Numerical Modeling of Transport Properties and Comparison to Laboratory Measurements

Transport properties, such as permeability and electrical conductivity, are important in many geophysical and petroleum applications. The microstructure of a porous medium and physical characteristics of the solid and the fluids that occupy the pore space determine the macroscopic transport properties of the medium. The computation of macroscopic properties from the rock microtomography is becoming an increasingly studied topic. The transport properties are especially difficult to determine at the microscopic scale. The purpose of this paper is to test the applicabilities to numerically calculate the geometrical and transport properties (electrical conductivity, permeability, specific surface area and surface conductivity) of porous, permeable rocks, given the digital CT microtomography images. To better address the relationship between geometrical properties and transport properties, we use a number of artificial low, medium- to high-porosity Finney’s (1970) sphere packs. Numerically calculated transport properties are compared with analytical and empirical equations on the Finney pack. In particular, numerically computed permeability on the Finney pack agrees well with the permeability calculated from the computed formation factor using an empirical relationship on the same structure. This illustrates the consistence of resolving different transport properties on the same structure and the possibility of multiphysics coupling in the future. We also apply all the numerical simulations on the 3D X-ray microtomography of 23.6% porosity Berea Sandstone with 2.8 micron resolution. Numerical calculations of electrical conductivity, permeability and specific surface area on mm[superscript 3] image will be compared to the laboratory measurements with those parameters on cm[superscript 3] core samples. The upscaling issue will be discussed when we compare the numerical results with laboratory measurements at a different scale. We also analyze the image resolution impact on different properties to better understand the discrepancy between numerical computations and laboratory measurements. This paper provides a complete work on the numerical simulations on different physics at different scales. Numerical calculations are compared with analytic, empirical rock physics equations and laboratory measurements.Schlumberger Limite

Press Release: Freedom Summer 1992

Press release for Freedom Summer 1992, a 20-city emergency voter registration effort. Date: June 22, 1992 Box 23 Folder 1

Why women’s domestic violence refuges are not local services

In a context of Localism and public sector cuts in the United Kingdom, women’s domestic violence refuges are experiencing funding cuts and service restrictions. This article presents findings of a research project, quantifying, mapping and conceptualising the journeys women make to escape domestic violence; journeys which often include accessing a women’s refuge. Analysing administrative, survey and interview data it provides evidence of women travelling from everywhere to all types of places to access refuges, and that refuges are distinctively accessed across local authority boundaries. As a result, it is argued that women’s refuges should not be considered, planned and funded as local services; but as regional and national services, hosted locally

Sea Clam Wave Energy Converter

After five years of research, the U.K. wave energy programme is nearing a point of decision on whether to progress towards full-scale testing or to continue on a research basis with reduced funding . The decision will be almost certainly based on the potential economics of wave energy and as a result, several device research teams are firming up on their designs prior to a cost assessment by consultants towards the end of this year. The chosen device or devices will probably have to produce electricity for the national grid at an estimated cost of less than 5 pence per unit at today's prices based on the costings of a 2 GW station located off the Outer Hebrides. Sea Energy Associates Limited and the Coventry (Lanchester) Polytechnic have been involved in the national wave energy programme since 1975, first, on the 1/lOth scale duck programme, (1, 2) and then more recently, on the second generation device known as the Clam (3). The Clam arose out of the need to redl'ce the high costs attributed to the first generation of wave energy devices and represented a new approach to the problem by an experienced team. By defining a sjmple concept which utilised components already identified as attractive, whilst at the same time avoiding known problem areas, the Clam quickly evolved into its 1979 design (3). This design has been tesled at 1/SOth scale in both natural and indoor waves with very satisfying results. Optimisation of the 1979 design has led to further design improvements which reduce the capital cost and increase the overall productivity. The final 1981 design should meet the cost criteria laid down and still retain some potential for further development. This paper discusses the merits of the Clam device and reviews the progress to date. of a floating spine breathe in response to wave forces. This causes air to be forced through self-rectifying turbines into and out of the hollow spine, allowing interchange of air between Clam bags. The randomness of sea wave patterns allows phased operation of the Clam elements, enabling the spine to act as a stable reference body. Typically a 1 OMW generating unit would feature ten Clam elements on a 27 5 m long spine, moored at an angle to tne waves, as illustrated on the cover

Orbit optimization for ASTROD-GW and its time delay interferometry with two arms using CGC ephemeris

ASTROD-GW (ASTROD [Astrodynamical Space Test of Relativity using Optical Devices] optimized for Gravitation Wave detection) is an optimization of ASTROD to focus on the goal of detection of gravitation waves. The detection sensitivity is shifted 52 times toward larger wavelength compared to that of LISA. The mission orbits of the 3 spacecraft forming a nearly equilateral triangular array are chosen to be near the Sun-Earth Lagrange points L3, L4 and L5. The 3 spacecraft range interferometrically with one another with arm length about 260 million kilometers. In order to attain the requisite sensitivity for ASTROD-GW, laser frequency noise must be suppressed below the secondary noises such as the optical path noise, acceleration noise etc. For suppressing laser frequency noise, we need to use time delay interferometry (TDI) to match the two different optical paths (times of travel). Since planets and other solar-system bodies perturb the orbits of ASTROD-GW spacecraft and affect the (TDI), we simulate the time delay numerically using CGC 2.7 ephemeris framework. To conform to the ASTROD-GW planning, we work out a set of 20-year optimized mission orbits of ASTROD-GW spacecraft starting at June 21, 2028, and calculate the residual optical path differences in the first and second generation TDI for one-detector case. In our optimized mission orbits for 20 years, changes of arm length are less than 0.0003 AU; the relative Doppler velocities are less than 3m/s. All the second generation TDI for one-detector case satisfies the ASTROD-GW requirement.Comment: 17 pages, 7 figures, 1 tabl

Dimensionality, topology, energy, the cosmological constant, and signature change

Using the concept of real tunneling configurations (classical signature change) and nucleation energy, we explore the consequences of an alternative minimization procedure for the Euclidean action in multiple-dimensional quantum cosmology. In both standard Hartle-Hawking type as well as Coleman type wormhole-based approaches, it is suggested that the action should be minimized among configurations of equal energy. In a simplified model, allowing for arbitrary products of spheres as Euclidean solutions, the favoured space-time dimension is 4, the global topology of spacelike slices being ${\bf S}^1 \times {\bf S}^2$ (hence predicting a universe of Kantowski-Sachs type). There is, however, some freedom for a Kaluza-Klein scenario, in which case the observed spacelike slices are ${\bf S}^3$. In this case, the internal space is a product of two-spheres, and the total space-time dimension is 6, 8, 10 or 12.Comment: 34 pages, LaTeX, no figure

Costing Annexe To Consultants Preliminary Report

The procedure for costing the Reference Designs of the Wave Power Devices is described in Chapter 3 of the Consultant's Preliminary Report. The detailed breakdown of the prices determined for each Device, together with tabulated comparisons of the data received from contractors, is given as an Appendix to this Cost Annexe. The following tabulated summaries cover the overall capital cost of the construction of a 200 MW installed capacity power station for each Device. They should not be taken outside the context of the Consultants Preliminary Report, in which the reservations to be placed both on the preliminary Reference Designs and on the preliminary costing exercise are clearly stated. During this study, time did not permit the exploration of the many avenues which are available for potential cost reduction both by redesign and the study of alternative construction procedures. In particular there has been no opportunity for discussion of the costing exercise with the Device Teams. However, a study of the cost breakdowns indicates areas in each Device where cost savings should be achieved by appropriate design changes or more detailed analysis