Polypropylene/phosphazene nanotube nanocomposites: Thermal,mechanical, and flame retardation studies

In this study, flame retardant polypropylene (PP) nanocomposites with superior mechanical performance have been developed using amine-functionalized phosphazene nanotubes (APZS, 1–10 wt%) through melt-blending method. Polypropylene-graft-maleic anhydride was used as the compatibilizer to attain effective interaction between the nanofiller and the PP matrix. The characterization of amine-functionalized phosphazene nanotubes (APZS) using solid-state nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy, X-ray diffraction, fourier-transform infrared (FTIR), and transmission electron microscopy indicated successful amine functionalization, though structural changes were observed as compared to the unfunctionalized nanotubes. Owing to the covalent polymer-filler interfacial interactions and resulting in uniform filler dispersion, the nanocomposites exhibited significant enhancement in the tensile modulus up to 5 wt% APZS content (98% increment at 5 wt% content as compared to pure polymer). The addition of a small fraction of APZS (1 wt%) improved the impact strength of the nanocomposite by more than 180%. APZS acted as a weak nucleating agent for PP, thereby leading to enhanced degree of crystallinity (up to 5 wt% APZS content). The thermal stability of the nanocomposites was also enhanced with APZS content. The nanocomposites with 5 and 10 wt% APZS loading exhibited a V0 rating in UL-94 test, indicating that APZS introduced a robust flame retardancy behavior in the PP nanocomposites. The limiting oxygen index values also confirmed the findings from the UL-94 analysis. The developed nanocomposites exhibit high potential of use in a wide range of high temperature applications.     

Study of the lightfastness properties of prints on blister foils by spectral reflectance

This study describes the lightfastness properties of printed foil samples due to long-time exposure. Lightfastness is an important property for any kind of print products to assess their print stability. The fastness properties of prints can be described in terms of print durability and image stability. It may also be used for verification of printed expiry date and authenticity or validity of the product. Moreover, any kind of deterioration in package print quality will affect the product's sale adversely. Little work has been conducted to study the fastness properties of printed films and foils. In this work, blister foils printed in the gravure printing process have been taken as the sample as they have extensive usage in food and medicine packaging. An artificial lightfastness tester BGD 865/A Bench Xenon Test Chamber (B-SUN) is used to study the light fastness of Cyan, Magenta, Yellow, and Black inks on the foil. The spectral curves and colorimetric values are measured using an Ocean Optics Spectroradiometer (DH2000BAL) before and after exposure. A kinetic model is proposed to predict the fading rate of the printed foil. The optimal model has given excellent prediction with a correlation coefficient of 0.90 to 0.93 for Cyan, Magenta, Yellow, and Black prints, respectively. The largest color difference ΔE₀₀ is achieved for Yellow print followed by Magenta. Cyan and Black prints have shown small changes with time when the gravure prints are exposed to the artificial aging chamber.     

Airborne viable, non-viable, and allergenic fungi in a rural agricultural area of India: a 2-year study at five outdoor sampling stations

The information on airborne allergenic fungal flora in rural agricultural areas is largely lacking. Adequate information is not available to the bioaerosol researchers regarding the choice of single versus multiple sampling stations for the monitoring of both viable and non-viable airborne fungi. There is no long-term study estimating the ratios of viable and non-viable fungi in the air and earlier studies did not focus on the fractions of airborne allergenic fungi with respect to the total airborne fungal load. To fill these knowledge gaps, volumetric paired assessments of airborne viable and non-viable fungi were performed in five outdoor sampling stations during two consecutive years in a rural agricultural area of India. Samples were collected at 10-day intervals by the Burkard Personal Slide Sampler and the Andersen Two-Stage Viable Sampler. The data on the concentrations of total and individual fungal types from five stations and 2 different years were analyzed and compared by statistical methods. The allergenicity of the prevalent airborne viable fungi was estimated by the skin-prick tests of >100 rural allergy patients using the antigenic fungal extracts from isolates collected with the Andersen sampler. The ranges of total fungal spore concentration were 82-2365 spores per cubic meter of air (spores/m3) in the first sampling year and 156-2022 spores/m3 in the second sampling year. The concentration ranges of viable fungi were 72-1796 colony-forming units per cubic meter of air (CFU/m3) in the first sampling year and 155-1256 CFU/m3 in the second sampling year. No statistically significant difference was observed between the total spore data of the 2 years, however, the data between five stations showed a significant difference (P<0.0001). No statistically significant difference existed between stations and years with respect to the concentration of viable fungi. When the data of individual allergenic fungal concentrations were compared between stations and years, no statistically significant difference was observed in all cases except for Aspergillus japonicus and Rhizopus nigricans, which showed significant difference in case of stations and years, respectively. The ratios between the total fungal spores collected by the Burkard sampler and the viable fungi collected by the Andersen sampler from all sampling stations ranged between 0.29 and 7.61. The antigenic extracts of eight prevalent viable airborne fungi (A. flavus, A. japonicus, A. fumigatus, Alternaria alternata, Cladosporium cladosporioides, Curvularia pallescens, Fusarium roseum, and R. nigricans) demonstrated >60% positive reactions in the skin prick test. These selected allergenic fungi collectively represented 31.7-63.2% of the total airborne viable fungi in different stations. The study concluded that: (i) a rich fungal airspora existed in the rural study area, (ii) to achieve representative information on the total airborne fungal spores of an area, the monitoring in multiple sampling stations is preferable over a single sampling station; for viable fungi, however, one station can be considered, (iii) the percentage of airborne fungal viability is higher in rural agricultural areas, and (iv) approximately 52% of the viable airborne fungi in the rural study area were allergenic.     

Bio-Inorganic Studies on the Fe(II) Sparfloxacin Complex

The qualitative and quantitative analysis of an antibiotic drug, 5-amino-1 cyclopropyl-7 (cis-3, 5 dimethyl-1-piperazyl)-6,8- dihydro-1, 4 dihydro-4-oxo-3-quinoline carboxylic acid (Sparfloxacin, SFX) and its pharmaceutical formulation i.e.sparx-100 tablet, has been done using polarographic and amperometric methods. Complexation behavior of SFX with Fe(II), both in solid and liquid phases has been studied by elemental analysis, IR.-spectra and polarographic and amperometric methods. SFX produces a single cathodic reduction wave in 0.1 M ammonium tartrate (supporting electrolyte) at pH 6.0 +/-0.1. The wave is diffusion controlled and wave height is proportional to the concentration of SFX. The complex is also reversibly reduced at the electrode surface with diffusion-controlled kinetics. The stoichiometry of the Fe(II)- SFX complex is 1:1. Antibacterial studies on the drug and its metal complex have been performed against different bacteria. The observed results revealed the complex to be more potent in its antibacterial activity as compared to the parent drug. On the basis of observed results it could be concluded that the prepared Fe(II)- SFX complex may be recommended to the therapeutic experts for its possible use as a more potent antibiotic drug.     

Design of a frequency spectrum-based versatile two-dimensional arbitrary shape filter bank: application to contact lens detection

Pattern Analysis and Applications - A filter bank (FB) is an integral part of any image processing system. The designing of a FB generally involves modifying an existing FB or focusing on a...     

Heat transfer analysis for unsteady MHD flow past a non-isothermal stretching surface

An analysis is made for the unsteady two-dimensional magneto-hydrodynamic flow of an incompressible viscous and electrically conducting fluid over a stretching surface having a variable and general form of surface temperature which removes the restrictions of the particular forms of prescribed surface temperature. Similarity solutions for the transformed governing equations are obtained. The transformed boundary layer equations are solved numerically for some values of the involved parameters, namely the unsteadiness parameter, magnetic parameter, the temperature exponent parameters. The features of the flow and heat transfer characteristics for different values of the governing parameters are analysed and discussed. It is found that the fluid velocity and temperature decrease for increasing unsteadiness parameter. Fluid velocity decreases with the increasing values of the Hartman number resulting an increase in the temperature field in steady as well in unsteady case. It is observed that the variation of the sheet temperature in respect of distance and time has analogous effects both on the free surface temperature and on the heat transfer rate (Nusselt number) at the sheet.     

ONIOM Study for Selectivity of Extractants for Extraction of Rare‐Earth Metals

A hybrid molecular modelling technique, the ONIOM method, has been used to study the selectivity of various extractants for the extraction of La³⁺ and Nd³⁺. MM calculations have been done for the environmental system, whereas DFT calculation has been carried out for the model system. The total ONIOM energy of the metal‐ligand complexes was calculated and the selectivity of La³⁺ and Nd³⁺ for D2EPHA, Cyanex 272 as well as PC88A determined based on the interaction energy. The lower energy for Nd complexes compared to La complexes for all three extractants shows preference of Nd over La. The ONIOM calculations infer the stability of the metal complexes in the order of D2EPHA >PC88A >Cyanex 272, which agrees well with the experimental results for both metal ions.     

Dramatic Improvement in Ionic Conductivity and Water Desalination Efficiency of SGO Composite Membranes

Energy efficient membranes of SGO (Sulfonated Graphene Oxide) into SPES (Sulfonated Polyethersulfone) matrix have been prepared containing different weight content of SGO. Proton conductivity and water retention capacity of membranes increases by increasing SGO while degree of swelling decreases. TEM micrograph shows the uniform distribution of SGO throughout the membrane. SGO-5 membrane shows the maximum proton conductivity (5.8 x 10^?2 S/cm), which is almost double to the SPES with higher stability. SGO-5 membrane shows 4.73 mole.m^?2h^?1 ionic flux, 0.98 kWhkg^?1 power consumption and 93.1% current-efficiency for salt removal, which are 62% and 15.2% higher, respectively, while 16% lower power consumption is observed as compared to SPES.     

One platform comparison of solubilization potential of dendrimer with some solubilizing agents

Objective: To compare various solubilizing agents for their solubilizing propensity as well as effect of pH, concentration and time on solubility of a highly hydrophobic drug.

Materials and methods: Dendrimers were synthesized by divergent method. Solubilization studies were carried out at different pH, concentration and time using Paclitaxel (PTX) as model drug. Hemolytic toxicity study was also performed.

Results: The solubility of PTX was increased with increasing concentration of solubilizing agents and the order of solubility enhancement effect of different solubilizing agents was found to be in the following order: fifth generation (5.0?G) poly(propylene imine) (PPI) dendrimers?>?β-CD?>?Tween 80?>?polyethylene glycol 6000. The solubility of PTX was found to be highest at pH 5.0 followed by pH 7.4 than pH 9.2. The result of hemolytic toxicity studies displayed that when these solubilizing agents are given in combination with PTX, the toxicity was found to be reduced as compare to plain drug.

Conclusions: The solubility of PTX was found to be significantly higher in the presence of 5.0?G PPI dendrimers as compared to the other solubilizing agents. It is also concluded that 5.0?G PPI dendrimers not only enhanced the solubility of PTX many folds but also reduced the toxicity of PTX.