Enhanced alkali vapor attack resistance of bauxite-SiC refractories for the working lining of cement rotary kilns via incorporation of andalusite

Bauxite-SiC refractories as the working lining of cement rotary kiln are subjected to severe alkali attack due to alternative fuel combustion. Herein, the present work aims to enhance their alkali attack resistance via incorporation of different types of andalusite (aggregates and powder). Results show that addition of andalusite reduces penetration of alkali vapor by decreasing their pore size. In particular, the presence of andalusite aggregate traps alkali vapor inside its pore network, retarding the corrosion of refractory matrix. By comparison, the presence of andalusite powder contributes to formation of liquid corrosion products to block the pores, which prevent alkali vapor from further penetration. Incorporation of andalusite into BSRs is straightforward and sought-after, providing an effective approach for high-performance refractory materials with excellent alkali attack resistance.     

Valorization of fish byproducts: Sources to end-product applications of bioactive protein hydrolysate

Fish processing industries result in an ample number of protein-rich byproducts, which have been used to produce protein hydrolysate (PH) for human consumption. Chemical, microbial, and enzymatic hydrolysis processes have been implemented for the production of fish PH (FPH) from diverse types of fish processing byproducts. FPH has been reported to possess bioactive active peptides known to exhibit various biological activities such as antioxidant, antimicrobial, angiotensin-I converting enzyme inhibition, calcium-binding ability, dipeptidyl peptidase-IV inhibition, immunomodulation, and antiproliferative activity, which are discussed comprehensively in this review. Appropriate conditions for the hydrolysis process (e.g., type and concentration of enzymes, time, and temperature) play an important role in achieving the desired level of hydrolysis, thus affecting the functional and bioactive properties and stability of FPH. This review provides an in-depth and comprehensive discussion on the sources, process parameters, purification as well as functional and bioactive properties of FPHs. The most recent research findings on the impact of production parameters, bitterness of peptide, storage, and food processing conditions on functional properties and stability of FPH were also reported. More importantly, the recent studies on biological activities of FPH and in vivo health benefits were discussed with the possible mechanism of action. Furthermore, FPH-polyphenol conjugate, encapsulation, and digestive stability of FPH were discussed in terms of their potential to be utilized as a nutraceutical ingredient. Last but not the least, various industrial applications of FPH and the fate of FPH in terms of limitations, hurdles, future research directions, and challenges have been addressed.     

Enhanced mechanical properties of lightweight Al2O3-C refractories reinforced by combined one-dimensional ceramic phases

We prepared a new lightweight Al₂O₃-C refractory material with a higher strength by using microporous corundum aggregates instead of dense tabular corundum aggregates, which was reinforced by in situ formed SiC whiskers, multi-walled carbon nanotubes (MWCNTs), and mullite rods. A comparative study of the microstructure, mechanical properties, and fracture behavior was carried out for dense and lightweight Al₂O₃-C refractories coked at 1200°C and 1400°C, respectively. By using the microporous corundum aggregates, a better aggregate/matrix interface bonding and an optimized distribution of SiC whiskers were obtained. The SiC whiskers formed inside the microporous corundum aggregates and simultaneously in the matrix by a vapor-solid reaction mechanism, resulting in an enhancement at the microporous aggregate/matrix interface. Furthermore, the in situ formed MWCNTs and well-developed mullite rods at 1200°C in the matrix also contributed to the better interface structure. Thus, due to the improved microporous aggregate/matrix interface, the crack propagation along the aggregate/matrix interface was suppressed, resulting in an increased crack propagation within the aggregates. Consequently, the synergy between microporous corundum aggregates and combined one-dimensional ceramic phases caused a lower bulk density but a markedly higher strength, a higher fracture energy, and a higher toughness of lightweight Al₂O₃-C refractories compared to the dense ones. Overall, our study allows to overcome the traditional concept that a higher strength of refractories is reached by a higher density.     

A deep multimodal system for provenance filtering with universal forgery detection and localization

Multimedia Tools and Applications - Traditional multimedia forensics techniques inspect images to identify, localize forged regions and estimate forgery methods that have been applied. Provenance...     

A new route of cross-linking of carboxylated acrylonitrile-butadiene rubber via zinc oxide-amino acid network formation

Herein, we present a strategy that leads to the formation of a high-performance elastomeric material based on the carboxylated acrylonitrile-butadiene rubber (XNBR). A unique cross-linking route for XNBR has been designed, which does not involve typical cross-linking agents such as sulfur. In this study, the show cause-effect of zwitterionic compounds as the secondary cross-linking agent for ionic elastomer has been investigated. Naturally occurring lysine (Ly) and tryptophan (Trp) amino acid are the zwitterionic compounds, which have been explored here. This approach results in the formation of a cross-linked ionic elastomer that houses a dual ionic network structure formed by zinc oxide (ZnO) and amino acid. XNBR cross-linked by ZnO and different amino acid compounds exhibit superior physical properties as compared to the conventional cross-linking system. Fourier transform infrared spectroscopy, transmission electron microscope, and swelling study analyzes confirm the existence of zinc-carboxylate and zwitterionic network in XNBR after the cross-linking process. The dynamic mechanical analysis, differential scanning calorimetry, and oscillating disk rheometer analyzes show various thermal relaxations and transitions present in the dual cross-linked XNBR. The ZnO and amino acid cross-linked XNBR rubber with 2.5 phr of Ly and 5 phr of Trp show the highest tensile strength of 42.4 and 39.7 MPa, respectively, which is mostly higher than the previously reported values for ionic cross-linked elastomers.     

Quantum and dielectric confinements of sub-10 nm gold in dichroic phosphate glass nanocomposites

Blue shifts of the surface plasmon resonance band of sub-10 nm gold in dichroic phosphate glass nanocomposites are observed with increase in both size of gold nanoparticles and refractive index of the medium, which are contrary to the common trends. These phenomena have been enlightened with the electrodynamics theories (Mie and Drude models) and happened due to quantum and dielectric confinements. Nanocomposites have been synthesized by in-situ thermochemical reduction technique in reducing phosphate glass matrices. The plasmon bands are characterized by the UV–vis spectrophotometer, and shape and size of the nanogold by the transmission electron microscopy. All the nanocomposites are dichroic in nature.     

基于启发搜索空间遗传算法的安全控制最优潮流方法

提出了一种新的可用于安全控制最优潮流问题的遗传算法。该算法应用了一个全新的启发式搜索空间技术,具有更快的收敛速度,缩减了计算的负担。实验采用IEEE 30 bus系统,并以传统的简单遗传算法（SGA）,自适应遗传算法（AGA）,粒子群技术（PSO）,差别演变（DE）作为进行实验比较,结果表明,在具有以及不具有（N-1）断电的偶然性的实例分析中,本文所提算法有更好的鲁棒性,在优化问题上有较好的应用前景。     

Polymer-filler interaction in nanocomposites: New interface area function to investigate swelling behavior and Young's modulus

Polymer-filler interaction for nanocomposites was quantified by introducing Interface Area Function (IAF), to account for the nanofiller characteristics comprising of the specific surface area, correlation length and the filler volume fraction. IAF supplants the immeasurable filler characteristic terms, rendering tractability to the equation derived by considering the restraining forces acting on a nanofiller-elliptical platelet-embedded in polymer matrix. However, neglecting such terms reduces the same to Kraus's equation. Recognition of the due importance of such filler characteristics, by introduction of IAF, resulted in better fitment of swelling data and also conformance with the trend predicted by Zisman's interpretation of surface energy. Experimental values of Young's modulus of natural rubber and styrene-butadiene rubber nanocomposites and those predicted by Guth-Gold and Halpin-Tsai equations for composites conform post-introduction of IAF, with mere 5-20% deviations. The accurate fitment of the resulting constitutive equations indicates suitable integration of the shape and aggregate effects.     

Permeation characteristics and modeling of barrier properties of multifunctional rubber nanocomposites

Nanocomposites used in various applications, like tires, diaphragms etc. must exhibit superior gas permeation behavior along with other properties. Oxygen permeability characteristics of such multifunctional styrene butadiene rubber based nanocomposites, including thermodynamics and kinetic aspects of transport have been discussed here. For the first time, these characteristics have been determined for nano, micro and dual filler based multifunctional nanocomposites. The permeability of the nanocomposites was remarkably decreased by the presence of high loadings of montmorillonite due to high aspect ratio and exquisite dispersion, ascertained from morphological studies. The results were explained by the increment in tortuosity and also correlated with the reduction in free volume. Relative permeabilities were compared to predictions of existing permeation models and a novel function was successfully introduced to address deviations. Finally, the enhanced barrier properties of dual filler based nanocomposites have been explained by the formation of zeta potential driven “nano-blocks” and “nano-channels”.     

Single step modification of micrometer-sized polystyrene particles by electromagnetic polyaniline and sorption of chromium(VI) metal ions from water

This article describes a single-step reproducible approach for the surface modification of micrometer-sized polystyrene (PS) core particles to prepare electromagnetic PS/polyaniline–Fe₃O₄ (PS/PANi–Fe₃O₄) composite particles. The electromagnetic PANi–Fe₃O₄ shell was formed by simultaneous seeded chemical oxidative polymerization of aniline and precipitation of Fe₃O₄ nanoparticles. The weight ratio of PS to aniline was optimized to produce core–shell structure. PS/PANi–Fe₃O₄ composite particles were used as adsorbent for the removal of Cr(VI) via anion-exchange mechanism. The composite particles possessed enough magnetic property for magnetic separation. The adsorption was highly pH dependent. Adsorption efficiency reached 100% at pH 2 in 120 min when 0.05 g of composite particles was mixed with 30 mL 5 mg L⁻¹ Cr(VI) solution. The adsorption isotherm fitted best with Freundlich model and maximum adsorption capacity approached 20.289 mg g⁻¹ at 323 K. The prepared composite was found to be an useful adsorbent for the removal of soluble Cr(VI) ions. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47524.