Glass/polyvinyl chloride composites

This paper summarizes the results obtained in the use of plastisols of vinyl chloride homopolymer (PVC), obtained by the process of emulsion polymerization, as thermoplastic matrix in the production of composite pipes and in pipe repairing. Two processing techniques commonly used with thermosetting matrices were studied: filament winding and hand lay-up. The produced composite structures of PVC reinforced with glass fibres were subsequently subjected to tests in order to determine their mechanical properties. This paper concludes that it is possible to use the described technique for piping repairing with good results

Production and processing of pre-impregnated thermoplastic tapes by pultrusion and compression moulding

Although there is no doubt that composite materials are the future of lightweight structures and components, most of composites currently produced are made from thermoset polymers, which are not able to be recycled or reprocessed. In contrast, thermoplastic polymers offer the possibility to recycle and reprocess and when combined with a fibrous reinforcement, provide interesting mechanical properties. This work reviews the production of two thermoplastic preimpregnated materials in a tape form, one of which is produced on new prototype equipment developed in our laboratories. The method for the production of tape is described, and the prepregs presented here were subjected to two processing techniques. The first processing method, pultrusion, is an efficient and autonomous method to produce composite profiles, marking itself as a continuous and cost-effective way to produce these materials. Pultrusion bars were then subjected to heated compression moulding, a process that allows to obtain more complex-shaped parts. The second method, heated compression moulding, is a relatively simple process which was used to obtain composite laminates. The pultrusion bars and composite laminates were then subjected to mechanical testing to evaluate the levels of consolidation of the final material. A microscope testing was also carried out to analyse the dispersion of fibres and polymer, as well as the amount of voids present in the composite.Agência Nacional para a Inovação - ANI, Projeto ADD.CompFiber 6960

Serra da Estrela PDO cheese authentication: RAPD and SCAR approaches for identification of adulterant breed’s milk

Serra da Estrela cheese is a Protected Denomination of Origin (PDO) product and is perceived as a unique high-quality food, being the most famous Portuguese cheese and presenting high commercial value. It is legitimately manufactured from raw milk of the autochthonous sheep breed Serra da Estrela; however, the adulteration of production with cheaper and/or lowerquality milks from non-autochthones ovine breeds compromises the quality of the final product and undervalues the original PDO cheese. Considering that these fraudulent productions may lead to serious problems at both social and economic levels, it is urgent to develop low-cost, sensitive, fast and reliable analytical techniques that efficiently allow traceability of the breed origin of milk in Serra da Estrela PDO cheese. Here we describe a Randomly Amplified Polymorphic DNA (RAPD) method capable of efficient detection of adulterant breeds in milk mixtures, containing Serra da Estrela milk, used for fraudulent production of this cheese. Taking this into account, we suggest RAPD to be a valuable tool for identification of sheep breed in a first stage of milk authentication in dairy industry. Furthermore, considering the possible degradation of DNA during milk processing, Sequence Characterized Amplified Region (SCAR) markers were designed envisioning the detection of milk adulteration in processed dairy foods. RAPD-SCAR techniques have been here used, for the first time, to identify breed origin in milk samples, establishing its applicability for quality control on dairy industry, being capable of milk authentication in the final products. In this sense, our findings will play an important role on the valorization of not only the Serra da Estrela PDO cheese, but also on other high-quality dairy products prone to adulteration, contributing to the further development of the dairy industry.Project “Valor Queijo” (CENTRO-07-0202-FEDER-030372

Determination of frutooligosaccharides adsorption parameters using ion-exchange resins

Fructooligosaccharides (FOS) are non-digestible sugars that beneficially affect the host by stimulating the growth of specific bacteria in the colon. In large scale, FOS can be produced from sucrose by fermentation. The fermentative broth obtained from this process is a complex mixture of salts and sugars. These sugar mixtures include FOS, namely kestose (GF2), nystose (GF3) and fructo-furanosylnystose (GF4), but also fructose, glucose and sucrose that must be separated. The major challenge when designing the downstream separation process is the choice of an efficient ion-exchange resin. Therefore, adsorption isotherms of the different compounds on a mixture are an important parameter to consider when selecting the resin. Moreover, salts and other sugars present in the mixture will influence the adsorption. In view of this, in the present work adsorption isotherms of FOS, both from fermentative broths and pure mixtures, were determined for several poly(styrene-co-divinylbenzene) commercial resins in the sodium and calcium forms. A static adsorption-desorption method was used to determine the equilibrium adsorptions. The adsorption isotherms for FOS were appropriately fitted using linear regression models. Since FOS separation is mainly based on size exclusion, GF2 was found to be the most adsorbed sugar in all resins, followed by GF3 and finally GF4. Results demonstrated that there are no significant differences between the adsorption of a pure mixture of FOS and a fermentative broth using the studied commercial calcium resins. However, this was not observed for the sodium form resin. In this later case, the sugars from the fermentative broths were found to be more adsorbed than from the pure mixtures. Results gathered in this study clearly demonstrated the importance of determining the adsorption parameters using real fermentative broths instead of pure mixtures, as the presence of other sugars and salts can influence in the adsorption

Efeito do duplo envelhecimento no módulo de elasticidade da liga Ti-12Mo-13Nb

Ligas de Ti do tipo b estão sendo muito estudadas para aplicação em dispositivos biomédicos por apresentarem um balanço de vantagens em relação às outras ligas de Ti. Contudo, para um material ser utilizado como implante ortopédico é necessário um balanço entre alta resistência e baixo módulo de elasticidade. Várias microestruturas podem ser obtidas por diferentes tratamentos de envelhecimento os quais influenciam várias propriedades das ligas e, portanto, um satisfatório tratamento de envelhecimento poderá resultar num melhor balanço entre baixo módulo de elasticidade e alta resistência. Há vários tratamentos de envelhecimento que podem ser realizados em uma liga β metaestável, um destes é o duplo envelhecimento. O foco deste envelhecimento é obter uma precipitação de fase α mais fina e uniforme. O Objetivo deste trabalho foi estudar o efeito do duplo envelhecimento no módulo de elasticidade da liga Ti-12Mo-13Nb. A liga Ti-12Mo-13Nb foi processada termomecanicamente e passou por um duplo envelhecimento que consistiu primeiramente num envelhecimento na temperatura de 300 ºC por 10 min, 4 e 24 h e um subsequente envelhecimento na temperatura de 500 ºC por 24 h. Como resultado foi observado que não houve variação significativa no módulo de elasticidade com a variação da fração volumétrica da fase ω durante o envelhecimento prévio

Effect of continuum couplings in fusion of halo 11^{11}Be on 208^{208}Pb around the Coulomb barrier

The effect of continuum couplings in the fusion of the halo nucleus $^{11}$Be on $^{208}$Pb around the Coulomb barrier is studied using a three-body model within a coupled discretised continuum channels (CDCC) formalism. We investigate in particular the role of continuum-continuum couplings. These are found to hinder total, complete and incomplete fusion processes. Couplings to the projectile $1p_{1/2}$ bound excited state redistribute the complete and incomplete fusion cross sections, but the total fusion cross section remains nearly constant. Results show that continuum-continuum couplings enhance the irreversibility of breakup and reduce the flux that penetrates the Coulomb barrier. Converged total fusion cross sections agree with the experimental ones for energies around the Coulomb barrier, but underestimate those for energies well above the Coulomb barrier.Comment: 15 pages, 7 figures, accepted in Phys. Rev.