Search results for "Magnetism"
showing 10 items of 1934 documents
Geophysical investigations in the Flumendosa River Delta, Sardinia (Italy) — Seismic reflection imaging
2006
A geophysical investigation that included seismic-reflection surveying and time-domain electromagnetics (EM) was carried out in the Flumendosa River Delta plain in southeastern Sardinia, Italy. The objective was to improve knowledge of geologic and hydrogeologic controls on a highly productive aquifer hosted in thick Quaternary deposits and known to be affected by an extensive saltwater intrusion. The seismic reflection survey, whose results are reported here, aimed to image the Paleozoic bedrock topography and to obtain detailed structural and stratigraphic information on the sequence of largely fluvial sediments extending from the surface down to bedrock. The survey consisted of two inli…
Palaeomagnetism of the central Cuban Cretaceous Arc sequences and geodynamic implications
2009
Abstract A detailed palaeomagnetic study of Cretaceous age volcanic and sedimentary arc rocks from central Cuba has been carried out. Samples from 32 sites (12 localities) were subjected to detailed demagnetisation experiments. Nineteen sites from the Los Paso, Matagua, Provincial and Cabaiguan Formations yielded high unblocking temperature, dual polarity directions of magnetisation which pass the fold tests with confidence levels of 95% or more and are considered to be primary in origin. The palaeomagnetic inclinations are equivalent to palaeolatitudes of 9°N for the Aptian, 18°N for the Albian. A synfolding remanence identified in 5 sites from the younger Hilario Formation indicates a lat…
The Palaeomagnetism of the Permian Rocks of the Black Forest, Germany
1972
Summary Palaeomagnetic measurements made upon Permian samples from the Black Forest, Odenwald and Pfalzerwald (excluding those measurements on samples from the Schopfheim basin) are consistent with those from north-western Europe. The virtual pole based upon 18 sites is 174.9°E. 48.4N. The measurements made on the fine-grained shales and mudstones from the Schopfheim basin are significantly different from the preceding. Since incorrect age assignment, sampling, components of secondary magnetic and tectonic effects can be excluded, the difference is attributed to incomplete removal of the effects of secular variation. The Scharfenstein massif previously regarded as Permian, was found to have…
Correlation of welded ignimbrites on Pantelleria (Strait of Sicily) using paleomagnetism
2011
Although the oldest volcanic rocks exposed at Pantelleria (Strait of Sicily) are older than 300 ka, most of the island is covered by the 45–50 ka Green Tuff ignimbrite, thought to be related to the Cinque Denti caldera, and younger lavas and scoria cones. Pre-50 ka rocks (predominantly rheomorphic ignimbrites) are exposed at isolated sea cliffs, and their stratigraphy and chronology are not completely resolved. Based on volcanic stratigraphy and K/Ar dating, it has been proposed that the older La Vecchia caldera is related to ignimbrite Q (114 ka), and that ignimbrites F, D, and Z (106, 94, and 79 ka, respectively) were erupted after caldera formation. We report here the paleomagnetic direc…
Application and evaluation of biomagnetic and biochemical monitoring of the dispersion and deposition of volcanically-derived particles at Mt. Etna, …
2010
article i nfo Article history: Received 6 August 2009 Accepted 4 January 2010 Available online xxxx Biomagnetic monitoring, using tree leaves as passive surfaces for particle collection, has been shown to be a promising technique for assessing the dispersion and deposition of particles in the context of anthropogenic pollution. By comparing leaves' magnetic properties with trace metal levels measured in the leaves, we here assess the utility of the biomagnetic technique as a sensitive, fast and inexpensive method for assessment of volcanic plume deposition. Samples of sweet chestnut leaves (Castanea sativa) were collected from the area surrounding Mt. Etna volcano in Sicily during the 2008 …
Strong Exchange Coupling in a Trimetallic Radical-Bridged Cobalt(II)-Hexaazatrinaphthylene Complex.
2016
Reducing hexaazatrinaphthylene (HAN) with potassium in the presence of 18-c-6 produces [{K(18-c-6)}HAN], which contains the S=1/2 radical [HAN](.-) . The [HAN](.-) radical can be transferred to the cobalt(II) amide [Co{N(SiMe3 )2 }2 ], forming [K(18-c-6)][(HAN){Co(N'')2 }3 ]; magnetic measurements on this compound reveal an S=4 spin system with strong cobalt-ligand antiferromagnetic exchange and J≈-290 cm(-1) (-2 J formalism). In contrast, the Co(II) centres in the unreduced analogue [(HAN){Co(N'')2 }3 ] are weakly coupled (J≈-4.4 cm(-1) ). The finding that [HAN](.-) can be synthesized as a stable salt and transferred to cobalt introduces potential new routes to magnetic materials based on …
Demo 48. Histéresis magnética
2013
Objetivo: Mostrar la presencia de dominios magnéticos en un medio ferromagnético, su evolución en presencia de un campo magnético externo, visualizando el fenómeno de histéresis.
Fe and Zn co-substituted beta-tricalcium phosphate (β-TCP): Synthesis, structural, magnetic, mechanical and biological properties
2020
This work was supported by the European Social Fund under the No. 09.3.3- LMT-K-712 “Development of Competences of Scientists, other Researchers and Students through Practical Research Activities” measure. AK would like to express sincere gratitude for Fellowship administrated by The Japan Society for the Promotion of Science (JSPS). Fellow’s ID No.: L12546. Authors are grateful to R. Vargalis (Vilnius University) for taking SEM images. © 2020. This work is licensed under a CC BY-NC-ND license.
Geminal parahydrogen-induced polarization: accumulating long-lived singlet order on methylene proton pairs
2020
In the majority of hydrogenative parahydrogen-induced polarization (PHIP) experiments, the hydrogen molecule undergoes pairwise cis addition to an unsaturated precursor to occupy vicinal positions on the product molecule. However, some ruthenium-based hydrogenation catalysts induce geminal hydrogenation, leading to a reaction product in which the two hydrogen atoms are transferred to the same carbon centre, forming a methylene (CH2) group. The singlet order of parahydrogen is substantially retained over the geminal hydrogenation reaction, giving rise to a singlet-hyperpolarized CH2 group. Although the T1 relaxation times of the methylene protons are often short, the singlet order has a long…
Enhanced Permeability and Retention-like Extravasation of Nanoparticles from the Vasculature into Tuberculosis Granulomas in Zebrafish and Mouse Mode…
2018
The enhanced permeability and retention (EPR) effect is the only described mechanism enabling nanoparticles (NPs) flowing in blood to reach tumors by a passive targeting mechanism. Here, using the transparent zebrafish model infected with Mycobacterium marinum we show that an EPR-like process also occurs allowing different types of NPs to extravasate from the vasculature to reach granulomas that assemble during tuberculosis (TB) infection. PEGylated liposomes and other NP types cross endothelial barriers near infection sites within minutes after injection and accumulate close to granulomas. Although similar to 100 and 190 nm NPs concentrated most in granulomas, even similar to 700 nm liposo…