Search results for "Thermodynamics"
showing 10 items of 2774 documents
Atmospheric correction for land surface temperature using NOAA-11 AVHRR channels 4 and 5
1991
Abstract In this work, a theoretical model that permits relating the land surface temperature with the temperatures measured by thermal infrared sensors has been developed. The model has been derived by linearization of Planck's function and atmospheric trasmittance. In this way a split-window equation is obtained, which depends on atmospheric water vapor, viewing angle, and channel surface emissivities. Simulations of satellite measurements of land surface temperatures are made using the atmospheric transmittance-radiance model LOWTRAN-7 for NOAA-11 AVHRR Channels 4 and 5. From these simulations the accuracies of linearizations have been checked. The dependence of the split-window coeffici…
Mathematical modelling of alternating electromagnetic and hydrodynamic fields, induced by bar type conductors in a cylinder
2009
The heating of buildings by ecologically clean and compact local devices is an interesting and actual problem. One of the modern areas of applications developed during last ten years is an effective usage of electrical energy by alternating current to produce heat energy. This work presents the mathematical model of one of such devices. It is a finite cylinder with viscous incompressible liquid and with metal electrodes of the form of bars placed parallel to the cylinder axis in the liquid. These conductors are connected to the alternating current. First published online: 14 Oct 2010
An atlas- and data-driven approach to initializing reaction-diffusion systems in computer cardiac electrophysiology
2016
The cardiac electrophysiology (EP) problem is governed by a nonlinear anisotropic reaction-diffusion system with a very rapidly varying reaction term associated with the transmembrane cell current. The nonlinearity associated with the cell models requires a stabilization process before any simulation is performed. More importantly, when used in a 3-dimensional (3D) anatomy, it is not sufficient to perform this stabilization on the basis of isolated cells only, since the coupling of the different cells through the tissue greatly modulates the dynamics of the system. Therefore, stabilization of the system must be performed on the entire 3D model. This work develops a novel procedure for the i…
Modelling of thermal stresses in bearing steel structure generated by electrical current impulses
2018
This work is the study of one particular candidate for white etching crack (WEC) initiation mechanism in wind turbine gearbox bearings: discharge current impulses flowing through bearing steel with associated thermal stresses and material fatigue. Using data/results from previously published works, the authors develop a series of models that are utilized to simulate these processes under various conditions/local microstructure configurations, as well as to verify the results of the previous numerical studies. Presented models show that the resulting stresses are several orders of magnitude below the fatigue limit/yield strength for the parameters used herein. Results and analysis of models …
Collective behaviours: from biochemical kinetics to electronic circuits
2013
In this work we aim to highlight a close analogy between cooperative behaviors in chemical kinetics and cybernetics; this is realized by using a common language for their description, that is mean-field statistical mechanics. First, we perform a one-to-one mapping between paradigmatic behaviors in chemical kinetics (i.e., non-cooperative, cooperative, ultra-sensitive, anti-cooperative) and in mean-field statistical mechanics (i.e., paramagnetic, high and low temperature ferromagnetic, anti-ferromagnetic). Interestingly, the statistical mechanics approach allows a unified, broad theory for all scenarios and, in particular, Michaelis-Menten, Hill and Adair equations are consistently recovered…
Shock-capturing schemes: high accuracy versus total-variation boundedness
2007
In this reseach work we analyze the total variation growth of some high order accurate reconstruction procedures used for the design of shock capturing schemes. This study allows to measure how oscillatory a high order accurate method is in terms of the basic elementary function chosen to increase the order of accuracy. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Correlations for estimating the specific capital cost of multi-effect distillation plants considering the main design trends and operating conditions
2018
Abstract This work proposes a correlation for the specific capital cost of multi-effect distillation (MED) plants, considering their main design options and parameters, such as the number of effects, size/capacity, and heat source temperature. These parameters are varied within a large range to cover as many different cases as possible. The cost correlation decouples the evaporator cost and includes in the expression the ratio of the heat exchanger area to a reference one. This area is calculated using a validated MED numerical model, with the results then processed to produce fitted expressions. Two versions of this correlation with different levels of complexity are proposed, which provid…
D2 and H2 adsorption capacity and selectivity in CHA zeolites: Effect of Si/Al ratio, cationic composition and temperature
2020
International audience; The work deals with the effect of composition of CHA zeolites on the adsorption and separation of H2 and D2 under cryogenic temperatures. In the first part of this work the effect of Si/Al ratio and cationic composition on single gas adsorption of H2 and D2 was studied at 77.4 K. It was found that the adsorption capacities increase with Al content up to Si/Al = 2.1. Unexpectedly, Na-CHA zeolite with the highest Al content (Si/Al = 1.1) adsorbs only negligible amount because of the collapse of the zeolite structure upon dehydration at 400°C. The Na-and Li-containing chabazites with Si/Al = 2.1 possess similar adsorption capacities. In contrast, progressive replacement…
Membrane Deformation and Its Effects on Flow and Mass Transfer in the Electromembrane Processes
2019
In the membrane processes, a trans-membrane pressure (TMP) may arise due to design features or operating conditions. In most applications, stacks for electrodialysis (ED) or reverse electrodialysis (RED) operate at low TMP (<
Analytic evaluation of Raman intensities in coupled-cluster theory
2007
We present the first implementation for the analytic calculation of polarizability derivatives using coupled-cluster theory. These derivatives are related to the intensity of bands seen in Raman spectroscopy, and are therefore important quantities that can also be measured experimentally. The required theory of analytic third derivatives is discussed and also connected to response theory to allow the calculation of frequency-dependent quantities. This work includes the use of a string-based general coupled-cluster/configuration-interaction program which makes the calculation of Raman intensities for arbitrary coupled-cluster or configuration-interaction methods up to the full configuration-…