ON THE PERFECT SQUARES IN SMARAtXffiACHE CONCATENATED SQUARE SEQUENCE

Let n be positive integer, and let sen) denote the n-th Smarandache concatenated squre number

Numerical modelling of groundwater flow and radioactive waste migration: Sellafield, England

Sellafield in NW England was proposed as a candidate site for subsurface disposal in the UK of Intermediate Level radioactive Waste (ILW). Part of the concept of such a site is that the geosphere functions as one of many barriers against serious leakage. Assessment of overall performance requires predictions of the groundwater flow, which may transport radionuclide into shallow aquifers, or to the surface. This thesis develops a 2-D model, which simulate subsurface fluid flow as a means to aid prediction into the far future. The software uses the finite element method, and is an adaptation of OILGEN (Garven 1989). This permits coupling of rock properties, water properties, and flow resulting from differences of potential- including head, density and heat. Mass transport computations are based on a random walk particle tracking model. Data for this thesis was derived from an extensive site investigation program undertaken by UK NIREX. Conceptually, the regional flow system consists of rainwater falling on 1,000m high ground of the Cumbrian mountains and percolating into the Borrowdale Volcanic Group (BVG), passing westwards by deep flow and returning upwards through the repository site (PRZ), before discharge into overlying sediments and into the Irish Sea. A regional cross section (WSW to ENE) was constructed 115km long and 7.5km deep. This is much longer and deeper than previous studies of hydrogeology in this area. The objective was to reproduce the regional flow and local flow at the repository site. Modelling was carried out progressively, investigating the effects of rock permeability, geometry, anisotropy, faults, salinity and mesh geometry. The approach was to perform a very extensive and prolonged series of sensitivity tests and to adjust each parameter independently to achieve the best fit of predicted groundwater head profiles to head profiles measured in Boreholes 3, 10A and 2. Two sets of best-fit parameters were derived from this calibration exercise. A second stage of model validation used the two calibrated models to predict the streamlines and residence ages of groundwater in the PRZ. These were compared to the in-situ measured chemistry and salinity of groundwater, and to the measured mean residence age of the groundwater. Only one suite of parameters in the modelling was compatible with both head and residence age measured data. This validated model is taken to be the best representation of the natural regional flow system and to simulate the release of radionuclides from the repository and their pathways towards the surface transported by moving groundwater. Modelling shows three flow regimes, similar to measured geochemical data: Shallow Flow (high flux); Inland Flow (small flux); Irish Basin (very small flux). Best fit model parameters are close to the median rock permeability measured in the field. BVG permeability is 0.12m/yr and flow rate at the repository site is 1.0m/yr. Recharge is 16km east of the repository. Critical controls on flow are >2km deep permeabilities of Eskdale Granite and Skiddaw Slate, which have not been sampled by boreholes. Water residence age at the repository is predicted as 0.14-0.15Ma by both streamline and dispersion methods; this compares well with measured 0.03-1.5Ma ages. Leachate from the repository reaches the Calder Sandstone 400m deep aquifer after 25,000yr and the Irish Sea bed at 50,000-80,000yr, 3km west of the repository. It is concluded that the geosphere at this PRZ does not greatly assist performance. Previous local models have not correctly considered very deep flow. A PRZ is better sited on the inflow end, not the outflow end, of a regional groundwater system

Imaged based fractal characterization of micro-fracture structure in coal

We acknowledge financial support from the National Natural Science Foundation of China (41830427; 41472137), the Petro China Innovation Foundation (2018D-5007-0101), the Key research and development project of Xinjiang Uygur Autonomous Region (2017B03019-1), the Royal Society Edinburgh and National Natural Science Foundation China (NSFC 41711530129), and the Foreign Experts’ Recruiting Program from the State Administration of Foreign Experts Affairs P.R. China.Peer reviewedPostprin

Multi-scale Image-Based Pore Space Characterisation and Pore Network Generation : Case Study of a North Sea Sandstone Reservoir

The authors would like to thank Anasuria Operating Company Ltd (AOC) for making available the rock samples for analysis. SEM imaging was performed at the University of Aberdeen Centre for Electron Microscopy, Analysis and Characterisation (ACEMAC). We would like to thank John Still for invaluable assistance in the SEM imaging work. The authors acknowledge the very helpful comments from three anonymous reviewersPeer reviewedPostprin

Improvements to the fracture pipe network model for complex 3D discrete fracture networks

Acknowledgments Chenhui Wang thanks the financial support from China Scholarship Council (CSC) for his Ph.D. study. The authors thank the discussions of the real-world case study with Dr Yu Jing at the University of New South Wales. Open access via Wiley agreementPeer reviewedPublisher PD

Effects of Ultrasound on the Removal of Emulsion Plugging in Oil Reservoirs

The authors are grateful to the Tertiary Education Trust Fund (TETFund) of Nigeria and University of Aberdeen UK, for providing the laboratory facilities required to complete this research.Peer reviewedPublisher PD

Influences of Random Surface Waves on the Estimates of Wind Energy Input to the Ekman Layer in the Antarctic Circumpolar Current Region

Sea surface waves significantly affect the wind energy input to the Ekman layer in the upper ocean. In the study, we first incorporated the wave-induced Coriolis-Stokes forcing, the reduction of wind stress caused by wave generation, and wave dissipation into the classical Ekman model to investigate the kinetic energy balance in the wave-affected Ekman layer. Then, both the theoretical steady state solution for the idealized condition and the nonsteady state solution for the realistic ocean were derived. Total energy input to the wave-affected Ekman layer includes the wind stress energy input and the wave-induced energy input. Based on the WAVEWATCH III model, the wave spectrum was simulated to represent realistic random directional wave conditions. The wind stress energy input and the wave-induced energy input to the wave-affected Ekman layer in the Antarctic Circumpolar Current in the period from 1988 to 2010 were then calculated. The annual mean total energy input in the Antarctic Circumpolar Current region was 402.5 GW and the proportions of the wind stress energy input and the wave-induced energy input were, respectively, 85% and 15%. Particularly, total energy input in the Antarctic Circumpolar Current in the wave-affected Ekman layer model was 59.8% lower than that in the classical Ekman model. We conclude that surface waves play a significant role in the wind energy input to the Ekman layer

Applying Green AI methods to Digital Rock Technology workflows

Peer reviewedPublisher PD