Modelling suspended sediment concentration using artificial neural networks for Gangotri glacier

The dynamics of suspended sediment involves inherent non‐linearity and complexity because of existence of both spatial variability of the basin characteristics and temporal climatic patterns. This complexity, therefore, leads to inaccurate prediction by the conventional sediment rating curve (SRC) and other empirical methods. Over past few decades, artificial neural networks (ANNs) have emerged as one of the advanced modelling techniques capable of addressing inherent non‐linearity in the hydrological processes. In the present study, feed‐forward back propagation (FFBP) algorithm of ANNs is used to model stage–discharge–suspended sediment relationship for ablation season (May–September) for melt runoff released from Gangotri glacier, one of the largest glaciers in Himalaya. The simulations have been carried out on primary data of suspended sediment concentration (SSC) discharge and stage for ablation season of 11‐year period (1999–2009). Combinations of different input vectors (viz. stage, discharge and SSC) for present and previous days are considered for development of the ANN models and examining the effects of input vectors. Further, based on model performance indices for training and testing phase, a suitable modelling approach with appropriate model input structure is suggested. The conventional SRC method is also used for modelling discharge–sediment relationship and performance of developed models is evaluated by statistical indices, namely; root mean square error (RMSE), mean absolute error (MAE) and coefficient of determination (R²). Statistically, the performance of ANN‐based models is found to be superior as compared to SRC method in terms of the selected performance indices in simulating the daily SSC. The study reveals suitability of ANN approach for simulation and estimation of daily SSC in glacier melt runoff and, therefore, opens new avenues of research for application of hybrid soft computing models in glacier hydrology. Copyright © 2015 John Wiley & Sons, Ltd.     

Load-displacement and upper-bound solutions of a loaded laterally pile in clay based on a total-displacement-loading EMSD method

A total-displacement-loading approach based on the extended mobilisable strength design (EMSD) method is developed for predicting nonlinear foundation responses and upper-bound capacities with continuous velocity fields. Different from EMSD, the new approach turns optimizing a minimum energy solution into solving an elastic problem with strain-dependent equivalent elastic modulus. The strain-dependent modulus is determined by a nonlinear iterative method. This transform guarantees that the reaction force is consistent with the elastic solution in early stages of loading and gradually approaches an upper-bound solution at a large value of displacement. The approach is demonstrated on a problem of the laterally loaded pile.     

PATTERNS OF HORSE DEVOLUTION AND TRACTOR DIFFUSION IN ILLINOIS, 1920–1982*

The concern is to extend certain diffusion concepts to devolution. In this example, tractors replaced horses because tractors had advantages over horses. Logistic curves depict well the temporal rate of tractor acceptance and of horse abandonment. Although differing somewhat in time, the spatial patterns of adoption and abandonment are similar. They centered early in east central Illinois, a prosperous agricultural core, and spread outward. Laggard counties as well as persister ones were mainly in southern Illinois, a peripheral area with a relatively impoverished agriculture. Influences on the patterns include farm value, size, and type and land quality.     

判定光变周期的一种方法

Jurkevich方法通常用来发现光变曲线的周期 ,并且根据V2 m 极小值的大小来验证所发现的光变周期可靠性。但是 ,这种验证方法又带有一定的不确定性 ,最佳的方法是把所发现的周期与观测光变曲线拟合 ,得出每一个周期的振幅 ,以振幅大小来验证所发现的光变周期的可靠性。将此方法用于OJ2 87的历史光变曲线 ,得到其最主要的周期为 11.9年 ,与其它结果相符合。     

The fractal shape of sutured quartz grain boundaries: application as a geothermometer

Along grain boundaries of quartz from metamorphic and igneous rocks complex interfingering (sutures) may occur. Under the light microscope the lengths of the sutures range from approximately 10–1000 m. The sutured grain boundaries are statistically self-similar over one to two orders of magnitude. They represent fractals. Their mathematical counterpart are Koch curves which are developed after two to four iterations. The fractal (Hausdorff-Besicovitch) dimensions D of sutured quartz grain boundaries from different grades of metamorphism are between ca. 1.05 and 1.30. The D-value decreases with increasing temperature during formation of the sutures. On a statistical basis, D can be used as a measure of this temperature and, therefore, as a deformation-related thermometer.     

Seismic history and consistent seismicity: Evidence from southern Italy

In this paper a method is proposed to evaluate the seismicity level of an area in a given historical period, based on records of seismic events, source characteristics and intensity attenuation with distance. Also considered is the seismic activity recorded in southern Italy during the 10th and 11th centuries, seismic records being obtained from all available sources. To determine the level of seismicity, a key role is played by source characteristics, i.e. recording modalities and activity periods of recording centers. In addition, models of intensity attenuation with distance allow the assessment of the size of the area under investigation. This paper identifies the areas, in the 10th and 11th centuries, where major earthquakes (M 6.5) did not occur during periods of silence of sources, as well as those where such events cannot be excluded. For each area, different levels of probability were determined by applying the Cox linear logistic model to historical seismic data. The completeness analysis, in terms of area and time-span coverage, is a valuable tool to assess seismicity in seismogenetic areas. The reproducibility of the model for lower magnitude earthquakes (M < 6.5) is reliable.     

1976年9月23日巴音木仁Ms 6.2级地震序列分析

本文对１９７６年巴音木仁Ｍｓ６２级地震序列进行了分析,剖析其前震序列的测震学指标异常及余震序列特征,判定了序列类型,得出一些有预报意义的结果。     

双环软钢耗能器的试验研究

本文提出了“利用两个或多个耗能元件协同工作,同时耗能来设计新型耗能器”的思想,研究设计了双环软钢耗能器,并对三种不同构造的双环软钢耗能器进行了循环加载试验,考察了耗能器的工作特性和耗能性能,揭示了耗能的机理,给出了耗能器的恢复力模型。研究结果表明,双环软钢耗参器是一种初始刚度和屈服力高、变形性能好、耗能能力强、工作性能稳定、构造简单、制作与安装方便的新型耗能减震装置,具有广阔的应用前景。     

分维扩展的数值试验研究

由于仅用一个分维值难以区分不同的形态,首先需要对原分维概念予以扩充,即把原来仅局限于无标度区内的呈直线形分布的常数分维扩充为包括无标度区上下界以外区域在内的,呈反Ｓ形分布的变量（函数）分维,使分维方法的应用不受观测尺度的限制;其次,要研究表达扩充分维的数学模型。文中论述了反Ｓ形扩充分维的数值实现方法和增强描述复杂现象的能力。     

用时面深概化法估算清江中上游流域可能最大暴雨

在分析清江流域暴雨洪水特点及含清江流域暴雨一致区内暴雨特性的基础上,推测出形成清江中上游可能最大暴雨的天气形势和梅雨形势类似,暴雨为梅雨雨带中的暴雨,水汽入流方向为西南方向,采用时面深概化法估算了清江中上游流域２４ｈ和３ｄ可能最大暴雨。