Jamming and percolation of parallel squares in single-cluster growth model

This work studies the jamming and percolation of parallel squares in a single-cluster growth model. The Leath-Alexandrowicz method was used to grow a cluster from an active seed site. The sites of a square lattice were occupied by addition of the equal size $k \times k$ squares (E-problem) or a mixture of $k \times k$ and $m \times m$ ($m \leqslant k$) squares (M-problem). The larger $k \times k$ squares were assumed to be active (conductive) and the smaller $m \times m$ squares were assumed to be blocked (non-conductive). For equal size $k \times k$ squares (E-problem) the value of $p_j = 0.638 \pm 0.001$ was obtained for the jamming concentration in the limit of $k\rightarrow\infty$. This value was noticeably larger than that previously reported for a random sequential adsorption model, $p_j = 0.564 \pm 0.002$. It was observed that the value of percolation threshold $p_{\mathrm{c}}$ (i.e., the ratio of the area of active $k \times k$ squares and the total area of $k \times k$ squares in the percolation point) increased with an increase of $k$. For mixture of $k \times k$ and $m \times m$ squares (M-problem), the value of $p_{\mathrm{c}}$ noticeably increased with an increase of $k$ at a fixed value of $m$ and approached 1 at $k\geqslant 10m$. This reflects that percolation of larger active squares in M-problem can be effectively suppressed in the presence of smaller blocked squares.Comment: 11 pages, 9 figure

Percolation of the aligned dimers on a square lattice

Percolation and jamming phenomena are investigated for anisotropic sequential deposition of dimers (particles occupying two adjacent adsorption sites) on a square lattice. The influence of dimer alignment on the electrical conductivity was examined. The percolation threshold for deposition of dimers was lower than for deposition of monomers. Nevertheless, the problem belongs to the universality class of random percolation. The lowest percolation threshold (pc = 0.562) was observed for isotropic orientation of dimers. It was higher (pc = 0.586) in the case of dimers aligned strictly along one direction. The state of dimer orientation influenced the concentration dependence of electrical conductivity. The proposed model seems to be useful for description of the percolating properties of anisotropic conductors.Comment: 6 pages, 9 figures, submitted to EPJ

Spacial and temporal dynamics of the volume fraction of the colloidal particles inside a drying sessile drop

Using lubrication theory, drying processes of sessile colloidal droplets on a solid substrate are studied. A simple model is proposed to describe temporal dynamics both the shape of the drop and the volume fraction of the colloidal particles inside the drop. The concentration dependence of the viscosity is taken into account. It is shown that the final shapes of the drops depend on both the initial volume fraction of the colloidal particles and the capillary number. The results of our simulations are in a reasonable agreement with the published experimental data. The computations for the drops of aqueous solution of human serum albumin (HSA) are presented.Comment: Submitted to EPJE, 7 pages, 8 figure

Dimer percolation and jamming on simple cubic lattice

We consider site percolation of dimers (``neadles'') on simple cubic lattice. The percolation threshold is estimated as $p_c^\text{perc} \approx 0.2555 \pm 0.0001$. The jamming threshold is estimated as $p_c^\text{jamm} = 0.799 \pm 0.002$.Comment: 3 pages, 4 figures, submitted to EPJ

СИНТЕЗ И АНТИБАКТЕРИАЛЬНАЯ АКТИВНОСТЬ ЧЕТВЕРТИЧНЫХ АММОНИЕВЫХ СОЛЕЙ НА ОСНОВЕ М-ТЕРФЕНОЛА

A method for synthesis of quaternary ammonium salts containing an antioxidant (m-terphenol) fragment is developed.Разработан эффективный метод синтеза четвертичных аммониевых солей (ЧАС), содержащих в своем составе антиоксидантный (м-терфенильный) фрагмент. Установлена высокая антибактериальная активность ЧАС, содержащих алкильный радикал С12

ИССЛЕДОВАНИЕ ТЕПЛОЗАЩИТНЫХ СВОЙСТВ ПОЛИМЕРНЫХ МАТЕРИАЛОВ, СОДЕРЖАЩИХ НЕОРГАНИЧЕСКИЕ НАПОЛНИТЕЛИ

Thermal protective compositions based on polyetherimide and inorganic fillers are proposed, and their thermal characteristics are investigated. The most effective inorganic filler in thermal protective composition was established to be silicon carbide at a content of 45–50 wt. %.Предложены составы теплозащитных композиций на основе полиэфиримида и неорганических наполнителей и исследованы их термические характеристики. Установлено, что из исследованных неорганических наполнителей в составе теплозащитных композиций наиболее эффективным является карбид кремния при его содержании 45–50 мас. %

ОРГАНО-МИНЕРАЛЬНЫЕ БИОЦИДНЫЕ КОМПЛЕКСЫ НА ОСНОВЕ ПОЛИГЕКСАМЕТИЛЕНГУАНИДИНА

The methods for synthesis of biocidal systems on the basis of the products formed by the reaction of polyphosphoric acids and polyhexamethyleneguanidine have been developed. The high antibacterial activity of these hybrid products is shown.Разработаны методы синтеза гибридных органо-минеральных систем взаимодействием полифосфорной кислоты и полигексаметиленгуанидина. Установлена высокая антибактериальная активность полученных соединений. Биоциды могут быть использованы для биозащиты полимерных композиционных материалов