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In this study based on the accelerated over relaxation (AOR) method we make an iterative scheme for solving generalized Lyapunov matrix equation$$ {A}{X}+{X}{B}+\sum_{j=1}^{m}{N}_j{X}{M}_j={C},$$over complex or real matrices. Then we analyze the convergence of the new iterative method in detail. There have been discussions for the calculation of optimal parameters. Finally a numerical example is given to demonstrate the capability of the new method.

In this study based on the accelerated over relaxation (AOR) method we make an iterative scheme for solving generalized Lyapunov matrix equation ... over complex or real matrices. Then we analyze the convergence of the new iterative method in detail. There have been discussions for the calculation of optimal parameters. Finally a numerical example is given to demonstrate the capability of the new method. [ABSTRACT FROM AUTHOR]

A new cable-damper stopper equipped for Coal-Fired Thermal Power Plants (CFTPPs) was proposed in our previous paper, where a series of shaking table tests were carried out to investigate its seismic performance, so this paper aims to reveal the working mechanism of the stopper from the theoretical and numerical simulation aspects. The stopper is composed of three main components, i.e. a steel cable, a steel block and a viscous damper. First, the nonlinear restraint stiffness of the steel cable to the boiler was derived; second, the critical damping of the stopper, which makes the vibration of the boiler decay exponentially with no oscillation, was derived; third, an iterative method was proposed to globally tune the CFTPP structure, which makes it possible to obtain the optimal parameters of the cable-damper stopper, including the diameter of the steel cable and damping coefficient of the damper. Finally, finite element models were built and time history analyses were conducted to verify the proposed optimization approach. Firstly, the finite element models were proved valid through the comparison between the results of the simulations and the experiments. Then, based on the results of the simulations, the theoretical procedure was validated. The results revealed that the proposed cable-damper stopper reduced the seismic responses of displacements of the top floor and the boiler significantly, about 30.18% and 60.01% respectively compared with their counterparts of CFTPPs without stoppers. [ABSTRACT FROM AUTHOR]

In this paper, we extend SMSNS [Pourbagher M, Salkuyeh DK. On the solution of a class of complex symmetric linear systems. Appl Math Lett. 2018;76:14–20.] iteration method for solving a class of complex symmetric system of linear equations. We propose a successive-overrelaxation (SOR) acceleration scheme for SMSNS (SMSNSSOR), discuss the convergence conditions of it and give the optimal parameters which make the fast convergence. Numerical results demonstrate that SMSNSSOR iteration method is feasible and effective for solving complex symmetric systems, and performs better than some other usually used iteration methods. [ABSTRACT FROM AUTHOR]

Purpose: This work developed an idea and systematically explains 'equal modal frequency and damping' (EMFD) technique to derive the complete closed form solutions of tuned mass damper (TMD), to reduce dynamic response of structural system. Method: The optimum parameters for the damped system till date required numerical search technique or shootout technique, which is the trial-error method, of-course add complexity in selecting parameter obtained at optimality conditions. The study of optimum parameter based on EMFD shows the complete closed-form solution, independent to another optimum parameter. Result: The parameters solely depend on structural damping and mass ratio. The study reveals the multiple optimal solutions. This work investigates the various optimal parameters under harmonic excitation, also compare same with relevant researchers. To confirm its robustness under random excitation various real earthquake time history loads are applied to investigate behavior of different solutions. A demonstration of the shear building for harmonic and random excitation for various solutions provides valuable practical insights for the research endeavors. Conclusion: Furthermore, the article presents a novel method for finding optimal parameters efficiently without requiring numerical calculations at any stages. The significance of multiple optimal solutions becomes evident when structural systems face random excitation. [ABSTRACT FROM AUTHOR]

This study aims to identify optimal parameters for using Thulium fiber lasers (TFL) in ureteral stone lithotripsy to ensure laser safety and maximize efficacy. Our goal is to improve the outcomes of single-use semi-rigid ureteroscopy for treating stones located in the proximal ureter. A clinically relevant thermal testing device was designed to investigate heating effects during TFL stone fragmentation. The device was utilized to identify safe power thresholds for TFL at various irrigation rates. Three other devices were used to assess varying pulse energy effects on stone fragmentation efficiency, dusting, retropulsion, and depth of tissue vaporization. Comparative experiments in fresh porcine renal units were performed to validate the efficacy and safety of optimal TFL parameters for semi-rigid ureteroscopy in proximal ureteral stone procedures. Our study found that the improved device generated a higher thermal effect. Furthermore, the safe power threshold for laser lithotripsy increased as the irrigation rate was raised. At an irrigation rate of 40 ml/min, it is safe to use an average power of less than 30 watts. Although increasing pulse energy has a progressively lower effect on fragmentation and dust removal efficiency, it did lead to a linear increase in stone displacement and tissue vaporization depth. Thermal testing showed 20 W (53.87 ± 2.67 °C) indicating potential urothelial damage. In our study of laser lithotripsy for proximal ureteral stones, the group treated with 0.3 J pulses had several advantages compared to the 0.8 J group: Fewer large fragments (> 4 mm): 0 vs. 1.67 fragments (1-2.25), p = 0.002, a lower number of collateral tissue injuries: 0.50 (0-1.25) vs. 2.67 (2–4), p = 0.011, and lower stone retropulsion grading: 0.83 (0.75-1) vs. 1.67 (1–2), p = 0.046. There was no significant difference in operating time between the groups (443.33 ± 78.30 s vs. 463.17 ± 75.15 s, p = 0.664). These findings suggest that TFL irradiation generates a greater thermal effect compared to non-irradiated stones. Furthermore, the thermal effect during laser lithotripsy is influenced by both power and irrigation flow rate. Our study suggests that using a power below 15 W with an irrigation flow rate of 20 ml/min is safe. Moreover, a pulse energy of 0.3 J appears to be optimal for achieving the best overall stone fragmentation effect. [ABSTRACT FROM AUTHOR]

Blisks subjected to rough machining for channel creation must undergo finishing processes, and such processes must achieve the required tolerance limits. A high-quality surface finish and predictable long tool life are critical for the finish milling of blisks. Accordingly, the aim of this study was to optimize parameters for the finish machining of an Inconel 718 alloy monolithic blisk. Ball-cone mills were used to machine the blade surface at a constant depth. A sensory tool holder was used to collect cutting force signals during machining, and a digital microscope was used to examine tool wear. The surface texture measuring instrument was used to measure blisk blade surface roughness to evaluate processing quality. This study manipulated two cutting parameters, namely cutting speed and feed per tooth, and investigated their effects. The relationship between cutting conditions and machining efficiency was analyzed. According to the experimental results, we identified a set of optimal parameters at effective cutting speeds of 46.53 m/min, feed per tooth of 0.1 mm/tooth, and depth of cut of 0.05 mm for marginal tool wear and fast cutting speeds. Then the corresponding tool life was estimated by using the derived parameters. [ABSTRACT FROM AUTHOR]

In this paper, a simple preconditioner with two parameters (SPTP) is introduced for solving a class of saddle-point problems. The SPTP preconditioner is block upper triangular and does not contain the approximate matrix of the Schur complement matrix. Theoretical analyses on the sufficient conditions under which the SPTP iterative sequence converges to the unique solution, are given in detail. Convergence conditions in some special cases are also analyzed. Moreover, detailed analyses on the theoretical optimal parameters and corresponding optimal convergence factor of the SPTP method are given. Some numerical examples show that the SPTP iterative method outperforms several SOR-type methods by using theoretical optimal parameters simultaneously. Some newly proposed methods are also compared with the SPTP iterative method by using the experimental optimal parameters simultaneously, and the SPTP iterative method is still advantageous, from the point of view of iteration step and CPU time. Moreover, we also investigate relatively practical values of the parameters since searching for the optimal parameters will waste a lot of time in practice. [ABSTRACT FROM AUTHOR]

The present work is devoted to studying the effect of temperature on the formation of a submicron-sized particles of lead sulfide (PbS). Lead sulfide samples were obtained by chemical bath deposition method. 25 ml of an aqueous solution of lead nitrate Pb(NO3)2, 75 ml of sodium hydroxide NaOH and 50 ml of thiourea CH4N2S with molar concentrations of 0.18 M (1.52 g), 0.38 M (1.151 g) and 0.11 M (0.397 g), respectively, were used as reagents. In the process of obtaining samples, solutions of lead nitrate and sodium hydroxide were initially mixed at temperatures of 70℃ and 100℃, then a thiourea solution was added to this mixture. It was found that temperature has an effect on the formation of PbS structures. It is shown that at a temperature of 100℃ isolated particles are formed, whereas at a temperature of 70℃ a film is formed. The morphology and elemental composition of the obtained lead sulfide (PbS) samples were studied by scanning electron microscopy (SEM) and the surface structure was studied using an atomic force microscope (AFM). As a result of the study of the morphology and texture of the surface of lead sulfide samples, the average size of isolated particles was determined, which is ~144 nm, and these particles also had a cubic shape with a smooth surface. [ABSTRACT FROM AUTHOR]

In order to reduce the labor intensity and improve the efficiency of pruning, this study designed a multi-section luffing apple pruning equipment suitable for apple orchards in hilly and mountainous areas of China. In the essay, the structure and working principle of the equipment are expounded, the cutter was analyzed, and the parameters were determined. Using the self-made test bench to simulate the field experiment, this study selected the ratio of cutting speed to feeding speed and feeding speed as the influencing factors and took the cut-off rate, cutting efficiency and cutting power as the objectives to carry out single factor experiment and quadratic regression orthogonal experiment. The test results show that the cutting power increases with the increase of ratio of cutting speed to feeding speed, and the cut-off rate and cutting efficiency first increase and then decrease. As the feeding speed increases, the cutting efficiency and power increase, and the cut-off rate decreases. When the cutoff rate was greater than 80%, the optimal combination of operating parameters was the feeding speed of 0.55 m/s and ratio of cutting speed to feeding speed of 1.29. Under this combination, the cut-off rate was 84.9%, the cutting efficiency was 13.1, and the cutting power was 175.7 W. The error between the predicted target value of the model and the average measured target value was less than 7%, so the test results are reliable. According to the obtained optimal operating parameters, the actual cutting experiment of the pruning equipment in the field was carried out, and the cutting rate was 96.3%, which meet the design requirements. This study can also meet the needs of mechanized pruning of fruit trees with different crown shapes, improve the applicability of pruning equipment, and provide support for the development of mechanized pruning equipment in China. [ABSTRACT FROM AUTHOR]

The purpose of this study was to apply infrared-assisted spouted bed drying (IRSBD) technology for Areca taro drying and to investigate the effects of different parameters on its drying quality. Specifically, in order to determine the suitable conditions for IRSBD, the effects of different drying temperatures (45 °C, 50 °C, 55 °C, and 60 °C) and cutting sizes (6 × 6 × 6 mm, 8 × 8 × 8 mm, 10 × 10 × 10 mm, and 12 × 12 × 12 mm) on the drying characteristics, temperature uniformity, and quality properties (including colour, rehydration ratio, total phenol content, total flavonoid content, and antioxidant activity) of Areca taro were studied. The results showed that the optimal drying condition was the sample with a cutting size of 10 × 10 × 10 mm and drying at 50 °C, which yielded the dried sample with the best colour, highest total phenol and flavonoid contents, maximum antioxidant capacity, and rehydration ratio. [ABSTRACT FROM AUTHOR]

This study proposes a ventilation and dust control approach using doubleforced air pipes at the tunnel excavation face, aiming to optimize the dust control and reduction measures for underground coal mining environment. We designed a physical model in proportion to the 11,139 excavation face in the Zhangji Coal Mine of China Huaihe Energy Holding Group Coal Company. To begin with, CFD numerical simulation was employed to unveil the basic laws of the double-forced air pipe ventilation approach, including airflow characteristics and dust concentrations. The orthogonal experimental method was then adopted to analyze the influence mechanism of installation location and airflow ratio of the double pipes on the dust density around the driver’s operating space. Results suggest that the double-forced air pipe ventilation can efficiently improve the airflow velocity at the excavation face, reaching 5.54 m/s. With the minimum dust density around the driver’s operating space as the optimal parameter standard and combined with the R value, the three factors in the orthogonal experiment can be sorted as: the distance between the forced ventilation pipe at the driver’s side and the excavation face (R = 206.91) > the distance between the forced ventilation pipe at the return air side and the excavation face (R = 171.72) > the airflow ratio of the two pipes (R = 77.52). The optimal combination is that the distance between the ventilation pipe at the driver’s side and the excavation face is 5 m, the distance between the ventilation pipe at the return air side and the excavation face is 5 m, and the airflow ratio of the two pipes is 6:4. In such a case, the dust density around the driver’s operating space is 48.21 mg/m3, achieving an ideal dust control effect. [ABSTRACT FROM AUTHOR]

The effect of the donor impurity concentration and the lifetime of charge carriers in a crystalline silicon substrate on the maximum power of heterojunction thin-film solar cells is studied. The model used in the calculations takes into account the features of photocurrent generation under conditions of medium or high levels of injection of charge carriers at an arbitrary ratio between the diffusion length and the thickness of the semiconductor wafer. The proposed technique makes it possible, with sufficient accuracy for practical purposes, to calculate the permissible variation limits of the substrate parameters, which ensure the specified values of the performance characteristics of photoelectric converters. [ABSTRACT FROM AUTHOR]

Studies were conducted in 2020–2021 to evaluate the relationship between fertility parameters of typical chernozem soils and winter wheat yields and identify their optimal values for the studied crop in Kursk oblast. The objects of research were typical heavy loamy chernozem soils and the Leonida winter wheat variety. Information–logical analysis made it possible to identify in the soil–plant system the nature, direction, and strength of the relationship between parameters defining the humus and agrochemical state of the soil and winter wheat yields. In 2020, yield strongly correlated with mobile phosphorus content in the soil and the ratio between mobile humic acids (MHA) and humus: the information transfer efficiency coefficients (Ce) reached 0.23 and 0.22, respectively. Also, yield depended on the following parameters: the ratio between microbial biomass (MB) and MHA (Ce = 0.19), exchangeable calcium content (Ce = 0.18), and ratio of MB to mobile humic substances (MHS) (Ce = 0.17). Under dry conditions of 2021, at low soil fertility levels and with the same agricultural technology, the role of the following parameters in the formation of yields by the Leonida winter wheat variety increased: MB proportion in MHA (Ce = 0.31), MB proportion in humus (Ce = 0.28), humus content in the soil (Ce = 0.20), and MHS quality (Ce = 0.19). The optimal fertility parameters of a typical chernozem soil that made it possible to form a winter wheat yield of 5.58–7.47 t/ha under the conditions of sufficient moisture supply in spring and semiarid July were as follows: humus content = 5.0–5.1%, pHaq. 5.9–6.0, mobile phosphorus content = 83–119 mg/kg soil, mobile potassium content = 103–121 mg/kg, MHA/H ratio = 5.9–6.5, MB/MHA = 34.0–40.5, MB/MHS = 13.2–16.5, Ca/Mg = 4.2–4.4, MHS/H—11.0–12.0, MHA/MFA = 0.93–1.00, MHS carbon content = 5100–5500 mg/kg soil, MHA carbon content = 2920–3200 mg/kg, and MB carbon content = 860–990 mg/kg. A lower soil fertility level (humus content = 4.90–5.05%, MHA/H = 4.8–5.3, MB/MHA = 33.8–40.5, MB/MHS = 14–17, MHA/MFA = 0.93–1.00, and MB carbon content = 510–800 mg/kg soil) and dry weather conditions reduced the yield of the Leonida winter wheat variety to 3.34–5.28 t/ha. [ABSTRACT FROM AUTHOR]

Using a tuned mass damper (TMD) is one of the passive methods of controlling structural vibrations. This energy absorption system has a mass, a spring, and a damper attaching to the main structure and vibrating with it, reducing the dynamic response of the structure by preventing the intensification. Therefore, finding optimal parameters is one of the main essential issues in the study and design of tuned mass dampers. This study investigates the optimization of parameters of an adjusted mass damper to reduce the displacement and relative response of a multi-story structural system equipped with this damper. For this purpose, a 10-story frame with similar properties on each floor and a 10-story frame with different properties on each floor were modeled under seismic loading in OpenSees software. The optimum parameters were extracted by Matlab software, using the particle swarm optimization (PSO) algorithm, whale optimization algorithm (WOA), and the combination of these two algorithms (Hybrid PSO-WOA) and state space equations controlled the results. Comparing the results with the methods presented by other researchers showed that the proposed methods have good performance and are recommended as approximate and rapid methods for the optimal design of these dampers.

ABSTRACTExopolysaccharides (EPSs) are highly heterogeneous natural polymers, can exhibit some unique bio-logical activities, such as anti-oxidation, inflammation regulation, anticancer and anti-viral activities, etc. A new type of EPS was obtained from the fermentation supernatant of Lactiplantibacillus plantarum YT013. However, the low yield of EPS posed a challenge for further research and application. Therefore, in this study, the production process of EPS was optimized, and anti-cancer cells proliferation activity was investigated. Identified the best single-factor conditions for EPS production, including initial pH 6, inoculation amount 5% (v/v), temperature 37°C, cultivation time 36 h, glucose 3% (w/v), soy peptone 1.5% (w/v), KH2PO4 0.3% (w/v). Under these conditions, the maximum production of EPS reached 0.630 mg/mL, which is 1.31 times higher than that before optimization. Concurrently, the nonlinear model was used for fitting, and it was found that the Voigt nonlinear model was in better agreement with the optimization results, which can be used as an effective tool for optimizing EPS production conditions. Furthermore, the anti-proliferative activity of EPS was evaluated using the human gastric cancer AGS cell line in vitro. MTT assay revealed a strong inhibitory effect of EPS on AGS cell proliferation. Additionally, flow cytometry analysis indicated that EPS promoted apoptosis in AGS cells. Lactiplantibacillus plantarum YT013 EPS, as a biodegradable and nontoxic natural active substance, shows potential as a natural antitumor substance.

Given the high technical requirements for cleaning root crop heads from residues, the development of new, more advanced cleaners is an important and urgent issue. The research aims to improve the quality of the cleaning process by determining the optimal kinematic, structural, and operational parameters of a new root crop head cleaner from root residues. A new design of the root crop head cleaner was created, which allowed the use of cleaning elements with different mechanical properties and sizes, and changing its kinematic parameters depending on the crop it processes. A new experimental setup was also made to install this cleaner and change its operational parameters. A new mathematical model of a multifactorial experiment was developed for the study. Based on the results of the field experimental study, correlation analysis, and statistical numerical calculations using a computer, the optimal design, kinematic, and operational parameters of the improved cleaner were determined, at which the highest quality of cleaning (the lowest amount of stover residues per linear metre) is observed. Based on the results of the correlation analysis, the following optimal parameters of the improved root crop head cleaner were obtained: the location of the ends of the rubber cleaning blades relative to the soil surface, i.e., the parameter should not exceed 1.5 cm. The angular velocity of the counter-rotating movements of the cleaning shafts should correspond to the following range of values – 36.4...76.6 rpm. The translational speed of the cleaner should not exceed 2.0 m∙s–1. The obtained structural, kinematic, and operational parameters can be successfully used in design bureaus when designing advanced machines for harvesting various root crops, and in research institutions and universities when conducting modern research in the field of agricultural engineering

Chain trench excavators are widely used in the world for trenching in agriculture, laying underground cables, digging trenches. In this study, the research object is a small chain-type trench excavator. The purpose of the study is to evaluate and select the parameters of the chain loader to the machine productivity and evaluate the results of the experimental machine theory calculation. Experimental measurement parameters include machine speed when working, chain speed, blade distance adjustment on the chain. Research method is to conduct experiments using Taguchi method to design experiments and Minitab software to analyze data. Experimental results and numerical analysis determined that the optimal set of parameters was the distance of 2 cutting edges on the chain, the active sprocket rotation speed for the highest productivity. Compared with the results from the theory using the design, the deviation of the optimal parameters is less than 5%. Experimental process design and parameter influence analysis by Taguchi method, ANOVA analysis have identified reasonable parameters, highest productivity target.

Blisks subjected to rough machining for channel creation must undergo finishing processes, and such processes must achieve the required tolerance limits. A high-quality surface finish and predictable long tool life are critical for the finish milling of blisks. Accordingly, the aim of this study was to optimize parameters for the finish machining of an Inconel 718 alloy monolithic blisk. Ball-cone mills were used to machine the blade surface at a constant depth. A sensory tool holder was used to collect cutting force signals during machining, and a digital microscope was used to examine tool wear. The surface texture measuring instrument was used to measure blisk blade surface roughness to evaluate processing quality. This study manipulated two cutting parameters, namely cutting speed and feed per tooth, and investigated their effects. The relationship between cutting conditions and machining efficiency was analyzed. According to the experimental results, we identified a set of optimal parameters at effective cutting speeds of 46.53 m/min, feed per tooth of 0.1 mm/tooth, and depth of cut of 0.05 mm for marginal tool wear and fast cutting speeds. Then the corresponding tool life was estimated by using the derived parameters.

In this paper, the objective function is effectively optimized by improving the fitness function in the computer algorithm. The improvement mainly focuses on adjusting the weighting coefficients of completion time, load balance and execution cost. The article then proceeds to optimize the algorithm’s parameters based on the algorithm’s optimal parameterization criterion, and designs a hybrid hill-climbing-simulated annealing optimization algorithm based on the parameterized model. To verify the safety of the algorithm, avalanche effect experiments were conducted in the study. The experimental results show that when the number of iterations is 14, the number of changed bits reaches 32, indicating that the algorithm is susceptible to the avalanche effect. In addition, for the application effect of the algorithm, the study was tested in the Oliver30 dataset. When the number of iterations reaches 25000 times, the algorithm has reached the optimal value distance 432.82, which shows the superiority in urban path recognition performance. Meanwhile, the algorithm has achieved an accuracy 0.8286 for feature recognition in remote sensing datasets, with a maximum classification accuracy of more than 90%. The study provides critical practical data and theoretical support for further application of the computer algorithm.

Relevance. Wastewater of knitting industry contains various types of dyes, synthetic surfactants, mineral salts and suspended solids in values requiring deep cleaning. It is advisable to carry out deep cleaning of these drains on non-pressure filters, which do not require large expenses and are easy to operate. We gave preference to frame-filling filters. First of all, it allows significant increase in filtration rate, and its two layers with different fractions of filter materials significantly contributes to differentiated purification of wastewater from suspended solids of various sizes. Aim. To determine the maximum permissible values of technological parameters of the frame-filling filters operation (filtration rate and duration of the filter cycle) at which high filtration effect is provided through a highly porous material-crushed expanded clay. Objects. Wastewaters of the knitting industry and the effluents of the cotton and textile industries that are similar in their composition of pollution, as well as the identical effluents of some other branches of light industry. Methods. The experimental method was used on a laboratory frame-filling filter installation. The expanded clay used was obtained by the method of swelling low-melting clays and clay rocks during their rapid firing, followed by crushing to the state of sand. In general, the proposed technological methods are justified by those comparative and generalizing methods that can improve frame-filling filter operation. Results and conclusions. Based on the results of the conducted research, the following conclusions can be drawn: • Pronounced intergranular porosity (on average 1.6 times greater than that of quartz sand) allows expanded clay granules passing through a significant amount of waste water at relatively high filtration speeds (20–22 m h) and retain up to 70% of suspended solids • The duration of the filter cycle when using crushed expanded clay is at least 1.5 times longer than when using quartz sand • Due to the greater difference in the average coefficients of the shape of the filtering materials, more complete regeneration of filtering properties of crushed expanded clay compared to quartz sand is provided 2–3 minutes earlier, regardless of the initial concentration of suspended substances. • The filtering properties of crushed expanded clay during deep wastewater treatment of the knitted production with the main concentrated pollution indicators (color intensity, BODfull, COD and surfactants) practically do not concede the quartz sand properties. Besides, crushed expanded clay is much cheaper than quartz sand; it can be used on an equal footing with quartz sand for deep cleaning of low-turbidity and slightly colored industrial wastewater.

Implementing a high-efficiency hybrid energy generation system requires to comprehensively analyze the influences of multiple factors on the overall performance, including system layout, design parameters, energy resource endowments. For this purpose, this study developed a thermal-economic model for a 300 kW ORC-based hybrid solar-geothermal power generation system at four sites in China, which represents different solar and geothermal energy resources. The optimal configurations of the hybrid system have been obtained for the minimal levelized cost of energy (LCOE) under a certain annual electricity generation (E). The results show that the solar resources continue to play a dominant role in the proposed hybrid system, especially in optimizing the configuration of the system design parameters for the minimum LCOE. Comparing to the individual solar system, the hybrid power generation system significantly enhances its thermal-economic efficiency across the four selected sites, with a maximum increase of 25.34% in E and a maximum decrease of 16.28% in LCOE. Especially in regions with abundant shallow hydrothermal geothermal reservoirs but average solar resources, utilizing shallow geothermal water to preheat Organic Rankine Cycle (ORC) working fluids is a relatively simple yet efficient application of geothermal energy for power generation, worthy of further promotion and implementation.

Using a tuned mass damper (TMD) is one of the passive methods of controlling structural vibrations. This energy absorption system has a mass, a spring, and a damper attaching to the main structure and vibrating with it, reducing the dynamic response of the structure by preventing the intensification. Therefore, finding optimal parameters is one of the main essential issues in the study and design of tuned mass dampers. This study investigates the optimization of parameters of an adjusted mass damper to reduce the displacement and relative response of a multi-story structural system equipped with this damper. For this purpose, a 10-story frame with similar properties on each floor and a 10-story frame with different properties on each floor were modeled under seismic loading in OpenSees software. The optimum parameters were extracted by Matlab software, using the particle swarm optimization (PSO) algorithm, whale optimization algorithm (WOA), and the combination of these two algorithms (Hybrid PSO-WOA) and state space equations controlled the results. Comparing the results with the methods presented by other researchers showed that the proposed methods have good performance and are recommended as approximate and rapid methods for the optimal design of these dampers. [ABSTRACT FROM AUTHOR]

In this paper, a momentum acceleration-based matrix splitting iteration method is presented for solving generalized absolute value equation. The convergence of the accelerated iteration method is studied in detail. And the optimal iteration parameters are studied. In particular, we present the approximate optimal iteration parameters which are independent of the number of iterations. Numerical experiments show that the proposed method with suitable parameters is efficient and accelerate the convergence performance with less CPU time and the number of iteration steps than some existing iteration methods. [ABSTRACT FROM AUTHOR]

Because of the unclear understanding of the characteristics associated with coupled rock breaking using multiple water jets, a numerical model combining smoothed particle hydrodynamics (SPH) and the finite element method (FEM) was established to investigate the rock-breaking capacity of a high-pressure, double-stranded water jet structure. The effectiveness of this model was verified through field experiments. The study further examined the specific energy required for rock breaking using the high-pressure double water jets and analyzed the effects of jet pressure, nozzle diameter, jet impact angle, and impact point spacing on rock-breaking volume. The results demonstrate that the rock-breaking ability of a high-pressure double water jets is better than that of a single water jet. When the impact angle of the high-pressure double water jets was 15° and the distance between impact points was 2.0 d, the rock damage effect was the best. By comparing the specific energies for rock breaking of a single water jet and a double water jet, it was concluded that the best rock-breaking nozzle diameter is 1.6 mm. Furthermore, an orthogonal testing approach was employed to determine the main and secondary factors influencing the rock-breaking energy of the high-pressure double water jet. The order of significance was found to be jet pressure > impact angle > impact point spacing > nozzle diameter. These findings provide valuable guidance and reference for application in the coal mining industry. [ABSTRACT FROM AUTHOR]

Given the high technical requirements for cleaning root crop heads from residues, the development of new, more advanced cleaners is an important and urgent issue. The research aims to improve the quality of the cleaning process by determining the optimal kinematic, structural, and operational parameters of a new root crop head cleaner from root residues. A new design of the root crop head cleaner was created, which allowed the use of cleaning elements with different mechanical properties and sizes, and changing its kinematic parameters depending on the crop it processes. A new experimental setup was also made to install this cleaner and change its operational parameters. A new mathematical model of a multifactorial experiment was developed for the study. Based on the results of the field experimental study, correlation analysis, and statistical numerical calculations using a computer, the optimal design, kinematic, and operational parameters of the improved cleaner were determined, at which the highest quality of cleaning (the lowest amount of stover residues per linear metre) is observed. Based on the results of the correlation analysis, the following optimal parameters of the improved root crop head cleaner were obtained: the location of the ends of the rubber cleaning blades relative to the soil surface, i.e., the parameter h should not exceed 1.5 cm. The angular velocity ω of the counter-rotating movements of the cleaning shafts should correspond to the following range of values - 36.4...76.6 rpm. The translational speed V of the cleaner should not exceed 2.0 m⋅s-1. The obtained structural, kinematic, and operational parameters can be successfully used in design bureaus when designing advanced machines for harvesting various root crops, and in research institutions and universities when conducting modern research in the field of agricultural engineering [ABSTRACT FROM AUTHOR]

In this paper, we propose a modified generalized SOR-like (MGSOR) method for solving an absolute value equation (AVE), which is obtained by reformulating equivalently AVE as a two-by-two block nonlinear equation and by introducing the transformation P y := | x | with a general nonsingular matrix P. The convergence results of the MGSOR method are obtained under certain assumptions imposed on the involved parameters. Furthermore, the optimal parameters minimizing the convergence rate of the MGSOR method for solving AVE are studied in detail. Numerical experiments further illustrate that the MGSOR method is efficient and has better performance than some existing iteration methods in aspects of the number of iteration steps and CPU time. [ABSTRACT FROM AUTHOR]

The object of research reported in this work is the fluctuations of the discharge current in Hall thrusters. The presence of significant fluctuations in the discharge current in Hall thrusters causes a significant deterioration of the thruster parameters – thrust, specific impulse, and efficiency. The task addressed in the current work relates to determining the main factors that affect the conditions for the occurrence of discharge current fluctuations, finding ways to reduce them, and obtaining optimal values of the parameters of the Hall thruster. The review of literary sources revealed that the specified problem is typical and has not yet been solved. In order to solve this problem, studies of the ST-40M Hall thruster were carried out in order to determine the main factors that have the greatest influence on the occurrence of oscillations and means of reducing the oscillations of the discharge current. The result of the research determined that the fluctuations of the discharge current depend most significantly on the parameters of the magnetic field in the acceleration channel of the thruster. The parameters of the magnetic field are determined by the magnitude of the currents of the thruster electromagnet coils, and the nature of oscillations, amplitude, and frequency may differ significantly with a slight change in the coil currents. As a result of the study, it was found that for the values of the currents of the coils of the magnetic system of the thruster, for which the level of fluctuations of the discharge current is minimal, the average value of the discharge current of the thruster also takes a minimum value. The research made it possible to determine the optimal operating modes of the Hall thruster, which ensure, at a given level of specific power, the maximum values of thrust, specific impulse, and thruster efficiency. The conclusions from the study could be useful for most developers of electric propulsion systems based on Hall thrusters [ABSTRACT FROM AUTHOR]

Radiometric correction is one of the most important preprocessing parts of unmanned aerial vehicle (UAV) multispectral remote sensing data analysis and application. In this article, a back propagation (BP) neural network-based radiometric correction method (BPNNRCM) considering optimal parameters was proposed. First, we used different UAV multispectral sensors (K6 equipped on the DJI M600, D-MSPC2000 equipped on the FEIMA D2000) to collect training, validation, testing and cross-validation data. Second, the radiometric correction results of BP neural network with different input variables and hidden layer node number were compared to select the best combination of input parameters and hidden layer node number. Finally, the radiometric correction accuracy and robustness of BP neural network considering the optimal parameters were verified. When the number of nodes in the input layer was five (digital number, UAV sensor height, wavelength, solar altitude angle, and temperature) and the number of nodes in the hidden layer was eight, the BP neural network had the best comprehensive performance in training time of train set and accuracy of validation/test set. In the aspect of accuracy and robustness, the absolute errors of test and cross-validation images' surface reflectance obtained by the BPNNRCM were all less than 0.054. The BPNNRCM had smaller average absolute error (0.0141), mean squared error (0.0003), mean absolute error (0.0141) and mean relative error (7.1%) comparing with empirical line method and radiative transfer model. In general, the research results of this article prove the feasibility and prospect of BPNNRCM for radiometric correction of UAV multispectral images.

An electromagnetic inertial mass damper (EIMD) is an inerter-based damper that can significantly enhance the seismic performance of a frame structure. However, the stochastic seismic analysis of a base-isolated structure (BIS) with the EIMD subjected to earthquake ground motions has rarely been reported. Based on a probabilistic framework, this paper studies the stochastic seismic responses of the BIS with the EIMD subjected to seismic excitations considering three typical soil conditions. The analytical solutions of the response variances of a two-degree-of-freedom (2DOF) BIS-EIMD system are derived considering both stationary and non-stationary seismic excitations. A parametric study on the BIS-EIMD system subjected to stochastic seismic excitations modeled by filtered Kanai-Tajimi spectrum is conducted to investigate the different seismic responses under firm, medium, and soft soil conditions, and the corresponding optimal inertance and damping of the EIMD are obtained by minimizing the stochastic seismic responses of the superstructure or the base floor. The results of the 2DOF BIS-EIMD system indicate that the optimal EIMD achieves comparable control performance under the three soil conditions, but the optimal parameters of the EIMD vary significantly under different soil conditions. Under soft soil conditions, the BIS-EIMD system requires a much larger inertance setting compared with that of the firm and medium soil conditions. A numerical simulation of a seven-story isolated building with an EIMD is conducted considering both artificial seismic excitations and real earthquake ground motions. Numerical results show that the EIMD is capable of significantly suppressing the seismic responses of both the base floor and the superstructure, which is better than that of a conventional viscous damper. [ABSTRACT FROM AUTHOR]

The purpose of this study was to apply infrared-assisted spouted bed drying (IRSBD) technology for Areca taro drying and to investigate the effects of different parameters on its drying quality. Specifically, in order to determine the suitable conditions for IRSBD, the effects of different drying temperatures (45 °C, 50 °C, 55 °C, and 60 °C) and cutting sizes (6 × 6 × 6 mm, 8 × 8 × 8 mm, 10 × 10 × 10 mm, and 12 × 12 × 12 mm) on the drying characteristics, temperature uniformity, and quality properties (including colour, rehydration ratio, total phenol content, total flavonoid content, and antioxidant activity) of Areca taro were studied. The results showed that the optimal drying condition was the sample with a cutting size of 10 × 10 × 10 mm and drying at 50 °C, which yielded the dried sample with the best colour, highest total phenol and flavonoid contents, maximum antioxidant capacity, and rehydration ratio.

The subject of research- the process of human skeletal muscles electrical stimulation during medical therapy. The subject of the study is a mathematical model of electrostimulation characteristics, which links the amplitude of muscle contraction and the stimulating effect amplitude. The current work develops a mathematical model in the form of an analytical expression to describe the muscle contraction amplitude dependence on electrical stimulus amplitude. Tasks to be solved: to analyze the dependence peculiarity of muscle contraction amplitude in stimulating impulse amplitude; conduct structural and parametric identification of the model; compare the results obtained using practical data, evaluate the model accuracy; use the obtained model for analytical description with the aim of a priori determination of the optimal stimulus amplitude. Methods used mathematical modeling method, methods of structural and parametric identification of models, approximation methods, parametric optimization methods, mathematical analysis methods. Results obtained an analytical model in the form of a 5th degree polynomial is proposed, which reflects the dependence of muscle contraction amplitude in the stimulus amplitude; the degree of the polynomial is selected and the coefficients of the model are obtained using parametric optimization; a model trajectory was built and the accuracy of modeling was estimated; an equation was obtained and its possible solutions were found to determine the optimal value of the stimulus amplitude; the practical application of the research results was substantiated. The results obtained can be used in the selection of individual effects of electrical stimulation during one session, as well as with extrapolation during the entire rehabilitation process. Scientific novelty: an analytical description showing the dependence of skeletal muscle contraction amplitude on the electrical stimulus amplitude was obtained, which allows determining individual optimal parameters of electromyostimulation.

An algorithm for determining the optimal parameters of an elliptical road bridge made of concrete blocks is proposed. The arch section heights are determined from the condition that the height of the concrete compressed zone should not be less than half the section height at any position of the automobile load. To solve the problem by the finite element method in physically nonlinear formulation, the principle of possible stress states is used. The nodes equilibrium equations of the arch are compiled using the possible displacements principle. The arch internal forces by a finite element length are approximated with linear functions, the concrete deformation diagram is represented in a piecewise-broken curve. Also, to determine the bearing capacity reserve of the optimal arch, the arch calculations were performed with a gradual increase in the automobile load up to destruction. Three options for the vehicle load location were considered. The optimal parameters of an arched road bridge with a span of 12 meters and its bearing capacity have been determined. It is shown that the arch destruction occurs with an increase in the load from the car by about 1.6 times.

Remote sensing has evolved through the appearance of several approaches. Object-based image analysis is a compelling approach to land use classification, object detection, and change detection in each environment. This paradigm is based on a critical and fundamental segmentation step. However, this step is highly dependent on the determination of the optimal parameters to be achieved. In this sense, methods have been invented to define the optimal segmentation parameters. This article presents an updated review of methods for defining optimal segmentation parameters. For this purpose, pertinent articles published in the main remote sensing journals from the emergence of the concept of object-based image analysis and segmentation to the present were used. The main aim is to provide a precise and detailed review of the different approaches previously presented. The originality of this review resides in the survey of all methods from conventional to the most recent with a discussion of these approaches. The results show that despite the advances in this field of research, most studies use the manual trial-and-error method. Conversely, state-of-the-art methods tend to determine the optimal parameter per type of geographic object and the adaptive calculation of segmentation parameters. Furthermore, the leading methods identified rely on supervised and unsupervised measures similarly, most of which use homogeneity measures. In contrast, a balance between intra- and inter-segment homogeneity and heterogeneity measures are more relevant. A distinction is made between pre-estimation and posterior parameter estimation methods. [ABSTRACT FROM AUTHOR]

Exopolysaccharides (EPSs) are highly heterogeneous natural polymers, can exhibit some unique bio-logical activities, such as anti-oxidation, inflammation regulation, anticancer and anti-viral activities, etc. A new type of EPS was obtained from the fermentation supernatant of Lactiplantibacillus plantarum YT013. However, the low yield of EPS posed a challenge for further research and application. Therefore, in this study, the production process of EPS was optimized, and anti-cancer cells proliferation activity was investigated. Identified the best single-factor conditions for EPS production, including initial pH 6, inoculation amount 5% (v/v), temperature 37°C, cultivation time 36 h, glucose 3% (w/v), soy peptone 1.5% (w/v), KH2PO4 0.3% (w/v). Under these conditions, the maximum production of EPS reached 0.630 mg/mL, which is 1.31 times higher than that before optimization. Concurrently, the nonlinear model was used for fitting, and it was found that the Voigt nonlinear model was in better agreement with the optimization results, which can be used as an effective tool for optimizing EPS production conditions. Furthermore, the anti-proliferative activity of EPS was evaluated using the human gastric cancer AGS cell line in vitro. MTT assay revealed a strong inhibitory effect of EPS on AGS cell proliferation. Additionally, flow cytometry analysis indicated that EPS promoted apoptosis in AGS cells. Lactiplantibacillus plantarum YT013 EPS, as a biodegradable and nontoxic natural active substance, shows potential as a natural antitumor substance. [ABSTRACT FROM AUTHOR]

In this paper, a damped one degree-of-freedom system equipped with a friction dynamic vibration absorber is considered. The optimal parameters: tuning frequency ratio and friction slip load are derived for various excitations: harmonic force, random force, harmonic base acceleration, and random base acceleration. The random excitation is modeled as Gaussian white noise, with constant power spectral density. First, a linearization technique is used to solve the equations of motion. Then, the optimization is conducted analytically for the undamped system, it is based on viscous absorber parameters. Finally, explicit formulas for the damped system are determined using curve fitting methods. The present paper has the advantage of determining analytically the optimal parameters of the friction absorber. It is found that the proposed formulas lead to optimal response, rapidly and accurately. [ABSTRACT FROM AUTHOR]

The present contribution deals with the possibility of using the PI-Control method in order to perform a Hybrid Fire Test (HFT) with a force-controlled procedure (FCP). Such a method may be applied in two ways where the instantaneous error is calculated in term of displacement or in term of force. Like the displacement-controlled procedure (DCP), stability of the HFT results can be ensured by an appropriate design of the values of the gains matrix, which depends on the estimation of the initial stiffness of the Physical Substructure (PS) as well as the chosen value of the eigenvalues. This paper will demonstrate how it is possible to determine optimal parameters in order to ensure the stability of a HFT when using such a method. In addition, it will be shown that, on the contrary to the recommendations for the use of the PI-Control method with the DCP, the initial stiffness of the PS should be underestimated rather than overestimated when the FCP is used. For illustrative purpose, several virtual HFTs have been implemented and analysed. [ABSTRACT FROM AUTHOR]

An automatic rice-filling device for lotus root with glutinous rice was developed based on the process of artificial filling. In order to find the best parameters for the vibrating rice-filling device—feeding speed, filling height, funnel diameter, amplitude, and frequency—so as to reduce the time and improve the mass of rice filling, EDEM software (EDEM 2022) was used to conduct numerical simulation of the process and analyze the influence of various factors on the rice-filling time. The optimal combination of parameters for the highest quality of rice filling was determined as follows: rice feeding speed, 1.4 kg/s; height of rice filling, 30 mm; funnel diameter, 55 mm; amplitude, 0.6 mm; frequency, 50 Hz; and filling time, 3.4 s. The simulation experiment results are in good agreement with the prototype experiment, achieving the purpose of improving the efficiency of rice filling. This study provides theoretical guidance for research on an automatic rice-filling device for lotus root with glutinous rice. [ABSTRACT FROM AUTHOR]

Plastic parts in retired passenger vehicles are derived from non-renewable oil resources, and recycling them can conserve energy and reduce the burden on the environment. Effective separation is the premise of recycling vehicle plastics, and electrostatic separation is a clean and efficient method of plastic separation. On the basis of a self-developed, two-stage electrostatic separation equipment, this study investigated the high-voltage electrostatic separation of polyamide (PA), polyethylene (PE), and polypropylene (PP) mixtures. First, the single-factor experiment method was used to explore the influence of voltage, electrode spacing, and electrode inclination angle on the separation results. Second, the response surface methodology was employed to comprehensively analyze the effects of voltage, electrode spacing, and electrode inclination angle on the recovery rates of the three particles and their interactions. The optimum parameters for the secondary electrostatic separation of the three particles were determined to be 44 kV voltage, 156 mm electrode spacing, and 10° electrode inclination. Experimental verification showed that after the two-stage, electrostatic separation device was optimized through the response surface methodology, the purity of the PA particles reached 98.56%, and the recovery rate reached 96%. The purity of the PP particles reached 81.93%, and the recovery rate was 87.5%. Meanwhile, the purity of the PE particles reached 86.11%, and the recovery rate was 73%. This research provides a reference for the multi-stage, high-voltage, electrostatic separation of various automotive plastic particles. [ABSTRACT FROM AUTHOR]

The Accelerated Hermitian/skew-Hermitian type Richardson (AHSR) iteration methods are presented for solving non-Hermitian positive definite linear systems with three schemes, by using Anderson mixing. The upper bounds of spectral radii of iteration matrices are studied, and then the convergence theories of the AHSR iteration methods are established. Furthermore, the optimal iteration parameters are provided, which can be computed exactly. In addition, the application to the model convection-diffusion equation is depicted and numerical experiments are conducted to exhibit the effectiveness and confirm the theoretical analysis of the AHSR iteration methods. [ABSTRACT FROM AUTHOR]

Learning to pronounce hijaiah letters needs to be assessed objectively, so it is necessary to form digital audio resulting from the synthesis of Harmonic Plus Residual (HPR) modeling, which conducted with two pronunciation methods, taskin and tasydid. The experiment consists data acquisition, signal cutting, framing and windowing, detection of fundamental and harmonic frequencies, synthesis of HPR, to produce synthetic signals. The results of the synthetic signals then analyzed qualitatively by signal spectrogram analysis and scoring. From the experimental results, it can be concluded that this study was ultimately unable to determine the best HPR parameters, but concluded that the tasydid method was the best method for learning pronunciation and for the HPR model synthesis. This is because the tasydid method with different parameters but all of them can produce good synthetic signal, both in terms of comparative analysis of similar signal spectrograms and from the results of scoring with an average value of 10. On the other hand, the taskin method harf shows unsatisfactory results, where the synthetic sound is mostly just noise, so the scoring results is under 9, and is reinforced by the results of the spectrogram comparison between the original and synthetic signals which visually different.