Density, vapor pressure, and viscosity of solutions of hydrazine mononitrate in hydrazine

Density, vapor pressure, and viscosity of solutions of hydrazine mononitrate in hydrazin

Metals plated on fluorocarbon polymers

Electroplating lead on fluorocarbon polymer parts is accomplished by etching the parts to be plated with sodium, followed by successive depositions of silver and lead from ultrasonically agitated plating solutions. Metals other than lead may be electroplated on the silvered parts

Empiric Models of the Earth's Free Core Nutation

Free core nutation (FCN) is the main factor that limits the accuracy of the modeling of the motion of Earth's rotational axis in the celestial coordinate system. Several FCN models have been proposed. A comparative analysis is made of the known models including the model proposed by the author. The use of the FCN model is shown to substantially increase the accuracy of the modeling of Earth's rotation. Furthermore, the FCN component extracted from the observed motion of Earth's rotational axis is an important source for the study of the shape and rotation of the Earth's core. A comparison of different FCN models has shown that the proposed model is better than other models if used to extract the geophysical signal (the amplitude and phase of FCN) from observational data.Comment: 8 pages, 3 figures; minor update of the journal published versio

Azimuthally Symmetric Theory of Gravitation (I)

From a purely none-general relativistic standpoint, we solve the empty space Poisson equation ($\nabla^{2}\Phi=0$) for an azimuthally symmetric setting, i.e., for a spinning gravitational system like the Sun. We seek the general solution of the form $\Phi=\Phi(r,\theta)$. This general solution is constrained such that in the zeroth order approximation it reduces to Newton's well known inverse square law of gravitation. For this general solution, it is seen that it has implications on the orbits of test bodies in the gravitational field of this spinning body. We show that to second order approximation, this azimuthally symmetric gravitational field is capable of explaining at least two things (1) the observed perihelion shift of solar planets (2) that the mean Earth-Sun distance must be increasing -- this resonates with the observations of two independent groups of astronomers (Krasinsky & Brumberg 2004; Standish 2005) who have measured that the mean Earth-Sun distance must be increasing at a rate of about $7.0\pm0.2 m/cy$ (Standish 2005) to $15.0\pm0.3 m/cy$ (Krasinsky & Brumberg 2004). In-principle, we are able to explain this result as a consequence of loss of orbital angular momentum -- this loss of orbital angular momentum is a direct prediction of the theory. Further, we show that the theory is able to explain at a satisfactory level the observed secular increase Earth Year ($1.70\pm0.05 ms/yr$; Miura et al. 2009}). Furthermore, we show that the theory makes a significant and testable prediction to the effect that the period of the solar spin must be decreasing at a rate of at least $8.00\pm2.00 s/cy$.Comment: 2 figures, 2 tables, 13 pages. Accepted to MNRAS 2009 December 9. Received 2009 December 9; in original form 2009 September 5: ref. MN-09-1767-MJ.R3

A ring as a model of the main belt in planetary ephemerides

We assess the ability of a solid ring to model a global perturbation induced by several thousands of main-belt asteroids. The ring is first studied in an analytical framework that provides an estimate of all the ring's parameters excepting mass. In the second part, numerically estimated perturbations on the Earth-Mars, Earth-Venus, and Earth-Mercury distances induced by various subsets of the main-belt population are compared with perturbations induced by a ring. To account for large uncertainties in the asteroid masses, we obtain results from Monte Carlo experiments based on asteroid masses randomly generated according to available data and the statistical asteroid model. The radius of the ring is analytically estimated at 2.8 AU. A systematic comparison of the ring with subsets of the main belt shows that, after removing the 300 most perturbing asteroids, the total main-belt perturbation of the Earth-Mars distance reaches on average 246 m on the 1969-2010 time interval. A ring with appropriate mass is able to reduce this effect to 38 m. We show that, by removing from the main belt ~240 asteroids that are not necessarily the most perturbing ones, the corresponding total perturbation reaches on average 472 m, but the ring is able to reduce it down to a few meters, thus accounting for more than 99% of the total effect.Comment: 18 pages, accepted in A&

Estimating the mass of the debris disc in HD 69830

We present a method to estimate the mass of the debris disc in the HD 69830 system, which also hosts three exoplanets with Neptune-like minimum masses. By considering the range of published stellar ages, we interpret the infrared emission from the debris disc as originating from a steady state, collisional cascade of dust grains. Using dynamical survival models subjected to observational constraints, we estimate the allowed range of disc masses. If the disc has an age of about 1 Gyr, then its mass is several times that of our asteroid belt. The maximum allowed age for the disc and the number of planetesimals it contains are determined by the assumed value for the binding energy of the planetesimals. If one insists on interpreting the disc as being transient, then this mass estimate becomes an upper limit.Comment: Accepted by MNRAS. 4 pages, 2 figures. No changes from previous version, except for corrections of typographical errors and to British English (e.g., "disc"

Identification of possible non-stationary effects in a new type of vortex furnace

The article presents the results of an experimental study of pressure and velocity pulsations in the model of improved vortex furnace with distributed air supply and vertically oriented nozzles of the secondary blast. Investigation of aerodynamic characteristics of a swirling flow with different regime parameters was conducted in an isothermal laboratory model (in 1:25 scale) of vortex furnace using laser Doppler measuring system and pressure pulsations analyzer. The obtained results have revealed a number of features of the flow structure, and the spectral analysis of pressure and velocity pulsations allows to speak about the absence of large-scale unsteady vortical structures in the studied design

Justification of the two-bulge method in the theory of bodily tides

Mathematical modeling of bodily tides can be carried out in various ways. Most straightforward is the method of complex amplitudes, which is often used in the planetary science. Another method, employed both in planetary science and astrophysics, is based on decomposition of each harmonic of the tide into two bulges oriented orthogonally to one another. We prove that the two methods are equivalent. Specifically, we demonstrate that the two-bulge method is not a separate approximation, but ensues directly from the Fourier expansion of a linear tidal theory equipped with an arbitrary rheological model involving a departure from elasticity. To this end, we use the most general mathematical formalism applicable to linear bodily tides. To express the tidal amendment to the potential of the perturbed primary, we act on the tide-raising potential of the perturbing secondary with a convolution operator. This enables us to interconnect a complex Fourier component of the tidally generated potential of the perturbed primary with the appropriate complex Fourier component of the tide-raising potential of the secondary. Then we demonstrate how this interrelation entails the two-bulge description. While less economical mathematically, the two-bulge approach has a good illustrative power, and may be employed on a par with a more concise method of complex amplitudes. At the same time, there exist situations where the two-bulge method becomes more practical for technical calculations.Comment: Astronomy & Astrophysics, in pres

Dynamical determination of the Kuiper Belt's mass from motions of the inner planets of the Solar System

In this paper we dynamically determine the mass of the Kuiper Belt Objects by exploiting the latest observational determinations of the orbital motions of the inner planets of the Solar System. Our result, in units of terrestrial masses, is 0.033 +/- 0.115 by modelling the Classical Kuiper Belt Objects as an ecliptic ring of finite thickness. A two-rings model yields for the Resonant Kuiper Belt Objects a value of 0.018 +/- 0.063. Such figures are consistent with recent determinations obtained with ground and space-based optical techniques. Some implications for precise tests of Einsteinian and post-Einsteinian gravity are briefly discussed.Comment: LaTex, 12 pages, no figures, 4 tables, 27 references. One reference added. To appear in Monthly Notices of the Royal Astronomical Societ