Dyeing of PA6.6 fibers - Effect of solvent and temperature on thermal properties

Dyeing fibers at low temperatures has many advantages such as savings in energy and avoiding alterations to the physical properties of the fibers being dyed or other fibers also present in blends, The problem of low temperature dyeing in synthetic fibers is that it difficults the dye diffusion into the fiber. In the case of polyamide 6.6 microfibers, by using benzyl alcohol as an auxiliary dyeing, it was shown that good diffusion was obtained for the dye exhaustion with metal complex dyes at temperatures more than 30°C below the normal dyeing temperature for the dye exhaustion with metal complex dyes. Using thermal analysis methods these results were shown to be caused by the lowering of the T g of the fiber when in the presence of benzyl alcohol.Fundação para a Ciência e a Tecnologia (FCT

Effect of temperature and surfactant on the control release of microencapsulated dye in lecithin liposomes. I

The objective of our work has been the microencapsulation of dyes with lecithin from soybean, with the formation of liposomes, as a substitute for synthetic auxiliaries so as to improve the quality of the effluent. Current scenarios promote the disintegration and leakage of the liposomes, such as, changes in temperature, pH and the use of surfactants. Since dyeing process is a mix of all these parameters, we pretended to study each one separately. Rhodamine 6G fluorescence is known to be concentration quenched through the formation of non-fluorescent dimmers and, additionally, through the energy transfer from rhodamine monomer to these dimmers (3). The temperature, the surfactant and pH induce a release of the encapsulated dye resulting in rhodamine dilution and consequently alterations in the dimerization/binding equilibrium. The experimental spectra indicate that rhodamine binds almost completely to liposomes. The decomposition of the rhodamine fluorescence spectra allowed us to determine the percentage of released dye during a simulated dyeing process, and allowed us to conclude that the dimerization process occurs mainly at the inner interfaces. The amount of dye released induced by temperature changes was greater in the presence of surfactant

Advances on the development of novel heterogeneous catalysts for transesterification of triglycerides in biodiesel

This paper describes experimental work done towards the search for more profitable and sustainable alternatives regarding biodiesel production, using heterogeneous catalysts instead of the conventional homogenous alkaline catalysts, such as NaOH, KOH or sodium methoxide, for the methanolysis reaction. This experimental work is a first stage on the development and optimization of new solid catalysts, able to produce biodiesel from vegetable oils. The heterogeneous catalytic process has many differences from the currently used in industry homogeneous process. The main advantage is that, it requires lower investment costs, since no need for separation steps of methanol/catalyst, biodiesel/catalyst and glycerine/catalyst. This work resulted in the selection of CaO and CaO modified with Li catalysts, which showed very good catalytic performances with high activity and stability. In fact FAME yields higher than 92% were observed in two consecutive reaction batches without expensive intermediate reactivation procedures. Therefore, those catalysts appear to be suitable for biodiesel production

Argamassas com desempenho térmico melhorado

No contexto da investigação de novas tecnologias no domínio da conservação de energia surgem os “Phase Change Materials” (PCM) cuja principal característica é a mudança de fase (fase líquida para fase sólida e vice-versa) próximo à temperatura ambiente. O objecto desta comunicação é a divulgação de uma nova tecnologia, no domínio da técnica de aplicação de argamassas, que poderá ser utilizada na construção dos espaços interiores das construções. Os resultados dos ensaios efectuados mostraram que a incorporação de 25 % de PCM em peso, mantém as propriedades mecânicas das argamassas em níveis aceitáveis e é benéfica do ponto de vista térmico

Soybean oil transesterification for biodiesel production with micro-structured calcium oxide (CaO) from natural waste materials as a heterogeneous catalyst

In this study, micro-structured calcium oxide obtained from the calcination (850 degrees C for 3 h) of Gallus gallus domesticus (chicken) eggshells was used as a catalyst in the transesterification of soybean oil. This catalyst was characterized by Scanning Electron Spectroscopy (SEM) methods. The structure of the obtained CaO showed several agglomerates of white granular solids with a non-regular and unsymmetrical shape. In terms of calcium oxide catalytic activity, three different catalyst loadings (1%wt, 3%wt, and 5%wt) were tested for the same reaction conditions, resulting in transesterification yields of 77.27%wt, 84.53%wt, and 85.83%wt respectively. The results were compared to the current literature, and whilst they were lower, they were promising, allowing us to conclude that the tendency of yield improvement for this reaction, when the size range of catalyst particles is to be reduced to a nano scale, can be verified.info:eu-repo/semantics/publishedVersio

Poly(vinylidene fluoride-trifluoroethylene) (72/28) interconnected porous membranes obtained by crystallization from solution

Electroactive macroporous poly[(vinylidene fluoride)-co-trifluoroethylene] mambranes membranes have been processed by solvent evaporation at room temperature with different polymer/solvent concentrations. The pore architecture consists of on an interconnected spherical pores and this morphology is independent of the membrane thickness. The porosity of the produced membranes increases from 57% for the higher polymer concentration in the polymer/solvent solution (15/85), up to 83% for the lowest polymer amount in the polymer/solvent solution. Far infrared and differential scanning calorimetry measurements reveal that the polymer crystallizes in the ferroelectric phase and the polymer/solvent ratio does n’t not changes the Curie transition and the melting temperature of the polymer.The authors thank the Portuguese FCT (Grants PTDC/CTM/73030/2006, PTDC/CTM/69316/2006 and NANO/NMed-SD/0156/2007 and SFRH/BPD/63148/2009 (V.S.)) and the Spanish Ministry of Education and Ministry of Science and Innovation (Project No. MAT2007-66759-C03-01)

In Vitro Activity of Quaternary Ammonium Surfactants against Streptococcal, Chlamydial, and Gonococcal Infective Agents

Free PMC Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4879390/Quaternary ammonium compounds (QAC) are widely used, cheap, and chemically stable disinfectants and topical antiseptics with wide-spectrum antimicrobial activities. Within this group of compounds, we recently showed that there are significant differences between the pharmacodynamics of n-alkyl quaternary ammonium surfactants (QAS) with a short (C12) alkyl chain when in vitro toxicities toward bacterial and mammalian epithelial cells are compared. These differences result in an attractive therapeutic window that justifies studying short-chain QAS as prophylactics for sexually transmitted infections (STI) and perinatal vertically transmitted urogenital infections (UGI). We have evaluated the antimicrobial activities of short-chain (C12) n-alkyl QAS against several STI and UGI pathogens as well as against commensal Lactobacillus species. Inhibition of infection of HeLa cells by Neisseria gonorrhoeae and Chlamydia trachomatis was studied at concentrations that were not toxic to the HeLa cells. We show that the pathogenic bacteria are much more susceptible to QAS toxic effects than the commensal vaginal flora and that QAS significantly attenuate the infectivity of N. gonorrhoeae and C. trachomatis without affecting the viability of epithelial cells of the vaginal mucosa. N-Dodecylpyridinium bromide (C12PB) was found to be the most effective QAS. Our results strongly suggest that short-chain (C12) n-alkyl pyridinium bromides and structurally similar compounds are promising microbicide candidates for topical application in the prophylaxis of STI and perinatal vertical transmission of UGI.This work, including the efforts of Otilia V. Vieira, was funded by FCT (PTDC/BIA-BCM/112138/2009). This work, including the efforts of Otilia V. Vieira, was funded by FCT (HMSP-ICT/0024/2010). This work, including the efforts of Otilia V. Vieira, was funded by FCT (iNOVA4Health - UID/Multi/04462/2013).info:eu-repo/semantics/publishedVersio

Interpretação do ensaio de carga dinâmico em estacas através de análises tipo CAPWAP

O objectivo deste trabalho é o de mostrar as potencialidades do ensaio de carga dinâmico, como método alternativo ou complementar ao ensaio de carga estático. Discutem-se os problemas associados ao método de interpretação dos registos obtidos no ensaio dinâmico, com base em análises tipo CAPWAP. Apresenta-se um estudo paramétrico discutindo a influência dos diversos parâmetros do modelo, nomeadamente, da rigidez de ponta, do deslocamento elástico limite e dos factores de amortecimento lateral e de ponta. Este modelo foi implementado num programa de cálculo com base nas equações originalmente propostas por Smith (1960).The aim of this work is to show the potentialities of the dynamic load test, as an alternative or a complementary method to the static load test. The problems associated to the interpretation method based on CAPWAP analyses are discussed. A parametric study is presented, discussing the influence of several parameters of the model, namely, the base rigidity, the quake and the lateral and base soil damping constant. This model was implemented in a computer code using the original equations proposed by Smith (1960).Sociedade Portuguesa de Geotecnia, Associação Brasileira de Mecânica dos Solos e Engenharia Geotécnica, Secção Autónoma de Engenharia Civil da Universidade de Aveir

Teste ergoespirométrico aplicado à prática do exercício físico: um estudo de revisão

A Ergoespirometria é um teste de esforço, onde se analisa as trocas gasosas e a variação da frequência cardíaca, com o incremento de intensidade. Nesse teste, é possível identificar dois marcadores fisiológicos, o limiar ventilatório e o ponto de compensação respiratória, marcadores estes de grande importância para identificação de intensidade e velocidade de treinamento. O presente trabalho tem como finalidade, a análise de um teste de esforço cardiopulmonar, para identificação desses dois marcadores, o limiar ventilatório e o ponto de compensação respiratória, para treinamento individualizado. Estudo de revisão narrativa, a qual se buscou artigos científicos, consensos e diretrizes publicadas em bases de dados da internet como a plataforma Lilacs e Bireme. O teste apresenta respostas importantes no que tange a prescrição do exercício físico. Com a identificação dos marcadores fisiológicos é possível identificar e quantificar a intensidade de treinamento para alcance mais pontual do objetivo almejado