975 resultados para quick coagulation


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Aerosol size distributions from 6 to 700 nm were measured simultaneously at an urban background site and a roadside station in Oporto. The particle number concentration was higher at the traffic exposed site, where up to 90% of the size spectrum was dominated by the nucleation mode. Larger aerosol mode diameters were observed in the urban background site possibly due to the coagulation processes or uptake of gases during transport. Factor analysis has shown that road traffic and the neighbour stationary sources localised upwind affect the urban area thought intra-regional pollutant transport.

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The aim of this study was to verify the influence of the apparent molecular size of aquatic humic substances on the effectiveness of coagulation with ferric chloride. Coagulation-filtration tests using jar test and bench-scale sand filters were carried out on samples of water with true color of approximately 100 Hazen units, prepared with aquatic humic substances of different molecular sizes (F1: < 0.45 µm, F2: 100 kDa - 0.45 µm, F3: 30 - 100 kDa and F4': < 30 kDa). For the water samples with lower apparent molecular size fractions, greater dosages of coagulant was needed to remove the color around 5.0 Hanzen units, mainly because these water samples contain higher concentrations of fulvic acids, which exhibited a larger number of negatively-charged groups.

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This review attempts to provide an updated overview of the Quick, Easy, Cheap, Effective, Ruged and Safe (QuEChERS) multiresidue extraction method, that involves initial extraction in acetonitrile, an extraction/partition step after the addition of salt, and a cleanup step utilizing dispersive solid phase extraction. QuEChERS method is nowadays the most applied extraction method for the determination of pesticide residues in food samples, providing acceptable recoveries for acidic, neutral and basic pesticides. Several applications for various food matrices (fruits, vegetables, cereals and others) in combination with chromatographic mass spectrometry analysis were presented.

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This paper describes a homemade autosampler for flow injection analysis (FIA), constructed with two step motors from old floppy disk drives (5¼-inch). The autosampler was connected to a computer through the parallel port and the sampling process was controlled by software in Quick Basic. The performance of the system was assessed by the determination of ammonium, based on the gaseous diffusion into a bromocresol purple solution, following the spectrophotometric determination of change in absorbance. The easy and simple construction is the main characteristics of this equipment and analytical results with RSD lower than 1% were obtained.

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In order to investigate the action of the flocculating agents Panfloc and Panclar a full factorial design 2³ and a Central Composite design 2² were carried out. The control variables were the flocculant concentration, pH and temperature. The response variables were phenolic compounds reduction and spectral area reduction. The best conditions of treatment was hydrolyzate at pH 9 for both coagulants, but the use of Panfloc was more effective in the phenolic compounds reduction (73.9%) and spectral area reduction (65.8%).

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The main objective was to study the treatment of wastewater generated by the oil industry. This work consisted of tests of electroflocculation with alternate current (AC), and chemical coagulation. The removal efficiencies of organic load were evaluated by the removal of oils and greases, color and turbidity. The parameters investigated were the change in alternate current frequency, the initial pH, the distance between electrodes, the applied potential and time lapse. From the results, one may conclude that the electroflocculation process is potential applicability to the effluent studied, while chemical coagulation was not successful.

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This paper regards the implementation of the QuEChERS method for the analysis by GC-FPD of 53 different pesticides from the organophosphate class, in whole UHT and pasteurized milk. Selectivity, linearity, repeatability, recovery and limits of detection and quantification were evaluated. Of all pesticide recoveries, 51 were considered satisfactory since the values ranged from 70 to 120% with RSD < 20%. The quantification limits ranged from 0.005 to 0.4 mg kg-1. The QuEChERS method was suitable for determination of 52 pesticides, presenting several advantages - quick, cheap, easy, effective, rugged and safe - with regard to other traditional methodologies.

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Shadow masks are used in manufacturing processes for electro-optic devices to transfer patterns with different shapes and dimensions. For fabrication of organic based devices, shadow masks should be made of materials stable against organic solvents, high temperature, and robust, remaining unchanged after multiple cycles of use and fixation. Thus, stainless steel is suitable for shadow masks. A simple, cheap and quick method of obtaining shadow masks by electrochemical corrosion of stainless steel is reported. The shadow mask was used to evaporate cathode material to obtain an organic light emitting diode with active area of 9 mm². This device exhibited a turn-on voltage of 5 V and luminance of 14 cd/m².

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Proteases catalyze the hydrolysis of peptide bonds of proteins and peptides to produce smaller peptides and free amino acids. These enzymes are involved in physiologic processes such as blood coagulation and cellular death, and are related to life cycle of several viruses, such as hepatitis C, dengue, and AIDS. These features make most of proteases very important therapeutic targets for new pharmaceutical compounds. The development of peptidemimetics with improved pharmacokinetic properties is driving extensive research in the field of viral protease inhibitors. The present paper aims to highlight the design and synthesis of peptidemimetics that are able to inhibit viral proteases related to hepatitis C, dengue, and AIDS.

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In this work, the efficiency of clarification treatment (coagulation, flocculation and sedimentation) with polyaluminum chloride (PAC) and aluminum sulfate (SA) as coagulants was evaluated in the removal of 7 microcontaminants (diclofenac - DCF, sulfamethoxazole - SMX, ethinylestradiol - EE2, bisphenol-A - BPA, estradiol - E2, estrone - E1 and estriol - E3) in water of low and high turbidity. The clarification treatment led to poor removal rates (40% at most) for all microcontaminants except SMX which exhibited intermediate removal efficiency (67 to 70%). Overall, PAC application yielded better performance compared to SA.

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This work was aimed at evaluating the possibility of using bromophenol blue as an indicator for detecting the presence of Sclerotinia sclerotiorum in the seeds of dry-beans (Phaseolus vulgaris) and soybean (Glycine max), through incubation of the seeds on an agar medium and "blotter" substrates. The seeds were artificially inoculated with four S. sclerotiorum isolates, plated on the agar medium, named Neon, and on modified Neon agar media all incubated at 14 and 20 ºC for seven days in the dark. Half of the seeds inoculated were surface desinfested prior to plating on the medium. The seeds showing change of colour in the medium, from blue to light yellow, as well as formation of typical mycelium and sclerotia in some cases, were considered to be infected or contaminated by S. sclerotiorum. The two incubation temperatures compared did not show significant (P<0.05) differences in detection level for most of the isolates tested on the different media. According to results obtained in this study, the Neon agar medium with incubation at 14 or 20 ºC has proved to be a reliable and quick method for the detection of S. sclerotiorum mycelium in naturally infected seeds of bean and soybean.

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Tämä diplomityö käsittelee toiminnanohjausjärjestelmän käyttöönottoa ja käyttöönoton kriittisten menestystekijöiden toteutumista. Työn tavoitteena oli tutkia kirjallisuudessa esiintyviä käyttöönoton kriittisiä menestystekijöitä ja verrata niitä Pyrollsack Oy:n käyttöönottoprosessista saatuihin kokemuksiin. Tuloksena voidaan havaita menestystekijät sekä esittää parannusehdotuksia havaittuihin heikkouksiin. Käyttöönottoprojektissa vahvuuksina nähtiin huolellinen valmistautuminen projektiin, uuden toiminnanohjausjärjestelmän strategisen merkityksen ymmärtäminen, nopea päätöksenteko sekä operatiivisen käyttöönoton ajoitus ja vaiheistus. Heikkouksina nähtiin liiallinen viive suunnittelun ja toteutuksen välillä, riittämättömät henkilöresurssit, ohjausryhmän toimimattomuus, viestintä, muutosjohtaminen, puutteellinen tietojen konversio, koulutus sekä toimittajan puutteellinen ymmärrys tehdystä vaatimusmäärittelystä. Käyttöönotto tulisi nähdä laajana projektina, joka koskee koko organisaatiota. Pienissä ja keskisuurissa yrityksissä erityistä huomiota tulee kiinnittää henkilöresurssien riittävyyteen. Uusi toiminnanohjausjärjestelmä saattaa aiheuttaa hetkellisen taantuman toiminnan sujuvuudessa. Toiminnanohjausjärjestelmän hyödyt toiminnalle ovat vaikeasti mitattavissa ja usein positiiviset vaikutukset havaitaan vasta vuosien päästä.

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Supermatrix on Finnet-liitto ry:n jäsenyritysten hanke, joka tuo nopeiden valokuituyhteyksien avulla erilaisia sähköisiä palveluita kuluttajien koteihin ja yritysten toimipisteisiin. Näitä palveluita ovat mm. virtualisoidut henkilö-kohtaiset tietokoneet, tiedon tallennuspalvelut ja multimediasisältö, kuten teräväpiirtotelevisio. Tässä diplomityössä arvioidaan Supermatrixin palveluiden toteutumis-mahdollisuuksia sekä teknologian, että markkinoiden kannalta. Työn tarkoituksena oli myös laskea virtualisoitujen tietokoneiden avulla tuotetun työpöytäpalvelun tuotantokustannus. Kustannuslaskentaa varten testattiin useiden valmistajien teknologioita, ja parhaimmista vaihtoehdoista laskettiin tuotantokustannukset. Tulevia Supermatrix-operaattoreita varten kehitettiin työkalu, jolla työpöytäpalvelun vaatimien investointien kannattavuus saadaan nopeasti selville. Tuotantohintojen laskelmat osoittavat, että työpöytäpalvelua on taloudelli-sesti mahdollista tuottaa luomaan lisäarvoa nopeille laajakaistayhteyksille. Yrityksissä työpöytien virtualisointi on jo tämän päivän teknologiaa, mutta kuluttaja-asiakkaiden innostuminen palvelusta vaatii uuden markkinan luomisen. Uhkana on, että kuluttajien ostokäyttäytymisen muuttaminen ei onnistu, koska Supermatrix ei tuota fyysisen tuotteen ostamisen tarjoamaa mielihyvää.

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A simple, quick and easy protocol was standardized for extraction of total DNA of the bacteria Xanthomonas axonopodis pv. phaseoli. The DNA obtained by this method had high quality and the quantity was enough for the Random Amplified Polymorphic DNA (RAPD) reactions with random primers, and Polymerase Chain Reaction (PCR) with primers of the hypersensitivity and pathogenicity gene (hrp). The DNA obtained was free of contamination by proteins or carbohydrates. The ratio 260nm/380nm of the DNA extracted ranged from 1.7 to 1.8. The hrp gene cluster is required by bacterial plant pathogen to produce symptoms on susceptible hosts and hypersensitive reaction on resistant hosts. This gene has been found in different bacteria as well as in Xanthomonas campestris pv. vesicatoria (9). The primers RST21 and RST22 (9) were used to amplify the hrp gene of nine different isolates of Xanthomonas axonopodis pv. phaseoli from Botucatu, São Paulo State, Brazil, and one isolate, "Davis". PCR amplified products were obtained in all isolates pathogenic to beans.

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Tämän tutkimuksen aiheena oli älypuhelimien käytettävyys naisnäkökulmasta. Aihe nousi esiin kesällä 2010 huomatessani, että älypuhelinmarkkinat ja –mainokset ovat hyvin pitkälle miehille suunnattuja. Etsiessäni materiaalia tuekseni tähän työhön huomasin, että sitä on erittäin vähän saatavilla. Tämän takia päätin toteuttaa työn käytettävyystestausprojektina. Projektin testiryhmä koostui naisista, jonka jäseniä pyydettiin suorittamaan valitsemillaan älypuhelimilla testitehtäviä. Testin jälkeen he vastasivat käytettävyystestauslomakkeissa olleisiin kysymyksiin, jotka koskivat testattuja älypuhelimia. Tutkimustuloksia analysoitaessa nousi esiin vähäinen tarve älypuhelimen ostamiseen. Tässä käytettävyystestausprojektissa lopputulos oli, että testaajat eivät kokeneet tarvetta ostaa vaikeasti hallittavaa sekä turhia sovelluksia sisältävää ja kallista älypuhelinta.