Revisiting surface diffusion in random deposition

An investigation of the effect of surface diffusion in random deposition model is made by analytical methods and reasoning. For any given site, the extent to which a particle can diffuse is decided by the morphology in the immediate neighbourhood of the site. An analytical expression is derived to calculate the probability of a particle at any chosen site to diffuse to a given length, from first principles. This method may become particularly important in cases where obtaining the continuum limit and solving the corresponding differential equation may not be feasible. Numerical simulation of surface diffusion in random deposition model with varying extents of diffusion are performed and their results are interpreted in the light of the analytical calculations. Systems with surface diffusion show an initial random deposition-like growth upto monolayer deposition, then a deviation due to correlation effects and eventual saturation. An explanation for this behaviour is discussed and the point of departure from the linear form is estimated analytically.     

Application of the low-frequency vibratory method for determining the paraffin crystallization onset in dispersed petroleum systems

Crystallization onset of paraffins was studied by the low-frequency vibratory method in various kinds of dispersed petroleum systems before and after introduction of additives.     

Plasma-chemical synthesis of carbon and composite nanostructure materials in an electric arc

The possibilities of plasma-chemical synthesis of carbon and composite nanomaterials in a dc electric arc are demonstrated in experiments. Synthesis of tungsten carbide nanoparticles is implemented, along with the known processes of synthesis of carbon nanostructures and metal nanoparticles.     

The properties of carbon-carbonic condensate synthesized in the plasma arc

Physical and chemical properties of carbon-carbonic condensate synthesized by the plasma-arc technology have been studied experimentally. X-ray phase analysis has been performed, the isotherms of physical adsorption and sorption ability of the synthesized material have been measured. It has been concluded that this material offers promise as a carrier of catalytic nanoparticles and effective sorbent.     

1,4‐Methano‐11a‐methyl‐4,4a,11,11a‐tetrahydro‐1H‐benzo­[b]­fluoren‐11‐one

The title compound, C₁₉H₁₆O, crystallizes with two mol­ecules of opposite chirality in the asymmetric unit. In both mol­ecules, the naphthalene and cyclo­pentanone moieties are individually planar. The two cyclo­pentane rings adopt envelope conformations, while the cyclo­hexane ring adopts a boat conformation.     

Extrapolation of accelerated thermooxidative tests to lower temperatures applying non-Arrhenius temperature functions

Extrapolations of the accelerated thermooxidative tests, based on the Arrhenius and two non-Arrhenius temperature functions, have been tested for 26 data sets. The data cover a wide range of materials from polyolefins and other polymers to biodiesel, edible oils and dried milk. It has been found that the extrapolation from high-temperature data to ambient temperature based on the Arrhenius temperature function leads to the estimations of unrealistically long durability. The best estimations corresponding most with experience are obtained for the extrapolation based on the temperature function k(T)=A _kexp(DT).     

Magnetic Parameters of Rare-Earth Chromium Borate under High Temperatures

Russian Physics Journal - The Faraday effect is used to measure the temperature dependence of the magnetic susceptibility in the temperature range from 300 to 1200 K of rare-earth chromium borates,...     

Electrophilic aryl-halogenation using N-halosuccinimides under ball-milling

We report here a methodology of chemo- and regio-selective aryl bromination and iodination using respective N-halosuccinimides at room temperature in the absence of any solvents, catalyst/additives under ball-milling condition. However, for chlorination ceric ammonium nitrate was used as additive. The coupled product succinimide, produced from the reactions, was recycled via regeneration of NBS. This methodology works with the electron-donor substituted or unsubstituted arenes.