748 research outputs found
Dynamics of Pulsed Flow in an Elastic Tube
Internal haemorrhage, often leading to cardio-vascular arrest happens to be
one of the prime sources of high fatality rates in mammals. We propose a
simplistic model of fluid flow to specify the location of the haemorrhagic
spots, which, if located accurately, could be operated upon leading to a
possible cure. The model we employ for the purpose is inspired by fluid
mechanics and consists of a viscous fluid, pumped by a periodic force and
flowing through an elastic tube. The analogy is with that of blood, pumped from
the heart and flowing through an arte ry or vein. Our results, aided by
graphical illustrations, match reasonably well with experimental observations.Comment: 6 pages and 4 figure
Magneto-transport in a mesoscopic ring with Rashba and Dresselhaus spin-orbit interactions
Electronic transport in a one-dimensional mesoscopic ring threaded by a
magnetic flux is studied in presence of Rashba and Dresselhaus spin-orbit
interactions. A completely analytical technique within a tight-binding
formalism unveils the spin-split bands in presence of the spin-orbit
interactions and leads to a method of determining the strength of the
Dresselhaus interaction. In addition to this, the persistent currents for
ordered and disordered rings have been investigated numerically. It is observed
that, the presence of the spin-orbit interaction, in general, leads to an
enhanced amplitude of the persistent current. Numerical results corroborate the
respective analytical findings.Comment: 7 pages, 7 figure
Metal-insulator transition in an aperiodic ladder network: an exact result
We show, in a completely analytical way, that a tight binding ladder network
composed of atomic sites with on-site potentials distributed according to the
quasiperiodic Aubry model can exhibit a metal-insulator transition at multiple
values of the Fermi energy. For specific values of the first and second
neighbor electron hopping, the result is obtained exactly. With a more general
model, we calculate the two-terminal conductance numerically. The numerical
results corroborate the analytical findings and yield a richer variety of
spectrum showing multiple mobility edges.Comment: 4 pages, 3 figure
Chemical modeling for predicting the abundances of certain aldimines and amines in hot cores
We consider six isomeric groups (CH3N, CH5N, C2H5N, C2H7N, C3H7N and C3H9N)
to review the presence of amines and aldimines within the interstellar medium
(ISM). Each of these groups contains at least one aldimine or amine.
Methanimine (CH2NH) from CH3N and methylamine (CH3NH2) from CH5N isomeric group
were detected a few decades ago. Recently, the presence of ethanimine (CH3CHNH)
from C2H5N isomeric group has been discovered in the ISM. This prompted us to
investigate the possibility of detecting any aldimine or amine from the very
next three isomeric groups in this sequence: C2H7N, C3H7N and C3H9N. We employ
high-level quantum chemical calculations to estimate accurate energies of all
the species. According to enthalpies of formation, optimized energies, and
expected intensity ratio, we found that ethylamine (precursor of glycine) from
C2H7N isomeric group, (1Z)-1-propanimine from C3H7N isomeric group, and
trimethylamine from C3H9N isomeric group are the most viable candidates for the
future astronomical detection. Based on our quantum chemical calculations and
from other approximations (from prevailing similar types of reactions), a
complete set of reaction pathways to the synthesis of ethylamine and
(1Z)-1-propanimine is prepared. Moreover, a large gas-grain chemical model is
employed to study the presence of these species in the ISM. Our modeling
results suggest that ethylamine and (1Z)-1-propanimine could efficiently be
formed in hot-core regions and could be observed with present astronomical
facilities. Radiative transfer modeling is also implemented to additionally aid
their discovery in interstellar space.Comment: 32 pages, 18 Figures, Accepted for publication in the Astrophysical
Journa
Use of blue dust in sintering
Sintering studies were undertaken through a full factorial design of experi¬ment to estimate the quantitative effect of blue dust along with other process variables. Responses from the experiments were then correlated with the process variables through a regression equation. The coefficients of the equation indicated that the coke breeze exerted maximum influence on the strength. It was possible to incorporate blue dust to the extent of 40% with respect to total iron ore fraction without impairing the properties of sinter
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