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61.
Chandravir Narayan 《Chemistry and Ecology》2016,32(6):533-549
In recent decades, the Sal-dominated tropical deciduous forests (TDFs) were experiencing loss of regeneration due to lack of seed germination of native species. To understand this ecological problem, the present study dealt with the spatial and temporal variations in biogeochemical parameters of Sal forest soils. Twenty soil samples were collected from four TDF sites in the Chota Nagpur Plateau, India. The inventories of tree species in three life-cycle stages (seedling, sapling and adult) were carried out in four sites. Site-I (290?stems?ha?1) showed occurrence of only one species (Shorea robusta) without seedling and sapling. The pH of forest soils was acidic to slightly acidic in nature. Seasonal variations in C/N ratio showed rapid mineralization of organic matter in the rainy season. ANOVA revealed that the degree of seasonal variation caused significant difference in pH, soil organic carbon, soil organic matter, total carbon, Al, Fe, Ca, Mg, Mn and P across four sites. The strong correlation of P with pH, Al, Fe, Mg and Mn indicated highly oxidised and exchangeable nature of dry forest soils. Factor analysis of soil parameters revealed that the different combinations of edaphic conditions in different seasons were important in the distribution of the dry tropical forests communities in Chota Nagpur Plateau. 相似文献
62.
Transport phases of four metals of geochemical and water quality importance were investigated in rivers around Jamshedpur. The metals iron, manganese, zinc and copper were partitioned into dissolved, adsorbed and or ion exchangeable, solid organic, oxide coating and crystalline phases applying filtration for the dissolved phase and a chemical fractionation scheme for the particulates. Iron and copper were transported mainly in the particulate phases at all sites, while manganese and zinc were found in the dissolved phase up to a hundred percent depending on the pH of water sample and pollution at the site concerned. Except copper more than 75 percent of all other three metals occurred in transport modes thought to be available to aqueous and biotic interactions. Copper was in available phases from 50 to 70 percent. The significance of metal partitioning as a factor in controlling metal availability and toxicity to biota is discussed. 相似文献
63.
Narayan R Saxena KK Chauhan S 《Journal of environmental biology / Academy of Environmental Biology, India》2007,28(1):155-157
Present investigations were carried out on the limnological aspects of Texi temple pond in district Etawah. Many of the parameters were found below the permissible limits for drinking water as suggested by WHO. A total of 18 parameters were analysed and their seasonal variations in the year 2003 were discussed. 相似文献
64.
65.
Consumer crash test programs provide comparative information on the crashworthiness of new vehicles which, in turn, should predict the performance of the same vehicles in real-world crashes. However, the detail and quality of available information from tests and real-world crashes differ widely, so identifying meaningful relationships between crash test results and real-world crashworthiness can be difficult. Despite these data limitations, studies in the late 1980s and mid-1990s reported positive correlations between dummy injury measures from the U.S. New Car Assessment Program (USNCAP) and real-world fatality rates. More recent analyses of results from Australian crash tests and real-world crashes also have found positive correlations. This article considers relationships between recent U.S. frontal crash test results from the Insurance Institute for Highway Safety (IIHS) and USNCAP, and real-world crash injury risk estimates computed from police-reported crash data from three U.S. states. The frontal crash test results include dummy injury measures by body region from both IIHS offset tests and USNCAP full-width barrier tests plus measures of structural performance from the IIHS offset tests. Individually, results from the full-width and offset tests were not significantly correlated with the real-world injury risk estimates. Stronger relationships were found when a combination of overall ratings from the full-frontal and offset tests was used. However, the current results find only weak correlations between both full-front and offset frontal crash test performance and the real-world injury risk estimates. These weak relationships likely reflect the lack of detail and fundamental difference in injury information in police crash reports compared to that used in deriving crashworthiness ratings from the crash tests. 相似文献
66.
Farm forestry is a very minor land use in the inland agricultural landscapes of Australia. The Australian Government intends to introduce a program to encourage landholders to trade the carbon sequestration value of plantations and this may change the relative profitability of plantations against other agricultural land uses. This research compares the returns from a timber and ‘carbon’ plantation, with those from grazing and a common crop rotation in the Kingaroy area of Queensland.Typical production patterns for all systems were developed from producer and expert knowledge and soil and vegetation sampling were used to estimate sequestration rates. The costs and benefits of all land use systems were converted into monetary terms and discounted to produce net present values. With a standard discount rate and average commodity prices based on recent history, cultivation is the most profitable option, followed by pasture and plantations. After the inclusion of carbon, plantations are the most profitable option, followed by pasture and cultivation. A number of qualifications of these findings are also discussed. 相似文献
67.
Hashim MA Mukhopadhyay S Sahu JN Sengupta B 《Journal of environmental management》2011,92(10):2355-2388
The contamination of groundwater by heavy metal, originating either from natural soil sources or from anthropogenic sources is a matter of utmost concern to the public health. Remediation of contaminated groundwater is of highest priority since billions of people all over the world use it for drinking purpose. In this paper, thirty five approaches for groundwater treatment have been reviewed and classified under three large categories viz chemical, biochemical/biological/biosorption and physico-chemical treatment processes. Comparison tables have been provided at the end of each process for a better understanding of each category. Selection of a suitable technology for contamination remediation at a particular site is one of the most challenging job due to extremely complex soil chemistry and aquifer characteristics and no thumb-rule can be suggested regarding this issue. In the past decade, iron based technologies, microbial remediation, biological sulphate reduction and various adsorbents played versatile and efficient remediation roles. Keeping the sustainability issues and environmental ethics in mind, the technologies encompassing natural chemistry, bioremediation and biosorption are recommended to be adopted in appropriate cases. In many places, two or more techniques can work synergistically for better results. Processes such as chelate extraction and chemical soil washings are advisable only for recovery of valuable metals in highly contaminated industrial sites depending on economical feasibility. 相似文献
68.
Verma Sarika Mili Medha Dhangar Manish Jagatheesan Krishnasamy Paul Sriparna Bajpai Harsh Vedanti Nimisha Mallik Jyotirmoy Khan Mohammed Akram Bhargaw Hari Narayan Hashmi Sayed Azhar Rasheed Srivastava Avanish Kumar 《Environmental science and pollution research international》2021,28(46):64929-64950
Environmental Science and Pollution Research - The materials used in electrical and electronic applications have great importance and broader applications, but they have severe electromagnetic... 相似文献
69.
Srirangam Kumaresan Narayan Yoganandan Frank A. Pintar Wade M. Mueller 《Traffic injury prevention》2013,14(2):87-101
The objective of the present study was to develop three separate age-specific one, three, and six year old pediatric human cervical spine (C4-CS-C6) three-dimensional nonlinear finite element models and to quantify the biomechanical responses. The adult model was modified to create one, three, and six year old pediatric spines by incorporating the local geometrical and material characteristics of the developmental anatomy. The adult human cervical spine model was constructed from close-up computed tomography sections and sequential anatomic cryomicrotome sections, and validated with experimental data. The biomechanical responses were compared with the adult human cervical spine behavior under different loading modes using three approaches. Approach 1: using pure overall structural scaling (reduce size) of the adult model. Approach 2: using three separate age-specific pediatric models incorporating local component geometrical and material property changes. Approach 3: applying the overall structural scaling to the above three pediatric models. All pediatric structures were consistently more flexible than the adult spine under all loading modes. However, responses obtained using the pure overall structural scaling (Approach 1) increased the flexibilities slightly. In contrast, the inclusion of local component geometrical and material property changes to create the three individual pediatric cervical spine models (Approach 2) produced significantly higher changes in the flexibilities under all loading modes. When overall structural scaling effects were added to the three pediatric models (Approach 3), the increase was not considerably higher. White the one year old pediatric model was the most flexible followed by the three and six year old models in flexion and extension, the three year old pediatric model was the most flexible under compression followed by the six and one year old models. The differing biomechanical responses among different pediatric groups were ascribed to the individual developmental anatomical features. The present findings of significant increase in biomechanical response due to local geometry and material property changes emphasize the need to consider the developmental anatomical features in the pediatric structures to better predict their biomechanical behavior. 相似文献
70.
D. A. Plummer J. C. McConnell L. Neary J. Kominski R. Benoit J. Drummond J. Narayan V. Young D. R. Hastie 《Atmospheric environment (Oxford, England : 1994)》2001,35(36):240
An aircraft-based measurement campaign was conducted during the summer of 1996 in the vicinity of Toronto, Canada. The objective of the campaign was to assess the errors in a particular emission inventory used by three-dimensional air quality models. Measurements of NO2 and hydrocarbons were made both upwind and downwind of Toronto, on days with strong synoptic-scale flow from a west to northerly direction. The chemical composition of the background airmass on these days was typical of unpolluted continental air. Measurements have been compared with the output from an on-line air quality model (MC2-AQ) run at 5 km resolution and suggest that emissions of NOx from Toronto are well described in the emission database, though evidence that NOx emissions are underestimated for suburban regions surrounding Toronto was found. In general, no significant underestimation of hydrocarbon emissions was found, though emissions of the model propane species, which includes acetylene and benzene, was underestimated by at least a factor of two. 相似文献