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PROKHORENKO, Andriy, Dmytro SAMOILENKO, Piotr ORLINSKI, Dmytro TALANIN, and Serhii KRAVCHENKO. "The application of isodromic equation for calculation of PID-controller integrated component." Combustion Engines 177, no. 2 (May 1, 2019): 91–94. http://dx.doi.org/10.19206/ce-2019-216.
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A functional feature of the application of electronics used for the automatic control of internal combustion engines is necessity in the proportional conversion of ECU electrical signals into the mechanical processes based on corresponding elements motion. For such conversion of information actuating mechanisms are used, referred as actuators. Actuators in the form of electrical machines (stepper or precision electric motors) or electric apparatuses (electromagnets and solenoids) are the mostly widespread in ICE. As a physical object of the research, the unit of Heinzmann, model StG 6-02V that is based on a DC electric drive controlled by a pulse-width modulation signal, was selected in the current work. It has a toothed gearbox and a non-contact reverse positional connection. This actuator pro-vides an output torque of 6 Nm and 36-degree range of output shaft rotational angle. The functional scheme of the electronic system of automatic control of a diesel engine based on mentioned device is developed. The PID regulator with feedback is used to control the actuator. A design formula that can be incorporated in the controller algorithm to calculate the integral component of the PID regulator was also obtained. Values of empirical coefficients were determined in this formula. The results of experimental confirmation of the correctness of the approach taken are presented. Thus, the new formula for determining the integral component of the PID regulator differs positively from the well-known solutions because the new approach is free from storing the whole array of previous data with discrepancy in the controller’s RAM, that simplifies the application of the developed algorithm greatly and speeds up the computational capability of the controller.
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Wang, Haibo, Yongfeng Cheng, Zhicheng Lu, Zhubing Zhu, and Shujun Zhang. "Research on Bending Rigidity at Flange Connections of UHV Composite Electrical Equipment." Shock and Vibration 2020 (March 13, 2020): 1–10. http://dx.doi.org/10.1155/2020/2031357.
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Pillar electrical equipment is an important part of substations. The application of composite materials in pillar equipment can facilitate the improvement of the seismic performance of electrical equipment. In this paper, the test of elastic modulus and bending rigidity was conducted for individual composite elements in insulators and arresters, and the calculation formula for bending rigidity at the composite flange cementing connections was put forward. The numerical simulation model for the earthquake simulation shaking table test of ±1,100 kV composite pillar insulators was established, in which the bending rigidity value for the flange cementing part was obtained by the test or calculation formula. The numerical simulation results were compared with the earthquake simulation shaking table test results, the dynamic characteristics and seismic response of the model were compared, respectively, the validity of the proposed calculation formula for flange bending rigidity of composite cementing parts was verified, and a convenient and effective means was provided for calculating the seismic performance of composite electrical equipment.
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Asamoah, F. "Calculation of Forces in Dynamic Mechanical Systems: Driving point Impedance Approach." International Journal of Electrical Engineering & Education 29, no. 3 (July 1992): 255–64. http://dx.doi.org/10.1177/002072099202900308.
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Calculation of forces in dynamic mechanical systems — driving point impedance approach This paper extends the concept of driving point impedance used in analog electronic systems to dynamic mechanical systems. The similarity between the equations and the bus-impedance matrix equations in power systems is pointed out. Examples have been given to demonstrate the application of the method.
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Premovic, Milena, Aleksandar Djordjevic, Dusko Minic, Milica Tomovic, Branko Radicevic, and Nemanja Kolarevic. "Mechanical and electrical properties of the Bi-Ge-Sn alloys." Metallurgical and Materials Engineering 26, no. 4 (December 31, 2020): 395–412. http://dx.doi.org/10.30544/562.
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Mechanical and electrical properties of the ternary Bi-Ge-Sn alloys were investigated in this study. Calculation of isothermal section at 200, 300, and 25 ºC was carried out by using optimized thermodynamic parameters for the constitutive binary systems. Microstructures of alloys were observed by using optical microscopy and scanning electron microscopy (SEM). Phases in microstructures have been detected by X-ray diffraction (XRD) analysis and compositions of the phase by energy dispersive spectrometry (EDS). EDS results were compared with the predicted isothermal section at 200 and 300 ºC, and good agreement has been reached between them. The Brinell hardness and electrical conductivity of selected alloys were measured. Through ANOVA analysis and application of the obtained results, an appropriate mathematical model is proposed for every composition of alloys. By using the appropriated mathematical model for Brinell hardness and electrical conductivity, isolines for those properties were presented.
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Bégué, D., I. Baraille, P. A. Garrain, A. Dargelos, and T. Tassaing. "Calculation of IR frequencies and intensities in electrical and mechanical anharmonicity approximations: Application to small water clusters." Journal of Chemical Physics 133, no. 3 (July 21, 2010): 034102. http://dx.doi.org/10.1063/1.3457482.
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Taebnia, Mehdi, Sander Toomla, Lauri Leppä, and Jarek Kurnitski. "Developing energy calculation methodology and calculation tool validations: Application in air-heated ice rink arenas." Energy and Buildings 226 (November 2020): 110389. http://dx.doi.org/10.1016/j.enbuild.2020.110389.
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SKRYPNYK, S., and A. SHEINA. "Short circuits currents comparison of 6 (10) kV and 20 kV." Journal of Electrical and power engineering 14, no. 1 (February 27, 2020): 21–26. http://dx.doi.org/10.31474/2074-2630-2020-1-21-26.
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Most failures in electrical installations are caused by short circuits (short circuits), which occur as a result of a failure in the electrical strength of the insulation of the conductive parts. A short circuit is an electrical connection of two points of an electric circuit with different values of potential, which is not provided by the design of the device, which interferes with its normal operation. Short circuits may result from a failure of the insulation of the current-carrying elements or the mechanical contact of the non- insulated elements. Also called a short circuit is a condition where the load resistance is less than the internal resistance of the power source. The reasons for such violations are various: aging of insulation, breakages of wires of overhead transmission lines, mechanical damages of isolation of cable lines at ground works, lightning strikes in the transmission line and others. Most often, short-circuits occur through transient resistance, such as through the resistance of an electric arc that occurs at the point of damage to the insulation. Sometimes there are metallic short circuits in which the resistance of the electric arc is very small. The study of short circuits in the power grid is a major step in the design of modern electrical networks. The research is conducted using computer software, first by modeling the system and then simulating errors. A malfunction usually leads to an increase in the current flowing in the lines, and failure to provide reliable protection can result in damage to the power unit. Thus, short-circuit calculations are the primary consideration when designing, upgrading, or expanding a power system. The three-phase short circuit is the least likely. However, in many cases, the three-phase short circuit is associated with the most severe consequences, as it causes the highest power imbalances on the shafts of the generators. The study of transients begins with the mode of three-phase closure due to its relative simplicity in comparison with other types of asymmetry. In most cases, the analysis and calculation of the transient regime of the electrical system involves the preparation of a calculated scheme of substitution, in which the parameters of its elements are determined in named or relative units. The electrical substitution circuitry is used to further study the transients in the power system. The definition of electrical and electromagnetic quantities in relative units is widely used in the theory of electric machines. This is because it significantly simplifies the theoretical calculations and gives the results a generalized view in the practical calculations of currents and residual voltages at the short circuit. By the relative value of any value is understood as its relation to another value of the same name, taken as the base. So, before presenting any quantities in relative units, we need to choose the basic units. In the electrical system with increased voltages, the overall load capacity of the network increases, which in turn makes it possible to supply high-quality electrical energy over a greater distance. In the process of comparing the type of transmission lines, it should be noted that the advantages of the cable transmission line. According to the results of the calculation of short-circuit currents, it can be concluded that in networks with a larger line cross-section and a higher voltage, the short-circuit currents are larger. Thus, during the transition of the electric networks to the higher voltage class of 20 kV, the currents of the KZ increased by 43% compared to the 6 kV electric network. This analysis shows that the importance of reliable power supply in the power supply system for high voltage classes must be high and have equipment to prevent emergencies. In the future, it is planned to develop a systematic calculation of short-circuit currents for a number of transmission lines and to conduct mathematical modeling in the system of applications for the study of transient processes at short circuits.
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Chen, Yi-Heng, and Tian Jian Lu. "Recent developments and applications of invariant integrals." Applied Mechanics Reviews 56, no. 5 (August 29, 2003): 515–52. http://dx.doi.org/10.1115/1.1582199.
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Although invariant integrals (path independent integrals) have been used extensively in the 20th century, mainly in the calculation of dominant parameters that govern the initiation and propagation of both linear and nonlinear cracks, new applications are increasingly being identified. This article presents developments and applications of the invariant integrals in recent years, focusing on four major application areas: i) fracture mechanics of functional materials (eg, piezoelectric ceramics and ferromagnets), which exhibit features different from those found in purely mechanical problems due to the coupling of electric, magnetic, thermal, and mechanical quantities; ii) damage mechanics of multiple interacting cracks, and new damage measures; iii) domain integrals, two-state integrals, and their applications in determining the dominant parameters of 3D cracks and in clarifying the role of higher order singular terms in the Williams eigenfunction expansions; and iv) nano-structures (eg, stress driven surface evolution in a heteroepitaxial thin film). In writing this review article, we have been able to draw upon a large number of published works on invariant integrals over the last three decades, and yet it is impossible to cover the whole subject in the limited space available. Consequently, the main aim of the article is to summarize the major developments and applications in the four important areas mentioned above. Still, 261 references are reviewed in the article.
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Friedrich, Sebastian, and Brunero Cappella. "Application of contact-resonance AFM methods to polymer samples." Beilstein Journal of Nanotechnology 11 (November 12, 2020): 1714–27. http://dx.doi.org/10.3762/bjnano.11.154.
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Contact-resonance AFM (CR-AFM) has been used in recent years for the measurement of mechanical properties of rather stiff materials, such as ceramics or metals, but also of some polymers. Compared with other techniques providing information on the mechanical properties of a sample, notably force–distance curves, CR-AFM has a much shorter acquisition time. This compensates in part the incomplete theoretical understanding of the underlying physical phenomena and of factors influencing the measurements. A commonly used method to analyze CR data requires the determination of the relative position of the tip, the calculation of the normalized contact stiffness, and the use of a calibration sample for the calculation of the elastic modulus of the sample. In the present paper, we propose an alternative procedure, based on approximations of the equations describing the system, which allows one to determine the elastic modulus of the sample as a parameter of the fit of the CR frequency as a function of the load. After showing that CR modes including scanning under continuous contact wear and damage the sample and/or alter the surface roughness, the results of point CR measurements on bulk and thin films are presented. Though Young’s moduli of bulk polystyrene and poly(methyl methacrylate) could be determined through the presented analysis, it is concluded that CR measurements are not appropriate for polymer samples. Major drawbacks are the bad resolution for moduli lower than ca. 10 GPa and the lack of a comprehensive physical model accounting for many factors affecting the dynamic response of a cantilever in contact with a sample.
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Marković, Branislav Radomir, Dragan Manasijević, Nadežda Talijan, Miroslav Sokić, Nada Štrbac, Aleksandra Patarić, and Mladen Bugarčić. "Ternary Bi-Cu-Ni alloys – thermodynamics, characterization, mechanical and electrical properties." Metallurgical and Materials Engineering 23, no. 3 (September 30, 2017): 241–54. http://dx.doi.org/10.30544/316.
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The Bi–Cu–Ni ternary system belongs to the group of potential Cu-Ni-based advanced lead-free solder materials for high temperature application. The paper shows results of the thermodynamic calculations using general solution model along the line with the molar ratio of Cu: Ni = 1:1. The experimental part shows thermal, structural, electrical and mechanical properties based on differential scanning calorimetry (DSC), scanning electron microscopy with energy dispersive spectrometry (SEM-EDS), electroconductivity and hardness measurements of the alloys selected in the section from bismuth corner with molar ratio Cu: Ni = 1:1, Cu: Ni = 3:1, and Cu: Ni = 1:3.
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Akhatov, S. T., V. G. Solonenko, N. M. Makhmetova, S. A. Kosenko, N. V. Ivanovtseva, and A. A. Malik. "APPLICATION OF LINEAR ASYNCHRONOUS MOTORS FOR HIGH-SPEED GROUND TRANSPORT." Series of Geology and Technical Sciences 2, no. 446 (April 15, 2021): 31–36. http://dx.doi.org/10.32014/2021.2518-170x.31.
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Magnetic suspension in high-speed ground transport systems is an alternative to the rail wheel. The successful solution to the development of high-speed ground transport is largely determined by the creation of operationally efficient linear motors, the main task of which is to convert electrical energy into mechanical energy and create tractive force to ensure the movement of the crew according to a given program in the range of operating speeds. The article investigates linear asynchronous motors with longitudinal closure of magnetic flux of single-ended design. As a result of investigation of physical processes in linear motors caused by edge problems it was found that the cause of the transverse edge effect is the finite width dimensions of the reactive bus, the change of which causes closure of eddy currents within the active area of inductor, leads to weakening of magnetic field in the central zone and to reduction of tractive force. The discrepancy between the calculated and experimental indicators of physical processes in linear asynchro- nous motors due to significant idealization of mathematical models led to the development of a three-dimensional theory, brought to the calculation programs. The developed calculation program of electromechanical characteristics of linear induction motors with inductor and reactive bus layout, as well as their geometrical and physical parameters allows to determine the necessary integral motor characteristics in the form of a levitation function.
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Yuan, Haomiao, and Jian Song. "An Improved Calculation Model for the Prediction of the Wear of Coated Electrical Contacts." Technologies 7, no. 4 (October 31, 2019): 77. http://dx.doi.org/10.3390/technologies7040077.
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To connect terminals in a cyber–physical system, large quantities of electrical contacts are used. In order to guarantee a high reliability of the system, the lifetime of the electrical contacts should be very long. Thus, it is of great importance to understand the failure mechanism and then to predict the lifetime of the electrical contacts. For the applications under high thermal and/or mechanical loads, noble plating is a good choice, considering its inertness to oxidation. For noble plating, one of the most critical failure mechanisms is the fretting wear. Wear debris generated in the contact area, acting as the third bodies, will greatly influence the further wear behavior and electrical performance. In this study, the state of the art regarding third bodies is firstly reviewed, and then the influence of the third bodies on the wear and electrical performance is investigated, from the aspects of lifetime and the element distributions in contact area. Finally, an example of prediction of the wear of noble plating is shown with the consideration of the third bodies. Based on this study, by involving the third bodies, the wear of noble plating can be predicted with a higher accuracy.
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Ermoshkin, Anton, Ivan Timoshkin, and Alfiya Lutz. "Hardening of Aluminum Alloys with Nano-Dispersed Inclusions during the Implementation of Energy-Saving Process of Self-Propagating High-Temperature Synthesis in Aluminum Melt." Applied Mechanics and Materials 792 (September 2015): 590–95. http://dx.doi.org/10.4028/www.scientific.net/amm.792.590.
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It was demonstrated that the application of self-propagating high-temperature synthesis as a low energy expenditure method to produce alloys of the Al-TiC system is of high priority. The process for the preparation of the charge and obtaining a composite alloywere described. The results of studies of electrical conductivity and mechanical properties of aluminum matrix composite alloys, modified with nanoparticles of titanium carbide TiC werepresented.Alloys with compositions: Al-10% TiC, Al7%Si + 10% TiC and Al9%Si + 10% TiC, as well as the original matrix materials: pure aluminum and Al9%Si werestudied. The index of plasticity was obtained by calculation. This calculated value showed that the experimental samples are small crystalline materials and nanomaterials. It was shown that the addition of nanoparticles of titanium carbide improves the mechanical properties of the initial alloy, without significantly reducing the electrical conductivity (no more than 30%).
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Ivanovа, V. R., and I. N. Kiselev. "Frequency-adjustable electric drive for energy saving and optimization of technological processes in electrical complexes." Power engineering: research, equipment, technology 21, no. 5 (December 17, 2019): 59–70. http://dx.doi.org/10.30724/1998-9903-2019-21-5-59-70.
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The relevance of the study lies in the search for energy-saving technologies. So, at present, the most common type of electric drive in industry is asynchronous, most of which are unregulated. Replacing an unregulated electric drive with an adjustable one in various units can significantly reduce energy consumption, increase the life of the mechanical part of the drive and improve the quality of the adjustable process parameter. The replacement consists in installing an electronic frequency converter between the network and the motor of the device. This device changes the rotational speed of the motor rotor by changing the frequency and amplitude of the supply voltage. The most common are frequency converters with an intermediate DC link. Such devices are built on electronic keys, which are made on IGBT (Insulated Gate Bipolar Transistor) transistors. Using the NI Multisim14 software, a model was created to determine power savings during the implementation of VFD.The paper gives the rationale for the introduction of a frequency-controlled electric drive (VFD) to optimize technological processes in electrical complexes and systems, in particular, a complete analysis of the energy efficiency of VFD application in pumped water supply systems is presented as an example. The calculation of its economic efficiency for a particular installation is also given.
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Park, R., K. V. Kaler, and T. Jones. "A Nonequilibrium Statistical Mechanical Calculation of the Surface Conductance of the Electrical Double Layer of Biological Cells and Its Application to Dielectrophoresis." Journal of Physical Chemistry 97, no. 18 (May 1993): 4745–55. http://dx.doi.org/10.1021/j100120a600.
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Albizu, I., A. J. Mazón, V. Valverde, and G. Buigues. "Aspects to take into account in the application of mechanical calculation to high-temperature low-sag conductors." IET Generation, Transmission & Distribution 4, no. 5 (2010): 631. http://dx.doi.org/10.1049/iet-gtd.2009.0543.
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Своробин, Дмитрий Сергеевич, Александр Анатольеви Фоков, and Сергей Викторович Хорошилов. "АНАЛИЗ ЦЕЛЕСООБРАЗНОСТИ ИСПОЛЬЗОВАНИЯ АЭРОДИНАМИЧЕСКОГО КОМПЕНСАТОРА ПРИ БЕСКОНТАКТНОМ УДАЛЕНИИ КОСМИЧЕСКОГО МУСОРА." Aerospace technic and technology, no. 6 (December 20, 2018): 4–11. http://dx.doi.org/10.32620/aktt.2018.6.01.
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The article deals with the feasibility of aerodynamic compensator application in the scheme of the so-called noncontact method of space debris removal on the low near-earth orbits without mechanical contact of the spacecraft and space debris. Previously, in relation to one of the technologies for implementing such method of collection, referred to as "the shepherd with an ion beam", its modification was proposed, which consists in replacing the compensating electro jet engine with an aerodynamic compensator. The original compensating engine serves to compensate the reactive power of the main electric jet engine, which torch ion flow has a “braking” effect on the space debris. The idea of modifying the technology was to save the cost of an expensive working jet engine and reduce the starting mass of the shepherd’s spacecraft. However, this assumption was not sufficiently substantiated. The analysis of the feasibility of aerodynamic compensator application is made on the basis of calculating the mass of the working medium and the amount of electrical energy saved due to its application. The above mentioned calculation of the saved mass of the working fluid is made applying a number of simplifying assumptions. As a result of the analysis, it was determined that the expediency of aerodynamic compensator applying is not obvious, considering the mass of the compensator and the complexity of the design of the spacecraft. At the same time, if in one mission of the shepherd’s spacecraft will presuppose to carry out several space debris removal on the orbit, then the application of an aerodynamic compensator become justified. The direction of further research involves a more detailed analysis of the feasibility of aerodynamic compensator application, including the elaboration of the compensator design, its mid-area control method, and simulation of the orbital and relative motion of the shepherd – space debris, consider the disturbing factors and the relative motion control algorithm
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Smolentsev, V. P., A. V. Levin, and A. V. Gribentchikov. "Manufacturing of Coated Production Tooling." Advanced Materials Research 24-25 (September 2007): 13–16. http://dx.doi.org/10.4028/www.scientific.net/amr.24-25.13.
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It is difficult to select the materials combining in modern industry, this paper analyzed the drawbacks of different materials (the stainless, the copper alloys, aluminum and its alloys) on selecting materials for tooling and selection of coatings that help to eliminate drawbacks, analyzed the micro-arc oxidation (MAO) and its application of different materials. It is ascertained that aluminum alloys may be practical to use for electrodes for electroerosive machining only in exceptional cases when the wear of the tool is not determinative. Selection of materials combining required physical and mechanical properties may be a difficult task in tooling designing and manufacturing in modern industry. This problem is especially evident when current-conducting elements of tooling used for electrophysical and electrochemical processing methods are manufactured. The main distinctive feature of these methods is maintenance of values under the influence of electrical current and corrosive medium and during electrochemical reactions. The article addresses comparative analysis of properties of different materials used for tooling manufacture, advantages and drawbacks of these materials and selection of coatings that help to eliminate drawbacks. When selecting materials for tooling, the alloy in use shall have the following properties [4]: high electrical conductivity, high corrosion resistance, high resistance to local fracture, high adhesion to dielectric coatings, sufficient mechanical strength, high machinability and low cost. The following materials are considered to meet operating requirements to the fullest extend [4.5]: stainless steels and copper alloys that have high machinability, electrical conductivity, weldability and mechanical strength; titanium- and chromium-base alloys that have high mechanical strength, corrosion resistance and resistance to local fracture and enables to make oxide insulating layer protecting surface from anodic dissolution. However, these materials have a number of drawbacks, the most important of which is high cost that impedes their usage especially in serial production. Furthermore, stainless steels and titaniumand chromium-base alloys have the following drawbacks that affect product cost: - complexity of machinability that results in high labor-intensiveness of manufacturing process of tooling; - heavy losses in electric voltage provided that these materials are used as current-carrying elements that makes current supply calculation difficult and requires application of more powerful sources; - cracking and fracture of oxide surface coating even when mechanical effect is insignificant that results in loss of isolating and protective properties [1,2]. Furthermore, oxide coating application process cannot be controlled completely and as a result, coating uniformity in thickness, composition and properties cannot be achieved. Application of coatings to the areas with varied sections and to the surfaces with projections and sharp edges is a difficult problem. Layers applied to these surfaces have little adhesion to parent material and their thickness is limited due to high stress concentration and etching. The revealed drawbacks require development and usage of surface layer improvement process to receive required physical and mechanical properties of composite material.
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Bossis, G., C. Abbo, S. Cutillas, S. Lacis, and C. Métayer. "ELECTROACTIVE AND ELECTROSTRUCTURED ELASTOMERS." International Journal of Modern Physics B 15, no. 06n07 (March 20, 2001): 564–73. http://dx.doi.org/10.1142/s0217979201005027.
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Electroactive elastomers are composites made of solid particles embedded in an elastomeric network whose mechanical or optical properties can be changed by the application of an electric or a magnetic field. These materials have obviously a strong connection with ER and MR fluids and can be more appropriated for some applications. We present recent results concerning two kinds of filled elastomer, one based on carbonyl iron particles and the second one on silica particles. In the first case we show that that change of elastic properties obtained by the application of a magnetic field depend dramatically on the way we have structured the suspension before the polymerization. We explain quantitatively these experimental results with the help of finite element calculation to predict the magnetic forces between the particles. In the second case we show how it is possible to modulate the transmission of a laser beam by shearing a thin elastomeric film whose particles have been initially aligned with the help of an electric field. Some applications related to the organization of the filler particles by the application of a field or a combination of a field and a flow before polymerization will be discussed.
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McCloskey, Alex, Xabier Arrasate, Xabier Hernández, Iratxo Gómez, and Gaizka Almandoz. "Analytical calculation of vibrations of electromagnetic origin in electrical machines." Mechanical Systems and Signal Processing 98 (January 2018): 557–69. http://dx.doi.org/10.1016/j.ymssp.2017.04.050.
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Song, Min-Su, Sung-Gu Kang, Kyu-Tae Lee, and Jeonghyun Kim. "Wireless, Skin-Mountable EMG Sensor for Human–Machine Interface Application." Micromachines 10, no. 12 (December 14, 2019): 879. http://dx.doi.org/10.3390/mi10120879.
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The development of advanced technologies for wireless data collection and the analysis of quantitative data, with application to a human–machine interface (HMI), is of growing interest. In particular, various wearable devices related to HMIs are being developed. These devices require a customization process that considers the physical characteristics of each individual, such as mounting positions of electrodes, muscle masses, and so forth. Here, the authors report device and calculation concepts for flexible platforms that can measure electrical signals changed through electromyography (EMG). This soft, flexible, and lightweight EMG sensor can be attached to curved surfaces such as the forearm, biceps, back, legs, etc., and optimized biosignals can be obtained continuously through post-processing. In addition to the measurement of EMG signals, the application of the HMI has stable performance and high accuracy of more than 95%, as confirmed by 50 trials per case. The result of this study shows the possibility of application to various fields such as entertainment, the military, robotics, and healthcare in the future.
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Skrzypek, S. J., M. Goły, J. Kowalska, and K. Chruściel. "Thickness of Polycrystalline Copper Coating Measured by X-Ray Diffraction." Solid State Phenomena 163 (June 2010): 9–12. http://dx.doi.org/10.4028/www.scientific.net/ssp.163.9.
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Electrodeposition and other methods are employed to obtain metallic films and coatings. Copper coatings are most extensively used in circuit board industry and often as a base to further formation of other metallic films. Electrodeposited copper films (thin layers) are widely used in electronic and automotive industry so its electrical and mechanical properties and its thickness are important. Several methods are used for thickness determination of thin films and coatings for example mechanical, magnetic and ball crater with light microscopy methods. They are destructive and not precise enough. The X-ray fluorescence, absorption and diffraction are more frequently used due to better precision. Although they are complex and expensive, they pronounce an important feature like non-destructive character. For particular cases geometrical conditions and mathematical calculation procedure must be elaborated. An application of X-ray diffraction in grazing incidence angle for thickness determination is described in this article. The method is based on absorption principles of X-ray beam. The absorption is proportional to thickness of the coating and to incidence and to the diffraction angle which. Geometrical conditions were obtained experimentally and suitable mathematical calculations were introduced. The elaborated methodical approach was applied to thickness determination of copper coatings electrodeposited on a brass substrate.
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Chaban, Andriy, Marek Lis, Andrzej Szafraniec, and Radoslaw Jedynak. "Application of Genetic Algorithm Elements to Modelling of Rotation Processes in Motion Transmission Including a Long Shaft." Energies 14, no. 1 (December 28, 2020): 115. http://dx.doi.org/10.3390/en14010115.
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Genetic algorithms are used to parameter identification of the model of oscillatory processes in complicated motion transmission of electric drives containing long elastic shafts as systems of distributed mechanical parameters. Shaft equations are generated on the basis of a modified Hamilton–Ostrogradski principle, which serves as the foundation to analyse the lumped parameter system and distributed parameter system. They serve to compute basic functions of analytical mechanics of velocity continuum and rotational angles of shaft elements. It is demonstrated that the application of the distributed parameter method to multi-mass rotational systems, that contain long elastic elements and complicated control systems, is not always possible. The genetic algorithm is applied to determine the coefficients of approximation the system of Rotational Transmission with Elastic Shaft by equivalent differential equations. The fitness function is determined as least-square error. The obtained results confirm that application of the genetic algorithms allow one to replace the use of a complicated distributed parameter model of mechanical system by a considerably simpler model, and to eliminate sophisticated calculation procedures and identification of boundary conditions for wave motion equations of long elastic elements.
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J, Paul Rajasingh, Sharmishtha Sen*, and Shreyes Prasad. "User Reputation Calculation for Service-Oriented Environments." Regular issue 10, no. 7 (May 30, 2021): 107–9. http://dx.doi.org/10.35940/ijitee.g8953.0510721.
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All the cloud based applications work on serviceoriented architectures and collaborate with multiple components from other services to execute discreet application logic. In this environment there are a lot of Web services facilitated to the customer to make the systems. As the potential of the same Web service will change with respect to users' needs. On an average a user will be heavily relied on tools to aid their activities on the internet vice versa the Service provider are also dependent on the users profile and what services are being used in the system. A User Reputation model offers a solution to the Service providers in supporting their service decision based on the User Profile. This model takes usage ratings as data and produces a personalised score. We suggest a new Cumulative separation on the basis of Tags and popularity estimation method and showcase its enhanced filtration ability.
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Hu, Jian, Xiaofu Xiong, and Jian Wang. "Current Tolerance Capability Calculation Model of Transmission Lines and its Application in Overload Protection." Electric Power Components and Systems 46, no. 14-15 (September 14, 2018): 1509–21. http://dx.doi.org/10.1080/15325008.2018.1511005.
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Wei, Huihui, Jiatian Guo, Xiaobo Yuan, and Junfeng Ren. "Spin Polarization Properties of Two Dimensional GaP3 Induced by 3d Transition-Metal Doping." Micromachines 12, no. 7 (June 24, 2021): 743. http://dx.doi.org/10.3390/mi12070743.
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The electronic structure and spin polarization properties of monolayer GaP3 induced by transition metal (TM) doping were investigated through a first-principles calculation based on density functional theory. The calculation results show that all the doped systems perform spin polarization properties, and the Fe–doped system shows the greatest spin polarization property with the biggest magnetic moment. Based on the analysis from the projected density of states, it was found that the new spin electronic states originated from the p–d orbital couplings between TM atoms and GaP3 lead to spin polarization. The spin polarization results were verified by calculating the spin density distributions and the charge transfer. It is effective to introduce the spin polarization in monolayer GaP3 by doping TM atoms, and our work provides theoretical calculation supports for the applications of triphosphide in spintronics.
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Li, Ke Jia, Xia Xiao, and Yu Feng Jin. "Theoretical Analysis of Young’s Modulus and Dielectric Constant for Low-k Porous Silicon Dioxide Films." Key Engineering Materials 353-358 (September 2007): 2920–23. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.2920.
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Porous silicon dioxide films featuring low dielectric constant are of great scientific and commercial interest because of their outstanding potential for application to microelectronic interconnect. However, some reliability problems arise in porous SiO2 films due to their poor mechanical performance. Therefore, it is very important to understand the mechanical and electrical properties of porous SiO2 films. New 2-D models with circle pores and 3-D models with cubic pores are proposed in this work. Simulated results of porous SiO2 structures in the case of periodic and random arrangement, which are implemented through ANSYS, are also provided. Critical parameters such as Young’s modulus E and dielectric constant k of porous films are investigated. Calculation results show that dielectric constant reaches as low as 2.5 when porosity of films is about 40%, while E keeps over 3 GPa if porosity remains in the range from 30% to 40%.
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Pluijmert, Marieke, Joost Lumens, Mark Potse, Tammo Delhaas, Angelo Auricchio, and Frits W. Prinzen. "Computer Modelling for Better Diagnosis and Therapy of Patients by Cardiac Resynchronisation Therapy." Arrhythmia & Electrophysiology Review 4, no. 1 (2015): 62. http://dx.doi.org/10.15420/aer.2015.4.1.62.
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Mathematical or computer models have become increasingly popular in biomedical science. Although they are a simplification of reality, computer models are able to link a multitude of processes to each other. In the fields of cardiac physiology and cardiology, models can be used to describe the combined activity of all ion channels (electrical models) or contraction-related processes (mechanical models) in potentially millions of cardiac cells. Electromechanical models go one step further by coupling electrical and mechanical processes and incorporating mechano-electrical feedback. The field of cardiac computer modelling is making rapid progress due to advances in research and the ever-increasing calculation power of computers. Computer models have helped to provide better understanding of disease mechanisms and treatment. The ultimate goal will be to create patient-specific models using diagnostic measurements from the individual patient. This paper gives a brief overview of computer models in the field of cardiology and mentions some scientific achievements and clinical applications, especially in relation to cardiac resynchronisation therapy (CRT).
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Gao, Sumei, Quanyong Ju, and Chaowu Jin. "Support characteristics and application of permanent magnet suspension active mass drive system." International Journal of Applied Electromagnetics and Mechanics 67, no. 1 (September 2, 2021): 83–96. http://dx.doi.org/10.3233/jae-201631.
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In this paper, a kind of permanent magnet (PM) suspension active mass drive mechanism is proposed, and its structure is designed. It has the advantages of non-contact, almost zero friction, small volume, and so on. Aiming at the active driving mass mechanism of PM suspension, the unidirectional PM suspension system and bi-directional PM suspension system are designed respectively, and their analytical models are established. By analyzing and calculating the magnetic force of the unidirectional and bi-directional PM suspension system, the support coefficient of the suspension system is deduced. After theoretical analysis, the structure is simulated and verified by ANSYS MAXWELL 3D in order to determine the correctness of the analytical calculation of the model. Finally, a test device is made and experiments are carried out in the constant temperature laboratory. The experimental results show that the Nd-Fe-B PMs used in the unidirectional suspension system can provide a maximum force of 260 N, which verify the feasibility of the PM suspension active mass drive system.
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Zhou, You, Songtao Wu, Zhiping Li, Rukai Zhu, Shuyun Xie, Xiufen Zhai, Lei Lei, and Fabien Magri. "Permeability Calculation of Sand Conglomerate Reservoirs Based on Nuclear Magnetic Resonance (NMR)." Geofluids 2020 (September 28, 2020): 1–14. http://dx.doi.org/10.1155/2020/1385469.
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The concept of an intermingled fractal unit (IFU) model was first proposed by Atzeni and Pia in 2008, and their model has since been successfully applied to predict thermal conductivity, electrical conductivity, and the mechanical properties of porous media materials. This paper, based on the Pia IFU model, fits the pore size distribution spectrum to quantitatively characterize the Triassic Karamay Formation conglomerate reservoirs in the Mahu region, in the Junggar Basin of Northwest China, and makes permeability predictions using the free fluid T 2 spectrum according to the nuclear magnetic resonance (NMR) experimental data. The results show that the accuracy of the IFU model is significantly higher than that of the classic Coates and SDR models for conglomerate reservoirs with complex pore structures, indicating that this is an effective method to calculate permeability based on NMR. In addition, preliminary discussions are entered into regarding the intermingled fractal expression of the Kozeny-Carman equation and the relative permeability, in order to widen the application of the IFU model in reservoir physics. The derived expressions appear complicated in form but are straightforward to calculate and apply using computer programming since their iteration parameters are definite. The findings set out in this paper provide a valuable reference for further research of the IFU model in reservoir physics.
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Lu, Shiue Der, Meng Hui Wang, and Shih Kai Chen. "Application of chaos and extension theory to fault diagnosis of three-phase synchronous generators." Journal of Low Frequency Noise, Vibration and Active Control 39, no. 3 (February 14, 2019): 665–77. http://dx.doi.org/10.1177/1461348419829668.
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This study applied an extension algorithm combined with the Chaos Theory to the fault diagnosis of the three-phase synchronous generator. First, the three-phase synchronous generator is classified, including normal, carbon brush fault, three-phase unbalance, and insulation deterioration, and then by means of hardware measurement circuit and device, electrical signals are measured for each category and a chaotic error scatter map is built through the Chaos Theory to get the chaotic eye coordinates under specific fault categories. Next, the extension algorithm is used to carry out the correlation function and the normalization calculation, evaluating the type of fault to which it belongs. The analysis results show that the proposed method can effectively identify the fault types of three-phase synchronous generators and significantly reduce the amount of feature extraction data, so as to effectively detect the change of fault signals, allowing us to know the operation state of three-phase synchronous generators.
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Vacharakup, Somsak, Monthakarn Peerasaksophol, Thanatchai Kulworawanichpong, and Padej Pao-La-Or. "Study of Natural Frequencies and Characteristics of Piezoelectric Transformers by Using 3-D Finite Element Method." Applied Mechanics and Materials 110-116 (October 2011): 61–66. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.61.
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Piezoelectric transformers are electronic devices made from piezoelectric materials. The piezoelectric transformers as the name implied are used for changing voltage signals from one level to another. Electrical energy carried with signals is transferred by means of mechanical vibration. Characterizing in both electrical and mechanical properties leads to extensively use and efficiency enhancement of piezoelectric transformers in various applications. In this paper, study and analysis of electrical and mechanical properties in forms of potential and displacement distribution throughout the volume, respectively, are discussed and especially focused on around its natural frequency. This paper proposes a set of quasi-static mathematical model of electro-mechanical coupling for piezoelectric transformer by using a set of partial differential equations. Computer-based simulation utilizing the three-dimensional finite element method (3-D FEM) is exploited as a tool for calculation in two purposes. The first use is developed the 3-D FEM for identifying its natural frequencies while the second use is for visualizing potentials and displacements distribution within the piezoelectric transformer. The computer simulation based on the use of the FEM has been developed in MATLAB programming environment. In addition, which satisfactory results of natural frequencies are compared with those obtained from the experiment and the accuracy of 3-D FEM model is confirmed.
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Hadim, A., A. T. Chang, A. Chu, and A. Yskamp. "An Interfacing Software Package for Thermal Analysis: Application to Microelectronics." Journal of Electronic Packaging 111, no. 1 (March 1, 1989): 54–60. http://dx.doi.org/10.1115/1.3226509.
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A software package called: INterfacing Software for Thermal ANalysis (INSTAN) is developed to interface finite element general purpose programs with finite-difference thermal network analyzers for detailed analysis of complex thermal problems. The finite element mesh is used to generate the thermal network representation of the problem. INSTAN performs automatically the thermal network calculations and generates a complete input file for the thermal analysis program. The INSTAN software package is a powerful modeling tool which uses the preprocessing and postprocessing features available in a finite element program. It has also the flexibility and heat transfer calculation capabilities of a finite-difference program. It can handle problems with three-dimensional irregular geometries, time and temperature dependent properties, and anisotropic materials. The software possesses enhanced capabilities that make it suitable for thermal analysis of microelectronic equipment.
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Androsov, Nikolay Nikolaevich, Igor Stanislavovich Tsikhalevskiy, and Konstantin Andreevich Vakhrushev. "Analysis of possibility of application of induction motors with various number of phases." Transport of the Urals, no. 1 (2020): 70–73. http://dx.doi.org/10.20291/1815-9400-2020-1-70-73.
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The paper analyses operational indicators of electric locomotives with commutator and induction motor traction motors. It is established that, due to the inherent limitations of the commutator motors, electric locomotives can work with rated power in speed range of 51.2–79 km/h, at maximum speed of 100 km/h power doesn’t exceed 68 % of rated. In order to increase the energy efficiency the authors have proposed to widen by several times the speed range at a constant rated power and reduce as much as possible operation at overload modes. Induction motors have significantly wider ranges for electromagnetic, thermal and mechanical loads. The calculation of losses in converter of phases and frequency for induction motors with various number of phases showed that total losses of three-phase motor reach 1.9 %, losses of motor with even number of phases doesn’t exceed 0.8 %. As a result, it is preferable to use traction motors with 8-phase winding.
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Guyenot, M., M. Reinold, Y. Maniar, and M. Rittner. "Advanced wire bonding for high reliability and high temperature applications." International Symposium on Microelectronics 2016, no. 1 (October 1, 2016): 000214–18. http://dx.doi.org/10.4071/isom-2016-wa51.
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Abstract The next generation of switches for power electronic will be based on white band gap (WBG) semiconductor GaN or SiC. This materials supports higher switching current and high frequency. White band gap semiconductors enables higher application temperature. Certainly, high temperature capability is also to discuss in combination with high number of thermal cycles. For a frame module concept shows these paper a comparison of different joining techniques with the focus on the reliability issue on wire and ribbon bonding. Beside to the 1000 passive thermal cycles from −40°C to +125°C there are active thermals cycles for technology qualification required [3]. Depending on the application and mission profile a high thermal cycling capability is necessary. For this reason, new high temperature joining techniques for die attach, e.g. Silver sintering or diffusion soldering, were developed in the recent past [4]. All of this new joining techniques focusing on higher electrical, thermal and thermo-mechanical performance of power modules. By using an optimized metallization system for the WBG the numbers of thermal cycles can be increased and the maximum operating temperature advanced up to 300°C. In these new temperature regions silicon semiconductors will be substituted by WBG semiconductors. The present work shows an active power cycling capability of different wire and ribbon bonds and the failure mechanism will be discussed. A calculation model explained the reliability for the different wire diameter and the impact of bonding materials. This reliability calculation explain the thermo-mechanical effects and based on materials and geometry data and is not optimized for evidence. Through these physical background understanding more than 1.000.000 thermal cycles with a 150 K temperature swing from +30°C to +180°C are now possible. These is a the basic knowledge for a design for reliability based on current, mission profile and reliability optimization for future high end applications with wire or ribbon bonding technique.
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Kwaśniewski, Tomasz, and Marian Piwowarski. "Design Analysis of Hybrid Gas Turbine‒Fuel Cell Power Plant in Stationary and Marine Applications." Polish Maritime Research 27, no. 2 (June 1, 2020): 107–19. http://dx.doi.org/10.2478/pomr-2020-0032.
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AbstractThe paper concerns the design analysis of a hybrid gas turbine power plant with a fuel cell (stack). The aim of this work was to find the most favourable variant of the medium capacity (approximately 10 MW) hybrid system. In the article, computational analysis of two variants of such a system was carried out. The analysis made it possible to calculate the capacity, efficiency of both variants and other parameters like the flue gas temperature. The paper shows that such hybrid cycles can theoretically achieve extremely high efficiency over 60%. The most favourable one was selected for further detailed thermodynamic and flow calculations. As part of this calculation, a multi-stage axial compressor, axial turbine, fuel cell (stack) and regenerative heat exchanger were designed. Then an analysis of the profitability of the installation was carried out, which showed that the current state of development of this technology and its cost make the project unprofitable. For several years, however, tendencies of decreasing prices of fuel cells have been observed, which allows the conclusion that hybrid systems will start to be created. This may apply to both stationary and marine applications. Hybrid solutions related to electrical power transmission, including fuel cells, are real and very promising for smaller car ferries and shorter ferry routes.
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PODDUBKO, Sergey N., Nikolay N. ISHIN, Arkadiy M. GOMAN, Andrey S. SKOROKHODOV, and Vladimir V. SHPORTKO. "ENERGY EFFICIENCY OF GEARBOXES APPLICATION IN POWER UNITS OF ELECTRIC VEHICLES." Mechanics of Machines, Mechanisms and Materials 3, no. 56 (September 2021): 5–12. http://dx.doi.org/10.46864/1995-0470-2021-3-56-5-12.
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With all advantages, electric vehicles have a significant disadvantage — a relatively small driving range on a single charge of the traction battery compared to cars using hydrocarbon fuel. The solution to the issue is to choose a rational structural scheme of an electromechanical power unit to obtain its high energy efficiency regardless of the operating conditions. A significant number of electric vehicles produced today either do not contain gearboxes or contain single-speed reducers. The use of a multi-speed gearbox solves the problem of adapting the working processes of a traction electric motor to the loading conditions, bringing its efficiency as close as possible to the range of highly efficient values. Calculated estimation of energy consumption of the MAZ-4381EE electric delivery truck is carried out in the paper for various versions of the mechanical part of power unit: without a reducer, with the use of a reducer and two types of two-speed gearboxes (shaft and shaft-planetary). The evaluation is made based on consideration of the European test driving cycle NEDC, taking into account the use of efficiency maps of the traction induction electric motor. The calculation results showed that the use of two-speed gearboxes can reduce the total energy consumption by more than 1.8 times compared to a power unit with a high-torque motor and without a gearbox.
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Sieklucki, Grzegorz. "Optimization of Powertrain in EV." Energies 14, no. 3 (January 30, 2021): 725. http://dx.doi.org/10.3390/en14030725.
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The method for preliminary powertrain design is presented in the paper. Performance of the EV is realized by motor torque–speed curve and gear ratio optimization. The typical two-zone mechanical characteristic of a PMSM traction motor is included in the optimization program. The longitudinal vehicle model is considered in the paper. Some examples try to show the calculation possibilities in application to existing vehicles: Tesla Model S and Mini Cooper SE.
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Derepa, A. V., A. G. Leiko, and O. N. Pozdniakova. "PHYSICAL FIELDS OF CIRCULAR CYLINDRICAL PIEZOCERAMIC RECEIVER IN PRESENCE OF A FLAT ACOUSTIC SOFT SCREEN." Devices and Methods of Measurements 8, no. 2 (June 9, 2017): 168–76. http://dx.doi.org/10.21122/2220-9506-2017-8-2-168-176.
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System in the form of a circular cylindrical piezoceramic transducer near a flat acoustic screen was analyzed. The aim of the work was to solve the problem of receiving plane sound waves by «cylindrical piezoceramic transducer – flat acoustically soft screen» system.Considered system was characterized by a violation of the radial symmetry of the radiation load of the transducer while maintaining the radial symmetry of the electric load. At the same time, the energy perceived by the system under consideration is distributed between all modes of oscillation of the transducer, while the conversion of mechanical energy into electric is realized only at zero mole of oscillations.Special attention was paid to the method of coupled fields in multiply connected domains using the imaging method. The design model of the «transducer–creen» system was formulated taking into account the interaction of acoustic, mechanical and electric fields in the process of energy conversion, the interaction of a cylindrical transducer with a flat screen and the interaction of a converter with elastic media outside and inside it. The physical fields of the system under consideration were determined by following solutions: the wave equation; equations of motion of thin piezoceramic cylindrical shells in displacements; equations of stimulated electrostatics for piezoceramics for given boundary conditions, conditions for coupling fields at interfaces and electrical conditions.A general conclusion was made concerning solving of an infinite system of linear algebraic equations with respect to the unknown coefficients of the expansion of the fields. As an example of the application of the obtained relations, a calculation was made and an analysis of the dependences of the electric fields of the system under consideration for various parameters of its construction on the direction of arrival on the plane wave system was conducted.
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Rogova, Elena, Gabriel Lodewijks, and Eduardo Calixto. "Reliability Assessment of Safety Systems with Asymmetrical Redundancy Architecture." International Journal of Reliability, Quality and Safety Engineering 25, no. 02 (March 6, 2018): 1850006. http://dx.doi.org/10.1142/s0218539318500067.
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Application of an M-out-of-N redundancy architecture is a well-known measure for improving the reliability of safety systems. Most scientific papers addressing the reliability assessment of such systems consider a conventional homogeneous M-out-of-N redundancy architecture that is performed for identical channels. However, often in practice, an M-out-of-N redundancy architecture does not have identical channels. Reliability assessment of such heterogeneous systems (electrical/electronic and mechanical) with nonidentical channels and a combination of constant and nonconstant failure rates is considered in this paper. Such type of M-out-of-N redundancy architecture is introduced in this research as “asymmetrical redundancy”. It can be used for enhancing the reliability of old mechanical systems or for reducing mutual influence of channels and increase of diagnostic coverage. This paper also presents a new “window-based Markov method” for PFD[Formula: see text] (average probability of failure on demand) and PFH (average frequency of dangerous failures) calculation for systems with an asymmetrical redundancy architecture and compares the results with those obtained by using the steady-state semi-Markov method and Monte-Carlo simulation. The applicability of the developed method is demonstrated in a simple case study.
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Ćosović, Vladan, Duško Minić, Milena Premović, Dragan Manasijević, Aleksandar Đorđević, Dušan Milisavljević, and Aleksandar Marković. "The influence of chemical composition on microstructure, hardness and electrical conductivity of Ag-Bi-In alloys at 100 °C." Metallurgical and Materials Engineering 23, no. 1 (March 31, 2017): 65–82. http://dx.doi.org/10.30544/265.
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Considering possible applications and scarceness of literature data, Ag-Bi-In system was investigated in terms of microstructure, mechanical and electrical properties of ternary alloys from an isothermal section at 100oC. Based on the experimentally obtained results hardness and electrical conductivity of all ternary alloys from the ternary Ag-Bi-In system at 100oC were predicted. In addition, the selected isothermal section was further thermodynamically assessed and experimentally studied using scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS), X-ray powder diffraction (XRD) analysis and light optical microscopy (LOM). Phase transition temperatures of alloys with overall compositions along vertical sections x(Ag)=0.5 as well as liquidus temperatures were experimentally determined by DTA. The experimentally obtained results were compared with literature data and with the results of thermodynamic calculation of phase equilibria based on CALPHAD method and corrected data for Ag-In binary system. Calculated liquidus projection, invariant equilibria and phase diagram of the Ag-Bi-In ternary system are presented as well.
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Belonozhko, Pavel P., and Yury V. Berchun. "Learning to Model the Dynamics of Mechanical Systems with the Method of Solving Educational and Research Problems." ITM Web of Conferences 35 (2020): 04003. http://dx.doi.org/10.1051/itmconf/20203504003.
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The methodological features of using software systems for modeling the dynamics of mechanical systems for solving educational research problems are considered. The traditionally established approach to studying the foundations of modeling the dynamics of technical systems is largely based on mastering the corresponding mathematical tools. With regard to modeling the dynamics of systems of solids, the mentioned approach involves, first of all, the development of skills in the preparation of ordinary differential equations (ODEs). At the same time, the formation of a mechanical calculation scheme as an «object of application of mathematics» becomes a natural stage of mathematical research, and the selection of simplifying assumptions that allow one or another idealization to correspond to a real object is carried out consciously taking into account the desire for certain internal properties of the mathematical model (for example, type and order of the ODE system). An important feature of modern systems for modeling the dynamics of solid’s systems is the ability to describe the object under study directly in terms of the subject area. This feature provides an increase in the effectiveness of modeling in solving design and engineering and scientific research problems and allows you to save a qualified specialist from a laborious routine. At the same time, as experience shows, in the process of solving educational and research problems, due to the mentioned features of modern software, students have certain difficulties in mastering the fundamental conceptual base of the corresponding discipline (physics, electrical engineering, theoretical mechanics, theory of automatic control, fundamentals of computer aided design). The article gives an example of an educational research task focused on overcoming these difficulties.
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Iora, P., and S. Campanari. "Development of a Three-Dimensional Molten Carbonate Fuel Cell Model and Application to Hybrid Cycle Simulations." Journal of Fuel Cell Science and Technology 4, no. 4 (April 14, 2006): 501–10. http://dx.doi.org/10.1115/1.2756850.
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In this paper, a three-dimensional finite volume model of a molten carbonate fuel cell (MCFC) is presented. The model applies a detailed electrochemical and thermal analysis to a planar MCFC stack of given geometry and assigned input flows conditions, material properties and assigned external heat losses, calculating global energy balances and reactant utilization, as well as internal temperature and chemical composition profiles, pressure profiles, polarization losses, and current density and voltage distribution over the stack. The model is calibrated on the available data for an experimented MCFC stack manufactured by Ansaldo Fuel Cells. The comparison of 2D versus 3D simulations is first discussed, showing the importance of the 3D model for an accurate analysis of real stack operation under significant heat loss conditions, but also showing the mutual influence of heat transfer between adjoining cells and evidencing the variable electrical performances between different cells of the same stack. As a counterpart, application of the 2D model, which takes advantage by much shorter calculation time while keeping a reasonable accuracy in the overall energy balances, is anyway indicated for complex cycle analysis and cycle optimization, where a complete 3D stack analysis may be limited to selected cases. Then, the model is applied to the off-design analysis of hybrid cycles based on a recuperated gas turbine arrangement where variable pressure ratios and fuel supply conditions are assumed for the fuel cell. The effects of the operating pressure and of the adoption of different fuel compositions are considered, with a cycle layout that may include natural gas reforming or is directly fed by a syngas provided by an external source, simulating different fuel feedstocks (e.g., coal gasification). Complete results are presented, in terms of fuel cell and overall cycle performances.
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Shimose, Shigeru, Kanjuro Makihara, and Junjiro Onoda. "Comparison of Analog and Digital Self-Powered Systems in Multimodal Vibration Suppression." Smart Materials Research 2012 (February 21, 2012): 1–9. http://dx.doi.org/10.1155/2012/287128.
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This paper compares our analog and digital self-powered systems for vibration suppression, and shows experimental results of multimodal vibration suppression for both self-powered systems. The experimental results are evaluated in light of the damping performance and adaptability under various vibrational conditions. We demonstrate various examples of our innovative vibration suppression method, called “digital self-powered.” Proper status switching of an electric circuit made up of an inductor and a selective switch connected to a piezoelectric transducer attenuates the vibrations. The control logic calculation and the switching events are performed with a digital microprocessor that is driven by the electrical energy converted from the mechanical vibration energy. Therefore, this vibration suppression system runs without any external power supply. The self-powering feature makes this suppression method useful in various applications. To realize an ideal vibration suppression system that is both self-powered and effective in suppressing multimode vibration, sophisticated control logic is implemented in the digital microprocessor. We demonstrate that our digital self-powered system can reduce the vibrational displacements of a randomly excited multimodal structure, by as much as 35.5%.
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Lu, Nianduan, Wenfeng Jiang, Quantan Wu, Di Geng, Ling Li, and Ming Liu. "A Review for Compact Model of Thin-Film Transistors (TFTs)." Micromachines 9, no. 11 (November 15, 2018): 599. http://dx.doi.org/10.3390/mi9110599.
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Thin-film transistors (TFTs) have grown into a huge industry due to their broad applications in display, radio-frequency identification tags (RFID), logical calculation, etc. In order to bridge the gap between the fabrication process and the circuit design, compact model plays an indispensable role in the development and application of TFTs. The purpose of this review is to provide a theoretical description of compact models of TFTs with different active layers, such as polysilicon, amorphous silicon, organic and In-Ga-Zn-O (IGZO) semiconductors. Special attention is paid to the surface-potential-based compact models of silicon-based TFTs. With the understanding of both the charge transport characteristics and the requirement of TFTs in organic and IGZO TFTs, we have proposed the surface-potential-based compact models and the parameter extraction techniques. The proposed models can provide accurate circuit-level performance prediction and RFID circuit design, and pass the Gummel symmetry test (GST). Finally; the outlook on the compact models of TFTs is briefly discussed.
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Qureshi, Muhammad Waqas, Xinxin Ma, Guangze Tang, and Ramesh Paudel. "Structural Stability, Electronic, Mechanical, Phonon, and Thermodynamic Properties of the M2GaC (M = Zr, Hf) MAX Phase: An ab Initio Calculation." Materials 13, no. 22 (November 16, 2020): 5148. http://dx.doi.org/10.3390/ma13225148.
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The novel ternary carbides and nitrides, known as MAX phase materials with remarkable combined metallic and ceramic properties, offer various engineering and technological applications. Using ab initio calculations based on generalized gradient approximation (GGA), local density approximation (LDA), and the quasiharmonic Debye model; the electronic, structural, elastic, mechanical, and thermodynamic properties of the M2GaC (M = Zr, Hf) MAX phase were investigated. The optimized lattice parameters give the first reference to the upcoming theocratical and experimental studies, while the calculated elastic constants are in excellent agreement with the available data. Moreover, obtained elastic constants revealed that both the Zr2GaC and Hf2GaC MAX phases are brittle. The band structure and density of states analysis showed that these MAX phases are electrical conductors, having strong directional bonding between M-C (M = Zr, Hf) atoms due to M-d and C-p hybridization. Formation and cohesive energies, and phonon calculations showed that Zr2GaC and Hf2GaC MAX phases’ compounds are thermodynamically and dynamically stable and can be synthesized experimentally. Finally, the effect of temperature and pressure on volume, heat capacity, Debye temperature, Grüneisen parameter, and thermal expansion coefficient of M2GaC (M = Zr, Hf) are evaluated using the quasiharmonic Debye model from the nonequilibrium Gibbs function in the temperature and pressure range 0–1600 K and 0–50 GPa respectively.
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Liu, Haiyan, Qingsheng Zhu, Li Zhang, Zhongguang Wang, and Jian Ku Shang. "Enhanced stress relaxation of Sn–3.8Ag–0.7Cu solder by electrical current." Journal of Materials Research 25, no. 6 (June 2010): 1172–78. http://dx.doi.org/10.1557/jmr.2010.0143.
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The stress relaxation responses of the Sn–3.8Ag–0.7Cu joints following exposure to electrical currents were examined to investigate the effect of electromigration on the reliability of solder joints. It was found that the stress relaxation rate was enhanced for the Sn–3.8Ag–0.7Cu solder joints subjected to a current density of 2 × 104 A/cm2. Sn hillock formation was observed in situ on the surface of the solder joint and the increase of the hillock volume was obtained as a function of the current application time. Analysis of the vacancy flux indicated that the variations of the vacancy concentration with the electromigration time from the calculations agreed with the growth kinetics of the hillocks observed in the experiments. By modeling the stress relaxation as a climb-assisted dislocation glide process, it is shown that the vacancy accumulation induced by electromigration enhanced the dislocation climb rate, resulting in a large increase of the stress relaxation rate.
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Smolentsev, E. V., M. V. Kondratev, E. V. Pavlov, and V. V. Kuts. "Non-abrasive Finishing of Mating Surfaces of Machine Parts Using Mixed Techniques with Electromagnetic Fields Application." Proceedings of the Southwest State University 24, no. 3 (December 6, 2020): 51–65. http://dx.doi.org/10.21869/2223-1560-2020-24-3-51-65.
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In various branches of mechanical engineering, faucets, valves, gate valves and other shut-off devices are manufactured and used. Their main purpose is to regulate the flow rate and direction of flows of liquid and gas media. Features of such products in the aerospace and petrochemical engineering are special strict requirements due to the specificity of their operation. These include, for example, high pressure, resistance to aggressive, fire-and explosive environments, leaks of which are unacceptable according to safety rules and environmental legislation. The design of such products, as a rule, assumes high requirements for accuracy and roughness, especially at the interface of parts, high strength in case of impact pulse effects of the fluids in them. To ensure the above characteristics, finishing abrasive treatment is most commonly used, which can result in the effect of impregnation of the surfaces of products, which will negatively affect the useful life and performance indicators of the mating surfaces. At the same time, it is obvious that mechanical finishing without any use of abrasives is extremely difficult and time-consuming. The authors of the article suggest elimination of the negative effect of impregnation by means of mixed machining techniques with the application of electromagnetic fields. Purpose. The purpose of the work is to develop a technology for non-abrasive finishing of machine parts by developing a model that allows selection or calculation of the production modes of gapless mating parts of locking devices applied in various industries. Methods. The method of the research is the use of the scientific basis of mixed machining techniques, the theory of mass transfer in electrical machining, the fundamental foundations of mechanical engineering technology, modern methods for studying characteristics at the final stages of machining, modern measuring tools, special technological equipment, as well as computer technologies. Results. As a result of the research, new technique and devices were developed. This made it possible to implement a non-abrasive finishing operation of the mating surfaces of parts made of metal materials, the processing of which by mechanical methods is difficult. Conclusion. As a result of the conducted research, it became possible to obtain high-quality high-resource gapless locking products and to reduce labor intensity of the finishing operation up to 5 times and preparation for the production up to 2 times.
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Eltaief, Ameni, Sébastien Remy, Borhen Louhichi, Guillaume Ducellier, and Benoit Eynard. "Comparison between CAD models using modification ratio calculation." International Journal of Computer Integrated Manufacturing 32, no. 10 (September 17, 2019): 996–1008. http://dx.doi.org/10.1080/0951192x.2019.1667030.
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Vandevelde, Bart, Eric Beyne, Dirk Vandepitte, and Martine Baelmans. "Analytical Thermo-Mechanical Model for Non-Underfilled Area Array Flip Chip Assemblies." Journal of Electronic Packaging 126, no. 3 (September 1, 2004): 351–58. http://dx.doi.org/10.1115/1.1772416.
Full textAbstract:
An analytical model is derived for the calculation of thermo-mechanical induced stresses in area array flip chip assemblies. This analytical model is based on structural mechanics and has the ability to characterize the nature and to estimate the magnitude of the induced stresses. The extension of this model compared to existing procedures is its applicability to area array systems, which behave significantly different from peripheral assemblies. The model is compared to finite element simulations. The model calculates accurately the forces and bending moments acting on the flip chip connections. The transformation of these forces and moments into stresses is less accurate as the model does not include stress concentrations near the corners. The model simulates very well the different parameter trends such as chip size and is therefore well suited for understanding parameter sensitivity studies.