Influence of maize kernel hardness on flour hydration and cooking properties

Knowledge of the association between cooking properties and endosperm hardness may help nutritionist and processors to select raw materials for preparing maize based food products, particularly those eaten as cooked dispersions. Seven commercial maize cultivars differing in hardness were selected to evaluate endosperm hardness on the kernels and some characteristics such as composition and hydration and cooking properties on the grits obtained from those maizes. Results show that the differences in endosperm hardness (directly related to grits protein content) can explain the differences in swelling and amylographic consistencies values. Cultivars with the hardest endosperm show the lowest values at high temperature. They also show the lowest amylographic consistencies. On the other hand softer endosperms present the highest swelling power and the highest amylographic consistencies. These differences are attributed to the restriction for starch swelling caused by the protein matrix. Endosperm hardness measurements and swelling power at 95 degrees C, can be useful to select cultivars that are going to be used to prepare maize based foods like atoles, polenta, etc.     

Line patterning of graphite and the fabrication of cheap, inexpensive, “throw-away” sensors

A new simple method (“line patterning technique”) using only standard office equipment is described whereby clearly defined, electrically conducting patterns of graphite can be deposited on polymer (plastic) or paper substrates. The properties of the conductive patterns have been characterized by electrical conductivity and SEM measurements. Sensors were constructed by using interdigitated patterns of graphite deposited on plastic and paper, and coated with a thin film of conducting electronic polymer, e.g. polyaniline emeraldine salt.     

Simplifying the reaction system for the preparation of polyaniline nanofibers: Re-examination of template-free oxidative chemical polymerization of aniline in conventional low-pH acidic aqueous media

In this study, several polyaniline samples were prepared by oxidative chemical polymerization using only aniline, (NH₄)₂S₂O₈ and HCl in aqueous media at room temperature for morphological studies by SEM (scanning electron microscopy). The results show that polyaniline nanofibers can be obtained by template-free oxidative chemical polymerization in a conventional low-pH acidic aqueous medium (pH ～ 0) at room temperature. The study indicates that it is crucial to employ a mild post-polymerization processing procedure, such as dialysis, to preserve the as-formed morphology of polyaniline nanofibers. Our study also suggests that polyaniline could adopt the nanofiber structure as its intrinsic morphology when it is synthesized in a simple oxidative chemical polymerization system consisting of only aniline, (NH₄)₂S₂O₈ and HCl in an aqueous medium at room temperature.     

Recovery of polyphenols from camu-camu (Myrciaria dubia H.B.K. McVaugh) depulping residue by cloud point extraction

In this study the potential of cloud point extraction formed by a non-ionic surfactant was used in order to separate polyphenols from industrial residues of camu-camu. The effects of operational conditions of the cloud point extraction (CPE) on the polyphenol recovery and volumetric ratio were investigated. The results showed a maximum recovery of 95.71% that was obtained using 7.0 wt% Triton X-114, native pH (3.25), and 80 wt% polyphenol extract at 30 °C. The use of cloud point extraction was successful to recover the polyphenols from agroindustrial residue since it is a simple as well as of low-cost technique.     

Power Equalization Techniques for Three-Phase VSI-Driven Single-Phase Ozone Generators

The purpose of this article is to present a method to equalize power imbalances in single-phase loads driven by three-phase voltage source inverters. The objective is to unbalance the line-to-line voltages in order to equalize the individual load power. The method is evaluated under non-linear loads, considering the dispersion of the high-voltage transformer electrical parameters values usually found in ozone generating systems. Two methods are considered for equalizing the load power. In the progressive method, the power equalization is performed by a microcontroller and works setting up the voltage applied over each load in response to power feedback from the other loads. In addition, Fuzzy Logic concepts are also applied, permitting a fast response, in spite of lower precision in the power balancing. Analytical, simulation and experimental results validate both methods.     

Efficient Strengthening Technique to Increase the Flexural Resistance of Existing RC Slabs

Composite materials are being used with notable effectiveness to increase and upgrade the flexural load carrying capacity of reinforced concrete (RC) members. Near-surface mounted (NSM) is one of the most promising strengthening techniques, based on the use of carbon fiber-reinforced polymer (CFRP) laminates. According to NSM, the laminates are fixed with epoxy based adhesive into slits opened into the concrete cover on the tension face of the elements to strength. Laboratory tests have shown that the NSM technique is an adequate strengthening strategy to increase the flexural resistance of RC slabs. However, in RC slabs of low concrete strength, the increase of the flexural resistance that NSM can provide is limited by the maximum allowable compressive strain in the compressed part of the slab, in order to avoid concrete crushing. This restriction reduces the effectiveness of the strengthening, thus limiting the use of the NSM technique. A new thin layer of concrete bonded to the existing concrete at the compressed region is suitable to overcome this limitation. Volumetric contraction due to shrinkage and thermal effects can induce uncontrolled cracking in the concrete of this thin layer. Adding steel fibers to concrete [steel fiber-reinforced concrete (SFRC)], the postcracking residual stress can be increased in order to prevent the formation of uncontrolled crack patterns. In the present work, the combined strengthening strategy, a SFRC overlay and NSM CFRP laminates, was applied to significantly increase the flexural resistance of existing RC slabs. Experimental results of four-point bending tests, carried out in unstrengthened and strengthened concrete slab strips, are presented and analyzed.     

Simplified sol-gel processing method for amorphous TiO x Memristors

The memristor, a two-terminal memory device with units of resistance, has continued to gain momentum as simpler and more versatile memristive devices are d     

Development of a method to quantify sucrose in soybean grains

The sucrose content of soybean seeds affects the final flavor of soy-derived products. The aim of this work was to develop a simple, low-cost, spectrophotometric method for sucrose quantification in soybean seeds. To achieve this goal, we combined the action of invertase, an enzyme that hydrolyses sucrose into fructose and glucose, with glucose oxidase, an enzyme widely used for glucose quantification. This system was adapted to ELISA plates, making large-scale analyses possible at low cost, with potential application in routine analyses. To validate this method, sucrose content was determined in seeds of 14 soybean cultivars by this new method, as well as by HPLC and the enzymatic method of Stitt. The correlation coefficients were high and significant between the results obtained with the new method and the HPLC method (r = 0.9766) and the Stiff method (0.9461).     

Analyzing cooperative monitoring and dissemination of critical mobile events by VANETs

Wireless Networks - The treatment of mobile and simultaneous critical urban events requires effective actions by the appropriate authorities. Additionally it implies communication challenges in the...     

Experimental annular stratified flames characterisation stabilised by weak swirl

A burner for the investigation of lean stratified premixed flames propagating in intense isotropic turbulence has been developed. Lean pre-mixtures of methane at different equivalence ratios were divided between two concentric co-flows to obtain annular stratification. Turbulence generators were used to control the level of turbulence intensity in the oncoming flow. A third annular weakly swirling airflow provided the flame stabilisation mechanism. A fundamental characteristic was that flame stabilisation did not rely on flow recirculation. The flames were maintained at a position where the local mass flux balanced the burning rate, resulting in a freely propagating turbulent flame front. The absence of physical surfaces in the vicinity of the flame provided free access for laser diagnostics. Stereoscopic Planar Image Velocimetry (SPIV) was applied to obtain the three components of the instantaneous velocity vectors on a vertical plane above the burner at the point of flame stabilisation. The instantaneous temperature fields were determined through Laser Induced Rayleigh (LIRay) scattering. Planar Laser Induced Fluorescence (PLIF) of acetone was used to calculate the average equivalence ratio distributions. Instantaneous turbulent burning velocities were extracted from SPIV results, while flame curvature and flame thermal thickness were calculated using the instantaneous temperature fields. The PDFs of these quantities were analysed to consider the separate influence of equivalence ratio stratification and turbulence. Increased levels of turbulence resulted in the expected higher turbulent burning velocities and flame front wrinkling. Flames characterised by higher fuel gradients showed higher turbulent burning velocities. Increased fuel concentration gradients gave rise to increased flame wrinkling, particularly when associated with positive small radius of curvature.