Dielectric and spectroscopic analysis of cobalt doped potassium hexatitanate (K2Ti6O13) ceramics

Pure and cobalt doped (x = 0.05, 0.10, 0.15 mol %) polycrystalline potassium hexatitanate (K₂Ti₆O₁₃) ceramics were synthesized using conventional solid state reaction route. XRD result confirmed the successful doping of Co in the K₂Ti₆O₁₃ matrix, as no additional peak was observed in the pattern. Dielectric permittivity was found to decrease with the increase in frequency while it increased with the increase in doping. The dielectric loss decreased with small doping whereas excessive doping caused its augmentation. Ac conductivity (σ _ac ) has also been studied as a function of frequency at room temperature for all the samples. Scanning Electron Microscope (SEM) inspection of the synthesized samples showed the formation of rod like shapes. FTIR analysis was carried out to identify the chemical bonds present in the system.     

Role of big data management in enhancing big data decision-making capability and quality among Chinese firms: A dynamic capabilities view

This study examines the antecedents and influence of big data decision-making capabilities on decision-making quality among Chinese firms. We propose that such capabilities are influenced by big data management challenges such as leadership, talent management, technology, and organisational culture. By using primary data from 108 Chinese firms and utilising partial least squares, we tested the antecedents of big data decision-making capability and its impact on decision-making quality. Findings suggest that big data management challenges are the key antecedents of big data decision-making capability. Furthermore, the latter is vital for big data decision-making quality.     

A study of phase separated Ni66Nb17Y17 metallic glass using atom probe tomography

Microstructural characterization of Ni₆₆Nb₁₇Y₁₇ as spun metallic glass ribbon was carried out using atom probe tomography. A comparison of different experimental conditions for pulsed laser and pulsed voltage field evaporation reveal that the laser pulsing can be optimized to avoid preferential evaporation of yttrium. Atom probe tomography measurements illustrate that the sample undergoes phase separation resulting in two interconnected phases during the process of vitrification. The yttrium-enriched phase was depleted in niobium and yttrium-depleted phase was enriched in niobium. Moreover, detailed analyses of the roller-contact and non-contact sides of the melt-spun ribbon show different wavelength of phase separated regions revealing that the degree of phase separation is directly associated with the cooling rate.     

Electrospun nanofibers from ferrocene-containing multiblock copolymers prepared via RAFT polymerization with F127 modified precursor

Electrospun nanofibers from copolymers composed of ferrocene side chains and PEO₁₀₀-PPO₆₅-PEO₁₀₀ (F127) were fabricated in chloroform and N,N–dimethyl formamide solutions (V/V = 95:5) at room temperature. Ferrocene-containing multiblock copolymers (PFcMA_n-F127-PFcMA_n) were synthesized through reversible addition-fragmentation chain transfer polymerization using s-1-dodecyl-s''- (α, α'-dimethyl-α''-acetic acid) trithiocarbonate (DDMAT) modified F127 with 2- (methacryloyloxy) ethyl ferrocencarboxylate (FcMA). The structures of as-obtained chemicals were characterized by FTIR, ¹H NMR, and ¹³C NMR. Additionally, the block copolymers molecular weight and polydispersity were measured using gel permeation chromatography. The electrochemical responsiveness of the polymers was investigated using cyclic voltammetry as well as the thermal stabilities of polymers and precursors were tested through DSC and TGA. The morphologies of electrospun fibers were observed through field emission scanning electronic spectroscopy and a fibrous diameter of 300–1100 nm was obtained. The results indicated that the suitable molecular weight of ferrocene -containing polymer would be processed in nanofibrous.     

Photocatalytic degradation of nitrotoluene in aqueous TiO2 suspension.

TiO2-mediated photocatalytic degradation process was employed to treat aqueous 2-, 3- and 4-NT (nitrotoluene) pollutants. The NT disappearance and TOC removal rates for three isomers showed no significant differences. Three hydroxylated aromatic intermediates resulting from the photocatalytic degradation of 4-NT were identified; this suggested two (initial) degradation pathways. Formation of acetic acid, formic acid, and formaldehyde was also noted. The mineralization products included NH4+, NO3- and CO2. N2 bubbling or the presence of a positive hole acceptor during 4-NT degradation resulted in a high 4-aminotoluene formation. This indicated an effective reduction of 4-NT's nitro group to amino moiety. Generally, Pt-loaded TiO2 (Pt-TiO2) had no influence on the disappearance rate of 4-NT. However, the use of Pt-TiO2 along with a higher light intensity source resulted in an accelerated TOC removal.     

Studying nearest neighbor correlations by atom probe tomography (APT) in metallic glasses as exemplified for Fe40Ni40B20 glassy ribbons

A next nearest neighbor evaluation procedure of atom probe tomography data provides distributions of the distances between atoms. The width of these distributions for metallic glasses studied so far is a few Angstrom reflecting the spatial resolution of the analytical technique. However, fitting Gaussian distributions to the distribution of atomic distances yields average distances with statistical uncertainties of 2 to 3 hundredth of an Angstrom. Fe₄₀Ni₄₀B₂₀ metallic glass ribbons are characterized this way in the as quenched state and for a state heat treated at 350 °C for 1 h revealing a change in the structure on the sub-nanometer scale. By applying the statistical tool of the χ² test a slight deviation from a random distribution of B-atoms in the as quenched sample is perceived, whereas a pronounced elemental inhomogeneity of boron is detected for the annealed state. In addition, the distance distribution of the first fifteen atomic neighbors is determined by using this algorithm for both annealed and as quenched states. The next neighbor evaluation algorithm evinces a steric periodicity of the atoms when the next neighbor distances are normalized by the first next neighbor distance. A comparison of the nearest neighbor atomic distribution for as quenched and annealed state shows accumulation of Ni and B. Moreover, it also reveals the tendency of Fe and B to move slightly away from each other, an incipient step to Ni rich boride formation.     

Solubility of chemical warfare agent simulants in supercritical carbon dioxide: experiments and modeling

Solubility data are reported for ethyl phenyl sulfide (EPS) and 2-chloroethyl ethyl sulfide (CEES) in CO₂ at temperatures from 25 to 100 °C. These two sulfide-based compounds are homomorphs for chemical warfare agents (CWAs). Both sulfide–CO₂ mixtures exhibit type-I phase behavior. The maximum in the 100 °C isotherm is approximately 2600 psia for the CEES–CO₂ system and approximately 3400 psia for the EPS–CO₂ system. The Peng–Robinson equation of state (PREOS) is used to model both sulfide–CO₂ mixtures as well as the phase behavior of the 2-chloroethyl methyl sulfide (CEMS)–CO₂ system previously reported in the literature. The Joback–Lydersen group contribution method is used to estimate the critical temperature, critical pressure, and acentric factor for the sulfides. Semi-quantitative estimates of the phase behavior are obtained for the CEES–CO₂ and EPS–CO₂ systems with a constant value of k_ij, the binary interaction parameter, fit to the 75 °C isotherms. However, very poor fits are obtained for the 2-chloroethyl methyl sulfide–CO₂ system regardless of the value of k_ij. On the basis of the high solubility of EPS and CEES in CO₂, supercritical fluid (SCF)-based technology could be used to recycle or recover chemical warfare materials.     

Biofabrication of broad range antibacterial and antibiofilm silver nanoparticles

Silver nanoparticles (AgNPs) were biosynthesized via a green route using ten different plants extracts (GNP1‐ Caryota urens, GNP2‐Pongamia glabra, GNP3‐ Hamelia patens, GNP4‐Thevetia peruviana, GNP5‐Calendula officinalis, GNP6‐Tectona grandis, GNP7‐Ficus petiolaris, GNP8‐ Ficus busking, GNP9‐ Juniper communis, GNP10‐Bauhinia purpurea). AgNPs were tested against drug resistant microbes and their biofilms. These nanoparticles (NPs) were characterised using UV‐vis spectroscopy, transmission electron microscope, Fourier transform infrared spectroscopy, X‐ray diffraction and Image J software. Most of the AgNPs were distributed over a range of 1 of 60 nm size. The results indicated that AgNPs were antibacterial in nature without differentiating between resistant or susceptible strains. Moreover, the effect was more prominent on Gram negative bacteria then Gram positive bacteria and fungus. AgNPs inhibited various classes of microbes with different concentration. It was also evident from the results that the origin or nature of extract did not affect the activity of the NPs. Protein and carbohydrate leakage assays confirmed that the cells lysis is one of the main mechanisms for the killing of microbes by green AgNPs. This study suggests that the action of AgNPs on microbial cells resulted into cell lysis and DNA damage. Excellent microbial biofilm inhibition was also seen by these green AgNPs. AgNPs have proved their candidature as a potential antibacterial and antibiofilm agent against MDR microbes.Inspec keywords: silver, nanoparticles, antibacterial activity, nanofabrication, microorganisms, ultraviolet spectra, visible spectra, transmission electron microscopy, Fourier transform infrared spectra, X‐ray diffraction, proteins, DNA, nanomedicine, biomedical materials, cellular biophysicsOther keywords: biofabrication, broad range antibacterial nanoparticles, antibiofilm silver nanoparticles, plant extract contribution, drug resistant microbes, UV‐vis spectroscopy, transmission electron microscope, Fourier transform infrared spectroscopy, X‐ray diffraction, Image J software, resistant strains, susceptible strains, Gram positive bacteria, fungus, protein leakage assays, carbohydrate leakage assays, cell lysis, DNA damage, Ag     

Computation of environmental forces for use in offshore vessel dynamic analysis

Equations for the computation of environmental loadings due to wind and ocean current on an offshore vessel are presented. A systematic procedure for generating a wave force time history from a given random sea spectrum for use in offshore vessel dynamic analysis is also discussed and is illustrated with a practical example.