121 research outputs found
The observed radio/gamma-ray emission correlation for blazars with the Fermi-LAT and the RATAN-600 data
We study the correlation between gamma-ray and radio band radiation for 123
blazars, using the Fermi-LAT first source catalog (1FGL) and the RATAN-600 data
obtained at the same period of time (within a few months). We found an apparent
positive correlation for BL Lac and flat-spectrum radio quasar (FSRQ) sources
from our sample through testing the value of the Pearson product-moment
correlation coefficient. The BL Lac objects show higher values of the
correlation coefficient than FSRQs at all frequencies, except 21.7 GHz, and at
all bands, except GeV, typically at high confidence level (> 99%). At
higher gamma-ray energies the correlation weakens and even becomes negative for
BL Lacs and FSRQs. For BL Lac blazars, the correlation of the fluxes appeared
to be more sensitive to the considered gamma-ray energy band, than to the
frequency, while for FSRQ sources the correlation changed notably both with the
considered radio frequency and gamma-ray energy band. We used a data
randomization method to quantify the significance of the computed correlation
coefficients. We find that the statistical significance of the correlations we
obtained between the flux densities at all frequencies and the photon flux in
all gamma-ray bands below 3 GeV is high for BL Lacs (chance probability ). The correlation coefficient is high and significant for
the GeV band and low and insignificant for the GeV band for
both types of blazars for all considered frequencies.Comment: 14 pages, 5 tables, 8 figures, accepted to MNRA
Schiaparelli\u27s Shooting Stars
The fundamental work on this translation was done by Miss Francis M. Svaldi, a student working on National Youth Administration funds. After Miss Svaldi\u27s graduation, her work was revised and corrected by James R. Naiden, Special Research Assistant in Astronomy (now 1st Lieutenant Army Air Corps), working under the direction of C. C. Wylie, Professor of Astronomy. The pressure of war work, and the enlistment of Mr. Naiden in the Armed Forces, have made it impossible to smooth out the translation as planned. However, it has been thought best to publish it in its present form, since it is not known when further work will be possible. The language of Schiaparelli is unusually full, and very precise. In this translation, such a precision would have appeared exaggerated, and an occasional word or phrase has been omitted to enhance clarity
Interview
An exploration of work by Liz Naiden in the form of a conversation discussing light and dark, attention and proprioception, and design and architectural theories of space in installation works. Addresses the role of voice, speech, and reading and speaking aloud, performing for oneself, and performing for others
The features of microstructure and mechanical properties of austenitic steel after direct and reverse martensitic transformations
The features of structural states of metastable austenitic steel after thermomechanical treatments, including low-temperature deformation, warm deformation and subsequent annealing are investigated. It is shown that under these conditions the direct (Ξ³ β Ξ±β²) and reverse (Ξ±β² β Ξ³) martensitic transformations occur and submicrocrystalline structural states are formed. The proposed thermomechanical treatment allows varying the strength and plastic properties of austenitic steel in a wide range. The strength of steel in submicrocrystalline state is 4β6 times higher than its original value
Effect of heat treatment on the structural parameters and magnetic properties of copper ferrite nanopowders obtained by the sol-gel combustion
Phase composition, structure parameters and basic magnetic characteristics obtained by the sol-gel combustion nanopowders of ferrospinel CuFe2O4 are investigated. A comparison of the properties of synthesized materials: first sample - immediately after the combustion of the gel and second sample - after annealing at 1073 K for 4 hours are performed. Annealing leads to an increase in the concentration of the phase with tetragonal crystal structure. Particle sizes and the value of anisotropy field of this phase also increased
Radiation-thermal synthesis of W-type hexaferrites
The results of investigations of the phase composition, structural parameters, static and dynamic magnetic properties of BaCo0.7Zn1.3Fe16O27 hexaferrites obtained by the method of self-propagation high-temperature synthesis in combination with mechanochemical activation and radiation-thermal post-sintering are presented. The prospects of the proposed energy-saving approach for the production of ferrite ceramics with a hexagonal structure is shown
STORAGE IMPACT ON THE QUALITY OF RASPBERRY AND PEACH JAMS
Abstract The aim of this study is to evaluate the quality properties of raspberry and peach jams during storage. Jams were prepared with a reduced amount of sucrose, citric acid and low-estrified pectin with the addition of calcium ions in the form of calcium citrate. Physico-chemical parameters, such as total dry matter, soluble solids, sugars, total acids, pH, vitamin C, fats, proteins and ash after storage of 15 and 90 days were tested. The jams were exposed to microbiological analysis also. Results showed that the values of ash, fats and vitamin C were not changed regardless the storage period of the analysed raspberry and peach jams. The period of storage increased the values of total dry matter from 44.97% to 45.86%, soluble solids from 40.17 Β°Brix to 41.5 Β°Brix and total acids from 1.47% to 1.49% in raspberry jam. In peach jam these results changed from 42% to 44.1%, from 41.92 Β°Brix to 42.9 Β°Brix, and from 0.92% to 0.97% respectively. Microbiological examinations indicate that jams are microbiologically proper according to standards. From the overall results it can be concluded that the storage period has effect on the prepared raspberry and peach jams, but their quality remains good and has maximum consumer acceptance
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