Mathemateg a Ffiseg / Mathematics & Physics
http://hdl.handle.net/2160/14
2016-02-11T19:17:14Z
2016-02-11T19:17:14Z
Numerical simulation of hydraulic fractures: various leak-off regimes and multifracturing
Kusmierczyk, Piotr
http://hdl.handle.net/2160/30574
2016-01-12T11:29:26Z
2015-01-01T00:00:00Z
Numerical simulation of hydraulic fractures: various leak-off regimes and multifracturing
Kusmierczyk, Piotr
2015-01-01T00:00:00Z
Classification of book spreads in PG(5, 2)
McDonough, Thomas
Shaw, R.
Topalova, S.
http://hdl.handle.net/2160/30066
2016-02-02T11:54:04Z
2013-01-01T00:00:00Z
Classification of book spreads in PG(5, 2)
McDonough, Thomas; Shaw, R.; Topalova, S.
We classify all line spreads S21 in PG(5, 2) of a special kind, namely those which are book spreads. We show that up to isomorphism there are precisely nine different kinds of book spreads and describe the automorphism groups which stabilize them. Most of the main results are obtained in two independent ways, namely theoretically and by computer. © 2013 Università del Salento.
McDonough, T., Shaw, R., Topalova, S. (2013). Classification of book spreads in PG(5, 2). Note di Matematica, 33 (2), 43-64
2013-01-01T00:00:00Z
Optical Spectroscopy Instrumentation for the Characterisation of Wide Band Gap Materials
Cross, Rachel Elizabeth
http://hdl.handle.net/2160/29790
2015-10-16T02:04:16Z
2015-01-01T00:00:00Z
Optical Spectroscopy Instrumentation for the Characterisation of Wide Band Gap Materials
Cross, Rachel Elizabeth
This thesis presents work undertaken in the design, build, characterisation and first results of a new instrument for the optical characterisation of wide band gap materials by their luminescence.
Optical spectroscopy is a promising method for investigating material properties due to its non-destructive nature and high sensitivity. The ability to relate to a material’s optical properties to its structure and composition is highly desirable in Materials Physics applications. Spatial information is lost when measuring heterogeneous samples due to the convolution of spectral information from different regions within the sample. Though the combination of imaging and spectroscopy spatially resolved data can be a. In this work the spectro-radiometrically calibrated instrument HeLIOS (Hyperspectral Imaging for Optical Spectroscopy) is introduced. This instrument has allowed the collection of spatially resolved radiometrically calibrated photoluminescence investigations on a number of wide band gap materials.
2015-01-01T00:00:00Z
Analysis of a model for foam improved oil recovery
Grassia, P.
Mas-Hernández, E.
Shokri, N.
Cox, S. J.
Mishuris, G.
Rossen, W. R.
http://hdl.handle.net/2160/14173
2016-02-02T11:54:05Z
2014-07-01T00:00:00Z
Analysis of a model for foam improved oil recovery
Grassia, P.; Mas-Hernández, E.; Shokri, N.; Cox, S. J.; Mishuris, G.; Rossen, W. R.
During improved oil recovery (IOR), gas may be introduced into a porous reservoir filled with surfactant solution in order to form foam. A model for the evolution of the resulting foam front known as ` pressure-driven growth'is analysed. An asymptotic solution of this model for long times is derived that shows that foam can propagate indefinitely into the reservoir without gravity override. Moreover, `pressure-driven growth' is shown to correspond to a special case of the more general `viscous froth' model. In particular, it is a singular limit of the viscous froth, corresponding to the elimination of a surface tension term, permitting sharp corners and kinks in the predicted shape of the front. Sharp corners tend to develop from concave regions of the front. The principal solution of interest has a convex front, however, so that although this solution itself has no sharp corners (except for some kinks that develop spuriously owing to errors in a numerical scheme), it is found nevertheless to exhibit milder singularities in front curvature, as the long-time asymptotic analytical solution makes clear. Numerical schemes for the evolving front shape which perform robustly (avoiding the development of spurious kinks) are also developed. Generalisations of this solution to geologically heterogeneous reservoirs should exhibit concavities and/or sharp corner singularities as an inherent part of their evolution: propagation of fronts containing such `inherent'singularities can be readily incorporated into these numerical schemes.
Grassia, P., Mas-Hernández, E., Shokri, N., Cox, S. J., Mishuris, G., Rossen, W. R. (2014). Analysis of a model for foam improved oil recovery. Journal of Fluid Mechanics, 751, 346-405
2014-07-01T00:00:00Z