16,274 research outputs found
Formation of a rotating jet during the filament eruption on 10-11 April 2013
We analyze multi-wavelength and multi-viewpoint observations of a helically
twisted plasma jet formed during a confined filament eruption on 10-11 April
2013. Given a rather large scale event with its high spatial and temporal
resolution observations, it allows us to clearly understand some new physical
details about the formation and triggering mechanism of twisting jet. We
identify a pre-existing flux rope associated with a sinistral filament, which
was observed several days before the event. The confined eruption of the
filament within a null point topology, also known as an Eiffel tower (or
inverted-Y) magnetic field configuration results in the formation of a twisted
jet after the magnetic reconnection near a null point. The sign of helicity in
the jet is found to be the same as that of the sign of helicity in the
filament. Untwisting motion of the reconnected magnetic field lines gives rise
to the accelerating plasma along the jet axis. The event clearly shows the
twist injection from the pre-eruptive magnetic field to the jet.Comment: 14 pages, 12 figures, to appear in MNRA
North-South Distribution of Solar Flares during Cycle 23
In this paper, we investigate the spatial distribution of solar flares in the
northern and southern hemisphere of the Sun that occurred during the period
1996 to 2003. This period of investigation includes the ascending phase, the
maximum and part of descending phase of solar cycle 23. It is revealed that the
flare activity during this cycle is low compared to previous solar cycle,
indicating the violation of Gnevyshev-Ohl rule. The distribution of flares with
respect to heliographic latitudes shows a significant asymmetry between
northern and southern hemisphere which is maximum during the minimum phase of
the solar cycle. The present study indicates that the activity dominates the
northern hemisphere in general during the rising phase of the cycle
(1997-2000). The dominance of northern hemisphere is shifted towards the
southern hemisphere after the solar maximum in 2000 and remained there in the
successive years. Although the annual variations in the asymmetry time series
during cycle 23 are quite different from cycle 22, they are comparable to cycle
21.Comment: 6 pages, 2 figures, 1 table; Accepted for the publication in the
proceedings of international solar workshop held at ARIES, Nainital, India on
"Transient Phenomena on the Sun and Interplanetary Medium" in a special issue
of "Journal of Astrophysics and Astronomy (JAA)
() spectroscopy using Cornell potential
The mass spectra and decay properties of heavy quarkonia are computed in
nonrelativistic quark-antiquark Cornell potential model. We have employed the
numerical solution of Schr\"odinger equation to obtain their mass spectra using
only four parameters namely quark mass (, ) and confinement strength
(, ). The spin hyperfine, spin-orbit and tensor
components of the one gluon exchange interaction are computed perturbatively to
determine the mass spectra of excited , , and states. Digamma,
digluon and dilepton decays of these mesons are computed using the model
parameters and numerical wave functions. The predicted spectroscopy and decay
properties for quarkonia are found to be consistent with available experimental
observations and results from other theoretical models. We also compute mass
spectra and life time of the meson without additional parameters. The
computed electromagnetic transition widths of heavy quarkonia and mesons
are in tune with available experimental data and other theoretical approaches
Quality Comparison of Vegetables Dehydrated in Solar Drier and Electrical Oven
Ascorbic acid, sugars, dehydration ratio and moisture were determined in the vegetables dehydrated separately in solar drier and in electrical oven under similar conditions by standard methods. Vegetables examined were cabbage, cauliflower, tomato, radish, turnip, lahi, methi and palak. It was revealed that in each case, contents of ascorbic acid were higher in solar-dried vegetables in comparison to oven-dried stuffs. This finding indicated superiority of solar driers over electrical ovens, both in reference to quality of the dehydrated vegetables and its overall cost of operation
Geo-social-rbac: A location-based socially aware access control framework
The ubiquity of low-cost GPS-enabled mobile devices and the proliferation of online social networks have enabled the collection of rich geo-social information that includes the whereabouts of the users and their social connections. This information can be used to provide a rich set of access control policies that ensure that resources are utilized securely. Existing literature focuses on providing access control systems that control the access solely based on either the location of the users or their social connections. In this paper, we argue that a number of real-world applications demand an access control model that effectively captures both the geographic as well as the social dimensions of the users in a given location. We propose, Geo-social-RBAC, a new role based access control model that allows the inclusion of geo-social constraints as part of the access control policy. Our model, besides capturing the locations of a user requesting access and her social connections, includes geo-social cardinality constraints that dictate how many people related by a particular social relation need to be present in the required locations at the time of an access. The model also allows specification of geo-social and location trace constraints that may be used to dictate if an access needs to be granted or denied
Superconductivity in 2-2-3 system Y2Ba2Cu2O(8+delta)
Researchers synthesized a new high T(sub c) 2-2-3 superconductor Y2Ba2Cu3O(8+delta) by a special preparation technique and characterized it by ac-susceptibility measurements. Diamagnetism and Meissner effect sets in at low fields and superconducting transition onsets at 90 K. The systematic investigation of the real and imaginary components of ac-susceptibility as a function of temperature and applied ac magnetic field reveals that the magnetic behavior is that of a granular type superconductor
Synthesis and antimicrobial activity of some hybrid 2-aryl-4-(1-phenyl-3-(p-tolyl)-1H-pyrazol-4-yl)-2,3-dihydro-1H-benzo[b][1,4]diazepine derivatives
238-246Some new hybrid 2-aryl-4-(1-phenyl-3-(p-tolyl)-1H-pyrazol-4-yl)-2,3-dihydro-1H-benzo[b][1,4]diazepines have been synthesised which possessed the pyrazole and benzodiazepine heterocycles 2a-t. Antimicrobial evaluation of the synthesized compounds have been carried out against different strains of bacteria like E. coli, P. aeruginosa, S. aureus and S. pyogenes and fungal strains like C. albicans, A. niger and A. clavatus using serial dilution method. The newly synthesized compounds 2i, 2j, 2k, 2l, 2m, 2q and 2t have shown significant activity against the above mentioned strains. The reported compounds in the present paper are supported by IR, 1H and 13C NMR, and LC-MS spectral analysis
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