Preprints
Filtering by Subject: Civil and Environmental Engineering
Laboratory experiments and grain based discrete element numerical simulations investigating the thermo-mechanical behaviour of sandstone
Published: 2020-05-30
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geotechnical Engineering, Physical Sciences and Mathematics
Thermo-mechanical loading can occur in numerous engineering geological environments, from both natural and anthropogenic sources. Different minerals and micro-defects in rock cause heterogeneity at a grain scale, affecting the mechanical and thermal properties of the material. Changes in strength and stiffness can occur from exposure to elevated temperatures, with the accumulation of localised [...]
Evaluating single and multi-date Landsat classifications of land-cover in a seasonally dry tropical forest
Published: 2020-05-29
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Engineering, Environmental Monitoring, Environmental Sciences, Natural Resources and Conservation, Natural Resources Management and Policy, Other Civil and Environmental Engineering, Other Environmental Sciences, Physical Sciences and Mathematics
Accurate information on the land cover is crucial for efficient monitoring and development of environmental studies in the Brazilian Caatinga forest. It is the largest tropical seasonal forest in South America, presenting high biodiversity and is under intense anthropogenic disturbance. Caatingas land cover is heterogeneous, and rainfall is its primary phenological regulator, presenting mainly [...]
Predictive modelling of envelope flood extents using geomorphic and climatic-hydrologic catchment characteristics
Published: 2020-05-26
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Hydraulic Engineering, Hydrology, Physical Sciences and Mathematics
A topographic index (flood descriptor) that combines the scaling of bankfull depth with morphology was shown to describe the tendency of an area to be flooded. However, this approach depends on the quality and availability of flood maps and assumes that outcomes can be directly extrapolated and downscaled. This work attempts to relax these problems and answer two questions: 1) Can functional [...]
UNSEEN trends: Detecting decadal changes in 100-year precipitation extremes
Published: 2020-05-26
Subjects: Atmospheric Sciences, Civil and Environmental Engineering, Climate, Earth Sciences, Engineering, Environmental Sciences, Hydrology, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Sample sizes of observed climate extremes are typically too small to reliably constrain non-stationary behaviour. To facilitate detection of non-stationarities in 100-year precipitation values over a short period of 35 years (1981-2015), we apply the UNprecedented Simulated Extreme ENsemble (UNSEEN) approach, by pooling ensemble members and lead times from the ECMWF seasonal prediction system [...]
60 YEARS OF AIRBORNE AFMAG METHOD EVOLUTION
Published: 2020-05-25
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Geotechnical Engineering, Physical Sciences and Mathematics
Development and following commercial use of the airborne electromagnetic method based on natural fields in the audio-frequency band (AFMAG) started in late 50s of the last century. After several decades of the development downtime, limitations inherent to the method were resolved in 80s by adapting the tensor analysis, remote reference noise bias removal techniques and computation of the tippers. [...]
On the thermo-poro-mechanics of chemically active faults
Published: 2020-05-21
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Geotechnical Engineering, Physical Sciences and Mathematics
Shear zones in outcrops and core drillings on active faults commonly reveal two scales of localization, with centimeter to tens of meters thick deformation zones embedding much narrower zones of mm- to cm-scale. The narrow zones are often attributed to some form of fast instability such as earthquakes or slow slip events. Surprisingly, the double localisation phenomenon seem to be independent of [...]
Using Bayesian Hierarchical Modelling to capture cyanobacteria dynamics in Northern European lakes
Published: 2020-05-21
Subjects: Civil and Environmental Engineering, Engineering, Environmental Engineering
Cyanobacteria blooms in lakes and reservoirs currently threaten water security and affect the ecosystem services provided by these freshwater ecosystems, such as drinking water and recreational use. Climate change is expected to further exacerbate the situation in the future because of higher temperatures, extended droughts and nutrient enrichment, due to urbanisation and intensified agriculture. [...]
Probabilistic soil moisture dynamics of water- and energy-limited ecosystems
Published: 2020-05-18
Subjects: Agriculture, Agronomy and Crop Sciences Life Sciences, Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Engineering, Environmental Sciences, Forest Sciences, Hydrology, Life Sciences, Physical Sciences and Mathematics, Plant Sciences, Statistical Models, Statistics and Probability
This paper presents an extension of the stochastic ecohydrological model for soil moisture dynamics at a point of Rodriguez-Iturbe et al. (1999) and Laio et al. (2001). In the original model, evapotranspiration is a function of soil moisture and vegetation parameters, so that the model is suitable for water-limited environments. Our extension introduces a dependence on maximum evapotranspiration [...]
Permeability hysteresis from micro-channels opening during dissolution/reprecipitation cycle
Published: 2020-05-12
Subjects: Civil and Environmental Engineering, Computational Engineering, Engineering, Hydraulic Engineering
Permeability is a critical parameter for geological resources characterisation. Its evolution with respect to porosity is particularly interesting and many research initiatives focus on deriving such relationships, to understand some hydraulic impacts of microstructure alteration. Permeability evolution from chemical reactions for instance can become complex as flow channels may open during rock [...]
Estimating Submicron Aerosol Mixing State at the Global Scale with Machine Learning and Earth System Modeling
Published: 2020-05-07
Subjects: Atmospheric Sciences, Civil and Environmental Engineering, Computational Engineering, Computer Sciences, Earth Sciences, Engineering, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
This study integrates machine learning and particle-resolved aerosol simulations to develop emulators that predict sub-micron aerosol mixing state indices from the Earth System Model (ESM) simulations. The emulators predict aerosol mixing state using only ESM bulk aerosol species concentrations, which do not by themselves carry mixing state information. Here we used PartMC as the [...]
Evaluating Controller Performance and Placement on System-level Urban Flooding Reduction and Water Quality Improvement
Published: 2020-05-07
Subjects: Civil and Environmental Engineering, Civil Engineering, Engineering, Environmental Engineering
Increases in urbanization and climate change are forcing urban drainage engineers to more effectively leverage stormwater storage facilities to minimize flooding and water quality impacts. This process becomes increasingly challenging due to the operations of storage coordination across the system-level watershed. This study presents a system-level real-time control simulation for assessing [...]
Permeability computation of high resolution µCTscan with an unfitted boundary method to improve accuracy
Published: 2020-05-07
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Hydraulic Engineering, Hydrology, Physical Sciences and Mathematics
Flow simulations on porous media, reconstructed from Micro-Computerised Tomography (μCT)-scans, is becoming a common tool to compute the permeability of rocks. In order for the value of this homogenised hydraulic property to be representative of the rock at a continuum scale, the sample considered needs to be at least as large as the Representative Elementary Volume. More- over, the numerical [...]
A Data-driven Improved Fuzzy Logic Control Optimization-simulation Tool for Reducing Flooding Volume at Downstream Urban Drainage Systems
Published: 2020-04-30
Subjects: Civil and Environmental Engineering, Civil Engineering, Engineering, Environmental Engineering
The uncertainty of climate change and urbanization imposed additional stress for urban drainage systems (UDSs) by intensifying rainfall frequency and magnifying peak runoff rate. UDSs are among the stormwater infrastructures that can be controlled in real-time for mitigating downstream urban flooding. In this paper, a data-driven improved real-time control optimization-simulation tool called [...]
A Performance Comparison of Unsupervised Machine Learning Algorithms for Clustering Water Depth Datasets at Urban Drainage Systems
Published: 2020-04-30
Subjects: Civil and Environmental Engineering, Civil Engineering, Engineering, Environmental Engineering
As sensor measurements emerge in urban water systems, data-driven unsupervised machine learning algorithms have been drawn tremendous interest in infrastructure monitoring, flow prediction, and pollutant warning recently. However, most of them are applied in water distribution systems, and few studies consider using unsupervised clustering analysis to group the time-series hydraulic-hydrologic [...]
Protecting rivers by integrating supply-wastewater infrastructure planning and coordinating operational decisions
Published: 2020-04-30
Subjects: Civil and Environmental Engineering, Engineering, Environmental Engineering
Placing water quality in rivers at the centre of water infrastructure planning and management is an important objective. In response there has been a range of whole system analyses. Few studies, however, consider both abstraction (water removed from rivers) and discharge (water returned) to inform the future planning of water systems. In this work we present a systems approach to analysing future [...]