scholarly journals Numerical prediction of steady state temperature based on transient measurements

2018 ◽  
Vol 240 ◽  
pp. 05024
Author(s):  
Ewa Pelińska-Olko ◽  
Marek Lewkowicz
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Heat Exchange ◽  
Time Range ◽  
Radiative Heat Exchange ◽  
Steady State Temperature ◽  
Long Time ◽  
Experimental Values ◽  
Short Time ◽  
Transient Measurements

We show how to use numerical analysis of short-time range experimental data for predicting the limit steady-state value of the investigated parameter. In this article the approach has been applied to a specific, although typical, thermal problem: determining the average steady-state temperature of a heater in the convective and radiative heat exchange with the environment. First, we describe a heat exchange experiment aimed at obtaining temperature experimental data in both short and long time range. Then we present a methodology for applying two methods, i.e., neural networks and least squares approximations, for obtaining predictions about the steady-state temperature values based on short time experimental data. The aim of the study is to compare the predictions to each other and to the long time experimental values, with the aim of determining the applicability range of the two methods.

Turn-on and Charge Build-up Dynamics in Polymer Field Effect Transistors

2005 ◽  
Vol 871 ◽  
Author(s):  
Yohai Roichman ◽  
Nir Tessler
Keyword(s):  
Power Law ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Time Range ◽  
Gate Bias ◽  
Current Dependence ◽  
Turn On ◽  
Long Time ◽  
Source Current ◽  
Short Time

AbstractTurn-on dynamics of polymer field effect transistors were examined experimentally over a wide timescale. We found that the source current dependence on time following switch on of the gate bias exhibits a power law at the short time range, and an exponential decay at the intermediate to long time range. We demonstrate that the transistor dynamic behavior is governed by the channel charge build-up, and can be described accurately by a simple capacitor-resistor distributed line model.

scholarly journals Using An Exponential Equation to Describe Adsorption/Desorption Processes of Water on Composite Soil at Constant Pressure

2003 ◽  
Vol 21 (4) ◽  
pp. 383-388
Author(s):  
Lianxi Ma ◽  
James C. Holste ◽  
Kenneth R. Hall
Keyword(s):  
Experimental Data ◽  
Water Vapour ◽  
Constant Pressure ◽  
Exponential Equation ◽  
Desorption Process ◽  
Experimental Time ◽  
Long Time ◽  
Experimental Values ◽  
Adsorption Desorption

Using the assumption that adsorption as a function of time may be expressed by an exponential equation, viz. ΔM = g + he−t/τ, it is possible to obtain the amount of water vapour adsorbed by a composite soil without waiting for equilibrium, which usually takes a long time. Given the experimental data for the amounts adsorbed versus time, one can determine g, h and τ, together with the amounts adsorbed at equilibrium by extrapolating the above equation to t → ∞. It is also possible to calculate the error trends in these parameters as a function of time by comparing the values at time t with those obtained for the longest experimental time. The error trends of the equation with time arise from the comparison of the experimental values with those predicted by the exponential equation. We have discovered that although different lengths of time are necessary for different pressures, generally a time between 1.5τ and 2τ is sufficient to obtain reliable results with errors less than 5%. We have also found that this equation describes the desorption process as well.

Over-Temperature Forecasts on Electronic Packages Through a Transient R–C Model

1999 ◽  
Vol 122 (1) ◽  
pp. 42-47
Author(s):  
Ben-Je Lwo ◽  
Kun-Fu Tseng ◽  
Ching-Hsing Kao ◽  
Luke Su Lu
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Real Time ◽  
Electronic Packaging ◽  
Input Power ◽  
Electronic Packages ◽  
Temperature Prediction ◽  
Steady State Temperature ◽  
New Methodologies ◽  
Capacitance Model

Based on experimental data, a simple R–C (thermal resistance–heat capacitance) model with software precaution strategies are proposed in this paper to predict the steady-state temperature of the circuit in an electronic packaging in real time. Further developments on the new methodology lead to real time monitoring if input power and/or the environment are changing during operations. It is concluded that the new methodologies, which make the over-temperature prediction much more reliable, efficient, sensible, and faster, can be easily employed for over-temperature protection designs on electronic packaging. [S1043-7398(00)00301-7]

Flows at Moderate Reynolds Numbers

2018 ◽  
Author(s):  
Sauro Succi
Keyword(s):  
Steady State ◽  
Reynolds Numbers ◽  
Complex Geometries ◽  
Computational Power ◽  
Flow Configuration ◽  
Major Interest ◽  
Long Time ◽  
Pulsatile Flows ◽  
Short Time ◽  
Very High

This chapter presents the application of LBE to flows at moderate Reynolds numbers, typically hundreds to thousands. This is an important area of theoretical and applied fluid mechanics, one that relates, for instance, to the onset of nonlinear instabilities and their effects on the transport properties of the unsteady flow configuration. The regime of Reynolds numbers at which these instabilities take place is usually not very high, of the order of thousands, hence basically within reach of present day computer capabilities. Nonetheless, following the full evolution of these transitional flows requires very long-time integrations with short time-steps, which command substantial computational power. Therefore, efficient numerical methods are in great demand. Also of major interest are steady-state or pulsatile flows at moderate Reynolds numbers in complex geometries, such as they occur, for instance, in hemodynamic applications. The application of LBE to such flows will also briefly be mentioned

scholarly journals Sliding of spherical ball on solid lubricating coating combined with wear process

2021 ◽  
Vol 93 (1) ◽  
pp. 39-50
Author(s):  
Marcin Białas ◽  
Jan Maciejewski ◽  
Stanisław Kucharski
Keyword(s):  
Steady State ◽  
Time Scale ◽  
Contact Region ◽  
Short Time Scale ◽  
Steady State Condition ◽  
Wear Process ◽  
Spherical Ball ◽  
Long Time ◽  
Short Time ◽  
Solid Lubricating Coating

In present paper we show results of ball-on-disk wear experiment of MoS2 film deposited on Ti6Al4V substrate. The ball materials is aluminum oxide. The tests are performed for different surrounding temperature conditions: 20 oC, 200 oC and 350 oC. It is shown that depth of the wear groove increases with increasing surrounding temperature. A finite element modeling approach is next developed to mimic the experimental observations of ball-on-disk wear process. It is based on the assumption of steady state condition developed during short time scale at contact region. The steady state results can next be applied to long time scale in which wear process is numerically simulated. Model results are compared with experimentally obtained wear groove and show satisfactory agreement.

scholarly journals Quantitative analysis of non-equilibrium systems from short-time experimental data

2021 ◽  
Author(s):  
Sreekanth K Manikandan ◽  
Subhrokoli Ghosh ◽  
Avijit Kundu ◽  
Biswajit Das ◽  
Vipin Agrawal ◽  
...  
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Quantitative Analysis ◽  
Large Class ◽  
Colloidal Particle ◽  
Particle System ◽  
Thermodynamic Force ◽  
Trajectory Data ◽  
Short Time ◽  
Non Equilibrium

Abstract We provide a minimal strategy for the quantitative analysis of a large class of non-equilibrium systems in a steady state using the short-time Thermodynamic Uncertainty Relation (TUR). From short-time trajectory data obtained from experiments, we demonstrate how we can simultaneously infer quantitatively, both the thermodynamic force field acting on the system, as well as the exact rate of entropy production. We benchmark this scheme first for an experimental study of a colloidal particle system where exact analytical results are known, before applying it to the case of a colloidal particle in a hydrodynamical flow field, where neither analytical nor numerical results are available. Our scheme hence provides a means, potentially exact for a large class of systems, to get a quantitative estimate of the entropy produced in maintaining a non-equilibrium system in a steady state, directly from experimental data.

Light-Induced, Short-Time Annealing of Silicon-Implanted Layers

1984 ◽  
Vol 35 ◽  
Author(s):  
D. Wouters ◽  
H.E. Maes
Keyword(s):  
Steady State ◽  
Annealing Process ◽  
Electrical Activation ◽  
Illumination Time ◽  
Steady State Temperature ◽  
Transient Period ◽  
Short Time ◽  
Constant Maximum ◽  
System Operating ◽  
Diffusion Redistribution

ABSTRACTShort time anneal experiments were performed in a specially developed annealing system based on a bank of Tungsten-Halogen lamps. The annealing process during the temperature transient was studied as a function of the illumination time with the system operating in the constant maximum power regime. By using this procedure it was shown that electrical activation of all elements (B, P, As) considered in this study is completed within the transient period without noticeable diffusion. Redistribution of the implanted profiles was only observed for longer times after the steady state temperature was reached. Pre-amorphization with Argon is found to significantly alter and retard the annealing behaviour.

scholarly journals Synthesis of Curcumin Derivative Assisted by Microwave Irradiation

2019 ◽  
Vol 16 (2) ◽  
pp. 153
Author(s):  
Sabtanti Harimurti ◽  
Winny Setyonugroho ◽  
Ardi Pramono ◽  
Rizky Hidayaturahmah
Keyword(s):  
Experimental Data ◽  
Microwave Irradiation ◽  
Synthesis Method ◽  
Conventional Heating ◽  
Cancer Drug ◽  
Efficient Synthesis ◽  
Cancer Drug Discovery ◽  
Long Time ◽  
Short Time ◽  
Curcumin Derivative

Synthesis of curcumin derivate is commonly conducted using conventional heating like heating mantel. The synthesis was usually done in the very long time. An experiment on finding an efficient synthesis method may be necessary to conduct, such as using microwave to replace the energy source. The synthesis of curcumin derivate 1,5-bis(4’-hydroxy-3’-metoxyphenyl)-1,4-pentadiene-3-one or gamavuton-0 assisted by microwave irradiation has been carried out. This synthesis was done on propose of cancer drug discovery to answer the search of new cancer drug on the increase of cancer incidence recently. The synthesis was done under microwave irradiation using vanillin and acetone as the starting material, and hydrochloric acid as the catalyst. Based on the experimental data, the microwave irradiation significantly reduces the reaction time. By using microwave irradiation, the synthesis can be done in a short time.

Inverse problem with finite overdetermination for steady-state equations of radiative heat exchange

2018 ◽  
Vol 460 (2) ◽  
pp. 737-744 ◽  
Author(s):  
Alexander Yu. Chebotarev ◽  
Gleb V. Grenkin ◽  
Andrey E. Kovtanyuk ◽  
Nikolai D. Botkin ◽  
Karl-Heinz Hoffmann
Keyword(s):  
Inverse Problem ◽  
Steady State ◽  
Heat Exchange ◽  
Radiative Heat ◽  
Radiative Heat Exchange ◽  
State Equations

Thermal-Mechanical Modelling of the Rolling-Plus-Sliding With Frictional Heating of a Locomotive Wheel

1995 ◽  
Vol 117 (3) ◽  
pp. 418-422 ◽  
Author(s):  
V. Gupta ◽  
G. T. Hahn ◽  
P. C. Bastias ◽  
C. A. Rubin
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Frictional Heating ◽  
Finite Element Models ◽  
Steady State Temperature ◽  
Mechanical Modelling ◽  
Computing Effort ◽  
Long Time ◽  
D Model ◽  
Locomotive Wheels

This paper examines finite element models for studying the long time frictional heating of locomotive wheels. The aim is to obtain the temperature distribution and the thermal and residual stresses in the wheel, for given conditions of rolling-plus-sliding, with the least computing effort. Initially a rigorous 3-D model is employed. Then this model is reduced to a much simpler but equivalent 2-D axisymmetric model with reasonable assumptions. It is shown, with the help of the 3-D model, that the actual temperature distribution is fluctuating and exhibits a sharp spike during each wheel rotation. For a part of the cycle the temperature is much higher than the steady state temperature calculated from the 2-D model.

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