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This paper discusses the effects of the silicon dioxide to aluminium oxide molar ratio, sodium oxide to aluminium oxide molar ratio and concentration of sodium hydroxide on the water absorption and compressive strength of synthesised fly ash-based geopolymers. Geopolymer pastes were prepared using fly ash mixed with an alkaline activator consisting of sodium hydroxide solution and sodium silicate solution. The phase composition, microstructure and chemical bonding of the synthesised products were characterised after 7 and 28 days using X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectroscopy, respectively. The synthesised geopolymer with a silicon dioxide to aluminium oxide molar ratio of 5 and a sodium oxide to aluminium oxide molar ratio of 1.2, activated with 10 M sodium hydroxide, was found to have the highest strength and the lowest water absorption. The compressive strength was observed to increase with increasing silicon dioxide to aluminium oxide molar ratio. A high initial molar ratio of sodium oxide to aluminium oxide enhances the water absorption and decreases the strength of the geopolymer sample. The dissolution of silica and alumina from the starting materials becomes more efficient as the concentration of sodium hydroxide increases.

The rheological behaviour of alkali-activated low-calcium fly ash (AAF) pastes is evaluated. The sodium-based, alkali-silicate activating solutions are proportioned for specific reactive oxide ratios in the paste considering the reactive content of the fly ash. Alkali-silicate activating solutions with different silica contents, with an MS value (the mass ratio silica to sodium oxide (SiO2 : Na2O)) of less than 1.80 are used. The activating solutions exhibit a Newtonian behaviour with higher viscosities at larger silica contents or lower MS. The yield stress and the viscosity of the AAF pastes increase with the viscosity of the activating solution. The zeta potential of the fly ash particles in the alkaline solution with dissolved silica is lowered on decreasing its MS. The yield stress of the AAF paste increases sensitively on decreasing the MS of the activating solution due to the combined influences of reducing the zeta potential of fly ash particles and increasing the viscosity of the activating solution. There are counteracting effects of increasing the viscosity of the activating solution and raising the zeta potential of fly ash, produced by increasing the silica content in the activating solution. The yield stress of AAF paste is less sensitive to the silica content in the activating solution.

Two small molecular dispersants (SMD-1 and SMD-2) with different charge densities of phosphate as the adsorption group were synthesised by the reaction of polyetheramine, phosphorous acid and formaldehyde. The structure and molecular weights of these two synthesised phosphated superplasticisers (PSPs) and a commercial polycarboxylate superplasticiser (PCE) were characterised by Fourier transform infrared spectroscopy and gel permeation chromatography. The dispersing, adsorption and hydration behaviours with the addition of potassium sulfate (K2SO4) to the cement paste were also analysed. The experimental results showed that, compared with the conventional comb-shaped PCE, the linear structure of the PSPs provided lower dispersing ability but better fluidity retention. The addition of potassium sulfate had an obvious negative effect on the dispersing ability of PCE, while the effect on the PSPs was slight. The adsorption isotherms indicated that, with the addition of 2 wt% potassium sulfate, the competitive adsorption between sulfate ions and PCE was enhanced: the saturated adsorption of PCE decreased by 10.37%, whereas the PSPs were less affected, with the saturated adsorption of SMD-1 only decreasing by 2.32%. Isothermal calorimetry measurements showed that the PSPs showed excellent retarding ability and could delay the hydration process of cement.

The effects of two alkanolamines, triethanolamine (TEA) and diethanol-isopropanolamine (DEIPA), on cement hydration were comparatively investigated by several techniques including calorimetry, in situ X-ray diffraction analysis and pore solution analysis. Results show that the cement hydration regime is greatly altered by the alkanolamines, depending on their types and dosages. At the dosage of 0.5%, the aluminate reactions, including the formation of AFt and the reaction of C4AF, are greatly accelerated, and consequently the silicate hydration is retarded. Compared to DEIPA, TEA increases the [Al] in pore solution, probably due to the stronger complexation with aluminate ions (Al(OH)4−), while DEIPA notably enhances the dissolution of C4AF after depletion of gypsum, suggesting a stronger complexation with iron ions (Fe3+). Through a comparison of the hydration of pure alite and cement systems, it is found that the effects of the two alkanolamines on cement hydration are primarily influenced by their impacts on the aluminate reaction.

The influence of potassium oxide contamination of sugar cane bagasse ash (SCBA) on the hydration of cement-based pastes and the compressive strength of mortars was investigated. Three SCBAs with different potassium oxide contents (2.7–12.6%) were used. The SCBA samples were initially characterised by their particle size distribution, BET specific surface area (SSA), pore volume, mineralogy and pozzolanic activity based on the Chapelle method. The hydration of cement-based pastes containing 20 wt% of SCBA was investigated using isothermal calorimetry and chemical shrinkage. The compressive strength of the mortars was evaluated at 3, 7, 28 and 90 days. The pozzolanic activity of SCBA was found to increase with decreasing potassium oxide content due to the higher silicon dioxide content and SSA of the SCBA dosed with a low potassium oxide content in comparison with other samples. The potassium oxide dosage had a limited influence on the paste hydration, except for a slight increase in the induction period observed by calorimetry. Cement replacement with SCBA with a high potassium oxide dosage led to maintenance of the compressive strength in relation to the reference up to 90 days. The mortars with low and medium potassium oxide contents showed good performance in terms of compressive strength, with significant increases compared with the reference after 90 days of curing.

This paper assesses the use and valorisation of two industrial wastes generated at a large scale, which are currently disposed in landfills, as raw materials to produce geopolymers. Specifically, a kaolinitic sludge from the mining industry (CKS), and bottom ash (BA) generated during coal combustion in a thermal power station, were used as aluminosilicate precursors in geopolymer synthesis. The geopolymers were synthesised at 50°C, with a sodium oxide/aluminium oxide (Na2O/Al2O3) molar ratio of 1.0, and different silica/aluminium oxide (SiO2/Al2O3) molar ratios adjusted by manipulating the content of the soluble silicate solution used as the activator. The mechanical strength and reaction products formed during the geopolymerisation process were assessed up to 90 days of curing. The use of CKS as the main component of the precursor blend provides a geopolymer with better mechanical properties due to its higher reactivity than BA. The content of soluble silicates in the alkali activator plays an important role during geopolymerisation, improving the mechanical properties due to the formation of a more reticulated and dense structure. The mortars show a compressive strength higher than 55 MPa after 28 days and low water absorption by capillarity. This elucidates the feasibility of valorising these industrial residues as precursors for geopolymer cements.

The early hydration process of calcium aluminate cement (CAC) was characterised by low-field nuclear magnetic resonance (LF-NMR), isothermal calorimetry (IC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was revealed that LF-NMR characterisation of the hydration process gives results very similar to those of IC; both show that the hydration reaction is faster in about 10–17 h. In addition, the hydration process of CAC could be quantitatively divided into four stages according to the second derivative of LF-NMR signal amplitude. LF-NMR is also used in the study of CAC microstructure. The results of the T2 distribution curve prove that there are mainly two kinds of pores of different sizes in the slurry, and they gradually become smaller, especially in more than 10 h. The weighted average T2 and specific surface area decreased and increased, respectively, due to the gradual densification of the slurry. Owing to the conversion of CAH10 and C2AH8 to C3AH6, the solid specific surface area decreased, resulting in the LF-NMR specific surface area curve slowing down or even decreasing in about 20–50 h of hydration. XRD and SEM results further validate the characterisation of hydrated CAC microstructure by LF-NMR.

The aim of this work was to study the single and combined effects of laboratory synthesised, purified, functionalised multi-walled carbon nanotubes (MWCNTs) and nanosilica (NS) particles on the physico-mechanical and dynamic properties of cement mortars. Portland cement was partially substituted by nanostructured MWCNTs (0.2, 0.4, 0.6, 0.8 and 1.0 wt%), then NS (2, 4, 6, 8 and 10 wt%) and finally both MWCNTs and NS in different ratios. The physico-mechanical and dynamic properties of the composite materials (compressive strength, bending strength, water consumption and initial and final setting times) were measured. The morphology of hardened samples was studied by scanning electron microscopy (SEM) and transmission electron microscopy was conducted to determine the size of the nanoparticles. The results showed that, compared with control samples, the compressive strength of the cement mortars containing MWCNTs increased by 27% at 28 days and the bending strength increased by 9.9% at early age. SEM images showed that the cement mortar containing 0.4 wt% MWCNTs had a more compact microstructure than then the control samples due to the bridging effect of the MWCNTs.

Carbonation has been proven to be a promising way to improve the mechanism properties and durability of steel slag products. Carbonic anhydrase (CA) bacteria can promote the early-age carbonation process of γ-dicalcium silicate (γ-C2S), which is one of the main mineral phases of steel slag. In this study, one kind of alkali-resistant CA bacteria was chosen to investigate its effects on the carbonation process of γ-C2S. Results showed that the bacteria could increase the compressive strength of carbonated γ-C2S by 19.0% when compared with carbonated samples without bacteria. The main products of carbonated γ-C2S were vaterite, calcite and silicon dioxide gel. The addition of bacteria could only accelerate the deposition of calcium carbonate, while hardly changing the types and properties of the carbonation products. The accelerated carbonation was found to reduce the inward diffusion of carbon dioxide. In addition, reasons for the decline of the accelerating carbonation effect were explained by X-ray computed tomography testing results. However, CA bacteria could change the morphology of calcium carbonated during the carbonation process of β-C2S and further accelerate the hydration process of β-C2S. The pore structure could also be refined with the incorporation of bacteria.

Magnesium oxysulfate (MOS) cement is often seen as a ‘green engineering material in the twenty-first century’. However, low mechanical strength is one of the major drawbacks for large-scale applications of MOS cement. In this paper, MOS cement with desirable strength was prepared by adding phosphoric acid. The effects of phosphoric acid on the hydration process, hydration products and microstructure of MOS cement were studied in detail using isothermal calorimetry, X-ray diffraction, Fourier transform infrared spectrometry, mercury intrusion porosimetry and scanning electron microscopy. It was found that the incorporation of phosphoric acid could retard the hydration process and increase the setting time of MOS cement. Furthermore, the incorporation of phosphoric acid was shown to increase the compressive strength through its effect in promoting the formation of 5Mg(OH)2·MgSO4·7H2O. The space-filling properties and directional growth characteristics of 5Mg(OH)2·MgSO4·7H2O contributed to a more compact and uniform microstructure of the MOS cement formed.

In this study, a method known as pre-wetting is applied between the multilayer ceramic investment casting shells to enhance porosity and permeability while sustaining flexural strength. Pre-wetting consists predominately of an aqueous silica binder that improves inter-coat bonding in complex areas. Porosity is developed where the pre-wetting is applied due to the evaporation of the aqueous phase. Results indicate that as porosity increases, both green and fired flexural strength reduce on average by 8.7 - 15.6 % and 18.7 - 28.5 %, respectively, whereas hot strength is increased by 20 - 25 %. Permeability increased by a factor of two when pre-wetting was applied between intermediate coatings and displayed a stepwise increase in intrusion volume in the high-pressure regime through mercury intrusion porosimetry. X-ray microtomography coupled with pore network modelling provided a validation of the increase in the permeability constant. Gas adsorption methods revealed the presence of micropores through the alpha-s method when bilayers of pre-wetting solution were applied.

Water erosion can deteriorate cement-treated bricks. The goal of this study was to investigate the use of multiple biological surface treatments (BSTs) on cement-treated bricks to enhance their resistance to water erosion. Calcite crystals were precipitated on the surface of cement-treated sand bricks by the microbial-induced calcite precipitation (MICP) technique. Multiple BSTs with MICP were used to enhance the properties of the cement-treated bricks further. The experimental results showed that, after a single BST, the flexural strength of the cement-treated bricks increased from 500 kPa to 750 kPa and the compressive strength increased from 3000 kPa to 4000 kPa. Erosion and water absorption were reduced by 71.2% and 16.3%, respectively. Compared with cement-treated bricks without any BST, the cement-treated bricks with triple MICP BSTs showed increases of nearly 140% and 100% in peak flexural and compressive strength, respectively. In addition, the triple BSTs resulted in 32% less water absorption compared with cement-treated samples without any BST. The surface of cement-treated bricks with triple BSTs was found to resist accelerated erosion over a 60 min time period. Overall, the results showed that BST can strengthen the erosion resistance of cement-treated bricks.

Chloride-based accelerators are widely used to accelerate cement hydration; however, there is no focus on the effect of the interaction between Cl− and SO42− on cement hydration. Hence, the interaction effect between initial gypsum and sodium chloride (NaCl) in the cement hydration process was investigated. Isothermal calorimetry, scanning electron microscopy, thermogravimetric analysis, X-ray diffraction and inductively coupled plasma spectroscopy were used to evaluate the hydration process of cement paste. Moreover, a thermodynamic model and boundary nucleation and a growth model were applied to calculate the hydration products and describe the hydration process, respectively. It is clear that sodium chloride can accelerate cement hydration, but as the incorporated sodium chloride increases, the acceleration effect is weakened. The incorporation of chloride salts will promote the dissolution of minerals and increase the growth rate. In the early stage of hydration, the formation of ettringite precedes formation of Friedel's salt, owing to the fact that tricalcium aluminate (C3A) favours binding with SO42−, which can be demonstrated by the change in ion concentrations and the evolution of hydration products. The formation of Kuzel's salt depends not only on the chloride concentration but also on the hydration time.

Metakaolin-based geopolymers (MKGs) containing different contents of MS expansive agents (EAs) were prepared by alkali activation. Different mechanical testing methods for differently shaped samples were used to evaluate the bond properties of the MKGs. A cement substrate with a circular hole in the middle was used as a permeability test specimen to assess bond by checking the bond appearance and testing the permeability. According to the results of the mechanical properties and penetration tests, the MKG with 4% MS-3 exhibited the best bond properties. The EAs significantly improved the expansion properties and reduced the tensile stress at the interface; these were the main reasons for the improvement in bond properties between the MKG and cement stone. Favourable bond property is an important basis for MKG as an inorganic crack repair material.

Comb-like polycarboxylate is a superplasticiser possessing a high water reducing rate and excellent molecular design, and has been widely used in the concrete industry. Most research studies have adjusted the effect of the superplasticiser by improving the groups on the superplasticiser molecular chain, but few studies have been carried out that change the structure of the comb molecular chain. AB2 monomer was prepared by the Michael addition reaction of diethanolamine and methyl acrylate, and hyperbranched polymer was prepared with trihydroxypropane as the core. In this paper, an advanced hyperbranched polycarboxylate, which was modified by a hyperbranched polyamine-ester, was designed as a superplasticiser. The hyperbranched polycarboxylic acid superplasticiser has the advantage of improving the rheological properties of cement slurry and the strength of mortar test blocks, compared with the traditional polycarboxylate superplasticiser; this is attributed to the hyperbranched polymers that provide hydroxyl groups and enhance the molecular spatial structure.

The influence of ongoing cement hydration and multiple microcrack formation on the electrical impedance of an engineered cementitious composite (ECC) is presented. Impedance measurements were obtained over the frequency range 20 Hz–1 MHz and displayed in the Nyquist format. In addition, the permittivity and conductivity were de-embedded from the measured impedance and presented in both time and frequency domains to elucidate the nature of conduction and polarisation processes. It was found that, over a curing period of 90 days, the ECC displayed a classic impedance response. Both conductivity and relative permittivity were found to be frequency dependent due to bulk relaxation processes operating within the composite. Tensile straining was shown to result in a detectable change in the impedance response, but retained a similar overall profile. When presented in the frequency domain, a downward displacement in both conductivity and relative permittivity profiles was evident with increasing tensile strain. It is shown that the relative permittivity at the high-frequency end could be exploited as a potentially useful indicator for strain/damage detection. The influence of microcracking on the piezo-resistive response of the composite is discussed based on crack patterns obtained from both visual observations and digital image correlation.

The adsorption behaviour and dispersing capability of structurally different polycarboxylate superplasticisers (PCEs), with various carboxylic densities, was investigated in the presence of sulfates. The effect of sulfates on the early cement hydration evolution in the presence of PCEs with different carboxylic densities was also analysed. It was found that a higher proportion of carboxylate groups in the PCE backbone contributed to more intense adsorption of PCE onto cement grains, which contributed to lower sensitivity to the competitive adsorption of sulfate ions and hence produced higher resistance to the negative impacts of sulfates on fluidity and zeta potential. The addition of sulfates partially eliminated the retardation effect of PCE on cement hydration and boosted the nucleation of hydrates with increased cumulative hydration heat and higher heat evolution peak in the acceleration period. A higher concentration of sulfates led to a greater acceleration effect on cement hydration. However, PCEs with higher carboxylic density showed enhanced resistance to the impacts of sulfates on cement hydration.

The effects of curing temperature (23, 40 and 50°C) on the mechanical properties of cement paste and concrete containing glass powder (GP; 0, 10, 20 and 30%) as a cement replacement are investigated. In addition, a new mixing method (NMM) is studied, which involves soaking the GP before adding it to the concrete. The results show that an increase in the immersion time decreases the Na+/Ca2+ ratio for mixes with 10% GP. The amount of dicalcium silicate, tricalcium silicate and portlandite decreases with the increase in curing temperature, indicating the activation of the pozzolanic reaction. The results show a significant increase in the density and compressive strength early in the curing process due to the higher pozzolanic reaction of GP at elevated temperatures. At higher temperatures, the differences between the control and the GP mixes become smaller. The NMM enhances the mechanical behaviour of concrete compared with conventional mixing. An increase in the compressive strength of 30% is obtained at 10% GP.

The aim of this study was to improve the acid resistance of a metakaolin-based geopolymer (MKG) by substituting metakaolin with calcium aluminate cement (CAC). The CAC was added at weight ratios of 5% and 10%. The raw materials were activated with a mixture of sodium hydroxide solution and sodium silicate solution. The cured MKG mortars were immersed in a sulfuric acid solution with a pH of 2 for 75 days. Tests for the volume of permeable voids, unconfined compressive strength (UCS) tests, thermogravimetric analysis and Fourier transform infrared spectroscopy were conducted before sulfuric acid immersion. It was found that the addition of CAC facilitated geopolymerisation and reduced the volume of permeable voids of the MKGs. Changes in UCS, ultrasonic pulse velocity, mass and length were monitored to evaluate acid resistance. It was found that the addition of CAC dramatically improved the acid resistance of the MKG due to the reduced volume of permeable voids and enhanced neutralisation capacity. The mixture with 10% CAC showed the lowest deterioration.

Various strategies have been developed to mitigate the autogenous shrinkage of cement-based materials (CBMs), including internal curing and shrinkage compensation. However, the sole use of internal curing or shrinkage compensation is insufficient in many cases. In this study, magnesia-based expansive additives (MEAs) coupled with a superabsorbent polymer (SAP) were investigated as internal curing agents to mitigate the autogenous shrinkage of cement pastes. The internal relative humidity (RH), autogenous deformation and compressive strength of cement pastes containing two different types of MEAs and SAP were examined. The results showed that, with the incorporation of SAP, the RH in the cement paste was maintained at a higher level than that in cement pastes without SAP, and hence autogenous shrinkage was reduced. The combination of SAP and MEA provided very effective compensation for the autogenous shrinkage of cement paste. Moreover, the cement paste containing 8 wt% MEA and 0.2 wt% SAP produced a gentle expansion of 111 microstrain rather than shrinkage. This was attributed to the increased hydration degree of magnesia owing to the additional water supply provided by the SAP. This study provides a novel and efficient way to mitigate the autogenous shrinkage of CBMs.

Cationic asphalt emulsion (CAE) is a type of organic latex that could be used to modify cement hydration products in order to improve the performance of cement paste. In this study, different methodologies were used to investigate the influence of CAE on the process of cement hydration. The results showed that with an increase in the mass ratio of asphalt to cement, the setting time of the cement paste was prolonged while the compressive strength and water absorption of the cement mortar showed obvious reductions. Other techniques were also used to investigate the cement hydration process and the microstructure evolution caused by the addition of CAE, including conductivity measurements, 29Si nuclear magnetic resonance, low-field nuclear magnetic resonance, measurements of chemically bound water and field emission scanning electron microscopy. It was found that the formation of cement hydration products was delayed with an increase in CAE and the microstructure was affected by the CAE in that the pores were separated by asphalt film and the total porosity decreased.

Fast pyrolysis of hydrolysis lignin was studied in fluidized bed units. Hydrolysis lignin, a bioproduct from the lignocellulosic ethanol production process (St1 Cellunolix), was processed in bench scale bubbling fluidized bed (BFB) and pilot scale circulating fluidized bed (CFB) units. Utilization of steam and ethanol as hydrogen sources was tested in a BFB unit. Major technical challenges identified were related to slow reaction rates of lignin degradation and the rapid secondary reactions in the vapor phase resulting in deposit formation and pressure buildup in product gas lines. The carbohydrate content of hydrolysis lignin had a clear correlation to its processability. More challenges with clogging and bed agglomeration were observed with lignin feedstock having lower carbohydrate content. The challenges with the bed agglomeration in the BFB unit were overcome by adding a rapidly rotating mixer in the reactor to break the agglomerates. With the CFB unit, bed agglomeration was not a problem, due to high gas velocities and forces applied to sand and lignin particles. In the BFB unit, the screw feeder was cooled and no significant melting problems were observed. In the CFB unit, melting problems were avoided by feeding the raw material in the cold section of reactor. However, severe increases in the pressure buildup and deposit formation rates were observed in both units. Steam and ethanol was tested, separately, in the BFB unit, to provide excess hydrogen in the system. Based on the product analyses both added hydrogen into the system, but hydrogen ended up mostly in the gas phase. To enhance the hydrogen transfer to the organic liquid, a catalyst active in hydrogen transfer is probably needed.

The non-isothermal analysis of materials with the application of the Arrhenius equation involves temperature integration. If the frequency factor in the Arrhenius equation depends on temperature with a power-law relationship, the integral is known as the general temperature integral. This integral which has no analytical solution is estimated by the approximation functions with different accuracies. In this article, the rational approximations of the integral were obtained based on the minimization of the maximal deviation of bivariate functions. Mathematically, these problems belong to the class of quasiconvex optimization and can be solved using the bisection method. The approximations obtained in this study are more accurate than all approximates available in the literature.

The article highlights the results of a study of the situation with official investigations into criminal offenses related to the enforced disappearance of persons in the context of armed aggression in eastern and southern Ukraine. The example of individual criminal proceedings presents some systemic problems that arise during the investigation of the facts of disappearance and suggests possible ways to solve them. There are several «blocks» of problems that lie in the field of criminal law, criminology, and criminal procedure. The points of view of scientists and practitioners on this problem are highlighted. It is concluded that Ukraine, in today’s conditions, needs to take measures aimed at improving the legal mechanisms of observance and protection of the right of persons staying in its territory to freedom from enforced disappearance, as well as intensifying law enforcement agencies to prompt, complete and impartial investigation of such facts, their proper qualification, search for victims, identification of those responsible for their disappearance, ensuring that victims receive timely and adequate compensation. The methodological basis for writing the article was a dialectical-materialist method, as well as the set of general scientific and special methods and techniques of scientific knowledge.

The purpose of the article is to consider the main international regulations on the introduction and operation of payment systems in Europe, as well as national legislation providing for the development of payment systems in Ukraine. The research methodology includes the following general and special legal methods: axiological, historical and legal, formal and logical, comparative and legal, as well as the methods of analysis and synthesis, induction and deduction, summarization. Results of the research. The main international regulations on the formation and functioning of payment systems in the European countries, which became the basis for the development of relevant legislation of Ukraine in this area, are analyzed. The legal acts that currently regulate this issue in our country are considered, as well as Draft Laws aimed at resolving existing problematic issues in the payment systems market are examined. Practical meaning. The positive dynamics of the development of the Ukrainian payment legislation in accordance with the needs of the market and changes in the payment habits of the population are established. Value / originality. Emphasis is placed on the need for the further measures by the National Bank of Ukraine in order to harmonize national legislation with the European regulations in this area.

The aim of the study was to examine the positions of various social groups, reflecting the controversial and contradictory aspects of the process of identity construction in post-Soviet Russia and the factor of memory politics. The article reveals the characteristics of the post-Soviet identity-building process and the related politics of memory under the century-end systemic transformation that has launched a new existential project in Russia. Collective identity is formed in a new social space: the global dichotomy of globalization and localization. Methodologically, it is a documentary research close to the analysis of discourse. The process of transition from the Soviet Union to post-Soviet space and the construction of the new state on the ruins of the socialist empire will keep the problems of a new identity and the politics of memory relevant soon. It is concluded that thirty years after the liquidation of the socialist project, the crisis of collective identity in Russia and the "battle for history" and a new Russian national unity are not over. However, persistent social atomization and conflict-triggering narratives of various socio-cultural communities and ideological groups persist.

The aim of the research is to reveal political and legal aspects at international level in the field of citizens' participation in the fight against crime. Attention is paid to the most common forms of public participation: patrolling; provide information on criminals or criminal acts committed; participation in anti-corruption measures; assistance in the resocialization of offenders; aiding victims of crime; strengthening the security of one's own property; participation in information on anti-criminal measures. Methodologically it is a documentary research. In conclusion, the benefits of public participation in crime prevention, based on international crime prevention, can be divided into two groups: basic and additional. The main advantages are reduction of crime and delinquency; improve security in relevant areas of cities; reducing citizens' fear of crime; strengthening the service function of the police forces in relation to the inhabitants of territorial communities; improve police partnerships with the public.

The article aims to explore the relationships that arise with respect to intellectual property rights in sports. The objectives of the article are to establish points of contact between intellectual property law and sports, as well as a detailed analysis of relevant public relations in terms of intellectual property law and sports law. To achieve the objectives of the article, the authors used a number of scientific methods, among which the main methods are analysis, synthesis and comparative-legal method. The authors of the study concluded that modern sport is developing in close intertwining with intellectual property rights, because only in this way can a sports spectacle be conveyed to a wide range of spectators and consumers in a broad sense. In addition, the range of points of contact between intellectual property and sports law is constantly growing and such can now be called not only patents and trademarks in sports, but also copyright, "image" rights, know-how in sports and the like.

Civil legal and civil-procedural legal relations are one of the most significant categories in the science of civil and civil-procedural law, the relationship of which is not fully studied in science, so it is necessary to reveal the essence of their correlation and find differences between them. In the legal doctrine, there is a small number of works that would reveal the content of the relationship of such legal relations, the algorithm and criteria for their comparison are not fully developed, the scientific approaches to the separation of the criterion of their comparison are not revealed. In this regard, it is necessary to fulfil the doctrinal study of civil legal and civil procedural legal relations, both separately and jointly, using a particular criterion. The following methods were used in the study of the relationship between civil legal and civil-procedural legal relations: formal-legal, generalization, method of analysis of normative documents, articles and monographs, comparative legal method. As a result of the research, the connections between such categories as civil legal relations and civil procedural legal relations were clarified, and the criteria for their comparison were singled out.

In all areas of the legal world there are higher aspirations, which represent legal values to be protected, like the justice, the common good and legal security stand out. The present work was proposed to analyze if the Ecuadorian Legislator, in its process of construction and promulgation of the criminal law regulating against the unfair competition, incorporated these three values into it. Regrettably, the results show an apparent absence of the three legal values in criminal law, leaving legal operators at a disadvantage in view of the need to control this type of crime and society, awaiting compliance. Through an exercise of legal hermeneutics, the study starts from a real problem in the Ecuadorian legal system of the criminal law against of the unfair competition, which demands to be discussed in the search for the State to take the necessary measures to solve this problem.

Due to the development of the information society, countries face the task of effectively regulating the relevant social relations. The mechanisms of such regulation should correspond to the specifics of such relations. Digitization is one of the modern methods of legal regulation, which is the use of information technology at the state level. The existing scientific achievements on digitalization processes need constant improvement, which corresponds to the specifics of this field. The object of research is digitalization in law in the light of international experience. The article aims to study and analyze digitalization in law in the international legal aspect. The following methods were used during the study: systemic, systemic-functional, comparative, sociological, analysis, synthesis, analogy, observation, classification, and statistical analysis. The article analyzes the phenomenon of digitalization, identifies the main approaches to understanding it. On the example of international experience (such countries as France, Germany, Italy, Georgia, Greece, and Great Britain), the mechanisms of using digitalization in public administration are determined, the legal regulation of informatization is analyzed. Also, based on the study and analysis of doctrinal teachings of international information experience, it is proposed to improve the domestic legal mechanism to ensure the effective functioning of public relations.

The aim of the research is a comprehensive analysis of the problem of protecting property rights against a terrorist threat and finding ways to solve it. The article deals with the main problems of protection of property rights under conditions of external military aggression in Ukraine. The authors, with the example of a separate case, analyses the problematic aspects of renewing and granting property rights to citizens residing in the temporarily occupied territory of Ukraine. Methodologically, it is a documentary research. It is concluded that the law and judicial practice of the protection of property rights in the example of the right to compensation for damaged homes may prove insufficient on its own. The weaknesses of Ukrainian legislation in compensation for damage caused to citizens in conditions of armed conflict and terrorist activity are discussed in detail. Finally, it emphasizes the role of transitional justice in improving the law and practice of resolving disputes overcompensation for moral and material damage under the conditions of occupation of certain territories of Ukraine.

The scientific article is devoted to a comprehensive understanding of international legal, procedural, and organizational problems of investigation of war crimes committed during the military conflict in the south and east of Ukraine. It develops the author's concept of investigation of war crimes committed during the armed conflict, scientifically substantiated theoretical provisions and specific patterns that are manifested in the field of legal support, organization of investigation, collection of evidence, methods of investigation of crimes of this type. It is concluded that there is a need to specify the components of war crimes in national legislation. Recommendations for further improvement of criminal and criminal procedure legislation of Ukraine in order to fulfill the state's international obligations in the field of international humanitarian law are given.

Using the documentary research methodology, the aim of the article was to study Iran's criminal policy towards money laundering in its banking system. A number of measures have been taken in the Iranian legal system to combat money-laundering, the most important of which is the adoption of the anti-money-laundering law in 2007 and its executive regulations in 2009. With the enactment of this law, the crime of money laundering officially entered the Iranian legal system with its own special and independent title. By way of conclusion, it is evident that various governmental and judicial institutions have made the fight against money-laundering one of their main objectives and tasks. Meanwhile, the role of the National Audit Office has also been prominent, and it has made numerous efforts, both nationally and internationally, to identify cases of money laundering, eliminate money laundering and ultimately combat it effectively and efficiently.

Effective counteraction to corruption remains relevant in some countries of Eastern Europe and the former Soviet Union, given that manifestations of corruption are a real obstacle to the realization of human rights, social justice, economic development and jeopardizes the proper functioning of a market economy. However, if such countries of the region, such as Poland, succeeded in ensuring the implementation of an effective anti-corruption policy, a number of post-Soviet countries, in particular Ukraine, faced significant obstacles to overcoming corruption and effectively implementing national anti-corruption policies. Therefore, within this article, a comparative legal analysis of the anti-corruption legislation of these countries has been carried out. The state of implementation of national anti-corruption policies and the formulated conclusions, which provide answers to the questions of improving the implementation of national anti-corruption policy, in particular Ukraine, are considered. Thus, the existence of modern national anti-corruption legislation that best meets the requirements and recommendations on which the state relies on relevant international treaties can be the key to successful anti-corruption efforts.

The article examines the legal status of legal entities of public law as participants in civil circulation. Both general and special research methods were used, which were determined by the purpose of the article, taking into account the object and subject of the research. To study the above-mentioned civil law relations in their interconnection and development, the dialectical method was used. The comparative legal method was used to analyze the world experience of legal regulation of the status of legal entities of public law in foreign legislation and the doctrine of law, in particular, in the legislation of the CIS countries. Results showed that legal entities of public law are organizations; as legal entities; have the characteristics of a legal entity: organizational unity, the presence of separate property, acting in circulation on their own behalf, independent civil liability. In addition to the general features of a legal entity, legal entities of public law also have special features that characterize them as participants in civil turnover. It was concluded that legal entities of public law are a type of legal entity, are created in the administrative order by the state and have targeted legal capacity.

The study is relevant as the category of "national security" is multilevel. The work reveals the characteristics and components of this system. The concept of national security exists all over the world. It is one of the most important types of security and is studied by academics from different countries. Furthermore, the concept of national security means a set of scientific and theoretical ideas, opinions and views that dominate in each society and is a subjective reflection of objective ties and national security relations in the public consciousness. From a documentary methodology the article aims to study the legal nature and essence of national security. It is concluded that the genesis of this concept tracks the dialectical interaction of objective and subjective factors. The legal regulation of national security is a comprehensive and multifaceted process based on a complex system of legal rules and regulations. The most significant ones are analyzed in this study. However, academics have not considered all the legal components of national security.

The aim of the article is to analyze theoretical and methodological provisions related to the definition of directions and principles of implementation of a systematic approach to the use of optical research methods, in particular micro-objects. Subject of research is substantiation and formulation of the classification characteristics of such systematic approach, considering the requirements of forensic techniques. Methodology: The study applies such methods of scientific knowledge as dialectical method, system and structural method, logic and legal method, methods of systematic analysis, logical method. Research results: The article studies the problematic issues of a systematic approach to the choice of scientific and technical methods and means for micro-object examination. Practical consequences: The authors argue that optical methods of the micro-object examination require classifying and systematizing to provide a holistic view of their potentials, as well as the nature of the information that can be obtained about the object being examined. Value / originality: The analysis of clarified classification characteristics and requirements for examination methods in forensic science enables to propose the algorithm of the systemic approach to the creation of the open system classification of methods of micro-object examination and to make justified conclusions.

The impact of three different organosilicon compounds: poly(dimethylsiloxane) (PDMS), potassium methylsiliconate (MESI) and triethoxyoctylsilane (OTES), used as integral admixtures, on Portland cement hydration has been investigated by isothermal calorimetry and DTA-TG analysis. The silicon-based compounds are widely used as internal hydrophobic agents added into batch water; therefore, their effectiveness was investigated by means of capillary water absorption test. The isothermal calorimetry was used to measure the rate and amount of heat released during ordinary Portland cement hydration with integral organosilicon admixtures at 20 °C, 30 °C, 40 °C and 50 °C. It allowed to determine the activation energy as well. The results indicate that used admixtures (except MESI admixture) decrease in the rate and amount of heat release during cement hydration. In addition, it is noticeable that the addition of MESI admixture significantly prolongs the induction period and delays hydration. In contrast to MESI and OTES admixtures, PDMS-based admixture does not affect significant on the activation energy. DTA-TG analysis had shown differences between reference sample and samples containing organosilicon admixtures during thermal decomposition, in terms of the amount of moisture and bound water, as well as Ca(OH)2 or carbonates. The results presented in this paper enable a better understanding of the interactions between the organosilicon integral admixtures and the cement matrix. The study shows the effect of integral admixtures on cement hydration and thus the potential effect on the final properties of the cement-based material.

The article examines the place and role of the Constitutional Court in the system of public powers in the doctrinal understanding of the concept of human rights and constitutionalism. The Constitution of the Russian Federation establishes the basic constitutional and legal principles that are fundamental to substantive and procedural law. Judicial constitutional review, as the experience of European countries shows, is the most effective in protecting the Constitution. The principles of law applied to the doctrinal assessment of the place and role of the Constitutional Court in the system of public powers constitute a rather dynamic legal concept. The methodology is based on the legal system, public relations, and the political-state course, which, like all fundamental ideas, change, affect legal awareness and establish new requirements for legal regulation and the formation of an appropriate mechanism. The article concludes that the most important condition for the implementation of the prerogatives of the judiciary to administer justice in the consideration and resolution of specific cases, with emphasis on the study and evaluation of evidence. It is the evidence that serves as the basis of information for the court's findings in the case.

The study was conducted to identify the environmental component in the development of agrotourism and its impact on the psychological state of society in the COVID-19 pandemic. The experience of European countries shows the environmental, economic, and social benefits of agrotourism. The methodological basis of the study is the general scientific methods of cognition and social processes (analysis, synthesis, generalization, classification) together with sociological methods of obtaining empirical data. The National Tourism Organization of Ukraine has declared 2020 as the year of green rural tourism, an important component from which agrotourism arises. It is concluded that, la peculiarity of the development of agrotourism in Ukraine at the current stage is the acquisition of innovative forms of organization according to the growing needs of consumers, the efficient use of the natural, ecological, socioeconomic, and historical-cultural potential of the territory and the achievement of the required level of profitability. The situation of crisis and instability is accompanied by the presence of uncertainty associated with the COVID-19 pandemic; the need to form the concept of tourism development 4.0; introduction of ICT and development of innovative technologies in agrotourism in rural areas; training of professionals in the field of agrotourism.

The objective of the study is to analyze the rule of law in the context of the implementation of reforms of the judiciary, the judiciary, and related legal institutions as a direction to ensure the accessibility of administrative justice in Ukraine, revealing its relationship and interdependence. The study found that the availability of administrative procedures is provided by the requirements of all these generic subsystems of the principles that determine modern standards of activity in European countries. The methodology includes a comprehensive analysis and generalization of the available scientific and theoretical material, as well as the formulation of relevant conclusions. During the research, scientific cognition methods were used: terminological, logical-semantic, functional, system-structural, logical-normative, comparative. They highlight in the conclusions that the study found that the amendments to the Constitution of Ukraine in the context of judicial reform made it possible to revise the classical principles of the judiciary, but there are still important unresolved aspects to ensure full compliance with the rule of law, its specification in the constitutional provisions and legislative acts of Ukraine of substantive and procedural content, among other aspects.

In modern conditions of development of public relations complication of activity of law enforcement agencies is observed. This is due to new challenges in the law enforcement system, including the fight against high levels of the organization and the criminal professionalism of corrupt individuals. Because of this, it is challenging for operational units to identify specific facts of illegal actions with the help of operational and investigative measures. At the same time, the fight against crime by establishing high quantitative indicators of disclosure remains one of the principles of law enforcement in Ukraine, including sometimes deviating from those means established by law. Therefore, the problem of provoking bribery is relevant for scholars of the legislator and law enforcement. The object of the study is criminal liability for provoking bribery. The research methodology consists of such methods as the dialectical method, analytical method, historical method, method of analysis of legal documents, articles, and monographs, method of generalization, comparison, synthesis, and modeling method. The authors identified the features of such liability to clarify the problematic issues of qualification of provoking bribery, and to distinguish the distinctive features of prosecution from other types of crimes.

Based on the provisions of criminal procedure theory and criminology, the problems of international legal assistance are revealed during the pre-trial investigation for crimes of corruption in the field of official and professional activities. Special attention is paid to identifying the details of evidential activities in criminal proceedings for offences related to the provision of public services during a special pre-trial investigation (in absentia). The methodological basis of the article is a set of general and special scientific methods of legal cognition. In particular, the concept of pre-trial special investigation is formulated, its functional purpose is defined, characteristics of the carrying out of separate investigative actions (search) during the special pre-trial investigation for corruption offences. Attention is paid to issues of international cooperation to identify and search for assets in these criminal proceedings. Other problems are revealed in the use of international legal assistance to obtain evidence during the investigation of these crimes. It is concluded that a problem that arises during international cooperation during the preliminary investigation is the uncertainty in international rules on the provision of mutual legal assistance.

From a documentary perspective the article addresses issues such as the collapse of the Soviet Union, separatism in the USSR and the existence of similar destructive processes in modern Russia. Special attention is paid to the role of the media in the collapse of the USSR. The goal was to find out whether the collapse of the Soviet Union and the rise of New Russia were inevitable. Consequently, the additional objectives of the article are to identify the main reasons for the collapse of the USSR, to draw an analogy with the situation in modern Russia, to analyze propaganda techniques by examining the Moscow News newspaper, and to study and generalize the main problems of inter-ethnic dialogue in the Soviet and post-Soviet space. The relevance of the topic is justified by the lack of a unified view in the community of experts on the causes and consequences of the collapse of the USSR, as well as by the lack of a unified assessment of the period of Perestroika and the inevitability of the transition from socialism to capitalism in Russia. It is concluded that in the geopolitical phenomenon of the collapse of the USSR occupies a special role the national and international media dimension.

This article analyzes institutional, procedural, and behavioral attributes, principles, and indicators of typology of challenges and threats caused by the coronavirus pandemic in the world. The analysis shows that most countries faced external shocks caused by COVID-19 in the absence of a universal social protection system, a reliable health system, a plan to achieve carbon neutrality by 2050, or a stable real economy with quality jobs. Economic security has become an important priority, although this is not about social protection, but also about supporting strategic sectors of the economy. Balancing on the brink of the needfor socialprotection, on the one hand, and the rise of austerity, on the other, governments opted for severe economic restrictions. Thus, through the naaliticos method the authors describen the main geopolitical trends that will be the basis for the construction of a new world order that awaits us on the other side of the pandemic, including deglobalization, the geopolitical rise of China, the severe restrictions on human and civil rights, the intensification of the interstate armed forces, in context of growing conflicts and local protests.

The thermal gravimetric analysis (TG) is a common method for the examination of the carbonation progress of cement-based materials. Unfortunately, the thermal properties of some components complicate the evaluation of TG results. Various hydrate phases, such as ettringite (AFt), C–S–H and AFm, decompose almost simultaneously in the temperature range up to 200 °C. Additionally, physically bound water is released in the same temperature range. In the temperature range between 450 °C and 600 °C, the decomposition of calcium hydroxide and amorphous or weakly bound carbonates takes place simultaneously. Carbonates, like calcite, from limestone powder or other additives may be already contained in the noncarbonated sample material. For this research, an attempt was made to minimise the influence of these effects. Therefore, differential curves from DTG results of noncarbonated areas and areas with various states of carbonation of the same sample material were calculated and evaluated. Concretes based on three different types of cement were produced and stored under accelerated carbonation conditions (1% CO2 in air). The required sample material was obtained by cutting slices from various depths of previously CO2-treated specimen and subsequent grinding. During the sample preparation, a special attention was paid that no additional carbonation processes took place. As reference method for the determination of the carbonation depth, the sprayed application of phenolphthalein solution was carried out. Microscopic analysis was examined to confirm the assumptions made previously. Furthermore, the observed effect of encapsulation of calcium hydroxide by carbonates caused by the accelerated carbonation conditions was examined more closely.

The objective of the study was the phenomenon of doublethinking as a special form of anomic thinking. Doublethinking leads to a distortion of the perception and appreciation of political reality, which is expressed in the inaccuracy of information about the surrounding world. In methodological terms, the ethical theory of Alasdair McIntyre and the idea of doublethinking of G. Orwell were used. This allows us to conclude that in our time there is a crisis of values, which consists in the simultaneous presence of two normative-value systems in the human mind. One of them is inherited by the idea of modern humanity from Christianity; the second, which is preferred by many, was created by utilitarianism. This makes it possible to formally recognize, in words, socially approved values, norms and objectives, while at the same time devaluing them in actions, replacing them with the principle of personal gain. As a result, a new political language is emerging newspeak. The desire for constructive public action, mutual help, respect, and altruism is replaced by corruption, hypocrisy, opportunism, the decline of professionalism and productivity, the negative selection of political elites.

In this study, using the descriptive-analytical method, we discuss the main factors in the formation of the Yemen crisis, as well as the attitudes of the two Arab states and of the two neighboring countries, Saudi Arabia, and the United Arab Emirates, in the Yemen crisis. It is concluded that this crisis stems not only from the role of local actors, but also from the role of regional and global actors, who played a decisive role in shaping and exacerbating the Yemen crisis. Regional players in the post-2015 crisis include the United Arab Emirates and Saudi Arabia, which showed contradictory behavior. Saudi Arabia's targets in its attack on Yemen have a greater military and security dimension. The political and economic objectives of the United Arab Emirates, which is Riyadh's most important ally in this war, have been at a different level from those of Saudi Arabia. This can be seen in Abu Dubai Crown Prince Mohammed bin Zayed's aspirations to expand his country's influence, to become a major player in the region.

The article is devoted to the analysis of some features of the investigation of football hooliganism. The current state and trends of football hooliganism are considered (including during the COVID-19 pandemic). The main problems faced by the investigation authorities during the detection and investigation of football hooliganism have been identified. In the process of working on the article, the scientific literature on informal youth groups, the fight against extremism, the investigation of group crimes of football fans was analyzed. The purpose of the study is to identify and study the features of the investigation of hooliganism committed by football fans. The object of research is the peculiarities of the investigation of hooliganism committed by football fans. During the writing of the article, the following methods were used: observation, analysis, synthesis, comparison, generalization, extrapolation, modeling, and information approach. As a result of the conducted research, the modern tendencies of football hooliganism are defined. Emphasis is placed on the peculiarities of the transformation of football fans. The principal problems of detection and investigation of football hooliganism are outlined, recommendations for prevention and counteraction to crimes committed by football fans are developed.