Development and characterization of a Persian gum–sodium caseinate biocomposite film accompanied by Zingiber officinale extract

Nowadays, instead of synthetic polymers, ecofriendly biopolymers are being widely used as packaging materials; this minimizes packaging waste and environmental pollution. In this study, we aimed to characterize edible films based on sodium caseinate (SC) with the simultaneous use of Zingiber officinale extract (ZOE) and Persian gum (PG). The functional, structural, morphological, and physicochemical aspects of manufactured samples were investigated. Response surface methodology was used to optimize the use of PG (0–1%) and ZOE (0–500 ppm) in the production of the edible films. Fourier transform infrared spectroscopy analysis was carried out to confirm the SC–PG–ZOE interactions. Statistical analysis revealed that the addition of ZOE led to a significant increase in the tensile strength and elongation at break (EB). However, the addition of PG, regardless of ZOE addition, decreased EB. In addition, the incorporation of ZOE into the biopolymer matrix improved the water resistance, water vapor permeability (WVP), and water solubility (WS), whereas the incorporation of PG reduced the transparency. Our findings indicated that minimum of transparency and EB and minimum of WVP and WS were obtained at 0.6% for PG and 360 ppm for ZOE. Therefore, the results of this study suggest a new biocomposite with desirable characteristics and promising potential for producing edible films. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47215.     

An Experimental and Finite Element Study of Cold Spray Copper Impact onto Two Aluminum Substrates

The effect of cold spray temperature and substrate hardness on particle deformation and adhesion has been studied, with particular emphasis on adiabatic shearing leading to melting. Copper particles were cold sprayed onto commercial purity (CP) aluminum and alloy 7050-T7451, with stagnation temperatures 200, 400, and 600 °C. Deposition efficiency, assisted by particle embedding, increased with temperature and was higher on the softer CP substrate. Crater surfaces, adhered particles, and interfaces were characterized by scanning electron microscopy, focused ion beam, and transmission electron microscopy. For comparison, the impact of 15 μm Cu particles was simulated using finite element modeling. A thin layer of material on the substrate-side of the interface was predicted to reach melting point on both substrates at higher impact velocities. Formation of a molten layer was found experimentally. At 600 °C, the effect of substrate heating by the gas jet could not be ignored.     

EXPERIMENTAL INVESTIGATION OF PARAMETERS AFFECTING NANOFLUID EFFECTIVE THERMAL CONDUCTIVITY

The present research reports nanofluid effective thermal conductivity enhancements (ETCE) using an accurate transient short hot wire method system. Preparation of nanofluids was carried out through a two-step method with highly powered pulses similar to that for nanoparticle dispersion in base fluids. Parameters affecting nanofluid heat conductivity such as concentration, sizes, and material of nanoparticle? type of base fluid, temperature, ultrasonic mixing time, and elapsed time after preparation were studied. In the present study, nanoparticles of Al, Al₂O₃, CuO, SnO₂, TiO₂, and SiO₂ with base fluids of water and ethylene glycol were used. Parameters like concentration, size, temperature, and the type of base fluid showed more noticeable effect on the effective thermal conductivity than the others, and mixing time had the least effect. The results showed that any increase in concentration and temperature, and also any decrease in size of nanoparticles and time elapsed after nanofluid preparation, leads to the ETCE of the nanofluid. However, the effects of nanoparticle material, base fluid, and mixing time on thermal conductivity of the nanofluid showed varying trends. Last, a number of mathematical models for prediction of thermal conductivity of nanofluids were applied.     

Application of Conducting Polymer Layer for Measurement of Ag Nanoparticle Concentration Using Surface Plasmon Resonance

An application of polypyrrole and polypyrrole–chitosan were presented to measure the concentration of silver ion and silver nanoparticles using surface plasmon resonance sensor. These results were compared to those for atomic absorption spectroscopy method. The sensing layers were prepared using an electrodeposition on gold layer with the sensor limitation at about 1mg/L, and well correlated to prior atomic absorption spectroscopy results. The sensor with a polypyrrole-chitosan layer was more sensitive and accurate than the sensor with just a polypyrrole layer.     

Experimental Investigation of Al2O3/Water Nanofluid Through Equilateral Triangular Duct With Constant Wall Heat Flux in Laminar Flow

This paper experimentally investigates the heat transfer of an equilateral triangular duct by employing an Al₂O₃/water nanofluid in laminar flow and under constant heat flux conditions to improve the heat transfer performance of this type of duct. The Nusselt numbers were obtained for different nanoparticle concentrations of the nanofluid at various Peclet numbers. The results show that the experimental heat transfer coefficient of Al₂O₃/water nanofluid is higher than that of distillated water. Also, the experimental heat transfer coefficient of Al₂O₃/water nanofluid is higher than the theoretical one. The experimental results also indicate that the heat transfer enhancement increases with increases in the nanofluid volume concentration and Peclet number.     

Separation of ethylene glycol–water mixtures with composite poly(vinyl alcohol)–polypropylene membranes

Composite membranes consisting of a crosslinked poly(vinyl alcohol)(PVA) active layer on top of a porous polypropylene (PP) support were prepared with glutaraldehyde as a crosslinking reagent. The degree of crosslinking and the thickness of the active layer were determined with attenuated total reflection–Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The membranes were used in the pervaporation dehydration of ethylene glycol (EG)–water mixtures. The effects of the crosslinker content and operational conditions, including feed EG concentration and operating temperature, on the permeation flux and selectivity of the PVA–PP composite membranes were investigated. We observed that the dehydration of a 80 wt % EG mixture at temperature of 60°C, a feed flow rate of 1.5 L/min, and a vacuum pressure of 10 mmHg could be effectively performed, and a moderate permeation flux and a high separation factor were obtained, that is, 0.91 kg m⁻² h⁻¹ and 1021, respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A study on melt spinning of polyethylene terephthalate filament yarns containing various concentrations of synthesized CuO nanoparticles

In this research the CuO nanoparticles were synthesized with four different methods then used to produce polyethylene terephthalate (PET) fibers with antibacterial, antifungal, and photocatalytic properties during the melt spinning process. Nanoparticles were synthesized in different ways using copper acetate salt (Cu(CH₃COO)₂) and sodium hydroxide (NaOH). The synthesis of copper oxide (CuO) nanoparticles was confirmed by field-emission scanning electron microscopy (FE-SEM images), EDX patterns, TGA, FTIR, X-ray diffraction pattern XRD, and UV-vis absorption spectrum. The results showed that synthesized nanoparticles exhibited strong antibacterial activity against gram-positive and gram-negative bacteria. Finally, after examining the fibers with different percentages of nanoparticles), fibers containing 1% of nanoparticles were produced using a 20% nanocopper oxide masterbatch as the optimal sample. The presence of nanoparticles in the fiber structure was confirmed by FE-SEM images, EDX, XRD, and FTIR analysis. Furthermore, the tensile properties, thermal behavior, and photocatalytic properties of the fibers were investigated. Evaluation of the antibacterial and antifungal activity of the produced fibers against gram-positive bacteria Staphylococcus aureus and Candida albicans fungus showed about 90% death of bacteria and fungi.     

A Preconcentration Procedure for Determination of Ultra-Trace Mercury (II) in Environmental Samples Employing Continuous-Flow Cold Vapor Atomic Absorption Spectrometry

New functionalized magnetic nanoparticles as solid-phase sorbent were prepared and investigated for extraction of ultra-trace amounts of mercury from environmental samples. The Fe₃O₄ magnetic nanoparticles functionalized with dithizone were characterized by Fourier transform infrared spectrometer. X-ray diffraction and scanning electron microscopy confirmed the size of nanoparticles. Effects of several factors on the extraction procedure were investigated. The optimized conditions were established to be 80 mg of polymer, 8.5 for solution pH, 5 min for adsorption time, 5 min for desorption time, 2 mL for HCl (0.1 mol L^?1)/ thiourea 0.05 % as the eluent, 500 mL for breakthrough volume, and without addition of salt. Under the optimal conditions, the limit of detection, maximum capacity, and preconcentration factor were 0.05 ng mL^?1, 0.557 mmol g^?1, and 250, respectively. Limit of quantification was in the range of 0.2–2 ng mL^?1 for various matrices. Accuracy and precision of the method were about ±2.0 and below 11.1 %, respectively. Finally, the present method has been successfully applied to mercury determination in table salt, green tea, vegetables, toothpaste, and water samples. The mercury content found in the real samples was from 0.6 to 15.74 ng mL^?1 without addition of mercury.     

Impact of fruit processing methods on DNA extraction from transgenic frozen banana products

Isolation of high yield and quality of genomic DNA is paramount for ensuring confidence in molecular analyzing food. This study evaluated five different DNA extraction procedures based on laboratory protocols and commercial kits for their efficiency and also assessed the impact of processing procedures on the DNA degradation in various frozen banana products such as frozen-sliced banana, frozen banana puree, frozen plantain banana, and freeze-dried banana powder. The purity and concentration of DNA obtained from the samples were evaluated by spectrophotometric and gel electrophoresis analysis. Of the various extraction procedures, we applied modified protocols that allow for effective extraction of DNA from banana. This protocol derived from traditional cetyltrimethylammonium bromide method with modifications that allowed removing unwanted polyphenols and polysaccharides. The results confirm that a profound impact on DNA degradation was seen during the processing of banana products, DNA could still be reliably quantified by real-time PCR. Furthermore, frying resulted in further degradations and drying resulted in the most severe changes. It was noted that in different frozen banana products, nopaline synthase fragment is most stable followed by cauliflower mosaic virus 35S and NPTII gene.     

Chromatographic Fingerprinting with Multivariate Data Analysis for Detection and Quantification of Apricot Kernel in Almond Powder

Adulteration of almond powder samples with apricot kernel was solved by gas chromatographic fatty acid fingerprinting combined with multivariate data analysis methods (principal component analysis (PCA), PCA-linear discriminant analysis (PCA-LDA), partial least squares (PLS), and LS support vector machine (LS-SVM). Different almond and apricot kernel samples were mixed at concentrations ranging from 10 to 90% w/w. PCA and PCA-LDA methods were applied for the classification of almonds, apricot kernels, and mixtures. PLS and LS-SVM were used for the quantification of adulteration ratios of almond. Models were developed using a training data set and evaluated using a validation data set. The root mean square error of prediction (RMSEP) and coefficient of determination (R ²) of validation data set obtained for PLS and LS-SVM were 5.01, 0.964 and 2.29, 0.995, respectively. The results showed that the methods can be applied as an effective and feasible method for testing almond adulteration.