Improvement of bagasse fiber–cement composites by addition of bacterial nanocellulose: an inverse gas chromatography study

The design of green fiber-reinforced nanocomposites with enhanced properties and dura bility has attracted attention from scientists. The present study aims to investigate the potential of bacterial nanocellulose (BNC) as a green additive for fiber–cement composites. Inverse gas chromatography (IGC) was used to evaluate the influence of incorpo ration of BNC as powder or gel, or coated onto the bagasse fibers, on the fiber–cement composite (FCC) surface. The results indicated that BNC incorporation made the FCC surface more reactive, increasing the dispersive component of the surface energy. The most relevant effects were found for BNC incorporation as gel or coated on the fibers. Incorporation of BNC as gel resulted in a predominantly organic FCC surface with substantial decreased surface basicity (Ka/Kb ratio from 2.88 to 5.75). IGC also showed that FCC with BNC incorporated as gel was more susceptible to hydration. However, BNC coated on fibers prevented fiber mineralization, increasing the inorganic materi als at the surface, which caused an increase in the surface basicity (Ka/Kb ratio decrease to 2.00). These promising results could contribute to development of a new generation of green hybrid composites. The IGC technique enabled understanding of the physicochem ical changes that occur on deliberate introduction of nanosized bacterial cellulose into fiber–cement composites.info:eu-repo/semantics/publishedVersio

Bentonite from Porto Santo Island, Madeira Archipelago: surface properties studied by inverse gas chromatography

The present paper shows the importance of Inverse Gas Chromatography (IGC) for the determination of the surface properties of bentonites. These properties are dispersive surface energy, acid-base properties, surface heterogeneity, sorption isotherms, BET surface areas and heat of sorption, using different probe molecules. IGC can contribute to the interpretation, prediction and optimization of the studied materials’ properties. The paper focuses on two distinctive bentonite samples from Porto Santo Island, Madeira archipelago. In view of their potential value, achieved through their incorporation in products for dermopharmacy and dermocosmetics, particle size and particle surface properties are of fundamental importance.info:eu-repo/semantics/publishedVersio

Boletim agrometeorológico de 2009 para Tomé-Açu, PA.

bitstream/item/56810/1/DOC-377.pd

Avaliação de tolerância em diplóides de bananeira para Meloidogyne incognita.

A cultura da bananeira é suscetível a várias espécies de fitonematóides, principalmente, Radopholus similis, Pratylenchus coffeae e Meloidogyne spp. Dentre as estratégias de manejo de fitonematóides são prioritárias aquelas que reduzam custos, garantam a produção e não agridam o meio ambiente.Em paralelo aconteceram também os seguintes eventos: V Seminário de Pesquisa do Recôncavo da Bahia; V Seminário Estudantil de Pesquisa da UFRB; V Seminário da Pós-Graduação da UFRB; II Seminário Regional de Pesquisa da EBDA; 5ª Jornada Científica da Embrapa Mandioca e Fruticultura; VIII Seminário Estudantil de Pesquisa e Extensão da FAMAM; Semana de Ciência, Tecnologia e Inovação no Agronegócio; Fórum de Gestores de Iniciação Científica e Tecnológica da Bahia; II Simpósio Baiano de Defesa Agropecuária; I Semana de Educação Tutorial da UFRB

Boletim de agrometeorológico de 2009 para Belém, PA.

Boletim Agrometeorológico de 2009 para Belém, PA; Introdução; Metodologia; Aspectos Gerais do Clima; Informações Meteorológicas.bitstream/item/44214/1/Doc-371.pd

Avaliação do comportamento de diploides de bananeira em relação a Meloidogyne incognita.

A bananeira é suscetível a várias espécies de fitonematoides, principalmente Radopholus similis, Pratylenchus coffeae e Meloidogyne spp. Dentre as estratégias de manejo de fitonematoides são prioritárias aquelas que reduzam custos, garantam a produção e não agridam o meio ambiente.PDF. 118_11

Isolation and characterization of a lignin-like polymer of the cork of Quercus suber L

A lignin-like polymer was successfully extracted from the cork of Quercus suber L. using an organosolv-based technique. This material was characterized by elemental analysis, functional group analysis, nitrobenzene oxidation followed by HPLC analysis of the oxidation products, FTIR and liquid I3C NMR. The evidence thus obtained indicated that the extracted material was composed mainly of a lignin-like polymer covalently bound to residual aliphatic structures which are not present in common lignins and which have been assigned to suberin. The latter is likely to be attached to the oxygenated side chains of the phenolic polymer but bonding through the aromatic ring can also be envisaged. No residual carbohydrates were detected. The phenolic polymer, composed mainly of guaiacyl-type units and small amounts of syringyl-type units, had a low methoxy content and a high degree of condensation. This polymer showed the presence of a fraction containing CeCn units with n < 3 or even n < 2.info:eu-repo/semantics/publishedVersio

Cork suberin as an additive in offset lithographic printing inks

Suberin oligomers, isolated from cork (Quercus suber L.), were used as additives in ‘Waterless’ and vegetable-oil ink formulations, in the range of 2–10% w/w. The rheological behaviour of the suberin oligomers as well as of the inks, with and without suberin, were investigated as a function of temperature. It was shown that the addition of suberin induces a decrease of viscosity of both inks. The tack of pristine inks, suberin oligomers and their mixtures were determined at different temperatures: the variation of this parameter as a function of time provided information about the drying kinetics of these formulations. The tack of the ‘Waterless’ ink was found to increase with the introduction of suberin, whereas that of vegetable-oil based counterparts decreased. All the trends observed were interpreted in terms of the differences in composition between the two types of inks. Preliminary printing tests were carried out with the various suberin-containing inks.info:eu-repo/semantics/publishedVersio