Search results for "LCA"
showing 10 items of 1995 documents
The influence of weathering processes on labile and stable organic matter in Mediterranean volcanic soils
2008
The relationship and mechanisms among weathering processes, cation fluxes, clay mineralogy, organic matter composition and stability were studied in soils developing on basaltic material in southern Italy (Sicily). The soils were transitions between Phaeozems and Vertisols. Intense losses of the elements Na, Ca and Mg were measured indicating that weathering has occurred over a long period of time. The main weathering processes followed the sequence: amphibole, mica, volcanic glass or if ash was the primary source→smectite→interstratified smectite–kaolinite→kaolinite. Kaolinite formation was strongly related to high Al, Mg and Na losses. The good correlation between oxyhydroxides and kaolin…
Tracing the source of gypsum in New Caledonian soils by REE contents and SSr isotopic compositions
1998
Gypsum minerals forming in pedogenic environments in New Caledonia were examined for their S and Sr isotope compositions and REE distributions. Three possible sources were identified: volcanic, soil-derived and marine. However, differentiation based only on the REE contents and normalized patterns was not possible, but, the best preserved volcanic sample yields a negative EuEu∗ anomaly and the lowest GdNYbN ratio due to the high content of organic matter. Mixing calculations of the δ34S values and 87Sr86Sr ratios confirmed that the marine gypsum has a δ34S value close to + 21‰ and an 87Sr86Sr ratio close to 0.70912, and that the volcanic gypsum has a δ34S value of 0‰ and an 87Sr86Sr ratio o…
Massenspektrometrische Untersuchungen an Edukten für die Synthese H2-aktiver Substanzen
1982
Unter den Bedingungen der Elektronenstosionisation wurden 4-[(2-Aminoethoxy)-methyl]-5-methyl-imidazo (1), die Imidazolderivate mit N-substituierter Ethylendiamin-Struktur 2–5 sowie die Imidazolcarboxamide 6–8 massenspektrometrisch untersucht. Der Mechanismus der konkurrierenden Bindungsspaltungen und der Umlagerungsprozesse wird formuliert. Die Wechselwirkung der funktionellen Gruppen sowie deren Einflus auf das Fragmentationsverhalten der Substanzen wird beschrieben und ein Schema der Hauptfragmentierungswege vorgeschlagen. Mess Spectrometry of Reactants for the Synthesis of H2-Active Compounds 4-[(2-Aminoethoxy)methyl]-5-methylimidazole (l), the imidazoles 2-5 with N-substituted ethylene…
On the occurrence of ClO in cirrus clouds and volcanic aerosol in the tropopause region
1997
Airborne observations during descents of the ER-2 through layers of volcanic aerosol (Mount Pinatubo eruption of 1991) and a cirrus cloud are utilized to study the the abundance of ClO and its relation to aerosol surface area in the midlatitude tropopause region. During a cirrus event near the tropopause ClO mixing ratios up to 2.7 pptv were detected and near the tropopause ClO levels from a few to 70 pptv were found. These measurements are associated with large experimental uncertainties but demonstrate the possible presence of ClO inside cirrus clouds and near the tropopause. Model calculations show that possible enhancements of ClO by heterogeneous chemistry on cirrus cloud particles cou…
Umsetzungen an höhermolekularen, molekulareinheitlichen phenol-formaldehyd-kondensaten
1960
An in eindeutiger Synthese und im praparativen Masstab zuganglich gewordenen hohermolekularen, molekulareinheitlichen Phenol-Formaldehyd-Kondensaten (Mol.-Gew. bis zu 1500) wird die Acetylierung, die Umsetzung mit Diphenylcarbamidsaure-chlorid zu Poly-[N-diphenyl-]urethanen und mit Formaldehyd und Dimethylamin zu MANNICH-Basen untersucht. Bei den zwei ersten Umsetzungen wird mit Hilfe der Elementaranalyse bzw. der Acetylbestimmung sowie der UR-Spektren zu unterscheiden versucht, ob alle Hydroxygruppen einer Molekel umgesetzt werden konnen. Die Elementaranalysen der erhaltenen MANNICH-Basen zeigen, das eine vollstandige Einfuhrung von Endgruppen (kettenanaloge Umsetzung) gelungen ist. Higher…
CO2 vents areas show effects of ocean acidification on benthic rocky shores assemblages
2011
Climatic and environmental changes of the last 10 kyr in the central Mediterranean. A study of a core collected in the Gulf of Termini (Sicily, Italy)
2009
Analysis of the relationship between chemistry composition and stable isotope signals in coastal sediments: a biogeochemistry study to assess the env…
2008
1987. La protesta estudiantil contra el Gobierno socialista. La Generalitat Valenciana y el conflicto estudiantil. "El acuerdo valenciano" del consel…
2006
1987. La protesta estudiantil contra el Gobierno socialista. La Generalitat Valenciana y el conflicto estudiantil. "El acuerdo valenciano" del conseller Ciprià Císcar. La hegemonía socialista en la Comunidad Valenciana. El PSPV-PSOE. 1982-1995 La protesta estudiantil contra el Gobierno socialista. En diciembre de 1986 estallaría un conflicto entre el Ministerio de Educación y los estudiantes de Bachillerato -BUP- y formación profesional -FP-, que se extendería a profesores, y que tendría paralizada la enseñanza más de dos meses. Las manifestaciones y huelgas generales eran nacionales contra las políticas del ministro de Educación y Ciencia, José María Maravall, y que afectaría a la Generali…
First gas flux measurements of conduit permeability decrease prior to Strombolian eruption at Stromboli volcano (Italy)
2016
Strombolian eruptions can be described in terms of growth, coalescence, and rise of a gas pocket (aka slug) bursting at the surface of a vent. This model overlooks that the transition to explosive regimes is mostly controlled by the permeability in the upper part of a volcanic conduit. We report here on the first gas flux measurements of Strombolian explosions from a vent that exhibited a significant decrease of passive degassing tens of second prior to the onset of the explosion. This particular explosive activity took place during the July 2014 lava overflows, when the magma level inside the conduit rose up to the crater terrace. The amount of gas that accumulated before the eruption is i…