Method For Calculation Of Parameters Research Articles

Метод расчета интегральных показателей качества и рационального использования земель сельскохозяйственного назначения в QGIS

Due to the imperfection of the regulatory regulation of the agricultural land use, the lack of fixed indicators that characterize rational use of this land category, the authors, solve the task of calculation method for integral parameters, characterizing the quality and rational use of such lands. The solution was based on the analysis of the results developed by existing scientific schools in the given field and our own research, including the set of particular parameters, their subdivision into groups, the variant of determination of their relative significance (weight) in final assessment. The fundamental aspect of the assessment system is emphasized, due to the diversity of the realization of their natural potential by agricultural areas similar in natural properties, which required the implementation of two groups of indicators – the quality and rational use of agricultural land. In order to determine the integral indicators of quality and rational use of agricultural land, the authors have developed an algorithm for calculating them in the geographic information system QGIS, consisting of certain stages. Automatic calcu-lation of integral indicators significantly speeds up and simplifies the process of analyzing the state of land use in a particular region, avoids mechanical errors in calculations.

Backstepping control strategy for induction motor with rotor flux and load torque observers

This paper deal with Backstepping control strategy for induction motor drive, using rotor flux and load torque observers. The proposed study uses a modified motor model with new variables, and Luenberger observers for both rotor flux and load torque. This work proposes a precise calculation method for controller parameters based on response time and damping coefficient. Simulation is performed in Simulink, results show that Backstepping works well by adding observers.

A novel acquisition approach for heat transfer coefficient during periodic cooling process

Temperature is an important parameter affecting the micro-structure of slab and an important guarantee to improve the performance index of metallurgical products. However, the temperature level is affected by the heat transfer coefficient. Taking laminar cooling as an example, a method for calculating the heat transfer coefficient of a system with periodic characteristics is proposed in this study. Firstly, it was assumed that the distribution of heat transfer coefficient is a piecewise function composed of positive half wave of sine function and line function. The calculation methods of characteristic parameters, through structural parameters and operating parameters, in three cases of ?separation?, ?adjacent? and ?intersection? are given. Secondly, heat transfer model of slab was established. Surface temperature and center temperature distribution of slab were compared with the test results. The relative errors of surface and center temperature were 2.46% and 1.33%, respectively, which verified the accuracy of this method. Finally, the coupling relationship between the characteristic parameters in the heat transfer coeficient distribution function is obtained by calculation. Compared with the methods presented in the literature, this method reduces the number of unknown parameters while ensuring the accuracy of the model, and gives guidance on how to change the slab temperature and improve product performance by adjusting the structure and operating parameters.

Design of thermal management system for lithium battery at low temperature

The battery capacity of lithium battery will decay at low temperature, and the battery performance will seriously decline at extremely low temperature, and the electrolyte will also freeze. Therefore, lithium batteries need to be preheated at low temperature. This paper selects 22 Ah lithium iron phosphate battery as the research object. The preheating scheme of PTC aluminum plate heating plate for lithium battery was designed by thermal parameter calculation and simulation method. The preheating scheme was optimized by changing the number (2, 3 and 4 pieces) and size (120%, 80% and 60% lithium battery size) of PTC heating plate. The results show that when heating 6 pieces of 22 Ah lithium iron phosphate battery, the preheating effect of 3 pieces of PTC heating plate close to the size of lithium battery is the best.

Analytical Study on Surface Settlement Troughs Induced by the Sequential Excavation of Adjacent and Parallel Tunnels in Layered Soils

In this paper, the settlement troughs induced by the excavation of adjacent and parallel tunnels in layered soils were studied. Firstly, a trough width parameter calculation method in layered soils was established based on the propagation model of the plastic zone and unloading disturbance zone. Secondly, the mechanism of the superposition disturbance between parallel tunnels is analyzed, and a method for calculating additional settlement trough is proposed. Finally, the applicability of the proposed model was demonstrated with two case studies of the parallel tunnels. The following conclusions were obtained: the difference of soil properties in layered soils had a significant influence on the width parameter of surface settlement trough; a Gaussian curve can describe the additional settlement caused by superimposed disturbance; and finally, the relationship between the ground loss induced by superposition disturbance and the ground loss induced by the preceding tunnel was approximately linear. The model presented in this paper is highly effective and convenient for use in practice and extends the calculation method of surface settlement trough based on the Gaussian curve.

Design method research of a radiation-resistant zoom lens

In a strong nuclear radiation environment, the life of a traditional zoom lens is extremely short. To improve the life of the zoom lens, a novel method to design the zoom optical system is proposed, in which the front fixed group is all made of Silica lens with stronger irradiation performance. Firstly, the radiation-resistant performance of the glass lens is tested, and the transmittance of the optical system is analyzed. Then, a specific zoom optical system was proposed for the problem of difficult chromatic aberration correction in the front fixed group, and a calculation method of the initial structure parameters is analyzed theoretically. Finally, a 6× radiation-resistant zoom optical system is designed by using only two specific radiation-resistant glass materials. The imaging experiment demonstrates the better imaging performance of the radiation-resistant zoom system, which verifies the feasibility of the design method proposed in this paper.

Analysis of the Deformation Characteristics of Loess Based on Thermal–Mechanical Coupling under an Energy Internet

In response to the major challenges faced by China’s transition to green low-carbon energy under the dual-carbon goal, the use of energy Internet cross-boundary thinking will help to develop research on the integration of renewable clean energy and buildings. Energy piles are a new building-energy-saving technology that uses geothermal energy in the shallow soil of the Earth’s surface as a source of cold (heat) to achieve heating in winter and cooling in summer. It is a complex thermomechanical working process that changes the temperature of the rock and soil around the pile, and the temperature change significantly influences the mechanical properties of natural loess. Although the soil temperature can be easily and quickly obtained by using sensors connected to the Internet of Things, the mechanical properties of natural loess will change greatly under the influence of temperature. To explore the influence of temperature on the stress–strain relationship of structural loess, the undrained triaxial consolidation tests were carried out under different temperatures (5, 20, 50 and 70∘C) and different confining pressures (50, 100, 200 and 400[Formula: see text]kPa), and a binary-medium model was introduced to simulate the stress–strain relationship. By introducing the damage rate under temperature change conditions, a binary-medium model of structural loess under variable temperature conditions was established, and the calculation method of the model parameters was proposed. Finally, the calculated results were compared with the test results. The calculation results showed that the established model has good applicability.

Application of AMOGWO in Multi-Objective Optimal Allocation of Water Resources in Handan, China

The reasonable allocation of water resources using different optimization technologies has received extensive attention. However, not all optimization algorithms are suitable for solving this problem because of its complexity. In this study, we applied an ameliorative multi-objective gray wolf optimizer (AMOGWO) to the problem. For AMOGWO, which is based on the multi-objective gray wolf optimizer, we improved the distance control parameter calculation method, added crowding degree for the archive, and optimized the selection mechanism for leader wolves. Subsequently, AMOGWO was used to solve the multi-objective optimal allocation of water resources in Handan, China, for 2035, with the maximum economic benefit and minimum social water shortage used as objective functions. The optimal results obtained indicate a total water demand in Handan of 2740.43 × 106 m3, total water distribution of 2442.23 × 106 m3, and water shortage of 298.20 × 106 m3, which is consistent with the principles of water resource utilization in Handan. Furthermore, comparison results indicate that AMOGWO has substantially enhanced convergence rates and precision compared to the non-dominated sorting genetic algorithm II and the multi-objective particle swarm optimization algorithm, demonstrating relatively high reliability and applicability. This study thus provides a new method for solving the multi-objective optimal allocation of water resources.

Weighted analysis and simplified calculation method of automotive exhaust thermoelectric generator performance

This paper focuses on evaluating the performance of automotive exhaust thermoelectric generators (AETEGs) under actual vehicle driving conditions. The exhaust gas temperature and mass flow rate under driving conditions are in a transient state, which directly affects the performance of the AETEG and therefore cannot be ignored. To reflect this, we built a numerical model of the AETEG and developed a weighted analysis method based on the exhaust conditions in standard test cycles to obtain the output performance and optimal thermoelectric module area of the AETEG. The results show that, compared with the results without using the weighted analysis, the maximum power output and the optimal module area increased by 5.2 % and 56.4 %, respectively, after using this method. In addition, for engineering applications, this paper presents a simplified calculation method for the performance parameters of an AETEG. Compared with the numerical calculation method, the simplified calculation method, whose calculation accuracy meets the requirements of general engineering applications, is more convenient and efficient, and has certain guiding significance for the practical application of AETEGs.

An interpolation method based on adaptive smooth feedrate scheduling and parameter increment compensation for NURBS curve

Compared with the traditional line/circle interpolation, non-uniform rational B-splines (NURBS) interpolation has more efficient and high-quality advantages in free-form curve/surface modeling. In order to obtain high efficiency and stable interpolation feed motion, a NURBS interpolation method with adaptive smoothing federate scheduling and parameter increment compensation is studied. Firstly, according to the curvature constraint, the adaptive feedrate is obtained and the segmentation of the NURBS curve is completed. Then, in order to avoid the problem of feeding speed overrun, the improved S-shape acceleration/deceleration control is adopted to adjust the jerk. The adjacent segments meeting the combined planning conditions are treated comprehensively. Secondly, aiming at the problem of velocity error in interpolation point parameter calculation, an interpolation parameter calculation method based on parameter increment compensation is proposed to reduce the velocity fluctuation and improve the interpolation point parameter calculation accuracy. Finally, the effectiveness of the proposed method is verified by simulation and experiment. The results show that the algorithm is effective.

Measurement and calculation method of attitude parameters of roadheader

Measurement and calculation method of attitude parameters of roadheader

Особенности проектирования турбогенератора с повышенной частотой вращения 6000 об/мин

Object and purpose of research. The object under study is a 36 МW turbo-alternator (TA) with electromagnetic excitation and a high rotational speed of 6000 rpm, which can be used as an option for ac electric power source of 100 Hz in ship electric power systems with a turbo-alternator plant. The purpose is to perform electromagnetic calculations to determine TA main data and technical characteristics, including the stator and rotor pack, their design, mass of active materials, etc. for comparison with a TA of the same power but 3000 rpm. Materials and methods. The studies are based on research and engineering data about investigations and design of double-pole industrial TA of 50 Hz as well as TA with a high current frequency (100 Hz and higher). For this purpose, the known formulas were used to estimate the size of TA active elements, excitation forces of stator and rotor windings, as well as methods for calculation of main TA parameters and technical characteristics. Main results. Design specifics of TA with a high rotational speed of 6000 rpm is identified, and results of electromagnetic estimations are obtained for a specific 36 MW turbo-alternator of 100 Hz with a forced close cycle cooling and better mass and size characteristics. Conclusions. The obtained results are of practical value, showing feasibility of developing a version of 36.0 МW TA with a rotational speed of 6000 rpm and significantly reduced specific mass and size characteristics – tentatively by 35–40 % as compared to the existing TA of the same power but with a speed of 3000 rpm.

Универсальный метод расчета отражательных оптических характеристик двугранного отражателя с ламбертовскими гранями по методу лучистого сальдо

Object and purpose of research. This paper discusses the ways to improve current calculation method for reflection parameters during remote laser detection and ranging by means of a dihedral reflector with Lambert surfaces equal to reflection coefficients of each surface as per the generalized method of radiative balance. The study also discusses the evolution of optical methods and analytical research tools in this domain, as well as laser signature calculation for various ships and other structures. Materials and methods. Analytical calculation methods, software, calculation methods for remote laser detection and ranging taking into account optical parameters and reflection coefficient of dihedral reflectors used to calculate laser signature of ship structures. Main results. Improved efficiency and accuracy of calculation methods for laser detection and ranging with respect to dihedral reflectors for surface ships. Conclusion. Calculation methods of remote laser detection and ranging suggested in this paper offer additional capabilities in lidar signature measurements of ships and other structures.

Design and Verification of Flush Air Data Sensing Module with Navigation and Temperature Information

For aircraft which move in the atmosphere, the angle of attack and angle of sideslip cannot be measured precisely. This limits the precision of guidance and control systems, so the flush air data sensing system module with navigation and temperature information is designed for atmosphere parameter calculation. In this work the traditional parameter calculation method is improved, and a new algorithm which combines pressure data, temperature data and navigation data to calculate the atmosphere parameters is proposed. A ground experiment test scheme with a simulated flight environment is designed and the measured data is fitted and filtered to complete the experiments. The flush air data sensing module gets pressure data and temperature data of the atmosphere with sensors, and the measured data is integrated with navigation information to calculate the aircraft parameters of the angle of attack, angle of sideslip, dynamic pressure, static pressure, Mach number and so on. Calculated parameters can be transmitted to guidance and control systems to improve the attitude and trajectory precision for an aircraft. Experimental results show that the software and hardware of the flush air data system module with navigation and temperature information work well, and communication of various devices is normal. The flight status of aircraft can be precisely calculated online, which provides a useful reference for prospective wind tunnel experiments and flight tests.

Realization of GPS Dynamic Hijacking Based on Software Radio

GPS positioning technology has a wide range of use scenarios, but due to the known characteristics of GPS signal open reception and modulation methods, many solutions can easily deceive GPS signals. Once this technology is abused in violation of regulations, it may cause major safety and property losses. In order to better study the anti-hijacking technology of PGS signals, this article starts with the generative dynamic hijacking of PGS, gives the implementation method based on software radio, and further learns the code phase and dopper between asynchronous hijacking and synchronous hijacking through software radio. The compensation calculation method of Leer frequency shift parameters, and verified the effect of the software radio’s GPS dynamic hijacking implementation method through examples, and provide theoretical support for the design and improvement of future anti-hijacking systems.

Research on dynamic current sharing method of parallel connected IGBT modules for NPC three level converters

The parallel connection of IGBTs has been being applied in high power neutral point clamped (NPC) three level converters. This paper investigates the impact of gate parameters (gate resistor and capacitance) on dynamic current imbalance of parallel connected IGBT for NPC three level converter. A gate parameters calculation method is proposed in the paper, and the delay time and collector current difference can be analysed quantitatively. Experimental results have shown the effectiveness of the method.

Simulation Analysis of Current in Metal Sheath of Power Cable Considering Temperature Characteristics

This paper proposes a cable broadband circuit model considering the temperature characteristics. This paper establishes the equivalent circuit model of the cross-bonded power cable and proposes the broadband parameter calculation method considering the temperature. The cable parameters are calculated by the vector fitting method. Based on the operating current and cable temperature data of the cable on a certain day, the simulation analysis of the cable sheath current considering the temperature is carried out using Simulink. Finally, the simulation results show that the cable sheath current is significantly affected by temperature.

Generator stator windings ground fault diagnosis for generator–grid​ directly connected system of floating nuclear power plant

For floating nuclear power plants, the internal power system adopts the generator–grid directly connected structure. Generator ground fault diagnosis enables the protective device to adaptively determine the generator tripping control mode based on the fault degree, and shorten the troubleshooting time by fault location. To accurately calculate the ground fault current under different system operating modes, a real-time grounding capacitance parameters calculation method without injection devices is proposed based on third harmonic voltage. Using the fault component principle, the ground fault current is calculated including the fundamental and the third harmonic components. Through fuzzy membership function, the ground fault degree function is established including the ground fault current and the system overvoltage. It comprehensively reflects the damage degree of both the generator operating security and the system insulation security. According to the 60° phase-band distribution characteristic of the stator windings, a fault coil location method based on the windings’ electric potential distribution characteristics is proposed. PSCAD/EMTDC simulation results show that the proposed method has high computational accuracy.

Power estimation method of low-voltage distributed photovoltaic generation based on similarity aggregation

Regarding to the issue that there is no automatic data acquisition for low-voltage distributed photovoltaic generation, a power estimation method for low-voltage distributed photovoltaic generation based on similarity aggregation is proposed in this paper. Firstly, based on the time series power curve data characteristics of middle-voltage distributed photovoltaic generation and L2 norm distance, a middle-voltage distributed photovoltaic aggregation model is established, and a solution method of middle-voltage distributed photovoltaic aggregation based on K-means clustering is proposed; Secondly, based on the aggregation results of middle-voltage distributed photovoltaic, a parameter calculation method for the power estimation of low-voltage distributed photovoltaic based on geographical distribution and electricity data is proposed; Thirdly, considering the time series data characteristics of distributed photovoltaic changing with date, a strategy to determine whether to re-calculate the middle-voltage distributed photovoltaic aggregation and the power estimation parameters according to the cumulative error is proposed. Finally case studies are accomplished and the effectiveness of the proposed method are verified. The aggregation of middle-voltage distributed photovoltaic and the power estimation of low-voltage distributed photovoltaic, which is helpful to master the overall power generation of regional distributed photovoltaic, realize the observability of low-voltage distributed photovoltaic power generation, improve the safe operation level of distribution network, and has important theoretical and practical significance for serving the orderly development of distributed photovoltaic generations.

General method for replacing a thin lens with a thick lens with the same value of Seidel aberration coefficient of spherical aberration or coma.

The paper deals with the problem of replacing a thin lens with a thick lens having similar third-order aberration properties as the thin lens. The equations that make possible the calculation of parameters of the thick lens, which has the same value of focal length (or transverse magnification) and one of the Seidel aberration coefficients (either Seidel aberration coefficient of spherical aberration or Seidel aberration coefficient of coma) as the thin lens for given position of the entrance pupil and object, are derived. The application of the proposed method for calculation of parameters of the thick lens is shown in examples.