Laser Induced Selective Alignment of Water Spin Isomers

We consider laser alignment of ortho and para spin isomers of water molecules by using strong and short off-resonance laser pulses. A single pulse is found to create a distinct transient alignment and antialignment of the isomeric species. We suggest selective alignment of one isomeric species (leaving the other species randomly aligned) by a pair of two laser pulses.Comment: 6 pages, 4 figures, 3 table

Mathematical modeling of rainwater runoff over catchment surface and mass transfer of contaminant incoming to water stream from soil

The subject of an article is the mathematical modeling of the rainwater runoff along the surface catchment taking account the transport of pollution which permeates into the water flow from a porous media of soil at the certain areas of this surface. The developed mathematical model consists of two types of equations: the equations for calculating of the water layer thickness over the slope surface given the precipitation and evaporation, and equation of the mass transfer of impurity coming into the surface water during its filtration in zone of incomplete saturation of soil. The model also takes into account a reverse process – adsorption of impurity in soil with its low concentration or in the uncontaminated soil. Water content in the zone of incomplete saturation is determined within the approximate approach based on the model of capillary impregnation. The principal features of nonlinear differential equations are theoretically studied. In particular, it is shown that the equation for water content in this zone can become a differential equation with lagging argument.Keywords: Mathematical Modeling, Runoff, Transport of Contaminant, Catchment, Sorption, Desorption, Incomplete Saturatio

Controlling the development of the oil reservoir penetrated by a system of injecting and producing wells

© Copyright 2016.The mathematical model and software for calculation of the interconnected heat and mass transfer in the non-uniform oil reservoir and in the arbitrary located injecting and producing wells equipped with electrical submersible pumping systems are developed. Possibility of the optimal control by the operating regime of each well, its submersible equipment and oil reservoir is demonstrated by concrete examples

Contact modelling of large radius air bending with geometrically exact contact algorithm

Usage of high-strength steels in conventional air bending is restricted due to limited bendability of these metals. Large-radius punches provide a typical approach for decreasing deformations during the bending process. However, as deflection progresses the loading scheme changes gradually. Therefore, modelling of the contact interaction is essential for an accurate description of the loading scheme. In the current contribution, the authors implemented a plane frictional contact element based on the penalty method. The geometrically exact contact algorithm is used for the penetration determination. The implementation is done using the OOFEM – open source finite element solver. In order to verify the simulation results, experiments have been conducted on a bending press brake for 4 mm Weldox 1300 with a punch radius of 30 mm and a die opening of 80 mm. The maximum error for the springback calculation is 0.87° for the bending angle of 144°. The contact interaction is a crucial part of large radius bending simulation and the implementation leads to a reliable solution for the springback angle

Computer Simulation and Comparison of the Efficiency of Conventional, Polymer and Hydrogel Waterflooding of Inhomogeneous Oil Reservoirs

The oil displacement in a layered inhomogeneous reservoir using two types of physical-chemical technologies (polymer flooding and hydrogel flooding) is the subject of this research. In the first case the aqueous polymer solution of the desired concentration is injected into the porous reservoir creating the high-viscous moving fields. Unlike this technology, the hydrogel flooding is characterized by creation and evolution of the moving hydrogel field directly in porous medium in result of chemical reaction between the water solutions of two gel-forming components which one after another are injected into the oil reservoir with given time interruption. The first component is sorbed more intensively and moves slower than the second one, so when it gradually overtakes the first solution, they begin chemically react with creation of hydrogel. Special numerical methods, algorithms and computer software are developed to solve these systems of nonlinear equations, study and compare an efficiency of the oil field development at the different type of waterflooding. It is shown that creations of the moving polymer or hydrogel fields significantly increases the uniformity of oil displacement in all layers of reservoir and improve their basic exploitation parameters due to the cross-flows between layers and creation of the moving structures in the velocity field of two-phase flow. In doing so, hydrogel technology may be much more effectiveness in comparison with polymer flooding

A two-phase and diffusion transport model for the migration of high-density organic liquids in heterogeneous aquifers

A new mathematical model describing the migration of high-density organic liquids in heterogeneous aquifers is presented. The model consists of interconnected equations of two-phase filtration and diffusion at the interface of the two liquids. The features of the different cases of pollutant migration are analyzed on the basis of computer simulation

Karst faults: mechanism of evolution and its modelling

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Investigation of flows in boundary layers in processes of thin-layer separation

Analytical expressions have been obtained to determine lateral profiles of velocity distribution in boundary layers of separated phases, when monodisperse emulsions are separated. Equations, determining the thickness of boundary layers, have been formulated. The general picture of phase flows in the interplate clearances of the separator has been investigated. Thus, a simplified mathematical model has been developed to investigate the process of separating a monodisperse mixture in separators

Work extremum principle: Structure and function of quantum heat engines

We consider a class of quantum heat engines consisting of two subsystems interacting via a unitary transformation and coupled to two separate baths at different temperatures $T_h > T_c$. The purpose of the engine is to extract work due to the temperature difference. Its dynamics is not restricted to the near equilibrium regime. The engine structure is determined by maximizing the extracted work under various constraints. When this maximization is carried out at finite power, the engine dynamics is described by well-defined temperatures and satisfies the local version of the second law. In addition, its efficiency is bounded from below by the Curzon-Ahlborn value $1-\sqrt{T_c/T_h}$ and from above by the Carnot value $1-(T_c/T_h)$. The latter is reached|at finite power|for a macroscopic engine, while the former is achieved in the equilibrium limit $T_h\to T_c$. When the work is maximized at a zero power, even a small (few-level) engine extracts work right at the Carnot efficiency.Comment: 16 pages, 5 figure

TEMPERATURE DEPENDENCE OF THE ELECTRON-ELECTRON INTERACTION IN THE DOPED HETEROJUNCTION

The article discusses the joint solution of the Schrödinger and Poisson equations for two-dimensional semiconductor heterojunction. The application of a triangular potential of well approximation for the calculation of the electron-electron interaction is offered in the paper. The influence of the parameters of the selected approximation was analyzed