8,039 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
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
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
On conventional and harmonic load flow analysis
In conventional power flow analysis, simultaneous linear equations numbering in thousands must be solved repeatedly and in many instances on-line. Luckily the matrix of coefficients of these equations is sparse with a few elements in each row. Therefore for a faster solution and to save computer memory, sparsity must be exploited and an optimal ordering of the equations must be sought. When considering harmonics, the number of the simultaneous equations to be solved is multiplied and therefore, considering sparsity and optimal ordering is doubly important.
In this thesis a software package for optimizing computation time and memory requirements through exploitation of sparse matrices for Power System Bus Equations was developed. Exploitation of sparsity was accomplished by utilizing a packed storage scheme and special programming.
HARMFLO package was obtained from E.P.R.I. and was used to compare the results obtained using the developed package with those obtained from HARMFLO. The equations that must be solved for a harmonic load flow analysis are detailed and an example is given. A subroutine to modify the admittance matrix in accordance with the order of harmonics was developed
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