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201.
In this work, we investigate one-dimensional solute transport affected by rate-limited sorption, first-order mass transfer, and first-order transformation. Analytical expressions are obtained for the temporal moments of the solute in the solution phase. The effect of various rate coefficients on the temporal moments is examined. It was found that, in the presence of transformation reactions, the mean arrival time, and the spread and skewness of the breakthrough curves, are not monotonic functions of the rate coefficients. These solutions will be useful as a preliminary analysis tool for ascertaining the relative importance of various processes under given conditions. They may also be used to analyze the accuracy of various numerical techniques used for simulation of reactive transport. 相似文献
202.
Oral administration of 0.7 mg/kg/day of quinalphos to mals buffalo calves for 28 consecutive days produced marked inhibition of erythrocyte acetylcholinesterase and elevation in serum levels of aminotransferases and phosphatases without inducing apparent toxicity. The enzymic alterations were more pronounced following 1.4 and 2.1 mg/kg/day doses of quinalphos, which were lethal within 4–17 days. 相似文献
203.
204.
In the present study total 21 forest stands on different aspects and locations (Hill base, mid slope and ridge top) on the
slope were studied to assess the importance of these two parameters in supporting species regeneration and biodiversity in
a mixed broadleaved forest between 380 and 850 m elevation in the Kumauau Himalayan region. A total of 36 tree species were
recorded in the forest. In all aspects the tree, sapling and shrub richness was higher at hill base stands in comparison to
mid slope and ridge top stand. Maximum tree richness (average across all aspects) was 9.7 and shrub richness was 9.3. Higher
richness at hill base may be attributed to more soil moisture and deeper soils which accumulate the hill base where the slope
steepness declines. The tree richness was higher in the northern aspect whereas southern aspect was more suitable for the
shrub species. From the present study it becomes evident that the base of the hills can support higher biodiversity and are
instrumental in supporting regeneration of several tree and shrub species in sal mixed broadleaved forest. 相似文献
205.
The ability of free and polysulphone immobilized biomass of Arthrobacter sp. to remove Cu2+ ions from aqueous solution was studied in batch and continuous systems. The Langmuir and Freundlich isotherm models were applied to the data. The Langmuir isotherm model was found to fit the sorption data indicating that sorption was monolayer and uptake capacity (Qo) was 175.87 and 158.7 mg/g for free and immobilized biomass respectively at pH 5.0 and 30 °C temperature, which was also confirmed by a high correlation coefficient, a low RMSE and a low Chi-square value. A kinetic study was carried out with pseudo-first-order reaction and pseudo-second-order reaction equations and it was found that the Cu2+ uptake process followed the pseudo-second-order rate expression. The diffusivity of Cu2+ on immobilized beads increased (0.402 × 10−4 to 0.435 × 10−4 cm2/s) with increasing concentration from 50 to 150 mg/L. The maximum percentage Cu2+ removal (89.56%) and uptake (32.64 mg/g) were found at 3.5 mL/min and 20 cm bed height. In addition to this the Bed Depth Service Time (BDST) model was in good agreement with the experimental data with a high correlation coefficient (>0.995). Furthermore, sorption and desorption studies were also carried out which showed that polysulphone immobilized biomass could be reused for up to six sorption–desorption cycles. 相似文献
206.
Present study explored the adsorptive characteristics of Indigo Carmine (IC) dye from aqueous solution onto rice husk ash (RHA). Batch experiments were carried out to determine the influence of parameters like initial pH (pH(0)), contact time (t), adsorbent dose (m) and initial concentration (C(0)) on the removal of IC. The optimum conditions were found to be: pH(0)=5.4, t=8h and m=10.0 g/l. The pseudo-second-order kinetic model represented the adsorption kinetics of IC on to RHA. Equilibrium isotherms were analyzed by Freundlich, Langmuir, Temkin and Redlich-Peterson models using a non-linear regression technique. Adsorption of IC on RHA was favorably influenced by an increase in the temperature of the operation. The positive values of the change in entropy (DeltaS(0)) and heat of adsorption (DeltaH(0)); and the negative value of change in Gibbs free energy (DeltaG(0)) indicate feasible and spontaneous adsorption of IC on to RHA. 相似文献
207.
Leaf surface structure alterations due to particulate pollution in some common plants 总被引:3,自引:0,他引:3
The plant foliar surface is the most important receptor of atmospheric pollutants. It undergoes several structural and functional
changes when particulate-laden air strikes it. In the present investigation, ten annual plant species viz., Abelmoschus esculentus, Celosia cristata, Coleus blumei, Cyamopsis tetragonolobus, Gomphrena globosa, Impatiens balsamina, Ocimum sanctum, Phaseolus vulgaris, Solanum melongena, and Zinnia elegans were studied for their growth parameters and leaf morphological features. They were subjected to dust experimentally for
60 days. The micro-morphological traits like wax, cuticle, epidermis, stomata, and trichomes were observed under light and
scanning electron microscopes. Remarkable differences in the growth parameters and micro-morphological features were recorded
in the dust-treated plants when compared to the respective controls. The reduction in growth parameters, the size of epidermal
cells, and stomata were reduced and cuticle damage was also observed. The relative proportion of fine particles, which play
a major role in hampering the overall growth of a plant, was higher in comparison to ultra-fine and coarse particles. 相似文献
208.
Gupta DK Tripathi RD Rai UN Mishra S Srivastava S Dwivedi S Maathuis FJ 《Environmental monitoring and assessment》2007,134(1-3):479-487
Growth and metal accumulation were investigated in two Cicer arietinum L. varieties (var. CSG-8962 and var. C-235) when grown in various combinations of fly ash (FA) amended with garden soil (GS),
press mud (PM) or saw dust (SD). In addition, the levels of photosynthetic pigments, nitrate reductase (NR) activity, cysteine,
non-protein thiols (NP-SH), and ascorbic acid were studied. FA amended with GS or PM led to a 5–10 times increase in biomass
compared to FA control and was most pronounced in the less metal tolerant variety CSG-8962. Amendment of FA with either GS
or PM only moderately increased the contents of some essential metals whereas the non-essential Cd and Cr remained similar
or decreased slightly compared to FA control. FA combined with either GS or PM increased the amount of photosynthetic pigments
and was largely absent when SD was added to FA. Improved nitrogen availability led to increased nitrate reductase (NR) activity
with all amendments but less so with SD. Metal stress indicating parameters were generally reduced (cysteine and non-protein
thiols) or unchanged (ascorbic acid). In conclusion, of the tested ameliorants both GS and PM greatly improved growth of C. arietinum making FA a suitable component of plant growth substrates. 相似文献
209.
Vethamony P Sudheesh K Babu MT Jayakumar S Manimurali R Saran AK Sharma LH Rajan B Srivastava M 《Environmental pollution (Barking, Essex : 1987)》2007,148(2):438-444
An oil spill occurred off Goa, west coast of India, on 23 March 2005 due to collision of two vessels. In general, fair weather with weak winds prevails along the west coast of India during March. In that case, the spill would have moved slowly and reached the coast. However, in 2005 when this event occurred, relatively stronger winds prevailed, and these winds forced the spill to move away from the coast. The spill trajectory was dominated by winds rather than currents. The MIKE21 Spill Analysis model was used to simulate the spill trajectory. The observed spill trajectory and the slick area were in agreement with the model simulations. The present study illustrates the importance of having pre-validated trajectories of spill scenarios for selecting eco-sensitive regions for preparedness and planning suitable response strategies whenever spill episodes occur. 相似文献
210.
The present study was performed under natural environment to assess levels of different heavy metals in soil and Abelmoschus esculentus plants along with soil microbial population irrigated with five rates of distillery effluent (DE) viz. 10, 25, 50, 75 and 100 % concentration in comparison with control (Bore well water). Results revealed that among various concentrations of DE, irrigation with 100 % DE significantly (P < 0.001) increased Zn (+63.46 %), Cu (+292.37 %), Zn (+3763.63 %), Cd (+264.29 %), Ni (+48.39 %) and Cr (+815.74 %), while decreased total bacteria (?45.23 %), fungi (?17.77 %) and actinomycetes (?42.57 %) in the soil. Enrichment factor of various heavy metals for soil was in the order Ni > Cr > Cd > Zn > Cu, and for A. esculentus plants, it was in the order Ni > Cr > Cu > Cd > Zn after irrigation with distillery effluent. The enrichment factor value was found maximum for Ni in comparison to other metals at 100 % DE concentration as compared with BWW. However, the values of these metals were below the recommended permissible limit. 相似文献