Physicochemical and nutritional characteristics of blueberry juice after high pressure processing

This study was carried out to investigate the impact of high pressure processing (HPP) at different pressure (200, 400 and 600 MPa) and treatment times (5, 9 and 15 min) on ascorbic acid, total phenolics, anthocyanin stability and total antioxidant capacity, were also studied at different physicochemical parameters such as pH, °Brix and color. HPP treatments resulted in more than 92% vitamin C retention at all treatment intensities. On the other hand, total phenolic content in the juice was increased, mainly after HPP at 200 MPa for all treatment times. The total and monomeric anthocyanin were similar or higher than the value estimated for the fresh juice being maximum at 400 MPa/15 min (16% increase). Antioxidant capacity values were not statistically different for treatments at 200 MPa for 5–15 min in comparison with fresh juice, however for 400 MPa/15 min and 600 MPa for all times (8–16% reduction), the lowest values were observed for total antioxidant capacity determined with TEAC method. No significant changes were observed in pH and °Brix. Color changes (a*, b*, L* and ΔE) were not visually noticeable for pressurized beverage for all pressures and times.     

Continuous catalyst-free methanolysis and ethanolysis of soybean oil under supercritical alcohol/water mixtures

This work investigates and compares the reaction performance of soybean oil transesterification under supercritical methanol and ethanol, in a continuous catalyst-free process, as a cleaner alternative to conventional chemically catalyzed process. Reactions were performed in a tubular reactor, at 20 MPa, with oil to alcohol ratio of 1:40, varying the temperature in the range from 250 °C to 350 °C, and at two levels of water concentrations, 0 and 10 wt%. Although both processes proceeded with a relatively high reaction rate, conversion achieved by methanolysis was higher than that obtained by ethanolysis. Water positively affected both process: higher ester content and triacylglycerols depletion occurred when 10 wt% water was used compared with anhydrous conditions. Temperature increase favored the conversion of soybean oil to the corresponding methyl or ethyl esters, although temperatures above 300 °C increased the fatty acid degradation degree, a phenomenon responsible for the low ester contents obtained at the highest temperatures and lowest flow rates studied.     

Formulation and characterization of leather and rubber wastes composites

Residues from footwear roughing and carding operations represent 5–15% (w/w) of the solid wastes generated by shoe‐making companies. These wastes are mainly composed by chromium tanned leather and sole materials, and are mostly land filled. Sometimes leaching tests show these wastes as hazardous due to chromium in the leachate. This work aims at a more sustainable option for these wastes by recycling them in styrene butadiene rubber (SBR) and acrylonitrile butadiene rubber (NBR). Thus, they were charged with: (i) ≤1 mm leather waste fibers in the range of 10–25 parts per hundred parts of rubber (phr); and (ii) leather and soles industrial carding and roughing wastes in the range of 20–100 phr. The leather waste fibers‐rubber composites tear strength is increased till 25 phr and both tension and elongation at break decrease within the acceptable range till 12.5 phr for SBR and 15 phr for NBR. In the case of leather and sole carding and roughing wastes, composites tear strength increases till 100 phr, and tension and elongation decrease within the acceptable range till 20 phr. The composite materials at the end of their life cycle may be considered inert or non‐hazardous wastes. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

SEM study of the morphology of asymmetric cellulose acetate membranes produced from recycled agro-industrial residues: sugarcane bagasse and mango seeds

Cellulose, obtained both from sugarcane bagasse and mango seeds, was used for synthesizing cellulose acetate in order to produce asymmetric membranes. These were compared to membranes of commercial cellulose acetate (Rhodia). All produced membranes were asymmetric, characterized by the presence of a dense skin and a porous support. Differences regarding the morphology of the surfaces as well as of the porous support can be noticed. Scanning Electron Microscopy (SEM) showed that the morphology of the superficial layer, responsible for transport, depends on the different lignin content of the starting material and also on the viscosity average molecular weight of the cellulose acetates produced from sugarcane bagasse, mango seed, and Rhodia’s commercial cellulose acetate.     

Synthesis,characterization and evaluation of phosphorylated resins in the removal of Pb<Superscript>2+</Superscript> from aqueous solutions

Phosphinic-derivative poly(styrene-co-divinylbenzene)-based on PS–DVB copolymers with different porosity degrees have been prepared by aromatic electrophilic substitution reaction using PCl₃/AlCl₃ followed by base-promoted hydrolysis. The phosphorylation reaction was analyzed by infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetry (TG/DTG). In addition, the phosphorous content of the phosphorylated copolymers was determined by spectrophotometry using the method based on sodium molybdate reactant so that the extension of that modification could be assessed. The performance of the phosphorylated resins in the extraction of Pb²⁺ from aqueous solutions in a batch system was also evaluated. The Pb²⁺ content was determined by atomic absorption spectrometry (AAS). These materials presented excellent extraction capacity under the contact time of 30 min and pH 6.     

What is coded into memory in the absence of outcome feedback?

Although people often have to learn from environments with scarce and highly selective outcome feedback, the question of how nonfeedback trials are represented in memory and affect later performance has received little attention in models of learning and decision making. In this article, the authors use the generalized context model (Nosofsky, 1986) as a vehicle to test contrasting hypotheses about the coding of nonfeedback trials. Data across 3 experiments with selective decision-contingent and selective outcome-contingent feedback provide support for the hypothesis of constructivist coding (Elwin, Juslin, Olsson, & Enkvist, 2007), according to which the outcomes on nonfeedback trials are coded with the most likely outcome, as inferred by the individual. The relation to sampling-based approaches to judgment, and the adaptive significance of constructivist coding, are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nondestructive evaluation of the depth of surface-breaking cracks in concrete pipes

Surface-breaking cracks affect the material and structural properties of concrete pipes. Therefore, the nondestructive evaluation of the crack depth is important to assess the serviceability of these pipes, which are commonly used in underground infrastructure and trenchless installations (micro-tunneling). This paper presents theoretical, numerical and experimental results for the depth evaluation of surface-breaking cracks. The wall of a concrete pipe is represented as a plate in the numerical and the analytical studies. In the experiments, an ultrasonic piezoelectric transmitter is used as a source. The propagation of the ultrasonic pulse is analyzed using the wavelet transform. A newly proposed wavelet transmission coefficient (WTC) is measured using an equal spacing configuration for the crack depth evaluation in concrete pipes and concrete plates. The results from laboratory and in situ tests show good potential for the practical application of the WTC for the depth evaluation of surface-breaking cracks.     

The rapid synthesis of nanostructured orthorhombic KNbO3 particles by a microwave-assisted hydrothermal method and their characterization

We studied the molar ratio effects of niobium and potassium precursors on the structure and morphology of potassium niobate powders prepared via microwave-assisted hydrothermal synthesis (MaHS). KNbO₃ nanostructures in the form of nanotowers and nanocubes were obtained at reduced synthesis times (30–240 min). The products were characterized via XRD, Raman spectroscopy, SEM, and TEM; band gap calculations used diffuse reflectance data. The results indicate that KNbO₃ nanostructures were obtained with crystallite sizes ranging from 33 to 52 nm. An orthorhombic crystalline structure was formed from the increase of KOH at a molar ratio Nb₂O₅:KOH (1:8 to 1:16 M). The band-gap of 3.1–3.3 eV has potential use in photodegradation applications.