Effect of Water Absorption and Stacking Sequences on the Tensile Properties and Damage Mechanisms of Hybrid Polyester/Glass/Jute Composites.

The aim of this work is to analyze the effect of water absorption on the mechanical properties and damage mechanisms of polyester/glass fiber/jute fiber hybrid composites obtained using the compression molding and vacuum-assisted resin transfer molding (VARTM) techniques with different stacking sequences. For this purpose, the mechanical behavior under tensile stress of the samples was evaluated before and after hygrothermal aging at different temperatures: TA, 50 °C, and 70 °C for a period of 696 h. The damage mechanism after the mechanical tests was evaluated using SEM analysis. The results showed a tendency for the mechanical properties of the composites to decrease with exposure to an aqueous ambient, regardless of the molding technique used to conform the composites. It was also observed that the stacking sequence had no significant influence on the dry composites. However, exposure to the aqueous ambient led to a reduction in mechanical properties, both for the molding technique and the stacking sequence. Damage such as delamination, fiber pull-out, fiber/matrix detachment, voids, and matrix removal were observed in the composites in the SEM analyses.

Assessing thermal adaptation of a global sample of Aspergillus fumigatus: Implications for climate change effects.

Aspergillus fumigatus is a common environmental mold and a major cause of opportunistic infections in humans. It's distributed among many ecological niches across the globe. A major virulence factor of A. fumigatus is its ability to grow at high temperature. However, at present, little is known about variations among strains in their growth at different temperatures and how their geographic origins may impact such variations. In this study, we analyzed 89 strains from 12 countries (Cameroon, Canada, China, Costa Rica, France, India, Iceland, Ireland, New Zealand, Peru, Saudi Arabia, and USA) representing diverse geographic locations and temperature environments. Each strain was grown at four temperatures and genotyped at nine microsatellite loci. Our analyses revealed a range of growth profiles, with significant variations among strains within individual geographic populations in their growths across the temperatures. No statistically significant association was observed between strain genotypes and their thermal growth profiles. Similarly geographic separation contributed little to differences in thermal adaptations among strains and populations. The combined analyses among genotypes and growth rates at different temperatures in the global sample suggest that most natural populations of A. fumigatus are capable of rapid adaptation to temperature changes. We discuss the implications of our results to the evolution and epidemiology of A. fumigatus under increasing climate change.

Study of enantioseparation of ß-blockers using amylose tris(3-chloro-5-methylphenylcarbamate) as chiral stationary phase under polar-organic, reversed-phase and hydrophilic interaction liquid chromatography conditions.

In this study, we describe the experimental variables influencing enantioseparation of twelve ß-blockers when analyzed under polar-organic, reversed-phase and hydrophilic interaction liquid chromatography conditions on a column with immobilized amylose tris(3-chloro-5-methylphenylcarbamate) as chiral stationary phase. Regarding polar-organic mode, two component mobile phases consisting of methanol, ethanol or acetonitrile with the addition of basic additives such as diethylamine, triethylamine, mono-ethanolamine, ethylendiamine or trifluoroacetic acid/diethylamine mixture were evaluated. Studies of retention at different temperatures were also performed. In reversed-phase mode, mixtures consisting of methanol or acetonitrile with either aqueous boric acid-borate buffer or sodium hydrogen carbonate-carbonate buffer solutions were compared aiming to study the influence of organic modifier as well as buffer type and pH on resolution. In addition, a systematic evaluation of the retention factors of ß-blockers enantiomers in hydro-organic eluents containing acetonitrile in presence of diethylamine as additive was carried out by increasing progressively the water content, in order to check for retention dependencies indicative of the interplay of both hydrophilic interaction liquid chromatography and reversed-phase modes.

Chiral separation of several pesticides on an immobilized amylose tris(3-chloro-5-methylphenylcarbamate) column under polar-organic conditions. Influence of mobile phase and temperature on enantioselectivity.

In this work, the use of different solvents and temperatures was explored, aiming to evaluate their influence on the enantioseparation of pesticides by HPLC in polar-organic conditions, employing a column containing immobilized amylose tris(3-chloro-5-methylphenyl-carbamate). The chiral separation of seventeen different pesticides widely used as herbicides, fungicides, insecticides and precursors were studied. The mobile phases included methanol, ethanol, iso-propanol, n-propanol and acetonitrile; either pure or containing additives such as diethylamine, trifluoroacetic acid, formic acid, acetic acid or mixtures thereof. We studied the influence of these eluents on chiral separation of those pesticides in terms of retention factor, enantioselectivity, enantioresolution and peak symmetry. Regarding temperature influence, evaluated within the range 5 - 40 °C, nearly all the compounds decreased their retention and selectivity factors with the increase in temperature, although the effect was dependent on the mobile phase solvent. Moreover, estimation of thermodynamic parameters was performed based on linear van´t Hoff plots.

Periodicity of the growth-band formation in vertebrae of juvenile scalloped hammerhead shark Sphyrna lewini from the Mexican Pacific Ocean.

The age of 296 juvenile scalloped hammerhead sharks Sphyrna lewini caught by several fisheries in the Mexican Pacific Ocean from March 2007 to September 2017 were estimated from growth band counts in thin-sectioned vertebrae. Marginal-increment analysis (MIA) and centrum-edge analysis (CEA) were used to verify the periodicity of formation of the growth bands, whereas elemental profiles obtained from LA-ICP-MS transect scans in vertebrae of 15 juveniles were used as an alternative approach to verify the age of the species for the first time. Age estimates ranged from 0 to 10+ years (42-158.7 cm total length; LT ). The index of average percentage error (IAPE 3.6%), CV (5.2%), bias plots and Bowker's tests of symmetry showed precise and low-biased age estimation. Both MIA and CEA indicated that in the vertebrae of juveniles of S. lewini a single translucent growth band was formed during winter (November-March) and an opaque band during summer (July-September), a period of faster growth, apparently correlated with a higher sea surface temperature. Peaks in vertebral P and Mn content spatially corresponded with the annual banding pattern in most of the samples, displaying 1.19 and 0.88 peaks per opaque band, respectively, which closely matched the annual deposition rate observed in this study. Although the periodicity of growth band formation needs to be verified for all sizes and ages representing the population of the species in the region, this demonstration of the annual formation of the growth bands in the vertebrae of juveniles should lead to a re-estimation of the growth parameters and productivity of the population to ensure that it is harvested at sustainable levels.

Thermodynamic DFT analysis of natural gas.

Density functional theory was performed for thermodynamic predictions on natural gas, whose B3LYP/6-311++G(d,p), B3LYP/6-31+G(d), CBS-QB3, G3, and G4 methods were applied. Additionally, we carried out thermodynamic predictions using G3/G4 averaged. The calculations were performed for each major component of seven kinds of natural gas and to their respective air + natural gas mixtures at a thermal equilibrium between room temperature and the initial temperature of a combustion chamber during the injection stage. The following thermodynamic properties were obtained: internal energy, enthalpy, Gibbs free energy and entropy, which enabled us to investigate the thermal resistance of fuels. Also, we estimated an important parameter, namely, the specific heat ratio of each natural gas; this allowed us to compare the results with the empirical functions of these parameters, where the B3LYP/6-311++G(d,p) and G3/G4 methods showed better agreements. In addition, relevant information on the thermal and mechanic resistance of natural gases were investigated, as well as the standard thermodynamic properties for the combustion of natural gas. Thus, we show that density functional theory can be useful for predicting the thermodynamic properties of natural gas, enabling the production of more efficient compositions for the investigated fuels. Graphical abstract Investigation of the thermodynamic properties of natural gas through the canonical ensemble model and the density functional theory.

Licuefacción caaalítica directa de carbones. efecto de la temperatura / Direct catlytic liquefaction of coals. effect of the temperatree / Liquefaçã catalíítica directa de carvão. efeito da temperatura

Un carbón bituminoso alto volátil del departamento de Cundinamarca (Colombia), se licuó en presencia de un catalizador polimetálico en un reactor discontinuo de 500 mL a 370, 410 y 450 °C, en atmósfera de hidrógeno, usando tetralina como solvente dador de hidrógeno y tiempo de residencia de 1 h. El uso del catalizador incrementó la conversión del carbón y el rendimiento hacia la fracción de aceites a medida que aumentó la temperatura. El máximo rendimiento a aceites obtenido fue del 67% a 450 °C.

A high volatile bituminous coal from the Department of Cundinamarca (Colombia), was liquefied in the presence of a polymetallic catalyst in a 500 mL batch reactor at 370, 410 and 450 °C under hydrogen atmosphere, using tetralin as hydrogen donor solvent and residence time of 1 h. When the catalyst was used and the temperature increased, the coal conversion and the oil yield increased too. The maximum oil yield obtained was 67% at 450 °C.

Um carvão betuminoso alto volátil do Departamento de Cundinamarca foi liquefeito na presença de um catalisador polimetálico num reactor de 500 mL a 370,410 e 450 °C em atmosfera de hidrogênio, usando tetralina como doador de hidrogênio do solvente e tempo de residencia de 1 h. O uso do catalisador aumentou a conversão do carvão e rendimento de óleo com o aumento da temperatura. O rendimento máximo de óleo obtido foi de 67% a 450 °C.

Efeito de temperaturas de armazenamento e de genótipos de feijoeiro sobre a resistência a Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae) / Effect of storage temperature and bean genotypes on the resistance to Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae)

Aiming to evaluate the effect of different temperatures of storage and bean genotypes, Phaseolus vulgaris L., on the expression of resistance to the bean weevil, Acanthoscelides obtectus (Say), tests were carried out with the genotypes Arc.1S, Arc.1, Arc.2, Arc.4 and Carioca Pitoco. Grains of Arc.1S and Arc.2 expressed resistance to A. obtectus at 20ºC, 25ºC and 30ºC; the resistance of Arc.1 was reduced as the storage temperature increased from 25ºC to 30ºC. The interaction genotypes x temperatures was significant, indicating that the increase of temperature affects the expression ofresistance. The 20ºC temperature was the most suitable to allow bean genotypes to be discriminate in terms of resistance.

Visando avaliar os efeitos de diferentes temperaturas de armazenamento e de genótipos de feijoeiro, Phaseolus vulgaris L., sobre a expressão da resistência ao caruncho, Acanthoscelides obtectus (Say), realizaram-se ensaios com os genótipos Arc.1S, Arc.1, Arc.2, Arc.4 e Carioca Pitoco. Os grãos de Arc.1S e Arc.2 expressaram resistência a A. obtectus nas temperaturas de 20ºC, 25ºC e 30°C; a resistência do genótipo Arc.1 diminuiu à medida que a temperatura de armazenamento foi elevada de 25ºC para 30ºC. A interação genótipos x temperaturas foi significativa, indicando que a elevação da temperatura afeta a expressão da resistência. A temperatura de 20ºC foi a mais adequada para discriminar os genótipos de feijoeiro, quanto a resistência.