Cross-linked electrospun polyvinyl alcohol/sodium caseinate nanofibers for antibacterial applications

In this study, the polyvinyl alcohol (PVA) and sodium caseinate (SC) nanofibers were produced by a single-fluid electrospinning method from their blends. Afterward, the cross-linking process with two different methods was applied to the PVA/SC (70/30, v/v) ratio, which was selected according to the surface and mechanical properties of the electrospun mat. In the first method, different ratios (15%, 20%, 25%, and 30%) of glutaraldehyde (GLA) cross-linking agents were added to the PVA/SC solution and then, PVA/SC/GLA nanofibers were obtained. In the second method (in-situ method), the nanofibers obtained from the PVA/SC solution were cross-linked by dipping into the cross-linking solution. After, PVA/SC/GLA/Zinc oxide nanoparticles (ZnO NP) mats were obtained by adding ZnO NP at different rates to the PVA/SC/GLA (7030-25GLA) solution, which was chosen according to the results of thermal, mechanical, and moisture test. In addition, performing tests, a cytotoxicity test for fibroblast cell line (L929), and in vitro antibacterial test for Escherichia coli and Staphylococcus aureus were also applied to them. Therefore, the usability of PVA/SC/GLA/ZnO NP nanofibers as an antibacterial effective wound dressing was investigated. Due to the high toxic effect of GLA, it was found that PVA/SC/ZnO cross-linked nanofibers are not suitable for wound dressing use. However, it was determined that the PVA/SC nanofiber cross-linked by the in-situ method had high cell viability according to the cytotoxicity test result and thus could be used as a fibroblast tissue scaffold.     

Sol-gel synthesis of Ru(II) complex of 3-4,5-dihydroimidazol-1-yl-propyltriethoxysilane aerogels and xerogels

The preparation and the measurement of some properties of Ruthenium (II) coordinated 3-4,5-dihyroimidazol-1-yl-propyltriethoxysilane have been achieved. The organosilicon precursor chosen for this study was N-aminoethyl-3-aminopropyltriethoxysilane converted to 3-4,5-dihydroimidazol-1-yl-propyltriethoxysilane that was then coordinated with ruthenium (II). FT-IR spectroscopy, DTA and TGA analysis were used to characterize the bond formation during gelation, aging and drying of gels. The prepared aerogels are low-density 0.19–0.30 g/cm³ amorphous materials with surface areas of 405 to 530 m²/g. The resulting aerogel catalysts exhibited unique structural and chemical properties. Received: 29 August 1999/Revised version: 6 November 1999/Accepted: 29 November 1999     

Surface and wetting characteristics of textured bisphenol‐A based polycarbonate surfaces: Acetone‐induced crystallization texturing methods

Polycarbonate (PC) sheet is a promising material for facile patterning to induce hydrophobic self‐cleaning and dust repelling properties for photovoltaic panels’ protection. An investigation to texture PC sheet surfaces to develop a self‐cleaning structure using solvent induced‐crystallization is carried out using acetone. Acetone is applied in both liquid and vapor states to generate a hierarchically structured surface that would improve its contacts angle and therefore improve hydrophobicity. The surface texture is investigated and characterized using atomic force microscopy, contact angle technique (Goniometer), optical microscopy, ultraviolet‐visible spectroscopy (UV–vis) and Fourier transform infrared spectroscopy. The findings revealed that the liquid acetone‐induced crystallization of PC surface leads to a hierarchal and hydrophobic surface with an average contact angle of 135° and average transmittance <2%. However, the acetone vapor induced‐crystallization results in a slightly hydrophilic hierarchal textured surface with high transmittance; in which case, average contact angle of 89° and average transmittance of 69% are achieved. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43074.     

Synthesis, electrorheology and creep behavior of polyindole/polyethylene composites

In this study, polyindole (PIN) and polyindole/polyethylene (PIN/PE) conducting composites, having various amounts of PIN, were synthesized by chemical polymerization using FeCl₃ as an oxidizing agent and taking the ratio of salt:monomer as 3:1. The samples of PIN and PIN/PE composites were characterized by FTIR, UV–vis, TGA, SEM, Gouy scale magnetic susceptibility, conductivity (1.2 × 10⁻³ S cm⁻¹ > σ > 1.96 × 10⁻⁶ S cm⁻¹, at T = 25 °C) and density measurements. FTIR analysis suggested a 2,3-propagation mechanism for PIN formation. The ground milled samples were subjected to particle size analysis by dynamic light scattering (DLS) and a micron-sized particle distribution was obtained. A series of volume fractions ( = 10–25%) were prepared from the materials in silicone oil (SO) and their sedimentation stabilities determined. The most stable composite [PIN(89%)/PE(11%)] against gravitational sedimentation was subjected to flow-rate measurements under externally applied electric field strength (E) and an electrorheological (ER) activity was observed; threshold energies (E_t) were calculated. The effects of volume fraction, shear rate, external E, frequency and temperature onto ER activities of the suspensions were investigated. Enhancement in the electric field viscosities and shear thinning viscoelastic behaviors were observed for all the samples studied. Recoverable viscoelastic deformations were determined from the creep tests under external E.     

New (κ-C,N)-palladacyclic complexes with benzimidazol-2-ylidene ligand: Synthesis, crystal structures and characterization

Reaction of unsymmetrical benzimidazolium bromides (1) with Ag₂O and subsequent transmetallation with chloro-bridged dinuclear palladacycle, [Pd(dmba)(μ-Cl)]₂ (dmba: N,N-dimethylbenzylamine) afforded benzannulated monocarbene complexes [Pd(dmba)(NHC)Cl], 2. The palladacycles (2a–c) were characterized by elemental analysis; NMR spectroscopy and the molecular structure of 2a and 2c were determined by X-ray crystallography.     

Segmented thermoelectric generator: exponential area variation in leg

The innovative design of segmented thermoelectric generator with exponential area variation is introduced. Thermal efficiency and power output are assessed for various values of the design parameter (a = (L/x) ln[A_a/A(x)], where A_a is constant, and a is the dimensionless geometric parameter, L is the pin length, and A(x) is the pin cross‐sectional area), external load parameter (R_L/R₀, ratio of external electrical resistance to reference electrical resistance), and temperature parameter (θ = T_low/T_high, ratio of cold junction temperature to high junction temperature). The device efficiency obtained is validated through the previous experimental data for various hot and cold junction temperature differences. The findings reveal that thermal efficiency resulted from the current study agrees well with the experimental data. The innovative design of the segmented thermoelectric generator with exponentially decaying pin configuration enhances the thermal efficiency and output power as compared with the device having a single material pin configuration. Increasing temperature ratio results in the reduction in the thermal efficiency and the output power of thermoelectric generator. In addition, lowering the external load parameter improves the thermal efficiency and the output power of the thermoelectric device. The design parameter that maximizes the thermal efficiency of the thermoelectric generator does not maximize the device output power.     

A novel renewable energy-based integrated system with thermoelectric generators for a net-zero energy house

A renewable energy based integrated system is developed to meet the total energy demands of a house located off-grid, and a thermodynamic analysis through energy and exergy methodologies is conducted for analysis, evaluation, and performance assessment. The present novel multigeneration system is mainly driven through the animal residues produced at the farm house. The proposed novel system is composed of nine main units namely, a biomass combustor, photovoltaic (PV) panels, parabolic solar trough collectors, thermoelectric generators, organic Rankine cycle, electrolyzer, homogeneous charged compression ignition (HCCI) engine, absorption chiller, and reverse osmosis (RO) unit. Biomass combustor runs an organic Rankine turbine for additional power during peak loads. The exhaust of gas turbine generates cooling to meet the cooling demand of the residential area of the farm house. PV panels are incorporated to generate hydrogen through electrolyzer. A HCCI engine generates power to compensate peak load as well as charging the farming vehicles of the farm house. The RO unit with energy recovery Pelton turbine produces fresh water for farming and residential use. The advanced integration of subsystems, thermoelectric generators and efficient utilization of waste, improves significant amount of energetic and exergetic efficiencies of overall multigenerational system. The energy and exergy efficiencies are enhanced in the order of 4.8% and 6.3%, respectively, after incorporating innovative cooling system to the PV modules. The overall energy and exergy efficiencies of the proposed multigeneration system with and without thermoelectric are found to be 67.6% and 57.1%, and 68.9% and 58.4%, respectively.     

Monthly variation of total lipid and fatty acid contents of Atlantic bonito,Sarda sarda (Bloch, 1793) of Black Sea

This study represents significant monthly variations of total lipid and fatty acid composition of muscle and liver tissue of Black Sea bonito (P < 0.05). Average total lipids of bonito muscle and liver were 8.4% and 25.1%, respectively, and the highest polyunsaturated fatty acid (PUFA) was observed in September and March as 52.9% and 46.6%, respectively. Bonito muscle was found to contain good amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in a range of 252.0–1169.1 mg/100 g and 712.1–3324.1 g/100 g, respectively. Higher levels were found in liver at 3323.3 mg/100 g for EPA and 6996.5 mg/100 g for DHA. Although 25–100 g edible muscle is necessary to reach 1 g per day of EPA+DHA requirement for a healthy diet, only 9.8–87.9 g of bonito liver is enough to cover the recommended daily amount for these fatty acids. The results indicate that bonito livers constitute a rich and underexploited source of PUFAs.     

Fruit juice–alcohol mixture analysis using machine learning and electronic nose

The aim of this study is to analyze the raw data collected from a fruit juice–alcohol mixture (a fruit juice–alcohol mixture and a fruit juice–multiple alcohol mixture) and the Halal authentication of a fruit juice–alcohol mixture with electronic nose. Machine learning techniques such as naïve Bayesian classifier, K‐nearest neighbors (K‐NN), linear discriminant analysis (LDA), decision tree, artificial neural network (ANN), and support vector machine (SVM) were used to classify the feature of these collected raw data. There are three types of classification: the first one is a fruit juice and an alcohol mixture type; the second is a fruit juice and multiple alcohol mixture types, and the third is a Halal authentication of a fruit juice and alcohol mixture. We aimed at making cocktails with more successful results on the first two types of classification in the work. Also, we focused on Halal authentication of fruit juice–alcohol mixture in the third classification. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.