Generalization of the fire line rotation model to curved fire lines

2006 ◽  
Vol 15 (4) ◽  
pp. 447 ◽  
Author(s):  
Imma Oliveras ◽  
Josep Piñol ◽  
Domingos X. Viegas
Keyword(s):  
Wind Field ◽  
Laboratory Experiments ◽  
Empirical Law ◽  
Fire Front ◽  
Line Elements ◽  
Straight Lines ◽  
Semi Empirical ◽  
Rotation Model

The concept of fire line rotation was applied to curved fire line elements like those of a point ignition fire in a slope or in a wind field. Convective effects induced by the fire modify the shape of the flame around its perimeter and affect the propagation of the fire front. From the analysis of laboratory experiments under wind or slope conditions, the existence of a rotation movement of the fire line elements is demonstrated. It is also shown that the semi-empirical law developed for straight lines is applicable with some adjustments to curved fire lines.

scholarly journals A Semi-empirical Law for Sputtering in Plasma Devices

1982 ◽  
Vol 35 (6) ◽  
pp. 699
Author(s):  
JL Cook ◽  
EK Rose ◽  
JW Connolly
Keyword(s):  
Helium Isotope ◽  
General Law ◽  
Empirical Law ◽  
Semi Empirical

A general law is given for sputtering coefficients as a function of the energy of hydrogen and helium isotope ions incident on metallic and graphite walls and limiters. The average over a Maxwellian spectrum is performed analytically.

The interpretation of laboratory experiments in the framework of an improved semi-empirical model

1994 ◽  
Vol 42 (12) ◽  
pp. 1031-1041 ◽  
Author(s):  
A. Verlicchi ◽  
A. La Spina ◽  
P. Paolicchi ◽  
A. Cellino
Keyword(s):  
Empirical Model ◽  
Laboratory Experiments ◽  
Semi Empirical

Transport of gas components across the soil – atmosphere interface influenced by wind conditions: A study with laboratory experiments and coupled subsurface – free flow modelling

2020 ◽  
Author(s):  
Lisa Bahlmann ◽  
Insa Neuweiler ◽  
Kathleen Smits ◽  
Katharina Heck ◽  
Edward Coltman ◽  
...  
Keyword(s):  
Porous Medium ◽  
Steady State ◽  
Wind Field ◽  
Concentration Distribution ◽  
Laboratory Experiments ◽  
Gas Injection ◽  
Soil Surface ◽  
Coupled Flow ◽  
Mass Fluxes ◽  
Gas Component

<p>Transport of gas components in the unsaturated zone and across the soil surface plays a role for transport of volatile contaminants, gases from pipe leaks or greenhouse gases. When estimating flow rates from the soil into the atmosphere, a good understanding of the transport processes is important. In general, component transport in the gas phase is considered to be mainly due to diffusion. However, the wind field above the soil surface can induce flow into the subsurface and influence transport and mass fluxes.</p><p>We present a study on gas component transport through dry and partially saturated soil into a free air flow above the soil surface, considering gas components of different density. Laboratory experiments in a quasi-2d sand tank were carried out. The tank was placed underneath a wind tunnel, and different wind velocities were used. Gases with different densities were injected with constant rate at an inlet port. Concentration distributions were measured continuously with sensors that were installed inside of the tank. After establishing a steady state concentration distribution, the gas injection was stopped and the decrease of gas concentrations inside the tank was monitored.</p><p>The experiments show that the concentration profiles under steady state gas injection depend on gas density and the different diffusion coefficients. They depend only slightly on the velocity of the overlaying wind field and the influence is mainly seen very close to the soil surface. The transient gas transport out of the soil, however, did not only depend on the different diffusion coefficients, but was clearly influenced by the wind field. The transient 2d concentration distribution fields illustrate that the wind field induced a flow field inside the tank that depends on the wind velocity and the component density and influences the gas component transport. The influence increases under partly saturated conditions.</p><p>To reproduce the transport correctly, it is necessary to capture the coupling between free flow and porous medium flow and the transport in the coupled flow. To do so, we use a fully coupled flow and transport model implemented into the environment DuMu<sup>x</sup> ((Dune for Multi-(Phase,Component, Scale, ...) flow and transport in porous media). It can be shown that including the coupling concept, the main features of the concentration distributions can be reproduced for both the steady state and the transient case. With the model it is also demonstrated, that although advective fluxes inside the porous medium introduced by the wind field (horizontal and lateral) are relatively small in comparison to the diffusive fluxes, they cause relevant changes in the concentration distribution and thus indirectly influence the mass fluxes inside the porous medium and across the soil-atmosphere interface.</p>

Semi-empirical law for fatigue resistance of redistribution layers in chip-scale packages

2021 ◽  
Vol 120 ◽  
pp. 114096
Author(s):  
M. van Soestbergen ◽  
Q. Jiang ◽  
J.J.M. Zaal ◽  
R. Roucou ◽  
A. Dasgupta
Keyword(s):  
Fatigue Resistance ◽  
Empirical Law ◽  
Semi Empirical

Covering of cometary nucleus by refractory crust and its evolution into asteroid-like body

1999 ◽  
Vol 173 ◽  
pp. 365-370
Author(s):  
Kh.I. Ibadinov
Keyword(s):  
Laboratory Experiments ◽  
Cometary Nucleus ◽  
Sublimation Rate ◽  
Cometary Nuclei ◽  
Short Period Comet ◽  
Short Period ◽  
Brightness Decrease ◽  
Crust Thickness ◽  
Ice Sublimation ◽  
Period Comet

AbstractFrom the established dependence of the brightness decrease of a short-period comet dependence on the perihelion distance of its orbit it follows that part of the surface of these cometary nuclei gradually covers by a refractory crust. The results of cometary nucleus simulation show that at constant insolation energy the crust thickness is proportional to the square root of the insolation time and the ice sublimation rate is inversely proportional to the crust thickness. From laboratory experiments resulted the thermal regime, the gas productivity of the nucleus, covering of the nucleus by the crust, and the tempo of evolution of a short-period comet into the asteroid-like body studied.

Domain Formation in Synthetic Quartz

1971 ◽  
Vol 29 ◽  
pp. 156-157
Author(s):  
Joseph J. Comer
Keyword(s):  
Electron Beam ◽  
Room Temperature ◽  
Domain Formation ◽  
Synthetic Quartz ◽  
Transmission Electron ◽  
Black Spots ◽  
Diffraction Mode ◽  
Domain Boundaries ◽  
Kikuchi Lines ◽  
Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

When Does Voice Have to be More Than Only Listening? Procedural Justice Effects as a Function of Confident Leadership

2010 ◽  
Vol 9 (2) ◽  
pp. 69-78 ◽  
Author(s):  
David De Cremer ◽  
Maarten Wubben
Keyword(s):  
Procedural Justice ◽  
Interaction Effect ◽  
Laboratory Experiments ◽  
Negative Emotions

The present research examined how voice procedures and leader confidence affect participants’ negative emotions and willingness to withdraw. It was predicted that receiving voice would be valued out of instrumental concerns, but only when the enacting leader was high in confidence. Two laboratory experiments indeed showed an interaction between type of voice (pre-decisional vs. post-decisional) and leader’s confidence (low vs. high) on participants’ negative emotions and willingness to withdraw. In particular, post-decision voice only led to more negative responses than did pre-decision voice when the enacting leader was high in confidence. Negative emotions mediated this interaction effect of type of voice on willingness to withdraw. Implications for integrating the leadership and procedural justice literatures are discussed.

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