The dynamic analysis of managing units and sectors of economic and industrial activity

Встановлено основні залежності між продуктивністю праці та розмірами підприємства.The main dependences between labor productivity and the sizes of the enterprise and company are defined in this work

INVESTIGATION OF TWO-PHASE FLOW HYDRODYNAMICS OF HEAT EXCHANGE TUBE OUTLET FALLING FILM EVAPORATOR

Studies of hydrodynamics and heat transfer in falling film evaporators are presented in a significant number of scientific papers [1, 2, 3]. This work is devoted to the study of a distribution of a gas phase velocity and a liquid phase irrigation density at the outlet of the heat exchange tube of the falling film evaporator.This work was supported by the Russian Foundation for Basic Research (grant # 19-53-55002)

Simulation method of the low-Re flows in the packed bed technological equipment

The paper shows the semiempirical method of a numerical simulation of the low-Re flows in the packed bed technological apparatus. The proposed method is based on the Navier-Stokes equations modification by the linear momentum sources equations in the packed bed zones. It is found that the simulation error of the proposed method is not more than 6.2% for low-density finite element meshes. The average value of the simulation error is about 3.0% for all shown cases. It was found that the proposed method simulation error almost independents on the mesh density. In the main, the simulation error is determined by the linear momentum sources equations approximation error. © Published under licence by IOP Publishing Ltd

INVESTIGATION OF HYDRODYNAMIC PARAMETERS DISTRIBUTION IN HEAT EXCHANGE TUBES OF FALLING FILM EVAPORATOR

Falling film evaporators have a high heat transfer rate with relatively small volumes of the device [1, 2, 3]. It is advisable to have information about changes in hydrodynamic parameters along the length of heat exchange tubes, when developing a falling film evaporator.This work was supported by the Russian Foundation for Basic Research (grant # 19-53-55002)

Gadolinium-based hybrid ultra-low-background material for protecting the darkside20k dark matter detector from background neutrons

A laboratory technique was developed for obtaining an ultra-low-background hybrid material based on organic glass - polymethyl methacrylate (PMMA). 157Gd nuclei are used as an efficient absorber of thermal neutrons in the hybrid material. A uniform distribution of gadolinium in the PMMAmatrix is achieved by introducing he gadolinium in the form of a coordination compound -gadolinium acetylacetonate- into the hybrid materia

INVESTIGATION OF THE HYDRODYNAMICS OF MIXING TWO TECHNOLOGICAL MEDIA WITH A SMALL-SIZED AGITATOR

The existing precipitation plant uses a cascade of three reactors connected in series, each with a mixing device and a heat exchanger. Numerical simulation of mixing fluid dynamics was carried out using the ANSYS Fluent CFD code with a standard k-epsilon turbulence model and a mixture model. The study considered a two-phase model with technological media of different densities.This work was supported by the Russian Foundation for Basic Research (grant # 19-53-55002)

INVESTIGATION OF THE HYDRODYNAMICS OF MIXING TWO TECHNOLOGICAL MEDIA USING A SIX-BLADE AGITATOR

The precipitation of ammonium polyuranate is carried out in a cascade of reactors equipped with a agitator and a heat exchanger. In the course of this study, the existing mixing device was replaced by a six-blade 3D model of which is shown in Figure 1. Data ere obtained on the distribution of two technological media and flow rates in the volume of the apparatus at different operating modes of the mixing device.This work was supported by the Russian Foundation for Basic Research (grant # 19-53-55002)

IMPLEMENTATION OF A HIGH-EFFICIENT ELEMENTARY HEATER IN THE CIRCUIT OF AN EXISTING EVAPORATOR WITH THE PURPOSE OF SAVING HEATING STEAM

he paper gives a brief description of the method for producing alumina (Al2O3) by the Bayer method.This work was supported by the Russian Foundation for Basic Research (grant # 19-53-55002)

EXPERIMENTAL STUDIES OF THE PROCESS OF COOLANT EVAPORATION

Cooling lubricants based on triethanolamine (CL) are widely used in metal processing because of need for cooling in the processing area of the product, reducing tool wear, and ensuring quality of the processed surface [1, 2, 3, 4]. It is advisable to pre-concentrate the coolant for disposal.This work was supported by the Russian Foundation for Basic Research (grant # 19-53-55002)

How close can one approach the Dirac point in graphene experimentally?

The above question is frequently asked by theorists who are interested in graphene as a model system, especially in context of relativistic quantum physics. We offer an experimental answer by describing electron transport in suspended devices with carrier mobilities of several 10^6 cm^2V^-1s^-1 and with the onset of Landau quantization occurring in fields below 5 mT. The observed charge inhomogeneity is as low as \approx10^8 cm^-2, allowing a neutral state with a few charge carriers per entire micron-scale device. Above liquid helium temperatures, the electronic properties of such devices are intrinsic, being governed by thermal excitations only. This yields that the Dirac point can be approached within 1 meV, a limit currently set by the remaining charge inhomogeneity. No sign of an insulating state is observed down to 1 K, which establishes the upper limit on a possible bandgap