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Search Results: 1 - 10 of 130401 matches for " V. Chubakov "
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U and Th content in the Central Apennines continental crust: a contribution to the determination of the geo-neutrinos flux at LNGS
M. Coltorti,R. Boraso,F. Mantovani,M. Morsilli,G. Fiorentini,A. Riva,G. Rusciadelli,R. Tassinari,C. Tomei,G. Di Carlo,V. Chubakov
Physics , 2011, DOI: 10.1016/j.gca.2011.01.024
Abstract: The regional contribution to the geo-neutrino signal at Gran Sasso National Laboratory (LNGS) was determined based on a detailed geological, geochemical and geophysical study of the region. U and Th abundances of more than 50 samples representative of the main lithotypes belonging to the Mesozoic and Cenozoic sedimentary cover were analyzed. Sedimentary rocks were grouped into four main "Reservoirs" based on similar paleogeographic conditions and mineralogy. Basement rocks do not outcrop in the area. Thus U and Th in the Upper and Lower Crust of Valsugana and Ivrea-Verbano areas were analyzed. Based on geological and geophysical properties, relative abundances of the various reservoirs were calculated and used to obtain the weighted U and Th abundances for each of the three geological layers (Sedimentary Cover, Upper and Lower Crust). Using the available seismic profile as well as the stratigraphic records from a number of exploration wells, a 3D modelling was developed over an area of 2^{\circ}x2^{\circ} down to the Moho depth, for a total volume of about 1.2x10^6 km^3. This model allowed us to determine the volume of the various geological layers and eventually integrate the Th and U contents of the whole crust beneath LNGS. On this base the local contribution to the geo-neutrino flux (S) was calculated and added to the contribution given by the rest of the world, yielding a Refined Reference Model prediction for the geo-neutrino signal in the Borexino detector at LNGS: S(U) = (28.7 \pm 3.9) TNU and S(Th) = (7.5 \pm 1.0) TNU. An excess over the total flux of about 4 TNU was previously obtained by Mantovani et al. (2004) who calculated, based on general worldwide assumptions, a signal of 40.5 TNU. The considerable thickness of the sedimentary rocks, almost predominantly represented by U- and Th- poor carbonatic rocks in the area near LNGS, is responsible for this difference.
Efficiency of photodesorption of Rb atoms collected on polymer organic film in vapor-cell
Sergey N. Atutov,Viacheslav P. Chubakov,Pavel A. Chubakov,Alexander I. Plekhanov
Physics , 2010, DOI: 10.1140/epjd/e2011-10382-3
Abstract: The efficiency of photodesorption of Rb atoms previously collected on polymer organic film has been studied in detail. This study was carried out in a Pyrex glass cell of which the inner surface was covered with (poly)dimethylsiloxane (PDMS) film and illuminated by a powerful flash lamp. The desorption dynamic of the Rb atoms density in the cell caused by the illumination and percentage of desorbed atoms was studied by using of Rb resonance lamp and free running diode laser as sources of probing light. It was determined that 85 percent collected chemical active Rb atoms and stored during 16 seconds in the closed cell, 75 percent in the pumped cell can be desorbed by single flash of the lamp. The number of stored atoms decays with a characteristic time of 60 min in isolated cell and with a time 12.4 minutes in a pumped cell. We believe that this efficient method of collection and fast realization of atoms or molecules could be used for enhancement of sensitivity of existed sensors for the trace detection of various elements (including toxic or radioactive ones) which is important to environmental applications, medicine or in geology. The effect might help to construct an efficient light-driven atomic source for a magneto-optical trap in a case of extremely low vapor density or very weak flux of atoms, such as artificial radioactive alkali atoms.
A reference Earth model for the heat producing elements and associated geoneutrino flux
Yu Huang,Viacheslav Chubakov,Fabio Mantovani,Roberta L. Rudnick,William F. McDonough
Physics , 2013,
Abstract: The recent geoneutrino experimental results from KamLAND and Borexino detectors reveal the usefulness of analyzing the Earth geoneutrino flux, as it provides a constraint on the strength of the radiogenic heat power and this, in turn, provides a test of compositional models of the bulk silicate Earth (BSE). This flux is dependent on the amount and distribution of heat producing elements (HPEs: U, Th and K) in the Earth interior. We have developed a geophysically-based, three-dimensional global reference model for the abundances and distributions of HPEs in the BSE. The structure and composition of the outermost portion of the Earth, the crust and underlying lithospheric mantle, is detailed in the reference model, this portion of the Earth has the greatest influence on the geoneutrino fluxes. The reference model combines three existing geophysical models of the global crust and yields an average crustal thickness of 34.4+-4.1 km in the continents and 8.0+-2.7 km in the oceans. In situ seismic velocity provided by CRUST 2.0 allows us to estimate the average composition of the deep continental crust by using new and updated compositional databases for amphibolite and granulite facies rocks in combination with laboratory ultrasonic velocities measurements. An updated xenolithic peridotite database is used to represent the average composition of continental lithospheric mantle. Monte Carlo simulation is used to predict the geoneutrino flux at 16 selected locations and to track the asymmetrical uncertainties of radiogenic heat power due to the log-normal distributions of HPE concentrations in crustal rocks.
Highly sensitive ammonia sensor using reflection of light at a glass - photonic crystal interface
A. S. Kuchyanov,P. A. Chubakov,H. Spisser,A. I. Plekhanov
Physics , 2013,
Abstract: We have discovered and studied the effect of the asymmetric deformation of a photonic crystal in the form of a change in the slope of the crystal planes as it is filled with a gaseous analyte. We have demonstrated that the use of a new effect leading to the displacement of the stop band against the unchanged spectrum of diffracted white light at the (glass-thin opal film) interface can be used as fast, compact, high sensitive and reproducible optical chemical sensor for ammonia. Low cost and simplicity of sensor fabrication, the response of which can be easily observed without resorting to spectral instruments are therefore likely to be attractive. The basis for high sensitivity (1 ppm), fast response (120 ms) is capillary vapor condensation. On the basis of this effect a cheap high-speed and highly sensitive gas sensors has been built.
Lifetime measurements of 214Po and 212Po with the CTF liquid scintillator detector at LNGS
Borexino Collaboration,G. Bellini,J. Benziger,D. Bick,G. Bonfini,D. Bravo,M. Buizza Avanzini,B. Caccianiga,L. Cadonati,F. Calaprice,C. Carraro,P. Cavalcante,A. Chavarria,A. Chepurnov,V. Chubakov,D. D'Angelo,S. Davini,A. Derbin,A. Etenko,K. Fomenko,D. Franco,C. Galbiati,S. Gazzana,C. Ghiano,M. Giammarchi,M. G?ger-Neff,A. Goretti,L. Grandi,E. Guardincerri,S. Hardy,Aldo Ianni,Andrea Ianni,V. Kobychev,D. Korablev,G. Korga,Y. Koshio,D. Kryn,M. Laubenstein,T. Lewke,Marcello Lissia,E. Litvinovich,B. Loer,F. Lombardi,P. Lombardi,L. Ludhova,I. Machulin,S. Manecki,W. Maneschg,G. Manuzio,Q. Meindl,E. Meroni,L. Miramonti,M. Misiaszek,D. Montanari,P. Mosteiro,F. Mantovani,V. Muratova,S. Nisi,L. Oberauer,M. Obolensky,F. Ortica,K. Otis,M. Pallavicini,L. Papp,L. Perasso,S. Perasso,A. Pocar,G. Ranucci,A. Razeto,A. Re,A. Romani,N. Rossi,A. Sabelnikov,R. Saldanha,C. Salvo,S. Sch?nert,H. Simgen,M. Skorokhvatov,O. Smirnov,A. Sotnikov,S. Sukhotin,Y. Suvorov,R. Tartaglia,G. Testera,R. B. Vogelaar,F. von Feilitzsch,J. Winter,M. Wojcik,A. Wright,M. Wurm,G. Xhixha,J. Xu,O. Zaimidoroga,S. Zavatarelli,G. Zuzel
Statistics , 2012,
Abstract: We have studied the alpha decays of 214Po into 210Pb and of 212Po into 208Pb tagged by the coincidence with the preceding beta decays from 214Bi and 212Bi, respectively. The employed 222Rn, 232Th, and 220Rn sources were sealed inside quartz vials and inserted in the Counting Test Facility at the underground Gran Sasso National Laboratory in Italy. We find that the mean lifetime of 214Po is (236.00 +- 0.42(stat) +- 0.15(syst)) \mu s and that of 212Po is (425.1 +- 0.9(stat) +- 1.2(syst)) ns. Our results, obtained from data with signal-to-background ratio larger than 1000, reduce the overall uncertainties and are compatible with previous measurements.
Nonsmooth Optimization Algorithms in Some Problems of Fracture Dynamics  [PDF]
V. V. Zozulya
Intelligent Information Management (IIM) , 2010, DOI: 10.4236/iim.2010.211073
Abstract: Mathematical statement of elastodynamic contact problem for cracked body with considering unilateral restrictions and friction of the crack faces is done in classical and weak forms. Different variational formulations of unilateral contact problems with friction based on boundary variational principle are considered. Nonsmooth optimization algorithms of Udzawa’s type for solution of unilateral contact problem with friction have been developed. Convergence of the proposed algorithms has been studied numerically.
Precessing Ball Solitons as Self-Organizing Systems during a Phase Transition in a Ferromagnet  [PDF]
V. V. Nietz
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.410A3010
Abstract:

Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition is induced by a magnetic field directed along the axis of anisotropy, while the action of the periodic field perpendicular to the main magnetic field has been analyzed. Under these conditions, the characteristics of arising equilibrium PBS are uniquely determined by the frequency of the periodic field, but the solitons with other frequencies are impossible. For such structure, the entropy increase connected with dissipation is compensated by the decrease of the entropy due to the external periodic field. It is shown that the equilibrium PBS are essentially the “self-organizing systems” that can arise spotaneously in a metastable state of ferromagnet.

Movement of Self-Organizing Solitons in Ferromagnet  [PDF]
V. V. Nietz
Applied Mathematics (AM) , 2015, DOI: 10.4236/am.2015.610155
Abstract: Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition induced by a magnetic field directed along the axis of anisotropy, while the additional action of high-frequency field perpendicular to the main magnetic field, are analyzed. It is shown that the spatial motion of solitons, associated with thermal fluctuations in the crystal, does not destroy the equilibrium of self-organized PBS.
Lα Line of Dark Positronium as a Nongravitational Detection of DM  [PDF]
V. Burdyuzha, V. Charugin
Journal of Modern Physics (JMP) , 2015, DOI: 10.4236/jmp.2015.613187
Abstract: An attempt to predict the new atomic dark matter lines is done on the example of a dark lepton atom-positronium. Its Layman-alpha line with the energy near 3 GeV may be observable if the appropriate conditions are realized. For this we have studied a γ-ray excess in the center of our galaxy. In principle, this excess may be produced by the Lα line of a dark positronium in the medium with Compton scattering. The possibility of observations of an annihilation line (E~300 TeV) of dark positronium is also predicted. Other proposals to observe the atomic dark matter are shortly described. Besides, Hα line (1.3μ) of usual positronum must be observable in the direction on the center of our galaxy.
Randomization of Energy and Momentum in Statistical Mechanics  [PDF]
V. V. Paranjape
Journal of Modern Physics (JMP) , 2015, DOI: 10.4236/jmp.2015.615223
Abstract: Particle-particle collisions in materials give rise to a particle distribution in energy and momentum in such a way that a most probable distribution is realized. I will show that an evaporating liquid generates a molecular imbalance in the equilibrium energy distribution. The molecular collisions by their inherent nature are able to repair the imbalance and in so doing it is shown that the liquids cool down. Similarly an external electric field creates substantial imbalance in the momentum distribution for the electrons in ionic semiconductors. Electron-electron collisions are able to restore the imbalance and as a consequence, similar to the evaporating liquid, the electron gas loses thermal energy and cools down.
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