## Search

Now showing items 1-10 of 23

#### Multidimensional Kolmogorov-Petrovsky test for the boundary regularity and irregularity of solutions to the heat equation

(2005)

This paper establishes necessary and sufficient condition for the regularity of a characteristic top boundary point of an arbitrary open subset of ( ) for the diffusion (or heat) equation. The result implies asymptotic ...

#### Multiple positive solutions of singular discrete p-Laplacian problems via variational methods

(2005)

We obtain multiple positive solutions of singular discrete p-Laplacian problems using variational methods.

#### X-ray bursts produced by laboratory sparks in air

(2005-10-22)

X-ray observations were made during fourteen 1.5 to 2.0 m high-voltage discharges in air produced by a 1.5 MV Marx circuit. All 14 discharges generated x-rays in the ∼30 to 150 keV range. The x-rays, which arrived in ...

#### The initiation of lightning by runaway air breakdown

(2005-10-22)

A mechanism for lightning initiation by the sustained runaway breakdown of air is presented. Unlike earlior models that rely upon large cosmic-ray air showers, this mechanism uses the runaway electrons produced by the ...

#### A positive solution for singular discrete boundary value problems with sign-changing nonlinearities

(2005-03-02)

This paper presents new existence results for the singular discrete boundary value problem - Δ²u(k - 1) = g(k, u(k)) + λh(k,u(k)), k ∈ [1,T], u(0) = 0 = u(T + 1). In particular, our nonlinearity may be singular in its ...

#### DQ herculis in profile: Whole earth telescope observations and smoothed particle hydrodynamics simulations of an edge-on cataclysmic variable system

(2005-11-20)

The old nova DQ Herculis was the Whole Earth Telescope Northern Hemisphere target for the 1997 July campaign and was observed on four nights with the SARA 0.9 m telescope during 2003 June. We present updated ephemerides ...

#### Galactic cosmic-ray modulation using a solar minimum MHD heliosphere: A stochastic particle approach

(2005-12-01)

An example of Galactic cosmic-ray modulation in a fully three-dimensional heliosphere is presented here. We use a stochastic particle method to solve for modulation without requiring symmetric boundaries or fields. We ...

#### Set differential equations with causal operators

(2005-04-28)

We obtain some basic results on existence, uniqueness, and continuous dependence of solutions with respect to initial values for set differential equations with causal operators.

#### X-ray bursts associated with leader steps in cloud-to-ground lightning

(2005-01-04)

X-ray and electric field measurements were made during five nearby negative natural lightning strikes in north central Florida during the summer of 2004. The observed X-ray emission typically was detected ∼1 ms before the ...

#### A comparison between Monte Carlo simulations of runaway breakdown and terrestrial gamma-ray flash observations

(2005-11-19)

Monte Carlo simulations of the runaway breakdown of air are used to calculate the spectra of terrestrial gamma-ray flashes (TGFs), which are then compared with RHESSI and CGRO/BATSE observations. It is found that the recent ...