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71.
P. K. Govil J. E. Sorlie D. Sujatha A. K. Krishna N. N. Murthy K. Rama Mohan 《Environmental Earth Sciences》2012,66(1):121-128
Spatial distribution and temporal trends studies were carried out at Katedan Industrial Development Area (KIDA) near Hyderabad,
capital of Andhra Pradesh state, India under Indo-Norwegian Institutional Cooperation Program, to find out the extent of contamination
in streams and lake sediments from the discharge of industrial effluents. Stream and lake sediment samples were collected
from the five lakes in the study area and connecting water streams. The samples were analyzed by XRF spectrometer for toxic
elements. The studies reveal that the stream sediments with in the KIDA and the impounded Noor Mohammed Lake down stream have
high concentration of some of the toxic elements like chromium, nickel, lead, arsenic, zinc etc. The geology of the area indicates
that the study area consists of residual soil of acidic rocks, which are predominantly of Archaean gneisses and granites having
low to medium concentrations of chromium and nickel. The source of these high concentration of elements like lead 2,300 mg/kg,
copper 1,500 mg/kg, arsenic 500 mg/kg, chromium 500 mg/kg etc. cannot be derived from the surrounding acidic rocks and may
be attributed to the industrial effluents released in the ditches and random dumping of hazardous solid waste. It was observed
that the metal concentrations increased in the streams during the dry season (pre-monsoon period). After the monsoon rains,
the metal concentrations in the streams were reduced by half which may be due to dilution. The eroded sediments are deposited
in the lake where very high concentrations were encountered. Overflowing of the lake will spread the contamination further
downstream. The lake sediments will remain as a major source of contamination by desorption to the water phase regardless
of what happens to the effluent discharge in the KIDA. However, some samples showed enrichment of lead, arsenic and nickel
during post-monsoon, which were collected near the dumpsite due to the leaching of toxic elements from the dump site to the
lakes. Some of the toxic elements like nickel and copper have not shown any dilution but have increased after the rains, which
could be due to the leaching of arsenic from the dumpsite to the lake along with rainwater. Geochemical maps showing the distribution
of heavy/trace elements in streams and lakes are prepared and presented in this paper. Effect of toxic elements on the health
of the residents in the surrounding residential areas is also discussed. 相似文献
72.
Vijay Mohan Bhatnagar 《Contributions to Mineralogy and Petrology》1969,22(4):375-378
High-precision, computer-refined values of the cell parameters of calcium hydroxyapatite, Ca10(PO4)6(OH)2, have been determined with an X-ray diffractometer, internally standardized by means of sodium chloride. The results obtained are as follows: a
0=9.4192 Å c
0/a
0=0.731 c
0=6.8867 Å volume=529.2 Å3
The apatite work was supported by a research grant DE-02105 from the United States Department of Health, Education, and Welfare. I am very grateful to Dr. W. R. Liebenberg, Dr. S. A. Hiemstra and Dr. H. V. R. von Rahden of National Institute for Metallurgy, South Africa for their valuable help and interest and Prof. Nelson Fuson and Prof. James R. Lawson for advice and discussion. 相似文献
73.
This paper presents the creep behaviour of intact and remoulded specimens of fibrous peat obtained from a field site near Anzac, Alberta, Canada. The creep behaviour was investigated by means of long-term drained and undrained triaxial tests. The development of volumetric, axial, and undrained axial strain and strain rate during drained and undrained creep tests under variable stress conditions is presented. The stress – strain – strain rate (p′–ε v–\(\dot{\varepsilon }_{\text{v}}\)) relationship is found to be unique for different stress and loading durations. The p′–ε v–\(\dot{\varepsilon }_{\text{v}}\) relationship is analysed and represented by creep isotaches. The applicability of different creep models developed for normally consolidated clay is discussed and applied to define the development of creep strain in fibrous peat under varying isotropic and deviator stresses. The secondary consolidation coefficient for evaluating the volumetric strain rate of peat is found to be applicable with some limits. The drained creep behaviour of remoulded peat specimens differs from the behaviour shown by Shelby tube specimens, whereas the undrained creep behaviour in remoulded and Shelby tube specimens is similar. 相似文献
74.
Mark D. Bateman Tim C. Kinnaird Jon Hill Robert A. Ashurst Jenna Mohan Rebecca B. I. Bateman Ruth Robinson 《Boreas: An International Journal of Quaternary Research》2021,50(4):1059-1078
The Storegga tsunami, dated in Norway to 8150±30 cal. years BP, hit many countries bordering the North Sea. Run-ups of >30 m occurred and 1000s of kilometres of coast were impacted. Whilst recent modelling successfully generated a tsunami wave train, the wave heights and velocities, it under-estimated wave run-ups. Work presented here used luminescence to directly date the Storegga tsunami deposits at the type site of Maryton, Aberdeenshire in Scotland. It also undertook sedimentological characterization to establish provenance, and number and relative power of the tsunami waves. Tsunami model refinement used this to better understand coastal inundation. Luminescence ages successfully date Scottish Storegga tsunami deposits to 8100±250 years. Sedimentology showed that at Montrose, three tsunami waves came from the northeast or east, over-ran pre-existing marine sands and weathered igneous bedrock on the coastal plain. Incorporation of an inundation model predicts well a tsunami impacting on the Montrose Basin in terms of replicate direction and sediment size. However, under-estimation of run-up persisted requiring further consideration of palaeotopography and palaeo-near-shore bathymetry for it to agree with sedimentary evidence. Future model evolution incorporating this will be better able to inform on the hazard risk and potential impacts for future high-magnitude submarine generated tsunami events. 相似文献
75.
A case study of atmospheric boundary layer features during winter over a tropical inland station — Kharagpur (22.32°N, 87.32°E) 总被引:1,自引:0,他引:1
Denny P. Alappattu P. K. Kunhikrishnan Marina Aloysius M. Mohan 《Journal of Earth System Science》2009,118(4):281-293
The local weather and air quality over a region are greatly influenced by the atmospheric boundary layer (ABL) structure and
dynamics. ABL characteristics were measured using a tethered balloon-sonde system over Kharagpur (22.32°N, 87.32°E, 40m above
MSL), India, for the period 7 December 2004 to 30 December 2004, as a part of the Indian Space Research Organization-Geosphere
Biosphere Program (ISRO-GBP) Aerosol Land Campaign II. High-resolution data of pressure, temperature, humidity, wind speed
and wind direction were archived along with surface layer measurements using an automatic weather station. This paper presents
the features of ABL, like ABL depth and nocturnal boundary layer (NBL) depth. The sea surface winds from Quikscat over the
oceanic regions near the experiment site were analyzed along with the NCEP/NCAR reanalysis winds over Kharagpur to estimate
the convergence of wind, moisture and vorticity to understand the observed variations in wind speed and relative humidity,
and also the increased aerosol concentrations. The variation of ventilation coefficient (V C), a factor determining the air pollution potential over a region, is also discussed in detail. 相似文献
76.
Net-pen aquaculture results in the introduction of excess fish food and fecal matter in coastal waters. These wastes may modify the benthic environment. Mathematical models are developed in this study to simulate tidal and wind-driven currents, waves, and the resulting dispersion of fish food and fecal matter in coastal Maine, a region where limited modelling studies have been performed. Cobscook Bay and Toothacher Bay in Maine are studied in detail through the use of mathematical models and field data. We find that a systematic, site-specific, step-by-step modeling strategy involving the use of numerical models to simulate the overall hydrodynamic environment in combination with a waste-particle transport model can be an extremely powerful method of determining a priori whether aquaculture operations will cause high rates of net-pen waste accumulation at a particular site. 相似文献
77.
Geological and geochemical study has been carried out to investigate arsenic contamination in groundwater in Nawalparasi, the western Terai district of Nepal. The work carried out includes analyses of core sediments, provenance study by rare earth elements analyses, 14C dating, and water analyses. Results showed that distribution of the major and trace elements are not homogeneous in different grain size sediments. Geochemical characteristics and sediment assemblages of the arsenic contaminated (Nawalparasi) and uncontaminated (Bhairahawa) area have been compared. Geochemical compositions of sediments from both the areas are similar; however, water chemistry and sedimentary facies vary significantly. Extraction test of sediment samples showed significant leaching of arsenic and iron. Chemical reduction and contribution from organic matter could be a plausible explanation for the arsenic release in groundwater from the Terai sediments. 相似文献
78.
正1研究目的(Objective)自2011年在四川南部地区下古生界海相地层中获得页岩气工业性突破以来,在四川盆地进行的海相页岩气开发得到多方的重视和迅速发展,随之而来的是人们对页岩气勘探开发过程中对环境影响的关注。页岩气,它以吸附或游离状态为主要方式赋存于富有机质泥页岩及其夹层中,是一种非常规天然气。与常规天然气相比,页岩气气质优良,甲烷含量更高。页岩气化学成分主要为甲烷(CH4),一般含量在85%以上,最高达到99.8%,另外还含有少量的乙烷(C2H6)、丙烷(C3H8)和丁烷(C4H10)。一般认为我国页岩气中可以存在少量氮 相似文献
79.
We present values of velocity of ground water percolation (Vg) over large depth intervals, varying from shallow to deeper depths in Indaram area of Godavari sub-basin. The velocities have been estimated using available measured geothermal data. Sub-surface temperatures were measured in seven boreholes. Terrestrial heat flow values are calculated using temperature data and measured values of thermal conductivity of core samples. The results show that Vg is ~3.4 ×10?7 cm /sec in the top layers (70–150 m) and decreases to ~0.04×10?7 cm/sec in the deeper levels around 350 m depth and becomes negligibly small thereafter, thereby, indicating that the overall permeability of the sub-surface layers, due to the occurrence of successions of permeable, semi-permeable layers gets reduced to more or less zero at depths around 350 m. The value of Thermal Peclet Number, which is the ratio of the heat transfer through convection to that through conduction, naturally becomes negligible around this depth in the area. The observed consistency of the magnitude of heat flow through various deep sections is a clear indicator that water percolation is practically reduced to zero at depths around 320–400 m and that conduction is the dominant mechanism of heat transfer below the inferred depth section, while the upper layers are dominated by recharge at various depths by near surface water from streams at Indaram. 相似文献
80.
G. Suresh S. H. Wankhade Mohamed Shareef Vivek P. Malviya Binod Kumar M. Mohan 《Journal of the Geological Society of India》2013,81(2):151-157
A meteorite shower occurred in Katol (21° 15′ 30″ N; 78° 35′ 00″ E; at an elevation of 415 m above msl), Nagpur district of Maharashtra state, India on May 22, 2012 between 14:00 to 14:30 hrs (Indian Standard Time) with a presently observed strewn field of ~5.0 sq km area. The event was experienced by the hundreds of inhabitants with a loud noise and fire ball between Akola in the west to Nagpur in the east. The Geological Survey of India has so far collected 27 meteorite pieces with a total weight of 3500 gm. The locations, size, shape and surface features of the individual meteorite pieces have been recorded. Based on their physical properties, mineralogy, mineral chemical mapping and REE chemistry, the Katol meteorites have been classified as olivine-rich H5 type differentiated stony meteorite with reconstituted chondrules. The preliminary evidence suggests the presence of pre-solar grains in Katol meteorite. 相似文献