Brane decay of a (4+n)-dimensional rotating black hole: spin-0 particles

In this work, we study the `scalar channel' of the emission of Hawking radiation from a (4+n)-dimensional, rotating black hole on the brane. We numerically solve both the radial and angular part of the equation of motion for the scalar field, and determine the exact values of the absorption probability and of the spheroidal harmonics, respectively. With these, we calculate the particle, energy and angular momentum emission rates, as well as the angular variation in the flux and power spectra -- a distinctive feature of emission during the spin-down phase of the life of the produced black hole. Our analysis is free from any approximations, with our results being valid for arbitrarily large values of the energy of the emitted particle, angular momentum of the black hole and dimensionality of spacetime. We finally compute the total emissivities for the number of particles, energy and angular momentum and compare their relative behaviour for different values of the parameters of the theory.Comment: 24 pages, 13 figure

Brane Decay of a (4+n)-Dimensional Rotating Black Hole. II: spin-1 particles

The present works complements and expands a previous one, focused on the emission of scalar fields by a (4+n)-dimensional rotating black hole on the brane, by studying the emission of gauge fields on the brane from a similar black hole. A comprehensive analysis of the particle, energy and angular momentum emission rates is undertaken, for arbitrary angular momentum of the black hole and dimensionality of spacetime. Our analysis reveals the existence of a number of distinct features associated with the emission of spin-1 fields from a rotating black hole on the brane, such as the behaviour and magnitude of the different emission rates, the angular distribution of particles and energy, the relative enhancement compared to the scalar fields, and the magnitude of the superradiance effect. Apart from their theoretical interest, these features can comprise clear signatures of the emission of Hawking radiation from a brane-world black hole during its spin-down phase upon successful detection of this effect during an experiment.Comment: 35 pages, 19 figures, Latex fil

Research of Dosimetric Characteristics of Human Hair Depending on the Content of Melanine

Purpose: Investigation of paramagnetic properties of radiation-induced centers that occur when hair samples are irradiated with ionizing radiation, depending on the color of the sample. Material and methods: A Bruker Elexsys E580 electron paramagnetic resonance spectrometer was used. To improve the signal-to-noise ratio, the spectrum was recorded with three accumulations with a constant scan time equal to one minute. Measurements were made using a highly sensitive rectangular Bruker SuperHighQ resonator. For irradiation of samples, the linear electron accelerator UELR-10-10С2 of the innovation and implementation center for radiation sterilization of the Urals Federal University (Institute of Physics and technology) was used. Results: Research of the EPR signal parameters of the melanin in hair samples of different colors (black, brown, red and gray with different degrees of pigmentation) showed that the intensity of the EPR signal varies depending on the hair color. The higher the radiation sensitivity of the hair, the lighter the color of the hair. The melanin signal, which is the background for the radiation-induced signal, increases with increasing intensity of hair color. © 2022 State Research Center, Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency. All rights reserved.Federal Medical and Biological Agency of RussiaSouth Ural Regional Medical and Dosimetric Emergency CenterMinistry of Education and Science of the Russian Federation, Minobrnauka, (AAAA-A18-118020290104-2)The author declare no conflict of interest. The work was carried out within the framework of state contract No. 11.310.19.2 on the topic “Improving the provision of emergency preparedness and response of the South Ural Regional Medical and Dosimetric Emergency Center in the event of radiation accidents” (code “Response-19”), funded by the Federal Medical and Biological Agency of Russia. EPR measurements were partly carried out within the framework of the state order of the Ministry of Education and Science of Russia (topic "Spin", No. AAAA-A18-118020290104-2). Article was prepared with equal participation of the authors 15.03.2022. 23.04.202

Brane Decay of a (4+n)-Dimensional Rotating Black Hole. III: spin-1/2 particles

In this work, we have continued the study of the Hawking radiation on the brane from a higher-dimensional rotating black hole by investigating the emission of fermionic modes. A comprehensive analysis is performed that leads to the particle, power and angular momentum emission rates, and sheds light on their dependence on fundamental parameters of the theory, such as the spacetime dimension and angular momentum of the black hole. In addition, the angular distribution of the emitted modes, in terms of the number of particles and energy, is thoroughly studied. Our results are valid for arbitrary values of the energy of the emitted particles, dimension of spacetime and angular momentum of the black hole, and complement previous results on the emission of brane-localised scalars and gauge bosons.Comment: Latex file, JHEP style, 34 pages, 16 figures Energy range in plots increased, minor changes, version published in JHE

Digital receivers for low-frequency radio telescopes UTR-2, URAN, GURT

This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. Since 1998, digital receivers performing on-the-fly dynamic spectrum calculations or waveform data recording without data loss have been used at the UTR-2 radio telescope, the URAN VLBI system, and the GURT new generation radio telescope. Here we detail these receivers developed for operation in the strong interference environment that prevails in the decameter wavelength range. Data collected with these receivers allowed us to discover numerous radio astronomical objects and phenomena at low frequencies, a summary of which is also presented.Comment: 24 pages, 15 figure

Mathematical model of plate heat exchanger for utilisation of waste heat from condensable gaseous streams

The mathematical model of vapour condensation from the mixture with noncondensing gas in Plate Heat Exchanger (PHE) channels is presented. The model accounts for the change of process parameters along the heat transfer surface and local features of heat and mass transfer processes in PHEs channels with plates of different corrugations geometry. It consists of the system of ordinary differential equations with considerably nonlinear right parts. The software for its solution by finite difference method is developed. The validity of the model is confirmed by comparison with the experiment for steam-air mixture condensation in a PHE channel sample

Hotel as a Work of Art

Цель статьи — на основе анализа функционирования арт-отеля Lе Negresco разработать рекомендации по созданию гостиничного интерьера художественными средствами. Специфика исследования: бизнес арт-отелей постоянно нуждается в привлечении значительного количества ресурсов и внесении новых идей с целью появления большего количества потребителей и партнеров. Главные результаты: рекомендуется использовать антикварную редкую мебель для создания уникальности номера и самого отеля; соблюсти интересный эксклюзивный стиль и интерьер, использовать различные предметы искусства и грамотно сочетать их между собой; поддерживать и создавать атмосферу выбранной стилистики и жанра отеля и не пренебрегать удобствами и комфортом для будущих гостей.The purpose of the article is based on the analysis of the functioning of the art hotel Lе Negresco to develop recommendations for creating a hotel interior by artistic means. The specifics of the study: the business of art hotels constantly needs to attract a large number of resources and introduce new ideas in order to attract more consumers and partners. Main results: it is recommended to use antique rare furniture to create the uniqueness of the room and the hotel itself; observe an interesting exclusive style and interior, use various art objects and competently combine them with each other; maintain and create an atmosphere of the chosen style and genre of the hotel, and do not neglect the amenities and comfort for future guests

Improvement of Lyme Borreliosis Agent Indication Methods

On the basis of silica - aluminosilicate, modified by carboxymethylated lignin and carbodiimide, obtained are the composite microgranulated magnetic immunoadsorbents (MIA) with high adsorption activity, which are characterized by the standardized structural characteristics and mechanical strength. Application of MIAs makes it possible, at the stage of tick samples preparation, to eliminate various admixtures via reiterative irrigations of the sorbent with the infectious agent fixed on it. Therefore negative influence of admixtures on the performed analysis is excluded, and the target agent is concentrated to the maximum limit. Thus the specificity and sensitivity of PCR-analysis enhances

Авария 1957 года: радиационная обстановка и дозы облучения участников ликвидации аварии на территории промышленной площадки ПО «Маяк»

Purpose: to assess the radiation situation on the industrial site of the PA “Mayak” during the accident in 1957 and the radiation doses of the participants in the liquidation of consequences of this accident. Materials and methods: on the basis of the archival documents analysis, radiation situation data for 1957 – 1960, IDC data and calculated doses of the Mayak workers, as well as supporting organizations personnel and military units involved in the liquidation of the accident consequences and covered by individual monitoring are presented. Results: in 1957 – 1959 about 38,5 thousand people took part in the works on the territory of the PA “Mayak” industrial site for liquidation of consequences of the accident, including persons exposed at the time of the accident: employees of “Mayak”, military and civil builders. Radiation doses from 25 to 30 R received about 10,5 thousand people, while there were single cases of exposure in doses up to 100 R. Conclusion: the collective dose received during the accident and liquidation of its consequences in 1957 was about 820 000 person-R. Collective doses recorded in 1958 and 1959 amounted to 250 000 person-R and 54 000 person-R, respectively.Цель исследования: оценить радиационную обстановку на территории промплощадки ПО «Маяк», сформировавшуюся в результате аварии 1957 г., а также дозовые нагрузки на лиц, принимавших участие в ликвидации последствий этой аварии. Материалы и методы: на основании анализа архивных документов, данных журналов радиационной обстановки за 1957–1960 гг., картотеки индивидуального дозиметрического контроля и проведенных расчетов представлены материалы по измеренным и расчетным дозам облучения как работников ПО «Маяк», так и лиц сторонних организаций и воинских частей, привлеченных к ликвидации последствий аварии и охваченных индивидуальным контролем. Результаты: в работах по ликвидации последствий аварии на территории промышленной площадки ПО «Маяк» в 1957–1959 гг. приняли участие 38,5 тыс. человек, включая лиц, облученных непосредственно в момент аварии, а также работников ПО «Маяк», военных и гражданских строителей, принимавших участие в ликвидации последствий аварии. Дозы облучения от 25 до 30 Р получили около 10,5 тыс. человек, при этом имелись случаи облучения в дозах до 100 Р. Заключение: коллективная доза, полученная во время аварии и при ликвидации ее последствий в 1957–1959 гг., составила ≈820 тыс.чел.-Р, из них 457 тыс. чел.-Р за счет облучения военнослужащих и заключенных 10 лаготделения в момент и первые часы после аварии. Коллективные дозы, зарегистрированные в 4 квартале 1957 г., в 1958 и 1959 гг. у участников ликвидации последствий аварии составили 50 тыс.чел.-Р, 250 тыс.чел.-Р и 54 тыс.чел.-Р соответственно

Elucidating the mechanism of ferrocytochrome c heme disruption by peroxidized cardiolipin

The interaction of peroxidized cardiolipin with ferrocytochrome c induces two kinetically and chemically distinct processes. The first is a rapid oxidation of ferrocytochrome c, followed by a slower, irreversible disruption of heme c. The oxidation of ferrocytochrome c by peroxidized cardiolipin is explained by a Fenton-type reaction. Heme scission is a consequence of the radical-mediated reactions initiated by the interaction of ferric heme iron with peroxidized cardiolipin. Simultaneously with the heme c disruption, generation of hydroxyl radical is detected by EPR spectroscopy using the spin trapping technique. The resulting apocytochrome c sediments as a heterogeneous mixture of high aggregates, as judged by sedimentation analysis. Both the oxidative process and the destructive process were suppressed by nonionic detergents and/or high ionic strength. The mechanism for generating radicals and heme rupture is presented