759 research outputs found
Environmental ethics: values in and duties to the natural world (summarized with commentary by Panagiotis Perros)
No full textSummarized with commentary in Greek by Panagiotis Perros.Environmental ethics stands on a frontier, as radically theoretical as it is applied. Alone, it asks whether there can be nonhuman objects of duty. Animals, plants, endangered species, ecosystems, and even Earth are progressively unfamiliar as objects of duty, and puzzles arise both for theory and practice. Answers to such questions are as urgent as any humans face, and intimately related to the four principal issues on the world agenda: peace, population, development, and environment
The impact of fusion on adjacent levels in cervical spine injuries: Is it really important?
No full textObjective: although the literature on degenerative disease of the cervical spine contains numerous articles studying the changes on levels adjacent to a fusion, there exist very few such studies concerning cervical spine stabilization for trauma. Methods: over a 16-year period (1989-2005), one hundred and twelve patients underwent stabilization of the lower cervical spine (C3-T1) for subaxial cervical spine injuries, either with an anterior or posterior procedure, or both. Eighty-one patients with adequate follow-up were included in the study and 3 groups were identified: Group A, consisting of 8 patients who underwent anterior stabilization and developed Adjacent Level Ossification Development (ALOD), Group B, comprising 53 patients who were anteriorly plated but who did not develop ALOD and Group C, comprising 20 patients who received posterior stabilization. Results: eight out of 61 patients (13.1%) who were anteriorly operated developed ALOD in 11 adjacent levels (Group A). Severe (grade 3) ossification was noted in 6/8 patients at the cranial adjacent level, and in 2/8 patients at the caudal one. Three out of 8 patients presented with early ALOD at 3, 4 and 18 months respectively. Despite the radiographic abnormalities showing ossification, all the patients had an uncomplicated course without symptoms. All the radiographs of Group B and Group C patients demonstrated grade 0 ossification for both the cranial and caudal adjacent levels. Conclusion: adjacent-level ossification in cervical spine injuries may appear very early in the postoperative period and it can have a different course than in the degenerative disc disease population, at least in some patients. The first cephalad level adjacent to a fusion appears to be at greater risk. However, even when ALOD is evident radiographically, it very rarely produces any symptoms. © 2009
Corrigendum to “Delta SARS-CoV-2 variant is entirely substituted by the omicron variant during the fifth COVID-19 wave in Attica region” [Sci. Total Environ., 856(Pt 1) (2023)/159062] (Science of the Total Environment (2023) 856(P1), (S0048969722061617), (10.1016/j.scitotenv.2022.159062))
No full textThe authors state that the printed version of the above article missed the contribution of an author, which was that the third author had contributed to the writing of the original draft in addition to methodology. The correct and final version follows. CRediT authorship contribution statement Aikaterini Galani: Methodology, Validation, Writing – original draft. Athina Markou: Supervision, Writing – review & editing, Project administration. Lampros Dimitrakopoulos: Methodology, Writing – original draft. Aikaterini Kontou: Validation. Marios Kostakis: Validation. Vasileios Kapes: Methodology. Marios A. Diamantopoulos: Formal analysis, Software. Panagiotis G. Adamopoulos: Formal analysis. Margaritis Avgeris: Formal analysis, Writing– review & editing. Evi Lianidou: Writing – review & editing. Andreas Scorilas: Formal analysis. Dimitrios Paraskevis: Writing – review & editing. Sotirios Tsiodras: Writing – review & editing. Meletios-Athanasios Dimopoulos: Funding acquisition, Writing – review & editing. Nikolaos Thomaidis: Conceptualization, Project administration, Visualization, Resources. © 2022 Elsevier B.V
R-CAUSTIC: Rippling CAUSTICs underwater Image dataset
No full text<p><strong>Description</strong></p><p>Rippling caustics seem to be the main factor degrading the underwater RGB image quality and affecting the image- based 3D reconstruction process in very shallow waters. These effects are adversely affecting image matching algorithms by throwing off most of them, leading to less accurate matches and causing issues in the Simultaneous Localization and Mapping (SLAM) based navigation of the Remotely Operated Vehicles (ROV) and Autonomous Underwater Vehicles (AUV) on shallow waters. Also, they are the main cause for dissimilarities in the generated textures and orthoimages. In order to fill the gap in the literature regading underwater rippling caustics imagery with real ground truth and reference images, the first real-world underwater caustics benchmark dataset which contains 1465 underwater images is presented. Together with the RGB imagery, the corresponding generated ground truth images are delivered for facilitating the training and testing of machine learning and deep learning methods for image classification. R-CAUSTIC dataset also provides the necessary data to evaluate, at least to some extent, the performance of 3D reconstruction approaches. Data were acquired using a GoPro Hero 4 Black action camera with image dimensions of 4000 x 3000 pixels, focal length of 2.77mm and pixel size of 1.55μm and a tripod. Action cameras are widely used for underwater image acquisition. The dataset was captured in near-shore underwater sites at depths varying from 0.5 to 2m. No artificial light sources were used. Due to the wind, the turbulent surface of the water created dynamic rippling caustics on the seabed. In total 1465 RGB images were collected, separated in 7 different datasets; five of them containing stereo images, one of them tri-stereo images and one consists of multi-stereo imagery acquired in 7 different camera poses.</p><p> </p><p><strong>Publication</strong></p><p>The paper is availbale in Open Access here: https://ieeexplore.ieee.org/document/10172291</p><p><strong>If you use this dataset please cite it as R-CAUSTIC</strong> [Reference].<br>[Reference]: <strong>P. Agrafiotis, K. Karantzalos and A. Georgopoulos, "Seafloor-Invariant Caustics Removal From Underwater Imagery," in </strong><i><strong>IEEE Journal of Oceanic Engineering</strong></i><strong>, vol. 48, no. 4, pp. 1300-1321, Oct. 2023, doi: 10.1109/JOE.2023.3277168.</strong></p><p>BibTeX:</p><p>@ARTICLE{10172291,
author={Agrafiotis, Panagiotis and Karantzalos, Konstantinos and Georgopoulos, Andreas},
journal={IEEE Journal of Oceanic Engineering},
title={Seafloor-Invariant Caustics Removal From Underwater Imagery},
year={2023},
volume={48},
number={4},
pages={1300-1321},
doi={10.1109/JOE.2023.3277168}}</p><p> </p>
R-CAUSTIC: Rippling CAUSTICs underwater Image dataset
No full text<p> </p>
<h3><strong>Version 2 available! Please make sure to download the latest version of the dataset! <br></strong></h3>
<p> </p>
<p><strong>Description</strong></p>
<p>Rippling caustics seem to be the main factor degrading the underwater RGB image quality and affecting the image- based 3D reconstruction process in very shallow waters. These effects are adversely affecting image matching algorithms by throwing off most of them, leading to less accurate matches and causing issues in the Simultaneous Localization and Mapping (SLAM) based navigation of the Remotely Operated Vehicles (ROV) and Autonomous Underwater Vehicles (AUV) on shallow waters. Also, they are the main cause for dissimilarities in the generated textures and orthoimages. In order to fill the gap in the literature regading underwater rippling caustics imagery with real ground truth and reference images, the first real-world underwater caustics benchmark dataset which contains 1465 underwater images is presented. Together with the RGB imagery, the corresponding generated ground truth images are delivered for facilitating the training and testing of machine learning and deep learning methods for image classification. R-CAUSTIC dataset also provides the necessary data to evaluate, at least to some extent, the performance of 3D reconstruction approaches. Data were acquired using a GoPro Hero 4 Black action camera with image dimensions of 4000 x 3000 pixels, focal length of 2.77mm and pixel size of 1.55μm and a tripod. Action cameras are widely used for underwater image acquisition. The dataset was captured in near-shore underwater sites at depths varying from 0.5 to 2m. No artificial light sources were used. Due to the wind, the turbulent surface of the water created dynamic rippling caustics on the seabed. In total 1465 RGB images were collected, separated in 7 different datasets; five of them containing stereo images, one of them tri-stereo images and one consists of multi-stereo imagery acquired in 7 different camera poses.</p>
<p> </p>
<p><strong>Publication</strong></p>
<p>The paper is availbale in Open Access here: https://ieeexplore.ieee.org/document/10172291</p>
<p><strong>If you use this dataset please cite it as R-CAUSTIC</strong> [Reference].<br>[Reference]: <strong>P. Agrafiotis, K. Karantzalos and A. Georgopoulos, "Seafloor-Invariant Caustics Removal From Underwater Imagery," in </strong><em><strong>IEEE Journal of Oceanic Engineering</strong></em><strong>, vol. 48, no. 4, pp. 1300-1321, Oct. 2023, doi: 10.1109/JOE.2023.3277168.</strong></p>
<p>BibTeX:</p>
<p>@ARTICLE{10172291, author={Agrafiotis, Panagiotis and Karantzalos, Konstantinos and Georgopoulos, Andreas}, journal={IEEE Journal of Oceanic Engineering}, title={Seafloor-Invariant Caustics Removal From Underwater Imagery}, year={2023}, volume={48}, number={4}, pages={1300-1321}, doi={10.1109/JOE.2023.3277168}}</p>
<p> </p>
Does genetic diversity on corporate boards lead to improved environmental performance?
No full textElsevier
Journal of International Financial Markets, Institutions and Money
Volume 84, April 2023, 101756
Journal of International Financial Markets, Institutions and Money
Does genetic diversity on corporate boards lead to improved environmental performance?
Author links open overlay panelRenatas Kizys a, Emmanuel C. Mamatzakis b, Panagiotis Tzouvanas c
Show more
Outline
Share
Cite
https://doi.org/10.1016/j.intfin.2023.101756
Get rights and content
Under a Creative Commons license
open access
Highlights
•
We examine the effect of boards’ genetic diversity (GENETICD) on corporate ESG performance.
•
ESG performance and disclosures are higher in more genetically diverse firms.
•
The positive GENETICD effect on ESG performance is driven by the environmental pillar.
•
Corporate carbon performance significantly improves with increases in GENETICD.
We study the effects of boards’ genetic diversity on corporate environmental performance. Using a multidimensional information set for 3690 US firms during the period from 2005 to 2019, and three different measures of genetic diversity, we find that, pursuant to the diversity theory, which posits that diversity improves the quality of management decisions and business ethics, genetic diversity leads to improved environmental performance. We also find that genetic diversity improves carbon and governance performance, and ESG disclosure. Particularly, a one percentage point increase in boards’ genetic diversity will increase the carbon performance, measured by the inverse of the carbon emissions to total assets ratio, and environmental performance by 3.54% and 5.57%, respectively. Our results remain robust to different model specifications, while also controlling for endogeneity. In terms of policy implications, results suggest that the key to tackling climate challenges is to promote boards’ genetic diversity
Dataset in support of the Southampton doctoral thesis 'The boatbuilding tradition of the Aegean during the Late Neolithic – Early Bronze Age periods. Typological classification, digital reconstruction and seakeeping assessment'
No full textDataset in support of the Southampton doctoral thesis 'The boatbuilding tradition of the Aegean during the Late Neolithic – Early Bronze Age periods. Typological classification, digital reconstruction and seakeeping assessment' Appendix D - Resistance data and Appendix C - Stability data.
This dataset is focused on two appendices:
Appendix D - Resistance data. D.1 Resistance data produced by the author via MAXSURF Resistance for this thesis.
Appendix C - Stability data
C1. Stability data – STIX and ISO criteria, produced by the author via MAXSURF Stability software for his thesis
This research was funded by Southampton Marine and Maritime Institute (SMMI), Vice-Chancellor's Scholarship, Greek Archaeological Committee UK (GACUK)
</span
CFD modeling and experimental characterization of urea/water solution injection inside SCR systems of diesel engines
No full textIl lavoro proposto pone l'attenzione sulla caratterizzazione dell'iniezione a bassa pressione utilizzata nella sezione pre-catalitica di un sistema per la riduzione di ossidi d'azoto (Selective Catalytic Reduction) applicato a veicoli. La Phase Doppler Anemometry rappresenta il principale strumento per la valutazione delle proprietà cinematiche di uno spray in condizioni operative realistiche. La dimensione e la velocità delle gocce iniettate da due diversi iniettori è misurata principalmente attraverso l'uso di un banco prova in grado di riprodurre le condizioni termo-fluidodinamiche di un sistema di rimozione inquinanti. I dati sono utilizzati, in accoppiamento con la visualizzazione della morfologia dello spray attraverso Shadow Imaging, per inizializzare i modelli di iniezione da inserire in simulazioni CFD con approccio Lagrangiano-Euleriano realizzate con il software open-source OpenFOAM. I risultati numerici sono validati sulla base di dati raccolti rispettivamente nella regione d'iniezione e vicino alla superficie solida di impatto dello spray. La cospicua frazione di massa liquida che interagisce con le pareti del sistema è quantificata attraverso un patternator meccanico in grado di produrne una distribuzione spaziale. Le misure mostrano che più' della metà del liquido iniettato impatta con la parete solida del sistema, in qualsiasi condizione di flusso gassoso. Le simulazioni fluidodinamiche sono usate per valutare l'intrusività dello strumento nel sistema e successivamente sono comparate ai risultati di flusso di massa liquida, sottolineando come l'assegnazione di un numero costante di gocce ad ogni parcel computazionale migliori la rappresentazione dello spray. Un modello di interazione spray-parete basato su dati di letteratura è stato implementato nel codice, introducendo una soglia termica nell'identificazione del regime di impatto e risolvendo lo scambio termico con le superfici del sistema. L'interazione termica diretta tra gocce e solido è identificata come il termine principale nel bilancio termico delle pareti solide, ed è rappresentata con mappe di impatto che sintetizzano il fenomeno. Dal punto di vista dello spray, l'interazione con le pareti rappresenta l'unica sorgente di break-up delle gocce primarie, che non riescono a essere deviate dal flusso gassoso.The present work focuses on the characterization of the low-pressure driven injection applied to the pre-catalytic section of a Selective Catalytic Reduction system for vehicle applications. Phase Doppler Anemometry represents the main technique to assess the spray kinematic features in cross-flow conditions in a very confined environment. The experiments are mostly carried out in a test bench able to reproduce Diesel engine exhaust after-treatment operating conditions, providing size and velocity distributions of the droplets generated by two different commercially available injectors. The data are used, coupled with qualitative Shadow Imaging visualizations of the sprays, to initialize a numerical injection model for each nozzle, to be included in a Lagrangian-Eulerian framework handled with the open-source platform OpenFOAM. The CFD simulation is validated on the near-nozzle behavior in quiescent air and on the data collected close to the primary impingement surface in cross-flow conditions. A conspicuous fraction of the liquid mass impacts the surface and its quantification is carried out with a mechanical patternator, producing spatially resolved mass distributions and showing that the entrainment in cross-flow is always less than the 50% of the injected mass. The simulation is used to estimate the intrusiveness of the instrument in the system, and then it is compared to the mass flux data, highlighting the improvement produced by the fixed number of droplets per parcel approach in the definition of the dispersed phase. A literature based spray-wall interaction model is implemented in the CFD code, introducing a thermal threshold on the interaction regime identification and the conductive heat transfer between spray and walls, which are solved in their thermal transients. The direct interaction of the droplets with the solid surfaces is identified as the paramount term in the walls energy balance, and is represented with synthetic impingement maps. On the other hand the impact on the walls is found to be the only source of break-up for the primary droplets, which are not deflected by the flow.DIPARTIMENTO DI ENERGIA29ONORATI, ANGELOBOTTANI, CARLO ENRIC
Emission reduction by targeted transient <delta> operations in three-way catalysts for heavy-duty natural gas applications
No full textTo curb the severe effects of climate change, our society needs to radically reduce its CO2 footprint. For the heavy-duty sector, where electrification is difficult, alternative fuels can be the solution. Methane-fueled engines have lower energy-specific CO2 emissions than conventional Diesel-fueled engines. Furthermore, they have the potential of becoming carbon-neutral, when combined with bio-methane/synthetic methane. However, oxidation of unburnt methane in the exhaust gas poses a challenge for aftertreatment systems. The aim of this thesis is to investigate the mechanism of methane abatement and to reveal methods to reduce methane and other hazardous gas emissions. The majority of the experiments were conducted directly on an engine test bench, which is rarely seen in studies focusing on catalytic reaction pathways.
Initial investigations focused on methane abatement under steady state and λ-step transitions. Under steady state, the presence of oxygen was identified as a prerequisite for methane conversion. Reacting with oxygen is the only methane conversion pathway. However, after step transition from oxygen excess conditions (slightly lean) to oxygen-poor conditions (slightly rich), high methane conversion was observed under rich conditions with no oxygen available. This high conversion was attributed to steam reforming (SR), which was activated by the step transition. The SR reaction rate decreased over time when staying at rich conditions, until full deactivation. Investigations in the lab-scale model gas reactor confirmed this analysis. In addition, the reason for SR deactivation was identified by DRIFTS measurements as the accumulation of carbonates on the catalytic surface, blocking the active sites.
Based on the identified importance of the SR reaction, targeted λ oscillations across stoichiometry were introduced, in order to repeatably activate SR and achieve sustainable high methane conversion. During the rich parts of the oscillations, methane was converted via SR, while, during lean parts, the carbonates were periodically removed from the catalyst surface. With these oscillations, methane conversion has been significantly improved, in comparison to steady state. In parallel, a numerical model has been developed in order to simulate the catalyst behavior under oscillating conditions. The model provided insights on the reaction pathways and their distribution along the catalyst axis.
The catalytic activity of the different Platinum-group metals has been investigated for the identified reactions. Various catalysts of different compositions were tested under cold start, λ oscillations and quasi-steady state conditions. Both Pt and Pd activated SR reactions, however SR attenuation was faster in Pt catalysts. In lean conditions, Pt exhibited higher methane oxidation. Rh was identified as important for enhancing NOx reduction and lowering NH3 emissions. The combination of all three metals has improved the overall catalyst performances.
In the final part of the thesis, a special aftertreatment system was investigated. It combines a Pd/Rh catalyst subject to stoichiometric conditions with a Pt oxidation catalyst subject to lean conditions. In the Pd/Rh catalyst, methane was removed via λ oscillations. In the Pt catalyst, the remaining CO, H2 and NH3 were oxidized. The setup provided a novel perspective in reducing the overall environmental impacts.GR-KR
Ideas in trenches: Power and polemics in Panagiotis Kondylis
No full textThe author of the article attempts to examine the positions of Panagiotis Kondylis on the intellectual history and ideas’ polemical nature that is the basic feature for understanding the configuration and development of an idea-theory in history. In order to achieve a full understanding of the specific concept of the intellectual history, first of all we have to analyze the Greek thinker's positions on the power and the way in which the search for power as a basic and irrevocable anthropological condition leads to a polemic condition within the social field. This polemic condition is also evident in the field of ideas, as ideas can be seen as the attempt to form worldviews by the respective subject or group of subjects that have the purpose of self-preservation and expanding their power. Therefore, in this article the emphasis is placed on two different areas of Kondylis' thought, the philosophy of man and then on the description of the ideas’ formulation. 
- …
