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1.
The true potential energy curves for the electronic ground states of astrophysically important AlH and CaH molecules are constructed by the Rydberg-Klein-Rees method. Empirical potential functions, of three-parameters by Lippincott, of five-parameters by Hulburt and Hirsch-felder and, of electronegativity by Szöke and Baitz, are examined for the adequacy to represent the true curve. From the best-fitting function, the dissociation energiesD 0 0 of AlH and CaH molecules are estimated to be 2.99 ± 0.08 and 2.72 ± 0.06 eV respectively. The force constants indicate that these values are of correct magnitude. 相似文献
2.
A. Boominathan G. R. Dodagoudar A. Suganthi R. Uma Maheswari 《Journal of Earth System Science》2008,117(2):853-863
Chennai city suffered moderate tremors during the 2001 Bhuj and Pondicherry earthquakes and the 2004 Sumatra earthquake. After the Bhuj earthquake, Indian Standard IS: 1893 was revised and Chennai city was upgraded from zone II to zone III which leads to a substantial increase of the design ground motion parameters. Therefore, a comprehensive study is carried out to assess the seismic hazard of Chennai city based on a deterministic approach. The seismicity and seismotectonic details within a 100 km radius of the study area have been considered. The one-dimensional ground response analysis was carried out for 38 representative sites by the equivalent linear method using the SHAKE91 program to estimate the ground motion parameters considering the local site effects. The shear wave velocity profile was inferred from the corrected blow counts and it was verified with the Multichannel Analysis of Surface Wave (MASW) test performed for a representative site. The seismic hazard is represented in terms of characteristic site period and Spectral Acceleration Ratio (SAR) contours for the entire city. It is found that structures with low natural period undergo significant amplification mostly in the central and southern parts of Chennai city due to the presence of deep soil sites with clayey or sandy deposits and the remaining parts undergo marginal amplification. 相似文献
3.
V. C. Padmanaban M. S. Giri Nandagopal G. Madhangi Priyadharshini N. Maheswari G. Janani Sree N. Selvaraju 《International Journal of Environmental Science and Technology》2016,13(6):1591-1606
Industrial effluents containing persistent pollutants play a significant role in environmental pollution. Classical techniques such as chlorination, coagulation, ion flotation, membrane process and sedimentation that have been used to decontaminate polluted water are incapable of efficient degradation due to the generation of secondary pollutants. Photocatalysis, an advanced oxidation process in which the photoreaction is accelerated by the irradiation of catalyst, has shown efficient degradation of recalcitrant in water system. Usage of nanoparticles as homogenous photocatalyst has become prevalent due to their improved properties such as large surface-to-volume ratio, controlled uniform particle size and its composition which enhances the degradation rate. The recombination of holes and electron pair which is considered to be the limitation in homogenous system can be overcome by nanocomposites or heterogeneous photocatalysts. This system decreases the rate of recombination, leading to effective degradation of individual pollutants because of their enhanced physicochemical and structural properties. In recent years, heterogeneous nanophotocatalytic processes employing titanium dioxide (TiO2) and zinc oxide (ZnO) composites have gained immense research interest as an effective wastewater treatment method because of its efficacy in decomposing and mineralizing the hazardous organic and inorganic pollutants utilizing the UV and visible photons. This paper reviews about the process, synthesis and parameters influencing photocatalytic reaction and their kinetics with much emphasize on types of nanoparticles and nanocomposites and its application in wastewater treatment. 相似文献
4.
From the wave refraction diagrams it is delineated that the Jaigad Head and Warori Bluff are the zones of wave energy convergence and the Narvan and Ambwah bays the areas of wave energy divergence. The presence of two distinct mineral phases noticed at the Jaigad, Ambwah and Varvade bays shows that there are two different circulations of sediment movements. The presence of natural barriers restricts the movement of sediment along the coast. The sand bar at the mouth of the Jaigad Bay has different orientations during the monsoon and non-monsoon periods causing obstruction to navigation during the former period. 相似文献
5.
The Franck-Condon factors and r-centroids, which are very closelyrelated to relative vibrational transition probabilities, have beenevaluated by the more reliable numerical integration procedure forthe bands of c
1 - a
1 and f
1 - a
1 systems of CN
+ and C
2 +
u- X
2 +
g and D
2 g- A
2 u systems of N
+
2 molecular ions of astrophysical interest,using a suitable potential. 相似文献
6.
Distribution of arsenic and mercury in subtropical coastal beachrock,Gulf of Mannar,India 总被引：1，自引：0，他引：1
J Dajkumar Sahayam N Chandrasekar S Krishna Kumar G Victor Rajamanickam 《Journal of Earth System Science》2010,119(1):129-135
An assessment of coastal pollution was made on the basis of trace element concentrations (arsenic — As, mercury — Hg) in the
Gulf of Mannar. The beachrock samples were collected along the coastal tracts between Rameswaram and Kanyakumari. The samples
were dried and digested to determine the As and Hg using atomic absorption spectrophotometer (AAS-air-acetylene and nitrous
oxide method). The As and Hg accumulation status of the beachrock was assessed using geo-accumulation index values (I
geo). The accumulation of As and Hg in the beachrock ranges from 2.75 to 20.72 μg g−1 and from 0.06 to 0.31 μg g−1, respectively. The As and Hg concentrations in the beachrocks are compared with crustal average values and average of other
region sediments. The possible source of the contamination is from atmospheric deposition and anthropogenic activities. 相似文献
7.
Use of Surface Waves in Statistical Correlations of Shear Wave Velocity and Penetration Resistance of Chennai Soils 总被引：1，自引：0，他引：1
R. Uma Maheswari A. Boominathan G. R. Dodagoudar 《Geotechnical and Geological Engineering》2010,28(2):119-137
Shear wave velocity (V
s) is one of the most important input parameter to represent the stiffness of the soil layers. It is preferable to measure
V
s by in situ wave propagation tests, however it is often not economically feasible to perform the tests at all locations. Hence,
a reliable correlation between V
s and standard penetration test blow counts (SPT-N) would be a considerable advantage. This paper presents the development
of empirical correlations between V
s and SPT-N value for different categories of soil in Chennai city characterized by complex variation of soil conditions. The
extensive shear wave velocity measurement was carried out using Multichannel Analysis of Surface Waves (MASW) technique at
the sites where the SPT-N values are available. The bender element test is performed to compare the field MASW test results
for clayey soils. The correlations between shear wave velocity and SPT-N with and without energy corrections were developed
for three categories of soil: all soils, sand and clay. The proposed correlations between uncorrected and energy corrected
SPT-N were compared with regression equations proposed by various other investigators and found that the developed correlations
exhibit good prediction performance. The proposed uncorrected and energy corrected SPT-N relationships show a slight variation
in the statistical analysis indicating that both the uncorrected and energy corrected correlations can predict shear wave
velocity with equal accuracy. It is also found that the soil type has a little effect on these correlations below SPT-N value
of about 10. 相似文献
8.
V J Loveson A R Gujar R Barnwal Richa Khare G V Rajamanickam 《Journal of Earth System Science》2014,123(6):1375-1385
In this study, results of GPR profiling related to mapping of subsurface sedimentary layers at tsunami affected Karaikal beach are presented . A 400 MHz antenna was used for profiling along 262 m stretch of transect from beach to backshore areas with penetration of about 2.0 m depth (50 ns two-way travel time). The velocity analysis was carried out to estimate the depth information along the GPR profile. Based on the significant changes in the reflection amplitude, three different zones are marked and the upper zone is noticed with less moisture compared to other two (saturated) zones. The water table is noticed to vary from 0.5 to 0.75 m depth (12–15 ns) as moving away from the coastline. Buried erosional surface is observed at 1.5 m depth (40–42 ns), which represents the limit up to which the extreme event acted upon. In other words, it is the depth to which the tsunami sediments have been piled up to about 1.5 m thickness. Three field test pits were made along the transect and sedimentary sequences were recorded. The sand layers, especially, heavy mineral layers, recorded in the test pits indicate a positive correlation with the amplitude and velocity changes in the GPR profile. Such interpretation seems to be difficult in the middle zone due to its water saturation condition. But it is fairly clear in the lower zone located just below the erosional surface where the strata is comparatively more compact. The inferences from the GPR profile thus provide a lucid insight to the subsurface sediment sequences of the tsunami sediments in the Karaikal beach. 相似文献
9.
P. Sriramachandran S. P. Bagare N. Rajamanickam K. Balachandrakumar 《Solar physics》2008,252(2):267-281
High-resolution Fourier Transform Spectrometer sunspot umbral spectra of the National Solar Observatory/National Optical Astronomy
Observatory at Kitt Peak were used to detect rotational lines from 19 electronic transition bands of the molecules LaO, ScO
and VO, in the wavenumber range of 11 775 to 20 600 cm−1. The presence of lines from the following transitions is confirmed: A
2
Π
r1/2 – X
2
Σ
+(0, 0; 0, 1), A
2
Π
r3/2 – X
2
Σ
+(1, 0), B
2
Σ
+ – X
2
Σ
+(0, 0; 0, 1; 1, 0) and C
2
Π
r1/2 – A′2Δ
r3/2(0, 0; 1, 1) of LaO; A
2
Π
r3/2 – X
2
Σ
+(0, 0), A
2
Π
r1/2 – X
2
Σ
+(0, 0) and B
2
Σ
+ – X
2
Σ
+(0, 0) of ScO; and C
4
Σ
− – X
4
Σ
−(0, 1; 1, 0; 0, 2) and (2, 0) of VO. However, the presence of A
2
Π
r3/2 – X
2
Σ
+(0, 0) and C
2
Π
r3/2 – A′2Δ
r5/2(0, 0; 1, 1) of LaO and C
4
Σ
− – X
4
Σ
−(0, 0) of VO are found to be doubtful because the lines are very weak, and detections are difficult owing to heavy blending
by strong rotational lines of other molecules. Equivalent widths are measured for well-resolved lines and, thereby, the effective
rotational temperatures are estimated for the systems for which the presence is confirmed. 相似文献
10.
The cross-shore profile and the textural distribution of foreshore sediments of Ganpatipule beach along Maharashtra coast covering two annual cycles are examined. Ganpatipule beach depicts erosion and accretion of the berm, reduction and widening of foreshore widths during the monsoon (June–September) and post-monsoon (October–May), respectively with net sediment accretion during the study period due to the changes in the wave characteristics. A direct correlation is observed between the median sediment grain size and beach-face slopes signifying high wave energy ensuing to a gentle to very gentle slope. The sediments are mainly medium grain size, moderately well sorted, bimodal, very fine skewed to very coarse skewed and very platykurtic to very leptokurtic in nature. The binary plots of the textural parameters (mean, skewness, kurtosis, and standard deviation) depicted a characteristic beach environment of deposition. The study shows that the sediment is concentrated in the environment of rolling and bottom suspension. The study on grain size distribution of sediments could be used to assess the wave energy condition prevailing along the coastal area. 相似文献