Water vapour transport of the pre-monsoon period and the general performance of the Indian summer monsoon

The advective monthly mean transfer of water vapour in the layer below 700 mbar is investigated for India for the years 1962 to 1972 and for the months January to September. The average zonal and meridional components of the transfer of water vapour for India are obtained. They are further averaged for different combinations of the pre-monsoon months from January to May and are correlated with the summer monsoon rainfall. The correlation coefficients for zonal transfer of water vapour are either negative or small positive for different combinations of the months mentioned above. The correlation coefficients for the meridional transfer of water vapour are positive. The maximum value is 0.74 for the March to May combination and is statistically significant at the 1% level.An extensive investigation is, therefore, made for the March to May averages of water vapour transfer for four broad regions of India. The parameters of water vapour transfer for these regions are compared with the threshold values and the prediction category, normal or drought, for the subsequent summer monsoon season is determined for all years. The correlation coefficient between the index of drought, as determined from parameters of water vapour transport and rainfall departure, is statistically significant at the 2% level.     

中小震近场地震动估计中地震动衰减关系的适用性分析

核工程场地设计基准地震动确定中涉及弥散地震的地震动估计，这导致中小震近场地震动估计成为被关注的研究课题。本文基于一些中小震近场地震动记录资料，分析和探讨了国内外多种地震动衰减关系对中小震近场地震动估计的适用性问题，并结合我国几个核工程地震问题研究工作的实践对中小震近场地震动衰减关系确定的思路和原则提出了建议。     

Determination of GMPE functional form for an active region with limited strong motion data: application to the Himalayan region

Advancement in the seismic networks results in formulation of different functional forms for developing any new ground motion prediction equation (GMPE) for a region. Till date, various guidelines and tools are available for selecting a suitable GMPE for any seismic study area. However, these methods are efficient in quantifying the GMPE but not for determining a proper functional form and capturing the epistemic uncertainty associated with selection of GMPE. In this study, the compatibility of the recent available functional forms for the active region is tested for distance and magnitude scaling. Analysis is carried out by determining the residuals using the recorded and the predicted spectral acceleration values at different periods. Mixed effect regressions are performed on the calculated residuals for determining the intra- and interevent residuals. Additionally, spatial correlation is used in mixed effect regression by changing its likelihood function. Distance scaling and magnitude scaling are respectively examined by studying the trends of intraevent residuals with distance and the trend of the event term with magnitude. Further, these trends are statistically studied for a respective functional form of a ground motion. Additionally, genetic algorithm and Monte Carlo method are used respectively for calculating the hinge point and standard error for magnitude and distance scaling for a newly determined functional form. The whole procedure is applied and tested for the available strong motion data for the Himalayan region. The functional form used for testing are five Himalayan GMPEs, five GMPEs developed under NGA-West 2 project, two from Pan-European, and one from Japan region. It is observed that bilinear functional form with magnitude and distance hinged at 6.5 M _w and 300 km respectively is suitable for the Himalayan region. Finally, a new regression coefficient for peak ground acceleration for a suitable functional form that governs the attenuation characteristic of the Himalayan region is derived.     

Estimation of the Probability of Exceedance of Contaminant Concentrations

Several alternative probability distributions for estimating the probability of exceedance of contaminant concentrations are examined for their appropriateness for developing inputs to risk assessments. The rationale is provided for using the log Pearson Type III distribution, a three-parameter model, for estimation of the exceedance probabilities.     

Changes in the scope for growth of blood cockles (Anadara granosa) exposed to industrial discharge

Blood cockles (Anadara granosa) were placed in plastic cages and deployed at eight locations along a pollution gradient. A control site was chosen a few kilometres away. At 2-week intervals for 8 weeks, the scope for growth of the cockles was determined. A total of 11 environmental parameters were measured during each sampling exercise for correlation with the growth index. Values of scope for growth for all the eight stations, except for stations 7 and 8, were significantly lower than the value for the control site; station 1 (nearest the discharge point) had the lowest value. Strong correlations were found between the scope for growth of the cockles and seven of the environmental parameters. The pattern of the impact of the discharge on the scope for growth of the cockles suggests that longshore currents may play a dominant role in the distribution of the industrial wastes.     

Optimal design of supplemental viscous dampers for irregular shear‐frames in the presence of yielding

A methodology for the optimal design of supplemental viscous dampers for regular as well as irregular yielding shear‐frames is presented. It addresses the problem of minimizing the added damping subject to a constraint on an energy‐based global damage index (GDI) for an ensemble of realistic ground motion records. The applicability of the methodology for irregular structures is achieved by choosing an appropriate GDI. For a particular choice of the parameters comprising the GDI, a design for the elastic behavior of the frame or equal damage for all stories is achieved. The use of a gradient‐based optimization algorithm for the solution of the optimization problem is enabled by first deriving an expression for the gradient of the constraint. The optimization process is started for one ‘active’ ground motion record which is efficiently selected from the given ensemble. If the resulting optimal design fails to satisfy the constraints for other records from the original ensemble, additional ground motions (loading conditions) are added one by one to the ‘active’ set until the optimum is reached. Two examples for the optimal designs of supplemental dampers are given: a 2‐story shear frame with varying strength distribution and a 10‐story shear frame. The 2‐story shear frame is designed for one given ground motion whereas the 10‐story frame is designed for an ensemble of twenty ground motions. Copyright © 2005 John Wiley & Sons, Ltd.     

CALCULATING THE DYNAMIC STIFFNESS MATRIX OF 2-D FOUNDATIONS BY DISCRETE WAVE NUMBER INDIRECT BOUNDARY ELEMENT METHODS

Apart from some special cases, calculating the dynamic stiffness matrix of foundations on a layered half-space, especially for embedded foundations, is computationally expensive. An efficient method for two-dimensional foundations in a horizontally layered soil media is presented in this paper. This method is based on indirect boundary element methods and uses discrete wave number solution methods for calculating Green's functions for displacements and analytical methods for the integrations over the boundary. For surface foundations, the present method applies at all frequencies. For embedded foundations or for constructing energy transmitting boundaries, because the free-field part is modelled by boundary elements and the excavated part is modelled by finite elements, the present method applies only at low frequencies for the spring coefficients (the real parts of the dynamic stiffness matrix) but applies at all frequencies for the damping coefficients (the imaginary part of the dynamic stiffness matrix) for undamped sites. The novelty of the method can be used for three-dimensional foundations. © 1997 by John Wiley & Sons, Ltd.     

从抗震设防类别探讨室内地震应急避难场所的选择

区分建筑物的抗震设防类别是进行抗震设计的前提和依据。本文针对当前我国室内地震应急避难场所认定面临的现有建筑的抗震安全性问题,根据不同版本的《建筑工程抗震设防分类标准》和《建筑抗震设计规范》,对现有体育、会展、教育建筑等设计、施工时依据的抗震设防类别、标准、规范进行分析研究,以为室内地震应急避难场所的选择提供参考,从而推动室内地震应急避难场所的认定工作。     

Adaptation of heat and mass exchange model to the calculation of diurnal water temperature regime in a stratified reservoir

A box model algorithm for heat and mass exchange model for a valley reservoir was adapted for the diurnal calculation of hydrological characteristics. Field observation data were used to obtain an empirical dependence for the calculation of the rate of vertical water mixing of water in a water body. The verification of the new model demonstrated a good quality of calculation for short-term prediction of water temperature. Recommendations are given for the further improvement of the calculation algorithm.     

On the estimation of accuracy for global models of gravitational field of the earth

The methods and techniques for estimating the accuracy of global models of the Earth’s gravity field in the form of spherical harmonic expansion of the geopotential are analyzed. Various methods for obtaining the a priori and a posteriori estimates for the accuracy are considered and classified. The application of different approaches is illustrated by numerical examples for nine models, including those recently developed using the modern methods of space geodesy. The basic requirements for the database and software for estimating the accuracy are formulated.     

Unified fractional differential approach for transient interporosity flow in naturally fractured media

A unified approach to modeling flows of slightly compressible fluids through naturally fractured media is presented. The unified fractional differential model is derived by combining the flow at micro scale for matrix blocks and macro scale for fractures, using the transient interporosity flow behavior at the interface between matrix blocks and fractures. The derived model is able to unify existing transient interporosity flow models formulated for different shapes of matrix blocks in any medium dimensions. The model is formulated in the form of a fractional order partial differential equation that involves Caputo derivative of order 1/2 with respect to time. Explicit solutions for the unified model are derived for different axisymmetrical spatial domains using Hankel or Hankel–Weber finite or infinite transforms. Comparisons between the predictions of the unified model and those obtained from existing transient interporosity flow models for matrix blocks in the form of slabs, spheres and cylinders are presented. It is shown that the unified fractional derivative model leads to solutions that are very close to those of transient interporosity flow models for fracture-dominant and transitional fracture-to-matrix dominant flow regimes. An analysis of the results of the unified model reveals that the pressure varies linearly with the logarithm of time for different flow regimes, with half slope for the transitional fracture-to-matrix dominant flow regime vs. the fracture and matrix dominant flow regimes. In addition, a new re-scaling that involves the characteristic length in the form of matrix block volume to surface area ratio is derived for the transient interporosity flow models for matrix blocks of different shapes. It is shown that the re-scaled transient interporosity flow models are governed by two dimensionless parameters Θ and Λ compared to only one dimensionless parameter Θ for the unified model. It is shown that the solutions of the transient interporosity flow models for different shapes of matrix blocks are almost identical for the re-scaled variables. Furthermore, the driving parameters for solution behavior are identified based on asymptotic approximations for different flow regimes. It is found that the matrix diffusion and the matrix area-to-volume ratio affect the solution behavior only for the transitional fracture-to-matrix dominant flow regime, that the capacitance ratio affects the solution behavior only for transitional and matrix dominant flow regimes and that the fracture diffusion is involved in all three flow regimes. Similar identification of the driving parameters is also presented in the re-scaled case.     

Development of marine water quality criteria for the USA

The US Environmental Protection Agency has developed guidelines for deriving numerical national water quality criteria for the protection of aquatic organisms and their uses. These guidelines provide the method for deriving water quality criteria, including minimum data base requirements, data evaluation procedures, and calculations. The guidelines have been in place for a long time, and states have used them to derive water quality standards for their water bodies. More recent efforts have been directed towards the development of technical guidance based on the concept that bioassessment and biocriteria programs for estuaries and near coastal waters are interrelated and are critical components of comprehensive water resource protection and management. This is a holistic approach to protection and management, integrating biological assessments into traditional chemical and physical evaluations and augmenting the established water quality criteria. The method for deriving water quality criteria and the approach for biocriteria development for marine systems are described.     

The forecasting of streamflow using the method of characteristic modes

The method of characteristic modes proposed by Farmer for nonstationary processes is tested for the forecasting of streamflow. The calculation of the auto-correlation matrix is modified for processes which generate a single record and an algorithm is proposed for the optimum choice of the number of past data and mode vectors. Results for 12 gauging stations in various parts of the world are presented.     

A procedure for estimation of the upper bound for earthquake magnitudes

A procedure is described for estimation of the maximum feasible magnitude for earthquakes in a given region. This procedure provides a confidence interval for the upper bound without the need for any numerical calculation.     

桥梁抗震设计规范的现状与发展趋势

本文对世界主要桥梁结构抗震设计规范的现状进行了较为详细的对比,指出我国现行《公路工程抗震设计规范》中存在的一些缺点。本文还对目前国际上桥梁结构抗震设计规范的发展动向进行了总结,提出了修订我国新《城市桥梁抗震设计规范》的一些意见。     

Engineering-geological substantiation of water resource protection in the zones of oil and gas fields

The hydrochemical background and the specific features of pollution of geological environmental components by hydrocarbons and chemical components in the industrial sites of oil and gas fields is characterized for two types of natural-anthropogenic environments with different hydrogeological conditions. A methodology is proposed for comprehensive environmental-hydrogeological studies for the development of information support for the assessment of the hazard and risk for the environmental conditions, organization of complex environmental monitoring, and projecting of measures for protection of water resources.     

Electromagnetic response function for the semi-annual variations estimated by the single-station method using the night-time values of the geomagnetic fields

The geomagnetic night-time values were used to estimate the electromagnetic response function Q1 for half-year period. If the spatial structure of the source field can be described by the approximation, one can estimate the Q1 value using the single-station Z/H method. This technique enables us to carry out regional deep geomagnetic sounding by the method. The data used for analyses are geomagnetic night-time values for about, typically, 26 years from 5 good-quality stations and for several years from 34 stations distributed over the globe. The results indicate that the night-time values yield more reliable response estimates for half-year period compared to the usual estimates obtained from daily means. It implies that the approximation for the night-time fields holds good for the half-year period, but the daily means are not suitable for estimating the response function of the semi-annual variations by using the single-station method. Source field analyses for daily means data and night-time means data have also been carried out in this paper.     

单台地磁夜均值资料研究半年周期变化的电磁响应

用地磁夜均值资料研究半年周期变化的电磁响应 (地磁内外场比值 Q1) ,如夜均值半年周期变化的源场分布符合 P01分布模式 ,则可用单台资料进行计算 ,有利于进行地区性深地磁测深的研究 .本文选择了质量较好的 5个台约 2 6年的连续资料 ,又搜集了可用的全球分布的台站资料进行分析计算 .结果表明 ,从夜均值估算的半年周期变化的 Q1更为可靠 .原因可能是源场模式不同 .一般的日均值资料不符合 P01模式 ,而夜均值资料则比较符合 P01模式 .本文对此作了源场分布的研究 .     

围压对低渗砂岩渗透率有效应力系数的影响

多孔岩石渗透率有效应力系数的取值至今仍没有一致的认识,影响取值的因素较为复杂.为了探索围压对低渗砂岩渗透率有效应力系数的影响,实验上采用较大的围压范围(10MPa～50MPa),选取两块低渗致密砂岩岩样,进行渗透率测试,并利用二元线性回归方法,计算了不同围压组合下的渗透率有效应力系数值,获取了该系数随围压的变化趋势.实验中,两块岩样的渗透率有效应力系数随围压的增加而减小,但各自的减小趋势略有不同.利用Bernabé和Berryman提出的模型,理论上解释了围压对渗透率有效应力系数的影响,并得到渗透率有效应力系数的下限值为岩样孔隙度.尽管渗透率有效应力系数不是一个常数,但可以表示为压差的函数,进而起到简化分析的作用.     

Gorkha (Nepal) earthquake of April 25, 2015: Actual damage,retrofitting measures and prediction by RVS for a few typical structures

This study is an attempt to underline the lack of preparedness and the nature of immediate further measures to be taken for facing a moderate earthquake in Indian subcontinents. Surprisingly, moderate to severe damage was noticed in structures located in hundreds of kilometres away from epicentre during last Gorkha earthquake. In this context, the present study makes an effort to validate a proposed modified rapid visual screening schemes for low cost houses frequently available in India. This may be used extensively for quick vulnerability assessment of a locality. Examples of retrofitting measures for typical buildings presented in this study may be useful for upgrading the valuable structures. Thus this study may be helpful for quick vulnerability assessment and adopting retrofitting measures for identified structures for earthquake prone developing countries.