A switched chaotic encryption scheme using multi-mode generalized modified transition map

Multimedia Tools and Applications - This paper presents a multi-mode generalized modified transition chaotic map and a switched chaotic encryption scheme based on it. Eight different modes of...     

FPGA realization of a speech encryption system based on a generalized modified chaotic transition map and bit permutation

Multimedia Tools and Applications - This paper proposes a generalized modified chaotic transition map with three independent parameters. A hardware speech encryption scheme utilizing this map along...     

Thermal degradation study of polymethylmethacrylate with AlI3 nanoadditive

Organic polymers in the process of thermal degradation produce a lot of toxic fragments. In this work, we designed a new method of degradation of polymethylmethacrylate (PMMA) materials with aluminum triiodide nanoadditives (AlI₃ NAs). In the present research work, a thermal degradation study of PMMA blends with AlI₃ NAs was carried out by using a specially designed pyrolytic assembly. Different blends of PMMA with AlI₃ (P0, P3, P6, P9, P12, and P15) were prepared by changing the concentration of AlI₃ NAs from 0% to 15%. FTIR and TGA studies show the stability of polymers with AlI₃ NAs. Scanning electron microscopy analysis shows All₃ spread uniformly at nanoscale throughout the polymer matrix. Horizontal burning test (HBT) test confirms that polymer burning is retarded with AlI₃ NAs.     

Correction to: Physico-Chemical Aspects on Uranium and Molybdenum Extraction from Aqueous Solution by Synthesized Phosphinimine Derivative Chelating Agent

Journal of Inorganic and Organometallic Polymers and Materials -     

Improvement in the quality of used sunflower oil by organic and inorganic adsorbents

The objective of the present work was to improve the quality of used sunflower oil. Inorganic (normal and modified silica gel) and organic (normal and modified cellulose powder) adsorbents were used as regeneration agents. Sunflower oil was heated at 180 ± 5 °C, 4 h every day for five consecutive days. The adsorbent materials were individually added to use sunflower oil at 2% level (w/v). Some physico-chemical characteristics were measured to assess the quality of treated-used sunflower oil. The results indicated that all adsorbents under study were effective in improving the overall quality of used sunflower oil. Normal silica gel with small particle size permitted high adsorbing capacity and close to that induced with Magnesol XL which is used commercially in a large scale to improve oil quality. The polarity of the adsorbent substance had a remarkable effect on removing the secondary oxidation products of used sunflower oil. The mode of adsorbents action is discussed.     

Computer simulation of electrical conductivity of graphite-based polypropylene composites based on digital image analysis

The electrical conductivity of polypropylene/graphite (PP/G) composites and polypropylene/graphite/carbon black (PP/G/CB) composites was investigated in this article. A simulation procedure, which is not limited to any specific parameters (i.e. graphite size and shape), was used to numerically compute the electrical conductivity of the composites. The simulations were carried out using a 2D finite element program based on the digital image analysis. The simulation results were in good agreement with the experimental conductivity values even though there were several limitations in using digital image analysis such as sampling, sample preparation, the quality of the image and the choice of the threshold. The microstructures of the surfaces of the composites were observed using scanning electron microscopy (SEM).     

Formation of AlN from Secondary Al Resources

Synthesis of AlN by NH4Cl-assisted direct nitridation of secondary Al resources was studied. Aluminum alloy scrap contained Mg and Zn element was used. Milled Al scrap （-1 mm） was mixed with NH4Cl and heated at 1000℃ for 1 h in presence of 1 L/min N2 flow gas. The nitrided product was evaluated by X-ray diffraction semi-quantitative analysis and scanning electron microscopy （SEM）. Aluminium nitride of 90.5% concentration was obtained with a hexagonal crystalline form. AlN is mostly formed in nano-whisker morphology （50～150 nm） which is homogenously distributed.     

Efficient Mercury Capture Using Functionalized Porous Organic Polymer

The primary challenge in materials design and synthesis is achieving the balance between performance and economy for real‐world application. This issue is addressed by creating a thiol functionalized porous organic polymer (POP) using simple free radical polymerization techniques to prepare a cost‐effective material with a high density of chelating sites designed for mercury capture and therefore environmental remediation. The resulting POP is able to remove aqueous and airborne mercury with uptake capacities of 1216 and 630 mg g^?1, respectively. The material demonstrates rapid kinetics, capable of dropping the mercury concentration from 5 ppm to 1 ppb, lower than the US Environmental Protection Agency's drinking water limit (2 ppb), within 10 min. Furthermore, the material has the added benefits of recyclability, stability in a broad pH range, and selectivity for toxic metals. These results are attributed to the material's physical properties, which include hierarchical porosity, a high density of chelating sites, and the material's robustness, which improve the thiol availability to bind with mercury as determined by X‐ray photoelectron spectroscopy and X‐ray absorption fine structure studies. The work provides promising results for POPs as an economical material for multiple environmental remediation applications.     

Effect of Cu on the magnetic properties and reducibility of Fe2TiO5

Ferrites have been studied for several years due to their wide use as magnetic materials for telecommunications, audio and video, power transformers and many other applications.

Equimolar mixtures of Fe₂O₃ and TiO₂ were fired in a muffle furnace at 1200 °C for 4 h. Mixed samples were prepared by replacing TiO₂ with calculated amounts of CuO (x = 0.2, 0.4, 0.6, 0.8 and 1 mol). The synthesized samples were characterized with X-ray diffraction and their magnetic properties were measured using vibrating-sample magnetometer. The microstructure of the sample was examined using reflected light microscope and scanning electron microscope. The formation of Fe₂TiO₅, Fe₅CuO₈, Cu₂TiO₃ and CuFeO₂ phases were detected whereas their magnetic properties increased with increasing the added mole ratio of Cu²⁺ ions. The isothermal reduction kinetics of synthesized nanocrystallites Ti–Cu mixed ferrite compacts were studied at 500 °C using hydrogen gas. It was found that the reduction rate and the reduction extent increased with increasing the extent of Cu²⁺ (0.2–1) whereas the maximum reduction extent (100%) was detected for pure Cu ferrite (Cu²⁺) while the minimum reduction extent (12%) was detected for pure iron titanate (Cu²⁺ = 0). The magnetic properties showed a drastic improvement upon reduction with hydrogen gas.