This work presents a method to determine the plasticity of clay soils using Fourier transform mid-infrared (FT-MIR) spectroscopy. Samples of mono- and polymineral soils of varying water contents are studied. The FT-MIR results are compared with the results obtained from standard Russian and international methods for the plasticity range. The correlation between the consistency of clay soils, when displaying their plastic properties, and the position of the Si–O stretching band in the FT-MIR spectra is established. The possibility of, and interest in, determining the plasticity characteristics of clay soils using mid-infrared spectroscopy is demonstrated: it yields effectively higher precision results compared to standard test methods. It is shown that the method of IR spectroscopy allows the fixing of the start and the completion of the series of “phase transitions” of the soil in the plastic and liquid state. The significant effect of the concentration of non-clay minerals on the Si–O ν line is that a moisture content curve is noticed, which may help to predict the clay content of the soil without undertaking XRD analysis.

The IR spectrum of a sample from a polymineral natural association of phyllosilicate minerals (clays from the Millerovskoe deposit, Russian Federation) has been analyzed. Calculations are performed...

In this work, a series of comparative studies for the effect of the nine commercially available cationic, amphoteric and nonionic surfactants on the structure and wettability of the montmorillonite based organoclays were performed. The pristine and modified clays were characterized by X-ray diffraction (XRD), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and water contact angle (CA) measurements. It has been observed that the maximum basal spacing and the hydrophobicity of the organoclays increased with the alkyl chain length and chain number of the surfactant. It was found out that this effect is most pronounced when using cationic surfactants. The maximum value of contact angle corresponded to the organoclay obtained using di(hydrogenated tallow) ammonium chloride (DDA). The outcomes of this study are important and relevant to the preparation of effective organoclays for geotechnical, petroleum and polymer nanocomposite applications.

This research evaluates the inhibitory effect of L-amino acids (AAs) with different side chain lengths on Fe (100) surfaces implementing Monte Carlo (MC) simulation. A quantitative and qualitative description of the adsorption behavior of AAs on the iron surface has been carried out. Calculations have shown that the absolute values of the adsorption energy of L-amino acids increase with side chain prolongation; they are also determined by the presence of heteroatoms. The maximum absolute value of the adsorption energy AAs on the iron surface in accordance with the side chain classification increases in the following sequence: Glu (acidic) < Gln (polar) < Trp (nonpolar) < Arg (basic). AAs from nonpolar and basic groups have the best adsorption ability to the iron surface, which indicates their highest inhibitory efficiency according to the results of the MC simulation. The calculation results agree with the experimental data.

The processes in 2–128 nm iron nanoparticles (NP) under 10–800 Ry photon irradiation are studied by detailed Monte Carlo simulations, accounting for the cascade decays of inner-shell vacancies. The cascade decay of vacancies is a crucial factor in the theoretical description of the effect of ionizing radiation on matter. The NPs re-emit most of the energy of an absorbed photon into the surrounding medium with secondary electrons and photons emitted by NP. At incident photon energies under the Fe1s-ionization threshold, most of the energy is carried away by electrons; when photon energy is above the Fe1s-threshold, electrons and photons transfer the energy to the surrounding medium. In the case of large nanoparticles, many low-energy electrons are emitted by NP, over a hundred per one initial photon. Although the energy carried away by them is small, they contribute to forming a high positive charge on the NP, which results in great electric fields near the NP surface. The significance of the NP electric field effect on the DNA repair cycle is discussed.