scholarly journals Time evolution of the Luttinger model with nonuniform temperature profile

2017 ◽  
Vol 95 (23) ◽  
Author(s):  
Edwin Langmann ◽  
Joel L. Lebowitz ◽  
Vieri Mastropietro ◽  
Per Moosavi
Keyword(s):  
Temperature Profile ◽  
Time Evolution ◽  
Nonuniform Temperature ◽  
Luttinger Model

Fast scanning heterodyne receiver for the measurement of the time evolution of the electron temperature profile on the Tokamak Fusion Test Reactor

1984 ◽  
Vol 55 (11) ◽  
pp. 1739-1743 ◽  
Author(s):  
G. Taylor ◽  
P. Efthimion ◽  
M. McCarthy ◽  
V. Arunasalam ◽  
R. Bitzer ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Temperature Profile ◽  
Time Evolution ◽  
Heterodyne Receiver ◽  
Test Reactor

Stabilization of Filament Production Rate for Screw Extrusion-Based Polymer Three-Dimensional-Printing

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Shumon Koga ◽  
David Straub ◽  
Mamadou Diagne ◽  
Miroslav Krstic
Keyword(s):  
Differential Equation ◽  
3D Printing ◽  
Temperature Profile ◽  
Time Evolution ◽  
Output Feedback ◽  
Three Dimensional ◽  
Output Feedback Control ◽  
Raw Material ◽  
Interface Position ◽  
Screw Extrusion

Abstract Polymer three-dimensional (3D)-printing has been commercialized rapidly during recent years; however, there remains a matter of improving the manufacturing speed. Screw extrusion has a strong potential to fasten the process through the simultaneous operation of the filament production and the deposition. This paper develops a control algorithm for screw extrusion-based 3D printing of thermoplastic materials through an observer-based output feedback design. We consider the thermodynamic model describing the time evolution of the temperature profile of an extruded polymer by means of a partial differential equation (PDE) defined on the time-varying domain. The time evolution of the spatial domain is governed by an ordinary differential equation that reflects the dynamics of the position of the phase change interface between polymer granules and molten polymer deposited as a molten filament. The steady-state profile of the distributed temperature along the extruder is obtained when the desired setpoint for the interface position is prescribed. To enhance the feasibility of our previous design, we develop a PDE observer to estimate the temperature profile via measured values of surface temperature and the interface position. An output feedback control law considering a cooling mechanism at the boundary inlet as an actuator is proposed. In extruders, the control of raw material temperature is commonly achieved using preconditioners as part of the inlet feeding mechanism. For some given screw speeds that correspond to slow and fast operating modes, numerical simulations are conducted to prove the performance of the proposed controller. The convergence of the interface position to the desired setpoint is achieved under physically reasonable temperature profiles.

scholarly journals Fast scanning heterodyne receiver for the measurement of the time evolution of the electron temperature profile on TFTR

1984 ◽  
Author(s):  
G. Taylor ◽  
P. Efthimion ◽  
M. McCarthy ◽  
V. Arunasalam ◽  
R. Bitzer ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Temperature Profile ◽  
Time Evolution ◽  
Heterodyne Receiver

Comparison of Large Eddy Simulation and Unsteady Reynolds-Averaged Navier–Stokes for Evaluation of Entropy Noise

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Eduard Ron ◽  
Kam Chana
Keyword(s):  
Large Eddy Simulation ◽  
Temperature Profile ◽  
Numerical Procedure ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Nonuniform Temperature ◽  
Temperature Variations ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Reynolds Averaged Navier Stokes

This paper expands on the numerical simulation of entropy noise by performing a comparison of two commonly used models for resolving turbulent flow field: large eddy simulation (LES) and unsteady Reynolds-averaged Navier–Stokes (URANS). A brand new numerical procedure was developed allowing an accurate reproduction of two-dimensional spatial and temporal temperature variations of a nonuniform temperature profile. Experimental investigation was performed for the same nonuniform temperature profile, and comparison of the entropy noise level measured experimentally and evaluated numerically using the two models was performed. It was shown that large eddy simulation allows a better prediction of entropy noise within the developed numerical procedure than URANS.

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