We employ an Artificial Neural Network (ANN) based technique to develop a pipeline for automated segregation of stars from the galaxies to be observed by Tel-Aviv University Ultra-Violet Experiment (TAUVEX). We use synthetic spectra of stars from UVBLUE library and selected International Ultraviolet Explorer (IUE) low-resolution spectra for galaxies in the ultraviolet (UV) region from 1250 to 3220 Å as the training set and IUE low-resolution spectra for both the stars and the galaxies as the test set. All the data sets have been pre-processed to get band integrated fluxes so as to mimic the observations of the TAUVEX UV imager. We also perform the ANN based segregation scheme using the full length spectral features (which will also be useful for the ASTROSAT mission). Our results suggest that, in the case of the non-availability of full spectral features, the limited band integrated features can be used to segregate the two classes of objects; although the band data classification is less accurate than the full spectral data classification. 相似文献
The deposition of ochreous is common by a consequence of acid mine drainage (AMD). The ochreous precipitated from the AMD
sites around Tertiary coalfield of Assam, India were collected and characterized by X-ray diffractometry (XRD), Fe to S molar
ratio, ammonium oxalate acid (pH 3.0) extraction, fourier-transform infrared spectroscopy (FTIR), field emission scanning
electron microscopy (FESEM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The ochreous mainly
consists of goethite, schwertmannite, ferrihydrite and jarosite. Mineralogy of ochreous was controlled by the pH whereas formation
of ferrihydrite was favored at high organic carbon content. Role of bacteria for the formation of secondary minerals was observed.
Mobility of metals was controlled by the ochreous, and they were also retained during the process of phase transformation
of poorly ordered iron-oxyhydroxysulfates into the stable forms. 相似文献
Accurate estimation of soil moisture through remote sensing technique has been a challenge till date. In optical and thermal
remote sensing, there is no index developed to detect the changes in soil moisture levels. In microwave region, soil roughness
and other target parameters equally affect the technique for soil moisture estimation. Therefore, a computational technique
in C language based on Shannon’s Information Theory (Shannon, 1948) has been developed to calculate total information content
from multispectral radiometer data. The total information content is a compressed single value, which quantifies the information
content of soil spectral reflectance in the electromagnetic spectrum range (400–1100 nm) under study. This technique was tested
over a wide range of soil moisture levels. The study revealed that as compared to other techniques total information content
index is very sensitive to change in moisture content of soil. This technique could not only quantify the soil moisture content
in optical and near infra red region, but also led to a simplified one dimensional separability and clustering analysis. 相似文献
Contamination of groundwater by nitrates leaching from intensive agricultural and livestock operations have become a major concern for surrounding communities that use groundwater as their water supply. High levels of nitrate in drinking water poses a significant risk to human health, i.e., methaemoglobinaemia (“blue baby” syndrome).
The traditional pump-and-treat method is ineffective in medium to fine-textured agricultural soils due to the low hydraulic conductivity. This paper presents the results of a laboratory experiment investigating the feasibility of using electrokinetic treatment in retaining, accumulating, moving and remediating nitrates in a silty loam soil under hydraulic gradients.
A hydraulic gradient of 1.25 was applied to the horizontal soil columns to simulate a groundwater movement system. The study was performed in two stages. During the first stage of the experiment, the anode located at the inflow end of the columns was able to retard the movement of nitrates even under a hydraulic gradient of 1.25. After 15 days of flow, the effluent nitrate concentration in the control column rose to 90 mg l−1 while no nitrates were detected in the effluent from columns subjected to the electrokinetic treatment.
After 15 days, the polarity of the electrodes was switched and this second stage lasted another 20 days. The cathode near the inflow end promoted the conversion of nitrates entering the column to other forms. The anode near the outflow end promoted the migration and accumulation of negatively charged nitrate ions towards the outflow end. By the 12th day, the nitrate concentrations in the electrokinetically treated columns were brought down to <5 mg NO3-N l−1. Electrokinetic treatment retarded nitrate movement against a hydraulic gradient of 1.25 and effectively restored a medium-textured soil contaminated with NO3-N.
The NO2-N level remained below 1 mg l−1 throughout the experiment. The hydraulic conductivity varied between 1.0E–7 and 3.6E–7 m s−1. The current requirement varied between 3 and 6 mA. 相似文献
Visual interpretation of IRS ID LISS-III fused with PAN data (1:12,500 scale) ofPatloinala micro-watershed of Puruliya district, West Bengal was carried out for delineating the physiographic units based on the variations
in image characteristics. The major physiographic units identified were upland(Tanr), medium land(Baid), and low land(Bahal andKanali). The satellite remote sensing data coupled with ground truth were translated in terms of soils using composite interpretation
map as base. The abstraction level attained was phases of soil series based on Soil Taxonomy. On the basis of physiographic
variation and soil or soil site characteristics such as texture, depth, slope, erosion etc. the problem areas were identified
and land use plan has been suggested for the overall development of the micro-watershed. 相似文献
The increasing demand for water in developing countries, like India, requires efficient water management and resource allocation. This is crucial to accurately assess and predict hydrological processes such as streamflow, drought, and flood. However, simulations of these hydrologic processes from various hydrological models differ in their accuracy. By analyzing different characteristics of hydrological models, selection scores can be used to select the best model for the intended purpose based on their inherit strengths (i.e., some models are better for streamflow prediction). In this study, 13 different criteria were used for the model selection scores including temporal and spatial resolutions, and processes involved. Thereafter, based on different scores, we selected two different hydrological models for streamflow prediction in the Kangsabati River Basin (KRB) in eastern India, namely (1) Génie Rural à 4 paramètres Journalier (GR4J), a conceptual model, and (2) Variable Infiltration Capacity (VIC), a semi-distributed model. The models were calibrated against the daily observed streamflow at upper KRB (Reservoir) and lower KRB (Mohanpur) from 2000 to 2006 and validated during the period from 2008 to 2010. Despite the differences in model structure and data used, both models simulated streamflow at a daily time scale with Nash–Sutcliffe coefficient of 0.71–0.82 for the VIC model and 0.63–0.71 for the GR4J. Due to the simpler structure, parsimonious nature, fewer parameters, and reasonable accuracy, the results suggest that a conceptual rainfall—runoff model like GR4J can be used in data-deficient conditions.
The lowest unit of the Talchir Formation of Talchir Basin, Orissa, was described by pioneer workers as the ‘basal boulder
bed’. In an attempt to explain the co-existence of gravel and clay, materials of contrasting hydraulic properties, a probable
situation resembling the effects of the action of ground-ice enabled boulders to be carried down by sluggish currents resulting
in an intermixture of large boulders and fine mud was conceived. Misinterpretation of this conclusion led to a general tendency
to describe the ‘basal boulder bed’ as ‘glacial tillite’. However, the unit described as ‘basal boulder bed’ is actually represented
by a matrix rich conglomerate with pockets of normally graded silty clay. The present study reveals that the depositional
imprints preserved in this part of the sedimentary succession indicate emplacement of successive debris flows generated through
remobilization of pre-existing unconsolidated sediments. Small pockets of fine-grained turbidites presumably deposited from
the entrained turbidity currents associated with the debris flows suggest the composite character of the debris flow deposit. 相似文献
The Advanced WiFS sensor of RESOURCESAT- 1 satellite offers significantly improved specifications compared to the WiFS sensor
onboard IRS IC, P3 and ID satellites. The improvements are in terms of spatial resolution, radiometry (quantisation levels)
and number of spectral bands. In the present study, an attempt has been made to quantify the gains due to these enhanced specifications.
The study has been carried out in a predominantly agricultural area. For the study reported here, one set of overlapping data
acquired on the same day by WiFS and AWiFS sensors has been selected. This eliminates the need of atmospheric correction/
normalization for comparison. The effect of spatial resolution has been studied by applying ISODATA spectral clustering algorithm
with number of clusters set at three different levels, viz., 10, 20 and 30. They are assumed to mimic first, second and third
level classification, respectively. Output images were filtered using 3 × 3 majority filter. Homogeneous polygons having area
less than 1/2 and 1 pixel of WiFS were recorded. This indicates the minimum loss by using WiFS data. A relative gain of 10
– 15 % is observed due to improvement in spatial resolution. For comparison of radiometry, local variance measure was used.
It was observed that local variance is much larger for AWiFS data in comparison with WiFS data. This indicates presence of
enhanced local contrast, hence heterogeneity, in AWiFS data over WiFS data. Separability analysis has been carried out to
demonstrate improvements due to two additional spectral bands (Green and SWIR). 相似文献
