Mechanical Resuscitation of Chemical Oscillations in Belousov–Zhabotinsky Gels

The conversion of mechanical to chemical energy is a natural phenomenon that few synthetic materials have been able to mimic robustly. The first demonstration of mechanical triggering of Belousov–Zhabotinsky (BZ) oscillations is presented in N‐isopropylacrylamide‐co‐Ru(bpy)₃ gels for which the oscillatory nature of the BZ reaction can be visualized via periodic changes in color. It is demonstrated that BZ oscillations can be induced by the application of compressive stress to gels in which the BZ reaction has attained a steady‐state upon depletion of reagents. Such macroscopic compression physically increases the volume fraction of polymer to which the Ru(bpy)₃ catalyst is grafted and triggers BZ oscillations by utilizing unreacted reagents in the aqueous solution, thus effectively resuscitating and extending the functionality of these oscillatory gels. The applied stress and the initial concentrations of malonic acid are varied to show that there is a critical stress required to trigger and restore these oscillations, and that the period and amplitude of oscillation are tunable. Leveraging this capacity to restore the functionality of the material via applied pressure, sensor applications comprising discrete BZ gels, which are capable of both visually indicating the origin of mechanical loading and transmitting this signal away from the deformation site, are demonstrated. Mechanical resuscitation of such chemical oscillations affords novel approaches to creating pressure sensors based on self‐oscillating gels.     

Non-destructive flavour evaluation of red onion (Allium cepa L.) Ecotypes: An electronic-nose-based approach

This work reports preliminary results on the potential of a metal oxide sensor (MOS)-based electronic nose, as a non-destructive method to discriminate three “Tropea Red Onion” PGI ecotypes (TrT, TrMC and TrA) from each other and the common red onion (RO), which is usually used to counterfeit. The signals from the sensor array were processed using a canonical discriminant function analysis (DFA) pattern recognition technique. The DFA on onion samples showed a clear separation among the four onion groups with an overall correct classification rate (CR) of 97.5%.     

Impact resistance enhancement by adding epoxy ended hyperbranched polyester to DGEBA photocured thermosets

Epoxy-functionalized HBP was synthesized and used as toughening additive in epoxy based UV-curable formulations. The addition of the HBP-epox induced an increase of epoxy group conversion, probably through both an activated monomer mechanism, involving the residual hydroxyl groups, and a copolymerization reaction, involving the epoxy functionalities present on the surface of the HBP. Phase separation was reached during UV-Curing, which assured to maintain the good thermomechanical properties of the cured epoxy matrix improving the impact resistance.     

Full Characterisation of Crambe abyssinica Hochst. Seed Oil

This work was dedicated to reporting the full chemical and physical characterisation of Crambe abyssinica Hochst. seed oil. The oil from the seeds was extracted using n-hexane. The seeds contain about 30?% oil. Density, refractive index, colour, smoke point, viscosity, acidity, saponification value, iodine value, fatty acid methyl esters, the relative position of fatty acids in C₁ and C₃ carbon glycerol, sterols, tocopherols, peroxide value, $ \mathop E\nolimits_{{1{\text{cm}}}}^{1\,\% } $ at 232?nm, and the susceptibility to oxidation measured by the Rancimat method were determined. The oil was found to contain high levels of unsaturated fatty acids, especially C22:1 (63.77?%). The dominant saturated acid was C22:0 (2.14?%). The oil was also found to contain high levels of β-sitosterol (51.93?%), campestanol (21.98?%), and brassicasterol (12.35?%). α-, γ-, and δ-Tocopherols were detected up to levels of 7.67, 125.04, and 3.99?mg/kg, respectively. The induction period (at 110?°C and 20?l/h) of the oil was 8.83?h. The relative position of fatty acids in C₁ and C₃ position was as follows: linoleic 0.45?%, oleic 8.84?%, and erucic 90.72?%. The thermal profile of the oil presented a single peak at ?20.94?°C.     

Detection of adulterated commercial Spanish beeswax

The physical and chemical parameters (melting point and saponification number), and the fraction of hydrocarbons, monoesters, acids and alcohols have been determined in 90 samples of Spanish commercial beeswax from Apis mellifera L. The adulteration with paraffins of different melting point, cow tallow, stearic acid, and carnauba wax were determined by HTGC-FID/MS detection, and the research was focussed mainly on paraffins and microcrystallines waxes. In general, the added adulterant can be identified by the presence of non-naturally beeswax components, and by the differences of values of selected components between pure and adulterated beeswax. The detection limits were determined using pure and adulterated beeswax with different amounts of added waxes (5%, 10%, 20% and 30%). Percentages higher than 1-5% of each adulterant can be detected in the mixtures. Paraffin waxes were confirmed in 33 of the 90 samples analysed at concentrations between 5% and 30%.     

EFFECTS OF MODIFYING REAGENTS ON HUNTITE FLOTATION

Huntite is one of the most important flames retardant additive materials. Although various areas of the world have potential huntite deposits, huntite's place in industry is not well known and a detailed field search for hunite's deposits has not been conducted yet. Formations in the world include different types of minerals such as huntite, hydromagnesite, magnesite, clay minerals, and dolomite. However, physical, chemical, physicochemical, and mineralogical properties of these ores have not been determined yet. In this study, the flotation behavior and electrokinetic properties of huntite were determined in the presence of potassium oleate. The effects of common ions that are expected in flotation pulps, such as Mg²⁺and Ca²⁺, were studied. The influences of pH and modifying reagents such as sodium silicate (Na₂SiO₃·5H₂O) and carboxymethyl cellulose (CMC) on surface properties of huntite were also examined. Electrokinetic measurements showed that the iso-electric point of huntite was approximately 8.0. The surface charge of huntite becomes positive in the presence of 10^?2 M of MgCl₂ and CaCl₂ at all pH values. According to microflotation test results, Mg²⁺ and Ca²⁺ ions have a detrimental effect on the floatability of huntite. Na₂SiO₃ was seen to have no significant effect on the floatability of huntite. Flotation experiments with CMC indicated that it acts as a depressant on huntite.     

An alternating direction algorithm for total variation reconstruction of distributed parameters

Augmented Lagrangian variational formulations and alternating optimization have been adopted to solve distributed parameter estimation problems. The alternating direction method of multipliers (ADMM) is one of such formulations/optimization methods. Very recently, the number of applications of the ADMM, or variants of it, to solve inverse problems in image and signal processing has increased at an exponential rate. The reason for this interest is that ADMM decomposes a difficult optimization problem into a sequence of much simpler problems. In this paper, we use the ADMM to reconstruct piecewise-smooth distributed parameters of elliptical partial differential equations from noisy and linear (blurred) observations of the underlying field. The distributed parameters are estimated by solving an inverse problem with total variation (TV) regularization. The proposed instance of the ADMM solves, in each iteration, an l(2) and a decoupled l(2) - l(1) optimization problems. An operator splitting is used to simplify the treatment of the TV regularizer, avoiding its smooth approximation and yielding a simple yet effective ADMM reconstruction method compared with previously proposed approaches. The competitiveness of the proposed method, with respect to the state-of-the-art, is illustrated in simulated 1-D and 2-D elliptical equation problems, which are representative of many real applications.     

Enhanced sinterability of mechanical alloyed La9.33Si2Ge4O26 oxyapatite powders for IT-SOFC electrolytes

Dense oxyapatite-based La_9.33Si₂Ge₄O₂₆ electrolytes have been successfully prepared by electrical sintering at 1400 °C in static air for 1 h from dry milling La₂O₃, SiO₂ and GeO₂ powders, in adequate atomic proportions, at 350 rpm for 15 h, under controlled environmental conditions, in a planetary ball mill. The densification behaviour of apatite-type phase La_9.33Si₂Ge₄O₂₆ powders synthesized by mechanical alloying was investigated through microstructural evolution with sintering temperature by means of XRD and SEM/EDS analyses. The content of germanium in the sintered samples remained almost constant, suggesting that its incorporation in the apatite phase hinders the high temperature (>1250 °C) volatilization process.     

Hydrogen-rich gas as a product of two-stage co-gasification of lignite/waste plastics mixtures

Under atmospheric pressure, mixtures of lignite with waste plastics were gasified on a laboratory scale. The resulting tar was cracked in a thermal cracking reactor. For experiments, low-ash and low-sulfur lignite was used; the percentage of waste plastics in the mixtures was 10 and 20 wt.%. The main product of co-gasification was hydrogen-rich gas, as by-products, soot and non-gasified solid residue were obtained. It was found that the higher heating value of obtained gas is fully comparable with that of industrial gas from lignite gasification. Probably, at least 20 wt.% of lignite can be replaced with mixed waste plastics in this process. The effect of waste plastics addition on properties of the obtained gas and of the non-gasified solid residue was evaluated and discussed.