22 research outputs found
Galactic and Extragalactic Samples of Supernova Remnants: How They Are Identified and What They Tell Us
Supernova remnants (SNRs) arise from the interaction between the ejecta of a
supernova (SN) explosion and the surrounding circumstellar and interstellar
medium. Some SNRs, mostly nearby SNRs, can be studied in great detail. However,
to understand SNRs as a whole, large samples of SNRs must be assembled and
studied. Here, we describe the radio, optical, and X-ray techniques which have
been used to identify and characterize almost 300 Galactic SNRs and more than
1200 extragalactic SNRs. We then discuss which types of SNRs are being found
and which are not. We examine the degree to which the luminosity functions,
surface-brightness distributions and multi-wavelength comparisons of the
samples can be interpreted to determine the class properties of SNRs and
describe efforts to establish the type of SN explosion associated with a SNR.
We conclude that in order to better understand the class properties of SNRs, it
is more important to study (and obtain additional data on) the SNRs in galaxies
with extant samples at multiple wavelength bands than it is to obtain samples
of SNRs in other galaxiesComment: Final 2016 draft of a chapter in "Handbook of Supernovae" edited by
Athem W. Alsabti and Paul Murdin. Final version available at
https://doi.org/10.1007/978-3-319-20794-0_90-
The effect of reversing current on the properties of copper and electrolytic copper powder. I. The morphology of powder particles
The selective dissolution of copper dendrites during electrodeposition by reversing current was discussed and the effects on the morphology of copper powder particles were elucidated
Electrodeposition of silver from nitrate solution: Part II. Mechanism of the effect of phosphate ions
The mechanism of compact Ag-film formation by electrolysis from nitrate solution with addition of small amounts of phosphate ions is elucidated. It is shown that the phosphate ions exert their effect by lowering the exchange current density. Consequently, the radii of nucleation exclusion zones also diminishes, thus producing conditions stimulating electrodeposition of continuous thin Ag-film
The preferred orientation of bright copper deposits
The preferred orientations of copper deposits obtained from acid sulfate solutions were examined. Mat deposits obtained in the absence of the additives and in the presence of disodium 2-naphthol-3,6-disulfonic acid possessed a weak (200) and (220) preferred orientation, respectively. Bright deposit obtained with thiourea only had (111)orientation, while the deposit obtained with mixture thiourea/disodium 2-naphthol-3,6-disulfonic acid exhibited predominant (111) orientation. Bright copper deposits had the preferred orientation in the closest-packed plane of f.c.c. copper lattice, i.e. in the (111)plane
Characterization of copper powder particles obtained by electrodeposition as function of different current densities
Morphology, internal structure and growth mechanism of electrodeposited Ni and Co powders
Kinetics of thermally activated processes in cordierite-based ceramics
Thermally activated processes in cordierite-based ceramics were investigated to determine the effect of the mechanical activation and the addition of TeO2 on kinetic and thermodynamic parameters of these processes. Using a combination of dilatometry and DTA measurements in the 100–1400 °C temperature range, it was established that both the mechanical activation and the addition of TeO2 have a significant effect on processes in cordierite-based ceramics. A combination of 5 mass% addition of TeO2 and mechanical activation for 40 min reduced the sintering temperature of cordierite ceramics to around 1100 °C. In addition, the analysis of DTA measurements of mechanically activated samples indicates that the mechanical activation leads to intensification of the cordierite formation through an increase in concentration of surface defects and an increase in grain contact surface in the initial powder.Peer-reviewed manuscript: [http://aspace.agrif.bg.ac.rs/handle/123456789/5733
Estimating the salt tolerance level of Brassica juncea B-85 (Seeta) variety by physiological and biochemical analysis
Phytoplasma diseases of medicinal crops
Phytoplasma diseases of medicinal plants occur worldwide and are of great
concern. So far 19 different phytoplasma ribosomal groups encompassing various
subgroups have been reported. The subgroup 16SrI-B phytoplasmas are the prevalent
agents mainly detected in Europe, North America and Asia. Phytoplasma diseases of
medicinal plants severely reduce yield and quality of crops along with the longevity
of the plants. Changes in the composition of secondary metabolites are induced, while
the levels of valuable phytochemicals are greatly affected. In contrast, an accumulation
of pharmaceutically important compounds such as vinblastine and vincristine is
reported in periwinkle upon phytoplasma infections. Important phytoplasma diseases
of several medicinal plants with special reference to their impact on active biological
constituents and secondary metabolites are reviewed. General information on geographic
distribution, diagnostics, genetic diversity, natural transmission and management
aspects of phytoplasmas infecting medicinal plants are also discussed