M. A. Bubenchikov

About a permeability of graphene pores

The present paper theoretically studies helium and helion passage through pores in a graphene sheet using classical molecular dynamics. It was found that, within the frame of the suggested model, for considerably large pores with the diameter of 0.75 nm, helium permeates much better than helion, which is quite an unexpected result in itself.

A Scheme for Hydrogen Evolution from Natural Gas

We discuss one of the schemes of hydrogen evolution from a natural gas mixture. The scheme relies on the use of membranes formed by graphene plates containing calibrated pores in the crystalline structure. We provide the description scheme and the technology for calculating interaction between gas environment molecules and nanosized molecular structures. As an example, we consider mechanisms of hydrogen atoms penetration through defects in a graphene plate.

Simple energy barrier for component mixture of natural gases

This paper investigates the ability of a test molecule to overcome the energy barrier being in the gap between spherical nanoparticles. Three particles make a primitive structural element of composite porous material. The ability of molecules to converge with nanoparticles and then to move through more powerful repulsion field defines the filtration properties of porous materials. This paper presents the investigation of carbon nanoparticles and molecules of helium and methane bombarding them. Calculations proved that methane molecules can not get through three particles if the gap equals to 3.5 nm. For helium molecules this value makes 1.02 nm. These gaps remain the same when the size of nanoparticles increases. Therefore filters for helium separated from natural gas are to have nanopores within the range from 1.02 nm to 3.5 nm.

Migration of Nanoparticles in Operating Media of Heat Exchange Systems

The paper presents a scheme of elementary calculation of thermophoresis of shaped nanoparticles (nanotubes, fullerenes, graphenes), based on the molecule direct paths model and the theorem on variation of momentum for the system: nanoparticle-molecule in λ-layer. It has been found that there is relation of thermophoresis dimensionless velocity and parameters of the task.

Permeability of nanonet structures constructed on the basis of carbon tubes

An approximate integration of a potential of paired molecular interactions over the circumferential coordinate is used to find the potential of the interaction between a molecule and an infinite carbon nanotube (CNT). Based on the obtained energy of interaction between the tube and the molecules, local effective radii of the investigated carbon structures with respect to the molecules of the separated gas mixture are found. This makes it possible to calculate permeability of a single-layer, along with a two-layer CNT packing. The conducted research allowed calculating permeability of a nanonet structure as permeability of a two-layer packing of carbon nanotubes for the first time.

The mathematical model of the chevron-arch gearing transmitter

The teeth of herringbone transmission wheels are obtained by docking two helical wheels with an opposite arrangement of teeth, which can solve the problem of the axial force. The mathematical model of coupling chevron teeth of the driving wheel in the area of their docking using the arch tooth fragment is developed. The conjugacy area surface of the driven wheel chevron teeth is obtained as the envelope of the surfaces family formed by the arched tooth during the process of the parts motion.

Numerical simulation of oil pool boundary evolution

The study of spatial distribution of hydrocarbon resources and forecasting their geographical location is of great importance for the most complete recovery of hydrocarbons from deposits. The present study gives new mathematical results in the theory of stratified fluid flow in a porous medium. This paper analyzes the evolution of oil pool boundary basing on vortex numerical model for movement of the boundary separating fluids of different densities. It presents the investigation of how the location of light fluid regarding the heavier fluid influences on the changes in the boundary between two media in case of various shifting of the well.

Mathematical modelling of differential permeability of carbon nanotubes

We study permeability of a porous element in a carbon filter - the carbon nanotube, as well as the possibility of applying this structure in the process of natural gas components separation. The filtering effect is based on intermolecular interaction between the carbon nanotube elements and molecules and atoms of various substances in a gaseous state. With respect to these graphene structures we study the internal dynamics of hydrogen, oxygen, helium, and methane molecules. The geometrical dimensions of the tubes providing differential gas permeability of components are found.

Mathematical modelling of permeability for materials composed of spherical nanoparticles

We study permeability of a compacted material consisting of spherical nanoparticles and the possibility of using this structure for separating components of natural gas. We analyze the ability of test molecules to overcome the energy barrier in gaps between rows of spherical nanoparticles. We define the tunnel of particles which is a simple structural element of a composite porous material. The ability of molecules to move closer to nanoparticles and then move in a more powerful field of repulsive forces influences filtration properties of porous materials. We consider carbon nanoparticles and bombarding molecules of helium, hydrogen, and methane. We find the geometrical dimensions of gaps providing differential permeability of natural gas components.