8,178 research outputs found
Coupling of DEM and remote-sensing-based approaches for semi-automated detection of regional geostructural features in Zagros mountain, Iran.
In recent years, remote-sensing data have increasingly been used for the interpretation of objects and mapping in various applications of engineering geology. Digital elevation model (DEM) is very useful for detection, delineation, and interpretation of geological and structural features. The use of image elements for interpretation is a common method to extract structural features. In this paper, linear features were extracted from the Landsat ETM satellite image and then DEM was used to enhance those objects using digital-image-processing filtering techniques. The extraction procedures of the linear objects are performed in a semi-automated way. Photographic elements and geotechnical elements are used as main keys to extract the information from the satellite image data. This paper emphasizes on the application of DEM and usage of various filtering techniques with different convolution kernel size applied on the DEM. Additionally, this paper discusses about the usefulness of DEM and satellite digital data for extraction of structural features in SW of Zagros mountain, Iran
Ion transport through confined ion channels in the presence of immobile charges
We study charge transport in an ionic solution in a confined nanoscale
geometry in the presence of an externally applied electric field and immobile
background charges. For a range of parameters, the ion current shows
non-monotonic behavior as a function of the external ion concentration. For
small applied electric field, the ion transport can be understood from simple
analytic arguments, which are supported by Monte Carlo simulation. The results
qualitatively explain measurements of ion current seen in a recent experiment
on ion transport through a DNA-threaded nanopore (D. J. Bonthuis et. al., Phys.
Rev. Lett, vol. 97, 128104 (2006)).Comment: 5 pages, 3 figure
String Cosmology in Anisotropic Bianchi-II Space-time
The present study deals with a spatially homogeneous and anisotropic
Bianchi-II cosmological model representing massive strings. The energy-momentum
tensor, as formulated by Letelier (1983), has been used to construct a massive
string cosmological model for which the expansion scalar is proportional to one
of the components of shear tensor. The Einstein's field equations have been
solved by applying a variation law for generalized Hubble's parameter that
yields a constant value of deceleration parameter in Bianchi-II space-time. A
comparative study of accelerating and decelerating modes of the evolution of
universe has been carried out in the presence of string scenario. The study
reveals that massive strings dominate the early Universe. The strings
eventually disappear from the Universe for sufficiently large times, which is
in agreement with the current astronomical observations.Comment: 11 pages, 6 figures (To appear in Mod. Phys. Lett. A) In this
version, the cosmic string has been directed along z-direction and the
resultant field equations have been solved exactl
Is 4U 0114+65 an eclipsing HMXB?
We present the pulsation and spectral characteristics of the HMXB 4U 0114+65
during a \emph{Suzaku} observation covering the part of the orbit that included
the previously known low intensity emission of the source (dip) and the egress
from this state. This dip has been interpreted in previous works as an X-ray
eclipse. Notably, in this Suzaku observation, the count rate during and outside
the dip vary by a factor of only 2-4 at odds with the eclipses of other HMXBs,
where the intensity drops upto two orders of magnitude. The orbital intensity
profile of 4U 0114+65 is characterized by a narrow dip in the RXTE-ASM (2-12
\rm{keV}) light curve and a shallower one in the Swift-BAT (15-50 \rm{keV}),
which is different from eclipse ingress/egress behaviour of other HMXBs. The
time-resolved spectral analysis reveal moderate absorption column density
(N - 2-20 atoms ) and a relatively low
equivalent width ( 30 \rm{eV} \& 12 \rm{eV} of the iron K and
K lines respectively) as opposed to the typical X-ray spectra of HMXBs
during eclipse where the equivalent width is 1 \rm{keV}. Both XIS and
PIN data show clear pulsations during the dip, which we have further confirmed
using the entire archival data of the IBIS/ISGRI and JEM-X instruments onboard
\emph{INTEGRAL}. The results we presented question the previous interpretation
of the dip in the light curve of 4U 0114+65 as an X-ray eclipse. We thus
discuss alternative interpretations of the periodic dip in the light curve of
4U 0114+65.Comment: 16 pages, 7 figures, 1 table, Accepted in MNRA
- …