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141.
Kanha Gupta Nitin Khandelwal Gopala Krishna Darbha 《Frontiers of Environmental Science & Engineering》2020,14(1):15
142.
143.
Karanja oil, containing 6.2% free fatty acids (FFAs), was considered for biodiesel production using a single-step solid-phase acid catalyzed process. Different types of zeolites and Amberlyst15 catalysts were tested and biodiesel was produced. Under similar conditions, the highest biodiesel yield was achieved using an Amberlyst15 catalyst, which contained 3–5% of moisture. The effects of operating parameters of the reaction such as reaction temperature, catalyst amount, and methanol-to-oil ratio were studied. An increase of methanol:oil ratio revealed a non-monotonic increase in biodiesel yields. Similar non-monotonic behavior was observed when Jatropha oil was used. Leaching and catalyst reusability were also considered. No significant effects of leaching were observed and catalyst reusability appeared to be affected by methanol interactions. The presence of a co-solvent, Tetrahydrofuran (THF), increased the biodiesel yield. Furthermore, an optimum amount of THF (THF:methanol volume ratio of 1:2) gave rise to the highest biodiesel yield. A biodiesel yield of 93% was achieved at 120 °C using a single-step process with Amberlyst15 as a catalyst, THF as a co-solvent, and a methanol:oil ratio of 30:1. 相似文献
144.
Suman Gupta R. K. Sharma V. T. Gajbhiye R. K. Gupta 《Environmental monitoring and assessment》2013,185(3):2107-2114
Persistence of cypermethrin, deltamethrin, profenofos, and triazophos in cauliflower curd was studied, following application of two premix formulations viz: Roket 44EC (profenofos 40 % + cypermethrin 4 %) and Anaconda Plus 36EC (triazophos 35 % + deltamethrin 1 %) at recommended (1.0 L ha?1) and double doses (2.0 L ha?1). In the case of Roket 44EC, residues of cypermethrin dissipated with the half-life values of 1.5–2.1 days, whereas residues of profenofos dissipated with the half-life of 2.9–3.3 days on cauliflower curd. In the case of Anaconda, residues of triazophos and deltamethrin dissipated from curd with the half-life values of 2.6–3.0 and 2.2–2.6 days, respectively. Both the combination mix significantly reduced the aphid population up to 14 days after spray and increased the yield by 155–160 % over control. Anaconda (2.0 L ha?1) treated plots yielded the highest number of marketable curds. Based on risk assessment analysis, safe waiting period of 3 and 5 days has been suggested for Roket 44EC and Anaconda Plus 36EC, respectively, in cauliflower at recommended dose of application. 相似文献
145.
Duttagupta S Gupta S Gupta A 《Journal of environmental biology / Academy of Environmental Biology, India》2004,25(3):369-373
Red blooms of Euglena sp. in the floodplain wetland ecosystems of Barak Valley, Assam, India, were found to be induced by high concentrations of NH3-N, NO3, Fe, Mg and to some extent, PO4, Cu and Zn in their water. The trace elements were rapidly accumulated by the bloom organisms to high levels, whereby their concentrations in the water declined, leading to a collapse of the bloom, which tended to reappear as decomposition again led to the release of the nutrients. The bloom also harboured fairly high density of certain other algae and zooplankton, thereby acting as a sub-system within the wetland ecosystem. The bloom is non-toxic and is exploited as a fish food by the fish-farmers who artificially induce a bloom for augmenting the growth of surface-feeding species of fishes. 相似文献
146.
Joshi N Gupta D 《Journal of environmental biology / Academy of Environmental Biology, India》2008,29(2):211-214
2, 4-dichlorophenoxyacetic acid (2,4-D) is a post emergence herbicide. The tests were conducted to study the toxicity of 2,4-D using EC50 value in four dilutions. 2,4-D was applied at concentration of 25, 50, 75, 100, 200 and 300 mg l(-1) in the potato Dextrose agar medium. The effect of this herbicide was evaluated as the colony forming unit (CFU). EC50 value for 10(-3) dilution of soil was 138 +/- 5.944 mg l(-1). Soil physico-chemical parameters and mycofloral properties were also evaluated. Qualitatively 10 genera of fungi were observed in untreated soil, whereas 4 genera were found in 2,4-D administered dose. 相似文献
147.
Gupta DK Rai UN Tripathi RD Sinha S Rai P Inouhe M 《Journal of environmental biology / Academy of Environmental Biology, India》2005,26(3):539-546
Phytochelatins and related metabolites (cysteine and GSH) were found to be induced in the shoots of two varieties of Cicer arietinum viz., CSG-8962 and C-235 grown under different amendments of fly-ash with garden soil and press mud. Cysteine, GSH, PCs and its speciation were found in higher concentrations in amended fly-ash than in the control 100% soil. Two species of metal binding peptides i.e., PC2 and PC4 were found in both varieties and in amendments, however, their concentration varied depending upon the fly-ash concentrations in both amendments. Further, var. CSG-8962 was found more tolerant than var. C-235 because of higher concentrations of PCs and related metabolites. 相似文献
148.
G. D. Martin P. A. Nisha K. K. Balachandran N. V. Madhu M. Nair P. Shaiju T. Joseph K. Srinivas G. V. M. Gupta 《Environmental monitoring and assessment》2011,176(1-4):427-438
The influence of anthropogenic loading on the distribution of soft bottom benthic organisms of a tropical estuary (Cochin backwaters) was examined. The industrial activities were found to be high in the northern and central part of the estuary, where dissolved inorganic nitrogen (DIN > 210 ??M) and phosphorus (DIP > 6.5 ??M) have caused high abundance of chlorophyll a (up to 73 mg m???3) and accumulation of organic carbon in sediments (up to 5%). Principal component analysis distinguished three zones in the estuary. The central zone (Z1) was characterized by organic enrichment, low species diversity, and increased number of pollution tolerant species. Long-term deterioration of the estuary is indicated by an increase in the nutrients and chlorophyll a levels by sixfold during the last few decades. Flow restrictions in the lower estuary have lead to a fourfold increase in sediment organic carbon over the period of three decades. The reduced benthic diversity followed by an invasion of opportunistic polychaetes (Capitella capitata), are indicative of a stress in the estuary. 相似文献
149.
Ajit Kumar Verma Suresh Kumar Gupta Rajendra Kumar Isaac 《Environmental Modeling and Assessment》2014,19(1):45-55
Soil–Water–Atmosphere–Plant (SWAP) version 2.0 was evaluated for its capability to simulate crop growth and salinity profiles at Agra (India) located in a semi-arid region having deep water table and monsoon climate. The data of 12 conjunctive use treatment combinations simulating cyclic and mixing modes of fresh and saline water for wheat were used to calibrate and validate the model. Absolute deviations between the SWAP simulated and observed relative yields during calibration ranged from 2.5 to 2.9 %. A close agreement in the trend and values of measured and simulated soil salinity profiles was observed. Scenario building simulations carried out with the validated SWAP revealed that the maximum crop yields varied from 97 to 99 % with the best available water (EC 3.6 dS m?1) while the minimum ranged from 65 to 79 % in the treatment with all saline water. Other than this, the relative yield varied from 80 to 98 % in 10 other cyclic and mixing mode treatments. It was established that notwithstanding the seasonal build-up of salts due to saline water use, there would be no long-term build-up of salts as leaching during the monsoon season would render the soil profile salt free at the time of sowing of rabi (winter) crops. Thus, short-term field observations could be used in conjunction with SWAP to show that there seems to be an assured long-term sustainability when saline water is used in conjunctive mode with fresh water in monsoon climatic conditions with deep water table. These results are in conformity with the observation that many farmers in India are using saline and fresh water in conjunctive mode on a long-term basis. 相似文献
150.
Shivnam Rana Vikas Jindal Kousik Mandal Gurpreet Kaur V. K. Gupta 《Environmental monitoring and assessment》2015,187(5):300
Twelve bacterial species were evaluated to know the degradation pattern of thiamethoxam in liquid medium. All the bacterial species could actively degrade phorate in a mineral salt medium containing phorate (50 μg ml–1) as sole carbon source. As these species have ability to degrade, we used these for the degradation of thiamethoxam—a neonicoitinoids. Screening of 12 active phorate-metabolizing bacterial species resulted in selection of Bacillus aeromonas strain IMBL 4.1 and Pseudomonas putida strain IMBL 5.2 causing 45.28 and 38.23 % thiamethoxam (50 μg ml?1) reduction, respectively, in 15 days as potential thiamethoxam degrading species. These two bacterial species grew optimally at 37 °C under shake culture conditions in MSMT medium raised with initial pH of 6.0–6.5 and use of these optimum cultural conditions resulted in improved thiamethoxam degradation by these bacterial species. These species caused maximum thiamethoxam degradation only in the presence of thiamethoxam as sole source of carbon and energy and the same was reduced in the presence of easily metabolize able carbon (C0 and C1) and nitrogen ((N0, N1 and N2) sources. This could be attributed to involvement of repressible metabolic pathways, reactions of which are inhibited by the presence of easily available nutrients for growth. Besides above, qualitative analysis of thiamethoxam residues by gas liquid chromatography revealed complete metabolization of thiamethoxam without detectable accumulation of any known thiamethoxam metabolites. 相似文献