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The transmission capacity of overhead power lines depends on the temperature. Power cores temperature is determined by the weather conditions (sun, wind, temperature) and the load current magnitude. Due to their high performance characteristics insulated wires are widely used in the power industry. Based on the heat conductivity differential equation we developed a generalized mathematical model for...
In this paper, an operator-based robust perfect control for nonlinear semiconductor refrigeration device with uncertainties is considered. For the research about the properties of the semiconductor refrigeration, an aluminum plate with Peltier device is very representative. So, the perfect tracking control performance is investigated by using this device. The robust right coprime factorization approach...
A 1-D model for the simulation of transition from glow microdischarge to arc discharge with a thermionic cathode was built using COMSOL Multiphysics. The extended fluid model was coupled with the gas heating equation for the self-consistent simulation of discharge at atmospheric pressure in a wide range of currents. Both the secondary electron emission and the thermionic emission were taken into account...
Thin oxide films are dominantly used as insulating materials in a wide range of CMOS electronic devices. Continuous scaling, governed by Moores Law, dictates that the thickness of oxides materials could be as thin as a few nanometers. Consequently, a generation of oxide defects, through field-driven and thermal-driven processes, presents a serious reliability challenge. On the other hand, a controllable...
Thermal circuit models are based on the analogy between heat transfer and current flow equations. A thermal circuit model is extracted from a solid model of the package assembly by means of a mathematical model order reduction (MOR) algorithm. This algorithm automatically generates a SPICE netlist that can be used with standard analog circuit simulator, for simulation of transient operating conditions...
In this paper, a closed-loop strategy for controlling the transient regime of Marangoni flows and thus to selectively manipulate and separate micro-particles is reported. Marangoni flows were generated by an infrared laser as a heat source. Simulations of the transient regime of Marangoni flows were performed with COMSOL Multiphysics to analyze the temperature field and velocity profile. The convection...
Paper is devoted to research of start-up modes of high-voltage asynchronous motor multi-stage blower. To reduce a voltage dips during starting of such motors are widely used soft starters based on a thyristor voltage converters. For high inertia drives with a long start-up mode an acceleration can be accompanied by overheating of the motor windings. In this paper we evaluated the possibility of reducing...
The significant continuous increase in the power consumption of data centers, brought about by the adoption of cloud computing, is a major social problem. Moreover, the demand for data centers is expected to grow owing to the increasing requirement for data processing related to Internet of Things (IoT) applications. Consequently, reducing the power consumption of data centers has become an urgent...
The purpose of this paper is to show the capability of the TLM method to handle temperature rising in strong heterogenous biological tissues exposed to various RF sources such as incident plane waves or near fields radiated by a PIFA antenna. The SAR and thermal distributions simulated in the head of the human Duke model are provided and compared with those obtained with the commercial software CST...
Safety is the first priority of any energy storage system. In this paper, safety studies are performed on three types of 2.6 Ah lithium ion batteries: high-drain thin-electrode battery (Cell 1), cellphone battery (Cell 2) and 18650 type battery (Cell 3), which are different in geometry and internal parameters. The batteries' discharge behaviors are tested on a battery analyzer, and their performances...
This paper studies optimal time-bounded control in a simple subclass of linear hybrid systems, which consists of one continuous variable and global constraints. Each state has a continuous cost attached to it, which is linear in the sojourn time, while a discrete cost is attached to each transition taken. We show the corresponding decision problem to be NP-complete and develop an FPTAS for finding...
Natural convection cooling offers advantages such as low cost, high reliability, noiseless operation and positioning independent from other cooling circuits. Since the main disadvantage is a relatively low heat transfer, an analytic model is required to efficiently design natural convection heat sinks according to the applied design constraints. This paper describes a natural convection thermal model...
This paper represents the thermal behavior of a lithium-ion capacitor. In this study, an extended parameter analysis has been realized for observing the thermal behavior when applying dedicated load profiles. Based on the performed analysis, an electro-thermal model and a 3D thermal model have been developed for future optimization of a thermal strategy. The model has been implemented using COMSOL...
This paper presents a complementary, alternative teaching and learning methodology based on the use of the finite element method to illustrate mathematical models and to explore their (numerical) solutions in the context of vector calculus properties understanding. This methodology is illustrated via a set of examples focused on specific engineering problems, but its scope can also be widened to other...
Achieving mathematical model and simulation is essential in the design of complex installations. This allows analysis of different operating modes and behavior evaluation system. This enables notification of possible errors and their correction, avoiding additional costs involved in achieving and testing facility in real conditions. Some operating modes may be degraded modes would be very difficult...
This article uses a two-dimensional phenomenological model representing the dynamic behaviour of a clinker kiln, and includes another model to estimate the height of the solid material (crude) inside the kiln. These models are parameterized according to design specifications and operating conditions of a real industrial kiln, which belongs to a cement production plant. The whole model consists of...
In this paper, thermal slide rheostats of cylinder and thermal circuit network based on them have been studied. The object here is abstracted from part of cylinder in swashplate axial piston pump (SAPP) in electro-hydrostatic actuator (EHA). Obviously, this object occupies asymmetry of thermal processes and medium alternation in circumferential direction. As a result, a three-dimension thermal circuit...
Using the nonequilibrium Green's function method, the problem of thermal relaxation of systems interacting with a heat bath is investigated. We apply this method to the harmonic oscillator interacting with a heat bath which consists of many harmonic oscillators. Using with the Keldysh nonequilibrium Green function technique we derive expressions for the the absorption and emission spectra. We also...
For easy removal of cylindrical items from the shaft, they are heated on their external cylindrical surface for thermal expansion. The best result is obtained if the temperature drop is highest on the separation from shaft air layer. In the paper, considering a suddenly occurring constant high temperature on the external cylindrical surface of the homogeneous item and the shaft with the same thermal...
We present a comprehensive theoretical and numerical study of the stochastic rotational motion of a high anisotropic ferromagnetic nanoparticle in a viscous carrier driven by a time-periodic field. The effects of energy absorption of circularly and linearly polarized fields are analyzed. The analytical expressions and numerical data for the probability density and the power loss are compared for different...
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