Calculation method for percolation thresholds in modeling porous and composite materials

A method is suggested for calculating percolation thresholds in two- and three-dimensional materials allowing for remote interaction and elongation of particles forming these materials. Calculated results are compared with known data. It is shown that it is possible to use the method when simulating elastic and plastic properties of porous materials.     

"Memory independence and memory interference in cognitive development": Correction.

Reports an error in the original article by C. J. Brainerd and V. F. Reyna (Psychological Review, 1993[Jan], Vol 100[1], 42–67). On page 56, there were some incorrect data values in the 3rd and 4th columns of Table 4. The amended table is presented. (The following abstract of this article originally appeared in record 1993-17013-001.) Recent experiments have established the surprising fact that age improvements in reasoning are often dissociated from improvements in memory for determinative informational inputs. Fuzzy-trace theory explains this memory-independence effect on the grounds that reasoning operations do not directly access verbatim traces of critical background information but, rather, process gist that was retrieved and edited in parallel with the encoding of such information. This explanation also envisions 2 ways in which children's memory and reasoning might be mutually interfering: (1) memory-to-reasoning interference, a tendency to process verbatim traces of background inputs on both memory probes and reasoning problems that simultaneously improves memory performance and impairs reasoning and (2) reasoning-to-memory interference… (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Potential fields based on circular multipole series

In the frame of cylindrical coordinates the Dirichlet outer boundary-value problem is solved on the basis of circular multipoles. A number of multipole-cylindrical fields is calculated.     

In situ13C NMR study of tert-butanol interaction with moderately concentrated sulfuric acid

An in situ NMR study of tert-butanol dehydration in 95 and 85% sulfuric acid did not indicate the formation of tert-butyl cations as active reaction intermediates. Instead, only NMR lines from oxonium ions under the condition of fast exchange with water and the acid were observed. It is most likely that, in the concentrated acid, the active intermediates of this reaction are represented by tert-butyl sulfuric ester which probably is a precursor of invisible tert-butyl carbenium ions representing short-lived excited or transition states.     

Influence of production method on direction of processing heavy Ashal'chinsk crude

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 6, pp. 7–9, June, 1992.