Preprints
Filtering by Subject: Engineering
Phosphorus Retention in Lakes: A Critical Reassessment of Hypotheses and Static Models
Published: 2021-06-24
Subjects: Engineering, Environmental Engineering, Hydraulic Engineering, Hydrology, Water Resource Management
Various hypotheses and models for phosphorus (P) retention in lakes are reviewed and 39 predictive models are assessed in three categories, namely mechanistic, semi-mechanistic, and strictly-empirical models. A large database consisting of 738 data points is gathered for the analyses. Assessing four pairs of competing hypotheses used in mechanistic models, we found that (i) simulating lakes as [...]
Impact of injection rate ramp-up on nucleation and arrest of dynamic fault slip
Published: 2021-06-17
Subjects: Engineering
Fluid injection into underground formations reactivates preexisting geological discontinuities such as faults or fractures. In this work, we investigate the impact of injection rate ramp-up present in many standard injection protocols on the nucleation and potential arrest of dynamic slip along a planar pressurized fault. We assume a linear increasing function of injection rate with time, up to a [...]
Mapping carbon stocks in Central and South America with SMAP vegetation optical depth
Published: 2021-06-12
Subjects: Engineering, Life Sciences
Mapping carbon stocks in the tropics is essential for climate change mitigation. Passive microwave remote sensing allows estimating carbon from deep canopy layers through the Vegetation Optical Depth (VOD) parameter. Although their spatial resolution is coarser than that of optical vegetation indices or airborne Lidar data, microwaves present a higher penetration capacity at low frequencies [...]
European carbon storage resource requirements of climate change mitigation targets
Published: 2021-05-28
Subjects: Engineering, Physical Sciences and Mathematics
As a part of climate change mitigation plans in Europe, CO2 storage scenarios have been reported for the United Kingdom and the European Union with injection rates reaching 75 – 330 MtCO2 yr-1 by 2050. However, these plans are not constrained by geological properties or growth rates with precedent in the hydrocarbon industry. We use logistic models to identify growth trajectories and the [...]
Flood Markup Language – A Standards-based Exchange Language for Flood Risk Communication
Published: 2021-05-28
Subjects: Engineering
Flooding is one of the most common natural disasters. There are extensive amounts of studies on understanding and predicting flooding to support preparedness and response. It is critical to share and communicate flood forecasting and modeling datasets generated by different systems and organizations. Most of the organizations share flood risk data for operational purposes with limited metadata [...]
Non-stationary analysis of rogue wave probability over a shoal
Published: 2021-05-27
Subjects: Engineering, Physical Sciences and Mathematics
Non-equilibrium evolution of wave fields, as occurring over sudden bathymetry variations, can produce rogue seas with anomalous wave statistics. We handle this process by modifying the Rayleigh distribution through the energetics of second-order theory and a weakly non-stationarity reformulation of the Khintchine theorem. The probability model in unsteady conditions is then probed against [...]
Uncertainty analysis in machine learning for lithofacies classification and porosity prediction
Published: 2021-05-27
Subjects: Engineering, Physical Sciences and Mathematics
Recently, machine learning has been widely and successfully used by geoscientists to solve typical inverse problems. However, the uncertainty related to the learned model is not properly analysed, and sometimes a simple activation function is applied to provide posterior probability. To address this problem, variance of machine learning models is calculated that can provide additional information [...]
ANALYSIS OF OWNER DRIVEN APPROACH OF HOUSING RECONSTRUCTION AFTER GORKHA EARTHQUAKE 2015: A CASE STUDY OF DHUNIBESHI MUNICIPALITY, DHADING
Published: 2021-05-26
Subjects: Engineering
A 7.6 magnitude earthquake occurred in Gorkha district of Nepal leading more than 9,000 estimated casualties, approximately 23,000 injuries and damages on more than half a million structures. For leading and managing the earthquake recovery and reconstruction in Nepal, a legally mandated agency named National Reconstruction Authority (NRA) was established in December 2015 which facilitate and [...]
Automated mineralogy as a novel approach for the compositional and textural characterization of spent lithium-ion batteries
Published: 2021-05-21
Subjects: Engineering
Mechanical recycling processes aim to separate particles based on their physical properties, such as size, shape and density, and physico-chemical surface properties, such as wettability. Secondary materials, including electronic waste, are highly complex and heterogeneous, which complicates recycling processes. In order to improve recycling efficiency, characterization of both recycling process [...]
Determination of the spatial distribution of wetting in the pore networks of rocks
Published: 2021-05-17
Subjects: Engineering, Physical Sciences and Mathematics
The macroscopic movement of subsurface fluids involved in CO2 storage, groundwater, and petroleum engineering applications is controlled by interfacial forces in the pores of rocks, micrometre to millimetre in length scale. Recent advances in physics based models of these systems has arisen from approaches simulating flow through a digital representation of the complex pore structure. However, [...]
A damage model for the frictional shear failure of brittle materials in compression
Published: 2021-05-13
Subjects: Applied Mathematics, Computational Engineering, Earth Sciences, Engineering, Geology, Materials Science and Engineering, Physical Sciences and Mathematics
Damage models have been successfully employed for many decades in the modelling of tensile failure, where the crack surfaces separate as a crack grows. The advantage of this approach is that crack trajectories can be computed simply and efficiently on a fixed finite element mesh without explicit tracking. The development of damage models for shear failure in compression, where the crack faces [...]
Hydroclimatic Analysis of Rising Water Levels in the Great Rift Valley Lakes of Kenya
Published: 2021-05-05
Subjects: Engineering, Physical Sciences and Mathematics
Study Region The Great Rift Valley lakes of Kenya have recently experienced significant increases in their water levels, negatively impacting the local communities. This has provoked renewed concerns about the causations, with various geological, anthropogenic and hydro-climatic influences hypothesized as potential causes of the water level rises. Study Focus This study analyses and documents [...]
CO2 capture by pumping surface acidity to the deep ocean
Published: 2021-04-30
Subjects: Chemical Engineering, Climate, Engineering, Environmental Engineering, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The majority of IPCC scenarios call for active CO2 removal (CDR) to remain below 2oC of warm- ing. On geological timescales, ocean uptake regulates atmospheric CO2 concentration, with two homeostats driving CO2 uptake: dissolution of deep ocean calcite deposits and terrestrial weathering of silicate rocks, acting on 1ka to 100ka timescales, respectively. Many current ocean-based CDR proposals [...]
FROM THE PAST TO THE FUTURE: SPATIO-TEMPORAL DYNAMICS OF WATER-BALANCE IN A RAPIDLY URBANIZING KATHMANDU VALLEY WATERSHED OF NEPAL
Published: 2021-04-23
Subjects: Civil and Environmental Engineering, Engineering
The resources of the earth are under immense pressure due to the multiple anthropogenic influences. The land resources which largely attribute to the quality as well as quantity of the water, is facing extreme stress due to the rapid urbanization resulting from population growth as well as socio-economic development. It is imperative that the response of hydrological processes to the change in [...]
Decadal Evaluation of the AIRPACT Regional Air Quality Forecast System in the Pacific Northwest from 2009-2018
Published: 2021-04-21
Subjects: Engineering, Physical Sciences and Mathematics
The Air Indicator Report for Public Awareness and Community Tracking (AIRPACT) is a comprehensive, automated air quality forecast system that provides 48-hr in-advance air quality over the Pacific Northwest region (http://lar.wsu.edu/airpact/). Since 2001, the AIRPACT forecasting system has been successfully operated by Washington State University, with the financial support from the Northwest [...]