Simulation of Cold Flow in a Truncated Ideal Nozzle with Film Cooling

NASA Technical Reports Server (NTRS)

Braman, K. E.; Ruf, J. H.

2015-01-01

Flow transients during rocket start-up and shut-down can lead to significant side loads on rocket nozzles. The capability to estimate these side loads computationally can streamline the nozzle design process. Towards this goal, the flow in a truncated ideal contour (TIC) nozzle has been simulated using RANS and URANS for a range of nozzle pressure ratios (NPRs) aimed to match a series of cold flow experiments performed at the NASA MSFC Nozzle Test Facility. These simulations were performed with varying turbulence model choices and for four approximations of the supersonic film injection geometry, each of which was created with a different simplification of the test article geometry. The results show that although a reasonable match to experiment can be obtained with varying levels of geometric fidelity, the modeling choices made do not fully represent the physics of flow separation in a TIC nozzle with film cooling.

Biot-Savart helicity versus physical helicity: A topological description of ideal flows

NASA Astrophysics Data System (ADS)

Sahihi, Taliya; Eshraghi, Homayoon

2014-08-01

For an isentropic (thus compressible) flow, fluid trajectories are considered as orbits of a family of one parameter, smooth, orientation-preserving, and nonsingular diffeomorphisms on a compact and smooth-boundary domain in the Euclidian 3-space which necessarily preserve a finite measure, later interpreted as the fluid mass. Under such diffeomorphisms the Biot-Savart helicity of the pushforward of a divergence-free and tangent to the boundary vector field is proved to be conserved and since these circumstances present an isentropic flow, the conservation of the "Biot-Savart helicity" is established for such flows. On the other hand, the well known helicity conservation in ideal flows which here we call it "physical helicity" is found to be an independent constant with respect to the Biot-Savart helicity. The difference between these two helicities reflects some topological features of the domain as well as the velocity and vorticity fields which is discussed and is shown for simply connected domains the two helicities coincide. The energy variation of the vorticity field is shown to be formally the same as for the incompressible flow obtained before. For fluid domains consisting of several disjoint solid tori, at each time, the harmonic knot subspace of smooth vector fields on the fluid domain is found to have two independent base sets with a special type of orthogonality between these two bases by which a topological description of the vortex and velocity fields depending on the helicity difference is achieved since this difference is shown to depend only on the harmonic knot parts of velocity, vorticity, and its Biot-Savart vector field. For an ideal magnetohydrodynamics (MHD) flow three independent constant helicities are reviewed while the helicity of magnetic potential is generalized for non-simply connected domains by inserting a special harmonic knot field in the dynamics of the magnetic potential. It is proved that the harmonic knot part of the vorticity

Initial eccentricity and constituent quark number scaling of elliptic flow in ideal and viscous dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaudhuri, A. K.

2010-04-15

In the Israel-Stewart theory of dissipative hydrodynamics, the scaling properties of elliptic flow in Au+Au collisions are studied. The initial energy density of the fluid was fixed to reproduce STAR data on phi-meson multiplicity in 0-5% Au+Au collisions such that, irrespective of fluid viscosity, entropy at the freeze-out is similar in ideal or in viscous evolution. The initial eccentricity or constituent quark number scaling is only approximate in ideal or minimally viscous (eta/s=1/4pi) fluid. Eccentricity scaling becomes nearly exact in more viscous fluid (eta/s>=0.12). However, in more viscous fluid, constituent quark number scaled elliptic flow for mesons and baryons splitsmore » into separate scaling functions. Simulated flows also do not exhibit 'universal scaling'; that is, elliptic flow scaled by the constituent quark number and charged particles v{sub 2} is not a single function of transverse kinetic energy scaled by the quark number. From a study of the violation of universal scaling, we obtain an estimate of quark-gluon plasma viscosity, eta/s=0.12+-0.03. The error is statistical only. The systematic error in eta/s could be as large.« less

RIS4E at Kilauea's December 1974 (D1974) Flow: Establishing the D1974 Flow as an Ideal Mars Analog

NASA Astrophysics Data System (ADS)

Young, K. E.; Bleacher, J. E.; Rogers, D.; McAdam, A.; Garry, W. B.; Scheidt, S. P.; Carter, L. M.; Glotch, T. D.

2015-12-01

The Kīlauea December 1974 (D1974) flow was emplaced from a series of en echelon fissures southwest of Kīlauea Caldera. In 6.5 hours the D1974 flow was emplaced over the Keanakāko`i ash member as a rapidly emplaced sheet flow. This flow has previously been used as a location for radar roughness studies due to the exposure of abrupt changes in surface texture ranging between smooth pāhoehoe, rubbly and slabby lavas and ´áā lava. When viewed in visible remote sensing images, this flow field displays dark and light toned areas that reveal sinuous patterns, streamlined islands, and rafted lava slabs and plates. The flow is an ideal location to study lava textures, textural relationships and the formation of non-traditional channels and associated features as analogs to characterizing the formation of channel networks on the flanks of martian volcanoes or rilles in the lunar mare. The D1974 flow is also positioned downwind from Kīlauea Caldera along the volcano's SW rift zone. D1974 lavas flowed across older, active fumaroles and have since been exposed to acid fog, rain, and other plume related processes. In 2008 the Kīlauea Caldera experienced an explosive event along the wall of Halemáumáu and has since displayed an active lava lake, thereby elevating the flow's exposure to processes related to volcanic gasses. Alteration products have therefore formed both in and around the older fumaroles (at the solfatara site) as well as being deposited as thin coatings over the entire length of the flow. These products are reminiscent of sulfate-rich materials that have been identified on Mars by several groups. Though these martian deposits have been identified and analyzed, their formation mechanism remains somewhat ambiguous. The D1974 flow represents an ideal analog with which to test various formation scenarios using a variety of field portable technologies, designed to analyze the alteration products in situ (thereby preserving their initial structures and

Computational-hydrodynamic studies of the Noh compressible flow problem using non-ideal equations of state

NASA Astrophysics Data System (ADS)

Honnell, Kevin; Burnett, Sarah; Yorke, Chloe'; Howard, April; Ramsey, Scott

2017-06-01

The Noh problem is classic verification problem in the field of compressible flows. Simple to conceptualize, it is nonetheless difficult for numerical codes to predict correctly, making it an ideal code-verification test bed. In its original incarnation, the fluid is a simple ideal gas; once validated, however, these codes are often used to study highly non-ideal fluids and solids. In this work the classic Noh problem is extended beyond the commonly-studied polytropic ideal gas to more realistic equations of state (EOS) including the stiff gas, the Nobel-Abel gas, and the Carnahan-Starling hard-sphere fluid, thus enabling verification studies to be performed on more physically-realistic fluids. Exact solutions are compared with numerical results obtained from the Lagrangian hydrocode FLAG, developed at Los Alamos. For these more realistic EOSs, the simulation errors decreased in magnitude both at the origin and at the shock, but also spread more broadly about these points compared to the ideal EOS. The overall spatial convergence rate remained first order.

Spiral blood flows in an idealized 180-degree curved artery model

NASA Astrophysics Data System (ADS)

Bulusu, Kartik V.; Kulkarni, Varun; Plesniak, Michael W.

2017-11-01

Understanding of cardiovascular flows has been greatly advanced by the Magnetic Resonance Velocimetry (MRV) technique and its potential for three-dimensional velocity encoding in regions of anatomic interest. The MRV experiments were performed on a 180-degree curved artery model using a Newtonian blood analog fluid at the Richard M. Lucas Center at Stanford University employing a 3 Tesla General Electric (Discovery 750 MRI system) whole body scanner with an eight-channel cardiac coil. Analysis in two regions of the model-artery was performed for flow with Womersley number=4.2. In the entrance region (or straight-inlet pipe) the unsteady pressure drop per unit length, in-plane vorticity and wall shear stress for the pulsatile, carotid artery-based flow rate waveform were calculated. Along the 180-degree curved pipe (curvature ratio =1/7) the near-wall vorticity and the stretching of the particle paths in the vorticity field are visualized. The resultant flow behavior in the idealized curved artery model is associated with parameters such as Dean number and Womersley number. Additionally, using length scales corresponding to the axial and secondary flow we attempt to understand the mechanisms leading to the formation of various structures observed during the pulsatile flow cycle. Supported by GW Center for Biomimetics and Bioinspired Engineering (COBRE), MRV measurements in collaboration with Prof. John K. Eaton and, Dr. Chris Elkins at Stanford University.

The Statistical Mechanics of Ideal MHD Turbulence

NASA Technical Reports Server (NTRS)

Shebalin, John V.

2003-01-01

Turbulence is a universal, nonlinear phenomenon found in all energetic fluid and plasma motion. In particular. understanding magneto hydrodynamic (MHD) turbulence and incorporating its effects in the computation and prediction of the flow of ionized gases in space, for example, are great challenges that must be met if such computations and predictions are to be meaningful. Although a general solution to the "problem of turbulence" does not exist in closed form, numerical integrations allow us to explore the phase space of solutions for both ideal and dissipative flows. For homogeneous, incompressible turbulence, Fourier methods are appropriate, and phase space is defined by the Fourier coefficients of the physical fields. In the case of ideal MHD flows, a fairly robust statistical mechanics has been developed, in which the symmetry and ergodic properties of phase space is understood. A discussion of these properties will illuminate our principal discovery: Coherent structure and randomness co-exist in ideal MHD turbulence. For dissipative flows, as opposed to ideal flows, progress beyond the dimensional analysis of Kolmogorov has been difficult. Here, some possible future directions that draw on the ideal results will also be discussed. Our conclusion will be that while ideal turbulence is now well understood, real turbulence still presents great challenges.

On the accuracy of Whitham's method. [for steady ideal gas flow past cones

NASA Technical Reports Server (NTRS)

Zahalak, G. I.; Myers, M. K.

1974-01-01

The steady flow of an ideal gas past a conical body is studied by the method of matched asymptotic expansions and by Whitham's method in order to assess the accuracy of the latter. It is found that while Whitham's method does not yield a correct asymptotic representation of the perturbation field to second order in regions where the flow ahead of the Mach cone of the apex is disturbed, it does correctly predict the changes of the second-order perturbation quantities across a shock (the first-order shock strength). The results of the analysis are illustrated by a special case of a flat, rectangular plate at incidence.

Similarity solutions for unsteady flow behind an exponential shock in a self-gravitating non-ideal gas with azimuthal magnetic field

NASA Astrophysics Data System (ADS)

Nath, G.; Pathak, R. P.; Dutta, Mrityunjoy

2018-01-01

Similarity solutions for the flow of a non-ideal gas behind a strong exponential shock driven out by a piston (cylindrical or spherical) moving with time according to an exponential law is obtained. Solutions are obtained, in both the cases, when the flow between the shock and the piston is isothermal or adiabatic. The shock wave is driven by a piston moving with time according to an exponential law. Similarity solutions exist only when the surrounding medium is of constant density. The effects of variation of ambient magnetic field, non-idealness of the gas, adiabatic exponent and gravitational parameter are worked out in detail. It is shown that the increase in the non-idealness of the gas or the adiabatic exponent of the gas or presence of magnetic field have decaying effect on the shock wave. Consideration of the isothermal flow and the self-gravitational field increase the shock strength. Also, the consideration of isothermal flow or the presence of magnetic field removes the singularity in the density distribution, which arises in the case of adiabatic flow. The result of our study may be used to interpret measurements carried out by space craft in the solar wind and in neighborhood of the Earth's magnetosphere.

Numerical Simulation of Nocturnal Drainage Flows in Idealized Valley-Tributary Systems.

NASA Astrophysics Data System (ADS)

O'Steen, Lance B.

2000-11-01

Numerical simulations of nocturnal drainage flow and transport in idealized valley-tributary systems are compared with the Atmospheric Science in Complex Terrain (ASCOT) meteorological field data and tracer studies from the Brush Creek valley of western Colorado. Much of the general valley-tributary flow behavior deduced from observations is qualitatively reproduced in the numerical results. The spatially complex, unsteady nature of the tributary flow found in the field data is also seen in the simulations. Oscillations in the simulated tributary flow are similar to some field observations. However, observed oscillations in the valley flow at the mouth of the tributary could not be reproduced in the numerical results. Thus, hypotheses of strongly coupled valley-tributary flow oscillations, based on field data, cannot be supported by these simulations. Along-valley mass flux calculations based on model results for the valley-tributary system indicate an increase of 5%-10% over a valley without a tributary. Enhanced valley mass fluxes were found from 8 km above the tributary to almost the valley mouth. However, the valley mass fluxes for topography with and without a tributary were nearly equal at the valley outflow. ASCOT field data suggested a tributary mass flow contribution of 5%-15% for a Brush Creek tributary of similar drainage area to the model tributary employed here. Numerical simulations of transport in the nocturnal valley-tributary flow strongly support ASCOT tracer studies in the Pack Canyon tributary of Brush Creek. These results suggest that the valley-tributary interaction can significantly increase plume dispersion under stable conditions. Overall, the simulation results presented here indicate that simple terrain geometries are able to capture many of the salient features of drainage flow in real valley-tributary systems.

Approximate Solutions for Ideal Dam-Break Sediment-Laden Flows on Uniform Slopes

NASA Astrophysics Data System (ADS)

Ni, Yufang; Cao, Zhixian; Borthwick, Alistair; Liu, Qingquan

2018-04-01

Shallow water hydro-sediment-morphodynamic (SHSM) models have been applied increasingly widely in hydraulic engineering and geomorphological studies over the past few decades. Analytical and approximate solutions are usually sought to verify such models and therefore confirm their credibility. Dam-break flows are often evoked because such flows normally feature shock waves and contact discontinuities that warrant refined numerical schemes to solve. While analytical and approximate solutions to clear-water dam-break flows have been available for some time, such solutions are rare for sediment transport in dam-break flows. Here we aim to derive approximate solutions for ideal dam-break sediment-laden flows resulting from the sudden release of a finite volume of frictionless, incompressible water-sediment mixture on a uniform slope. The approximate solutions are presented for three typical sediment transport scenarios, i.e., pure advection, pure sedimentation, and concurrent entrainment and deposition. Although the cases considered in this paper are not real, the approximate solutions derived facilitate suitable benchmark tests for evaluating SHSM models, especially presently when shock waves can be numerically resolved accurately with a suite of finite volume methods, while the accuracy of the numerical solutions of contact discontinuities in sediment transport remains generally poorer.

Numerical modelling of flow structures over idealized transverse aeolian dunes of varying geometry

NASA Astrophysics Data System (ADS)

Parsons, Daniel R.; Walker, Ian J.; Wiggs, Giles F. S.

2004-04-01

A Computational Fluid Dynamics (CFD) model (PHOENICS™ 3.5) previously validated for wind tunnel measurements is used to simulate the streamwise and vertical velocity flow fields over idealized transverse dunes of varying height ( h) and stoss slope basal length ( L). The model accurately reproduced patterns of: flow deceleration at the dune toe; stoss flow acceleration; vertical lift in the crest region; lee-side flow separation, re-attachment and reversal; and flow recovery distance. Results indicate that the flow field over transverse dunes is particularly sensitive to changes in dune height, with an increase in height resulting in flow deceleration at the toe, streamwise acceleration and vertical lift at the crest, and an increase in the extent of, and strength of reversed flows within, the lee-side separation cell. In general, the length of the separation zone varied from 3 to 15 h from the crest and increased over taller, steeper dunes. Similarly, the flow recovery distance ranged from 45 to >75 h and was more sensitive to changes in dune height. For the range of dune shapes investigated in this study, the differing effects of height and stoss slope length raise questions regarding the applicability of dune aspect ratio as a parameter for explaining airflow over transverse dunes. Evidence is also provided to support existing research on: streamline curvature and the maintenance of sand transport in the toe region; vertical lift in the crest region and its effect on grainfall delivery; relations between the turbulent shear layer and downward forcing of flow re-attachment; and extended flow recovery distances beyond the separation cell. Field validation is required to test these findings in natural settings. Future applications of the model will characterize turbulence and shear stress fields, examine the effects of more complex isolated dune forms and investigate flow over multiple dunes.

A fast numerical method for ideal fluid flow in domains with multiple stirrers

NASA Astrophysics Data System (ADS)

Nasser, Mohamed M. S.; Green, Christopher C.

2018-03-01

A collection of arbitrarily-shaped solid objects, each moving at a constant speed, can be used to mix or stir ideal fluid, and can give rise to interesting flow patterns. Assuming these systems of fluid stirrers are two-dimensional, the mathematical problem of resolving the flow field—given a particular distribution of any finite number of stirrers of specified shape and speed—can be formulated as a Riemann-Hilbert (R-H) problem. We show that this R-H problem can be solved numerically using a fast and accurate algorithm for any finite number of stirrers based around a boundary integral equation with the generalized Neumann kernel. Various systems of fluid stirrers are considered, and our numerical scheme is shown to handle highly multiply connected domains (i.e. systems of many fluid stirrers) with minimal computational expense.

Exact Solutions to Several Nonlinear Cases of Generalized Grad-Shafranov Equation for Ideal Magnetohydrodynamic Flows in Axisymmetric Domain

NASA Astrophysics Data System (ADS)

Adem, Abdullahi Rashid; Moawad, Salah M.

2018-05-01

In this paper, the steady-state equations of ideal magnetohydrodynamic incompressible flows in axisymmetric domains are investigated. These flows are governed by a second-order elliptic partial differential equation as a type of generalized Grad-Shafranov equation. The problem of finding exact equilibria to the full governing equations in the presence of incompressible mass flows is considered. Two different types of constraints on position variables are presented to construct exact solution classes for several nonlinear cases of the governing equations. Some of the obtained results are checked for their applications to magnetic confinement plasma. Besides, they cover many previous configurations and include new considerations about the nonlinearity of magnetic flux stream variables.

How important is non-ideal physics in simulations of sub-Eddington accretion on to spinning black holes?

NASA Astrophysics Data System (ADS)

Foucart, Francois; Chandra, Mani; Gammie, Charles F.; Quataert, Eliot; Tchekhovskoy, Alexander

2017-09-01

Black holes with accretion rates well below the Eddington rate are expected to be surrounded by low-density, hot, geometrically thick accretion discs. This includes the two black holes being imaged at subhorizon resolution by the Event Horizon Telescope. In these discs, the mean free path for Coulomb interactions between charged particles is large, and the accreting matter is a nearly collisionless plasma. Despite this, numerical simulations have so far modelled these accretion flows using ideal magnetohydrodynamics. Here, we present the first global, general relativistic, 3D simulations of accretion flows on to a Kerr black hole including the non-ideal effects most likely to affect the dynamics of the disc: the anisotropy between the pressure parallel and perpendicular to the magnetic field, and the heat flux along magnetic field lines. We show that for both standard and magnetically arrested discs, the pressure anisotropy is comparable to the magnetic pressure, while the heat flux remains dynamically unimportant. Despite this large pressure anisotropy, however, the time-averaged structure of the accretion flow is strikingly similar to that found in simulations treating the plasma as an ideal fluid. We argue that these similarities are largely due to the interchangeability of the viscous and magnetic shear stresses as long as the magnetic pressure is small compared to the gas pressure, and to the subdominant role of pressure/viscous effects in magnetically arrested discs. We conclude by highlighting outstanding questions in modelling the dynamics of low-collisionality accretion flows.

Simple equations to simulate closed-loop recycling liquid-liquid chromatography: Ideal and non-ideal recycling models.

PubMed

Kostanyan, Artak E

2015-12-04

The ideal (the column outlet is directly connected to the column inlet) and non-ideal (includes the effects of extra-column dispersion) recycling equilibrium-cell models are used to simulate closed-loop recycling counter-current chromatography (CLR CCC). Simple chromatogram equations for the individual cycles and equations describing the transport and broadening of single peaks and complex chromatograms inside the recycling closed-loop column for ideal and non-ideal recycling models are presented. The extra-column dispersion is included in the theoretical analysis, by replacing the recycling system (connecting lines, pump and valving) by a cascade of Nec perfectly mixed cells. To evaluate extra-column contribution to band broadening, two limiting regimes of recycling are analyzed: plug-flow, Nec→∞, and maximum extra-column dispersion, Nec=1. Comparative analysis of ideal and non-ideal models has shown that when the volume of the recycling system is less than one percent of the column volume, the influence of the extra-column processes on the CLR CCC separation may be neglected. Copyright © 2015 Elsevier B.V. All rights reserved.

Local invariants in non-ideal flows of neutral fluids and two-fluid plasmas

NASA Astrophysics Data System (ADS)

Zhu, Jian-Zhou

2018-03-01

The main objective is the locally invariant geometric object of any (magneto-)fluid dynamics with forcing and damping (nonideal), while more attention is paid to the untouched dynamical properties of two-fluid fashion. Specifically, local structures, beyond the well-known "frozen-in" to the barotropic flows of the generalized vorticities, of the two-fluid model of plasma flows are presented. More general non-barotropic situations are also considered. A modified Euler equation [T. Tao, "Finite time blowup for Lagrangian modifications of the three-dimensional Euler equation," Ann. PDE 2, 9 (2016)] is also accordingly analyzed and remarked from the angle of view of the two-fluid model, with emphasis on the local structures. The local constraints of high-order differential forms such as helicity, among others, find simple formulation for possible practices in modeling the dynamics. Thus, the Cauchy invariants equation [N. Besse and U. Frisch, "Geometric formulation of the Cauchy invariants for incompressible Euler flow in flat and curved spaces," J. Fluid Mech. 825, 412 (2017)] may be enabled to find applications in non-ideal flows. Some formal examples are offered to demonstrate the calculations, and particularly interestingly the two-dimensional-three-component (2D3C) or the 2D passive scalar problem presents that a locally invariant Θ = 2θζ, with θ and ζ being, respectively, the scalar value of the "vertical velocity" (or the passive scalar) and the "vertical vorticity," may be used as if it were the spatial density of the globally invariant helicity, providing a Lagrangian prescription to control the latter in some situations of studying its physical effects in rapidly rotating flows (ubiquitous in atmosphere of astrophysical objects) with marked 2D3C vortical modes or in purely 2D passive scalars.

A reactive flow model with coupled reaction kinetics for detonation and combustion in non-ideal explosives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, P.J.

1996-07-01

A new reactive flow model for highly non-ideal explosives and propellants is presented. These compositions, which contain large amounts of metal, upon explosion have reaction kinetics that are characteristic of both fast detonation and slow metal combustion chemistry. A reaction model for these systems was incorporated into the two-dimensional, finite element, Lagrangian hydrodynamic code, DYNA2D. A description of how to determine the model parameters is given. The use of the model and variations are applied to AP, Al, and nitramine underwater explosive and propellant systems.

Ideal hydrodynamics and elliptic flow at CERN Super Proton Synchrotron (SPS) energies: Importance of the initial conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petersen, Hannah; Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main; Bleicher, Marcus

2009-05-15

The elliptic flow excitation function calculated in a full (3+1) dimensional hybrid Boltzmann approach with an intermediate hydrodynamic stage for heavy ion reactions from GSI Schwerionen Synchrotron to the highest CERN Super Proton Synchrotron (SPS) energies is discussed in the context of the experimental data. In this study, we employ a hadron gas equation of state to investigate the differences in the dynamics and viscosity effects. The specific event-by-event setup with initial conditions and freeze-out from a nonequilibrium transport model allows for a direct comparison between ideal fluid dynamics and transport simulations. At higher SPS energies, where the pure transportmore » calculation cannot account for the high elliptic flow values, the smaller mean free path in the hydrodynamic evolution leads to higher elliptic flow values. In contrast to previous studies within pure hydrodynamics, the more realistic initial conditions employed here and the inclusion of a sequential final state hadronic decoupling provides results that are in line with the experimental data almost over the whole energy range from E{sub lab}=2-160A GeV. Thus, this new approach leads to a substantially different shape of the v{sub 2}/{epsilon} scaling curve as a function of (1/SdN{sub ch}/dy) in line with the experimental data compared to previous ideal hydrodynamic calculations. This hints at a strong influence of the initial conditions for the hydrodynamic evolution on the finally observed v{sub 2} values, thus questioning the standard interpretation that the hydrodynamic limit is only reached at BNL Relativistic Heavy Ion Collider energies.« less

On controlling nonlinear dissipation in high order filter methods for ideal and non-ideal MHD

NASA Technical Reports Server (NTRS)

Yee, H. C.; Sjogreen, B.

2004-01-01

The newly developed adaptive numerical dissipation control in spatially high order filter schemes for the compressible Euler and Navier-Stokes equations has been recently extended to the ideal and non-ideal magnetohydrodynamics (MHD) equations. These filter schemes are applicable to complex unsteady MHD high-speed shock/shear/turbulence problems. They also provide a natural and efficient way for the minimization of Div(B) numerical error. The adaptive numerical dissipation mechanism consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and leave the rest of the region free from numerical dissipation contamination. The numerical dissipation considered consists of high order linear dissipation for the suppression of high frequency oscillation and the nonlinear dissipative portion of high-resolution shock-capturing methods for discontinuity capturing. The applicable nonlinear dissipative portion of high-resolution shock-capturing methods is very general. The objective of this paper is to investigate the performance of three commonly used types of nonlinear numerical dissipation for both the ideal and non-ideal MHD.

Steady Secondary Flows Generated by Periodic Compression and Expansion of an Ideal Gas in a Pulse Tube

NASA Technical Reports Server (NTRS)

Lee, Jeffrey M.

1999-01-01

This study establishes a consistent set of differential equations for use in describing the steady secondary flows generated by periodic compression and expansion of an ideal gas in pulse tubes. Also considered is heat transfer between the gas and the tube wall of finite thickness. A small-amplitude series expansion solution in the inverse Strouhal number is proposed for the two-dimensional axisymmetric mass, momentum and energy equations. The anelastic approach applies when shock and acoustic energies are small compared with the energy needed to compress and expand the gas. An analytic solution to the ordered series is obtained in the strong temperature limit where the zeroth-order temperature is constant. The solution shows steady velocities increase linearly for small Valensi number and can be of order I for large Valensi number. A conversion of steady work flow to heat flow occurs whenever temperature, velocity or phase angle gradients are present. Steady enthalpy flow is reduced by heat transfer and is scaled by the Prandtl times Valensi numbers. Particle velocities from a smoke-wire experiment were compared with predictions for the basic and orifice pulse tube configurations. The theory accurately predicted the observed steady streaming.

Noise Production of an Idealized Two-Dimensional Fish School

NASA Astrophysics Data System (ADS)

Wagenhoffer, Nathan; Moored, Keith; Jaworski, Justin

2017-11-01

The analysis of quiet bio-inspired propulsive concepts requires a rapid, unified computational framework that integrates the coupled fluid-solid dynamics of swimmers and their wakes with the resulting noise generation. Such a framework is presented for two-dimensional flows, where the fluid motion is modeled by an unsteady boundary element method with a vortex-particle wake. The unsteady surface forces from the potential flow solver are then passed to an acoustic boundary element solver to predict the radiated sound in low-Mach-number flows. The coupled flow-acoustic solver is validated against canonical vortex-sound problems. A diamond arrangement of four airfoils are subjected to traveling wave kinematics representing a known idealized pattern for a school of fish, and the airfoil motion and inflow values are derived from the range of Strouhal values common to many natural swimmers. The coupled flow-acoustic solver estimates and analyzes the hydrodynamic performance and noise production of the idealized school of swimmers.

Effects of objectifying gaze on female cognitive performance: The role of flow experience and internalization of beauty ideals.

PubMed

Guizzo, Francesca; Cadinu, Mara

2017-06-01

Although previous research has demonstrated that objectification impairs female cognitive performance, no research to date has investigated the mechanisms underlying such decrement. Therefore, we tested the role of flow experience as one mechanism leading to performance decrement under sexual objectification. Gaze gender was manipulated by having male versus female experimenters take body pictures of female participants (N = 107) who then performed a Sustained Attention to Response Task. As predicted, a moderated mediation model showed that under male versus female gaze, higher internalization of beauty ideals was associated with lower flow, which in turn decreased performance. The implications of these results are discussed in relation to objectification theory and strategies to prevent sexually objectifying experiences. © 2016 The British Psychological Society.

Dynamic mode decomposition of Fontan hemodynamics in an idealized total cavopulmonary connection

NASA Astrophysics Data System (ADS)

Delorme, Yann T.; Kerlo, Anna-Elodie M.; Anupindi, Kameswararao; Rodefeld, Mark D.; Frankel, Steven H.

2014-08-01

Univentricular heart disease is the leading cause of death from any birth defect in the first year of life. Typically, patients have to undergo three open heart surgical procedures within the first few years of their lives to eventually directly connect the superior and inferior vena cavae to the left and right pulmonary arteries forming the total cavopulmonary connection (TCPC). The end result is a weak circulation where the single working ventricle pumps oxygenated blood to the body and de-oxygenated blood flows passively through the TCPC into the lungs. The fluid dynamics of the TCPC junction involve confined impinging jets resulting in a highly unstable flow, significant mechanical energy dissipation and undesirable pressure loss. Understanding and predicting such flows is important for improving the surgical procedure and for the design of mechanical cavopulmonary assist devices. In this study, dynamic mode decomposition (DMD) is used to analyze previously obtained stereoscopic particle imaging velocimetry (SPIV) data and large eddy simulation (LES) results for an idealized TCPC. Analysis of the DMD modes from the SPIV and LES serves to both highlight the unsteady vortical dynamics and the qualitative agreement between measurements and simulations.

Quantifying residual, eddy, and mean flow effects on mixing in an idealized circumpolar current

DOE PAGES

Wolfram, Phillip J.; Ringler, Todd D.

2017-07-13

Meridional diffusivity is assessed in this paper for a baroclinically unstable jet in a high-latitudeIdealized Circumpolar Current (ICC) using the Model for Prediction Across Scales-Ocean (MPAS-O) and the online Lagrangian In-situ Global High-performance particle Tracking (LIGHT) diagnostic via space-time dispersion of particle clusters over 120 monthly realizations of O(10 6) particles on 11 potential density surfaces. Diffusivity in the jet reaches values of O(6000 m 2 s -1) and is largest near the critical layer supporting mixing suppression and critical layer theory. Values in the vicinity of the shelf break are suppressed to O(100 m 2 s -1) due tomore » the presence of westward slope front currents. Diffusivity attenuates less rapidly with depth in the jet than both eddy velocity and kinetic energy scalings would suggest. Removal of the mean flow via high-pass filtering shifts the nonlinear parameter (ratio of the eddy velocity to eddy phase speed) into the linear wave regime by increasing the eddy phase speed via the depth-mean flow. Low-pass filtering, in contrast, quantifies the effect of mean shear. Diffusivity is decomposed into mean flow shear, linear waves, and the residual nonhomogeneous turbulence components, where turbulence dominates and eddy-produced filamentation strained by background mean shear enhances mixing, accounting for ≥ 80% of the total diffusivity relative to mean shear [O(100 m 2 s -1)], linear waves [O(1000 m 2 s -1)], and undecomposed full diffusivity [O(6000 m 2 s -1)]. Finally, diffusivity parameterizations accounting for both the nonhomogeneous turbulence residual and depth variability are needed.« less

Experimental characterization of powered Fontan hemodynamics in an idealized total cavopulmonary connection model

NASA Astrophysics Data System (ADS)

Kerlo, Anna-Elodie M.; Delorme, Yann T.; Xu, Duo; Frankel, Steven H.; Giridharan, Guruprasad A.; Rodefeld, Mark D.; Chen, Jun

2013-08-01

A viscous impeller pump (VIP) based on the Von Karman viscous pump is specifically designed to provide cavopulmonary assist in a univentricular Fontan circulation. The technology will make it possible to biventricularize the univentricular Fontan circulation. Ideally, it will reduce the number of surgeries required for Fontan conversion from three to one early in life, while simultaneously improving physiological conditions. Later in life, it will provide a currently unavailable means of chronic support for adolescent and adult patients with failing Fontan circulations. Computational fluid dynamics simulations demonstrate that the VIP can satisfactorily augment cavopulmonary blood flow in an idealized total cavopulmonary connection (TCPC). When the VIP is deployed at the TCPC intersection as a static device, it stabilizes the four-way flow pattern and is not obstructive to the flow. Experimental studies are carried out to assess performance, hemodynamic characteristics, and flow structures of the VIP in an idealized TCPC model. Stereoscopic particle image velocimetry is applied using index-matched blood analog. Results show excellent performance of the VIP without cavitation and with reduction of the energy losses. The non-rotating VIP smoothes and accelerates flow, and decreases stresses and turbulence in the TCPC. The rotating VIP generates the desired low-pressure Fontan flow augmentation (0-10 mmHg) while maintaining acceptable stress thresholds.

Adjustment of Turbulent Boundary-Layer Flow to Idealized Urban Surfaces: A Large-Eddy Simulation Study

NASA Astrophysics Data System (ADS)

Cheng, Wai-Chi; Porté-Agel, Fernando

2015-05-01

Large-eddy simulations (LES) are performed to simulate the atmospheric boundary-layer (ABL) flow through idealized urban canopies represented by uniform arrays of cubes in order to better understand atmospheric flow over rural-to-urban surface transitions. The LES framework is first validated with wind-tunnel experimental data. Good agreement between the simulation results and the experimental data are found for the vertical and spanwise profiles of the mean velocities and velocity standard deviations at different streamwise locations. Next, the model is used to simulate ABL flows over surface transitions from a flat homogeneous terrain to aligned and staggered arrays of cubes with height . For both configurations, five different frontal area densities , equal to 0.028, 0.063, 0.111, 0.174 and 0.250, are considered. Within the arrays, the flow is found to adjust quickly and shows similar structure to the wake of the cubes after the second row of cubes. An internal boundary layer is identified above the cube arrays and found to have a similar depth in all different cases. At a downstream location where the flow immediately above the cube array is already adjusted to the surface, the spatially-averaged velocity is found to have a logarithmic profile in the vertical. The values of the displacement height are found to be quite insensitive to the canopy layout (aligned vs. staggered) and increase roughly from to as increases from 0.028 to 0.25. Relatively larger values of the aerodynamic roughness length are obtained for the staggered arrays, compared with the aligned cases, and a maximum value of is found at for both configurations. By explicitly calculating the drag exerted by the cubes on the flow and the drag coefficients of the cubes using our LES results, and comparing the results with existing theoretical expressions, we show that the larger values of for the staggered arrays are related to the relatively larger drag coefficients of the cubes for that

Sequential Ideal-Observer Analysis of Visual Discriminations.

ERIC Educational Resources Information Center

Geisler, Wilson S.

1989-01-01

A new analysis, based on the concept of the ideal observer in signal detection theory, is described. It allows: tracing of the flow of discrimination information through the initial physiological stages of visual processing for arbitrary spatio-chromatic stimuli, and measurement of the information content of said visual stimuli. (TJH)

Idealization in Chemistry: Pure Substance and Laboratory Product

ERIC Educational Resources Information Center

Fernández-González, Manuel

2013-01-01

This article analyzes the concept of idealization in chemistry and the role played by pure substance and laboratory product. This topic has evident repercussions in the educational contexts that are applied to the science classroom, which are highlighted throughout the text. A common structure for knowledge construction is proposed for both…

Research highlights: increasing paper possibilities.

PubMed

Wu, Chueh-Yu; Adeyiga, Oladunni; Lin, Jonathan; Di Carlo, Dino

2014-09-07

In this issue we highlight three recent papers that demonstrate new strategies to extend the capabilities of paper microfluidics. Paper (a mesh of porous fibers) has a long history as a substrate to perform biomolecular assays. Traditional lateral flow immunoassays (LFAs) are widely used for rapid diagnostic tests, and perform well when a yes or no answer is required and the analyte of interest is at relatively high concentrations. High concentrations are required because usually only a small volume of analyte-containing fluid flows past the detection region, leading to a limited signal. Further, the small pores within paper matrices prevent the use of paper to control the flow of larger particles and cells, limiting the use of paper microfluidics for cell-based diagnostics. The work we highlight addresses these important unmet challenges in paper microfluidics: enriching low concentration analytes to a higher concentration in a smaller volume that can be processed effectively, and using paper to pump flows in larger channels amenable to cells. Applying these new approaches may allow diagnosis of disease states currently technically unachievable using current LFA systems, while maintaining many of the "un-instrumented" advantages of an assay on self-wicking paper.

Hazardous materials highlights : 2007 Commodity Flow Survey

DOT National Transportation Integrated Search

2011-01-01

Hazardous materials movement through the Nations transportation network in 2007 remained relatively unchanged from 2002 measures, according to data from the 2007 Commodity Flow Survey (CFS), released in 2010. The estimated 2.2 billion tons of haza...

Media-portrayed idealized images, body shame, and appearance anxiety.

PubMed

Monro, Fiona; Huon, Gail

2005-07-01

This study was designed to determine the effects of media-portrayed idealized images on young women's body shame and appearance anxiety, and to establish whether the effects depend on advertisement type and on participant self-objectification. Participants were 39 female university students. Twenty-four magazine advertisements comprised 12 body-related and 12 non-body-related products, one half of each with, and the other one half without, idealized images. Preexposure and post exposure body shame and appearance anxiety measures were recorded. Appearance anxiety increased after viewing advertisements featuring idealized images. There was also a significant interaction between self-objectification level and idealized body (presence vs. absence). No differences emerged for body-related compared with non-body-related product advertisements. The only result for body shame was a main effect for time. Participants' body shame increased after exposure to idealized images, irrespective of advertisement type. Although our findings reveal that media-portrayed idealized images detrimentally affect the body image of young women, they highlight the individual differences in vulnerability and the different effects for different components of body image. These results are discussed in terms of their implications for the prevention and early intervention of body image and dieting-related disorders. ( Copyright 2005 by Wiley Periodicals, Inc

1993 commodity flow survey : United States highlights

DOT National Transportation Integrated Search

1997-02-01

This report summarizes information from the 1993 Commodity Flow Survey (CFS) released in 1996 by the Bureau of the Census. The report presents data on domestic shipments of commodities by value and weight, destination by value and weight, mode of tra...

Esophageal aerodynamics in an idealized experimental model of tracheoesophageal speech

NASA Astrophysics Data System (ADS)

Erath, Byron D.; Hemsing, Frank S.

2016-03-01

Flow behavior is investigated in the esophageal tract in an idealized experimental model of tracheoesophageal speech. The tracheoesophageal prosthesis is idealized as a first-order approximation using a straight, constant diameter tube. The flow is scaled according to Reynolds, Strouhal, and Euler numbers to ensure dynamic similarity. Flow pulsatility is produced by a driven orifice that approximates the kinematics of the pharyngoesophageal segment during tracheoesophageal speech. Particle image velocimetry data are acquired in three orthogonal planes as the flow exits the model prosthesis and enters the esophageal tract. Contrary to prior investigations performed in steady flow with the prosthesis oriented in-line with the flow direction, the fluid dynamics are shown to be highly unsteady, suggesting that the esophageal pressure field will be similarly complex. A large vortex ring is formed at the inception of each phonatory cycle, followed by the formation of a persistent jet. This vortex ring appears to remain throughout the entire cycle due to the continued production of vorticity resulting from entrainment between the prosthesis jet and the curved esophageal walls. Mean flow in the axial direction of the esophagus produces significant stretching of the vortex throughout the phonatory cycle. The stagnation point created by the jet impinging on the esophageal wall varies throughout the cycle due to fluctuations in the jet trajectory, which most likely arises due to flow separation within the model prosthesis. Applications to tracheoesophageal speech, including shortcomings of the model and proposed future plans, are discussed.

The ideal Kolmogorov inertial range and constant

NASA Technical Reports Server (NTRS)

Zhou, YE

1993-01-01

The energy transfer statistics measured in numerically simulated flows are found to be nearly self-similar for wavenumbers in the inertial range. Using the measured self-similar form, an 'ideal' energy transfer function and the corresponding energy flux rate were deduced. From this flux rate, the Kolmogorov constant was calculated to be 1.5, in excellent agreement with experiments.

Numerical solutions of ideal quantum gas dynamical flows governed by semiclassical ellipsoidal-statistical distribution.

PubMed

Yang, Jaw-Yen; Yan, Chih-Yuan; Diaz, Manuel; Huang, Juan-Chen; Li, Zhihui; Zhang, Hanxin

2014-01-08

The ideal quantum gas dynamics as manifested by the semiclassical ellipsoidal-statistical (ES) equilibrium distribution derived in Wu et al. (Wu et al . 2012 Proc. R. Soc. A 468 , 1799-1823 (doi:10.1098/rspa.2011.0673)) is numerically studied for particles of three statistics. This anisotropic ES equilibrium distribution was derived using the maximum entropy principle and conserves the mass, momentum and energy, but differs from the standard Fermi-Dirac or Bose-Einstein distribution. The present numerical method combines the discrete velocity (or momentum) ordinate method in momentum space and the high-resolution shock-capturing method in physical space. A decoding procedure to obtain the necessary parameters for determining the ES distribution is also devised. Computations of two-dimensional Riemann problems are presented, and various contours of the quantities unique to this ES model are illustrated. The main flow features, such as shock waves, expansion waves and slip lines and their complex nonlinear interactions, are depicted and found to be consistent with existing calculations for a classical gas.

Numerical solutions of ideal quantum gas dynamical flows governed by semiclassical ellipsoidal-statistical distribution

PubMed Central

Yang, Jaw-Yen; Yan, Chih-Yuan; Diaz, Manuel; Huang, Juan-Chen; Li, Zhihui; Zhang, Hanxin

2014-01-01

The ideal quantum gas dynamics as manifested by the semiclassical ellipsoidal-statistical (ES) equilibrium distribution derived in Wu et al. (Wu et al. 2012 Proc. R. Soc. A 468, 1799–1823 (doi:10.1098/rspa.2011.0673)) is numerically studied for particles of three statistics. This anisotropic ES equilibrium distribution was derived using the maximum entropy principle and conserves the mass, momentum and energy, but differs from the standard Fermi–Dirac or Bose–Einstein distribution. The present numerical method combines the discrete velocity (or momentum) ordinate method in momentum space and the high-resolution shock-capturing method in physical space. A decoding procedure to obtain the necessary parameters for determining the ES distribution is also devised. Computations of two-dimensional Riemann problems are presented, and various contours of the quantities unique to this ES model are illustrated. The main flow features, such as shock waves, expansion waves and slip lines and their complex nonlinear interactions, are depicted and found to be consistent with existing calculations for a classical gas. PMID:24399919

The predictive validity of ideal partner preferences: a review and meta-analysis.

PubMed

Eastwick, Paul W; Luchies, Laura B; Finkel, Eli J; Hunt, Lucy L

2014-05-01

A central element of interdependence theory is that people have standards against which they compare their current outcomes, and one ubiquitous standard in the mating domain is the preference for particular attributes in a partner (ideal partner preferences). This article reviews research on the predictive validity of ideal partner preferences and presents a new integrative model that highlights when and why ideals succeed or fail to predict relational outcomes. Section 1 examines predictive validity by reviewing research on sex differences in the preference for physical attractiveness and earning prospects. Men and women reliably differ in the extent to which these qualities affect their romantic evaluations of hypothetical targets. Yet a new meta-analysis spanning the attraction and relationships literatures (k = 97) revealed that physical attractiveness predicted romantic evaluations with a moderate-to-strong effect size (r = ∼.40) for both sexes, and earning prospects predicted romantic evaluations with a small effect size (r = ∼.10) for both sexes. Sex differences in the correlations were small (r difference = .03) and uniformly nonsignificant. Section 2 reviews research on individual differences in ideal partner preferences, drawing from several theoretical traditions to explain why ideals predict relational evaluations at different relationship stages. Furthermore, this literature also identifies alternative measures of ideal partner preferences that have stronger predictive validity in certain theoretically sensible contexts. Finally, a discussion highlights a new framework for conceptualizing the appeal of traits, the difference between live and hypothetical interactions, and the productive interplay between mating research and broader psychological theories.

Not All Ideals are Equal: Intrinsic and Extrinsic Ideals in Relationships.

PubMed

Rodriguez, Lindsey M; Hadden, Benjamin W; Knee, C Raymond

2015-03-01

The ideal standards model suggests that greater consistency between ideal standards and actual perceptions of one's relationship predicts positive relationship evaluations; however, no research has evaluated whether this differs across types of ideals. A self-determination theory perspective was derived to test whether satisfaction of intrinsic ideals buffers the importance of extrinsic ideals. Participants (N=195) in committed relationships directly and indirectly reported the extent to which their partner met their ideal on two dimensions: intrinsic (e.g., warm, intimate) and extrinsic (e.g., attractive, successful). Relationship need fulfillment and relationship quality were also assessed. Hypotheses were largely supported, such that satisfaction of intrinsic ideals more strongly predicted relationship functioning, and satisfaction of intrinsic ideals buffered the relevance of extrinsic ideals for outcomes.

Not All Ideals are Equal: Intrinsic and Extrinsic Ideals in Relationships

PubMed Central

Rodriguez, Lindsey M.; Hadden, Benjamin W.; Knee, C. Raymond

2015-01-01

The ideal standards model suggests that greater consistency between ideal standards and actual perceptions of one’s relationship predicts positive relationship evaluations; however, no research has evaluated whether this differs across types of ideals. A self-determination theory perspective was derived to test whether satisfaction of intrinsic ideals buffers the importance of extrinsic ideals. Participants (N=195) in committed relationships directly and indirectly reported the extent to which their partner met their ideal on two dimensions: intrinsic (e.g., warm, intimate) and extrinsic (e.g., attractive, successful). Relationship need fulfillment and relationship quality were also assessed. Hypotheses were largely supported, such that satisfaction of intrinsic ideals more strongly predicted relationship functioning, and satisfaction of intrinsic ideals buffered the relevance of extrinsic ideals for outcomes. PMID:25821396

An Idealized Direct-Contact Biomass Pyrolysis Reactor Model

NASA Technical Reports Server (NTRS)

Miller, R. S.; Bellan, J.

1996-01-01

A numerical study is performed in order to assess the performance of biomass pyrolysis reactors which utilize direct particle-wall thermal conduction heating. An idealized reactor configuration consisting of a flat-plate turbulent boundary layer flow with particle convection along the heated wall and incorporating particle re-entrainment is considered.

Compressible Flow Toolbox

NASA Technical Reports Server (NTRS)

Melcher, Kevin J.

2006-01-01

The Compressible Flow Toolbox is primarily a MATLAB-language implementation of a set of algorithms that solve approximately 280 linear and nonlinear classical equations for compressible flow. The toolbox is useful for analysis of one-dimensional steady flow with either constant entropy, friction, heat transfer, or Mach number greater than 1. The toolbox also contains algorithms for comparing and validating the equation-solving algorithms against solutions previously published in open literature. The classical equations solved by the Compressible Flow Toolbox are as follows: The isentropic-flow equations, The Fanno flow equations (pertaining to flow of an ideal gas in a pipe with friction), The Rayleigh flow equations (pertaining to frictionless flow of an ideal gas, with heat transfer, in a pipe of constant cross section), The normal-shock equations, The oblique-shock equations, and The expansion equations.

Sex Education and Ideals

ERIC Educational Resources Information Center

de Ruyter, Doret J.; Spiecker, Ben

2008-01-01

This article argues that sex education should include sexual ideals. Sexual ideals are divided into sexual ideals in the strict sense and sexual ideals in the broad sense. It is argued that ideals that refer to the context that is deemed to be most ideal for the gratification of sexual ideals in the strict sense are rightfully called sexual…

Media-portrayed idealized images, self-objectification, and eating behavior.

PubMed

Monro, Fiona J; Huon, Gail F

2006-11-01

This study examined the effects of media-portrayed idealized images on young women's eating behavior. The study compared the effects for high and low self-objectifiers. 72 female university students participated in this experiment. Six magazine advertisements featuring idealized female models were used as the experimental stimuli, and the same six advertisements with the idealized body digitally removed became the control stimuli. Eating behavior was examined using a classic taste test that involved both sweet and savory food. Participants' restraint status was assessed. We found that total food intake after exposure was the same in the body present and absent conditions. There were also no differences between high and low self-objectifiers' total food intake. However, for the total amount of food consumed and for sweet food there were significant group by condition interaction effects. High self-objectifiers ate more food in the body present than the body absent condition. In contrast, low self-objectifiers ate more food in the body absent than in the body present condition. Restraint status was not found to moderate the relationship between exposure to idealized images the amount of food consumed. Our results indicate that exposure to media-portrayed idealized images can lead to changes in eating behavior and highlight the complexity of the association between idealized image exposure and eating behavior. These results are discussed in terms of their implications for the prevention of dieting-related disorders.

Wind Tunnel Study on Flows over Various Two-dimensional Idealized Urban-liked Surfaces

NASA Astrophysics Data System (ADS)

Ho, Yat-Kiu; Liu, Chun-Ho

2013-04-01

Extensive human activities (e.g. increased traffic emissions) emit a wide range of pollutants resulting in poor urban area air quality. Unlike open, flat and homogenous rural terrain, urban surface is complicated by the presence of buildings, obstacles and narrow streets. The irregular urban surfaces thus form a random roughness that further modifies the near-surface flows and pollutant dispersion. In this study, a physical modelling approach is employed to commence a series of wind tunnel experiments to study the urban-area air pollution problems. The flow characteristics over different hypothetical urban roughness surfaces were studied in a wind tunnel in isothermal conditions. Preliminary experiments were conducted based on six types of idealized two-dimensional (2D) street canyon models with various building-height-to-street-width (aspect) ratios (ARs) 1, 1/2, 1/4, 1/8, 1/10 and 1/12. The main instrumentation is an in-house 90o X-hotwire anemometry. In each set of configuration, a sampling street canyon was selected near the end of the streamwise domain. Its roof level, i.e. the transverse between the mid points of the upstream and downstream buildings, was divided into eight segments. The measurements were then recorded on the mid-plane of the spannwise domain along the vertical profile (from building roof level to the ceiling of wind tunnel) of the eight segments. All the data acquisition processes were handled by the NI data acquisition modules, NI 9239 and CompactDAQ-9188 hardware. Velocity calculation was carried out in the post-processing stage on a digital computer. The two-component flow velocities and velocity fluctuations were calculated at each sampling points, therefore, for each model, a streamwise average of eight vertical profiles of mean velocity and velocity fluctuations was presented. A plot of air-exchange rate (ACH) against ARs was also presented in order to examine the ventilation performance of different tested models. Preliminary results

Semiempirical method of determining flow coefficients for pitot rake mass flow rate measurements

NASA Technical Reports Server (NTRS)

Trefny, C. J.

1985-01-01

Flow coefficients applicable to area-weighted pitot rake mass flow rate measurements are presented for fully developed, turbulent flow in an annulus. A turbulent velocity profile is generated semiempirically for a given annulus hub-to-tip radius ratio and integrated numerically to determine the ideal mass flow rate. The calculated velocities at each probe location are then summed, and the flow rate as indicated by the rake is obtained. The flow coefficient to be used with the particular rake geometry is subsequently obtained by dividing the ideal flow rate by the rake-indicated flow rate. Flow coefficients ranged from 0.903 for one probe placed at a radius dividing two equal areas to 0.984 for a 10-probe area-weighted rake. Flow coefficients were not a strong function of annulus hub-to-tip radius ratio for rakes with three or more probes. The semiempirical method used to generate the turbulent velocity profiles is described in detail.

Limitations of the ideal phase-Doppler system: Extension to spatially and temporally inhomogeneous particle flows with an application to diesel sprays

NASA Astrophysics Data System (ADS)

Marx, K. D.; Edwards, C. F.

1992-12-01

The effect of the single-particle constraint on the response of phase-Doppler instruments is determined for particle flows which are spatially nonuniform and time-dependent. Poisson statistics are applied to particle positions and arrival times within the phase-Doppler probe volume to determine the probability that a particle is measured successfully. It is shown that the single-particle constraint can be viewed as applying spatial and temporal filters to the particle flow. These filters have the same meaning as those that were defined previously for uniform, steady-state sprays, but in space- and time-dependent form. Criteria are developed for determining when a fully inhomogeneous analysis of a flow is required and when a quasi-steady analysis will suffice. A new bias due to particle arrival time displacement is identified and the conditions under which it must be considered are established. The present work provides the means to rigorously investigate the response of phase-Doppler measurement systems to transient sprays such as those which occur in diesel engines. To this end, the results are applied to a numerical simulation of a diesel spray. The calculated hypothetical response of the ideal instrument provides a quantitative demonstration of the regimes within which measurements can accurately be made in such sprays.

Dynamics and stability of a 2D ideal vortex under external strain

NASA Astrophysics Data System (ADS)

Hurst, N. C.; Danielson, J. R.; Dubin, D. H. E.; Surko, C. M.

2017-11-01

The behavior of an initially axisymmetric 2D ideal vortex under an externally imposed strain flow is studied experimentally. The experiments are carried out using electron plasmas confined in a Penning-Malmberg trap; here, the dynamics of the plasma density transverse to the field are directly analogous to the dynamics of vorticity in a 2D ideal fluid. An external strain flow is applied using boundary conditions in a way that is consistent with 2D fluid dynamics. Data are compared to predictions from a theory assuming a piecewise constant elliptical vorticity distribution. Excellent agreement is found for quasi-flat profiles, whereas the dynamics of smooth profiles feature modified stability limits and inviscid damping of periodic elliptical distortions. This work supported by U.S. DOE Grants DE-SC0002451 and DE-SC0016532, and NSF Grant PHY-1414570.

Ideals versus reality: Are weight ideals associated with weight change in the population?

PubMed

Kärkkäinen, Ulla; Mustelin, Linda; Raevuori, Anu; Kaprio, Jaakko; Keski-Rahkonen, Anna

2016-04-01

To quantify weight ideals of young adults and to examine whether the discrepancy between actual and ideal weight is associated with 10-year body mass index (BMI) change in the population. This study comprised 4,964 adults from the prospective population-based FinnTwin16 study. They reported their actual and ideal body weight at age 24 (range 22-27) and 10 years later (attrition 24.6%). The correlates of discrepancy between actual and ideal body weight and the impact on subsequent BMI change were examined. The discrepancy between actual and ideal weight at 24 years was on average 3.9 kg (1.4 kg/m(2) ) among women and 1.2 kg (0.4 kg/m(2) ) among men. On average, participants gained weight during follow-up irrespective of baseline ideal weight: women ¯x = +4.8 kg (1.7 kg/m(2) , 95% CI 1.6-1.9 kg/m(2) ), men ¯x = +6.3 kg (2.0 kg/m(2) , 95% CI 1.8-2.1 kg/m(2) ). Weight ideals at 24 years were not correlated with 10-year weight change. At 34 years, just 13.2% of women and 18.9% of men were at or below the weight they had specified as their ideal weight at 24 years. Women and men adjusted their ideal weight upward over time. Irrespective of ideal weight at baseline, weight gain was nearly universal. Weight ideals were shifted upward over time. © 2016 The Obesity Society.

Finite-Difference Solution for Laminar or Turbulent Boundary Layer Flow over Axisymmetric Bodies with Ideal Gas, CF4, or Equilibrium Air Chemistry

NASA Technical Reports Server (NTRS)

Hamilton, H. Harris, II; Millman, Daniel R.; Greendyke, Robert B.

1992-01-01

A computer code was developed that uses an implicit finite-difference technique to solve nonsimilar, axisymmetric boundary layer equations for both laminar and turbulent flow. The code can treat ideal gases, air in chemical equilibrium, and carbon tetrafluoride (CF4), which is a useful gas for hypersonic blunt-body simulations. This is the only known boundary layer code that can treat CF4. Comparisons with experimental data have demonstrated that accurate solutions are obtained. The method should prove useful as an analysis tool for comparing calculations with wind tunnel experiments and for making calculations about flight vehicles where equilibrium air chemistry assumptions are valid.

Finite-difference solution for laminar or turbulent boundary layer flow over axisymmetric bodies with ideal gas, CF4, or equilibrium air chemistry

NASA Astrophysics Data System (ADS)

Hamilton, H. Harris, II; Millman, Daniel R.; Greendyke, Robert B.

1992-12-01

A computer code was developed that uses an implicit finite-difference technique to solve nonsimilar, axisymmetric boundary layer equations for both laminar and turbulent flow. The code can treat ideal gases, air in chemical equilibrium, and carbon tetrafluoride (CF4), which is a useful gas for hypersonic blunt-body simulations. This is the only known boundary layer code that can treat CF4. Comparisons with experimental data have demonstrated that accurate solutions are obtained. The method should prove useful as an analysis tool for comparing calculations with wind tunnel experiments and for making calculations about flight vehicles where equilibrium air chemistry assumptions are valid.

(Fuzzy) Ideals of BN-Algebras

PubMed Central

Walendziak, Andrzej

2015-01-01

The notions of an ideal and a fuzzy ideal in BN-algebras are introduced. The properties and characterizations of them are investigated. The concepts of normal ideals and normal congruences of a BN-algebra are also studied, the properties of them are displayed, and a one-to-one correspondence between them is presented. Conditions for a fuzzy set to be a fuzzy ideal are given. The relationships between ideals and fuzzy ideals of a BN-algebra are established. The homomorphic properties of fuzzy ideals of a BN-algebra are provided. Finally, characterizations of Noetherian BN-algebras and Artinian BN-algebras via fuzzy ideals are obtained. PMID:26125050

Chomskyan Cognitivism and Linguistic: Irreproachable Ideals for Educational Psychology and Designing Learning

ERIC Educational Resources Information Center

Paleeri, Sankaranarayanan

2011-01-01

This paper makes an attempt to highlight the significance of Chomskyan concepts of linguistic and cognitivism in restructuring educational ideals and directions regarding learning in Educational Psychology. His specific views on educational aspects are the need of the hour in education scenario especially in the context of globalization. This…

Shock formation and the ideal shape of ramp compression waves

NASA Astrophysics Data System (ADS)

Swift, Damian C.; Kraus, Richard G.; Loomis, Eric N.; Hicks, Damien G.; McNaney, James M.; Johnson, Randall P.

2008-12-01

We derive expressions for shock formation based on the local curvature of the flow characteristics during dynamic compression. Given a specific ramp adiabat, calculated for instance from the equation of state for a substance, the ideal nonlinear shape for an applied ramp loading history can be determined. We discuss the region affected by lateral release, which can be presented in compact form for the ideal loading history. Example calculations are given for representative metals and plastic ablators. Continuum dynamics (hydrocode) simulations were in good agreement with the algebraic forms. Example applications are presented for several classes of laser-loading experiment, identifying conditions where shocks are desired but not formed, and where long-duration ramps are desired.

Symmetry breaking in optimal timing of traffic signals on an idealized two-way street.

PubMed

Panaggio, Mark J; Ottino-Löffler, Bertand J; Hu, Peiguang; Abrams, Daniel M

2013-09-01

Simple physical models based on fluid mechanics have long been used to understand the flow of vehicular traffic on freeways; analytically tractable models of flow on an urban grid, however, have not been as extensively explored. In an ideal world, traffic signals would be timed such that consecutive lights turned green just as vehicles arrived, eliminating the need to stop at each block. Unfortunately, this "green-wave" scenario is generally unworkable due to frustration imposed by competing demands of traffic moving in different directions. Until now this has typically been resolved by numerical simulation and optimization. Here, we develop a theory for the flow in an idealized system consisting of a long two-way road with periodic intersections. We show that optimal signal timing can be understood analytically and that there are counterintuitive asymmetric solutions to this signal coordination problem. We further explore how these theoretical solutions degrade as traffic conditions vary and automotive density increases.

Symmetry breaking in optimal timing of traffic signals on an idealized two-way street

NASA Astrophysics Data System (ADS)

Panaggio, Mark J.; Ottino-Löffler, Bertand J.; Hu, Peiguang; Abrams, Daniel M.

2013-09-01

Simple physical models based on fluid mechanics have long been used to understand the flow of vehicular traffic on freeways; analytically tractable models of flow on an urban grid, however, have not been as extensively explored. In an ideal world, traffic signals would be timed such that consecutive lights turned green just as vehicles arrived, eliminating the need to stop at each block. Unfortunately, this “green-wave” scenario is generally unworkable due to frustration imposed by competing demands of traffic moving in different directions. Until now this has typically been resolved by numerical simulation and optimization. Here, we develop a theory for the flow in an idealized system consisting of a long two-way road with periodic intersections. We show that optimal signal timing can be understood analytically and that there are counterintuitive asymmetric solutions to this signal coordination problem. We further explore how these theoretical solutions degrade as traffic conditions vary and automotive density increases.

What Do You Want in a Marriage? Examining Marriage Ideals in Taiwan and the United States.

PubMed

Lam, Ben C P; Cross, Susan E; Wu, Tsui-Feng; Yeh, Kuang-Hui; Wang, Yi-Chao; Su, Jenny C

2016-06-01

Four studies investigated ideal standards for one's marital partner and relationship held by Taiwan Chinese and European Americans. We first generated a list of attributes that tapped lay representations of marriage ideals based on free responses from Chinese and European Americans, and we uncovered attributes describing extended family that were overlooked in Western research (Study 1). We found similar ideal knowledge structures across the two cultural groups; importantly, Chinese prioritized ideals denoting financial resources and extended family to a greater extent than did European Americans (Study 2). These cultural differences were explained by interdependent self-construal (Study 3). Finally, the agreement between ideals and perceptions of current partner/relationship was related to positive relationship outcomes in both cultural groups (Study 4). Our research highlights both cultural similarities and differences in the content, structure, endorsement, and evaluative functions of ideals in Chinese and Western cultural contexts. © 2016 by the Society for Personality and Social Psychology, Inc.

Lecture Series "Boundary Layer Theory". Part I - Laminar Flows. Part 1; Laminar Flows

NASA Technical Reports Server (NTRS)

Schlichting, H.

1949-01-01

In the lecture series starting today author want to give a survey of a field of aerodynamics which has for a number of years been attracting an ever growing interest. The subject is the theory of flows with friction, and, within that field, particularly the theory of friction layers, or boundary layers. A great many considerations of aerodynamics are based on the ideal fluid, that is the frictionless incompressibility and fluid. By neglect of compressibility and friction the extensive mathematical theory of the ideal fluid, (potential theory) has been made possible. Actual liquids and gases satisfy the condition of incomressibility rather well if the velocities are not extremely high or, more accurately, if they are small in comparison with sonic velocity. For air, for instance, the change in volume due to compressibility amounts to about 1 percent for a velocity of 60 meters per second. The hypothesis of absence of friction is not satisfied by any actual fluid; however, it is true that most technically important fluids, for instance air and water, have a very small friction coefficient and therefore behave in many cases almost like the ideal frictionless fluid. Many flow phenomena, in particular most cases of lift, can be treated satisfactorily, - that is, the calculations are in good agreement with the test results, -under the assumption of frictionless fluid. However, the calculations with frictionless flow show a very serious deficiency; namely, the fact, known as d'Alembert's paradox, that in frictionless flow each body has zero drag whereas in actual flow each body experiences a drag of greater or smaller magnitude. For a long time the theory has been unable to bridge this gap between the theory of frictionless flow and the experimental findings about actual flow. The cause of this fundamental discrepancy is the viscosity which is neglected in the theory of ideal fluid; however, in spite of its extraordinary smallness it is decisive for the course of the flow

Modeling of heavy-gas effects on airfoil flows

NASA Technical Reports Server (NTRS)

Drela, Mark

1992-01-01

Thermodynamic models were constructed for a calorically imperfect gas and for a non-ideal gas. These were incorporated into a quasi one dimensional flow solver to develop an understanding of the differences in flow behavior between the new models and the perfect gas model. The models were also incorporated into a two dimensional flow solver to investigate their effects on transonic airfoil flows. Specifically, the calculations simulated airfoil testing in a proposed high Reynolds number heavy gas test facility. The results indicate that the non-idealities caused significant differences in the flow field, but that matching of an appropriate non-dimensional parameter led to flows similar to those in air.

Reactive flow modeling of small scale detonation failure experiments for a baseline non-ideal explosive

NASA Astrophysics Data System (ADS)

Kittell, David E.; Cummock, Nick R.; Son, Steven F.

2016-08-01

Small scale characterization experiments using only 1-5 g of a baseline ammonium nitrate plus fuel oil (ANFO) explosive are discussed and simulated using an ignition and growth reactive flow model. There exists a strong need for the small scale characterization of non-ideal explosives in order to adequately survey the wide parameter space in sample composition, density, and microstructure of these materials. However, it is largely unknown in the scientific community whether any useful or meaningful result may be obtained from detonation failure, and whether a minimum sample size or level of confinement exists for the experiments. In this work, it is shown that the parameters of an ignition and growth rate law may be calibrated using the small scale data, which is obtained from a 35 GHz microwave interferometer. Calibration is feasible when the samples are heavily confined and overdriven; this conclusion is supported with detailed simulation output, including pressure and reaction contours inside the ANFO samples. The resulting shock wave velocity is most likely a combined chemical-mechanical response, and simulations of these experiments require an accurate unreacted equation of state (EOS) in addition to the calibrated reaction rate. Other experiments are proposed to gain further insight into the detonation failure data, as well as to help discriminate between the role of the EOS and reaction rate in predicting the measured outcome.

The Place of Ideals in Teaching.

ERIC Educational Resources Information Center

Hansen, David T.

This paper examines whether ideals and idealism have a role to play in teaching, identifying some ambiguities and problems associated with ideals and arguing that ideals figure importantly in teaching, but they are ideals of character or personhood as much as they are ideals of educational purpose. The first section focuses on the promise and…

Medical ethics and more: ideal theories, non-ideal theories and conscientious objection.

PubMed

Luna, Florencia

2015-01-01

Doing 'good medical ethics' requires acknowledgment that it is often practised in non-ideal circumstances! In this article I present the distinction between ideal theory (IT) and non-ideal theory (NIT). I show how IT may not be the best solution to tackle problems in non-ideal contexts. I sketch a NIT framework as a useful tool for bioethics and medical ethics and explain how NITs can contribute to policy design in non-ideal circumstances. Different NITs can coexist and be evaluated vis-à-vis the IT. Additionally, I address what an individual doctor ought to do in this non-ideal context with the view that knowledge of NITs can facilitate the decision-making process. NITs help conceptualise problems faced in the context of non-compliance and scarcity in a better and more realistic way. Deciding which policy is optimal in such contexts may influence physicians' decisions regarding their patients. Thus, this analysis-usually identified only with policy making-may also be relevant to medical ethics. Finally, I recognise that this is merely a first step in an unexplored but fundamental theoretical area and that more work needs to be done. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Restricted gene flow and local adaptation highlight the vulnerability of high-latitude reefs to rapid environmental change.

PubMed

Thomas, Luke; Kennington, W Jason; Evans, Richard D; Kendrick, Gary A; Stat, Michael

2017-06-01

Global climate change poses a serious threat to the future health of coral reef ecosystems. This calls for management strategies that are focused on maximizing the evolutionary potential of coral reefs. Fundamental to this is an accurate understanding of the spatial genetic structure in dominant reef-building coral species. In this study, we apply a genotyping-by-sequencing approach to investigate genome-wide patterns of genetic diversity, gene flow, and local adaptation in a reef-building coral, Pocillopora damicornis, across 10 degrees of latitude and a transition from temperate to tropical waters. We identified strong patterns of differentiation and reduced genetic diversity in high-latitude populations. In addition, genome-wide scans for selection identified a number of outlier loci putatively under directional selection with homology to proteins previously known to be involved in heat tolerance in corals and associated with processes such as photoprotection, protein degradation, and immunity. This study provides genomic evidence for both restricted gene flow and local adaptation in a widely distributed coral species, and highlights the potential vulnerability of leading-edge populations to rapid environmental change as they are locally adapted, reproductively isolated, and have reduced levels of genetic diversity. © 2017 John Wiley & Sons Ltd.

Developmental Idealism in China

PubMed Central

Thornton, Arland; Xie, Yu

2016-01-01

This paper examines the intersection of developmental idealism with China. It discusses how developmental idealism has been widely disseminated within China and has had enormous effects on public policy and programs, on social institutions, and on the lives of individuals and their families. This dissemination of developmental idealism to China began in the 19th century, when China met with several military defeats that led many in the country to question the place of China in the world. By the beginning of the 20th century, substantial numbers of Chinese had reacted to the country’s defeats by exploring developmental idealism as a route to independence, international respect, and prosperity. Then, with important but brief aberrations, the country began to implement many of the elements of developmental idealism, a movement that became especially important following the assumption of power by the Communist Party of China in 1949. This movement has played a substantial role in politics, in the economy, and in family life. The beliefs and values of developmental idealism have also been directly disseminated to the grassroots in China, where substantial majorities of Chinese citizens have assimilated them. These ideas are both known and endorsed by very large numbers in China today. PMID:28316833

Developmental Idealism in China.

PubMed

Thornton, Arland; Xie, Yu

2016-10-01

This paper examines the intersection of developmental idealism with China. It discusses how developmental idealism has been widely disseminated within China and has had enormous effects on public policy and programs, on social institutions, and on the lives of individuals and their families. This dissemination of developmental idealism to China began in the 19 th century, when China met with several military defeats that led many in the country to question the place of China in the world. By the beginning of the 20 th century, substantial numbers of Chinese had reacted to the country's defeats by exploring developmental idealism as a route to independence, international respect, and prosperity. Then, with important but brief aberrations, the country began to implement many of the elements of developmental idealism, a movement that became especially important following the assumption of power by the Communist Party of China in 1949. This movement has played a substantial role in politics, in the economy, and in family life. The beliefs and values of developmental idealism have also been directly disseminated to the grassroots in China, where substantial majorities of Chinese citizens have assimilated them. These ideas are both known and endorsed by very large numbers in China today.

Reactive flow modeling of small scale detonation failure experiments for a baseline non-ideal explosive

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kittell, David E.; Cummock, Nick R.; Son, Steven F.

2016-08-14

Small scale characterization experiments using only 1–5 g of a baseline ammonium nitrate plus fuel oil (ANFO) explosive are discussed and simulated using an ignition and growth reactive flow model. There exists a strong need for the small scale characterization of non-ideal explosives in order to adequately survey the wide parameter space in sample composition, density, and microstructure of these materials. However, it is largely unknown in the scientific community whether any useful or meaningful result may be obtained from detonation failure, and whether a minimum sample size or level of confinement exists for the experiments. In this work, itmore » is shown that the parameters of an ignition and growth rate law may be calibrated using the small scale data, which is obtained from a 35 GHz microwave interferometer. Calibration is feasible when the samples are heavily confined and overdriven; this conclusion is supported with detailed simulation output, including pressure and reaction contours inside the ANFO samples. The resulting shock wave velocity is most likely a combined chemical-mechanical response, and simulations of these experiments require an accurate unreacted equation of state (EOS) in addition to the calibrated reaction rate. Other experiments are proposed to gain further insight into the detonation failure data, as well as to help discriminate between the role of the EOS and reaction rate in predicting the measured outcome.« less

Dynamics of Vortex and Magnetic Lines in Ideal Hydrodynamics and MHD

NASA Astrophysics Data System (ADS)

Kuznetsov, E. A.; Ruban, V. P.

Vortex line and magnetic line representations are introduced for description of flows in ideal hydrodynamics and MHD, respectively. For incompressible fluids it is shown that the equations of motion for vorticity φ and magnetic field with the help of this transformation follow from the variational principle. By means of this representation it is possible to integrate the system of hydrodynamic type with the Hamiltonian H=|φ|dr. It is also demonstrated that these representations allow to remove from the noncanonical Poisson brackets, defined on the space of divergence-free vector fields, degeneracy connected with the vorticity frozenness for the Euler equation and with magnetic field frozenness for ideal MHD. For MHD a new Weber type transformation is found. It is shown how this transformation can be obtained from the two-fluid model when electrons and ions can be considered as two independent fluids. The Weber type transformation for ideal MHD gives the whole Lagrangian vector invariant. When this invariant is absent this transformation coincides with the Clebsch representation analog introduced in [1].

IDEAL Symposium on the East African Lakes

NASA Astrophysics Data System (ADS)

Johnson, T. C.; Kelts, K.; Lehman, J. T.; Wuest, A.

A vast array of interdisciplinary problems presented by the African Great Lakes were highlighted at the International Symposium on the Limnology, Climatology and Paleoclimatology of the East African Lakes, organized by the International Decade for the East African Lakes (IDEAL) February 17-21 in Jinja, Uganda. Approximately 125 scientists attended from North America, Europe, Africa, and New Zealand. Jinja is located on the northern shore of Lake Victoria at the head-waters of the Nile and is the site of the host institution for the symposium, the Uganda Freshwater Fisheries Research Organization (UFFRO). The conveners of the symposium were Tom Johnson of Duke University, George Kitaka of UNESCO-ROSTA, and Eric Odada of the University of Nairobi.

Multi-region relaxed Hall magnetohydrodynamics with flow

DOE PAGES

Lingam, Manasvi; Abdelhamid, Hamdi M.; Hudson, Stuart R.

2016-08-03

The recent formulations of multi-region relaxed magnetohydrodynamics (MRxMHD) have generalized the famous Woltjer-Taylor states by incorporating a collection of “ideal barriers” that prevent global relaxation and flow. In this paper, we generalize MRxMHD with flow to include Hall effects, and thereby obtain the partially relaxed counterparts of the famous double Beltrami states as a special subset. The physical and mathematical consequences arising from the introduction of the Hall term are also presented. We demonstrate that our results (in the ideal MHD limit) constitute an important subset of ideal MHD equilibria, and we compare our approach against other variational principles proposedmore » for deriving the partially relaxed states.« less

An exact solution for ideal dam-break floods on steep slopes

USGS Publications Warehouse

Ancey, C.; Iverson, R.M.; Rentschler, M.; Denlinger, R.P.

2008-01-01

The shallow-water equations are used to model the flow resulting from the sudden release of a finite volume of frictionless, incompressible fluid down a uniform slope of arbitrary inclination. The hodograph transformation and Riemann's method make it possible to transform the governing equations into a linear system and then deduce an exact analytical solution expressed in terms of readily evaluated integrals. Although the solution treats an idealized case never strictly realized in nature, it is uniquely well-suited for testing the robustness and accuracy of numerical models used to model shallow-water flows on steep slopes. Copyright 2008 by the American Geophysical Union.

Stability Results for Idealized Shear Flows on a Rectangular Periodic Domain

NASA Astrophysics Data System (ADS)

Dullin, Holger R.; Worthington, Joachim

2018-06-01

We present a new linearly stable solution of the Euler fluid flow on a torus. On a two-dimensional rectangular periodic domain [0,2π )× [0,2π / κ ) for κ \\in R^+, the Euler equations admit a family of stationary solutions given by the vorticity profiles Ω ^*(x)= Γ cos (p_1x_1+ κ p_2x_2). We show linear stability for such flows when p_2=0 and κ ≥ |p_1| (equivalently p_1=0 and κ {|p_2|}≤ {1}). The classical result due to Arnold is that for p_1 = 1, p_2 = 0 and κ ≥ 1 the stationary flow is nonlinearly stable via the energy-Casimir method. We show that for κ ≥ |p_1| ≥ 2, p_2 = 0 the flow is linearly stable, but one cannot expect a similar nonlinear stability result. Finally we prove nonlinear instability for all steady states satisfying p_1^2+κ ^2{p_2^2}>{3(κ ^2+1)}/4(7-4√{3)}. The modification and application of a structure-preserving Hamiltonian truncation is discussed for the anisotropic case κ ≠ 1. This leads to an explicit Lie-Poisson integrator for the approximate system, which is used to illustrate our analytical results.

Group Flow and Group Genius

ERIC Educational Resources Information Center

Sawyer, Keith

2015-01-01

Keith Sawyer views the spontaneous collaboration of group creativity and improvisation actions as "group flow," which organizations can use to function at optimum levels. Sawyer establishes ideal conditions for group flow: group goals, close listening, complete concentration, being in control, blending egos, equal participation, knowing…

Revisiting Maxwell’s accommodation coefficient: A study of nitrogen flow in a silica microtube across all flow regimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lei, Wenwen, E-mail: wlei@physics.usyd.edu.au; McKenzie, David R., E-mail: d.mckenzie@physics.usyd.edu.au

2014-12-15

Gas flows have been studied quantitatively for more than a hundred years and have relevance in modern fields such as the control of gas inputs to processes, the measurement of leak rates and the separation of gaseous species. Cha and McCoy have derived a convenient formula for the flow of an ideal gas applicable across a wide range of Knudsen numbers (Kn) that approaches the Navier–Stokes equations at small Kn and the Smoluchowski extension of the Knudsen flow equation at large Kn. Smoluchowski’s result relies on the Maxwell definition of the tangential momentum accommodation coefficient α, recently challenged by Aryamore » et al. We measure the flow rate of nitrogen gas in a smooth walled silica tube across a wide range of Knudsen numbers from 0.0048 to 12.4583. We find that the nitrogen flow obeys the Cha and McCoy equation with a large value of α, unlike carbon nanotubes which show flows consistent with a small value of α. Silica capillaries are therefore not atomically smooth. The flow at small Kn has α=0.91 and at large Kn has α close to one, consistent with the redefinition of accommodation coefficient by Arya et al., which also resolves a problem in the literature where there are many observations of α of less than one at small Kn and many equal to one at large Kn. Silica capillaries are an excellent choice for an accurate flow control system. - Highlights: • First experimental study on flow rate across all flow regimes in a well-defined microtube. • Extend Cha and McCoy theory for molecular flow regime. • Demonstrate the Maxwell accommodation coefficient is different in the slip and molecular flow regimes.« less

Propagation of exponential shock wave in an axisymmetric rotating non-ideal dusty gas

NASA Astrophysics Data System (ADS)

Nath, G.

2016-09-01

One-dimensional unsteady isothermal and adiabatic flow behind a strong exponential shock wave propagating in a rotational axisymmetric mixture of non-ideal gas and small solid particles, which has variable azimuthal and axial fluid velocities, is analyzed. The shock wave is driven out by a piston moving with time according to exponential law. The azimuthal and axial components of the fluid velocity in the ambient medium are assumed to be varying and obeying exponential laws. In the present work, small solid particles are considered as pseudo-fluid with the assumption that the equilibrium flow-conditions are maintained in the flow-field, and the viscous-stress and heat conduction of the mixture are negligible. Solutions are obtained in both the cases, when the flow between the shock and the piston is isothermal or adiabatic by taking into account the components of vorticity vector and compressibility. It is found that the assumption of zero temperature gradient brings a profound change in the density, axial component of vorticity vector and compressibility distributions as compared to that of the adiabatic case. To investigate the behavior of the flow variables and the influence on the shock wave propagation by the parameter of non-idealness of the gas overline{b} in the mixture as well as by the mass concentration of solid particles in the mixture Kp and by the ratio of the density of solid particles to the initial density of the gas G1 are worked out in detail. It is interesting to note that the shock strength increases with an increase in G1 ; whereas it decreases with an increase in overline{b} . Also, a comparison between the solutions in the cases of isothermal and adiabatic flows is made.

The ideal and the real in Klein and Milton: some observations on reading Paradise Lost.

PubMed

Steiner, John

2013-10-01

Extracts from Paradise Lost (Milton 1674) are presented to illustrate some ideas of mutual interest to poets and psychoanalysts. In particular, Milton portrays the distinction between the human and the divine in terms of God's perfection and omnipotence, in contrast to man's imperfections. Recognition of this difference can open a painful gap between the self and the ideal, leading to attempts to bridge it via omnipotence. Because we imbue our objects with omnipotence, a similar gap can arise between adult and child and between patient and analyst. Klein's description of the ideal good object highlights similar issues. Both Klein and Milton present the ideal as something important to internalize as a foundation for hope, trust, and belief in goodness, and both emphasize the ideal as something that can be aspired to but not omnipotently realized. Facing this distinction requires a capacity to relinquish and mourn the loss of the good object, as well as the loss of the omnipotence that made possession of it possible. © 2013 The Psychoanalytic Quarterly, Inc.

Resonance phenomena in a time-dependent, three-dimensional model of an idealized eddy

NASA Astrophysics Data System (ADS)

Rypina, I. I.; Pratt, L. J.; Wang, P.; Äe; -zgökmen, T. M.; Mezic, I.

2015-08-01

We analyze the geometry of Lagrangian motion and material barriers in a time-dependent, three-dimensional, Ekman-driven, rotating cylinder flow, which serves as an idealization for an isolated oceanic eddy and other overturning cells with cylindrical geometry in the ocean and atmosphere. The flow is forced at the top through an oscillating upper lid, and the response depends on the frequency and amplitude of lid oscillations. In particular, the Lagrangian geometry changes near the resonant tori of the unforced flow, whose frequencies are rationally related to the forcing frequencies. Multi-scale analytical expansions are used to simplify the flow in the vicinity of resonant trajectories and to investigate the resonant flow geometries. The resonance condition and scaling can be motivated by simple physical argument. The theoretically predicted flow geometries near resonant trajectories have then been confirmed through numerical simulations in a phenomenological model and in a full solution of the Navier-Stokes equations.

Negotiated media effects. Peer feedback modifies effects of media's thin-body ideal on adolescent girls.

PubMed

Veldhuis, Jolanda; Konijn, Elly A; Seidell, Jacob C

2014-02-01

The present study introduces a theoretical framework on negotiated media effects. Specifically, we argue that feedback of peers on thin-body ideal media images and individual dispositions guide effects on adolescent girls' psychosocial responses to media exposure. Therefore, we examined the thin-body ideal as portrayed in media and peers' feedback on such thin-ideal images in their combined effects on adolescent girls' body dissatisfaction, objectified body consciousness, and social comparison with media models. Hence, media models and peer comments were systematically combined as incorporated entities in YouTube-formats. Hypotheses were tested in a 3 (media models: extremely thin vs. thin vs. normal weight)×3 (peer comments: 6kg-underweight vs. 3kg-underweight vs. normal-weight)×2 (appearance schematicity: lower vs. higher) between-subjects design (N=216). Results showed that peer comments indicating that a media model was 'only 3kg-underweight' exerted most negative responses, particularly in girls who strongly process appearance relevant information. Peer feedback interacts with media models in guiding perceptions of what is considered an 'ideal' body shape. Results highlight the important role of peers as well as individual predispositions in view of understanding how thin-ideal media images may impact adolescent girls' body image concerns. Copyright © 2013 Elsevier Ltd. All rights reserved.

From the ideal market to the ideal clinic: constructing a normative standard of fairness for human subjects research.

PubMed

Phillips, Trisha

2011-02-01

Preventing exploitation in human subjects research requires a benchmark of fairness against which to judge the distribution of the benefits and burdens of a trial. This paper proposes the ideal market and its fair market price as a criterion of fairness. The ideal market approach is not new to discussions about exploitation, so this paper reviews Wertheimer's inchoate presentation of the ideal market as a principle of fairness, attempt of Emanuel and colleagues to apply the ideal market to human subjects research, and Ballantyne's criticisms of both the ideal market and the resulting benchmark of fairness. It argues that the criticism of this particular benchmark is on point, but the rejection of the ideal market is mistaken. After presenting a complete account of the ideal market, this paper proposes a new method for applying the ideal market to human subjects research and illustrates the proposal by considering a sample case.

Adaptive Numerical Dissipation Control in High Order Schemes for Multi-D Non-Ideal MHD

NASA Technical Reports Server (NTRS)

Yee, H. C.; Sjoegreen, B.

2005-01-01

The required type and amount of numerical dissipation/filter to accurately resolve all relevant multiscales of complex MHD unsteady high-speed shock/shear/turbulence/combustion problems are not only physical problem dependent, but also vary from one flow region to another. In addition, proper and efficient control of the divergence of the magnetic field (Div(B)) numerical error for high order shock-capturing methods poses extra requirements for the considered type of CPU intensive computations. The goal is to extend our adaptive numerical dissipation control in high order filter schemes and our new divergence-free methods for ideal MHD to non-ideal MHD that include viscosity and resistivity. The key idea consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and leave the rest of the region free from numerical dissipation contamination. These scheme-independent detectors are capable of distinguishing shocks/shears, flame sheets, turbulent fluctuations and spurious high-frequency oscillations. The detection algorithm is based on an artificial compression method (ACM) (for shocks/shears), and redundant multiresolution wavelets (WAV) (for the above types of flow feature). These filters also provide a natural and efficient way for the minimization of Div(B) numerical error.

Stability of ideal MHD configurations. I. Realizing the generality of the G operator

NASA Astrophysics Data System (ADS)

Keppens, R.; Demaerel, T.

2016-12-01

A field theoretical approach, applied to the time-reversible system described by the ideal magnetohydrodynamic (MHD) equations, exposes the full generality of MHD spectral theory. MHD spectral theory, which classified waves and instabilities of static or stationary, usually axisymmetric or translationally symmetric configurations, actually governs the stability of flowing, (self-)gravitating, single fluid descriptions of nonlinear, time-dependent idealized plasmas, and this at any time during their nonlinear evolution. At the core of this theory is a self-adjoint operator G , discovered by Frieman and Rotenberg [Rev. Mod. Phys. 32, 898 (1960)] in its application to stationary (i.e., time-independent) plasma states. This Frieman-Rotenberg operator dictates the acceleration identified by a Lagrangian displacement field ξ , which connects two ideal MHD states in four-dimensional space-time that share initial conditions for density, entropy, and magnetic field. The governing equation reads /d 2 ξ d t 2 = G [ ξ ] , as first noted by Cotsaftis and Newcomb [Nucl. Fusion, Suppl. Part 2, 447 and 451 (1962)]. The time derivatives at left are to be taken in the Lagrangian way, i.e., moving with the flow v. Physically realizable displacements must have finite energy, corresponding to being square integrable in the Hilbert space of displacements equipped with an inner product rule, for which the G operator is self-adjoint. The acceleration in the left-hand side features the Doppler-Coriolis operator v . ∇ , which is known to become an antisymmetric operator when restricting attention to stationary equilibria. Here, we present all derivations needed to get to these insights and connect results throughout the literature. A first illustration elucidates what can happen when self-gravity is incorporated and presents aspects that have been overlooked even in simple uniform media. Ideal MHD flows, as well as Euler flows, have essentially 6 + 1 wave types, where the 6 wave modes

Curiosity is Ready for Clay (Highlighted)

NASA Image and Video Library

2018-03-22

This mosaic taken by NASA's Mars Curiosity rover looks uphill at Mount Sharp, which Curiosity has been climbing. Highlighted in white is an area with clay-bearing rocks that scientists are eager to explore; it could shed additional light on the role of water in creating Mount Sharp. The mosaic was assembled from dozens of images taken by Curiosity's Mast Camera (Mastcam). It was taken on Sol 1931 back in January. Mount Sharp stands in the middle of Gale Crater, which is 96 miles (154 kilometers) in diameter. This mound, which Curiosity has been climbing since 2014, likely formed in the presence of water at various points of time in Mars ancient history. That makes it an ideal place to study how water influenced the habitability of Mars billions of years ago. The scene has been white-balanced so the colors of the rock materials resemble how they would appear under daytime lighting conditions on Earth. https://photojournal.jpl.nasa.gov/catalog/PIA22312

Ideals as Anchors for Relationship Experiences

PubMed Central

Frye, Margaret; Trinitapoli, Jenny

2016-01-01

Research on young-adult sexuality in sub-Saharan Africa typically conceptualizes sex as an individual-level risk behavior. We introduce a new approach that connects the conditions surrounding the initiation of sex with subsequent relationship well-being, examines relationships as sequences of interdependent events, and indexes relationship experiences to individually held ideals. New card-sort data from southern Malawi capture young women’s relationship experiences and their ideals in a sequential framework. Using optimal matching, we measure the distance between ideal and experienced relationship sequences to (1) assess the associations between ideological congruence and perceived relationship well-being, (2) compare this ideal-based approach to other experience-based alternatives, and (3) identify individual- and couple-level correlates of congruence between ideals and experiences in the romantic realm. We show that congruence between ideals and experiences conveys relationship well-being along four dimensions: expressions of love and support, robust communication habits, perceived biological safety, and perceived relationship stability. We further show that congruence is patterned by socioeconomic status and supported by shared ideals within romantic dyads. We argue that conceiving of ideals as anchors for how sexual experiences are manifest advances current understandings of romantic relationships, and we suggest that this approach has applications for other domains of life. PMID:27110031

Ideals and Category Typicality

ERIC Educational Resources Information Center

Kim, ShinWoo; Murphy, Gregory L.

2011-01-01

Barsalou (1985) argued that exemplars that serve category goals become more typical category members. Although this claim has received support, we investigated (a) whether categories have a single ideal, as negatively valenced categories (e.g., cigarette) often have conflicting goals, and (b) whether ideal items are in fact typical, as they often…

Ideal AFROC and FROC observers.

PubMed

Khurd, Parmeshwar; Liu, Bin; Gindi, Gene

2010-02-01

Detection of multiple lesions in images is a medically important task and free-response receiver operating characteristic (FROC) analyses and its variants, such as alternative FROC (AFROC) analyses, are commonly used to quantify performance in such tasks. However, ideal observers that optimize FROC or AFROC performance metrics have not yet been formulated in the general case. If available, such ideal observers may turn out to be valuable for imaging system optimization and in the design of computer aided diagnosis techniques for lesion detection in medical images. In this paper, we derive ideal AFROC and FROC observers. They are ideal in that they maximize, amongst all decision strategies, the area, or any partial area, under the associated AFROC or FROC curve. Calculation of observer performance for these ideal observers is computationally quite complex. We can reduce this complexity by considering forms of these observers that use false positive reports derived from signal-absent images only. We also consider a Bayes risk analysis for the multiple-signal detection task with an appropriate definition of costs. A general decision strategy that minimizes Bayes risk is derived. With particular cost constraints, this general decision strategy reduces to the decision strategy associated with the ideal AFROC or FROC observer.

Idealized debris flow in flume with bed driven by a conveyor belt

USGS Publications Warehouse

Ling, Chi-Hai; Chen, Cheng-lung

1989-01-01

The generalized viscoplastic fluid (GVF) model is used to derive the theoretical expressions of two-dimensional velocities and surface profile for debris flow established in a flume with bed driven by a conveyor belt. The rheological parameters of the GVF model are evaluated through the comparison of theoretical results with measured data. A slip velocity of the established (steady) nonuniform flow on the moving bed (i.e., the conveyor belt) is observed, and a relation between the slip velocity and the velocity gradient at the bed is derived. Two belts, one rough and the other smooth, were tested. The flow profile in the flume is found to be linear and dependent on the roughness of the belt, but not much on its speed.

Choosing a physician depends on how you want to feel: the role of ideal affect in health-related decision making.

PubMed

Sims, Tamara; Tsai, Jeanne L; Koopmann-Holm, Birgit; Thomas, Ewart A C; Goldstein, Mary K

2014-02-01

When given a choice, how do people decide which physician to select? Although significant research has demonstrated that how people actually feel (their "actual affect") influences their health care preferences, how people ideally want to feel (their "ideal affect") may play an even greater role. Specifically, we predicted that people trust physicians whose affective characteristics match their ideal affect, which leads people to prefer those physicians more. Consistent with this prediction, the more participants wanted to feel high arousal positive states on average (ideal HAP; e.g., excited), the more likely they were to select a HAP-focused physician. Similarly, the more people wanted to feel low arousal positive states on average (ideal LAP; e.g., calm), the more likely they were to select a LAP-focused physician. Also as predicted, these links were mediated by perceived physician trustworthiness. Notably, while participants' ideal affect predicted physician preference, actual affect (how much people actually felt HAP and LAP on average) did not. These findings suggest that people base serious decisions on how they want to feel, and highlight the importance of considering ideal affect in models of decision making preferences. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Can a numerically stable subgrid-scale model for turbulent flow computation be ideally accurate?: a preliminary theoretical study for the Gaussian filtered Navier-Stokes equations.

PubMed

Ida, Masato; Taniguchi, Nobuyuki

2003-09-01

This paper introduces a candidate for the origin of the numerical instabilities in large eddy simulation repeatedly observed in academic and practical industrial flow computations. Without resorting to any subgrid-scale modeling, but based on a simple assumption regarding the streamwise component of flow velocity, it is shown theoretically that in a channel-flow computation, the application of the Gaussian filtering to the incompressible Navier-Stokes equations yields a numerically unstable term, a cross-derivative term, which is similar to one appearing in the Gaussian filtered Vlasov equation derived by Klimas [J. Comput. Phys. 68, 202 (1987)] and also to one derived recently by Kobayashi and Shimomura [Phys. Fluids 15, L29 (2003)] from the tensor-diffusivity subgrid-scale term in a dynamic mixed model. The present result predicts that not only the numerical methods and the subgrid-scale models employed but also only the applied filtering process can be a seed of this numerical instability. An investigation concerning the relationship between the turbulent energy scattering and the unstable term shows that the instability of the term does not necessarily represent the backscatter of kinetic energy which has been considered a possible origin of numerical instabilities in large eddy simulation. The present findings raise the question whether a numerically stable subgrid-scale model can be ideally accurate.

Optimization of an idealized Y-Shaped Extracardiac Fontan Baffle

NASA Astrophysics Data System (ADS)

Yang, Weiguang; Feinstein, Jeffrey; Mohan Reddy, V.; Marsden, Alison

2008-11-01

Research has showed that vascular geometries can significantly impact hemodynamic performance, particularly in pediatric cardiology, where anatomy varies from one patient to another. In this study we optimize a newly proposed design for the Fontan procedure, a surgery used to treat single ventricle heart patients. The current Fontan procedure connects the inferior vena cava (IVC) to the pulmonary arteries (PA's) via a straight Gore-Tex tube, forming a T-shaped junction. In the Y-graft design, the IVC is connected to the left and right PAs by two branches. Initial studies on the Y-graft design showed an increase in efficiency and improvement in flow distribution compared to traditional designs in a single patient-specific model. We now optimize an idealized Y-graft model to refine the design prior to patient testing. A derivate-free optimization algorithm using Kriging surrogate functions and mesh adaptive direct search is coupled to a 3-D finite element Navier-Stokes solver. We will present optimization results for rest and exercise conditions and examine the influence of energy efficiency, wall shear stress, pulsatile flow, and flow distribution on the optimal design.

Measurement and Control of Electroosmotic Flow in Plastic Microchannels

NASA Astrophysics Data System (ADS)

Ross, David; Barker, Susan; Waddell, Emanuel; Johnson, Tim; Locascio, Laurie

2000-11-01

We have measured electroosmotic flow profiles in microchannels fabricated in a variety of commercially available plastics by imprinting using a silicon template and by UV laser ablation. It is possible to achieve nearly ideal plug flow profiles in straight imprinted channels made entirely of one material. In contrast, electroosmotic flow in imprinted channels constructed from two different materials and in channels fabricated using laser ablation show deviations from ideal plug flow resulting from non-uniformity of the surface charge density on the walls of the channels. We have also explored strategies for controlling electroosmotic flow through modification of the surface charge density. The techniques used to alter surface charge include the deposition of polyelectrolyte multilayers on channel surfaces and the use of combinations of imprinting and laser ablation in the fabrication of the channels. We will discuss the effectiveness of these strategies for controlling flow, sample dispersion, and mixing.

2D Slightly Compressible Ideal Flow in an Exterior Domain

NASA Astrophysics Data System (ADS)

Secchi, Paolo

2006-12-01

We consider the Euler equations of barotropic inviscid compressible fluids in the exterior domain. It is well known that, as the Mach number goes to zero, the compressible flows approximate the solution of the equations of motion of inviscid, incompressible fluids. In dimension 2 such limit solution exists on any arbitrary time interval, with no restriction on the size of the initial data. It is then natural to expect the same for the compressible solution, if the Mach number is sufficiently small. First we study the life span of smooth irrotational solutions, i.e. the largest time interval T(ɛ) of existence of classical solutions, when the initial data are a small perturbation of size ɛ from a constant state. Then, we study the nonlinear interaction between the irrotational part and the incompressible part of a general solution. This analysis yields the existence of smooth compressible flow on any arbitrary time interval and with no restriction on the size of the initial velocity, for any Mach number sufficiently small. Finally, the approach is applied to the study of the incompressible limit. For the proofs we use a combination of energy estimates and a decay estimate for the irrotational part.

Numerical simulation of vortical ideal fluid flow through curved channel

NASA Astrophysics Data System (ADS)

Moshkin, N. P.; Mounnamprang, P.

2003-04-01

A numerical algorithm to study the boundary-value problem in which the governing equations are the steady Euler equations and the vorticity is given on the inflow parts of the domain boundary is developed. The Euler equations are implemented in terms of the stream function and vorticity. An irregular physical domain is transformed into a rectangle in the computational domain and the Euler equations are rewritten with respect to a curvilinear co-ordinate system. The convergence of the finite-difference equations to the exact solution is shown experimentally for the test problems by comparing the computational results with the exact solutions on the sequence of grids. To find the pressure from the known vorticity and stream function, the Euler equations are utilized in the Gromeka-Lamb form. The numerical algorithm is illustrated with several examples of steady flow through a two-dimensional channel with curved walls. The analysis of calculations shows strong dependence of the pressure field on the vorticity given at the inflow parts of the boundary. Plots of the flow structure and isobars, for different geometries of channel and for different values of vorticity on entrance, are also presented.

Kirkwood–Buff integrals for ideal solutions

PubMed Central

Ploetz, Elizabeth A.; Bentenitis, Nikolaos; Smith, Paul E.

2010-01-01

The Kirkwood–Buff (KB) theory of solutions is a rigorous theory of solution mixtures which relates the molecular distributions between the solution components to the thermodynamic properties of the mixture. Ideal solutions represent a useful reference for understanding the properties of real solutions. Here, we derive expressions for the KB integrals, the central components of KB theory, in ideal solutions of any number of components corresponding to the three main concentration scales. The results are illustrated by use of molecular dynamics simulations for two binary solutions mixtures, benzene with toluene, and methanethiol with dimethylsulfide, which closely approach ideal behavior, and a binary mixture of benzene and methanol which is nonideal. Simulations of a quaternary mixture containing benzene, toluene, methanethiol, and dimethylsulfide suggest this system displays ideal behavior and that ideal behavior is not limited to mixtures containing a small number of components. PMID:20441282

Significance of settling model structures and parameter subsets in modelling WWTPs under wet-weather flow and filamentous bulking conditions.

PubMed

Ramin, Elham; Sin, Gürkan; Mikkelsen, Peter Steen; Plósz, Benedek Gy

2014-10-15

Current research focuses on predicting and mitigating the impacts of high hydraulic loadings on centralized wastewater treatment plants (WWTPs) under wet-weather conditions. The maximum permissible inflow to WWTPs depends not only on the settleability of activated sludge in secondary settling tanks (SSTs) but also on the hydraulic behaviour of SSTs. The present study investigates the impacts of ideal and non-ideal flow (dry and wet weather) and settling (good settling and bulking) boundary conditions on the sensitivity of WWTP model outputs to uncertainties intrinsic to the one-dimensional (1-D) SST model structures and parameters. We identify the critical sources of uncertainty in WWTP models through global sensitivity analysis (GSA) using the Benchmark simulation model No. 1 in combination with first- and second-order 1-D SST models. The results obtained illustrate that the contribution of settling parameters to the total variance of the key WWTP process outputs significantly depends on the influent flow and settling conditions. The magnitude of the impact is found to vary, depending on which type of 1-D SST model is used. Therefore, we identify and recommend potential parameter subsets for WWTP model calibration, and propose optimal choice of 1-D SST models under different flow and settling boundary conditions. Additionally, the hydraulic parameters in the second-order SST model are found significant under dynamic wet-weather flow conditions. These results highlight the importance of developing a more mechanistic based flow-dependent hydraulic sub-model in second-order 1-D SST models in the future. Copyright © 2014 Elsevier Ltd. All rights reserved.

Drive for muscularity and social physique anxiety mediate the perceived ideal physique muscle dysmorphia relationship.

PubMed

Thomas, Adam; Tod, David A; Edwards, Christian J; McGuigan, Michael R

2014-12-01

This study examined the mediating role of drive for muscularity and social physique anxiety (SPA) in the perceived muscular male ideal physique and muscle dysmorphia relationship in weight training men. Men (N = 146, mean ± SD; age, 22.8 ± 5.0 years; weight, 82.0 ± 11.1 kg; height, 1.80 ± 0.07 m; body mass index, 25.1 ± 3.0) who participated in weight training completed validated questionnaires measuring drive for muscularity, SPA, perceived muscular male ideal physique, global muscle dysmorphia, and several characteristics of muscle dysmorphia (exercise dependence, diet manipulation, concerns about size/symmetry, physique protection behavior, and supplementation). Perceived ideal physique was an independent predictor of muscle dysmorphia measures except physique protection (coefficients = 0.113-0.149, p ≤ 0.05). Perceived ideal physique also predicted muscle dysmorphia characteristics (except physique protection and diet) through the indirect drive for muscularity pathway (coefficients = 0.055-0.116, p ≤ 0.05). Perceived ideal physique also predicted size/symmetry concerns and physique protection through the indirect drive for muscularity and SPA pathway (coefficients = 0.080-0.025, p ≤ 0.05). These results extend current research by providing insights into the way correlates of muscle dysmorphia interact to predict the condition. The results also highlight signs (e.g., anxiety about muscularity) that strength and conditioning coaches can use to identify at-risk people who may benefit from being referred for psychological assistance.

Ideal regularization for learning kernels from labels.

PubMed

Pan, Binbin; Lai, Jianhuang; Shen, Lixin

2014-08-01

In this paper, we propose a new form of regularization that is able to utilize the label information of a data set for learning kernels. The proposed regularization, referred to as ideal regularization, is a linear function of the kernel matrix to be learned. The ideal regularization allows us to develop efficient algorithms to exploit labels. Three applications of the ideal regularization are considered. Firstly, we use the ideal regularization to incorporate the labels into a standard kernel, making the resulting kernel more appropriate for learning tasks. Next, we employ the ideal regularization to learn a data-dependent kernel matrix from an initial kernel matrix (which contains prior similarity information, geometric structures, and labels of the data). Finally, we incorporate the ideal regularization to some state-of-the-art kernel learning problems. With this regularization, these learning problems can be formulated as simpler ones which permit more efficient solvers. Empirical results show that the ideal regularization exploits the labels effectively and efficiently. Copyright © 2014 Elsevier Ltd. All rights reserved.

Intuitionistic fuzzy n-fold KU-ideal of KU-algebra

NASA Astrophysics Data System (ADS)

Mostafa, Samy M.; Kareem, Fatema F.

2018-05-01

In this paper, we apply the notion of intuitionistic fuzzy n-fold KU-ideal of KU-algebra. Some types of ideals such as intuitionistic fuzzy KU-ideal, intuitionistic fuzzy closed ideal and intuitionistic fuzzy n-fold KU-ideal are studied. Also, the relations between intuitionistic fuzzy n-fold KU-ideal and intuitionistic fuzzy KU-ideal are discussed. Furthermore, a few results of intuitionistic fuzzy n-fold KU-ideals of a KU-algebra under homomorphism are discussed.

Examples for Non-Ideal Solution Thermodynamics Study

ERIC Educational Resources Information Center

David, Carl W.

2004-01-01

A mathematical model of a non-ideal solution is presented, where it is shown how and where the non-ideality manifests itself in the standard thermodynamics tableau. Examples related to the non-ideal solution thermodynamics study are also included.

Flow Instability and Flow Control Scaling Laws

NASA Astrophysics Data System (ADS)

van Ness, Daniel; Corke, Thomas; Morris, Scott

2006-11-01

A flow instability that is receptive to perturbations is present in the tip clearance leakage flow over the tip of a turbine blade. This instability was investigated through the introduction of active flow control in the viscous flow field. Control was implemented in the form of a dielectric barrier discharge created by a weakly-ionized plasma actuation arrangement. The experimental setup consisted of a low-speed linear turbine cascade made up of an array of nine Pratt & Whitney ``PakB'' turbine blades. This idealized cascade configuration was used to examine the tip clearance leakage flow that exists within the low pressure turbine stage of a gas-turbine engine. The center blade of the cascade array had a variable tip clearance up to five percent chord. Reynolds numbers based on axial blade chord varied from 10^4 to 10^5. Multi-port pressure probe measurements, as well as Stereo Particle Image Velocimetry were used to document the dependence of the instability on the frequency and amplitude of flow control perturbations. Scaling laws based on the variation of blade tip clearance height and inflow conditions were investigated. These results permitted an improved understanding of the mechanism of flow instability.

Real-Gas Correction Factors for Hypersonic Flow Parameters in Helium

NASA Technical Reports Server (NTRS)

Erickson, Wayne D.

1960-01-01

The real-gas hypersonic flow parameters for helium have been calculated for stagnation temperatures from 0 F to 600 F and stagnation pressures up to 6,000 pounds per square inch absolute. The results of these calculations are presented in the form of simple correction factors which must be applied to the tabulated ideal-gas parameters. It has been shown that the deviations from the ideal-gas law which exist at high pressures may cause a corresponding significant error in the hypersonic flow parameters when calculated as an ideal gas. For example the ratio of the free-stream static to stagnation pressure as calculated from the thermodynamic properties of helium for a stagnation temperature of 80 F and pressure of 4,000 pounds per square inch absolute was found to be approximately 13 percent greater than that determined from the ideal-gas tabulation with a specific heat ratio of 5/3.

Invariant and partially-invariant solutions of the equations describing a non-stationary and isentropic flow for an ideal and compressible fluid in (3 + 1) dimensions

NASA Astrophysics Data System (ADS)

Grundland, A. M.; Lalague, L.

1996-04-01

This paper presents a new method of constructing, certain classes of solutions of a system of partial differential equations (PDEs) describing the non-stationary and isentropic flow for an ideal compressible fluid. A generalization of the symmetry reduction method to the case of partially-invariant solutions (PISs) has been formulated. We present a new algorithm for constructing PISs and discuss in detail the necessary conditions for the existence of non-reducible PISs. All these solutions have the defect structure 0305-4470/29/8/019/img1 and are computed from four-dimensional symmetric subalgebras. These theoretical considerations are illustrated by several examples. Finally, some new classes of invariant solutions obtained by the symmetry reduction method are included. These solutions represent central, conical, rational, spherical, cylindrical and non-scattering double waves.

Ideal Magnetic Dipole Scattering

NASA Astrophysics Data System (ADS)

Feng, Tianhua; Xu, Yi; Zhang, Wei; Miroshnichenko, Andrey E.

2017-04-01

We introduce the concept of tunable ideal magnetic dipole scattering, where a nonmagnetic nanoparticle scatters light as a pure magnetic dipole. High refractive index subwavelength nanoparticles usually support both electric and magnetic dipole responses. Thus, to achieve ideal magnetic dipole scattering one has to suppress the electric dipole response. Such a possibility was recently demonstrated for the so-called anapole mode, which is associated with zero electric dipole scattering. By spectrally overlapping the magnetic dipole resonance with the anapole mode, we achieve ideal magnetic dipole scattering in the far field with tunable strong scattering resonances in the near infrared spectrum. We demonstrate that such a condition can be realized at least for two subwavelength geometries. One of them is a core-shell nanosphere consisting of a Au core and silicon shell. It can be also achieved in other geometries, including nanodisks, which are compatible with current nanofabrication technology.

Divergence Free High Order Filter Methods for Multiscale Non-ideal MHD Flows

NASA Technical Reports Server (NTRS)

Yee, H. C.; Sjoegreen, Bjoern

2003-01-01

Low-dissipative high order filter finite difference methods for long time wave propagation of shock/turbulence/combustion compressible viscous MHD flows has been constructed. Several variants of the filter approach that cater to different flow types are proposed. These filters provide a natural and efficient way for the minimization of the divergence of the magnetic field (Delta . B) numerical error in the sense that no standard divergence cleaning is required. For certain 2-D MHD test problems, divergence free preservation of the magnetic fields of these filter schemes has been achieved.

Multiscale Simulation of Moist Global Atmospheric Flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grabowski, Wojciech W.; Smolarkiewicz, P. K.

The overarching goal of this award was to include phase changes of the water substance and accompanying latent heating and precipitation processes into the all-scale nonhydrostatic atmospheric dynamics EUlerian/LAGrangian (EULAG) model. The model includes fluid flow solver that is based on either an unabbreviated set of the governing equations (i.e., compressible dynamics) or a simplified set of equations without sound waves (i.e., sound-proof, either anelastic or pseudo-incompressible). The latter set has been used in small-scale dynamics for decades, but its application to the all-scale dynamics (from small-scale to planetary) has never been studied in practical implementations. The highlight of themore » project is the development of the moist implicit compressible model that can be run by applying time steps, as long as the anelastic model is limited only by the computational stability of the fluid flow and not by the speed of sound waves that limit the stability of explicit compressible models. Applying various versions of the EULAG model within the same numerical framework allows for an unprecedented comparison of solutions obtained with various sets of the governing equations and straightforward evaluation of the impact of various physical parameterizations on the model solutions. The main outcomes of this study are reported in three papers, two published and one currently under review. These papers include comparisons between model solutions for idealized moist problems across the range of scales from small to planetary. These tests include: moist thermals rising in the stable-stratified environment (following Grabowski and Clark, J. Atmos. Sci. 1991) and in the moist-neutral environment (after Bryan and Fritsch, Mon. Wea. Rev. 2002), moist flows over a mesoscale topography (as in Grabowski and Smolarkiewicz, Mon. Wea. Rev. 2002), deep convection in a sheared environment (following Weisman and Klemp, Mon. Wea. Rev. 1982), moist extension of the baroclinic

The Statistical Mechanics of Ideal Homogeneous Turbulence

NASA Technical Reports Server (NTRS)

Shebalin, John V.

2002-01-01

Plasmas, such as those found in the space environment or in plasma confinement devices, are often modeled as electrically conducting fluids. When fluids and plasmas are energetically stirred, regions of highly nonlinear, chaotic behavior known as turbulence arise. Understanding the fundamental nature of turbulence is a long-standing theoretical challenge. The present work describes a statistical theory concerning a certain class of nonlinear, finite dimensional, dynamical models of turbulence. These models arise when the partial differential equations describing incompressible, ideal (i.e., nondissipative) homogeneous fluid and magnetofluid (i.e., plasma) turbulence are Fourier transformed into a very large set of ordinary differential equations. These equations define a divergenceless flow in a high-dimensional phase space, which allows for the existence of a Liouville theorem, guaranteeing a distribution function based on constants of the motion (integral invariants). The novelty of these particular dynamical systems is that there are integral invariants other than the energy, and that some of these invariants behave like pseudoscalars under two of the discrete symmetry transformations of physics, parity, and charge conjugation. In this work the 'rugged invariants' of ideal homogeneous turbulence are shown to be the only significant scalar and pseudoscalar invariants. The discovery that pseudoscalar invariants cause symmetries of the original equations to be dynamically broken and induce a nonergodic structure on the associated phase space is the primary result presented here. Applicability of this result to dissipative turbulence is also discussed.

Fluctuation theorem for entropy production during effusion of an ideal gas with momentum transfer.

PubMed

Wood, Kevin; Van den Broeck, C; Kawai, R; Lindenberg, Katja

2007-06-01

We derive an exact expression for entropy production during effusion of an ideal gas driven by momentum transfer in addition to energy and particle flux. Following the treatment in Cleuren [Phys. Rev. E 74, 021117 (2006)], we construct a master equation formulation of the process and explicitly verify the thermodynamic fluctuation theorem, thereby directly exhibiting its extended applicability to particle flows and hence to hydrodynamic systems.

Compressible flow at high pressure with linear equation of state

NASA Astrophysics Data System (ADS)

Sirignano, William A.

2018-05-01

Compressible flow varies from ideal-gas behavior at high pressures where molecular interactions become important. Density is described through a cubic equation of state while enthalpy and sound speed are functions of both temperature and pressure, based on two parameters, A and B, related to intermolecular attraction and repulsion, respectively. Assuming small variations from ideal-gas behavior, a closed-form solution is obtained that is valid over a wide range of conditions. An expansion in these molecular-interaction parameters simplifies relations for flow variables, elucidating the role of molecular repulsion and attraction in variations from ideal-gas behavior. Real-gas modifications in density, enthalpy, and sound speed for a given pressure and temperature lead to variations in many basic compressible flow configurations. Sometimes, the variations can be substantial in quantitative or qualitative terms. The new approach is applied to choked-nozzle flow, isentropic flow, nonlinear-wave propagation, and flow across a shock wave, all for the real gas. Modifications are obtained for allowable mass-flow through a choked nozzle, nozzle thrust, sonic wave speed, Riemann invariants, Prandtl's shock relation, and the Rankine-Hugoniot relations. Forced acoustic oscillations can show substantial augmentation of pressure amplitudes when real-gas effects are taken into account. Shocks at higher temperatures and pressures can have larger pressure jumps with real-gas effects. Weak shocks decay to zero strength at sonic speed. The proposed framework can rely on any cubic equation of state and be applied to multicomponent flows or to more-complex flow configurations.

Solution of weakly compressible isothermal flow in landfill gas collection networks

NASA Astrophysics Data System (ADS)

Nec, Y.; Huculak, G.

2017-12-01

Pipe networks collecting gas in sanitary landfills operate under the regime of a weakly compressible isothermal flow of ideal gas. The effect of compressibility has been traditionally neglected in this application in favour of simplicity, thereby creating a conceptual incongruity between the flow equations and thermodynamic equation of state. Here the flow is solved by generalisation of the classic Darcy-Weisbach equation for an incompressible steady flow in a pipe to an ordinary differential equation, permitting continuous variation of density, viscosity and related fluid parameters, as well as head loss or gain due to gravity, in isothermal flow. The differential equation is solved analytically in the case of ideal gas for a single edge in the network. Thereafter the solution is used in an algorithm developed to construct the flow equations automatically for a network characterised by an incidence matrix, and determine pressure distribution, flow rates and all associated parameters therein.

High Order Filter Methods for the Non-ideal Compressible MHD Equations

NASA Technical Reports Server (NTRS)

Yee, H. C.; Sjoegreen, Bjoern

2003-01-01

The generalization of a class of low-dissipative high order filter finite difference methods for long time wave propagation of shock/turbulence/combustion compressible viscous gas dynamic flows to compressible MHD equations for structured curvilinear grids has been achieved. The new scheme is shown to provide a natural and efficient way for the minimization of the divergence of the magnetic field numerical error. Standard divergence cleaning is not required by the present filter approach. For certain non-ideal MHD test cases, divergence free preservation of the magnetic fields has been achieved.

How is the Ideal Gas Law Explanatory?

NASA Astrophysics Data System (ADS)

Woody, Andrea I.

2013-07-01

Using the ideal gas law as a comparative example, this essay reviews contemporary research in philosophy of science concerning scientific explanation. It outlines the inferential, causal, unification, and erotetic conceptions of explanation and discusses an alternative project, the functional perspective. In each case, the aim is to highlight insights from these investigations that are salient for pedagogical concerns. Perhaps most importantly, this essay argues that science teachers should be mindful of the normative and prescriptive components of explanatory discourse both in the classroom and in science more generally. Giving attention to this dimension of explanation not only will do justice to the nature of explanatory activity in science but also will support the development of robust reasoning skills in science students while helping them understand an important respect in which science is more than a straightforward collection of empirical facts, and consequently, science education involves more than simply learning them.

Improved Classification of Mammograms Following Idealized Training

PubMed Central

Hornsby, Adam N.; Love, Bradley C.

2014-01-01

People often make decisions by stochastically retrieving a small set of relevant memories. This limited retrieval implies that human performance can be improved by training on idealized category distributions (Giguère & Love, 2013). Here, we evaluate whether the benefits of idealized training extend to categorization of real-world stimuli, namely classifying mammograms as normal or tumorous. Participants in the idealized condition were trained exclusively on items that, according to a norming study, were relatively unambiguous. Participants in the actual condition were trained on a representative range of items. Despite being exclusively trained on easy items, idealized-condition participants were more accurate than those in the actual condition when tested on a range of item types. However, idealized participants experienced difficulties when test items were very dissimilar from training cases. The benefits of idealization, attributable to reducing noise arising from cognitive limitations in memory retrieval, suggest ways to improve real-world decision making. PMID:24955325

Improved Classification of Mammograms Following Idealized Training.

PubMed

Hornsby, Adam N; Love, Bradley C

2014-06-01

People often make decisions by stochastically retrieving a small set of relevant memories. This limited retrieval implies that human performance can be improved by training on idealized category distributions (Giguère & Love, 2013). Here, we evaluate whether the benefits of idealized training extend to categorization of real-world stimuli, namely classifying mammograms as normal or tumorous. Participants in the idealized condition were trained exclusively on items that, according to a norming study, were relatively unambiguous. Participants in the actual condition were trained on a representative range of items. Despite being exclusively trained on easy items, idealized-condition participants were more accurate than those in the actual condition when tested on a range of item types. However, idealized participants experienced difficulties when test items were very dissimilar from training cases. The benefits of idealization, attributable to reducing noise arising from cognitive limitations in memory retrieval, suggest ways to improve real-world decision making.

Ideal heat transfer conditions for tubular solar receivers with different design constraints

NASA Astrophysics Data System (ADS)

Kim, Jin-Soo; Potter, Daniel; Gardner, Wilson; Too, Yen Chean Soo; Padilla, Ricardo Vasquez

2017-06-01

The optimum heat transfer condition for a tubular type solar receiver was investigated for various receiver pipe size, heat transfer fluid, and design requirement and constraint(s). Heat transfer of a single plain receiver pipe exposed to concentrated solar energy was modelled along the flow path of the heat transfer fluid. Three different working fluids, molten salt, sodium, and supercritical carbon dioxide (sCO2) were considered in the case studies with different design conditions. The optimized ideal heat transfer condition was identified through fast iterative heat transfer calculations solving for all relevant radiation, conduction and convection heat transfers throughout the entire discretized tubular receiver. The ideal condition giving the best performance was obtained by finding the highest acceptable solar energy flux optimally distributed to meet different constraint(s), such as maximum allowable material temperature of receiver, maximum allowable film temperature of heat transfer fluid, and maximum allowable stress of receiver pipe material. The level of fluid side turbulence (represented by pressure drop in this study) was also optimized to give the highest net power production. As the outcome of the study gives information on the most ideal heat transfer condition, it can be used as a useful guideline for optimal design of a real receiver and solar field in a combined manner. The ideal heat transfer condition is especially important for high temperature tubular receivers (e.g. for supplying heat to high efficiency Brayton cycle turbines) where the system design and performance is tightly constrained by the receiver pipe material strength.

CITE 3 meteorological highlights

NASA Technical Reports Server (NTRS)

Shipham, Mark C.; Bachmeier, A. Scott; Anderson, Bruce E.

1993-01-01

Meteorological highlights from the third NASA Global Tropospheric Experiment Chemical Instrumentation Test and Evaluation (GTE/CITE 3) are presented. During August and September 1989, research flights were conducted from Wallops Island, Virginia, and Natal, Brazil, and included airborne sampling of air masses over adjacent regions of the Atlantic Ocean. Isentropic backward trajectory calculations, wind vector/streamline fields, rawinsonde data, and GOES and METEOSAT satellite imagery are utilized to examine the meteorological conditions for each flight and to determine the transport paths of the sampled air masses. Some aspects of the chemical signatures of the sampled air are also discussed. During the series of flights based at Wallops Island, Virginia, the flow into the experiment area was governed primarily by the position of the North Atlantic subtropical anticyclone. The large-scale tropospheric circulation switched from primarily a marine flow during flights 1-4, to a predominantly offshore mid-latitude continental flow during flights 5-10. During these later flights, the regional influences of large eastern U.S. cities along with vertical mixing by typical summertime convective activity strongly influenced the chemical characteristics of the sampled air. During the series of flights based at Natal, Brazil, the dominant synoptic feature was the South Atlantic subtropical anticyclone which generally transported air across the tropical Atlantic toward eastern Brazil. Pronounced subsidence and a well-defined trade wind inversion often characterized the lower and middle troposphere over the Natal region. Some high-altitude recirculation of air from South America was observed, as was cross-equatorial transport which had come from northern Africa. Biomass burning plumes were observed on segments of all of the flights, the source region being the central and southern savannah regions of Africa.

Parametric Study of Wall Shear Stress in Idealized Avian Airways

NASA Astrophysics Data System (ADS)

Farnsworth, Michael S.; Riede, Tobias; Thomson, Scott L.

2017-11-01

Because wall shear stress (WSS) affects cell response, WSS patterns in avian respiratory airways may be related to the origin of the syrinx and corresponding voice-producing tissue structures (e.g., membranes or vocal folds) in birds. To explore possible linkages between WSS patterns and the locations of avian voice-producing structures, a computational model of flow through an idealized portion of the avian respiratory airway, including trachea and primary bronchi sections, has been developed. The flow is governed by the Navier-Stokes equations, with velocity boundary conditions derived from pressure-flow data in an adult zebra finch during quiet respiration. Geometric parameters such as tracheal/bronchial diameter and length, as well as bronchial branching angle, are parametrically varied based on data for different avian species. Simulation results predict elevated WSS in the vicinity of the tracheobronchial juncture, the location at which voice-producing tissues are found in avian species. In this presentation, the model will be described and spatial distributions of WSS during inspiration and expiration will be presented and compared for different geometric configurations and respiration rates and waveforms. Funding for this project from the Gordon and Betty Moore Foundation (Grant 4498) is gratefully acknowledged.

Effect of fluid-colloid interactions on the mobility of a thermophoretic microswimmer in non-ideal fluids.

PubMed

Fedosov, Dmitry A; Sengupta, Ankush; Gompper, Gerhard

2015-09-07

Janus colloids propelled by light, e.g., thermophoretic particles, offer promising prospects as artificial microswimmers. However, their swimming behavior and its dependence on fluid properties and fluid-colloid interactions remain poorly understood. Here, we investigate the behavior of a thermophoretic Janus colloid in its own temperature gradient using numerical simulations. The dissipative particle dynamics method with energy conservation is used to investigate the behavior in non-ideal and ideal-gas like fluids for different fluid-colloid interactions, boundary conditions, and temperature-controlling strategies. The fluid-colloid interactions appear to have a strong effect on the colloid behavior, since they directly affect heat exchange between the colloid surface and the fluid. The simulation results show that a reduction of the heat exchange at the fluid-colloid interface leads to an enhancement of colloid's thermophoretic mobility. The colloid behavior is found to be different in non-ideal and ideal fluids, suggesting that fluid compressibility plays a significant role. The flow field around the colloid surface is found to be dominated by a source-dipole, in agreement with the recent theoretical and simulation predictions. Finally, different temperature-control strategies do not appear to have a strong effect on the colloid's swimming velocity.

An ideal free-kick

NASA Astrophysics Data System (ADS)

De Luca, R.; Faella, O.

2017-01-01

The kinematics of a free-kick is studied. As in projectile motion, the free-kick is ideal since we assume that a point-like ball moves in the absence of air resistance. We have experienced the fortunate conjuncture of a classical mechanics lecture taught right before an important football game. These types of sports events might trigger a great deal of attention from the classroom. The idealized problem is devised in such a way that students are eager to come to the end of the whole story.

Recharging Our Sense of Idealism: Concluding Thoughts

ERIC Educational Resources Information Center

D'Andrea, Michael; Dollarhide, Colette T.

2011-01-01

In this article, the authors aim to recharge one's sense of idealism. They argue that idealism is the Vitamin C that sustains one's commitment to implementing humanistic principles and social justice practices in the work of counselors and educators. The idealism that characterizes counselors and educators who are humanistic and social justice…

Which Way Is the Flow?

NASA Technical Reports Server (NTRS)

Kao, David

1999-01-01

The line integral convolution (LIC) technique has been known to be an effective tool for depicting flow patterns in a given vector field. There have been many extensions to make it run faster and reveal useful flow information such as velocity magnitude, motion, and direction. There are also extensions to unsteady flows and 3D vector fields. Surprisingly, none of these extensions automatically highlight flow features, which often represent the most important and interesting physical flow phenomena. In this sketch, a method for highlighting flow direction in LIC images is presented. The method gives an intuitive impression of flow direction in the given vector field and automatically reveals saddle points in the flow.

Performance analysis on free-piston Stirling cryocooler based on an idealized mathematical model

NASA Astrophysics Data System (ADS)

Guo, Y. X.; Chao, Y. J.; Gan, Z. H.; Li, S. Z.; Wang, B.

2017-12-01

Free-piston Stirling cryocoolers have extensive applications for its simplicity in structure and decrease in mass. However, the elimination of the motor and the crankshaft has made its thermodynamic characteristic different from that of Stirling cryocoolers with displacer driving mechanism. Therefore, an idealized mathematical model has been established, and with this model, an attempt has been made to analyse the thermodynamic characteristic and the performance of free-piston Stirling cryocooler. To certify this mathematical model, a comparison has been made between the model and a numerical model. This study reveals that due to the displacer damping force necessary for the production of cooling capacity, the free-piston Stirling cryocooler is inherently less efficient than Stirling cryocooler with displacer driving mechanism. Viscous flow resistance and incomplete heat transfer in the regenerator are the two major causes of the discrepancy between the results of the idealized mathematical model and the numerical model.

Genetic and environmental influences on thin-ideal internalization.

PubMed

Suisman, Jessica L; O'Connor, Shannon M; Sperry, Steffanie; Thompson, J Kevin; Keel, Pamela K; Burt, S Alexandra; Neale, Michael; Boker, Steven; Sisk, Cheryl; Klump, Kelly L

2012-12-01

Current research on the etiology of thin-ideal internalization focuses on psychosocial influences (e.g., media exposure). The possibility that genetic influences also account for variance in thin-ideal internalization has never been directly examined. This study used a twin design to estimate genetic effects on thin-ideal internalization and examine if environmental influences are primarily shared or nonshared in origin. Participants were 343 postpubertal female twins (ages: 12-22 years; M = 17.61) from the Michigan State University Twin Registry. Thin-ideal internalization was assessed using the Sociocultural Attitudes toward Appearance Questionnaire-3. Twin modeling suggested significant additive genetic and nonshared environmental influences on thin-ideal internalization. Shared environmental influences were small and non-significant. Although prior research focused on psychosocial factors, genetic influences on thin-ideal internalization were significant and moderate in magnitude. Research is needed to investigate possible interplay between genetic and nonshared environmental factors in the development of thin-ideal internalization. Copyright © 2012 Wiley Periodicals, Inc.

Hemodynamic Study of Flow Remodeling Stent Graft for the Treatment of Highly Angulated Abdominal Aortic Aneurysm

PubMed Central

Yeow, Siang Lin; Leo, Hwa Liang

2016-01-01

This study investigates the effect of a novel flow remodeling stent graft (FRSG) on the hemodynamic characteristics in highly angulated abdominal aortic aneurysm based on computational fluid dynamics (CFD) approach. An idealized aortic aneurysm with varying aortic neck angulations was constructed and CFD simulations were performed on nonstented models and stented models with FRSG. The influence of FRSG intervention on the hemodynamic performance is analyzed and compared in terms of flow patterns, wall shear stress (WSS), and pressure distribution in the aneurysm. The findings showed that aortic neck angulations significantly influence the velocity flow field in nonstented models, with larger angulations shifting the mainstream blood flow towards the center of the aorta. By introducing FRSG treatment into the aneurysm, erratic flow recirculation pattern in the aneurysm sac diminishes while the average velocity magnitude in the aneurysm sac was reduced in the range of 39% to 53%. FRSG intervention protects the aneurysm against the impacts of high velocity concentrated flow and decreases wall shear stress by more than 50%. The simulation results highlighted that FRSG may effectively treat aneurysm with high aortic neck angulations via the mechanism of promoting thrombus formation and subsequently led to the resorption of the aneurysm. PMID:27247612

Family Life and Developmental Idealism in Yazd, Iran

PubMed Central

Abbasi-Shavazi, Mohammad Jalal; Askari-Nodoushan, Abbas

2012-01-01

BACKGROUND This paper is motivated by the theory that developmental idealism has been disseminated globally and has become an international force for family and demographic change. Developmental idealism is a set of cultural beliefs and values about development and how development relates to family and demographic behavior. It holds that modern societies are causal forces producing modern families, that modern families help to produce modern societies, and that modern family change is to be expected. OBJECTIVE We examine the extent to which developmental idealism has been disseminated in Iran. We also investigate predictors of the dissemination of developmental idealism. METHODS We use survey data collected in 2007 from a sample of women in Yazd, a city in Iran. We examine the distribution of developmental idealism in the sample and the multivariate predictors of developmental idealism. RESULTS We find considerable support for the expectation that many elements of developmental idealism have been widely disseminated. Statistically significant majorities associate development with particular family attributes, believe that development causes change in families, believe that fertility reductions and age-at-marriage increases help foster development, and perceive family trends in Iran headed toward modernity. As predicted, parental education, respondent education, and income affect adherence to developmental idealism. CONCLUSIONS Developmental idealism has been widely disseminated in Yazd, Iran and is related to social and demographic factors in predicted ways. COMMENTS Although our data come from only one city, we expect that developmental idealism has been widely distributed in Iran, with important implications for family and demographic behavior. PMID:22942772

Ideal Cardiovascular Health and Incident Cardiovascular Events

PubMed Central

Ommerborn, Mark J.; Blackshear, Chad T.; Hickson, DeMarc A.; Griswold, Michael E.; Kwatra, Japneet; Djousse, Luc; Clark, Cheryl R.

2016-01-01

Introduction The epidemiology of American Heart Association ideal cardiovascular health (CVH) metrics has not been fully examined in African Americans. This study examines associations of CVH metrics with incident cardiovascular disease (CVD) in the Jackson Heart Study, a longitudinal cohort study of CVD in African Americans. Methods Jackson Heart Study participants without CVD (N=4,702) were followed prospectively between 2000 and 2011. Incidence rates and Cox proportional hazard ratios estimated risks for incident CVD (myocardial infarction, stroke, cardiac procedures, and CVD mortality) associated with seven CVH metrics by sex. Analyses were performed in 2015. Results Participants were followed for a median 8.3 years; none had ideal health on all seven CVH metrics. The prevalence of ideal health was low for nutrition, physical activity, BMI, and blood pressure metrics. The age-adjusted CVD incidence rate (IR) per 1,000 person years was highest for individuals with the least ideal health metrics: zero to one (IR=12.5, 95% CI=9.7, 16.1), two (IR=8.2, 95% CI=6.5, 10.4), three (IR=5.7, 95% CI=4.2, 7.6), and four or more (IR=3.4, 95% CI=2.0, 5.9). Adjusting for covariates, individuals with four or more ideal CVH metrics had lower risks of incident CVD compared with those with zero or one ideal CVH metric (hazard ratio, 0.29; 95% CI=0.17, 0.52; p<0.001). Conclusions African Americans with more ideal CVH metrics have lower risks of incident CVD. Comprehensive preventive behavioral and clinical supports should be intensified to improve CVD risk for African Americans with few ideal CVH metrics. PMID:27539974

Socialization and Selection Effects in the Association between Weight Conscious Peer Groups and Thin-Ideal Internalization: A Co-Twin Control Study

PubMed Central

Burt, S. Alexandra; O’Connor, Shannon; Thompson, J. Kevin; Klump, Kelly L.

2016-01-01

Affiliation with weight conscious peer groups is theorized to increase thin-ideal internalization through socialization processes. However, selection effects could contribute if genetic and/or environmental predispositions lead to affiliation with weight conscious peers. Co-twin control methodology was used to examine socialization and selection effects in 614 female twins (ages 8–15) from the Michigan State University Twin Registry (MSUTR). Thin-ideal internalization and peer group characteristics were assessed via self-report questionnaires. Results suggested the presence of both socialization and selection effects. In terms of socialization, twins who reported increased exposure to weight conscious peers relative to their co-twins had elevated thin-ideal internalization scores, regardless of zygosity. However, associations between weight conscious peers and thin-ideal internationalization within twin pairs were attenuated, suggesting that genetic and shared environmental selection effects also contribute. Findings significantly extend previous work by confirming the presence of socialization processes and highlighting selection processes to be examined in future longitudinal research. PMID:26859605

Magnetogasdynamics shock waves in a rotational axisymmetric non-ideal gas with increasing energy and conductive and radiative heat-fluxes

NASA Astrophysics Data System (ADS)

Nath, Gorakh

2016-07-01

Self-similar solutions are obtained for one-dimensional adiabatic flow behind a magnetogasdynamics cylindrical shock wave propagating in a rotational axisymmetric non ideal gas with increasing energy and conductive and radiative heat fluxes in presence of an azimuthal magnetic field. The fluid velocities and the azimuthal magnetic field in the ambient medium are assume to be varying and obeying power laws. In order to find the similarity solutions the angular velocity of the ambient medium is taken to be decreasing as the distance from the axis increases. The heat conduction is expressed in terms of Fourier's law and the radiation is considered to be the diffusion type for an optically thick grey gas model. The thermal conductivity and the absorption coefficient are assumed to vary with temperature and density. The effects of the presence of radiation and conduction, the non-idealness of the gas and the magnetic field on the shock propagation and the flow behind the shock are investigated.

The iFlow modelling framework v2.4: a modular idealized process-based model for flow and transport in estuaries

NASA Astrophysics Data System (ADS)

Dijkstra, Yoeri M.; Brouwer, Ronald L.; Schuttelaars, Henk M.; Schramkowski, George P.

2017-07-01

The iFlow modelling framework is a width-averaged model for the systematic analysis of the water motion and sediment transport processes in estuaries and tidal rivers. The distinctive solution method, a mathematical perturbation method, used in the model allows for identification of the effect of individual physical processes on the water motion and sediment transport and study of the sensitivity of these processes to model parameters. This distinction between processes provides a unique tool for interpreting and explaining hydrodynamic interactions and sediment trapping. iFlow also includes a large number of options to configure the model geometry and multiple choices of turbulence and salinity models. Additionally, the model contains auxiliary components, including one that facilitates easy and fast sensitivity studies. iFlow has a modular structure, which makes it easy to include, exclude or change individual model components, called modules. Depending on the required functionality for the application at hand, modules can be selected to construct anything from very simple quasi-linear models to rather complex models involving multiple non-linear interactions. This way, the model complexity can be adjusted to the application. Once the modules containing the required functionality are selected, the underlying model structure automatically ensures modules are called in the correct order. The model inserts iteration loops over groups of modules that are mutually dependent. iFlow also ensures a smooth coupling of modules using analytical and numerical solution methods. This way the model combines the speed and accuracy of analytical solutions with the versatility of numerical solution methods. In this paper we present the modular structure, solution method and two examples of the use of iFlow. In the examples we present two case studies, of the Yangtze and Scheldt rivers, demonstrating how iFlow facilitates the analysis of model results, the understanding of the

Predicting Film Genres with Implicit Ideals

PubMed Central

Olney, Andrew McGregor

2013-01-01

We present a new approach to defining film genre based on implicit ideals. When viewers rate the likability of a film, they indirectly express their ideal of what a film should be. Across six studies we investigate the category structure that emerges from likability ratings and the category structure that emerges from the features of film. We further compare these data-driven category structures with human annotated film genres. We conclude that film genres are structured more around ideals than around features of film. This finding lends experimental support to the notion that film genres are set of shifting, fuzzy, and highly contextualized psychological categories. PMID:23423823

Predicting film genres with implicit ideals.

PubMed

Olney, Andrew McGregor

2012-01-01

We present a new approach to defining film genre based on implicit ideals. When viewers rate the likability of a film, they indirectly express their ideal of what a film should be. Across six studies we investigate the category structure that emerges from likability ratings and the category structure that emerges from the features of film. We further compare these data-driven category structures with human annotated film genres. We conclude that film genres are structured more around ideals than around features of film. This finding lends experimental support to the notion that film genres are set of shifting, fuzzy, and highly contextualized psychological categories.

Overcoming spatio-temporal limitations using dynamically scaled in vitro PC-MRI - A flow field comparison to true-scale computer simulations of idealized, stented and patient-specific left main bifurcations.

PubMed

Beier, Susann; Ormiston, John; Webster, Mark; Cater, John; Norris, Stuart; Medrano-Gracia, Pau; Young, Alistair; Gilbert, Kathleen; Cowan, Brett

2016-08-01

The majority of patients with angina or heart failure have coronary artery disease. Left main bifurcations are particularly susceptible to pathological narrowing. Flow is a major factor of atheroma development, but limitations in imaging technology such as spatio-temporal resolution, signal-to-noise ratio (SNRv), and imaging artefacts prevent in vivo investigations. Computational fluid dynamics (CFD) modelling is a common numerical approach to study flow, but it requires a cautious and rigorous application for meaningful results. Left main bifurcation angles of 40°, 80° and 110° were found to represent the spread of an atlas based 100 computed tomography angiograms. Three left mains with these bifurcation angles were reconstructed with 1) idealized, 2) stented, and 3) patient-specific geometry. These were then approximately 7× scaled-up and 3D printing as large phantoms. Their flow was reproduced using a blood-analogous, dynamically scaled steady flow circuit, enabling in vitro phase-contrast magnetic resonance (PC-MRI) measurements. After threshold segmentation the image data was registered to true-scale CFD of the same coronary geometry using a coherent point drift algorithm, yielding a small covariance error (σ 2 <;5.8×10 -4 ). Natural-neighbour interpolation of the CFD data onto the PC-MRI grid enabled direct flow field comparison, showing very good agreement in magnitude (error 2-12%) and directional changes (r 2 0.87-0.91), and stent induced flow alternations were measureable for the first time. PC-MRI over-estimated velocities close to the wall, possibly due to partial voluming. Bifurcation shape determined the development of slow flow regions, which created lower SNRv regions and increased discrepancies. These can likely be minimised in future by testing different similarity parameters to reduce acquisition error and improve correlation further. It was demonstrated that in vitro large phantom acquisition correlates to true-scale coronary flow

Role of receptor occupancy assays by flow cytometry in drug development.

PubMed

Stewart, Jennifer J; Green, Cherie L; Jones, Nicholas; Liang, Meina; Xu, Yuanxin; Wilkins, Danice E C; Moulard, Maxime; Czechowska, Kamila; Lanham, David; McCloskey, Thomas W; Ferbas, John; van der Strate, Barry W A; Högerkorp, Carl-Magnus; Wyant, Timothy; Lackey, Alan; Litwin, Virginia

2016-03-01

The measurement of the binding of a biotherapeutic to its cellular target, receptor occupancy (RO), is increasingly important in development of biologically-based therapeutic agents. Receptor occupancy (RO) assays by flow cytometry describe the qualitative and/or quantitative assessment of the binding of a therapeutic agent to its cell surface target. Such RO assays can be as simple as measuring the number of cell surface receptors bound by an antireceptor therapeutic agent or can be designed to address more complicated scenarios such as internalization or shedding events once a receptor engages the administered therapeutic agent. Data generated from RO assays can also be used to model whether given doses of an experimental therapeutic agent and their administration schedules lead to predicted levels of receptor occupancy and whether the receptor is modulated (up or down) on cells engaged by the therapeutic agent. There are a variety of approaches that can be used when undertaking RO assays and with the ability to measure distinct subsets in heterogeneous populations, flow cytometry is ideally suited to RO measurements. This article highlights the importance of RO assays on the flow cytometric platform in the development of biotherapeutic agents. © 2016 The Authors Cytometry Part B: Clinical Cytometry Published by Wiley Periodicals, Inc.

Zonal flow as pattern formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parker, Jeffrey B.; Krommes, John A.

2013-10-15

Zonal flows are well known to arise spontaneously out of turbulence. We show that for statistically averaged equations of the stochastically forced generalized Hasegawa-Mima model, steady-state zonal flows, and inhomogeneous turbulence fit into the framework of pattern formation. There are many implications. First, the wavelength of the zonal flows is not unique. Indeed, in an idealized, infinite system, any wavelength within a certain continuous band corresponds to a solution. Second, of these wavelengths, only those within a smaller subband are linearly stable. Unstable wavelengths must evolve to reach a stable wavelength; this process manifests as merging jets.

Ideal Theory in Semigroups Based on Intersectional Soft Sets

PubMed Central

Song, Seok Zun; Jun, Young Bae

2014-01-01

The notions of int-soft semigroups and int-soft left (resp., right) ideals are introduced, and several properties are investigated. Using these notions and the notion of inclusive set, characterizations of subsemigroups and left (resp., right) ideals are considered. Using the notion of int-soft products, characterizations of int-soft semigroups and int-soft left (resp., right) ideals are discussed. We prove that the soft intersection of int-soft left (resp., right) ideals (resp., int-soft semigroups) is also int-soft left (resp., right) ideals (resp., int-soft semigroups). The concept of int-soft quasi-ideals is also introduced, and characterization of a regular semigroup is discussed. PMID:25101310

Young men's endorsement and pursuit of appearance ideals: The prospective role of appearance investment.

PubMed

Kling, Johanna; Rodgers, Rachel F; Frisén, Ann

2016-03-01

Appearance investment has been proposed as a risk factor for the development of body dissatisfaction. Despite this, few studies have explored men's investment in their appearance. The aim of the present study was therefore to examine appearance investment as a prospective predictor of young men's endorsement and pursuit of appearance ideals. A community sample of 187 young men participated in a study at ages 21 and 24. Hierarchical multiple regressions revealed that appearance investment, as hypothesized, was a prospective predictor of increases in leanness orientation, media-ideal internalization, and muscularity behaviors. However, appearance investment did not predict increases in muscularity dissatisfaction. The present findings highlight the importance of including appearance investment in sociocultural models of the development of men's body image, and suggest that appearance investment may be an important target variable to consider when designing body dissatisfaction prevention and intervention programs tailored to young men. Copyright © 2015 Elsevier Ltd. All rights reserved.

Boundary layers and global stability of laboratory quasi-Keplerian flow

NASA Astrophysics Data System (ADS)

Edlund, E. M.; Ji, H.

2013-11-01

Studies in the HTX device at PPPL, a modified Taylor-Couette experiment, have demonstrated a robust stability of astrophysically relevant, quasi-Keplerian flows. Independent rings on the axial boundary can be used to fine tune the rotation profile, allowing ideal Couette rotation to be achieved over nearly the entire radial gap. Fluctuation levels in these flows are observed to be at nearly the noise floor of the laser Doppler velocimetry (LDV) diagnostic, in agreement with prior studies under similar conditions. Deviations from optimal operating parameters illustrate the importance of centrifugally unstable boundary layers in Taylor-Couette devices of the classical configuration where the axial boundaries rotate with the outer cylinder. The global stability of nearly ideal-Couette flows, with implications for astrophysical systems, will be discussed in light of the global stability of these flows with respect to externally applied perturbations of large magnitude.

Investigation of mucus transport in an idealized lung airway model using multiphase CFD analysis

NASA Astrophysics Data System (ADS)

Rajendran, Rahul; Banerjee, Arindam

2015-11-01

Mucus, a Bingham fluid is transported in the pulmonary airways by consistent beating of the cilia and exhibits a wide range of physical properties in response to the core air flow and various pathological conditions. A better understanding of the interfacial instability is required as it plays a crucial role in gas transport, mixing, mucus clearance and drug delivery. In the current study, mucus is modelled as a Newtonian fluid and the two phase gas-liquid flow in the airways is investigated using an inhomogeneous Eulerian-Eulerian approach. The complex interface between the phases is tracked using the conventional VOF (Volume of Fluid) method. Results from our CFD simulations which are performed in idealized single and double bifurcation geometries will be presented and the influence of airflow rate, mucus layer thickness, mucus viscosity, airway geometry (branching & diameter) and surface tension on mucus flow behavior will be discussed. Mean mucus layer thickness, pressure drop due to momentum transfer & increased airway resistance, mucus transport speed and the flow morphology will be compared to existing experimental and theoretical data.

Supersonic beams at high particle densities: model description beyond the ideal gas approximation.

PubMed

Christen, Wolfgang; Rademann, Klaus; Even, Uzi

2010-10-28

Supersonic molecular beams constitute a very powerful technique in modern chemical physics. They offer several unique features such as a directed, collision-free flow of particles, very high luminosity, and an unsurpassed strong adiabatic cooling during the jet expansion. While it is generally recognized that their maximum flow velocity depends on the molecular weight and the temperature of the working fluid in the stagnation reservoir, not a lot is known on the effects of elevated particle densities. Frequently, the characteristics of supersonic beams are treated in diverse approximations of an ideal gas expansion. In these simplified model descriptions, the real gas character of fluid systems is ignored, although particle associations are responsible for fundamental processes such as the formation of clusters, both in the reservoir at increased densities and during the jet expansion. In this contribution, the various assumptions of ideal gas treatments of supersonic beams and their shortcomings are reviewed. It is shown in detail that a straightforward thermodynamic approach considering the initial and final enthalpy is capable of characterizing the terminal mean beam velocity, even at the liquid-vapor phase boundary and the critical point. Fluid properties are obtained using the most accurate equations of state available at present. This procedure provides the opportunity to naturally include the dramatic effects of nonideal gas behavior for a large variety of fluid systems. Besides the prediction of the terminal flow velocity, thermodynamic models of isentropic jet expansions permit an estimate of the upper limit of the beam temperature and the amount of condensation in the beam. These descriptions can even be extended to include spinodal decomposition processes, thus providing a generally applicable tool for investigating the two-phase region of high supersaturations not easily accessible otherwise.

Display format, highlight validity, and highlight method: Their effects on search performance

NASA Technical Reports Server (NTRS)

Donner, Kimberly A.; Mckay, Tim D.; Obrien, Kevin M.; Rudisill, Marianne

1991-01-01

Display format and highlight validity were shown to affect visual display search performance; however, these studies were conducted on small, artificial displays of alphanumeric stimuli. A study manipulating these variables was conducted using realistic, complex Space Shuttle information displays. A 2x2x3 within-subjects analysis of variance found that search times were faster for items in reformatted displays than for current displays. Responses to valid applications of highlight were significantly faster than responses to non or invalidly highlighted applications. The significant format by highlight validity interaction showed that there was little difference in response time to both current and reformatted displays when the highlight validity was applied; however, under the non or invalid highlight conditions, search times were faster with reformatted displays. A separate within-subject analysis of variance of display format, highlight validity, and several highlight methods did not reveal a main effect of highlight method. In addition, observed display search times were compared to search time predicted by Tullis' Display Analysis Program. Benefits of highlighting and reformatting displays to enhance search and the necessity to consider highlight validity and format characteristics in tandem for predicting search performance are discussed.

Maintaining ideal body weight counseling sessions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brammer, S.H.

The purpose of this program is to provide employees with the motivation, knowledge and skills necessary to maintain ideal body weight throughout life. The target audience for this program, which is conducted in an industrial setting, is the employee 40 years of age or younger who is at or near his/her ideal body weight.

Non-Ideal Compressible Fluid Dynamics: A Challenge for Theory

NASA Astrophysics Data System (ADS)

Kluwick, A.

2017-03-01

The possibility that compression as well as rarefaction shocks may form in single phase vapours was envisaged first by Bethe (1942). However calculations based on the Van der Waals equation of state indicated that the latter type of shock is possible only if the specific heat at constant volume cv divided by the universal gas constant R is larger than about 17.5 which he considered too large to be satisfied by real fluids. This conclusion was contested by Thompson (1971) who showed that the type of shock capable of forming in arbitrary fluids is determined by the sign of the thermodynamic quantity to which he referred to as fundamental derivative of gas dynamics. Here v, p, s and c denote the specific volume, the pressure, the entropy and the speed of sound. Thompson and co-workers also showed that the required condition for the existence of rarefaction shocks, that Γ may take on negative values, is indeed satisfied for a number of hydrocarbon and fluorocarbon vapours. This finding spawned a burst of theoretical studies elaborating on the unusual and often counterintuitive behaviour of shocks with rarefaction shocks present. These produced both results of theoretical character but also results suggesting the practical importance of Non-Ideal Compressible Fluid Dynamics in general. The present paper addresses some of the challenges encountered in connection with the theoretical treatment of the associated flow behaviour. Weakly nonlinear acoustic waves of finite amplitude serve as a starting point. Here mixed rather than strictly positive nonlinearity generates a wealth of phenomena not possible in perfect gases. Examples of steady flows where these non-classical effects play a decisive role (and which may be useful also for future experimental work) are quasi one-dimensional nozzle flows and transonic two-dimensional flows past corners. The study of viscous effects concentrates on laminar flows of boundary layer type. Here non-classical phenomena are caused by the

The Ideal Man and Woman According to University Students

ERIC Educational Resources Information Center

Weinstein, Lawrence; Laverghetta, Antonio V.; Peterson, Scott A.

2009-01-01

The present study determined if the ideal man has changed over the years and who and what the ideal woman is. We asked students at Cameron University to rate the importance of character traits that define the ideal man and woman. Subjects also provided examples of famous people exemplifying the ideal, good, average, and inferior man and woman. We…

Stereoscopic Particle Image Velocimetry Used to Study the Wake Patterns of an Ideal Anguilliform Swimming Motion

NASA Astrophysics Data System (ADS)

Taravella, Brandon; Potts, J. Baker; Stegmeir, Matthew

2014-11-01

The University of New Orleans recently acquired a self-contained stereoscopic particle image velocimetry system for use in their 125 ft long towing tank. This system is being used to study the wake flow behind an anguilliform swimming robot that swims with an ideal motion that is theorized not to produce any trailing vortices. The presentation will describe the particulars of the SPIV system along with details of installation of the SPIV system within the towing tank. The calibration routine will be discussed in detail and results of the free-flow runs will be discussed. Preliminary results from the anguilliform swimming motion will also be presented.

Interferograms, schlieren, and shadowgraphs constructed from real- and ideal-gas, two- and three-dimensional computed flowfields

NASA Technical Reports Server (NTRS)

Yates, Leslie A.

1993-01-01

The construction of interferograms, schlieren, and shadowgraphs from computed flowfield solutions permits one-to-one comparisons of computed and experimental results. A method of constructing these images from both ideal- and real-gas, two and three-dimensional computed flowfields is described. The computational grids can be structured or unstructured, and multiple grids are an option. Constructed images are shown for several types of computed flows including nozzle, wake, and reacting flows; comparisons to experimental images are also shown. In addition, th sensitivity of these images to errors in the flowfield solution is demonstrated, and the constructed images can be used to identify problem areas in the computations.

Interferograms, Schlieren, and Shadowgraphs Constructed from Real- and Ideal-Gas, Two- and Three-Dimensional Computed Flowfields

NASA Technical Reports Server (NTRS)

Yates, Leslie A.

1992-01-01

The construction of interferograms, schlieren, and shadowgraphs from computed flowfield solutions permits one-to-one comparisons of computed and experimental results. A method for constructing these images from both ideal- and real-gas, two- and three-dimensional computed flowfields is described. The computational grids can be structured or unstructured, and multiple grids are an option. Constructed images are shown for several types of computed flows including nozzle, wake, and reacting flows; comparisons to experimental images are also shown. In addition, the sensitivity of these images to errors in the flowfield solution is demonstrated, and the constructed images can be used to identify problem areas in the computations.

Reynolds number scaling of the influence of boundary layers on the global behavior of laboratory quasi-Keplerian flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edlund, E. M.; Ji, H.

2015-10-06

Here, we present fluid velocity measurements in a modified Taylor-Couette device operated in the quasi-Keplerian regime, where it is observed that nearly ideal flows exhibit self-similarity under scaling of the Reynolds number. In contrast, nonideal flows show progressive departure from ideal Couette as the Reynolds number is increased. We present a model that describes the observed departures from ideal Couette rotation as a function of the fluxes of angular momentum across the boundaries, capturing the dependence on Reynolds number and boundary conditions.

Reynolds number scaling of the influence of boundary layers on the global behavior of laboratory quasi-Keplerian flows.

PubMed

Edlund, E M; Ji, H

2015-10-01

We present fluid velocity measurements in a modified Taylor-Couette device operated in the quasi-Keplerian regime, where it is observed that nearly ideal flows exhibit self-similarity under scaling of the Reynolds number. In contrast, nonideal flows show progressive departure from ideal Couette as the Reynolds number is increased. We present a model that describes the observed departures from ideal Couette rotation as a function of the fluxes of angular momentum across the boundaries, capturing the dependence on Reynolds number and boundary conditions.

Swirling flow of a dissociated gas

NASA Technical Reports Server (NTRS)

Wolfram, W. R., Jr.; Walker, W. F.

1975-01-01

Most physical applications of the swirling flow, defined as a vortex superimposed on an axial flow in the nozzle, involve high temperatures and the possibility of real gas effects. The generalized one-dimensional swirling flow in a converging-diverging nozzle is analyzed for equilibrium and frozen dissociation using the ideal dissociating gas model. Numerical results are provided to illustrate the major effects and to compare with results obtained for a perfect gas with constant ratio of specific heats. It is found that, even in the case of real gases, perfect gas calculations can give a good estimate of the reduction in mass flow due to swirl.

The ideal oxygen/nitrous oxide fresh gas flow sequence with the Anesthesia Delivery Unit machine.

PubMed

Hendrickx, Jan F A; Cardinael, Sara; Carette, Rik; Lemmens, Hendrikus J M; De Wolf, Andre M

2007-06-01

To determine whether early reduction of oxygen and nitrous oxide fresh gas flow from 6 L/min to 0.7 L/min could be accomplished while maintaining end-expired nitrous oxide concentration > or =50% with an Anesthesia Delivery Unit anesthesia machine. Prospective, randomized clinical study. Large teaching hospital in Belgium. 53 ASA physical status I and II patients requiring general endotracheal anesthesia and controlled mechanical ventilation. Patients were randomly assigned to one of 4 groups depending on the duration of high oxygen/nitrous oxide fresh gas flow (two and 4 L/min, respectively) before lowering total fresh gas flow to 0.7 L/min (0.3 and 0.4 L/min oxygen and nitrous oxide, respectively): one, two, three, or 5 minutes (1-minute group, 2-minute group, 3-minute group, and 5-minute group), with n = 10, 12, 13, and 8, respectively. The course of the end-expired nitrous oxide concentration and bellows volume deficit at end-expiration was compared among the 4 groups during the first 30 minutes. At the end of the high-flow period the end-expired nitrous oxide concentration was 35.6 +/- 6.2%, 48.4 +/- 4.8%, 53.7 +/- 8.7%, and 57.3 +/- 1.6% in the 4 groups, respectively. Thereafter, the end-expired nitrous oxide concentration decreased to a nadir of 36.1 +/- 4.5%, 45.4 +/- 3.8%, 50.9 +/- 6.1%, and 55.4 +/- 2.8% after three, 4, 6, and 8 minutes after flows were lowered in the 1- to 5-minute groups, respectively. A decrease in bellows volume was observed in most patients, but was most pronounced in the 2-minute group. The bellows volume deficit gradually faded within 15 to 20 minutes in all 4 groups. A 3-minute high-flow period (oxygen and nitrous oxide fresh gas flow of 2 and 4 L/min, respectively) suffices to attain and maintain end-expired nitrous oxide concentration > or =50% and ensures an adequate bellows volume during the ensuing low-flow period.

Flow Meter Based on Freely Suspended Smectic Liquid Crystal Films

NASA Astrophysics Data System (ADS)

Green, Adam; Qi, Zhiyuan; Park, Cheol; Glaser, Matthew; Maclennan, Joseph; Clark, Noel

We present the realization of a idealized 2D hydrodynamic system coupled to air-flow, and show that freely suspended films (FSF) of smectic liquid crystals can be used as a novel flow-meter. Freely-suspended films of liquid crystals are one of the closest physical realizations of an idealized 2D fluid. The velocity of air-flow above a film suspended above a channel can be inferred by studying the velocity profile of the smectic film. This velocity profile can be measured using digital video microscopy to track the inclusions present in the moving film. The velocity profile is then fitted to the coupled 2D solutions of an embedded fluid in air, and the velocity of the air can then be extracted. This flow meter serves as a demonstration of a robust test-bed for further exploration of 2D hydrodynamics. This work was supported by NASA Grant No. NNX-13AQ81G, NSF MRSEC Grant No. DMR-0820579, and DMR-1420736.

Determination of pump flow rate during cardiopulmonary bypass in obese patients avoiding hemodilution.

PubMed

Santambrogio, Luisa; Leva, Cristian; Musazzi, Giorgio; Bruno, Piergiorgio; Vailati, Andrea; Zecchillo, Franco; Di Credico, Germano

2009-01-01

During cardiopulmonary bypass the pump flow is usually set on 2.4 L/min/m(2) of body surface area (BSA) to guarantee adequate tissue perfusion without differences for patient constitutional type. The present study attempts to evaluate the adequacy of pump flow rate in obese patients, considering the ideal weight instead of the real one, avoiding the overflow side effects and hemodilution. Obese patients with body mass index (BMI) > 30 presented for cardiac surgery were randomized in two groups: in one the cardiopulmonary bypass was led traditionally, in the other, pump flow rate was calculated on ideal BMI of 25. Demographics, preoperative tests, and monitoring data were registered. Mortality at hospital discharge and 30 days after were analyzed. The pump flow rate between the groups was different (4.46 vs. 4.87; p = 0.004); there were no differences in organ perfusion (SvO(2); diuresis) and mortality, but the study group presented fewer complications and blood transfusions. The BSA is widely used as the biometric unit to normalize physiologic parameters included pump flow rate, but it is disputable if this practice is correct also in obese patients. The study group, in which pump flow rate was set on ideal BSA, presented no difference in diuresis and mixed venous saturation but fewer complications and fewer perioperative blood transfusions.

Idealism and materialism in perception.

PubMed

Rose, David; Brown, Dora

2015-01-01

Koenderink (2014, Perception, 43, 1-6) has said most Perception readers are deluded, because they believe an 'All Seeing Eye' observes an objective reality. We trace the source of Koenderink's assertion to his metaphysical idealism, and point to two major weaknesses in his position-namely, its dualism and foundationalism. We counter with arguments from modern philosophy of science for the existence of an objective material reality, contrast Koenderink's enactivism to his idealism, and point to ways in which phenomenology and cognitive science are complementary and not mutually exclusive.

General Flow-Solver Code for Turbomachinery Applications

NASA Technical Reports Server (NTRS)

Dorney, Daniel; Sondak, Douglas

2006-01-01

Phantom is a computer code intended primarily for real-fluid turbomachinery problems. It is based on Corsair, an ideal-gas turbomachinery code, developed by the same authors, which evolved from the ROTOR codes from NASA Ames. Phantom is applicable to real and ideal fluids, both compressible and incompressible, flowing at subsonic, transonic, and supersonic speeds. It utilizes structured, overset, O- and H-type zonal grids to discretize flow fields and represent relative motions of components. Values on grid boundaries are updated at each time step by bilinear interpolation from adjacent grids. Inviscid fluxes are calculated to third-order spatial accuracy using Roe s scheme. Viscous fluxes are calculated using second-order-accurate central differences. The code is second-order accurate in time. Turbulence is represented by a modified Baldwin-Lomax algebraic model. The code offers two options for determining properties of fluids: One is based on equations of state, thermodynamic departure functions, and corresponding state principles. The other, which is more efficient, is based on splines generated from tables of properties of real fluids. Phantom currently contains fluid-property routines for water, hydrogen, oxygen, nitrogen, kerosene, methane, and carbon monoxide as well as ideal gases.

Gap Flows through Idealized Topography. Part I: Forcing by Large-Scale Winds in the Nonrotating Limit.

NASA Astrophysics Data System (ADS)

Gabersek, Sasa.; Durran, Dale R.

2004-12-01

Gap winds produced by a uniform airstream flowing over an isolated flat-top ridge cut by a straight narrow gap are investigated by numerical simulation. On the scale of the entire barrier, the proportion of the oncoming flow that passes through the gap is relatively independent of the nondimensional mountain height , even over that range of for which there is the previously documented transition from a “flow over the ridge” regime to a “flow around” regime.The kinematics and dynamics of the gap flow itself were investigated by examining mass and momentum budgets for control volumes at the entrance, central, and exit regions of the gap. These analyses suggest three basic behaviors: the linear regime (small ) in which there is essentially no enhancement of the gap flow; the mountain wave regime ( 1.5) in which vertical mass and momentum fluxes play a crucial role in creating very strong winds near the exit of the gap; and the upstream-blocking regime ( 5) in which lateral convergence generates the strongest winds near the entrance of the gap.Trajectory analysis of the flow in the strongest events, the mountain wave events, confirms the importance of net subsidence in creating high wind speeds. Neglect of vertical motion in applications of Bernoulli's equation to gap flows is shown to lead to unreasonable wind speed predictions whenever the temperature at the gap exit exceeds that at the gap entrance. The distribution of the Bernoulli function on an isentropic surface shows a correspondence between regions of high Bernoulli function and high wind speeds in the gap-exit jet similar to that previously documented for shallow-water flow.

Adaptive Numerical Dissipative Control in High Order Schemes for Multi-D Non-Ideal MHD

NASA Technical Reports Server (NTRS)

Yee, H. C.; Sjoegreen, B.

2004-01-01

The goal is to extend our adaptive numerical dissipation control in high order filter schemes and our new divergence-free methods for ideal MHD to non-ideal MHD that include viscosity and resistivity. The key idea consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and leave the rest of the region free of numerical dissipation contamination. These scheme-independent detectors are capable of distinguishing shocks/shears, flame sheets, turbulent fluctuations and spurious high-frequency oscillations. The detection algorithm is based on an artificial compression method (ACM) (for shocks/shears), and redundant multi-resolution wavelets (WAV) (for the above types of flow feature). These filter approaches also provide a natural and efficient way for the minimization of Div(B) numerical error. The filter scheme consists of spatially sixth order or higher non-dissipative spatial difference operators as the base scheme for the inviscid flux derivatives. If necessary, a small amount of high order linear dissipation is used to remove spurious high frequency oscillations. For example, an eighth-order centered linear dissipation (AD8) might be included in conjunction with a spatially sixth-order base scheme. The inviscid difference operator is applied twice for the viscous flux derivatives. After the completion of a full time step of the base scheme step, the solution is adaptively filtered by the product of a 'flow detector' and the 'nonlinear dissipative portion' of a high-resolution shock-capturing scheme. In addition, the scheme independent wavelet flow detector can be used in conjunction with spatially compact, spectral or spectral element type of base schemes. The ACM and wavelet filter schemes using the dissipative portion of a second-order shock-capturing scheme with sixth-order spatial central base scheme for both the inviscid and viscous MHD flux

Correcting for particle counting bias error in turbulent flow

NASA Technical Reports Server (NTRS)

Edwards, R. V.; Baratuci, W.

1985-01-01

An ideal seeding device is proposed generating particles that exactly follow the flow out are still a major source of error, i.e., with a particle counting bias wherein the probability of measuring velocity is a function of velocity. The error in the measured mean can be as much as 25%. Many schemes have been put forward to correct for this error, but there is not universal agreement as to the acceptability of any one method. In particular it is sometimes difficult to know if the assumptions required in the analysis are fulfilled by any particular flow measurement system. To check various correction mechanisms in an ideal way and to gain some insight into how to correct with the fewest initial assumptions, a computer simulation is constructed to simulate laser anemometer measurements in a turbulent flow. That simulator and the results of its use are discussed.

Medical learning curves and the Kantian ideal.

PubMed

Le Morvan, P; Stock, B

2005-09-01

A hitherto unexamined problem for the "Kantian ideal" that one should always treat patients as ends in themselves, and never only as a means to other ends, is explored in this paper. The problem consists of a prima facie conflict between this Kantian ideal and the reality of medical practice. This conflict arises because, at least presently, medical practitioners can only acquire certain skills and abilities by practising on live, human patients, and given the inevitability and ubiquity of learning curves, this learning requires some patients to be treated only as a means to this end. A number of ways of attempting to establish the compatibility of the Kantian Ideal with the reality of medical practice are considered. Each attempt is found to be unsuccessful. Accordingly, until a way is found to reconcile them, we conclude that the Kantian ideal is inconsistent with the reality of medical practice.

Medical learning curves and the Kantian ideal

PubMed Central

Le Morvan, P; Stock, B

2005-01-01

A hitherto unexamined problem for the "Kantian ideal" that one should always treat patients as ends in themselves, and never only as a means to other ends, is explored in this paper. The problem consists of a prima facie conflict between this Kantian ideal and the reality of medical practice. This conflict arises because, at least presently, medical practitioners can only acquire certain skills and abilities by practising on live, human patients, and given the inevitability and ubiquity of learning curves, this learning requires some patients to be treated only as a means to this end. A number of ways of attempting to establish the compatibility of the Kantian Ideal with the reality of medical practice are considered. Each attempt is found to be unsuccessful. Accordingly, until a way is found to reconcile them, we conclude that the Kantian ideal is inconsistent with the reality of medical practice. PMID:16131552

[The style of leadership idealized by nurses].

PubMed

Higa, Elza de Fátima Ribeiro; Trevizan, Maria Auxiliadora

2005-01-01

This study focuses on nursing leadership on the basis of Grid theories. According to the authors, these theories are an alternative that allows for leadership development in nursing. The research aimed to identify and analyze the style of leadership idealized by nurses, according to their own view, and to compare the styles of leadership idealized by nurses between the two research institutions. Study subjects were 13 nurses. The results show that nurses at both institutions equally mention they idealize style 9.9, followed by 5.5 and 1.9, with a tendency to reject styles 9.1 and 1.1.

Concepts of Ideal and Nonideal Explosives.

DTIC Science & Technology

1981-12-01

Akst and J. Hershkowitz, "Explosive Performance Modification by Cosolidifaction of Ammonium Nitrate with Fuels ," Technical Report 4987, Picatinny...explosives Equations of state Diameter effect Ammonium nitrate 20. ASSrRACr (ca’mes r w re t N netwezy ad identity by block number) The purpose of...this report is to stimulate discussion on the nonideality of ammonium nitrate and its composite explosives. The concept of ideal and non- ideal

Flow velocity measurements with stimulated Rayleigh-Brillouin-gain spectroscopy

NASA Technical Reports Server (NTRS)

Herring, G. C.; Moosmueller, H.; Lee, S. A.; She, C. Y.

1983-01-01

Using stimulated Rayleigh-Brillouin-gain spectroscopy, velocity measurements in an atmospheric-pressure subsonic nitrogen flow with 10 percent uncertainty have been conducted. It is shown that the accuracy of the velocity measurements increases with gas pressure, making this spectroscopic technique ideal for measuring velocity and other parameters of high-pressure (greater than 1-atm) atomic or molecular flows.

The realities of idealism.

PubMed

Roslyn, J J

1993-04-01

I started out asking the question can we achieve our goals and are our goals realistic in the 1990s? I believe that we can achieve anything that we set our minds to. Our goals of providing quality care to our patients, performing research, teaching the next generation, and having an impact on our local environment are worth pursuing. However, the rules have changed and the status quo is simply not good enough. If we are to survive, we must be prepared for the future. You have the ability to change and the power to control the future. You are the future. Seize the opportunity and get involved. Become knowledgeable about health care economics, become involved with the political process, and position yourselves so that you can be a part of the solution to our health care system's woes. Don't allow the moment to pass. Don't be afraid of the realities of today, and don't forget your ideals and principles. Confront today's challenges with the same determination that academic surgeons through the years have confronted the unknown mysteries of disease. Let me conclude by trying to synthesize my remarks in five generic recommendations: 1. We need to go forward in the research area by developing multidisciplinary programs that involve basic science. These programs can be used to highlight our clinical areas and expertise. In this manner, both areas will be benefitted. 2. We need to educate the public and the government about the virtues of research and the importance of maintaining academic surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Parametric Characterization of Flow Inside Cererbal Aneurysms Treated with Flow-Diverting Stents

NASA Astrophysics Data System (ADS)

Barbour, Michael; Levitt, Michael; Geindreau, Christian; Johnson, Luke; Chivukula, Keshav; Aliseda, Alberto

2017-11-01

Cerebral aneurysms are often treated with a flow-diverting stent (FDS) to reduce blood flow into the aneurysm sac, promoting the development of a stable thrombus. Successful treatment is highly dependent on the degree of flow reduction and the altered hemodynamics inside the aneurysm sac following treatment. Establishing a causal connection between hemodynamic metrics of FDS-treated CAs and long-term clinical outcomes requires a rigorous parametric characterization of this flow environment. We use 3D particle image velocimetry (PIV) to measure the flow inside idealized aneurysm models treated with FDS. Physiologically realistic Reynolds numbers and increasing levels of parent vessel curvature are analyzed to understand the effect of inertia on flow development. The flow velocity into the aneurysm and the topology of the flow inside the sac is shown to be highly dependent on parent vessel Dean number (De). The role of flow pulsatility is then added to the study via time-dependent waveforms. Velocity measurements at 2 values of parent vessel Womersley number (Wo) allow us to parameterize flow inside of CAs treated with FDS as a function of De, Re and Wo, improving the fundamental understanding of how FDS alter CA hemodynamics and aiding in the development of new treatments.

Ideal strength of bcc molybdenum and niobium

NASA Astrophysics Data System (ADS)

Luo, Weidong; Roundy, D.; Cohen, Marvin L.; Morris, J. W.

2002-09-01

The behavior of bcc Mo and Nb under large strain was investigated using the ab initio pseudopotential density-functional method. We calculated the ideal shear strength for the {211}<111> and {011}<111> slip systems and the ideal tensile strength in the <100> direction, which are believed to provide the minimum shear and tensile strengths. As either material is sheared in either of the two systems, it evolves toward a stress-free tetragonal structure that defines a saddle point in the strain-energy surface. The inflection point on the path to this tetragonal ``saddle-point'' structure sets the ideal shear strength. When either material is strained in tension along <100>, it initially follows the tetragonal, ``Bain,'' path toward a stress-free fcc structure. However, before the strained crystal reaches fcc, its symmetry changes from tetragonal to orthorhombic; on continued strain it evolves toward the same tetragonal saddle point that is reached in shear. In Mo, the symmetry break occurs after the point of maximum tensile stress has been passed, so the ideal strength is associated with the fcc extremum as in W. However, a Nb crystal strained in <100> becomes orthorhombic at tensile stress below the ideal strength. The ideal tensile strength of Nb is associated with the tetragonal saddle point and is caused by failure in shear rather than tension. In dimensionless form, the ideal shear and tensile strengths of Mo (τ*=τm/G111=0.12, σ*=σm/E100=0.078) are essentially identical to those previously calculated for W. Nb is anomalous. Its dimensionless shear strength is unusually high, τ*=0.15, even though the saddle-point structure that causes it is similar to that in Mo and W, while its dimensionless tensile strength, σ*=0.079, is almost the same as that of Mo and W, even though the saddle-point structure is quite different.

Boundary Layer Theory. Part 1; Laminar Flows

NASA Technical Reports Server (NTRS)

Schlichting, H.

1949-01-01

The purpose of this presentation is to give you a survey of a field of aerodynamics which has for a number of years been attracting an ever growing interest. The subject is the theory of flows with friction, and, within that field, particularly the theory of friction layers, or boundary layers. As you know, a great many considerations of aerodynamics are based on the so-called ideal fluid, that is, the frictionless incompressible fluid. By neglect of compressibility and friction the extensive mathematical theory of the ideal fluid (potential theory) has been made possible.

Ideal and Nonideal Reasoning in Educational Theory

ERIC Educational Resources Information Center

Jaggar, Alison M.

2015-01-01

The terms "ideal theory" and "nonideal theory" are used in contemporary Anglophone political philosophy to identify alternative methodological approaches for justifying normative claims. Each term is used in multiple ways. In this article Alison M. Jaggar disentangles several versions of ideal and nonideal theory with a view to…

Idealized cultural beliefs about gender: implications for mental health.

PubMed

Mahalingam, Ramaswami; Jackson, Benita

2007-12-01

In this paper, we examined the relationship between culture-specific ideals (chastity, masculinity, caste beliefs) and self-esteem, shame and depression using an idealized cultural model proposed by Mahalingam (2006, In: Mahalingam R (ed) Cultural psychology of immigrants. Lawrence Erlbaum, Mahwah, NJ, pp 1-14). Participants were from communities with a history of extreme male-biased sex ratios in Tamilnadu, India (N = 785). We hypothesized a dual-process model of self-appraisals suggesting that achieving idealized cultural identities would increase both self-esteem and shame, with the latter leading to depression, even after controlling for key covariates. We tested this using structural equation modeling. The proposed idealized cultural identities model had an excellent fit (CFI = 0.99); the effect of idealized identities on self-esteem, shame and depression differed by gender. Idealized beliefs about gender relate to psychological well-being in gender specific ways in extreme son preference communities. We discuss implications of these findings for future research and community-based interventions.

As a Matter of Force—Systematic Biases in Idealized Turbulence Simulations

NASA Astrophysics Data System (ADS)

Grete, Philipp; O’Shea, Brian W.; Beckwith, Kris

2018-05-01

Many astrophysical systems encompass very large dynamical ranges in space and time, which are not accessible by direct numerical simulations. Thus, idealized subvolumes are often used to study small-scale effects including the dynamics of turbulence. These turbulent boxes require an artificial driving in order to mimic energy injection from large-scale processes. In this Letter, we show and quantify how the autocorrelation time of the driving and its normalization systematically change the properties of an isothermal compressible magnetohydrodynamic flow in the sub- and supersonic regime and affect astrophysical observations such as Faraday rotation. For example, we find that δ-in-time forcing with a constant energy injection leads to a steeper slope in kinetic energy spectrum and less-efficient small-scale dynamo action. In general, we show that shorter autocorrelation times require more power in the acceleration field, which results in more power in compressive modes that weaken the anticorrelation between density and magnetic field strength. Thus, derived observables, such as the line-of-sight (LOS) magnetic field from rotation measures, are systematically biased by the driving mechanism. We argue that δ-in-time forcing is unrealistic and numerically unresolved, and conclude that special care needs to be taken in interpreting observational results based on the use of idealized simulations.

Magnetogasdynamic spherical shock wave in a non-ideal gas under gravitational field with conductive and radiative heat fluxes

NASA Astrophysics Data System (ADS)

Nath, G.; Vishwakarma, J. P.

2016-11-01

Similarity solutions are obtained for the flow behind a spherical shock wave in a non-ideal gas under gravitational field with conductive and radiative heat fluxes, in the presence of a spatially decreasing azimuthal magnetic field. The shock wave is driven by a piston moving with time according to power law. The radiation is considered to be of the diffusion type for an optically thick grey gas model and the heat conduction is expressed in terms of Fourier's law for heat conduction. Similarity solutions exist only when the surrounding medium is of constant density. The gas is assumed to have infinite electrical conductivity and to obey a simplified van der Waals equation of state. It is shown that an increase of the gravitational parameter or the Alfven-Mach number or the parameter of the non-idealness of the gas decreases the compressibility of the gas in the flow-field behind the shock, and hence there is a decrease in the shock strength. The pressure and density vanish at the inner surface (piston) and hence a vacuum is formed at the center of symmetry. The shock waves in conducting non-ideal gas under gravitational field with conductive and radiative heat fluxes can be important for description of shocks in supernova explosions, in the study of a flare produced shock in the solar wind, central part of star burst galaxies, nuclear explosion etc. The solutions obtained can be used to interpret measurements carried out by space craft in the solar wind and in neighborhood of the Earth's magnetosphere.

User Guide for Compressible Flow Toolbox Version 2.1 for Use With MATLAB(Registered Trademark); Version 7

NASA Technical Reports Server (NTRS)

Melcher, Kevin J.

2006-01-01

This report provides a user guide for the Compressible Flow Toolbox, a collection of algorithms that solve almost 300 linear and nonlinear classical compressible flow relations. The algorithms, implemented in the popular MATLAB programming language, are useful for analysis of one-dimensional steady flow with constant entropy, friction, heat transfer, or shock discontinuities. The solutions do not include any gas dissociative effects. The toolbox also contains functions for comparing and validating the equation-solving algorithms against solutions previously published in the open literature. The classical equations solved by the Compressible Flow Toolbox are: isentropic-flow equations, Fanno flow equations (pertaining to flow of an ideal gas in a pipe with friction), Rayleigh flow equations (pertaining to frictionless flow of an ideal gas, with heat transfer, in a pipe of constant cross section.), normal-shock equations, oblique-shock equations, and Prandtl-Meyer expansion equations. At the time this report was published, the Compressible Flow Toolbox was available without cost from the NASA Software Repository.

Silver and gold nanoparticle separation using asymmetrical flow-field flow fractionation: Influence of run conditions and of particle and membrane charges.

PubMed

Meisterjahn, Boris; Wagner, Stephan; von der Kammer, Frank; Hennecke, Dieter; Hofmann, Thilo

2016-04-01

Flow-Field Flow Fractionation (Flow-FFF), coupled with online detection systems is one of the most promising tools available for the separation and quantification of engineered nanoparticles (ENPs) in complex matrices. To correctly relate the retention of nanoparticles in the Flow-FFF-channel to the particle size, ideal separation conditions must be met. This requires optimization of the parameters that influence the separation behavior. The aim of this study was therefore to systematically investigate and evaluate the influence of parameters such as the carrier liquid, the cross flow, and the membrane material, on the separation behavior of two metallic ENPs. For this purpose the retention, recovery, and separation efficiency of sterically stabilized silver nanoparticles (AgNPs) and electrostatically stabilized gold nanoparticles (AuNPs), which represent two materials widely used in investigations on environmental fate and ecotoxicology, were investigated against a parameter matrix of three different cross-flow densities, four representative carrier solutions, and two membrane materials. The use of a complex mixture of buffers, ionic and non-ionic surfactants (FL-70 solution) together with a medium cross-flow density provided an acceptable compromise in peak quality and recovery for both types of ENPs. However, these separation conditions do not represent a perfect match for both particle types at the same time (maximized recovery at maximized retention). It could be shown that the behavior of particles within Flow-FFF channels cannot be predicted or explained purely in terms of electrostatic interactions. Particles were irreversibly lost under conditions where the measured zeta potentials suggested that there should have been sufficient electrostatic repulsion to ensure stabilization of the particles in the Flow-FFF channel resulting in good recoveries. The wide variations that we observed in ENP behavior under different conditions, together with the different

Susceptibility for thin ideal media and eating styles.

PubMed

Anschutz, Doeschka J; Engels, Rutger C M E; Van Strien, Tatjana

2008-03-01

This study examined the relations between susceptibility for thin ideal media and restrained, emotional and external eating, directly and indirectly through body dissatisfaction. Thin ideal media susceptibility, body dissatisfaction and eating styles were measured in a sample of 163 female students. Structural equation modelling was used for analyses, controlling for BMI. Higher susceptibility for thin ideal media was directly related to higher scores on all eating styles, and indirectly related to higher restrained and emotional eating through elevated levels of body dissatisfaction. So, thin ideal media susceptibility was not only related to restraint through body dissatisfaction, but also directly. Emotional eaters might be more vulnerable for negative affect, whereas external eaters might be more sensitive to external cues in general.

Internal-external flow integration for a thin ejector-flapped wing section

NASA Technical Reports Server (NTRS)

Woolard, H. W.

1979-01-01

Thin airfoil theories of an ejector flapped wing section are reviewed. The global matching of the external airfoil flow with the ejector internal flow and the overall ejector flapped wing section aerodynamic performance are examined. Mathematical models of the external and internal flows are presented. The delineation of the suction flow coefficient characteristics are discussed. The idealized lift performance of an ejector flapped wing relative to a jet augmented flapped wing are compared.

Details of Side Load Test Data and Analysis for a Truncated Ideal Contour Nozzle and a Parabolic Contour Nozzle

NASA Technical Reports Server (NTRS)

Ruf, Joseph H.; McDaniels, David M.; Brown, Andrew M.

2010-01-01

Two cold flow subscale nozzles were tested for side load characteristics during simulated nozzle start transients. The two test article contours were a truncated ideal and a parabolic. The current paper is an extension of a 2009 AIAA JPC paper on the test results for the same two nozzle test articles. The side load moments were measured with the strain tube approach in MSFC s Nozzle Test Facility. The processing techniques implemented to convert the strain gage signals into side load moment data are explained. Nozzle wall pressure profiles for separated nozzle flow at many NPRs are presented and discussed in detail. The effect of the test cell diffuser inlet on the parabolic nozzle s wall pressure profiles for separated flow is shown. The maximum measured side load moments for the two contours are compared. The truncated ideal contour s peak side load moment was 45% of that of the parabolic contour. The calculated side load moments, via mean-plus-three-standard-deviations at each nozzle pressure ratio, reproduced the characteristics and absolute values of measured maximums for both contours. The effect of facility vibration on the measured side load moments is quantified and the effect on uncertainty is calculated. The nozzle contour designs are discussed and the impact of a minor fabrication flaw in the nozzle contours is explained.

Promoting Spiritual Ideals through Design Thinking in Public Schools

ERIC Educational Resources Information Center

Tan, Charlene; Wong, Yew-Leong

2012-01-01

Against a backdrop of the debates on religious education in public or state schools, we argue for the introduction of "spiritual ideals" into the public school curriculum. We distinguish our notion of spiritual ideals from "religious ideals" as conceptualised by De Ruyter and Merry. While we agree with De Ruyter and Merry that…

Childhood Lifestyle and Clinical Determinants of Adult Ideal

PubMed Central

Laitinen, Tomi T.; Pahkala, Katja; Venn, Alison; Woo, Jessica G; Oikonen, Mervi; Dwyer, Terence; Mikkilä, Vera; Hutri-Kähönen, Nina; Smith, Kylie J.; Gall, Seana L.; Morrison, John A.; Viikari, Jorma S.A.; Raitakari, Olli T.; Magnussen, Costan G.; Juonala, Markus

2013-01-01

Background The American Heart Association recently defined ideal cardiovascular health by simultaneous presence of seven health behaviors and factors. The concept is associated with cardiovascular disease incidence, and cardiovascular disease and all-cause mortality. To effectively promote ideal cardiovascular health already early in life, childhood factors predicting future ideal cardiovascular health should be investigated. Our aim was thus to comprehensively explore childhood determinants of adult ideal cardiovascular health in population based cohorts from three continents. Methods The sample comprised a total of 4409 participants aged 3–19 years at baseline from the Cardiovascular Risk in Young Finns Study (YFS; N=1883) from Finland, Childhood Determinants of Adult Health Study (CDAH; N=1803) from Australia and Princeton Follow-up Study (PFS; N=723) from the United States. Participants were re-examined 19–31 years later when aged 30–48 years. Results In multivariable analyses, independent childhood predictors of adult ideal cardiovascular health were family socioeconomic status (P<0.01; direct association) and BMI (P<0.001; inverse association) in all cohorts. In addition, blood pressure (P=0.007), LDL-cholesterol (P<0.001) and parental smoking (P=0.006) in the YFS, and own smoking (P=0.001) in CDAH were inversely associated with future ideal cardiovascular health. Conclusions Among several lifestyle and clinical indicators studied, higher family socioeconomic status and non-smoking (parental/own) in childhood independently predict ideal cardiovascular health in adulthood. As atherosclerotic cardiovascular diseases are rooted in childhood, our findings suggest that special attention could be paid to children who are from low socioeconomic status families, and who smoke or whose parents smoke, to prevent cardiovascular disease morbidity and mortality. PMID:24075574

One-dimensional flows of an imperfect diatomic gas

NASA Technical Reports Server (NTRS)

1959-01-01

With the assumptions that Berthelot's equation of state accounts for molecular size and intermolecular force effects, and that changes in the vibrational heat capacities are given by a Planck term, expressions are developed for analyzing one-dimensional flows of a diatomic gas. The special cases of flow through normal and oblique shocks in free air at sea level are investigated. It is found that up to a Mach number 10 pressure ratio across a normal shock differs by less than 6 percent from its ideal gas value; whereas at Mach numbers above 4 the temperature rise is considerable below and hence the density rise is well above that predicted assuming ideal gas behavior. It is further shown that only the caloric imperfection in air has an appreciable effect on the pressures developed in the shock process considered. The effects of gaseous imperfections on oblique shock-flows are studied from the standpoint of their influence on the life and pressure drag of a flat plate operating at Mach numbers of 10 and 20. The influence is found to be small. (author)

A Numerical Study of the Non-Ideal Behavior, Parameters, and Novel Applications of an Electrothermal Plasma Source

NASA Astrophysics Data System (ADS)

Winfrey, A. Leigh

Electrothermal plasma sources have numerous applications including hypervelocity launchers, fusion reactor pellet injection, and space propulsion systems. The time evolution of important plasma parameters at the source exit is important in determining the suitability of the source for different applications. In this study a capillary discharge code has been modified to incorporate non-ideal behavior by using an exact analytical model for the Coulomb logarithm in the plasma electrical conductivity formula. Actual discharge currents from electrothermal plasma experiments were used and code results for both ideal and non-ideal plasma models were compared to experimental data, specifically the ablated mass from the capillary and the electrical conductivity as measured by the discharge current and the voltage. Electrothermal plasma sources operating in the ablation-controlled arc regime use discharge currents with pulse lengths between 100 micros to 1 ms. Faster or longer or extended flat-top pulses can also be generated to satisfy various applications of ET sources. Extension of the peak current for up to an additional 1000 micros was tested. Calculations for non-ideal and ideal plasma models show that extended flattop pulses produce more ablated mass, which scales linearly with increased pulse length while other parameters remain almost constant. A new configuration of the PIPE source has been proposed in order to investigate the formation of plasmas from mixed materials. The electrothermal segmented plasma source can be used for studies related to surface coatings, surface modification, ion implantation, materials synthesis, and the physics of complex mixed plasmas. This source is a capillary discharge where the ablation liner is made from segments of different materials instead of a single sleeve. This system should allow for the modeling and characterization of the growth plasma as it provides all materials needed for fabrication through the same method. An

On the union of graded prime ideals

NASA Astrophysics Data System (ADS)

Uregen, Rabia Nagehan; Tekir, Unsal; Hakan Oral, Kursat

2016-01-01

In this paper we investigate graded compactly packed rings, which is defined as; if any graded ideal I of R is contained in the union of a family of graded prime ideals of R, then I is actually contained in one of the graded prime ideals of the family. We give some characterizations of graded compactly packed rings. Further, we examine this property on h - Spec(R). We also define a generalization of graded compactly packed rings, the graded coprimely packed rings. We show that R is a graded compactly packed ring if and only if R is a graded coprimely packed ring whenever R be a graded integral domain and h - dim R = 1.

Using an Electronic Highlighter to Eliminate the Negative Effects of Pre-Existing, Inappropriate Highlighting

ERIC Educational Resources Information Center

Gier, Vicki; Kreiner, David; Hudnell, Jason; Montoya, Jodi; Herring, Daniel

2011-01-01

The purpose of the present experiment was to determine whether using an active learning technique, electronic highlighting, can eliminate the negative effects of pre-existing, poor highlighting on reading comprehension. Participants read passages containing no highlighting, appropriate highlighting, or inappropriate highlighting. We hypothesized…

Why Education in Public Schools Should Include Religious Ideals

ERIC Educational Resources Information Center

de Ruyter, Doret J.; Merry, Michael S.

2009-01-01

This article aims to open a new line of debate about religion in public schools by focusing on religious ideals. The article begins with an elucidation of the concept "religious ideals" and an explanation of the notion of reasonable pluralism, in order to be able to explore the dangers and positive contributions of religious ideals and their…

Idealization of the analyst by the young adult.

PubMed

Chused, J F

1987-01-01

Idealization is an intrapsychic process that serves many functions. In addition to its use defensively and for gratification of libidinal and aggressive drive derivatives, it can contribute to developmental progression, particularly during late adolescence and young adulthood. During an analysis, it is important to recognize all the determinants of idealization, including those related to the reworking of developmental conflicts. If an analyst understands idealization solely as a manifestation of pathology, he may interfere with his patient's use of it for the development of autonomous functioning.

Multidomain approach for calculating compressible flows

NASA Technical Reports Server (NTRS)

Cambier, L.; Chazzi, W.; Veuillot, J. P.; Viviand, H.

1982-01-01

A multidomain approach for calculating compressible flows by using unsteady or pseudo-unsteady methods is presented. This approach is based on a general technique of connecting together two domains in which hyperbolic systems (that may differ) are solved with the aid of compatibility relations associated with these systems. Some examples of this approach's application to calculating transonic flows in ideal fluids are shown, particularly the adjustment of shock waves. The approach is then applied to treating a shock/boundary layer interaction problem in a transonic channel.

Identification of ideal resuscitation pressure with concurrent traumatic brain injury in a rat model of hemorrhagic shock.

PubMed

Hu, Yi; Wu, Yue; Tian, Kunlun; Lan, Dan; Chen, Xiangyun; Xue, Mingying; Liu, Liangming; Li, Tao

2015-05-01

Traumatic brain injury (TBI) is often associated with uncontrolled hemorrhagic shock (UHS), which contributes significantly to the mortality of severe trauma. Studies have demonstrated that permissive hypotension resuscitation improves the survival for uncontrolled hemorrhage. What the ideal target mean arterial pressure (MAP) is for TBI with UHS remains unclear. With the rat model of TBI in combination with UHS, we investigated the effects of a series of target resuscitation pressures (MAP from 50-90 mm Hg) on animal survival, brain perfusion, and organ function before hemorrhage controlled. Rats in 50-, 60-, and 70-mm Hg target MAP groups had less blood loss and less fluid requirement, a better vital organ including mitochondrial function and better cerebral blood flow, and animal survival (8, 6, and 7 of 10, respectively) than 80- and 90-mm Hg groups. The 70-mm Hg group had a better cerebral blood flow and cerebral mitochondrial function than in 50- and 60-mm Hg groups. In contrast, 80- and 90-mm Hg groups resulted in an excessive hemodilution, a decreased blood flow, an increased brain water content, and more severe cerebral edema. A 50-mm Hg target MAP is not suitable for the resuscitation of TBI combined with UHS. A 70 mm Hg of MAP is the ideal target resuscitation pressure for this trauma, which can keep sufficient perfusion to the brain and keep good organ function including cerebral mitochondrial function. Copyright © 2015 Elsevier Inc. All rights reserved.

Real-gas effects associated with one-dimensional transonic flow of cryogenic nitrogen

NASA Technical Reports Server (NTRS)

Adcock, J. B.

1976-01-01

Real gas solutions for one-dimensional isentropic and normal-shock flows of nitrogen were obtained for a wide range of temperatures and pressures. These calculations are compared to ideal gas solutions and are presented in tables. For temperatures (300 K and below) and pressures (1 to 10 atm) that cover those anticipated for transonic cryogenic tunnels, the solutions are analyzed to obtain indications of the magnitude of inviscid flow simulation errors. For these ranges, the maximum deviation of the various isentropic and normal shock parameters from the ideal values is about 1 percent or less, and for most wind tunnel investigations this deviation would be insignificant.

Moral identity as moral ideal self: links to adolescent outcomes.

PubMed

Hardy, Sam A; Walker, Lawrence J; Olsen, Joseph A; Woodbury, Ryan D; Hickman, Jacob R

2014-01-01

The purposes of this study were to conceptualize moral identity as moral ideal self, to develop a measure of this construct, to test for age and gender differences, to examine links between moral ideal self and adolescent outcomes, and to assess purpose and social responsibility as mediators of the relations between moral ideal self and outcomes. Data came from a local school sample (Data Set 1: N = 510 adolescents; 10-18 years of age) and a national online sample (Data Set 2: N = 383 adolescents; 15-18 years of age) of adolescents and their parents. All outcome measures were parent-report (Data Set 1: altruism, moral personality, aggression, and cheating; Data Set 2: environmentalism, school engagement, internalizing, and externalizing), whereas other variables were adolescent-report. The 20-item Moral Ideal Self Scale showed good reliability, factor structure, and validity. Structural equation models demonstrated that, even after accounting for moral identity internalization, in Data Set 1 moral ideal self positively predicted altruism and moral personality and negatively predicted aggression, whereas in Data Set 2 moral ideal self positively predicted environmentalism and negatively predicted internalizing and externalizing symptoms. Further, purpose and social responsibility mediated most relations between moral ideal self and the outcomes in Data Set 2. Moral ideal self was unrelated to age but differentially predicted some outcomes across age. Girls had higher levels of moral ideal self than boys, although moral identity did not differentially predict outcomes between genders. Thus, moral ideal self is a salient element of moral identity and may play a role in morally relevant adolescent outcomes. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Turbulent Flow Validation in the Helios Strand Solver

DTIC Science & Technology

2014-01-07

usual (̄) notation is omitted for simplicity). The pressure is obtained from the ideal gas equation of state given as: P = (γ−1) [ Et − 1 2 ρ ( u2 + v2...2. SA-RANS System The state vector and flux vectors including those of the SA model equation for three-dimensional flow are explicitly given as: u...number, PrT is the turbulent Prandtl number, and T is the temperature. The ideal gas equation of state , p = ρRT is used to close the equations . IV.A

[Challenges and risks in the development of the ego ideal in adolescence].

PubMed

Helbing-Tietze, Brigitte

2003-11-01

The author proposes to speak of representations concerning the ideal self, the ideal relationship, the ideal society instead of ego ideal. An active self develops ideals and uses them as standards for orientation, to regulate the affects, and to fulfill needs. The different ideals often do not fit together and are therefore difficult to realize. Adolescents normally refuse their parents' ideals and create new ones with the help of their peers. This developmental step is full of challenges and risks as will be explained in this article.

An Idealized, Single Radial Swirler, Lean-Direct-Injection (LDI) Concept Meshing Script

NASA Technical Reports Server (NTRS)

Iannetti, Anthony C.; Thompson, Daniel

2008-01-01

To easily study combustor design parameters using computational fluid dynamics codes (CFD), a Gridgen Glyph-based macro (based on the Tcl scripting language) dubbed BladeMaker has been developed for the meshing of an idealized, single radial swirler, lean-direct-injection (LDI) combustor. BladeMaker is capable of taking in a number of parameters, such as blade width, blade tilt with respect to the perpendicular, swirler cup radius, and grid densities, and producing a three-dimensional meshed radial swirler with a can-annular (canned) combustor. This complex script produces a data format suitable for but not specific to the National Combustion Code (NCC), a state-of-the-art CFD code developed for reacting flow processes.

The ideal subject distance for passport pictures.

PubMed

Verhoff, Marcel A; Witzel, Carsten; Kreutz, Kerstin; Ramsthaler, Frank

2008-07-04

In an age of global combat against terrorism, the recognition and identification of people on document images is of increasing significance. Experiments and calculations have shown that the camera-to-subject distance - not the focal length of the lens - can have a significant effect on facial proportions. Modern passport pictures should be able to function as a reference image for automatic and manual picture comparisons. This requires a defined subject distance. It is completely unclear which subject distance, in the taking of passport photographs, is ideal for the recognition of the actual person. We show here that the camera-to-subject distance that is perceived as ideal is dependent on the face being photographed, even if the distance of 2m was most frequently preferred. So far the problem of the ideal camera-to-subject distance for faces has only been approached through technical calculations. We have, for the first time, answered this question experimentally with a double-blind experiment. Even if there is apparently no ideal camera-to-subject distance valid for every face, 2m can be proposed as ideal for the taking of passport pictures. The first step would actually be the determination of a camera-to-subject distance for the taking of passport pictures within the standards. From an anthropological point of view it would be interesting to find out which facial features allow the preference of a shorter camera-to-subject distance and which allow the preference of a longer camera-to-subject distance.

Flow chemistry meets advanced functional materials.

PubMed

Myers, Rebecca M; Fitzpatrick, Daniel E; Turner, Richard M; Ley, Steven V

2014-09-22

Flow chemistry and continuous processing techniques are beginning to have a profound impact on the production of functional materials ranging from quantum dots, nanoparticles and metal organic frameworks to polymers and dyes. These techniques provide robust procedures which not only enable accurate control of the product material's properties but they are also ideally suited to conducting experiments on scale. The modular nature of flow and continuous processing equipment rapidly facilitates reaction optimisation and variation in function of the products. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Workshops on Volcanoes at Santiaguito (Guatemala): A community effort to inform and highlight the outstanding science opportunities at an exceptional laboratory volcano

NASA Astrophysics Data System (ADS)

Johnson, J. B.; Escobar-Wolf, R. P.; Pineda, A.

2016-12-01

Santiaguito is one of Earth's most reliable volcanic spectacles and affords opportunity to investigate dome volcanism, including hourly explosions, pyroclastic flows, block lava flows, and sporadic paroxysmal eruptions. The cubic km dome, active since 1922, comprises four coalescing structures. Lava effusion and explosions are ideally observed from a birds-eye perspective at the summit of Santa Maria volcano (1200 m above and 2700 km from the active Caliente vent). Santiaguito is also unstable and dangerous. Thousands of people in farms and local communities are exposed to hazards from frequent lahars, pyroclastic flows, and potentially large sector-style dome collapses. In January 2016 more than 60 volcano scientists, students, postdocs, and observatory professionals traveled to Santiaguito to participate in field study and discussion about the science and hazards of Santiaguito. The event facilitated pre- and syn-workshop field experiments, including deployment of seismic, deformation, infrasound, multi-spectral gas and thermal sensing, UAV reconnaissance, photogrammetry, and petrologic and rheologic sampling. More than 55 participants spent the night on the 3770-m summit of Santa Maria to partake in field observations. The majority of participants also visited lahar and pyroclastic flow-impacted regions south of the volcano. A goal of the workshop was to demonstrate how multi-disciplinary observations are critical to elucidate volcano eruption dynamics. Integration of geophysical and geochemical observation, and open exchange of technological advances, is vital to achieve the next generation of volcano discovery. Toward this end data collected during the workshop are openly shared within the broader volcanological community. Another objective of the workshop was to bring attention to an especially hazardous and little-studied volcanic system. The majority of workshop attendees had not visited the region and their participation was hoped to seed future

Spaces of ideal convergent sequences.

PubMed

Mursaleen, M; Sharma, Sunil K

2014-01-01

In the present paper, we introduce some sequence spaces using ideal convergence and Musielak-Orlicz function ℳ = (M(k)). We also examine some topological properties of the resulting sequence spaces.

Effect of solution non-ideality on erythrocyte volume regulation.

PubMed

Levin, R L; Cravalho, E G; Huggins, C E

1977-03-01

A non-ideal, hydrated, non-dilute pseudo-binary salt-protein-water solution model of the erythrocyte intracellular solution is presented to describe the osmotic behavior of human erythrocytes. Existing experimental activity data for salts and proteins in aqueous solutions are used to formulate van Laar type expressions for the solvent and solute activity coefficients. Reasonable estimates can therefore be made of the non-ideality of the erythrocyte intracellular solution over a wide range of osmolalities. Solution non-ideality is shown to affect significantly the degree of solute polarization within the erythrocyte intracellular solution during freezing. However, the non-ideality has very little effect upon the amount of water retained within erythrocytes cooled at sub-zero temperatures.

Eye wash water flow direction study: an evaluation of the effectiveness of eye wash devices with opposite directional water flow.

PubMed

Fogt, Jennifer S; Jones-Jordan, Lisa A; Barr, Joseph T

2018-01-01

New designs of eye wash stations have been developed in which the direction of water flow from the fountain has been reversed, with two water streams originating nasally in both eyes and flowing toward the temporal side of each eye. No study has been done to determine the ideal direction of water flow coming from the eye wash in relation to the eye. Ophthalmic eye examinations were conducted before and after the use of two eye wash stations with opposite water flow directionality. Fluorescein was instilled in both eyes before using an eye wash to measure the effectiveness of the water flow. Subjects were surveyed upon their experiences using the eye washes. Ophthalmic examination found no significant difference in the efficacy of the eye washes with nasal-to-temporal water flow when compared to temporal-to-nasal water flow direction.

Mass flow and velocity profiles in Neurospora hyphae: partial plug flow dominates intra-hyphal transport.

PubMed

Abadeh, Aryan; Lew, Roger R

2013-11-01

Movement of nuclei, mitochondria and vacuoles through hyphal trunks of Neurospora crassa were vector-mapped using fluorescent markers and green fluorescent protein tags. The vectorial movements of all three were strongly correlated, indicating the central role of mass (bulk) flow in cytoplasm movements in N. crassa. Profiles of velocity versus distance from the hyphal wall did not match the parabolic shape predicted by the ideal Hagen-Poiseuille model of flow at low Reynolds number. Instead, the profiles were flat, consistent with a model of partial plug flow due to the high concentration of organelles in the flowing cytosol. The intra-hyphal pressure gradients were manipulated by localized external osmotic treatments to demonstrate the dependence of velocity (and direction) on pressure gradients within the hyphae. The data support the concept that mass transport, driven by pressure gradients, dominates intra-hyphal transport. The transport occurs by partial plug flow due to the organelles in the cytosol.

Pollutant Plume Dispersion in the Atmospheric Boundary Layer over Idealized Urban Roughness

NASA Astrophysics Data System (ADS)

Wong, Colman C. C.; Liu, Chun-Ho

2013-05-01

The Gaussian model of plume dispersion is commonly used for pollutant concentration estimates. However, its major parameters, dispersion coefficients, barely account for terrain configuration and surface roughness. Large-scale roughness elements (e.g. buildings in urban areas) can substantially modify the ground features together with the pollutant transport in the atmospheric boundary layer over urban roughness (also known as the urban boundary layer, UBL). This study is thus conceived to investigate how urban roughness affects the flow structure and vertical dispersion coefficient in the UBL. Large-eddy simulation (LES) is carried out to examine the plume dispersion from a ground-level pollutant (area) source over idealized street canyons for cross flows in neutral stratification. A range of building-height-to-street-width (aspect) ratios, covering the regimes of skimming flow, wake interference, and isolated roughness, is employed to control the surface roughness. Apart from the widely used aerodynamic resistance or roughness function, the friction factor is another suitable parameter that measures the drag imposed by urban roughness quantitatively. Previous results from laboratory experiments and mathematical modelling also support the aforementioned approach for both two- and three-dimensional roughness elements. Comparing the UBL plume behaviour, the LES results show that the pollutant dispersion strongly depends on the friction factor. Empirical studies reveal that the vertical dispersion coefficient increases with increasing friction factor in the skimming flow regime (lower resistance) but is more uniform in the regimes of wake interference and isolated roughness (higher resistance). Hence, it is proposed that the friction factor and flow regimes could be adopted concurrently for pollutant concentration estimate in the UBL over urban street canyons of different roughness.

Field-flow fractionation and hydrodynamic chromatography on a microfluidic chip.

PubMed

Shendruk, Tyler N; Tahvildari, Radin; Catafard, Nicolas M; Andrzejewski, Lukasz; Gigault, Christian; Todd, Andrew; Gagne-Dumais, Laurent; Slater, Gary W; Godin, Michel

2013-06-18

We present gravitational field-flow fractionation and hydrodynamic chromatography of colloids eluting through 18 μm microchannels. Using video microscopy and mesoscopic simulations, we investigate the average retention ratio of colloids with both a large specific weight and neutral buoyancy. We consider the entire range of colloid sizes, including particles that barely fit in the microchannel and nanoscopic particles. Ideal theory predicts four operational modes, from hydrodynamic chromatography to Faxén-mode field-flow fractionation. We experimentally demonstrate, for the first time, the existence of the Faxén-mode field-flow fractionation and the transition from hydrodynamic chromatography to normal-mode field-flow fractionation. Furthermore, video microscopy and simulations show that the retention ratios are largely reduced above the steric-inversion point, causing the variation of the retention ratio in the steric- and Faxén-mode regimes to be suppressed due to increased drag. We demonstrate that theory can accurately predict retention ratios if hydrodynamic interactions with the microchannel walls (wall drag) are added to the ideal theory. Rather than limiting the applicability, these effects allow the microfluidic channel size to be tuned to ensure high selectivity. Our findings indicate that particle velocimetry methods must account for the wall-induced lag when determining flow rates in highly confining systems.

Coupling Ideality of Integrated Planar High-Q Microresonators

NASA Astrophysics Data System (ADS)

Pfeiffer, Martin H. P.; Liu, Junqiu; Geiselmann, Michael; Kippenberg, Tobias J.

2017-02-01

Chip-scale optical microresonators with integrated planar optical waveguides are useful building blocks for linear, nonlinear, and quantum-optical photonic devices alike. Loss reduction through improving fabrication processes results in several integrated microresonator platforms attaining quality (Q ) factors of several millions. Beyond the improvement of the quality factor, the ability to operate the microresonator with high coupling ideality in the overcoupled regime is of central importance. In this regime, the dominant source of loss constitutes the coupling to a single desired output channel, which is particularly important not only for quantum-optical applications such as the generation of squeezed light and correlated photon pairs but also for linear and nonlinear photonics. However, to date, the coupling ideality in integrated photonic microresonators is not well understood, in particular, design-dependent losses and their impact on the regime of high ideality. Here we investigate design-dependent parasitic losses described by the coupling ideality of the commonly employed microresonator design consisting of a microring-resonator waveguide side coupled to a straight bus waveguide, a system which is not properly described by the conventional input-output theory of open systems due to the presence of higher-order modes. By systematic characterization of multimode high-Q silicon nitride microresonator devices, we show that this design can suffer from low coupling ideality. By performing 3D simulations, we identify the coupling to higher-order bus waveguide modes as the dominant origin of parasitic losses which lead to the low coupling ideality. Using suitably designed bus waveguides, parasitic losses are mitigated with a nearly unity ideality and strong overcoupling (i.e., a ratio of external coupling to internal resonator loss rate >9 ) are demonstrated. Moreover, we find that different resonator modes can exchange power through the coupler, which, therefore

Non-ideal magnetohydrodynamics on a moving mesh

NASA Astrophysics Data System (ADS)

Marinacci, Federico; Vogelsberger, Mark; Kannan, Rahul; Mocz, Philip; Pakmor, Rüdiger; Springel, Volker

2018-05-01

In certain astrophysical systems, the commonly employed ideal magnetohydrodynamics (MHD) approximation breaks down. Here, we introduce novel explicit and implicit numerical schemes of ohmic resistivity terms in the moving-mesh code AREPO. We include these non-ideal terms for two MHD techniques: the Powell 8-wave formalism and a constrained transport scheme, which evolves the cell-centred magnetic vector potential. We test our implementation against problems of increasing complexity, such as one- and two-dimensional diffusion problems, and the evolution of progressive and stationary Alfvén waves. On these test problems, our implementation recovers the analytic solutions to second-order accuracy. As first applications, we investigate the tearing instability in magnetized plasmas and the gravitational collapse of a rotating magnetized gas cloud. In both systems, resistivity plays a key role. In the former case, it allows for the development of the tearing instability through reconnection of the magnetic field lines. In the latter, the adopted (constant) value of ohmic resistivity has an impact on both the gas distribution around the emerging protostar and the mass loading of magnetically driven outflows. Our new non-ideal MHD implementation opens up the possibility to study magneto-hydrodynamical systems on a moving mesh beyond the ideal MHD approximation.

Computer program determines gas flow rates in piping systems

NASA Technical Reports Server (NTRS)

Franke, R.

1966-01-01

Computer program calculates the steady state flow characteristics of an ideal compressible gas in a complex piping system. The program calculates the stagnation and total temperature, static and total pressure, loss factor, and forces on each element in the piping system.

Sharp Truncation of an Electric Field: An Idealized Model that Warrants Caution

NASA Astrophysics Data System (ADS)

Tu, Hong; Zhu, Jiongming

2016-03-01

In physics, idealized models are often used to simplify complex situations. The motivation of the idealization is to make the real complex system tractable by adopting certain simplifications. In this treatment some unnecessary, negligible aspects are stripped away (so-called Aristotelian idealization), or some deliberate distortions are involved (so-called Galilean idealization). The most important principle in using an idealized model is to make sure that all the neglected aspects do not affect our analysis or result. Point charges, rigid bodies, simple pendulums, frictionless planes, and isolated systems are all frequently used idealized models. However, when they are applied to certain uncommon models, extra precautions should be taken. The possibilities and necessities of adopting the idealizations have to be considered carefully. Sometimes some factors neglected or ignored in the idealization could completely change the result, even make the treatment unphysical and conclusions unscientific.

[Tuberculosis and the modern ideal of living].

PubMed

Medici, T C

2003-08-20

Sunlight and fresh air belong to the everyday life's myths. It has influenced our times and personal lives as much as industrialization. Today we are hardly aware of the multiple and omnipresent consequences of this myth. The modern movement with all its facets including modern architecture is barely conceivable without it. What is the link between this triad with all its effects and tuberculosis, the oldest and most important infectious disease which still claims more than 3 million deaths per year worldwide? Tuberculosis was treated by sunlight and fresh air at all times. This treatment was at its zenith during the second half of the 19th century after Hermann Brehmer had initiated this treatment within sanatoria in 1862. The sanatorium vogue lasted until the middle of the last century when streptomycin was isolated by Selman Waksman 1943. A new type of hospital was necessary for treating the patients with sunlight and fresh air: the sanatorium with its wide windows, sheltered open balconies, terraces and "Liegehallen". In return, this airy type of building was the forrunner of a new architectural style, called "Neues Bauen". The latter has profoundly influenced our modern ideal of living since Le Corbusiier built the Villa Savoye, one of the architectural highlights of the 20th century.

Moral Identity as Moral Ideal Self: Links to Adolescent Outcomes

ERIC Educational Resources Information Center

Hardy, Sam A.; Walker, Lawrence J.; Olsen, Joseph A.; Woodbury, Ryan D.; Hickman, Jacob R.

2014-01-01

The purposes of this study were to conceptualize moral identity as moral ideal self, to develop a measure of this construct, to test for age and gender differences, to examine links between moral ideal self and adolescent outcomes, and to assess purpose and social responsibility as mediators of the relations between moral ideal self and outcomes.…

Singular flow dynamics in three space dimensions driven by advection

NASA Astrophysics Data System (ADS)

Karimov, A. R.; Schamel, H.

2002-03-01

The initial value problem of an ideal, compressible fluid is investigated in three space dimensions (3D). Starting from a situation where the inertia terms dominate over the force terms in Euler's equation we explore by means of the Lagrangian flow description the basic flow properties. Special attention is drawn to the appearance of singularities in the flow pattern at finite time. Classes of initial velocity profiles giving rise to collapses of density and vorticity are found. This paper, hence, furnishes evidence of focused singularities for coherent structures obeying the 3D Euler equation and applies to potential as well as vortex flows.

Jung's Red Book and its relation to aspects of German idealism.

PubMed

Bishop, Paul

2012-06-01

The late nineteenth century saw a renaissance of interest in the thought of the German Romantic philosopher, F.W.J. Schelling. This paper takes Jung's engagement with Schelling and his awareness of Schellingian ideas and interests (notably, the mysterious Kabeiroi worshipped at Samothrace) as its starting-point. It goes on to argue that a key set of problematics in German Idealism - the relation between freedom and necessity, between science and art, and ultimately between realism and idealism - offers a useful conceptual framework within which to approach Jung's Red Book. For the problem of the ideal is central to this work, which can be read as a journey from eternal ideals to the ideal of eternity. (Although the term 'idealism' has at least four distinct meanings, their distinct senses can be related in different ways to Jung's thinking.) The eloquent embrace of idealism by F.T. Vischer in a novel, Auch Einer, for which Jung had the highest praise, reminds us of the persistence of this tradition, which is still contested and debated in the present day. © 2012, The Society of Analytical Psychology.

A Generalized Deduction of the Ideal-Solution Model

ERIC Educational Resources Information Center

Leo, Teresa J.; Perez-del-Notario, Pedro; Raso, Miguel A.

2006-01-01

A new general procedure for deriving the Gibbs energy of mixing is developed through general thermodynamic considerations, and the ideal-solution model is obtained as a special particular case of the general one. The deduction of the Gibbs energy of mixing for the ideal-solution model is a rational one and viewed suitable for advanced students who…

On the Divergence of the Velocity Vector in Real-Gas Flow

NASA Technical Reports Server (NTRS)

Bellan, Josette

2009-01-01

A theoretical study was performed addressing the degree of applicability or inapplicability, to a real gas, of the occasionally stated belief that for an ideal gas, incompressibility is synonymous with a zero or very low Mach number. The measure of compressibility used in this study is the magnitude of the divergence of the flow velocity vector [V(bar) (raised dot) u (where u is the flow velocity)]. The study involves a mathematical derivation that begins with the governing equations of flow and involves consideration of equations of state, thermodynamics, and fluxes of heat, mass, and the affected molecular species. The derivation leads to an equation for the volume integral of (V(bar) (raised dot) u)(sup 2) that indicates contributions of several thermodynamic, hydrodynamic, and species-flux effects to compressibility and reveals differences between real and ideal gases. An analysis of the equation leads to the conclusion that for a real gas, incompressibility is not synonymous with zero or very small Mach number. Therefore, it is further concluded, the contributions to compressibility revealed by the derived equation should be taken into account in simulations of real-gas flows.

Ideal Cardiovascular Health and Arterial Stiffness in Spanish Adults-The EVIDENT Study.

PubMed

García-Hermoso, Antonio; Martínez-Vizcaíno, Vicente; Gomez-Marcos, Manuel Ángel; Cavero-Redondo, Iván; Recio-Rodriguez, José Ignacio; García-Ortiz, Luis

2018-05-01

Studies concerning ideal cardiovascular (CV) health and its relationship with arterial stiffness are lacking. This study examined the association between arterial stiffness with ideal CV health as defined by the American Heart Association, across age groups and gender. The cross-sectional study included 1365 adults. Ideal CV health was defined as meeting ideal levels of the following components: 4 behaviors (smoking, body mass index, physical activity, and Mediterranean diet adherence) and 3 factors (total cholesterol, blood pressure, and glycated hemoglobin). Patients were grouped into 3 categories according to their number of ideal CV health metrics: ideal (5-7 metrics), intermediate (3-4 metrics), and poor (0-2 metrics). We analyzed the pulse wave velocity (PWV), the central and radial augmentation indexes, and the ambulatory arterial stiffness index (AASI). The ideal CV health profile was inversely associated with lower arterial radial augmentation index and AASI in both genders, particularly in middle-aged (45-65 years) and in elderly subjects (>65 years). Also in elderly subjects, adjusted models showed that adults with at least 3 health metrics at ideal levels had significantly lower PWV than those with 2 or fewer ideal health metrics. An association was found between a favorable level of ideal CV health metrics and lower arterial stiffness across age groups. Copyright © 2018 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Ideal-Magnetohydrodynamic-Stable Tilting in Field-Reversed Configurations

NASA Astrophysics Data System (ADS)

Kanno, Ryutaro; Ishida, Akio; Steinhauer, Loren

1995-02-01

The tilting mode in field-reversed configurations (FRC) is examined using ideal-magnetohydrodynamic stability theory. Tilting, a global mode, is the greatest threat for disruption of FRC confinement. Previous studies uniformly found tilting to be unstable in ideal theory: the objective here is to ascertain if stable equilibria were overlooked in past work. Solving the variational problem with the Rayleigh-Ritz technique, tilting-stable equilibria are found for sufficiently hollow current profile and sufficient racetrackness of the separatrix shape. Although these equilibria were not examined previously, the present conclusion is quite surprising. Consequently checks of the method are offered. Even so it cannot yet be claimed with complete certainty that stability has been proved: absolute confirmation of ideal-stable tilting awaits the application of more complete methods.

Some Effects of Compressibility on the Flow Through Fans and Turbines

NASA Technical Reports Server (NTRS)

Perl, W.; Epstein, H. T.

1946-01-01

The laws of conservation of mass, momentum, and energy are applied to the compressible flow through a two-dimensional cascade of airfoils. A fundamental relation between the ultimate upstream and downstream flow angles, the inlet Mach number, and the pressure ratio across the cascade is derived. Comparison with the corresponding relation for incompressible flow shows large differences. The fundamental relation reveals two ranges of flow angles and inlet Mach numbers, for which no ideal pressure ratio exists. One of these nonideal operating ranges is analogous to a similar type in incompressible flow. The other is characteristic only of compressible flow. The effect of variable axial-flow area is treated. Some implications of the basic conservation laws in the case of nonideal flow through cascades are discussed.

Primitive ideals of C q [ SL(3)

NASA Astrophysics Data System (ADS)

Hodges, Timothy J.; Levasseur, Thierry

1993-10-01

The primitive ideals of the Hopf algebra C q [ SL(3)] are classified. In particular it is shown that the orbits in Prim C q [ SL(3)] under the action of the representation group H ≅ C *× C * are parameterized naturally by W×W, where W is the associated Weyl group. It is shown that there is a natural one-to-one correspondence between primitive ideals of C q [ SL(3)] and symplectic leaves of the associated Poisson algebraic group SL(3, C).

Temperature and the Ideal Gas

ERIC Educational Resources Information Center

Daisley, R. E.

1973-01-01

Presents some organized ideas in thermodynamics which are suitable for use with high school (GCE A level or ONC) students. Emphases are placed upon macroscopic observations and intimate connection of the modern definition of temperature with the concept of ideal gas. (CC)

Studies on unsaturated flow in dual-scale fiber fabrics

NASA Astrophysics Data System (ADS)

Yan, Fei; Yan, Shilin; Li, Yongjing

2018-03-01

Fiber fabrics in liquid composite molding (LCM) can be recognized as a dual-scale structure. As sink theory developed, this unsaturated flow behavior has already been simulated successfully; however, most of simulated results based on a unit cell under ideal status, thus making results were not agreement with experiment. In this study, an experimental method to establish sink function was proposed. After compared the simulation results by this sink function, it shows high accuracy with the experimental data. Subsequently, the key influencing factors for unsaturated flow have been further investigated; results show that the filling time for unsaturated flow was much longer than saturated flow. In addition, the injection pressure and permeability were the key factors lead to unsaturated flow.

Ideal photon number amplifier and duplicator

NASA Technical Reports Server (NTRS)

Dariano, G. M.

1992-01-01

The photon number-amplification and number-duplication mechanism are analyzed in the ideal case. The search for unitary evolutions leads to consider also a number-deamplification mechanism, the symmetry between amplification and deamplification being broken by the integer-value nature of the number operator. Both transformations, amplification and duplication, need an auxiliary field which, in the case of amplification, turns out to be amplified in the inverse way. Input-output energy conservation is accounted for using a classical pump or through frequency-conversion of the fields. Ignoring one of the fields is equivalent to considering the amplifier as an open system involving entropy production. The Hamiltonians of the ideal devices are given and compared with those of realistic systems.

Innovation in neurosurgery: less than IDEAL? A systematic review.

PubMed

Muskens, I S; Diederen, S J H; Senders, J T; Zamanipoor Najafabadi, A H; van Furth, W R; May, A M; Smith, T R; Bredenoord, A L; Broekman, M L D

2017-10-01

Surgical innovation is different from the introduction of novel pharmaceuticals. To help address this, in 2009 the IDEAL Collaboration (Idea, Development, Exploration, Assessment, Long-term follow-up) introduced the five-stage framework for surgical innovation. To evaluate the framework feasibility for novel neurosurgical procedure introduction, two innovative surgical procedures were examined: the endoscopic endonasal approach for skull base meningiomas (EEMS) and the WovenEndobridge (WEB device) for endovascular treatment of intracranial aneurysms. The published literature on EEMS and WEB devices was systematically reviewed. Identified studies were classified according to the IDEAL framework stage. Next, studies were evaluated for possible categorization according to the IDEAL framework. Five hundred seventy-six papers describing EEMS were identified of which 26 papers were included. No prospective studies were identified, and no studies reported on ethical approval or patient informed consent for the innovative procedure. Therefore, no clinical studies could be categorized according to the IDEAL Framework. For WEB devices, 6229 articles were screened of which 21 were included. In contrast to EEMS, two studies were categorized as 2a and two as 2b. The results of this systematic review demonstrate that both EEMS and WEB devices were not introduced according to the (later developed in the case of EEMS) IDEAL framework. Elements of the framework such as informed consent, ethical approval, and rigorous outcomes reporting are important and could serve to improve the quality of neurosurgical research. Alternative study designs and the use of big data could be useful modifications of the IDEAL framework for innovation in neurosurgery.

Piecewise uniform conduction-like flow channels and method therefor

DOEpatents

Cummings, Eric B [Livermore, CA; Fiechtner, Gregory J [Livermore, CA

2006-02-28

A low-dispersion methodology for designing microfabricated conduction channels for on-chip electrokinetic-based systems is presented. The technique relies on trigonometric relations that apply for ideal electrokinetic flows, allowing faceted channels to be designed on chips using common drafting software and a hand calculator. Flows are rotated and stretched along the abrupt interface between adjacent regions with differing permeability. Regions bounded by interfaces form flow "prisms" that can be combined with other designed prisms to obtain a wide range of turning angles and expansion ratios while minimizing dispersion. Designs are demonstrated using two-dimensional numerical solutions of the Laplace equation.

Partially-Averaged Navier-Stokes (PANS) approach for study of fluid flow and heat transfer characteristics in Czochralski melt

NASA Astrophysics Data System (ADS)

Verma, Sudeep; Dewan, Anupam

2018-01-01

The Partially-Averaged Navier-Stokes (PANS) approach has been applied for the first time to model turbulent flow and heat transfer in an ideal Czochralski set up with the realistic boundary conditions. This method provides variable level of resolution ranging from the Reynolds-Averaged Navier-Stokes (RANS) modelling to Direct Numerical Simulation (DNS) based on the filter control parameter. For the present case, a low-Re PANS model has been developed for Czochralski melt flow, which includes the effect of coriolis, centrifugal, buoyant and surface tension induced forces. The aim of the present study is to assess improvement in results on switching to PANS modelling from unsteady RANS (URANS) approach on the same computational mesh. The PANS computed results were found to be in good agreement with the reported experimental, DNS and Large Eddy Simulation (LES) data. A clear improvement in computational accuracy is observed in switching from the URANS approach to the PANS methodology. The computed results further improved with a reduction in the PANS filter width. Further the capability of the PANS model to capture key characteristics of the Czochralski crystal growth is also highlighted. It was observed that the PANS model was able to resolve the three-dimensional turbulent nature of the melt, characteristic flow structures arising due to flow instabilities and generation of thermal plumes and vortices in the Czochralski melt.

Elastin: a representative ideal protein elastomer.

PubMed Central

Urry, D W; Hugel, T; Seitz, M; Gaub, H E; Sheiba, L; Dea, J; Xu, J; Parker, T

2002-01-01

During the last half century, identification of an ideal (predominantly entropic) protein elastomer was generally thought to require that the ideal protein elastomer be a random chain network. Here, we report two new sets of data and review previous data. The first set of new data utilizes atomic force microscopy to report single-chain force-extension curves for (GVGVP)(251) and (GVGIP)(260), and provides evidence for single-chain ideal elasticity. The second class of new data provides a direct contrast between low-frequency sound absorption (0.1-10 kHz) exhibited by random-chain network elastomers and by elastin protein-based polymers. Earlier composition, dielectric relaxation (1-1000 MHz), thermoelasticity, molecular mechanics and dynamics calculations and thermodynamic and statistical mechanical analyses are presented, that combine with the new data to contrast with random-chain network rubbers and to detail the presence of regular non-random structural elements of the elastin-based systems that lose entropic elastomeric force upon thermal denaturation. The data and analyses affirm an earlier contrary argument that components of elastin, the elastic protein of the mammalian elastic fibre, and purified elastin fibre itself contain dynamic, non-random, regularly repeating structures that exhibit dominantly entropic elasticity by means of a damping of internal chain dynamics on extension. PMID:11911774

Hypervelocity flows of argon produced in a free piston driven expansion tube

NASA Technical Reports Server (NTRS)

Neely, A. J.; Stalker, R. J.

1992-01-01

An expansion tube with a free piston driver has been used to generate quasi-steady hypersonic flows in argon at flow velocities in excess of 9 km/s. Irregular test flow unsteadiness has limited the performance of previous expansion tubes. Test section measurements of pitot pressure, static pressure, and flat plate heat transfer rates are used to confirm the presence of quasi-steady flow, and comparisons are made with predictions for the equilibrium flow of an ideal, ionizing, monatomic gas. The results of this work indicate that expansion tubes can be used to generate quasi-steady hypersonic flows in argon at speeds in excess of Earth orbital velocity.

Topological photonic crystal with ideal Weyl points

NASA Astrophysics Data System (ADS)

Wang, Luyang; Jian, Shao-Kai; Yao, Hong

Weyl points in three-dimensional photonic crystals behave as monopoles of Berry flux in momentum space. Here, based on symmetry analysis, we show that a minimal number of symmetry-related Weyl points can be realized in time-reversal invariant photonic crystals. We propose to realize these ``ideal'' Weyl points in modified double-gyroid photonic crystals, which is confirmed by our first-principle photonic band-structure calculations. Photonic crystals with ideal Weyl points are qualitatively advantageous in applications such as angular and frequency selectivity, broadband invisibility cloaking, and broadband 3D-imaging.

Determination of performance of non-ideal aluminized explosives.

PubMed

Keshavarz, Mohammad Hossein; Mofrad, Reza Teimuri; Poor, Karim Esmail; Shokrollahi, Arash; Zali, Abbas; Yousefi, Mohammad Hassan

2006-09-01

Non-ideal explosives can have Chapman-Jouguet (C-J) detonation pressure significantly different from those expected from existing thermodynamic computer codes, which usually allows finding the parameters of ideal detonation of individual high explosives with good accuracy. A simple method is introduced by which detonation pressure of non-ideal aluminized explosives with general formula C(a)H(b)N(c)O(d)Al(e) can be predicted only from a, b, c, d and e at any loading density without using any assumed detonation products and experimental data. Calculated detonation pressures show good agreement with experimental values with respect to computed results obtained by complicated computer code. It is shown here how loading density and atomic composition can be integrated into an empirical formula for predicting detonation pressure of proposed aluminized explosives.

Effect of coolant flow ejection on aerodynamic performance of low-aspect-ratio vanes. 1: Performance with coolant ejection holes plugged

NASA Technical Reports Server (NTRS)

Haas, J. E.; Kofskey, M. G.

1976-01-01

The aerodynamic performance of a low aspect ratio turbine vane designed with coolant flow ejection holes on the vane surfaces was experimentally determined in a full-annular cascade with the coolant ejection holes plugged. The purpose was to establish a baseline for comparison with tests where flow is ejected from the vane surfaces. The vanes were tested over a mean-section ideal critical velocity ratio range of 0.64 to 0.98. This ideal critical velocity ratio corresponds to the vane inlet total to vane aftermixed static pressure ratio at the mean section. The variations in vane efficiency and aftermixed flow conditions with circumferential and radial position were obtained.

Prevalence of ideal cardiovascular health in European adolescents: The HELENA study.

PubMed

Henriksson, Pontus; Henriksson, Hanna; Gracia-Marco, Luis; Labayen, Idoia; Ortega, Francisco B; Huybrechts, Inge; España-Romero, Vanesa; Manios, Yannis; Widhalm, Kurt; Dallongeville, Jean; González-Gross, Marcela; Marcos, Ascensión; Moreno, Luis A; Castillo, Manuel J; Ruiz, Jonatan R

2017-08-01

The ideal cardiovascular health (iCVH) construct consists of 4 health behaviours and 3 health factors and is strongly related to later cardiovascular disease. However, the prevalence of iCVH in European adolescents is currently unknown. The Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study is a cross-sectional, multicentre study conducted in 9 European countries during 2006-2007 and included 3528 adolescents (1683 boys and 1845 girls) between 12.5 and 17.5years of age. Status (ideal vs. non-ideal) for the health behaviours (smoking status, body mass index, physical activity and diet) and health factors (total cholesterol, blood pressure and fasting glucose) were determined. Overall, the prevalence of ideal health behaviours was low; non-smoking (60.9% ideal), body mass index (76.8%), physical activity (62.1%), and diet (1.7%). The prevalence of ideal health factors was; total cholesterol (65.8%), blood pressure (62.0%) and plasma glucose (88.8%). The low prevalence of iCVH behaviours, especially diet and physical activity, identified in European adolescents is likely to influence later cardiovascular health which strongly motivates efforts to increase ideal health behaviours in this population. Copyright © 2017 Elsevier B.V. All rights reserved.

Ideal affect in daily life: implications for affective experience, health, and social behavior.

PubMed

Tsai, Jeanne L

2017-10-01

Over the last decade, researchers have increasingly demonstrated that ideal affect-the affective states that people value and ideally want to feel-shapes different aspects of daily life. Here I briefly review Affect Valuation Theory (AVT), which integrates ideal affect into existing models of affect and emotion by identifying the causes and consequences of variation in ideal affect. I then describe recent research that applies AVT to the valuation of negative states as well as more complex states, examines how ideal affect shapes momentary affective experience, suggests that ideal affect has both direct and indirect effects on health, and illustrates that people's ideal affect shapes how they judge and respond to others. Finally, I discuss the implications of cultural and individual differences in ideal affect for clinical, educational, work, and leisure settings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Deceleration of a supersonic flow behind a curved shock wave with isentropic precompression

NASA Technical Reports Server (NTRS)

Dulov, V. G.; Shchepanovskiy, V. A.

1985-01-01

Three-dimensional supersonic flows of an ideal fluid in the neighborhood of bodies formed by being cut out along the streamlines of an axisymmetric flow are investigated. The flow consists of a region of isoentropic compression and a region of vortex flow. An exact solution with variable entropy is used to describe the flow in the vortex region. In the continuous flow region an approximate solution is constructed by expanding the solution in a series in a small parameter. The effect of the shape of the excision and the vorticity of the flow on compression of the jet and and the total pressure loss coefficient is studied.

Effect of coolant flow ejection on aerodynamic performance of low-aspect-ratio vanes. 2: Performance with coolant flow ejection at temperature ratios up to 2

NASA Technical Reports Server (NTRS)

Hass, J. E.; Kofskey, M. G.

1977-01-01

The aerodynamic performance of a 0.5 aspect ratio turbine vane configuration with coolant flow ejection was experimentally determined in a full annular cascade. The vanes were tested at a nominal mean section ideal critical velocity ratio of 0.890 over a range of primary to coolant total temperature ratio from 1.0 to 2.08 and a range of coolant to primary total pressure ratio from 1.0 to 1.4 which corresponded to coolant flows from 3.0 to 10.7 percent of the primary flow. The variations in primary and thermodynamic efficiency and exit flow conditions with circumferential and radial position were obtained.

Flow in a centrifugal fan impeller at off-design conditions

NASA Astrophysics Data System (ADS)

Wright, T.; Tzou, K. T. S.; Madhavan, S.

1984-06-01

A fully three-dimensional finite element analysis of inviscid, incompressible blade channel flow is the basis of the present study of both predicted and measured surface velocity and pressure distributions in the internal flow channels of a centrifugal fan impeller, for volume flow rates of 80-125 percent the design flow rate. The experimental results made extensive use of blade and sidewall surface pressure taps installed in a scale model of an airfoil-bladed centrifugal fan impeller. The results obtained illustrate the ability of both flow analyses to predict the dominant features of the impeller flow field, including peak blade surface velocities and adverse gradients at flows far from the design point. Insight is also gained into the limiting channel diffusion values for typical centrifugal cascade performance, together with the influence of viscous effects, as seen in deviations from ideal flow predictions.

On the pollutant removal, dispersion, and entrainment over two-dimensional idealized street canyons

NASA Astrophysics Data System (ADS)

Liu, Chun-Ho; Wong, Colman C. C.

2014-01-01

Pollutant dispersion over urban areas is not that well understood, in particular at the street canyon scale. This study is therefore conceived to examine how urban morphology modifies the pollutant removal, dispersion, and entrainment over urban areas. An idealized computational domain consisting of 12 two-dimensional (2D) identical street canyons of unity aspect ratio is employed. The large-eddy simulation (LES) is used to calculate the turbulent flows and pollutant transport in the urban boundary layer (UBL). An area source of uniform pollutant concentration is applied on the ground of the first street canyon. A close examination on the roof-level turbulence reveals patches of low-speed air masses in the streamwise flows and narrow high-speed downdrafts in the shear layer. Different from the flows over a smooth surface, the turbulence intensities are peaked near the top of the building roughness. The pollutant is rather uniformly distributed inside a street canyon but disperses quickly in the UBL over the buildings. Partitioning the vertical pollutant flux into its mean and turbulent components demystifies that the pollutant removal is mainly governed by turbulence. Whereas, mean wind carries pollutant into and out of a street canyon simultaneously. In addition to wind speed promotion, turbulent mixing is thus required to dilute the ground-level pollutants, which are then removed from the street canyon to the UBL. Atmospheric flows slow down rapidly after the leeward buildings, leading to updrafts carrying pollutants away from the street canyons (the basic pollutant removal mechanism).

Cardiorespiratory fitness and ideal cardiovascular health in European adolescents.

PubMed

Ruiz, Jonatan R; Huybrechts, Inge; Cuenca-García, Magdalena; Artero, Enrique G; Labayen, Idoia; Meirhaeghe, Aline; Vicente-Rodriguez, German; Polito, Angela; Manios, Yannis; González-Gross, Marcela; Marcos, Ascensión; Widhalm, Kurt; Molnar, Denes; Kafatos, Anthony; Sjöström, Michael; Moreno, Luis A; Castillo, Manuel J; Ortega, Francisco B

2015-05-15

We studied in European adolescents (i) the association between cardiorespiratory fitness and ideal cardiovascular health as defined by the American Heart Association and (ii) whether there is a cardiorespiratory fitness threshold associated with a more favourable cardiovascular health profile. Participants included 510 (n=259 girls) adolescents from 9 European countries. The 20 m shuttle run test was used to estimate cardiorespiratory fitness. Ideal cardiovascular health was defined as meeting ideal levels of the following components: four behaviours (smoking, body mass index, physical activity and diet) and three factors (total cholesterol, blood pressure and glucose). Higher levels of cardiorespiratory fitness were associated with a higher number of ideal cardiovascular health components in both boys and girls (both p for trend ≤0.001). Levels of cardiorespiratory fitness were significantly higher in adolescents meeting at least four ideal components (13% higher in boys, p<0.001; 6% higher in girls, p=0.008). Receiver operating characteristic curve analyses showed a significant discriminating accuracy of cardiorespiratory fitness in identifying the presence of at least four ideal cardiovascular health components (43.8 mL/kg/min in boys and 34.6 mL/kg/min in girls, both p<0.001). The results suggest a hypothetical cardiorespiratory fitness level associated with a healthier cardiovascular profile in adolescents. The fitness standards could be used in schools as part of surveillance and/or screening systems to identify youth with poor health behaviours who might benefit from intervention programmes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Non-ideal Solution Thermodynamics of Cytoplasm

PubMed Central

Ross-Rodriguez, Lisa U.; McGann, Locksley E.

2012-01-01

Quantitative description of the non-ideal solution thermodynamics of the cytoplasm of a living mammalian cell is critically necessary in mathematical modeling of cryobiology and desiccation and other fields where the passive osmotic response of a cell plays a role. In the solution thermodynamics osmotic virial equation, the quadratic correction to the linear ideal, dilute solution theory is described by the second osmotic virial coefficient. Herein we report, for the first time, intracellular solution second osmotic virial coefficients for four cell types [TF-1 hematopoietic stem cells, human umbilical vein endothelial cells (HUVEC), porcine hepatocytes, and porcine chondrocytes] and further report second osmotic virial coefficients indistinguishable from zero (for the concentration range studied) for human hepatocytes and mouse oocytes. PMID:23840923

Ideal Standards, Acceptance, and Relationship Satisfaction: Latitudes of Differential Effects

PubMed Central

Buyukcan-Tetik, Asuman; Campbell, Lorne; Finkenauer, Catrin; Karremans, Johan C.; Kappen, Gesa

2017-01-01

We examined whether the relations of consistency between ideal standards and perceptions of a current romantic partner with partner acceptance and relationship satisfaction level off, or decelerate, above a threshold. We tested our hypothesis using a 3-year longitudinal data set collected from heterosexual newlywed couples. We used two indicators of consistency: pattern correspondence (within-person correlation between ideal standards and perceived partner ratings) and mean-level match (difference between ideal standards score and perceived partner score). Our results revealed that pattern correspondence had no relation with partner acceptance, but a positive linear/exponential association with relationship satisfaction. Mean-level match had a significant positive association with actor’s acceptance and relationship satisfaction up to the point where perceived partner score equaled ideal standards score. Partner effects did not show a consistent pattern. The results suggest that the consistency between ideal standards and perceived partner attributes has a non-linear association with acceptance and relationship satisfaction, although the results were more conclusive for mean-level match. PMID:29033876

Handgrip Strength and Ideal Cardiovascular Health among Colombian Children and Adolescents.

PubMed

Ramírez-Vélez, Robinson; Tordecilla-Sanders, Alejandra; Correa-Bautista, Jorge Enrique; Peterson, Mark D; Garcia-Hermoso, Antonio

2016-12-01

To evaluate the association between handgrip strength and ideal cardiovascular health (CVH) in Colombian children and adolescents. During the 2014-2015 school years, we examined a cross-sectional component of the FUPRECOL (Association for Muscular Strength with Early Manifestation of Cardiovascular Disease Risk Factors among Colombian Children and Adolescents) study. Participants included 1199 (n = 627 boys) youths from Bogota (Colombia). Handgrip strength was measured with a standard adjustable hand held dynamometer and expressed relative to body mass (handgrip/body mass) and as absolute values in kilograms. Ideal CVH, as defined by the American Heart Association, was determined as meeting ideal levels of the following components: 4 behaviors (smoking status, body mass index, cardiorespiratory fitness, and diet) and 3 factors (total cholesterol, blood pressure, and glucose). Higher levels of handgrip strength (both absolute and relative values) were associated with a higher frequency of ideal CVH metrics in both sexes (P for trend ≤ .001). Also, higher levels of handgrip strength were associated with a greater number of ideal health behaviors (P for trend < .001 in both boys and girls), and with a higher number of ideal health factors in boys (P for trend < .001). Finally, levels of handgrip strength were similar between ideal versus nonideal glucose or total cholesterol groups in girls. Handgrip strength was strongly associated with ideal CVH in Colombian children and adolescents, and thus supports the relevance of early targeted interventions to promote strength adaptation and preservation as part of primordial prevention. Copyright © 2016 Elsevier Inc. All rights reserved.

Chemical Laws, Idealization and Approximation

NASA Astrophysics Data System (ADS)

Tobin, Emma

2013-07-01

This paper examines the notion of laws in chemistry. Vihalemm ( Found Chem 5(1):7-22, 2003) argues that the laws of chemistry are fundamentally the same as the laws of physics they are all ceteris paribus laws which are true "in ideal conditions". In contrast, Scerri (2000) contends that the laws of chemistry are fundamentally different to the laws of physics, because they involve approximations. Christie ( Stud Hist Philos Sci 25:613-629, 1994) and Christie and Christie ( Of minds and molecules. Oxford University Press, New York, pp. 34-50, 2000) agree that the laws of chemistry are operationally different to the laws of physics, but claim that the distinction between exact and approximate laws is too simplistic to taxonomise them. Approximations in chemistry involve diverse kinds of activity and often what counts as a scientific law in chemistry is dictated by the context of its use in scientific practice. This paper addresses the question of what makes chemical laws distinctive independently of the separate question as to how they are related to the laws of physics. From an analysis of some candidate ceteris paribus laws in chemistry, this paper argues that there are two distinct kinds of ceteris paribus laws in chemistry; idealized and approximate chemical laws. Thus, while Christie ( Stud Hist Philos Sci 25:613-629, 1994) and Christie and Christie ( Of minds and molecules. Oxford University Press, New York, pp. 34--50, 2000) are correct to point out that the candidate generalisations in chemistry are diverse and heterogeneous, a distinction between idealizations and approximations can nevertheless be used to successfully taxonomise them.

The ideal imaging AR waveguide

NASA Astrophysics Data System (ADS)

Grey, David J.

2017-06-01

Imaging waveguides are a key development that are helping to create the Augmented Reality revolution. They have the ability to use a small projector as an input and produce a wide field of view, large eyebox, full colour, see-through image with good contrast and resolution. WaveOptics is at the forefront of this AR technology and has developed and demonstrated an approach which is readily scalable. This paper presents our view of the ideal near-to-eye imaging AR waveguide. This will be a single-layer waveguide which can be manufactured in high volume and low cost, and is suitable for small form factor applications and all-day wear. We discuss the requirements of the waveguide for an excellent user experience. When enhanced (AR) viewing is not required, the waveguide should have at least 90% transmission, no distracting artifacts and should accommodate the user's ophthalmic prescription. When enhanced viewing is required, additionally, the waveguide requires excellent imaging performance, this includes resolution to the limit of human acuity, wide field of view, full colour, high luminance uniformity and contrast. Imaging waveguides are afocal designs and hence cannot provide ophthalmic correction. If the user requires this correction then they must wear either contact lenses, prescription spectacles or inserts. The ideal imaging waveguide would need to cope with all of these situations so we believe it must be capable of providing an eyebox at an eye relief suitable for spectacle wear which covers a significant range of population inter-pupillary distances. We describe the current status of our technology and review existing imaging waveguide technologies against the ideal component.

PLUME DISPERSION IN STABLY STRATIFIED FLOWS OVER COMPLEX TERRAIN, PHASE 2

EPA Science Inventory

Laboratory experiments were conducted in a stratified towing tank to investigate plume dispersion in stably stratified flows. First, plume dispersion over an idealized terrain model with a simulated elevated inversion in the atmosphere was investigated. These results were compare...

Charge-Trapping-Induced Non-Ideal Behaviors in Organic Field-Effect Transistors.

PubMed

Un, Hio-Ieng; Cheng, Peng; Lei, Ting; Yang, Chi-Yuan; Wang, Jie-Yu; Pei, Jian

2018-05-01

Organic field-effect transistors (OFETs) with impressively high hole mobilities over 10 cm 2 V -1 s -1 and electron mobilities over 1 cm 2 V -1 s -1 have been reported in the past few years. However, significant non-ideal electrical characteristics, e.g., voltage-dependent mobilities, have been widely observed in both small-molecule and polymer systems. This issue makes the accurate evaluation of the electrical performance impossible and also limits the practical applications of OFETs. Here, a semiconductor-unrelated, charge-trapping-induced non-ideality in OFETs is reported, and a revised model for the non-ideal transfer characteristics is provided. The trapping process can be directly observed using scanning Kelvin probe microscopy. It is found that such trapping-induced non-ideality exists in OFETs with different types of charge carriers (p-type or n-type), different types of dielectric materials (inorganic and organic) that contain different functional groups (OH, NH 2 , COOH, etc.). As fas as it is known, this is the first report for the non-ideal transport behaviors in OFETs caused by semiconductor-independent charge trapping. This work reveals the significant role of dielectric charge trapping in the non-ideal transistor characteristics and also provides guidelines for device engineering toward ideal OFETs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Slippage and boundary layer probed in an almost ideal gas by a nanomechanical oscillator.

PubMed

Defoort, M; Lulla, K J; Crozes, T; Maillet, O; Bourgeois, O; Collin, E

2014-09-26

We measure the interaction between ⁴He gas at 4.2 K and a high-quality nanoelectromechanical string device for its first three symmetric modes (resonating at 2.2, 6.7, and 11 MHz with quality factor Q>0.1×10⁶) over almost 6 orders of magnitude in pressure. This fluid can be viewed as the best experimental implementation of an almost ideal monoatomic and inert gas of which properties are tabulated. The experiment ranges from high pressure where the flow is of laminar Stokes-type presenting slippage down to very low pressures where the flow is molecular. In the molecular regime, when the mean-free path is of the order of the distance between the suspended nanomechanical probe and the bottom of the trench, we resolve for the first time the signature of the boundary (Knudsen) layer onto the measured dissipation. Our results are discussed in the framework of the most recent theories investigating boundary effects in fluids (both analytic approaches and direct simulation Monte Carlo methods).

Impact of sleep restriction versus idealized sleep on emotional experience, reactivity and regulation in healthy adolescents.

PubMed

Reddy, Radhika; Palmer, Cara A; Jackson, Christine; Farris, Samantha G; Alfano, Candice A

2017-08-01

Sleep loss is associated with affective disturbances and disorders; however, there is limited understanding of specific mechanisms underlying these links, especially in adolescence. The current study tested the effects of sleep restriction versus idealized sleep on adolescents' emotional experience, reactivity and regulation (specifically cognitive reappraisal). Following 1 week of sleep monitoring, healthy adolescents (n = 42; ages 13-17 years) were randomized to 1 night of sleep restriction (4 h) or idealized sleep (9.5 h). The following day, adolescents provided self-reports of affect and anxiety and completed a laboratory-based task to assess: (1) emotional reactivity in response to positive, negative, and neutral images from the International Affective Picture System (IAPS); and (2) ability to use cognitive reappraisal to decrease negative emotional responses. Large effects were observed for the adverse impact of sleep restriction on positive affect and anxiety as well as a medium-sized effect for negative affect, compared to the idealized sleep condition. Subjective reactivity to positive and neutral images did not differ between the groups, but a moderate effect was detected for reactivity to negative images whereby sleep-restricted teens reported greater reactivity. Across both sleep conditions, use of cognitive reappraisal down-regulated negative emotion effectively; however, sleep restriction did not impact upon adolescents' ability to use this strategy. These findings add to a growing body of literature demonstrating the deleterious effects of sleep restriction on aspects of emotion and highlight directions for future research in adolescents. © 2016 European Sleep Research Society.

APPA 2011 Conference Highlights

ERIC Educational Resources Information Center

Facilities Manager, 2011

2011-01-01

This article presents highlights of APPA conference that was held on July 16-18, 2011. The highlights feature photos of 2011-2012 board of directors, outgoing senior regional representatives to the board, meritorious service award, APPA fellow, president's recognition and gavel exchange, and diamond business partner award.

Facilitating pictorial comprehension with color highlighting.

PubMed

McDougald, Brannan R; Wogalter, Michael S

2014-09-01

Pictorials can aid in communicating warning information, but viewers may not always correctly comprehend them. Two experiments focused on whether the use of relevant highlighting could benefit pictorial comprehension. A set of warning-related pictorials were manipulated according to three-color highlighting conditions: highlighting areas more relevant to correct comprehension, highlighting areas less relevant to comprehension, and no highlighting. Participants were asked to describe the purpose and meaning of each pictorial presented to them. The findings from both experiments indicate that comprehension of warning pictorials is higher for the relevant highlighting condition than the other two conditions. The highlighting of less relevant areas reduced comprehension compared to no highlighting. Use of appropriately placed highlighting could benefit the design of a complex symbol by pointing out pertinent areas to aid in determining its intended conceptual meaning. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Supersonic Flow of Chemically Reacting Gas-Particle Mixtures. Volume 2: RAMP - A Computer Code for Analysis of Chemically Reacting Gas-Particle Flows

NASA Technical Reports Server (NTRS)

Penny, M. M.; Smith, S. D.; Anderson, P. G.; Sulyma, P. R.; Pearson, M. L.

1976-01-01

A computer program written in conjunction with the numerical solution of the flow of chemically reacting gas-particle mixtures was documented. The solution to the set of governing equations was obtained by utilizing the method of characteristics. The equations cast in characteristic form were shown to be formally the same for ideal, frozen, chemical equilibrium and chemical non-equilibrium reacting gas mixtures. The characteristic directions for the gas-particle system are found to be the conventional gas Mach lines, the gas streamlines and the particle streamlines. The basic mesh construction for the flow solution is along streamlines and normals to the streamlines for axisymmetric or two-dimensional flow. The analysis gives detailed information of the supersonic flow and provides for a continuous solution of the nozzle and exhaust plume flow fields. Boundary conditions for the flow solution are either the nozzle wall or the exhaust plume boundary.

The place of the ideal observer in medical ethics.

PubMed

Churchill, L R

1983-01-01

The idea of an ideal observer is frequently employed in ethical reasoning and has recently been introduced into medical ethics. The contemporary use of this idea, however, is deeply flawed. It ignores important social and personal dimensions of ethics. By espousing a perspective of observation removed from history and community, the ideal observer notion encourages a pretense of objectivity and overlooks the distortions of distance. If taken seriously as a model for choice, the ideal observer is incoherent, as it dispenses with the concrete moral agent and the locus of choice. Adam Smith's 'impartial spectator' is examined as a more adequate statement of the need for appreciating diverse perspectives in ethical choices.

The energy density distribution of an ideal gas and Bernoulli’s equations

NASA Astrophysics Data System (ADS)

Santos, Leonardo S. F.

2018-05-01

This work discusses the energy density distribution in an ideal gas and the consequences of Bernoulli’s equation and the corresponding relation for compressible fluids. The aim of this work is to study how Bernoulli’s equation determines the energy flow in a fluid, although Bernoulli’s equation does not describe the energy density itself. The model from molecular dynamic considerations that describes an ideal gas at rest with uniform density is modified to explore the gas in motion with non-uniform density and gravitational effects. The difference between the component of the speed of a particle that is parallel to the gas speed and the gas speed itself is called ‘parallel random speed’. The pressure from the ‘parallel random speed’ is denominated as parallel pressure. The modified model predicts that the energy density is the sum of kinetic and potential gravitational energy densities plus two terms with static and parallel pressures. The application of Bernoulli’s equation and the corresponding relation for compressible fluids in the energy density expression has resulted in two new formulations. For incompressible and compressible gas, the energy density expressions are written as a function of stagnation, static and parallel pressures, without any dependence on kinetic or gravitational potential energy densities. These expressions of the energy density are the main contributions of this work. When the parallel pressure was uniform, the energy density distribution for incompressible approximation and compressible gas did not converge to zero for the limit of null static pressure. This result is rather unusual because the temperature tends to zero for null pressure. When the gas was considered incompressible and the parallel pressure was equal to static pressure, the energy density maintained this unusual behaviour with small pressures. If the parallel pressure was equal to static pressure, the energy density converged to zero for the limit of the

Quantifying ataxia: ideal trajectory analysis--a technical note

NASA Technical Reports Server (NTRS)

McPartland, M. D.; Krebs, D. E.; Wall, C. 3rd

2000-01-01

We describe a quantitative method to assess repeated stair stepping stability. In both the mediolateral (ML) and anterioposterior (AP) directions, the trajectory of the subject's center of mass (COM) was compared to an ideal sinusoid. The two identified sinusoids were unique in each direction but coupled. Two dimensionless numbers-the mediolateral instability index (IML) and AP instability index (IAP)-were calculated using the COM trajectory and ideal sinusoids for each subject with larger index values resulting from less stable performance. The COM trajectories of nine nonimpaired controls and six patients diagnosed with unilateral or bilateral vestibular labyrinth hypofunction were analyzed. The average IML and IAP values of labyrinth disorder patients were respectively 127% and 119% greater than those of controls (p<0.014 and 0.006, respectively), indicating that the ideal trajectory analysis distinguishes persons with labyrinth disorder from those without. The COM trajectories also identify movement inefficiencies attributable to vestibulopathy.

An Ideal Remedial Reading Program.

ERIC Educational Resources Information Center

Boettcher, Judith A.

An ideal secondary level remedial reading program would be based on the philosophy that both freedom and structure are required, that learning demands involvement and feedback, and that success breeds success. Such programs should be structured (i.e., based on clearly defined content and a clearly designated mode of presentation). There are many…

A Unified Theory of Non-Ideal Gas Lattice Boltzmann Models

NASA Technical Reports Server (NTRS)

Luo, Li-Shi

1998-01-01

A non-ideal gas lattice Boltzmann model is directly derived, in an a priori fashion, from the Enskog equation for dense gases. The model is rigorously obtained by a systematic procedure to discretize the Enskog equation (in the presence of an external force) in both phase space and time. The lattice Boltzmann model derived here is thermodynamically consistent and is free of the defects which exist in previous lattice Boltzmann models for non-ideal gases. The existing lattice Boltzmann models for non-ideal gases are analyzed and compared with the model derived here.

Quantum Max-flow/Min-cut

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, Shawn X., E-mail: xingshan@math.ucsb.edu; Quantum Architectures and Computation Group, Microsoft Research, Redmond, Washington 98052; Freedman, Michael H., E-mail: michaelf@microsoft.com

2016-06-15

The classical max-flow min-cut theorem describes transport through certain idealized classical networks. We consider the quantum analog for tensor networks. By associating an integral capacity to each edge and a tensor to each vertex in a flow network, we can also interpret it as a tensor network and, more specifically, as a linear map from the input space to the output space. The quantum max-flow is defined to be the maximal rank of this linear map over all choices of tensors. The quantum min-cut is defined to be the minimum product of the capacities of edges over all cuts ofmore » the tensor network. We show that unlike the classical case, the quantum max-flow=min-cut conjecture is not true in general. Under certain conditions, e.g., when the capacity on each edge is some power of a fixed integer, the quantum max-flow is proved to equal the quantum min-cut. However, concrete examples are also provided where the equality does not hold. We also found connections of quantum max-flow/min-cut with entropy of entanglement and the quantum satisfiability problem. We speculate that the phenomena revealed may be of interest both in spin systems in condensed matter and in quantum gravity.« less

Quantum Max-flow/Min-cut

NASA Astrophysics Data System (ADS)

Cui, Shawn X.; Freedman, Michael H.; Sattath, Or; Stong, Richard; Minton, Greg

2016-06-01

The classical max-flow min-cut theorem describes transport through certain idealized classical networks. We consider the quantum analog for tensor networks. By associating an integral capacity to each edge and a tensor to each vertex in a flow network, we can also interpret it as a tensor network and, more specifically, as a linear map from the input space to the output space. The quantum max-flow is defined to be the maximal rank of this linear map over all choices of tensors. The quantum min-cut is defined to be the minimum product of the capacities of edges over all cuts of the tensor network. We show that unlike the classical case, the quantum max-flow=min-cut conjecture is not true in general. Under certain conditions, e.g., when the capacity on each edge is some power of a fixed integer, the quantum max-flow is proved to equal the quantum min-cut. However, concrete examples are also provided where the equality does not hold. We also found connections of quantum max-flow/min-cut with entropy of entanglement and the quantum satisfiability problem. We speculate that the phenomena revealed may be of interest both in spin systems in condensed matter and in quantum gravity.

Plasmoids everywhere: ideal tearing, the transition to fast reconnection, and solar activity.

NASA Astrophysics Data System (ADS)

Velli, M. C. M.; Pucci, F.; Tenerani, A.; Shi, C.; Del Sarto, D.; Rappazzo, A. F.

2017-12-01

We discuss the role of generalized ``ideal" tearing (IT) as a possible trigger mechanism for magnetic reconnection to understand energetic phenomena in the solar atmosphere. We begin with a pedagogical introduction to the IT concept, how it stems from the classical analysis of the tearing instability, what is meant by plasmoids, and the connections of IT to the plasmoid instability and Sweet Parker current sheets. We then proceed to analyze how the IT concept extends to equilibria with flows, small scale kinetic effects, different current structures and different magnetic field topology configurations. Finally we discuss the relationship of reconnection triggering to nonlinear cascades and turbulent evolution, and how different situations may arise depending on scale, boundary conditions, and time-history, from coronal heating via nanoflares, to solar flares and coronal mass ejections. Issues of local topology, dimensionality, anisotropy will also be discussed.

Architected squirt-flow materials for energy dissipation

NASA Astrophysics Data System (ADS)

Cohen, Tal; Kurzeja, Patrick; Bertoldi, Katia

2017-12-01

In the present study we explore material architectures that lead to enhanced dissipation properties by taking advantage of squirt-flow - a local flow mechanism triggered by heterogeneities at the pore level. While squirt-flow is a known dominant source of dissipation and seismic attenuation in fluid saturated geological materials, we study its untapped potential to be incorporated in highly deformable elastic materials with embedded fluid-filled cavities for future engineering applications. An analytical investigation, that isolates the squirt-flow mechanism from other potential dissipation mechanisms and considers an idealized setting, predicts high theoretical levels of dissipation achievable by squirt-flow and establishes a set of guidelines for optimal dissipation design. Particular architectures are then investigated via numerical simulations showing that a careful design of the internal voids can lead to an increase of dissipation levels by an order of magnitude, compared with equivalent homogeneous void distributions. Therefore, we suggest squirt-flow as a promising mechanism to be incorporated in future architected materials to effectively and reversibly dissipate energy.

Chemical Laws, Idealization and Approximation

ERIC Educational Resources Information Center

Tobin, Emma

2013-01-01

This paper examines the notion of laws in chemistry. Vihalemm ("Found Chem" 5(1):7-22, 2003) argues that the laws of chemistry are fundamentally the same as the laws of physics they are all "ceteris paribus" laws which are true "in ideal conditions". In contrast, Scerri (2000) contends that the laws of chemistry are…

A theoretical study on hot charge-transfer states and dimensional effects of organic photocells based on an ideal diode model.

PubMed

Shimazaki, Tomomi; Nakajima, Takahito

2017-05-21

This paper discusses an ideal diode model with hot charge-transfer (CT) states to analyze the power conversion efficiency of an organic photocell. A free carrier generation mechanism via sunlight in an organic photocell consists of four microscopic processes: photon absorption, exciton dissociation, CT, and charge separation. The hot CT state effect has been actively investigated to understand the charge separation process. We previously reported a theoretical method to calculate the efficiency of the charge separation process via a hot CT state (T. Shimazaki et al., Phys. Chem. Chem. Phys., 2015, 17, 12538 and J. Chem. Phys., 2016, 144, 234906). In this paper, we integrate the simulation method into the ideal photocell diode model and calculate several properties such as short circuit current, open circuit voltage, and power conversion efficiency. Our results highlight that utilizing the dimensional (entropy) effect together with the hot CT state can play an essential role in developing more efficient organic photocell devices.

Membranes for redox flow battery applications.

PubMed

Prifti, Helen; Parasuraman, Aishwarya; Winardi, Suminto; Lim, Tuti Mariana; Skyllas-Kazacos, Maria

2012-06-19

The need for large scale energy storage has become a priority to integrate renewable energy sources into the electricity grid. Redox flow batteries are considered the best option to store electricity from medium to large scale applications. However, the current high cost of redox flow batteries impedes the wide spread adoption of this technology. The membrane is a critical component of redox flow batteries as it determines the performance as well as the economic viability of the batteries. The membrane acts as a separator to prevent cross-mixing of the positive and negative electrolytes, while still allowing the transport of ions to complete the circuit during the passage of current. An ideal membrane should have high ionic conductivity, low water intake and excellent chemical and thermal stability as well as good ionic exchange capacity. Developing a low cost, chemically stable membrane for redox flow cell batteries has been a major focus for many groups around the world in recent years. This paper reviews the research work on membranes for redox flow batteries, in particular for the all-vanadium redox flow battery which has received the most attention.

Membranes for Redox Flow Battery Applications

PubMed Central

Prifti, Helen; Parasuraman, Aishwarya; Winardi, Suminto; Lim, Tuti Mariana; Skyllas-Kazacos, Maria

2012-01-01

The need for large scale energy storage has become a priority to integrate renewable energy sources into the electricity grid. Redox flow batteries are considered the best option to store electricity from medium to large scale applications. However, the current high cost of redox flow batteries impedes the wide spread adoption of this technology. The membrane is a critical component of redox flow batteries as it determines the performance as well as the economic viability of the batteries. The membrane acts as a separator to prevent cross-mixing of the positive and negative electrolytes, while still allowing the transport of ions to complete the circuit during the passage of current. An ideal membrane should have high ionic conductivity, low water intake and excellent chemical and thermal stability as well as good ionic exchange capacity. Developing a low cost, chemically stable membrane for redox flow cell batteries has been a major focus for many groups around the world in recent years. This paper reviews the research work on membranes for redox flow batteries, in particular for the all-vanadium redox flow battery which has received the most attention. PMID:24958177

Delivering ideal employee experiences.

PubMed

Weiss, Marjorie D; Tyink, Steve; Kubiak, Curt

2009-05-01

Employee-centric strategies have moved from employee satisfaction and brand awareness to employee "affinity" or "attachment." In today's marketplace, occupational health nurses understand that differentiation (i.e., the perception of uniqueness) is the direct result of superior employee interactions, which lead to better employee care, enduring employee relationships, loyal employees, and satisfied employers. What drives employees to occupational health nurse attachment? The answer is a passion for rising above the competition to create ideal employee experiences.

Robotic kidney transplantation with regional hypothermia: evolution of a novel procedure utilizing the IDEAL guidelines (IDEAL phase 0 and 1).

PubMed

Menon, Mani; Abaza, Ronney; Sood, Akshay; Ahlawat, Rajesh; Ghani, Khurshid R; Jeong, Wooju; Kher, Vijay; Kumar, Ramesh K; Bhandari, Mahendra

2014-05-01

Surgical innovation is essential for progress of surgical science, but its implementation comes with potential harms during the learning phase. The Balliol Collaboration has recommended a set of guidelines (Innovation, Development, Exploration, Assessment, Long-term study [IDEAL]) that permit innovation while minimizing complications. To utilize the IDEAL model of surgical innovation in the development of a novel surgical technique, robotic kidney transplantation (RKT) with regional hypothermia, and describe the process of discovery and development. Phase 0 (simulation) studies included the establishment of techniques for pelvic cooling, graft placement in a robotic prostatectomy model, and simulation of the RKT procedure in a cadaveric model. Phase 1 (innovation) studies began in January 2013 and involved treatment of a highly selective small group of patients (n=7), using the principles utilized in the phase 0 studies, at a tertiary referral center. IDEAL model implementation in the development of RKT with regional hypothermia. For phase 0 studies, the outcomes evaluated included pelvic and body temperature measurements, and technical feasibility assessment. The primary outcome during phase 1 was post-transplant graft function. Other outcomes measured were operative and ischemic times, perioperative complications, and intracorporeal graft surface temperature. Phase 0 (simulation phase): Pelvic cooling to 15-20(o)C was achieved reproducibly. Using the surgical approach developed for robotic radical prostatectomy, vascular and ureterovesical anastomoses could be done without redocking the robot. Phase 1 (innovation phase): All patients underwent live-donor RKT in the lithotomy position. All grafts functioned immediately. Mean console, anastomotic, and warm ischemia times were 154 min, 29 min, and 2 min, respectively. One patient was re-explored on postoperative day 1. Adherence to the IDEAL guidelines put forth by the Balliol Collaboration provided a practical

Imaging flow cytometry for phytoplankton analysis.

PubMed

Dashkova, Veronika; Malashenkov, Dmitry; Poulton, Nicole; Vorobjev, Ivan; Barteneva, Natasha S

2017-01-01

This review highlights the concepts and instrumentation of imaging flow cytometry technology and in particular its use for phytoplankton analysis. Imaging flow cytometry, a hybrid technology combining speed and statistical capabilities of flow cytometry with imaging features of microscopy, is rapidly advancing as a cell imaging platform that overcomes many of the limitations of current techniques and contributed significantly to the advancement of phytoplankton analysis in recent years. This review presents the various instrumentation relevant to the field and currently used for assessment of complex phytoplankton communities' composition and abundance, size structure determination, biovolume estimation, detection of harmful algal bloom species, evaluation of viability and metabolic activity and other applications. Also we present our data on viability and metabolic assessment of Aphanizomenon sp. cyanobacteria using Imagestream X Mark II imaging cytometer. Herein, we highlight the immense potential of imaging flow cytometry for microalgal research, but also discuss limitations and future developments. Copyright © 2016 Elsevier Inc. All rights reserved.

Sharp Truncation of an Electric Field: An Idealized Model That Warrants Caution

ERIC Educational Resources Information Center

Tu, Hong; Zhu, Jiongming

2016-01-01

In physics, idealized models are often used to simplify complex situations. The motivation of the idealization is to make the real complex system tractable by adopting certain simplifications. In this treatment some unnecessary, negligible aspects are stripped away (so-called Aristotelian idealization), or some deliberate distortions are involved…

Caste and Choice: The Influence of Developmental Idealism on Marriage Behavior

PubMed Central

Allendorf, Keera; Thornton, Arland

2015-01-01

Is young people’s marriage behavior determined by their socioeconomic characteristics or their endorsement of developmental idealism? This article addresses this question using a unique, longitudinal data set from Nepal and provides the first individual-level test of developmental idealism theory. We find that unmarried individuals with greater endorsement of developmental idealism in 2008 were more likely by 2012 to choose their own spouse, including a spouse of a different caste, rather than have an arranged marriage. Those with salaried work experience were also less likely to have arranged marriages, but urban proximity and education were not significant. We conclude that both developmental idealism and socioeconomic characteristics influence marriage and their influences are largely independent. PMID:26430712

Neurocultural evidence that ideal affect match promotes giving

PubMed Central

Park, BoKyung; Blevins, Elizabeth; Knutson, Brian

2017-01-01

Abstract Why do people give to strangers? We propose that people trust and give more to those whose emotional expressions match how they ideally want to feel (“ideal affect match”). European Americans and Koreans played multiple trials of the Dictator Game with recipients who varied in emotional expression (excited, calm), race (White, Asian) and sex (male, female). Consistent with their culture’s valued affect, European Americans trusted and gave more to excited than calm recipients, whereas Koreans trusted and gave more to calm than excited recipients. These findings held regardless of recipient race and sex. We then used fMRI to probe potential affective and mentalizing mechanisms. Increased activity in the nucleus accumbens (associated with reward anticipation) predicted giving, as did decreased activity in the right temporo-parietal junction (rTPJ; associated with reduced belief prediction error). Ideal affect match decreased rTPJ activity, suggesting that people may trust and give more to strangers whom they perceive to share their affective values. PMID:28379542

Reported Effects of Masculine Ideals on Gay Men.

PubMed

Sánchez, Francisco J; Greenberg, Stefanie T; Liu, William Ming; Vilain, Eric

2009-01-01

This exploratory study used consensual qualitative research methodology (Hill et al., 2005) to analyze what gay men associate with masculinity and femininity, how they feel masculine ideals affect their self-image, and how masculine ideals affect their same-sex relationships. Written responses were collected from 547 self-identified gay men in the U.S. via an Internet-based survey. Findings supported previous reports that perceptions of gender roles among gay men appear based on masculine and feminine stereotypes. Additionally, more adverse versus positive effects on self-image and same-sex romantic relationships were reported including difficulty being emotional and affectionate, pressure to be physically attractive, and pressure to appear masculine in order to be accepted by society and to be seen as desirable by other gay men. While research on gay men's experience with masculinity continues, psychologists should consider the possible influence of traditional masculine ideals when conceptualizing their gay male clients.

Reported Effects of Masculine Ideals on Gay Men

PubMed Central

Sánchez, Francisco J.; Greenberg, Stefanie T.; Liu, William Ming; Vilain, Eric

2010-01-01

This exploratory study used consensual qualitative research methodology (Hill et al., 2005) to analyze what gay men associate with masculinity and femininity, how they feel masculine ideals affect their self-image, and how masculine ideals affect their same-sex relationships. Written responses were collected from 547 self-identified gay men in the U.S. via an Internet-based survey. Findings supported previous reports that perceptions of gender roles among gay men appear based on masculine and feminine stereotypes. Additionally, more adverse versus positive effects on self-image and same-sex romantic relationships were reported including difficulty being emotional and affectionate, pressure to be physically attractive, and pressure to appear masculine in order to be accepted by society and to be seen as desirable by other gay men. While research on gay men’s experience with masculinity continues, psychologists should consider the possible influence of traditional masculine ideals when conceptualizing their gay male clients. PMID:20628534

Structural arrest in an ideal gas.

PubMed

van Ketel, Willem; Das, Chinmay; Frenkel, Daan

2005-04-08

We report a molecular dynamics study of a simple model system that has the static properties of an ideal gas, yet exhibits nontrivial "glassy" dynamics behavior at high densities. The constituent molecules of this system are constructs of three infinitely thin hard rods of length L, rigidly joined at their midpoints. The crosses have random but fixed orientation. The static properties of this system are those of an ideal gas, and its collision frequency can be computed analytically. For number densities NL(3)/V>1, the single-particle diffusivity goes to zero. As the system is completely structureless, standard mode-coupling theory cannot describe the observed structural arrest. Nevertheless, the system exhibits many dynamical features that appear to be mode-coupling-like. All high-density incoherent intermediate scattering functions collapse onto master curves that depend only on the wave vector.

Tempting Fate or Inviting Happiness? Unrealistic idealization prevents the decline of marital satisfaction

PubMed Central

Murray, Sandra L.; Griffin, Dale W.; Derrick, Jaye L.; Harris, Brianna; Aloni, Maya; Leder, Sadie

2014-01-01

The authors examine whether unrealistically viewing a romantic partner as the image of one’s ideal partner accelerates or slows declines in marital satisfaction among newlyweds. A longitudinal study linked unrealistic idealization at the point of marriage to changes in satisfaction over the first three years of marriage. Overall, satisfaction declined markedly, consistent with past research. However, seeing a less-than-ideal partner as a reflection of one’s ideals predicted a certain level of immunity to the corrosive effects of time: People who initially idealized their partner highly experienced no declines in satisfaction. The obtained benefits of idealization remained in analyses that separately controlled for the positivity of partner perceptions and the possibility that better adjusted people might be in better relationships. PMID:21467549

Critical Thinking and Educational Ideal

ERIC Educational Resources Information Center

Liu, Qian

2007-01-01

Critical thinking, as an educational trend, has been much discussed and proposed nowadays. In this paper, an analysis is made on the gap between our present educational practice and educational ideal from three different aspects, that is, the content, the manner and the one-sidedness of our teaching. It's observed that there is still a long way to…

Uncertainty in counting ice nucleating particles with continuous flow diffusion chambers

DOE PAGES

Garimella, Sarvesh; Rothenberg, Daniel A.; Wolf, Martin J.; ...

2017-09-14

This study investigates the measurement of ice nucleating particle (INP) concentrations and sizing of crystals using continuous flow diffusion chambers (CFDCs). CFDCs have been deployed for decades to measure the formation of INPs under controlled humidity and temperature conditions in laboratory studies and by ambient aerosol populations. These measurements have, in turn, been used to construct parameterizations for use in models by relating the formation of ice crystals to state variables such as temperature and humidity as well as aerosol particle properties such as composition and number. We show here that assumptions of ideal instrument behavior are not supported by measurements mademore » with a commercially available CFDC, the SPectrometer for Ice Nucleation (SPIN), and the instrument on which it is based, the Zurich Ice Nucleation Chamber (ZINC). Non-ideal instrument behavior, which is likely inherent to varying degrees in all CFDCs, is caused by exposure of particles to different humidities and/or temperatures than predicated from instrument theory of operation. This can result in a systematic, and variable, underestimation of reported INP concentrations. Here we find here variable correction factors from 1.5 to 9.5, consistent with previous literature values. We use a machine learning approach to show that non-ideality is most likely due to small-scale flow features where the aerosols are combined with sheath flows. Machine learning is also used to minimize the uncertainty in measured INP concentrations. Finally, we suggest that detailed measurement, on an instrument-by-instrument basis, be performed to characterize this uncertainty.« less

Uncertainty in counting ice nucleating particles with continuous flow diffusion chambers

NASA Astrophysics Data System (ADS)

Garimella, Sarvesh; Rothenberg, Daniel A.; Wolf, Martin J.; David, Robert O.; Kanji, Zamin A.; Wang, Chien; Rösch, Michael; Cziczo, Daniel J.

2017-09-01

This study investigates the measurement of ice nucleating particle (INP) concentrations and sizing of crystals using continuous flow diffusion chambers (CFDCs). CFDCs have been deployed for decades to measure the formation of INPs under controlled humidity and temperature conditions in laboratory studies and by ambient aerosol populations. These measurements have, in turn, been used to construct parameterizations for use in models by relating the formation of ice crystals to state variables such as temperature and humidity as well as aerosol particle properties such as composition and number. We show here that assumptions of ideal instrument behavior are not supported by measurements made with a commercially available CFDC, the SPectrometer for Ice Nucleation (SPIN), and the instrument on which it is based, the Zurich Ice Nucleation Chamber (ZINC). Non-ideal instrument behavior, which is likely inherent to varying degrees in all CFDCs, is caused by exposure of particles to different humidities and/or temperatures than predicated from instrument theory of operation. This can result in a systematic, and variable, underestimation of reported INP concentrations. We find here variable correction factors from 1.5 to 9.5, consistent with previous literature values. We use a machine learning approach to show that non-ideality is most likely due to small-scale flow features where the aerosols are combined with sheath flows. Machine learning is also used to minimize the uncertainty in measured INP concentrations. We suggest that detailed measurement, on an instrument-by-instrument basis, be performed to characterize this uncertainty.

Turboprop IDEAL: a motion-resistant fat-water separation technique.

PubMed

Huo, Donglai; Li, Zhiqiang; Aboussouan, Eric; Karis, John P; Pipe, James G

2009-01-01

Suppression of the fat signal in MRI is very important for many clinical applications. Multi-point water-fat separation methods, such as IDEAL (Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation), can robustly separate water and fat signal, but inevitably increase scan time, making separated images more easily affected by patient motions. PROPELLER (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction) and Turboprop techniques offer an effective approach to correct for motion artifacts. By combining these techniques together, we demonstrate that the new TP-IDEAL method can provide reliable water-fat separation with robust motion correction. The Turboprop sequence was modified to acquire source images, and motion correction algorithms were adjusted to assure the registration between different echo images. Theoretical calculations were performed to predict the optimal shift and spacing of the gradient echoes. Phantom images were acquired, and results were compared with regular FSE-IDEAL. Both T1- and T2-weighted images of the human brain were used to demonstrate the effectiveness of motion correction. TP-IDEAL images were also acquired for pelvis, knee, and foot, showing great potential of this technique for general clinical applications.

Hybrid normed ideal perturbations of n-tuples of operators I

NASA Astrophysics Data System (ADS)

Voiculescu, Dan-Virgil

2018-06-01

In hybrid normed ideal perturbations of n-tuples of operators, the normed ideal is allowed to vary with the component operators. We begin extending to this setting the machinery we developed for normed ideal perturbations based on the modulus of quasicentral approximation and an adaptation of our non-commutative generalization of the Weyl-von Neumann theorem. For commuting n-tuples of hermitian operators, the modulus of quasicentral approximation remains essentially the same when Cn- is replaced by a hybrid n-tuple Cp1,…- , … , Cpn- , p1-1 + ⋯ + pn-1 = 1. The proof involves singular integrals of mixed homogeneity.

Health care market deviations from the ideal market.

PubMed

Mwachofi, Ari; Al-Assaf, Assaf F

2011-08-01

A common argument in the health policy debate is that market forces allocate resources efficiently in health care, and that government intervention distorts such allocation. Rarely do those making such claims state explicitly that the market they refer to is an ideal in economic theory which can only exist under very strict conditions. This paper explores the strict conditions necessary for that ideal market in the context of health care as a means of examining the claim that market forces do allocate resources efficiently in health care.

Idealness and similarity in goal-derived categories: a computational examination.

PubMed

Voorspoels, Wouter; Storms, Gert; Vanpaemel, Wolf

2013-02-01

The finding that the typicality gradient in goal-derived categories is mainly driven by ideals rather than by exemplar similarity has stood uncontested for nearly three decades. Due to the rather rigid earlier implementations of similarity, a key question has remained--that is, whether a more flexible approach to similarity would alter the conclusions. In the present study, we evaluated whether a similarity-based approach that allows for dimensional weighting could account for findings in goal-derived categories. To this end, we compared a computational model of exemplar similarity (the generalized context model; Nosofsky, Journal of Experimental Psychology. General 115:39-57, 1986) and a computational model of ideal representation (the ideal-dimension model; Voorspoels, Vanpaemel, & Storms, Psychonomic Bulletin & Review 18:1006-114, 2011) in their accounts of exemplar typicality in ten goal-derived categories. In terms of both goodness-of-fit and generalizability, we found strong evidence for an ideal approach in nearly all categories. We conclude that focusing on a limited set of features is necessary but not sufficient to account for the observed typicality gradient. A second aspect of ideal representations--that is, that extreme rather than common, central-tendency values drive typicality--seems to be crucial.

Umbilical hernia repair with mesh: identifying effectors of ideal outcomes.

PubMed

Colavita, Paul D; Belyansky, Igor; Walters, Amanda L; Zemlyak, Alla Y; Lincourt, Amy E; Heniford, B Todd; Augenstein, Vedra A

2014-09-01

Quality of life has become an important focus for improvement in hernia repair. The International Hernia Mesh Registry was queried. The Carolinas Comfort Scale quantitated quality of life at 1-month, 6-month, and annual follow-up. Scores of 0 (completely asymptomatic) in all categories without recurrence defined an ideal outcome. The analysis consisted of 363 umbilical hernia repairs; 18.7% were laparoscopic. Demographics included age of 51.5 ± 13.8 years, 24.5% were female, and the average body mass index was 30.63 ± 5.9 kg/m(2). Mean defect size was 4.3 ± 3.1 cm(2). Mean follow-up was 18.2 months. Absent/minimal preoperative symptoms were predictive of ideal outcome at all time points and increasing age was predictive at 6 months and 1 year. At 6 months, the use of fixation sutures alone versus tacks (odds ratio 14.1) predicted ideal outcome. Ideal outcomes are dependent on both patient-specific and operative factors. The durable, ideal outcome in umbilical hernia repair is most likely in an older, asymptomatic patient who undergoes mesh fixation with permanent suture. Copyright © 2014 Elsevier Inc. All rights reserved.

Personality traits and appearance-ideal internalization: Differential associations with body dissatisfaction and compulsive exercise.

PubMed

Martin, Shelby J; Racine, Sarah E

2017-12-01

Thin-ideal internalization is a robust risk factor for body dissatisfaction and eating pathology. Conversely, athletic-ideal internalization is often unrelated to body dissatisfaction, but predicts compulsive exercise (i.e., rigid, rule-driven exercise that is continued despite adverse consequences). Distinct personality traits could relate to internalization of different appearance ideals, which may be associated with divergent eating disorder outcomes. Past research has shown that neuroticism is related to body dissatisfaction, whereas extraversion and conscientiousness have been associated with regular and problematic exercise. The current study examined associations among personality traits (i.e., neuroticism, extraversion, conscientiousness), appearance-ideal internalization (i.e., thin- and athletic-ideal), and eating disorder cognitions/behaviors (i.e., body dissatisfaction, compulsive exercise) among 531 college men and women. Moreover, we tested whether appearance-ideal internalization mediated the relationships between personality traits with body dissatisfaction and compulsive exercise. As expected, body dissatisfaction was positively related to neuroticism, and compulsive exercise was positively associated with extraversion. Thin-ideal internalization positively correlated with neuroticism, athletic-ideal internalization positively correlated with conscientiousness, and both thin- and athletic-ideal internalization were positively related to extraversion. After controlling for gender, body mass index, the other appearance-ideal internalization, and the remaining personality traits, the indirect effects of both neuroticism and extraversion on body dissatisfaction through thin-ideal internalization were significant. Extraversion and conscientiousness were indirectly related to compulsive exercise through athletic-ideal internalization, whereas the indirect effect of neuroticism was dependent on covariates. As such, personality traits may be related to

The effect of in-plane arterial curvature on blood flow and oxygen transport in arterio-venous fistulae

NASA Astrophysics Data System (ADS)

Iori, F.; Grechy, L.; Corbett, R. W.; Gedroyc, W.; Duncan, N.; Caro, C. G.; Vincent, P. E.

2015-03-01

Arterio-Venous Fistulae (AVF) are the preferred method of vascular access for patients with end stage renal disease who need hemodialysis. In this study, simulations of blood flow and oxygen transport were undertaken in various idealized AVF configurations. The objective of the study was to understand how arterial curvature affects blood flow and oxygen transport patterns within AVF, with a focus on how curvature alters metrics known to correlate with vascular pathology such as Intimal Hyperplasia (IH). If one subscribes to the hypothesis that unsteady flow causes IH within AVF, then the results suggest that in order to avoid IH, AVF should be formed via a vein graft onto the outer-curvature of a curved artery. However, if one subscribes to the hypothesis that low wall shear stress and/or low lumen-to-wall oxygen flux (leading to wall hypoxia) cause IH within AVF, then the results suggest that in order to avoid IH, AVF should be formed via a vein graft onto a straight artery, or the inner-curvature of a curved artery. We note that the recommendations are incompatible—highlighting the importance of ascertaining the exact mechanisms underlying development of IH in AVF. Nonetheless, the results clearly illustrate the important role played by arterial curvature in determining AVF hemodynamics, which to our knowledge has been overlooked in all previous studies.

Subsonic Flows through S-Ducts with Flow Control

NASA Astrophysics Data System (ADS)

Chen, Yi

An inlet duct of an aircraft connects the air intake mounted on the fuselage to the engine within the aircraft body. The ideal outflow quality of the duct is steady, uniform and of high total pressure. Recently compact S-shaped inlet ducts are drawing more attention in the design of UAVs with short propulsion system. Compact ducts usually involve strong streamwise adverse pressure gradient and transverse secondary flow, leading to large-scale harmful vortical structures in the outflow. To improve the outflow quality modern flow control techniques have to be applied. Before designing successful flow control methods a solid understanding of the baseline flow field with the duct is crucial. In this work the fundamental mechanism of how the three dimensional flow topology evolves when the relevant parameters such as the duct geometry and boundary layer thickness are varied, is studied carefully. Two distinct secondary-flow patterns are identified. For the first time the sensitivity of the flow topology to the inflow boundary layer thickness in long ducts is clearly addressed. The interaction between the transverse motion induced by the transverse pressure gradient and the streamwise separation is revealed as the crucial reason for the various flow patterns existing in short ducts. A non-symmetric flow pattern is identified for the first time in both experiments and simulations in short ducts in which the intensity of the streamwise separation and the transverse invasion are in the same order of magnitude. A theory of energy accumulation and solution bifurcation is used to give a reasonable explanation for this non-symmetry. After gaining the knowledge of where and how the harmful vortical structures are generated several flow control techniques are tested to achieve a better outflow quality. The analysis of the flow control cases also provides a deeper insight into the behavior of the three-dimensional flow within the ducts. The conventional separation control method

Nonlinear Dynamics of Non-uniform Current-Vortex Sheets in Magnetohydrodynamic Flows

NASA Astrophysics Data System (ADS)

Matsuoka, C.; Nishihara, K.; Sano, T.

2017-04-01

A theoretical model is proposed to describe fully nonlinear dynamics of interfaces in two-dimensional MHD flows based on an idea of non-uniform current-vortex sheet. Application of vortex sheet model to MHD flows has a crucial difficulty because of non-conservative nature of magnetic tension. However, it is shown that when a magnetic field is initially parallel to an interface, the concept of vortex sheet can be extended to MHD flows (current-vortex sheet). Two-dimensional MHD flows are then described only by a one-dimensional Lagrange parameter on the sheet. It is also shown that bulk magnetic field and velocity can be calculated from their values on the sheet. The model is tested by MHD Richtmyer-Meshkov instability with sinusoidal vortex sheet strength. Two-dimensional ideal MHD simulations show that the nonlinear dynamics of a shocked interface with density stratification agrees fairly well with that for its corresponding potential flow. Numerical solutions of the model reproduce properly the results of the ideal MHD simulations, such as the roll-up of spike, exponential growth of magnetic field, and its saturation and oscillation. Nonlinear evolution of the interface is found to be determined by the Alfvén and Atwood numbers. Some of their dependence on the sheet dynamics and magnetic field amplification are discussed. It is shown by the model that the magnetic field amplification occurs locally associated with the nonlinear dynamics of the current-vortex sheet. We expect that our model can be applicable to a wide variety of MHD shear flows.

Ideal GLM-MHD: About the entropy consistent nine-wave magnetic field divergence diminishing ideal magnetohydrodynamics equations

NASA Astrophysics Data System (ADS)

Derigs, Dominik; Winters, Andrew R.; Gassner, Gregor J.; Walch, Stefanie; Bohm, Marvin

2018-07-01

The paper presents two contributions in the context of the numerical simulation of magnetized fluid dynamics. First, we show how to extend the ideal magnetohydrodynamics (MHD) equations with an inbuilt magnetic field divergence cleaning mechanism in such a way that the resulting model is consistent with the second law of thermodynamics. As a byproduct of these derivations, we show that not all of the commonly used divergence cleaning extensions of the ideal MHD equations are thermodynamically consistent. Secondly, we present a numerical scheme obtained by constructing a specific finite volume discretization that is consistent with the discrete thermodynamic entropy. It includes a mechanism to control the discrete divergence error of the magnetic field by construction and is Galilean invariant. We implement the new high-order MHD solver in the adaptive mesh refinement code FLASH where we compare the divergence cleaning efficiency to the constrained transport solver available in FLASH (unsplit staggered mesh scheme).

Teachers' Ethnotheories of the "Ideal Student" in Five Western Cultures

ERIC Educational Resources Information Center

Harkness, Sara; Blom, Marjolijn; Oliva, Alfredo; Moscardino, Ughetta; Zylicz, Piotr Olaf; Bermudez, Moises Rios; Feng, Xin; Carrasco-Zylicz, Agnieszka; Axia, Giovanna; Super, Charles M.

2007-01-01

This paper explores teachers' ethnotheories of the "ideal student" in five western societies: Italy, The Netherlands, Poland, Spain, and the US. Quantitative and qualitative methods are used to derive culture-specific profiles of the "ideal student" as described by kindergarten and primary school teachers in semi-structured…

Thermodynamics of an ideal generalized gas: I. Thermodynamic laws.

PubMed

Lavenda, B H

2005-11-01

The equations of state for an ideal relativistic, or generalized, gas, like an ideal quantum gas, are expressed in terms of power laws of the temperature. In contrast to an ideal classical gas, the internal energy is a function of volume at constant temperature, implying that the ideal generalized gas will show either attractive or repulsive interactions. This is a necessary condition in order that the third law be obeyed and for matter to have an electromagnetic origin. The transition from an ideal generalized to a classical gas occurs when the two independent solutions of the subsidiary equation to Lagrange's equation coalesce. The equation of state relating the pressure to the internal energy encompasses the full range of cosmological scenarios, from the radiation to the matter dominated universes and finally to the vacuum energy, enabling the coefficient of proportionality, analogous to the Grüeisen ratio, to be interpreted in terms of the degrees of freedom related to the temperature exponents of the internal energy and the absolute temperature expressed in terms of a power of the empirical temperature. The limit where these exponents merge is shown to be the ideal classical gas limit. A corollary to Carnot's theorem is proved, asserting that the ratio of the work done over a cycle to the heat absorbed to increase the temperature at constant volume is the same for all bodies at the same volume. As power means, the energy and entropy are incomparable, and a new adiabatic potential is introduced by showing that the volume raised to a characteristic exponent is also the integrating factor for the quantity of heat so that the second law can be based on the property that power means are monotonically increasing functions of their order. The vanishing of the chemical potential in extensive systems implies that energy cannot be transported without matter and is equivalent to the condition that Clapeyron's equation be satisfied.

Pulsed photoacoustic flow imaging with a handheld system

NASA Astrophysics Data System (ADS)

van den Berg, Pim J.; Daoudi, Khalid; Steenbergen, Wiendelt

2016-02-01

Flow imaging is an important technique in a range of disease areas, but estimating low flow speeds, especially near the walls of blood vessels, remains challenging. Pulsed photoacoustic flow imaging can be an alternative since there is little signal contamination from background tissue with photoacoustic imaging. We propose flow imaging using a clinical photoacoustic system that is both handheld and portable. The system integrates a linear array with 7.5 MHz central frequency in combination with a high-repetition-rate diode laser to allow high-speed photoacoustic imaging-ideal for this application. This work shows the flow imaging performance of the system in vitro using microparticles. Both two-dimensional (2-D) flow images and quantitative flow velocities from 12 to 75 mm/s were obtained. In a transparent bulk medium, flow estimation showed standard errors of ˜7% the estimated speed; in the presence of tissue-realistic optical scattering, the error increased to 40% due to limited signal-to-noise ratio. In the future, photoacoustic flow imaging can potentially be performed in vivo using fluorophore-filled vesicles or with an improved setup on whole blood.

Quantification of non-ideal explosion violence with a shock tube

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackson, Scott I; Hill, Larry G

There is significant interest in quantifying the blast violence associated with various nonideal explosions. Such data is essential to evaluate the damage potential of both explosive cookoff and terrorist explosive scenarios. We present a technique designed to measure the source energy associated with a non-ideal, asymmetrical, and three-dimensional explosion. A tube is used to confine and focus energy from a blast event into a one-dimensional, quasi-planar shock front. During propagation along the length of the tube, the wave is allowed to shocksteepen into a more ideal form. Pressure transducers then measure the shock overpressure as a function of the distancemore » from the source. One-dimensional blast scaling theory allows calculation of the source energy from this data. This small-scale test method addresses cost and noise concerns as well as boosting and symmetry issues associated with large-scale, three-dimensional, blast arena tests. Results from both ideal explosives and non-ideal explosives are discussed.« less

Developmental Idealism and Cultural Models of the Family in Malawi

PubMed Central

Pierotti, Rachael S.; Young-DeMarco, Linda; Watkins, Susan

2014-01-01

This paper examines the extent to which developmental idealism has been disseminated in Malawi. Developmental idealism is a set of beliefs and values about development and the relationships between development and family structures and behavior. Developmental idealism states that attributes of societies and families defined as modern are better than attributes defined as traditional, that modern societies help produce modern families, that modern families facilitate the achievement of modern societies, and that the future will bring family change in the direction of modernity. Previous research has demonstrated that knowledge of developmental idealism is widespread in many places around the world, but provides little systematic data about it in sub-Saharan Africa or how knowledge of it is associated with certain demographic characteristics in that region. In this paper, we address this issue by examining whether ordinary people in two settings in Malawi, a sub-Saharan African country, have received and understood messages that are intended to associate development with certain types of family forms and family behaviors. We then examine associations between demographic characteristics and developmental idealism to investigate possible mechanisms linking global discourse about development to the grassroots. We analyze data collected in face-to-face surveys from two samples of Malawian men in 2009 and 2010, one rural, the other in a low-to-medium income neighborhood of a city. Our analysis of these survey data shows considerable evidence that many developmental idealism beliefs have been spread in that country and that education has positive effects on beliefs in the association between development and family attributes. We also find higher levels of developmental idealism awareness in the urban sample than we do in the rural sample, but once dissimilarities in education and wealth between the two samples are controlled, awareness levels no longer differed between

Ideal Internal Carotid Artery Trapping Technique without Bypass in a Patient with Insufficient Collateral Flow.

PubMed

Chung, Joon Ho; Shin, Yong Sam; Lim, Yong Cheol; Park, Minjung

2009-04-01

Internal carotid artery (ICA) trapping can be used for treating intracranial giant aneurysm, blood blister-like aneurysms and ICA rupture during the surgery. We present a novel ICA trapping technique which can be used with insufficient collaterals flow via anterior communicating artery (AcoA) and posterior communicating artery (PcoA). A patient was admitted with severe headache and the cerebral angiography demonstrated a typical blood blister-like aneurysm at the contralateral side of PcoA. For trapping the aneurysm, the first clip was placed at the ICA just proximal to the aneurysm whereas the distal clip was placed obliquely proximal to the origin of the PcoA to preserve blood flow from the PcoA to the distal ICA. The patient was completely recovered with good collaterals filling to the right ICA territories via AcoA and PcoA. This technique may be an effective treatment option for trapping the aneurysm, especially when the PcoA preservation is mandatory.

Health Care Market Deviations from the Ideal Market

PubMed Central

Mwachofi, Ari; Al-Assaf, Assaf F.

2011-01-01

A common argument in the health policy debate is that market forces allocate resources efficiently in health care, and that government intervention distorts such allocation. Rarely do those making such claims state explicitly that the market they refer to is an ideal in economic theory which can only exist under very strict conditions. This paper explores the strict conditions necessary for that ideal market in the context of health care as a means of examining the claim that market forces do allocate resources efficiently in health care. PMID:22087373

Highlights of 1978 activities

NASA Technical Reports Server (NTRS)

1978-01-01

General highlights of NASA's activities for 1978 are presented. The highlights are categorized into topics such as space science, space transportation systems, space and terrestrial applications, environment, technology utilization, aeronautics, space research and technology, energy programs, and international. A list of the 1978 launches including: (1) launch date; (2) payload designation; (3) launch vehicle; (4) launch site and (5) mission remarks is also presented.

ADER discontinuous Galerkin schemes for general-relativistic ideal magnetohydrodynamics

NASA Astrophysics Data System (ADS)

Fambri, F.; Dumbser, M.; Köppel, S.; Rezzolla, L.; Zanotti, O.

2018-07-01

We present a new class of high-order accurate numerical algorithms for solving the equations of general-relativistic ideal magnetohydrodynamics in curved space-times. In this paper, we assume the background space-time to be given and static, i.e. we make use of the Cowling approximation. The governing partial differential equations are solved via a new family of fully discrete and arbitrary high-order accurate path-conservative discontinuous Galerkin (DG) finite-element methods combined with adaptive mesh refinement and time accurate local time-stepping. In order to deal with shock waves and other discontinuities, the high-order DG schemes are supplemented with a novel a posteriori subcell finite-volume limiter, which makes the new algorithms as robust as classical second-order total-variation diminishing finite-volume methods at shocks and discontinuities, but also as accurate as unlimited high-order DG schemes in smooth regions of the flow. We show the advantages of this new approach by means of various classical two- and three-dimensional benchmark problems on fixed space-times. Finally, we present a performance and accuracy comparisons between Runge-Kutta DG schemes and ADER high-order finite-volume schemes, showing the higher efficiency of DG schemes.

ADER discontinuous Galerkin schemes for general-relativistic ideal magnetohydrodynamics

NASA Astrophysics Data System (ADS)

Fambri, F.; Dumbser, M.; Köppel, S.; Rezzolla, L.; Zanotti, O.

2018-03-01

We present a new class of high-order accurate numerical algorithms for solving the equations of general-relativistic ideal magnetohydrodynamics in curved spacetimes. In this paper we assume the background spacetime to be given and static, i.e. we make use of the Cowling approximation. The governing partial differential equations are solved via a new family of fully-discrete and arbitrary high-order accurate path-conservative discontinuous Galerkin (DG) finite-element methods combined with adaptive mesh refinement and time accurate local timestepping. In order to deal with shock waves and other discontinuities, the high-order DG schemes are supplemented with a novel a-posteriori subcell finite-volume limiter, which makes the new algorithms as robust as classical second-order total-variation diminishing finite-volume methods at shocks and discontinuities, but also as accurate as unlimited high-order DG schemes in smooth regions of the flow. We show the advantages of this new approach by means of various classical two- and three-dimensional benchmark problems on fixed spacetimes. Finally, we present a performance and accuracy comparisons between Runge-Kutta DG schemes and ADER high-order finite-volume schemes, showing the higher efficiency of DG schemes.

Thin-ideal internalization: How much is too much?

PubMed

Schaefer, Lauren M; Burke, Natasha L; Thompson, J Kevin

2018-03-16

Internalization of the thin-ideal is a risk factor for eating disorders that frequently persists into recovery and increases patient risk for relapse. Addressing thin-ideal internalization as a core element of eating disorder prevention and treatment produces significant reductions in eating pathology. However, research has not yet quantified levels of thin-ideal internalization that may signal increased versus decreased risk for disordered eating. To address this gap in the literature, receiver operating characteristic (ROC) curve analysis was used to identify a thin-ideal internalization cutoff score that signified clinically-meaningful eating disorder pathology. 787 college women (age M = 20.17, SD = 2.41; BMI M = 23.58, SD = 5.29) were classified as "healthy" (N = 717) or those with significant disordered eating (N = 70) using established clinical cutoffs for the Eating Disorder Examination-Questionnaire. ROC curve analysis was used to test the performance of the Sociocultural Attitudes Towards Appearance Questionnaire-4 (SATAQ-4) Internalization: Thin/Low Body Fat subscale in predicting disordered eating status, and to identify a cutoff score that maximized sensitivity and specificity to discriminate between healthy and disordered eating samples. Mean SATAQ-4 internalization scores were 3.29 (SD = 0.92) and 4.27 (SD = 0.62) for healthy and disordered eating participants, respectively. The SATAQ-4 internalization scores were good predictors of disordered eating status (area under the curve = 0.81, 95% CI: 0.76-0.86). The optimal cutoff of 3.78 (measured on a 1-5 Likert scale) yielded a sensitivity of 0.81 and specificity of 0.64. Overall, results provide preliminary support for the discriminant validity of SATAQ-4 thin internalization scores and suggest that even moderate levels of thin-ideal internalization may be predictive of clinically-significant eating pathology. It may be important for prevention and intervention work to actively seek to reduce

Internalization of the ultra-thin ideal: positive implicit associations with underweight fashion models are associated with drive for thinness in young women.

PubMed

Ahern, Amy L; Bennett, Kate M; Hetherington, Marion M

2008-01-01

This study examined whether young women who make implicit associations between underweight models and positive attributes report elevated eating disorder symptoms. Ninety nine female undergraduates completed a weight based implicit association test (IAT) and self report measures of body dissatisfaction, thin-ideal internalization and eating disorder symptoms. IAT scores were associated with drive for thinness (r = -0.26, p < 0.05). This relationship was moderated by attitude importance. The relationship between drive for thinness and IAT scores was stronger (r = 0.34; p < 0.02) in participants who report that the media is an important source of information about fashion and being attractive. The IAT used in the current study is sensitive enough to discriminate between participants on drive for thinness. Women who have developed cognitive schemas that associate being underweight with positive attributes report higher eating disorder symptoms. Attitude importance is highlighted as a key construct in thin ideal internalization.

Ideal Teaching: Exploring the Attributes of an "Ideal Teacher" in the Church Educational System for the Church of Jesus Christ of Latter-Day Saints

ERIC Educational Resources Information Center

Strader, Matthew W.

2009-01-01

The purpose of this study was to identify the profile of an ideal teacher for the Church Educational System (CES) for the Church of Jesus Christ of Latter-day Saints. This study surveyed 159 students, teachers, and administrators in order to find the characteristics perceived to be ideal in a CES teacher. The survey included 16 characteristics of…

Validity of Highlighting on Text Comprehension

NASA Astrophysics Data System (ADS)

So, Joey C. Y.; Chan, Alan H. S.

2009-10-01

In this study, 38 university students were tested with a Chinese reading task on an LED display under different task conditions for determining the effects of the highlighting and its validity on comprehension performance on light-emitting diodes (LED) display for Chinese reading. Four levels of validity (0%, 33%, 67% and 100%) and a control condition with no highlighting were tested. Each subject was required to perform the five experimental conditions in which different passages were read and comprehended. The results showed that the condition with 100% validity of highlighting was found to have better comprehension performance than other validity levels and conditions with no highlighting. The comprehension score of the condition without highlighting effect was comparatively lower than those highlighting conditions with distracters, though not significant.

Three-dimensional inspiratory flow in a double bifurcation airway model

NASA Astrophysics Data System (ADS)

Jalal, Sahar; Nemes, Andras; Van de Moortele, Tristan; Schmitter, Sebastian; Coletti, Filippo

2016-09-01

The flow in an idealized airway model is investigated for the steady inhalation case. The geometry consists of a symmetric planar double bifurcation that reflects the anatomical proportions of the human bronchial tree, and a wide range of physiologically relevant Reynolds numbers ( Re = 100-5000) is considered. Using magnetic resonance velocimetry, we analyze the three-dimensional fields of velocity and vorticity, along with flow descriptors that characterize the longitudinal and lateral dispersion. In agreement with previous studies, the symmetry of the flow partitioning is broken even at the lower Reynolds numbers, and at the second bifurcation, the fluid favors the medial branches over the lateral ones. This trend reaches a plateau around Re = 2000, above which the turbulent inflow results in smoothed mean velocity gradients. This also reduces the streamwise momentum flux, which is a measure of the longitudinal dispersion by the mean flow. The classic Dean-type counter-rotating vortices are observed in the first-generation daughter branches as a result of the local curvature. In the granddaughter branches, however, the secondary flows are determined by the local curvature only for the lower flow regimes ( Re ≤ 250), in which case the classic Dean mechanism prevails. At higher flow regimes, the field is instead dominated by streamwise vortices extending from the daughter into the medial granddaughter branches, where they rotate in the opposite direction with respect to Dean vortices. Circulation and secondary flow intensity show a similar trend as the momentum flux, increasing with Reynolds number up to Re = 2000 and then dropping due to turbulent dissipation of vorticity. The streamwise vortices interact both with each other and with the airway walls, and for Re > 500 they can become stronger in the medial granddaughter than in the upstream daughter branches. With respect to realistic airway models, the idealized geometry produces weaker secondary flows

Computations of non-reacting and reacting viscous blunt body flows, volume 2

NASA Technical Reports Server (NTRS)

Li, C. P.

1973-01-01

Computer programs for calculating the flow distribution in the nose region of a blunt body at arbitrary speed and altitude are discussed. The programs differ from each other in their ability to consider either thin shock or thick shock conditions and in the use of either ideal, equilibrium air, or nonequilibrium air chemistry. The application of the programs to analyzing the flow distribution around the nose of the shuttle orbiter during reentry is reported.

Stability of magnetohydrodynamic Dean Flow as applied to centrifugally confined plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hassam, A.B.

1999-10-01

Dean Flow is the azimuthal flow of fluid between static concentric cylinders. In a magnetized plasma, there may also be radial stratification of the pressure. The ideal magnetohydrodynamic stability of such a flow in the presence of a strong axial magnetic field and an added radial gravitational force is examined. It is shown that both the Kelvin{endash}Helmholtz instability and pressure-gradient-driven interchanges can be stabilized if the flow is driven by a unidirectional external force and if the plasma annulus is sufficiently thin (large aspect ratio). These results find application in schemes using centrifugal confinement of plasma for fusion. {copyright} {italmore » 1999 American Institute of Physics.}« less

Your Ideal Silhouette. Courseware Evaluation for Vocational and Technical Education.

ERIC Educational Resources Information Center

Tierney, Margaret S.; And Others

This courseware evaluation rates the "Your Ideal Silhouette" program developed by Your Image, Inc. This program (not contained in this document) uses the computer to identify figure faults and illustrate personalized corrective style lines to achieve the ideal silhouette. Part A describes the program in terms of subject area (textiles…

The "Ideal Professor" and Gender Effects in Christian Higher Education

ERIC Educational Resources Information Center

Woods, Robert H., Jr.; Badzinski, Diane M.; Fritz, Janie M. Harden; Yeates, Sarah E.

2012-01-01

A survey was administered to 451 undergraduate students at a private liberal arts Christian university to identify students' perceptions of the ideal professor. The survey revealed that the ideal professor places great emphasis on the integration of faith and learning, is flexible (and even easy), maintains high academic standards, encourages…

Why the Kantian ideal survives medical learning curves, and why it matters.

PubMed

Brecher, B

2006-09-01

The "Kantian ideal" is often misunderstood as invoking individual autonomy rather than rational self legislation. Le Morvan and Stock's otherwise insightful discussion of "Medical learning curves and the Kantian ideal"--for example--draws the mistaken inference that that ideal is inconsistent with the realities of medical practice. But it is not. Rationally to be a patient entails accepting its necessary conditions.

Preliminary characterization of an expanding flow of siloxane vapor MDM

NASA Astrophysics Data System (ADS)

Spinelli, A.; Cozzi, F.; Cammi, G.; Zocca, M.; Gaetani, P.; Dossena, V.; Guardone, A.

2017-03-01

The early experimental results on the characterization of expanding flows of siloxane vapor MDM (C8H24O2Si3, octamethyltrisiloxane) are presented. The measurements were performed on the Test Rig for Organic VApors (TROVA) at the CREA Laboratory of Politecnico di Milano. The TROVA test-rig was built in order to investigate the non-ideal compressible-fluid behavior of typical expanding flows occurring within organic Rankine cycles (ORC) turbine passages. The test rig implements a batch Rankine cycle where a planar converging-diverging nozzle replaces the turbine and represents a test section. Investigations related to both fields of non-ideal compressible-fluid dynamics fundamentals and turbomachinery are allowed. The nozzle can be operated with different working fluids and operating conditions aiming at measuring independently the pressure, the temperature and the velocity field and thus providing data to verify the thermo-fluid dynamic models adopted to predict the behavior of these flows. The limiting values of pressure and temperature are 50 bar and 400 °C respectively. The early measurements are performed along the nozzle axis, where an isentropic process is expected to occur. In particular, the results reported here refer to the nozzle operated in adapted conditions using the siloxane vapor MDM as working fluid in thermodynamic regions where mild to medium non-ideal compressible-fluid effects are present. Both total temperature and total pressure of the nozzle are measured upstream of the test section, while static pressure are measured along the nozzle axis. Schlieren visualizations are also carried out in order to complement the pressure measurement with information about the 2D density gradient field. The Laser Doppler Velocimetry technique is planned to be used in the future for velocity measurements. The measured flow field has also been interpreted by resorting to the quasi-one-dimensional theory and two dimensional CFD viscous calculation. In both cases

Developmental Idealism: The Cultural Foundations of World Development Programs

PubMed Central

Thornton, Arland; Dorius, Shawn F.; Swindle, Jeffrey

2015-01-01

This paper extends theory and research concerning cultural models of development beyond family and demographic matters to a broad range of additional factors, including government, education, human rights, daily social conventions, and religion. Developmental idealism is a cultural model—a set of beliefs and values—that identifies the appropriate goals of development and the ends for achieving these goals. It includes beliefs about positive cause and effect relationships among such factors as economic growth, educational achievement, health, and political governance, as well as strong values regarding many attributes, including economic growth, education, small families, gender equality, and democratic governance. This cultural model has spread from its origins among the elites of northwest Europe to elites and ordinary people throughout the world. Developmental idealism has become so entrenched in local, national, and global social institutions that it has now achieved a taken-for-granted status among many national elites, academics, development practitioners, and ordinary people around the world. We argue that developmental idealism culture has been a fundamental force behind many cultural clashes within and between societies, and continues to be an important cause of much global social change. We suggest that developmental idealism should be included as a causal factor in theories of human behavior and social change. PMID:26457325

Neurocultural evidence that ideal affect match promotes giving.

PubMed

Park, BoKyung; Blevins, Elizabeth; Knutson, Brian; Tsai, Jeanne L

2017-07-01

Why do people give to strangers? We propose that people trust and give more to those whose emotional expressions match how they ideally want to feel ("ideal affect match"). European Americans and Koreans played multiple trials of the Dictator Game with recipients who varied in emotional expression (excited, calm), race (White, Asian) and sex (male, female). Consistent with their culture's valued affect, European Americans trusted and gave more to excited than calm recipients, whereas Koreans trusted and gave more to calm than excited recipients. These findings held regardless of recipient race and sex. We then used fMRI to probe potential affective and mentalizing mechanisms. Increased activity in the nucleus accumbens (associated with reward anticipation) predicted giving, as did decreased activity in the right temporo-parietal junction (rTPJ; associated with reduced belief prediction error). Ideal affect match decreased rTPJ activity, suggesting that people may trust and give more to strangers whom they perceive to share their affective values. © The Author (2017). Published by Oxford University Press.

Perceptual thresholds for non-ideal diffuse field reverberation.

PubMed

Romblom, David; Guastavino, Catherine; Depalle, Philippe

2016-11-01

The objective of this study is to understand listeners' sensitivity to directional variations in non-ideal diffuse field reverberation. An ABX discrimination test was conducted using a semi-spherical 28-loudspeaker array; perceptual thresholds were estimated by systematically varying the level of a segment of loudspeakers for lateral, height, and frontal conditions. The overall energy was held constant using a gain compensation scheme. When compared to an ideal diffuse field, the perceptual threshold for detection is -2.5 dB for the lateral condition, -6.8 dB for the height condition, and -3.2 dB for the frontal condition. Measurements of the experimental stimuli were analyzed using a Head and Torso Simulator as well as with opposing cardioid microphones aligned on the three Cartesian axes. Additionally, opposing cardioid measurements made in an acoustic space demonstrate that level differences corresponding to the perceptual thresholds can be found in practice. These results suggest that non-ideal diffuse field reverberation may be a previously unrecognized component of spatial impression.

Vectorization of a particle simulation method for hypersonic rarefied flow

NASA Technical Reports Server (NTRS)

Mcdonald, Jeffrey D.; Baganoff, Donald

1988-01-01

An efficient particle simulation technique for hypersonic rarefied flows is presented at an algorithmic and implementation level. The implementation is for a vector computer architecture, specifically the Cray-2. The method models an ideal diatomic Maxwell molecule with three translational and two rotational degrees of freedom. Algorithms are designed specifically for compatibility with fine grain parallelism by reducing the number of data dependencies in the computation. By insisting on this compatibility, the method is capable of performing simulation on a much larger scale than previously possible. A two-dimensional simulation of supersonic flow over a wedge is carried out for the near-continuum limit where the gas is in equilibrium and the ideal solution can be used as a check on the accuracy of the gas model employed in the method. Also, a three-dimensional, Mach 8, rarefied flow about a finite-span flat plate at a 45 degree angle of attack was simulated. It utilized over 10 to the 7th particles carried through 400 discrete time steps in less than one hour of Cray-2 CPU time. This problem was chosen to exhibit the capability of the method in handling a large number of particles and a true three-dimensional geometry.

Community governance in primary health care: towards an international Ideal Type.

PubMed

Meads, Geoffrey; Russell, Grant; Lees, Amanda

2017-10-01

Against a global background of increased resource management responsibilities for primary health care agencies, general medical practices, in particular, are increasingly being required to demonstrate the legitimacy of their decision making in market oriented environments. In this context a scoping review explores the potential utility for health managers in primary health care of community governance as a policy concept. The review of recent research suggests that applied learning from international health systems with enhanced approaches to public and patient involvement may contribute to meeting this requirement. Such approaches often characterise local health systems in Latin America and North West Europe where innovative models are beginning to respond effectively to the growing demands on general practice. The study design draws on documentary and secondary data analyses to identify common components of community governance from the countries in these regions, supplemented by other relevant international studies and sources where appropriate. Within a comprehensive framework of collaborative governance the components are aggregated in an Ideal Type format to provide a point of reference for possible adaptation and transferable learning across market oriented health systems. Each component is illustrated with international exemplars from recent organisational practices in primary health care. The application of community governance is considered for the particular contexts of GP led Clinical Commissioning Groups in England and Primary Health Networks in Australia. Some components of the Ideal Type possess potentially powerful negative as well as positive motivational effects, with PPI at practice levels sometimes hindering the development of effective local governance. This highlights the importance of careful and competent management of the growing resources attributed to primary health care agencies, which possess an increasingly diverse range of non

Measuring explosive non-ideality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Souers, P C

1999-02-17

The sonic reaction zone length may be measured by four methods: (1) size effect, (2) detonation front curvature, (3) crystal interface velocity and (4) in-situ gauges. The amount of data decreases exponentially from (1) to (4) with there being almost no gauge data for prompt detonation at steady state. The ease and clarity of obtaining the reaction zone length increases from (1) to (4). The method of getting the reaction zone length, , is described for the four methods. A measure of non-ideality is proposed: the reaction zone length divided by the cylinder radius. N = /R{sub o}.more » N = 0 for true ideality. It also decreases with increasing radius as it should. For N < 0.10, an equilibrium EOS like the JWL may be used. For N > 0.10, a time-dependent description is essential. The crystal experiment, which measures the particle velocity of an explosive-transparent material interface, is presently rising in importance. We examine the data from three experiments and apply: (1) an impedance correction that transfers the explosive C-J particle velocity to the corresponding value for the interface, and (2) multiplies the interface time by 3/4 to simulate the explosive speed of sound. The result is a reaction zone length comparable to those obtained by other means. A few explosives have reaction zones so small that the change of slope in the particle velocity is easily seen.« less

The effect of priming materialism on women's responses to thin-ideal media.

PubMed

Ashikali, Eleni-Marina; Dittmar, Helga

2012-12-01

Consumer culture is characterized by two prominent ideals: the 'body perfect' and the material 'good life'. Although the impact of these ideals has been investigated in separate research literatures, no previous research has examined whether materialism is linked to women's responses to thin-ideal media. Data from several studies confirm that the internalization of materialistic and body-ideal values is positively linked in women. After developing a prime for materialism (N = 50), we present an experimental examination (N = 155) of the effects of priming materialism on women's responses to thin-ideal media, using multiple outcome measures of state body dissatisfaction. Priming materialism affects women's body dissatisfaction after exposure to thin media models, but differently depending on the dimension of body image measured. The two main novel findings are that (1) priming materialism heightens the centrality of appearance to women's self-concept and (2) priming materialism influences the activation of body-related self-discrepancies (BRSDs), particularly for highly materialistic women. Exposure to materialistic media has a clear influence on women's body image, with trait materialism a further vulnerability factor for negative exposure effects in response to idealized, thin media models. ©2011 The British Psychological Society.

Quantum cryptography with an ideal local relay

NASA Astrophysics Data System (ADS)

Spedalieri, Gaetana; Ottaviani, Carlo; Braunstein, Samuel L.; Gehring, Tobias; Jacobsen, Christian S.; Andersen, Ulrik L.; Pirandola, Stefano

2015-10-01

We consider two remote parties connected to a relay by two quantum channels. To generate a secret key, they transmit coherent states to the relay, where the states are subject to a continuous-variable (CV) Bell detection. We study the ideal case where Alice's channel is lossless, i.e., the relay is locally in her lab and the Bell detection is perfomed with unit efficiency. This configuration allows us to explore the optimal performances achievable by CV measurement-device-independent quantum key distribution. This corresponds to the limit of a trusted local relay, where the detection loss can be re-scaled. Our theoretical analysis is confirmed by an experimental simulation where 10-4 secret bits per use can potentially be distributed at 170km assuming ideal reconciliation.

Self-guide framing and persuasion: responsibly increasing message processing to ideal levels.

PubMed

Evans, Lisa M; Petty, Richard E

2003-03-01

The current research examines the effect that framing persuasive messages in terms of self-guides (ideal vs. ought) has on the attitudes and cognitive responses of individuals with chronic ideal versus ought self-guides. The strength of participants' ideal and ought self-guides and the magnitude of participants' ideal and ought self-discrepancies were measured using a computerized reaction time program. One week later, participants read a persuasive message about a fictional breakfast product, framed in terms of either ideals or oughts. Matching framing to stronger self-guide led to enhanced message processing activity, especially among individuals who were low in need for cognition. Individuals who read messages framed to match their stronger self-guides paid more attention to argument quality, as reflected in their attitudes and cognitive responses. Messages with self-guide framing that matched individuals' stronger self-discrepancies did not have this effect on processing.

A Darker Shade of Love: Machiavellianism and Positive Assortative Mating Based on Romantic Ideals

PubMed Central

Ináncsi, Tamás; Láng, András; Bereczkei, Tamás

2016-01-01

Machiavellianism is a personality trait that is characterized by manipulative and exploitative attitude toward others, lack of empathy, and a cynical view of human nature. In itself or as part of the Dark Triad it has been the target of several studies investigating romantic relations. Nevertheless, the relationship between Machiavellianism and romantic ideals has not been revealed yet. An undergraduate sample of 143 (92 females) with an average age of 19.83 years (SD = 1.51 years) filled out self-report measures of Machiavellianism (Mach-IV Scale) and romantic ideals (Ideal Standards Scale and NEO-FFI-IDEAL). According to our results, Machiavellianism correlated negatively with the importance of partner’s warmth-trustworthiness, extraversion, openness, agreeableness, and with the importance of intimacy and loyalty in their ideal relationships. Machiavellianism correlated positively with the ideal partner’s possession over status and resources. Explorative factor analysis revealed three components of ideal partner’s characteristics. Machiavellianism loaded significantly on two out of three components. Results are discussed with regard to Ideal Standards Model and the Big Five model of personality. PMID:27247697

Ambivalent Sexism in Close Relationships: (Hostile) Power and (Benevolent) Romance Shape Relationship Ideals

PubMed Central

Lee, Tiane L.; Fiske, Susan T.; Glick, Peter; Chen, Zhixia

2013-01-01

Gender-based structural power and heterosexual dependency produce ambivalent gender ideologies, with hostility and benevolence separately shaping close-relationship ideals. The relative importance of romanticized benevolent versus more overtly power-based hostile sexism, however, may be culturally dependent. Testing this, northeast US (N=311) and central Chinese (N=290) undergraduates rated prescriptions and proscriptions (ideals) for partners and completed Ambivalent Sexism and Ambivalence toward Men Inventories (ideologies). Multiple regressions analyses conducted on group-specific relationship ideals revealed that benevolent ideologies predicted partner ideals, in both countries, especially for US culture’s romance-oriented relationships. Hostile attitudes predicted men’s ideals, both American and Chinese, suggesting both societies’ dominant-partner advantage. PMID:23914004

Shock wave interactions in hypervelocity flow

NASA Astrophysics Data System (ADS)

Sanderson, S. R.; Sturtevant, B.

1994-08-01

The impingement of shock waves on blunt bodies in steady supersonic flow is known to cause extremely high local heat transfer rates and surface pressures. Although these problems have been studied in cold hypersonic flow, the effects of dissociative relaxation processes are unknown. In this paper we report a model aimed at determining the boundaries of the possible interaction regimes for an ideal dissociating gas. Local analysis about shock wave intersection points in the pressure-flow deflection angle plane with continuation of singular solutions is the fundamental tool employed. Further, we discuss an experimental investigation of the nominally two-dimensional mean flow that results from the impingement of an oblique shock wave on the leading edge of a cylinder. The effects of variations in shock impingement geometry were visualized using differential interferometry. Generally, real gas effects are seen to increase the range of shock impingement points for which enhanced heating occurs. They also reduce the type 4 interaction supersonic jet width and influence the type 2-3 transition process.

Research and Development Highlights 1997

DOT National Transportation Integrated Search

1997-01-01

This report contains highlights of the major accomplishments and applications that have been made by Airport and Aircraft Safety researchers and by our university, industry, and government colleagues during the past year. The highlights illustrate bo...

Kinetic modeling of non-ideal explosives with CHEETAH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fried, L E; Howard, W M; Souers, P C

1998-08-06

We report an implementation of the Wood-Kirkwood kinetic detonation model based on multi-species equations of state and multiple reaction rate laws. Finite rate laws are used for the slowest chemical reactions. Other reactions are given infinite rates and are kept in constant thermodynamic equilibrium. We model a wide range of ideal and non-ideal composite energetic materials. We find that we can replicate experimental detonation velocities to within a few per cent, while obtaining good agreement with estimated reaction zone lengths. The detonation velocity as a function of charge radius is also correctly reproduced.

Complexity of culture: the role of identity and context in bicultural individuals' body ideals.

PubMed

Guan, Mei; Lee, Fiona; Cole, Elizabeth R

2012-07-01

Culture plays an important role in shaping body image, and people from different cultures have different beliefs about what constitutes the "ideal" body type. This study examines the relationship between culture and body ideals in Asian-American and Black-American women. Results from two studies show that subjective cultural identity and situational cultural cues had different relationships with body ideals. Among Asian-American women, identification with Asian culture was related to a thinner body ideal, but exposure to Asian cultural cues (relative to American cultural cues) was related to a thicker body ideal. Among Black-American women, identification with Black culture was related to a thicker body ideal, but exposure to Black cultural cues (relative to American cultural cues) was related to a thinner body ideal. These results have theoretical and practical implications for understanding how internal and external manifestations of culture can differentially influence body image.

Idealized numerical studies of gravity wave alteration in the tropopause region

NASA Astrophysics Data System (ADS)

Bense, Vera; Spichtinger, Peter

2017-04-01

When travelling through the tropopause region, characterised by strong gradients in static stability, wind shear and trace gases, the properties of gravity waves often change drastically. Within this work, the EULAG model (Prusa et al., 2008) is used to provide an idealized setup for sensitivity studies on these modifications. The characteristics of the tropopause are introduced by specifiying environmental profiles for Brunt-Väisälä frequency and horizontal wind speed, partly extracted from measurement and reanalysis data. Tropospheric and stratospheric wave spectra extracted for flows under varying tropopause sharpness are analysed, respectively. In particular, different regimes for transmission behaviour are classified for a series of Brunt-Väisälä frequency profiles showing a tropopause inversion layer (TIL, see e.g. Birner et al., 2002). Furthermore, this study focusses on the comparison of transmission coefficients deduced from numerical simulations with values derived from asymptotical analysis of the governing equations and investigates where the threshold of linear behaviour are for the respective setups, The wave generation is implemented in the model both through topography at the lower model domain and through the prescription of wave packets at initialization of the simulations. References: Prusa, J. M., P. K. Smolarkiewicz, P. K. and A. A. Wyszogrodzki, 2008: EULAG, a computational model for multiscale flows, Computers & Fluids 37, 1193-1207 Birner, T., A. Doernbrack, and U. Schumann, 2002: How sharp is the tropopause at midlatitudes?, Geophys. Res. Lett., 29, 1700, doi:10.1029/2002GL015142.

Chemical reacting flows

NASA Technical Reports Server (NTRS)

Mularz, Edward J.; Sockol, Peter M.

1987-01-01

Future aerospace propulsion concepts involve the combination of liquid or gaseous fuels in a highly turbulent internal air stream. Accurate predictive computer codes which can simulate the fluid mechanics, chemistry, and turbulence combustion interaction of these chemical reacting flows will be a new tool that is needed in the design of these future propulsion concepts. Experimental and code development research is being performed at Lewis to better understand chemical reacting flows with the long term goal of establishing these reliable computer codes. The approach to understanding chemical reacting flows is to look at separate simple parts of this complex phenomena as well as to study the full turbulent reacting flow process. As a result research on the fluid mechanics associated with chemical reacting flows was initiated. The chemistry of fuel-air combustion is also being studied. Finally, the phenomena of turbulence-combustion interaction is being investigated. This presentation will highlight research, both experimental and analytical, in each of these three major areas.

Chemical reacting flows

NASA Technical Reports Server (NTRS)

Mularz, Edward J.; Sockol, Peter M.

1990-01-01

Future aerospace propulsion concepts involve the combustion of liquid or gaseous fuels in a highly turbulent internal airstream. Accurate predictive computer codes which can simulate the fluid mechanics, chemistry, and turbulence-combustion interaction of these chemical reacting flows will be a new tool that is needed in the design of these future propulsion concepts. Experimental and code development research is being performed at LeRC to better understand chemical reacting flows with the long-term goal of establishing these reliable computer codes. Our approach to understand chemical reacting flows is to look at separate, more simple parts of this complex phenomenon as well as to study the full turbulent reacting flow process. As a result, we are engaged in research on the fluid mechanics associated with chemical reacting flows. We are also studying the chemistry of fuel-air combustion. Finally, we are investigating the phenomenon of turbulence-combustion interaction. Research, both experimental and analytical, is highlighted in each of these three major areas.

Current and ideal skin tone: Associations with tanning behavior among sexual minority men.

PubMed

Klimek, Patrycja; Lamb, Kalina M; Nogg, Kelsey A; Rooney, Benjamin M; Blashill, Aaron J

2018-06-01

Sexual minority men have high rates of skin cancer, yet little is known about skin cancer risk behaviors in this population. It was hypothesized that current skin tone would moderate the association between darker ideals and tanning behaviors. Data were collected online from 231 sexual minority men in San Diego, United States of America, with a mean age of 24.66 (SD = 5.44). Ideal and current skin tone ratings and indoor and outdoor tanning behaviors were assessed. Darker ideals were significantly associated with increased indoor and outdoor tanning. The effect of darker ideals on tanning was strongest among individuals with lighter current skin tone, indicating a significant interaction. Sexual minority men whose perceived skin tone did not match their ideal were more likely to engage in skin cancer risk behaviors. Future skin cancer prevention programs aimed at sexual minority men may consider techniques that modify ideal skin tone internalization. Copyright © 2018 Elsevier Ltd. All rights reserved.

Investigating synoptic-scale monsoonal disturbances in an idealized moist model

NASA Astrophysics Data System (ADS)

Clark, S.; Ming, Y.

2017-12-01

Recent studies have highlighted the potential utility of a theory for a "moisture-dynamical" instability in explaining the time and spatial scales of intra-seasonal variability associated with the Indian summer monsoon. These studies suggest that a localized region in the subtropics with mean low-level westerly winds and mean temperature increasing poleward will allow the formation of westward propagating precipitation anomalies associated with moist Rossby-like waves. Here we test this theory in an idealized moist model with realistic radiative transfer by inducing a local poleward-increasing temperature gradient by placing a continent with simplified hydrology in the subtropics. We experiment with different treatments of land-surface hydrology, ranging from the extreme (treating land as having the same heat capacity as the slab ocean used in the model, and turning off evaporation completely over land) to the more realistic (bucket hydrology, with a decreased heat capacity over land), and different continental shapes, ranging from a zonally-symmetric continent, to Earth-like continental geometry. Precipitation rates produced by the simulations are analyzed using space-time spectral analysis, and connected to variability in the winds through regression analysis. The observed behavior is discussed with respect to predictions from the theory.

Water: The Ideal Early Learning Environment

ERIC Educational Resources Information Center

Grosse, Susan J.

2008-01-01

Bathtubs and swimming pools provide the ideal learning environment for people with special needs. For young preschool children, the activities that take place through water can help them develop physical fitness, facilitate motor development, reinforce perceptual-motor ability, encourage social development, and enhance self-esteem and confidence.…

The benchmark aeroelastic models program: Description and highlights of initial results

NASA Technical Reports Server (NTRS)

Bennett, Robert M.; Eckstrom, Clinton V.; Rivera, Jose A., Jr.; Dansberry, Bryan E.; Farmer, Moses G.; Durham, Michael H.

1991-01-01

An experimental effort was implemented in aeroelasticity called the Benchmark Models Program. The primary purpose of this program is to provide the necessary data to evaluate computational fluid dynamic codes for aeroelastic analysis. It also focuses on increasing the understanding of the physics of unsteady flows and providing data for empirical design. An overview is given of this program and some results obtained in the initial tests are highlighted. The tests that were completed include measurement of unsteady pressures during flutter of rigid wing with a NACA 0012 airfoil section and dynamic response measurements of a flexible rectangular wing with a thick circular arc airfoil undergoing shock boundary layer oscillations.

Highlights from Fermilab

NASA Astrophysics Data System (ADS)

Oddone, P. J.

2010-12-01

DISCUSSION by CHAIRMAN: P.J. ODDONE, Scientific Secretaries: W. Fisher, A. Holzner Note from Publisher: The Slides of the Lecture: "Highlights from Fermilab" can be found at http://www.ccsem.infn.it/issp2007/

"The part of me that you bring out": ideal similarity and the Michelangelo phenomenon.

PubMed

Rusbult, Caryl E; Kumashiro, Madoka; Kubacka, Kaska E; Finkel, Eli J

2009-01-01

This work examines the Michelangelo phenomenon, an interpersonal model of the means by which people move closer to (vs. further from) their ideal selves. The authors propose that partner similarity--similarity to the ideal self, in particular--plays an important role in this process. Across 4 studies employing diverse designs and measurement techniques, they observed consistent evidence that when partners possess key elements of one another's ideal selves, each person affirms the other by eliciting important aspects of the other's ideals, each person moves closer to his or her ideal self, and couple well-being is enhanced. Partner similarity to the actual self also accounts for unique variance in key elements of this model. The associations of ideal similarity and actual similarity with couple well-being are fully attributable to the Michelangelo process, to partner affirmation and target movement toward the ideal self. The authors also performed auxiliary analyses to rule out several alternative interpretations of these findings.

Stirling Engine With Radial Flow Heat Exchangers

NASA Technical Reports Server (NTRS)

Vitale, N.; Yarr, George

1993-01-01

Conflict between thermodynamical and structural requirements resolved. In Stirling engine of new cylindrical configuration, regenerator and acceptor and rejector heat exchangers channel flow of working gas in radial direction. Isotherms in regenerator ideally concentric cylinders, and gradient of temperature across regenerator radial rather than axial. Acceptor and rejector heat exchangers located radially inward and outward of regenerator, respectively. Enables substantial increase in power of engine without corresponding increase in diameter of pressure vessel.

Atmospheric Research 2011 Technical Highlights

NASA Technical Reports Server (NTRS)

2012-01-01

The 2011 Technical Highlights describes the efforts of all members of Atmospheric Research. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

Ideal light concentrators with reflector gaps

DOEpatents

Winston, Roland

1980-01-01

A cylindrical or trough-like radiant energy concentration and collection device is provided. The device includes an energy absorber, a glazing enveloping the absorber and a reflective wall. The ideal contour of the reflective wall is determined with reference to a virtual absorber and not the actual absorber cross section.

Ideal MHD Stability Prediction and Required Power for EAST Advanced Scenario

NASA Astrophysics Data System (ADS)

Chen, Junjie; Li, Guoqiang; Qian, Jinping; Liu, Zixi

2012-11-01

The Experimental Advanced Superconducting Tokamak (EAST) is the first fully superconducting tokamak with a D-shaped cross-sectional plasma presently in operation. The ideal magnetohydrodynamic (MHD) stability and required power for the EAST advanced tokamak (AT) scenario with negative central shear and double transport barrier (DTB) are investigated. With the equilibrium code TOQ and stability code GATO, the ideal MHD stability is analyzed. It is shown that a moderate ratio of edge transport barriers' (ETB) height to internal transport barriers' (ITBs) height is beneficial to ideal MHD stability. The normalized beta βN limit is about 2.20 (without wall) and 3.70 (with ideal wall). With the scaling law of energy confinement time, the required heating power for EAST AT scenario is calculated. The total heating power Pt increases as the toroidal magnetic field BT or the normalized beta βN is increased.

Good feelings in christianity and buddhism: religious differences in ideal affect.

PubMed

Tsai, Jeanne L; Miao, Felicity F; Seppala, Emma

2007-03-01

Affect valuation theory (AVT) predicts cultural variation in the affective states that people ideally want to feel (i.e., "ideal affect"). National and ethnic comparisons support this prediction: For instance, European Americans (EA) value high arousal positive (HAP) states (e.g., excitement) more and low arousal positive (LAP) states (e.g., calm) less than Hong Kong Chinese. In this article, the authors examine whether religions differ in the ideal affective states they endorse. The authors predicted that Christianity values HAP more and LAP less than Buddhism. In Study 1, they compared Christian and Buddhist practitioners' ideal affect. In Studies 2 and 3, they compared the endorsement of HAP and LAP in Christian and Buddhist classical texts (e.g., Gospels, Lotus Sutra) and contemporary self-help books (e.g., Your Best Life Now, Art of Happiness). Findings supported predictions, suggesting that AVT applies to religious and to national and ethnic cultures.

Flow cytometric characterization of cerebrospinal fluid cells.

PubMed

de Graaf, Marieke T; de Jongste, Arjen H C; Kraan, Jaco; Boonstra, Joke G; Sillevis Smitt, Peter A E; Gratama, Jan W

2011-09-01

Flow cytometry facilitates the detection of a large spectrum of cellular characteristics on a per cell basis, determination of absolute cell numbers and detection of rare events with high sensitivity and specificity. White blood cell (WBC) counts in cerebrospinal fluid (CSF) are important for the diagnosis of many neurological disorders. WBC counting and differential can be performed by microscopy, hematology analyzers, or flow cytometry. Flow cytometry of CSF is increasingly being considered as the method of choice in patients suspected of leptomeningeal localization of hematological malignancies. Additionally, in several neuroinflammatory diseases such as multiple sclerosis and paraneoplastic neurological syndromes, flow cytometry is commonly performed to obtain insight into the immunopathogenesis of these diseases. Technically, the low cellularity of CSF samples, combined with the rapidly declining WBC viability, makes CSF flow cytometry challenging. Comparison of flow cytometry with microscopic and molecular techniques shows that each technique has its own advantages and is ideally combined. We expect that increasing the number of flow cytometric parameters that can be simultaneously studied within one sample, will further refine the information on CSF cell subsets in low-cellular CSF samples and enable to define cell populations more accurately. Copyright © 2011 International Clinical Cytometry Society.

Ideal Gas Laws: Experiments for General Chemistry

ERIC Educational Resources Information Center

Deal, Walter J.

1975-01-01

Describes a series of experiments designed to verify the various relationships implicit in the ideal gas equation and shows that the success of the Graham's law effusion experiments can be explained by elementary hydrodynamics. (GS)

Complementary construction of ideal nonimaging concentrators and its applications.

PubMed

Gordon, J M

1996-10-01

A construction principle for ideal nonimaging concentrators based on the complementary edge rays outside the nominal field of view is presented, with illustrations for the trumpet, compound parabolic concentrator, and compound hyperbolic concentrator. A simple string construction for the trumpet concentrator is shown to follow from this observation-the trumpet having been the one ideal concentrator for which no string-construction method had previously been noted. An application of these observations for solar concentrator design when nonisothermal receivers are advantageous is also presented.

Highlighting non-uniform temperatures close to liquid/solid surfaces

NASA Astrophysics Data System (ADS)

Noirez, L.; Baroni, P.; Bardeau, J. F.

2017-05-01

The present experimental measurements reveal that similar to external fields such as electric, magnetic, or flow fields, the vicinity of a solid surface can preclude the liquid molecules from relaxing to equilibrium, generating located non-uniform temperatures. The non-uniform temperature zone extends up to several millimeters within the liquid with a lower temperature near the solid wall (reaching ΔT = -0.15 °C ± 0.02 °C in the case of liquid water) counterbalanced at larger distances by a temperature rise. These effects highlighted by two independent methods (thermistor measurement and infra-red emissivity) are particularly pronounced for highly wetting surfaces. The scale over which non-uniform temperatures are extended indicates that the effect is assisted by intermolecular interactions, in agreement with recent developments showing that liquids possess finite shear elasticity and theoretical approaches integrating long range correlations.

Sodium nitroprusside increases human skeletal muscle blood flow, but does not change flow distribution or glucose uptake.

PubMed

Pitkanen, O P; Laine, H; Kemppainen, J; Eronen, E; Alanen, A; Raitakari, M; Kirvela, O; Ruotsalainen, U; Knuuti, J; Koivisto, V A; Nuutila, P

1999-12-15

1. The role of blood flow as a determinant of skeletal muscle glucose uptake is at present controversial and results of previous studies are confounded by possible direct effects of vasoactive agents on glucose uptake. Since increase in muscle blood flow can be due to increased flow velocity or recruitment of new capillaries, or both, it would be ideal to determine whether the vasoactive agent affects flow distribution or only increases the mean flow. 2. In the present study blood flow, flow distribution and glucose uptake were measured simultaneously in both legs of 10 healthy men (aged 29 +/- 1 years, body mass index 24 +/- 1 kg m-2) using positron emission tomography (PET) combined with [15O]H2O and [18F]fluoro-2-deoxy-D-glucose (FDG). The role of blood flow in muscle glucose uptake was studied by increasing blood flow in one leg with sodium nitroprusside (SNP) and measuring glucose uptake simultaneously in both legs during euglycaemic hyperinsulinaemia (insulin infusion 6 pmol kg-1 min-1). 3. SNP infusion increased skeletal muscle blood flow by 86 % (P < 0.01), but skeletal muscle flow distribution and insulin-stimulated glucose uptake (61.4 +/- 7. 5 vs. 67.0 +/- 7.5 micromol kg-1 min-1, control vs. SNP infused leg, not significant), as well as flow distribution between different tissues of the femoral region, remained unchanged. The effect of SNP infusion on blood flow and distribution were unchanged during infusion of physiological levels of insulin (duration, 150 min). 4. Despite a significant increase in mean blood flow induced by an intra-arterial infusion of SNP, glucose uptake and flow distribution remained unchanged in resting muscles of healthy subjects. These findings suggest that SNP, an endothelium-independent vasodilator, increases non-nutritive, but not nutritive flow or capillary recruitment.

Critical Reflection as a Rationalistic Ideal

ERIC Educational Resources Information Center

van Woerkom, Marianne

2010-01-01

There is a growing interest in the concept of critical reflection in the adult learning and management literature. In this article, the author examines four different intellectual traditions that inform the use of the term "critical reflection" on the different ideals they express and the different definitions of critical reflection they use. On…

Derivation of the Ideal Gas Law

ERIC Educational Resources Information Center

Laugier, Alexander; Garai, Jozsef

2007-01-01

Undergraduate and graduate physics and chemistry books usually state that combining the gas laws results in the ideal gas law. Leaving the derivation to the students implies that this should be a simple task, most likely a substitution. Boyle's law, Charles's law, and the Avogadro's principle are given under certain conditions; therefore, direct…

Developing Ideal Student and Residency Programs.

ERIC Educational Resources Information Center

Selvin, Gerald J.

1993-01-01

The Veterans Administration (VA) is a primary educator of optometry students, with each college of optometry being affiliated with at least one VA hospital. Ideally, fourth-year optometry students rotate through a specific VA facility for about 12 weeks. Guidelines are designed to provide optimum care in a rich learning environment. (MSE)

Layout and flow of dermatology clinics: principles from operations management.

PubMed

Wang, Jordan V

2018-04-15

Dermatology is a medical specialty that experiences high patient demand and long patient wait times. Dermatology clinics should look for ways to improve efficiency through the incorporation of principles from operations management. Addressing the layout and flow of a clinic can lead to operational efficiency. An ideal layout may lead to increased patient volume, satisfaction, and retention.

Fluorescence Spectra of Highlighter Inks

NASA Astrophysics Data System (ADS)

Birriel, Jennifer J.; King, Damon

2018-01-01

Fluorescence spectra excited by laser pointers have been the subject of several papers in TPT. These papers all describe a fluorescence phenomenon in which the reflected laser light undergoes a change in color: this color change results from the combination of some partially reflected laser light and additional colors generated by fluorescent emission. Here we examine the fluorescence spectra of highlighter inks using green and violet laser pointers. We use an RSpec Explorer spectrometer to obtain spectra and compare the emission spectra of blue, green, yellow, orange, pink, and purple highlighters. The website Compound Interest details the chemical composition of highlighter inks; in addition, the site discusses how some base dye colors can be combined to produce the variety commercially available colors. Spectra obtained in this study were qualitatively consistent with the Compound Interest site. We discuss similarities and differences between various highlighter colors and conclude with the relevance of such studies to physics students.

Reply to ``Comment on `Free surface Hele-Shaw flows around an obstacle: A random walk simulation' ''

NASA Astrophysics Data System (ADS)

Bogoyavlenskiy, Vladislav A.; Cotts, Eric J.

2007-09-01

As pointed out by Vasconcelos in his Comment, our computer simulations of Hele-Shaw flows around series of wedges differ from analytical solutions existing for this problem. We attribute the discrepancy to the notion that these analytical solutions correspond to ideal, steady-state flow regimes which are hardly applicable when a rigid obstacle interacts with a moving liquid-gas interface.

Research Highlights

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stern, S. Alan; Ennico, Kimberly; Gladstone, G. Randall

This collection contains two articles, "NASA's New Horizons Mission to Pluto" and the "Diversity of Chemistry and Geologic Processes Observed by the MSL/Chem Cam Laser Instrument in Gale Crater, Mars". These highlights describe how New Horizons came to be, how the spacecraft got to Pluto, and how the findings are challenging our understanding of ice worlds in the outer solar system; and the ChemCam, one of ten instrument packages on board the rover.

Research Highlights

DOE PAGES

Stern, S. Alan; Ennico, Kimberly; Gladstone, G. Randall; ...

2016-04-01

This collection contains two articles, "NASA's New Horizons Mission to Pluto" and the "Diversity of Chemistry and Geologic Processes Observed by the MSL/Chem Cam Laser Instrument in Gale Crater, Mars". These highlights describe how New Horizons came to be, how the spacecraft got to Pluto, and how the findings are challenging our understanding of ice worlds in the outer solar system; and the ChemCam, one of ten instrument packages on board the rover.

Numerical simulation of transient hypervelocity flow in an expansion tube

NASA Technical Reports Server (NTRS)

Jacobs, P. A.

1992-01-01

Several numerical simulations of the transient flow of helium in an expansion tube are presented in an effort to identify some of the basic mechanisms which cause the noisy test flows seen in experiments. The calculations were performed with an axisymmetric Navier-Stokes code based on a finite volume formulation and upwinding techniques. Although laminar flow and ideal bursting of the diaphragms was assumed, the simulations showed some of the important features seen in experiments. In particular, the discontinuity in tube diameter of the primary diaphragm station introduced a transverse perturbation to the expanding driver gas and this perturbation was seen to propagate into the test gas under some flow conditions. The disturbances seen in the test flow can be characterized as either small amplitude, low frequency noise possibly introduced during shock compression or large amplitude, high frequency noise associated with the passage of the reflected head of the unsteady expansion.

Measurement of blood flow from an assist ventricle by computation of pneumatic driving parameters.

PubMed

Qian, K X

1992-03-01

The measurement of blood flow from an assist ventricle is important but sometimes difficult in artificial heart experiments. Along with the development of a pneumatic cylinder-piston driver coupled with a ventricular assist device, a simplified method for measuring pump flow was established. From driving parameters such as the piston (or cylinder) displacement and air pressure, the pump flow could be calculated by the use of the equation of state for an ideal gas. The results of this method are broadly in agreement with electromagnetic and Doppler measurements.

Karl Jaspers on the disease entity: Kantian ideas and Weberian ideal types.

PubMed

Walker, Chris

2014-09-01

Jaspers' nosology is indebted to Immanuel Kant's theory of knowledge. He drew the distinction of form and content from the Transcendental Analytic of Kant's Critique of Pure Reason. The distinction is universal to all knowledge, including psychopathology. Individual experience is constituted by a form or category of the Understanding to give a determinate or knowable object classified into the generic type of a real disease entity. The application of form and content is limited by the boundaries of experience. Beyond this boundary are wholes whose conception requires Ideas of reason drawn from the Transcendental Dialectic. Wholes are regulated by Ideas of reason to give an object or schema of the Idea collected into ideal types of an ideal typical disease entity. Jaspers drew ideal types from Max Weber's social theory. He anticipated that, as knowledge advanced, ideal typical disease entities would become real disease entities. By 1920, this had been the destiny of general paralysis as knowledge of its neuropathology, serology and microbiology emerged. As he presented the final edition of General Psychopathology in 1946, Jaspers was anticipating the transition of schizophrenia from ideal typical to real disease entity. Almost 70 years later, with knowledge of its aetiology still unclear, schizophrenia remains marooned as an ideal typical disease entity - still awaiting that crucial advance! © The Author(s) 2014.

Predicting membrane flux decline from complex mixtures using flow-field flow fractionation measurements and semi-empirical theory.

PubMed

Pellegrino, J; Wright, S; Ranvill, J; Amy, G

2005-01-01

Flow-Field Flow Fractionation (FI-FFF) is an idealization of the cross flow membrane filtration process in that, (1) the filtration flux and crossflow velocity are constant from beginning to end of the device, (2) the process is a relatively well-defined laminar-flow hydrodynamic condition, and (3) the solutes are introduced as a pulse-input that spreads due to interactions with each other and the membrane in the dilute-solution limit. We have investigated the potential for relating FI-FFF measurements to membrane fouling. An advection-dispersion transport model was used to provide 'ideal' (defined as spherical, non-interacting solutes) solute residence time distributions (RTDs) for comparison with 'real' RTDs obtained experimentally at different cross-field velocities and solution ionic strength. An RTD moment analysis based on a particle diameter probability density function was used to extract "effective" characteristic properties, rather than uniquely defined characteristics, of the standard solute mixture. A semi-empirical unsteady-state, flux decline model was developed that uses solute property parameters. Three modes of flux decline are included: (1) concentration polarization, (2) cake buildup, and (3) adsorption on/in pores, We have used this model to test the hypothesis-that an analysis of a residence time distribution using FI-FFF can describe 'effective' solute properties or indices that can be related to membrane flux decline in crossflow membrane filtration. Constant flux filtration studies included the changes of transport hydrodynamics (solvent flux to solute back diffusion (J/k) ratios), solution ionic strength, and feed water composition for filtration using a regenerated cellulose ultrafiltration membrane. Tests of the modeling hypothesis were compared with experimental results from the filtration measurements using several correction parameters based on the mean and variance of the solute RTDs. The corrections used to modify the boundary layer

Low-flow frequency and flow-duration characteristics of selected streams in Alabama through March 2014

USGS Publications Warehouse

Feaster, Toby D.; Lee, Kathyrn G.

2017-08-28

Low-flow statistics are needed by water-resource engineers, planners, and managers to protect and manage the water resources of Alabama. The accuracy of these statistics is influenced by such factors as length of record and specific hydrologic conditions measured in those records. As such, it is generally recommended that flow statistics be updated about every 10 years to provide improved and representative low-flow characteristics. The previous investigation of low-flow characteristics for Alabama included data through September 1990. Since that time, Alabama has experienced several historic droughts highlighting the need to update the low-flow characteristics at U.S. Geological Survey streamgaging stations. Consequently, this investigation was undertaken in cooperation with a number of State and local agencies to update low-flow frequency and flow-duration statistics at 210 continuous-record streamgaging stations in Alabama and 67 stations from basins that are shared with surrounding States. The flow characteristics were computed on the basis of available data through March 2014.

Numerical Solutions for Supersonic Flow of an Ideal Gas Around Blunt Two-Dimensional Bodies

NASA Technical Reports Server (NTRS)

Fuller, Franklyn B.

1961-01-01

The method described is an inverse one; the shock shape is chosen and the solution proceeds downstream to a body. Bodies blunter than circular cylinders are readily accessible, and any adiabatic index can be chosen. The lower limit to the free-stream Mach number available in any case is determined by the extent of the subsonic field, which in turn depends upon the body shape. Some discussion of the stability of the numerical processes is given. A set of solutions for flows about circular cylinders at several Mach numbers and several values of the adiabatic index is included.

Analysis of local scale tree-atmosphere interaction on pollutant concentration in idealized street canyons and application to a real urban junction

NASA Astrophysics Data System (ADS)

Buccolieri, Riccardo; Salim, Salim Mohamed; Leo, Laura Sandra; Di Sabatino, Silvana; Chan, Andrew; Ielpo, Pierina; de Gennaro, Gianluigi; Gromke, Christof

2011-03-01

This paper first discusses the aerodynamic effects of trees on local scale flow and pollutant concentration in idealized street canyon configurations by means of laboratory experiments and Computational Fluid Dynamics (CFD). These analyses are then used as a reference modelling study for the extension a the neighbourhood scale by investigating a real urban junction of a medium size city in southern Italy. A comparison with previous investigations shows that street-level concentrations crucially depend on the wind direction and street canyon aspect ratio W/H (with W and H the width and the height of buildings, respectively) rather than on tree crown porosity and stand density. It is usually assumed in the literature that larger concentrations are associated with perpendicular approaching wind. In this study, we demonstrate that while for tree-free street canyons under inclined wind directions the larger the aspect ratio the lower the street-level concentration, in presence of trees the expected reduction of street-level concentration with aspect ratio is less pronounced. Observations made for the idealized street canyons are re-interpreted in real case scenario focusing on the neighbourhood scale in proximity of a complex urban junction formed by street canyons of similar aspect ratios as those investigated in the laboratory. The aim is to show the combined influence of building morphology and vegetation on flow and dispersion and to assess the effect of vegetation on local concentration levels. To this aim, CFD simulations for two typical winter/spring days show that trees contribute to alter the local flow and act to trap pollutants. This preliminary study indicates that failing to account for the presence of vegetation, as typically practiced in most operational dispersion models, would result in non-negligible errors in the predictions.

The Heat Capacity of Ideal Gases

ERIC Educational Resources Information Center

Scott, Robert L.

2006-01-01

The heat capacity of an ideal gas has been shown to be calculable directly by statistical mechanics if the energies of the quantum states are known. However, unless one makes careful calculations, it is not easy for a student to understand the qualitative results. Why there are maxima (and occasionally minima) in heat capacity-temperature curves…

Ideal gas behavior of a strongly coupled complex (dusty) plasma.

PubMed

Oxtoby, Neil P; Griffith, Elias J; Durniak, Céline; Ralph, Jason F; Samsonov, Dmitry

2013-07-05

In a laboratory, a two-dimensional complex (dusty) plasma consists of a low-density ionized gas containing a confined suspension of Yukawa-coupled plastic microspheres. For an initial crystal-like form, we report ideal gas behavior in this strongly coupled system during shock-wave experiments. This evidence supports the use of the ideal gas law as the equation of state for soft crystals such as those formed by dusty plasmas.

Palæomagnetism of Hawaiian lava flows

USGS Publications Warehouse

Doell, Richard R.; Cox, Allan

1961-01-01

PALÆOMAGNETIC investigations of volcanic rocks extruded in various parts of the world during the past several million years have generally revealed a younger sequence of lava flows magnetized nearly parallel to the field of a theoretical geocentric axial dipole, underlain by a sequence of older flows with exactly the opposite direction of remanent magnetization. A 180-degree reversal of the geomagnetic field, occurring near the middle of the Pleistocene epoch, has been inferred by many workers from such results1–3. This is a preliminary report of an investigation of 755 oriented samples collected from 152 lava flows on the island of Hawaii, selected to represent as many stratigraphic horizons as possible. (Sampling details are indicated in Table 1.) This work was undertaken because Hawaii's numerous thick sequences of lava flows, previously mapped as Pliocene to Historic by Stearns and Macdonald4, and afterwards assigned ages ranging from later Tertiary to Recent, by Macdonald and Davis5, appeared to offer an ideal opportunity to examine the most recent reversal of Earth's field.

Collegiate Athletics Highlights.

ERIC Educational Resources Information Center

St. John, Eric

1999-01-01

Highlights 15 trends/events in black college athletics, including championship coaches, Black Coaches Association, eligibility issues, disclosure of athlete graduation rates, athletics resource allocation, early adoption of professional athlete status, success of the Women's National Basketball Association, lack of black access to certain sports,…

Individual deals within teams: Investigating the role of relative i-deals for employee performance.

PubMed

Vidyarthi, Prajya R; Singh, Satvir; Erdogan, Berrin; Chaudhry, Anjali; Posthuma, Richard; Anand, Smriti

2016-11-01

The authors extend i-deals theory to an individual-within-a-team context. Drawing upon social comparison theory, they contend that individuals will react to their own i-deals within the context of group members' i-deals. Therefore, they examine the role of relative i-deals (an individual's i-deals relative to the team's average) in relation to employee performance. Furthermore, integrating social comparison theory with social identity theory the authors assert that the behavioral outcomes of relative i-deals are influenced by the team's social and structural attributes of team orientation and task interdependence. Finally, they contend that the perceptions of one's relative standing with the leader, or leader-member exchange social comparison (LMXSC), mediate the i-deals-outcome relationship in groups with low team orientation and task interdependence. Results of multilevel modeling using time-lagged data from 321 employees nested in 46 teams demonstrated that the positive relationship between relative i-deals and employee performance was stronger in groups with low team orientation and task interdependence, and the mediation effect of LMXSC was stronger in teams with low rather than high team orientation. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Qualifications of an Ideal Teacher According to Social Studies Preservice Teachers

ERIC Educational Resources Information Center

Gencturk, Ebru; Akbas, Yavuz; Kaymakci, Selahattin

2012-01-01

In this study, the question of what kind of qualifications an ideal social studies teacher has tried to be investigated. For this purpose, freshman social studies preservice teachers' perceptions about the concept of "ideal teacher" were explored. This study was designed with document analysis, one of the methods of qualitative approach.…

Bayesian Ideal Types: Integration of Psychometric Data for Visually Impaired Persons.

ERIC Educational Resources Information Center

Jones, W. P.

1991-01-01

A model is proposed for the clinical synthesis of data from psychological tests of persons with visual impairments. The model integrates the concepts of the ideal type and Bayesian probability and compares actual test scores with ideal scores through use of a pattern similarity coefficient. A pilot study with Business Enterprise Program operators…

An ideal observer analysis of visual working memory.

PubMed

Sims, Chris R; Jacobs, Robert A; Knill, David C

2012-10-01

Limits in visual working memory (VWM) strongly constrain human performance across many tasks. However, the nature of these limits is not well understood. In this article we develop an ideal observer analysis of human VWM by deriving the expected behavior of an optimally performing but limited-capacity memory system. This analysis is framed around rate-distortion theory, a branch of information theory that provides optimal bounds on the accuracy of information transmission subject to a fixed information capacity. The result of the ideal observer analysis is a theoretical framework that provides a task-independent and quantitative definition of visual memory capacity and yields novel predictions regarding human performance. These predictions are subsequently evaluated and confirmed in 2 empirical studies. Further, the framework is general enough to allow the specification and testing of alternative models of visual memory (e.g., how capacity is distributed across multiple items). We demonstrate that a simple model developed on the basis of the ideal observer analysis-one that allows variability in the number of stored memory representations but does not assume the presence of a fixed item limit-provides an excellent account of the empirical data and further offers a principled reinterpretation of existing models of VWM. PsycINFO Database Record (c) 2012 APA, all rights reserved.

An Ideal Observer Analysis of Visual Working Memory

PubMed Central

Sims, Chris R.; Jacobs, Robert A.; Knill, David C.

2013-01-01

Limits in visual working memory (VWM) strongly constrain human performance across many tasks. However, the nature of these limits is not well understood. In this paper we develop an ideal observer analysis of human visual working memory, by deriving the expected behavior of an optimally performing, but limited-capacity memory system. This analysis is framed around rate–distortion theory, a branch of information theory that provides optimal bounds on the accuracy of information transmission subject to a fixed information capacity. The result of the ideal observer analysis is a theoretical framework that provides a task-independent and quantitative definition of visual memory capacity and yields novel predictions regarding human performance. These predictions are subsequently evaluated and confirmed in two empirical studies. Further, the framework is general enough to allow the specification and testing of alternative models of visual memory (for example, how capacity is distributed across multiple items). We demonstrate that a simple model developed on the basis of the ideal observer analysis—one which allows variability in the number of stored memory representations, but does not assume the presence of a fixed item limit—provides an excellent account of the empirical data, and further offers a principled re-interpretation of existing models of visual working memory. PMID:22946744

No Surgical Innovation Without Evaluation: Evolution and Further Development of the IDEAL Framework and Recommendations.

PubMed

Hirst, Allison; Philippou, Yiannis; Blazeby, Jane; Campbell, Bruce; Campbell, Marion; Feinberg, Joshua; Rovers, Maroeska; Blencowe, Natalie; Pennell, Christopher; Quinn, Tom; Rogers, Wendy; Cook, Jonathan; Kolias, Angelos G; Agha, Riaz; Dahm, Philipp; Sedrakyan, Art; McCulloch, Peter

2018-04-24

To update, clarify, and extend IDEAL concepts and recommendations. New surgical procedures, devices, and other complex interventions need robust evaluation for safety, efficacy, and effectiveness. Unlike new medicines, there is no internationally agreed evaluation pathway for generating and analyzing data throughout the life cycle of surgical innovations. The IDEAL Framework and Recommendations were designed to provide this pathway and they have been used increasingly since their introduction in 2009. Based on a Delphi survey, expert workshop and major discussions during IDEAL conferences held in Oxford (2016) and New York (2017), this article updates and extends the IDEAL Recommendations, identifies areas for future research, and discusses the ethical problems faced by investigators at each IDEAL stage. The IDEAL Framework describes 5 stages of evolution for new surgical therapeutic interventions-Idea, Development, Exploration, Assessment, and Long-term Study. This comprehensive update proposes several modifications. First, a "Pre-IDEAL" stage describing preclinical studies has been added. Second we discuss potential adaptations to expand the scope of IDEAL (originally designed for surgical procedures) to accommodate therapeutic devices, through an IDEAL-D variant. Third, we explicitly recognise the value of comprehensive data collection through registries at all stages in the Framework and fourth, we examine the ethical issues that arise at each stage of IDEAL and underpin the recommendations. The Recommendations for each stage are reviewed, clarified and additional detail added. The intention of this article is to widen the practical use of IDEAL by clarifying the rationale for and practical details of the Recommendations. Additional research based on the experience of implementing these Recommendations is needed to further improve them.

Low Reynolds number flow near tiny leaves, stems, and trichomes

NASA Astrophysics Data System (ADS)

Strickland, Christopher; Pasour, Virginia; Miller, Laura

2016-11-01

In terrestrial and aquatic environments such as forest canopies, grass fields, and seagrass beds, the density and shape of trunks, branches, stems, leaves and trichomes (the hairs or fine outgrowths on plants) can drastically alter both the average wind speed and profile through these environments and near each plant. While many studies of flow in these environments have focused on bulk properties of the flow at scales on the order of meters, the low Reynolds number flow close to vegetative structures is especially complex and relevant to nutrient exchange. Using three-dimensional immersed boundary simulations, we resolve the flow around trichomes and small leaves and quantify velocities, shear stresses, and mixing while varying the height and density of idealized structures. National Science Foundation Grant DMS-1127914 to the Statistical and Applied Mathematical Sciences Institute, and the Army Research Office.

Exploring the Professional Ideals of Christian Teachers from Conservative Protestant Schools in the Netherlands

ERIC Educational Resources Information Center

Boele-de Bruin, H. L.; de Muynck, A.

2018-01-01

Professional ideals arise from personal worldviews and specify teachers' professional identities. This study aimed to explore how faith is present in the professional ideals of Christian teachers. The professional ideals of 107 Dutch teachers from conservative Protestant primary and secondary schools were explored using an open-ended…

Solution adaptive grids applied to low Reynolds number flow

NASA Astrophysics Data System (ADS)

de With, G.; Holdø, A. E.; Huld, T. A.

2003-08-01

A numerical study has been undertaken to investigate the use of a solution adaptive grid for flow around a cylinder in the laminar flow regime. The main purpose of this work is twofold. The first aim is to investigate the suitability of a grid adaptation algorithm and the reduction in mesh size that can be obtained. Secondly, the uniform asymmetric flow structures are ideal to validate the mesh structures due to mesh refinement and consequently the selected refinement criteria. The refinement variable used in this work is a product of the rate of strain and the mesh cell size, and contains two variables Cm and Cstr which determine the order of each term. By altering the order of either one of these terms the refinement behaviour can be modified.

Calculations of unsteady turbulent boundary layers with flow reversal

NASA Technical Reports Server (NTRS)

Nash, J. F.; Patel, V. C.

1975-01-01

The results are presented of a series of computational experiments aimed at studying the characteristics of time-dependent turbulent boundary layers with embedded reversed-flow regions. A calculation method developed earlier was extended to boundary layers with reversed flows for this purpose. The calculations were performed for an idealized family of external velocity distributions, and covered a range of degrees of unsteadiness. The results confirmed those of previous studies in demonstrating that the point of flow reversal is nonsingular in a time-dependent boundary layer. A singularity was observed to develop downstream of reversal, under certain conditions, accompanied by the breakdown of the boundary-layer approximations. A tentative hypothesis was advanced in an attempt to predict the appearance of the singularity, and is shown to be consistent with the calculated results.

Editorial highlighting and highly cited papers

NASA Astrophysics Data System (ADS)

Antonoyiannakis, Manolis

Editorial highlighting-the process whereby journal editors select, at the time of publication, a small subset of papers that are ostensibly of higher quality, importance or interest-is by now a widespread practice among major scientific journal publishers. Depending on the venue, and the extent to which editorial resources are invested in the process, highlighted papers appear as News & Views, Research Highlights, Perspectives, Editors' Choice, IOP Select, Editors' Summary, Spotlight on Optics, Editors' Picks, Viewpoints, Synopses, Editors' Suggestions, etc. Here, we look at the relation between highlighted papers and highly influential papers, which we define at two levels: having received enough citations to be among the (i) top few percent of their journal, and (ii) top 1% of all physics papers. Using multiple linear regression and multilevel regression modeling we examine the parameters associated with highly influential papers. We briefly comment on cause and effect relationships between citedness and highlighting of papers.

The Role of Idealization in Science and Its Implications for Science Education

NASA Astrophysics Data System (ADS)

Niaz, Mansoor

1999-06-01

The main objective of this article is to study the role of empirical evidence in the interpretation of psychological and epistemological aspects of Piagetian theory. According to Galilean methodology, after having asked the right question, a scientist could experimentally vary one impediment, and observe what happens to the dependent variable, as it approaches the ideal limiting case. Following Galileo's idealization, scientific laws being epistemological constructions do not describe the behavior of actual bodies. It is plausible to suggest that just as Galileo's ideal law can be observed only when all the impediment variables approach zero, similarly individuals in the real world have various `impediments' and it is only when these impediments are gradually removed by experimental manipulation that the real performance of individuals can approximate the competence of Piaget's epistemic subject (ideal knower). Finally, evidence is presented to the effect that by experimentally manipulating the impediment variables (e.g., Pascual-Leone's M-demand and Witkin's perceptual field effect of a task), performance of the real subjects approximates the competence of the ideal epistemic subject, which leads to the construction of a neo-Piagetian epistemological theory.

Kelvin-Helmholtz versus Hall magnetoshear instability in astrophysical flows.

PubMed

Gómez, Daniel O; Bejarano, Cecilia; Mininni, Pablo D

2014-05-01

We study the stability of shear flows in a fully ionized plasma. Kelvin-Helmholtz is a well-known macroscopic and ideal shear-driven instability. In sufficiently low-density plasmas, also the microscopic Hall magnetoshear instability can take place. We performed three-dimensional simulations of the Hall-magnetohydrodynamic equations where these two instabilities are present, and carried out a comparative study. We find that when the shear flow is so intense that its vorticity surpasses the ion-cyclotron frequency of the plasma, the Hall magnetoshear instability is not only non-negligible, but it actually displays growth rates larger than those of the Kelvin-Helmholtz instability.

Properties of an ideal PET perfusion tracer: new PET tracer cases and data.

PubMed

Maddahi, Jamshid

2012-02-01

An ideal positron emission tomography (PET) tracer should be highly extractable by the myocardium and able to provide high-resolution images, should enable quantification of absolute myocardial blood flow (MBF), should be compatible with both pharmacologically induced and exercise-induced stress imaging, and should not require an on-site cyclotron. The PET radionuclides nitrogen-13 ammonia and oxygen-15 water require an on-site cyclotron. Rubidium-82 may be available locally due to the generator source, but greater utilization is limited because of its relatively low myocardial extraction fraction, long positron range, and generator cost. Flurpiridaz F 18, a novel PET tracer in development, has a high-extraction fraction, short positron range, and relatively long half-life (as compared to currently available tracers), and may be produced at regional cyclotrons. Results of early clinical trials suggest that both pharmacologically and exercise-induced stress PET imaging protocols can be completed more rapidly and with lower patient radiation exposure than with single-photon emission computerized tomography (SPECT) tracers. As compared to SPECT images in the same patients, flurpiridaz F 18 PET images showed better defect contrast. Flurpiridaz F 18 is a potentially promising tracer for assessment of myocardial perfusion, measurement of absolute MBF, calculation of coronary flow reserves, and assessment of cardiac function at the peak of the stress response.

Volumetric blood flow via time-domain correlation: experimental verification.

PubMed

Embree, P M; O'Brien, W R

1990-01-01

A novel ultrasonic volumetric flow measurement method using time-domain correlation of consecutive pairs of echoes has been developed. An ultrasonic data acquisition system determined the time shift between a pair of range gated echoes by searching for the time shift with the maximum correlation between the RF sampled waveforms. Experiments with a 5-MHz transducer indicate that the standard deviation of the estimate of steady fluid velocity through 6-mm-diameter tubes is less than 10% of the mean. Experimentally, Sephadex (G-50; 20-80 mum dia.) particles in water and fresh porcine blood have been used as ultrasound scattering fluids. Two-dimensional (2-D) flow velocity can be estimated by slowly sweeping the ultrasonic beam across the blood vessel phantom. Volumetric flow through the vessel is estimated by integrating the 2-D flow velocity field and then is compared to hydrodynamic flow measurements to assess the overall experimental accuracy of the time-domain method. Flow rates from 50-500 ml/min have been estimated with an accuracy better than 10% under the idealized characteristics used in this study, which include straight circular thin-walled tubes, laminar axially-symmetric steady flow, and no intervening tissues.

Nitrate Removal Rates in Denitrifying Bioreactors During Storm Flows

NASA Astrophysics Data System (ADS)

Pluer, W.; Walter, T.

2017-12-01

Field denitrifying bioreactors are designed to reduce excess nitrate (NO3-) pollution in runoff from agricultural fields. Field bioreactors saturate organic matter to create conditions that facilitate microbial denitrification. Prior studies using steady flow in lab-scale bioreactors showed that a hydraulic retention time (HRT) between 4 and 10 hours was optimal for reducing NO3- loads. However, during storm-induced events, flow rate and actual HRT fluctuate. These fluctuations have the potential to disrupt the system in significant ways that are not captured by the idealized steady-flow HRT models. The goal of this study was to investigate removal rate during dynamic storm flows of variable rates and durations. Our results indicate that storm peak flow and duration were not significant controlling variables. Instead, we found high correlations (p=0.004) in average removal rates between bioreactors displaying a predominantly uniform flow pattern compared with bioreactors that exhibited preferential flow (24.4 and 21.4 g N m-3 d-1, respectively). This suggests that the internal flow patterns are a more significant driver of removal rate than external factors of the storm hydrograph. Designing for flow patterns in addition to theoretical HRT will facilitate complete mixing within the bioreactors. This will help maximize excess NO3- removal during large storm-induced runoff events.

Modeling of flow-dominated MHD instabilities at WiPPAL using NIMROD

NASA Astrophysics Data System (ADS)

Flanagan, K.; McCollam, K. J.; Milhone, J.; Mirnov, V. V.; Nornberg, M. D.; Peterson, E. E.; Siller, R.; Forest, C. B.

2017-10-01

Using the NIMROD (non-ideal MHD with rotation - open discussion) code developed at UW-Madison, we model two different flow scenarios to study the onset of MHD instabilities in flow-dominated plasmas in the Big Red Ball (BRB) and the Plasma Couette Experiment (PCX). Both flows rely on volumetric current drive, where a large current is drawn through the plasma across a weak magnetic field, injecting J × B torque across the whole volume. The first scenario uses a vertical applied magnetic field and a mostly radial injected current to create Couette-like flows which may excite the magnetorotational instability (MRI). In the other scenario, a quadrupolar field is applied to create counter-rotating von Karman-like flow that demonstrates a dynamo-like instability. For both scenarios, the differences between Hall and MHD Ohm's laws are explored. The implementation of BRB geometry in NIMROD, details of the observed flows, and instability results are shown. This work was funded by DoE and NSF.

An ideal sealed source life-cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tompkins, Joseph Andrew

2009-01-01

system they we have today. This regulation created a new regulatory framework seen as promising at the time. However, now they recognize that, despite the good intentions, the NIJWP/85 has not solved any source disposition problems. The answer to these sealed source disposition problems is to adopt a philosophy to correct these regulatory issues, determine an interim solution, execute that solution until there is a minimal backlog of sources to deal with, and then let the mechanisms they have created solve this problem into the foreseeable future. The primary philosophical tenet of the ideal sealed source life cycle follows. You do not allow the creation (or importation) of any source whose use cannot be justified, which cannot be affordably shipped, or that does not have a well-delinated and affordable disposition pathway. The path forward dictates that we fix the problem by embracing the Ideal Source Life cycle. In figure 1, we can see some of the elements of the ideal source life cycle. The life cycle is broken down into four portions, manufacture, use, consolidation, and disposition. These four arbitrary elements allow them to focus on the ideal life cycle phases that every source should go through between manufacture and final disposition. As we examine the various phases of the sealed source life cycle, they pick specific examples and explore the adoption of the ideal life cycle model.« less

Soil Contamination, Advanced integrated characterisation and time-lapse Monitoring, SoilCAM project highlights

NASA Astrophysics Data System (ADS)

French, H. K.; Van Der Zee, S. E.; Wehrer, M.; Godio, A.; Pedersen, L. B.; Tsocano, G.

2013-12-01

measurements indicate where the remaining crude oil can be found. Water samples from multilevel samplers reveal crude oil present in emulsion in the zone of groundwater fluctuations, highlighting the importance of colloidal transport. Modelling of multiphase flow of the fluctuating groundwater level explains the lack of horizontal displacement of the plume in the area. Geochemistry of the groundwater clearly indicates degradation of hydrocarbons under iron- and sulphate reducing conditions, but changes were too slow to be mapped by time-lapse geophysical measurements during the project period. MODFLOW was used to simulate the regional groundwater flow and transport in the area. Highlights of the results from both test sites will be presented as an integrated overview. Snow removal at Oslo airport

American Citizens’ Views of an Ideal Pig Farm

PubMed Central

Sato, Patrycia; Hötzel, Maria J.; von Keyserlingk, Marina A.G.

2017-01-01

Simple Summary The public, who also make up the largest proportion of consumers of animal products, often criticize farm animal industries in regards to their care and handling of farm animals. The U.S. swine industry has not been exempt from such criticisms. The aim of this study was to explore the views of the people not affiliated with the swine industry on what they perceived to be the ideal pig/pork farm, and their associated reasons. Through an online survey, participants were invited to respond to the following open-ended question: “What do you consider to be an ideal pig/pork farm and why are these characteristics important to you?”. Respondents considered animal care, profitability, farm size, compliance with sanitary, environmental rules and regulations, farm cleanliness and sanitary standards, and workers’ rights and welfare important, but also raised concerns relating to pigs’ quality of life including space to move, feeding, contact with outdoors or nature, absence of pain, suffering and mistreatment. Perspectives were also raised regarding the ideal farm as a profitable business operation, clean, and with optimal sanitary conditions. Respondents also emphasized naturalness, frequently stating that pigs should have access to the outdoors, and rejected the use of hormones, antibiotics, and other chemicals for the purposes of increasing production. Abstract Food animal production practices are often cited as having negative animal welfare consequences. The U.S. swine industry has not been exempt from such criticisms. Little is known, however, about how lay citizens who are not actively engaged in agricultural discussions, think about swine production. Thus, the aim of this study was to explore the views of people not affiliated with the swine industry on what they perceived to be the ideal pig/pork farm, and their associated reasons. Through an online survey, participants were invited to respond to the following open-ended question: “What do

Differential molar heat capacities to test ideal solubility estimations.

PubMed

Neau, S H; Bhandarkar, S V; Hellmuth, E W

1997-05-01

Calculation of the ideal solubility of a crystalline solute in a liquid solvent requires knowledge of the difference in the molar heat capacity at constant pressure of the solid and the supercooled liquid forms of the solute, delta Cp. Since this parameter is not usually known, two assumptions have been used to simplify the expression. The first is that delta Cp can be considered equal to zero; the alternate assumption is that the molar entropy of fusion, delta Sf, is an estimate of delta Cp. Reports claiming the superiority of one assumption over the other, on the basis of calculations done using experimentally determined parameters, have appeared in the literature. The validity of the assumptions in predicting the ideal solubility of five structurally unrelated compounds of pharmaceutical interest, with melting points in the range 420 to 470 K, was evaluated in this study. Solid and liquid heat capacities of each compound near its melting point were determined using differential scanning calorimetry. Linear equations describing the heat capacities were extrapolated to the melting point to generate the differential molar heat capacity. Linear data were obtained for both crystal and liquid heat capacities of sample and test compounds. For each sample, ideal solubility at 298 K was calculated and compared to the two estimates generated using literature equations based on the differential molar heat capacity assumptions. For the compounds studied, delta Cp was not negligible and was closer to delta Sf than to zero. However, neither of the two assumptions was valid for accurately estimating the ideal solubility as given by the full equation.

Theory and Simulation of Real and Ideal Magnetohydrodynamic Turbulence

NASA Technical Reports Server (NTRS)

Shebalin, John V.

2004-01-01

Incompressible, homogeneous magnetohydrodynamic (MHD) turbulence consists of fluctuating vorticity and magnetic fields, which are represented in terms of their Fourier coefficients. Here, a set of five Fourier spectral transform method numerical simulations of two-dimensional (2-D) MHD turbulence on a 512(sup 2) grid is described. Each simulation is a numerically realized dynamical system consisting of Fourier modes associated with wave vectors k, with integer components, such that k = |k| less than or equal to k(sub max). The simulation set consists of one ideal (non-dissipative) case and four real (dissipative) cases. All five runs had equivalent initial conditions. The dimensions of the dynamical systems associated with these cases are the numbers of independent real and imaginary parts of the Fourier modes. The ideal simulation has a dimension of 366104, while each real simulation has a dimension of 411712. The real runs vary in magnetic Prandtl number P(sub M), with P(sub M) is a member of {0.1, 0.25, 1, 4}. In the results presented here, all runs have been taken to a simulation time of t = 25. Although ideal and real Fourier spectra are quite different at high k, they are similar at low values of k. Their low k behavior indicates the existence of broken symmetry and coherent structure in real MHD turbulence, similar to what exists in ideal MHD turbulence. The value of PM strongly affects the ratio of kinetic to magnetic energy and energy dissipation (which is mostly ohmic). The relevance of these results to 3-D Navier-Stokes and MHD turbulence is discussed.

A Multidimensional Ideal Point Item Response Theory Model for Binary Data

ERIC Educational Resources Information Center

Maydeu-Olivares, Albert; Hernandez, Adolfo; McDonald, Roderick P.

2006-01-01

We introduce a multidimensional item response theory (IRT) model for binary data based on a proximity response mechanism. Under the model, a respondent at the mode of the item response function (IRF) endorses the item with probability one. The mode of the IRF is the ideal point, or in the multidimensional case, an ideal hyperplane. The model…

40 CFR 1065.645 - Amount of water in an ideal gas.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Amount of water in an ideal gas. 1065.645 Section 1065.645 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.645 Amount of water in an ideal gas. This section describes how to...

40 CFR 1065.645 - Amount of water in an ideal gas.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Amount of water in an ideal gas. 1065.645 Section 1065.645 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.645 Amount of water in an ideal gas. This section describes how to...

40 CFR 1065.645 - Amount of water in an ideal gas.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Amount of water in an ideal gas. 1065.645 Section 1065.645 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.645 Amount of water in an ideal gas. This section describes how to...

Using Highlighting to Train Attentional Expertise

PubMed Central

Roads, Brett; Mozer, Michael C.; Busey, Thomas A.

2016-01-01

Acquiring expertise in complex visual tasks is time consuming. To facilitate the efficient training of novices on where to look in these tasks, we propose an attentional highlighting paradigm. Highlighting involves dynamically modulating the saliency of a visual image to guide attention along the fixation path of a domain expert who had previously viewed the same image. In Experiment 1, we trained naive subjects via attentional highlighting on a fingerprint-matching task. Before and after training, we asked subjects to freely inspect images containing pairs of prints and determine whether the prints matched. Fixation sequences were automatically scored for the degree of expertise exhibited using a Bayesian discriminative model of novice and expert gaze behavior. Highlighted training causes gaze behavior to become more expert-like not only on the trained images but also on transfer images, indicating generalization of learning. In Experiment 2, to control for the possibility that the increase in expertise is due to mere exposure, we trained subjects via highlighting of fixation sequences from novices, not experts, and observed no transition toward expertise. In Experiment 3, to determine the specificity of the training effect, we trained subjects with expert fixation sequences from images other than the one being viewed, which preserves coarse-scale statistics of expert gaze but provides no information about fine-grain features. Observing at least a partial transition toward expertise, we obtain only weak evidence that the highlighting procedure facilitates the learning of critical local features. We discuss possible improvements to the highlighting procedure. PMID:26744839

Using Highlighting to Train Attentional Expertise.

PubMed

Roads, Brett; Mozer, Michael C; Busey, Thomas A

2016-01-01

Acquiring expertise in complex visual tasks is time consuming. To facilitate the efficient training of novices on where to look in these tasks, we propose an attentional highlighting paradigm. Highlighting involves dynamically modulating the saliency of a visual image to guide attention along the fixation path of a domain expert who had previously viewed the same image. In Experiment 1, we trained naive subjects via attentional highlighting on a fingerprint-matching task. Before and after training, we asked subjects to freely inspect images containing pairs of prints and determine whether the prints matched. Fixation sequences were automatically scored for the degree of expertise exhibited using a Bayesian discriminative model of novice and expert gaze behavior. Highlighted training causes gaze behavior to become more expert-like not only on the trained images but also on transfer images, indicating generalization of learning. In Experiment 2, to control for the possibility that the increase in expertise is due to mere exposure, we trained subjects via highlighting of fixation sequences from novices, not experts, and observed no transition toward expertise. In Experiment 3, to determine the specificity of the training effect, we trained subjects with expert fixation sequences from images other than the one being viewed, which preserves coarse-scale statistics of expert gaze but provides no information about fine-grain features. Observing at least a partial transition toward expertise, we obtain only weak evidence that the highlighting procedure facilitates the learning of critical local features. We discuss possible improvements to the highlighting procedure.

Toward an Ideal Senior High School Governance Structure.

ERIC Educational Resources Information Center

Treslan, D. L.

1979-01-01

This paper delineates six attributes of an ideal high school governance structure: respect, freedom, rationality, flexibility, equality, and involvement of staff and students in the decision-making process. (Author/SJL)

Ideal for Whom? A Cultural Analysis of Ideal Worker Norms in Higher Education and Student Affairs Graduate Programs

ERIC Educational Resources Information Center

Sallee, Margaret W.

2016-01-01

This chapter explores the consequences of ideal worker norms for graduate student-parents in higher education and student affairs programs. Using Schein's (2004) levels of culture as a conceptual lens, this chapter considers the ways that programmatic structures and interactions with faculty and peers reflect and reproduce a culture across…

The NCOREL computer program for 3D nonlinear supersonic potential flow computations

NASA Technical Reports Server (NTRS)

Siclari, M. J.

1983-01-01

An innovative computational technique (NCOREL) was established for the treatment of three dimensional supersonic flows. The method is nonlinear in that it solves the nonconservative finite difference analog of the full potential equation and can predict the formation of supercritical cross flow regions, embedded and bow shocks. The method implicitly computes a conical flow at the apex (R = 0) of a spherical coordinate system and uses a fully implicit marching technique to obtain three dimensional cross flow solutions. This implies that the radial Mach number must remain supersonic. The cross flow solutions are obtained by using type dependent transonic relaxation techniques with the type dependency linked to the character of the cross flow velocity (i.e., subsonic/supersonic). The spherical coordinate system and marching on spherical surfaces is ideally suited to the computation of wing flows at low supersonic Mach numbers due to the elimination of the subsonic axial Mach number problems that exist in other marching codes that utilize Cartesian transverse marching planes.

NASA Langley Highlights, 1997

NASA Technical Reports Server (NTRS)

1998-01-01

Langley's mission is accomplished by performing innovative research relevant to national needs and Agency goals, transferring technology to users in a timely manner, and providing development support to other United States Government Agencies, industry, other NASA Centers, the educational community, and the local community. This report contains highlights of some of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year. The highlights illustrate the broad range of research and technology activities carried out by NASA Langley Research Center and the contributions of this work toward maintaining United States' leadership in aeronautics and space research.

Ideal walking dynamics via a gauged NJL model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rantaharju, Jarno; Pica, Claudio; Sannino, Francesco

According to the ideal walking technicolor paradigm, large mass anomalous dimensions arise in gauged Nambu–Jona-Lasinio (NJL) models when the four-fermion coupling is sufficiently strong to induce spontaneous symmetry breaking in an otherwise conformal gauge theory. Therefore, we study the SU(2) gauged NJL model with two adjoint fermions using lattice simulations. The model is in an infrared conformal phase at small NJL coupling while it displays a chirally broken phase at large NJL couplings. In the infrared conformal phase, we find that the mass anomalous dimension varies with the NJL coupling, reaching γm ~ 1 close to the chiral symmetry breakingmore » transition, de facto making the present model the first explicit realization of the ideal walking scenario.« less

Ideal walking dynamics via a gauged NJL model

DOE PAGES

Rantaharju, Jarno; Pica, Claudio; Sannino, Francesco

2017-07-25

According to the ideal walking technicolor paradigm, large mass anomalous dimensions arise in gauged Nambu–Jona-Lasinio (NJL) models when the four-fermion coupling is sufficiently strong to induce spontaneous symmetry breaking in an otherwise conformal gauge theory. Therefore, we study the SU(2) gauged NJL model with two adjoint fermions using lattice simulations. The model is in an infrared conformal phase at small NJL coupling while it displays a chirally broken phase at large NJL couplings. In the infrared conformal phase, we find that the mass anomalous dimension varies with the NJL coupling, reaching γm ~ 1 close to the chiral symmetry breakingmore » transition, de facto making the present model the first explicit realization of the ideal walking scenario.« less

Hyperpolarized (129) Xe imaging of the rat lung using spiral IDEAL.

PubMed

Doganay, Ozkan; Wade, Trevor; Hegarty, Elaine; McKenzie, Charles; Schulte, Rolf F; Santyr, Giles E

2016-08-01

To implement and optimize a single-shot spiral encoding strategy for rapid 2D IDEAL projection imaging of hyperpolarized (Hp) (129) Xe in the gas phase, and in the pulmonary tissue (PT) and red blood cells (RBCs) compartments of the rat lung, respectively. A theoretical and experimental point spread function analysis was used to optimize the spiral k-space read-out time in a phantom. Hp (129) Xe IDEAL images from five healthy rats were used to: (i) optimize flip angles by a Bloch equation analysis using measured kinetics of gas exchange and (ii) investigate the feasibility of the approach to characterize the exchange of Hp (129) Xe. A read-out time equal to approximately 1.8 × T2* was found to provide the best trade-off between spatial resolution and signal-to-noise ratio (SNR). Spiral IDEAL approaches that use the entire dissolved phase magnetization should give an SNR improvement of a factor of approximately three compared with Cartesian approaches with similar spatial resolution. The IDEAL strategy allowed imaging of gas, PT, and RBC compartments with sufficient SNR and temporal resolution to permit regional gas exchange measurements in healthy rats. Single-shot spiral IDEAL imaging of gas, PT and RBC compartments and gas exchange is feasible in rat lung using Hp (129) Xe. Magn Reson Med 76:566-576, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Ideal gender identity related to parent images and locus of control: Jungian and social learning perspectives.

PubMed

Shimoda, Hiroko; Keskinen, Soili

2004-06-01

In this research, we wanted to clarify how gender images are different or invariant and related to parents, attributes, and the attitude of controlling life (locus of control) in two cultural contexts, Japan and Finland. For this purpose, students' ideal gender images, consisting of ideal mother, female, father and male images, and parents' similarity to the four ideal gender images were studied in 135 Japanese and 119 Finnish university students. Major findings were (a) Japanese students' ideal gender images were more stereotypic than those of Finnish students; (b) students' ideal mother image and parents' similarity to the ideal mother image were related only to their sex, which supports Jung's theory; (c) students socially learned other ideal gender images, but these did not fit with expectation from social learning theory; (d) Japanese students' mothers are models or examples of gender images, but Finnish male students did not seem to base their ideal gender images on their parents. Implication of measures was discussed.

Do the Particles of an Ideal Gas Collide?

ERIC Educational Resources Information Center

Lesk, Arthur M.

1974-01-01

Describes the collisional properties as a logically essential component of the ideal gas model since an actual intraparticle process cannot support observable anisotropic velocity distributions without collisions taken into account. (CC)

STS-47 Mission Highlights Resource Tape

NASA Technical Reports Server (NTRS)

1992-01-01

The mission of the STS-47 flight is highlighted in this video. The flight crew consisted of: Cmdr. 'Hoot' Gibson, Pilot Kurt Brown, Payload Cmdr. Jan Davis, Payload Specialist. M. Mohri (Japanese Astronaut), and Mission Specialists Jay Apt and May Jemison. The primary goal of this mission was the set-up and carrying out of experiments in the accompanying Japanese Spacelab (SL-J) in cooperation with the Japanese Space Program. Dr. Mohri is the first professional Japanese astronaut to fly in space. Vice President Dan Quayle and his wife are shown addressing the astronauts of the Space Shuttle Endeavour with a small pre-launch speech. On this flight many different physical, physiological, and biological spaceborne experiments were performed. These experiments included: a gas evaporation in low gravity environment experiment; a brainwave signals from carp experiment; several human eye movement and visual physiological tests; various physiological tests on a variety of insects and frogs; a embryology experiments on tadpoles; several experiments concerned with fluid dynamics; an imaging furnace test with heated glass containing gold particles (flow measurement); a Solid Surface Combustion Experiment; and a protein crystal growth experiment. Launch, in-orbit, and landing footage is shown, along with a variety of crew activities. One feature that astronauts were able to videotape was the actual in-orbit movement of the side wing flaps of the Space Shuttle.

[The impact of exposure to images of ideally thin models on body dissatisfaction in young French and Italian women].

PubMed

Rodgers, R; Chabrol, H

2009-06-01

images of average-size models (F(1.32)=4.64, p=0.039). However, there was no significant difference between body dissatisfaction scores reported after exposure to images of average-size models accompanied by neutral or supportive slogans (F(1.39)=0.093, p=0.76). This study illustrates the negative effects of exposure to thin-ideal media images among students with body dissatisfaction. The use of average-size models in the media and advertising might help reduce these effects. No improvement was obtained via the use of a supportive slogan. These results highlight the importance of media literacy campaigns in the prevention of eating disorders.

Flowing with the changing needs of hydrogeology instruction

NASA Astrophysics Data System (ADS)

Gleeson, T.; Allen, D. M.; Ferguson, G.

2012-01-01

Hydrogeology is now taught in a broad spectrum of departments and institutions to students with diverse backgrounds. Successful instruction in hydrogeology thus requires a variety of pedagogical approaches depending on desired learning outcomes and the diverse background of students. We review the pedagogical literature in hydrogeology to highlight recent advances and analyze a 2005 survey of 68 hydrogeology instructors. The literature and survey results suggest there are ~15 topics that are considered crucial by most hydrogeologists and >100 other topics that are considered crucial by some hydrogeologists. The crucial topics focus on properties of aquifers and fundamentals of groundwater flow, and should likely be part of all undergraduate hydrogeology courses. Other topics can supplement and support these crucial topics, depending on desired learning outcomes. Classroom settings continue to provide a venue for emphasizing fundamental knowledge. However, recent pedagogical advances are biased towards field and laboratory instruction with a goal of bolstering experiential learning. Field methods build on the fundamentals taught in the classroom and emphasize the collection of data, data uncertainty, and the development of vocational skills. Laboratory and computer-based exercises similarly build on theory, and offer an opportunity for data analysis and integration. The literature suggests curricula at all levels should ideally balance field, laboratory, and classroom pedagogy into an iterative and integrative whole. An integrated approach leads to greater student motivation and advancement of theoretical and vocational knowledge.

Changes in blood flow due to stented parent artery expansion in an intracranial aneurysm.

PubMed

Mori, Futoshi; Ohta, Makoto; Matsuzawa, Teruo

2015-01-01

Stent placement is thought to obstruct the inflow of blood to an aneurysm. However, we introduced parent artery expansion and demonstrated that this may reduce the blood flow by the stent. In our previous study using idealized shapes, the results showed that flow reduction was greater than 22.2%, even if the expansion rate was only 6%. Furthermore, the parent artery expansion is predominantly caused by the effect of flow reduction as compared to that of flow reduction due to the obstruction of flow under stent placement. However, a realistic shape is complex and the blood flow also becomes complex flow. It is not understood whether the results of flow in the idealized shape are reflective of flow from a realistic 3D model. Therefore, we examined the effect of parent artery expansion using a realistic model. The aim is to clarify the effects of parent artery expansion on inflow rate, wall shear stress, and oscillatory shear index. We used a patient-specific geometry of a human internal carotid artery with an aneurysm. The geometry of parent artery expansion due to oversized stent constructed based on the voronoi diagram. We performed calculations in the unsteady-state situations using constructed models. The complexity of the flow in the aneurysm decreases in case of expanded parent artery. The inflow rate decreases by 33.6% immediately after parent artery expansion alone without a stent. The effect of the parent artery expansion on flow reduction is larger than that of the obstruction flow by stent placement. In addition, wall shear stress and oscillatory shear index on the aneurysm wall decrease by change in blood flow due to the parent artery expansion. The effects of the parent artery expansion in a realistic aneurysm model with different stent lengths were evaluated on the basis of a numerical simulation. Although the flow was complex, the parent artery expansion with stent reduces the inflow to the aneurysm and wall shear stress and oscillatory shear index on

Ideal cardiovascular health and psychosocial risk factors among Finnish female municipal workers.

PubMed

Veromaa, Veera; Kautiainen, Hannu; Saxen, Ulla; Malmberg-Ceder, Kirsi; Bergman, Elina; Korhonen, Päivi E

2017-02-01

Ideal cardiovascular health has been defined by the American Heart Association as the absence of disease and the presence of seven key health factors and behaviours. However, little is known about the mental aspects associated with ideal cardiovascular health metrics. The objective of this study was to assess the relationships between psychosocial risk factors and ideal cardiovascular health metrics among Finnish women at municipal work units. A cross-sectional study was conducted in Finland among 732 female employees (mean±SD age 48±10 years) from ten work units in 2014. Ideal cardiovascular health metrics were evaluated with a physical examination, laboratory tests, medical history and self-administrated questionnaires. Psychosocial risk factors (social isolation, stress, depressive symptoms, anxiety, hostility and type D personality) were assessed with core questions as suggested by the European Society of Cardiology. The prevalence of having 5-7 ideal cardiovascular health metrics was 183 (25.0%), of whom 54.1% had at least one psychosocial risk factor. Anxiety (31.3%), work stress (30.7%) and type D personality (26.1%) were the most prevalent of the psychosocial risk factors. The prevalence of depressive symptoms ( p<0.001) and type D personality ( p=0.049) decreased linearly according to the sum of ideal cardiovascular health metrics after adjustment for age and years of education. Even women with good cardiovascular health are affected by psychosocial risk factors at municipal work units. Although the association is possibly bidirectional, screening and treating depression and dealing with type D personality might be crucial in improving cardiovascular health among women.

Patients respond more positively to physicians who focus on their ideal affect.

PubMed

Sims, Tamara; Tsai, Jeanne L

2015-06-01

Previous findings suggest that patients choose physicians whose affective focus matches how they ideally want to feel (Sims et al., 2014). For instance, the more people wanted to feel excitement, the more likely they were to hypothetically choose a new physician who promoted excitement. What remains unknown is whether this match shapes how patients actually respond to physicians after being assigned to them (i.e., whether they adhere to physicians' recommendations more and evaluate physicians more positively). To this end, community adults reported their global ideal affect and actual affect (how they ideally want to feel and actually feel during a typical week, respectively), and were randomly assigned to receive health recommendations from either a physician who expressed and promoted high arousal positive states (HAP) (e.g., excitement), or one who expressed and promoted low arousal positive states (LAP) (e.g., calm). For the next 5 days, participants reported their daily adherence to the recommendations and their daily ideal and actual affect. At the end of the week, participants evaluated their physician. As predicted, the more participants wanted to feel HAP, the more they adhered to the "HAP-focused" physician's recommendations, and the more participants wanted to feel LAP, the more they adhered to the "LAP-focused" physician's recommendations. Participants also evaluated their physician more positively when his affective focus matched their ideal affect. Neither global nor daily actual affect systematically predicted how patients responded to their physicians. These findings suggest that patients respond better to physicians whose affective focus matches their ideal affect. (c) 2015 APA, all rights reserved).

Patients Respond More Positively to Physicians Who Focus on Their Ideal Affect

PubMed Central

Sims, Tamara; Tsai, Jeanne L.

2014-01-01

Previous findings suggest that patients choose physicians whose affective focus matches how they ideally want to feel (Sims et al., 2014). For instance, the more people wanted to feel excitement, the more likely they were to hypothetically choose a new physician who promoted excitement. What remains unknown is whether this match shapes how patients actually respond to physicians after being assigned to them (i.e., whether they adhere to physicians’ recommendations more and evaluate physicians more positively). To this end, community adults reported their global ideal affect and actual affect (how they ideally want to feel and actually feel during a typical week, respectively), and were randomly assigned to receive health recommendations from either a physician who expressed and promoted high arousal positive states (HAP) (e.g., excitement), or one who expressed and promoted low arousal positive states (LAP) (e.g., calm). For the next five days, participants reported their daily adherence to the recommendations and their daily ideal and actual affect. At the end of the week, participants evaluated their physician. As predicted, the more participants wanted to feel HAP, the more they adhered to the “HAP-focused” physician’s recommendations, and the more participants wanted to feel LAP, the more they adhered to the “LAP-focused” physician’s recommendations. Participants also evaluated their physician more positively when his affective focus matched their ideal affect. Neither global nor daily actual affect systematically predicted how patients responded to their physicians. These findings suggest that patients respond better to physicians whose affective focus matches their ideal affect. PMID:25313670

Exact Solution of the Two-Dimensional Problem on an Impact Ideal-Liquid Jet

NASA Astrophysics Data System (ADS)

Belik, V. D.

2018-05-01

The two-dimensional problem on the collision of a potential ideal-liquid jet, outflowing from a reservoir through a nozzle, with an infinite plane obstacle was considered for the case where the distance between the nozzle exit section and the obstacle is finite. An exact solution of this problem has been found using methods of the complex-variable function theory. Simple analytical expressions for the complex velocity of the liquid, its flow rate, and the force of action of the jet on the obstacle have been obtained. The velocity distributions of the liquid at the nozzle exit section, in the region of spreading of the jet, and at the obstacle have been constructed for different distances between the nozzle exit section and the obstacle. Analytical expressions for the thickness of the boundary layer and the Nusselt number at the point of stagnation of the jet have been obtained. A number of distributions of the local friction coefficient and the Nusselt number of the indicated jet are presented.

Highlighting landslides and other geomorphological features using sediment connectivity maps

NASA Astrophysics Data System (ADS)

Bossi, Giulia; Crema, Stefano; Cavalli, Marco; Marcato, Gianluca; Pasuto, Alessandro

2016-04-01

Landslide identification is usually made through interpreting geomorphological features in the field or with remote sensing imagery. In recent years, airborne laser scanning (LiDAR) has enhanced the potentiality of geomorphological investigations by providing a detailed and diffuse representation of the land surface. The development of algorithms for geomorphological analysis based on LiDAR derived high-resolution Digital Terrain Models (DTMs) is increasing. Among them, the sediment connectivity index (IC) has been used to quantify sediment dynamics in alpine catchments. In this work, maps of the sediment connectivity index are used for detecting geomorphological features and processes not exclusively related to water-laden processes or debris flows. The test area is located in the upper Passer Valley in South Tyrol (Italy). Here a 4 km2 Deep-seated Gravitational Slope Deformation (DGSD) with several secondary phenomena has been studied for years. The connectivity index was applied to a well-known study area in order to evaluate its effectiveness as an interpretative layer to assist geomorphological analysis. Results were cross checked with evidence previously identified by means of in situ investigations, photointerpretation and monitoring data. IC was applied to a 2.5 m LiDAR derived DTM using two different scenarios in order to test their effectiveness: i) IC derived on the hydrologically correct DTM; ii) IC derived on the original DTM. In the resulting maps a cluster of low-connectivity areas appears as the deformation of the DGSD induce a convexity in the central part of the phenomenon. The double crests, product of the sagging of the landslide, are extremely evident since in those areas the flow directions diverge from the general drainage pattern, which is directed towards the valley river. In the crown area a rock-slab that shows clear evidence of incumbent detachment is clearly highlighted since the maps emphasize the presence of traction trenches and

Associations between Sexual Abstinence Ideals, Religiosity, and Alcohol Abstinence: A Longitudinal Study of Finnish Twins

PubMed Central

Winter, Torsten; Karvonen, Sakari; Rose, Richard J.

2016-01-01

We analyzed prevalence and stability of attitudes endorsing sexual abstinence ideals from late adolescence into early adulthood and studied associations of these attitudes with religiosity and alcohol abstinence in a sexually liberal Nordic society. Our population-based sample of Finnish twins permitted comparisons of co-twins concordant for religiosity but discordant for drinking to evaluate the association of sexual abstinence ideals with alcohol abstinence, controlling for household environment. From age 17 to 24, endorsement of sexual abstinence as a romantic ideal declined from 25% to 15%. Religiosity and alcohol abstinence correlated, both separately and together, with endorsing sexual abstinence. Abstinence ideals were associated with literal belief in fundamental tenets of the Bible. The association of sexual abstinence ideals with alcohol abstinence was confirmed in within-family comparisons of co-twins discordant for drinking but concordant for religiosity. Alcohol-abstinent twins were significantly more likely than their non-alcohol-abstinent twin siblings to endorse sexual abstinence ideals; that result suggests the association of sexual abstinence ideals with abstaining from alcohol is not explained by unmeasured confounds in familial background and structure. Our longitudinal results and analyses of discordant twins suggest that attitudes toward sexual abstinence ideals are embedded within other conservative attitudes and behaviors. PMID:23301620

The influence of family context on life, educational and occupational ideal among middle school students in China.

PubMed

Yao, Benxian; Zhang, Ling; Zhen, Rui; Zhou, Xiao

2016-06-01

This study examined the relationship between family context of middle school students on their educational and occupational ideals. Middle school students (N = 2000) responded to questions assessing family location, family structure, parental educational level and family economic status, as well as to the Middle School Students' Ideals Questionnaire. Multivariate analysis of variance indicated that life, educational and occupational ideals of female students and students in lower grades were higher than that of male students and students in higher grades. Regression analysis indicated that paternal education level have a positive association with educational and occupational ideals, but not life ideals, and family economic status have a positive relation to life ideals, but not educational and occupational ideals. Moreover, the interaction between family economic status and family location has a negative association with students' life, educational and occupational ideals. These results suggest that different factors predicted different ideals of adolescents, and that family economic status had a negative moderating effect on the relationship between family location and ideals of students. © 2015 International Union of Psychological Science.

Ideal gas thermodynamic properties for the phenyl, phenoxy, and o-biphenyl radicals

NASA Technical Reports Server (NTRS)

Burcat, A.; Zeleznik, F. J.; Mcbride, B. J.

1985-01-01

Ideal gas thermodynamic properties of the phenyl and o-biphenyl radicals, their deuterated analogs and the phenoxy radical were calculated to 5000 K using estimated vibrational frequencies and structures. The ideal gas thermodynamic properties of benzene, biphenyl, their deuterated analogs and phenyl were also calculated.

Blood flow and blood cell interactions and migration in microvessels

NASA Astrophysics Data System (ADS)

Fedosov, Dmitry; Fornleitner, Julia; Gompper, Gerhard

2011-11-01

Blood flow in microcirculation plays a fundamental role in a wide range of physiological processes and pathologies in the organism. To understand and, if necessary, manipulate the course of these processes it is essential to investigate blood flow under realistic conditions including deformability of blood cells, their interactions, and behavior in the complex microvascular network which is characteristic for the microcirculation. We employ the Dissipative Particle Dynamics method to model blood as a suspension of deformable cells represented by a viscoelastic spring-network which incorporates appropriate mechanical and rheological cell-membrane properties. Blood flow is investigated in idealized geometries. In particular, migration of blood cells and their distribution in blood flow are studied with respect to various conditions such as hematocrit, flow rate, red blood cell aggregation. Physical mechanisms which govern cell migration in microcirculation and, in particular, margination of white blood cells towards the vessel wall, will be discussed. In addition, we characterize blood flow dynamics and quantify hemodynamic resistance. D.F. acknowledges the Humboldt Foundation for financial support.

Biofilm effect on flow structure over a permeable bed

NASA Astrophysics Data System (ADS)

Kazemifar, Farzan; Blois, Gianluca; Aybar, Marcelo; Perez-Calleja, Patricia; Nerenberg, Robert; Sinha, Sumit; Hardy, Richard; Best, James; Sambrook Smith, Gregory; Christensen, Kenneth

2017-11-01

Biofilms constitute an important form of bacterial life in aquatic environments and are present at the fluid-solid interfaces in natural and industrial settings, such as water distribution systems and riverbeds among others. The permeable, heterogeneous, and deformable structure of biofilms can influence mass and momentum transport between the subsurface and freestream. However, this interaction is not fully understood, in part due to technical obstacles impeding quantitative experimental investigations. In this work, the effect of biofilm on flow structure over a permeable bed is studied. Experiments are conducted in a closed water channel equipped with an idealized two-dimensional permeable bed. Prior to conducting flow experiments, the models are placed within an independent recirculating reactor for biofilm growth. Once a targeted biofilm growth stage is achieved, the models are transferred to the water channel and subjected to transitional and turbulent flows. Long-distance microscopic particle image velocimetry measurements are performed to quantify the effect of biofilm on the turbulence structure of the free flow as well as the freestream-subsurface flow interaction. Funded by UK Natural Environment Research Council.

Biofilm Effect on Flow Structure over a Permeable Bed

NASA Astrophysics Data System (ADS)

Kazemifar, F.; Blois, G.; Aybar, M.; Perez-Calleja, P.; Nerenberg, R.; Sinha, S.; Hardy, R. J.; Best, J.; Sambrook Smith, G.; Christensen, K. T.

2017-12-01

Biofilms constitute an important form of bacterial life in aquatic environments and are present at the fluid-solid interfaces in natural and industrial settings, such as water distribution systems and riverbeds among others. The permeable, heterogeneous, and deformable structure of biofilms can influence mass and momentum transport between the subsurface and freestream. However, this interaction is not fully understood, in part due to technical obstacles impeding quantitative experimental investigations. In this work, the effect of biofilm on flow structure over a permeable bed is studied. Experiments are conducted in a closed water channel equipped with an idealized two-dimensional permeable bed. Prior to conducting flow experiments, the models are placed within an independent recirculating reactor for biofilm growth. Once a targeted biofilm growth stage is achieved, the models are transferred to the water channel and subjected to transitional and turbulent flows. Long-distance microscopic particle image velocimetry measurements are performed to quantify the effect of biofilm on the turbulence structure of the free flow as well as the freestream-subsurface flow interaction.

Conservation laws and evolution schemes in geodesic, hydrodynamic, and magnetohydrodynamic flows

NASA Astrophysics Data System (ADS)

Markakis, Charalampos; Uryū, Kōji; Gourgoulhon, Eric; Nicolas, Jean-Philippe; Andersson, Nils; Pouri, Athina; Witzany, Vojtěch

2017-09-01

Carter and Lichnerowicz have established that barotropic fluid flows are conformally geodesic and obey Hamilton's principle. This variational approach can accommodate neutral, or charged and poorly conducting, fluids. We show that, unlike what has been previously thought, this approach can also accommodate perfectly conducting magnetofluids, via the Bekenstein-Oron description of ideal magnetohydrodynamics. When Noether symmetries associated with Killing vectors or tensors are present in geodesic flows, they lead to constants of motion polynomial in the momenta. We generalize these concepts to hydrodynamic flows. Moreover, the Hamiltonian descriptions of ideal magnetohydrodynamics allow one to cast the evolution equations into a hyperbolic form useful for evolving rotating or binary compact objects with magnetic fields in numerical general relativity. In this framework, Ertel's potential vorticity theorem for baroclinic fluids arises as a special case of a conservation law valid for any Hamiltonian system. Moreover, conserved circulation laws, such as those of Kelvin, Alfvén and Bekenstein-Oron, emerge simply as special cases of the Poincaré-Cartan integral invariant of Hamiltonian systems. We use this approach to obtain an extension of Kelvin's theorem to baroclinic (nonisentropic) fluids, based on a temperature-dependent time parameter. We further extend this result to perfectly or poorly conducting baroclinic magnetoflows. Finally, in the barotropic case, such magnetoflows are shown to also be geodesic, albeit in a Finsler (rather than Riemann) space.

Holographic aids for internal combustion engine flow studies

NASA Technical Reports Server (NTRS)

Regan, C.

1984-01-01

Worldwide interest in improving the fuel efficiency of internal combustion (I.C.) engines has sparked research efforts designed to learn more about the flow processes of these engines. The flow fields must be understood prior to fuel injection in order to design efficient valves, piston geometries, and fuel injectors. Knowledge of the flow field is also necessary to determine the heat transfer to combustion chamber surfaces. Computational codes can predict velocity and turbulence patterns, but experimental verification is mandatory to justify their basic assumptions. Due to their nonintrusive nature, optical methods are ideally suited to provide the necessary velocity verification data. Optical sytems such as Schlieren photography, laser velocimetry, and illuminated particle visualization are used in I.C. engines, and now their versatility is improved by employing holography. These holographically enhanced optical techniques are described with emphasis on their applications in I.C. engines.

Beyond ideal magnetohydrodynamics: from fibration to 3  +  1 foliation

NASA Astrophysics Data System (ADS)

Andersson, N.; Hawke, I.; Dionysopoulou, K.; Comer, G. L.

2017-06-01

We consider a resistive multi-fluid framework from the 3  +  1 space-time foliation point-of-view, paying particular attention to issues relating to the use of multi-parameter equations of state and the associated inversion from evolved to primitive variables. We highlight relevant numerical issues that arise for general systems with relative flows. As an application of the new formulation, we consider a three-component system relevant for hot neutron stars. In this case we let the baryons (neutrons and protons) move together, but allow heat and electrons to exhibit relative flow. This reduces the problem to three momentum equations; overall energy-momentum conservation, a generalised Ohm’s law and a heat equation. Our results provide a hierarchy of increasingly complex models and prepare the ground for new state-of-the-art simulations of relevant scenarios in relativistic astrophysics.

Anisotropic hydrodynamics for conformal Gubser flow

NASA Astrophysics Data System (ADS)

Nopoush, Mohammad; Ryblewski, Radoslaw; Strickland, Michael

2015-02-01

We derive the equations of motion for a system undergoing boost-invariant longitudinal and azimuthally symmetric transverse "Gubser flow" using leading-order anisotropic hydrodynamics. This is accomplished by assuming that the one-particle distribution function is ellipsoidally symmetric in the momenta conjugate to the de Sitter coordinates used to parametrize the Gubser flow. We then demonstrate that the S O (3 )q symmetry in de Sitter space further constrains the anisotropy tensor to be of spheroidal form. The resulting system of two coupled ordinary differential equations for the de Sitter-space momentum scale and anisotropy parameter are solved numerically and compared to a recently obtained exact solution of the relaxation-time-approximation Boltzmann equation subject to the same flow. We show that anisotropic hydrodynamics describes the spatiotemporal evolution of the system better than all currently known dissipative hydrodynamics approaches. In addition, we prove that anisotropic hydrodynamics gives the exact solution of the relaxation-time approximation Boltzmann equation in the ideal, η /s →0 , and free-streaming, η /s →∞, limits.

Homogeneous purely buoyancy driven turbulent flow

NASA Astrophysics Data System (ADS)

Arakeri, Jaywant; Cholemari, Murali; Pawar, Shashikant

2010-11-01

An unstable density difference across a long vertical tube open at both ends leads to convection that is axially homogeneous with a linear density gradient. We report results from such tube convection experiments, with driving density caused by salt concentration difference or temperature difference. At high enough Rayleigh numbers (Ra) the convection is turbulent with zero mean flow and zero mean Reynolds shear stresses; thus turbulent production is purely by buoyancy. We observe different regimes of turbulent convection. At very high Ra the Nusselt number scales as the square root of the Rayleigh number, giving the so-called "ultimate regime" of convection predicted for Rayleigh-Benard convection in limit of infinite Ra. Turbulent convection at intermediate Ra, the Nusselt number scales as Ra^0.3. In both regimes, the flux and the Taylor scale Reynolds number are more than order of magnitude larger than those obtained in Rayleigh-Benard convection. Absence of a mean flow makes this an ideal flow to study shear free turbulence near a wall.

Lifestyle constraints, not inadequate nutrition education, cause gap between breakfast ideals and realities among Japanese in Tokyo.

PubMed

Melby, Melissa K; Takeda, Wakako

2014-01-01

Japanese public health nutrition often promotes 'traditional' cuisine. In-depth interviews with 107 Japanese adults were conducted in Tokyo from 2009 to 2011, using free-listing methods to examine dietary ideals and realities to assess the extent to which realities reflect inadequate nutrition education or lifestyle constraints. Ideal-reality gaps were widest for breakfast. Most people reported Japanese ideals: rice and miso soup were prototypical foods. However, breakfast realities were predominantly western (bread-based). While those aged 40-59 were more likely to hold Japanese ideals (P=0.063), they were less likely to achieve them (P=0.007). All those reporting western ideals achieved them on weekdays, while only 64% of those with Japanese ideals achieved them (P<0.001). Partial correlations controlling for age and gender showed achievement of Japanese ideals were positively correlated with proportion of cooking-related housework, and negatively correlated with living standard and income. Ideal menu content was in line with current Japanese nutrition advice, suggesting that more nutrition education may not change dietary ideals or behavior. Participant-reported reasons for ideal-reality discordance demonstrate that work-life balance issues, especially lack of time and family structure/life rhythm, are the largest obstacles to the attainment of dietary ideals. People reporting 'no time' as a primary reason for ideal-reality gaps were less likely to achieve their Japanese ideals (odds ratio=0.212). Time realities of people's lives may undermine educational efforts promoting Japanese breakfasts. When dietary reality/behavior departs from guidelines, it is often assumed that people lack knowledge. If ideals are in line with dietary guidelines, then lack of knowledge is not the likely cause and nutrition education is not the optimal solution. By asking people about the reasons for gaps between their ideals and realities, we can identify barriers and design more

Numerical simulation of transient hypervelocity flow in an expansion tube

NASA Technical Reports Server (NTRS)

Jacobs, P. A.

1992-01-01

Several numerical simulations of the transient flow of helium in an expansion tube are presented. The aim of the exercise is to provide further information on the operational problems of the NASA Langley expansion tube. The calculations were performed with an axisymmetric Navier-Stokes code based on a finite-volume formulation and upwinding techniques. Although laminar flow and ideal bursting of the diaphragms was assumed, the simulations showed some of the important features seen in the experiments. In particular, the discontinuity in the tube diameter at the primary diaphragm station introduced a transverse perturbation to the expanding driver gas, and this perturbation was seen to propagate into the test gas under some flow conditions. The disturbances seen in the test flow can be characterized as either 'small-amplitude' noise possibly introduced during shock compression or 'large-amplitude' noise associated with the passage of the reflected head of the unsteady expansion.

How Is the Ideal Gas Law Explanatory?

ERIC Educational Resources Information Center

Woody, Andrea I.

2013-01-01

Using the ideal gas law as a comparative example, this essay reviews contemporary research in philosophy of science concerning scientific explanation. It outlines the inferential, causal, unification, and erotetic conceptions of explanation and discusses an alternative project, the functional perspective. In each case, the aim is to highlight…

Ideal versus School Learning: Analyzing Israeli Secondary School Students' Conceptions of Learning

ERIC Educational Resources Information Center

Hadar, Linor

2009-01-01

This study explored 130 secondary school students' conceptions of learning using an open-ended task, analyzed both qualitatively and quantitatively. Students' reality of learning comprised two separate spheres, ideal learning and school learning, which rarely interacted. Generally, students commented more about school than ideal learning. Factor…

A complete equation of state for non-ideal condensed phase explosives

NASA Astrophysics Data System (ADS)

Wilkinson, S. D.; Braithwaite, M.; Nikiforakis, N.; Michael, L.

2017-12-01

The objective of this work is to improve the robustness and accuracy of numerical simulations of both ideal and non-ideal explosives by introducing temperature dependence in mechanical equations of state for reactants and products. To this end, we modify existing mechanical equations of state to appropriately approximate the temperature in the reaction zone. Mechanical equations of state of the Mie-Grüneisen form are developed with extensions, which allow the temperature to be evaluated appropriately and the temperature equilibrium condition to be applied robustly. Furthermore, the snow plow model is used to capture the effect of porosity on the reactant equation of state. We apply the methodology to predict the velocity of compliantly confined detonation waves. Once reaction rates are calibrated for unconfined detonation velocities, simulations of confined rate sticks and slabs are performed, and the experimental detonation velocities are matched without further parameter alteration, demonstrating the predictive capability of our simulations. We apply the same methodology to both ideal (PBX9502, a high explosive with principal ingredient TATB) and non-ideal (EM120D, an ANE or ammonium nitrate based emulsion) explosives.

Flow Diverters for Intracranial Aneurysms

PubMed Central

Alderazi, Yazan J.; Kass-Hout, Tareq; Prestigiacomo, Charles J.; Gandhi, Chirag D.

2014-01-01

Flow diverters (pipeline embolization device, Silk flow diverter, and Surpass flow diverter) have been developed to treat intracranial aneurysms. These endovascular devices are placed within the parent artery rather than the aneurysm sac. They take advantage of altering hemodynamics at the aneurysm/parent vessel interface, resulting in gradual thrombosis of the aneurysm occurring over time. Subsequent inflammatory response, healing, and endothelial growth shrink the aneurysm and reconstruct the parent artery lumen while preserving perforators and side branches in most cases. Flow diverters have already allowed treatment of previously untreatable wide neck and giant aneurysms. There are risks with flow diverters including in-stent thrombosis, perianeurysmal edema, distant and delayed hemorrhages, and perforator occlusions. Comparative efficacy and safety against other therapies are being studied in ongoing trials. Antiplatelet therapy is mandatory with flow diverters, which has highlighted the need for better evidence for monitoring and tailoring antiplatelet therapy. In this paper we review the devices, their uses, associated complications, evidence base, and ongoing studies. PMID:24967131

Experimental quantification of the fluid dynamics in blood-processing devices through 4D-flow imaging: A pilot study on a real oxygenator/heat-exchanger module.

PubMed

Piatti, Filippo; Palumbo, Maria Chiara; Consolo, Filippo; Pluchinotta, Francesca; Greiser, Andreas; Sturla, Francesco; Votta, Emiliano; Siryk, Sergii V; Vismara, Riccardo; Fiore, Gianfranco Beniamino; Lombardi, Massimo; Redaelli, Alberto

2018-02-08

The performance of blood-processing devices largely depends on the associated fluid dynamics, which hence represents a key aspect in their design and optimization. To this aim, two approaches are currently adopted: computational fluid-dynamics, which yields highly resolved three-dimensional data but relies on simplifying assumptions, and in vitro experiments, which typically involve the direct video-acquisition of the flow field and provide 2D data only. We propose a novel method that exploits space- and time-resolved magnetic resonance imaging (4D-flow) to quantify the complex 3D flow field in blood-processing devices and to overcome these limitations. We tested our method on a real device that integrates an oxygenator and a heat exchanger. A dedicated mock loop was implemented, and novel 4D-flow sequences with sub-millimetric spatial resolution and region-dependent velocity encodings were defined. Automated in house software was developed to quantify the complex 3D flow field within the different regions of the device: region-dependent flow rates, pressure drops, paths of the working fluid and wall shear stresses were computed. Our analysis highlighted the effects of fine geometrical features of the device on the local fluid-dynamics, which would be unlikely observed by current in vitro approaches. Also, the effects of non-idealities on the flow field distribution were captured, thanks to the absence of the simplifying assumptions that typically characterize numerical models. To the best of our knowledge, our approach is the first of its kind and could be extended to the analysis of a broad range of clinically relevant devices. Copyright © 2017 Elsevier Ltd. All rights reserved.

Learning what feelings to desire: socialization of ideal affect through children's storybooks.

PubMed

Tsai, Jeanne L; Louie, Jennifer Y; Chen, Eva E; Uchida, Yukiko

2007-01-01

Previous findings suggest that cultural factors influence ideal affect (i.e., the affective states that people ideally want to feel). Three studies tested the hypothesis that cultural differences in ideal affect emerge early in life and are acquired through exposure to storybooks. In Study 1, the authors established that consistent with previous findings, European American preschoolers preferred excited (vs. calm) states more (indexed by activity and smile preferences) and perceived excited (vs. calm) states as happier than Taiwanese Chinese preschoolers. In Study 2, it was observed that similar differences were reflected in the pictures (activities, expressions, and smiles) of best-selling storybooks in the United States and Taiwan. Study 3 found that across cultures, exposure to exciting (vs. calm) storybooks altered children's preferences for excited (vs. calm) activities and their perceptions of happiness. These findings suggest that cultural differences in ideal affect may be due partly to differential exposure to calm and exciting storybooks.

Symplectic homoclinic tangles of the ideal separatrix of the DIII-D from type I ELMs

NASA Astrophysics Data System (ADS)

Punjabi, Alkesh; Ali, Halima

2012-10-01

The ideal separatrix of the divertor tokamaks is a degenerate manifold where both the stable and unstable manifolds coincide. Non-axisymmetric magnetic perturbations remove the degeneracy; and split the separatrix manifold. This creates an extremely complex topological structure, called homoclinic tangles. The unstable manifold intersects the stable manifold and creates alternating inner and outer lobes at successive homoclinic points. The Hamiltonian system must preserve the symplectic topological invariance, and this controls the size and radial extent of the lobes. Very recently, lobes near the X-point have been experimentally observed in MAST [A. Kirk et al, PRL 108, 255003 (2012)]. We have used the DIII-D map [A. Punjabi, NF 49, 115020 (2009)] to calculate symplectic homoclinic tangles of the ideal separatrix of the DIII-D from the type I ELMs represented by the peeling-ballooning modes (m,n)=(30,10)+(40,10). The DIII-D map is symplectic, accurate, and is in natural canonical coordinates which are invertible to physical coordinates [A. Punjabi and H. Ali, POP 15, 122502 (2008)]. To our knowledge, we are the first to symplectically calculate these tangles in physical space. Homoclinic tangles of separatrix can cause radial displacement of mobile passing electrons and create sheared radial electric fields and currents, resulting in radial flows, drifts, differential spinning, and reduction in turbulence, and other effects. This work is supported by the grants DE-FG02-01ER54624 and DE-FG02-04ER54793.

Molecular determinants of cadherin ideal bond formation: Conformation-dependent unbinding on a multidimensional landscape

PubMed Central

Manibog, Kristine; Sankar, Kannan; Kim, Sun-Ae; Zhang, Yunxiang; Jernigan, Robert L.; Sivasankar, Sanjeevi

2016-01-01

Classical cadherin cell–cell adhesion proteins are essential for the formation and maintenance of tissue structures; their primary function is to physically couple neighboring cells and withstand mechanical force. Cadherins from opposing cells bind in two distinct trans conformations: strand-swap dimers and X-dimers. As cadherins convert between these conformations, they form ideal bonds (i.e., adhesive interactions that are insensitive to force). However, the biophysical mechanism for ideal bond formation is unknown. Here, we integrate single-molecule force measurements with coarse-grained and atomistic simulations to resolve the mechanistic basis for cadherin ideal bond formation. Using simulations, we predict the energy landscape for cadherin adhesion, the transition pathways for interconversion between X-dimers and strand-swap dimers, and the cadherin structures that form ideal bonds. Based on these predictions, we engineer cadherin mutants that promote or inhibit ideal bond formation and measure their force-dependent kinetics using single-molecule force-clamp measurements with an atomic force microscope. Our data establish that cadherins adopt an intermediate conformation as they shuttle between X-dimers and strand-swap dimers; pulling on this conformation induces a torsional motion perpendicular to the pulling direction that unbinds the proteins and forms force-independent ideal bonds. Torsional motion is blocked when cadherins associate laterally in a cis orientation, suggesting that ideal bonds may play a role in mechanically regulating cadherin clustering on cell surfaces. PMID:27621473

Diverting lava flows in the lab

USGS Publications Warehouse

Dietterich, Hannah; Cashman, Katharine V.; Rust, Alison C.; Lev, Einat

2015-01-01

Recent volcanic eruptions in Hawai'i, Iceland and Cape Verde highlight the challenges of mitigating hazards when lava flows threaten infrastructure. Diversion barriers are the most common form of intervention, but historical attempts to divert lava flows have met with mixed success and there has been little systematic analysis of optimal barrier design. We examine the interaction of viscous flows of syrup and molten basalt with barriers in the laboratory. We find that flows thicken immediately upslope of an obstacle, forming a localized bow wave that can overtop barriers. Larger bow waves are generated by faster flows and by obstacles oriented at a high angle to the flow direction. The geometry of barriers also influences flow behaviour. Barriers designed to split or dam flows will slow flow advance, but cause the flow to widen, whereas oblique barriers can effectively divert flows, but may also accelerate flow advance. We argue that to be successful, mitigation of lava-flow hazards must incorporate the dynamics of lava flow–obstacle interactions into barrier design. The same generalizations apply to the effect of natural topographic features on flow geometry and advance rates.

Transcriptomic changes in the pre-implantation uterus highlight histotrophic nutrition of the developing marsupial embryo.

PubMed

Whittington, Camilla M; O'Meally, Denis; Laird, Melanie K; Belov, Katherine; Thompson, Michael B; McAllan, Bronwyn M

2018-02-05

Early pregnancy is a critical time for successful reproduction; up to half of human pregnancies fail before the development of the definitive chorioallantoic placenta. Unlike the situation in eutherian mammals, marsupial pregnancy is characterised by a long pre-implantation period prior to the development of the short-lived placenta, making them ideal models for study of the uterine environment promoting embryonic survival pre-implantation. Here we present a transcriptomic study of pre-implantation marsupial pregnancy, and identify differentially expressed genes in the Sminthopsis crassicaudata uterus involved in metabolism and biosynthesis, transport, immunity, tissue remodelling, and uterine receptivity. Interestingly, almost one quarter of the top 50 genes that are differentially upregulated in early pregnancy are putatively involved in histotrophy, highlighting the importance of nutrient transport to the conceptus prior to the development of the placenta. This work furthers our understanding of the mechanisms underlying survival of pre-implantation embryos in the earliest live bearing ancestors of mammals.

Dimensional analysis using toric ideals: primitive invariants.

PubMed

Atherton, Mark A; Bates, Ronald A; Wynn, Henry P

2014-01-01

Classical dimensional analysis in its original form starts by expressing the units for derived quantities, such as force, in terms of power products of basic units [Formula: see text] etc. This suggests the use of toric ideal theory from algebraic geometry. Within this the Graver basis provides a unique primitive basis in a well-defined sense, which typically has more terms than the standard Buckingham approach. Some textbook examples are revisited and the full set of primitive invariants found. First, a worked example based on convection is introduced to recall the Buckingham method, but using computer algebra to obtain an integer [Formula: see text] matrix from the initial integer [Formula: see text] matrix holding the exponents for the derived quantities. The [Formula: see text] matrix defines the dimensionless variables. But, rather than this integer linear algebra approach it is shown how, by staying with the power product representation, the full set of invariants (dimensionless groups) is obtained directly from the toric ideal defined by [Formula: see text]. One candidate for the set of invariants is a simple basis of the toric ideal. This, although larger than the rank of [Formula: see text], is typically not unique. However, the alternative Graver basis is unique and defines a maximal set of invariants, which are primitive in a simple sense. In addition to the running example four examples are taken from: a windmill, convection, electrodynamics and the hydrogen atom. The method reveals some named invariants. A selection of computer algebra packages is used to show the considerable ease with which both a simple basis and a Graver basis can be found.

Time-dependent solution for axisymmetric flow over a blunt body with ideal gas, CF4, or equilibrium air chemistry

NASA Technical Reports Server (NTRS)

Hamilton, H. H., II; Spall, J. R.

1986-01-01

A time-asymptotic method has been used to obtain steady-flow solutions for axisymmetric inviscid flow over several blunt bodies including spheres, paraboloids, ellipsoids, and spherically blunted cones. Comparisons with experimental data and results of other computational methods have demonstrated that accurate solutions can be obtained using this approach. The method should prove useful as an analysis tool for comparing with experimental data and for making engineering calculations for blunt reentry vehicles.

Time-dependent solution for axisymmetric flow over a blunt body with ideal gas, CF4, or equilibrium air chemistry

NASA Astrophysics Data System (ADS)

Hamilton, H. H., II; Spall, J. R.

1986-07-01

A time-asymptotic method has been used to obtain steady-flow solutions for axisymmetric inviscid flow over several blunt bodies including spheres, paraboloids, ellipsoids, and spherically blunted cones. Comparisons with experimental data and results of other computational methods have demonstrated that accurate solutions can be obtained using this approach. The method should prove useful as an analysis tool for comparing with experimental data and for making engineering calculations for blunt reentry vehicles.

Ideal Directed-Energy System To Defeat Small Unmanned Aircraft System Swarms

DTIC Science & Technology

2017-05-21

AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY IDEAL DIRECTED- ENERGY SYSTEM TO DEFEAT SMALL UNMANNED AIRCRAFT SYSTEM SWARMS by David F. Pina...directed energy (DE) developmental systems indicate this class of weapons is the best solution. A review of several continuous wave laser, pulsed high...powered microwave, and electronic warfare/jamming systems indicate the following attributes as ideal for a future directed energy weapon (DEW) system

Real vs. Ideal Self Discrepancy in Bulimics.

ERIC Educational Resources Information Center

Kosak, Karen

Bulimia is an eating disorder prevalent among young women, characterized by binge eating episodes followed by purging with subsequent depressive moods and self-deprecating thoughts. To determine whether bulimic women exhibit a greater discrepancy between their perceived and ideal selves than do nonbulimics, three samples of women were assessed.…

Point-vortex stability under the influence of an external periodic flow

NASA Astrophysics Data System (ADS)

Ortega, Rafael; Ortega, Víctor; Torres, Pedro J.

2018-05-01

We provide sufficient conditions for the stability of the particle advection around a fixed vortex in a two-dimensional ideal fluid under the action of a periodic background flow. The proof relies on the identification of closed invariant curves around the origin by means of Moser’s invariant curve theorem. Partially supported by Spanish MINECO and ERDF project MTM2014-52232-P.

Development of comprehensive numerical schemes for predicting evaporating gas-droplets flow processes of a liquid-fueled combustor

NASA Technical Reports Server (NTRS)

Chen, C. P.

1990-01-01

An existing Computational Fluid Dynamics code for simulating complex turbulent flows inside a liquid rocket combustion chamber was validated and further developed. The Advanced Rocket Injector/Combustor Code (ARICC) is simplified and validated against benchmark flow situations for laminar and turbulent flows. The numerical method used in ARICC Code is re-examined for incompressible flow calculations. For turbulent flows, both the subgrid and the two equation k-epsilon turbulence models are studied. Cases tested include idealized Burger's equation in complex geometries and boundaries, a laminar pipe flow, a high Reynolds number turbulent flow, and a confined coaxial jet with recirculations. The accuracy of the algorithm is examined by comparing the numerical results with the analytical solutions as well as experimented data with different grid sizes.

Perturbative thermodynamic geometry of nonextensive ideal classical, Bose, and Fermi gases.

PubMed

Mohammadzadeh, Hosein; Adli, Fereshteh; Nouri, Sahereh

2016-12-01

We investigate perturbative thermodynamic geometry of nonextensive ideal classical, Bose, and Fermi gases. We show that the intrinsic statistical interaction of nonextensive Bose (Fermi) gas is attractive (repulsive) similar to the extensive case but the value of thermodynamic curvature is changed by a nonextensive parameter. In contrary to the extensive ideal classical gas, the nonextensive one may be divided to two different regimes. According to the deviation parameter of the system to the nonextensive case, one can find a special value of fugacity, z^{*}, where the sign of thermodynamic curvature is changed. Therefore, we argue that the nonextensive parameter induces an attractive (repulsive) statistical interaction for zz^{*}) for an ideal classical gas. Also, according to the singular point of thermodynamic curvature, we consider the condensation of nonextensive Boson gas.

Preserving idealism in global health promotion.

PubMed

Franco-Paredes, Carlos; Zeuli, Julia; Hernández-Ramos, Isabel; Santos-Preciado, Jose I

2010-12-01

If the field of global health is to evolve in the second decade of the new millennium, we need to revive the idealistic spirit and by using the lens of health equity work toward improved health status around the world. Morality and empathy are considered by-products of our evolutionary history as a human species. Idealism may be a trait that we may choose to preserve in our modern evolutionary history.

Note on the ideal frame formulation

NASA Astrophysics Data System (ADS)

Lara, Martin

2017-09-01

An implementation of the ideal frame formulation of perturbed Keplerian motion is presented which only requires the integration of a differential system of dimension 7, contrary to the 8 variables traditionally integrated with this approach. The new formulation is based on the integration of a scaled version of the Eulerian set of redundant parameters and slightly improves runtime performance with respect to the 8-dimensional case while retaining comparable accuracy.

A thickness-weighted average perspective of force balance in an idealized circumpolar current

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ringler, Todd Darwin; Saenz, Juan Antonio; Wolfram, Jr., Phillip Justin

The exact, three-dimensional thickness-weighted averaged (TWA) Boussinesq equations are used to diagnose eddy-mean flow interaction in an idealized circumpolar current (ICC). The force exerted by mesoscale eddies on the TWA velocity is expressed as the divergence of the Eliassen-Palm flux tensor. Consistent with previous findings, the analysis indicates that the dynamically relevant definition of the ocean surface layer is comprised of the set of buoyancy coordinates that ever reside at the ocean surface at a given horizontal position. The surface layer is found to be a physically distinct object with a diabatic- and force-balance that is largely isolated from themore » underlying adiabatic region in the interior. Within the ICC surface layer, the TWA meridional velocity is southward/northward in the top/bottom half, and has a value near zero at the bottom. In the top half of the surface layer, the zonal forces due to wind stress and meridional advection of potential vorticity act to accelerate the TWA zonal velocity; equilibrium is obtained by eddies decelerating the zonal flow via a downward flux of eastward momentum that increases with depth. In the bottom half of the surface layer, the accelerating force of the wind stress is balanced by the eddy force and meridional advection of potential vorticity. The bottom of the surface layer coincides with the location where the zonal eddy force, meridional advection of potential vorticity and zonal wind stress force are all zero. The net meridional transport, S f, within the surface layer is a small residual of its southward and northward TWA meridional flows. Furthermore, the mean meridional gradient of surface-layer buoyancy is advected by S f to balance the surface buoyancy fluxs.« less

A thickness-weighted average perspective of force balance in an idealized circumpolar current

DOE PAGES

Ringler, Todd Darwin; Saenz, Juan Antonio; Wolfram, Jr., Phillip Justin; ...

2016-11-22

The exact, three-dimensional thickness-weighted averaged (TWA) Boussinesq equations are used to diagnose eddy-mean flow interaction in an idealized circumpolar current (ICC). The force exerted by mesoscale eddies on the TWA velocity is expressed as the divergence of the Eliassen-Palm flux tensor. Consistent with previous findings, the analysis indicates that the dynamically relevant definition of the ocean surface layer is comprised of the set of buoyancy coordinates that ever reside at the ocean surface at a given horizontal position. The surface layer is found to be a physically distinct object with a diabatic- and force-balance that is largely isolated from themore » underlying adiabatic region in the interior. Within the ICC surface layer, the TWA meridional velocity is southward/northward in the top/bottom half, and has a value near zero at the bottom. In the top half of the surface layer, the zonal forces due to wind stress and meridional advection of potential vorticity act to accelerate the TWA zonal velocity; equilibrium is obtained by eddies decelerating the zonal flow via a downward flux of eastward momentum that increases with depth. In the bottom half of the surface layer, the accelerating force of the wind stress is balanced by the eddy force and meridional advection of potential vorticity. The bottom of the surface layer coincides with the location where the zonal eddy force, meridional advection of potential vorticity and zonal wind stress force are all zero. The net meridional transport, S f, within the surface layer is a small residual of its southward and northward TWA meridional flows. Furthermore, the mean meridional gradient of surface-layer buoyancy is advected by S f to balance the surface buoyancy fluxs.« less

Effect of pairwise additivity on finite-temperature behavior of classical ideal gas

NASA Astrophysics Data System (ADS)

Shekaari, Ashkan; Jafari, Mahmoud

2018-05-01

Finite-temperature molecular dynamics simulations have been applied to inquire into the effect of pairwise additivity on the behavior of classical ideal gas within the temperature range of T = 250-4000 K via applying a variety of pair potentials and then examining the temperature dependence of a number of thermodynamical properties. Examining the compressibility factor reveals the most deviation from ideal-gas behavior for the Lennard-Jones system mainly due to the presence of both the attractive and repulsive terms. The systems with either attractive or repulsive intermolecular potentials are found to present no resemblance to real gases, but the most similarity to the ideal one as temperature rises.

Some aspects of the problem of secondary eyewall formation in idealized three-dimensional nonlinear simulations

NASA Astrophysics Data System (ADS)

Menelaou, K.; Yau, M. K.; Martinez, Y.

2014-09-01

Some aspects of the problem of secondary eyewall formation (SEF) are investigated with the aid of an idealized model. A series of experiments are conducted, starting with a strong annular vortex embedded in a quiescent background flow and forced by the sustained heating associated with a spiral rainband (control experiment). Following this, two experiments are configured to assess the impact of vertical wind shear (VWS) in the SEF process. The importance of the boundary layer force imbalance is finally investigated in a number of simulations in which surface and boundary layer physics are included. From the control experiment, it is found that in the absence of background environmental flow, the sustained latent heating associated with a spiral rainband can form a secondary eyewall even in the absence of a frictional boundary layer. The presence of VWS acts negatively in the SEF process by disrupting the organization of the potential vorticity induced by the rainband. When boundary layer physics is included, some similarities with previous studies are seen, but there is no SEF. These results suggest that the boundary layer most likely contributes to, rather than initiate, a secondary eyewall. This article was corrected on 10 OCT 2014. See the end of the full text for details.

NASA Langley Highlights, 1998

NASA Technical Reports Server (NTRS)

1999-01-01

Langley's mission is accomplished by performing innovative research relevant to national needs and Agency goals, transferring technology to users in a timely manner, and providing development support to other United States Government Agencies, industry, other NASA Centers, the educational community, and the local community. This report contains highlights of some of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year. The highlights illustrate the broad range of research and technology activities carried out by NASA Langley Research Center and the contributions of this work toward maintaining United States' leadership in aeronautics and space research. A color electronic version of this report is available at URL http://larcpubs.larc.nasa.gov/randt/1998/.

Research and technology highlights, 1993

NASA Technical Reports Server (NTRS)

1994-01-01

This report contains highlights of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year. The highlights illustrate both the broad range of the research and technology activities supported by NASA Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research. This report also describes some of the Center's most important research and testing facilities.

Traffic Flow Management Wrap-Up

NASA Technical Reports Server (NTRS)

Grabbe, Shon

2011-01-01

Traffic Flow Management involves the scheduling and routing of air traffic subject to airport and airspace capacity constraints, and the efficient use of available airspace. Significant challenges in this area include: (1) weather integration and forecasting, (2) accounting for user preferences in the Traffic Flow Management decision making process, and (3) understanding and mitigating the environmental impacts of air traffic on the environment. To address these challenges, researchers in the Traffic Flow Management area are developing modeling, simulation and optimization techniques to route and schedule air traffic flights and flows while accommodating user preferences, accounting for system uncertainties and considering the environmental impacts of aviation. This presentation will highlight some of the major challenges facing researchers in this domain, while also showcasing recent innovations designed to address these challenges.

Ideal plasma response to vacuum magnetic fields with resonant magnetic perturbations in non-axisymmetric tokamaks

DOE PAGES

Kim, Kimin; Ahn, J. -W.; Scotti, F.; ...

2015-09-03

Ideal plasma shielding and amplification of resonant magnetic perturbations in non-axisymmetric tokamak is presented by field line tracing simulation with full ideal plasma response, compared to measurements of divertor lobe structures. Magnetic field line tracing simulations in NSTX with toroidal non-axisymmetry indicate the ideal plasma response can significantly shield/amplify and phase shift the vacuum resonant magnetic perturbations. Ideal plasma shielding for n = 3 mode is found to prevent magnetic islands from opening as consistently shown in the field line connection length profile and magnetic footprints on the divertor target. It is also found that the ideal plasma shielding modifiesmore » the degree of stochasticity but does not change the overall helical lobe structures of the vacuum field for n = 3. Furthermore, amplification of vacuum fields by the ideal plasma response is predicted for low toroidal mode n = 1, better reproducing measurements of strong striation of the field lines on the divertor plate in NSTX.« less

Continuous flow nitration in miniaturized devices

PubMed Central

2014-01-01

Summary This review highlights the state of the art in the field of continuous flow nitration with miniaturized devices. Although nitration has been one of the oldest and most important unit reactions, the advent of miniaturized devices has paved the way for new opportunities to reconsider the conventional approach for exothermic and selectivity sensitive nitration reactions. Four different approaches to flow nitration with microreactors are presented herein and discussed in view of their advantages, limitations and applicability of the information towards scale-up. Selected recent patents that disclose scale-up methodologies for continuous flow nitration are also briefly reviewed. PMID:24605161

Difference between highlight and object colors enhances glossiness.

PubMed

Hanada, Mitsuhiko

2012-06-01

The effect of highlight and object colors on perception of glossiness was examined. Ten participants rated glossiness of object images. The color coordinates of objects and highlights were varied while luminance of each pixel was unchanged. Four colors were used for objects and highlights. Objects were perceived as glossier when the highlight color was different from the object color than when they were the same. Objects with some unnatural combinations of highlight and object colors were perceived to be as glossy as those with natural color combinations. The results suggested that differences between highlight and object colors enhance perceived glossiness and that perceived glossiness does not depend on naturalness of color combination for highlights and objects.

Effects of flows on viscous and resistive MHD stability

NASA Technical Reports Server (NTRS)

Einaudi, Giorgio

1986-01-01

In many solar applications the viscosity appears to be more important than resistivity. In order to discuss the instabilities in solar conditions, an idealized configuration is considered in which the plasma is flowing in the z-direction along the magnetic field B sub 0 with a velocity V sub 0. As far as the velocity is concerned two different velocity profiles, with different hydrodynmaic stability properties are discussed. The results are summarized.

Energy Research Highlights-2

ScienceCinema

None

2018-01-16

Highlights the research NETL is doing in the following fields: Clean Coal, Gasification, Carbon Sequestration, and Hydrogen. This video was featured in the lobby of the Forrestal building in Washington, D.C.

The Decisions of Elementary School Principals: A Test of Ideal Type Methodology.

ERIC Educational Resources Information Center

Greer, John T.

Interviews with 25 Georgia elementary school principals provided data that could be used to test an application of Max Weber's ideal type methodology to decision-making. Alfred Schuetz's model of the rational act, based on one of Weber's ideal types, was analyzed and translated into describable acts and behaviors. Interview procedures were…

Turkish Primary Science Teachers' Perceptions of an Ideal Teacher Education System

ERIC Educational Resources Information Center

Korkmaz, Hunkar; Altindag, Ahmet

2017-01-01

The goals of this descriptive study were to determine Turkish pre-service science teachers' perceptions of an ideal teacher education system. The sample consisted of 137 pre-service teachers, including 74 females and 63 males. The questionnaire was based on open-ended questions and was developed to investigate ideal teacher education system…

Keeping the Bar Low: Why Russia's Nonresident Fathers Accept Narrow Fatherhood Ideals

ERIC Educational Resources Information Center

Utrata, Jennifer

2008-01-01

Although most Russian nonresident fathers feel torn between old and new ideals of fatherhood, they end up accepting older, narrow ideals. Fathers reproduce the dominant gender discourse, which deems men irresponsible and infantile and diminishes the importance of fathers. On the basis of extensive fieldwork, including in-depth interviews (N = 21)…

Laboratory for Atmospheres: 2006 Technical Highlights

NASA Technical Reports Server (NTRS)

Stewart, Richard W.

2007-01-01

The 2006 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, are highlighted in this report.

Laboratory for Atmospheres 2009 Technical Highlights

NASA Technical Reports Server (NTRS)

Cote, Charles E.

2010-01-01

The 2009 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

Laboratory for Atmospheres 2005 Technical Highlights

NASA Technical Reports Server (NTRS)

2006-01-01

The 2005 Technical highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

Laboratory for Atmospheres 2010 Technical Highlights

NASA Technical Reports Server (NTRS)

2011-01-01

The 2010 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

Laboratory for Atmospheres 2007 Technical Highlights

NASA Technical Reports Server (NTRS)

Stewart, Richard W.

2008-01-01

The 2007 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

Is it possible to define the ideal lips?

PubMed

Kar, M; Muluk, N B; Bafaqeeh, S A; Cingi, C

2018-02-01

The lips are an essential component of the symmetry and aesthetics of the face. Cosmetic surgery to modify the lips has recently gained in popularity, but the results are in some cases disasterous. In this review, we describe the features of the ideal lips for an individual's face. The features of the ideal lips with respect to facial anatomy, important anatomical landmarks of the face, the facial proportions of the lips and ethnic and sexual differences are described. The projection and relative sizes of the upper and lower lips are as significant to lip aesthetics as the proportion of the lips to the rest of the facial structure. Robust, pouty lips are considered to be sexually attractive by both males and females. Horizontal thirds and the golden ratio describe the proportions that contribute to the beauty and attractiveness of the lips. In young Caucasians, the ideal ratio of the vertical height of the upper lip to that of the lower lip is 1:1.6. Blacks, genetically, have a greater lip volume. The shape and volume of a person's lips are of great importance in the perception of beauty by humans. The appearance of the lips in part determines the attractiveness of a person's face. In females, fuller lips in relation to facial width as well as greater vermilion height are considered to be attractive. Copyright © 2018 Società Italiana di Otorinolaringologia e Chirurgia Cervico-Facciale, Rome, Italy.

Determination of JWL Parameters for Non-Ideal Explosive

NASA Astrophysics Data System (ADS)

Hamashima, H.; Kato, Y.; Itoh, S.

2004-07-01

JWL equation of state is widely used in numerical simulation of detonation phenomena. JWL parameters are determined by cylinder test. Detonation characteristics of non-ideal explosive depend strongly on confinement, and JWL parameters determined by cylinder test do not represent the state of detonation products in many applications. We developed a method to determine JWL parameters from the underwater explosion test. JWL parameters were determined through a method of characteristics applied to the configuration of the underwater shock waves of cylindrical explosives. The numerical results obtained using JWL parameters determined by the underwater explosion test and those obtained using JWL parameters determined by cylinder test were compared with experimental results for typical non-ideal explosive; emulsion explosive. Good agreement was confirmed between the results obtained using JWL parameters determined by the underwater explosion test and experimental results.

Epi-Two-Dimensional Fluid Flow: A New Topological Paradigm for Dimensionality