Gulnara Kokayeva

Prof. Gulnara Kokayeva

orcid

Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
27 February 2023 in Applied Sciences
Verified
Journal Article
Open access
PDF file
МММайгуль Мурсалыкова
Майгуль Мурсалыкова
MKMukhtarbek Kakimov
Mukhtarbek Kakimov
AKAmirzhan Kassenov
Amirzhan Kassenov
BIBauyrzhan Iskakov
Bauyrzhan Iskakov
ZSZhadra Sergibayeva
Zhadra Sergibayeva
ASAnuarbek Suychinov
Anuarbek Suychinov
This article is devoted to modeling the pressing process of an experimental screw press for safflower oil production in small enterprises of the grain processing industry. The theoretical analysis for developing the process of oil pressing in a screw press is considered. Using methods of mathematical modeling, the problem of squeezing the liquid phase from dispersed material is described and solved. The basic scheme and characteristics of the press equipment and the principle of its work are presented. The proposed method of the theoretical calculation of the pressing process helps to determine the optimal parameters and to press safflower oil using the proposed design of the screw press. During the process of pressing, the highest value of oil yield is reached at the diaphragm gap of δ = 0.1 mm and screw rotation speed of ω = 6.2 rad/s.

17 June 2024 in Foods
Verified
Journal Article
Open access
PDF file
МКМухтарбек Какимов
Мухтарбек Какимов
MMMaigul Mursalykova
Maigul Mursalykova
Bożena GajdzikBożena Gajdzik
Bożena Gajdzik
Radoslaw WolniakRadoslaw Wolniak
Radoslaw Wolniak
GKGulnara Kokayeva
Gulnara Kokayeva
Michał BembenekMichał Bembenek
Michał Bembenek
This study aims to improve press equipment for safflower oil production by using a mechanism that optimizes pressure distribution within screw turns. A detailed analysis of the main components of the produced safflower oil was performed, encompassing both quantitative and qualitative assessments. Through the exploration of dependencies governing the safflower oil pressing process on the screw press, the optimal parameters were determined. As a result of the research, the optimal diaphragm gap between the gape cylinder and the pressing screw was determined, with the optimal oil yield percentage achieved at ω = 6.2 rad/s and δ = 5 mm. The study also compared the performance of the existing Dream Modern ODM-01 screw press and its upgraded version by analyzing the extracted oil. The results reveal changes in the quantitative and qualitative composition of the main oil components following the operation of the existing and the modernized screw presses. For instance, the amount of unsaturated fatty acids, such as oleic acid (7.7 ± 0.566%), linoleic acid (85.3 ± 1.185%), and linolenic acid (1.2 ± 0.223%), increased. There was an increase in the presence of inorganic substances in safflower oil: iron (0.023 ± 0.031 mg/kg), phosphorus (0.086 ± 0.059 mg/kg), silicium (0.136 ± 0.075 mg/kg), and others. The findings of this study hold significant commercial value and offer promising prospects for global market implementation.

25 September 2021 in Kompleksnoe Ispolzovanie Mineralnogo Syra = Complex Use of Mineral Resources
Verified
Journal Article
Closed access
MSM.A. Serekpayeva
M.A. Serekpayeva
GKGulnara Kokayeva
Gulnara Kokayeva
RNRimma Niyazbekova
Rimma Niyazbekova
SKS. Kardybai
S. Kardybai
The outcomes of studying epoxy-based composite materials supplemented with microsilica are provided in the article. Microsilica was used as a filler. The samples were produced on the epoxy ED-20 basis supplemented with 2, 5 and 10 mas. % of microsilica. The structure and size of finely dispersed filler particles were defined. The obtained composites were tested for resistance to the effect of variable temperatures, corrosive, and abrasion. The study outcomes proved that samples supplemented with 2% of microsilica are more resistant to acid and alkali as well as to petrol than those ones supplemented with 25% of microsilica. Besides the amount of the filler from 2 to 10% doesn’t sufficiently affect the resistance to variable temperatures. When microsilica is added to epoxy resin, it causes scuff resistance increase. The conducted testing proved that the developed composite materials are resistant to the effect of variable temperatures, corrosive, and abrasion. This enables to use these materials as coatings and anti-corrosion protection during machine maintenance.

5 March 2025 in Designs
Verified
Journal Article
Open access
PDF file
KSKaribek Tagaevich Sherov
Karibek Tagaevich Sherov
ASAlmat Sagitov
Almat Sagitov
GTGulim Tusupbekova
Gulim Tusupbekova
ASAibek Sherov
Aibek Sherov
GKGulnara Kokayeva
Gulnara Kokayeva
NKNurgul Karsakova
Nurgul Karsakova
The problem of increasing the tool durability (service life) when machining hard-to-machine materials is one of the major practical problems of modern mechanical engineering. This paper aims to improve the wear resistance of modular disk mills using the pre-processing method. Second-order rotatable planning was applied for the experimental study of the pre-processing of modular disk mills. Experimental research on the pre-processing of modular disk mills was carried out on a vertical milling machine XH950A when milling a workpiece made of steel 45. It was revealed that the increase in pre-processing modes up to specific values (f = 60 mm/min; vc = 17 m/min; t = 6 min) on the tool durability period has a positive effect. At the same time, the tool durability period was increased up to T = 155 min. Tests of the machined modular disk mills were carried out in the conditions of the laboratory base to determine the durability period. After pre-processing at different modes, each modular disk mill was used to machine the workpiece until wear signs appeared on the cutting edge. At the same time, the time was recorded to determine the durability period. It was found that the optimum mode of tool preliminary pre-processing provides the best deformation and thermal conditions for hardening the tool cutting part. As a result of modeling with the ANSYS 2024 R1 program, it was found that a hardened layer is indeed formed on the cutting part of the modular disk mill after pre-processing. The results obtained show the possibility of using the preliminary pre-processing method to improve the wear resistance of other metal-cutting tools.

30 April 2025 in Foods
Verified
Journal Article
Open access
PDF file
MMMaigul Mursalykova
Maigul Mursalykova
GKGulnara Kokayeva
Gulnara Kokayeva
МКМухтарбек Какимов
Мухтарбек Какимов
Bożena GajdzikBożena Gajdzik
Bożena Gajdzik
Radoslaw WolniakRadoslaw Wolniak
Radoslaw Wolniak
Michał BembenekMichał Bembenek
Michał Bembenek
This study presents an innovative, resource-efficient apparatus for safflower oil production, designed for small- and medium-sized enterprises. The developed equipment integrates grinding and pressing into a single operation, optimizing extraction efficiency while reducing operational costs and processing time. A comparative analysis of the physicochemical and fatty acid profiles of safflower oil produced using traditional and combined grinding-pressing methods confirmed the superiority of the new approach. Optimal process parameters were identified: pressing time (τ = 3.41 min) and degree of grinding (i = 0.25), which resulted in higher oil yield and improved product quality. Multiple regression and sensitivity analyses revealed that temperature is the most significant factor positively influencing oil yield, whereas excessive grinding intensity and pressure negatively impact extraction efficiency. The results of the multiple regression analysis demonstrated that pressing time had a statistically significant impact on oil yield (p < 0.05). Although temperature was identified as the most influential factor overall, the significance of pressing time indicates that this variable also contributes meaningfully to the extraction efficiency. The regression model revealed a nonlinear (quadratic) relationship between pressing time and oil yield, suggesting that there is an optimal pressing duration. Beyond this optimal point, further increases in pressing time may result in a decline in yield due to over-compression or the release of undesired compounds. Interestingly, pressing time was found to have no significant effect on oil yield, suggesting that optimizing temperature and pressure is more critical for enhancing efficiency. The developed apparatus not only enhances oil quality, particularly its fatty acid composition, but also offers a scalable, sustainable solution for improving safflower oil production. These findings highlight the feasibility of integrating grinding and pressing, paving the way for advancements in cost-effective, high-yield oil extraction technologies.

31 August 2023 in Eastern-European Journal of Enterprise Technologies
Verified
Journal Article
Open access
PDF file
GKGulnara Kokayeva
Gulnara Kokayeva
RNRimma Niyazbekova
Rimma Niyazbekova
MSMira Serekpayeva
Mira Serekpayeva
AIAinur Ibzhanova
Ainur Ibzhanova
ABAmirbek Bekeshev
Amirbek Bekeshev
Utilization of industrial waste and secondary raw materials, in particular, in the production of metallic silicon and silicon-containing alloys, which include silica vapors (microsilica), is the main task of implementing environmental policy and solves the problem of their storage and negative impact on the environment, in order to reuse them in polymer composites. The use of microsilica as a filler in composite materials based on epoxy resins contributes to a positive effect on the basic properties of the resin, and also makes it possible to use the composite material as coatings and parts in the repair of machinery and equipment. The aim of the work was to establish the positive effect of microsilica as a filler in composite materials based on ED-20 epoxy resin on improving the physical and mechanical properties of composite materials. Within the framework of this work, studies were conducted to test composite materials based on ED-20 epoxy resin, differing in different filler content of 2, 5, 10, 15 wt. % on impact strength, tensile strength and modulus of elasticity, adhesion and impact strength of the coating. The analysis of the obtained results showed a positive effect of microsilica as a filler in composite materials based on ED-20 epoxy resin on the physical and mechanical properties of the composite material. The optimal filler content was determined, which is 2 % of the mass of the ED-20 epoxy resin, while an increase in adhesion, toughness of the composite material by 45 %, tensile strength and modulus of elasticity by 21 % and 5 %, respectively, and the strength of the coating on impact by 32 %, compared with the addition of microsilica in ED-20, which shows the prospects of using microsilica as a filler in composite materials