Antibacterial polymer composites based on low‐density polyethylene and essential oils immobilized on various solid carriers

In this study, we investigated the antibacterial modification of polymers with biologically active substances in essential oils [EOs; linalool, 4‐allylanisole (ALY), and trans‐anethole]. These compounds were thermoplastically incorporated into a low‐density polyethylene matrix via solid inert carriers [wood flour (WF) and talc and molecular sieves] with physically immobilized EOs. The concentrations of the antibacterial modifiers on the carriers and in the resulting composites were determined with three chromatographic techniques (gas chromatography with mass spectrometry, pyrolysis and gas chromatography with mass spectrometry, and high‐performance liquid chromatography). The effects of such modifications to the mechanical properties of the prepared composites were studied by stress–strain analysis. Interactions on the polymer matrix carriers were observed by scanning electron microscopy. The prepared composites were also tested for antibacterial activity against both Gram‐negative and Gram‐positive bacterial strains. The highest efficiency of isothermal immobilization was found for systems consisting of ALY and WF. This finding was in accordance with microbiological studies. The phase of immobilizing the EOs did not influence the mechanical properties of the studied composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42816.     

Liquid–Liquid Test Reactions to Characterize Two-Phase Mixing in Microchannels

Multiphase flow is often found in chemical engineering, food processing, or analytical devices. First contacting and droplet generation as well as coalescence and redispersion are important for the flow characteristics. In all processes, the channel geometry, fluid properties, and flow velocity determine the flow regime, droplet size, and interfacial area. The hydrolysis of alkyl acetates in organic phase with sodium hydroxide NaOH in the aqueous phase is investigated as flexible test reaction for mass transfer and interfacial area determination. The alkyl group is chosen from ethyl, isopropyl, or n-butyl, which differ in water solubility, diffusivity, and rate constant, for adequate design of the characteristic time for mass transfer. The consumption of NaOH is used for calculation of specific area and related mass transfer coefficient. Different channel geometries are characterized and design considerations are derived.     

Designing Zr-Cu-Co-Al Bulk Metallic Glasses with Phase Separation Mediated Plasticity

New Zr-based bulk metallic glasses (BMGs) with improved plasticity were developed in the Zr-Cu-Co-Al system by a combination of Zr₄₅Cu₅₀Al₅ and Zr₅₅Co₂₅Al₂₀ BMGs with a certain concentration ratio. The compressive plasticity of the investigated alloys depends strongly on the concentration ratio of the two BMGs. Because of the positive enthalpy of mixing between Cu and Co (??H_Cu-Co?=?+9?kJ/mol), a strong repulsive interaction between Cu and Co is introduced, whereas an attractive interaction exists among the other constituent elements in the liquid state. When two BMGs are combined at a 1:1 concentration ratio, a maximum compressive plasticity of ~12?pct is achieved for the Zr₅₀Cu₂₅Co_12.5Al_12.5 BMG. The plasticity enhancement is attributed to atomic-scale chemical/structural fluctuations achieved through liquid-phase separation.     

Analysis of Giouan Battista Bellaso’s cipher challenges of 1555

In his book, Noui et singolari modi di cifrare, Giouan Battista Bellaso presented to his readers three challenge ciphertexts. Two of them are based on a polyalphabetic cipher with a mixed primary reciprocal alphabet and a long key, whereas the third one uses four independent homophonic substitution alphabets that change after each word. A successful approach to solving these ciphers, to which Bellaso gave the name “terzo modo” and “quarto modo,” performs a simulated annealing attack directly on the primary alphabet, respectively the four homophonic alphabets at once. This article focuses on the various applied fitness functions. The solutions for the ciphertexts are given and finally discussed, with a view toward the possibility of a hidden message within the plaintexts.     

AlNiYCo Amorphous Matrix Composites Induced by Bismuth and Lead Additions

(Al₈₅Ni₅Y₈Co₂)₉₈Bi₂ and (Al₈₅Ni₅Y₈Co₂)₉₈(Bi₅₀Pb₅₀)₂ alloys are rapidly solidified using the single-roller melt-spinning method. Al₈₅Ni₅Y₈Co₂ amorphous matrix composites containing faceted BiY particles are synthesized by the liquid-solid reaction between added bismuth and constituents of the molten Al-Ni-Y-Co glass-forming alloy. The microstructure of the rapidly quenched (Al₈₅Ni₅Y₈Co₂)₉₈(Bi₅₀Pb₅₀)₂ multiphase composites consists of Al-based amorphous matrix and crystalline Pb-rich and BiY particles. The Pb-rich particles stem from liquid-liquid and monotectic reactions induced by lead addition. The phase constitution and microstructure are investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The reaction-induced crystalline BiY and Pb-rich particles are uniformly distributed in the amorphous matrix. The microstructure formation of the rapidly quenched alloys was discussed.