The interaction of thin polyaniline films with various H‐phosphonates: Spectroscopy and quantum chemical calculations

The conducting form of polyaniline (PANI) is formed by doping of non‐conducting PANI base usually by protonic acids. An alternative way of doping, consisting in an interaction via hydrogen bonding, has been previously proven for H‐phosphonates. In this study, PANI base films are exposed to various H‐phosphonates, changes in the structure of the films are analyzed by ultraviolet–visible, infrared, and Raman spectroscopies and spectroscopic data are compared with quantum chemical calculations. According to our results, the interaction of the PANI base films with H‐phosphonates is realized by hydrogen bonding between the imine nitrogen of PANI and the hydroxy group of the H‐phosphonate tautomeric form, i.e., phosphite. This is in the contrast to the PANI powders doped with H‐phosphonates where both interacting phosphite and non‐interacting H‐phosphonate forms were observed. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46728.     

Bio-mechanochemical synthesis of silver nanoparticles with antibacterial activity

By using a bio-mechanochemical approach combining mechanochemistry (ball milling) and green synthesis for the first time, silver nanoparticles (Ag NPs) with antibacterial activity were successfully synthesized. Concretely, eggshell membrane (ESM) or Origanum vulgare L. plant (ORE) and silver nitrate were used as environmentally friendly reducing agent and Ag precursor, respectively. The whole synthesis took 30?min in the former and 45?min in the latter case. The photon cross-correlation measurements have shown finer character of the product in the case of milling with Origanum. UV–Vis measurements have shown the formation of spherical NPs in both samples. TEM study has revealed that both samples are composites of nanosized silver nanoparticles homogenously dispersed within the organic matrices. It has shown that the size and size distribution of the silver nanoparticles is smaller and more uniform in the case of eggshell membrane matrix implying lower silver mobility within this matrix. The antibacterial activity was higher for the silver nanoparticles synthesized with co-milling with Origanum plant than in the case of milling with eggshell membrane.     

Simplification of separation of the reaction mixture after transesterification of vegetable oil

A heterogeneous reaction mixture is formed by transesterification of vegetable oils. The reaction mixture contains mainly methyl esters of higher fatty acids and glycerol. From this mixture, biodiesel is gained by spontaneous sedimentation in the gravitational field. The sedimentation can be considerably accelerated by controlled addition of water. It was found that addition of small amounts of water to the crude reaction mixture significantly affected the mixture, and substantial changes in the speed of the separation took place. Considerable differences in the composition and quality of the ester and glycerol phases occurred. The optical properties (transmittance and refractive indices) of the heterogeneous reaction mixture are changed after addition of water; this change can be observed spectrophotometrically. This method is applicable to all types of vegetable oils including waste frying oils.     

Multiscale modelling of nanoindentation test in copper crystal

The nanoindentation test in the dislocation free crystal of copper is simulated by a nonlinear elastic finite element analysis coupled with both ab initio calculations of the ideal shear strength and crystallographic considerations. The onset of microplasticity, associated with the pop-in effect identified in experimental nanoindentation tests (creation of first dislocations), is assumed to be related to the moment of achieving the value of the ideal shear strength for the copper crystal. Calculated values of the critical indentation depth lie within the range of experimentally observed pop-ins in the copper crystal. The related indentation load is somewhat lower than that observed in the experiment.     

Terminological (di) Similarities between Information Management and Knowledge Management: a Term Co-Occurrence Analysis

The terminological composition of information management (IM) and knowledge management (KM) is described in order to evidence how much do these areas overlap within the library and information sciences (LIS) space. A term co-occurrence analysis is conducted as from documents extracted from Web of Science, covering the period 1980–2015. To examine the terminological (di) similarity two approaches are applied: ‘overlay visualization? and ‘topic detection?. The percentage of terminological similarity oscillates between 24% and 38% according to the ‘overlay visualization? and ‘topic detection? techniques. At the core of the terminological intersection between IM and KM lies the study around processes, technologies and information systems. However, they are semantically two separate areas that tend to address similar dimensions -such as the managerial, educational and medical, but emphasizing different approach. Moreover, IM refers to the library and information organizations, highlighting the focus on personal information management, human information behavior, health information management, and information resource management. Oppositely, KM highlights the business, management and accounting realms in which topics like knowledge sharing and social networks, knowledge management strategies, and knowledge management projects are prevailing. These results would help to (re) define curricular contents of LIS programs as well as research and practical activities conducted by academicians and managers. This is the most comprehensive quantitative study in examining the epistemic borders between IM and KM in the LIS research. The authors consider that the methodological procedures here employed might be suitable to understand the boundaries between similar fields.

     

Mechanical properties of wood examined by semi-destructive devices

This study presents a comparative evaluation of semi-destructive and destructive testing of wood. Semi-destructive methods are represented by screw-withdrawal test, microdrilling, pin penetration and a new construction of a diagnostic device for in situ evaluation of timber based on the principle of measuring the mechanical resistance to pin being pushed gradually into wood. In order to ascertain the differences between the methods, measuring of three basic softwood species was conducted. One of the aims was to capture the variability of properties brought about by the distribution of properties along the diameter and along the trunk (section) length; therefore, an entire trunk of spruce, fir and pine were used for testing. The accuracy of the prediction of mechanical properties provided by the semi-destructive devices was verified using correlations with mechanical properties established by standard pressure tests in compliance with European norms. The results show a very good correlation of the mean force necessary to push the pin in the timber with wood density and strength in compression along the grain found in standard specimens.     

Self-assembled polyaniline 12-tungstophosphate micro/nanostructures

Polyaniline (PANI) micro/nanostructures were synthesized by the external-template-free oxidative polymerization of aniline in aqueous solution of 12-tungstophosphoric acid (WPA), using ammonium peroxydisulfate (APS) as an oxidant and starting the oxidation of aniline from slightly acidic media (pH 5.4–5.9). The effect of the initial weight ratio of WPA to aniline on molecular structure, morphology, and physicochemical properties of polyaniline 12-tungstophosphate (PANI-WPA) was investigated by FTIR, Raman and inductively coupled plasma optical emission (ICP-OES) spectroscopies, elemental analysis, X-ray powder diffraction (XRPD), scanning and transmission electron microscopies (SEM and TEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and conductivity measurements. The morphological change of polymerization products during a single polymerization process, from non-conducting submicro-/microspherical oligoaniline intermediates to semiconducting PANI-WPA consisted of self-assembled nanotubes and/or nanorods co-existing with submicro-/microspheres, has been revealed by SEM and TEM. The average diameter of nanorods in PANI-WPA samples decreased with increasing the initial WPA/aniline weight ratio. The incorporation of 12-tungstophosphate counter-ions into PANI matrix has been proved by FTIR, Raman and ICP-OES spectroscopies, TGA and DTA analysis. Electrical conductivity of PANI-WPA increased in the range (2.5–5.3) × 10^?3 S cm^?1 with the increase of the initial WPA/aniline weight ratio. The presence of branched structures and phenazine units besides the ordinary paramagnetic and diamagnetic emeraldine salt structural features in PANI-WPA was proved by FTIR and Raman spectroscopies.