Search results for "Sedimentation"
showing 10 items of 118 documents
Tectonics, climate and deposition/erosion cycles during the Quaternary in Western Sicily
2011
Continental to marine Quaternary deposits outcrop in thin and patchily exposed successions in Western Sicily, overlying a previously deformed substrate, known as the Neogene-Early Quaternary chain. These deposits are grouped in sedimentary units bounded by unconformity surfaces. The detected unconformities, often of regional extent, allows us to define seven main synthems: a) Marsala synthem is a Lower Pleistocene 2-80 m-thick body of marine/coastal calcarenites; b) Piana di Partinico synthem is made up of 1-5 m thick marine/continental clastics located on several marine terraces related to sea level highstand phases of Middle Pleistocene (Oxygen Isotope Stages – OISs - 17-7); c) Polisano s…
Moleküldimensionen von polymeren in verschiedenen lösungsmitteln auf grund hydrodynamischer messungen
1960
Ein fraktioniertes Polystyrol vom Molekulargewicht Mw ≈ 540000 wurde in Chloroform, Toluol, Methylathylketon und Cyclohexan sowie in drei Mischungen von Toluol und Methylathylketon untersucht. Da das Chloroform ein gutes, das Cyclohexan dagegen ein Θ-Losungsmittel fur Polystyrol darstellt, nehmen die Dimensionen des Fadenmolekuls beim Ubergang zwischen den Losungsmitteln ab. Mit den Knaueldimensionen andern sich Reibung und Viskositat des Polystyrols. Messungen der Sedimentationskonstanten, der Diffusionskonstanten, der Viskositatszahl sowie der Dichte und der Zahigkeit fur die gemischten Losungsmittel wurden ausgefuhrt. Die Ergebnisse der Messungen werden benutzt, um aus der Viskositatsthe…
Sedimentation Tanks for Treating Rainwater: CFD Simulations and PIV Experiments
2021
The removal of solids is the most important step when treating rainwater. The article evaluates two designs of sedimentation tanks that can be used for the continuous separation of fine particles from water: OS—standard sedimentation tanks, and OW—swirl sedimentation tanks. The tanks were studied by conducting computational fluid dynamics (CFD) modeling and particle image velocimetry (PIV) experiments. The settling process in sedimentation tank was carried out at varying operating flow rates. A tank with a modified structure was used for the tests, where water was supplied by a nozzle placed at an angle. This solution made it possible to obtain a rotational flow that transported the suspend…
Distribution patterns of particulate trace metals in the water column and nepheloid layer of the Gulf of Riga.
2004
The dynamics (fate) of trace metals in suspended particulate matter within the Gulf of Riga has not yet been adequately addressed in the scientific literature. Therefore, during a two year period (2001-2002) samples of suspended particulate matter and surface sediments for trace metal analysis were collected in the Gulf of Riga and the Daugava river, and these data were combined with background information from the national marine monitoring program in Latvia. This paper presents a descriptive study of solid phase trace metals (aluminium, iron, cadmium, chromium, copper, manganese, nickel, lead and zinc) dynamics and their spatial distribution within the Gulf of Riga based on Principal Comp…
Variabilité pluviométrique et dynamique hydro-sédimentaire du bassin versant du complexe fluvio-lagunaire Mono-Ahémé-Couffo (Afrique de l'ouest)
2010
This thesis aims to highlight the relationship between climate and water balance process on the basin of the complex river-lagoon Mono-Aheme-Couffo. A better analysis rain/flow is made using rainfall spatialization from interpolation, taking into account altitude and geographical coordinates of hydrometeorological stations. Also, pluvio-hydrological variability and surface states dynamics impacts on sedimentation are examined. Runoff variability and sediment dynamics in the watershed Mono-Aheme-Couffo over the period 1961-2000 in a context of integrated water resources management (IWRM) were analyzed according to the rainfall depths, effects of water releases from the Nangbeto dam operation…
Dynamics of copper and zinc sedimentation in a lagooning system receiving landfill leachate.
2013
9 pages; International audience; This study characterises the sediment dredged from a lagooning system composed of a settling pond and three lagoons that receive leachates from a municipal solid waste (MSW) landfill in France. Organic carbon, carbonate, iron oxyhydroxides, copper (Cu) and zinc (Zn) concentrations were measured in the sediment collected from upstream to downstream in the lagooning system. In order to complete our investigation of sedimentation mechanisms, leachates were sampled in both dry (spring) and wet (winter) seasonal conditions. Precipitation of calcite and amorphous Fe-oxyhydroxides and sedimentation of organic matter occurred in the settling pond. Since different di…
Signatures terrigène et volcanique des bassins sédimentaires : implications stratigraphiques et paléoclimatiques
2018
Über ein verfahren zur exakten bestimmung der sedimentationskonstanten ungereinigter enzyme mit hilfe des aktivitätstestes. versuche an den glukosede…
1960
In einer normalen Ultrazentrifugenzelle wird ein Bodenbelag aus Filtrierpapier angebracht, in welchen das Enzym hineinsedimentiert. Aus dem Aktivitatsverlust oberhalb des Bodenbelags wird die Sedimentationskonstante berechnet. Durchfuhrung und Auswertung der Versuche werden zu einer Routinemethode ausgearbeitet. Die Methode wird dazu benutzt, die Sedimentationskonstanten der beiden Glukosedehydrogenasen aus Penicillium notatum bzw. Aspergillus niger zu bestimmen. Es ergibt sich 7,91 bzw. 8,81 SVEDBERG. Die nach dem fruher beschriebenen Aktivitatstest bestimmten Diffusionskonstanten sind 5,56 bzw. 4,47 · 10−7 cm2·sec−1. Daraus ergeben sich die Molekulargewichte 138 000 bzw. 192000 und die Re…
Type V collagen-induced upregulation of capn2 (large subunit of m-calpain) gene expression and DNA fragmentation in 8701-BC breast cancer cells
2011
Abstract Type V collagen is known to be over-deposited in the stroma of ductal infiltrating carcinomas of the breast. When used as a substrate, type V collagen restrains growth and invasion, and affects gene expression of 8701-BC ductal infiltrating carcinomas cells. Here we supplement existing data by demonstrating type V collagen dependent upregulation of capn2 gene expression in 8701-BC cells through differential display-PCR and Western blot assays. Furthermore, we suggest that our data obtained by centrifugal sedimentation and electrophoresis strongly suggest a correlation between calpain overproduction and DNA fragmentation, since the incubation with calpain inhibitor partly reverts th…
1990
The determination of average molecular weights and the characterization of molecular weight distributions by the ratio of the weight- to number-average molecular weights Mw/Mn from sedimentation equilibrium in the ultracentrifuge are described. The essential measurement of the density profile of the mixed solvent is conducted according to Munk (Macromolecules15, 500 (1982)). Special evaluation of the polymer band in the equilibrium allowed to deduce from the observed concentration profile Mw and Mn of a series of poly(methyl methacrylate) samples and thus to characterize the molecular weight distribution of the samples.