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841.
Many environmental pollution issues from highway runoff increasingly become a serious concern, which has been revealed by many previous studies. However, very less information is available on the distribution characteristics of pollutants and their mutual influence in highway runoff. In this paper, the partitioning of pollutant and particle size distribution were investigated based on the initial road runoff of 47 rainfall events from July 2007 to May 2009 on the Lukou section of the Nanjing Airport Expressway, China. This study is emphasizing on the analysis of the mutual impact of pollutant distribution and the relationship between particle size and pollutant distribution. The impact of rainfall characteristics, water temperature, and pH values in runoff samples on the pollutant distribution was also studied. Result shows that partitioning of different pollutants was varying significantly. Volume of particles in different sizes was different, with the highest volume of particles of 21–75 µm size. The distribution of COD highly affected the distribution of TN, and somewhat promoted the distribution of Pb in particles. TP, Pb, and Cd promoted distribution of each other's in particles. There was better competition among Zn, Cu, and Cd, when heavy metals combined with particles. The particles ranged between 21 and 75 µm size had an obvious impact on the distribution of COD, Pb, and TN in the particulate matter. TP in the particulate matter mainly distributed in particles ranged in 151–300 µm size. Rainfall duration significantly affected the Pb in particulate matter. The distribution of Zn in the particulate matter mostly was affected by pH values. 相似文献
842.
Nand Lal Sharma Jagdish Chand Kuniyal Mahavir Singh Manum Sharma Raj Pal Guleria 《Acta Geophysica》2011,59(2):334-360
The measurements using a ground based multi wavelength radiometer (MWR) at Mohal (31°54′N, 77°07′E, 1154 m AMSL) in the Kullu
valley of Northwestern Himalayan region show that the spectral aerosol optical depth (AOD) and turbidity coefficient, β, are high in summer, moderate in monsoon season, low in winter and lowest in autumn, while wavelength exponent, α, has an opposite trend. Average annual value of AOD at 500 nm is 0.24±0.01, 0.43±0.02, and 0.28±0.02; that of β is 0.14±0.01, 0.22±0.02, and 0.17±0.03; and that of α is 1.06±0.09, 1.16±0.10, and 0.86±0.13, respectively, for clear, hazy and partially clear sky days. The considerably greater
value of β on hazy days indicates more coarse particles in mountain haze. The fractional asymmetry factor (AF) is more negative in summer
and autumn months. The AOD and β have significantly positive correlation with temperature and wind speed, suggesting high AODs and turbidity on hot and windy
days. 相似文献
843.
Gravity and magnetic studies have been carried out to map the different depth formations of alluvium, Gondwana, Vindhyan, Mahakoshal, and the crystalline basement in the Narmada–Son lineament (NSL) near the Sahdol–Katni area, India. Higher elevations in the northern part of the study area have lower gravity; the southern part of the study area, however, is moderately elevated and also has a higher gravity anomaly, which justifies the isostatic adjustment. This indicates the presence of high-density material, for example Mahakoshal rocks, in the upper crust which causes the higher anomaly value. The Mahakoshal rocks are widely exposed at Mau, Chanaura, Nadawar, Khamaria, Umria, and near the Tala–Barhi area and also extend from Sidhi to Agoni village further east of the area. The Mahakoshal rocks are thinner between the river Son and Tikwa village which causes a different gravity anomaly pattern changing from the NNE–SSW direction to the N–S direction. However, the trend of magnetic anomaly follows the same pattern toward the NNE–SSW direction, mainly because of the effect of the crystalline basement. Two magnetic highs are prominent in the Tikwa and Amarpur regions, 800 and 400 nTesla, respectively, because of the presence of the crystalline basement. The depth of the crystalline basement obtained by 2½ D gravity–magnetic modelling varies from 2.7 to 2.9 km. From spectral analysis the average depth of the crystalline basement varies from 2.83 to 3.05 km. The different crustal depth sections obtained by 2½ D simultaneous gravity–magnetic modelling correlate well with other constrained data. 相似文献
844.
This study examines the short-range forecast accuracy of the Pennsylvania State University-National Center for Atmospheric
Research Mesoscale Model (MM5) as applied to the July 2006 episode of the Indian summer monsoon (ISM) and the model's sensitivity
to the choice of different cumulus parameterization schemes (CPSs), namely Betts-Miller, Grell (GR) and Kain-Fritsch (KF).
The results showed that MM5 day 1 (0–24 h prediction) and day 2 (24–48 h prediction) forecasts using all three CPSs overpredicted
monsoon rainfall over the Indian landmass, with the larger overprediction seen in the day 2 forecasts. Among the CPSs, the
rainfall distribution over the Indian landmass was better simulated in forecasts using the KF scheme. The KF scheme showed
better skill in predicting the area of rainfall for most of the rainfall thresholds. The root mean square error (RMSE) in
day 1 and day 2 rainfall forecasts using different CPSs showed that rainfall simulated using the KF scheme agreed better with
the observed rainfall. As compared to other CPSs, simulation using the GR scheme showed larger RMSE in wind speed prediction
at 850 and 200 hPa over the Indian landmass. MM5 24-h temperature forecasts at 850 hPa with all the CPSs showed a warm bias
of the order of 1 K over the Indian landmass and the bias doubled in 48-h model forecasts. The mean error in temperature prediction
at 850 hPa over the Indian region using the KF scheme was comparatively smaller for all the forecast intervals. The model
with all the CPSs overpredicted humidity at 850 hPa. The improved prediction by MM5 with the KF scheme is well complemented
by the smaller error shown by the KF scheme in vertical distribution of heat and mean moist static energy in the lower troposphere.
In this study, the KF scheme which explicitly resolve the downdrafts in the cloud column tended to produce more realistic
precipitation forecasts as compared to other schemes which did not explicitly incorporate downdraft effects. This is an important
result especially given that the area covered by monsoon-precipitating systems is largely from stratiform-type clouds which
are associated with strong downdrafts in the lower levels. This result is useful for improving the treatment of cumulus convection
in numerical models over the ISM region. 相似文献
845.
Systematic rock mass characterization is an integral part of rock engineering practices. In the present scenario several classifications
are in used for rock mass characterization for tunnelling. The present paper discusses engineering geological investigations
carried out for Punasa tunnel, a part of Narmada Sagar project. The horse shoe shaped tunnel is 3675.25 m long and 9 m in
diameter. This straight and free flow tunnel has been constructed in basaltic lava flows erupted during Cretaceous to Eocene
age, belonging to poor to fair rock mass rating (RMR) and extremely poor to good in tunnel quality (Q-system). The values
of RMR and Q-system ranges from 29 to 74 and 0.0825 to 13.33 respectively. 相似文献
846.
The drainage basin parameters of the groundwater-fed Chhoti Gandak River originating in the terai area of the Ganga Plain
were analyzed using topographical sheets, satellite data, and field documentation with emphasis to its implication for flood
mitigation and recharging of groundwater. The analyses indicate dominance of first order streams, gentle slope gradient, low
surface run-off, low sediment production, high infiltration rate, and low value of basin relief. The low water storage capacity,
spreading of water and concentration of peak discharge in the distal part of the river basin explain that whenever precipitation
is high in the catchment area there is flood in the distal part of the basin. The bifurcation ratio value (4.34) of this basin
describes that the drainage is carved naturally by slope and local relief and not influenced by geological structures like
lineaments and faults. 相似文献
847.
National Highway-39 is the only lifeline of the state of Manipur. The sector between Karong and Mao is highly landslide prone
and frequently blocked the NH-39. The area is represented by Disang and Barail Groups of rock. Considering the importance
of NH-39, landslide susceptibility zonation studies along NH-39 between Karong and Mao were carried out following GSI guideline,
a modified form of BIS (1998). 相似文献
848.
Hari B. Srivastava Vaibhava Srivastava Rajesh K. Srivastava Chandra Kant Singh 《Journal of the Geological Society of India》2011,78(1):45-56
In Kameng Valley of Arunachal Pradesh, the crystalline rocks of Se La Group of Higher Himalaya are thrust over the Lesser
Himalayan rocks of Dirang Formation, Bomdila Group along the Main Central Thrust and exhibit well preserved structures on
macro- to microscopic scales. Detailed analysis of structures reveals that the rocks of the area have suffered four phases
of deformation D1, D2, D3 and D4. These structures have been grouped into (i) early structures (ii) structures related to progressive ductile thrusting and
(iii) late structures. The early structures which developed before thrusting formed during D1 and D2 phases of deformation, synchronous to F1 and F2 phases of folding respectively. The structures related to progressive ductile shearing developed during D3 phase of deformation, when the emplacement of the crystalline rocks took place over the rocks of Dirang Formation along the
Main Central Thrust. Different asymmetric structures/kinematic indicators developed during this ductile/brittle-ductile regime
suggest top-to-SSW sense of movement of the crystalline rocks of the area. D4 is attributed to brittle deformation. Based on satellite data two new thrusts, i.e. Tawang and Se La thrusts have been identified
parallel to Main Central Thrust, which are suggestive of imbricate thrusting. Strain analysis from the quartz grains of the
gneissic rocks reveals constriction type of strain ellipsoid where k value is higher near the MCT, gradually decreases towards
the north. Further, the dynamic analysis carried out on the mesoscopic ductile and brittle-ductile shear zones suggest a NNE-SSW
horizontal compression corresponding to the direction of northward movement of Indian Plate. 相似文献
849.
Vartika Singh Anjum Farooqui Naresh. C. Mehrotra Dhruv Sen Singh Rajni Tewari Neerja Jha Ratan Kar 《Journal of the Geological Society of India》2011,78(2):109-116
Subsurface sediments of a 120 cm deep trench from Ny-Alesund, Svalbard, were analysed for pollenspores and other organic matter
contents. This study is supported by two AMS 14C dates (27, 200 yrs BP and 8,762 yrs BP) at the bottom and topmost litho-unit of the trench, respectively. The pollen record
provides an evidence of a warm interval at about 27,200 yr BP (Late Weichselian and MIS 3) and cooling episode around 8,762
yr BP. This is also supported by the amount and type of organic matter as well as sediment type and depositional history of
the trench sediments. 相似文献
850.
The Ganga Plain is one of the most densely populated regions of the world due to its fertile soil and availability of water. The rivers of this plain are the lifeline for millions of people of this vast alluvial plain. All rivers of this plain are characterized by narrow channel confined within wide valley. Continuously increasing pressure of population on this plain has led to the intensification of settlement even into the valley of the river. This unplanned expansion has enhanced the damage due to flooding during high-discharge period and lateral erosion during low-discharge period. Flooding and lateral erosion are identified as fluvial hazards in the Ghaghara River area. Extensive studies have been carried out on flooding, but not much attention has been paid to the phenomenon of lateral erosion. However, it has been observed that lateral erosion is an independent fluvial hazard that operates during low-discharge period. Low degree of compaction due to the presence of sandy and silty facies in the river valley deposits, mass movement, palaeocurrent pattern, and fractures initiates and enhances the lateral erosion. The present paper deals with the fluvial hazards in the Ghaghara River area. 相似文献