Preprints
Filtering by Subject: Engineering
The role of natural clays in the sustainability of landfill liners
Published: 2020-01-10
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Geochemistry, Geology, Geotechnical Engineering, Physical Sciences and Mathematics
Engineered synthetic liners on their own are not the ideal solution to protect land, water and living beings against landfill leachate pollution. Despite their impermeability, engineered liners are susceptible to fail during installation and after a few years of landfill operation, and have no attenuation properties. Conversely, natural clay liners can attenuate leachate pollutants by reactions [...]
A web application for hydrogeomorphic flood hazard mapping
Published: 2020-01-09
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Hydraulic Engineering, Hydrology, Physical Sciences and Mathematics
A detailed delineation of flood-prone areas over large regions represents a challenge that cannot be easily solved with today’s resources. The main limitations lie in algorithms and hardware, but also costs, scarcity and sparsity of data and our incomplete knowledge of how inundation events occur in different river floodplains. We showcase the implementation of a data-driven web application for [...]
Single-blind test of airplane-based hyperspectral methane detection via controlled releases
Published: 2020-01-08
Subjects: Education, Engineering, Other Engineering
Methane leakage from point sources in the oil and gas industry is a major contributor to global greenhouse gas emissions. The majority of such emissions come from a small fraction of ``super-emitting" sources. We evaluate the emission detection and quantification capabilities of Kairos Aerospace’s airplane-based hyperspectral imaging methane emission detection system for methane fluxes of 18 to [...]
Goal-Oriented Error Estimation and Mesh Adaptation for Shallow Water Modelling
Published: 2019-12-31
Subjects: Applied Mathematics, Computer Sciences, Engineering, Non-linear Dynamics, Numerical Analysis and Computation, Numerical Analysis and Scientific Computing, Partial Differential Equations, Physical Sciences and Mathematics
Numerical modelling frequently involves a diagnostic quantity of interest (QoI) - often of greater importance than the PDE solution - which we seek to accurately approximate. In the case of coastal ocean modelling the power output of a tidal turbine farm is one such example. Goal-oriented error estimation and mesh adaptation can be used to provide meshes which are well-suited to achieving this [...]
Scheduling of Twin Telescopes and the Impact on Troposphere and UT1 Estimation
Published: 2019-12-13
Subjects: Earth Sciences, Engineering, Other Earth Sciences, Physical Sciences and Mathematics
Recently, several VGOS twin telescopes in Europe were completed. We examine the use of VGOS twin telescopes by a new scheduling approach. This ap- proach is based on integer linear programming and cre- ates uniform distributed observations over time. Sev- eral VLBI intensive sessions are rescheduled involving the VGOS twin telescopes and the impact on the tropo- sphere and UT1 estimation is [...]
Fluid surface coverage showing the controls of rock mineralogy on the wetting state
Published: 2019-12-13
Subjects: Chemical Engineering, Earth Sciences, Engineering, Petroleum Engineering, Physical Sciences and Mathematics
The wetting state is an important control on flow in subsurface multi fluid phase systems, e.g., carbon storage and oil production. Advances in X-ray imaging allow us to characterise the wetting state using imagery of fluid arrangement within the pores of rocks. We derived a model from equilibrium thermodynamics relating fluid coverage of rock surfaces to wettability and fluid saturation. The [...]
The interplay between clay fabric and mechanical response of deep-seated landslides
Published: 2019-12-05
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geology, Geotechnical Engineering, Physical Sciences and Mathematics
Deep-seated landslides are amongst the most devastating natural hazards on earth, typically involving a rigid rock mass sliding over a weak, clayey shear-band. The mechanical response of this shear-band to the loading of the overburden is therefore critical for the stability of a landslide. We hereby show that this mechanical response is strongly linked to the mineralogy and microstructure of the [...]
Optical wave gauging using deep neural networks
Published: 2019-12-04
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geomorphology, Physical Sciences and Mathematics
We develop a remote wave gauging technique to estimate wave height and period from imagery of waves in the surf zone. In this proof-of-concept study, we apply the same framework to three datasets: the first, a set of close-range monochrome infrared (IR) images of individual nearshore waves at Duck, NC, USA; the second, a set of visible (i.e. RGB) band orthomosaics of a larger nearshore area near [...]
Urban Near-surface Seismic Monitoring using Distributed Acoustic Sensing
Published: 2019-11-27
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Physical Sciences and Mathematics
Urban subsurface monitoring requires high temporal-spatial resolution, low maintenance cost, and minimal intrusion to nearby life. Distributed acoustic sensing (DAS), in contrast to conventional station-based sensing technology, has the potential to provide a passive seismic solution to urban monitoring requirements. Based on data recorded by the Stanford Fiber Optic Seismic Observatory, we [...]
Effects of off-fault inelasticity on near-fault directivity pulses
Published: 2019-11-27
Subjects: Civil and Environmental Engineering, Engineering, Geotechnical Engineering
Near-fault motion is often dominated by long-period, pulse-like particle velocities with fault-normal polarization that, when enhanced by directivity, may strongly excite mid- to high-rise structures. We assess the extent to which plastic yielding may affect amplitude, frequency content, and distance scaling of near-fault directivity pulses. Dynamic simulations of 3D strike-slip ruptures reveal [...]
Simulating Electropulse Fracture of Granitic Rock
Published: 2019-11-23
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geology, Geotechnical Engineering, Mining Engineering, Physical Sciences and Mathematics
Electropulse treatments employ a series of high-voltage discharges to break rock into small fragments. As these methods are particularly suited to fracturing hard brittle rocks, electropulse treatments can serve to enhance or substitute for more traditional mechanical approaches to drilling and processing of these materials. Nevertheless, while these treatments have the potential to improve [...]
Dynamic modelling of overprinted impermeable fault gouges and surrounding damage zones as lower dimensional interfaces
Published: 2019-11-14
Subjects: Chemical Engineering, Civil and Environmental Engineering, Computational Engineering, Engineering, Petroleum Engineering
In the modelling of subsurface fluid flow, faults are dominant features since they can act as fluid pathways or barriers. Special emphasis is therefore placed in representing them in a numerically efficient manner and the use of lower dimensional domains has become prevalent to simulate higher permeability features like fractures. Such features, however, only represent some of the components of [...]
Three-scale multiphysics finite element framework (FE3) modelling fault reactivation
Published: 2019-11-11
Subjects: Chemical Engineering, Computational Engineering, Engineering, Petroleum Engineering
Fluid injection or production in petroleum reservoirs affects the reservoir stresses such that it can even sometime reactivate dormant faults in the vicinity. In the particular case of deep car- bonate reservoirs, faults can also be chemically active; chemical dissolution of the fault core can transform an otherwise impermeable barrier to a flow channel. Due to the scale separation of the fault [...]
A note on the instability and pattern formation of shrinkage cracks in viscoplastic soils
Published: 2019-11-08
Subjects: Civil and Environmental Engineering, Engineering, Materials Science and Engineering
In this note we present a theoretical study on the conditions for the onset of cracks, as well as the corresponding pattern formation, in saturated viscoplastic soils under isotropic loading (extension). The type of stress applied is left unspecified, to cover a variety of loadings including shrinkage due to dessication, isotropic thermal expansion, mechanical loading and so forth. By treating [...]
Over 1000 rivers accountable for 80% of global riverine plastic emissions into the ocean
Published: 2019-10-24
Subjects: Civil and Environmental Engineering, Engineering, Environmental Engineering
Plastic waste increasingly accumulates in the marine environment, but data on the distribution and quantification of riverine sources, required for development of effective mitigation, are limited. Our new model approach includes geographical distributed data on plastic waste, landuse, wind, precipitation and rivers and calculates the probability for plastic waste to reach a river and [...]