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排序方式: 共有207条查询结果,搜索用时 31 毫秒
1.
Rahul Ray Deepak Kumar Pijush Samui Lal Bahadur Roy A.T.C.Goh Wengang Zhang 《地学前缘(英文版)》2021,12(1):375-383
This research focuses on the application of three soft computing techniques including Minimax Probability Machine Regression(MPMR),Particle Swarm Optimization based Artificial Neural Network(ANN-PSO)and Particle Swarm Optimization based Adaptive Network Fuzzy Inference System(ANFIS-PSO)to study the shallow foundation reliability based on settlement criteria.Soil is a heterogeneous medium and the involvement of its attributes for geotechnical behaviour in soil-foundation system makes the prediction of settlement of shallow a complex engineering problem.This study explores the feasibility of soft computing techniques against the deterministic approach.The settlement of shallow foundation depends on the parametersγ(unit weight),e0(void ratio)and CC(compression index).These soil parameters are taken as input variables while the settlement of shallow foundation as output.To assess the performance of models,different performance indices i.e.RMSE,VAF,R^2,Bias Factor,MAPE,LMI,U(95),RSR,NS,RPD,etc.were used.From the analysis of results,it was found that MPMR model outperformed PSO-ANFIS and PSO-ANN.Therefore,MPMR can be used as a reliable soft computing technique for non-linear problems for settlement of shallow foundations on soils. 相似文献
2.
In this study radar, surface observations and numericalsimulations are used to examine the inland penetrationand intensity of the sea breeze during various large-scaleflow regimes along the curved coastline of the Carolinas,U.S.A. The results clearly indicate that the flow directionrelative to the curved coastline has a significant effecton the sea-breeze evolution.Overall, during northerly flow regimes alongthe curved North Carolina coast, observationsand numerical simulations show that the sea-breezefront has a tendency to remain close to the south-facingcoast. During these same flow regimes the frontmoves further inland relative to the east-facingcoast. The sea-breeze front during westerly flowcases progressed further inland relative to the southcoast and less so from the east-facing coastline.South-westerly flow allows the sea breeze to moveinland from both coastlines but the coastal shapeinfluence makes the inland penetration less fromthe easterly facing beaches. During periods of lightonshore flow (south-east), the sea breeze movesconsiderable distances inland but is not discernableuntil later in the afternoon. The simulations indicatedthat the sea-breeze intensity is greatest (least) when thelarge-scale flow direction has an offshore (onshore)component. Model results indicate the existence of astrong front well inland in the late afternoon duringlight onshore flow. Also noted was that the simulatedsea-breeze front develops earlier in the afternoon duringoffshore regimes and later in the day as the large-scaleflow becomes more onshore. It is concluded that thecoastline shape and coast-relative flow direction areimportant factors in determining how the sea-breezecirculation evolves spatially. 相似文献
3.
Shan Huang Ankit Garg Guoxiong Mei Disheng Huang Rahul Balaji Chandra Shaji Gayathri Sadasiv 《水文研究》2020,34(23):4512-4525
Biochar has the potential to be a soil amendment in green roofs owing to its water retention, nutrient supply, and carbon sequestration application. The combined effects of biochar and vegetated soil on hydraulic performance (e.g., saturated hydraulic conductivity, retention and detention, and runoff delay) are the crucial factor for the application of the novel biochar in green roofs. Recent studies investigated soil water potential (i.e., suction) either on vegetated soil or on biochar-amended soil but rarely focused on their integrated application. With the purpose of investigating the hydraulic performance of green roofs in the application of biochar, the combined effect of biochar and vegetated soil on hydrological processes was explored. Artificial rainfall experiments were conducted on the four types of experimental soil columns, including natural soil, biochar-amended soil, vegetated natural soil, and vegetated biochar-amended soil. The surface ponding, bottom drainage and the volumetric water content were measured during the rainfall test. Simulation method by using HYDRUS-1D was adopted for estimating hydraulic parameters and developing modelling analysis. The results indicated that the saturated hydraulic conductivity of vegetated soil columns were higher than bare soil columns. The addition of biochar decreased the saturated hydraulic conductivity, and the magnitude of decrease was much significant in the case of vegetated soil. The influence of vegetation on permeability is more prominent than biochar. The vegetated biochar-amended soil has the highest retention and detention capacity, and shows a preferable runoff delay effect under heavy rain among the four soil columns. The results from the present study help to understand the hydrological processes in the green roof in the application of biochar, and imply that biochar can be an alternative soil amendment to improve the hydraulic performance. 相似文献
4.
N. Prakash A. Garg 《International Journal of Environmental Science and Technology》2016,13(11):2675-2688
In the present study, the effectiveness of physicochemical treatment processes (coagulation and Fenton’s oxidation) was investigated for simulated dairy wastewater (pH = 7.3, chemical oxygen demand (COD) = 3600 mg/l, 5-day biochemical oxygen demand (BOD5) = 1950 mg/l, total Kjeldahl nitrogen (TKN) = 87 mg/l, and total phosphorous (TP) = 14 mg/l). Plain and ballasted coagulation runs were carried out in a jar apparatus, while Fenton’s oxidation was performed in a three-neck glass reactor. Ballasted coagulation caused an enhancement in the settling rate of sludge though no significant enhancement in the removal of organics was observed. Individually, coagulation and Fenton’s oxidation processes resulted in ~67 and 80 % COD removals, respectively, from the wastewater. The sequential treatment exploring coagulation followed by Fenton’s oxidation showed overall COD, BOD5, TKN, and TP reductions of ~93, 97, 84, and 70 %, respectively, from the wastewater. However, a biological post-treatment would be required to achieve the effluent discharge standards. The removal of proteins, fats, and amino acids from wastewater was confirmed from Fourier transform infrared analysis of the settled sludge (obtained after coagulation process). Preliminary cost analysis suggested coagulation and the sequential treatment (i.e. coagulation followed by Fenton’s oxidation) as the preferred options. 相似文献
5.
6.
Rahul Sharma S. Jai Sankar Sudeshna Samanta A. A. Sardar D. Gracious 《Geo-Marine Letters》2010,30(6):617-626
Factors such as non-uniform illumination of seafloor photographs and partial burial of polymetallic nodules and crusts under
sediments have prevented the development of a fully automatic system for evaluating the distribution characteristics of these
minerals, necessitating the involvement of a user input. A method has been developed whereby spectral signatures of different
features are identified using a software ‘trained’ by a user, and the images are digitized for coverage estimation of nodules
and crusts. Analysis of >20,000 seafloor photographs was carried out along five camera transects covering a total distance
of 450 km at 5,100–5,300 m water depth in the Central Indian Ocean. The good positive correlation (R2 > 0.98) recorded between visual and computed estimates shows that both methods of estimation are highly reliable. The digitally
computed estimates were ∼10% higher than the visual estimates of the same photographs; the latter have a conservative operator
error, implying that computed estimates would more accurately predict a relatively high resource potential. The fact that
nodules were present in grab samples from some locations where photographs had nil nodule coverage emphasises that nodules
may not always be exposed on the seafloor and that buried nodules will also have to be accounted for during resource evaluation.
When coupled with accurate positioning/depth data and grab sampling, photographic estimates can provide detailed information
on the spatial distribution of mineral deposits, the associated substrates, and the topographic features that control their
occurrences. Such information is critical for resource modelling, the selection of mine sites, the designing of mining systems
and the planning of mining operations. 相似文献
7.
The present paper deals with the inhibition of the specific activity of the acid and alkaline phosphatases in the kidney tissue of mudskipper Boleophthalmus dentatus, exposed to different sublethal concentrations of mercuric chloride. There was a more or less linear inhibition of the specific activity of both the enzymes with increasing concentration of mercuric chloride as well as exposure time. The inhibition of acid phosphatase could be due to the rupture of lysosomal membrane in the presence of mercury compound, which acts as a labilizing agent. The inhibition of alkaline phosphatase probably caused a breakdown of the membrane transport system. 相似文献
8.
Closed form analytic expressions for displacement and stresses at any point of either of the two homogeneous, isotropic, perfectly
elastic half-spaces in welded contact due to very long strike-slip dislocations are obtained. Both cases of vertical and horizontal
strike-slip dislocations are discussed in detail. Variation of the displacement with horizontal distance from the fault and
with vertical distance from the interface for a vertical strike-slip fault is studied numerically. 相似文献
9.
Dev Niyogi Hsin-I Chang Fei Chen Lianhong Gu Anil Kumar Surabi Menon Roger A. Pielke Sr. 《Natural Hazards》2007,42(2):345-359
Aerosols can affect the cloud-radiation feedback and the precipitation over the Indian monsoon region. In this paper, we propose
that another pathway by which aerosols can modulate the multi-scale aspect of Indian monsoons is by altering the land–atmosphere
interactions. The nonlinear feedbacks due to aerosol/diffuse radiation on coupled interactions over the Indian monsoon region
are studied by: (1) reviewing recent field measurements and modeling studies, (2) analyzing the MODIS and AERONET aerosol
optical depth datasets, and (3) diagnosing the results from sensitivity experiments using a mesoscale modeling system. The
results of this study suggest that the large magnitude of aerosol loading and its impact on land–atmosphere interactions can
significantly influence the mesoscale monsoonal characteristics in the Indo-Ganges Basin. 相似文献
10.
The Rann ingress into the ‘Banni Plains’ of Kachchh district, Gujarat which is famous for the sprawling grasslands supporting significant cattle population is taking place at an alarming rate. This has resulted in the desertion of many villages due to intrusion of Rann waters. In the present investigation multi-date satellite data has been analysed to map and monitor the Rann ingress during the period 1975 to 1989. Detailed analysis has brought out that the inundation is quite rapid affecting about 244 sq. km area during 1960–1989 period. Mapping of the creeks has also been done to understand the possible mechanism of ‘Rann ingress’. 相似文献