The Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite has been providing global observations of the ozone layer and key atmospheric pollutant gases, such as nitrogen dioxide (NO2) and ...sulfur dioxide (SO2), since October 2004. The data products from the same instrument provide consistent spatial and temporal coverage and permit the study of anthropogenic and natural emissions on local-to-global scales. In this paper, we examine changes in SO2 and NO2 over some of the world's most polluted industrialized regions during the first decade of OMI observations. In terms of regional pollution changes, we see both upward and downward trends, sometimes in opposite directions for NO2 and SO2, for different study areas. The trends are, for the most part, associated with economic and/or technological changes in energy use, as well as regional regulatory policies. Over the eastern US, both NO2 and SO2 levels decreased dramatically from 2005 to 2015, by more than 40 and 80 percent, respectively, as a result of both technological improvements and stricter regulations of emissions. OMI confirmed large reductions in SO2 over eastern Europe's largest coal-fired power plants after installation of flue gas desulfurization devices. The North China Plain has the world's most severe SO2 pollution, but a decreasing trend has been observed since 2011, with about a 50 percent reduction in 2012-2015, due to an economic slowdown and government efforts to restrain emissions from the power and industrial sectors. In contrast, India's SO2 and NO2 levels from coal power plants and smelters are growing at a fast pace, increasing by more than 100 and 50 percent, respectively, from 2005 to 2015. Several SO2 hot spots observed over the Persian Gulf are probably related to oil and gas operations and indicate a possible underestimation of emissions from these sources in bottom-up emission inventories. Overall, OMI observations have proved valuable in documenting rapid changes in air quality over different parts of the world during last decade. The baseline established during the first 11 years of OMI is indispensable for the interpretation of air quality measurements from current and future satellite atmospheric composition missions.
The spectra and kinetics of selective and continuum thermodynamically equilibrium emission of electromagnetic radiation from Er
2
O
3
microcrystals and a ruby single crystal in the visible and ...near-IR spectral regions under laser–thermal excitation by electric-discharge CO
2
lasers at a wavelength λ = 10.6 µm in the cw and pulsed modes have been experimentally investigated. The effect of the delay of continuum emission fronts and intensity peaks relative to laser pulses is explained by the difference in the temperatures of the heated layer and electromagnetic radiation. The delay time of the electromagnetic emission maximum is the characteristic time for establishing thermal equilibrium.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
An explanation is proposed for the anomalous spin-flop in antiferromagnetic Cu(pz)
2
(ClO
4
)
2
. Due to the closeness of the monoclinic and tetrahedral lattices, the spin-flop in a small magnetic ...field can be accompanied by a transition from one to another antiferromagnetic vector. These two vectors transform into each other under the action of symmetry elements lost during monoclinic lattice distortions.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
4.
The Version 3 OMI NO2 Standard Product Krotkov, Nickolay A.; Lamsal, Lok N.; Celarier, Edward A. ...
Atmospheric measurement techniques,
09/2017, Volume:
10, Issue:
9
Journal Article
Peer reviewed
Open access
We describe the new version 3.0 NASA Ozone Monitoring Instrument (OMI) standard nitrogen dioxide (NO2) products (SPv3). The products and documentation are publicly available from the NASA Goddard ...Earth Sciences Data and Information Services Center (https://disc.gsfc.nasa.gov/datasets/OMNO2_V003/summary/). The major improvements include (1) a new spectral fitting algorithm for NO2 slant column density (SCD) retrieval and (2) higher-resolution (1° latitude and 1.25° longitude) a priori NO2 and temperature profiles from the Global Modeling Initiative (GMI) chemistry–transport model with yearly varying emissions to calculate air mass factors (AMFs) required to convert SCDs into vertical column densities (VCDs). The new SCDs are systematically lower (by ∼10-40%) than previous, version 2, estimates. Most of this reduction in SCDs is propagated into stratospheric VCDs. Tropospheric NO2 VCDs are also reduced over polluted areas, especially over western Europe, the eastern US, and eastern China. Initial evaluation over unpolluted areas shows that the new SPv3 products agree better with independent satellite- and ground-based Fourier transform infrared (FTIR) measurements. However, further evaluation of tropospheric VCDs is needed over polluted areas, where the increased spatial resolution and more refined AMF estimates may lead to better characterization of pollution hot spots.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Kinetics of continual thermal emission spectra of Er
2
O
3
polycrystals is experimentally studied at laser-thermal excitation by single submicrosecond CO
2
laser pulses at λ = 10.6 µm. The nature and ...kinetics of Er
2
O
3
and other oxides are explained by the conversion of the thermal energy of the crystal lattice into continual Plank’s radiation. The results can be used for investigations of the energy balance of thermophotovoltaic electric converters with silicon, cascade, and hybrid photocells with laser-thermal and gas-flame heating of transparent pure and doped oxides up to melting temperatures as continual emitters.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
6.
Precritical Thermoacoustics in Helium Keshishev, K. O.; Marchenko, V. I.; Podolyak, E. R.
Journal of experimental and theoretical physics,
12/2021, Volume:
133, Issue:
6
Journal Article
Peer reviewed
Evolution of the fundamental mode of acoustic oscillations in a cavity filled with gaseous helium has been studied during immersion of this resonator into a helium transport Dewar vessel. Critical ...behavior of the parameter of oscillation decay has been observed on approaching the level below which thermoacoustic instability arises.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Spectra of thermal emission in polycrystalline Yb
2
O
3
, Eu
2
O
3
, ruby, and sapphire at resonant laser, laser-thermal, and gas-kinetic excitation are experimentally studied. Spectra of oxides in ...the visible and near IR regions are superposition of selective and continual spectra. Intensity of selective spectra at transitions between thermally populated electron-vibrational states of the structure and impurity ions is determined by the relation between radiative and nonradiative relaxation. It is found out that continual emission is not related to the chemical composition and micro- and electron structure of the investigated materials, and the temperature dependence of the spectra under thermodynamic equilibrium is described by the Planck function. The results are important for understanding the nature of thermal emission of oxides and for thermometry of hypersonic aerodynamic and thermophotovoltaic materials under extreme conditions.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Here we present an analysis of the X-ray morphology and flux variability of the particularly bright and extended western hotspot in the nearest powerful (FR II-type) radio galaxy, Pictor A, based on ...data obtained with the Chandra X-ray Observatory. The hotspot marks the position where the relativistic jet, which originates in the active nucleus of the system, interacts with the intergalactic medium, at hundreds-of-kiloparsec distances from the host galaxy, forming a termination shock that converts jet bulk kinetic energy to internal energy of the plasma. The hotspot is bright in X-rays due to the synchrotron emission of electrons accelerated to ultrarelativistic energies at the shock front. In our analysis, we make use of several Chandra observations targeting the hotspot over the last decades with various exposures and off-axis angles. For each pointing, we study in detail the point-spread function, which allows us to perform the image deconvolution, and to resolve the hotspot structure. In particular, the brightest segment of the X-ray hotspot is observed to be extended in the direction perpendicular to the jet, forming a thin, ∼3 kpc long, feature that we identify with the front of the reverse shock. The position of this feature agrees well with the position of the optical intensity peak of the hotspot, but is clearly offset from the position of the radio intensity peak, located ∼1 kpc further downstream. In addition, we measure the net count rate on the deconvolved images, finding a gradual flux decrease by about 30% over the 15 yr timescale of the monitoring.
ABSTRACT
The main idea of our research is to estimate the physical coalescence time of the double supermassive black hole (SMBH) system in the centre of NGC 6240 based on the X-ray observations from ...the Chandra space observatory. The spectra of the northern and southern nuclei were fitted by spectral models from Sherpa and both presented the narrow component of the Fe Kα emission line. It enabled us to apply the spectral model to these lines and to find relative offset ≈0.02 keV. The enclosed dynamical mass of the central region of NGC 6240 with radius 1 kpc was estimated $\approx 2.04\times 10^{11} \rm \,\, M_{\odot }$. These data allowed us to carry on the high-resolution direct N-body simulations with Newtonian and post-Newtonian (up to $2.5\mathcal {PN}$ correction) dynamics for this particular double SMBH system. As a result, from our numerical models, we approximated the central SMBH binary merging time for the different binary eccentricities. In our numerical parameters range, the upper limit for the merging time, even for the very small eccentricities, is still below ≈70 Myr. Gravitational waveforms and amplitude-frequency pictures from such events can be detected using pulsar timing array projects at the last merging phase.
The paper presents a procedure for determining the design parameters of multilayer thick-walled structures with a local load on the inner surface portion located near the end face. The design ...provides for the use of two layers, of which the outer layer can have a smaller height. The procedure involves obtaining numerical results of calculating the stress state of the inner cylinder, their approximation, the use of the Lame–Gadolin solution for shroud design. In the computational scheme for the first cylinder, the internal and external load intensities were taken to be constant. The result of the research is analytical relations relating the inner-to-outer radius ratios of the cylinder and shroud height to their strength characteristics. The use of these relations makes it possible to optimize the design. Numerical results obtained in the approximation and optimization of the design are presented.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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