Methane Flow through Organic-Rich Nanopores : The Key Role of Atomic-Scale Roughness

We perform a detailed study of methane flow through nanoporous kerogen. Using molecular dynamics and modeling the kerogen pore with an amorphous carbon nanotube (a-CNT), we show that the reported flow enhancement over Hagen−Poisseuile flow is mainly due to the smoothness, on an atomic scale, of the CNTs. It acts in two ways: first, it helps the mobility of the adsorbed layer; second, and even more important for the flow enhancement, it prevents the dependency on the inverse of the channel length (L) from developing. While the former can incrementally contribute to the flow, the latter effect can explain the orders of magnitude found in comparison to macroscopic results.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Water resources situation at Piracicaba, Capivari and Jundiaí watersheds using a dynamic systems model

Utilizou-se modelo desenvolvido em dinâmica de sistemas, especificamente para as Bacias Hidrográficas dos Rios Piracicaba, Capivari e Jundiaí (BH-PCJ), com cinco simulações para 50 anos de horizonte, como ferramenta para auxiliar na gestão dos recursos hídricos. O modelo estimou as ofertas e demandas de água, e a geração de águas residuárias dos diversos consumidores existentes nas BH-PCJ. Realizou-se simulação utilizando-se das taxas de consumo e de oferta existentes em 2004, e as precipitações com os valores médios constantes. Sob essas premissas, foi encontrado que as demandas de água aumentarão cerca de 76%, que aproximadamente 39% do volume de água disponível terá origem no reúso das águas residuárias, a carga contaminante aumentará em 91%. O Índice de Falkenmark mudará de 1.403 m³ habitante-1 ano-1, em 2004, para 734 m³ hab-1 ano-1 em 2054; e o Índice de Sustentabilidade de 0,44 para 0,20. Foram explorados outros quatro cenários: com fator de mudanças nas precipitações anuais de 90 e 110%; considerando vazão ecológica equivalente a 30% da vazão média diária, e sem nenhuma mudança nas taxas dos outros fatores, somente na vazão ecológica e no consumo domiciliar de água. Todos eles mostraram tendência à futura crise nos recursos hídricos nas BH-PCJ.Using a dynamic systems model specifically developed for Piracicaba, Capivari and Jundiaí River Water Basins (BH-PCJ) as a tool to help to analyze water resources management alternatives for policy makers and decision takers, five simulations for 50 years timeframe were performed. The model estimates water supply and demand, as well as wastewater generation from the consumers at BH-PCJ. A run was performed using mean precipitation value constant, and keeping the actual water supply and demand rates, the business as usual scenario. Under these considerations, it is expected an increment of about ~76% on water demand, that ~39% of available water volume will come from wastewater reuse, and that waste load increases to ~91%. Falkenmark Index will change from 1,403 m³ person-1 year-1 in 2004, to 734 m3 P-1 year-1 by 2054, and the Sustainability Index from 0.44 to 0.20. Another four simulations were performed by affecting the annual precipitation by 90 and 110%; considering an ecological flow equal to 30% of the mean daily flow; and keeping the same rates for all other factors except for ecological flow and household water consumption. All of them showed a tendency to a water crisis in the near future at BH-PCJ.Ministério da Ciência e TecnologiaConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Instituto Nacional de Ciência e Tecnologia em Engenharia da Irrigação (INCT-EI

Using legumes as intercropping to improve soil properties

[SPA] El uso de leguminosas en cultivos asociados hortícolas puede jugar un importante papel tanto en el ciclo de nutrientes como en el ciclo de la materia orgánica y la actividad biológica del suelo. Estos efectos dependen de las especies elegidas para la asociación. Un manejo orgánico de los cultivos también tiende a reducir el impacto negativo que tienen los cultivos intensivos. Así, el objetivo de este estudio fue comparar el efecto de la asociación entre haba (Vicia faba L.) y broccoli (Brassica oleracea L. var. italica) sobre el contenido de humedad, el carbono orgánico del suelo (COS) y nutrientes en un ciclo de cultivo en comparación a los monocultivos de cada especie. En los cultivos asociados además se redujo la fertilización en un 30% con respecto al monocultivo. Los resultados mostraron que la asociación del haba con el brócoli incrementó significativamente el contenido de humedad del suelo, el COS y nutrientes como N, P, K y Mg. Por todo ello, el uso de las leguminosas, en este caso haba, parece una opción viable para mejorar la calidad y fertilidad del suelo, reduciendo el uso de fertilizantes, lo que conlleva a un ahorro en costes y un beneficio ambiental. [ENG] The use of legumes intercropping systems can play an important role both in the nutrient and organic matter cycles and in the biological activity of the soil. The results depend on the species chosen for the association. Organic crop management also tends to reduce the negative impact that intensive crops have. Thus, the objective of this study was to compare the effect of the association between fava bean (Vicia faba L.) and broccoli (Brassica oleracea L. var. italica) on the moisture content, soil organic carbon (SOC) and nutrients in a crop cycle compared to monoculture crops. In associated crops, fertilization was also reduced by 30% compared to monoculture. The results showed that the association of fava bean with broccoli significantly increased the moisture content of the soil, the SOC and nutrients such as N, P, K, and Mg. For all these reasons, the use of legumes, in this case fava beans, seems a viable option to improve the quality and fertility of the soil, reducing the use of fertilizers, which leads to cost savings and an environmental benefit.Este trabajo ha sido financiado por el Ministerio de Ciencia, Innovación y Universidades del Gobierno de España a través del proyecto AsociaHortus [AGL2017-83975-R]. Mariano Marcos agradece al Ministerio de Ciencia, Innovación y Universidades del Gobierno de España el apoyo económico a través del Programa “Ayudas para contratos predoctorales para la formación de doctores 2018” [PRE2018-085702]

Successive magnetic transitions in TbNiAl2 studied by neutron diffraction

We report measurements of DC (AC) magnetic susceptibility and neutron diffraction on TbNiAl2 alloy. The Rietveld refinements of the x-ray and neutron diffraction data are consistent with an orthorhombic structure of the type MgCuAl2 (space group Cmcm). The results of DC (AC)- magnetic susceptibility show two successive magnetic transitions at 20 K and 11.7 K with antiferromagnetic and ferromagnetic (or ferrimagnetic) features, respectively. On the other hand, neutron diffraction patterns show that, below 20 K and down to 12 K, new reflexions appear, confirming the antiferromagnetic character of the transition observed in the macroscopic measurements. Also, at least one of these new reflexions, located at Q 1.2 Å-1, shifts to higher angles when the temperature decreases, indicating an incommensurate magnetic structure. Below 11 K, many reflexions disappear and new reflexions increase, evidencing a new magnetic transition. © Published under licence by IOP Publishing Ltd.This work was supported by MAT 2008-06542-C04 and MAT2011-27573-C04 projects. The authors thank ILL and CRG-D1B for allocating neutron beam tim

Effects of Two Intake Levels of \u3cem\u3eLeucaena leucocephala\u3c/em\u3e on Rumen Function of Sheep

Ruminant production systems based on grass pastures often produce poor animal performance as expressed by growth or reproductive rates. The nutrient imbalance affecting rumen function is due to their low energy and protein intake. The incorporation of leguminous forages such as Leucaena leucocephala, in the diet of ruminants, can stimulate rumen function by providing protein-rich forage (Barros-Rodriguez et al. 2012). This increases the availability of compounds such as ammonia, amino acids and peptides as well as branched short-chain fatty acids, which are produced as a result of degradation of proteins. These substances promote fibre breakdown by acting as ruminal growth activators for rumen bacteria, especially cellulolytic bacteria (Hoover and Stokes 1991). This study aimed to evaluate the effects of 2 intake levels of L. leucocephala on rumen function of sheep fed Pennisetum purpureum

Extraction of pharmaceuticals from hospital wastewater with eutectic solvents and terpenoids: Computational, experimental, and simulation studies

The presence of pharmaceuticals in wastewater, mainly in hospital wastewater, is a serious environmental concern, as they are not removed by conventional processes in wastewater treatment plants and are discharged into the natural environment. This work proposes extracting drugs from hospital wastewater using natural, renewable, and non-toxic solvents such as terpenes and eutectic solvents. First, molecular simulation has been used with the COSMO-RS method performing a massive screening of 43 terpenes, 11 eutectic solvents, and 5 conventional solvents with 31 common pharmaceuticals. The most promising solvents in the screening have been chosen to extract 11 pharmaceuticals simultaneously. Experimental tests with ultrapure water and real hospital wastewater matrices showed a strong influence of pH and matrix on extraction. Under the optimal conditions, global pharmaceutical extraction yields with carvacrol of 94.16 % and the eutectic solvent thymol + dodecanoic acid of 96.86 % were obtained. The regeneration and reuse of both solvents were studied in 5 consecutive stages, showing the carvacrol's high stability and regenerability. Using carvacrol, countercurrent extraction tests showed a fast mass transfer of pharmaceuticals and high extraction yields using low solvent-to-feed (S/F) ratios. The predictions obtained with COSMO-RS were similar to the experimental results, confirming the reliability of this method for selecting alternative solvents for the extraction of pharmaceuticals. Finally, the drug removal process was simulated in a countercurrent extraction. The complete removal of pharmaceuticals from hospital wastewater could be achieved using carvacrol with an S/F of 2.00 at pH 4.00 in an extractor with six equilibrium stagesP2018/EMT-4341, PR65/19-22441, CTM2017-84033-

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Numerical simulation of the thermal fragmentation process in fullerene C60

The processes of defect formation and annealing in fullerene C60 at T=(4000-6000)K are studied by the molecular dynamics technique with a tight-binding potential. The cluster lifetime until fragmentation due to the loss of a C2 dimer has been calculated as a function of temperature. The activation energy and the frequency factor in the Arrhenius equation for the fragmentation rate have been found to be Ea = (9.2 +- 0.4) eV and A = (8 +- 1)10^{19} 1/s. It is shown that fragmentation can occur after the C60 cluster loses its spherical shape. This fact must be taken into account in theoretical calculations of Ea.Comment: 12 pages, 3 figure

Seasons and Other Factors Affecting the Quality of Life of Asthmatic Children

[email protected]: To study the effect of seasons on the health-related quality of life (HRQL) of asthmatic children. Methods: Four groups of asthmatic children 7 to 14 years old were recruited by pediatricians during each season of the year. Their HRQL was assessed by means of the Paediatric Asthma Quality of Life Questionnaire (PAQLQ). Other factors surveyed were asthma severity, atopy, medical treatment, immunotherapy, obesity, parental smoking, and anti-allergic measures. Results: The mean (SD) overall PAQLQ score was highest in summer at 6.2 (1.0) and lowest in autumn at 5.5 (1.2). The same trend was found for domains in summer and autumn, respectively: symptoms, 6.2 (1.0) vs 5.4 (1.4); emotions, 6.5 (0.8) vs 6.0 (1.0); and activities, 5.9 (1.4) vs 5.0 (1.5). Factors such as male gender (odds ratio [OR], 0.60; 95% confi dence interval [CI], 0.41–0.87), being on immunotherapy (OR, 0.59; 95% CI, 0.38–0.92), living in an urban environment (OR, 0.56; 0.33–0.93), and residing on the northern coast of Spain along the Bay of Biscay (OR, 0.56; 0.36-0.89) were independent protective factors against having a total PAQLQ score in the lower tertile. Conversely, being recruited in a primary care setting (OR, 1.55; 1.01–2.38) and having more severe asthma were risks for being in the lower tertile. Conclusions: Irrespective of the severity of the disease, season has a significant influence on the HRQL of asthmatic [email protected]