827 research outputs found
Blending in Future Space-based Microlensing Surveys
We investigate the effect of blending in future gravitational microlensing
surveys by carrying out simulation of Galactic bulge microlensing events to be
detected from a proposed space-based lensing survey. From this simulation, we
find that the contribution of the flux from background stars to the total
blended flux will be equivalent to that from the lens itself despite the
greatly improved resolution from space observations, implying that
characterizing lenses from the analysis of the blended flux would not be easy.
As a method to isolate events for which most of the blended flux is
attributable to the lens, we propose to use astrometric information of source
star image centroid motion. For the sample of events obtained by imposing a
criterion that the centroid shift should be less than three times of the
astrometric uncertainty among the events for which blending is noticed with
blended light fractions , we estimate that the contamination of
the blended flux by background stars will be less than 20% for most () of the sample events. The expected rate of these events is
events/yr, which is large enough for the statistical analysis of the lens
populations.Comment: total 6 pages, including 5 figures, ApJ, in pres
Many Rivers to Cross: Evaluating the Benefits and Limitations of Strategic Environmental Assessment for the Koshi River Basin
This paper assesses the value of using Strategic Environmental Assessment (SEA) to account for the spatially and temporally diverse and diffuse impacts of hydropower development in South Asiaâs Koshi basin. A policy and practice review and key stakeholder interviews identified opportunities for SEA to improve existing planning procedures, but also barriers to effective adoption. Whilst stakeholders are interested in employing SEA to evaluate cumulative impacts, institutional blockages and an economic development imperative for power generation leave little space for consideration of alternative scenarios as part of SEA. The analysis is conducted through the formulation and application of a conceptual framework for SEA best practice which is then used to identify priority next-steps for SEA in the region
Relationship among seam strength, weft-way fabric strength and stitch density of B. Twill jute bag
The influence of weft-way fabric strength and stitch density on the seam strength of B. Twill jute bag has been studied. Study reveals that a correlation exists among seam strength, weft-way fabric strength and stitch density of B. Twill jute bags sewn with herakle stitches. A regression equation for seam strength as a function of two factors namely weft-way fabric strength and stitch density has been established
RGB vegetation indices applied to grass monitoring: a qualitative analysis
ArticleIn developing countries such as Brazil, research on low-cost remote sensing and
computational techniques become essential for the development of precision agriculture (PA),
and improving the quality of the agricultural products. Faced with the scenario of increasing
production of emerald grass (Zoysia JapĂŽnica) in Brazil, and the value added the quality of this
agricultural product. The objective of this work was to evaluate the performance of RGB (IV)
vegetation indices in the identification of exposed soil and vegetation. The study was developed
in an irrigated area of 58 ha cultivated with emerald grass at Bom Sucesso, Minas Gerais, Brazil.
The images were obtained by a RGB digital camera coupled to an remotely piloted aircraft. The
flight plan was setup to take overlapping images of 70% and the aircraft speed was 10 m s
-1
. Six
RGB Vegetation index (MGVRI, GLI, RGBVI, MPRI, VEG, ExG) were evaluated in a mosaic
resulting from the images of the study area. All of the VIs evaluated were affected by the
variability of lighting conditions in the area but MPRI and MGVRI were the ones that presented
the best results in a qualitative evaluation regarding the discrimination of vegetation and soil
Specially treated woven jute geotextiles for river bank protection
In this paper, studies on treatment of jute geotextile with isothiazolinone and fluorocarbon derivatives to impart antimicrobial and water repellent property have been reported for its improved end use specific performance. It is observed that the treated jute geotextile possesses higher durability in water as well as soil-water ambience
Density Perturbations in the Brans-Dicke Theory
We analyse the fate of density perturbation in the Brans-Dicke Theory, giving
a general classification of the solutions of the perturbed equations when the
scale factor of the background evolves as a power law. We study with details
the cases of vacuum, inflation, radiation and incoherent matter. We find, for
the a negative Brans-Dicke parameter, a significant amplification of
perturbations.Comment: 26 pages, latex fil
First Principles Study of Zn-Sb Thermoelectrics
We report first principles LDA calculations of the electronic structure and
thermoelectric properties of -ZnSb. The material is found
to be a low carrier density metal with a complex Fermi surface topology and
non-trivial dependence of Hall concentration on band filling. The band
structure is rather covalent, consistent with experimental observations of good
carrier mobility. Calculations of the variation with band filling are used to
extract the doping level (band filling) from the experimental Hall number. At
this band filling, which actually corresponds to 0.1 electrons per 22 atom unit
cell, the calculated thermopower and its temperature dependence are in good
agreement with experiment. The high Seebeck coefficient in a metallic material
is remarkable, and arises in part from the strong energy dependence of the
Fermiology near the experimental band filling. Improved thermoelectric
performance is predicted for lower doping levels which corresponds to higher Zn
concentrations.Comment: 5 pages, 6 figure
Formal Verification of Security Model Using SPR Tool
In this paper, formal verification methodologies and the SPR (Safety Problem Resolver) model checking tool are used for verifying a security model's safety. The SPR tool makes it possible to analyze security issues on security systems based on the access control model. To illustrate this approach, a case study of the Simple Access Control Model (SACM) is used and specific safety problems of the security model are analyzed using the SPR tool
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