Carboxymethyl cellulose plasticized polymer application as bio-material in solid-state hydrogen ionic cell

Energy storage is of great importance in our modern society and further research is required to improve its efficiency and for it to be better for the environment. Thus, plasticized solid biopolymer electrolytes (SBEs) based on carboxymethyl cellulose were prepared for a solid-state hydrogen energy storage application. The transport properties of the SBEs were determined using FTIR deconvolution techniques at the wavenumber region of 1505 to 1355 cm^?1. It was found that the conductivity of SBEs were influenced mainly by ions mobility, μ and diffusion coefficient, D. A solid-state hydrogen ionic cell (SSHC) was then fabricated from the best performing SBE and evaluated. A rechargeable SSHC with the configuration of Zn + ZnSO₄·7H₂O/SBE/MnO₂, produced a maximum open circuit potential of 1.1 V at ambient temperature and showed good rechargeability for 10 cycles. Our findings suggest for a novel practical application of the present bio-electrolyte in the fabrication of solid-state hydrogen ionic cells.     

New simulation approach for tuneable trapezoidal and rectangular piezoelectric bimorph energy harvesters

Enhancing and optimizing the power and operating frequency range of energy harvesters (EH) are important objectives in designing an energy harvester generator. The application of trapezoidal shaped piezoelectric (PZT) cantilever is one way of increasing the harvested power of energy harvesters. Finite element software was used to simulate a tuneable trapezoidal and a rectangular PZT bimorph cantilevers with similar specifications. From the new simulation approach, an open circuit voltage obtained for different resonance frequencies for both generators. The simulation results are compared with the experimental and found to be in good agreement. The results have showed an increase in power over 19 % for the trapezoidal generator over the rectangular generator for a frequency range of 38–122 Hz. The trapezoidal harvester produced maximum power of 0.272 mW at resonance frequency of 34 Hz and acceleration of 2.5 m/s².

     

Effect of temperature on crystallite sizes of copper sulfide nanocrystals prepared from copper(II) dithiocarbamate single source precursor

We report the synthesis of CuS nanoparticles using [Cu(butdtc)₂] as single source precursor thermolysed at two different temperatures. The products were characterized by UV–vis absorption spectroscopy, X-ray diffraction, Transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray analysis and atomic force microscopy. The absorption spectra of the CuS nanocrystals are blue shifted and the XRD were indexed to the hexagonal phase of CuS with nanoparticles obtained at 120 °C showing well defined crystalline structure compared to those obtained at 180 °C. Transmission electron microscopy images showed particles that are almost spherical in shapes with average crystallite sizes of 21–38 nm for CuS1 prepared at 180 °C and 3–7 nm for CuS2 prepared at 120 °C and confirms that the chosen reaction temperature determine the crystallite sizes of the nanoparticles.     

Effects of different surface cleaning procedures on the superficial morphology and the adhesive strength of epoxy coating on aluminium alloy 1050

This study reports the effects of different cleaning procedures on the surface characteristics of the aluminium alloy 1050 substrates and on the adhesive strength of the epoxy coating to this alloy's surface. The cleaning procedures used in this study were (1) degreasing by acetone, (2) alkaline etching by 5 w/w% NaOH solution and (3) alkaline etching by 5 w/w% NaOH solution followed by acid cleaning by 50 v/v% HNO₃ solution. The surface morphology, chemical composition and topography of the cleaned substrates were investigated by field-emission scanning electron microscope (FE-SEM), energy dispersive spectroscopy (EDS) and atomic force microscope (AFM), respectively. The effectiveness of the cleaning procedures was also studied by polarization test and open circuit potential (OCP) measurements. The surface free energy and work of adhesion were obtained on the cleaned samples using contact angle measuring device. Pull-off test was conducted to evaluate the adhesion strength of the epoxy coating on the aluminium substrates. Results revealed that the surface cleaning of aluminium alloy by alkaline etching followed by acid cleaning method was the most efficient procedure for removing the oxide layer from the surface of aluminium compared to other cleaning procedures. The surface roughness, surface free energy, electrochemical activity and adhesion strength of the epoxy coating to the aluminium surface were significantly increased using this surface cleaning procedure.     

Effects of drying on the production of polyphenol-rich cocoa beans

The current study emphasizes on the effects of four drying methods, namely, oven drying, adsorption drying, freeze-drying, and vacuum drying on the total polyphenol content and antioxidant activity of unfermented cocoa beans. The comparison of drying kinetics analysis showed that adsorption drying method dried faster than other methods. On comparing the results of total polyphenol contents and antioxidant activity, freeze-drying method showed the optimal results and the lowest values were recorded by oven drying. The sensory analysis of cocoa beans after drying showed low cocoa flavor and high astringency scores.     

On sampling bias in multiphase flows: Particle image velocimetry in bubbly flows

Measuring the liquid velocity and turbulence parameters in multiphase flows is a challenging task. In general, measurements based on optical methods are hindered by the presence of the gas phase. In the present work, it is shown that this leads to a sampling bias. Here, particle image velocimetry (PIV) is used to measure the liquid velocity and turbulence in a bubble column for different gas volume flow rates. As a result, passing bubbles lead to a significant sampling bias, which is evaluated by the mean liquid velocity and Reynolds stress tensor components. To overcome the sampling bias a window averaging procedure that waits a time depending on the locally distributed velocity information (hold processor) is derived. The procedure is demonstrated for an analytical test function. The PIV results obtained with the hold processor are reasonable for all values. By using the new procedure, reliable liquid velocity measurements in bubbly flows, which are vitally needed for CFD validation and modeling, are possible. In addition, the findings are general and can be applied to other flow situations and measuring techniques.     

A real-time framework for video Dehazing using bounded transmission and controlled Gaussian filter

The haze phenomenon exerts a degrading effect that decreases contrast and causes color shifts in outdoor images and videos. The presence of haze in outdoor images and videos is bothersome, unpleasant, and occasionally, even dangerous. Atmospheric light scattering (ALS) model is widely used to restore hazy images. In this model, two unknown parameters should be estimated: airlight and scene transmission. The quality of dehazed images and video frames considerably depends on those two parameters as well as on the speed and accuracy of the refinement process of the approximated scene transmission, this refinement is necessary to ensure spatial coherency of the output dehazed video. Spatial coherency should be accounted for in order to eliminate flickering artifacts usually noticed when extending single-image dehazing methods to the video scenario. Classic methods typically require high computation capacity in order to dehaze videos in real time. However, when the driver assistance context is considered, these approaches are inappropriate due to the limited resources mobile environments usually have. To address this issue, this study proposes a framework for real-time video dehazing. This framework consists of two stages: single-image dehazing using the bounded transmission (BT) method, which is utilized to dehaze single video frame in real time with high accuracy; and transmission refinement stage using a filter we call controlled Gaussian filter (CGF), which is proposed for the linear and simplified refinement of the scene transmission. To evaluate the proposed framework, three image datasets in addition to two video streams are employed. Experimental results show that the single-image stage in the proposed framework is at least seven times faster than existing methods. In addition, the analysis of variance (ANOVA) test proves that the quality of dehazed images in this stage is statistically similar to or better than those obtained using existing methods. Also, experiments show that the video stage in the proposed framework is capable of real-time video dehazing with better quality than the existing methods.     

A rapid,semi-quantitative test for detection of raw and cooked horse meat residues

Intentional mislabeling and adulteration of meat products with undeclared horse meat is a concern for religious, ethnic, and health reasons and is illegal under regulations mandated and enforced by food regulatory agencies and the Federal Meat Inspection Act. Nonetheless, recent analysis of the meat industry has revealed an apparent increase in the frequency of meat adulteration including intentional horse meat contamination, necessitating a broader use of meat authentication testing. As existing methods for meat speciation are cumbersome and require specialized equipment and/or training, we developed a highly specific lateral flow immunoassay that can rapidly identify raw and cooked horse meat down to 0.01% and 1.0% contamination, respectively in xenogeneic meat sources in about 35 min with no false positive signals observed. Specificity analysis revealed no cross-reactivity with serum albumins or meat derived from chicken, turkey, pig, cow, lamb, and goat. The results of method comparison showed that the assay had similar if not better sensitivity than the commercial ELISA kit and PCR, and required considerably less time to perform than either method. The development of a highly robust and rapid test method capable of detecting trace amounts of horse meat residues should aid food control authorities in their continued efforts to monitor for horse meat adulteration.     

Enhanced photoelectrocatalytic activity of Bi2S3–TiO2 nanotube arrays hetero-structure under visible light irradiation

Constructing heterosystems by sensitizing a wide band gap semiconductor with a narrow band gap semiconductor is an effective way to improve photocatalytic performance. Bismuth sulfide (Bi₂S₃) has a direct band gap of 1.38 eV and shows great potential in capturing visible light, which makes it a good candidate for photocatatlytic applications. In this work, Bi₂S₃ nanoparticles were efficiently deposited on TiO₂ nanotube arrays (Bi₂S₃-TNTAs) by sequential chemical bath deposition (CBD) method to enhance visible light response of the photocatalytic system. Notably, a high-throughput screening method of scanning photoelectrochemical microscopy (SPECM) was exploited to evaluate photoelectrochemical response of the as-prepared composites and to find out the optimized photocatatlytic system. The effects of Bi₂S₃ nanoparticles on visible light absorption and photoelectrocatalytic hydrogen production rate of the TiO₂-system were investigated in detail. When adopted as photoanode, the optimized heteroelectrode exhibited a more than 13-fold enhancement in hydrogen production rate. The result of electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) shows that photo-generated charges excited under visible light in Bi₂S₃-TNTAs composites are efficiently separated, which gives rise to the superior photoelectrocatalytic performance of the Bi₂S₃-TNTAs photoanodes.