This study investigates the morphological, mechanical, and viscoelastic properties of bacterial cellulose (BC) hydrogels synthesized by the microbial consortium Medusomyces gisevii. BC gel films were produced under static (S) or bioreactor (BioR) conditions. Additionally, an anisotropic sandwich-like composite BC film was developed and tested, consisting of a rehydrated (S-RDH) BC film synthesized under static conditions, placed between two BioR-derived BC layers. Sample characterization was performed using scanning electron microscopy (SEM), atomic force microscopy (AFM), rheometry, and uniaxial stretching tests. To our knowledge, this is the first study to combine uniaxial and rheological tests for BC gels. AFM and SEM revealed that the organization of BC fibrils ($80\pm 20$ nm in diameter) was similar to that of collagen fibers ($96\pm 31$ nm) found in human dura mater, suggesting potential implications for neurosurgical practice. Stretching tests demonstrated that the drying and rehydration of BC films resulted in a 2- to 8-fold increase in rigidity compared to other samples. This trend was consistent across both small and large deformations, regardless of direction. Mechanically, the composite (BioR+S-RDH) outperformed BC hydrogels synthesized under static and bioreactor conditions by approx. 26%. The composite material (BioR+S-RDH) exhibited greater anisotropy in the stretching tests compared to S-RDH, but less than the BioR-derived hydrogels, which had anisotropy coefficients ranging from $1.29$ to $2.03$. BioR+S-RDH also demonstrated the most consistent viscoelastic behavior, indicating its suitability for withstanding shear stress and potential use in prosthetic applications. These findings should provide opportunities for further research and medical applications.

The study of polymers’ rheological properties is of paramount importance both for the problems of their industrial production as well as for their practical application. Two polymers used for embolization of arteriovenous malformations (AVMs) are studied in this work: Onyx-18^® and Squid-12^®. Viscosity curve tests and computational fluid dynamics (CFD) were used to uncover viscosity law as a function of shear rate as well as behavior of the polymers in catheter or pathological tissue models. The property of thermal activation of viscosity was demonstrated, namely, the law of dependence of viscosity on temperature in the range from 20 ${}^{°}$C to 37 ${}^{°}$C was established. A zone of viscosity nonmonotonicity was identified, and a physical interpretation of the dependence of the embolic polymers’ viscosity on the shear rate was given on the basis of Cisco’s model. The obtained empirical constants will be useful for researchers based on the CFD of AVMs. A description of the process of temperature activation of the embolic polymers’ viscosity is important for understanding the mechanics of the embolization process by practicing surgeons as well as for producing new prospective embolic agents.

This article aims to acquaint as many specialists in the field of heat engineering and thermal power engineering as possible with the possibilities and advantages of metal-mesh catalytic heaters developed at the Institute of Catalysis SB RAS. They are shown to be fundamentally different from catalytic heaters in which ceramic or glass-fiber structures are used as carriers of oxidation catalysts. Practical examples of the implementation of this technology on the example of a hot water boiler, infrared heaters and other small-sized household appliances are given. It was shown experimentally that the supplied gas is oxidized completely, and the efficiency of the laboratory, even unoptimized sample of hot water boiler determined by the inlet and outlet water temperature is not lower than 85 % in the range from 15 to 100 % of nominal capacity and 93 % in the low-power mode. The presented technology enables smooth regulation of the heater output within the whole range from 1.5 to 10 kW with power overlap factor of about 7.

The feasibility of converting local coal-fired boilers into environmentally friendly catalytic boiler plants using fly ashes as easily available complete-oxidation catalysts is demonstrated as a way of solving the environmental pollution problem. The technology of combusting organic fuels in a fluidized bed of heterogenous catalysts is briefly outlined, the principle of catalytic combustion is described, the feasibility of replacing special-purpose catalysts by fly ash is grounded, and the criteria that the fly ash has to meet are experimentally determined. The problems that result from introducing technology of combusting fuels in a fluidized bed of heterogenous catalysts are considered and ways of solving the latter are proposed. The unique compact specialized automated OXI-1 system developed by the authors is presented. The system allows for the catalytic activity of heterogeneous complete-oxidation catalysts to be promptly tested during the methane oxidation reaction by average-skilled personnel (laboratory assistants). Further, the system can be applied to explore the feasibility of using ashes, slurries, and slags containing catalytically active components as cheap and quite efficient complete-oxidation catalysts in fluidized-catalyst-bed boiler plants and combusting organic waste in reactors based on the same principle. According to a developed and tested method, comparative analysis of the catalytic activity of the fly ash from the boiler plant in Yurga, Kemerov oblast, and the commercial special-purpose IK-12-74 deep-oxidation catalysts for hydrocarbons was performed. The activity degree of the fly ash has been experimentally determined at different temperatures and the practicability of using the above fly ash within the range of 750–800°C has been grounded. Further, the minimum residence time of the fuel in the fluidized bed sufficient to maintain the catalytic combustion conditions has been found.