Papers by J. Leliwa-kopystynski
We consider the satellites of the size range from Mimas or Protheus (radii 200 km) to Titania (79... more We consider the satellites of the size range from Mimas or Protheus (radii 200 km) to Titania (790 km). The lower limit is that of the smallest sphere-like bodies. The upper limit is determined by requirement that no phase transitions occurs inside the body or these transitions are only of marginal significance. Therefore, the considered bodies could be 6 satellites
High Pressure Investigations in Geosciences, 1989
The positon spectrum of Pr/sup 140/ was investigated with a long lens magnetic beta -ray spectrom... more The positon spectrum of Pr/sup 140/ was investigated with a long lens magnetic beta -ray spectrometer. The helical baffles were applied to separate the positons and electrons. The maximum energies of three beta /sup +/ components are 2366 plus or minus 12, 770 plus or minus 12, and 458 plus or minus 15 kev and their relative intensities: 1; <1.4 x 10/sup -2/; and 7.2 x 10/ sup -6/. (auth)
European Planetary Science Congress, Sep 1, 2017
High Pressure Research, 1990
ABSTRACT
Advances in Space Research, 1999
Numerical calculations of the moment of inertia and its changes due to water ice sublimation from... more Numerical calculations of the moment of inertia and its changes due to water ice sublimation from a cometary nucleus surface are presented. The comet parameters, namely size, major semi-axis, and eccentricity for the comet C/1995 O1 Hale-Bopp are assumed. The calculations are performed for different values of the thermal conductivity coefficient, and for different inclinations of the rotation axis. The
Journal de Physique, 1975
2014 Il est montré expérimentalement comment il est possible d'étudier uniquement la croissance d... more 2014 Il est montré expérimentalement comment il est possible d'étudier uniquement la croissance de la phase nouvelle. On propose des modèles mathématiques qui rendent compte de l'évolution de la transformation. Celui qui donne l'accord le plus satisfaisant correspond, dans les conditions d'expériences utilisées, à une dépendance quadratique de la croissance vis-à-vis de la surpression et à un mode de croissance monodimensionnel. Ce dernier peut toutefois varier en fonction du degré d'avancement de la transition. La comparaison théorie/expérience est faite avec RbCl. Abstract. 2014 Experimental methods for studying the growth of a solid phase during a polymorphic transition are discussed. Mathematical models are proposed to describe the kinetics of the transition. The experimental data on RbCl indicate a quadratic relationship between the growth and the overpressure, and an unidimensional mode of growth. However this mode may vary with the degree of transformation of the sample.
Earth, Moon and Planets, 1987
ABSTRACT
The accumulation process of frozen CO2 within the Martian regolith is analyzed. The boundary cond... more The accumulation process of frozen CO2 within the Martian regolith is analyzed. The boundary conditions are taken to be the periodically variable temperature at the Mars surface and the constant heat flux at the bottom of the regolith layers, some hundred meters thick. The mean value of temperature as well as its amplitude are assumed to be dependent on latitude and could be variable with the geological time scale. The flux of gaseous CO2 within the regolith is controlled by the mechanism of gas transport through the porous medium. An appropriate initial geometry of distribution of pores is assumed. The porosity and flux change due to condensation/sublimation processes. The equations of heat and mass transfer are solved numerically for a given latitude. Next, the local (over the parallel of latitude belt) annual balance of CO2 is calculated. The procedure is repeated over the whole Martian surface and next the total annual net flux is calculated.
Advances in Space Research, 1999
The two-dimensional axisymmetric hydrocode model of free particles is applied to the calculation ... more The two-dimensional axisymmetric hydrocode model of free particles is applied to the calculation of response of a comet nucleus to a meteorite impact. The nucleus is assumed to be spherical with a radius of 1 km. It is composed of a porous granular mixture of water ice and of mineral. Initial temperature is 50 K. Porosity is v = 0.6 and the mean density is p = 400 kg me3. Impactor radius is equal to 1 m and its mean density is equal to that of the nucleus. Impact velocity is 10 km se'. A normal impact is considered. Particular.forms for the equations of state (EOS) for the real medium (water ice and rock) as well as for an artificial medium of very low-density (40 kg mJ) filling up the voids are used. The cohesion is included in the constitutive model of the constituents. Numerical modelling provides the time dependent fields of pressure, density, temperature, and particle velocity in the vicinity of an impact point. The evolution of the field of temperature correlated with the function for kinetics of amorphous to crystalline phase transition permits discussion of the impact-induced crystallization of presumably initially amorphous ice. 0 1999 COSPAR. Published by Elsevier Science Ltd. MODEL OF COMET NUCLEUS There exists a large diversity in details concerning modeling of comet nuclei. However, the dominating abundance of water ice as well as the high porosity of nuclei are well established. Other features are more or less controversial. Among them is the state of the ice: amorphous or crystalline, see e.g. Rickman (199 1) and Kauchi et al. (1994). The last authors concluded: "Icy grains which formed the Uranian and Neptunian satellites and comets were initially amorphous, if they were formed from the icy grains preserved from the molecular cloud stage". The form of ice depends on temperature of formation of a comet nucleus, on contents of radioactive nuclei including short lived Al% (PriahGk et al. 1987), on history of a comet from formation epoch till the recent time, and on actual properties of comet's orbit, in particular on perihelion distances. Intrinsic radioactivity, if sufficiently intense, can heat a presumably amorphous ice and transform it to the crystalline form. Energy of solar radiation or accumulated energy of many impacts can transform ice from amorphous to crystalline form in a layer spreading downward from the surface level to a certain depth. Study of impact induced phase transition from amorphous to crystalline phase of water ice is one of the goals of this work. This phase transition driven by solar flux of energy incident on comet surface was recently studied by Podolak and Prialnik (1996). We suppose that the grains of water ice and of mineral as well as the voids are randomly mixed. They form the nucleus that is statistically or "macroscopically" uniform, Figure 1. However, our two-dimensional (2D) geometry requires axial symmetry: the z-axis follows the direction of impactor movement and is perpendicular to the target; it is directed downward into the nucleus, with z = 0 at the surface. In the 2D case the grains of ice and those of rock as
Planetary and Space Science
Journal of Glaciology
Compaction experiments on porous samples of granular ice and ice/rock mixtures were conducted at ... more Compaction experiments on porous samples of granular ice and ice/rock mixtures were conducted at low temperature, primarily to obtain rheological data useful in modeling the internal structure and evolution of icy satellites of the giant planets. The data may also be of interest for studying Earth’s glaciers and the Martian polar caps. The samples tested were prepared from three types of ice: water, carbon dioxide and ammonia; three types of rock components were also used in the samples. The time-dependent compaction of samples a few centimeters in size was studied for a range of rock contents, pressures (2.2–17.7 MPa) and temperatures (140–261 K). An Equation (16), giving the compaction rate as a function of porosity, pressure, temperature and concentration of the rock component was fitted to the observed results. The presence of rock fragments strongly inhibits the compaction process.
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Papers by J. Leliwa-kopystynski