy demand, to maximize the indoor comfort conditions and to produce energy at the site, these almost ‘self-sufficient’, or even ‘positive energy’ building skins frequently incorporate different technologies and are functionally connected to other building services and installations. An overview of the technological evolution of the building envelope that has taken place, ranging from traditional components to the innovative skins, will be given in this paper, while focusing on the different approaches that have characterized this

  17. Expansion of the HMX-1 Flight Envelope With the EDU-5/P Laser Eye Protection Spectacles

    National Research Council Canada - National Science Library

    Penhallegon, William

    2004-01-01

    The purpose of this testing was to determine if the day operations envelope should be expanded to include takeoffs and landings, whether the night operations envelope should he expanded in the VH-6ON...

  18. Topological soliton solutions for some nonlinear evolution equations

    Directory of Open Access Journals (Sweden)

    Ahmet Bekir

    2014-03-01

    Full Text Available In this paper, the topological soliton solutions of nonlinear evolution equations are obtained by the solitary wave ansatz method. Under some parameter conditions, exact solitary wave solutions are obtained. Note that it is always useful and desirable to construct exact solutions especially soliton-type (dark, bright, kink, anti-kink, etc. envelope for the understanding of most nonlinear physical phenomena.

  19. Fractals control in particle's velocity

    International Nuclear Information System (INIS)

    Zhang Yongping; Liu Shutang; Shen Shulan

    2009-01-01

    Julia set, a fractal set of the literature of nonlinear physics, has significance for the engineering applications. For example, the fractal structure characteristics of the generalized M-J set could visually reflect the change rule of particle's velocity. According to the real world requirement, the system need show various particle's velocity in some cases. Thus, the control of the nonlinear behavior, i.e., Julia set, has attracted broad attention. In this work, an auxiliary feedback control is introduced to effectively control the Julia set that visually reflects the change rule of particle's velocity. It satisfies the performance requirement of the real world problems.

  20. Southern high-velocity stars

    International Nuclear Information System (INIS)

    Augensen, H.J.; Buscombe, W.

    1978-01-01

    Using the model of the Galaxy presented by Eggen, Lynden-Bell and Sandage (1962), plane galactic orbits have been calculated for 800 southern high-velocity stars which possess parallax, proper motion, and radial velocity data. The stars with trigonometric parallaxes were selected from Buscombe and Morris (1958), supplemented by more recent spectroscopic data. Photometric parallaxes from infrared color indices were used for bright red giants studied by Eggen (1970), and for red dwarfs for which Rodgers and Eggen (1974) determined radial velocities. A color-color diagram based on published values of (U-B) and (B-V) for most of these stars is shown. (Auth.)

  1. AM Envelope. The potential of Additive Manufacturing for facade constructions

    Directory of Open Access Journals (Sweden)

    Holger Strauss

    2017-11-01

    Full Text Available This dissertation shows the potential of Additive Manufacturing (AM for the development of building envelopes: AM will change the way of designing facades, how we engineer and produce them. To achieve today’s demands from those future envelopes, we have to find new solutions. New technologies offer one possible way to do so. They open new approaches in designing, producing and processing building construction and facades. Finding the one capable of having big impact is difficult – Additive Manufacturing is one possible answer. The term ‘AM Envelope’ (Additive Manufacturing Envelope describes the transfer of this technology to the building envelope. Additive Fabrication is a building block that aids in developing the building envelope from a mere space enclosure to a dynamic building envelope. First beginnings of AM facade construction show up when dealing with relevant aspects like material consumption, mounting or part’s performance. From those starting points several parts of an existing post-and-beam façade system were optimized, aiming toward the implementation of AM into the production chain. Enhancements on all different levels of production were achieved: storing, producing, mounting and performance. AM offers the opportunity to manufacture facades ‘just in time’. It is no longer necessary to store or produce large numbers of parts in advance. Initial investment for tooling can be avoided, as design improvements can be realized within the dataset of the AM part. AM is based on ‘tool-less’ production, all parts can be further developed with every new generation. Producing tool-less also allows for new shapes and functional parts in small batch sizes – down to batch size one. The parts performance can be re-interpreted based on the demands within the system, not based on the limitations of conventional manufacturing. AM offers new ways of materializing the physical part around its function. It leads toward customized

  2. 78 FR 5148 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection: General...

    Science.gov (United States)

    2013-01-24

    ... failure states occur in the electronic flight control system, flight envelope protection features can... Envelope Protection: General Limiting Requirements AGENCY: Federal Aviation Administration (FAA), DOT...), specifically new control architecture and a full digital flight control system which provides flight envelope...

  3. Stability charts for uniform slopes in soils with nonlinear failure envelopes

    OpenAIRE

    Eid, Hisham T.

    2014-01-01

    Based on the results of an extensive parametric study, charts were developed for assessment of the stability of uniform slopes in soils with nonlinear shear strength failure envelopes. The study was conducted using envelopes formed to represent the realistic shapes of soil nonlinear drained strength envelopes and the associated different degrees of nonlinearity. The introduction of a simple methodology to describe the nonlinear envelopes and a stability parameter, the value of which depends o...

  4. Comprehensive search for intra- and inter-specific sequence polymorphisms among coding envelope genes of retroviral origin found in the human genome: genes and pseudogenes

    Directory of Open Access Journals (Sweden)

    Vasilescu Alexandre

    2005-09-01

    Full Text Available Abstract Background The human genome carries a high load of proviral-like sequences, called Human Endogenous Retroviruses (HERVs, which are the genomic traces of ancient infections by active retroviruses. These elements are in most cases defective, but open reading frames can still be found for the retroviral envelope gene, with sixteen such genes identified so far. Several of them are conserved during primate evolution, having possibly been co-opted by their host for a physiological role. Results To characterize further their status, we presently sequenced 12 of these genes from a panel of 91 Caucasian individuals. Genomic analyses reveal strong sequence conservation (only two non synonymous Single Nucleotide Polymorphisms [SNPs] for the two HERV-W and HERV-FRD envelope genes, i.e. for the two genes specifically expressed in the placenta and possibly involved in syncytiotrophoblast formation. We further show – using an ex vivo fusion assay for each allelic form – that none of these SNPs impairs the fusogenic function. The other envelope proteins disclose variable polymorphisms, with the occurrence of a stop codon and/or frameshift for most – but not all – of them. Moreover, the sequence conservation analysis of the orthologous genes that can be found in primates shows that three env genes have been maintained in a fully coding state throughout evolution including envW and envFRD. Conclusion Altogether, the present study strongly suggests that some but not all envelope encoding sequences are bona fide genes. It also provides new tools to elucidate the possible role of endogenous envelope proteins as susceptibility factors in a number of pathologies where HERVs have been suspected to be involved.

  5. The dynamical evolution of the Orion Trapezium

    Science.gov (United States)

    Allen, C.; Costero, R.; Ruelas-Mayorga, A.; Sánchez, L.

    2018-01-01

    Using recent observational data on transverse and radial velocities of the bright Orion Trapezium stars we study the dynamical evolution of ensembles of systems mimicking the Trapezium. To this end we perform numerical N-body integrations using the observed planar positions and velocities, the radial velocities, and random z-positions for all components. We include perturbations in these quantities compatible with the observational errors. We discuss the dynamical outcome of the evolution of such systems and the properties of the resulting binaries.

  6. Sound Velocity in Soap Foams

    International Nuclear Information System (INIS)

    Wu Gong-Tao; Lü Yong-Jun; Liu Peng-Fei; Li Yi-Ning; Shi Qing-Fan

    2012-01-01

    The velocity of sound in soap foams at high gas volume fractions is experimentally studied by using the time difference method. It is found that the sound velocities increase with increasing bubble diameter, and asymptotically approach to the value in air when the diameter is larger than 12.5 mm. We propose a simple theoretical model for the sound propagation in a disordered foam. In this model, the attenuation of a sound wave due to the scattering of the bubble wall is equivalently described as the effect of an additional length. This simplicity reasonably reproduces the sound velocity in foams and the predicted results are in good agreement with the experiments. Further measurements indicate that the increase of frequency markedly slows down the sound velocity, whereas the latter does not display a strong dependence on the solution concentration

  7. Settling velocities in batch sedimentation

    International Nuclear Information System (INIS)

    Fricke, A.M.; Thompson, B.E.

    1982-10-01

    The sedimentation of mixtures containing one and two sizes of spherical particles (44 and 62 μm in diameter) was studied. Radioactive tracing with 57 Co was used to measure the settling velocities. The ratio of the settling velocity U of uniformly sized particles to the velocity predicted to Stokes' law U 0 was correlated to an expression of the form U/U 0 = epsilon/sup α/, where epsilon is the liquid volume fraction and α is an empirical constant, determined experimentally to be 4.85. No effect of viscosity on the ratio U/U 0 was observed as the viscosity of the liquid medium was varied from 1x10 -3 to 5x10 -3 Pa.s. The settling velocities of particles in a bimodal mixture were fit by the same correlation; the ratio U/U 0 was independent of the concentrations of different-sized particles

  8. Evolution of the giant planets

    International Nuclear Information System (INIS)

    Bodenheimer, P.

    1985-01-01

    The theory of the evolution of the giant planets is discussed with emphasis on detailed numerical calculations in the spherical approximation. Initial conditions are taken to be those provided by the two main hypotheses for the origin of the giant planets. If the planets formed by gravitational instability in the solar nebula, the initial mass is comparable to the present mass or larger. The evolution then goes through the following phases: (1) an initial contraction phase in hydrostatic equilibrium; (2) a hydrodynamic collapse induced by molecular dissociation; and (3) a second equilibrium phase involving contraction and cooling to the present state. During phase (1) a rock-ice core must form by precipitation or accretion. If, on the other hand, the giant planets formed by first accreting a solid core and then capturing gas from the surrounding nebula, then the evolutionary phases are as follows: (1) a period during which planetesimals accrete to form a core of about one earth mass, composed of rock and ice; (2) a gas accretion phase, during which a relatively low-mass gaseous envelope in hydrostatic equilibrium exists around the core, which itself continues to grow to 10 to 20 Earth masses; (3) the point of arrival at the ''critical'' core mass at which point the accretion of gas is much faster than the accretion of the core, and the envelope contracts rapidly; (4) continuation of accretion of gas from the nebula and buildup of the envelope mass to its present value (for the case of Jupiter or Saturn); and (5) a final phase, after termination of accretion, during which the protoplanet contracts and cools to its present state. Some observational constraints are described, and some problems with the two principal hypotheses are discussed

  9. Dynamical model for the dusty envelope around the symbiotic nova PU Vulpeculae

    International Nuclear Information System (INIS)

    Men'shchikov, A.B.; Tutukov, A.V.; Shustov, B.M.; Ergma, E.V.

    1985-01-01

    An evolutionary model for PU Vul, Object Kuwano--Honda, indicates that the deep 1980--1981 minimum may have resulted from detachment of a dust envelope. The envelope ejection process and the changes in the infrared spectrum are studied numerically; evidently the envelope departs strongly from spherical symmetry. The bluing observed at minimum light might have been due to dissipation of shock energy

  10. Online Wavelet Complementary velocity Estimator.

    Science.gov (United States)

    Righettini, Paolo; Strada, Roberto; KhademOlama, Ehsan; Valilou, Shirin

    2018-02-01

    In this paper, we have proposed a new online Wavelet Complementary velocity Estimator (WCE) over position and acceleration data gathered from an electro hydraulic servo shaking table. This is a batch estimator type that is based on the wavelet filter banks which extract the high and low resolution of data. The proposed complementary estimator combines these two resolutions of velocities which acquired from numerical differentiation and integration of the position and acceleration sensors by considering a fixed moving horizon window as input to wavelet filter. Because of using wavelet filters, it can be implemented in a parallel procedure. By this method the numerical velocity is estimated without having high noise of differentiators, integration drifting bias and with less delay which is suitable for active vibration control in high precision Mechatronics systems by Direct Velocity Feedback (DVF) methods. This method allows us to make velocity sensors with less mechanically moving parts which makes it suitable for fast miniature structures. We have compared this method with Kalman and Butterworth filters over stability, delay and benchmarked them by their long time velocity integration for getting back the initial position data. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  11. Dynamical Evolution of Ring-Satellite Systems

    Science.gov (United States)

    Ohtsuki, Keiji

    2005-01-01

    The goal of this research was to understand dynamical processes related to the evolution of size distribution of particles in planetary rings and application of theoretical results to explain features in the present rings of giant planets. We studied velocity evolution and accretion rates of ring particles in the Roche zone. We developed a new numerical code for the evolution of ring particle size distribution, which takes into account the above results for particle velocity evolution and accretion rates. We also studied radial diffusion rate of ring particles due to inelastic collisions and gravitational encounters. Many of these results can be also applied to dynamical evolution of a planetesimal disk. Finally, we studied rotation rates of moonlets and particles in planetary rings, which would influence the accretional evolution of these bodies. We describe our key accomplishments during the past three years in more detail in the following.

  12. Superluminal velocities. Illusion or reality?

    International Nuclear Information System (INIS)

    Pereyra, P.; Simanjuntak, H.P.

    2005-10-01

    We study the time-evolution of electromagnetic wave packets through optical superlattices. We follow the time evolution (described by Maxwell equations) of Gaussian packets with centroid in different energy regions. The time spent by the wave packet inside an optical structure agrees extremely well with the superluminal experimental results and the phase time predictions. (author)

  13. Turbulent structure of thermal plume. Velocity field

    International Nuclear Information System (INIS)

    Guillou, B.; Brahimi, M.; Doan-kim-son

    1986-01-01

    An experimental investigation and a numerical study of the dynamics of a turbulent plume rising from a strongly heated source are described. This type of flow is met in thermal effluents (air, vapor) from, e.g., cooling towers of thermal power plants. The mean and fluctuating values of the vertical component of the velocity were determined using a Laser-Doppler anemometer. The measurements allow us to distinguish three regions in the plume-a developing region near the source, an intermediate region, and a self-preserving region. The characteristics of each zone have been determined. In the self-preserving zone, especially, the turbulence level on the axis and the entrainment coefficient are almost twice of the values observed in jets. The numerical model proposed takes into account an important phenomenon, the intermittency, observed in the plume. This model, established with the self-preserving hypothesis, brings out analytical laws. These laws and the predicted velocity profile are in agreement with the experimental evolutions [fr

  14. The Physics and Chemistry of Oxygen-Rich Circumstellar Envelopes as Traced by Simple Molecules

    Science.gov (United States)

    Wong, Ka Tat

    2018-04-01

    background stellar continuum has been clearly imaged in the (sub)millimetre wavelength regime. Through radiative transfer modelling of the SiO and H2O line absorption and emission, it is found that during the ALMA observations, the extended atmosphere of the star exhibited infall motions in general with a shock front of velocity evolution.

  15. Serial femtosecond X-ray diffraction of enveloped virus microcrystals

    Directory of Open Access Journals (Sweden)

    Robert M. Lawrence

    2015-07-01

    Full Text Available Serial femtosecond crystallography (SFX using X-ray free-electron lasers has produced high-resolution, room temperature, time-resolved protein structures. We report preliminary SFX of Sindbis virus, an enveloped icosahedral RNA virus with ∼700 Å diameter. Microcrystals delivered in viscous agarose medium diffracted to ∼40 Å resolution. Small-angle diffuse X-ray scattering overlaid Bragg peaks and analysis suggests this results from molecular transforms of individual particles. Viral proteins undergo structural changes during entry and infection, which could, in principle, be studied with SFX. This is an important step toward determining room temperature structures from virus microcrystals that may enable time-resolved studies of enveloped viruses.

  16. Virulence properties of the Legionella pneumophila cell envelope

    Directory of Open Access Journals (Sweden)

    Olga eShevchuk

    2011-04-01

    Full Text Available The bacterial envelope plays a crucial role in the pathogenesis of infectious diseases. In this review, we summarize the current knowledge of the structure and molecular composition of the Legionella pneumophila cell envelope. We describe LPS biosynthesis and the biological activities of membrane and periplasmic proteins and discuss their decisive functions during the pathogen-host interaction. In addition to adherence, invasion and intracellular survival of L. pneumophila, special emphasis is laid on iron acquisition, detoxification, key elicitors of the immune response and the diverse functions of outer membrane vesicles. The critical analysis of the literature reveals that the dynamics and phenotypic plasticity of the Legionella cell surface during the different metabolic stages requires more attention in the future.

  17. Maximum Torque and Momentum Envelopes for Reaction Wheel Arrays

    Science.gov (United States)

    Markley, F. Landis; Reynolds, Reid G.; Liu, Frank X.; Lebsock, Kenneth L.

    2009-01-01

    Spacecraft reaction wheel maneuvers are limited by the maximum torque and/or angular momentum that the wheels can provide. For an n-wheel configuration, the torque or momentum envelope can be obtained by projecting the n-dimensional hypercube, representing the domain boundary of individual wheel torques or momenta, into three dimensional space via the 3xn matrix of wheel axes. In this paper, the properties of the projected hypercube are discussed, and algorithms are proposed for determining this maximal torque or momentum envelope for general wheel configurations. Practical strategies for distributing a prescribed torque or momentum among the n wheels are presented, with special emphasis on configurations of four, five, and six wheels.

  18. Functional envelope of a non-autonomous discrete system

    Directory of Open Access Journals (Sweden)

    Barzanouni Ali

    2017-11-01

    Full Text Available Let (X, F = {fn}n =0∞ be a non-autonomous discrete system by a compact metric space X and continuous maps fn : X → X, n = 0, 1, ....We introduce functional envelope (S(X, G = {Gn}n =0∞, of (X, F = {fn}n =0∞, where S(X is the space of all continuous self maps of X and the map Gn : S(X → S(X is defined by Gn(ϕ = Fn ∘ ϕ, Fn = fn ∘ fn-1 ∘ . . . ∘ f1 ∘ f0. The paper mainly deals with the connection between the properties of a system and the properties of its functional envelope.

  19. Efficiency in the Worst Production Situation Using Data Envelopment Analysis

    Directory of Open Access Journals (Sweden)

    Md. Kamrul Hossain

    2013-01-01

    Full Text Available Data envelopment analysis (DEA measures relative efficiency among the decision making units (DMU without considering noise in data. The least efficient DMU indicates that it is in the worst situation. In this paper, we measure efficiency of individual DMU whenever it losses the maximum output, and the efficiency of other DMUs is measured in the observed situation. This efficiency is the minimum efficiency of a DMU. The concept of stochastic data envelopment analysis (SDEA is a DEA method which considers the noise in data which is proposed in this study. Using bounded Pareto distribution, we estimate the DEA efficiency from efficiency interval. Small value of shape parameter can estimate the efficiency more accurately using the Pareto distribution. Rank correlations were estimated between observed efficiencies and minimum efficiency as well as between observed and estimated efficiency. The correlations are indicating the effectiveness of this SDEA model.

  20. A deformation (strain) envelope for cyclic disturbed sand

    DEFF Research Database (Denmark)

    Sabaliauskas, Tomas; Ibsen, Lars Bo

    2018-01-01

    Recent advances in triaxial testing procedures revealed new properties governing disturbed sand stiffness. This paper summarizes the new observations into an original, proof of concept. The novel concept interpolates effective stress within a strain (deformation) envelope. Coulomb stress limits...... are still satisfied, but the stresses are interpolated using a deformation (strain) envelope. The method is not part of a constitutive formulation, but is remarkably functional in triaxial testing practice. The practicality is proven by plotting simulations on top of empirically measured stiffness history...... - the fitting is remarkably good even during tests of extreme complexity. The novelty has substantial interdisciplinary potential: offshore anchors and foundations, earthquakes and industrial processes - wherever dynamic loads and disturbed sand are encountered. It opens the door to a new branch of numerical...

  1. Enveloped Lives: Practicing Health and Care in Lithuania.

    Science.gov (United States)

    Praspaliauskiene, Rima

    2016-12-01

    This article analyzes informal medical payments that the majority of Lithuanians give or feel compelled to give to doctors before or after treatment. It focuses on how patients and their caretakers encounter, practice, and enact informal payments in health care and how these payments create a reality of health care that is not limited to an economic rationality. Within such a frame, rather than being considered a gift or bribe, it conceptualizes these little white envelopes as a practice of health and care. The article shows how an envelope of money given to a doctor transcends the material patient-doctor transaction and emerges as a productive force for coping with illness, medical encounters, and misfortunes. © 2016 by the American Anthropological Association.

  2. Interior thermal insulation systems for historical building envelopes

    Science.gov (United States)

    Jerman, Miloš; Solař, Miloš; Černý, Robert

    2017-11-01

    The design specifics of interior thermal insulation systems applied for historical building envelopes are described. The vapor-tight systems and systems based on capillary thermal insulation materials are taken into account as two basic options differing in building-physical considerations. The possibilities of hygrothermal analysis of renovated historical envelopes including laboratory methods, computer simulation techniques, and in-situ tests are discussed. It is concluded that the application of computational models for hygrothermal assessment of interior thermal insulation systems should always be performed with a particular care. On one hand, they present a very effective tool for both service life assessment and possible planning of subsequent reconstructions. On the other, the hygrothermal analysis of any historical building can involve quite a few potential uncertainties which may affect negatively the accuracy of obtained results.

  3. On the Origin of Sub-subgiant Stars. II. Binary Mass Transfer, Envelope Stripping, and Magnetic Activity

    Energy Technology Data Exchange (ETDEWEB)

    Leiner, Emily; Mathieu, Robert D. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Geller, Aaron M., E-mail: leiner@astro.wisc.edu [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States)

    2017-05-10

    Sub-subgiant stars (SSGs) lie to the red of the main sequence and fainter than the red giant branch in cluster color–magnitude diagrams (CMDs), a region not easily populated by standard stellar evolution pathways. While there has been speculation on what mechanisms may create these unusual stars, no well-developed theory exists to explain their origins. Here we discuss three hypotheses of SSG formation: (1) mass transfer in a binary system, (2) stripping of a subgiant’s envelope, perhaps during a dynamical encounter, and (3) reduced luminosity due to magnetic fields that lower convective efficiency and produce large starspots. Using the stellar evolution code MESA, we develop evolutionary tracks for each of these hypotheses, and compare the expected stellar and orbital properties of these models with six known SSGs in the two open clusters M67 and NGC 6791. All three of these mechanisms can create stars or binary systems in the SSG CMD domain. We also calculate the frequency with which each of these mechanisms may create SSG systems, and find that the magnetic field hypothesis is expected to create SSGs with the highest frequency in open clusters. Mass transfer and envelope stripping have lower expected formation frequencies, but may nevertheless create occasional SSGs in open clusters. They may also be important mechanisms to create SSGs in higher mass globular clusters.

  4. Thermonuclear process and accretion onto neutron star envelopes: x-ray burst and transient sources

    International Nuclear Information System (INIS)

    Starrfield, S.; Kenyon, S.; Sparks, W.M.; Truran, J.W.; Theoretical Division, Los Alamos National Laboratory)

    1982-01-01

    We have used a Lagrangian, fully implicit, one-dimensional, hydrodynamic computer code to investigate the evolution of thermonuclear runaways in the thick, accreted, hydrogen-rich envelopes of 1.0 M/sub sun/ neutron stars with radii of 10 km and 20 km. Our simulations produce outbursts which range in time scale from about 2000 seconds to longer than 1 day. Peak effective temperature was 3.3 x 10 7 K (kTapprox.2.91 keV), and peak luminosity was 2 x 10 5 L/sub sun/ for the 10 km study. The 20 km neutron star produced a peak effective temperature and luminosity of 5.3 x 10 6 K and 5.9 x 10 2 L/sub sun/, respectively. We also investigated the effects of changes in the rates of the 14 O(α,p) and 15 O(α,ν) reactions on the evolution. Hydrodynamic expansion on the 10 km neutron star produced a precursor lasting about 10 - 6 seconds

  5. The psychic envelopes in psychoanalytic theories of infancy

    Science.gov (United States)

    Mellier, Denis

    2014-01-01

    This paper aims to review the topic of psychic envelopes and to sketch the main outlines of this concept in infancy. We first explore the origins of the concept in Freud's “protective shield” and then its development in adult psychoanalysis before going on to see how this fits in infancy with post-Bionian psychoanalysis and development. Four central notions guide this review: (1) Freud's “protective shield” describes a barrier to protect the psychic apparatus against potentially overflowing trauma. It is a core notion which highlights a serious clinical challenge for patients for whom the shield is damaged or faulty: the risk of confusion of borders between the internal/external world, conscious/unconscious, mind/body, or self-conservation/sexuality. (2) Anzieu's “Skin-Ego” is defined by the different senses of the body. The different layers of experienced sensation, of this body-ego, go on to form the psychic envelope. This theory contributes to our understanding of how early trauma, due to the failures of maternal care, can continue to have an impact in adult life. (3) Bick's “psychic skin” establishes the concept in relation to infancy. The mother's containing functions allow a first psychic skin to develop, which then defines an infant's psychic space and affords the infant a degree of self-containment. Houzel then conceptualized this process as a stabilization of drive forces. (4) Stern's “narrative envelope” derives from the intersection between psychoanalysis and neuroscience. It gives us another way to conceptualize the development of pre-verbal communication. It may also pave the way for a finer distinction of different types of envelopes. Ultimately, in this review we find that psychic envelopes in infancy can be viewed from four different perspectives (economic, topographical, dynamic, and genetic) and recommend further investigation. PMID:25076924

  6. Maximum Likelihood, Consistency and Data Envelopment Analysis: A Statistical Foundation

    OpenAIRE

    Rajiv D. Banker

    1993-01-01

    This paper provides a formal statistical basis for the efficiency evaluation techniques of data envelopment analysis (DEA). DEA estimators of the best practice monotone increasing and concave production function are shown to be also maximum likelihood estimators if the deviation of actual output from the efficient output is regarded as a stochastic variable with a monotone decreasing probability density function. While the best practice frontier estimator is biased below the theoretical front...

  7. The Use of Categorical Variables in Data Envelopment Analysis

    OpenAIRE

    Rajiv D. Banker; Richard C. Morey

    1986-01-01

    Data Envelopment Analysis has now been extensively applied in a range of empirical settings to identify relative inefficiencies, and provide targets for improvements. It accomplishes this by developing peer groups for each unit being operated. The use of categorical variables is an important extension which can improve the peer group construction process and incorporate "on-off" characteristics, e.g., presence of drive-in window or not in a banking network. It relaxes the stringent need for f...

  8. Windows and Envelope R&D Opportunities Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Building Technologies Office

    2018-02-01

    BTO's Emerging Technologies program held a two-day workshop on “Windows and Envelope R&D Opportunities” on May 31 and June 1, 2017 at the Illinois Institute of Technology in Chicago, Illinois. A broad range of about 100 experts from industry, academia, national laboratories, and government participated, contributing their ideas, insights, and perspectives. Their feedback is intended to help inform and augment BTO’s research and development activities.

  9. Biomimetic Architecture in Building Envelope Maintenance (A Literature

    Directory of Open Access Journals (Sweden)

    Agus Salim N.A.

    2014-01-01

    Full Text Available The study of biomimetic architecture on building envelope is the main structure of this research. The concept is believed more sustainable and efficient for energy saving, operating cost consumption, waste recycle and design renewal in the future. The inspiration from the nature developed the intention on this study to explore on what and how this concept to overcome the problems through design. Biomimicry does catch the attention of human to study more on the system and function of its nature course. The designers are not exception influenced by this concept when the form, shape, texture and colour inspired them in their design. The domination of building form will affect the building envelope as the skin of the structure. A clear impact on building failure is begun with building envelope appearance without a proper maintenance. The faults in building design place a heavy burden on the building for the rest of its operational life and there is no compensation for it. In such situations, the responsibility falls on the shoulders of the designer.

  10. Specifics of Building Envelope Air Leakage Problems and Airtightness Measurements

    Directory of Open Access Journals (Sweden)

    Borodinecs Anatolijs

    2016-01-01

    Full Text Available In addition to transmission heat loses the infiltration of outdoor air can cause significant heat losses. The external building envelope should be airtight in order to prevent uncontrolled cold air infiltration. The article analysis modern building materials and structures influence on airtightness. The practical measurements of renovated buildings’ airtightness are presented and compared to non-renovated buildings. In addition paper presents data on airtightness measurements of whole multi apartment building and single apartment in analyzed building taking inco accout properties of building materials. The airtightness of single apartment was evaluated with support pressure in neighbor apartments. The results show that the airtightness measurements of multi apartment building can be evaluated by measuring single apartment on last floor with support pressure in neighbor apartments. The practical measurement of renovated buildings had shown the air leakage rate q50 of typical Latvian construction after renovation is between 2.5 and 2.9 m3/(m2·h. Since the building envelope has to minimize the heat loses (transmission and infiltration and ventilation system either mechanical or natural has to provide necessary air exchange, the building envelope airtightness shouldn’t be dependent on type of ventilation systems.

  11. Experiences when employing different alternatives for envelope upgrading

    Directory of Open Access Journals (Sweden)

    Peru Elguezabal Esnarrizaga

    2015-06-01

    Full Text Available The challenges of achieving the 2020 goals in terms of energy savings and improving efficiency are guiding numerous research initiatives looking for more insulated envelopes, dealing with thermal performance of insulation materials and envelope systems. Nevertheless, the envelope integrates within the building and this improvement on the insulation performance has to be properly adopted, taking into account the interrelation of main elements composing the overall system (facade, frame, slabs, openings, partitions etc., as well as side effects originated not only for new erected buildings, but specifically in renovation and retrofitting works. This paper describes real experiences when considering various options for upgrading the facade through the increase of the insulation capacity, starting from external overcladding prefabricated panels and ventilated facades, advancing to more sustainable low carbon systems and ending with even more highly insulated solutions employing aerogels. Lessons from these cases, where energy and hygrothermal assessments have being carried out, demonstrate the influence of the design and construction phases and the relevance of disregarded effects such as minor thermal bridges, uncontrolled craftsmanship on site, and moisture transfer for the different technologies considered. Finally, possible alternatives are provided to overcome some of the detected difficulties, such as combination with non-metallic structural components and building membranes, and being prepared for future challenges and new developments when these isolative elements are combined with other technologies, as for example, renewable energy harvesting devices.  

  12. Thermal performance envelopes for MHTGRs - Reliability by design

    International Nuclear Information System (INIS)

    Etzel, K.T.; Howard, W.W.; Zgliczynski, J.

    1992-01-01

    Thermal performance envelopes are used to specify steady-state design requirements for the systems of the modular high-temperature gas-cooled reactor (MHTGR) to maximize plant performance reliability with optimized design. The thermal performance envelopes are constructed around the expected operating point to account for uncertainties in actual plant as-built parameters and plant operation. The components are then designed to perform successfully at all points within the envelope. As a result, plant reliability is maximized by accounting for component thermal performance variation in the design. The design is optimized by providing a means to determine required margins in a disciplined and visible fashion. This is accomplished by coordinating these requirements with the various system and component designers in the early stages of the design, applying the principles of total quality management. The design is challenged by the more complex requirements associated with a range of operating conditions, but in return, high probability of delivering reliable performance throughout the plant life is ensured

  13. The epigenetics of nuclear envelope organization and disease

    International Nuclear Information System (INIS)

    Schirmer, Eric C.

    2008-01-01

    Mammalian chromosomes and some specific genes have non-random positions within the nucleus that are tissue-specific and heritable. Work in many organisms has shown that genes at the nuclear periphery tend to be inactive and altering their partitioning to the interior results in their activation. Proteins of the nuclear envelope can recruit chromatin with specific epigenetic marks and can also recruit silencing factors that add new epigenetic modifications to chromatin sequestered at the periphery. Together these findings indicate that the nuclear envelope is a significant epigenetic regulator. The importance of this function is emphasized by observations of aberrant distribution of peripheral heterochromatin in several human diseases linked to mutations in NE proteins. These debilitating inherited diseases range from muscular dystrophies to the premature aging progeroid syndromes and the heterochromatin changes are just one early clue for understanding the molecular details of how they work. The architecture of the nuclear envelope provides a unique environment for epigenetic regulation and as such a great deal of research will be required before we can ascertain the full range of its contributions to epigenetics

  14. Infection of human and non-human cells by a highly fusogenic primary CD4-independent HIV-1 isolate with a truncated envelope cytoplasmic tail

    International Nuclear Information System (INIS)

    Saha, Kunal; Yan Hui; Nelson, Julie A.E.; Zerhouni-Layachi, Bouchra

    2005-01-01

    Truncation of the envelope cytoplasmic tail has enabled FIV, SIV, and some laboratory HIV-1 strains to acquire broader cellular tropism and enhanced fusogenicity. Here we have characterized a primary CD4-independent HIV-1 isolate (92UG046-T8) with a truncated cytoplasmic tail that was able to infect and induce syncytia in primary lymphocytes from human, chimpanzee, and monkey, as well as CD4-negative cell lines from human and monkey. Increased syncytia were also noticeable with 293 cells expressing the cloned envelope from the 92UG046-T8 isolate suggesting envelope-mediated cellular fusion. Except pooled serum from HIV-1-infected individuals, monoclonal anti-envelope antibodies or antibodies/antagonists against CD4, CXCR4, and CCR5 were not able to prevent infection by the 92UG046-T8 isolate. This is the first report showing a primary HIV-1 variant with truncated cytoplasmic tail which is highly fusogenic and can infect a broad range of cells from human and non-human origins. In vivo evolution of similar HIV-1 mutants may have important implications in AIDS pathogenesis

  15. CARBON CHEMISTRY IN THE ENVELOPE OF VY CANIS MAJORIS: IMPLICATIONS FOR OXYGEN-RICH EVOLVED STARS

    International Nuclear Information System (INIS)

    Ziurys, L. M.; Tenenbaum, E. D.; Pulliam, R. L.; Woolf, N. J.; Milam, S. N.

    2009-01-01

    Observations of the carbon-bearing molecules CO, HCN, CS, HNC, CN, and HCO + have been conducted toward the circumstellar envelope of the oxygen-rich red supergiant star, VY Canis Majoris (VY CMa), using the Arizona Radio Observatory (ARO). CO and HCN were also observed toward the O-rich shells of NML Cyg, TX Cam, IK Tau, and W Hya. Rotational transitions of these species at 1 mm, 0.8 mm, and 0.4 mm were measured with the ARO Submillimeter Telescope, including the J = 6 → 5 line of CO at 691 GHz toward TX Cam and W Hya. The ARO 12 m was used for 2 mm and 3 mm observations. Four transitions were observed for HCO + in VY CMa, the first definitive identification of this ion in a circumstellar envelope. Molecular line profiles from VY CMa are complex, indicating three separate outflows: a roughly spherical flow and separate red- and blueshifted winds, as suggested by earlier observations. Spectra from the other sources appear to trace a single outflow component. The line data were modeled with a radiative transfer code to establish molecular abundances relative to H 2 and source distributions. Abundances for CO derived for these objects vary over an order of magnitude, f ∼ 0.4-5 x 10 -4 , with the lower values corresponding to the supergiants. For HCN, a similar range in abundance is found (f ∼ 0.9-9 x 10 -6 ), with no obvious dependence on the mass-loss rate. In VY CMa, HCO + is present in all three outflows with f ∼ 0.4-1.6 x 10 -8 and a spatial extent similar to that of CO. HNC is found only in the red- and blueshifted components with [HCN]/[HNC] ∼ 150-190, while [CN]/[HCN] ∼ 0.01 in the spherical flow. All three velocity components are traced in CS, which has a confined spatial distribution and f ∼ 2-6 x 10 -7 . These observations suggest that carbon-bearing molecules in O-rich shells are produced by a combination of photospheric shocks and photochemistry. Shocks may play a more prominent role in the supergiants because of their macroturbulent

  16. Carbon Chemistry in the Envelope of VY Canis Majoris: Implications for Oxygen-Rich Evolved Stars

    Science.gov (United States)

    Ziurys, L. M.; Tenenbaum, E. D.; Pulliam, R. L.; Woolf, N. J.; Milam, S. N.

    2009-04-01

    Observations of the carbon-bearing molecules CO, HCN, CS, HNC, CN, and HCO+ have been conducted toward the circumstellar envelope of the oxygen-rich red supergiant star, VY Canis Majoris (VY CMa), using the Arizona Radio Observatory (ARO). CO and HCN were also observed toward the O-rich shells of NML Cyg, TX Cam, IK Tau, and W Hya. Rotational transitions of these species at 1 mm, 0.8 mm, and 0.4 mm were measured with the ARO Submillimeter Telescope, including the J = 6 → 5 line of CO at 691 GHz toward TX Cam and W Hya. The ARO 12 m was used for 2 mm and 3 mm observations. Four transitions were observed for HCO+ in VY CMa, the first definitive identification of this ion in a circumstellar envelope. Molecular line profiles from VY CMa are complex, indicating three separate outflows: a roughly spherical flow and separate red- and blueshifted winds, as suggested by earlier observations. Spectra from the other sources appear to trace a single outflow component. The line data were modeled with a radiative transfer code to establish molecular abundances relative to H2 and source distributions. Abundances for CO derived for these objects vary over an order of magnitude, f ~ 0.4-5 × 10-4, with the lower values corresponding to the supergiants. For HCN, a similar range in abundance is found (f ~ 0.9-9 × 10-6), with no obvious dependence on the mass-loss rate. In VY CMa, HCO+ is present in all three outflows with f ~ 0.4-1.6 × 10-8 and a spatial extent similar to that of CO. HNC is found only in the red- and blueshifted components with [HCN]/[HNC] ~ 150-190, while [CN]/[HCN] ~ 0.01 in the spherical flow. All three velocity components are traced in CS, which has a confined spatial distribution and f ~ 2-6 × 10-7. These observations suggest that carbon-bearing molecules in O-rich shells are produced by a combination of photospheric shocks and photochemistry. Shocks may play a more prominent role in the supergiants because of their macroturbulent velocities.

  17. DOUBLE COMPACT OBJECTS. I. THE SIGNIFICANCE OF THE COMMON ENVELOPE ON MERGER RATES

    International Nuclear Information System (INIS)

    Dominik, Michal; Belczynski, Krzysztof; Bulik, Tomasz; Fryer, Christopher; Holz, Daniel E.; Berti, Emanuele; Mandel, Ilya; O'Shaughnessy, Richard

    2012-01-01

    The last decade of observational and theoretical developments in stellar and binary evolution provides an opportunity to incorporate major improvements to the predictions from population synthesis models. We compute the Galactic merger rates for NS-NS, BH-NS, and BH-BH mergers with the StarTrack code. The most important revisions include updated wind mass-loss rates (allowing for stellar-mass black holes up to 80 M ☉ ), a realistic treatment of the common envelope phase (a process that can affect merger rates by 2-3 orders of magnitude), and a qualitatively new neutron star/black hole mass distribution (consistent with the observed m ass gap ) . Our findings include the following. (1) The binding energy of the envelope plays a pivotal role in determining whether a binary merges within a Hubble time. (2) Our description of natal kicks from supernovae plays an important role, especially for the formation of BH-BH systems. (3) The masses of BH-BH systems can be substantially increased in the case of low metallicities or weak winds. (4) Certain combinations of parameters underpredict the Galactic NS-NS merger rate and can be ruled out. (5) Models incorporating delayed supernovae do not agree with the observed NS/BH 'mass gap', in accordance with our previous work. This is the first in a series of three papers. The second paper will study the merger rates of double compact objects as a function of redshift, star formation rate, and metallicity. In the third paper, we will present the detection rates for gravitational-wave observatories, using up-to-date signal waveforms and sensitivity curves.

  18. Optical spectra of 73 stripped-envelope core-collapse supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Modjaz, M.; Bianco, F. B.; Liu, Y. Q. [Center for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Blondin, S. [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388, Marseille (France); Kirshner, R. P.; Challis, P.; Hicken, M.; Marion, G. H. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Matheson, T. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Berlind, P.; Calkins, M. L. [F. L. Whipple Observatory, 670 Mt. Hopkins Road, P.O. Box 97, Amado, AZ 85645 (United States); Garnavich, P. [Department of Physics, 225 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556 (United States); Jha, S., E-mail: mmodjaz@nyu.edu [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States)

    2014-05-01

    We present 645 optical spectra of 73 supernovae (SNe) of Types IIb, Ib, Ic, and broad-lined Ic. All of these types are attributed to the core collapse of massive stars, with varying degrees of intact H and He envelopes before explosion. The SNe in our sample have a mean redshift (cz) = 4200 km s{sup –1}. Most of these spectra were gathered at the Harvard-Smithsonian Center for Astrophysics (CfA) between 2004 and 2009. For 53 SNe, these are the first published spectra. The data coverage ranges from mere identification (1-3 spectra) for a few SNe to extensive series of observations (10-30 spectra) that trace the spectral evolution for others, with an average of 9 spectra per SN. For 44 SNe of the 73 SNe presented here, we have well-determined dates of maximum light to determine the phase of each spectrum. Our sample constitutes the most extensive spectral library of stripped-envelope SNe to date. We provide very early coverage (as early as 30 days before V-band max) for photospheric spectra, as well as late-time nebular coverage when the innermost regions of the SN are visible (as late as 2 yr after explosion, while for SN 1993J, we have data as late as 11.6 yr). This data set has homogeneous observations and reductions that allow us to study the spectroscopic diversity of these classes of stripped SNe and to compare these to SNe-gamma-ray bursts. We undertake these matters in follow-up papers.

  19. Study of an experimental methodology for thermal properties diagnostic of building envelop

    Science.gov (United States)

    Yang, Yingying; Sempy, Alain; Vogt Wu, Tingting; Sommier, Alain; Dumoulin, Jean; Batsale, Jean Christophe

    2017-04-01

    The building envelope plays a critical role in determining levels of comfort and building efficiency. Its real thermal properties characterization is of major interest to be able to diagnose energy efficiency performance of buildings (new construction and retrofitted existing old building). Research and development on a possible methodology for energy diagnostic of the building envelop is a hot topic and necessary trend. Many kinds of sensors and instruments are used for the studies. The application of infrared (IR) thermography in non-destructive evaluation has been widely employed for qualitative evaluations for building diagnostics; meanwhile, the IR thermography technology also has a large potentiality for the evaluation of the thermal characteristics of the building envelope. Some promising recent research studies have been carried out with such contactless measurement technique. Nevertheless, research efforts are still required for in situ measurements under natural environmental conditions. In order to develop new solutions for non-intrusive evaluation of local thermal performance, enabling quantitative assessment of thermal properties of buildings and materials, experiments were carried out on a multi-layer pratical scale wall fixed on a caisson placed in a climatic chamber. Six halogen lamps (1.5 kW for each lamp) placed in front of objective wall were used to emulate sunny conditions. The radiative heat flux emitted was monitored and modulated with time according to typical weather data set encountered in France. Both steady state and transient regime heat transfer were studied during these experiments. Contact sensors (thermocouples, heat flux meters, Peltier sensors) and non-contact sensors (thermal IR camera, pyranometer) were used to measure the temperatures and heat flux density evolution. It has to be noticed that the Peltier sensors have been tuned and used with a specific processing to set them compliant for heat flux density measurements. The

  20. High pressure treatment under subfreezing temperature results in drastic inactivation of enveloped and non-enveloped viruses.

    Science.gov (United States)

    Kishida, T; Cui, F-D; Ohgitani, E; Gao, F; Hayakawa, K; Mazda, O

    2013-08-01

    Some viruses are sensitive to high pressure. The freeze-pressure generation method (FPGM) applies pressure as high as 250 MPa on a substance, simply by freezing a pressure-resistant reservoir in which the substance is immersed in water. Here we examined whether the FPGM successfully inactivates herpes simplex virus type 1 (HSV-1), an enveloped DNA virus belonging to the human Herpesviridae, and encephalomyocarditis virus (EMCV), an envelope-free RNA virus belonging to the Picornaviridae. After the treatment, HSV-1 drastically reduced the ability to form plaque in Vero cells in vitro as well as to kill mice in vivo. EMCV that had been pressurized failed to proliferate in HeLa cells and induce interferon response. The results suggest that the FPGM provides a feasible procedure to inactivate a broad spectrum of viruses.

  1. Effects of rotation on the evolution of primordial stars

    Science.gov (United States)

    Ekström, S.; Meynet, G.; Chiappini, C.; Hirschi, R.; Maeder, A.

    2008-10-01

    Context: Although still beyond our observational abilities, Population III stars are interesting objects from many perspectives. They are responsible for the re-ionisation of the inter-galactic medium. They also left their chemical imprint in the early Universe, which can be deciphered in the most metal-poor stars in the halo of our Galaxy. Aims: Rotation has been shown to play a determinant role at very low metallicity, bringing heavy mass loss where almost none was expected. Is this still true when the metallicity strictly equals zero? The aim of our study is to answer this question, and to determine how rotation changes the evolution and the chemical signature of the primordial stars. Methods: We have calculated seven differentially-rotating stellar models at zero metallicity, with masses between 9 and 200 M⊙. For each mass, we also calculated a corresponding model without rotation. The evolution is followed up to the pre-supernova stage. Results: We find that Z=0 models rotate with an internal profile Ω(r) close to local angular momentum conservation, because of a very weak core-envelope coupling. Rotational mixing drives an H-shell boost due to a sudden onset of the CNO cycle in the shell. This boost leads to a high 14N production, which can be as much as 106 times higher than the production of the non-rotating models. Generally, the rotating models produce much more metal than their non-rotating counterparts. The mass loss is very low, even for the models that reach critical velocity during the main sequence. It may however have an impact on the chemical enrichment of the Universe, because some of the stars are supposed to collapse directly into black holes. They would contribute to the enrichment only through their winds. While in that case non-rotating stars would not contribute at all, rotating stars may leave an imprint on their surrounding. Due to the low mass loss and the weak coupling, the core retains a high angular momentum at the end of the

  2. Velocity distribution in snow avalanches

    Science.gov (United States)

    Nishimura, K.; Ito, Y.

    1997-12-01

    In order to investigate the detailed structure of snow avalanches, we have made snow flow experiments at the Miyanomori ski jump in Sapporo and systematic observations in the Shiai-dani, Kurobe Canyon. In the winter of 1995-1996, a new device to measure static pressures was used to estimate velocities in the snow cloud that develops above the flowing layer of avalanches. Measurements during a large avalanche in the Shiai-dani which damaged and destroyed some instruments indicate velocities increased rapidly to more than 50 m/s soon after the front. Velocities decreased gradually in the following 10 s. Velocities of the lower flowing layer were also calculated by differencing measurement of impact pressure. Both recordings in the snow cloud and in the flowing layer changed with a similar trend and suggest a close interaction between the two layers. In addition, the velocity showed a periodic change. Power spectrum analysis of the impact pressure and the static pressure depression showed a strong peak at a frequency between 4 and 6 Hz, which might imply the existence of either ordered structure or a series of surges in the flow.

  3. Rapid Process to Generate Beam Envelopes for Optical System Analysis

    Science.gov (United States)

    Howard, Joseph; Seals, Lenward

    2012-01-01

    The task of evaluating obstructions in the optical throughput of an optical system requires the use of two disciplines, and hence, two models: optical models for the details of optical propagation, and mechanical models for determining the actual structure that exists in the optical system. Previous analysis methods for creating beam envelopes (or cones of light) for use in this obstruction analysis were found to be cumbersome to calculate and take significant time and resources to complete. A new process was developed that takes less time to complete beam envelope analysis, is more accurate and less dependent upon manual node tracking to create the beam envelopes, and eases the burden on the mechanical CAD (computer-aided design) designers to form the beam solids. This algorithm allows rapid generation of beam envelopes for optical system obstruction analysis. Ray trace information is taken from optical design software and used to generate CAD objects that represent the boundary of the beam envelopes for detailed analysis in mechanical CAD software. Matlab is used to call ray trace data from the optical model for all fields and entrance pupil points of interest. These are chosen to be the edge of each space, so that these rays produce the bounding volume for the beam. The x and y global coordinate data is collected on the surface planes of interest, typically an image of the field and entrance pupil internal of the optical system. This x and y coordinate data is then evaluated using a convex hull algorithm, which removes any internal points, which are unnecessary to produce the bounding volume of interest. At this point, tolerances can be applied to expand the size of either the field or aperture, depending on the allocations. Once this minimum set of coordinates on the pupil and field is obtained, a new set of rays is generated between the field plane and aperture plane (or vice-versa). These rays are then evaluated at planes between the aperture and field, at a

  4. Role of HIV-2 envelope in Lv2-mediated restriction

    International Nuclear Information System (INIS)

    Reuter, Sandra; Kaumanns, Patrick; Buschhorn, Sabine B.; Dittmar, Matthias T.

    2005-01-01

    We have characterized envelope protein pseudotyped HIV-2 particles derived from two HIV-2 isolates termed prCBL23 and CBL23 in order to define the role of the envelope protein for the Lv2-mediated restriction to infection. Previously, it has been described that the primary isolate prCBL23 is restricted to infection of several human cell types, whereas the T cell line adapted isolate CBL23 is not restricted in these cell types. Molecular cloning of the two isolates revealed that the env and the gag gene are responsible for the observed phenotype and that this restriction is mediated by Lv2, which is distinct from Ref1/Lv1 (Schmitz, C., Marchant, D., Neil, S.J., Aubin, K., Reuter, S., Dittmar, M.T., McKnight, A., Kizhatil, K., Albritton, L.M., 2004. Lv2, a novel postentry restriction, is mediated by both capsid and envelope. J. Virol. 78 (4), 2006-2016). We generated pseudotyped viruses consisting of HIV-2 (ROD-AΔenv-GFP, ROD-AΔenv-RFP, or ROD-AΔenv-REN) and the prCBL23 or CBL23 envelope proteins as well as chimeric proteins between these envelopes. We demonstrate that a single amino acid exchange at position 74 in the surface unit of CBL23-Env confers restriction to infection. This single point mutation causes tighter CD4 binding, resulting in a less efficient fusion into the cytosol of the restricted cell line. Prevention of endosome formation and prevention of endosome acidification enhance infectivity of the restricted particles for GHOST/X4 cells indicating a degradative lysosomal pathway as a cause for the reduced cytosolic entry. The described restriction to infection of the primary isolate prCBL23 is therefore largely caused by an entry defect. A remaining restriction to infection (19-fold) is preserved when endosomal acidification is prevented. This restriction to infection is also dependent on the presence of the point mutation at position 74 (G74E)

  5. Variation of Quench Propagation Velocities in YBCO Cables

    CERN Document Server

    Härö, E.; Stenvall, A.; 10.1007/s10948-015-2976-y

    2015-01-01

    changes during the quench. Due to the large temperature margin between the operation and the current sharing temperatures, the normal zone does not propagate with the temperature front. This means that the temperature will rise in a considerably larger volume when compared to the quenched volume. Thus, the evolution of the temperature distribution below current sharing temperature Tcs after the quench onset affects the normal zone propagation velocity in HTS more than in LTS coils. This can be seen as an acceleration of the quench propagation velocities while the quench evolves when margin to Tcs is high. In this paper we scrutinize quench propagation in a stack of YBCO cables with an in-house finite element method software which solves the heat diffusion equation. We compute the longitudinal and transverse normal zone propagation velocities at various distances from the hot spot to demonstrate the distance-variation...

  6. The Rapid Evolution of the Exciting Star of the Stingray Nebula

    Science.gov (United States)

    Reindl, N.; Rauch, T.; Parthasarathy, M.; Werner, K.; Kruk, J.W.; Hamann, W. R.; Sander, A.; Todt, H.

    2014-01-01

    Context: SAO244567, the exciting star of the Stingray nebula, is rapidly evolving. Previous analyses suggested that it has heated up from an effective temperature of about 21 kK in 1971 to over 50 kK in the 1990s. Canonical post-asymptotic giant branch evolution suggests a relatively high mass while previous analyses indicate a low-mass star. Aims: A comprehensive model-atmosphere analysis of UV and optical spectra taken during 1988-2006 should reveal the detailed temporal evolution of its atmospheric parameters and provide explanations for the unusually fast evolution. Methods: Fitting line profiles from static and expanding non-LTE model atmospheres to the observed spectra allowed us to study the temporal change of effective temperature, surface gravity, mass-loss rate, and terminal wind velocity. In addition, we determined the chemical composition of the atmosphere. Results: We find that the central star has steadily increased its effective temperature from 38 kK in 1988 to a peak value of 60 kK in 2002. During the same time, the star was contracting, as concluded from an increase in surface gravity from log g = 4.8 to 6.0 and a drop in luminosity. Simultaneously, the mass-loss rate declined from log(M/M (solar mass) yr (exp -1)) = -9.0 to -11.6 and the terminal wind velocity increased from v (infinity) = 1800 km s (exp -1) to 2800 km s (exp -1). Since around 2002, the star stopped heating and has cooled down again to 55 kK by 2006. It has a largely solar surface composition with the exception of slightly subsolar carbon, phosphorus, and sulfur. The results are discussed by considering different evolutionary scenarios. Conclusions: The position of SAO244567 in the log T (sub eff) -log g plane places the star in the region of sdO stars. By comparison with stellar-evolution calculations, we confirm that SAO244567 must be a low-mass star (M nebula with a kinematical age of only about 1000 years. We speculate that the star could be a late He-shell flash object

  7. Velocity Estimate Following Air Data System Failure

    National Research Council Canada - National Science Library

    McLaren, Scott A

    2008-01-01

    .... A velocity estimator (VEST) algorithm was developed to combine the inertial and wind velocities to provide an estimate of the aircraft's current true velocity to be used for command path gain scheduling and for display in the cockpit...

  8. Evolution of Seismic Velocities in Heavy Oil Sand Reservoirs during Thermal Recovery Process Évolution des vitesses sismiques dans les réservoirs de sables bitumineux au cours des procédés de récupération thermique

    Directory of Open Access Journals (Sweden)

    Nauroy J.-F.

    2013-01-01

    Full Text Available In thermally enhanced recovery processes like Cyclic Steam Stimulation (CSS or Steam Assisted Gravity Drainage (SAGD, continuous steam injection entails changes in pore fluid, pore pressure and temperature in the rock reservoir, that are most often unconsolidated or weakly consolidated sandstones. This in turn increases or decreases the effective stresses and changes the elastic properties of the rocks. Thermally enhanced recovery processes give rise to complex couplings. 4D seismic surveys are currently conducted to delineate the steam-affected areas but the interpretation is difficult. However, it is essential for optimization of reservoir development. Numerical simulations have been carried out on a case study so as to provide an estimation of the evolution of pressure, temperature, pore fluid saturation, stress and strain in any zone located around the injector and producer wells. The approach of Ciz and Shapiro (2007 (Geophysics 72, A75-A79 has been used to model the velocity dispersion in the oil sand mass under different conditions of temperature and stress. A good agreement has been found between these predictions and some laboratory velocity measurements carried out on samples of Canadian oil sand. Results appear to be useful to better interpret 4D seismic data in order to locate the steam chamber. Dans les procédés de récupération des huiles lourdes par méthodes thermiques, comme ia stimulation cyclique par vapeur (CSS ou le drainage par gravité assisté par vapeur (SAGD, l’injection de vapeur en continu entraîne des changements de liquide de pores, de pression interstitielle et de température dans la roche réservoir, qui est constituée le plus souvent de sable non consolidés ou faiblement consolidés- Ces changements à leur tour augmentent ou diminuent les contraintes effectives et modifient les propriétés élastiques des roches. Les procédés de récupération par méthodes thermiques mettent en oeuvre des couplages

  9. Cosmic string induced peculiar velocities

    International Nuclear Information System (INIS)

    van Dalen, A.; Schramm, D.N.

    1987-02-01

    We calculate analytically the probability distribution for peculiar velocities on scales from 10h -1 to 60h -1 Mpc with cosmic string loops as the dominant source of primordial gravitational perturbations. We consider a range of parameters βGμ appropriate for both hot (HDM) and cold (CDM) dark matter scenarios. An Ω = 1 CDM Universe is assumed with the loops randomly placed on a smooth background. It is shown how the effects can be estimated of loops breaking up and being born with a spectrum of sizes. It is found that to obtain large scale streaming velocities of at least 400 km/s it is necessary that either a large value for βGμ or the effect of loop fissioning and production details be considerable. Specifically, for optimal CDM string parameters Gμ = 10 -6 , β = 9, h = .5, and scales of 60h -1 Mpc, the parent size spectrum must be 36 times larger than the evolved daughter spectrum to achieve peculiar velocities of at least 400 km/s with a probability of 63%. With this scenario the microwave background dipole will be less than 800 km/s with only a 10% probability. The string induced velocity spectrum is relatively flat out to scales of about 2t/sub eq//a/sub eq/ and then drops off rather quickly. The flatness is a signature of string models of galaxy formation. With HDM a larger value of βGμ is necessary for galaxy formation since accretion on small scales starts later. Hence, with HDM, the peculiar velocity spectrum will be larger on large scales and the flat region will extend to larger scales. If large scale peculiar velocities greater than 400 km/s are real then it is concluded that strings plus CDM have difficulties. The advantages of strings plus HDM in this regard will be explored in greater detail in a later paper. 27 refs., 4 figs., 1 tab

  10. Angle independent velocity spectrum determination

    DEFF Research Database (Denmark)

    2014-01-01

    An ultrasound imaging system (100) includes a transducer array (102) that emits an ultrasound beam and produces at least one transverse pulse-echo field that oscillates in a direction transverse to the emitted ultrasound beam and that receive echoes produced in response thereto and a spectral vel...... velocity estimator (110) that determines a velocity spectrum for flowing structure, which flows at an angle of 90 degrees and flows at angles less than 90 degrees with respect to the emitted ultrasound beam, based on the received echoes....

  11. Searching for the Expelled Hydrogen Envelope in Type I Supernovae via Late-Time H α Emission

    Energy Technology Data Exchange (ETDEWEB)

    Vinko, J.; Silverman, J. M.; Wheeler, J. C.; MacQueen, P.; Marion, G. H. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Pooley, D. [Department of Physics and Astronomy, Trinity University, One Trinity Place, San Antonio, TX 78212 (United States); Szalai, T. [Department of Optics and Quantum Electronics, University of Szeged, Dom ter 9, Szeged, 6720 (Hungary); Kelly, P. [Department of Astronomy, University of California at Berkeley, 501 Campbell Hall, Berkeley, CA 94720-3411 (United States); Sárneczky, K. [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege ut 15-17, Budapest, 1121 (Hungary)

    2017-03-01

    We report the first results from our long-term observational survey aimed at discovering late-time interaction between the ejecta of hydrogen-poor Type I supernovae (SNe I) and the hydrogen-rich envelope expelled from the progenitor star several decades/centuries before explosion. The expelled envelope, moving with a velocity of ∼10–100 km s{sup −1}, is expected to be caught up by the fast-moving SN ejecta several years/decades after explosion, depending on the history of the mass-loss process acting in the progenitor star prior to explosion. The collision between the SN ejecta and the circumstellar envelope results in net emission in the Balmer lines, especially H α . We look for signs of late-time H α emission in older SNe Ia/Ibc/IIb with hydrogen-poor ejecta via narrowband imaging. Continuum-subtracted H α emission has been detected for 13 point sources: 9 SN Ibc, 1 SN IIb, and 3 SN Ia events. Thirty-eight SN sites were observed on at least two epochs, from which three objects (SN 1985F, SN 2005kl, and SN 2012fh) showed significant temporal variation in the strength of their H α emission in our Direct Imaging Auxiliary Functions Instrument (DIAFI) data. This suggests that the variable emission is probably not due to nearby H ii regions unassociated with the SN and hence is an important additional hint that ejecta–circumstellar medium interaction may take place in these systems. Moreover, we successfully detected the late-time H α emission from the Type Ib SN 2014C, which was recently discovered as a strongly interacting SN in various (radio, infrared, optical, and X-ray) bands.

  12. Numerical calculation of air velocity and temperature in ice rinks

    Energy Technology Data Exchange (ETDEWEB)

    Bellache, O.; Galanis, N. [Sherbrooke Univ., PQ (Canada); Ouzzane, M.; Sunye, R. [Natural Resources Canada, Varennes, PQ (Canada). CANMET Energy Diversification Laboratory

    2002-07-01

    A computational fluid dynamic (CFD) model was developed to predict the energy consumption at an ice rink. Ice rinks in Canada consume approximately 3500 GWh of electricity annually and generate about 300,000 tons of gases contributing to the greenhouse effect. This newly developed model also considers ice quality and comfort conditions in the arena. The typical 2D configuration includes refrigeration loads as well as heat transfer coefficients between the air and the ice. The effects of heat losses through the ice rink envelope are also determined. A comparison of prediction results from 4 different formulations confirms that there are important differences in air velocities near the walls and in the temperature gradient near the ice. The turbulent mixed convection model gives the best estimate of the refrigeration load. It was determined that a good ventilation should circulate air throughout the building to avoid stagnant areas. Air velocities must be low near the stands where the temperature should be around 20 degrees C. Air temperature near the ice should be low to preserve ice quality and to reduce the refrigeration load. The complexity of this geometry has been taken into account in a numerical simulation of the hydrodynamic and thermal fields in the ice rink. 9 refs., 2 tabs., 5 figs.

  13. ROTATIONAL VELOCITIES FOR M DWARFS

    International Nuclear Information System (INIS)

    Jenkins, J. S.; Ramsey, L. W.; Jones, H. R. A.; Pavlenko, Y.; Barnes, J. R.; Pinfield, D. J.; Gallardo, J.

    2009-01-01

    We present spectroscopic rotation velocities (v sin i) for 56 M dwarf stars using high-resolution Hobby-Eberly Telescope High Resolution Spectrograph red spectroscopy. In addition, we have also determined photometric effective temperatures, masses, and metallicities ([Fe/H]) for some stars observed here and in the literature where we could acquire accurate parallax measurements and relevant photometry. We have increased the number of known v sin i values for mid M stars by around 80% and can confirm a weakly increasing rotation velocity with decreasing effective temperature. Our sample of v sin is peak at low velocities (∼3 km s -1 ). We find a change in the rotational velocity distribution between early M and late M stars, which is likely due to the changing field topology between partially and fully convective stars. There is also a possible further change in the rotational distribution toward the late M dwarfs where dust begins to play a role in the stellar atmospheres. We also link v sin i to age and show how it can be used to provide mid-M star age limits. When all literature velocities for M dwarfs are added to our sample, there are 198 with v sin i ≤ 10 km s -1 and 124 in the mid-to-late M star regime (M3.0-M9.5) where measuring precision optical radial velocities is difficult. In addition, we also search the spectra for any significant Hα emission or absorption. Forty three percent were found to exhibit such emission and could represent young, active objects with high levels of radial-velocity noise. We acquired two epochs of spectra for the star GJ1253 spread by almost one month and the Hα profile changed from showing no clear signs of emission, to exhibiting a clear emission peak. Four stars in our sample appear to be low-mass binaries (GJ1080, GJ3129, Gl802, and LHS3080), with both GJ3129 and Gl802 exhibiting double Hα emission features. The tables presented here will aid any future M star planet search target selection to extract stars with low v

  14. A RADIAL VELOCITY STUDY OF COMPOSITE-SPECTRA HOT SUBDWARF STARS WITH THE HOBBY-EBERLY TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Barlow, Brad N.; Wade, Richard A.; Liss, Sandra E. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Ostensen, Roy H.; Van Winckel, Hans [Instituut voor Sterrenkunde, K.U. Leuven, B-3001 Leuven (Belgium)

    2012-10-10

    Many hot subdwarf stars show composite spectral energy distributions indicative of cool main-sequence (MS) companions. Binary population synthesis (BPS) models demonstrate such systems can be formed via Roche lobe overflow or common envelope evolution but disagree on whether the resulting orbital periods will be long (years) or short (days). Few studies have been carried out to assess the orbital parameters of these spectroscopic composite binaries; current observations suggest the periods are long. To help address this problem, we selected 15 moderately bright (V {approx} 13) hot subdwarfs with F-K dwarf companions and monitored their radial velocities from 2005 January to 2008 July using the bench-mounted Medium Resolution Spectrograph on the Hobby-Eberly Telescope (HET). Here we describe the details of our observing, reduction, and analysis techniques, and present preliminary results for all targets. By combining the HET data with recent observations from the Mercator Telescope, we are able to calculate precise orbital solutions for three systems using more than six years of observations. We also present an up-to-date period histogram for all known hot subdwarf binaries, which suggests those with F-K MS companions tend to have orbital periods on the order of several years. Such long periods challenge the predictions of conventional BPS models, although a larger sample is needed for a thorough assessment of the models' predictive success. Lastly, one of our targets has an eccentric orbit, implying some composite-spectrum systems might have formerly been hierarchical triple systems, in which the inner binary merged to create the hot subdwarf.

  15. Biliary Secretion of Quasi-Enveloped Human Hepatitis A Virus

    Directory of Open Access Journals (Sweden)

    Asuka Hirai-Yuki

    2016-12-01

    Full Text Available Hepatitis A virus (HAV is an unusual picornavirus that is released from cells cloaked in host-derived membranes. These quasi-enveloped virions (eHAV are the only particle type circulating in blood during infection, whereas only nonenveloped virions are shed in feces. The reason for this is uncertain. Hepatocytes, the only cell type known to support HAV replication in vivo, are highly polarized epithelial cells with basolateral membranes facing onto hepatic (blood sinusoids and apical membranes abutting biliary canaliculi from which bile is secreted to the gut. To assess whether eHAV and nonenveloped virus egress from cells via vectorially distinct pathways, we studied infected polarized cultures of Caco-2 and HepG2-N6 cells. Most (>99% progeny virions were released apically from Caco-2 cells, whereas basolateral (64% versus apical (36% release was more balanced with HepG2-N6 cells. Both apically and basolaterally released virions were predominantly enveloped, with no suggestion of differential vectorial release of eHAV versus naked virions. Basolateral to apical transcytosis of either particle type was minimal (<0.02%/h in HepG2-N6 cells, arguing against this as a mechanism for differences in membrane envelopment of serum versus fecal virus. High concentrations of human bile acids converted eHAV to nonenveloped virions, whereas virus present in bile from HAV-infected Ifnar1−/−Ifngr1−/− and Mavs−/− mice banded over a range of densities extending from that of eHAV to that of nonenveloped virions. We conclude that nonenveloped virions shed in feces are derived from eHAV released across the canalicular membrane and stripped of membranes by the detergent action of bile acids within the proximal biliary canaliculus.

  16. Energy Optimized Envelope for Cold Climate Indoor Agricultural Growing Center

    Directory of Open Access Journals (Sweden)

    Caroline Hachem-Vermette

    2017-07-01

    Full Text Available This paper presents a study of the development of building envelope design for improved energy performance of a controlled indoor agricultural growing center in a cold climate zone (Canada, 54° N. A parametric study is applied to analyze the effects of envelope parameters on the building energy loads for heating, cooling and lighting, required for maintaining growing requirement as obtained in the literature. A base case building of rectangular layout, incorporating conventionally applied insulation and glazing components, is initially analyzed, employing the EnergyPlus simulation program. Insulation and glazing parameters are then modified to minimize energy loads under assumed minimal lighting requirement. This enhanced design forms a base case for analyzing effects of additional design parameters—solar radiation control, air infiltration rate, sky-lighting and the addition of phase change materials—to obtain an enhanced design that minimizes energy loads. A second stage of the investigation applies a high lighting level to the enhanced design and modifies the design parameters to improve performance. A final part of the study is an investigation of the mechanical systems and renewable energy generation. Through the enhancement of building envelope components and day-lighting design, combined heating and cooling load of the low level lighting configuration is reduced by 65% and lighting load by 10%, relative to the base case design. Employing building integrated PV (BIPV system, this optimized model can achieve energy positive status. Solid Oxide Fuel Cells (SOFC, are discussed, as potential means to offset increased energy consumption associated with the high-level lighting model.

  17. Nuclear envelopathies: a complex LINC between nuclear envelope and pathology.

    Science.gov (United States)

    Janin, Alexandre; Bauer, Delphine; Ratti, Francesca; Millat, Gilles; Méjat, Alexandre

    2017-08-30

    Since the identification of the first disease causing mutation in the gene coding for emerin, a transmembrane protein of the inner nuclear membrane, hundreds of mutations and variants have been found in genes encoding for nuclear envelope components. These proteins can be part of the inner nuclear membrane (INM), such as emerin or SUN proteins, outer nuclear membrane (ONM), such as Nesprins, or the nuclear lamina, such as lamins A and C. However, they physically interact with each other to insure the nuclear envelope integrity and mediate the interactions of the nuclear envelope with both the genome, on the inner side, and the cytoskeleton, on the outer side. The core of this complex, called LINC (LInker of Nucleoskeleton to Cytoskeleton) is composed of KASH and SUN homology domain proteins. SUN proteins are INM proteins which interact with lamins by their N-terminal domain and with the KASH domain of nesprins located in the ONM by their C-terminal domain.Although most of these proteins are ubiquitously expressed, their mutations have been associated with a large number of clinically unrelated pathologies affecting specific tissues. Moreover, variants in SUN proteins have been found to modulate the severity of diseases induced by mutations in other LINC components or interactors. For these reasons, the diagnosis and the identification of the molecular explanation of "nuclear envelopathies" is currently challenging.The aim of this review is to summarize the human diseases caused by mutations in genes coding for INM proteins, nuclear lamina, and ONM proteins, and to discuss their potential physiopathological mechanisms that could explain the large spectrum of observed symptoms.

  18. Dynamic network data envelopment analysis for university hospitals evaluation

    Directory of Open Access Journals (Sweden)

    Maria Stella de Castro Lobo

    2016-01-01

    Full Text Available ABSTRACT OBJECTIVE To develop an assessment tool to evaluate the efficiency of federal university general hospitals. METHODS Data envelopment analysis, a linear programming technique, creates a best practice frontier by comparing observed production given the amount of resources used. The model is output-oriented and considers variable returns to scale. Network data envelopment analysis considers link variables belonging to more than one dimension (in the model, medical residents, adjusted admissions, and research projects. Dynamic network data envelopment analysis uses carry-over variables (in the model, financing budget to analyze frontier shift in subsequent years. Data were gathered from the information system of the Brazilian Ministry of Education (MEC, 2010-2013. RESULTS The mean scores for health care, teaching and research over the period were 58.0%, 86.0%, and 61.0%, respectively. In 2012, the best performance year, for all units to reach the frontier it would be necessary to have a mean increase of 65.0% in outpatient visits; 34.0% in admissions; 12.0% in undergraduate students; 13.0% in multi-professional residents; 48.0% in graduate students; 7.0% in research projects; besides a decrease of 9.0% in medical residents. In the same year, an increase of 0.9% in financing budget would be necessary to improve the care output frontier. In the dynamic evaluation, there was progress in teaching efficiency, oscillation in medical care and no variation in research. CONCLUSIONS The proposed model generates public health planning and programming parameters by estimating efficiency scores and making projections to reach the best practice frontier.

  19. Characteristics between the meshing pairs with different envelope profile in single screw compressors

    Science.gov (United States)

    Huang, R.; Liu, F.; Li, T.; Feng, Q.

    2017-08-01

    Single screw compressors have been used in various industrial fields. However, because the star-wheel teeth are easy to wear, the market for the development of single screw compressors is limited. In order to extend the service life of the star-wheel, researchers have developed different kinds of star-wheel tooth profile, such as single line envelope profile, single column envelope profile, and multi-column envelope profile. These profiles greatly affect the lubrication characteristics between the star-wheel teeth and the screw grooves. In this article, the lubrication characteristics between the meshing pairs with different envelope profiles are analyzed. Results show that the pressure peak of the single line envelope profile, single column envelope profile, and multi-column envelope profile are 3.23×105Pa, 3.38×105Pa, and 4.31×105Pa, respectively. This means that the multi-column enveloped meshing pair can resist the biggest external impact load. The deviation angle (γ) of the single line envelope profile, single column envelope profile, and multi-column envelope profile are 0.0139°~0.0286°, 0.0225°~0.0306° and 0.0122°~0.0262°, respectively. Thus, the self-balancing ability of the multi-column enveloped meshing pair is the strongest, and the oil film thickness on both sides of the multi-column enveloped star-wheel tooth is the most reasonable, which indicates a good lubrication state during operation, that is, longer operation life of the star-wheel teeth.

  20. Si-BEARING MOLECULES TOWARD IRC+10216: ALMA UNVEILS THE MOLECULAR ENVELOPE OF CWLeo

    International Nuclear Information System (INIS)

    Prieto, L. Velilla; Cernicharo, J.; Quintana-Lacaci, G.; Agúndez, M.; Castro-Carrizo, A.; Guélin, M.; Fonfría, J. P.; Marcelino, N.; Zúñiga, J.; Requena, A.; Bastida, A.; Lique, F.

    2015-01-01

    We report the detection of SiS rotational lines in high-vibrational states as well as SiO and SiC 2 lines in their ground vibrational state toward IRC+10216 during the Atacama Large Millimeter Array Cycle 0. The spatial distribution of these molecules shows compact emission for SiS and a more extended emission for SiO and SiC 2 and also proves the existence of an increase in the SiC 2 emission at the outer shells of the circumstellar envelope (CSE). We analyze the excitation conditions of the vibrationally excited SiS using the population diagram technique, and we use a large velocity gradient model to compare with the observations. We found moderate discrepancies between the observations and the models that could be explained if SiS lines detected are optically thick. Additionally, the line profiles of the detected rotational lines in the high-energy vibrational states show a decreasing linewidth with increasing energy levels. This may be evidence that these lines could be excited only in the inner shells, i.e., the densest and hottest, of the CSE of IRC+10216

  1. Arcsecond Resolution Mapping of Sulfur Dioxide Emission in the Circumstellar Envelope of VY Canis Majoris

    Science.gov (United States)

    Fu, Roger R.; Moullet, Arielle; Patel, Nimesh A.; Biersteker, John; Derose, Kimberly L.; Young, Kenneth H.

    2012-02-01

    We report Submillimeter Array observations of SO2 emission in the circumstellar envelope (CSE) of the red supergiant VY Canis Majoris, with an angular resolution of ≈1''. SO2 emission appears in three distinct outflow regions surrounding the central continuum peak emission that is spatially unresolved. No bipolar structure is noted in the sources. A fourth source of SO2 is identified as a spherical wind centered at the systemic velocity. We estimate the SO2 column density and rotational temperature assuming local thermal equilibrium (LTE) as well as perform non-LTE radiative transfer analysis using RADEX. Column densities of SO2 are found to be ~1016 cm-2 in the outflows and in the spherical wind. Comparison with existing maps of the two parent species OH and SO shows the SO2 distribution to be consistent with that of OH. The abundance ratio f_{SO_{2}}/f_{SO} is greater than unity for all radii larger than 3 × 1016 cm. SO2 is distributed in fragmented clumps compared to SO, PN, and SiS molecules. These observations lend support to specific models of circumstellar chemistry that predict f_{SO_{2}}/f_{SO}>1 and may suggest the role of localized effects such as shocks in the production of SO2 in the CSE.

  2. ARCSECOND RESOLUTION MAPPING OF SULFUR DIOXIDE EMISSION IN THE CIRCUMSTELLAR ENVELOPE OF VY CANIS MAJORIS

    International Nuclear Information System (INIS)

    Fu, Roger R.; Moullet, Arielle; Patel, Nimesh A.; Biersteker, John; Derose, Kimberly L.; Young, Kenneth H.

    2012-01-01

    We report Submillimeter Array observations of SO 2 emission in the circumstellar envelope (CSE) of the red supergiant VY Canis Majoris, with an angular resolution of ≈1''. SO 2 emission appears in three distinct outflow regions surrounding the central continuum peak emission that is spatially unresolved. No bipolar structure is noted in the sources. A fourth source of SO 2 is identified as a spherical wind centered at the systemic velocity. We estimate the SO 2 column density and rotational temperature assuming local thermal equilibrium (LTE) as well as perform non-LTE radiative transfer analysis using RADEX. Column densities of SO 2 are found to be ∼10 16 cm –2 in the outflows and in the spherical wind. Comparison with existing maps of the two parent species OH and SO shows the SO 2 distribution to be consistent with that of OH. The abundance ratio f SO 2 /f SO is greater than unity for all radii larger than 3 × 10 16 cm. SO 2 is distributed in fragmented clumps compared to SO, PN, and SiS molecules. These observations lend support to specific models of circumstellar chemistry that predict f SO 2 /f SO >1 and may suggest the role of localized effects such as shocks in the production of SO 2 in the CSE.

  3. Expanded envelope concepts for aircraft control-element failure detection and identification

    Science.gov (United States)

    Weiss, Jerold L.; Hsu, John Y.

    1988-01-01

    The purpose of this effort was to develop and demonstrate concepts for expanding the envelope of failure detection and isolation (FDI) algorithms for aircraft-path failures. An algorithm which uses analytic-redundancy in the form of aerodynamic force and moment balance equations was used. Because aircraft-path FDI uses analytical models, there is a tradeoff between accuracy and the ability to detect and isolate failures. For single flight condition operation, design and analysis methods are developed to deal with this robustness problem. When the departure from the single flight condition is significant, algorithm adaptation is necessary. Adaptation requirements for the residual generation portion of the FDI algorithm are interpreted as the need for accurate, large-motion aero-models, over a broad range of velocity and altitude conditions. For the decision-making part of the algorithm, adaptation may require modifications to filtering operations, thresholds, and projection vectors that define the various hypothesis tests performed in the decision mechanism. Methods of obtaining and evaluating adequate residual generation and decision-making designs have been developed. The application of the residual generation ideas to a high-performance fighter is demonstrated by developing adaptive residuals for the AFTI-F-16 and simulating their behavior under a variety of maneuvers using the results of a NASA F-16 simulation.

  4. A smart growth evaluation model based on data envelopment analysis

    Science.gov (United States)

    Zhang, Xiaokun; Guan, Yongyi

    2018-04-01

    With the rapid spread of urbanization, smart growth (SG) has attracted plenty of attention from all over the world. In this paper, by the establishment of index system for smart growth, data envelopment analysis (DEA) model was suggested to evaluate the SG level of the current growth situation in cities. In order to further improve the information of both radial direction and non-radial detection, we introduced the non-Archimedean infinitesimal to form C2GS2 control model. Finally, we evaluated the SG level in Canberra and identified a series of problems, which can verify the applicability of the model and provide us more improvement information.

  5. Thermonuclear runaways in thick hydrogen rich envelopes of neutron stars

    Science.gov (United States)

    Starrfield, S. G.; Kenyon, S.; Truran, J. W.; Sparks, W. M.

    1981-01-01

    A Lagrangian, fully implicit, one dimensional hydrodynamic computer code was used to evolve thermonuclear runaways in the accreted hydrogen rich envelopes of 1.0 Msub solar neutron stars with radii of 10 km and 20 km. Simulations produce outbursts which last from about 750 seconds to about one week. Peak effective temeratures and luninosities were 26 million K and 80 thousand Lsub solar for the 10 km study and 5.3 millison and 600 Lsub solar for the 20 km study. Hydrodynamic expansion on the 10 km neutron star produced a precursor lasting about one ten thousandth seconds.

  6. Multinodal control room envelope model used for habitability analysis

    International Nuclear Information System (INIS)

    Blumberg, W.M.; Gore, D.E.

    1995-01-01

    This work analyzes the habitability of the control room envelope (CRE) during an off-normal ventilation system condition. The most limiting design basis accident utilized for this analysis is the postulated loss-of-coolant accident. The off-normal condition assumes two rooms within the CRE are at pressures that are lower than adjoining rooms outside the CRE. This pressure differential allows unfiltered in-leakage to enter the CRE through the doors and penetrations in these rooms. This paper quantifies the maximum unfiltered in-leakage

  7. The Data Envelopment Analysis Method in Benchmarking of Technological Incubators

    Directory of Open Access Journals (Sweden)

    Bożena Kaczmarska

    2010-01-01

    Full Text Available This paper presents an original concept for the application of Data Envelopment Analysis (DEA in benchmarking processes within innovation and entrepreneurship centers based on the example of technological incubators. Applying the DEA method, it is possible to order analyzed objects, on the basis of explicitly defined relative efficiency, by compiling a rating list and rating classes. Establishing standards and indicating “clearances” allows the studied objects - innovation and entrepreneurship centers - to select a way of developing effectively, as well as preserving their individuality and a unique way of acting with the account of local needs. (original abstract

  8. Biliary Secretion of Quasi-Enveloped Human Hepatitis A Virus.

    Science.gov (United States)

    Hirai-Yuki, Asuka; Hensley, Lucinda; Whitmire, Jason K; Lemon, Stanley M

    2016-12-06

    Hepatitis A virus (HAV) is an unusual picornavirus that is released from cells cloaked in host-derived membranes. These quasi-enveloped virions (eHAV) are the only particle type circulating in blood during infection, whereas only nonenveloped virions are shed in feces. The reason for this is uncertain. Hepatocytes, the only cell type known to support HAV replication in vivo, are highly polarized epithelial cells with basolateral membranes facing onto hepatic (blood) sinusoids and apical membranes abutting biliary canaliculi from which bile is secreted to the gut. To assess whether eHAV and nonenveloped virus egress from cells via vectorially distinct pathways, we studied infected polarized cultures of Caco-2 and HepG2-N6 cells. Most (>99%) progeny virions were released apically from Caco-2 cells, whereas basolateral (64%) versus apical (36%) release was more balanced with HepG2-N6 cells. Both apically and basolaterally released virions were predominantly enveloped, with no suggestion of differential vectorial release of eHAV versus naked virions. Basolateral to apical transcytosis of either particle type was minimal (work reveals that it has an unusual life cycle. Virus is found in cell culture supernatant fluids in two mature, infectious forms: one wrapped in membranes (quasi-enveloped) and another that is nonenveloped. Membrane-wrapped virions circulate in blood during acute infection and are resistant to neutralizing antibodies, likely facilitating HAV dissemination within the liver. On the other hand, virus shed in feces is nonenveloped and highly stable, facilitating epidemic spread and transmission to naive hosts. Factors controlling the biogenesis of these two distinct forms of the virus in infected humans are not understood. Here we characterize vectorial release of quasi-enveloped virions from polarized epithelial cell cultures and provide evidence that bile acids strip membranes from eHAV following its secretion into the biliary tract. These results

  9. Towards a fourth skin? sustainability and double-envelope buildings

    Energy Technology Data Exchange (ETDEWEB)

    Diprose, P.R.; Robertson, G. [Auckland Univ. (New Zealand)

    1996-05-01

    In several well publicised designs for `green` office buildings, the zone of meditation between inside and outside has been increased by the addition of a second building envelope. When interpreted as exemplars of sustainable architecture, the addition of a second wall in these buildings is questionable both biophysically and psycho-culturally. More constructive design strategies acknowledge the wider biophysical contexts of the human ecosystem, the prudent use of material and energy resources throughout a building`s life, make realistic use of climate, and promote psycho-cultural needs arising out of ecologism. (author)

  10. Assessing Canadian Bank Branch Operating Efficiency Using Data Envelopment Analysis

    Science.gov (United States)

    Yang, Zijiang

    2009-10-01

    In today's economy and society, performance analyses in the services industries attract more and more attention. This paper presents an evaluation of 240 branches of one big Canadian bank in Greater Toronto Area using Data Envelopment Analysis (DEA). Special emphasis was placed on how to present the DEA results to management so as to provide more guidance to them on what to manage and how to accomplish the changes. Finally the potential management uses of the DEA results were presented. All the findings are discussed in the context of the Canadian banking market.

  11. Radiation-induced invagination of the nuclear envelope

    International Nuclear Information System (INIS)

    Szekely, J.G.; Copps, T.P.; Morash, B.D.

    1980-01-01

    Using electron microscopy, we have measured radiation-induced invagination of the nuclear envelope of Chinese hamster V-79 and mouse L cells to produce a quantifiable radiation endpoint on a membrane system. In the dose ranges measured (800 to 3000 rad in L cells and 1270 to 5700 rad in V-79 cells), the amount of invagination increased with dose and continued to develop in intact cells for up to 72 hr after the original population was irradiated. Small vacuoles, which sometimes appeared in the nuclei of L cells, were also more numerous in irradiated cells and increased with dose and incubation time in a similar fashion to invagination development

  12. A competitive-inhibiton radioimmunoassay for influenza virus envelope antigens

    International Nuclear Information System (INIS)

    Russ, G.; Styk, B.; Vareckova, E.; Polakova, K.

    1976-01-01

    A double-antibody competitive-inhibition radioimmunoassay for influenza virus envelope antigens is described. A viral antigen preparation from influenza A virus recombinant MRC11 [antigenically identical to A/Port Chalmers/1/73 (H3N2)] consisting of haemagglutinin and neuraminidase was labelled with radioiodine. Rabbit antisera were allowed to react with the labelled antigen and the resultant antigen-antibody complexes were precipitated with the appropriate antiglobulin. The competitive-inhibition radioimmunoassay very sensitively elucidated differences even among closely related influenza virus strains. Attempts have been made to eliminate neuraminidase from radioimmunoprecipitation to obtain a competitive-inhibition radioimmunoassay system for haemagglutinin alone. (author)

  13. Optimizing velocities and transports for complex coastal regions and archipelagos

    Science.gov (United States)

    Haley, Patrick J.; Agarwal, Arpit; Lermusiaux, Pierre F. J.

    2015-05-01

    We derive and apply a methodology for the initialization of velocity and transport fields in complex multiply-connected regions with multiscale dynamics. The result is initial fields that are consistent with observations, complex geometry and dynamics, and that can simulate the evolution of ocean processes without large spurious initial transients. A class of constrained weighted least squares optimizations is defined to best fit first-guess velocities while satisfying the complex bathymetry, coastline and divergence strong constraints. A weak constraint towards the minimum inter-island transports that are in accord with the first-guess velocities provides important velocity corrections in complex archipelagos. In the optimization weights, the minimum distance and vertical area between pairs of coasts are computed using a Fast Marching Method. Additional information on velocity and transports are included as strong or weak constraints. We apply our methodology around the Hawaiian islands of Kauai/Niihau, in the Taiwan/Kuroshio region and in the Philippines Archipelago. Comparisons with other common initialization strategies, among hindcasts from these initial conditions (ICs), and with independent in situ observations show that our optimization corrects transports, satisfies boundary conditions and redirects currents. Differences between the hindcasts from these different ICs are found to grow for at least 2-3 weeks. When compared to independent in situ observations, simulations from our optimized ICs are shown to have the smallest errors.

  14. Precollisional velocity correlations in a hard-disk fluid with dissipative collisions.

    Science.gov (United States)

    Soto, R; Piasecki, J; Mareschal, M

    2001-09-01

    Velocity correlations are studied in granular fluids, modeled by the inelastic hard sphere gas. Making a density expansion of the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy for the evolution of the reduced distributions, we predict the presence of precollisional velocity correlations. They are created by the propagation through correlated sequences of collisions (ring events) of the velocity correlations generated after dissipative collisions. The correlations have their origin in the dissipative character of collisions, being always present in granular fluids. The correlations, that manifest microscopically as an alignment of the velocities of a colliding pair produce modifications of collisional averages, in particular, the virial pressure. The pressure shows a reduction with respect to the elastic case as a consequence of the velocity alignment. Good qualitative agreement is obtained for the comparison of the numerical evaluations of the obtained analytical expressions and molecular dynamics results that showed evidence of precollisional velocity correlations [R. Soto and M. Mareschal, Phys. Rev. E 63, 041303 (2001)].

  15. A new insight into opaque envelopes in a passive solar house: Properties and roles

    International Nuclear Information System (INIS)

    Long, Linshuang; Ye, Hong; Liu, Minghou

    2016-01-01

    Highlights: • A new insight into the opaque envelopes of a passive solar house was gained. • Five parts of envelopes, i.e., roof, south/east/west/north walls, were discussed. • Each part of envelopes were analyzed separately rather than treated as a whole. • Ideal properties of materials for each envelope are diverse from one another. • Differences are related to the envelopes’ leading roles as a heater or a cooler. - Abstract: Passive solar houses are effective solutions for minimizing the operating energy of buildings. The building envelopes of passive solar houses exert a significant influence on the degree of indoor thermal comfort. The focus of this study was the construction of high-performance opaque envelopes, i.e., the roof and walls, for a passive solar house, and a new conception of the envelopes from the perspective of the relation between the properties and roles was provided. The discussion was conducted based on a comprehensive range of envelope materials that were distinguished by the thermal conductivity and volumetric heat capacity. For the first time, each part of the envelopes was analyzed separately rather than considered as an entire envelope. By analyzing each envelope individually, the optimum properties of each envelope were found to be distinct from each other. The distinctions are determined by the dominant role of each envelope, which is associated with the location and absorbed solar irradiation. For summer or hot climate applications, when the dominant role is a cooler, the envelope, e.g., the south wall, should consist of materials with high thermal conductivity and large heat capacity; if a heater is the dominant role, the envelope, e.g., the roof, should consist of materials with low thermal conductivity. For winter or cold climate applications, the envelopes with a leading role of a heater or a cooler require materials with high or low thermal conductivity, respectively. Under the guidance of the results, a discussion

  16. Schumpeter's Evolution

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    reworking of his basic theory of economic evolution in Development from 1934, and this reworking was continued in Cycles from 1939. Here Schumpeter also tried to handle the statistical and historical evidence on the waveform evolution of the capitalist economy. Capitalism from 1942 modified the model...

  17. Galactic evolution

    International Nuclear Information System (INIS)

    Pagel, B.

    1979-01-01

    Ideas are considered concerning the evolution of galaxies which are closely related to those of stellar evolution and the origin of elements. Using information obtained from stellar spectra, astronomers are now able to consider an underlying process to explain the distribution of various elements in the stars, gas and dust clouds of the galaxies. (U.K.)

  18. Darwinian evolution

    NARCIS (Netherlands)

    Jagers op Akkerhuis, Gerard A.J.M.; Spijkerboer, Hendrik Pieter; Koelewijn, Hans Peter

    2016-01-01

    Darwinian evolution is a central tenet in biology. Conventionally, the defi nition of Darwinian evolution is linked to a population-based process that can be measured by focusing on changes in DNA/allele frequencies. However, in some publications it has been suggested that selection represents a

  19. Sulfur chemistry in the envelope of VY Canis Majoris: Detailed analysis of SO and SO2 emission

    International Nuclear Information System (INIS)

    Adande, G. R.; Edwards, J. L.; Ziurys, L. M.

    2013-01-01

    Detailed radiative transfer modeling has been carried out for SO 2 and SO originating in the envelope of the O-rich supergiant star VY Canis Majoris (VY CMa). A total of 27 transitions of SO 2 and 7 transitions of SO lying in the energy range 3.0-138.2 cm –1 were analyzed using a new non-LTE radiative transfer code that incorporates non-spherical geometries. The spectra were primarily obtained from the Arizona Radio Observatory (ARO) 1 mm spectral survey of VY CMa, conducted with the Submillimeter Telescope; additional lines were measured with the ARO 12 m antenna at 2 and 3 mm. SO 2 and SO were found to arise from five distinct outflows within the envelope, four which are asymmetric with respect to the star. Three flows arise from high-velocity red-shifted material, one from a blue-shifted wind, and the final from a classic 'spherical' expansion. In the spherical component, the peak fractional abundance, relative to H 2 , of both molecules is f ∼ 2.5 × 10 –7 at r ∼ 25 R * , and steadily decreases outward. SO 2 appears to be a 'parent' molecule, formed near the stellar photosphere. In the asymmetric outflows, both SO and SO 2 are more prominent at large stellar radii in dense (10 6 -10 7 cm –3 ), clumpy material, achieving their maximum abundance between 200 and 600 R * with f ∼ 3.0 × 10 –8 -1.5 × 10 –7 . These results suggest that in the collimated outflows, both species are either produced by shock chemistry or are remnant inner shell material swept up in the high-velocity winds.

  20. Sulfur Chemistry in the Envelope of VY Canis Majoris: Detailed Analysis of SO and SO2 Emission

    Science.gov (United States)

    Adande, G. R.; Edwards, J. L.; Ziurys, L. M.

    2013-11-01

    Detailed radiative transfer modeling has been carried out for SO2 and SO originating in the envelope of the O-rich supergiant star VY Canis Majoris (VY CMa). A total of 27 transitions of SO2 and 7 transitions of SO lying in the energy range 3.0-138.2 cm-1 were analyzed using a new non-LTE radiative transfer code that incorporates non-spherical geometries. The spectra were primarily obtained from the Arizona Radio Observatory (ARO) 1 mm spectral survey of VY CMa, conducted with the Submillimeter Telescope; additional lines were measured with the ARO 12 m antenna at 2 and 3 mm. SO2 and SO were found to arise from five distinct outflows within the envelope, four which are asymmetric with respect to the star. Three flows arise from high-velocity red-shifted material, one from a blue-shifted wind, and the final from a classic "spherical" expansion. In the spherical component, the peak fractional abundance, relative to H2, of both molecules is f ~ 2.5 × 10-7 at r ~ 25 R *, and steadily decreases outward. SO2 appears to be a "parent" molecule, formed near the stellar photosphere. In the asymmetric outflows, both SO and SO2 are more prominent at large stellar radii in dense (106-107 cm-3), clumpy material, achieving their maximum abundance between 200 and 600 R * with f ~ 3.0 × 10-8-1.5 × 10-7. These results suggest that in the collimated outflows, both species are either produced by shock chemistry or are remnant inner shell material swept up in the high-velocity winds.

  1. Utilizing the building envelope for power generation and conservation

    International Nuclear Information System (INIS)

    Lee, M.C.; Kuo, C.H.; Wang, F.J.

    2016-01-01

    Heat loading of the building envelope is caused by strong solar radiation and incorrect material selection. As a result of the heat loading of the building envelope, the indoor air temperature is increased, resulting in high energy consumption by air conditioners to maintain a comfortable indoor thermal environment. This study explores the use of a hybrid wall integrated with heat collectors (water piping system) and solar thermal power generators, which absorbs solar radiation through water to reduce heat transmission thereby saving energy and generating power. Power generation is achieved by an OD (oscillator device) that installed between a water tank (hot side) and building interior (cold side). The device acts by temperature differences between hot air (expansion) and cold air (contraction). CFD (computational dynamic simulation) was used to assess the effects of the hybrid wall on the interior environment. The results show that exterior heat is absorbed by cool water thereby reducing the heat transmission into the building, resulting in less energy consumption by air conditioners and power generation by use of temperature differences. - Highlights: • This study explores a hybrid building wall to save energy and generate power. • Power generators operated by air pressure change via hot tank and cool interior. • Less energy consumption by air conditioners and heating water. • Performance of CFD simulated results and experiment results are similar. • The energy saving efficiency is around 15 kWh/day via hybrid wall in west façade.

  2. Residential building envelope heat gain and cooling energy requirements

    International Nuclear Information System (INIS)

    Lam, Joseph C.; Tsang, C.L.; Li, Danny H.W.; Cheung, S.O.

    2005-01-01

    We present the energy use situation in Hong Kong from 1979 to 2001. The primary energy requirement (PER) nearly tripled during the 23-year period, rising from 195,405 TJ to 572,684 TJ. Most of the PER was used for electricity generation, and the electricity use in residential buildings rose from 7556 TJ (2099 GWh) to 32,799 TJ (9111 GWh), an increase of 334%. Air-conditioning accounted for about 40% of the total residential sector electricity consumption. A total of 144 buildings completed in the month of June during 1992-2001 were surveyed. Energy performance of the building envelopes was investigated in terms of the overall thermal transfer value (OTTV). To develop the appropriated parameters used in OTTV calculation, long-term measured weather data such as ambient temperature (1960-2001), horizontal global solar radiation (1992-2001) and global solar radiation on vertical surfaces (1996-2001) were examined. The OTTV found varied from 27 to 44 W/m 2 with a mean value of 37.7 W/m 2 . Building energy simulation technique using DOE-2.1E was employed to determine the cooling requirements and hence electricity use for building envelope designs with different OTTVs. It was found that cooling loads and electricity use could be expressed in terms of a simple two-parameter linear regression equation involving OTTV

  3. Do all Planetary Nebulae result from Common Envelopes?

    Science.gov (United States)

    De Marco, O.; Moe, M.; Herwig, F.; Politano, M.

    2005-12-01

    The common envelope interaction is responsible for evolved close binaries. Some of these binaries reside in the middle of planetary nebulae (PN). Conventional wisdom has it that only about 10% of all PN contain close binary central stars. Recent observational results, however, strongly suggest that most or even all PN are in close binary systems. Interestingly, our population synthesis calculations predict that the number of post-common envelope PN is in agreement with the total number of PN in the Galaxy. On the other hand, if all stars (single and in binaries) with mass between ˜1-8 M⊙ eject a PN, there would be 10-20 times many more PN in the galaxy than observed. This theoretical result is in agreement with the observations in suggesting that binary interactions play a functional rather than marginal role in the creation of PN. FH acknowledges funds from the U.S. Dept. of Energy, under contract W-7405-ENG-36 to Los Alamos National Laboratory. MP gratefully acknowledges NSF grant AST-0328484 to Marquette University.

  4. Crystal structure of the Japanese encephalitis virus envelope protein.

    Science.gov (United States)

    Luca, Vincent C; AbiMansour, Jad; Nelson, Christopher A; Fremont, Daved H

    2012-02-01

    Japanese encephalitis virus (JEV) is the leading global cause of viral encephalitis. The JEV envelope protein (E) facilitates cellular attachment and membrane fusion and is the primary target of neutralizing antibodies. We have determined the 2.1-Å resolution crystal structure of the JEV E ectodomain refolded from bacterial inclusion bodies. The E protein possesses the three domains characteristic of flavivirus envelopes and epitope mapping of neutralizing antibodies onto the structure reveals determinants that correspond to the domain I lateral ridge, fusion loop, domain III lateral ridge, and domain I-II hinge. While monomeric in solution, JEV E assembles as an antiparallel dimer in the crystal lattice organized in a highly similar fashion as seen in cryo-electron microscopy models of mature flavivirus virions. The dimer interface, however, is remarkably small and lacks many of the domain II contacts observed in other flavivirus E homodimers. In addition, uniquely conserved histidines within the JEV serocomplex suggest that pH-mediated structural transitions may be aided by lateral interactions outside the dimer interface in the icosahedral virion. Our results suggest that variation in dimer structure and stability may significantly influence the assembly, receptor interaction, and uncoating of virions.

  5. Functional Analysis of Glycosylation of Zika Virus Envelope Protein

    Directory of Open Access Journals (Sweden)

    Camila R. Fontes-Garfias

    2017-10-01

    Full Text Available Summary: Zika virus (ZIKV infection causes devastating congenital abnormities and Guillain-Barré syndrome. The ZIKV envelope (E protein is responsible for viral entry and represents a major determinant for viral pathogenesis. Like other flaviviruses, the ZIKV E protein is glycosylated at amino acid N154. To study the function of E glycosylation, we generated a recombinant N154Q ZIKV that lacks the E glycosylation and analyzed the mutant virus in mammalian and mosquito hosts. In mouse models, the mutant was attenuated, as evidenced by lower viremia, decreased weight loss, and no mortality; however, knockout of E glycosylation did not significantly affect neurovirulence. Mice immunized with the mutant virus developed a robust neutralizing antibody response and were completely protected from wild-type ZIKV challenge. In mosquitoes, the mutant virus exhibited diminished oral infectivity for the Aedes aegypti vector. Collectively, the results demonstrate that E glycosylation is critical for ZIKV infection of mammalian and mosquito hosts. : Zika virus (ZIKV causes devastating congenital abnormities and Guillain-Barré syndrome. Fontes-Garfias et al. showed that the glycosylation of ZIKV envelope protein plays an important role in infecting mosquito vectors and pathogenesis in mouse. Keywords: Zika virus, glycosylation, flavivirus entry, mosquito transmission, vaccine

  6. Focal Targeting of the Bacterial Envelope by Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Rafi eRashid

    2016-06-01

    Full Text Available Antimicrobial peptides (AMPs are utilized by both eukaryotic and prokaryotic organisms. AMPs such as the human beta defensins, human neutrophil peptides, human cathelicidin, and many bacterial bacteriocins are cationic and capable of binding to anionic regions of the bacterial surface. Cationic AMPs (CAMPs target anionic lipids (e.g. phosphatidylglycerol (PG and cardiolipins (CL in the cell membrane and anionic components (e.g. lipopolysaccharide (LPS and lipoteichoic acid (LTA of the cell envelope. Bacteria have evolved mechanisms to modify these same targets in order to resist CAMP killing, e.g. lysinylation of PG to yield cationic lysyl-PG and alanylation of LTA. Since CAMPs offer a promising therapeutic alternative to conventional antibiotics, which are becoming less effective due to rapidly emerging antibiotic resistance, there is a strong need to improve our understanding about the AMP mechanism of action. Recent literature suggests that AMPs often interact with the bacterial cell envelope at discrete foci. Here we review recent AMP literature, with an emphasis on focal interactions with bacteria, including (1 CAMP disruption mechanisms, (2 delocalization of membrane proteins and lipids by CAMPs, and (3 CAMP sensing systems and resistance mechanisms. We conclude with new approaches for studying the bacterial membrane, e.g., lipidomics, high resolution imaging and non-detergent-based membrane domain extraction.

  7. Binaural hearing in children using Gaussian enveloped and transposed tones.

    Science.gov (United States)

    Ehlers, Erica; Kan, Alan; Winn, Matthew B; Stoelb, Corey; Litovsky, Ruth Y

    2016-04-01

    Children who use bilateral cochlear implants (BiCIs) show significantly poorer sound localization skills than their normal hearing (NH) peers. This difference has been attributed, in part, to the fact that cochlear implants (CIs) do not faithfully transmit interaural time differences (ITDs) and interaural level differences (ILDs), which are known to be important cues for sound localization. Interestingly, little is known about binaural sensitivity in NH children, in particular, with stimuli that constrain acoustic cues in a manner representative of CI processing. In order to better understand and evaluate binaural hearing in children with BiCIs, the authors first undertook a study on binaural sensitivity in NH children ages 8-10, and in adults. Experiments evaluated sound discrimination and lateralization using ITD and ILD cues, for stimuli with robust envelope cues, but poor representation of temporal fine structure. Stimuli were spondaic words, Gaussian-enveloped tone pulse trains (100 pulse-per-second), and transposed tones. Results showed that discrimination thresholds in children were adult-like (15-389 μs for ITDs and 0.5-6.0 dB for ILDs). However, lateralization based on the same binaural cues showed higher variability than seen in adults. Results are discussed in the context of factors that may be responsible for poor representation of binaural cues in bilaterally implanted children.

  8. Hospitals Productivity Measurement Using Data Envelopment Analysis Technique.

    Science.gov (United States)

    Torabipour, Amin; Najarzadeh, Maryam; Arab, Mohammad; Farzianpour, Freshteh; Ghasemzadeh, Roya

    2014-11-01

    This study aimed to measure the hospital productivity using data envelopment analysis (DEA) technique and Malmquist indices. This is a cross sectional study in which the panel data were used in a 4 year period from 2007 to 2010. The research was implemented in 12 teaching and non-teaching hospitals of Ahvaz County. Data envelopment analysis technique and the Malmquist indices with an input-orientation approach, was used to analyze the data and estimation of productivity. Data were analyzed using the SPSS.18 and DEAP.2 software. Six hospitals (50%) had a value lower than 1, which represents an increase in total productivity and other hospitals were non-productive. the average of total productivity factor (TPF) was 1.024 for all hospitals, which represents a decrease in efficiency by 2.4% from 2007 to 2010. The average technical, technologic, scale and managerial efficiency change was 0.989, 1.008, 1.028, and 0.996 respectively. There was not a significant difference in mean productivity changes among teaching and non-teaching hospitals (P>0.05) (except in 2009 years). Productivity rate of hospitals had an increasing trend generally. However, the total average of productivity was decreased in hospitals. Besides, between the several components of total productivity, variation of technological efficiency had the highest impact on reduce of total average of productivity.

  9. A novel family of plant nuclear envelope-associated proteins.

    Science.gov (United States)

    Pawar, Vidya; Poulet, Axel; Détourné, Gwénaëlle; Tatout, Christophe; Vanrobays, Emmanuel; Evans, David E; Graumann, Katja

    2016-10-01

    This paper describes the characterisation of a new family of higher plant nuclear envelope-associated proteins (NEAPs) that interact with other proteins of the nuclear envelope. In the model plant Arabidopsis thaliana, the family consists of three genes expressed ubiquitously (AtNEAP1-3) and a pseudogene (AtNEAP4). NEAPs consist of extensive coiled-coil domains, followed by a nuclear localisation signal and a C-terminal predicted transmembrane domain. Domain deletion mutants confirm the presence of a functional nuclear localisation signal and transmembrane domain. AtNEAP proteins localise to the nuclear periphery as part of stable protein complexes, are able to form homo- and heteromers, and interact with the SUN domain proteins AtSUN1 and AtSUN2, involved in the linker of nucleoskeleton and cytoskeleton (LINC) complex. An A. thaliana cDNA library screen identified a putative transcription factor called AtbZIP18 as a novel interactor of AtNEAP1, which suggest a connection between NEAP and chromatin. An Atneap1 Atneap3 double-knockout mutant showed reduced root growth, and altered nuclear morphology and chromatin structure. Thus AtNEAPs are suggested as inner nuclear membrane-anchored coiled-coil proteins with roles in maintaining nuclear morphology and chromatin structure. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  10. Stress envelope of silicon carbide composites at elevated temperatures

    International Nuclear Information System (INIS)

    Nozawa, Takashi; Kim, Sunghun; Ozawa, Kazumi; Tanigawa, Hiroyasu

    2014-01-01

    To identify a comprehensive stress envelope, i.e., strength anisotropy map, of silicon carbide fiber-reinforced silicon carbide matrix composite (SiC/SiC composite) for practical component design, tensile and compressive tests were conducted using the small specimen test technique specifically tailored for high-temperature use. In-plane shear properties were, however, estimated using the off-axial tensile method and assuming that the mixed mode failure criterion, i.e., Tsai–Wu criterion, is valid for the composites. The preliminary test results indicate no significant degradation to either proportional limit stress (PLS) or fracture strength by tensile loading at temperatures below 1000 °C. A similarly good tolerance of compressive properties was identified at elevated temperatures, except for a slight degradation in PLS. With the high-temperature test data of tensile, compressive and in-plane shear properties, the stress envelopes at elevated temperatures were finally obtained. A slight reduction in the design limit was obvious at elevated temperatures when the compressive mode is dominant, whereas a negligibly small impact on the design is expected by considering the tensile loading case

  11. Stress envelope of silicon carbide composites at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Nozawa, Takashi, E-mail: nozawa.takashi67@jaea.go.jp [Japan Atomic Energy Agency, 2-166 Omotedate, Obuchi, Rokkasho, Aomori 039-3212 (Japan); Kim, Sunghun [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Ozawa, Kazumi; Tanigawa, Hiroyasu [Japan Atomic Energy Agency, 2-166 Omotedate, Obuchi, Rokkasho, Aomori 039-3212 (Japan)

    2014-10-15

    To identify a comprehensive stress envelope, i.e., strength anisotropy map, of silicon carbide fiber-reinforced silicon carbide matrix composite (SiC/SiC composite) for practical component design, tensile and compressive tests were conducted using the small specimen test technique specifically tailored for high-temperature use. In-plane shear properties were, however, estimated using the off-axial tensile method and assuming that the mixed mode failure criterion, i.e., Tsai–Wu criterion, is valid for the composites. The preliminary test results indicate no significant degradation to either proportional limit stress (PLS) or fracture strength by tensile loading at temperatures below 1000 °C. A similarly good tolerance of compressive properties was identified at elevated temperatures, except for a slight degradation in PLS. With the high-temperature test data of tensile, compressive and in-plane shear properties, the stress envelopes at elevated temperatures were finally obtained. A slight reduction in the design limit was obvious at elevated temperatures when the compressive mode is dominant, whereas a negligibly small impact on the design is expected by considering the tensile loading case.

  12. The Experimental Research on Seismic Capacity of the Envelope Systems with Steel Frame

    Science.gov (United States)

    Li, Jiuyang; Wang, Bingbing; Li, Hengxu

    2017-09-01

    In this paper, according to the present application situation of the external envelope systems steel frame in the severe cold region, the stuffed composite wall panels are improved, the flexible connection with the steel frame is designed, the reduced scale specimens are made, the seismic capacity test is made and some indexes of the envelope systems such as bearing capacity, energy consumption and ductility, etc. are compared, which provide reference for the development and application of the steel frame envelope systems.

  13. CCR5 Signal Transduction in Macrophages by Human Immunodeficiency Virus and Simian Immunodeficiency Virus Envelopes

    OpenAIRE

    Arthos, James; Rubbert, Andrea; Rabin, Ronald L.; Cicala, Claudia; Machado, Elizabeth; Wildt, Kathryne; Hanbach, Meredith; Steenbeke, Tavis D.; Swofford, Ruth; Farber, Joshua M.; Fauci, Anthony S.

    2000-01-01

    The capacity of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) envelopes to transduce signals through chemokine coreceptors on macrophages was examined by measuring the ability of recombinant envelope proteins to mobilize intracellular calcium stores. Both HIV and SIV envelopes mobilized calcium via interactions with CCR5. The kinetics of these responses were similar to those observed when macrophages were treated with MIP-1β. Distinct differences in the capacity o...

  14. Combined centroid-envelope dynamics of intense, magnetically focused charged beams surrounded by conducting walls

    International Nuclear Information System (INIS)

    Fiuza, K.; Rizzato, F.B.; Pakter, R.

    2006-01-01

    In this paper we analyze the combined envelope-centroid dynamics of magnetically focused high-intensity charged beams surrounded by conducting walls. Similar to the case where conducting walls are absent, it is shown that the envelope and centroid dynamics decouple from each other. Mismatched envelopes still decay into equilibrium with simultaneous emittance growth, but the centroid keeps oscillating with no appreciable energy loss. Some estimates are performed to analytically obtain characteristics of halo formation seen in the full simulations

  15. Ultra-compact high velocity clouds in the ALFALFA HI survey: Candidate Local Group galaxies?

    Science.gov (United States)

    Adams, Elizabeth Ann Kovenz

    The increased sensitivity and spatial resolution of the ALFALFA HI survey has resulted in the detection of ultra-compact high velocity clouds (UCHVCs). These objects are good candidates to represent low mass gas-rich galaxies in the Local Group and Local Volume with stellar populations that are too faint to be detected in extant optical surveys. This idea is referred to as the "minihalo hypothesis". We identify the UCHVCs within the ALFALFA dataset via the use of a 3D matched filtering signal identification algorithm. UCHVCs are selected based on a compact size ( 120 km s-1) and isolation. Within the 40% complete ALFALFA survey (alpha.40), 59 UCHVCs are identified; 19 are in a most-isolated subset and are the best galaxy candidates. Due to the presence of large HVC complexes in the fall sky, most notably the Magellanic Stream, the association of UCHVCs with existing structure cannot be ruled out. In the spring sky, the spatial and kinematic distribution of the UCHVCs is consistent with simulations of dark matter halos within the Local Group. In addition, the HI properties of the UCHVCs (if placed at 1 Mpc) are consistent with both theoretical and observational predictions for low mass gas-rich galaxies. Importantly, the HI properties of the UCHVCs are consistent with those of two recently discovered low mass gas-rich galaxies in the Local Group and Local Volume, Leo T and Leo P. Detailed follow-up observations are key for addressing the minihalo hypothesis. High resolution HI observations can constrain the environment of a UCHVC and offer evidence for a hosting dark matter halo through evidence of rotation support and comparison to theoretical models. Observations of one UCHVC at high resolution (15'') reveal the presence of a clumpy HI distribution, similar to both low mass galaxies and circumgalactic compact HVCs. An extended envelope containing ˜50% of the HI flux is resolved out by the array configuration; observations at lower spatial resolution can recover

  16. Acoustic and streaming velocity components in a resonant waveguide at high acoustic levels.

    Science.gov (United States)

    Daru, Virginie; Reyt, Ida; Bailliet, Hélène; Weisman, Catherine; Baltean-Carlès, Diana

    2017-01-01

    Rayleigh streaming is a steady flow generated by the interaction between an acoustic wave and a solid wall, generally assumed to be second order in a Mach number expansion. Acoustic streaming is well known in the case of a stationary plane wave at low amplitude: it has a half-wavelength spatial periodicity and the maximum axial streaming velocity is a quadratic function of the acoustic velocity amplitude at antinode. For higher acoustic levels, additional streaming cells have been observed. Results of laser Doppler velocimetry measurements are here compared to direct numerical simulations. The evolution of axial and radial velocity components for both acoustic and streaming velocities is studied from low to high acoustic amplitudes. Two streaming flow regimes are pointed out, the axial streaming dependency on acoustics going from quadratic to linear. The evolution of streaming flow is different for outer cells and for inner cells. Also, the hypothesis of radial streaming velocity being of second order in a Mach number expansion, is not valid at high amplitudes. The change of regime occurs when the radial streaming velocity amplitude becomes larger than the radial acoustic velocity amplitude, high levels being therefore characterized by nonlinear interaction of the different velocity components.

  17. The Carnegie Supernova Project I. Analysis of stripped-envelope supernova light curves

    Science.gov (United States)

    Taddia, F.; Stritzinger, M. D.; Bersten, M.; Baron, E.; Burns, C.; Contreras, C.; Holmbo, S.; Hsiao, E. Y.; Morrell, N.; Phillips, M. M.; Sollerman, J.; Suntzeff, N. B.

    2018-02-01

    Stripped-envelope (SE) supernovae (SNe) include H-poor (Type IIb), H-free (Type Ib), and He-free (Type Ic) events thought to be associated with the deaths of massive stars. The exact nature of their progenitors is a matter of debate with several lines of evidence pointing towards intermediate mass (MinitCarnegie Supernova Project (CSP-I) that are unparalleled in terms of photometric accuracy and wavelength range. Light-curve parameters are estimated through the fits of an analytical function and trends are searched for among the resulting fit parameters. Detailed inspection of the dataset suggests a tentative correlation between the peak absolute B-band magnitude and Δm15(B), while the post maximum light curves reveals a correlation between the late-time linear slope and Δm15. Making use of the full set of optical and near-IR photometry, combined with robust host-galaxy extinction corrections, comprehensive bolometric light curves are constructed and compared to both analytic and hydrodynamical models. This analysis finds consistent results among the two different modeling techniques and from the hydrodynamical models we obtained ejecta masses of 1.1-6.2M⊙, 56Ni masses of 0.03-0.35M⊙, and explosion energies (excluding two SNe Ic-BL) of 0.25-3.0 × 1051 erg. Our analysis indicates that adopting κ = 0.07 cm2 g-1 as the mean opacity serves to be a suitable assumption when comparing Arnett-model results to those obtained from hydrodynamical calculations. We also find that adopting He I and O I line velocities to infer the expansion velocity in He-rich and He-poor SNe, respectively, provides ejecta masses relatively similar to those obtained by using the Fe II line velocities, although the use of Fe II as a diagnostic does imply higher explosion energies. The inferred range of ejecta masses are compatible with intermediate mass (MZAMS ≤ 20M⊙) progenitor stars in binary systems for the majority of SE SNe. Furthermore, our hydrodynamical modeling of the

  18. Evolution of the spherical clusters

    International Nuclear Information System (INIS)

    Surdin, V.G.

    1978-01-01

    The possible processes of the Galaxy spherical clusters formation and evolution are described on a popular level. The orbits of spherical cluster motion and their spatial velocities are determined. Given are the distrbutions of spherical cluster stars according to their velocities and the observed distribution of spherical clusters in the area of the Galaxy slow evolution. The dissipation and dynamic friction processes destructing clusters with the mass less than 10 4 of solar mass and bringing about the reduction of clusters in the Galaxy are considered. The paradox of forming mainly X-ray sources in spherical clusters is explained. The schematic image of possible ways of forming X-ray sources in spherical clusters is given

  19. Hyperaccretion during Tidal Disruption Events: Weakly Bound Debris Envelopes and Jets

    Science.gov (United States)

    Coughlin, Eric R.; Begelman, Mitchell C.

    2014-02-01

    After the destruction of the star during a tidal disruption event (TDE), the cataclysmic encounter between a star and the supermassive black hole (SMBH) of a galaxy, approximately half of the original stellar debris falls back onto the hole at a rate that can initially exceed the Eddington limit by orders of magnitude. We argue that the angular momentum of this matter is too low to allow it to attain a disk-like configuration with accretion proceeding at a mildly super-Eddington rate, the excess energy being carried away by a combination of radiative losses and radially distributed winds. Instead, we propose that the infalling gas traps accretion energy until it inflates into a weakly bound, quasi-spherical structure with gas extending nearly to the poles. We study the structure and evolution of such "zero-Bernoulli accretion" flows as a model for the super-Eddington phase of TDEs. We argue that such flows cannot stop extremely super-Eddington accretion from occurring, and that once the envelope is maximally inflated, any excess accretion energy escapes through the poles in the form of powerful jets. We compare the predictions of our model to Swift J1644+57, the putative super-Eddington TDE, and show that it can qualitatively reproduce some of its observed features. Similar models, including self-gravity, could be applicable to gamma-ray bursts from collapsars and the growth of SMBH seeds inside quasi-stars.

  20. Hyperaccretion during tidal disruption events: Weakly bound debris envelopes and jets

    Energy Technology Data Exchange (ETDEWEB)

    Coughlin, Eric R.; Begelman, Mitchell C., E-mail: eric.coughlin@colorado.edu, E-mail: mitch@jila.colorado.edu [Also at Department of Astrophysical and Planetary Sciences, University of Colorado, UCB 391, Boulder, CO 80309, USA. (United States)

    2014-02-01

    After the destruction of the star during a tidal disruption event (TDE), the cataclysmic encounter between a star and the supermassive black hole (SMBH) of a galaxy, approximately half of the original stellar debris falls back onto the hole at a rate that can initially exceed the Eddington limit by orders of magnitude. We argue that the angular momentum of this matter is too low to allow it to attain a disk-like configuration with accretion proceeding at a mildly super-Eddington rate, the excess energy being carried away by a combination of radiative losses and radially distributed winds. Instead, we propose that the infalling gas traps accretion energy until it inflates into a weakly bound, quasi-spherical structure with gas extending nearly to the poles. We study the structure and evolution of such 'zero-Bernoulli accretion' flows as a model for the super-Eddington phase of TDEs. We argue that such flows cannot stop extremely super-Eddington accretion from occurring, and that once the envelope is maximally inflated, any excess accretion energy escapes through the poles in the form of powerful jets. We compare the predictions of our model to Swift J1644+57, the putative super-Eddington TDE, and show that it can qualitatively reproduce some of its observed features. Similar models, including self-gravity, could be applicable to gamma-ray bursts from collapsars and the growth of SMBH seeds inside quasi-stars.

  1. Hyperaccretion during tidal disruption events: Weakly bound debris envelopes and jets

    International Nuclear Information System (INIS)

    Coughlin, Eric R.; Begelman, Mitchell C.

    2014-01-01

    After the destruction of the star during a tidal disruption event (TDE), the cataclysmic encounter between a star and the supermassive black hole (SMBH) of a galaxy, approximately half of the original stellar debris falls back onto the hole at a rate that can initially exceed the Eddington limit by orders of magnitude. We argue that the angular momentum of this matter is too low to allow it to attain a disk-like configuration with accretion proceeding at a mildly super-Eddington rate, the excess energy being carried away by a combination of radiative losses and radially distributed winds. Instead, we propose that the infalling gas traps accretion energy until it inflates into a weakly bound, quasi-spherical structure with gas extending nearly to the poles. We study the structure and evolution of such 'zero-Bernoulli accretion' flows as a model for the super-Eddington phase of TDEs. We argue that such flows cannot stop extremely super-Eddington accretion from occurring, and that once the envelope is maximally inflated, any excess accretion energy escapes through the poles in the form of powerful jets. We compare the predictions of our model to Swift J1644+57, the putative super-Eddington TDE, and show that it can qualitatively reproduce some of its observed features. Similar models, including self-gravity, could be applicable to gamma-ray bursts from collapsars and the growth of SMBH seeds inside quasi-stars.

  2. African Swine Fever Virus Undergoes Outer Envelope Disruption, Capsid Disassembly and Inner Envelope Fusion before Core Release from Multivesicular Endosomes.

    Directory of Open Access Journals (Sweden)

    Bruno Hernáez

    2016-04-01

    Full Text Available African swine fever virus (ASFV is a nucleocytoplasmic large DNA virus (NCLDV that causes a highly lethal disease in domestic pigs. As other NCLDVs, the extracellular form of ASFV possesses a multilayered structure consisting of a genome-containing nucleoid successively wrapped by a thick protein core shell, an inner lipid membrane, an icosahedral protein capsid and an outer lipid envelope. This structural complexity suggests an intricate mechanism of internalization in order to deliver the virus genome into the cytoplasm. By using flow cytometry in combination with pharmacological entry inhibitors, as well as fluorescence and electron microscopy approaches, we have dissected the entry and uncoating pathway used by ASFV to infect the macrophage, its natural host cell. We found that purified extracellular ASFV is internalized by both constitutive macropinocytosis and clathrin-mediated endocytosis. Once inside the cell, ASFV particles move from early endosomes or macropinosomes to late, multivesicular endosomes where they become uncoated. Virus uncoating requires acidic pH and involves the disruption of the outer membrane as well as of the protein capsid. As a consequence, the inner viral membrane becomes exposed and fuses with the limiting endosomal membrane to release the viral core into the cytosol. Interestingly, virus fusion is dependent on virus protein pE248R, a transmembrane polypeptide of the inner envelope that shares sequence similarity with some members of the poxviral entry/fusion complex. Collective evidence supports an entry model for ASFV that might also explain the uncoating of other multienveloped icosahedral NCLDVs.

  3. Stellar evolution

    CERN Document Server

    Meadows, A J

    2013-01-01

    Stellar Evolution, Second Edition covers the significant advances in the understanding of birth, life, and death of stars.This book is divided into nine chapters and begins with a description of the characteristics of stars according to their brightness, distance, size, mass, age, and chemical composition. The next chapters deal with the families, structure, and birth of stars. These topics are followed by discussions of the chemical composition and the evolution of main-sequence stars. A chapter focuses on the unique features of the sun as a star, including its evolution, magnetic fields, act

  4. INTERACTION OF CLOSE-IN PLANETS WITH THE MAGNETOSPHERE OF THEIR HOST STARS. II. SUPER-EARTHS AS UNIPOLAR INDUCTORS AND THEIR ORBITAL EVOLUTION

    International Nuclear Information System (INIS)

    Laine, Randy O.; Lin, Douglas N. C.

    2012-01-01

    Planets with several Earth masses and orbital periods of a few days have been discovered through radial velocity and transit surveys. Regardless of their formation mechanism, an important evolution issue is the efficiency of their retention in the proximity of their host stars. If these 'super-Earths' attained their present-day orbits during or shortly after the T Tauri phase of their host stars, a large fraction of these planets would have encountered an intense stellar magnetic field. These rocky planets have a higher conductivity than the atmosphere of their host stars and, therefore, the magnetic flux tube connecting them would slip though the envelope of the host stars faster than across the planets. The induced electromotive force across the planet's diameter leads to a potential drop which propagates along a flux tube away from the planet with an Alfvén speed. The foot of the flux tube would sweep across the stellar surface and the potential drop across the field lines drives a DC current analogous to that proposed for the electrodynamics of the Io-Jupiter system. The ohmic dissipation of this current produces potentially observable hot spots in the star envelope. It also heats the planet and leads to a torque which drives the planet's orbit to evolve toward both circularization and a state of synchronization with the spin of the star. The net effect is the damping of the planet's orbital eccentricity. Around slowly (or rapidly) spinning stars, this process also causes rocky planets with periods less than a few days to undergo orbital decay (or expansion/stagnation) within a few Myr. In principle, this effect can determine the retention efficiency of short-period hot Earths. We also estimate the ohmic dissipation interior to these planets and show that it can lead to severe structure evolution and potential loss of volatile material in them. However, these effects may be significantly weakened by the reconnection of the induced field.

  5. Radial Velocities of 41 Kepler Eclipsing Binaries

    Science.gov (United States)

    Matson, Rachel A.; Gies, Douglas R.; Guo, Zhao; Williams, Stephen J.

    2017-12-01

    Eclipsing binaries are vital for directly determining stellar parameters without reliance on models or scaling relations. Spectroscopically derived parameters of detached and semi-detached binaries allow us to determine component masses that can inform theories of stellar and binary evolution. Here we present moderate resolution ground-based spectra of stars in close binary systems with and without (detected) tertiary companions observed by NASA’s Kepler mission and analyzed for eclipse timing variations. We obtain radial velocities and spectroscopic orbits for five single-lined and 35 double-lined systems, and confirm one false positive eclipsing binary. For the double-lined spectroscopic binaries, we also determine individual component masses and examine the mass ratio {M}2/{M}1 distribution, which is dominated by binaries with like-mass pairs and semi-detached classical Algol systems that have undergone mass transfer. Finally, we constrain the mass of the tertiary component for five double-lined binaries with previously detected companions.

  6. Mutations That Alter the Bacterial Cell Envelope Increase Lipid Production

    Energy Technology Data Exchange (ETDEWEB)

    Lemmer, Kimberly C.; Zhang, Weiping; Langer, Samantha J.; Dohnalkova, Alice; Hu, Dehong; Lemke, Rachelle A.; Piotrowski, Jeff S.; Orr, Galya; Noguera, Daniel R.; Donohue, Timothy J.

    2017-05-23

    ABSTRACT

    Lipids from microbes offer a promising source of renewable alternatives to petroleum-derived compounds. In particular, oleaginous microbes are of interest because they accumulate a large fraction of their biomass as lipids. In this study, we analyzed genetic changes that alter lipid accumulation inRhodobacter sphaeroides. By screening anR. sphaeroidesTn5mutant library for insertions that increased fatty acid content, we identified 10 high-lipid (HL) mutants for further characterization. These HL mutants exhibited increased sensitivity to drugs that target the bacterial cell envelope and changes in shape, and some had the ability to secrete lipids, with two HL mutants accumulating ~60% of their total lipids extracellularly. When one of the highest-lipid-secreting strains was grown in a fed-batch bioreactor, its lipid content was comparable to that of oleaginous microbes, with the majority of the lipids secreted into the medium. Based on the properties of these HL mutants, we conclude that alterations of the cell envelope are a previously unreported approach to increase microbial lipid production. We also propose that this approach may be combined with knowledge about biosynthetic pathways, in this or other microbes, to increase production of lipids and other chemicals.

    IMPORTANCEThis paper reports on experiments to understand how to increase microbial lipid production. Microbial lipids are often cited as one renewable replacement for petroleum-based fuels and chemicals, but strategies to increase the yield of these compounds are needed to achieve this goal. While lipid biosynthesis is often well understood, increasing yields of these compounds to industrially relevant levels is a challenge, especially since genetic, synthetic biology, or engineering approaches are not feasible in many microbes. We show that altering the bacterial cell envelope can be used to increase

  7. CISBAT 2007 - Design and renovation of building envelopes (bioclimatic architecture)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    This is the second part of the proceedings of the 2007 CISBAT conference on Renewables in a changing climate, held in Lausanne, Switzerland. On the subject of sustainable building envelopes the following oral contributions are summarised: 'Flexible photovoltaics integrated in transparent membrane and pneumatic foil constructions', 'Development of a numerical thermal model for double skin facades', 'Thermal performance analysis for an electrochromic vacuum glazing with low emittance coatings', 'Challenging the public building sector: optimization of energy performance by sustainable strategies', 'Simulation of the thermal performance of a climate adaptive skin', 'Possibilities for upgrading prefabricated concrete building envelopes', 'Experimental study of airflow and heat transfer in a double skin facade with blinds', 'Energy efficiency of a glazing system - Case study: a dynamic glazing and double skin facades - the use of venetian blinds and night ventilation for saving energy on mediterranean climate'. Poster-sessions on the subject include 'Adaptive building envelopes design ', 'GRC facade panels in Brazil', 'Solar absorptance of building opaque surfaces', 'Evaluating the thermal behavior of exterior walls (in residential buildings of hot-dry climate of Yazd)', 'Energy performance of buildings and local energy policy: the case of new residential buildings in Greve in Chianti (Firenze)', 'Space heating and domestic hot water energy demand in high-level-insulation multi-storey buildings in Tuscany (Italy)', 'Is 2000 W society possible, affordable, and socially acceptable for the Vaud existing school building?', 'Development of simplified method for measuring solar shading performance of windows', 'Studies of ecological architecture in China's Loess Plateau region', 'Contemporary mud

  8. Velocity distribution of fragments of catastrophic impacts

    Science.gov (United States)

    Takagi, Yasuhiko; Kato, Manabu; Mizutani, Hitoshi

    1992-01-01

    Three dimensional velocities of fragments produced by laboratory impact experiments were measured for basalts and pyrophyllites. The velocity distribution of fragments obtained shows that the velocity range of the major fragments is rather narrow, at most within a factor of 3 and that no clear dependence of velocity on the fragment mass is observed. The NonDimensional Impact Stress (NDIS) defined by Mizutani et al. (1990) is found to be an appropriate scaling parameter to describe the overall fragment velocity as well as the antipodal velocity.

  9. Complex-envelope alternating-direction-implicit FDTD method for simulating active photonic devices with semiconductor/solid-state media.

    Science.gov (United States)

    Singh, Gurpreet; Ravi, Koustuban; Wang, Qian; Ho, Seng-Tiong

    2012-06-15

    A complex-envelope (CE) alternating-direction-implicit (ADI) finite-difference time-domain (FDTD) approach to treat light-matter interaction self-consistently with electromagnetic field evolution for efficient simulations of active photonic devices is presented for the first time (to our best knowledge). The active medium (AM) is modeled using an efficient multilevel system of carrier rate equations to yield the correct carrier distributions, suitable for modeling semiconductor/solid-state media accurately. To include the AM in the CE-ADI-FDTD method, a first-order differential system involving CE fields in the AM is first set up. The system matrix that includes AM parameters is then split into two time-dependent submatrices that are then used in an efficient ADI splitting formula. The proposed CE-ADI-FDTD approach with AM takes 22% of the time as the approach of the corresponding explicit FDTD, as validated by semiconductor microdisk laser simulations.

  10. Electron velocity and momentum density

    International Nuclear Information System (INIS)

    Perkins, G.A.

    1978-01-01

    A null 4-vector eta + sigma/sub μ/based on Dirac's relativistic electron equation, is shown explicitly for a plane wave and various Coulomb states. This 4-vector constitutes a mechanical ''model'' for the electron in those staes, and expresses the important spinor quantities represented conventionally by n, f, g, m, j, kappa, l, and s. The model for a plane wave agrees precisely with the relation between velocity and phase gradient customarily used in quantum theory, but the models for Coulomb states contradict that relation

  11. A two stage data envelopment analysis model with undesirable output

    Science.gov (United States)

    Shariff Adli Aminuddin, Adam; Izzati Jaini, Nur; Mat Kasim, Maznah; Nawawi, Mohd Kamal Mohd

    2017-09-01

    The dependent relationship among the decision making units (DMU) is usually assumed to be non-existent in the development of Data Envelopment Analysis (DEA) model. The dependency can be represented by the multi-stage DEA model, where the outputs from the precedent stage will be the inputs for the latter stage. The multi-stage DEA model evaluate both the efficiency score for each stages and the overall efficiency of the whole process. The existing multi stage DEA models do not focus on the integration with the undesirable output, in which the higher input will generate lower output unlike the normal desirable output. This research attempts to address the inclusion of such undesirable output and investigate the theoretical implication and potential application towards the development of multi-stage DEA model.

  12. Data Envelopment Analysis with Uncertain Inputs and Outputs

    Directory of Open Access Journals (Sweden)

    Meilin Wen

    2014-01-01

    Full Text Available Data envelopment analysis (DEA, as a useful management and decision tool, has been widely used since it was first invented by Charnes et al. in 1978. On the one hand, the DEA models need accurate inputs and outputs data. On the other hand, in many situations, inputs and outputs are volatile and complex so that they are difficult to measure in an accurate way. The conflict leads to the researches of uncertain DEA models. This paper will consider DEA in uncertain environment, thus producing a new model based on uncertain measure. Due to the complexity of the new uncertain DEA model, an equivalent deterministic model is presented. Finally, a numerical example is presented to illustrate the effectiveness of the uncertain DEA model.

  13. Modeling technical efficiency of inshore fishery using data envelopment analysis

    Science.gov (United States)

    Rahman, Rahayu; Zahid, Zalina; Khairi, Siti Shaliza Mohd; Hussin, Siti Aida Sheikh

    2016-10-01

    Fishery industry contributes significantly to the economy of Malaysia. This study utilized Data Envelopment Analysis application in estimating the technical efficiency of fishery in Terengganu, a state on the eastern coast of Peninsular Malaysia, based on multiple output, i.e. total fish landing and income of fishermen with six inputs, i.e. engine power, vessel size, number of trips, number of workers, cost and operation distance. The data were collected by survey conducted between November and December 2014. The decision making units (DMUs) involved 100 fishermen from 10 fishery areas. The result showed that the technical efficiency in Season I (dry season) and Season II (rainy season) were 90.2% and 66.7% respectively. About 27% of the fishermen were rated to be efficient during Season I, meanwhile only 13% of the fishermen achieved full efficiency 100% during Season II. The results also found out that there was a significance difference in the efficiency performance between the fishery areas.

  14. Modeling data irregularities and structural complexities in data envelopment analysis

    CERN Document Server

    Zhu, Joe

    2007-01-01

    In a relatively short period of time, Data Envelopment Analysis (DEA) has grown into a powerful quantitative, analytical tool for measuring and evaluating performance. It has been successfully applied to a whole variety of problems in many different contexts worldwide. This book deals with the micro aspects of handling and modeling data issues in modeling DEA problems. DEA's use has grown with its capability of dealing with complex "service industry" and the "public service domain" types of problems that require modeling of both qualitative and quantitative data. This handbook treatment deals with specific data problems including: imprecise or inaccurate data; missing data; qualitative data; outliers; undesirable outputs; quality data; statistical analysis; software and other data aspects of modeling complex DEA problems. In addition, the book will demonstrate how to visualize DEA results when the data is more than 3-dimensional, and how to identify efficiency units quickly and accurately.

  15. Estimating returns to scale in imprecise data envelopment analysis

    DEFF Research Database (Denmark)

    Hatami-Marbini, Adel; Beigi, Zahra Ghelej; Hougaard, Jens Leth

    The economic concept of Returns-to-Scale (RTS) has been intensively studied in the context of Data Envelopment Analysis (DEA). The conventional DEA models that are used for RTS classification require well-defined and accurate data whereas in reality data are often imprecise, vague, uncertain......-decreasing and variable RTS. The situation for non-increasing (non-decreasing) RTS is then divided into two partitions; constant or decreasing (constant or increasing) RTS using sensitivity analysis. Additionally, the situation for variable RTS is split into three partitions consisting of constant, decreasing...... and increasing RTS using sensitivity analysis. Finally, we present the stability region of an observation while preserving its current RTS classification using the optimal values of a set of proposed DEA-based models....

  16. A statistical test for outlier identification in data envelopment analysis

    Directory of Open Access Journals (Sweden)

    Morteza Khodabin

    2010-09-01

    Full Text Available In the use of peer group data to assess individual, typical or best practice performance, the effective detection of outliers is critical for achieving useful results. In these ‘‘deterministic’’ frontier models, statistical theory is now mostly available. This paper deals with the statistical pared sample method and its capability of detecting outliers in data envelopment analysis. In the presented method, each observation is deleted from the sample once and the resulting linear program is solved, leading to a distribution of efficiency estimates. Based on the achieved distribution, a pared test is designed to identify the potential outlier(s. We illustrate the method through a real data set. The method could be used in a first step, as an exploratory data analysis, before using any frontier estimation.

  17. Construction Project Success ranking through the Data Envelopment Analysis

    Directory of Open Access Journals (Sweden)

    Mazyar Zahedi-Seresht

    2014-09-01

    Full Text Available The purpose of this paper is to rank construction projects' success in a post delivery phase. To attain this objective, a data envelopment analysis (DEA approach is used. The model's output is a project success index which is calculated based on five project success criteria. These criteria which are determined by a two-round Delphi questionnaire survey are time performance, cost performance, quality, HSE, and customer satisfaction. The input factors which have effects on the output measures are Organizational Sponsorship, Project Manager Competency, Customer Organization, Project Operational Environment and Organizational Experience. The tool adopted to determine these factors is questionnaire. This model is applied for 9 projects with different importance of output and input factors and the reasonable result is achieved for ranking these projects.

  18. Frontier Assignment for Sensitivity Analysis of Data Envelopment Analysis

    Science.gov (United States)

    Naito, Akio; Aoki, Shingo; Tsuji, Hiroshi

    To extend the sensitivity analysis capability for DEA (Data Envelopment Analysis), this paper proposes frontier assignment based DEA (FA-DEA). The basic idea of FA-DEA is to allow a decision maker to decide frontier intentionally while the traditional DEA and Super-DEA decide frontier computationally. The features of FA-DEA are as follows: (1) provides chances to exclude extra-influential DMU (Decision Making Unit) and finds extra-ordinal DMU, and (2) includes the function of the traditional DEA and Super-DEA so that it is able to deal with sensitivity analysis more flexibly. Simple numerical study has shown the effectiveness of the proposed FA-DEA and the difference from the traditional DEA.

  19. Development of building envelope structures; Udvikling af klimaskaermskonstruktioner

    Energy Technology Data Exchange (ETDEWEB)

    Monefeldt Tommerup, H. [Danmarks Tekniske Univ., Lyngby (Denmark); Munch-Andersen, J. [Statens Byggeforskningsinstitut, Hoersholm (Denmark); Kjaer Esbensen, P. [Danmarks Tekniske Univ., Lyngby (Denmark)

    2000-08-01

    The present report concludes the work concerning the development of building envelope constructions, which can form the basis of new buildings with considerably less heat demand than in the present building regulations. It has been made probable that it is technically possible to build exterior walls with less heat loss than those just complying with the requirements of the current building regulations with no considerable added use of material apart from insulation. In their structure many of the shown constructions resemble types that are used today, while others presuppose that one part of the wall is attached to the other part or possibly to the rafters. Calculations concerning the importance of heat capacity for a 100 m{sup 2} single-family house have been made which confirm that by using heavy rather than light envelope constructions the reduction of the heating requirements is relatively small. Therefore optimisation of the insulation level can be carried out separately on the building components. A method has been developed for the evaluation of the optimum insulation level for the individual building components of the building envelope based on life cycle cost analysis. The method is based on making up the changes in the operational energy costs/ heating-costs and the cost of construction due to a change in the insulation thickness over a 30-year period. The life span of the primary parts of the building envelope is estimated at 100 years. It is assumed that the gross energy consumption that covers the heating requirements and the heat loss (determined by a simple calculation of degree days) changes concurrently with the change in the insulation thickness, which has been proved to be a reasonable approximation. The life cycle cost analysis has been carried out for a test-house of about 100 m{sup 2} and with two different energy price scenarios: 0.60 dkk/kWh (including taxes and VAT) which roughly corresponds to the present energy price level, and 1.20 dkk

  20. Hepatitis C Virus E2 Envelope Glycoprotein Core Structure

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Leopold; Giang, Erick; Nieusma, Travis; Kadam, Rameshwar U.; Cogburn, Kristin E.; Hua, Yuanzi; Dai, Xiaoping; Stanfield, Robyn L.; Burton, Dennis R.; Ward, Andrew B.; Wilson, Ian A.; Law, Mansun

    2014-08-26

    Hepatitis C virus (HCV), a Hepacivirus, is a major cause of viral hepatitis, liver cirrhosis, and hepatocellular carcinoma. HCV envelope glycoproteins E1 and E2 mediate fusion and entry into host cells and are the primary targets of the humoral immune response. The crystal structure of the E2 core bound to broadly neutralizing antibody AR3C at 2.65 angstroms reveals a compact architecture composed of a central immunoglobulin-fold β sandwich flanked by two additional protein layers. The CD81 receptor binding site was identified by electron microscopy and site-directed mutagenesis and overlaps with the AR3C epitope. The x-ray and electron microscopy E2 structures differ markedly from predictions of an extended, three-domain, class II fusion protein fold and therefore provide valuable information for HCV drug and vaccine design.

  1. Efficiency of Polish metallurgical industry based on data envelopment analysis

    Directory of Open Access Journals (Sweden)

    J. Baran

    2016-04-01

    Full Text Available The main purpose of this paper is to compare the technical efficiency of 12 sectors manufacturing basic metals and metal products in Poland. This article presents the use of Data Envelopment Analysis models, to determine overall technical efficiency, pure technical efficiency and scale efficiency of metallurgical branches in Poland. The average technical efficiency of metallurgical industry in Poland was quite high. The analysis gives a possibility to create a ranking of sectors. Three branches were found to be fully efficient: manufacture of basic iron and steel and of ferroalloys, manufacture of basic precious and other non - ferrous metals and manufacture of tubes, pipes, hollow profiles and related fittings, of steel. The results point out the reasons of the inefficiency and provide improving directions for the inefficient sectors.

  2. ASSESSMENT OF REGIONAL EFFICIENCY IN CROATIA USING DATA ENVELOPMENT ANALYSIS

    Directory of Open Access Journals (Sweden)

    Danijela Rabar

    2013-02-01

    Full Text Available In this paper, regional efficiency of Croatian counties is measured in three-year period (2005-2007 using Data Envelopment Analysis (DEA. The set of inputs and outputs consists of seven socioeconomic indicators. Analysis is carried out using models with assumption of variable returns-to-scale. DEA identifies efficient counties as benchmark members and inefficient counties that are analyzed in detail to determine the sources and the amounts of their inefficiency in each source. To enable proper monitoring of development dynamics, window analysis is applied. Based on the results, guidelines for implementing necessary improvements to achieve efficiency are given. Analysis reveals great disparities among counties. In order to alleviate naturally, historically and politically conditioned unequal county positions over which economic policy makers do not have total control, categorical approach is introduced as an extension to the basic DEA models. This approach, combined with window analysis, changes relations among efficiency scores in favor of continental counties.

  3. Determinants of foamy virus envelope glycoprotein mediated resistance to superinfection

    International Nuclear Information System (INIS)

    Berg, Angelika; Pietschmann, Thomas; Rethwilm, Axel; Lindemann, Dirk

    2003-01-01

    Little is known about the nature of foamy virus (FV) receptor molecules on target cells and their interaction with the viral glycoproteins. Similar to other viruses, cellular expression of the FV Env protein is sufficient to induce resistance to exogenous FV, a phenomenon called superinfection resistance (SIR). In this study we define determinants of the FV Env protein essential for mediating SIR. FV Env requires the extracellular domains of the SU and the TM subunits as well as membrane anchorage, efficient cell surface transport, and most probably correct subunit processing. This is in contrast to murine leukemia virus where secreted proteins comprising the receptor-binding domain in SU are sufficient to induce SIR. Furthermore, we demonstrate that cellular expression of the prototype FV envelope proteins induces SIR against pseudotypes with glycoproteins of other FV species, including of simian, feline, bovine, and equine origin. This implies that all of them use the same receptor molecules for viral entry

  4. Bank branch operating efficiency: evaluation with data envelopment analysis

    Directory of Open Access Journals (Sweden)

    Roozbeh Talebi Zarinkamar

    2014-10-01

    Full Text Available Measuring the relative efficiency of similar units has been a popular research especially when the units were mostly non-financial. Even, similar financial units may not be necessarily evaluated based on traditional financial figures such as return of equities, return of assets, etc. In this paper, we present an empirical investigation to measure the relative efficiency of 30 branches of an Iranian bank named Bank Mellat. The study considers four inputs including operating expenses, interest paid, capital expenditures and fixed assets. In addition, we use customers’ bank deposit, commissions and loans paid as output parameters. Using three different data envelopment analyses, the study measures the relative efficiencies of all units. The preliminary results indicate that most banks were working under desirable level of efficiency.

  5. Low-Cost Phase Change Material for Building Envelopes

    Energy Technology Data Exchange (ETDEWEB)

    Abhari, Ramin [Renewable Energy Group

    2015-08-06

    A low-cost PCM process consisting of conversion of fats and oils to PCM-range paraffins, and subsequent “encapsulation” of the paraffin using conventional plastic compounding/pelletizing equipment was demonstrated. The PCM pellets produced were field-tested in a building envelope application. This involved combining the PCM pellets with cellulose insulation, whereby 33% reduction in peak heat flux and 12% reduction in heat gain was observed (average summertime performance). The selling price of the PCM pellets produced according to this low-cost process is expected to be in the $1.50-$3.00/lb range, compared to current encapsulated PCM price of about $7.00/lb. Whole-building simulations using corresponding PCM thermal analysis data suggest a payback time of 8 to 16 years (at current energy prices) for an attic insulation retrofit project in the Phoenix climate area.

  6. Nuclear envelope and genome interactions in cell fate

    Science.gov (United States)

    Talamas, Jessica A.; Capelson, Maya

    2015-01-01

    The eukaryotic cell nucleus houses an organism’s genome and is the location within the cell where all signaling induced and development-driven gene expression programs are ultimately specified. The genome is enclosed and separated from the cytoplasm by the nuclear envelope (NE), a double-lipid membrane bilayer, which contains a large variety of trans-membrane and associated protein complexes. In recent years, research regarding multiple aspects of the cell nucleus points to a highly dynamic and coordinated concert of efforts between chromatin and the NE in regulation of gene expression. Details of how this concert is orchestrated and how it directs cell differentiation and disease are coming to light at a rapid pace. Here we review existing and emerging concepts of how interactions between the genome and the NE may contribute to tissue specific gene expression programs to determine cell fate. PMID:25852741

  7. Complex envelope control of pulsed accelerating fields in superconducting cavities

    CERN Document Server

    Czarski, T

    2010-01-01

    A digital control system for superconducting cavities of a linear accelerator is presented in this work. FPGA (Field Programmable Gate Arrays) based controller, managed by MATLAB, was developed to investigate a novel firmware implementation. The LLRF - Low Level Radio Frequency system for FLASH project in DESY is introduced. Essential modeling of a cavity resonator with signal and power analysis is considered as a key approach to the control methods. An electrical model is represented by the non-stationary state space equation for the complex envelope of the cavity voltage driven by the current generator and the beam loading. The electromechanical model of the superconducting cavity resonator including the Lorentz force detuning has been developed for a simulation purpose. The digital signal processing is proposed for the field vector detection. The field vector sum control is considered for multiple cavities driven by one klystron. An algebraic, complex domain model is proposed for the system analysis. The c...

  8. Solubilization of glycoproteins of envelope viruses by detergents

    International Nuclear Information System (INIS)

    Berezin, V.E.; Zaides, V.M.; Artamsnov, A.F.; Isaeva, E.S.; Zhdanov, V.M.

    1986-01-01

    The action of a number of known ionic and nonionic detergents, as well as the new nonionic detergent MESK, on envelope viruses was investigated. It was shown that the nonionic detergents MESK, Triton X-100, and octyl-β-D-glucopyranoside selectively solubilize the outer glycoproteins of the virus particles. The nonionic detergent MESK has the mildest action. Using MESK, purified glycoproteins of influenza, parainfluenza, Venezuelan equine encephalomyelitis, vesicular stomatitis, rabies, and herpes viruses were obtained. The procedure for obtaining glycoproteins includes incubation of the virus suspension with the detergent MESK, removal of subvirus structures by centrifuging, and purification of glycoproteins from detergents by dialysis. Isolated glycoproteins retain a native structure and biological activity and possess high immunogenicity. The detergent MESK is promising for laboratory tests and with respect to the production of subunit vaccines

  9. Rapidly evolving zona pellucida domain proteins are a major component of the vitelline envelope of abalone eggs

    Science.gov (United States)

    Aagaard, Jan E.; Yi, Xianhua; MacCoss, Michael J.; Swanson, Willie J.

    2006-01-01

    Proteins harboring a zona pellucida (ZP) domain are prominent components of vertebrate egg coats. Although less well characterized, the egg coat of the non-vertebrate marine gastropod abalone (Haliotis spp.) is also known to contain a ZP domain protein, raising the possibility of a common molecular basis of metazoan egg coat structures. Egg coat proteins from vertebrate as well as non-vertebrate taxa have been shown to evolve under positive selection. Studied most extensively in the abalone system, coevolution between adaptively diverging egg coat and sperm proteins may contribute to the rapid development of reproductive isolation. Thus, identifying the pattern of evolution among egg coat proteins is important in understanding the role these genes may play in the speciation process. The purpose of the present study is to characterize the constituent proteins of the egg coat [vitelline envelope (VE)] of abalone eggs and to provide preliminary evidence regarding how selection has acted on VE proteins during abalone evolution. A proteomic approach is used to match tandem mass spectra of peptides from purified VE proteins with abalone ovary EST sequences, identifying 9 of 10 ZP domain proteins as components of the VE. Maximum likelihood models of codon evolution suggest positive selection has acted among a subset of amino acids for 6 of these genes. This work provides further evidence of the prominence of ZP proteins as constituents of the egg coat, as well as the prominent role of positive selection in diversification of these reproductive proteins. PMID:17085584

  10. Analysis of beam envelope by transverse space charge effect

    International Nuclear Information System (INIS)

    Toyama, Shin'ichi

    1997-09-01

    It is important for high current accelerators to estimate the contribution of the space charge effect to keep the beam off its beak up. The application of an envelope equation is examined in previous report in which the beam is just coasting beam (non accelerating). The analysis of space charge effect is necessary for the comparison in coming accelerator test in PNC. In order to evaluate the beam behavior in high current, the beam dynamics and beam parameters which are input to the equation for the evaluation are developed and make it ready to estimate the beam transverse dynamics by the space charge. The estimate needs to have enough accuracy for advanced code calculation. After the preparation of the analytic expression of transverse motion, the non-linear differential equation of beam dynamics is solved by a numerical method on a personal computer. The beam envelope from the equation is estimated by means of the beam emittance, current and energy. The result from the analysis shows that the transverse beam broadening is scarecely small around the beam current value of PNC design. The contribution to the beam broadening of PNC linac comes from its beam emittance. The beam broadening in 100 MeV case is almost negligible in the view of transverse space charge effect. Therefore, the electron beam is stable up to 10 A order in PNC linac design. Of course, the problem for RF supply is out of consideration here. It is important to estimate other longitudinal effect such as beam bunch effect which is lasting unevaluated. (author)

  11. Ejection of the Massive Hydrogen-rich Envelope Timed with the Collapse of the Stripped SN 2014C

    Energy Technology Data Exchange (ETDEWEB)

    Margutti, Raffaella [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Kamble, A.; Milisavljevic, D.; Drout, M.; Chakraborti, S.; Kirshner, R.; Parrent, J. T.; Patnaude, D.; Soderberg, A. M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Zapartas, E.; De Mink, S. E. [Anton Pannenkoek Institute for Astronomy, University of Amsterdam, 1090 GE Amsterdam (Netherlands); Chornock, R. [Astrophysical Institute, Department of Physics and Astronomy, 251B Clippinger Lab, Ohio University, Athens, OH 45701 (United States); Risaliti, G. [INAF-Arcetri Astrophysical Observatory, Largo E. Fermi 5, I-50125 Firenze (Italy); Zauderer, B. A. [Center for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Bietenholz, M. [Department of Physics and Astronomy, York University, Toronto, ON M3J 1P3 (Canada); Cantiello, M. [Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106 (United States); Chomiuk, L. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Fong, W. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Grefenstette, B. [Cahill Center for Astrophysics, 1216 E. California Boulevard, California Institute of Technology, Pasadena, CA 91125 (United States); Guidorzi, C. [University of Ferrara, Department of Physics and Earth Sciences, via Saragat 1, I-44122 Ferrara (Italy); and others

    2017-02-01

    We present multi-wavelength observations of SN 2014C during the first 500 days. These observations represent the first solid detection of a young extragalactic stripped-envelope SN out to high-energy X-rays ∼40 keV. SN 2014C shows ordinary explosion parameters ( E {sub k} ∼ 1.8 × 10{sup 51} erg and M {sub ej} ∼ 1.7 M{sub ⊙}). However, over an ∼1 year timescale, SN 2014C evolved from an ordinary hydrogen-poor supernova into a strongly interacting, hydrogen-rich supernova, violating the traditional classification scheme of type-I versus type-II SNe. Signatures of the SN shock interaction with a dense medium are observed across the spectrum, from radio to hard X-rays, and revealed the presence of a massive shell of ∼1 M {sub ⊙} of hydrogen-rich material at ∼6 × 10{sup 16} cm. The shell was ejected by the progenitor star in the decades to centuries before collapse. This result challenges current theories of massive star evolution, as it requires a physical mechanism responsible for the ejection of the deepest hydrogen layer of H-poor SN progenitors synchronized with the onset of stellar collapse. Theoretical investigations point at binary interactions and/or instabilities during the last nuclear burning stages as potential triggers of the highly time-dependent mass loss. We constrain these scenarios utilizing the sample of 183 SNe Ib/c with public radio observations. Our analysis identifies SN 2014C-like signatures in ∼10% of SNe. This fraction is reasonably consistent with the expectation from the theory of recent envelope ejection due to binary evolution if the ejected material can survive in the close environment for 10{sup 3}–10{sup 4} years. Alternatively, nuclear burning instabilities extending to core C-burning might play a critical role.

  12. Identification of new genes in a cell envelope-cell division gene cluster of Escherichia coli: cell envelope gene murG.

    Science.gov (United States)

    Salmond, G P; Lutkenhaus, J F; Donachie, W D

    1980-01-01

    We report the identification, cloning, and mapping of a new cell envelope gene, murG. This lies in a group of five genes of similar phenotype (in the order murE murF murG murC ddl) all concerned with peptidoglycan biosynthesis. This group is in a larger cluster of at least 10 genes, all of which are involved in some way with cell envelope growth. Images PMID:6998962

  13. Inability of keratinocytes lacking their specific transglutaminase to form cross-linked envelopes: Absence of envelopes as a simple diagnostic test for lamellar ichthyosis

    OpenAIRE

    Jeon, Saewha; Djian, Philippe; Green, Howard

    1998-01-01

    Epidermal keratinocytes, late in their terminal differentiation, form cross-linked envelopes resistant to ionic detergent and reducing agent. Because the cross-linking process is catalyzed by the keratinocyte transglutaminase, the absence of active transglutaminase should result in failure of the keratinocyte to form a cross-linked envelope. Three keratinocyte strains bearing mutations in the keratinocyte transglutaminase were examined: two contained no detectable transglutaminase mRNA and no...

  14. Nonlinear evolution of astrophysical Alfven waves

    Science.gov (United States)

    Spangler, S. R.

    1984-01-01

    Nonlinear Alfven waves were studied using the derivative nonlinear Schrodinger equation as a model. The evolution of initial conditions, such as envelope solitons, amplitude-modulated waves, and band-limited noise was investigated. The last two furnish models for naturally occurring Alfven waves in an astrophysical plasma. A collapse instability in which a wave packet becomes more intense and of smaller spatial extent was analyzed. It is argued that this instability leads to enhanced plasma heating. In studies in which the waves are amplified by an electron beam, the instability tends to modestly inhibit wave growth.

  15. Instrument for measuring flow velocities

    International Nuclear Information System (INIS)

    Griffo, J.

    1977-01-01

    The design described here means to produce a 'more satisfying instrument with less cost' than comparable instruments known up to now. Instead of one single turbine rotor, two similar ones but with opposite blade inclination and sense of rotation are to be used. A cylindrical measuring body is carrying in its axis two bearing blocks whose shape is offering little flow resistance. On the shaft, supported by them, the two rotors run in opposite direction a relatively small axial distance apart. The speed of each rotor is picked up as pulse recurrence frequency by a transmitter and fed to an electronic measuring unit. Measuring errors as they are caused for single rotors by turbulent flow, profile distortion of the velocity, or viscous flow are to be eliminated by means of the contrarotating turbines and the subsequently added electronic unit, because in these cases the adulterating increase of the angular velocity of one rotor is compensated by a corresponding deceleration of the other rotor. The mean value then indicated by the electronic unit has high accurancy of measurement. (RW) [de

  16. A Python Calculator for Supernova Remnant Evolution

    Science.gov (United States)

    Leahy, D. A.; Williams, J. E.

    2017-05-01

    A freely available Python code for modeling supernova remnant (SNR) evolution has been created. This software is intended for two purposes: to understand SNR evolution and to use in modeling observations of SNR for obtaining good estimates of SNR properties. It includes all phases for the standard path of evolution for spherically symmetric SNRs. In addition, alternate evolutionary models are available, including evolution in a cloudy ISM, the fractional energy-loss model, and evolution in a hot low-density ISM. The graphical interface takes in various parameters and produces outputs such as shock radius and velocity versus time, as well as SNR surface brightness profile and spectrum. Some interesting properties of SNR evolution are demonstrated using the program.

  17. Critical Velocity for Shear Localization in A Mature Mylonitic Rock Analogue

    Science.gov (United States)

    Takahashi, M.; van den Ende, M.; Niemeijer, A. R.; Spiers, C. J.

    2016-12-01

    Highly localized slip zones, seen within ductile shear zones developed in nature, such as pseudotachylite bands occurring within mylonites, are widely recognized as evidence for earthquake nucleation and/or propagation within and overprinting the ductile regime. To understand brittle/frictional localization processes in ductile shear zones and to connect these to earthquake nucleation and propagation processes, we performed large velocity step-change tests on a brine-saturated, 80:20 (wt. %) halite and muscovite gouge mixture, after forming a mature mylonitic structure through pressure solution creep at low-velocity. The sharp increase in sliding strength that occurs in response to an instantaneous upward velocity-step (direct effect) is an important parameter in determining the potential for and nature of seismic rupture nucleation. We obtained reproducible results regarding low velocity mechanical behavior compared with previous work of Niemeijer and Spiers, [2006], but also obtained new insights into the effects of sudden increases in slip velocity on localization and strength evolution, at velocities above a specific critical velocity Vc ( 20 μm/sec). We found that once a ductile, mylonitic structure has developed in a shear zone, subsequent cataclastic deformation at high velocity (> Vc) is consistently localized in a narrow zone characterized by fine grains of halite aligned in arrays between foliated muscovite Due to this intense localization, structures presumably developed under low velocity conditions were still preserved in large parts of the gouge body. This switch to localized deformation is controlled by the imposed velocity, and becomes most apparent at velocities over Vc. In addition, the direct effect a decreases rapidly when the velocity exceeds Vc. This implies that slip can localize and accelerate towards seismic velocities more or less instantly once Vc is exceeded. Obtaining a measure for Vc in natural faults is therefore of key importance

  18. Low velocity encounters of minor bodies with the outer planets

    International Nuclear Information System (INIS)

    Carusi, A.; Perozzi, E.; Valsecchi, G.B.

    1983-01-01

    Previous studies of close encounters of minor bodies with Jupiter have shown that the perturbations are stronger either if the encounter is very deep or if the velocity of the minor body relative to the planet is low. In the present research the author investigates the effects of low velocity encounters between fictitious minor bodies and the four outer planets. Two possible outcomes of this type of encounter are the temporary satellite capture of the minor body by the planet, and the exchange of perihelion with aphelion of the minor body orbit. Different occurrence rates of these processes are found for different planets, and the implications for the orbital evolution of minor bodies in the outer Solar System are discussed. (Auth.)

  19. Stochastic spin evolution of neutron stars

    OpenAIRE

    Popov, S. B.; Prokhorov, M. E.; Khoperskov, A. V.; Lipunov, V. M.

    2001-01-01

    In this paper we present calculations of period distribution for old accreting isolated neutron stars (INSs). At the age about a few billions years low velocity INSs come to the stage of accretion. At that stage their period evolution is governed by magnetic breaking and accreted angular momentum. Due to turbulence of the interstellar medium (ISM) accreted momentum can both accelerate and decelerate rotation of an INS and spin evolution has chaotic character. Calculations show that for consta...

  20. Enhancement of feline immunodeficiency virus infection after immunization with envelope glycoprotein subunit vaccines.

    NARCIS (Netherlands)

    C.H.J. Siebelink (Kees); E.J. Tijhaar (Edwin); R.C. Huisman (Robin); W. Huisman (Willem); A. de Ronde; I.H. Darby; M.J. Francis; G.F. Rimmelzwaan (Guus); A.D.M.E. Osterhaus (Albert)

    1995-01-01

    textabstractCats were immunized three times with different recombinant feline immunodeficiency virus (FIV) candidate vaccines. Recombinant vaccinia virus (rVV)-expressed envelope glycoprotein with (vGR657) or without (vGR657 x 15) the cleavage site and an FIV envelope bacterial fusion protein

  1. Implementation of Models for Building Envelope Air Flow Fields in a Whole Building Hygrothermal Simulation Tool

    DEFF Research Database (Denmark)

    Sørensen, Karl Grau; Rode, Carsten

    2009-01-01

    cavity such as behind the exterior cladding of a building envelope, i.e. a flow which is parallel to the construction plane. (2) Infiltration/exfiltration of air through the building envelope, i.e. a flow which is perpendicular to the constructionplane. The paper presents the models and how they have...

  2. Effects of radial envelope modulations on the collisionless trapped-electron mode in tokamak plasmas

    Science.gov (United States)

    Chen, Hao-Tian; Chen, Liu

    2018-05-01

    Adopting the ballooning-mode representation and including the effects of radial envelope modulations, we have derived the corresponding linear eigenmode equation for the collisionless trapped-electron mode in tokamak plasmas. Numerical solutions of the eigenmode equation indicate that finite radial envelope modulations can affect the linear stability properties both quantitatively and qualitatively via the significant modifications in the corresponding eigenmode structures.

  3. Bursting the Bubble - Nuclear Envelope Rupture as a Path to Genomic Instability?

    NARCIS (Netherlands)

    Shah, P.; Wolf, K.A.; Lammerding, J.

    2017-01-01

    The nuclear envelope safeguards the genetic material inside the nucleus by separating it from the cytoplasm. Until recently, it was assumed that nuclear envelope (NE) breakdown occurs only in a highly controlled fashion during mitosis when the chromatin is condensed and divided between the daughter

  4. 47 CFR 25.218 - Off-axis EIRP envelopes for FSS earth station operations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Off-axis EIRP envelopes for FSS earth station operations. 25.218 Section 25.218 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.218 Off-axis EIRP envelopes for FSS...

  5. Efficiency Enhancement of an Envelope Tracking Power Amplifier Combining Supply Shaping and Dynamic Biasing

    DEFF Research Database (Denmark)

    Tafuri, Felice Francesco; Sira, Daniel; Jensen, Ole Kiel

    2013-01-01

    This paper presents a new method to improve the performance of envelope tracking (ET) power amplifiers (PAs). The method consists of combining the supply modulation that characterizes the envelope tracking architecture with supply shaping and dynamic biasing. The inclusion of dynamic biasing allo...

  6. Design and evaluation of a Flight Envelope Protection haptic feedback system

    NARCIS (Netherlands)

    Ellerbroek, J.; Rodriguez Martin, M.J.M.; Lombaerts, T; van Paassen, M.M.; Mulder, M.

    2016-01-01

    This paper describes the design and evaluation of a shared control, haptic feedback system to communicate Flight Envelope Protection System intent. The concept uses a combination of stiffness feedback and vibration to communicate proximity of the aircraft state to flight envelope boundaries. In

  7. Analyzing energy consumption while heating one-layer building envelopes in conditions of intermittent heating

    Directory of Open Access Journals (Sweden)

    Vytchikov Yury

    2017-01-01

    Full Text Available This paper focuses on energy consumption for heating single layer building envelopes, used in conditions of intermittent heating in different physical and mechanical and thermophysical parameters of construction materials. The authors investigated several variants of single-layer building envelopes, used frequently in building practice, with different density and coefficients of building materials thermal conductivity. For each variant of a building envelope heat leakage and time spent on heating were calculated. Heating time was calculated by both exact and approximate analytical method. Then the researchers draw a graphic dependence of energy consumption on the density of the material taking this computational data as a basis. Further analysis showed that building envelopes made of lightweight aggregate concrete and porous concrete were the most energy efficient.This paper focuses on energy consumption for heating single layer building envelopes, used in conditions of intermittent heating in different physical and mechanical and thermophysical parameters of construction materials. The authors investigated several variants of single-layer building envelopes, used frequently in building practice, with different density and coefficients of building materials thermal conductivity. For each variant of a building envelope heat leakage and time spent on heating were calculated. Heating time was calculated by both exact and approximate analytical method. Then the researchers draw a graphic dependence of energy consumption on the density of the material taking this computational data as a basis. Further analysis showed that building envelopes made of lightweight aggregate concrete and porous concrete were the most energy efficient.

  8. Advancing the manufacture of complex geometry GFRC for today's building envelopes

    Directory of Open Access Journals (Sweden)

    Thomas Henriksen

    2017-06-01

    With this research the current architectural knowledge base has been advanced in terms of complex geometry thin-walled GFRC for building envelopes. The identified solutions should allow building with complex geometries to be realised using thin-walled GFRC as the envelope cladding.

  9. Protamine-induced permeabilization of cell envelopes of gram-positive and gram-negative bacteria

    DEFF Research Database (Denmark)

    Johansen, Charlotte; Verheul, A.; Gram, Lone

    1997-01-01

    carboxyfluorescein and ATP after 2 to 5 min. Maximum antibacterial activity was reached at alkaline pH and in the absence of divalent cations. The efficient permeabilization of cell envelopes of both gram-positive and gram-negative bacteria suggests that protamine causes a general disruption of the cell envelope...

  10. Incipient failure detection of space shuttle main engine turbopump bearings using vibration envelope detection

    Science.gov (United States)

    Hopson, Charles B.

    1987-01-01

    The results of an analysis performed on seven successive Space Shuttle Main Engine (SSME) static test firings, utilizing envelope detection of external accelerometer data are discussed. The results clearly show the great potential for using envelope detection techniques in SSME incipient failure detection.

  11. On the relationship between multi-channel envelope and temporal fine structure

    DEFF Research Database (Denmark)

    Søndergaard, Peter Lempel; Decorsiere, Remi Julien Blaise; Dau, Torsten

    2011-01-01

    The envelope of a signal is broadly defined as the slow changes in time of the signal, where as the temporal fine structure (TFS) are the fast changes in time, i.e. the carrier wave(s) of the signal. The focus of this paper is on envelope and TFS in multi-channel systems. We discuss the differenc...

  12. Intermittent Lagrangian velocities and accelerations in three-dimensional porous medium flow.

    Science.gov (United States)

    Holzner, M; Morales, V L; Willmann, M; Dentz, M

    2015-07-01

    Intermittency of Lagrangian velocity and acceleration is a key to understanding transport in complex systems ranging from fluid turbulence to flow in porous media. High-resolution optical particle tracking in a three-dimensional (3D) porous medium provides detailed 3D information on Lagrangian velocities and accelerations. We find sharp transitions close to pore throats, and low flow variability in the pore bodies, which gives rise to stretched exponential Lagrangian velocity and acceleration distributions characterized by a sharp peak at low velocity, superlinear evolution of particle dispersion, and double-peak behavior in the propagators. The velocity distribution is quantified in terms of pore geometry and flow connectivity, which forms the basis for a continuous-time random-walk model that sheds light on the observed Lagrangian flow and transport behaviors.

  13. Application of Vectors to Relative Velocity

    Science.gov (United States)

    Tin-Lam, Toh

    2004-01-01

    The topic 'relative velocity' has recently been introduced into the Cambridge Ordinary Level Additional Mathematics syllabus under the application of Vectors. In this note, the results of relative velocity and the 'reduction to rest' technique of teaching relative velocity are derived mathematically from vector algebra, in the hope of providing…

  14. Questions Students Ask: About Terminal Velocity.

    Science.gov (United States)

    Meyer, Earl R.; Nelson, Jim

    1984-01-01

    If a ball were given an initial velocity in excess of its terminal velocity, would the upward force of air resistance (a function of velocity) be greater than the downward force of gravity and thus push the ball back upwards? An answer to this question is provided. (JN)

  15. Balance velocities of the Greenland ice sheet

    DEFF Research Database (Denmark)

    Joughin, I.; Fahnestock, M.; Ekholm, Simon

    1997-01-01

    We present a map of balance velocities for the Greenland ice sheet. The resolution of the underlying DEM, which was derived primarily from radar altimetery data, yields far greater detail than earlier balance velocity estimates for Greenland. The velocity contours reveal in striking detail......, the balance map is useful for ice-sheet modelling, mass balance studies, and field planning....

  16. The RRc Stars: Chemical Abundances and Envelope Kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Sneden, Christopher; Adamów, Monika [Department of Astronomy and McDonald Observatory, The University of Texas, Austin, TX 78712 (United States); Preston, George W. [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Chadid, Merieme, E-mail: chris@verdi.as.utexas.edu, E-mail: astromysz@gmail.com, E-mail: gwp@obs.carnegiescience.edu, E-mail: chadid@unice.fr [Université Nice Sophia–Antipolis, Observatoire de la Côte dAzur, UMR 7293, Parc Valrose, F-06108, Nice Cedex 02 (France)

    2017-10-10

    We analyzed series of spectra obtained for 12 stable RRc stars observed with the echelle spectrograph of the du Pont telescope at Las Campanas Observatory and we analyzed the spectra of RRc Blazhko stars discussed by Govea et al. We derived model atmosphere parameters, [Fe/H] metallicities, and [X/Fe] abundance ratios for 12 species of 9 elements. We co-added all spectra obtained during the pulsation cycles to increase signal to noise and demonstrate that these spectra give results superior to those obtained by co-addition in small phase intervals. The RRc abundances are in good agreement with those derived for the RRab stars of Chadid et al. We used radial velocity (RV) measurements of metal lines and H α to construct variations of velocity with phase, and center-of-mass velocities. We used these to construct RV templates for use in low- to medium-resolution RV surveys of RRc stars. Additionally, we calculated primary accelerations, radius variations, and metal and H α velocity amplitudes, which we display as regressions against primary acceleration. We employ these results to compare the atmosphere structures of metal-poor RRc stars with their RRab counterparts. Finally, we use the RV data for our Blazhko stars and the Blazhko periods of Szczygieł and Fabrycky to falsify the Blazhko oblique rotator hypothesis.

  17. Critical velocities in He II for independently varied superfluid and normal fluid velocities

    International Nuclear Information System (INIS)

    Baehr, M.L.

    1984-01-01

    Experiments were performed to measure the critical velocity in pure superflow and compare to the theoretical prediction; to measure the first critical velocity for independently varied superfluid and normal fluid velocities; and to investigate the propagation of the second critical velocity from the thermal counterflow line through the V/sub n/,-V/sub s/ quadrant. The experimental apparatus employed a thermal counterflow heater to adjust the normal fluid velocity, a fountain pump to vary the superfluid velocity, and a level sensing capacitor to measure the superfluid velocity. The results of the pure superfluid critical velocity measurements indicate that this velocity is temperature independent contrary to Schwarz's theory. It was found that the first critical velocity for independently varied V/sub n/ and V/sub s/ could be described by a linear function of V/sub n/ and was otherwise temperature independent. It was found that the second critical velocity could only be distinguished near the thermal counterflow line

  18. A High Mass & Low Envelope Fraction for the Warm Neptune K2-55b

    Science.gov (United States)

    Dressing, Courtney; Sinukoff, Evan; Fulton, Benjamin; Lopez, Eric; Beichman, Charles; Howard, Andrew; Knutson, Heather; Werner, Michael; Schlieder, Joshua; Benneke, Björn; Crossfield, Ian; Isaacson, Howard; Krick, Jessica; Gorjian, Varoujan; Livingston, John; Petigura, Erik; Akeson, Rachel; Batygin, Konstantin; Christiansen, Jessie; Ciardi, David; Crepp, Justin; Jasmine Gonzales, Erica; Hardegree-Ullman, Kevin; Hirsch, Lea; Kosiarek, Molly; Weiss, Lauren

    2018-01-01

    The NASA K2 mission is using the Kepler spacecraft to search for transiting planets in multiple fields along the ecliptic plane. One of the planets detected by K2 is K2-55b, a warm Neptune in a short-period orbit (2.8 days) around a late K dwarf. We previously obtained near-infrared spectra from IRTF/SpeX to characterize the system and found that the host star K2-55 has a radius of 0.715 (+0.043/-0.040) solar radii, a mass of 0.668 (+/- 0.069) solar masses, and an effective temperature of 4300K (+100/-107). We then combined our updated stellar properties with new fits to the K2 photometry to estimate a planet radius of 4.38 (+0.29/-0.25) Earth radii, confirmed the transit ephemeris using Spitzer/IRAC (GO 11026, PI Werner), and embarked on radial velocity observations with Keck/HIRES to measure the planet mass. Our RV data suggest that K2-55b is much more massive than expected, indicating that the planet has a high density despite having a relatively high mass. The lack of a significant volatile envelope tests current theories of gas giant formation and indicates that K2-55b may have avoided runaway accretion by migration, delayed formation, or inefficient core accretion. We gratefully acknowledge funding from the NASA Sagan Fellowship Program and the NASA K2 Guest Observer Program. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech.

  19. Animal evolution

    DEFF Research Database (Denmark)

    Nielsen, Claus

    This book provides a comprehensive analysis of evolution in the animal kingdom. It reviews the classical, morphological information from structure and embryology, as well as the new data gained from studies using immune stainings of nerves and muscles and blastomere markings, which makes it possi......This book provides a comprehensive analysis of evolution in the animal kingdom. It reviews the classical, morphological information from structure and embryology, as well as the new data gained from studies using immune stainings of nerves and muscles and blastomere markings, which makes...

  20. Rayleigh and Love Wave Phase Velocities in the Northern Gulf Coast of the United States

    Science.gov (United States)

    Li, A.; Yao, Y.

    2017-12-01

    The last major tectonic event in the northern Gulf Coast of the United States is Mesozoic continental rifting that formed the Gulf of Mexico. This area also experienced igneous activity and local uplifts during Cretaceous. To investigate lithosphere evolution associated with the rifting and igneous activity, we construct Rayleigh and Love wave phase velocity models at the periods of 6 s to 125 s in the northern Gulf Coast from Louisiana to Alabama including the eastern Ouachita and southern Appalachian orogeny. The phase velocities are derived from ambient noise and earthquake data recorded at the 120 USArray Transportable Array stations. At periods below 20 s, phase velocity maps are characterized by significant low velocities in the Interior Salt Basin and Gulf Coast Basin, reflecting the effects of thick sediments. The northern Louisiana and southern Arkansas are imaged as a low velocity anomaly in Rayleigh wave models but a high velocity anomaly of Love wave at the periods of 14 s to 30 s, indicating strong lower crust extension to the Ouachita front. High velocity is present in the Mississippi Valley Graben from period 20 s to 35 s, probably reflecting a thin crust or high-velocity lower crust. At longer periods, low velocities are along the Mississippi River to the Gulf Coast Basin, and high velocity anomaly mainly locates in the Black Warrior Basin between the Ouachita Belt and Appalachian Orogeny. The magnitude of anomalies in Love wave images is much smaller than that in Rayleigh wave models, which is probably due to radial anisotropy in the upper mantle. A 3-D anisotropic shear velocity model will be developed from the phase velocities and will provide more details for the crust and upper mantle structure beneath the northern Gulf of Mexico continental margin.

  1. A Functional Henipavirus Envelope Glycoprotein Pseudotyped Lentivirus Assay System

    Directory of Open Access Journals (Sweden)

    Broder Christopher C

    2010-11-01

    Full Text Available Abstract Background Hendra virus (HeV and Nipah virus (NiV are newly emerged zoonotic paramyxoviruses discovered during outbreaks in Queensland, Australia in 1994 and peninsular Malaysia in 1998/9 respectively and classified within the new Henipavirus genus. Both viruses can infect a broad range of mammalian species causing severe and often-lethal disease in humans and animals, and repeated outbreaks continue to occur. Extensive laboratory studies on the host cell infection stage of HeV and NiV and the roles of their envelope glycoproteins have been hampered by their highly pathogenic nature and restriction to biosafety level-4 (BSL-4 containment. To circumvent this problem, we have developed a henipavirus envelope glycoprotein pseudotyped lentivirus assay system using either a luciferase gene or green fluorescent protein (GFP gene encoding human immunodeficiency virus type-1 (HIV-1 genome in conjunction with the HeV and NiV fusion (F and attachment (G glycoproteins. Results Functional retrovirus particles pseudotyped with henipavirus F and G glycoproteins displayed proper target cell tropism and entry and infection was dependent on the presence of the HeV and NiV receptors ephrinB2 or B3 on target cells. The functional specificity of the assay was confirmed by the lack of reporter-gene signals when particles bearing either only the F or only G glycoprotein were prepared and assayed. Virus entry could be specifically blocked when infection was carried out in the presence of a fusion inhibiting C-terminal heptad (HR-2 peptide, a well-characterized, cross-reactive, neutralizing human mAb specific for the henipavirus G glycoprotein, and soluble ephrinB2 and B3 receptors. In addition, the utility of the assay was also demonstrated by an examination of the influence of the cytoplasmic tail of F in its fusion activity and incorporation into pseudotyped virus particles by generating and testing a panel of truncation mutants of NiV and HeV F

  2. Characterizing Functional Domains for TIM-Mediated Enveloped Virus Entry

    Science.gov (United States)

    Moller-Tank, Sven; Albritton, Lorraine M.; Rennert, Paul D.

    2014-01-01

    ABSTRACT T-cell immunoglobulin and mucin domain 1 (TIM-1) and other TIM family members were recently identified as phosphatidylserine (PtdSer)-mediated virus entry-enhancing receptors (PVEERs). These proteins enhance entry of Ebola virus (EBOV) and other viruses by binding PtdSer on the viral envelope, concentrating virus on the cell surface, and promoting subsequent internalization. The PtdSer-binding activity of the immunoglobulin-like variable (IgV) domain is essential for both virus binding and internalization by TIM-1. However, TIM-3, whose IgV domain also binds PtdSer, does not effectively enhance virus entry, indicating that other domains of TIM proteins are functionally important. Here, we investigate the domains supporting enhancement of enveloped virus entry, thereby defining the features necessary for a functional PVEER. Using a variety of chimeras and deletion mutants, we found that in addition to a functional PtdSer-binding domain PVEERs require a stalk domain of sufficient length, containing sequences that promote an extended structure. Neither the cytoplasmic nor the transmembrane domain of TIM-1 is essential for enhancing virus entry, provided the protein is still plasma membrane bound. Based on these defined characteristics, we generated a mimic lacking TIM sequences and composed of annexin V, the mucin-like domain of α-dystroglycan, and a glycophosphatidylinositol anchor that functioned as a PVEER to enhance transduction of virions displaying Ebola, Chikungunya, Ross River, or Sindbis virus glycoproteins. This identification of the key features necessary for PtdSer-mediated enhancement of virus entry provides a basis for more effective recognition of unknown PVEERs. IMPORTANCE T-cell immunoglobulin and mucin domain 1 (TIM-1) and other TIM family members are recently identified phosphatidylserine (PtdSer)-mediated virus entry-enhancing receptors (PVEERs). These proteins enhance virus entry by binding the phospholipid, PtdSer, present on the viral

  3. Polymers in cell encapsulation from an enveloped cell perspective.

    Science.gov (United States)

    de Vos, Paul; Lazarjani, Hamideh Aghajani; Poncelet, Denis; Faas, Marijke M

    2014-04-01

    In the past two decades, many polymers have been proposed for producing immunoprotective capsules. Examples include the natural polymers alginate, agarose, chitosan, cellulose, collagen, and xanthan and synthetic polymers poly(ethylene glycol), polyvinyl alcohol, polyurethane, poly(ether-sulfone), polypropylene, sodium polystyrene sulfate, and polyacrylate poly(acrylonitrile-sodium methallylsulfonate). The biocompatibility of these polymers is discussed in terms of tissue responses in both the host and matrix to accommodate the functional survival of the cells. Cells should grow and function in the polymer network as adequately as in their natural environment. This is critical when therapeutic cells from scarce cadaveric donors are considered, such as pancreatic islets. Additionally, the cell mass in capsules is discussed from the perspective of emerging new insights into the release of so-called danger-associated molecular pattern molecules by clumps of necrotic therapeutic cells. We conclude that despite two decades of intensive research, drawing conclusions about which polymer is most adequate for clinical application is still difficult. This is because of the lack of documentation on critical information, such as the composition of the polymer, the presence or absence of confounding factors that induce immune responses, toxicity to enveloped cells, and the permeability of the polymer network. Only alginate has been studied extensively and currently qualifies for application. This review also discusses critical issues that are not directly related to polymers and are not discussed in the other reviews in this issue, such as the functional performance of encapsulated cells in vivo. Physiological endocrine responses may indeed not be expected because of the many barriers that the metabolites encounter when traveling from the blood stream to the enveloped cells and back to circulation. However, despite these diffusion barriers, many studies have shown optimal

  4. Condensins Exert Force on Chromatin-Nuclear Envelope Tethers to Mediate Nucleoplasmic Reticulum Formation in Drosophila melanogaster

    Science.gov (United States)

    Bozler, Julianna; Nguyen, Huy Q.; Rogers, Gregory C.; Bosco, Giovanni

    2014-01-01

    Although the nuclear envelope is known primarily for its role as a boundary between the nucleus and cytoplasm in eukaryotes, it plays a vital and dynamic role in many cellular processes. Studies of nuclear structure have revealed tissue-specific changes in nuclear envelope architecture, suggesting that its three-dimensional structure contributes to its functionality. Despite the importance of the nuclear envelope, the factors that regulate and maintain nuclear envelope shape remain largely unexplored. The nuclear envelope makes extensive and dynamic interactions with the underlying chromatin. Given this inexorable link between chromatin and the nuclear envelope, it is possible that local and global chromatin organization reciprocally impact nuclear envelope form and function. In this study, we use Drosophila salivary glands to show that the three-dimensional structure of the nuclear envelope can be altered with condensin II-mediated chromatin condensation. Both naturally occurring and engineered chromatin-envelope interactions are sufficient to allow chromatin compaction forces to drive distortions of the nuclear envelope. Weakening of the nuclear lamina further enhanced envelope remodeling, suggesting that envelope structure is capable of counterbalancing chromatin compaction forces. Our experiments reveal that the nucleoplasmic reticulum is born of the nuclear envelope and remains dynamic in that they can be reabsorbed into the nuclear envelope. We propose a model where inner nuclear envelope-chromatin tethers allow interphase chromosome movements to change nuclear envelope morphology. Therefore, interphase chromatin compaction may be a normal mechanism that reorganizes nuclear architecture, while under pathological conditions, such as laminopathies, compaction forces may contribute to defects in nuclear morphology. PMID:25552604

  5. Condensins exert force on chromatin-nuclear envelope tethers to mediate nucleoplasmic reticulum formation in Drosophila melanogaster.

    Science.gov (United States)

    Bozler, Julianna; Nguyen, Huy Q; Rogers, Gregory C; Bosco, Giovanni

    2014-12-30

    Although the nuclear envelope is known primarily for its role as a boundary between the nucleus and cytoplasm in eukaryotes, it plays a vital and dynamic role in many cellular processes. Studies of nuclear structure have revealed tissue-specific changes in nuclear envelope architecture, suggesting that its three-dimensional structure contributes to its functionality. Despite the importance of the nuclear envelope, the factors that regulate and maintain nuclear envelope shape remain largely unexplored. The nuclear envelope makes extensive and dynamic interactions with the underlying chromatin. Given this inexorable link between chromatin and the nuclear envelope, it is possible that local and global chromatin organization reciprocally impact nuclear envelope form and function. In this study, we use Drosophila salivary glands to show that the three-dimensional structure of the nuclear envelope can be altered with condensin II-mediated chromatin condensation. Both naturally occurring and engineered chromatin-envelope interactions are sufficient to allow chromatin compaction forces to drive distortions of the nuclear envelope. Weakening of the nuclear lamina further enhanced envelope remodeling, suggesting that envelope structure is capable of counterbalancing chromatin compaction forces. Our experiments reveal that the nucleoplasmic reticulum is born of the nuclear envelope and remains dynamic in that they can be reabsorbed into the nuclear envelope. We propose a model where inner nuclear envelope-chromatin tethers allow interphase chromosome movements to change nuclear envelope morphology. Therefore, interphase chromatin compaction may be a normal mechanism that reorganizes nuclear architecture, while under pathological conditions, such as laminopathies, compaction forces may contribute to defects in nuclear morphology. Copyright © 2015 Bozler et al.

  6. Time Variations of the Radial Velocity of H2O Masers in the Semi-Regular Variable R Crt

    Science.gov (United States)

    Sudou, Hiroshi; Shiga, Motoki; Omodaka, Toshihiro; Nakai, Chihiro; Ueda, Kazuki; Takaba, Hiroshi

    2017-12-01

    H2O maser emission {at 22 GHz} in the circumstellar envelope is one of the good tracers of detailed physics and inematics in the mass loss process of asymptotic giant branch stars. Long-term monitoring of an H2O maser spectrum with high time resolution enables us to clarify acceleration processes of the expanding shell in the stellar atmosphere. We monitored the H2O maser emission of the semi-regular variable R Crt with the Kagoshima 6-m telescope, and obtained a large data set of over 180 maser spectra over a period of 1.3 years with an observational span of a few days. Using an automatic peak detection method based on least-squares fitting, we exhaustively detected peaks as significant velocity components with the radial velocity on a 0.1 km s^{-1} scale. This analysis result shows that the radial velocity of red-shifted and blue-shifted components exhibits a change between acceleration and deceleration on the time scale of a few hundred days. These velocity variations are likely to correlate with intensity variations, in particular during flaring state of H2O masers. It seems reasonable to consider that the velocity variation of the maser source is caused by shock propagation in the envelope due to stellar pulsation.However, it is difficult to explain the relationship between the velocity variation and the intensity variation only from shock propagation effects. We found that a time delay of the integrated maser intensity with respect to the optical light curve is about 150 days.

  7. Representing Evolution

    DEFF Research Database (Denmark)

    Hedin, Gry

    2012-01-01

    . This article discusses Willumsen's etching in the context of evolutionary theory, arguing that Willumsen is a rare example of an artist who not only let the theory of evolution fuel his artistic imagination, but also concerned himself with a core issue of the theory, namely to what extent it could be applied...

  8. Security Evolution.

    Science.gov (United States)

    De Patta, Joe

    2003-01-01

    Examines how to evaluate school security, begin making schools safe, secure schools without turning them into fortresses, and secure schools easily and affordably; the evolution of security systems into information technology systems; using schools' high-speed network lines; how one specific security system was developed; pros and cons of the…

  9. Cepheid evolution

    International Nuclear Information System (INIS)

    Becker, S.A.

    1984-05-01

    A review of the phases of stellar evolution relevant to Cepheid variables of both Types I and II is presented. Type I Cepheids arise as a result of normal post-main sequence evolutionary behavior of many stars in the intermediate to massive range of stellar masses. In contrast, Type II Cepheids generally originate from low-mass stars of low metalicity which are undergoing post core helium-burning evolution. Despite great progress in the past two decades, uncertainties still remain in such areas as how to best model convective overshoot, semiconvection, stellar atmospheres, rotation, and binary evolution as well as uncertainties in important physical parameters such as the nuclear reaction rates, opacity, and mass loss rates. The potential effect of these uncertainties on stellar evolution models is discussed. Finally, comparisons between theoretical predictions and observations of Cepheid variables are presented for a number of cases. The results of these comparisons show both areas of agreement and disagreement with the latter result providing incentive for further research

  10. Venom Evolution

    Indian Academy of Sciences (India)

    IAS Admin

    Therefore, the platypus sequence was studied to quantify the role of gene duplication in the evolution of venom. ... Platypus venom is present only in males and is used for asserting dominance over com- petitors during the ... Certain toxin gene families are known to re- peatedly evolve through gene duplications. The rapidly ...

  11. Solar envelope zoning: application to the city planning process. Los Angeles case study

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    Solar envelope zoning represents a promising approach to solar access protection. A solar envelope defines the volume within which a building will not shade adjacent lots or buildings. Other solar access protection techniques, such as privately negotiated easements, continue to be tested and implemented but none offer the degree of comprehensiveness evident in this approach. Here, the City of Los Angeles, through the Mayor's Energy Office, the City Planning Department, and the City Attorney's Office, examine the feasibility of translating the concept of solar envelopes into zoning techniques. They concluded that envelope zoning is a fair and consistent method of guaranteeing solar access, but problems of complexity and uncertainty may limit its usefulness. Envelope zoning may be inappropriate for the development of high density centers and for more restrictive community plans. Aids or tools to administer envelope zoning need to be developed. Finally, some combination of approaches, including publicly recorded easements, subdivision approval and envelope zoning, need to be adopted to encourage solar use in cities. (MHR)

  12. The multi-order envelope periodic solutions to the nonlinear Schrodinger equation and cubic nonlinear Schrodinger equation

    International Nuclear Information System (INIS)

    Xiao Yafeng; Xue Haili; Zhang Hongqing

    2011-01-01

    Based on Jacobi elliptic function and the Lame equation, the perturbation method is applied to get the multi-order envelope periodic solutions of the nonlinear Schrodinger equation and cubic nonlinear Schrodinger equation. These multi-order envelope periodic solutions can degenerate into the different envelope solitary solutions. (authors)

  13. Prediction of Intelligibility of Noisy and Time-Frequency Weighted Speech based on Mutual Information Between Amplitude Envelopes

    DEFF Research Database (Denmark)

    Jensen, Jesper; Taal, C.H.

    2013-01-01

    of Shannon information the critical-band amplitude envelopes of the noisy/processed signal convey about the corresponding clean signal envelopes. The resulting intelligibility predictor turns out to be a simple function of the correlation between noisy/processed and clean amplitude envelopes. The proposed...

  14. 78 FR 31838 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection: General...

    Science.gov (United States)

    2013-05-28

    .... When failure states occur in the electronic flight control system, flight envelope protection features... any change in envelope limiting or maneuverability is produced by single or multiple failures of the...; Flight Envelope Protection: General Limiting Requirements AGENCY: Federal Aviation Administration (FAA...

  15. Data Envelopment Analysis of different climate policy scenarios

    International Nuclear Information System (INIS)

    Bosetti, Valentina; Buchner, Barbara

    2009-01-01

    Recent developments in the political, scientific and economic debate on climate change suggest that it is of critical importance to develop new approaches able to compare policy scenarios for their environmental effectiveness, their distributive effects, their enforceability, their costs and many other dimensions. This paper discusses a quantitative methodology to assess the relative performance of different climate policy scenarios when accounting for their long-term economic, social and environmental impacts. The proposed procedure is based on Data Envelopment Analysis, here employed in evaluating the relative efficiency of eleven global climate policy scenarios. The methodology provides a promising comparison framework; it can be seen as a way of setting some basic guidelines to frame further debates and negotiations and can be flexibly adopted and modified by decision makers to obtain relevant information for policy design. Three major findings emerge from this analysis: (1) stringent climate policies can outperform less ambitious proposals if all sustainability dimensions are taken into account; (2) a carefully chosen burden-sharing rule is able to bring together climate stabilisation and equity considerations; and (3) the most inefficient strategy results from the failure to negotiate a post-2012 global climate agreement. (author)

  16. Synthetic aperture radar imaging simulator for pulse envelope evaluation

    Science.gov (United States)

    Balster, Eric J.; Scarpino, Frank A.; Kordik, Andrew M.; Hill, Kerry L.

    2017-10-01

    A simulator for spotlight synthetic aperture radar (SAR) image formation is presented. The simulator produces radar returns from a virtual radar positioned at an arbitrary distance and altitude. The radar returns are produced from a source image, where the return is a weighted summation of linear frequency-modulated (LFM) pulse signals delayed by the distance of each pixel in the image to the radar. The imagery is resampled into polar format to ensure consistent range profiles to the position of the radar. The SAR simulator provides a capability enabling the objective analysis of formed SAR imagery, comparing it to an original source image. This capability allows for analysis of various SAR signal processing techniques previously determined by impulse response function (IPF) analysis. The results suggest that IPF analysis provides results that may not be directly related to formed SAR image quality. Instead, the SAR simulator uses image quality metrics, such as peak signal-to-noise ratio (PSNR) and structured similarity index (SSIM), for formed SAR image quality analysis. To showcase the capability of the SAR simulator, it is used to investigate the performance of various envelopes applied to LFM pulses. A power-raised cosine window with a power p=0.35 and roll-off factor of β=0.15 is shown to maximize the quality of the formed SAR images by improving PSNR by 0.84 dB and SSIM by 0.06 from images formed utilizing a rectangular pulse, on average.

  17. Ultraviolet extinction in M-supergiant circumstellar envelopes

    International Nuclear Information System (INIS)

    Buss, R.H. Jr.; Snow, T.P. Jr.

    1986-01-01

    Using International Ultraviolet (IUS) archival low-dispersion spectra, ultraviolet spectral extinctions were derived for the circumstellar envelopes of two M supergiants: HD 60414 and HD 213310. The observed stellar systems belong to a class of widely-separated spectroscopic binaries that are called VV Cephei stars. The total extinction was calculated by dividing the reddened fluxes with unreddened comparison fluxes of similar stars (g B2.5 for HD 213310 and a normalized s+B3 for HD 60414) from the reference atlas. After substracting the interstellar extinctions, which were estimated from the E(B-V) reddening of nearby stars, the resultant circumstellar extinctions were normalized at about 3.5 inverse microns. Not only is the 2175 A extinction bump absent in the circumstellar extinctions, but the far-ultraviolet extinction rise is also absent. The rather flat, ultraviolet extinction curves were interpreted as signatures of a population of noncarbonaceous, oxygen-rich grains with diameters larger than the longest observed wavelength

  18. Fusogenic properties of Sendai virosome envelopes in rat brain preparations.

    Science.gov (United States)

    de Fiebre, C M; Bryant, S O; Notabartolo, D; Wu, P; Meyer, E M

    1993-10-01

    Sendai virosomes were characterized with respect to their ability to bind to, fuse with, and introduce substances into several rat brain preparations. Encapsulation efficiency for Sendai virosomes was enhanced but binding to cerebral cortical P2 preparations was attenuated by addition of bovine brain phosphatidylcholine during reconstitution. A higher percentage of Sendai virosomes than phosphatidylcholine liposomes appeared to bind to, fuse with and subsequently deliver [14C]sucrose into osmotically labile pools of the P2 preparation. Fusogenic activity was estimated by measuring dequenching of fluorescently labelled N-NBD-phosphatidylethanolamine. More virosomally encapsulated [14C]sucrose was bound to the P2 fraction than introduced into osmotically labile organelles, and the fraction of vesicles undergoing fusion was intermediate between these two values. Non-encapsulated [14C]sucrose did not bind to and was not taken up by the P2 fraction in a quantifiable manner. Virosomal envelopes also bound to primary cultures of rat brain neurons and glia in an apparently saturable manner. Addition of increasing amounts of the adenoassociated virus-derived vector pJDT95 increased encapsulation efficiency, and virosomes reconstituted in the presence of 60 micrograms DNA retained most of their binding activity (5.4% of total label) compared to those containing [14C]sucrose alone (8.4%). These data indicate that Sendai virosomes may be useful in the delivery of substances into brain-derived tissues, potentially for the modulation of gene expression and neurotransmission.

  19. Coronavirus envelope (E) protein remains at the site of assembly

    International Nuclear Information System (INIS)

    Venkatagopalan, Pavithra; Daskalova, Sasha M.; Lopez, Lisa A.; Dolezal, Kelly A.; Hogue, Brenda G.

    2015-01-01

    Coronaviruses (CoVs) assemble at endoplasmic reticulum Golgi intermediate compartment (ERGIC) membranes and egress from cells in cargo vesicles. Only a few molecules of the envelope (E) protein are assembled into virions. The role of E in morphogenesis is not fully understood. The cellular localization and dynamics of mouse hepatitis CoV A59 (MHV) E protein were investigated to further understanding of its role during infection. E protein localized in the ERGIC and Golgi with the amino and carboxy termini in the lumen and cytoplasm, respectively. E protein does not traffic to the cell surface. MHV was genetically engineered with a tetracysteine tag at the carboxy end of E. Fluorescence recovery after photobleaching (FRAP) showed that E is mobile in ERGIC/Golgi membranes. Correlative light electron microscopy (CLEM) confirmed the presence of E in Golgi cisternae. The results provide strong support that E proteins carry out their function(s) at the site of budding/assembly. - Highlights: • Mouse hepatitis coronavirus (MHV-CoV) E protein localizes in the ERGIC and Golgi. • MHV-CoV E does not transport to the cell surface. • MHV-CoV can be genetically engineered with a tetracysteine tag appended to E. • First FRAP and correlative light electron microscopy of a CoV E protein. • Live-cell imaging shows that E is mobile in ERGIC/Golgi membranes

  20. Functional Analysis of Glycosylation of Zika Virus Envelope Protein.

    Science.gov (United States)

    Fontes-Garfias, Camila R; Shan, Chao; Luo, Huanle; Muruato, Antonio E; Medeiros, Daniele B A; Mays, Elizabeth; Xie, Xuping; Zou, Jing; Roundy, Christopher M; Wakamiya, Maki; Rossi, Shannan L; Wang, Tian; Weaver, Scott C; Shi, Pei-Yong

    2017-10-31

    Zika virus (ZIKV) infection causes devastating congenital abnormities and Guillain-Barré syndrome. The ZIKV envelope (E) protein is responsible for viral entry and represents a major determinant for viral pathogenesis. Like other flaviviruses, the ZIKV E protein is glycosylated at amino acid N154. To study the function of E glycosylation, we generated a recombinant N154Q ZIKV that lacks the E glycosylation and analyzed the mutant virus in mammalian and mosquito hosts. In mouse models, the mutant was attenuated, as evidenced by lower viremia, decreased weight loss, and no mortality; however, knockout of E glycosylation did not significantly affect neurovirulence. Mice immunized with the mutant virus developed a robust neutralizing antibody response and were completely protected from wild-type ZIKV challenge. In mosquitoes, the mutant virus exhibited diminished oral infectivity for the Aedes aegypti vector. Collectively, the results demonstrate that E glycosylation is critical for ZIKV infection of mammalian and mosquito hosts. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.