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The purpose of this paper is to present a time‐domain technique to compute the electromagnetic wave field and to reconstruct the permittivity and electric conductivity profile of a one‐dimensional slab of finite length.

The forward scattering problem is solved by a Green's function formulation to generate synthetic data that are used as a testbed for the inversion scheme. The inverse scattering problem is solved by reconstructing the unknown permittivity and electric conductivity profile of the medium with the help of an invariant embedding method.

The Green's operator maps the incident field on either side of the medium to the field at an arbitrary observation point inside the slab and hence, the internal fields can be computed directly without computing the wave field throughout the entire medium. The invariant embedding method requires a finite time trace of reflection data and therefore it is suitable for reconstructing the material parameters in real‐time.

The implemented methods have been validated against synthetic and measured time domain reflectometry data.

This paper fulfils an identified need to determine unknown one‐dimensional profiles and thus plays an important role in electromagnetics, non‐destructive testing, and geophysics.

Presents the development and implementation of a four‐dimensional variational (4D‐var) data assimilation technique for a comprehensive Eulerian chemistry‐transport model. The method aims at analysing the chemical state of the atmosphere on the basis of trace gas observations with arbitrary distribution in time and space, a chemistry‐transport model, and a priori knowledge as available from climatological records or preceding model runs. The model under consideration is the University of Cologne EURAD‐CTM2 with the full RADM2 gas phase mechanism. Describes the storage and recalculation strategy of a parallel implementation of the 4D‐var method and first experiences of its performance, when model generated data are provided as artificial observations. The problem of pre‐scaling the minimization problem is discussed in some detail. It is found that the algorithm is well suited to adapt the model trajectory to the observation data.

The purpose of the paper was the application of computational fluid dynamics (CFD) techniques in fluid flow using Maxwell’s equation for partial slip modelling, estimating the flow parameters, and selecting tangential momentum accommodation coefficient (TMAC) for tight rock samples in permeability calculations.

The paper presents a numerical analysis of fluid flow in a low-porosity rock sample by using CFD. Modelling results allowed to determine mass flow rates in a rock sample and to calculate permeability values using a modified Darcy’s equation. Three-dimensional (3D) geometrical model of rock sample generated using computed X-ray tomography was used in the analysis. Steady-state calculations were carried out for defined boundary conditions in the form of pressure drop. The simulations were applied taking into account the slip phenomenon described by Maxwell’s slip model and TMAC.

Values of permeability were calculated for different values of TMAC, which vary from 0 to 1. Results in the form of gas mass flow rates were compared with the measured value of permeability for rock sample, which confirmed the high accuracy of the presented model.

Calculations of fluid flow in porous media using CFD can be used to determine rock samples’ permeability. In slip flow regime, Maxwell’s slip model can be applied and the empirical value of TMAC can be properly estimated.

This paper presents the usage of CFD, Maxwell’s equation for partial slip modelling, in fluid flow mechanism for tight rock samples. 3D geometric models were generated using created pre-processor (poROSE software) and applied in the raw form for simulation.

Recent work has shown that potentially useful predictions of the circulation of library materials can be made which do not require very restrictive assumptions about underlying probability distributions. In the same spirit, we here consider one of the classic problems of bibliometrics, viz. predicting the number of ‘new’ journals carrying ‘relevant’ articles in the future, using both established parametric approaches and the newer, empirical methods.

In this chapter, we present our ongoing efforts in developing and sustaining interdisciplinary STEM undergraduate programs at North Carolina A&T State University (NCA&T) – a state-supported HBCU and National Science Foundation (NSF) Historically Black Colleges and Universities Undergraduate Program (HBCU-UP) Institutional Implementation Project grantee. Through three rounds of NSF HBCU-UP implementation grants, a concerted effort has been made in developing interdisciplinary STEM undergraduate research programs in geophysical and environmental science (in round 1), geospatial, computational, and information science (in round 2), and mathematical and computational biology (in round 3) on NCA&T campus. We first present a brief history and background information about the interdisciplinary STEM undergraduate research programs developed and sustained at NCA&T, giving rationales on how these programs had been conceived, and summarizing what have been achieved. Next we give a detailed description on the development of undergraduate research infrastructure including building research facilities through multiple and leveraged funding sources, and engaging a core of committed faculty mentors and research collaborators. We then present, as case studies, some sample interdisciplinary research projects in which STEM undergraduate students were engaged and project outcomes. Successes associated to our endeavor in developing undergraduate research programs as well as challenges and opportunities on implementing and sustaining these efforts are discussed. Finally, we discuss the impact of well-structured undergraduate research training on student success in terms of academic performance, graduation rate and continuing graduate study, and summarize many of the learnings we have gained from implementation and delivery of undergraduate research experiences at HBCUs.

The University of Illnois Information Retrieval Research Laboratory contracted with the United States Federal Emergency Management Agency (FEMA) to identify and analyze word‐oriented databases of potential relevance to FEMA. A subject profile technique was used to measure how many potentially relevant citations were found in selected databases, thus allowing a ranking and comparison of databases for the multidisciplinary field of emergency management. “Distribution of Citations in Databases in a Multidisciplinary Field” describes the ranking of databases relevant to emergency management and demonstrates the applicability of Bradford's law of scatter to citations in databases. This article describes an experiment to compare the subject profile technique used in the FEMA project to another common database coverage evaluation technique — the ‘bibliography’ or ‘review article’ technique. Although the two techniques have slightly different purposes, they can both be used to compare the coverage of databases in a particular subject area. This study shows the subject profile technique to be less costly and less time consuming.

This paper reports on the successful introduction of a sophisticated online catalogue system at the library of the Scott Polar Research Institute, Cambridge, using the Muscat program package. The system provides to both end‐users and library staff a choice between boolean searching on keywords and access using relevance feedback based on free text in English, mixed with UDC classification numbers. The system is implemented on an IBM 3084 computer. Significant benefits from the application of relevance feedback are reported with 10,000 records on file.

The purpose of this paper is to develop a new finite difference method for solving the seismic wave propagation in fluid-solid media, which can be described by the acoustic and viscoelastic wave equations for the fluid and solid parts, respectively.

In this paper, the authors introduced a coordinate transformation method for seismic wave simulation method. In the new method, the irregular fluid–solid interface is transformed into a horizontal interface. Then, a multi-block coordinate transformation method is proposed to mesh every layer to curved grids and transforms every interface to horizontal interface. Meanwhile, a variable grid size is used in different regions according to the shape and the velocity within each region. Finally, a Lebedev-standard staggered coupled grid scheme for curved grids is applied in the multi-block coordinate transformation method to reduce the computational cost.

The instability in the auxiliary coordinate system caused by the standard staggered grid scheme is resolved using a curved grid viscoelastic wave field separation strategy. Several numerical examples are solved using this new method. It has been shown that the new method is stable, efficient and highly accurate in solving the seismic wave equation defined on domain with irregular fluid–solid interface.

First, the irregular fluid–solid interface is transformed into a horizontal interface by using the coordinate transformation method. The conversion between pressures and stresses is easy to implement and adaptive to different irregular fluid–solid interface models, because the normal stress and shear stress vanish when the normal angle is 90° in the interface. Moreover, in the new method, the strong false artificial boundary reflection and instability caused by ladder-shaped grid discretion are resolved as well.

It is shown that there is no ambiguity in Bradford's theory of distribution. Starting with the two basic postulates laid down by Bradford, a mathematical expression is derived such that its curve agrees with the experimentally plotted data.

The dynamics of fluid - saturated porous rock is a particularly interesting problem in geophysics and hydrology, nevertheless it is very important in environmental protection as well since it is able to describe, in a lot of situations, the propagation of pollutant substances dissolved in porous environmental matrices. It has been show that, for these systems, the nonlinear effects can be very important to consider. In this paper we'll discuss two novel approaches to the study of the above dynamics: one based on constitutive and conservation equations, the other considering the mass - balance equations for the solute flow and for adsorption rate of solute on the poroelastic matrix. We have shown the first model correctly describes the nonlinear behavior of the fluid pore pressure and pollutants concentration while the second gives the nonlinear term describing advection of which some numerical solutions has been calculated.