Producing a composite material based on zircon concentrate and nanocrystalline zirconium dioxide

The effects have been examined of adding nanocrystalline zirconium dioxide powder stabilized by yttrium oxide on the production and properties of a composite material based on zircon. It is found that the zirconium dioxide particles at the boundaries of the zircon grains slow the consolidation of the zircon matrix in sintering and zircon grain growth.     

Optimisation of a Swedish district heating system with reduced heat demand due to energy efficiency measures in residential buildings

The development towards more energy efficient buildings, as well as the expansion of district heating (DH) networks, is generally considered to reduce environmental impact. But the combined effect of these two progressions is more controversial. A reduced heat demand (HD) due to higher energy efficiency in buildings might hamper co-production of electricity and DH. In Sweden, co-produced electricity is normally considered to displace electricity from less efficient European condensing power plants. In this study, a potential HD reduction due to energy efficiency measures in the existing building stock in the Swedish city Linköping is calculated. The impact of HD reduction on heat and electricity production in the Linköping DH system is investigated by using the energy system optimisation model MODEST. Energy efficiency measures in buildings reduce seasonal HD variations. Model results show that HD reductions primarily decrease heat-only production. The electricity-to-heat output ratio for the system is increased for HD reductions up to 30%. Local and global CO₂ emissions are reduced. If co-produced electricity replaces electricity from coal-fired condensing power plants, a 20% HD reduction is optimal for decreasing global CO₂ emissions in the analysed DH system.     

Platyphylloside: Metabolism and digestibility reductionin vitro

The metabolism of platyphylloside [(5S)-5-hydroxy-1,7-bis-(4-hydroxyphenyl)-3-heptanone-5-O--d-glucopyranosidel]—known to reduce digestibility—was studiedin vitro in sheep rumen liquor. Platyphylloside is hydrolyzed to 5-hydroxy-3-platyphyllone [(5S)-5-hydroxy-1,7-bis-(4-hydroxyphenyl)-3-heptanone], which is reduced to centrolobol [1,7-bis-(4-hydroxyphenyl)-3-heptanol], via 3-platyphyllone [7-bis-(4-hydroxyphenyl)-3-heptanone]. The digestibility-reducing effect was shown to be correlated with the concentration of centrolobol.     

Polymer composite materials: Technologies and applications

The physicomechanical properties of polymer composites based on aramide fibers that are obtained by the wet-spinning technique with the use of epoxy binders are discussed. The chemical structures of reinforcing fibers and components of epoxy binders; the microstructures, surface structures, and some properties of aramide fibers; and the processes of manufacturing high-strength reinforced composites on their basis are described. Some product samples made of these composites are presented. The investigated reinforcing materials possess high tensile strengths and tensile moduli, which make it possible to obtain products with a high level of operational characteristics on their basis.     

Heat of solidification in refractory metals studied by drop-tube experiments

A number of pure refractory metals have been investigated by drop-tube experiments. The cooling curves have been registered and theoretically analysed. A model for analysing the heat of fusion has been developed. It was found that the heat of fusion was approximately 50% of the tabulated value.     

Erratum to: Digital Twins of CNC Machine Tools in the Reconfiguring of Aircraft Factories

Russian Engineering Research - An Erratum to this paper has been published: https://doi.org/10.3103/S1068798X22100355