Effect of Flax By-Products on the Mechanical and Cracking Behaviors of Expansive Soil.

Expansive soils, prone to significant volume changes with moisture fluctuations, challenge engineering infrastructure due to their swelling and shrinking. Traditional stabilization methods, including mechanical and chemical treatments, often have high material and environmental costs. This study explores fibrous by-products of flax processing, a sustainable alternative, for reinforcing expansive clay soil.

Modeling of Catalytic Centers Formation Processes during Annealing of Multilayer Nanosized Metal Films for Carbon Nanotubes Growth.

The paper presents a theoretical model of the catalytic centers formation processes during annealing of multilayer nanosized metal films for carbon nanotubes growth. The approach to the description of the model is based on the mass transfer processes under the influence of mechanical thermoelastic stresses, which arise due to the difference in the thermal expansion coefficients of the substrate materials and nanosized metal layers. The thermal stress gradient resulting from annealing creates a drop in the chemical potential over the thickness of the film structure.

Anomalous hardening behavior of a calcium phosphate bone cement.

In this work, an anomalous microscopic and macroscopic behavior during the hardening process of a calcium phosphate cement, based on anhydrous dicalcium phosphate, was observed. Indeed, the standard compressive strength measurements provided completely unexpected results, which encouraged a deeper investigation by means of X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron and atomic force microscopies. The energy dispersive X-ray diffraction mode was preferred to the conventional angular dispersive one, the former being particularly suitable for the real-time studies, allowing us to follow the hardening process in situ and to confirm that the investigated cement undergoes a long-time crystallization much more complex than expected.

Cyclization of 2-acyl- and 2-thioacylaminobenzylcyclopropanes in the gas phase and solution.

Mass spectrometry proved itself to be a powerful tool to predict the directions and yields of mono- molecular reactions of organic compounds. Electron ionization (EI) and electrospray ionization (ESI) were used to study possible transformations of N-(ortho-cyclopropylmethylphenyl)arylamides I and N-(ortho- cyclopropylmethylphenyl)arylthioamides II as well as their para-isomers III and IV in a mass spectrometer and to predict directions and yields of their acid catalyzed cyclization reactions. Several five-eight-membered heterocycles were proposed as possible products of intramolecular transformations of compounds I and II.

Cyclization of the substituted N-(ortho-cyclopropylphenyl)-N'-aryl ureas and thioureas in the gas phase and solution.

Electron ionization (EI), chemical ionization (CI), tandem mass spectrometry, high-resolution measurements, and labeling studies as well as quantum chemical calculations were used to understand the behavior of the molecular radical cations (EI) and protonated molecules (CI) of substituted N-(ortho-cyclopropylphenyl)-N'-aryl ureas and N-(ortho-cyclopropylphenyl)-N'-aryl thioureas in a mass spectrometer. Fragmentation schemes and possible mechanisms of primary isomerization were proposed. According to the fragmentation pattern, formation of the corresponding benzoxazines and benzothiazines was considered as the major process of isomerization of the original M(+.