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Abstract The analysis of mathematical modeling results on premise heating by a gas infrared emitter (GIE) during supply and exhaust ventilation operation is presented in this article. The model is presented in a one-dimensional non-stationary setting for an incompressible medium with allowances for the radiant heat flux transfer between opaque solid surfaces in the air. The air is transparent to thermal radiation. The traditional k-ε model is used for turbulence modeling. The possibility for creating comfortable conditions in the area of a horizontal surface with different heights, imitating laboratory equipment, is analyzed.

Abstract The paper presents the results of experimental studies on the formation of thermal comfort conditions in large premises with the joint operation of gas infrared emitters and air exchange ventilation system. The values of temperatures and heat fluxes on the clothing surface under natural and mixed convection conditions were obtained. It has been established that the air exchange system operation in the premises reduces the temperature drop of the person clothes surface, respectively, a more favorable temperature condition is achieved in the working area.

Abstract A new method to visualize microwave image is presented to early non-invasive detection of breast cancer tumors. A new processing method to compute microwave images of heterogeneity in a biological environment is described here, as well as a new algorithm for accelerating the calculation of three-dimensional radio images. Sounding of synthetic phantoms with dielectric properties of breast tissue was carried out in the range of 2–8 GHz using a special radar system developed by the authors. Results show that it is possible to use this microwave imaging method to form 3D accurate images using hemispherical scan Images of tumor phantoms were obtained during probing in the 2–8 GHz range with a resolution of about 5–7 mm. According to the results of the reconstruction of three-dimensional radio images, it was revealed that the calculation time can be reduced by at least 2 times with an insignificant loss of quality.

Abstract This work investigates the processes of dissipation of the charge and energy of a pulsed electron beam in gas compositions (nitrogen, carbon dioxide and oxygen) in the presence of ammonium sulphate and nitrate. A pulsed electron beam generated by the TEA-500 accelerator (Tomsk, Russia) with an electron energy of up to 410 keV, a beam current of up to 5 kA (I0 ), and a half-amplitude voltage pulse duration of 60 ns was injected into a 46 cm long drift chamber filled with a gas mixture. The pulsed electron beam current (IFC ) passing through the drift chamber was registered using a sectioned calorimeter with beam charge monitor function, and the efficiency of the current passage of the beam was determined as the ratio qFC/q0 , where q0 is the beam charge measured at the place of its injection into the chamber drift. The pressure in the drift chamber varied (375, 560 and 760 Torr, humidity value 15% ± 5% and 50% ± 5%). The geometric dimensions of the plasma-chemical reactor for initiating plasma-chemical reactions of flue gas cleaning were determined.

Abstract The possibility to modify the holes and pipes’ inner surface with focused high-intensity low-energy ion beams was first shown in this work. The studies were carried out using an axially symmetric single-grid system for the ions’ extraction from a free plasma boundary with subsequent ballistic focusing of the ion beam. Ion implantation of the inner surface was carried out in the region of the ion beam defocusing. The studies considered the effect of a nitrogen ions’ beam with energy of 1.4 keV on the inner surface of a tube with a diameter of 20 mm made of stainless steel AISI 321. The beams were formed with a repetition rate of 40 kHz and pulse durations of 5, 7.5 and 10 μs. It is shown that the mutual deposition of the sputtered material on the tube’ opposite sides partly compensates for ion sputtering. As a result of implantation of the inner surface of a pipe made of stainless steel AISI 321, the nitride layers with a thickness of more than 15 microns with a nitrogen dopant content of 22-30 at.% were obtained.

Abstract Core conversion requires some evaluation of the reactor safety. Changes to the reactivity worth, shutdown margin, power density and material properties are crucial to the proper functioning of the reactor. The focus of this article is to study the neutron flux distribution in the reactor core and radiation damage on candidate clads. The Ghana Research Reactor-1 (GHARR-1) operates at maximum power of 30 kW in order to attain a flux of 1.0× 1012 n·cm–2·s for the high enriched uranium core. Using the GHARR-1 core geometry, considering 348 fuel pins, the multiplication factor (Keff) is calculated at enrichments of 10%, 12.5%, 16%, 20%, 30% and 90.2%. The spectrum of neutron flux generated in the 26 group is also calculated at the specified enrichments. The ion/particle interactions with the targets (clad) were studied in the Stopping and Range of Ion in Matter code to establish the best clad material based on recorded defects and vacancies generated. From the calculations and simulations, the best choice from the candidate clads based on the assessment is SiC. The calculation of the fuel campaign length gives 7.5 years. The defects sustained by the prospective clad showed low susceptibility to swelling and other forms of deformation.

Abstract The results of experiments on low-energy implantation of AISI 321 stainless steel by nitrogen ions are presented. The treatment was carried out by a pulsed beam of nitrogen ions obtained using a ballistic ion focusing system. The surface modification occurs with the formation of a two-layer structure, which is typical for ion-plasma nitriding processes of stainless steels. The thickness of the modified layer can reach 27 μm after 1 hour of ion-plasma treatment. The influence of subsequent modification of the ion-doped layer by the action on the surface of the pulsed high-current electron beam of microsecond duration is studied. The work presents the results of the studying the regularities of changes in the depth distribution of dopants, microstructure and phase composition of the modified and matrix layers by optical metallography, diffraction analysis and transmission electron microscopy.

Abstract In this work, the processes of heat transfer in a premise heated by a gas infrared emitter (GIE) are studied on the basis of numerical solution of the heat and mass transfer equations in a two-dimensional formulation. Calculations are carried out taking into account the presence of supply and exhaust ventilation in the considered area. Ventilation is required during the operation of high-intensity type GIE. The analysis of the main heat and mass transfer parameters by radiant and convective flows is carried out.