688 research outputs found

    Developments in preparation and dyeing of CORONA discharged cellulosic materials

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    The preparation and dyeing of cellulosic fabrics hás important problems such as uniformity of aspect, cleaning efficiency, level of bleaching, conformity and fastness of colours, and ecological impact. Combination of preparation processes can give optimal solutions, regarding economy and ecology, especially if superior quality items are achieved in final products. In fact, high standards concerning whiteness, starch removal and hidrophilicity are considered a good basis for leveled, cleaner and intense dyeing. A better white basis, escellent hidrophilicity and enough removal of impurities are obtained if desizing is omitted and a CORONA discharge is made over dry grey material. Exhaustion dyeings with different classes of direct dyes show similar behavior concerning the positive influence of the discharge in the intensity of colours and their fastness. Good penetration of dyes in coronised cotton materials is assured and consequently a good fastness is abtained

    Quality improvement and shortcut of preparation of CORONA discharged cotton fabrics

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    Textile industry has an important impact in world economy and consequently on environmental quality of life. Textile processing uses huge amount of water, chemicals and energy and it is quite easy to conclude about the enormous meaning of pollution control and rationalization of energetic demands. CORONA treatment in the wet processing of cotton textile materials has a great potential concerning the improvement of all the operations included in it, namely in preparation, dyeing, printing or final finishing. Physical and chemical surface changes in cotton structure are noticed after CORONA discharge. The increase in oxidation potential and the creation of channels through cuticle are referred as responsible for the variation in cotton properties after plasmatic discharge, specially concerning absorption of water and treatment baths. Advantages as the use of less chemicals, namely alkalis, oxidants and other auxiliaries, the reduction of times and temperatures, less damages in the materials surely can have a strong impact in economical and ecological aspects of the process. Complete hidrophilization of cellulosic materials renders very easy the access of baths and consequently conditions to more efficient operations are found. Bleaching processes aim to give textile materials the adequate whiteness degree, the removal of sizing agents, the increase of hidrophility and cleaning by extraction of seeds, husks and waxes. The use of hydrogen peroxide in alkaline medium is a flexible and more ecological process when compared with methods based in chlorinated compounds. The present work concerns the study of half bleaching process when this operation is preceded by a CORONA discharge made on dry grey fabrics. The influence in the whiteness degree, hidrophility, starch removal and uniformity of properties of the cellulosic material after preparation is studied

    Petrografia e química mineral do Stock Granítico Serra do Barriga (Sobral, CE, nordeste do Brasil)

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    The Serra do Barriga Granitic Stock (SGSB), located at NNW of the Ceará, northeast of Brazil, presents faciological variation that permits commercial exploitation in four types of ornamental rocks: Rosa Iracema (RI), Rosa Olinda (RO), Branco Savana (BS) and White Crystal Quartz (BCQ). The aim of this paper is to investigate mineral association, chemical composition and classification of the main minerals phases, as well as genetic relationships among the granitic facies. Petrographic analyzes were made using thin section and analyzes of mineral chemistry through electron microprobe. Petrographic and mineral chemistry analyzes show that SBGS lithotypes varies from inequigranular to porphyritic syenogranites and monzogranites and different facies do not show significant differences in mineral composition, except for small variations of Or amount in K-feldspar. Potassium feldspar is orthoclase and plagioclase ranges from albite to oligoclase (Ab-Or- to Ab-Or). Biotite corresponds to annita to siderophyllite, while amphibole corresponds to iron-edenite. Post-magmatic or hydrothermal mineral transformations such as exsolution, potassification, albitization, chloritization, sericitization and neoformation of fluorite are common and control discoloration from the pink to the white facies (BS and BCQ). In the plagioclase of the white granites frequent sericitization occurs superimposed to the microclinization, with neoformation of fluorite. The whole data converge to the knowledge that all the facies were formed at the same magmatic event, being the syenogranites (RI, RO and BCQ) originated by an unique magma, followed by a new, more mafic magmatic pulse, represented by porphyritic monzogranite (RO).O Stock Granítico Serra do Barriga (SGSB), localizado a NNW do Ceará, nordeste do Brasil, apresenta variação faciológica que permite exploração comercial em quatro tipos de rochas ornamentais: Rosa Iracema (RI), Rosa Olinda (RO), Branco Savana (BS) e Branco Cristal Quartzo (BCQ). O objetivo deste trabalho é determinar a paragênese, a composição química e a classificação dos principais minerais, além das relações genéticas entre as fácies graníticas. Foram realizadas análises petrográficas, utilizando-se lâminas delgadas e análises de química mineral através de microssonda eletrônica. As análises petrográfica e de química mineral mostram que o SGSB varia de sienogranitos e monzogranitos inequigranulares a porfiríticos e não ocorrem diferenças significativas nas composições dos minerais entre as fácies, exceto ligeiras variações no teor de Or nos KF. O feldspato potássico é ortoclásio, o plagioclásio mostra transição de albita para oligoclásio. A biotita corresponde a annita com tendência a siderofilita, enquanto o anfibólio corresponde a ferro-edenita. As transformações minerais pós-magmáticas ou hidrotermais como exsolução, potassificação, albitização, cloritização, sericitização e neoformação de fluorita são comuns no SGSB e contribuem na “descoloração” das fácies rosas para as brancas. No plagioclásio dos granitos brancos ocorre frequente sericitização sobreposta à microclinização, com neoformação de fluorita. Todos os dados convergem para a ideia de que as fácies foram formadas por um mesmo evento magmático, sendo que os sienogranitos (RI, RO e BCQ) correspondem à faciologias originadas por um mesmo magma, seguido por um novo pulso magmático mais máfico, representado pelo monzogranito porfirítico (RO)

    Reutilização de águas residuais : modelação da adsorção de nutrientes no solo

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    O presente estudo incide na modelação da remoção de nutrientes presentes em águas residuais domésticas por adsorção no solo e na avaliação do risco de contaminação de aquíferos por parte destes. Nesse sentido, desenvolveu-se um modelo matemático e efectuou-se a determinação experimental dos parâmetros que caracterizam as isotérmicas de adsorção dos iões nitrato, fosfato e amónio. Os resultados experimentais indicaram que o solo tem principalmente carga iónica positiva, visto que os iões de carga contrária (tais como o nitrato e fosfato) foram os que principalmente adsorveram. Os resultados da simulação demonstraram que o fosfato é totalmente adsorvido e que a concentração de nitrato e amónio na água intersticial, após o período de um ano, é de 0.250 mg/L e 0.023 mg/L respectivamente, a 2 m de profundidade. Em relação ao exercício de simulação, estudouse o efeito de uma sobrecarga de nutrientes assim como a possibilidade de ocorrer saturação da coluna de solo. No caso de ocorrer uma sobrecarga de nutrientes no solo proveniente da descarga de água residual com uma concentração até quatro vezes superior ao valor médio, verificou-se que a concentração do ião amónio foi a mais afectada, aumentando de 27 % a uma profundidade de 2 m e ao fim de um ano. Finalmente, os parâmetros das isotérmicas de adsorção (segundo os modelos de Freundlich e Langmuir) foram sujeitos a uma análise de sensibilidade, tendo-se comprovado que o modelo desenvolvido é extremamente sensível à constante α da isotérmica de Freundlich

    Adenosine inhibits human astrocyte proliferation independently of adenosine receptor activation

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    Brain adenosine concentrations can reach micromolar concentrations in stressful situations such as stroke, neurodegenerative diseases or hypoxic regions of brain tumours. Adenosine can act by receptor-independent mechanism by reversing the reaction catalysed by S-adenosylhomocysteine (SAH) hydrolase, leading to SAH accumulation and inhibition of S-adenosylmethionine (SAM)-dependent methyltransferases. Astrocytes are essential in maintaining brain homeostasis but their pathological activation and uncontrolled proliferation plays a role in neurodegeneration and glioma. Adenosine can affect cell proliferation, but the effect of increased adenosine concentration on proliferation of astrocytes is not clarified and was addressed in present work. Human astrocytes (HA) were treated for 3 days with test drugs. Cell proliferation/viability was assessed by the MTT assay and by cell counting. Cell death was evaluated by assessing lactate dehydrogenase (LDH) release and by western blot analysis of αII-Spectrin cleavage. 30µM-Adenosine caused a 40%±3% (p < .05, n = 5) reduction in cell proliferation/viability, an effect reversed by 2U/ml-adenosine deaminase, but unchanged in the presence of antagonists of any of the adenosine receptors. Adenosine alone did not induce cell death. 100µM-Homocysteine alone caused 16%±3% (p < .05) decrease in HA proliferation. Combined action of adenosine and homocysteine decreased HA proliferation by 76%±4%, an effect higher (p < .05) than the sum of the effect of adenosine and homocysteine alone (56%±5%). The inhibitory effect of adenosine on HA proliferation/viability was mimicked by two adenosine kinase inhibitors and attenuated in the presence of folate (100µM) or SAM (50-100µM). The results suggest that adenosine reduces HA proliferation by a receptor-independent mechanism probably involving reversal of SAH hydrolase-catalysed reaction.info:eu-repo/semantics/acceptedVersio

    Atmospheric trends of CO and CH4 from extreme wildfires in Portugal using sentinel-5P TROPOMI level-2 data

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    PCIF/GFC/0078/2018 UIDB/00100/2020 UIDB/04085/2020 DL 57/2016Large forest fires have repeatedly affected Europe, in particular the Mediterranean countries. It is now crucial to continue the effort to feed the several layers of prediction models and understand how wildfire spreads in order to develop modern preventative and mitigation methods. The present study evaluates the performance of Sentinel 5-P TROPOMI for the monitoring of carbon monoxide (CO) and methane (CH4) during extreme fire events in Portugal, focusing on the Monchique (2018) and Vila de Rei/Mação (2019) wildfires, which devastated 27,154 ha and 9249 ha, respectively. The spatial distribution and trend of CO and CH4 prior to, during, and following the fire event were accessed and linked with in situ data in a qualitative and quantitative exploration. Large CO plumes were observed with CO columns exceeding 4.5 × 1018 and 6 × 1018 molecules/cm2 on 21 July 2019, and 7 August 2018, respectively. CO distribution profiles after consecutive digital processing steps showed the ability to follow CO fluctuations according to the fire spread. Furthermore, statistically significant differences were found between CO emissions inside and outside the burning area in both fire events. Finally, the CO2 estimated through CO column data presented an emission of 7.6 × 1019 molecules/cm2 for the uppermost emission day on 7 August 2018. Although CH4 monitoring is still unwavering to draw exact conclusions, the CO patterns during extreme fire events show promising and consistent data when compared with in situ data.publishersversionpublishe
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