Influence of discrete fibre reinforcement on the uniaxial compression response and seismic wave velocity of a cement-stabilised sandy-clay

A sandy clay from the northeast region of Portugal has been reinforced with polypropylene fibres and cement, and seismic wave velocity measurements and uniaxial compression strength tests were performed. Results showed that the fibre induce variations on the wave's velocity that cannot be related to real changes in the material stiffness. Therefore, care should be used when using this technique in fibre reinforced soils. The addition of fibres resulted in an increase of compression strength of the mixtures, for every cement content. Regarding the stiffness, the fibres proved to be increasingly effective with na increase in cementation, especially at the early stages of the stressestrain curve, when the secant deformability modulus increases with fibre content. However, no influence of the discrete reinforcement was detected on the peak and post-peak stages of the loading process. Fibre length showed also to be influential on strength and stiffness

Towards a greener endoscopy: considerations on the strategies to improve sustainability

Climate crisis is dramatically changing life on earth. Environmental sustainability and waste management are rapidly gaining centrality in quality improvement strategies of healthcare, especially in procedure- dominant fields such as gastroenterology and digestive endoscopy. Therefore, healthcare interventions and endoscopic procedures must be evaluated through the ‘triple bottom line’ of financial, social, and environmental impact. The purpose of the paper is to provide information on the carbon footprint of gas- troenterology and digestive endoscopy and outline a set of measures that the sector can take to reduce the emission of greenhouse gases while improving patient outcomes. Scientific societies, hospital execu- tives, single endoscopic units can structure health policies and investment to build a “green endoscopy”. The AIGO study group reinforces the role of gastrointestinal endoscopy professionals as advocates of sus- tainability in digestive endoscopy. The “green endoscopy” can shape a more sustainable health service and lead to an equitable, climate-smart, and healthier future.info:eu-repo/semantics/publishedVersio

Influence of fibre reinforcement on the post-cracking behaviour of a cement-stabilised sandy-clay subjected to indirect tensile stress

An experimental campaign was carried out to determine the influence of polypropylene fibre content and length on the post-cracking response of a sandy-clay stabilised with different cement contents. Three main sets of specimens were prepared: cement-stabilised specimens with two cement contents (5% and 10%); fibre-reinforced specimens with three fibre contents (0.1%, 0.2% and 0.3%) and cement-fibre-reinforced specimens combining the mentioned fibre and cement contents. Tensile tests on the fibres and indirect tensile tests and triaxial compression tests on the prepared specimens were conducted. Results show that the post-cracking behaviour is strongly affected by the combination of fibre and cement content as well as fibre length. Pull-out was the governing failure mode. Post-peak tension loss rate increased with fibre content, as a result of the loss of influence of the fibres on the post-peak behaviour. On the contrary, an increase in fibre content resulted in higher pre-peak strength gain rates and higher peak stresses.info:eu-repo/semantics/publishedVersio

Photoluminescence and electrical study of fluctuating potentials in Cu2ZnSnS4-based thin films

In this work, we investigated structural, morphological, electrical, and optical properties from a set of Cu2ZnSnS4 thin films grown by sulfurization of metallic precursors deposited on soda lime glass substrates coated with or without molybdenum. X-ray diffraction and Raman spectroscopy measurements revealed the formation of single-phase Cu2ZnSnS4 thin films. A good crystallinity and grain compactness of the film was found by scanning electron microscopy. The grown films are poor in copper and rich in zinc, which is a composition close to that of the Cu2ZnSnS4 solar cells with best reported efficiency. Electrical conductivity and Hall effect measurements showed a high doping level and a strong compensation. The temperature dependence of the free hole concentration showed that the films are nondegenerate. Photoluminescence spectroscopy showed an asymmetric broadband emission. The experimental behavior with increasing excitation power or temperature cannot be explained by donor-acceptor pair transitions. A model of radiative recombination of an electron with a hole bound to an acceptor level, broadened by potential fluctuations of the valence-band edge, was proposed. An ionization energy for the acceptor level in the range 29–40 meV was estimated, and a value of 172 ±2 meV was obtained for the potential fluctuation in the valence-band edge

Catalytic bi-reforming of methane for carbon dioxide ennoblement

New processes that may reduce the net carbon emissions and contribute to a more circular economy are needed. Bi-reforming of methane (BRM) is a promising method for syngas production, with a hydrogen-to-carbon monoxide ratio of two in the reaction products, relevant for example when the purpose is methanol synthesis. In this work, reaction studies were carried out over a nickel-based catalyst varying the temperature (798-1123 K). Three main temperature zones have been identified; a low temperature zone where the conversion of carbon dioxide is almost null, a middle temperature range where steam reforming of methane (SRM) is dominant while the conversion of carbon dioxide via dry reforming of methane (DRM) is low, and finally a high temperature range where DRM becomes more significant. The results show that syngas can be successfully produced using this process. For the range of operating conditions studied, the carbon dioxide and methane conversions increase with temperature, reaching 40% and 100%, respectively at the largest temperature studied. However, the production of syngas in a molar ratio of 1:2 for CO-to-H-2 requires the use of high temperatures. Most probably the nickel agglomerates on top of the gamma-alumina support are responsible for the poor catalyst performance. (C) 2019 Published by Elsevier Ltd

Optimization of injection blow molding: part I – defining part thickness profile

Manuscript DraftThis paper suggests a methodology based on a neuroevolutionary approach to optimize the use of material in blow molding applications. This approach aims at determining the optimal thickness distribution for a certain blow molded product as a function of its geometry. Multiobjective search is performed by neuroevolution to reflect the conflicting nature of the design problem and to capture some possible trade-offs. During the search, each design alternative is evaluated through a finite element analysis. The coordinates of mesh elements are the inputs to an artificial neural network that is evolved and whose output determines the thickness for the corresponding location. The proposed approach is applied to the design of an industrial bottle. The results reveal validity and usefulness of the proposed technique, which were able to distribute the material along mostcritical regions to adequate mechanical properties. The approach is general and can be applied to products with different geometries.Programa Operacional para a Competitividade e Internacionalização -COMPETE 2020, projectos POCI-01-0145-FEDER-007688 e POCI-01-0247-FEDER-00279

Construction of a biocompatible and antioxidant multilayer coating by layer-by-layer assembly of -carrageenan and quercetin nanoparticles

The present work aimed at the construction and characterization of a multilayer coating based on -carrageenan and quercetin-loaded lecithin/chitosan nanoparticles (Np) by the layer-by-layer technique and the evaluation of its antioxidant capacity and potential cytotoxicity in vitro. The multilayered coating was successfully self-assembled, as confirmed by UV-Vis spectroscopy, contact angle, atomic force microscopy (AFM), and scanning electron microscopy (SEM). Multilayered coatings showed to have antioxidant capacity, with a DPPH radical scavenging activity of 31.32±3.13% and a result of the FRAP assay of 799.41±95.39 M of ferrous ion (Fe2+) equivalent. These coatings were also shown to be devoid of cell toxicity, as evaluated by determination of nitric oxide production and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test. The alveolar macrophages culture was tested in the presence of the -carrageenan/quercetin-Np multilayer coating and showed a cell viability of 91.3±9.6%. These results suggest that this multilayered coating is adequate for surfaces modification in view of biomedical and food industry applications.This work was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The authors would also like to thank the Brazilian Government for support given by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). Carneiro-daCunha, M.G. expresses her gratitude to the CNPq for research grant.info:eu-repo/semantics/publishedVersio

Quercetin-loaded lecithin/chitosan nanoparticles: physicochemical characterization

Quercetin is an abundant flavonoid in food plants and has been extensively investigated for its pharmacological effects that include anti-tumor, anti-inflammatory, antioxidant, and hepatoprotective activities. Being sparingly soluble in water and subject to degradation in aqueous intestinal fluids, the absorption of quercetin is limited upon oral administration. The aim of this study was to encapsulate quercetin on lecithin/chitosan nanoparticles by auto-assembled technique for improvement its solubility, stability and oral bioavailability. The nanoparticles were obtained injecting a solution of lecithin (2.0 mg.mL-1) and quercetin (70 µg.mL-1) in ethanol (99%) into a chitosan (0.1 mg.mL-1) aqueous solution (pH 3.0), under mechanic stirring. The nanoparticles were characterized by measuring particle size, zeta potential and encapsulation efficiency. The morphology of nanoparticles was evaluated by transmission electron microscopy. Antioxidant activity of nanoparticles and free quercetin was also evaluated using the scavenging of 1,1-diphenyl-2-picrylhydrazyl radical and anti-lipid peroxidation. The nanoparticles showed mean diameter of 168.58±20.94 nm, with polydispersity index of 0.26±0.02, zeta potential of +56.46±1.94 mV, and encapsulation efficiency of 96.13±0.44%. The nanoparticles showed spherical shape and an antioxidant activity more effective than free quercetin. This work demonstrated that the quercetin was successfully encapsulated suggesting that the lecithin/chitosan nanoparticles is a promising delivery system to enhance the oral absorption and water solubility of quercetin.info:eu-repo/semantics/publishedVersio

Structural and mechanical properties of organogels: Role of oil and gelator molecular structure

Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.foodres.2017.03.021.This work aims at evaluating the influence of oil and gelator structure on organogels' properties through rheological measurements, polarized microscopy and small-angle X-ray scattering (SAXS). Four different food-grade gelators (glyceryl tristearate GT; sorbitan tristearate ST; sorbitan monostearate SM and glyceryl monostearate - GM) were tested in medium-chain triglyceride and high oleic sunflower (MCT and LCT, respectively) oil phases. Organogels were prepared by mixing the oil phase and gelator at different concentrations (5, 10, 15, 20 and 25%) at 80 °C during 30 min. All organogels presented birefringence confirming the formation of a crystalline structure that changed with the increase of the gelator concentration. Through the evaluation of SAXS peaks it has been confirmed that all structures were organized as lamellas but with different d-spacing values. These particularities at micro- and nanoscale level lead to differences in rheological properties of organogels. Results showed that the oil type (i.e. medium- and long-chain triglyceride) and hydrophilic head of gelators (i.e. sorbitan versus glyceryl) exert influence on the organogels physical properties, but the presence of monostearate leads to the formation of stronger organogels. Moreover, gels produced with LCT were stronger and gelled at lower organogelator concentration than MCT.The authors thank the FCT Strategic Project of UID/BIO/04469/2013 unit, the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the project “BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes”, REF. NORTE-07- 0124-FEDER-000028 co-funded by the Programa Operacional Regional do Norte (ON.2 – O Novo Norte), QREN, FEDER. The financial support of CAPES/FCT Project “Nanotechnological systems based in biocompatible ingredients: characterization, controlled release and in vitro digestion” (CAPES/FCT n° 348/13) and CNPq (Universal 479459/2012-6) are gratefully acknowledged. The authors also thank the Brazilian Synchrotron Light Laboratory (LNLS) for the opportunity to carry out SAXS measurements.info:eu-repo/semantics/publishedVersio

Parâmetros seminais de machos ovinos de diferentes grupos genéticos.

Objetivou-se verificar as diferenças de parâmetros seminais de animais das raças Dorper (D), Texel (T), Ile de France (I), Santa Inês (S) e seus cruzamentos (½ D+½S, ½I+½S e ½T+½S), criados na região Sudeste do Brasil. Foram avaliadas as características: perímetro escrotal à puberdade, volume do ejaculado, motilidade individual progressiva, vigor, concentração do sêmen, defeitos maiores, defeitos menores e defeitos totais. Foram feitas as análises de variância para comparação entre os grupos genéticos e testados os efeitos de peso, idade à puberdade e perímetro escrotal, como covariáveis no modelo. As médias de idade e peso à puberdade foram 196,89 ± 46,54 dias e 38,53 ± 6,35 kg, respectivamente. O efeito de grupo genético foi significativo apenas para a variável concentração. De modo geral, conclui-se, o uso da raça Santa Inês como componente nativo do programa de cruzamentos não afetou os atributos determinantes da puberdade nos animais cruzados resultantes