Prospects of the use of fast neutron reactors

The aim of this article is to consider fast-neutron reactors as a source of energy which is able to replace non-renewable natural resources that are the basis of the energetics and economic stability in Russia at the moment. The advantages of this type of reactors in comparison to the modern widely used thermal reactors are shown. The main problems of construction and functioning of fast-neutron reactors are mentioned

Unraveling the deposition mechanism in a-C:H thin-film growth : a molecular-dynamics study for the reaction behavior of C3 and C3H radicals with a-C:H surfaces

In this mol.-dynamics study, we present the simulated growth of thin a-C:H films using the Brenner [Phys. Rev. B 42, 9458 (1990)] potential. These simulations are relevant for the growth of thin films, grown using low-energy hydrocarbons. In this work, we investigate the reaction mechanisms of both the linear and the cyclic isomers of C3 and C3H on an a-C:H surface. We found that the cyclic species are always more reactive as compared to the linear species, due to their lower stability. The C3 species are found to be more reactive than the C3H species, due to steric hindrance of the H atom, shielding the C atom from the surface. The different mechanisms are discussed. The resulting film properties for different flux ratios of C3 and C3H have also been investigated. It is shown that films as deposited from C3 and C3H have a low d. and show low crosslinking. A clear change in microstructure is obsd. as the ratio between the cyclic and the linear species changes. These simulations provide insights into the reaction behavior of the investigated species, and how this influences the resulting film properties. [on SciFinder (R)

Studying additional losses of standard g.652 optical fiber with protective cladding during multiple bending to develop weight control sensor

The article deals with developing an alternative to fiber-optic data transmission lines. One of the problems of telecommunication systems of the Republic of Kazakhstan operation is considered attenuation of signals in FTT data transmission systems. The main idea of using optical fiber of the G.652-656 standard, which is sufficiently sensitive to bends, has been described. Local enterprises have mastered the production of fiber-optic cables and patch cords based on the G.652 standard. Bending causes a loss of the light wave power, changes the phase of propagation of the mode and leads to signal attenuation, in which case users cannot work normally in the Internet. In this article, various types of microbends have been simulated. Microbending of a small radius optical fiber will damage it. This situation arises when the technology of installing a fiber-optic cable is violated. There have been carried out studies aimed at obtaining new scientific results related to the construction of characteristics of additional losses arising from the bending of an optical fiber depending on the number of angles, their degree and the wavelength of optical radiation. Conclusions have been drawn on the further use for the development of sensors based on the control of additional losses during microbending, as well as the development of systems for protecting information transmitted over fiber-optic lines. The studies are aimed at developing software for the numerical calculation of additional losses with an estimate of the accuracy of constructing an approximation according to the given parameters: the number of bends, the angle and wavelength of optical radiation propagating along the fiber core

CAD-Based Shielding Analysis for ITER Port Diagnostics

Radiation shielding analysis conducted in support of design development of the contemporary diagnostic systems integrated inside the ITER ports is relied on the use of CAD models. This paper presents the CAD-based MCNP Monte Carlo radiation transport and activation analyses for the Diagnostic Upper and Equatorial Port Plugs (UPP #3 and EPP #8, #17). The creation process of the complicated 3D MCNP models of the diagnostics systems was substantially accelerated by application of the CAD-to-MCNP converter programs MCAM and McCad. High performance computing resources of the Helios supercomputer allowed to speed-up the MCNP parallel transport calculations with the MPI/OpenMP interface. The found shielding solutions could be universal, reducing ports R&D costs. The shield block behind the Tritium and Deposit Monitor (TDM) optical box was added to study its influence on Shut-Down Dose Rate (SDDR) in Port Interspace (PI) of EPP#17. Influence of neutron streaming along the Lost Alpha Monitor (LAM) on the neutron energy spectra calculated in the Tangential Neutron Spectrometer (TNS) of EPP#8. For the UPP#3 with Charge eXchange Recombination Spectroscopy (CXRS-core), an excessive neutron streaming along the CXRS shutter, which should be prevented in further design iteration

The TTIK approach for neutrons

We applied Thick Target Inverse Kinematics Method for a study of resonances decaying through neutron emission. As a test we used a well-studied, because of its role in s-process in stars, $^{13}$C($\alpha$; n) reaction. The observed energy resolution for the $^{13}$C($\alpha$; n) excitation function was $\sim$60 keV, the largest contributions coming from the time structure of the beam and the thickness of the neutron detector. These measurements demonstrated the high efficiency of the approach and revealed a disagreement with R-matrix calculations based on parameters of the most recent previous analysis

Modification of the approach to the technology of preparation of samples of milk and dairy prod- ucts for the determination of the fatty acid profile using the gas chromatography method

The objects of the study are extractants and optimal extraction conditions that contribute to the full release of the substances being determined: the concentration and volume of the extractant, the extraction time and temperature regime.   This work includes the technology of sample preparation for determining the fatty acid composition of milk with a fat mass fraction of more than 3 %, which is centrifuged for 10 minutes at 10000 rpm, 20 µl of oil is taken from the centrifuged laboratory sample into a test tube from the upper part, then dissolved in 2 cm3 of organic solvent (hexane), then mixed manually for 1-2 minutes, 100 ml of sodium methylate solution of 2 molar concentration is added to the resulting solution with a pipette and the tube is closed with a stopper, then intensively mixed manually for 2 minutes, insist for 5 minutesand filter through a paper filter the top layer containing methyl esters, the resulting solution will be ready for examination by gas chromatography. The proposed new approach to technology development reduces the sample preparation time (~19 min), reduces the amount of solvent consumed by more than 10 times, minimizes the number of actions when working with samples, and requires a minimum amount of equipment

Oxide charge evolution under crystallization of amorphous Li–Nb–O films

Li–Nb–O amorphous films were deposited onto Si substrates by the radio-frequency magnetron sputtering method in an Ar environment and an Ar(60%)+O2(40%) gas mixture. A positive effective fixed oxide charge Qeff having negative, -Qeff, and positive, +Qeff, components, exists in the as-grown heterostructures. -Qeff is located near the substrate/film interface, whereas + Qeff is determined by a deficit of Li and O (vacancies) in the bulk of Li–Nb–O films. As-grown films crystallized under thermal annealing (TA) at temperatures up to 600 °C and revealed the formation of polycrystalline LiNbO3. TA at about 520 °C resulted in the formation of the second phase LiNb3O8, increasing + Qeff, and compensating -Qeff entirely. The dielectric constants of the as-grown films exhibit two peaks at the annealing temperatures of 450 °C and 550 °C, which are attributed to the total crystallization and recrystallization of the LN films under TA, respectively. © 2020 The AuthorsRussian Foundation for Basic Research, RFBR: 18-29-11062, 18-32-00959This research was supported by the Russian Foundation for Basic Research (Grant № 18-29-11062 and Grant № 18-32-00959 ). The equipment of the Ural Center for Shared Use “Modern Nanotechnology” of the Ural Federal University was used