26,878 research outputs found
High pressure gas filter system Patent
Developing high pressure gas purification and filtration system for use in test operations of space vehicle
High pressure helium purifier Patent
Apparatus and method capable of receiving large quantity of high pressure helium, removing impurities, and discharging at received pressur
Solving the characteristic initial value problem for colliding plane gravitational and electromagnetic waves
A method is presented for solving the characteristic initial value problem
for the collision and subsequent nonlinear interaction of plane gravitational
or gravitational and electromagnetic waves in a Minkowski background. This
method generalizes the monodromy transform approach to fields with nonanalytic
behaviour on the characteristics inherent to waves with distinct wave fronts.
The crux of the method is in a reformulation of the main nonlinear symmetry
reduced field equations as linear integral equations whose solutions are
determined by generalized (``dynamical'') monodromy data which evolve from data
specified on the initial characteristics (the wavefronts).Comment: 4 pages, RevTe
Proof of a generalized Geroch conjecture for the hyperbolic Ernst equation
We enunciate and prove here a generalization of Geroch's famous conjecture
concerning analytic solutions of the elliptic Ernst equation. Our
generalization is stated for solutions of the hyperbolic Ernst equation that
are not necessarily analytic, although it can be formulated also for solutions
of the elliptic Ernst equation that are nowhere axis-accessible.Comment: 75 pages (plus optional table of contents). Sign errors in elliptic
case equations (1A.13), (1A.15) and (1A.25) are corrected. Not relevant to
proof contained in pape
Self-scaled barriers for irreducible symmetric cones
Self-scaled barrier functions are fundamental objects in the theory of
interior-point methods for linear optimization over symmetric cones, of which
linear and semidefinite programming are special cases. We are classifying all
self-scaled barriers over irreducible symmetric cones and show that these
functions are merely homothetic transformations of the universal barrier
function. Together with a decomposition theorem for self-scaled barriers this
concludes the algebraic classification theory of these functions. After
introducing the reader to the concepts relevant to the problem and tracing the
history of the subject, we start by deriving our result from first principles
in the important special case of semidefinite programming. We then generalise
these arguments to irreducible symmetric cones by invoking results from the
theory of Euclidean Jordan algebras.Comment: 12 page
The Challenge of Reforming the WTO Dispute Settlement Understanding
The May 2003 deadline for the completion of the negotiations on improvements and clarifications of the Dispute Settlement Understanding (DSU) under the Doha Mandate has not been met. However, Members agreed in July 2003 to extend the deadline for the review until the end of May 2004. This article briefly summarises the past six years of negotiations on the DSU review, the most contentious issues and the systemic difficulties of the negotiations. We conclude with prospects for the forthcoming negotiations until 2004.WTO Dispute Settlement Understanding DSU Review
Social Capital, Creative Destruction and Economic Growth
The dynamic structure of profit rates for 156 US manufacturing companies is analyzed by means of fractional integration techniques as an alternative to the commolny used ARMIA models with respect to the "persistence of profits". The results show - despite the short lengths of the series - that 35,5% of the series have long range dependence and 54% are nonstationary. This is a confirmation of the strong challenge to the competitive environment hypothesis obtained by previous studies.
Collision of plane gravitational and electromagnetic waves in a Minkowski background: solution of the characteristic initial value problem
We consider the collisions of plane gravitational and electromagnetic waves
with distinct wavefronts and of arbitrary polarizations in a Minkowski
background. We first present a new, completely geometric formulation of the
characteristic initial value problem for solutions in the wave interaction
region for which initial data are those associated with the approaching waves.
We present also a general approach to the solution of this problem which
enables us in principle to construct solutions in terms of the specified
initial data. This is achieved by re-formulating the nonlinear dynamical
equations for waves in terms of an associated linear problem on the spectral
plane. A system of linear integral ``evolution'' equations which solve this
spectral problem for specified initial data is constructed. It is then
demonstrated explicitly how various colliding plane wave space-times can be
constructed from given characteristic initial data.Comment: 33 pages, 3 figures, LaTeX. Accepted for publication in Classical and
Quantum Gravit
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