Bentonite as an industrial mineral and comparison between Greek and Northern American bentonite

Σκοπός της συγκεκριμένης πτυχιακής εργασίας είναι η σύγκριση δύο διαφορετικών τύπων μπεντονίτη, ενός από την Κίμωλο, Ελλάδα και ενός από το Γουαϊόμινγκ, ΗΠΑ, με στόχο την εύρεση ομοιοτήτων και διαφορών. Ο μπεντονίτης της Κιμώλου εμφανίζεται κυρίως λευκός ή σε αποχρώσεις πολύ απαλού γκρι, ενώ αντιθέτως του Γουαϊόμινγκ, σκούρο γκρι. Επιπλέον, ο μπεντονίτης της Κιμώλου είναι ασβεστομαγνησιούχος, ενώ του Γουαϊόμινγκ, νατρούχος. Και οι δύο μπεντονίτες παρουσιάζουν τον ίδιο γενετικό τύπο, που χαρακτηρίζεται από την εξαλλοίωση της ηφαιστειακής τέφρας, λόγω θέρμανσης του νερού των ρηχών λεκανών σε αλκαλικά θαλάσσια ή λιμναία περιβάλλοντα. Όμως αυτό το γεγονός έλαβε χώρα στο Γουαϊόμινγκ στο Κρητιδικό (Κατώτερο Άλβιο – Ανώτερο Κενομάνιο), ενώ στην Κίμωλο στο Κατώτερο Πλειστόκαινο. Στο Γουαϊόμινγκ, τα στρώματα μπεντονίτη εμφανίζουν την ίδια κυκλική ακολουθία ιζηματογένεσης, η οποία, από κάτω προς τα πάνω, περιλαμβάνει σχιστόλιθο, γαιάνθρακα, μπεντονίτη και τελικά σχιστόλιθο που μεταπίπτει σε ψαμμίτη και κροκαλοπαγές. (Slaughter and Earley, 1965) Ενώ στην Κίμωλο, ο μπεντονίτης σχηματίζεται από την δομικά ελεγχόμενη υδροθερμική εξαλλοίωση του Ιγνιμβρίτη Πρασσών. Στα πλαίσια της έρευνας για τον χαρακτηρισμό του μπεντονίτη της Κιμώλου και του Γουαϊόμινγκ ήταν απαραίτητες οι εξής αναλύσεις, Φασματοσκοπία FT-IR, Ατομική απορρόφηση, Xρωματογραφία ιοντοανταλλαγής, Θερμική ανάλυση, απώλεια πύρωσης (LOI), φθορισμός ακτινών Χ (XRF), Περίθλαση ακτινών Χ (XRD) – Rietveld, Δοκιμή ιοντοανταλλακτικής ικανότητας με Κυανό του Μεθυλενίου και ποσοστό Άνθρακα - θείου.The aim of the study is to compare two different bentonite types, one from Kimolos, Greece and one from Wyoming, USA, in order to determine their similarities or differences. Kimolian bentonite appears to be usually white or very light gray than Wyoming one, which is dark gray. Furthermore, Kimolian is a Ca/Mg bentonite and Wyoming one is a natural Na bentonite. Βoth of them have the same genetic type which is the alteration of volcanic ash by heating the water of shallow basins in alkaline marine or lacustrine environments, but it took place in Cretaceous times (Late Albian to early Cenomanian), in Wyoming and in Lower Pleistocene, in Kimolos. In Wyoming the bentonite beds occur in the same cyclic sedimentary sequence which, from bottom to top, comprises shale, coal, bentonite, and finally shale grading to sandstone and conglomerate (Slaughter and Earley, 1965). While in Kimolos, bentonite is formed from the unwelded Prassa ignimbrite, the alteration (hydrothermal activity) being structurally controlled. In the framework of the research for the characterization of the bentonite deposit of Kimolos and Wyoming, FT-IR, Atomic Absorption, Ion chromatography, Thermal analysis, Loss of Ignition, X-ray fluorescence (XRF), X-ray diffractometer (XRD) – Rietveld, Methylene Blue Test and Percentage of Carbon and Sulfur presence analysis were executed for specific samples

Επισκόπηση μεθόδων ανάλυσης δεδομένων με χρήση Σημασιολογικών Στοιχείων και Γράφων Γνώσης

Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Τεχνο-Οικονομικά Συστήματα (ΜΒΑ)

On the use of radio environment maps for interference management in heterogeneous networks

©2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This article addresses the use of REMs to support interference management optimization in heterogeneous networks composed of cells of different sizes and including both cellular and non-cellular (e.g. WiFi) technologies. After presenting a general architecture for including REM databases in different network entities, the article analyzes the achievable benefits in relation to specific interference management techniques, including a discussion on practical considerations such as information exchange requirements, REM ownership, and security aspects. Finally, several research directions derived from the proposed framework are identified.Peer ReviewedPostprint (author's final draft

Post-intervention Status in Patients With Refractory Myasthenia Gravis Treated With Eculizumab During REGAIN and Its Open-Label Extension

OBJECTIVE: To evaluate whether eculizumab helps patients with anti-acetylcholine receptor-positive (AChR+) refractory generalized myasthenia gravis (gMG) achieve the Myasthenia Gravis Foundation of America (MGFA) post-intervention status of minimal manifestations (MM), we assessed patients' status throughout REGAIN (Safety and Efficacy of Eculizumab in AChR+ Refractory Generalized Myasthenia Gravis) and its open-label extension. METHODS: Patients who completed the REGAIN randomized controlled trial and continued into the open-label extension were included in this tertiary endpoint analysis. Patients were assessed for the MGFA post-intervention status of improved, unchanged, worse, MM, and pharmacologic remission at defined time points during REGAIN and through week 130 of the open-label study. RESULTS: A total of 117 patients completed REGAIN and continued into the open-label study (eculizumab/eculizumab: 56; placebo/eculizumab: 61). At week 26 of REGAIN, more eculizumab-treated patients than placebo-treated patients achieved a status of improved (60.7% vs 41.7%) or MM (25.0% vs 13.3%; common OR: 2.3; 95% CI: 1.1-4.5). After 130 weeks of eculizumab treatment, 88.0% of patients achieved improved status and 57.3% of patients achieved MM status. The safety profile of eculizumab was consistent with its known profile and no new safety signals were detected. CONCLUSION: Eculizumab led to rapid and sustained achievement of MM in patients with AChR+ refractory gMG. These findings support the use of eculizumab in this previously difficult-to-treat patient population. CLINICALTRIALSGOV IDENTIFIER: REGAIN, NCT01997229; REGAIN open-label extension, NCT02301624. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that, after 26 weeks of eculizumab treatment, 25.0% of adults with AChR+ refractory gMG achieved MM, compared with 13.3% who received placebo

Minimal Symptom Expression' in Patients With Acetylcholine Receptor Antibody-Positive Refractory Generalized Myasthenia Gravis Treated With Eculizumab

The efficacy and tolerability of eculizumab were assessed in REGAIN, a 26-week, phase 3, randomized, double-blind, placebo-controlled study in anti-acetylcholine receptor antibody-positive (AChR+) refractory generalized myasthenia gravis (gMG), and its open-label extension

Nitrogen and Phosphorus Loads in Greek Rivers: Implications for Management in Compliance with the Water Framework Directive

Reduction of nutrient loadings is often prioritized among other management measures for improving the water quality of freshwaters within the catchment. However, urban point sources and agriculture still thrive as the main drivers of nitrogen and phosphorus pollution in European rivers. With this article we present a nationwide assessment of nitrogen and phosphorus loads that 18 large rivers in Greece receive with the purpose to assess variability among seasons, catchments, and river types and distinguish relationships between loads and land uses of the catchment. We employed an extensive dataset of 636 field measurements of nutrient concentrations and river discharges to calculate nitrogen and phosphorus loads. Descriptive statistics and a cluster analysis were conducted to identify commonalties and differences among catchments and seasons. In addition a network analysis was conducted and its modularity feature was used to detect commonalities among rivers and sampling sites with regard to their nutrient loads. A correlation analysis was used to identify major possible connections between types of land uses and nutrient loads. The results indicated that the rivers Alfeios, Strymonas, and Aliakmonas receive the highest inorganic nitrogen loads while the highest inorganic phosphorus loads were calculated for the rivers Strymonas, Aliakmonas, and Axios. Concerning the temporal variation of loads, inorganic nitrogen presented a peak on March and gradually declined until October when the dry period typically ends for most regions of Greece. Inorganic phosphorus loads had the highest average value in August and the lowest in October. Thus, our findings confirmed the presence of a typical seasonal variation in nitrogen loads that follows the seasonality in hydrology where high surface runoff during the wet months contribute to higher river discharges and higher nitrogen loads from the catchment. On the contrary, high phosphorus loads persisted during dry months that could be attributed to a dilution effect. Furthermore, the results imply a clear connection between agriculture and both nitrogen and phosphorus. Overall, this work presents extensive information on the nitrogen and phosphorus loads that major rivers in Greece receive that can largely aid water managers to adapt and revise basin management plans in accordance with agricultural management (e.g., which months farmers should reduce the use of fertilizers) with the purpose of meeting the environmental targets defined by the Water Framework Directive (WFD)

The role of geosciences in geothermal resources and CCS

Summarization: Geothermal resources and Carbon Capture Sequestration (CCS) are upcoming and innovative technologies, while also being environmentally friendly. Geothermal resources rely on geothermal energy, which is Earth's natural internal heat. Geothermal energy is clean, renewable, sustainable, and available 24/7.This heat is used for many purposes, such as power generation and district heating/cooling, instead of fossil fuels. As a result, carbon footprint is lower, and the emission of greenhouse gases is preserved at low levels. CCS, on the other hand, prevents CO2 from releasing into the atmosphere and mitigate global warming, which is responsible for climate change. The role of geosciences, in Geothermal Resources and Carbon Capture Sequestration, is significant, with Geology having the main role. In Geothermal resources, geology is responsible for their existence and can provide crucial information during many stages, like exploration, economic appraisal, and production. While, in CCS, geological setting is very important for sustainable storage of CO2, into the geological formations, to prevent global warming. As it seems Geothermal Resources and CCS are becoming more favorable and profitable, over time, especially with the development of new technologies and solutions. Greece appears to have huge potential in many locations for both projects

Cardiopulmonary Exercise Performance of Children Born Non-Extremely Preterm

Data on exercise tolerance of children born non-extremely preterm are sparse. We aimed to explore the cardiopulmonary exercise testing (CPET) characteristics in this population. We studied 63 children (age 7–12 years) born at 290/7–366/7 weeks of gestation (34 were late preterm, 29 were preterm) and 63 age-matched, term-born controls. All performed spirometry and CPET (cycle ergometry). There were no differences in activity levels and spirometric parameters between the group of preterm-born children and controls. A peak oxygen uptake (VO2peak) of p = 0.001). Term-born participants presented similar VO2peak to late-preterm children but higher than those born at 0/7 weeks of gestation (p = 0.002). Ventilatory limitation was noted in 4.8% of term and 7.9% of preterm participants, while only one preterm child presented cardiovascular limitation. Children born before 34 weeks of gestation had higher respiratory rates and smaller tidal volumes at maximum exercise, as well as lower oxygen uptake for the level of generated work. We conclude that school-age children born at 29–34 weeks of gestation may present decreased exercise performance attributed to an altered ventilatory response to exercise and impaired O2 utilization by their skeletal muscles rather than other cardiopulmonary limiting factors