Thermal deformation is a nonlinear dynamic phenomenon and is one of the significant factors for the accuracy of machine tools. In this study, a dynamic feed-forward neural network model is built to predict the thermal deformation of machine tool. The temperatures and thermal deformations data at present and past sampling time interval are used train the proposed neural model. Thus, it can model...

cp heat capacity dx distance between two points after time t dX original infinitesimal distance between two points D stretching tensor Di dissipation number ĝ gravity vector h depth of convecting layer H(r) two-particle correlation function P dynamic pressure Ra thermal Rayleigh number t time T temperature ui components of the velocity tensor v velocity w upward velocity a thermal expansivity _...

This work shows results of dynamic lumpedelement (LE) thermal modeling of power AlGaN/GaN HEMTs. A realistic 3D structure including top-side metals, GaN-Si thermal boundary resistance, die-attach, and source via hole is modeled using a finite-element (FE) tool, and the results are used to develop simplified LE dynamic thermal models. We show that the LE models can match the FE data with excelle...

Electric and Electro-Hydraulic Power Steering Systems (EPS / EHPS) are gaining more and more momentum. They have substantial advantages over conventional hydraulic steering systems. In particular, EPS can improve comfort, safety and energy-efficiency of any car. The market share of these systems increases every year. The typical core component of an EPS system is a three phase brushless electri...

Financial intermediaries, such as credit rating agencies, have an incentive to maintain a public reputation for credibility amongst investors. However, in a market where credit rating agencies are interacting repeatedly with only a few issuers (sellers), they also have an incentive to develop a second, private reputation for leniency. We develop a dynamic model that analyzes how credit rating a...

Graphene oxide was prepared using modified Hummers method. Stable ethylene-glycol nanofluids containing graphene oxide nanosheets were provided. Nd: YAG pulsed laser was applied to prepare reduced nanofluids. Experimental results revealed that thermal conductivity of the nanofluids is increased with increasing the concentration of graphene oxide (GO) in ethylene glycol. The enhancement ratio of...

To exploit additional capacity on legacy transmission assets, network owners have developed a variety of techniques to support real-time thermal rating (RTTR) overhead lines so as get the maximum possible within their operating range. Most RTTR are inferred from effective weather conditions (EWCs) that used assess equilibrium conductors indicated by measured temperature <inline-formula xmlns:mm...