Papers published by A. K. T. Assis (artigos
publicados por A. K. T. Assis).
All papers are in PDF format (todos os artigos estão em formato PDF).
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First we present papers in English , then in Portuguese and finally Miscellaneous Publications (Inicialmente apresentamos os artigos em inglês , depois em português e finalmente publicações extras).
(A) Papers in English (artigos em inglês):
97. A. K. T. Assis, J. E. A. Ribeiro and A.
Vannucci, “The field concepts of Faraday and Maxwell,”
in: Trends in Physics – Festschrift in Homage to Prof. José Maria Filardo
Bassalo (Editora Livraria da Física, São Paulo, 2009), M. S. D. Cattani, L. C.
B. Crispino, M. O C. Gomes and A. F. S. Santoro (editors), pp. 31-38. Abstract: We discuss how Faraday
(1791-1867) and Maxwell (1831-1879) defined the field concept. According to
them magnetic field was a region of space close to magnetized bodies and
electric field was a region of space close to electrified bodies.
96.
A. K. T. Assis e F. M. d. M. Ravanelli, “Consequences of a generalized law of the
lever,” American Journal of Physics, Vol. 77, pp. 54-58 (2009).
Abstract: We discuss the controversy about the demonstration of the law of the
lever as given by Archimedes. One aspect of the discussion concentrates on the
meaning of the postulates which he utilized. We analyze what consequences would
arise if nature behaved in such a way that the lever followed a generalized
power law. In particular, we consider the cases of a torque independent of the
distances of the bodies to the fulcrum, proportional to these distances, and
quadratic in the distances.
95.
W. Weber, “Determinations of electrodynamic
measure: particularly in respect to the connection of the fundamental laws of
electricity with the law of gravitation,” 21st Century
Science and Technology (59 pages in PDF, posted in November, 2008: http://www.21stcenturysciencetech.com/),
English translation by G. Gregory, edited by L. Hecht and A. K. T. Assis. Contents: This is the first complete
English translation of W. Weber’s posthmous paper entitled:
Elektrodynamische Maassbestimmungen insbesondere über den Zusammenhang des
elektrischen Grundgesetzes mit dem Gravitationsgesetze. This work was originally published
in W. Weber’s Werke, Vol. IV: Galvanismus und Elektrodynamik, Part 2, edited by H. Weber (Berlin:
Julius Springer Verlag, 1894), pp. 479-525.
94.
J. A. Hernandes and A. K. T. Assis, “Surface charges
and fields in stationary conductors with steady currents,” in: B. G.
Sidharth, F. Honsell, O. Mansutti, K. Sreenivasan and A. De Angelis (editors),
Frontiers of Fundamental and Computational Physics (New York, Melville, 2008) ,
pages 236-239. Proceedings of the 9th International Symposium (
93.
J. A. Hernandes, A. J. Mania, F. R. T. Luna and A. K. T. Assis, “The internal and external electric
fields for a resistive toroidal conductor carrying a steady poloidal current,”
Physica Scripta, Vol. 78, 015403 (2008). Abstract: We consider the case of a
resistive toroidal conductor carrying a steady current in the poloidal
direction. We obtain algebraic expressions for the electric potential, the
electric field and the surface charges inside and inside the toroidal shell. We
use toroidal coordinates, in which
92.
J. E. A. Ribeiro, A. Vannucci and A. K. T. Assis, “The
multiple definitions of ‘field’ in the context of Electromagnetism,”
in: Proceedings of the VI Taller Internacional “ENFIQUI 2008”
– La Enseñanza de la Física y la Química (Universidad Pedagógica
“Juan Marinello”, Matanzas, Cuba, 8 to 12 July 2008), pp. 1-4,
ISBN: 978-959-18-0359-7, M. G. P. Batista (editor). Subject: We discuss the
several meanings which have been given to the field concept in the context of
electromagnetism.
91.
A. K. T. Assis and F. M. M. Ravanelli, “Consequences
of a quadratic law of the lever,” in: M. F. P. d. C. M. Costa, J. B.
V. Dorrío, A. C. Pavão and M. Muramatsu (editors), Proceedings of the 5th
International Conference on Hands-on Science (Espaço Ciência, Olinda-Recife,
2008), pages 82-84. This paper was also published at: International Journal on
Hands-on Science, Vol. 1, pp. 89-91 (2008). Abstract: We present the discussion
which exists in the literature related to Archimedes’s demonstration of
the law of the lever. One important aspect of the argument concentrates on the
meaning of his postulates. In order to clarify this whole subject, we analyze
what consequences would arise if nature followed a different law of the lever.
We concentrate, in particular, in the case of a torque proportional to the
square of the distances of the bodies to the fulcrum. We consider not only a
linear lever but also a horizontal triangle which can rotate around a
horizontal axis parallel to one of its sides.
90.
W. Weber, “Determinations of electrodynamic
measure: concerning a universal law of electrical action,” 21st
Century Science and Technology (146 pages in PDF, posted in March, 2007: http://www.21stcenturysciencetech.com/),
English translation by S. P. Johnson, edited by L. Hecht and A. K. T. Assis. Contents: This is the first complete
English translation of W. Weber’s paper of 1846 entitled:
Elektrodynamische Maassbestimmungen: Ueber ein allgemeines Grundgesetz der
elektrischen Wirkung. This work was originally published at the Abhandlungen
bei Begründung der Königl. Sächs. Gesellschaft der Wissenschaften am Tage der
zweihundertjährigen Geburtstagfeier Leibnizen’s herausgegeben von der
Fürstl. Jablonowskischen Gesellschaft (Leipzig), pp. 211-378 (1846). Reprinted
in W. Weber’s Werke, Vol. III: Galvanismus und Elektrodynamik, Part 1,
edited by H. Weber (Berlin: Julius Springer Verlag, 1893), pp. 25-214. In this paper Weber presented his
force depending on the relative velocity and relative acceleration between the
interacting charges. It was based upon Coulomb’s force between point
charges, Ampère’s force between current elements and Faraday’s law
of induction. In this paper Weber also presented an experimental proof of Ampère’s
force.
89. A.
K. T. Assis, “Gravitation and
cogravitation,” Annales de la Fondation Louis de Broglie, Vol. 32,
pp. 117-120 (2007). Abstract:
Review of the book Gravitation and Cogravitation: Developing Newton’s
Theory of Gravitation to Its Physical and Mathematical Conclusion, by Oleg D.
Jefimenko.
88.
A. K. T. Assis, M. P. Souza Filho, J. J. Caluzi and J. P. M. C. Chaib, “From electromagnetism to
electrodynamics: Ampère’s demonstration of the interaction between
current carrying wires,” Proceedings of the 4th
International Conference on Hands-on Science (University of Azores, Ponta
Delgada, Portugal, 2007), pp. 9-16, M. F. P. d. C. M. Costa, J. B. V. Dorrio
and R. Reis (editors). Abstract: We present Oersted’s discovery of the
torque exerted by a current carrying wire upon a nearby magnet and his
interpretation of this experiment. This opened the field of electromagnetism,
describing the interaction between current carrying wires and magnets. We
discuss Ampère’s alternative interpretation and his experiment showing a
force between a magnet and a current carrying spiral. This led him to try an
interaction between two current carrying spirals, without any magnet. He was
successful with this trial and this is one of the most important experiments in
the history of electricity. This led him to the result that current carrying
parallel wires attract (repel) one another when the currents flow along the
same direction (in opposite directions). This new field of research describing
the interaction between current carrying wires was called electrodynamics by
Ampère. We show how to perform Ampère’s crucial experiment with simple
and cheap materials.
87.
A. K. T. Assis and J. A. Hernandes, “Magnetic energy and
effective inertial mass of the conduction electrons in circuit theory,”
Electromagnetic Phenomena, Vol. 6, pp. 29-35 (2006). Abstract: In this work we
calculate the electrodynamic energy of conductors carrying slowly time-varying
currents. We show that this energy can be quantitatively identified with the
classical kinetic energy of the current-carrying electrons with effective
inertial mass proportional to the self-inductance of the conductor.
86.
J. A. Hernandes and A. K. T. Assis, “Electric potential due to an
infinite conducting cylinder with internal or external point charge,”
Journal of Electrostatics, Vol. 63, pp. 1115-1131 (2005). Abstract: We utilize
the Green’s function method in order to calculate the electric potential
due to an infinite conducting cylinder held at zero potential and a point
charge inside and outside it. We calculate and plot the net force upon the
point charge as a function of its distance to the axis of the cylinder. We show
that this force goes to zero when the radius of the cylinder goes to zero, no
matter the distance of the external point charge to the conducting line.
85.
J. A. Hernandes, E. Capelas de Oliveira and A. K. T. Assis, “Resistive plates carrying a
steady current: electric potential and surface charges close to the battery,”
Foundations of Physics Letters, Vol. 18, pp. 275-289 (2005). Abstract: We treat
the problem of two resistive plates carrying a steady current in the same
direction. We consider a linear battery orthogonal to the direction of the
current in the middle of the plates. We study the behavior of the surface
charges close to the battery. We also consider the case of a single resistive
plate carrying a steady current.
84.
J. A. Hernandes and A. K. T. Assis, “The electric field outside and
inside a resistive spherical shell carrying a steady azimuthal current,”
Physica Scripta, Vol. 72, pp. 212-217 (2005). Abstract: We calculate the
potential, electric field and surface charges outside and inside a resistive spherical
shell carrying a steady azimuthal current. We obtain a time-independent
electric field different from zero in both regions.
83.
A. K. T. Assis and J. A. Hernandes, “Telegraphy equation
from Weber’s electrodynamics,” IEEE Transactions on Circuits
and Systems II, Vol. 52, pp. 289-292 (2005), Abstract: We derive the telegraphy
equation according to Weber’s electrodynamics for signal propagating
along a very long bidimensional wire in the shape of a rectangular strip of
zero thickness. We also derive this equation of a twin lead composed of two of
these parallel very long bidimensional wires facing each other. We compare this
result with classical electromagnetism.
82.
A. K. T. Assis, “Weber’s electrodynamics and Mach’s
principle in the 21st century,” in: Vom Magnetismus zur
Elektrodynamik, G. Wolfschmidt (editor), (Schwerpunkt Geschichte der
Naturwissenschaften, Mathematik und Technik;
81.
R. S. Mendes, L. C. Malacarne and A. K. T. Assis, “Virial theorem for Weber’s law,” in:
Has the Last Word Been Said on Classical Electrodynamics? New Horizons, A.
Chubykalo, A. Espinoza, V. Onoochin and R. Smirnov-Rueda (editors), (Rinton
Press,
80.
A. K. T. Assis, K. Reich and K. H. Wiederkehr, “On the electromagnetic and
electrostatic units of current and the meaning of the absolute system of units
– For the 200th anniversary of Wilhelm Weber’s birth,”
Sudhoffs Archiv, Vol. 88 (1), pp. 10-31 (2004). Abstract: We present the
development of the absolute system of units concentrating on the fundamental
works of C. F. Gauss and W. Weber. A greater emphasis is given to the different
units of electric current due to their central role in this development.
79.
J. A. Hernandes and A. K. T. Assis, “Surface charges and
external electric field in a toroid carrying a steady current,”
Brazilian Journal of Physics, Vol. 34, pp. 1738-1744 (2004). Abstract: We solve
the problem of a resistive toroid carrying a steady azimuthal current. We use
standard toroidal coordinates, in which case
78. A.
K. T. Assis, “The principle of physical proportions,” Annales de la Fondation Louis de
Broglie, Vol. 29, pp. 149-171 (2004). Abstract: We propose the principle of physical proportions, according to
which all laws of physics can depend only on the ratio of known quantities of
the same type. An alternative formulation is that no dimensional constants
should appear in the laws of physics; or that all “constants” of
physics (like the universal constant of gravitation, light velocity in vacuum,
Planck’s constant, Boltzmann’s constant etc.) must depend on
cosmological or microscopic properties of the universe. With this
generalization of Mach’s principle we advocate doing away with all
absolute quantities in physics. We present examples of laws satisfying this
principle and of others which do not. These last examples suggest that the
connected theories leading to these laws must be incomplete. We present
applications of this principle in some fundamental equations of physics.
77.
J. A. Hernandes, E. Capelas de Oliveira and A. K. T. Assis, “Potential,
electric field and surface charges close to the battery for a resistive
cylindrical Shell carrying a steady longitudinal current,” Revista de
la Facultad de Ingenieria (Chile), Vol. 12, pp. 13-20 (2004). Abstract: In this
work we consider a long, resistive cylindrical shell carrying a steady current.
A battery in the middle of the wire generates the current. We study the behavior
of the potential, electric field and surface charges close to the battery.
76. A.
K. T. Assis and K. H. Wiederkehr, “Weber quoting
Maxwell,” Mitteilungen der Gauss-Gesellschaft, Vol. 40, pp. 53-74
(2003). Abstract: This
article deals with the supersession of Wilhelm Weber’s and Franz
Neumann’s older theory of electrodynamics by Maxwell’s theory in
the last third of the 19th century. Starting-point and basis for the
presentation are the few quotations that can be found in Weber’s works.
The discussion was mainly performed by Carl von Neumann and Johann Karl
Friedrich Zöllner. Both were engaged supporters and advocates of Weber’s
view of electricity. Points of controversy were: (1) The theory of close-range
effects, which is identical to Maxwell’s concept of field and which stood
in contrast to distant range theory (prototype: Newton’s gravitational
law), and (2) the assumption of the existence of an electrical substance. Weber
persisted right to the end in his concept and developed an atomic model that
can be regarded as an initial stage of the Rutherford-Bohr atomic model.
Consensus existed in the absolute electrical measurement systems. J. Cl. Maxwell
inferred the velocity of light from the Kohlrausch-Weber-experiment.
Weber’s absolute electro-magnetic system served as a basis for the
international units of measure in 1881.
75.
J. A. Hernandes and A. K. T. Assis, “Electric potential for a resistive
toroidal conductor carrying a steady azimuthal current,” Physical
Review E, Vol. 68, 046611 (2003). Abstract: In this work we treat a resistive
toroidal conductor carrying a steady azimuthal current. We calculate the
electric potential everywhere in space. We also present the electric field
inside and outside the toroid and the surface charges distribution along the
conductor. We compare our theoretical result with Jefimenko’s experiment.
74.
J. Fukai and A. K. T. Assis, “Testing Mach’s principle in
electrodynamics,” Canadian Journal of Physics, Vol. 81, pp. 1239-1242
(2003). Abstract: We analyze the consequences of Mach’s principle as
applied to electromagnetism. This view reveals new effects not predicted by
standard electromagnetic theory.
73.
J. A. Hernades and A. K. T. Assis, “The potential, electric field and
surface charges for a resistive long straight strip carrying a steady current,”
American Journal of Physics, Vol. 71, pp. 938-942 (2003). Abstract: We consider
a long resistive straight strip carrying a constant current and calculate the
potential and electric field everywhere in space and the density of surface
charges along the strip. We compare these calculations with experimental
results.
72.
A. K. T. Assis, “On the first
electromagnetic measurement of the velocity of light by Wilhelm Weber and
Rudolf Kohlrausch,” in Volta and the History of Electricity, edited
by F. Bevilacqua and E. A. Giannetto (Università degli Studi di Pavia and
Editore Ulrico Hoepli, Milano, 2003), pp. 267-286. Abstract: The electrostatic,
electrodynamic and electromagnetic systems of units utilized during last
century by Ampère, Gauss, Weber, Maxwell and all the others are analyzed. It is
shown how the constant c was introduced
in physics by Weber’s force of 1846. It is shown that it has the
unit of velocity and is the ratio of the electromagnetic and electrostatic
units of charge. Weber and Kohlrausch’s experiment of 1855 to determine c
is quoted, emphasizing that they were the first to measure this quantity and
obtained the same value as that of light velocity in vacuum. It is shown how
Kirchhoff in 1857 and Weber (1857-64) independently of one another obtained the
fact that an electromagnetic signal propagates at light velocity along a thin
wire of negligible resistivity. They obtained the telegraphy equation utilizing
Weber’s action at a distance force. This was accomplished before the
development of Maxwell’s electromagnetic theory of light and before
Heaviside’s work. As an Appendix of this paper there is a complete
English translation of the paper by W. Weber and R. Kohlrausch, Ueber die
Elektricitätsmenge, welche bei galvanischen Strömen durch den Querschnitt der
Kette fliesst, Annalen der Physik, Vol. 99, pp. 10-25 (1856): W. Weber and R.
Kohlrausch, On the amount of electricity which flows through the cross-section
of the circuit in galvanic currents, translated by S. P. Johnson and edited by
L. Hecht, in Volta and the History of Electricity, edited by F. Bevilacqua and
E. A. Giannetto (Università degli Studi di Pavia and Editore Ulrico Hoepli,
Milano, 2003), pp. 287-297.
71. A.
K. T. Assis and J. Guala-Valverde, "Frequency in relational mechanics," Annales de la Fondation Louis de
Broglie, Vol. 28, pp. 83-97 (2003). Abstract: We analyze the dependence of the frequency of oscillation of
several macroscopic motions as regards the density of distant gravitational
matter according to relational mechanics. We conclude that in most situations
the frequency is inversely proportional to the square root of this density.
70.
A. K. T. Assis, “The
relationship between Mach's principle and the principle of physical proportions,”
In: Mach's Principle and the Origin of Inertia, M. Sachs and A. R. Roy
(Editors), (Apeiron,
69.
A. K. T. Assis, K. Reich and K. H. Wiederkehr, “Gauss and Weber's creation of the
absolute system of units in physics,” 21st Century, Vol. 15, No. 3,
pp. 40-48 (2002). Contents: It is presented the absolute system of units
created by Gauss and Weber. It is discussed Gauss's seminal paper of 1832, the
intensity of the earth's magnetic force reduced to absolute measurement, and
his solution of this problem. The joint work of Gauss and Weber is analyzed and
also their creation of the magnetic association.
68.
A. K. T. Assis and J. Guala-Valverde, “On absolute and relative motions in
physics,” Journal of New Energy, Vol. 6, No. 4, pp. 8-12 (2002).
Abstract: The authors present the Newtonian definitions of absolute and
relative motion. The idea is defended that only relative motions of matter
relative to matter can be detect and lead to measurable effects. Phenomena is
analyzed depending on velocity and acceleration in electromagnetism and
mechanics.
67.
A. K. T. Assis and J. A. Hernandes, “Electric potential for a toroidal ring
carrying a constant current,” Proceedings of the XXIII Encontro
Nacional de Física de Partículas e Campos (15 to 19/10/2002, Águas de Lindóia,
Brazil), P-115. Abstract: In this work we treat a conducting toroidal ring
carrying a constant current. We calculate the electric potential everywhere in
space. We compare our theoretical result with Jefimenko's experiment.
66.
J. A. Hernandes and A. K. T. Assis, “Potential, electric field and surface
charges for a resistive long straight strip carrying a constant current,”
Proceedings of the XXIII Encontro Nacional de Física de Partículas e Campos (15
to 19/10/2002, Águas de Lindóia, Brazil), P-163. Abstract: We consider a long
resistive straight strip carrying a constant current. We calculate the potential
and electric field everywhere in space and also the density of surface charges
along the strip. We compare the calculations with experimental results.
65.
A. K. T. Assis, "On the unification
of forces of nature," Annales de la Fondation Louis de Broglie, Vol.
27, pp. 149-161 (2002). Abstract: Different aspects of physical interaction are
considered: inertia, gravitation, electrostatics, magnetostatics and galvanism.
It is discussed the experimental and theoretical reasons leading to the
unification of some of them. It is then explored by analogies what might lead
to the unification of gravitation with electromagnetism.
64.
H. Torres S. and A. K. T. Assis, “The influence of
the electric field outside a resistive solenoid on the Aharonov-Bohm effect,”
Revista de la Facultad de Ingenieria de la Universidad de Tarapaca (Chile),
Vol. 9, pp. 29-34 (2001). Abstract: It is a known fact that there is no
magnetic field outside an infinite solenoid carrying a constant current,
although there is a magnetic vector potential non-null outside it. The
existence of the Aharonov-Bohm effect (AB) is usually considered as a proof of
the relevance of the vector potential for quantum mechanics. In this paper we
will see that there is a non null electric field outside an infinite solenoid
carrying a constant current and its possible relevance to the analysis of the
Aharonov-Bohm effect. When calculating, we introduce the Galilean invariance of
Maxwell's equations and then we obtain the contribution to the AB effect due to
electric potential.
63.
A. K. T. Assis, J. A. Hernandes and J. E. Lamesa, “Surface charges in conductor plates
carrying constant currents,” Foundations of Physics, Vol. 31, pp.
1501-1511 (2001). Abstract: In this work we analyze the case of resistive
conductor plates carrying constant currents, utilizing surface charge
distributions. We obtain the electric potential in the plates and in the space
surrounding them. We obtain a non-vanishing electric field outside the
conductors. We compare the theoretical results with experimental data present
in the literature.
62.
A. K. T. Assis, “Applications of the
principle of physical proportions to gravitation,” In: Gravitation,
Electromagnetism and Cosmology - Toward a New Synthesis, K. Rudnicki (editor),
(Apeiron,
61.
A. K. T. Assis and A. Zylbersztajn, “The influence of Ernst Mach in
the teaching of mechanics,” Science and Education, Vol. 10, pp.
137-144 (2001). Abstract: We present
60.
A. K. T. Assis, Comment on
"Experimental proof of standard electrodynamics by measuring the
self-force on a part of a current loop", Physical Review E, Vol. 62,
p. 7544 (2000). Abstract: We discuss the paper of Cavalleri et al. [Phys. Rev.
E 58, 2505 (1998)] on the measurement of a force on part of a closed circuit
carrying a constant current.
59.
A. K. T. Assis, J. Fukai and H. B. Carvalho, “Weberian induction,”
Physics Letters A, Vol. 268, pp. 274-278 (2000). Abstract: Various kinds of
electric polarization of a rotating metallic disc are discussed. A new kind of
induction is predicted by Weber's electrodynamics, but not by Maxwellian
electrodynamics. An experiment test to check this new effect is proposed.
58.
A. K. T. Assis and J. I. Cisneros, “Surface charges and
fields in a resistive coaxial cable carrying a constant current,”
IEEE Transactions on Circuits and Systems I, Vol. 47, pp. 63-66 (2000),
Abstract: We calculate the surface charges, potentials, and fields in a long
cylindrical coaxial cable with inner and outer conductors of finite
conductivities and finite areas carrying a constant current. It is shown that
there is an electric field outside the return conductor.
57.
A. K. T. Assis, “On the
propagation of electromagnetic signals in wires and coaxial cables according to
Weber's electrodynamics,” Foundations of Physics, Vol. 30, pp.
1107-1121 (2000). Abstract: We derive the equation describing the flow of a
variable current in straight wires and in coaxial cables from
56.
A. K. T. Assis, “The
meaning of the constant c in Weber's electrodynamics,” In: Proceeding
of the International Conference Galileo Back in Italy II, R. Monti (editor),
(Societá Editrice Andromeda,
55.
A. K. T. Assis and H. Torres Silva, “Comparison between Weber's
electrodynamics and classical electrodynamics,” Pramana Journal of
Physics, Vol. 55, pp. 393-404 (2000). Abstract: We present the main aspects of
Weber's electrodynamics and of Maxwell's equations. We discuss Maxwell's point
of view related to Weber's electrodynamics. We compare Weber's force with
Lorentz's force. We analyse the relation between Weber's law and Maxwell's
equation. Finally, we discuss some experiments performed and proposed with
which we can distinguish Weber's force from Lorentz's one.
54.
A. K. T. Assis and J. Guala-Valverde, “Mass in relational mechanics,”
Apeiron, Vol. 7, pp. 131-132 (2000). Abstract: We clarify a misunderstanding
that appeared in the literature.
53. A. K. T. Assis and Marcelo Bueno, “Bootstrap effect in classical
electrodynamics,” Revista Facultad de Ingenieria de la
Universidad de Tarapaca (Chile), Vol. 7, pp. 49-55 (2000). Abstract: We calculate the force on part of a
circuit due to the remaining circuit using Ampère's force and Grassmann's
force. Using a symmetrical configuration we perform the calculations using
linear current elements. We show that both expressions give the same result.
Then we present some general arguments to show that even with Grassmann's force
a single closed circuit of arbitrary form cannot exert a net force on itself.
Moreover, we show that the force acting on any straight conductor belonging to
a closed circuit of arbitrary form, due to the remaining of this circuit, is
orthogonal to this conductor and has the same value according to Ampère's force
and to Grassmann's force.
52.
A. K. T. Assis, W. A. Rodrigues Jr. and A. J. Mania, “The electric field outside a
stationary resistive wire carrying a constant current,” Foundations
of Physics, Vol. 29, pp. 729-753 (1999). Abstract: We present the opinion of
some authors who believe there is no force between a stationary charge and a
stationary resistive wire carrying a constant current. We show that this force
is different from zero and present its main components: the force due to the
charges induced in the wire by the test charge and a force proportional to the
current in the resistive wire. We also discuss briefly a component of the force
proportional to the square of the current which should exist according to some
models and another component due to the acceleration of the conduction
electrons in a curved wire carrying a dc current (centripetal acceleration).
Finally, we analyse experiments showing the existence of the electric field
proportional to the current in resistive wires.
51.
A. K. T. Assis, “Arguments
in favour of action at a distance,” In: Instantaneous Action at a
Distance - Pro and Contra, edited by A. E. Chubykalo, V. Pope and R. Smirnov-Rueda
(Nova Science Publishers, Commack, 1999), pp. 45-56. Abstract: Several
arguments favouring instantaneous action at a distance are presented. The
action at a distance laws of
50.
A. K. T. Assis and J. J. Caluzi, “Charged particle oscillating
near a capacitor,” Galilean Electrodynamics, Vol. 10, pp. 103-106
(1999). Abstract: We study the oscillation of a charged particle near a
capacitor in four different models: Classical mechanics, Weber's
electrodynamics plus classical mechanics, relativistic mechanics, and Weber's
electrodynamics plus the mechanics of Erwin Schrodinger. We show that only the
third and fourth models yield a physically reasonable results.
49.
A. K. T. Assis and A. J. Mania, “Surface charges and electric
field in a two-wire resistive transmission line,” Revista Brasileira
de Ensino de Física, Vol. 21, pp. 469-475 (1999). Abstract: We consider a
two-wire resistive transmission line carrying a constant current. We calculate
the potential and electric field outside the wires showing that they are
different from zero even for stationary wires carrying dc currents. We also
calculate the surface charges giving rise to these fields and compare the
magnetic force between the wires with the electric force between them. Finally
we compare our calculations with Jefimenko's experiment.
48.
A. K. T. Assis and J. I. Cisneros, “The
problem of surface charges and fields in coaxial cables and its importance for
relativistic physics,” In: Open Questions in Relativistic Physics, F.
Selleri (editor), (Apeiron, Montreal, 1998), pp. 177-185. Abstract: We
calculate the surface charges, potentials and fields in a long cylindrical
coaxial cable with inner and outer conductors of finite conductivities and
finite areas. It is shown that there is an electric field outside the return
conductor.
47.
M. A. Bueno and A. K. T. Assis, “Deriving force from
inductance,” IEEE Transactions on Magnetics, Vol. 34, pp. 317-319
(1998). Abstract: The correctness of calculating the force on current carrying
circuits by taking the derivative of the inductance coefficient of the circuits
is shown even in the case of a single closed circuit, contrary to the opinion
of some authors. This demonstration is illustrated with the force exerted by a
cylinder with poloidal current on an infinitesimal strip belonging to the same
cylinder. The force is calculated directly from the force expressions and also
by differentiating the self-inductance of the cylinder. This result is another
proof of the equivalence between Ampère and Grassmann's forces.
46.
Marcelo Bueno and A. K. T. Assis, “Equivalence between the formulas for
inductance calculation,” Canadian Journal of Physics, Vol. 75, pp.
357-362 (1997). Abstract: We demonstrate the equivalence for the
self-inductance of closed circuits, with the formulas of Neumann, Weber,
Maxwell, and Graneau.
45.
J. J. Caluzi and A. K. T. Assis, “A critical analysis of
Helmholtz’s argument against Weber’s electrodynamics,”
Foundations of Physics, Vol. 27, pp. 1445-1452 (1997). Abstract: We present
Helmholtz's argument against Weber's electrodynamics. It is related with a
fixed charged nonconducting spherical shell and a charged particle moving
inside it. Then we utilize Weber's electrodynamics plus Schrödinger's
expression for gravitational interactions in order to obtain the equation of
motion and to study this situation. We show that this approach avoids the
problems pointed out by Helmholtz. Moreover, it indicates that the effective
inertial mass of the charged particle will depend not only on the electrostatic
potential of the shell but also on its velocity. This is a relevant aspect of
Weber's theory.
44.
Marcelo Bueno and A. K. T. Assis, “Self-inductance of solenoids,
bi-dimensional rings and coaxial cables,” Helvetica Physica Acta,
Vol. 70, pp. 813-821 (1997). Abstract: We compare the self-inductance formulae
of Neumann, Weber, Maxwell and Graneau. To this end we present exact and
algebraic formulae for the self-inductance of solenoids, bi-dimensional rings
and coaxial cables. We show that these four formulas agree exactly with one
another for closed circuits.
43.
Marcelo Bueno and A. K. T. Assis, “Proof of the identity between
Ampère and Grassmann’s forces,” Physica Scripta, Vol. 56, pp. 554-559
(1997). Abstract: We consider a poloidal current flowing over the surface of a
conducting cylinder of length l and radius a. We calculate exactly the force on
a surface current element belonging to this cylinder due to the remainder of
the circuit with Ampère and Grassmann's expressions. We conclude that the
formulae agree with one another for any value of l/a. We then generalize this
result for any current element belonging to a closed surface or volumetric
currents of arbitrary forms.
42.
A. K. T. Assis, “Circuit
theory in Weber electrodynamics,” European Journal of Physics, Vol.
18, pp. 241-246 (1997). Abstract: We present a derivation of the equation
describing the current flow in a circuit with self-inductance based on
41.
A. K. T. Assis and Marcelo A. Bueno, “Equivalence between Ampère
and Grassmann's forces,” IEEE Transactions on Magnetics, Vol. 32, pp.
431-436 (1996). Abstract: We calculate the force on part of a single closed
circuit due to the remaining circuit in four different geometries according to
the forces of Ampère and Grassmann. All analytical calculations are performed
using surface or volume current elements in order to avoid the divergences
which appear with linear current elements of zero diameter. We conclude that
when we consider the action of a closed circuit as a whole and utilize only
circuits with closed lines of current, there will be an equivalence between the
expressions of Grassmann and Ampère. This means that both of them are
compatible with the experimental findings related to Ampère's bridge, contrary
to the opinion of some authors.
40.
J. J. Caluzi and A. K. T. Assis, “The oscillatory motion of charged
particles by Weber’s electrodynamics,” In: New Frontiers in
Physics, Vol. I, T. P. Gill (ed.), (Hadronic Press, Palm Harbor, 1996), pp.
129-143. Abstract: We analyse the oscillatory motion of a charged particle
outside an ideal capacitor by four different models: classical, relativistic,
Weber's electrodynamics and Weber's electrodynamics plus Schrödinger's
mechanics. These two last models yield a period of oscillation depending on the
voltage of the capacitor.
39.
A. K. T. Assis and P. Graneau, “Nonlocal forces of inertia in
cosmology,” Foundations of Physics, Vol. 26, pp. 271-283 (1996).
Abstract: This paper reviews the origin of inertia according to Mach's
principle and Weber's law of gravitation. The resulting theory is based on
simultaneous nonlocal gravitational interactions between particles in the solar
system and others in the remote universe beyond the Milky Way galaxy. It
explains the precession of the perihelion of Mercury. A most important
implication of the Mach-Weber theory of the force of inertia is the necessity
of a large amount of uniformly distributed matter in the galactic universe.
This matter could be the source of the cosmic background radiation. Nonlocal
inertia forces are compatible with a static universe and also with an expanding
universe but the latter would demand slow changes in the mass of particles and
the gravitational constant.
38.
A. K. T. Assis and Marcelo Bueno, “Longitudinal forces in
Weber's electrodynamics,” International Journal of Modern Physics B,
Vol. 9, pp. 3689-3696 (1995). Abstract: We analyze the existence of
longitudinal forces with Weber's electrodynamics. We show that they exist. But
they cannot explain the exploding wire phenomena due to their order of
magnitude.
37.
J. J. Caluzi and A. K. T. Assis, “An analysis of Phipps's
potential energy,” Journal of the Franklin Institute, Vol.
332B, pp. 747-753 (1995). Abstract: We discuss a modification of Weber's law
proposed by T. E. Phipps. We calculate the energy and force on a charge moving
inside and outside a capacitor according to Phipp's modification of Weber's
electrodynamics. When Phipps postulated his potential energy he answered
Helmholtz's criticism of Weber's law (the negative mass behaviour). But when we
utilize Phipps's potential energy together with the classical kinetic energy
this leads to an unphysical result.
36.
A. K. T. Assis, “Gravitation
as a fourth order electromagnetic effect,” In: Advanced
Electromagnetism: Foundations, Theory and Applications, T. W. Barrett and D. M.
Grimes (eds.), (World Scientific, Singapore, 1995), pp. 314-331. Abstract: We
present a generalized Weber's law for electromagnetism including terms of
fourth and higher orders in 1/c. These extra terms when applied to the force
between two neutral dipoles yield an equivalent to
35.
Marcelo A. Bueno and A. K. T. Assis, "A new method of inductance
calculations," Journal of Physics D, Vol. 28, pp. 1802-1806 (1995).
Abstract: A new method for calculating inductances is presented. The method
results in analytically simple expressions that replace the traditional tables
and working formulae. Moreover, it overcomes the diverging self-inductances of
thin wires.
34.
M. C. D. Neves and A. K. T. Assis, “The Compton effect as an
explanation for the cosmological redshift,” Quarterly Journal of the
Royal Astronomical Society, Vol. 36, pp. 279-280 (1995). Subject: We discuss if
the Compton effect is or not a reasonable explanation for the cosmological
redshift yielding Hubble's law.
33.
A. K. T. Assis, “Weber's
force versus Lorentz's force,” Physics Essays, Vol. 8, pp. 335-341
(1995). Abstract: We make a comparison between Weber's force and Lorentz's
force. First, we present the historical appearance of these two forces. Then we
show their theoretical and conceptual differences. After this we discuss some
different predictions of experiments with these two expressions showing how
they can be distinguished in the laboratory.
32.
A. K. T. Assis and M. C. D. Neves, “The redshift revisited,”
Astrophysics and Space Science, Vol. 227, pp. 13-24 (1995). This paper was also
published in: Plasma Astrophysics and Cosmology, A. L. Peratt (ed.), (Kluwer
Academic Publishers, Dordrecht, 1995), pp. 13-24. Abstract: We analyse the history
of modern comsmology based on the redshift phenomenon and on the cosmic
background radiation (CBR). We show the models of different authors for the
interpretation of the redshift and how the tired light models predicted the
correct value of 2.7K temperature previous to Gamow and collaborators.
31.
A. K. T. Assis, “Weber's
law and Mach's principle,” In: Mach's Principle: From Newton's Bucket
to Quantum Gravity, H. Pfister and J. B. Barbour (eds.), (Birkhäuser, Boston,
1995), pp. 159-171. Subject: We discuss the implementation of Mach's principle
based on Weber's law applied to gravitation.
30.
A. K. T. Assis, “Acceleration
dependent forces: reply to Smulsky,” Apeiron, Vol. 2, p. 25 (1995).
Subject: We discuss forces which depend on the acceleration of the test charge.
29.
A. K. T. Assis and P. Graneau, “The reality of Newtonian forces of
inertia,” Hadronic Journal, Vol. 18, pp. 271-289 (1995). Abstract: We
present a historical analysis of the inertial forces and of the theories
developed to explain the origin of inertia. Then we introduce the principle of
dynamical equilibrium and its relevance to mechanics. We analyse the Mach-Weber
model which implements Mach's principle with Newtonian simultaneous
interactions and we argue for the reality of the inertial forces, that is: the
force of free fall (-ma), the centrifugal force and the Coriolis force. Lastly
we present an experimental consequence of the Mach-Weber model which differs
from
28.
A. K. T. Assis and M. C. D. Neves, “History
of the 2.7 K temperature prior to Penzias and Wilson,” Apeiron, Vol.
2, pp. 79-84 (1995). Abstract: We present the history of estimates of the
temperature of intergalactic space. We begin with the works of Guillaume and
Eddington on the temperature of interstellar space due to starlight belonging
to our Milky Way galaxy. Then we discuss works relating to cosmic radiation,
concentrating on Regener and Nernst. We also discuss Finlay-Freunlich's and Max
Born's important research on this topic. Finally, we present the work of Gamow
and collaborators. We show that the models based on a universe in dynamical
equilibrium without expansion predicted the 2.7K temperature prior to and
better than the models based on the big bang.
There are two Appendices to this paper. One is a complete English
translation of
27.
J. J. Caluzi and A. K. T. Assis, “Schrödinger's potential energy and
Weber's electrodynamics,” General Relativity and Gravitation,
Vol. 27, pp. 429-437 (1995). Abstract: We discuss Schrödinger's approach
to gravitational interactions and Weber's electrodynamics. Then we make use of
this model to calculate the energy of a charge moving inside and outside an
ideal capacitor. This results in an ultimate speed, c, and in the variation of
the mass of the particle with the electrostatic potential and its velocity.
26.
P. Graneau and A. K. T. Assis, “Kirchhoff
on the motion of electricity in conductors,” Apeiron, Vol. 19, pp.
19-25 (1994). Abstract: We comment on and translate Gustav Kirchhoff's important
paper of 1857 entitled "On the motion of electricity in conductors."
The significance of this paper is that Kirchhoff proved with action at a
distance that electric disturbances travel along wires of negligible resistance
with the velocity of light. He accomplished this with the laws of Newtonian
electrodynamics (Coulomb, Ampere, F. Neumann and Weber) before Maxwell had
formulated his equations.
25.
A. K. T. Assis and D. S. Thober, “Unipolar induction and
Weber's electrodynamics,” In: Frontiers of Fundamental Physics, M.
Barone and F. Selleri (eds.), (Plenum Press, New York, 1994), pp. 409-414.
Subject: We discuss unipolar induction and how it can be interpreted based on
Weber's electrodynamics. We present predictions of the results of new
experiments based on Weber's law.
24.
A. K. T. Assis and R. A. Clemente, “The influence of temperature on
gravitation,” Nuovo Cimento B, Vol. 108, pp. 713-716 (1993).
Abstract: We present some general reasonings using the mass-energy equivalence
and Weber's force law for gravitation to show that the weight of a body should
increase with its temperature. The two approaches predict a fractional change of
weight or, equivalently, of the gravitational constant G, of one part in
10^{14} per degree.
23.
A. K. T. Assis, “Compliance of a
Weber's force law for gravitation with Mach's principle,” In: Space
and Time Problems in Modern Natural Sciences, Part II, P. N. Kropotkin et al.
(editors), (Tomsk Scientific Center of the Russian Academy of Sciences,
St.-Petersburg, 1993), pp. 263-270. Abstract: We discuss the different aspects
and meanings of Mach's principle and present the consequences a dynamic model
should lead in order to incorporate this principle. Then we analyse a Weber
force law for gravitation from this point of view and conclude that it seems to
be in full compliance with Mach's principle.
22.
A. K. T. Assis, “A
steady-state cosmology,” In: Progress in New Cosmologies: Beyond the
Big Bang, H. C. Arp, C. R. Keys and K. Rudnicki (editors), (Plenum Press, New
York, 1993), pp. 153-167. Abstract: We analyze a steady-state cosmology based
on a boundless universe which has always existed and which is homogeneous on
the very large scale. As this is a stationary model without expansion, it does
not require a continous creation of matter, in contrast to the steady-state
model of Bondi, Hoyle and Gold. We study the problems and properties of this
model relating to inertia and gravitation (Mach's principle and the origin of
inertia, the Seeliger-Neumann term), the cosmological redshift (alternatives to
the Doppler interpretation of Hubble's law, the Finlay-Freundlich model), and
the cosmic background radiation (predictions of a background temperature around
3K previous to the experimental discovery by Penzias and Wilson in 1965). Some
observational tests of this general model are outlined.
21.
A. K. T. Assis, “Changing
the inertial mass of a charged particle,” Journal of the Physical
Society of Japan, Vol. 62, pp. 1418-1422 (1993). Abstract: We calculate utilizing
Weber's law the force on a moving charge exerted by a stationary charged
spherical shell surrounding it. We obtain a net force different from zero which
is proportional to the acceleration of the test particle relative to the
spherical shell. This result can be interpreted by saying that the inertial
mass of a test particle should change if it is placed inside a charged
spherical shell. We conclude that this modification in the inertial mass is
proportional to the electrostatic potential of the charged spherical shell and
to the electric charge of the test particle. Then we present some possible
experiments which could be performed to test this prediction.
20.
A. K. T. Assis, “Deriving
gravitation from electromagnetism,” Canadian Journal of Physics, Vol.
70, pp. 330-340 (1992). Abstract: We present a generalized Weber force law for
electromagnetism including terms of fourth and higher orders in v/c. We show
that these extra terms yield an attractive force between two neutral dipoles in
which the negative charges oscillate around the positions of equilibrium. This
attractive force can be interpreted as the usual Newtonian gravitational force
as it is of the correct order of magnitude, is along the line joining the
dipoles, follows
19.
A. K. T. Assis and R. A. Clemente, “The ultimate speed implied by
theories of Weber's type,” International Journal of Theoretical
Physics, Vol. 31, pp. 1063-1073 (1992). Abstract: As in the last few years
there has been a renewed interest in the laws of Ampère for the force between
current elements and of Weber for the force between charges, we analyze the
limiting velocity which appears in Weber's law. Then we make the same analysis
for Phipps' potential and for generalizations of it. Comparing the results with
the relativistic calculation, we obtain that these theories can yield c for the
ultimate speed of charges or for the ultimate relative speed between the
charges but not for both simultaneously, as is the case in the special theory
of relativity.
18.
A. K. T. Assis, “On forces
that depend on the acceleration of the test body,” Physics Essays,
Vol. 5, pp. 328-330 (1992). Abstract: We discuss Waldron's arguments against
force laws that depend on the acceleration of the test body and show that they
are incorrect. In contrast to Waldron's point of view, we show that these force
laws are compatible with
17.
A. K. T. Assis, “Cosmic background
radiation: reply to Shlenov,” Apeiron, Vol. 13, p. 24 (1992).
Subject: We discuss the cosmic background radiation.
16.
A. K. T. Assis and F. M. Peixoto, “On the velocity in the Lorentz force
law,” The Physics Teacher, Vol. 30, pp. 480-483 (1992). Subject: We
discuss the historical origins of the magnetic force in the works of J. J.
Thomson, O. Heaviside and H. A. Lorentz. We discuss the different meanings
which have been employed historically to the velocity of the test charge which
appears in this expression.
15.
A. K. T. Assis, “On the absorption
of gravity,” Apeiron, Vol. 13, pp. 3-11 (1992). Abstract: We proposed
a modified Weber's potential for gravitation that takes into account the
influence of intervening matter. Then we obtain equations of motion similar to
14.
A. K. T. Assis, “On the
mechanism of railguns,” Galilean Electrodynamics, Vol. 3, pp. 93-95
(1992). Abstract: Two mechanisms utilized to explain the operation of railguns
are explained: one based on Ampère's force and the other on the transfer of
momentum through electromagnetic waves. It is shown how the former is
compatible with the data while the latter has problems with the quantitative
figures and the case of the immobilized projectile.
13.
A. K. T. Assis, “On Hubble's law
of redshifts, Olbers' paradox and the cosmic background radiation,”
Apeiron, Vol. 12, pp. 10-16 (1992). Abstract: We utilize the principle of
conservation of energy in a model which explains the cosmological redshift,
Olbers' paradox and the cosmic background radiation. The model is based on a
hypothesis of absorption and emission of light by galactic and intergalactic
matter, and a mean temperature of matter in the universe compatible with the
background radiation. We also discuss the early works of Regener and Nernst
related to these topics. Lastly we derive some known scaling laws for galaxies,
i.e., luminosity to mass and luminosity to area, which had not been well
understood up to now. All of this is accomplished supposing a boundless, stationary
universe that is homogeneous on the large scale.
12.
A. K. T. Assis, “Centrifugal
electrical force,” Communications in Theoretical Physics, Vol. 18,
pp. 475-478 (1992). Abstract: We calculate the force on a point charge moving
within a charged spherical shell spinning with w(t) according to Weber's law.
We compare this result with the one given by Lorentz's law and show that
Weber's law predicts an extra centrifugal electrical force and an extra
inertial electrical force. We give orders of magnitude for these forces and
propose some experiments to test the existence of these terms.
11.
R. A. Clemente and A. K. T. Assis, “Two-body problem for Weber-like
interactions,” International Journal of Theoretical Physics, Vol. 30,
pp. 537-545 (1991). Abstract: The problem of two moving bodies interacting
through a Weber-like force is presented. Trajectories are obtained analytically
once relativistic and quantic considerations are neglected. The main results
are that in the case of limited trajectories, in general, they are not closed
and in the case of open trajectories, the deflection angles are not the same
for similar particles with given energies and angular momenta but opposite
potentials. This last feature suggests the possibility of a direct verification
of the validity of Weber's law of force for electromagnetic interactions.
10.
A. K. T. Assis, “Perplex numbers and
quaternions,” International Journal of Mathematical Education in
Science and Technology, Vol. 22, pp. 555-562 (1991). Abstract: We present some
properties of mathematical and physical interest in generalized algebras of
two, three and four dimensions. We give a new formulation for these algebras,
stress some important applications related to the wave equation, and emphasize
a novel didactic approach to this subject.
9.
A. K. T. Assis, “Can a steady
current generate an electric field?” Physics Essays, Vol. 4, pp.
109-114 (1991). Abstract: We present the results for the electric and magnetic
fields due to linear and circular current distributions according to Weber's theory.
We show how the electric field predicted by Weber's law is compatible with the
anomalous diffusion in plasmas. Finally, we discuss some modern experiments
related to this topic and compare the results of these experiments with a
prediction based on Weber's law.
8.
A. K. T. Assis and J. J. Caluzi, “A limitation of Weber's law,”
Physics Letters A, Vol. 160, pp. 25-30 (1991). Abstract: We present Weber's law
and its main properties. We discuss its relation with the experiments of mass
variation with velocity. Then we calculate the energy and force on a charge
moving inside and outside a capacitor according to Weber's electrodynamics. We
discuss the consequences of this relation, and in particular we show that in
this model a charge could attain velocities larger than the light velocity in a
limited space due to a finite and feasible voltage difference. As this has
never been observed we conclude that Weber's electrodynamics should not be
applied to charges moving near the light velocity.
7.
A. K. T. Assis, “Modern
experiments related to Weber's electrodynamics,” In: Proceedings of
the Conference on Foundations of Mathematics and Physics, U. Bartocci and J. P.
Wesley (editors), (Benjamin Wesley Publisher, Blumberg, Germany, 1990), pp.
8-22. Abstract: We present Weber's force law and the classical results that
follow from it. We discuss the historical controversy surrounding Ampère's law
of force between current elements versus Grassmann-Biot-Savart's law. Then we
make a review of modern experiments related to this topic and to the electric
field generated by a steady and stationary neutral current. Finally we analyse
some theoretical aspects of Weber's law as its extension through retarded
potentials to include electromagnetic radiation, and its relation to
alternative interpretations of experiments devised to show the mass variation
with velocity.
6.
A. K. T. Assis and P. H. Sakanaka, “High frequency electromagnetic
waves in a bounded, magnetized and warm plasma,” Revista Brasileira
de Física, Vol. 20, pp. 356-376 (1990). Abstract: The electromagnetic waves in
a uniform, magnetized plasma, bounded by a cylindrical waveguide are studied
using warm plasma theory. In the case of a cold plasma, backward
electromagnetic waves are obtained which exhibit the phenomenon of Faraday
rotation, in contrast to the Trivelpiece and Gould electrostatic modes which do
not show this characteristic. Numerical results are presented for the linear
LISA machine. A generalization of the Ghosh and Pal dispersion relation for a
warm, magnetized plasma is derived.
5.
P. H. Sakanaka and A. K. T. Assis, “Mode
conversion of global modes in a uniform cylindrical magnetized plasma,”
Proc. of the IV Latin-American Workshop on Plasma Physics, A. B. Rodrigo (ed.),
(CNEA Editora, Buenos Aires, 1990), pp. 203-206. Abstract: The propagation of
electromagnetic waves in a uniform magnetized plasma, bounded by a cylindrical
conducting wall is studied using the two-fluid theory, with the pressure term
included. Taking the cylindrical coordinates and perturbation of the form
f(r)exp(ikz-intheta-iwt) we obtain a sixth order equation for the electric
field component Ez(r). Its solution is a sum of three Bessel's or modified
Bessel's functions. With appropriate boundary conditions, we obtain the
dispersion relation which is solved numerically. The main result of this study
is that the pressure term causes the mode conversion of a backward wave to
another backward wave. The backward waves are modes which propagate in a
frequency range between the plasma and upper-hybrid frequencies.
4.
A. K. T. Assis, “Deriving
Ampère's law from Weber's law,” Hadronic Journal, Vol. 13, pp.
441-451 (1990). Abstract: We correct some misconceptions in the literature
regarding Weber's law and show: (A) with it Ampère's law of force between
current elements can be derived with the modern current element, (B) what are
the correct expressions for the relative velocity and acceleration between
point charges, (C) why the acceleration terms in Weber's law are essential and
so we have arguments to show that Ritz's law is untenable, and (D) how to
develop the energy of interaction between two modern current elements.
3.
A. K. T. Assis, “Weber's
law and mass variation,” Physics Letters A, Vol. 136, pp. 277-280
(1989). Abstract: Due to the renewed interest of the last few years in Ampère
and Weber's laws of force we decided to apply Weber's law to the situation of
Bucherer's experiment. We calculate, according to Weber's expression, the force
on a charge in regions of uniform electric and magnetic fields. Then we show
that Weber's law agrees with the relativistic calculation only up to second
order, inclusive, in v/c. So the special theory of relativity remains as the
only model in perfect agreement with Bucherer's experiment.
2.
A. K. T. Assis and P. H. Sakanaka, “Dispersion
relation of a bounded, magnetized and warm plasma,” Proc. of the II
Latin-American Workshop on Plasma Physics and Controlled Thermonuclear Fusion,
R. Krikorian (ed.), (World Scientific Publications, Singapore, 1989), pp.
158-184. Abstract: The propagation of the electromagnetic waves in a cylindrical
waveguide filled with uniform magnetized plasma is studied by the warm plasma
theory. Dispersion relations are obtained for several situations, such as, zero
and finite temperature, and zero, finite and infinite magnetic field. It is
found that the waves can not be separated into transverse magnetic and
transverse electric modes; only hybrid modes are propagated. For the case of
finite magnetic field the Faraday's rotation is obtained.
1.
A. K. T. Assis, “On
Mach's principle,” Foundations of Physics Letters, Vol. 2, pp.
301-318 (1989). Abstract: We propose the postulate that the resultant force
acting on any body is zero. With this postulate and with a Weber law for
gravitation, we obtain equations of motion and conclude that all inertial
forces are due to gravitational interaction with other bodies in the universe,
as suggested by Mach. We then obtain the same value for the advance of the
perihelion of the planets as is given by general relativity. All this is
accomplished in a strictly relational theory. Finally, we relate these points
to topical questions of electrodynamics raised by the experimental studies of
Graneau and Pappas.
(B) Papers
in Portuguese (artigos em português):
45. F. L. d. Silveira, R. Axt e A. K. T. Assis, “A balança de Roberval e o
segredo do seu mecanismo,” Caderno Brasileiro de Ensino de Física,
Vol. 26, pp. 441-459 (2009). Resumo: São
apresentadas duas explicações teóricas sobre o funcionamento de uma
balança de Roberval e de uma interessante variante dessa balança.
44. J. P. M. d. C. Chaib e A. K. T. Assis, “Sobre os efeitos das correntes elétricas (segunda parte) – Tradução comentada da primeira obra de Ampère sobre eletrodinâmica,” Revista Brasileira de História da Ciência, Vol. 2, pp. 118-145 (2009). Resumo: Apresentamos a tradução comentada da segunda parte da primeira obra de A. M. Ampère sobre os fenômenos eletrodinâmicos. Nesse artigo Ampère descreve suas observações da ação entre correntes elétricas e suas conseqüências qualitativas.
43. A. K. T. Assis, M. C. D. Neves e D. S. d. L. Soares, “A cosmologia de Hubble: De um universo finito em expansão a um universo infinito no espaço e no tempo,” in: M. C. D. Neves e J. A. P. d. Silva (Editores), Evoluções e Revoluções: O Mundo em Transição (Editora Massoni e LCV Edições, Maringá, 2008), pp. 199-221. Conteúdo: Mostramos a partir de seus trabalhos que Edwin Hubble mudou suas concepções cosmológicas. Inicialmente aceitava o modelo de um universo finito em expansão. Depois passou a defender o conceito de um universo que não se expande e que é infinito no espaço e no tempo.
42. W. Weber e R. Kohlrausch, “Sobre a quantidade de
eletricidade que flui através da seção reta do circuito em correntes galvânicas,”
Revista Brasileira de História da Ciência, Vol. 1, pp. 94-102 (2008), traduzido
por A. K. T. Assis. Artigo original:
Annalen der Physik, Vol. 99, pp. 10-25 (1856), Ueber die Elektricitätsmenge,
welche bei galvanischen Strömen durch den Querschnitt der Kette fliesst.
41. C. P. Magnaghi e A. K. T. Assis, “Sobre a eletricidade excitada pelo simples contato entre substâncias condutoras de tipos diferentes – Uma tradução comentada do artigo de Volta de 1800 descrevendo sua invenção da pilha elétrica,” Caderno Brasileiro de Ensino de Física, Vol. 25, pp. 118-140 (2008). Resumo: É apresentada uma tradução completa para o português do artigo de Volta descrevendo sua invenção da pilha elétrica.
40. J. Camillo e A. K. T. Assis, “Construção de um gerador eletrostático gotejante: chuva elétrica de Kelvin,” A Física na Escola, Vol. 9, pp. 29-32 (2008). Clique aqui para ver um vídeo mostrando a faísca nesta montagem. Conteúdo: Neste trabalho construímos um gerador eletrostático no qual a alta tensão é gerada pela queda de gotas de água que estão carregadas eletricamente, sendo armazenadas em recipientes isolados eletricamente da terra. Através de uma construção simples e de baixo custo, vários conceitos relacionados à eletrostática podem ser discutidos em diferentes níveis de ensino.
39. A. K. T. Assis e F. M. d. M. Ravanelli, “Reflexões sobre o conceito de centro de gravidade nos livros didáticos,” Ciência & Ensino, Vol. 2, n. 2, junho de 2008.
38. L. A. N. d. Paula, P. Raggio e A. K. T. Assis, “Uma contribuição à construção de espelhos parabólicos,” Caderno Brasileiro de Ensino de Física, Vol. 24, pp. 338-352 (2007). Resumo: Apresentamos um novo procedimento para a construção de espelhos parabólicos utilizando materiais de baixo custo. Construímos um sistema girante composto por fios de náilon, anzóis de pesca e uma bacia de plástico. Colocamos gesso líquido na bacia e a colocamos em rotação constante em relação à Terra. Um líquido adquire um perfil parabólico ao girar com uma velocidade angular constante em um referencial inercial na presença de um campo gravitacional uniforme vertical. Ao mantermos o gesso girando por um longo tempo, ele solidifica no formato parabólico. Usamos este parabolóide de gesso solidificado como modelo para construir um contra-molde de fibra de vidro e resina. Sobre este contra-molde esticamos papel laminado e em seguida despejamos gesso pastoso sobre ele. Com isto obtém-se um espelho parabólico feito de papel laminado e gesso. Nosso objetivo aqui é apenas o de apresentar um procedimento novo para a construção de espelhos parabólicos utilizando materiais de baixo custo. Isto permite que este procedimento seja explorado por professores e alunos de ensino médio e universitário.
37. M. P. Souza Filho, J. P. M. C. Chaib, J. J. Caluzi e A. K. T. Assis, “Demonstração didática da interação entre correntes elétricas,” Revista Brasileira de Ensino de Física, Vol. 29, pp. 605-612 (2007). Resumo: Apresentamos a primeira experiência crucial de Ampère mostrando a interação entre dois fios metálicos conduzindo correntes constantes. Discutimos sua importância na história da física. Descrevemos uma reprodução moderna dos procedimentos e observações de Ampère com materiais de baixo custo.
36. J. T. Lloyd, “Lorde Kelvin demonstrado,” Revista Brasileira de Ensino de Física, Vol. 29, pp. 499-508 (2007). Tradução de A. K. T. Assis. Resumo: Tradução do artigo “Lord Kelvin demonstrated”, The Physics Teacher 18, 16-24 (1980).
35. J. P. M. d. C. Chaib e A. K. T. Assis, “Sobre os efeitos das correntes elétricas – Tradução comentada da primeira obra de Ampère sobre eletrodinâmica,” Revista da Sociedade Brasileira de História da Ciência, Vol. 5, pp. 85-102 (2007). Resumo: Apresentamos a tradução comentada da primeira obra de A. M. Ampère sobre os fenômenos eletrodinâmicos. Neste artigo Ampère descreve suas observações da ação entre correntes elétricas e suas conseqüências qualitativas.
34. J. P. M. C. Chaib e A. K. T. Assis, “Ampère e a origem do magnetismo terrestre,” Anais do I Simpósio de Pesquisa em Ensino e História de Ciências da Terra e do III Simpósio Nacional sobre Ensino de Geologia no Brasil, P. W. Gonçalves et al. (orgs.), (Campinas, Instituto de Geociências da Unicamp, 2007), pp. 315-320. Resumo: Em 1820 Oersted descobriu que um longo fio com corrente alterava a orientação natural de uma agulha magnética colocada em suas proximidades. Ampère interpretou esta experiência como sendo devida a uma interação direta entre correntes elétricas existentes no ímã e no fio. Assim, para fundamentar sua posição, realizou uma série de experiências para estabelecer uma analogia entre os fenômenos magnéticos (interação entre ímãs ou entre ímãs e a terra) e os fenômenos que denominou de eletrodinâmicos (interação entre correntes). E no mesmo artigo em que apresentou experiências confirmando suas previsões, argumentou então que não existe razão em diferenciar a ação de um fio com corrente sobre um ímã, da ação magnética da terra sobre o mesmo ímã, ou mesmo da ação de um ímã sobre outro ímã. Ampère foi o primeiro a apresentar a hipótese de que o magnetismo terrestre é devido a correntes elétricas no interior da própria terra.
33. J. P. M. C. Chaib e A. K. T. Assis, “Distorção da obra eletromagnética de Ampère nos livros didáticos,” Revista Brasileira de Ensino de Física, Vol. 29, pp. 65-70 (2007). Resumo: Analisamos como alguns livros didáticos representativos apresentam a obra eletromagnética de Ampère. Mostramos que as informações apresentadas são distorcidas e que não correspondem à realidade histórica. Isto leva a uma visão errônea da evolução da física e da formulação de suas leis.
32. J. P. M. C. Chaib e A. K. T. Assis, “Experiência de Oersted em sala de aula,” Revista Brasileira de Ensino de Física, Vol. 29, pp. 41-51 (2007). Resumo: Em 1820 Oersted observou a deflexão de um pequeno ímã colocado próximo a um fio com corrente constante. Esta descoberta fundamental desencadeou uma série de pesquisas que levou à unificação dos fenômenos elétricos e magnéticos. Este artigo visa contribuir para o resgate da relevância da experiência de Oersted. É feita uma breve contextualização histórica desta experiência. Descreve-se uma reprodução moderna dos procedimentos e observações de Oersted com materiais de baixo custo.
31. A. K. T. Assis e J. P. M. C. Chaib, “Nota sobre o magnetismo da pilha de Volta – tradução comentada do primeiro artigo de Biot e Savart sobre eletromagnetismo,” Cadernos de História e Filosofia da Ciência, Vol. 16, pp. 303-309 (2006). Resumo: É feita uma tradução comentada do primeiro trabalho de Biot e Savart sobre eletromagnetismo. Eles passaram uma corrente constante em um longo fio retilíneo e observaram a posição de equilíbrio de uma pequena agulha imantada colocada próxima ao fio. Depois mediram o período para pequenas oscilações da agulha ao redor desta posição de equilíbrio, para diferentes distâncias da agulha ao fio. Concluíram que o torque magnético exercido pelo fio sobre a agulha é inversamente proporcional à distância entre o fio e o centro da agulha. Expressaram este fato em termos da força magnética exercida pelo fio sobre moléculas magnéticas na agulha. A força que atua sobre as moléculas seria perpendicular à linha ligando cada molécula ao fio e perpendicular ao eixo do fio, com sua intensidade sendo inversamente proporcional à distância ao fio.
30. A. K. T. Assis, “Interações na física – ação à distância versus ação por contato,” in: Estudos de História e Filosofia das Ciências: Subsídios para Aplicação no Ensino, C. C. Silva (org.), (Editora Livraria da Física, São Paulo, 2006), pp. 87-102. Resumo: Comparamos como ocorrem as interações na física de acordo com os modelos de ação à distância e de ação por contato.
29. A. K. T. Assis, “Derivando a lei do pêndulo experimentalmente, obtendo a aceleração da gravidade e discutindo a liberdade acadêmica,” in: De Experimentos, Paradigmas e Diversidades no Ensino de Física: Construindo Alternativas; M. C. D. Neves e A. A. Savi (editores), (Editora Massoni, Maringá, 2005), pp. 127-144.
28. A. K. T. Assis e W. Bagni Jr., “Tradução de um texto de James Clerk Maxwell sobre a teoria das cargas-imagem,” Caderno Brasileiro de Ensino de Física, Vol. 22, pp. 95-104 (2005). Resumo: Apresentamos uma tradução para o português de um importante trabalho de James Clerk Maxwell (1831-1879) publicado em 1881 sobre a teoria das cargas-imagem.
27. Arquimedes, “Sobre o equilíbrio dos planos (segunda parte),” introdução e tradução de A. K. T. Assis e N. B. F. Campos, Revista da Sociedade Brasileira de História da Ciência, Vol. 2, pp. 146-157 (2004). Resumo: Esta é a tradução da segunda parte do texto de Arquimedes sobre o equilíbrio dos planos. A primeira parte do trabalho foi publicada na Revista da Sociedade Brasileira de História da Ciência (n. 18, p. 81-94, jul./dez. 1997). Nesta segunda parte, o resultado mais importante obtido por Arquimedes é o centro de gravidade de um segmento parabólico.
26. A. C. Tort, A. M. Cunha e A. K. T. Assis, “Uma tradução comentada de um texto de Maxwell sobre a ação a distância,” Revista Brasileira de Ensino de Física, Vol. 26, pp. 273-282 (2004). Resumo: Apresentamos uma tradução comentada de um importante texto de James Clerk Maxwell publicado em 1873. Neste artigo Maxwell discute argumentos a favor e contra a ação a distância.
25. A. K. T. Assis, “Tradução de uma obra de Gauss,” Revista Brasileira de Ensino de Física, Vol. 25, pp. 226-249 (2003). Resumo: Apresentamos a primeira tradução para o português do trabalho fundamental de Gauss que é a base do sistema absoluto de medidas eletromagnéticas.
24. A. K. T. Assis e O. Pessoa Jr., “Erwin Schrödinger e o princípio de Mach,” Cadernos de História e Filosofia da Ciência, Vol. 11, pp. 131-152 (2001). Resumo: Apresentamos os conceitos de inércia, espaço e tempo na mecânica newtoniana. Analisamos o princípio de Mach, segundo o qual a inércia de qualquer corpo é devida a sua interação com os corpos distantes do universo. Em seguida explicamos porque, em geral, a teoria da gravitação de Einstein não implementa este princípio. Discutimos então o trabalho de Erwin Schrödinger que apresenta uma formulação alternativa para a mecânica baseada numa lei de Weber para a gravitação e que é compatível com as idéias de Mach.
23. J. A. Hernandes e A. K. T. Assis, “Propagação de sinais em condutores segundo a eletrodinâmica de Weber,” Ciência e Natura, Vol. 23, pp. 7-26 (2001). Resumo: Neste artigo calculamos a equação da telegrafia através da teoria eletrodinâmica de Weber. Isto é feito para condutores de diversos formatos. Comparamos os resultados obtidos com os preditos pelo eletromagnetismo clássico.
22. A. K. T. Assis, “Comparação entre a mecânica relacional e a relatividade geral de Einstein,” In: Fundamentos da Física 2 - Simpósio David Bohm, O. Pessoa Jr. (organizador), (Editora da Livraria da Física, São Paulo, 2001), pp. 27-38. Resumo: Apresenta-se o conceito de inércia como formulado por Newton e dois resultados fundamentais que obteve com sua lei da gravitação universal: a força resultante exercida por uma casca esférica num ponto material dentro ou fora dela. Utilizam-se estes resultados para analisar sua famosa experiência do balde. Discutem-se as críticas de Mach à formulação newtoniana da inércia e sua interpretação da experiência do balde. Apresentam-se as opiniões de Einstein sobre estes temas e os resultados obtidos com a Relatividade Geral. Comparam-se criticamente estes resultados com aqueles obtidos pela força de Weber para a gravitação.
21. A. K. T. Assis, “A primeira medida eletromagnética da velocidade da luz por Weber e Kohlrausch,” Anais do VII Seminário Nacional de História da Ciência e da Tecnologia, J. L. Goldfarb e M. H. M. Ferraz (organizadores), (Editora da Universidade de São Paulo, Editora da Unesp, Imprensa Oficial do Estado, Sociedade Brasileira de História da Ciência, São Paulo, 2000), pp. 65-71. Resumo: Neste trabalho analiso a primeira medida experimental da razão entre a unidade eletrodinâmica e a unidade eletrostática de carga, realizada por Weber e Kohlrausch em 1855-56. Com isto obtiveram também a razão entre as unidades eletromagnética e eletrostática de carga, que é a quantidade anterior dividida por raiz quadrada de 2. Esta última grandeza teve como valor experimental 3 X 10^8 m/s, que é o mesmo valor que a velocidade da luz no vácuo. Discuto também o significado desta grandeza na eletrodinâmica de Weber e seu aparecimento em 1846. São apresentados e comparados diversos sistemas de unidades. Analisa-se também os trabalhos independentes de Weber e Kirchhoff, de 1857, sobre a propagação de sinais eletromagnéticos em condutores metálicos. Ambos obtiveram a partir da eletrodinâmica de Weber que estes sinais caminham em circuitos de baixa resistividade com a velocidade da luz no vácuo. Tudo isto foi feito antes de Maxwell desenvolver sua teoria eletromagnética da luz em 1861-64.
20. J. A. Hernandes e A. K. T. Assis, “Propagação de sinais em condutores com a eletrodinâmica de Weber e comparação com o eletromagnetismo clássico,” Anais do XXI Encontro Nacional de Física de Partículas e Campos (23 a 27/10/2000, São Lourenço, MG). Resumo: Neste trabalho apresentamos um estudo sobre a equação da telegrafia, pioneiramente obtida por Kirchhoff e Weber. Seguimos o procedimento adotado por Kirchhoff para derivar esta equação. Consideramos casos não tratados na literatura. Concluímos que a teoria de Weber leva à equação da telegrafia.
19. A. K. T. Assis, “Discriminação na ciência,” In: Discriminação, editores: M. T. Viana e L. O. L. Renault (Editora LTR, São Paulo, 2000), pp. 285-297. Resumo: São discutidos aspectos sociais, educacionais e lingüistícos ligados com a discriminação na ciência. São analisados aspectos de discriminação exercidos pelos próprios cientistas contra outros cientistas.
18. A. K. T. Assis e J. A. Hernandes, “Cargas superficiais em placas condutoras com correntes constantes,” Anais do XX Encontro Nacional de Física de Partículas e Campos (25 a 29/10/99, São Lourenço, MG). Resumo: Estudamos a existência de campos elétricos fora de condutores com corrente constante e sua relação com as cargas superficiais que geram as correntes. Obtemos resultados novos para condutores em forma de placas. Comparamos nossos resultados teóricos com dados experimentais.
17. A. K. T. Assis e J. A. Hernandes, “A repulsão coulombiana não explica o fenômeno da explosão de fios,” Acta Scientiarum, Vol. 21, pp. 837-839 (1999). Resumo: Neste artigo, consideramos o fenômeno da explosão de fios que acontece quando flui uma alta corrente elétrica. Apresentamos o resultado da tensão coulombiana. Esta tensão é gerada pelo aparecimento de densidades de carga no fio, devido ao efeito Hall radial. Concluímos que esta tensão é várias ordens de grandeza inferior àquela necessária para romper um fio metálico.
16. A. Zylbersztajn e A. K. T. Assis, “Sobre a possível realidade das forças fictícias: uma visão relacional da mecânica,” Acta Scientiarum, Vol. 21, pp. 817-822 (1999). Resumo: Com base no princípio de Mach, pode-se considerar as forças de inércia, também chamadas forças fictícias, como reais. Neste artigo, apresentamos as idéias de Mach no contexto histórico das críticas à noção newtoniana de espaço absoluto e analisamos a Primeira Lei de Newton, normalmente aceita sem maiores discussões no ensino da mecânica. A seguir, mostramos como aquelas idéias podem ser quantitativamente implementadas através de uma mecânica relacional, segundo a qual as forças de inércia são interpretadas como resultando das interações entre massas locais e a matéria distante no universo. Algumas implicações para o ensino são mencionadas na conclusão.
15. A. K. T. Assis, “Discussão sobre o conceito de ciência,” Episteme, Vol. 9, pp. 127-129 (1999). Resumo: Resenha do livro O Que É Uma Teoria Científica? - Uma Breve Provocação Sobre Um Tema Complexo, de Jenner B. Bastos Filho (Edufal, Maceió, 1998), 144 páginas.
14. A. K. T. Assis, “Resenha de livro: Circuitos Elétricos, Magnéticos e Teoria Eletromagnética, por Y. Burian Jr.,” Boletim Eletrônico da Sociedade Brasileira de Matemática Aplicada e Computacional, Vol. III (1999). Resumo: Resenha do livro Circuitos Elétricos, Magnéticos e Teoria Eletromagnética, de Yaro Burian Jr. (Ábaco Livraria Ltda., Faculdade de Engenharia Elétrica e de Computação da Unicamp, Campinas, 1996), 101 páginas.
13. A. K. T. Assis, “Resenhas - O Mago que Veio do Céu, por M. C. D. Neves e L. R. Gardesani,” Revista Brasileira de Ensino de Física, Vol. 21, pp. 556-557 (1999). Resumo: Resenha do livro O Mago que Veio do Céu, de M. C. D. Neves, com ilustrações de L. R. Gardesani (EDUEM, Maringá, 1998), 72 páginas.
12. A. K. T. Assis, “O conceito de massa na mecânica relacional e na relatividade geral,” In: Anais do IV Simpósio de Pesquisa e Extensão em Tecnologia (Centro de Tecnologia - UFRN - Natal, 1999), Seção 7, páginas 191-192, editores: H. C. C. Fernandes, L. F. F. Moreira e A. R. O. Guerra. Resumo: Mostramos que massa é um conceito absoluto tanto na mecânica clássica quanto na teoria da relatividade geral de Einstein. Este aspecto foi criticado por Ernst Mach, que acreditava que a massa devia ser um conceito relativo na física (apenas razões de massas deviam ser importantes nos fenômenos). Mostramos que com a mecânica relacional as idéias de Mach são implementadas quantitativamente.
11. A. K. T. Assis, “Newton e suas grandes obras: o Principia e o Óptica,” In: Linguagens, Leituras e Ensino da Ciência, M. J. P. M. de Almeida and H. C. da Silva (editors), (Mercado de Letras/Associação de Leitura do Brasil, Campinas, 1998), pp. 37-52. Assunto: Comparam-se as semelhanças e diferenças dos dois principais livros publicados por Isaac Newton, o Principia e o Óptica.
10. A. K. T. Assis, “Comparação entre as eletrodinâmicas de Weber e de Maxwell-Lorentz,” Episteme, Vol. 3, pp. 7-15 (1998). Resumo: Ampresentam-se as origens históricas e comparam-se as principais características e propriedades das eletrodinâmicas desenvolvidas por Weber e por Maxwell-Lorentz. A primeira baseia-se diretamente nas cargas elétricas e na interação entre elas, enquanto que a segunda tem como base os campos elétricos e magnéticos. Discutem-se nestas duas teorias as leis de conservação e de ação e reação, assim como a propagação de sinais eletromagnéticos. Analisam-se experiências que podem distinguir estas duas eletrodinâmicas, em particular uma casca esférica uniformemente carregada com uma partícula teste sendo acelerada em seu interior por outros corpos. De acordo com a eletrodinâmica de Weber a casca deve atuar sobre a partícula teste, o que não deve ocorrer de acordo com a eletrodinâmica de Maxwell-Lorentz já que a casca carregada não gera campos elétricos nem magnéticos em seu interior. São fornecidas ordens de grandeza para estes efeitos e discutidos os aspectos filosóficos destas duas teorias.
9. A. K. T. Assis, “Sobre o equilíbrio dos planos, tradução comentada de um texto de Arquimedes,” Revista da Sociedade Brasileira de História da Ciência, Vol. 18, pp. 81-94 (1997). Resumo: Esta é uma tradução do tratado de Arquimedes intitulado Sobre o Equilíbrio dos Planos ou Sobre o Centro de Gravidade dos Planos. Neste trabalho Arquimedes apresenta um dos princípios fundamentais da estática, a lei da alavanca.
8. A. L. Xavier Jr. and A. K. T. Assis, “Schrödinger, Reissner, Weber e o princípio de Mach,” Revista da Sociedade Brasileira de História da Ciência, Vol. 17, pp. 103-106 (1997). Resumo: Apresentamos uma tradução comentada de um texto de Erwin Schrödinger sobre seu artigo intitulado "O cumprimento do postulado de relatividade na mecânica clássica," trabalho que já traduzimos para o português.
7. A. K. T. Assis, "Resenha de livro: La Mécanique de Lagrange - Principes et Méthodes," Revista da Sociedade Brasileira de História da Ciência, Vol. 18, pp. 95-96 (1997). Resumo: Resenha do livro La Mécanique de Lagrange - Principes et Méthodes, de Wilton Barroso Filho, Éditions Karthala, Paris, 1994, 333 páginas, ISBN: 2-86537-482-3.
6. A. K. T. Assis, “A experiência do balde de Newton,” In: Reflexões sobre os Fundamentos da Física Moderna, A. F. Siqueira and J. B. Bastos Filho (eds.), (Edufal, Maceió, 1997), pp. 49-61. Assunto: Discute-se a experiência realizada por Newton, as críticas à interpreção de Newton apresentada por Ernst Mach e como esta experiência é interpretada na mecânica relacional.
5. A. K. T. Assis, “Sobre os corpos flutuantes - tradução comentada de um texto de Arquimedes,” Revista da Sociedade Brasileira de História da Ciência, Vol. 16, pp. 69-80 (1996). Resumo: Esta é uma tradução do tratado de Arquimedes intitulado Sobre os Corpos Flutuantes. Neste trabalho Arquimedes apresenta o princípio fundamental da hidrostática.
4. A. K. T. Assis, “A eletrodinâmica de Weber e seus desenvolvimentos recentes,” Ciência e Natura, Vol. 17, pp. 7-16 (1995). Resumo: É apresentada a eletrodinâmica desenvolvida por Wilhelm Weber e suas principais propriedades (conservação do momento linear, do momento angular e da energia). Indica-se o fato de se derivar as equações de Maxwell a partir da eletrodinâmica de Weber. Também a força entre elementos de corrente de Ampère pode ser derivada a partir dela. Apresentam-se resultados experimentais relacionados com a eletrodinâmica de Weber tais como: experimentos ligados com a força de Ampère e com a força de Grassmann-Biot-Savart; e a existência ou não de um campo elétrico devido a uma corrente elétrica neutra, constante e estacionária. Por último discute-se desenvolvimentos recentes da eletrodinâmica de Weber: introdução do tempo retardado; a existência de termos de ordem superior a v^2/c^2; e a possibilidade de derivação da gravitação a partir de uma generalização da força de Weber.
3. A. L. Xavier Jr. and A. K. T. Assis, “O cumprimento do postulado de relatividade na mecânica clássica - Uma tradução comentada de um texto de Erwin Schrödinger sobre o princípio de Mach,” Revista da Sociedade Brasileira de História da Ciência, Vol. 12, pp. 3-18 (1994). Clique aqui para ver a errata deste artigo. Resumo: Apresentamos uma tradução comentada de um importante artigo de Erwin Schrödinger sobre o princípio de Mach: Annalen der Physik, Volume 77, páginas 325-336 (1925), Die Erfüllbarkeit der Relativitätsforderung in der klassischen Mechanik.
2. A. K. T. Assis, “Teorias de ação a distância - Uma tradução comentada de um texto de James Clerk Maxwell,” Revista da Sociedade Brasileira de História da Ciência, Vol. 7, pp. 53-76 (1992). Resumo: Apresentamos uma tradução comentada do último capítulo do livro A Treatise on Electricity and Magnetism, de J. C. Maxwell. Neste capítulo Maxwell discute as teorias eletromagnéticas de ação a distância proposta por Gauss, Weber, Riemann, Neumann, etc. Comentamos o trabalho de Maxwell e enfatizamos a relação de vários dos tópicos aqui discutidos com experimentos recentes ligados com a eletrodinâmica clássica.
1. A. K. T. Assis, “Wilhelm Eduard Weber (1804-1891) - Sua vida e sua obra,” Revista da Sociedade Brasileira de História da Ciência, Vol. 5, pp. 53-59 (1991). Resumo: É apresentada a vida de Weber, suas principais realizações experimentais e teóricas, e os desenvolvimentos recentes de sua teoria.
(C) Miscellaneous Publications
(Publicações Extras):
5.
A. K. T. Assis, M. C. D. Neves and D. S. L. Soares, “Hubble’s cosmology: From a finite expanding
universe to a static endless universe,” arXiv:0806.4481v1 [astro-ph].
Abstract: We analyze the views of Edwin Hubble
(1889-1953) as regards the large scale structure of the universe. In
1929 he initially accepted a finite expanding universe in order to explain the
redshifts of distant galaxies. Later on he turned to an infinite stationary
universe and a new principle of nature in order to explain the same phenomena.
Initially, he was impressed by the agreement of his redshift-distance relation
with one of the predictions of de Sitter's cosmological model, namely, the so-called
``de Sitter effect'', the phenomenon of the scattering of material particles,
leading to an expanding universe. A number of observational evidences, though,
made him highly skeptical with such a scenario. They were better accounted for
by an infinite static universe. The evidences he found were: (i) the huge
values he was getting for the ``recession'' velocities of the nebulae (1,800
km/s in 1929 up to 42,000 km/s in 1942, leading to v/c = 1/7), with the
redshifts interpreted as velocity-shifts. All other known real velocities of
large astronomical bodies are much smaller than these. (ii) The ``number
effect'' test, which is the running of nebulae luminosity with redshift. Hubble
found that a static universe is, within the observational uncertainties, slightly
favored. The test is equivalent to the modern ``Tolman effect'', for galaxy
surface brightnesses, whose results are still a matter of dispute. (iii) The
smallness of the size and the age of the curved expanding universe, implied by
the expansion rate that he had determined, and, (iv) the fact that an uniform
distribution of galaxies on large scales is more easily obtained from galaxy
counts, when a static and flat model is
considered. In an expanding and closed
universe, Hubble found that homogeneity was only obtained at the cost of a
large curvature. We show, by quoting his works, that Hubble remained cautiously
against the big bang until the end of his life, contrary to the statements of
many modern authors. In order to account for redshifts, in a non-expanding
universe, Hubble called for a new principle of nature, like the ``tired-light''
mechanism proposed by Fritz Zwicky in 1929. On the other hand, he was aware of
the theoretical difficulties of such a radical assumption. Hubble's approach to
cosmology strongly suggests that he would not agree with the present status of
the modern cosmological paradigm, since he was, above all, driven by
observations and by the consequences derived from them.
4.
E. Lerner et al., “An open
letter to the scientific community,” New Scientist, Vol. 182, p. 20 (
3. A. K. T. Assis e L. F. Haruna, “Tradução de um trabalho de Faraday sobre indução de correntes,” (paper in Portuguese), (2004). Resumo: Apresentamos uma tradução para o português da primeira parte do trabalho de Faraday de 1831 onde ele apresenta sua descoberta fundamental da indução de correntes.
2.
A. K. T. Assis, “The unit
of the angle and the angular equations,” Revista Physicae, Vol. 1,
pp. 55-56 (2000). Abstract: It is shown that angle has unit like any other
physical quantity. It is presented a procedure to write down all angular
equations taking this into account and valid for degrees, radians and grades.
1. A. K. T. Assis, “Números perplexos,” (paper in Portuguese), The Gleb Times (Jornal do Centro Acadêmico de Física da Unicamp), Ano 1, Número 2, p. 11 (1994). Assunto: Discutimos a relação entre os números complexos e os números perplexos.
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