1,035 research outputs found

    Multilevel Analysis of Oscillation Motions in Active Regions of the Sun

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    We present a new method that combines the results of an oscillation study made in optical and radio observations. The optical spectral measurements in photospheric and chromospheric lines of the line-of-sight velocity were carried out at the Sayan Solar Observatory. The radio maps of the Sun were obtained with the Nobeyama Radioheliograph at 1.76 cm. Radio sources associated with the sunspots were analyzed to study the oscillation processes in the chromosphere-corona transition region in the layer with magnetic field B=2000 G. A high level of instability of the oscillations in the optical and radio data was found. We used a wavelet analysis for the spectra. The best similarities of the spectra of oscillations obtained by the two methods were detected in the three-minute oscillations inside the sunspot umbra for the dates when the active regions were situated near the center of the solar disk. A comparison of the wavelet spectra for optical and radio observations showed a time delay of about 50 seconds of the radio results with respect to optical ones. This implies a MHD wave traveling upward inside the umbral magnetic tube of the sunspot. Besides three-minute and five-minute ones, oscillations with longer periods (8 and 15 minutes) were detected in optical and radio records.Comment: 17 pages, 9 figures, accepted to Solar Physics (18 Jan 2011). The final publication is available at http://www.springerlink.co

    Aerodynamic Modeling for Post-Stall Flight Simulation of a Transport Airplane

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    The file attached to this record is the author's final peer reviewed version.open access articleThe principles of aerodynamic modeling in the extended flight envelope, which is characterized by the development of separated flow, are outlined and illustrated for a generic transport airplane. The importance of different test techniques for generating wind tunnel data and the procedure for blending the obtained experimental data for aerodynamic modeling are discussed. Complementary use of computational fluid dynamics simulations reveals a substantial effect of the Reynolds number on the intensity of aerodynamic autorotation, which is later reflected in the aerodynamic model. Validation criteria for an extended envelope aerodynamic model are discussed, and the important role of professional test pilots with post-stall flying experience in tuning aerodynamic model parameters is emphasized. The paper presents an approach to aerodynamic modeling that was implemented in the project Simulation of Upset Recovery inAviation (2009–2012), funded by the EuropeanUnion under the seventh framework programme. The developed post-stall aerodynamic model of a generic airliner configuration for a wide range of angles of attack, sideslip, and angular rate was successfully validated by a number of professional test pilots on hexapod and centrifuge-based flight simulator platforms

    Investigation of using sulfur-containing gases in low-temperature fuel cell at sulfuric acid production site

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    The possibility and effectiveness of using sulfur dioxide and hydrogen sulfide as the fuel in lowtemperature fuel cells at the sulfuric acid production site has been investigated. A fuel cell has been designed and constructed using palladium as a catalyst, which enables conversion of the energy of oxidation of sulfur dioxide and hydrogen sulfide to the electric energy. The experimental data showed that the use of hydrogen sulfide and sulfur dioxide as a fuel allows achieving the power of 1.0 and 0.5 mW, respectively. The comparative studies with the use of hydrogen in the same fuel cell resulted in the power of about 2.0 mW, i.e. the use of hydrogen sulfide delivers a performance comparable with that of the hydrogen. The processes of oxidizing of the sulfur containing gases are used in our company in production of sulfuric acid. Oxidation of these gases conducted using the conventional technological processes. The use of these processes to produce energy as a byproduct could be an attractive way to reduce the energy consumption of the whole process. Considering the relatively high power obtained in this work for the sulfur containing gases fed fuel cells, the substitution of conventional oxidation of sulfur containing gases in this technological chain by the fuel cell oxidation, and by-producing the electric energy, could be very profitable for the energy efficiency enhancement of the main production process. In the future work, the design and development of fuel cell catalysts and membranes to enhance the performances of sulfur containing fuel cells will be significant

    Z3_3-graded differential geometry of quantum plane

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    In this work, the Z3_3-graded differential geometry of the quantum plane is constructed. The corresponding quantum Lie algebra and its Hopf algebra structure are obtained. The dual algebra, i.e. universal enveloping algebra of the quantum plane is explicitly constructed and an isomorphism between the quantum Lie algebra and the dual algebra is given.Comment: 17 page

    Proton Affinity in the Chemistry of Beta-Octamolybdate: HPLC-ICP-AES, NMR and Structural Studies

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    The affinity of [β-Mo8O26]4− toward different proton sources has been studied in various conditions. The proposed sites for proton coordination were highlighted with single crystal X-ray diffraction (SCXRD) analysis of (Bu4N)3[β-{Ag(py-NH2)Mo8O26]}] (1) and from analysis of reported structures. Structural rearrangement of [β-Mo8O26]4− as a direct response to protonation was studied in solution with 95Mo NMR and HPLC-ICP-AES techniques. A new type of proton transfer reaction between (Bu4N)4[β-Mo8O26] and (Bu4N)4H2[V10O28] in DMSO results in both polyoxometalates transformation into [V2Mo4O19]4−, which was confirmed by the 95Mo, 51V NMR and HPLC-ICP-AES techniques. The same type of reaction with [H4SiW12O40] in DMSO leads to metal redistribution with formation of [W2Mo4O19]2−. © 2022 by the authors.Council on grants of the President of the Russian Federation, (MD-396.2021.1.3)This work was supported by the grant of the President of the Russian Federation for young scientists—Doctors of Sciences MD-396.2021.1.3

    Design, performance, and calibration of the CMS hadron-outer calorimeter

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    The outer hadron calorimeter (HCAL HO) of the CMS detector is designed to measure the energy that is not contained by the barrel (HCAL HB) and electromagnetic (ECAL EB) calorimeters. Due to space limitation the barrel calorimeters do not contain completely the hadronic shower and an outer calorimeter (HO) was designed, constructed and inserted in the muon system of CMS to measure the energy leakage. Testing and calibration of the HO was carried out in a 300 GeV/c test beam that improved the linearity and resolution. HO will provide a net improvement in missing E T measurements at LHC energies. Information from HO will also be used for the muon trigger in CMS
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