scholarly journals Applying the Heaviside step function to simulate the changes of temperature in automotive batteries

2021 ◽  
Vol 2061 (1) ◽  
pp. 012001
Author(s):  
N S Zakharov ◽  
N O Sapozhenkov ◽  
R V Tyan ◽  
V P Nazarov
Keyword(s):  
Thermal State ◽  
Electrical Equipment ◽  
Step Function ◽  
Heaviside Step Function ◽  
Large Cities ◽  
Battery Charge ◽  
Operating Modes ◽  
Control Units ◽  
Parking Lot ◽  
Nominal Capacity

Abstract Discharged batteries do not provide the specified voltage in the car’s power supply system during parking, which can cause malfunctions of electrical equipment and an increase in the quiescent current in the on-board network, due to incorrect operation of electronic control units responsible for the operation of self-diagnosis systems, anti-theft alarm, multi-media, maintaining a thermal state, etc. Therefore, to ensure a reliable start of the ICE and the proper operation of the electrical equipment of a car at low temperatures, it is required to maintain the battery in a charged state. Vehicle generator is selected taking into account the nominal capacity of the battery, power and operating modes of electrical consumers, which excludes the battery operation with a low level of charge. However, when operating cars in large cities in winter, the battery charge level decreases. Deterioration of the battery charging characteristics, increased power consumption of additional equipment and low speed of movement of cars in the city with frequent stops at intersections are the reasons for the decrease in the efficiency of the battery charge. In such conditions, the battery can be discharged not only by starting the ICE and turning on consumers in the parking lot, but also when the ICE is idling and at low crankshaft speeds while driving on city routes and during rush hours. Considering that the operational characteristics of the battery change significantly with decreasing temperature, studies aimed at establishing and predicting the battery temperature during operation are relevant.

A Meshless Local Petrov-Garlerkin Method for Solving the Biharmonic Equation

2014 ◽  
Vol 931-932 ◽  
pp. 1488-1494
Author(s):  
Supanut Kaewumpai ◽  
Suwon Tangmanee ◽  
Anirut Luadsong
Keyword(s):  
Relative Error ◽  
Biharmonic Equation ◽  
Interpolation Method ◽  
Step Function ◽  
Special Treatment ◽  
Maximum Relative Error ◽  
Heaviside Step Function ◽  
Treatment Techniques ◽  
Point Interpolation Method ◽  
Point Interpolation

A meshless local Petrov-Galerkin method (MLPG) using Heaviside step function as a test function for solving the biharmonic equation with subjected to boundary of the second kind is presented in this paper. Nodal shape function is constructed by the radial point interpolation method (RPIM) which holds the Kroneckers delta property. Two-field variables local weak forms are used in order to decompose the biharmonic equation into a couple of Poisson equations as well as impose straightforward boundary of the second kind, and no special treatment techniques are required. Selected engineering numerical examples using conventional nodal arrangement as well as polynomial basis choices are considered to demonstrate the applicability, the easiness, and the accuracy of the proposed method. This robust method gives quite accurate numerical results, implementing by maximum relative error and root mean square relative error.

scholarly journals AUTOMATION OF THE HEAT STATE ANALYSIS PROCESS HIGH-VOLTAGE CURRENT TRANSFORMERS

2019 ◽  
pp. 96-110
Author(s):  
V. M. Kutin ◽  
M. V. Nikitchuk ◽  
V. M. Svitko ◽  
O. O. Shpachuk
Keyword(s):  
Expert Knowledge ◽  
Thermal State ◽  
Statistical Processing ◽  
Electrical Equipment ◽  
Technical Condition ◽  
Mobile Systems ◽  
Electric Networks ◽  
Structural Element ◽  
Operating Life ◽  
Current Transformers

Thermographic control of electrical equipment allows you to draw preliminary conclusions about the technical condition of insulation, contact joints, windings, structural elements and cooling systems of electrical equipment of voltage classes 0.4 ÷ 750 kV. However, it should be borne in mind that the results of temperature measurement and assessment of the thermal state of electrical equipment are influenced by such factors as: environmental conditions, qualifications of personnel performing thermographic control and data interpretation, the need to improve regulatory documents for assessing the thermal state of electrical equipment and develop unified algorithms analysis of the results of thermographic examinations and gradation of the development of defects in electrical equipment. Modern research in the field of thermographic control of electrical equipment is developing in several directions, namely: the use of automated (stationary or mobile) systems for collecting thermographic data; development of algorithms for processing thermal images that reduce the influence of extraneous noise on the values of the measured temperatures, select the image of the object being examined, select the optimal level of contrast of the thermal image to detect thermal anomalies; using statistical processing of thermal fields of thermal monitoring objects and making decisions about the thermal state of equipment using neural networks, machine learning and expert knowledge. Automation of the analysis of thermographic control data is an urgent scientific and practical task, the solution of which will improve the quality of maintenance, repairs, extension of the operating life and operational management of electrical equipment in conditions of a significant level of aging of the main production assets of electric companies and change of generations of staff. Measuring current transformers of voltage classes 330 ÷ 750 kV are critical elements in the distribution schemes of electric power and in electric networks, and their technical condition directly affects the reliability of electric networks and power supply to consumers. The paper considers the reasons for the development of defects in current transformers of voltage classes 330 ÷ 750 kV, and also proposes relationships to take into account the influence of the air flow rate and the actual value of the emissivity of the structural element of the current transformers, as well as elements of the algorithms for analyzing data from thermal imaging surveys to reduce the influence of environmental factors and qualification level of the personnel performing the analysis, diagnostic results.

The Mesoscopic Investigation on Moduli Prediction in Visco-Elastic Particle Reinforced Composites

2008 ◽  
Vol 385-387 ◽  
pp. 329-332
Author(s):  
Xue Zhong Ding ◽  
Li Qiang Tang
Keyword(s):  
Volume Fraction ◽  
Step Function ◽  
Elastic Behavior ◽  
Loading Path ◽  
Elastic Model ◽  
Reinforced Composites ◽  
Heaviside Step Function ◽  
Equivalent Inclusion ◽  
Inclusion Theory ◽  
Elastic Particle

The visco-elastic mechanism of particles reinforced composites has been investigated through revised Eshelby equivalent inclusion theory. A visco-elastic model is applied. Furthermore, by introducing Heaviside step function and Laplace transform, the creep constitutional equation related to strain rate effect is achieved. Finally, by equivalent inclusion theory, introducing secant modulus, the material moduli with time and volume fraction concerning Glass/ED6 particles reinforced materials have been given. The results show that the visco-elastic property of composite material is mainly determined by the visco-elastic behavior of the matrix, which meet experiment results well. It can be concluded from the results that there exits close relationship between the inclusion shape, volume fraction and loading path.

scholarly journals An Asymptotic Approach for the Elastodynamic Problem of a Plate under Impact Loading

2010 ◽  
Vol 2010 ◽  
pp. 1-10
Author(s):  
Penelope Michalopoulou ◽  
George A. Papadopoulos
Keyword(s):  
Laplace Transform ◽  
Impact Loading ◽  
Step Function ◽  
Infinite Strip ◽  
Asymptotic Approach ◽  
Heaviside Step Function ◽  
Inertia Effects ◽  
Elastodynamic Problem ◽  
Line Force ◽  
The One

An approach is presented for analyzing the transient elastodynamic problem of a plate under an impact loading. The plate is considered to be in the form of a long strip under plane strain conditions. The loading is taken as a concentrated line force applied normal to the plate surface. It is assumed that this line force is suddenly applied and maintained thereafter (i.e., it is a Heaviside step function of time). Inertia effects are taken into consideration and the problem is treated exactly within the framework of elastodynamic theory. The approach is based on multiple Laplace transforms and on certain asymptotic arguments. In particular, the one-sided Laplace transform is applied to suppress time dependence and the two-sided Laplace transform to suppress the dependence upon a spatial variable (along the extent of the infinite strip). Exact inversions are then followed by invoking the asymptotic Tauber theorem and the Cagniard-deHoop technique. Various extensions of this basic analysis are also discussed.

scholarly journals Development of the methods of calculation of the electrical installations working operation in case of quality supply disturbance

2020 ◽  
Vol 7 (3) ◽  
pp. 140-155
Author(s):  
Ismael Saeed ◽  
◽  
Azad Mohammed
Keyword(s):  
Electrical Equipment ◽  
Equation System ◽  
Fault Current ◽  
Modes Of Operation ◽  
Operating Modes ◽  
Longitudinal Asymmetry ◽  
Methods Of Calculation ◽  
Short Circuits ◽  
The Mathematical Model ◽  
The Given

This paper proposes a method of calculating of asymmetrical modes of operation of electrical installations where simple and adequate loads equivalent circuits are available with working electrical equipment. So the mathematical model of equation system is derived as universal way for calculating the systems operating modes when it is subjected to a disturbance due to asymmetry. With the help of the obtained model we can calculate different cases of symmetry disturbances, all types of short circuits, between phase short circuits, any type of longitudinal asymmetry, open circuits when there is a resistance for the fault current at the place of damage In the given method, specific types of asymmetry are considered as particular cases and easily calculated from the generalized formula, which is essentially reduces the calculation and allows us to consider cases of asymmetry of any complexity. Therefore this method is offered as a basic for calculation of asymmetry when the system is subjected to a disturbance.

scholarly journals Characterization and Mitigation of Model Bias in Parametric Mapping of Dopamine Response to Behavioral Challenge

2021 ◽  
Author(s):  
Michael A Levine ◽  
Joseph B Mandeville ◽  
Finnegan Calabro ◽  
David Izquierdo-Garcia ◽  
Julie C Price ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Step Function ◽  
Binding Potential ◽  
Reference Tissue ◽  
Heaviside Step Function ◽  
Average Bias ◽  
Adult Participants ◽  
Single Target ◽  
First Pass ◽  
Initial Uptake

Compartmental modeling of 11C-raclopride (RAC) is commonly used to measure dopamine response to intra-scan behavioral tasks. Bias in estimates of binding potential (BPND) and its dynamic changes (ΔBPND) can arise when the selected compartmental model deviates from the underlying biology. In this work, we characterize the bias associated with assuming a single target compartment and propose a model for reducing this bias by selectively discounting the contribution of the initial uptake period. Methods: 69 healthy young adult participants were scanned using RAC PET/MR while simultaneously performing a rewarded behavioral task. BPND and ΔBPND were estimated using an extension of the Multilinear Reference Tissue Model (MRTM2) with the task challenge encoded as a Heaviside step function. Bias was estimated using simulations designed to match the acquired data and was reduced by introducing a new model (DE-MRTM2) that reduces the biasing influence of the initial uptake period in the modeled estimation of BPND for both simulations and participant data. Results: Bias in ΔBPND was observed to vary both spatially with BPND and with the assumed value of k4. At the most likely value of k4 (0.13 min-1), the average bias and the maximum voxel bias magnitude in the nucleus accumbens were estimated to be 1.2% and 3.9% respectively. Simulations estimated that debiasing the contribution of the first 27 minutes of acquired data reduced average bias and maximum voxel bias in the nucleus accumbens ΔBPND to -0.3% and 2.4% respectively. In the acquired participant data, DE-MRTM2 produced modest changes in the experimental estimates of striatal ΔBPND, while extrastriatal bias patterns were greatly reduced. DE-MRTM2 also considerably reduced the dependence of ΔBPND upon the first-pass selection of k2'. Conclusion: Selectively discounting the contribution of the initial uptake period can help mitigate BPND- and k4-dependent bias in single compartment models of ΔBPND, while also reducing the dependence of ΔBPND on the first-pass estimation of k2'.

scholarly journals Investigation of the Causes of Malfunctions of Special Electrical Equipment of Pumping Stations

2021 ◽  
Vol 12 (5) ◽  
pp. 1905-1910
Author(s):  
AyubjonVokhidov, Et. al.
Keyword(s):  
Voltage Drop ◽  
Stability Margin ◽  
Electrical Equipment ◽  
Static Stability ◽  
Technical Parameters ◽  
Operating Modes ◽  
Pumping Stations ◽  
Special Power ◽  
The Stability ◽  
Pumping Units

The task of this work was to consider the main technical parameters of pumping stations that affect the operating modes and the overall reliability of a special power supply system. Also, the technological processes of the irrigation pumping station were investigated and the analysis of mechanical and parametric characteristics, the causes of the asynchronous operation of mechanisms and the failure of the pumping units themselves was carried out. As a result of the work, a method for calculating the voltage drop was proposed, a new independent algorithm for calculating the static stability and the stability margin for the active power of special electrical equipment was developed.

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