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51.
The concept of the equivalent free surface has been extended to determine the seismic horizontal pullout capacity of shallow
vertical strip plate anchors buried in sand. The analysis has been done rigorously by using the method of stress characteristics.
The results have been expressed in the form of non-dimensional charts. The pullout resistance has been found to reduce quite
extensively with increase in the magnitude of horizontal earthquake acceleration. The results were compared with the previously
published data, and it was seen that the computed pullout resistance with the proposed method was found to be lowest.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
52.
Kusuma G. Rao V. N. Lykossov A. Prabhu S. Sridhar E. Tonkacheyev 《Journal of Earth System Science》1996,105(3):227-260
An attempt has been made here to study the sensitivity of the mean and the turbulence structure of the monsoon trough boundary
layer to the choice of the constants in the dissipation equation for two stations Delhi and Calcutta, using one-dimensional
atmospheric boundary layer model withe-ε turbulence closure. An analytical discussion of the problems associated with the constants of the dissipation equation is
presented. It is shown here that the choice of the constants in the dissipation equation is quite crucial and the turbulence
structure is very sensitive to these constants. The modification of the dissipation equation adopted by earlier studies, that
is, approximating the Tke generation (due to shear and buoyancy production) in theε-equation by max (shear production, shear + buoyancy production), can be avoided by a suitable choice of the constants suggested
here. The observed turbulence structure is better simulated with these constants. The turbulence structure simulation with
the constants recommended by Aupoixet al (1989) (which are interactive in time) for the monsoon region is shown to be qualitatively similar to the simulation obtained
with the constants suggested here, thus implying that no universal constants exist to regulate dissipation rate.
Simulations of the mean structure show little sensitivity to the type of the closure parameterization betweene-l ande-ε closures. However the turbulence structure simulation withe-ε. closure is far better compared to thee-l model simulations. The model simulations of temperature profiles compare quite well with the observations whenever the boundary
layer is well mixed (neutral) or unstable. However the models are not able to simulate the nocturnal boundary layer (stable)
temperature profiles. Moisture profiles are simulated reasonably better. With one-dimensional models, capturing observed wind
variations is not up to the mark. 相似文献
53.
To image the electrical conductivity distribution, fluxgate magnetometers are operated at five sites in Andaman and Nicobar region. Transfer functions are estimated for the period range 8–128 min, from nighttime transient geomagnetic variations, using robust regression analysis. The observed induction arrows in Andaman Islands are found to point towards east despite deep sea located towards its west. This indicates that fore-arc basin (Andaman–Nicobar deep) is more conducting than the region of outer non-volcanic Island arc.Thin sheet model requires the conductance of 10,000–35,000 S (with increase conductivity towards the south) for explaining the observed induction pattern. The observed induction pattern at Andaman–Nicobar stations can be explained in terms of high conducting Cretaceous–Tertiary sediments filling the Andaman–Nicobar deep. High conductivity over Invisible bank has been attributed to the partial melts/volatile fluids derived from the subducting Indian plate that are intruding into the eastern margin of fore-arc basin through the West Andaman Fault (WAF).The induction pattern at Great Nicobar station (Campbell Bay) may be related to the highly conducting sediments filling the Mergui basin along with mafic intrusions. Also crustal transition occurs below the Mergui Terrace at the Malayan coast contributing to the enhanced conductivity anomaly. 相似文献
54.
P. Lakshmi Srinivasa Rao D. Srinu M. A. Rasheedd M. S. Kalpana D. J. Patil A. M. Dayal 《Journal of the Geological Society of India》2013,82(6):666-674
Direct correlation have been observed between certain trace element and hydrocarbon anomalies in the near subsurface soils of Vindhyan basin, India. This relationship with hydrocarbon is very useful in hydrocarbon exploration. 52 soil samples from Vindhyan basin were collected from a depth of 2.5m. All the soil samples were analyzed for light hydrocarbon, isotope and trace element concentrations. The adsorbed light gaseous hydrocarbon analyses show the presence of methane (8–328 ppb), ethane (0–27 ppb) and propane (0–11 ppb) respectively and these values indicate the presence of hydrocarbon micro-seepage in the study area. The carbon isotopic values determined for methane and ethane for these soil samples are (?26.41 to ?47.70 ‰ PDB) and (?20.07 to ?35.30 ‰ PDB) respectively and they are thermogenic in nature. The trace element concentrations of nickel (33–220 ppm), vanadium (72–226 ppm), copper (20–131 ppm), chromium (94–205 ppm), zinc (66–561 ppm) and cobalt (9–39 ppm) have higher than the normal concentrations in soils. Trace element concentrations are used to plot with the data obtained from light gaseous hydrocarbon concentrations and carbon isotopic values of soil samples of the Vindhyan basin. Trace element anomalies have been observed around the hydrocarbon anomalies in the study area. 相似文献
55.
F. Ghasemi F. Tabandeh Ph.D. B. Bambai Ph.D. K. R. S. Sambasiva Rao Ph.D. 《International Journal of Environmental Science and Technology》2010,7(3):457-464
Detoxification of synthetic dyes is one of the main challenges in clearing textile industry wastes. Biodegradation of azo-dyes using Phanerochaete chrysosporium is one the most environmentally friendly methods available. The main enzymes responsible for mycodecolorization process are lignin and manganese peroxidases. Here, optimization of expression conditions has been carried out with manipulating culture condition and nutrient sources. Therefore, the effects of buffer and temperature as well as nitrogen source on lignin peroxidase and manganese peroxidase production were investigated at two levels and four levels, respectively. For this purpose, P. chrysosporium RP78 based on Taguchi design of experiment has been applied. Maximum lignin and manganese peroxidase activities of 182 ± 2.5 U/L and 850 ± 41 U/L were obtained under predicted optimum conditions, respectively. Thereby, about 100 % decolorization was achieved after 24 h for two most widely used groups of azo dyes in textile industry consisting reactive and acidic. The physical adsorption of the azo dyes by mycelia was not significant which indicated that the enzymatic degradation of the dyes was occurred. Time profile of these enzymes showed that manganese peroxidase was peaked on 9th day while lignin peroxidase peaked on 13th day and remained stable in the culture. The extracellular expression profiles of both were studied by 2 dimensional gel electrophoresis to partially characterize the enzymes. 相似文献
56.
The Nature and Distribution of Particulate Matter in the Mandovi Estuary,Central West Coast of India
Pratima Mohan Kessarkar Venigalla Purnachandra Rao Ranjan Shynu Prakash Mehra Blossom E. Viegas 《Estuaries and Coasts》2010,33(1):30-44
Systematic seasonal variations of suspended particulate matter (SPM) along a 44-km transect of the Mandovi estuary reveal
that the concentrations of SPM are low at river-end stations, increase generally seaward, and are highest at sea-end stations
of the estuary. An estuarine turbidity maximum (ETM) occurs at sea-end stations during June–September when river discharge
is high and also in February–May when river discharge is low. These are the two windiest times of year, the former associated
with the southwest monsoon and the latter characterized by a persistent sea breeze. The salinity vs. SPM plot shows that high
SPM is a seaward deposit and skewed landward. Suspended matter comprised of floccules, fecal pellets, and aggregates that
consist of clay and biogenic particles occur everywhere in the estuary. Diatoms are the most common and are of marine type
at the sea-end and freshwater-dominated at river-end stations of the estuary. SPM is characterized by kaolinite- and smectite-rich
clay mineral suites at the river- and sea-end stations, respectively. Smectite concentrations increase seawards with the increase
in SPM content and are not influenced by salinity. Wind-driven waves and currents and biogeochemical processes at the mouth
of estuary likely play an important role in the formation of ETM in resuspension and transformation of SPM into floccules
and aggregates and in their upkeep or removal. 相似文献
57.
58.
Summary An entirely new procedure is proposed in this paper for interpreting anomalies of dykes. This reduces the ambiguity in magnetic interpretation. Measurements of the first vertical derivative simplifies the problem of interpretation and also supplies additional information concerning the parameters of a dyke. The first vertical derivative profile cuts the distance axis at two points whose separation is related to the depth and direction of magnetisation of a dyke. 相似文献
59.
R. Krishna Rao Vupputuri 《Pure and Applied Geophysics》1978,117(3):448-485
two-dimensional time dependent model of the stratosphere incorporating the major interactions between radiative-photochemical and dynamical processes is described. The main prognostic equations considered are the thermodynamic equation and the general conservation equation for the minor chemical constituents representing the odd oxygen (O
x
=O+('D)+O3), odd hydrogen (HO
x
=HO+HO2), N2O, odd nitrogen (NO
x
=NO+NO2+HNO3), CF2Cl2, CFCl3 and odd chlorine (Cl
x
=Cl+ClO+HCl). The zonal wind and mean meridional circulations are determined diagnostically by the integration of the thermal wind equation and the stream function equation in the meridional plane espectively. The large scale eddy processes are parameterized in terms of zonal mean quantities using the generalized diffusion formulation on a sloping surface. The radiative heating and cooling and the hotochemical sources and sinks are incorporated in a form which allows for the major interactions among the minor trace constituents, temperature and mean circulation.Two integrations consisting of natural stratosphere and a stratosphere contaminated by the chlorofluoromethanes through lower boundary fluxes are carried out for 23 model years by changing the declination of the sun every day and using 6-hour time step. The model simulations of temperature, mean circulation, ozone, HO
x
, N2O and NO
x
in the meridional plane for the normal stratosphere, show satisfactory agreement with the available observations. Based on the results of second integration it is found that the injection of chlorofluoromethanes in the atmosphere at the estimated current production rates can lead to significant changes in the meridional distribution of ozone, temperature and NO
x
in the middle and upper stratosphere. The results also indicate that the percentage total ozone depletion increases from tropics to high latitudes and from summer to winter high latitudes. Also discussed are the results of additional experiments incorporating the reaction of HO2 with NO and the reactions involving ClNO3. 相似文献
60.