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1
Katanaev, N. T., A. V. Lepeshkin, and A. F. Kolbasov. "Simulation of engine speed performance characteristics." Izvestiya MGTU MAMI 10, no. 1 (March 15, 2016): 28–30. http://dx.doi.org/10.17816/2074-0530-66920.
Повний текст джерелаАнотація:
The paper gives an overview of mathematical descriptions of engine speed performance characteristics that are needed when simulation of “engine-automobile-driver-environment” systems. The analysis of models based on different classes of functions is given; its advantages and disadvantages are discussed. The regression model based on the use of functions closely related to the physics of investigated processes is proposed.
2
Paliulis, Dainius. "Evaluation of Zinc Accumulation in Moss (Pylaisia polyantha) Growing Near Intensive Traffic Street Based on Modelling and Experimental Data." Rocznik Ochrona Środowiska 23 (2021): 198–213. http://dx.doi.org/10.54740/ros.2021.013.
Повний текст джерелаАнотація:
Pylaisia polyantha moss growing near intensive traffic in Geležinis Vilkas street at Vingis Park (Vilnius) was selected as an indicator of environmental pollution. Two models were applied for the study: the Gaussian plume model – for zinc emission from automobiles calculation and mathematical model – for recalculating the zinc emission from transport to zinc concentration in moss. Moss samples were collected during spring, summer and autumn. There were no significant changes in Zn concentrations between these periods. Zn emission dispersion from pollution source was calculated only for one vehicle, in order to reach relationships between environmental conditions and dispersion of Zn emission from vehicle exhaust fumes pipe. It was detected that the concentration of Zn tends to decrease with the distance from the pollution source. It was observed that there was a strong relationship between wind speed and Zn concentration – the slower the wind speed, the higher concentration of zinc in moss.
3
Satynarayana, Kosaraju, Are Swathi, Kesari Neeraja, Madipali Samaikhya, and Kumkuma Rajkiran. "Taguchi Optimisation In Machining EN18 Using Coated Tool Under Dry and MQL Condition." E3S Web of Conferences 184 (2020): 01013. http://dx.doi.org/10.1051/e3sconf/202018401013.
Повний текст джерелаАнотація:
Turning is one of the initial basic machining operation that prevails in assembly and production process. Modern techniques have been practices in rapid and eco-friendly production systems. Present study deals with the investigation of turning process on EN 18 steel which is been shown its existence in automobiles industries. Turning operation was performed using a coated tool insert with varying cutting speed (100, 125 and 150 mm/min), feed rate (0.05, 0.5, 0.15 mm/rev) and depth of cut (0.4, 0.8, 1.2 mm) at both dry and MQL conditions. The results obtained was compared to optimize the effect of minimum quality lubrication on surface roughness. Experimentally it was observed that speed of 100 m/min with combination of feed of 0.05 mm/rev and 0.4 mm depth of cut was found to be optimized for surface roughness in both the cases. The mathematical model generated for surface roughness and MRR for both dry and MQL turning models having better regression fit as it closer to 100. From ANOVA analysis feed was proved to be the highest contributing factor for surface roughness and for MRR speed is the most significant factor for both dry and MQL turning
4
Danilevičius, Algimantas, and Raimundas Junevičius. "VEHICLES' SAMPLE GENERATION AND REALIZATION IN CAR-FOLLOWING MATHEMATICAL MODELS / AUTOMOBILIŲ IMTIES GENERAVIMAS BEI REALIZAVIMAS SEKIMO PASKUI LYDERĮ MATEMATINIUOSE MODELIUOSE." Mokslas – Lietuvos ateitis 7, no. 5 (February 2, 2016): 564–70. http://dx.doi.org/10.3846/mla.2015.820.
Повний текст джерелаАнотація:
The object of the article is the adjustment of car-following mathematical models according to collected traffic data. Here the problem of ineffectively burdened road section is solved by adjusting the speed of vehicles in order to reduce the distance between the cars to a safe distance. The paper analyzes the car-following models to measure the interaction between vehicles in the same lane. Experimental data processed in Matlab and traffic distribution histograms are created using the most appropriate distribution curve. Distribution curve is used to compile congestion scenario of road section. Applicable model uses fundamental diagrams, which are created from the kind of traffic flow measurements. The mathematical model allows to choose the optimal vehicle speed while maintaining safe distance between vehicles, and to make recommendations to improve the traffic as the process. Straipsnio tyrimo objektas yra sukauptų automobilių srauto duomenų pritaikymas sekimo paskui lyderį matematiniuose modeliuose. Čia sprendžiama neefektyviai apkrautos kelio atkarpos problema. Siekiama sumažinti atstumą tarp automobilių iki saugaus atstumo, koreguojant automobilių greitį. Straipsnyje nagrinėjami sekimo paskui lyderį modeliai, pagal kuriuos įvertinama sąveika tarp toje pačioje eismo juostoje esančių transporto priemonių. Eksperimentiniai duomenys apdorojami taikant Matlab, sudaromos transporto srauto pasiskirstymo histogramos bei parenkama tinkamiausia skirstinio kreivė. Eksperimentinė skirstinio kreivė naudojama sudarant kelio atkarpos apkrovimo scenarijų – nustatoma modeliuojamos kelio atkarpos intensyvumo ir atstumų tarp transporto priemonių priklausomybė nuo laiko. Taikomame modelyje naudojamos fundamentalios diagramos, sudaromos pagal natūrinius eismo srauto matavimus. Matematinis modelis leidžia parinkti optimalų transporto priemonės greitį išlaikant saugų atstumą tarp transporto priemonių, taip pat juo remiantis galima teikti rekomendacijas, kaip gerinti automobilių eismą.
5
Zeng, Cheng, Dong Bo Yang, Li Liu, and Feng Tian Cai. "Modeling and Simulation Research on the Effect of Driving Skills on Vehicle Fuel Efficiency." Advanced Materials Research 512-515 (May 2012): 1167–73. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.1167.
Повний текст джерелаАнотація:
The research and application of eco-driving has the important practical significance for the energy conservation and emission reduction of automobile industry. In this paper, a simulation model has been set up based on GT-Suite and mathematical models of driving operations to simulate three typical driving operations. The results show that the acceleration speed plays important role in the acceleration operation. As the acceleration speed increases, fuel economy significantly deteriorates. In the transmission operation, the engine should not be operated in the high speed region. Otherwise, the fuel economy would deteriorate. In the cruise operation, the gear should be selected to matching the speed. High-gear low speed operation will cause safety problems, while low-gear high-speed operation will cause significantly deterioration of fuel economy.
6
Ilyanov, S. V., N. A. Kuzmin, and G. V. Borisov. "EXPERIMENTAL RESULTS OF FUEL CONSUMPTIONS CONSIDERING THE SPEEDS OF CITY BUSES." Intelligence. Innovations. Investment, no. 3 (2021): 72–80. http://dx.doi.org/10.25198/2077-7175-2021-3-72.
Повний текст джерелаАнотація:
At the moment, there is a large number of dissertations and scientific works covering the issues of traction-speed and fuel-economic characteristics of vehicles, the results of which are presented in the form of: regression models, approximating dependencies, mathematical models based on multivariate analysis, including a number of additional coefficients. In this connection, the use of the results of these works in practice is limited, since it requires high qualifications of the МTЕ personnel and the use of special software and hardware. At the same time, at the department “Automobile transport” NSTU named after R. E. Alekseev developed a probabilistic-analytical method for predicting fuel consumption by road trains, considering the high-speed mode of movement, which shows a high convergence of results with actual average speeds only for uniform movement of buses with a constant average speed, which is not applicable to the assessment of fuel consumption of city buses. Based on the hypothesis put forward on the applicability of the Weibull-Gnedenko distribution for calculating the average speeds of city buses and the normal distribution for calculating accelerations during movement, the tasks of this study are formulated, expressed in the development of mathematical models reflecting the dependences of speeds and accelerations during bus movement in urban operating conditions, for planning their fuel consumption. To solve the set tasks, the following experimental studies were carried out: determination of the average coefficient of total road resistance; the actual distribution of speeds and accelerations when driving city buses; determination of the average actual value of fuel consumption when the bus is moving and when idle at stopping points. Based on the results of processing experimental studies, the possibility of using the Weibull-Gnedenko law to describe the actual speeds in urban conditions and the normal law to describe accelerations when driving city buses was confirmed, which allows planning fuel consumption using the analytical apparatus of the theory of probability and mathematical statistics and using the developed methodology in practice of motor transport enterprises. Based on experimental studies and theoretical studies in this area, an analytical method for planning fuel consumption for city buses, considering the speed of their movement, has been developed, which allows planning fuel consumption without additional experiments. Carrying out such studies for other types of motor vehicles and assessing unaccounted for indicators of road, transport and natural-climatic operating conditions will create a generalized analytical method for planning fuel consumption by vehicles in various operating conditions.
7
Lee, Chih-Wei, Feng Tao, Yu-Yu Ma, and Hung-Lung Lin. "Development of Patent Technology Prediction Model Based on Machine Learning." Axioms 11, no. 6 (May 26, 2022): 253. http://dx.doi.org/10.3390/axioms11060253.
Повний текст джерелаАнотація:
Intellectual property rights have a great impact on the development of the automobile industry. Issues related to the timeliness of patent applications often arise, such as the inability of firms to predict new technologies and patents developed by peers. To find the proper direction of product development, the R&D departments of enterprises need to accurately predict the technology trends. Machine learning adopts calculation through a large amount of data through mathematical models and methods and finds the best solution at the fastest speed through repeated simulation and experiments, to provide decision makers with a reference basis. Therefore, this paper provides accurate forecasts through established models. In terms of the significance of management, the planning of future enterprise strategy can be divided into three stages as a short-term plan of 1–3 years, a medium-term plan of 3–5 years, and a long-term plan of 5–10 years. This study will give appropriate suggestions for the development of automobile industry technology.
8
Ibrar, A., S. Ahmad, A. Safdar, and N. Haroon. "Efficiency enhancement strategy implementation in hybrid electric vehicles using sliding mode control." Electrical Engineering & Electromechanics, no. 1 (January 4, 2023): 10–19. http://dx.doi.org/10.20998/2074-272x.2023.1.02.
Повний текст джерелаАнотація:
Introduction. Hybrid electric vehicles are offering the most economically viable choices in today's automotive industry, providing best solutions for a very high fuel economy and low rate of emissions. The rapid progress and development of this industry has prompted progress of human beings from primitive level to a very high industrial society where mobility used to be a fundamental need. However, the use of large number of automobiles is causing serious damage to our environment and human life. At present most of the vehicles are relying on burning of hydrocarbons in order to achieve power of propulsion to drive wheels. Therefore, there is a need to employ clean and efficient vehicles like hybrid electric vehicles. Unfortunately, earlier control strategies of series hybrid electric vehicle fail to include load disturbances during the vehicle operation and some of the variations of the nonlinear parameters (e.g. stator’s leakage inductance, resistance of winding etc.). The novelty of the proposed work is based on designing and implementing two robust sliding mode controllers (SMCs) on series hybrid electric vehicle to improve efficiency in terms of both speed and torque respectively. The basic idea is to let the engine operate only when necessary keeping in view the state of charge of battery. Purpose. In proposed scheme, both performance of engine and generator is being controlled, one sliding mode controllers is controlling engine speed and the other one is controlling generator torque, and results are then compared using 1-SMC and 2-SMC’s. Method. The series hybrid electric vehicle powertrain considered in this work consists of a battery bank and an engine-generator set which is referred to as the auxiliary power unit, traction motor, and power electronic circuits to drive the generator and traction motor. The general strategy is based on the operation of the engine in its optimal efficiency region by considering the battery state of charge. Results .Mathematical models of engine and generator were taken into consideration in order to design sliding mode controllers both for engine speed and generator torque control. Vehicle was being tested on standard cycle. Results proved that, instead of using only one controller for engine speed, much better results are achieved by simultaneously using two sliding mode controllers, one controlling engine speed and other controlling generator torque.
9
Shodiev, J., and M. Azimov. "Mathematical modeling of truck movement in rough road conditions of agricultural area." IOP Conference Series: Earth and Environmental Science 1076, no. 1 (August 1, 2022): 012003. http://dx.doi.org/10.1088/1755-1315/1076/1/012003.
Повний текст джерелаАнотація:
Abstract The article presents the methods of modeling the horizontal and vertical movement of a small truck Labo. Using the Lagrange equation of the second type, mathematical models of the movement of a small truck Labo on uneven roads developed. The mathematical models developed by the Runge-Kutta-number method solved and the values of the horizontal and vertical oscillations, speeds of movement and the forces acting and acting on each wheel of the automobile found. On the given masses, the parameters of the automobile’s leaf springs and the depreciation part are determined.
10
J, Santhakumar, and Mohammed Iqbal U. "Parametric Optimization of Trochoidal Step on Surface Roughness and Dish Angle in End Milling of AISID3 Steel Using Precise Measurements." Materials 12, no. 8 (April 24, 2019): 1335. http://dx.doi.org/10.3390/ma12081335.
Повний текст джерелаАнотація:
Tool steel play a vital role in modern manufacturing industries due to its excellent properties. AISI D3 is a cold work tool steel which possess high strength, more hardenability and good wear resistance properties. It has a wide variety of applications in automobile and tool and die making industries such as blanking and forming tools, high stressed cutting, deep drawing and press tools. The novel ways of machining these steels and finding out the optimum process parameters to yield good output is of practical importance in the field of research. This research work explores an attempt to identify the optimized process parameter combinations in end milling of AISI D3 steel to yield low surface roughness and maximum dish angle using trochoidal milling tool path, which is considered as a novelty in this study. 20 experimental trials based on face centered central composite design (CCD) of response surface methodology (RSM) were executed by varying the input process factors such as cutting speed, feed rate and trochoidal step. Analysis of variance (ANOVA) was adopted to study the significance of selected process parameters and its relative interactions on the performance measures. Desirability-based multiple objective optimization was performed and the mathematical models were developed for prediction purposes. The developed mathematical model was statistically significant with optimum conditions of cutting speed of 41m/min, feed rate of 120 mm/min and trochoidal step of 0.9 mm. It was also found that the deviation between the experimental and predicted values is 6.10% for surface roughness and 1.33% for dish angle, respectively.
11
Kiyashko, Larisa A., and Victoria A. Ksenofontova. "RESEARCH OF DEFORMATION AND DESTRUCTION OF CAR ELEMENTS UNDER EXTREME CONDITIONS." International Journal of Advanced Studies 12, no. 2 (June 30, 2022): 21–35. http://dx.doi.org/10.12731/2227-930x-2022-12-2-21-35.
Повний текст джерелаАнотація:
The article is devoted to the improvement of the methodology for the examination of the operation the vehicles in extreme conditions that occur during road traffic accidents (RTA). Of great interest in the field of road safety are the tasks of determining the causes of RTA and the conditions under which they occur. There are computer systems that allow modeling the processes of interaction automobile vehicles with obstacles and among themselves during an accident. These developments based on various mathematical models of the car collision process. The most reliable and promising are systems that based on methods for analyzing plastic deformations and destruction of car structural elements during an accident. The basis of these methods is the law of conservation energy or the model of the transition of the kinetic energy of a moving vehicle into the potential energy of a structure deformed after an accident. This process described with the help of the parameter – the energy equivalent of the speed. The analysis of the object is study – automobile body structures carried out. They classified as thin-walled shell structures that are easily plastically deformed. The available methods for solving the problems of analysis the elastic-plastic deformations in such structures do not allow providing the high accuracy of the solution necessary for the examination of the RTA.
Purpose – improvement of the methodology for conducting an autotechnical examination of an accident.
Methodology: solution of inverse problems of continuum mechanics.
Results: a variant of the finite element representation of the design and a method of the variational approach to determining the energy criteria of the process under study were developed. It provides the greatest accuracy in solving the tasks.
Practical implications: it is expedient to apply the obtained results when carrying out an autotechnical examination of an accident.
12
Dyakov, Ivan, and Olegas Prentkovskis. "OPTIMIZATION PROBLEMS IN DESIGNING AUTOMOBILES." TRANSPORT 23, no. 4 (December 31, 2008): 316–22. http://dx.doi.org/10.3846/1648-4142.2008.23.316-322.
Повний текст джерелаАнотація:
A mathematical model of optimization problems in designing automobiles is suggested and requirements raised are defined taking into account the main technical and economic characteristics of the automobile. The optimality criterion of the integral parts of the automobile is presented. The system approach to the theory of parametric optimization based on generalized models is used and the algorithm for solving the considered problem is offered.
13
Paryshev, Emil V. "Approximate mathematical models in high-speed hydrodynamics." Journal of Engineering Mathematics 55, no. 1-4 (July 26, 2006): 41–64. http://dx.doi.org/10.1007/s10665-005-9026-x.
Повний текст джерела
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Jose Andueza, Pedro. "Mathematical Models of Vehicular Speed on Mountain Roads." Transportation Research Record: Journal of the Transportation Research Board 1701, no. 1 (January 2000): 104–10. http://dx.doi.org/10.3141/1701-13.
Повний текст джерелаАнотація:
Mathematical models were developed to estimate vehicular speed on curves and tangents in mountain roads. The 85th percentile speed for curves was estimated by using the radius of the curve under consideration, the radius of the previous curve, sight distance in the curve, and tangent length before the curve. The average speed was calculated by using the radius of the curve under consideration, the radius of the previous curve, and sight distance. The 85th percentile and the average speed were estimated by using the radius of the previous curve and tangent length. Speeds adopted by drivers respond not to engineer’s design speed but to geometric characteristics of the road. A design procedure is proposed that takes advantage of available design speed and driver behavior on the road at the same time. On a curve, drivers consider two efficiency measures: speed and comfort. On some curves, they prefer to feel a certain degree of discomfort in exchange for obtaining greater speeds. For some geometric conditions, drivers adopt a speed that sacrifices not only comfort but also safety.
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Gmyrya, N. G., V. M. Sharipov, Y. S. Schetinin, A. V. Denisov, A. P. Marinkin, and E. E. Baulina. "Building of crawler transporters of extra light weight category on the basis of units and components of automobiles." Izvestiya MGTU MAMI 7, no. 2-1 (January 20, 2013): 23–33. http://dx.doi.org/10.17816/2074-0530-68114.
Повний текст джерелаАнотація:
The authors propose new schemes of steering mechanisms of tracked vehicles made on the basis of units and components of automobiles. The mathematical model of the steady turning of tracked vehicles with such steering mechanisms are developed as well as methods for calculating kinematic parameters, power and energy loading of the elements in the scheme taking into account the power losses in the transmission and suspension. The accuracy of the mathematical models is confirmed by the results of field tests of a tracked crawler "Vegus" with the proposed schemes of steering mechanisms.
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Khrulev, Oleksandr, Olexii Saraiev, and Iryna Saraieva. "The influence of centrial forces on crankshaft bearing lubrication is in emergency modes of the engine of the car." Journal of Mechanical Engineering and Transport 12, no. 2 (February 2021): 112–21. http://dx.doi.org/10.31649/2413-4503-2020-12-2-112-121.
Повний текст джерелаАнотація:
The analysis of the crankshaft bearing condition of the automotive internal combustion engines in the case of insufficiency and breakage of oil supply to them is carried out. It is noted that this fault is one of the most common causes of damage to rubbing pairs in operation. At the same time, the different groups of bearings are often damaged, which cannot be explained within the framework of existing models of plain bearing lubrication. The objective of the work is to develop a mathematical model of oil supply to connecting rod bearings in emergency mode, taking into account the characteristic features of the bearing design. The model also, depending on the nature of the damage, should help to determine and explain the causes of bearing failures if they occur in different modes when operating conditions are broken. A computational model has been developed that makes it possible to assess the effect of design differences in the features of oil supply and the action of the centrifugal forces during crankshaft rotation on the oil column in the lubrication hole where oil is supplied to the conrod bearing. Calculations of the change in time of the oil supply pressure to the connecting rod bearings for the various designs of the crankshaft lubrication holes have been performed. It is shown that, depending on the operating mode of the engine and its design, the oil pressure in front of the connecting rod bearings does not disappear immediately after oil supply failure to crankshaft. Moreover, the lower the crankshaft speed is, the longer the lubrication of the conrod bearings will continue. The calculation results are confirmed by the data of the expert studies of the engine technical condition, in which the crankshaft was wedged in the damaged main bearings was found in the absence of serious damage to the connecting rod ones. It has been found that such features of the damage correspond to an rapid breakage of the oil supply to the crankshaft in the case of such operational damage as the oil pump and pressure reducing valve failure, the oil filter seal and oil pan destruction, etc. The developed model explains the difference in lubrication conditions and in the damage feature to the main and connecting rod bearings in the emergency cases of the oil supply breakage, which are observed during operation, and helps to clarify the failure causes. This makes it possible to use the model and the obtained data when providing auto technical expert studies of the failure causes of automobile internal combustion engines This makes it possible to use the model and the obtained data when providing auto technical expert studies of the failure causes of automobile internal combustion engines when the operating conditions are broken.
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Ferreira, Moniki, Alexandre Santos, and Paulo Lucio. "Short-term forecast of wind speed through mathematical models." Energy Reports 5 (November 2019): 1172–84. http://dx.doi.org/10.1016/j.egyr.2019.05.007.
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Kulagin, V. A. "Development of a complex of mathematical models of a vehicle suspension for fatigue life analysis." Izvestiya MGTU MAMI 15, no. 4 (December 15, 2021): 33–42. http://dx.doi.org/10.31992/2074-0530-2021-50-4-33-42.
Повний текст джерелаАнотація:
The reduction in the duration of the development of new vehicles and the associated desire to reduce the costs of automotive plants contribute to a more active application of mathematical modeling to solve engineering problems. The tasks, which are analyzing and predicting the fatigue life of vehicle components and assemblies, can be solved using a set of methods and tools of mathematical modeling.
This article discusses the development of a complex of mathematical models of the front and rear suspensions of a passenger automobile, which have the properties necessary for accurate reproduction of wheel loads and dynamic behavior of the suspension as a mechanical system. The complex of mathematical models is implemented in a multi-link modeling environment. The models are designed to carry out a subsequent validation study of the loading of individual suspension components during forced service life tests. In the future, this complex of mathematical models can be used for simulation of semi-natural forced resource tests of the suspension module, as well as a sample for the development of suspension models of other automobiles.
The purpose of this work is to form sufficient requirements for mathematical models for the implementation of fatigue durability studies using mathematical modeling methods and obtaining reliable calculation results. Research engineers will be able to follow these requirements to determine and collect initial data for the development of their own mathematical models.
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Inaguma, Y. "Friction torque characteristics of an internal gear pump." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 225, no. 6 (April 11, 2011): 1523–34. http://dx.doi.org/10.1177/0954406211399659.
Повний текст джерелаАнотація:
This paper describes the influence of pump operating conditions, such as operating pressures, pump speeds, and oil temperatures, on the friction torque characteristics of internal gear pumps for automobiles. Additionally, it presents a new mathematical model reflecting the influence of the oil temperature on the friction torque. In an internal gear pump, the friction torque was affected by oil temperature as well as operating pressure and pump speed. When the operating pressure was high, the influence of oil temperature on friction torque at a pump speed of less than 1000 r/min was contrary to that at a pump speed of greater than 1000 r/min. It was considered that the friction torque is fundamentally composed of three components: the component dependent on the operating pressure, dependent on the pump speed, and independent of both the operating pressure and the pump speed. However, the component dependent on the operating pressure was affected significantly by not only the pump speed but also the oil temperature. In addition, another factor besides the viscosity of the oil existed in the component dependent on the pump speed. A mathematical model for the friction torque characteristic of the internal gear pump was newly established by adding factors including the oil temperature to the Wilson’s model. The new model was able to represent with accuracy the experimental friction torque characteristic in the internal gear pump under various pump operating conditions.
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Pavlov, V. D. "Mathematical models of resonance and antiresonance processes." Herald of the Ural State University of Railway Transport, no. 1 (2021): 17–27. http://dx.doi.org/10.20291/2079-0392-2021-1-17-27.
Повний текст джерелаАнотація:
The use of the symbolic (complex) method has significantly simplified the study of resonance and near-resonance phenomena, in particular, it has made it possible to deeply unify and formalize the consideration of various mechanical systems. The cumbersome and time-consuming operations associated with composing and solving differential equations have been replaced by simple algebraic transformations. The method is based on the mechanical analogue of Ohm’s law in a complex representation and the concept of mechanical reactance, resistance, impedance, susseptance, conductance and admittance. Resonances and antiresonances of forces and velocities are determined. Resonances occur when the elements are connected in parallel with a force source, or when the elements are connected in series with a velocity source. Antiresonances occur when a parallel connection and a speed source are combined, or a serial connection and a force source are combined. These concepts are a generalization to mechanics of the concepts of «voltage source» and «current source» from theoretical electrical engineering. The closest to the source of speed in its properties is a crank-rocker (connecting rod) mechanism with a massive flywheel. The source of force corresponds more to the rod of the significantly smaller of the two connected pneumatic cylinders.
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SHEINA, G. "Analysis of mathematical models of transmission lines." Journal of Electrical and power engineering 23, no. 2 (December 23, 2020): 16–19. http://dx.doi.org/10.31474/2074-2630-2020-2-16-19.
Повний текст джерелаАнотація:
This paper investigates a mathematical model of one elements of the power supply system - power transmission lines. The type of models depends on the initial simplifications, which in turn are determined by the complexity of the physics of processes. The task of improving the accuracy of modeling of emergency processes in the power system is due to the significant complexity of modern power systems and their equipment, high-speed relay protection, automation of emergency management and the introduction of higher-speed switching equipment. One of the reasons for a significant number of serious emergencies in the system is the lack of complete and reliable information for modeling modes in the design and operation of power systems. The development of a mathematical model of a three-phase power line, which provides adequate reflection of both normal and emergency processes, is relevant. The advanced mathematical model of power transmission lines allows to investigate various operational modes of electric networks. The improved mathematical model of the power transmission line reflects all the features of physical processes at state modes and transient process and provides sufficient accuracy of the results. The type of mathematical model of power transmission lines depends on the accepted simplifications, depending on the task of research. The purpose of this work is to analyze the mathematical model of the power transmission line to study the modes of operation of the power supply system, with the possibility of its application to take into account all the design features of overhead and cable power lines. The mathematical model of the power line for the study of the modes of operation of the power supply system is analyzed. It is used to take into account the design features of overhead and cable power lines, skin effect.
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Karelina, Maria Yu, Pavel I. Pospelov, Yuri V. Trofimenko, Alexey V. Terentyev, Alexander G. Tatashev, and Marina V. Yashina. "Mathematical models for traffic flows on highways with intersections and junctions." T-Comm 15, no. 11 (2021): 61–68. http://dx.doi.org/10.36724/2072-8735-2021-15-11-61-68.
Повний текст джерелаАнотація:
Mathematical models of motor traffic flow on highway sections on highway sections near intersections or flow segregation sections are considered. In these models, the particles corresponding to motor vehicles move according to probabilistic rules along a cellular field that moves at a constant speed in the direction coinciding with the direction of movement of the particles. A cell field consists of sequences of cells. Each such sequence corresponds to a lane on the highway. The time scale in the model is discrete or continuous. The model is a dynamic system with a discrete state space and discrete or continuous time. The mathematical description of the model can also be presented in terms of a cellular automaton or a random process with prohibitions. At any given time, there is no more than one particle in each cell. With each movement, the particle either moves one cell in the direction of movement, or moves to the next lane, or remains in place. The speed of the traffic flow on the highway section corresponds to the sum of the set speed of the cell field and the average speed of the particles relative to the field. The studied characteristics are the speed of the traffic flow, its intensity and the probability of successful rebuilding of the vehicle on the considered section of the highway. When setting the parameters of the model, data from measurements of the characteristics of traffic flows on highways are used. Analytical approaches have been developed to evaluate the studied characteristics. Computer programs have been created to implement the developed calculation algorithms. The results of calculations are given.
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Nigmatullin, S. M., and I. M. Shenderovskiy. "Mathematical models of electromechanics as an asymptotics of Maxwell-Minkowski equations." Izvestiya MGTU MAMI 9, no. 2-1 (January 20, 2015): 111–16. http://dx.doi.org/10.17816/2074-0530-67260.
Повний текст джерелаАнотація:
The article describes the methodological shortcomings of the standard formulation of the electrodynamics of moving material bodies: restriction of inertial motion of the bodies, the use of material relations in the form of linear equations with constant coefficients, absence of analytically correct transition to quasi-stationary electromagnetic processes. It is shown that these disadvantages can be overcome by using of experimental fact of absence of the electromagnetic field’s rest mass and applying the asymptotic expansions of the fields on the small parameters, which is the ratio of bodies’ speed to the light speed and the ratio of technical device sizes to the minimum length of the electromagnetic wave.
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Федонин, Олег, Oleg Fedonin, Светлана Степошина, and Svetlana Steposhina. "Definition of mathematical models for choosing the rational processing conditions SPD." Bulletin of Bryansk state technical university 2015, no. 2 (June 30, 2015): 82–87. http://dx.doi.org/10.12737/22909.
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Junevičius, Raimundas, Marijonas Bogdevičius, and Ádám Török. "MODELLING OF INTERNAL COMBUSTION ENGINES’ EMISSION THROUGH THE USE OF TRAFFIC FLOW MATHEMATICAL MODELS." TRANSPORT 26, no. 3 (October 5, 2011): 271–78. http://dx.doi.org/10.3846/16484142.2011.621978.
Повний текст джерелаАнотація:
Road traffic flows on a straight road segment are modelled in this article. The mathematical model of traffic flows has been constructed by using the method of lumped parameters. CO2, CO, CH, NOx, PM regression equations of internal combustion engines’ (ICE) emission has been developed. The accuracy of regression equations is 0.98÷0.99. The article presents assumptions for constructing the mathematical model, description of the mathematical model and gives simulation results. Traffic flow parameters, such as traffic flow concentration and traffic flow speed are presented as modelling results. ICE emission depending on the concentration and traffic flow speed are presented as well.
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Xu, Jin, Kui Yang, YiMing Shao, and GongYuan Lu. "An Experimental Study on Lateral Acceleration of Cars in Different Environments in Sichuan, Southwest China." Discrete Dynamics in Nature and Society 2015 (2015): 1–16. http://dx.doi.org/10.1155/2015/494130.
Повний текст джерелаАнотація:
In view of the tremendous improvements in the dynamic performance of automobiles and changes in the composition of drivers over the past several decades, it is valuable to examine the distribution of automobile’s lateral acceleration in new environments. The lateral accelerations, speeds, and trajectory curvatures of a passenger car on twelve highways with different design speeds and topographies were obtained. By synchronizing, matching, and counting, the distribution of the lateral acceleration was obtained, and the level of driving comfort was estimated. The10th,15th,50th,85th, and90thpercentile values of the lateral acceleration on three road types (six-lane road, four-lane road, and two-lane road) were found. Combined with scatter diagrams of the lateral acceleration over the curvature, the negative correlation between the lateral acceleration and the curvature was analyzed and interpreted. In addition, regression models of the lateral acceleration with the curvature for the three kinds of roads were established. Based on scatter diagrams of the lateral acceleration over the speed, regression models of the averageaydepending on the speed and the85thpercentileaydepending on the speed of passenger cars and buses were established. The research provides calculation parameters and a control basis for operating speed prediction, pavement material design, and maximum and minimum limit value determination for the superelevation ratios and curve radii.
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Dolling, David S. "High-Speed Turbulent Separated Flows: Consistency of Mathematical Models and Flow Physics." AIAA Journal 36, no. 5 (May 1998): 725–32. http://dx.doi.org/10.2514/2.460.
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Dolling, David S. "High-speed turbulent separated flows - Consistency of mathematical models and flow physics." AIAA Journal 36 (January 1998): 725–32. http://dx.doi.org/10.2514/3.13885.
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Sukharev, R. Yu. "Mathematical models of wheel turning processes road construction vehicles." Nauchno-tekhnicheskiy vestnik Bryanskogo gosudarstvennogo universiteta 7, no. 3 (September 25, 2021): 259–69. http://dx.doi.org/10.22281/2413-9920-2021-07-03-259-269.
Повний текст джерелаАнотація:
The construction of highways is a complex, multi-stage process. Most of the construction works are carried out according to the projects of structures and quite high requirements are imposed on the quality of execution. The fulfillment of these requirements is associated with great difficulties in view of the limited accuracy of the road construction machine itself, the lack of on-board control systems and the limited capabilities of the human operator, who is unable to determine the required exact parameters of the structure being built «by eye». To meet the requirements, three-dimensional control systems are used, which allow determining 3 coordinates of the working order of the machine – the vertical coordinate and the location of the machine on the construction site. At the same time, the digital project of the constructed structure should be the setter in such a system. The system determines the current position and compares it with the project. On the basis of this information, a control effect on the operating organ of the machine is formed. The course of movement and the speed of the machine when using such systems are determined by the machine operator. Further development of these systems should be four-dimensional systems – in which all control actions are assigned to the control system, starting from calculating the trajectory of the machine, choosing the speed, determining the required number of passes and ending with controlling the position of the working body of the machine at each moment of time. For the functioning of these systems, adequate mathematical models of the turning processes of road construction machines with different steering options are necessary.
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Xiao, Zhengming, Jinxin Cao, and Yinxin Yu. "Mathematical Modeling and Dynamic Analysis of Planetary Gears System with Time-Varying Parameters." Mathematical Problems in Engineering 2020 (March 16, 2020): 1–9. http://dx.doi.org/10.1155/2020/3185624.
Повний текст джерелаАнотація:
Planetary gears are widely used in automobiles, helicopters, heavy machinery, etc., due to the high speed reductions in compact spaces; however, the gear fault and early damage induced by the vibration of planetary gears remains a key concern. The time-varying parameters have a vital influence on dynamic performance and reliability of the gearbox. An analytical model is proposed to investigate the effect of gear tooth crack on the gear mesh stiffness, and then the dynamical model of the planetary gears with time-varying parameters is established. The natural characteristics of the transmission system are calculated, and the dynamic responses of transmission components, as well as dynamic meshing force of each pair of gear are investigated based on varying internal excitations induced by time-varying parameters and tooth root crack. The effects of gear tooth root crack size on the planetary gear dynamics are simulated, and the mapping rules between damage degree and gear dynamics are revealed. In order to verify the theoretical model and simulation results, the planetary gear test rig was built by assembling faulty and healthy gear separately. The failure mechanism and dynamic characteristics of the planetary gears with tooth root crack are clarified by comparing the analytical results and experimental data.
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Biktasheva, I. V., R. D. Simitev, R. Suckley, and V. N. Biktashev. "Asymptotic properties of mathematical models of excitability." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, no. 1842 (March 21, 2006): 1283–98. http://dx.doi.org/10.1098/rsta.2006.1770.
Повний текст джерелаАнотація:
We analyse small parameters in selected models of biological excitability, including Hodgkin–Huxley (Hodgkin & Huxley 1952 J. Physiol. 117 , 500–544) model of nerve axon, Noble (Noble 1962 J. Physiol. 160 , 317–352) model of heart Purkinje fibres and Courtemanche et al . (Courtemanche et al . 1998 Am. J. Physiol. 275 , H301–H321) model of human atrial cells. Some of the small parameters are responsible for differences in the characteristic time-scales of dynamic variables, as in the traditional singular perturbation approaches. Others appear in a way which makes the standard approaches inapplicable. We apply this analysis to study the behaviour of fronts of excitation waves in spatially extended cardiac models. Suppressing the excitability of the tissue leads to a decrease in the propagation speed, but only to a certain limit; further suppression blocks active propagation and leads to a passive diffusive spread of voltage. Such a dissipation may happen if a front propagates into a tissue recovering after a previous wave, e.g. re-entry. A dissipated front does not recover even when the excitability restores. This has no analogy in FitzHugh–Nagumo model and its variants, where fronts can stop and then start again. In two spatial dimensions, dissipation accounts for breakups and self-termination of re-entrant waves in excitable media with Courtemanche et al . kinetics.
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Micklem, J. D., D. K. Longmore, and C. R. Burrows. "Modelling of the Steel Pushing V-Belt Continuously Variable Transmission." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 208, no. 1 (January 1994): 13–27. http://dx.doi.org/10.1243/pime_proc_1994_208_094_02.
Повний текст джерелаАнотація:
The steel pushing V-belt continuously variable transmission (CVT) is now commercially available in the automobiles of a number of manufacturers but to date it has not led to a significant reduction in fuel consumption. To develop its full potential it is necessary to have a good mathematical model of the system. A number of models have been described in recent years but all make use of a Coulomb friction model for the shear connection between the belt and the pulleys. This paper proposes a friction model based on elastohydrodynamic theory. It is shown that there is good agreement between measured and calculated slip values for the transmission which justifies use of the model.
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Huang, Shi Feng, Feng Wang, Hui Xu, and Xiao Xian Wei. "Research on Optimal Operation of Raw Water Pumping System Based on Hydromechanics in Waterworks." Applied Mechanics and Materials 327 (June 2013): 294–300. http://dx.doi.org/10.4028/www.scientific.net/amm.327.294.
Повний текст джерелаАнотація:
According to the raw water pumping system with constant speed pump and variable speed pumps based on hydromechanics in waterworks, the hydraulic simulation models were built including pump station, water tanks, suction well etc. Based on the analysis of objective function and constraints of water treatment structures and consideration of pump operation and initial water level of clean-water-tank, the compact optimal operation mathematical models were built. Finally, correctness and advantage of the mathematical models were proved by the optimal simulation of Jinshan water supply project, which provided the valuable reference for the energy-saving operation of raw water pumping system.
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Wu, Lan, Qi Shen, and Gen Li. "Identifying Risk Factors for Autos and Trucks on Highway-Railroad Grade Crossings Based on Mixed Logit Model." International Journal of Environmental Research and Public Health 19, no. 22 (November 16, 2022): 15075. http://dx.doi.org/10.3390/ijerph192215075.
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This study aimed to determine different influencing factors associated with the injury outcomes of heavy vehicle and automobile drivers at highway–rail grade crossings (HRGCs). A mixed logit model was adopted using the Federal Railroad Administration (FRA) dataset (n = 194,385 for 2011–2020). The results show that drivers’ injury severities at HRGCs are enormously different between automobile and truck/truck–trailer drivers. It was found that vehicle speed and train speed significantly affect the injury severity in automobile and truck drivers. Driver characteristics such as gender and driver actions significantly impact the injury severity in automobile drivers, while HRGC attributes such as open space, rural areas, and type of warning device become significant factors in truck models. This study gives us a better understanding of the differences in the types of determinants between automobiles and trucks and their implications on differentiated policies for car and truck drivers.
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Alexander, R. McNeill. "Simple Models of Human Locomotion." Journal of Theoretical Medicine 1, no. 2 (1997): 129–35. http://dx.doi.org/10.1080/10273669708833013.
Повний текст джерелаАнотація:
The human body is a complex structure, but our understanding of its movements is greately enhanced by extremely simple mathematical models. A model of walking shows why we have to break into a run at speeds above 3 meters per second, and why the critical speed is lower for children and on the moon. A model of running jumps show why long jumpers run up at a fast sprinting speed, but high jumpers run up much more slowly. Finally, a model od standing jumps explains why athletes can jump higher by using a countermovement than from a static squatting position. The body is represented in these models as a small number of rigid segments connected by hinge joints, powered by muscles with realistic physiological properties.
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Zhang, Yiqi, and Changxu Wu. "Learn to Integrate Mathematical Models in Human Performance Modeling." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 61, no. 1 (September 2017): 776–80. http://dx.doi.org/10.1177/1541931213601678.
Повний текст джерелаАнотація:
The current paper provided a tutorial of the integration of mathematical models in human performance modeling. It introduced the unique features of mathematical modeling in human performance, and the steps in mathematical model integration, including how the literature of models was reviewed, how a research gap was identified, and how a mathematical model was developed and integrated based on existing models, and how a model was validated via an experimental study. A case study was presented by following each step to illustrate the integration of several existing models to derive a new model of drivers’ braking performance in warning response with its integration with the existing mathematical models of driver speed control in normal situations and the model of humans’ warning response time. This is the first tutorial work that provided a detailed explanation of the steps in mathematical model integration with a case study in human performance modeling. It could be used as guidance for human factors professionals to learn the mathematical modeling approaches and will benefit the field of human performance modeling.
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Gorobtsov, A. S., M. V. Lyashenko, N. S. Sokolov-Dobrev, V. V. Shekhovtsov, P. V. Potapov, E. V. Klementyev, and A. A. Dolotov. "Mathematical model of test bench." Izvestiya MGTU MAMI 10, no. 2 (June 15, 2016): 20–25. http://dx.doi.org/10.17816/2074-0530-66903.
Повний текст джерелаАнотація:
The description of multifunctional test bench construction to determine the basic operational characteristics of transmissions of automobiles and trucks designed in Volgograd State Technical University is provided. The description of its mathematical model created on the basis of the spatial dynamic schema is given and the results of calculation of test bench mass and inertia parameters are provided. The models of moving masses are the masses of transmission rotating elements, which transmit torque, transmission housing, test bench frame, that consists of two subframes, two hubs, DinaPack loading device, including a hydraulic machine. The values of parts inertia moments and stiffness of its joints are obtained by DASP software package and SolidWorks 3D CAD system. On the first stage to carry out the simulation capabilities at various loading conditions and forecast their results without a long-term field tests, on the basis of the structural scheme of test bench the flat dynamic model was created, which besides the data on composition and communication of the masses, contains data on elastic, inertial and dissipative parameters of its elements. On the next stage the spatial structural test bench scheme was created, on the basis of which in “Universal mechanism” program the spatial dynamic model was made. The dynamic model of test bench includes 31 inertial masses influenced by linear, contact, bipolar and special forces. To check the adequacy of the created model at the initial stage the calculation of fundamental frequencies of its masses in the range from 0 to 10000 Hz was made. The comparison of its values with the results of processing of experimental digital oscillograms of test bench masses oscillations showed sufficient for the solution of engineering problems convergence of results.
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Ciupan, Cornel, A. Pop, and Liviu Morar. "The Mathematical Model of Abrasive Waterjet Milling Process." Advanced Materials Research 23 (October 2007): 187–90. http://dx.doi.org/10.4028/www.scientific.net/amr.23.187.
Повний текст джерелаАнотація:
The paper presents the mathematical model of abrasive waterjet milling process. Based on analysis of existing models the authors realize a new mathematical model, considering some simplifying hypothesis. This model uses output data from model [1] and determines the advance speed, the consumption of the abrasive and the productivity of the process. To establish the productivity of the process and the advance speed we’ll use the “energy preservation” model. This model takes in account the material characteristics. The mathematical model has been solved numerical and the results have been interpreted.
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Junevičius, Raimundas, and Marijonas Bogdevičius. "MATHEMATICAL MODELLING OF NETWORK TRAFFIC FLOW." TRANSPORT 24, no. 4 (December 31, 2009): 333–38. http://dx.doi.org/10.3846/1648-4142.2009.24.333-338.
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The article describes mathematical models of traffic flows to initiate different traffic flow processes. Separate elements of traffic flow models are made in a way to be connected together to get a single complex model. A model of straight road with different boundary conditions is presented as a separate part of the network traffic flow model. First testing is conducted in case the final point of the whole modelled traffic line is closed and no output from that point is possible. The second test is performed when a constant value of traffic flow speed and traffic flow rate is entered. Mathematical simulation is carried out and the obtained results are listed.
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Du, S. X., D. A. Hudson, W. G. Price, and P. Temarel. "A validation study on mathematical models of speed and frequency dependence in seakeeping." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 214, no. 1 (January 1, 2000): 181–202. http://dx.doi.org/10.1243/0954406001522903.
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An extensive theoretical validation exercise is presented into the speed and frequency dependent solutions associated with surface piercing vessels travelling in waves. The basis of the study lies in the formulation of the Green's function satisfying the traditionally posed linearized boundary value problem of an oscillating ship with forward speed and the development/implementation of appropriate numerical schemes of study for solution. Two widely different mathematical models in formulation and numerical algorithm, denoted as methods A and B, are discussed and employed to predict hydrodynamic coefficients, wave loads and responses of a Series 60 form and an NPL monohull. Only a selection of results are shown, but great care was taken in the overall investigation to verify and validate intermediate steps within the separate calculation procedures as well as to compare final predicted values. The extensive qualitative and quantitative agreement of comparable results from methods A and B provides a measure of confidence that the presented findings are solutions to the posed seakeeping problem. The influence of speed and frequency dependence within the context of this study are discussed as well as a preliminary study into their influence in the occurrence of irregular frequencies in the numerical schemes.
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Wei, Weihua, Yuantong Li, Tongming Xue, Xiao Liu, Long Chen, Jian Wang, Tongyue Wang, and Yaning Cai. "Research on milling forces during high-speed milling of wood-plastic composites." BioResources 14, no. 1 (December 6, 2018): 769–79. http://dx.doi.org/10.15376/biores.14.1.769-779.
Повний текст джерелаАнотація:
To analyze the influence of the milling parameters, including the spindle speed, feed rate, axial cutting depth, and radial cutting depth, on the milling force during high-speed milling of wood-plastic composites, an orthogonal test was performed with carbide cutting tools. The results showed that the tangential (Fx) and radial forces (Fy) decreased with an increase in the spindle speed, increased with an increase in the feed rate, and increased with an increase in the axial milling depth. Also, both were influenced by a relatively small amount of change in the axial milling depth. Mathematical models of Fx and Fy during the high-speed milling of wood-plastic composites were established with a multiple linear regression method. The variance analysis showed that the two mathematical models of the milling forces were significant overall.
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Hermawan, Karina, and Diem-Trinh Le. "Examining Factors Influencing the Use of Shared Electric Scooters." Sustainability 14, no. 22 (November 14, 2022): 15066. http://dx.doi.org/10.3390/su142215066.
Повний текст джерелаАнотація:
Shared e-scooters have the potential to increase access, complement transit, and replace automobiles, all while reducing emissions and congestion. However, there are concerns worldwide over the mode’s safety issues and risks. In this paper, we explore both the motivations and barriers to using e-scooters. Data are collected from a stated preference survey, using a sample consisting of mostly university staff and students in Singapore. Three logit models with varying specifications of e-scooters’ speed and lane use and one’s prior experience of conflict with a personal mobility device (PMD) are estimated. Overall, the three models have a very comparable fit (adjusted R2 of about 0.55) and consistent results. The results indicate preferences for e-scooters if they are faster and off the sidewalk. However, a bad or unsafe experience with a PMD would negatively affect use to a greater degree, although it varies across individuals. Our study suggests diverting scooters off the sidewalk and increasing the speed may not always be effective in encouraging behavioral shifts toward this alternative mode. Other solutions such as improving the services and enhancing traffic safety should be explored and considered instead.
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Rong, Jun, Yue Jiao Ding, Xi Chen, Li Wan, and Yi Ming Li. "Modeling and Simulation of Voltage Frequency Ratio Control System for Asynchronous Motor." Advanced Materials Research 756-759 (September 2013): 768–74. http://dx.doi.org/10.4028/www.scientific.net/amr.756-759.768.
Повний текст джерелаАнотація:
Alternating current (AC) machine speed regulation system plays a very important role in our industrial and agricultural production. This paper focuses on the three-phase asynchronous motor which account for most of the proportion of the AC machines. Firstly, this paper establishes three mathematical models of asynchronous motor based on dq coordinate system and introduces the principle of V/f speed-adjusting for asynchronous motor, and then the paper builds the simulation models of V/f speed-adjusting control system for asynchronous motor based on Matlab/Simulink. The simulation results of the V/f speed-adjusting control system verifies the correctness of the simulation models and the principle of speed regulation.
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Olszak, Artur, Karol Osowski, Zbigniew Kęsy, and Andrzej Kęsy. "Modelling and testing of a hydrodynamic clutch filled with electrorheological fluid in varying degree." Journal of Intelligent Material Systems and Structures 30, no. 4 (January 6, 2019): 649–60. http://dx.doi.org/10.1177/1045389x18818780.
Повний текст джерелаАнотація:
The article concerns steady-state characteristics of a hydrodynamic clutch with electrorheological working fluid controlled by changes in strength of electric field and changes in the filling degree. The characteristics were obtained by experimenting, as well as calculations based on one-dimensional mathematical models. While creating the mathematical models, factors taken into consideration included differences between methods controlling the clutch, as well as various ways the working fluid flows in the clutch’s working space, depending on the relation of angular speed of rotors. The resultant mathematical models were verified with experimental research.
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Osiadacz, Andrzej J., and Marta Gburzyńska. "Selected Mathematical Models Describing Flow in Gas Pipelines." Energies 15, no. 2 (January 10, 2022): 478. http://dx.doi.org/10.3390/en15020478.
Повний текст джерелаАнотація:
The main aim of simulation programs is to study the behavior of gas pipe networks in certain conditions. Solving a specified set of differential equations describing transient (unsteady) flow in a gas pipeline for the adopted parameters of load and supply will help us find out the value of pressure or flow rate at selected points or along selected sections of the network. Transient gas flow may be described by a set of simple or partial differential equations classified as hyperbolic or parabolic. Derivation of the mathematical model of transient gas flow involves certain simplifications, of which one-dimensional flow is most important. It is very important to determine the conditions of pipeline/transmission network operation in which the hyperbolic model and the parabolic model, respectively, should be used. Parabolic models can be solved numerically in a much simpler way and can be used to design simulation programs which allow us to calculate the network of any structure and any number of non-pipe elements. In some conditions, however, they describe the changes occurring in the network less accurately than hyperbolic models do. The need for analysis, control, and optimization of gas flows in high-pressure gas pipelines with complex structure increases significantly. Very often, the time allowed for analysis and making operational decisions is limited. Therefore, efficient models of unsteady gas flows and high-speed algorithms are essential.
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González-Hernández, José Genaro, and Rubén Salas-Cabrera. "Wind Power Extraction Optimization by Dynamic Gain Scheduling Approximation Based on Non-Linear Functions for a WECS Based on a PMSG." Mathematics 9, no. 17 (August 24, 2021): 2028. http://dx.doi.org/10.3390/math9172028.
Повний текст джерелаАнотація:
Mathematical models and algorithms for maximizing power extraction have become an essential topic in renewable energies in the last years, especially in wind energy conversion systems. This study proposes maximum power point tracking using gain scheduling approximations for an emulated wind system in a direct-drive connection. Power extraction is obtained by controlling the duty cycle of a Multilevel Boost Converter, which directly varies the rotational speed of a permanent magnet synchronous generator directly coupled to a three-phase induction motor that emulates the wind turbine. The system’s complexity is linked to the inherent non-linearities associated with the diverse electrical, mechanical, and power electronic elements. In order to present a synthesized model without losing the system dynamic richness, several physical tests were made to obtain parameters for building several mathematical approaches, resulting in non-linear dynamic equations for the controller gains, which are dependant on wind speed. Thirty real operational wind speeds considering typical variations were used in several tests to demonstrate the mathematical models’ performance. Results among these gain scheduling approaches and a typical controller constant gains mathematical model were compared based on standard deviations, absolute error, and the time for reaching the optimum generator angular speed related to every wind speed.
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Briggs, Tobinson, and Shadrack Mathew Uzoma. "Computer Simulation Models for Profit Maximisation in a Paint Production Company." European Journal of Engineering Research and Science 5, no. 1 (January 14, 2020): 8–11. http://dx.doi.org/10.24018/ejers.2020.5.1.1679.
Повний текст джерелаАнотація:
Paint manufacturing is an advanced area of technology in the world. Necessarily paints are applied to any structure or body for a virtuous number of reasons : corrosion protection, aesthetic features to create attractive colours on buildings to protect it from environmental degradation and none the less to protect the bodies of automobiles, aircraft, and ships from ecological damage; also to give the right shades of colours catching to the eyes and minds of customers. In this research work, mathematical models developed by the researchers were employed to maximise the profit margin of a painting Company. The mathematical optimisation models are Linear Programming production demand-based planning models. It is geared towards maximising the profit of the establishment subject to a certain number of critical constraints. Lindo computer software was employed in the simulation to access the profitability index of the company subject to demand constraints. Revenue accruable from sales of the items produced was ten million and six hundred and twenty-seven thousand sixty-two naira and fifty-three kobo (N10, 627,062.53). The different cost inputs resulted in the expenditure of ten million and six hundred and ten thousand and six forty naira (N10, 610,640.00). The profit margin is sixteen thousand four hundred and twenty-two naira and fifty-three kobo (N16,422.53). Profit optimisation maximisation procedure using Lindo Computer Software resulted in a profit margin of twenty-nine thousand one hundred and ten naira (N29,100.00). The percentage difference in profit margin is 77.26%. The simulation profit optimisation results revealed a tremendous difference in turnover margin and called for an interaction with the Academy Color Paint Company for enhancement in the turnover margin of their establishment.
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Briggs, Tobinson, and Shadrack Mathew Uzoma. "Computer Simulation Models for Profit Maximisation in a Paint Production Company." European Journal of Engineering and Technology Research 5, no. 1 (January 14, 2020): 8–11. http://dx.doi.org/10.24018/ejeng.2020.5.1.1679.
Повний текст джерелаАнотація:
Paint manufacturing is an advanced area of technology in the world. Necessarily paints are applied to any structure or body for a virtuous number of reasons : corrosion protection, aesthetic features to create attractive colours on buildings to protect it from environmental degradation and none the less to protect the bodies of automobiles, aircraft, and ships from ecological damage; also to give the right shades of colours catching to the eyes and minds of customers. In this research work, mathematical models developed by the researchers were employed to maximise the profit margin of a painting Company. The mathematical optimisation models are Linear Programming production demand-based planning models. It is geared towards maximising the profit of the establishment subject to a certain number of critical constraints. Lindo computer software was employed in the simulation to access the profitability index of the company subject to demand constraints. Revenue accruable from sales of the items produced was ten million and six hundred and twenty-seven thousand sixty-two naira and fifty-three kobo (N10, 627,062.53). The different cost inputs resulted in the expenditure of ten million and six hundred and ten thousand and six forty naira (N10, 610,640.00). The profit margin is sixteen thousand four hundred and twenty-two naira and fifty-three kobo (N16,422.53). Profit optimisation maximisation procedure using Lindo Computer Software resulted in a profit margin of twenty-nine thousand one hundred and ten naira (N29,100.00). The percentage difference in profit margin is 77.26%. The simulation profit optimisation results revealed a tremendous difference in turnover margin and called for an interaction with the Academy Color Paint Company for enhancement in the turnover margin of their establishment.
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Dubanov, A. "Geometric models of the run method." Journal of Physics: Conference Series 2131, no. 3 (December 1, 2021): 032044. http://dx.doi.org/10.1088/1742-6596/2131/3/032044.
Повний текст джерелаАнотація:
Abstract This article discusses models of the run method in the pursuit problem. The considered models are based on the correction of the direction vector. Let’s assume that the intended direction on a plane is the line of sight between the pursuer and the target. The direction correction consists in the rotation of the velocity vector until it coincides with the line of sight. When constructing trajectories on the surface, a line of sight is built on the horizontal projection plane. After calculating horizontal projections, all points are projected back onto the surface. On the basis of the research carried out proposed a mathematical model, proposed mathematical models of the method of pursuit on a plane and on a surface given in an explicit form. Mathematical models are the development of chase and parallel approach methods. A modification of these methods is that the speed of the pursuer and the target are directed at random. These models can be in demand by developers of autonomous unmanned vehicles equipped with artificial intelligence systems.
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Kuzyshyn, A. Y., S. A. Kostritsia, Yu H. Sobolevska, and А. V. Batih. "World Experience in Creating Mathematical Models of Air Springs: Advantages and Disadvantages." Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport, no. 4(94) (August 17, 2021): 25–42. http://dx.doi.org/10.15802/stp2021/245974.
Повний текст джерелаАнотація:
Purpose. Taking into account the production and commissioning of modern high-speed rolling stock, the authors are aimed to analyze the currently created mathematical models describing the dynamic behavior of the air spring, systematize them and consider the advantages and disadvantages of each model type. Methodology. For the analysis, a comparative chronological method was used, which makes it possible to trace the development of several points of view, concepts, theories. In accordance with the adopted decision equations, the existing models of air springs were divided into three groups: mechanical, thermodynamic and finite-elements. When analyzing mathematical models, the influence of a number of parameters on the dynamic behavior of the air spring, such as disturbing force frequency, heat transfer, nonlinear characteristics of materials, the shape of the membrane, etc., was considered. Findings. A feature of mechanical models is the determination of input parameters based on the analysis of experimental results, requires access to complex measuring equipment and must be performed for each new model of an air spring separately. Unlike mechanical models, which allow taking into account the damping effect of an air spring in the horizontal and vertical direction, thermodynamic models are mainly focused on studying the dynamic behavior of an air spring in the vertical direction. The use of the finite element method makes it possible to most accurately reproduce the dynamic behavior of an air spring, however, it requires significant expenditures of time and effort to create a finite element model and perform calculations. Originality. Mathematical models of the dynamic behavior of an air spring are systematized, and the importance of their study in conjunction with a spatial mathematical model of high-speed rolling stock is emphasized. Practical value. The analysis of the mathematical models of the dynamic behavior of the air spring shows the ways of their further improvement, indicates the possibility of their use in the spatial mathematical model of the rolling stock in accordance with the tasks set. It will allow, even at the design stage of high-speed rolling stock, to evaluate its dynamic characteristic and traffic safety indicators when interacting with a railway track.