Uncertainties in DRAINMOD predictions of subsurface drain flow for an Indiana silt loam using the GLUE methodology

Good modelling practice requires the incorporation of uncertainty analysis into hydrologic/water quality models. The generalized likelihood uncertainty estimation procedure was used to evaluate the uncertainty in DRAINMOD predictions of daily, monthly, and yearly subsurface drain flow. A variance‐based sensitivity analysis technique, the extended Fourier amplitude sensitivity test, was used to identify the main sources of prediction uncertainty. The analysis was conducted for the experimental drainage field at the Southeast Purdue Agricultural Center in Indiana. Six years of data were used and the uncertainties in eight model parameters were considered to analyse how uncertainties in input parameters propagate to model outputs. The width of 90% confidence interval bands of drain flow ranged from 0 to 0·6 cm day^?1 for daily predictions, from 0 to 3·1 cm month^?1 for the monthly predictions, and from 7·6 to 12·4 cm year^?1 for yearly predictions. Annual drain flow predicted by DRAINMOD fell well within the 90% confidence bounds. Model results were most sensitive to the vertical saturated hydraulic conductivity of the restrictive layer and the lateral hydraulic conductivity of the deepest soil layer, followed by the lateral hydraulic conductivity of the top soil layer and surface micro‐storage. Parameter interactions also contributed to the prediction uncertainty. Copyright © 2006 John Wiley & Sons, Ltd.     

A study on hydrological series of the Niger River

Abstract

The Hubert segmentation procedure has been applied to historical series of annual average discharges of the Niger River at Koulikoro (Mali), Niamey (Niger) and Lokoja (Nigeria) stations. The breaks, especially those identified at Koulikoro and Niamey, match well with those identified in the Senegal River series at Bakel using the same procedure. Lokoja departs from this regional pattern, as it shows in the late 1980s a return to wetter conditions much earlier than the other three stations. The magnitudes of the variation of the inter-annual means between the alternating wet and dry periods are significant and similar. These results seem to suggest that phenomena causing non-stationarity in hydrological series can have a sub-continental impact or, in contrast, may be more limited in their spatial coverage.

Editor Z.W. Kundzewicz; Associate editor H. Aksoy

Citation Abrate, T., Hubert, P., and Sighomnou, D., 2013. A study on hydrological series of the Niger River. Hydrological Sciences Journal, 58 (2), 271–279.     

TLP干式钻完井技术特点分析

TLP使得干式井口在深水的应用成为可能,与常规的深水开发模式水下井口相比,TLP降低了钻完井作业的难度和费用,尤其在后期修井和调整并作业时,能够大大降低项目的投资,经济效益明显.TLP目前在墨西哥湾、北海及印度尼西亚深水油气田均有采用.目前针对TLP的钻完井设计和作业程序国内开展研究较少,制约了深水油气田开发前期方案设计工作的开展.因此,重点介绍了TLP对钻完井程序的影响;对于不同的平台钻机配置,总结了TLP的钻完井程序;提出了钻完井设计和作业过程中,TLP对回接套管、升沉补偿等问题的要求,分析了与常规深水湿式井口的温度剖面差异,为开展TLP钻完井技术研究和前期方案设计提供参考.     

以工序分析为基础的地质勘查工程监理理论探讨

建立了以工序分析为基础的地质资源勘查工程项目监理理论,即对工序活动条件和工序活动效果的质量控制.运用该理论选择盐井钻探工程为典型案例,初步分析推演了地质资源勘查钻探工程施工与监理过程中的一些基础理论问题,包括质量验收单元的划分方法与依据、质量验收的内容与监理资料的构成、监理方的质量控制手段、质量控制程序实施细则等核心内容及存在的问题,从而实现与其他行业实体工程的监理工作方法的统一.     

Trace element study in Tisa River and Danube alluvial sediment in Serbia

The contaminated sediment serves as a long-term source of toxic elements,since that mobility and transport in the environment of these elements are strongly influenced to associated solid phase.In this study,the modified Tessier sequential extraction procedure was applied for the fractionation of Cd,As,Hg,Cu,Zn,Cr,Pb,Ni and V in the sediments（Tisa River and canal sediments - Danube alluvial formation）,to obtain an overall classification of trace element pollution in these areas through its spatial distribution.Investigations of this region are important due to the widespread occurrence of metal mining activities throughout the Tisa and Danube drainage basins and possibilities of contamination with toxic elements at studies localities.Five steps of the sequential extraction procedure partitioned elements into CH₃COONH₄ extractable（F1）,NH₂OH·HC carbonate extractable and easily reducible（F₂）, H₂C₂O₄/（NH₄）₂C₂O₄ moderately reducible（F3）,H₂O₂-HNO₃ organic extractable（F4）,and HCl acid soluble residue （F5）.Analyses of the extracts were performed by flame atomic absorption spectrometry.To indicate the degree of risk of toxic elements,risk assessment code and contamination factor have been used.The results of partitioning study indicate that more easily mobilized forms（metals in adsorbed/exchangeable/carbonate forms or bound to amorphous Fe and Mn oxyhydroxides and Fe and Mn oxides） were predominant for copper,zinc,cadmium and lead,which can be used as indicators for input from anthropogenic source.In contrast,the largest amount of chromium and nickel were associated with the inert fraction,which reduced their solubility and rendered them immobile under natural conditions and indicative of natural origins.Most of remaining portion of metals was bound to ferromanganese oxides fraction.It is concluded that sequential extraction results proved useful to distinguish between anthropogenic and geochemical sources of elements in the sediments.     

Estimating bearing response in symmetric and asymmetric‐plan isolated buildings with rocking and torsion

A comprehensive approach is developed to estimate relevant design quantities—lateral deformations and axial forces—in isolation systems composed of lead–rubber bearings. The approach, applicable to symmetric and asymmetric‐plan systems, includes the effects of bidirectional excitation, rocking, and torsion; and is the culmination of previous work on this topic. The approach is based on nonlinear response history analysis of an isolated block using an advanced bearing model that incorporates the interaction between axial force and lateral response of the bearing, known as axial‐load effects. The rocking response of the system and peak axial forces are shown to depend on the isolation period, the normalized strength—or yield strength normalized by peak ground velocity, the ratios of rocking frequency about each horizontal axis to vertical frequency, and the normalized stiffness eccentricity. In an attempt to develop results widely applicable to asymmetric‐plan systems, eccentricity is introduced by varying the stiffnesses and strengths of individual bearings in an idealized, rectangular plan. This idealized system approach is shown to have limited success; when applied to actual asymmetric‐plan systems the design equations to estimate response are accurate for lateral deformations but err by up to 25% for axial forces. Copyright © 2006 John Wiley & Sons, Ltd.     

大比例尺航测数字化测图内转外作业中的精度控制

通过对某城区1：500航测数字化测图中，全数字摄影测量工作站上采集的数据按地形要素分类进行平面精度分析，找出不同要素的精度规律和影响精度的原因，在外业调绘修补测时采取针对性措施，保证最终成图的精度质量。     

Evaluation of modal pushover analysis using generic frames

An Erratum has been published for this article in Earthquake Engineering and Structural Dynamics 2003; 32:1795. The recently developed modal pushover analysis (MPA) has been shown to be a significant improvement over the pushover analysis procedures currently used in structural engineering practice. None of the current invariant force distributions accounts for the contribution of higher modes—higher than the fundamental mode—to the response or for redistribution of inertial forces because of structural yielding. By including the contributions of a sufficient number of modes of vibration (generally two to three), the height‐wise distribution of responses estimated by MPA is generally similar to the ‘exact’ results from non‐linear response history analysis (RHA). Although the results of the previous research were extremely promising, only a few buildings were evaluated. The results presented below evaluate the accuracy of MPA for a wide range of buildings and ground motion ensembles. The selected structures are idealized frames of six different heights: 3, 6, 9, 12, 15, and 18 stories and five strength levels corresponding to SDF‐system ductility factor of 1, 1.5, 2, 4, and 6; each frame is analysed for 20 ground motions. Comparing the median values of storey‐drift demands determined by MPA to those obtained from non‐linear RHA shows that the MPA predicts reasonably well the changing height‐wise variation of demand with building height and SDF‐system ductility factor. Median and dispersion values of the ratios of storey‐drift demands determined by MPA and non‐linear‐RHA procedures were computed to measure the bias and dispersion of MPA estimates with the following results: (1) the bias and dispersion in the MPA procedure tend to increase for longer‐period frames and larger SDF‐system ductility factors (although these trends are not perfect); (2) the bias and dispersion in MPA estimates of seismic demands for inelastic frames are usually larger than for elastic systems; (3) the well‐known response spectrum analysis (RSA), which is equivalent to the MPA for elastic systems, consistently underestimates the response of elastic structures, e.g. up to 18% in the upper‐storey drifts of 18‐storey frames. Finally, the MPA procedure is simplified to facilitate its implementation in engineering practice—where the earthquake hazard is usually defined in terms of a median (or some other percentile) design spectrum for elastic systems—and the accuracy of this simplified procedure is documented. Copyright © 2003 John Wiley & Sons, Ltd.     

滑坡预报的多元回归分析方法

在回顾了滑坡预报的概念、类型及已有滑坡预报的几种主要模型的基础上，利用多元回归分析方法，根据最小二乘法原理，建立了非线性回归预报模型，提出滑坡破坏的时间为位移．时间曲线的拐点，此方法一般适合于临滑预报。结合实例，利用黄龙西村滑坡位移．时间监测资料，采用该模型进行滑坡时间预报，和其他滑坡预报模型预报的结果接近，说明该模型具有一定的合理性。