Micellar dye shuttle between water and an ionic liquid

The reversible transfer of poly(2-ethyl-2-oxazoline)-block-poly(2-nonyl-2-oxazoline) nanocarriers comprising encapsulated dyes is demonstrated between water and an ionic liquid. This dye transfer concept is shown to be applicable for loading and delivery of dye molecules as well as to provide a protective environment for the encapsulated dye

Exhaust gases reuse in natural gas compression stations for electricity generation

En vista de la preocupación mundial por el aumento del consumo energético, así como, la aplicación de alternativas viables que permitan un mejor aprovechamiento de las fuentes energéticas disponibles, los residuos térmicos surgen como una alternativa energética en aplicaciones industriales en las cuales se generan.  En este sentido, el presente trabajo analiza el potencial energético de los gases de combustión emitidos por una estación de compresión, los cuales pueden utilizarse como fuente de calor para un ciclo Rankine de potencia el cual opera con varios fluidos de trabajo incluyendo nueve de tipo orgánico y el dióxido de carbon (CO2). Las simulaciones demostraron la capacidad de los fluidos de trabajo para incrementar la eficiencia energética de la instalación a partir de los gases de escape de la estacion de compresión, siendo que el tolueno y el CO2 se destacan por presentar los mayores niveles de eficiencia, 21 y 20%, respectivamente. Con el objetivo de generación de potencia del ciclo, se concluye que los fluidos refrigerantes considerados en el análisis no son aptos para el ciclo en los niveles de temperatura evaluados.In view of worldwide concern for the increase in energy consumption, as well as the application of viable alternatives that allow a better use of available energy sources, thermal waste has emerged as an energy alternative in industrial applications in which it is generated. In this sense, the present work analyses the energy potential of combustion gases emitted by a compression station, which can be used as heat source for a Rankine power cycle, which operates with different working fluids, including nine of organic type and the carbon dioxide (CO2). The simulations demonstrated the capacity of the working fluids to increase the energy efficiency of the installation from the exhaust gases of the compression station, where toluene and CO2 stand out for presenting the highest efficiency levels, 21 and 20%, respectively. With the target of generating power, the results showed that refrigerant fluids considered in this analysis are not suitable at the temperature levels evaluated

The reactivity of N-vinylcarbazole in RAFT polymerization: trithiocarbonates deliver optimal control for the synthesis of homopolymers and block copolymers

This is an accepted manuscript of an article published by Royal Society of Chemistry in Polymer Chemistry on 30/04/2012, available online: https://doi.org/10.1039/C3PY00487B The accepted version of the publication may differ from the final published version.The use of various RAFT agents (ZC(S)SR) including dithiobenzoates (Z = Ph), trithiocarbonates (Z = SR′), xanthates (Z = OR′), and conventional and switchable N-aryldithiocarbamates (Z = NR′Ar) in RAFT polymerization of N-vinylcarbazole (NVC) has been explored with a view to establishing which is most effective. Consistent with earlier work, we find that xanthates and N-aryldithiocarbamates give adequate control (dispersities < 1.3) while dithiobenzoates give marked retardation. However, contrary to popular belief, we find that the polymerization of NVC is best controlled with trithiocarbonate RAFT agents, which provide both good molecular weight control, very narrow dispersities (1.1), and high end-group fidelity. The results demonstrate that NVC has intermediate reactivity, i.e. between that of the traditional more activated (MAMs; styrene, acrylates) and less activated monomers (LAMs; vinyl acetate, N-vinylpyrrolidone). A further key to good control is the selection of RAFT agent R substituent to be both a good leaving group and a good initiating radical. The cyanomethyl group meets these criteria whereas phenylethyl is a poor initiating radical for NVC polymerization. A further demonstration of the intermediate reactivity of NVC and the derived propagating radical was the successful preparation of both poly(n-butyl acrylate)-block-poly(N-vinylcarbazole) and poly(N-vinylcarbazole)-block-poly(n- butyl acrylate) with a trithiocarbonate RAFT agent (the sequence of block synthesis is not important). Two-dimensional, liquid chromatography near critical conditions-gel permeation chromatography (LCCC-GPC) has been applied to demonstrate block purity. The corresponding styrene-based blocks can also be successfully synthesized, however, the reinitiation of NVC polymerization by the polystyryl radical proved to be a constraint on the purity of polystyrene-block-poly(N-vinylcarbazole). © 2013 The Royal Society of Chemistry.The authors gratefully acknowledge the Capability Development Fund of CSIRO Materials Science and Engineering for financial support. D.J.K. acknowledges the Office of the Chief Executive of CSIRO for an OCE postdoctoral fellowship and the School of Science and Technology at the University of New England for a start-up grant.Published versio

Effect of scandium triflate on the RAFT copolymerization of methyl acrylate and vinyl acetate controlled by an acid/base “switchable” chain transfer agent

Modulation of the activity of an acid/base switchable dithiocarbamate RAFT agent, cyanomethyl (4-fluorophenyl)(pyridin-4-yl)carbamodithioate, with the Lewis acid scandium triflate (Sc(OTf)3) was investigated to examine the ability to deliver improved control over RAFT copolymerizations involving both more-activated and less-activated monomers—specifically the copolymerization of methyl acrylate (MA) and vinyl acetate (VAc). The introduction of either 0.5 or 1 mol equiv of Sc(OTf)3, with respect to RAFT agent, into a RAFT copolymerization of MA and VAc provides substantially improved control resulting in significantly reduced molar mass dispersities (Đ) (∼1.1–1.3) than achieved in its absence (Đ ∼ 1.3–1.4). Furthermore, similar introduction of Sc(OTf)3 into MA homopolymerization mediated by the same RAFT agent also delivered polymers of very low Đ (∼1.15). Sc(OTf)3 was also found to lower the rate of polymerization and alter the copolymerization reactivity ratios for MA and VAc. Increasing the Lewis acid concentration provides enhanced incorporation of the less active monomer, VAc, into the copolymers ([Sc(OTf)3]/[RAFT] = 0, rMA = 4.04, rVAc = 0.032; [Sc(OTf)3]/[RAFT] = 0.5, rMA = 3.08, rVAc = 0.17; [Sc(OTf)3]/[RAFT] = 1, rMA = 2.68, rVAc = 0.62). Carbon nuclear magnetic resonance (13C NMR) and differential scanning calorimetry (DSC) analysis of preparative samples confirm the enhanced VAc incorporation with increased levels of Sc(OTf)3. Importantly the inclusion of Sc(OTf)3 does not deleteriously affect the thiocarbonylthio end-groups of the RAFT polymers, with high end-group fidelity being observed in all copolymerizations

COCCIÓN DE LADRILLOS MACIZOS EN HORNOS A FUEGO DORMIDO Y CONTINUO Y DETERMINACION DE SUS PROPIEDADES MECÁNICAS

El artículo presenta la cocción de ladrillos macizos en horno natural tipo fuego dormido y en un horno continuo tipo Hoffman ,los cuales fueron fabricados en la ladrillera la Pradera, y la comparación de sus propiedades mecánicas, a las cuales se les realizaron ensayos de tasa de absorción inicial, inmersión durante 24 horas, resistencia a la compresión y módulo de rotura o flexión de acuerdo la norma técnica Colombina NTC- 4017 “Métodos para muestreo y ensayos de unidades de mampostería y otros productos de arcilla”. Para los ensayos de resistencia a la compresión y módulo de rotura se utilizó una máquina Universal tipo Pinzuar PU-100 y el software estadístico Statgraphics. Los resultados se compararon entre la cocción en los dos hornos y con los valores de referencia establecidos en la norma NTC 4205 unidades de mampostería de arcilla cocida, ladrillos y bloques cerámicos

Triazole-Functionalized Mesoporous Materials Based on Poly(styrene- block -lactic acid): A Morphology Study of Thin Films

We report the synthesis of poly(styrene- block -lactic acid) (PS- b -PLA) copolymers with triazole rings as a junction between blocks. These materials were prepared via a ‘click’ strategy which involved the reaction between azide-terminated poly(styrene) (PS-N 3 ) and acetylene-terminated poly(D,L-lactic acid) (PLA-Ac), accomplished by copper-catalyzed azide-alkyne cycloaddition reaction. This synthetic approach has demonstrated to be effective to obtain specific copolymer structures with targeted self-assembly properties. We observed the self-assembly behavior of the PS- b -PLA thin films as induced by solvent vapor annealing (SVA), thermal annealing (TA), and hydrolysis of the as-spun substrates and monitored their morphological changes by means of different microscopic techniques. Self-assembly via SVA and TA proved to be strongly dependent on the pretreatment of the substrates. Microphase segregation of the untreated films yielded a pore size of 125 nm after a 45-min SVA. After selectively removing the PLA microdomains, the as-spun substrates exhibited the formation of pores on the surface, which can be a good alternative to form an ordered pattern of triazole functionalized porous PS at the mesoscale. Finally, as revealed by scanning electron microscopy–energy dispersive X-ray spectroscopy, the obtained triazole-functionalized PS-porous film exhibited some affinity to copper (Cu) in solution. These materials are suitable candidates to further study its metal-caption properties

Photoacoustic effect measurement in aqueous suspensions of gold nanorods caused by low-frequency and low-power near-infrared pulsing laser irradiation

When aqueous suspensions of gold nanorods are irradiated with a pulsing laser (808 nm), pressure waves appear even at low frequencies (pulse repetition rate of 25 kHz). We found that the pressure wave amplitude depends on the dynamics of the phenomenon. For fixed concentration and average laser current intensity, the amplitude of the pressure waves shows a trend of increasing with the pulse slope and the pulse maximum amplitude.We postulate that the detected ultrasonic pressure waves are a sort of shock waves that would be generated at the beginning of each pulse, because the pressure wave amplitude would be the result of the positive interference of all the individual shock waves

In Vitro and In Vivo Feedstuff Digestibility for Snook, Centropomus undecimalis , Juveniles

Abstract Thedegreeofhydrolysis(DH)oftheingredientswasevaluatedforCentropomusundecimalisjuveniles. The in vitro experiment included wheat gluten (WG), corn gluten (CG), soybean meal (SBM) and pretreatedphytase(SBM+phytase),soyproteinconcentrate(SPC),canolameal(CAN)andpretreated phytase (CAN+phytase), poultry byproduct meal (PBPM), chicken meal (CHKM), dried whey (DW), Pota meal (PM: mix of giant squid, fish soluble protein concentrate, crustacean meal, and fish oil), and Protiblend (PTB: aquatic and render mix). The highest acidic DH occurred with PTB (0.38±0.06), CHKM (0.33±0.3), and PBPM (0.25±0.03). In the alkaline condition, PTB (1.6±0.17 and 0.98±0.05 for pyloric caeca and intestine, respectively) and CG (1.04±0.4 and 0.75±0.2 for caeca and intestine, respectively) provided the highest DH values. In vitro digestibility demonstrated that PTB was the highest(85.3%)followedbyPBPM(51.4%),CAN+phytase(47.6%),CG(45.1%),andCHKM(46.5%). The in vivo experiment concerned the WG, CHKM, PBPM, PM, and PTB diets plus a reference diet with fishmeal (Ref diet). The total %DH was different (P0.05). The apparent digestive coefficients ranged from 89.8 to 92.9% for protein and from 68 to 71.4% for energy. KEYWORDS amino acids, in vitro and in vivo digestibility, pH-stat, protein, snoo