26,554 research outputs found
Recent developments in Vorton Theory
This article provides a concise overview of recent theoretical results
concerning the theory of vortons, which are defined to be (centrifugally
supported) equilibrium configurations of (current carrying) cosmic string
loops. Following a presentation of the results of work on the dynamical
evolution of small circular string loops, whose minimum energy states are the
simplest examples of vortons, recent order of magnitude estimates of the
cosmological density of vortons produced in various kinds of theoretical
scenario are briefly summarised.Comment: 6 pages Latex. Contribution to 1996 Cosmology Meeting, Peyresq,
Franc
Static axisymmetric spacetimes with non-generic world-line SUSY
The conditions for the existence of Killing-Yano tensors, which are closely
related to the appearance of non-generic world-line SUSY, are presented for
static axisymmetric spacetimes. Imposing the vacuum Einstein equation, the set
of solutions admitting Killing-Yano tensors is considered. In particular, it is
shown that static, axisymmetric and asymptotically flat vacuum solutions
admitting Killing-Yano tensors are only the Schwarzschild solution.Comment: 10 pages (RevTeX), TIT/HEP-253/COSMO-4
New concept in brazing metallic honeycomb panels
Aluminum oxide coating provides surface which will not be wetted by brazing alloy and which stops metallic diffusion welding of tooling materials to part being produced. This method eliminates loss of tooling materials and parts from braze wetting and allows fall-apart disassembly of tooling after brazing
Renormalisation of gravitational self interaction for wiggly strings
It is shown that for any elastic string model with energy density and
tension , the divergent contribution from gravitational self interaction can
be allowed for by an action renormalisation proportional to . This
formula is applied to the important special case of a bare model of the
transonic type (characterised by a constant value of the product ) that
represents the macroscopically averaged effect of shortwavelength wiggles on an
underlying microscopic model of the Nambu-Goto type (characterised by ).Comment: 11 pages, Latex; original 8 page version extended to include
estimates of relevant orders of magnitude. To be published in Physical
Review,
Geometric scaling in high-energy QCD at nonzero momentum transfer
We show how one can obtain geometric scaling properties from the
Balitsky-Kovchegov (BK) equation. We start by explaining how, this property
arises for the b-independent BK equation. We show that it is possible to extend
this model to the full BK equation including momentum transfer. The saturation
scale behaves like max(q,Q_T) where q is the momentum transfer and Q_T a
typical scale of the target.Comment: 4 pages, 2 figures. Talk given by G. Soyez at the "Rencontres de
Moriond", 12-19 March 2005, La Thuile, Ital
Involution products in Coxeter groups
For W a Coxeter group, let
= {w ∈ W | w = xy where x, y ∈ W and x 2 = 1 = y 2}.
It is well known that if W is finite then W = . Suppose that w ∈ . Then the minimum value of ℓ(x) + ℓ(y) – ℓ(w), where x, y ∈ W with w = xy and x 2 = 1 = y 2, is called the excess of w (ℓ is the length function of W). The main result established here is that w is always W-conjugate to an element with excess equal to zero
Staticity Theorem for Higher Dimensional Generalized Einstein-Maxwell System
We derive formulas for variations of mass, angular momentum and canonical
energy in Einstein (n-2)-gauge form field theory by means of the ADM formalism.
Considering the initial data for the manifold with an interior boundary which
has the topology of (n-2)-sphere we obtained the generalized first law of black
hole thermodynamics. Supposing that a black hole evevt horizon comprisesw a
bifurcation Killing horizon with a bifurcate surface we find that the solution
is static in the exterior world, when the Killing timelike vector field is
normal to the horizon and has vanishing electric or magnetic fields on static
slices.Comment: 10 pages, REVTEX, to published in Phys.Rev. D1
Mapping Atlantic coastal marshlands, Maryland, Georgia, using ERTS-1 imagery
Eastern coastal marshes are the most extensive and productive in the United States. A relatively low cost, moderately accurate method is needed to map these areas for management and protection. Groundbased and low-altitude aircraft methods for mapping are time-consuming and quite expensive. The launch of NASA's Earth Resources Technology Satellite has provided an opportunity to test the feasibility of mapping wetlands using small scale imagery. The test sites selected were in Chesapeake Bay, Maryland, and Ossabaw Island, Georgia. Results of the investigation indicate that the following may be ascertained from ERTS imagery, enlarged to 1:250,000: (1) upper wetland boundary; (2) drainage pattern in the wetland; (3) plant communities; (4) ditching activities associated with agriculture; and (5) lagooning for water-side home development. Conclusions are that ERTS will be an excellent tool for many types of coastal wetland mapping
Study of radiation effects in Li-doped silicon solar cells Quarterly report
Irradiation and annealing of lithium doped silicon solar cell
Study and determination of an optimum design for space utilized lithium doped solar cells Quarterly report
Hall coefficient measurements for lithium doped solar cell
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