Introduction. Two prevailing processes of planetesimal formation are proposed. The first is the gravitational instability of a dust layer (e.g., Safronov 1969, Hayashi 1972, Goldreich and Ward 1973). The second is the growth through the mutual sticking of dust particles in a turbulent nebula (Weidenschilling and Cuzzi 1993, Stepinski and Valageas 1997). We consider the first one in this study. ...

this study aimed to construct the hydrate three-phase equilibrium curves for two typical iranian gas reservoir samples using a high-pressure visual cell. to do so, complete analysis of the reservoir fluids was obtained by different techniques of composition analysis i.e. gas chromatography (gc) and detailed hydrocarbon analysis (dha). using high-pressure visual cell the hydrate phase equilibriu...

We apply a single Boltzmann-like integro-diierential equation to model pattern formation in aspect space. Dynamics of density distributions are considered in two cases. First, the distribution of organisms on the real line is investigated. A linear stability analysis reveals conditions on interactions between the organisms that lead to aggregation and periodic patterns. Use of diiusion approxim...

there are two methods for identifying formation interface in oil wells: core analysis, which is a precise approach but costly and time consuming, and well logs analysis, which petrophysists perform, which is subjective and not completely reliable. in this paper, a novel coupled method was proposed to detect the formation interfaces using gr logs. second approximation level (a2) of gr log gained...

Formation and development of bacterial biofilms in the food industry could be a cause of food contamination, compromising food safety and shelf-life. Among the factors modulating biofilm formation, this review will focus in conditions normally encountered by bacteria in food environments, especially in biofilm initiation and development. The effect of environmental factors (substratum, temperat...

A weakly nonlinear multiple-scales analysis is performed for singly resonant second-harmonic generation. Coupled amplitude equations are derived that describe pattern formation above the transverse instability threshold. The amplitude equations explain the absence of roll patterns and are in good agreement with numerical results. Ó 2000 Elsevier Science B.V. All rights reserved. PACS: 42.65.Sf;...

We extend the mechanism for noise-induced phase transitions proposed by Ibañes et al. [Phys. Rev. Lett. 87, 020601-1 (2001)] to pattern formation phenomena. In contrast with known mechanisms for pure noise-induced pattern formation, this mechanism is not driven by a short-time instability amplified by collective effects. The phenomenon is analyzed by means of a modulated mean field approximatio...

The understanding of the distribution and population structure various species in marine environment is very helpful to effectual resource management conservation. This study aimed assess ecological factors relating sea cucumber populations on rocky shores Persian Gulf. Population two were investigated along 6 intertidal sites, including Deylam, Bushehr, Dayer, Nayband, Bostaneh, Lengeh Bushehr...