Hydrophilic polymeric membrane supported on silver nanoparticle surface decorated polyester textile: Toward enhancement of water flux and dye removal

A novel mixed matrix nanofiltration membrane was constructed by coating a casting solution containing polyvinylidene fluoride(PVDF), polyethylene glycol(PEG) as hydrophilic agent, zeolitic like framework-67(ZIF-67), ethylenediamine as cross-linking agent on Ag-nanoparticle-decorated polyester textile(PT) support(PT/AgNPs/PVDF-PEG/ZIF-67). PT/Ag-NPs/PVDF-PEG/ZIF-67 morphology, crystalline structure, surface chemical composition and hydrophilicity of PT/Ag-NPs/PVDF-PEG/ZIF-67 were fully characterized by field emission scanning electron microscopy(FE-SEM), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FT-IR) and water contact angle technique, respectively. PT/Ag-NPs/PVDF-PEG/ZIF-67 was applied in cross module set-up for removal of contaminated water containing rose bengal(RB) dye. The effect of operational parameters such as dye concentration,solution pH and flow rate on performance of PT/Ag-NPs/PVDF-PEG/ZIF-67 were investigated and optimized by central composite design(CCD). Casting solution containing 0.5 wt.% ZIF-67 as optimum value showed the good wettability, high pure water flux(PWF; 35.8 L·m~(-2)·h~(-1)), flux recovery ratio(FRR;90%), dye removal efficiency(96.41%). The selectivity factor of 12.72 and 14.42 was found to be for RB in the presence of amido black and methylene blue as interferent dyes, respectively, which showed a good selective recognition ability for RB dye.     

Composites of Semiaromatic Poly(Amide-Ester-Imide) Based on Bioactive Diacid and Oragnomodified Nanoclay Produced by Solution Intercalation Method: Thermal and Morphological Study

The aim of this work was to develop environmental friendly hydrophobic organomodified montmorillonite (OMMT) reinforced poly(amide-ester-imide) (PAEI) composites with enhanced their properties. At first, a chiral PAEI was obtained by step-growth polymerization of diol, N,N’-(1,3,5,7-tetraoxo-5,7-dihydropyrrolo[3,4-f]isoindole-2,6(1H,3H)-diyl)bis(4-hydroxybenzamide) with N-trimellitylimido-L-leucine. The blending of nanoclays with PAEI modifies the thermal property, and this change is strongly related to the dispersion of nanoclay in the polymer matrix. For this goal, positively charged chiral L-leucine was incorporated into the unmodified Cloisite-Na⁺ montmorillonite (MMT) for organomodification of MMT by cation-exchang method. Then PAEI/OMMT nanocomposites with different compositions were synthesized by solution intercalation method.     

Compounding fibre grade polyethylene terephthalate with a hyperbranched additive and studying its dyeability with a disperse dye

A hyperbranched polymer which comprised a polyesteramide structure was used to study improvements in dyeability of fibre grade polyethylene terephthalate films. The optical measurements of the dyed samples showed that, by increasing the percentages of the dendritic additive, K/S as a dye uptake parameter changed in the presence or absence of a carrier. The amount of chroma increased while the hue did not change significantly. The dyeability of the prepared samples was attributed to the decrease in glass transition temperature and the lower crystallinity of the polymer, as studied by differential scanning calorimetry. Thus, a new fibre grade polyethylene terephthalate, which is dyeable, could be obtained, with less need to use a toxic carrier compound.     

A novel hybrid cybersecurity scheme against false data injection attacks in automated power systems

The conventional power systems are evolving as smart grids. In recent times cyberattacks on smart grids have been increasing. Among diferent attacks, False Data Injection (FDI) is considered as an emerging threat that has signifcant impact. By exploiting the vulnerabilities of IEC 61850 Generic Object-Oriented Substation Events (GOOSE) and Sam-pled Values (SV) attackers can launch diferent FDI attacks. In this paper, a real-time set up capable of simulating FDI on GOOSE and SV protocols is developed to evaluate the impact of such attacks on power grid. IEC 62351 stipulates cybersecurity guidelines for GOOSE and SV, but only at communication or Information Technology (IT) level. Hence there is a need to develop a holistic security both at IT and Operation Technology (OT) level. In this regard, a novel sequence content resolver-based hybrid security scheme suitable to tackle FDI attacks on GOOSE and SV is proposed. Furthermore, the computational performance of the proposed hybrid security scheme is presented to demonstrate its applicability to the time critical GOOSE and SV protocols.     

Production of polyvinylpyrrolidone/chiral diacid modified nanocrystalline Mg‐substituted fluorapatite nanocomposites: Morphological and thermal characterization

The main objective of this work was the production of novel polyvinylpyrrolidone/diacid modified Mg‐substituted fluorapatite (DM‐MFA) nanocomposites (NC)s, by sonication process. Mg‐substituted fluorapatite (MFA) powders with a chemical composition of Ca_9.5Mg_0.5(PO₄)₆F₂ were prepared by mechanical alloying technique. Initially, surface of MFA was modified by bioactive chiral diacid monomer, N‐trimellitylimido‐l ‐leucine as a coupling agent to form DM‐MFA nanoparticles. DM‐MFA NPs were utilized as a filler, to give the NCs with potential bioactivity. Examination of transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE‐SEM) microphotographs displayed that, there is no aggregation of a large quantity of particles. The above NCs showed rather improved thermal stability compared with pure polymer. The improvement of thermal behavior was related to the uniform and good dispersion of DM‐MFA in the polymer matrix as well as the strong hydrogen bonding between C?O of PVP and OH of DM‐MFA. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44254.     

Biosynthesis of xanthangum‐coated INPs by using Xanthomonas campestris

Synthesis of iron nanoparticles (INPs) with a biocompatible coating usually is a multistep process which requires harsh, special and protected reaction conditions. In the current experiment, the authors used Xanthomonas campestris cells to develop a facile method for fabrication of biocompatible INPs. Bacterial cells were supplied with ferric citrate as an iron precursor. Transmission electron microscopy micrographs exhibited that xanthan gum‐coated INPs are synthesised and deposited on the surface of X. campestris cells and produced nanoparticles were 20–80 nm in diameter with 41.7 nm mean particle size. Xanthan gum coating with about 7 nm thickness formed a clear hollow around each nanoparticle. According to thermogravimetric analysis, the coating was about 13.4% of the total INPs weight. Prepared particles had a zeta potential of −114 mv which is an ideal surface charge to make particles colloidally stable in aqueous matrixes. Xanthan gum‐coated INPs were non‐crystalline with low saturation magnetisation value of about 0.26 emu/g.Inspec keywords: nanoparticles, nanofabrication, iron, microorganisms, transmission electron microscopy, particle size, electrokinetic effects, surface charging, magnetisation, organic compoundsOther keywords: biosynthesis, xanthan gum‐coated INPs, Xanthomonas campestris cells, iron nanoparticles, biocompatible coating, bacterial cells, ferric citrate, transmission electron microscopy micrographs, mean particle size, thermogravimetric analysis, zeta potential, surface charge, saturation magnetisation, size 20 nm to 80 nm, Fe     

Designing triple-shape memory polymers from a miscible polymer pair through dual-electrospinning technique

Recently, multiple-shape memory polymers (SMPs) have attracted a great deal of attention in biomedical applications. Therefore, a series of triple-SMPs were developed by simply blending of two immiscible SMPs exhibiting two distinct transition temperatures, which is required for triple-shape memory (SM) effect. However, fabrication of triple-SMPs from completely miscible polymer pairs using the conventional blending approach is a challenging problem. Because this type of blends consists of one homogeneous phase and thereby exhibit only one transition temperature and dual-SM behavior. To overcome this problem, herein, a novel and versatile strategy is introduced for preparation of phase separated blends from a completely miscible polymer pair, exhibiting triple-SM behavior. Dual-electrospinning technique was utilized to simultaneously electrospin poly(lactic acid) (PLA) and poly(vinyl acetate) (PVAc), as a model miscible polymer pair, to obtain an interwoven polymer composite with two well-separated thermal transitions, as revealed by dynamic mechanical analyze. Consequently, the SM experiments revealed that the electrospun PLA/PVAc composites have triple-SM behavior. Furthermore, incorporation of graphene nanoplatelets into the composite fibers significantly improved the triple-SM properties of samples. Additionally, excellent adherence and spreading of the osteoblasts on the fibrous scaffolds containing graphene were observed. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47471.     

Improved field emission properties of ZnO NRs using Al-doped and post oxygen annealing

Microsystem Technologies - In this paper, we synthesized Al doped ZnO (AZO) nanorods (NRs) and characterized their field emission properties. In addition, we considered the effect of post annealing...     

Heat transfer and fluid flow modeling in serpentine microtubes using adaptive neuro-fuzzy approach

An adaptive neuro-fuzzy inference system (ANFIS) is applied to predict thermal and flow characteristics in serpentine microtubes. Heat transfer rate and pressure drop were experimentally measured for six serpentine microtubes with different geometrical parameters. Thermal and flow characteristics were obtained in various flow conditions. The ANFIS models were trained using the experimental data to predict Nusselt number (Nu) and friction factor (f) in the studied serpentine microtubes as a function of geometric parameters and flow conditions. The model was validated through testing data set, which were not previously introduced to the developed ANFIS. For Nu prediction, the root mean square error (RMSE), mean relative error (MRE), and absolute fraction of variance (R²) between the predicted results and experimental data were found 0.2058, 1.74%, and 0.9987, respectively. The corresponding calculated values for f were 0.0056, 2.98%, and 0.9981, respectively. The prediction accuracy of the ANFIS models was compared with that of corresponding classical power-law correlations and its advantages are illustrated.