Search results for " element"
showing 10 items of 2679 documents
Impact of Etna’s volcanic emission on major ions and trace elements composition of the atmospheric deposition
2022
Mt. Etna, on the eastern coast of Sicily (Italy), is one of the most active volcanoes on the planet and it is widely recognized as a big source of volcanic gases (e.g., CO2 and SO2), halogens, and a lot of trace elements, to the atmosphere in the Mediterranean region. Especially during eruptive periods, Etna’s emissions can be dispersed over long distances and cover wide areas. A group of trace elements has been recently brought to attention for their possible environmental and human health impacts, the Technology-critical elements. The current knowledge about their geochemical cycles is still scarce, nevertheless, recent studies (Brugnone et al., 2020) evidenced a contribution from the vol…
Chemistry and fluxes of major and trace element from worldwide passive degassing volcanoes: a critical review
2015
Volcanic emissions represent one of the most important natural sources of trace elements (e.g. As, Cd, Cu, Hg, Pb, Sb, Tl and Zn) into the atmosphere, sequentially influencing the hydrosphere, lithosphere and biosphere. The human health hazard during episodic volcanic eruptions generally follows from deposition of coarse and fine particles (2.5-10 and < 2.5 μm) that produces effects such as asthma and lung and respiratory disease. Regarding passive degassing volcanoes, the harmful effects of fluorine fumigation are known both for vegetation (foliar necrosis) and human/animals (fluorosis), but only a few studies have been focused on the effects of potentially toxic trace elements. From a …
Are the Salinelle mud volcanoes threatening human health or are anthropogenic activities threatening the Salinelle mud volcanoes?
2012
Passive samplers were used to measure the atmospheric concentrations of SO2 naturally emitted at three volcanoes in Italy (Etna, Vulcano and Stromboli) and of H2S naturally emitted at three volcanic/geothermal areas in Greece (Milos, Santorini and Nisyros). The measured concentrations and dispersion patterns varied with the strength of the source (open conduits or fumaroles), the meteorological conditions and the area topography. At Etna, Vulcano and Stromboli, SO2 concentrations reach values that are dangerous to people affected by bronchial asthma or lung diseases (>1000 μg m−3). H2S values measured at Nisyros also exceed the limit considered safe for the same group of people (>3000 μg m−…
Geochemical characterization of trace elements in thermomineral waters of Greece
2020
Trace elements have a fundamental role in natural and anthropogenic systems. In waters, they present a great variability of concentrations that mostly depends on the degree of gaswaterrock interactions and geochemical conditions such as pH, temperature, redox and/or exchange reactions, etc. Even though, they are present in very low contents in hostrocks, elevated concentrations in ground or surface waters may have a hazardous impact on human and animal health and thus, it is important to both quantify and try to understand their behaviour in natural systems. Here we present the results of about 300 cold and thermal mineral waters collected along the entire Hellenic territory. Physicochemica…
Accumulation and effects of Cd, Pb and Zn in blackbirds (Turdus merula) along a heavy metal pollution gradient.
2009
Skrzydlate słowa w demotywatorach
2020
The observation of winged words on the Internet shows that the most memorable ones are those that come from the school reading canon and that they become an element of verbal-visual games in demotivators. At the same time, the Internet has become a catalyst, a place where very quickly the emergence of new units takes place. It is infl uenced by its unlimited range and technical capabilities that allow copying, duplication and modifi cation of new units. Adding a graphical element to them in the demotivators strengthens their impact on the recipient, allows them to evoke various emotions and, as a result, easier to remember and willing to share them with subsequent Internet users.
An IPMSM torque/weight and torque/moment of inertia ratio optimization
2014
In this paper, a torque/weight and torque/moment of inertia ratio optimization procedure for interior permanent magnet syncronous motors (IPMSMs) is presented. More in detail, a performance comparison between several IPMSM rotor structures has been carried out in order to determine the optimum geometry that can maximize the torque/weight and torque/moment of inertia ratios. A commercial motor, with known electrical and mechanical characteristics, has been taken as reference. Its rotor structure has been modified several times, obtaining different rotor geometries and, therefore, many IPMSM models with different electrical and mechanical characteristics. The finite element method (FEM) analy…
Radioaktivitāte
2023
Mācību grāmatas mērķis ir iepazīstināt lasītāju ar radioaktivitātes fenomenu, jautājumiem par atoma kodola stabilitāti, radioaktīvo elementu, starojuma iedarbību un izmantošanas iespējām. --///-- Šis ir nekomerciāls izdevums, un visi ievietotie attēli ir tikai iepazīšanās,mācīšanās un pētniecības mērķiem, tādi, kurus neaizsargā autortiesības (Public Domain) vai arī kuru autori tos klasificējuši atbilstoši CC BY-NC-SA 4.0 licences lietojumam.
Musiikilliset elementit eläinten ääntelyssä
2017
Tämän integroivan kirjallisuuskatsauksen tarkoituksena oli tutustua eläinten ääntelyn musiikillisuuteen samalla selvittäen, millaisia musiikillisina pidettäviä elementtejä eläinten ääntelystä voidaan löytää. Lähestyin aihetta tutkimalla viittä keskeisintä musiikillista elementtiä: melodiaa, rytmiä, harmoniaa, äänenväriä sekä rakennetta ja selvittämällä aiempia tutkimuksia hyväksi käyttäen, mitkä näistä elementeistä esiintyvät eläinten ääntelyssä. Tutkimuksista kävi ilmi, että kaikki edellä mainitut viisi musiikillista elementtiä ovat - lajista riippuen - löydettävissä eläinten ääntelystä. Lisäksi huomionarvoista oli, että tutkimusten mukaan tietyt eläinlajit kykenevät paitsi hyödyntämään mu…
Contribution to the modeling of microstructural corrosion on aluminium alloys : definition of a methodology to study the bimetallic corrosion phenome…
2008
The initiation and the propagation of aluminum alloys microstructural corrosion is mainly based on the bimetallic corrosion phenomenon. This type of corrosion is caused by galvanic coupling at a local scale between the different phases contained in the alloy. The description of the localized corrosion phenomenon has been largely studied. Their complexity can explain why they are so difficult to predict by the way of numerical tools and why the works that have been done on this subject are so scarce. The present thesis brings a new contribution to this field by suggesting a methodology based on the complementary use of local electrochemical techniques and the finite element simulation of bim…