Effect of soil consolidation on soil-lining interaction in tunnels

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.Includes bibliographical references (leaves 109-116).by Alexios Leonidas Liakos.S.M

Phosphorus plant removal from European agricultural land

AbstractPhosphorus (P) is an important nutrient for all plant growth and it has become a critical and often imbalanced element in modern agriculture. A proper crop fertilization is crucial for production, farmer profits, and also for ensuring sustainable agriculture. The European Commission has published the Farm to Fork (F2F) Strategy in May 2020, in which the reduction of the use of fertilizers by at least 20% is among one of the main objectives. Therefore, it is important to look for the optimal use of P in order to reduce its pollution effects but also ensure future agricultural production and food security. It is essential to estimate the P budget with the best available data at the highest possible spatial resolution. In this study, we focused on estimating the P removal from soils by crop harvest and removal of crop residues. Specifically, we attempted to estimate the P removal by taking into account the production area and productivity rates of 37 crops for 220 regions in the European Union (EU) and the UK. To estimate the P removal by crops, we included the P concentrations in plant tissues (%), the crop humidity rates, the crop residues production, and the removal rates of the crop residues. The total P removal was about 2.55 million tonnes (Mt) (± 0.23 Mt), with crop harvesting having the larger contribution (ca. 94%) compared to the crop residues removal. A Monte-Carlo analysis estimated a ± 9% uncertainty. In addition, we performed a projection of P removal from agricultural fields in 2030. By providing this picture, we aim to improve the current P balances in the EU and explore the feasibility of F2F objectives

EUSEDcollab: a network of data from European catchments to monitor net soil erosion by water

As a network of researchers we release an open-access database (EUSEDcollab) of water discharge and suspended sediment yield time series records collected in small to medium sized catchments in Europe. EUSEDcollab is compiled to overcome the scarcity of open-access data at relevant spatial scales for studies on runoff, soil loss by water erosion and sediment delivery. Multi-source measurement data from numerous researchers and institutions were harmonised into a common time series and metadata structure. Data reuse is facilitated through accompanying metadata descriptors providing background technical information for each monitoring station setup. Across ten European countries, EUSEDcollab covers over 1600 catchment years of data from 245 catchments at event (11 catchments), daily (22 catchments) and monthly (212 catchments) temporal resolution, and is unique in its focus on small to medium catchment drainage areas (median=43km2, min=0.04km2, max=817km2) with applicability for soil erosion research. We release this database with the aim of uniting people, knowledge and data through the European Union Soil Observatory (EUSO)

Challenges in the Geo-Processing of Big Soil Spatial Data

This study addressed a critical resource—soil—through the prism of processing big data at the continental scale. Rapid progress in technology and remote sensing has majorly improved data processing on extensive spatial and temporal scales. Here, the manuscript presents the results of a systematic effort to geo-process and analyze soil-relevant data. In addition, the main highlights include the difficulties associated with using data infrastructures, managing big geospatial data, decentralizing operations through remote access, mass processing, and automating the data-processing workflow using advanced programming languages. Challenges to this study included the reproducibility of the results, their presentation in a communicative way, and the harmonization of complex heterogeneous data in space and time based on high standards of accuracy. Accuracy was especially important as the results needed to be identical at all spatial scales (from point counts to aggregated countrywide data). The geospatial modeling of soil requires analysis at multiple spatial scales, from the pixel level, through multiple territorial units (national or regional), and river catchments, to the global scale. Advanced mapping methods (e.g., zonal statistics, map algebra, choropleth maps, and proportional symbols) were used to convey comprehensive and substantial information that would be of use to policymakers. More specifically, a variety of cartographic practices were employed, including vector and raster visualization and hexagon grid maps at the global or European scale and in several cartographic projections. The information was rendered in both grid format and as aggregated statistics per polygon (zonal statistics), combined with diagrams and an advanced graphical interface. The uncertainty was estimated and the results were validated in order to present the outputs in the most robust way. The study was also interdisciplinary in nature, requiring large-scale datasets to be integrated from different scientific domains, such as soil science, geography, hydrology, chemistry, climate change, and agriculture

Challenges in the Geo-Processing of Big Soil Spatial Data

This study addressed a critical resource—soil—through the prism of processing big data at the continental scale. Rapid progress in technology and remote sensing has majorly improved data processing on extensive spatial and temporal scales. Here, the manuscript presents the results of a systematic effort to geo-process and analyze soil-relevant data. In addition, the main highlights include the difficulties associated with using data infrastructures, managing big geospatial data, decentralizing operations through remote access, mass processing, and automating the data-processing workflow using advanced programming languages. Challenges to this study included the reproducibility of the results, their presentation in a communicative way, and the harmonization of complex heterogeneous data in space and time based on high standards of accuracy. Accuracy was especially important as the results needed to be identical at all spatial scales (from point counts to aggregated countrywide data). The geospatial modeling of soil requires analysis at multiple spatial scales, from the pixel level, through multiple territorial units (national or regional), and river catchments, to the global scale. Advanced mapping methods (e.g., zonal statistics, map algebra, choropleth maps, and proportional symbols) were used to convey comprehensive and substantial information that would be of use to policymakers. More specifically, a variety of cartographic practices were employed, including vector and raster visualization and hexagon grid maps at the global or European scale and in several cartographic projections. The information was rendered in both grid format and as aggregated statistics per polygon (zonal statistics), combined with diagrams and an advanced graphical interface. The uncertainty was estimated and the results were validated in order to present the outputs in the most robust way. The study was also interdisciplinary in nature, requiring large-scale datasets to be integrated from different scientific domains, such as soil science, geography, hydrology, chemistry, climate change, and agriculture

Urban sprawl models and monitoring with remote sensing of night time lights

The dissertation aims at monitoring and analyzing the urban activity of greek cities through the exploitation of a particular category of remote sensing data, the night time lights. It is observed that night lights significantly reflect urbanization levels and economic development and are strong correlated with economic variables such as GDP, population, construction activity and consumption electricity. The dissertation is supported by the main datasets of night lights (DMPS/OLS, snpp-VIIRS, ISS) to capture the greek urban reality. Nighttime lights datasets are available without having undergone pre-processing steps to remove factors affecting their quality and research results. Significant external factors are influencing data quality, such as lunar radiation. Technical features and limitations, such as the overglow and saturation of DSMP/OLS data, continue to concern the scientific community. In the framework of the dissertation new methods will be proposed to correct lunar radiation from snpp-VIIRS datasets. An attempt will be made to improve DMSP/OLS data with the support of SAR data. In addition, datasets from the Luojia 1-01 satellite and images from the ISS, through their separate features, can help assessment accuracy of existing and established data (DMPS/OLS, snpp-VIIRS). The aim of the dissertation is to take advantage of the night light data to record the seasonality of urban areas in Greece, to simulate the urban sprawl that will take place in the future, to predict the intensity of urban activity, to estimate in a detailed spatial and temporal scale economic variables such as GDP. Night time lights will be used to evaluate the consequences of extraordinary conditions in urban activity, to assess burden on light pollution and to describe the commuting patterns in modern greek cities. The results arising from the dissertation are remarkable. Innovative methods improve data and analysis, prediction and interpretation of urban phenomena. The use of night lights is an important tool in the hands of the researcher but it requires deep awareness of technical limitations and of exogenous factors affecting their capabilities.Η διατριβή στοχεύει στην παρακολούθηση και ανάλυση της λειτουργίας των ελληνικών αστικών περιοχών μέσω της εκμετάλλευσης μιας ιδιαίτερης κατηγορίας δεδομένων τηλεπισκόπησης, των νυκτερινών φώτων. Τα νυκτερινά φώτα έχει παρατηρηθεί ότι αντικατοπτρίζουν σε σημαντικό βαθμό τα επίπεδα αστικής και οικονομικής ανάπτυξης και είναι άρρηκτα συνδεδεμένα με οικονομικά μεγέθη όπως το ΑΕΠ, ο πληθυσμός, η οικοδομική δραστηριότητα και η κατανάλωση του ηλεκτρικού ρεύματος. Η διεξαγωγή της διατριβής υποστηρίζεται από τα κυριότερα σύνολα δεδομένων νυκτερινών φώτων (DMPS/OLS, snpp-VIIRS, ISS) για την αποτύπωση της ελληνικής αστικής πραγματικότητας. Τα δεδομένα νυχτερινών φώτων διατίθενται χωρίς να έχουν υποστεί την απαραίτητη προεπεξεργασία για την αφαίρεση παραγόντων που επηρεάζουν την ποιότητά τους και τα αποτελέσματα της έρευνας. Σημαντικοί εξωγενείς παράγοντες επιρροής της ποιότητας των δεδομένων, όπως η σεληνιακή ακτινοβολία, δεν έχουν αφαιρεθεί. Τεχνικά χαρακτηριστικά και περιορισμοί όπως η υπερλάμψη και ο κορεσμός των δεδομένων DSMP/OLS συνεχίζουν να απασχολούν την επιστημονική κοινότητα. Στα πλαίσια της διατριβής προτείνονται μεθόδοι για την διόρθωση της σεληνιακής ακτινοβολίας από τα δεδομένα snpp-VIIRS και επιχειρείται η βελτίωση των δεδομένων DMSP/OLS με την συνδρομή δεδομένων SAR. Στόχος της διατριβής είναι να εκμεταλλευτεί τα δεδομένα νυχτερινών φώτων για να καταγράψει την εποχικότητα των αστικών περιοχών στον Ελλαδικό χώρο, να προσομοιώσει την αστική διάχυση που θα λάβει χώρα στο μέλλον, να προβλέψει την ένταση της αστικής δραστηριότητας, να εκτιμήσει σε λεπτομερή χωρική και χρονική κλίμακα οικονομικές μεταβλητές όπως το ΑΕΠ. Τα νυχτερινά φώτα χρησιμοποιούνται για να αποτιμηθούν οι συνέπειες έκτακτων συνθηκών στην αστική δραστηριότητα, για να εκτιμηθεί η επιβάρυνση από την φωτορύπανση και για να περιγραφούν τα πρότυπα μετακίνησης στις σύγχρονες ελληνικές πόλεις. Από τα αποτελέσματα προκύπτουν αξιόλογες και καινοτόμες μέθοδοι για την βελτίωση των δεδομένων και την ανάλυση, πρόβλεψη και ερμηνεία των αστικών φαινομένων. Η χρήση νυχτερινών φώτων αποτελεί ένα σημαντικό εργαλείο στα χέρια του ερευνητή αλλά απαιτεί βαθειά επίγνωση των τεχνικών περιορισμών και των εξωγενών παράγοντων που επηρεάζουν τις δυνατότητές τους

Mercury in European topsoils: Anthropogenic sources, stocks and fluxes

Mercury (Hg) is one of the most dangerous pollutants worldwide. In the European Union (EU), we recently estimated the Hg distribution in topsoil using 21,591 samples and a series of geo-physical inputs. In this manuscript, we investigate the impact of mining activities, chrol-alkali industries and other diffuse pollution sources as primary anthropogenic sources of Hg hotspots in the EU. Based on Hg measured soil samples, we modelled the Hg pool in EU topsoils, which totals about 44.8 Gg, with an average density of 103 g ha; -1; . As a following step, we coupled the estimated Hg stocks in topsoil with the pan-European assessment of soil loss due to water erosion and sediment distribution. In the European Union and UK, we estimated that about 43 Mg Hg yr; -1; are displaced by water erosion and c. a. 6 Mg Hg yr; -1; are transferred with sediments to river basins and eventually released to coastal Oceans. The Mediterranean Sea receives almost half (2.94 Mg yr; -1; ) of the Hg fluxes to coastal oceans and it records the highest quantity of Hg sediments. This is the result of elevated soil Hg concentration and high erosion rates in the catchments draining into the Mediterranean Sea. This work contributes to new knowledge in support of the policy development in the EU on the Zero Pollution Action Plan and the Sustainable Development Goal (SDGs) 3.9 and 14.1, which both have as an objective to reduce soil pollution by 2030

An in-depth statistical analysis of the rainstorms erosivity in Europe

Heavy rainstorms play a central role in the water-driving soil erosion processes. An in-depth knowledge about temporal and spatial erosivity of rainfall events is required to gain a better understanding of soil erosion processes and optimize soil protection measures efficiency. In this study, the spatiotemporal distribution of more than 300,000 erosive events measured at 1181 locations, part of the Rainfall Erosivity Database at European Scale (REDES) database, is studied to shed some new light on the rainfall erosivity in Europe. Rainfall erosive events are statistically investigated through the Lorenz curve and derived coefficients such as the Gini coefficient (G). Additionally, seasonal characteristics of the most and the less erosive events are compared to investigate seasonal characteristics of rainstorms across Europe. The G shows largest values of inequality of the inter-annual temporal distribution of the rainfall erosive events in the Alpine region, mostly due to the large number of rainfall events with smaller rainfall erosivity. While for other parts of Europe, the inequality described by the G is mostly due to a small number of high erosive events. The G slightly decreases from south to north while no clear regional patterns can be detected. Additionally, in Europe, on average 11% (ranging from 1 to 24%) of all erosive events contribute to form 50% of the total rainfall erosivity. Furthermore, higher erosive rainfall events tend to occur later in the year compared to less erosive events that take place earlier. To our knowledge, this study is the first one addressing event scale rainfall erosivity distribution using more than 300,000 rainfall erosivity events and covering almost a whole continent. Scientifically our findings represent a major step towards large-scale process-based erosion modelling while, practically, they provide new elements that can support national and local soil erosion monitoring program

Global rainfall erosivity projections for 2050 and 2070

The erosive force of rainfall (rainfall erosivity) is a major driver of soil, nutrient losses worldwide and an important input for soil erosion assessments models. Here, we present a comprehensive set of future erosivity projections at a 30 arc-second (~1km2) spatial scale using 19 downscaled General Circulation Models (GCMs) simulating three Representative Concentration Pathways (RCPs) for the periods 2041-2060 and 2061-2080. The future rainfall erosivity projections were obtained based on a Gaussian Process Regression (GPR) approach relating rainfall depth to rainfall erosivity through a series of (bio)climatic covariates. Compared to the 2010 Global Rainfall erosivity baseline, we estimate a potential average increase in global rainfall erosivity between 26.2-28.8% for 2050 and 27-34.3% for 2070. Therefore, climate change and the consequential increase in rainfall erosivity is the main driver of the projected +30-66% increase in soil erosion rates by 2070

The significance of right-sided chest leads in exercise testing for the detection of right ventricular dysfunction post myocardial infarction of the inferior wall

Background: The incorporation of right-sided chest leads (V3R-V5R) into the standard exercise testing has been reported to improve its diagnostic accuracy. The purpose of this study was to evaluate the ability of exercise testing in detecting right ventricular (RV) dysfunction post myocardial infarction (MI) of the inferior wall, using additional V3R-V5R leads. Methods: We studied 133 patients (59 +/- 5 years, 81 males) with a history of inferior MI due to right coronary artery obstruction (affirmed with coronary angiography). All patients underwent an echocardiographic assessment of RV function 4 weeks after discharge and an exercise treadmill test in order to detect possible RV dysfunction. Recordings during exercise were obtained with the standard 12 leads plus V3R-V5R. Results: From 133 patients, 97 (group A) presented with normal right ventricle according to the echocardiographic study while the rest 36 patients (group B) presented with RV dysfunction. Maximal exercise-induced ST-segment deviation (in mm) was similar in the standard 12 leads for the 2 groups (2.1 +/- 0.4 vs 1.8 +/- 0.3, p=NS) while in V3R-V5R it was greater in group B (0.7 +/- 0.3 vs 1.4 +/- 0.4, p<0.05). Sensitivity, positive prognostic value, negative prognostic value and accuracy of exercise testing in detecting RV dysfunction were all improved using V3R-V5R (78 vs 47%, 39 vs 29%, 87 vs 75%, 62 vs 55% respectively, p<0.05 for all) while specificity was not deteriorated (56 vs 58%, p=NS). Conclusions: The addition of right-sided chest leads (V3R-V5R) improves the diagnostic ability of standard exercise testing in detecting and especially in excluding RV dysfunction post inferior MI. (C) 2009 Elsevier Ireland Ltd. All rights reserved