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R. Saravanathamizhan N. Mohan N. Balasubramanian V. Ramamurthi C. Ahmed Basha 《洁净——土壤、空气、水》2007,35(4):355-361
In the present investigation, treatment of textile effluent using an electrochemical technique was designed and analyzed using the Box-Behnken method. The influence of individual parameters on electro-oxidation of textile effluent has been critically examined using the response surface method (RSM), and a quadratic model for chemical oxygen demand (COD) reduction has been developed. It has been observed from the present analysis that the predicted values are in good agreement with experimental data with a correlation coefficient of 0.945. 相似文献
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Sorptive removal of Ni(II) from electroplating rinse wastewaters by cation exchange resin Dueolite C 20 was investigated at the temperature of 30°C under dynamic conditions in a packed bed. The effects of sorbent bed length 0.1–0.2 m, fixed flow rate 6 dm3 min?1, and the initial rinse water concentration (C0) 53.1 mg L?1 on the sorption characteristics of Dueolite C 20 were investigated at an influent pH of 6.5. More than 94.5% of Ni(II) was removed in the column experiments. The column performance was improved with increasing bed height and decreasing the flow rate. The Thomas, Yoon–Nelson, Clark, and Wolborska models were applied to the experimental data to represent the breakthrough curves and determine the characteristic design parameters of the column. The sorption performance of the Ni(II) ions through columns could be well described by the Thomas, Yoon–Nelson, and Wolborska models at effluent‐to‐influent concentration ratios (C/C0) >0.03 and <0.99. Among the all models, the Clark model showed the least average percentage time deviation. The sorptive capacity of electroplating rinse water using Ni(II) was found to be 45.98 mg g?1. 相似文献
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M. Srinivasa Reddy Shaik Basha S. Adimurthy G. Ramachandraiah 《Estuarine, Coastal and Shelf Science》2006,68(3-4):656
This study aimed to assess the accumulation of small plastic debris in the intertidal sediments of the world's largest ship-breaking yard at Alang-Sosiya, India. Small plastics fragments were collected by flotation and separated according to their basic polymer type under a microscope, and subsequently identified by FT-IR spectroscopy as polyurethane, nylon, polystyrene, polyester and glass wool. The morphology of these materials was also studied using a scanning electron microscope. Overall, there were on average 81 mg of small plastics fragments per kg of sediment. The described plastic fragments are believed to have resulted directly from the ship-breaking activities at the site. 相似文献
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The paper pertains to the pseudo-static seismic stability analysis of reinforced soil structures. Using limit equilibrium
method and assuming the failure surface to be logarithmic spiral, analysis has been conducted to maintain internal stability
against both tensile and pullout failure of the reinforcements. The external stability of the reinforced earth wall is also
assessed in terms of its sliding, overturning, eccentricity and bearing modes of failure. The influence of the intensity of
the surcharge load placed on the backfill is also considered in the analysis. The obtained results are validated by comparing
the same with those reported in literature. Studies have also been made regarding the influence of backfill soil friction
angle, horizontal and vertical seismic accelerations, surcharge load, the tensile strength of reinforcement, pullout length
of the reinforcement and number of reinforcement layers on the seismic stability against various failure modes as mentioned
earlier. 相似文献
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A methodology for reliability based optimum design of reinforced soil structures subjected to horizontal and vertical sinusoidal excitation based on pseudo-dynamic approach is presented. The tensile strength of reinforcement required to maintain the stability is computed using logarithmic spiral failure mechanism. The backfill soil properties, geometric and strength properties of reinforcement are treated as random variables. Effects of parameters like soil friction angle, horizontal and vertical seismic accelerations, shear and primary wave velocities, amplification factors for seismic acceleration on the component and system probability of failures in relation to tension and pullout capacities of reinforcement have been discussed. In order to evaluate the validity of the present formulation, static and seismic reinforcement force coefficients computed by the present method are compared with those given by other authors. The importance of the shear wave velocity in the estimation of the reliability of the structure is highlighted. The Ditlevsen's bounds of system probability of failure are also computed by taking into account the correlations between three failure modes, which is evaluated using the direction cosines of the tangent planes at the most probable points of failure. 相似文献
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Distribution, enrichment and accumulation of heavy metals in coastal sediments of Alang-Sosiya ship scrapping yard, India 总被引：11，自引：0，他引：11
Reddy MS Basha S Sravan Kumar VG Joshi HV Ramachandraiah G 《Marine pollution bulletin》2004,48(11-12):1055-1059
Since its inception in 1982, the Alang-Sosiya yard has become the largest ship scrapping works in the world. Several hundreds of ships arrive every year. The degree of heavy metal contamination has been studied in bulk and fine sediments from the intertidal zone of this ship scrapping yard, two stations, one on either side at 5 km distance and one reference station 60 km distance near Mahuva, towards the south. The samples have been subjected to a total digestion technique and analysed for elements: Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, Zn and Al, and %TOC. The absolute metal concentrations reflected variations in BF and FF sediment samples with organic matter content. Enrichment factors (EF) and geoaccumulation indices (Igeo) have been calculated and the relative contamination levels are assessed at these sites. At Alang-Sosiya, the enrichment of heavy metals has been observed to be relatively high. 相似文献
8.
An intraplate earthquake of magnitude (M
c) 6.9 (Anon 2001a) struck Bhuj and the adjoining region of Kachchh in Gujarat on January 26th, 2001 at about 0316 hrs (GMT)
and was followed by a number of aftershocks. The epicentre of this earthquake was located at 23.4‡N and 70.28‡E close to the
Kachchh mainland fault. The intensity observed around the epicenter was X on the MSK scale. A study of 531 aftershocks, in
the magnitude range of 3.0–5.7, recorded at Vadodara Seismological Observatory till March 31st, 2001 has been carried out
and various statistical parameters calculated. The total energy released during the study period is calculated to be 8.2 ×
1014 joule. Sudden occurrence of the main shock without any foreshock in the same tectonic system is a unique feature of this
sequence. Theb- value (0.86), value of M0-M1 (1.2), high M1/M0 (0.89) and high value of the decay constanth (0.91), all support the tectonic origin of the present study. 相似文献
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Variation in sedimentology as well as freshwater and marine palynomorphs has been studied in ecological perspective in two 2.5‐ and 5‐m deep sediment cores deposited since 3440 and 3630 cal BP, respectively in the central part of Pichavaram mangrove wetland, Cauvery River delta. The palynological and sedimentological results of the sediments reveal a monsoonal circulation and a climatic shift from warm and humid with strengthened monsoon (3630–3190 cal BP) to dry and arid (~2750–760 cal BP). Since the last millennium (~760 cal BP), Pichavaram estuary has been influenced by a similar cyclicity but with a less wet and humid climate due to weakened monsoon conditions. These ecological changes in turn affect the relative sea level rise and fall which is reflected by the variability/extinction of freshwater and marine palynomorphs. The estuary remained an active water channel between ~3630 and 2750 cal BP, responding to the strengthened monsoon, during which the freshwater algal remains with thecamoebians and marine dinoflagellate cysts and foraminiferal linings both dominated with a ratio of 1.5 for marine/freshwater forms. After this period, since ~2750 cal BP there has been a dominance of marine forms with a ratio of 4.5 for marine/freshwater forms, indicating fluvio‐marine sediment deposition and suggesting the recent landward intrusion of seawater during weakened monsoon conditions. Freshwater thecamoebians are vulnerable to the salinity >3 in the aqueous soil solution of estuarine sediment, and therefore serve as an excellent proxy for monitoring salinity gradient along with short‐term high resolution palaeoecological fluctuations induced by climate and relative sea‐level changes in an estuarine ecosystem. 相似文献
10.
The present paper develops an analytical approach to the problem of heat-induced moisture movement in the vicinity of a spherical heat source embedded in an undeformable, moist porous solid of infinite extent. A transient-state distribution of temperature within the infinite medium is assumed to induce the moisture transport process. The numerical results, presented in the paper, illustrate the influence of the moisture transport characteristics on the time-dependent distribution of moisture within the porous medium. © 1998 John Wiley & Sons, Ltd. 相似文献