Search

Your search keyword '"Kruglov, S."' showing total 602 results
Start Over Author "Kruglov, S." Language english
602 results on '"Kruglov, S."'

7. Magnetic black holes in 4D Einstein–Gauss–Bonnet massive gravity coupled to nonlinear electrodynamics.

Author

Paul, Prosenjit and Kruglov, S. I.

Subjects
*VACUUM polarization, *EINSTEIN-Gauss-Bonnet gravity, *PHASE transitions, *SPECIFIC heat, *COSMOLOGICAL constant
Abstract

We investigated Einstein–Gauss–Bonnet (EGB) 4D massive gravity coupled to nonlinear electrodynamics (NED) in an anti-de Sitter (AdS) background and found an exact magnetically charged black hole solution. The metric function was analyzed for different values of massive gravity parameters. The first law of black hole thermodynamics and generalized Smarr formula were verified, where we treated the cosmological constant as thermodynamic pressure. We defined vacuum polarization as the conjugate to NED parameter. To analyze the local stability of the black hole, we computed specific heat. We investigated the van der Waals-like/re-entrant phase transition of the black holes and estimated the critical points. We observed small black hole (SBH)/large black hole (LBH) and SBH/intermediate black hole (IBH)/LBH phase transitions. The Joule–Thomson coefficient, inversion, and isenthalpic curves were discussed. Finally, the minimum inversion temperature and the corresponding event horizon radius were obtained using numerical techniques. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

9. Extended phase space thermodynamics of magnetized black holes with nonlinear electrodynamics.

Author

Kruglov, S. I.

Subjects
*PHASE space, *BLACK holes, *THERMODYNAMICS, *GIBBS' free energy, *ELECTRODYNAMICS, *SECOND law of thermodynamics
Abstract

Einstein's gravity in AdS space coupled to nonlinear electrodynamics (NED) with two parameters is studied. We investigate magnetically charged black holes. The metric and mass functions and their asymptotic are obtained showing that black holes may have one or two horizons. Thermodynamics in extended phase space was studied and it was proven that the first law of black hole thermodynamics and the generalized Smarr relation hold. The magnetic potential and the vacuum polarization conjugated to coupling (NED parameter), are computed and depicted. We calculate the Gibbs free energy and heat capacity. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

13. Passenger train braking with the provision of a preset value of a margin factor on brake shoe pressing.

Author

Kruglov, S., Kovyrshin, S., Ivanov, P., and Korsun, A.

Subjects
*BRAKE systems, *PASSENGER trains, *AUTOMATIC control systems, *COMPUTER simulation, *SHOES
Abstract

The matter of increasing the efficiency in electro-pneumatic passenger train braking (minimizing the braking distance and the probability of train wheels jamming) with automatic sustaining the margin factor on braking is considered. The latter is the ratio of the actual wheel adhesion force to the braking force formed by the braking system on the wheel. The more this factor exceeds 1, the less is probability for wheels sliding. It is suggested to design an automatic braking operation system that would be able to progress through braking stages automatically or semi-automatically in such a manner that the actual margin factor on pressing the brake shoe would remain within the previously determined level. An algorithm for adjusting the pressure in brake cylinders was formed. Computer modeling have shown that, compared with conventional braking, the proposed automatic control system with a low probability of wheel jamming allows to reduce the train braking distance to 25-30%. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

22. Nonlinearly charged AdS black holes, extended phase space thermodynamics and Joule-Thomson expansion

Author

Kruglov, S. I.

Subjects
General Physics (physics.gen-ph), Physics - General Physics, FOS: Physical sciences, General Physics and Astronomy
Abstract

We study thermodynamics and phase transitions of magnetically charged by nonlinear electrodynamics (NED) Anti-de Sitter (AdS) black holes in an extended phase space. The cosmological constant is treated as a thermodynamic pressure whereas the black hole mass is considered such as the chemical enthalpy. The horizon thermodynamics of black holes shows an analogy with the Van der Waals liquid-gas system. We define a quantities which are conjugated to the parameter of NED and a magnetic charge. It is shown that the first law of thermodynamics and the generalized Smarr relation hold. The critical exponents are the same as in the Van der Waals system. The Joule--Thomson adiabatic expansion of NED-AdS black holes is investigated because of thermodynamic behavior of black holes. The Joule--Thomson coefficient, the inversion and isenthalpic curves are discussed. The minimum of inversion temperature and the corresponding event horizon radius are obtained., 30 pages, 11 figures, 1 table

Published
2022

26. Efficacy and Safety of Systemic and Locoregional Cisplatin Chronotherapy in Rats with Ovarian Carcinoma

Author

Kireeva G, Gubareva E, Maydin M, Osetnik V, Kruglov S, Panchenko A, Dorofeeva A, Tyndyk M, Fedoros E, and Anisimov V

Subjects
circadian rhythm, ovarian cancer, chronochemotherapy, proliferation, cisplatin, hyperthermic intraperitoneal chemoperfusion, Neoplasms. Tumors. Oncology. Including cancer and carcinogens, dna damage, hipec, RC254-282
Abstract

Galina Kireeva,1 Ekaterina Gubareva,1 Mikhail Maydin,1 Vladislav Osetnik,2 Stepan Kruglov,1 Andrey Panchenko,1 Anastasia Dorofeeva,1 Margarita Tyndyk,1 Elena Fedoros,1 Vladimir Anisimov1 1Department of Carcinogenesis and Aging, N.N. Petrov National Medical Research Center of Oncology, Saint-Petersburg, Russia; 2Surgical Department, Saint-Petersburg State University Hospital, Saint-Petersburg, RussiaCorrespondence: Galina KireevaDepartment of Carcinogenesis and Aging, N.N. Petrov National Medical Research Center of Oncology, Leningradskaya Str. 68. Pesochny, Saint-Petersburg, 197758, RussiaEmail galinakireyeva@mail.ruAim: Alterations in circadian rhythms caused by tumor growth are thought to be clinically relevant as they affect the prognosis and treatment response. We aimed to evaluate the chronotherapeutic approach in rats with ovarian cancer receiving cisplatin intravenously (IV) or with hyperthermic intraperitoneal chemoperfusion (HIPEC) and to assess daily variations in tumor and intestinal epithelium proliferation.Methods: In the pilot study, we used 12 intact rats and 12 rats with transplantable ovarian cancer, which were euthanized at ZT0 (08:00, lights on), ZT6, ZT12 and ZT18. In the main study, we used 45 rats with transplantable ovarian cancer. Animals were randomized into five groups: control, HIPEC with cisplatin at ZT0 (08:00), HIPEC with cisplatin at ZT12 (20:00), IV cisplatin at ZT0 and IV cisplatin at ZT12. We assessed the proliferation rate of tumor and small intestinal epithelium, apoptosis in small intestinal epithelium, and levels of γ-H2AX (DNA damage/repair marker) in kidneys and liver. Survival was calculated in each group.Results: Ascitic ovarian cancer disrupted daily variations in intestinal epithelium proliferation and DNA damage/repair in rats. Ovarian carcinoma exhibited no daily variation in mitotic activity. In animals receiving IV cisplatin, massive cell damage in the renal medulla and cystic changes within renal tubules were observed, unlike in rats receiving HIPEC. Tumor mitotic activity was lower in morning-treated groups. The median survival of rats in the control group was 8.5 days (95% CI 6.0– 22.0), in HIPEC at ZT0 40.5 days (95% CI 28.0– 47.0, p< 0.001) and in HIPEC at ZT12 32.0 days (95% CI 28.0– 37.0, p< 0.001).Conclusion: In a rat model, ovarian tumor growth disrupted daily variations in intestinal epithelium proliferation and caused genotoxic stress in tumor-free tissues. HIPEC with cisplatin at ZT0 had a better efficacy/toxicity profile than HIPEC with cisplatin at ZT12 and IV administration at both time points.Keywords: ovarian cancer, circadian rhythm, chronochemotherapy, cisplatin, hyperthermic intraperitoneal chemoperfusion, HIPEC, proliferation, DNA damage

Published
2021

27. Logarithmic gravity model.

Author

Kruglov, S. I.

Subjects
*EINSTEIN-Hilbert action, *DARK energy, *CURVATURE, *GRAVITY
Abstract

In this paper, the modified F (R) gravity theory with the function F (R) = − (1 / β) ln (1 − β R) is studied. The action at small coupling β becomes Einstein–Hilbert action. The bound on the parameter β from local tests is β ≤ 2 × 1 0 − 6 cm2. We find the constant curvature solutions and it was shown that the de Sitter space is unstable but a solution with zero Ricci scalar is stable. The potential and the mass of the scalar field (scalaron) are obtained in Einstein's frame. The slow-roll cosmological parameters are studied and e-folds number is evaluated. The critical points of autonomous equations are analyzed. The function m (r) that describes the deviation from the Λ CDM model is calculated. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

31. Helicity dependence of the γ 3He → πX reactions in the Δ(1232) resonance region

Author

Costanza, S., Mushkarenkov, A., Rigamonti, F., Romaniuk, M., Aguar Bartolomé, P., Ahrens, J., Annand, J. R. M., Arends, H. -J., Beck, R., Braghieri, A., Bekrenev, V., Berghäuser, H., Briscoe, W. J., Cherepnya, S. N., Collicott, C., Downie, E. J., Drexler, P., Fil’kov, L. V., Fix, A., Glazier, D. I., Hamilton, D., Heid, E., Heil, W., Hornidge, D., Howdle, D., Jaegle, I., Huber, G. M., Jahn, O., Jude, T., Kashevarov, V. L., Keshelashvili, I., Kondratiev, R., Korolija, M., Krimmer, J., Krusche, B., Kruglov, S., Kulbardis, A., Lisin, V., Livingston, K., MacGregor, I. J. D., Mancell, J., Mandaglio, G., Manley, D. M., McGeorge, J. C., Middleton, D. G., Metag, V., Nefkens, B. M. K., Nikolaev, A., Oberle, M., Ostrick, M., Ortega, H., Otte, P. B., Oussena, B., Pedroni, P., Pheron, F., Polonski, A., Prakhov, S., Rosner, G., Rostomyan, T., Sarty, A. J., Schumann, S., Starostin, A., Supek, I., Thiel, M., Thomas, A., Unverzagt, M., Watts, D. P., Werthmüller, D., and A2 Collaboration

Published
2014
Full Text
View/download PDF

32. Measurement of the beam-helicity asymmetry I⊙ in the photoproduction of $ \pi^{\pm}$ pairs off protons and off neutrons

Author

Oberle, M., Ahrens, J., Annand, J. R. M., Arends, H. J., Bantawa, K., Bartolome, P. A., Beck, R., Bekrenev, V., Berghäuser, H., Braghieri, A., Branford, D., Briscoe, W. J., Brudvik, J., Cherepnya, S., Demissie, B., Dieterle, M., Downie, E. J., Drexler, P., Fil’kov, L. V., Fix, A., Glazier, D. I., Heid, E., Hornidge, D., Howdle, D., Huber, G. M., Jahn, O., Jaegle, I., Jude, T. C., Käser, A., Kashevarov, V. L., Keshelashvili, I., Kondratiev, R., Korolija, M., Kruglov, S. P., Krusche, B., Kulbardis, A., Lisin, V., Livingston, K., MacGregor, I. J. D., Maghrbi, Y., Mancell, J., Manley, D. M., Marinides, Z., Martinez, M., McGeorge, J. C., McNicoll, E., Mekterovic, D., Metag, V., Micanovic, S., Middleton, D. G., Mushkarenkov, A., Nefkens, B. M. K., Nikolaev, A., Novotny, R., Ostrick, M., Oussena, B., Pedroni, P., Pheron, F., Polonski, A., Prakhov, S. N., Robinson, J., Rosner, G., Rostomyan, T., Schumann, S., Sikora, M. H., Sober, D. I., Starostin, A., Supek, I., Thiel, M., Thomas, A., Unverzagt, M., Watts, D. P., Werthmüller, D., Witthauer, L., Zehr, F., and The Crystal Ball at MAMI, TAPS and A2 Collaborations

Published
2014
Full Text
View/download PDF

33. Magnetic black holes in AdS space with nonlinear electrodynamics, extended phase space thermodynamics and Joule–Thomson expansion.

Author

Kruglov, S. I.

Subjects
*JOULE-Thomson effect, *PHASE space, *THERMODYNAMICS, *GIBBS' free energy, *FIRST law of thermodynamics, *ELECTRODYNAMICS
Abstract

This paper studies thermodynamics of magnetically charged black holes in Anti-de Sitter space in an extended phase space. The cosmological constant is considered as a pressure and the black hole mass is treated as the chemical enthalpy. The black hole thermodynamics is similar to the Van der Walls liquid–gas thermodynamics. Quantities conjugated to the nonlinear electrodynamics parameter and a magnetic charge are obtained. The first law of thermodynamics and the generalized Smarr relation take place. We investigate critical behavior of black holes and Joule–Thomson expansion. The Gibbs free energy, the Joule–Thomson coefficient and the inversion temperature are calculated. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

34. Quasi-free photoproduction of η-mesons off 3He nuclei

Author

Witthauer, L., Werthmüller, D., Keshelashvili, I., Aguar-Bartolomé, P., Ahrens, J., Annand, J. R. M., Arends, H. J., Bantawa, K., Beck, R., Bekrenev, V., Braghieri, A., Branford, D., Briscoe, W. J., Brudvik, J., Cherepnya, S., Demissie, B., Dieterle, M., Downie, E. J., Drexler, P., Fil’kov, L. V., Fix, A., Glazier, D. I., Hamilton, D., Heid, E., Hornidge, D., Howdle, D., Huber, G. M., Jaegle, I., Jahn, O., Jude, T. C., Käser, A., Kashevarov, V. L., Kondratiev, R., Korolija, M., Kruglov, S. P., Krusche, B., Kulbardis, A., Lisin, V., Livingston, K., MacGregor, I. J. D., Maghrbi, Y., Mancell, J., Manley, D. M., Marinides, Z., Martinez, M., McGeorge, J. C., McNicoll, E., Metag, V., Middleton, D. G., Mushkarenkov, A., Nefkens, B. M. K., Nikolaev, A., Novotny, R., Oberle, M., Ostrick, M., Oussena, B., Pedroni, P., Pheron, F., Polonski, A., Prakhov, S., Robinson, J., Rosner, G., Rost, M., Rostomyan, T., Schumann, S., Sikora, M. H., Sober, D., Starostin, A., Supek, I., Thiel, M., Thomas, A., Unverzagt, M., Watts, D. P., and Crystal Ball/TAPS experiment at MAMI, the A2 Collaboration

Published
2013
Full Text
View/download PDF

36. Einstein-Gauss-Bonnet gravity with nonlinear electrodynamics

Author

Kruglov, S. I.

Subjects
High Energy Physics - Theory, General Relativity and Quantum Cosmology, High Energy Physics - Theory (hep-th), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc)
Abstract

We obtain an exact spherically symmetric and magnetically charged black hole solution in 4D Einstein-Gauss-Bonnet gravity coupled with nonlinear electrodynamics with the Lagrangian ${\cal L}_{NED} = -{\cal F}/(1+\sqrt{2\mid\beta{\cal F}\mid})$ (${\cal F}$ is the field strength invariant). The thermodynamics of the black hole is studied within our model. We calculate the Hawking temperature and the heat capacity of the black hole. The phase transitions occur in the point where the Hawking temperature possesses an extremum and the heat capacity diverges. It was shown that black holes are thermodynamically stable in some range of event horizon radii when the heat capacity and Hawking temperature are positive. The logarithmic correction to the Bekenstein - Hawking BH entropy is obtained which mimics a quantum correction. The dependence of the BH shadow radius on the model parameters is studied. We also investigate the particle emission rate of the BH. The stability of the BH is studied by analysing the quasinormal modes., Comment: 25 pages, 8 figures, 3 tables, published in Annals of Physics

Published
2021

38. Measurements of 12C$E_{\gamma}=200$–450 MeV

Author

Robinson, J., MacGregor, I. J. D., Annand, J. R. M., Aguar-Bartolomé, P., Akasoy, L. K., Arends, H. J., Azimov, Ya. I., Bantawa, K., Beck, R., Bekrenev, V. S., Berghäuser, H., Braghieri, A., Branford, D., Briscoe, W. J., Brudvik, J., Cherepnya, S., Codling, R. F. B., Demissie, B. T., Dieterle, M., Downie, E. J., Drexler, P., Fil’kov, L. V., Glazier, D. I., Gregor, R., Hamilton, D., Heid, E., Hornidge, D., Howdle, D., Jahn, O., Jude, T. C., Kashevarov, V. L., Keshelashvili, I., Kondratiev, R., Korolija, M., Kotulla, M., Koulbardis, A. A., Kruglov, S. P., Krusche, B., Lisin, V., Livingston, K., Manley, D. M., McGeorge, J. C., McNicoll, E. F., Metag, V., Middleton, D. G., Mushkarenkov, A., Nefkens, B. M. K., Nikolaev, A., Novotny, R., Oberle, M., Ostrick, M., Owens, R. O., Otte, P. B., Oussena, B., Pedroni, P., Polonski, A., Prakhov, S., Rosner, G., Rostomyan, T., Schumann, S., Sikora, M. H., Sober, D. I., Starostin, A., Strakovsky, I. I., Suarez, I. M., Supek, I., Tarbert, C. M., Thiel, M., Thomas, A., Unverzagt, M., Watts, D. P., Werthmueller, D., Witthauer, L., and The Crystal Ball at MAMI and A2 Collaborations

Published
2013
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results