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The transformation of traditional business models of public catering enterprises into their innovative version occurs under the influence of a certain set of external factors. The assessment, both negative and positive, of the influence of external factors should be carried out according to adapted methods suitable for the situation and the chosen industry. At the moment, a set of external factors that have a significant impact on the formation of successful business models remains insufficiently studied. The need for research is also due to the lack of a system of factors that must be taken into account when forming an adaptive business model for public catering enterprises. The purpose of the study is to form a system of factors that have a significant impact on the public catering sector, and to assess the nature of the influence of each factor on the activities of public catering enterprises. The research methods are: comparative analysis, statistical analysis, benchmarking, classification and ranking, Churchman - Akoff method, PEST-analysis. The result of the study is a developed system of factors that have a significant impact on the catering industry, and an assessment of the nature of the influence of each factor, as well as identified industry risks and identified strategies for responding to them. The authors conclude that the most significant factors influencing the formation of a successful business model in the field of public catering are: the sanctions imposed against Russia by some countries; increased investment in catering projects; increasing the importance of higher education; technological improvements, the introduction of modern technologies in the catering infrastructure.

The article examines theoretical approaches to defining the concept of “self-employment” as a special type of employment with its own forms of manifestation, as entrepreneurship, as a form of economic activity of an individual, as a special structure in a multi-structure economy, as a socio-economic phenomenon, as a phenomenon that can lead to the integration of the interests of society and people and others. It has been suggested that only a comprehensive consideration of the characteristics of self-employment, its genetic basis, qualities, properties and forms of manifestation will allow us to provide a substantiated author’s understanding of self-employment.

The intensification of the sphere of the study of critical thinking based on formal logical principles, found in the works of modern researchers, actualizes the appeal to the topic of logical analysis of language. The program settings of the course «Logic and critical Thinking» are focused on the thorough immersion of participants in the acute issues of the use of natural language. The purpose of this article is to reflect on the subjects of ambiguity in language and the operational tasks of pedagogical practice in critical thinking that arise in this regard. Understanding the experience of implementing an educational project is aimed at outlining the logical foundations of critical skills built through the prism of students’ reflexive vision. The framework of language and thinking problems is evaluated through ranking of course positions illustrating the possibilities of developing critical thinking through comprehension of language forms. The registered ambiguity is shown taking into account the requirements of the verbal or situational context in the application of the concept. The analysis of texts carried out in a practical lesson leads to the understanding of ambiguity as a linguistic norm that requires acceptance and appropriate cognitive support. The achievement of students becomes a competent vision of the content of the problem of ambiguity, characterizing critical judgment abilities in handling information. Attention is focused on the fact of terminological ambiguity, which implies the identification of clear meanings and deepening into the processes of cognition as such. The conclusion is made about the need for methodical development of the problem of ambiguity in language, since the focus on the subtleties of intellectual and speech mechanisms contributes to the formation of critical skills of project participants.

Gas chromatography with mass spectrometric detection (GC-MS) was used to study the composition of bromides obtained upon selective cleavage (chemolysis) of the C-O bond of ether/ester bridges under the action of BBr₃ in oil components from ten oil and natural bitumen samples. It is shown that most of the samples under study demonstrate the absence of mono- and dibromides of alkanes, alkylcyclohexanes, pregnanes and steranes, cheilanthanes and hopanes in the products of chemolysis. Monobromides of n-alkanes have been identified only in the products of chemolysis of oil components isolated from maltha of the Ashalchinskoye oilfield and the products of its biodegradation under laboratory conditions. In total, the identified products of selective cleavage of ether/ester bridges include mono- and dibromides of alkylbenzenes: mainly (С₁₃-С₂₂)-alkyltrimethylbenzenes, (С₁-С₇)-naphthalenes, phenanthrene, dibenzothiophene and their homologues. Monobromides of C₆-biphenyl, C₄-tetralin, dibromides of (C₂-C₆)-benzothiophenes, (C₂-C₅)-biphenyls, C₁-tetralin, fluorene, and C₂-fluorene have been also identified. Tribromides of (С₂-С₄)-naphthalenes, С₂-phenanthrene, and (С₁-С₂)-fluorenes have been identified in a limited number of samples. In chemolysis products, dibromides occur more rarely than monobromides, while tribromides are much less common than dibromides. The results obtained indicate that the above-mentioned compounds are partially present in oils as structural fragments connected with other fragments of the oil components through one or much less often through two or three ether/ester bridges. The list of structural fragments linked via ether/ester bridges, their composition and relative content differ in oil components of different oil and natural bitumen samples. Ethyl esters of aliphatic acids from C₁₂ to C₃₂, with a clear predominance of even acids and a maximum corresponding to C₁₆ and C₁₈, have been identified in the products of chemolysis of almost all samples.

The physicochemical properties and catalytic activity of regenerated spent aluminium-cobalt-molybdenum hydrotreatment catalyst have been investigated under cracking conditions in the model systems n-dodecane - toluene and decalin - toluene - n-hexane. A series of experiments to study the catalytic activity of the sample was carried out using a flow-type laboratory installation within the temperature range 430-470 °C, nitrogen pressure 1.6 MPa, liquid hourly space velocity 0.5-3.0 h^-1. The directions of transformation were determined for paraffin and naphthenic hydrocarbons by means of gas chromatography - mass spectrometry. Paraffin hydrocarbons enter into cracking, isomerisation and compaction reactions. Naphthenic hydrocarbons are transformed into the products of isomerisation, dehydrogenation and compaction. Predominant dehydrogenation of decalin with the formation of naphthalene and hydrogen is observed in the system under investigation. A positive role of hydrogen in thermodestructive processing of heavy oil residues is observed due to the hydrogenation of nonlinear olefin hydrocarbons and aromatic hydrocarbon intermediates, which decreases the rate of coke formation. The corresponding reaction rate constants were calculated, and the results were analysed. Conclusions are drawn about the prospects of introducing a regenerated spent hydrotreatment catalyst into the procedure of thermodestructive processing of heavy oil residues.

The chemical composition and reactivity of the native cellulose of cotton grass ( Eriophorum scheuchzeri ) in the production of cellulose nitroesters based on this type of raw material are investigated to assess the suitability of the native cellulose fibres of the seed pods ( Eriophorum scheuchzeri ) for the production of cellulose nitroesters on this basis. It is shown that the mass fraction of cellulose in the studied plant raw materials reaches 79 %. The degree of cellulose polymerization is 1510 units. The possibility of obtaining cellulose nitroesters in a practical yield of 64 % on the basis of this type of plant raw materials without preliminary delignifying treatment has been revealed. The chemical composition of the obtained cellulose nitroesters has been established. Their technical compliance with colloxylin H is shown. Based on the conducted studies, an intermediate conclusion is made about the potential suitability of this type of plant raw materials for the production of cellulose nitroesters.

The phase compositions and particle morphology of nanostructured Co-Pt system, obtained by the reduction of aqueous solutions of precursors with hydrazine hydrate, have been studied (for the first time in the Pt-rich region) by X-ray diffraction analysis (XRD), transmission electron microscopy (coupled with electron diffraction (ED)), thermogravimetry, small-angle X-ray scattering analysis (SAXS) and elemental analysis of the samples. As determined by XRD, with Co content less than approximately 60 at%, the only phase is determined: the face-centred cubic ( fcc ) phase of the solid solution of Co in Pt, with the upper limit of Co solubility in Pt equal to 18±1 at%. For Co content in the solid solution higher than its solubility limit during the synthesis, diffraction-undetectable phase (phases) is also formed in addition to the fcc solid solution phase. The presence of such phases was confirmed by the results of SAXS, and their metal nature, rather than oxide-hydroxide one, was confirmed by XRD, ED, and thermal analysis.

The catalytic reaction of n-heptane (n-C₇H₁₆) oxidation with molecular oxygen has been studied. Various compositions of the polymer catalyst Mn-P4VP/MBAA (where Mn-P4VP is manganese-immobilised poly-4-vinylpyridine and MBAA is N,N′-methylene-bis-acrylamide) containing 2-5 wt% Mn were prepared and tested. The concentration of manganese in the catalyst based on immobilized metal-polymer complexes is within the range of 2-5 wt% Mn. The oxidation reaction was carried out at a ratio of components n-C₇H₁₆/O₂/polymer catalyst with Mn = 1 : 3.38 : 0.003 and time 6 h within the temperature range 303-383 K. The data on the yield of the major products of n-heptane oxidation are presented, taking into account the initial components, catalyst composition, temperature and the time of oxygen contact with the reacting components. It has been established that during the oxidation of _n-C₇H₁₆ (303-383 K), the yield of alcohols is higher than the yield of other oxidation products. The oxidative conversion of _n-heptane increases from 45 to 75 mol% with an increase in temperature in the range of 303-383 K. For the multistage oxidation of n-heptane with oxygen, a kinetic model was selected and considered. On the basis of this model, the reaction rate constants were calculated in the range of 303-383 K considering the degree of heptane conversion. The activation energy of n-heptane oxidation was estimated, taking into account the method of choosing the most plausible parameter and experimental data on n-heptane convection.

One of the main problems in oil production is the formation of stable oil-water emulsions that cause corrosion of pipelines, malfunction of pumping equipment, and poisoning of catalysts at refineries. The features of the viscosity-temperature behaviour of high-viscosity resinous crude oil from the Russkoye field (Yamal-Nenets autonomous district) and its 30 wt% emulsion after exposure to electromagnetic and low-frequency acoustic fields are investigated. Electromagnetic treatment of crude oil leads to a decrease in the phase transition temperature and the yield strength coefficient. Low-frequency acoustic processing of the emulsion is accompanied by a decrease in the effective viscosity and the yield strength coefficient. After a complex wave action, the viscosity-temperature characteristics of crude oil continue to fall, and the stability of the formed emulsions decreases due to the intense coalescence of water-phase droplets. It is shown that the amount of released asphaltenes in oil-containing systems decreases after wave treatment. On the contrary, after a complex impact, their content in crude oil increases, while in the emulsion it continues to decrease. This is likely to occur due to the release of hydrocarbons occluded in the asphaltene structure into the liquid oil phase.

Chemical modification of phenyl-formaldehyde oligomers (PFO) was carried out, and compositions based on elastomer, co-oligomer and bitumen were developed in order to achieve significant improvement of characteristics and expand the areas of PFO application. The phenol-formaldehyde oligomer was modified with carbamide by co-polycondensation in an alkaline medium. The basic physicochemical, physical-mechanical and performance characteristics of the co-oligomer were studied. The co-oligomer of the new composition, obtained at the first stage of the investigation, was used as a binder. At the second stage of investigation, a three-component composition was developed on the basis of elastomer, co-oligomer and bitumen, and a composite material was prepared. This material was shown to exhibit good protective properties, and it may be recommended to provide anti-corrosive protection of the equipment and installations in oil and gas mining industry. The effect of the amounts of introduced components on the major characteristics of the resulting composition was studied. It is shown that the introduction of a nitrogen-containing modifier (carbamide) into PFO causes a decrease in the content of free phenol and formaldehyde, which is important both from the environmental viewpoint and in relation to the hazardous action of these components on the human organism.