Two-fluid turbulence including electron inertia
Energy Technology Data Exchange (ETDEWEB)
Andrés, Nahuel, E-mail: nandres@iafe.uba.ar; Gómez, Daniel [Instituto de Astronomía y Física del Espacio, CC. 67, suc. 28, 1428 Buenos Aires (Argentina); Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón I, 1428 Buenos Aires (Argentina); Gonzalez, Carlos; Martin, Luis; Dmitruk, Pablo [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, 1428 Buenos Aires (Argentina)
2014-12-15
We present a full two-fluid magnetohydrodynamic (MHD) description for a completely ionized hydrogen plasma, retaining the effects of the Hall current, electron pressure, and electron inertia. According to this description, each plasma species introduces a new spatial scale: the ion inertial length λ{sub i} and the electron inertial length λ{sub e}, which are not present in the traditional MHD description. In the present paper, we seek for possible changes in the energy power spectrum in fully developed turbulent regimes, using numerical simulations of the two-fluid equations in two-and-a-half dimensions. We have been able to reproduce different scaling laws in different spectral ranges, as it has been observed in the solar wind for the magnetic energy spectrum. At the smallest wavenumbers where plain MHD is valid, we obtain an inertial range following a Kolmogorov k{sup −5∕3} law. For intermediate wavenumbers such that λ{sub i}{sup −1}≪k≪λ{sub e}{sup −1}, the spectrum is modified to a k{sup −7∕3} power-law, as has also been obtained for Hall-MHD neglecting electron inertia terms. When electron inertia is retained, a new spectral region given by k>λ{sub e}{sup −1} arises. The power spectrum for magnetic energy in this region is given by a k{sup −11∕3} power law. Finally, when the terms of electron inertia are retained, we study the self-consistent electric field. Our results are discussed and compared with those obtained in the solar wind observations and previous simulations.
Independent particle Schroedinger Fluid: moments of inertia
International Nuclear Information System (INIS)
Kan, K.K.; Griffin, J.J.
1977-10-01
This philosophy of the Single Particle Schroedinger Fluid, especially as regards the velocity fields which find such a natural role therein, is applied to the study of the moments of inertia of independent Fermion system. It is shown that three simplified systems exhibit the rigid-body rotational velocity field in the limit of large A, and that the leading deviations, both on the average and fluctuating, from this large A limit can be described analytically, and verified numerically. For a single particle in a Hill-Wheeler box the moments are studied numerically, and their large fluctuations identified with the specific energy level degeneracies of its parallelepiped shape. The full assemblage of these new and old results is addressed to the question of the necessary and sufficient condition that the moment have the rigid value. Counterexamples are utilized to reject some conditions, and the conjecture is argued that Unconstrained Shape Equilibrium might be the necessary and sufficient condition. The spheroidal square well problem is identified as a promising test case
Inertia effects in the laminar radial flow of a power law fluid with an electromagnetic field
International Nuclear Information System (INIS)
Chen, C.-K.; Chen, K.-H.; Wu, C.-Y.
1984-01-01
An approximate study of the pressure distribution for the radial flow of a non-newtonian (power law) fluid between two parallel disks in the presence of an axial electrical field is obtained by using the momentum and energy integral methods. For a non-newtonian fluid it is shown that the inertia effect must be considered to be significant for the pressure distribution, especially for the power law fluids with n >= 1. Furthermore, it is seen that the inertia effect will also lower the load capacity of the disks. (Auth.)
A Review on Inertia and Linear Friction Welding of Ni-Based Superalloys
Chamanfar, Ahmad; Jahazi, Mohammad; Cormier, Jonathan
2015-04-01
Inertia and linear friction welding are being increasingly used for near-net-shape manufacturing of high-value materials in aerospace and power generation gas turbines because of providing a better quality joint and offering many advantages over conventional fusion welding and mechanical joining techniques. In this paper, the published works up-to-date on inertia and linear friction welding of Ni-based superalloys are reviewed with the objective to make clarifications on discrepancies and uncertainties reported in literature regarding issues related to these two friction welding processes as well as microstructure, texture, and mechanical properties of the Ni-based superalloy weldments. Initially, the chemical composition and microstructure of Ni-based superalloys that contribute to the quality of the joint are reviewed briefly. Then, problems related to fusion welding of these alloys are addressed with due consideration of inertia and linear friction welding as alternative techniques. The fundamentals of inertia and linear friction welding processes are analyzed next with emphasis on the bonding mechanisms and evolution of temperature and strain rate across the weld interface. Microstructural features, texture development, residual stresses, and mechanical properties of similar and dissimilar polycrystalline and single crystal Ni-based superalloy weldments are discussed next. Then, application of inertia and linear friction welding for joining Ni-based superalloys and related advantages over fusion welding, mechanical joining, and machining are explained briefly. Finally, present scientific and technological challenges facing inertia and linear friction welding of Ni-based superalloys including those related to modeling of these processes are addressed.
Four-dimensional Hooke's law can encompass linear elasticity and inertia
International Nuclear Information System (INIS)
Antoci, S.; Mihich, L.
1999-01-01
The question is examined whether the formally straightforward extension of Hooke's time-honoured stress-strain relation to the four dimensions of special and of general relativity can make physical sense. The four-dimensional Hooke law is found able to account for the inertia of matter; in the flat-space, slow-motion approximation the field equations for the displacement four-vector field ξ i can encompass both linear elasticity and inertia. In this limit one just recovers the equations of motion of the classical theory of elasticity
Effect of rotary inertia of concentrated masses on the natural vibration of fluid conveying pipes
International Nuclear Information System (INIS)
Kang, Myeong Gie
1999-01-01
Effects of the rotary inertia of concentrated masses on the natural vibrations of fluid conveying pipes have been studied by theoretical modeling and computer simulation. For analysis, two boundary conditions for pipe ends, simply supported and clamped-clamped, are assumed and Galerkin's method is used for transformation of the governing equation to the eigenvalues problem and the natural frequencies and mode shapes for the system have been calculated by using the newly developed computer code. Moreover, the critical velocities related to a system instability have been investigated. The main conclusions for the present study are (1) rotary inertia gives much change on the higher natural frequencies and mode shapes and its effect is visible when it has small value, (2) The number and location of nodes can be changed by rotary inertia, (3) By introducing rotary inertia, the second natural frequency approaches to the first as the location of the concentrated mass approaches to the midspan of the pipe, and (4) The critical fluid velocities to initiate the system unstable are unchanged by introduction of rotary inertia and the first three velocities are π, 2π, and 3π for the simply supported pipe and 2π, 8.99 and 12.57 for the clamped-clamped pipe. (author). 16 refs., 7 figs., 3 tabs
Bechert, M.; Scheid, B.
2017-11-01
The draw resonance effect appears in fiber spinning processes if the ratio of take-up to inlet velocity, the so-called draw ratio, exceeds a critical value and manifests itself in steady oscillations of flow velocity and fiber diameter. We study the effect of surface tension on the draw resonance behavior of Newtonian fiber spinning in the presence of inertia and gravity. Utilizing an alternative scaling makes it possible to visualize the results in stability maps of highly practical relevance. The interplay of the destabilizing effect of surface tension and the stabilizing effects of inertia and gravity lead to nonmonotonic stability behavior and local stability maxima with respect to the dimensionless fluidity and the dimensionless inlet velocity. A region of unconditional instability caused by the influence of surface tension is found in addition to the region of unconditional stability caused by inertia, which was described in previous works [M. Bechert, D. W. Schubert, and B. Scheid, Eur. J. Mech B 52, 68 (2015), 10.1016/j.euromechflu.2015.02.005; Phys. Fluids 28, 024109 (2016), 10.1063/1.4941762]. Due to its importance for a particular group of fiber spinning applications, a viscous-gravity-surface-tension regime, i.e., negligible effect of inertia, is analyzed separately. The mechanism underlying the destabilizing effect of surface tension is discussed and established stability criteria are tested for validity in the presence of surface tension.
Arasomwan, Martins Akugbe; Adewumi, Aderemi Oluyinka
2013-01-01
Linear decreasing inertia weight (LDIW) strategy was introduced to improve on the performance of the original particle swarm optimization (PSO). However, linear decreasing inertia weight PSO (LDIW-PSO) algorithm is known to have the shortcoming of premature convergence in solving complex (multipeak) optimization problems due to lack of enough momentum for particles to do exploitation as the algorithm approaches its terminal point. Researchers have tried to address this shortcoming by modifying LDIW-PSO or proposing new PSO variants. Some of these variants have been claimed to outperform LDIW-PSO. The major goal of this paper is to experimentally establish the fact that LDIW-PSO is very much efficient if its parameters are properly set. First, an experiment was conducted to acquire a percentage value of the search space limits to compute the particle velocity limits in LDIW-PSO based on commonly used benchmark global optimization problems. Second, using the experimentally obtained values, five well-known benchmark optimization problems were used to show the outstanding performance of LDIW-PSO over some of its competitors which have in the past claimed superiority over it. Two other recent PSO variants with different inertia weight strategies were also compared with LDIW-PSO with the latter outperforming both in the simulation experiments conducted. PMID:24324383
International Nuclear Information System (INIS)
Radiom, Milad; Ducker, William; Robbins, Brian; Paul, Mark
2015-01-01
The hydrodynamic interaction of two closely spaced micron-scale spheres undergoing Brownian motion was measured as a function of their separation. Each sphere was attached to the distal end of a different atomic force microscopy cantilever, placing each sphere in a stiff one-dimensional potential (0.08 Nm −1 ) with a high frequency of thermal oscillations (resonance at 4 kHz). As a result, the sphere’s inertial and restoring forces were significant when compared to the force due to viscous drag. We explored interparticle gap regions where there was overlap between the two Stokes layers surrounding each sphere. Our experimental measurements are the first of their kind in this parameter regime. The high frequency of oscillation of the spheres means that an analysis of the fluid dynamics would include the effects of fluid inertia, as described by the unsteady Stokes equation. However, we find that, for interparticle separations less than twice the thickness of the wake of the unsteady viscous boundary layer (the Stokes layer), the hydrodynamic interaction between the Brownian particles is well-approximated by analytical expressions that neglect the inertia of the fluid. This is because elevated frictional forces at narrow gaps dominate fluid inertial effects. The significance is that interparticle collisions and concentrated suspensions at this condition can be modeled without the need to incorporate fluid inertia. We suggest a way to predict when fluid inertial effects can be ignored by including the gap-width dependence into the frequency number. We also show that low frequency number analysis can be used to determine the microrheology of mixtures at interfaces
Enhanced inertia from lossy effective fluids using multi-scale sonic crystals
Directory of Open Access Journals (Sweden)
Matthew D. Guild
2014-12-01
Full Text Available In this work, a recent theoretically predicted phenomenon of enhanced permittivity with electromagnetic waves using lossy materials is investigated for the analogous case of mass density and acoustic waves, which represents inertial enhancement. Starting from fundamental relationships for the homogenized quasi-static effective density of a fluid host with fluid inclusions, theoretical expressions are developed for the conditions on the real and imaginary parts of the constitutive fluids to have inertial enhancement, which are verified with numerical simulations. Realizable structures are designed to demonstrate this phenomenon using multi-scale sonic crystals, which are fabricated using a 3D printer and tested in an acoustic impedance tube, yielding good agreement with the theoretical predictions and demonstrating enhanced inertia.
Electron inertia effects for an electron fluid model by the applied-B ion diode
Energy Technology Data Exchange (ETDEWEB)
Gordeev, A V; Levchenko, S V [Kurchatov Institute, Moscow (Russian Federation). Nuclear Fusion Institute
1997-12-31
Numerical calculations within the framework of the one-dimensional vortex-like electron fluid model in applied-B ion diodes, taking account the electron inertia effects, are presented. The existence of the additional relation between the magnetic field and the electric potential offers an opportunity to reduce the ion diode problem to the system of the algebraic equations for the constants introduced. The ion current density in an ion diode is determined only by the magnetic flux cut out by the virtual cathode. As an illustration, the ion diode impedance for the KALIF device was calculated. (author). 2 figs., 6 refs.
Speetjens, M.F.M.; Demissie, E.A.; Metcalfe, G.; Clercx, H.J.H.
2014-01-01
Laminar mixing by the inline-mixing principle is key to many industrial fluids-engineering systems of size extending from microns to meters. However, insight into fundamental transport phenomena particularly under the realistic conditions of three-dimensionality (3D) and fluid inertia remains
The Impact of Convective Fluid Inertia Forces on Operation of Tilting-Pad Journal Bearings
Directory of Open Access Journals (Sweden)
Thomas Hagemann
2017-01-01
Full Text Available This paper presents a combination of experimental data, CFD analyses, and bearing code predictions on emergence of convective inertia fluid forces within the lube oil flow of tilting-pad journal bearings. Concordantly, experimental data and CFD analyses show a significant rise of local pressure at the transition between inlet and leading edge of tilting-pad, especially for high-speed applications with surface speeds up to 100 m/s. This effect can be related to convective inertia forces within fluid flow as cross-sections and flow character rapidly change at the pad entrance. An energy-based approach is implemented in the bearing code in order to provide enhanced boundary conditions for Reynolds equation considering this effect. As a result, predictions of bearing code achieved significant improved correlation with measured pressure distributions and CFD-data. Further, beside the local influence, a nonnegligible impact on characteristic parameters of bearing operation such as maximum temperature and stiffness and damping coefficients is observed. Finally, the results are critically analyzed and requirements to gain more distinct and reliable data are specified.
Swimming of a sphere in a viscous incompressible fluid with inertia
International Nuclear Information System (INIS)
Felderhof, B U; Jones, R B
2017-01-01
The swimming of a sphere immersed in a viscous incompressible fluid with inertia is studied for surface modulations of small amplitude on the basis of the Navier–Stokes equations. The mean swimming velocity and the mean rate of dissipation are expressed as quadratic forms in term of the surface displacements. With a choice of a basis set of modes the quadratic forms correspond to two Hermitian matrices. Optimization of the mean swimming velocity for given rate of dissipation requires the solution of a generalized eigenvalue problem involving the two matrices. It is found for surface modulations of low multipole order that the optimal swimming efficiency depends in intricate fashion on a dimensionless scale number involving the radius of the sphere, the period of the cycle, and the kinematic viscosity of the fluid. (paper)
Swimming of a sphere in a viscous incompressible fluid with inertia
Energy Technology Data Exchange (ETDEWEB)
Felderhof, B U [Institut für Theorie der Statistischen Physik RWTH Aachen University, Templergraben 55, D-52056 Aachen (Germany); Jones, R B, E-mail: ufelder@physik.rwth-aachen.de, E-mail: r.b.jones@qmul.ac.uk [Queen Mary University of London, The School of Physics and Astronomy, Mile End Road, London E1 4NS (United Kingdom)
2017-08-15
The swimming of a sphere immersed in a viscous incompressible fluid with inertia is studied for surface modulations of small amplitude on the basis of the Navier–Stokes equations. The mean swimming velocity and the mean rate of dissipation are expressed as quadratic forms in term of the surface displacements. With a choice of a basis set of modes the quadratic forms correspond to two Hermitian matrices. Optimization of the mean swimming velocity for given rate of dissipation requires the solution of a generalized eigenvalue problem involving the two matrices. It is found for surface modulations of low multipole order that the optimal swimming efficiency depends in intricate fashion on a dimensionless scale number involving the radius of the sphere, the period of the cycle, and the kinematic viscosity of the fluid. (paper)
Swimming of a sphere in a viscous incompressible fluid with inertia
Felderhof, B. U.; Jones, R. B.
2017-08-01
The swimming of a sphere immersed in a viscous incompressible fluid with inertia is studied for surface modulations of small amplitude on the basis of the Navier-Stokes equations. The mean swimming velocity and the mean rate of dissipation are expressed as quadratic forms in term of the surface displacements. With a choice of a basis set of modes the quadratic forms correspond to two Hermitian matrices. Optimization of the mean swimming velocity for given rate of dissipation requires the solution of a generalized eigenvalue problem involving the two matrices. It is found for surface modulations of low multipole order that the optimal swimming efficiency depends in intricate fashion on a dimensionless scale number involving the radius of the sphere, the period of the cycle, and the kinematic viscosity of the fluid.
Bark, David L; Dasi, Lakshmi P
2016-05-01
We examine the influence of the added mass effect (fluid inertia) on mitral valve leaflet stress during isovolumetric phases. To study this effect, oscillating flow is applied to a flexible membrane at various frequencies to control inertia. Resulting membrane strain is calculated through a three-dimensional reconstruction of markers from stereo images. To investigate the effect in vivo, the analysis is repeated on a published dataset for an ovine mitral valve (Journal of Biomechanics 42(16): 2697-2701). The membrane experiment demonstrates that the relationship between pressure and strain must be corrected with a fluid inertia term if the ratio of inertia to pressure differential approaches 1. In the mitral valve, this ratio reaches 0.7 during isovolumetric contraction for an acceleration of 6 m/s(2). Acceleration is reduced by 72% during isovolumetric relaxation. Fluid acceleration also varies along the leaflet during isovolumetric phases, resulting in spatial variations in stress. These results demonstrate that fluid inertia may be the source of the temporally and spatially varying stiffness measurements previously seen through inverse finite element analysis of in vivo data during isovolumetric phases. This study demonstrates that there is a need to account for added mass effects when analyzing in vivo constitutive relationships of heart valves.
Single particle Schroedinger fluid and moments of inertia of deformed nuclei
International Nuclear Information System (INIS)
Doma, S.B.
2002-01-01
The authors have applied the theory of the single-particle Schroedinger fluid to the nuclear collective motion of axially deformed nuclei. A counter example of an arbitrary number of independent nucleons in the anisotropic harmonic oscillator potential at the equilibrium deformation has been also given. Moreover, the ground states of the doubly even nuclei in the s-d shell 20 Ne, 24 Mg, 28 Si, 32 S and 36 Ar are constructed by filling the single-particle states corresponding to the possible values of the number of quanta of excitations n x , n y and n z . Accordingly, the cranking-model, the rigid-body model and the equilibrium-model moments of inertia of these nuclei are calculated as functions of the oscillator parameters ℎω x , ℎω y and ℎω z which are given in terms of the non deformed value ℎω 0 0 , depending on the mass number A, the number of neutrons N, the number of protons Z, and the deformation parameter β. The calculated values of the cranking-model moments of inertia of these nuclei are in good agreement with the corresponding experiential values and show that the considered axially deformed nuclei may have oblate as well as prolate shapes and that the nucleus 24 Mg is the only one which is highly deformed. The rigid-body model and the equilibrium-model moments of inertia of the two nuclei 20 Ne and 24 Mg are also in good agreement with the corresponding experimental values
Kinematics of a Fluid Ellipse in a Linear Flow
Directory of Open Access Journals (Sweden)
Jonathan M. Lilly
2018-02-01
Full Text Available A four-parameter kinematic model for the position of a fluid parcel in a time-varying ellipse is introduced. For any ellipse advected by an arbitrary linear two-dimensional flow, the rates of change of the ellipse parameters are uniquely determined by the four parameters of the velocity gradient matrix, and vice versa. This result, termed ellipse/flow equivalence, provides a stronger version of the well-known result that a linear velocity field maps an ellipse into another ellipse. Moreover, ellipse/flow equivalence is shown to be a manifestation of Stokes’ theorem. This is done by deriving a matrix-valued extension of the classical Stokes’ theorem that involves a spatial integral over the velocity gradient tensor, thus accounting for the two strain terms in addition to the divergence and vorticity. General expressions for various physical properties of an elliptical ring of fluid are also derived. The ellipse kinetic energy is found to be composed of three portions, associated respectively with the circulation, the rate of change of the moment of inertia, and the variance of parcel angular velocity around the ellipse. A particular innovation is the use of four matrices, termed the I J K L basis, that greatly facilitate the required calculations.
Local linear viscoelasticity of confined fluids.
Hansen, J S; Daivis, P J; Todd, B D
2007-04-14
In this paper the authors propose a novel method to study the local linear viscoelasticity of fluids confined between two walls. The method is based on the linear constitutive equation and provides details about the real and imaginary parts of the local complex viscosity. They apply the method to a simple atomic fluid undergoing zero mean oscillatory flow using nonequilibrium molecular dynamics simulations. The method shows that the viscoelastic properties of the fluid exhibit dramatic spatial changes near the wall-fluid boundary due to the high density in this region. It is also shown that the real part of the viscosity converges to the frequency dependent local shear viscosity sufficiently far away from the wall. This also provides valuable information about the transport properties in the fluid, in general. The viscosity is compared with predictions from the local average density model. The two methods disagree in that the local average density model predicts larger viscosity variations near the wall-fluid boundary than what is observed through the method presented here.
Duran-Olivencia, Miguel A.; Goddard, Ben; Kalliadasis, Serafim
2015-11-01
Over the last few decades the classical density-functional theory (DFT) and its dynamic extensions (DDFTs) have become a remarkably powerful tool in the study of colloidal fluids. Recently there has been extensive research to generalise all previous DDFTs finally yielding a general DDFT equation (for spherical particles) which takes into account both inertia and hydrodynamic interactions (HI) which strongly influence non-equilibrium properties. The present work will be devoted to a further generalisation of such a framework to systems of anisotropic particles. To this end, the kinetic equation for the Brownian particle distribution function is derived starting from the Liouville equation and making use of Zwanzig's projection-operator techniques. By averaging over all but one particle, a DDFT equation is finally obtained with some similarities to that for spherical colloids. However, there is now an inevitable translational-rotational coupling which affects the diffusivity of asymmetric particles. Lastly, in the overdamped (high friction) limit the theory is notably simplified leading to a DDFT equation which agrees with previous derivations. We acknowledge financial support from European Research Council via Advanced Grant No. 247031.
Solution of the spherically symmetric linear thermoviscoelastic problem in the inertia-free limit
DEFF Research Database (Denmark)
Christensen, Tage Emil; Dyre, J. C.
2008-01-01
paper-the thermoviscoelastic problem may be solved analytically in the inertia-free limit, i.e., the limit where the sample is much smaller than the wavelength of sound waves at the frequencies of interest. As for the one-dimensional thermoviscoelastic problem [Christensen et al., Phys. Rev. E 75...
Thouless-Valatin rotational moment of inertia from linear response theory
Petrík, Kristian; Kortelainen, Markus
2018-03-01
Spontaneous breaking of continuous symmetries of a nuclear many-body system results in the appearance of zero-energy restoration modes. These so-called spurious Nambu-Goldstone modes represent a special case of collective motion and are sources of important information about the Thouless-Valatin inertia. The main purpose of this work is to study the Thouless-Valatin rotational moment of inertia as extracted from the Nambu-Goldstone restoration mode that results from the zero-frequency response to the total-angular-momentum operator. We examine the role and effects of the pairing correlations on the rotational characteristics of heavy deformed nuclei in order to extend our understanding of superfluidity in general. We use the finite-amplitude method of the quasiparticle random-phase approximation on top of the Skyrme energy density functional framework with the Hartree-Fock-Bogoliubov theory. We have successfully extended this formalism and established a practical method for extracting the Thouless-Valatin rotational moment of inertia from the strength function calculated in the symmetry-restoration regime. Our results reveal the relation between the pairing correlations and the moment of inertia of axially deformed nuclei of rare-earth and actinide regions of the nuclear chart. We have also demonstrated the feasibility of the method for obtaining the moment of inertia for collective Hamiltonian models. We conclude that from the numerical and theoretical perspective, the finite-amplitude method can be widely used to effectively study rotational properties of deformed nuclei within modern density functional approaches.
International Nuclear Information System (INIS)
Speetjens, M. F. M.; Demissie, E. A.; Metcalfe, G.; Clercx, H. J. H.
2014-01-01
Laminar mixing by the inline-mixing principle is a key to many industrial fluids-engineering systems of size extending from micrometers to meters. However, insight into fundamental transport phenomena particularly under the realistic conditions of three-dimensionality (3D) and fluid inertia remains limited. This study addresses these issues for inline mixers with cylindrical geometries and adopts the Rotated Arc Mixer (RAM) as a representative system. Transport is investigated from a Lagrangian perspective by identifying and examining coherent structures that form in the 3D streamline portrait. 3D effects and fluid inertia introduce three key features that are not found in simplified configurations: transition zones between consecutive mixing cells of the inline-mixing flow; local upstream flow (in certain parameter regimes); transition/inertia-induced breaking of symmetries in the Lagrangian equations of motion (causing topological changes in coherent structures). Topological considerations strongly suggest that there nonetheless always exists a net throughflow region between inlet and outlet of the inline-mixing flow that is strictly separated from possible internal regions. The Lagrangian dynamics in this region admits representation by a 2D time-periodic Hamiltonian system. This establishes one fundamental kinematic structure for the present class of inline-mixing flows and implies universal behavior in that all states follow from the Hamiltonian breakdown of one common integrable state. A so-called period-doubling bifurcation is the only way to eliminate transport barriers originating from this state and thus is a necessary (yet not sufficient) condition for global chaos. Important in a practical context is that a common simplification in literature, i.e., cell-wise fully-developed Stokes flow (“2.5D approach”), retains these fundamental kinematic properties and deviates from the generic 3D inertial case only in a quantitative sense. This substantiates its
Inertia effects in rheometrical flow systems
Waterman, H.A.
1976-01-01
The flow field of a linear viscoelastic material in the orthogonal rheometer, taking fluid inertia into account, has been studied theoretically and an exact solution is given. The flow field of a Newtonian liquid is included in this solution as a special case. The forces on the plates are readily
van Putten, M.; Zeelenberg, M.; van Dijk, E.; Tykocinski, O.E.
2013-01-01
Inaction inertia occurs when bypassing an initial action opportunity has the effect of decreasing the likelihood that subsequent similar action opportunities will be taken. This overview of the inaction inertia literature demonstrates the impact of inaction inertia on decision making. Based on
Stability of non-linear constitutive formulations for viscoelastic fluids
Siginer, Dennis A
2014-01-01
Stability of Non-linear Constitutive Formulations for Viscoelastic Fluids provides a complete and up-to-date view of the field of constitutive equations for flowing viscoelastic fluids, in particular on their non-linear behavior, the stability of these constitutive equations that is their predictive power, and the impact of these constitutive equations on the dynamics of viscoelastic fluid flow in tubes. This book gives an overall view of the theories and attendant methodologies developed independently of thermodynamic considerations as well as those set within a thermodynamic framework to derive non-linear rheological constitutive equations for viscoelastic fluids. Developments in formulating Maxwell-like constitutive differential equations as well as single integral constitutive formulations are discussed in the light of Hadamard and dissipative type of instabilities.
Inertia effects in rheometrical flow systems Part 2: The balance rheometer
Waterman, H.A.
1976-01-01
The flow field of a linear viscoelastic fluid in the balance rheometer, taking fluid inertia into account, has been studied theoretically and an exact solution is given. The flow field of a Newtonian fluid is included in this solution as a special case. The forces and couples on the hemispheres are
Non-linear seismic analysis of structures coupled with fluid
International Nuclear Information System (INIS)
Descleve, P.; Derom, P.; Dubois, J.
1983-01-01
This paper presents a method to calculate non-linear structure behaviour under horizontal and vertical seismic excitation, making possible the full non-linear seismic analysis of a reactor vessel. A pseudo forces method is used to introduce non linear effects and the problem is solved by superposition. Two steps are used in the method: - Linear calculation of the complete model. - Non linear analysis of thin shell elements and calculation of seismic induced pressure originating from linear and non linear effects, including permanent loads and thermal stresses. Basic aspects of the mathematical formulation are developed. It has been applied to axi-symmetric shell element using a Fourier series solution. For the fluid interaction effect, a comparison is made with a dynamic test. In an example of application, the displacement and pressure time history are given. (orig./GL)
Expressions for linearized perturbations in ideal-fluid cosmological models
International Nuclear Information System (INIS)
Ratra, B.
1988-01-01
We present closed-form solutions of the relativistic linear perturbation equations (in synchronous gauge) that govern the evolution of inhomogeneities in homogeneous, spatially flat, ideal-fluid, cosmological models. These expressions, which are valid for irregularities on any scale, allow one to analytically interpolate between the known approximate solutions which are valid at early times and at late times
Non-linear oscillations of fluid in a container
Verhagen, J.H.G.; van Wijngaarden, L.
1965-01-01
This paper is concerned with forced oscillations of fluid in a rectangular container. From the linearized approximation of the equations governing these oscillations, resonance frequencies are obtained for which the amplitude of the oscillations becomes infinite. Observation shows that under these
Linear and nonlinear analysis of fluid slosh dampers
Sayar, B. A.; Baumgarten, J. R.
1982-11-01
A vibrating structure and a container partially filled with fluid are considered coupled in a free vibration mode. To simplify the mathematical analysis, a pendulum model to duplicate the fluid motion and a mass-spring dashpot representing the vibrating structure are used. The equations of motion are derived by Lagrange's energy approach and expressed in parametric form. For a wide range of parametric values the logarithmic decrements of the main system are calculated from theoretical and experimental response curves in the linear analysis. However, for the nonlinear analysis the theoretical and experimental response curves of the main system are compared. Theoretical predictions are justified by experimental observations with excellent agreement. It is concluded finally that for a proper selection of design parameters, containers partially filled with viscous fluids serve as good vibration dampers.
Linear and nonlinear viscous flow in two-dimensional fluids
International Nuclear Information System (INIS)
Gravina, D.; Ciccotti, G.; Holian, B.L.
1995-01-01
We report on molecular dynamics simulations of shear viscosity η of a dense two-dimensional fluid as a function of the shear rate γ. We find an analytic dependence of η on γ, and do not find any evidence whatsoever of divergence in the Green-Kubo (GK) value that would be caused by the well-known long-time tail for the shear-stress autocorrelation function, as predicted by the mode-coupling theory. In accordance with the linear response theory, the GK value of η agrees remarkably well with nonequilibrium values at small shear rates. (c) 1995 The American Physical Society
Felderhof, B. U.
2017-09-01
Translational and rotational swimming at small Reynolds numbers of a planar assembly of identical spheres immersed in an incompressible viscous fluid is studied on the basis of a set of equations of motion for the individual spheres. The motion of the spheres is caused by actuating forces and forces derived from a direct interaction potential, as well as hydrodynamic forces exerted by the fluid as frictional and added mass hydrodynamic interactions. The translational and rotational swimming velocities of the assembly are deduced from momentum and angular momentum balance equations. The mean power required during a period is calculated from an instantaneous power equation. Expressions are derived for the mean swimming velocities and the mean power, valid to second order in the amplitude of displacements from the relative equilibrium positions. Hence these quantities can be evaluated for prescribed periodic displacements. Explicit calculations are performed for three spheres interacting such that they form an equilateral triangle in the rest frame of the configuration.
Fluid-structure interactions in one-dimensional linear cases
International Nuclear Information System (INIS)
Schumann, U.
1979-01-01
The interaction of pressure waves in a pipe with an elastic endwall (piston) is analyzed using a linear ('acoustic') model. Two transient and two periodic cases are investigated. In the transient cases the motions are initiated by either a sudden pressure drop at the opeen end (breaking membrane) or by a sudden release of the piston from a non-equilibrium position ('snapback'); in the latter case the other end of the pipe is closed. In the periodic cases harmonic oscillations of the piston and the fluid are investigated with the other end of the pipe being either closed or open (kept at constant pressure). The problem is characterized by three non-dimensional numbers (e.g.: Mach-, Strouhal-, and an interaction-number). The solution of the wave equation for the pressure accounting for the coupling to the structure can be reduced analytically to the problem of integrating one ordinary differential equation of second order in time. This differential equation in turn can be integrated analytically at least for a certain time period. At later times this ordinary differential equation is integrated numerically. For the periodic cases eigenvalue-problems arise with an infinite number of solutions. The first few eigensolutions are given. (orig./RW) [de
Felderhof, B. U.
2015-11-01
A mechanical model of swimming and flying in an incompressible viscous fluid in the absence of gravity is studied on the basis of assumed equations of motion. The system is modeled as an assembly of rigid spheres subject to elastic direct interactions and to periodic actuating forces which sum to zero. Hydrodynamic interactions are taken into account in the virtual mass matrix and in the friction matrix of the assembly. An equation of motion is derived for the velocity of the geometric center of the assembly. The mean power is calculated as the mean rate of dissipation. The full range of viscosity is covered, so that the theory can be applied to the flying of birds, as well as to the swimming of fish or bacteria. As an example a system of three equal spheres moving along a common axis is studied.
Two-fluid static spherical configurations with linear mass function in the Einstein-Cartan theory
International Nuclear Information System (INIS)
Gallakhmetov, A.M.
2002-01-01
In the framework of the Einstein-Cartan theory, two-fluid static spherical configurations with linear mass function are considered. One of these modelling anisotropic matter distributions within star and the other fluid is a perfect fluid representing a source of torsion. It is shown that the solutions of the Einstein equations for anisotropic relativistic spheres in General Relativity may generate the solutions in the Einstein-Cartan theory. Some exact solutions are obtained
Linear waves in two-fluid relativistic gasdynamics
International Nuclear Information System (INIS)
Gavrikov, M.B.; Solov'ev, L.S.
1988-01-01
This paper is devoted to the development of a theory of waves propagating in a two-component gaseous medium. In all cases considered the authors use only the method of two-fluid relativistic electromagnetic gasdynamics in the framework of the special relativity theory. They pay special attention to the problem of the interaction in a mixture of both neutral and charged gases when they move relative to one another. This interaction is for charged gases responsible for the appearance of ohmic resistance to an electrical current
Alós-Ferrer, Carlos; Hügelschäfer, Sabine; Li, Jiahui
2016-01-01
Decision inertia is the tendency to repeat previous choices independently of the outcome, which can give rise to perseveration in suboptimal choices. We investigate this tendency in probability-updating tasks. Study 1 shows that, whenever decision inertia conflicts with normatively optimal behavior (Bayesian updating), error rates are larger and decisions are slower. This is consistent with a dual-process view of decision inertia as an automatic process conflicting with a more rational, controlled one. We find evidence of decision inertia in both required and autonomous decisions, but the effect of inertia is more clear in the latter. Study 2 considers more complex decision situations where further conflict arises due to reinforcement processes. We find the same effects of decision inertia when reinforcement is aligned with Bayesian updating, but if the two latter processes conflict, the effects are limited to autonomous choices. Additionally, both studies show that the tendency to rely on decision inertia is positively associated with preference for consistency.
Revisited global drift fluid model for linear devices
International Nuclear Information System (INIS)
Reiser, Dirk
2012-01-01
The problem of energy conserving global drift fluid simulations is revisited. It is found that for the case of cylindrical plasmas in a homogenous magnetic field, a straightforward reformulation is possible avoiding simplifications leading to energetic inconsistencies. The particular new feature is the rigorous treatment of the polarisation drift by a generalization of the vorticity equation. The resulting set of model equations contains previous formulations as limiting cases and is suitable for efficient numerical techniques. Examples of applications on studies of plasma blobs and its impact on plasma target interaction are presented. The numerical studies focus on the appearance of plasma blobs and intermittent transport and its consequences on the release of sputtered target materials in the plasma. Intermittent expulsion of particles in radial direction can be observed and it is found that although the neutrals released from the target show strong fluctuations in their propagation into the plasma column, the overall effect on time averaged profiles is negligible for the conditions considered. In addition, the numerical simulations are utilised to perform an a-posteriori assessment of the magnitude of energetic inconsistencies in previously used simplified models. It is found that certain popular approximations, in particular by the use of simplified vorticity equations, do not significantly affect energetics. However, popular model simplifications with respect to parallel advection are found to provide significant deterioration of the model consistency.
Knotted solutions for linear and nonlinear theories: Electromagnetism and fluid dynamics
Directory of Open Access Journals (Sweden)
Daniel W.F. Alves
2017-10-01
Full Text Available We examine knotted solutions, the most simple of which is the “Hopfion”, from the point of view of relations between electromagnetism and ideal fluid dynamics. A map between fluid dynamics and electromagnetism works for initial conditions or for linear perturbations, allowing us to find new knotted fluid solutions. Knotted solutions are also found to be solutions of nonlinear generalizations of electromagnetism, and of quantum-corrected actions for electromagnetism coupled to other modes. For null configurations, electromagnetism can be described as a null pressureless fluid, for which we can find solutions from the knotted solutions of electromagnetism. We also map them to solutions of Euler's equations, obtained from a type of nonrelativistic reduction of the relativistic fluid equations.
Automated finder for the critical condition on the linear stability of fluid motions
International Nuclear Information System (INIS)
Fujimura, Kaoru
1990-03-01
An automated finder routine for the critical condition on the linear stability of fluid motions is proposed. The Newton-Raphson method was utilized for an iteration to solve nonlinear eigenvalue problems appeared in the analysis. The routine was applied to linear stability problem of a free convection between vertical parallel plates with different non-uniform temperatures as well as a plane Poiseuille flow. An efficiency of the finder routine is demonstrated for several parameter sets, numerically. (author)
Treating inertia in passive microbead rheology.
Indei, Tsutomu; Schieber, Jay D; Córdoba, Andrés; Pilyugina, Ekaterina
2012-02-01
The dynamic modulus G(*) of a viscoelastic medium is often measured by following the trajectory of a small bead subject to Brownian motion in a method called "passive microbead rheology." This equivalence between the positional autocorrelation function of the tracer bead and G(*) is assumed via the generalized Stokes-Einstein relation (GSER). However, inertia of both bead and medium are neglected in the GSER so that the analysis based on the GSER is not valid at high frequency where inertia is important. In this paper we show how to treat both contributions to inertia properly in one-bead passive microrheological analysis. A Maxwell fluid is studied as the simplest example of a viscoelastic fluid to resolve some apparent paradoxes of eliminating inertia. In the original GSER, the mean-square displacement (MSD) of the tracer bead does not satisfy the correct initial condition. If bead inertia is considered, the proper initial condition is realized, thereby indicating an importance of including inertia, but the MSD oscillates at a time regime smaller than the relaxation time of the fluid. This behavior is rather different from the original result of the GSER and what is observed. What is more, the discrepancy from the GSER result becomes worse with decreasing bead mass, and there is an anomalous gap between the MSD derived by naïvely taking the zero-mass limit in the equation of motion and the MSD for finite bead mass as indicated by McKinley et al. [J. Rheol. 53, 1487 (2009)]. In this paper we show what is necessary to take the zero-mass limit of the bead safely and correctly without causing either the inertial oscillation or the anomalous gap, while obtaining the proper initial condition. The presence of a very small purely viscous element can be used to eliminate bead inertia safely once included in the GSER. We also show that if the medium contains relaxation times outside the window where the single-mode Maxwell behavior is observed, the oscillation can be
Finite element procedures for coupled linear analysis of heat transfer, fluid and solid mechanics
Sutjahjo, Edhi; Chamis, Christos C.
1993-01-01
Coupled finite element formulations for fluid mechanics, heat transfer, and solid mechanics are derived from the conservation laws for energy, mass, and momentum. To model the physics of interactions among the participating disciplines, the linearized equations are coupled by combining domain and boundary coupling procedures. Iterative numerical solution strategy is presented to solve the equations, with the partitioning of temporal discretization implemented.
2001-01-01
This image shows the global thermal inertia of the Martian surface as measured by the Thermal Emission Spectrometer (TES) instrument on the Mars Global Surveyor. The data were acquired during the first 5000 orbits of the MGS mapping mission. The pattern of inertia variations observed by TES agrees well with the thermal inertia maps made by the Viking Infrared Thermal Mapper experiment, but the TES data shown here are at significantly higher spatial resolution (15 km versus 60 km).The TES instrument was built by Santa Barbara Remote Sensing and is operated by Philip R. Christensen, of Arizona State University, Tempe, AZ.
Growth, unemployment and wage inertia
Raurich, Xavier; Sorolla, Valeri
2014-01-01
We introduce wage setting via efficiency wages in the neoclassical one-sector growth model to study the growth effects of wage inertia. We compare the dynamic equilibrium of an economy with wage inertia with the equilibrium of an economy without wage inertia. We show that wage inertia affects the long run employment rate and that the transitional dynamics of the main economic variables will be different because wages are a state variable when wage inertia is introduced. In particular, we show...
B. Koren (Barry); M.R. Lewis; E.H. van Brummelen (Harald); B. van Leer
2001-01-01
textabstractA finite-volume method is presented for the computation of compressible flows of two immiscible fluids at very different densities. The novel ingredient in the method is a two-fluid linearized Godunov scheme, allowing for flux computations in case of different fluids (e.g., water and
Linear study of Kelvin-Helmholtz instability for a viscous compressible fluid
International Nuclear Information System (INIS)
Hallo, L.; Gauthier, S.
1992-01-01
The linear phase of the process leading to a developed turbulence is particularly important for the study of flow stability. A Galerkin spectral method adapted to the study of the mixture layer of one fluid is proposed from a sheared initial velocity profile. An algebraic mapping is developed to improve accuracy near high gradient zone. Validation is obtained by analytic methods for non-viscous flow and multi-domain spectral methods for viscous and compressible flow. Rates of growth are presented for subsonic and slightly supersonic flow. An extension of the method is presented for the study of the linear stability of a mixture with variable concentration and transport properties
Acquisition of Inertia by a Moving Crack
Goldman, Tamar; Livne, Ariel; Fineberg, Jay
2010-03-01
We experimentally investigate the dynamics of “simple” tensile cracks. Within an effectively infinite medium, a crack’s dynamics perfectly correspond to inertialess behavior predicted by linear elastic fracture mechanics. Once a crack interacts with waves that it generated at earlier times, this description breaks down. Cracks then acquire inertia and sluggishly accelerate. Crack inertia increases with crack speed v and diverges as v approaches its limiting value. We show that these dynamics are in excellent accord with an equation of motion derived in the limit of an infinite strip [M. Marder, Phys. Rev. Lett. 66, 2484 (1991)PRLTAO0031-900710.1103/PhysRevLett.66.2484].
Bounds on the moment of inertia of nonrotating neutron stars
International Nuclear Information System (INIS)
Sabbadini, A.G.; Hartle, J.B.
1977-01-01
Upper and lower bounds are placed on the moments of inertia of relativistic, spherical, perfect fluid neutron stars assuming that the pressure p and density p are positive and that (dp/drho) is positive. Bounds are obtained (a) for the moment of inertia of a star with given mass and radius, (b) for the moment of inertia of neutron stars for which the equation of state is known below a given density rho/sub omicron/and (c) for the mass-moment of inertia relation for stars whose equation of state is known below a given density rho/sub omicron/The bounds are optimum ones in the sense that there always exists a configuration consistent with the assumptions having a moment of inertia equal to that of the bound. The implications of the results for the maximum mass of slowly rotating neutron stars are discussed
Simulations of fluid flow through porous media based on cellular automata and non-linear dynamics
Energy Technology Data Exchange (ETDEWEB)
Paulson, K V
1992-05-15
A study is being carried out to apply cellular automata and non-linear dynamics in the construction of efficient and accurate computer simulations of multiphase fluid flow through porous media, with the objective of application to reservoir modelling for hydrocarbon recovery. An algorithm based on Boolean operations has been developed which transforms a PC clone into a highly efficient vector processor capable of cellular automata simulation of single fluid flow through two-dimensional rock matrix models of varying porosities. Macroscopic flow patterns have been established through spatial and temporal averaging with no floating point operations. Permeabilities of the different models have been calculated. Hardware allows the algorithm to function on dual processors on a PC platform using a video recording and editing facility. Very encouraging results have been obtained. 4 figs.
Linear Rayleigh-Taylor instability in an accelerated Newtonian fluid with finite width
Piriz, S. A.; Piriz, A. R.; Tahir, N. A.
2018-04-01
The linear theory of Rayleigh-Taylor instability is developed for the case of a viscous fluid layer accelerated by a semi-infinite viscous fluid, considering that the top interface is a free surface. Effects of the surface tensions at both interfaces are taken into account. When viscous effects dominate on surface tensions, an interplay of two mechanisms determines opposite behaviors of the instability growth rate with the thickness of the heavy layer for an Atwood number AT=1 and for sufficiently small values of AT. In the former case, viscosity is a less effective stabilizing mechanism for the thinnest layers. However, the finite thickness of the heavy layer enhances its viscous effects that, in general, prevail on the viscous effects of the semi-infinite medium.
Thermal-Induced Non-linearity of Ag Nano-fluid Prepared using γ-Radiation Method
International Nuclear Information System (INIS)
Esmaeil Shahriari; Wan Mahmood Mat Yunus; Zainal Abidin Talib; Elias Saion
2011-01-01
The non-linear refractive index of Ag nano-fluids prepared by γ-radiation method was investigated using a single beam z-scan technique. Under CW 532 nm laser excitation with power output of 40 mW, the Ag nano-fluids showed a large thermal-induced non-linear refractive index. In the present work it was determined that the non-linear refractive index for Ag nano-fluids is -4.80x10 -8 cm 2 / W. The value of Δn 0 was calculated to be -2.05x10 -4 . Our measurements also confirmed that the non-linear phenomenon was caused by the self-defocusing process making them good candidates for non linear optical devices. (author)
Sankararaman, Sumithra; Menon, Gautam I; Sunil Kumar, P B
2002-09-01
We study the linearized hydrodynamics of a two-component fluid membrane near a repulsive wall, using a model that incorporates curvature-concentration coupling as well as hydrodynamic interactions. This model is a simplified version of a recently proposed one [J.-B. Manneville et al., Phys. Rev. E 64, 021908 (2001)] for nonequilibrium force centers embedded in fluid membranes, such as light-activated bacteriorhodopsin pumps incorporated in phospholipid egg phosphatidyl choline (EPC) bilayers. The pump-membrane system is modeled as an impermeable, two-component bilayer fluid membrane in the presence of an ambient solvent, in which one component, representing active pumps, is described in terms of force dipoles displaced with respect to the bilayer midpoint. We first discuss the case in which such pumps are rendered inactive, computing the mode structure in the bulk as well as the modification of hydrodynamic properties by the presence of a nearby wall. These results should apply, more generally, to equilibrium fluid membranes comprised of two components, in which the effects of curvature-concentration coupling are significant, above the threshold for phase separation. We then discuss the fluctuations and mode structure in the steady state of active two-component membranes near a repulsive wall. We find that proximity to the wall smoothens membrane height fluctuations in the stable regime, resulting in a logarithmic scaling of the roughness even for initially tensionless membranes. This explicitly nonequilibrium result is a consequence of the incorporation of curvature-concentration coupling in our hydrodynamic treatment. This result also indicates that earlier scaling arguments which obtained an increase in the roughness of active membranes near repulsive walls upon neglecting the role played by such couplings may need to be reevaluated.
International Nuclear Information System (INIS)
Sotnikov, V.I.; Paraschiv, I.; Makhin, V.; Bauer, B.S.; Leboeuf, J.N.; Dawson, J.M.
2002-01-01
A systematic study of the linear stage of sheared flow stabilization of Z-pinch plasmas based on the Hall fluid model with equilibrium that contains sheared flow and an axial magnetic field is presented. In the study we begin with the derivation of a general set of equations that permits the evaluation of the combined effect of sheared flow and axial magnetic field on the development of the azimuthal mode number m=0 sausage and m=1 kink magnetohydrodynamic (MHD) instabilities, with the Hall term included in the model. The incorporation of sheared flow, axial magnetic field, and the Hall term allows the Z-pinch system to be taken away from the region in parameter space where ideal MHD is applicable to a regime where nonideal effects tend to govern stability. The problem is then treated numerically by following the linear development in time of an initial perturbation. The numerical results for linear growth rates as a function of axial sheared flow, an axial magnetic field, and the Hall term are reported
Analytical approach to linear fractional partial differential equations arising in fluid mechanics
International Nuclear Information System (INIS)
Momani, Shaher; Odibat, Zaid
2006-01-01
In this Letter, we implement relatively new analytical techniques, the variational iteration method and the Adomian decomposition method, for solving linear fractional partial differential equations arising in fluid mechanics. The fractional derivatives are described in the Caputo sense. The two methods in applied mathematics can be used as alternative methods for obtaining analytic and approximate solutions for different types of fractional differential equations. In these methods, the solution takes the form of a convergent series with easily computable components. The corresponding solutions of the integer order equations are found to follow as special cases of those of fractional order equations. Some numerical examples are presented to illustrate the efficiency and reliability of the two methods
Free piston inertia compressor
Richards, W.D.C.; Bilodeau, D.; Marusak, T.; Dutram, L. Jr.; Brady, J.
A free piston inertia compressor comprises a piston assembly including a connecting rod having pistons on both ends, the cylinder being split into two substantially identical portions by a seal through which the connecting rod passes. Vents in the cylinder wall are provided near the seal to permit gas to escape the cylinder until the piston covers the vent whereupon the remaining gas in the cylinder functions as a gas spring and cushions the piston against impact on the seal. The connecting rod has a central portion of relatively small diameter providing free play of the connecting rod through the seal and end portions of relatively large diameter providing a limited tolerance between the connecting rod and the seal. Finally, the seal comprises a seal ring assembly consisting of a dampener plate, a free floating seal at the center of the dampener plate and a seal retainer plate in one face of the dampener plate.
International Nuclear Information System (INIS)
Kan, K.K.
1983-01-01
The relationship of nuclear internal flow and collective inertia, the difference of this flow from that of a classical fluid, and the approach of this flow to rigid flow in independent-particle model rotation are elucidated by reviewing the theory of Schroedinger fluid and its implications for collective vibration and rotation. (author)
Optimized parallel convolutions for non-linear fluid models of tokamak ηi turbulence
International Nuclear Information System (INIS)
Milovich, J.L.; Tomaschke, G.; Kerbel, G.D.
1993-01-01
Non-linear computational fluid models of plasma turbulence based on spectral methods typically spend a large fraction of the total computing time evaluating convolutions. Usually these convolutions arise from an explicit or semi implicit treatment of the convective non-linearities in the problem. Often the principal convective velocity is perpendicular to magnetic field lines allowing a reduction of the convolution to two dimensions in an appropriate geometry, but beyond this, different models vary widely in the particulars of which mode amplitudes are selectively evolved to get the most efficient representation of the turbulence. As the number of modes in the problem, N, increases, the amount of computation required for this part of the evolution algorithm then scales as N 2 /timestep for a direct or analytic method and N ln N/timestep for a pseudospectral method. The constants of proportionality depend on the particulars of mode selection and determine the size problem for which the method will perform equally. For large enough N, the pseudospectral method performance is always superior, though some problems do not require correspondingly high resolution. Further, the Courant condition for numerical stability requires that the timestep size must decrease proportionately as N increases, thus accentuating the need to have fast methods for larger N problems. The authors have developed a package for the Cray system which performs these convolutions for a rather arbitrary mode selection scheme using either method. The package is highly optimized using a combination of macro and microtasking techniques, as well as vectorization and in some cases assembly coded routines. Parts of the package have also been developed and optimized for the CM200 and CM5 system. Performance comparisons with respect to problem size, parallelization, selection schemes and architecture are presented
Directory of Open Access Journals (Sweden)
Kalidas Das
2018-03-01
Full Text Available The temperament of stream characteristic, heat and mass transfer of MHD forced convective flow over a linearly expanding porous medium has been scrutinized in the progress exploration. The germane possessions of the liquid like viscosity along with thermal conductivity are believed to be variable in nature, directly influenced by the temperature of flow. As soon as gaining the system of leading equations of the stream, Lie symmetric group transformations have been employed to come across the fitting parallel conversions to alter the central PDEs into a suit of ODEs. The renovated system of ODE with appropriate boundary conditions is numerically solved with the assistance of illustrative software MAPLE 17. The consequences of the relevant factors of the system have been exemplified through charts and graphs. An analogous qualified survey has been prepared among present inquiry and subsisting reads and achieved an admirable accord between them. The variable viscosity parameter has more significant effect on nanofluid velocity than regular fluid and temporal profile as well as nanoparticle concentration is also influenced with variable viscosity. Keywords: Nanofluid, Stretching sheet, Variable viscosity, Variable thermal conductivity, Lie symmetry group
Role of size on the relative importance of fluid dynamic losses in linear cryocoolers
Kirkconnell, Carl; Ghavami, Ali; Ghiaasiaan, S. Mostafa; Perrella, Matthew
2017-12-01
Thermodynamic modeling results for a novel small satellite (SmallSat) Stirling Cryocooler, capable of delivering over 200 mW net cooling power at 80 K for less than 6 W DC input power, are used in this paper as the basis for related pulse tube computational fluid dynamics (CFD) analysis. Industry and government requirements for SmallSat infrared sensors are driving the development of ever-more miniaturized cryocooler systems. Such cryocoolers must be extremely compact and lightweight, a challenge met by this research team through operating a Stirling cryocooler at a frequency of approximately 300 Hz. The primary advantage of operating at such a high frequency is that the required compression and expansion swept volumes are reduced relative to linear coolers operating at lower frequencies, which evidently reduces the size of the motor mechanisms and the thermodynamic components. In the case of a pulse tube cryocooler, this includes a reduction in diameter of the pulse tube itself. This unfortunately leads to high boundary layer losses, as the presented results demonstrate. Using a Stirling approach with a mechanical moving expander piston eliminates this small pulse tube loss mechanism, but other challenges are introduced, such as maintaining very tight clearance gaps between moving and stationary elements. This paper focuses on CFD modelling results for a highly miniaturized pulse tube cooler.
Inviscid linear stability analysis of two fluid columns of different densities subject to gravity
Prathama, Aditya; Pantano, Carlos
2017-11-01
We investigate the inviscid linear stability of vertical interface between two fluid columns of different densities under the influence of gravity. In this flow arrangement, the two free streams are continuously accelerating, in contrast to the canonical Kelvin-Helmholtz or Rayleigh-Taylor instabilities whose base flows are stationary (or weakly time dependent). In these classical cases, the temporal evolution of the interface can be expressed as Fourier or Laplace solutions in time. This is not possible in our case; instead, we employ the initial value problem method to solve the equations analytically. The results, expressed in terms of the well-known parabolic cylinder function, indicate that the instability grows as the exponential of a quadratic function of time. The analysis shows that in this accelerating Kelvin-Helmholtz configuration, the interface is unconditionally unstable at all wave modes, despite the presence of surface tension. Department of Energy, National Nuclear Security Administration (Award No. DE-NA0002382) and the California Institute of Technology.
Seismic energy dissipation study of linear fluid viscous dampers in steel structure design
Directory of Open Access Journals (Sweden)
A. Ras
2016-09-01
Full Text Available Energy dissipation systems in civil engineering structures are sought when it comes to removing unwanted energy such as earthquake and wind. Among these systems, there is combination of structural steel frames with passive energy dissipation provided by Fluid Viscous Dampers (FVD. This device is increasingly used to provide better seismic protection for existing as well as new buildings and bridges. A 3D numerical investigation is done considering the seismic response of a twelve-storey steel building moment frame with diagonal FVD that have linear force versus velocity behaviour. Nonlinear time history, which is being calculated by Fast nonlinear analysis (FNA, of Boumerdes earthquake (Algeria, May 2003 is considered for the analysis and carried out using the SAP2000 software and comparisons between unbraced, braced and damped structure are shown in a tabulated and graphical format. The results of the various systems are studied to compare the structural response with and without this device of the energy dissipation thus obtained. The conclusions showed the formidable potential of the FVD to improve the dissipative capacities of the structure without increasing its rigidity. It is contributing significantly to reduce the quantity of steel necessary for its general stability.
DEFF Research Database (Denmark)
Larsen, Jon Steffen; Santos, Ilmar
2015-01-01
An efficient finite element scheme for solving the non-linear Reynolds equation for compressible fluid coupled to compliant structures is presented. The method is general and fast and can be used in the analysis of airfoil bearings with simplified or complex foil structure models. To illustrate...
Orientational dynamics of a triaxial ellipsoid in simple shear flow: Influence of inertia.
Rosén, Tomas; Kotsubo, Yusuke; Aidun, Cyrus K; Do-Quang, Minh; Lundell, Fredrik
2017-07-01
The motion of a single ellipsoidal particle in simple shear flow can provide valuable insights toward understanding suspension flows with nonspherical particles. Previously, extensive studies have been performed on the ellipsoidal particle with rotational symmetry, a so-called spheroid. The nearly prolate ellipsoid (one major and two minor axes of almost equal size) is known to perform quasiperiodic or even chaotic orbits in the absence of inertia. With small particle inertia, the particle is also known to drift toward this irregular motion. However, it is not previously understood what effects from fluid inertia could be, which is of highest importance for particles close to neutral buoyancy. Here, we find that fluid inertia is acting strongly to suppress the chaotic motion and only very weak fluid inertia is sufficient to stabilize a rotation around the middle axis. The mechanism responsible for this transition is believed to be centrifugal forces acting on fluid, which is dragged along with the rotational motion of the particle. With moderate fluid inertia, it is found that nearly prolate triaxial particles behave similarly to the perfectly spheroidal particles. Finally, we also are able to provide predictions about the stable rotational states for the general triaxial ellipsoid in simple shear with weak inertia.
Therapeutic Inertia and Treatment Intensification.
Josiah Willock, Robina; Miller, Joseph B; Mohyi, Michelle; Abuzaanona, Ahmed; Muminovic, Meri; Levy, Phillip D
2018-01-29
This review aims to emphasize how therapeutic inertia, the failure of clinicians to intensify treatment when blood pressure rises or remains above therapeutic goals, contributes to suboptimal blood pressure control in hypertensive populations. Studies reveal that the therapeutic inertia is quite common and contributes to suboptimal blood pressure control. Quality improvement programs and standardized approaches to support antihypertensive treatment intensification are ways to combat therapeutic inertia. Furthermore, programs that utilize non-physician medical professionals such as pharmacists and nurses demonstrate promise in mitigating the effects of this important problem. Therapeutic inertia impedes antihypertensive management and requires a broad effort to reduce its effects. There is an ongoing need for renewed focus and research in this area to improve hypertension control.
Collective inertia in paired systems
International Nuclear Information System (INIS)
Arve, P.O.; Bertsch, G.F.; Michigan State Univ., East Lansing
1988-01-01
Two definitions of the collective inertia are examined. One of them was recently proposed and applied in a calculation of exotic radioactivity. The other expression is the Inglis cranking formula. It is shown that the new formula corresponds to rapid collective motion while the cranking corresponds to slow collective motion. It is also seen that the two forms of the inertia differ only in the choice of the collective momentum. (orig.)
Thermal Inertia of Rocks and Rock Populations
Golombek, M. P.; Jakosky, B. M.; Mellon, M. T.
2001-01-01
The effective thermal inertia of rock populations on Mars and Earth is derived from a model of effective inertia versus rock diameter. Results allow a parameterization of the effective rock inertia versus rock abundance and bulk and fine component inertia. Additional information is contained in the original extended abstract.
DEFF Research Database (Denmark)
Andersen, Michael; Abel, Sarah Maria Niebe; Erleben, Kenny
2017-01-01
We address the task of computing solutions for a separating fluid-solid wall boundary condition model. We present an embarrassingly parallel, easy to implement, fluid LCP solver.We are able to use greater domain sizes than previous works have shown, due to our new solver. The solver exploits matr...
International Nuclear Information System (INIS)
Zubarev, N.M.; Zubareva, O.V.
2017-01-01
The magnetic shaping problem is studied for the situation where a cylindrical column of a perfectly conducting fluid is deformed by the magnetic field of a system of linear current-carrying conductors. Equilibrium is achieved due to the balance of capillary and magnetic pressures. Two two-parametric families of exact solutions of the problem are obtained with the help of conformal mapping technique. In accordance with them, the column essentially deforms in the cross section up to its disintegration.
Zubarev, N. M.; Zubareva, O. V.
2017-06-01
The magnetic shaping problem is studied for the situation where a cylindrical column of a perfectly conducting fluid is deformed by the magnetic field of a system of linear current-carrying conductors. Equilibrium is achieved due to the balance of capillary and magnetic pressures. Two two-parametric families of exact solutions of the problem are obtained with the help of conformal mapping technique. In accordance with them, the column essentially deforms in the cross section up to its disintegration.
Energy Technology Data Exchange (ETDEWEB)
Khan, Masood [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); Hashim, E-mail: hashim_alik@yahoo.com [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); Hussain, M. [Department of Sciences and Humanities, National University of Computer and Emerging Sciences, Islamabad 44000 (Pakistan); Azam, M. [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan)
2016-08-15
This paper presents a study of the magnetohydrodynamic (MHD) boundary layer flow of a non-Newtonian Carreau fluid over a convectively heated surface. The analysis of heat transfer is further performed in the presence of non-linear thermal radiation. The appropriate transformations are employed to bring the governing equations into dimensionless form. The numerical solutions of the partially coupled non-linear ordinary differential equations are obtained by using the Runge-Kutta Fehlberg integration scheme. The influence of non-dimensional governing parameters on the velocity, temperature, local skin friction coefficient and local Nusselt number is studied and discussed with the help of graphs and tables. Results proved that there is significant decrease in the velocity and the corresponding momentum boundary layer thickness with the growth in the magnetic parameter. However, a quite the opposite is true for the temperature and the corresponding thermal boundary layer thickness. - Highlights: • We investigated the Magnetohydrodynamic flow of Carreau constitutive fluid model. • Impact of non-linear thermal radiation is further taken into account. • Runge-Kutta Fehlberg method is employed to obtain the numerical solutions. • Fluid velocity is higher in case of hydromagnetic flow in comparison with hydrodynamic flow. • The local Nusselt number is a decreasing function of the thermal radiation parameter.
Directory of Open Access Journals (Sweden)
K. Ganesh Kumar
Full Text Available A mathematical analysis of two-phase boundary layer flow and heat transfer of a Williamson fluid with fluid particle suspension over a stretching sheet has been carried out in this paper. The region of temperature jump and nonlinear thermal radiation is considered in the energy transfer process. The principal equations of boundary layer flow and temperature transmission are reformed to a set of non-linear ordinary differential equations under suitable similarity transformations. The transfigured equalities are solved numerically with the help of RKF-45 order method. The effect of influencing parameters on velocity and temperature transfer of fluid is examined and deliberated by plotted graphs and tabulated values. Significances of the mass concentration of dust particle parameter play a key role in controlling flow and thermal behavior of non-Newtonian fluids. Further, the temperature and concern boundary layer girth are declines for increasing values of Williamson parameter. Keywords: Two-phase flow, Williamson fluid, Nonlinear thermal radiation, Magnetic field, Temperature jump
Graphical analysis of electron inertia induced acoustic instability
International Nuclear Information System (INIS)
Karmakar, P.K.; Deka, U.; Dwivedi, C.B.
2005-01-01
Recently, the practical significance of the asymptotic limit of m e /m i →0 for electron density distribution has been judged in a two-component plasma system with drifting ions. It is reported that in the presence of drifting ions with drift speed exceeding the ion acoustic wave speed, the electron inertial delay effect facilitates the resonance coupling of the usual fluid ion acoustic mode with the ion-beam mode. In this contribution the same instability is analyzed by graphical and numerical methods. This is to note that the obtained dispersion relation differs from those of the other known normal modes of low frequency ion plasma oscillations and waves. This is due to consideration of electron inertial delay in derivation of the dispersion relation of the ion acoustic wave fluctuations. Numerical calculations of the dispersion relation and wave energy are carried out to depict the graphical appearance of poles and positive-negative energy modes. It is found that the electron inertia induced ion acoustic wave instability arises out of linear resonance coupling between the negative and positive energy modes. Characterization of the resonance nature of the instability in Mach number space for different wave numbers of the ion acoustic mode is presented
Neutron star moments of inertia
Ravenhall, D. G.; Pethick, C. J.
1994-01-01
An approximation for the moment of inertia of a neutron star in terms of only its mass and radius is presented, and insight into it is obtained by examining the behavior of the relativistic structural equations. The approximation is accurate to approximately 10% for a variety of nuclear equations of state, for all except very low mass stars. It is combined with information about the neutron-star crust to obtain a simple expression (again in terms only of mass and radius) for the fractional moment of inertia of the crust.
From resistance to relational inertia
DEFF Research Database (Denmark)
Scheuer, John Damm
-network-theory as a point of departure a new concept – relational inertia – is developed. In this view change agents are theorized as translators who interacts with humans as well as non-humans (objects) in order to construct different types of socio-technical systems which are constructed to perform certain “wished...... inertia that had to be handled in order to succeed with constructing a performative socio-technical risk-management system in practice. Finally it is discussed how this view supplements the resistance to change view and other views with a focus on barriers to change....
Vlasov Fluid stability of a 2-D plasma with a linear magnetic field null
International Nuclear Information System (INIS)
Kim, J.S.
1984-01-01
Vlasov Fluid stability of a 2-dimensional plasma near an O type magnetic null is investigated. Specifically, an elongated Z-pinch is considered, and applied to Field Reversed Configurations at Los Alamos National Laboratory by making a cylindrical approximation of the compact torus. The orbits near an elliptical O type null are found to be very complicated; the orbits are large and some are stochastic. The kinetic corrections to magnetohydrodynamics (MHD) are investigated by evaluating the expectation values of the growth rates of a Vlasov Fluid dispersion functional by using a set of trial functions based on ideal MHD. The dispersion functional involves fluid parts and orbit dependent parts. The latter involves phase integral of two time correlations. The phase integral is replaced by the time integral both for the regular and for the stochastic orbits. Two trial functions are used; one has a large displacement near the null and the other away from the null
Moment of inertia of liquid in a tank
Directory of Open Access Journals (Sweden)
Gyeong Joong Lee
2014-03-01
Full Text Available In this study, the inertial properties of fully filled liquid in a tank were studied based on the potential theory. The analytic solution was obtained for the rectangular tank, and the numerical solutions using Green's 2nd identity were obtained for other shapes. The inertia of liquid behaves like solid in recti-linear acceleration. But under rotational acceleration, the moment of inertia of liquid becomes small compared to that of solid. The shapes of tank investigated in this study were ellipse, rectangle, hexagon, and octagon with various aspect ratios. The numerical solutions were compared with analytic solution, and an ad hoc semi-analytical approximate formula is proposed herein and this formula gives very good predictions for the moment of inertia of the liquid in a tank of several different geometrical shapes. The results of this study will be useful in analyzing of the motion of LNG/LPG tanker, liquid cargo ship, and damaged ship.
Improving total-building seismic performance using linear fluid viscous dampers
Del Gobbo, GM; Blakeborough, A; Williams, MS
2018-01-01
Previous research has revealed that Eurocode-compliant structures can experience structural and nonstructural damage during earthquakes. Retrofitting buildings with fluid viscous dampers (FVDs) can improve interstorey drifts and floor accelerations, two structural parameters that characterize seismic demand. Previous research focusing on FVD applications for improving seismic performance has focused on structural performance. Structural parameters such as interstorey drifts and floor accelera...
On the linear problem arising from motion of a fluid around a moving rigid body
Czech Academy of Sciences Publication Activity Database
Nečasová, Šárka; Wolf, J.
2015-01-01
Roč. 140, č. 2 (2015), s. 241-259 ISSN 0862-7959 R&D Projects: GA ČR(CZ) GAP201/11/1304 Institutional support: RVO:67985840 Keywords : incompressible fluid * rotating rigid body * strong solution Subject RIV: BA - General Mathematics http://hdl.handle.net/10338.dmlcz/144329
International Nuclear Information System (INIS)
Archambeau, C.B.
1994-01-01
A fractured solid under stress loading (or unloading) can be viewed as behaving macroscopically as a medium with internal, hidden, degrees of freedom, wherein changes in fracture geometry (i.e. opening, closing and extension) and flow of fluid and gas within fractures will produce major changes in stresses and strains within the solid. Likewise, the flow process within fractures will be strongly coupled to deformation within the solid through boundary conditions on the fracture surfaces. The effects in the solid can, in part, be phenomenologically represented as inelastic or plastic processes in the macroscopic view. However, there are clearly phenomena associated with fracture growth and open fracture fluid flows that produce effects that can not be described using ordinary inelastic phenomenology. This is evident from the fact that a variety of energy release phenomena can occur, including seismic emissions of previously stored strain energy due to fracture growth, release of disolved gas from fluids in the fractures resulting in enhanced buoyancy and subsequent energetic flows of gas and fluids through the fracture system which can produce raid extension of old fractures and the creation of new ones. Additionally, the flows will be modulated by the opening and closing of fractures due to deformation in the solid, so that the flow process is strongly coupled to dynamical processes in the surrounding solid matrix, some of which are induced by the flow itself
Noise analysis of fluid-valve system in a linear compressor using CAE
International Nuclear Information System (INIS)
Lee, Jun Ho; Jeong, Weui Bong; Kim, Dang Ju
2009-01-01
A linear compressor in a refrigerator uses piston motion to transfer refrigerant so its efficiency is higher than a previous reciprocal compressor. Because of interaction between refrigerant and valves system in the linear compressor, however, noise has been a main issue. In spite of doing many experimental researches, there is no way to rightly predict the noise. In order to solve this limitation, the CAE analysis is applied. For giving credit to these computational data, all of the data are experimentally validated.
A symbiotic approach to fluid equations and non-linear flux-driven simulations of plasma dynamics
Halpern, Federico
2017-10-01
The fluid framework is ubiquitous in studies of plasma transport and stability. Typical forms of the fluid equations are motivated by analytical work dating several decades ago, before computer simulations were indispensable, and can be, therefore, not optimal for numerical computation. We demonstrate a new first-principles approach to obtaining manifestly consistent, skew-symmetric fluid models, ensuring internal consistency and conservation properties even in discrete form. Mass, kinetic, and internal energy become quadratic (and always positive) invariants of the system. The model lends itself to a robust, straightforward discretization scheme with inherent non-linear stability. A simpler, drift-ordered form of the equations is obtained, and first results of their numerical implementation as a binary framework for bulk-fluid global plasma simulations are demonstrated. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, Theory Program, under Award No. DE-FG02-95ER54309.
Physician and patient characteristics associated with clinical inertia in blood pressure control.
Harle, Christopher A; Harman, Jeffrey S; Yang, Shuo
2013-11-01
Clinical inertia, the failure to adjust antihypertensive medications during patient visits with uncontrolled hypertension, is thought to be a common problem. This retrospective study used 5 years of electronic medical records from a multispecialty group practice to examine the association between physician and patient characteristics and clinical inertia. Hierarchical linear models (HLMs) were used to examine (1) differences in physician and patient characteristics among patients with and without clinical inertia, and (2) the association between clinical inertia and future uncontrolled hypertension. Overall, 66% of patients experienced clinical inertia. Clinical inertia was associated with one physician characteristic, patient volume (odds ratio [OR]=0.998). However, clinical inertia was associated with multiple patient characteristics, including patient age (OR=1.021), commercial insurance (OR=0.804), and obesity (OR=1.805). Finally, patients with clinical inertia had 2.9 times the odds of uncontrolled hypertension at their final visit in the study period. These findings may aid the design of interventions to reduce clinical inertia. ©2013 Wiley Periodicals, Inc.
Moment of Inertia by Differentiation
Rizcallah, Joseph A.
2015-01-01
The calculation of the moment of inertia of an extended body, as presented in standard introductory-level textbooks, involves the evaluation of a definite integral--an operation often not fully mastered by beginners, let alone the conceptual difficulties it presents, even to the advanced student, in understanding and setting up the integral in the…
International Nuclear Information System (INIS)
Navarro, J. A.; Madariaga, J. A.; Santamaria, C. M.; Saviron, J. M.
1980-01-01
10 refs. Flow pattern calculations in natural convection between two vertical coaxial cylinders are reported. It is assumed trough the paper. that fluid properties, viscosity, thermal conductivity and density, depend no-linearly on temperature and that the aspects (height/radius) ratio of the cylinders is high. Velocity profiles are calculated trough a perturbative scheme and analytic results for the three first perturbation orders are presented. We outline also an iterative method to estimate the perturbations on the flow patterns which arise when a radial composition gradient is established by external forces in a two-component fluid. This procedure, based on semiempirical basis, is applied to gaseous convection. The influence of the molecules gas properties on tho flow is also discussed. (Author) 10 refs
Londono, J.M.; Wagg, D.; Neild, S.A.
2014-01-01
Viscous fluid dampers have proved to be effective in suppressing unwanted vibrations in a range of engineering structures. When dampers are fitted in a structure, a brace is typically used to attach them to the main structure. The stiffness of this brace can significantly alter the effectiveness of the damper, and in structures with multiple dampers, this can be a complex scenario to model. In this paper, we demonstrate that the effects of the brace compliance on the damper performance can be...
Directory of Open Access Journals (Sweden)
Yan Zhang
2011-01-01
Full Text Available The problem of steady, laminar, thermal Marangoni convection flow of non-Newtonian power law fluid along a horizontal surface with variable surface temperature is studied. The partial differential equations are transformed into ordinary differential equations by using a suitable similarity transformation and analytical approximate solutions are obtained by an efficient transformation, asymptotic expansion and Padé approximants technique. The effects of power law index and Marangoni number on velocity and temperature profiles are examined and discussed.
A class of parallel algorithms for computation of the manipulator inertia matrix
Fijany, Amir; Bejczy, Antal K.
1989-01-01
Parallel and parallel/pipeline algorithms for computation of the manipulator inertia matrix are presented. An algorithm based on composite rigid-body spatial inertia method, which provides better features for parallelization, is used for the computation of the inertia matrix. Two parallel algorithms are developed which achieve the time lower bound in computation. Also described is the mapping of these algorithms with topological variation on a two-dimensional processor array, with nearest-neighbor connection, and with cardinality variation on a linear processor array. An efficient parallel/pipeline algorithm for the linear array was also developed, but at significantly higher efficiency.
Mustafa, M.; Mushtaq, A.; Hayat, T.; Alsaedi, A.
2018-04-01
Mathematical model for Maxwell fluid flow in rotating frame induced by an isothermal stretching wall is explored numerically. Scale analysis based boundary layer approximations are applied to simplify the conservation relations which are later converted to similar forms via appropriate substitutions. A numerical approach is utilized to derive similarity solutions for broad range of Deborah number. The results predict that velocity distributions are inversely proportional to the stress relaxation time. This outcome is different from that observed for the elastic parameter of second grade fluid. Unlike non-rotating frame, the solution curves are oscillatory decaying functions of similarity variable. As angular velocity enlarges, temperature rises and significant drop in the heat transfer coefficient occurs. We note that the wall slope of temperature has an asymptotically decaying profile against the wall to ambient ratio parameter. From the qualitative view point, temperature ratio parameter and radiation parameter have similar effect on the thermal boundary layer. Furthermore, radiation parameter has a definite role in improving the cooling process of the stretching boundary. A comparative study of current numerical computations and those from the existing studies is also presented in a limiting case. To our knowledge, the phenomenon of non-linear radiation in rotating viscoelastic flow due to linearly stretched plate is just modeled here.
Phylogenetic inertia and Darwin's higher law.
Shanahan, Timothy
2011-03-01
The concept of 'phylogenetic inertia' is routinely deployed in evolutionary biology as an alternative to natural selection for explaining the persistence of characteristics that appear sub-optimal from an adaptationist perspective. However, in many of these contexts the precise meaning of 'phylogenetic inertia' and its relationship to selection are far from clear. After tracing the history of the concept of 'inertia' in evolutionary biology, I argue that treating phylogenetic inertia and natural selection as alternative explanations is mistaken because phylogenetic inertia is, from a Darwinian point of view, simply an expected effect of selection. Although Darwin did not discuss 'phylogenetic inertia,' he did assert the explanatory priority of selection over descent. An analysis of 'phylogenetic inertia' provides a perspective from which to assess Darwin's view. Copyright © 2010 Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Culetu, H.
1990-09-01
A dynamical origin to the Minkowski geometry is suggested in this paper. The Minkowski internal (-x α x α ) 1/2 plays the role of the fifth dimension. We found the energy-momentum vector p μ (associated to a ''motion in scale'') of a ''free'' relativistic particle in position-dependent. When x i and ''t'' are not independent, we are naturally led to the law of inertia. (author). 10 refs
International Nuclear Information System (INIS)
Nielsen, Tim; Brendel, Bernhard; Ziegler, Ronny; Beek, Michiel van; Uhlemann, Falk; Bontus, Claas; Koehler, Thomas
2009-01-01
Diffuse optical tomography (DOT) is a potential new imaging modality to detect or monitor breast lesions. Recently, Philips developed a new DOT system capable of transmission and fluorescence imaging, where the investigated breast is hanging freely into the measurement cup containing scattering fluid. We present a fast and robust image reconstruction algorithm that is used for the transmission measurements. The algorithm is based on the Rytov approximation. We show that this algorithm can be used over a wide range of tissue optical properties if the reconstruction is adapted to each patient. We use estimates of the breast shape and average tissue optical properties to initialize the reconstruction, which improves the image quality significantly. We demonstrate the capability of the measurement system and reconstruction to image breast lesions by clinical examples
Directory of Open Access Journals (Sweden)
V. Génot
2009-02-01
Full Text Available Using 5 years of Cluster data, we present a detailed statistical analysis of magnetic fluctuations associated with mirror structures in the magnetosheath. We especially focus on the shape of these fluctuations which, in addition to quasi-sinusoidal forms, also display deep holes and high peaks. The occurrence frequency and the most probable location of the various types of structures is discussed, together with their relation to local plasma parameters. While these properties have previously been correlated to the β of the plasma, we emphasize here the influence of the distance to the linear mirror instability threshold. This enables us to interpret the observations of mirror structures in a stable plasma in terms of bistability and subcritical bifurcation. The data analysis is supplemented by the prediction of a quasi-static anisotropic MHD model and hybrid numerical simulations in an expanding box aimed at mimicking the magnetosheath plasma. This leads us to suggest a scenario for the formation and evolution of mirror structures.
An inertia-free filter line-search algorithm for large-scale nonlinear programming
Energy Technology Data Exchange (ETDEWEB)
Chiang, Nai-Yuan; Zavala, Victor M.
2016-02-15
We present a filter line-search algorithm that does not require inertia information of the linear system. This feature enables the use of a wide range of linear algebra strategies and libraries, which is essential to tackle large-scale problems on modern computing architectures. The proposed approach performs curvature tests along the search step to detect negative curvature and to trigger convexification. We prove that the approach is globally convergent and we implement the approach within a parallel interior-point framework to solve large-scale and highly nonlinear problems. Our numerical tests demonstrate that the inertia-free approach is as efficient as inertia detection via symmetric indefinite factorizations. We also demonstrate that the inertia-free approach can lead to reductions in solution time because it reduces the amount of convexification needed.
Primary uterine inertia in four labrador bitches.
Davidson, Autumn P
2011-01-01
Uterine inertia is a common cause of dystocia in the bitch and is designated as primary (i.e., uterine contractions fail to ever be initiated) or secondary (i.e., uterine contractions cease after a period of time but before labor is completed). The etiology of primary uterine inertia is not well understood. The accurate diagnosis of primary uterine inertia requires the use of tocodynamometry (uterine monitoring). Primary uterine inertia has been postulated to result from a failure of luteolysis resulting in persistently elevated progesterone concentrations. In this study, primary uterine inertia was diagnosed in a series of four bitches in which luteolysis was documented suggesting some other etiopathogenesis for primary uterine inertia.
WAYS TO MANAGE HEATING INERTIA
Directory of Open Access Journals (Sweden)
E. V. Biloshytskyi
2017-08-01
Full Text Available Purpose. The research paper proposes to estimate the effect of heat inertia of the water heating system, in transient operation modes, on the temperature condition in the passenger car, as well as to offer technical solutions intended to reduce the heating system inertia effect and to maintain a stable temperature condition in the passenger car premises in transitional modes of the heating system. Methodology. The author developed the method for controlling the heat transfer of heating system pipes with the help of regulating casing. To control the heating system and the heat transfer of heating pipes, two types of temperature control sensors were used in the passenger car: certain sensors interacted with regulatory casings, while the others interacted with high-voltage tubular heating element control devices. To assess the efficiency of heat interchange regulation of heating pipes and the heating system control, with installed regulating casings, the operation of the heating system with regulating casings and two types of sensors was mathematically modelled. Mathematical modelling used the experimental test data. The results of experimental tests and mathematical modelling were compared. Findings. Currently in operated passenger cars, control of heating appliances is not constructively provided. Automatic maintenance of the set temperature in a passenger car is limited to switching on and off of high-voltage tubular heating elements. The use of regulating casings on heating pipes allows reducing the effects of heat inertia and maintaining stable thermal conditions in a passenger car, using the heating system as a heat accumulator, and also provides the opportunity to realize an individual control of air temperature in the compartment. Originality. For the first time, the paper studied the alternative ways of regulating the temperature condition in a passenger car. Using of the heating system as a heat accumulator. Practical value. The
Effects of electron inertia in collisionless magnetic reconnection
Energy Technology Data Exchange (ETDEWEB)
Andrés, Nahuel, E-mail: nandres@iafe.uba.ar; Gómez, Daniel [Instituto de Astronomía y Física del Espacio, CC. 67, suc. 28, 1428, Buenos Aires (Argentina); Departamento de Física, Facultad de Ciencias Exactas y Naturales, Univrsidad de Buenos Aires, Pabellón I, 1428, Buenos Aires (Argentina); Martin, Luis; Dmitruk, Pablo [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Univrsidad de Buenos Aires, Pabellón I, 1428, Buenos Aires (Argentina)
2014-07-15
We present a study of collisionless magnetic reconnection within the framework of full two-fluid MHD for a completely ionized hydrogen plasma, retaining the effects of the Hall current, electron pressure and electron inertia. We performed 2.5D simulations using a pseudo-spectral code with no dissipative effects. We check that the ideal invariants of the problem are conserved down to round-off errors. Our numerical results confirm that the change in the topology of the magnetic field lines is exclusively due to the presence of electron inertia. The computed reconnection rates remain a fair fraction of the Alfvén velocity, which therefore qualifies as fast reconnection.
Effects of additional inertia force on bubble breakup
International Nuclear Information System (INIS)
Pan Liangming; Zhang Wenzhi; Chen Deqi; Xu Jianhui; Xu Jianjun; Huang Yanping
2011-01-01
Through VOF two-phase flow model, the single bubble deformation and breakup in a vertical narrow channel is numerically investigated in the study based on the force balance at the process of bubble breakup. The effect of surface tension force, the additional inertia force and bubble initial shape on bubble breakup are analyzed according to the velocity variation at the break-up point and the minimum necking size when the bubble is breaking up. It is found that the surface tension force, the additional inertia force and the bubble initial shape have significant effects on the bubble breakup through the fluid injection toward to the bubble, which finally induces the onset of bubble breakup. (authors)
Gross shell structure of moments of inertia
International Nuclear Information System (INIS)
Deleplanque, M.A.; Frauendorf, S.; Pashkevich, V.V.; Chu, S.Y.; Unzhakova, A.
2002-01-01
Average yrast moments of inertia at high spins, where the pairing correlations are expected to be largely absent, were found to deviate from the rigid-body values. This indicates that shell effects contribute to the moment of inertia. We discuss the gross dependence of moments of inertia and shell energies on the neutron number in terms of the semiclassical periodic orbit theory. We show that the ground-state shell energies, nuclear deformations and deviations from rigid-body moments of inertia are all due to the same periodic orbits
Clinical Inertia and Outpatient Medical Errors
National Research Council Canada - National Science Library
O'Connor, Patrick J; Sperl-Hillen, JoAnn M; Johnson, Paul E; Rush, William A; Biltz, George
2005-01-01
.... Clinical inertia is a major factor that contributes to inadequate chronic disease care in patients with diabetes mellitus, hypertension, dyslipidemias, depression, coronary heart disease, and other conditions...
International Nuclear Information System (INIS)
Wilk, R.; Syc, B.; Bajor, G.; Kluczewska, E.
2011-01-01
Currently, a few imaging methods are used in CNS diagnostics: computed tomography - CT, magnetic resonance imaging - MRI, and ultrasonography - USG. The ventricular system changes its dimensions with child's development. Linear indices commonly used in the diagnostics of hydrocephalus do not consider developmental changes of the intracranial fluid spaces. The aim of our work was to identify reference values for selected linear indices in specific age groups. Material/Methods: The material included 507 CT examinations of the head in children of different age and both sexes. There were 381 CT examinations considered as normal and they were used to establish the reference values. They were compared with 126 CTs from the observational zone (3-10 percentile and 90-97 percentile). The children were divided into 7 following age groups: 0-12 months, > 12-36 months, > 3-6 years, > 6-9 years, > 9-12 years, > 12-15 years, > 15-18 years. For every group, the 10 th , 25 th , 50 th , 75 th and 90 th percentile was calculated. The range between the 10 th and the 90 th percentile was described as a norm. Results: Reference values for particular indices: Huckman Number from 3.3 to 5.0 cm with correlation coefficient according to age equal to 0.34; Evans' Index from 0.218 to 0.312 with correlation coefficient of -0.12; Bifrontal Index from 0.265 to 0.380 with correlation coefficient of 0.18; Bicaudate / Frontal Index from 0.212 to 0.524 with correlation coefficient of -0,33; Bicaudate Index from 0.059 to 0.152 with correlation coefficient of -0.26; Bicaudate / Temporal Index from 0.051 to 0.138 with correlation coefficient of 0.32; Schiersmann's Index from 3.545 to 6.038 with correlation coefficient of 0.42. Conclusions: The intracerebral CSF spaces increased in a non-uniform manner with age. All indices established on the basis of linear parameters were relatively higher in younger children than in the older ones. In proportion to the cranial size, the intracranial fluid spaces
Analysis on the influence of the pump start transient performance with different inertia impeller
International Nuclear Information System (INIS)
Tang, Y; Cheng, J; Liu, E H; Tang, L D
2012-01-01
Centrifugal pump start-up time is very short, in the boot process, the instantaneous head and flow will have an impact role to the pipeline, and however the moment of inertia is one of the main factors affecting centrifugal pump boot acceleration. We analyzed the pump start-up transient characteristics with the different moment of inertia of the impeller corresponding to the different materials, there are three different moment of inertia of the impeller have been selected. At first, we use the 'Flowmaster' fluid system simulation software do the outer characteristics simulation to the selected-model, get the time - flow and the time - speed curve. Then, do the experiments research in the process when pump start-up, and compare with the simulation result. At last use the outer characteristics simulation result as the boundary, using the ANASYS CFX software do the transient simulation to the three groups with different inertia pump impeller, and draw the pressure distribution picture. In according to the analysis, we can confirm that the impact of inertia is one of the factors in the stability during the pump star, and we can get that the greater moment of inertia, the longer the boot stable. We also can get that combined Flowmaster with ANSYS can solved engineering practice problem in fluid system conveniently, and take it easy to solve the similar problem.
D-dimensional moments of inertia
International Nuclear Information System (INIS)
Bender, C.M.; Mead, L.R.
1995-01-01
We calculate the moments of inertia of D-dimensional spheres and spherical shells, where D is a complex number. We also examine the moments of inertia of fractional-dimensional geometrical objects such as the Cantor set and the Sierpinski carpet and their D-dimensional analogs. copyright 1995 American Association of Physics Teachers
Dynamical moments of inertia for superdeformed nuclei
International Nuclear Information System (INIS)
Obikhod, T.V.
1995-01-01
The method of quantum groups has been applied for calculation the dynamical moments of inertia for the yrast superdeformed bands in 194 Hg and 192 Hg as well as to calculation of the dynamical moments of inertia of superdeformed bands in 150 Gd and 148 Gd
Directory of Open Access Journals (Sweden)
Patrick Grahn
2018-03-01
Full Text Available A change in momentum will inevitably perturb the all-embracing vacuum, whose reaction we understand as inertia. Since the vacuum’s physical properties relate to light, we propose that the vacuum embodies photons, but in pairs without net electromagnetic fields. In this physical form the free space houses energy in balance with the energy of matter in the whole Universe. Likewise, we reason that a local gravitational potential is the vacuum in a local balance with energy that is bound to a body. Since a body couples to the same vacuum universally and locally, we understand that inertial and gravitational masses are identical. By the same token, we infer that gravity and electromagnetism share the similar functional form because both are carried by the vacuum photons as paired and unpaired.
Directory of Open Access Journals (Sweden)
Lihang Feng
Full Text Available Wheel force transducer (WFT, which measures the three-axis forces and three-axis torques applied to the wheel, is an important instrument in the vehicle testing field and has been extremely promoted by researchers with great interests. The transducer, however, is typically mounted on the wheel of a moving vehicle, especially on a high speed car, when abruptly accelerating or braking, the mass/inertia of the transducer/wheel itself will have an extra effect on the sensor response so that the inertia/mass loads will also be detected and coupled into the signal outputs. The effect which is considered to be inertia coupling problem will decrease the sensor accuracy. In this paper, the inertia coupling of a universal WFT under multi-axis accelerations is investigated. According to the self-decoupling approach of the WFT, inertia load distribution is solved based on the principle of equivalent mass and rotary inertia, thus then inertia impact can be identified with the theoretical derivation. The verification is achieved by FEM simulation and experimental tests. Results show that strains in simulation agree well with the theoretical derivation. The relationship between the applied acceleration and inertia load for both wheel force and moment is the approximate linear, respectively. All the relative errors are less than 5% which are within acceptable and the inertia loads have the maximum impact on the signal output about 1.5% in the measurement range.
Feng, Lihang; Lin, Guoyu; Zhang, Weigong; Dai, Dong
2015-01-01
Wheel force transducer (WFT), which measures the three-axis forces and three-axis torques applied to the wheel, is an important instrument in the vehicle testing field and has been extremely promoted by researchers with great interests. The transducer, however, is typically mounted on the wheel of a moving vehicle, especially on a high speed car, when abruptly accelerating or braking, the mass/inertia of the transducer/wheel itself will have an extra effect on the sensor response so that the inertia/mass loads will also be detected and coupled into the signal outputs. The effect which is considered to be inertia coupling problem will decrease the sensor accuracy. In this paper, the inertia coupling of a universal WFT under multi-axis accelerations is investigated. According to the self-decoupling approach of the WFT, inertia load distribution is solved based on the principle of equivalent mass and rotary inertia, thus then inertia impact can be identified with the theoretical derivation. The verification is achieved by FEM simulation and experimental tests. Results show that strains in simulation agree well with the theoretical derivation. The relationship between the applied acceleration and inertia load for both wheel force and moment is the approximate linear, respectively. All the relative errors are less than 5% which are within acceptable and the inertia loads have the maximum impact on the signal output about 1.5% in the measurement range.
Massive Submucosal Ganglia in Colonic Inertia.
Naemi, Kaveh; Stamos, Michael J; Wu, Mark Li-Cheng
2018-02-01
- Colonic inertia is a debilitating form of primary chronic constipation with unknown etiology and diagnostic criteria, often requiring pancolectomy. We have occasionally observed massively enlarged submucosal ganglia containing at least 20 perikarya, in addition to previously described giant ganglia with greater than 8 perikarya, in cases of colonic inertia. These massively enlarged ganglia have yet to be formally recognized. - To determine whether such "massive submucosal ganglia," defined as ganglia harboring at least 20 perikarya, characterize colonic inertia. - We retrospectively reviewed specimens from colectomies of patients with colonic inertia and compared the prevalence of massive submucosal ganglia occurring in this setting to the prevalence of massive submucosal ganglia occurring in a set of control specimens from patients lacking chronic constipation. - Seven of 8 specimens affected by colonic inertia harbored 1 to 4 massive ganglia, for a total of 11 massive ganglia. One specimen lacked massive ganglia but had limited sampling and nearly massive ganglia. Massive ganglia occupied both superficial and deep submucosal plexus. The patient with 4 massive ganglia also had 1 mitotically active giant ganglion. Only 1 massive ganglion occupied the entire set of 10 specimens from patients lacking chronic constipation. - We performed the first, albeit distinctly small, study of massive submucosal ganglia and showed that massive ganglia may be linked to colonic inertia. Further, larger studies are necessary to determine whether massive ganglia are pathogenetic or secondary phenomena, and whether massive ganglia or mitotically active ganglia distinguish colonic inertia from other types of chronic constipation.
Flapping inertia for selected rotor blades
Berry, John D.; May, Matthew J.
1991-01-01
Aerodynamics of helicopter rotor systems cannot be investigated without consideration for the dynamics of the rotor. One of the principal properties of the rotor which affects the rotor dynamics is the inertia of the rotor blade about its root attachment. Previous aerodynamic investigation have been performed on rotor blades with a variety of planforms to determine the performance differences due to blade planform. The blades tested for this investigation have been tested on the U.S. Army 2 meter rotor test system (2MRTS) in the NASA Langley 14 by 22 foot subsonic tunnel for hover performance. This investigation was intended to provide fundamental information on the flapping inertia of five rotor blades with differing planforms. The inertia of the bare cuff and the cuff with a blade extension were also measured for comparison with the inertia of the blades. Inertia was determined using a swing testing technique, using the period of oscillation to determine the effective flapping inertia. The effect of damping in the swing test was measured and described. A comparison of the flapping inertials for rectangular and tapered planform blades of approximately the same mass showed the tapered blades to have a lower inertia, as expected.
Inertia-dependent dynamics of three-dimensional vesicles and red blood cells in shear flow.
Luo, Zheng Yuan; Wang, Shu Qi; He, Long; Xu, Feng; Bai, Bo Feng
2013-10-28
A three-dimensional (3D) simulation study of the effect of inertia on the dynamics of vesicles and red blood cells (RBCs) has not been reported. Here, we developed a 3D model based on the front tracking method to investigate how inertia affects the dynamics of spherical/non-spherical vesicles and biconcave-shaped RBCs with the Reynolds number ranging from 0.1 to 10. The results showed that inertia induced non-spherical vesicles transitioned from tumbling to swinging, which was not observed in previous 2D models. The critical viscosity ratio of inner/outer fluids for the tumbling–swinging transition remarkably increased with an increasing Reynolds number. The deformation of vesicles was greatly enhanced by inertia, and the frequency of tumbling and tank-treading was significantly decreased by inertia. We also found that RBCs can transit from tumbling to steady tank-treading through the swinging regime when the Reynolds number increased from 0.1 to 10. These results indicate that inertia needs to be considered at moderate Reynolds number (Re ~ 1) in the study of blood flow in the human body and the flow of deformable particle suspension in inertial microfluidic devices. The developed 3D model provided new insights into the dynamics of RBCs under shear flow, thus holding great potential to better understand blood flow behaviors under normal/disease conditions.
Moment of inertia of liquid in a tank
Directory of Open Access Journals (Sweden)
Lee Gyeong Joong
2014-03-01
Full Text Available In this study, the inertial properties of fully filled liquid in a tank were studied based on the potential theory. The analytic solution was obtained for the rectangular tank, and the numerical solutions using Green’s 2nd identity were obtained for other shapes. The inertia of liquid behaves like solid in recti-linear acceleration. But under rotational acceleration, the moment of inertia of liquid becomes small compared to that of solid. The shapes of tank investigated in this study were ellipse, rectangle, hexagon, and octagon with various aspect ratios. The numerical solu¬tions were compared with analytic solution, and an ad hoc semi-analytical approximate formula is proposed herein and this formula gives very good predictions for the moment of inertia of the liquid in a tank of several different geometrical shapes. The results of this study will be useful in analyzing of the motion of LNG/LPG tanker, liquid cargo ship, and damaged ship.
Effect of particle inertia and gravity on the turbulence in a suspension
Ooms, G.; Poesio, P.
2005-01-01
A theoretical model is presented for the effect of particle inertia and gravity on the turbulence in a homogeneous suspension. It is an extension of the one-fluid model developed by L’vov, Ooms, and Pomyalov [Phys. Rev. E 67, 046314 (2003)] , in which the effect of gravity was not considered. In the
Weight, gravitation, inertia, and tides
Pujol, Olivier; Lagoute, Christophe; Pérez, José-Philippe
2015-11-01
This paper deals with the factors that influence the weight of an object near the Earth's surface. They are: (1) the Earth's gravitational force, (2) the centrifugal force due to the Earth's diurnal rotation, and (3) tidal forces due to the gravitational field of the Moon and Sun, and other solar system bodies to a lesser extent. Each of these three contributions is discussed and expressions are derived. The relationship between weight and gravitation is thus established in a direct and pedagogical manner readily understandable by undergraduate students. The analysis applies to the Newtonian limit of gravitation. The derivation is based on an experimental (or operational) definition of weight, and it is shown that it coincides with the Earth’s gravitational force modified by diurnal rotation around a polar axis and non-uniformity of external gravitational bodies (tidal term). Two examples illustrate and quantify these modifications, respectively the Eötvös effect and the oceanic tides; tidal forces due to differential gravitation on a spacecraft and an asteroid are also proposed as examples. Considerations about inertia are also given and some comments are made about a widespread, yet confusing, explanation of tides based on a centrifugal force. Finally, the expression of the potential energy of the tide-generating force is established rigorously in the appendix.
Weight, gravitation, inertia, and tides
International Nuclear Information System (INIS)
Pujol, Olivier; Lagoute, Christophe; Pérez, José-Philippe
2015-01-01
This paper deals with the factors that influence the weight of an object near the Earth's surface. They are: (1) the Earth's gravitational force, (2) the centrifugal force due to the Earth's diurnal rotation, and (3) tidal forces due to the gravitational field of the Moon and Sun, and other solar system bodies to a lesser extent. Each of these three contributions is discussed and expressions are derived. The relationship between weight and gravitation is thus established in a direct and pedagogical manner readily understandable by undergraduate students. The analysis applies to the Newtonian limit of gravitation. The derivation is based on an experimental (or operational) definition of weight, and it is shown that it coincides with the Earth’s gravitational force modified by diurnal rotation around a polar axis and non-uniformity of external gravitational bodies (tidal term). Two examples illustrate and quantify these modifications, respectively the Eötvös effect and the oceanic tides; tidal forces due to differential gravitation on a spacecraft and an asteroid are also proposed as examples. Considerations about inertia are also given and some comments are made about a widespread, yet confusing, explanation of tides based on a centrifugal force. Finally, the expression of the potential energy of the tide-generating force is established rigorously in the appendix. (paper)
Electron-inertia effects on driven magnetic field reconnection
International Nuclear Information System (INIS)
Al-Salti, N.; Shivamoggi, B.K.
2003-01-01
Electron-inertia effects on the magnetic field reconnection induced by perturbing the boundaries of a slab of plasma with a magnetic neutral surface inside are considered. Energetics of the tearing mode dynamics with electron inertia which controls the linearized collisionless magnetohydrodynamics (MHD) are considered with a view to clarify the role of the plasma pressure in this process. Cases with the boundaries perturbed at rates slow or fast compared with the hydromagnetic evolution rate are considered separately. When the boundaries are perturbed at a rate slow compared with the hydromagnetic evolution rate and fast compared with the resistive diffusion rate, the plasma response for early times is according to ideal MHD. A current sheet formation takes place at the magnetic neutral surface for large times in the ideal MHD stage and plasma becomes motionless. The subsequent evolution of the current sheet is found to be divided into two distinct stages: (i) the electron-inertia stage for small times (when the current sheet is very narrow); (ii) the resistive-diffusion stage for large times. The current sheet mainly undergoes exponential damping in the electron-inertia regime while the bulk of the diffusion happens in the resistivity regime. For large times of the resistive-diffusion stage when plasma flow is present, the current sheet completely disappears and the magnetic field reconnection takes place. When the boundaries are perturbed at a rate fast compared even with the hydromagnetic evolution rate, there is no time for the development of a current sheet and the magnetic field reconnection has been found not to take place
Virtual inertia for variable speed wind turbines
DEFF Research Database (Denmark)
Zeni, Lorenzo; Rudolph, Andreas Jakob; Münster-Swendsen, Janus
2013-01-01
electronic converter and on its impact on the primary frequency response of a power system. An additional control for the power electronics is implemented to give VSWTs a virtual inertia, referring to the kinetic energy stored in the rotating masses, which can be released initially to support the system......’s inertia. A simple Matlab/Simulink model and control of a VSWT and of a generic power system are developed to analyse the primary frequency response following different generation losses in a system comprising VSWTs provided with virtual inertia. The possibility of substituting a 50% share of conventional...... power with wind is also assessed and investigated. The intrinsic problems related to the implementation of virtual inertia are illustrated, addressing their origin in the action of pitch and power control. A solution is proposed, which aims at obtaining the same response as for the system with only...
A Reevaluation of the Attentional Inertia Concept
W.J.M.I. Verbeke (Willem)
1992-01-01
textabstractAnderson's (1983) theory about children's attention behavior during television viewing hypothesizes that attention behavior is affected by positive feedback (the inertia hypothesis) and the degree to which a child understands the television program. During an experiment, neither
Moments of inertia in a semiclassical approach
International Nuclear Information System (INIS)
Benchein, K.
1993-01-01
Semiclassical calculations have been performed for 31 nuclei. As a result of preliminary non-fully self-consistent calculations, the moments of inertia in investigated nuclei abd spin degrees of freedom are found
Social inertia and diversity in collaboration networks
Ramasco, J. J.
2007-04-01
Random graphs are useful tools to study social interactions. In particular, the use of weighted random graphs allows to handle a high level of information concerning which agents interact and in which degree the interactions take place. Taking advantage of this representation, we recently defined a magnitude, the Social Inertia, that measures the eagerness of agents to keep ties with previous partners. To study this magnitude, we used collaboration networks that are specially appropriate to obtain valid statitical results due to the large size of publically available databases. In this work, I study the Social Inertia in two of these empirical networks, IMDB movie database and condmat. More specifically, I focus on how the Inertia relates to other properties of the graphs, and show that the Inertia provides information on how the weight of neighboring edges correlates. A social interpretation of this effect is also offered.
Electrohydrodynamics of a viscous drop with inertia.
Nganguia, H; Young, Y-N; Layton, A T; Lai, M-C; Hu, W-F
2016-05-01
Most of the existing numerical and theoretical investigations on the electrohydrodynamics of a viscous drop have focused on the creeping Stokes flow regime, where nonlinear inertia effects are neglected. In this work we study the inertia effects on the electrodeformation of a viscous drop under a DC electric field using a novel second-order immersed interface method. The inertia effects are quantified by the Ohnesorge number Oh, and the electric field is characterized by an electric capillary number Ca_{E}. Below the critical Ca_{E}, small to moderate electric field strength gives rise to steady equilibrium drop shapes. We found that, at a fixed Ca_{E}, inertia effects induce larger deformation for an oblate drop than a prolate drop, consistent with previous results in the literature. Moreover, our simulations results indicate that inertia effects on the equilibrium drop deformation are dictated by the direction of normal electric stress on the drop interface: Larger drop deformation is found when the normal electric stress points outward, and smaller drop deformation is found otherwise. To our knowledge, such inertia effects on the equilibrium drop deformation has not been reported in the literature. Above the critical Ca_{E}, no steady equilibrium drop deformation can be found, and often the drop breaks up into a number of daughter droplets. In particular, our Navier-Stokes simulations show that, for the parameters we use, (1) daughter droplets are larger in the presence of inertia, (2) the drop deformation evolves more rapidly compared to creeping flow, and (3) complex distribution of electric stresses for drops with inertia effects. Our results suggest that normal electric pressure may be a useful tool in predicting drop pinch-off in oblate deformations.
Decoupling Identification for Serial Two-Link Two-Inertia System
Oaki, Junji; Adachi, Shuichi
The purpose of our study is to develop a precise model by applying the technique of system identification for the model-based control of a nonlinear robot arm, under taking joint-elasticity into consideration. We previously proposed a systematic identification method, called “decoupling identification,” for a “SCARA-type” planar two-link robot arm with elastic joints caused by the Harmonic-drive® reduction gears. The proposed method serves as an extension of the conventional rigid-joint-model-based identification. The robot arm is treated as a serial two-link two-inertia system with nonlinearity. The decoupling identification method using link-accelerometer signals enables the serial two-link two-inertia system to be divided into two linear one-link two-inertia systems. The MATLAB®'s commands for state-space model estimation are utilized in the proposed method. Physical parameters such as motor inertias, link inertias, joint-friction coefficients, and joint-spring coefficients are estimated through the identified one-link two-inertia systems using a gray-box approach. This paper describes accuracy evaluations using the two-link arm for the decoupling identification method under introducing closed-loop-controlled elements and varying amplitude-setup of identification-input. Experimental results show that the identification method also works with closed-loop-controlled elements. Therefore, the identification method is applicable to a “PUMA-type” vertical robot arm under gravity.
International Nuclear Information System (INIS)
Ruspini, L.C.
2012-01-01
Highlights: ► The stability influence of piping fluid inertia on two-phase instabilities is studied. ► Inlet inertia stabilizes the system while outlet inertia destabilizes it. ► High-order modes oscillations are found and analyzed. ► The effect of compressible volumes in the system is studied. ► Inlet compressibility destabilizes the system while outlet comp. stabilizes it. - Abstract: The most common kind of static and dynamic two-phase flow instabilities namely Ledinegg and density wave oscillations are studied. A new model to study two-phase flow instabilities taking into account general parameters from real systems is proposed. The stability influence of external parameters such as the fluid inertia and the presence of compressible gases in the system is analyzed. High-order oscillation modes are found to be related with the fluid inertia of external piping. The occurrence of high-order modes in experimental works is analyzed with focus on the results presented in this work. Moreover, both inertia and compressibility are proven to have a high impact on the stability limits of the systems. The performed study is done by modeling the boiling channel using a one dimensional equilibrium model. An incompressible transient model describes the evolution of the flow and pressure in the non-heated regions and an ideal gas model is used to simulate the compressible volumes in the system. The use of wavelet decomposition analysis is proven to be an efficient tool in stability analysis of several frequencies oscillations.
Testing quantised inertia on emdrives with dielectrics
McCulloch, M. E.
2017-05-01
Truncated-cone-shaped cavities with microwaves resonating within them (emdrives) move slightly towards their narrow ends, in contradiction to standard physics. This effect has been predicted by a model called quantised inertia (MiHsC) which assumes that the inertia of the microwaves is caused by Unruh radiation, more of which is allowed at the wide end. Therefore, photons going towards the wide end gain inertia, and to conserve momentum the cavity must move towards its narrow end, as observed. A previous analysis with quantised inertia predicted a controversial photon acceleration, which is shown here to be unnecessary. The previous analysis also mispredicted the thrust in those emdrives with dielectrics. It is shown here that having a dielectric at one end of the cavity is equivalent to widening the cavity at that end, and when dielectrics are considered, then quantised inertia predicts these results as well as the others, except for Shawyer's first test where the thrust is predicted to be the right size but in the wrong direction. As a further test, quantised inertia predicts that an emdrive's thrust can be enhanced by using a dielectric at the wide end.
A vacuum--generated inertia reaction force
International Nuclear Information System (INIS)
Rueda, Alfonso; Haisch, Bernard
2001-01-01
A clear and succinct covariant approach shows that, in principle, there must be a contribution to the inertia reaction force on an accelerated object by the surrounding vacuum electromagnetic field in which the object is embedded. No details of the vacuum to object electromagnetic interaction need to be specified other than the fact that the object is made of electromagnetically interacting particles. Some interesting consequences of this feature are discussed. This analysis strongly supports the concept that inertia is indeed an opposition of the vacuum fields to any attempt to change the uniform state of motion of material bodies. This also definitely shows that inertia should be viewed as extrinsic to mass and that causing agents and/or mechanisms responsible for the inertia reaction force are neither intrinsic to the notion of mass nor to the entities responsible for the existence of mass in elementary particles (as, e.g., the Higgs field). In other words the mechanism that produces the inertia-reaction-force requires an explicit explanation. This explicit explanation is that inertia is an opposition of the vacuum fields to the accelerated motion of any material entities, i.e., of entities that possess mass. It is briefly commented why the existence of a Higgs field responsible for the generation of mass in elementary particles does not contradict the view presented here. It is also briefly discussed why a strict version of Mach's Principle does really contradict this view, though a broad sense version of Mach's Principle may be in agreement
Study on Inertia as a Gravity Induced Property of Mass, in an Infinite Hubble Expanding Universe
Directory of Open Access Journals (Sweden)
Jeroen van Engelshoven
2013-01-01
Full Text Available Mass is experienced to have two intrinsic properties: inertia (resistance to acceleration and gravity (attraction to other masses. In this paper we evaluate the gravitational effect of all masses of the universe on an accelerated mass, starting from linearized general relativity. The gravitational interaction of all masses in a finite static universe model is shown to create a finite resistance to acceleration, which is inertia. Then, we propose a generalization of the linearized theory and evaluate the Hubble expanding universe. It is shown that the gravitational impact of an infinite expanding universe creates finite inertia, according to . The Friedmann critical mass density is found to be valid. The Mach principle is made explicit. The value and sign of the gravitational constant G are found to be of no consequence on an astronomical scale.
Hansen, J S; Daivis, Peter J; Todd, B D
2009-10-01
In this paper we present equilibrium molecular-dynamics results for the shear, rotational, and spin viscosities for fluids composed of linear molecules. The density dependence of the shear viscosity follows a stretched exponential function, whereas the rotational viscosity and the spin viscosities show approximately power-law dependencies. The frequency-dependent shear and spin viscosities are also studied. It is found that viscoelastic behavior is first manifested in the shear viscosity and that the real part of the spin viscosities features a maximum for nonzero frequency. The calculated transport coefficients are used together with the extended Navier-Stokes equations to investigate the effect of the coupling between the intrinsic angular momentum and linear momentum for highly confined fluids. Both steady and oscillatory flows are studied. It is shown, for example, that the fluid flow rate for Poiseuille flow is reduced by up to 10% in a 2 nm channel for a buta-triene fluid at density 236 kg m(-3) and temperature 306 K. The coupling effect may, therefore, become very important for nanofluidic applications.
On the macroscopic modeling of dilute emulsions under flow in the presence of particle inertia
Mwasame, Paul M.; Wagner, Norman J.; Beris, Antony N.
2018-03-01
Recently, Mwasame et al. ["On the macroscopic modeling of dilute emulsions under flow," J. Fluid Mech. 831, 433 (2017)] developed a macroscopic model for the dynamics and rheology of a dilute emulsion with droplet morphology in the limit of negligible particle inertia using the bracket formulation of non-equilibrium thermodynamics of Beris and Edwards [Thermodynamics of Flowing Systems: With Internal Microstructure (Oxford University Press on Demand, 1994)]. Here, we improve upon that work to also account for particle inertia effects. This advance is facilitated by using the bracket formalism in its inertial form that allows for the natural incorporation of particle inertia effects into macroscopic level constitutive equations, while preserving consistency to the previous inertialess approximation in the limit of zero inertia. The parameters in the resultant Particle Inertia Thermodynamically Consistent Ellipsoidal Emulsion (PITCEE) model are selected by utilizing literature-available mesoscopic theory for the rheology at small capillary and particle Reynolds numbers. At steady state, the lowest level particle inertia effects can be described by including an additional non-affine inertial term into the evolution equation for the conformation tensor, thereby generalizing the Gordon-Schowalter time derivative. This additional term couples the conformation and vorticity tensors and is a function of the Ohnesorge number. The rheological and microstructural predictions arising from the PITCEE model are compared against steady-shear simulation results from the literature. They show a change in the signs of the normal stress differences that is accompanied by a change in the orientation of the major axis of the emulsion droplet toward the velocity gradient direction with increasing Reynolds number, capturing the two main signatures of particle inertia reported in simulations.
Virtual Inertia: Current Trends and Future Directions
Directory of Open Access Journals (Sweden)
Ujjwol Tamrakar
2017-06-01
Full Text Available The modern power system is progressing from a synchronous machine-based system towards an inverter-dominated system, with large-scale penetration of renewable energy sources (RESs like wind and photovoltaics. RES units today represent a major share of the generation, and the traditional approach of integrating them as grid following units can lead to frequency instability. Many researchers have pointed towards using inverters with virtual inertia control algorithms so that they appear as synchronous generators to the grid, maintaining and enhancing system stability. This paper presents a literature review of the current state-of-the-art of virtual inertia implementation techniques, and explores potential research directions and challenges. The major virtual inertia topologies are compared and classified. Through literature review and simulations of some selected topologies it has been shown that similar inertial response can be achieved by relating the parameters of these topologies through time constants and inertia constants, although the exact frequency dynamics may vary slightly. The suitability of a topology depends on system control architecture and desired level of detail in replication of the dynamics of synchronous generators. A discussion on the challenges and research directions points out several research needs, especially for systems level integration of virtual inertia systems.
International Nuclear Information System (INIS)
Paraschivoiu, I.; Prud'homme, M.; Robillard, L.; Vasseur, P.
2003-01-01
This book constitutes at the same time theoretical and practical base relating to the phenomena associated with fluid mechanics. The concept of continuum is at the base of the approach developed in this work. The general advance proceeds of simple balances of forces as into hydrostatic to more complex situations or inertias, the internal stresses and the constraints of Reynolds are taken into account. This advance is not only theoretical but contains many applications in the form of solved problems, each chapter ending in a series of suggested problems. The major part of the applications relates to the incompressible flows
Kπ=0+ band moment of inertia anomaly
International Nuclear Information System (INIS)
Zeng, J.Y.; Wu, C.S.; Cheng, L.; Lin, C.Z.; China Center of Advanced Science and Technology
1990-01-01
The moments of inertia of K π =0 + bands in the well-deformed nuclei are calculated by a particle-number-conserving treatment for the cranked shell model. The very accurate solutions to the low-lying K π =0 + bands are obtained by making use of an effective K truncation. Calculations show that the main contribution to the moments of inertia comes from the nucleons in the intruding high-j orbits. Considering the fact that no free parameter is involved in the calculation and no extra inert core contribution is added, the agreement between the calculated and the observed moments of inertia of 0 + bands in 168 Er is very satisfactory
Thermal inertia and surface heterogeneity on Mars
Putzig, Nathaniel E.
Thermal inertia derived from temperature observations is critical for understanding surface geology and assessing potential landing sites on Mars. Derivation methods generally assume uniform surface properties for any given observation. Consequently, horizontal heterogeneity and near-surface layering may yield apparent thermal inertia that varies with time of day and season. To evaluate the effects of horizontal heterogeneity, I modeled the thermal behavior of surfaces containing idealized material mixtures (dust, sand, duricrust, and rocks) and differing slope facets. These surfaces exhibit diurnal and seasonal variability in apparent thermal inertia of several 100 tiu, 1 even for components with moderately contrasting thermal properties. To isolate surface effects on the derived thermal inertia of Mars, I mapped inter- annual and seasonal changes in albedo and atmospheric dust opacity, accounting for their effects in a modified derivation algorithm. Global analysis of three Mars years of MGS-TES 2 data reveals diurnal and seasonal variations of ~200 tiu in the mid-latitudes and 600 tiu or greater in the polar regions. Correlation of TES results and modeled apparent thermal inertia of heterogeneous surfaces indicates pervasive surface heterogeneity on Mars. At TES resolution, the near-surface thermal response is broadly dominated by layering and is consistent with the presence of duricrusts over fines in the mid-latitudes and dry soils over ground ice in the polar regions. Horizontal surface mixtures also play a role and may dominate at higher resolution. In general, thermal inertia obtained from single observations or annually averaged maps may misrepresent surface properties. In lieu of a robust heterogeneous- surface derivation technique, repeat coverage can be used together with forward-modeling results to constrain the near-surface heterogeneity of Mars. 1 tiu == J m -2 K -1 s - 2 Mars Global Surveyor Thermal Emission Spectrometer
Filament stretching rheometer: inertia compensation revisited
DEFF Research Database (Denmark)
Szabo, Peter; McKinley, Gareth H.
2003-01-01
The necessary inertia compensation used in the force balance for the filament stretching rheometer is derived for an arbitrary frame of reference. This enables the force balance to be used to extract correctly the extensional viscosity from measurements of the tensile force at either end of the e......The necessary inertia compensation used in the force balance for the filament stretching rheometer is derived for an arbitrary frame of reference. This enables the force balance to be used to extract correctly the extensional viscosity from measurements of the tensile force at either end...
Nuclear moments of inertia at high spin
International Nuclear Information System (INIS)
Deleplanque, M.A.
1982-10-01
The competition between collective motion and alignment at high spin can be evaluated by measuring two complementary dynamic moments of inertia. The first, I band, measured in γ-γ correlation experiments, relates to the collective properties of the nucleus. A new moment of inertia I/sub eff/ is defined here, which contains both collective and alignment effects. Both of these can be measured in continuum γ-ray spectra of rotational nuclei up to high frequencies. The evolution of γ-ray spectra for Er nuclei from mass 160 to 154 shows that shell effects can directly be observed in the spectra of the lighter nuclei
Parallel algorithms for computation of the manipulator inertia matrix
Amin-Javaheri, Masoud; Orin, David E.
1989-01-01
The development of an O(log2N) parallel algorithm for the manipulator inertia matrix is presented. It is based on the most efficient serial algorithm which uses the composite rigid body method. Recursive doubling is used to reformulate the linear recurrence equations which are required to compute the diagonal elements of the matrix. It results in O(log2N) levels of computation. Computation of the off-diagonal elements involves N linear recurrences of varying-size and a new method, which avoids redundant computation of position and orientation transforms for the manipulator, is developed. The O(log2N) algorithm is presented in both equation and graphic forms which clearly show the parallelism inherent in the algorithm.
Fluid-structure coupling for an oscillating hydrofoil
Münch, C.; Ausoni, P.; Braun, O.; Farhat, M.; Avellan, F.
2010-08-01
Fluid-structure investigations in hydraulic machines using coupled simulations are particularly time-consuming. In this study, an alternative method is presented that linearizes the hydrodynamic load of a rigid, oscillating hydrofoil. The hydrofoil, which is surrounded by incompressible, turbulent flow, is modeled with forced and free pitching motions, where the mean incidence angle is 0° with a maximum angle amplitude of 2°. Unsteady simulations of the flow, performed with ANSYS CFX, are presented and validated with experiments which were carried out in the EPFL High-Speed Cavitation Tunnel. First, forced motion is investigated for reduced frequencies ranging from 0.02 to 100. The hydrodynamic load is modeled as a simple combination of inertia, damping and stiffness effects. As expected, the potential flow analysis showed the added moment of inertia is constant, while the fluid damping and the fluid stiffness coefficients depend on the reduced frequency of the oscillation motion. Behavioral patterns were observed and two cases were identified depending on if vortices did or did not develop in the hydrofoil wake. Using the coefficients identified in the forced motion case, the time history of the profile incidence is then predicted analytically for the free motion case and excellent agreement is found for the results from coupled fluid-structure simulations. The model is validated and may be extended to more complex cases, such as blade grids in hydraulic machinery.
Nonlinear Inertia Classification Model and Application
Directory of Open Access Journals (Sweden)
Mei Wang
2014-01-01
Full Text Available Classification model of support vector machine (SVM overcomes the problem of a big number of samples. But the kernel parameter and the punishment factor have great influence on the quality of SVM model. Particle swarm optimization (PSO is an evolutionary search algorithm based on the swarm intelligence, which is suitable for parameter optimization. Accordingly, a nonlinear inertia convergence classification model (NICCM is proposed after the nonlinear inertia convergence (NICPSO is developed in this paper. The velocity of NICPSO is firstly defined as the weighted velocity of the inertia PSO, and the inertia factor is selected to be a nonlinear function. NICPSO is used to optimize the kernel parameter and a punishment factor of SVM. Then, NICCM classifier is trained by using the optical punishment factor and the optical kernel parameter that comes from the optimal particle. Finally, NICCM is applied to the classification of the normal state and fault states of online power cable. It is experimentally proved that the iteration number for the proposed NICPSO to reach the optimal position decreases from 15 to 5 compared with PSO; the training duration is decreased by 0.0052 s and the recognition precision is increased by 4.12% compared with SVM.
Topology optimization of inertia driven dosing units
DEFF Research Database (Denmark)
Andreasen, Casper Schousboe
2017-01-01
This paper presents a methodology for optimizing inertia driven dosing units, sometimes referred to as eductors, for use in small scale flow applications. The unit is assumed to operate at low to moderate Reynolds numbers and under steady state conditions. By applying topology optimization...
Effects of Inertia on Evolutionary Prisoner's Dilemma Game
Du, Wen-Bo; Cao, Xian-Bin; Liu, Run-Ran; Wang, Zhen
2012-09-01
Considering the inertia of individuals in real life, we propose a modified Fermi updating rule, where the inertia of players is introduced into evolutionary prisoner's dilemma game (PDG) on square lattices. We mainly focus on how the inertia affects the cooperative behavior of the system. Interestingly, we find that the cooperation level has a nonmonotonic dependence on the inertia: with small inertia, cooperators will soon be invaded by defectors; with large inertia, players are unwilling to change their strategies and the cooperation level remains the same as the initial state; while a moderate inertia can induce the highest cooperation level. Moreover, effects of environmental noise and individual inertia are studied. Our work may be helpful in understanding the emergence and persistence of cooperation in nature and society.
Effects of Inertia on Evolutionary Prisoner's Dilemma Game
International Nuclear Information System (INIS)
Du Wenbo; Cao Xianbin; Liu Runran; Wang Zhen
2012-01-01
Considering the inertia of individuals in real life, we propose a modified Fermi updating rule, where the inertia of players is introduced into evolutionary prisoner's dilemma game (PDG) on square lattices. We mainly focus on how the inertia affects the cooperative behavior of the system. Interestingly, we find that the cooperation level has a nonmonotonic dependence on the inertia: with small inertia, cooperators will soon be invaded by defectors; with large inertia, players are unwilling to change their strategies and the cooperation level remains the same as the initial state; while a moderate inertia can induce the highest cooperation level. Moreover, effects of environmental noise and individual inertia are studied. Our work may be helpful in understanding the emergence and persistence of cooperation in nature and society. (interdisciplinary physics and related areas of science and technology)
Directory of Open Access Journals (Sweden)
M. Farooq
Full Text Available This article studies MHD double stratified stagnation point flow of Carreau fluid towards a non linear stretchable surface with radiation. Features of heat and mass transfer are evaluated by using convective boundary conditions. Resulting nonlinear problems are solved and studied for the velocity, temperature and concentration fields. Heat and mass transfer rates in addition to skin friction are discussed. Besides this for the verification of the present findings, the results of presented analysis have been compared with the available works in particular situations and reasonable agreement is noted. Keywords: Convective boundary condition, Thermal radiation, Double stratification, Stagnation point flow
Experimental study of the moment of inertia of a cone-angular variation and inertia ellipsoid
International Nuclear Information System (INIS)
Pintao, Carlos A F; Souza de Filho, Moacir P; Usida, Wesley F; Xavier, Jose A
2007-01-01
In this paper, an experimental set-up which differs from the traditional ones is established in order to determine the moment of inertia of a right circular cone. Its angular variation and inertia ellipsoid are determined by means of an experimental study. In addition, a system that allows for the evaluation of the angular acceleration and torque through electric current or frequency measurement is utilized
Dependence of nuclear moments of inertia on the triaxial parameter
International Nuclear Information System (INIS)
Helgesson, J.; Hamamoto, Ikuko
1989-01-01
The dependence of nuclear moments of inertia on the triaxial parameter (γ-variable) is investigated including both the Belyaev term and the Migdal term. The obtained dependence is compared with that of hydrodynamical moments of inertia and other moments of inertia used conventionally. (orig.)
Ma, J. Z. G.; Hirose, A.
2010-05-01
Lower-hybrid (LH) oscillitons reveal one aspect of geocomplexities. They have been observed by rockets and satellites in various regions in geospace. They are extraordinary solitary waves the envelop of which has a relatively longer period, while the amplitude is modulated violently by embedded oscillations of much shorter periods. We employ a two-fluid (electron-ion) slab model in a Cartesian geometry to expose the excitation of LH oscillitons. Relying on a set of self-similar equations, we first produce, as a reference, the well-known three shapes (sinusoidal, sawtooth, and spiky or bipolar) of parallel-propagating ion-acoustic (IA) solitary structures in the absence of electron inertia, along with their Fast Fourier Transform (FFT) power spectra. The study is then expanded to illustrate distorted structures of the IA modes by taking into account all the three components of variables. In this case, the ion-cyclotron (IC) mode comes into play. Furthermore, the electron inertia is incorporated in the equations. It is found that the inertia modulates the coupled IA/IC envelops to produce LH oscillitons. The newly excited structures are characterized by a normal low-frequency IC solitary envelop embedded by high-frequency, small-amplitude LH oscillations which are superimposed upon by higher-frequency but smaller-amplitude IA ingredients. The oscillitons are shown to be sensitive to several input parameters (e.g., the Mach number, the electron-ion mass/temperature ratios, and the electron thermal speed). Interestingly, whenever a LH oscilliton is triggered, there occurs a density cavity the depth of which can reach up to 20% of the background density, along with density humps on both sides of the cavity. Unexpectedly, a mode at much lower frequencies is also found beyond the IC band. Future studies are finally highlighted. The appendices give a general dispersion relation and specific ones of linear modes relevant to all the nonlinear modes encountered in the text.
Emergency Entry with One Control Torque: Non-Axisymmetric Diagonal Inertia Matrix
Llama, Eduardo Garcia
2011-01-01
In another work, a method was presented, primarily conceived as an emergency backup system, that addressed the problem of a space capsule that needed to execute a safe atmospheric entry from an arbitrary initial attitude and angular rate in the absence of nominal control capability. The proposed concept permits the arrest of a tumbling motion, orientation to the heat shield forward position and the attainment of a ballistic roll rate of a rigid spacecraft with the use of control in one axis only. To show the feasibility of such concept, the technique of single input single output (SISO) feedback linearization using the Lie derivative method was employed and the problem was solved for different number of jets and for different configurations of the inertia matrix: the axisymmetric inertia matrix (I(sub xx) > I(sub yy) = I(sub zz)), a partially complete inertia matrix with I(sub xx) > I(sub yy) > I(sub zz), I(sub xz) not = 0 and a realistic complete inertia matrix with I(sub xx) > I(sub yy) > I)sub zz), I(sub ij) not= 0. The closed loop stability of the proposed non-linear control on the total angle of attack, Theta, was analyzed through the zero dynamics of the internal dynamics for the case where the inertia matrix is axisymmetric (I(sub xx) > I(sub yy) = I(sub zz)). This note focuses on the problem of the diagonal non-axisymmetric inertia matrix (I(sub xx) > I(sub yy) > I(sub zz)), which is half way between the axisymmetric and the partially complete inertia matrices. In this note, the control law for this type of inertia matrix will be determined and its closed-loop stability will be analyzed using the same methods that were used in the other work. In particular, it will be proven that the control system is stable in closed-loop when the actuators only provide a roll torque.
Effects of microscale inertia on heat or mass transfer from a drop
Krishnamurthy, Deepak; Subramanian, Ganesh
2012-11-01
Heat or mass transport from suspensions of solid particles or drops is ubiquitous in many industrial processes. In the zero inertia limit the transport is diffusion limited owing to the presence of closed streamlines around each particle. A small but finite amount of inertia though, results in a vastly different picture, greatly enhancing transport by destroying the closed streamline configuration. We develop a theoretical formulation to study the effects of weak inertia on transport from a density-matched drop in a 2D linear flow. It is shown that, unlike a solid particle, the near-surface streamlines are closed only when the viscosity ratio (λ) exceeds a critical value λc = 2 α / (1- α) , where α is the linear flow parameter measuring relative magnitudes of extension and vorticity. The velocity field on the drop surface can be characterized using a complex-valued analogue of the (C, τ) coordinate system used to describe Jeffrey orbits of an axisymmetric particle. In the open-streamline case (λ λ c) , similar to the solid particle, inertia plays a crucial role, and the Nusselt number must scale as G(α, λ)Re1/2Pe1/2. A methodology is developed to analyze the convection along spiraling streamlines using a physically motivated choice of coordinate system on the drop surface.
Dagrau, Franck; Coulouvrat, François; Marchiano, Régis; Héron, Nicolas
2008-06-01
Dassault Aviation as a civil aircraft manufacturer is studying the feasibility of a supersonic business jet with the target of an "acceptable" sonic boom at the ground level, and in particular in case of focusing. A sonic boom computational process has been performed, that takes into account meteorological effects and aircraft manoeuvres. Turn manoeuvres and aircraft acceleration create zones of convergence of rays (caustics) which are the place of sound amplification. Therefore two elements have to be evaluated: firstly the geometrical position of the caustics, and secondly the noise level in the neighbourhood of the caustics. The modelling of the sonic boom propagation is based essentially on the assumptions of geometrical acoustics. Ray tracing is obtained according to Fermat's principle as paths that minimise the propagation time between the source (the aircraft) and the receiver. Wave amplitude and time waveform result from the solution of the inviscid Burgers' equation written along each individual ray. The "age variable" measuring the cumulative nonlinear effects is linked to the ray tube area. Caustics are located as the place where the ray tube area vanishes. Since geometrical acoustics does not take into account diffraction effects, it breaks down in the neighbourhood of caustics where it would predict unphysical infinite pressure amplitude. The aim of this study is to describe an original method for computing the focused noise level. The approach involves three main steps that can be summarised as follows. The propagation equation is solved by a forward marching procedure split into three successive steps: linear propagation in a homogeneous medium, linear perturbation due to the weak heterogeneity of the medium, and non-linear effects. The first step is solved using an "exact" angular spectrum algorithm. Parabolic approximation is applied only for the weak perturbation due to the heterogeneities. Finally, non linear effects are performed by solving the
Nonlinear transient waves in coupled phase oscillators with inertia.
Jörg, David J
2015-05-01
Like the inertia of a physical body describes its tendency to resist changes of its state of motion, inertia of an oscillator describes its tendency to resist changes of its frequency. Here, we show that finite inertia of individual oscillators enables nonlinear phase waves in spatially extended coupled systems. Using a discrete model of coupled phase oscillators with inertia, we investigate these wave phenomena numerically, complemented by a continuum approximation that permits the analytical description of the key features of wave propagation in the long-wavelength limit. The ability to exhibit traveling waves is a generic feature of systems with finite inertia and is independent of the details of the coupling function.
The latent effect of inertia in the modal choice
DEFF Research Database (Denmark)
Cherchi, Elisabetta; Meloni, Italo; Ortúzar, Juan de Dios
2014-01-01
The existence of habit (leading to inertia) in the choice process has been approached in the literature in a number of ways. In transport, inertia has been studied mainly using “long panel” data, or mixed revealed and stated preference data. In these studies inertia links the choice made in two...... approaches. We assume that inertia is revealed by past behaviour and affects also the initial condition, but we recognise that past behaviour is only an indicator of habitual behaviour, the true process behind the formation of habitual behaviour being latent. We estimate a hybrid choice model using a set...... of revealed and stated mode choice preferences collected in Cagliari (Italy). We found a significant latent inertia in the revealed preference data, indicating that inertia affects the initial conditions. The latent inertia is revealed by the frequency of past behaviour but the effect of trip frequency...
Nuclear moments of inertia at high spins
International Nuclear Information System (INIS)
Deleplanque, M.A.
1984-01-01
For nuclei in high spin states a yrast-like part of a continuum γ-ray spectrum shows naturally how angular momentum is generated as a function of frequency. In rotational nuclei, the rotational frequency is omega = dE/dI approx. E/sub γ/2, half the collective E2 transition energy. The height of the spectrum for a rotor is proportional to dN/dE/sub γ/ = dI/4d omega. dI/d omega is a dynamic (second derivative of energy with spin) moment of inertia. It contains both alignments and collective effects and is therefore an effective moment of inertia J/sub eff//sup (2)/. It shows how much angular momentum is generated at each frequency. If the collective moment of inertia J/sub band//sup (2)/(omega) is measured (from γ-γ correlation experiments) for the same system, the collective and aligned (Δi) contributions to the increase of angular momentum ΔI in a frequency interval Δ omega can be separated: Δi/ΔI = 1 - J/sub band//sup (2)//J/sub eff//sup (2)/. This is at present the only way to extract such detailed information at the highest spin states where discrete lines cannot be resolved. An example of the spectra obtained in several Er nuclei is shown. They are plotted in units of the moment of inertia J/sub eff//sup (2)/. The high-energy part of the spectra has been corrected for incomplete feeding at these frequencies
Bounds on the mass and the moment of inertia of nonrotating neutron stars
International Nuclear Information System (INIS)
Sabbadini, A.G.
1976-01-01
Bounds are placed on the mass and the moment of inertia of relativistic, spherical, perfect fluid neutron stars, under minimal assumptions on the equation of state of neutron star matter above nuclear densities. The assumptions are: the pressure p, the density rho, and the derivative dp/d rho are positive. The equation of state is assumed to be known below the density rho 0 = 5 x 10 14 g/cm 3 . The upper bound on the mass of a nonrotating neutron star, under these assumptions, is found to be 5 M/sub solar mass/. Upper and lower bounds on the moment of inertia are derived: for a spherical star of given mass and radius (without assuming a specific equation of state in any density region); for a spherical neutron star of arbitrary mass and radius; for a spherical neutron star of given mass. These bounds are optimum ones, in the sense that there always exists a configuration consistent with the assumptions, having a moment of inertia equal to the bound. Using these results for the moment of inertia, the correction to the upper bound on the mass due to slow rotation is discussed
A new hybrid code (CHIEF) implementing the inertial electron fluid equation without approximation
Muñoz, P. A.; Jain, N.; Kilian, P.; Büchner, J.
2018-03-01
We present a new hybrid algorithm implemented in the code CHIEF (Code Hybrid with Inertial Electron Fluid) for simulations of electron-ion plasmas. The algorithm treats the ions kinetically, modeled by the Particle-in-Cell (PiC) method, and electrons as an inertial fluid, modeled by electron fluid equations without any of the approximations used in most of the other hybrid codes with an inertial electron fluid. This kind of code is appropriate to model a large variety of quasineutral plasma phenomena where the electron inertia and/or ion kinetic effects are relevant. We present here the governing equations of the model, how these are discretized and implemented numerically, as well as six test problems to validate our numerical approach. Our chosen test problems, where the electron inertia and ion kinetic effects play the essential role, are: 0) Excitation of parallel eigenmodes to check numerical convergence and stability, 1) parallel (to a background magnetic field) propagating electromagnetic waves, 2) perpendicular propagating electrostatic waves (ion Bernstein modes), 3) ion beam right-hand instability (resonant and non-resonant), 4) ion Landau damping, 5) ion firehose instability, and 6) 2D oblique ion firehose instability. Our results reproduce successfully the predictions of linear and non-linear theory for all these problems, validating our code. All properties of this hybrid code make it ideal to study multi-scale phenomena between electron and ion scales such as collisionless shocks, magnetic reconnection and kinetic plasma turbulence in the dissipation range above the electron scales.
Moments of inertia of neutron stars
Energy Technology Data Exchange (ETDEWEB)
Greif, Svenja Kim; Hebeler, Kai; Schwenk, Achim [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (Germany)
2016-07-01
Neutron stars are unique laboratories for matter at extreme conditions. While nuclear forces provide systematic constraints on properties of neutron-rich matter up to around nuclear saturation density, the composition of matter at high densities is still unknown. Recent precise observations of 2 M {sub CircleDot} neutron stars made it possible to derive systematic constraints on the equation of state at high densities and also neutron star radii. Further improvements of these constraints require the observation of even heavier neutron stars or a simultaneous measurement of mass and radius of a single neutron star. Since the precise measurement of neutron star radii is an inherently difficult problem, the observation of moment of inertia of neutron stars provides a promising alternative, since they can be measured by pulsar timing experiments. We present a theoretical framework that allows to calculate moments of inertia microscopically, we show results based on state of the art equations of state and illustrate how future measurements of moments of inertia allow to constrain the equation of state and other properties of neutron stars.
Mass and Inertia Parameters for Nuclear Fission
International Nuclear Information System (INIS)
Damgaard, J.; Pauli, H.C.; Strutinsky, V.M.; Wong, C.Y.; Brack, M.; Stenholm-Jensen, A.
1969-01-01
The effective mass parameter and the moments of inertia for a deformed nucleus are evaluated using the cranking-model formalism. Special attention is paid to the dependence of these quantities on the intrinsic structure, which may arise due to shells in deformed nuclei. It is found that these inertial parameters are very much influenced by the shells present. The effective-mass parameter, which appears in an important way in the theory of spontaneous fission, fluctuates in the same manner as the shell-energy corrections. Its values at the fission barrier are up to two or three times larger than those at the equilibrium minima. This correlation comes about because for the effective mass the change in the local density of single-particle states is very important, much more so than the change in the pairing correlation. The moments of inertia which enter in the theory of angular anisotropy of fission fragments, also fluctuate as a function of the deformation. At low temperatures, the fluctuation is large and shows a distinct but more complicated correlation with the shells. At high temperatures, the moments of inertia fluctuate with a smaller amplitude about the rigid-body value in correlation with the energy-shell corrections. For the first-and second barriers, the rigid-body values are essentially reached at a nuclear temperature of 0.8 to 1.0 MeV. (author)
Exploring inertia in a typical state organisation
Directory of Open Access Journals (Sweden)
G. J. Louw
2004-10-01
Full Text Available Those organisations which do not change according to environmental pressures, suffer from organisational inertia. The purpose of this study is to explore the manifestation of organisational inertia in the target organisation. The target population for this study was a group of trainees, representing the geographic and demographic levels of a particular state department. In South Africa, surveys of this nature were only executed in the corporate sector. The results indicate that organisational inertia is a phenomenon that affects both corporate and governmental organisations. Opsomming Organisasies wat nie ooreenkomstig omgewingsdruk verander nie, ly aan organisasietraagheid. Die doel van die studie is om organisasietraagheid te konseptualiseer en die manifestasie daarvan in die teikenorganisasie te ondersoek. Die teikenpopulasie bestaan uit ’n groep kursusgangers wat die demografiese en geografiese samestelling van ‘n tipiese staatsdepartement verteenwoordig. In Suid -Afrika is navorsing van hierdie aard nog net in die korporatiewe sektor uitgevoer. Die resultate toon aan dat organisasietraagheid ‘n faktor is wat beide die korporatiewe omgewing en staatsorganisasies beïnvloed.
Directory of Open Access Journals (Sweden)
Steven M. Nesbit
2006-06-01
Full Text Available This paper discusses the inertia tensors of tennis rackets and their influence on the elbow swing torques in a forehand motion, the loadings transmitted to the elbow from central and eccentric impacts, and the racket acceleration responses from central and eccentric impacts. Inertia tensors of various rackets with similar mass and mass center location were determined by an inertia pendulum and were found to vary considerably in all three orthogonal directions. Tennis swing mechanics and impact analyses were performed using a computer model comprised of a full-body model of a human, a parametric model of the racket, and an impact function. The swing mechanics analysis of a forehand motion determined that inertia values had a moderate linear effect on the pronation-supination elbow torques required to twist the racket, and a minor effect on the flexion-extension and valgus-varus torques. The impact analysis found that mass center inertia values had a considerable effect on the transmitted torques for both longitudinal and latitudinal eccentric impacts and significantly affected all elbow torque components. Racket acceleration responses to central and eccentric impacts were measured experimentally and found to be notably sensitive to impact location and mass center inertia values
Directory of Open Access Journals (Sweden)
Azadeh Hashemian
2008-06-01
Full Text Available Enhanced surface heat exchangers are commonly used all worldwide. If applicable, due to their complicated geometry, simulating corrugated plate heat exchangers is a time-consuming process. In the present study, first we simulate the heat transfer in a sharp V-shape corrugation cell with constant temperature walls; then, we use a Locally Linear Neuro-Fuzzy method based on a radial basis function (RBFs to model the temperature field in the whole channel. New approach is developed to deal with fast computational and low memory resources that can be used with the largest available data sets. The purpose of the research is to reveal the advantages of proposed Neuro-Fuzzy model as a powerful modeling system designed for predicting and to make a fair comparison between it and the successful FLUENT simulated approaches in its best structures.
Reduced viscosity interpreted for fluid/gas mixtures
Lewis, D. H.
1981-01-01
Analysis predicts decrease in fluid viscosity by comparing pressure profile of fluid/gas mixture with that of power-law fluid. Fluid is taken to be viscous, non-Newtonian, and incompressible; the gas to be ideal; the flow to be inertia-free, isothermal, and one dimensional. Analysis assists in design of flow systems for petroleum, coal, polymers, and other materials.
Inertia in strategy switching transforms the strategy evolution.
Zhang, Yanling; Fu, Feng; Wu, Te; Xie, Guangming; Wang, Long
2011-12-01
A recent experimental study [Traulsen et al., Proc. Natl. Acad. Sci. 107, 2962 (2010)] shows that human strategy updating involves both direct payoff comparison and the cost of switching strategy, which is equivalent to inertia. However, it remains largely unclear how such a predisposed inertia affects 2 × 2 games in a well-mixed population of finite size. To address this issue, the "inertia bonus" (strategy switching cost) is added to the learner payoff in the Fermi process. We find how inertia quantitatively shapes the stationary distribution and that stochastic stability under inertia exhibits three regimes, with each covering seven regions in the plane spanned by two inertia parameters. We also obtain the extended "1/3" rule with inertia and the speed criterion with inertia; these two findings hold for a population above two. We illustrate the above results in the framework of the Prisoner's Dilemma game. As inertia varies, two intriguing stationary distributions emerge: the probability of coexistence state is maximized, or those of two full states are simultaneously peaked. Our results may provide useful insights into how the inertia of changing status quo acts on the strategy evolution and, in particular, the evolution of cooperation.
Frequency Stability Enhancement for Low Inertia Systems using Synthetic Inertia of Wind Power
DEFF Research Database (Denmark)
Nguyen, Ha Thi; Yang, Guangya; Nielsen, Arne Hejde
2017-01-01
stability, this paper proposes supplementary control methods to implement synthetic inertia for doubly-fed induction generator (DFIG) based wind energy system during frequency excursions. Different control strategies and activation schemes are analyzed and implemented on the Western Danish renewable......-based system using-real time digital simulator (RTDS) to propose the best one for the synthetic inertia controller. From the comparative simulation results, it can be concluded that the method using a combination of both the frequency deviation and derivative as input signals, and the under-frequency trigger...
International Nuclear Information System (INIS)
Chang-Jian, C.-W.; Chen, C.-K.
2008-01-01
This study presents a dynamic analysis of a flexible rotor supported by two porous squeeze couple stress fluid film journal bearings with non-linear suspension. The dynamics of the rotor center and bearing center are studied. The analysis of the rotor-bearing system is investigated under the assumptions of non-Newtonian fluid and a short bearing approximation. The spatial displacements in the horizontal and vertical directions are considered for various non-dimensional speed ratios. The dynamic equations are solved using the Runge-Kutta method. The analysis methods employed in this study is inclusive of the dynamic trajectories of the rotor center and bearing center, power spectra, Poincare maps and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The numerical results show that the stability of the system varies with the non-dimensional speed ratios, the non-dimensional parameter l* and the permeability. The modeling results thus obtained by using the method proposed in this paper can be employed to predict the stability of the rotor-bearing system and the undesirable behavior of the rotor and bearing center can be avoided
Uncovering the inertia of dislocation motion and negative mechanical response in crystals.
Tang, Yizhe
2018-01-09
Dislocations are linear defects in crystals and their motion controls crystals' mechanical behavior. The dissipative nature of dislocation propagation is generally accepted although the specific mechanisms are still not fully understood. The inertia, which is undoubtedly the nature of motion for particles with mass, seems much less convincing for configuration propagation. We utilize atomistic simulations in conditions that minimize dissipative effects to enable uncovering of the hidden nature of dislocation motion, in three typical model metals Mg, Cu and Ta. We find that, with less/no dissipation, dislocation motion is under-damped and explicitly inertial at both low and high velocities. The inertia of dislocation motion is intrinsic, and more fundamental than the dissipative nature. The inertia originates from the kinetic energy imparted from strain energy and stored in the moving core. Peculiar negative mechanical response associated with the inertia is also discovered. These findings shed light on the fundamental nature of dislocation motion, reveal the underlying physics, and provide a new physical explanation for phenomena relevant to high-velocity dislocations.
Influence of the inertia and gravity on the boiling flows stability
International Nuclear Information System (INIS)
Delmastro, D.F.; Clausse, A.
1987-01-01
A study of boiling flows stability on the basis of a linear analysis is presented. From the homogeneous flows' conservation equations, a distributed parameters model, which allows to deal with the frequency field system, is obtained. The adimensional parameters which characterize the inertia effects and the gravity on the impulse equation, are identified. On the other hand, a mean volumes model which permits to gather analytic criteria helpful for the design and comprehension of the problem is developed. (Author)
Sulfates on Mars: TES Observations and Thermal Inertia Data
Cooper, C. D.; Mustard, J. F.
2001-05-01
The high resolution thermal emission spectra returned by the TES spectrometer on the MGS spacecraft have allowed the mapping of a variety of minerals and rock types by different sets of researchers. Recently, we have used a linear deconvolution approach to compare sulfate-palagonite soil mixtures created in the laboratory with Martian surface spectra. This approach showed that a number of areas on Mars have spectral properties that match those of sulfate-cemented soils (but neither loose powder mixtures of sulfates and soils nor sand-sized grains of disaggregated crusted soils). These features do not appear to be caused by atmospheric or instrumental effects and are thus believed to be related to surface composition and texture. The distribution and physical state of sulfate are important pieces of information for interpreting surface processes on Mars. A number of different mechanisms could have deposited sulfate in surface layers. Some of these include evaporation of standing bodies of water, aerosol deposition of volcanic gases, hydrothermal alteration from groundwater, and in situ interaction between the atmosphere and soil. The areas on Mars with cemented sulfate signatures are spread across a wide range of elevations and are generally large in spatial scale. Some of the areas are associated with volcanic regions, but many are in dark red plains that have previously been interpreted as duricrust deposits. Our current work compares the distribution of sulfate-cemented soils as mapped by the spectral deconvolution approach with thermal inertia maps produced from both Viking and MGS-TES. Duricrust regions, interpreted from intermediate thermal inertia values, are large regions thought to be sulfate-cemented soils similar to coherent, sulfate-rich materials seen at the Viking lander sites. Our observations of apparent regions of cemented sulfate are also large in spatial extent. This scale information is important for evaluating formation mechanisms for the
Dynamic analysis of multibody system immersed in a fluid medium
International Nuclear Information System (INIS)
Wu, R.W.; Liu, L.K.; Levy, S.
1977-01-01
This paper is concerned primarily with the development and evaluation of an analysis method for the reponse prediction of immersed systems to seismic and other dynamic excitations. For immersed multibody systems, the hydrodynamic interaction causes coupled motion among the solid bodies. Also, under intense external excitations, impact between bodies may occur. The complex character of such systems inhibit the use of conventional analytical solutions in closed form. Therefore, approximate numerical schemes have been devised. For an incompressible, inviscid fluid, the hydrodynamic forces exerted by the fluid on solid bodies are determined to be linearly proportional to the acceleration of the vibrating solid bodies; i.e., the presence of the fluid only affects the inertia of the solid body system. A finite element computer program has been developed for computing this hydrodynamic (or added) mass effect. This program can be used to determine the hydrodynamic mass of a two-dimensional fluid field with solid bodies of arbitrary geometry. Triangular elements and linear pressure interpolation function are used to discretize the fluid region. The component element method is used to determine the dynamic response of the multibody system to externally applied mechanical loading or support excitation. The present analysis method for predicting the dynamic response of submerged multibody system is quite general and pertains to any number of solid bodies. However in this paper, its application is demonstrated only for 4 and 25 body systems. (Auth.)
Vibration analysis of partially cracked plate submerged in fluid
Soni, Shashank; Jain, N. K.; Joshi, P. V.
2018-01-01
The present work proposes an analytical model for vibration analysis of partially cracked rectangular plates coupled with fluid medium. The governing equation of motion for the isotropic plate based on the classical plate theory is modified to accommodate a part through continuous line crack according to simplified line spring model. The influence of surrounding fluid medium is incorporated in the governing equation in the form of inertia effects based on velocity potential function and Bernoulli's equations. Both partially and totally submerged plate configurations are considered. The governing equation also considers the in-plane stretching due to lateral deflection in the form of in-plane forces which introduces geometric non-linearity into the system. The fundamental frequencies are evaluated by expressing the lateral deflection in terms of modal functions. The assessment of the present results is carried out for intact submerged plate as to the best of the author's knowledge the literature lacks in analytical results for submerged cracked plates. New results for fundamental frequencies are presented as affected by crack length, fluid level, fluid density and immersed depth of plate. By employing the method of multiple scales, the frequency response and peak amplitude of the cracked structure is analyzed. The non-linear frequency response curves show the phenomenon of bending hardening or softening and the effect of fluid dynamic pressure on the response of the cracked plate.
Scaling of rotational inertia of primate mandibles.
Ross, Callum F; Iriarte-Diaz, Jose; Platts, Ellen; Walsh, Treva; Heins, Liam; Gerstner, Geoffrey E; Taylor, Andrea B
2017-05-01
The relative importance of pendulum mechanics and muscle mechanics in chewing dynamics has implications for understanding the optimality criteria driving the evolution of primate feeding systems. The Spring Model (Ross et al., 2009b), which modeled the primate chewing system as a forced mass-spring system, predicted that chew cycle time would increase faster than was actually observed. We hypothesized that if mandibular momentum plays an important role in chewing dynamics, more accurate estimates of the rotational inertia of the mandible would improve the accuracy with which the Spring Model predicts the scaling of primate chew cycle period. However, if mass-related momentum effects are of negligible importance in the scaling of primate chew cycle period, this hypothesis would be falsified. We also predicted that greater "robusticity" of anthropoid mandibles compared with prosimians would be associated with higher moments of inertia. From computed tomography scans, we estimated the scaling of the moment of inertia (I j ) of the mandibles of thirty-one species of primates, including 22 anthropoid and nine prosimian species, separating I j into the moment about a transverse axis through the center of mass (I xx ) and the moment of the center of mass about plausible axes of rotation. We found that across primates I j increases with positive allometry relative to jaw length, primarily due to positive allometry of jaw mass and I xx , and that anthropoid mandibles have greater rotational inertia compared with prosimian mandibles of similar length. Positive allometry of I j of primate mandibles actually lowers the predictive ability of the Spring Model, suggesting that scaling of primate chew cycle period, and chewing dynamics in general, are more strongly influenced by factors other than scaling of inertial properties of the mandible, such as the dynamic properties of the jaw muscles and neural control. Differences in cycle period scaling between chewing and locomotion
Inertia-confining thermonuclear molten salt reactors
International Nuclear Information System (INIS)
Furukawa, Kazuo; Yamanaka, Chiyoe; Nakai, Sadao; Imon, Shunji; Nakajima, Hidenori; Nakamura, Norio; Kato, Yoshio.
1984-01-01
Purpose: To increase the heat generating efficiency while improving the reactor safety and thereby maintaining the energy balance throughout the reactor. Constitution: In an inertia-confining type D-T thermonuclear reactor, the blanket is made of lithium-containing fluoride molten salts (LiF.BeF 2 , LiF.NaF.KF, LiF.KF, etc) which are cascaded downwardly in a large thickness (50 - 100 cm) along the inner wall of the thermonuclear reaction vessel, and neutrons generated by explosive compression are absorbed to lithium in the molten salts to produce tritium, Heat transportation is carried out by the molten salts. (Ikeda, J.)
On the moment of inertia of a quantum harmonic oscillator
International Nuclear Information System (INIS)
Khamzin, A. A.; Sitdikov, A. S.; Nikitin, A. S.; Roganov, D. A.
2013-01-01
An original method for calculating the moment of inertia of the collective rotation of a nucleus on the basis of the cranking model with the harmonic-oscillator Hamiltonian at arbitrary frequencies of rotation and finite temperature is proposed. In the adiabatic limit, an oscillating chemical-potential dependence of the moment of inertia is obtained by means of analytic calculations. The oscillations of the moment of inertia become more pronounced as deformations approach the spherical limit and decrease exponentially with increasing temperature.
Nuclear inertia for fission in a generalized cranking model
International Nuclear Information System (INIS)
Kunz, J.; Nix, J.R.
1984-01-01
A time dependent formalism which is appropriate for β vibrations and fission is developed for a generalized cranking model. The formalism leads to additional terms in the density matrix which affect the nuclear inertia. The case of a harmonic oscillator potential is used to demonstrate the contribution of the pairing gap term on the β vibrational inertia for Pu 240. The inertia remains finite and close to the limiting irrotational value
Moment of inertia and the interacting boson model
International Nuclear Information System (INIS)
Yoshida, N.; Sagawa, H.; Otsuka, T.; Arima, A.
1989-01-01
Mass-number dependence of the moment of inertia is studied in relation with the boson number in the SU(3) limit of the interacting boson model 1 (IBM-1). The analytic formula in the limit indicates the pairing correlation between nucleons is directly related to the moment of inertia in the IBM. It is shown in general that the kink of the moment of inertia coincides with the maximum boson number of each element. (author)
Nuclear moment of inertia and spin distribution of nuclear levels
International Nuclear Information System (INIS)
Alhassid, Y.; Fang, L.; Liu, S.; Bertsch, G.F.
2005-01-01
We introduce a simple model to calculate the nuclear moment of inertia at finite temperature. This moment of inertia describes the spin distribution of nuclear levels in the framework of the spin-cutoff model. Our model is based on a deformed single-particle Hamiltonian with pairing interaction and takes into account fluctuations in the pairing gap. We derive a formula for the moment of inertia at finite temperature that generalizes the Belyaev formula for zero temperature. We show that a number-parity projection explains the strong odd-even effects observed in shell model Monte Carlo studies of the nuclear moment of inertia in the iron region
Delamination detection in reinforced concrete using thermal inertia
International Nuclear Information System (INIS)
Del Grande, N K; Durbin, P F.
1998-01-01
We investigated the feasibility of thermal inertia mapping for bridge deck inspections. Using pulsed thermal imaging, we heat-stimulated surrogate delaminations in reinforced concrete and asphalt-concrete slabs. Using a dual-band infrared camera system, we measured thermal inertia responses of Styrofoam implants under 5 cm of asphalt, 5 cm of concrete, and 10 cm of asphalt and concrete. We compared thermal maps from solar-heated concrete and asphalt-concrete slabs with thermal inertia maps from flash-heated concrete and asphalt-concrete slabs. Thermal inertia mapping is a tool for visualizing and quantifying subsurface defects. Physically, thermal inertia is a measure of the resistance of the bridge deck to temperature change. Experimentally, it is determined from the inverse slope of the surface temperature versus the inverse square root of time. Mathematically, thermal inertia is the square root of the product of thermal conductivity, density, and heat capacity. Thermal inertia mapping distinguishes delaminated decks which have below-average thermal inertias from normal or shaded decks. Key Words: Pulsed Thermal Imaging, Thermal Inertia, Detection Of Concrete Bridgedeck Delaminations
Dynamics of Small Inertia-Free Spheroidal Particles in a Turbulent Channel Flow
Challabotla, Niranjan Reddy; Zhao, Lihao; Andersson, Helge I.; Department of Energy; Process Engineering Team
2015-11-01
The study of small non-spherical particles suspended in turbulent fluid flows is of interest in view of the potential applications in industry and the environment. In the present work, we investigated the dynamics of inertia-free spheroidal particles suspended in fully-developed turbulent channel flow at Re τ = 180 by using the direct numerical simulations (DNS) for the Eulerian fluid phase coupled with the Lagrangian point-particle tracking. We considered inertia-free spheroidal particles with a wide range of aspect ratios from 0.01 to 50, i.e. from flat disks to long rods. Although the spheroids passively translate along with the fluid, the particle orientation and rotation strongly depend on the particle shape. The flattest disks were preferentially aligned with their symmetry axis normal to the wall, whereas the longest rods aligned parallel to the wall. Strong mean rotational spin was observed for spherical particles and this has been damped with increasing asphericity both for rod-like and disk-like spheroids. The anisotropic mean and fluctuating fluid vorticity resulted in particle spin anisotropies which exhibited a complex dependence on the particle asphericty. The Research Council of Norway, Notur and COST Action FP1005 are gratefully acknowledged.
Directory of Open Access Journals (Sweden)
V. Comnac
2009-12-01
Full Text Available The paper presents sensorless state-space control of two-inertia drive system with resilient coupling. The control structure contains an I+PI controller for load speed regulation and a state feedback controller for effective vibration suppression of the elastic coupling. Mechanical state variable of two-inertia drive are obtained by using a linear minimum-order (Gopinath state observer. The design of the combined (I+PI and state feedback controller is achieved with the extended version of the modulus criterion [5]. The dynamic behavior of presented control structure has been examined, for different conditions, using MATLAB/SIMULINK simulation.
Viscous-elastic dynamics of power-law fluids within an elastic cylinder
Boyko, Evgeniy; Bercovici, Moran; Gat, Amir D.
2017-07-01
In a wide range of applications, microfluidic channels are implemented in soft substrates. In such configurations, where fluidic inertia and compressibility are negligible, the propagation of fluids in channels is governed by a balance between fluid viscosity and elasticity of the surrounding solid. The viscous-elastic interactions between elastic substrates and non-Newtonian fluids are particularly of interest due to the dependence of viscosity on the state of the system. In this work, we study the fluid-structure interaction dynamics between an incompressible non-Newtonian fluid and a slender linearly elastic cylinder under the creeping flow regime. Considering power-law fluids and applying the thin shell approximation for the elastic cylinder, we obtain a nonhomogeneous p-Laplacian equation governing the viscous-elastic dynamics. We present exact solutions for the pressure and deformation fields for various initial and boundary conditions for both shear-thinning and shear-thickening fluids. We show that in contrast to Stokes' problem where a compactly supported front is obtained for shear-thickening fluids, here the role of viscosity is inversed and such fronts are obtained for shear-thinning fluids. Furthermore, we demonstrate that for the case of a step in inlet pressure, the propagation rate of the front has a tn/n +1 dependence on time (t ), suggesting the ability to indirectly measure the power-law index (n ) of shear-thinning liquids through measurements of elastic deformation.
Transition from geostrophic turbulence to inertia-gravity waves in the atmospheric energy spectrum.
Callies, Jörn; Ferrari, Raffaele; Bühler, Oliver
2014-12-02
Midlatitude fluctuations of the atmospheric winds on scales of thousands of kilometers, the most energetic of such fluctuations, are strongly constrained by the Earth's rotation and the atmosphere's stratification. As a result of these constraints, the flow is quasi-2D and energy is trapped at large scales—nonlinear turbulent interactions transfer energy to larger scales, but not to smaller scales. Aircraft observations of wind and temperature near the tropopause indicate that fluctuations at horizontal scales smaller than about 500 km are more energetic than expected from these quasi-2D dynamics. We present an analysis of the observations that indicates that these smaller-scale motions are due to approximately linear inertia-gravity waves, contrary to recent claims that these scales are strongly turbulent. Specifically, the aircraft velocity and temperature measurements are separated into two components: one due to the quasi-2D dynamics and one due to linear inertia-gravity waves. Quasi-2D dynamics dominate at scales larger than 500 km; inertia-gravity waves dominate at scales smaller than 500 km.
Romero, Pilar; Barderas, Gonzalo; Mejuto, Javier
2018-05-01
We present a qualitative analysis in a phase space to determine the longitudinal equilibrium positions on the planetary stationary orbits by applying an analytical model that considers linear gravitational perturbations. We discuss how these longitudes are related with the orientation of the planetary principal inertia axes with respect to their Prime Meridians, and then we use this determination to derive their positions with respect to the International Celestial Reference Frame. Finally, a numerical analysis of the non-linear effects of the gravitational fields on the equilibrium point locations is developed and their correlation with gravity field anomalies shown.
Mars Surface Heterogeneity From Variations in Apparent Thermal Inertia
Putzig, N. E.; Mellon, M. T.
2005-12-01
Current techniques used in the calculation of thermal inertia from observed brightness temperatures typically assume that planetary surface properties are uniform on the scale of the instrument's observational footprint. Mixed or layered surfaces may yield different apparent thermal inertia values at different seasons or times of day due to the nonlinear relationship between temperature and thermal inertia. To obtain sufficient data coverage for investigating temporal changes, we processed three Mars years of observations from the Mars Global Surveyor Thermal Emission Spectrometer and produced seasonal nightside and dayside maps of apparent thermal inertia. These maps show broad regions with seasonal and diurnal differences as large as 200 J m-2 K-1 s-½ at mid-latitudes (60°S to 60°N) and ranging up to 600 J m-2 K-1 s-½ or greater in the polar regions. Comparison of the maps with preliminary results from forward-modeling of heterogeneous surfaces indicates that much of the martian surface may be dominated by (1) horizontally mixed surfaces, such as those containing differing proportions of rocks, sand, dust, duricrust, and localized frosts; (2) higher thermal inertia layers over lower thermal inertia substrates, such as duricrust or desert pavements; and (3) lower thermal inertia layers over higher thermal inertia substrates, such as dust over sand or rocks and soils with an ice table at depth.
Coupling diffusion and maximum entropy models to estimate thermal inertia
Thermal inertia is a physical property of soil at the land surface related to water content. We have developed a method for estimating soil thermal inertia using two daily measurements of surface temperature, to capture the diurnal range, and diurnal time series of net radiation and specific humidi...
Moments of Inertia of Disks and Spheres without Integration
Hong, Seok-Cheol; Hong, Seok-In
2013-01-01
Calculation of moments of inertia is often challenging for introductory-level physics students due to the use of integration, especially in non-Cartesian coordinates. Methods that do not employ calculus have been described for finding the rotational inertia of thin rods and other simple bodies. In this paper we use the parallel axis theorem and…
Moments of inertia in 162Yb at very high spins
International Nuclear Information System (INIS)
Simon, R.S.; Banaschik, M.V.; Colombani, P.; Soroka, D.P.; Stephens, F.S.; Diamond, R.M.
1976-01-01
Two methods have been used to obtain values of the effective moment of inertia of very-high-spin (20h-bar--50h-bar) states populated in heavy-ion compound-nucleus reactions. The 162 Yb nucleus studied has effective moments of inertia smaller than, but approaching, the rigid-body estimate
International Nuclear Information System (INIS)
Soares, J.M.D.
1984-01-01
This work study the resolution of Warren and X-trussed continuous beams using equivalent stiffness coefficients and moments of inertia. The equilibrium equations in the generic Joint r are obtained by finite differences method and the deflections and arbitrary static load equations are present in finite Fourier series form. The results of illustrative examples for both kinds of trussed be beams are compared with solutions obtained with the Lorane Linear Program. The influence of panels number and comparisions with classic result of equivalent inertia are established. Abacus for X-trussed beams for stiffness coefficients obtained by series versus equivalent inertia stiffness coefficients and corrections using the top and bottom chords area are presented. (Author) [pt
Rossi, Marcel M; Alderson, Jacqueline; El-Sallam, Amar; Dowling, James; Reinbolt, Jeffrey; Donnelly, Cyril J
2016-12-08
The aims of this study were to: (i) establish a new criterion method to validate inertia tensor estimates by setting the experimental angular velocity data of an airborne objects as ground truth against simulations run with the estimated tensors, and (ii) test the sensitivity of the simulations to changes in the inertia tensor components. A rigid steel cylinder was covered with reflective kinematic markers and projected through a calibrated motion capture volume. Simulations of the airborne motion were run with two models, using inertia tensor estimated with geometric formula or the compound pendulum technique. The deviation angles between experimental (ground truth) and simulated angular velocity vectors and the root mean squared deviation angle were computed for every simulation. Monte Carlo analyses were performed to assess the sensitivity of simulations to changes in magnitude of principal moments of inertia within ±10% and to changes in orientation of principal axes of inertia within ±10° (of the geometric-based inertia tensor). Root mean squared deviation angles ranged between 2.9° and 4.3° for the inertia tensor estimated geometrically, and between 11.7° and 15.2° for the compound pendulum values. Errors up to 10% in magnitude of principal moments of inertia yielded root mean squared deviation angles ranging between 3.2° and 6.6°, and between 5.5° and 7.9° when lumped with errors of 10° in principal axes of inertia orientation. The proposed technique can effectively validate inertia tensors from novel estimation methods of body segment inertial parameter. Principal axes of inertia orientation should not be neglected when modelling human/animal mechanics. Copyright © 2016 Elsevier Ltd. All rights reserved.
Indei, Tsutomu; Schieber, Jay D; Córdoba, Andrés
2012-04-01
We analyze the appropriate form for the generalized Stokes-Einstein relation (GSER) for viscoelastic solids and fluids when bead inertia and medium inertia are taken into account, which we call the inertial GSER. It was previously shown for Maxwell fluids that the Basset (or Boussinesq) force arising from medium inertia can act purely dissipatively at high frequencies, where elasticity of the medium is dominant. In order to elucidate the cause of this counterintuitive result, we consider Brownian motion in a purely elastic solid where ordinary Stokes-type dissipation is not possible. The fluctuation-dissipation theorem requires the presence of a dissipative mechanism for the particle to experience fluctuating Brownian forces in a purely elastic solid. We show that the mechanism for such dissipation arises from the radiation of elastic waves toward the system boundaries. The frictional force associated with this mechanism is the Basset force, and it exists only when medium inertia is taken into consideration in the analysis of such a system. We consider first a one-dimensional harmonic lattice where all terms in the generalized Langevin equation--i.e., the elastic term, the memory kernel, and Brownian forces-can be found analytically from projection-operator methods. We show that the dissipation is purely from radiation of elastic waves. A similar analysis is made on a particle in a continuum, three-dimensional purely elastic solid, where the memory kernel is determined from continuum mechanics. Again, dissipation arises only from radiation of elastic shear waves toward infinite boundaries when medium inertia is taken into account. If the medium is a viscoelastic solid, Stokes-type dissipation is possible in addition to radiational dissipation so that the wave decays at the penetration depth. Inertial motion of the bead couples with the elasticity of the viscoelastic material, resulting in a possible resonant oscillation of the mean-square displacement (MSD) of the
Development of inertia-increased reactor internal pump
International Nuclear Information System (INIS)
Tanaka, Masaaki; Matsumura, Seiichi; Kikushima, Jun; Kawamura, Shinichi; Yamashita, Norimichi; Kurosaki, Toshikazu; Kondo, Takahisa
2000-01-01
The Reactor Internal Pump (RIP) was adopted for the Reactor Recirculation System (RRS) of Advanced Boiling Water Reactor (ABWR) plants, and ten RIPs are located at the bottom of the reactor pressure vessel. In order to simplify the power supply system for the RIPs, a new inertia-increased RIP was developed, which allows to eliminate the Motor-Generator (M-G) sets. The rotating inertia was increased approximately 2.5 times of current RIP inertia by addition of flywheel on its main shaft. A full scale proving test of the inertia-increased RIP under actual plant operating conditions using full scale test loop was performed to evaluate vibration characteristics and coast down characteristics. From the results of this proving test, the validity of the new inertia-increased RIP and its power supply system (without M-G sets) was confirmed. (author)
Clinical inertia, uncertainty and individualized guidelines.
Reach, G
2014-09-01
Doctors often do not follow the guidelines of good practice based on evidence-based medicine, and this "clinical inertia" may represent an impediment to efficient care. The aims of this article are as follows: 1) to demonstrate that this phenomenon is often the consequence of a discrepancy between the technical rationality of evidence-based medicine and the modes of reasoning of physicians practiced in "real-life", which is marked by uncertainty and risk; 2) to investigate in this context the meaning of the recent, somewhat paradoxical, concept of "individualized guidelines"; and 3) to revisit the real, essentially pedagogical, place of guidelines in medical practice. Copyright © 2014. Published by Elsevier Masson SAS.
Kanady, Jennifer C; Harvey, Allison G
2015-10-01
Sleep inertia is the transitional state from sleep to wake. Research on sleep inertia is important in depression because many people with depression report having difficulty getting out of bed, which contributes to impairment and can impede the implementation of interventions. The first aim was to develop and validate the first self-report measure of sleep inertia, the Sleep Inertia Questionnaire (SIQ). The second aim was to compare reports of sleep inertia across three groups: (1) No-to-Mild-Depression, (2) Analogue-Depression, and (3) Syndromal-Depression. The SIQ demonstrates strong psychometric properties; it has good to excellent internal consistency, strong construct validity, and SIQ severity is associated with less prior sleep duration. Sleep inertia is more severe in the Analogue-Depression and Syndromal-Depression groups compared to the No-to-Mild-Depression group. In conclusion, the SIQ is a reliable measure of sleep inertia and has potential for improving the assessment of sleep inertia in clinical and research settings.
Therapeutic inertia amongst general practitioners with interest in diabetes.
Seidu, Samuel; Than, Tun; Kar, Deb; Lamba, Amrit; Brown, Pam; Zafar, Azhar; Hussain, Rizwan; Amjad, Ahmed; Capehorn, Mathew; Martin, Elizabeth; Fernando, Kevin; McMoran, Jim; Millar-Jones, David; Kahn, Shahzada; Campbell, Nigel; Brice, Richard; Mohan, Rahul; Mistry, Mukesh; Kanumilli, Naresh; St John, Joan; Quigley, Richard; Kenny, Colin; Khunti, Kamlesh
2018-02-01
As the therapeutic options in the management of type 2 diabetes increase, there is an increase confusion among health care professionals, thus leading to the phenomenon of therapeutic inertia. This is the failure to escalate or de-escalate treatment when the clinical need for this is required. It has been studied extensively in various settings, however, it has never been reported in any studies focusing solely on primary care physicians with an interest in diabetes. This group is increasingly becoming the focus of managing complex diabetes care in the community, albeit with the support from specialists. In this retrospective audit, we assessed the prevalence of the phenomenon of therapeutic inertia amongst primary care physicians with an interest in diabetes in UK. We also assessed the predictive abilities of various patient level characteristics on therapeutic inertia amongst this group of clinicians. Out of the 240 patients reported on, therapeutic inertia was judged to have occurred in 53 (22.1%) of patients. The full model containing all the selected variables was not statistically significant, p=0.59. So the model was not able to distinguish between situations in which therapeutic inertia occurred and when it did not occur. None of the patient level characteristics on its own was predictive of therapeutic inertia. Therapeutic inertia was present only in about a fifth of patient patients with diabetes being managed by primary care physicians with an interest in diabetes. Copyright © 2017 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.
Selective effects of weight and inertia on maximum lifting.
Leontijevic, B; Pazin, N; Kukolj, M; Ugarkovic, D; Jaric, S
2013-03-01
A novel loading method (loading ranged from 20% to 80% of 1RM) was applied to explore the selective effects of externally added simulated weight (exerted by stretched rubber bands pulling downward), weight+inertia (external weights added), and inertia (covariation of the weights and the rubber bands pulling upward) on maximum bench press throws. 14 skilled participants revealed a load associated decrease in peak velocity that was the least associated with an increase in weight (42%) and the most associated with weight+inertia (66%). However, the peak lifting force increased markedly with an increase in both weight (151%) and weight+inertia (160%), but not with inertia (13%). As a consequence, the peak power output increased most with weight (59%), weight+inertia revealed a maximum at intermediate loads (23%), while inertia was associated with a gradual decrease in the peak power output (42%). The obtained findings could be of importance for our understanding of mechanical properties of human muscular system when acting against different types of external resistance. Regarding the possible application in standard athletic training and rehabilitation procedures, the results speak in favor of applying extended elastic bands which provide higher movement velocity and muscle power output than the usually applied weights. © Georg Thieme Verlag KG Stuttgart · New York.
Emotional inertia contributes to depressive symptoms beyond perseverative thinking.
Brose, Annette; Schmiedek, Florian; Koval, Peter; Kuppens, Peter
2015-01-01
The autocorrelation or inertia of negative affect reflects how much negative emotions carry over from moment to moment and has been associated with increased depressive symptoms. In this study, we posed three challenges to this association by examining: (1) whether emotional inertia is relevant for depressive symptoms when assessed on a longer timescale than usual; (2) whether inertia is uniquely related to depressive symptoms after controlling for perseverative thoughts; and (3) whether inertia is related to depressive symptoms over and above the within-person association between affect and perseverative thoughts. Participants (N = 101) provided ratings of affect and perseverative thoughts for 100 days; depressive symptoms were reported before and after the study, and again after 2.5 years. Day-to-day emotional inertia was related to depressive symptoms over and above trait and state perseverative thoughts. Moreover, inertia predicted depressive symptoms when adjusting for its association with perseverative thoughts. These findings establish the relevance of emotional inertia in depressive symptoms independent of perseverative thoughts.
The cranking moment of inertia in a static potential
International Nuclear Information System (INIS)
Bengtsson, R.; Hamamoto, I.; Ibarra, R.H.
1978-01-01
Taking into account the self-consistency condition for the deformation, the authors estimate the cranking moment of inertia in the absence of pair-correlations for the Woods-Saxon potential and various versions of the modified oscillator potential. The authors investigate the expectation that in a static potential the moment of inertia is almost equal to the rigid-body moment of inertia at the self-consistent deformation. They examine especially the consequence of the presence of the l 2 term in the conventional modified oscillator potential. (Auth.)
Moments of inertia for solids of revolution and variational methods
International Nuclear Information System (INIS)
Diaz, Rodolfo A; Herrera, William J; Martinez, R
2006-01-01
We present some formulae for the moments of inertia of homogeneous solids of revolution in terms of the functions that generate the solids. The development of these expressions exploits the cylindrical symmetry of these objects and avoids the explicit use of multiple integration, providing an easy and pedagogical approach. The explicit use of the functions that generate the solid gives the possibility of writing the moment of inertia as a functional, which in turn allows us to utilize the calculus of variations to obtain new insight into some properties of this fundamental quantity. In particular, minimization of moments of inertia under certain restrictions is possible by using variational methods
Angular Momentum Transfer and Fractional Moment of Inertia in Pulsar Glitches
International Nuclear Information System (INIS)
Eya, I. O.; Urama, J. O.; Chukwude, A. E.
2017-01-01
We use the Jodrell Bank Observatory glitch database containing 472 glitches from 165 pulsars to investigate the angular momentum transfer during rotational glitches in pulsars. Our emphasis is on pulsars with at least five glitches, of which there are 26 that exhibit 261 glitches in total. This paper identifies four pulsars in which the angular momentum transfer, after many glitches, is almost linear with time. The Lilliefore test on the cumulative distribution of glitch spin-up sizes in these glitching pulsars shows that glitch sizes in 12 pulsars are normally distributed, suggesting that their glitches originate from the same momentum reservoir. In addition, the distribution of the fractional moment of inertia (i.e., the ratio of the moment of inertia of neutron star components that are involved in the glitch process) have a single mode, unlike the distribution of fractional glitch size (Δ ν / ν ), which is usually bimodal. The mean fractional moment of inertia in the glitching pulsars we sampled has a very weak correlation with the pulsar spin properties, thereby supporting a neutron star interior mechanism for the glitch phenomenon.
Angular Momentum Transfer and Fractional Moment of Inertia in Pulsar Glitches
Energy Technology Data Exchange (ETDEWEB)
Eya, I. O.; Urama, J. O.; Chukwude, A. E., E-mail: innocent.eya@unn.edu.ng, E-mail: innocent.eya@gmail.com [Department of Physics and Astronomy, University of Nigeria, Nsukka, Enugu State (Nigeria)
2017-05-01
We use the Jodrell Bank Observatory glitch database containing 472 glitches from 165 pulsars to investigate the angular momentum transfer during rotational glitches in pulsars. Our emphasis is on pulsars with at least five glitches, of which there are 26 that exhibit 261 glitches in total. This paper identifies four pulsars in which the angular momentum transfer, after many glitches, is almost linear with time. The Lilliefore test on the cumulative distribution of glitch spin-up sizes in these glitching pulsars shows that glitch sizes in 12 pulsars are normally distributed, suggesting that their glitches originate from the same momentum reservoir. In addition, the distribution of the fractional moment of inertia (i.e., the ratio of the moment of inertia of neutron star components that are involved in the glitch process) have a single mode, unlike the distribution of fractional glitch size (Δ ν / ν ), which is usually bimodal. The mean fractional moment of inertia in the glitching pulsars we sampled has a very weak correlation with the pulsar spin properties, thereby supporting a neutron star interior mechanism for the glitch phenomenon.
Medicaid program choice, inertia and adverse selection.
Marton, James; Yelowitz, Aaron; Talbert, Jeffery C
2017-12-01
In 2012, Kentucky implemented Medicaid managed care statewide, auto-assigned enrollees to three plans, and allowed switching. Using administrative data, we find that the state's auto-assignment algorithm most heavily weighted cost-minimization and plan balancing, and placed little weight on the quality of the enrollee-plan match. Immobility - apparently driven by health plan inertia - contributed to the success of the cost-minimization strategy, as more than half of enrollees auto-assigned to even the lowest quality plans did not opt-out. High-cost enrollees were more likely to opt-out of their auto-assigned plan, creating adverse selection. The plan with arguably the highest quality incurred the largest initial profit margin reduction due to adverse selection prior to risk adjustment, as it attracted a disproportionate share of high-cost enrollees. The presence of such selection, caused by differential degrees of mobility, raises concerns about the long run viability of the Medicaid managed care market without such risk adjustment. Copyright © 2017 Elsevier B.V. All rights reserved.
The effect of inertia, viscous damping, temperature and normal ...
Indian Academy of Sciences (India)
Nitish Sinha
2018-04-16
Apr 16, 2018 ... physical parameters such as inertia, viscous damping, temperature and normal stress on the chaotic ... However, the present study has shown the appearance of chaos for the specific .... Although chaos is a general man-.
Einstein's equivalence principle instead of the inertia forces
International Nuclear Information System (INIS)
Herreros Mateos, F.
1997-01-01
In this article I intend to show that Einstein's equivalence principle substitutes advantageously the inertia forces in the study and resolution of problems in which non-inertial systems appear. (Author) 13 refs
On the moment of inertia of a proto neutron star
International Nuclear Information System (INIS)
Zhao Xianfeng; Zhang Hua; Jia Huanyu
2010-01-01
The influences of σ * and Φ mesons,temperature and coupling constants of nucleons on the moment of inertia of the proto neutron star (PNS) are examined in the framework of relativistic mean field theory for the baryon octet {n, p, Λ , Σ - , Σ 0 , Σ + , Ξ - , Ξ 0 } system. It is found that, compared with that without considering σ * and Φ mesons, the moment of inertia decreases. It is also found that the higher the temperature, the larger the incompressibility and symmetry energy coefficient, and the larger the moment of inertia of a PNS. The influence of temperature and coupling constants of the nucleons on the moment of inertia of a PNS is larger than that of the σ * and Φ mesons. (authors)
A new inertia weight control strategy for particle swarm optimization
Zhu, Xianming; Wang, Hongbo
2018-04-01
Particle Swarm Optimization is a member of swarm intelligence algorithms, which is inspired by the behavior of bird flocks. The inertia weight, one of the most important parameters of PSO, is crucial for PSO, for it balances the performance of exploration and exploitation of the algorithm. This paper proposes a new inertia weight control strategy and PSO with this new strategy is tested by four benchmark functions. The results shows that the new strategy provides the PSO with better performance.
Pairing field and moments of inertia of superdeformed nuclei
International Nuclear Information System (INIS)
Chen Yongjing; Chen Yongshou; Xu Fuxin
2002-01-01
The authors have systematically analysed the dynamic moments of inertia of the experimental superdeformed (SD) bands observed in the A = 190, 150 and 60-80 mass regions as functions of rotational frequency. By combining the different mass regions, the dramatic features of the dynamic moments of inertia were found and explained based on the calculations of the pairing fields of SD nuclei with the anisotropic harmonic oscillator quadrupole pairing Hartree-Fock-Bogoliubov model
The role of resonance in propulsion of an elastic pitching wing with or without inertia
Zhang, Yang; Zhou, Chunhua; Luo, Haoxiang; Luo Team; Zhou Team
2016-11-01
Flapping wings of insects and undulating fins of fish both experience significant elastic deformations during propulsion, and it has been shown that in both cases, the deformations are beneficial to force enhancement and power efficiency. In fish swimming, the inertia of the fin structure is negligible and the hydrodynamic force is solely responsible for the deformation. However, in insect flight, both the wing inertia and aerodynamic force can be important factors leading to wing deformation. This difference raises the question about the role of the system (fluid-structure) resonance in the performance of propulsion. In this study, we use a 2D pitching foil as a model wing and vary its bending rigidity, pitching frequency, and mass ratio to investigate the fluid-structure interaction near resonance. The results show that at low mass ratios, i.e., a scenario of swimming, the system resonance greatly enhances thrust production and power efficiency, which is consistent with previous experimental results. However, at high mass ratios, i.e., a scenario of flying, the system resonance leads to overly large deformation that actually does not bring benefit any more. This conclusion thus suggests that resonance plays different roles in flying and in swimming. Supported by the NNSF of China and the NSF of US.
Effects of microscale inertia on dynamic ductile crack growth
Jacques, N.; Mercier, S.; Molinari, A.
2012-04-01
The aim of this paper is to investigate the role of microscale inertia in dynamic ductile crack growth. A constitutive model for porous solids that accounts for dynamic effects due to void growth is proposed. The model has been implemented in a finite element code and simulations of crack growth in a notched bar and in an edge cracked specimen have been performed. Results are compared to predictions obtained via the Gurson-Tvergaard-Needleman (GTN) model where micro-inertia effects are not accounted for. It is found that microscale inertia has a significant influence on the crack growth. In particular, it is shown that micro-inertia plays an important role during the strain localisation process by impeding void growth. Therefore, the resulting damage accumulation occurs in a more progressive manner. For this reason, simulations based on the proposed modelling exhibit much less mesh sensitivity than those based on the viscoplastic GTN model. Microscale inertia is also found to lead to lower crack speeds. Effects of micro-inertia on fracture toughness are evaluated.
Effects of moment of inertia on restricted motion swing speed.
Schorah, David; Choppin, Simon; James, David
2015-06-01
In many sports, the maximum swing speed of a racket, club, or bat is a key performance parameter. Previous research in multiple sports supports the hypothesis of an inverse association between the swing speed and moment of inertia of an implement. The aim of this study was to rigorously test and quantify this relationship using a restricted swinging motion. Eight visually identical rods with a common mass but variable moment of inertia were manufactured. Motion capture technology was used to record eight participants' maximal effort swings with the rods. Strict exclusion criteria were applied to data that did not adhere to the prescribed movement pattern. The study found that for all participants, swing speed decreased with respect to moment of inertia according to a power relationship. However, in contrast to previous studies, the rate of decrease varied from participant to participant. With further analysis it was found that participants performed more consistently at the higher end of the moment of inertia range tested. The results support the inverse association between swing speed and moment of inertia but only for higher moment of inertia implements.
Development of an Inertia-Increased ABWR Internal Pump
International Nuclear Information System (INIS)
Shirou Takahashi; Kousei Umemori; Kooji Shiina; Tetsuya Totani; Akihiro Sakashita; Norimichi Yamashita; Takahisa Kondo
2002-01-01
It is possible to simplify the reactor internal pump power supply system in the ABWR without affecting the core flow supply when a trip of all RIPs event occurs by eliminating the motor-generator sets and increasing the rotating inertia of the RIPs. This inertia increase due to an additional flywheel, which leads to a gain in weight and length, requires a larger diameter nozzle with a thicker sleeve. However, a thicker sleeve nozzle and a longer and heavier motor casing may change the RIP performance. In the present study, the inertia-increased RIP was verified through full-scale tests. The rotating inertia time constant for coast-down characteristics (behavior of the RIP speed in the event of power loss) for the inertia-increased RIP was doubled compared with the current RIP. The inertia-increased RIP with the thicker sleeve nozzle maintained good performance and its power supply system without motor-generator sets was judged appropriate for the ABWR. (authors)
Compensations for increased rotational inertia during human cutting turns.
Qiao, Mu; Brown, Brian; Jindrich, Devin L
2014-02-01
Locomotion in a complex environment is often not steady state, but unsteady locomotion (stability and maneuverability) is not well understood. We investigated the strategies used by humans to perform sidestep cutting turns when running. Previous studies have argued that because humans have small yaw rotational moments of inertia relative to body mass, deceleratory forces in the initial velocity direction that occur during the turning step, or 'braking' forces, could function to prevent body over-rotation during turns. We tested this hypothesis by increasing body rotational inertia and testing whether braking forces during stance decreased. We recorded ground reaction force and body kinematics from seven participants performing 45 deg sidestep cutting turns and straight running at five levels of body rotational inertia, with increases up to fourfold. Contrary to our prediction, braking forces remained consistent at different rotational inertias, facilitated by anticipatory changes to body rotational speed. Increasing inertia revealed that the opposing effects of several turning parameters, including rotation due to symmetrical anterior-posterior forces, result in a system that can compensate for fourfold changes in rotational inertia with less than 50% changes to rotational velocity. These results suggest that in submaximal effort turning, legged systems may be robust to changes in morphological parameters, and that compensations can involve relatively minor adjustments between steps to change initial stance conditions.
Neural predictors of emotional inertia in daily life.
Waugh, Christian E; Shing, Elaine Z; Avery, Bradley M; Jung, Youngkyoo; Whitlow, Christopher T; Maldjian, Joseph A
2017-09-01
Assessing emotional dynamics in the brain offers insight into the fundamental neural and psychological mechanisms underlying emotion. One such dynamic is emotional inertia-the influence of one's emotional state at one time point on one's emotional state at a subsequent time point. Emotion inertia reflects emotional rigidity and poor emotion regulation as evidenced by its relationship to depression and neuroticism. In this study, we assessed changes in cerebral blood flow (CBF) from before to after an emotional task and used these changes to predict stress, positive and negative emotional inertia in daily life events. Cerebral blood flow changes in the lateral prefrontal cortex (lPFC) predicted decreased non-specific emotional inertia, suggesting that the lPFC may feature a general inhibitory mechanism responsible for limiting the impact that an emotional state from one event has on the emotional state of a subsequent event. CBF changes in the ventromedial prefrontal cortex and lateral occipital cortex were associated with positive emotional inertia and negative/stress inertia, respectively. These data advance the blossoming literature on the temporal dynamics of emotion in the brain and on the use of neural indices to predict mental health-relevant behavior in daily life. © The Author (2017). Published by Oxford University Press.
Lázaro, Pablo; Murga, Nekane; Aguilar, Dolores; Hernández-Presa, Miguel A
2010-12-01
Studies indicate that dyslipidemia is undertreated. Numerous systematic reviews have shown that, even when therapeutic targets set by clinical practice guidelines have not been met, treatment remains unchanged despite the availability of alternatives approaches. The result is increased morbidity and mortality. Our aims were to investigate this phenomenon, known as therapeutic inertia, in patients with dyslipidemia and ischemic heart disease, and to determine its possible causes. national, multicenter, observational study of data obtained from physicians by questionnaire and from the clinical records of patients with ischemic heart disease. Main variable: therapeutic inertia during a consultation, defined as treatment remaining the same despite a change being indicated (e.g. low-density lipoprotein cholesterol >100 mg/dl or >70 mg/dl in diabetics). Covariates: physician, patient and consultation characteristics. multivariate logistic regression analysis of factors associated with therapeutic inertia during a consultation. Overall, 43% of consultations involved therapeutic inertia, and an association with coronary risk factors, including diabetes, did not result in a change in treatment. Therapeutic inertia occurred more frequently when there was a long time between the diagnosis and treatment of dyslipidemia and that of ischemic heart disease. Undertreatment was particularly common in women despite a greater overall risk. The more experienced physicians treated younger patients more appropriately. Clinical practice was improved by educational sessions at conferences. Therapeutic inertia was common in patients with chronic ischemic heart disease and dyslipidemia, irrespective of overall cardiovascular risk. Factors associated with the patient, disease and physician had an influence.
Huang, Li-Ying; Shau, Wen-Yi; Yeh, Hseng-Long; Chen, Tsung-Tai; Hsieh, Jun Yi; Su, Syi; Lai, Mei-Shu
2015-01-01
This article presents an analysis conducted on the patterns related to therapeutic inertia with the aim of uncovering how variables at the patient level and the healthcare provider level influence the intensification of therapy when it is clinically indicated. A cohort study was conducted on 899,135 HbA1c results from 168,876 adult diabetes patients with poorly controlled HbA1c levels. HbA1c results were used to identify variations in the prescription of hypoglycemic drugs. Logistic regression and hierarchical linear models (HLMs) were used to determine how differences among healthcare providers and patient characteristics influence therapeutic inertia. We estimated that 38.5% of the patients in this study were subject to therapeutic inertia. The odds ratio of cardiologists choosing to intensify therapy was 0.708 times that of endocrinologists. Furthermore, patients in medical centers were shown to be 1.077 times more likely to be prescribed intensified treatment than patients in primary clinics. The HLMs presented results similar to those of the logistic model. Overall, we determined that 88.92% of the variation in the application of intensified treatment was at the within-physician level. Reducing therapeutic inertia will likely require educational initiatives aimed at ensuring adherence to clinical practice guidelines in the care of diabetes patients. © 2014, The American College of Clinical Pharmacology.
Apparent thermal inertia and the surface heterogeneity of Mars
Putzig, Nathaniel E.; Mellon, Michael T.
2007-11-01
Thermal inertia derivation techniques generally assume that surface properties are uniform at horizontal scales below the footprint of the observing instrument and to depths of several decimeters. Consequently, surfaces with horizontal or vertical heterogeneity may yield apparent thermal inertia which varies with time of day and season. To investigate these temporal variations, we processed three Mars years of Mars Global Surveyor Thermal Emission Spectrometer observations and produced global nightside and dayside seasonal maps of apparent thermal inertia. These maps show broad regions with diurnal and seasonal differences up to 200 J m -2 K -1s -1/2 at mid-latitudes (60° S to 60° N) and 600 J m -2 K -1s -1/2 or greater in the polar regions. We compared the seasonal mapping results with modeled apparent thermal inertia and created new maps of surface heterogeneity at 5° resolution, delineating regions that have thermal characteristics consistent with horizontal mixtures or layers of two materials. The thermal behavior of most regions on Mars appears to be dominated by layering, with upper layers of higher thermal inertia (e.g., duricrusts or desert pavements over fines) prevailing in mid-latitudes and upper layers of lower thermal inertia (e.g., dust-covered rock, soils with an ice table at shallow depths) prevailing in polar regions. Less common are regions dominated by horizontal mixtures, such as those containing differing proportions of rocks, sand, dust, and duricrust or surfaces with divergent local slopes. Other regions show thermal behavior that is more complex and not well-represented by two-component surface models. These results have important implications for Mars surface geology, climate modeling, landing-site selection, and other endeavors that employ thermal inertia as a tool for characterizing surface properties.
A Novel Flexible Inertia Weight Particle Swarm Optimization Algorithm
Shamsi, Mousa; Sedaaghi, Mohammad Hossein
2016-01-01
Particle swarm optimization (PSO) is an evolutionary computing method based on intelligent collective behavior of some animals. It is easy to implement and there are few parameters to adjust. The performance of PSO algorithm depends greatly on the appropriate parameter selection strategies for fine tuning its parameters. Inertia weight (IW) is one of PSO’s parameters used to bring about a balance between the exploration and exploitation characteristics of PSO. This paper proposes a new nonlinear strategy for selecting inertia weight which is named Flexible Exponential Inertia Weight (FEIW) strategy because according to each problem we can construct an increasing or decreasing inertia weight strategy with suitable parameters selection. The efficacy and efficiency of PSO algorithm with FEIW strategy (FEPSO) is validated on a suite of benchmark problems with different dimensions. Also FEIW is compared with best time-varying, adaptive, constant and random inertia weights. Experimental results and statistical analysis prove that FEIW improves the search performance in terms of solution quality as well as convergence rate. PMID:27560945
Observing the variation of asteroid thermal inertia with heliocentric distance
Rozitis, B.; Green, S. F.; MacLennan, E.; Emery, J. P.
2018-06-01
Thermal inertia is a useful property to characterize a planetary surface, since it can be used as a qualitative measure of the regolith grain size. It is expected to vary with heliocentric distance because of its dependence on temperature. However, no previous investigation has conclusively observed a change in thermal inertia for any given planetary body. We have addressed this by using NEOWISE data and the Advanced Thermophysical Model to study the thermophysical properties of the near-Earth asteroids (1036) Ganymed, (1580) Betulia, and (276 049) 2002 CE26 as they moved around their highly eccentric orbits. We confirm that the thermal inertia values of Ganymed and 2002 CE26 do vary with heliocentric distance, although the degree of variation observed depends on the spectral emissivity assumed in the thermophysical modelling. We also confirm that the thermal inertia of Betulia did not change for three different observations obtained at the same heliocentric distance. Depending on the spectral emissivity, the variations for Ganymed and 2002 CE26 are potentially more extreme than that implied by theoretical models of heat transfer within asteroidal regoliths, which might be explained by asteroids having thermal properties that also vary with depth. Accounting for this variation reduces a previously observed trend of decreasing asteroid thermal inertia with increasing size, and suggests that the surfaces of small and large asteroids could be much more similar than previously thought. Furthermore, this variation can affect Yarkovsky orbital drift predictions by a few tens of per cent.
Inertia in nursing care of hospitalised patients with urinary incontinence.
Artero-López, Consuelo; Márquez-Hernández, Verónica V; Estevez-Morales, María Teresa; Granados-Gámez, Genoveva
2018-04-01
To assess the existence of therapeutic inertia in the nursing care of patients with urinary incontinence during the patient's time in hospital, together with the sociodemographic and professional variables involved. Inertia in care is a problem which appears in the nursing care process. Actions related to inertia can be attributed to not adhering to protocols, clinical guidelines and the lack of prevention measures which have undesirable effects on the efficiency of care. This was a prospective observational study. A total of 132 nursing professionals participated over two consecutive months. Data were collected randomly through the method of systematic, nonparticipative observation of medical practice units and patients' medical records. The results showed a pattern of severely compromised action in the assessment of the pattern of urinary elimination, in actions related to urinary continence, in therapeutic behaviour and in patient satisfaction and were found to be consistent with professional experience (p inertia exists in nursing care in the hospital environment while the patient is hospitalised, in prevention care, in the treatment of urinary incontinence and in the management of records. Contributing to the understanding of the existence of inertia in nursing care raises questions regarding its causes and interventions to predict or monitor it. © 2018 John Wiley & Sons Ltd.
Inertia and Double Bending of Light from Equivalence
Shuler, Robert L., Jr.
2010-01-01
Careful examination of light paths in an accelerated reference frame, with use of Special Relativity, can account fully for the observed bending of light in a gravitational field, not just half of it as reported in 1911. This analysis also leads to a Machian formulation of inertia similar to the one proposed by Einstein in 1912 and later derived from gravitational field equations in Minkowsky Space by Sciama in 1953. There is a clear inference from equivalence that there is some type of inertial mass increase in a gravitational field. It is the purpose of the current paper to suggest that equivalence provides a more complete picture of gravitational effects than previously thought, correctly predicting full light bending, and that since the theory of inertia is derivable from equivalence, any theory based on equivalence must take account of it. Einstein himself clearly was not satisfied with the status of inertia in GRT, as our quotes have shown. Many have tried to account for inertia and met with less than success, for example Davidson s integration of Sciama s inertia into GRT but only for a steady state cosmology [10], and the Machian gravity theory of Brans and Dicke [11]. Yet Mach s idea hasn t gone away, and now it seems that it cannot go away without also disposing of equivalence.
A Novel Flexible Inertia Weight Particle Swarm Optimization Algorithm.
Amoshahy, Mohammad Javad; Shamsi, Mousa; Sedaaghi, Mohammad Hossein
2016-01-01
Particle swarm optimization (PSO) is an evolutionary computing method based on intelligent collective behavior of some animals. It is easy to implement and there are few parameters to adjust. The performance of PSO algorithm depends greatly on the appropriate parameter selection strategies for fine tuning its parameters. Inertia weight (IW) is one of PSO's parameters used to bring about a balance between the exploration and exploitation characteristics of PSO. This paper proposes a new nonlinear strategy for selecting inertia weight which is named Flexible Exponential Inertia Weight (FEIW) strategy because according to each problem we can construct an increasing or decreasing inertia weight strategy with suitable parameters selection. The efficacy and efficiency of PSO algorithm with FEIW strategy (FEPSO) is validated on a suite of benchmark problems with different dimensions. Also FEIW is compared with best time-varying, adaptive, constant and random inertia weights. Experimental results and statistical analysis prove that FEIW improves the search performance in terms of solution quality as well as convergence rate.
Sina, Nima; Moosavi, Hassan; Aghaei, Hosein; Afrand, Masoud; Wongwises, Somchai
2017-01-01
In this paper, for the first time, a nonlocal Timoshenko beam model is employed for studying the wave dispersion of a fluid-conveying single-walled carbon nanotube on Viscoelastic Pasternak foundation under high and low temperature change. In addition, the phase and group velocity for the nanotube are discussed, respectively. The influences of Winkler and Pasternak modulus, homogenous temperature change, steady flow velocity and damping factor of viscoelastic foundation on wave dispersion of carbon nanotubes are investigated. It was observed that the characteristic of the wave for carbon nanotubes conveying fluid is the normal dispersion. Moreover, implying viscoelastic foundation leads to increasing the wave frequencies.
International Nuclear Information System (INIS)
Wang, Liang; Germaschewski, K.; Hakim, Ammar H.; Bhattacharjee, A.
2015-01-01
We introduce an extensible multi-fluid moment model in the context of collisionless magnetic reconnection. This model evolves full Maxwell equations and simultaneously moments of the Vlasov-Maxwell equation for each species in the plasma. Effects like electron inertia and pressure gradient are self-consistently embedded in the resulting multi-fluid moment equations, without the need to explicitly solving a generalized Ohm's law. Two limits of the multi-fluid moment model are discussed, namely, the five-moment limit that evolves a scalar pressures for each species and the ten-moment limit that evolves the full anisotropic, non-gyrotropic pressure tensor for each species. We first demonstrate analytically and numerically that the five-moment model reduces to the widely used Hall magnetohydrodynamics (Hall MHD) model under the assumptions of vanishing electron inertia, infinite speed of light, and quasi-neutrality. Then, we compare ten-moment and fully kinetic particle-in-cell (PIC) simulations of a large scale Harris sheet reconnection problem, where the ten-moment equations are closed with a local linear collisionless approximation for the heat flux. The ten-moment simulation gives reasonable agreement with the PIC results regarding the structures and magnitudes of the electron flows, the polarities and magnitudes of elements of the electron pressure tensor, and the decomposition of the generalized Ohm's law. Possible ways to improve the simple local closure towards a nonlocal fully three-dimensional closure are also discussed
Inertia of rough and vicinal surfaces of helium-4 crystals
International Nuclear Information System (INIS)
Amrit, J.; Legros, P.; Poitrenaud, J.
1995-01-01
This paper reports a study of the inertia of rough and vicinal of 4 He crystals. We have measured the transmission coefficient of ultrasonic waves at frequencies 10, 30, 50 and 70 MHz, across the liquid-solid interface. The experiments are carried out at temperatures ranging between 0.4 and 1.0 K for four crystallographic orientations. Two important phenomena are put to evidence for the first time. We have found the first experimental evidence that the inertia of rough surfaces depends on temperature. For vicinal surfaces, we have shown the strong increase of the inertia as the tilt angle decreases. Our experimental results agree very well with the theoretical predictions
Temperature-dependent particle-number projected moment of inertia
International Nuclear Information System (INIS)
Allal, N. H.; Fellah, M.; Benhamouda, N.; Oudih, M. R.
2008-01-01
Expressions of the parallel and perpendicular temperature-dependent particle-number projected nuclear moment of inertia have been established by means of a discrete projection method. They generalize that of the FTBCS method and are well adapted to numerical computation. The effects of particle-number fluctuations have been numerically studied for some even-even actinide nuclei by using the single-particle energies and eigenstates of a deformed Woods-Saxon mean field. It has been shown that the parallel moment of inertia is practically not modified by the use of the projection method. In contrast, the discrepancy between the projected and FTBCS perpendicular moment of inertia values may reach 5%. Moreover, the particle-number fluctuation effects vary not only as a function of the temperature but also as a function of the deformation for a given temperature. This is not the case for the system energy
Factors associated with clinical inertia: an integrative review
Aujoulat, Isabelle; Jacquemin, Patricia; Rietzschel, Ernst; Scheen, André; Tréfois, Patrick; Wens, Johan; Darras, Elisabeth; Hermans, Michel P
2014-01-01
Failure to initiate or intensify therapy according to evidence-based guidelines is increasingly being acknowledged as a phenomenon that contributes to inadequate management of chronic conditions, and is referred to as clinical inertia. However, the number and complexity of factors associated with the clinical reasoning that underlies the decision-making processes in medicine calls for a critical examination of the consistency of the concept. Indeed, in the absence of information on and justification of treatment decisions that were made, clinical inertia may be only apparent, and actually reflect good clinical practice. This integrative review seeks to address the factors generally associated with clinical inaction, in order to better delineate the concept of true clinical inertia. PMID:24868181
Reduction of nuclear moment of inertia due to pairing interaction
International Nuclear Information System (INIS)
Zeng, J.Y.; Jin, T.H.; Zhao, Z.J.
1994-01-01
The BCS theoretical values of the moments of inertia of even-even nuclei are systematically smaller than the experimental ones by a factor of 10--40%. This long-standing discrepancy disappears in the particle-number-conserving treatment for the cranked shell model, in which the blocking effects are taken into account exactly. The calculated moments of inertia satisfactorily reproduce the experimental data covering a large number of rare-earth even-even nuclei, whose deformations and single-particle states are well characterized (Lund systematics). The pairing interaction strength G is unambiguously determined by the even-odd mass difference. The reduction of the moment of inertia due to the antialignment effect of pairing interaction is discussed and no systematic excessive reduction is found
Electron inertia effects on the planar plasma sheath problem
International Nuclear Information System (INIS)
Duarte, V. N.; Clemente, R. A.
2011-01-01
The steady one-dimensional planar plasma sheath problem, originally considered by Tonks and Langmuir, is revisited. Assuming continuously generated free-falling ions and isothermal electrons and taking into account electron inertia, it is possible to describe the problem in terms of three coupled integro-differential equations that can be numerically integrated. The inclusion of electron inertia in the model allows us to obtain the value of the plasma floating potential as resulting from an electron density discontinuity at the walls, where the electrons attain sound velocity and the electric potential is continuous. Results from numerical computation are presented in terms of plots for densities, electric potential, and particles velocities. Comparison with results from literature, corresponding to electron Maxwell-Boltzmann distribution (neglecting electron inertia), is also shown.
Particle number fluctuations in the moment of inertia
International Nuclear Information System (INIS)
Allal, N.H.; Fellah, M.
1991-01-01
The nonphysical effects due to the false components introduced by the nonconservation of the particle number in the BCS states are eliminated in the theoretical values of the moment of inertia calculated by the microscopic cranking model. The states of the system are obtained by successive projections of the BCS states in the occupation number space. The moment of inertia appears then as a limit of a rapidly convergent sequence. The errors due to this false component have been numerically estimated and appear to be important both in the BCS states and in the matrix elements of the angular momentum. The predicted values of the moment of inertia satisfactorily reproduce the experimental data over a large number of nuclei within rare-earth and actinide regions with discrepancies ranging from 0.1% to 8%
Hysteretic transitions in the Kuramoto model with inertia.
Olmi, Simona; Navas, Adrian; Boccaletti, Stefano; Torcini, Alessandro
2014-10-01
We report finite-size numerical investigations and mean-field analysis of a Kuramoto model with inertia for fully coupled and diluted systems. In particular, we examine, for a gaussian distribution of the frequencies, the transition from incoherence to coherence for increasingly large system size and inertia. For sufficiently large inertia the transition is hysteretic, and within the hysteretic region clusters of locked oscillators of various sizes and different levels of synchronization coexist. A modification of the mean-field theory developed by Tanaka, Lichtenberg, and Oishi [Physica D 100, 279 (1997)] allows us to derive the synchronization curve associated to each of these clusters. We have also investigated numerically the limits of existence of the coherent and of the incoherent solutions. The minimal coupling required to observe the coherent state is largely independent of the system size, and it saturates to a constant value already for moderately large inertia values. The incoherent state is observable up to a critical coupling whose value saturates for large inertia and for finite system sizes, while in the thermodinamic limit this critical value diverges proportionally to the mass. By increasing the inertia the transition becomes more complex, and the synchronization occurs via the emergence of clusters of whirling oscillators. The presence of these groups of coherently drifting oscillators induces oscillations in the order parameter. We have shown that the transition remains hysteretic even for randomly diluted networks up to a level of connectivity corresponding to a few links per oscillator. Finally, an application to the Italian high-voltage power grid is reported, which reveals the emergence of quasiperiodic oscillations in the order parameter due to the simultaneous presence of many competing whirling clusters.
DEFF Research Database (Denmark)
Rezkalla, Michel M.N.; Martinenas, Sergejus; Zecchino, Antonio
2017-01-01
The high integration of renewable energy resources (inverter connected) replacing conventional generation reduces the available rotational inertia in the power system. This introduces the need for faster regulation services including synthetic inertia services. These services could potentially...... be provided by electric vehicles due to their fast response capability. This work evaluates and experimentally shows the capability and limits of EVs in providing synthetic inertia services. Three series produced EVs are used during the experiment. The results show the performance of the EVs in providing...... synthetic inertia. It shows also that, on the contrary of synchronous inertia, synthetic inertia might lead to unstable frequency behavior....
Moments of inertia and the shapes of Brownian paths
International Nuclear Information System (INIS)
Fougere, F.; Desbois, J.
1993-01-01
The joint probability law of the principal moments of inertia of Brownian paths (open or closed) is computed, using constrained path integrals and Random Matrix Theory. The case of two-dimensional paths is discussed in detail. In particular, it is shown that the ratio of the average values of the largest and smallest moments is equal to 4.99 (open paths) and 3.07 (closed paths). Results of numerical simulations are also presented, which include investigation of the relationships between the moments of inertia and the arithmetic area enclosed by a path. (authors) 28 refs., 2 figs
Frequency Stability Improvement of Low Inertia Systems Using Synchronous Condensers
DEFF Research Database (Denmark)
Nguyen, Ha Thi; Yang, Guangya; Nielsen, Arne Hejde
2016-01-01
of converter interfaced components (wind turbine, HVDC, and Photovoltaic) may have negative effects on the stability of the power system. These components do not have enough inertia response to control frequency excursion, so the power grid can depend on few synchronous machines for frequency regulation...... and reduce the system inertia. Consequently, the frequency stability of the system will be easily jeopardized. To address these issues, the paper studies frequency characteristics of future Western Danish renewable-based system that uses a majority of wind turbine generators. Different scenarios of wind...
Crustal fraction of moment of inertia in pulsars
International Nuclear Information System (INIS)
Atta, Debasis; Mukhopadhyay, Somnath; Basu, D.N.
2015-01-01
In the present work, stability of the β-equilibrated dense nuclear matter is analyzed with respect to the thermodynamic stability conditions. Based on the density dependent M3Y (DDM3Y) effective nucleon-nucleon (NN) interaction, the location of the inner edge of neutron star crusts and core-crust transition density and pressure are calculated and crustal fraction of moment of inertia is determined. These results for pressure and density at core-crust transition together with the observed minimum crustal fraction of the total moment of inertia provide a new limit for the radius of the Vela pulsar
Isolated colonic inertia is not usually the cause of chronic constipation.
Ragg, J; McDonald, R; Hompes, R; Jones, O M; Cunningham, C; Lindsey, I
2011-11-01
Chronic constipation is classified as outlet obstruction, colonic inertia or both. We aimed to determine the incidence of isolated colonic inertia in chronic constipation and to study symptom pattern in those with prolonged colonic transit time. Chronic constipation patients were classified radiologically by surgeon-reported defaecating proctography and transit study into four groups: isolated outlet obstruction, isolated colonic inertia, outlet obstruction plus colonic inertia, or normal. Symptom patterns were defined as stool infrequency (twice weekly or less) or frequent unsuccessful evacuations (more than twice weekly). Of 541 patients with chronic constipation, 289 (53%) were classified as isolated outlet obstruction, 26 (5%) as isolated colonic inertia, 159 (29%) as outlet obstruction plus colonic inertia and 67 (12%) as normal. Of 448 patients (83%) with outlet obstruction, 35% had additional colonic inertia. Only 14% of those with prolonged colonic transit time had isolated colonic inertia. Frequent unsuccessful evacuations rather than stool infrequency was the commonest symptom pattern in all three disease groups (isolated outlet obstruction 86%, isolated colonic inertia 54% and outlet obstruction plus colonic inertia 63%). Isolated colonic inertia is an unusual cause of chronic constipation. Most patients with colonic inertia have associated outlet obstruction. These data question the clinical significance of isolated colonic inertia. © 2011 The Authors. Colorectal Disease © 2011 The Association of Coloproctology of Great Britain and Ireland.
Directory of Open Access Journals (Sweden)
Christina N. Papadimitriou
2010-06-01
Full Text Available Storage devices are introduced in microgrids in order to secure their power quality, power regularity and offer ancillary services in a transient period. In the transition period of a low voltage microgrid, from the connected mode of operation to the islanded mode of operation, the power unbalance can be partly covered by the inertia energy of the existing power sources. This paper proposes fuzzy local controllers exploiting the inertia of a Wind Turbine (WT with a Doubly Fed Induction Generator (DFIG, if such a machine exists in the microgrid, in order to decrease the necessary storage devices and the drawbacks that arise. The proposed controllers are based in fuzzy logic due to the non linear and stochastic behavior of the system. Two cases are studied and compared during the transient period where the microgrid architecture and the DFIG controller differ. In the first case, the understudy microgrid includes a hybrid fuel cell system (FCS-battery system and a WT with a DFIGURE. The DFIG local controller in this case is also based in fuzzy logic and follows the classical optimum power absorption scenario for the WT. The transition of the microgrid from the connected mode of operation to the islanded mode is evaluated and, especially, the battery contribution is estimated. In the second case, the battery is eliminated. The fuzzy controller of the DFIG during the transition provides primary frequency control and local bus voltage support exploiting the WT inertia. The response of the system is estimated in both cases using MATLAB/Simulink software package.
Sinha, Nitish; Singh, Arun K.; Singh, Trilok N.
2018-04-01
A fundamental understanding of frictional sliding at rock surfaces is of practical importance for nucleation and propagation of earthquakes and rock slope stability. We investigate numerically the effect of different physical parameters such as inertia, viscous damping, temperature and normal stress on the chaotic behaviour of the two state variables rate and state friction (2sRSF) model. In general, a slight variation in any of inertia, viscous damping, temperature and effective normal stress reduces the chaotic behaviour of the sliding system. However, the present study has shown the appearance of chaos for the specific values of normal stress before it disappears again as the normal stress varies further. It is also observed that magnitude of system stiffness at which chaotic motion occurs, is less than the corresponding value of critical stiffness determined by using the linear stability analysis. These results explain the practical observation why chaotic nucleation of an earthquake is a rare phenomenon as reported in literature.
Inertial and viscous effects in the non linear growth of the tearing mode
International Nuclear Information System (INIS)
Edery, D.; Frey, M.; Tagger, M.; Soule, J.L.; Pellat, R.; Bussac, M.N.; Somon, J.P.
1982-08-01
The non linear self similar Tearing mode solution of Rutherford is revisited. We compute explicitly the stream function for the plasma flow including inertia, convection and viscosity. In all cases, Rutherford's solution is asymptotically valid
Bifurcations and Chaos of AN Immersed Cantilever Beam in a Fluid and Carrying AN Intermediate Mass
AL-QAISIA, A. A.; HAMDAN, M. N.
2002-06-01
The concern of this work is the local stability and period-doubling bifurcations of the response to a transverse harmonic excitation of a slender cantilever beam partially immersed in a fluid and carrying an intermediate lumped mass. The unimodal form of the non-linear dynamic model describing the beam-mass in-plane large-amplitude flexural vibration, which accounts for axial inertia, non-linear curvature and inextensibility condition, developed in Al-Qaisia et al. (2000Shock and Vibration7 , 179-194), is analyzed and studied for the resonance responses of the first three modes of vibration, using two-term harmonic balance method. Then a consistent second order stability analysis of the associated linearized variational equation is carried out using approximate methods to predict the zones of symmetry breaking leading to period-doubling bifurcation and chaos on the resonance response curves. The results of the present work are verified for selected physical system parameters by numerical simulations using methods of the qualitative theory, and good agreement was obtained between the analytical and numerical results. Also, analytical prediction of the period-doubling bifurcation and chaos boundaries obtained using a period-doubling bifurcation criterion proposed in Al-Qaisia and Hamdan (2001 Journal of Sound and Vibration244, 453-479) are compared with those of computer simulations. In addition, results of the effect of fluid density, fluid depth, mass ratio, mass position and damping on the period-doubling bifurcation diagrams are studies and presented.
System Inertia in the Changing Paradigm for Biodiversity ...
African Journals Online (AJOL)
The aim of this paper is to show that while there has been a change, at a policy level, from the old “conservation without a human face” to the new development for sustainable development, inertia in the policy implementation agencies has meant that the provisions of these new policy frameworks have not been translated ...
Organic food consumption in China: the moderating role of inertia
Directory of Open Access Journals (Sweden)
Yen Tsai-Fa
2018-01-01
Full Text Available Despite the progressive development of the organic food sector across Taiwan Strait, little is known about how consumers’ self congruity will influence organic food decision through various degrees of attitude and whether or not consumers with various degrees of inertia will vary in their intention to buy organic foods. The current study aims to examine the effect of consumption self congruity on behavioral intention related to organic food consumption under the mediating role of attitude as well as the moderating role of inertia. Research data were collected from organic food consumers across Taiwan Strait via a questionnaire survey, eventually obtaining 500 valid questionnaires for analysis. This study tested the overall model fit and hypotheses through structural equation modeling method (SEM. The results show that consumer attitude significantly mediates the effects of self congruity on organic food purchase intention. Moreover, the moderating effect of inertia is statistical significance, indicating that the relationship between attitude and purchase intention becomes weaker in the condition of consumers with higher degree of inertia. Several implications and suggestions are also discussed for organic food providers and marketers.
Role of inertia in the fracture of rock
International Nuclear Information System (INIS)
Passman, S.L.; Grady, D.E.; Rundle, J.B.
1980-01-01
A theory for the accumulation of damage in one dimension in fast deformation of a brittle material is developed. The theory is consistent with thermodynamics and takes crack inertia into account. The problem of damage accumulation due to a step pulse in strain is solved, and shows good agreement with experimental results
The inertia system coordinate transformation based on the Lobachevsky function
International Nuclear Information System (INIS)
Fadeev, N.G.
2001-01-01
Based on the interpretation of the Lobachevsky function cosΠ(ρ/k) = thρ/k as the function which expresses the constant light velocity principle at k = c (k is the Lobachevsky constant, c is the light velocity), the inertia system coordinate transformation of two kinds (one of them known as Lorentz transformation) have been obtained
Chimera states in coupled Kuramoto oscillators with inertia
International Nuclear Information System (INIS)
Olmi, Simona
2015-01-01
The dynamics of two symmetrically coupled populations of rotators is studied for different values of the inertia. The system is characterized by different types of solutions, which all coexist with the fully synchronized state. At small inertia, the system is no more chaotic and one observes mainly quasi-periodic chimeras, while the usual (stationary) chimera state is not anymore observable. At large inertia, one observes two different kind of chaotic solutions with broken symmetry: the intermittent chaotic chimera, characterized by a synchronized population and a population displaying a turbulent behaviour, and a second state where the two populations are both chaotic but whose dynamics adhere to two different macroscopic attractors. The intermittent chaotic chimeras are characterized by a finite life-time, whose duration increases as a power-law with the system size and the inertia value. Moreover, the chaotic population exhibits clear intermittent behavior, displaying a laminar phase where the two populations tend to synchronize, and a turbulent phase where the macroscopic motion of one population is definitely erratic. In the thermodynamic limit, these states survive for infinite time and the laminar regimes tends to disappear, thus giving rise to stationary chaotic solutions with broken symmetry contrary to what observed for chaotic chimeras on a ring geometry
Chimera states in coupled Kuramoto oscillators with inertia
Energy Technology Data Exchange (ETDEWEB)
Olmi, Simona, E-mail: simona.olmi@fi.isc.cnr.it [CNR - Consiglio Nazionale delle Ricerche - Istituto dei Sistemi Complessi, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); INFN Sez. Firenze, via Sansone, 1 - I-50019 Sesto Fiorentino (Italy)
2015-12-15
The dynamics of two symmetrically coupled populations of rotators is studied for different values of the inertia. The system is characterized by different types of solutions, which all coexist with the fully synchronized state. At small inertia, the system is no more chaotic and one observes mainly quasi-periodic chimeras, while the usual (stationary) chimera state is not anymore observable. At large inertia, one observes two different kind of chaotic solutions with broken symmetry: the intermittent chaotic chimera, characterized by a synchronized population and a population displaying a turbulent behaviour, and a second state where the two populations are both chaotic but whose dynamics adhere to two different macroscopic attractors. The intermittent chaotic chimeras are characterized by a finite life-time, whose duration increases as a power-law with the system size and the inertia value. Moreover, the chaotic population exhibits clear intermittent behavior, displaying a laminar phase where the two populations tend to synchronize, and a turbulent phase where the macroscopic motion of one population is definitely erratic. In the thermodynamic limit, these states survive for infinite time and the laminar regimes tends to disappear, thus giving rise to stationary chaotic solutions with broken symmetry contrary to what observed for chaotic chimeras on a ring geometry.
Time to wake up: reactive countermeasures to sleep inertia.
Hilditch, Cassie J; Dorrian, Jillian; Banks, Siobhan
2016-12-07
Sleep inertia is the period of impaired performance and grogginess experienced after waking. This period of impairment is of concern to workers who are on-call, or nap during work hours, and need to perform safety-critical tasks soon after waking. While several studies have investigated the best sleep timing and length to minimise sleep inertia effects, few have focused on countermeasures -especially those that can be implemented after waking (i.e. reactive countermeasures). This structured review summarises current literature on reactive countermeasures to sleep inertia such as caffeine, light, and temperature and discusses evidence for the effectiveness and operational viability of each approach. Current literature does not provide a convincing evidence-base for a reactive countermeasure. Caffeine is perhaps the best option, although it is most effective when administered prior to sleep and is therefore not strictly reactive. Investigations into light and temperature have found promising results for improving subjective alertness; further research is needed to determine whether these countermeasures can also attenuate performance impairment. Future research in this area would benefit from study design features highlighted in this review. In the meantime, it is recommended that proactive sleep inertia countermeasures are used, and that safety-critical tasks are avoided immediately after waking.
Chimera states in coupled Kuramoto oscillators with inertia.
Olmi, Simona
2015-12-01
The dynamics of two symmetrically coupled populations of rotators is studied for different values of the inertia. The system is characterized by different types of solutions, which all coexist with the fully synchronized state. At small inertia, the system is no more chaotic and one observes mainly quasi-periodic chimeras, while the usual (stationary) chimera state is not anymore observable. At large inertia, one observes two different kind of chaotic solutions with broken symmetry: the intermittent chaotic chimera, characterized by a synchronized population and a population displaying a turbulent behaviour, and a second state where the two populations are both chaotic but whose dynamics adhere to two different macroscopic attractors. The intermittent chaotic chimeras are characterized by a finite life-time, whose duration increases as a power-law with the system size and the inertia value. Moreover, the chaotic population exhibits clear intermittent behavior, displaying a laminar phase where the two populations tend to synchronize, and a turbulent phase where the macroscopic motion of one population is definitely erratic. In the thermodynamic limit, these states survive for infinite time and the laminar regimes tends to disappear, thus giving rise to stationary chaotic solutions with broken symmetry contrary to what observed for chaotic chimeras on a ring geometry.
Moment of Inertia of a Ping-Pong Ball
Cao, Xian-Sheng
2012-01-01
This note describes how to theoretically calculate and experimentally measure the moment of inertia of a Ping-Pong[R] ball. The theoretical calculation results are in good agreement with the experimental measurements that can be reproduced in an introductory physics laboratory.
Inaction inertia, regret, and valuation : A closer look
Zeelenberg, Marcel; Nijstad, Bernard A.; van Putten, Marijke; van Dijk, Eric
Inaction inertia is the phenomenon that one is not likely to act on an attractive opportunity after having bypassed an even more attractive opportunity. So far, all published work has assumed a causal role for the emotion regret in this effect. In a series of 5 experiments we found no support for
Determinacy, stock market dynamics and monetary policy inertia
DEFF Research Database (Denmark)
Pfajfar, Damjan; Santoro, Emiliano
2011-01-01
We study equilibrium determinacy in a New-Keynesian model where the Central Bank responds to asset prices growth. Unlike Taylor-type rules that react to asset prices, the proposed alternative does not harm dynamic stability and in certain cases promotes determinacy by inducing interest-rate inertia....
The Zone of Inertia: Absorptive Capacity and Organizational Change
Godkin, Lynn
2010-01-01
Purpose: The purpose of this paper is to describe how interruptions in organizational learning effect institutional absorptive capacity and contribute to organizational inertia. Design/methodology/approach: An exploratory model is presented as a heuristic to describe how interruptions in organizational learning affect absorptive capacity.…
Obstacles to Reasoning about Inertia in Different Contexts
Yerdelen-Damar, Sevda
2015-01-01
The present study investigated the underlying reasons for difficulties faced by students when they applied the concept of inertia across varying contexts. The participants of the study included five high school students. Data obtained from interviews were interpreted from the perspectives of the coordination class and epistemological framing…
Effects of electron inertia in capacitively coupled radio frequency discharges
International Nuclear Information System (INIS)
Xiang Nong
2004-01-01
The effects of the electron inertia on the plasma and sheath dynamics in capacitively coupled rf discharges with frequency ωω pi are investigated (here, ω and ω pi are the rf frequency and bulk ion plasma frequency, respectively). It is found that the effects of the electron inertia on the plasma density and ion velocity in the quasi-neutral region depend on the ratio of the amplitudes of the discharge current I rf and ion current I B =en 0 C s (here, e is the unit charge, n 0 is the plasma density at center, and C s is the ion sound speed). If the ratio is small so that I rf /I B √(m i /m e ) (here, m i and m e are ion and electron masses, respectively), the ion and time-averaged electron densities, ion velocity, and electric fields are little affected by the electron inertia. Otherwise, the effects of the electron inertia are significant. It is also shown that the assumption that the electrons obey the Boltzmann distribution in the sheath is invalid when the electron flux flowing to the electrode is significant
A method for measuring the inertia properties of rigid bodies
Gobbi, M.; Mastinu, G.; Previati, G.
2011-01-01
A method for the measurement of the inertia properties of rigid bodies is presented. Given a rigid body and its mass, the method allows to measure (identify) the centre of gravity location and the inertia tensor during a single test. The proposed technique is based on the analysis of the free motion of a multi-cable pendulum to which the body under consideration is connected. The motion of the pendulum and the forces acting on the system are recorded and the inertia properties are identified by means of a proper mathematical procedure based on a least square estimation. After the body is positioned on the test rig, the full identification procedure takes less than 10 min. The natural frequencies of the pendulum and the accelerations involved are quite low, making this method suitable for many practical applications. In this paper, the proposed method is described and two test rigs are presented: the first is developed for bodies up to 3500 kg and the second for bodies up to 400 kg. A validation of the measurement method is performed with satisfactory results. The test rig holds a third part quality certificate according to an ISO 9001 standard and could be scaled up to measure the inertia properties of huge bodies, such as trucks, airplanes or even ships.
Directory of Open Access Journals (Sweden)
L. O’connor Montero
2001-07-01
Full Text Available Se describen cálculos clásicos para determinar ejes y momentos principales de inercia de un cuerpo, y se demuestra que sepueden realizar cálculos con el mismo propósito mediante la aplicación del Cálculo Tensorial, la Teoría Espectral y elAlgebra Lineal. Esto permite justificar los términos del título del trabajo constituye una extensión del modelo tensorial a laestática, que en correspondencia con los elementos que lo definen y según analogías con otras aplicaciones a la mecánicadan lugar a introducir la noción de tensor de inercia de un cuerpo. Bien interpretado, el modelo puede contribuir a cambiosimportantes en la enseñanza del álgebra en la Ingeniería.Palabras claves: Tensor, cálculo tensorial, ejes y momentos principales de inercia, tensor de inercia.________________________________________________________________________________Abstract.The tensors calculation and the spectral theory are applied to modelling the inertia state (main axes and momentum ofinertia of a body. This makes possible to enrich static engineering calculations and to generalise tensorial models beyondthe materials resistance, fluids mechanic and the plastic deformation theory. Well interpretated, the model can lead toimportant changes in algebra teaching for mechanical engineers.Key words: Tension member, tension calculation, inertia main axes , principals inertia momentum, inertiatension member.
Effectiveness and clinical inertia in patients with antidiabetic therapy.
Machado-Duque, Manuel Enrique; Ramírez-Riveros, Adriana Carolina; Machado-Alba, Jorge Enrique
2017-06-01
To establish the effectiveness of antidiabetic therapy and the frequency of clinical inertia in the management of type 2 diabetes mellitus in Colombia. A cross-sectional study with follow-up of patients who had been treated for at least 1 year and were receiving medical consultation for antidiabetic treatment. Effectiveness was established when haemoglobin-A1c levels were inertia was reached, which was defined as no therapeutic modifications despite not achieving management controls. Sociodemographic, clinical and pharmacological variables were evaluated, and multivariate analyses were performed. In total, 363 patients with type 2 diabetes mellitus were evaluated, with a mean age of 62.0±12.2 years. A total of 1,016 consultations were evaluated, and the therapy was effective at the end of the follow-up in 57.9% of cases. Clinical inertia was found in 56.8% of patients who did not have metabolic control. The most frequently prescribed medications were metformin (84.0%), glibenclamide (23.4%) and insulin glargine (20.7%). Moreover, 57.6% of the patients were treated with two or more antidiabetic medications. Having metabolic control in the first consult of the follow-up was a protective factor against clinical inertia in the subsequent consultations (OR: 0.08; 95%CI: 0.04-0.15; Pinertia was identifiable and quantifiable and found in similar proportions to other countries. Clinical inertia is a relevant condition given that it interferes with the possibility of controlling this pathology. © 2017 John Wiley & Sons Ltd.
Validity, Reliability, and Inertia of Four Different Temperature Capsule Systems.
Bongers, Coen C W G; Daanen, Hein A M; Bogerd, Cornelis P; Hopman, Maria T E; Eijsvogels, Thijs M H
2018-01-01
Telemetric temperature capsule systems are wireless, relatively noninvasive, and easily applicable in field conditions and have therefore great advantages for monitoring core body temperature. However, the accuracy and responsiveness of available capsule systems have not been compared previously. Therefore, the aim of this study was to examine the validity, reliability, and inertia characteristics of four ingestible temperature capsule systems (i.e., CorTemp, e-Celsius, myTemp, and VitalSense). Ten temperature capsules were examined for each system in a temperature-controlled water bath during three trials. The water bath temperature gradually increased from 33°C to 44°C in trials 1 and 2 to assess the validity and reliability, and from 36°C to 42°C in trial 3 to assess the inertia characteristics of the temperature capsules. A systematic difference between capsule and water bath temperature was found for CorTemp (0.077°C ± 0.040°C), e-Celsius (-0.081°C ± 0.055°C), myTemp (-0.003°C ± 0.006°C), and VitalSense (-0.017°C ± 0.023°C; P 0.05). Comparable inertia characteristics were found for CorTemp (25 ± 4 s), e-Celsius (21 ± 13 s), and myTemp (19 ± 2 s), whereas the VitalSense system responded more slowly (39 ± 6 s) to changes in water bath temperature (P inertia were observed between capsule systems, an excellent validity, test-retest reliability, and inertia was found for each system between 36°C and 44°C after removal of outliers.
Smoothelin expression in the gastrointestinal tract: implication in colonic inertia.
Chan, Owen T M; Chiles, Lauren; Levy, Mary; Zhai, Jing; Yerian, Lisa M; Xu, Haodong; Xiao, Shu-Yuan; Soffer, Edy E; Conklin, Jeffrey L; Dhall, Deepti; Kahn, Melissa E; Balzer, Bonnie L; Amin, Mahul B; Wang, Hanlin L
2013-10-01
Colonic inertia is a frustrating motility disorder to patients, clinicians, and pathologists. The pathogenesis is largely unknown. The aims of this study were to: (1) characterize the expression of smoothelin, a novel smooth muscle-specific contractile protein expressed only by terminally differentiated smooth muscle cells, in the normal gastrointestinal (GI) tract; and (2) determine whether smoothelin is aberrantly expressed in patients with colonic inertia. A total of 57 resections of the normal GI tract (distal esophagus to left colon) were obtained from patients without GI motor dysfunction. Sixty-one colon resections were obtained from patients with a clinical diagnosis of colonic inertia. Smoothelin immunostaining was conducted on full-thickness tissue sections. In the nondysmotile controls, strong and diffuse cytoplasmic staining for smoothelin was observed in both the inner circular and outer longitudinal layers of the muscularis propria (MP) throughout the entire GI tract. The muscularis mucosae (MM) and muscular vessel walls were either completely negative or only patchily and weakly stained. The 1 exception to this pattern was observed in the distal esophagus, in which the MM was also diffusely and strongly stained. In cases with colonic inertia, a moderate to marked reduction of smoothelin immunoreactivity was observed in 15 of 61 (24.6%) colon resections, selectively seen in the outer layer of the MP. The data demonstrate that smoothelin is differentially expressed in the MP and MM of the normal GI tract and suggest that defective smoothelin expression may play a role in the pathogenesis of colonic inertia in a subset of patients.
Description of the turnover of the dynamical moment of inertia of the superdeformed nuclear state
International Nuclear Information System (INIS)
Yuxin Liu; Jiangang Song; Hong-zhou Sun; Jia-jun Wang; En-guang Zhao
1998-01-01
We propose in this paper an approach to describe the dynamical moment of inertia of superdeformed nuclear states in the spirit of variable moments of inertia. Both the general changing feature and the turnover of dynamical moments of inertia with rotational frequency are well described in our approach. It indicates that the competition between the angular momentum driving effect and the restraining effect plays a crucial role in determining the dynamical moments of inertia of superdeformed nuclear states. (author)
The role of population inertia in predicting the outcome of stage-structured biological invasions.
Guiver, Chris; Dreiwi, Hanan; Filannino, Donna-Maria; Hodgson, Dave; Lloyd, Stephanie; Townley, Stuart
2015-07-01
Deterministic dynamic models for coupled resident and invader populations are considered with the purpose of finding quantities that are effective at predicting when the invasive population will become established asymptotically. A key feature of the models considered is the stage-structure, meaning that the populations are described by vectors of discrete developmental stage- or age-classes. The vector structure permits exotic transient behaviour-phenomena not encountered in scalar models. Analysis using a linear Lyapunov function demonstrates that for the class of population models considered, a large so-called population inertia is indicative of successful invasion. Population inertia is an indicator of transient growth or decline. Furthermore, for the class of models considered, we find that the so-called invasion exponent, an existing index used in models for invasion, is not always a reliable comparative indicator of successful invasion. We highlight these findings through numerical examples and a biological interpretation of why this might be the case is discussed. Copyright © 2015. Published by Elsevier Inc.
Fast estimation of space-robots inertia parameters: A modular mathematical formulation
Nabavi Chashmi, Seyed Yaser; Malaek, Seyed Mohammad-Bagher
2016-10-01
This work aims to propose a new technique that considerably helps enhance time and precision needed to identify ;Inertia Parameters (IPs); of a typical Autonomous Space-Robot (ASR). Operations might include, capturing an unknown Target Space-Object (TSO), ;active space-debris removal; or ;automated in-orbit assemblies;. In these operations generating precise successive commands are essential to the success of the mission. We show how a generalized, repeatable estimation-process could play an effective role to manage the operation. With the help of the well-known Force-Based approach, a new ;modular formulation; has been developed to simultaneously identify IPs of an ASR while it captures a TSO. The idea is to reorganize the equations with associated IPs with a ;Modular Set; of matrices instead of a single matrix representing the overall system dynamics. The devised Modular Matrix Set will then facilitate the estimation process. It provides a conjugate linear model in mass and inertia terms. The new formulation is, therefore, well-suited for ;simultaneous estimation processes; using recursive algorithms like RLS. Further enhancements would be needed for cases the effect of center of mass location becomes important. Extensive case studies reveal that estimation time is drastically reduced which in-turn paves the way to acquire better results.
40 CFR 86.129-00 - Road load power, test weight, and inertia weight class determination.
2010-07-01
... inertia weight class determination. 86.129-00 Section 86.129-00 Protection of Environment ENVIRONMENTAL... power, test weight, and inertia weight class determination. Applicability. Section 86.129-94 (a) applies... testing using paragraphs (e)(1) and (e)(2) of this section. (f)(1) Required test dynamometer inertia...
40 CFR 86.229-94 - Road load force, test weight, and inertia weight class determination.
2010-07-01
... inertia weight class determination. 86.229-94 Section 86.229-94 Protection of Environment ENVIRONMENTAL... § 86.229-94 Road load force, test weight, and inertia weight class determination. (a) Flywheels... vehicle weight (pounds) Equivalent test weight (pounds) Inertia weight class (pounds) Up-1,062 1,000 1,000...
40 CFR 86.129-80 - Road load power, test weight, and inertia weight class determination.
2010-07-01
... inertia weight class determination. 86.129-80 Section 86.129-80 Protection of Environment ENVIRONMENTAL... power, test weight, and inertia weight class determination. (a) Flywheels, electrical or other means of... weight (pounds) Equivalent test weight (pounds) Inertia weight class (pounds) Up to 1,062 1,000 1,000 1...
40 CFR 86.529-98 - Road load force and inertia weight determination.
2010-07-01
... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Road load force and inertia weight... inertia weight determination. (a)(1) Road load as a function of speed is given by the following equation: F = A + CV2 (2) The values for coefficients A and C and the test inertia are given in Figure F98-9...
On the influence of microscale inertia on dynamic ductile crack extension
Jacques, N.; Mercier, S.; Molinari, A.
2012-08-01
The present paper is devoted to the modelling of damage by micro-voiding in ductile solids under dynamic loading conditions. Using a dynamic homogenization procedure, a constitutive damage model accounting for inertial effects due to void growth (microscale inertia or micro-inertia) has been developed. The role played by microscale inertia in dynamic ductile crack growth is investigated with the use of the proposed micromechanical modelling. It is found that micro-inertia has a significant influence on the fracture behaviour. Micro-inertia limits the velocity at which cracks propagate. It also contributes to increase the apparent dynamic toughness of the material.
The impact of pedestal turbulence and electron inertia on edge-localized-mode crashes
Energy Technology Data Exchange (ETDEWEB)
Xi, P. W. [FSC and State Key Lab of Nuclear Physics and Technology, Department of Physics, Peking University, Beijing 100871 (China); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Xu, X. Q. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Diamond, P. H. [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon (Korea, Republic of); Center for Astrophysics and Space Sciences and Department of Physics, University of California San Diego, La Jolla, California 92093-0429 (United States)
2014-05-15
We demonstrate that the occurrence of Edge-Localized-Modes (ELM) crashes does not depend only on the linear peeling-ballooning threshold, but also relies on nonlinear processes. Wave-wave interaction constrains the growth time of a mode, thus inducing a shift in the criterion for triggering an ELM crash. An ELM crash requires the P-B growth rate to exceed a critical value γ>γ{sub c}, where γ{sub c} is set by 1/τ{sup ¯}{sub c}, and τ{sup ¯}{sub c} is the averaged mode phase coherence time. For 0<γ<γ{sub c}, P-B turbulence develops but drives enhanced turbulent transport. We also show that electron inertia dramatically changes the instability threshold when density is low. However, P-B turbulence alone cannot generate enough current transport to allow fast reconnection during an ELM crash.
Dynamic moments of inertia in Xe, Cs and Ba nuclei
International Nuclear Information System (INIS)
El-Samman, H.; Barci, V.; Gizon, A.
1984-01-01
The γ-rays following the reactions induced by 12 C ions on 115 In, 112 , 117 , 122 Sn and 123 Sb targets have been investigated using six NaI(Tl) detectors in a two-dimensional arrangement. The collective moment of inertia I( 2 ) /sub band/ of 118 , 122 Xe, 123 Cs and 128 , 130 Ba have been extracted from the energy-correlation spectra. The behaviour of these nuclei and the observed differences are interpreted in terms of high-spin collective properties. Data are also presented on the effective moment of inertia I( 2 )/sub eff/ of 118 Xe and 130 Ba measured by sum-spectrometer techniques. 13 references
Calculations of mass and moment of inertia for neutron stars
International Nuclear Information System (INIS)
Moelnvik, T.; Oestgaard, E.
1985-01-01
Masses and moments of inertia for slowly-rotating neutron stars are calculated from the Tolman-Oppenheimer-Volkoff equations and various equations of state for neutron-star matter. We have also obtained pressure and density as a function of the distance from the centre of the star. Generally, two different equations of state are applied for particle densities n>0.47 fm -3 and n -3 . The maximum mass is, in our calculations for all equations of state except for the unrealistic non-relativistic ideal Fermi gas, given by 1.50 Msub(sun) 44 gxcm 2 45 gxcm 2 , which also seem to agree very well with 'experimental results'. The radius of the star corresponding to maximum mass and maximum moment of inertia is given by 8.2 km< R<10.0 km, but a smaller central density rhosub(c) will give a larger radius. (orig.)
More about the moment of inertia of Mars
International Nuclear Information System (INIS)
Kaula, W.M.; Sleep, N.H.; Phillips, R.J.
1989-01-01
The maximum allowable mean moment-of-inertia I of Mars is 0.3650 ·MR 2 because the rate-of-adjustment of the rotation axis is much faster than the rate-of-generation of density heterogeneities, as with any planet. But Mars differs from the other terrestrial planets in that its gravity field is rougher, in the sense of stress-difference implication, and its global tectonics is dominated by one feature, centered on the Tharsis Plateau. Plausible tectonic models of Mars require generation and support that are almost axially symmetric about Tharsis. Hence, unlike other terrestrial planets, Mars likely has two non-hydrostatic components of moments-of-inertia that are nearly equal, and the most probable value of I/MR 2 is slightly less than 0.3650
Motion, inertia and special relativity-a novel perspective
International Nuclear Information System (INIS)
Masreliez, C Johan
2007-01-01
A recent paper by the author proposes that the phenomenon of inertia may be explained if the four metrical coefficients in the Minkowskian line element were to change as a consequence of acceleration. A certain scale factor multiplying the four metrical coefficients was found, which depends solely on velocity. This dynamic scale factor, which is [1-(v/c) 2 )], models inertia as a gravitational-type phenomenon. With this metric the geodesic of general relativity is an identity, and all accelerating trajectories are geodesics. This paper shows that the same scale factor also agrees with special relativity, but offers a new perspective. A new kind of dynamic process involving four-dimensional scale transition is proposed
Analysis of anisotropic shells containing flowing fluid
International Nuclear Information System (INIS)
Lakis, A.A.
1983-01-01
A general theory for the dynamic analysis of anisotropic thin cylindrical shells containing flowing fluid is presented. The shell may be uniform or non-uniform, provided it is geometrically axially symmetric. This is a finite- element theory, using cylindrical finite elements, but the displacement functions are determined by using classical shell theory. A new solution of the wave equation of the liquid finite element leads to an expression of the fluid pressure, p, as a function of the nodal displacements of the element and three operative forces (inertia, centrifugal and Coriolis) of the moving fluid. (Author) [pt
Testing for clinical inertia in medication treatment of bipolar disorder.
Hodgkin, Dominic; Merrick, Elizabeth L; O'Brien, Peggy L; McGuire, Thomas G; Lee, Sue; Deckersbach, Thilo; Nierenberg, Andrew A
2016-11-15
Clinical inertia has been defined as lack of change in medication treatment at visits where a medication adjustment appears to be indicated. This paper seeks to identify the extent of clinical inertia in medication treatment of bipolar disorder. A second goal is to identify patient characteristics that predict this treatment pattern. Data describe 23,406 visits made by 1815 patients treated for bipolar disorder during the STEP-BD practical clinical trial. Visits were classified in terms of whether a medication adjustment appears to be indicated, and also whether or not one occurred. Multivariable regression analyses were conducted to find which patient characteristics were predictive of whether adjustment occurred. 36% of visits showed at least 1 indication for adjustment. The most common indications were non-response to medication, side effects, and start of a new illness episode. Among visits with an indication for adjustment, no adjustment occurred 19% of the time, which may be suggestive of clinical inertia. In multivariable models, presence of any indication for medication adjustment was a predictor of receiving one (OR=1.125, 95% CI =1.015, 1.246), although not as strong as clinical status measures. The associations observed are not necessarily causal, given the study design. The data also lack information about physician-patient communication. Many patients remained on the same medication regimen despite indications of side effects or non-response to treatment. Although lack of adjustment does not necessarily reflect clinical inertia in all cases, the reasons for this treatment pattern merit further examination. Copyright © 2016 Elsevier B.V. All rights reserved.
Analysis of neoclassical edge plasma transport with gyroviscosity and inertia
International Nuclear Information System (INIS)
Rogister, A.; Antonov, N.
1996-01-01
It is shown that the ambipolarity constraint which results from neoclassical transport theory with gyroviscosity and inertia sets lower limits on the edge density and/or temperature and/or Z eff gradients. Toroidal momentum co, respectively counter, -injection reduces, respectively increases these lower bounds. Generally speaking, co, respectively counter, -injection increases, respectively reduces, the rotation velocities. The theory has so far been developed for the high collisionality regime only. (orig.)
On the Inertia Term of Projectile's Penetration Resistance
Directory of Open Access Journals (Sweden)
Yu Shan
2013-01-01
Full Text Available The effect of the target inertia term of rigid kinetic energy projectiles (KEP’s penetration resistance is investigated using nonlinear dynamic code LS-DYNA and four constitutive models. It is found that the damage number of target can be used to measure the influence of the inertia term. The smaller the damage number is, the less influence the inertia term has. The less dependent the resistance has on projectile velocity, the more accurate it is to treat the resistance as a constant. For the ogive-nose projectile with CRH of 3, when the target is aluminum, steel, or other metals, the threshold velocity for the constant resistance is at least 1258 m/s; when the target is concrete, rock, or other brittle materials, if the velocity of the projectile is greater than 400 m/s or so, the damage number would be very large, and the penetration resistance would clearly depend on the projectile’s velocity. The higher the elastic wave velocity is, the more penetration process is affected by the impact face.
Explicit expression for effective moment of inertia of RC beams
Directory of Open Access Journals (Sweden)
K.A. Patel
Full Text Available AbstractDeflection is an important design parameter for structures subjected to service load. This paper provides an explicit expression for effective moment of inertia considering cracking, for uniformly distributed loaded reinforced concrete (RC beams. The proposed explicit expression can be used for rapid prediction of short-term deflection at service load. The explicit expression has been obtained from the trained neural network considering concrete cracking, tension stiffening and entire practical range of reinforcement. Three significant structural parameters have been identified that govern the change in effective moment of inertia and therefore deflection. These three parameters are chosen as inputs to train neural network. The training data sets for neural network are generated using finite element software ABAQUS. The explicit expression has been validated for a number of simply supported and continuous beams and it is shown that the predicted deflections have reasonable accuracy for practical purpose. A sensitivity analysis has been performed, which indicates substantial dependence of effective moment of inertia on the selected input parameters.
Nuclear inertia for fission in a generalized cranking model
International Nuclear Information System (INIS)
Kunz, J.; Nix, J.R.
1984-01-01
The Inglis cranking model has been widely used to calculate the nuclear inertia associated with collective degrees of freedom. After the inclusion of pairing correlations, theoretical results obtained with the cranking model for nuclear rotations and γ-vibrations were in relatively good agreement with experimental data. Calculations of β-vibrational inertias were also performed in the cranking model for fission deformations. Theoretical results were several times the irrotational values and gave reasonable agreement with experimental spontaneous-fission lifetimes, although in one study a renormalization factor of 0.8 was required. However, as pointed out by many authors, the Inglis cranking model possesses two serious deficiencies. First, problems arise when the single-particle potential contains momentum-dependence terms. Second, in the limit of large pairing strength the inertia approaches zero instead of a finite (irrotational) limit. Alternative approaches to the cranking model which did not lead to such unacceptable results were developed by Migdal, Belyaev and Thouless and Valatin. They showed that these deficiencies of the cranking model are due to a lack of self-consistency, since the reaction of the mean field to the collective motion is neglected in the Inglis model. Previously we used their arguments and developed a generalized cranking model for stationary collective motion. Here it is shown how to develop a time-dependent formalism appropriate to β-vibrations and fission. 10 references
Testing and Validation of the Dynamic Inertia Measurement Method
Chin, Alexander W.; Herrera, Claudia Y.; Spivey, Natalie D.; Fladung, William A.; Cloutier, David
2015-01-01
The Dynamic Inertia Measurement (DIM) method uses a ground vibration test setup to determine the mass properties of an object using information from frequency response functions. Most conventional mass properties testing involves using spin tables or pendulum-based swing tests, which for large aerospace vehicles becomes increasingly difficult and time-consuming, and therefore expensive, to perform. The DIM method has been validated on small test articles but has not been successfully proven on large aerospace vehicles. In response, the National Aeronautics and Space Administration Armstrong Flight Research Center (Edwards, California) conducted mass properties testing on an "iron bird" test article that is comparable in mass and scale to a fighter-type aircraft. The simple two-I-beam design of the "iron bird" was selected to ensure accurate analytical mass properties. Traditional swing testing was also performed to compare the level of effort, amount of resources, and quality of data with the DIM method. The DIM test showed favorable results for the center of gravity and moments of inertia; however, the products of inertia showed disagreement with analytical predictions.
Falling, flapping, flying, swimming,...: High-Re fluid-solid interactions with vortex shedding
Michelin, Sebastien Honore Roland
The coupling between the motion of a solid body and the dynamics of the surrounding flow is essential to the understanding of a large number of engineering and physical problems, from the stability of a slender structure exposed to the wind to the locomotion of insects, birds and fishes. Because of the strong coupling on a moving boundary of the equations for the solid and fluid, the simulation of such problems is computationally challenging and expensive. This justifies the development of simplified models for the fluid-solid interactions to study their physical properties and behavior. This dissertation proposes a reduced-order model for the interaction of a sharp-edged solid body with a strongly unsteady high Reynolds number flow. In such a case, viscous forces in the fluid are often negligible compared to the fluid inertia or the pressure forces, and the thin boundary layers separate from the solid at the edges, leading to the shedding of large and persistent vortices in the solid's wake. A general two-dimensional framework is presented based on complex potential flow theory. The formation of the solid's vortical wake is accounted for by the shedding of point vortices with unsteady intensity from the solid's sharp edges, and the fluid-solid problem is reformulated exclusively as a solid-vortex interaction problem. In the case of a rigid solid body, the coupled problem is shown to reduce to a set of non-linear ordinary differential equations. This model is used to study the effect of vortex shedding on the stability of falling objects. The solid-vortex model is then generalized to study the fluttering instability and non-linear flapping dynamics of flexible plates or flags. The uttering instability and resulting flapping motion result from the competing effects of the fluid forcing and of the solid's flexural rigidity and inertia. Finally, the solid-vortex model is applied to the study of the fundamental effect of bending rigidity on the flapping performance of
Inertial effects on the stress generation of active fluids
Takatori, S. C.; Brady, J. F.
2017-09-01
Suspensions of self-propelled bodies generate a unique mechanical stress owing to their motility that impacts their large-scale collective behavior. For microswimmers suspended in a fluid with negligible particle inertia, we have shown that the virial swim stress is a useful quantity to understand the rheology and nonequilibrium behaviors of active soft matter systems. For larger self-propelled organisms such as fish, it is unclear how particle inertia impacts their stress generation and collective movement. Here we analyze the effects of finite particle inertia on the mechanical pressure (or stress) generated by a suspension of self-propelled bodies. We find that swimmers of all scales generate a unique swim stress and Reynolds stress that impact their collective motion. We discover that particle inertia plays a similar role as confinement in overdamped active Brownian systems, where the reduced run length of the swimmers decreases the swim stress and affects the phase behavior. Although the swim and Reynolds stresses vary individually with the magnitude of particle inertia, the sum of the two contributions is independent of particle inertia. This points to an important concept when computing stresses in computer simulations of nonequilibrium systems: The Reynolds and the virial stresses must both be calculated to obtain the overall stress generated by a system.
The role of inertia in modeling decisions from experience with instance-based learning.
Dutt, Varun; Gonzalez, Cleotilde
2012-01-01
One form of inertia is the tendency to repeat the last decision irrespective of the obtained outcomes while making decisions from experience (DFE). A number of computational models based upon the Instance-Based Learning Theory, a theory of DFE, have included different inertia implementations and have shown to simultaneously account for both risk-taking and alternations between alternatives. The role that inertia plays in these models, however, is unclear as the same model without inertia is also able to account for observed risk-taking quite well. This paper demonstrates the predictive benefits of incorporating one particular implementation of inertia in an existing IBL model. We use two large datasets, estimation and competition, from the Technion Prediction Tournament involving a repeated binary-choice task to show that incorporating an inertia mechanism in an IBL model enables it to account for the observed average risk-taking and alternations. Including inertia, however, does not help the model to account for the trends in risk-taking and alternations over trials compared to the IBL model without the inertia mechanism. We generalize the two IBL models, with and without inertia, to the competition set by using the parameters determined in the estimation set. The generalization process demonstrates both the advantages and disadvantages of including inertia in an IBL model.
Accounting for inertia in modal choices: some new evidence using a RP/SP dataset
DEFF Research Database (Denmark)
Cherchi, Elisabetta; Manca, Francesco
2011-01-01
effect is stable along the SP experiments. Inertia has been studied more extensively with panel datasets, but few investigations have used RP/SP datasets. In this paper we extend previous work in several ways. We test and compare several ways of measuring inertia, including measures that have been...... proposed for both short and long RP panel datasets. We also explore new measures of inertia to test for the effect of “learning” (in the sense of acquiring experience or getting more familiar with) along the SP experiment and we disentangle this effect from the pure inertia effect. A mixed logit model...... is used that allows us to account for both systematic and random taste variations in the inertia effect and for correlations among RP and SP observations. Finally we explore the relation between the utility specification (especially in the SP dataset) and the role of inertia in explaining current choices....
Test of neural inertia in humans during general anaesthesia.
Kuizenga, M H; Colin, P J; Reyntjens, K M E M; Touw, D J; Nalbat, H; Knotnerus, F H; Vereecke, H E M; Struys, M M R F
2018-03-01
Neural inertia is defined as the tendency of the central nervous system to resist transitions between arousal states. This phenomenon has been observed in mice and Drosophila anaesthetized with volatile anaesthetics: the effect-site concentration required to induce anaesthesia in 50% of the population (C 50 ) was significantly higher than the effect-site concentration for 50% of the population to recover from anaesthesia. We evaluated this phenomenon in humans using propofol or sevoflurane (both with or without remifentanil) as anaesthetic agents. Thirty-six healthy volunteers received four sessions of anaesthesia with different drug combinations in a step-up/step-down design. Propofol or sevoflurane was administered with or without remifentanil. Serum concentrations of propofol and remifentanil were measured from arterial blood samples. Loss and return of responsiveness (LOR-ROR), response to pain (PAIN), Patient State Index (PSI) and spectral edge frequency (SEF) were modeled with NONMEM®. For propofol, the C 50 for induction and recovery of anaesthesia was not significantly different across the different endpoints. For sevoflurane, for all endpoints except SEF, significant differences were found. For some endpoints (LOR and PAIN) the difference was significant only when sevoflurane was combined with remifentanil. Our results nuance earlier findings with volatile anaesthetics in mice and Drosophila. Methodological aspects of the study, such as the measured endpoint, influence the detection of neural inertia. A more thorough definition of neural inertia, with a robust methodological framework for clinical studies is required to advance our knowledge of this phenomenon. NCT 02043938. Copyright © 2017 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Wen, Li; Lauder, George
2013-01-01
Recent advances in understanding fish locomotion with robotic devices have included the use of flapping foil robots that swim at a constant swimming speed. However, the speed of even steadily swimming live fishes is not constant because the fish center of mass oscillates axially throughout a tail beat cycle. In this paper, we couple a linear motor that produces controlled oscillations in the axial direction to a robotic flapping foil apparatus to model both axial and side to side oscillatory motions used by freely-swimming fishes. This experimental arrangement allows us to compensate for the substantial inertia of the carriage and motors that drive the oscillating foils. We identify a ‘critically-oscillated’ amplitude of axial motion at which the cyclic oscillations in axial locomotor force are greatly reduced throughout the flapping cycle. We studied the midline kinematics, power consumption and wake flow patterns of non-rigid foils with different lengths and flexural stiffnesses at a variety of axial oscillation amplitudes. We found that ‘critically-oscillated’ peak-to-peak axial amplitudes on the order of 1.0 mm and at the correct phase are sufficient to mimic center of mass motion, and that such amplitudes are similar to center of mass oscillations recorded for freely-swimming live fishes. Flow visualization revealed differences in wake flows of flexible foils between the ‘non-oscillated’ and ‘critically-oscillated’ states. Inertia-compensating methods provide a novel experimental approach for studying aquatic animal swimming, and allow instrumented robotic swimmers to display center of mass oscillations similar to those exhibited by freely-swimming fishes. (paper)
High-inertia drive motors and their starting characteristics
International Nuclear Information System (INIS)
Anon.
1980-01-01
The motor for a large reactor coolant pump failed while starting. The motor-application and the motor-failure are discussed in detail. A review of applications of motors for high-inertia drives shows that a motor designed and built to today's industry-standards might be overstressed while experiencing abnormal starting conditions, even though its protection is in accord with accepted practice. The inter-relationship between motor characteristics and characteristics of various types of protection are discussed, briefly. The review concludes that motor specifications and motor standards should be augmented. 1 ref
A dynamic marketing model with best reply and inertia
International Nuclear Information System (INIS)
Bischi, Gian Italo; Cerboni Baiardi, Lorenzo
2015-01-01
In this paper we consider a nonlinear discrete-time dynamic model proposed by Farris et al. (2005) as a market share attraction model with two firms that decide marketing efforts over time according to best reply strategies with naïve expectations. The model also considers an adaptive adjustment toward best reply, a form of inertia or anchoring attitude, and we investigate the effects of heterogeneities among firms. A rich scenario of local and global bifurcations is obtained even with just two competing firms, and a comparison is proposed with apparently similar duopoly models based on repeated best reply dynamics with naïve expectations and adaptive adjustment.
A dynamic inertia weight particle swarm optimization algorithm
International Nuclear Information System (INIS)
Jiao Bin; Lian Zhigang; Gu Xingsheng
2008-01-01
Particle swarm optimization (PSO) algorithm has been developing rapidly and has been applied widely since it was introduced, as it is easily understood and realized. This paper presents an improved particle swarm optimization algorithm (IPSO) to improve the performance of standard PSO, which uses the dynamic inertia weight that decreases according to iterative generation increasing. It is tested with a set of 6 benchmark functions with 30, 50 and 150 different dimensions and compared with standard PSO. Experimental results indicate that the IPSO improves the search performance on the benchmark functions significantly
An object oriented implementation of the Yeadon human inertia model.
Dembia, Christopher; Moore, Jason K; Hubbard, Mont
2014-01-01
We present an open source software implementation of a popular mathematical method developed by M.R. Yeadon for calculating the body and segment inertia parameters of a human body. The software is written in a high level open source language and provides three interfaces for manipulating the data and the model: a Python API, a command-line user interface, and a graphical user interface. Thus the software can fit into various data processing pipelines and requires only simple geometrical measures as input.
An object oriented implementation of the Yeadon human inertia model
Dembia, Christopher; Moore, Jason K.; Hubbard, Mont
2015-01-01
We present an open source software implementation of a popular mathematical method developed by M.R. Yeadon for calculating the body and segment inertia parameters of a human body. The software is written in a high level open source language and provides three interfaces for manipulating the data and the model: a Python API, a command-line user interface, and a graphical user interface. Thus the software can fit into various data processing pipelines and requires only simple geometrical measures as input. PMID:25717365
Bewley, Lee W
2010-01-01
Structural inertia is the overall capacity of an organization to adapt within a market environment. This paper reviews the impact of healthcare investments in information management/information technology (IM/IT) on the strategic management concept of structural inertia. Research indicates that healthcare executives should consider the relative state of structural inertia for their firms and match them with potential IM/IT solutions. Additionally, organizations should favorably consider IM/IT solutions that are comparatively less complex.
Changes in inertia and effect on turning effort across different wheelchair configurations.
Caspall, Jayme J; Seligsohn, Erin; Dao, Phuc V; Sprigle, Stephen
2013-01-01
When executing turning maneuvers, manual wheelchair users must overcome the rotational inertia of the wheelchair system. Differences in wheelchair rotational inertia can result in increases in torque required to maneuver, resulting in greater propulsion effort and stress on the shoulder joints. The inertias of various configurations of an ultralightweight wheelchair were measured using a rotational inertia-measuring device. Adjustments in axle position, changes in wheel and tire type, and the addition of several accessories had various effects on rotational inertias. The configuration with the highest rotational inertia (solid tires, mag wheels with rearward axle) exceeded the configuration with the lowest (pneumatic tires, spoke wheels with forward axle) by 28%. The greater inertia requires increased torque to accelerate the wheelchair during turning. At a representative maximum acceleration, the reactive torque spanned the range of 11.7 to 15.0 N-m across the wheelchair configurations. At higher accelerations, these torques exceeded that required to overcome caster scrub during turning. These results indicate that a wheelchair's rotational inertia can significantly influence the torque required during turning and that this influence will affect active users who turn at higher speeds. Categorizing wheelchairs using both mass and rotational inertia would better represent differences in effort during wheelchair maneuvers.
Shilov, Georgi E
1977-01-01
Covers determinants, linear spaces, systems of linear equations, linear functions of a vector argument, coordinate transformations, the canonical form of the matrix of a linear operator, bilinear and quadratic forms, Euclidean spaces, unitary spaces, quadratic forms in Euclidean and unitary spaces, finite-dimensional space. Problems with hints and answers.
Directory of Open Access Journals (Sweden)
Olivier eWhite
2015-02-01
Full Text Available In everyday life, one of the most frequent activities involves accelerating and decelerating an object held in precision grip. In many contexts, humans scale and synchronize their grip force, normal to the finger/object contact, in anticipation of the expected tangential load force, resulting from the combination of the gravitational and the inertial forces. In many contexts, grip force and load force are linearly coupled. A few studies have examined how we adjust the parameters - gain and offset - of this linear relationship. However, the question remains open as to how the brain adjusts grip force regardless of whether load force is generated by different combinations of weight and inertia. Here, we designed conditions to generate equivalent magnitudes of load force by independently varying mass and movement frequency. In a control experiment, we directly manipulated gravity in parabolic flights, while other factors remained constant. We show with a simple computational approach that, to adjust grip force, the brain is sensitive to how load forces are produced at the fingertips. This provides clear evidence that the analysis of the origin of load force is performed centrally, and not only at the periphery.
White, Olivier
2015-01-01
In everyday life, one of the most frequent activities involves accelerating and decelerating an object held in precision grip. In many contexts, humans scale and synchronize their grip force (GF), normal to the finger/object contact, in anticipation of the expected tangential load force (LF), resulting from the combination of the gravitational and the inertial forces. In many contexts, GF and LF are linearly coupled. A few studies have examined how we adjust the parameters–gain and offset–of this linear relationship. However, the question remains open as to how the brain adjusts GF regardless of whether LF is generated by different combinations of weight and inertia. Here, we designed conditions to generate equivalent magnitudes of LF by independently varying mass and movement frequency. In a control experiment, we directly manipulated gravity in parabolic flights, while other factors remained constant. We show with a simple computational approach that, to adjust GF, the brain is sensitive to how LFs are produced at the fingertips. This provides clear evidence that the analysis of the origin of LF is performed centrally, and not only at the periphery. PMID:25717293
Energy Technology Data Exchange (ETDEWEB)
Kerbel, G.D.
1981-01-20
A study is made of a scale model in three dimensions of a guiding center plasma within the purview of gyroelastic (also known as finite gyroradius-near theta pinch) magnetohydrodynamics. The (nonlinear) system sustains a particular symmetry called isorrhopy which permits the decoupling of fluid modes from drift modes. Isorrhopic equilibria are analyzed within the framework of geometrical optics resulting in (local) dispersion relations and ray constants. A general scheme is developed to evolve an arbitrary linear perturbation of a screwpinch equilibrium as an invertible integral transform (over the complete set of generalized eigenfunctions defined naturally by the equilibrium). Details of the structure of the function space and the associated spectra are elucidated. Features of the (global) dispersion relation owing to the presence of gyroelastic stabilization are revealed. An energy principle is developed to study the stability of the tubular screwpinch.
International Nuclear Information System (INIS)
Kerbel, G.D.
1981-01-01
A study is made of a scale model in three dimensions of a guiding center plasma within the purview of gyroelastic (also known as finite gyroradius-near theta pinch) magnetohydrodynamics. The (nonlinear) system sustains a particular symmetry called isorrhopy which permits the decoupling of fluid modes from drift modes. Isorrhopic equilibria are analyzed within the framework of geometrical optics resulting in (local) dispersion relations and ray constants. A general scheme is developed to evolve an arbitrary linear perturbation of a screwpinch equilibrium as an invertible integral transform (over the complete set of generalized eigenfunctions defined naturally by the equilibrium). Details of the structure of the function space and the associated spectra are elucidated. Features of the (global) dispersion relation owing to the presence of gyroelastic stabilization are revealed. An energy principle is developed to study the stability of the tubular screwpinch
Independent effects of adding weight and inertia on balance during quiet standing.
Costello, Kerry Elizabeth; Matrangola, Sara Louise; Madigan, Michael Lawrence
2012-04-16
Human balance during quiet standing is influenced by adding mass to the body with a backpack, with symmetrically-applied loads to the trunk, or with obesity. Adding mass to the body increases both the weight and inertia of the body, which theoretically could provide counteracting effects on body dynamics and balance. Understanding the independent effects of adding weight and inertia on balance may provide additional insight into human balance that could lead to novel advancements in balance training and rehabilitation. Therefore, the purpose of this study was to investigate the independent effects of adding weight and inertia on balance during quiet standing. Sixteen normal-weight young adult participants stood as still as possible on a custom-built backboard apparatus under four experimental conditions: baseline, added inertia only, added weight only, and added inertia and weight. Adding inertia by itself had no measurable effect on center of pressure movement or backboard movement. Adding weight by itself increased center of pressure movement (indicated greater effort by the postural control system to stand as still as possible) and backboard movement (indicating a poorer ability of the body to stand as still as possible). Adding inertia and weight at the same time increased center of pressure movement but did not increase backboard movement compared to the baseline condition. Adding inertia and adding weight had different effects on balance. Adding inertia by itself had no effect on balance. Adding weight by itself had a negative effect on balance. When adding inertia and weight at the same time, the added inertia appeared to lessen (but did not eliminate) the negative effect of adding weight on balance. These results improve our fundamental understanding of how added mass influences human balance.
A cyber-physical approach to experimental fluid mechanics
Mackowski, Andrew Williams
This Thesis documents the design, implementation, and use of a novel type of experimental apparatus, termed Cyber-Physical Fluid Dynamics (CPFD). Unlike traditional fluid mechanics experiments, CPFD is a general-purpose technique that allows one to impose arbitrary forces on an object submerged in a fluid. By combining fluid mechanics with robotics, we can perform experiments that would otherwise be incredibly difficult or time-consuming. More generally, CPFD allows a high degree of automation and control of the experimental process, allowing for much more efficient use of experimental facilities. Examples of CPFD's capabilites include imposing a gravitational force in the horizontal direction (allowing a test object to "fall" sideways in a water channel), simulating nonlinear springs for a vibrating fluid-structure system, or allowing a self-propelled body to move forward under its own force. Because experimental parameters (including forces and even the mass of the test object) are defined in software, one can define entire ensembles of experiments to run autonomously. CPFD additionally integrates related systems such as water channel speed control, LDV flow speed measurements, and PIV flowfield measurements. The end result is a general-purpose experimental system that opens the door to a vast array of fluid-structure interaction problems. We begin by describing the design and implementation of CPFD, the heart of which is a high-performance force-feedback control system. Precise measurement of time-varying forces (including removing effects of the test object's inertia) is more critical here than in typical robotic force-feedback applications. CPFD is based on an integration of ideas from control theory, fluid dynamics, computer science, electrical engineering, and solid mechanics. We also describe experiments using the CPFD experimental apparatus to study vortex-induced vibration (VIV) and oscillating-airfoil propulsion. We show how CPFD can be used to simulate
Application of fluid-structure coupling to predict the dynamic behavior of turbine components
Energy Technology Data Exchange (ETDEWEB)
Huebner, B; Seidel, U [Voith Hydro Holding GmbH and Co. KG, Alexanderstr. 11, 89522 Heidenheim (Germany); Roth, S, E-mail: bjoern.huebner@voith.co [Laboratory for Hydraulic Machines, EPFL, Avenue de Cour 33 Bis, 1007 Lausanne (Switzerland)
2010-08-15
In hydro turbine design, fluid-structure interaction (FSI) may play an important role. Examples are flow induced inertia and damping effects, vortex induced vibrations in the lock-in vicinity, or hydroelastic instabilities of flows in deforming gaps (e.g. labyrinth seals). In contrast to aeroelasticity, hydroelastic systems require strongly (iteratively) coupled or even monolithic solution procedures, since the fluid mass which is moving with the structure (added-mass effect) is much higher and changes the dynamic behavior of submerged structures considerably. Depending on the mode shape, natural frequencies of a turbine runner in water may be reduced to less than 50% of the corresponding frequencies in air, and flow induced damping effects may become one or two orders of magnitude higher than structural damping. In order to reduce modeling effort and calculation time, the solution strategy has to be adapted precisely to a given application. Hence, depending on the problem to solve, different approximations may apply. Examples are the calculation of natural frequencies and response spectra in water using an acoustic fluid formulation, the determination of flow induced damping effects by means of partitioned FSI including complex turbulent flows, and the identification of hydroelastic instabilities using monolithic coupling of non-linear structural dynamics and water flow.
Comparative analysis for low-mass and low-inertia dynamic balancing of mechanisms
van der Wijk, V.; Demeulenaere, B.; Gosselin, C.M.; Herder, Justus Laurens
2012-01-01
Dynamic balance is an important feature of high speed mechanisms and robotics that need to minimize vibrations of the base. The main disadvantage of dynamic balancing, however, is that it is accompanied with a considerable increase in mass and inertia. Aiming at low-mass and low-inertia dynamic
Collective gyromagnetic ratio and moment of inertia from density-dependent Hartree-Fock calculations
International Nuclear Information System (INIS)
Sprung, D.W.L.; Lie, S.G.; Vallieres, M.; Quentin, P.
1979-01-01
The collective gyromagnetic ratio and moment of inertia of deformed even-even axially symmetric nuclei are calculated in the cranking approximation using wave functions obtained with the Skyrme force S-III. Good agreement is found for gsub(R), while the moment of inertia is about 20% too small. The cranking formula leads to better agreement than the projection method. (Auth.)
Inertia in travel choice : The role of risk aversion and learning
Chorus, C.; Dellaert, B.
2009-01-01
This paper contributes to literature by showing how travellers that make normatively rational choices exhibit inertia during a series of risky choices. Our analyses complement other studies that conceive inertia as the result of boundedly rational or even non-deliberate, habitual decision-making. We
40 CFR 86.1772-99 - Road load power, test weight, and inertia weight class determination.
2010-07-01
... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Road load power, test weight, and inertia weight class determination. 86.1772-99 Section 86.1772-99 Protection of Environment ENVIRONMENTAL... for Light-Duty Vehicles and Light-Duty Trucks § 86.1772-99 Road load power, test weight, and inertia...
Inertia and advance in the organic sector: food education in Denmark
DEFF Research Database (Denmark)
Dahl, Astrid; Kristensen, Niels Heine
2005-01-01
Dahl A, & Kristensen NH (2005): Inertia and advance in the organic sector: food education in Denmark. Chapter in Sociological Perspectives of Organic Agriculture. (Edt.: G. Holt and M. Reed). CABI, UK......Dahl A, & Kristensen NH (2005): Inertia and advance in the organic sector: food education in Denmark. Chapter in Sociological Perspectives of Organic Agriculture. (Edt.: G. Holt and M. Reed). CABI, UK...
Thermal inertia of eclipsing binary asteroids : the role of component shape
Mueller, Michael; van de Weijgaert, Marlies
2015-01-01
Thermal inertia controls the temperature distribution on asteroid surfaces. This is of crucial importance to the Yarkovsky effect and for the planning of spacecraft operations on or near the surface. Additionally, thermal inertia is a sensitive indicator for regolith structure.A uniquely direct way
Calculation of nuclear moment of inertia with proper treatment of pairing interaction
International Nuclear Information System (INIS)
Tazaki, S.; Ando, Y.; Hasegawa, M.
1997-01-01
An attempt to calculate nuclear moments of inertia treating the pairing interaction exactly is reported. As usual, hamiltonian is composed of the Nilsson's singleparticle energies and the pairing interaction, but the eigenstates and the eigenvalues are calculated exactly in a realistic, sufficiently large model space. The method of calculating the moment of inertia is presented. (author)
Kπ=1+ pairing interaction and moments of inertia of superdeformed rotational bands in atomic nuclei
International Nuclear Information System (INIS)
Hamamoto, I.; Nazarewicz, W.
1994-01-01
The effect of the pairing interaction coming from the rotationally induced K π =1 + pair-density on the nuclear moments of inertia is studied. It is pointed out that, contrary to the situation at normal deformations, the inclusion of the K π =1 + pairing may appreciably modify the frequency dependence of the moments of inertia at superdeformed shapes
Lin, Jay; Zhou, Steve; Wei, Wenhui; Pan, Chunshen; Lingohr-Smith, Melissa; Levin, Philip
2016-02-01
Clinical inertia is defined as failure to initiate or intensify therapy despite an inadequate treatment response. We assessed the prevalence and identified the predictors of clinical inertia among patients with type 2 diabetes (T2DM) based on personalized goals. Three hemoglobin A1c (A1C) targets (American Diabetes Association A1C inertia was defined as no intensification of treatment during the response period. Demographic and clinical characteristics were analyzed to identify predictors of treatment intensification. Irrespective of A1C target, the majority of patients with T2DM (70.4 to 72.8%) experienced clinical inertia in the 6 months following the index event, with 5.3 to 6.2% of patients intensifying treatment with insulin. Patients with a lower likelihood of intensification were older, used >1 oral antidiabetes drug during the baseline period, and had an above-target A1C more recently. Treatment intensification was associated with patients who had point-of-service insurance, mental illness, an endocrinologist visit in the baseline period, or higher index A1C. The prevalence of clinical inertia among patients with T2DM in a U.S. managed-care setting is high and has increased over more recent years. Factors predicting increased risk of clinical inertia may help identify "at-risk" populations and assist in developing strategies to improve their management.
Analyzing Effect of System Inertia on Grid Frequency Forecasting Usnig Two Stage Neuro-Fuzzy System
Chourey, Divyansh R.; Gupta, Himanshu; Kumar, Amit; Kumar, Jitesh; Kumar, Anand; Mishra, Anup
2018-04-01
Frequency forecasting is an important aspect of power system operation. The system frequency varies with load-generation imbalance. Frequency variation depends upon various parameters including system inertia. System inertia determines the rate of fall of frequency after the disturbance in the grid. Though, inertia of the system is not considered while forecasting the frequency of power system during planning and operation. This leads to significant errors in forecasting. In this paper, the effect of inertia on frequency forecasting is analysed for a particular grid system. In this paper, a parameter equivalent to system inertia is introduced. This parameter is used to forecast the frequency of a typical power grid for any instant of time. The system gives appreciable result with reduced error.
On the moment of inertia and surface redshift of neutron star
International Nuclear Information System (INIS)
Li Wenfei; Zhang Fengshou; Chen Liewen
2001-01-01
Using temperature, density and isospin dependent nuclear equation of state, the authors calculated the moment of inertia and surface redshift of neutron star by resolving Tolman-Oppenheimer-Volkoff equation. It is found that the moment of inertia and surface redshift strongly depend on the nuclear equation of state. The equation of state with high value of un-compressibility and symmetry energy strength coefficient provides a big moment of inertia, while effective mass of nucleon has almost no effect on moment of inertia. Meanwhile, the equation of state with high value of un-compressibility and effective mass of nucleon provides a big surface redshift, while the symmetry energy strength coefficient has almost no effect on surface redshift of neutron star. The relationship between moment of inertia and mass is also given. By comparing the calculated results with the one obtained semi-empirically from astronomy, the authors find that a softer equation of state can provide a more reasonable result
Distributed Power System Virtual Inertia Implemented by Grid-Connected Power Converters
DEFF Research Database (Denmark)
Fang, Jingyang; Li, Hongchang; Tang, Yi
2018-01-01
Renewable energy sources (RESs), e.g. wind and solar photovoltaics, have been increasingly used to meet worldwide growing energy demands and reduce greenhouse gas emissions. However, RESs are normally coupled to the power grid through fast-response power converters without any inertia, leading...... to decreased power system inertia. As a result, the grid frequency may easily go beyond the acceptable range under severe frequency events, resulting in undesirable load-shedding, cascading failures, or even large-scale blackouts. To address the ever-decreasing inertia issue, this paper proposes the concept...... of distributed power system virtual inertia, which can be implemented by grid-connected power converters. Without modifications of system hardware, power system inertia can be emulated by the energy stored in the dc-link capacitors of grid-connected power converters. By regulating the dc-link voltages...
Semiclassical shell structure of moments of inertia in deformed Fermi systems
International Nuclear Information System (INIS)
Magner, A.G.; Gzhebinsky, A.M.; Sitdikov, A.S.; Khamzin, A.A.; Bartel, J.
2010-01-01
The collective moment of inertia is derived analytically within the cranking model in the adiabatic mean-field approximation at finite temperature. Using the nonperturbative periodic-orbit theory the semiclassical shell-structure components of the collective moment of inertia are obtained for any potential well. Their relation to the free-energy shell corrections are found semiclassically as being given through the shell-structure components of the rigid-body moment of inertia of the statistically equilibrium rotation in terms of short periodic orbits. Shell effects in the moment of inertia disappear exponentially with increasing temperature. For the case of the harmonic-oscillator potential one observes a perfect agreement between semiclassical and quantum shell-structure components of the free energy and the moment of inertia for several critical bifurcation deformations and several temperatures. (author)
Kidney organ donation: developing family practice initiatives to reverse inertia
2010-01-01
Background Kidney transplantation is associated with greater long term survival rates and improved quality of life compared with dialysis. Continuous growth in the number of patients with kidney failure has not been matched by an increase in the availability of kidneys for transplantation. This leads to long waiting lists, higher treatment costs and negative health outcomes. Discussion Misunderstandings, public uncertainty and issues of trust in the medical system, that limit willingness to be registered as a potential donor, could be addressed by community dissemination of information and new family practice initiatives that respond to individuals' personal beliefs and concerns regarding organ donation and transplantation. Summary Tackling both personal and public inertia on organ donation is important for any community oriented kidney donation campaign. PMID:20478042
The Inertia Reaction Force and Its Vacuum Origin
Rueda, Alfonso; Haisch, Bernard
By means of a covariant approach we show that there must be a contribution to the inertial mass and to the inertial reaction force on an accelerated massive object by the zero-point electromagnetic field. This development does not require any detailed model of the accelerated object other than the knowledge that it interacts electromagnetically. It is shown that inertia can indeed be construed as an opposition of the vacuum fields to any change to the uniform state of motion of an object. Interesting insights originating from this result are discussed. It is argued why the proposed existence of a Higgs field in no way contradicts or is at odds with the above statements. The Higgs field is responsible for assigning mass to elementary particles. It is argued that still the underlying reason for the opposition to acceleration that massive objects present requires an explanation. The explanation proposed here fulfills that requirement.
Therapeutic Inertia in the New Landscape of Multiple Sclerosis Care
Directory of Open Access Journals (Sweden)
Gustavo Saposnik
2018-03-01
Full Text Available The landscape of multiple sclerosis (MS treatment is constantly changing. Significant heterogeneity exists in the efficacy and risks associated with these therapies. Therefore, clinicians have the challenge to tailor treatment based on several factors (disease activity level, risk of progression, individual patient preferences and characteristics, personal expertise, etc., to identify the optimal balance between safety and efficacy. However, most clinicians have limited education in decision-making and formal training in risk management. Together, these factors may lead to therapeutic inertia (TI; defined as the absence of treatment initiation or intensification when therapeutic goals are unmet. TI may lead to suboptimal treatments choices, worse clinical outcomes, and more disability. This article provides a succinct overview on factors influencing TI in MS care.
Effects of Roughness and Inertia on Precursors to Frictional Sliding
Robbins, Mark O.; Salerno, K. Michael
2012-02-01
Experiments show that when a PMMA block on a surface is normally loaded and driven by an external shear force, contact at the interface is modified in discrete precursor slips prior to steady state sliding.[1] Our simulations use an atomistic model of a rough two-dimensional block in contact with a flat surface to investigate the evolution of stress and displacement along the contact between surfaces. The talk will show how local and global stress conditions govern the initiation of interfacial cracks as well as the spatial extension of the cracked region. Inertia also plays an important role in determining the number and size of slips before sliding and influences the distribution of stresses at the interface. Finally, the geometry of surface asperities also influences the interfacial evolution and the total friction force. The relationship between the interfacial stress state and rupture velocity will also be discussed. [1] S.M. Rubinstein, G. Cohen and J. Fineberg, PRL 98, 226103 (2007)
The Dynamics of Online Purchase Visits: Inertia or Switching?
Institute of Scientific and Technical Information of China (English)
Zelin Zhang; Xia Wang; Peter T.L.Popkowski Leszczyc; Xiao Zuo
2016-01-01
This paper studies the dynamics of online purchase patterns,focusing on the impact of the channel used on conversion probability,as well as the transition of channel use over time.A novel data set from a major Chinese online travel agency is used for analysis,consisting of four months of data with 24,337 store visits through three types of channels:direct visit,search advertising and referral.Results of a Bayesian multinomial logit model show that the search channel significantly affects consumers' conversion probability,and show a high degree of inertia in channel use.This finding contrasts sharply with suggestions of previous research that most future purchases will converge to the direct-visit channel.
The Early Lunar Orbit and Principal Moments of Inertia
Garrick-Bethell, I.; Zuber, M. T.
2007-12-01
If taken at face value, the principal lunar moments of inertia suggest that the Moon froze in a past tidal and rotational state during a high eccentricity orbit [1]. At this time the Moon may have been in either synchronous rotation or in a 3:2 resonance of spin and mean motion. We have performed further investigations of the plausibility of past high eccentricity lunar orbits on the basis of orbital evolution, the dynamics of entry into any past 3:2 resonance, and tidal dissipation. We have found that the requisite permanent (B-A)/C (where A, B, and C are the principal moments of inertia) for a 3:2 resonance can be achieved in a magma ocean if a density anomaly is present shortly after lunar accretion. In a high eccentricity orbit, tidal dissipation will affect the Moon's ability to develop lithospheric strength. The Moon is presently able to support degree-two loads, while Io, which is approximately the same size as the Moon and strongly heated by tidal dissipation, probably cannot [2]. Therefore, somewhere between the present lunar radioactive heating rate (~1012 W), and Io's observed dissipation (~1014 W), the Moon may develop lithospheric strength. We use 1014 W as a loose upper bound on where freeze-in may begin and find that in a 3:2 resonance tidal dissipation [3] can drop below 1014 W at a = 25 RE and e = 0.17, and the present moments of inertia can be approximately reproduced for lunar values of QM = 475 (where a is the lunar semimajor axis, RE is the Earth radius, and Q is the specific dissipation function). This value of QM is somewhat large, but the biggest problem with a 3:2 resonance that lasts until 25 RE is how to achieve the current low eccentricity synchronous orbit. The required damping cannot be easily achieved unless the Moon is knocked out of a 3:2 resonance by an impactor that would produce a crater approximately 800 km in diameter. In sum, there is no single strong constraint that completely rules out a 3:2 resonance, but it would require a
The Problem of Inertia in a Friedmann Universe
Kazanas, Demosthenes
2012-01-01
In this talk I will discuss the origin of inertia in a curved spacetime, particularly the spatially flat, open and closed Friedmann universes. This is done using Sciama's law of inertial induction, which is based on Mach's principle, and expresses the analogy between the retarded far fields of electrodynamics and those of gravitation. After obtaining covariant expressions for electromagnetic fields due to an accelerating point charge in Friedmann models, we adopt Sciama's law to obtain the inertial force on an accelerating mass $m$ by integrating over the contributions from all the matter in the universe. The resulting inertial force has the form $F = -kma$ where the constant $k < 1 $ depends on the choice of the cosmological parameters such as $\\Omega_{M},\\ \\Omega_{\\Lambda}, $ and $\\Omega_{R}$. The values of $k$ obtained suggest that inertial contribution from dark matter can be the source for the missing part of the inertial force.
Waste canister closure welding using the inertia friction welding process
International Nuclear Information System (INIS)
Klein, R.F.; Siemens, D.H.; Kuruzar, D.L.
1986-02-01
Liquid radioactive waste presently stored in underground tanks is to undergo a vitrifying process which will immobilize it in a solid form. This solid waste will be contained in a stainless steel canister. The canister opening requires a positive seal weld, the properties and thickness of which are at least equal to those of the canister material. This paper describes the inertia friction welding process and a proposed equipment design concept that will provide a positive, reliable, inspectable, and full thickness seal weld while providing easily maintainable equipment, even though the weld is made in a highly contaminated hot cell. All studies and tests performed have shown the concept to be highly feasible. 2 refs., 6 figs
The earth's equatorial principal axes and moments of inertia
Liu, H. S.; Chao, B. F.
1991-01-01
The earth's equatorial principal moments of inertia are given as A and B, where A is less than B, and the corresponding principal axes are given as a and b. Explicit formulas are derived for determining the orientation of a and b axes and the difference B - A using C(22) and S(22), the two gravitational harmonic coefficients of degree 2 and order 2. For the earth, the a axis lies along the (14.93 deg W, 165.07 deg E) diameter, and the b axis lies perpendicular to it along the (75.07 deg E, 104.93 deg W) diameter. The difference B - A is 7.260 x 10 to the -6th MR2. These quantities for other planets are contrasted, and geophysical implications are discussed.
Family physician clinical inertia in glycemic control among patients with type 2 diabetes.
Bralić Lang, Valerija; Bergman Marković, Biserka; Kranjčević, Ksenija
2015-02-05
Many patients with diabetes do not achieve target values. One of the reasons for this is clinical inertia. The correct explanation of clinical inertia requires a conjunction of patient with physician and health care system factors. Our aim was to determine the rate of clinical inertia in treating diabetes in primary care and association of patient, physician, and health care setting factors with clinical inertia. This was a national, multicenter, observational, cross-sectional study in primary care in Croatia. Each family physician (FP) provided professional data and collected clinical data on 15-25 type 2 diabetes (T2DM) patients. Clinical inertia was defined as a consultation in which treatment change based on glycated hemoglobin (HbA1c) levels was indicated but did not occur. A total of 449 FPs (response rate 89.8%) collected data on 10275 patients. Mean clinical inertia per FP was 55.6% (SD ±26.17) of consultations. All of the FPs were clinically inert with some patients, and 9% of the FPs were clinically inert with all patients. The main factors associated with clinical inertia were: higher percentage of HbA1c, oral anti-diabetic drug initiated by diabetologist, increased postprandial glycemia and total cholesterol, physical inactivity of patient, and administration of drugs other than oral antidiabetics. Clinical inertia in treating patients with T2DM is a serious problem. Patients with worse glycemic control and those whose therapy was initiated by a diabetologist experience more clinical inertia. More research on causes of clinical inertia in treating patients with T2DM should be conducted to help achieve more effective diabetes control.
Factors associated with therapeutic inertia in hypertension: validation of a predictive model.
Redón, Josep; Coca, Antonio; Lázaro, Pablo; Aguilar, Ma Dolores; Cabañas, Mercedes; Gil, Natividad; Sánchez-Zamorano, Miguel Angel; Aranda, Pedro
2010-08-01
To study factors associated with therapeutic inertia in treating hypertension and to develop a predictive model to estimate the probability of therapeutic inertia in a given medical consultation, based on variables related to the consultation, patient, physician, clinical characteristics, and level of care. National, multicentre, observational, cross-sectional study in primary care and specialist (hospital) physicians who each completed a questionnaire on therapeutic inertia, provided professional data and collected clinical data on four patients. Therapeutic inertia was defined as a consultation in which treatment change was indicated (i.e., SBP >or= 140 or DBP >or= 90 mmHg in all patients; SBP >or= 130 or DBP >or= 80 in patients with diabetes or stroke), but did not occur. A predictive model was constructed and validated according to the factors associated with therapeutic inertia. Data were collected on 2595 patients and 13,792 visits. Therapeutic inertia occurred in 7546 (75%) of the 10,041 consultations in which treatment change was indicated. Factors associated with therapeutic inertia were primary care setting, male sex, older age, SPB and/or DBP values close to normal, treatment with more than one antihypertensive drug, treatment with an ARB II, and more than six visits/year. Physician characteristics did not weigh heavily in the association. The predictive model was valid internally and externally, with acceptable calibration, discrimination and reproducibility, and explained one-third of the variability in therapeutic inertia. Although therapeutic inertia is frequent in the management of hypertension, the factors explaining it are not completely clear. Whereas some aspects of the consultations were associated with therapeutic inertia, physician characteristics were not a decisive factor.
Mahabaleshwarkar, Rohan; Gohs, Frank; Mulder, Holly; Wilkins, Nick; DeSantis, Andrea; Anderson, William E; Ejzykowicz, Flavia; Rajpathak, Swapnil; Norton, H James
2017-08-01
Our aim was to determine the extent of clinical inertia and the associated patient and provider factors in patients with type 2 diabetes on metformin monotherapy (MM) at a large integrated health care system in the United States. The study cohort included patients with type 2 diabetes aged 18 to 85 years, on MM between January 2009 and September 2013, who experienced MM failure (had an uncontrolled glycosylated hemoglobin [HbA 1c ] reading (≥8.0% [64 mmol/mol]) after at least 90 days of MM). Clinical inertia was defined as absence of treatment intensification with an add-on therapy within 180 days after the MM failure (index date). The impact of patient and provider factors on clinical inertia was determined using generalized estimating equations. The study cohort consisted of 996 patients; 58% were men and 59% were white, with a mean age of 53 (11.8) years. Of these, 49.8% experienced clinical inertia. Lower HbA 1c at index date, absence of liver diseases, absence of renal diseases, and greater provider age were associated with clinical inertia. The clinical inertia rate in a secondary analysis considering HbA 1c inertia. Considerable clinical inertia rates were observed in our real-world patient population, suggesting the need of interventions to reduce clinical inertia in clinical practice. Information about patient and provider factors affecting clinical inertia provided by this study could help healthcare policymakers plan and implement such interventions. Copyright © 2017 Elsevier HS Journals, Inc. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Senatore, Giacomo [Department of Aerospace Engineering, Universita di Pisa, Pisa 56122 (Italy); Davis, Sean; Jacobs, Gustaaf, E-mail: gjacobs@mail.sdsu.edu [Department of Aerospace Engineering and Engineering Mechanics, San Diego State University, San Diego, 92182 California (United States)
2015-03-15
The effect of non-uniformity in bulk particle mass loading on the linear development of a particle-laden shear layer is analyzed by means of a stochastic Eulerian-Eulerian model. From the set of governing equations of the two-fluid model, a modified Rayleigh equation is derived that governs the linear growth of a spatially periodic disturbance. Eigenvalues for this Rayleigh equation are determined numerically using proper conditions at the co-flowing gas and particle interface locations. For the first time, it is shown that non-uniform loading of small-inertia particles (Stokes number (St) <0.2) may destabilize the inviscid mixing layer development as compared to the pure-gas flow. The destabilization is triggered by an energy transfer rate that globally flows from the particle phase to the gas phase. For intermediate St (1 < St < 10), a maximum stabilizing effect is computed, while at larger St, two unstable modes may coexist. The growth rate computations from linear stability analysis are verified numerically through simulations based on an Eulerian-Lagrangian (EL) model based on the inviscid Euler equations and a point particle model. The growth rates found in numerical experiments using the EL method are in very good agreement with growth rates from the linear stability analysis and validate the destabilizing effect induced by the presence of particles with low St.
Seismic analysis of a large LMFBR with fluid-structure interactions
International Nuclear Information System (INIS)
Ma, D.C.
1985-01-01
The seismic analysis of a large LMFBR with many internal components and structures is presented. Both vertical and horizontal seismic excitations are considered. The important hydrodynamic phenomena such as fluid-structure interaction, sloshing, fluid coupling and fluid inertia effects are included in the analysis. The results of this study are discussed in detail. Information which is useful to the design of future reactions under seismic conditions is also given. 4 refs., 12 figs
Energy Technology Data Exchange (ETDEWEB)
Kaothekar, Sachin, E-mail: sackaothekar@gmail.com [Department of Physics, Mahakal Institute of Technology, Ujjain-456664, Madhya Pradesh (India)
2016-08-15
I have studied the effects of finite electron inertia, finite ion Larmor radius (FLR) corrections, and radiative heat-loss function on the thermal instability of an infinite homogeneous, viscous plasma incorporating the effect of thermal conductivity for star formation in interstellar medium (ISM). A general dispersion relation is derived using the normal mode analysis method with the help of relevant linearized perturbation equations of the problem. The wave propagation is discussed for longitudinal and transverse directions to the external magnetic field and the conditions of modified thermal instabilities and stabilities are discussed in different cases. We find that the thermal instability criterion is get modified into radiative instability criterion by inclusion of radiative heat-loss functions with thermal conductivity. The viscosity of medium removes the effect of FLR corrections from the condition of radiative instability. Numerical calculation shows stabilizing effect of heat-loss function, viscosity and FLR corrections, and destabilizing effect of finite electron inertia on the thermal instability. Results carried out in this paper shows that stars are formed in interstellar medium mainly due to thermal instability.
Directory of Open Access Journals (Sweden)
Sachin Kaothekar
2016-08-01
Full Text Available I have studied the effects of finite electron inertia, finite ion Larmor radius (FLR corrections, and radiative heat-loss function on the thermal instability of an infinite homogeneous, viscous plasma incorporating the effect of thermal conductivity for star formation in interstellar medium (ISM. A general dispersion relation is derived using the normal mode analysis method with the help of relevant linearized perturbation equations of the problem. The wave propagation is discussed for longitudinal and transverse directions to the external magnetic field and the conditions of modified thermal instabilities and stabilities are discussed in different cases. We find that the thermal instability criterion is get modified into radiative instability criterion by inclusion of radiative heat-loss functions with thermal conductivity. The viscosity of medium removes the effect of FLR corrections from the condition of radiative instability. Numerical calculation shows stabilizing effect of heat-loss function, viscosity and FLR corrections, and destabilizing effect of finite electron inertia on the thermal instability. Results carried out in this paper shows that stars are formed in interstellar medium mainly due to thermal instability.
2010-07-01
... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Road load power, test weight, inertia... Procedures § 86.129-94 Road load power, test weight, inertia weight class determination, and fuel temperature... duty trucks 1,2,3 Test weightbasis 4,5 Test equivalent test weight(pounds) Inertia weight class(pounds...
On the identifiability of inertia parameters of planar Multi-Body Space Systems
Nabavi-Chashmi, Seyed Yaser; Malaek, Seyed Mohammad-Bagher
2018-04-01
This work describes a new formulation to study the identifiability characteristics of Serially Linked Multi-body Space Systems (SLMBSS). The process exploits the so called "Lagrange Formulation" to develop a linear form of Equations of Motion w.r.t the system Inertia Parameters (IPs). Having developed a specific form of regressor matrix, we aim to expedite the identification process. The new approach allows analytical as well as numerical identification and identifiability analysis for different SLMBSSs' configurations. Moreover, the explicit forms of SLMBSSs identifiable parameters are derived by analyzing the identifiability characteristics of the robot. We further show that any SLMBSS designed with Variable Configurations Joint allows all IPs to be identifiable through comparing two successive identification outcomes. This feature paves the way to design new class of SLMBSS for which accurate identification of all IPs is at hand. Different case studies reveal that proposed formulation provides fast and accurate results, as required by the space applications. Further studies might be necessary for cases where planar-body assumption becomes inaccurate.
Directory of Open Access Journals (Sweden)
Peter eKoval
2016-01-01
Full Text Available Previous studies have linked higher emotional inertia (i.e., a stronger autoregressive slope of emotions with lower well-being. We aimed to replicate these findings, while extending upon previous research by addressing a number of unresolved issues and controlling for potential confounds. Specifically, we report results from two studies (Ns = 100 & 202 examining how emotional inertia, assessed in response to a standardized sequence of emotional stimuli in the lab, correlates with several measures of well-being. The current studies build on previous research by examining how inertia of both positive emotions (PE and negative emotions (NE are related to both positive (e.g., life satisfaction and negative (e.g., depressive symptoms indicators of well-being, while controlling for between-person differences in the mean level and variability of emotions. Our findings replicated previous research and further revealed that a NE inertia was more strongly associated with lower well-being than PE inertia; b emotional inertia correlated more consistently with negative indicators (e.g., depressive symptoms than positive indicators (e.g., life satisfaction of well-being; and c these relationships were independent of individual differences in mean level and variability of emotions. We conclude, in line with recent findings, that higher emotional inertia, particularly of NE, may indicate increased vulnerability to depression.
Koval, Peter; Sütterlin, Stefan; Kuppens, Peter
2015-01-01
Previous studies have linked higher emotional inertia (i.e., a stronger autoregressive slope of emotions) with lower well-being. We aimed to replicate these findings, while extending upon previous research by addressing a number of unresolved issues and controlling for potential confounds. Specifically, we report results from two studies (Ns = 100 and 202) examining how emotional inertia, assessed in response to a standardized sequence of emotional stimuli in the lab, correlates with several measures of well-being. The current studies build on previous research by examining how inertia of both positive emotions (PE) and negative emotions (NE) relates to positive (e.g., life satisfaction) and negative (e.g., depressive symptoms) indicators of well-being, while controlling for between-person differences in the mean level and variability of emotions. Our findings replicated previous research and further revealed that (a) NE inertia was more strongly associated with lower well-being than PE inertia; (b) emotional inertia correlated more consistently with negative indicators (e.g., depressive symptoms) than positive indicators (e.g., life satisfaction) of well-being; and (c) these relationships were independent of individual differences in mean level and variability of emotions. We conclude, in line with recent findings, that higher emotional inertia, particularly of NE, may be an indicator of increased vulnerability to depression.
Thermal inertia mapping of Mars from 60°S to 60°N
Palluconi, Frank Don; Kieffer, Hugh H.
1981-01-01
Twenty-micrometer brightness temperatures are used to derive the thermal inertia for 81% of the Martian surface between latitudes ±60°. These data were acquired by the two Viking Infrared Thermal Mappers in 1977 and 1978 following the two global dust storms of 1977. The spatial resolution used is 2° in latitude by 2° in longitude and the total range in derived inertia is . The distribution of thermal inertia is strongly bimodal with all values of thermal inertia less than being associated with three disjoint bright regions mostly in the northern hemisphere. Sufficient dust is raised in global storms to provide fine material adequate to produce these low-inertia areas but the specific deposition mechanism has not been defined. At the low resolution used, no complete exposures of clean rock were found. There is some tendency for darker material to be associated with higher thermal inertia, although the trend is far from one to one. The distribution of high- and low-inertia areas is sufficiently nonrandom to produce a variation in whole-disk brightness temperature with central meridian longitude. This variation and the change in surface kinetic temperature associated with dust storms are factors in establishing the whole-disk brightness temperature at radio and infrared wavelengths and will be important for those who use Mars as a calibration source.
Impact of clinical inertia on cardiovascular risk factors in patients with diabetes.
Whitford, David L; Al-Anjawi, Hussam A; Al-Baharna, Marwa M
2014-07-01
To determine whether clinical inertia is associated with simpler interventions occurring more often than complex changes and the association between clinical inertia and outcomes. Prevalence of clinical inertia over a 30 month period for hyperglycaemia, hypertension and dyslipidaemia was calculated in a random sample (n=334) of patients attending a diabetes clinic. Comparisons between prevalence of clinical inertia and outcomes for each condition were examined using parametric tests of association. There was less clinical inertia in hyperglycaemia (29% of consultations) compared with LDL (80% of consultations) and systolic BP (68% of consultations). Consultations where therapy was intensified had a greater reduction in risk factor levels than when no change was made. No association was found between treatment intensity scores and changes in HbA1c, LDL or blood pressure over 30 months. Physicians are no more likely to intervene in conditions where simple therapeutic changes are necessary as opposed to complex changes. Greater clinical inertia leads to poorer outcomes. There continues to be substantial clinical inertia in routine clinical practice. Physicians should adopt a holistic approach to cardiovascular risk reduction in patients with diabetes, adhere more closely to established management guidelines and emphasize personal individualized target setting. Copyright © 2013 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.
Development of ABWR inertia-increased reactor internal pump and thicker sleeve nozzle
International Nuclear Information System (INIS)
Takahashi, Shirou; Shiina, Kouji; Matsumura, Seiichi
2002-01-01
The conventional reactor internal pumps (RIPs) in the ABWR have an inertia moment coming from the shafts and Motor-Generator sets, enabling the RIPs to continue running for a few seconds, when a trip of all RIPs event occurs. It is possible to simplify the RIPs' power supply system without affecting the core flow supply when the above event occurs by eliminating M-G sets, if the rotating inertia is increased. This inertia increase due to an additional flywheel, which leads to gains in weight and length, requires the larger diameter nozzle with the thicker sleeve. However, too large a nozzle diameter may change the hydraulic performance. In authors' previous study, the optimum nozzle diameter (492 mm) was selected through 1/5-scale test. In this study, the 492 mm nozzle and the inertia-increased RIP were verified through the full-scale tests. The rotating inertia time constant on coastdown characteristics (behavior of the RIP speed in the event of power loss) for the inertia-increased RIP doubled compared with the current RIP. The casing and the shaft vibration were also confirmed to satisfy the design criteria. Moreover, hydraulic performance and heat increase in the motor casing due to the flywheel were evaluated. The inertia increased RIP with the 492 mm nozzle maintained good performance. (author)
Diagnostic inertia in dyslipidaemia: results of a preventative programme in Spain.
Palazón-Bru, Antonio; Sepehri, Armina; Ramírez-Prado, Dolores; Navarro-Cremades, Felipe; Cortés, Ernesto; Rizo-Baeza, Mercedes; Gil-Guillén, Vicente Francisco
2015-01-01
Others have analysed the relationship between inadequate behaviour by healthcare professionals in the diagnosis of dyslipidaemia (diagnostic inertia) and the history of cardiovascular risk factors. However, since no study has assessed cardiovascular risk scores as associated factors, we carried out a study to quantify diagnostic inertia in dyslipidaemia and to determine if cardiovascular risk scores are associated with this inertia. In the Valencian Community (Spain), a preventive programme (cardiovascular, gynaecologic and vaccination) was started in 2003 inviting persons aged ≥40 years to undergo a health check-up at their health centre. This cross-sectional study examined persons with no known dyslipidaemia seen during the first six months of the programme (n = 16, 905) but whose total cholesterol (TC) was ≥5.17 mmol/L. Diagnostic inertia was defined as lack of follow-up to confirm/discard the dyslipidaemia diagnosis. Other variables included in the analysis were gender, history of cardiovascular risk factors/cardiovascular disease, counselling (diet/exercise), body mass index (BMI), age, blood pressure, fasting blood glucose and lipids. TC was grouped as ≥/Inertia was quantified and the adjusted odds ratios calculated from multivariate models. In the overall sample, the rate of diagnostic inertia was 52% (95% CI [51.2-52.7]); associated factors were TC ≥ 6.20 mmol/L, high or "not measured" BMI, hypertension, smoking and higher values of fasting blood glucose, systolic blood pressure and TC. In the REGICOR sample, the rate of diagnostic inertia was 51.9% (95% CI [51.1-52.7]); associated factors were REGICOR high and high or "not measured" BMI. In the SCORE sample the rate of diagnostic inertia was 51.7% (95% CI [50.9-52.5]); associated factors were SCORE high and high or "not measured" BMI. Diagnostic inertia existed in over half the patients and was associated with a greater cardiovascular risk.
International Nuclear Information System (INIS)
Suwono.
1978-01-01
A linear gate providing a variable gate duration from 0,40μsec to 4μsec was developed. The electronic circuity consists of a linear circuit and an enable circuit. The input signal can be either unipolar or bipolar. If the input signal is bipolar, the negative portion will be filtered. The operation of the linear gate is controlled by the application of a positive enable pulse. (author)
International Nuclear Information System (INIS)
Vretenar, M
2014-01-01
The main features of radio-frequency linear accelerators are introduced, reviewing the different types of accelerating structures and presenting the main characteristics aspects of linac beam dynamics
The Inertia Weight Updating Strategies in Particle Swarm Optimisation Based on the Beta Distribution
Directory of Open Access Journals (Sweden)
Petr Maca
2015-01-01
Full Text Available The presented paper deals with the comparison of selected random updating strategies of inertia weight in particle swarm optimisation. Six versions of particle swarm optimization were analysed on 28 benchmark functions, prepared for the Special Session on Real-Parameter Single Objective Optimisation at CEC2013. The random components of tested inertia weight were generated from Beta distribution with different values of shape parameters. The best analysed PSO version is the multiswarm PSO, which combines two strategies of updating the inertia weight. The first is driven by the temporally varying shape parameters, while the second is based on random control of shape parameters of Beta distribution.
Haro, Helida C.
2010-01-01
The objective of this research effort is to determine the most appropriate, cost efficient, and effective method to utilize for finding moments of inertia for the Uninhabited Aerial Vehicle (UAV) Dryden Remotely Operated Integrated Drone (DROID). A moment is a measure of the body's tendency to turn about its center of gravity (CG) and inertia is the resistance of a body to changes in its momentum. Therefore, the moment of inertia (MOI) is a body's resistance to change in rotation about its CG. The inertial characteristics of an UAV have direct consequences on aerodynamics, propulsion, structures, and control. Therefore, it is imperative to determine the precise inertial characteristics of the DROID.
The influence of electron inertia on the modulational instability of ion-acoustic waves
International Nuclear Information System (INIS)
Parkes, E.J.
1993-01-01
The influence of electron inertia, ion streaming and weak relativistic effects on the modulational instability of ion-acoustic waves in a collisionless unmagnetized plasma is investigated. The derivative expansion method is used to derive a nonlinear Schroedinger equation, from which an instability criterion is deduced. When electron inertia is ignored, ion streaming and weak relativistic effects have little effect on the instability criterion. It is shown that when electron inertia is taken into account, the instability criterion is sensitive to weakly relativistic ion streaming, but not to the ratio of electron mass to ion mass. (Author)
Haro, Helida C.
2010-01-01
The objective of this research effort is to determine the most appropriate, cost efficient, and effective method to utilize for finding moments of inertia for the Uninhabited Aerial Vehicle (UAV) Dryden Remotely Operated Integrated Drone (DROID). A moment is a measure of the body's tendency to turn about its center of gravity (CG) and inertia is the resistance of a body to changes in its momentum. Therefore, the moment of inertia (MOI) is a body's resistance to change in rotation about its CG. The inertial characteristics of an UAV have direct consequences on aerodynamics, propulsion, structures, and control. Therefore, it is imperative to determine the precise inertial characteristics of the DROID.
A Change of Inertia-Supporting the Thrust Vector Control of the Space Launch System
Dziubanek, Adam J.
2012-01-01
The Space Launch System (SLS) is America's next launch vehicle. To utilize the vehicle more economically, heritage hardware from the Space Transportation System (STS) will be used when possible. The Solid Rocket Booster (SRB) actuators could possibly be used in the core stage of the SLS. The dynamic characteristics of the SRB actuator will need to be tested on an Inertia Load Stand (ILS) that has been converted to Space Shuttle Main Engine (SSME). The inertia on the pendulum of the ILS will need to be changed to match the SSME inertia. In this testing environment an SRB actuator can be tested with the equivalent resistence of an SSME.
Inertia and friction welding of aluminum alloy 1100 to type 316 stainless steel
International Nuclear Information System (INIS)
Perkins, M.A.
1979-01-01
The inertia and friction-welding processes were evaluated for joining aluminum alloy 1100-H14 and Type 316 vacuum-induction melted, vacuum-arc remelted (VIM VAR) stainless steel. While both processes consistently produced joints in which the strength exceeded the strength of the aluminum base metal, 100 percent bonding was not reliably achieved with inertia welding. The deficiency points out the need for development of nondestructive testing techniques for this type of joint. Additionally, solid-state volume diffusion did not appear to be a satisfactory explanation for the inertia and friction-welding bonding mechanism
Adverse Selection and Inertia in Health Insurance Markets: When Nudging Hurts.
Handel, Benjamin R
2013-12-01
This paper investigates consumer inertia in health insurance markets, where adverse selection is a potential concern. We leverage a major change to insurance provision that occurred at a large firm to identify substantial inertia, and develop and estimate a choice model that also quantifies risk preferences and ex ante health risk. We use these estimates to study the impact of policies that nudge consumers toward better decisions by reducing inertia. When aggregated, these improved individual-level choices substantially exacerbate adverse selection in our setting, leading to an overall reduction in welfare that doubles the existing welfare loss from adverse selection.
Thermohydrodynamic analysis of cryogenic liquid turbulent flow fluid film bearings
Andres, Luis San
1993-01-01
A thermohydrodynamic analysis is presented and a computer code developed for prediction of the static and dynamic force response of hydrostatic journal bearings (HJB's), annular seals or damper bearing seals, and fixed arc pad bearings for cryogenic liquid applications. The study includes the most important flow characteristics found in cryogenic fluid film bearings such as flow turbulence, fluid inertia, liquid compressibility and thermal effects. The analysis and computational model devised allow the determination of the flow field in cryogenic fluid film bearings along with the dynamic force coefficients for rotor-bearing stability analysis.
Linearization Method and Linear Complexity
Tanaka, Hidema
We focus on the relationship between the linearization method and linear complexity and show that the linearization method is another effective technique for calculating linear complexity. We analyze its effectiveness by comparing with the logic circuit method. We compare the relevant conditions and necessary computational cost with those of the Berlekamp-Massey algorithm and the Games-Chan algorithm. The significant property of a linearization method is that it needs no output sequence from a pseudo-random number generator (PRNG) because it calculates linear complexity using the algebraic expression of its algorithm. When a PRNG has n [bit] stages (registers or internal states), the necessary computational cost is smaller than O(2n). On the other hand, the Berlekamp-Massey algorithm needs O(N2) where N(≅2n) denotes period. Since existing methods calculate using the output sequence, an initial value of PRNG influences a resultant value of linear complexity. Therefore, a linear complexity is generally given as an estimate value. On the other hand, a linearization method calculates from an algorithm of PRNG, it can determine the lower bound of linear complexity.
Directory of Open Access Journals (Sweden)
Costanza Aricò
2018-01-01
Full Text Available The shallow water equations are a mathematical tool widely applied for the simulation of flow routing in rivers and floodplains, as well as for flood inundation mapping. The interest of many researchers has been focused on the study of simplified forms of the original set of equations. One of the most commonly applied simplifications consists of neglecting the inertial terms. The effects of such a choice on the outputs of the simulations of flooding events are controversial and are an important topic of debate. In the present paper, two numerical models recently proposed for the solution of the complete and zero-inertia forms of the shallow water equations, are applied to several unsteady flow routing scenarios. We simulate synthetic and laboratory scenarios of unsteady flow routing, starting from very simple geometries and gradually moving towards complex topographies. Unlike the studies of the range of validity of the zero-inertia model, based on a small perturbation of the linearized flow model, in unsteady flow propagation over irregular topographies, it is more difficult to specify criteria for the applicability of the simplified set of equations. In analyzing the role of the terms in the momentum equations, we try to understand the effect of neglecting the inertial terms in the zero-inertia formulation. We also analyze the computational costs.
Arbitrary Lagrangian-Eulerian method for non-linear problems of geomechanics
International Nuclear Information System (INIS)
Nazem, M; Carter, J P; Airey, D W
2010-01-01
In many geotechnical problems it is vital to consider the geometrical non-linearity caused by large deformation in order to capture a more realistic model of the true behaviour. The solutions so obtained should then be more accurate and reliable, which should ultimately lead to cheaper and safer design. The Arbitrary Lagrangian-Eulerian (ALE) method originated from fluid mechanics, but has now been well established for solving large deformation problems in geomechanics. This paper provides an overview of the ALE method and its challenges in tackling problems involving non-linearities due to material behaviour, large deformation, changing boundary conditions and time-dependency, including material rate effects and inertia effects in dynamic loading applications. Important aspects of ALE implementation into a finite element framework will also be discussed. This method is then employed to solve some interesting and challenging geotechnical problems such as the dynamic bearing capacity of footings on soft soils, consolidation of a soil layer under a footing, and the modelling of dynamic penetration of objects into soil layers.
Slow rotation of a sphere with source at its centre in a viscous fluid
Indian Academy of Sciences (India)
that the QΩ is not negligible, the inertia terms, being non-linear, cannot be altogether omitted; the equation, however, can still be linearized by assuming that the velocity perturbation in the source flow on account of the Stokes flow is small so that the terms containing square of angular velocity can be neglected.
Conceptual design of light ion beam inertia nuclear fusion reactors
International Nuclear Information System (INIS)
1983-07-01
Light ion beam, inertia nuclear fusion system drew attention recently as one of the nuclear fusion systems for power reactors in the history of the research on nuclear fusion. Its beginning seemed to be the judgement that the implosion of fusion fuel pellets with light ions can be realized with the light ions which can be obtained in view of accelerator techniques. Of course, in order to generate practically usable nuclear fusion reaction by this system and maintain it, many technical difficulties must be overcome. This research was carried out for the purpose of discovering such technical problems and searching for their solution. At the time of doing the works, the following policy was adopted. Though their is the difference of fine and rough, the design of a whole reactor system is performed conformably. In order to make comparison with other reactor types and nuclear fusion systems, the design is carried out as the power plant of about one million kWe output. As the extent of the design, the works at conceptual design stage are performed to present the concept of design which satisfies the required function. Basically, the design is made from conservative standpoint. This research of design was started in 1981, and in fiscal 1982, the mutual adjustment among the design of respective parts was performed on the basis of the results in 1981, and the possible revision and new proposal were investigated. (Kako, I.)
Cantilever Beam Natural Frequencies in Centrifugal Inertia Field
Jivkov, V. S.; Zahariev, E. V.
2018-03-01
In the advanced mechanical science the well known fact is that the gravity influences on the natural frequencies and modes even for the vertical structures and pillars. But, the condition that should be fulfilled in order for the gravity to be taken into account is connected with the ration between the gravity value and the geometrical cross section inertia. The gravity is related to the earth acceleration but for moving structures there exist many other acceleration exaggerated forces and such are forces caused by the centrifugal accelerations. Large rotating structures, as wind power generators, chopper wings, large antennas and radars, unfolding space structures and many others are such examples. It is expected, that acceleration based forces influence on the structure modal and frequency properties, which is a subject of the present investigations. In the paper, rotating beams are subject to investigations and modal and frequency analysis is carried out. Analytical dependences for the natural resonances are derived and their dependences on the angular velocity and centrifugal accelerations are derived. Several examples of large rotating beams with different orientations of the rotating shaft are presented. Numerical experiments are conducted. Time histories of the beam tip deflections, that depict the beam oscillations are presented.
Geometrodynamic steering principle reveals the determiners of inertia
International Nuclear Information System (INIS)
Wheeler, J.A.
1988-01-01
What shall the authors need to grasp the essence of quantum gravity? One requirement, at least, is essential: to understand the steering principle of classical geometrodynamics. The authors outline here the physical content of that steering principle - heat of the so-called initial value problem - in its J.W. York, Jr. formulation. The central idea epitomizes itself in a single simple sentence: Mass-energy there determines inertia here. They spell out this steering principle both in its precise form and in its poor man's version. At both levels of analysis considerations of physics and mathematics alike require that the effective mass-energy of gravity waves must make itself felt on the spacetime geometry - and therefore on the gyro-defined local inertial frame of reference - on the same level as matter itself. Additional to the (mass)/(distance) Newtonian potential so familiar as measure of the effect of a nearby mass on the local frame is the Thirring and Lense gravitomagnetic potential, proportional to (angular momentum) x (distance vector)/(distance). The recent proposal of Ciufolini for a dual laser-ranged LAGEOS satellite to detect the thus-predicted gravitomagnetism of the earth is briefly described
Said-Houari, Belkacem
2017-01-01
This self-contained, clearly written textbook on linear algebra is easily accessible for students. It begins with the simple linear equation and generalizes several notions from this equation for the system of linear equations and introduces the main ideas using matrices. It then offers a detailed chapter on determinants and introduces the main ideas with detailed proofs. The third chapter introduces the Euclidean spaces using very simple geometric ideas and discusses various major inequalities and identities. These ideas offer a solid basis for understanding general Hilbert spaces in functional analysis. The following two chapters address general vector spaces, including some rigorous proofs to all the main results, and linear transformation: areas that are ignored or are poorly explained in many textbooks. Chapter 6 introduces the idea of matrices using linear transformation, which is easier to understand than the usual theory of matrices approach. The final two chapters are more advanced, introducing t...
Koval, Peter; Butler, Emily A; Hollenstein, Tom; Lanteigne, Dianna; Kuppens, Peter
2015-01-01
The tendency for emotions to be predictable over time, labelled emotional inertia, has been linked to low well-being and is thought to reflect impaired emotion regulation. However, almost no studies have examined how emotion regulation relates to emotional inertia. We examined the effects of cognitive reappraisal and expressive suppression on the inertia of behavioural, subjective and physiological measures of emotion. In Study 1 (N = 111), trait suppression was associated with higher inertia of negative behaviours. We replicated this finding experimentally in Study 2 (N = 186). Furthermore, in Study 2, instructed suppressors and reappraisers both showed higher inertia of positive behaviours, and reappraisers displayed higher inertia of heart rate. Neither suppression nor reappraisal were associated with the inertia of subjective feelings in either study. Thus, the effects of suppression and reappraisal on the temporal dynamics of emotions depend on the valence and emotional response component in question.
Energy Technology Data Exchange (ETDEWEB)
Melin, Alexander M. [ORNL; Zhang, Yichen [University of Tennessee, Knoxville (UTK), Department of Electrical Engineering and Computer Science; Djouadi, Seddik [University of Tennessee, Knoxville (UTK), Department of Electrical Engineering and Computer Science; Olama, Mohammed M. [ORNL
2017-04-01
In this paper, a model reference control based inertia emulation strategy is proposed. Desired inertia can be precisely emulated through this control strategy so that guaranteed performance is ensured. A typical frequency response model with parametrical inertia is set to be the reference model. A measurement at a specific location delivers the information of disturbance acting on the diesel-wind system to the referencemodel. The objective is for the speed of the diesel-wind system to track the reference model. Since active power variation is dominantly governed by mechanical dynamics and modes, only mechanical dynamics and states, i.e., a swing-engine-governor system plus a reduced-order wind turbine generator, are involved in the feedback control design. The controller is implemented in a three-phase diesel-wind system feed microgrid. The results show exact synthetic inertia is emulated, leading to guaranteed performance and safety bounds.
Semiclassical moment of inertia shell-structure within the phase-space approach
International Nuclear Information System (INIS)
Gorpinchenko, D V; Magner, A G; Bartel, J; Blocki, J P
2015-01-01
The moment of inertia for nuclear collective rotations is derived within a semiclassical approach based on the cranking model and the Strutinsky shell-correction method by using the non-perturbative periodic-orbit theory in the phase-space variables. This moment of inertia for adiabatic (statistical-equilibrium) rotations can be approximated by the generalized rigid-body moment of inertia accounting for the shell corrections of the particle density. A semiclassical phase-space trace formula allows us to express the shell components of the moment of inertia quite accurately in terms of the free-energy shell corrections for integrable and partially chaotic Fermi systems, which is in good agreement with the corresponding quantum calculations. (paper)
Don't just do something, stand there! The value and art of deliberate clinical inertia.
Keijzers, Gerben; Cullen, Louise; Egerton-Warburton, Diana; Fatovich, Daniel M
2018-04-01
It can be difficult to avoid unnecessary investigations and treatments, which are a form of low-value care. Yet every intervention in medicine has potential harms, which may outweigh the potential benefits. Deliberate clinical inertia is the art of doing nothing as a positive response. This paper provides suggestions on how to incorporate deliberate clinical inertia into our daily clinical practice, and gives an overview of current initiatives such as 'Choosing Wisely' and the 'Right Care Alliance'. The decision to 'do nothing' can be complex due to competing factors, and barriers to implementation are highlighted. Several strategies to promote deliberate clinical inertia are outlined, with an emphasis on shared decision-making. Preventing medical harm must become one of the pillars of modern health care and the art of not intervening, that is, deliberate clinical inertia, can be a novel patient-centred quality indicator to promote harm reduction. © 2018 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.
Patient inertia and the status quo bias: when an inferior option is preferred.
Suri, Gaurav; Sheppes, Gal; Schwartz, Carey; Gross, James J
2013-09-01
Medical noncompliance is a major public-health problem. One potential source of this noncompliance is patient inertia. It has been hypothesized that one cause of patient inertia might be the status quo bias-which is the tendency to select the default choice among a set of options. To test this hypothesis, we created a laboratory analogue of the decision context that frequently occurs in situations involving patient inertia, and we examined whether participants would stay with a default option even when it was clearly inferior to other available options. Specifically, in Studies 1 and 2, participants were given the option to reduce their anxiety while waiting for an electric shock. When doing nothing was the status quo option, participants frequently did not select the option that would reduce their anxiety. In Study 3, we demonstrated a simple way to overcome status quo bias in a context relevant to patient inertia.
Characterizing Center of Mass and Moment of Inertia of Soldiers' Loads Packed for Combat
National Research Council Canada - National Science Library
Hasselquist, Leif; Bensel, Carolyn K; Norton, Karen; Piscitelle, Louis; Schiffman, Jeffrey M
2004-01-01
...) location and moment of inertia (MOI) may be influenced in combat load packing. In addition, the physical properties of the combat loads were compared to the properties of a laboratory fabricated backpack...
DEFF Research Database (Denmark)
Rezkalla, Michel M.N.; Zecchino, Antonio; Pertl, Michael
2016-01-01
The displacement of conventional generation by converter connected resources reduces the available rotational inertia in the power system, which leads to faster frequency dynamics and consequently a less stable frequency behavior. Virtual inertia, employing energy storage systems, could be used...... of adjusting the battery charging process (i.e., power flow) according to pre-defined algorithms. On the other hand, in case of islanded operation (i.e., low inertia), some of the EV's technical constraints might cause oscillations. This study presents two control algorithms which show that the EVs are capable...... of providing virtual inertia support. The first controller employs a traditional droop control, while the second one is equipped with an innovative control algorithm to eliminate likely oscillations. It is shown that, the proposed innovative control algorithm compared to the traditional droop control, assures...
Cooperation is enhanced by inhomogeneous inertia in spatial prisoner's dilemma game
Chang, Shuhua; Zhang, Zhipeng; Wu, Yu'e.; Xie, Yunya
2018-01-01
Inertia is an important factor that cannot be ignored in the real world for some lazy individuals in the process of decision making. In this work, we introduce a simple classification mechanism of strategy changing in evolutionary prisoner's dilemma games on different topologies. In this model, a part of players update their strategies according to not only the payoff difference, but also the inertia factor, which makes nodes heterogeneous and the system inhomogeneous. Moreover, we also study the impact of the number of neighbors on the evolution of cooperation. The results show that the evolution of cooperation will be promoted to a high level when the inertia factor and the inhomogeneous system are combined. In addition, we find that the more neighbors one player has, the higher density of cooperators is sustained in the optimal position. This work could be conducive to understanding the emergence and persistence of cooperative behavior caused by the inertia factor in reality.
Inertia and ion Landau damping of low-frequency magnetohydrodynamical modes in tokamaks
International Nuclear Information System (INIS)
Bondeson, A.; Chu, M.S.
1996-01-01
The inertia and Landau damping of low-frequency magnetohydrodynamical modes are investigated using the drift-kinetic energy principle for the motion along the magnetic field. Toroidal trapping of the ions decreases the Landau damping and increases the inertia for frequencies below (r/R) 1/2 v thi /qR. The theory is applied to toroidicity-induced Alfvacute en eigenmodes and to resistive wall modes in rotating plasmas. An explanation of the beta-induced Alfvacute en eigenmode is given in terms of the Pfirsch endash Schlueter-like enhancement of inertia at low frequency. The toroidal inertia enhancement also increases the effects of plasma rotation on resistive wall modes. copyright 1996 American Institute of Physics
Drazin, Philip
1987-01-01
Outlines the contents of Volume II of "Principia" by Sir Isaac Newton. Reviews the contributions of subsequent scientists to the physics of fluid dynamics. Discusses the treatment of fluid mechanics in physics curricula. Highlights a few of the problems of modern research in fluid dynamics. Shows that problems still remain. (CW)
Linear mode conversion in a toroidal plasma
International Nuclear Information System (INIS)
Hellsten, T.
1980-05-01
Linear mode conversion at the perpendicular ion cyclotron resonance has been treated for an axially symmetric toroidal plasma. The mode conversion appears between a fast electromagnetic wave and a slow-quasi electrostatic wave, due to finite electron inertia. The problem reduces to the Orr-Sommerfeld equation where the coefficients determining the reflectron, transmission and conversion are functions of the arc length along a poloidal intersection of the resonance surface. These coefficients can be determined from eigenfunctions of an ordinary differential equation. (author)
Stoll, R R
1968-01-01
Linear Algebra is intended to be used as a text for a one-semester course in linear algebra at the undergraduate level. The treatment of the subject will be both useful to students of mathematics and those interested primarily in applications of the theory. The major prerequisite for mastering the material is the readiness of the student to reason abstractly. Specifically, this calls for an understanding of the fact that axioms are assumptions and that theorems are logical consequences of one or more axioms. Familiarity with calculus and linear differential equations is required for understand
[The concentration of ionized and total calcium in the blood of female dogs with uterine inertia].
Kraus, A; Schwab, A
1990-12-01
Blood values of calcium, inorganic phosphate and magnesium were estimated in 26 bitches one day before parturition, on the day of parturition and daily for 6 days post partum. In 17 of these 26 animals the diagnosis was dystocia because of uterine inertia. A comparison of calcium levels between those bitches giving birth spontaneously and those requiring assistance gave no indication that blood calcium deficiency was the cause of uterine inertia.
Effect on the variation of the moment of inertia in band K=1/2
International Nuclear Information System (INIS)
Liu Yanxin; Yu Shaoying; Inner Mongolia Univ. for Nationalities, Tongliao; Chinese Academy of Sciences, Beijing
2004-01-01
The effect on the variation of the moment of inertia in band 171 Yb[521]1/2 is investigated using the particle number conserving (PNC) method for treating the cranked shell model with monopole and Y 20 quadrupole pairing interactions. The experimental moments of inertia of 171 Yb[521]1/2 (signature α=±1/2) and the blocking effect of proton are reproduced well by the PNC calculation, in which no free parameter is involved. (authors)
Nuclear moments of inertia inferred from wobbling motion in the triaxial superdeformed nuclei
International Nuclear Information System (INIS)
Matsuzaki, Masayuki; Shimizu, Yoshifumi R.; Matsuyanagi, Kenichi
2003-01-01
The three moments of inertia associated with the wobbling mode built on the triaxial superdeformed states in Lu-Hf region are investigated by means of the cranked shell model plus random-phase approximation to the configurations with aligned quasiparticle(s). The result indicates that it is crucial to take into account the direct contribution to the moments of inertia from the aligned quasiparticle(s)so as to realize T x > T y in positive-γ shapes. (author)
Spin alignment and collective moment of inertia of the basic rotational band in the cranking model
International Nuclear Information System (INIS)
Tanaka, Yoshihide
1982-01-01
By making an attempt to separate the intrinsic particle and collective rotational motions in the cranking model, the spin alignment and the collective moment of inertia characterizing the basic rotational bands are defined, and are investigated by using a simple i sub(13/2) shell model. The result of the calculation indicates that the collective moment of inertia decreases under the presence of the quasiparticles which are responsible for the increase of the spin alignment of the band. (author)
Particle Swarm Optimization with Various Inertia Weight Variants for Optimal Power Flow Solution
Directory of Open Access Journals (Sweden)
Prabha Umapathy
2010-01-01
Full Text Available This paper proposes an efficient method to solve the optimal power flow problem in power systems using Particle Swarm Optimization (PSO. The objective of the proposed method is to find the steady-state operating point which minimizes the fuel cost, while maintaining an acceptable system performance in terms of limits on generator power, line flow, and voltage. Three different inertia weights, a constant inertia weight (CIW, a time-varying inertia weight (TVIW, and global-local best inertia weight (GLbestIW, are considered with the particle swarm optimization algorithm to analyze the impact of inertia weight on the performance of PSO algorithm. The PSO algorithm is simulated for each of the method individually. It is observed that the PSO algorithm with the proposed inertia weight yields better results, both in terms of optimal solution and faster convergence. The proposed method has been tested on the standard IEEE 30 bus test system to prove its efficacy. The algorithm is computationally faster, in terms of the number of load flows executed, and provides better results than other heuristic techniques.
Magnetic moment of inertia within the torque-torque correlation model.
Thonig, Danny; Eriksson, Olle; Pereiro, Manuel
2017-04-19
An essential property of magnetic devices is the relaxation rate in magnetic switching which strongly depends on the energy dissipation. This is described by the Landau-Lifshitz-Gilbert equation and the well known damping parameter, which has been shown to be reproduced from quantum mechanical calculations. Recently the importance of inertia phenomena have been discussed for magnetisation dynamics. This magnetic counterpart to the well-known inertia of Newtonian mechanics, represents a research field that so far has received only limited attention. We present and elaborate here on a theoretical model for calculating the magnetic moment of inertia based on the torque-torque correlation model. Particularly, the method has been applied to bulk itinerant magnets and we show that numerical values are comparable with recent experimental measurements. The theoretical analysis shows that even though the moment of inertia and damping are produced by the spin-orbit coupling, and the expression for them have common features, they are caused by very different electronic structure mechanisms. We propose ways to utilise this in order to tune the inertia experimentally, and to find materials with significant inertia dynamics.
Effectiveness and clinical inertia in the management of hypertension in patients in Colombia.
Machado-Duque, Manuel Enrique; Ramírez-Valencia, Diana Marcela; Medina-Morales, Diego Alejandro; Machado-Alba, Jorge Enrique
2015-11-01
Determine the effectiveness of treatment and the frequency of clinical inertia in the management of hypertension in Colombian patients. A retrospective study with prospective follow-up of individuals on antihypertensive medication who were treated on medical consultation for 1 year was conducted in 20 Colombian cities. Clinical inertia was considered when no modification of therapy occurred despite not achieving control goals. A total of 355 hypertensive patients were included. From a total of 1142 consultations, therapy was effective in 81.7% of cases. In 18.3% of the cases, the control goal was not achieved, and of these, 81.8% were considered clinical inertia. A logistic regression showed that the use of antidiabetics (odds ratio: 2.31; 95% confidence interval: 1.290-4.167; P = .008) was statistically associated with an increased risk of clinical inertia. With a determination of the frequency of inertia and the high effectiveness of antihypertensive treatment, valuable information can be provided to understand the predictors of clinical inertia. Copyright © 2015 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.
Effect of moment of inertia to H type vertical axis wind turbine aerodynamic performance
International Nuclear Information System (INIS)
Yang, C X; Li, S T
2013-01-01
The main aerodynamic performances (out power out power coefficient torque torque coefficient and so on) of H type Vertical Axis wind Turbine (H-VAWT) which is rotating machinery will be impacted by moment of inertia. This article will use NACA0018 airfoil profile to analyze that moment of inertia through impact performance of H type VAWT by utilizing program of Matlab and theory of Double-Multiple Streamtube. The results showed that the max out power coefficient was barely impacted when moment of inertia is changed in a small area,but the lesser moment of inertia's VAWT needs a stronger wind velocity to obtain the max out power. The lesser moment of inertia's VAWT has a big out power coefficient, torque coefficient and out power before it gets to the point of max out power coefficient. Out power coefficient, torque and torque coefficient will obviously change with wind velocity increased for VAWT of the lesser moment of inertia
Emotional inertia and external events: The roles of exposure, reactivity, and recovery.
Koval, Peter; Brose, Annette; Pe, Madeline L; Houben, Marlies; Erbas, Yasemin; Champagne, Dominique; Kuppens, Peter
2015-10-01
Increased moment-to-moment predictability, or inertia, of negative affect has been identified as an important dynamic marker of psychological maladjustment, and increased vulnerability to depression in particular. However, little is known about the processes underlying emotional inertia. The current article examines how the emotional context, and people's responses to it, are related to emotional inertia. We investigated how individual differences in the inertia of negative affect (NA) are related to individual differences in exposure, reactivity, and recovery from emotional events, in daily life (assessed using experience sampling) as well as in the lab (assessed using an emotional film-clip task), among 200 participants commencing their first year of tertiary education. This dual-method approach allowed us to assess affective responding on different timescales, and in response to standardized as well as idiographic emotional stimuli. Our most consistent finding, across both methods, was that heightened NA inertia is related to decreased NA recovery following negative stimuli, suggesting that higher levels of inertia may be mostly driven by impairments in affect repair following negative events. (c) 2015 APA, all rights reserved).
Martínez, G M; Rennó, N; Fischer, E; Borlina, C S; Hallet, B; de la Torre Juárez, M; Vasavada, A R; Ramos, M; Hamilton, V; Gomez-Elvira, J; Haberle, R M
2014-08-01
The analysis of the surface energy budget (SEB) yields insights into soil-atmosphere interactions and local climates, while the analysis of the thermal inertia ( I ) of shallow subsurfaces provides context for evaluating geological features. Mars orbital data have been used to determine thermal inertias at horizontal scales of ∼10 4 m 2 to ∼10 7 m 2 . Here we use measurements of ground temperature and atmospheric variables by Curiosity to calculate thermal inertias at Gale Crater at horizontal scales of ∼10 2 m 2 . We analyze three sols representing distinct environmental conditions and soil properties, sol 82 at Rocknest (RCK), sol 112 at Point Lake (PL), and sol 139 at Yellowknife Bay (YKB). Our results indicate that the largest thermal inertia I = 452 J m -2 K -1 s -1/2 (SI units used throughout this article) is found at YKB followed by PL with I = 306 and RCK with I = 295. These values are consistent with the expected thermal inertias for the types of terrain imaged by Mastcam and with previous satellite estimations at Gale Crater. We also calculate the SEB using data from measurements by Curiosity's Rover Environmental Monitoring Station and dust opacity values derived from measurements by Mastcam. The knowledge of the SEB and thermal inertia has the potential to enhance our understanding of the climate, the geology, and the habitability of Mars.
Solow, Daniel
2014-01-01
This text covers the basic theory and computation for a first course in linear programming, including substantial material on mathematical proof techniques and sophisticated computation methods. Includes Appendix on using Excel. 1984 edition.
Liesen, Jörg
2015-01-01
This self-contained textbook takes a matrix-oriented approach to linear algebra and presents a complete theory, including all details and proofs, culminating in the Jordan canonical form and its proof. Throughout the development, the applicability of the results is highlighted. Additionally, the book presents special topics from applied linear algebra including matrix functions, the singular value decomposition, the Kronecker product and linear matrix equations. The matrix-oriented approach to linear algebra leads to a better intuition and a deeper understanding of the abstract concepts, and therefore simplifies their use in real world applications. Some of these applications are presented in detailed examples. In several ‘MATLAB-Minutes’ students can comprehend the concepts and results using computational experiments. Necessary basics for the use of MATLAB are presented in a short introduction. Students can also actively work with the material and practice their mathematical skills in more than 300 exerc...
Berberian, Sterling K
2014-01-01
Introductory treatment covers basic theory of vector spaces and linear maps - dimension, determinants, eigenvalues, and eigenvectors - plus more advanced topics such as the study of canonical forms for matrices. 1992 edition.
Searle, Shayle R
2012-01-01
This 1971 classic on linear models is once again available--as a Wiley Classics Library Edition. It features material that can be understood by any statistician who understands matrix algebra and basic statistical methods.
Christofilos, N.C.; Polk, I.J.
1959-02-17
Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.
International Nuclear Information System (INIS)
Auluck, S.K.H.
2002-01-01
Snowplow shocks are supersonic flows in plasmas driven by a magnetic piston, in which the material impacted by the piston 'sticks' to it, resulting in accretion of the plasma near the piston. The density front and the magnetic piston move together as a single structure. A typical example of a snowplow shock is the plasma focus sheath. When normally neglected electron-inertia (EI) terms in the fluid model of the plasma are taken into account, a time scale ω p -1 and a space scale cω p -1 are introduced which are negligible in the bulk of the plasma but are non-negligible in a transition region between the no-plasma region and the dense plasma. As a result 'no-plasma' initial conditions are not valid for the fluid equations obtained by neglecting EI. A resonant coupling between two electron plasma modes via the Hall term is shown to result in spontaneous generation of axial magnetic field and rotation even in the presence of perfect azimuthal symmetry in the low density precursor plasma formed before the ideal plasma phase. Related physics issues such as spontaneous symmetry breaking mechanism are discussed
The effect of directional inertias added to pelvis and ankle on gait
2013-01-01
Background Gait training robots should display a minimum added inertia in order to allow normal walking. The effect of inertias in specific directions is yet unknown. We set up two experiments to assess the effect of inertia in anteroposterior (AP) direction to the ankle and AP and mediolateral (ML) direction to the pelvis. Methods We developed an experimental setup to apply inertia in forward backward and or sideways directions. In two experiments nine healthy subjects walked on a treadmill at 1.5 km/h and 4.5 km/h with no load and with AP loads of 0.3, 1.55 and 3.5 kg to the left ankle in the first experiment and combinations of AP and ML loads on the pelvis (AP loads 0.7, 4.3 and 10.2 kg; ML loads 0.6, 2.3 and 5.3 kg). We recorded metabolic rate, EMG of major leg muscles, gait parameters and kinematics. Results & discussion Adding 1.55 kg or more inertia to the ankle in AP direction increases the pelvis acceleration and decreases the foot acceleration in AP direction both at speeds of 4.5 km/h. Adding 3.5 kg of inertia to the ankle also increases the swing time as well as AP motions of the pelvis and head-arms-trunk (HAT) segment. Muscle activity remains largely unchanged. Adding 10.2 kg of inertia to the pelvis in AP direction causes a significant decrease of the pelvis and HAT segment motions, particularly at high speeds. Also the sagittal back flexion increases. Lower values of AP inertia and ML inertias up to 5.3 kg had negligible effect. In general the found effects are larger at high speeds. Conclusions We found that inertia up to 2 kg at the ankle or 6 kg added to the pelvis induced significant changes, but since these changes were all within the normal inter subject variability we considered these changes as negligible for application as rehabilitation robotics and assistive devices. PMID:23597391
International Nuclear Information System (INIS)
Anon.
1991-01-01
Fluids engineering has played an important role in many applications, from ancient flood control to the design of high-speed compact turbomachinery. New applications of fluids engineering, such as in high-technology materials processing, biotechnology, and advanced combustion systems, have kept up unwaining interest in the subject. More accurate and sophisticated computational and measurement techniques are also constantly being developed and refined. On a more fundamental level, nonlinear dynamics and chaotic behavior of fluid flow are no longer an intellectual curiosity and fluid engineers are increasingly interested in finding practical applications for these emerging sciences. Applications of fluid technology to new areas, as well as the need to improve the design and to enhance the flexibility and reliability of flow-related machines and devices will continue to spur interest in fluids engineering. The objectives of the present seminar were: to exchange current information on arts, science, and technology of fluids engineering; to promote scientific cooperation between the fluids engineering communities of both nations, and to provide an opportunity for the participants and their colleagues to explore possible joint research programs in topics of high priority and mutual interest to both countries. The Seminar provided an excellent forum for reviewing the current state and future needs of fluids engineering for the two nations. With the Seminar ear-marking the first formal scientific exchange between Korea and the United States in the area of fluids engineering, the scope was deliberately left broad and general
Energy Technology Data Exchange (ETDEWEB)
Boualit, A.; Boualit, S. [Unite de recherche appliquee en energies renouvelables, Ghardaia (Algeria); Zeraibi, N. [Universite de Boumerdes, Faculte des hydrocarbures dept. Transport et equipement, Boumerdes (Algeria); Amoura, M. [Universite des Sciences et de la Technologie Houari Boumedienne, Faculte de Physique, Dept. Energetique, Alger (Algeria)
2011-01-15
The thermal development of the hydrodynamically developing laminar flow of a viscoplastic fluid (fluid of Bingham) between two plane plates maintained at a constant temperature has been studied numerically. This analysis has shown the effect caused by inertia and the rheological behaviour of the fluid on the velocity, pressure and temperature fields. The effects of Bingham and Peclet numbers on the Nusselt values with the inclusion of viscous dissipation are also discussed. (authors)
Revisiting the Landau fluid closure.
Hunana, P.; Zank, G. P.; Webb, G. M.; Adhikari, L.
2017-12-01
Advanced fluid models that are much closer to the full kinetic description than the usual magnetohydrodynamic description are a very useful tool for studying astrophysical plasmas and for interpreting solar wind observational data. The development of advanced fluid models that contain certain kinetic effects is complicated and has attracted much attention over the past years. Here we focus on fluid models that incorporate the simplest possible forms of Landau damping, derived from linear kinetic theory expanded about a leading-order (gyrotropic) bi-Maxwellian distribution function f_0, under the approximation that the perturbed distribution function f_1 is gyrotropic as well. Specifically, we focus on various Pade approximants to the usual plasma response function (and to the plasma dispersion function) and examine possibilities that lead to a closure of the linear kinetic hierarchy of fluid moments. We present re-examination of the simplest Landau fluid closures.
CISM Course on Rotating Fluids
1992-01-01
The volume presents a comprehensive overview of rotation effects on fluid behavior, emphasizing non-linear processes. The subject is introduced by giving a range of examples of rotating fluids encountered in geophysics and engineering. This is then followed by a discussion of the relevant scales and parameters of rotating flow, and an introduction to geostrophic balance and vorticity concepts. There are few books on rotating fluids and this volume is, therefore, a welcome addition. It is the first volume which contains a unified view of turbulence in rotating fluids, instability and vortex dynamics. Some aspects of wave motions covered here are not found elsewhere.
Olive, David J
2017-01-01
This text covers both multiple linear regression and some experimental design models. The text uses the response plot to visualize the model and to detect outliers, does not assume that the error distribution has a known parametric distribution, develops prediction intervals that work when the error distribution is unknown, suggests bootstrap hypothesis tests that may be useful for inference after variable selection, and develops prediction regions and large sample theory for the multivariate linear regression model that has m response variables. A relationship between multivariate prediction regions and confidence regions provides a simple way to bootstrap confidence regions. These confidence regions often provide a practical method for testing hypotheses. There is also a chapter on generalized linear models and generalized additive models. There are many R functions to produce response and residual plots, to simulate prediction intervals and hypothesis tests, to detect outliers, and to choose response trans...
International Nuclear Information System (INIS)
Alcaraz, J.
2001-01-01
After several years of study e''+ e''- linear colliders in the TeV range have emerged as the major and optimal high-energy physics projects for the post-LHC era. These notes summarize the present status form the main accelerator and detector features to their physics potential. The LHC era. These notes summarize the present status, from the main accelerator and detector features to their physics potential. The LHC is expected to provide first discoveries in the new energy domain, whereas an e''+ e''- linear collider in the 500 GeV-1 TeV will be able to complement it to an unprecedented level of precision in any possible areas: Higgs, signals beyond the SM and electroweak measurements. It is evident that the Linear Collider program will constitute a major step in the understanding of the nature of the new physics beyond the Standard Model. (Author) 22 refs
Edwards, Harold M
1995-01-01
In his new undergraduate textbook, Harold M Edwards proposes a radically new and thoroughly algorithmic approach to linear algebra Originally inspired by the constructive philosophy of mathematics championed in the 19th century by Leopold Kronecker, the approach is well suited to students in the computer-dominated late 20th century Each proof is an algorithm described in English that can be translated into the computer language the class is using and put to work solving problems and generating new examples, making the study of linear algebra a truly interactive experience Designed for a one-semester course, this text adopts an algorithmic approach to linear algebra giving the student many examples to work through and copious exercises to test their skills and extend their knowledge of the subject Students at all levels will find much interactive instruction in this text while teachers will find stimulating examples and methods of approach to the subject
On the role of micro-inertia in enriched continuum mechanics.
Madeo, Angela; Neff, Patrizio; Aifantis, Elias C; Barbagallo, Gabriele; d'Agostino, Marco Valerio
2017-02-01
In this paper, the role of gradient micro-inertia terms [Formula: see text] and free micro-inertia terms [Formula: see text] is investigated to unveil their respective effects on the dynamic behaviour of band-gap metamaterials. We show that the term [Formula: see text] alone is only able to disclose relatively simplified dispersive behaviour. On the other hand, the term [Formula: see text] alone describes the full complex behaviour of band-gap metamaterials. A suitable mixing of the two micro-inertia terms allows us to describe a new feature of the relaxed-micromorphic model, i.e. the description of a second band-gap occurring for higher frequencies. We also show that a split of the gradient micro-inertia [Formula: see text], in the sense of Cartan-Lie decomposition of matrices, allows us to flatten separately the longitudinal and transverse optic branches, thus giving us the possibility of a second band-gap. Finally, we investigate the effect of the gradient inertia [Formula: see text] on more classical enriched models such as the Mindlin-Eringen and the internal variable ones. We find that the addition of such a gradient micro-inertia allows for the onset of one band-gap in the Mindlin-Eringen model and three band-gaps in the internal variable model. In this last case, however, non-local effects cannot be accounted for, which is a too drastic simplification for most metamaterials. We conclude that, even when adding gradient micro-inertia terms, the relaxed micromorphic model remains the best performing one, among the considered enriched models, for the description of non-local band-gap metamaterials.
Sleep inertia during a simulated 6-h on/6-h off fixed split duty schedule.
Hilditch, Cassie J; Short, Michelle; Van Dongen, Hans P A; Centofanti, Stephanie A; Dorrian, Jillian; Kohler, Mark; Banks, Siobhan
Sleep inertia is a safety concern for shift workers returning to work soon after waking up. Split duty schedules offer an alternative to longer shift periods, but introduce additional wake-ups and may therefore increase risk of sleep inertia. This study investigated sleep inertia across a split duty schedule. Sixteen participants (age range 21-36 years; 10 females) participated in a 9-day laboratory study with two baseline nights (10 h time in bed, [TIB]), four 24-h periods of a 6-h on/6-h off split duty schedule (5-h TIB in off period; 10-h TIB per 24 h) and two recovery nights. Two complementary rosters were evaluated, with the timing of sleep and wake alternating between the two rosters (2 am/2 pm wake-up roster versus 8 am/8 pm wake-up roster). At 2, 17, 32 and 47 min after scheduled awakening, participants completed an 8-min inertia test bout, which included a 3-min psychomotor vigilance test (PVT-B), a 3-min Digit-Symbol Substitution Task (DSST), the Karolinska Sleepiness Scale (KSS), and the Samn-Perelli Fatigue Scale (SP-Fatigue). Further testing occurred every 2 h during scheduled wakefulness. Performance was consistently degraded and subjective sleepiness/fatigue was consistently increased during the inertia testing period as compared to other testing times. Morning wake-ups (2 am and 8 am) were associated with higher levels of sleep inertia than later wake-ups (2 pm and 8 pm). These results suggest that split duty workers should recognise the potential for sleep inertia after waking, especially during the morning hours.
Lebeau, Jean-Pierre; Cadwallader, Jean-Sébastien; Aubin-Auger, Isabelle; Mercier, Alain; Pasquet, Thomas; Rusch, Emmanuel; Hendrickx, Kristin; Vermeire, Etienne
2014-07-02
Therapeutic inertia has been defined as the failure of health-care provider to initiate or intensify therapy when therapeutic goals are not reached. It is regarded as a major cause of uncontrolled hypertension. The exploration of its causes and the interventions to reduce it are plagued by unclear conceptualizations and hypothesized mechanisms. We therefore systematically searched the literature for definitions and discussions on the concept of therapeutic inertia in hypertension in primary care, to try and form an operational definition. A systematic review of all types of publications related to clinical inertia in hypertension was performed. Medline, EMbase, PsycInfo, the Cochrane library and databases, BDSP, CRD and NGC were searched from the start of their databases to June 2013. Articles were selected independently by two authors on the basis of their conceptual content, without other eligibility criteria or formal quality appraisal. Qualitative data were extracted independently by two teams of authors. Data were analyzed using a constant comparative qualitative method. The final selection included 89 articles. 112 codes were grouped in 4 categories: terms and definitions (semantics), "who" (physician, patient or system), "how and why" (mechanisms and reasons), and "appropriateness". Regarding each of these categories, a number of contradictory assertions were found, most of them relying on little or no empirical data. Overall, the limits of what should be considered as inertia were not clear. A number of authors insisted that what was considered deleterious inertia might in fact be appropriate care, depending on the situation. Our data analysis revealed a major lack of conceptualization of therapeutic inertia in hypertension and important discrepancies regarding its possible causes, mechanisms and outcomes. The concept should be split in two parts: appropriate inaction and inappropriate inertia. The development of consensual and operational definitions
Ritchie, Hannah K; Burke, Tina M; Dear, Tristan B; Mchill, Andrew W; Axelsson, John; Wright, Kenneth P
2017-10-01
Sleep inertia is affected by circadian phase, with worse performance upon awakening from sleep during the biological night than biological day. Visual search/selective visual attention performance is known to be sensitive to sleep inertia and circadian phase. Individual differences exist in the circadian timing of habitual wake time, which may contribute to individual differences in sleep inertia. Because later chronotypes awaken at an earlier circadian phase, we hypothesized that later chronotypes would have worse visual search performance during sleep inertia than earlier chronotypes if awakened at habitual wake time. We analysed performance from 18 healthy participants [five females (22.1 ± 3.7 years; mean ± SD)] at ~1, 10, 20, 30, 40 and 60 min following electroencephalogram-verified awakening from an 8 h in-laboratory sleep opportunity. Cognitive throughput and reaction times of correct responses were impaired by sleep inertia and took ~10-30 min to improve after awakening. Regardless whether chronotype was defined by dim light melatonin onset or mid-sleep clock hour on free days, derived from the Munich ChronoType Questionnaire, the duration of sleep inertia for cognitive throughput and reaction times was longer for later chronotypes (n = 7) compared with earlier chronotypes (n = 7). Specifically, performance for earlier chronotypes showed significant improvement within ~10-20 min after awakening, whereas performance for later chronotypes took ~30 min or longer to show significant improvement (P inertia contributes to longer-lasting impairments in morning performance in later chronotypes. © 2017 European Sleep Research Society.
Studies of the nuclear inertia in fission and heavy-ion reactions
International Nuclear Information System (INIS)
Moeller, P.; Nix, J.R.
1978-01-01
On the basis of the non-self-consistent cranking model the authors study some aspects of the nuclear inertia of interest in fission and heavy-ion reactions. First, the authors consider in the adiabatic limit the inertia for a doubly closed-shell nucleus in a deformed spheroidal harmonic-oscillator single-particle potential plus a small perturbation. When expressed in terms of a coordinate that describes the deformation of the nuclear matter distribution, the inertia for small oscillations about a spherical shape is exactly equal to the incompressible, irrotational value. For large distortions it deviates from the incompressible, irrotational value by up to about +-1% away from level crossings. Second, in order to study the dependence of the inertia upon a level crossing, two levels of the above system are considered. This is done both in the adiabatic limit and for large collective velocities. At level crossings the adiabatic inertia relative to the deformation of the matter distribution diverges as 1/modΔV, where modΔV is the magnitude of the perturbation. However, for large collective velocities the contribution to the inertia from a level crossing is less than 4modΔV(d(rsub(m))/dt) 2 where d(rsub(m))/dt is the collective velocity of the matter distribution. Although the effect of large velocities on the remaining levels of the many-body system or the effect of a statistical ensemble of states has not been considered, some of the results suggest that for high excitation energies and moderately large collective velocities the nuclear inertia approaches approximately the irrotational value. (Auth.)
Energy Technology Data Exchange (ETDEWEB)
Mirzadzhanzade, A Kh; Dedusanko, G Ya; Dinaburg, L S; Markov, Yu M; Rasizade, Ya N; Rozov, V N; Sherstnev, N M
1979-08-30
A drilling fluid is suggested for separating the drilling and plugging fluids which contains as the base increased solution of polyacrylamide and additive. In order to increase the viscoelastic properties of the liquid with simultaneous decrease in the periods of its fabrication, the solution contains as an additive dry bentonite clay. In cases of the use of a buffer fluid under conditions of negative temperatures, it is necessary to add to it table salt or ethylene glycol.
Inertia Wheel on Low-Noise Active Magnetic Suspension
Carabelli, S.; Genta, G.; Silvagni, M.; Tonoli, A.
2002-01-01
precision in force measuring or vibration isolation which are required. Note that the stiffness of a magnetic suspension usually increases when it must compensate for a large static force and the increase of stiffness changes drastically the vibration isolation characteristics. It is also possible to support the rotor using a separate controlled electromagnet, but the latter will introduce disturbances which make impossible to evaluate the performances of the magnetic levitation system. Moreover, the sensitivity of the device to the operating conditions makes testing in conditions so different from the actual ones of very little significance. This is particularly true when accurate force measuring or vibration isolation is required or when low power consumption is one of the design specifications. Finally, if an external electromagnetic device is used for compensating for weight, its presence changes the stiffness of the system, to the point of altering drastically its stability characteristics. Parabolic flight is not a solution for this problem: the duration of low gravity conditions during parabolic flights is too short to perform significant experiments on magnetic suspension systems, particularly if the natural frequency of the suspension is very low as is typical of devices aimed at the isolation from low frequency vibrations. The environment in which parabolic flight testing is performed is also too rough for accurate testing. The availability of the space station changes deeply this situation: magnetic levitation systems built for space application can be tested in conditions which are very close to the operating ones. Although the space station environment is not vibrationally so clean as it would be necessary for some application, it is nevertheless far better than any simulated environment on the ground. The present paper deals with the design and construction of an engineering model of an inertia wheel on AMB. The aim of the project is to test the performance of
The role of fluid viscosity in an immersed granular collapse
Yang, Geng Chao; Kwok, Chung Yee; Sobral, Yuri Dumaresq
2017-06-01
Instabilities of immersed slopes and cliffs can lead to catastrophic events that involve a sudden release of huge soil mass. The scaled deposit height and runout distance are found to follow simple power laws when a granular column collapses on a horizontal plane. However, if the granular column is submerged in a fluid, the mobility of the granular collapse due to high inertia effects will be reduced by fluid-particle interactions. In this study, the effects of fluid viscosity on granular collapse is investigated qualitatively by adopting a numerical approach based on the coupled lattice Boltzmann method (LBM) and discrete element method (DEM). It is found that the granular collapse can be dramatically slowed down due to the presence of viscous fluids. For the considered granular configuration, when the fluid viscosity increases. the runout distance decreases and the final deposition shows a larger deposit angle.
The role of fluid viscosity in an immersed granular collapse
Directory of Open Access Journals (Sweden)
Yang Geng Chao
2017-01-01
Full Text Available Instabilities of immersed slopes and cliffs can lead to catastrophic events that involve a sudden release of huge soil mass. The scaled deposit height and runout distance are found to follow simple power laws when a granular column collapses on a horizontal plane. However, if the granular column is submerged in a fluid, the mobility of the granular collapse due to high inertia effects will be reduced by fluid-particle interactions. In this study, the effects of fluid viscosity on granular collapse is investigated qualitatively by adopting a numerical approach based on the coupled lattice Boltzmann method (LBM and discrete element method (DEM. It is found that the granular collapse can be dramatically slowed down due to the presence of viscous fluids. For the considered granular configuration, when the fluid viscosity increases. the runout distance decreases and the final deposition shows a larger deposit angle.
Diagnostic inertia in dyslipidaemia: results of a preventative programme in Spain
Directory of Open Access Journals (Sweden)
Antonio Palazón-Bru
2015-07-01
Full Text Available Others have analysed the relationship between inadequate behaviour by healthcare professionals in the diagnosis of dyslipidaemia (diagnostic inertia and the history of cardiovascular risk factors. However, since no study has assessed cardiovascular risk scores as associated factors, we carried out a study to quantify diagnostic inertia in dyslipidaemia and to determine if cardiovascular risk scores are associated with this inertia. In the Valencian Community (Spain, a preventive programme (cardiovascular, gynaecologic and vaccination was started in 2003 inviting persons aged ≥40 years to undergo a health check-up at their health centre. This cross-sectional study examined persons with no known dyslipidaemia seen during the first six months of the programme (n = 16, 905 but whose total cholesterol (TC was ≥5.17 mmol/L. Diagnostic inertia was defined as lack of follow-up to confirm/discard the dyslipidaemia diagnosis. Other variables included in the analysis were gender, history of cardiovascular risk factors/cardiovascular disease, counselling (diet/exercise, body mass index (BMI, age, blood pressure, fasting blood glucose and lipids. TC was grouped as ≥/<6.20 mmol/L. In patients without cardiovascular disease and <75/≤65 years (n = 15, 778/13, 597, the REGICOR (REgistre GIroní del COr/SCORE (Systematic COronary Risk Evaluation cardiovascular risk functions were used to classify risk (high/low. Inertia was quantified and the adjusted odds ratios calculated from multivariate models. In the overall sample, the rate of diagnostic inertia was 52% (95% CI [51.2–52.7]; associated factors were TC ≥ 6.20 mmol/L, high or “not measured” BMI, hypertension, smoking and higher values of fasting blood glucose, systolic blood pressure and TC. In the REGICOR sample, the rate of diagnostic inertia was 51.9% (95% CI [51.1–52.7]; associated factors were REGICOR high and high or “not measured” BMI. In the SCORE sample the rate of diagnostic
The Bumper Boats Effect: Effect of Inertia on Self Propelled Active Particles Systems
Dai, Chengyu; Bruss, Isaac; Glotzer, Sharon
Active matter has been well studied using the standard Brownian dynamics model, which assumes that the self-propelled particles have no inertia. However, many examples of active systems, such as sub-millimeter bacteria and colloids, have non-negligible inertia. Using particle-based Langevin Dynamics simulation with HOOMD-blue, we study the role of particle inertia on the collective emergent behavior of self-propelled particles. We find that inertia hinders motility-induced phase separation. This is because the effective speed of particles is reduced due to particle-particle collisions-\\x9Dmuch like bumper boats, which take time to reach terminal velocity after a crash. We are able to fully account for this effect by tracking a particle's average rather than terminal velocity, allowing us to extend the standard Brownian dynamics model to account for the effects of momentum. This study aims to inform experimental systems where the inertia of the active particles is non-negligible. We acknowledge the funding support from the Center for Bio-Inspired Energy Science (CBES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0000989.
Under-treatment of type 2 diabetes: Causes and outcomes of clinical inertia.
Bailey, Clifford J
2016-12-01
To assess the impact of clinical inertia on type 2 diabetes (T2D) care. PubMed database search from January 2000 until December 2015. Clinical inertia, defined as resistance to initiate or intensify treatment in a patient not at the evidence-based glycated haemoglobin goal, is conservatively estimated to occur in at least 25% of patients with T2D. Consequently, many patients with diagnosed and treated T2D experience extended periods, in some cases years, of ineffectively controlled hyperglycaemia, potentially causing serious microvascular and macrovascular harm. Delayed treatment does not appear to be specific to primary care, but also occurs in the specialist setting. The causes of clinical inertia appear to be complex, involving both reasonable and unacceptable delays on the part of the clinician and poor compliance with treatment regimens on the part of the patient. Evidence suggests that the clinical and organisational context may be particularly important in reinforcing clinical inertia, notably the increasingly severe time constraints for diagnosis and management of multiple morbidities, consideration of complex guidelines, assessment of cost and appreciation of patient concerns, all of which may hamper prioritisation of the important issue of under-treatment. Since the pharmacotherapeutic tools for good control of blood glucose exist in all advanced healthcare systems, initiatives to address the important and widespread problem of clinical inertia may require focused campaigns that encourage attention to guideline recommendations and their adaptation for individualised care. © 2016 John Wiley & Sons Ltd.
International Nuclear Information System (INIS)
Lecocq, F.; Hourcade, J.-C.; Ha Duong, M.
1998-01-01
Current debates on climate mitigation emphasize the role of the inertia of the economic system. Our aim in this paper is to study in more depth how sectorally differentiated inertia impacts on optimal CO 2 -emission abatement policies. Using the STARTS model, we show that optimal abatement levels and costs differ sensibly among sectors. Differential inertia is the critical determinant of this trade-off, especially in the case of a 20-year delay in the action, or in an underestimation of the growth of the transportation sector. In particular, the burden of any additional abatement effort falls on the most flexible sector, i.e. the industry. Debates on mitigation emphasize the role of inertia of the economic system. This paper aims at studying more in depth how sectorally differentiated inertia should influence optimal CO 2 emission abatement policies. Using a two-sector version of STARTS, we show that under perfect expectations, optimal abatement profiles and associated costs differ sensibly between a flexible and a rigid sector (transportation). In a second step, we scrutinize the role of the uncertainty by testing the case of a 20-year delay of action and an underestimated growth of the transportation sector. We do this for three concentration ceilings and we point out the magnitude of the burden which falls on the flexible sector. We derive some policy implications for the ranking of public policies and for incentive instruments to be set up at international level. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)
Constraining the radius of neutron stars through the moment of inertia
International Nuclear Information System (INIS)
Greif, S.K.
2017-01-01
Neutron star observations provide systematic constraints on the nuclear equation of state like the recent discovery of 2 M neutron stars. While neutron star masses can be measured very precisely, their radii are inherently difficult to measure due to the influence from large systematic uncertainties. A promising alternative access to this information is the moment of inertia, which provides constraints for both radii and the equation of state. This will be possible in the future using pulsar timing observations. We present a theoretical framework for calculating moments of inertia microscopically. We use state-of-the-art equations of state that are based on chiral effective field theory interactions and fulfill the requirements of causality and of reproducing 2 M neutron stars. This allows us to generate a large set of equations of state that predict combinations of masses, radii, and moments of inertia. We investigate the impact of a moment of inertia measurement on the radius within this general setup. Based on our results, we show how future measurements of moments of inertia constrain radii of neutron stars and thus the equation of state. (author)
Two-dimensional plasma expansion in a magnetic nozzle: Separation due to electron inertia
International Nuclear Information System (INIS)
Ahedo, Eduardo; Merino, Mario
2012-01-01
A previous axisymmetric model of the supersonic expansion of a collisionless, hot plasma in a divergent magnetic nozzle is extended here in order to include electron-inertia effects. Up to dominant order on all components of the electron velocity, electron momentum equations still reduce to three conservation laws. Electron inertia leads to outward electron separation from the magnetic streamtubes. The progressive plasma filling of the adjacent vacuum region is consistent with electron-inertia being part of finite electron Larmor radius effects, which increase downstream and eventually demagnetize the plasma. Current ambipolarity is not fulfilled and ion separation can be either outwards or inwards of magnetic streamtubes, depending on their magnetization. Electron separation penalizes slightly the plume efficiency and is larger for plasma beams injected with large pressure gradients. An alternative nonzero electron-inertia model [E. Hooper, J. Propul. Power 9, 757 (1993)] based on cold plasmas and current ambipolarity, which predicts inwards electron separation, is discussed critically. A possible competition of the gyroviscous force with electron-inertia effects is commented briefly.
Waking up is the hardest thing I do all day: Sleep inertia and sleep drunkenness.
Trotti, Lynn M
2017-10-01
The transition from sleep to wake is marked by sleep inertia, a distinct state that is measurably different from wakefulness and manifests as performance impairments and sleepiness. Although the precise substrate of sleep inertia is unknown, electroencephalographic, evoked potential, and neuroimaging studies suggest the persistence of some features of sleep beyond the point of awakening. Forced desynchrony studies have demonstrated that sleep inertia impacts cognition differently than do homeostatic and circadian drives and that sleep inertia is most intense during awakenings from the biological night. Recovery sleep after sleep deprivation also amplifies sleep inertia, although the effects of deep sleep vary based on task and timing. In patients with hypersomnolence disorders, especially but not exclusively idiopathic hypersomnia, a more pronounced period of confusion and sleepiness upon awakening, known as "sleep drunkenness", is common and problematic. Optimal treatment of sleep drunkenness is unknown, although several medications have been used with benefit in small case series. Difficulty with awakening is also commonly endorsed by individuals with mood disorders, disproportionately to the general population. This may represent an important treatment target, but evidence-based treatment guidance is not yet available. Copyright © 2016 Elsevier Ltd. All rights reserved.
The moments of inertia of a rotational band 3/2- [521] isotones odd nuclei
International Nuclear Information System (INIS)
Karahodjaev, A.K.; Kuyjonov, H.
2003-01-01
The moments of inertia are received from experimental data from the following expression for energy of a level with spin I: E I = E 0 +ℎ 2 /2j·I(I+1), K≠l/2. The characteristics of low statuses of a rotational band 3/2 - [521] and inertial parameters 1.75A 1 keV ( A-1=ℎ 2 /2j) for nuclei 155 Dy and 155 Gd are given. The values of inertial parameters 1.75A1 keV for odd nuclei with N = 89, 91, 93, 95, 97, 99, 101 and 103 are presented. At quantity of neutrons N = 89 with increase of mass number of a nucleus the moment of inertia rather quickly grows. In nuclei with quantity of neutrons equal 91 and 93, with increase of mass number the moment of inertia of nuclei slowly changes and since A=159 and A=163, accordingly, begins sharply to grow. In isotones with N = 95, 97 and 99 moments of inertia decrease with increase of quantity neutrons in a nucleus. The reason of various dependence of the moment of inertia from mass number is, the coriolis interaction of an odd particle with even-even kernel and change of parameter of pair correlation because of presence of an odd particle above a kernel
Directory of Open Access Journals (Sweden)
Thongchart Kerdphol
2017-05-01
Full Text Available Renewable energy sources (RESs, such as wind and solar generations, equip inverters to connect to the microgrids. These inverters do not have any rotating mass, thus lowering the overall system inertia. This low system inertia issue could affect the microgrid stability and resiliency in the situation of uncertainties. Today’s microgrids will become unstable if the capacity of RESs become larger and larger, leading to the weakening of microgrid stability and resilience. This paper addresses a new concept of a microgrid control incorporating a virtual inertia system based on the model predictive control (MPC to emulate virtual inertia into the microgrid control loop, thus stabilizing microgrid frequency during high penetration of RESs. The additional controller of virtual inertia is applied to the microgrid, employing MPC with virtual inertia response. System modeling and simulations are carried out using MATLAB/Simulink® software. The simulation results confirm the superior robustness and frequency stabilization effect of the proposed MPC-based virtual inertia control in comparison to the fuzzy logic system and conventional virtual inertia control in a system with high integration of RESs. The proposed MPC-based virtual inertia control is able to improve the robustness and frequency stabilization of the microgrid effectively.
DEFF Research Database (Denmark)
Rezkalla, Michel M.N.; Zecchino, Antonio; Martinenas, Sergejus
2017-01-01
The increasing share of distributed and inertia-less resources entails an upsurge in balancing and system stabilisation services. In particular, the displacement of conventional generation reduces the available rotational inertia in the power system, leading to high interest in synthetic inertia....... The interdependency between frequency containment and synthetic inertia control on the transient frequency variation is shown analytically. The capabilities and limits of series produced EVs in providing such services are investigated, first on a simulation based approach and subsequently by using real hardware...
Karloff, Howard
1991-01-01
To this reviewer’s knowledge, this is the first book accessible to the upper division undergraduate or beginning graduate student that surveys linear programming from the Simplex Method…via the Ellipsoid algorithm to Karmarkar’s algorithm. Moreover, its point of view is algorithmic and thus it provides both a history and a case history of work in complexity theory. The presentation is admirable; Karloff's style is informal (even humorous at times) without sacrificing anything necessary for understanding. Diagrams (including horizontal brackets that group terms) aid in providing clarity. The end-of-chapter notes are helpful...Recommended highly for acquisition, since it is not only a textbook, but can also be used for independent reading and study. —Choice Reviews The reader will be well served by reading the monograph from cover to cover. The author succeeds in providing a concise, readable, understandable introduction to modern linear programming. —Mathematics of Computing This is a textbook intend...
Hydromagnetic thin film flow: Linear stability
Amaouche, Mustapha; Ait Abderrahmane, Hamid; Bourdache, Lamia
2013-01-01
. The linear stability of the problem is investigated, and the influence of electromagnetic field on the flow stability is analyzed. Two cases are considered: the applied magnetic field is either normal or parallel to the fluid flow direction, while
Directory of Open Access Journals (Sweden)
Matthias Hunstig
2017-02-01
Full Text Available Piezoelectric inertia motors—also known as stick-slip motors or (smooth impact drives—use the inertia of a body to drive it in small steps by means of an uninterrupted friction contact. In addition to the typical advantages of piezoelectric motors, they are especially suited for miniaturisation due to their simple structure and inherent fine-positioning capability. Originally developed for positioning in microscopy in the 1980s, they have nowadays also found application in mass-produced consumer goods. Recent research results are likely to enable more applications of piezoelectric inertia motors in the future. This contribution gives a critical overview of their historical development, functional principles, and related terminology. The most relevant aspects regarding their design—i.e., friction contact, solid state actuator, and electrical excitation—are discussed, including aspects of control and simulation. The article closes with an outlook on possible future developments and research perspectives.
Measurement of whole-body human centers of gravity and moments of inertia.
Albery, C B; Schultz, R B; Bjorn, V S
1998-06-01
With the inclusion of women in combat aircraft, the question of safe ejection seat operation has been raised. The potential expanded population of combat pilots would include both smaller and larger ejection seat occupants, which could significantly affect seat performance. The method developed to measure human whole-body CG and MOI used a scale, a knife edge balance, and an inverted torsional pendulum. Subjects' moments of inertia were measured along six different axes. The inertia tensor was calculated from these values, and principal moments of inertia were then derived. Thirty-eight antropometric measurements were also taken for each subject to provide a means for direct correlation of inertial properties to body dimensions and for modeling purposes. Data collected in this study has been used to validate whole-body mass properties predictions. In addition, data will be used to improve Air Force and Navy ejection seat trajectory models for the expanded population.
Newton's second law versus modified-inertia MOND: A test using the high-latitude effect
International Nuclear Information System (INIS)
Ignatiev, A. Yu.
2008-01-01
The modified-inertia MOND is an approach that proposes a change in Newton's second law at small accelerations as an alternative to dark matter. Recently it was suggested that this approach can be tested in terrestrial laboratory experiments. One way of doing the test is based on the static high-latitude equinox modified-inertia effect: around each equinox date, 2 spots emerge on the Earth where static bodies experience spontaneous displacement due to the violation of Newton's second law required by the modified-inertia MOND. Here, a detailed theory of this effect is developed and estimates of the magnitude of the signal due to the effect are obtained. The expected displacement of a mirror in a gravitational-wave interferometer is found to be about 10 -14 m. Some experimental aspects of the proposal are discussed
Directory of Open Access Journals (Sweden)
Klaus Kramer
2017-03-01
Full Text Available We propose a Cellular Automata (CA model in which three ubiquitous and relevant processes in nature are present, namely, spatial competition, distinction between dynamically stronger and weaker agents and the existence of an inner resistance to changes in the actual state S n (=−1,0,+1 of each CA lattice cell n (which we call inertia. Considering ensembles of initial lattices, we study the average properties of the CA final stationary configuration structures resulting from the system time evolution. Assuming the inertia a (proper control parameter, we identify qualitative changes in the CA spatial patterns resembling usual phase transitions. Interestingly, some of the observed features may be associated with continuous transitions (critical phenomena. However, certain quantities seem to present jumps, typical of discontinuous transitions. We argue that these apparent contradictory findings can be attributed to the inertia parameter’s discrete character. Along the work, we also briefly discuss a few potential applications for the present CA formulation.
Neutron-proton pairing effect on the proton-rich nuclei moment of inertia
International Nuclear Information System (INIS)
Mokhtari, D.; Ami, I.; Fellah, M.; Allal, N.H.; Fellah, M.; Allal, N.H.
2008-01-01
The neutron-proton (n-p) pairing effect on the nuclear moment of inertia is studied within the BCS approximation in the isovector case. An analytical expression of the moment of inertia is established by means of the cranking model. This expression generalizes the usual BCS one (i.e. when only the pairing between like-particles is considered). The moment of inertia of N = Z even-even nuclei, for which experimental values are known, i.e., such as 32 ≤ A ≤ 80, has been numerically evaluated, with and without inclusion of the n-p pairing effect. The used single-particle and Eigen-states are those of a deformed Woods-Saxon mean field. It turns out that the inclusion of the n-p pairing improves the obtained values when compared to the usual BCS approximation, since the average discrepancies with the experimental data are respectively 7% and 37%. (authors)
Neutron-proton pairing effect on the proton-rich nuclei moment of inertia
Energy Technology Data Exchange (ETDEWEB)
Mokhtari, D.; Ami, I.; Fellah, M.; Allal, N.H. [Laboratoire de Physique Theorique, Faculte de Physique, USTHB, Algiers (Algeria); Fellah, M.; Allal, N.H. [Centre de Recherche Nucleaire d' Alger, COMENA, Algiers (Algeria)
2008-07-01
The neutron-proton (n-p) pairing effect on the nuclear moment of inertia is studied within the BCS approximation in the isovector case. An analytical expression of the moment of inertia is established by means of the cranking model. This expression generalizes the usual BCS one (i.e. when only the pairing between like-particles is considered). The moment of inertia of N = Z even-even nuclei, for which experimental values are known, i.e., such as 32 {<=} A {<=} 80, has been numerically evaluated, with and without inclusion of the n-p pairing effect. The used single-particle and Eigen-states are those of a deformed Woods-Saxon mean field. It turns out that the inclusion of the n-p pairing improves the obtained values when compared to the usual BCS approximation, since the average discrepancies with the experimental data are respectively 7% and 37%. (authors)
Neutron-proton isovector pairing effect on the nuclear moment of inertia
International Nuclear Information System (INIS)
Mokhtari, D.; Ami, I.; Fellah, M.; Allal, N.H.
2008-01-01
The neutron-proton (n-p) isovector pairing effect on the nuclear moment of inertia has been studied within the framework of the BCS approximation. An analytical expression of the moment of inertia, that explicitly depends upon the n-p pairing, has been established using the Inglis cranking model. The model was first tested numerically for nuclei such as N = Z and whose experimental values of the moment of inertia are known (i.e. such as 16 ≤ Z ≤ 40). It has been shown that the n-p pairing effect is non-negligible and clearly improves the theoretical predictions when compared to those of the pairing between like particles. Secondly, predictions have been established for even-even proton-rich rare-earth nuclei. It has been shown that the n-p pairing effect is non-negligible when N = Z and rapidly decreases with increasing values of (N-Z). (author)
A Virtual Inertia Control Strategy for DC Microgrids Analogized with Virtual Synchronous Machines
DEFF Research Database (Denmark)
Wu, Wenhua; Chen, Yandong; Luo, An
2017-01-01
In a DC microgrid (DC-MG), the dc bus voltage is vulnerable to power fluctuation derived from the intermittent distributed energy or local loads variation. In this paper, a virtual inertia control strategy for DC-MG through bidirectional grid-connected converters (BGCs) analogized with virtual...... synchronous machine (VSM) is proposed to enhance the inertia of the DC-MG, and to restrain the dc bus voltage fluctuation. The small-signal model of the BGC system is established, and the small-signal transfer function between the dc bus voltage and the dc output current of the BGC is deduced. The dynamic...... for the BGC is introduced to smooth the dynamic response of the dc bus voltage. By analyzing the control system stability, the appropriate virtual inertia control parameters are selected. Finally, simulations and experiments verified the validity of the proposed control strategy....
Konovalov, P V; Mitrofanova, L B; Gorshkov, A N; Ovsyannikov, F A
2015-01-01
to reveal the morphological features of the lower uterine segment myometrium in connective tissue dysplasia (CTD) in women with uterine inertia. Histological, immunohistochemical (with antibodies against collagen types I and III, matrix metalloproteinases 1 and 9 (MMR-1, MMP-9), tissue inhibitor of metalloproteinase 1 (TIMP-1), fibronectin; fibulin-5, connexin-43), electron microscopic, and electron immunocytochemical studies with morphometry of myometrial fragments from 15 parturient women with CTD and uterine inertia (a study group) and those from 10 women without CTD (a control group). The myometrium in CTD exhibited the decreased expression of connextin-43, fibulin-5, TIMP-1, collagens types I and III with collagen type III predominance and the unchanged levels of fibronectin and MMP-1 and MMP-9. Electron microscopy and immunocytochemistry showed fewer intercellular contacts and the dramatically lower expression of connexin-43 than in the control. A set of found myometrial changes in women with uterine inertia is a manifestation of CTD.
An improved method in the measurement of the moment of inertia
Energy Technology Data Exchange (ETDEWEB)
Peng, Jun, E-mail: pengjun@cimm.com.cn [Key Laboratory for Metrology, Changcheng Institute of Metrology and Measurement (CIMM) Beijing (China); Zhang, Li, E-mail: zhangli@cimm.com.cn [Key Laboratory for Metrology, Changcheng Institute of Metrology and Measurement (CIMM) Beijing (China); School of Instrumentation Science and Opto-electronics Engineering, Beihang University, Beijing (China)
2016-06-28
The moment of inertia calibration system is developed by Changcheng Institute of Metrology and Measurement (CIMM). Rotation table - torsional spring system is used to generate angular vibration, and laser vibrometer is used to measure rotational angle and the vibration period. The object to be measured is mounted on the top of the rotation table. The air-bearing system is elaborately manufactured which reduce the friction of the angular movement and increase measurement accuracy. Heterodyne laser interferometer collaborates with column diffraction grating is used in the measurement of angular movement. Experiment shows the method of measuring oscillating angle and period introduced in this paper is stable and the time resolution is high. When the air damping effect can’t be neglected in moment of inertia measurement, the periodic waveform area ratio method is introduced to calculate damping ratio and obtain the moment of inertia.
Changing Provider Behavior in the Context of Chronic Disease Management: Focus on Clinical Inertia.
Lavoie, Kim L; Rash, Joshua A; Campbell, Tavis S
2017-01-06
Widespread acceptance of evidence-based medicine has led to the proliferation of clinical practice guidelines as the primary mode of communicating current best practices across a range of chronic diseases. Despite overwhelming evidence supporting the benefits of their use, there is a long history of poor uptake by providers. Nonadherence to clinical practice guidelines is referred to as clinical inertia and represents provider failure to initiate or intensify treatment despite a clear indication to do so. Here we review evidence for the ubiquity of clinical inertia across a variety of chronic health conditions, as well as the organizational and system, patient, and provider factors that serve to maintain it. Limitations are highlighted in the emerging literature examining interventions to reduce clinical inertia. An evidence-based framework to address these limitations is proposed that uses behavior change theory and advocates for shared decision making and enhanced guideline development and dissemination.
Egerton-Warburton, Diana; Cullen, Louise; Keijzers, Gerben; Fatovich, Daniel M
2018-06-01
Appropriate deliberate clinical inertia refers to the art of doing nothing as a positive clinical response. It includes shared decision-making to improve patient care with the use of clinical judgement. We discuss common clinical scenarios where the use of deliberate clinical inertia can occur. The insertion of peripheral intravenous cannulae, investigating patients with suspected renal colic and the investigation of low risk chest pain are all opportunities for the thoughtful clinician to 'stand there' and use effective patient communication to avoid low value tests and procedures. Awareness is key to identifying these opportunities to practice deliberate clinical inertia, as many of the situations may be so much a part of our environment that they are hidden in plain view. © 2018 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.
Atmospheric effects on the remote determination of thermal inertia on Mars
International Nuclear Information System (INIS)
Haberle, R.M.; Jakosky, B.M.
1991-01-01
Measurements of the IR brightness temperature at the Martian surface at many different times of day are presently compared with temperatures predicted by thermal models which allow sunlight to reach the surface unattenuated, in order to determine the thermal inertia of the uppermost 1-10 cm of the Martian surface. The consequences of the assumptions made are assessed in view of results from a different thermal model which invokes radiation-transfer through a dusty CO2 atmosphere, as well as sensible heat-exchange with the surface. Smaller thermal inertias imply smaller particle sizes; the results obtained suggest that low thermal-inertia regions consist of 5-micron, rather than 50-micron, particle sizes. 52 refs
Identification of general linear mechanical systems
Sirlin, S. W.; Longman, R. W.; Juang, J. N.
1983-01-01
Previous work in identification theory has been concerned with the general first order time derivative form. Linear mechanical systems, a large and important class, naturally have a second order form. This paper utilizes this additional structural information for the purpose of identification. A realization is obtained from input-output data, and then knowledge of the system input, output, and inertia matrices is used to determine a set of linear equations whereby we identify the remaining unknown system matrices. Necessary and sufficient conditions on the number, type and placement of sensors and actuators are given which guarantee identificability, and less stringent conditions are given which guarantee generic identifiability. Both a priori identifiability and a posteriori identifiability are considered, i.e., identifiability being insured prior to obtaining data, and identifiability being assured with a given data set.
Stereovision-based pose and inertia estimation of unknown and uncooperative space objects
Pesce, Vincenzo; Lavagna, Michèle; Bevilacqua, Riccardo
2017-01-01
Autonomous close proximity operations are an arduous and attractive problem in space mission design. In particular, the estimation of pose, motion and inertia properties of an uncooperative object is a challenging task because of the lack of available a priori information. This paper develops a novel method to estimate the relative position, velocity, angular velocity, attitude and the ratios of the components of the inertia matrix of an uncooperative space object using only stereo-vision measurements. The classical Extended Kalman Filter (EKF) and an Iterated Extended Kalman Filter (IEKF) are used and compared for the estimation procedure. In addition, in order to compute the inertia properties, the ratios of the inertia components are added to the state and a pseudo-measurement equation is considered in the observation model. The relative simplicity of the proposed algorithm could be suitable for an online implementation for real applications. The developed algorithm is validated by numerical simulations in MATLAB using different initial conditions and uncertainty levels. The goal of the simulations is to verify the accuracy and robustness of the proposed estimation algorithm. The obtained results show satisfactory convergence of estimation errors for all the considered quantities. The obtained results, in several simulations, shows some improvements with respect to similar works, which deal with the same problem, present in literature. In addition, a video processing procedure is presented to reconstruct the geometrical properties of a body using cameras. This inertia reconstruction algorithm has been experimentally validated at the ADAMUS (ADvanced Autonomous MUltiple Spacecraft) Lab at the University of Florida. In the future, this different method could be integrated to the inertia ratios estimator to have a complete tool for mass properties recognition.
Reach, G; Pechtner, V; Gentilella, R; Corcos, A; Ceriello, A
2017-12-01
Many people with type 2 diabetes mellitus (T2DM) fail to achieve glycaemic control promptly after diagnosis and do not receive timely treatment intensification. This may be in part due to 'clinical inertia', defined as the failure of healthcare providers to initiate or intensify therapy when indicated. Physician-, patient- and healthcare-system-related factors all contribute to clinical inertia. However, decisions that appear to be clinical inertia may, in fact, be only 'apparent' clinical inertia and may reflect good clinical practice on behalf of the physician for a specific patient. Delay in treatment intensification can happen at all stages of treatment for people with T2DM, including prescription of lifestyle changes after diagnosis, introduction of pharmacological therapy, use of combination therapy where needed and initiation of insulin. Clinical inertia may contribute to people with T2DM living with suboptimal glycaemic control for many years, with dramatic consequences for the patient in terms of quality of life, morbidity and mortality, and for public health because of the huge costs associated with uncontrolled T2DM. Because multiple factors can lead to clinical inertia, potential solutions most likely require a combination of approaches involving fundamental changes in medical care. These could include the adoption of a person-centred model of care to account for the complex considerations influencing treatment decisions by patients and physicians. Better patient education about the progressive nature of T2DM and the risks inherent in long-term poor glycaemic control may also reinforce the need for regular treatment reviews, with intensification when required. Copyright © 2017 The Authors. Published by Elsevier Masson SAS.. All rights reserved.
Khunti, Kamlesh; Gomes, Marilia B; Pocock, Stuart; Shestakova, Marina V; Pintat, Stéphane; Fenici, Peter; Hammar, Niklas; Medina, Jesús
2018-02-01
Therapeutic inertia, defined as the failure to initiate or intensify therapy in a timely manner according to evidence-based clinical guidelines, is a key reason for uncontrolled hyperglycaemia in patients with type 2 diabetes. The aims of this systematic review were to identify how therapeutic inertia in the management of hyperglycaemia was measured and to assess its extent over the past decade. Systematic searches for articles published from January 1, 2004 to August 1, 2016 were conducted in MEDLINE and Embase. Two researchers independently screened all of the titles and abstracts, and the full texts of publications deemed relevant. Data were extracted by a single researcher using a standardized data extraction form. The final selection for the review included 53 articles. Measurements used to assess therapeutic inertia varied across studies, making comparisons difficult. Data from low- to middle-income countries were scarce. In most studies, the median time to treatment intensification after a glycated haemoglobin (HbA1c) measurement above target was more than 1 year (range 0.3 to >7.2 years). Therapeutic inertia increased as the number of antidiabetic drugs rose and decreased with increasing HbA1c levels. Data were mainly available from Western countries. Diversity of inertia measures precluded meta-analysis. Therapeutic inertia in the management of hyperglycaemia in patients with type 2 diabetes is a major concern. This is well documented in Western countries, but corresponding data are urgently needed in low- and middle-income countries, in view of their high prevalence of type 2 diabetes. © 2017 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.
Hilditch, Cassie J; Dorrian, Jillian; Banks, Siobhan
2017-04-01
Napping is a widely used countermeasure to sleepiness and impaired performance caused by sleep loss and circadian pressure. Sleep inertia, the period of grogginess and impaired performance experienced after waking, is a potential side effect of napping. Many industry publications recommend naps of 30 min or less to avoid this side effect. However, the evidence to support this advice is yet to be thoroughly reviewed. Electronic databases were searched, and defined criteria were applied to select articles for review. The review covers literature on naps of 30 min or less regarding (a) sleep inertia, (b) slow-wave sleep (SWS) and (c) the relationship between sleep inertia and SWS. The review found that although the literature on short afternoon naps is relatively comprehensive, there are very few studies on naps of 30 min or less at night. Studies have mixed results regarding the onset of SWS and the duration and severity of sleep inertia following short naps, making guidelines regarding their use unclear. The varying results are likely due to differing sleep/wake profiles before the nap of interest and the time of the day at waking. The review highlights the need to have more detailed guidelines about the implementation of short naps according to the time of the day and prior sleep/wake history. Without this context, such a recommendation is potentially misleading. Further research is required to better understand the interactions between these factors, especially at night, and to provide more specific recommendations. Copyright © 2017 Elsevier B.V. All rights reserved.
Kubiak, Marta; Mège, Daniel; Gurgurewicz, Joanna; Ciazela, Jakub
2015-04-01
Thermal inertia (P) is an important property of geologic surfaces that essentially describes the resistance to temperature (T) change as heat is added. Most remote sensing data describe the surface only. P is a volume property that is sensitive to the composition of the subsurface, down to a depth reached by the diurnal heating wave. As direct measurement of P is not possible on Mars, thermal inertia models (Fergason et al., 2006) and deductive methods (the Apparent Thermal Inertia: ATI and Differential Apparent Thermal Inertia: DATI) are used to estimate it. ATI is computed as (1 - A) / (Tday - Tnight), where A is albedo. Due to the lack of the thermal daytime images with maximum land surface temperature (LST) and nighttime images with minimum LST in Valles Marineris region, the ATI method is difficult to apply. Instead, we have explored the DATI technique (Sabol et al., 2006). DATI is calculated based on shorter time (t) intervals with a high |ΔT/Δt| gradient (in the morning or in the afternoon) and is proportional to the day/night temperature difference (ATI), and hence P. Mars, which exhibits exceptionally high |ΔT/Δt| gradients due to the lack of vegetation and thin atmosphere, is especially suitable for the DATI approach. Here we present a new deductive method for high-resolution differential apparent thermal inertia (DATI) mapping for areas of highly contrasted relief (e.g., Valles Marineris). Contrary to the thermal inertia models, our method takes local relief characteristics (slopes and aspects) into account. This is crucial as topography highly influences A and ΔT measurements. In spite of the different approach, DATI values in the flat areas are in the same range as the values obtained by Fergason et al. (2006). They provide, however, more accurate information for geological interpretations of hilly or mountainous terrains. Sabol, D. E., Gillespie, A. R., McDonald, E., and Danilina, I., 2006. Differential Thermal Inertia of Geological Surfaces. In
Importance of Upper-Limb Inertia in Calculating Concentric Bench Press Force
RAMBAUD, O; RAHMANI, A; MOYEN, B; BOURDIN, M
2008-01-01
The purpose of this study was to investigate the influence of upper-limb inertia on the force-velocity relationship and maximal power during concentric bench press exercise. Reference peak force values (Fpeakp) measured with a force plate positioned below the bench were compared to those measured simultaneously with a kinematic device fixed on the barbell by taking (Fpeakt) or not taking (Fpeakb) upper-limb inertia into account. Thirteen men (27.8 6 4.1 years, 184.6 6 5.5 cm, 99.5 6 18.6 kg) ...
Experimental study of the conventional equation to determine a plate's moment of inertia
International Nuclear Information System (INIS)
Pintao, Carlos A F; Filho, Moacir P de Souza; Grandini, Carlos R; Hessel, Roberto
2004-01-01
In this work, we describe an experimental setup in which an electric current is used to determine the angular velocity attained by a plate rotating around a shaft in response to a torque applied for a given period. Based on this information, we show how the moment of inertia of a plate can be determined using a procedure that differs considerably from the ones most commonly used, which generally involve time measurements. Some experimental results are also presented which allow one to determine parameters such as the exponents and constant of the conventional equation of a plate's moment of inertia
Material inertia and size effects in the Charpy V-notch test
DEFF Research Database (Denmark)
Desandre, D. A.; Benzerga, A. A.; Tvergaard, Viggo
2004-01-01
The effect of material inertia on the size dependence of the absorbed energy in the Charpy V-notch test is investigated. The material response is characterized by an elastic-viscoplastic constitutive relation for a porous plastic solid, with adiabatic heating due to plastic dissipation and the re......The effect of material inertia on the size dependence of the absorbed energy in the Charpy V-notch test is investigated. The material response is characterized by an elastic-viscoplastic constitutive relation for a porous plastic solid, with adiabatic heating due to plastic dissipation...
Inducverters: PLL-Less Converters with Auto-Synchronization and Emulated Inertia Capability
DEFF Research Database (Denmark)
Ashabani, Mahdi; Freijedo Fernandez, Francisco Daniel; Golestan, Saeed
2016-01-01
current information and can track grid frequency, angle and voltage amplitude variations while feeding constant amount of power which is of high interest in frequency varying grids and also in the case of grid voltage angle jump. Another advantage of the inducverter is that it introduces virtual inertia...... impedance. The controller also offers stable and high-performance synchronization and operation under unbalanced and/or distorted grid conditions. The work beside synchronous current converters give a bird’s eye view to research in the new area of PLL-less and virtual inertia-based operation of VSCs...
Frequency participation by using virtual inertia in wind turbines including energy storage
DEFF Research Database (Denmark)
Xiao, Zhao xia; Huang, Yu; Guerrero, Josep M.
2017-01-01
With the increase of wind generation penetration, power fluctuations and weak inertia may attempt to the power system frequency stability. In this paper, in order to solve this problem, a hierarchical control strategy is proposed for permanent magnet synchronous generator (PMSG) based wind turbine...... (WT) and battery unit (BU). A central controller forecasts wind speed and determines system operation states to be sent to the local controllers. These local controllers include MPPT, virtual inertia, and pitch control for the WT; and power control loops for the BU. The proposed approach achieve...
Effective moments of inertia and spin cut off parameters in Hf isotopes
International Nuclear Information System (INIS)
Razavi, R.; Sharifzadeh, N.; Farahmand, M.R.
2011-01-01
In all statistical theories the nuclear level density is the most characteristic quantity and plays a major role in the study of nuclear structure. Most experimental data on nuclear level density have been analyzed with analytical functions of the level density. On the basis of statistical models, the effective moments of inertia and spin cut off parameters have been determined for 176 Hf, 178 Hf and 180 Hf nuclei from extensive and complete level schemes and neutron resonance densities in low excitation energy levels. Then, moments of inertia of these nuclei have been determined by nuclear rotational model. The results have been compared with their corresponding rigid body value
Energy Technology Data Exchange (ETDEWEB)
Navarro, J A; Madariaga, J A; Santamaria, C M; Saviron, J M
1980-07-01
10 refs. Flow pattern calculations in natural convection between two vertical coaxial cylinders are reported. It is assumed trough the paper. that fluid properties, viscosity, thermal conductivity and density, depend no-linearly on temperature and that the aspects (height/radius) ratio of the cylinders is high. Velocity profiles are calculated trough a perturbative scheme and analytic results for the three first perturbation orders are presented. We outline also an iterative method to estimate the perturbations on the flow patterns which arise when a radial composition gradient is established by external forces in a two-component fluid. This procedure, based on semiempirical basis, is applied to gaseous convection. The influence of the molecules gas properties on tho flow is also discussed. (Author) 10 refs.
International Nuclear Information System (INIS)
Nikonov, S.; Velkov, K.
2008-01-01
The ATHLET-BIPR-VVER coupled system code is applied for performing of safety analysis for different WWER reactors. During the last years its validation matrix is continuously being enlarged. The measurements performed during the commissioning phase of NPP Kalinin Unit 3 for the transient 'Switching-off of one Main Circulation Pump at nominal power' are very well documented and have a variety of recorded integral and local thermo-hydraulic and neutron-physic parameters including the measurements' errors. This data is being used for further validation of the coupled code system ATHLET-BIPR-VVER. In the paper are discussed the problems and our solutions by the correct interpretation of the measured thermocouples' records at NPP Kalinin-3 and the comparison with the predicted results by the coupled thermal-hydraulic/neutron-kinetic code ATHLET-BIPR-VVER. Of primary importance by such comparisons is the correct accounting of the fluid mixing process that take place in the surrounding of the measuring sensors and also the consideration of the time delay (inertia term) of the measuring devices. On the bases of previous experience and many simulations of the defined transient a method is discussed and proposed to consider correctly the inertia term of the thermocouples' measurements. The new modelling is implemented in the coupled system code ATHLET-BIPR-VVER for further validation. (Author)
Bernard, Peter S
2015-01-01
This book presents a focused, readable account of the principal physical and mathematical ideas at the heart of fluid dynamics. Graduate students in engineering, applied math, and physics who are taking their first graduate course in fluids will find this book invaluable in providing the background in physics and mathematics necessary to pursue advanced study. The book includes a detailed derivation of the Navier-Stokes and energy equations, followed by many examples of their use in studying the dynamics of fluid flows. Modern tensor analysis is used to simplify the mathematical derivations, thus allowing a clearer view of the physics. Peter Bernard also covers the motivation behind many fundamental concepts such as Bernoulli's equation and the stream function. Many exercises are designed with a view toward using MATLAB or its equivalent to simplify and extend the analysis of fluid motion including developing flow simulations based on techniques described in the book.
Reduction of Linear Programming to Linear Approximation
Vaserstein, Leonid N.
2006-01-01
It is well known that every Chebyshev linear approximation problem can be reduced to a linear program. In this paper we show that conversely every linear program can be reduced to a Chebyshev linear approximation problem.
Soloviev, A.; Dean, C.
2017-12-01
The artificial upwelling system consisting of the wave-inertia pumps driven by surface waves can produce flow of cold deep water to the surface. One of the recently proposed potential applications of the artificial upwelling system is the hurricane intensity mitigation. Even relatively small reduction of intensity may provide significant benefits. The ocean heat content (OHC) is the "fuel" for hurricanes. The OHC can be reduced by mixing of the surface layer with the cold water produced by wave-inertia pumps. Implementation of this system for hurricane mitigation has several oceanographic and air-sea interaction aspects. The cold water brought to the surface from a deeper layer has higher density than the surface water and, therefore, tends to sink back down. The mixing of the cold water produced by artificial upwelling depends on environmental conditions such as stratification, regional ocean circulation, and vertical shear. Another aspect is that as the sea surface temperature drops below the air temperature, the stable stratification develops in the atmospheric boundary layer. The stable atmospheric stratification suppresses sensible and latent heat air-sea fluxes and reduces the net longwave irradiance from the sea surface. As a result, the artificial upwelling may start increasing the OHC (though still reducing the sea surface temperature). In this work, the fate of the cold water in the stratified environment with vertical shear has been studied using computational fluid dynamics (CFD) tools. A 3D large eddy simulation model is initialized with observational temperature, salinity, and current velocity data from a sample location in the Straits of Florida. A periodic boundary condition is set along the direction of the current, which allows us to simulate infinite fetch. The model results indicate that the cold water brought to the sea surface by a wave-inertia pump forms a convective jet. This jet plunges into the upper ocean mixed layer and penetrates the
Directory of Open Access Journals (Sweden)
Isabelle Rogowski
Full Text Available This study examined the effect of the polar moment of inertia of a tennis racket on upper limb loading in the serve. Eight amateur competition tennis players performed two sets of 10 serves using two rackets identical in mass, position of center of mass and moments of inertia other than the polar moment of inertia (0.00152 vs 0.00197 kg.m2. An eight-camera motion analysis system collected the 3D trajectories of 16 markers, located on the thorax, upper limbs and racket, from which shoulder, elbow and wrist net joint moments and powers were computed using inverse dynamics. During the cocking phase, increased racket polar moment of inertia was associated with significant increases in the peak shoulder extension and abduction moments, as well the peak elbow extension, valgus and supination moments. During the forward swing phase, peak wrist extension and radial deviation moments significantly increased with polar moment of inertia. During the follow-through phase, the peak shoulder adduction, elbow pronation and wrist external rotation moments displayed a significant inverse relationship with polar moment of inertia. During the forward swing, the magnitudes of negative joint power at the elbow and wrist were significantly larger when players served using the racket with a higher polar moment of inertia. Although a larger polar of inertia allows players to better tolerate off-center impacts, it also appears to place additional loads on the upper extremity when serving and may therefore increase injury risk in tennis players.
Rogowski, Isabelle; Creveaux, Thomas; Chèze, Laurence; Macé, Pierre; Dumas, Raphaël
2014-01-01
This study examined the effect of the polar moment of inertia of a tennis racket on upper limb loading in the serve. Eight amateur competition tennis players performed two sets of 10 serves using two rackets identical in mass, position of center of mass and moments of inertia other than the polar moment of inertia (0.00152 vs 0.00197 kg.m2). An eight-camera motion analysis system collected the 3D trajectories of 16 markers, located on the thorax, upper limbs and racket, from which shoulder, elbow and wrist net joint moments and powers were computed using inverse dynamics. During the cocking phase, increased racket polar moment of inertia was associated with significant increases in the peak shoulder extension and abduction moments, as well the peak elbow extension, valgus and supination moments. During the forward swing phase, peak wrist extension and radial deviation moments significantly increased with polar moment of inertia. During the follow-through phase, the peak shoulder adduction, elbow pronation and wrist external rotation moments displayed a significant inverse relationship with polar moment of inertia. During the forward swing, the magnitudes of negative joint power at the elbow and wrist were significantly larger when players served using the racket with a higher polar moment of inertia. Although a larger polar of inertia allows players to better tolerate off-center impacts, it also appears to place additional loads on the upper extremity when serving and may therefore increase injury risk in tennis players.
Directory of Open Access Journals (Sweden)
Ming Yang
2018-03-01
Full Text Available In this paper, an on-line parameter identification algorithm to iteratively compute the numerical values of inertia and load torque is proposed. Since inertia and load torque are strongly coupled variables due to the degenerate-rank problem, it is hard to estimate relatively accurate values for them in the cases such as when load torque variation presents or one cannot obtain a relatively accurate priori knowledge of inertia. This paper eliminates this problem and realizes ideal online inertia identification regardless of load condition and initial error. The algorithm in this paper integrates a full-order Kalman Observer and Recursive Least Squares, and introduces adaptive controllers to enhance the robustness. It has a better performance when iteratively computing load torque and moment of inertia. Theoretical sensitivity analysis of the proposed algorithm is conducted. Compared to traditional methods, the validity of the proposed algorithm is proved by simulation and experiment results.
International Nuclear Information System (INIS)
Helled, R.
2011-01-01
Knowledge of Saturn's axial moment of inertia can provide valuable information on its internal structure. We suggest that Saturn's angular momentum may be determined by the Solstice Mission (Cassini XXM) by measuring Saturn's pole precession rate and the Lense-Thirring acceleration on the spacecraft, and therefore put constraints on Saturn's moment of inertia. It is shown that Saturn's moment of inertia can change up to ∼2% due to different core properties. However, a determination of Saturn's rotation rate is required to constrain its axial moment of inertia. A change of about seven minutes in rotation period leads to a similar uncertainty in the moment of inertia value as different core properties (mass, radius). A determination of Saturn's angular momentum and rotation period by the Solstice Mission could reveal important information on Saturn's internal structure, in particular, its core properties.
Lunar Fluid Core and Solid-Body Tides
Williams, J. G.; Boggs, D. H.; Ratcliff, J. T.
2005-01-01
Variations in rotation and orientation of the Moon are sensitive to solid-body tidal dissipation, dissipation due to relative motion at the fluid-core/solid-mantle boundary, and tidal Love number k2 [1,2]. There is weaker sensitivity to flattening of the core-mantle boundary (CMB) [2-5] and fluid core moment of inertia [1]. Accurate Lunar Laser Ranging (LLR) measurements of the distance from observatories on the Earth to four retroreflector arrays on the Moon are sensitive to lunar rotation and orientation variations and tidal displacements. Past solutions using the LLR data have given results for dissipation due to solid-body tides and fluid core [1] plus Love number [1-5]. Detection of CMB flattening has been improving [3,5] and now seems significant. This strengthens the case for a fluid lunar core.
Linear determining equations for differential constraints
International Nuclear Information System (INIS)
Kaptsov, O V
1998-01-01
A construction of differential constraints compatible with partial differential equations is considered. Certain linear determining equations with parameters are used to find such differential constraints. They generalize the classical determining equations used in the search for admissible Lie operators. As applications of this approach equations of an ideal incompressible fluid and non-linear heat equations are discussed
Sensorless interior permanent magnet synchronous motor control with rotational inertia adjustment
Directory of Open Access Journals (Sweden)
Yongle Mao
2016-12-01
Full Text Available Mechanical model is generally required in high dynamic sensorless motor control schemes for zero phase lag estimation of rotor position and speed. However, the rotational inertia uncertainty will cause dynamic estimation errors, eventually resulting in performance deterioration of the sensorless control system. Therefore, this article proposes a high dynamic performance sensorless control strategy with online adjustment of the rotational inertia. Based on a synthetic back electromotive force model, the voltage equation of interior permanent magnet synchronous motor is transformed to that of an equivalent non-salient permanent magnet synchronous motor. Then, an extended nonlinear observer is designed for interior permanent magnet synchronous motor in the stator-fixed coordinate frame, with rotor position, speed and load torque simultaneously estimated. The effect of inaccurate rotational inertia on the estimation of rotor position and speed is investigated, and a novel rotational inertia adjustment approach that employs the gradient descent algorithm is proposed to suppress the dynamic estimation errors. The effectiveness of the proposed control strategy is demonstrated by experimental tests.
Superfluid quenching of the moment of inertia in a strongly interacting Fermi gas
Riedl, S.; Sánchez Guajardo, E. R.; Kohstall, C.; Hecker Denschlag, J.; Grimm, R.
2011-03-01
We report on the observation of a quenched moment of inertia resulting from superfluidity in a strongly interacting Fermi gas. Our method is based on setting the hydrodynamic gas in slow rotation and determining its angular momentum by detecting the precession of a radial quadrupole excitation. The measurements distinguish between the superfluid and collisional origins of hydrodynamic behavior, and show the phase transition.
Christoffel symbols and inertia in flat space-time theory. [Curvilinear coordinate systems
Energy Technology Data Exchange (ETDEWEB)
Krause, J [Universidad Central de Venezuela, Caracas
1976-11-01
A necessary and sufficient criterion of inertia is presented, for the flat space-time theory of general frames of reference, in terms of the vanishing of some typical components of the affine connection pertaining to curvilinear coordinate systems. The physical identification of inertial forces thus arises in the context of the special theory of relativity.
Constraints on the Moment of Inertia of a Proto Neutron Star from the ...
Indian Academy of Sciences (India)
0} system. It is found that for a proto neu- tron star, the mass, the moment of inertia and their own maximum values as a function of .... Our previous work shows that such hyperon coupling constants can give the neutron star matter a better ...
Moment inertia pump analysis used in the Rsg-Gas primary coolant loop under lofa condition
International Nuclear Information System (INIS)
Sudarmono; Setiyanto; Dhandhang, P.; Dibyo, S.; Royadi
1998-01-01
The moment inertia of primary cooling system analysis under LOFA condition has been done. It is potentially one of limiting design constraints of the RSG-GAS safety because the coolant flow rate reduces very rapidly under LOFA condition due to the low inertia circulation pumps. If a loss of flow accident occurs, the mass flow will decrease rapidly and the heat transfer coefficient between cladding and coolant will also decreases. As a consequence the fuel and cladding temperature will increase. The whole core was represented by the 1/4 sector and divided into 19 subchannels and 40 axial nodes. In the present study, moment inertia of pump analysis for RSG-GAS reactor was performed with COBRA-IV-I subchannel code. As the DNB correlation, W-3 Correlation was selected for base case. The flow and power transients under pump trip accident were determined from experiments. The result above compared with the design data are 75 kg m 2 and 81 Kg m 2 respectively. The result shows that the RSG-GAS requires the inertia more than 75 kg m 2
Debats, N.B.; Kingma, I.; Beek, P.J.; Smeets, J.B.J.
2012-01-01
How does the magnitude of the exploration force influence the precision of haptic perceptual estimates? To address this question, we examined the perceptual precision for moment of inertia (i.e., an object's "angular mass") under different force conditions, using the Weber fraction to quantify
Crustal moment of inertia of glitching pulsars with the KDE0v1 Skyrme interaction
Energy Technology Data Exchange (ETDEWEB)
Madhuri, K.; Routray, T.R.; Pattnaik, S.P. [Sambalpur University, School of Physics, Jyotivihar (India); Basu, D.N. [Variable Energy Cyclotron Center, Kolkata (India)
2017-07-15
The mass, radius and crustal fraction of moment of inertia in neutron stars are calculated using β-equilibrated nuclear matter obtained from the Skyrme effective interaction. The transition density, pressure and proton fraction at the inner edge separating the liquid core from the solid crust of the neutron stars are determined from the thermodynamic stability conditions using the KDE0v1 set. The neutron star masses obtained by solving the Tolman-Oppenheimer-Volkoff equations using neutron star matter obtained from this set are able to describe highly massive compact stars ∝ 2M {sub CircleDot}. The crustal fraction of the moment of inertia can be extracted from studying pulsar glitches. This fraction is highly dependent on the core-crust transition pressure and corresponding density. These results for pressure and density at core-crust transition together with the observed minimum crustal fraction of the total moment of inertia provide a limit for the radius of the Vela pulsar, R ≥ 3.69 + 3.44M/M {sub CircleDot}. Present calculations suggest that the crustal fraction of the total moment of inertia can be ∝ 6.3% due to crustal entrainment caused by the Bragg reflection of unbound neutrons by lattice ions. (orig.)
On the origin of the inertia: The modified Newtonian dynamics theory
International Nuclear Information System (INIS)
Gine, Jaume
2009-01-01
It is shown that the identity between inertial mass and gravitational mass is an assumption to establish the equivalence principle. In the context of Sciama's inertia theory, the identity between the inertial mass and the gravitational mass is discussed and a certain condition which must be experimentally satisfied is given. The inertial force proposed by Sciama, in a simple case, is derived from Assis' inertia theory based in the introduction of a Weber type force. The origin of the inertial force is totally justified taking into account that the Weber force is, in fact, an approximation of a simple retarded potential, see [Gine J. On the origin of the anomalous precession of Mercury's perihelion. . Gine J. On the origin of deflection of the light. Chaos, Solitons and Fractals 2008;35(1):1-6]. The way how the inertial forces are also derived from some solutions of the general relativistic equations is presented. We wonder whether the theory of inertia of Assis is included in the framework the General Relativity. In the context of the inertia developed in the present paper, we establish the relation between the constant acceleration a 0 , that appears in the classical modified Newtonian dynamics (MOND) theory, with the Hubble constant H 0 , i.e. a 0 ∼ cH 0 .
Thermal Inertia of near-Earth Asteroids and Strength of the Yarkovsky Effect
Delbo, Marco; Dell'Oro, A.; Harris, A. W.; Mottola, S.; Mueller, M.
2006-01-01
Thermal inertia is the physical parameter that controls the temperature distribution over the surface of an asteroid. It affects the strength of the Yarkovsky effect, which causes orbital drift of km-sized asteroids and is invoked to explain the delivery of near-Earth asteroids (NEAs) from the main
MPC for Wind Power Gradients - Utilizing Forecasts, Rotor Inertia, and Central Energy Storage
DEFF Research Database (Denmark)
Hovgaard, Tobias Gybel; Larsen, Lars F. S.; Jørgensen, John Bagterp
2013-01-01
decentralized energy storage in the turbines’ inertia combined with a central storage unit or deferrable consumers can be utilized to achieve this goal at a minimum cost. We propose a variation on model predictive control to incorporate predictions of wind speed. Due to the aerodynamics of the turbines...
Richardson, Tim H.; Brittle, Stuart A.
2012-01-01
This paper describes a set of experiments aimed at overcoming some of the difficulties experienced by students learning about the topics of moments of inertia and simple harmonic motion, both of which are often perceived to be complex topics amongst students during their first-year university courses. By combining both subjects in a discussion…
Comparison of Various Dynamic Balancing Principles Regarding Additional Mass and Additional Inertia
van der Wijk, V.; Demeulenaere, Bram; Herder, Justus Laurens
2009-01-01
The major disadvantage of existing dynamic balancing principles is that a considerable amount of mass and inertia is added to the system. The objectives of this article are to summarize, to compare, and to evaluate existing complete balancing principles regarding the addition of mass and the
The Pole Orientation, Pole Precession, and Moment of Inertia Factor of Saturn
Jacobson, R. A.; French, R. G.; Nicholson, P. D.; Hedman, M.; Colwell, J. E.; Marouf, E.; Rappaport, N.; McGhee, C.; Sepersky, T.; Lonergan, K.
2011-01-01
This paper discusses our determination of the Saturn's pole orientation and precession using a combination of Earthbased and spacecraft based observational data. From our model of the polar motion and the observed precession rate we obtain a value for Saturn's polar moment of inertia
A generic inertia emulation controller for multi-terminal VSC-HVDC systems
DEFF Research Database (Denmark)
Zhu, Jiebei; Guerrero, Josep M.; Booth, Campbell
2013-01-01
A generic Inertia Emulation Controller (INEC) for Multi-Terminal Voltage-source-converter based HVDC (VSC-MTDC) is proposed in this paper. The proposed INEC can be incorporated in any grid-side-voltage-source-converter (GVSC) station, allowing the MTDC terminal to contribute an inertial response...
Modeling and Experimental Validation of an Islanded No-Inertia Microgrid Site
DEFF Research Database (Denmark)
Bonfiglio, Andrea; Delfino, Federico; Labella, Alessandro
2018-01-01
The paper proposes a simple but effective model for no-inertia microgrids suitable to represent the instantaneous values of its meaningful electric variables, becoming a useful platform to test innovative control logics and energy management systems. The proposed model is validated against a more...
Self-similarity of solitary waves on inertia-dominated falling liquid films.
Denner, Fabian; Pradas, Marc; Charogiannis, Alexandros; Markides, Christos N; van Wachem, Berend G M; Kalliadasis, Serafim
2016-03-01
We propose consistent scaling of solitary waves on inertia-dominated falling liquid films, which accurately accounts for the driving physical mechanisms and leads to a self-similar characterization of solitary waves. Direct numerical simulations of the entire two-phase system are conducted using a state-of-the-art finite volume framework for interfacial flows in an open domain that was previously validated against experimental film-flow data with excellent agreement. We present a detailed analysis of the wave shape and the dispersion of solitary waves on 34 different water films with Reynolds numbers Re=20-120 and surface tension coefficients σ=0.0512-0.072 N m(-1) on substrates with inclination angles β=19°-90°. Following a detailed analysis of these cases we formulate a consistent characterization of the shape and dispersion of solitary waves, based on a newly proposed scaling derived from the Nusselt flat film solution, that unveils a self-similarity as well as the driving mechanism of solitary waves on gravity-driven liquid films. Our results demonstrate that the shape of solitary waves, i.e., height and asymmetry of the wave, is predominantly influenced by the balance of inertia and surface tension. Furthermore, we find that the dispersion of solitary waves on the inertia-dominated falling liquid films considered in this study is governed by nonlinear effects and only driven by inertia, with surface tension and gravity having a negligible influence.
Time to do more: addressing clinical inertia in the management of type 2 diabetes mellitus.
Strain, W D; Cos, X; Hirst, M; Vencio, S; Mohan, V; Vokó, Z; Yabe, D; Blüher, M; Paldánius, P M
2014-09-01
Clinical inertia, the tendency to maintain current treatment strategies despite results demanding escalation, is thought to substantially contribute to the disconnect between clinical aspirations for patients with diabetes and targets achieved. We wished to explore potential causes of clinical inertia among physicians and people with diabetes. A 20-min online survey of 652 adults with diabetes and 337 treating physicians in six countries explored opinions relating to clinical inertia from both perspectives, in order to correlate perceptions and expectations relating to diagnosis, treatment, diabetes complications and therapeutic escalation. Physicians had low expectations for their patients, despite the belief that the importance of good glycaemic control through lifestyle and pharmacological interventions had been adequately conveyed. Conversely, people with diabetes had, at best, a rudimentary understanding of the risks of complications and the importance of good control; indeed, only a small proportion believed lifestyle changes were important and the majority did not intend to comply. The principal findings of this survey suggest that impairments in communication are at the heart of clinical inertia. This manuscript lays out four key principles that we believe are achievable in all environments and can improve the lives of people with diabetes. Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.
Guo, Siqiu; Zhang, Tao; Song, Yulong; Qian, Feng
2018-04-23
This paper presents a particle swarm tracking algorithm with improved inertia weight based on color features. The weighted color histogram is used as the target feature to reduce the contribution of target edge pixels in the target feature, which makes the algorithm insensitive to the target non-rigid deformation, scale variation, and rotation. Meanwhile, the influence of partial obstruction on the description of target features is reduced. The particle swarm optimization algorithm can complete the multi-peak search, which can cope well with the object occlusion tracking problem. This means that the target is located precisely where the similarity function appears multi-peak. When the particle swarm optimization algorithm is applied to the object tracking, the inertia weight adjustment mechanism has some limitations. This paper presents an improved method. The concept of particle maturity is introduced to improve the inertia weight adjustment mechanism, which could adjust the inertia weight in time according to the different states of each particle in each generation. Experimental results show that our algorithm achieves state-of-the-art performance in a wide range of scenarios.
Santhi, Nayantara; Groeger, John A.; Archer, Simon N.; Gimenez, Marina; Schlangen, Luc J. M.; Dijk, Derk-Jan
2013-01-01
The transition from sleep to wakefulness entails a temporary period of reduced alertness and impaired performance known as sleep inertia. The extent to which its severity varies with task and cognitive processes remains unclear. We examined sleep inertia in alertness, attention, working memory and cognitive throughput with the Karolinska Sleepiness Scale (KSS), the Psychomotor Vigilance Task (PVT), n-back and add tasks, respectively. The tasks were administered 2 hours before bedtime and at regular intervals for four hours, starting immediately after awakening in the morning, in eleven participants, in a four-way cross-over laboratory design. We also investigated whether exposure to Blue-Enhanced or Bright Blue-Enhanced white light would reduce sleep inertia. Alertness and all cognitive processes were impaired immediately upon awakening (pinertia varies with cognitive domain and that it’s spectral/intensity response to light is different from that of sleepiness. That is, just increasing blue-wavelength in light may not be sufficient to reduce sleep inertia. These findings have implications for critical professions like medicine, law-enforcement etc., in which, personnel routinely wake up from night-time sleep to respond to emergency situations. PMID:24260280
Rotational inertia of continents: A proposed link between polar wandering and plate tectonics
Kane, M.F.
1972-01-01
A mechanism is proposed whereby displacement between continents and the earth's pole of rotation (polar wandering) gives rise to latitudinal transport of continental plates (continental drift) because of their relatively greater rotational inertia. When extended to short-term polar wobble, the hypothesis predicts an energy change nearly equivalent to the seismic energy rate.
Importance of upper-limb inertia in calculating concentric bench press force.
Rambaud, Olivier; Rahmani, Abderrahmane; Moyen, Bernard; Bourdin, Muriel
2008-03-01
The purpose of this study was to investigate the influence of upper-limb inertia on the force-velocity relationship and maximal power during concentric bench press exercise. Reference peak force values (Fpeakp) measured with a force plate positioned below the bench were compared to those measured simultaneously with a kinematic device fixed on the barbell by taking (Fpeakt) or not taking (Fpeakb) upper-limb inertia into account. Thirteen men (27.8 +/- 4.1 years, 184.6 +/- 5.5 cm, 99.5 +/- 18.6 kg) performed all-out concentric bench press exercise against 8 loads ranging between 7 and 74 kg. The results showed that for each load, Fpeakb was significantly less than Fpeakp (P force (F0), maximal velocity (V0), optimal velocity (Vopt), and maximal power (Pmax), extrapolated from the force- and power-velocity relationships determined with the kinematic device, were significantly underestimated when upper-limb inertia was ignored. The results underline the importance of taking account of the total inertia of the moving system to ensure precise evaluation of upper-limb muscular characteristics in all-out concentric bench press exercise with a kinematic device. A major application of this study would be to develop precise upper-limb muscular characteristic evaluation in laboratory and field conditions by using a simple and cheap kinematic device.
Effect of liquid inertia on bubble growth in the presence of a magnetic field
International Nuclear Information System (INIS)
Wagner, L.Y.; Lykoudis, P.S.
1977-01-01
Liquid metal bubble growth in the presence of a magnetic field has previously been examined by Lykoudis under the assumption that the process is heat transfer controlled. In the present work, the growth of a bubble under the influence of a magnetic field is considered when the effect of the liquid inertia is included. This yields a better description of the phenomena for liquid metals, due to the greater portion of the growth cycle that is dominated by the liquid inertia forces. The results indicate that liquid inertia can significantly affect the growth of a liquid metal bubble when compared with the heat transfer-controlled case. The overall effect of the magnetic field forces the heat transfer-controlled growth to occur earlier in the life of the bubble. Hence, heat transfer effects dominate the growth stage more as the magnetic field is increased. The inertia effects are damped and, in the limit of high magnetic fields, growth is only heat transfer controlled. The heat transfer estimates made in the fashion of Forster and Zuber indicate that the magnetic field reduces the energy transport in nucleate boiling. 5 figures
Back to inertia : Theoretical implications of alternative styles of logical formalization
Péli, Gabor; Pólos, L.; Hannan, M.T.
This article applies two new criteria, desirability and faithfulness, to evaluate Péli et al.'s (1994) formalization of Hannan and Freeman's structural inertia argument (1984, 1989). We conclude that this formalization fails to meet these criteria. We argue that part of the rational reconstruction
The neutron–proton pairing and the moments of inertia of the rare ...
Indian Academy of Sciences (India)
In this study, the possible effect of the neutron–proton pairing interaction in the heavy nuclei has been investigated in the framework of the BCS model by making a simple approximation. This effect has been searched realistically by calculating the moments of inertia of deformed even–even nuclei. Calculations show that the ...
Effects of artificial dawn on sleep inertia, skin temperature, and the awakening cortisol response
van de Werken, Maan; Gimenez, Marina C.; de Vries, Bonnie; Beersma, Domien G. M.; van Someren, Eus J. W.; Gordijn, Marijke C. M.
P>The effect of artificial dawn during the last 30 min of sleep on subsequent dissipation of sleep inertia was investigated, including possible involvement of cortisol and thermoregulatory processes. Sixteen healthy subjects who reported difficulty with waking up participated in random order in a
Parameter identification and model validation for the piezoelectric actuator in an inertia motor
International Nuclear Information System (INIS)
Hunstig, Matthias; Hemsel, Tobias
2010-01-01
Piezoelectric inertia motors make use of the inertia of a slider to drive the slider by friction contact in a series of small steps which are generally composed of a stick phase and a slip phase. If the best electrical drive signal for the piezoelectric actuator in an inertia motor is to be determined, its dynamical behaviour must be known. A classic dynamic lumped parameter model for piezoelectric actuators is valid only in resonance and, therefore, is not suitable for modelling the actuator in an inertia motor. A reduced dynamic model is used instead. Its parameters are identified using a step response measurement. This model is used to predict the movement of the actuator in response to a velocity-optimized signal introduced in a separate contribution. Results show that the model cannot represent the dynamical characteristics of the actuator completely. For determining voltage signals that let piezoelectric actuators follow a calculated movement pattern exactly, the model can, therefore, only be used with limitations.
Time-dependent quantum fluid density functional theory of hydrogen ...
Indian Academy of Sciences (India)
WINTEC
density functional theory; quantum fluid dynamics. 1. Introduction ... dynamics of strongly non-linear interaction of atoms with intense ... theory and quantum fluid dynamics in real space. .... clear evidence of bond softening since density in the.
Energy Technology Data Exchange (ETDEWEB)
Pacheco, Admilson P.; Ehlers, Ricardo Sandes [Universidade Federal Fluminense, Niteroi, RJ (Brazil); Vitorello, Icaro [Instituto de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil)
1995-12-31
The effect of porosity, and the relation between thermal inertia values and chemical components were determined. The thermal inertia values and chemical components were determined. The thermal inertia determinations were performed using radiometric observations, in the range 8 to 14 {mu}, of the surface temperature variations of the sample, induced by an incident heat flux. The results show that the increase in porosity tends to reduce the thermal inertia values, when the rock is in a dry state. In the water saturation state, the inertia also tends to show small values, only for porous rocks with thermal inertia values larger than the water values. The acid rocks show thermal inertia values smaller than those of the basic rocks. The intermediate and basic rocks show strong positive correlation between thermal inertia and Si O{sub 2}. 7 refs., 3 figs
Clinical inertia in the treatment of hyperglycemia in type 2 diabetes patients in primary care.
Mata-Cases, Manel; Benito-Badorrey, Belén; Roura-Olmeda, Pilar; Franch-Nadal, Josep; Pepió-Vilaubí, Josep Maria; Saez, Marc; Coll-de-Tuero, Gabriel
2013-11-01
To assess clinical inertia, defined as failure to intensify antidiabetic treatment of patients who have not achieved the HbA1c therapeutic goal (≤7%). Multicenter cross-sectional study. Clinical inertia was assessed in a random sample of type 2 diabetes mellitus (T2DM) patients seen in primary care centers. A total of 2783 patients (51.3% males; mean age: 68 [±11.5] years; diabetes duration: 7.1 [±5.6] years; mean HbA1c: 6.8 [±1.5]) were analyzed. Of those, 997 (35.8%) had HbA1c >7%. Treatment was intensified in 66.8% and consisted of: dose increase (40.5%); addition of oral antidiabetic (45.8%); or insulin treatment initiation (3.7%). Mean HbA1c values in patients for whom treatment was intensified vs. non-intensified were 8.4% (±1.2) vs. 8.2% (±1.2), p inertia was detected in 33.2% of patients and diminished along with treatment complexity: lifestyle changes only (38.8%), oral monotherapy (40.3%), combined oral antidiabetics (34.5%), insulin monotherapy (26.1%) and combination of insulin and oral antidiabetics (21.4%). Clinical inertia decreased as HbA1c increased: 37.3% for HbA1c values ranging between 7.1%-8%; 29.4% for the 8.1%-9% HbA1c range and 27.1% for HbA1c ≥9%. Multivariate analysis confirmed that diabetes duration, step of treatment and HbA1c were related to inertia. For each unit of HbA1c increase clinical inertia decreased 47% (OR: 0.53). The retrospective design of the study precluded an accurate investigation about reasons for lack of intensification that could actually be justified by some patient conditions, especially patients' lack of adherence. Clinical inertia affected one third of T2DM patients with poor glycemic control and was greater in patients treated with only lifestyle changes or oral monotherapy. Treatment changes were performed when mean HbA1c values were 1.4 points above therapeutic goals.
Milman, Tal; Joundi, Raed A; Alotaibi, Naif M; Saposnik, Gustavo
2018-06-01
Clinical Inertia is defined as "failure of health care providers to initiate or intensify therapy according to current guidelines". This phenomenon is gaining increasing attention as a major cause of clinicians' failure to adequately manage hypertension, thus leading to an increased incidence of cardiovascular events. We performed a systematic review and meta-analysis of randomized controlled trials to determine whether interventions aimed at reducing clinical inertia in the pharmacological treatment of hypertension improve blood pressure (BP) control. MEDLINE, Embase, and Cochrane Database of Systematic Reviews were searched from the start of their database until October 3, 2017 for the MESH terms "Hypertension" or "Blood Pressure", their subheadings, and the keywords "Therapeutic Inertia" or "Clinical Inertia". Studies were included if they addressed pharmacologic hypertension management, clinical inertia, were randomized controlled trials, reported an outcome describing prescriber behavior, and were available in English. Data for the included studies was extracted by two independent observers. Quality of studies was analyzed using the Cochrane Risk of Bias Assessment. Data was pooled for statistical analysis using both fixed- and random-effects models. The primary study outcome was the percentage of patients achieving blood pressure control as defined by the Joint National Committee guidelines or study authors. Of 474 citations identified, ten met inclusion criteria comprising a total of 26,871 patients, and eight were selected for meta-analysis. Interventions included Physician Education, Physician Reminders, Patient Education, Patient Reminders, Ambulatory BP Monitoring, Digital Medication Offerings, Physician Peer Visits, and Pharmacist-led Counselling. Pooled event rates revealed more patients with controlled BP in the intervention group versus control (55%, 95% CI 46-63% versus 45%, 95% CI 37-53%) and interventions significantly improved the odds of BP
Ogilvie, Gordon I.
2016-06-01
> These lecture notes and example problems are based on a course given at the University of Cambridge in Part III of the Mathematical Tripos. Fluid dynamics is involved in a very wide range of astrophysical phenomena, such as the formation and internal dynamics of stars and giant planets, the workings of jets and accretion discs around stars and black holes and the dynamics of the expanding Universe. Effects that can be important in astrophysical fluids include compressibility, self-gravitation and the dynamical influence of the magnetic field that is `frozen in' to a highly conducting plasma. The basic models introduced and applied in this course are Newtonian gas dynamics and magnetohydrodynamics (MHD) for an ideal compressible fluid. The mathematical structure of the governing equations and the associated conservation laws are explored in some detail because of their importance for both analytical and numerical methods of solution, as well as for physical interpretation. Linear and nonlinear waves, including shocks and other discontinuities, are discussed. The spherical blast wave resulting from a supernova, and involving a strong shock, is a classic problem that can be solved analytically. Steady solutions with spherical or axial symmetry reveal the physics of winds and jets from stars and discs. The linearized equations determine the oscillation modes of astrophysical bodies, as well as their stability and their response to tidal forcing.
Energy Technology Data Exchange (ETDEWEB)
Garcia Velarde, M
1977-07-01
Thermo convective instabilities in horizontal fluid layers are discussed with emphasis on the Rayleigh-Bernard model problem. Steady solutions and time-dependent phenomena (relaxation oscillations and transition to turbulence) are studied within the nonlinear Boussinesq-Oberbeck approximation. Homogeneous steady solutions, limit cycles, and inhomogeneous (ordered) spatial structures are also studied in simple reaction-diffusion systems. Lastly, the non-periodic attractor that appears at large Rayleigh numbers in the truncated Boussinesq-Oberbeck model of Lorenz, is constructed, and a discussion of turbulent behavior is given. (Author) 105 refs.
International Nuclear Information System (INIS)
Garcia Velarde, M.
1977-01-01
Thermoconvective instabilities in horizontal fluid layers are discussed with emphasis on the Rayleigh-Benard model problem. Steady solutions and time-dependent phenomena (relaxation oscillations and transition to turbulence) are studied within the nonlinear Boussinesq-Oberbeck approximation. Homogeneous steady solutions, limit cycles, and inhomogeneous (ordered) spatial structures are also studied in simple reaction-diffusion systems. Lastly, the non-periodic attractor that appears at large Rayleigh numbers in the truncated Boussinesq-Oberbeck model of Lorenz, is constructed, and a discussion of turbulent behavior is given. (author) [es
International Nuclear Information System (INIS)
Garcia Velarde, M.
1977-01-01
Thermo convective instabilities in horizontal fluid layers are discussed with emphasis on the Rayleigh-Bernard model problem. Steady solutions and time-dependent phenomena (relaxation oscillations and transition to turbulence) are studied within the nonlinear Boussinesq-Oberbeck approximation. Homogeneous steady solutions, limit cycles, and inhomogeneous (ordered) spatial structures are also studied in simple reaction-diffusion systems. Lastly, the non-periodic attractor that appears at large Rayleigh numbers in the truncated Boussinesq-Oberbeck model of Lorenz, is constructed, and a discussion of turbulent behavior is given. (Author) 105 refs
The effect of rotatory inertia on the dynamic response of cantilever structures
International Nuclear Information System (INIS)
Lin, Y.J.; Hadjian, A.H.
1977-01-01
For the dynamic response of cantilever beams, the error introduced by the bending theory becomes significant as the ratio of the radius of gyration to the beam length (r/l), exceeds 0.1. In this case, the use of Timoshenko's beam equation becomes more appropriate. This equation includes, in addition to the bending effects, both shear deformation and rotatory inertia effects. In the discrete modeling of beam elements, both the shear deformation and rotatory inertia terms play roles in the mass matrix, while only the shear deformation terms appear in the stiffness matrix. The effect of rotatory inertia on the frequencies and dynamic response of cantilever structures subjected to lateral earthquake excitation is thoroughly studied. This is done by using both the consistent and lumped mass matrices and analytical solution. The beam support is treated either as fixed or elastically restrained to consider soil-structure interaction effects. Since containment structures can be treated as hollow beams, the cantilever beam of uniform cross-section is examined first. For those cases where the ratio of the radius of gyration to beam length lies within the range of interest, all the solutions show that rotatory inertia has an important impact on both the frequencies (other than that of the fundamental mode) and the vertical component of the response. However, as the soil-structure interaction effects become significant rotatory inertia effects become secondary. For shear wall structures used in nuclear power plants, the floors may be treated as rigid diaphragms and the shear walls between floors are usually considered to be beam elements of uniform cross-section
Barton, Anna Beth; Okorodudu, Daniel E; Bosworth, Hayden B; Crowley, Matthew J
2018-01-17
Treatment nonadherence and clinical inertia perpetuate poor cardiovascular disease (CVD) risk factor control. Telemedicine interventions may counter both treatment nonadherence and clinical inertia. We explored why a telemedicine intervention designed to reduce treatment nonadherence and clinical inertia did not improve CVD risk factor control, despite enhancing treatment adherence versus usual care. In this analysis of a randomized trial, we studied recipients of the 12-month telemedicine intervention. This intervention comprised two nurse-administered components: (1) monthly self-management education targeting improved treatment adherence; and (2) quarterly medication management facilitation designed to support treatment intensification by primary care (thereby reducing clinical inertia). For each medication management facilitation encounter, we ascertained whether patients met treatment goals, and if not, whether primary care recommended treatment intensification following the encounter. We assessed disease control associated with encounters, where intensification was/was not recommended. We examined 455 encounters across 182 intervention recipients (100% African Americans with type 2 diabetes). Even after accounting for valid reasons for deferring intensification (e.g., treatment nonadherence), intensification was not recommended in 67.5% of encounters in which hemoglobin A1c was above goal, 72.5% in which systolic blood pressure was above goal, and 73.9% in which low-density lipoprotein cholesterol was above goal. In each disease state, treatment intensification was more likely with poorer control. Despite enhancing treatment adherence, this intervention was unsuccessful in countering clinical inertia, likely explaining its lack of effect on CVD risk factors. We identify several lessons learned that may benefit investigators and healthcare systems.
Partial inertia induces additional phase transition in the majority vote model.
Harunari, Pedro E; de Oliveira, M M; Fiore, C E
2017-10-01
Explosive (i.e., discontinuous) transitions have aroused great interest by manifesting in distinct systems, such as synchronization in coupled oscillators, percolation regime, absorbing phase transitions, and more recently, the majority-vote model with inertia. In the latter, the model rules are slightly modified by the inclusion of a term depending on the local spin (an inertial term). In such a case, Chen et al. [Phys Rev. E 95, 042304 (2017)2470-004510.1103/PhysRevE.95.042304] have found that relevant inertia changes the nature of the phase transition in complex networks, from continuous to discontinuous. Here we give a further step by embedding inertia only in vertices with degree larger than a threshold value 〈k〉k^{*}, 〈k〉 being the mean system degree and k^{*} the fraction restriction. Our results, from mean-field analysis and extensive numerical simulations, reveal that an explosive transition is presented in both homogeneous and heterogeneous structures for small and intermediate k^{*}'s. Otherwise, a large restriction can sustain a discontinuous transition only in the heterogeneous case. This shares some similarities with recent results for the Kuramoto model [Phys. Rev. E 91, 022818 (2015)PLEEE81539-375510.1103/PhysRevE.91.022818]. Surprisingly, intermediate restriction and large inertia are responsible for the emergence of an extra phase, in which the system is partially synchronized and the classification of phase transition depends on the inertia and the lattice topology. In this case, the system exhibits two phase transitions.
Sleep inertia, sleep homeostatic and circadian influences on higher-order cognitive functions.
Burke, Tina M; Scheer, Frank A J L; Ronda, Joseph M; Czeisler, Charles A; Wright, Kenneth P
2015-08-01
Sleep inertia, sleep homeostatic and circadian processes modulate cognition, including reaction time, memory, mood and alertness. How these processes influence higher-order cognitive functions is not well known. Six participants completed a 73-day-long study that included two 14-day-long 28-h forced desynchrony protocols to examine separate and interacting influences of sleep inertia, sleep homeostasis and circadian phase on higher-order cognitive functions of inhibitory control and selective visual attention. Cognitive performance for most measures was impaired immediately after scheduled awakening and improved during the first ~2-4 h of wakefulness (decreasing sleep inertia); worsened thereafter until scheduled bedtime (increasing sleep homeostasis); and was worst at ~60° and best at ~240° (circadian modulation, with worst and best phases corresponding to ~09:00 and ~21:00 hours, respectively, in individuals with a habitual wake time of 07:00 hours). The relative influences of sleep inertia, sleep homeostasis and circadian phase depended on the specific higher-order cognitive function task examined. Inhibitory control appeared to be modulated most strongly by circadian phase, whereas selective visual attention for a spatial-configuration search task was modulated most strongly by sleep inertia. These findings demonstrate that some higher-order cognitive processes are differentially sensitive to different sleep-wake regulatory processes. Differential modulation of cognitive functions by different sleep-wake regulatory processes has important implications for understanding mechanisms contributing to performance impairments during adverse circadian phases, sleep deprivation and/or upon awakening from sleep. © 2015 European Sleep Research Society.
Zero-G experimental validation of a robotics-based inertia identification algorithm
Bruggemann, Jeremy J.; Ferrel, Ivann; Martinez, Gerardo; Xie, Pu; Ma, Ou
2010-04-01
The need to efficiently identify the changing inertial properties of on-orbit spacecraft is becoming more critical as satellite on-orbit services, such as refueling and repairing, become increasingly aggressive and complex. This need stems from the fact that a spacecraft's control system relies on the knowledge of the spacecraft's inertia parameters. However, the inertia parameters may change during flight for reasons such as fuel usage, payload deployment or retrieval, and docking/capturing operations. New Mexico State University's Dynamics, Controls, and Robotics Research Group has proposed a robotics-based method of identifying unknown spacecraft inertia properties1. Previous methods require firing known thrusts then measuring the thrust, and the velocity and acceleration changes. The new method utilizes the concept of momentum conservation, while employing a robotic device powered by renewable energy to excite the state of the satellite. Thus, it requires no fuel usage or force and acceleration measurements. The method has been well studied in theory and demonstrated by simulation. However its experimental validation is challenging because a 6- degree-of-freedom motion in a zero-gravity condition is required. This paper presents an on-going effort to test the inertia identification method onboard the NASA zero-G aircraft. The design and capability of the test unit will be discussed in addition to the flight data. This paper also introduces the design and development of an airbearing based test used to partially validate the method, in addition to the approach used to obtain reference value for the test system's inertia parameters that can be used for comparison with the algorithm results.
Directory of Open Access Journals (Sweden)
Nayantara Santhi
Full Text Available The transition from sleep to wakefulness entails a temporary period of reduced alertness and impaired performance known as sleep inertia. The extent to which its severity varies with task and cognitive processes remains unclear. We examined sleep inertia in alertness, attention, working memory and cognitive throughput with the Karolinska Sleepiness Scale (KSS, the Psychomotor Vigilance Task (PVT, n-back and add tasks, respectively. The tasks were administered 2 hours before bedtime and at regular intervals for four hours, starting immediately after awakening in the morning, in eleven participants, in a four-way cross-over laboratory design. We also investigated whether exposure to Blue-Enhanced or Bright Blue-Enhanced white light would reduce sleep inertia. Alertness and all cognitive processes were impaired immediately upon awakening (p<0.01. However, alertness and sustained attention were more affected than cognitive throughput and working memory. Moreover, speed was more affected than accuracy of responses. The light conditions had no differential effect on performance except in the 3-back task (p<0.01, where response times (RT at the end of four hours in the two Blue-Enhanced white light conditions were faster (200 ms than at wake time. We conclude that the effect of sleep inertia varies with cognitive domain and that it's spectral/intensity response to light is different from that of sleepiness. That is, just increasing blue-wavelength in light may not be sufficient to reduce sleep inertia. These findings have implications for critical professions like medicine, law-enforcement etc., in which, personnel routinely wake up from night-time sleep to respond to emergency situations.
Directory of Open Access Journals (Sweden)
Tanwiwat Jaikuna
2017-02-01
Full Text Available Purpose: To develop an in-house software program that is able to calculate and generate the biological dose distribution and biological dose volume histogram by physical dose conversion using the linear-quadratic-linear (LQL model. Material and methods : The Isobio software was developed using MATLAB version 2014b to calculate and generate the biological dose distribution and biological dose volume histograms. The physical dose from each voxel in treatment planning was extracted through Computational Environment for Radiotherapy Research (CERR, and the accuracy was verified by the differentiation between the dose volume histogram from CERR and the treatment planning system. An equivalent dose in 2 Gy fraction (EQD2 was calculated using biological effective dose (BED based on the LQL model. The software calculation and the manual calculation were compared for EQD2 verification with pair t-test statistical analysis using IBM SPSS Statistics version 22 (64-bit. Results: Two and three-dimensional biological dose distribution and biological dose volume histogram were displayed correctly by the Isobio software. Different physical doses were found between CERR and treatment planning system (TPS in Oncentra, with 3.33% in high-risk clinical target volume (HR-CTV determined by D90%, 0.56% in the bladder, 1.74% in the rectum when determined by D2cc, and less than 1% in Pinnacle. The difference in the EQD2 between the software calculation and the manual calculation was not significantly different with 0.00% at p-values 0.820, 0.095, and 0.593 for external beam radiation therapy (EBRT and 0.240, 0.320, and 0.849 for brachytherapy (BT in HR-CTV, bladder, and rectum, respectively. Conclusions : The Isobio software is a feasible tool to generate the biological dose distribution and biological dose volume histogram for treatment plan evaluation in both EBRT and BT.
Double-diffusive convection in a Darcy porous medium saturated with a couple-stress fluid
International Nuclear Information System (INIS)
Malashetty, M S; Kollur, Premila; Pal, Dulal
2010-01-01
The onset of double-diffusive convection in a couple-stress fluid-saturated horizontal porous layer is studied using linear and weak nonlinear stability analyses. The modified Darcy equation that includes the time derivative term and the inertia term is used to model the momentum equation. The expressions for stationary, oscillatory and finite-amplitude Rayleigh number are obtained as a function of the governing parameters. The effect of couple-stress parameter, solute Rayleigh number, Vadasz number and diffusivity ratio on stationary, oscillatory and finite-amplitude convection is shown graphically. It is found that the couple-stress parameter and the solute Rayleigh number have a stabilizing effect on stationary, oscillatory and finite-amplitude convection. The diffusivity ratio has a destabilizing effect in the case of stationary and finite-amplitude modes, with a dual effect in the case of oscillatory convection. The Vadasz number advances the onset of oscillatory convection. The heat and mass transfer decreases with an increase in the values of couple-stress parameter and diffusivity ratio, while both increase with an increase in the value of the solute Rayleigh number.
Relativistic viscoelastic fluid mechanics
International Nuclear Information System (INIS)
Fukuma, Masafumi; Sakatani, Yuho
2011-01-01
A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.
Relativistic viscoelastic fluid mechanics.
Fukuma, Masafumi; Sakatani, Yuho
2011-08-01
A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.
Stenger, M. B.; Hargens, A. R.; Dulchavsky, S. A.; Arbeille, P.; Danielson, R. W.; Ebert, D. J.; Garcia, K. M.; Johnston, S. L.; Laurie, S. S.; Lee, S. M. C.;
2017-01-01
Introduction. NASA's Human Research Program is focused on addressing health risks associated with long-duration missions on the International Space Station (ISS) and future exploration-class missions beyond low Earth orbit. Visual acuity changes observed after short-duration missions were largely transient, but now more than 50 percent of ISS astronauts have experienced more profound, chronic changes with objective structural findings such as optic disc edema, globe flattening and choroidal folds. These structural and functional changes are referred to as the visual impairment and intracranial pressure (VIIP) syndrome. Development of VIIP symptoms may be related to elevated intracranial pressure (ICP) secondary to spaceflight-induced cephalad fluid shifts, but this hypothesis has not been tested. The purpose of this study is to characterize fluid distribution and compartmentalization associated with long-duration spaceflight and to determine if a relation exists with vision changes and other elements of the VIIP syndrome. We also seek to determine whether the magnitude of fluid shifts during spaceflight, as well as any VIIP-related effects of those shifts, are predicted by the crewmember's pre-flight status and responses to acute hemodynamic manipulations, specifically posture changes and lower body negative pressure. Methods. We will examine a variety of physiologic variables in 10 long-duration ISS crewmembers using the test conditions and timeline presented in the figure below. Measures include: (1) fluid compartmentalization (total body water by D2O, extracellular fluid by NaBr, intracellular fluid by calculation, plasma volume by CO rebreathe, interstitial fluid by calculation); (2) forehead/eyelids, tibia, and calcaneus tissue thickness (by ultrasound); (3) vascular dimensions by ultrasound (jugular veins, cerebral and carotid arteries, vertebral arteries and veins, portal vein); (4) vascular dynamics by MRI (head/neck blood flow, cerebrospinal fluid
International Nuclear Information System (INIS)
Shen, M.C.; Ebel, D.
1987-01-01
In this paper some new results concerning magnetohydrodynamic (MHD) equations with the Hall current (HC) term in the Ohm's law are presented. For the cylindrical pinch of a compressible HC fluid, it is found that for large time and long wave length the solution to the governing equations exhibits the behavior of solitons as in the case of an ideal MHD model. In some special cases, the HC model appears to be better posed. An open question is whether a simple toroidal equilibrium of an HC fluid with resistivity and viscosity exists. The answer to this question is affirmative if the prescribed velocity on the boundary has a small norm. Furthermore, the equilibrium is also linearly and nonlinearly stable
Generalized extended Navier-Stokes theory: multiscale spin relaxation in molecular fluids.
Hansen, J S
2013-09-01
This paper studies the relaxation of the molecular spin angular velocity in the framework of generalized extended Navier-Stokes theory. Using molecular dynamics simulations, it is shown that for uncharged diatomic molecules the relaxation time decreases with increasing molecular moment of inertia per unit mass. In the regime of large moment of inertia the fast relaxation is wave-vector independent and dominated by the coupling between spin and the fluid streaming velocity, whereas for small inertia the relaxation is slow and spin diffusion plays a significant role. The fast wave-vector-independent relaxation is also observed for highly packed systems. The transverse and longitudinal spin modes have, to a good approximation, identical relaxation, indicating that the longitudinal and transverse spin viscosities have same value. The relaxation is also shown to be isomorphic invariant. Finally, the effect of the coupling in the zero frequency and wave-vector limit is quantified by a characteristic length scale; if the system dimension is comparable to this length the coupling must be included into the fluid dynamical description. It is found that the length scale is independent of moment of inertia but dependent on the state point.
International Nuclear Information System (INIS)
Granger, R.A.
1985-01-01
This text offers the most comprehensive approach available to fluid mechanics. The author takes great care to insure a physical understanding of concepts grounded in applied mathematics. The presentation of theory is followed by engineering applications, helping students develop problem-solving skills from the perspective of a professional engineer. Extensive use of detailed examples reinforces the understanding of theoretical concepts
González-Clemente, José Miguel; Font, Beatriu; Lahoz, Raquel; Llauradó, Gemma; Gambús, Gemma
2014-06-06
To study clinical inertia in the management of oral hypoglycemic agents (OHA) in non-insulin treated patients with type 2 diabetes mellitus (T2DM) in Spain. Epidemiological, cross-sectional, retrospective (2 years), multicenter study. Clinical inertia was measured as the total number of patients without OHA treatment intensification divided by the total number of patients with inadequate HbA1c values (≥7%), multiplied by 100. Total clinical inertia (TCI) was the absence of OHA treatment intensification in all visits with a HbA1c≥7% values in the previous 2 years; partial clinical inertia (PCI) occurred when this absence only occurred in some of these visits. We assessed OHA treatment compliance with the Morisky-Green test. We included 2,971 patients, 1,416 adequately controlled (HbA1c<7%) and 1,555 inadequately controlled (HbA1c≥7%). PCI prevalence was 52.5%(95% confidence interval [95% CI] 52.4-52.6%) while TCI prevalence was 12.8% (95% CI 12.2-13.8%). PCI was lower in patients adequately controlled as compared with those inadequately controlled (31.4% vs. 71.8%; P<.001). PCI was associated with sedentary lifestyle, hypertension and higher prevalence of micro and macrovascular complications. Only 38.0% of patients were compliant with the OHA treatment, being this percentage even lower in subjects with ICP. Two variables were independently associated with ICP: female sex (odds ratio [OR] 1.43; 95% CI 1.09-1.86%) and a shorter duration of DM2 (OR 0.98; 95% CI 0.95-0.99). One out of 2 patients with T2DM and treated with OHA without insulin suffer from PCI. Only 4 out of 10 patients are compliant with OHA treatment. Female sex and a shorter duration of T2DM are independently associated with PCI. Copyright © 2012 Elsevier España, S.L. All rights reserved.
The effects of one-body dissipation and collective inertias in heavy-ion scattering and fusion
International Nuclear Information System (INIS)
Stryjewski, J.S.
1989-01-01
A classical dynamical model of heavy ion scattering and fusion is presented. The model includes deformations, deformation-dependent inertias and one-body friction in both the entrance and exit channels. The deformation-dependent inertias are calculated using a hydrodynamic approach and the one-body friction is determined with the classical wall friction formalism. This model is used to study the effects of one-body friction and collective inertias on strongly damped heavy ion reactions and fusion. Quantum-mechanical calculations suggest that the strength of classical one-body friction, as calculated by the wall formalism, is too large by a factor of 3. Therefore, the fusion excitation functions for the reactions: 16 O + 16 O, 28 Si + 28 Si, 40 Ca + 40 Ca and 56 Fe + 56 Fe are calculated and compared with similar calculations in which the strength of the wall friction has been reduced by a factor of 3. Calculations using the full wall friction reproduce the experimental fusion excitation functions more accurately than calculations using the weaker wall friction. Also, because hydrodynamical inertias are the smallest possible classical inertias, the fusion excitation functions for: 16 O + 16 O, 28 Si + 28 Si, 40 Ca + 40 Ca and 56 Fe + 56 Fe are calculated with the size of the collective inertias increased by a factor of 2 over the hydrodynamical values. Once again, calculations using hydrodynamical collective inertias reproduce the experimental fusion excitation functions more accurately than calculations using the larger collective inertias. The effects of one-body friction and collective inertias on heavy ion scattering are also investigated; reaction times, scattering angles and energy loss are determined as functions of energy and angular momentum for the reactions 98 Mo + 98 Mo and 238 U + 238 U
Energy Technology Data Exchange (ETDEWEB)
Cowan, Nicolas B. [Center for Interdisciplinary Exploration and Research in Astrophysics and Department of Physics and Astronomy, Northwestern University, 2131 Tech Drive, Evanston, IL 60208 (United States); Voigt, Aiko [Max Planck Institute for Meteorology, Bundesstr. 53, D-20146 Hamburg (Germany); Abbot, Dorian S., E-mail: n-cowan@nortwestern.edu [Department of Geophysical Sciences, University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60637 (United States)
2012-09-20
In order to understand the climate on terrestrial planets orbiting nearby Sun-like stars, one would like to know their thermal inertia. We use a global climate model to simulate the thermal phase variations of Earth analogs and test whether these data could distinguish between planets with different heat storage and heat transport characteristics. In particular, we consider a temperate climate with polar ice caps (like the modern Earth) and a snowball state where the oceans are globally covered in ice. We first quantitatively study the periodic radiative forcing from, and climatic response to, rotation, obliquity, and eccentricity. Orbital eccentricity and seasonal changes in albedo cause variations in the global-mean absorbed flux. The responses of the two climates to these global seasons indicate that the temperate planet has 3 Multiplication-Sign the bulk heat capacity of the snowball planet due to the presence of liquid water oceans. The obliquity seasons in the temperate simulation are weaker than one would expect based on thermal inertia alone; this is due to cross-equatorial oceanic and atmospheric energy transport. Thermal inertia and cross-equatorial heat transport have qualitatively different effects on obliquity seasons, insofar as heat transport tends to reduce seasonal amplitude without inducing a phase lag. For an Earth-like planet, however, this effect is masked by the mixing of signals from low thermal inertia regions (sea ice and land) with that from high thermal inertia regions (oceans), which also produces a damped response with small phase lag. We then simulate thermal light curves as they would appear to a high-contrast imaging mission (TPF-I/Darwin). In order of importance to the present simulations, which use modern-Earth orbital parameters, the three drivers of thermal phase variations are (1) obliquity seasons, (2) diurnal cycle, and (3) global seasons. Obliquity seasons are the dominant source of phase variations for most viewing angles. A
International Nuclear Information System (INIS)
Cowan, Nicolas B.; Voigt, Aiko; Abbot, Dorian S.
2012-01-01
In order to understand the climate on terrestrial planets orbiting nearby Sun-like stars, one would like to know their thermal inertia. We use a global climate model to simulate the thermal phase variations of Earth analogs and test whether these data could distinguish between planets with different heat storage and heat transport characteristics. In particular, we consider a temperate climate with polar ice caps (like the modern Earth) and a snowball state where the oceans are globally covered in ice. We first quantitatively study the periodic radiative forcing from, and climatic response to, rotation, obliquity, and eccentricity. Orbital eccentricity and seasonal changes in albedo cause variations in the global-mean absorbed flux. The responses of the two climates to these global seasons indicate that the temperate planet has 3× the bulk heat capacity of the snowball planet due to the presence of liquid water oceans. The obliquity seasons in the temperate simulation are weaker than one would expect based on thermal inertia alone; this is due to cross-equatorial oceanic and atmospheric energy transport. Thermal inertia and cross-equatorial heat transport have qualitatively different effects on obliquity seasons, insofar as heat transport tends to reduce seasonal amplitude without inducing a phase lag. For an Earth-like planet, however, this effect is masked by the mixing of signals from low thermal inertia regions (sea ice and land) with that from high thermal inertia regions (oceans), which also produces a damped response with small phase lag. We then simulate thermal light curves as they would appear to a high-contrast imaging mission (TPF-I/Darwin). In order of importance to the present simulations, which use modern-Earth orbital parameters, the three drivers of thermal phase variations are (1) obliquity seasons, (2) diurnal cycle, and (3) global seasons. Obliquity seasons are the dominant source of phase variations for most viewing angles. A pole-on observer
Osataphan, Soravis; Chalermchai, Thep; Ngaosuwan, Kanchana
2017-03-01
Clinical inertia is a failure to intensify treatment according to evidence-based guidelines, and can have both short- and long-term adverse effects for type 2 diabetes (T2D). The aim of the present study was to demonstrate the effects of clinical inertia on glycemic control and diabetes-related complications. A retrospective cohort study was conducted at a university-based hospital in Thailand. Medical records were evaluated retrospectively from January 2010 to December 2014. Patients were classified into two groups: clinical inertia and non-inertia. Clinical inertia was defined as failure to initiate insulin within 3 months in patients with HbA1c ≥9 % who were already taking two oral antidiabetic agents. From 1206 records, 98 patients with mean HbA1c of 10.3 % were identified and enrolled in the study. The median follow-up time of these patients was 29.5 months and 68.4 % were classified into the clinical inertia group. The mean (± SD) HbA1c decrement in the clinical inertia and non-inertia groups was 0.82 ± 1.50 % and 3.02 ± 1.80 %, respectively, at 6 months (P inertia was associated with a significantly shorter median time to progression of diabetic retinopathy (DR); log rank test, P = 0.02 and a higher incidence of DR progression (10 vs 2.2 cases per 1000 person-months; P = 0.003). The adjusted incidence rate ratio for DR progression in the clinical inertia group was 4.92 (95 % confidence interval 1.11-21.77; P = 0.036). Being treated by general practitioners was the strongest risk factor associated with clinical inertia. Clinical inertia can cause persistently poor glycemic control and speed up the progression of DR in T2D. © 2016 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.
International Nuclear Information System (INIS)
Adeev, G.; Trunova, T.
1982-01-01
The effective moments of inertia of pre-actinide nuclei with 73< or =Z< or =85 are calculated in the droplet model. In contrast to studies carried out previously, the influence of the diffuseness of the nuclear surface and the nonuniformity of the distribution of nucleon density was taken into account both in calculation of the saddle-point configurations and directly in calculation of the effective moments of inertia of the fissioning nuclei. The results are compared with the moments of inertia calculated in the liquid-drop model and with experimental data
Fluid dynamics of dilatant fluid
DEFF Research Database (Denmark)
Nakanishi, Hiizu; Nagahiro, Shin-ichiro; Mitarai, Namiko
2012-01-01
of the state variable, we demonstrate that the model can describe basic features of the dilatant fluid such as the stress-shear rate curve that represents discontinuous severe shear thickening, hysteresis upon changing shear rate, and instantaneous hardening upon external impact. An analysis of the model...
Fast fluid registration of medical images
DEFF Research Database (Denmark)
Bro-Nielsen, Morten; Gramkow, Claus
1996-01-01
This paper offers a new fast algorithm for non-rigid viscous fluid registration of medical images that is at least an order of magnitude faster than the previous method by (Christensen et al., 1994). The core algorithm in the fluid registration method is based on a linear elastic deformation...
Sustainable sewage management and the inertia to change
Öberg, G.
2012-12-01
Increasing economic costs and environmental concerns have led to that planners around the world are progressively questioning the prevailing sewage management paradigm, calling for a shift in the hydrosocial contract to embrace more sustainable solutions, to be based on closed-loops rather than linear end-of-pipe solutions. Despite considerable attention to the technical possibilities for delivering sewage services in a more integrated and sustainable fashion, shifts in planning and management have been slow. Based on an extensive study of Australian cities, Brown et al (2009) have developed a model with six transitional stages and argue that "while there may be cognitive changes (best practice thinking such as water sustainable urban design), there has not been sufficient normative and regulative change to support new practice." They contrast three historic transition stages with three successive sustainable stages. Unfortunately, the study ends in a rather vague outline of "the Water Sensitive City", with little sign-posts indicating how one might transition to this seemingly utopian last stage. In the present paper, we discuss the normative tensions created between the different actors in this increasingly complex playing field, who represent different and often competing values. We suggest that cities have difficulties transitioning from the old contract to one of the newer ones because the hydro-social contract promised by these new stages create normative tensions not only between the new and the old, but also between what one might call different types of environmentalists: naturalists and pragmatists. The naturalists, who for example are very voiced in several cities along the North American west coast, tend to embrace the perception of Nature described by environmental historians as Untouched Wilderness, where technology is pinpointed as the root of the problems. In contrast, the other side lean more on the idea of modernity, with a more pragmatic approach
Ruban, Anatoly I
This is the first book in a four-part series designed to give a comprehensive and coherent description of Fluid Dynamics, starting with chapters on classical theory suitable for an introductory undergraduate lecture course, and then progressing through more advanced material up to the level of modern research in the field. The present Part 1 consists of four chapters. Chapter 1 begins with a discussion of Continuum Hypothesis, which is followed by an introduction to macroscopic functions, the velocity vector, pressure, density, and enthalpy. We then analyse the forces acting inside a fluid, and deduce the Navier-Stokes equations for incompressible and compressible fluids in Cartesian and curvilinear coordinates. In Chapter 2 we study the properties of a number of flows that are presented by the so-called exact solutions of the Navier-Stokes equations, including the Couette flow between two parallel plates, Hagen-Poiseuille flow through a pipe, and Karman flow above an infinite rotating disk. Chapter 3 is d...
Energy Technology Data Exchange (ETDEWEB)
Jain, Shweta; Sharma, Prerana [Physics Department, Ujjain Engineering College, Ujjain, MP-456010 (India); Kaothekar, Sachin [Physics Department, Mahakal Institute of Technology, Ujjain, MP-456664 (India); Chhajlani, R. K., E-mail: sackaothekar@gmail.com [Retired, School of Studies in Physics, Vikram University Ujjain, MP-456010 (India)
2016-10-01
The thermal instability of an infinite homogeneous, thermally conducting, and rotating plasma, incorporating finite electrical resistivity, finite electron inertia, and an arbitrary radiative heat-loss function in the presence of finite Larmor radius corrections and Hall current, has been studied. Analysis has been made with the help of linearized magnetohydrodynamics (MHD) equations. A general dispersion relation is obtained using the normal mode analysis method, and the dispersion relation is discussed for longitudinal propagation and transverse propagation separately. The dispersion relation has been solved numerically to obtain the dependence of the growth rate on the various parameters involved. The conditions of modified thermal instability and stability are discussed in the different cases of interest.