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Electromagnetic Transients Analysis
Published in Antonio Gómez-Expósito, Antonio J. Conejo, Claudio A. Cañizares, Electric Energy Systems, 2018
Juan A. Martínez-Velasco, José R. Martí
The calculation of matrices [Z] and [Y] uses cable geometry and material properties as input parameters. In general, it is necessary to specify: Geometry: location of each conductor (x–y coordinates); inner and outer radii of each conductor; burial depth of the cable system.Material properties: resistivity, ρ, and relative permeability, μr, of all conductors (μr is unity for all nonmagnetic materials); resistivity, ρ, and relative permeability of the surrounding medium, μr; relative permittivity of each insulating material, ɛr.
Light, Waves, and Rays
Published in Vincent Toal, Introduction to Holography, 2011
In the first half of the twentieth century, a great deal of research effort was expended on finding the atomic and molecular structure of a vast number of materials, crystalline materials in particular, that is, to identify the constituent atoms of a given substance and their arrangement with respect to one another in space. This information is of crucial importance in understanding material properties required for the design of new materials, including chemicals, engineering materials, biomaterials, and pharmaceuticals. The main tool used was X-rays, which consist of electromagnetic radiation of wavelength much shorter than that of visible light, of the order of nanometers in fact, which is typical of the interatomic spacing in most crystalline materials. This means that many materials act like 3-D gratings producing diffraction patterns, which, upon careful analysis, enable us to work back to the molecular structure of the material. One of the greatest achievements that resulted was the discovery of the structure of DNA by Crick, Watson, and Wilkins using X-ray diffraction patterns of DNA obtained by Franklin.
Power Grid Design
Published in Charles J. Alpert, Dinesh P. Mehta, Sachin S. Sapatnekar, Handbook of Algorithms for Physical Design Automation, 2008
With the above understanding in place, let us consider the sources of variability that would impact the performance of a power grid. Such sources include Variations in the electrical material properties, for example, material resistivity, insulator die-electric constant, etc. Let us denote these by category A.Variations in the horizontal geometry of the power grid wires, which will naturally occur in the semiconductor manufacturing process and arise primarily from the lithography and etch processes. We denote these by category B.Variations in the vertical geometry of the power grid wires, which arise primarily from the chemical–mechanical polishing (CMP) process. We denote these by category C.Variations in the loading of the power grid. These are caused by two possible sources: (1) lack of complete knowledge of the operational characteristics of the integrated circuit connected to the power grid (e.g., not knowing how active a certain part of the circuit is likely to be), and (2) the impact of manufacturing variations on the power dissipated by the circuit (e.g., the impact of MOSFET channel length fluctuations on the leakage current of the circuit). We denote these by category D.
An analytical approach to geometrically nonlinear free and forced vibration of piezoelectric functional gradient beams resting on elastic foundations in thermal environments
Published in Mechanics of Advanced Materials and Structures, 2021
Yassine El Khouddar, Ahmed Adri, Omar Outassafte, Said Rifai, Rhali Benamar
Nonlinear free and forced vibration analyses have been presented for clamped piezoelectric FGM beams resting on elastic foundations and subjected to the combined action of a transverse dynamic excitation load and a thermal load. Thermal conduction and temperature-dependent material properties are taken into account. The formulations are based on the Euler–Bernoulli beam theory and the general nonlinear Von-Karman equations, and include thermo-piezoelectric effects. In addition, an analytical solution has been proposed using the second formulation and multimodal techniques approximated around the dominant mode. A parametric study for piezoelectric FGM beams with different volume fraction index values, different elastic foundation coefficients and different dynamic and thermal loading conditions was carried out. The numerical results show that the variation of temperature and volume fraction index causes the curves of frequency ratios to vary from nonlinear to linear as a function of dimensionless amplitude. Moreover, the effects of the Winkler and Pasternak foundation coefficients are significant on the free dynamic behavior of the piezoelectric FGM beam. The results also confirm that the effect of the volume fraction index on the frequency response behaviour is relatively small. However, the temperature field and the distributed or concentrated harmonic excitation force have a very significant effect on the frequency response behaviour. In addition, the results presented show that the effect of the nonlinear foundation coefficient is significantly larger than the Winkler and Pasternak foundation coefficients at higher response amplitudes.
Physics-based simulation ontology: an ontology to support modelling and reuse of data for physics-based simulation
Published in Journal of Engineering Design, 2019
Hyunmin Cheong, Adrian Butscher
Material properties characterise a material substance, which in turn affect how a material entity made of the material substance physically behaves under some physical processes. PSO: material property = def. a BFO: quality that can be measured to identify the physical characteristics of a PSO: material substance.
The effect of aspect ratio on PCM melting behaviour in rectangular enclosure
Published in International Journal of Sustainable Engineering, 2021
F. A. Hamad, E. Egelle, S. Gooneratne, P. Russell
The transient melting/solidification model was chosen for all cases. The material properties such as specific heat capacity, thermal conductivity and viscosity were included and considered as functions of temperature. The boundary conditions were set at 353 K for the hot side and 292 K for the opposite cold side. The rest of the sides were modelled as being adiabatic by setting the heat flux at the wall equal to zero.