Accurate Calculation Model Research Articles

Electromagnetic Field Modeling and Optimization Design of Axial Magnetic Flux Eddy Current Brake Considering Non‐Ideal Factors

Accurate analytical calculation of electromagnetic field is the basis of research and optimization of axial magnetic flux eddy current brake, and structural optimization design is the key to improving system performance and reducing engineering construction costs. In order to establish an accurate analytical calculation model of electromagnetic field of axial magnetic flux eddy current brake, based on the two‐dimensional analytical calculation model of electromagnetic field, this paper comprehensively considers the influence of non‐ideal factors such as core saturation, transverse dynamic end effect and secondary skin effect on the electromagnetic characteristics of axial magnetic flux eddy current brake, and obtains an improved analytical calculation model of electromagnetic field by introducing corresponding correction coefficients, and verifies the accuracy of the analytical calculation model of electromagnetic field by comparing with the numerical calculation results of three‐dimensional electromagnetic field finite element model. On this basis, an improved multi‐objective particle swarm optimization algorithm is adopted to optimize the system design, so as to increase the electromagnetic braking torque, reduce the electromagnetic axial force and reduce the secondary mass. Finally, the accuracy of the above electromagnetic field analytical calculation model and optimization design results is verified on the experimental research platform of axial magnetic flux eddy current brake, which can provide theoretical basis for subsequent researchers to design and optimize the electromagnetic scheme. © 2025 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

The penetration crater characteristics of thick steel plate impacted by tungsten alloy projectiles

Abstract The mild steel target plates impacted vertically by tungsten spherical projectiles with different initial velocities and projectile diameters were studied by ballistic experiments and numerical simulation. The macroscopic properties of the penetration crater were analyzed by the depth, diameter, and overall shape of the crater. The results show that crater diameter and depth increase as initial velocity or projectile diameter increases. With the increase in velocity, the deformation and erosion of tungsten projectiles significantly increased. Specific kinetic energy is used to normalize the velocity and size of the projectile, the expression of crater depth and diameter varying with specific kinetic energy is given, which accuracy R2 is 0.8. Based on THOR theory and experimental data, the accurate calculation model of penetration depth versus projectile mass, initial velocity, and the area of the contact was obtained, with an accuracy of R2 of 0.97.

Influence of Compressive Strength and Steel-Tube Thickness on Axial Compression Performance of Ultra-High-Performance Concrete-Filled Stainless-Steel Tube Columns Containing Coarse Aggregates

With the increasing use of concrete-filled steel tubular (CFST) structures, exposed steel tubes are highly susceptible to corrosion, posing potential safety hazards. This study innovatively proposes the use of stainless-steel tubes instead of traditional carbon-steel ones and introduces coarse aggregates into ultra-high-performance concrete (UHPC), forming a coarse aggregate-incorporated ultra-high-performance concrete-filled stainless-steel tube (CA-UFSST). The inclusion of coarse aggregates not only compensates for the shortcomings of UHPC but also enhances the overall mechanical performance of the composite structure. Twenty sets of specimens were designed to analyze the influence of four parameters, including the coarse aggregate content, compressive strength, stainless-steel-tube thickness, and stainless-steel type on the axial compression performance of UHPC. The experimental results indicate that the failure mode of UHPC is related to the confinement ratio. As the confinement ratio increases, the failure mode transitions from shear failure to bulging failure. The addition of coarse aggregates enhances the stiffness of the specimens. Furthermore, this paper discusses the applicability of six current codes in predicting the bearing capacity of CA-UFSST and finds that the European code exhibits the best prediction performance. However, as the confinement ratio increases, the prediction accuracy becomes notably insufficient. Therefore, it is necessary to establish a more accurate calculation model for the axial compression bearing capacity.

Fast retrieval of XCO2 over east Asia based on Orbiting Carbon Observatory-2 (OCO-2) spectral measurements

Abstract. The increase in greenhouse gas concentrations, particularly CO2, has significant implications for global climate patterns and various aspects of human life. Spaceborne remote sensing satellites play a crucial role in high-resolution monitoring of atmospheric CO2. However, the next generation of greenhouse gas monitoring satellites is expected to face challenges, particularly in terms of computational efficiency in atmospheric CO2 retrieval and analysis. To address these challenges, this study focuses on improving the speed of retrieving the column-averaged dry-air mole fraction of carbon dioxide (XCO2) using spectral data from the Orbiting Carbon Observatory-2 (OCO-2) satellite while still maintaining retrieval accuracy. A novel approach based on neural network (NN) models is proposed to tackle the nonlinear inversion problems associated with XCO2 retrievals. The study employs a data-driven supervised learning method and explores two distinct training strategies. Firstly, training is conducted using experimental data obtained from the inversion of the operational optimization model, which is released as the OCO-2 satellite products. Secondly, training is performed using a simulated dataset generated by an accurate forward calculation model. The inversion performance and prediction performance of the machine learning model for XCO2 are compared, analyzed, and discussed for the observed region over east Asia. The results demonstrate that the model trained on simulated data accurately predicts XCO2 in the target area. Furthermore, when compared to OCO-2 satellite product data, the developed XCO2 retrieval model not only achieves rapid predictions (<1 ms) with good accuracy (1.8 ppm or approximately 0.45 %) but also effectively captures sudden increases in XCO2 plumes near industrial emission sources. The accuracy of the machine learning model retrieval results is validated against reliable data from Total Carbon Column Observing Network (TCCON) sites, demonstrating its ability to effectively capture CO2 seasonal variations and annual growth trends.

Study on current carrying capacity calculation model for dynamic capacity increase of carbon fiber reinforced composite core conductor

Abstract With the “dual-carbon” as the goal of the new power system construction gradually in-depth, transmission lines must have energy-saving capacity for the direction of development. A new type of large-capacity overhead transmission conductor is the carbon fiber reinforced composite core (CFCC) conductor. The conductor has high capacity, low loss, high-temperature resistance, low high-temperature sag, and other characteristics. It is one of the key technologies and equipment applied to the transformation of old overhead transmission lines to enhance its capacity. At the same time, it can also realize the dynamic transmission capacity regulation of the overhead line. The application of the prospect is very promising. The accurate assessment and calculation model for the conductor’s allowable current carrying capacity is the key core technical problem of the overhead transmission line dynamic capacity increase capability. The paper establishes a maximum allowable current capacity calculation model for carbon fiber-reinforced composite core conductors based on Morgan’s formula. The results of the load flow calculation are compared with the actual load flow test results to verify the calculation model, and the maximum error is 3.59%, which proves the reliability of the calculation model. On this basis, the influence of external environmental factors (ambient temperature, sunlight intensity, wind speed, and direction) on the maximum allowable current capacity of the conductor is discussed. The correlation coefficient of the model is analyzed.

Calculation of optical efficiency of the heliostat field based on Reverse Projection Box Counting Model

A more accurate and reasonable calculation model is proposed for the calculation of total optical efficiency, shadow blocking efficiency, cosine efficiency, atmospheric transmittance, collector truncation efficiency and output thermal power of heliostat field in tower solar photovoltaic power plant. In this paper, under the condition that the relevant parameters of heliostat field are determined, the Monte Carlo Ray Tracing method is used as the basis for the calculation of each optical efficiency. At the same time, the innovative Reverse Projection Box Counting Model is established to accurately identify whether there is a shadow blocking problem or not, and the differential idea is used to effectively solve the problem of repeated calculation of the blocking shadow area and the irregularity of the blocking area difficult to be calculated caused by one heliostat being blocked by multiple heliostats, so as to estimate the shadow blocking efficiency of the heliostat field more accurately. Finally, the heliostat field in Gansu, China, is taken as an example for calculation, and the results are compared with those of other scholars and the real value of the heliostat field to prove the superiority of the model constructed in this paper and the accuracy of the solution results.

A Minimized Measurement Scheme for Predicting HbA1c Using Discrete Self-Monitoring Blood Glucose Data Within 4 Weeks for People with Type 2 Diabetes.

Objective: To establish an accurate and robust calculation model for predicting hemoglobin A1c (HbA1c) for people with type 2 diabetes (T2D) by using the fewest discrete blood glucose values according to an irregular data set and propose an appropriate cost-effective and scientific scheme for routine blood glucose monitoring. Methods: By using two data sets obtained from 2017 to 2022, which involved 2432 people with T2D, ∼420,000 irregular blood glucose values, and 10,000 HbA1c values, multiple blood glucose monitoring schemes were designed and compared to find the optimal one. The data were structured and then fitted using a regularized extreme learning machine, and the results were evaluated on the basis of indicators such as mean absolute error (MAE), root mean square error, and the relevance analysis (R) value; the optimal scheme for routine blood glucose monitoring was determined by combining the accuracy and the cost and was compared with previous studies in terms of accuracy and stability. Results: Data fitting results for the chosen scheme: R = 0.8029 (P < 0.001), MAE = 0.3181% (95% confidence interval, 0.2666-0.3695%). Within the last 4 weeks before the prediction of HbA1c, a minimum of only seven fasting and seven postprandial blood glucose values are needed, of which are one fasting and one postprandial blood glucose values per 4 days. Compared with previous studies, the prediction model shows better accuracy and stability (P < 0.05), especially under the great glucose fluctuation group. Conclusion: A minimized calculation model for accurately and robustly predicting HbA1c using discrete self-monitoring of blood glucose data within 4 weeks for people with T2D has been established and provides a new reference for the design of a scheme for blood glucose monitoring. The diabetes care clinic of Peking University First Hospital (Registration Number: ChiCTR2300068139).

Establishing a nutrition calculation model for catering food according to the influencing factors of energy and nutrient content in food processing.

This study aimed to establish an accurate and efficient scientific calculation model for the nutritional composition of catering food to estimate energy and nutrient content of catering food. We constructed a scientific raw material classification database based on the Chinese food composition table by calculating the representative values of each food raw material type. Using China's common cooking methods, we cooked 150 dishes including grains, meat, poultry, fish, eggs, and vegetables and established a database showing the raw and cooked ratios of various food materials by calculating the ratio of raw to cooked and the China Total Diet Research database. The effects of various cooking methods on the nutritional composition of catering food were analyzed to determine correction factors for such methods on the nutritional components. Finally, we linked the raw material classification, raw and cooked ratio, and nutritional component correction factor databases to establish a model for calculating the nutritional components of catering food. The model was verified with nine representative Chinese dishes. We have completed the construction of an accurate and efficient scientific calculation model for the nutritional composition of catering food, which improves the accuracy of nutrition composition calculation. The model constructed in this study was scientific, accurate, and efficient, thereby promising in facilitating the accurate calculation and correct labeling of nutritional components in catering food.

Radiology Service Tariff Calculation Model Using the Activity Based Costing (ABC) Method at Naibonat Regional Hospital, Kupang Regency

Determination of health service tariffs also determines optimal health service outcomes. Determination of radiology examination rates at Naibonat Hospital until 2023 still refers to Regional Regulation No. 5 of 2012 concerning public service fees, where the determination of fees still uses the conventional calculation system, and there are changes in image processing modalities, tools, and materials used, this demands a rate adjustment. Calculation of rates using the Activity Based Costing (ABC) method, can be a solution to determine more accurate rates, supported by Pramawati's research (2021) which shows the results of determining rates are more accurate using the ABC method. The purpose of this study was to calculate the tariff pattern for radiological examinations at Naibonat Hospital using the ABC method and obtain an accurate tariff calculation model for radiological examinations. This research is a descriptive explorative study, with a quantitative approach using numerical data which aims to calculate a unit cost-based examination rate model by implementing an Activity Based Costing system on ultrasound examination of the abdomen, chest x-rays, abdomen, skull, and extremities. The data obtained was then subjected to qualitative analysis to obtain the steps for calculating tariffs using the ABC method. The results of this study indicate that the calculation model for radiological examination rates using the ABC method is valid. To find rates, first, determine the basic rate with the formula unit cost = direct cost + overhead, the results obtained are then calculated. Examination rates = cos unit + hospital services, so the examination rates at the Radiology unit of Naibonat Hospital, namely abdominal USG Rp 242.036, photo thorax Rp. 116,995, photo abdomen Rp. 150,321, photoskull Rp. 153,262, and a photo extremity Rp. 121,409.

Analytical calculation of mesh stiffness for spiral bevel gears with an improved global tooth deformation model

The paper proposes an efficient and accurate analytical calculation model of time-varying mesh stiffness (TVMS) for the spiral bevel gear. Firstly, an enhanced numerical loaded tooth contact analysis (NLTCA) model that considers both the global tooth and local contact deformations is developed. Based on Tredgold's approximation, spiral bevel gears are sliced into a series of spur gears. An improved global tooth deformation model is developed by accounting for axial tooth deformation and the effect of non-contacting tooth slices. The influence coefficient method is utilized to determine the local contact deformation. Subsequently, based on the results of the NLTCA model, a detailed calculation procedure for determining the TVMS of spiral bevel gears is described. Finally, some numerical examples are provided to illustrate the efficiency and accuracy of the proposed model through comparisons to finite element analysis (FEA) results. The proposed model can achieve satisfactory accuracy without FEA modification. Furthermore, ignoring the effects of the non-contacting tooth slices will lead to excessive elastic deformation when the length of the contact area across the tooth width is significantly shorter than the tooth width.

Study on Mechanical Calculation Model of Arch Ring in Freestanding Stone Cave-Dwelling

The freestanding stone cave-dwelling is a kind of arched and sheltered house built with stones in the Loess Plateau region of northwest China. Amazingly, before construction, this kind of cave-dwelling was not formally calculated and designed in theory, but only built on the experience passed down by predecessors. The arch ring is the main load-bearing component of the freestanding stone cave-dwelling, through which the upper loads are transmitted to the legs on the left and right sides of the cave-dwelling and then to the foundations. Therefore, it is a prerequisite to ensure the safety of cave dwellings by adopting a reasonable and accurate mechanical calculation model for the arch ring of a stone cave-dwelling to reveal the distribution of internal forces in the arch ring and scientifically design the arch ring accordingly. Three mechanical calculation models (structural calculation diagrams) are adopted for the arch ring of stone cave-dwelling, namely, hingeless arch, two-hinged arch, and three-hinged arch. Based on the force equilibrium and the force method from the structure mechanics, the formulae for calculating the internal force of the stone arch ring under these three different mechanical calculation models are derived respectively. The mechanical calculation results of three calculation models are compared and analyzed to clarify the difference and rationality of the stress results of the arch ring under the three mechanical calculation models and the degree of influence on the force of the lower cave-dwelling leg members. Lastly, in accordance with the internal force calculation results, the calculation formulae for the design of the arch ring thickness are proposed. The study shows that the hingeless arch and two-hinged arch models are more consistent with the actual failure characteristics, two-hinged arch calculation model is safer, more accu-rate, and more reliable than the hingeless arch calculation model when it is used in the mechanical analysis of circular arc arch ring. The findings are intended to serve as theoretical references for the design and construction, protection and reinforcement, and sustainable development and inheritance of cave dwellings in the future.

Conceptual Neutronics Study of a Hybrid Fusion Neutron Source FNS-C with Aqueous Blanket

The modern challenges of nuclear energy are the replenishment of dwindling reserves of nuclear fuel and the development of a closed nuclear fuel cycle while complying with strict radiation safety requirements. A fusion neutron source has unique capabilities to solve these problems. The preliminary results of a neutronic analysis of the FNS-C fusion-fission hybrid neutron source with a thorium-uranium aqueous blanket by the Monte Carlo method computer simulation, using the MCNP-4 code with the ENDF/B-VII cross-section library, gives satisfactory results for the study of the possibility of creating a compact source of fusion neutrons based on a small spherical tokamak for commercial use. The obtained results show that the FNS-C hybrid blanket generates enough tritium to fully ensure the uninterrupted operation of the FNS-C throughout the year. The reproduction coefficient of 233U is 1.027 at a consumption of 1304 kg/year of the fissile material in the aqueous blanket containing 232Th enriched to 1.47% 233U. The FNS-C is operated with an effective neutron multiplication factor keff ~ 0.99 with reactivity ρ = –0.006249 in the presence of delayed neutrons, which corresponds to the safest state of the core of thermal neutron fission reactors. The thermal power of the FNS-C at keff ~ 0.99 is ~3 GW, which is comparable to the thermal power of fission reactors. This indicates the potential possibility of creating a safe thorium-uranium breeder power reactor based on a fusion neutron source. The results of the study were obtained for the simplified approximate geometrical FNS-C model. To confirm the preliminary results, it is necessary to develop a more accurate calculation model of the FNS-C machine.

High accuracy and efficiency calculation model for predicting the reduction of residual stress on large pressure vessels by ultrasonic impact surface treatment

AbstractUltrasonic impact treatment (UIT) is a new surface strengthening method to reduce the residual stresses on large pressure vessels induced by surface and repair welding. An accurate and high efficiency calculation model is the key to accurately predicting the full‐field residual stresses on large pressure vessels under the UIT process. In this article, a full‐coverage impacting model is proposed to simulate the impacting process of the UIT pin. The effects of UIT on the residual stresses on repair and surface welded pressure vessels were investigated by explicit dynamic simulation. Experiments were also performed to verify the prediction results. Results show that the proposed full coverage impacting model can greatly improve the simulation precision and the calculation efficiency. The predicted residual stresses after the UIT process using the proposed model are consistent with the measured results. A remarkable reduction in residual stress was achieved in the zone subjected to UIT. The tensile residual stresses on the surface of the treated area were reduced to compressive stresses. With the increase of the impact velocity and the coverage rate, the residual stresses on the surface and transition layers decreased and then tended to stabilize. The impact coverage rate should not exceed 200% to avoid damage and save time.

An Accurate Dead Time Compensation Method for SPWM Voltage Source Inverters

Dead time is generally used to avoid the short circuit of the dc source, which causes harmonics in the output voltage and current of the voltage source inverters (VSIs). Based on an accurate harmonics calculation model of digital sinusoidal pulsewidth modulation, harmonics caused by dead time can be analyzed and calculated accurately. The proposed method obtains the compensation waveforms by the derived calculation module and detailed operation steps and then injects these into the sinusoidal reference voltage to eliminate the corresponding frequency harmonics caused by the dead time effect. The phase delay of the fundamental voltage caused by dead time is also considered. Moreover, this method avoids detecting the current polarity, affecting the compensation effect. Simulation and experimental results of the proposed method are presented to validate the effectiveness.

New Approach for Ampacity Calculation of Overhead Lines With Steel-Cored Conductors

Due to increasing energy demand and penetration of renewable energy sources into the grid, the transmission system has often been operated closer to its operating limit. This scenario requires the accurate calculation of the lines' ampacity in order to ensure their safe operation and the full use of their capacity. This paper proposes a new approach for calculating the ampacity of overhead lines with steel-cored conductors, using an accurate resistance calculation model in a straightforward way. The alternating current (AC) resistance of this type of conductors can be affected by the core magnetization depending on factors such as the number of aluminum layers and the core magnetic properties, which are properly considered using the proposed model. Results for the conductor AC resistance variation with the carried current value and the ampacity for different scenarios are presented and compared with those obtained using the resistance calculation models proposed in ampacity calculation methods by IEEE and CIGRE´ . Results show that the lines' ampacity tends to be underestimated using the existing models. However, for conductors with one aluminum layer, the IEEE method may overestimate the line's ampacity by considering a constant conductor resistance value, bringing risks of accidents due to conductor overheating.

Design and modeling of a novel triple-magnet magnetic dynamic vibration absorber

A novel Triple-magnet Magnetic Dynamic Vibration Absorber (TMDVA) with Eddy Current Damping (ECD) and Coulomb damping is proposed in this paper. A multi-storey structure is selected as the vibration reduction object. First, the equivalent dynamics model of the TMDVA multi-storey structure vibration reduction system is established. Then the nonlinear magnetic force model is built according to the magnetizing current theory. Next, an ECD accurate calculation model is developed and derived based on Faraday’s law of electromagnetic induction. Because of the model, the ECD coefficient can be designed and adjusted arbitrarily. The full text indicates that adjusting the ECD coefficient properly can not only improve the vibration reduction effect of the TMDVA, but also reduce the sensitivity of the vibration reduction effect to the excitation amplitude as well as enhance the broadband vibration reduction performance and the robustness of the TMDVA. With its simple structure, the TMDVA is easy to be implemented and miniaturized. And the low frequency vibration reduction effect of the TMDVA is better than other existing magnetic dynamic vibration absorbers. Taken together, the TMDVA has potential application value in passive vibration reduction of engineering structures.

Integrated Navigation Method of Aerospace Vehicle Based on Rank Statistics

The large dynamic and high-speed flight of aerospace vehicle will bring unpredictable conditions to its navigation system, resulting in that its system random noise probability distribution will no longer meet the preconditions of Gaussian distribution preset by the existing filter algorithm, thus reducing the accuracy of the navigation system. So, it is very important to propose an effective method to solve the filter problem of the navigation system in non-Gaussian distribution to improve the accuracy of the navigation system. Therefore, an integrated navigation method of aerospace vehicle based on rank statistics (LRF) has been proposed in this paper. Firstly, based on the flight characteristics of aerospace vehicles, an accurate gravity calculation model has been established to improve the accuracy of system modelling. Then, the state equation and measurement equation of integrated navigation system have been established. In combination with the rank filter algorithm as well as the determined weights, sampling points are calculated and nonlinearly propagated through the transition matrix to achieve an accurate estimation about the predicted values of the state quantities and measurement quantities and the covariance matrix. In turn, it simulates the probability distribution of the system state effectively. Therefore, when the system random noise probability distribution of the aerospace vehicle does not meet the Gaussian distribution due to various interference factors in the actual flight process, the algorithm can simulate the probability distribution of the actual system to the greatest extent, to improve the accuracy of the integrated navigation system and enhance the reliability of the navigation system ultimately.

Simplified loss calculation model for medium voltage modular multilevel converter

Modular multilevel converter (MMC) has broad application prospects in medium voltage scenarios such as DC distribution networks. Medium and low voltage MMC usually use carrier phase shift PWM (CPS-PWM), and the analytical formula of zero crossing point of MMC arm current considering double frequency circulating current component is complex, resulting in the existing MMC loss accurate calculation models are very complex and slow. To solve this problem, this paper proposes a simplified loss calculation model for MMC considering the equivalent of switching devices, which can easily, quickly and accurately calculate converter power losses under different operating conditions without and with circulation suppression, especially reveal the mathematical relationship between converter power losses and its double frequency circulation current component. Finally, based on actual engineering parameters, a comparative analysis of multiple operating conditions is carried out in the MATLAB/Simulink simulation, which verifies the correctness and accuracy of the proposed simplified loss calculation model.

Development of cross-section calculation module for high-temperature gas-cooled reactor engineering simulator system using an optimal model tree algorithm

To improve the accuracy of reactor physics module in the high-temperature gas-cooled reactor engineering simulator system (HTGR-ESS), a more accurate cross-section calculation model is required under the premise of real-time calculation in the simulation. Due to the nonlinear relationship between cross-section and reactor state parameters, such as burnup, moderator temperature and fuel temperature, etc., it is difficult to achieve full-range accuracy using the current multiple linear regression method (MLR). In this study, a machine-learning-based cross-section calculation model for the reactor physics model is proposed. We made improvements to the model tree by setting a smoothing function on the boundary and using ridge regression at the leaf node to conduct a continuous cross-section calculation model without overfitting in the subspace over the full range, trained from a scattered database generated by V.S.O.P. In the numerical tests, the proposed method produced far more accurate cross-section and reactor physics calculation results than the current method and could also meet the real-time calculation requirement. Meanwhile, the responses of the power and helium outlet temperatures of the 10 MW HTGR (HTR-10) simulator under different operating conditions conform to the reactor laws of physics, further validating the applicability of the proposed method.

Building height calculation for an urban area based on street view images and deep learning

AbstractThe building heights of an urban area are useful for space analysis, urban planning, and city management. To this end, a novel method for building height calculation for an urban area is proposed based on street view images and a deep learning model, that is, mask region‐based convolutional neural network (Mask R‐CNN). First, a spider of street view maps was developed, and an optimization model for observation locations was designed based on a genetic algorithm, by which the street view images of all buildings can be obtained with the minimum number of downloads. Subsequently, a deep learning workflow was designed based on the Mask R‐CNN to detect buildings from the panorama images. Finally, an accurate height calculation model considering repeated detection of buildings was developed by mapping between detected buildings and actual buildings. Case studies indicate that the mean error of height calculation is 0.78 m, which achieves high precision for calculating building heights in urban areas, while the average calculation time is 4.57 s per building, which indicates that the proposed method is efficient for the application in urban areas.