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Full-Text Articles in Materials Science and Engineering

Patterns Of Alcolysis Of Secondary Polyethylene Terephthalate With Diethylene Glycol, Juraev B. Juraev, Murafar G. Alimuhamedov, Ravshan I. Adilov, Bobir B. Aykhodjaev, Olga S. Kukurina Jun 2026

Patterns Of Alcolysis Of Secondary Polyethylene Terephthalate With Diethylene Glycol, Juraev B. Juraev, Murafar G. Alimuhamedov, Ravshan I. Adilov, Bobir B. Aykhodjaev, Olga S. Kukurina

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work was to study the process of alcoholysis of recycled polyethylene terephthalate with diethylene glycol, as well as the structure and physicochemical properties of the final product. IR and PMR spectroscopy were used to study the structure and identify the structure of the products of RPET alcoholysis with diethylene glycol. As a result of  studies of the alcoholysis of polyethylene terephthalate-containing waste with diethylene glycol, a wide range of hydroxyl-containing oligoesters was synthesized. The possibility of changing their physicochemical properties by adjusting the process parameters was demonstrated. This makes it possible to synthesize hydroxyl-containing oligoesters with …


Synthesis And Infrared-Spectroscopic Study Of Complexes Of Selected 3d-Metals With 2-(2-Pyridyl)-Benzimidazole, Farangiz A. Khujayeva, Hakima A. Alikulova, Shahzoda G. Allamurodova, Mushtariybonu M. Sunnatillayeva, Shahlo Sh. Daminova Jun 2026

Synthesis And Infrared-Spectroscopic Study Of Complexes Of Selected 3d-Metals With 2-(2-Pyridyl)-Benzimidazole, Farangiz A. Khujayeva, Hakima A. Alikulova, Shahzoda G. Allamurodova, Mushtariybonu M. Sunnatillayeva, Shahlo Sh. Daminova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study was to synthesize and systematically investigate the coordination compounds of several 3d metals with 2-(2-pyridyl)benzimidazole (2-PBI) using infrared (IR) spectroscopy. Complexes of copper(II), nickel(II), and cobalt(II) with the general formula [M(2-PBI)3](ClO₄)₂were successfully synthesized. Based on the analysis of the IR spectra, it was established that the 2-PBI ligand coordinates to the metal ion in a bidentate manner through the nitrogen atoms of the benzimidazole and pyridyl rings. The shifts of the ν(C=N) and ν(C–N) stretching vibration bands, as well as the appearance of new bands in the 623–485 cm⁻№ region corresponding to ν(M–N) and vibrations, …


Production Of Organo-Mineral Fertilizing Ameliorants Based On Phosphogypsum, Central Kyzylkum Phosphorites And Biohumus, Temur A. Ospanov, Axmed M. Reymov, Rashid K. Kurbaniyazov, Jaxanger M. Bisenbaev Jun 2026

Production Of Organo-Mineral Fertilizing Ameliorants Based On Phosphogypsum, Central Kyzylkum Phosphorites And Biohumus, Temur A. Ospanov, Axmed M. Reymov, Rashid K. Kurbaniyazov, Jaxanger M. Bisenbaev

CHEMISTRY AND CHEMICAL ENGINEERING

Phosphogypsum, a large-scale industrial by-product generated during phosphoric acid production, poses significant environmental challenges due to its accumulation and potential ecological impact. This study investigates the utilization of phosphogypsum as a raw material for producing fertilizing ameliorants in combination with Central Kyzylkum phosphorites and biohumus. Composite mixtures were prepared and granulated using a 30% ammonium sulfate solution as a binding agent. The chemical composition, phase structure (XRD), and microstructure (SEM–EDS) of the obtained materials were analyzed. The results demonstrate the formation of calcium phosphate and sulfate phases, including CaHPO4·2H2O, β-Ca3(PO4)2, and CaSO4·2H2O, which contribute to both fast- and slow-release nutrient …


Processing Of Wc–Co Waste With Selective Extraction Of Co3o4 By Oxidative Fusion In Nano3 Melt, Ilyos A. Bozorov, Aziz B. Ibragimov, Odiljon E. Abdurakhmonov, Mastura Kh. Aripova, Sherzod E. Abdurakhmonov Jun 2026

Processing Of Wc–Co Waste With Selective Extraction Of Co3o4 By Oxidative Fusion In Nano3 Melt, Ilyos A. Bozorov, Aziz B. Ibragimov, Odiljon E. Abdurakhmonov, Mastura Kh. Aripova, Sherzod E. Abdurakhmonov

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study was to develop and experimentally validate a selective method for producing high-purity cobalt oxide from WC–Co hard alloy waste using oxidative fusion in a sodium nitrate (NaNO3) melt, followed by combined aqueous and acidic purification of the solid residue. Cemented carbide scrap and waste containing 6–12 wt.% Co were used as feedstock, without prior grinding. It was found that, during heat treatment in the range of 650–900 °C, tungsten predominantly converts into soluble sodium tungstates, while cobalt concentrates in the solid residue as an oxide phase. Optimal process conditions, such as 850°C and …


Temperature-Dependent Electrocatalytic Activity Of Mxene For Hydrogen Evolution Reaction., Javlonbek I. Mamanazirov, Shavkat I. Mamatkulov Jun 2026

Temperature-Dependent Electrocatalytic Activity Of Mxene For Hydrogen Evolution Reaction., Javlonbek I. Mamanazirov, Shavkat I. Mamatkulov

CHEMISTRY AND CHEMICAL ENGINEERING

This study represents the synthesis technology of MXene catalyst for hydrogen evolution reaction (HER) and investigates the temperature-dependent electrocatalytic activity of MXene-based catalysts in alkaline media. Using a three-electrode configuration in 1M KOH, the electrochemical performance was systematically evaluated across a temperature range of 25 °C to 40 °C. Linear sweep voltammetry (LSV) results demonstrate a significant enhancement in catalytic efficiency at elevated temperatures, evidenced by a consistent shift in polarization curves toward lower potentials. Specifically, the overpotential required to achieve a current density of 10 mA/cmІ decreased from 257 mV at 25 °C to 203 mV at 40°C, marking …


Features Of Formation Of The Structure And Properties Nonfritted Glazes For Sanitary Ceramic Products, Ivan A. Levitskii, Mihail V. Dyadenko, Valery G. Luhin Jun 2026

Features Of Formation Of The Structure And Properties Nonfritted Glazes For Sanitary Ceramic Products, Ivan A. Levitskii, Mihail V. Dyadenko, Valery G. Luhin

CHEMISTRY AND CHEMICAL ENGINEERING

The results of research on the formation of nonfritted glass-ceramic coatings for sanitary ceramic products are presented. The synthesis was carried out in a multicomponent raw material mixture including pegmatite, chalk, quartz sand with a constant content of zirconium silicate, talc, wollastonite, zinc whitewash, refractory clay and kaolin. Glazes were obtained by single firing at a temperature of 1200±5 °C for a duration of 20 hours. Samples of coatings were obtained, the processes of glaze formation were studied, the fusibility of glazes was assessed, and their physico-chemical properties were studied in relation to the features of the formation of the …


Fiber-Optic Products Based On Borosilicate Glasses, Mihail V. Dyadenko Jun 2026

Fiber-Optic Products Based On Borosilicate Glasses, Mihail V. Dyadenko

CHEMISTRY AND CHEMICAL ENGINEERING

The research results of the development of glass compositions for a light-guiding core, reflective and protective coats of optical fiber using a stack method are presented. The optimal ratio of glass-forming oxides and modifications in their compositions has been determined, which ensures the resistance of glasses to crystallization during the manufacture of optical fiber, its thermomechanical strength, the required geometry of optical fibers and the light transmission of fiber-optic products, amounting to 60–75%.

The influence of the chemical composition of the glasses of the light-guiding core and the light-reflecting coats on their refractive index, which determines the magnitude of the …


Synthesis Of Nanostructured Yttrium Oxide Luminescent Powders Activated By Terbium Ions, Eygeniy N. Poddenezhny, Andrei A. Boiko, Olga S. Nevzorova, Ekaterina E. Trusova, Vladimir S. Urbanovich Jun 2026

Synthesis Of Nanostructured Yttrium Oxide Luminescent Powders Activated By Terbium Ions, Eygeniy N. Poddenezhny, Andrei A. Boiko, Olga S. Nevzorova, Ekaterina E. Trusova, Vladimir S. Urbanovich

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work is to synthesize nanostructured luminescent powders of yttrium oxide doped with terbium ions. Y2О3:Tb3+ powders were obtained by thermochemical synthesis (combustion). The sources for the synthesis were nitric acid salts of yttrium and terbium. Organic acids, citric acid and acetic acid, were used as reducing agents and combustible components. It has been established that large porous aggregates with sizes up to 200 microns are formed with citric acid during combustion, and nanostructured finely dispersed powders consisting of nanocrystalline particles with sizes of 39±5 nm are formed with …


Physicochemical Investigation Of Interactions In The Urea – Dl-Alanine System, Suvonkul E. Nurmonov, Saydullo Kh. Azimov Mar 2026

Physicochemical Investigation Of Interactions In The Urea – Dl-Alanine System, Suvonkul E. Nurmonov, Saydullo Kh. Azimov

CHEMISTRY AND CHEMICAL ENGINEERING

A comprehensive physicochemical study of the “urea – DL-alanine – water” system was carried out to determine the nature of the interactions between its components. Methods of isomolar series, X-ray phase analysis, thermal analysis, and FTIR spectroscopy were applied. It was found that molecular associates with a stoichiometry of 1:1 are formed in an aqueous solution, as evidenced by deviations in density, viscosity, refractive index, and electrical conductivity from their additive values. In the solid phase, the system represents a mechanical mixture of the initial components without the formation of new crystalline phases. The presence of hydrogen bonds of the …


Extraction Of Metallic Silver In Powder Form From Electronic Wastes, Mastura Kh. Aripova, Umar A. Yakhyaev, Ripsime V. Mkrtchyan, Shoxrux B. Naimov Mar 2026

Extraction Of Metallic Silver In Powder Form From Electronic Wastes, Mastura Kh. Aripova, Umar A. Yakhyaev, Ripsime V. Mkrtchyan, Shoxrux B. Naimov

CHEMISTRY AND CHEMICAL ENGINEERING

The research is dedicated to the extraction of silver in powder form from electronic wastes and the selective separation of associated elements through the application of hydrometallurgical methods. The conducted study determined the initial chemical composition of the electrical engineering waste (wt.%): Si – 0.08, Al – 0.133, Fe – 0.021, Mg – 0.614, Cu – 0.005,  Zn – 0.02, Ag – 46.9,Zr – 0.557,  Ta – 0.004, Pb – 0.003, Mo – 0.002, S – 0.026. A system for the efficient extraction of metals with minimal losses was developed for the selective dissolution of metals such as Cu, Ni, …


Study Of Microstructural Defects Of Drill Bit Teeth Using Microscopic Methods, Odiljon E. Abdurakhmonov, Mastura Kh. Aripova, Orifjon O. Khomidov, Bakhtiyar T. Zakhidov, Amir I. Abidov Mar 2026

Study Of Microstructural Defects Of Drill Bit Teeth Using Microscopic Methods, Odiljon E. Abdurakhmonov, Mastura Kh. Aripova, Orifjon O. Khomidov, Bakhtiyar T. Zakhidov, Amir I. Abidov

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study is to investigate microstructural defects in drill bit cutting elements, including milled teeth and WC–Co cemented carbide inserts, to clarify their morphology, chemical–phase characteristics, and potential contribution to manufacturing-related defects. To achieve this goal, the study applied a combined approach based on optical microscopy and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS). First, the study examined surface and microstructural features, such as pores, depressions, and local heterogeneities formed during manufacturing. Then, it conducted detailed SEM–EDS analyses of selected local regions, including crack initiation sites. As a result, the study revealed that cutting elements …


Sorption Of Lanthanum(Iii) Ions On Impregnated Solid Extractants, Jaloliddin Q. Abdurashidov, Tadjigul R. Odamova, Maksim A. Kamarou, Zuhra Ch. Kadirova, Shahlo Sh. Daminova Mar 2026

Sorption Of Lanthanum(Iii) Ions On Impregnated Solid Extractants, Jaloliddin Q. Abdurashidov, Tadjigul R. Odamova, Maksim A. Kamarou, Zuhra Ch. Kadirova, Shahlo Sh. Daminova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work was to obtain solid extractants by impregnating the organic reagent 1-phenyl-1,3-butadione (BNA) onto carriers based on styrene-divinylbenzene copolymers (PAD600, PAD400) as well as activated carbon, and to investigate the sorption isotherms of La³⁺ ions under static conditions. The structure of the sorbents before and after La³⁺ ion sorption was studied using SEM-EDX and IR spectroscopy. The parameters of sorption extraction of La³⁺ ions, including extraction degree, sorbent capacity, and distribution coefficient, were evaluated. It was established that the PAD600-BNA sorbent exhibits the most favorable sorption properties toward La3+ ions.


Two-Stage Heat Treatment For Producing Highly Crystalline H-Bn Nanoparticles From Boric Acid And Urea, Sherzod E. Abdurakhmonov, Mastura Kh. Aripova, Umar A. Yakhyaev, Shoxrux B. Naimov, Odiljon E. Abdurakhmonov Mar 2026

Two-Stage Heat Treatment For Producing Highly Crystalline H-Bn Nanoparticles From Boric Acid And Urea, Sherzod E. Abdurakhmonov, Mastura Kh. Aripova, Umar A. Yakhyaev, Shoxrux B. Naimov, Odiljon E. Abdurakhmonov

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of the study was to investigate the formation of the crystal structure of hexagonal boron nitride (h-BN) nanoparticles obtained by the chemical-thermal method using two-stage heat treatment. Boric acid and urea were used as starting precursors, enabling ammonia-free synthesis conditions. It is shown that the first thermal stage at 600 °C under a nitrogen atmosphere leads to the formation of a predominantly amorphous BN-containing precursor, whereas the second stage at 1000 °C in an N2/H2 atmosphere promotes crystallization of a highly ordered hexagonal h-BN phase. The morphology and particle size distribution were examined by transmission …


Structure And Morphology Of Ultradispersed Erbium Ytterbium Oxide Powders Obtained By Deposition Method, Eygeniy N. Poddenezhny, Andrei A. Boiko, Natalya E. Drobyshevskaya, Vladimir S. Urbanovich, Ekaterina E. Trusova Mar 2026

Structure And Morphology Of Ultradispersed Erbium Ytterbium Oxide Powders Obtained By Deposition Method, Eygeniy N. Poddenezhny, Andrei A. Boiko, Natalya E. Drobyshevskaya, Vladimir S. Urbanovich, Ekaterina E. Trusova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of research is to develop a new method for synthesis of ultra-dispersed crystalline powders of lanthanide oxides, in particular, erbium oxide doped with ytterbium oxide, intended for making transparent ceramics. The formation of nanostructured powders of the erbium oxide – ytterbium oxide system using deposition and heat treatment processes by co-deposition of salt solutions mixed with ammonium carbonate and hydrogen peroxide complex solution at temperature of 10 °C followed annealing at 100, 650, 900 and 1200°C was studied. Studies of the morphological and structural characteristics of the powders using scanning electron microscopy and X-ray phase analysis showed that …


Production Of Recombinant Β-Galactosidase Protein In Bombyx Mori (Bmn1) Baculovirus Insect Cells, Shuhrat Sh. Khasanov, Jumanazar Ch Mengturayev, Jaloliddin M. Abdurakhmanov, Dilmurodjon B. Turdaliyev, Shakhnoz S. Azimova Dec 2025

Production Of Recombinant Β-Galactosidase Protein In Bombyx Mori (Bmn1) Baculovirus Insect Cells, Shuhrat Sh. Khasanov, Jumanazar Ch Mengturayev, Jaloliddin M. Abdurakhmanov, Dilmurodjon B. Turdaliyev, Shakhnoz S. Azimova

CHEMISTRY AND CHEMICAL ENGINEERING

In this study we aimed to obtain a novel recombinant β-galactosidase baculovirus using the Bombyx mori baculovirus – insect cell expression system. A new recombinant plasmid was constructed on the basis of the pBacPAK8 transfer vector and cloned in E. coli cells. Subsequently, a recombinant baculovirus was generated in Bombyx mori cells, and efficient expression of the β-galactosidase gene was observed. The enzymatic activity of the protein was confirmed by the ONPG assay. The results demonstrated that the baculovirus – insect cell system expands the possibilities for producing proteins of industrial significance.


Photocatalytic Activity Of The Mixed Of Ti/Fe/Mo Oxide Composites For Degradation Of Nitrofurazone, Dilshoda R. Tursunova, Zuhra Ch. Kadirova, Shahlo Sh. Daminova, Kadriya Kh. Gabidullina Dec 2025

Photocatalytic Activity Of The Mixed Of Ti/Fe/Mo Oxide Composites For Degradation Of Nitrofurazone, Dilshoda R. Tursunova, Zuhra Ch. Kadirova, Shahlo Sh. Daminova, Kadriya Kh. Gabidullina

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of study is synthesize mixed oxide composites based on titanium dioxide, iron and molybdenum oxides from industrial waste materials and evaluated for their photocatalytic degradation performance of nitrofurazone—a persistent and toxic antibiotic frequently detected in aquatic environments. Various Ti/Mo ratios (T95M5, T87.5M12.5, T75M25, and T50M50) were prepared through thermal treatment at 600 °C and characterized using XRD, UV–Vis and Raman spectroscopy to assess structural and optical properties.XRD and Raman analyses confirmed the presence of anatase-phase TiO₂ and Mo/Fe oxides, with optimal crystallinity and heterojunction formation observed in the T87.5M12.5 composite. UV–Vis spectroscopic studies demonstrated that this composite exhibited …


Gas Chromatographic Analysis Of Fractions Separated By Atmospheric Distillation Of Pyrolysis Distillate, Gulnora K. Komolova, Lola A. Yusupova Dec 2025

Gas Chromatographic Analysis Of Fractions Separated By Atmospheric Distillation Of Pyrolysis Distillate, Gulnora K. Komolova, Lola A. Yusupova

CHEMISTRY AND CHEMICAL ENGINEERING

The primary objective of this study is to optimize the process of isolating the C9 hydrocarbon fraction from pyrolysis distillate and to evaluate the impact of various temperature regimes on the product composition. To achieve this goal, the dry distillation process was conducted at three different temperatures: 152 °C, 159 °C, and 170 °C. Condensate samples obtained from each test were analyzed using gas chromatography (GC). The analysis results revealed that the fraction obtained at 152 °C yielded the most favorable outcome: the C9 fraction yield was 11.11%, which is higher than the values obtained at 159 °C (4.59%) and …


Lightweight Thermal Insulation Brick Based On Jerdanak Clay Shale, Obtained With The Addition Of Sawdust, Mastura Kh. Aripova, Sarvar T. Bozorov Dec 2025

Lightweight Thermal Insulation Brick Based On Jerdanak Clay Shale, Obtained With The Addition Of Sawdust, Mastura Kh. Aripova, Sarvar T. Bozorov

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study was to produce lightweight thermal insulation bricks based on Djerdanak clay shale with the addition of wood sawdust. The starting materials were clay shale from the Djerdanak deposit, fireclay made from it, and wood chips—a waste product from the wood processing industry. The optimal brick composition was determined to include 60% clay shale, 40% fireclay made from clay shale, and 14% wood chips (over 100%). The apparent density of the optimal brick composition corresponds to an apparent product density of 1 g/cm³ and a compressive strength of 3.6 N/mm². The microstructure of the material demonstrates …


Waste Utilization Considering Volatiles Circulation Behavior In Cement Kilns, Geun-Seong Lee, Farrukh B. Erkinov, Zebo A. Babakhanova, Mukhammadamin Sh. Jololdinov, Mastura Kh. Aripova Dec 2025

Waste Utilization Considering Volatiles Circulation Behavior In Cement Kilns, Geun-Seong Lee, Farrukh B. Erkinov, Zebo A. Babakhanova, Mukhammadamin Sh. Jololdinov, Mastura Kh. Aripova

CHEMISTRY AND CHEMICAL ENGINEERING

Since the cement kiln process has various advantages for waste incineration, the waste utilization as alternative fuel has been widely applied in the cement process. For waste utilization in kiln process, it is necessary to operate within the range of not-affecting the clinker quality and the operation stability, and not-causing pollution problems, with ensuring the smooth clinker production. In order to quantitatively analyze the volatiles circulation phenomena during waste utilization as alternative fuel in the kiln process, the simplified volatiles circulation model is derived based on material balances of volatiles, from which the permissible waste utilization % as alternative fuel …


Physico-Chemical Study Of Interaction In The “Urea – Glycine – Water” System, Suvonkul E. Nurmonov, Saydullo Kh. Azimov Dec 2025

Physico-Chemical Study Of Interaction In The “Urea – Glycine – Water” System, Suvonkul E. Nurmonov, Saydullo Kh. Azimov

CHEMISTRY AND CHEMICAL ENGINEERING

A comprehensive physicochemical study of the aqueous “urea – glycine” system was conducted to establish the mechanisms of intermolecular interaction and stability parameters for the development of modified liquid nitrogen fertilizers (LNF). Isomolar series, visual-polythermal analysis, X-ray phase analysis (XRD), single-crystal X-ray diffraction (SC-XRD), IR spectroscopy, and thermal analysis (DTA/TGA) methods were applied. It was found that the interaction of components in solution leads to the formation of molecular associates stabilized by hydrogen bonds. The XRD and SC-XRD methods confirmed that no new individual chemical compounds are formed in the solid phase. It was proven that the addition of glycine …


Unlocking The Industrial Potential Of Khojaykon Sylvinite Through Mineralogical And Chemical Investigations, Elyor D. Eminov, Kholtura Ch. Mirzakulov, Gavkhar E. Melikulova, Ruslan Ch. Yorbobaev, Kamola S. Arifdjanova Dec 2025

Unlocking The Industrial Potential Of Khojaykon Sylvinite Through Mineralogical And Chemical Investigations, Elyor D. Eminov, Kholtura Ch. Mirzakulov, Gavkhar E. Melikulova, Ruslan Ch. Yorbobaev, Kamola S. Arifdjanova

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this study is to analyze the chemical, mineralogical, and fractional composition of sylvinite from the Khodjaikan deposit in Uzbekistan in order to assess its potential for potassium fertilizer production. Using chemical analysis, XRD, and IR spectroscopy, the ore was found to contain KCl (19.5–30.1%), NaCl (62.08–71.85%), CaCl₂ (1.12–1.32%), and MgCl₂ (0.18–0.32%). The water-insoluble residue, mainly sulfates, carbonates, and silicates, was also identified. These findings are important for improving beneficiation processes and reducing waste. Comparison with the Verkhnekamsk deposit highlights the quality and potential of Khodjaikan sylvinite. The research supports sustainable resource management.


Changes In The Structure And Properties Of Titanium In The Process Of Pressure Treatment, Sardor S. Abriev, Nasiba U. Abduraimova, Zokir R. Akramov, Yulbarskhon N. Mansurov Dec 2025

Changes In The Structure And Properties Of Titanium In The Process Of Pressure Treatment, Sardor S. Abriev, Nasiba U. Abduraimova, Zokir R. Akramov, Yulbarskhon N. Mansurov

CHEMISTRY AND CHEMICAL ENGINEERING

Titanium is classified as a critical metal. It serves as a raw material for a wide range of industries owing to its unique properties – high strength at low density, corrosion resistance, and biocompatibility makes it indispensable. Uzbekistan and China possess primary resources for titanium production. However, the complexity of extraction and particularly processing, combined with high production costs, limits its large-scale use and increases the risk of shortages in industrial manufacturing. In this study, the structural and property evolution of titanium during pressure-based processing was investigated. Technology for producing powder titanium by metal forming methods is proposed. The results …


The Structure And Properties Of Er2o3 And Yb2o3 Based Ceramic Materials, Sintered Under High Pressure, Vladimir S. Urbanovich, Vadim D. Zhivulko, Eygeniy N. Poddenezhny, Ekaterina E. Trusova, Vladimir S. Niss Dec 2025

The Structure And Properties Of Er2o3 And Yb2o3 Based Ceramic Materials, Sintered Under High Pressure, Vladimir S. Urbanovich, Vadim D. Zhivulko, Eygeniy N. Poddenezhny, Ekaterina E. Trusova, Vladimir S. Niss

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the work was to obtain high-density optically transparent ceramic samples by sintering cubic modification Er2O3 and Yb2O3 oxides micropowders at the pressure of 7 GPa and the heating current power of 0.6–1.0 kW, which was demonstrated. Non-monotonic dependence of the density on the heating current power has been established. The maximum density values of 9.2 g/cm3 (Er2O3) and 9.8 g/cm3 (Yb2O3) were achieved at the power of 0.8 and 0.9 kW, respectively. During sintering, the cubic phase partially transforms into the …


Transformations Of Uzbekistan Quartz Raw Materials – Quartzites Of The Dzherdanak Deposit And Vein Quartz Of The Nurota Deposit Under Thermal Impact, Umar G. Nomazov, Mastura Kh. Aripova Aug 2025

Transformations Of Uzbekistan Quartz Raw Materials – Quartzites Of The Dzherdanak Deposit And Vein Quartz Of The Nurota Deposit Under Thermal Impact, Umar G. Nomazov, Mastura Kh. Aripova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the work is to study the transformations of quartz raw materials as a result of high-temperature exposure. The objects of the study were quartzite from the Dzherdanak deposit in the Surkhandarya region and vein quartz from the Nurota deposit in the Samarkand region. The mineralogical composition of natural raw materials and phase and structural transformations during high-temperature exposure to 1430 ° C were studied using X-ray and differential thermal analysis. Based on the results of physicochemical analysis methods, it was found that vein quartz consists entirely of quartz and, therefore, it can be assumed that impurity elements …


Kinetics Of Adsorption Of Copper And Nickel Ions Using A Rice Husk-Based Sorbent, Aziza A. Maksudova, Shukhrat A. Mutalov, Klara M. Adilova Aug 2025

Kinetics Of Adsorption Of Copper And Nickel Ions Using A Rice Husk-Based Sorbent, Aziza A. Maksudova, Shukhrat A. Mutalov, Klara M. Adilova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study is to investigate the adsorption kinetics of Cu(II) and Ni(II) ions from aqueous solutions using an adsorbent obtained by treating rice husk with a solution of monoethanolamine. The experiments evaluated the influence of contact time on the efficiency of metal ion removal and calculated the adsorption capacity. To analyze the adsorption process kinetics, pseudo-first-order and pseudo-second-order kinetic models were applied. The results demonstrated that the adsorption process follows the pseudo-second-order kinetic model. Thus, monoethanolamine-modified rice husk can be considered an effective, environmentally friendly, and economically viable sorbent for the removal of heavy metal ions from …


Quantum-Chemical Study Of Complex Compounds Of Lanthanides With 2-Aminobenzimidazole Derivatives, Bakhtigul Yu. Ruzieva, Feruza F. Fayzullayeva, Zuhra Ch. Kadirova, Shahlo Sh. Daminova Aug 2025

Quantum-Chemical Study Of Complex Compounds Of Lanthanides With 2-Aminobenzimidazole Derivatives, Bakhtigul Yu. Ruzieva, Feruza F. Fayzullayeva, Zuhra Ch. Kadirova, Shahlo Sh. Daminova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study is to perform quantum-chemical modeling of mixed-ligand complexes of trivalent lanthanoid ions (Ln³⁺) involving primary ligands — 2-amino-1-methylbenzimidazole (MAB) and 2-phenylmethyl-1H-benzimidazole (FAB), as well as additional ligands — diethyldithiocarbamate (DEDTK), benzohydroxamic acid (BGK), and potassium diisopropyldithiophosphate (DiPDTP). Quantum-chemical calculations were carried out using semi-empirical methods within the PM3 and PM6 approaches, implemented in the BIOVIA Materials Studio (Accelrys Studio 2017) software package. The obtained data made it possible to determine the influence of the nature of the mixed ligands on the coordination behavior of lanthanoids and the stability of the corresponding complexes.


Synthesis And Ir Spectroscopic Study Of Complexes Of Selected 3d-Metals With 2-(Phenylmethyl)-1h-Benzimidazole, Gulnoza O. Babayeva, Gulbeka G. Mamatova, Daminbek A. Ziyatov, Lola Sh. Makhmudova, Shahlo Sh. Daminova Aug 2025

Synthesis And Ir Spectroscopic Study Of Complexes Of Selected 3d-Metals With 2-(Phenylmethyl)-1h-Benzimidazole, Gulnoza O. Babayeva, Gulbeka G. Mamatova, Daminbek A. Ziyatov, Lola Sh. Makhmudova, Shahlo Sh. Daminova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study was the synthesis and structural investigation of coordination compounds of selected 3d-metals with 2-(phenylmethyl)-1H-benzimidazole (FAB) using IR spectroscopy. Complexes of copper(II), nickel(II), cobalt(II), and zinc(II) with the general formula [M(FAB)2Cl2], as well as a complex [Co(FAB)2(ac)2], were synthesized. IR spectroscopic analysis revealed that FAB coordinates to metal ions through the nitrogen atom of the benzimidazole ring. Shifts in the ν(C=N), ν(C-N) bands and the appearance of new bands in the 580-430 cm⁻¹ region corresponding to ν(M-N) and ν(M-Cl) confirm the formation of metal complexes. It was established …


Technological And Mechanical Properties Of Polyethylene Filled With Nano-Sized Calcium Carbonate, Ilyos M. Makhmudov, Ravshan I. Adilov, Muzafar G. Alimukhamedov, Farangiz B. Izzatullayeva Aug 2025

Technological And Mechanical Properties Of Polyethylene Filled With Nano-Sized Calcium Carbonate, Ilyos M. Makhmudov, Ravshan I. Adilov, Muzafar G. Alimukhamedov, Farangiz B. Izzatullayeva

CHEMISTRY AND CHEMICAL ENGINEERING

Currently, one of the most effective and cost-effective ways to modify the properties of polyethylene is to introduce various fillers of organic or inorganic origin. The purpose of this work was to study the effect of the concentration of nanosized calcium carbonate on the technological and physicomechanical properties of polyethylenes of various origins. In the work, we used two grades of polyethylene: HDPE (273-83) and LDPE (10803-020) produced by Kazanorgsintez OJSC. The following were used as nanofillers: nanosized calcium carbonate in the form of a compound of the Nano-cal NC-K0117 brand made in China. The dependence of the physicomechanical properties …


Additional Loss On Ignition Of Cement Raw Mixes At High Temperatures, Geun-Seong Lee, Farrukh B. Erkinov, Mastura Kh. Aripova Aug 2025

Additional Loss On Ignition Of Cement Raw Mixes At High Temperatures, Geun-Seong Lee, Farrukh B. Erkinov, Mastura Kh. Aripova

CHEMISTRY AND CHEMICAL ENGINEERING

Loss on ignition (LOI) of cement, raw materials and raw mixes in cement industry is specified as the weight loss at 900~1000 oC and 15~30 minutes in the standards of each region (GOST, ISO, ASTM, JIS, KS) in the world, and the clinker yield produced from the raw mixes feeding to the kiln process is generally derived from the LOI. The kiln conditions are significantly different from those specified in the standards, because the material temperature is up to 1450 oC and the residence time is about 15 minutes above 1000 oC in the kiln burning process. …


Composition Of Porcelain Mass Based On Clay Shale From The Dzherdanak Deposit, Ripsime V. Mkrtchyan Aug 2025

Composition Of Porcelain Mass Based On Clay Shale From The Dzherdanak Deposit, Ripsime V. Mkrtchyan

CHEMISTRY AND CHEMICAL ENGINEERING

Known sources of high-quality raw materials are depleted. To meet the growing demand for porcelain products, natural raw materials from new deposits are being studied. The aim of the study is to develop a composition of porcelain mass for household porcelain based on unconventional raw materials - clay shales of the Dzherdanak deposit. Compositions of hard porcelain based on clay shales and other components of local natural raw materials with and without magnesium oxide have been developed. As a result of X-ray and electron microscopic studies of the porcelain structure, it was determined that the crystalline phases in the porcelain …