PHBV nanocomposites based on organomodified montmorillonite and halloysite: The effect of clay type on the morphology and thermal and mechanical properties

The aim of this study was to evaluate the effect of the addition of two types of nanoparticles, organomodified montmorillonite Cloisite® 30B (C-30B), and a tubular like clay, halloysite (HNT), on the morphology and thermal and mechanical properties of poly(hydroxybutyrate-co-hydroxyvalerate) – PHBV nanocomposites. TEM and WAXD results showed a combination of a few tactoids and a partially exfoliated structure for PHBV/C-30B nanocomposites and a good dispersion of HNT in the PHBV matrix. DSC analysis indicated a lower nucleation density with the addition of nanoparticles. Furthermore, the presence of C-30B led to the formation of double melting peaks, related to different crystalline phases. However, a higher melting temperature was obtained for PHBV/HNT nanocomposites. A general increase in the Young’s modulus was observed. However, for PHBV/C-30B nanocomposites, this enhancement was at the expense of the strain at break and impact strength, probably due to the degradation of the polymer during processing.     

Coverage strategy for periodic readings in robotic-assisted monitoring systems

We consider wireless sensor network applications where mobile robots serving as sinks are responsible to collect readings from sensors in a given area and delivering the readings to a central authority within some bounded delay. We refer to these mobile robots as collectors. This scenario raises a number of challenging issues, as we need to define specific coverage strategies to guarantee that: (i) collectors visit any point of the target area on a regular basis, (ii) collectors cover the entire area, and (iii) trajectories take into account the fact that collected data might have spatial correlation. We propose to define trajectories for mobile collectors based on the concept of space-filling curves. We investigate the appropriateness of different space-filling curves to respect a number of requirements (at both the system and applicative levels). By numerically analyzing a number of scenarios, we show that our proposal is both effective in guaranteeing full coverage and in respecting applicative requirements. Our results assess both the delivery delay and the aggregation accuracy of the investigated curves.     

Determination of β-damascenone in alcoholic beverages by reversed-phase liquid chromatography with ultraviolet detection

A new method of analysis was previously developed by this group for the determination of β-damascenone in beer samples. The method consisted of a beer steam distillation, followed by an extraction/concentration step using a C₁₈ SPE column and, finally, analysis by reversed-phase liquid chromatography with detection of β-damascenone at its 227 nm UV-absorption maximum. This work describes further developments of the previous methodology and its application to the identification and quantification of β-damascenone in some other beverages, such as wine, whiskey and brandy. β-Damascenone concentration was monitored during a forced ageing assay of several wines from different regions of Portugal and the influence of heat treatment of wine on β-damascenone concentration was studied. The effect of pH on β-damascenone concentration is also discussed.     

Spinal myoclonus: report of four cases

Four cases of spinal myoclonus are described, three males and one female. The mean age was 51 years (28-75 years). The mean time between the onset of the myelopathy and the myoclonic jerks was 4.3 months (1-8 months). The involuntary movements were determined by trauma, Devic's disease, tuberculous myelopathy and tumor. Three patients had spastic paraplegia with bilateral myoclonus more evident on the right side. The fourth patient had a flaccid paraplegia with symmetrical jerks. The data suggest that different processes (trauma, demyelinating, infection and tumor) affecting the spinal cord may cause the same type of involuntary movements.     

One fate of epimastigote forms of Trypanosoma cruzi injected in mice. An ultrastructural study

Recently, we suggested that epimastigote forms of Trypanosoma cruzi are cleared from circulation of mice by a mechanism independent of lysis and that platelets play an important role in this process. These observations prompted us to look at the fate of epimastigotes in the lung, liver, and spleen of mice injected intravenously with these parasite forms. Using transmission electron microscopy, we observed clumps of epimastigotes and platelets in direct contact with phagocytes in the lumen of capillaries. However, the platelets and parasites were probably separated before phagocytosis because only parasites were found inside the phagocytes. Indeed, most of the phagocytes, although containing epimastigotes in different stages of disintegration, contained no platelets. The removal of parasites from platelets was probably mediated by phagocytes through a mechanism similar to the removal of bacteria from the surface of erythrocytes in humans. These observations suggest that the nonvirulence of T. cruzi epimastigotes in mice is not due to lysis but probably to the inability of these parasite forms to escape destruction by the phagocytes.     

A study of residence time distribution in co‐rotating twin‐screw extruders. Part II: Experimental validation

In the first part of this paper, a new approach to model the residence time distribution (RTD) in a co‐rotating twin‐screw extruder was proposed. It consists of coupling a continuum mechanics approach with a chemical engineering one, yielding an RTD curve without any fitting parameter. However, the choice of ideal reactors that depict the behavior of each particular profile is not evident. In this second part, we present an experimental study based on two types of extruder (Leistritz 30–34 and Clextral BC45), different screw profiles and two measurement techniques (off‐line and in‐line). Global, partial and local RTD curves were obtained, both experimentally and by means of a deconvolution technique. This series of experiments permitted the definition of the best association between ideal reactors and screw elements. Using this association, a comparison has been made between experimental results and theoretical calculations. A good agreement was generally obtained in terms of the RTD shape, delay time, mean residence time and variance.     

A Highly Stable Soybean Oil-Rich Miscella Obtained by Ethanolic Extraction as a Promising Biodiesel Feedstock

Soybean oil is industrially obtained upon hexane extraction. In biodiesel production, soybean oil is submitted to phospholipid removal in order to improve its quality before transesterification. An extraction process was employed to produce ethanolic oil-rich miscella, which can be directly transesterified to produce biodiesel without prior refining. We assessed the oxidative stability of the miscella and three other soybean oils, namely degummed, alkali-refined, and refined–bleached–deodorized (RBD) oil. In vitro antioxidant assays as well as the identification and quantification of tocopherols and isoflavones were also performed. Although hexane-extracted oils showed higher tocopherol contents than miscella, this latter sample and its direct biodiesel demonstrated superior stability in accelerated tests. Miscella also outperformed hexane-extracted oils in all in vitro assays. This behavior can be explained by the presence of phenolic compounds with higher affinity to ethanol than hexane, which was confirmed by the identification of isoflavones glycitein, genistein, and acetyldaidzin, found only in miscella. This study showed that the ethanolic extraction of soybean oil generated a highly stable lipid feedstock for biodiesel manufacture.     

Tire tread compounds with reduced rolling resistance and improved wet grip

The aim of this work is to investigate the replacement of carbon black by silica‐organosilane coupling agent system and the number of processing steps on the mechanical properties, rolling resistance, and wet grip of truck tire treads. Eight compounds were prepared: two formulations based on carbon black, five formulations with the partial replacement of carbon black by a silica‐organosilane coupling agent system, and one formulation with the total replacement of carbon black with silica. The rolling resistance decreased by 10% and the wet grip increased by 18.5% for the compound with 15 phr of silica, 3 phr of organosilane, and three processing steps compared to the standard compound. The processing steps also promoted an improvement in these properties for the composition with 50 phr of carbon black. The partial use of silica reduced the abrasion loss, thus confirming the durability of the compound. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45334.     

‘A Fantasy to Get Employment Around the Area’: Long Commutes and Resident Health in an Outer Urban Master-Planned Estate

The Selandra Rise master-planned estate (MPE) in Melbourne’s south-east growth corridor was designed to create a “healthy and engaged community” through the provision of parks, physical activity opportunities and community facilities. A 5 year longitudinal study researched the impact on residents. Over one third of residents spent 2 to 3 h per day commuting and high levels of dissatisfaction with commutes were found. Longer commute times were associated with poor physical activity and weight outcomes. The paper concludes that provisions for health and wellbeing within an MPE are insufficient when opportunities for local employment are limited and broader locational, connectivity and transport disadvantages are not addressed.