Comparative Study of Catalytic Activity of Recyclable Au/Fe3O4 Microparticles for Reduction Of 2,4-Dinitrophenol and Anionic, Cationic Azo Dyes.

We synthesized Au/Fe3O4 microparticles. Initially, citrate-capped Fe3O4 micro-sized particles were synthesized by the co-precipitation method with an excess amount of trisodium citrate. Gold ions were reduced on the surface of citrate-capped Fe3O4 and grew as gold sub-microparticles with an average diameter of 210 nm on the surface. The characteristic SPR peak of gold nanoparticles on the surface of Fe3O4 was detected at 584 nm, whereas the absorption in the near-infrared region was increased. SEM images has proved that the synthesized Au/Fe3O4 composite microparticles has an average diameter of 1.7 micrometers. The results of XRD patterns proved the existence of both crystal phases of Fe3O4 and Au particles. To investigate the catalytic activity, the reaction rate constant of reduction of 2,4-dinitrophenol (2,4-DNP) and degradation of Congo red (CR), and methylene blue (MB) with NaBH4 in the presence of Au/Fe3O4 catalyst was monitored by UV-Vis spectroscopy. The initial reaction rate constant calculated from the change in characteristic peak absorptions of 2,4-dinitrophenol was 3.97×10-3 s-1, while the reaction rate constants for the degradation of CR and MB were 9.72×10-3 s-1 and 14.25×10-3 s-1 respectively. After 5 cycles, Au/Fe3O4 microparticles preserved 99 % of the reaction rate constant, exhibiting considerable recycling efficiency in the reduction of nitro groups.

Fabrication of Wet-Spun Wool Keratin/Poly(vinyl alcohol) Hybrid Fibers: Effects of Keratin Concentration and Flow Rate.

Sheep wool is one of the most common wastes derived from agriculture and also a great source of keratin. In this study, chemical reduction and alkali hydrolysis methods of extracting keratin from wool were studied for the purpose of reusing the waste wool, and the products were used to fabricate wet-spun hybrid fibers by mixing with PVA. The comparative yield of the two extraction methods was investigated, and the optimal precursor concentration ratio for keratin extraction was identified. The effects of keratin concentration and wet-spinning flow rate on the mechanical properties of fabricated fibers were studied. Therefore, this study encourages the further investigation of wool keratin-based hybrid biomaterials, which could provide a new way to reuse waste wool.

Activation cross sections of proton-induced reactions on natural platinum up to 30 MeV.

Activation cross sections of proton-induced reactions on natural platinum were measured. The stacked-foil activation technique and high-resolution gamma-ray spectrometry were used. The production cross sections of 198, 196, 196m2, 195, 194, 193, 192, 191Au, 191Pt, and 192, 190Ir were determined up to 30 MeV. The experimental results were compared with previous experimental data and theoretical calculations in the TENDL-2019 library.

Production cross sections of 52Mn in alpha-particle-induced reactions on natural vanadium.

Activation cross sections of alpha-particle-induced reactions on natural vanadium were measured. The production cross sections of 54, 52gMn, 51Cr, 48V, and 47, 46gSc were determined up to 50 MeV. The stacked-foil activation technique and high-resolution gamma-ray spectrometry were used. The experimental results were compared with previous experimental data and theoretical calculations in the TENDL-2019 library. The physical yield of the medical radionuclide 52gMn was derived from the measured cross sections.

Production cross sections of 45Ti in the deuteron-induced reaction on 45Sc up to 24 MeV.

Activation cross sections of the medically interesting radionuclide 45Ti were investigated in the deuteron-induced reaction on 45Sc. 45Ti can be produced in a radioactive-contamination-free form in the 45Sc(d,2n)45Ti reaction below 15 MeV deuteron energy. The stacked foil activation technique and γ-ray spectrometry were used to determine the cross sections. The physical yield of 45Ti was deduced from the measured cross sections.

Production cross sections of 68Ga and radioactive by-products in deuteron-induced reactions on natural zinc.

Activation cross sections of the deuteron-induced reactions on natural zinc are studied for the production of the medical radionuclide 68Ga. The stacked foil activation method and the γ-ray spectrometry were used. Co-produced radionuclides 65,66,67Ga, 63,65,69mZn, 61Cu, and 58Co are also investigated to evaluate amounts of impurities for practical use of 68Ga. Physical yields of the radionuclides were deduced from the measured cross sections.

Investigation of the structure and interaction of cellulose triacetate I crystal using ab initio calculations.

The crystal structure of cellulose triacetate I (CTA I) was investigated using first-principles density functional theory (DFT) calculations. The results are in good agreement with the experimental structure obtained by Sikorski et al. when performing the calculation with inclusion of the dispersion correction. However, the cell parameters calculated with inclusion of the dispersion correction are slightly smaller than those experimentally obtained, especially along the a-axis. This smaller cell parameter could be reasonably explained by considering thermal expansion effects, since optimization with the density functional calculation gives the structure without inclusion of thermal effects. The atoms-in-molecules (AIM) theory is also employed to identify and characterize interatomic interactions in the CTA I crystal. CH/O interactions sites are shown to exist in the crystal structure of CTA I. Moreover, CH/O interactions are considered the main interactions in operation to maintain the crystal structure of CTA I.