Visualization of Global Flow Structures Using Multiple Levels of Topology

1999 ◽  
pp. 45-52 ◽  
Author(s):  
Wim de Leeuw ◽  
Robert van Liere
Keyword(s):  
Flow Structures ◽  
Global Flow ◽  
Multiple Levels

Mean flow structure in horizontal convection

2017 ◽  
Vol 812 ◽  
pp. 525-540 ◽  
Author(s):  
Olga Shishkina
Keyword(s):  
Aspect Ratio ◽  
Heat Supply ◽  
Fluid Layer ◽  
Flow Structures ◽  
Convection Cell ◽  
Spatial Distributions ◽  
Global Flow ◽  
Mean Flow ◽  
Horizontal Convection ◽  
The Mean

We analyse the global flow structures in horizontal convection systems, where the heat supply and removal takes place through separated parts of a lower horizontal surface of a fluid layer. The results are based on direct numerical simulations for the length-to-height aspect ratio of the convection cell $\unicode[STIX]{x1D6E4}=10$, Rayleigh number $\mathit{Ra}$ from $3\times 10^{8}$ to $3\times 10^{11}$ and Prandtl number $\mathit{Pr}$ from 0.05 to 50. The structure of the mean flows in horizontal convection is described in terms of time-averaged spatial distributions of the temperature, velocity, kinetic energy, thermal and kinetic dissipation rates. A possible scenario of transition to turbulent horizontal convection in the whole convection cell of a large aspect ratio is discussed.

Thermodynamic Formulation of the Constructal Law

2003 ◽  
Author(s):  
A. Bejan ◽  
S. Lorente
Keyword(s):  
Flow Resistance ◽  
Flow System ◽  
Global Constraints ◽  
Flow Structures ◽  
Nonequilibrium Flow ◽  
Global Flow ◽  
Constructal Law ◽  
Equilibrium Structures ◽  
Heat And Fluid Flow ◽  
Dimensional Domain

In this paper we develop an analytical and graphical formulation of the constructal law of maximization of flow access in systems with heat and fluid flow irreversibilities and freedom to change configuration. The flow system has global objective (e.g., minimization of global flow resistance) and global constraints (e.g., overall size, and total duct volume). The infinity of possible flow structures occupies a region of the two-dimensional domain of “global performance versus freedom to morph.” This region of “nonequilibrium” flow structures is bounded by a line representing the best flow structures that are possible when the freedom to morph is limited. The best of all such structures are the “equilibrium” structures: here the performance level is the highest, and it does not change even though the flow architecture continues to change with maximum freedom. The universality of this graphical and analytical presentation is illustrated with examples of flow structures from three classes: flow between two points, flow between a circle and its center, and flow between one point and an area. In sum, this paper presents an analytical and graphical formulation of the constructal principle of thermodynamic optimization of flow architecture under global constraints. The place of this new and self-standing principle in the greater framework of thermodynamics is outlined.

Particle characterization of CVD tungsten metallization for 64 MBIT DRAM

1991 ◽  
Vol 49 ◽  
pp. 896-897
Author(s):  
Marylyn Bennett-Lilley ◽  
Thomas T.H. Fu ◽  
David D. Yin ◽  
R. Allen Bowling
Keyword(s):  
Chemical Vapor ◽  
Device Performance ◽  
Particle Characterization ◽  
Particle Generation ◽  
Tungsten Hexafluoride ◽  
Homogeneous Particle ◽  
Multiple Levels ◽  
Circuit Density ◽  
Sources Of Contamination

Chemical Vapor Deposition (CVD) tungsten metallization is used to increase VLSI device performance due to its low resistivity, and improved reliability over other metallization schemes. Because of its conformal nature as a blanket film, CVD-W has been adapted to multiple levels of metal which increases circuit density. It has been used to fabricate 16 MBIT DRAM technology in a manufacturing environment, and is the metallization for 64 MBIT DRAM technology currently under development. In this work, we investigate some sources of contamination. One possible source of contamination is impurities in the feed tungsten hexafluoride (WF6) gas. Another is particle generation from the various reactor components. Another generation source is homogeneous particle generation of particles from the WF6 gas itself. The purpose of this work is to investigate and analyze CVD-W process-generated particles, and establish a particle characterization methodology.

Survey Actioning: Driving Positive Change at Multiple Levels

2011 ◽  
Author(s):  
Carly S. Bruck ◽  
Rita Williams ◽  
Tripp Welch ◽  
Phil Warden ◽  
Patrick K. Hyland
Keyword(s):  
Positive Change ◽  
Multiple Levels

Evaluating the etiology of climate: Building understanding from multiple levels

2003 ◽  
Author(s):  
Chera L. Haworth ◽  
Andrea F. Snell ◽  
Daniel J. Svyantek ◽  
Gary A. Kustis
Keyword(s):  
Multiple Levels

Learning at Multiple Levels of Abstraction: The Case of Verb Argument Constructions

2007 ◽  
Author(s):  
Amy Perfors ◽  
Charles Kemp ◽  
Elizabeth Wonnacott ◽  
Joshua B. Tenenbaum
Keyword(s):  
Levels Of Abstraction ◽  
Multiple Levels

Multiple Levels of Crowding

2014 ◽  
Author(s):  
Ruth Kimchi ◽  
Yossef Pirkner
Keyword(s):  
Multiple Levels

Review of Flap Monitoring Technology in 2020

2020 ◽  
Vol 36 (06) ◽  
pp. 722-726
Author(s):  
Adam Jacobson ◽  
Oriana Cohen
Keyword(s):  
Head And Neck ◽  
Free Flap ◽  
Loss Rate ◽  
Early Recognition ◽  
Postoperative Patient ◽  
Free Flap Monitoring ◽  
Improved Outcomes ◽  
Vascular Compromise ◽  
Flap Monitoring ◽  
Multiple Levels

AbstractAdvances in free flap reconstruction of complex head and neck defects have allowed for improved outcomes in the management of head and neck cancer. Technical refinements have decreased flap loss rate to less than 4%. However, the potential for flap failure exists at multiple levels, ranging from flap harvest and inset to pedicle lay and postoperative patient and positioning factors. While conventional methods of free flap monitoring (reliant on physical examination) remain the most frequently used, additional adjunctive methods have been developed. Herein we describe the various modalities of both invasive and noninvasive free flap monitoring available to date. Still, further prospective studies are needed to compare the various invasive and noninvasive technologies and to propel innovations to support the early recognition of vascular compromise with the goal of even greater rates of flap salvage.

Sign in / Sign up

Export Citation Format

Share Document