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51.
Scientific literature discussed various types of mixture models and models derived from maximum entropy principle using short-term wind speed data for their relative assessment. The literature on suitability of these mixture models for long-term data is rarely available. However, for correct assessment of wind power potential both wind speed and wind direction are equally important. Therefore, in this paper, both wind speed and wind direction are simultaneously analyzed using several types of mixture distribution and compared the same with conventional Weibull distribution. For wind speed and wind power density assessment, the mixture distributions such as Weibull--Weibull distribution, Gamma--Weibull distribution, Truncated Normal--Weibull distribution, Truncated Normal--Normal distribution, proposed Truncated Normal--Gamma distribution and Gamma--Gamma distribution along with MEP-distribution are compared with conventional 2-parameter Weibull distribution. Similarly, for wind direction analysis, the finite mixtures of von-Mises distribution are compared with conventional von-Mises distribution. Judgment criteria include R2, RMSE, Kolmogorov--Smirnov test and relative percentage error in wind power density. The sites selected are the three onshore locations of India, viz., Calcutta, Trivandrum, and Ahmedabad. The results show that for wind speed assessment, mixture distribution performs better than the conventional Weibull distribution for analyzing wind power density. However, location wise comparison of all mixture distribution is of prime importance. For wind direction analysis, finite mixture of two von-Mises distributions proved to be a suitable candidate for Indian climatology. 相似文献
52.
A study was conducted in the residential areas of Delhi, India, to assess the variation in ambient air quality and ambient
noise levels during pre-Diwali month (DM), Diwali day (DD) and post-Diwali month during the period 2006 to 2008. The use of
fireworks during DD showed 1.3 to 4.0 times increase in concentration of respirable particulate matter (PM10) and 1.6 to 2.5 times increase in concentration of total suspended particulate matter (TSP) than the concentration during
DM. There was a significant increase in sulfur dioxide (SO2) concentration but the concentration of nitrogen dioxide (NO2) did not show any considerable variation. Ambient noise level were 1.2 to 1.3 times higher than normal day. The study also
showed a strong correlation between PM10 and TSP (R
2 ≥ 0.9) and SO2 and NO2 (R
2 ≥ 0.9) on DD. The correlation between noise level and gaseous pollutant were moderate (R
2 ≥ 0.5). The average concentration of the pollutants during DD was found higher in 2007 which could be due to adverse meteorological
conditions. The statistical interpretation of data indicated that the celebration of Diwali festival affects the ambient air
and noise quality. The study would provide public awareness about the health risks associated with the celebrations of Diwali
festival so as to take proper precautions. 相似文献
53.
Ashis Bhattacharjee Haradhan Mandal Madhusudan Roy Joachim Kusz Maciej Zubko 《Environmental monitoring and assessment》2014,186(11):7399-7411
Physical aspects of tobacco samples, used in some commonly available Indian brands of cigarettes, with emphasis on their magnetic characterization before and after they get burnt into ashes, are described. The present work highlights the ultrafine nature of the cigarette ashes and provides a compositional insight of their constituent particulate matters as revealed by the XRD and SEM studies. Based on the EDX spectra, elemental distributions of different tobacco samples, before and after they get burnt, are presented. In this work, magnetic measurements of the un-burnt tobacco samples are reported. An attempt is made to shed light on the origin of magnetism observed in these samples. 相似文献
54.
K. K. Sharma Irani Mukherjee Balwinder Singh Kousik Mandal Sanjay K. Sahoo Hemanta Banerjee Tirthankar Banerjee Sankhajit Roy Paresh G. Shah Hemlatta K. Patel Anil R. Patel S. Naseema Beevi Thomas George Thomas B. Mathew Geeta Singh Rajbir Noniwal Sunita Devi 《Environmental monitoring and assessment》2014,186(12):8453-8461
Supervised field trials were conducted at four different agro-climatic locations of India to evaluate the dissipation pattern and risk assessment of spiromesifen on tomato. Spiromesifen 240 SC was sprayed on tomato at 150 and 300 g a.i.?ha?1. Samples of tomato fruits were drawn at 0, 1, 3, 5, 7, 10 and 15 days after treatment and soil at 15 days after treatment. Quantification of residues was done on gas chromatograph–mass spectrophotometer in selective ion monitoring mode in the mass range of 271–274 (m/z). The limit of quantification of the method was found to be 0.05 mg kg?1, while the limit of determination was 0.015 mg kg?1. Residues were found below the LOQ of 0.05 mg kg?1 in 10 days at both the doses of application at all the locations. Spiromesifen dissipated with a half-life of 0.93–1.38 days at the recommended rate of application and 1.04–1.34 days at the double the rate of application. Residues of spiromesifen in soil were detectable level (<0.05 mg kg?1) after 15 days of treatment. A preharvest interval (PHI) of 1 day has been recommended on tomato on the basis of data generated under All India Network Project on Pesticide Residues. Spiromesifen 240 SC has been registered for its use on tomato by Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of spiromesifen on tomato has been fixed by Food Safety Standard Authority of India, Ministry of Health and Family Welfare, Government of India as 0.3 μg/g after its risk assessment. 相似文献
55.
Proper assessment of air quality status in an atmosphere based on limited observations is an essential task for meeting the goals of environmental management. A number of classification methods are available for estimating the changing status of air quality. However, a discrepancy frequently arises from the quality criteria of air employed and vagueness or fuzziness embedded in the decision making output values. Owing to inherent imprecision, difficulties always exist in some conventional methodologies like air quality index when describing integrated air quality conditions with respect to various pollutants parameters and time of exposure. In recent years, the fuzzy logic-based methods have demonstrated to be appropriated to address uncertainty and subjectivity in environmental issues. In the present study, a methodology based on fuzzy inference systems (FIS) to assess air quality is proposed. This paper presents a comparative study to assess status of air quality using fuzzy logic technique and that of conventional technique. The findings clearly indicate that the FIS may successfully harmonize inherent discrepancies and interpret complex conditions. 相似文献
56.
S. K. Sharma A. Datta T. Saud T. K. Mandal Y. N. Ahammed B. C. Arya M. K. Tiwari 《Environmental monitoring and assessment》2010,162(1-4):225-235
We present diurnal variation of ambient ammonia (NH3) in relation with other trace gases (O3, CO, NO, NO2, and SO2) and meteorological parameters at an urban site of Delhi during winter period. For the first time, ambient ammonia (NH3) was monitored very precisely and continuously using ammonia analyzer, which operates on chemiluminescence method. NH3 estimation efficiency of the chemiluminescence method (>90%) is much higher than the conventional chemical trapping method (reproducibility 4.5%). Ambient NH3 concentration reaches its maxima (46.17 ppb) at night and minimum during midday. Result reveals that the ambient ammonia (NH3) concentration is positively correlated with ambient NO (r 2?=?0.79) and NO2 (r 2?=?0.91) mixing ratio and negatively correlated with ambient temperature (r 2?=???0.32). Wind direction and wind speed indicates that the nearby (~500 m NW) agricultural fields may be major source of ambient NH3 at the observational site. 相似文献
57.
Soil enzymes are indicators of microbial activities in soil and are often considered as an indicator of soil health and fertility. They are very sensitive to the agricultural practices, pH of the soil, nutrients, inhibitors and weather conditions. To understand the effect of an insecticide, thiamethoxam, on different soil enzyme activities, the experiments were conducted at cotton experimental fields of Punjab Agricultural University, Ludhiana. The results here were presented to understand the impact of thiamethoxam on soil enzyme activities. Thiamethoxam was applied as seed treatment to control the pest. Soil from three localities, i.e. soil in which seed was treated with recommended dose at 2.1 g a.i. kg?1, soil in which seed was treated with four times recommended dose at 8.4 g a.i. kg?1 and from the control field, were tested for different enzyme activities. Phosphatase and dehydrogenase activities were high in control soil in comparison to control soil while no effect of this insecticide on urease activity. Thiamethoxam had inhibitory effects on dehydrogenase and phosphatase activities. Therefore, it can be attributed that agricultural practices, weather conditions and use of thiamethoxam might be responsible for the different level of enzyme activities in soil. 相似文献
58.
Soft-bottom macrobenthic diversity and community structure were assessed at Mumbai and Jawaharlal Nehru ports during three different periods between 2001 and 2002 (November 2001 post-monsoon 1, April/May 2002 pre-monsoon, and October 2002 post-monsoon 2). A total of 43 macrobenthic invertebrate species belonging to five phyla were recorded. Macrofaunal abundance (PM1 186, PreM 106, and PM2 31 ind m?2) and species diversity index (PM1 0.87, PreM 0.73, and PM2 0.30) were very low in all the seasons. Polychaetes were the most dominant macrobenthic group (72.09%) followed by decapoda, amphipoda, and bivalves (4.56%). Canonical correspondence analysis showed that sediment texture, temperature, and suspended particulate matter were the most important environmental variables influencing polychaete species composition. Significant seasonal variations were observed, influenced by dissimilar monsoonal patterns. Macrobenthic population density during November 2001 was higher than that of October 2002 post-monsoon season. Pre-monsoon season recorded more carnivorous polychaete species than post-monsoon seasons. The present study showed lower values of polychaete diversity index in all the seasons compared to earlier studies. Out of 31 polychaete species, 19 have been reported for the first time from this area. Polychaete species and Glycera longipinnis, Paraprionospio pinnata, and Cossura coasta recorded from 1985 to 1986 were also observed in the present study. Species like Sigambra constricta, Perinereis cavifrons, Prionospio polybranchiata, and Parheteromastus tenuis were not recorded in the present study, although they were observed during earlier studies in this area. 相似文献
59.
S. K. Sahoo Kousik Mandal Gurmail Singh Rajinder Kumar G. S. Chahil R. S. Battu Balwinder Singh 《Environmental monitoring and assessment》2013,185(2):1711-1718
Quizalofop ethyl, a phenoxy propionate herbicide, is used for postemergence control of annual and perennial grass weeds in broad-leaved crops in India. The experiments were designed to study the dissipation kinetics of quizalofop ethyl on onion for two seasons. A simple, rapid, and sensitive method for estimation of quizalofop ethyl residues in onion and soil was developed and validated. The recoveries of quizalofop ethyl residues from onion and soil at different spiking level range from 84.81 to 92.68 %. The limit of quantification of this method was found to be 0.01 μg g?1. The risk assessment through consumption of the onion in comparison to its acceptable daily intake which is an important parameter for the safety of the consumer was also evaluated. Standardized methodology supported by recovery studies was adopted to estimate residues of quizalofop ethyl on onion and soil. The average initial deposits of quizalofop ethyl on onion were observed to be 0.25 and 0.33 mg kg?1, following single application of the herbicide at 50 g active ingredient (a.i.) ha?1 during 2009 and 2010, respectively. The half-life values (T 1/2) of quizalofop ethyl on onion crop were worked out to be 0.85 and 0.79 days, respectively, during 2009 and 2010. At harvest time, the residues of quizalofop ethyl on onion and soil were found to be below the determination limit of 0.01 mg kg?1 following single application of the herbicide at 50 and 100 g a.i. ha?1 for both the periods. 相似文献
60.
Sarika Gupta Ranu Gadi T.K. Mandal S.K. Sharma 《Environmental monitoring and assessment》2017,189(1):43
Delhi is one of the most polluted cities in the world. The generation of aerosols in the lower atmosphere of the city is mainly due to a large amount of natural dust advection and sizable anthropogenic activities. The compositions of organic compounds in aerosols are highly variable in this region and need to be investigated thoroughly. Twenty-four-hour sampling to assess concentrations of n-alkanes (ng/m3) in PM10 was carried out during January 2015 to June 2015 at Indira Gandhi Delhi Technical University for Women (IGDTUW) Campus, Delhi, India. The total average concentration of n-alkanes, 243.7 ± 5.5 ng/m3, along with the diagnostic tools has been calculated. The values of CPI1, CPI2, and CPI3 for the whole range of n-alkanes series, petrogenic n-alkanes, and biogenic n-alkanes were 1.00, 1.02, and 1.04, respectively, and C max were at C25 and C27. Diagnostic indices and curves indicated that the dominant inputs of n-alkanes are from petrogenic emissions, with lower contribution from biogenic emissions. Significant seasonal variations were observed in average concentrations of n-alkanes, which is comparatively higher in winter (187.4 ± 4.3 ng/m3) than during the summer season (56.3 ± 1.1 ng/m3). 相似文献