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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 10 (1988), S. 229-234 
    ISSN: 0392-6737
    Keywords: Steady-state electromagnetic fields ; electromagnetic induction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Lo scópo di questo lavoro è di chiarire vari seri errori, che sono stati fatti durante l'analisi di due esperimenti collegati alla correttezza della legge di forza di Biot-Savart-Lorentz. All'inizio nell'esperimento MIT, attuato da Graneauet al., si dichiara che il momento calcolato, impartito a un pendolo a impulso elettrodinamico, usando la legge della forza di BSL, è maggiore del 43% del momento misurato sperimentalmente del pendolo a schema pi. Abbiamo trovato che questa discrepanza, usando i dati di Graneauet al., è dovuta all'uso di un valore sbagliato per il parametro della costante del tempo introdotto nella formula della corrente. In più, come Graneau, Pappas, sebbene affermi che tutta l'energia disponibile viene dissipata per riscaldamento di Joule, considera che tutto il momento del pendolo sia impartito al momento del campo portando un'enorme quantità di energia irraggiata dal campo, il che è anche completamente errato.
    Abstract: Резюме Цель этой статьи обсудить различньіе серьезньіе ошибки, которьіе возникли при анализе двух экспериментов, связанньіх с корректностью закона для сильі Вио-Савара-Лоренца. Во-первьіх, в МІТ эксперименте, вьшолненном Гренау и лр., авторьі утверждают, что вьічисленньій импульс, передаваемьій электромагнитному импульсному маятнику, с использованием закона для сильі Био-Савара-Лоренца, на 43% больше, чем зкспериментально измеренньій импульс маятника. Мьі получаем, что это расхождение, используя наши собственньіе данньіе, является результатом теоретических вьічислений с использованием формульі для тока, которьій вообще не соответствует экспериментальньім данньім. Кроме того, они рассматривают, что импульс маятника передается в импульс поля, что приводит к очень большой велчине энергии излучения поля, которая также является полностью ошибочной.
    Notes: Summary The purpose of this paper is to cast light on various serious mistakes which have been involved during the analysis of two experiments, related to the correctness of the Biot-Savart-Lorentz force law. At first in the MIT experiment, carried out by Graneauet al., they claim that the calculated momentum, imparted to an electrodynamic-impulse pendulum, using the BSL force law, is 43% larger than the experimentally measured momentum of the pi-frame pendulum. We have found that this discrepancy, using their own data,is due to the use of a wrong value for the time constant parameter introduced in the current formula. In addition Pappas, like Graneau, although states that all the available energy is dissipated to Joule heating, considers that all the pendulum momentum is imparted to field momentum yielding an enormous amount of field-radiated energy, which is also completely wrong.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 11 (1989), S. 651-653 
    ISSN: 0392-6737
    Keywords: Electromagnetic waves: theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary This paper is intended to elucidate various disputed points discussed in a latter by P. N. Graneau relative to our criticism with respect to his work on the analysis of the electromagnetic-impulse pendulum. The main point of this note is to emphasize that the recoiling momentum of the projectile, in the electromagnetic-impulse pendulum, goes to the fixed frame and not to the radiated field.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 13 (1991), S. 1093-1099 
    ISSN: 0392-6737
    Keywords: Classical electromagnetism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary In this paper we clarify the sources of radiation in a number of experiments, concerning the electromagnetic impulse pendulum, carried out by various authors. The calculated radiated energy was found to be negligible, in all cases, compared to the energy stored in their systems, in contradiction to their claim. We elucidate the way by which Newton's third law is applicable and how the reaction force of the moving pendulum is transferred to the stationary frame. In the MIT experiment of Graneauet al., average values for quantities like the time constant, resistance etc. are given ignoring their standard deviations. Calculating and taking into account their errors, due to their dependence on the temperature, we found agreement between the theoretical and experimental values of the pendulum momentum.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physics Letters A 140 (1989), S. 85-89 
    ISSN: 0375-9601
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 48 (1982), S. 13-24 
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Ground-state energy studies are carried out for liquid3He based on a correlated wave function which incorporates the Feynman-Cohen backflow correlation operator. Applying a lowest order constrained variation (LOCV) method, calculations have been performed for a number of realistic potentials. Our results indicate an improvement over those obtained by other LOCV calculations performed using the Jastrow ansatz and are in good agreement with other calculations involving higher order terms.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 107 (1984), S. 313-322 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The finite difference approximation technique using the explicit method is used for solving the unsteady flow of an electrically conducting viscous and incompressible fluid, subjected to a normal homogenous magnetic field. The flow is confined on one side of a non-magnetic infinite limiting surface (wall) which is initially at rest and then is suddenly accelerated in its own plane with a velocity which is a general function of time. The wall is porous and we assume that the Prandtl number of the fluid corresponds to the case of water and that the magnetic Prandtl number is equal to one. Quantitative discussion of the results is presented for the case of uniformly accelerated motion of the wall.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 113 (1985), S. 281-288 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Unsteady two-dimensional flow of a viscous, incompressible and electrically conducting fluid which is confined on one side of a semi-infinite wall, in presence of a transverse magnetic field is investigated. The wall is initially at rest and then it is suddenly accelerated in its own plane with a velocity which is an arbitrary function of the time. Solution of the problem is obtained, for two particular cases, i.e., corresponding to two free-stream velocities, with the help of the finite difference approximation technique using the explicit method for uniformly accelerated motion of the wall.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 115 (1985), S. 185-194 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The problem of unsteady hydromagnetic axial flow near the porous surface of a sphere or a cylinder is studied numerically. The fluid is considered to be electrically conducting, viscous and incompressible subjected to a magnetic field. Results are presented for the case of injected or sucked fluid with a constant velocity through the porous surfaces. The magnetic Prandtl number is set equal to one, while the magnetic Reynolds number is taken to be small enough so that the inducted magnetic field is negligible.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 161 (1989), S. 17-25 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This paper presents the study of the flow and heat-transfer characteristics in the unsteady flow of liquid metals due to a rotating disk subjected to a transverse magnetic field. The effects of the magnetic field are studied for various Prandtl numbers when the surface of the disk is subjected to cooling or heating. Numerical calculations have been carried out applying a finite difference approximation. It is found that as the magnetic parameter increases the velocities decrease while the temperature increases. Imposing suction the velocities increase while the temperature decreases. As the Prandtl number increases the temperature decreases. The increase of the magnetic parameter to values larger than 7.5 does not cause any variation to the velocities and temperature. Results are also presented for the heat-transfer rate and the displacement and momentum thickness.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 18 (1994), S. 257-271 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In this paper a new, highly accurate method called PH is presented for the numerical integration of partial differential equations. The method is applied for the solution of the one-dimensional diffusion equation. Upon integrating the equation within a subdomain of space and time using the prismoidal approximation, a three-point implicit scheme is obtained with a truncation error of order O(k4, h6), where k and h represent the time and space steps respectively. The method is stable under the condition s = αk/h2 ≤ S(δ), where the function S(δ) increases as the parameter δ decreases from 1/12 to negative values. In practice the method behaves as unconditionally stable upon choosing an appropriate value for δ. A new formula is also adopted for the implementation of a Neumann boundary condition, introducing a truncation error of order O(h4). Numerical solutions are obtained incorporating Dirichlet and Neumann boundary conditions. The results prove that our method is far more accurate than any other-implicit or explicit method.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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