133 research outputs found
Transporte no local del calor en plasmas
No full textFil: Minotti, Fernando Oscar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Transporte no local del calor en plasmas
No full textFil: Minotti, Fernando Oscar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Scalar-tensor theories and asymmetric resonant cavities
No full textThe recently published experimental results indicate the appearance of unusual forces on asymmetric, electromagnetic resonant cavities. It is argued here that a particular class of scalar-tensor theories of gravity could account for this effect.Fil: Minotti, Fernando Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; Argentin
Evaluation of the Anomalous Force Detected in the Datta, Yin and Vargas Experiment, According to Mbelek and Lachièze-Rey Scalar-Tensor Theory of Gravitation
No full textAn analysis is presented of the experiment by Datta, Yin and Vargas in the light of the Mbelek and Lachieze-Rey scalar-tensor theory of gravitation, showing that this theory reproduces the magnitude and sign of the measured anomalous weight increment of conducting balls immersed in an inhomogeneous electric field.Fil: Minotti, Fernando Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; Argentin
Possible Means of Electrostatic Propulsion According to the Mbelek–Lachièze-Rey Scalar-Tensor Theory of Gravitation
No full textAs was shown recently, the scalar-tensor theory of gravitation proposed by Mbelek and Lachièze-Rey allows for a possible explanation of the forces reported in asymmetric microwave cavities. We show here that the theory in its revised version predicts a much simpler way of producing thrust by electrostatic means. We here briefly present the equations and derivations indicating that a constant force is predicted for a spherical capacitor with an asymmetric mass distribution, kept at constant voltage. Apart form other practical implications, this particular prediction, and a complementary proposal in which the spherical capacitor takes the place of the large mass in a Cavendish-like experiment, provides an additional possibility of experimentally testing this particular scalar-tensor gravitational theory.Fil: Minotti, Fernando Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; Argentin
Dinámica del fenómeno de extrusión en flujos lentos no newtonianos
No full textEn este trabajo se estudia el problema de la extrusión de un líquido muy viscoso con reología no newtoniana. Se obtienen soluciones válidas en el entorno de la desembocadura, que resultan ser autosimilares de segunda especieFil: Minotti, Fernando Oscar. Universidad de Buenos Aires - CONICET. Instituto de Física del Plasma (INFIP). Buenos Aires. ArgentinaFil: Vieytes, Roberto. Universidad de Buenos Aires - CONICET. Instituto de Física del Plasma (INFIP). Buenos Aires. ArgentinaFil: Gratton, Julio. Universidad de Buenos Aires - CONICET. Instituto de Física del Plasma (INFIP). Buenos Aires. Argentin
Effects on light propagating in an electromagnetized vacuum, as predicted by a particular class of scalar tensor theory of gravitation
No full textThe effect of static electromagnetic fields on the propagation of light is analyzed in the context of a particular class of scalar–tensor gravitational theories. It is found that for appropriate field configurations and light polarization, anomalous amplitude variations of the light as it propagates in either a magnetized or an electrified vacuum are strong enough to be detectable in relatively simple laboratory experiments.Fil: Raptis, T. E.. National Center for Science and Research ‘Demokritos’; GreciaFil: Minotti, Fernando Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; Argentin
Revaluation of Mbelek and Lachièze-Rey scalar-tensor theory of gravitation to explain the measured forces in asymmetric resonant cavities
No full textThe scalar-tensor theory of gravitation proposed by Mbelek and Lachièze-Rey has been previously shown to lead to a possible explanation of the forces measured in asymmetric resonant microwave cavities. However, in the derivation of the equations from the action principle some inconsistencies were observed, like no need to vary the electromagnetic invariant in a scalar source term. Also, the forces obtained were too high, in view of reconsideration of the experiments originally reported and of newly published results. In the present work, the equations are re-derived using the full variation of the action, and also the constant of the theory re-evaluated employing the condition that no anomalous gravitational effects are produced by the Earth’s magnetic field. It is shown that the equations originally employed were correct, and that the newly evaluated constant gives the correct magnitude for the forces recently reported.Fil: Minotti, Fernando Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; Argentin
Determination of the instantaneous forces on flapping wings from a localized fluid velocity field
No full textExpressions are derived to relate the instantaneous pressure force on a flapping wing to the velocity field on a plane at the trailing edge and on a highly localized region around and near the wing, valid when the vortex sheet is thin. In its more practical version, the formalism is applicable to wings with close to two-dimensional geometry and has the advantage of not using spatial derivatives, but only a time derivative of a surface integral of the velocity. In the purely two-dimensional case, the expression obtained is used to justify a much simpler one that only requires the evaluation of the time derivative of the wing circulation. A comparison with a numerical simulation in a two-dimensional case shows a good representation of the forces, even with the most simplified expression, when the condition of a thin wake is met. Other examples are shown in which the wake is not thin in order to explore the limitations of the formalism. It is found in these cases that the thrust is sometimes not so well reproduced, with a tendency to be overestimated, while the lift is generally better reproduced. Remarkably, the simpler expression reproduces rather acceptably the phase and amplitude of both thrust and lift in all cases. © 2011 American Institute of Physics.Fil: Minotti, Fernando Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; Argentin
Aharonov–Bohm Electrodynamics in Material Media: A Scalar e.m. Field Cannot Cause Dissipation in a Medium
No full textIn the extension of Maxwell equations based on the Aharonov–Bohm Lagrangian, the e.m. field has an additional degree of freedom, namely, a scalar field generated by charge and currents that are not locally conserved. We analyze the propagation of this scalar field through two different media (a pure dielectric and an ohmic conductor) and study its property over a frequency range where the properties of the media are frequency-independent. We find that an electromagnetic (e.m.) scalar wave cannot propagate in a material medium. If a scalar wave in vacuum impinges on a material medium it is reflected, at most exciting in the medium a pure “potential” wave (which we also call a “gauge” wave) propagating at c, the speed of light in vacuum, with a vector potential whose Fourier amplitude is related to that of the scalar potential by (Formula presented.), where (Formula presented.).Fil: Minotti, Fernando Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; ArgentinaFil: Modanese, Giovanni. Free University of Bozen-Bolzano; Itali
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