Crosslinked PVDF-HFP-based hydrophobic membranes incorporated with CNF for enhanced stability and permeability in membrane distillation

Over the past decades, numerous materials have emerged as promising amenities for the fabrication of novel membranes. The current study gives insight into a modest and effective method to fabricate a crosslinked poly-vinylidene fluoride-co-hexafluoropropylene membrane with better mechanical properties and permeability for desalination. Poly-vinylidene fluoride-co-hexafluoropropylene membrane was grafted with crosslinked collagen to enhance direct contact membrane distillation used for desalination. Stiffness, rigidity and mechanical properties of the membrane were intensified by incorporating collagen (extracted from eggshells) into the membrane matrix, with glutaraldehyde crosslinkers. Furthermore, to improve water vapor diffusion, immobilized carbon nanofibers (CNF) were integrated in the membrane, casted via phase inversion technique with an optimized controlled approach. The permeate flux of CNF incorporated membrane was as high as 8 LMH, 18% higher than the unmodified poly-vinylidene fluoride-co-hexafluoropropylene membrane at 60 °C, besides minimal salt leakage. The properties of the modified membrane were characterized from its contact angle, morphological structure, surface roughness, dynamic mechanical properties, and water flux. The overall performance of the modified membranes was better than the virgin membranes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48021.     

Flow behaviour of autoclaved, 20% cold worked, Zr-2.5Nb alloy pressure tube material in the temperature range of room temperature to 800 °C

Pressure tube material of Indian Heavy Water Reactors is 20% cold-worked and stress relieved Zr-2.5Nb alloy. Inherent variability in the process parameters during the fabrication stages of pressure tube and also along the length of component have their effect on micro-structural and texture properties of the material, which in turn affect its strength parameters (yield strength and ultimate tensile strength) and flow characteristics. Data of tensile tests carried out in the temperature range from room temperature to 800 °C using the samples taken out from a single pressure tube have been used to develop correlations for characterizing the strength parameters’ variation as a function of axial location along length of the tube and the test temperature. Applicability of Ramberg-Osgood, Holloman and Voce’s correlations for defining the post yield behaviour of the material has been investigated. Effect of strain rate change on the deformation behaviour has also been studied.     

Synthesis, structure and dielectric properties of a rare earth double perovskite oxide Ba2CeTaO6

A rare earth double perovskite oxide barium cerium tantalate, Ba₂CeTaO₆ (BCT) is synthesized by solid-state reaction. The X-ray diffraction pattern of the sample at room temperature (25 °C) shows monoclinic structure, with the lattice parameters, a = 9.78 Å, b = 9.02 Å and c = 4.27 Å and β = 93.8°. A scanning electron micrograph shows the formation of grains with average size ∼ 2 μm. Impedance spectroscopy is applied to investigate the ac electrical properties of BCT in a temperature range from 303 to 673 K and in a frequency range from 100 Hz to 1 MHz. Complex-impedance-plane plots show grain contribution for BCT. The frequency-dependent electrical data are analyzed in the framework of the conductivity and modulus formalisms. The frequency-dependent conductivity spectra follow a power law. The conductivity at 110 Hz varies from 3.5 × 10⁻⁷ S m⁻¹ to 1.2 × 10⁻² S m⁻¹ with increasing temperature from 303 to 673 K, respectively. The scaling behaviour of M″ and Z″ suggest that the relaxation describes the same mechanism at various temperatures.     

Performance Analysis and FPGA Prototype of Variable Rate GO-OFDMA Baseband Transmission Scheme

Wireless Personal Communications - To fulfill the increasing demand for high speed Variable Bit Rate (VBR) broadcast services with reliable Quality of Service, Group Orthogonal-Orthogonal Frequency...     

Ultra-high-molecular-weight polyethylene reinforced polypropylene and polyamide composites toward developing low-noise automobile interior

Circular ultra-high-molecular-weight polyethylene (UHMWPE) of 60 and 140 μm particle size, to ensure the homogenous mixing, was used as filler materials for developing the polypropylene (PP) and polyamide 6 (PA6)-based composite specimens to investigate the effect of UHMWPE on reducing the noise, if the composites are used in car interior. PP composite containing 5 wt % UHMWPE of 60 μm particle size showed the lowest in-plane friction coefficient (0.18 ± 0.01), improved Izod impact strength (33 ± 2.9 J/m²), and considerable tensile properties (37 ± 1.5 MPa of strength and 21 ± 1.1% of elongation at break), indicating its promise as low-noise and durable material to be used in the car interior. Although PA6 composites showed decreasing friction coefficients with increasing UHMWPE content, their tensile and impact properties became poor or inconsistent, maybe due to the incompatibility of nonpolar UHMWPE with polar PA, and the large difference of their melting temperatures. The extent of compatibility of PP and PA6 with the UHMWPE has been investigated by analyzing the morphology (using scanning electron microscope) and the thermal properties of the composites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48720.     

Effect of hydrophilic poly(ethylene glycol) methyl ether additive on the structure,morphology, and performance of polysulfone flat sheet ultrafiltration membrane

In this work, effects of hydrophilic poly(ethylene glycol) methyl ether (PEGME) 5000 additive on the structure, morphology, and performance of polysulfone (PSF) membrane have been investigated. The membranes are prepared with direct blending of PEGME5000 (0–9 wt %) with two compositions of PSF (12 and 15 wt %) into N-methyl-2-pyrrolidone and further characterized in terms of morphology, structure, fouling, and ultrafiltration performance. The ternary phase diagram is plotted to investigate the thermodynamic stability of the system. Moreover, protein adsorption tests are conducted using bovine serum albumin (BSA) to see the effect of PEGME5000 on surface hydrophilicity. The ultrafiltration experiments are performed using humic acid (HA) solution and oil-in-water (o/w) emulsion. The result showed that, the contact angle decreased from 64° to 46° and from 67.6° to 49° for 12M and 15M membranes, respectively, indicating an improved hydrophilicity. The 12M and 15M membranes with 9 wt % of PEGME5000 have the lowest BSA adsorption due to highest antifouling property. The maximum permeability was obtained 0.72 and 0.51 L/m² h kPa for 12M5 and 15M3, respectively, due to maximum porosity which is also supported by the morphological result. In HA permeation, 12M5 and 15M3 achieved a maximum Flux _RR around 0.95 and 0.91, respectively, which was remarkably higher compared to 0.61 and 0.62 Flux _RR of 12M0 and 15M0. Also, PEGME5000 significantly affected the structure and morphology of the membranes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47163.     

FLASc: a formal algebra for labeled property graph schema

Automated Software Engineering - Mailing lists are a major communication channel for supporting developer coordination in open-source software projects. In a recent study, researchers explored...     

Effect of external stimulus on polymer conformation in CdS-PVP nanocomposites: Raman,PL, and AFM mapping study

Journal of Materials Science - Intriguing spherical conformation of polyvinyl pyrrolidone (PVP) embedded with CdS nanocrystals in CdS-PVP nanocomposites grown via facile chemical bath deposition is...     

Polyphenol oxidase-based luminescent enzyme hydrogel: an efficient redox active immobilized scaffold

A novel, functionally potent polyphenol oxidase (10000 U)-mediated urchin-shaped composite-based luminescent enzyme hydrogel network as immobilized scaffold for oxido-reductase efficiency on phenolic substrates including phenol, resorcinol, catechol and quinol was synthesized and characterized through fluorescence spectroscopy along with scanning electron microscopy and transmission electron microscopy.     

Enzymatically crosslinked carboxymethyl–chitosan/gelatin/nano-hydroxyapatite injectable gels for in situ bone tissue engineering application

Present study reports synthesis and characterization of an enzymatically crosslinked injectable gel (iGel) suitable for cell based bone tissue engineering application. The gel comprises of carboxymethyl–chitosan (CMC)/gelatin/nano-hydroxyapatite (nHAp) susceptible to tyrosinase/p-cresol mediated in situ gelling at physiological temperature. Study revealed that a combination of tyrosinase (60U) and p-cresol (2 mM) as crosslinking agents yield rigid gels at physiological temperature when applied to CMC/gelatin within 35 min in presence or absence of nHAp. Rheological study in conjugation with FT-IR analysis showed that an increase in CMC concentration in the gel leads to higher degree of crosslinking and higher strength. Scanning electron microscopy showed that pore sizes of iGels increased with higher gelatin concentration. In vitro study of osteoblast cell proliferation and differentiation showed that, although all iGels are supportive towards the growth of primary osteoblast cells, GC1:1 supported cellular differentiation to the maximum. Application of iGels in mice revealed that stability of the in situ formed gels depends on the degree of crosslinking and CMC concentration. In conclusion, the iGels may be used in treating irregular small bone defects with minimal clinical invasion as well as for bone cell delivery.