Search results for " mineral"
showing 10 items of 541 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…
Die chemische molekulargewichtsbestimmung von polystyrol mit hilfe colorimetrisch bestimmbarer endgruppen. III. Mitt.
1964
Ein mit dem Diacylperoxyd der 3-Benzolazo-benzoesare hergestelltes Polystyrol enthalt Endgruppen, die durch Extinktionsmessungen bei 442, 319 und 262,5 mμ bestimmt wurden. Es wurde eine Extinktionszahl-Molekulargewichts-Beziehung aufgestellt, die dem bekannten VAN'T HOFFschen Gesetz entspricht. Falls die Zahl der charakteristisch absorbierenden Endgruppen je Makromolekul unbekannt ist, wurden fur die experimentelle Bestimmung eines Mindestmolekulargewichts mehrere voneinander unabhangige Gleichungen gefunden. Viskosimetrisch und uber Extinktionsmessungen bestimmte Molekulargewichte wurden verglichen. Polystyrene, prepared by means of a diacylperoxide of the 3-benzeneazobenzoic acid, contain…
Hafnium-neodymium isotope evidence for enhanced weathering and tectonic-climate interactions during the Late Cretaceous
2022
<p>Over million-year timescale the carbon cycle evolution is driven by mantle CO<sub>2</sub> degassing (source) and by continental weathering that drawdowns atmospheric CO<sub>2</sub> through silicate weathering reactions (sink). Based on a novel geochemical proxy of chemical weathering intensity (i.e. using measurements of Hf and Nd isotope ratios in clay-size fractions of sediments) and clay mineralogy, we discuss the links between tectonic, continental weathering and climate evolution during the late Cretaceous. That period records the very first step of the last greenhouse to icehouse transition and is concomitant to …
CLAYS IN COSMETICS AND PERSONAL-CARE PRODUCTS
2021
Clays are used in various cosmetic formulations, such as sunscreens, toothpastes, deodorants, creams, hair cosmetics, makeups, nail polish, facial masks, and shampoos, among others, to improve the organoleptic and physicochemical characteristics, to increase the stability, or to facilitate elaboration. Together with their technological functionalities, clays are cosmetologically active ingredients with cleaning, anti-aging, anti-wrinkling, and sun-care functionalities. Talc, kaolinite, mica, and some smectites are the clay minerals used most frequently in cosmetic products, but several other phyllosilicates as well as modified and synthetic clays are also used. Sometimes, clays are useful i…
Quantitative identification, distribution and source apportionment of anthropogenic trace metals in marine sediment of Milazzo gulf (N-E Sicily): pre…
2009
Green coffee, bioactive compounds’ analysis of experimental cultivation in Sicily: a new frontier in the Sicilian food sector
2023
Recently, climate change represents a new possibility for tropical cultivars fruit in Mediterranean areas. The focus of this work is the evaluation of the real possibility of coffee cultivation in Sicily, like coffee plants grown in tropical and subtropical regions. The objective was to evaluate plant adaptation to our climate and to study the chemical qualities of green coffee pulps and seeds: total phenolic content, antiradical capacity, fatty acids, amino acids, alkaloids, vitamins, proximate composition, polyphenolic profile and other bioactive compounds of cosmetic, pharmaceutical and agrary interest. Temperature, light and vegetative growth of Coffea arabica L. cv. “Caturra” plants we…
CONFRONTO TRA FERTIRRIGAZIONE CON ACIDI MINERALI E CON CONCIMI CONVENZIONALI
1994
Utilisation des minéraux lourds comme indicateurs de paléoplacers alluvionnaires diamantifères en République centrafricaine (RCA). Use of heavy miner…
2001
International audience; Le diamant est la première ressource minérale de la République Centrafricaine (RCA). Exclusivement exploité par plusieurs sociétés minières avant 1960, il l'est maintenant de façon artisanale. Avec une production annuelle d'envi-ron 500 000 carats (1 carat = 0,2 g), la RCA est le dixième producteur de diamant (en valeur) dans le monde. Les diamants gemmes (pierres de joaillerie, taillables) représentent 70 à 75 % de la production. Deux principales zones diamantifères présentant une relation spatiale évidente existent en RCA : la Formation de Mouka-Ouadda à l'Est et celle de Carnot à l'Ouest. Ces formations, représentant les 'roches magasins' du diamant, constituent a…
The Billiemi breccia: the record of Rhaetian/lowermost Jurassic brittle deformations along the Panormide shelf edge
2010
Effects of Tray-Drying on the Physicochemical, Microbiological, Proximate, and Sensory Properties of White- and Red-Fleshed Loquat (Eriobotrya Japoni…
2022
Loquat fruits, highly valued by consumers for their characteristic aroma and pleasant taste, have a short post-harvest life and are susceptible to mechanical damage, loss of firmness, and initial organoleptic characteristics. The aim of this work was to develop a drying method suitable for storing loquat fruits in polyamide/polyethylene (PA/PE) bags containing two gaseous mixtures (treatments): MAPN2 (100% N2) and MAPP (21% O2 and 0.04% CO2), at room temperature (20 ± 1 °C) for at least 2 months. The effects of these conditions on the physico-chemical, microbiological, proximate, and sensory properties of fruit stored over a 50-day time interval were studied. The results showed that convect…