排序方式： 共有13条查询结果，搜索用时 62 毫秒
1.
2.
M. Vijayakumaran R. Venkatesan T. Senthil Murugan T.S. Kumar Dilip Kumar Jha M.C. Remany 《新西兰海洋与淡水研究杂志》2013,47(2):623-634
Pueruli and post‐pueruli, early juveniles and sub‐adults of the spiny lobster, Panulirus homarus and juveniles of P. ornatus were grown in different floating sea cages along the southeast coast of India from May 2003 to May 2007. The first type of cage had a galvanised iron pipe frame (2.0 m × 2.0 m × 1.2 m) with steel woven mesh and four inner detachable compartments (0.75 m × 0.75 m × 1.10 m). Fibre‐reinforced plastic was used subsequently to fabricate cages (1 m × 1 m × 1 m). Pueruli and post‐pueruli of P. homarus (1.58 ± 0.62 g SD), stocked at 60 individuals/m2, grew to an average weight of 123.10 ± 26.22 g in 266 days with a survival rate of 70%. Sub‐adults of P. homarus with an average weight (± SD) of 123.61 ± 29.26 g reached 341.25 ± 46.22 g in 225 days at a stocking density of 21 individuals/m2 with a survival of 73 ± 6%. The post‐pueruli grew by 0.46 ± 0.10 g per day with a specific growth rate (SGR) of 1.64, whereas sub‐adults had a growth rate of 0.97 ± 0.20 g per day with a SGR of 0.43. At a higher stocking density of 80 individuals/m2, juveniles (51.83 ± 10.32 g and 58.20 ± 28.22 g) of P. homarus recorded growth rates of 0.86 ± 0.25 (SGR 0.82) and 0.97 ± 0.34 g (SGR 0.96) per day. This study indicates that post‐pueruli of P. homarus can be grown to over 200 g in 12 months and up to 350 g in 16 to 17 months in sea cages. Juveniles (average weight 76.35 ± 34.50 g) of P. ornatus, reared with P. homarus at a stocking density of 80 individuals/m2, recorded a weight gain of 139 g in 155 days at arate of 0.89 ± 0.32 g per day with an SGR of 0.67. Marine live clam, Donax spp., was the main feed supplemented with the gastropod, Xancus pyrum, the green mussel, Perna viridis, marine crab (Charibdis sp.), squid (Loligo sp.), and fish such as clupeids and Leognathus sp. Pueruli and post‐pueruli settled in large numbers (up to 35 individuals/month in one cage) both inside and outside the cages. 相似文献
3.
Muthusamy Murugan Paddu Krishnappa Shetty Raju Ravi Aavudai Anandhi Arulappan Joseph Rajkumar 《Climatic change》2012,110(3-4):737-753
In this study we analyzed climate and crop yields data from Indian cardamom hills for the period 1978–2007 to investigate whether there were significant changes in weather elements, and if such changes have had significant impact on the production of spices and plantation crops. Spatial and temporal variations in air temperatures (maximum and minimum), rainfall and relative humidity are evident across stations. The mean air temperature increased significantly during the last 30?years; the greatest increase and the largest significant upward trend was observed in the daily temperature. The highest increase in minimum temperature was registered for June (0.37°C/18?years) at the Myladumpara station. December and January showed greater warming across the stations. Rainfall during the main monsoon months (June–September) showed a downward trend. Relative humidity showed increasing and decreasing trends, respectively, at the cardamom and tea growing tracts. The warming trend coupled with frequent wet and dry spells during the summer is likely to have a favorable effect on insect pests and disease causing organisms thereby pesticide consumption can go up both during excess rainfall and drought years. The incidence of many minor pest insects and disease pathogens has increased in the recent years of our study along with warming. Significant and slight increases in the yield of small cardamom (Elettaria cardamomum M.) and coffee (Coffea arabica), respectively, were noticed in the recent years.; however the improvement of yield in tea (Thea sinensis) and black pepper (Piper nigrum L.) has not been seen in our analysis. 相似文献
4.
P. Divyalakshmi D. Murugan M. Sivarajan A. Sivasamy P. Saravanan C. L. Rai 《International Journal of Environmental Science and Technology》2017,14(4):813-822
Excess sludge generation is a major problem in biological effluent treatment processes. Utilization of excess sludge for gas production is an attractive route, which could be enhanced by pretreatment methods. This study involves two sets of experiments. The first set covers mechanical pretreatment of both feed and inoculum. The second set involves alkaline and mechanical treatments of feed and only mechanical treatment of inoculum. Response surface methodology was used for experimental design, analysis and optimization. The optimized mechanical treatment volume of feed was found to be 50%. Diligent mechanical treatment of inoculum resulted in enhanced microbial activity and improved gas production. Reduction in volatile solids, proteins and carbohydrates was observed to a maximum of 63, 84 and 78.5%, respectively. Feed was subjected to alkali treatment in order to reduce mechanical energy input and to improve solubilization. Compared to mechanical treatment alone, enhanced gas production of about 15% was observed at an optimized pH of 11.8 and SRT of 21 days. A biokinetic model was formulated, simulated and validated for the degradation of organics and gas production. 相似文献
5.
6.
Influence of hydrogeochemical processes on temporal changes in groundwater quality in a part of Nalgonda district, Andhra Pradesh, India 总被引：4，自引：3，他引：1
Geochemical processes that take place in the aquifer have played a major role in spatial and temporal variations of groundwater
quality. This study was carried out with an objective of identifying the hydrogeochemical processes that controls the groundwater
quality in a weathered hard rock aquifer in a part of Nalgonda district, Andhra Pradesh, India. Groundwater samples were collected
from 45 wells once every 2 months from March 2008 to September 2009. Chemical parameters of groundwater such as groundwater
level, EC and pH were measured insitu. The major ion concentrations such as Ca2+, Mg2+, Na+, K+, Cl−, and SO4
2− were analyzed using ion chromatograph. CO3
− and HCO3
− concentration was determined by acid–base titration. The abundance of major cation concentration in groundwater is as Na+ > Ca2+ > Mg2+ > K+ while that of anions is HCO3
− > SO4
2− > Cl− > CO3
−. Ca–HCO3, Na–Cl, Ca–Na–HCO3 and Ca–Mg–Cl are the dominant groundwater types in this area. Relation between temporal variation in groundwater level and
saturation index of minerals reveals the evaporation process. The ion-exchange process controls the concentration of ions
such as calcium, magnesium and sodium. The ionic ratio of Ca/Mg explains the contribution of calcite and dolomite to groundwater.
In general, the geochemical processes and temporal variation of groundwater in this area are influenced by evaporation processes,
ion exchange and dissolution of minerals. 相似文献
7.
8.
S.Selvam P.Muthukumar Sruthy Sajeev S.Venkatramanan S.Y.Chung K.Brindha D.S.Suresh Babu R.Murugan 《地学前缘(英文版)》2021,12(1):29-38
The present study focused on the estimation of submarine groundwater discharge(SGD)and the effects of nutrient fluxes due to the SGD process.The parameters of SGD such as magnitude,character,and nutrient flux in Punnakayal region of South East coast of India were evaluated using multiple tracers of groundwater inputs in 2019.It was found that the elevated values for the tracers in the study area,displayed a gradational change in the values as move from estuarine part to the offshore.Simultaneous occurrence of fresh and saline SGD is observed on the study sites.Also,indicated that the SGD fluxes ranged from 0.04 to 0.12 m^3 m^-2d^-1 at the estuary and0.03-0.15 m^3 m^-2d^-1at the groundwater site.A substantially increased value for 222 Rn activities is distinguished in the estuary to values over 312 dpm L^-1.Nutrient embellishments were generally greatest at locations with substantial meteoric elements in groundwater;however,the recirculation of saltwater through the geological formation could provide a way of transferring terrestrially-derived nutrients to the coastal zone at many places. 相似文献
9.
A. K. Dwivedi U. K. Pandey C. Murugan A. K. Bhatt P. V. Ramesh Babu Mallikarjun Joshi 《Journal of the Geological Society of India》2011,77(6):527-538
The Barabazar granite, exposed at the northern margin of Singhbhum craton, Eastern India, occurs along the South Purulia Shear
Zone (SPSZ) and is emplaced into the Palaeoproterozoic metapelites and felsic volcanics of Singhbhum Group. Geochemical, petrographical
and geochronological studies on the Barabazar granite addressed in the work have wide implications on understanding the geodynamics
of SPSZ during Palaeoproterozoic to Mesoproterozoic. Geochemically, Barabazar granite displays limited range of major oxides,
alkali enrichment and highly fractionated features (SiO2 > 75%; Eu/Eu* = 0.16–0.33; enrichment of K, Rb, Th, U and Nb; depletion of Ba, Sr, P and Ti). It is predominantly peraluminous
(molar Al2O3/CaO+Na2O+K2O (A/CNK) =1.14–144) and contains abundant alkali feldspar, perthite, and minor plagioclase, biotite and accessory minerals.
Geochemical and petrological data indicates that it is A-type granite, which formed in ‘Within plate granite’ tectonic set
up. The Barabazar granite was emplaced at ca. 1771 Ma (Pb-Pb) in rift related environs and evolved by partial melting of stabilized
lower/middle crust (initial 87Sr/86Sr = 0.7302 ± 0.0066 and μ1 = 8.5 ± 0.5). Subsequently, the shear zone (SPSZ) developed during the closure of the riftogenic basin and was reactivated
during the Grenvillian orogeny (Ca. 900–1300 Ma), resulting in rehomogenisation of the strontium isotopes and thereby yielding
younger whole-rock Rb-Sr isotope age of c. 971 Ma for the Barabazar granite. Probably during this tectonic event, the Singhbhum
craton (Southern India Shield) would have finally juxtaposed with Northern Indian Shield along Central Indian Tectonic Zone
(CITZ) during the global Grenvillian orogeny. 相似文献
10.
A. V. Murugan Suresh Kumar V. K. Dadhwal M. K. Gupta 《Journal of the Indian Society of Remote Sensing》2014,42(2):453-459
This study involves generation and logical integration of non-spatial and spatial data in a geographical information system framework to address the gap in national level soil organic carbon estimates. Remote sensing derived inputs and other spatial layers are corrected and integrated using same geographical standards. A relational data base of soil organic carbon density of Indian forest was prepared with attribute information. Hierarchical approach was followed to stratify and verify each sample from the data base using the corrected input layers in GIS and the resulting spatially distributed data is called Indian forest soil organic carbon database. The estimated mean soil organic carbon density for Indian forest is 70 t ha?1 and varied from 35.4 t ha?1 in Tropical thorn forest to 104.2 t ha?1 in Himalayan moist temperate forest in the upper 30 cm of soil depth. Due to large variations in the surface layers the estimated standard error ranged from ±1.5 to 15 % for the upper 30 cm layer which is generally higher than the bottom soil layers. The level of detail in the data base helps to establish base line information for global, national and regional level studies. 相似文献