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1

Electrically charged compact stars  

E-print Network

We review here the classical argument used to justify the electrical neutrality of stars and show that if the pressure and density of the matter and gravitational field inside the star are large, then a charge and a strong electric field can be present. For a neutron star with high pressure (~ 10^{33} to 10^{35} dynes /cm^2) and strong gravitational field (~ 10^{14} cm/s^2), these conditions are satisfied. The hydrostatic equation which arises from general relativity, is modified considerably to meet the requirements of the inclusion of the charge. In order to see any appreciable effect on the phenomenology of the neutron stars, the charge and the electrical fields have to be huge (~ 10^{21} Volts/cm). These stars are not however stable from the viewpoint that each charged particle is unbound to the uncharged particles, and thus the system collapses one step further to a charged black hole

Subharthi Ray; Manuel Malheiro; Jose' P. S. Lemos; Vilson T. Zanchin

2006-04-17

2

Stability of polytropes  

SciTech Connect

This paper is an investigation of the stability of some ideal stars. It is intended as a study in general relativity, with emphasis on the coupling to matter, aimed at a better understanding of strong gravitational fields and 'black holes'. This contrasts with the usual attitude in astrophysics, where Einstein's equations are invoked as a refinement of classical thermodynamics and Newtonian gravity. Our work is based on action principles for systems of metric and matter fields, well-defined relativistic field models that we hope may represent plausible types of matter. The thermodynamic content must be extracted from the theory itself. When the flow of matter is irrotational, and described by a scalar density, we are led to differential equations that differ little from those of Tolman, but they admit a conserved current, and stronger boundary conditions that affect the matching of the interior solution to an external metric and imply a relation of mass and radius. We propose a complete revision of the treatment of boundary conditions. An ideal star in our terminology has spherical symmetry and an isentropic equation of state, p=a{rho}{sup {gamma}}, a and {gamma} piecewise constant. In our first work it was assumed that the density vanished beyond a finite distance from the origin and that the metric is to be matched at the boundary to an exterior Schwartzchild metric. But it is difficult to decide what the boundary conditions should be and we are consequently skeptical of the concept of a fixed boundary. We investigate the double polytrope, characterized by a polytropic index n{<=}3, in the bulk of the star and a value larger than five in an outer atmosphere that extends to infinity. It has no fixed boundary but a region of critical density where the polytropic index changes from a value that is appropriate for the bulk of the star to a value that provides a crude model for the atmosphere. The boundary conditions are now natural and unambiguous. The existence of a relation between mass and radius is confirmed, as well as an upper limit on the mass. The principal conclusion is that all the static configurations are stable. There is a solution that fits the Sun. The masses of white dwarfs respect the Chandrasekhar limit. The application to neutron stars has surprising aspects.

Froensdal, Christian [Physics Department, University of California, Los Angeles, California 90095-1547 (United States)

2008-05-15

3

Polytropic process and tropical Cyclones  

E-print Network

We show a parallelism between the expansion and compression of the atmosphere in the secondary cycle of a tropical cyclone with the fast expansion and compression of wet air in a bottle. We present a simple model in order to understand how the system (cyclone) draws energy from the air humidity. In particular we suggest that the upward (downward) expansion (compression) of the warm (cold) moist (dry) air follows a polytropic process, $PV^\\beta$= constant. We show both experimentally and analytically that $\\beta$ depends on the initial vapor pressure in the air. We propose that the adiabatic stages in the Carnot-cycle model for the tropical cyclone be replaced by two polytropic stages. These polytropic processes can explain how the wind wins energy and how the rain and the dry bands are produced inside the storm.

Romanelli, Alejandro; Rodríguez, Juan

2013-01-01

4

Conformally flat polytropes for anisotropic matter  

E-print Network

We analyze in detail conformally flat spherically symmetric fluid distributions, satisfying a polytropic equation of state. Among the two possible families of relativistic polytropes, only one contains models which satisfy all the required physical conditions. The ensuing configurations are necessarily anisotropic and show interesting physical properties. Prospective applications of the presented models to the study of super-Chandrasekhar white dwarfs, are discussed.

Herrera, L; Barreto, W; Ospino, J

2014-01-01

5

Conformally flat polytropes for anisotropic matter  

E-print Network

We analyze in detail conformally flat spherically symmetric fluid distributions, satisfying a polytropic equation of state. Among the two possible families of relativistic polytropes, only one contains models which satisfy all the required physical conditions. The ensuing configurations are necessarily anisotropic and show interesting physical properties. Prospective applications of the presented models to the study of super-Chandrasekhar white dwarfs, are discussed.

L. Herrera; A. Di Prisco; W. Barreto; J. Ospino

2014-10-24

6

Perturbation analysis of a general polytropic homologously collapsing stellar core  

NASA Astrophysics Data System (ADS)

For dynamic background models of Goldreich & Weber and Lou & Cao, we examine three-dimensional perturbation properties of oscillations and instabilities in a general polytropic homologously collapsing stellar core of a relativistically hot medium with a polytropic index ? = 4/3. Perturbation behaviours, especially internal gravity g modes, depend on the variation of specific entropy in the collapsing core. Among possible perturbations, we identify acoustic p modes and surface f modes as well as internal gravity g+ and g- modes. As in stellar oscillations of a static star, we define g+ and g- modes by the sign of the Brunt-Väisälä buoyancy frequency squared for a collapsing stellar core. A new criterion for the onset of instabilities is established for a homologous stellar core collapse. We demonstrate that the global energy criterion of Chandrasekhar is insufficient to warrant the stability of general polytropic equilibria. We confirm the acoustic p-mode stability of Goldreich & Weber, even though their p-mode eigenvalues appear in systematic errors. Unstable modes include g- modes and sufficiently high-order g+ modes, corresponding to core instabilities. Such instabilities occur before the stellar core bounce, in contrast to instabilities in other models of supernova (SN) explosions. The breakdown of spherical symmetry happens earlier than expected in numerical simulations so far. The formation and motion of the central compact object are speculated to be much affected by such g-mode instabilities. By estimates of typical parameters, unstable low-order l = 1 g-modes may produce initial kicks of the central compact object. Other high-order and high-degree unstable g modes may shred the nascent neutron core into pieces without an eventual compact remnant (e.g. SN 1987A). Formation of binary pulsars and planets around neutron stars might originate from unstable l = 2 g-modes and high-order high-degree g modes, respectively.

Cao, Yi; Lou, Yu-Qing

2009-12-01

7

Charged multiplicity measurement for simulated pp events in the Compact Muon Solenoid (CMS) detector  

E-print Network

In this thesis, I studied the effectiveness of a method for measuring the charged multiplicity of proton-proton collisions in the Compact Muon Solenoid (CMS) experiment at LHC energies ... This technique involves counting ...

Wilt, Brian A

2007-01-01

8

A Compact Wireless Charging System for Electric Vehicles  

SciTech Connect

In this paper, a compact high efficiency wireless power transfer system has been designed and developed. The detailed gate drive design, cooling system design, power stage development, and system assembling are presented. The successful tests verified the feasibility of wireless power transfer system to achieve over-all 90% efficiency.

Ning, Puqi [ORNL] [ORNL; Miller, John M [ORNL] [ORNL; Onar, Omer C [ORNL] [ORNL; White, Cliff P [ORNL] [ORNL

2013-01-01

9

Equilibrium sequences of irrotational binary polytropic stars : The case of double polytropic stars  

E-print Network

Solutions to equilibrium sequences of irrotational binary polytropic stars in Newtonian gravity are expanded in a power of $\\epsilon=a_0/R$, where R and $a_0$ are the orbital separation of the binary system and the radius of each star for $R=\\infty$. For each order of $\\epsilon$, we should solve ordinary differential equations for arbitrary polytropic indices n. We show solutions for polytropic indices n= 0.5, 1, 1.5 and 2 up to $\\epsilon^6$ orders. Our semi-analytic solutions can be used to check the validity of numerical solutions.

Keisuke Taniguchi; Takashi Nakamura

2000-04-03

10

Magnetic flux concentrations in a polytropic atmosphere  

NASA Astrophysics Data System (ADS)

Context. Strongly stratified hydromagnetic turbulence has recently been identified as a candidate for explaining the spontaneous formation of magnetic flux concentrations by the negative effective magnetic pressure instability (NEMPI). Much of this work has been done for isothermal layers, in which the density scale height is constant throughout. Aims: We now want to know whether earlier conclusions regarding the size of magnetic structures and their growth rates carry over to the case of polytropic layers, in which the scale height decreases sharply as one approaches the surface. Methods: To allow for a continuous transition from isothermal to polytropic layers, we employ a generalization of the exponential function known as the q-exponential. This implies that the top of the polytropic layer shifts with changing polytropic index such that the scale height is always the same at some reference height. We used both mean-field simulations (MFS) and direct numerical simulations (DNS) of forced stratified turbulence to determine the resulting flux concentrations in polytropic layers. Cases of both horizontal and vertical applied magnetic fields were considered. Results: Magnetic structures begin to form at a depth where the magnetic field strength is a small fraction of the local equipartition field strength with respect to the turbulent kinetic energy. Unlike the isothermal case where stronger fields can give rise to magnetic flux concentrations at larger depths, in the polytropic case the growth rate of NEMPI decreases for structures deeper down. Moreover, the structures that form higher up have a smaller horizontal scale of about four times their local depth. For vertical fields, magnetic structures of super-equipartition strengths are formed, because such fields survive downward advection that causes NEMPI with horizontal magnetic fields to reach premature nonlinear saturation by what is called the "potato-sack" effect. The horizontal cross-section of such structures found in DNS is approximately circular, which is reproduced with MFS of NEMPI using a vertical magnetic field. Conclusions: Results based on isothermal models can be applied locally to polytropic layers. For vertical fields, magnetic flux concentrations of super-equipartition strengths form, which supports suggestions that sunspot formation might be a shallow phenomenon.

Losada, I. R.; Brandenburg, A.; Kleeorin, N.; Rogachevskii, I.

2014-04-01

11

Effective geometries in self-gravitating polytropes  

SciTech Connect

Perturbations of a perfect barotropic and irrotational Newtonian self-gravitating fluid are studied using a generalization of the so-called 'effective geometry' formalism. The case of polytropic spherical stars, as described by the Lane-Emden equation, is studied in detail in the known cases of existing explicit solutions. The present formulation gives a natural scenario in which the acoustic analogy has relevance for both stellar and galactic dynamics.

Bini, D.; Cherubini, C.; Filippi, S. [Istituto per le Applicazioni del Calcolo 'M. Picone', CNR, I-00161 Rome (Italy) and International Center for Relativistic Astrophysics-I.C.R.A. University of Rome 'La Sapienza', I-00185 Rome (Italy); Nonlinear Physics and Mathematical Modeling Lab, University Campus Bio-Medico, I-00128 Rome, Italy and International Center for Relativistic Astrophysics-I.C.R.A. University of Rome 'La Sapienza', I-00185 Rome (Italy)

2008-09-15

12

Polytropic Gas Scalar Field Models of Dark Energy  

NASA Astrophysics Data System (ADS)

In this work we investigate the polytropic gas dark energy model in the non flat universe. We first calculate the evolution of EoS parameter of the model as well as the cosmological evolution of Hubble parameter in the context of polytropic gas dark energy model. Then we reconstruct the dynamics and the potential of the tachyon and K-essence scalar field models according to the evolutionary behavior of polytropic gas model.

Malekjani, M.

2013-08-01

13

Polytropic gas scalar field models of dark energy  

E-print Network

In this work we investigate the polytropic gas dark energy model in the non flat universe. We first calculate the evolution of EoS parameter of the model as well as the cosmological evolution of Hubble parameter in the context of polytropic gas dark energy model. Then we reconstruct the dynamics and the potential of the tachyon and K-essence scalar field models according to the evolutionary behavior of polytropic gas model.

Mohammad Malekjani

2012-06-04

14

On The Way To Off-equatorial Charged Discs Near Compact Objects - Single Test Particles Approximation  

NASA Astrophysics Data System (ADS)

We present our recent studies of charged particles motion out of the equatorial plane in strong gravitational and electromagnetic fields. Within the general relativistic approach, we have demonstrated that the interplay between gravitational and electromagnetic action may allow for stable off-equatorial circular motion along the so-called halo orbits near compact objects, such as rotating magnetic compact stars and Kerr black holes immersed in an asymptotically uniform magnetic field of external origin. Locations of halo orbits correspond to minima of the two-dimensional effective potential, which exhibits several qualitativelly different kinds of behaviour, reflecting the charge of moving particles and orientation of the motion. Along with the study of the halo motion itself, we have discussed the general motion in the related off-equatorial potential lobes, demonstrating its chaoticness or regularity in terms of the Poincaré surfaces of sections and recurrence plots. A possible outlook of this study is to build a single test particles model of putative circumpulsar discs consisting of charged dust particles. Institute of Physics and Astronomical Institute have been operated under the projects MSM 4781305903 and AV 0Z10030501, and further supported by the Centre for Theoretical Astrophysics LC06014 in the Czech Republic. JK, VK and ZS thank the Czech Science Foundation (ref. P209/10/P190, 205/07/0052, 202/09/0772). OK acknowledges the doctoral student program of the Czech Science Foundation (205/09/H033).

Kovar, Jiri; Kopacek, O.; Karas, V.; Stuchlik, Z.

2010-02-01

15

Polytropic bulk viscous cosmological model with variable G and ?  

E-print Network

We consider a Bianchi type-I Polytropic bulk viscous fluid cosmological model with variable G and {\\Lambda}. To get a deterministic model, we assume some conditions of A, B, C, and polytropic relation to find the results. physical significance of the cosmological models have also been discussed.

Rishi Kumar Tiwari; Mukesh Sharma; Sonia Sharma

2014-02-20

16

Universal Charge-Radius Relation for Subatomic and Astrophysical Compact Objects  

SciTech Connect

Electron-positron pair creation in supercritical electric fields limits the net charge of any static, spherical object, such as superheavy nuclei, strangelets, and Q balls, or compact stars like neutron stars, quark stars, and black holes. For radii between 4x10{sup 2} and 10{sup 4} fm the upper bound on the net charge is given by the universal relation Z=0.71R{sub fm}, and for larger radii (measured in femtometers or kilometers) Z=7x10{sup -5}R{sub fm}{sup 2}=7x10{sup 31}R{sub km}{sup 2}. For objects with nuclear density the relation corresponds to Z{approx_equal}0.7A{sup 1/3} (10{sup 8}10{sup 12}), where A is the baryon number. For some systems this universal upper bound improves existing charge limits in the literature.

Madsen, Jes [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

2008-04-18

17

General polytropic Larson-Penston-type collapses  

NASA Astrophysics Data System (ADS)

We investigate self-similar hydrodynamics of a general polytropic (GP) gas with spherical symmetry under self-gravity and extend the conventional polytropic (CP) relation n = 2 - ? for the self-similar index n and the polytropic index ? to a general relation n = 2(q + ? - 2)/(3q - 2), where q is a real parameter by specific entropy conservation along streamlines. We derive GP Larson-Penston (LP)-type solutions for q > 2/3 and ? > 4/3; Larson-Penston-Hunter (LPH)-type solutions are also constructed in a GP gas by a time-reversal operation on a GP-LP-type solution and by connecting to a GP free-fall-type solution across t = 0. These GP-LPH solutions describe dynamic processes that a GP gas globule, static and dense initially, undergoes a runaway collapse under self-gravity, forms a central mass singularity, and keeps accreting during a free-fall stage. We apply such GP-LPH-type solutions with variable envelope mass infall rates (EMIRs) for the dynamic evolution of globules and dense cores in star-forming molecular clouds. In particular, a GP-LPH-type solution can sustain an EMIR as low as 10-8 ˜ 10-6 M? yr-1 or even lower - much lower than that of Shu's isothermal model for a cloud core in Class 0 and Class I phases. Such GP-LPH-type solutions with EMIRs as low as 10-9 ˜ 10-8 M? yr-1 offer a sensible viable mechanism of forming brown dwarfs during the accretion stage in a collapsed GP globules with 1.495 ? ? ? 1.50 and 0.99 ? n ? 1.0. The GP-LPH solutions with 0.94 < n < 0.99 and 1.47 < ? < 1.495 can even give extremely low EMIRs of 10-12 ˜ 10-9 M? yr-1 to form gaseous planet-type objects in mini gas globules.

Lou, Yu-Qing; Shi, Chun-Hui

2014-12-01

18

Fast-charging compact seed source for magnetic flux compression generators  

NASA Astrophysics Data System (ADS)

Flux compression generators (FCGs) are some of the most attractive sources of single-use compact pulsed power available today due to their high energy density output and mobility. Driving FCGs requires some seed energy, which is typically provided by applying a high seed current, usually in the kiloampere range for midsized helical FCGs. This initial current is supplied by a high-current seed source that is capable of driving an inductive load. High-current seed sources have typically been comprised of discharging large capacitors using spark gaps and overvoltage triggering mechanisms to provide the prime power for FCGs. This paper will discuss a recent design of a self-contained (battery powered with full charge time less than 40 s), single-use compact seed source (CSS) using solid-state components for the switching scheme. The CSS developed is a system (0.005 m3 volume and weighing 3.9 kg) capable of delivering over 360 J (˜12 kA) into a 5.20 ?H load with a trigger energy of microjoules at the TTL triggering level. The newly designed solid-state switching scheme of the CSS incorporates off-the-shelf high-voltage semiconductor components that minimize system cost and size as necessary for a single-use application. A detailed evaluation of the CSS is presented primarily focusing on the switching mechanics and experimental characterization of the solid-state components used in the system.

Elsayed, M.; Kristiansen, M.; Neuber, A.

2008-12-01

19

Illustration of the linear-muffin-tin-orbital tight-binding representation: Compact orbitals and charge density in Si  

Microsoft Academic Search

Plots of the tight-binding (TB) orbitals recently derived by exact transformation of the conventional set of linear muffin-tin orbitals (LMTO's) are presented for crystalline silicon. The TB-LMTO's are found to be extremely compact. As a simple application we show how non-spherically-averaged charge densities may be obtained from standard LMTO calculations. For silicon this charge density is found to be in

O. K. Andersen; Z. Pawlowska; O. Jepsen

1986-01-01

20

The thickness of the magnetosheath: Constraints on the polytropic index  

Microsoft Academic Search

A statistical analysis of 351 independent bow shock crossings and 233 independent magnetopause crossings by the ISEE-1 spacecraft from 1977 to 1980 was performed to determine the average positions and shapes of the bow shock and magnetopause. The standoff distance between the magnetopause and the bow shock depends on the compressibility of the plasma which in the polytropic' approximation is

M. H. Farris; S. M. Petrinec; C.T. Russell

1991-01-01

21

Numerical Modeling of Tidal Effects in Polytropic Accretion Discs  

NASA Technical Reports Server (NTRS)

A two-dimensional time-dependent hybrid Fourier-Chebyshev method of collocation is developed and used for the study of tidal effects in accretion discs, under the assumption of a polytropic equation of state and a standard alpha viscosity prescription.

Godon, P.

1996-01-01

22

The Study of Two-dimensional Polytropic Stars  

E-print Network

In this article we have studied the structure of hypothetical two-dimensional polytropic stars. Considering some academic interest, we have developed a formalism to investigate some of the gross properties of such stellar objects. However, we strongly believe that the formalism developed here may be prescribed as class problem for post-graduate level students in physics or a post-graduate dissertation project work in physics.

Sanchari De; Somenath Chakrabarty

2014-04-28

23

Gravitational instability of polytropic spheres and generalized thermodynamics  

NASA Astrophysics Data System (ADS)

We extend the existing literature on the structure and stability of polytropic gas spheres reported in the classical monograph of Chandrasekhar (\\cite{chandra}). For isolated polytropes with index 1polytropes confined within a box of radius R (an extension of the Antonov problem for isothermal gas spheres). For n>=3, the mass-density relation presents damped oscillations and there exists a limiting mass above which no hydrostatic equilibrium is possible. As for isothermal gas spheres, the onset of instability occurs precisely at the point of maximum mass in the series of equilibrium. Analytical results are obtained for the particular index n=5. We also discuss the relation of our study with generalized thermodynamics (Tsallis entropy) recently investigated by Taruya & Sakagami (\\cite{taruya}).

Chavanis, P. H.

2002-05-01

24

Near-polytropic stellar simulations with a radiative surface  

NASA Astrophysics Data System (ADS)

Context. Studies of solar and stellar convection often employ simple polytropic setups using the diffusion approximation instead of solving the proper radiative transfer equation. This allows one to control separately the polytropic index of the hydrostatic reference solution, the temperature contrast between top and bottom, and the Rayleigh and Péclet numbers. Aims: Here we extend such studies by including radiative transfer in the gray approximation using a Kramers-like opacity with freely adjustable coefficients. We study the properties of such models and compare them with results from the diffusion approximation. Methods: We use the Pencil code, which is a high-order finite difference code where radiation is treated using the method of long characteristics. The source function is given by the Planck function. The opacity is written as ? = ?0?aTb, where a = 1 in most cases, b is varied from -3.5 to + 5, and ?0 is varied by four orders of magnitude. We adopt a perfect monatomic gas. We consider sets of one-dimensional models and perform a comparison with the diffusion approximation in one- and two-dimensional models. Results: Except for the case where b = 5, we find one-dimensional hydrostatic equilibria with a nearly polytropic stratification and a polytropic index close to n = (3 - b)/(1 + a), covering both convectively stable (n> 3/2) and unstable (n< 3/2) cases. For b = 3 and a = -1, the value of n is undefined a priori and the actual value of n depends then on the depth of the domain. For large values of ?0, the thermal adjustment time becomes long, the Péclet and Rayleigh numbers become large, and the temperature contrast increases and is thus no longer an independent input parameter, unless the Stefan-Boltzmann constant is considered adjustable. Conclusions: Proper radiative transfer with Kramers-like opacities provides a useful tool for studying stratified layers with a radiative surface in ways that are more physical than what is possible with polytropic models using the diffusion approximation. Appendices are available in electronic form at http://www.aanda.org

Barekat, A.; Brandenburg, A.

2014-11-01

25

Caloric curves fitted by polytropic distributions in the HMF model  

NASA Astrophysics Data System (ADS)

We perform direct numerical simulations of the Hamiltonian mean field (HMF) model starting from non-magnetized initial conditions with a velocity distribution that is (i) Gaussian; (ii) semi-elliptical, and (iii) waterbag. Below a critical energy E c , depending on the initial condition, this distribution is Vlasov dynamically unstable. The system undergoes a process of violent relaxation and quickly reaches a quasi-stationary state (QSS). We find that the distribution function of this QSS can be conveniently fitted by a polytrope with index (i) n = 2; (ii) n = 1; and (iii) n = 1/2. Using the values of these indices, we are able to determine the physical caloric curve T kin ( E) and explain the negative kinetic specific heat region C kin = dE/ d T kin < 0 observed in the numerical simulations. At low energies, we find that the system has a "core-halo" structure. The core corresponds to the pure polytrope discussed above but it is now surrounded by a halo of particles. In case (iii), we recover the "uniform" core-halo structure previously found by Pakter and Levin [Phys. Rev. Lett. 106, 200603 (2011)]. We also consider unsteady initial conditions with magnetization M 0 = 1 and isotropic waterbag velocity distribution and report the complex dynamics of the system creating phase space holes and dense filaments. We show that the kinetic caloric curve is approximately constant, corresponding to a polytrope with index n 0 ? 3.56 (we also mention the presence of an unexpected hump). Finally, we consider the collisional evolution of an initially Vlasov stable distribution, and show that the time-evolving distribution function f( ?,v,t) can be fitted by a sequence of polytropic distributions with a time-dependent index n( t) both in the non-magnetized and magnetized regimes. These numerical results show that polytropic distributions (also called Tsallis distributions) provide in many cases a good fit of the QSSs. They may even be the rule rather than the exception. However, in order to moderate our message, we also report a case where the Lynden-Bell theory (which assumes ergodicity or efficient mixing) provides an excellent prediction of an inhomogeneous QSS. We therefore conclude that both Lynden-Bell and Tsallis distributions may be useful to describe QSSs depending on the efficiency of mixing.

Campa, Alessandro; Chavanis, Pierre-Henri

2013-04-01

26

Can rigidly rotating polytropes be sources of the Kerr metric?  

E-print Network

We use a recent result by Cabezas et al. to build up an approximate solution to the gravitational field created by a rigidly rotating polytrope. We solve the linearized Einstein equations inside and outside the surface of zero pressure including second-order corrections due to rotational motion to get an asymptotically flat metric in a global harmonic coordinate system. We prove that if the metric and their first derivatives are continuous on the matching surface up to this order of approximation, the multipole moments of this metric cannot be fitted to those of the Kerr metric.

J. Martin; A. Molina; E. Ruiz

2007-09-07

27

Superfluid hydrodynamics of polytropic gases: dimensional reduction and sound velocity  

NASA Astrophysics Data System (ADS)

Motivated by the fact that two-component confined fermionic gases in Bardeen-Cooper-Schrieffer-Bose-Einstein condensate (BCS-BEC) crossover can be described through an hydrodynamical approach, we study these systems—both in the cigar-shaped configuration and in the disc-shaped one—by using a polytropic Lagrangian density. We start from the Popov Lagrangian density and obtain, after a dimensional reduction process, the equations that control the dynamics of such systems. By solving these equations we study the sound velocity as a function of the density by analyzing how the dimensionality affects this velocity.

Bellomo, N.; Mazzarella, G.; Salasnich, L.

2014-03-01

28

Cosmological Implications of Interacting Polytropic Gas Dark Energy Model in Non-flat Universe  

NASA Astrophysics Data System (ADS)

The polytropic gas model is investigated as an interacting dark energy scenario. The cosmological implications of the model including the evolution of EoS parameter w ?, energy density ?? and deceleration parameter q are investigated. We show that, depending on the parameter of model, the interacting polytropic gas can behave as a quintessence or phantom dark energy. In this model, the phantom divide is crossed from below to up. The evolution of q in the context of polytropic gas dark energy model represents the decelerated phase at the early time and accelerated phase later. The singularity of this model is also discussed. Eventually, we establish the correspondence between interacting polytropic gas model with tachyon, K-essence and dilaton scalar fields. The potential and the dynamics of these scalar field models are reconstructed according to the evolution of interacting polytropic gas.

Malekjani, M.; Khodam-Mohammadi, A.; Taji, M.

2011-10-01

29

POLYTROPIC MODEL FITS TO THE GLOBULAR CLUSTER NGC 2419 IN MODIFIED NEWTONIAN DYNAMICS  

SciTech Connect

We present an analysis of the globular cluster NGC 2419, using a polytropic model in modified Newtonian dynamics (MOND) to reproduce recently published high-quality data on the structure and kinematics of the system. We show that a specific MOND polytropic model of NGC 2419 suggested by a previous study can be completely ruled out by the data. Furthermore, the highest likelihood fit polytrope in MOND is a substantially worse model (by a factor of {approx}5000) than a Newtonian Michie model we studied previously. We conclude that the structure and dynamics of NGC 2419 favor Newtonian dynamics and do indeed challenge the MOND theory.

Ibata, R. [Observatoire Astronomique, Universite de Strasbourg, CNRS, 11 rue de l'Universite, F-67000 Strasbourg (France); Sollima, A. [INAF-Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, I-35122 Padova (Italy); Nipoti, C.; Dalessandro, E. [Dipartimento di Astronomia, Universita degli Studi di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Bellazzini, M. [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Chapman, S. C., E-mail: rodrigo.ibata@astro.unistra.fr [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)

2011-12-10

30

Ellipsoidal figures of equilibrium - Compressible models. [for self-gravitating Newtonian fluids in rotating polytropes  

NASA Technical Reports Server (NTRS)

The results of Chandrasekhar (1969) are generalized to polytropes, using a formalism based on ellipsoidal energy variational principle to construct approximate stellar equilibrium solutions and study their stability. After reviewing the energy variational method and describing the approach, several equivalent stability conditions are established and secular vs. dynamical instabilities are discussed. Then, the equilibrium structure equations are derived for isolated, rotating polytropes, and axisymmetric configurations (compressible Maclaurin spheroids) are considered. Particular attention is given to triaxial configurations, either in a state of uniform rotation (generalizing the classical Jacobi ellipsoids) or with internal fluid motions of uniform vorticity (the compressible analogues of Riemann-S ellipsoids) and to the stability of these single star configurations. The compressible generalizations of the Roche and Roche-Riemann problems for a polytrope in orbit about a point-mass companion are solved, and the generalized Darwin problem for two identical polytropes in a binary is considered.

Lai, Dong; Rasio, Frederic A.; Shapiro, Stuart L.

1993-01-01

31

Cosmological Implications of Interacting Polytropic Gas Dark Energy Model in Non-flat Universe  

Microsoft Academic Search

The polytropic gas model is investigated as an interacting dark energy scenario. The cosmological implications of the model\\u000a including the evolution of EoS parameter w\\u000a ?, energy density ?? and deceleration parameter q are investigated. We show that, depending on the parameter of model, the interacting polytropic gas can behave as a quintessence\\u000a or phantom dark energy. In this model,

M. Malekjani; A. Khodam-Mohammadi; M. Taji

2011-01-01

32

Interacting polytropic gas model of dark energy in non-flat universe  

Microsoft Academic Search

The polytropic gas model is investigated as an interacting dark energy\\u000ascenario. In this model the evolution of cosmological parameters such as the\\u000aEoS parameter $w_{\\\\Lambda}$, energy density $\\\\Omega_{\\\\Lambda}$ and deceleration\\u000aparameter $q$ are investigated. These parameters are dependent on the\\u000aparameters of the model. We show that, depending on the parameter of model, the\\u000ainteracting polytropic gas can behave

M. Malekjani; A. Khodam-Mohammadi; M. Taji

2010-01-01

33

Numerical Modeling of Tidal Effects in Polytropic Accretion Disks  

NASA Technical Reports Server (NTRS)

A two-dimensional time-dependent hybrid Fourier-Chebyshev method of collocation is developed and used for the study of tidal effects in accretion disks, under the assumptions of a polytropic equation of state and a standard alpha viscosity prescription. Under the influence of the m = 1 azimuthal component of the tidal potential, viscous oscillations in the outer disk excite an m = 1 eccentric instability in the disk. While the m = 2 azimuthal component of the tidal potential excites a Papaloizou-Pringle instability in the inner disk (a saturated m = 2 azimuthal mode), with an elliptic pattern rotating at about a fraction (approx. = 1/3) of the local Keplerian velocity in the inner disk. The period of the elliptic mode corresponds well to the periods of the short-period oscillations observed in cataclysmic variables. In cold disks (r(Omega)/c(sub s) = M approx. = 40) we also find a critical value of the viscosity parameter (alpha approx. = 0.01), below which shock dissipation dominates and is balanced by the wave amplification due to the wave action conservation. In this case the double spiral shock propagates all the way to the inner boundary with a Mach number M(sub s) approx. = 1.3.

Godon, Patrick

1997-01-01

34

The Polytrope Index Revealed: Implications for Planet, Solar and Material Models  

E-print Network

Techniques to model the interior of planets are varied. We introduce a new approach to a century old assumption which enhances not only planetary interior calculations but also solar models and high pressure material physics. Our methodology uses the polytrope assumption which was used to model main sequence and white dwarf stars by Eddington. A polytrope is a simple structural assumption between a material's pressure and volume, $PV^n = C$, where $C$ is a constant and $n$ is the polytrope index. We derive that the polytropic index is the derivative of the bulk modulus with respect to pressure. We then augment the theory by including a variable polytrope index which produces a high quality universal equation of state, within the confines of the Lane-Emden differential equation, making it a robust tool with the potential for excellent predictive power. Unlike most previous equations of state, which have pressure as the dependent variable, the theoretical foundation of our equation of state is the same elastic ...

Weppner, S P; Thielen, K D; Zielinski, A K

2014-01-01

35

Compact Analytic Expression for the Electric Field of a 2DElliptical Charge Distribution Inside a Perfectly Conducting CircularCylinder  

SciTech Connect

By combining the method of images with calculus of complex variables, we provide a simple expression for the electric field of a two-dimensional (2D) static elliptical charge distribution inside a perfectly conducting cylinder. The charge distribution need not be concentric with the cylinder.

Furman, M.A.

2007-05-29

36

Almost analytic solutions to equilibrium sequences of irrotational binary polytropic stars for n=1  

E-print Network

A solution to an equilibrium of irrotational binary polytropic stars in Newtonian gravity is expanded in a power of \\epsilon=a_0/R, where R and a_0 are the separation of the binary system and the radius of each star for R=\\infty. For the polytropic index n=1, the solutions are given almost analytically up to order \\epsilon^6. We have found that in general an equilibrium solution should have the velocity component along the orbital axis and that the central density should decrease when R decreases. Our almost analytic solutions can be used to check the validity of numerical solutions.

Keisuke Taniguchi; Takashi Nakamura

1999-11-23

37

Polytropic gas spheres: An approximate analytic solution of the Lane-Emden equation  

E-print Network

Polytropic models play a very important role in galactic dynamics and in the theory of stellar structure and evolution. However, in general, the solution of the Lane-Emden equation can not be given analytically but only numerically. In the Lane-Emden equation can not be given analytically but only numerically. In this paper we give a very good and simple analytic approximate solution of the Lane-Emden equation. This approximation is very good for any finite polytropic index $n$ and for the isothermal case (n equals infinity) at a level $<1\\%$. We also give analytic expressions of the mass, pressure, temperature, and potential energy as a function of radius.

F. K. Liu

1995-12-11

38

Compact accelerator  

DOEpatents

A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

Caporaso, George J. (Livermore, CA); Sampayan, Stephen E. (Manteca, CA); Kirbie, Hugh C. (Los Alamos, NM)

2007-02-06

39

Local pellet based and line-integrated nonperturbing charge exchange measurements with a compact neutral particle analyzer on Large Helical Device  

NASA Astrophysics Data System (ADS)

Experiments on suprathermal ion physics are carried out on the Large Helical Device (LHD) with a 40 channel compact neutral particle analyzer (CNPA). The analyzer is used both in passive nonperturbing chord-integral neutral particle flux measurements and for local probing with an impurity pellet. The analyzer observes trapped particles with ?v?/v?<0.25 and the pitch angle cosine value v?/v changes sign along the diagnostic sight line. The measurable energy range for H0 is 1-170keV. Radially resolved data on local H0 atomic energy spectra have been obtained on LHD by the pellet charge exchange method with CNPA, as well as chord-integral atomic energy distribution data for electron cyclotron heated, neutral beam injected, and high power ion cyclotron heated plasma. The article addresses the diagnostic technical background and the analysis scheme of measurement results taking into account the helical geometry and the species and densities of the charge exchange targets.

Goncharov, P. R.; Ozaki, T.; Sudo, S.; Tamura, N.; Tespel Group, Lhd Experimental Group, Veshchev, E. A.; Sergeev, V. Yu.; Krasilnikov, A. V.

2006-10-01

40

Performance of a compact position-sensitive photon counting detector with image charge coupling to an air-side anode  

NASA Astrophysics Data System (ADS)

We discuss a novel micro-channel plate (MCP) photomultiplier with resistive screen (RS-PMT) as a detection device for space- and time-correlated single photon counting, illustrated by several applications. The photomultiplier tube resembles a standard image intensifier device. However, the rear phosphor screen is replaced by a ceramic "window" with resistive coating. The MCP output is transferred through the ceramic plate to the read-out electrode (on the air side) via capacity-coupling of the image charge. This design allows for an easy reconfiguration of the read-out electrode (e.g. pixel, charge-sharing, cross-strip, delay-line) without breaking the vacuum for optimizing the detector performance towards a certain task. It also eases the design and manufacturing process of such a multi-purpose photomultiplier tube. Temporal and spatial resolutions well below 100 ps and 100 microns, respectively, have been reported at event rates as high as 1 MHz, for up to 40 mm effective detection diameter. In this paper we will discuss several applications like wide-field fluorescence microscopy and dual ?/fast-neutron radiography for air cargo screening and conclude with an outlook on large-area detectors for thermal neutrons based on MCPs.

Jagutzki, O.; Czasch, A.; Schössler, S.

2013-05-01

41

Effective geometry of the n=1 uniformly rotating self-gravitating polytrope  

SciTech Connect

The ''effective geometry'' formalism is used to study the perturbations of a perfect barotropic Newtonian self-gravitating rotating and compressible fluid coupled with gravitational backreaction. The case of a uniformly rotating polytrope with index n=1 is investigated, due to its analytical tractability. Special attention is devoted to the geometrical properties of the underlying background acoustic metric, focusing, in particular, on null geodesics as well as on the analog light cone structure.

Bini, D.; Cherubini, C.; Filippi, S.; Geralico, A. [Istituto per le Applicazioni del Calcolo 'M. Picone', CNR, I-00185 Rome (Italy) and ICRA, University of Rome 'La Sapienza', I-00185 Rome (Italy); Nonlinear Physics and Mathematical Modeling Lab, Engineering Faculty, University Campus Bio-Medico, I-00128 Rome (Italy) and ICRA, University of Rome 'La Sapienza', I-00185 Rome (Italy); Physics Department and ICRA, University of Rome 'La Sapienza', I-00185 Rome (Italy)

2010-08-15

42

Closure of the hierarchy of fluid equations by means of the polytropic-coefficient function (PCF)  

SciTech Connect

The continuity and momentum equations of a fluid plasma component may be viewed as four scalar evolution equations for the four scalar fluid variables n(x-vector,t)(density) and u(x-vector,t)(fluid velocity), which are zeroth- and first order velocity moments of the velocity distribution function (VDF). However, the momentum equation in addition contains the gradient of the pressure p(x-vector,t), which is a second-order velocity moment for which another equation, the 'closure equation', is needed. In the present work, closure by means of the polytropic-coefficient function (PCF) is discussed which, by analogy with the well-known polytropic coefficient (also called the 'polytropic index' or 'polytropic exponent') in macroscopic thermodynamic systems, is formally defined by {gamma}(x-vector,t) = (nDp/Dt)(pDn/Dt) = (n/p)(Dp/Dn), with D/Dt = {partial_derivative}/{partial_derivative}t+u-vector{center_dot}{partial_derivative}/{partial_derivative}x-vector, which amounts to the closure equation if {gamma}(x-vector,t) is known. In fluid problems, however, the PCF is usually unknown and hence must be assumed or guessed, but in kinetic problems it can be calculated exactly. These general concepts are first developed and then applied specifically to the basic Tonks-Langmuir (TL) model [L. Tonks and I. Langmuir, Phys. Rev. 34, 876, 1929]. It is shown for the first time that results obtained from the fluid equations closed with the correct PCF coincide with the corresponding results calculated on the basis of the exact kinetic solution [K.-U. Riemann, Phys. Plasmas 13, 063508 (2006)], but differ visibly from those obtained from the approximate fluid equations closed with the zero-pressure approximation [Riemann et al., Plasma Phys. Control. Fusion 47, 1949 (2005)]. Also, it is again confirmed that the correct PCF may be a strongly varying function of position, so that the simple constant values of {gamma} usually assumed [K.-U. Riemann, XXVIII International Conference on Phenomena in Ionized Gases, 479 (2007)] may lead to markedly erroneous results especially near material walls. All of these findings lead us to conclude that better approximations to the PCF are needed for closing fluid equations in an appropriate manner.

Kuhn, S.; Kamran, M.; Jelic, N. [Association EURATOM-OAeW, Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria); Kos, L. [LECAD Laboratory, University of Ljubljana, SI-1000 Ljubljana (Slovenia); Tskhakaya, D. jr; Tskhakaya, D. D. sr [Association EURATOM-OAeW, Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria); Andronikashvili Institute of Physics, Georgian Academy of Sciences, Tbilisi 0177 (Georgia)

2010-12-14

43

Superfluid hydrodynamics of polytropic gases:dimensional reduction and sound velocity  

E-print Network

Motivated by the fact that two-component confined fermionic gases in Bardeen-Cooper-Schrieffer-Bose-Einstein condensate (BCS-BEC) crossover can be described through an hydrodynamical approach, we study these systems - both in the cigar-shaped configuration and in the disk-shaped one - by using a polytropic Lagrangian density. We start from the Popov Lagrangian density and obtain, after a dimensional reduction process, the equations that control the dynamics of such systems. By solving these equations we study the sound velocity as a function of the density by analyzing how the dimensionality affects this velocity

Nicola Bellomo; Giovanni Mazzarella; Luca Salasnich

2014-01-21

44

Initial data for high-compactness black hole-neutron star binaries  

E-print Network

For highly compact neutron stars, constructing numerical initial data for black hole-neutron star binary evolutions is very difficult. We describe improvements to an earlier method that enable it to handle these more challenging cases. We examine the case of a 6:1 mass ratio system in inspiral close to merger, where the star is governed by a polytropic $\\Gamma=2$, an SLy, or an LS220 equation of state. In particular, we are able to obtain a solution with a realistic LS220 equation of state for a star with compactness 0.26 and mass 1.98 $M_\\odot$, which is representative of the highest reliably determined neutron star masses. For the SLy equation of state, we can obtain solutions with a comparable compactness of 0.25, while for a family of polytropic equations of state, we obtain solutions with compactness up to 0.21, the largest compactness that is stable in this family. These compactness values are significantly higher than any previously published results. We find that improvements in adapting the computational domain to the neutron star surface and in accounting for the center of mass drift of the system are the key ingredients allowing us to obtain these solutions.

Katherine Henriksson; François Foucart; Lawrence E. Kidder; Saul A. Teukolsky

2014-09-25

45

Self-gravitating rotating anisotropic pressure plasma in presence of Hall current and electrical resistivity using generalized polytrope laws  

SciTech Connect

The effects of uniform rotation, finite electrical resistivity, electron inertia, and Hall current on the self-gravitational instability of anisotropic pressure plasma with generalized polytrope laws have been studied. A general dispersion relation is obtained with the help of the relevant linearized perturbed magnetohydrodynamic (MHD) equations incorporating the relevant contributions of various effects of the problem using the method of normal mode analysis. The general dispersion relation is further reduced for the special cases of rotation; i.e., parallel and perpendicular to the direction of the magnetic field. The longitudinal and transverse modes of propagation are discussed separately for investigation of condition of instability. The effects of rotation, Hall current, finite electron inertia, and polytropic indices are discussed on the gravitational, ''firehose,'' and ''mirror'' instabilities. The numerical calculations have been performed to obtain the dependence of the growth rate of the gravitational unstable mode on the various physical parameters involved. The finite electrical resistivity, rotation, and Hall current have a stabilizing influence on the growth rate of the unstable mode of wave propagation. The finite electrical resistivity removes the effect of magnetic field and polytropic index from the condition of instability in the transverse mode of propagation for both the cases of rotation. It is also found that the Jeans criterion of gravitational instability depends upon rotation, electron inertia, and polytropic indices. In the case of transverse mode of propagation with the axis of rotation parallel to the magnetic field, it is observed that the region of instability and the value of the critical Jeans wavenumber are larger for the Chew-Goldberger-Low set of equations in comparison with the MHD set of equations. The stability of the system is discussed by applying Routh-Hurwitz criterion. The inclusion of rotation or Hall current or both together depresses the growth rate of mirror instability. We also note that the condition of mirror instability depends upon polytropic indices.

Prajapati, R. P.; Chhajlani, R. K. [School of Studies in Physics, Vikram University, Ujjain-456010 (M.P.) (India); Soni, G. D. [Government Girls Degree College, Dewas, (M.P.) (India)

2008-06-15

46

Relativistic self-similar dynamic collapses of black holes in general polytropic spherical clouds  

NASA Astrophysics Data System (ADS)

We study the hydrodynamic self-similar mass collapses of general polytropic (GP) spherical clouds to central Schwarzschild black holes and void evolution with or without shocks. In order to grossly capture characteristic effects of general relativity outside yet close to the event horizon of a Schwarzschild black hole and to avoid mathematical complexity, we adopt the approximation of the Paczynski-Wiita gravity to replace the simple Newtonian gravity in our model formulation. A new dimensionless parameter s appears with the physical meaning of the square of the ratio of the sound speed to the speed of light c. Various self-similar dynamic solutions are constructed for a polytropic index ? > 4/3. Two (for small enough s < 1) or no (for large enough s < 1) expansion-wave collapse solutions with central event horizons exist when ? > 4/3, representing the collapse of static singular GP spheres towards the central singularity of space-time. Such GP spherical dynamic mass collapse is shown to be highly efficient for the rapid formation of supermassive black holes (mass range of ˜106-1010 M?) in the early Universe or even hypermassive black holes (mass range of ˜1010-1012 M?) if extremely massive mass reservoirs could be sustained for a sufficiently long time, which may evolve into hard X-ray/gamma-ray sources or quasars according to their surroundings. Self-similar dynamic solutions of a GP gas are also proposed for the stellar mass black hole formation during the violent supernova explosion of a massive progenitor star, the time-scale of which is estimated of ˜10-3 s. Rebound shocks travelling in supernovae are also discussed based on our self-similar shock expansion solutions.

Lian, Biao; Lou, Yu-Qing

2014-02-01

47

Hydrodynamics of binary coalescence. 2: Polytropes with gamma = 5/3  

NASA Technical Reports Server (NTRS)

We present a new numerical study of the equilibrium and stability properties of close binary systems. We use the smoothed-particle hydrodynamics (SPH) technique both to construct accurate equilibrium configurations in three dimensions and to follow their hydrodynamic evolution. We adopt a simple polytropic equation of state p = K(sub rho)(exp gamma) with gamma = 5/3 and K = constant within each star, applicable to low-mass degenerate dwarfs as well as low-mass main-sequence stars. For degenerate configurations, we set the two polytropic constants equal, K = K prime, independent of the mass ratio. For main-sequence stars, we adjust K and K prime so as to obtain a simple mass-radius relation of the form R/R prime = M/M prime, where R prime and M prime are the radius and mass of the secondary. Along a sequence of binary equilibrium configurations for two identical stars, we demonstrate the existence of both secular and dynamical instabilities, confirming directly the results of recent analytic work. We use the SPH method to calculate the nonlinear development of the dynamical instability and to determine the final fate of the system. We find that the two stars merge together into a single, rapidly rotating object in just a few orbital periods. Equilibrium sequences are also constructed for systems containing two nonidentical stars. These sequences terminate at a Roche limit, which we can determine very accurately using SPH. For two low-mass main-sequence stars with mass ratio q approximately less than 0.4 we find that the (synchronized) Roche limit configuration is secularly unstable. We discuss the implications of our results for the evolution of double white-dwarf systems and W Ursae Majoris binaries.

Rasio, Frederic A.; Shapiro, Stuart L.

1995-01-01

48

Charged Condensation  

E-print Network

We consider Bose-Einstein condensation of massive electrically charged scalars in a uniform background of charged fermions. We focus on the case when the scalar condensate screens the background charge, while the net charge of the system resides on its boundary surface. A distinctive signature of this substance is that the photon acquires a Lorentz-violating mass in the bulk of the condensate. Due to this mass, the transverse and longitudinal gauge modes propagate with different group velocities. We give qualitative arguments that at high enough densities and low temperatures a charged system of electrons and helium-4 nuclei, if held together by laboratory devices or by force of gravity, can form such a substance. We briefly discuss possible manifestations of the charged condensate in compact astrophysical objects.

Gregory Gabadadze; Rachel A. Rosen

2007-06-15

49

Effect of pressure anisotropy and flow velocity on Kelvin-Helmholtz instability of anisotropic magnetized plasma using generalized polytrope laws  

SciTech Connect

The effect of pressure anisotropy and flow velocity on the Kelvin-Helmholtz (KH) instability of two magnetized anisotropic pressure plasmas flowing relative to each other is investigated using generalized polytrope laws. The anisotropic pressure with the generalized polytrope laws is considered with three-dimensional perturbations in the description of plasma using relevant magnetohydrodynamic (MHD) set of equations. The magnetic field is assumed in the x-direction and parallel to the direction of the flow of plasma streams. A complete polytrope model is given for the considered system in terms of pressure components, magnetic field, and density of the fluids to discuss the condition of KH instability, stability, and overstability. The problem is solved using the normal mode analysis and the general dispersion relation is obtained by applying the appropriate boundary conditions. The case of nonvanishing wavenumber transverse to the direction of the stream is obtained, which represents the stationery configuration without excitation of KH instability. The longitudinal mode of propagation is discussed with conditions of KH instability, stability, and overstability for collisionless (anisotropic) double-adiabatic Chew-Goldberger-Low (CGL) and collisional (isotropic) MHD media, depending on various values of polytrope indices. The effects of pressure anisotropy, different flow velocities, and magnetic field are also discussed on the growth rate of KH instability. We observe that the presence of flow velocity and pressure anisotropy of the plasmas has a destabilizing influence on the growth rate of the system. The growth rate is found larger for MHD set of equations in comparison to the CGL set of equations. The presence of magnetic field has a stabilizing role on the growth rate of the considered system.

Prajapati, R. P.; Chhajlani, R. K. [School of Studies in Physics, Vikram University, Ujjain, Madhya Pradesh 456010 (India)

2010-11-15

50

Receptor choice determinants in the envelope glycoproteins of amphotropic, xenotropic, and polytropic murine leukemia viruses.  

PubMed Central

The envelope glycoproteins (SU) of mammalian type C retroviruses possess an amino-terminal domain of about 200 residues, which is involved in binding a cell surface receptor. In this domain, highly conserved amino acid sequences are interrupted by two segments of variable length and sequence, VRA and VRB. We have studied the role of these variable regions in receptor recognition and binding by constructing chimeric molecules in which portions of the amino-terminal domains from amphotropic (4070A), xenotropic (NZB), and polytropic (MCF 247) murine leukemia virus SU proteins were permuted. These chimeras, which exchanged either one or two variable regions, were expressed at the surface of replication-defective viral particles by a pseudotyping assay. Wild-type or recombinant env genes were transfected into a cell line producing Moloney murine leukemia virus particles devoid of envelope glycoproteins in which a retrovirus vector genome carrying an Escherichia coli lacZ gene was packaged. The host range and sensitivity to interference of pseudotyped virions were assayed, and we observed which permutations resulted in receptor switch or loss of function. Our results indicate that the determinants of receptor choice are found within the just 120 amino acids of SU proteins. Downstream sequences contribute to the stabilization of the receptor-specific structure. PMID:1310758

Battini, J L; Heard, J M; Danos, O

1992-01-01

51

Gravitational Instability of Rotating, Pressure-confined, Polytropic Gas Disks with Vertical Stratification  

NASA Astrophysics Data System (ADS)

We investigate the gravitational instability (GI) of rotating, vertically stratified, pressure-confined, polytropic gas disks using a linear stability analysis as well as analytic approximations. The disks are initially in vertical hydrostatic equilibrium and bounded by a constant external pressure. We find that the GI of a pressure-confined disk is in general a mixed mode of the conventional Jeans and distortional instabilities, and is thus an unstable version of acoustic-surface-gravity waves. The Jeans mode dominates in weakly confined disks or disks with rigid boundaries. On the other hand, when the disk has free boundaries and is strongly pressure confined, the mixed GI is dominated by the distortional mode that is surface-gravity waves driven unstable under their own gravity and thus incompressible. We demonstrate that the Jeans mode is gravity-modified acoustic waves rather than inertial waves and that inertial waves are almost unaffected by self-gravity. We derive an analytic expression for the effective sound speed c eff of acoustic-surface-gravity waves. We also find expressions for the gravity reduction factors relative to a razor-thin counterpart that are appropriate for the Jeans and distortional modes. The usual razor-thin dispersion relation, after correcting for c eff and the reduction factors, closely matches the numerical results obtained by solving a full set of linearized equations. The effective sound speed generalizes the Toomre stability parameter of the Jeans mode to allow for the mixed GI of vertically stratified, pressure-confined disks.

Kim, Jeong-Gyu; Kim, Woong-Tae; Seo, Young Min; Hong, Seung Soo

2012-12-01

52

The Homologousness of Polytropic Gaseous Spheres in the General-Relativistic Case  

NASA Astrophysics Data System (ADS)

TOV equations in the polytropic case (P = K?1+1/N) are represented by the homologous invariants of U, V, and an additional one of w = P / ( ?c2), where P and ?c2 are the pressure and the static energy density. The homologous core solutions form a curved surface in the space of (U, V, w), and they are distinguished by the asymptotic surface values of E ( = UV N ) and D ( = wV ). U, V, and w lead the invariant variables of x and ?, expressing the radius and the mass function. The solution of x and ? with a central value of wc, called the core bundle solution (CB), well describes the extreme general-relativistic state. Core solutions are represented by the usual Emden variables, defined by ? = ? ? N and P = K ?1+1/N ? N+1, as the general-relativistic E-solution (gE), which are determined by the two parameters ?c and ? ( = K ? 1/N ). However, these two parameters change into each other by a homologous transformation, under the condition of wc = ?c?. Hence, the gE solutions form a continuous group of one-parameter families, one of which is a CB solution corresponding to the gE solution with ? = 1, and another of which the general-relativisitic Lane-Emden solutions (gLE), defined by gE solutions with ?c = 1. A gLE solution changes into a CB solution by homologous transformation between each other. In gLE, three ways of ? = ( K-1? )N, ?c, and pc?-1 render the normalization by K N/2, ?c-1/2, and pc-1/2, respectively, so that three kinds of mass-radius relations, derived from each normalization, weave the mass-radius textile in the (M, R, ?) space, where it stands up besides the Schwarzschild-radius wall.

Kondo, Masa-Aki

2008-08-01

53

Self-similar evolution of interplanetary magnetic clouds and Ulysses measurements of the polytropic index inside the cloud  

NASA Technical Reports Server (NTRS)

A self similar model for the expanding flux rope is developed for a magnetohydrodynamic model of interplanetary magnetic clouds. It is suggested that the dependence of the maximum magnetic field on the distance from the sun and the polytropic index gamma has the form B = r exp (-1/gamma), and that the ratio of the electron temperature to the proton temperature increases with distance from the sun. It is deduced that ion acoustic waves should be observed in the cloud. Both predictions were confirmed by Ulysses observations of a 1993 magnetic cloud. Measurements of gamma inside the cloud demonstrate sensitivity to the internal topology of the magnetic field in the cloud.

Osherovich, Vladimir A.; Fainberg, J.; Stone, R. G.; MacDowall, R. J.; Berdichevsky, D.

1997-01-01

54

Baryon currents in QCD with compact dimensions  

SciTech Connect

On a compact space with nontrivial cycles, for sufficiently small values of the radii of the compact dimensions, SU(N) gauge theories coupled with fermions in the fundamental representation spontaneously break charge conjugation, time reversal, and parity. We show at one loop in perturbation theory that a physical signature for this phenomenon is a nonzero baryonic current wrapping around the compact directions. The persistence of this current beyond the perturbative regime is checked by lattice simulations.

Lucini, B. [Physics Department, Swansea University, Singleton Park, Swansea SA2 8PP (United Kingdom); Patella, A. [Scuola Normale Superiore, Piazza dei Cavalieri 27, 56126 Pisa (Italy); Istituto Nazionale Fisica Nucleare Sezione di Pisa, Largo Pontecorvo 3, 56126 Pisa (Italy); Pica, C. [Physics Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

2007-06-15

55

The evolution of highly compact binary stellar systems  

NASA Technical Reports Server (NTRS)

A new theoretical treatment of the evolution of highly compact binary systems is presented. The evolution is calculated until almost the entire mass of the secondary has been transferred to the primary or lost from the system. It is assumed that gravitational radiation from the system is the cause of mass transfer. It is found that the structure of the mass-losing star can be approximated by an n = 3/2 polytrope, and as a result a relatively large number of different cases can be explored and some general conclusions drawn. An explanation is found for the existence of a cutoff in the orbital period distribution among the cataclysmic variables and light is shed upon the possible generic relationships among cataclysmic variables, the low-mass X-ray binaries, and the spectrally soft transient X-ray sources.

Rappaport, S.; Joss, P. C.; Webbink, R. F.

1982-01-01

56

Compact magnetograph  

NASA Technical Reports Server (NTRS)

A compact magnetograph system based on solid Fabry-Perot interferometers as the spectral isolation elements was studied. The theory of operation of several Fabry-Perot systems, the suitability of various magnetic lines, signal levels expected for different modes of operation, and the optimal detector systems were investigated. The requirements that the lack of a polarization modulator placed upon the electronic signal chain was emphasized. The PLZT modulator was chosen as a satisfactory component with both high reliability and elatively low voltage requirements. Thermal control, line centering and velocity offset problems were solved by a Fabry-Perot configuration.

Title, A. M.; Gillespie, B. A.; Mosher, J. W.

1982-01-01

57

An Empirical Polytrope Law for Solar Wind Thermal Electrons Between 0.45 and 4.76 AU: Voyager 2 and Mariner 10  

Microsoft Academic Search

Empirical evidence is presented that solar wind thermal electrons obey a polrope law of the form P -- n ß with polytrope index ¾ -- 1.175 _+ 0.03 (30). The Voyager 2 and Mariner 10 data used span the radial range from 0.45 to 4.76 AU and have a large dynamic range in density (four decades), and in temper- ature

E. C. Sittler; J. D. Scudder

1980-01-01

58

Compact torus  

SciTech Connect

The objective of the compact torus approach is to provide toroidal magnetic-field configurations that are based primarily on plasma currents and can be freed from closely surrounding mechanical structures. Some familiar examples are the current-carrying plasma rings of reversed-field theta pinches and relativistic-electron smoke ring experiments. The spheromak concept adds an internal toroidal magnetic field component, in order to enhance MHD stability. In recent experiments, three different approaches have been used to generate spheromak plasmas: (1) the reversed-field theta pinch; (2) the coaxial plasma gun; (3) a new quasi-static method, based on the initial formation of a toroidal plasma sleeve around a mechanical ring that generates poloidal and toroidal fluxes, followed by field-line reconnection to form a detached spheromak plasma. The theoretical and experimental MHD stability results for the spheromak configuration are found to have common features.

Furth, H.P.

1980-10-01

59

Sgp3 and TLR7 Stimulation Differentially Alter the Expression Profile of Modified Polytropic Retroviruses Implicated in Murine Systemic Lupus  

PubMed Central

The envelope glycoprotein, gp70, of endogenous retroviruses represents one of the major nephritogenic autoantigens implicated in murine systemic lupus erythematosus. Among different endogenous retroviruses (ecotropic, xenotropic and polytropic), lupus-prone mice express remarkably high levels of modified polytropic (mPT) retroviruses, which are controlled by the Sgp3 (serum gp70 production) locus. To define the ontribution of the Sgp3 locus derived from lupus-prone mice to the expression of the specific mPT proviruses, the genetic origin of different mPT viruses expressed in livers and thymi of wild-type and Sgp3 congenic C57BL/6 mice was determined through clonal analysis of their transcripts. Among 13 mPT proviruses present in the C57BL/6 genome, only 3 proviruses (Mpmv6, Mpmv10 and Mpmv13) were selectively but differentially expressed in livers and thymi. This was likely a result of co-regulated expression with host genes because of their integration in the same transcriptional direction. In contrast, Sgp3 induced the steady-state expression of an additional select group of mPT proviruses and, after stimulation of TLR7, the highly upregulated expression of a potentially replication-competent mPT virus Mpmv4. These results indicated that the expression of distinct subpopulations of mPT retroviruses was regulated by Sgp3- and TLR7-dependent mechanisms. The induction of potentially replication-competent mPT viruses and the upregulation of one such virus after stimulation with TLR7 in Sgp3 congenic mice further highlight the implication of Sgp3 in autoimmune responses against nephritogenic serum gp70 through the activation of TLR7. PMID:22503566

Leroy, Valerie; Kihara, Masao; Baudino, Lucie; Evans, Leonard H.; Izui, Shozo

2012-01-01

60

Xpr1 is an atypical G-protein-coupled receptor that mediates xenotropic and polytropic murine retrovirus neurotoxicity.  

PubMed

Xenotropic murine leukemia virus-related virus (XMRV) was first identified in human prostate cancer tissue and was later found in a high percentage of humans with chronic fatigue syndrome (CFS). While exploring potential disease mechanisms, we found that XMRV infection induced apoptosis in SY5Y human neuroblastoma cells, suggesting a mechanism for the neuromuscular pathology seen in CFS. Several lines of evidence show that the cell entry receptor for XMRV, Xpr1, mediates this effect, and chemical cross-linking studies show that Xpr1 is associated with the G? subunit of the G-protein heterotrimer. The activation of adenylate cyclase rescued the cells from XMRV toxicity, indicating that toxicity resulted from reduced G-protein-mediated cyclic AMP (cAMP) signaling. Some proteins with similarity to Xpr1 are involved in phosphate uptake into cells, but we found no role of Xpr1 in phosphate uptake or its regulation. Our results indicate that Xpr1 is a novel, atypical G-protein-coupled receptor (GPCR) and that xenotropic or polytropic retrovirus binding can disrupt the cAMP-mediated signaling function of Xpr1, leading to the apoptosis of infected cells. We show that this pathway is also responsible for the classic toxicity of the polytropic mink cell focus-forming (MCF) retrovirus in mink cells. Although it now seems clear that the detection of XMRV in humans was the result of sample contamination with a recombinant mouse virus, our findings may have relevance to neurologic disease induced by MCF retroviruses in mice. PMID:22090134

Vaughan, Andrew E; Mendoza, Ramon; Aranda, Ramona; Battini, Jean-Luc; Miller, A Dusty

2012-02-01

61

NEAR- AND FAR-FIELD RESPONSE TO COMPACT ACOUSTIC SOURCES IN STRATIFIED CONVECTION ZONES  

SciTech Connect

The role of the acoustic continuum associated with compact sources in the Sun's interior wave field is explored for a simple polytropic model. The continuum produces a near-field acoustic structure-the so-called acoustic jacket-that cannot be represented by a superposition of discrete normal modes. Particular attention is paid to monochromatic point sources of various frequency and depth, and to the surface velocity power that results, both in the discrete f- and p-mode spectrum and in the continuum. It is shown that a major effect of the continuum is to heal the surface wave field produced by compact sources, and therefore to hide them from view. It is found that the continuous spectrum is not a significant contributor to observable inter-ridge seismic power.

Cally, Paul S., E-mail: paul.cally@monash.edu [Monash Centre for Astrophysics and School of Mathematical Sciences, Monash University, Clayton, Victoria 3800 (Australia)

2013-05-01

62

Ceramic powder compaction  

SciTech Connect

With the objective of developing a predictive model for ceramic powder compaction we have investigated methods for characterizing density gradients in ceramic powder compacts, reviewed and compared existing compaction models, conducted compaction experiments on a spray dried alumina powder, and conducted mechanical tests and compaction experiments on model granular materials. Die filling and particle packing, and the behavior of individual granules play an important role in determining compaction behavior and should be incorporated into realistic compaction models. These results support the use of discrete element modeling techniques and statistical mechanics principals to develop a comprehensive model for compaction, something that should be achievable with computers with parallel processing capabilities.

Glass, S.J.; Ewsuk, K.G. [Sandia National Labs., Albuquerque, NM (United States); Mahoney, F.M. [Norton Co., Worcester, MA (United States)

1995-12-31

63

Viral RNAs Are Unusually Compact  

PubMed Central

A majority of viruses are composed of long single-stranded genomic RNA molecules encapsulated by protein shells with diameters of just a few tens of nanometers. We examine the extent to which these viral RNAs have evolved to be physically compact molecules to facilitate encapsulation. Measurements of equal-length viral, non-viral, coding and non-coding RNAs show viral RNAs to have among the smallest sizes in solution, i.e., the highest gel-electrophoretic mobilities and the smallest hydrodynamic radii. Using graph-theoretical analyses we demonstrate that their sizes correlate with the compactness of branching patterns in predicted secondary structure ensembles. The density of branching is determined by the number and relative positions of 3-helix junctions, and is highly sensitive to the presence of rare higher-order junctions with 4 or more helices. Compact branching arises from a preponderance of base pairing between nucleotides close to each other in the primary sequence. The density of branching represents a degree of freedom optimized by viral RNA genomes in response to the evolutionary pressure to be packaged reliably. Several families of viruses are analyzed to delineate the effects of capsid geometry, size and charge stabilization on the selective pressure for RNA compactness. Compact branching has important implications for RNA folding and viral assembly. PMID:25188030

Gopal, Ajaykumar; Egecioglu, Defne E.; Yoffe, Aron M.; Ben-Shaul, Avinoam; Rao, Ayala L. N.; Knobler, Charles M.; Gelbart, William M.

2014-01-01

64

An exact solution for axial flow in cylindrically symmetric, steady-state detonation in polytropic explosive with an arbitrary rate of decomposition  

Microsoft Academic Search

Methods of differential geometry and Bernoulli’s equation, written as B=0, are used to develop a new approach for constructing an exact solution for axial flow in a classical, two-dimensional, ZND detonation wave in a polytropic explosive with an arbitrary rate of decomposition. This geometric approach is fundamentally different from the traditional approaches to this axial flow problem formulated by Wood

M. Cowperthwaite

1994-01-01

65

Compact Ion and Neutron Spectrometer (CINS) for Space Applications  

E-print Network

-energy charged particles of galactic and solar origin pass through or undergo nuclear interactions transport vehicles and on planetary surfaces. Our concept for a charged particle telescope includes thick of the compact charged particle telescope showing ion species identification and energy deposition spectra. I

66

Compact plasma accelerator  

NASA Technical Reports Server (NTRS)

A compact plasma accelerator having components including a cathode electron source, an anodic ionizing gas source, and a magnetic field that is cusped. The components are held by an electrically insulating body having a central axis, a top axial end, and a bottom axial end. The cusped magnetic field is formed by a cylindrical magnet having an axis of rotation that is the same as the axis of rotation of the insulating body, and magnetized with opposite poles at its two axial ends; and an annular magnet coaxially surrounding the cylindrical magnet, magnetized with opposite poles at its two axial ends such that a top axial end has a magnetic polarity that is opposite to the magnetic polarity of a top axial end of the cylindrical magnet. The ionizing gas source is a tubular plenum that has been curved into a substantially annular shape, positioned above the top axial end of the annular magnet such that the plenum is centered in a ring-shaped cusp of the magnetic field generated by the magnets. The plenum has one or more capillary-like orifices spaced around its top such that an ionizing gas supplied through the plenum is sprayed through the one or more orifices. The plenum is electrically conductive and is positively charged relative to the cathode electron source such that the plenum functions as the anode; and the cathode is positioned above and radially outward relative to the plenum.

Foster, John E. (Inventor)

2004-01-01

67

Compact hybrid particulate collector (COHPAC)  

SciTech Connect

This patent describes a method for retrofit filtering of particulates in a flue gas from a combustion source having an existing conventional electrostatic precipitator connected thereto and a smoke stack connected to the precipitator. It comprises: removing at least one discharge electrode and collecting electrode from within the housing of the electrostatic precipitator; attaching a tubesheet within the housing; supporting a compact baghouse filter within the separate filter section by the tubesheet; whereby the remaining discharge electrodes and corresponding collecting electrodes in the electrostatis precipitator serve to remove a majority of particulates form the flue gas and impart a residual charge on remaining particulates discharged to the separate filter section, and the remaining particulates are collected by the baghouse filter before the residual electric charge substantially dissipates.

Chang, R.

1992-10-27

68

High-frequency behavior of w-mode pulsations of compact stars  

E-print Network

We study the asymptotic behavior of the quasi-normal modes (QNMs) of w-mode pulsations of compact stars in the high-frequency regime. We observe that both the axial and polar w-mode QNMs attain similar asymptotic behaviors in spite of the fact that they are described by two totally different differential equation systems. We obtain robust asymptotic formulae relating w-mode QNMs of different polarities and different angular momenta. To explore the physical reason underlying such similarity, we first derive a high-frequency approximation for the polar w-mode oscillations to unify the descriptions for both cases. Then, we develop WKB-type analyses for them and quantitatively explain the observed asymptotic behaviors for polytropic stars and quark stars. We also point out that such asymptotic behaviors for realistic stars are strongly dependent on the equation of state near the stellar surface.

Y. J. Zhang; J. Wu; P. T. Leung

2011-01-01

69

Xenotropic and polytropic murine leukemia virus-related sequences are not detected in the majority of patients with chronic fatigue syndrome.  

PubMed

XMRV and polytropic MLV-related virus have been controversially associated with chronic fatigue syndrome (CFS). Subsequent reports failed to detect XMRV and MLV-related virus in CFS patients, and the previous results have been interpreted as a massive laboratory contamination by mouse DNA sequences. Among 12 sequential CFS patients, two were positive for XMRV/MLV sequences. In contrast, 40 selected control subjects were negative. CSF patients and controls were negative for mitochondrial mouse-specific DNA sequences. These findings do not confirm the high frequency of MLV-related viruses infection in CFS patients, but also contrast the widespread laboratory contamination previously suggested. PMID:22842604

Paolucci, Stefania; Piralla, Antonio; Zanello, Cinzia; Minoli, Lorenzo; Baldanti, Fausto

2012-07-01

70

On Charged Mesoscopic Metallic Bubbles  

E-print Network

We investigate the existence of stable charged metallic bubbles using the shell correction method. We find that for a given mesoscopic system of n atoms of a given metal and q less n (positive) elementary charges, a metallic bubble turns out to have a lower total energy than a compact spherical cluster, whenever the charge number q is larger than acritical charge number q_c. For a magic number (n-q) of free electrons, the spherical metallic bubble may become stable against fission.

Krzysztof Pomorski; Klaus Dietrich

1997-11-14

71

Multipolar universal relations between f-mode frequency and tidal deformability of compact stars  

E-print Network

Though individual stellar parameters of compact stars usually demonstrate obvious dependence on the equation of state (EOS), EOS-insensitive universal formulas relating these parameters remarkably exist. In the present paper, we explore the inter-relationship between two such formulas, namely the f-I relation connecting the $f$-mode quadrupole oscillation frequency $\\omega_2$ and the moment of inertia $I$, and the I-Love-Q relations relating $I$, the quadrupole tidal deformability $\\lambda_2$, and the quadrupole moment $Q$, which have been proposed by Lau et al. [Astrophys. J. {\\bf 714}, 1234 (2010)], and Yagi and Yunes [Science, {\\bf 341}, 365 (2013)], respectively. A relativistic universal relation between $\\omega_l$ and $\\lambda_l$ with the same angular momentum $l=2,3,\\ldots$, the so called "diagonal f-Love relation" that holds for realistic compact stars and stiff polytropic stars, is unveiled here. An in-depth investigation in the Newtonian limit is further carried out to pinpoint its underlying physical mechanism and hence leads to a unified f-I-Love relation. We reach the conclusion that these EOS-insensitive formulas stem from a common physical origin --- compact stars can be considered as quasi-incompressible when they react to slow time variations introduced by $f$-mode oscillations, tidal forces and rotations.

T. K. Chan; Y. -H. Sham; P. T. Leung; L. -M. Lin

2014-08-17

72

Non-conformally flat initial data for binary compact objects  

E-print Network

A new method is described for constructing initial data for a binary neutron-star (BNS) system in quasi-equilibrium circular orbit. Two formulations for non-conformally flat data, waveless (WL) and near-zone helically symmetric (NHS), are introduced; in each formulation, the Einstein-Euler system, written in 3+1 form on an asymptotically flat spacelike hypersurface, is exactly solved for all metric components, including the spatially non-conformally flat potentials, and for irrotational flow. A numerical method applicable to both formulations is explained with an emphasis on the imposition of a spatial gauge condition. Results are shown for solution sequences of irrotational BNS with matter approximated by parametrized equations of state that use a few segments of polytropic equations of state. The binding energy and total angular momentum of solution sequences computed within the conformally flat -- Isenberg-Wilson-Mathews (IWM) -- formulation are closer to those of the third post-Newtonian (3PN) two point particles up to the closest orbits, for the more compact stars, whereas sequences resulting from the WL/NHS formulations deviate from the 3PN curve even more for the sequences with larger compactness. We think it likely that this correction reflects an overestimation in the IWM formulation as well as in the 3PN formula, by $\\sim 1$ cycle in the gravitational wave phase during the last several orbits. The work suggests that imposing spatial conformal flatness results in an underestimate of the quadrupole deformation of the components of binary neutron-star systems in the last few orbits prior to merger.

Koji Uryu; Francois Limousin; John L. Friedman; Eric Gourgoulhon; Masaru Shibata

2009-08-05

73

Thermodynamics of magnetized binary compact objects  

SciTech Connect

Binary systems of compact objects with electromagnetic field are modeled by helically symmetric Einstein-Maxwell spacetimes with charged and magnetized perfect fluids. Previously derived thermodynamic laws for helically symmetric perfect-fluid spacetimes are extended to include the electromagnetic fields, and electric currents and charges; the first law is written as a relation between the change in the asymptotic Noether charge {delta}Q and the changes in the area and electric charge of black holes, and in the vorticity, baryon rest mass, entropy, charge and magnetic flux of the magnetized fluid. Using the conservation laws of the circulation of magnetized flow found by Bekenstein and Oron for the ideal magnetohydrodynamic fluid, and also for the flow with zero conducting current, we show that, for nearby equilibria that conserve the quantities mentioned above, the relation {delta}Q=0 is satisfied. We also discuss a formulation for computing numerical solutions of magnetized binary compact objects in equilibrium with emphasis on a first integral of the ideal magnetohydrodynamic-Euler equation.

Uryu, Koji [Department of Physics, University of the Ryukyus, Senbaru, Nishihara, Okinawa 903-0213 (Japan); Gourgoulhon, Eric [Laboratoire Univers et Theories, UMR 8102 du CNRS, Observatoire de Paris, Universite Paris Diderot, F-92190 Meudon (France); Markakis, Charalampos [Department of Physics, University of Wisconsin-Milwaukee, Post Office Box 413, Milwaukee, Wisconsin 53201 (United States)

2010-11-15

74

DNA compaction by azobenzene-containing surfactant  

NASA Astrophysics Data System (ADS)

We report on the interaction of cationic azobenzene-containing surfactant with DNA investigated by absorption and fluorescence spectroscopy, dynamic light scattering, and atomic force microscopy. The properties of the surfactant can be controlled with light by reversible switching of the azobenzene unit, incorporated into the surfactant tail, between a hydrophobic trans (visible irradiation) and a hydrophilic cis (UV irradiation) configuration. The influence of the trans-cis isomerization of the azobenzene on the compaction process of DNA molecules and the role of both isomers in the formation and colloidal stability of DNA-surfactant complexes is discussed. It is shown that the trans isomer plays a major role in the DNA compaction process. The influence of the cis isomer on the DNA coil configuration is rather small. The construction of a phase diagram of the DNA concentration versus surfactant/DNA charge ratio allows distancing between three major phases: colloidally stable and unstable compacted globules, and extended coil conformation. There is a critical concentration of DNA above which the compacted globules can be hindered from aggregation and precipitation by adding an appropriate amount of the surfactant in the trans configuration. This is because of the compensation of hydrophobicity of the globules with an increasing amount of the surfactant. Below the critical DNA concentration, the compacted globules are colloidally stable and can be reversibly transferred with light to an extended coil state.

Zakrevskyy, Yuriy; Kopyshev, Alexey; Lomadze, Nino; Morozova, Elena; Lysyakova, Ludmila; Kasyanenko, Nina; Santer, Svetlana

2011-08-01

75

Compact turbidity meter  

NASA Technical Reports Server (NTRS)

Proposed monitor that detects back-reflected infrared radiation makes in situ turbidity measurements of lakes, streams, and other bodies of water. Monitor is compact, works well in daylight as at night, and is easily operated in rough seas.

Hirschberg, J. G.

1979-01-01

76

Compact Disc Interactive.  

ERIC Educational Resources Information Center

This overview of a digital optical storage medium with a multimedia capability includes a global description of specifications, current status, and elements required to make a CD-I (compact disk interactive) launch possible. (Author/CLB)

Valk, Anton

1987-01-01

77

Countable choice and compactness  

Microsoft Academic Search

We work in set-theory without choice ZF. Denoting by AC(N) the countable axiom of choice, we show in ZF+AC(N) that the closed unit ball of a uniformly convex Banach space is compact in the convex topology (an alternative to the weak topology in ZF). We prove that this ball is (closely) convex-compact in the convex topology. Given a set I,

Marianne Morillon

2008-01-01

78

Reply to "Comment on the Paper ''On the Determination of Electron Polytrope Indices Within Coronal Mass Ejections in the Solar Wind'"'. Appendix 5  

NASA Technical Reports Server (NTRS)

We strongly disagree with the essence of the Osherovich (hereafter Osherovich) comment on one of our papers. The following paragraphs provide the basis of our disagreement and elaborate on why we believe that none of the concluding statements in his Comment are true. Our most important point is that one can apply the model developed by Osherovich and colleagues to real data obtained at a single point in space to determine the polytropic index within magnetic clouds if and only if the highly idealized assumptions of that model conform to physical reality. There is good reason to believe that those assumptions do not provide an accurate physical description of real magnetic clouds in the spherically expanding solar wind.

Gosling, J. T.; Riley, P.; Skoug, R. M.

2001-01-01

79

Selective Up-regulation of Intact, but not Defective env RNAs of Endogenous Modified Polytropic Retrovirus by the Sgp3 Locus of Lupus-prone Mice1  

PubMed Central

Endogenous retroviruses are implicated in the pathogenesis of systemic lupus erythematosus (SLE). Since four different classes of endogenous retroviruses, i.e. ecotropic, xenotropic, polytropic (PT) or modified polytropic (mPT), are expressed in mice, we investigated the possibility that a particular class of endogenous retroviruses is associated with the development of murine SLE. We observed more than 15-fold increased expression of mPT env (envelope) RNA in livers of all four lupus-prone mice, as compared with those of nine non-autoimmune strains of mice. This was not the case for the three other classes of retroviruses. Furthermore, we found that in addition to intact mPT transcripts, many strains of mice expressed two defective mPT env transcripts which carry a deletion in the env sequence of the 3’ portion of the gp70 surface protein and the 5’ portion of the p15E transmembrane protein, respectively. Remarkably, in contrast to non-autoimmune strains of mice, all four lupus-prone mice expressed abundant levels of intact mPT env transcripts, but only low or non-detectable levels of the mutant env transcripts. The Sgp3 (serum gp70 production 3) locus derived from lupus-prone mice was responsible for the selective up-regulation of the intact mPT env RNA. Finally, we observed that single-stranded RNA-specific TLR7 played a critical role in the production of anti-gp70 autoantibodies. These data suggest that lupus-prone mice may possess a unique genetic mechanism responsible for the expression of mPT retroviruses, which could act as a triggering factor through activating TLR7 for the development of autoimmune responses in mice predisposed to SLE. PMID:19494335

Yoshinobu, Kumiko; Baudino, Lucie; Santiago-Raber, Marie-Laure; Morito, Naoki; Dunand-Sauthier, Isabelle; Morley, Bernard J.; Evans, Leonard H.; Izui, Shozo

2009-01-01

80

A multicenter blinded analysis indicates no association between chronic fatigue syndrome/myalgic encephalomyelitis and either xenotropic murine leukemia virus-related virus or polytropic murine leukemia virus.  

PubMed

The disabling disorder known as chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME) has been linked in two independent studies to infection with xenotropic murine leukemia virus-related virus (XMRV) and polytropic murine leukemia virus (pMLV). Although the associations were not confirmed in subsequent studies by other investigators, patients continue to question the consensus of the scientific community in rejecting the validity of the association. Here we report blinded analysis of peripheral blood from a rigorously characterized, geographically diverse population of 147 patients with CFS/ME and 146 healthy subjects by the investigators describing the original association. This analysis reveals no evidence of either XMRV or pMLV infection. IMPORTANCE Chronic fatigue syndrome/myalgic encephalomyelitis has an estimated prevalence of 42/10,000 in the United States, with annual direct medical costs of $7 billion. Here, the original investigators who found XMRV and pMLV (polytropic murine leukemia virus) in blood of subjects with this disorder report that this association is not confirmed in a blinded analysis of samples from rigorously characterized subjects. The increasing frequency with which molecular methods are used for pathogen discovery poses new challenges to public health and support of science. It is imperative that strategies be developed to rapidly and coherently address discoveries so that they can be carried forward for translation to clinical medicine or abandoned to focus resource investment more productively. Our study provides a paradigm for pathogen dediscovery that may be helpful to others working in this field. PMID:22991430

Alter, Harvey J; Mikovits, Judy A; Switzer, William M; Ruscetti, Francis W; Lo, Shyh-Ching; Klimas, Nancy; Komaroff, Anthony L; Montoya, Jose G; Bateman, Lucinda; Levine, Susan; Peterson, Daniel; Levin, Bruce; Hanson, Maureen R; Genfi, Afia; Bhat, Meera; Zheng, HaoQiang; Wang, Richard; Li, Bingjie; Hung, Guo-Chiuan; Lee, Li Ling; Sameroff, Stephen; Heneine, Walid; Coffin, John; Hornig, Mady; Lipkin, W Ian

2012-01-01

81

'Stutter timing' for charge decay time measurement  

NASA Astrophysics Data System (ADS)

The paper describes the approach of 'stutter timing' that has been developed to improve the accuracy of measuring charge decay times in the presence of noise in compact and portable charge decay test instrumentation. The approach involves starting and stopping the timing clock as the noisy signal rises above and falls below the target threshold voltage level.

Chubb, John; Harbour, John; Pavey, Ian

2011-06-01

82

Physically Detached "Compact Groups"  

E-print Network

A small fraction of galaxies appear to reside in dense compact groups, whose inferred crossing times are much shorter than a Hubble time. These short crossing times have led to considerable disagreement about the dynamical state of these systems. We suggest that many of the observed groups are not physically bound but are chance projections of galaxies well-separated along the line of sight. Unlike earlier similar proposals, ours does not require that the galaxies in the compact group be members of a more diffuse, but physically bound entity. The probability of physically separated galaxies projecting into an apparent compact group is non-negligible if most galaxies are distributed, as observed, in thin filaments. We illustrate this general point with a specific example: a simulation of a cold dark matter universe, in which hydrodynamic effects are included to identify galaxies. The simulated galaxy distribution is filamentary, and end-on views of these filaments produce apparent galaxy associations that have sizes and velocity dispersions similar to those of observed compact groups. The frequency of such projections can explain the observed space-density of groups in the Hickson catalog. We discuss the implications of our proposal for the formation and evolution of groups and elliptical galaxies. The proposal can be tested by using redshift-independent distance estimators to measure the line-of-sight spatial extent of nearby compact groups.

Lars Hernquist; Neal Katz; David Weinberg

1994-07-20

83

Grain charging in protoplanetary discs  

NASA Astrophysics Data System (ADS)

Context. Recent work identified a growth barrier for dust coagulation that originates in the electric repulsion between colliding particles. Depending on its charge state, dust material may have the potential to control key processes towards planet formation such as magnetohydrodynamic (MHD) turbulence and grain growth, which are coupled in a two-way process. Aims: We quantify the grain charging at different stages of disc evolution and differentiate between two very extreme cases: compact spherical grains and aggregates with fractal dimension Df = 2. Methods: Applying a simple chemical network that accounts for collisional charging of grains, we provide a semi-analytical solution. This allowed us to calculate the equilibrium population of grain charges and the ionisation fraction efficiently. The grain charging was evaluated for different dynamical environments ranging from static to non-stationary disc configurations. Results: The results show that the adsorption/desorption of neutral gas-phase heavy metals, such as magnesium, effects the charging state of grains. The greater the difference between the thermal velocities of the metal and the dominant molecular ion, the greater the change in the mean grain charge. Agglomerates have more negative excess charge on average than compact spherical particles of the same mass. The rise in the mean grain charge is proportional to N1/6 in the ion-dust limit. We find that grain charging in a non-stationary disc environment is expected to lead to similar results. Conclusions: The results indicate that the dust growth and settling in regions where the dust growth is limited by the so-called "electro-static barrier" do not prevent the dust material from remaining the dominant charge carrier.

Ilgner, M.

2012-02-01

84

Soil compaction verification  

SciTech Connect

While conducting their maintenance activities, utilities must break and restore pavement. During pavement restoration it is vitally important to ensure adequate compaction of the soil. To ensure that specified standards are met, tests have evolved that are well-suited to highway construction, but poorly suited to utility operations. A novel approach that attempts to address this problem is being tested. In the course of an intensive experimental effort it was found that relatively simple, inexpensive devices could be used to verify compaction in a wide variety of soils. Further confirmatory work has been scheduled.

Todres, H.A.

1986-01-01

85

Compact Ultradense Matter Impactors  

NASA Astrophysics Data System (ADS)

We study interactions of meteorlike compact ultradense objects (CUDO), having nuclear or greater density, with Earth and other rocky bodies in the Solar System as a possible source of information about novel forms of matter. We study the energy loss in CUDO puncture of the body and discuss differences between regular matter and CUDO impacts.

Rafelski, Johann; Labun, Lance; Birrell, Jeremiah

2013-03-01

86

Threads in compact semigroups  

Microsoft Academic Search

In this note we show that if S is a compact connected topological semigroup with unit, in which each subgroup is totally disconnected, then S contains a standard thread which meets the minimal ideal K and contains the unit. This is an extension of a previous result of the author [5] in which threads are constructed in partially ordered semigroups

Robert J. Koch

1964-01-01

87

NSTX LTXPEGASUS Compact CTF  

E-print Network

ST-PoP NSTX LTXPEGASUS ST-DEMO ARIES-ST Compact CTF ST-CTF ST-PE NHTX Spherical Torus Fusion;Investigating Innovative Solutions for NHTX/CTF and DEMO NSTX with ITER-level heat flux PEGASUS Gun Start-ST) at 3 - 4 MA range provides cost effective physics / technology basis in support for CTF and DEMO

Princeton Plasma Physics Laboratory

88

Limestone compaction: an enigma  

USGS Publications Warehouse

Compression of an undisturbed carbonate sediment core under a pressure of 556 kg/cm2 produced a “rock” with sedimentary structures similar to typical ancient fine-grained limestones. Surprisingly, shells, foraminifera, and other fossils were not noticeably crushed, which indicates that absence of crushed fossils in ancient limestones can no longer be considered evidence that limestones do not compact.

Shinn, Eugene A.; Halley, Robert B.; Hudson, J. Harold; Lidz, Barbara H.

1977-01-01

89

Compact fusion reactors  

SciTech Connect

Compact, high-power-density approaches to fusion power are proposed to improve economic viability through the use of less-advanced technology in systems of considerably reduced scale. The rationale for and the means by which these systems can be achieved are discussed, as are unique technological problems.

Krakowski, R.A.; Hafenson, R.L.

1983-09-01

90

Compact fusion reactors  

SciTech Connect

Compact, high-power-density approaches to fusion power are proposed to improve economic viability through the use of less-advanced technology in systems of considerably reduced scale. The rationale for and the means by which these systems can be achieved are discussed, as are unique technological problems.

Krakowski, R.A.; Hagenson, R.L.

1983-01-01

91

Fuel assembly skeleton compaction  

Microsoft Academic Search

The fuel assembly skeleton compaction system provides a means for remotely dismantling an irradiated nuclear fuel assembly skeleton once the nuclear fuel rods have been removed therefrom while the skeleton remains submerged in a coolant. The system comprises a feed chamber for holding the spent fuel assembly skeleton and for feeding a spent fuel assembly skeleton into a shear chamber

J. J. Wilhelm; R. F. Antol; A. Kapoor; R. M. Kobuck; G. W. Norris

1985-01-01

92

COMPACT FACTORS IN FINALLY COMPACT PRODUCTS OF TOPOLOGICAL SPACES  

E-print Network

COMPACT FACTORS IN FINALLY COMPACT PRODUCTS OF TOPOLOGICAL SPACES Paolo Lipparini We present that if a product is regu- lar and Lindel¨of then all but at most countably many factors are compact. We generalize that if a product of topological spaces is Lindel¨of then each factor is Lindel¨of. What is relevant to the present

Lipparini, Paolo

93

MAZUR INTERSECTION PROPERTIES FOR COMPACT AND WEAKLY COMPACT CONVEX SETS  

Microsoft Academic Search

Various authors have studied when a Banach space can be renormed so that every weakly compact convex, or less restrictively every compact convex set is an intersection of balls. We first observe that each Banach space can be renormed so that every weakly compact convex set is an intersection of balls, and then we introduce and study properties that are

JON VANDERWERFF

1998-01-01

94

A pedagogical history of compactness  

E-print Network

This paper traces the history of compactness from the original motivating questions, through the development of the definition, to a generalization of sequential compactness in terms of nets and filters.

Sundstrom, Manya Raman

2010-01-01

95

Super-Compact Laser  

NASA Technical Reports Server (NTRS)

Microcosm, Inc. produced the portable Farfield-2 laser for field applications that require high power pulsed illumination. The compact design was conceived through research at Goddard Space Flight Center on laser instruments for space missions to carry out geoscience studies of Earth. An exclusive license to the key NASA patent for the compact laser design was assigned to Microcosm. The FarField-2 is ideal for field applications, has low power consumption, does not need water cooling or gas supplies, and produces nearly ideal beam quality. The properties of the laser also make it effective over long distances, which is one reason why NASA developed the technology for laser altimeters that can be toted aboard spacecraft. Applications for the FarField-2 include medicine, biology, and materials science and processing, as well as diamond marking, semiconductor line-cutting, chromosome surgery, and fluorescence microscopy.

1997-01-01

96

Compact spreader schemes  

NASA Astrophysics Data System (ADS)

This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

Placidi, M.; Jung, J.-Y.; Ratti, A.; Sun, C.

2014-12-01

97

Compact toroid formation experiments  

Microsoft Academic Search

Summary form only given, as follows. A compact toroid (CT) formation experiment is discussed. The device has coaxial electrode diameters of 0.9 m (inner) and 1.25 m (outer) and an electrode length of ~1.2 m, including an expansion drift section. The CT is formed by a 0.1-0.2-T initial radial magnetic field embedded coaxial puff gas discharge. The gas puff is

J. H. Degnan; G. P. Baca; J. D. Beason; M. E. Dearborn; D. Dietz; K. E. Hackett; J. L. Holmes; B. W. Mullins; J. L. Mullins; E. L. Ruden; D. W. Price; C. R. Sovinec; D. Gale; J. D. Graham; D. Ralph; M. Scott; W. Sommars; G. Bird; S. K. Coffey; S. W. Seiler; G. F. Kiuttu; R. E. Peterkin; N. F. Roderick; P. Turchi

1990-01-01

98

Compact infrared detector  

NASA Technical Reports Server (NTRS)

Broadband IR detector integrated into compact package for pollution monitoring and weather prediction is small, highly responsive, and immune to high noise. Sensing material is transparent sheet metalized with reflecting coating and overcoated with black material on same side. Pulse produced by chopping of infrared source beam creates transient "thermal lens" that temporarily defocuses laser beam probe. Detector monitoring beam measures defocusing which parallels infrared intensity.

Gupta, A.; Hong, S.; Moacanin, J.

1981-01-01

99

Serologic and PCR testing of persons with chronic fatigue syndrome in the United States shows no association with xenotropic or polytropic murine leukemia virus-related viruses  

PubMed Central

In 2009, a newly discovered human retrovirus, xenotropic murine leukemia virus (MuLV)-related virus (XMRV), was reported by Lombardi et al. in 67% of persons from the US with chronic fatigue syndrome (CFS) by PCR detection of gag sequences. Although six subsequent studies have been negative for XMRV, CFS was defined more broadly using only the CDC or Oxford criteria and samples from the US were limited in geographic diversity, both potentially reducing the chances of identifying XMRV positive CFS cases. A seventh study recently found polytropic MuLV sequences, but not XMRV, in a high proportion of persons with CFS. Here we tested blood specimens from 45 CFS cases and 42 persons without CFS from over 20 states in the United States for both XMRV and MuLV. The CFS patients all had a minimum of 6 months of post-exertional malaise and a high degree of disability, the same key symptoms described in the Lombardi et al. study. Using highly sensitive and generic DNA and RNA PCR tests, and a new Western blot assay employing purified whole XMRV as antigen, we found no evidence of XMRV or MuLV in all 45 CFS cases and in the 42 persons without CFS. Our findings, together with previous negative reports, do not suggest an association of XMRV or MuLV in the majority of CFS cases. PMID:21342521

2011-01-01

100

Compact Plasma Accelerator  

NASA Technical Reports Server (NTRS)

A plasma accelerator has been conceived for both material-processing and spacecraft-propulsion applications. This accelerator generates and accelerates ions within a very small volume. Because of its compactness, this accelerator could be nearly ideal for primary or station-keeping propulsion for spacecraft having masses between 1 and 20 kg. Because this accelerator is designed to generate beams of ions having energies between 50 and 200 eV, it could also be used for surface modification or activation of thin films.

Foster, John E.

2004-01-01

101

A compact SADM family  

NASA Astrophysics Data System (ADS)

Alcatel Space has developed a new SADM family driven by cost, modularity, mass and performances. The modularity concept is based on separating the rotation drive function from the electrical transfer function. The drive actuator has been designed for various applications where pointing and reliability is needed. It can be associated with high dissipative rotary devices (SA collectors, RF joints..). The design goal was to minimize the number of parts in order to reach the most simple and compact mechanism. Mass reduction was achieved by reducing as much as possible the load path between the Solar Array interface and the spacecraft interface. Following these guidelines, the drive actuator was developed and qualified on ATV SADM (part od Alcatel Space Solar Array Drive Sub System for ATV). Further more a high power integrated collector was qualified inside the SADM for Geo-stationary telecom satellite (SPACEBUS platforms). Fine thermal and mechanical modeling was necessary to predict SADM behaviors for the numerous thermal environments over the missions (steady and transient cases). These modeling were well correlated through mechanical and thermal balances qualification tests. The challenging approach of thermal dissipation in a compact design leads to a family of 3 SADM capabilities form 2kW up to 15kW per SADM weighing less than 4.5 kg each.

Barbet, Vincent; Le Quintrec, Cyrille; Jeandot, Xavier; Chaix, Alain; Grain, Eric; Roux, Jerome

2005-07-01

102

Hadrons in compact stars  

E-print Network

We discuss $\\beta$-equilibrated and charge neutral matter involving hyperons and $\\bar K$ condensates within relativistic models. It is observed that populations of baryons are strongly affected by the presence of antikaon condensates. Also, the equation of state including $\\bar K$ condensates becomes softer resulting in a smaller maximum mass neutron star.

Debades Bandyopadhyay

2005-12-28

103

Electrosintering of iron powder compacts  

NASA Astrophysics Data System (ADS)

The influence of a nominal external electric fieldE=3 to 10 kV/cm on the sintering of iron powder compacts for 30 minutes at 1140°C in a vacuum of ˜10-6 torr was investigated. It was found that the field reduced the porosity by as much as 29 to 73 pct compared to sintering without a field, the magnitude depending on the procedure employed to measure the density of the specimen. Optical microscopy revealed that the specimen electrosintered withE=10 kV/cm had a skin of ˜0.2 mm in thickness, where the porosity was significantly less than in the interior. This was also the depth of carburization that was obtained upon carburizing the electrosintered specimens. It is proposed that the decrease in porosity produced by the field results from a decrease in the chemical potential of vacancies at or just below the charged external surface. Vacancy flux equations employed to calculate the porosity as a function of distance below the external surface showed that the porosity becomes approximately zero at a distance ofx c=0.4 to 0.5 mm below the surface, which is in reasonable accord with the microscopy measurements. Similar values ofx c were obtained by assuming that the entire porosity decrease given by the density measurements occurred in a ring of thickness ofx c below the external surface. The difference in the density measured by two Archimedes-principle procedures and microscopy observations suggests that the cavities open to the external surface of the electrosintered specimens are smaller or narrower than those for specimens sintered without a field.

Fahmy, Yusef; Conrad, Hans

2001-03-01

104

WEAKLY COMPACTLY GENERATED BANACH ALGEBRAS ASSOCIATED TO LOCALLY COMPACT GROUPS  

Microsoft Academic Search

Let G be a locally compact group, and let X be any one of the Banach algebras C (G), C0(G), B(G) or A(G). We characterize the property that X, as a Banach space, is weakly compactly generated in terms of conditions on G and its dual space.

E. KANIUTH; A. T. LAU; G. SCHLICHTING

1998-01-01

105

Compact artificial hand  

NASA Technical Reports Server (NTRS)

A relatively simple, compact artificial hand, is described which includes hooks pivotally mounted on first frame to move together and apart. The first frame is rotatably mounted on a second frame to enable "turning at the wrist" movement without limitation. The second frame is pivotally mounted on a third frame to permit 'flexing at the wrist' movement. A hook-driving motor is fixed to the second frame but has a shaft that drives a speed reducer on the first frame which, in turn, drives the hooks. A second motor mounted on the second frame, turns a gear on the first frame to rotate the first frame and the hooks thereon. A third motor mounted on the third frame, turns a gear on a second frame to pivot it.

Wiker, G. A.; Mann, W. A. (inventors)

1979-01-01

106

Compact vacuum insulation  

DOEpatents

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially "point" or "line" contacts with the metal wall sheets. In the case of monolithic spacers that form "line" contacts, two such spacers with the line contacts running perpendicular to each other form effectively "point" contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

Benson, David K. (Golden, CO); Potter, Thomas F. (Denver, CO)

1993-01-01

107

Compact vacuum insulation embodiments  

DOEpatents

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially "point" or "line" contacts with the metal wall sheets. In the case of monolithic spacers that form "line" contacts, two such spacers with the line contacts running perpendicular to each other form effectively "point" contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

Benson, David K. (Golden, CO); Potter, Thomas F. (Denver, CO)

1992-01-01

108

Atacama compact array antennas  

NASA Astrophysics Data System (ADS)

The ACA (Atacama Compact Array) system is an important element of ALMA and consists of four ACA 12-m antennas and twelve ACA 7-m antennas. The ACA system aims to acquire the total power data with four 12-m antennas and the short baseline interferometer data with 7-m antennas. The ACA system also increases reliability of the interferometer maps of astronomical sources larger than the field view of the 12-m antenna. The science performance of these antennas has been extensively verified at OSF (operation support facility) at an elevation of 2900 m in Atacama desert in northern Chile since 2007. The pointing performance has been verified with a dedicated optical pointing telescope, the servo performance is tested with angle encoders, and the surface accuracy has been measured with a radio holography method. Both ACA 12-m antennas and 7-m antennas have been successfully demonstrated to meet the very stringent ALMA specifications.

Saito, M.; Inatani, J.; Nakanishi, K.; Saito, H.; Iguchi, S.

2012-09-01

109

Compact acoustic refrigerator  

DOEpatents

A compact acoustic refrigeration system actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment. 18 figs.

Bennett, G.A.

1992-11-24

110

Compact acoustic refrigerator  

DOEpatents

A compact acoustic refrigeration system actively cools components, e.g., electrical circuits (22), in a borehole environment. An acoustic engine (12, 14) includes first thermodynamic elements (12) for generating a standing acoustic wave in a selected medium. An acoustic refrigerator (16, 26, 28) includes second thermodynamic elements (16) located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements (16) and a relatively hot temperature at a second end of the second thermodynamic elements (16). A resonator volume (18) cooperates with the first and second thermodynamic elements (12, 16) to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements (12, 16), first heat pipes (24, 26) transfer heat from the heat load (22) to the second thermodynamic elements (16) and second heat pipes (28, 32) transfer heat from first and second thermodynamic elements (12, 16) to the borehole environment.

Bennett, Gloria A. (Los Alamos, NM)

1992-01-01

111

CHARGE syndrome  

Microsoft Academic Search

CHARGE syndrome was initially defined as a non-random association of anomalies (Coloboma, Heart defect, Atresia choanae, Retarded growth and development, Genital hypoplasia, Ear anomalies\\/deafness). In 1998, an expert group defined the major (the classical 4C's: Choanal atresia, Coloboma, Characteristic ears and Cranial nerve anomalies) and minor criteria of CHARGE syndrome. Individuals with all four major characteristics or three major and

Kim D Blake; Chitra Prasad

2006-01-01

112

Charge Challenge  

NSDL National Science Digital Library

In this activity, learners explore how objects can have positive, negative, or neutral charges, which attract, repel and move between objects. Learners charge various materials and observe their interactions. Winter is an ideal time to perform these experiments (because there is less water vapor in the air); if it is humid, use a hair dryer to dry the objects, surfaces, and air around the work area.

Kansas, University O.

2006-01-01

113

Charged Leptons  

E-print Network

This is the report of the Intensity Frontier Charged Lepton Working Group of the 2013 Community Summer Study "Snowmass on the Mississippi", summarizing the current status and future experimental opportunities in muon and tau lepton studies and their sensitivity to new physics. These include searches for charged lepton flavor violation, measurements of magnetic and electric dipole moments, and precision measurements of the decay spectrum and parity-violating asymmetries.

J. Albrecht; M. Artuso; K. Babu; R. H. Bernstein; T. Blum; D. N. Brown; B. C. K. Casey; C. -h. Cheng; V. Cirigliano; A. Cohen; A. Deshpande; E. C. Dukes; B. Echenard; A. Gaponenko; D. Glenzinski; M. Gonzalez-Alonso; F. Grancagnolo; Y. Grossman; R. C. Group; R. Harnik; D. G. Hitlin; B. Kiburg; K. Knoepfe; K. Kumar; G. Lim; Z. -T. Lu; D. McKeen; J. P. Miller; M. Ramsey-Musolf; R. Ray; B. L. Roberts; M. Rominsky; Y. Semertzidis; D. Stoeckinger; R. Talman; R. Van De Water; P. Winter

2013-11-21

114

HOMOGENEITY PROPERTIES ON COMPACT SPACES  

E-print Network

HOMOGENEITY PROPERTIES ON COMPACT SPACES By Ramiro H. de la Vega A dissertation submitted) at the UNIVERSITY OF WISCONSIN -- MADISON 2005 #12; i Abstract A topological space X is said to be homogeneous show that under CH there exists a compact S­space which is homogeneous, thus answering a question of V

Miller, Joseph S.

115

Engineering Prototype for a Compact Medical Dielectric Wall Accelerator  

SciTech Connect

A compact accelerator system architecture based on the dielectric wall accelerator (DWA) for medical proton beam therapy has been developed by the Compact Particle Acceleration Corporation (CPAC). The major subsystems are a Radio Frequency Quadrupole (RFQ) injector linac, a pulsed kicker to select the desired proton bunches, and a DWA linear accelerator incorporating a high gradient insulator (HGI) with stacked Blumleins to produce the required acceleration energy. The Blumleins are switched with solid state laser-driven optical switches integrated into the Blumlein assemblies. Other subsystems include a high power pulsed laser, fiber optic distribution system, electrical charging system, and beam diagnostics. An engineering prototype has been constructed and characterized, and these results will be used within the next three years to develop an extremely compact 150 MeV system capable of modulating energy, beam current, and spot size on a shot-to-shot basis. This paper presents the details the engineering prototype, experimental results, and commercialization plans.

Zografos, Anthony; Hening, Andy; Joshkin, Vladimir; Leung, Kevin; Pearson, Dave; Pearce-Percy, Henry; Rougieri, Mario; Parker, Yoko; Weir, John [CPAC, Livermore, CA (United States); Blackfield, Donald; Chen, Yu-Jiuan; Falabella, Steven; Guethlein, Gary; Poole, Brian [Lawrence Livermore National Laboratory, Livermore, CA (United States); Hamm, Robert W. [R and M Technical Enterprises, Pleasanton, CA (United States); Becker, Reinard [Scientific Software Service, Gelnhausen (Germany)

2011-12-13

116

Compact THz imaging detector  

NASA Astrophysics Data System (ADS)

We describe preliminary design, modeling and test results for the development of a monolithic, high pixel density, THz band focal plane array (FPA) fabricated in a commercial CMOS process. Each pixel unit cell contains multiple individual THz band antennae that are coupled to independent amplifiers. The amplified signals are summed either coherently or incoherently to improve detection (SNR). The sensor is designed to operate at room temperature using passive or active illumination. In addition to the THz detector, a secondary array of Visible or SWIR context imaging pixels are interposed in the same area matrix. Multiple VIS/SWIR context pixels can be fabricated within the THz pixel unit cell. This provides simultaneous, registered context imagery and "Pan sharpening" MTF enhancement for the THz image. The compact THz imaging system maximizes the utility of a ~ 300 ?m x 300 ?m pixel area associated with the optical resolution spot size for a THz imaging system operating at a nominal ~ 1.0 THz spectral frequency. RF modeling is used to parameterize the antenna array design for optimal response at the THz frequencies of interest. The quarter-wave strip balanced bow-tie antennae are optimized based on the semiconductor fabrication technology thin-film characteristics and the CMOS detector input impedance. RF SPICE models enhanced for THz frequencies are used to evaluate the predicted CMOS detector performance and optimal unit cell design architecture. The models are validated through testing of existing CMOS ROICs with calibrated THz sources.

Newman, J. Daniel; Lee, Paul P. K.; Sacco, Andrew P.; Chamberlain, Thomas B.; Willems, Dave A.; Fiete, Robert D.; Bocko, Mark V.; Ignotovic, Zeljko; Pipher, Judith L.; McMurtry, Craig W.; Zhang, Xi-Cheng; Rhodes, David B.; Ninkov, Zoran

2013-05-01

117

Rotating hybrid compact stars  

NASA Astrophysics Data System (ADS)

Starting from equations of state of nucleonic and color-superconducting quark matter and assuming a first-order phase transition between these, we construct an equation of state of stellar matter, which contains three phases: a nucleonic phase, as well as two-flavor and three-flavor color-superconducting phases of quarks. Static sequences of the corresponding hybrid stars include massive members with masses of ~2 M? and radii in the range of 13 ? R ? 16 km. We investigate the integral parameters of rapidly rotating stars and obtain evolutionary sequences that correspond to constant rest-mass stars spinning down by electromagnetic and gravitational radiation. Physically new transitional sequences are revealed that are distinguished by a phase transition from nucleonic to color-superconducting matter for some configurations that are located between the static and Keplerian limits. The snapshots of internal structure of the star, displaying the growth or shrinkage of superconducting volume as the star's spin changes, are displayed for constant rest mass stars. We further obtain evolutionary sequences of rotating supramassive compact stars and construct pre-collapse models that can be used as initial data to simulate a collapse of color-superconducting hybrid stars to a black hole.

Ayvazyan, N. S.; Colucci, G.; Rischke, D. H.; Sedrakian, A.

2013-11-01

118

Holding Charge  

NSDL National Science Digital Library

In this trick, learners discover how to stick a straw to the palm of their hand, window door, or anywhere using static electricity. This activity introduces learners to negative and positive charges and shows how opposites attract. Note: this trick works best in low humidity (dry air).

Muller, Eric

1995-01-01

119

Compact fission counter for DANCE  

SciTech Connect

The Detector for Advanced Neutron Capture Experiments (DANCE) consists of 160 BF{sub 2} crystals with equal solid-angle coverage. DANCE is a 4{pi} {gamma}-ray calorimeter and designed to study the neutron-capture reactions on small quantities of radioactive and rare stable nuclei. These reactions are important for the radiochemistry applications and modeling the element production in stars. The recognition of capture event is made by the summed {gamma}-ray energy which is equivalent of the reaction Q-value and unique for a given capture reaction. For a selective group of actinides, where the neutron-induced fission reaction competes favorably with the neutron capture reaction, additional signature is needed to distinguish between fission and capture {gamma} rays for the DANCE measurement. This can be accomplished by introducing a detector system to tag fission fragments and thus establish a unique signature for the fission event. Once this system is implemented, one has the opportunity to study not only the capture but also fission reactions. A parallel-plate avalanche counter (PPAC) has many advantages for the detection of heavy charged particles such as fission fragments. These include fast timing, resistance to radiation damage, and tolerance of high counting rate. A PPAC also can be tuned to be insensitive to {alpha} particles, which is important for experiments with {alpha}-emitting actinides. Therefore, a PPAC is an ideal detector for experiments requiring a fast and clean trigger for fission. A PPAC with an ingenious design was fabricated in 2006 by integrating amplifiers into the target assembly. However, this counter was proved to be unsuitable for this application because of issues related to the stability of amplifiers and the ability to separate fission fragments from {alpha}'s. Therefore, a new design is needed. A LLNL proposal to develop a new PPAC for DANCE was funded by NA22 in FY09. The design goal is to minimize the mass for the proposed counter and still be able to maintain a stable operation under extreme radioactivity and the ability to separate fission fragments from {alpha}'s. In the following sections, the description is given for the design and performance of this new compact PPAC, for studying the neutron-induced reactions on actinides using DANCE at LANL.

Wu, C Y; Chyzh, A; Kwan, E; Henderson, R; Gostic, J; Carter, D; Bredeweg, T; Couture, A; Jandel, M; Ullmann, J

2010-11-06

120

Compact, Reliable EEPROM Controller  

NASA Technical Reports Server (NTRS)

A compact, reliable controller for an electrically erasable, programmable read-only memory (EEPROM) has been developed specifically for a space-flight application. The design may be adaptable to other applications in which there are requirements for reliability in general and, in particular, for prevention of inadvertent writing of data in EEPROM cells. Inadvertent writes pose risks of loss of reliability in the original space-flight application and could pose such risks in other applications. Prior EEPROM controllers are large and complex and do not provide all reasonable protections (in many cases, few or no protections) against inadvertent writes. In contrast, the present controller provides several layers of protection against inadvertent writes. The controller also incorporates a write-time monitor, enabling determination of trends in the performance of an EEPROM through all phases of testing. The controller has been designed as an integral subsystem of a system that includes not only the controller and the controlled EEPROM aboard a spacecraft but also computers in a ground control station, relatively simple onboard support circuitry, and an onboard communication subsystem that utilizes the MIL-STD-1553B protocol. (MIL-STD-1553B is a military standard that encompasses a method of communication and electrical-interface requirements for digital electronic subsystems connected to a data bus. MIL-STD- 1553B is commonly used in defense and space applications.) The intent was to both maximize reliability while minimizing the size and complexity of onboard circuitry. In operation, control of the EEPROM is effected via the ground computers, the MIL-STD-1553B communication subsystem, and the onboard support circuitry, all of which, in combination, provide the multiple layers of protection against inadvertent writes. There is no controller software, unlike in many prior EEPROM controllers; software can be a major contributor to unreliability, particularly in fault situations such as the loss of power or brownouts. Protection is also provided by a powermonitoring circuit.

Katz, Richard; Kleyner, Igor

2010-01-01

121

Compact Holographic Data Storage  

NASA Technical Reports Server (NTRS)

NASA's future missions would require massive high-speed onboard data storage capability to Space Science missions. For Space Science, such as the Europa Lander mission, the onboard data storage requirements would be focused on maximizing the spacecraft's ability to survive fault conditions (i.e., no loss in stored science data when spacecraft enters the 'safe mode') and autonomously recover from them during NASA's long-life and deep space missions. This would require the development of non-volatile memory. In order to survive in the stringent environment during space exploration missions, onboard memory requirements would also include: (1) survive a high radiation environment (1 Mrad), (2) operate effectively and efficiently for a very long time (10 years), and (3) sustain at least a billion write cycles. Therefore, memory technologies requirements of NASA's Earth Science and Space Science missions are large capacity, non-volatility, high-transfer rate, high radiation resistance, high storage density, and high power efficiency. JPL, under current sponsorship from NASA Space Science and Earth Science Programs, is developing a high-density, nonvolatile and rad-hard Compact Holographic Data Storage (CHDS) system to enable large-capacity, high-speed, low power consumption, and read/write of data in a space environment. The entire read/write operation will be controlled with electrooptic mechanism without any moving parts. This CHDS will consist of laser diodes, photorefractive crystal, spatial light modulator, photodetector array, and I/O electronic interface. In operation, pages of information would be recorded and retrieved with random access and high-speed. The nonvolatile, rad-hard characteristics of the holographic memory will provide a revolutionary memory technology meeting the high radiation challenge facing the Europa Lander mission. Additional information is contained in the original extended abstract.

Chao, T. H.; Reyes, G. F.; Zhou, H.

2001-01-01

122

Laboratory compaction of cohesionless sands  

E-print Network

A total of 62 cohesiveness sands were tested to rographics. investigate the importance of the water content, grain size distribution, grading of the soil, particle shape, grain crushing during testing and laboratory compaction test method...

Delphia, John Girard

2012-06-07

123

What Is Business's Social Compact?  

ERIC Educational Resources Information Center

Under the "new" social compact, businesses must focus on continuous learning and thus have both an obligation to support teaching and an opportunity to profit from it. Learning organizations must also be teaching organizations. (SK)

Avishai, Bernard

1994-01-01

124

New considerations for compact cyclotrons  

E-print Network

A compact cyclotron built with superconducting magnets could be a transformative solution to many scientific problems facing the defense, medical, and energy industries today. This thesis discusses three potential applications ...

Marshall, Eric S. (Eric Scott)

2012-01-01

125

Compact bilinear operators and commutators  

E-print Network

A notion of compactness in the bilinear setting is explored. Moreover, commutators of bilinear Calderón-Zygmund operators and multiplication by functions in a certain subspace of the space of functions of bounded mean oscillations are shown...

Bé nyi, Á rpá d; Torres, Rodolfo H.

2013-07-01

126

Compaction with automatic jog introduction  

NASA Astrophysics Data System (ADS)

A novel polynomial-time algorithm for compacting a VLSI layout is presented. Compared to previous algorithms, the algorithm promises to produce higher quality output while reducing the need for designer intervention. The performance gain is realized by converting wires into constraints on the positions of the active devices. These constraints can be solved by graph-theoretic techniques to yield optimal positions for chip components. A single-layer router is then used to restore the wires to the layout, using as many as jogs as necessary. An automated compaction procedure is an effective tool for cutting production costs of a VLSI circuit at low cost to the designer, because the yield of fabricated chips is strongly dependent on the total circuit area. Sect 1 is an introduction. Sect 2 states the definitions and theoretical results that underlie the new compaction method. Sect 3 shows how the circuit layout is converted to a data structure appropriate for compaction, and Sect 4 details the body of the compaction algorithm. Sect 5 covers several improvements to the algorithm that should make it run considerably faster. Sect 6 comments on the algorithms of results, and a discussion of the practical value of the compaction algorithm.

Maley, F. M.

1985-10-01

127

Directional Oscillations, Concentrations, and Compensated Compactness via Microlocal Compactness Forms  

NASA Astrophysics Data System (ADS)

This work introduces microlocal compactness forms (MCFs) as a new tool to study oscillations and concentrations in L p -bounded sequences of functions. Decisively, MCFs retain information about the location, value distribution, and direction of oscillations and concentrations, thus extending at the same time the theories of (generalized) Young measures and H-measures. In L p -spaces oscillations and concentrations precisely discriminate between weak and strong compactness, and thus MCFs allow one to quantify the difference in compactness. The definition of MCFs involves a Fourier variable, whereby differential constraints on the functions in the sequence can also be investigated easily—a distinct advantage over Young measure theory. Furthermore, pointwise restrictions are reflected in the MCF as well, paving the way for applications to Tartar's framework of compensated compactness; consequently, we establish a new weak-to-strong compactness theorem in a "geometric" way. After developing several aspects of the abstract theory, we consider three applications; for lamination microstructures, the hierarchy of oscillations is reflected in the MCF. The directional information retained in an MCF is harnessed in the relaxation theory for anisotropic integral functionals. Finally, we indicate how the theory pertains to the study of propagation of singularities in certain systems of PDEs. The proofs combine measure theory, Young measures, and harmonic analysis.

Rindler, Filip

2014-08-01

128

A Compact Polarization Imager  

NASA Technical Reports Server (NTRS)

A new type of image detector has been designed to analyze the polarization of light simultaneously at all picture elements (pixels) in a scene. The Integrated Dual Imaging Detector (IDID) consists of a polarizing beamsplitter bonded to a custom-designed charge-coupled device with signal-analysis circuitry, all integrated on a silicon chip. The IDID should simplify the design and operation of imaging polarimeters and spectroscopic imagers used, for example, in atmospheric and solar research. Other applications include environmental monitoring and robot vision. Innovations in the IDID include two interleaved 512 x 1024 pixel imaging arrays (one for each polarization plane), large dynamic range (well depth of 10(exp 6) electrons per pixel), simultaneous readout and display of both images at 10(exp 6) pixels per second, and on-chip analog signal processing to produce polarization maps in real time. When used with a lithium niobate Fabry-Perot etalon or other color filter that can encode spectral information as polarization, the IDID can reveal tiny differences between simultaneous images at two wavelengths.

Thompson, Karl E.; Rust, David M.; Chen, Hua

1995-01-01

129

Multimedia Compact Disc: Play Therapy Counseling Skills  

Microsoft Academic Search

Multimedia compact discs have become an important part of counseling education. Many educators recognize the value of compact discs in training and methods of instruction. The purpose of this study was to develop an instructional compact disc and to survey counseling students' perceptions of the compact disc. Participants included 71 counseling graduate students from two universities in the southern part

Roxane L. Dufrene; Zoë Tanner

2009-01-01

130

Soil Compaction College of Agricultural Sciences  

E-print Network

Effects of Soil Compaction College of Agricultural Sciences Agricultural Research and Cooperative Extension #12;2 EFFECTS OF SOIL COMPACTION Effects of Soil Compaction INTRODUCTION Soil compaction is the reduction of soil volume due to external factors; this reduction lowers soil productivity and environmental

Kaye, Jason P.

131

Neutrino trapping in braneworld extremely compact stars  

NASA Astrophysics Data System (ADS)

Extremely Compact Stars (ECS) contain trapped null geodesics. When such objects enter the evolution period admitting geodetical motion of neutrinos, certain part of neutrinos produced in their interior will be trapped influencing their neutrino luminosity and thermal evolution. We study neutrino trapping in the braneworld ECS, assuming uniform distribution of neutrino emissivity and massless neutrinos. We give the efficiency of the neutrino trapping effects in the framework of the simple model of the internal spacetime with uniform distribution of energy density, and external spacetime described by the Reissner-Nordström geometry characterized by the braneworld "tidal" parameter b. For b < 0 the external spacetime is of the black-hole type, while for b > 0 the external spacetime can be of both black-hole and naked-singularity type. Then the ECS surface radius R can be located also above the unstable (outer) photon circular orbit. Such basically new types of the spacetimes strongly alter the trapping phenomena as compared to the standard case of b = 0. It is shown that the neutrino trapping effects are slightly lowered by the presence of physically more plausible case of b < 0, as compared to the standard internal Schwarzschild spacetime, while they can be magnified by positive tidal charges if b < 1 and lowered for b > 1. However, potential astrophysical relevance of the trapping phenomena is strongly enhanced for negative tidal charges enabling a significant enlargement of the ECS surface radius to values coherent with recent observations.

Stuchlík, Zden?k; Hladík, Jan; Urbanec, Martin

2011-11-01

132

To Charge or Not to Charge.  

ERIC Educational Resources Information Center

Ways to fund a publications office and the merits of charge-back systems are discussed. Every charge-back system differs. Some offices try to cover costs; others bill for overhead. Some alternatives to charging are described. (MLW)

Hay, Tina M.

1989-01-01

133

The regular-locally-compact coreflection of a stably locally compact locale  

E-print Network

The regular-locally-compact coreflection of a stably locally compact locale locally compact locales and perfect maps as a coref* *lective subcategory of the category of stably locally compact locales and perfect maps, (ii) the category of compact regular locales and continuous maps

Escardó, Martín

134

Charged membranes.  

PubMed

This Teaching Resource provides three animated lessons that describe the storage and utilization of energy across plasma membranes. The "Na,K ATPase" animation explains how these pumps establish the electrochemical gradient that stores energy across plasma membranes. The "ATP synthesizing complexes" animation shows how these complexes transfer energy from the inner mitochondrial membrane to adenosine triphosphate (ATP). The "action potential" lesson explains how charged membranes are used to propagate signals along the axons of neurons. These animations serve as valuable resources for any collegiate-level course that describes these important factors. Courses that might employ them include introductory biology, biochemistry, biophysics, cell biology, pharmacology, and physiology. PMID:23592845

Thatcher, Jack D

2013-01-01

135

Charge Equilibrium  

NASA Astrophysics Data System (ADS)

The mean equililibrium charge of a penetrating ion can be estimated on the basis of Bohr's velocity criterion or Lamb's energy criterion. Qualitative and quantitative results are derived on the basis of the Thomas-Fermi model of the atom, which is discussed explicitly. This includes a brief introduction to the Thomas-Fermi-Dirac model. Special attention is paid to trial function approaches by Lenz and Jensen as well as Brandt and Kitagawa. The chapter also offers a preliminary discussion of the role of the stopping medium, gas-solid differences, and a survey of data compilations.

Sigmund, Peter

136

Spectral responses in granular compaction  

NASA Astrophysics Data System (ADS)

The slow compaction of a tapped granular packing is reminiscent of the low-temperature dynamics glasses. Here, I study the dynamics of granular compaction by means of a volumetric spectroscopy. While the specific packing volume v displays glassy aging and memory effects at low tapping amplitudes ? , the dynamic volumetric susceptibility ?˜v=?v/?? displays minimal glassy effects, and its frequency spectrum gives no indication of a rapidly growing time scale. These features are contrast sharply with that found in the dielectric and magnetic susceptibilities of structural and spin glasses. Instead, ?˜v appears to exhibit the behavior of a dynamic configurational specific heat, such as that obtained from computer simulations of spin-glass models. This suggests that the glassy dynamics of granular compaction is controlled by statistically rare processes that diverge from the typical dynamics of the system. From modifications of the dynamical spectrum by finite system size, I suggest that these glassy processes derive from large-scale collective particle rearrangements.

Zou, Ling-Nan

2010-03-01

137

Compaction Stress in Fine Powders  

SciTech Connect

A vexing feature in granular materials compaction is density extrema interior to a compacted shape. Such inhomogeneities can lead to weaknesses and loss of dimensional control in ceramic parts, unpredictable dissolution of pharmaceuticals, and undesirable stress concentration in load-bearing soil. As an example, the centerline density in a cylindrical compact often does not decrease monotonically from the pressure source but exhibits local maxima and minima. Two lines of thought in the literature predict, respectively, diffusive and wavelike propagation of stress. Here, a general memory function approach has been formulated that unifies these previous treatments as special cases; by analyzing a convenient intermediate case, the telegrapher's equation, one sees that local density maxima arise via semidiffusive stress waves reflecting from the die walls and adding constructively at the centerline.

Hurd, A.J.; Kenkre, V.M.; Pease, E.A.; Scott, J.E.

1999-04-01

138

Compact orthogonal NMR field sensor  

DOEpatents

A Compact Orthogonal Field Sensor for emitting two orthogonal electro-magnetic fields in a common space. More particularly, a replacement inductor for existing NMR (Nuclear Magnetic Resonance) sensors to allow for NMR imaging. The Compact Orthogonal Field Sensor has a conductive coil and a central conductor electrically connected in series. The central conductor is at least partially surrounded by the coil. The coil and central conductor are electrically or electro-magnetically connected to a device having a means for producing or inducing a current through the coil and central conductor. The Compact Orthogonal Field Sensor can be used in NMR imaging applications to determine the position and the associated NMR spectrum of a sample within the electro-magnetic field of the central conductor.

Gerald, II, Rex E. (Brookfield, IL); Rathke, Jerome W. (Homer Glen, IL)

2009-02-03

139

Compact intermediates in RNA folding  

SciTech Connect

Large noncoding RNAs fold into their biologically functional structures via compact yet disordered intermediates, which couple the stable secondary structure of the RNA with the emerging tertiary fold. The specificity of the collapse transition, which coincides with the assembly of helical domains, depends on RNA sequence and counterions. It determines the specificity of the folding pathways and the magnitude of the free energy barriers to the ensuing search for the native conformation. By coupling helix assembly with nascent tertiary interactions, compact folding intermediates in RNA also play a crucial role in ligand binding and RNA-protein recognition.

Woodson, S.A. (JHU)

2011-12-14

140

ULTRA-COMPACT ACCELERATOR TECHNOLOGIES FOR APPLICATION IN NUCLEAR TECHNIQUES  

SciTech Connect

We report on compact accelerator technology development for potential use as a pulsed neutron source quantitative post verifier. The technology is derived from our on-going compact accelerator technology development program for radiography under the US Department of Energy and for a clinic sized compact proton therapy systems under an industry sponsored Cooperative Research and Development Agreement. The accelerator technique relies on the synchronous discharge of a prompt pulse generating stacked transmission line structure with the beam transit. The goal of this technology is to achieve {approx}10 MV/m gradients for 10s of nanoseconds pulses and to {approx}100 MV/m gradients for {approx}1 ns systems. As a post verifier for supplementing existing x-ray equipment, this system can remain in a charged, stand-by state with little or no energy consumption. We detail the progress of our overall component development effort with the multilayer dielectric wall insulators (i.e., the accelerator wall), compact power supply technology, kHz repetition-rate surface flashover ion sources, and the prompt pulse generation system consisting of wide-bandgap switches and high performance dielectric materials.

Sampayan, S; Caporaso, G; Chen, Y; Carazo, V; Falabella, S; Guethlein, G; Guse, S; Harris, J R; Hawkins, S; Holmes, C; Krogh, M; Nelson, S; Paul, A C; Pearson, D; Poole, B; Schmidt, R; Sanders, D; Selenes, K; Sitaraman, S; Sullivan, J; Wang, L; Watson, J

2009-06-11

141

Structural elements in glycoprotein 70 from polytropic Friend mink cell focus-inducing virus and glycoprotein 71 from ecotropic Friend murine leukemia virus, as defined by disulfide-bonding pattern and limited proteolysis.  

PubMed

The disulfide-bonding pattern of glycoprotein 70 (gp70), the surface glycoprotein (SU) encoded by the envelope gene of polytropic Friend milk cell focus-inducing virus, was elucidated and compared with that of glycoprotein 71 (gp71), the corresponding glycoprotein of the ecotropic Friend murine leukemia virus, which had previously been determined (M. Linder, D. Linder, J. Hahnen, H.-H. Schott, and Stirm, Eur. J. Biochem. 203:65-73, 1992). In the carboxy-terminal constant domain, in which these glycoproteins have about 97% sequence homology, the location of the four disulfide bonds was found to be analogous. In the amino-terminal differential domain, with about 37% sequence homology, 8 of the 12 cysteine residues of the ecotropic SU are conserved in the polytropic SU. In this domain, a similar clustering of disulfide bonds was detected, which led to the identification of three distinct disulfide-bonded regions in both glycoproteins. However, because of deletions and sequence deviations, the glycoproteins must have significantly different three-dimensional structures in these regions. Since the receptor-binding functions of both glycoproteins have been attributed to their amino-terminal domains and since each binds to a different receptor, these disulfide-bonded structures are likely candidates for receptor-binding functions. Limited proteolysis of both glycoproteins with various endoproteinases led to the identification of preferential proteolytic sites between disulfide-bonded regions, at the beginning of the hypervariable proline-rich region, and between differential and constant domains, further confirming the structural organization of the folded glycoproteins. PMID:8035513

Linder, M; Wenzel, V; Linder, D; Stirm, S

1994-08-01

142

Structural elements in glycoprotein 70 from polytropic Friend mink cell focus-inducing virus and glycoprotein 71 from ecotropic Friend murine leukemia virus, as defined by disulfide-bonding pattern and limited proteolysis.  

PubMed Central

The disulfide-bonding pattern of glycoprotein 70 (gp70), the surface glycoprotein (SU) encoded by the envelope gene of polytropic Friend milk cell focus-inducing virus, was elucidated and compared with that of glycoprotein 71 (gp71), the corresponding glycoprotein of the ecotropic Friend murine leukemia virus, which had previously been determined (M. Linder, D. Linder, J. Hahnen, H.-H. Schott, and Stirm, Eur. J. Biochem. 203:65-73, 1992). In the carboxy-terminal constant domain, in which these glycoproteins have about 97% sequence homology, the location of the four disulfide bonds was found to be analogous. In the amino-terminal differential domain, with about 37% sequence homology, 8 of the 12 cysteine residues of the ecotropic SU are conserved in the polytropic SU. In this domain, a similar clustering of disulfide bonds was detected, which led to the identification of three distinct disulfide-bonded regions in both glycoproteins. However, because of deletions and sequence deviations, the glycoproteins must have significantly different three-dimensional structures in these regions. Since the receptor-binding functions of both glycoproteins have been attributed to their amino-terminal domains and since each binds to a different receptor, these disulfide-bonded structures are likely candidates for receptor-binding functions. Limited proteolysis of both glycoproteins with various endoproteinases led to the identification of preferential proteolytic sites between disulfide-bonded regions, at the beginning of the hypervariable proline-rich region, and between differential and constant domains, further confirming the structural organization of the folded glycoproteins. Images PMID:8035513

Linder, M; Wenzel, V; Linder, D; Stirm, S

1994-01-01

143

Charged Membranes  

NSDL National Science Digital Library

This Teaching Resource provides three animated lessons that describe the storage and utilization of energy across plasma membranes. The “Na,K ATPase” animation explains how these pumps establish the electrochemical gradient that stores energy across plasma membranes. The “ATP synthesizing complexes” animation shows how these complexes transfer energy from the inner mitochondrial membrane to adenosine triphosphate (ATP). The “action potential” lesson explains how charged membranes are used to propagate signals along the axons of neurons. These animations serve as valuable resources for any collegiate-level course that describes these important factors. Courses that might employ them include introductory biology, biochemistry, biophysics, cell biology, pharmacology, and physiology.

Jack D. Thatcher (Lewisburg;West Virginia School of Osteopathic Medicine REV)

2013-04-16

144

CHARGE Association  

PubMed Central

We present here a case of 17-year-old boy from Kolkata presenting with obesity, bilateral gynecomastia, mental retardation, and hypogonadotrophic hypogonadism. The patient weighed 70 kg and was of 153 cm height. Facial asymmetry (unilateral facial palsy), gynecomastia, decreased pubic and axillary hair, small penis, decreased right testicular volume, non-palpable left testis, and right-sided congenital inguinal hernia was present. The patient also had disc coloboma, convergent squint, microcornea, microphthalmia, pseudohypertelorism, low set ears, short neck, and choanalatresia. He had h/o VSD repaired with patch. Laboratory examination revealed haemoglobin 9.9 mg/dl, urea 24 mg/dl, creatinine 0.68 mg/dl. IGF1 77.80 ng/ml (decreased for age), GH <0.05 ng/ml, testosterone 0.25 ng/ml, FSH-0.95 ?IU/ml, LH 0.60 ?IU/ml. ACTH, 8:00 A.M cortisol, FT3, FT4, TSH, estradiol, DHEA-S, lipid profile, and LFT was within normal limits. Prolactin was elevated at 38.50 ng/ml. The patient's karyotype was 46XY. Echocardiography revealed ventricularseptal defect closed with patch, grade 1 aortic regurgitation, and ejection fraction 67%. Ultrasound testis showed small right testis within scrotal sac and undescended left testis within left inguinal canal. CT scan paranasal sinuses revealed choanalatresia and deviation of nasal septum to the right. Sonomammography revealed bilateral proliferation of fibroglandular elements predominantly in subareoalar region of breasts. MRI of brain and pituitary region revealed markedly atrophic pituitary gland parenchyma with preserved infundibulum and hypothalamus and widened suprasellar cistern. The CHARGE association is an increasingly recognized non-random pattern of congenital anomalies comprising of coloboma, heart defect, choanal atresia, retarded growth and development, genital hypoplasia, ear abnormalities, and/or deafness.[1] These anomalies have a higher probability of occurring together. In this report, we have described a boy with CHARGE association. PMID:23565479

Chakraborty, Semanti; Chakraborty, Jayanta

2012-01-01

145

Properties of dynamically compacted WIPP salt  

SciTech Connect

Dynamic compaction of mine-run salt is being investigated for the Waste Isolation Pilot Plant (WIPP), where compacted salt is being considered for repository sealing applications. One large-scale and two intermediate-scale dynamic compaction demonstrations were conducted. Initial fractional densities of the compacted salt range form 0.85 to 0.90, and permeabilities vary. Dynamically-compacted specimens were further consolidated in the laboratory by application of hydrostatic pressure. Permeability as a function of density was determined, and consolidation microprocesses were studied. Experimental results, in conjunction with modeling results, indicate that the compacted salt will function as a viable seal material.

Brodsky, N.S.; Hansen, F.D. [Sandia National Labs., Albuquerque, NM (United States); Pfeifle, T.W. [RE/SPEC, Inc., Rapid City, SD (United States)

1996-07-01

146

Compaction with automatic jog introduction  

Microsoft Academic Search

A novel polynomial-time algorithm for compacting a VLSI layout is presented. Compared to previous algorithms, the algorithm promises to produce higher quality output while reducing the need for designer intervention. The performance gain is realized by converting wires into constraints on the positions of the active devices. These constraints can be solved by graph-theoretic techniques to yield optimal positions for

F. M. Maley

1985-01-01

147

Compact toroid fueling for ITER  

Microsoft Academic Search

Experimental and theoretical work indicates that deep fueling of ITER may be possible by Compact Toroid (CT) injection. CT velocities sufficient for center fueling of a reactor have been demonstrated in the RACE device. CT injections into the TdeV tokamak have achieved central penetration at 1.4 T, and have increased the particle inventory by more than 30% without disruption. Tests

P. Gierszewski; R. Raman; D. Hwang

1995-01-01

148

Compact toroid fuelling for ITER  

Microsoft Academic Search

Deep fuelling of ITER may be achievable by compact toroid (CT) injection. The advantages of deep fuelling include avoiding edge density limits by fuelling beyond the transport barriers, profile peaking to reach ignition, profile control to improve current drive, low tritium inventory, etc. In this paper, a conceptual design of a CT fueller for ITER is presented. In the proposed

R Raman; P Gierszewski

1998-01-01

149

A Compact Source Projection Lamp  

Microsoft Academic Search

The 250 W mercury vapour compact source lamp is a small, concentrated light source with a high intrinsic brilliancy. It provides radiation high in actinic value and low in heat content; it has a long life, and the arc, which is totally enclosed, operates steadily without attention. The lamp may be used in place of small carbon arcs and tungsten

H K Bourne

1945-01-01

150

Compact heat exchanger design progress  

Microsoft Academic Search

Development of compact plate type heat exchangers for OTEC plants is reviewed. The heat exchangers have horizontal, single pass water flow, vertical downflow condenser, and vertical upflow boiler passages. The design lends itself to many variations in type of water side configuration, and in boiling and condensing surface design. It makes high heat transfer coefficients possible, along with low pressure

J. H. Anderson Jr.; P. B. Pribis

1979-01-01

151

Mesoscale Simulations of Power Compaction  

SciTech Connect

Mesoscale 3D simulations of metal and ceramic powder compaction in shock waves have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating shock compaction of porous well-characterized ductile metal using Steinberg material model. Results of the simulations with handbook values for parameters of solid 2024 aluminum have good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not so well studied as metals, so material model for ceramic (tungsten carbide) has been fitted to shock compression experiments of non-porous samples and further calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powder have been performed and showed good agreement with experimental data. Numerical shock wave profile has same character and thickness as measured with VISAR. Numerical results show reshock states above the single-shock Hugoniot line also observed in experiments. They found that to receive good quantitative agreement with experiment it is essential to perform 3D simulations.

Lomov, I; Fujino, D; Antoun, T; Liu, B

2009-08-06

152

Compact color schlieren optical system  

NASA Astrophysics Data System (ADS)

A compact optical system for use with rainbow schlieren deflectometry is described. Both halves of the optical system consist of well-corrected telescopes whose refractive elements are all from manufacturer's stock catalogs, with the reflective primary being a spherical surface. As a result, the system is relatively easy to construct and meets the requirement of long focal length for quantitative rainbow schlieren measurements.

Buchele, Donald R.; Griffin, Devon W.

1993-08-01

153

Compact color schlieren optical system  

NASA Technical Reports Server (NTRS)

A compact optical system for use with rainbow schlieren deflectometry is described. Both halves of the optical system consist of well-corrected telescopes whose refractive elements are all from manufacturer's stock catalogs, with the reflective primary being a spherical surface. As a result, the system is relatively easy to construct and meets the requirement of long focal length for quantitative rainbow schlieren measurements.

Buchele, Donald R.; Griffin, Devon W.

1993-01-01

154

Compact color schlieren optical system  

Microsoft Academic Search

A compact optical system for use with rainbow schlieren deflectometry is described. Both halves of the optical system consist of well-corrected telescopes whose refractive elements are all from manufacturer's stock catalogs, with the reflective primary being a spherical surface. As a result, the system is relatively easy to construct and meets the requirement of long focal length for quantitative rainbow

Donald R. Buchele; Devon W. Griffin

1993-01-01

155

Charged particle distributions in Jupiter's magnetosphere  

Microsoft Academic Search

In situ data from the Pioneer and Voyager spacecraft, supplemented by earth-based observations and theoretical considerations, are used as the basis for the present quantitative, compact model of the 1 eV-several MeV charged particle distribution in the Jovian magnetosphere. The thermal plasma parameters of convection speed, number density, and characteristic energy, are specified as functions of position for electrons and

Neil Divine; H. B. Garrett

1983-01-01

156

Compaction in the Bushveld Complex  

NASA Astrophysics Data System (ADS)

Compaction in the mush zone of a crystallizing chamber is a model for fractionation, whereby evolved interstitial liquid expelled from the compacting crystal pile is returned to the magma chamber. If compaction was important during crystallization of the Lower and Critical Zones of the Bushveld Complex, certain textural features are expected; and, these features should correlate to position in the section, as well as to the number of mineral phases present. We report on a spectrum of textural data for 30 samples form the Lower and Critical Zones of the Bushveld Complex. Crystal Size Distributions (CSDs) are a semi-log plot of population density against crystal size, and provide information about magmatic processes such as crystal accumulation, removal and aging. Changes to the magmatic system are reflected in the shape of the CSD plot. CSDs of Bushveld rocks show a log-linear trend overturned at smaller grain sizes, a result consistent with both crystal aging, wherein larger grains grow at the expense of small ones in the crystallizing pile, and melt migration, where nucleation is suppressed by the loss of late melt fractions. CSD slope and intercept data vary with stratigraphy. Slopes in the Critical Zone are steeper, indicating less recrystallization and less of a compaction effect. In contrast, slopes in the Lower Zone are shallower, a result consistent with slower cooling and a greater compaction/recrystallization effect. Likewise, lower CSD intercepts are associated with the shallower slopes of the lower zone and vice versa. The extent of foliation is measured as alignment factor (AF), determined by orientation statistics of the major axes of the grains of interest. AF decreases with stratigraphic height and foliation is best developed in the nearly monomineralic harzburgite of the Lower Zone (AF avg=64). At the Lower Zone-Critical Zone transition, plagioclase content increases, decreasing bulk density and thus, the systems ability to accommodate compaction (Upper Critical Zone AF avg=57). There is a positive correlation between the quality of the foliation and mineral aspect ratio, suggesting that recrystallization (crystal aging) demonstrated by CSD plots occurred in a regime of uniaxial stress, wherein selective grain resorption of unfavorably oriented grains and uneven crystal growth results in grains with high aspect ratios. Spatial distribution pattern (SDP) analysis is used to determine the framework structure of spheres in 3-D. Results of R-value analysis (based on nearest neighbor statistics, (Jerram et al., 1996)) are plotted against porosity to compare Bushveld data against fields for touching and non-touching framework structures, and clustered v. ordered crystal distributions. As the Bushveld minerals are not spheres, the applicability of the field boundaries is questionable. Bushveld data form a trend that is coincident with the trend defined either by variable extents of size sorting or by the deformational compaction of spheres. A correlation on a plot of R-value versus aspect ratio clarifies that trend observed on the spatial distribution plot is due to deformational compaction. Phosphorous is a proxy for trapped liquid fraction because it is incompatible in all major phases: it indicates the extent to which late melt has been expelled. Depletion of P in the Lower Zone, where mineral alignment is highest and compaction most efficient, agrees with the hypothesis that compaction was important in redistributing trace elements. Residual porosity calculations based on Y show porosity of 5% in the Lower Zone and 20% in the Upper Critical Zone. R-values plotted against the residual porosity produce a positive trend, relating decreased porosity to grain distribution. Jerram et al., 1996 Contrib. Min. Pet. 125, 60-74.

Boorman, S.; Boudreau, A.

2003-12-01

157

Compact merons and skyrmions in thin chiral magnetic films  

SciTech Connect

A meron is a controversial topological excitation because it carries just one-half of the skyrmion number. A vortex in thin magnetic films has been argued to be a half-skyrmion, i.e., a meron. We present another type of merons, investigating the two-dimensional nonlinear sigma model together with the Dzyaloshinskii-Moriya interaction. Here, the vortex number of a meron is zero. Basic topological excitations are merons and skyrmions. They behave as if they were free particles. A prominent feature is that the topological charge density is strictly confined within compact domains. We propose an analytic approach for these compact excitations, and construct a phase diagram. It is comprised of the helix, meron, skyrmion-crystal, skyrmion-gas, and ferromagnet phases. It captures the essential nature of the experimental data recently performed in chiral magnets such as MnSi and FeCoSi thin films.

Ezawa, Motohiko [Department of Applied Physics, University of Tokyo, Hongo 7-3-1, 113-8656 (Japan)

2011-03-01

158

Compact wavelength division multiplexers and demultiplexers  

E-print Network

Compact wavelength division multiplexers and demultiplexers Revital Shechter, Yaakov Amitai, and Asher A. Friesem Compact devices for wavelength division multiplexing and demultiplexing, believed, including the fact that the recording is done at a single wavelength in the green region. Experimental

Friesem, Asher A.

159

Hydraulic Conductivity of Thirteen Compacted Clays  

Microsoft Academic Search

Abstract--Hydraulic conductivity tests were conducted on thirteen compacted,clayey soils being used for compacted clay liners at landfills throughout the United States. The soils were prepared to various molding water contents and then compacted,and permeated,in the laboratory. Results of the tests show that for all of the soils, zones exist in the compaction plane (i.e., dry unit weight vs. water content)

Craig H. Benson; John M. Trast

1995-01-01

160

Formation and evolution of compact binaries  

Microsoft Academic Search

In this thesis we investigate the formation and evolution of compact binaries. Chapters 2 through 4 deal with the formation of luminous, ultra-compact X-ray binaries in globular clusters. We show that the proposed scenario of magnetic capture produces too few ultra-compact X-ray binaries to explain the observations if we assume strong magnetic braking. Magnetic capture produces no ultra-compact systems at

Marcel Vincent van der Sluijs

2006-01-01

161

Technology of compact fusion-reactor concepts  

SciTech Connect

An identification of future engineering needs of compact, high-power-density approaches to fusion power is presented. After describing a rationale for the compact approach and a number of compact fusion reactors, key technology needs are assessed relative to the similar needs of the conventional tokamak in order to emphasize differences in required technology with respect to the well-documented mainline approaches.

Krakowski, R.A.; Glancy, J.E.; Dabiri, A.E.

1982-01-01

162

The technology of compact fusion reactor concepts  

SciTech Connect

An identification of future engineering needs of compact high-power-density approaches to fusion power is presented. After describing a rationale for the compact approach and a number of compact fusion reactors, key technology needs are assessed relative to the similar needs of the conventional tokamak in order to emphasize differences in required technology with respect to the well-documented mainline approaches.

Krakowski, R.A.; Dabiri, A.E.; Glancy, J.E.

1983-09-01

163

Modified valley fill high power factor electronic ballast for compact fluorescent lamps  

Microsoft Academic Search

A simple, lost cost, high power factor ballast, referred to as the modified valley fill circuit, for compact fluorescent lamps is introduced. This circuit peak charges the valley fill (electrolytic) capacitor from an auxiliary winding on the high frequency ballasting inductor to a fraction of the peak line voltage, where the input power factor is optimized at 0.95. A simple

Mustansir H. Kheraluwala; Sayed Amr El-Hamamsy

1995-01-01

164

Higgsless superconductivity from topological defects in compact BF terms  

E-print Network

We present a new Higgsless model of superconductivity, inspired from anyon superconductivity but P- and T-invariant and generalizable to any dimension. While the original anyon superconductivity mechanism was based on incompressible quantum Hall fluids as average field states, our mechanism involves topological insulators as average field states. In D space dimensions it involves a (D-1)-form fictitious pseudovector gauge field which originates from the condensation of topological defects in compact low-energy effective BF theories. In the average field approximation, the corresponding uniform emergent charge creates a gap for the (D-2)-dimensional branes via the Magnus force, the dual of the Lorentz force. One particular combination of intrinsic and emergent charge fluctuations that leaves the total charge distribution invariant constitutes an isolated gapless mode leading to superfluidity. The remaining massive modes organise themselves into a D-dimensional charged, massive vector. There is no massive Higgs scalar as there is no local order parameter. When electromagnetism is switched on, the photon acquires mass by the topological BF mechanism. Although the charge of the gapless mode (2) and the topological order (4) are the same as those of the standard Higgs model, the two models of superconductivity are clearly different since the origins of the gap, reflected in the high-energy sectors are totally different. In 2D this type of superconductivity is explicitly realized as global superconductivity in Josephson junction arrays. In 3D this model predicts a possible phase transition from topological insulators to Higgsless superconductors.

M. Cristina Diamantini; Carlo A. Trugenberger

2014-08-21

165

Weakly Charged Cationic Nanoparticles Induce DNA Bending and Strand Separation  

SciTech Connect

The understanding of interactions between double stranded (ds) DNA and charged nanoparticles will have a broad bearing on many important applications from drug delivery [ 1 4 ] to DNAtemplated metallization. [ 5 , 6 ] Cationic nanoparticles (NPs) can bind to DNA, a negatively charged molecule, through a combination of electrostatic attraction, groove binding, and intercalation. Such binding events induce changes in the conformation of a DNA strand. In nature, DNA wraps around a cylindrical protein assembly (diameter and height of 6 nm) [ 7 ] with an 220 positive charge, [ 8 ] creating the complex known as chromatin. Wrapping and bending of DNA has also been achieved in the laboratory through the binding of highly charged species such as molecular assemblies, [ 9 , 10 ] cationic dendrimers, [ 11 , 12 ] and nanoparticles. [ 13 15 ] The charge of a nanoparticle plays a crucial role in its ability to induce DNA structural changes. If a nanoparticle has a highly positive surface charge density, the DNA is likely to wrap and bend upon binding to the nanoparticle [ 13 ] (as in the case of chromatin). On the other hand, if a nanoparticle is weakly charged it will not induce dsDNA compaction. [ 9 , 10 , 15 ] Consequently, there is a transition zone from extended to compact DNA conformations which depends on the chemical nature of the nanoparticle and occurs for polycations with charges between 5 and 10. [ 9 ] While the interactions between highly charged NPs and DNA have been extensively studied, the processes that occur within the transition zone are less explored.

Railsback, Justin [North Carolina State University; Singh, Abhishek [North Carolina State University; Pearce, Ryan [North Carolina State University; McKnight, Timothy E [ORNL; Collazo, Ramon [North Carolina State University; Sitar, Zlatko [ORNL; Yingling, Yaroslava [North Carolina State University; Melechko, Anatoli Vasilievich [ORNL

2012-01-01

166

The regular-locally-compact coreflection of a stably locally compact locale  

E-print Network

The regular-locally-compact coreflection of a stably locally compact locale Mart�in H�otzel Escard as the patch frame. We show that the patch construction exhibits (i) the category of regular locally compact locales and perfect maps as a coreflective subcategory of the category of stably locally compact locales

Escardó, Martín

167

Compact lanthanum hexaboride hollow cathode  

NASA Astrophysics Data System (ADS)

A compact lanthanum hexaboride hollow cathode has been developed for space applications where size and mass are important and research and industrial applications where access for implementation might be limited. The cathode design features a refractory metal cathode tube that is easily manufactured, mechanically captured orifice and end plates to eliminate expensive e-beam welding, graphite sleeves to provide a diffusion boundary to protect the LaB6 insert from chemical reactions with the refractory metal tube, and several heater designs to provide long life. The compact LaB6 hollow cathode assembly including emitter, support tube, heater, and keeper electrode is less than 2 cm in diameter and has been fabricated in lengths of 6-15 cm for different applications. The cathode has been operated continuously at discharge currents of 5-60 A in xenon. Slightly larger diameter versions of this design have operated at up to 100 A of discharge current.

Goebel, Dan M.; Watkins, Ronald M.

2010-08-01

168

Compact torus studies: Final report  

SciTech Connect

The compact torus (CT) device has been proposed for use in some applications which are of interest in Laboratory programs in the areas of pulsed power and inertial confinement fusion. These applications involve compression and acceleration of CT plasmas. The RACE (Ring Accelerator Experiment) experimental program at Livermore has been initiated to study these applications. The work reported here involves studies of plasma physics and other aspects of these compact torus applications. The studies conducted identify specific problem areas associated with the CT device and examine these areas in some detail. This report contains studies of three particular problem areas of the CT applications. These three areas are: the general nonlinear properties of the CT as a magnetohydrodynamic (MHD) equilibrium, particle simulation of the compression of the CT, with a focus on the non-MHD effects, and nonlinear RF interaction problems in the CT.

Morse, E.C.

1987-06-01

169

The Atacama Compact Array (ACA)  

NASA Astrophysics Data System (ADS)

For realizing high fidelity of imaging with mosaicing observations, the Atacama Large Millimeter/submillimeter Array (ALMA) consists of a homogeneous array of 12 m antennas (12 m Array) and the Atacama Compact Array (ACA) in order to cover all spatial frequency Fourier components of the brightness distribution of observed sources. The array is located at an altitude site of about 5000m with an operating wavelength range of 0.3 to 3mm. ACA is an array composed of four 12 m dishes [TP (Total Power) Array] and twelve 7 m dishes (7 m Array). The 7 m Array has a very compact configuration to take short-baseline data corresponding to the low spatial frequency Fourier components. The 7 m Array has two configurations extended over 30--50m to avoid shadowing at low elevation. The scientific importances and operation concepts of ACA, and the system design of ACA and its performance are presented in this paper.

Iguchi, Satoru; Morita, Koh-Ichiro; Sugimoto, Masahiro; Vila Vilaró, Baltasar; Saito, Masao; Hasegawa, Tetsuo; Kawabe, Ryohei; Tatematsu, Ken'ichi; Seiichi, Seiichi; Kiuchi, Hitoshi; Okumura, Sachiko K.; Kosugi, George; Inatani, Junji; Takakuwa, Shigehisa; Iono, Daisuke; Kamazaki, Takeshi; Ogasawara, Ryusuke; Ishiguro, Masato

2009-02-01

170

A tandem-based compact dual-energy gamma generator  

SciTech Connect

A dual-energy tandem-type gamma generator has been developed at E. O. Lawrence Berkeley National Laboratory and Sandia National Laboratories. The tandem accelerator geometry allows higher energy nuclear reactions to be reached, thereby allowing more flexible generation of MeV-energy gammas for active interrogation applications. Both positively charged ions and atoms of hydrogen are created from negative ions via a gas stripper. In this paper, we show first results of the working tandem-based gamma generator and that a gas stripper can be utilized in a compact source design. Preliminary results of monoenergetic gamma production are shown.

Persaud, A.; Kwan, J. W.; Leitner, M.; Leung, K.-N.; Ludewigt, B.; Tanaka, N.; Waldron, W.; Wilde, S. [E. O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States); Antolak, A. J.; Morse, D. H.; Raber, T. [Sandia National Laboratories, Livermore, California 94550 (United States)

2010-02-15

171

Closeup View of Compacted Soil  

NASA Technical Reports Server (NTRS)

Soil on Mars can be a bit clumpy, as shown in this image of soil after it was compacted by one of the wheels of NASA's Mars Exploration Rover Spirit. Scientists think the light-colored material may be a global layer of airfall dust. Spirit's microscopic imager took this picture, showing an area approximately 3 centimeters (1.2 inches) square, during the rover's 314th martian day, or sol (Nov. 19, 2004).

2004-01-01

172

Compact color schlieren optical system.  

PubMed

A compact optical system for use with rainbow schlieren deflectometry is described. Both halves of the optical system consist of well-corrected telescopes whose refractive elements are all from manufacturer's stock catalogs, with the reflective primary being a spherical surface. As a result, the system is relatively easy to construct and meets the requirement of long focal length for quantitative rainbow schlieren measurements. PMID:20830072

Buchele, D R; Griffin, D W

1993-08-01

173

Compaction Waves in Granular HMX  

SciTech Connect

Piston driven compaction waves in granular HMX are simulated with a two-dimensional continuum mechanics code in which individual grains are resolved. The constitutive properties of the grains are modeled with a hydrostatic pressure and a simple elastic-plastic model for the shear stress. Parameters are chosen to correspond to inert HMX. For a tightly packed random grain distribution (with initial porosity of 19%) we varied the piston velocity to obtain weak partly compacted waves and stronger fully compacted waves. The average stress and wave speed are compatible with the porous Hugoniot locus for uni- axial strain. However, the heterogeneities give rise to stress concentrations, which lead to localized plastic flow. For weak waves, plastic deformation is the dominant dissipative mechanism and leads to dispersed waves that spread out in time. In addition to dispersion, the granular heterogeneities give rise to subgrain spatial variation in the thermodynamic variables. The peaks in the temperature fluctuations, known as hot spots, are in the range such that they are the critical factor for initiation sensitivity.

E. Kober; R. Menikoff

1999-01-01

174

Thixoforming of Stellite Powder Compacts  

NASA Astrophysics Data System (ADS)

Thixoforming involves processing metallic alloys in the semi-solid state. The process requires the microstructure to be spheroidal when part-solid and part-liquid i.e. to consist of solid spheroids surrounded by liquid. The aim of this work was to investigate whether powder compacts can be used as feedstock for thixoforming and whether the consolidating pressure in the thixoformer can be used to remove porosity from the compact. The powder compacts were made from stellite 6 and stellite 21 alloys, cobalt-based alloys widely used for e.g. manufacturing prostheses. Isothermal heat treatments of small samples in the consolidated state showed the optimum thixoforming temperature to be in the range 1340°C-1350°C for both materials. The alloys were thixoformed into graphite dies and flowed easily to fill the die. Porosity in the thixoformed components was lower than in the starting material. Hardness values at various positions along the radius of the thixoformed demonstrator component were above the specification for both alloys.

Hogg, S. C.; Atkinson, H. V.; Kapranos, P.

2007-04-01

175

Compact noninvasive electron bunch-length monitor  

A compact rf cavity was constructed that simultaneously resonates at many harmonic modes when excited by a repetitive bunched electron beam passing through its bore. The excitation of these modes provides a Fourier description of the temporal characteristics of the bunch train. The cavity was used to noninvasively characterize electron bunches produced from thin and thick GaAs photocathodes inside a DC high voltage photogun illuminated with 37 ps (full width half maximum, FWHM) laser pulses at repetition rates near 1500 MHz, at average beam current from 5 to 500????A , and at beam energy from 75 to 195 keV. The cavity bunch-length monitor could detect electron bunches as short as 57 ps (FWHM) when connected directly to a sampling oscilloscope, and could clearly distinguish bunches with varying degrees of space-charge induced growth and with different tail signatures. Efforts are under way to detect shorter bunches by designing cavities with increased bandwidth. This demonstration lends credibility to the idea that these cavities could also be used for other applications, including bunching and shaping, when driven with external rf.

Roberts, B.; Mammei, R. R.; Poelker, M.; McCarter, J. L.

2012-12-01

176

Analysis of compact and sealed RPCs feasibility  

NASA Astrophysics Data System (ADS)

In this article, the feasibility of developing compact and portable float glass sealed Resistive Plate Chambers, sRPCs, is analyzed. For this purpose, several small (80 cm2) sealed chambers have been constructed using inexpensive materials like windows float glass, copper tape and nylon fishing line. For the sake of simplicity, during this first development stage, only R134a has been used as ionizing gas. In order to distinguish gas leakage from internal gas degradation, a couple of sRPCs were tested inside a box with flowing gas: one with R134a and another with N2. Prompt charge, signal rising slope and operational current were used to assess chambers performance degradation during a two-week period. Regarding these variables, small leakages were spotted as the main reason for the performance degradation observed after about one week of steady operation at the sRPC working in N2 environment. The sRPC working in an R134a environment did not show any significative degradation during the whole test. A discussion on merits and limitations of the proposed design is provided.

Morales, M.; Rodríguez-Sánchez, J. L.; Garzón, J. A.

2013-03-01

177

Electron Strippers for Compact Neutron Generators  

NASA Astrophysics Data System (ADS)

The next generation of compact tandem-type DD or DT neutron generators requires a robust electron stripper with high charge exchange efficiency. In this study, stripping foils of various types were tested, and the H- to H+ conversion efficiency, endurance to the heat load, and durability were investigated in terms of suitability in the tandem-type neutron generator. In the experiments, a H- beam was accelerated to about 180 keV, passes through a stripping foil, and produces a mixed beam of H-, H0, and H+. These ions were separated by an electric field, and detected by a movable Faraday cup to determine the conversion efficiency. The experimental results using thin foils of diamond-like carbon, gold, and carbon nano-tubes revealed issues on the robustness. As a new concept, a H- beam was injected onto a metal surface with an oblique angle, and reflected H+ ions are detected. It was found that the conversion efficiency, H+ fraction in the reflected particles, depends on the surface condition, with the maximum value of about 90%.

Terai, K.; Tanaka, N.; Kisaki, M.; Tsugawa, K.; Okamoto, A.; Kitajima, S.; Sasao, M.; Takeno, T.; Antolak, A. J.; Leung, K. N.; Wada, M.

2011-09-01

178

A compact 1 MV multi-element AMS system  

NASA Astrophysics Data System (ADS)

HVE has designed and built a compact 1 MV multi-element AMS system with a footprint of 3.8 m × 6.3 m. The system is primarily designed for the analysis of light elements like beryllium, carbon and aluminium, but it also supports the measurement of heavy ions like iodine and plutonium. The analysis of 14C is done using the charge state 1. For this, the accelerator terminal is designed for high stripper gas thickness to efficiently destroy the interfering molecules like 13CH and 12CH 2. For the analysis of 10Be, suppression of the isobaric 10B is achieved using an absorber foil that can be inserted in front of the electrostatic analyser. The analysis of 26Al can be done using charge-state 1 or 3. The rare isotopes are identified in a dual-anode high-resolution detector and a two-dimensional data acquisition system.

Klein, M. G.; Mous, D. J. W.; Gottdang, A.

2006-08-01

179

Chaotic Accretion in a Non-Stationary Electromagnetic Field of a Slowly Rotating Compact Star  

E-print Network

We investigate charge accretion in vicinity of a slowly rotating compact star with a non-stationary electromagnetic field. Exact solutions to the general relativistic Maxwell equations are obtained for a star formed of a highly degenerate plasma with a gravitational field given by the linearized Kerr metric. These solutions are used to formulate and then to study numerically the equations of motion for a charged particle in star's vicinity using the gravitoelectromagnetic force law. The analysis shows that close to the star charge accretion does not always remain ordered. It is found that the magnetic field plays the dominant role in the onset of chaos near the star's surface.

Babur M. Mirza

2007-02-28

180

Compact Video Microscope Imaging System Implemented in Colloid Studies  

NASA Technical Reports Server (NTRS)

Long description Photographs showing fiber-optic light source, microscope and charge-coupled discharge (CCD) camera head connected to camera body, CCD camera body feeding data to image acquisition board in PC, and Cartesian robot controlled via PC board. The Compact Microscope Imaging System (CMIS) is a diagnostic tool with intelligent controls for use in space, industrial, medical, and security applications. CMIS can be used in situ with a minimum amount of user intervention. This system can scan, find areas of interest in, focus on, and acquire images automatically. Many multiple-cell experiments require microscopy for in situ observations; this is feasible only with compact microscope systems. CMIS is a miniature machine vision system that combines intelligent image processing with remote control. The software also has a user-friendly interface, which can be used independently of the hardware for further post-experiment analysis. CMIS has been successfully developed in the SML Laboratory at the NASA Glenn Research Center and adapted for use for colloid studies and is available for telescience experiments. The main innovations this year are an improved interface, optimized algorithms, and the ability to control conventional full-sized microscopes in addition to compact microscopes. The CMIS software-hardware interface is being integrated into our SML Analysis package, which will be a robust general-purpose image-processing package that can handle over 100 space and industrial applications.

McDowell, Mark

2002-01-01

181

Isometric Immersions and Compensated Compactness  

NASA Astrophysics Data System (ADS)

A fundamental problem in differential geometry is to characterize intrinsic metrics on a two-dimensional Riemannian manifold {{mathcal M}^2} which can be realized as isometric immersions into {mathbb{R}^3}. This problem can be formulated as initial and/or boundary value problems for a system of nonlinear partial differential equations of mixed elliptic-hyperbolic type whose mathematical theory is largely incomplete. In this paper, we develop a general approach, which combines a fluid dynamic formulation of balance laws for the Gauss-Codazzi system with a compensated compactness framework, to deal with the initial and/or boundary value problems for isometric immersions in {mathbb{R}^3}. The compensated compactness framework formed here is a natural formulation to ensure the weak continuity of the Gauss-Codazzi system for approximate solutions, which yields the isometric realization of two-dimensional surfaces in {mathbb{R}^3}. As a first application of this approach, we study the isometric immersion problem for two-dimensional Riemannian manifolds with strictly negative Gauss curvature. We prove that there exists a C 1, 1 isometric immersion of the two-dimensional manifold in {mathbb{R}^3} satisfying our prescribed initial conditions. To achieve this, we introduce a vanishing viscosity method depending on the features of initial value problems for isometric immersions and present a technique to make the a priori estimates including the L ? control and H -1-compactness for the viscous approximate solutions. This yields the weak convergence of the vanishing viscosity approximate solutions and the weak continuity of the Gauss-Codazzi system for the approximate solutions, hence the existence of an isometric immersion of the manifold into {mathbb{R}^3} satisfying our initial conditions. The theory is applied to a specific example of the metric associated with the catenoid.

Chen, Gui-Qiang; Slemrod, Marshall; Wang, Dehua

2010-03-01

182

Gravitational Waves from Compact Objects  

NASA Astrophysics Data System (ADS)

This thesis addresses problems in the generation and detection of gravitational waves from two types of sources: inspiraling compact binaries and rapidly rotating young neutron stars. Chapters 2 and 3 estimate the computational costs of a basic matched filtering strategy to search for inspiraling compact binaries. Chapter 2 (written in 1995) sets up the machinery for calculating costs and makes a rough estimate based on the waveforms and noise spectra available at the time. It also systematizes previously published methods of choosing the filters. Chapter 3 (written with B. S. Sathyaprakash in 1998) fine-tunes the machinery and updates the estimates of Chapter 2 using more current waveforms and noise spectra. Chapter 4 (written with Hideyuki Tagoshi and Akira Ohashi) concerns the post-Newtonian generation of gravitational waveforms from inspiraling compact binaries whose component objects spin about their own axes. It lays out a method of calculating post-Newtonian spin effects and calculates the lowest-order such effect not previously known (the second-post-Newtonian spin-orbit contribution to the waveforms in the absence of precession). Chapters 5 and 6 concern the Chandrasekhar-Friedman-Schutz (CFS) gravitational radiation instability as it applies to the r-modes of rapidly rotating young neutron stars. Chapter 5 (written with Lee Lindblom and Sharon M. Morsink) computes the viscous damping and gravitational radiation timescales of the r-modes and shows that viscosity does not suppress the CFS instability in hot young neutron stars. Chapter 6 (written with Lee Lindblom, Curt Cutler, Bernard F. Schutz, Alberto Vecchio, and Nils Andersson) computes approximate gravitational waveforms from young neutron stars spinning down due to the r-mode instability and estimates that these gravitational waves can be detected by the 'enhanced' LIGO interferometers if a suitable data analysis strategy is developed.

Owen, Benjamin James

183

Compact plasmonic variable optical attenuator.  

PubMed

We demonstrate plasmonic nanowire-based thermo-optic variable optical attenuators operating in the 1525-1625 nm wavelength range. The devices have a footprint as low as 1 mm, extinction ratio exceeding 40 dB, driving voltage below 3 V, and full modulation bandwidth of 1 kHz. The polarization dependent loss is shown to be critically dependent on the nanowire geometry but devices with polarization-dependent loss as low as +/-2.5 dB PDL over most of the attenuation range have been fabricated. We propose an even more compact device design to reduce insertion loss to approximately 1 dB. PMID:18825193

Leosson, Kristjan; Rosenzveig, Tiberiu; Hermannsson, Petur G; Boltasseva, Alexandra

2008-09-29

184

The Cooling of Compact Stars  

E-print Network

The cooling of a compact star depends very sensitively on the state of dense matter at supranuclear densities, which essentially controls the neutrino emission, as well as on the structure of the stellar outer layers which control the photon emission. Open issues concern the hyperon population, the presence of meson condensates, superfluidity and superconductivity, and the transition of confined hadronic matter to quark matter. This paper describes these issues and presents cooling calculations based on a broad collection of equations of state for neutron star matter and strange matter. These results are tested against the body of observed cooling data.

Dany Page; Ulrich Geppert; Fridolin Weber

2005-08-01

185

Compact Radiometers Expand Climate Knowledge  

NASA Technical Reports Server (NTRS)

To gain a better understanding of Earth's water, energy, and carbon cycles, NASA plans to embark on the Soil Moisture Active and Passive mission in 2015. To prepare, Goddard Space Flight Center provided Small Business Innovation Research (SBIR) funding to ProSensing Inc., of Amherst, Massachusetts, to develop a compact ultrastable radiometer for sea surface salinity and soil moisture mapping. ProSensing incorporated small, low-cost, high-performance elements into just a few circuit boards and now offers two lightweight radiometers commercially. Government research agencies, university research groups, and large corporations around the world are using the devices for mapping soil moisture, ocean salinity, and wind speed.

2010-01-01

186

Compact broadband planar orthomode transducer  

E-print Network

We present the design and test results of a compact C-band orthomode transducer which comprises four rectangular probes orthogonally arranged in a circular waveguide, designed to work in the WG13 band. Measurements of the system in the frequency range 4.64 GHz to 7.05 GHz agree very well with simulation results and show a cross-polarisation level below -58 dB, a return loss of about -20 dB, and an insertion loss difference of less than 0.18 dB between the orthogonal polarisation modes across the full waveguide band.

P. K. Grimes; O. G. King; G. Yassin; M. E. Jones

2007-09-12

187

Two Piece Compaction Die Design  

SciTech Connect

Compaction dies used to create europium oxide and tantalum control plates were modeled using ANSYS 11.0. Two-piece designs were considered in order to make the dies easier to assemble than the five-piece dies that were previously used. The two areas of concern were the stresses at the interior corner of the die cavity and the distortion of the cavity wall due to the interference fit between the two pieces and the pressure exerted on the die during the compaction process. A successful die design would have stresses less than the yield stress of the material and a maximum wall distortion on the order of 0.0001 in. Design factors that were investigated include the inner corner radius, the value of the interference fit, the compaction force, the size of the cavity, and the outer radius and geometry of the outer ring. The results show that for the europium oxide die, a 0.01 in. diameter wire can be used to create the cavity, leading to a 0.0055 in. radius corner, if the radial interference fit is 0.003 in. For the tantalum die, the same wire can be used with a radial interference fit of 0.001 in. Also, for the europium oxide die with a 0.003 in. interference fit, it is possible to use a wire with a diameter of 0.006 in. for the wire burning process. Adding a 10% safety factor to the compaction force tends to lead to conservative estimates of the stresses but not for the wall distortion. However, when the 10% safety factor is removed, the wall distortion is not affected enough to discard the design. Finally, regarding the europium oxide die, when the cavity walls are increased by 0.002 in. per side or the outer ring is made to the same geometry as the tantalum die, all the stresses and wall distortions are within the desired range. Thus, the recommendation is to use a 0.006 in. diameter wire and a 0.003 in. interference fit for the europium oxide die and a 0.01 in. diameter wire and a 0.001 in. interference fit for the tantalum die. The dies can also be made to have the same outer geometry if desired.

Coffey, Ethan N [ORNL

2010-03-01

188

Simplified compact containment BWR plant  

SciTech Connect

The reactor concept considered in this paper has a small power output, a compact containment and a simplified BWR configuration with comprehensive safety features. The Compact Containment Boiling Water Reactor (CCR), which is being developed with matured BWR technologies together with innovative systems/components, is expected to prove attractive in the world energy markets due to its flexibility in regard to both energy demands and site conditions, its high potential for reducing investment risk and its safety features facilitating public acceptance. The flexibility is achieved by CCR's small power output of 300 MWe class and capability of long operating cycle (refueling intervals). CCR is expected to be attractive from view point of investment due to its simplification/innovation in design such as natural circulation core cooling with the bottom located short core, internal upper entry control rod drives (CRDs) with ring-type dryers and simplified ECCS system with high pressure containment concept. The natural circulation core eliminates recirculation pumps and the maintenance of such pumps. The internal upper entry CRDs reduce the height of the reactor vessel (RPV) and consequently reduce the height of the primary containment vessel (PCV). The safety features mainly consist of large water inventory above the core without large penetration below the top of the core, passive cooling system by isolation condenser (IC), passive auto catalytic recombiner and in-vessel retention (IVR) capability. The large inventory increases the system response time in the case of design-base accidents, including loss of coolant accidents. The IC suppresses PCV pressure by steam condensation without any AC power. The recombiner decreases hydrogen concentration in the PCV in the case of a severe accident. Cooling the molten core inside the RPV if the core should be damaged by loss of core coolability could attain the IVR. The feasibility of CCR safety system has been confirmed by LOCA analysis. The Compact Containment Boiling Water Reactor (CCR) has the possibility realizing both an economical and a safe small reactor through application of a simplified system and compact PCV. (authors)

Heki, H.; Nakamaru, M.; Tsutagawa, M.; Hiraiwa, K. [System Design and Engineering Department, Toshiba Corporation, 8, Shinsugita-cho, Isogo-ku, Yokohama 235-85 (Japan); Arai, K. [Power and Industrial Systems Research and Development Center, Toshiba Corporation, 4-1 Ukishima-cho, Kawasaki-ku, Kawasaki 210-0862 (Japan); Hida, T. [The Japan Atomic Power Company, 1-1, Kandamitoshiro-cho, Chiyoda-ku 101-0053 (Japan)

2004-07-01

189

Shock compaction of molybdenum powder  

NASA Technical Reports Server (NTRS)

Shock recovery experiments which were carried out in the 9 to 12 GPa range on 1.4 distension Mo and appear adequate to compact to full density ( 45 (SIGMA)m) powders were examined. The stress levels, however, are below those calculated to be from 100 to approx. 22 GPa which a frictional heating model predicts are required to consolidate approx. 10 to 50 (SIGMA)m particles. The model predicts that powders that have a distension of m=1.6 shock pressures of 14 to 72 GPa are required to consolidate Mo powders in the 50 to 10 (SIGMA)m range.

Ahrens, T. J.; Kostka, D.; Vreeland, T., Jr.; Schwarz, R. B.; Kasiraj, P.

1983-01-01

190

Intense Pulsed Neutron Emission from a Compact Pyroelectric Driven Accelerator  

SciTech Connect

Intense pulsed D-D neutron emission with rates >10{sup 10} n/s during the pulse, pulse widths of {approx}100's ns, and neutron yields >10 k per pulse are demonstrated in a compact pyroelectric accelerator. The accelerator consists of a small pyroelectric LiTaO{sub 3} crystal which provides the accelerating voltage and an independent compact spark plasma ion source. The crystal voltage versus temperature is characterized and compare well with theory. Results show neutron output per pulse that scales with voltage as V{approx}1.7. These neutron yields match a simple model of the system at low voltages but are lower than predicted at higher voltages due to charge losses not accounted for in the model. Interpretation of the data against modeling provides understanding of the accelerator and in general pyroelectric LiTaO{sub 3} crystals operated as charge limited negative high voltage targets. The findings overall serve as the proof-of-principle and basis for pyroelectric neutron generators that can be pulsed, giving peak neutron rates orders of magnitude greater than previous work, and notably increase the potential applications of pyroelectric based neutron generators.

Tang, V; Meyer, G; Falabella, S; Guethlein, G; Sampayan, S; Kerr, P; Rusnak, B; Morse, J

2008-10-08

191

Gravitational collapse of charged scalar fields  

NASA Astrophysics Data System (ADS)

In order to study the gravitational collapse of charged matter we analyze the simple model of an self-gravitating massless scalar field coupled to the electromagnetic field in spherical symmetry. The evolution equations for the Maxwell-Klein-Gordon sector are derived in the 3+1 formalism, and coupled to gravity by means of the stress-energy tensor of these fields. To solve consistently the full system we employ a generalized Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation of General Relativity that is adapted to spherical symmetry. We consider two sets of initial data that represent a time symmetric spherical thick shell of charged scalar field, and differ by the fact that one set has zero global electrical charge while the other has non-zero global charge. For compact enough initial shells we find that the configuration doesn't disperse and approaches a final state corresponding to a sub-extremal Reissner-N\\"ordstrom black hole with $|Q|charge of the scalar field $q$ we find that the final black hole tends to become more and more neutral. Our results support the cosmic censorship conjecture for the case of charged matter.

Torres, Jose M.; Alcubierre, Miguel

2014-09-01

192

Dense and Homogeneous Compaction of Fine Ceramic and Metallic Powders: High-Speed Centrifugal Compaction Process  

SciTech Connect

High-Speed Centrifugal Compaction Process (HCP) is a variation of colloidal compacting method, in which the powders sediment under huge centrifugal force. Compacting mechanism of HCP differs from conventional colloidal process such as slip casting. The unique compacting mechanism of HCP leads to a number of characteristics such as a higher compacting speed, wide applicability for net shape formation, flawless microstructure of the green compacts, etc. However, HCP also has several deteriorative characteristics that must be overcome to fully realize this process' full potential.

Suzuki, Hiroyuki Y. [Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiayma, Higashi-Hiroshima, Hiroshima, 739-8527 (Japan)

2008-02-15

193

Compact pulse forming line using barium titanate ceramic material  

NASA Astrophysics Data System (ADS)

Ceramic material has very high relative permittivity, so compact pulse forming line can be made using these materials. Barium titanate (BaTiO3) has a relative permittivity of 1200 so it is used for making compact pulse forming line (PFL). Barium titanate also has piezoelectric effects so it cracks during high voltages discharges due to stresses developed in it. Barium titanate is mixed with rubber which absorbs the piezoelectric stresses when the PFL is charged and regain its original shape after the discharge. A composite mixture of barium titanate with the neoprene rubber is prepared. The relative permittivity of the composite mixture is measured to be 85. A coaxial pulse forming line of inner diameter 120 mm, outer diameter 240 mm, and length 350 mm is made and the composite mixture of barium titanate and neoprene rubber is filled between the inner and outer cylinders. The PFL is charged up to 120 kV and discharged into 5 ? load. The voltage pulse of 70 kV, 21 ns is measured across the load. The conventional PFL is made up of oil or plastics dielectrics with the relative permittivity of 2-10 [D. R. Linde, CRC Handbook of Chemistry and Physics, 90th ed. (CRC, 2009); Xia et al., Rev. Sci. Instrum. 79, 086113 (2008); Yang et al., Rev. Sci. Instrum. 81, 43303 (2010)], which increases the length of PFL. We have reported the compactness in length achieved due to increase in relative permittivity of composite mixture by adding barium titanate in neoprene rubber.

Kumar Sharma, Surender; Deb, P.; Shukla, R.; Prabaharan, T.; Shyam, A.

2011-11-01

194

Characteristics of solid-target charge-exchange analyzers for energetic ion diagnostics on tokamaks  

SciTech Connect

Compact electrostatic charge-exchange analyzers have been constructed for installation in areas of high magnetic fields and restricted access near tokamak fusion devices. The analyzers employed carbon stripping foils, and have been calibrated for proton energies between 1 and 70 keV. They have been successfully used to study charge-exchange losses in auxiliary-heated tokamak plasmas.

Beiersdorfer, P.; Roquemore, A.L.; Kaita, R.

1987-05-01

195

Compacted carbon for electrochemical cells  

DOEpatents

This invention provides compacted carbon that is useful in the electrode of an alkali metal/carbon electrochemical cell of improved capacity selected from the group consisting of: (a) coke having the following properties: (i) an x-ray density of at least 2.00 grams per cubic centimeters, (ii) a closed porosity of no greater than 5%, and (iii) an open porosity of no greater than 47%; and (b) graphite having the following properties: (i) an x-ray density of at least 2.20 grams per cubic centimeters, (ii) a closed porosity of no greater than 5%, and (iii) an open porosity of no greater than 25%. This invention also relates to an electrode for an alkali metal/carbon electrochemical cell comprising compacted carbon as described above and a binder. This invention further provides an alkali metal/carbon electrochemical cell comprising: (a) an electrode as described above, (b) a non-aqueous electrolytic solution comprising an organic aprotic solvent and an electrolytically conductive salt and an alkali metal, and (c) a counterelectrode.

Greinke, Ronald Alfred (Medina, OH); Lewis, Irwin Charles (Strongsville, OH)

1997-01-01

196

Hydrostatic compaction of Microtherm HT.  

SciTech Connect

Two samples of jacketed Microtherm{reg_sign}HT were hydrostatically pressurized to maximum pressures of 29,000 psi to evaluate both pressure-volume response and change in bulk modulus as a function of density. During testing, each of the two samples exhibited large irreversible compactive volumetric strains with only small increases in pressure; however at volumetric strains of approximately 50%, the Microtherm{reg_sign}HT stiffened noticeably at ever increasing rates. At the maximum pressure of 29,000 psi, the volumetric strains for both samples were approximately 70%. Bulk modulus, as determined from hydrostatic unload/reload loops, increased by more than two-orders of magnitude (from about 4500 psi to over 500,000 psi) from an initial material density of {approx}0.3 g/cc to a final density of {approx}1.1 g/cc. An empirical fit to the density vs. bulk modulus data is K = 492769{rho}{sup 4.6548}, where K is the bulk modulus in psi, and {rho} is the material density in g/cm{sup 3}. The porosity decreased from 88% to {approx}20% indicating that much higher pressures would be required to compact the material fully.

Broome, Scott Thomas; Bauer, Stephen J.

2010-09-01

197

Incompletely compacted equilibrated ordinary chondrites  

SciTech Connect

We document the size distributions and locations of voids present within five highly porous equilibrated ordinary chondrites using high-resolution synchrotron X-ray microtomography ({mu}CT) and helium pycnometry. We found total porosities ranging from {approx}10 to 20% within these chondrites, and with {mu}CT we show that up to 64% of the void space is located within intergranular voids within the rock. Given the low (S1-S2) shock stages of the samples and the large voids between mineral grains, we conclude that these samples experienced unusually low amounts of compaction and shock loading throughout their entire post accretionary history. With Fe metal and FeS metal abundances and grain size distributions, we show that these chondrites formed naturally with greater than average porosities prior to parent body metamorphism. These materials were not 'fluffed' on their parent body by impact-related regolith gardening or events caused by seismic vibrations. Samples of all three chemical types of ordinary chondrites (LL, L, H) are represented in this study and we conclude that incomplete compaction is common within the asteroid belt.

Sasso, M.R.; Macke, R.J.; Boesenberg, J.S.; Britt, D.T.; Rovers, M.L.; Ebel, D.S.; Friedrich, J.M.; (Fordham)

2010-01-22

198

Method for preparing porous metal hydride compacts  

DOEpatents

A method for preparing porous metallic-matrix hydride compacts which can be repeatedly hydrided and dehydrided without disintegration. A mixture of a finely divided metal hydride and a finely divided matrix metal is contacted with a poison which prevents the metal hydride from dehydriding at room temperature and atmospheric pressure. The mixture of matrix metal and poisoned metal hydride is then compacted under pressure at room temperature to form porous metallic-matrix hydride compacts.

Ron, Moshe (Haifa, IL); Gruen, Dieter M. (Downers Grove, IL); Mendelsohn, Marshall H. (Woodridge, IL); Sheft, Irving (Oak Park, IL)

1981-01-01

199

Method for preparing porous metal hydride compacts  

DOEpatents

A method for preparing porous metallic-matrix hydride compacts which can be repeatedly hydrided and dehydrided without disintegration. A mixture of a finely divided metal hydride and a finely divided matrix metal is contacted with a poison which prevents the metal hydride from dehydriding at room temperature and atmospheric pressure. The mixture of matrix metal and poisoned metal hydride is then compacted under pressure at room temperature to form porous metallic-matrix hydride compacts.

Ron, M.; Gruen, D.M.; Mendelsohn, M.H.; Sheft, I.

1980-01-21

200

Compact approach to fusion power reactors  

SciTech Connect

The potential of the Reversed-Field Pinch (RFP) for development into an efficient, compact, copper-coil fusion reactor has been quantified by comprehensive parametric tradeoff studies. These compact systems promise to be competitive in size, power density, and cost to alternative energy sources. Conceptual engineering designs that largely substantiate these promising results have since been completed. This 1000-MWe(net) design is described along with a detailed rationale and physics/technology assessment for the compact approach to fusion.

Hagenson, R.L.; Krakowski, R.A.; Bathke, C.G.; Miller, R.L.

1984-01-01

201

Compact Solid State Cooling Systems: Compact MEMS Electrocaloric Module  

SciTech Connect

BEETIT Project: UCLA is developing a novel solid-state cooling technology to translate a recent scientific discovery of the so-called giant electrocaloric effect into commercially viable compact cooling systems. Traditional air conditioners use noisy, vapor compression systems that include a polluting liquid refrigerant to circulate within the air conditioner, absorb heat, and pump the heat out into the environment. Electrocaloric materials achieve the same result by heating up when placed within an electric field and cooling down when removed—effectively pumping heat out from a cooler to warmer environment. This electrocaloric-based solid state cooling system is quiet and does not use liquid refrigerants. The innovation includes developing nano-structured materials and reliable interfaces for heat exchange. With these innovations and advances in micro/nano-scale manufacturing technologies pioneered by semiconductor companies, UCLA is aiming to extend the performance/reliability of the cooling module.

None

2010-10-01

202

Charge and Carry  

NSDL National Science Digital Library

In this activity about electricity, learners produce a spark that they can feel, see, and hear. Learners rub a Styrofoam plate with wool to give it an electric charge. Then, they use the charged Styrofoam to charge an aluminum pie pan. Essentially, learners build an electrophorus (Greek for "charge carrier"). This resource also contains instructions on how to build a large charge carrier called a "Leyden Jar" using a plastic film can.

Exploratorium, The

2012-06-26

203

Charged Q-balls and boson stars and dynamics of charged test particles  

E-print Network

We construct electrically charged Q-balls and boson stars in a model with a scalar self-interaction potential resulting from gauge mediated supersymmetry breaking. We discuss the properties of these solutions in detail and emphasize the differences to the uncharged case. We observe that Q-balls can only be constructed up to a maximal value of the charge of the scalar field, while for boson stars the interplay between the attractive gravitational force and the repulsive electromagnetic force determines their behaviour. We find that the vacuum is stable with respect to pair production in the presence of our charged boson stars. We also study the motion of charged, massive test particles in the space-time of boson stars. We find that in contrast to charged black holes the motion of charged test particles in charged boson star space-times is planar, but that the presence of the scalar field plays a crucial role for the qualitative features of the trajectories. Applications of this test particle motion can be made in the study of extreme-mass ratio inspirals (EMRIs) as well as astrophysical plasmas relevant e.g. in the formation of accretion discs and polar jets of compact objects.

Yves Brihaye; Valeria Diemer; Betti Hartmann

2014-02-05

204

Uncertainty Principles for Compact Groups  

E-print Network

We establish an operator-theoretic uncertainty principle over arbitrary compact groups, generalizing several previous results. As a consequence, we show that if f is in L^2(G), then the product of the measures of the supports of f and its Fourier transform ^f is at least 1; here, the dual measure is given by the sum, over all irreducible representations V, of d_V rank(^f(V)). For finite groups, our principle implies the following: if P and R are projection operators on the group algebra C[G] such that P commutes with projection onto each group element, and R commutes with left multiplication, then the squared operator norm of PR is at most rank(P)rank(R)/|G|.

Gorjan Alagic; Alexander Russell

2006-08-28

205

Compact quantum cascade laser transmitter  

NASA Astrophysics Data System (ADS)

In this paper we present design considerations, thermal and optical modeling results, and device performance for a ruggedized, compact laser transmitter that utilizes a room temperature quantum cascade (QC) laser source. The QC laser transmitter is intended for portable mid-infrared spectroscopy applications, where the 3 to 5 ?m and 8 to 12 ?m atmospheric transmission window is relatively free of water vapor interference and where the molecular rotational vibration absorption features can be used to detect and uniquely identify chemical compounds of interest. Initial QC laser-based sensor development efforts were constrained by the complications of cryogenic operation. However, improvements in both QC laser designs and fabrication processes have provided room-temperature devices that now enable significant miniaturization and integration potential for national security, environmental monitoring, atmospheric science, and industrial safety applications.

Anheier, Norman C., Jr.; Hatchell, Brian K.; Gervais, Kevin L.; Wojcik, Michael D.; Krishnaswami, Kannan; Bernacki, Bruce E.

2009-05-01

206

Compact Microwave Fourier Spectrum Analyzer  

NASA Technical Reports Server (NTRS)

A compact photonic microwave Fourier spectrum analyzer [a Fourier-transform microwave spectrometer, (FTMWS)] with no moving parts has been proposed for use in remote sensing of weak, natural microwave emissions from the surfaces and atmospheres of planets to enable remote analysis and determination of chemical composition and abundances of critical molecular constituents in space. The instrument is based on a Bessel beam (light modes with non-zero angular momenta) fiber-optic elements. It features low power consumption, low mass, and high resolution, without a need for any cryogenics, beyond what is achievable by the current state-of-the-art in space instruments. The instrument can also be used in a wide-band scatterometer mode in active radar systems.

Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry

2009-01-01

207

Very Compact Expressions for Amplitudes  

E-print Network

A number theoretic algorithm is given for writing gauge theory amplitudes in a compact manner. It is possible to write down all details of the complete $L$ loop amplitude with two integers, or a complex integer. However, a more symmetric notation requires more integers, five or seven, depending on the type of theory. It is possible that in the symmetric form (or in the non-symmetric form) that a direct (or less direct) recursive algorithm or generating function can be developed to compute these numbers at arbitrary loop order. The existence of this function is implied by the recursive structure of loop amplitudes and their analyticity, i.e. multi-particle poles; a function requiring a finite number of computations such as a polynomial with derivable coefficients is desired.

Gordon Chalmers

2005-02-10

208

Studies of accelerated compact toruses  

SciTech Connect

In an earlier publication we considered acceleration of plasma rings (Compact Torus). Several possible accelerator configurations were suggested and the possibility of focusing the accelerated rings was discussed. In this paper we consider one scheme, acceleration of a ring between coaxial electrodes by a B/sub theta/ field as in a coaxial rail-gun. If the electrodes are conical, a ring accelerated towards the apex of the cone undergoes self-similar compression (focusing) during acceleration. Because the allowable acceleration force, F/sub a/ = kappaU/sub m//R where (kappa < 1), increases as R/sup -2/, the accelerating distance for conical electrodes is considerably shortened over that required for coaxial electrodes. In either case, however, since the accelerating flux can expand as the ring moves, most of the accelerating field energy can be converted into kinetic energy of the ring leading to high efficiency.

Hartman, C.W.; Eddleman, J.; Hammer, J.H.

1983-01-04

209

Power burner for compact furnace  

SciTech Connect

A compact gas power burner is provided which includes a cylindrical mixing tube into which combustion air is discharged tangentially from a centrifugal blower located adjacent the closed end of the mixing tube, and gaseous fuel is admitted into the discharge airstream of the blower upstream from the admission location of the airstream into the mixing tube so that the swirling component of the air in the mixing tube during its passage to the open end of the tube will promote the mixing of the air and gaseous fuel, the mixing tube being provided with a honeycomb ceramic disc at its end to which it is attached to a cylindrical heat exchanger, and ignition means and flame sensors are provided on the downstream side of the ceramic disc.

Dilmore, J.A.

1980-09-23

210

General Relativity&Compact Stars  

SciTech Connect

Compact stars--broadly grouped as neutron stars and white dwarfs--are the ashes of luminous stars. One or the other is the fate that awaits the cores of most stars after a lifetime of tens to thousands of millions of years. Whichever of these objects is formed at the end of the life of a particular luminous star, the compact object will live in many respects unchanged from the state in which it was formed. Neutron stars themselves can take several forms--hyperon, hybrid, or strange quark star. Likewise white dwarfs take different forms though only in the dominant nuclear species. A black hole is probably the fate of the most massive stars, an inaccessible region of spacetime into which the entire star, ashes and all, falls at the end of the luminous phase. Neutron stars are the smallest, densest stars known. Like all stars, neutron stars rotate--some as many as a few hundred times a second. A star rotating at such a rate will experience an enormous centrifugal force that must be balanced by gravity or else it will be ripped apart. The balance of the two forces informs us of the lower limit on the stellar density. Neutron stars are 10{sup 14} times denser than Earth. Some neutron stars are in binary orbit with a companion. Application of orbital mechanics allows an assessment of masses in some cases. The mass of a neutron star is typically 1.5 solar masses. They can therefore infer their radii: about ten kilometers. Into such a small object, the entire mass of our sun and more, is compressed.

Glendenning, Norman K.

2005-08-16

211

Ductile compaction in volcanic conduits  

NASA Astrophysics Data System (ADS)

Silicic magmas typically outgas through connected pore and crack networks with a high gas permeability without the need for decoupled movement of pores in the melt. It is the efficiency with which this process can occur which governs the pressure in the pore network. However, such a connected coupled network is generally mechanically unstable and will relax until volume equilibrium when the pores become smaller and isolated. Consequently, gas permeability can be reduced during densification. Cycles of outgassing events recorded in gas monitoring data show that permeable flow of volatiles is often transient, which is interpreted to reflect magma densification and the closing of pore-networks. Understanding the timescale over which this densification process occurs is critical to refining conduit models that seek to predict the pressure evolution in a pore-network leading to eruptions. We conduct uniaxial compaction experiments to parameterize non-linear creep and relaxation processes that occur in magmas with total pore fractions 0.2-0.85. We analyze our results by applying both viscous sintering and viscoelastic deformation theory to test the applicability of currently accepted models to flow dynamics in the uppermost conduit involving highly porous magmas. We show that purely ductile compaction can occur rapidly and that pore networks can close over timescales analogous to the inter-eruptive periods observed during classic cyclic eruptions such as those at Soufriere Hills volcano, Montserrat, in 1997. At upper-conduit axial stresses (0.1-5 MPa) and magmatic temperatures (830-900 oC), we show that magmas can evolve to porosities analogous to dome lavas erupted at the same volcano. Such dramatic densification events over relatively short timescales and in the absence of brittle deformation show that permeable flow will be inhibited at upper conduit levels. We therefore propose that outgassing is a key feature at many silicic volcanoes and should be incorporated into conduit flow models.

Wadsworth, Fabian; Vasseur, Jeremie; Lavallée, Yan; Scheu, Bettina; Dingwell, Donald

2014-05-01

212

78 FR 61384 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact  

Federal Register 2010, 2011, 2012, 2013

...notify the Federal Bureau of Investigation (FBI) Compact Officer, Mr. Gary S. Barron...may be addressed to Mr. Gary S. Barron, FBI Compact Officer, Module D3, 1000 Custer...September 25, 2013. Gary S. Barron, FBI Compact Officer, Criminal Justice...

2013-10-03

213

76 FR 66326 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact  

Federal Register 2010, 2011, 2012, 2013

...the Council should notify the Federal Bureau Of Investigation (FBI) Compact Officer, Mr. Gary S. Barron at (304) 625-2803...CONTACT: Inquiries may be addressed to Mr. Gary S. Barron, FBI Compact Officer, Compact Council Office, Module D3, 1000...

2011-10-26

214

77 FR 20051 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact  

Federal Register 2010, 2011, 2012, 2013

...notify the Federal Bureau of Investigation (FBI) Compact Officer, Mr. Gary S. Barron...may be addressed to Mr. Gary S. Barron, FBI Compact Officer, Module D3, 1000 Custer...Dated: March 27, 2012. Gary S. Barron, FBI Compact Officer, Criminal Justice...

2012-04-03

215

77 FR 60475 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact  

Federal Register 2010, 2011, 2012, 2013

...notify the Federal Bureau Of Investigation (FBI) Compact Officer, Mr. Gary S. Barron...may be addressed to Mr. Gary S. Barron, FBI Compact Officer, Module D3, 1000 Custer...September 19, 2012. Gary S. Barron, FBI Compact Officer, Criminal Justice...

2012-10-03

216

75 FR 62568 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact  

Federal Register 2010, 2011, 2012, 2013

...the Council should notify the Federal Bureau of Investigation (FBI) Compact Officer, Mr. Gary S. Barron at (304) 625-2803...CONTACT: Inquiries may be addressed to Mr. Gary S. Barron, FBI Compact Officer, Compact Council Office, Module D3, 1000...

2010-10-12

217

78 FR 20355 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact  

Federal Register 2010, 2011, 2012, 2013

...notify the Federal Bureau of Investigation (FBI) Compact Officer, Mr. Gary S. Barron...may be addressed to Mr. Gary S. Barron, FBI Compact Officer, Module D3, 1000 Custer...Dated: March 26, 2013. Gary S. Barron, FBI Compact Officer, Criminal Justice...

2013-04-04

218

The Effect of Laboratory Compaction on the Compressibility of a Compacted Highly Plastic Clay.  

National Technical Information Service (NTIS)

The compressibility of the plastic St. Croix clay is to be studied for both laboratory and field compaction. This interim report deals with the laboratory-compacted phase. The clay was compacted to three levels of kneading type effort and at water content...

A. DiBernardo, C. W. Lovell

1979-01-01

219

Crop responses to applied soil compaction and to compaction repair treatments  

Microsoft Academic Search

Crop responses to annual compaction treatments (applied to whole plots) and management treatments to ameliorate compacted soil were determined in a field experiment on a Vertisol. Initially, all treatments except a control were compacted with a 10Mg axle load on wet soil (26% gravimetric water content compared with a plastic limit of 22%). Annually applied axle loads of 10 and

B. J Radford; D. F Yule; D McGarry; C Playford

2001-01-01

220

Atomic compactness and reflexive graphs. Christian DELHOMM '  

E-print Network

Atomic compactness and reflexive graphs. Christian DELHOMM ' E Universit¨at Bielefeld Abstract A first order structure M with universe M is atomic compact if every system of atomic formulas with parameters in M is satisfiable in M provided each of its finite subsystems is. The definition of atomic

Bielefeld, University of

221

Hydraulic conductivity tests on compacted clay  

Microsoft Academic Search

Permeability tests were performed in the laboratory on compacted clay to study the effects of type of permeameter, hydraulic anisotropy, diameter of test specimens, storage time, and desiccation cracking. Essentially identical hydraulic conductivities were measured with compaction-mold, consolidationcell, and flexible-wall permeameters. With good bonding between lifts, hydraulic conductivity was isotropic. Test specimens having a diameter of 15 cm were twice

Stephen S. Boynton; David E. Daniel

1985-01-01

222

Exploration of Compact Stellarators as Power Plants  

E-print Network

Exploration of Compact Stellarators as Power Plants: Initial Results from ARIES-CS Study Farrokh, see: http://aries.ucsd.edu/ #12;Exploration and Optimization of Compact Stellarators as Power Plants in the context of power plant studies, e.g., particle loss Divertor (location, particle and energy distribution

California at San Diego, University of

223

Evaluation of compaction rates for decompaction processes  

Microsoft Academic Search

Burial of sediment leads to mechanical compaction with diminution of both porosity and initial thickness. The compaction rate, tau = hâ\\/h, may be either directly measured in the sediment or estimated from variation of porosity. Examples of direct measures are given for different facies on the basis of: textural variations (density of grains, fossil debris, burrows, etc); deformation of fossils

B. Beaudoin; I. Cojan; G. Fries; B. Pinoteau

1987-01-01

224

Compacted Soil Liner Interface Strength Importance  

E-print Network

Case Study Compacted Soil Liner Interface Strength Importance Timothy D. Stark, F.ASCE1 ; Hangseok interface is not the geomembrane (GM)/compacted low-permeability soil liner (LPSL) but a soil�soil interface moisture content should be controlled so it does not exceed the specified value, for example 3�4% wet

225

Global Compact for Higher Education Institutions  

E-print Network

,000 students - Over 4,500 foreign students from 113 countries - A total of 248,690 graduates sinceGlobal Compact for Higher Education Institutions Communicating on Progress for Université Laval Guide to the United Nations Global Compact for Higher Education Institutions: Implementing the Global

226

Tropical residual soil as compacted soil liners  

Microsoft Academic Search

A series of laboratory tests was conducted on a tropical residual soil, which is widespread and readily available over a considerable part of Peninsular Malaysia, to assess whether it could be compacted as hydraulic barriers in waste disposal landfills. Index properties, swelling potential, cation exchange capacity (CEC), compaction characteristics, and hydraulic conductivity of the soil indicate that it is inorganic,

M. R. Taha; M. H. Kabir

2005-01-01

227

Cooling of Color Superconducting Compact Stars  

E-print Network

We review the status of research on the cooling of compact stars, with emphasis on the influence of color superconducting quark matter phases. Although a consistent microscopic approach is not yet available, severe constraints on the phase structure of matter at high densities come from recent mass and cooling observations of compact stars.

David Blaschke

2006-03-26

228

Intelligent Compaction: A Minnesota Case History  

Microsoft Academic Search

Intelligent Compaction (IC) uses an instrumented roller to provide continuous, real time verification of in situ soil properties over the entire compaction area. Ammann, Bomag and Caterpillar compactors were used on three trunk highway projects in Minnesota during 2005. The objective of this study was to compare quality control data from an IC roller with quality assurance data collected from

F. Camargo; B. Larsen; B. Chadbourn; R. Roberson; J. Siekmeier

229

Shock compaction of molybdenum nitride powder  

NASA Astrophysics Data System (ADS)

Molybdenum nitride has a potential application in multi layer capacitors. Since this material is not readily available in bulk form, molybdenum nitride powder, consisting of a mixture of the nitrides Mo2N and MoN has been compacted to 12 mm circular, 1-2 mm thick discs utilizing shock-compression technique. Powders were packed to 55-67 percent of the crystal density and shock compacted using a plate impact shock recovery system at 1.35 to 1.81 km/s impact velocity. The recovered compacts were characterized by scanning electron microscope, x-ray diffraction and cyclic voltammetry to evaluate its electrochemical stability in sulphuric acid. This paper presents the optimization technique used for compaction and the characteristics of the recovered compacts.

Roberson, S.; Davis, R. F.; Joshi, V. S.; Fienello, D.

1998-07-01

230

Charge regulation circuit  

DOEpatents

A charge regulation circuit provides regulation of an unregulated voltage supply in the range of 0.01%. The charge regulation circuit is utilized in a preferred embodiment in providing regulated voltage for controlling the operation of a laser.

Ball, Don G. (Livermore, CA)

1992-01-01

231

Some new Wyman-Adler type static relativistic charged anisotropic fluid spheres compatible to \\emph{self-bound} stellar modeling  

E-print Network

In this work some families of relativistic anisotropic charged fluid spheres have been obtained by solving Einstein-Maxwell field equations with preferred form of one of the metric potentials, a suitable forms of electric charge distribution and pressure anisotropy functions. The resulting equation of state (EOS) of the matter distribution has been obtained. Physical analysis shows that the relativistic stellar structure for matter distribution obtained in this work may reasonably model an electrically charged compact star whose energy density associated with the electric fields is on the same order of magnitude as the energy density of fluid matter itself (e.g. electrically charged bare strange stars). These models permit a simple method of systematically fixing bounds on the maximum possible mass of cold compact electrically charged self-bound stars. It has been demonstrated numerically that the maximum compactness and mass increase in the presence of electric field and anisotropic pressures. Based on the a...

Murad, Mohammad Hassan

2014-01-01

232

Storage Battery Charging  

Microsoft Academic Search

The fundamental reactions in accordance with the generally accepted ``double-sulphate'' theory of storage battery charging are comparatively simple. Additional reactions and phenomena, such as gas evolution, acid concentration, heating, and local action are factors which affect charging conditions. Data showing the effects of these factors are given in this paper. The ampere-hour law regarding charging rates is illustrated. Results of

J. Lester Woodbridge

1935-01-01

233

More about Charging Things  

NSDL National Science Digital Library

In the first chapter, you charged things up with excess electrons and saw what could happen as a result. Now we're going to get an idea of how to measure how much charge something has, figure out whether an object is positively or negatively charged, and make up a new concept called the electric field.

Robertson, William C.

2005-01-01

234

Spacecraft Charging Technology, 1980  

NASA Technical Reports Server (NTRS)

The third Spacecraft Charging Technology Conference proceedings contain 66 papers on the geosynchronous plasma environment, spacecraft modeling, charged particle environment interactions with spacecraft, spacecraft materials characterization, and satellite design and testing. The proceedings is a compilation of the state of the art of spacecraft charging and environmental interaction phenomena.

1981-01-01

235

National Compact Stellarator Experiment Project Closeout Report PROJECT CLOSEOUT REPORT  

E-print Network

National Compact Stellarator Experiment Project Closeout Report i PROJECT CLOSEOUT REPORT NATIONAL of Science Princeton Plasma Physics Laboratory Oak Ridge National Laboratory #12;National Compact Stellarator Experiment Project Closeout Report PROJECT CLOSEOUT REPORT NATIONAL COMPACT STELLARATOR EXPERIMENT (NCSX

Princeton Plasma Physics Laboratory

236

A compact high power pulsed modulator based on spiral Blumlein line.  

PubMed

A compact high power pulsed modulator based on spiral water Blumlein line, which consists of primary storage capacitors, a Tesla transformer, a spiral Blumlein line of water dielectric, and a field-emission diode, is described. The experimental results showed that the diode voltage is more than 500 kV, the electron beam current of diode is about 32 kA, and the pulse duration is about 180 ns. The distributions for electrical field in the spiral water Blumlein line were obtained by the simulations. In addition, the process of the charging a spiral Blumlein line was simulated through the PSPICE software to get the wave form of charging voltage of pulse forming line, the diode voltage, and diode current of modulator. The theoretical and simulated results are in agreement. This accelerator is very compact and works stably and reliably. PMID:17979411

Liu, Jinliang; Yin, Yi; Ge, Bin; Cheng, Xinbing; Feng, Jiahuai; Zhang, Jiande; Wang, Xinxin

2007-10-01

237

Compact drilling and sample system  

NASA Technical Reports Server (NTRS)

The Compact Drilling and Sample System (CDSS) was developed to drill into terrestrial, cometary, and asteroid material in a cryogenic, vacuum environment in order to acquire subsurface samples. Although drills were used by the Apollo astronauts some 20 years ago, this drill is a fraction of the mass and power and operates completely autonomously, able to drill, acquire, transport, dock, and release sample containers in science instruments. The CDSS has incorporated into its control system the ability to gather science data about the material being drilled by measuring drilling rate per force applied and torque. This drill will be able to optimize rotation and thrust in order to achieve the highest drilling rate possible in any given sample. The drill can be commanded to drill at a specified force, so that force imparted on the rover or lander is limited. This paper will discuss the cryo dc brush motors, carbide gears, cryogenic lubrication, quick-release interchangeable sampling drill bits, percussion drilling and the control system developed to achieve autonomous, cryogenic, vacuum, lightweight drilling.

Gillis-Smith, Greg R.; Petercsak, Doug

1998-01-01

238

Spectral responses in granular compaction  

NASA Astrophysics Data System (ADS)

I study the compaction of a granular pack under periodic tapping. The magnitude of acceleration ? at each tap is modulated with frequency ? and amplitude ??: ?(t) = ?DC + ??(?t), where t is time measured by the number of taps. From the temporal modulation ?v in packing volume v, frequency- locked to the modulated tapping input, we can define the real and imaginary volume susceptibilities ?v' = (?v/??) ? and ?v'' = (?v/??) ?; here ? is the phase lag between ?(t) and v(t). As a function of ?DC, ?v', ?v'' are peaked at low ?DC, a behavior reminiscent of the temperature-dependent susceptibilities in dielectric and spin glasses. For the packing of small particles (d = 0.5 mm) in ambient pressure, ?v' exhibits memory and rejuvenation effects under ?DC cycling, similar to that seen in the magnetic susceptibility of spin glasses when subjected to thermal cycling [1]. However this memory effect is suppressed for the packing of larger particles and in vacuum. The measurement of volume susceptibilities shows promise as a new way to study the packing of granular materials, and as an avenue to explore analogies between jammed grains and molecular and spin glasses. [3pt] [1] K. Jonason et al., Phys. Rev. Lett. 81, 3243 (1998).

Zou, Ling-Nan

2009-03-01

239

Thermodynamic analysis of compact formation; compaction, unloading, and ejection. I. Design and development of a compaction calorimeter and mechanical and thermal energy determinations of powder compaction.  

PubMed

The aim of this investigation was to determine and evaluate the thermodynamic properties, i.e. heat, work, and internal energy change, of the compaction process by developing a 'Compaction Calorimeter'. Compaction of common excipients and acetaminophen was performed by a double-ended, constant-strain tableting waveform utilizing an instrumented 'Compaction Simulator.' A constant-strain waveform provides a specific quantity of applied compaction work. A calorimeter, built around the dies, used a metal oxide thermistor to measure the temperature of the system. A resolution of 0.0001 degrees C with a sampling time of 5 s was used to monitor the temperature. An aluminum die within a plastic insulating die, in conjunction with fiberglass punches, comprised the calorimeter. Mechanical (work) and thermal (heat) calibrations of the elastic punch deformation were performed. An energy correction method was outlined to account for system heat effects and mechanical work of the punches. Compaction simulator transducers measured upper and lower punch forces and displacements. Measurements of the effective heat capacity of the samples were performed utilizing an electrical resistance heater. Specific heat capacities of the samples were determined by differential scanning calorimetry. The calibration techniques were utilized to determine heat, work, and the change in internal energies of powder compaction. Future publications will address the thermodynamic evaluation of the tablet sub-processes of unloading and ejection. PMID:10722955

DeCrosta, M T; Schwartz, J B; Wigent, R J; Marshall, K

2000-03-30

240

Compact Dielectric Wall Accelerator Development For Intensity Modulated Proton Therapy And Homeland Security Applications  

SciTech Connect

Compact dielectric wall (DWA) accelerator technology is being developed at the Lawrence Livermore National Laboratory. The DWA accelerator uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradient insulating (HGI) acceleration tube. Its high electric field gradients are achieved by the use of alternating insulators and conductors and short pulse times. The DWA concept can be applied to accelerate charge particle beams with any charge to mass ratio and energy. Based on the DWA system, a novel compact proton therapy accelerator is being developed. This proton therapy system will produce individual pulses that can be varied in intensity, energy and spot width. The system will be capable of being sited in a conventional linac vault and provide intensity modulated rotational therapy. The status of the developmental new technologies that make the compact system possible will be reviewed. These include, high gradient vacuum insulators, solid dielectric materials, SiC photoconductive switches and compact proton sources. Applications of the DWA accelerator to problems in homeland security will also be discussed.

Chen, Y -; Caporaso, G J; Guethlein, G; Sampayan, S; Akana, G; Anaya, R; Blackfield, D; Cook, E; Falabella, S; Gower, E; Harris, J; Hawkins, S; Hickman, B; Holmes, C; Horner, A; Nelson, S; Paul, A; Pearson, D; Poole, B; Richardson, R; Sanders, D; Stanley, J; Sullivan, J; Wang, L; Watson, J; Weir, J

2009-06-17

241

Effect of H-NS on the elongation and compaction of single DNA molecules in a nanospace  

E-print Network

multivalent cationic ligand, because it does not compact DNA into a structure with an ordered morphology.1 H-NS binds and oligomerizes along double stranded DNA to form a semi- rigid nucleoprotein lament-charge attraction between distal DNA segments by the binding protein (bridging) is also thought to be important.4

Doyle, Patrick S.

242

The RADAN series of compact pulsed power Generators and their applications  

Microsoft Academic Search

This paper presents results of development of a compact pulsed power high-voltage generators and high-current electron accelerators of the RADAN series. The basic high-voltage units of RADAN instruments are built around coaxial pulsed forming lines and efficient charging device represented by a Tesla transformer. The fields of applications in science and in practice are rather wide and include formation of

GENNADY A. MESYATS; SERGEI D. KOROVIN; VLADISLAV V. ROSTOV; VALERY G. SHPAK; MICHAEL I. YALANDIN

2004-01-01

243

Pentagon Equation and Compact Quantum Semigroups  

E-print Network

The generalization of multiplicative unitary notion from compact quantum groups to compact quantum semigroups is considered. We show why the same construction doesn't work in this case by giving examples of C*-algebras with non-trivial comultiplication which do not admit multiplicative unitaries. By the use of the pentagon equation we suggest a notion of an operator which gives comultiplication on any C*-algebra. The multiplicative unitary turns out to be its special case. We prove for some compact quantum semigroups that the comultiplication is given by such operator.

Aukhadiev, Marat Alfredovich

2011-01-01

244

Compaction dynamics in ductile granular media  

E-print Network

Ductile compaction is common in many natural systems, but the temporal evolution of such systems is rarely studied. We observe surprising oscillations in the weight measured at the bottom of a self-compacting ensemble of ductile grains. The oscillations develop during the first ten hours of the experiment, and usually persist through the length of an experiment (one week). The weight oscillations are connected to the grain--wall contacts, and are directly correlated with the observed strain evolution and the dynamics of grain--wall contacts during the compaction. Here, we present the experimental results and characteristic time constants of the system, and discuss possible reasons for the measured weight oscillations.

Lina Uri; Dag Kristian Dysthe; Jens Feder

2005-10-19

245

Compact Zwitterion-Coated Iron Oxide Nanoparticles for Biological Applications  

PubMed Central

The potential of superparamagnetic iron oxide nanoparticles (SPIONs) in various biomedical applications, including magnetic resonance imaging (MRI), sensing, and drug delivery, requires that their surface be derivatized to be hydrophilic and biocompatible. We report here the design and synthesis of a compact and water-soluble zwitterionic dopamine sulfonate (ZDS) ligand with strong binding affinity to SPIONs. After ligand exchange, the ZDS coated SPIONs exhibit small hydrodynamic diameters (HD), and stability with respect to time, pH, and salinity. Furthermore, small ZDS coated SPIONs were found to have a reduced non-specific affinity (compared to negatively charged SPIONs) towards serum proteins; streptavidin/dye functionalized SPIONs were bioactive and thus specifically targeted biotin receptors. PMID:22185195

Wei, He; Insin, Numpon; Lee, Jungmin; Han, Hee-Sun; Cordero, Jose M.; Liu, Wenhao; Bawendi, Moungi G.

2012-01-01

246

A compact bipolar pulse-forming network-Marx generator based on pulse transformers.  

PubMed

A compact bipolar pulse-forming network (PFN)-Marx generator based on pulse transformers is presented in this paper. The high-voltage generator consisted of two sets of pulse transformers, 6 stages of PFNs with ceramic capacitors, a switch unit, and a matched load. The design is characterized by the bipolar pulse charging scheme and the compact structure of the PFN-Marx. The scheme of bipolar charging by pulse transformers increased the withstand voltage of the ceramic capacitors in the PFNs and decreased the number of the gas gap switches. The compact structure of the PFN-Marx was aimed at reducing the parasitic inductance in the generator. When the charging voltage on the PFNs was 35 kV, the matched resistive load of 48 ? could deliver a high-voltage pulse with an amplitude of 100 kV. The full width at half maximum of the load pulse was 173 ns, and its rise time was less than 15 ns. PMID:24289423

Zhang, Huibo; Yang, Jianhua; Lin, Jiajin; Yang, Xiao

2013-11-01

247

Pharmaceutical tablet compaction : product and process design  

E-print Network

This thesis explores how tablet performance is affected by microstructure, and how microstructure can be controlled by selection of excipients and compaction parameters. A systematic strategy for formulation and process ...

Pore, Mridula

2009-01-01

248

A CMOS-compatible compact display  

E-print Network

Portable information devices demand displays with high resolution and high image quality that are increasingly compact and energy-efficient. Microdisplays consisting of a silicon CMOS backplane integrated with light ...

Chen, Andrew R. (Andrew Raymond)

2005-01-01

249

ACTIVELY CONTROLLED AFTERBURNER FOR COMPACT WASTE INCINERATION  

EPA Science Inventory

In a continuing research program directed at developing technology for compact shipboard incinerators, active control of fluid dynamics has been used to enhance mixing in incinerator afterburner (AB) experiments and increase the DRE for a waste surrogate. Experiments were conduc...

250

The EBIT charge breeder at NSCL  

NASA Astrophysics Data System (ADS)

The National Superconducting Cyclotron Laboratory (NSCL) is finalizing ReA to reaccelerate rare-isotope beams to energies of ˜0.3-20 MeV/u. ReA consists of an electron-beam ion source / trap (EBIS/T), a mass separator, a radio-frequency quadrupole (RFQ) pre-accelerator, and a superconducting radio-frequency linear accelerator (SRF-LINAC). By increasing the charge of ions injected into the RFQ and SRF-LINAC, this charge breeder is a key component to provide a compact and cost-efficient reaccelerator. The ReA EBIT has started producing highly charged ion beams. It is equipped with an electron gun yielding a few amperes and a magnet configuration made of Helmholtz coils and a solenoid, providing a maximum magnetic field strength of 6 T. The solenoid magnet configuration will guarantee high beam acceptance. The combination of a high-current gun and strong magnetic field will allow this EBIS/T to reach high electron current densities suitable to rapidly increase the charge of short-lived isotopes within tens of milliseconds. The status of the EBIT will be presented.

Lapierre, Alain; Schwarz, Stefan; Kittimanapun, Kritsada; Bollen, Georg; Kester, Oliver

2011-10-01

251

Electric Charge and Electric Field Electrostatics: Charge at rest  

E-print Network

Chapter 16 Electric Charge and Electric Field #12;Electrostatics: Charge at rest Electric Charges of conservation of Electric Charge: The net amount of electric charge produced in any process is zero. Model, neutral). #12;� All protons and electrons have same magnitude of electric charge but their masses

Yu, Jaehoon

252

Ceramic granule strength variability and compaction behavior  

Microsoft Academic Search

Diametral compression strength distributions and the compaction behavior and of irregular shape 150--200 μm ceramic granules and uniform-size 210 μm glass spheres were measured to determine how granule strength variability relates to compaction behavior of granular assemblies. High variability in strength, represented by low Weibull modulus values (m<3) was observed for ceramic granules having a distribution of sizes and shapes,

S. J. Glass; K. G. Ewsuk; M. J. Readey

1995-01-01

253

Compactness of Hardy–Steklov operator  

Microsoft Academic Search

Pair of weights u, v is characterized so that the Hardy–Steklov operator (Tf)(x)=?a(x)b(x)f(t)dt is compact between weighted Lebesgue spaces Lp(u) and Lq(v), where 1compactness of the conjugate operator (T?f)(x)=?b?1(x)a?1(x)f(t)dt is also studied.

Pankaj Jain; Babita Gupta

2003-01-01

254

Stuck-at-fault test set compaction  

E-print Network

. Redundancy Elimination. Redundancy Creation, Dynamic compaction technique. Asslgnlllent Iustifllcatlon. Pattern Metric RESULTS AND ANALYSIS. , g . 9 . 9 10 ll II 12 14 Dynamic Compaction Techniques. Fault Target Selection. Pattern Metric... little value and can be expected to have less of an impact upon the defective part level than truly unique detecting patterns. In order to simplify the analysis, only the median of the excitation balance values for all faults is considered. The formula...

Vanfickell, Jason Michael

2013-02-22

255

Coulombic charge ice  

NASA Astrophysics Data System (ADS)

We consider a classical model of charges ±q on a pyrochlore lattice in the presence of long-range Coulomb interactions. This model first appeared in the early literature on charge order in magnetite [P. W. Anderson, Phys. Rev. 102, 1008 (1956), 10.1103/PhysRev.102.1008]. In the limit where the interactions become short ranged, the model has a ground state with an extensive entropy and dipolar charge-charge correlations. When long-range interactions are introduced, the exact degeneracy is broken. We study the thermodynamics of the model and show the presence of a correlated charge liquid within a temperature window in which the physics is well described as a liquid of screened charged defects. The structure factor in this phase, which has smeared pinch points at the reciprocal lattice points, may be used to detect charge ice experimentally. In addition, the model exhibits fractionally charged excitations ±q/2 which are shown to interact via a 1/r potential. At lower temperatures, the model exhibits a transition to a long-range ordered phase. We are able to treat the Coulombic charge ice model and the dipolar spin ice model on an equal footing by mapping both to a constrained charge model on the diamond lattice. We find that states of the two ice models are related by a staggering field which is reflected in the energetics of these two models. From this perspective, we can understand the origin of the spin ice and charge ice ground states as coming from a dipolar model on a diamond lattice. We study the properties of charge ice in an external electric field, finding that the correlated liquid is robust to the presence of a field in contrast to the case of spin ice in a magnetic field. Finally, we comment on the transport properties of Coulombic charge ice in the correlated liquid phase.

McClarty, P. A.; O'Brien, A.; Pollmann, F.

2014-05-01

256

Compaction of Ductile and Fragile Grains  

NASA Astrophysics Data System (ADS)

The compaction of powders into tablets is widely used in several industries (cosmetics, food, pharmaceutics…). In all these industries, the composition of the initial powder is complex, and the behaviour under compaction is not well known, also the mechanical behaviour of the tablets. The aim of this paper is to understand the behaviour (pressure vs density) of a simplified media made of fragile and ductile powders, varying the relative ratio of each powder. Some compaction experiments were carried out with glass beads (fragile) and Polyethylen Glycol powder (ductile). We observe two typical behaviours, depending on the relative volumic fraction of each component. A transition is pointed out, observing the evolution of the slope of the curve pressure/density. This transition is explained by geometrical considerations during compaction. A model is proposed, based on the assumption that the studied media can be compare to a diphasic material with a continuous phase (the ductile powder) and a discrete phase (the fragile powder). The result of this model is compare to the experimental results of compaction, and give a good prediction of the behaviour of the different mixing, knowing the behaviour of the ductile and the fragile phase separately. These results were also interpreted in terms of Heckel parameter which characterizes the ability of the powder to deform plastically under compaction. Some mechanical tests were also performed to compare the mechanical resitance of the obtained tablets.

Creissac, S.; Pouliquen, O.; Dalloz-Dubrujeaud, B.

2009-06-01

257

Charge Islands Through Tunneling  

NASA Technical Reports Server (NTRS)

It has been recently reported that the electrical charge in a semiconductive carbon nanotube is not evenly distributed, but rather it is divided into charge "islands." This paper links the aforementioned phenomenon to tunneling and provides further insight into the higher rate of tunneling processes, which makes tunneling devices attractive. This paper also provides a basis for calculating the charge profile over the length of the tube so that nanoscale devices' conductive properties may be fully exploited.

Robinson, Daryl C.

2002-01-01

258

Phase transformations in shock compacted magnetic materials  

NASA Astrophysics Data System (ADS)

Shock compaction experiments were performed on soft magnetic phases Fe 4N and Fe16N2, and hard magnetic phases Nd 2Fe14B and Sm2Fe17N3 in order to determine their thermo-mechanical stability during shock loading and explore the possibility of fabricating a textured nanocomposite magnet. Gas gun experiments performed on powders pressed in a three capsule fixture showed phase transformations occurring in Fe4N, Fe16N 2, and Nd2Fe14B, while Sm2Fe17 N3 was observed to be relatively stable. Shock compaction of FCC Fe4N resulted in a partial transformation to HCP Fe3N, consistent with previous reports of the transition occurring at a static pressure of ~3 GPa. Shock compaction of Fe16N 2 produced decomposition products ?-Fe, Fe4N, and FeN due to a combination of thermal effects associated with dynamic void collapse and plastic deformation. Decomposition of Nd-Fe-B, producing ?-Fe and amorphous Nd-Fe-B, was observed in several shock consolidated samples and is attributed to deformation associated with shock compaction, similar to decomposition reported in ball milled Nd-Fe-B. No decomposition was observed in shock compacted samples of Sm-Fe-N, which is consistent with literature reports showing decomposition occurring only in samples compacted at a pressure above ~15 GPa. Nd-Fe-B and Sm-Fe-N were shown to accommodate deformation primarily by grain size reduction, especially in large grained materials. Hard/Soft composite magnetic materials were formed by mixing single crystal particles of Nd-Fe-B with iron nanoparticles, and the alignment-by-magnetic-field technique was able to introduce significant texture into green compacts of this mixture. While problems with decomposition of the Nd2Fe14B phase prevented fabricating bulk magnets from the aligned green compacts, retention of the nanoscale morphology of the ?-Fe particles and the high alignment of the green compacts shows promise for future development of textured nanocomposite magnets through shock compaction.

Wehrenberg, Christopher

259

Convex-compact sets and Banach discs I. Monterde  

E-print Network

Convex-compact sets and Banach discs I. Monterde and V. Montesinos Abstract Every relatively convex-compact) and the Universidad Polit´ecnica de Valencia. Keywords: weakly compact sets, convex-compact sets, Banach discs. 1 #12 convex subset of a locally convex space is contained in a Banach disc. Moreover, an upper bound

Montesinos Santalucía, Vicente

260

Compaction enhancement of pharmaceutical solids by engineered plasticization  

Microsoft Academic Search

The objective of this research was two fold: to use near infrared (NIR) spectroscopy for real-time monitoring and control of key compact attributes: content uniformity, moisture content, relative density, tensile strength and Young's modulus, during roller compaction; and, to develop a model for predicting the improvement in compaction behavior, during roller compaction, due to the plasticization effect of ambient moisture.

Abhay Gupta

2004-01-01

261

A compact, all solid-state LC high voltage generator  

NASA Astrophysics Data System (ADS)

LC generator is widely applied in the field of high voltage generation technology. A compact and all solid-state LC high voltage generator based on saturable pulse transformer is proposed in this paper. First, working principle of the generator is presented. Theoretical analysis and circuit simulation are used to verify the design of the generator. Experimental studies of the proposed LC generator with two-stage main energy storage capacitors are carried out. And the results show that the proposed LC generator operates as expected. When the isolation inductance is 27 ?H, the output voltage is 1.9 times larger than the charging voltage on single capacitor. The multiplication of voltages is achieved. On the condition that the primary energy storage capacitor is charged to 857 V, the output voltage of the generator can reach to 59.5 kV. The step-up ratio is nearly 69. When self breakdown gas gap switch is used as main switch, the rise time of the voltage pulse on load resistor is 8.7 ns. It means that the series-wound inductance in the discharging circuit is very small in this system. This generator can be employed in two different applications.

Fan, Xuliang; Liu, Jinliang

2013-06-01

262

A compact, all solid-state LC high voltage generator.  

PubMed

LC generator is widely applied in the field of high voltage generation technology. A compact and all solid-state LC high voltage generator based on saturable pulse transformer is proposed in this paper. First, working principle of the generator is presented. Theoretical analysis and circuit simulation are used to verify the design of the generator. Experimental studies of the proposed LC generator with two-stage main energy storage capacitors are carried out. And the results show that the proposed LC generator operates as expected. When the isolation inductance is 27 ?H, the output voltage is 1.9 times larger than the charging voltage on single capacitor. The multiplication of voltages is achieved. On the condition that the primary energy storage capacitor is charged to 857 V, the output voltage of the generator can reach to 59.5 kV. The step-up ratio is nearly 69. When self breakdown gas gap switch is used as main switch, the rise time of the voltage pulse on load resistor is 8.7 ns. It means that the series-wound inductance in the discharging circuit is very small in this system. This generator can be employed in two different applications. PMID:23822362

Fan, Xuliang; Liu, Jinliang

2013-06-01

263

A study of compaction bands originating from cracks, notches, and compacted defects  

E-print Network

A study of compaction bands originating from cracks, notches, and compacted defects R. Katsman *, E at the macroscopic void's tips, and propagated in a step-wise manner, in agreement with experimental results, occurring in initially high porosity rocks subjected to high mean and low differential compressive stress

Einat, Aharonov

264

Entomology and Nematology Academic Learning Compact 1. Academic Learning Compact for a major in Entomology & Nematology B.S.  

E-print Network

1 Entomology and Nematology Academic Learning Compact 1. Academic Learning Compact for a major in Entomology & Nematology B.S. 2. What are Academic Learning Compacts? Academic Learning Compacts. 3. Students pursuing a degree in Entomology & Nematology are offered flexibility in a curriculum

Jawitz, James W.

265

Three Charged Particles Model  

NSDL National Science Digital Library

The Ejs Three Charged Particles model displays up three charged objects, one at each corner of an equilateral triangle. The charges have different magnitudes - your job is to rank the charges based on their magnitudes, from largest to smallest. You can drag the charges around to see the effect on the net force on each charge. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. Ejs Three Charged Particles model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_three_charges.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for Newtonian mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Duffy, Andrew

2008-07-14

266

Do charged leptons oscillate?  

NASA Astrophysics Data System (ADS)

The question of whether charged leptons oscillate is discussed in detail, with a special emphasis on the coherence properties of the charged lepton states created via weak interactions. This analysis allows one to clarify also an important issue of the theory of neutrino oscillations.

Akhmedov, Evgeny Kh.

2007-09-01

267

Strategy Guideline: Compact Air Distribution Systems  

SciTech Connect

This Strategy Guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. Traditional systems sized by 'rule of thumb' (i.e., 1 ton of cooling per 400 ft2 of floor space) that 'wash' the exterior walls with conditioned air from floor registers cannot provide appropriate air mixing and moisture removal in low-load homes. A compact air distribution system locates the HVAC equipment centrally with shorter ducts run to interior walls, and ceiling supply outlets throw the air toward the exterior walls along the ceiling plane; alternatively, high sidewall supply outlets throw the air toward the exterior walls. Potential drawbacks include resistance from installing contractors or code officials who are unfamiliar with compact air distribution systems, as well as a lack of availability of low-cost high sidewall or ceiling supply outlets to meet the low air volumes with good throw characteristics. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balanced HVAC system, and overall improved energy efficiency of the home.

Burdick, A.

2013-06-01

268

Rain Drop Charge Sensor  

NASA Astrophysics Data System (ADS)

begin{center} Large Large Rain Drop Charge Sensor Sreekanth T S*, Suby Symon*, G. Mohan Kumar (1) , S. Murali Das (2) *Atmospheric Sciences Division, Centre for Earth Science Studies, Thiruvananthapuram 695011 (1) D-330, Swathi Nagar, West Fort, Thiruvananthapuram 695023 (2) Kavyam, Manacaud, Thiruvananthapuram 695009 begin{center} ABSTRACT To study the inter-relations with precipitation electricity and precipitation microphysical parameters a rain drop charge sensor was designed and developed at CESS Electronics & Instrumentation Laboratory. Simultaneous measurement of electric charge and fall speed of rain drops could be done using this charge sensor. A cylindrical metal tube (sensor tube) of 30 cm length is placed inside another thick metal cover opened at top and bottom for electromagnetic shielding. Mouth of the sensor tube is exposed and bottom part is covered with metal net in the shielding cover. The instrument is designed in such a way that rain drops can pass only through unhindered inside the sensor tube. When electrically charged rain drops pass through the sensor tube, it is charged to the same magnitude of drop charge but with opposite polarity. The sensor tube is electrically connected the inverted input of a current to voltage converter operational amplifier using op-amp AD549. Since the sensor is electrically connected to the virtual ground of the op-amp, the charge flows to the ground and the generated current is converted to amplified voltage. This output voltage is recorded using a high frequency (1kHz) voltage recorder. From the recorded pulse, charge magnitude, polarity and fall speed of rain drop are calculated. From the fall speed drop diameter also can be calculated. The prototype is now under test running at CESS campus. As the magnitude of charge in rain drops is an indication of accumulated charge in clouds in lightning, this instrument has potential application in the field of risk and disaster management. By knowing the charge magnitude of initial drops from a precipitation event, gross cloud charge can be estimated and necessary precautions can be taken during convective cloud events. Being a site of high lightning incidence in tropics, Kerala state is affected in India and calls for much attention in lightning hazards mitigation. Installing this charge sensor and atmospheric electric field mill, an attempt to a better warning system can be attempted.

S, Sreekanth T.

269

Spacecraft Charging and Mitigation  

NASA Astrophysics Data System (ADS)

Satellites and spacecraft materials can become charged to tens or even thousands of volts when ions in the space environment collide with spacecraft. This can sometimes cause electrical discharge of differentially or internally charged spacecraft materials, which can adversely affect satellite operations. Additionally, high-energy ions can penetrate spacecraft materials and deposit their energy within sensitive electronics, causing component damage or failure. To consider various approaches for spacecraft charge mitigation, 150 technologists from around the world representing government, academia, and industry met at the 11th Spacecraft Charging Technology Conference (SCTC) in Albuquerque, N. M., on 20-24 September 2010. The conference was held against the backdrop of the apparent charging event of the Galaxy 15 satellite, which some speculate triggered this geosynchronous communications satellite to cease operations, thereby adversely affecting related satellite-reliant communities (see J. Allen, Space Weather, 8, S06008, doi:10.1029/2010SW000588, 2010)

Denig, William; Cooke, David; Ferguson, Dale

2010-10-01

270

Spacecraft surface charging handbook  

NASA Astrophysics Data System (ADS)

Spacecraft surface charging is the buildup of net electric charge - and therefore electrostatic potential - on the external surfaces of a spacecraft due to incident particles with energies in the kilo-electron volt to tens of kilo-electron volts range. Geosynchronous and low-altitude, polar-orbiting spacecraft encounter charging environments. Surface charging causes problems for operational spacecraft. A primary effect is the occurrence of electronic switching anomalies which can be triggered by differential charging related discharges. The discharge induced transients can cause system failures and potentially, material damage. A more common anomaly is a phantom command, requiring intervention from the ground, and possibly resulting in loss of data and/or expendables, thus shortening the operational lifetime of the spacecraft. The work of the early 1980's provided designers with tools to reduce the number and severity of anomalies. Over the past 10 years, concern has arisen regarding charging on low-altitude, polar orbiting spacecraft due to auroral precipitation. Additionally, with the miniaturization of components, modern spacecraft are more vulnerable to EMI. This handbook was developed to address some of these concerns. The scientific issues of concern in spacecraft surface charging are reviewed, the components of a spacecraft surface charging control plan are described, and the techniques used to avoid spacecraft surface charging problems are summarized. Examples are provided of (1) calculational techniques to evaluate the expected effects of a spacecraft design, and (2) experimental techniques to test immunity to spacecraft surface charging effects. Information on the environments found in the geosynchronous and auroral region and the surface material properties that can affect surfaces are also given.

Davis, V. A.; Gordon, L. W.

1992-11-01

271

Ch 16 Electric Charge &Ch 16. Electric Charge & Electric Field  

E-print Network

move aroundSemiconductors: some Metals Insulators: almost none free electrons that can move around charges attract Liu UCD Phy1B 2012 #12;Electric ChargeElectric Charge Electron charge: -eElectron charge;Insulators & ConductorsInsulators & Conductors Conductors: lots ofConductors: lots of free electrons that can

Yoo, S. J. Ben

272

DNA compaction induced by a cationic polymer or surfactant impact gene expression and DNA degradation.  

PubMed

There is an increasing interest in achieving gene regulation in biotechnological and biomedical applications by using synthetic DNA-binding agents. Most studies have so far focused on synthetic sequence-specific DNA-binding agents. Such approaches are relatively complicated and cost intensive and their level of sophistication is not always required, in particular for biotechnological application. Our study is inspired by in vivo data that suggest that DNA compaction might contribute to gene regulation. This study exploits the potential of using synthetic DNA compacting agents that are not sequence-specific to achieve gene regulation for in vitro systems. The semi-synthetic in vitro system we use include common cationic DNA-compacting agents, poly(amido amine) (PAMAM) dendrimers and the surfactant hexadecyltrimethylammonium bromide (CTAB), which we apply to linearized plasmid DNA encoding for the luciferase reporter gene. We show that complexing the DNA with either of the cationic agents leads to gene expression inhibition in a manner that depends on the extent of compaction. This is demonstrated by using a coupled in vitro transcription-translation system. We show that compaction can also protect DNA against degradation in a dose-dependent manner. Furthermore, our study shows that these effects are reversible and DNA can be released from the complexes. Release of DNA leads to restoration of gene expression and makes the DNA susceptible to degradation by Dnase. A highly charged polyelectrolyte, heparin, is needed to release DNA from dendrimers, while DNA complexed with CTAB dissociates with the non-ionic surfactant C12E5. Our results demonstrate the relation between DNA compaction by non-specific DNA-binding agents and gene expression and gene regulation can be achieved in vitro systems in a reliable dose-dependent and reversible manner. PMID:24671109

Ainalem, Marie-Louise; Bartles, Andrew; Muck, Joscha; Dias, Rita S; Carnerup, Anna M; Zink, Daniele; Nylander, Tommy

2014-01-01

273

Activation analysis of the compact ignition tokamak  

SciTech Connect

The US fusion program has completed the conceptual design of a compact tokamak device that achieves ignition. The high neutron wall loadings associated with this compact deuterium-tritium-burning device indicate that radiation-related issues may be significant considerations in the overall system design. Sufficient shielding will be requied for the radiation protection of both reactor components and occupational personnel. A close-in igloo shield has been designed around the periphery of the tokamak structure to permit personnel access into the test cell after shutdown and limit the total activation of the test cell components. This paper describes the conceptual design of the igloo shield system and discusses the major neutronic concerns related to the design of the Compact Ignition Tokamak.

Selcow, E.C.

1986-01-01

274

Powder and compaction characteristics of pregelatinized starches.  

PubMed

Pregelatinized starch is widely used as a pharmaceutical aid, especially as a filler-binder. It is known that the tableting performance of excipients could be affected by their source. The aim of this study was to evaluate the powder and tableting properties of pregelatinized starches obtained from yucca, corn and rice and compare those properties with those of Starch 1500. This material had the lowest particle size, and porosity and largest density and best flow. However, yucca starch and corn starch showed an irregular granule morphology, better compactibility and compressibility than Starch 1500. Their onset of plastic deformation and their strain rate sensitivity was comparable to that of Starch 1500. These two materials showed compact disintegration slower that Starch 1500. Conversely, rice starch showed a high elasticity, and friability, low compactibility, which are undesirable for direct compression. This study demonstrated the potential use of pregelatinized starches, especially those obtained from yucca and corn as direct compression filler-binders. PMID:22822539

Rojas, J; Uribe, Y; Zuluaga, A

2012-06-01

275

Anisotropic Compact stars with variable cosmological constant  

E-print Network

Recently the small value of the cosmological constant and its ability to accelerate the expansion of the Universe is of great interest. We discuss the possibility of forming of anisotropic compact stars from this cosmological constant as one of the competent candidates of dark energy. For this purpose we consider the analytical solution of Krori and Barua metric. We take the radial dependence of cosmological constant and check all the regularity conditions, TOV equations, stability and surface redshift of the compact stars. It has been shown as conclusion that this model is valid for any compact star and we have cited $4U 1820-30$ as a specific example of that kind of star.

Sk. Monowar Hossein; Farook Rahaman; Jayanta Naskar; Mehedi Kalam; Saibal Ray

2012-04-16

276

Gravitationally Focused Dark Matter around Compact Stars  

NASA Astrophysics Data System (ADS)

If dark matter self-annihilates then it may produce an observable signal when its density is high. The details depend on the intrinsic properties of dark matter and how it clusters in space. For example, the density profile of some dark matter candidates may rise steeply enough toward the Galactic Center that self-annihilation may produce detectable ?-ray emission. Here, we discuss the possibility that an annihilation signal arises near a compact object (e.g., neutron star or black hole) even when the density of dark matter in the neighborhood of the object is uniform. Gravitational focusing produces a local enhancement of density with a profile that falls off approximately as the inverse square-root of distance from the compact star. While geometric dilution may overwhelm the annihilation signal from this local enhancement, magnetic fields tied to the compact object can increase the signal's contrast relative to the background.

Bromley, Benjamin C.

2011-12-01

277

Hall MHD Equilibrium of Accelerated Compact Toroids  

NASA Astrophysics Data System (ADS)

We examine the structure and dynamics of the compact toroid's magnetic field. The compact toroid is dramatically accelerated by a large rail-gun Lorentz force density equal to j xB. We use magnetic data from the Compact Toroid Injection Experiment to answer the question of exactly where in the system j xB has nonzero values, and to what extent we can apply the standard model of force-free equilibrium. In particular we present a method of analysis of the magnetic field probe signals that allows direct comparison to the predictions of the Woltjer-Taylor force-free model and Turner's generalization of magnetic relaxation in the presence of a non-zero Hall term and fluid vorticity.

Howard, S. J.; Hwang, D. Q.; Horton, R. D.; Evans, R. W.; Brockington, S. J.

2007-11-01

278

Detecting compact binary coalescences with seedless clustering  

E-print Network

Compact binary coalescences are a promising source of gravitational waves for second-generation interferometric gravitational-wave detectors. Although matched filtering is the optimal search method for well-modeled systems, alternative detection strategies can be used to guard against theoretical errors (e.g., involving new physics and/or assumptions about spin/eccentricity) while providing a measure of redundancy. In previous work, we showed how "seedless clustering" can be used to detect long-lived gravitational-wave transients in both targeted and all-sky searches. In this paper, we apply seedless clustering to the problem of low-mass ($M_\\text{total}\\leq10M_\\odot$) compact binary coalescences for both spinning and eccentric systems. We show that seedless clustering provides a robust and computationally efficient method for detecting low-mass compact binaries.

Coughlin, Michael; Christensen, Nelson

2014-01-01

279

Detecting compact binary coalescences with seedless clustering  

NASA Astrophysics Data System (ADS)

Compact binary coalescences are a promising source of gravitational waves for second-generation interferometric gravitational-wave detectors. Although matched filtering is the optimal search method for well-modeled systems, alternative detection strategies can be used to guard against theoretical errors (e.g., involving new physics and/or assumptions about spin or eccentricity) while providing a measure of redundancy. In a previous paper, we showed how "seedless clustering" can be used to detect long-lived gravitational-wave transients in both targeted and all-sky searches. In this paper, we apply seedless clustering to the problem of low-mass (Mtotal?10M?) compact binary coalescences for both spinning and eccentric systems. We show that seedless clustering provides a robust and computationally efficient method for detecting low-mass compact binaries.

Coughlin, M.; Thrane, E.; Christensen, N.

2014-10-01

280

Compact Focal Plane Assembly for Planetary Science  

NASA Technical Reports Server (NTRS)

A compact radiometric focal plane assembly (FPA) has been designed in which the filters are individually co-registered over compact thermopile pixels. This allows for construction of an ultralightweight and compact radiometric instrument. The FPA also incorporates micromachined baffles in order to mitigate crosstalk and low-pass filter windows in order to eliminate high-frequency radiation. Compact metal mesh bandpass filters were fabricated for the far infrared (FIR) spectral range (17 to 100 microns), a game-changing technology for future planetary FIR instruments. This fabrication approach allows the dimensions of individual metal mesh filters to be tailored with better than 10- micron precision. In contrast, conventional compact filters employed in recent missions and in near-term instruments consist of large filter sheets manually cut into much smaller pieces, which is a much less precise and much more labor-intensive, expensive, and difficult process. Filter performance was validated by integrating them with thermopile arrays. Demonstration of the FPA will require the integration of two technologies. The first technology is compact, lightweight, robust against cryogenic thermal cycling, and radiation-hard micromachined bandpass filters. They consist of a copper mesh supported on a deep reactive ion-etched silicon frame. This design architecture is advantageous when constructing a lightweight and compact instrument because (1) the frame acts like a jig and facilitates filter integration with the FPA, (2) the frame can be designed so as to maximize the FPA field of view, (3) the frame can be simultaneously used as a baffle for mitigating crosstalk, and (4) micron-scale alignment features can be patterned so as to permit high-precision filter stacking and, consequently, increase the filter bandwidth and sharpen the out-of-band rolloff. The second technology consists of leveraging, from another project, compact and lightweight Bi0.87Sb0.13/Sb arrayed thermopiles. These detectors consist of 30-layer thermopiles deposited in series upon a silicon nitride membrane. At 300 K, the thermopile arrays are highly linear over many orders of magnitude of incident IR power, and have a reported specific detectivity that exceeds the requirements imposed on future mission concepts. The bandpass filter array board is integrated with a thermopile array board by mounting both boards on a machined aluminum jig.

Brown, Ari; Aslam, Shahid; Huang, Wei-Chung; Steptoe-Jackson, Rosalind

2013-01-01

281

Compact, Robust Chips Integrate Optical Functions  

NASA Technical Reports Server (NTRS)

Located in Bozeman, Montana, AdvR Inc. has been an active partner in NASA's Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) programs. Langley Research Center engineers partnered with AdvR through the SBIR program to develop new, compact, lightweight electro-optic components for remote sensing systems. While the primary customer for this technology will be NASA, AdvR foresees additional uses for its NASA-derived circuit chip in the fields of academic and industrial research anywhere that compact, low-cost, stabilized single-frequency lasers are needed.

2010-01-01

282

Nondestructive evaluation of compacted clayey soils  

NASA Astrophysics Data System (ADS)

Compacted clayey soils are analyzed using nondestructive testing methods. Ultrasonic testing and image analysis are used as nondestructive testing techniques. Tests were conducted on three clayey soils with low to high plasticities. The soils are compacted and then allowed to dry or subjected to wetting and drying cycles subsequent to compaction. Ultrasonic tests are performed to determine small strain elastic properties of soils during drying. Image analysis techniques are used to determine large strains and cracking behavior of soils during wetting and drying cycles. Finally, numerical methods are used to simulate large and small strain soil behavior. Ultrasonic testing can be used effectively to determine compaction characteristics of soils. Through transmission can be applicable in the laboratory or on recovered field samples while surface transmission can be used in the field. Variation of P-wave velocity is similar to variation of dry density for the test soils. Increasing compactive effort cause increases in measured wave velocity. Variations of elastic parameters during drying are investigated. More variation was observed for soils compacted with low compaction effort and high water contents. Five elastic parameters of cross-anisotropy are calculated from wave velocity measurements on cubical samples with oblique cuts. Constrained, Young's, and shear moduli increase, while Poisson's ratios decrease during drying. Starting with isotropy assumption, empirical formulas are used to calculate the shear moduli and results are compared with experimental shear modulus values obtained using the theory of elasticity. A new formulation is developed to compute shear modulus variation with saturation. Behavior of compacted clayey soils during wetting and drying was also investigated. High plasticity-fine grained soils tend to shrink and crack more during drying. Cracks of these soils tend to heal and close during wetting cycles. Cracking and healing are less for medium and low plasticity soils. Cracking is observed at relatively low suction levels for all soil types. Cracking is quantified using image analysis techniques. Finite element models are successfully used to make predictions on small strainwave propagation and fracture potential of soils. Transducer size has significant effect on surface arrangement arrival times and water content profile has significant effect on fracture potential.

Inci, Gokhan

283

Microchannel heat exchangers for charge minimization in air-cooled ammonia condensers and chillers  

Microsoft Academic Search

This paper presents experimental results from a prototype ammonia chiller with an air-cooled condenser and a plate evaporator. The main objectives were charge reduction and compactness of the system. The charge is reduced to 20g\\/kW (2.5oz\\/Ton). This is lower than any currently available air-cooled ammonia chiller on the market. The major contribution comes from use of microchannel aluminum tubes. Two

Pega Hrnjak; Andy D. Litch

2008-01-01

284

Photon: history, mass, charge  

E-print Network

The talk consists of three parts. ``History'' briefly describes the emergence and evolution of the concept of photon during the first two decades of the 20th century. ``Mass'' gives a short review of the literature on the upper limit of the photon's mass. ``Charge'' is a critical discussion of the existing interpretation of searches for photon charge. Schemes, in which all photons are charged, are grossly inconsistent. A model with three kinds of photons (positive, negative and neutral) seems at first sight to be more consistent, but turns out to have its own serious problems.

L. B. Okun

2006-02-03

285

taking charge : optimizing urban charging infrastructure for shared electric vehicles  

E-print Network

This thesis analyses the opportunities and constraints of deploying charging infrastructure for shared electric vehicles in urban environments. Existing electric vehicle charging infrastructure for privately owned vehicles ...

Subramani, Praveen

2012-01-01

286

Charged anisotropic matter with linear or nonlinear equation of state  

E-print Network

Ivanov pointed out substantial analytical difficulties associated with self-gravitating, static, isotropic fluid spheres when pressure explicitly depends on matter density. Simplification achieved with the introduction of electric charge were noticed as well. We deal with self-gravitating, charged, anisotropic fluids and get even more flexibility in solving the Einstein-Maxwell equations. In order to discuss analytical solutions we extend Krori and Barua's method to include pressure anisotropy and linear or non-linear equations of state. The field equations are reduced to a system of three algebraic equations for the anisotropic pressures as well as matter and electrostatic energy densities. Attention is paid to compact sources characterized by positive matter density and positive radial pressure. Arising solutions satisfy the energy conditions of general relativity. Spheres with vanishing net charge contain fluid elements with unbounded proper charge density located at the fluid-vacuum interface. Notably the electric force acting on these fluid elements is finite, although the acting electric field is zero. Net charges can be huge ($10^{19}\\,C$) and maximum electric field intensities are very large ($10^{23}-10^{24}\\,statvolt/cm$) even in the case of zero net charge. Inward-directed fluid forces caused by pressure anisotropy may allow equilibrium configurations with larger net charges and electric field intensities than those found in studies of charged isotropic fluids. Links of these results with charged strange quark stars as well as models of dark matter including massive charged particles are highlighted. The van der Waals equation of state leading to matter densities constrained by cubic polynomial equations is briefly considered. The fundamental question of stability is left open.

Victor Varela; Farook Rahaman; Saibal Ray; Koushik Chakraborty; Mehedi Kalam

2010-04-13

287

International aeronautical user charges  

E-print Network

Introduction: 1.1 BACKGROUND AND MOTIVATION Very few issues relating to the international air transportation industry are today as divisive as those pertaining to user charges imposed at international airports and enroute ...

Odoni, Amedeo R.

1985-01-01

288

Charged Schrodinger black holes  

E-print Network

We construct charged and rotating asymptotically Schrödinger black hole solutions of type IIB supergravity. We begin by obtaining a closed-form expression for the null Melvin twist of a broad class of type IIB backgrounds, ...

Adams, Allan

289

Primitive Virtual Negative Charge  

E-print Network

Physical fields, such as gravity and electromagnetic field, are interpreted as results from rearrangement of vacuum particles to get the equilibrium of net charge density and net mass density in 4-dimensional complex space. Then, both fields should interact to each other in that physical interaction is considered as a field-to-field interaction. Hence, Mass-Charge interaction is introduced with primitive-virtual negative charge defined for the mass. With the concept of Mass-Charge interaction electric equilibrium of the earth is discussed, especially about the electric field and magnetic field of the earth. For unsettled phenomena related with the earth's gravity, such as antigravity phenomenon, gravity anomalies during the solar eclipses, the connection between geomagnetic storms and earthquakes, etc., possible explanations are discussed.

Kiyoung Kim

2008-11-04

290

Primitive Virtual Negative Charge  

E-print Network

Physical fields, such as gravity and electromagnetic field, are interpreted as results from rearrangement of vacuum particles to get the equilibrium of net charge density and net mass density in 4-dimensional complex space. Then, both fields should interact to each other in that physical interaction is considered as a field-to-field interaction. Hence, Mass-Charge interaction is introduced with primitive-virtual negative charge defined for the mass. With the concept of Mass-Charge interaction electric equilibrium of the earth is discussed, especially about the electric field and magnetic field of the earth. For unsettled phenomena related with the earth's gravity, such as antigravity phenomenon, gravity anomalies during the solar eclipses, the connection between geomagnetic storms and earthquakes, etc., possible explanations are discussed.

Kim, Kiyoung

2008-01-01

291

Gauge Charges from Supergravity  

E-print Network

Some recent results in the study of four dimensional supergravity flux compactifications are reviewed, discussing in particular the role of torsion on the compactification manifold in generating gauge charges for the effective four dimensional theories.

L. Andrianopoli

2005-11-04

292

Compact 340 GHz Receiver Front-Ends  

Microsoft Academic Search

A compact 340 GHz room temperature receiver front-end has been developed consisting of a subharmonic Schottky diode mixer module with an integrated LNA. A novel sideband separation topology has been evaluated by using a pair of the developed mixers interconnected by external waveguide branch guide coupler hybrids for the LO and RF feedings and coaxial IF hybrids, measuring sideband suppression

Peter Sobis; Tomas Bryllert; A. Olsen; J. Vukusic; V. Drakinskiy; S. Cherednichenko; A. Emrich; J. Stake

2009-01-01

293

Neurogenetic optimization of micro compact heat exchanger  

Microsoft Academic Search

Purpose – This paper seeks to introduce an optimization method for maximizing the effectiveness of the micro compact heat exchanger (MHE) under various geometrical parameters. Design\\/methodology\\/approach – Optimization is realized using the neuro-genetic methodology which combines the application of artificial neural network (ANN) together with genetic algorithms (GA). The analyses are divided into two main sections; the first being the

H. W. Lee; Y. J. Teng; I. A. Azid; K. N. Seetharamu

2007-01-01

294

Compact microwave cavity for hydrogen atomic clock  

NASA Technical Reports Server (NTRS)

A summary is presented that introduces the compact microwave cavity used in the hydrogen atomic clock. Special emphasis is placed on derivation of theoretical calculating equations of main parameters of the microwave cavity. A brief description is given of several methods for discriminating the oscillating modes. Experimental data and respective calculated values are also presented.

Zhang, Dejun; Zhang, Yan; Fu, Yigen; Zhang, Yanjun

1992-01-01

295

Geometry of compact tubes and protein structures  

E-print Network

Proteins form a very important class of polymers. In spite of major advances in the understanding of polymer science, the protein problem has remained largely unsolved. Here, we show that a polymer chain viewed as a tube not only captures the well-known characteristics of polymers and their phases but also provides a natural explanation for many of the key features of protein behavior. There are two natural length scales associated with a tube subject to compaction -- the thickness of the tube and the range of the attractive interactions. For short tubes, when these length scales become comparable, one obtains marginally compact structures, which are relatively few in number compared to those in the generic compact phase of polymers. The motifs associated with the structures in this new phase include helices, hairpins and sheets. We suggest that Nature has selected this phase for the structures of proteins because of its many advantages including the few candidate strucures, the ability to squeeze the water out from the hydrophobic core and the flexibility and versatility associated with being marginally compact. Our results provide a framework for understanding the common features of all proteins.

J. R. Banavar; A. Flammini; D. Marenduzzo; A. Maritan; A. Trovato

2002-03-25

296

Riggings of locally compact abelian groups  

E-print Network

We obtain a set of generalized eigenvectors that provides a generalized spectral decomposition for a given unitary representation of a commutative, locally compact topological group. These generalized eigenvectors are functionals belonging to the dual space of a rigging on the space of square integrable functions on the character group. These riggings are obtained through suitable spectral measure spaces.

M. Gadella; F. Gomez; S. Wickramasekara

2007-04-12

297

Compact Rewritings for Existential Rules Michael Thomazo  

E-print Network

Compact Rewritings for Existential Rules Micha¨el Thomazo University of Montpellier France thomazo- main research. In this paper, we consider ontolo- gies described by existential rules (also known are a restricted form of positive existential formulas, and compute sound and complete rewritings, which are union

Paris-Sud XI, Université de

298

Compact Tactile Sensors for Robot Fingers  

NASA Technical Reports Server (NTRS)

Compact transducer arrays that measure spatial distributions of force or pressure have been demonstrated as prototypes of tactile sensors to be mounted on fingers and palms of dexterous robot hands. The pressure- or force-distribution feedback provided by these sensors is essential for the further development and implementation of robot-control capabilities for humanlike grasping and manipulation.

Martin, Toby B.; Lussy, David; Gaudiano, Frank; Hulse, Aaron; Diftler, Myron A.; Rodriguez, Dagoberto; Bielski, Paul; Butzer, Melisa

2004-01-01

299

A Global Compact to End Poverty  

E-print Network

A Global Compact to End Poverty Jeffrey Sachs on stabilisation, transition and weapons of mass progress. We can realistically envision a world without extreme poverty by the year 2025 because. Sachs, The End of Poverty, 2005. WORLD ECONOMICS · Vol. 6 · No. 4 · October­December 2005 11 Jeffrey D

300

Dynamic error field analysis for compact synchrotron  

SciTech Connect

Dynamic error fields due to eddy currents induced in vacuum chambers which are located in bending and quadrupole magnets of the compact synchrotron luna during acceleration are numerically analyzed by Incanet. Especially, the effects of the dynamic error fields on a beam orbit are quantitatively evaluated as a function of speed of acceleration.

Uesaka, M.; Takahashi, M.; Ida, M.; Marushita, M.; Mandai, S.; Hoshi, Y. (Ishikawajima-Harima Heavy Industries Co., Ltd., Marunouchi, Tokyo 100 (JP))

1990-03-01

301

Hermite Functions on Compact Lie Groups, II  

Microsoft Academic Search

The usual formula for Hermite polynomials on Rd is extended to a compact Lie group G, yielding an isometry of L2(G, p1), where p1 is the heat kernel measure at time one, with a natural completion of the universal enveloping algebra of G. The existence of such an isometry was first established by L. Gross; here we present a simplified

O. Hijab

1995-01-01

302

Workability in forging of powder metallurgy compacts  

Microsoft Academic Search

The power metallurgy (PM) technique is now applied widely to many industries and materials. To obtain more reliable PM products, many secondary processes are applied to PM preforms. The problem of deformation and fracture of PM preforms still needs a considerable amount of investigation.In this work, the effect of the relative density on the forming limit of PM compacts in

M. Abdel-Rahman; M. N. El-Sheikh

1995-01-01

303

The Compact Course: A Curricular Innovation.  

ERIC Educational Resources Information Center

A three-year curriculum of "Compact Courses" which was introduced in a secondary school in England is described here. The objectives of each course are terminal; the courses have no fixed length or pattern. The method adopted is that best suited to the teacher in view of the terminal objective. During the first 2 years, students take eight…

Cross, David

304

Compactly encoding unstructured inputs with differential compression  

Microsoft Academic Search

The subject of this article is differential compression, the algorithmic task of finding common strings between versions of data and using them to encode one version compactly by describing it as a set of changes from its companion. A main goal of this work is to present new differencing algorithms that (i) operate at a fine granularity (the atomic unit

Miklos Ajtai; Randal C. Burns; Ronald Fagin; Darrell D. E. Long; Larry J. Stockmeyer

2002-01-01

305

Compact Hydraulic Excavator and Support Unit  

NASA Technical Reports Server (NTRS)

Continuous-coal-mining machine maneuverable. Hydraulic coal excavator combined with chock, or roof-support structure, in self-contained unit that moves itself forward as it removes coal from seam. Unlike previous such units, new machine compact enough to be easily maneuverable; even makes small-radius right-angle turns.

Lewis, E. V.

1985-01-01

306

The Evolution of Compact Binary Star Systems  

E-print Network

We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs) within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA). Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars -- compact binaries in which the Roche lobe is filled by another WD or a low-mass partia...

Postnov, K; Postnov, Konstantin; Yungelson, Lev

2007-01-01

307

The Evolution of Compact Binary Star Systems  

E-print Network

We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs) within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA). Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars -- compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.

Konstantin Postnov; Lev Yungelson

2007-01-03

308

FAULT PREDICTIVE CONTROL OF COMPACT DISK PLAYERS  

E-print Network

FAULT PREDICTIVE CONTROL OF COMPACT DISK PLAYERS Peter Fogh Odgaard Mladen Victor Wickerhauser playing certain discs with surface faults like scratches and fingerprints. The problem is to be found in an other publications of the first author. This scheme is based on an assumption that the surface faults do

Wickerhauser, M. Victor

309

Indoor radon detected by compact discs  

Microsoft Academic Search

An approach for a precise retrospective assessment of the indoor radon exposure using commercial compact discs (CDs) is proposed. It is based on the remarkable radon absorption and ? track-etch properties of polycarbonate — the basic material of the CDs. The experimental results indicate that the useful range of this approach is able to cover practically the entire range of

D. Pressyanov; J. Buysse; A. Van Deynse; A. Poffijn; G. Meesen

2001-01-01

310

Robust control of a compact disc player  

Microsoft Academic Search

The design of robust controllers for a compact disc mechanism is considered. Using ? synthesis, a controller has been designed for good track-following. The design problem involves time-domain constraints on signals and robustness requirements for norm-bounded structured plant uncertainty. It is shown that by using weighting functions in the ? framework this problem can be solved, but at the cost

Maarten Steinbuch; Gerrit Schootstra; Okko H. Bosgra

1992-01-01

311

Compact Disc Cataloging Product User Survey.  

ERIC Educational Resources Information Center

In late 1988, a compact disc cataloging product was introduced to the library market. In order to learn more about the needs of current users, a survey was developed to include questions concerning software features and operations, software enhancements, bibliographic and authority subsets, and hardware issues. This study was conducted among all…

Whitehair, David E.

312

Molecular screening on a compact disc  

Microsoft Academic Search

A method is described to screen the recognition between small molecule ligands and biomolecules using a conventional compact disc (CD) player. A procedure was developed to attach ligands to the reading face of a CD by activating the terminus of polycarbonate, a common polymer composite within the reading face of a CD. Terminal residues of the polycarbonate surface 1 were

James J. La Clair; Michael D. Burkart

2003-01-01

313

Compact, Lightweight Servo-Controllable Brakes  

NASA Technical Reports Server (NTRS)

Compact, lightweight servo-controllable brakes capable of high torques are being developed for incorporation into robot joints. A brake of this type is based partly on the capstan effect of tension elements. In a brake of the type under development, a controllable intermediate state of torque is reached through on/off switching at a high frequency.

Lovchik, Christopher S.; Townsend, William; Guertin, Jeffrey; Matsuoka, Yoky

2010-01-01

314

Compact Kac algebras and commuting squares  

Microsoft Academic Search

We consider commuting squares of finite dimensional von Neumann algebras having the algebra of complex numbers in the lower left corner. Examples include the vertex models, the spin models (in the sense of subfactor theory) and the commuting squares associated to finite dimensional Kac algebras. To any such commuting square we associate a compact Kac algebra and we compute the

Teodor Banica

1999-01-01

315

Compact fast analyzer of rotary cuvette type  

Microsoft Academic Search

A compact fast analyzer of the rotary cuvette type is provided for simultaneously determining concentrations in a multiplicity of discrete samples using either absorbance or fluorescence measurement techniques. A rigid, generally rectangular frame defines optical passageways for the absorbance and fluorescence measurement systems. The frame also serves as a mounting structure for various optical components as well as for the

Thacker; Louis H

1976-01-01

316

Modeling of spacecraft charging  

NASA Technical Reports Server (NTRS)

Three types of modeling of spacecraft charging are discussed: statistical models, parametric models, and physical models. Local time dependence of circuit upset for DoD and communication satellites, and electron current to a sphere with an assumed Debye potential distribution are presented. Four regions were involved in spacecraft charging: (1) undisturbed plasma, (2) plasma sheath region, (3) spacecraft surface, and (4) spacecraft equivalent circuit.

Whipple, E. C., Jr.

1977-01-01

317

FABRICATION OF URANIUM OXYCARBIDE KERNELS AND COMPACTS FOR HTR FUEL  

SciTech Connect

As part of the program to demonstrate tristructural isotropic (TRISO)-coated fuel for the Next Generation Nuclear Plant (NGNP), Advanced Gas Reactor (AGR) fuel is being irradiation tested in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL). This testing has led to improved kernel fabrication techniques, the formation of TRISO fuel particles, and upgrades to the overcoating, compaction, and heat treatment processes. Combined, these improvements provide a fuel manufacturing process that meets the stringent requirements associated with testing in the AGR experimentation program. Researchers at Idaho National Laboratory (INL) are working in conjunction with a team from Babcock and Wilcox (B&W) and Oak Ridge National Laboratory (ORNL) to (a) improve the quality of uranium oxycarbide (UCO) fuel kernels, (b) deposit TRISO layers to produce a fuel that meets or exceeds the standard developed by German researches in the 1980s, and (c) develop a process to overcoat TRISO particles with the same matrix material, but applies it with water using equipment previously and successfully employed in the pharmaceutical industry. A primary goal of this work is to simplify the process, making it more robust and repeatable while relying less on operator technique than prior overcoating efforts. A secondary goal is to improve first-pass yields to greater than 95% through the use of established technology and equipment. In the first test, called “AGR-1,” graphite compacts containing approximately 300,000 coated particles were irradiated from December 2006 to November 2009. The AGR-1 fuel was designed to closely replicate many of the properties of German TRISO-coated particles, thought to be important for good fuel performance. No release of gaseous fission product, indicative of particle coating failure, was detected in the nearly 3-year irradiation to a peak burn up of 19.6% at a time-average temperature of 1038–1121°C. Before fabricating AGR-2 fuel, each fabrication process was improved and changed. Changes to the kernel fabrication process included replacing the carbon black powder feed with a surface-modified carbon slurry and shortening the sintering schedule. AGR-2 TRISO particles were produced in a 6-inch diameter coater using a charge size about 21-times that of the 2-inch diameter coater used to coat AGR-1 particles. The compacting process was changed to increase matrix density and throughput by increasing the temperature and pressure of pressing and using a different type of press. AGR-2 fuel began irradiation in the ATR in late spring 2010.

Dr. Jeffrey A. Phillips; Eric L. Shaber; Scott G. Nagley

2012-10-01

318

Investigation of HMA compactability using GPR technique  

NASA Astrophysics Data System (ADS)

In-situ field density is often regarded as one of the most important controls used to ensure that an asphalt pavement being placed is of high quality. The achieved density results from the effectiveness of the applied compaction mode on the Hot Mix Asphalt (HMA) layer. It is worthwhile mentioning that the proper compaction of HMA increases pavement fatigue life, decreases the amount of permanent deformation or rutting, reduces the amount of oxidation or aging, decreases moisture damage or stripping, increases strength and internal stability, and may decrease slightly the amount of low-temperature cracking that may occur in the mix. Conventionally, the HMA density in the field is assessed by direct destructive methods, including through the cutting of samples or drilling cores. These methods are characterized by a high accuracy, although they are intrusive and time consuming. In addition, they provide local information, i.e. information only for the exact test location. To overcome these limitations, the use of non-intrusive techniques is often recommended. The Ground Penetrating Radar (GPR) technique is an example of a non-intrusive technique that has been increasingly used for pavement investigations over the years. GPR technology is practical and application-oriented with the overall design concept, as well as the hardware, usually dependent on the target type and the material composing the target and its surroundings. As the sophistication of operating practices increases, the technology matures and GPR becomes an intelligent sensor system. The intelligent sensing deals with the expanded range of GPR applications in pavements such as determining layer thickness, detecting subsurface distresses, estimating moisture content, detecting voids and others. In addition, the practice of using GPR to predict in-situ field density of compacted asphalt mixture material is still under development and research; however the related research findings seem to be promising. Actually, the prediction is not regulated by any standards or specifications, although the practice is considered to be workable. In view of the above, an extensive experiment was carried out in both the laboratory and the field based on a trial asphalt pavement section under construction. In the laboratory, the study focused on the estimation of the density of HMA specimens achieved through three different roller compaction modes (static, vibratory and a combination of both) targeted to simulate field compaction and assess the asphalt mix compactability. In the field, the different compaction modes were successively implemented on three subsections of the trial pavement section. Along each subsection, GPR data was collected in order to determine the new material's dielectric properties and based on that, to predict its density using proper algorithm. Thus, cores were extracted to be used as ground truth data. The comparison of the new asphalt material compactability as obtained from the laboratory specimens, the predictions based on GPR data and the field cores provided useful information that facilitated the selection of the most effective compaction mode yielding the proper compaction degree in the field. This work benefited from networking activities carried out within the EU funded COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar."

Plati, Christina; Georgiou, Panos; Loizos, Andreas

2014-05-01

319

Stability of flux vacua in the presence of charged black holes  

Microsoft Academic Search

In this letter we consider a charged black hole in a flux compactification of type IIB string theory. Both the black hole and the fluxes will induce potentials for the complex structure moduli. We choose the compact dimensions to be described locally by a deformed conifold, creating a large hierarchy. We demonstrate that the presence of a black hole typically

Ulf H. Danielsson; Niklas Johansson; Magdalena Larfors

2006-01-01

320

Spacecraft Habitation Systems, Water Recovery and Waste Active Charged Particle and Neutron Radiation Measurement  

E-print Network

SBIR SBIR 62 63 I Spacecraft Habitation Systems, Water Recovery and Waste Management Active Charged, High Output Plastic Melt Waste Compactor (HEHO-PMWC) is a trash dewatering and volume reduction system that uses heat melt compaction to remove nearly 100% of water from trash and reduce the volume by up to 11

321

Fast particles in a steady-state compact FNS and compact ST reactor  

NASA Astrophysics Data System (ADS)

This paper presents results of studies of fast particles (ions and alpha particles) in a steady-state compact fusion neutron source (CFNS) and a compact spherical tokamak (ST) reactor with Monte-Carlo and Fokker–Planck codes. Full-orbit simulations of fast particle physics indicate that a compact high field ST can be optimized for energy production by a reduction of the necessary (for the alpha containment) plasma current compared with predictions made using simple analytic expressions, or using guiding centre approximation in a numerical code. Alpha particle losses may result in significant heating and erosion of the first wall, so such losses for an ST pilot plant have been calculated and total and peak wall loads dependence on the plasma current has been studied. The problem of dilution has been investigated and results for compact and big size devices are compared.

Gryaznevich, M. P.; Nicolai, A.; Buxton, P.

2014-10-01

322

The Dynamic Compact Control Language: A compact marshalling scheme for acoustic communications  

E-print Network

The Dynamic Compact Control Language (DCCL) extends the ubiquitous Extensible Markup Language (XML) to provide a structure for defining very short messages comprised of bounded basic variable types, suitable for transmission ...

Schneider, Toby Edwin

323

16 CFR Appendix C1 to Part 305 - Compact Dishwashers  

Code of Federal Regulations, 2010 CFR

... Compact Dishwashers C1 Appendix C1 to Part 305 Commercial Practices FEDERAL TRADE COMMISSION...CONSERVATION ACT (âAPPLIANCE LABELING RULEâ) Pt. 305, App. C1 Appendix C1 to Part 305—Compact Dishwashers Range Information...

2010-01-01

324

Fundamental building blocks for a compact optoelectronic neural network processor  

E-print Network

The focus of this thesis is interconnects within the Compact Optoelectronic Neural Network Processor. The goal of the Compact Optoelectronic Neural Network Processor Project (CONNPP) is to build a small, rugged neural ...

Ruedlinger, Benjamin Franklin, 1976-

2003-01-01

325

Compact modeling of circuits and devices in Verilog-A  

E-print Network

The compact model of a circuit or device is a system of linear and/or nonlinear differential equations that effectively models the behavior of the circuit or device. Compact modeling plays a critical role in circuit ...

Mysore, Omar

2012-01-01

326

Tight and Compact MIP Formulation of Configuration-Based ...  

E-print Network

IEEE TRANSACTIONS ON POWER SYSTEMS (working paper). 1. Tight and Compact ... times because it is simultaneously tight and compact in com- parison with .... The tightness of a MIP formulation defines the search space that the solver ...

2014-09-20

327

Identity Crises and Strong Compactness II: Strong Cardinals  

E-print Network

the general field of "identity crisis studies", there has been additional, extensive resear* *ch done Identity Crises and Strong Compactness II: Strong Cardinals of Magidor, that the class of strongly compact cardinals can assume yet another identity. Specifically, we

Cummings, James

328

Highly Charged Ions in Rare Earth Permanent Magnet Penning Traps  

NASA Astrophysics Data System (ADS)

A newly constructed apparatus at the United States National Institute of Standards and Technology (NIST) is designed for the isolation, manipulation, and study of highly charged ions. Highly charged ions are produced in the NIST electron-beam ion trap (EBIT), extracted through a beamline that selects a single mass/charge species, then captured in a compact Penning trap. The magnetic field of the trap is generated by cylindrical NdFeB permanent magnets integrated into its electrodes. In a room-temperature prototype trap with a single NdFeB magnet, species including Ne10+ and N7+ were confined with storage times of order 1 second, showing the potential of this setup for manipulation and spectroscopy of highly charged ions in a controlled environment. Ion capture has since been demonstrated with similar storage times in a more-elaborate Penning trap that integrates two coaxial NdFeB magnets for improved B-field homogeneity. Ongoing experiments utilize a second-generation apparatus that incorporates this two-magnet Penning trap along with a fast time-of-flight MCP detector capable of resolving the charge-state evolution of trapped ions. Holes in the two-magnet Penning trap ring electrode allow for optical and atomic beam access. Possible applications include spectroscopic studies of one-electron ions in Rydberg states, as well as highly charged ions of interest in atomic physics, metrology, astrophysics, and plasma diagnostics.

Guise, Nicholas D.; Brewer, Samuel M.; Tan, Joseph N.

329

A laboratory investigation of vibratory compaction of dry soils  

E-print Network

II. ? Notation APPENDIX III. ? Letters of Release for Copyrighted 91 92 93 96 Material 98 VITA 103 LIST OF TABLES Tab le Page 1. Compaction Data on a Lean Clay Using Sheepsfoot and Pneumatic-Tired Types of Rollers 16 2. Compaction Data... on Four British Soils Compacted by Five Different Types of Rollers 17 3. Recommended Compactors for Various Soil Types 4. Granular Soils ? Classification Test Results 18 28 LIST Of FIGURES Figure Page I, A Typical Laboratory Compaction Curve...

Webster, Cecil Ray

2012-06-07

330

Design study status of compact containment BWR  

SciTech Connect

The reactor concept considered in this paper has a relatively mid/small power output, a compact containment and a simplified BWR configuration with comprehensive safety features. The Japan Atomic Power Company has been taking initiative in developing the concept of the Compact Containment Boiling Water Reactor (CCR). The CCR., which is being developed with matured BWR technologies together with innovative systems/components, is expected to prove attractive in the world energy markets due to its flexibility in regard to energy demands and site conditions, its high potential for reducing investment risk and its safety features facilitating public acceptance. The flexibility is achieved by CCR's relatively mid/small power output of 400 MWe class and capability of long operating cycle (refueling intervals). CCR is expected to be attractive from view point of investment due to its simplification/innovation in design such as natural circulation core cooling with the bottom located short core, upper entry control rod drives (CRDs) and simplified safety system with high pressure resistible containment concept. The natural circulation core eliminates recirculation pumps and the maintenance of such pumps. The upper entry CRDs enable a simplified safety system followed by in-vessel retention (IVR) capability with the compact primary containment vessel (PCV). The safety features mainly consist of large water inventory above the core without large penetration of RPV below the top of the core height, passive cooling system by isolation condenser (IC). The large inventory increases the system response time in the case of design-base accidents, including loss of coolant accidents. The IC suppresses PCV pressure by steam condensation without any AC power. Cooling the molten core inside the RPV if the core should be damaged by loss of core coolability could attain the IVR. Further core design study has been carried out taking into account compact reactor size and reduction of fuel bundles and CRDs. The feasibility of CCR safety system has been confirmed by LOCA analysis. The Compact Containment Boiling Water Reactor (CCR) has the possibility realizing both an economical and a safe small reactor through application of a simplified system and compact PCV. (authors)

Heki, H.; Nakamaru, M.; Kuroki, M.; Kojima, Y. [System Design and Engineering Department, Toshiba Corporation, 8, Shinsugita-cho, Isogo-ku, Yokohama 235-85 (Japan); Arai, K.; Tahara, M. [Power and Industrial Systems Research and Development Center, Toshiba Corporation, 8, Shinsugita-cho, Isogo-ku, Yokohama 235-85 (Japan); Hoshi, T. [The Japan Atomic Power Company, 1-1, Kandamitoshiro-cho, Chiyoda-ku 101-0053 (Japan)

2006-07-01

331

Taming Highly Charged Radioisotopes  

NASA Astrophysics Data System (ADS)

The precise and accurate mass of short-lived radioisotopes is a very important parameter in physics. Contribution to the improvement of nuclear models, metrological standard fixing and tests of the unitarity of the Caibbibo-Kobayashi-Maskawa (CKM) matrix are a few examples where the mass value plays a major role. TRIUMF's ion trap for atomic and nuclear physics (TITAN) is a unique facility of three online ion traps that enables the mass measurement of short-lived isotopes with high precision (˜10-8). At present TITAN's electron beam ion trap (EBIT) increases the charge state to increase the precision, but there is no facility to significantly reduce the energy spread introduced by the charge breeding process. The precision of the measured mass of radioisotopes is linearly dependent on the charge state while the energy spread of the charged radioisotopes affects the precision adversely. To boost the precision level of mass measurement at TITAN without loosing too many ions, a cooler Penning trap (CPET) is being developed. CPET is designed to use either positively (proton) or negatively (electron) charged particles to reduce the energy spread via sympathetic cooling. Off-line setup of CPET is complete. Details of the working principles and updates are presented

Chowdhury, Usman; Eberhardt, Benjamin; Jang, Fuluni; Schultz, Brad; Simon, Vanessa; Delheij, Paul; Dilling, Jens; Gwinner, Gerald

2012-10-01

332

Charge Transfer Reactions  

NASA Astrophysics Data System (ADS)

Charge transfer, or charge exchange, describes a process in which an ion takes one or more electrons from another atom. Investigations of this fundamental process have accompanied atomic physics from its very beginning, and have been extended to astrophysical scenarios already many decades ago. Yet one important aspect of this process, i.e. its high efficiency in generating X-rays, was only revealed in 1996, when comets were discovered as a new class of X-ray sources. This finding has opened up an entirely new field of X-ray studies, with great impact due to the richness of the underlying atomic physics, as the X-rays are not generated by hot electrons, but by ions picking up electrons from cold gas. While comets still represent the best astrophysical laboratory for investigating the physics of charge transfer, various studies have already spotted a variety of other astrophysical locations, within and beyond our solar system, where X-rays may be generated by this process. They range from planetary atmospheres, the heliosphere, the interstellar medium and stars to galaxies and clusters of galaxies, where charge transfer may even be observationally linked to dark matter. This review attempts to put the various aspects of the study of charge transfer reactions into a broader historical context, with special emphasis on X-ray astrophysics, where the discovery of cometary X-ray emission may have stimulated a novel look at our universe.

Dennerl, Konrad

2010-12-01

333

Thermodynamic analysis of compact formation; compaction, unloading, and ejection. II. Mechanical energy (work) and thermal energy (heat) determinations of compact unloading and ejection.  

PubMed

A compaction calorimeter, previously described (DeCrosta, M.T., Schwartz, J.B., Wigent, J.B., Marshall, K., 2000. Thermodynamic analysis of compact formation; compaction, unloading, and ejection. I. Design and development of a compaction calorimeter and mechanical and thermal energy determinations of powder compaction. Int. J. Pharm. 198, 113--134), was utilized to evaluate the thermodynamics of the unloading and ejection of compacts of Avicel pH102, Emcompress, Fast-Flo #316, Starch 1500, and acetaminophen (APAP). A constant strain waveform, applied by a compaction simulator, enabled the separate thermodynamic evaluation of unloading from compaction. The brittle materials, Fast-Flo #316 and Emcompress, displayed the most unloading work, and the plastic/self-lubricating materials, Avicel and Starch 1500, displayed the least. Unloading heat values were negative for all materials, except APAP. APAP's positive heat values indicated the breaking of bonds during unloading as a result of its highly elastic nature. Positive internal energy changes of unloading, which indicate the net breaking of bonds, were observed for APAP and Emcompress over the compaction forces tested. Negative energy changes for Starch 1500, Fast-Flo #316, and Avicel became positive with increasing compaction forces. Ejection work increased with increasing compaction force for the brittle materials, whereas smaller ejection work values for Avicel, Starch 1500, and APAP remained constant. Increasing negative heat values as a function of compaction force were observed for Fast-Flo #316 and Emcompress. Negative internal energy values for ejection were observed for Fast-Flo #316 and Emcompress, which indicates net bond formation as a result of high shear of the compact with the die wall. Internal energy changes for Starch 1500, Avicel, and APAP, were approximately zero, indicating the absence of net bonding or bond formation during the process. PMID:11165093

DeCrosta, M T; Schwartz, J B; Wigent, R J; Marshall, K

2001-02-01

334

Multifunctional graded index TiO2 compact layer for performance enhancement in dye sensitized solar cell  

NASA Astrophysics Data System (ADS)

A specially tailored index TiO2 compact layer (arc-TiO2) has been successfully deposited to serve as photoanode of a dye-sensitized solar cell (DSSC) by radio-frequency magnetron sputtering. The employment of the TiO2 compact layer in the DSSC was systematically investigated by means of UV-absorption spectra, incident photon to current efficiency (IPCE), open-circuit voltage decay (OCVD) and electrochemical impedance spectroscopy (EIS). The higher and red-shifted transmittance spectra of the ITO/arc-TiO2 electrode mimic the IPCE spectra of the DSSC, in a specific wavelength region. Furthermore, the blue-shift of the UV-absorption spectra and lower R1 value obtained from EIS measurements implied the decrease of the charge interfacial resistance, and this consequently facilitates the charge transport from the nanocrystalline-TiO2 to the ITO. The integrated effects of the arc-TiO2 compact layer originate the remarkable improvement in this type of DSSC applications. As a result, the arc-TiO2-based DSSC showed higher conversion efficiency of about 4.38%, representing almost 53% increment compared to bare ITO cell. This work also discuss the fundamental insight of the compact layer that determines the origin of such improvement in the DSSC performance.

Abdullah, M. H.; Rusop, M.

2013-11-01

335

Nanoparticle coagulation in fractionally charged and charge fluctuating dusty plasmas  

SciTech Connect

The kinetics of nanoparticle coagulation has been studied in fractionally charged and charge fluctuating dusty plasmas. The coagulation occurs when the mutual collision frequency among nanoparticles exceeds their charging and decharging/neutralization frequency. Interestingly, the coagulation is suppressed while a fraction (several percent) of nanoparticles are negatively charged in a plasma, in which stochastic charging plays an important role. A model is developed to predict a phase diagram of the coagulation and its suppression.

Nunomura, Shota; Kondo, Michio [Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan); Shiratani, Masaharu; Koga, Kazunori; Watanabe, Yukio [Department of Electronics, Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka 819-0395 (Japan)

2008-08-15

336

3-DIMENSIONAL COMPACT DISC (CD) MICROFLUIDIC PLATFORM Presented to the  

E-print Network

3-DIMENSIONAL COMPACT DISC (CD) MICROFLUIDIC PLATFORM _______________ A Thesis Presented OF THE THESIS 3-Dimensional Compact Disc (CD) Microfluidic Platform by Nitin Edmund Harwood Master of Science in a compact disc (CD) microfluidics platform involving two or more layers. The traditional 2-Dimensional

Kassegne, Samuel Kinde

337

Adaptive Feature Based Control of Compact Disk Players  

Microsoft Academic Search

Many have experienced the problem that their Compact Disc players have difficulties playing Compact Discs with surface faults like scratches and fingerprints. The cause of this is due to the two servo control loops used to keep the Optical Pick-up Unit focused and radially on the information track of the Compact Disc. The problem is to design servo controllers which

P. F. Odgaard; J. Stoustrup; E. Vidal

2005-01-01

338

Effect of die wall lubrication on warm compaction powder metallurgy  

Microsoft Academic Search

Die wall lubrication was applied on warm compaction powder metallurgy in the hope to reduce the concentration level of the admixed lubricant, since lubricant is harmful to the mechanical properties of the sintered material. Iron-based samples were prepared by die wall lubricated warm compaction at 135 and 175°C, using polytetrafluoroethylene (PTFE) emulsion as the die wall lubricant. Compacting pressures of

Y. Y Li; T. L Ngai; D. T Zhang; Y Long; W Xia

2002-01-01

339

CRIGOS: a compact robot for image-guided orthopedic surgery  

Microsoft Academic Search

The CRIGOS (compact robot for image-guided orthopedic surgery) project was set up for the development of a compact surgical robot system for image-guided orthopedic surgery based on user requirements. The modular system comprises a compact parallel robot and a software system for planning of surgical interventions and for supervision of the robotic device. Because it is not sufficient to consider

Guido Brandt; Andreas Zimolong; Lionel Carrat; Philippe Merloz; Hans-Walter Staudte; Stéphane Lavallée; Klaus Radermacher; Günther Rau

1999-01-01

340

Soil Quality Information Sheet Rangeland Soil Quality--Compaction  

E-print Network

Conservation Service May 2001 Rangeland Sheet 4 What is compaction? Soil compaction occurs when moist or wet soil density and the decreased pore space limit water infiltration, percolation, and storage; plant growth; or nutrient cycling. Water movement and storage.--Compaction reduces the capacity of the soil

341

BROWNIAN PROCESSES FOR MONTE CARLO INTEGRATION ON COMPACT LIE GROUPS  

E-print Network

BROWNIAN PROCESSES FOR MONTE CARLO INTEGRATION ON COMPACT LIE GROUPS S. SAID, The University for the evaluation of integrals of smooth functions defined on compact Lie groups. The approach is based on the ergodic property of Brownian processes in compact Lie groups. The paper provides an elementary proof

Manton, Jonathan

342

FEATURE BASED HANDLING OF SURFACE FAULTS IN COMPACT DISC PLAYERS  

E-print Network

FEATURE BASED HANDLING OF SURFACE FAULTS IN COMPACT DISC PLAYERS Peter Fogh Odgaard ,1 Jakob & Olufsen A/S, Peter Bangs Vej 15, DK-7600 Struer, Denmark Abstract: Compact Disc players have been. However, there are still problems with playing Compact Discs related to surface faults like scratches

Wickerhauser, M. Victor

343

Using the Shannon Sampling Theorem to Design Compact Discs  

E-print Network

Using the Shannon Sampling Theorem to Design Compact Discs Susan E. Kelly Abstract The Shannon this theory, music can be stored on a compact disc by recording the function's amplitude at points sampled with students at both of these levels. Have you ever wondered how music is stored on a compact disc

Kelly, Susan

344

Compact Discs--A Revolution in the Making.  

ERIC Educational Resources Information Center

Discusses the theory behind the system of the compact disc (encoding process, decoding system), its potential for growth, and its possible impact on the way libraries handle sound recordings. Guidelines for purchase of compact disc equipment are given. A comparison of compact discs and long-playing records is appended. (37 references) (EJS)

Ridgway, Jim

1986-01-01

345

Investigations on Forced Convection in Compact Passages with Surface Irregularities  

Microsoft Academic Search

Two-dimensional, fully developed, convective heat transfer in compact passages is investigated numerically, incorporating the effects of the surface irregularities, to analyze the influence of these irregularities on fluid flow and heat transfer. This analysis helps to bring out the differences in the performance evaluation if regular cross-sections are assumed in analyzing compact and mini channels. Forced convection in compact passages

Binoy Baby; Choondal B. Sobhan

2012-01-01

346

A compact streak camera for 150 fs time resolved measurement of bright pulses in ultrafast electron diffraction.  

PubMed

We have developed a compact streak camera suitable for measuring the duration of highly charged subrelativistic femtosecond electron bunches with an energy bandwidth in the order of 0.1%, as frequently used in ultrafast electron diffraction (UED) experiments for the investigation of ultrafast structural dynamics. The device operates in accumulation mode with 50 fs shot-to-shot timing jitter, and at a 30 keV electron energy, the full width at half maximum temporal resolution is 150 fs. Measured durations of pulses from our UED gun agree well with the predictions from the detailed charged particle trajectory simulations. PMID:21034115

Kassier, G H; Haupt, K; Erasmus, N; Rohwer, E G; von Bergmann, H M; Schwoerer, H; Coelho, S M M; Auret, F D

2010-10-01

347

Knots in Charged Polymers  

E-print Network

The interplay of topological constraints and Coulomb interactions in static and dynamic properties of charged polymers is investigated by numerical simulations and scaling arguments. In the absence of screening, the long-range interaction localizes irreducible topological constraints into tight molecular knots, while composite constraints are factored and separated. Even when the forces are screened, tight knots may survive as local (or even global) equilibria, as long as the overall rigidity of the polymer is dominated by the Coulomb interactions. As entanglements involving tight knots are not easy to eliminate, their presence greatly influences the relaxation times of the system. In particular, we find that tight knots in open polymers are removed by diffusion along the chain, rather than by opening up. The knot diffusion coefficient actually decreases with its charge density, and for highly charged polymers the knot's position appears frozen.

Paul G. Dommersnes; Yacov Kantor; Mehran Kardar

2002-07-10

348

Charge gradient microscopy  

PubMed Central

Here we present a simple and fast method to reliably image polarization charges using charge gradient microscopy (CGM). We collected the current from the grounded CGM probe while scanning a periodically poled lithium niobate single crystal and single-crystal LiTaO3 thin film on the Cr electrode. We observed current signals at the domains and domain walls originating from the displacement current and the relocation or removal of surface charges, which enabled us to visualize the ferroelectric domains at a scan frequency above 78 Hz over 10 ?m. We envision that CGM can be used in high-speed ferroelectric domain imaging and piezoelectric energy-harvesting devices. PMID:24760831

Hong, Seungbum; Tong, Sheng; Park, Woon Ik; Hiranaga, Yoshiomi; Cho, Yasuo; Roelofs, Andreas

2014-01-01

349

Charge gradient microscopy.  

PubMed

Here we present a simple and fast method to reliably image polarization charges using charge gradient microscopy (CGM). We collected the current from the grounded CGM probe while scanning a periodically poled lithium niobate single crystal and single-crystal LiTaO3 thin film on the Cr electrode. We observed current signals at the domains and domain walls originating from the displacement current and the relocation or removal of surface charges, which enabled us to visualize the ferroelectric domains at a scan frequency above 78 Hz over 10 ?m. We envision that CGM can be used in high-speed ferroelectric domain imaging and piezoelectric energy-harvesting devices. PMID:24760831

Hong, Seungbum; Tong, Sheng; Park, Woon Ik; Hiranaga, Yoshiomi; Cho, Yasuo; Roelofs, Andreas

2014-05-01

350

The long range properties of the compact U(1) lattice gauge theory with the multi-level algorithm  

E-print Network

The 4D compact U(1) lattice gauge theory (LGT) in the confinement phase is studied with the multi-level algorithm. The static potential, force and flux-tube profile between two static charges are precisely measured from correlation functions involving the Polyakov loop. Universality of the coefficient of the 1/r correction to the static potential, known as the Luescher term, and the transversal width of the flux-tube profile are investigated.

Koma, Y; Majumdar, P

2003-01-01

351

The long range properties of the compact U(1) lattice gauge theory with the multi-level algorithm  

Microsoft Academic Search

The 4D compact U(1) lattice gauge theory (LGT) in the confinement phase is studied with the multi-level algorithm. The static potential, force and flux-tube profile between two static charges are precisely measured from correlation functions involving the Polyakov loop. Universality of the coefficient of the 1r correction to the static potential, known as the Lüscher term, and the transversal width

Y. Koma; M. Koma; P. Majumdar

2004-01-01

352

An Exponential Compact Higher Order Scheme  

NASA Astrophysics Data System (ADS)

An exponential compact higher order scheme is developed for stationary convection-diffusion type of differential equations which inludes incompressible flow equations in stream function vorticity formulation. The scheme is, ingeneral, fourth order accurate however for one-dimensional constant convection and diffusion coefficients, the scheme is O(h6) and produces a tri-diagonal system of equations that can be solved efficiently using Thomas algorithm. For two-dimensional problems, the scheme produces an O(h4+k4) accuracy over a compact nine point stencil which can be solved using any line iterative approach with alternate direction implicit (ADI) procedure. The efficiency of the developed scheme is measured using wave number analysis. The analysis shows that the developed scheme has a much better spectral resolution than any of the existing higher order schemes.

Sanyasiraju, Y. V. S. S.; Mishra, Nachiketa

2009-09-01

353

Aegean: Compact source finding in radio images  

NASA Astrophysics Data System (ADS)

Aegean, written in python, finds compact sources within radio images by seeking out islands of pixels above a given threshold and then using the curvature of the image to determine how many Gaussian components should be used to describe the island. The Gaussian fitting is initiated with parameters determined from the curvature and intensity maps, and makes use of mpfit to perform a constrained fit. Aegean has been optimized for compact radio sources in images that have no diffuse background emission, but by pre-processing the images with a spatial filter, or by convolving an optical image with an appropriately small PSF, Aegean is able to produce excellent results in a range of applications.

Hancock, P. J.; Murphy, T.; Gaensler, B. M.; Hopkins, A.; Curran, J. R.

2012-12-01

354

Midwest reclamation methods combat soil compaction  

SciTech Connect

Soil compaction can be the root of reclamation evils, but various studies are working on solutions to solve the problem. A bucket-wheel excavator conveyor-spreader system, ripping, and other reclamation methods demonstrated during the 7th Midwest Reclamation Tour show promise in reclaiming land to farm and forest use. Held last September and sponsored by Southern Illinois University and the University of Kentucky, the tour surveyed mined lands in southern Illinois and western Kentucky. The tour demonstrated that soil compaction can be reduced with a conveyor-spreader system, subsoiling, soil reconstruction, and by using end-dumps and rippers. Row crop yields were substantially improved on plots where these methods were used. Reforestation methods, however, have shown less success and do not compare with the case or effectiveness of planting trees on ungraded spoil banks as was done before current reclamation laws were established.

Erhart, P.P.

1984-04-01

355

A compact PE memory for vision chips  

NASA Astrophysics Data System (ADS)

This paper presents a novel compact memory in the processing element (PE) for single-instruction multiple-data (SIMD) vision chips. The PE memory is constructed with 8 × 8 register cells, where one latch in the slave stage is shared by eight latches in the master stage. The memory supports simultaneous read and write on the same address in one clock cycle. Its compact area of 14.33 ?m2/bit promises a higher integration level of the processor. A prototype chip with a 64 × 64 PE array is fabricated in a UMC 0.18 ?m CMOS technology. Five types of the PE memory cell structure are designed and compared. The testing results demonstrate that the proposed PE memory architecture well satisfies the requirement of the vision chip in high-speed real-time vision applications, such as 1000 fps edge extraction.

Cong, Shi; Zhe, Chen; Jie, Yang; Nanjian, Wu; Zhihua, Wang

2014-09-01

356

A compact high field magnetic force microscope.  

PubMed

We present the design and performance of a simple and compact magnetic force microscope (MFM), whose tip-sample coarse approach is implemented by the piezoelectric tube scanner (PTS) itself. In brief, a square rod shaft is axially spring-clamped on the inner wall of a metal tube which is glued inside the free end of the PTS. The shaft can thus be driven by the PTS to realize image scan and inertial stepping coarse approach. To enhance the inertial force, each of the four outer electrodes of the PTS is driven by an independent port of the controller. The MFM scan head is so compact that it can easily fit into the 52mm low temperature bore of a 20T superconducting magnet. The performance of the MFM is demonstrated by imaging a manganite thin film at low temperature and in magnetic fields up to 15T. PMID:25189114

Zhou, Haibiao; Wang, Ze; Hou, Yubin; Lu, Qingyou

2014-12-01

357

Compact dusty clouds in cosmic environment  

NASA Astrophysics Data System (ADS)

We propose and discus a novel mechanism of the formation of compact dusty clouds in astrophysical environments. We show that the balance of forces operating in space dusty plasmas can cause the effect of dust self-confinement. As the result, cosmic dust can form stable spherical clouds (with typical sizes of the order of 10-100 AU or less and with total masses of the order of 10(-3) Earth mass or below), where the dust density can exceed the ambient level by many orders of magnitude. We predict that the formation of such clouds can occur in a broad range of plasma parameters, which indicates that this might be a fairly universal phenomenon operating in different astrophysical media. We argue that compact dusty clouds can be centers of rapid coagulations, and also operate as condensation seeds for a population of small-scale, cold, gaseous clumps in the diffuse interstellar medium.

Ivlev, Alexei; Tsytovich, Vadim; Burkert, Andreas

358

Compact Dusty Clouds in a Cosmic Environment  

NASA Astrophysics Data System (ADS)

A novel mechanism of the formation of compact dusty clouds in astrophysical environments is discussed. It is shown that the balance of collective forces operating in space dusty plasmas can result in the effect of dust self-confinement, generating equilibrium spherical clusters. The distribution of dust and plasma density inside such objects and their stability are investigated. Spherical dusty clouds can be formed in a broad range of plasma parameters, suggesting that this process of dust self-organization might be a generic phenomenon occurring in different astrophysical media. We argue that compact dusty clouds can represent condensation seeds for a population of small-scale, cold, gaseous clumps in the diffuse interstellar medium. They could play an important role in regulating its small-scale structure and its thermodynamical evolution.

Tsytovich, V. N.; Ivlev, A. V.; Burkert, A.; Morfill, G. E.

2014-01-01

359

RNA isolation and fractionation with compaction agents  

NASA Technical Reports Server (NTRS)

A new approach to the isolation of RNA from bacterial lysates employs selective precipitation by compaction agents, such as hexammine cobalt and spermidine. Using 3.5 mM hexammine cobalt, total RNA can be selectively precipitated from a cell lysate. At a concentration of 2 mM hexammine cobalt, rRNA can be fractionated from low molecular weight RNA. The resulting RNA mixture is readily resolved to pure 5S and mixed 16S/23S rRNA by nondenaturing anion-exchange chromatography. Using a second stage of precipitation at 8 mM hexammine cobalt, the low molecular weight RNA fraction can be isolated by precipitation. Compaction precipitation was also applied to the purification of an artificial stable RNA derived from Escherichia coli 5S rRNA and to the isolation of an Escherichia coli-expressed ribozyme. Copyright 2001 Academic Press.

Murphy, J. C.; Fox, G. E.; Willson, R. C.

2001-01-01

360

Charge and Carry  

NSDL National Science Digital Library

This site contains an activity on electrostatics. A styrofoam plate is rubbed with wool to give it a large electric charge that can be transferred to an aluminum pie pan. This electrophorus, or change carrier produces a spark that can be felt, seen, and heard. Materials needed, assembly, and an explanation of results are also provided. Also featured are directions to store up an even larger charge in a device called a Leyden jar, made from a plastic film can. This activity is part of Exploratorium's Science Snacks series.

2008-06-20

361

Charged vacuum bubble stability  

NASA Astrophysics Data System (ADS)

A type of scenario is considered where electrically charged vacuum bubbles, formed from degenerate or nearly degenerate vacua separated by a thin domain wall, are cosmologically produced due to the breaking of a discrete symmetry, with the bubble charge arising from fermions residing within the domain wall. Stability issues associated with wall tension, fermion gas, and Coulombic effects for such configurations are examined. The stability of a bubble depends upon parameters such as the symmetry breaking scale and the fermion coupling. A dominance of either the Fermi gas or the Coulomb contribution may be realized under certain conditions, depending upon parameter values.

Morris, J. R.

1999-01-01

362

Charges for linearized gravity  

E-print Network

Maxwell test fields as well as solutions of linearized gravity on the Kerr exterior admit non-radiating modes, i.e. non-trivial time-independent solutions. These are closely related to conserved charges. In this paper we discuss the non-radiating modes for linearized gravity, which may be seen to correspond to the Poincare Lie-algebra. The 2-dimensional isometry group of Kerr corresponds to a 2-parameter family of gauge-invariant non-radiating modes representing infinitesimal perturbations of mass and azimuthal angular momentum. We calculate the linearized mass charge in terms of linearized Newman-Penrose scalars.

Steffen Aksteiner; Lars Andersson

2013-01-12

363

Charged Lifshitz black holes  

NASA Astrophysics Data System (ADS)

We investigate modifications of the Lifshitz black hole solutions due to the presence of Maxwell charge in higher dimensions for arbitrary z and any topology. We find that the behavior of large black holes is insensitive to the topology of the solutions, whereas for small black holes significant differences emerge. We generalize a relation previously obtained for neutral Lifshitz black branes, and study more generally the thermodynamic relationship between energy, entropy, and chemical potential. We also consider the effect of Maxwell charge on the effective potential between objects in the dual theory.

Dehghani, M. H.; Mann, R. B.; Pourhasan, R.

2011-08-01

364

Compact hydrogen\\/helium isotope mass spectrometer  

Microsoft Academic Search

The compact hydrogen and helium isotope mass spectrometer of the present invention combines low mass-resolution ion mass spectrometry and beam-foil interaction technology to unambiguously detect and quantify deuterium (D), tritium (T), hydrogen molecule (H.sub.2, HD, D.sub.2, HT, DT, and T.sub.2), .sup.3 He, and .sup.4 He concentrations and concentration variations. The spectrometer provides real-time, high sensitivity, and high accuracy measurements. Currently,

Herbert O. Funsten; David J. McComas; Earl E. Scime

1996-01-01

365

Compact pulsed laser having improved heat conductance  

NASA Technical Reports Server (NTRS)

A highly efficient, compact pulsed laser having high energy to weight and volume ratios is provided. The laser utilizes a cavity reflector that operates as a heat sink and is essentially characterized by having a high heat conductivity, by being a good electrical insulator and by being substantially immune to the deleterious effects of ultra-violet radiation. Manual portability is accomplished by eliminating entirely any need for a conventional circulating fluid cooling system.

Yang, L. C. (inventor)

1977-01-01

366

Compact, Automated, Frequency-Agile Microspectrofluorimeter  

NASA Technical Reports Server (NTRS)

Compact, reliable, rugged, automated cell-culture and frequency-agile microspectrofluorimetric apparatus developed to perform experiments involving photometric imaging observations of single live cells. In original application, apparatus operates mostly unattended aboard spacecraft; potential terrestrial applications include automated or semiautomated diagnosis of pathological tissues in clinical laboratories, biomedical instrumentation, monitoring of biological process streams, and portable instrumentation for testing biological conditions in various environments. Offers obvious advantages over present laboratory instrumentation.

Fernandez, Salvador M.; Guignon, Ernest F.

1995-01-01

367

General relativistic compact stars with exotic matter  

SciTech Connect

We study the structures of general relativistic compact stars with exotic matter. Our study is based on axisymetric and stationary formalism including purely toroidal magnetic field. We also study the finite size effects of quark-hadron mixed phase on the structures of magnetars. For hybrid stars, we find the characteristic distribution of magnetic field, which has a discontinuity originated in the quark-hadron mixed phase. These distributions of magnetic field will change astrophysical phenomena, such as cooling processes.

Yasutake, N.; Kotake, K. [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Maruyama, T. [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Tatsumi, T. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Kiuchi, K. [Department of Physics, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan)

2009-05-04

368

The Compact Toroid Fueller - II Device  

Microsoft Academic Search

In our previous experiments with the first generation CTF device we were able to experimentally demonstrate compact toroid fuelling of TdeV (at B-toroidal of 1.4 T) without any adverse perturbation to the tokamak discharge [1]. These favorable results led to the fabrication of a second generation injector, CTF-II, for CT injection into a 2 T field. Initial operation of this

R. Raman; F. Martin; P. Gierszewski; G. Pacher; R. Decoste; D. Hwang; A. Hirose; H. McLean; C. Xiao

1996-01-01

369

Routing Table Compaction in Ternary CAM  

Microsoft Academic Search

k for each entry. Themask specifies which bits in the index areactive, thereby specifying the variable-lengthprefix. Table 1 is an example routing prefixtable stored in TCAM.Commercially available CAM costs muchmore than conventional memory, and TCAMis even more expensive. In addition, they consumemore power and dissipate more heat,posing a system design challenge. Therefore,it would be advantageous to compact the routingtable so

Huan Liu

2002-01-01

370

Light, Compact Pumper for Harbor Fires  

NASA Technical Reports Server (NTRS)

Report describes development of new transportable water-pumping unit for fire-fighting. Compact, self-contained unit provides fire protection at coastal and inland ports and is lighter than standard firetruck pumper of same capacity. Used to fight fires in harbors, cities, forests, refineries, chemical plants, and offshore drilling platforms. Other possible applications include cleaning up oilspills, pumping out ships, and flood control pumping.

Burns, R. A.

1983-01-01

371

Constructing Compact Models of Concurrent Java Programs  

Microsoft Academic Search

Finite-state verification technology (e.g., model checking) provides a powerful means to detect concurrency errors, which are often subtle and difficult to reproduce. Nevertheless, widespread use of this technology by developers is unlikely until tools provide automated support for extracting the required finite-state models directly from program source. In this paper, we explore the extraction of compact concurrency models from Java

James C. Corbett

1998-01-01

372

Compact 2-D graphical representation of DNA  

NASA Astrophysics Data System (ADS)

We present a novel 2-D graphical representation for DNA sequences which has an important advantage over the existing graphical representations of DNA in being very compact. It is based on: (1) use of binary labels for the four nucleic acid bases, and (2) use of the 'worm' curve as template on which binary codes are placed. The approach is illustrated on DNA sequences of the first exon of human ?-globin and gorilla ?-globin.

Randi?, Milan; Vra?ko, Marjan; Zupan, Jure; Novi?, Marjana

2003-05-01

373

Compact pulsed power generators for industrial applications  

Microsoft Academic Search

Summary form only given as follows. Compact pulsed power generators using high-power semiconductor switches are being developed at Nagaoka University of Technology, in collaboration with partners from Japanese industry. The switching units involved in these studies are the most up-to-date semiconductor switches such as static-induction thyristor (SI-thyristor), insulated gate bipolar transistor (IGBT), high-power metal-oxide-semiconductor field effect transistor (MOSFET), and semiconductor

W. Jiang; K. Yatsui; N. Shimizu; K. Iida; A. Tokuchi

2003-01-01

374

synthesis for a compact disc player  

Microsoft Academic Search

SUMMARY This paper considers the design and implementation of robust multivariable controllers for a compact disc mechanism.The design objective is to achieve good track-following and focusing performance in the presence of track disturbances, external mechanical shocks and structured norm-bounded plant uncertainty. This robust performance problem has been solved in the k-framework using the DK-iteration scheme. Limits of implementation necessitate the

Maarten Steinbuch; Pieter J. M. Van Groos; Gerrit Schootstra; Pepijn M. R. Wortelboer; Okko H. Bosgra

1998-01-01

375

Compact Disc Standards: An Introductory Overview  

Microsoft Academic Search

The success of the compact disc (CD) as a storage medium for digital audio has, over the last ten years, resulted in a number of initiatives to use the CD for other applications as well, e.g., as read-only memory for computers, as a storage medium for audio-visual material for multimedia applications, and as a storage medium for photographs. Each of

Jan H. M. Korst; Verus Pronk

1994-01-01

376

BOUNDARIES FOR BANACH SPACES DETERMINE WEAK COMPACTNESS  

E-print Network

of extremal points of the dual unit ball of a Banach space is a well-known example of a boundary. In 1980 if it is compact in the pointwise topology on the set of extremal points of the dual unit ball. Some years later(X) its unit sphere. The norm closed linear span of a subset A of X is written [A]. IN starts at 1. Our

Boyer, Edmond

377

Differentiation and compaction in the Skaergaard intrusion  

NASA Astrophysics Data System (ADS)

Although it is largely agreed that crystallization occurs inwardly in crystal mushes along the margins of magma chambers, the efficiency and mechanisms of differentiation are contended. The fractionation paradigm hinges on mass exchange between a crystal mush and the main magma reservoir resulting in coarse-grained, refractory (cumulate) rocks of primary crystals, and complementary enrichment of incompatible elements in the main magma. Diffusion, convection, liquid immiscibility and compaction have been proposed as mechanisms driving this mass exchange. We examine the efficiency of differentiation in basaltic crystal mushes of the Skaergaard magma chamber. The contents of incompatible elements such as phosphorus and calculated final porosities are smallest in cumulate rocks at the floor (~5% final porosity above the level of magnetite-in), intermediate at the walls (~20%) and highest at the roof (~55%). Mass exchange and differentiation are thus highly efficient at the floor but inefficient at the roof. This is best explained by compaction squeezing interstitial liquid out of the crystal mush preferentially at the floor. At the walls only mush with porosity less than ~20% was able to stick rather than collapsing into the chamber, resulting in moderately efficient differentiation. We conclude that compaction moderates the final crystal mush porosity and the efficiency of magma differentiation depending on chamber dynamics.

Tegner, C.; Thy, P.; Holness, M.; Jakobsen, J. K.; Salmonsen, L.; Humphreys, M.; Lesher, C. E.

2009-12-01

378

Compact high-speed scanning lidar system  

NASA Astrophysics Data System (ADS)

The compact High Speed Scanning Lidar (HSSL) was designed to meet the requirements for a rover GN&C sensor. The eye-safe HSSL's fast scanning speed, low volume and low power, make it the ideal choice for a variety of real-time and non-real-time applications including: 3D Mapping; Vehicle guidance and Navigation; Obstacle Detection; Orbiter Rendezvous; Spacecraft Landing / Hazard Avoidance. The HSSL comprises two main hardware units: Sensor Head and Control Unit. In a rover application, the Sensor Head mounts on the top of the rover while the Control Unit can be mounted on the rover deck or within its avionics bay. An Operator Computer is used to command the lidar and immediately display the acquired scan data. The innovative lidar design concept was a result of an extensive trade study conducted during the initial phase of an exploration rover program. The lidar utilizes an innovative scanner coupled with a compact fiber laser and high-speed timing electronics. Compared to existing compact lidar systems, distinguishing features of the HSSL include its high accuracy, high resolution, high refresh rate and large field of view. Other benefits of this design include the capability to quickly configure scan settings to fit various operational modes.

Dickinson, Cameron; Hussein, Marwan; Tripp, Jeff; Nimelman, Manny; Koujelev, Alexander

2012-06-01

379

Compact x-ray source and panel  

DOEpatents

A compact, self-contained x-ray source, and a compact x-ray source panel having a plurality of such x-ray sources arranged in a preferably broad-area pixelized array. Each x-ray source includes an electron source for producing an electron beam, an x-ray conversion target, and a multilayer insulator separating the electron source and the x-ray conversion target from each other. The multi-layer insulator preferably has a cylindrical configuration with a plurality of alternating insulator and conductor layers surrounding an acceleration channel leading from the electron source to the x-ray conversion target. A power source is connected to each x-ray source of the array to produce an accelerating gradient between the electron source and x-ray conversion target in any one or more of the x-ray sources independent of other x-ray sources in the array, so as to accelerate an electron beam towards the x-ray conversion target. The multilayer insulator enables relatively short separation distances between the electron source and the x-ray conversion target so that a thin panel is possible for compactness. This is due to the ability of the plurality of alternating insulator and conductor layers of the multilayer insulators to resist surface flashover when sufficiently high acceleration energies necessary for x-ray generation are supplied by the power source to the x-ray sources.

Sampayon, Stephen E. (Manteca, CA)

2008-02-12

380

Vibratory Shock Compaction of Granular Nuclear Waste  

NASA Astrophysics Data System (ADS)

Vibratory Shock Compaction (VSC) is a proven means for quickly forming strong, durable solids from a wide variety of granular materials[1]. Calcination of tank and other forms of high level radioactive wastes results in fine granular material that is quite amenable to volume reduction and stabilization. We have employed utilities coal ash as a calcine waste surrogate, blended with a quartz/feldspar-rich sand and 0-20% proportions of a borosilicate glass. The blends were compacted at room temperature and fired so that the glass melt could form an efficient binder. Included in the blend are small quantities of three RCRA metals, chromium, cadmium and lead, to permit testing for heavy metal stability. The VSC process is described and the results presented in terms of the waste form dissolution rates, compressive strengths, elastic moduli as determined from resonant frequency measurements, and heavy metal leach rates from Toxicity Characteristic Leaching Procedure measurements. Vibratory shock compaction employing glass binders appears to be a viable alternative to traditional vitrification processes for granular waste forms. [1] See http://www.resonantshockcompact.com

Amme, Robert C.

2004-05-01

381

Compact radio sources associated with molecular outflows  

NASA Astrophysics Data System (ADS)

The results of a search for radio emission associated with molecular outflows in regions with a compact object are reported. The data were collected with the VLA in 1981 and 1983 and covered 12 fields and 15 outflows. The frequencies used were 1.4 GHz, 5 GHz and 15 GHz aimed at S187, NGC 1333, L1551, NGC 2024, M78, NGC 2071, S255, CFK 961, S68, AS 353A, S106, and NGC 7129. The positions, flux densities, spectra and sizes of the compact radio sources scanned are provided for each region and discussed. Radio continuum emissions were recorded whenever the bolometric luminosity exceeded 100 solar luminosities, and from three sources with luminosities below that magnitude. The sources S106, CRL 961 and LkH-alpha 234 all had spectra and angular breadths typical of stars undergoing spherical mass outflow. Smooth surface brightness distributions for S254, S255 and S257 support an interpretation as uniform density spherical Stromgren spheres. High resolution radio maps of NGC 2071 and S255 reveal that both have three compact objects distributed as the objects in Trapezium. The NGC 2071 objects are confined to a space the size of the solar system, with electron densities greater than 10,000/cu cm.

Snell, R. L.; Bally, J.

1986-04-01

382

Compact Video Synopsis via Global Spatiotemporal Optimization.  

PubMed

Video synopsis aims at providing condensed representations of video datasets that can be easily captured from digital cameras nowadays, especially for daily surveillance videos. Previous work in video synopsis usually moves active objects along the time axis, which inevitably causes collisions among the moving objects if compressed much. In this paper, we propose a novel approach for compact video synopsis using a unified spatiotemporal optimization. Our approach globally shifts moving objects in both spatial and temporal domains, which shifting objects temporally to reduce the length of the video and shifting colliding objects spatially to avoid visible collision artifacts. Furthermore, using a multi-level patch relocation method, the moving space of the original video is expanded into a compact background based on environmental content to fit with the shifted objects. The shifted objects are finally composited with the expanded moving space to obtain the high-quality video synopsis, which is more condensed while remaining free of collision artifacts. Our experimental results have shown that the compact video synopsis we produced can be browsed quickly, preserves relative spatiotemporal relationships, and avoids motion collisions. PMID:22962088

Nie, Yongwei; Xiao, Chunxia; Sun, Hanqiu; Li, Ping

2012-08-22

383

Compact video synopsis via global spatiotemporal optimization.  

PubMed

Video synopsis aims at providing condensed representations of video data sets that can be easily captured from digital cameras nowadays, especially for daily surveillance videos. Previous work in video synopsis usually moves active objects along the time axis, which inevitably causes collisions among the moving objects if compressed much. In this paper, we propose a novel approach for compact video synopsis using a unified spatiotemporal optimization. Our approach globally shifts moving objects in both spatial and temporal domains, which shifting objects temporally to reduce the length of the video and shifting colliding objects spatially to avoid visible collision artifacts. Furthermore, using a multilevel patch relocation (MPR) method, the moving space of the original video is expanded into a compact background based on environmental content to fit with the shifted objects. The shifted objects are finally composited with the expanded moving space to obtain the high-quality video synopsis, which is more condensed while remaining free of collision artifacts. Our experimental results have shown that the compact video synopsis we produced can be browsed quickly, preserves relative spatiotemporal relationships, and avoids motion collisions. PMID:23929846

Nie, Yongwei; Xiao, Chunxia; Sun, Hanqiu; Li, Ping

2013-10-01

384

The Evolution of Compact Binary Star Systems  

NASA Astrophysics Data System (ADS)

We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Mergings of compact-star binaries are expected to be the most important sources for forthcoming gravitational-wave (GW) astronomy. In the first part of the review, we discuss observational manifestations of close binaries with NS and/or BH components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks, which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to the formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically-important thermonuclear SN Ia. We also consider AM CVn-stars, which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.

Postnov, Konstantin A.; Yungelson, Lev R.

2014-05-01

385

The Evolution of Compact Binary Star Systems  

E-print Network

We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Mergings of compact binary stars are expected to be the most important sources for the forthcoming gravitational-wave (GW) astronomy. In the first part of the review, we discuss observational manifestations of close binary stars with NS and/or black components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically important thermonuclear SN Ia. We also consider AM CVn-stars which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.

Konstantin Postnov; Lev Yungelson

2014-03-19

386

Compact multipolar representation of the electrostatic potential for flexible molecules  

NASA Astrophysics Data System (ADS)

A new method for generating a compact multipolar representation of the electrostatic potential (EP) for flexible molecules is presented. The method is based on a constrained minimization of the difference between the quantum mechanical and the classical EP. The fitting procedure used adopts the least absolute shrinkage and selection operator technique [R. Tibshirani, J. Roy. Stat. Soc. B 58, 267 (1996)] which can be seen as penalized ordinary least squares. The penalty function optimized for the particular molecule of interest effectively removes redundant multipoles. It is shown that the use of multiple conformations is crucial for the predictive ability of the EP model for flexible molecules. The multipole local coordinate systems are chosen in a way that best reflects the key conformational changes. It was demonstrated that such an approach improves the predictive ability of EP models. It also allows to exploit equivalence of atoms in the calculation of multipoles components. In the case of polar flexible molecules, the augmentation of the EP model based on charges by higher multipoles decreases the relative root mean square error by a factor of 1.5-5. The corresponding effect of enlargement of the set of multipoles was significantly reduced.

Chodkiewicz, Michal Leszek

2005-06-01

387

77 FR 22805 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact; Correction  

Federal Register 2010, 2011, 2012, 2013

The Federal Bureau of Investigation published a document in the Federal Register of April 3, 2012, concerning the date and location of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact). The document listed the wrong street...

2012-04-17

388

The size of compact extra dimensions from blackbody radiation laws  

NASA Astrophysics Data System (ADS)

In this work we generalize the Stefan-Boltzmann and Wien’s displacement laws for a D-dimensional manifold composed by 4 non-compact dimensions and D-4 compact dimensions, R×T. The electromagnetic field is assumed to pervade all compact and non-compact dimensions. In particular, the total radiated power becomes R(T)=?BT4+?D(a) TD, where a is the size of the compact extra dimensions. For D=10, predicted from String Theory, and D=11, from M-Theory, the outcomes agree with available experimental data for a as high as 2?10-7m.

Ramos, Ramaton; Boschi-Filho, Henrique

2014-01-01

389

What is the number of spiral galaxies in compact groups  

NASA Technical Reports Server (NTRS)

The distribution of morphological types of galaxies in compact groups is studied on plates from the 6 m telescope. In compact groups there are 57 percent galaxies of late morphological types (S + Irr), 23 percent lenticulars (SO) and 20 percent elliptical galaxies. The morphological content of compact groups is very nearly the same as in loose groups. There is no dependence of galaxy morphology on density in all compact groups (and possibly in loose groups). Genuine compact groups form only 60 percent of Hickson's list.

Tikhonov, N. A.

1990-01-01

390

Build a Charge Detector  

NSDL National Science Digital Library

In this hands-on activity, students explore the electrical force that takes place between two objects. Each student builds an electroscope and uses the device to draw conclusions about objects' charge intensity. Students also determine what factors influence electric force.

Integrated Teaching And Learning Program

391

Shaped charge jet particulation  

Microsoft Academic Search

An analytical model was developed to predict the breakup time of the jet from a shaped charge liner. The model is based on three presumptions. First, a kinematic expression for the breakup time; second, expression related to plastic stability; and finally, a material-based constitutive equation relating the stress, strain, strain rate, and temperature. In other words, the jet from a

William P. Walters; Richard L. Summers

1994-01-01

392

Spacecraft Charging Technology 1980.  

National Technical Information Service (NTIS)

The third Spacecraft Charging Technology Conference, sponsored by the National Aeronautics and Space Administration and the U.S. Air Force, was held at the Air Force Academy from November 12 to 14, 1980. The proceedings contain 66 papers, dealing with the...

N. J. Stevens, C. P. Pike

1981-01-01

393

Large-scale dynamic compaction of natural salt  

SciTech Connect

A large-scale dynamic compaction demonstration of natural salt was successfully completed. About 40 m{sup 3} of salt were compacted in three, 2-m lifts by dropping a 9,000-kg weight from a height of 15 m in a systematic pattern to achieve desired compaction energy. To enhance compaction, 1 wt% water was added to the relatively dry mine-run salt. The average compacted mass fractional density was 0.90 of natural intact salt, and in situ nitrogen permeabilities averaged 9X10{sup -14}m{sup 2}. This established viability of dynamic compacting for placing salt shaft seal components. The demonstration also provided compacted salt parameters needed for shaft seal system design and performance assessments of the Waste Isolation Pilot Plant.

Hansen, F.D.; Ahrens, E.H.

1996-05-01

394

Effects of Compaction and Temperature on Sorption and Diffusion of Cs and HTO in Compacted Bentonite Saturated with Saline Water  

SciTech Connect

The sorption and diffusion of Cs and tritiated water (HTO) in compacted bentonite was investigated at temperatures from 30 to 60 deg. C. The apparent (D{sub a}) and effective (D{sub e}) diffusion coefficients were determined by in-diffusion and through-diffusion experiments with a constant boundary concentration maintained. The temperature dependence of De and Da obeyed an Arrhenius-type equation, allowing determination of the activation energy for diffusion of Cs and HTO. The D{sub e} value of Cs was three times the D{sub e} of HTO, which is considered to be a result of surface-excess diffusion. Cs may be concentrated near the surface of the negatively charged clay, thus giving a large diffusive flux. The activation energies for Cs diffusion were 21.4{+-}2.8 kJ/mol and 37.3{+-}1.5 kJ/mol as determined based on D{sub e} and D{sub a}, respectively. This difference was due to the temperature dependence of the distribution coefficient K{sub d} of Cs. (authors)

Satoru Suzuki; Masashi Haginuma; Kazunori Suzuki [Nuclear Chemistry and Chemical Engineering Center, Institute of Research and Innovation, 1201 Takada, Kashiwa, 277-0861 (Japan)

2007-07-01

395

Use of a migration technique to study alteration of compacted sand-bentonite mixture in contact with concrete  

NASA Astrophysics Data System (ADS)

In this research, a migration technique was applied to accelerate the migration of calcium ions from the pore solution of concrete so as to investigate the alteration of compacted bentonite in contact with the concrete. A 15 V of direct current was used for a composite specimen with 100 mm in diameter and 100 mm in length in which the electrical potential gradient was equal to 167 V/m. This composite consists of compacted bentonite (Na-type) sand mixture and concrete that is adjacent to each other. After a target cumulative electric charge of 13 × 10 3 C was reached, the specimen was removed for analysis. The results of electron probe micro analyzer (EPMA) showed that the concentration of calcium became higher in the compacted bentonite in the vicinity of the interface with the concrete. This observation was supported by the results of thermogravimetry/differential thermal analysis (TG-DTA) that provided distinct evidences of reduced quantities of Ca(OH) 2 in the concrete in the vicinity of the interface with the compacted bentonite. Therefore, calcium ions migrated from the concrete to the compacted bentonite under the given electric field. The results of the X-ray diffraction (XRD) curves indicated possible transformation of the characteristic of the compacted bentonite. However depending on the mix proportions of concrete employed, altered characterization of the compacted bentonite was different. It was found that the swelling capacity of the compacted bentonite in contact with normal concrete was decreased to 64% of its initial swelling capacity as the ratio of calcium content to sodium content (Ca/Na) increased up to 3.7. On the other hand the swelling capacity of the compacted bentonite in contact with fly ash concrete was 85% of its initial swelling capacity with a ratio (Ca/Na) of 2.3. Accordingly the use of the electrical migration technique enables quantitative evaluation of the reduced swelling capacity of the compacted bentonite in accordance with different types of hardened concrete.

Sugiyama, Takafumi; Tsuji, Yukikazu

396

A compact radio frequency quadrupole for ion bunching in the WITCH experiment  

NASA Astrophysics Data System (ADS)

During the last several years the WITCH (Weak Interaction Trap for CHarged particles) experimental setup at ISOLDE has undergone various upgrades aiming at improvement of general performance. An essential innovation, a compact Radio Frequency Quadrupole (RFQ) ion cooler and buncher device, was designed and successfully commissioned as a part of the off-line tuning system of WITCH. The RFQ is coupled to the existing surface ionization ion source providing high intensity ion bunches (up to 107 ions per bunch) towards the pulsed drift tube and the Penning traps of WITCH. This achievement allows for loading and tuning of the Penning traps in the domain of space charge limits and grants off-line operation independently of the REX-ISOLDE ion source. The current upgrade allows for a more thorough and frequent testing with bunched stable ion beams of high intensities, which will be used for studying various systematic effects involved in experiments with radioactive ions.

Traykov, E.; Beck, M.; Breitenfeldt, M.; Delahaye, P.; De Leebeeck, V.; Friedag, P.; Herlert, A.; Geeraert, N.; Heirman, W.; Lønne, P.-I.; Mader, J.; Roccia, S.; Soti, G.; Tandecki, M.; Timmermans, M.; Thiboud, J.; Van Gorp, S.; Wauters, F.; Weinheimer, C.; Zákoucký, D.; Severijns, N.

2011-08-01

397

Disappearance of the negative charge in giant DNA with a folding transition.  

PubMed Central

In the present study we measure the electrophoretic mobility of giant T4 DNA (166 kbp) by electrophoretic light scattering for the elongated and folded compact states at different spermidine (trivalent cation) concentrations in 50 mM sodium maleate buffer (pH 6.0). It is found that the electrophoretic mobility of elongated DNA in the absence of the multivalent cation is seven times greater than that of fully folded compact DNA, where, with the increase of the concentration of spermidine, an abrupt transition is generated after a gradual decrease of the mobility. An analysis of the electrophoretic mobility suggests that the folded compact DNA chains almost completely lose their negative charges, by taking into account the difference of friction mechanism between an elongated and folded compact state. From the single chain observation by use of fluorescence microscopy, it is found that a phase-segregated structure is generated at intermediate concentrations of spermidine. The gradual decrease of the electrophoretic mobility in the transition region is, thus, attributed to the formation of the segregated state, exhibiting partial electroneutralization in the folded part. Disappearance of the negative charges in the completely folded compact DNAs is discussed in relation to the mechanism of transition, in terms of a first-order phase transition. PMID:11371456

Yamasaki, Y; Teramoto, Y; Yoshikawa, K

2001-01-01

398

Gated charged-particle trap  

DOEpatents

The design and operation of a new type of charged-particle trap provides simultaneous measurements of mass, charge, and velocity of large electrospray ions. The trap consists of a detector tube mounted between two sets of center-bored trapping plates. Voltages applied to the trapping plates define symmetrically-opposing potential valleys which guide axially-injected ions to cycle back and forth through the charge-detection tube. A low noise charge-sensitive amplifier, connected to the tube, reproduces the image charge of individual ions as they pass through the detector tube. Ion mass is calculated from measurement of ion charge and velocity following each passage through the detector.

Benner, W. Henry (Danville, CA)

1999-01-01

399

Development of a compact tomography camera system using a multianode photomultiplier tube for compact torus experiments  

SciTech Connect

A compact tomography camera system consisting of a photomultiplier tube, a multislit optical system, and a band-pass interference filter has been developed. The viewing area and spatial resolution can be configured by the arrangement of the slit system. The camera system has been specially designed for self-organized compact torus experiments having strong magnetohydrodynamics events with a submicrosecond time-scale. The developed system has been tested on a field-reversed configuration formed by the field-reversed theta-pinch. Performance evaluation of the system has been performed by comparison to the former optical system.

Tomuro, H.; Asai, T.; Iguchi, K.; Takahashi, Ts.; Hirano, Y. [Department of Physics, College of Science and Technology, Nihon University, Tokyo 101-8308 (Japan)

2010-10-15

400

Instrumentation for Studies of Electron Emission and Charging From Insulators  

NASA Technical Reports Server (NTRS)

Making measurements of electron emission properties of insulators is difficult since insulators can charge either negatively or positively under charge particle bombardment. In addition, high incident energies or high fluences can result in modification of a material s conductivity, bulk and surface charge profile, structural makeup through bond breaking and defect creation, and emission properties. We discuss here some of the charging difficulties associated with making insulator-yield measurements and review the methods used in previous studies of electron emission from insulators. We present work undertaken by our group to make consistent and accurate measurements of the electron/ion yield properties for numerous thin-film and thick insulator materials using innovative instrumentation and techniques. We also summarize some of the necessary instrumentation developed for this purpose including fast response, low-noise, high-sensitivity ammeters; signal isolation and interface to standard computer data acquisition apparatus using opto-isolation, sample-and-hold, and boxcar integration techniques; computer control, automation and timing using Labview software; a multiple sample carousel; a pulsed, compact, low-energy, charge neutralization electron flood gun; and pulsed visible and UV light neutralization sources. This work is supported through funding from the NASA Space Environments and Effects Program and the NASA Graduate Research Fellowship Program.

Thomson, C. D.; Zavyalov, V.; Dennison, J. R.

2004-01-01

401

An Ultra-Compact Marx-Type High-Voltage Generator  

SciTech Connect

This paper discusses the design of an ultra-compact, Marx-type, high-voltage generator. This system incorporates high-performance components that are closely coupled and integrated into an extremely compact assembly. Low profile, custom ceramic capacitors with coplanar extended electrodes provide primary energy storage. Low-inductance, spark-gap switches incorporate miniature gas cavities imbedded within the central region of the annular shaped capacitors, with very thin dielectric sections separating the energy storage capacitors. Carefully shaped electrodes and insulator surfaces are used throughout to minimize field enhancements, reduce fields at triple-point regions, and enable operation at stress levels closer to the intrinsic breakdown limits of the dielectric materials. Specially shaped resistors and inductors are used for charging and isolation during operation. Forward-coupling ceramic capacitors are connected across successive switch-capacitor-switch stages to assist in switching. Pressurized SF, gas is used for electrical insulation in the spark-gap switches and throughout the unit. The pressure housing is constructed entirely of dielectric materials, with segments that interlock with the low-profile switch bodies to provide an integrated support structure for all of the components. This ultra-compact Marx generator employs a modular design that can be sized as needed for a particular application. Units have been assembled with 4, 10, and 30 stages and operated at levels up to 100 kV per stage.

Goerz, D; Ferriera, T; Nelson, D; Speer, R; Wilson, M

2001-06-15

402

Hydraulic conductivity study of compacted clay soils used as landfill liners for an acidic waste.  

PubMed

Three natural clayey soils from Tunisia were studied to assess their suitability for use as a liner for an acid waste disposal site. An investigation of the effect of the mineral composition and mechanical compaction on the hydraulic conductivity and fluoride and phosphate removal of three different soils is presented. The hydraulic conductivity of these three natural soils are 8.5 × 10(-10), 2.08 × 10(-9) and 6.8 × 10(-10)m/s for soil-1, soil-2 and soil-3, respectively. Soil specimens were compacted under various compaction strains in order to obtain three wet densities (1850, 1950 and 2050 kg/m(3)). In this condition, the hydraulic conductivity (k) was reduced with increasing density of sample for all soils. The test results of hydraulic conductivity at long-term (>200 days) using acidic waste solution (pH=2.7, charged with fluoride and phosphate ions) shows a decrease in k with time only for natural soil-1 and soil-2. However, the specimens of soil-2 compressed to the two highest densities (1950 and 2050 kg/m(3)) are cracked after 60 and 20 days, respectively, of hydraulic conductivity testing. This damage is the result of a continued increase in the internal stress due to the swelling and to the effect of aggressive wastewater. The analysis of anions shows that the retention of fluoride is higher compared to phosphate and soil-1 has the highest sorption capacity. PMID:22980909

Hamdi, Noureddine; Srasra, Ezzeddine

2013-01-01

403

Physical Factors Affecting Plasmid DNA Compaction in Stearylamine-Containing Nanoemulsions Intended for Gene Delivery  

PubMed Central

Cationic lipids have been used in the development of non-viral gene delivery systems as lipoplexes. Stearylamine, a cationic lipid that presents a primary amine group when in solution, is able to compact genetic material by electrostatic interactions. In dispersed systems such as nanoemulsions this lipid anchors on the oil/water interface confering a positive charge to them. The aim of this work was to evaluate factors that influence DNA compaction in cationic nanoemulsions containing stearylamine. The influence of the stearylamine incorporation phase (water or oil), time of complexation, and different incubation temperatures were studied. The complexation rate was assessed by electrophoresis migration on agarose gel 0.7%, and nanoemulsion and lipoplex characterization was done by Dynamic Light Scattering (DLS). The results demonstrate that the best DNA compaction process occurs after 120 min of complexation, at low temperature (4 ± 1 °C), and after incorporation of the cationic lipid into the aqueous phase. Although the zeta potential of lipoplexes was lower than the results found for basic nanoemulsions, the granulometry did not change. Moreover, it was demonstrated that lipoplexes are suitable vehicles for gene delivery. PMID:24281666

Silva, Andre Leandro; Junior, Francisco Alexandrino; Verissimo, Lourena Mafra; Agnez-Lima, Lucymara Fassarella; Egito, Lucila Carmem Monte; de Oliveira, Anselmo Gomes; do Egito, Eryvaldo Socrates Tabosa

2012-01-01

404

Physical factors affecting plasmid DNA compaction in stearylamine-containing nanoemulsions intended for gene delivery.  

PubMed

Cationic lipids have been used in the development of non-viral gene delivery systems as lipoplexes. Stearylamine, a cationic lipid that presents a primary amine group when in solution, is able to compact genetic material by electrostatic interactions. In dispersed systems such as nanoemulsions this lipid anchors on the oil/water interface confering a positive charge to them. The aim of this work was to evaluate factors that influence DNA compaction in cationic nanoemulsions containing stearylamine. The influence of the stearylamine incorporation phase (water or oil), time of complexation, and different incubation temperatures were studied. The complexation rate was assessed by electrophoresis migration on agarose gel 0.7%, and nanoemulsion and lipoplex characterization was done by Dynamic Light Scattering (DLS). The results demonstrate that the best DNA compaction process occurs after 120 min of complexation, at low temperature (4 ± 1 °C), and after incorporation of the cationic lipid into the aqueous phase. Although the zeta potential of lipoplexes was lower than the results found for basic nanoemulsions, the granulometry did not change. Moreover, it was demonstrated that lipoplexes are suitable vehicles for gene delivery. PMID:24281666

Silva, André Leandro; Alexandrino, Francisco; Verissimo, Lourena Mafra; Agnez-Lima, Lucymara Fassarella; Egito, Lucila Carmem Monte; de Oliveira, Anselmo Gomes; do Egito, Eryvaldo Socrates Tabosa

2012-01-01

405

Note: compact helical pulse forming line for the generation of longer duration rectangular pulse.  

PubMed

The helical pulsed forming line (PFL) can generate longer duration rectangular pulse in a smaller length. A compact PFL using helical water line is designed and experimentally investigated. The impedance of the helical PFL is 22 [ohm sign]. The compactness is achieved in terms of reduction in length of the PFL by a factor of 5.5 using helical water PFL as compared to coaxial water PFL of same length. The helical PFL was pulsed charged to 200 kV using a high voltage pulse transformer in 4.5 ?s and discharged into the matched 22 ? resistive load through a self-breakdown pressurized spark gap switch. The rectangular voltage pulse of 100 kV, 260 ns (FWHM) is measured across the load. The effect of reduction in water temperature on the pulse width is also studied experimentally. The increase in pulse width up to 7% more is observed by reducing the temperature of the deionized water to 5 °C. It will further reduce the length of the PFL and make the system small for compact pulsed power drivers. PMID:22755669

Sharma, Surender Kumar; Deb, P; Sharma, Archana; Shukla, R; Prabaharan, T; Adhikary, B; Shyam, A

2012-06-01

406

Advanced Construction of Compact Containment BWR  

SciTech Connect

The reactor concept considered in this paper has a mid/small power output, a compact containment and a simplified BWR configuration with comprehensive safety features. Compact Containment BWR (CCR) is being developed with matured BWR technologies together with innovative systems/components, will provide attractiveness for the energy market in the world due to its flexibility in energy demands as well as in site conditions, its high potential in reducing investment risk and its safety feature facilitating public acceptance. The flexibility is achieved by CCR's mid/small power output of 400 MWe class and capability of long operating cycle (refueling intervals). The high investment potential is expected from CCR's simplification/innovation in design such as natural circulation core cooling with the bottom located short core, top mounted upper entry control rod drives (CRDs) with ring-type dryers and simplified safety system with high pressure resistible primary containment vessel (PCV) concept. The natural circulation core eliminates recirculation pumps as well as needs for maintenance of such pumps. The top mounted upper entry CRDs enable the bottom located short core in RPV. The safety feature mainly consists of large water inventory above the core without large penetration below the top of the core, passive cooling system by isolation condenser (IC), high pressure resistible PCV and in-vessel retention (IVR) capability. The large inventory increases the system response time in case of design base accidents including loss of coolant accidents. The IC suppresses PCV pressure by steam condensation without any AC power. Cooling the molten core inside the RPV if the core should be damaged by loss of core coolability could attain the IVR. CCR's specific self-standing steel high pressure resistible PCV is designed to contain minimum piping and valves inside with reactor pressure vessel (RPV), only 13 m in diameter and 24 m in height. This compact PCV makes it possible to fabricate and perform pressure-test at the factory and transport to the construction-site as a module. Basing on CCR design concept of simplification and compact, reactor building layout design has been carried out. Layout design has been performed taking into account module construction, reduced system and components and compact PCV. As a result, CCR's reactor building, specific volume to power output value is almost equal to ABWR one. Module fabrication and construction method is promising technology from the points of construction duration shortening and construction cost reduction. Electrical equipment are piled up to multi-layer and connected and tested at the factory and transported to the construction-site in one module. Other equipment rooms and areas are also built into the various pre-fabricated module types in CCR construction. The construction of the CCR by the large module is planned to achieve only 24-month construction period from bedrock inspection to commercial operation. The CCR has possibilities of attaining both economical and safe small reactor by simplified system and compact PCV technologies with advanced construction. (authors)

Takahashi, M.; Maruyama, T.; Mori, H.; Hoshino, K.; Hijioka, Y.; Heki, H.; Nakamaru, M. [Toshiba Corporation (Japan); Hoshi, T. [Japan Atomic Power Company (Japan)

2006-07-01

407

Transverse-structure electrostatic charged particle beam lens  

DOEpatents

Electrostatic particle-beam lenses using a concentric co-planar array of independently biased rings can be advantageous for some applications. Traditional electrostatic lenses often consist of axial series of biased rings, apertures, or tubes. The science of lens design has devoted much attention to finding axial arrangements that compensate for the substantial optical aberrations of the individual elements. Thus, as with multi-element lenses for light, a multi-element charged-particle lens can have optical behavior that is far superior to that of the individual elements. Transverse multiple-concentric-ring lenses achieve high performance, while also having advantages in terms of compactness and optical versatility.

Moran, Michael J. (Pleasanton, CA)

1998-01-01

408

Transverse-structure electrostatic charged particle beam lens  

DOEpatents

Electrostatic particle-beam lenses using a concentric co-planar array of independently biased rings can be advantageous for some applications. Traditional electrostatic lenses often consist of axial series of biased rings, apertures, or tubes. The science of lens design has devoted much attention to finding axial arrangements that compensate for the substantial optical aberrations of the individual elements. Thus, as with multi-element lenses for light, a multi-element charged-particle lens can have optical behavior that is far superior to that of the individual elements. Transverse multiple-concentric-ring lenses achieve high performance, while also having advantages in terms of compactness and optical versatility. 7 figs.

Moran, M.J.

1998-10-13

409

Raytheon's next generation compact inline cryocooler architecture  

NASA Astrophysics Data System (ADS)

Infrared sensors face a multitude of cryocooler integration challenges such as exported disturbance, efficiency, scalability, maturity, and cost. As a result, cryocooler selection has become application dependent, oftentimes requiring extensive trade studies to determine the most suitable architecture. To optimally meet the needs of next generation passive infrared (IR) sensors, the Compact Inline Raytheon Single Stage Pulse Tube (CI-RP1) and Compact Inline Raytheon Hybrid Stirling/Pulse Tube 2-Stage (CI-RSP2) cryocoolers are being developed to satisfy this suite of requirements. This lightweight, compact, efficient, low vibration cryocooler combines proven 1-stage and 2-stage cold-head architectures with an inventive set of warm-end mechanisms into a single mechanical module, allowing the moving mechanisms for the compressor and the Stirling displacer to be consolidated onto a common axis and in a common working volume. The CI cryocooler is a significant departure from the current Stirling cryocoolers in which the compressor mechanisms are remote from the Stirling displacer mechanism. Placing all of the mechanisms in a single volume and on a single axis provides benefits in terms of package size (30% reduction), mass (30% reduction), thermodynamic efficiency (<20% improvement) and exported vibration performance (<=25 mN peak in all three orthogonal axes at frequencies from 1 to 500 Hz). The main benefit of axial symmetry is that proven balancing techniques and hardware can be utilized to null all motion along the common axis. Low vibration translates to better sensor performance resulting in simpler, more direct mechanical mounting configurations, eliminating the need for convoluted, expensive, massive, long lead damping hardware.

Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T.

2013-09-01

410

Are compact groups hostile towards faint galaxies?  

NASA Astrophysics Data System (ADS)

Aims: The goal of this work is to understand whether the extreme environment of compact groups (CGs) can affect the distribution and abundance of faint galaxies around them. Methods: We performed an analysis of the faint galaxy population in the vicinity of compact and normal groups. We built a light-cone mock galaxy catalogue constructed from the Millennium Run Simulation II plus a semi-analytical model of galaxy formation. We identified a sample of CGs in the mock catalogue as well as a control sample of normal galaxy groups and computed the projected number density profiles of faint galaxies around the first and the second ranked galaxies. We also compared the profiles obtained from the semi-analytical galaxies in CGs with those obtained from observational data. In addition, we investigated whether the ranking or the luminosity of a galaxy is the most important parameter in the determination of the centre around which the clustering of faint galaxies occurs. Results: There is no particular influence of the extreme compact group (CG) environment on the number of faint galaxies in such groups compared to control groups. When selecting normal groups with separations between the first and second ranked galaxies similar to what is observed in CGs, the faint galaxy projected number density profiles in CGs and normal groups are similar in shape and height. We observed a similar behaviour of the population of faint galaxies in observations and simulations in the regions closer to the first and second ranked galaxies. Finally, we find that the projected density of faint galaxies is higher around luminous galaxies, regardless of the ranking in the CG. Conclusions: The semi-analytical approach shows that CGs and their surroundings do not represent a hostile enough environment to make faint galaxies behave differently than in normal groups. Appendix A is available in electronic form at http://www.aanda.org

Zandivarez, Ariel; Díaz-Giménez, Eugenia; Mendes de Oliveira, Claudia; Gubolin, Henrique

2014-12-01

411

Gauss' Law - Point Charge  

NSDL National Science Digital Library

This EJS (Easy Java Simulation) based simulation allows the user to investigate the effects of changing the radius of a Gaussian surface and of changing the charge of a point charge on the flux and electric field along the Gaussian surface. Users may run the simulations by downloading the jar file. A lesson plan and a student study guide are available at the mirror web site. This resource is part of Project ITOP (Improving the Teaching of Physics), a graduate program offered at University of Massachusetts-Boston. The archived computer models are hosted and maintained as part of the BU Physics Simulation collection. The materials in this collection were created with Easy Java Simulations (EJS), a modeling tool that allows users to easily generate modify and share computer models and simulations.

Sweeney, Renee

2011-01-27

412

Compact quantum dots for single-molecule imaging.  

PubMed

Single-molecule imaging is an important tool for understanding the mechanisms of biomolecular function and for visualizing the spatial and temporal heterogeneity of molecular behaviors that underlie cellular biology (1-4). To image an individual molecule of interest, it is typically conjugated to a fluorescent tag (dye, protein, bead, or quantum dot) and observed with epifluorescence or total internal reflection fluorescence (TIRF) microscopy. While dyes and fluorescent proteins have been the mainstay of fluorescence imaging for decades, their fluorescence is unstable under high photon fluxes necessary to observe individual molecules, yielding only a few seconds of observation before complete loss of signal. Latex beads and dye-labeled beads provide improved signal stability but at the expense of drastically larger hydrodynamic size, which can deleteriously alter the diffusion and behavior of the molecule under study. Quantum dots (QDs) offer a balance between these two problematic regimes. These nanoparticles are composed of semiconductor materials and can be engineered with a hydrodynamically compact size with exceptional resistance to photodegradation (5). Thus in recent years QDs have been instrumental in enabling long-term observation of complex macromolecular behavior on the single molecule level. However these particles have still been found to exhibit impaired diffusion in crowded molecular environments such as the cellular cytoplasm and the neuronal synaptic cleft, where their sizes are still too large (4,6,7). Recently we have engineered the cores and surface coatings of QDs for minimized hydrodynamic size, while balancing offsets to colloidal stability, photostability, brightness, and nonspecific binding that have hindered the utility of compact QDs in the past (8,9). The goal of this article is to demonstrate the synthesis, modification, and characterization of these optimized nanocrystals, composed of an alloyed HgxCd1-xSe core coated with an insulating CdyZn1-yS shell, further coated with a multidentate polymer ligand modified with short polyethylene glycol (PEG) chains (Figure 1). Compared with conventional CdSe nanocrystals, HgxCd1-xSe alloys offer greater quantum yields of fluorescence, fluorescence at red and near-infrared wavelengths for enhanced signal-to-noise in cells, and excitation at non-cytotoxic visible wavelengths. Multidentate polymer coatings bind to the nanocrystal surface in a closed and flat conformation to minimize hydrodynamic size, and PEG neutralizes the surface charge to minimize nonspecific binding to cells and biomolecules. The end result is a brightly fluorescent nanocrystal with emission between 550-800 nm and a total hydrodynamic size near 12 nm. This is in the same size range as many soluble globular proteins in cells, and substantially smaller than conventional PEGylated QDs (25-35 nm). PMID:23093375

Smith, Andrew M; Nie, Shuming

2012-01-01

413

Compact Plasma Accelerator for Micropropulsion Applications  

NASA Technical Reports Server (NTRS)

There is a need for a low power, light-weight (compact), high specific impulse electric propulsion device to satisfy mission requirements for microsatellite (1 to 20 kg) class missions. Satisfying these requirements entails addressing the general problem of generating a sufficiently dense plasma within a relatively small volume and then accelerating it. In the work presented here, the feasibility of utilizing a magnetic cusp to generate a dense plasma over small length scales of order 1 mm is investigated. This approach could potentially mitigate scaling issues associated with conventional ion thruster plasma containment schemes. Plume and discharge characteristics were documented using a Faraday probe and a retarding potential analyzer.

Foster, John E.

2001-01-01

414

The Dugdale model for compact specimen  

NASA Technical Reports Server (NTRS)

Plastic zone size and crack tip opening displacement (CTOD) equations were developed. Boundary collocation analyses were used to analyze the compact specimen subjected to various loading conditions (pin loads, concentrated forces, and uniform pressure acting on the crack surface). Stress intensity factor and crack surface displacement equations for some of these loadings were developed and used to obtain the Dugdale model. The results from the equations for plastic zone size and CTOD agreed well with numerical values calculated by Terada for crack length to width ratios greater than 0.4.

Mall, S.; Newman, J. C., Jr.

1985-01-01

415

The Dugdale model for the compact specimen  

NASA Technical Reports Server (NTRS)

Plastic zone size and crack tip opening displacement (CTOD) equations were developed. Boundary collocation analyses were used to analyze the compact specimen subjected to various loading conditions (pin loads, concentrated forces, and uniform pressure acting on the crack surface). Stress intensity factor and crack surface displacement equations for some of these loadings were developed and used to obtain the Dugdale model. The results from the equations for plastic zone size and CTOD agreed well with numerical values calculated by Terada for crack length to width ratios greater than 0.4.

Mall, S.; Newman, J. C., Jr.

1983-01-01

416

Compact Toffoli gate using weighted graph states  

E-print Network

We introduce three compact graph states that can be used to perform a measurement-based Toffoli gate. Given a weighted graph of six, seven or eight qubits, we show that success probabilities of 1/4, 1/2 and 1 respectively can be achieved. Our study puts a measurement-based version of this important quantum logic gate within the reach of current experiments. As the graphs are setup-independent, they could be realized in a variety of systems, including linear optics and ion-traps.

M. S. Tame; S. K. Ozdemir; M. Koashi; N. Imoto; M. S. Kim

2008-09-09

417

Compact Toffoli gate using weighted graph states  

E-print Network

We introduce three compact graph states that can be used to perform a measurement-based Toffoli gate. Given a weighted graph of six, seven or eight qubits, we show that success probabilities of 1/4, 1/2 and 1 respectively can be achieved. Our study puts a measurement-based version of this important quantum logic gate within the reach of current experiments. As the graphs are setup-independent, they could be realized in a variety of systems, including linear optics and ion-traps.

Tame, M S; Koashi, M; Imoto, N; Kim, M S

2008-01-01

418

Strange matter in rotating compact stars  

E-print Network

We have constructed equations of state involving various exotic forms of matter with large strangeness fraction such as hyperon matter, Bose-Einstein condensates of antikaons and strange quark matter. First order phase transitions from hadronic to antikaon condensed and quark matter are considered here. The hadronic phase is described by the relativistic field theoretical model. Later those equations of state are exploited to investigate models of uniformly rotating compact stars. The effect of rotation on the third family branch for the equation of state involving only antikaon condensates is investigated. We also discuss the back bending phenomenon due to a first order phase transition from $K^-$ condensed to quark matter.

Sarmistha Banik; Matthias Hanauske; Debades Bandyopadhyay

2004-12-29

419

The Kepler equation for inspiralling compact binaries  

E-print Network

Compact binaries consisting of neutron stars / black holes on eccentric orbit undergo a perturbed Keplerian motion. The perturbations are either of relativistic origin or are related to the spin, mass quadrupole and magnetic dipole moments of the binary components. The post-Newtonian motion of such systems decouples into radial and angular parts. We present here for the first time the radial motion of such a binary encoded in a generalized Kepler equation, with the inclusion of all above-mentioned contributions, up to linear order in the perturbations. Together with suitably introduced parametrizations, the radial motion is solved completely.

Zoltán Keresztes; Balázs Mikóczi; László Á. Gergely

2005-10-20

420

Nonlinearly stable compact schemes for shock calculations  

NASA Technical Reports Server (NTRS)

The applications of high-order, compact finite difference methods in shock calculations are discussed. The main concern is to define a local mean which will serve as a reference for introducing a local nonlinear limiting to control spurious numerical oscillations while maintaining the formal accuracy of the scheme. For scalar conservation laws, the resulting schemes can be proven total-variation stable in one space dimension and maximum-norm stable in multiple space dimensions. Numerical examples are shown to verify accuracy and stability of such schemes for problems containing shocks. These ideas can also be applied to other implicit schemes such as the continuous Galerkin finite element methods.

Cockburn, Bernardo; Shu, Chi-Wang

1992-01-01

421

Eccentric Motion of Spinning Compact Binaries  

E-print Network

The equations of motion for spinning compact binaries on eccentric orbits are treated perturbatively in powers of a fractional mass-difference ordering parameter. The solution is valid through first order in the mass-difference parameter. A canonical point transformation removes the leading order terms of the spin-orbit Hamiltonian which induce a wiggling precession of the orbital angular momentum around the conserved total angular momentum, a precession which disappears in the case of equal masses or one single spin. Action-angle variables are applied which make a canonical perturbation theory easily treatable.

Tessmer, Manuel

2014-01-01

422

Eccentric Motion of Spinning Compact Binaries  

E-print Network

The equations of motion for spinning compact binaries on eccentric orbits are treated perturbatively in powers of a fractional mass-difference ordering parameter. The solution is valid through first order in the mass-difference parameter. A canonical point transformation removes the leading order terms of the spin-orbit Hamiltonian which induce a wiggling precession of the orbital angular momentum around the conserved total angular momentum, a precession which disappears in the case of equal masses or one single spin. Action-angle variables are applied which make a canonical perturbation theory easily treatable.

Manuel Tessmer; Gerhard Schäfer

2014-06-02

423

Colliding black holes and pulsating compact objects  

NASA Astrophysics Data System (ADS)

This thesis presents a study of two kinds of sources of gravitational waves: black hole collisions and pulsating compact objects (either a black hole or a star) The computational solution of the Einstein field equations for the coalescence of two black holes is of great interest for both theoretical and astrophysical reasons. Despite the strong motivation for results, outstanding mathematical and numerical problems have prevented a complete analysis of two black hole systems. Workers in the field have resorted to approximate techniques that make the study of such systems tractable. In Chapter 2 we use the close limit approximation to compute the gravitational energy radiated, and the recoil velocity acquired, by a system of two unequal mass black holes colliding head-on. A recent independent comparison of our approximate result with a full numerical analysis of the problem shows excellent agreement. Until recently, vibrations even of relativistically compact stars were studied using Newtonian physics and the weak field limit of general relativity. The study of the problem in the framework of general relativity revealed the existence of modes of vibration (w modes) characteristic of the spacetime geometry and therefore modes not predicted by Newtonian physics. Chapter 3 addresses the question of whether these modes can be excited in a natural astrophysical process. A small particle with a given energy and angular momentum is scattered by a compact star or black hole and in the process excites, although weakly, the w modes. Chapter 4 compares the study of pulsating stars in a Newtonian framework and in a fully relativistic setting. To excite the vibrations of the stellar model we use time dependent surface mass density and surface stress in a thin spherical shell surrounding the star. Even for stars as compact as typical neutron stars (radius ~ 5G/ c2 × mass), the two theories predict essentially the same level of excitation of the f (fluid) modes of the star. The w modes are not excited for these stars. All of the chapters in this thesis, except the introductory chapter, have been published or have been submitted for publication.

Andrade, Zeferino

2000-08-01

424

Strange matter in rotating compact stars  

NASA Astrophysics Data System (ADS)

We have constructed equations of state involving various exotic forms of matter with large strangeness fraction such as hyperon matter, Bose-Einstein condensates of antikaons and strange quark matter. First-order phase transitions from hadronic to antikaon condensed and quark matter are considered here. The hadronic phase is described by the relativistic field theoretical model. Later those equations of state are exploited to investigate models of uniformly rotating compact stars. The effect of rotation on the third family branch for the equation of state involving only antikaon condensates is investigated. We also discuss the back bending phenomenon due to a first-order phase transition from K- condensed to quark matter.

Banik, Sarmistha; Hanauske, Matthias; Bandyopadhyay, Debades

2005-06-01

425

Compact proton spectrometers for measurements of shock  

SciTech Connect

The compact Wedge Range Filter (WRF) proton spectrometer was developed for OMEGA and transferred to the National Ignition Facility (NIF) as a National Ignition Campaign (NIC) diagnostic. The WRF measures the spectrum of protons from D-{sup 3}He reactions in tuning-campaign implosions containing D and {sup 3}He gas; in this work we report on the first proton spectroscopy measurement on the NIF using WRFs. The energy downshift of the 14.7-MeV proton is directly related to the total {rho}R through the plasma stopping power. Additionally, the shock proton yield is measured, which is a metric of the final merged shock strength.

Mackinnon, A; Zylstra, A; Frenje, J A; Seguin, F H; Rosenberg, M J; Rinderknecht, H G; Johnson, M G; Casey, D T; Sinenian, N; Manuel, M; Waugh, C J; Sio, H W; Li, C K; Petrasso, R D; Friedrich, S; Knittel, K; Bionta, R; McKernan, M; Callahan, D; Collins, G; Dewald, E; Doeppner, T; Edwards, M J; Glenzer, S H; Hicks, D; Landen, O L; London, R; Meezan, N B

2012-05-02

426

Winds from disks in compact binaries  

SciTech Connect

We herein present an observational and theoretical review of the winds of compact binaries. After a brief consideration of the accretion disk coronae and winds of X-ray binaries, the review concentrates on the winds of cataclysmic variables (CVs). Specifically, we consider the related problems of the geometry and mass-loss rate of the winds of CVs, their ionization state and variability, and the results from studies of eclipsing CVs. Finally, the properties of bona fide accretion disk wind models are reviewed.

Mauche, C.W.

1993-10-27

427

Compact Stellar Systems around NGC 1399  

Microsoft Academic Search

We have obtained spectroscopic redshifts of colour-selected point sources in\\u000afour wide area VLT-FLAMES fields around the Fornax Cluster giant elliptical\\u000agalaxy NGC 1399, identifying as cluster members 30 previously unknown faint\\u000a(-10.5compact stellar systems (CSS), and improving redshift\\u000aaccuracy for 23 previously catalogued CSS.\\u000a By amalgamating our results with CSS from previous 2dF observations and\\u000aexcluding CSS dynamically

P. Firth; M. J. Drinkwater; E. A. Evstigneeva; M. D. Gregg; A. M. Karick; J. B. Jones; S. Phillipps

2007-01-01

428

Dynamic Hysteresis in Compacted Magnetic Nanoparticles  

NASA Astrophysics Data System (ADS)

The frequency and temperature dependent magnetic response of a bulk soft magnetic nanocomposite made by compacting Fe10Co 90 nanoparticles was measured and modeled. Electron microscopy and x-ray diffraction were used to characterize the size, composition, and structure of the nanoparticles and nanocomposite. Polyol synthesis was used to produce 200 nm particles with average grain size 20 nm and large superparamagnetic fraction. The nanoparticles were consolidated to 90% theoretical density by plasma pressure compaction. The compacted nanoparticles retained the 20 nm average grain size and large superparamagnetic fraction. The nanocomposite resistivity was more than three times that of the bulk alloy. Vibrating sample and SQUID-MPMS magnetometers were used for low frequency magnetic measurements of the nanoparticles and nanocomposite. Compaction reduced the coercivity from 175 Oe to 8 Oe and the effective anisotropy from 124 x 10 3 ergs/cc to 7.9 x 103 ergs/cc. These reductions were caused by increased exchange coupling between surface nanograins, consistent with predictions from the Random Anisotropy model. Varying degrees of exchange coupling existed within the nanocomposite, contributing to a distribution of energy barriers. A permeameter was used for frequency dependent magnetic measurements on a toroid cut from the nanocomposite. Complex permeability, coercivity, and power loss were extracted from dynamic minor hysteresis loops measured over a range of temperatures (77 K - 873 K) and frequencies (0.1 kHz - 100 kHz). The real and imaginary parts of the complex permeability spectrum showed asymmetries consistent with a distribution of energy barriers and high damping. When the complex permeability, power loss, and coercivity were scaled relative to the peak frequency of the imaginary permeability, all fell on universal curves. Various microscopic and macroscopic models for the complex permeability were investigated. The complex permeability was successfully fit by modifying the Cole-Davidson model with a scaling factor that extended the model to higher damping. The additional damping was consistent with the damping from eddy current modeling, showing that the nanocomposite's complex permeability could be explained by combining microscopic effects (the distribution of energy barriers represented by the Cole-Davidson model) with macroscopic effects (damping due to eddy currents).

Chowdary, Krishna M.

429

The origin of ultra-compact binaries  

NASA Technical Reports Server (NTRS)

The origin of ultra-compact binaries composed of a neutron star and a low-mass (about 0.06 solar mass) white dwarf is considered. Taking account of the systemic losses of mass and angular momentum, it was found that a serious difficulty exists in the scenarios which involve tidal captures of a normal star (a main sequence star or a red giant) by a neutron star. This difficulty can be avoided if a red giant star is captured by a massive white dwarf (M is approx. greater than 1.2 solar masses), which becomes a neutron star through the accretion induced collapse.

Hachisu, Izumi; Miyaji, Shigeki; Saio, Hideyuki

1987-01-01

430

Compact solitons, bags, and radial excitations  

SciTech Connect

Compact nodal soliton solutions for a Dirac equation with fractional nonlinearity are studied. This model is a natural field-theoretical generalization of the MIT bag model. In the limit where the power nonlinearity is arbitrarily small, the exact nodal solutions are obtained and shown to be different from the corresponding radial excitations in the MIT bag model. The complete energy spectrum is also different, except for massless confined fields in 1+1 dimensions. Finally the nonexistence of spherical solitons with negative parity is established.

Mathieu, P.

1985-12-15

431

Flexible Momentum Compaction Return Arcs for RLAs  

SciTech Connect

Neutrino Factories and Muon Colliders require rapid acceleration of short-lived muons to multi-GeV and TeV energies. A Recirculating Linear Accelerator (RLA) that uses a single Linac and teardrop return arcs can provide exceptionally fast and economical acceleration to the extent that the focusing range of the RLA quadrupoles allows each muon to pass several times through each high-gradient cavity and the cost of the return arcs is appropriate. Flexible Momentum Compaction (FMC) lattice designs for the teardrop return arcs provide sufficient momentum acceptance to allow multiple passes of each sign of muon in one string of magnets to improve cost-effectiveness.

Trbojevic, Dejan; Bogacz, Alex; Bogacz, Slawomir; Bogacz, Alex; Bogacz, Slawomir; Johnson, Rolland; Popovic, Milorad

2008-07-01

432

Outflows and shocks in compact radio sources  

E-print Network

We report some key results from the optical emission line study of a complete sample of compact radio sources. We find strong evidence for jet-driven outflows in the circum-nuclear emission line gas namely: 1) highly broadened and blueshifted emission line components (up to 2000 km/s), 2) shock ionised gas (broader, shifted components), 3) consistency in the scales of the emission line gas and the radio source and 4) trends between the maximum outflow velocity and radio source size (and orientation). Full details can be found in Holt (2005).

J. Holt; C. N. Tadhunter; R. Morganti

2005-09-06

433

Automated Charge Capture  

Microsoft Academic Search

The primary motivation, or return on investment (ROI), for purchasing an EMR for most office-based physician practices focuses\\u000a predominately on the ability to enhance and automate charge capture. In the paper world, a patient would be seen by a physician,\\u000a who would create notes on paper records. The physician would then typically complete a “superbill”—a fairly standardized form\\u000a that contains

Christopher Reeves; Jerry Stonemetz

434

Battery charge condition monitoring  

Microsoft Academic Search

Basic techniques are presented for determining the charge condition of electric-vehicle propulsion batteries of both the lead--acid and nickel--cadmium types. The techniques presented include those employing measurement of battery parameters, such as electrolyte properties, voltage, and internal resistance, and those utilizing coulometric measurements. An application example employing the coulometric approach is described to demonstrate the usefulness of an accurate battery

Christianson

1974-01-01

435

Sewerage service charges  

E-print Network

by taxation; whereas, those yielding special benefits to certain individuals or pro? perties should be supported by charges levied against the individuals or properties so benefited. There can be no question that the entire community benefits from... they attempt to show that the furnishing of sewerage service to residents of a city is a governmental function and the cost of construction and/or operation of such a system should be borne by general taxation. Do not such municipal enterprises as water...

Wright, Samuel Robert

2013-10-04

436

A compact high-voltage pulse generator based on pulse transformer with closed magnetic core.  

PubMed

A compact high-voltage nanosecond pulse generator, based on a pulse transformer with a closed magnetic core, is presented in this paper. The pulse generator consists of a miniaturized pulse transformer, a curled parallel strip pulse forming line (PFL), a spark gap, and a matched load. The innovative design is characterized by the compact structure of the transformer and the curled strip PFL. A new structure of transformer windings was designed to keep good insulation and decrease distributed capacitance between turns of windings. A three-copper-strip structure was adopted to avoid asymmetric coupling of the curled strip PFL. When the 31 microF primary capacitor is charged to 2 kV, the pulse transformer can charge the PFL to 165 kV, and the 3.5 ohm matched load can deliver a high-voltage pulse with a duration of 9 ns, amplitude of 84 kV, and rise time of 5.1 ns. When the load is changed to 50 ohms, the output peak voltage of the generator can be 165 kV, the full width at half maximum is 68 ns, and the rise time is 6.5 ns. PMID:20370165

Zhang, Yu; Liu, Jinliang; Cheng, Xinbing; Bai, Guoqiang; Zhang, Hongbo; Feng, Jiahuai; Liang, Bo

2010-03-01

437

Charge detection in semiconductor nanostructures  

E-print Network

In this thesis nanometer scale charge sensors are used to study charge transport in two solid state systems: Lateral GaAs quantum dots and hydrogenated amorphous silicon (a-Si:H). In both of these experiments we use ...

MacLean, Kenneth (Kenneth MacLean, III)

2010-01-01

438

THE ELECTRIC PROGRAM INVESTMENT CHARGE  

E-print Network

THE ELECTRIC PROGRAM INVESTMENT CHARGE: PROPOSED 201214 TRIENNIAL INVESTMENT PLAN The California Energy Commission has prepared this triennial investment plan (2012 ­ 2014) for the new Electric, 2012, Phase 2 Decision 1205037. This decision established the Electric Program Investment Charge

439

Prerequisites for chiral charge order  

NASA Astrophysics Data System (ADS)

The chiral charge density wave state which was recently discovered in TiSe2 can be understood as a combination of orbital and charge order. Here, we discuss the prerequisite material properties for this type of chiral charge order to emerge. We find that although both the lattice and orbital structure constrain the set of candidate materials, there remains a class of materials in which chiral charge order is expected to emerge.

van Wezel, Jasper

2012-06-01

440

Modular Battery Charge Controller  

NASA Technical Reports Server (NTRS)

A new approach to masterless, distributed, digital-charge control for batteries requiring charge control has been developed and implemented. This approach is required in battery chemistries that need cell-level charge control for safety and is characterized by the use of one controller per cell, resulting in redundant sensors for critical components, such as voltage, temperature, and current. The charge controllers in a given battery interact in a masterless fashion for the purpose of cell balancing, charge control, and state-of-charge estimation. This makes the battery system invariably fault-tolerant. The solution to the single-fault failure, due to the use of a single charge controller (CC), was solved by implementing one CC per cell and linking them via an isolated communication bus [e.g., controller area network (CAN)] in a masterless fashion so that the failure of one or more CCs will not impact the remaining functional CCs. Each micro-controller-based CC digitizes the cell voltage (V(sub cell)), two cell temperatures, and the voltage across the switch (V); the latter variable is used in conjunction with V(sub cell) to estimate the bypass current for a given bypass resistor. Furthermore, CC1 digitizes the battery current (I1) and battery voltage (V(sub batt) and CC5 digitizes a second battery current (I2). As a result, redundant readings are taken for temperature, battery current, and battery voltage through the summation of the individual cell voltages given that each CC knows the voltage of the other cells. For the purpose of cell balancing, each CC periodically and independently transmits its cell voltage and stores the received cell voltage of the other cells in an array. The position in the array depends on the identifier (ID) of the transmitting CC. After eight cell voltage receptions, the array is checked to see if one or more cells did not transmit. If one or more transmissions are missing, the missing cell(s) is (are) eliminated from cell-balancing calculations. The cell-balancing algorithm is based on the error between the cell s voltage and the other cells and is categorized into four zones of operation. The algorithm is executed every second and, if cell balancing is activated, the error variable is set to a negative low value. The largest error between the cell and the other cells is found and the zone of operation determined. If the error is zero or negative, then the cell is at the lowest voltage and no balancing action is needed. If the error is less than a predetermined negative value, a Cell Bad Flag is set. If the error is positive, then cell balancing is needed, but a hysteretic zone is added to prevent the bypass circuit from triggering repeatedly near zero error. This approach keeps the cells within a predetermined voltage range.

Button, Robert; Gonzalez, Marcelo

2009-01-01

441

Compact Stirling cooling of astronomical detectors  

E-print Network

MAIA, a three-channel imager targeting fast cadence photometry, was recently installed on the Mercator telescope (La Palma, Spain). This instrument observes a 9.4 x 14.1 arcmin field of view simultaneously in three color bands ($u$, $g$ and $r$), using three of the largest (un-) available frame-transfer CCDs, namely the 2k x 6k CCD42-C0 from e2v. As these detectors are housed in three separate cryostats, compact cooling devices are required that offer sufficient power to cool the large chips to a temperature of 165K. We explored a broad spectrum of cooling options and technologies to cool the MAIA detectors. Finally, compact free-piston Stirling coolers were selected, namely the CryoTel MT cryo-coolers from SUNPOWER, that can extract 5W of heat at a temperature of 77K. In this contribution we give details of the MAIA detector cooling solution. We also discuss the general usability of this type of closed-cycle cryo-coolers for astronomical detectors. They offer distinct advantages but the vibrations caused by ...

Raskin, Gert; Pessemier, Wim; Padilla, Jesus Perez; Vandersteen, Jeroen

2013-01-01

442

Plasma transport in a compact ignition tokamak  

SciTech Connect

Nominal predicted plasma conditions in a compact ignition tokamak are illustrated by transport simulations using experimentally calibrated plasma transport models. The range of uncertainty in these predictions is explored by using various models which have given almost equally good fits to experimental data. Using a transport model which best fits the data, thermonuclear ignition occurs in a Compact Ignition Tokamak design with major radius 1.32 m, plasma half-width 0.43 m, elongation 2.0, and toroidal field and plasma current ramped in six seconds from 1.7 to 10.4 T and 0.7 to 10 MA, respectively. Ignition is facilitated by 20 MW of heating deposited off the magnetic axis near the /sup 3/He minority cyclotron resonance layer. Under these conditions, sawtooth oscillations are small and have little impact on ignition. Tritium inventory is minimized by preconditioning most discharges with deuterium. Tritium is injected, in large frozen pellets, only after minority resonance preheating. Variations of the transport model, impurity influx, heating profile, and pellet ablation rates, have a large effect on ignition and on the maximum beta that can be achieved.

Singer, C.E.; Ku, L.P; Bateman, G.

1987-02-01

443

Results of Compact Stellarator Engineering Trade Studies  

SciTech Connect

number of technical requirements and performance criteria can drive stellarator costs, e.g., tight tolerances, accurate coil positioning, low aspect ratio (compactness), choice of assembly strategy, metrology, and complexity of the stellarator coil geometry. With the completion of a seven-year design and construction effort of the National Compact Stellarator Experiment (NCSX) it is useful to interject the NCSX experience along with the collective experiences of the NCSX stellarator community to improving the stellarator configuration. Can improvements in maintenance be achieved by altering the stellarator magnet configuration with changes in the coil shape or with the combination of trim coils? Can a mechanical configuration be identified that incorporates a partial set of shaped fixed stellarator coils along with some removable coil set to enhance the overall machine maintenance? Are there other approaches that will simplify the concepts, improve access for maintenance, reduce overall cost and improve the reliability of a stellarator based power plant? Using ARIES-CS and NCSX as reference cases, alternative approaches have been studied and developed to show how these modifications would favorably impact the stellarator power plant and experimental projects. The current status of the alternate stellarator configurations being developed will be described and a comparison made to the recently designed and partially built NCSX device and the ARIES-CS reactor design study.

Tom Brown, L. Bromberg, M. Cole

2009-05-27

444

Quantum Circuit Simplification and Level Compaction  

E-print Network

Quantum circuits are time dependent diagrams describing the process of quantum computation. Every (quantum) algorithm must be mapped into a quantum circuit to be able to run it on a quantum hardware. Optimal synthesis of quantum circuits is intractable and heuristic methods must be employed, resulting in non-optimal circuit specifications. In this paper, we consider the use of local optimization technique called the templates to simplify and compact levels in a quantum circuit initially found by other means. We present and analyze templates in the general case, and then provide particular details for the circuits composed of NOT, CNOT and controlled-sqrt-of-NOT gates. We introduce templates for this set of gates and apply them to simplify and compact levels in quantum simulations of multiple control Toffoli gates and quantum Boolean circuits found by other authors. While the number of templates and runtime of our software are quite small, the reduction in number of quantum gates and number of levels is often ...

Maslov, D L; Miller, D M

2006-01-01

445

Compact Offner-Wynne imaging spectrometers  

NASA Astrophysics Data System (ADS)

Some ideas that were developed by Wynne to improve the performance of the Offner unit magnification imaging system are used to design Offner imaging spectrometers to which a concentric meniscus lens has been added. The new degrees of freedom associated to the meniscus lens allow removing image aberrations far from the paraxial region in a wide annular area or even more, in two concentric annular areas. This provides a great flexibility of design as it is shown below in four examples. In these examples, the slit length, the f-number or the spectral resolution has been optimized while retaining almost diffraction-limited spot size, with rather separate slit and image, and getting quite compact designs in comparison to the original Offner system. In particular, the most compact system (~50×40×30 mm3) has an f-number of 1.86, a slit length of 9.6 mm and covers a spectral range from 400 to 1000 nm, being diffraction-limited for wavelengths longer than 450 nm.

Prieto-Blanco, Xesús; de la Fuente, Raúl

2014-10-01

446

Spontaneously quenched ?-ray spectra from compact sources  

NASA Astrophysics Data System (ADS)

Aims: We have studied a mechanism for producing intrinsic broken power-law ?-ray spectra in compact sources. This is based on the principles of automatic photon quenching, according to which ?-rays are being absorbed on spontaneously produced soft photons whenever the injected luminosity in ?-rays lies above a certain critical value. Methods: We derived an analytical expression for the critical ?-ray compactness in the case of power-law injection. For the case where automatic photon quenching is relevant, we calculated analytically the emergent steady-state ?-ray spectra. We also performed numerical calculations in order to back up our analytical results. Results: We show that a spontaneously quenched power-law ?-ray spectrum obtains a photon index 3?/2, where ? is the photon index of the power-law at injection. Thus, large spectral breaks of the ?-ray photon spectrum, e.g. ?? ? 1, can be obtained by this mechanism. We also discuss additional features of this mechanism that can be tested observationally. Finally, we fit the multiwavelength spectrum of a newly discovered blazar (PKS 0447-439) by using such parameters to explain the break in the ?-ray spectrum by means of spontaneous photon quenching, under the assumption that its redshift lies in the range 0.1 < z < 0.24.

Petropoulou, M.; Arfani, D.; Mastichiadis, A.

2013-09-01

447

Compact modeling of STT-MTJ devices  

NASA Astrophysics Data System (ADS)

STT-MTJ is a promising device for future high-density and low-power integrated systems. To enable design exploration of STT-MTJ, this paper presents a fully compact model for efficient SPICE simulation. Derived from the fundamental LLG equation, the new model consists of RC elements that are compact equations of device geometry and material properties. They support transient SPICE simulations, providing necessary details beyond the macromodel and enable resilient memory design. The accuracy of the model is validated with numerical results and published data. Scaling analysis shows the sensitivity of STT-MTJ to its geometry. We also did variability analysis with Monte Carlo simulation of the basic 1T1MTJ memory cell to study the bit error rate performance for different transistor size and programming current profile. We show that there is a tradeoff between programming energy and cell area for the same bit error rate constraint. Finally we derive the cell size that achieves minimum energy consumption for a given bit error rate constraint (primary) and latency or area constraint (secondary).

Xu, Zihan; Yang, Chengen; Mao, Manqing; Sutaria, Ketul B.; Chakrabarti, Chaitali; Cao, Yu

2014-12-01

448

Pyroflow Compact: The next generation CFB boiler  

SciTech Connect

CFB technology is the modern way to burn coal and other solid fuels. This technology was specifically developed to address today`s needs for fuel flexibility and low emissions. The low furnace temperatures characteristic of CFB technology provide for (a) low NO{sub x} emissions, (b) low SO{sub 2} emissions via simple furnace limestone injection and (c) the ability to fire a wide range of fuels because slagging is avoided. Lack of pulverizers and stack gas scrubbers results in a simple design with low maintenance costs and high availability. Ahlstrom, responsible for many innovations in CFB technology, has recently developed an improved CFB boiler design called the Pyroflow Compact. This new design retains all the benefits of the proven AHLSTROM PYROFLOW{reg_sign}CFB boiler while providing many advantages. This paper will describe the design features of the new Pyroflow Compact design, the advantages of this new design, operating experience, an up-to-date list of projects and Ahlstrom`s future plans for the new design.

Darling, S.L. [Pyropower Corp., San Diego, CA (United States)

1995-12-31

449

Compaction wave profiles in granular HMX  

SciTech Connect

Meso-scale simulations of a compaction wave in a granular bed of HMX have been performed. The grains are fully resolved in order that the change in porosity across the wave front is determined by the elastic-plastic response of the grains rather than an empirical law for the porosity as a function of pressure. Numerical wave profiles of the pressure and velocity are compared with data from a gas gun experiment. The experiment used an initial porosity of 36%, and the wave had a pressure comparable to the yield strength of the grains. The profiles are measured at the front and back of the granular bed. The transit time for the wave to travel between the gauges together with the Hugoniot jump conditions determines the porosity behind the wave front. In the simulations the porosity is determined by the yield strength and stress concentrations at the contact between grains. The value of the yield strength needed to match the experiment is discussed. Analysis of the impedance match of the wave at the back gauge indicates that the compaction wave triggers a small amount of burn, less than 1% mass fraction, on the micro-second time scale of the experiment.

Menikoff, Ralph

2001-01-01

450

Compaction Wave Profiles in Granular HMX  

NASA Astrophysics Data System (ADS)

Meso-scale simulations of a compaction wave in a granular bed of HMX have been performed. The grains are fully resolved in order that the change in porosity across the wave front is determined by the elastic-plastic response of the grains rather than an empirical law for the porosity as a function of pressure. Numerical wave profiles of the pressure and velocity are compared with data from a gas gun experiment. The experiment used an initial porosity of 36%, and the wave had a pressure comparable to the yield strength of the grains. The profiles are measured at the front and back of the granular bed. The transit time for the wave to travel between the gauges together with the Hugoniot jump conditions determines the porosity behind the wave front. In the simulations the porosity is determined by the yield strength and stress concentrations at the contact between grains. The value of the yield strength needed to match the experiment is discussed. Analysis of the impedance match of the wave at the back gauge indicates that the compaction wave triggers a small amount of burn, less than 1 % mass fraction, on the micro-second time scale of the experiment.

Menikoff, Ralph

2002-07-01

451

Compaction Wave Profiles in Granular HMX  

NASA Astrophysics Data System (ADS)

Meso-scale simulations of a compaction wave in a granular bed of HMX have been performed. The grains are fully resolved in order that the change in porosity across the wave front is determined by the elastic-plastic response of the grains rather than an empirical law for the porosity as a function of pressure. Numerical wave profiles of the pressure and velocity are compared with data from a gas gun experiment. The experiment used an initial porosity of 36%, and the wave had a pressure comparable to the yield strength of the grains. The profiles are measured at the front and back of the granular bed. The transit time for the wave to travel between the gauges together with the Hugoniot jump conditions determines the porosity behind the wave front. In the simulations the porosity is determined by the yield strength and stress concentration at the contact between grains. The value of the yield strength needed to match the experiment is discussed. Analysis of the impedance match of the wave at the back gauge indicates that the compaction wave triggers a small amount of burn, less than 1% mass fraction, on the micro-second time scale of the experiment.

Menikoff, Ralph

2001-06-01

452

Results of Compact Stellarator Eengineering Trade Studies  

SciTech Connect

A number of technical requirements and performance criteria can drive stellarator costs, e.g., tight tolerances, accurate coil positioning, low aspect ratio (compactness), choice of assembly strategy, metrology, and complexity of the stellarator coil geometry. With the completion of a seven-year design and construction effort of the National Compact Stellarator Experiment (NCSX) it is useful to interject the NCSX experience along with the collective experiences of the NCSX stellarator community to improving the stellarator configuration. Can improvements in maintenance be achieved by altering the stellarator magnet configuration with changes in the coil shape or with the combination of trim coils? Can a mechanical configuration be identified that incorporates a partial set of shaped fixed stellarator coils along with some removable coil set to enhance the overall machine maintenance? Are there other approaches that will simplify the concepts, improve access for maintenance, reduce overall cost and improve the reliability of a stellarator based power plant? Using ARIES-CS and NCSX as reference cases, alternative approaches have been studied and developed to show how these modifications would favorably impact the stellarator power plant and experimental projects. The current status of the alternate stellarator configurations being developed will be described and a comparison made to the recently designed and partially built NCSX device and the ARIES-CS reactor design study.

T. Brown, L. Bromberg, and M. Cole

2009-09-25

453

ROSAT Observations of Compact Groups of Galaxies  

E-print Network

A search for X-ray emission from compact groups revealed detection from 8 out of the 12 HCG images extracted from the ROSAT public archive. For two of them the X-ray emission originates from galaxies in the group. On the contrary, three groups show an extended emission clearly caused by hot intracluster gas. A Raymond-Smith hot plasma model provides an excellent fit to the X-ray spectra. The estimated temperatures are distributed in a quite narrow range (from 0.73 to 0.92 keV) and are consistent, within the errors, with 0.9 keV. The luminosity ranging from 0.75 to $5.1\\cdot10^{42}$erg s$^{-1}$. The most relevant result is the low metal abundance surely detected in two of them and likely in a third that characterizes the hot gas cloud responsible for the X-ray emission. The data concerning the remaining 3 detected compact groups are not sufficient to discriminate with certainty between diffuse and/or point-like X-ray emission. However the results of the spectral analysis point to the presence of a hot gas again with low metal abundance.

P. Saracco; P. Ciliegi

1994-12-11

454

Compact wavefunctions from compressed imaginary time evolution  

E-print Network

Simulation of quantum systems promises to deliver physical and chemical predictions for the frontiers of technology. Unfortunately, the exact representation of these systems is plagued by the exponential growth of dimension with the number of particles, or colloquially, the curse of dimensionality. The success of approximation methods has hinged on the relative simplicity of physical systems with respect to the exponentially complex worst case. Exploiting this relative simplicity has required detailed knowledge of the physical system under study. In this work, we introduce a general and efficient black box method for many-body quantum systems that utilizes technology from compressed sensing to find the most compact wavefunction possible without detailed knowledge of the system. It is a Multicomponent Adaptive Greedy Iterative Compression (MAGIC) scheme. No knowledge is assumed in the structure of the problem other than correct particle statistics. This method can be applied to many quantum systems such as spins, qubits, oscillators, or electronic systems. As an application, we use this technique to compute ground state electronic wavefunctions of hydrogen fluoride and recover 98% of the basis set correlation energy or equivalently 99.996% of the total energy with $50$ configurations out of a possible $10^7$. Building from this compactness, we introduce the idea of nuclear union configuration interaction for improving the description of reaction coordinates and use it to study the dissociation of hydrogen fluoride and the helium dimer.

Jarrod R. McClean; Alán Aspuru-Guzik

2014-09-25

455

A compact holographic optical tweezers instrument  

NASA Astrophysics Data System (ADS)

Holographic optical tweezers have found many applications including the construction of complex micron-scale 3D structures and the control of tools and probes for position, force, and viscosity measurement. We have developed a compact, stable, holographic optical tweezers instrument which can be easily transported and is compatible with a wide range of microscopy techniques, making it a valuable tool for collaborative research. The instrument measures approximately 30×30×35 cm and is designed around a custom inverted microscope, incorporating a fibre laser operating at 1070 nm. We designed the control software to be easily accessible for the non-specialist, and have further improved its ease of use with a multi-touch iPad interface. A high-speed camera allows multiple trapped objects to be tracked simultaneously. We demonstrate that the compact instrument is stable to 0.5 nm for a 10 s measurement time by plotting the Allan variance of the measured position of a trapped 2 ?m silica bead. We also present a range of objects that have been successfully manipulated.

Gibson, G. M.; Bowman, R. W.; Linnenberger, A.; Dienerowitz, M.; Phillips, D. B.; Carberry, D. M.; Miles, M. J.; Padgett, M. J.

2012-11-01

456

Charging Users for Library Service.  

ERIC Educational Resources Information Center

Examines the question of instituting direct charges for library service, using on-line bibliographic searching as an example, and contrasts this with the current indirect charging system where services are paid for by taxes. Information, as a merit good, should be supplied with or without direct charges, depending upon user status. (CWM)

Cooper, Michael D.

1978-01-01

457

A Stable Massive Charged Particle  

E-print Network

We consider the possibility of the existence of a stable massive charged particle by a minimal extension of the standard model particle content. Absolute stability in the case of singly charged particle is not possible if the usual doublet Higgs exists, unless a discrete symmetry is imposed.But a doubly charged particle is absolutely stable.

G. Rajasekaran

2011-05-26

458

PhyzGuide: Electrostatic Charge  

NSDL National Science Digital Library

This article contains some of the history of how electromagnetic theory was developed, along with some very general principles of what we know about static charges. This includes a brief description of types of charges and their properties, what classifies as a conductor or insulator, and how charge is measured.

Baird, Dean

2006-11-18

459

Holography, charge and baryon asymmetry  

E-print Network

The reason for baryon asymmetry in our universe has been a pertinent question for many years. The holographic principle suggests a charged preon model underlies the Standard Model of particle physics and any such charged preon model requires baryon asymmetry. This note estimates the baryon asymmetry predicted by charged preon models in closed inflationary Friedmann universes.

T. R. Mongan

2009-11-18

460

DNA methylation effects on tetra-nucleosome compaction and aggregation.  

PubMed

DNA CpG methylation has been associated with chromatin compaction and gene silencing. Whether DNA methylation directly contributes to chromatin compaction remains an open question. In this study, we used fluorescence fluctuation spectroscopy (FFS) to evaluate the compaction and aggregation of tetra-nucleosomes containing specific CpG patterns and methylation levels. The compactness of both unmethylated and methylated tetra-nucleosomes is dependent on DNA sequences. Specifically, methylation of the CpG sites located in the central dyad and the major grooves of DNA seem to have opposite effects on modulating the compactness of tetra-nucleosomes. The interactions among tetra-nucleosomes, however, seem to be enhanced because of DNA methylation independent of sequence contexts. Our finding can shed light on understanding the role of DNA methylation in determining nucleosome positioning pattern and chromatin compactness. PMID:25296315

Jimenez-Useche, Isabel; Nurse, Nathan P; Tian, Yuqing; Kansara, Bhargav S; Shim, Daphne; Yuan, Chongli

2014-10-01

461

Chromatin compaction protects genomic DNA from radiation damage.  

PubMed

Genomic DNA is organized three-dimensionally in the nucleus, and is thought to form compact chromatin domains. Although chromatin compaction is known to be essential for mitosis, whether it confers other advantages, particularly in interphase cells, remains unknown. Here, we report that chromatin compaction protects genomic DNA from radiation damage. Using a newly developed solid-phase system, we found that the frequency of double-strand breaks (DSBs) in compact chromatin after ionizing irradiation was 5-50-fold lower than in decondensed chromatin. Since radical scavengers inhibited DSB induction in decondensed chromatin, condensed chromatin had a lower level of reactive radical generation after ionizing irradiation. We also found that chromatin compaction protects DNA from attack by chemical agents. Our findings suggest that genomic DNA compaction plays an important role in maintaining genomic integrity. PMID:24130727

Takata, Hideaki; Hanafusa, Tomo; Mori, Toshiaki; Shimura, Mari; Iida, Yutaka; Ishikawa, Kenichi; Yoshikawa, Kenichi; Yoshikawa, Yuko; Maeshima, Kazuhiro

2013-01-01

462