Determinação quantitativa de corantes sulfurosos por potenciometria

Os corantes sulfurosos têm, desde o início da sua aplicação há mais de um século1, uma grande aplicação na Indústria Têxtil. De facto, embora quase todas as cores possam ser obtidas com corantes de outros tipos, a utilização de corantes sulfurosos para a obtenção de tons escuros (como o preto e o azul marinho) em fibras celulósicas continua a ser muito elevada2 . No entanto, devido à baixa solubilidade em água deste tipo de corantes, a sua quantificação é difícil. Associado a este problema encontram-se, ainda, várias dificuldades inerentes às técnicas analíticas. Nesta comunicação, é apresentada uma técnica de doseamento por titulação potenciométrica, baseada no método para doseamento de sulfuretos solúveis5. O procedimento consiste numa titulação potenciométrica por retorno, com sulfureto de sódio, após oxidação completa do corante com hexacianoferrato (III) de potássi

Détermination quantitative des colorants au soufre - dosage potentiométrique

Dans l’Industrie Textile, l’optimisation des procédés d’ennoblissement et la récupération et/ou réutilisation des produits chimiques sont des aspects importants à envisager. Plus précisément, il en est ainsi dans le cas des colorants et des produits auxiliaires utilisés en teinture.En particulier, les colorants au soufre et l’indigo posent de réels problèmes. De faible solubilité dans l'eau sous forme oxydée, leur l'application éxige l'utilisation d’un réducteur pour leur mise en solution dans le bain de teinture. Afin de surmonter ces difficultés, on propose ici une nouvelle méthode de dosage de colorants au soufre

Carbon Materials Derived from Cyano-Based IL@ZIF-8 Composites for CO2 Sorption Separation Systems

Additionally, this work was partially supported by the Asso- ciate Laboratory for Green Chemistry, LAQV, which is funded by national funds from FCT/MCTES (LA/P/00 08/2020) .The sorption capacity and selectivity of pre- and post-carbonized cyano-based metal-organic framework (MOF) composite materials (cyano-based IL@ZIF-8) were investigated for the first time. The influence of the ionic liquid (IL) loading and number of cyano groups in the IL anion on a materials gas sorption separation performance was studied. Sorption-desorption equilibrium isotherms of CO2, CH4, and N2 were measured at 303 K in the ZIF-8, cyano-based IL@ZIF-8 composites and their derived carbon materials. The IL loading did not significantly affect the gas uptake of the carbon materials, while for the composites its main contribution was on the increase of the selectivity. The number of cyano groups in the anion played a key role in the sorption capacity and selectivity performance as it directly affects the N content and textural properties. The carbon material obtained from ZIF-8 (C_ZIF-8) precursor showed the best sorption capacity for all gases, just being surpassed by the C_15%[C6MIM][B(CN)4]@ZIF-8 carbon up to 1 bar. In terms of selectivity performance, carbons based on [C6MIM][B(CN)4]@ZIF-8 composites revealed to be equally or more selective than C_ZIF-8, increasing up to 65% between 0 and 1 bar depending on the mixture. The composites produced and their respective carbons demonstrated a promising application as sorbents for post-combustion CO2 separation systems.publishersversionpublishe

Robinow Syndrome and otorhinolaryngoly - A case report

A Síndrome de Robinow é uma doença genética rara, com menos de 200 casos registados no mundo. Caracteriza-se pelo encurtamento mesomélico dos membros, baixa estatura, hipoplasia genital externa e uma fácies fetal. A sua transmissão pode ser autossómica recessiva ou dominante. Este artigo descreve o caso clínico de uma criança com diagnóstico pós-natal de Síndrome de Robinow esporádica autossómica dominante. Aos 12 anos de idade as anomalias otorrinolaringológicas incluíam a presença de uma bossa frontal, nariz curto com dorso largo, hipoplasia da maxila, fenda palatina corrigida e hipoacusia de condução bilateral. A Síndrome de Robinow é uma condição geneticamente heterogénea que pode ser facilmente diagnosticada na infância ou mesmo na avaliação pré-natal. O acompanhamento e intervenção otorrinolaringológicos podem melhorar o desenvolvimento e a qualidade de vida destas crianças.info:eu-repo/semantics/publishedVersio

Influência da raça na qualidade de couros caprinos

O estudo foi conduzido com o objetivo de avaliar a influência da raça na qualidade de couros caprinos. Foram utilizados cinco caprinos de cada uma das raças: Anglo Nubiana, Alpina e Saanen, com seis meses de idade. Os animais foram abatidos e as peles foram curtidas ao cromo e recurtidas com recurtente acrílico. Dos couros foram retiradas três amostras na posição paralela e três na perpendicular à linha dorsal para a avaliação da qualidade intrínseca de resistência à tração, ao rasgamento e ao lastômetro. As médias dos resultados foram comparadas pelo teste de Tukey ao nível de 5% de probabilidade. A raça não influenciou a resistência à distensão da superfície dos couros dos animais estudados no teste de lastômetro. As médias da resistência dos couros à tração foram maiores na posição longitudinal (P&#61500;0,05) para as três raças. Na posição longitudinal os couros dos caprinos Anglo Nubianos foram mais resistentes à tração (P<0,05), comparado com os couros das outras duas raças, que não apresentaram diferença entre si. A resistência dos couros ao rasgamento não sofreu influência da posição, porém na posição transversal os couros dos caprinos Anglo Nubianos foram mais resistentes (P<0,05), comparado com os couros das outras duas raças, que não apresentaram diferença entre si. A raça e a posição de retirada das amostras de couro influenciam a qualidade de couros caprinos

A_4-based neutrino masses with Majoron decaying dark matter

We propose an A_4 flavor-symmetric SU(3)xSU(2)xU(1) seesaw model where lepton number is broken spontaneously. A consistent two-zero texture pattern of neutrino masses and mixing emerges from the interplay of type-I and type-II seesaw contributions, with important phenomenological predictions. We show that, if the Majoron becomes massive, such seesaw scenario provides a viable candidate for decaying dark matter, consistent with cosmic microwave background lifetime constraints that follow from current WMAP observations. We also calculate the sub-leading one-loop-induced decay into photons which leads to a mono-energetic emission line that may be observed in future X-ray missions such as Xenia.Comment: 16 pages, 6 eps figures. Minor corrections. To appear in Phys. Rev.

Three new species of Neocamarosporium isolated from saline environments: N. aestuarinum sp. nov., N. endophyticum sp. nov. and N. halimiones sp. nov.

Neocamarosporium species are typically halotolerant, being commonly found in saline environments like saline water, hypersaline soils and especially in association with halophytes. Several isolates were obtained from saline water, dead leaves of the seaweed Zostera noltii and live tissues of the halophyte Halimione portulacoides. Phylogenetic analysis based on ITS sequence data placed these isolates into three clades within the genus Neocamarosporium distinct from the currently known species. Isolates from each clade showed clear differences in conidial morphology. Three new species N. aestuarinum sp. nov., N. endophyticum sp. nov. and N. halimiones sp. nov. are described and illustrated. Our results show that the salt marsh plant H. portulacoides harbours a high diversity of Neocamarosporium species.info:eu-repo/semantics/publishedVersio

Paramagnetic Ionic Liquid/Metal Organic Framework Composites for CO2/CH4 and CO2/N2 Separations

IF/01016/2014 SFRH/BD/139627/2018 PTDC/CTMCTM/30326/2017 PTDC/EQU-EQU/32050/2017 PTDC/FIS-MAC/28157/2017 UIDB/50006/2020 UIDP/50006/2020Global warming is arguably the biggest scientific challenge of the twenty-first century and its environmental consequences are already noticeable. To mitigate the emissions of greenhouse gases, particularly of CO2, there is an urgent need to design materials with improved adsorbent properties. Five different magnetic ionic liquids were impregnated into the metal–organic framework ZIF-8. The composites were produced by a direct-contact method, and their performance as sorbents for gas separation applications was studied. The impact of the ionic liquid anion on the sorption capacity and ideal CO2/CH4 and CO2/N2 selectivities were studied, focusing on understanding the influence of metal atom and ligand on the adsorbent properties. Reproducible methodology, along with rigorous characterization, were established to assess the impact of the ionic liquid on the performance of the composite materials. Results show that the ionic liquid was well-impregnated, and the ZIF-8 structure was maintained after ionic liquid impregnation. The produced composites were of microporous nature and were thermally stable. CO2, CH4, and N2 adsorption–desorption isotherms were obtained at 303 K and between 0 and 16 bar. The adsorption-desorption data of the composites were compared with that obtained for original ZIF-8. The general trend in composites is that the increased gas uptake per available pore volume compensates the pore volume loss. Adsorption data per unit mass showed that composites have reversible sorption, but inferior gas uptake at all pressure ranges. This is due to the observed total pore volume loss by the ionic liquid pore occupation/blockage. In most cases, composites showed superior selectivity performance at all pressure range. In particular, the composite [C4MIM]2[MnCl4]@ZIF-8 shows a different low-pressure selectivity trend from the original MOF, with a 33% increase in the CO2/N2 selectivity at 1 bar and 19% increase in the CO2/CH4 selectivity at 10 bar. This material shows potential for use in a post-combustion CO2 capture application that can contribute to greenhouse gas mitigation.publishersversionpublishe