排序方式： 共有36条查询结果，搜索用时 31 毫秒
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海洋污损生物附着是增加海上作业成本、影响设施安全和缩短其使用年限的重要因素,掌握海洋污损生物幼虫和孢子的采集与培养技术是开展防除研究工作的基础。网纹藤壶Balanus reticulatus、缘管浒苔Enteromorpha linza、石莼Ulva lactuca和细基江蓠Gracilaria tenuistipitata是华南沿海主要的污损生物种类。研究上述4种污损生物幼虫和孢子的采集与培养技术,结果显示,网纹藤壶无节幼虫于30℃黑暗环境中培养,5d左右即可发育为金星幼虫,可将其在4℃条件下储存备用。强度为4000lx的光照射缘管浒苔和石莼,可刺激其游孢子大量释放;细基江蓠经阴干处理再浸泡海水,可诱导其果孢子的放散。每天接受900—1300lx光照12h,室温(21—26℃)下培养4d,是观察缘管浒苔和石莼游孢子附着萌发的最佳条件,而细基江蓠果孢子的附着萌发观察则以室温(18—23℃)下培养2d为宜。 相似文献
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Ali Akbar Daya 《Journal of the Geological Society of India》2014,83(5):567-576
Most significant iron ore deposits in Iran are located in Central Iran Zone. These deposits belong to the Bafq mining district. The Bafq mining district is located in the Early Cambrian Kashmar-Kerman volcanic arc of Central Iran. Linear estimation of regionalized variables (for example by inverse distance weighting or ordinary Kriging) results in relatively high estimation variances, i.e. the estimates have very low precision. Assessment of project economics (or other critical decision making) based on linear estimation is therefore risky. Non-linear estimation methods like disjunctive kriging perform better and the lower estimation variance allows less risky economic decision-making. Another advantage of disjunctive kriging is that it allows estimation of functions of the primary variable, which here is the grade (Fe %) of the ore. In particular it permits estimation of indicator functions defined using thresholds on the primary variable. This paper is devoted to application of disjunctive kriging method in Choghart North Anomaly iron ore deposit in Central Iran, Yazd province, Iran. In this study, the Fe concentration of Choghart North Anomaly iron ore deposit was modelled and estimated. The exploration data consists of borehole samples measuring the Fe concentration. A Gaussian isofactorial model is fitted to these data and disjunctive kriging was used to estimate the regionalized variable (Fe %) at unsampled locations and to assess the probabilities that the actual concentrations exceed a threshold value at a given location. Consequently a three dimensional model of probability of exceeding a threshold value and the estimated value are provided by disjunctive kriging to divide the ore into an economic and uneconomic part on the basis of estimation of indicator functions using thresholds grades defined on point support. The tools and concepts are complemented by a set of computer programs that are applied to the case study. The study showed that disjunctive kriging can be applied successfully for modeling the grade of an ore deposit. Results showed that the correlation between the estimated value and real value at locations close to each other is 81.9%. 相似文献
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B. Simhadri Rao M. Shanker V. Venkateswar Rao 《Journal of the Indian Society of Remote Sensing》2012,40(3):447-456
Availability of Water resources is not uniform in space and time resulting in deficient and surplus areas. In India, the idea of interlinking of river is proposed for many years to transfer water from surplus regions to water deficient areas. Ken-Betwa river link proposes to transfer 659 MCM of surplus waster from Ken basin to Betwa basin in order to utilise for irrigation and water supply by constructing new projects. Before taking up any new projects feasibility assessment studies are essential. In this context, satellite remote sensing plays vital role in providing required information for the feasibility assessment studies. The processes involved in deriving the satellite based information are explained with Ken-Betwa case study. Using this satellite derived information reservoir submergence analysis and irrigation command analysis were described for one proposed dam site namely Neemkheda. The results of the analysis provide the decision makers to arrive at selection of suitable sites among the proposed dam sites and the final reservoir levels and area that can be irrigated under its command. 相似文献
24.
Flexural response of piles under liquefied soil conditions 总被引：1，自引：1，他引：1
The paper pertains to the development of a generalized procedure to analyze and predict the flexural behavior of axially and
laterally loaded pile foundations under liquefied soil conditions. Pseudo-static analysis has been carried out taking into
consideration the combined effect of axial load and lateral load. Based on the available literature effect of degradation
on the modulus of subgrade reaction due to soil liquefaction has been incorporated in the analysis. The developed program
was calibrated and validated by comparing the predicted behavior of the pile with theoretical and experimental results reported
in literature. The predicted behavior has been found to be in excellent to very good agreement with the theoretical and observed
values in the field, respectively. The present study highlights the importance of considering the axial load from the superstructure
along with the inertia forces from the superstructure and the kinematic forces from the liquefied soil in the design of pile
foundations in liquefiable areas. The significance of densification of the soil in the liquefiable areas and presence of an
adequate top non-liquefied soil cover causing appreciable reduction in deflection and bending moment experienced by the piles
has been highlighted. 相似文献
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Mathematical Geosciences - 相似文献
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Ravi Shanker S. Nag A. Ganguly A. Absar B. P. Rawat G. S. Singh 《Journal of Earth System Science》2001,110(1):63-76
The diamond bearing pipe rocks in Majhgawan-Hinota (more than four pipes) occur as intrusives in sandstones of Kaimur Group.
These Proterozoic (974 ±30-1170 ±20 Ma) intrusive rocks, occupying the southeastern margin of Aravalli craton, were called
as ‘micaceous kimberlite’ in tune with the reported kimberlite occurrences from other parts of the world. Judging from the
definition of kimberlite, as approved by the IUGS Subcommission on Systematics of Igneous Rocks, it is not justified to call
these rocks as ‘micaceous kimberlite’. Rather the mineralogical assemblages such as absence of typomorphic mineral monticellite
(primary), abundance of phlogopite cognate, frequent presence of barite and primary carbonate mostly as calcite coupled with
ultrapotassic and volatile-rich (dominantly H2O) nature and high concentration of incompatible elements (such as Ba, Zr, Th, U), low Th/U ratios, low REE and no Eu-anomaly
clearly indicate a close similarity with that of South African orangeites. Thus orangeites of Proterozoic age occur outside
the Kaapvaal craton of South Africa which are much younger (200 Ma to 110 Ma) in age. 相似文献
28.
Performance analysis of different predictive models for crop classification across an aridic to ustic area of Indian states 总被引：1，自引：0，他引：1
The purpose of this study is to present comparative performance analysis of different machine learning algorithms for large area crop classification. Ten Indian districts with significant rabi crops viz. wheat, mustard, gram, red lentils (masoor) have been selected for the study. Most popular classical ensemble models – bagging/ARCing, random forest (RF), gradient boosting and Importance Sampled Learning Ensemble (ISLE) with traditional single model (decision tree) have been selected for comparative analysis. To incorporate dependency of large area crop in different variables viz. parent material and soil, phenology, texture, topography, soil moisture, vegetation, climate etc., 35 digital layers are prepared using different satellite data (ALOS DEM, Landsat-8, MODIS NDVI, RISAT-1, Sentinental-1A) and climatic data (precipitation, temperature). In rabi season, field survey about crop type is carried out to prepare training data. Performance is evaluated on the basis of marginal rates, F-measure and Jaccard’s coefficient of community, Classification Success Index and Agreement Coefficients. Score is calculated to rank the algorithm. RF is best performer followed by gradient boosting for crop classification. Other ensemble methods ARCing, bagging and ISLE are in decreasing order of performance. Traditional non-ensemble method decision tree scored higher than ISLE. 相似文献
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It is well-versed that transport occurrence is vital for in stream rehabilitation, river restoration and installment of sediment sampler on river beds. Current practice emulates the use of continuous pre-diction using reach-averaged approach. However, prediction of transport occurrence entails the use of binary model through the execution of logistic regression analysis. Bed load and turbulence data were physically measured at mountainous region with divergent surface bedform in its presence. The para-meterization and statistical approaches are treated in the similar fashion with multiple regression except for the test for model fit and model selection criterion. The parameters on near-bed turbulence char-acteristics at the entrainment threshold were assigned as independent variables containing 15 pre-dictors. Almost 80 models were generated by selecting the best possible combination in accordance with the statistical precaution of alleviating multicollinearity issue. It is postulated that the model containing shields stress in the form of turbulent kinetic energy (TKE) at vertical direction and fractional time for second quadrant provides better estimation of potential location for greatest sediment-entrainment;hence a high possibility for transport occurrence. 相似文献