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Thermal decomposition of low-density polyethylene: kinetic study using TGA and DTG data

https://doi.org/10.58224/2619-0575-2025-8-1-1
Abstract
Pyrolysis of low-density polyethylene (LDPE) waste is considered as a highly efficient and promising recycling method. The aim of this work is to investigate the pyrolysis kinetics using three model-free methods (Friedman, Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS)) and two model-fitting methods (Arrhenius and Coates-Redfern). Thermogravimetric (TGA) and differential thermogravimetric (DTG) thermograms at 5, 10, 20 and 40 K min−1 showed a linear curve, which implies the first-order reactions. The kinetic parameter values (E_A and A) of LDPE were calculated at different conversions by three model-free methods, and the average values of activation energies obtained were in good agreement and ranged from 190.23 to 191.89 kJ/mol. These kinetic parameters were additionally calculated at different heating rates using the Arrhenius and Coates-Redfern methods.
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The Review of corrosion protection by nanotubes TiO2 and BTA/TiO2 nanotubes dispersed in Epoxy and proposed method for preparation of anti-corrosion coating from this material assisted by ultrasound

https://doi.org/10.58224/2619-0575-2025-8-1-2
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Abstract
This review presents the corrosion resistance of epoxy coatings containing TiO2 nanotubes and BTA (benzotriazole)-modified TiO2 nanotubes. The purpose of the study is to examine how effectively these materials protect against corrosion on metal surfaces in various environments. The synthesis of TiO2 nanotubes and BTA/TiO2 nanotubes in epoxy coatings offers a promising approach to significantly enhance corrosion resistance while also opening considerable potential for applications in industries requiring high durability and material protection.
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The effect of the complexing components of the washing system on the hydrophilizing properties of the composition

https://doi.org/10.58224/2619-0575-2025-8-1-3
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Abstract
The development of effective and effective formulations of detergents has been an urgent task for a long period. The washing composition includes a large number of various raw materials components that perform certain functions. Today, the market of chemical raw materials has a wide range, which makes it possible to select the necessary components, depending on the required properties and characteristics of the products. Surfactants, which no composition can do without, as well as complexing additives, which not only serve to bind hardness ions during the cleaning process, but also enhance the washing ability of the entire system, are important and mandatory elements of the washing system. Currently, the most popular chelating agents are sodium tripolyphosphate, eth-ylenediaminetetraacetic acid, hydroxyethylenediphosphonic acid, etc. However, based on recent scientific research, it can be concluded that trip. Taking into account this information, such complexes as oxy-ethylene diphosphonic and ethylenediaminetetraacetic acids are beginning to gain great popularity, since they have the necessary set of properties and characteristics for use in detergent formulations, are affordable and simple in the process of technological application. The article describes the influence of the nature of the complexing components that make up detergents on enhancing the cleansing effect and increasing the effectiveness of compositions. For this study, the sedimentation volume method was chosen, which made it possible to evaluate the hydrophilizing effect on the carbon surface in systems with various types of complexing agents. Based on the results obtained, conclusions were drawn about the most effective and suitable chelating agent for this washing system, and the most optimal concentration of the complexing agent was selected.
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Atomic refraction by oxygen as a method for assessing the activity of oxygenates for internal combustion engines

https://doi.org/10.58224/2619-0575-2025-8-1-4
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Abstract
Relevance: it is proposed to evaluate the efficiency or activity of oxygenate compounds by the value of oxygen atomic refraction. This will allow developing new components and additives for the production of motor fuels based on available domestic raw materials.
Objective. Comparison of the efficiency of oxygenate additives and supplements using simple calculation meth-ods.
Methods: a calculation method for determining the molecular and atomic diffraction of oxygenates was used.
Results and conclusions: all oxygenate compounds contain oxygen and the lower the atomic refraction, the more active the vibrations of atoms and electrons in the molecules of oxygenate compounds. Thus, the lower the atomic refraction of oxygen, the higher the activity of the oxygenate. Both molecular and atomic refractions of the main oxygenates have been determined, which made it possible to compare the oxygenates in use and those with potential. An important point is the specific refraction per 1 gram of substance. It is also possible to compare the activity of oxygenates, but in the reverse order: the higher the specific refraction, the more effective the compound is for a spark-ignition engine. For diesel engines, it is desirable to have higher atomic refraction and lower specific refraction per 1 gram of substance, i.e. in the reverse order.
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Overview of developments in the field of biomineralization

https://doi.org/10.58224/2619-0575-2024-7-3-4-33
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 4-33 p.
Abstract
Reactions and biological processes in biobetone represent the integration of biological and technological aspects, which opens up new prospects for research in the field of biomineral-ization of building materials. The object of the study is biobetone, in which various biological and molecular interactions of its constituent components occur. A detailed description of the methodology of the literature research was carried out and the current world research on the use of bioadditives in biobetone was systematized. A review was conducted of research in the field of biomineralization, biocementation and its pathways through which precipitation of calcium carbonate can occur. The hydrolysis of urea and the mechanism of self-healing of biobetone are considered. The problems of self-healing of biobetone have been identified and recommenda-tions for further research have been proposed.
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Synthesis of 4,4’-methylenedianiline (MDA) in the microchannel

https://doi.org/10.58224/2619-0575-2024-7-3-34-48
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 34-48 p.
Abstract
The work is devoted to the method of obtaining 4,4’-methylenedianiline (MDA) in a microchannel. MDA is produced on an industrial scale, mainly as a precursor to polyurethanes. This compound is also used as a hardener for epoxy resins, wire coatings, as well as in reinforced composite materials. The synthesis of MDA is accompanied by high temperature fluctuations, and the limiting factor is the rate of mass transfer. Microfluidics can solve these problems. The microreactors operate in a flow-through design in a laminar flow mode. Due to the small diffusion path of the molecules, the distribution of concentrations and temperatures is fast. This in turn increases the yield of the product, improves reaction control. It is also important in multiphase processes, where the mass transfer process takes place at the phase interface. It is microfluidics that allows precise control of the area of interfacial interaction, which is critical for these processes. However, during the synthesis of MDA, viscosity increases due to the formation of oligomers, which can clog the microchannel. A numerical simulation process was carried out, which revealed the projectile flow in the microchannel, which was also confirmed during the synthesis. A multifactorial experiment has been compiled, which is necessary to determine the optimal synthesis conditions. Parameters such as reaction temperature, component ratio, and residence time varied. The design of the experi-ment was used for successful synthesis. Based on the above parameters, two-dimensional and three-dimensional contour diagrams are constructed, representing mathematical models of the process under study. Due to their combination, the optimal technological parameters of the process were established.
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Investigation of the effect of plasma treatment of carbon felt on its electrochemical properties

https://doi.org/10.58224/2619-0575-2024-7-4-4-12
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 4-12 p.
Abstract
Nowadays, the popularity of vanadium flow batteries is rapidly growing in the world due to higher stability during long-term operation and low costs when creating systems with long battery life. At the same time, research aimed at developing methods to increase the electrocatalytic activity of carbon felt materials in relation to vanadium ions has been largely developed to increase the specific power of flow cells, which are an integral part of vanadium flow batteries. One of the approaches to the modification of these materials is plasma treatment. In this work, two-stage plasma treatment of carbon felt was carried out, first in the medium of one gas, and then in the medium of another gas. Oxygen and nitrogen are selected as the gas. It has been shown that regardless of the order in which plasma treatment is performed, there is a similar trend in the value of the potential difference between the peak of oxidation and the peak of reduction, first it increases in the first stage, and then decreases in the second stage. However, nitrogen treatment at the second stage tends to decrease the potential difference more rapidly (almost 2 times), which we observe in this work.
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Grinding aid for cement clinker

https://doi.org/10.58224/2619-0575-2024-7-4-13-24
 13-24 p.
Abstract
This article presents an analysis of various techniques that contribute to enhancing the efficiency of cement clinker grinding, and their implications for the quality and technical properties of cement.
The study considers not only conventional, but also novel substances used as grinding additives, including coal, carbon black, triethanolamine, rosins, lignins, as well as novel components such as "Lithoplast IP1", InCEM, and MC-GRINDINGPRO 01.
Special attention is given to the most promising grinding intensifiers, particularly "Lithoplast IP1", which has significantly increased mill productivity by 11.1–19.2% while reducing power consumption by 8.9–15.6%. The ar-ticle presents the results of tests that demonstrate the positive impact of this additive on the flowability, grinding and physico-mechanical properties of cement. The benefits of using the "InCEM" intensifier, including the potential to enhance the strength characteristics and optimize the grinding process of cement, are also discussed.
A separate section of the article focuses on the work of researchers M.A. Goncharova, L.V. Zamyshlyaeva, and H.G.H. Al-Surrawi on the use of energy-efficient domestic intensifiers like IP-1 and IM-2. These authors analyze the impact of these additives on the initial strength of cement and grinding efficiency.
According to the results of the study, the introduction of compounds IP-1 and IM-2 into cement has been shown to increase its initial strength by 3.7 MPa and decrease the coefficient of water absorption, thereby improving the quality characteristics of the final product.
Based on these findings, the article emphasizes the significance of grinding intensifiers in enhancing the effi-ciency and quality of cement production, as well as in reducing operational costs and enhancing the reliability of building materials.
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Investigation of chemical power sources on an automated electronic load with controlled parameters

https://doi.org/10.58224/2619-0575-2024-7-4-25-36
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 25-36 p.
Abstract
Hybrid installations for converting fuel energy into electricity are a promising way to provide humanity with affordable energy resources. However, the issue of obtaining reagents (hydrogen and oxygen) with high purity remains one of the most urgent. In this work, the energy characteristics of a hydrogen-oxygen fuel cell in combination with a water electrolyzer were investigated. Membrane-electrode assemblies were formed consisting of a modified membrane based on polytetrafluoroethylene with a platinum-containing component (Pt(30%)/C), as well as an anode and cathode made of carbon fabric and porous nickel doped with technical carbon and graphene. The structural characteristics of the material were studied using the scanning electron microscopy method. For the first time the investigation of hydrogen-oxygen membrane-electrode assemblies energy characteristics was carried out on an automated electronic load AKIP-1375/1E with embedded software. In the developed hydrogen-oxygen fuel cell, a more affordable commercial polytetrafluoroethylene-based membrane was used as a solid polymer elec-trolyte instead of the Nafion membrane, which significantly reduced the cost of developed MEA. As a result of the tests carried out, it was found that the maximum specific power is demonstrated by elements constructed on the basis of an anode and a cathode made of porous nickel modified with graphene.
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Conductive polymers as transparent electrodes: structure, functional characteristics, preparation methods, applications

https://doi.org/10.58224/2619-0575-2024-7-4-37-47
 37-47 p.
Abstract
This paper provides a comprehensive review and analysis of the current state and advancements in major transparent conducting polymers, which are considered promising alternatives to traditional transparent electrodes based on metal oxides, such as indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and fluorine-doped tin oxide (FTO). These polymers possess unique properties, including flexibility, light weight, and ease of integration into flexible and stretchable optoelectronic devices, making them highly attractive for use in organic light-emitting diodes (OLEDs), thin-film transistors, solar cells, sensors, flexible displays, and a range of other applications. The paper presents publication statistics for this research area over the past 10 years based on data from the Scopus database of peer-reviewed scientific literature. It briefly discusses the conduction mechanisms in these polymers, which influence key properties such as electrical conductivity, transparency, and stability under external factors. Various methods for producing these polymers are examined, including chemical deposition, electrochemical techniques, and the incorporation of conductive nanoparticles to enhance functional characteristics. The analysis culminates in a summary table containing data on the transparency, conductivity, and other functional properties of different polymer materials, facilitating their selection for specific applications. Additionally, the paper addresses the prospects and challenges associated with the use of these polymers in flexible electronics, next-generation displays, and other emerging technologies where traditional materials may be less effective or practical.
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