Preprints
Filtering by Subject: Engineering
Spectral element modelling of seismic wave propagation in visco-elastoplastic media including excess-pore pressure development
Published: 2021-01-06
Subjects: Earth Sciences, Engineering, Geophysics and Seismology, Geotechnical Engineering
Numerical modelling of seismic wave propagation, considering soil nonlinearity, has become a major topic in seismic hazard studies when strong shaking is involved under particular soil conditions. Indeed, when strong ground motion propagates in saturated soils, pore pressure is another important parameter to take into account when successive phases of contractive and dilatant soil behaviour are [...]
Climate change induced effects or maldevelopment: small islands and conflicting attribution of root causes
Published: 2020-12-21
Subjects: Engineering, Social and Behavioral Sciences
Adapting to sea level rise, climate change, and associated effects is especially challenging in sensitive small-island environments where false adaptation can lead to adverse impacts on natural and societal dynamics. Framing and interest play a decisive role for the successful implementation of any adaptation measures. An interdisciplinary perspective on the interaction of natural dynamics, [...]
Evidence-based conservation in a changing world: lessons from waterbird individual-based models
Published: 2020-12-16
Subjects: Engineering, Physical Sciences and Mathematics, Social and Behavioral Sciences
Drivers of environmental change are causing novel combinations of pressures on ecological systems. Prediction in ecology often uses understanding of past conditions to make predictions to the future, but such an approach can breakdown when future conditions have not previously been encountered. Individual-based models (IBMs) consider ecological systems as arising from the adaptive behaviour and [...]
Anatomy of Strike Slip Fault Tsunami-genesis
Published: 2020-12-13
Subjects: Earth Sciences, Engineering, Fluid Dynamics, Geophysics and Seismology, Physical Sciences and Mathematics, Physics
Tsunami generation from earthquake induced seafloor deformations has long been recognized as a major hazard to coastal areas. Strike-slip faulting has generally been believed as insufficient for triggering large tsunamis, except through the generation of submarine landslides. Herein, we demonstrate that ground motions due to strike-slip earthquakes can contribute to the emergence of large [...]
High-resolution downscaled CMIP5 projections dataset of essential surface climate variables over Europe coherent with ERA5-Land reanalyses for climate change impact assessments
Published: 2020-11-27
Subjects: Engineering, Life Sciences, Physical Sciences and Mathematics
A high-resolution climate projections dataset is obtained by statistically downscaling climate projections from the CMIP5 experiment using the ERA5-Land reanalyses from the Copernicus Climate Change service. The dataset is over Europe, has a spatial resolution of 0.10° x 0.10°, comprises 21 climate models and includes 5 surface daily variables: air temperature (mean, minimum, and maximum), [...]
High-resolution downscaled CMIP5 projections dataset of essential surface climate variables over the globe coherent with ERA5 reanalyses for climate change impact assessments
Published: 2020-11-27
Subjects: Engineering, Life Sciences, Physical Sciences and Mathematics
A high-resolution climate projections dataset is obtained by statistically downscaling climate projections from the CMIP5 experiment using the ERA5 reanalyses from the Copernicus Climate Change service. The dataset is global has a spatial resolution of 0.25°x 0.25°, comprises 21 climate models and includes 5 surface daily variables: air temperature (mean, minimum, and maximum), precipitation, and [...]
The development of intermittent multiphase fluid flow pathways through a porous rock
Published: 2020-11-18
Subjects: Engineering, Physical Sciences and Mathematics
Intermittent fluid flow has recently been identified as an important transport mode for subsurface multiphase flow systems such as CO2 storage and natural gas production. However, due to experimental limitations, it has not been possible to identify why intermittency occurs at subsurface conditions and what the implications are for upscaled flow properties such as relative permeability. We [...]
Improving mechanical behaviour of collapsible soils by grouting active clay nanoparticles
Published: 2020-10-27
Subjects: Engineering, Physical Sciences and Mathematics
The primary geotechnical concern of collapsible soils such as loess is their hydromechanical instability. During (re)wetting, metastable aggregates disintegrate leading soil to collapse under the applied load or self-weight. In situ chemical stabilisation, such as grouting, is a favoured option to improve the mechanical behaviour of soils; however, the low permeability of loess limits the [...]
Forecasting landslides by taking their temperature: Combining mathematical and experimental modeling with field data on the case of the El Forn landslide (Andorra)
Published: 2020-10-25
Subjects: Engineering
In this study we are suggesting a temperature-based modeling approach for deep-seated landslides, validated through combined field monitoring and experimental testing. The Silurian shales of the shear band of El Forn landslide (Andorra) have been characterized through thermal and rate controlled triaxial tests, thereby calibrating a mathematical model that is used to monitor the behavior of [...]
An Urban Planning Sustainability Framework: Systems Approach to Blue Green Urban Design
Published: 2020-10-23
Subjects: Engineering
The climate emergency and population growth are challenging water security and sustainable urban design in cities worldwide. Sustainable urban development is crucial to minimise pressures on the natural environment and on existing urban infrastructure systems, including water, energy, and land. These pressures are particularly evident in London, which is considered highly vulnerable to water [...]
Development of new Index based supervised algorithm for separation of Built-Up and River Sand pixels from Landsat7 imagery : Comparison of performance with SVM
Published: 2020-10-22
Subjects: Computational Engineering, Engineering, Environmental Engineering
While classifying “built-up” pixels from satel- lite imagery, both machine learning & index based algo- rithms often misclassify “river sand” pixels as “built-up” ones due to the similarity in their spectral profiles. With the help of the spectral reflectance information in BLUE & GREEN bands of Landsat satellite imagery, this study has introduced a new index BRSSI (Built-Up & River Sand [...]
Tuning sedimentation through surface charge and particle shape
Published: 2020-10-22
Subjects: Engineering, Physical Sciences and Mathematics
Mud forms the foundation of many coastal and tidal environments. Clay suspensions carried downstream from rivers encounter saline waters, which encourages aggregation and sedimentation by reducing electrostatic repulsion among particles. We perform experiments to examine the effects of surface charge on both the rate and style of sedimentation, using kaolinite particles as a model mud suspension [...]
An explanation to the Nusselt-Rayleigh discrepancy in naturally convected porous media
Published: 2020-10-22
Subjects: Engineering, Physical Sciences and Mathematics
We model hydrothermal convection using a partial differential equation formed by Darcy velocity and temperature - the velocity formulation. Using the Elder problem as a benchmark, we found that the velocity formulation is a valid model of hydrothermal convection. By performing simulations with Rayleigh numbers in the non-oscillatory regime, we show that multiple quasi-steady-state solutions can [...]
Structure-from-Motion on shallow reefs and beaches: potential and limitations of consumer-grade drones to reconstruct topography and bathymetry
Published: 2020-10-21
Subjects: Civil Engineering, Engineering, Environmental Engineering, Environmental Monitoring, Environmental Studies, Fluid Dynamics, Fresh Water Studies, Geographic Information Sciences, Hydraulic Engineering, Other Civil and Environmental Engineering, Other Environmental Sciences, Remote Sensing
Reconstructing the topography of shallow underwater environments using Structure-from-Motion – Multi View Stereo (SfM-MVS) techniques applied to aerial imagery from Unmanned Aerial Vehicles (UAVs) is a challenging problem, as it involves non-linear distortions caused by water refraction. This study presents an experiment with aerial photographs collected with a consumer-grade UAV on the [...]
River Planform Extraction From High-Resolution SAR Images Via Generalised Gamma Distribution Superpixel Classification
Published: 2020-10-21
Subjects: Computer Engineering, Electrical and Computer Engineering, Engineering, Geology, Geomorphology, Hydrology
The extraction of river planforms from remotely sensed satellite images is a task of crucial importance to many applications such as land planning, water resource monitoring or flood prediction. In this paper we present a novel framework for the extraction of rivers from Synthetic Aperture Radar (SAR) images, based on superpixel segmentation and subsequent classification. Superpixel segmentation [...]