Second-order Regression Equation Research Articles

Optimization of green spherical agglomeration process based on response surface methodology for preparation of high-performance spherical particles

Spherical agglomeration (SA) is a processing technique that enhances the physical properties of particles, reduces the number of unit operations in pharmaceutical manufacturing, and improves process efficiency. However, one of the limitations of SA is its high nonlinearity, which makes scalability a challenge. This prospective study was designed to realize the optimization of SA process parameters of aspirin, the world’s first and most widely used nonsteroidal anti-inflammatory drug, by developing a green SA model through response surface methodology. First, Plackett-Burman experiments were conducted to identify the key operating variables affecting SA, and Sustainability Index (STI) was defined to evaluate the effects of these operating variables on the SA and the energy input to the environment during the post-processing process. Furthermore, the effects of three independent variables on mean size, yield, and STI were investigated based on Box-Behnken design. A second-order regression equation with response values was developed to optimize the above three objectives. As a result, the spherical products were obtained with excellent powder properties, including anti-caking property, filtration property, and tableting performance compared to the raw materials. This work provides an experimental and modelling basis for the further application of this environmentally-friendly SA technology.

ОБОСНОВАНИЕ ИСПОЛЬЗОВАНИЯ БИОМОДИФИЦИРОВАННОЙ СОИ В ПРОИЗВОДСТВЕ ПРОДУКЦИИ НИЗКОГЛИКЕМИЧЕСКОГО ДЕЙСТВИЯ

The objective of the study is to substantiate and develop the technology of soybean-mineral concentrate (SMC) and soybean-mineral paste (SMP) based on biomodified soybeans for the use of SMC and SMP in the formulations of low-glycemic products. Objectives: to study the dynamics of accumulation of chelated ions of mineral substances in the process of biomodification of soybeans in a vanadium minera¬lized aqueous medium, to determine the chemical composition of the obtained SMC. The objects of the study are soybean seeds of zoned varieties Oktyabr-70, Lydia, SMC. To determine the chemical composition of the developed SMC, standard methods for studying food products were used, corresponding to the normative and technical documentation valid in the Russian Federation. Determination of mineral substances was carried out by mass spectrometry in inductively coupled argon plasma on an ICP-MS ELAN DRC II device by Perkin Elmer (USA). Construction of mathematical models in the form of second-order regression equations and their analysis were carried out using the Appol program and the Pareto-optimal solution method (KPS program). The paper indicates the features of diabetes mellitus development based on modern research, substantiates the possibility of using chelated vanadium as an ingredient in the production of hypoglycemic food products. A number of literary sources indicating the oxidative and hypoglycemic ability of vanadium compounds are analyzed. The paper presents the results of a study of soybean seed biomodification in a vanadium mineralized aqueous medium and the accumulation of minerals by endoproteinases of germinating soybean seeds. As a result, a two-fold increase in chelated mineral elements is noted: Na1+, Ca2+, K1+, Mg2+, V4+. A technology has been developed for the production of soybean-mineral concentrate (SMC) and soybean-mineral paste (SMP) for the subsequent use of these ingredients in the formulation of low-glycemic products. The chemical composition of the SMC is represent¬ted by proteins 40 %, fats – 20, carbohydrates – 10, water – 6 %.

Analysis of rock grinding results in centrifugal-vibrational disintegrating module

This scientific study is devoted to analysis of the results of grinding materials such as marble, sandstone and granite in a disintegrating module. This module combines grinding of particles in the countercurrent centrifugal mill with simultaneous vibrational screening of the finished product. The essence of the study is that two-factor experiments have been carried out according to the full factor scheme. Here, the achieved degree of crushing is used as the response function. The valuable factors have the initial size and the ultimate strength of the material. As a result of two-factor analysis of variance, it has been found that the compressive strength and the initial size of the material, regardless of the sieve vibration amplitude, have a significant and comparable scale effect on the material crushing ratio. At the same time, the interaction of factors has no statistical significance. Also, approximation of experimental data by the first- and the second-order regression equations has been performed. For simplified calculations, it is recommended to use the linear regression equation, while for more accurate ones, the second-order equation is more suitable.

Решение задач тепло- и массообмена в технических объектах на основе компьютерного моделирования

The purpose of the work is to carry out the necessary theoretical research and practical research for the possibility of using modern methods of ventilation of premises or using these methods in various technical installations of a nuclear reactor. The study is based on the study of the aerodynamic characteristics of an object (a crowded ship room or a nuclear reactor) at reference points. The scientific novelty of the work consists in the use of patented technologies (originally proposed by the author, and then patented by the responsible executor of the topic, a hydroaerodynamic transformer) and equipment for solving these problems for use in nuclear energy. The results of scientific research may be of interest to a wide range of specialists and scientists, mainly for nuclear energy. The research methods are based on the methods of similarity theory (Reynolds similarity criterion) and differential equations. A mathematical approach to modeling the system under study and heat and mass transfer processes occurring in an industrial nuclear power plant or spatial objects of ship premises has been formed. A general methodological approach and a scheme for the research installation of a nuclear reactor have been developed, and a model based on second-order regression equations has been constructed. Based on mathematical models and confirmed theoretical results, the distribution of gas-liquid flows is empirically visualized in experimental studies. The intensification of heat and mass transfer in the fuel assembly of a nuclear reactor is considered.

Improving the work process efficiency of a tillage module for pre-sowing tillage

The formation of a differentiated structure of the arable horizon during the pre-sowing processing of the grant is a relevant task that can be solved by designing appropriate soil-processing technical means. A scientific hypothesis has been put forward, according to which increasing the efficiency of the process of forming a differentiated structure of the arable horizon can be achieved by improving the design and substantiating the structural and technological parameters of the tillage module for pre-sowing tillage. Numerical simulation was carried out in the Simcenter STAR-CCM+ software package using the Lagrangian multiphase model employing the discrete element method. Calculation of second-order regression equations and statistical processing of the obtained data was carried out in the Wolfram Cloud software package. As a result of the simulation of the improved design of the tillage module, which includes one drum, plowshare, casing, and cleaner, it was found that it performs the operation of separation and redistribution of soil aggregates with almost the same efficiency as the basic design with 2 drums and plowshare. As a result of the simulation of the work process of the improved tillage module, regression equations of the content of the 10–30 mm fraction in the 0–4 cm soil layer and the content of the 0–10 mm fraction in the 4–8 cm soil layer from the research factors were obtained. The chosen factors of influence were a casing outlet clearance, casing inlet clearance angle, cleaner inclination angle, drum rotation frequency, unit movement speed, and processing depth. Solving the problem of multi-criteria optimization, the rational structural and technological parameters of the tillage module for pre-sowing tillage were calculated

SIMULATION OF THE PROCESS OF FORMING THE EDGE AND MIXING THE COMPONENTS OF THE COMPOST MIXTURE WITH A SINGLE-DRAMED AERATOR

The most widespread approach for implementing the technological process of organic compost production involves using mobile aerator-mixers of the rotary-drum type. Based on the analysis of various designs of mechanized composting equipment from previous theoretical and experimental studies conducted by renowned scientists, as well as our own research, it has been established that mechanized compost production requires further investigation. The analysis revealed that rotary drum-blade working elements are efficient. However, there is insufficient research on the dependencies of changes in the height of the pile during formation, indicators of homogeneity and structure of the mixture, energy consumption during the operation of drum-blade working elements in relation to the rotation frequency, working element's linear velocity, and geometric parameters of the blades. Additionally, changes in the bulk density, mixture structure, and temperature distribution within the pile under the influence of the working elements have not been investigated. This highlights the relevance of conducting research in the chosen direction. The analysis of developed models for the interaction of the working element with the compost mixture has shown that they cannot be used to assess the quality of mixing and pile formation, as it is necessary to consider the movement of discrete particles that make up the compost mixture. The mathematical description of the movement of discrete elements is achievable using modern CAE (Computer-Aided Engineering) systems, and one such system is Simcenter Star-CCM+. Through numerical simulation of the technological process of pile formation and mixture mixing, an argumentation of the constructive and technological parameters of the working element of a single-drum aerator was conducted. To construct the physical-mathematical model of the compost mixing and pile formation processes, the following mesh and physical models were utilized: meshless DEM (Discrete Element Method), solution interpolation, Lagrangian multiphase, unsteady implicit, DEM, multiphase interaction, gravity force, and boundary forces of DEM. As a result of simulating the compost mixture mixing process using a single-drum blade working element, dependencies of the height (H') and width (L') of the formed pile on the rotation frequency (n), linear velocity of the working element (V), and the blade's inclination angle (ξ) were established. A mathematical expression in the form of second-order regression equations was derived, linking the coefficient of variation of mixing quality (δ) with the research factors. Solving the compromise problem using the Wolfram Cloud software package allowed us to determine the rational parameters for the working element: rotation frequency (n) of 237 rpm, linear velocity (V) of 0.15 m/s, and blade inclination angle (ξ) of 15.8°. Consequently, the coefficient of variation of mixing quality (δ) was found to be 0.51, and the width (L') and height (H') of the formed pile were 1.23 m and 1.54 m, respectively.

Numerical Simulation and Experiment on Pill Coating of Red Clover Seeds under the Action of Vibrating Force Field

In order to solve the problem of the low qualification rate of the pilling and coating of small-grain forage seeds, a vibration force field is introduced to the traditional vertical disk coating machine to promote the mixing of materials and improve the qualification rate of the pilling. Using the typical small-grain forage seed red clover as an example, we used the vibration force field after adding seed powder particles to a coating pot for the theoretical analysis of the force situation, using the discrete element software EDEM to construct a red clover seed simulation model with the coefficient of discretization as the evaluation index. We studied the effects of the rotational speed of the coating pot, the vibration frequency of the pot, the amplitude of the vibration of the pot, and the other operating parameters of the pot on the uniformity of the seed powder mixing, with the pelletization of the pass rate as the physical evaluation standard, using a one-way test to study the effect of operating parameters on the pelletization pass rate. We used the qualified rate as the physical evaluation standard, through a single-factor test, to study the influence of the working parameters on the qualification rate of the pilling. The results show that the simulation test evaluation index of the discrete coefficient and the physical test evaluation index of the pilling qualification rate with the change rule of the working parameters is consistent with the discrete coefficient, and can be used as an indirect evaluation index of the quality of pilling. To further determine the optimal combination of working parameters, a quadratic regression orthogonal design test was conducted with the discrete coefficients as the evaluation index, and the second-order regression equations of the red clover seeds were established and analyzed by ANOVA using Design-Expert software. The study shows that, when the rotational speed of the coating pot is 307.204 rpm, the vibration frequency is 2.526 Hz, and the vibration amplitude of the coating pot is 5.843 mm, the predicted coefficient of dispersion at this time is 8.1%. Simulation using the best combination of parameters to obtain the average value of the dispersion coefficient of 8.4%, relative to the predicted value of 3.7%, indicated that the optimization of the experimental regression model is accurate, and the results obtained for the vibration of small seeds under the conditions of the design of the pellet granulation coating machine and the optimization of the pelletization coating process parameters have a certain degree of reference significance.

European Green Deal: The Impact of the Level of Renewable Energy Source and Gross Domestic Product per Capita on Energy Import Dependency

The level of renewable energy use and economic development of a country, as separate indicators, have an influence on the level of energy resource imports, but the mutual impact of renewable energy sources and gross national product on the growth or decrease of energy imports dependency have not been studied. Therefore, the aim of this study was to evaluate the energy security of European countries by taking into account the consumption of renewable energy sources and the economic development of the countries. In particular, the article examines the relationship between energy import dependency, gross domestic product (per capita), and renewable energy sources in 27 countries in the European Union. Regression analysis of data on EU countries for 11 years (from 2011 to 2021) was used to determine the non-linear influence of gross domestic product and renewable energy use on energy import dependency. This influence was simulated by a second-order regression equation. The analysis of the equation for extremes made it possible to conclude that with a share of energy from renewable sources at the level of 32%, the economic development of a country does not require an increase in energy import dependency, and with larger values of energy from renewable sources, a decrease in energy import dependency may occur. In addition, according to the analysis of the obtained mathematical dependence, it is recommended that countries with a gross domestic product of up to 10,000 euros per capita use renewable energy sources at the level of 40%. For the countries with a domestic product of up to 30,000 euros per capita should use renewable sources at the level of 50%. For countries with a gross domestic product of more than 30,000 euros per capita, renewable energy sources at a level of more than 55% is recommended. A high level of renewable energy use will allow a country to increase its gross domestic product without a significant increase in energy import dependency, and at the level of renewable energy sources of more than 32%, an increase in gross domestic product does not actually lead to an increase in energy import dependency. An increase in the use of renewable energy sources above 40% of the total consumption of energy resources in a specific country, in particular, and in the European Union, in general, will ensure an increase in energy security and an increase in the level of energy independence.

Calibration of Ramie Stalk Contact Parameters Based on the Discrete Element Method

To obtain the physical parameters and contact parameters of ramie stalk decorticating simulation, the structural dimensions, density, moisture content, elastic modulus, and contact parameters of the ramie stalk were measured in this study based on the phloem and xylem of the ramie stalk. The physical stacking angles of the phloem and xylem were measured by the cylinder lift method and the extraction of the partition method, respectively. The contact parameters between the xylem and phloem of the ramie stalk were directly calibrated. Additionally, the contact parameters of the phloem–phloem, phloem–Q235A steel, xylem–xylem, and xylem–Q235A steel were used as calibration objects, and the simulated stacking angle was used as the evaluation index. Then, the Plackett–Burman test was designed to screen for the parameters which were significantly affecting the simulated stacking angle. Furthermore, the steepest ascent test determined the optimal range of values for two significant parameters of the phloem and three significant parameters of the xylem. Based on the central composite design, the second-order regression equations between the significant parameters of the phloem and xylem and the stacking angle were established, respectively. The physical stacking angles of 37.93° for phloem and 27.17° for xylem were the target values to obtain the optimal parameter group. The results showed that the restitution, static, and rolling friction coefficients between the xylem and phloem were 0.60, 0.53, and 0.021, respectively. The static and rolling friction coefficients between the phloem and phloem were 0.41 and 0.056, respectively. The rolling friction coefficient between the xylem and Q235A steel was 0.033, and the static and rolling friction coefficients between the xylem and xylem were 0.44 and 0.016, respectively. The verification test showed that the relative error values were less than 2.11%, which further indicated that the modeling method and parameter calibration of the ramie stalk phloem and xylem models were accurate and reliable. They can be used for the subsequent calibration simulation tests of ramie stalk bonding parameters and ramie stalk decorticating simulations.

Microwave-assisted extraction optimization and conventional extraction of phenolic compounds from coriander leaves: UHPLC characterization and antioxidant activity

Background: Qualitative and quantitative investigations of bioactive compounds in plant materials are heavily based on the selection of an accurate extraction method. Aims: That’s why; this work consists of a comparative study between Microwave Assisted Extraction (MAE) and Conventional Extraction (CE), based on the total phenolic compounds (TPC) yield, phenolic profile, and antioxidant activity of coriander leaves powder (Coriandrum sativum L.). Material and Methods: MAE was optimized and performed using the Response Surface Methodology (RSM), and was modeled by using a second-order regression equation. While CE was done using the classic water bath method. Results: Under the optimal conditions, the recovery of TPC yield obtained was 37.94 ± 2.06 mg (MAE) vs 44.47 ± 0.57 mg GAE/g DW (CE). The UHPLC characterization showed a close phenolic composition of the two extracts, mainly represented by quercetin glucosides and by dimethoxycinnamoyl hexoside. No significant difference (p>0.05) was recorded in terms of the antioxidant activity of both extracts, as estimated by Ferric reducing antioxidant power (FRAP), Nitric oxide (NO•), and superoxide anion (O2•-) scavenging tests. Conclusions: Hence, the exploitation of MAE has many valuable advantages, as the processing time is brief and the antioxidant activities and phenolic composition were not affected by the extraction process.

A Calibration Method for the Resolution of 2D TPP Laser Direct Writing.

To improve the fabrication efficiency of the two-photon polymerization (TPP) laser direct writing, the TPP exposure process was set to complete by a single-line scan, which was named 2D TPP. The voxel of the 2D TPP should be large enough to cross the photoresist and the underlayer. To explore the resolution limit of the 2D TPP considering the thickness of the photoresist, a new method named the 45° scanning method was proposed. Meanwhile, a two-photon micro-nano fabrication platform was developed. A group of experiments based on the orthogonal decomposition method was carried out to analyze the width and length of the voxel on the S1805 photoresist under different laser power and processing speed. To confirm whether the resolution of the micro-nano structures fabricated by 2D TPP is consistent with the width of the voxel, aluminum wire grids were fabricated through the 2D TPP and the metal lift-off process. A second-order regression equation of the machining resolution and input parameters of the 2D TPP is deduced. The correlation coefficient between the width of the voxel and the aluminum wire grids is 0.961, which means a significant positive correlation between them. Finally, the second-order regression model derived from the fabrication resolution of the 2D TPP was validated by experiments. Full 2D grids were fabricated using 2D TPP and mental lift-off process. This paper provides a convenient, low-cost, and high-efficiency method for calibrating the fabrication resolution of 2D TPP on various photoresists.

Optimization of Process Variables for Prediction of Penetration Depth of HSLA Steel Welds Using Response Surface Methodology

The statistical model is created for predicting penetration depth in an alternating current-based additional axial magnetic field controlled shielded metal arc welding of ASTM A 516 Gr.70 steel. The design for the trials is developed using the Placket-Burman design and response surface methodology. The created model determines the optimum process variables for getting excellent penetration depth. The input variables (current, magnetic field density, and magnetic frequency) are chosen for a response like penetration depth. This model can predict the main effects and the interacting effects of three process variables. The findings reveal that a higher current value with a low magnetic field density leads to deeper penetration and vice versa. Furthermore, a greater penetration depth is achieved at lower magnetic field density and higher magnetic frequency. With a desirability of 98.8%, the optimum process variables are 110 A, 0 mT, and 60 Hz. The predicted response values produced from the regression equation based upon process variables are extremely similar to the observed output, demonstrating the usefulness of second-order regression equations. For improved joint efficiency, a high level of penetration is needed.

OPTIMISATION OF TECHNOLOGICAL PARAMETERS OF FERMENTATION OF HIGHLY CONCENTRATED WORT FROM GRAIN RAW MATERIALS FOR BIOETHANOL PRODUCTION

Bioethanol is one of the most promising alternatives to fossil fuels and can be produced from various renewable sources rich in carbohydrates. A priority direction of biotechnological research is the development of new resource-saving technologies of bioethanol production. For effective bioconversion of carbohydrate-containing raw materials into bioethanol, it is advisable to optimise the technological parameters of fermenting highly concentrated wort obtained from grain raw materials. Laboratory experimental studies of the samples according to the newly developed technology have helped to substuntiate the technological parameters of fermenting highly concentrated wort and establishing the regular patterns in how the ethanol concentration in fermented washes changes depending on the initial concentration of dry matter in the wort, the industrial yeast concentration, and the fermentation temperature. Grain wort was fermented with the osmophilic thermotolerant race of distiller’s yeast Saccharomyces cerevisiae DО–16 (IMB Y-5099) at 32–37°C. The initial concentration of dry matter was 26–30%. To optimise the technological parameters of the process of fermenting highly concentrated grain wort, an experiment was designed, which resulted in building mathematical models. To obtain the second-order regression equations in natural form, the basic level of each technological parameter of the process and its variability interval were determined. The mathematical model developed makes it possible to calculate the ethanol concentration depending on the initial concentration of the wort, the concentration of industrial yeast, and the fermentation temperature. Fermentation of highly concentrated wort for bioethanol production was optimised according to the equations of the mathematical model. It has been established that to synthesise the maximum alcohol concentration in washes using the highly concentrated wort fermentation technology, the wort concentration should be 30% of dry matter, the concentration of industrial yeast 40 million/cm³, and the temperature of the main fermentation 35°C.

Discrete Element Simulation Modeling Method and Parameters Calibration of Sugarcane Leaves

Objective The construction method of the discrete element model and the setting of simulation parameters in the strip- and blade-shaped sugarcane leaf are unclear. The simulation model’s accuracy greatly influences the dynamic response characteristics between particles, and it is necessary to improve the accuracy of simulation parameters through parameter calibration. Method The discrete element parameters are optimized and calibrated based on the response surface methodology (RSM) with sugarcane leaf physical angle of repose as the response value. Firstly, the basic physical parameters and angle of repose of sugarcane leaves were measured by physical tests, and the simulation model of sugarcane leaf was established by the multi-sphere polymerization model and XML method. The effects of the sugarcane leaf model filled with different radii particles on the simulation angle of repose and simulation efficiency were analyzed to find the optimal filling particle size of the sugarcane leaf model. Then, a Plackett-Burman test was used to select the parameters that significantly influence the simulation angle of repose. Furthermore, the optimal value ranges of the three significant parameters were determined by a steepest ascent search test, and the second-order regression equation between the significant parameters and angle of repose was established based on the Box-Behnken test, the optimal combination of parameters was obtained with the physical angle of repose of 21.15° as the optimal target value. Finally, a gas-solid coupling simulation test was conducted with the trash content as the test index and compared with the field test. Result The optimal filling particle size of the sugarcane leaf simulation model was 2 mm. The optimal combination of significant parameters was as follows: the static and rolling friction coefficients between sugarcane leaves were 0.21 and 0.05, respectively, and the static friction coefficient between sugarcane leaves and steel was 0.30. There was no significant difference between the simulation value and the test value of trash content, and the maximum relative error between them was 8%, which further showed that the parameter calibration of the sugarcane leaf model was reliable. Conclusions The results showed that the modeling method and parameter calibration of the sugarcane leaf model was accurate and reliable and could be used for subsequent gas-solid coupling simulation research, as well as providing a reference for the calibration of the discrete element parameters of the strip-and blade-shape materials.

Material removal mechanisms, processing characteristics and surface analysis of Cf-ZrB2-SiC in micro-EDM

Cf-ZrB2-SiC is a new composite material with excellent properties for making the next-generation aerospace component. This material is extremely difficult to removal by mechanical machining, and there is a lack of research on feasible secondary processing methods of this composite at present. Micro-EDM is not limited by material hardness, so it is very suitable for machining this material. In this paper, the Material removal mechanisms and processing characteristics of Cf-ZrB2-SiC by micro-EDM is analyzed. The removal mechanism of composite materials is explored though the discharge crater morphology, and the single-discharge experiments of each phase materials with different medium and different energies are also carried out as a reference. Electrical discharge milling experiments of Cf-ZrB2-SiC are performed to explore the medium on processing index, and found that the best surface quality and maximum processing efficiency can be realized in kerosene. An experiment with four factors (pulse width, voltage, peak current, capacitance) and three indexes (surface roughness, MRR, TWR) is designed to analyze the Cf-ZrB2-SiC process characteristics of micro-EDM and the response surface diagram and second-order regression equation are obtained. Milling the Cf-ZrB2-SiC by electrical discharge according to the optimal combination of surface roughness parameters deduced above, the as-machined surface is analyzed including the surface morphology by SEM, element content by EDS and the surface phase by XRD. The feasibility and advantages of micro-EDM on machining Cf-ZrB2-SiC are prove.

Improving Energy Efficiency of Grain Cleaning Technology

The relevance of the research topic was substantiated, and the purpose and objectives of the study were formulated. It was determined that the energy efficiency of the grain cleaning process can be evaluated only when all the machines operate in a single production line and are coordinated in productivity. Research on energy savings and energy efficiency in the technological process of post-harvest grain treatment using grain cleaning units by implementing the method of mathematical experiment planning (MEP) was conducted. The method is based on transforming the initial mathematical models of various research objects into a model in the form of regression equations convenient for solving the problems of research, analysis and optimization of the object. For the first time, the mathematical description of the target function was performed by conducting a multifactorial experiment based on second-order design. The research produced adequate second-order regression equations, making it possible to determine the minimum specific consumption of electricity for the technological process of post-harvest grain treatment at grain cleaning facilities, while complying with the agrotechnical requirements for the quality of the cleaned grain. The problem of optimization of the research object was solved by mathematical transformations, which enabled obtaining graphical and analytical interpretations of the optimum area. For this purpose, the canonical transformation of the mathematical model and the method of two-dimensional cross-sections of the response surface were used. Research has led to the development of scientifically based standards of specific electricity consumption for grain cleaning processing schemes, which serve as criteria for evaluating energy savings in the technological processes.

RESULTS OF NUMERICAL MODELLING OF THE PROCESS OF SEPARATION OF SEED MATERIAL OF SMALL-SEEDED CROPS ON A CYLINDRICAL CELL TRIER

The relevance of this study is conditioned upon the need to increase the amount of high-quality seed material of small-seeded crops, which cannot be achieved without an important process of separation. The separation is based on technical and technological principles of separation of seed material, depending on the differences in physical and mechanical properties of individual components of seed material. Cylindrical triers are used to separate seeds according to their length. The purpose of the study was to find the theoretical regularities of changes in the technological parameters of separation of the seed material of small-seeded crops from the structural and mode parameters of a cylindrical seed trier by numerical modelling. The solution of the set problems was implemented in the STAR-CCM+ programme based on the finite element method. Considering the physical and mechanical properties of the seed material, as a result of the study, a visualisation of the separation process was obtained depending on the research factors: the rotation frequency of the trier cylinder, the diameter of the cylinder, and the number of seeds and impurities in the seed mixture. According to the simulation results, the dependence of the relative content of impurities ε on factors under study was obtained in the form of second-order regression equations. Using the Mathematica programme, a compromise problem was solved, which lies in minimising the multiplicative function of the research criteria, and the rational constructive and technological parameters of the trier separator were found. The material of this paper is intended for scientists, graduate students, designers of agricultural machinery, students, and specialists in agricultural production.

Parameter Measurement of Edible Sunflower Exudates and Calibration of Discrete Element Simulation Parameters

To improve the accuracy of the parameters used in discrete element simulation tests in the process of clearing fresh sunflowers, this study took the extracts of fresh sunflower as the research object and used a combination of physical experiments and simulation experiments to calibrate the discrete element simulation parameters. First, the composition of the edible sunflower extract is determined, and then, the physical test method is used to determine the characteristics of the edible sunflower extract material. Based on the results of the physical test as a simulation basis, the Plackett–Burman test is used to screen the significance of the test parameters, and the screening results show that the shear modulus, static friction coefficient, and collision recovery coefficient of sunflower kernels have significant effects on the simulated angle of repose. On the basis of the steepest climbing test, the Box–Behnken test is carried out to obtain the simulated angle of repose and significance. The second-order regression equation of texture parameters is optimized with the actual physical angle of repose (24.68°) as the target value to obtain the optimal parameter combination. Finally, through the two-sample T test, p > 0.05 is obtained, indicating that the simulated angle of repose and the actual physical test angle of repose are not significantly different, and the relative error is 0.923%, which verifies the reliability of the optimal simulation parameter combination. The research results show that the calibrated simulation parameter combination can be used in discrete element simulation tests of the extraction process of sunflower extracts.

Microwave-assisted extraction of antioxidant compounds from Russian olive leaves and flowers: Optimization, HPLC characterization and comparison with other methods

Russian olive is a medicinal plant containing phytochemicals with antioxidant activities, which are of great interest due to their beneficial health effects. Our preliminary studies produced extracts from Russian olive leaves and flowers and determined their potential antioxidant activity and their most abundant phenolic compounds were detected. However, the maximum retention of these antioxidant compounds during microwave-assisted extraction (MAE) requires optimized process conditions. Therefore, two-level fractional factorial designs in preliminary tests were used for assessing the magnitude of microwave extraction factors' effects on the extraction of bioactive compounds from Russian olive samples and the experimental domains were determined. Subsequently, Response surface methodology (RSM) was conducted to determine the optimized MAE process variables including citric acid’s molarity (X1: 1–5 M), extraction temperature (X2: 60–110 °C), ethanol concentration (X3: 0–100%) and solid to solvent ratio (X4: 5–15) for maximum recovery of total phenolic content, total flavonoid content and total antioxidant compounds in the extracts. Based on the results, the optimal extraction conditions were as follows: solid to solvent ratio of 7.5 (w/v), citric acid molarity of 2 M, ethanol concentration of 59.8% and 66.4%, and temperature of 97.4 °C and 97.5 °C for Russian olive leaves and flowers, respectively. In addition, the influence of extraction parameters on the responses was modeled using a second-order regression equation and a good agreement between the predicted values and the experimentally obtained values was indicated. Finally, among phenolic compounds which were previously identified through Quadrupole Time of Flight Mass Spectrometer (QTOF-MS) analysis, three abundant flavonoids of the extracts with therapeutic properties including isorhamnetin, luteolin and rutin contained in the optimized extract from MAE were compared with that of ultrasonic extraction and conventional extraction using high-performance liquid chromatography (HPLC) analysis. Results confirmed MAE as an efficient method for extraction of bioactive phytochemicals from Russian olive.

Predicting the ultimate tensile strength and wear rate of aluminium hybrid surface composites fabricated via friction stir processing using computational methods

In the present study, aluminium hybrid surface composites were prepared by incorporating boron carbide (B4C) and Aluminium oxide (Al2O3) ceramic particles via the Friction Stir Processing (FSP) route. Tool rotational speed, Tool traverse speed, Axial force, and Reinforcement ratio were the chosen process parameters. Response Surface Method (RSM) based Central Composite Design (CCD) was used to conduct the experimental trials. A second-order regression equation was developed for the responses, ultimate tensile strength (UTS), and wear rate (WR). Statistical tests were performed to check the adequacy of the regression models. The effect of process parameters on the responses was studied. It was found that tool traverse speed was the most dominant process parameter, followed by tool rotational speed, axial force, and reinforcement ratio. The optimal process parameters for the responses were found using a genetic algorithm, where the regression equations from RSM were used as the objective function.