We propose two algorithms to provide a full preliminary orbit of an Earthorbiting object with a number of observations lower than the classical methods, such as those by Laplace and Gauss. The first one is the Virtual debris algorithm, based upon the admissible region, that is the set of the unknown quantities corresponding to possible orbits for objects in Earth orbit (as opposed to both inter...

In general, geometries of Petrov type II do not admit symmetries in terms Killing vectors or spinors. We introduce a weaker form equations which solutions. particular, there is an analog the Penrose-Walker spinor. Some its properties, including associated conservation laws, are discussed. Perturbations Einstein complex scalar Debye potential yield solutions to linearized equations. The Weyl ten...

The linearized dynamical equation for metric perturbations in a fully general, non-vacuum, background geometry is obtained from the Hamilton variational principle applied to action up second order. We specialize our results case of traceless and transverse fluctuations, we discuss how intrinsic properties matter stress tensor can affect (and modify) process gravity wave propagation even most co...

The transition problems from one mode of steady flow to another in a pipeline with constant gradient are considered. pressure value is set at the inlet section, and an air chamber certain volume installed outlet. Modeling process compression shock wave propagation elementary section was conducted according linearized quasi-one-dimensional N.E. Zhukovskymodel, damper considered I.A. Charny model...

In this paper, we use a Hamiltonian approach to derive the equations of motion for an object relative to a circular or slightly elliptical reference orbit. By solving the Hamilton-Jacobi equation we develop constants of the relative motion called epicyclic elements. A perturbation Hamiltonian is formulated in order to derive variational equations for the “constants” via Hamilton’s equations. We...

the paper is concerned with the bifurcation of limit cycles in general quadratic perturbations of a quadratic reversible and non-hamiltonian system, whose period annulus is bounded by an elliptic separatrix related to a singularity at infinity in the poincar'{e} disk. attention goes to the number of limit cycles produced by the period annulus under perturbations. by using the appropriate p...

Pasteuria penetrans has .been identified as an important biological control agent of root-knot nematodes. In this study the use of tally thresholds was evaluated for estimating P. penetrans endospore attachment to second-stage juveniles (J2) of Meloidogyne spp. A tally threshold (T) is defined as the maximum number of individuals in a sample unit that may be treated as absent based on binomial ...

Meloidogyne incognita penetration and development were studied in roots of highly resistant (PI 96354, PI 417444), resistant (Forrest), and susceptible (Bossier) soybean genotypes. Although more second-stage juveniles (J2) had penetrated roots of PI 96354 and PI 417444 than roots of Forrest and Bossier by 2 days after inoculation, fewer J2 were present in roots of PI 96354 at 4 days after inocu...

Penetration of second-stage juveniles (J2) of Meloidogyne incognita into tomato root explants and in vitro propagated peach plantlet roots were compared. Five inoculum levels were used: 25, 50, 75, 100, and 200 J2 for tomato; and 50, 100, 200, 500, and 1,000J2 for peach. The greatest root penetration into tomato was 30% at the 75 J2 level, but the maximum penetration into peach roots was only 8...

The purpose of this article is to create a mathematical model vehicle using dynamic equations motion and simulation perturbations acting on vehicle. It assumed that the tire in car behaves linearly. Because nonlinear, will need be linearized order find transfer function between angle rotation front wheel lateral position For purpose, simple models were created, which reflect its longitudinal dy...