63 research outputs found
Катализаторы для процесса получения водородного топлива.
The copper-zinc-zirconium cemen-tcontaining catalysts for steam reforming of methanol were prepared. Their activity in the process of methanol steam reforming has been investigated. It has been shown that introduction of zirconium-containing component in the copper-zinc cementcontaining catalysts results in increasing of activity and efficiency in the methanol steam reforming process. The proposed systems may be used as catalysts for obtaining of hydrogen fuelСинтезированы медь-цинк-циркониевые цементсодержащие катализаторы процесса паровой конверсии метанола. Исследована их активность и показано, что введение циркониевого компонента в медь-цинковые цементсодержащие катализаторы приводит к увеличению активности и производительности в процессе паровой конверсии метанола. Сделан вывод, что предложенные системы могут использоваться в качестве катализаторов для получения водородного топлива
Исследование каталитических свойств цирконийалюмооксидных и цирконийалюмокальциевых материалов в процессе дегидратации метанола
The zirconium-aluminium oxide and zirconium-containing calcium aluminate materials of different composition were prepared. Their activity in the process of methanol dehydration was investigated. It was found that their activity depends on the acidic properties of the surface of the synthesized materials, which in turn is determined by the ratio of components. It was concluded that the proposed systems can be promising catalysts for obtaining dimethyl ether.Синтезированы цирконийалюмооксидные и цирконийалюмокальциевые материалы различного состава. Исследована активность синтезированных материалов в процессе дегидратации метанола. Установлено, что их активность зависит от кислотных свойств поверхности полученных образцов, что, в свою очередь, регулируется соотношением компонентов. Сделан вывод, что предложенные системы могут быть перспективными катализаторами получения диметилового эфира
Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. VIII: The Eighth Year (2015-2016)
Continuing the project described by Kato et al. (2009, arXiv:0905.1757), we
collected times of superhump maxima for 128 SU UMa-type dwarf novae observed
mainly during the 2015-2016 season and characterized these objects. The data
have improved the distribution of orbital periods, the relation between the
orbital period and the variation of superhumps, the relation between period
variations and the rebrightening type in WZ Sge-type objects. Coupled with new
measurements of mass ratios using growing stages of superhumps, we now have a
clearer and statistically greatly improved evolutionary path near the terminal
stage of evolution of cataclysmic variables. Three objects (V452 Cas, KK Tel,
ASASSN-15cl) appear to have slowly growing superhumps, which is proposed to
reflect the slow growth of the 3:1 resonance near the stability border.
ASASSN-15sl, ASASSN-15ux, SDSS J074859.55+312512.6 and CRTS J200331.3-284941
are newly identified eclipsing SU UMa-type (or WZ Sge-type) dwarf novae.
ASASSN-15cy has a short (~0.050 d) superhump period and appears to belong to EI
Psc-type objects with compact secondaries having an evolved core. ASASSN-15gn,
ASASSN-15hn, ASASSN-15kh and ASASSN-16bu are candidate period bouncers with
superhump periods longer than 0.06 d. We have newly obtained superhump periods
for 79 objects and 13 orbital periods, including periods from early superhumps.
In order that the future observations will be more astrophysically beneficial
and rewarding to observers, we propose guidelines how to organize observations
of various superoutbursts.Comment: 123 pages, 162 figures, 119 tables, accepted for publication in PASJ
(including supplementary information
Discovery of a young low-mass brown dwarf transiting a fast-rotating F-type star by the Galactic Plane eXoplanet (GPX) survey
We announce the discovery of GPX-1 b, a transiting brown dwarf with a mass of
and a radius of
, the first sub-stellar object discovered by the Galactic
Plane eXoplanet (GPX) survey. The brown dwarf transits a moderately bright (
= 12.3 mag) fast-rotating F-type star with a projected rotational velocity
km/s. We use the isochrone placement algorithm to
characterize the host star, which has effective temperature K,
mass , radius
and approximate age Gyr. GPX-1 b has an orbital period
of 1.75 d, and a transit depth of %. We describe the GPX
transit detection observations, subsequent photometric and
speckle-interferometric follow-up observations, and SOPHIE spectroscopic
measurements, which allowed us to establish the presence of a sub-stellar
object around the host star. GPX-1 was observed at 30-min integrations by TESS
in Sector 18, but the data is affected by blending with a 3.4 mag brighter star
42 arcsec away. GPX-1 b is one of about two dozen transiting brown dwarfs known
to date, with a mass close to the theoretical brown dwarf/gas giant planet mass
transition boundary. Since GPX-1 is a moderately bright and fast-rotating star,
it can be followed-up by the means of Doppler tomography.Comment: 13 pages, 13 figures, accepted to MNRAS in May 202
Discovery of a Young Low-Mass Brown Dwarf Transiting a Fast-Rotating F-Type Star by the Galactic Plane eXoplanet (GPX) Survey
We announce the discovery of GPX-1 b, a transiting brown dwarf with a mass of 19.7 ± 1.6 MJup and a radius of 1.47 ± 0.10 RJup, the first substellar object discovered by the Galactic Plane eXoplanet (GPX) survey. The brown dwarf transits a moderately bright (V = 12.3 mag) fast-rotating F-type star with a projected rotational velocity v sin i∗ = 40 ± 10 km s−1. We use the isochrone placement algorithm to characterize the host star, which has effective temperature 7000 ± 200 K, mass 1.68 ± 0.10 M☉, radius 1.56 ± 0.10 R☉, and approximate age 0.27-0.15+0.09 Gyr. GPX-1 b has an orbital period of -1.75 d and a transit depth of 0.90 ± 0.03 per cent. We describe the GPX transit detection observations, subsequent photometric and speckle-interferometric follow-up observations, and SOPHIE spectroscopic measurements, which allowed us to establish the presence of a substellar object around the host star. GPX-1 was observed at 30-min integrations by TESS in Sector 18, but the data are affected by blending with a 3.4 mag brighter star 42 arcsec away. GPX-1 b is one of about two dozen transiting brown dwarfs known to date, with a mass close to the theoretical brown dwarf/gas giant planet mass transition boundary. Since GPX-1 is a moderately bright and fast-rotating star, it can be followed-up by the means of the Doppler tomography. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.The authors would like to thank the anonymous reviewer for their time and attention. The constructive comments we received helped us to improve the quality of the paper. This research has made use of the Exoplanet Orbit Database, the Exoplanet Data Explorer at exoplanets.org, Extrasolar Planets Encyclopaedia at exoplanets.eu, and the NASA Exoplanet Archive, which is operated by the California Institute of Technology under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This research was made possible through the use of the AAVSO Photometric All-Sky Survey (APASS), funded by the Robert Martin Ayers Sciences Fund and NSF AST-1412587. This research made use of Aladin (Bonnarel et al. 2000). IRAF is distributed by the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation. This research made use of ASTROPY,3 a community-developed core PYTHON package for Astronomy (Astropy Collaboration 2013; Price-Whelan et al. 2018). We acknowledge the use of TESScut.MAST data from full frame time series images (FFI) collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes (MAST). Funding for the TESS mission is provided by NASA?s Science Mission directorate. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. PB thanks Bruce Gary, the XO survey, and the KELT survey for furthering his education in exoplanet research. AYB would like to thank Catarina Fernandes and Julien de Wit for helpful discussions about the system. Organization of the EXPANSION project (ES), follow-up campaign of the photometry observations, speckle-interferometry observations with 6-m telescope BTA were supported by the Russian Science Foundation grant 19-72-10023. The work of VK was supported by the Ministry of Science and Higher Education of the Russian Federation, topic no. FEUZ-0836-2020-0038. This work was partly supported by the Ministry of Science and High Education of the Russian Federation (project no. FZZE-2020-0024) and Irkutsk State University (project no. 111-14-306). This work was partially supported by the Ministry of Science and Higher Education of the Russian Federation (project nos. FEUZ-2020-0030 and 075-15-2020-780). TRAPPIST-North is a project funded by the University of Liege, in collaboration with Cadi Ayyad University of Marrakech (Morocco). EJ and MG are F.R.S.-FNRS Senior Research Associates. The research leading to these results has received funding from the ARC grant for Concerted Research Actions financed by the Federation Wallonia-Brussels and from the International Balzan Prize Foundation. TRAPPIST is funded by the Belgian National Fund for Scientific Research (Fond National de la Recherche Scientifique, FNRS) under the grant FRFC 2.5.594.09.F. EP acknowledges the Europlanet 2024 RI project funded by the European Union?s Horizon 2020 Framework Programme (grant agreement no. 871149). AB acknowledge the support from the Program of Development of Lomonosov Moscow State University (Leading Scientific School ’Physics of stars, relativistic objects and galaxies’). OB thanks TÜBİTAK National Observatory for a partial support in using the T100 telescope with the project number 19AT100-1346. ODSD is supported by Portuguese national funds through Fundação para a Ciência e Tecnologia (FCT) in the form of a work contract (DL 57/2016/CP1364/CT0004), institutional funds UIDB/04434/2020 and UIDP/04434/2020, and scientific projects funds PTDC/FIS-AST/28953/2017 and POCI-01-0145-FEDER-028953
Catalysts for obtaining hydrogen fuel
The copper-zinc-zirconium cemen-tcontaining catalysts for steam reforming of methanol were prepared. Their activity in the process of methanol steam reforming has been investigated. It has been shown that introduction of zirconium-containing component in the copper-zinc cementcontaining catalysts results in increasing of activity and efficiency in the methanol steam reforming process. The proposed systems may be used as catalysts for obtaining of hydrogen fue
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