New Blue Light Emissive Polyazomethine(S) Containing Bromo-Triphenyl Units: Synthesis and Photophysics

A series of bromo-substituted triphenylamine based poly(azomethine)s (P1-P3) were synthesized from the N¹-(4-aminophenyl)-N¹-(4-bromophenyl)benzene-1,4-diamine (DA) and aromatic dialdehydes. The viscosity of P1-P3 solutions (0.97 to 1.12 g dL^?1) and molecular weight distribution analysis by Gel Permeation Chromatography (GPC) discloses the attainment of appreciable molecular weight. The optical transparency and fluorescence properties of the P1-P3 were explored by UV-vis and photoluminescence spectral analysis. From which it was concluded that the presence of 4-bromotriphenylamine and azomethine (CH = N) linkage in our synthesized materials are possibly responsible for the fluorescence with quantum efficiencies of 0.9–2.1 %.     

Extraction and quantification of phenolic compounds from <Emphasis Type="Italic">Prunus armeniaca</Emphasis> seed and their role in biotransformation of xenobiotic compounds

The current research project has been devoted to isolating new low cost and eco-friendly phenolic compounds from fruit seeds, peels and vegetables to reduce the atmospheric pollution. Natural phenolic compounds were extracted from different fruit seeds and agriculture waste: P. armeniaca, P. persica, P. domestica and Triticum aesativum. The total phenolic content was quantified, and the maximum value (1 mL extract having 1,933 μg) was found in P. armeniaca seed extract. Phytochemical screening showed that P. armeniaca seeds contain higher amount of alkaloid, tannins, saponins and flavonoid. P. armeniaca seeds enhanced the biotransformation of reactive yellow dye up to 69.89% with maximum laccase (322.45 IU/mL) production. Biodegradation of reactive yellow was only 23.34% without natural redox mediator at sixth day of incubation. Use of P. armeniaca seed stimulators resulted in maximum laccase activity (894.4 IU/mL) with 99.5% rate of removal. UV-Vis, HPLC & FTIR analysis confirmed the transformation of parent dye into various new products. Phytotoxicity study indicated 0% germination index of Avena sativa seeds with reactive yellow, whereas 83% germination index having 100% seed germination while 83% root elongation with treated sample. Thus, the study revealed that the natural phenolic compounds could serve as high potential redox mediators for enhanced laccase-mediated decolorization of reactive yellow dye.     

Biometric signature authentication using machine learning techniques: Current trends,challenges and opportunities

Multimedia Tools and Applications - Biometric systems are playing a key role in the multitude of applications and placed at the center of debate in the scientific research community. Among the...     

A new dual CUSUM mean chart

The conventional cumulative sum (CUSUM) chart is usually designed based on a known shift size. In usual practice, shift size is often unknown and can be assumed to vary within an interval. With such a range of shift size, the dual CUSUM (DCUSUM) chart provides more sensitivity than the CUSUM chart. In this paper, we propose dual Crosier CUSUM (DCCUSUM) charts with and without fast initial response features to efficiently monitor the infrequent changes in the mean of a normally distributed process. Monte Carlo simulations are used to compute the run length characteristics of one‐sided and two‐sided DCCUSUM charts. These run length characteristics are compared with those of the CUSUM, Crosier CUSUM, Shewhart‐CUSUM, and DCUSUM charts in terms of the integral relative average run length. It turns out that the proposed chart shows better performance when detecting a range of mean shift sizes. A real dataset is considered to illustrate the implementation of existing and proposed charts.     

Supercritical fluid technology parameters affecting size and behavior of stereocomplex polylactide particles and their composites

Polylactide (PLA) is a eco‐friendly and biodegradable material that can be synthesized from renewable resources. PLA features poly(d ‐lactic acid) (PDLA) and poly(l ‐lactic acid) (PLLA) enantiomers. Supercritical fluid (SCF) technology is a very promising method for the stereocomplexation between PDLA and PLLA enantiomers. This study acquires stereocomplex (sc‐)PLA particles with diverse sizes and behaviors by controlling the experimental conditions. Various parameters including polymer concentration, reaction temperature, stirring speed, pressure reducing speed, and final temperature were controlled to adjust size and behavior of sc‐PLA particles. Additionally, we analyzed the effect of subsequent processing following SCF (such as homogenization, mechanical stirring, and sonication) on the size and morphological behavior of sc‐PLA particles. Finally, the mechanical strengths of different PLA composites featuring different sc‐PLA filler sizes were determined. The mechanical strength of PLA composites was significantly improved when using smaller filler sizes. POLYM. ENG. SCI., 58:1193–1200, 2018. © 2017 Society of Plastics Engineers     

Structural characterization of TiN coatings on Si substrates irradiated with Ar ions

The present study deals with TiN/Si bilayers irradiated at room temperature (RT) with 120 keV Ar ions. The TiN layers were deposited by d.c. reactive sputtering on Si(100) wafers to a thickness of ～ 240 nm. After deposition the TiN/Si bilayers were irradiated to the fluences of 1 × 10¹⁵ ions/cm² and 1 × 10¹⁶ ions/cm². Structural characterization was performed with Rutherford backscattering spectroscopy (RBS), cross-sectional transmission electron microscopy (XTEM), grazing angle X-ray diffraction (XRD) and atomic force microscopy (AFM). The results showed that the variation of the lattice constants, mean grain size and micro-strain can be attributed to the formation of the high density damage region in the TiN film structure. It has been found that this damage region is mainly distributed within ～ 100 nm at surface of the TiN layers.     

Clear Skies Ahead: Towards Real‐Time Automatic Sky Replacement in Video

Digital videos such as those captured by a smartphone often exhibit exposure inconsistencies, a poorly exposed sky, or simply suffer from an uninteresting or plain looking sky. Professionals may edit these videos using advanced and time‐consuming tools unavailable to most users, to replace the sky with a more expressive or imaginative sky. In this work, we propose an algorithm for automatic replacement of the sky region in a video with a different sky, providing nonprofessional users with a simple yet efficient tool to seamlessly replace the sky. The method is fast, achieving close to real‐time performance on mobile devices and the user's involvement can remain as limited as simply selecting the replacement sky.     

Electro-catalyst [ZrO2/ZnO/PdO]-NPs green functionalization: Fabrication,characterization and water splitting potential assessment

Present investigation reports the biomimetic synthesis of mixed metallic oxides nanoparticles (NPs) comprising of zirconia, zinc oxide and palladium oxide ([ZrO₂/ZnO/PdO]-NPs) functionalized via nature's bio-factories for the first time. [ZrO₂/ZnO/PdO]-NPs express reduction revealed via Fourier transform infra-red spectroscopy and gas chromatography and mass spectrometry. X-ray diffraction express poly-crystallinity. The fabrication of green NPs is confirmed via energy-dispersive X-ray spectroscopy with irregular morphologies visible by scanning electron micrographs. A direct bandgap of 2.11 eV is obtained for [ZrO₂/ZnO/PdO]-NPs. Promising surficial features are disclosed via X-ray photoelectron spectroscopy. The electro-catalytic potential is studied using linear sweep voltammetry and electrochemical impedance spectroscopy for investigation of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activities with low over-potential of 0.37 V and Tafel slope of 74 mV/dec, indicating the suitability for OER. [ZrO₂/ZnO/PdO]-NP electro-catalyst is also tested for HER, demonstrating remarkable results with the overpotential and Tafel slope value of 157 mV and 151 mV/dec.     

An Effective Numerical Method for the Solution of a Stochastic Coronavirus (2019-nCovid) Pandemic Model

Nonlinear stochastic modeling plays a significant role in disciplines such as psychology, finance, physical sciences, engineering, econometrics, and biological sciences. Dynamical consistency, positivity, and boundedness are fundamental properties of stochastic modeling. A stochastic coronavirus model is studied with techniques of transition probabilities and parametric perturbation. Well-known explicit methods such as Euler Maruyama, stochastic Euler, and stochastic Runge–Kutta are investigated for the stochastic model. Regrettably, the above essential properties are not restored by existing methods. Hence, there is a need to construct essential properties preserving the computational method. The non-standard approach of finite difference is examined to maintain the above basic features of the stochastic model. The comparison of the results of deterministic and stochastic models is also presented. Our proposed efficient computational method well preserves the essential properties of the model. Comparison and convergence analyses of the method are presented.     

Enhanced EWMA charts for monitoring the process coefficient of variation

The coefficient of variation (CV) is an important quality characteristic when the process variance is a function of the process mean for a production process. In this paper, we develop an auxiliary information–based (AIB) estimator for estimating the squared CV, along with its approximated mean and variance. This estimator is then used to devise new one-sided EWMA charts for monitoring the increases or decreases in the squared CV of a normal process, named the AIB-EWMA CV charts. In addition, the sensitivities of these control charts are also enhanced with the fast initial response feature. The Monte Carlo simulation method is used to compute the run length characteristics of the proposed CV charts. Based on detailed run length comparisons, it is found that the proposed AIB-EWMA CV charts are uniformly and substantially better than the existing EWMA CV charts when detecting different kinds of upward/downward shifts in the squared CV. The proposed charts are also applied to a real dataset to support the proposed theory.