基于参数评估方法的不同灌溉方式的适宜性及其比较——以伊朗Khosouyeh Dam子流域为例（英文）

随着人口的急剧增加,人们对粮食和农产品的需求也会增加,与之相关联的农业土地利用问题也必然会越来越多,因此有必要研究土地的最大生产潜力——达到最大的生产能力而对农地不会产生不利影响,土地适宜性评估是实现这一目标的最重要方式。本研究的主要目的是基于参数评估方法对不同灌溉方法的优缺点进行评估与比较,以伊朗南部法尔斯省Khosouyeh Subbasin为例,该区域面积约为221402 ha。首先制备了土地单位图,选择了37个样本点,评估和分析其土壤性质,并采用GIS技术生成区域滴灌和漫灌的适宜性图。结果显示,对漫灌而言,98.42%的土地被归类为永久性不适合(N_2),1.52%目前不适合(N_1);对滴灌而言,77.73%的面积被归类为永久不适合(N_2),6.05%目前不适合(N_1),12.43%略适合(S_3)和3.79%适度适合(S_2)。滴灌和漫灌的限制因素都是土壤深度和土地坡度。     

Sampling Density in Regional Exploration and Environmental Geochemical Studies: A Review

Natural Resources Research - A variety of factors contribute to the proper and efficient evaluation of geochemical programs including sampling medium, sample size and sample fraction, sampling...     

Correction to: Geochemical Prospectivity Mapping Through a Feature Extraction–Selection Classification Scheme

Natural Resources Research - The original version of this article unfortunately contained a mistake in the second part of Table 3. The data in last four rows of Table 3, i.e.,...     

An Improved Data-Driven Multiple Criteria Decision-Making Procedure for Spatial Modeling of Mineral Prospectivity: Adaption of Prediction–Area Plot and Logistic Functions

Natural Resources Research - Assigning realistic weights to targeting criteria in order to synthesize various geo-spatial datasets is one of the most important challenging tasks for mineral...     

Comparison of new individual and hybrid machine learning algorithms for modeling and mapping fire hazard: a supplementary analysis of fire hazard in different counties of Golestan Province in Iran

Natural Hazards - The forest fire hazard mapping using the accurate models in the fire-prone areas has particular importance to predict the future fire occurrence and allocate the resources for...     

Assessment of Various Fuzzy c-Mean Clustering Validation Indices for Mapping Mineral Prospectivity: Combination of Multifractal Geochemical Model and Mineralization Processes

This paper describes the application of an unsupervised clustering method, fuzzy c-means (FCM), to generate mineral prospectivity models for Cu?±?Au?±?Fe mineralization in the Feizabad District of NE Iran. Various evidence layers relevant to indicators or potential controls on mineralization, including geochemical data, geological–structural maps and remote sensing data, were used. The FCM clustering approach was employed to reduce the dimensions of nine key attribute vectors derived from different exploration criteria. Multifractal inverse distance weighting interpolation coupled with factor analysis was used to generate enhanced multi-element geochemical signatures of areas with Cu?±?Au?±?Fe mineralization. The GIS-based fuzzy membership function MSLarge was used to transform values of the different evidence layers, including geological–structural controls as well as alteration, into a [0–1] range. Four FCM-based validation indices, including Bezdek’s partition coefficient (V_Pc) and partition entropy (V_Pe) indices, the Fukuyama and Sugeno (V_FS) index and the Xie and Beni (V_XB) index, were employed to derive the optimum number of clusters and subsequently generate prospectivity maps. Normalized density indices were applied for quantitative evaluation of the classes of the FCM prospectivity maps. The quantitative evaluation of the results demonstrates that the higher favorability classes derived from V_FS and V_XB (N_d?=?9.19) appear more reliable than those derived from V_Pc and V_Pe (N_d?=?6.12) in detecting existing mineral deposits and defining new zones of potential Cu?±?Au?±?Fe mineralization in the study area.

     

Assessing and Modeling the Impacts of Wetland Land Cover Changes on Water Provision and Habitat Quality Ecosystem Services

Natural Resources Research - Understanding the spatial–temporal dynamics of wetland land cover (LC) changes and their impacts on ecosystem services (ESs) is essential for wetland conservation...     

海洋工程试验池中风场模拟

在考虑海洋工程装备在极端海况和运行海况下的载荷与受力,风载荷也是一个不可忽视的因素.目前物理模型试验仍是研究海洋工程结构物载荷与运动性能的重要手段,而深海结构物在水平漂移运动较大,如何在较大范围内得到满足试验要求的风场,是提高试验能力的重要问题.应用数值计算方法对大范围的风场模拟进行了分析,并进行了相应的物理实验,在此基础上对海洋工程试验的风场模拟提出了若干建议.     

A numerical modeling of hydrodynamic characteristics of various planing hull forms

A numerical algorithm based on the boundary element method (BEM) is presented for predicting the hydrodynamic characteristics of the various planing hull forms. The boundary integral equation is derived using Green's theorem on the wetted body surface and the free surface. The ventilation function at the transom is estimated with Doctor's empirical formula. This function is defined as the transom zone free surface boundary condition. The combined boundary integral equation and modified free surface boundary condition are simultaneously solved to determine the dipole on the wetted hull surface and the source on the free surface. The method is applied to investigate three examples of planing hulls, which include flat-plates, as well as wedge-shaped and variable deadrise planing hulls. Their hydrodynamic characteristics are calculated for different speeds. Computational results are presented and compared with existing theories and experiments. On the whole, the agreement between the present method and the selected experimental and numerical data is satisfactory.     

Convergence-control approach for rock tunnels reinforced by grouted bolts,using the homogenization concept

The scope of this paper is to introduce a method for the analysis of rock tunnels reinforced by grouted bolts, based on the convergence-control approach. The analytical formulations presented in this paper refers to an elasto-plastic behavior of the rock mass and the latest Hoek and Brown yield criterion (Version 2002). In order to model the reinforced plastic zone, the equivalent material approach was taken into account such that the apparent strength of the rock mass is improved as a consequence of the bolting effect. The general design guides and examples presented are intended to facilitate the comprehension and application of the proposed analytical solution in practice.