Composite systems for medical purposes, created on the basis of hydrophobic silica

Composite systems with certain cytotoxic (AM1/lectin) and adsorption (AM1/gelatin) activity have been developed on the basis of methyl silica and protein molecules – lectin and gelatin. For both types of composites, mechanisms of water binding to the surface and methods of transferring of hydrophobic materials into the aquatic environment have been investigated. The state of interfacial water in air, organic and acid media was studied. It has been found that the presence of a hydrophobic component in composites stabilizes of surface water in a weakly associated state, when a significant part of water molecules does not form hydrogen bonds. Liquid hydrophobic medium enhances this effect, and the strong acid (trifluoroacetic), added to it, promotes the transition of water to a strongly associated state. It has been shown that the redistribution of water in the interparticle intervals of AM1 with protein molecules immobilized on their surface changes under the influence of mechanical loads. Mechanoactivated samples are characterized by the possibility of water penetration into the spaces between the primary particles of methyl silica. It has been shown that immobilization of lectin on the surface of AM1 is accompanied by an increase in the interfacial energy gS from 4.1 to 5.2 J/g. This is due to an increase in the concentration of strongly bound water. If we analyze the changes in the distributions of radii R of the clusters of adsorbed water, we can state that in the water adsorbed by native lectin molecules, there are two main maxima at R = 1 and 3 nm. In the immobilized state, the maximum at R = 1 nm is present in both types of water (of different order), but the second maximum is observed only for more ordered associates.

Thermalization of small quantum systems: From the zeroth law of thermodynamics

Thermalization of isolated quantum systems has been studied intensively in recent years and significant progresses have been achieved. Here, we study thermalization of small quantum systems that interact with large chaotic environments under the consideration of Schrödinger evolution of composite systems, from the perspective of the zeroth law of thermodynamics. Namely, we consider a small quantum system that is brought into contact with a large environmental system; after they have relaxed, they are separated and their temperatures are studied. Our question is under what conditions the small system may have a detectable temperature that is identical with the environmental temperature. This should be a necessary condition for the small quantum system to be thermalized and to have a well-defined temperature. By using a two-level probe quantum system that plays the role of a thermometer, we find that the zeroth law is applicable to quantum chaotic systems, but not to integrable systems.

Comparison of Oxidative Powers of DADP and TATP - A DFT Treatise

Diacetone diperoxide (DADP) and triacetone triperoxide (TATP) are very sensitive organic-peroxide type explosives which are easily synthesized. The present density functional treatment considers oxidative powers of DADP and TATP molecules based on comparison of their interactions with certain group II-metals at the level of B3LYP/6-311++G(d,p). Composite systems of DADP and TATP with Be, Mg and Ca have been considered. Although, in the case of beryllium composites, DADP and TATP and in the magnesium composite of DADP the organic component remains intact, Ca composites of DADP and TATP undergo ring rapture. Certain structural, electronic, quantum chemical and some spectral properties of the composites have been obtained and discussed.

The effect of temperature, humidity and mechanical properties on crack formation on external thin plasters of ETICS

External Thermal Insulation Composite Systems (ETICS) are widely used in the northern hemisphere in retrofitted and new external walls. The outer layer of ETICS is usually a thin layer of plaster. The effects of temperature and humidity on the hygrothermal behaviour and mechanical properties of thin plasters have been quantified by conducting several experiments to determine the possibility of crack formation. Combinations of plasters using four types of binders are tested: mineral, polymer, silicate and silicone. Plasters are tested as four systems consisting of a base coat, a glass-fibre reinforcement mesh and a finishing coat. Sorption curves of the plaster systems are determined to gather data for numerical simulations. The coefficients of thermal and hygroscopic expansion are determined. The modulus of elasticity and tensile strength of four different plasters are measured to allow the calculation of crack formation in ETICS and suggest the distances between the deformation joints. The method demonstrated in this paper makes it possible to calculate the crack formation caused by the temperature and moisture shrinkage in the thin exterior plaster of ETICS.

Study of new elastomeric composite systems containing wood ash based alternative filler

The presented paper deals with the preparation of the new types of elastomeric composite systems containing an alternative filler based on wood ash or fly ash. Wood ash (fly ash) is generated as the waste from the process of wood pellets burning in the pellet boilers. The results of the EDX analysis confirmed that CaO and SiO2 are the most represented components of wood ash, which contains commonly used white fillers, such as kaolin or silica. Therefore, wood ash was used as an alternative ecological filler in a function of a partial replacement for the commonly used carbon black filler in the elastomer systems. Rheological properties and cure characteristics of prepared elastomer composite systems and tensile properties of resulting vulcanizates have been studied. The prepared elastomeric systems were also subjected to a Payne effect study. The obtained results showed the degree of filler - filler interactions as well as the degree of mutual interactions between alternative filler particles and elastomeric matrix.