Principles for selecting a list of reference radio sources for a celestial coordinate system

Time series of the coordinates of radio sources defining the celestial coordinate frame are analyzed. Methods for selecting such sources so as to enhance the stability of the frame are considered. Some of these sources, including so-called “defining” sources, demonstrate significant proper motions. Since the stability of the celestial coordinate frame is determined by an absence of global rotation relative to the defining sources (no net rotation), variation in their coordinates will lead to a rotation of the axes of the celestial coordinate frame. The parameters of this rotation are calculated for two physical models for the motions of extragalactic radio sources. The motions displayed by the first group of sources are linear and uniform. Since the apparent speeds of radio sources are often close to, and sometimes exceed, the speed of light, it is supposed that such radio sources have relativistic jets or plasma clouds that move with speeds roughly equal to the speed of light. The observed uniform, linear motion can then be explained by precession of the jet. The second group of sources display non-linear motions, interpreted as a manifestation of the acceleration of matter by the jet. It is assumed that a cloud of particles that moves into the path of the jet is accelerated to relativistic speeds by the jet. A list of sources that should form a very stable coordinate system for several decades into the future is composed based on these two models.     

横观各向同性土体有限层分析

首先概括介绍了三维横观各向同性比奥固结有限层分析方法,并采用已经发表的4个算例结果来考证所编制的计算程序,然后详细地讨论了横观各向同性对瞬时沉降、最终沉降和固结性状的影响,发现横观各向同性对计算结果的影响分别高达33 %,24 % 和40 %,最后给出了一些对工程实践有一定参考价值的计算图表。     

Determination of the homogeneous magnitude system magnitudes in seismological practice

Routine determination of network magnitudes by means of the Eurasian homogeneous magnitude system (HMS) is described and tested on a selection of recent shallow earthquakes. The HMS earthquake magnitudes appear to be more accurate and more reliable than the conventional earthquake magnitudes used in the present seismological practice. A preliminary investigation of correlations between magnitudes determined from different wave types shows a possible dependence of the correlation on the type of focal mechanism of earthquakes.     

气压对观测井水位的影响及校正方法

地下水监测能为有效管理地下水资源提供重要信息。大气压力对观测井水位有着重要影响,正确地分析这种影响可以有效判别地下水的流向,判断含水层的性质、识别井筒存储效应（well bore storage effects）和井薄壁效应(well skin effects), 计算包气带中空气的扩散度等。随着现代化监测仪器的推广使用,高质量的监测数据为分析气压对观测井水位的影响提供了基础和保障。系统分析了不同类型含水层中井水位对大气压力的响应模式,并对校正气压对水位影响的方法进行了分析和讨论。最后,以北京平原区两口监测井为例,运用多元回归反卷积方法分析了气压对井水位的影响,并对井水位进行校正。结果表明该方法能有效地分析和校正观测井水位中的气压影响。     

An architecture for consolidating multidimensional time-series data onto a common coordinate grid

Consolidating measurement data for use by data models or in inter-comparison studies frequently requires transforming the data onto a common grid. Standard methods for interpolating multidimensional data are often not appropriate for data with non-homogenous dimensionality, and are hard to implement in a consistent manner for different datastreams. These challenges are increased when dealing with the automated procedures necessary for use with continuous, operational datastreams. In this paper we introduce a method of applying a series of one-dimensional transformations to merge data onto a common grid, examine the challenges of ensuring consistent application of data consolidation methods, present a framework for addressing those challenges, and describe the implementation of such a framework for the Atmospheric Radiation Measurement (ARM) program.     

Development of a graphic database for an analytical information system for rapid estimation of gold deposits on the basis of choice of a reference object

This study is aimed at substantiation of the need for use of properties of graphic information in rapid estimation of deposits that are the most similar to reference objects provided with a graphic representation of features and geological situations unknown at a poorly studied expertized object. A technology of graphic database compilation for use in an analytical information system of analogue search is proposed. The system of rapid estimation of gold deposits on the basis of choice of a reference object is supplemented for the first time by a graphic database containing geological data that are necessary for analysis of deposits but cannot be presented in a text or digital form. Taking into consideration the wide development of Internet technologies, the attached HTML file technology, which allows storage of an unlimited number of raster images, was chosen for the control system.     

Correlation of well logs as a multidimensional optimization problem

We consider a variant of automatic correlation between well sections based on construction of multidimensional functions of differences between fragments of logs. The solution is obtained either by successive correlation between the boundaries based on the projective model of Haites and definition of the boundary position at the minimum of the difference function or by construction of the lines of optimal trajectories on a 2D Zhekovskii’s plot. These algorithms are implemented as a program package for original interpretation of well data and as a plug-in for the automatic correlation module of the Schlumberger Petrel software using the Ocean development tools.© 2015, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.     

Estimation of the acceleration of the solar-system barycenter relative to a system of reference quasars

It is shown that geodetic VLBI observations can be used to estimate the external acceleration of the barycenter of the solar system. This relies on the fact that, in special relativity, the acceleration of the motion of a coordinate origin relative to reference points leads to a drift in the secular aberration, manifest as systematic proper motions of the reference points in the direction of the acceleration vector. The VLBI time-delay equation is modified such that the acceleration vector appears in explicit form. Formulas for a new form of the fundamental VLBI equation and its partial derivative with respect to the acceleration are presented.     

Formulation, application and evaluation of a stack emission model for coal-based power stations

Estimation of coal power plant emissions is a vital step to visualise emission trends with respect to specific policy implementations and technological interventions so that their effectiveness in terms of emission reductions and ambient air quality improvement can be quantitatively assessed. However, research work concerning stack emission estimations specifically for coal power plants in India is limited. To bridge the present gap, we present a plant-specific multi-year and multi-parameter Coal Power Stack Emission Model. This model has been developed to explore current and historical annual stack emissions from a coal-based thermal power plant taking into account essential variables such as coal characteristics, process attributes and control equipment aspects, which can significantly influence the stack emissions. This study concentrates on development of Coal Power Stack Emission model and its application for the estimation of plant and year-specific emission factors and stack emissions for a coal-based power plant at Badarpur, New Delhi, for the period of 2000–2008. The validation of Coal Power Stack Emission model has also been successfully carried out by comparing the trends of percentage change in annual emission estimates and observed ambient air concentrations of total suspended particles, PM₁₀ and sulphur dioxide at two nearby air quality monitoring stations, namely Siri Fort and Nizamuddin.     

Using multidimensional analysis and information functions for macro description of European natural complexes in the second part of the Late Pleistocene and the Holocene

This article analyzes the effect of geographic factors on variations in the species diversity of mammals and plants for the European territory. Multidimensional analysis and a number of information parameters have been applied for the first time, which allowed identifying objective indicators of mammal and plant diversity for different time periods in the Late Pleistocene and the Holocene.     

Estimation of a multidimensional covariance function in case of anisotropy

A model of a multivariate covariance function with an ellipsoidal directional correlation scale has been developed. The axes of the ellipsoidal scale are related to the eigenvalues and eigenvectors of a matrix B which characterizes the ellipsoid of the range of influence. The matrix B is found to be related to a matrix T which can be estimated directly from sparse sampling data and can be used to determine estimates of the matrix B. The method has been applied to both two-dimensional and three-dimensional cases. The numerical results show that the satisfactory accuracy is obtained with sparse sampling data from an anisotropic random function.     

Green's functions for a fully coupled thermoporoelastic material

The Green's functions for a set of fully coupled linear equations governing thermal consolidation of a homogeneous isotropic material are presented. The Green's functions are evaluated for one, two and three spatial dimensions, and in the Laplace and real-time domains. The Green's functions are employed in a boundary integral analysis of a simple problem to demonstrate the influence of full coupling on the field quantities.     

Human health risk as a basis for prioritizing air quality monitoring stations in a megacity: a case study

Arabian Journal of Geosciences - The Ahnet and Tin Zaouatine terranes are located in the southern sector of the Algerian Desert and are part of the Tuareg Shield, which was built up during...     

LPI-based approach for calibrating the severity of liquefaction-induced failures and for assessing the probability of liquefaction surface evidence

Liquefaction Potential Index (LPI) is used as an assessing tool of liquefaction susceptibility. Based on the existing correlation of the LPI values with the liquefaction potential of a site, liquefaction hazard maps have been compiled. The evaluation of liquefaction susceptibility of the soil layers that had been taken into account for the calculation of LPI value, on the existing classifications, was based on the “Chinese criteria”. However, Seed et al. [Seed, R.B., Cetin, K.O., Moss, R.E.S., Kammerer, A.M., Wu, J., Pestana, J.M., Riemer, M.F., Sancio, R.B., Bray, J.D., Kayen, R.E., Faris, A., 2003. Recent advances in soil liquefaction engineering: a unified and consistent framework. 26th annual ASCE L.A. Geotechnical Spring Seminar, Long Beach, California. 71 pp.] concluded that those criteria are conservative and proposed a modification of them.The basic aim of this paper is to examine the impact of these modifications to the existing LPI-based calibrations of severity scale of liquefaction-induced failures and to propose a new one if it is needed, using box–whisker plot method. The data set that was analyzed is compiled by borings with SPT from liquefied and non-liquefied sites in Taiwan, in Turkey and in Greece.Moreover, a LPI-based formula is proposed, as an outcome from the application of logistic regression analysis to the data set, which can be used for predicting the liquefaction surface occurrence. In addition, a discriminant function is suggested for classifying a site as liquefiable or not. In this approach, the LPI and the thickness of the non-liquefiable cap layer are taken into account as the classification parameters.     

Scaling laws for hydraulic fractures driven by a power-law fluid in homogeneous anisotropic rocks

This study investigates parametric space of solutions for a planar hydraulic fracture propagating in a homogeneous anisotropic rock. It is assumed that the fracture has an elliptical shape and is driven by a power-law fluid. The purpose of this study is to investigate the influence of anisotropy and power-law fluid rheology on the parametric space of solutions. Rock anisotropy is represented by having two values of fracture toughness, one in the vertical direction and another one in the horizontal direction. Similarly, the effect of elastic anisotropy is approximated by using two different effective elastic moduli in the vertical and horizontal directions. In contrast to the isotropic case, for which there are four limiting solutions, the problem for anisotropic rocks features six different limiting cases. These cases represent competition between toughness and viscosity in the vertical and horizontal directions and competition between fluid storage inside the fracture and fluid leak-off into formation. Approximate expressions for the limiting solutions are obtained using global volume balance and tip asymptotic solutions. Despite the developed solutions rely on a series of approximations, they precisely capture all the scaling laws associated with the problem. Zones of applicability of these limiting solutions are calculated, and their dependence on the problem parameters is investigated.     

A modified inverse procedure for calibrating parameters in a land subsidence model and its field application in Shanghai,China

Land-subsidence prediction depends on an appropriate subsidence model and the calibration of its parameter values. A modified inverse procedure is developed and applied to calibrate five parameters in a compacting confined aquifer system using records of field data from vertical extensometers and corresponding hydrographs. The inverse procedure of COMPAC (InvCOMPAC) has been used in the past for calibrating vertical hydraulic conductivity of the aquitards, nonrecoverable and recoverable skeletal specific storages of the aquitards, skeletal specific storage of the aquifers, and initial preconsolidation stress within the aquitards. InvCOMPAC is modified to increase robustness in this study. There are two main differences in the modified InvCOMPAC model (MInvCOMPAC). One is that field data are smoothed before diagram analysis to reduce local oscillation of data and remove abnormal data points. A robust locally weighted regression method is applied to smooth the field data. The other difference is that the Newton-Raphson method, with a variable scale factor, is used to conduct the computer-based inverse adjustment procedure. MInvCOMPAC is then applied to calibrate parameters in a land subsidence model of Shanghai, China. Five parameters of aquifers and aquitards at 15 multiple-extensometer sites are calibrated. Vertical deformation of sedimentary layers can be predicted by the one-dimensional COMPAC model with these calibrated parameters at extensometer sites. These calibrated parameters could also serve as good initial values for parameters of three-dimensional regional land subsidence models of Shanghai.     

Application of the homogeneous function and modeling methods for reconstruction of a Tibetan geological section from a travel-time inversion

New structures were revealed in Central Tibet after reinterpretation of the first arrivals of refracted seismic waves along the INDEPTH III profile. The method that was used for travel-time inversion is the numerical generalization of the Herglotz-Wiechert formula for the case of a 2D inhomogeneous medium (the homogeneous-function method). The new section shows that the Bangong-Nujiang Suture (BNS) is a contact in the upper crust, while its continuation in the middle crust is a listric thrust; at the top of the lower crust, which has risen to a 32-km depth in the northern part of the section, this thrust become gentler. Below the middle crust top, a layer with a lower velocity of seismic waves is found. The middle crust is deformed and forms oblique southward listric thrusts. In the upper crust south of the BNS, higher-velocity zones (probable zones of magmatism) are distinguished. North of the BNS, undisturbed outlines of the structures are observed.     

水化台站今后发展的几点想法

本文通过分析当今水化台站面临的观测水点及观测手段越来越少、经费普遍紧张、分析预报水平难以提高等问题及其解决办法 ,进而提出了台站今后工作的努力方向。     

Vibration of a homogeneous half-space of arbitrary Poisson's ratio interrupted by a frictionless plane

The work presents an exact expression for the Hankel transform of the surface displacement of a rigid circular body performing harmonic vertical vibrations on a homogeneous elastic half-space of arbitrary Poissn'S ratio interrupted at some depth by a frictionless horizontal plane. The limiting case of the uninterrupted half-space is recovered in each of the extreme cases when the frictionless plane coincides with the surface or sinks to an infinite depth. Furthermore, the static case is derived in the limiting case of zero frequency and it is shown that the result agrees with the limiting case of zero gradient shear modulus variation for the static case of the incompressible non-homogeneous half-space. It is also established that Poisson'S ratio effect is linear, and the important proposition is again sustained that only surface shear modulus dominates vibrations on elastic media whereas any other factor such as the interruption of the frictionless plane as in the present case, merely constitutes a negligible secondary parameter.