Consulta: subjectFacets:"Flocculation"
Registros recuperados: 18
Data/hora: 07/06/2024 09:41:05

The dispersion of adhered marine bacteria by pyrophosphate and ultrasound prior to direct counting.
Provedor de dados: 5
Autores: Velji, M; Albright, L.
A technique has been investigated for dispersing adhered marine bacteria from various surfaces prior to direct counting. The bacterial cells were initially preserved and strengthened by use of 3.7% formaldehyde (v/v final concentration). Seawater samples were then treated with 0.001 M of tetrasodium pyrophosphate (final concentration), a sequestering and deflocculating agent. Surface sediment and kelp disc samples were treated with 0.01 M tetrasodium pyrophosphate (final concentration) after having been suspended in 0.44 M sodium chloride solution. These samples were incubated for 15-30 min. Subsequently, the samples were treated with ultrasound (100 W) for 30 to 45 s. This technique resulted in an even dispersion of most bacterial cells in the samples....
Tipo: Text
Palavras-chave: Bacteria; Microbiological analysis; Flocculation; Ultrasonics; Bacterial counters.
Ano: 1984
URL: http://archimer.ifremer.fr/doc/1984/acte-968.pdf

On the behavior of mud floc size distribution: model calibration and model behavior
Provedor de dados: 5
Autores: Mietta, Francesca; Chassagne, Claire; Verney, Romaric; Winterwerp, Johan C.
In this paper, we study a population balance equation (PBE) where flocs are distributed into classes according to their mass. Each class i contains i primary particles with mass m p and size L p. All differently sized flocs can aggregate, binary breakup into two equally sized flocs is used, and the floc’s fractal dimension is d 0 = 2, independently of their size. The collision efficiency is kept constant, and the collision frequency derived by Saffman and Turner (J Fluid Mech 1:16–30, 1956) is used. For the breakup rate, the formulation by Winterwerp (J Hydraul Eng Res 36(3):309–326, 1998), which accounts for the porosity of flocs, is used. We show that the mean floc size computed with the PBE varies with the shear rate as the Kolmogorov microscale, as...
Tipo: Text
Palavras-chave: Flocculation; Population balance equation; Discretization into classes; Kaolinite; Natural mud; Zeta-Potential.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00028/13875/11033.pdf

Etude au microscope electronique a balayage des relations entre bacteries et matieres en suspension en milieu marin
Provedor de dados: 5
Autores: Cormier, M; Bassoulet, P; Pommepuy, Monique.
Near outfall areas numerous bacteria appear associated to colloidal organic matter present in littoral sea water. Arrangements into colonies are shown. Surface structures are observed which allow bacteria's attachment each to other and to organic matter.
Tipo: Text
Palavras-chave: Bacteria; Outfalls; Electron microscopy; Flocculation; Colloids; Adhesion; Suspended particulate matter.
Ano: 1984
URL: http://archimer.ifremer.fr/doc/1984/acte-966.pdf

In situ video and diffraction analysis of marine particles
Provedor de dados: 5
Autores: Lunven, Michel; Gentien, Patrick; Kononen, K; Le Gall, Erwan; Danielou, Marie-madeleine.
A design for a new underwater video-system to detect and observe suspended particles is presented. Particles are collected and isolated in a rectangular box where they are highly illuminated by a white light plane. The total field of view is determined. The camera, equipped with a remote controlled zoom, can resolve particles sizes ranging from 25 mum to several millimetres. Real-time image analyses are therefore performed. Particle counts and size spectra are calculated and displayed. Total light intensity scattered by the illuminated particles is closely related to the back-scattering values determined by an optical back-scatter sensor. A particle size analyser using diffraction analysis is associated to this video-system on a custom profiler....
Tipo: Text
Palavras-chave: Image analysis; Fine scale distribution; Flocculation; Suspended matter; In situ measurement.
Ano: 2003
URL: https://archimer.ifremer.fr/doc/2003/publication-504.pdf

Influence of     Crepidula fornicata     on suspended particle dynamics in coastal systems: a mesocosm experimental study
Provedor de dados: 5
Autores: Grasso, Florent; Carlier, Antoine; Cugier, Philippe; Verney, Romaric; Marzloff, Martin.
In coastal environments, strong feedback can exist between benthic fauna and sediment dynamics. Benthic populations can modify sediment dynamics through biofiltration and bioturbation, while hydro- and sediment dynamics directly determine local environmental conditions for benthic organisms. However, these complex feedbacks are difficult to study in situ. Here, we carried out mesocosm experiments to characterize the effects of a benthic species (the gastropod Crepidula fornicata) on mud dynamics under hydrodynamic conditions representative of their natural habitat. Different experimental tests related to the inclusion (or not) of dead or live crepidula reveal that biofiltration can increase particle settling up to 40%. Flocculation, which is strengthened...
Tipo: Text
Palavras-chave: Laboratory experiments; Coastal processes; Physical-biological interactions; Benthic engineer species; Mud settling; Flocculation; Biofiltration; Organic matter.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00662/77403/79043.pdf

Dynamique des matières en suspension en mer cotière : caractérisation, quantification et interactions sédiments/matière organique
Provedor de dados: 5
Autores: Chapalain, Marion.
The knowledge of suspended particulate matter (SPM) and turbidity dynamics in coastal waters is essential for studying marine ecosystems. Flocculation/deflocculation processes are crucial mechanisms controlling the dynamics of SPM physical characteristics and thus, the fate of these SPM in the environment. This PhD thesis focuses on the SPM characteristics and their dynamics in coastal waters, from tidal to annual scales, in response to hydrodynamic, hydrological and biological forcing that take place at the interface between estuaries and coastal seas. To this end, optical and acoustic sensors were deployed in situ through 6 field campaigns in 2016, in order to characterize and quantify SPM in the water column, near the mouth of the Seine estuary...
Tipo: Text
Palavras-chave: Matière en suspension (MES); Floculation; Matière organique; Distribution en classe de taille; Dimension fractale; Capteurs optiques et acoustiques; Baie de Seine; Suspended particulate matter (SPM); Flocculation; Organic matter; Particle size distribution; Fractal dimension; Optical and acoustic sensors; Seine Bay.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00500/61155/64591.pdf

Production of microalgal concentrates by flocculation and their assessment as aquaculture feeds
Provedor de dados: 5
Autores: Knuckey, R; Brown, M; Robert, Rene; Frampton, D.
A novel technique was developed for the flocculation of marine microalgae commonly used in aquaculture. The process entailed an adjustment of pH of culture to between 10 and 10.6 using NaOH, followed by addition of a non-ionic polymer Magnafloc LT-25 to a final concentration of 0.5 mg L&amp;#8722;1. The ensuing flocculate was harvested, and neutralised giving a final concentration factor of between 200- and 800-fold. This process was successfully applied to harvest cells of Chaetoceros calcitrans, C. muelleri, Thalassiosira pseudonana, Attheya septentrionalis, Nitzschia closterium, Skeletonema sp., Tetraselmis suecica and Rhodomonas salina, with efficiencies &amp;#8805;80%. The process was rapid, simple and inexpensive, and relatively cost neutral with...
Tipo: Text
Palavras-chave: Chaetoceros; Thalassiosira; Flocculation; Concentrate; Bivalve; Algal paste.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-1820.pdf

Behaviour of a floc population during a tidal cycle: laboratory experiments and numerical modelling
Provedor de dados: 5
Autores: Verney, Romaric; Lafite, Robert; Brun-cottan, Jean Claude; Le Hir, Pierre.
An approach combining laboratory experiments and numerical modelling was used to investigate the behaviour of a floc population during an idealized tidal cycle. The experiment was conducted on suspended sediments at a concentration of 93 mg l−1 collected in the field. It was based on a jar test device to reproduce tidal-induced turbulence and coupled with a CCD camera system and image post-processing software to monitor floc size distribution. At the same time, a 0D size-class based aggregation/fragmentation model (FLOCMOD) was developed to simulate changes in the floc population over the tidal cycle. Experimental results revealed strong variability of the behaviour of microfloc and macrofloc populations with respect to the varying shear rates observed in...
Tipo: Text
Palavras-chave: Flocculation; Tidal cycle; Laboratory experiment; FLOCMOD; OD model; Sensitivity analysis; Optimization.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00027/13846/11020.pdf

Flocculation Potential of Estuarine Particles: The Importance of Environmental Factors and of the Spatial and Seasonal Variability of Suspended Particulate Matter
Provedor de dados: 5
Autores: Verney, Romaric; Lafite, Robert; Brun-cottan, Jean-claude.
Estuarine systems are complex environments where seasonal and spatial variations occur in concentrations of suspended particulate matter, in primary constituents, and in organic matter content. This study investigated in the laboratory the flocculation potential of estuarine-suspended particulate matter throughout the year in order to better identify the controlling factors and their hierarchy. Kinetic experiments were performed in the lab with a "video in lab" device, based on a jar test technique, using suspended sediments sampled every 2 months over a 14-month period at three stations in the Seine estuary (France). These sampling stations are representative of (1) the upper estuary, dominated by freshwater, and (2) the middle estuary, characterized by a...
Tipo: Text
Palavras-chave: Seine estuary (France); Kolmogorov microscale; Diatom bloom; Floc structure; Cohesive sediment; Flocculation.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6631.pdf

Geometry, fractal dimension and settling velocity of flocs during flooding conditions in the Rhône ROFI
Provedor de dados: 5
Autores: Many, G; Durrieu De Madron, Xavier; Verney, Romaric; Bourrin, F; Renosh, Pr; Jourdin, F; Gangloff, A.
Regions Of Freshwater Influence (ROFI) are of particular interest in a source-to-sink approach in terms of sediment advection, settling, and deposition in the coastal zone. An experiment was carried out in the ROFI of the Rhône River in February 2016 to describe the properties of suspended particulate matter (SPM) during a flood event. A digital holographic camera (LISST-HOLO, 20–2000 μm) was used to estimate the variability of fine sediment floc properties (size, nature and shape) formed in the Rhône mouth. An automatic image toolbox was developed to classify the different constituents of the SPM (as diatoms, bubbles and flocs) and to describe the diversity of floc shapes existing in the material in suspension. We estimated the fractal dimension (DF3D),...
Tipo: Text
Palavras-chave: Flocculation; Fractal dimension; Settling velocity; ROFI; Rhone.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00478/58952/61540.pdf

Mejoramiento de la floculación de cepas de levadura cervecera
Provedor de dados: 20
Autores: Abreu, J.; González, J.; Rodríguez, Y.
Las cepas de levadura originales usadas en las cervecerías cubanas: Saccharomyces uvarum U-57,  Saccharomyces uvarum Budvar y  Saccharomyces cerevisiae F-26, se probaron en columnas EBC a 10 ºC durante 7 días, atendiendo a sus propiedades tecnológicas fundamentales: crecimiento, floculación, sedimentación, atenuación, producción de alcohol y eficiencia fermentativa. La floculación de las cepas se estudió a través de aislamientos celulares y valoración morfológica. Los cultivos de levaduras originales y aislados se evaluaron comparativamente en la fermentación, con relación a la capacidad de floculación, concentración de células en suspensión y demás propiedades. Las cepas de levaduras cerveceras originales y aisladas, S. uvarum U-57 y S. uvarum Budvar y...
Tipo: Journal Contribution
Palavras-chave: Production (industrial); Appropriate technology; Flocculation.
Ano: 2008
URL: http://hdl.handle.net/1834/4891

Water-dispersible clay in soils treated with sewage sludge
Provedor de dados: 90
Autores: Tavares Filho,João; Barbosa,Graziela Moraes de Césare; Ribon,Adriana Aparecida.
A by-product of Wastewater Treatment Stations is sewage sludge. By treatment and processing, the sludge is made suitable for rational and environmentally safe use in agriculture. The aim of this study was to assess the influence of different doses of limed sewage sludge (50 %) on clay dispersion in soil samples with different textures (clayey and medium). The study was conducted with soil samples collected from native forest, on a Red Latosol (Brazilian classification: Latossolo Vermelho distroférrico) loamy soil in Londrina (PR) and a Red-Yellow Latosol (BC: Latossolo Vermelho-Amarelo distrófico) medium texture soil in Jaguapitã (PR). Pots were filled with 3 kg of air-dried fine earth and kept in greenhouse. The experiment was arranged in a randomized...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Biosolids; Flocculation; PZC; ΔpH; Organic matter.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832010000500005

Flocculation of fine fluorite particles with Corynebacterium xerosis
Provedor de dados: 59
Autores: Haas,Sandra R.; Nascimento,Fábio R.; Schneider,Ivo André H.; Gaylarde,Christine.
The treatment of fine particles dispersed in liquids is common in several industries and especially important in mineral processing. The efficiency of settling operations can be substantially increased by flocculation. The aim of this work was to study the flocculation of fine fluorite particles by the bacterium Corynebacterium xerosis. Flocculation tests, microelectrophoresis measurements and optical microscopy were used to evaluate flocculation. The results showed that C. xerosis cells adhere to the fluorite surfaces promoting the aggregation of the particles. High quality flocs can be obtained rapidly at pH 7.0 using a cell concentration of 40 mg/l, considerably lower than previously reported in the literature. The results are discussed with reference...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Adhesion; Corynebacterium xerosis; Flocculation; Fluorite.
Ano: 1999
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37141999000300007

Charge sparsity: An index to quantify cation effects on clay dispersion in soils
Provedor de dados: 63
Autores: Melo,Thadeu Rodrigues de; Machado,Wesley; Tavares Filho,João.
ABSTRACT: Few approaches have been developed to measure the isolated effect of exchangeable cations on clay dispersion in soils. In this study, the charge sparsity (CS) index was proposed using the ratio between the cations hydrated ionic radius and valence. The index capacity to measure cation effects on clay dispersion in soils was also evaluated. Three Ferralsols, sampled at different sites in Paraná State, Brazil, were homoionized with Ca2+, Mg2+, K+, or Na+ prior to evaluation of the clay dispersion degree. Published independent data for two soils and clays were also used. We tested the capacity of CS and II, the latter proposed by Marchuck and Rengasamy (2011), to predict clay dispersion in soils. The CS predicted the dispersion degree more...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Colloids; Electrical double layer; Aggregation; Flocculation; Zeta potential.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162020000101400

Recovery of Bacillus sphaericus spores by flocculation/sedimentation and flotation
Provedor de dados: 52
Autores: Luna,Christine Lamenha; Lopes,Carlos Edison; Massarani,Giulio.
The aim of this work was use flocculation/sedimentation and flotation for recovery of spores of the Bacillus sphaericus. Microorganism was produced batchwise using culture medium based skimmed milk, corn steep liquor and mineral salts. The best results of flocculation were obtained using CaCl2.2H2O, FeCl3.6H2O, Al2(SO4)3 and tannin as flocculating agents, with optimal flocculation concentrations of 1,500, 3,000, 2,000 and 1,700ppm, respectively. Flocculent suspensions were characterized based on floc diameter and density. Settling tests were performed in batch at different concentrations of the cellular suspensions and revealed high recovery of the solids in suspension in all cases. Flotation tests were accomplished using a mechanical agitated flotation...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bacillus sphaericus; Flocculation; Sedimentation; Flotation.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132005000400008

Tratamento biológico de efluentes de indústrias de papel após floculação e coagulação com sais de alumínio e polieletrólitos naturais
Provedor de dados: 52
Autores: Reis,Edson M. dos; Nozaki,Jorge.
The flocculation and sedimentation of recalcitrant organic compounds of high molecular weight using natural polyelectrolytes, extracted from the cactus Cereus peruvianus and Opuntia ficus indica, have been studied. Organic compounds of high molecular weight from effluents of paper and pulp industries are difficult for biological degradation. However, using a mixture of aluminum salts and natural polyelectrolytes, the aggregation and settling properties of recalcitrant organics were increased if compared with conventional methods of wastewater treatment using only aluminum or iron sulfate. After flocculation, sedimentation, and filtration, the effluent was submitted to biological degradation by activated sludge process. The main advantages of using a...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Flocculation; Natural polyelectrolytes; Biological degradation; Activated sludge process; Paper and pulp effluents.
Ano: 2000
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132000000100016

Flocculation of fine fluorite particles with Corynebacterium xerosis and commercial long chain polymers
Provedor de dados: 58
Autores: Rigo,Lisandra N.; Pinto,Angela Maria; Denardin,Norimar D'Avila; Schneider,Ivo André H.
This work aimed to study, comparatively, the flocculation of fluorite particles with Corynebacterium xerosis cells and three commercial long chain polymers. Best flocculation results were obtained with cells of C. xerosis and with an anionic polyacrylamide. Both were effective in solids removal and water clarification, although flocculation with C. xerosis cells requires a higher dosage of reagent per mass unit of processed ore.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Corynebacterium xerosis; Flocculation; Fluorite; Polymers.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822002000400010

Evaluation of skimmed milk flocculation method for virus recovery from tomatoes
Provedor de dados: 58
Autores: Melgaço,Fabiana Gil; Corrêa,Adriana Abreu; Ganime,Ana Carolina; Brandão,Marcelo Luiz Lima; Medeiros,Valéria de Mello; Rosas,Carla de Oliveira; Lopes,Silvia Maria dos Reis; Miagostovich,Marize Pereira.
Abstract This study aimed to evaluate the elution-concentration methodology based on skimmed milk flocculation from three varieties of tomatoes (Solanum lycopersicum L. [globe], Solanum lycopersicum var. cerasiforme [cherry] and hybrid cocktail [grape tomato]) for further monitoring of field samples. Spiking experiments were performed to determine the success rate and efficiency recovery of human norovirus (NoV) genogroup II, norovirus murine-1 (MNV-1) used as sample process control virus and human adenovirus (HAdV). Mean values of 18.8%, 2.8% and 44.0% were observed for NoV GII, MNV-1 and HAdV, respectively with differences according to the types of tomatoes, with lower efficiency for cherry tomatoes. Analysis of 90 samples, obtained at commercial...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Adenovirus; Flocculation; Murine norovirus-1; Norovirus; Tomato.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822018000500034