Investigation of boiling-up centers of n-pentane using high-speed video shooting in two mutually perpendicular directions

The paper presents an experiment on superheated n-pentane boiling-up in a glass capillary at atmospheric pressure using a high-speed video. The video shooting was first performed in two mutually perpendicular directions. Two obtained images allowed concluding, on which side of the vessel wall the bubble forms, and whether we observe one bubble with an image, deformed due to the curvature of the capillary, or two bubbles located nearby. These data prove the surface (heterogeneous) character of boiling-up.     

Determination of Ionol by Voltammetry and Coulometric Titration

Procedures were developed for determining ionol by voltammetry and by coulometric titration with electrogenerated chlorine using the amperometric indication of the titration end point. Possible mechanisms of ionol oxidation with electrogenerated chlorine and its electrochemical oxidation at a glassy carbon and a gold electrode were discussed. Procedures were developed for determining ionol in mineral oil in analytical ranges from 1.0 × 10^–4 to 1.0 × 10^–2 M (RSD = 9%) and from 3.0 × 10^–5 to 4.0 × 10^–3 M (RSD = 9%) using a glassy carbon and a gold electrode, respectively. The detection limits for ionol at the glassy carbon and gold electrode were 2.8 × 10^–4 and 1.0 × 10^–5 M, respectively. The detection limit in coulometric titration was 20 g/mL.     

Implications of the Marangoni effect on the onset of Rayleigh–Benard convection in a two-layer system with a deformable interface

The European Physical Journal Special Topics - The paper deals with the investigation of the implications of the Marangoni effect on the onset of Rayleigh-Benard convection in a two-layer system...     

Hydrodynamic Aspects of Confluence of Rivers with Different Water Densities

Journal of Applied Mechanics and Technical Physics - Confluences of rivers are characterized by highly complex intrabasin processes. The arising hydrodynamic aspects of river confluences have...     

Numerical modeling of liquid-waste infiltration from storage facilities into surrounding groundwater and surface-water bodies

This study focuses on the infiltration of saturated brine from liquid-waste storage facilities into the surrounding groundwater and surface-water bodies. The storage facilities are situated at the Verkhnekamsk Potassium and Magnesium Salt Deposit (Perm krai, Russian Federation); they store highly mineralized brine of potassium, sodium, and magnesium chlorides. An analytical solution of a one-dimensional equation of contaminant transport by a homogeneous steady-state groundwater flow is used to estimate the time it takes the contaminant to travel from the storage facilities to the nearest surface water body, as well as to evaluate the formation time of a stationary concentration profile, with contaminant adsorption in the porous matrix either neglected or taken into account. The contaminant concentration at the point of brine entry into the surface water body is calculated. The ANSYS Fluent software package is used for direct 3D simulation of brine infiltration into the surrounding medium. The simulation results revealed different stages of contaminant propagation in the porous medium. The contaminant was found to spread over a wide area with an almost uniform high brine concentration close to the saturation value. The contaminant reaches the nearest riverbed approximately 20 days after the start of infiltration. The estimates of the time required for the contaminant front to reach the surface water body obtained by three-dimensional simulation agree with the analytical estimates derived from a one-dimensional model. The proposed system of physical models adequately describes the hydrodynamic processes accompanying the operation of large storage facilities and can be used to predict contaminant-front propagation in the groundwater near storage facilities.     

Stability of equilibrium of a double-layer system with a deformable interface and a prescribed heat flux on the external boundaries

The stability of mechanical equilibrium of a system of two horizontal immiscible-liquid layers with similar densities is studied. The problem is solved for a prescribed heat flux on the external boundaries. Within the framework of a generalized Boussinesq approximation, which takes the interface deformation correctly into account, the onset of convection caused by heating the system from above or below is considered. Two long-wave instability modes attributable to the presence of the deformable interface and the given heat flux on the external boundaries are detected. The system response to monotonic and oscillatory disturbances with finite wavelengths is investigated. A complete stability map is constructed.     

Photochemical sulfochlorination of polyvinylthiophene

A study is made of the photochemical sulfochlorination of polyvinylthiophene, and the optimum conditions for introducing the chlorosulfonyl group determined.     

Influence of high-frequency vibration on the morphological instability in the directional crystallization of binary melts

The influence of various types of vibration on the morphological instability of the directional crystallization front in binary melts is investigated numerically under microgravity and terrestrial conditions. The vibration frequency is assumed to be high and the amplitude to be small and an averaged approach is used. It is shown that high-frequency rotational vibration generates an intense mean flow localized in the neighborhood of the crystallization front and the direction of this flow is opposite to the direction of gravity-convection flow. Under terrestrial conditions the interaction between vibration flow and gravity convection leads to the gravitational vortex being pushed away from the crystallization front. Under both terrestrial and microgravity conditions rotational vibration has a strong stabilizing action on the morphological instability and prevents the formation of an axial hollow.     

Effect of high-frequency vibrations on oriented crystallization of binary alloys

The effect of high-frequency rotational vibrations with small amplitude on the oriented crystallization of binary alloys has been numerically studied. The calculations have been made in the framework of the quasi-static approach for succinonitrile-acetone and succinonitrile-salol binary systems. It has been shown that at a large solidification rate and/or high impurity concentration both for a lighter impurity (acetone) and for a heavier one (salol) a pit is formed on the axis of symmetry during growth which accelerates the development of morphological instability. Rotational vibrations make a strong stabilizing effect. The threshold for morphological instability increases with an increase in the vibration intensity, the radial segregation of an impurity decreases, and the pit is not formed.