Simple route to prepare stable liquid marbles using poly(ionic liquid)s

Individual “liquid marbles” were prepared by encapsulation of water droplets using flocculated polymer latexes stabilized with poly(ionic liquid)s. At first, the emulsion polymerization of poly(styrene) and poly(methyl methacrylate) using different poly(ionic liquid)s as stabilizers was investigated. Stable latexes composed of spherical polymer particles with sizes ranging between 300 and 700 nm as characterized by dynamic light scattering and scanning electron microscopy were obtained. Subsequently, the polymer particles were flocculated by anion exchange precipitation of the poly(ionic liquid)s provoked by the addition of lithium bis(trifluoromethanesulfonyl)imide salt. After simple filtration and drying processes, the flocculated latexes led to hydrophobic powders with similar micrograin size compared to the original latexes. Very stable “liquid marbles” were prepared by gently shaking water droplets of different volumes onto the hydrophobic powders. The morphology and stability of the liquid marbles were characterized by optical and confocal microscopy.     

Algebraic solution of the mass balanced ADM1 to predict the steady state and to optimise the design of the anaerobic digestion of sewage sludge.

This paper proposes an algebraic solution of the mass and charge balanced ADM1 model to predict the steady state performance of an anaerobic digester for sewage sludge treatment. The algebraic solution consists of three sequential stages: a kinetic stage that considers only the slowest transformations of the model, a stoichiometric stage based on the complete mass fluxes of the biological process and a physicochemical stage from which some digester outputs are calculated. The predictive capacity and the applicability of this model solution are corroborated by its comparison to the differential equation's model solution and the experimental data of a real case study. The algebraic solution is used to explore the digester response under different operational conditions. An example of application is used to verify the potential of the algebraic solution to be used, together with optimisation algorithms, for optimising the design of the digester and the operational conditions for specified performance criteria, such as effluent quality.     

Tunable shapes in supported metal nanoparticles: From nanoflowers to nanocubes

The facile preparation of a range of supported nanoparticles on porous materials was successfully accomplished through the use of a range of environmentally friendly protocols including a modified impregnation/reduction methodology, ultrasounds and microwave irradiation. Materials were characterised by transmission electron microscopy (TEM) and XPS. Different morphologies including conventional nanospheres, nanoflower aggregates, nanorod-like structures and nanocubes were achieved under different conditions. The reported supported nanoparticles are envisaged to have interesting applications in various areas including catalysis, optics and sensors.     

Identification of 2-dodecylcyclobutanone and linear-alkanes as irradiation markers in sliced dry-cured ham

The usefulness of 2-dodecylcyclobutanone (2-DCB) and alkane hydrocarbons as irradiation markers in sliced dry-cured ham was evaluated by solid phase microextraction (SPME)-gas chromatography-mass spectrometry (GC–MS). To that aim, sliced dry-cured ham was irradiated with different irradiation doses and subsequently examined together with non-irradiated dry-cured ham used as a control sample. The SPME conditions utilized were selected as a consequence of performing an optimization process. The results found in this work reflected that the presence of 2-DCB may be used as an irradiation indicator in sliced dry-cured ham since it does not occur in non-irradiated samples. This confirms data reported in the literature on irradiated foods, other than ham. Likewise, the concentrations of alkanes C₁₄–C₁₇ increased considerably in samples irradiated with low doses, although a decrease was observed when high irradiation doses were used. As a consequence, the concentration of these compounds can also be used as an irradiation indicator when doses lower than 1.0 kGy are applied. These results are discussed.     

Preservation of aseptic conditions in absorbent pads by using silver nanotechnology

Silver nanoparticles have been formed in fluff pulp and nanostructured Lyocell fibres by immersion in silver nitrate, and a subsequent transformation of the adsorbed silver ions into elementary silver nanoparticles by physical (thermal/UV) or chemical (sodium borohydride) methods. Microscopy revealed that nanoparticles generated by physical methods were regular in shape and efficiently dispersed, while the chemical reduction produced highly aggregated nanoparticles. Nanoparticle size has been found relevant to guarantee high antimicrobial activity, being the samples with big aggregated silver nanoparticles almost inefficient. Indeed a satisfactory correlation between silver ion release and the antimicrobial efficiency against Escherichia coli and Staphylococcus aureus could be confirmed, and furthermore, the highest concentrations tested were efficient to reduce the microbial load in poultry exudates. This work demonstrates that especially designed absorbent materials could be optimised to preserve aseptic conditions during manipulation, leading to feasible applications of a silver based nanotechnology in food technology.     

A study of zenith radiance in Pamplona under different sky conditions

Zenith radiance was measured in Pamplona (Spain) during sixteen months under different sky conditions. 5th degree polynomials that relate log(L_z) with solar elevation return the best correlations both when considering the entire dataset as well as when data are split into the five sky conditions considered. Besides, we have obtained simple relations, with high correlation coefficients and low Relative Root Mean Square Difference, to predict the values of the mean zenith radiance for a type of sky from the mean zenith radiance values of one or more of the remaining four types. Lastly, we obtained month–hour equal mean zenith radiance contours for each of the five sky types considered in the study as well as for all the skies as a whole.     

A quantitative comparison of methods for classifying burned areas with LISS‐III imagery

Environmental agencies frequently require tools for quick assessments of areas affected by large fires. Remote sensing techniques have been reported as efficient tools to evaluate the effects of fire. However, there exist few quantitative comparisons about the performance of the diverse methods. This study quantitatively evaluated the accuracy of five different techniques, a field survey and four satellite‐based techniques, in order to quickly classify a large forest fire that occurred in 1998 in Solsonès (north‐east Spain) by means of an IRS LISS‐III image. Three pure classes were determined: burned area, unburned vegetation, and bare soil; along with a non‐pure class that we called mixed area. These selected techniques were included into a tree classifier to investigate their partial contribution to the final classification. The most accurate methods when focusing on pure classes were those directly related to the spectral characteristics of the pixel: Reflectance Data and Spectral Unmixing (82% of overall accuracy), versus the poorer performances of Vegetation Indices (70%), Textural measures (72%) and the field survey (68.6%). Since no image processing technique was applied to the Raw Reflectance Data, it can be considered the most cost‐effective method, and the tree classifier reinforces its importance. The results of this study reveal that time consuming and expensive methods are not necessarily the most accurate, especially when potentially easily distinguishable classes are involved.     

New structural insight for antimony(III)-tartrate

Theoretical calculations (density functional theory and ab initio (MP2)) and nuclear magnetic resonance experiments reveal a new metal-oxygen-bridged isomeric form for antimony(III)-l-tartrate that co-exists in solution and in the gas phase with its crystallographically-determined structure.     

Reducing Oxidation of Foods Through Antioxidant Active Packaging Based on Ethyl Vinyl Alcohol and Natural Flavonoids

The development of antioxidant active packaging systems is attracting considerable attention as one of the preferred emerging technologies for reducing the incidence of lipid peroxidation. This work presents the use of ethylene vinyl alcohol copolymer films containing two natural flavonoids, catechin and quercetin, to reduce the oxidation of food. In a series of experiments, these materials showed their ability to reduce the presence of hydroxyl radicals in the package headspace. Packaging fried peanuts in bags manufactured with these active films resulted in a large reduction in the presence of hexanal, a compound produced during peroxidation of the unsaturated fat in peanuts. The results indicated that the materials actively reduced the presence of radical oxidative species although the antioxidants are not released into the food. On exposing sunflower oil to the films, the peroxide values obtained showed that the films actively protected the oil; because of the higher solubility of quercetin in this food product as well as the higher antioxidant capacity, the samples containing this flavonoid were more efficient. Industrial relevance: Active packaging is receiving considerable attention as an emerging technology that can be used to improve the quality and the stability of food, reducing the direct addition of chemicals and the need for changes in formulation. The results of this study show that it is possible to reduce food oxidation without adding antioxidants to the food. The films obtained can be used to protect any type of food, including dry or fatty products. Copyright © 2012 John Wiley & Sons, Ltd.