White graphene based composite proton exchange membrane: Improved durability and proton conductivity

Boron nitride, which is also known as “white graphene” may be an attractive filler for composite proton exchange membrane. Application of polymer electrolyte membranes in fuel cell as an electrolyte is gaining attention due to the requirement of clean energy. However, despite its attractive features it requires more consideration for complete commercialization. Herein we demonstrate the preparation of novel functionalized WHITE GRAPHENE (hexagonal boron nitride) and sulfonated poly ether sulfone (SPES) based polymer electrolyte membranes (PEM). Composite membranes have been characterized through thermal, mechanical, structural analysis. Membranes have been subjected to measure methanol permeability and proton conductivity at different temperatures for its use in DMFC. Composite membranes exhibit good physicochemical properties as well as high methanol crossover resistance. 0.5 wt % of FBN (SP-FBN-05) membrane is found to be adequate to get the better performance in DMFC.     

High performance multi-layer varistor (MLV) from doped ZnO nanopowders by water based tape casting: Rheology,sintering, microstructure and properties

In this work, we report the fabrication of a high performance multi-layer varistor (MLV) via water based tape casting method using novel compositions of nanomaterials. Bi₂O₃, CaO and Co₃O₄ doped ZnO nanopowders were prepared by solution combustion synthesis (SCS) route, calcined at different temperatures (550, 650, 750 and 850?°C) and characterized by TEM, XRD, SEM and AFM. The nanopowder (crystallite size ~30?nm) calcined at 650?°C for 1?h was used as the starting material for MLV fabrication. Compositions of the slurry containing doped ZnO nanopowders, binder and plasticizer in water solvent were optimized for the fabrication of thick film. The rheological properties of the slurries having different solid loadings were analysed and thick films of various thicknesses (50–500?µm) were prepared by varying the feeding rate of tape casting. The film roughness of 38.3?nm for the thick film made from 40?wt% solid slurry was found to be superior compared to other samples due to the presence of reduced crack and shrinkage. MLV fired at 950?°C for 1.5?h exhibited a coefficient of nonlinearity of 18 and breakdown voltage of 291.5?V that yields superior properties compared to commercial MLVs.     

Effect of heating and acidic pH on characteristics of wheat gluten suspension

The effects of different pH treatments with and without heating on the characteristics of wheat gluten suspension was investigated. At pH 1, maximum changes in colour were observed with a concurrent 65% decrease in protein free-thiol content compared to the control gluten. The SDS-Extractability of protein (SDS-EP) chromatogram eluted at lower retention time and the presence of bands at the top lane even during reducing conditions in SDS-PAGE gel suggested complex formation involving bonds other than disulphides. An increase in the free-amino group content and the presence of an additional peak at a higher retention time in the SDS-EP chromatogram was suggestive of hydrolysis. At pH 2 and 3, similar decreases in SDS-EPs and free-thiol content indicated formation of complexes. When heated, the free-thiol content of the dispersions increased compared to the non-heated dispersions indicating disruption of disulphide bonds with changes in gluten structure and size distribution.     

An improved method for R-peak detection by using Shannon energy envelope

R-peaks in electrocardiogram (ECG) play a vital role in diagnosis of heart rhythm irregularities and also estimating heart rate variability. However, almost all existing R-peak detectors suffer from the non-stationary of both QRS morphology and noise. To overcome these difficulties, we propose a four-stage improved method to detect R-peak using Shannon energy envelope. In the first stage, noise is suppressed and QRS complex is enhanced by using band pass filter, first order differentiation, and amplitude normalization. In the second stage, Shannon energy envelope is extracted. In the third stage, peak is estimated without considering any threshold amplitude. In the final stage, true R-peaks are detected. Our proposed R-peak detection method is validated using 48 first channel ECG records of the MIT-BIH arrhythmia database with the accuracy of 99.84%, sensitivity of 99.95% and positive predictability of 99.88%. Our proposed method outperforms other well-known methods in case of pathological ECG signals.     

Computational Fluid Dynamics Modeling for Urea Hydrolysis in a Batch Reactor for Flue Gas Conditioning

A computational fluid dynamics (CFD) model is proposed to simulate urea hydrolysis for ammonia synthesis as a safe feed stock to flue gas conditioning in thermal power plants. A series of parametric studies to investigate flow rates, thermal boundary conditions, and reactor geometry was performed and operating conditions and reactor geometry were optimized. Detailed 3D flow, heat, and chemistry simulations of ammonia were carried out with predicted conversions comparable to measurements and the dependence of the experiments on the reaction parameters was evaluated. Through simulation under the same conditions the output was generated and compared to the experimental plot. Profiles of temperature and flow patterns were successfully achieved through simulation.     

Quaternized poly(phenylene oxide) anion exchange membrane for alkaline direct methanol fuel cells in KOH‐free media

A series of anion exchange membrane (AEM) electrolytes with quaternary ammonium moiety are fabricated from poly (phenylene oxide) for its application in alkaline direct methanol fuel cells (ADMFCs). In the first step, poly(phenylene oxide) (PPO) is successfully chloromethylated by substituting chloromethyl groups in the aryl position of polymer. In the second step, the chloromethylated PPO (CPPO) is further homogeneously quaternized and ion‐exchanged to form an AEM. From the second step, series of AEMs are prepared by changing the mole ratio of amine in relation to CPPO. The presence of quaternary ammonium group in the membrane was confirmed by elemental analysis. The fabricated membranes are subjected to cell polarization studies in ADMFCs, wherein quaternized poly(2,6‐dimethyl‐1,4‐phenylene oxide) (CPPO:amine of 1:8) membrane exhibits higher peak power density of 3.5 mW cm^?2 when compared with the other ratios of CPPO:amine in the absence of KOH solution. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43693.     

Mass transfer kinetics during osmotic dehydration of pomegranate arils

The mass transfer kinetics during osmotic dehydration of pomegranate arils in osmotic solution of sucrose was studied to increase palatability and shelf life of arils. The freezing of the whole pomegranate at -18 °C was carried out prior to osmotic dehydration to increase the permeability of the outer cellular layer of the arils. The osmotic solution concentrations used were 40, 50, 60°Bx, osmotic solution temperatures were 35, 45, 55 °C. The fruit to solution ratio was kept 1:4 (w/w) during all the experiments and the process duration varied from 0 to 240 min. Azuara model and Peleg model were the best fitted as compared to other models for water loss and solute gain of pomegranate arils, respectively. Generalized Exponential Model had an excellent fit for water loss ratio and solute gain ratio of pomegranate arils. Effective moisture diffusivity of water as well as solute was estimated using the analytical solution of Fick's law of diffusion. For above conditions of osmotic dehydration, average effective diffusivity of water loss and solute gain varied from 2.718 × 10(-10) to 5.124 × 10(-10) m(2)/s and 1.471 × 10(-10) to 5.147 × 10(-10) m(2)/s, respectively. The final product was successfully utilized in some nutritional formulations such as ice cream and bakery products.     

Enhanced visible green and 1.5 μm radiative emission of Er~(3+) ions in Li_2O-PbO-Al_2O_3-B_2O_3 glasses for photonic applications

A series of Er~(3+) ions doped lithium lead alumino borate(LiPbAlB) glasses were synthesized via melt quench method and their structural,physical and optical properties were studied.Judd-Ofelt theory in correlation with the emission and absorption profiles was performed for the measurement of various radiative parameters for different transitions of Er~(3+) doped glasses.The as-prepared glasses show deep green(550 nm) as well as NIR(1532 nm) emission at 380 and 980 nm excitation wavelengths,respectively.The intensity of emission spectra increases with Er~(3+) ions concentration up to 1.5 mol% and beyond quenching is observed.The Dexter theory applied to the emission profiles reveals the interaction between Er~(3+)ions as dipole-dipole in nature.CIE color coordinates are found to fall in the green region of the visible spectrum.It is observed that 1.5 mol% of Er~(3+) ions concentration is optimum to exhibit the maximum quantum efficiency,branching ratios,gain bandwidth,emission cross-section,gain crosssection and aptly suitable for visible and NIR photonic applications.