115 research outputs found
Preliminary results on 400 fps impact tests of two 2-ft diameter containment models for mobile nuclear reactors
Impact tests of two 2-foot diameter containment models for mobile nuclear reactor
Advances in the proposed electromagnetic zero-point field theory of inertia
A NASA-funded research effort has been underway at the Lockheed Martin
Advanced Technology Center in Palo Alto and at California State University in
Long Beach to develop and test a recently published theory that Newton's
equation of motion can be derived from Maxwell's equations of electrodynamics
as applied to the zero-point field (ZPF) of the quantum vacuum. In this
ZPF-inertia theory, mass is postulated to be not an intrinsic property of
matter but rather a kind of electromagnetic drag force that proves to be
acceleration dependent by virtue of the spectral characteristics of the ZPF.
The theory proposes that interactions between the ZPF and matter take place at
the level of quarks and electrons, hence would account for the mass of a
composite neutral particle such as the neutron. An effort to generalize the
exploratory study of Haisch, Rueda and Puthoff (1994) into a proper
relativistic formulation has been successful. Moreover the principle of
equivalence implies that in this view gravitation would also be electromagnetic
in origin along the lines proposed by Sakharov (1968). With regard to exotic
propulsion we can definitively rule out one speculatively hypothesized
mechanism: matter possessing negative inertial mass, a concept originated by
Bondi (1957) is shown to be logically impossible. On the other hand, the linked
ZPF-inertia and ZPF-gravity concepts open the conceptual possibility of
manipulation of inertia and gravitation, since both are postulated to be
electromagnetic phenomena. It is hoped that this will someday translate into
actual technological potential. A key question is whether the proposed
ZPF-matter interactions generating the phenomenon of mass might involve one or
more resonances. This is presently under investigation.Comment: Revised version of invited presentation at 34th AIAA/ASME/SAE/ASEE
Joint Propulsion Conference, July 13-15, 1998, Cleveland, OH, 10 pages, no
figure
Levi-Civita Effect in the polarizable vacuum (PV) representation of general relativity
The polarizable vacuum (PV) representation of general relativity (GR),
derived from a model by Dicke and related to the "TH-epsilon-mu" formalism used
in comparative studies of gravitational theories, provides for a compact
derivation of the Levi-Civita Effect (both magnetic and electric), herein
demonstrated.Comment: 8 page
On a modified-Lorentz-transformation based gravity model confirming basic GRT experiments
Implementing Poincar\'e's `geometric conventionalism' a scalar
Lorentz-covariant gravity model is obtained based on gravitationally modified
Lorentz transformations (or GMLT). The modification essentially consists of an
appropriate space-time and momentum-energy scaling ("normalization") relative
to a nondynamical flat background geometry according to an isotropic,
nonsingular gravitational `affecting' function Phi(r). Elimination of the
gravitationally `unaffected' S_0 perspective by local composition of space-time
GMLT recovers the local Minkowskian metric and thus preserves the invariance of
the locally observed velocity of light. The associated energy-momentum GMLT
provides a covariant Hamiltonian description for test particles and photons
which, in a static gravitational field configuration, endorses the four `basic'
experiments for testing General Relativity Theory: gravitational i) deflection
of light, ii) precession of perihelia, iii) delay of radar echo, iv) shift of
spectral lines. The model recovers the Lagrangian of the Lorentz-Poincar\'e
gravity model by Torgny Sj\"odin and integrates elements of the precursor
gravitational theories, with spatially Variable Speed of Light (VSL) by
Einstein and Abraham, and gravitationally variable mass by Nordstr\"om.Comment: v1: 14 pages, extended version of conf. paper PIRT VIII, London,
2002. v2: section added on effective tensorial rank, references added,
appendix added, WEP issue deleted, abstract and other parts rewritten, same
results (to appear in Found. Phys.
Classical interpretation of the Debye law for the specific heat of solids
We derive the Debye law for the specific heat of solids within the realm of stochastic electrodynamics (i.e., classical electrodynamics with the assumption of a real zero-point field). Random lattice vibrations are generated by the Planck radiation including zero point, which is absorbed by the ions. The equilibrium is accomplished by a fluctuation-dissipation mechanism due to the emission of radiation by the ions in accelerated motion
A toy model of the five-dimensional universe with the cosmological constant
A value of the cosmological constant in a toy model of the five-dimensional
universe is calculated in such a manner that it remains in agreement with both
astronomical observations and the quantum field theory concerning the
zero-point fluctuations of the vacuum. The (negative) cosmological constant is
equal to the inverse of the Planck length squared, which means that in the toy
model the vanishing of the observed value of the cosmological constant is a
consequence of the existence of an energy cutoff exactly at the level of the
Planck scale. In turn, a model for both a virtual and a real
particle-antiparticle pair is proposed which describes properly some energetic
properties of both the vacuum fluctuations and created particles, as well as it
allows one to calculate the discrete "bare" values of an elementary-particle
mass, electric charge and intrinsic angular momentum (spin) at the energy
cutoff. The relationships between the discussed model and some phenomena such
as the Zitterbewegung and the Unruh-Davies effect are briefly analyzed, too.
The proposed model also allows one to derive the Lorentz transformation and the
Maxwell equations while considering the properties of the vacuum filled with
the sea of virtual particles and their antiparticles. Finally, the existence of
a finite value of the vacuum-energy density resulting from the toy model leads
us to the formulation of dimensionless Einstein field equations which can be
derived from the Lagrangian with a dimensionless (naively renormalized)
coupling constant.Comment: 52 pages, 1 figure; a post-final, rewritten version with a number of
new remarks and conclusion
Gedanken experiments with Casimir forces, vacuum energy, and gravity
Gedanken experiments are used to explore properties of quantum vacuum energy
that are currently challenging to explore experimentally. A constant lateral
Casimir force is predicted to exist between two overlapping finite parallel
plates at 0 K, otherwise it would be possible to extract an arbitrary amount of
energy from the quantum vacuum. A rigid unpowered object cannot be accelerated
by the quantum vacuum because of the translational symmetry of space. By
considering systems in which vacuum energy and other forms of energy are
exchanged, we demonstrate that a change {\Delta}E in vacuum energy, whether
positive or negative with respect to the free field, corresponds to an
equivalent inertial mass and equivalent gravitational mass
{\Delta}M={\Delta}E/c^2. We consider the possibility of a gravitational shield,
and show that, if it exists, the energy to operate it would have to cancel the
net energy extracted from the gravitational field, otherwise we could extract
an arbitrary amount of energy from the field.Comment: 24 pages, 3 figure
A spatially-VSL gravity model with 1-PN limit of GRT
A scalar gravity model is developed according the 'geometric conventionalist'
approach introduced by Poincare (Einstein 1921, Poincare 1905, Reichenbach
1957, Gruenbaum1973). In principle this approach allows an alternative
interpretation and formulation of General Relativity Theory (GRT), with
distinct i) physical congruence standard, and ii) gravitation dynamics
according Hamilton-Lagrange mechanics, while iii) retaining empirical
indistinguishability with GRT. In this scalar model the congruence standards
have been expressed as gravitationally modified Lorentz Transformations
(Broekaert 2002). The first type of these transformations relate quantities
observed by gravitationally 'affected' (natural geometry) and 'unaffected'
(coordinate geometry) observers and explicitly reveal a spatially variable
speed of light (VSL). The second type shunts the unaffected perspective and
relates affected observers, recovering i) the invariance of the locally
observed velocity of light, and ii) the local Minkowski metric (Broekaert
2003). In the case of a static gravitation field the model retrieves the
phenomenology implied by the Schwarzschild metric. The case with proper source
kinematics is now described by introduction of a 'sweep velocity' field w: The
model then provides a hamiltonian description for particles and photons in full
accordance with the first Post-Newtonian approximation of GRT (Weinberg 1972,
Will 1993).Comment: v1: 11 pages, GR17 conf. paper, Dublin 2004, v2: WEP issue solved,
section on acceleration transformation added, text improved, more references,
same results, v3: typos removed, footnotes, added and references updated, v4:
appendix added, improved tex
Ultraweak excitations of the quantum vacuum as physical models of gravity
It has been argued by several authors that the space-time curvature observed
in gravitational fields, and the same idea of forms of physical equivalence
different from the Lorentz group, might emerge from the dynamical properties of
the physical flat-space vacuum in a suitable hydrodynamic limit. To explore
this idea, one could start by representing the physical vacuum as a Bose
condensate of elementary quanta and look for vacuum excitations that, on a
coarse grained scale, resemble the Newtonian potential. In this way, it is
relatively easy to match the weak-field limit of classical General Relativity
or of some of its possible variants. The idea that Bose condensates can provide
various forms of gravitational dynamics is not new. Here, I want to emphasize
some genuine quantum field theoretical aspects that can help to understand i)
why infinitesimally weak, 1/r interactions can indeed arise from the same
physical vacuum of electroweak and strong interactions and ii) why, on a
coarse-grained scale, their dynamical effects can be re-absorbed into an
effective curved metric structure.Comment: 30 pages, no figures, accepted by Classical and Quantum Gravit
Induced epidermal permeability modulates resistance and susceptibility of wheat seedlings to herbivory by Hessian fly larvae
Salivary secretions of neonate Hessian fly larvae initiate a two-way exchange of molecules with their wheat host. Changes in properties of the leaf surface allow larval effectors to enter the plant where they trigger plant processes leading to resistance and delivery of defence molecules, or susceptibility and delivery of nutrients. To increase understanding of the host plant's response, the timing and characteristics of the induced epidermal permeability were investigated. Resistant plant permeability was transient and limited in area, persisting just long enough to deliver defence molecules before gene expression and permeability reverted to pre-infestation levels. The abundance of transcripts for GDSL-motif lipase/hydrolase, thought to contribute to cuticle reorganization and increased permeability, followed the same temporal profile as permeability in resistant plants. In contrast, susceptible plants continued to increase in permeability over time until the entire crown of the plant became a nutrient sink. Permeability increased with higher infestation levels in susceptible but not in resistant plants. The ramifications of induced plant permeability on Hessian fly populations are discussed
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