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21.
A GIS-based statistical methodology for landslide susceptibility zonation is described and its application to a study area
in the Western Ghats of Kerala (India) is presented. The study area was approximately 218.44 km2 and 129 landslides were identified in this area. The environmental attributes used for the landslide susceptibility analysis
include geomorphology, slope, aspect, slope length, plan curvature, profile curvature, elevation, drainage density, distance
from drainages, lineament density, distance from lineaments and land use. The quantitative relationship between landslides
and factors affecting landslides are established by the data driven-Information Value (InfoVal) — method. By applying and
integrating the InfoVal weights using ArcGIS software, a continuous scale of numerical indices (susceptibility index) is obtained
with which the study area is divided into five classes of landslide susceptibility. In order to validate the results of the
susceptibility analysis, a success rate curve was prepared. The map obtained shows that a great majority of the landslides
(74.42%) identified in the field were located in susceptible and highly susceptible zones (27.29%). The area ratio calculated
by the area under curve (AUC) method shows a prediction accuracy of 80.45%. The area having a high scale of susceptibility
lies on side slope plateaus and denudational hills with high slopes where drainage density is relatively low and terrain modification
is relatively intense. 相似文献
22.
We have measured the visible and infrared spectra and thermal behavior of the moleculebis-pyridal-magnesium-tetrabenz-porphyrin, the molecule proposed as the carrier of the diffuse interstellar bands. Of the six band coincidences reported by F. M. Johnson, only one, 4430 Å, occurs in our experiments. This coincidence requires a special environment, not likely in interstellar space. The infrared spectrum does not support Johnson's vibrational scheme. Our spectroscopic and thermal measurements contradict the hypothesis that this molecule causes the diffuse bands. 相似文献
23.
24.
Viral nervous necrosis(VNN)has emerged to become a major problem in the culture of larval and juvenile marine fish worldwide.Bioactive phytochemicals isolated from commonly available medicinal plants are often screened for their efficacy in controlling fish viral diseases.Occurrence of newer viral strains and resistance to existing antiviral drugs are problems currently as-sociated with treatment of VNN,which necessitates looking for alternate sources for effective antiviral drugs.The aim of the present study was to screen antiviral potential of gymnemagenol(C30H50O4)previously extracted from leaves of Gymnema sylvestre.The fish nodavirus,grouper nervous necrosis virus(GNNV)in infected Sahul Indian Grouper Eye(SIGE)cell lines were used to study the antiviral activity of gymnemagenol under in vitro conditions.The susceptibility of the virus to gymnemagenol was confirmed by measuring the viral titre(TCID50 mL?1)in virus-infected SIGE cells every 24 h.Gymnemagenol at 20 μg mL?1 inhibited the prolifera-tion of GNNV to 53% at the end of the 6th d by inhibiting the proliferation of GNNV-infected SIGE cells.The viable SIGE cells were reduced to 47% as determined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay.The viral titre(TCID50 mL?1)was also reduced to log 2.8 at the end of the 7th d in gymnemagenol-treated SIGE cells after inoculated with GNNV when compared to untreated control SIGE cell viral titre(log 4.1).Based on our results it can be concluded that gymnemagenol could be used as an antiviral agent against GNNV infection. 相似文献
25.
Early warning systems for slope instability are needed to alert users of accelerating slope deformation behaviour, enable evacuation of vulnerable people, and conduct timely repair and maintenance of critical infrastructure. Communities exposed to landslide risk in low- and middle-income countries seldom currently instrument and monitor slopes to provide a warning of instability because existing techniques are complex and prohibitively expensive. Research and field trials have demonstrated conclusively that acoustic emission (AE) monitoring can be an effective approach to detect accelerating slope movements and to subsequently communicate warnings to users. The objective of this study was to develop and assess a simple, robust, low-cost AE monitoring system to warn of incipient landslides, which can be widely deployed and operated by communities globally to help protect vulnerable people. This paper describes a novel AE measurement sensor that has been designed and developed with the cost constrained to a few hundred dollars (US). Results are presented from physical model experiments that demonstrate performance of the AE system in measuring accelerating deformation behaviour, with quantifiable relationships between AE and displacement rates. Exceedance of a pre-determined trigger level of AE can be used to communicate an alarm to users in order to alert them of a slope failure. Use of this EWS approach by communities worldwide would reduce the number of fatalities caused by landslides. 相似文献
26.
A three-dimensional model based on the Princeton Ocean Model (POM) has been implemented to study the circulation of the west coast of India. The model uses a curvilinear orthogonal horizontal grid with higher resolution near the coast (3–9 km) and a terrain following sigma coordinate in the vertical. The model is able to simulate Lakshadweep High and Lakshadweep Low (LL) during the winter and summer monsoons, respectively. During winter, the downwelling processes noticed along the coast help in the formation of temperature inversions. The inversions can be seen even up to the depths of ～50 m, which agrees with the available ARGO data in the region. Model simulations show that coastal upwelling off Kerala is at its peak in July. The intensity of upwelling reduces along the coast towards north. During the existence of LL, there is a cyclonic eddy in the sub-surface waters over the South-Eastern Arabian Sea, with vertical extent up to the depths of 100–150 m and it is strengthened due to the presence of northward counter current in the shelf region. The southerly coastal jet formed along the southern coast as a result of upwelling is noticed a westward shift along with LL. The location of the eddy off Kerala is tilted towards the open ocean with depth and our experiments suggest that this flow can be understood as a first baroclinic mode. 相似文献
27.
The tannery industry influences the gross domestic product/economic activity of any country, but the uncontrolled release of tannery effluents causes environmental degradation and increases health risks to human. The reason for the toxicity of tannery effluents is the presence of high concentrations of organic and inorganic chemicals used in the production of leather goods. Untreated or partially treated effluents discharged into surface water results in an increase in both chemical and biological oxygen demand as well as in an increase in the levels of total suspended solids, dissolved solids, and toxic metals in environmental bodies, especially in soil, water bodies, and water sediments. Various treatment techniques, such as physicochemical, biological, and advanced oxidation methods, which include chemical precipitation, electrocoagulation, aerobic or anaerobic treatment, wetland construction, and Fenton, electro-Fenton, and photo-Fenton processes are also described. This review also discusses the technical appropriateness and economic feasibility of reducing the effluent pollution load and solid waste emanating from the tannery industry. Considering the enhanced health risks in the tannery waste treatment and management regime, some green and advanced technologies should be explored. A sustainable green technology that avoids the use of toxic chemicals in the tanning process is seen well for ecological health. 相似文献
28.
Laboratory transmission IR spectra of relatively thick films (up to 500 m) of mixed H2O and SO2 ices were measured at several temperatures between 10 and 130 K in the range 5000-450 cm–1. In addition to the strong features due to crystalline SO2 the spectra reveal bands at 3668 cm–1, 3634 cm–1 (with some structure) and 3300 cm–1 which are identified with H2O in SO2 environment. Also, there is no overlap between any of the H2O bands with the 3584 cm–1 band of SO2 at any temperature in the above range. The implication of this result is that H2O, if present on Io, must be far less than 1 part in 105 SO2. 相似文献
29.
S. S. Aneesh Raj Madhu S. Nair G. R. K. S. Subrahmanyam 《Journal of the Indian Society of Remote Sensing》2017,45(6):979-991
In this paper two new schemes for resolution enhancement (RE) of satellite images are proposed based on Nonsubsampled Contourlet Transform (NSCT). First one is based on the interpolation on band pass images obtained by applying NSCT on the input low resolution image. Similar to Demirel and Anbarjafari (IEEE Trans Geosci Remote Sens 49(6):1997–2004, 2011), as an intermediate step, the difference between approximation band and the input low resolution image is added with all the band pass directional subbands, to obtain a sharper image. This method is simple and computationally efficient but lacks sharp recovery of the edges due to the interpolation of band pass images. To overcome this, another method is proposed to obtain the difference layer, where dictionary is built using patches which are extracted from high resolution training image subbands. Similar patches from the dictionary are then clustered together. This method gives a much sharper image than the first method. Subjective and objective analysis of proposed methods reveals the superiority of the methods over conventional and other state-of-the-art RE methods. 相似文献
30.
A three-dimensional numerical model is developed and used to study the coastal upwelling processes and corresponding seasonal changes in the sea level along the west coast of India. The upwelling and associated sea level variations are seen as a response of coastal ocean to pure wind stress forcing. The model is designed to represent coastal ocean physics by resolving surface and bottom Ekman layers as realistically as possible. The prognostic variables are the three components of the velocity field, temperature, salinity and turbulent energy. The governing equations together with their boundary conditions are solved by finite-difference techniques. Experiments are performed to investigate sea level fluctuations associated with the thermal response and alongshore currents of the coastal waters. The model is forced with mean monthly wind stress forcing of January, May, July and September representing northeast monsoon and different phases of the southwest monsoon. It is known from the observational study that the upwelling process reaches to the surface waters by May along the coastal waters of the extreme southwest peninsular region. The process is more intense in July compared to May and September and its strength decreases from south to north. However, during the northeast monsoon season, which is represented by January wind stress forcing in the model, downwelling is simulated along the coast. The model simulations of the coastal response are compared with the observations and are found to be in good agreement. The maximum computed vertical velocity of about 2.0 ×10 -3 cm s -1 is predicted in July in the southern region off the coast. 相似文献