Geostatistical features of streambed vertical hydraulic conductivities in Frenchman Creek Watershed in Western Nebraska     

Olufemi P. Abimbola  Aaron R. Mittelstet  Troy E. Gilmore 《水文研究》2020,34(16):3481-3491

This study evaluated the spatial variability of streambed vertical hydraulic conductivity (K_v) in different stream morphologies in the Frenchman Creek Watershed, Western Nebraska, using different variogram models. Streambed K_v values were determined in situ using permeameter tests at 10 sites in Frenchman, Stinking Water and Spring Creeks during the dry season at baseflow conditions. Measurements were taken both in straight and meandering stream channels during a 5 day period at similar flow conditions. Each test site comprised of at least three transects and each transect comprised of at least three K_v measurements. Linear, Gaussian, exponential and spherical variogram models were used with Kriging gridding method for the 10 sites. As a goodness-of-fit statistic for the variogram models, cross-validation results showed differences in the median absolute deviation and the standard deviation of the cross-validation residuals. Results show that using the geometric means of the 10 sites for gridding performs better than using either all the K_v values from the 93 permeameter tests or 10 K_v values from the middle transects and centre permeameters. Incorporating both the spatial variability and the uncertainty involved in the measurement at a reach segment can yield more accurate grid results that can be useful in calibrating K_v at watershed or sub-watershed scales in distributed hydrological models.  相似文献   

Micromechanical approach to effective viscoelastic properties of micro‐fractured geomaterials          下载免费PDF全文

Cássio B. Aguiar  Samir Maghous 《国际地质力学数值与分析法杂志》2018,42(16):2018-2046

The aim of this paper is to formulate a micromechanics‐based approach to non‐aging viscoelastic behavior of materials with randomly distributed micro‐fractures. Unlike cracks, fractures are discontinuities that are able to transfer stresses and can therefore be regarded from a mechanical viewpoint as interfaces endowed with a specific behavior under normal and shear loading. Making use of the elastic‐viscoelastic correspondence principle together with a Mori‐Tanka homogenization scheme, the effective viscoelastic behavior is assessed from properties of the material constituents and damage parameters related to density and size of fractures. It is notably shown that the homogenized behavior thus formulated can be described in most cases by means of a generalized Maxwell rheological model. For practical implementation in structural analyses, an approximate model for the isotropic homogenized fractured medium is formulated within the class of Burger models. Although the approximation is basically developed for short‐term and long‐term behaviors, numerical applications indicate that the approximate Burger model accurately reproduce the homogenized viscoelastic behavior also in the transient conditions.  相似文献   

不同类型的高位虾池排污对秋茄幼苗生长的影响     

田园  陈光程  唐飞龙  郑春芳  叶勇 《海洋学报(英文版)》2018,37(6):112-120

中国多数红树林陆地边缘存在着大量的养虾池塘。这些养虾池塘可通过：（1）换塘外排废水，（2）清塘直排污泥影响周围的红树林。本研究共包含两个实验，来探讨这两种类型的排污对秋茄幼苗生长的影响。实验一模拟虾池常规换塘情况，研究换塘废水对秋茄幼苗生长的影响。实验二设置四种虾池清塘污泥沉积厚度（0 cm，2 cm，4 cm，8 cm），研究虾池清塘污泥的累积效应对秋茄幼苗生长的影响。结果如下：在5，15和25三种盐度下，虾池换塘废水未对秋茄生长指标造成显著影响；而清塘污泥对秋茄生长的影响与其沉积厚度有关，大多数生长参数在污泥沉积厚度为4 cm时呈现最大值。秋茄幼苗在适量的沉积厚度下加速了生长，且本实验秋茄幼苗对虾池清塘污泥的耐受性为沉积厚度8 cm。  相似文献   

RETRACTED ARTICLE: Horizontal global solar radiation estimation using hybrid SVM-firefly and SVM-wavelet algorithms: a case study     

Mohammadi  Kasra  Shamshirband  Shahaboddin  Danesh  Amir Seyed  Zamani  Mazdak  Sudheer  Ch. 《Natural Hazards》2020,102(3):1613-1614

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Algorithm for the Atmospheric Correction of Shortwave Channels of the MSU-MR Radiometer of the Meteor-M No. 2 Satellite     

Kuchma  M. O.  Bloshchinskiy  V. D. 《Izvestiya Atmospheric and Oceanic Physics》2020,56(9):909-915

Izvestiya, Atmospheric and Oceanic Physics - The problem of atmospheric correction for shortwave channels of a multispectral low-resolution scanning radiometer onboard the Meteor-M No. 2 satellite...  相似文献   

Traces of Seismic Activity in Architectural Monuments in Derbent,Dagestan     

Korzhenkov  A. M.  Gadzhiev  M. S.  Ovsyuchenko  A. N.  Lar’kov  A. S.  Rogozhin  E. A. 《Izvestiya Atmospheric and Oceanic Physics》2020,56(7):633-656

Izvestiya, Atmospheric and Oceanic Physics - As a result of studies conducted in the city of Derbent, it is established that its monumental fortification structures erected at the end of the 560s...  相似文献   

Estimating Model Parameters from Self-Potential Anomaly of 2D Inclined Sheet Using Whale Optimization Algorithm: Applications to Mineral Exploration and Tracing Shear Zones     

Gobashy  Mohamed  Abdelazeem  Maha  Abdrabou  Mohamed  Khalil  Mohamed H. 《Natural Resources Research》2020,29(1):499-519

The use of spontaneous potential (SP) anomalies is well known in the geophysical literatures because of its effectiveness and significance in solving many complex problems in mineral exploration. The inverse problem of self-potential data interpretation is generally ill-posed and nonlinear. Methods based on derivative analysis usually fail to reach the optimal solution (global minimum) and trapped in a local minimum. A new simple heuristic solution to SP anomalies due to 2D inclined sheet of infinite horizontal length is investigated in this study to solve these problems. This method is based on utilizing whale optimization algorithm (WOA) as an effective heuristic solution to the inverse problem of self-potential field due to a 2D inclined sheet. In this context, the WOA was applied first to synthetic example, where the effect of the random noise was examined and the method revealed good results using proper MATLAB code. The technique was then applied on several real field profiles from different localities aiming to determine the parameters of mineralized zones or the associated shear zones. The inversion parameters revealed that WOA detected accurately the unknown parameters and showed a good validation when compared with the published inversion methods.

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空间分析与生物地球化学循环:西藏林周县大骨节病患病村与非患病村的比较研究     

田原  查欣洁  高星  戴尔阜  余成群 《资源与生态学报(英文版)》2020,11(2):232-246

西藏林周县是我国大骨节病(KBD)患病较为严重的地区之一,本文将林周县作为研究区,通过使用地理探测器(GeoDetector)量化分析KBD患病率风险因子的影响,并使用环境化学方法验证空间分析结果。通过对10个潜在影响因子的分析以及对当地KBD患病村和非患病村的土壤-水-粮食-人这一生物地球化学循环的环境化学分析,结果表明:(1)林周县KBD由一组多重且交互作用的环境影响因子共同作用影响,其中最重要的控制因子是地层因子;(2)所有环境介质(土壤、水、谷物)及人体组织中的硒元素浓度在KBD患病区均低于非患病区;(3)当地居民对硒和铬的摄入严重不足,尤其是KBD患病村中居民硒元素平均日摄入量(ADD)大约仅为世界卫生组织(WHO)建议的成人基本摄入量下限的4%;(4)我们推测,当地居民患病主要是由于地层这一影响因子,这是由于通过生态系统的迁移转化导致当地人口严重硒缺乏,最终导致地方性生物地球化学硒缺乏。  相似文献   

Evaluation of Interactions Between Oilfield Chemicals and Reservoir Rocks     

Wuyep  E. O.  Oluyemi  G. F.  Yates  K.  Akisanya  A. R. 《Natural Resources Research》2020,29(2):1239-1258

Natural Resources Research - Sand failure and production occurs when the formation stress exceeds the strength of the formation, which is derived majorly from the natural material that cements the...  相似文献   

Appraisal of Hydraulic Flow Units and Factors of the Dynamics and Contamination of Hydrogeological Units in the Littoral Zones: A Case Study of Akwa Ibom State University and Its Environs,Mkpat Enin L.G.A,Nigeria     

George  Nyakno J. 《Natural Resources Research》2020,29(6):3771-3788

Natural Resources Research - Borehole-controlled one-dimensional geo-electric data were integrated with water samples obtained from boreholes drilled near the vertical electrical sounding at 12...  相似文献