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Journal articles on the topic 'Current calculations'

Author: Grafiati

Published: 30 May 2022

Last updated: 31 May 2022

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1

Mazur, Damian, and Marek Gołębiowski. "Calculating the main and leakage inductance matrix of the 3-column 15-winding autotransformer." Archives of Electrical Engineering 60, no. 3 (2011): 215–22. http://dx.doi.org/10.2478/v10171-011-0020-9.

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Calculating the main and leakage inductance matrix of the 3-column 15-winding autotransformer The aim of this paper is presentation and comparison of calculation methods of the inductance matrix of a 3-column multi-winding autotransformer. Main and leakage autotransformer inductance was obtained using finite elements method. Static calculations were made at the current supply for 2D and 3D models, and mono-harmonic calculations were made at the voltage supply. In the mono-harmonic calculations the eddy current losses were taken into account, this made it possible to study relationship between the autotransformer parameters and the frequency. Calculations were made using Ansys and the authors' own programs in Matlab.

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2

Sweeting, David. "Applying IEC 60909, Fault Current Calculations." IEEE Transactions on Industry Applications 48, no. 2 (2012): 575–80. http://dx.doi.org/10.1109/tia.2011.2180011.

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3

Dupuy, Delphine, David Pedreira, Damien Verbeke, et al. "Adaptive Meshing for Eddy Current Calculations." IEEE Transactions on Magnetics 51, no. 11 (2015): 1–4. http://dx.doi.org/10.1109/tmag.2015.2445830.

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4

Troisi, S., and L. Turturici. "NON-CURRENT EPHEMERIS FOR APPROXIMATED CALCULATIONS." Survey Review 30, no. 233 (1989): 135–39. http://dx.doi.org/10.1179/sre.1989.30.233.135.

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Komarzyniec, Grzegorz. "Calculating the Inrush Current of Superconducting Transformers." Energies 14, no. 20 (2021): 6714. http://dx.doi.org/10.3390/en14206714.

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Under certain circumstances, after connecting a superconducting transformer to the power network, a high value current may flow through its windings. This current can exceed the critical value of the superconductor many times and cause the windings to lose their superconductive state. Loss of superconductive state of the windings may result in thermal interruption of their continuity as a result of conduction of a current of very high density. The mathematical relationships used to calculate the inrush current of conventional transformers do not work well for the calculation of superconducting transformers. This is due to the properties of superconducting materials used in the windings, first of all to the stepwise changes of the windings’ resistance when exiting the superconducting state and when returning to this state. The article presents the mathematical dependencies allowing to calculate the pulse waveforms of the inrush current of these transformers are derived. Basic electrical circuit sizes are used in the calculations, making the calculations quick and easy. Using the formulas, calculations of the inrush current of 8.5 kVA and 13.5 kVA superconducting transformers. The results were verified with the results of the inrush current measurements, achieving good compliance.

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6

Stoneham, A. M. "Defect calculations in semiconductors Theoretical principles as illustrated by current calculations." Philosophical Magazine B 51, no. 2 (1985): 161–76. http://dx.doi.org/10.1080/13642818508240560.

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7

Golebiowski, Marek. "Calculation of eddy current and hysteresis losses during transient states in laminated magnetic circuits." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 36, no. 3 (2017): 665–82. http://dx.doi.org/10.1108/compel-09-2016-0409.

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Purpose The purpose of this paper is to develop the method of taking the eddy current losses in the laminated magnetic circuits into account during implicit transient calculations. The nonlinear magnetization characteristic of iron and the hysteresis losses can also be considered in the simulations done with the developed method. Design/methodology/approach The paper presents complex equivalent magnetic permeability derived from the presumed angular frequency in a laminated magnetic circuit. On this basis, the synthesis of a magnetic permeability as a function of the Laplace variable “s” is presented. After transformation of the variable “s” to a variable “z” of the Z transformation, it is possible to conduct discrete time calculation of transient states of magnetic circuits including the eddy current losses. An iterative process is developed to take the saturation of the magnetic circuit in these calculations into account. As regards hysteresis losses, the scalar model of magnetic hysteresis by Juhani Tellinen was implemented. The new method is validated by calculations of a two-coil transformer. Findings It is important to take into account the losses in sheet metal directly in the implicit transient calculations. This possibility is provided by the presented method based on the synthesis of the equivalent magnetic permeability μ^(s). The presented method was proved to be correct and efficient. The calculated sheet metal losses were compared with the results presented in literature. Good conformance of results was attained. Practical implications The method enables calculation of eddy current and hysteresis losses in laminated magnetic circuits during calculations of transient states. It does not need, unlike the previous methods, previously provided information (“a priori”) about the content of higher harmonics in waveforms. The method takes into account mutual dependence of transient waveforms of currents in the analysed system and losses of laminated magnetic circuit, expressed by eddy currents and hysteresis losses. Its implementation comes down to using in calculations a filter of the IIR type and corresponds to its calculation complexity. The author plans to use the presented method in the finite elements method transient calculations. Originality/value A new approach is a synthesis of the equivalent magnetic permeability in Laplace domain, which creates an equivalent RC circuit for permeability. Analytic equations for parameters of this equivalent circuit are original. A method for considering nonlinear magnetization characteristic and hysteresis losses was presented. In calculations of transient states of systems with magnetic circuits, one can use the developed equivalent circuit of magnetic permeability in a form of the IIR filter. Operator magnetic permeability includes fractional derivative of Laplace’s variable “vs”. Therefore, the equivalent IIR filter includes “history” of the processes that take place in the laminated magnetic circuit to the current, calculated time moment. This “history” in terms of its content is limited only by the degree of the applied IIR filter. It enables to calculate “step by step”, without previous (“a priori”) knowledge about harmonic components of the whole waveforms. It was necessary in the previously used methods, when determining parameters of magnetic permeability. The method proposed in the paper allows for calculations with taking into account direct dependence of an electric part of the system on its magnetic part.

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8

Fu, Pengwu, Dongwen Yang, Zhi He, Zhenfeng Duan, and Dengmei Wang. "Practical calculation of asymmetric short circuit current of DFIG connected to distribution network." E3S Web of Conferences 145 (2020): 02075. http://dx.doi.org/10.1051/e3sconf/202014502075.

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In view of the existing complex analytic calculations of DFIG short-circuit current are hardly applied in engineering projects, a practical calculation of asymmetric short-circuit current of DFIG is proposed. According to the complex sequence and their Thevenin equivalent model of DFIG network, the composition of each sequence component of DFIG short-circuit current is analysed. Moreover, considering the low-voltage ride through strategy of DFIG, the negative sequence periodic components of short circuit current are well analysed during the crowbar activation and deactivation, and the formula of the negative sequence periodic components of short circuit current are derived. On the basis of positive and negative sequence open circuit voltage, calculating impedance and rotor current, the judgement of crowbar activation is established. The pre-calculated surfaces of negative sequence periodic components of short circuit current are proposed, and the procedure for calculating the asymmetric short-circuit current of DFIG is designed. Finally, the proposed method is verified by simulation.

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9

Sato, Ken, Haruhiko Okumura, and Satarou Yamaguchi. "Numerical calculations for Peltier current lead designing." Cryogenics 41, no. 7 (2001): 497–503. http://dx.doi.org/10.1016/s0011-2275(01)00117-5.

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10

West, Alan C., Johannes H. Sukamto, and John Newman. "A Criterion to Verify Current Distribution Calculations." Journal of The Electrochemical Society 137, no. 9 (1990): 2745–52. http://dx.doi.org/10.1149/1.2087051.

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11

Khondker, A. N., and A. F. M. Anwar. "Approximate analytic current-voltage calculations for MODFETs." IEEE Transactions on Electron Devices 37, no. 1 (1990): 314–17. http://dx.doi.org/10.1109/16.43836.

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12

Nadtochy, P. N., C. Schmitt, and K. Mazurek. "On some limitations of current Langevin calculations." Physica Scripta T154 (May 1, 2013): 014004. http://dx.doi.org/10.1088/0031-8949/2013/t154/014004.

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13

Berizzi, A., A. Silvestri, D. Zaninelli, and S. Massucco. "Short-circuit current calculations for DC systems." IEEE Transactions on Industry Applications 32, no. 5 (1996): 990–97. http://dx.doi.org/10.1109/28.536856.

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14

Goolak, Sergey, Viktor Tkachenko, Svitlana Sapronova, Oleksandr Spivak, Ievgen Riabov, and Oleksandr Ostroverkh. "Determination of inductances for pulsating current traction motor." Technology audit and production reserves 2, no. 1(58) (2021): 40–43. http://dx.doi.org/10.15587/2706-5448.2021.229217.

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The object of research is a pulsating current traction motor. To improve the accuracy of its mathematical model, it is necessary to use the values of the parameters that are determined in experimental studies of the electric motor. In particular, it is important to use in the model of the electric motor inductance obtained experimentally. A method is proposed for calculating the inductance of the armature winding, main poles, additional poles and compensation winding and the total inductance of the traction motor armature circuit. The calculations are based on the results of the indirect inductance measurement method, in which the electrical values of various modes of power supply of the electric motor windings are directly measured, and the inductances are determined by auxiliary calculations. The inductances of the traction motor armature circuit have a non-linear dependence on the current flowing through them. The main difference of the study is that the measurements of the electrical parameters required for calculating the inductance are carried out over the entire range of operating currents of the windings. The essence of the proposed technique is to measure the active power in the armature winding, the winding of the main and additional poles, and the compensation winding, as well as in the armature circle as a whole when they are supplied with alternating current. According to the obtained values of active power losses and phase displacement, the corresponding reactive power losses are determined, with the help of which the inductances of the motor windings are calculated. Approbation of the methodology for calculating the conduction inductance for an electric motor of a pulsating current NB-418K6 (country of origin Russia), is used on electric locomotives of the VL80T and VL80k series (country of origin Russia). A scheme for measuring electrical parameters necessary for calculating inductance is proposed. The graphical dependences of the inductance on the armature current, built on the basis of calculations, confirmed the hypothesis about the nonlinear dependence of these inductances on the armature current. For further application of the results obtained in the simulation of the operation of the traction electric motor NB-418K6, a polynomial approximation of the total inductance of the armature circuit was performed.

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15

Castro, Luis Miguel, Daniel Guillen, and Frederic Trillaud. "On Short-Circuit Current Calculations Including Superconducting Fault Current Limiters (ScFCLs)." IEEE Transactions on Power Delivery 33, no. 5 (2018): 2513–23. http://dx.doi.org/10.1109/tpwrd.2018.2800732.

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16

Tarko, Rafał, Jakub Gajdzica, Wiesław Nowak, and Waldemar Szpyra. "Comparative Analysis of High-Voltage Power Line Models for Determining Short-Circuit Currents in Towers Earthing Systems." Energies 14, no. 16 (2021): 4729. http://dx.doi.org/10.3390/en14164729.

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The article deals with the problems of single-phase short-circuit current distribution in overhead power lines. Short-circuit disturbances cause many negative phenomena in power networks. Since experimental studies of short-circuits in real networks are practically impossible to perform, these effects can be evaluated only theoretically, based on short-circuit current calculations with the use of appropriate mathematical models. Although short-circuit modeling is considered to be one of the simplest power system calculations, the exact mathematical description of the phenomena occurring at short-circuits is complex. Simplified normative methods are often used for short-circuit current calculations; however, this does not give ground for a thorough analysis of short-circuit current distribution in power lines. The distributions are analyzed using power line models with different degrees of complexity in line with the assumptions made for a given model. The paper presents the problem of current distribution analysis in high-voltage overhead lines for single-phase faults to the tower structures. Simulation studies were conducted on the models developed for the calculation of short-circuit currents in the high-voltage power line earthing. The objective of the analysis was to assess the validity of simplification assumptions followed by practical recommendations on the applicability of the models.

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17

Shabanov, Vitalii, Albina Rakhimberdina, and Ilya Yanikiev. "ON THE ISSUE OF DETERMINING THE ELECTRICAL LOADS OF TRANSFORMER SUBSTATIONS." Electrical and data processing facilities and systems 18, no. 1 (2022): 114–22. http://dx.doi.org/10.17122/1999-5458-2022-18-1-114-122.

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Relevance The calculation of electrical loads is the basis for choosing the carrying capacity of all elements of the electrical network. An increase in rated loads compared to the necessary ones leads to cost overruns on power transmission lines and an increase in power of transformers, and a decrease in rated loads leads to increased power dissipation in networks, increased heating of conductors and transformers and increased thermal deterioration of their insulation. The reliability of the calculation of electrical loads depends both on the reliability of the calculation coefficients used and on the correctness of the methods used. Therefore, the research and improvement of the calculation of electrical loads in the design of power supply systems is an actual problem. Aim of research To investigate the determination of rated loads of transformer substations, methods of accounting for power dissipation in different modes of operation of the power supply system and methods for determining rated currents of cable lines to transformer substations. To consider the correctness of the use of standard forms for determining electrical loads recommended by regulatory documents. To develop a generalized form of performing calculations of electrical loads of transformer substations, combining the calculation of loads on the side of lower and higher voltages. Research methods To solve the tasks, the definition of electrical loads according to standard forms of regulatory documents is investigated. The methods of accounting for power dissipation in transformers under different operating modes of the power supply system and the determination of rated currents along cable lines to transformer substations are considered. Results The shortcomings of the execution and design of the calculation of electrical loads according to standard forms are revealed: standard forms do not contain information at which values of the heating time constant calculations are performed to determine the rated power of the electrical power load on the side of the lower and higher voltages of transformer substations, do not contain the definition of power dissipation in transformers. Ways of improving the calculation of electrical loads of transformer substations are proposed. A generalized form of execution and design of calculations of electrical loads of transformer substations have been developed, which include the values of time constants when calculating electrical power loads, the type and passport data of the selected transformer, calculations of power dissipation in transformers in two modes and calculations of the load current of cable lines to transformer substations.

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Żywicki, Jędrzej, Paweł Dymarski, Ewelina Ciba, and Czesław Dymarski. "Design of Structure of Tension Leg Platform for 6 MW Offshore Wind Turbine Based On Fem Analysis." Polish Maritime Research 24, s1 (2017): 230–41. http://dx.doi.org/10.1515/pomr-2017-0043.

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Abstract The article presents the calculation and design stages of the TLP platform serving as a supporting construction of a 6 MW offshore wind turbine. This platform is designed to anchor at sea at a depth of 60 m. The authors presented the method of parameterization and optimization of the hull geometry. For the two selected geometry variants, the load and motion calculations of the platform subjected to wind, wave and current under 50-year storm conditions were performed. The maximum load on the structure was determined in these extreme storm conditions. For these loads, the MES calculation of the designed platform was performed for the selected variant. Authors have presented a method for calculating maximum wind, wave and current stresses on the structure during the worst storm in the past 50 years. For these loads the MES endurance calculations of the designed platform were made. Based on the results of these calculations, the required structural changes and recalculations have been made in succession to the structural design of the platform, which meets the design requirements and has the required ad hoc strength. The article contains stress analysis in „difficult“ nodes of constructions and discusses ways of solving their problems. The work is part of the WIND-TU-PLA project from the NCBR Research Agreement (Agreement No. MARTECII / 1/2014).

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Krupová, Zuzana, Emil Krupa, Ludmila Zavadilová, Eva Kašná, and Eliska Žáková. "Current challenges for trait economic values in animal breeding." Czech Journal of Animal Science 65, No. 12 (2020): 454–62. http://dx.doi.org/10.17221/161/2020-cjas.

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Modern selection approaches are expected to bring about the cumulative and permanent improvement of animal performance and profitability of animal production. Breeding values of traits along with trait economic values (EVs) are utilised for economic selection purposes with many species all over the world. Currently, some challenges related to trait EVs in animal breeding should be considered. First, the selection response based on the higher accuracy of genomic selection may be reduced due to improper weighting of the trait breeding values of selection candidates. A comprehensive approach applied in bioeconomic models allows suitable trait EV calculations. Further challenges comprise the new breeding objectives associated with climate change, environmental mitigation and animal adaptability. The estimation of EVs for traits influencing greenhouse gas (GHG) emissions has been mostly based on including the value of CO<sub>2</sub> emission equivalent in the trait EVs, on calculating EVs for feed efficiency traits and on methane yield as a direct trait of GHG emission. Genetic improvement of production, functional, feed efficiency and methane traits through the application of multi-trait selection indices was found to be crucial for mitigation of emissions and farm profitability. Defining the non-market values of traits connected with climate protection could be a useful solution for including these traits in an economic breeding objective. While GHG emissions mostly change the costs per unit of production, animal adaptability in its complexity influences animal performance. Clear definitions of disease, fertility, mortality and other breeding objective traits allow the proper calculation of trait EVs, and an accurate estimation of trait genetic parameters could lead to sufficient economic selection response. This complex approach could be beneficial for more effective utilisation of inputs and overall economic and environmental sustainability of animal production.

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20

Bikeev, A., A. Kurchenkov, D. Shkarovsky, and V. Shkityr. "CALCULATION OF SELF-POWERED DETECTORS RESPONSE BY MEANS OF THE MCU-PD AND TVS-M CODES." PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. SERIES: NUCLEAR AND REACTOR CONSTANTS 2019, no. 4 (2019): 55–66. http://dx.doi.org/10.55176/2414-1038-2019-4-55-66.

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For successful licensing and safe passage of pilot operation of a new type of fuel in the core of an operating VVER-1000 reactor, it is necessary to carry out a preliminary validation of design codes that are routinely used for developing fuel cycles, core safety analysis and calculating maintenance of power unit operation. Validation matrix of the design codes includes problems of calculating transition functions of self-powered neutron detector (SPND). SPNDs are the part of incore monitoring system, which allows to determine power density in the core of an operating power unit. Transition functions from the self-powered detector current to the power density are calculated by means of TVS-M spectrum code. For each type of FA and each instance of self-powered detectors, transition functions are calculated in advance. Transition functions are never corrected during operation, therefore, strict requirements are imposed to the accuracy of their calculation. The main objective of the work is a comparative analysis of the TVS-M spectrum code and the MCU-PD Monte Carlo code as applied to the calculation of transition functions of self-powered neutron detectors for VVER fuel assemblies. During the work, we created calculation models of several types of fuel assemblies, differ in type of fuel, presence of fuel rods with Gd, and placement of SPND. We performed several series of calculations of the created FAs at different burnup steps. The calculations were carried out in states with different coolant parameters, fuel temperatures and presence of control rods. As the target functionals, we considered SPND current, SPND transition function and power density factor of six fuel rods surrounding SPND. We determined maximum relative deviations of TVS-M from MCU-PD in the target functionals calculation. We confirmed acceptable accuracy of calculations of the target functionals by means of TVS-M code for wide range of reactor parameters. We also estimated the influence of homogenization of the SPND structure on the accuracy of transition function calculation.

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21

He, Ren, and Donghai Hu. "Physical Mechanism of Eddy Current Demagnetizing Effect for Eddy Current Brake." Journal of Computational and Theoretical Nanoscience 13, no. 10 (2016): 6810–22. http://dx.doi.org/10.1166/jctn.2016.5632.

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This article researches both the mathematical relation between the braking force of eddy current brake and the speed of the moving conductor and the relationship between the average air-gap flux density and the velocity of the moving conductor respectively which result in the ambiguity of the physical mechanism of eddy current demagnetizing effect. The theoretical methods for obtaining the distribution of the excitation magnetic field, the eddy current magnetic field and the air gap magnetic field of eddy current brake were presented. Then the impacts of the excitation magnetic field and eddy current magnetic field on the distribution of air gap magnetic field were got through contrastive analysis and then the physical mechanism of eddy current demagnetizing effect is obtained. Finally, the influence of the eddy current demagnetizing effect on the design and control of eddy current brake was discussed in depth. The correctness of these theoretical calculations was validated by experiments on the retarder synthetic performance test bench or the finite element numerical calculation.

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22

Musiienko, Igor. "Automated calculation of road reinforced con-crete round culverts for operation in free-flow mode in program UKRRVS21." Bulletin of Kharkov National Automobile and Highway University, no. 93 (May 27, 2021): 112–17. http://dx.doi.org/10.30977/bul.2219-5548.2021.93.0.112.

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The modern approach to the design of road culverts involves the use of computeraided design (CAD). In design organizations of Ukraine software products of the Minsk company CREDO are being used for calculations of capacity of culverts by GRIS_T. Since 2019, the UKRRVS program is being developed to calculate culverts of road structures according to Ukrainian standards. At the moment, the program has the calculation of stormwater runoff according to MADI/SoyuzDorProekt formula and meltwater runoff (according the Road Handbook). In 2020, a new stage of automated calculation of road culverts started - calculations of capacity. The article presents the automated calculation of road reinforced concrete round culverts for pressureless operation. Goal. It is proposed to automate the calculation of road reinforced concrete round culverts for pressureless oper-ation. Methodology. The current methods for calculating the throughput of reinforced concrete road culverts have been used. Programming was carried out in the C# language using object-oriented programming. Results. The state of affairs in the auto-mation of hydraulic calculations in the road industry in accordance with Ukrainian standards was analyzed. It was concluded that at the moment the production uses the GRIS program of the CREDO company. The UKRRVS program is being developed. In this program, the issue of automating the calculation of the throughput of round culverts for operation in freeflow mode is relevant. The question of the methodology and algorithmization of this calculation, coding and interface support has been resolved. Practical value. The algorithm for calculating road culverts has been developed. A part of calculating the throughput of road culverts has been created in the UKRRVS program. This part covers the most com-mon group - round reinforced concrete culverts for freeflow operation. Originality. The interface has been created for the automation program for calculating road culverts. When you click the button “Round reinforced concrete pipes” in the main menu of the program UKRVS 21, the window “Calculation of a round reinforced concrete pipe operating in pressureless mode” opens. The calculation consists of three parts: the area of formation of initial data, the button “Calculate”, and the area of output of results of calculations. The area of formation of ini-tial data consists of 7 points. The area of the results of calculation of round reinforced concrete road cul-verts working in a pressureless mode consists of 14 points.

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23

GURYEV, A. P., and B. A. HAEK. "DETERMINATION OF THE FREE FLOW DEPTH UNDER UNEVEN CURRENT MODE IN PRISMATIC CHANNELS." Prirodoobustrojstvo, no. 4 (2020): 116–22. http://dx.doi.org/10.26897/1997-6011-2020-4-116-122.

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The aim of the work is to analyze the existing method of calculating the spillway from the depth of the free flow under uneven mode in prismatic channels with a slowly changing movement and to develop a method of calculations that allows applying it to any flows in a prismatic channel without using any special tables. The existing methods for calculating flow parameters are based on the use of the Chesy formula to determine the flow consumption with a slowly changing water movement. At the same time, there is a V.I. Charnomsky’s method of direct calculation of the flow parameters from the energy equation without limiting the value of the channel slope. The disadvantage of this method is a possibility to solve the energy equation by the method of sequential approximation since the flow energy equation includes two variables, the flow depth and the distance between the sections. To eliminate this difficulty, it is proposed to determine the distance between the depths that make up the geometric progression on the considered part of the channel which allows calculating parameters of the free fl ow surface for any channel slopes and hydraulic flow modes without to special tables.

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Zhang, Xu, and Wanbin Ren. "Modeling and Experimental Verification of Material Welding Characteristics for Low Current Switching Devices." Materials 13, no. 17 (2020): 3666. http://dx.doi.org/10.3390/ma13173666.

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Material welding failure considerably influences the electrical lifetime and reliability of low current switching devices. However, relevant studies on methods for calculating the threshold welding current and welding area under milli-Newton scale load forces are very limited. In this paper, the welding characteristics of metal material, including the threshold welding current, welding area and welding force are studied by using theoretical calculations and experiments. The comparison between the theoretical calculation and experimental results shows the accuracy of the built model. Further, the effects of mechanical load force and load current on welding force and welding area of representative metal materials are investigated. It is found that the anti-welding ability of metal materials depends not only on the exerted load force and current, but also the electrical resistivity, the thermal conductivity, the tensile strength, and the melting temperature of the materials.

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Pingak, Redi Kristian, Rosara Kolmate, and Bernandus Bernandus. "A Simple Matrix Approach to Determination of the Helium Atom Energies." Jurnal Penelitian Fisika dan Aplikasinya (JPFA) 9, no. 1 (2019): 10. http://dx.doi.org/10.26740/jpfa.v9n1.p10-21.

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Calculation of He atomic energy levels using the first order perturbation theory taught in the Basic Quantum Mechanics course has led to relatively large errors. To improve its accuracy, several methods have been developed but most of them are too complicated to be understood by undergraduate students. The purposes of this study are to apply a simple matrix method in calculating some of the lowest energy levels of He atom (1s2, triplet 1s2s, and singlet 1s2s states) and to reduce errors obtained from calculations using the standard perturbation theory. The convergence of solutions as a function of the number of bases is also examined. The calculation is done analytically for 3 bases and computationally with the number of bases using MATHEMATICA. First, the 2-electron wave function of the Helium atom is written as the multiplication of two He+ ion wave functions, which are then expanded into finite dimension bases. These bases are used to calculate the elements of the Hamiltonian matrix, which are then substituted back to the energy eigenvalue equation to determine the energy values of the system. Based on the calculation results, the error obtained for the He ground state energy using 3 bases is 2.51 %, smaller than the errors of the standard perturbation theory (5.28 %). Despite the fact that the error is still relatively large from the analytical calculations for singlet-triplet 1s2s energy splitting of He atom, this error is successfully reduced significantly as more bases were used in the numerical calculations. In particular, for n = 25, the current calculation error for all states is much smaller than the errors obtained from calculations using standard perturbation theory. In conclusion, the analytical calculations for the energy eigenvalue equation for the 3 lowest states of the Helium atom using 3 bases have been carried out. It was also found in this study that increasing the number of bases in our numerical calculations has significantly reduced the errors obtained from the analytical calculations.

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Villón-Béjar, Máximo. "HidroEsta, software for hydrological calculations." Revista Tecnología en Marcha 29, no. 5 (2016): 95. http://dx.doi.org/10.18845/tm.v29i5.2520.

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<p class="p1">This investigation, “HidroEsta, software for Hydrological Calculations” is oriented towards the creation of a computing tool using Visual Basic intended to facilitate and simplify difficult calculations that must be carried out in hydrological studies. </p><p class="p1">The software allows making calculations of statistical parameters, as well as linear and non-linear, simple and multiple regression calculations, and polynomial regressions. It is also useful for evaluating if a series of data can be fitted to a series of distributions, and calculating design events with a given probability of occurrence, based on a seasonal variation curve or a duration curve; analyzing a storm and calculating maximum intensities based on pluviograms data; calculating flow measurements taken with windmills or current meters; calculating maximum flows with empirical and statistical methods; calculating evapotranspiration and hydric balance. </p><p class="p1">Several numeric methods were used to solve the equations, selecting the most appropriate one for each case. The results of this work provide civil, agricultural engineers, and agronomists, hydrologists and other specialists who work in this field with a tool that enableZs them to carry out calculations, rapid simulations, and determine flow or precipitation for designs. </p>

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27

Musil, Luboš, Martin Tipka, Hana Hanzlová, and Jan Vodička. "Comparison of Methods for Crack Development State for Steel Fibre Reinforced Concrete." Solid State Phenomena 322 (August 9, 2021): 48–53. http://dx.doi.org/10.4028/www.scientific.net/ssp.322.48.

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Fibre reinforced concrete is a composite material that is increasingly used in construction practice. An often-discussed problem regarding the fibre reinforced concrete is the crack development state and post-cracking behaviour. The paper compares the calculations done according to the Eurocode design and calculations done according to the older procedure given by ČSN standard. The calculations are also compared with the calculations done using the SCIA Engineer software. From the obtained results, the complexity of the calculation, the amount of coefficients, and the variance of value given the current standards is evident.

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Demyaniushko, I. V., V. V. Mironova, and E. M. Loginov. "The current state of computational analysis methods of strength and reliability of vehicles wheels." Izvestiya MGTU MAMI 9, no. 2-4 (2015): 59–67. http://dx.doi.org/10.17816/2074-0530-67130.

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The review of modern approaches to the analysis of stress-strain state of motor vehicles wheels was made. It is shown that calculations of fatigue strength and resistance to impact are based on calculation of stress-strain state of wheel after bench loading using finite element method.

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Mariia Lutsyk. "CURRENT STATE OF CASH CIRCULATION AND CASHLESS CALCULATIONS." European Cooperation 2, no. 46 (2020): 41–54. http://dx.doi.org/10.32070/ec.v2i46.84.

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This study contributes to the scientific literature, emphasizing the urgency of the problem of withdrawal of funds from circulation, reducing cash turnover in the economies of different countries in order to minimize the risks associated with its use. Reducing cash flow is a task that requires solving economic, political, social, administrative, psychological problems. The general decrease in the volume of cash will lead to lower inflation, the risk of money laundering, terrorist financing, improve the investment climate, liberalize the credit market and more. Despite the rather long time during which the chosen topic is researched by scholars and studied in practice at the level of states, intergovernmental associations, banks, there is still a significant share of cash transactions with a general tendency to increase non-cash transactions both in number and amount. . Therefore, it is important to obtain and analyze relevant information, review forecasts, clarify plans, which is why this study is primarily devoted. The transition to non-cash payments is associated with a number of obstacles and challenges, so the author analyzes the determinants of implementation and the effectiveness of non-cash turnover substantiates which socio-economic factors constrain the use of non-cash transactions. The demand for the use of non-cash payments depends on the level of use of funds in the country, and on how quickly society will be able to give up physical money. The positive aspects of the impact of non-cash circulation on the country's economy, public administration, industry and society have been identified. Statistics show that the preference for certain types of payment instruments, cash or non-cash payment depends on the level of economic development of the country, traditions, habits and areas of economic activity in societies. This article considers and analyzes the current state of cash circulation in individual countries, the ratio of cash to total assets of global technology companies from 2007 to 2019; cash use forecasts in different countries are displayed. In addition, the issue of cybersecurity, which should be given special attention when it comes to payments using special means of payment in general, and on the Internet in particular, is not ignored.

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Mocak, Jan. "Voltammetric current–potential calculations using infinite series solution." Electrochemistry Communications 4, no. 10 (2002): 803–7. http://dx.doi.org/10.1016/s1388-2481(02)00449-6.

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Rapetti, F., Y. Maday, F. Bouillault, and A. Razek. "Eddy-current calculations in three-dimensional moving structures." IEEE Transactions on Magnetics 38, no. 2 (2002): 613–16. http://dx.doi.org/10.1109/20.996160.

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Fritz, Catherine O., Peter E. Morris, and Jennifer J. Richler. "Effect size estimates: Current use, calculations, and interpretation." Journal of Experimental Psychology: General 141, no. 1 (2012): 2–18. http://dx.doi.org/10.1037/a0024338.

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Decker, J., Y. Peysson, J. Hillairet, et al. "Calculations of lower hybrid current drive in ITER." Nuclear Fusion 51, no. 7 (2011): 073025. http://dx.doi.org/10.1088/0029-5515/51/7/073025.

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Netter, D., J. Leveque, P. Masson, and A. Rezzoug. "Monte Carlo Method for Transient Eddy-Current Calculations." IEEE Transactions on Magnetics 40, no. 6 (2004): 3450–56. http://dx.doi.org/10.1109/tmag.2004.831662.

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Hammond, P. "Upper and lower bounds in eddy-current calculations." IEE Proceedings A (Physical Science, Measurement and Instrumentation, Management and Education) 136, no. 4 (1989): 207–16. http://dx.doi.org/10.1049/ip-a-2.1989.0036.

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Crofton, J., and S. Sriram. "Reverse leakage current calculations for SiC Schottky contacts." IEEE Transactions on Electron Devices 43, no. 12 (1996): 2305–7. http://dx.doi.org/10.1109/16.544427.

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Liang, Y. Y., Y. X. Zhou, H. Chen, R. Note, H. Mizuseki, and Y. Kawazoe. "Current through single conjugated molecules: Calculations versus measurements." Journal of Chemical Physics 129, no. 2 (2008): 024901. http://dx.doi.org/10.1063/1.2951986.

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Bowler, J. R. "Eddy current calculations using half‐space Green’s functions." Journal of Applied Physics 61, no. 3 (1987): 833–39. http://dx.doi.org/10.1063/1.338131.

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39

Marushchenko, N. B., C. D. Beidler, and H. Maassberg. "Current Drive Calculations with an Advanced Adjoint Approach." Fusion Science and Technology 55, no. 2 (2009): 180–87. http://dx.doi.org/10.13182/fst55-180.

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40

Biro, O., and W. Maurer. "Transient 3D eddy current calculations in fusion reactors." IEEE Transactions on Magnetics 26, no. 5 (1990): 2364–66. http://dx.doi.org/10.1109/20.104732.

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Lee, M. E., S. I. Hariharan, and N. Ida. "Transient calculations of two-dimensional eddy current problems." IEEE Transactions on Magnetics 25, no. 4 (1989): 3140–44. http://dx.doi.org/10.1109/20.34387.

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Bowler, J. R. "Eddy current calculations using half-space Green's functions." NDT International 22, no. 3 (1989): 185. http://dx.doi.org/10.1016/0308-9126(89)90140-5.

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FERROGLIA, ANDREA. "QCD CORRECTIONS TO THE RADIATIVE DECAY $\bar{B}\to X_s\gamma$." Modern Physics Letters A 23, no. 37 (2008): 3123–40. http://dx.doi.org/10.1142/s021773230802879x.

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In this short review, the calculation of the next-to-next-to-leading order QCD corrections to the inclusive radiative decay [Formula: see text] is described. We summarize the salient features of the calculational framework adopted, discuss the results obtained in the last few years, and indicate the technical tools that made the NNLO calculations possible. We conclude by comparing the current NNLO theoretical estimate for the branching ratio with the experimental measurement and by briefly discussing the size and origin of the residual theoretical uncertainty.

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Zakrevsky, A. F. "Eddy current method for measuring the parameters of the test object." Electronics and Communications 16, no. 6 (2012): 11–15. http://dx.doi.org/10.20535/2312-1807.2011.16.6.240390.

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A mathematical model is presented eddy current sensor located above conductive half-space obtained by the discrete method. Based of such a model, the calculation formulas are given insertion impedance per turn and round flat coil, as well as their sensitivity to changes in the size of the gap. Using this model allows you to reduce time of electromagnetic analysis and calculation parameters of the eddy current sensor, to improve the accuracy of calculations in comparison with approximate methods. The proposed method implementation of a model for multi-parameter control using microcontrollers, which is considered by the example of determining the size of the gap

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ADAMS, J. P., and B. CASTEL. "QUASI-ELASTIC ELECTRON SCATTERING: CURRENT RESULTS, CURRENT PROBLEMS." International Journal of Modern Physics E 02, no. 04 (1993): 845–54. http://dx.doi.org/10.1142/s021830139300039x.

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We present a review of theories presently available for describing quasi-elastic electron scattering in both longitudinal and transverse channels. It is argued that calculations that limit their domain to the effects of nuclear structure in a nonrelativistic regime are capable of reconciling theory and experiment in the region of the peak of the quasi-elastic cross-section and thus to a large degree abrogate the need to consider more complex processes.

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Piekielny, Pawel, and Andrzej Waindok. "Using a Current Shunt for the Purpose of High-Current Pulse Measurement." Sensors 21, no. 5 (2021): 1835. http://dx.doi.org/10.3390/s21051835.

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Measurement of high-current pulses is crucial in some special applications, e.g., electrodynamic accelerators (EA) and converters. In such cases, the current shunts have limitations concerning the frequency bandwidth. To overcome the problem, a method based on the shunt mathematical model is proposed. In the method, the solution of ordinary differential equations for the RL circuit is carried out in order to obtain the real current shape. To check the method, as a referee, a Rogowski coil dedicated to measuring high-current pulses was used. Additionally, the measurement results were compared with the mathematical model of the tested power supply system. Measurements were made for the short power supply circuit, which allows eliminating the nonlinearity. The calculations were carried out using a circuit model. In order to obtain the parameters of the shunt (resistance and inductance), it was modeled using an ANSYS/Q3D Extractor software. Comparison of calculation and measurement results confirms the correctness of our method. In order to compare results, the normalized root mean square error (NRMSE) was used.

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Koteras, Dariusz. "Calculation of eddy current losses using the electrodynamic similarity laws." Archives of Electrical Engineering 63, no. 1 (2014): 107–14. http://dx.doi.org/10.2478/aee-2014-0008.

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Abstract The results of the eddy currents losses calculations with using electrodynamics scaling were presented in this paper. Scaling rules were used for obtain the values of the eddy currents losses. For the calculations Finite Element Method was used. Numerical calculations were verified by measurements and a good agreement was obtained

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Enescu, Diana, Pietro Colella, and Angela Russo. "Thermal Assessment of Power Cables and Impacts on Cable Current Rating: An Overview." Energies 13, no. 20 (2020): 5319. http://dx.doi.org/10.3390/en13205319.

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The conceptual assessment of the rating conditions of power cables was addressed over one century ago, with theories based on the physical and heat transfer properties of the power cable installed in a given medium. During the years, the evolution of the computational methods and technologies has made more powerful means for executing the calculations available. More detailed configurations have been analysed, also moving from the steady-state to dynamic rating assessment. The research is in progress, with recent advances obtained on both advanced models, extensive calculations from 2D and 3D finite element methods, simplified approaches aimed at reducing the computational burden, and dedicated solutions for specific types of cables and applications. This paper provides a general overview that links the fundamental concepts of heat transfer for the calculation of cable rating to the advanced solutions that have emerged in the last years.

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Gerasimov, Alexander, and Alexander Kirpichnikov. "Quasi-equilibrium channel model of an constant current arc." Thermal Science 7, no. 1 (2003): 101–8. http://dx.doi.org/10.2298/tsci0301101g.

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The rather simple method of calculation of electronic and gas temperature in the channel of arc of plasma generator is offered. This method is based on self-consistent two-temperature channel model of an electric arc. The method proposed enables to obtain radial allocation of gas and electronic temperatures in a non-conducting zone of an constant current arc, for prescribed parameters of discharge (current intensity and power of the discharge), with enough good precision. The results obtained can be used in model and engineering calculations to estimate gas and electronic temperatures in the channel of an arc plasma generator.

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Simic, Nikola, Luka Strezoski, and Boris Dumnic. "Short-Circuit Analysis of DER-Based Microgrids in Connected and Islanded Modes of Operation." Energies 14, no. 19 (2021): 6372. http://dx.doi.org/10.3390/en14196372.

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Since microgrids should be able to smoothly operate in two distinct modes—grid-connected and islanded, their fault currents can widely fluctuate depending on the operational mode. When the microgrid is connected to the grid, the highest fault current, by far, is supplied by the utility grid. In this mode, the fault current contribution from distributed energy resources (DERs) is less than 20%. However, when the microgrid switches to the islanded mode, the fault current contribution from the utility grid is lost and DERs are the sole fault current sources. Thus, the overall fault current in the islanded mode is multiple times lower when compared to the grid connected mode. Moreover, most of the DERs are inverter-based, with limited fault currents, which further reduces the overall fault current in the islanded mode. With the rapid rise of the microgrid penetration around the globe, this phenomenon can adversely influence the relay protection, and thus the microgrid fault current needs to be precisely analyzed. Therefore, the main purpose of this paper is to thoroughly analyze the fault current differences in two distinct operation modes of a microgrid, and to consequently derive conclusions regarding the required improvements in fault calculations and relay protection analysis in emerging microgrids. A representative microgrid test bed is developed and modelled using the in-house developed software as well as in a state-of-the-art hardware-in-the-loop environment. Several different short-circuit faults were simulated and analyzed in both grid-connected and islanded modes. The results show that the fault currents significantly differ depending on the operating mode, and thus highly influence the protection system. Moreover, test results show that the fault calculation algorithms aimed at radial distribution grids, mostly used for microgrid fault calculations in the available literature, need to be further improved to provide precise and time-efficient results when the emerging microgrids are considered. These results provide a valuable insight into the current state of the microgrids’ fault calculation and protection and reveal several important directions for future research.

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