scholarly journals Taste of time: A porous-medium model for human tongue surface with implications for early taste perception

2019 ◽  
Author(s):  
Zhenxing Wu ◽  
Kai Zhao
Keyword(s):  
Porous Medium ◽  
Diffusion Processes ◽  
Molecular Size ◽  
Transport Processes ◽  
Taste Perception ◽  
Taste Intensity ◽  
Human Tongue ◽  
Tongue Surface ◽  
Transport And Diffusion ◽  
And Diffusion

AbstractMost sensory systems are remarkable in their temporal precision, reflected in such phrases as “a flash of light” or “a twig snap”. Yet, the temporal response of human taste perception is complicated by the transport and diffusion processes of the stimuli through the papillae, saliva, taste pore, etc., to reach the taste receptors, processes that are poorly understood. In this study, we addressed this knowledge gap by modeling the transport and diffusion processes within the tongue surface through a novel micro-fiber porous medium approach and found that time-concentration profiles within the papilla zone rises with significant delay that well match experimental ratings of perceived taste intensity for both rapid stimuli pulses and longer sip-and-hold exposures. Diffusivity of taste stimuli, determined mostly by molecular size, correlates greatly with time and slope to reach peak intensity: smaller molecular size may lead to quicker taste perception. Our study demonstrates the novelty of modeling the human tongue as a porous material to drastically simplify computational approaches and that peripheral transport processes may significantly affect the temporal profile of taste perception.

Effect of Channelling in a Porous Medium on Radionuclide Migration

1982 ◽  
Vol 15 ◽  
Author(s):  
Asit K. Ray ◽  
Shyam Nair
Keyword(s):  
Porous Medium ◽  
Anisotropic Diffusion ◽  
Diffusion Processes ◽  
Convective Diffusion ◽  
Unsteady State ◽  
Rock Matrix ◽  
Radionuclide Migration ◽  
Discharge Rates ◽  
Channel Thickness ◽  
And Diffusion

ABSTRACTA mathematical model has been developed to study the effect of channelling in a porous medium surrounding a repository on the migration of radionuclides. The porous medium is treated as an infinite medium containing parallel, unconnected channels; each channel is surrounded by a rock matrix. The migration in the channel is controlled by convection and diffusion processes in the direction of the flow, whereas in the rock matrix it is dominated by anisotropic diffusion in the longitudinal and transverse directions. Unsteady state convective-diffusion equations for this system have been solved. At the channel-rock matrix interface the concentration and flux were watched to obtain concentration profiles and discharge rates at downstream locations. By means of a parametric study the effects of channel thickness, diffusion coefficients, and flow velocity on the migration rate are elucidated.

Transport and diffusion processes in trehalose–water solutions: Theory and experiments

2006 ◽  
Vol 330 (1-2) ◽  
pp. 90-100 ◽  
Author(s):  
S. Magazù ◽  
G. Maisano ◽  
F. Migliardo ◽  
N.P. Malomuzh ◽  
E.V. Orlov
Keyword(s):  
Diffusion Processes ◽  
Water Solutions ◽  
Transport And Diffusion ◽  
And Diffusion ◽  
Theory And Experiments

scholarly journals Water renewal timescales in an ecological reconstructed lagoon in China

2013 ◽  
Vol 15 (3) ◽  
pp. 991-1001 ◽  
Author(s):  
Xueping Gao ◽  
Yuanyuan Chen ◽  
Chen Zhang
Keyword(s):  
Exposure Time ◽  
Diffusion Processes ◽  
Three Dimensional ◽  
Pollution Source ◽  
Tidal Inlet ◽  
Wind Condition ◽  
Water Renewal ◽  
Transport And Diffusion ◽  
Ecological Reconstruction ◽  
And Diffusion

To improve water quality and construct a landscape lagoon in China, an ecological reconstruction plan for the Qilihai Lagoon (Changli County, Hebei) is proposed. A three-dimensional numerical model (EFDC) was used to study the water renewal capacity in the reconstructed lagoon by using residence time, exposure time and connectivity as timescales. The influences of wind and the depth of the tidal inlet of the lagoon on water renewal capacity were also investigated. The results show that the transport and diffusion processes in the lagoon were strongly influenced by wind and the modification of the tidal inlet. The lagoon under a no wind condition exhibited a low water renewal capacity, especially at the end areas (exposure time, 700–1,000 days). The wind action notably enhanced the water renewal capacity in the lagoon, and the exposure times were all lower than 400 days in the whole region. The optimal inlet depth for the water renewal in the lagoon was predicted to be 4.0 m. The connectivity matrices identified which areas of the domain would be most affected by a pollution source under different conditions. This study examines transport and diffusion processes in a reconstructed lagoon, which could be informative for ecological reconstruction planning.

Meridional Circulation, Turbulence, and Diffusion Processes in Stars

1976 ◽  
Vol 32 ◽  
pp. 109-116 ◽  
Author(s):  
S. Vauclair
Keyword(s):  
Convection Zone ◽  
Diffusion Processes ◽  
Meridional Circulation ◽  
Diffusion Time ◽  
Work In Progress ◽  
First Results ◽  
Stellar Envelopes ◽  
And Diffusion ◽  
Turbulence And Diffusion ◽  
Hr Diagram

This paper gives the first results of a work in progress, in collaboration with G. Michaud and G. Vauclair. It is a first attempt to compute the effects of meridional circulation and turbulence on diffusion processes in stellar envelopes. Computations have been made for a 2 Mʘstar, which lies in the Am - δ Scuti region of the HR diagram.Let us recall that in Am stars diffusion cannot occur between the two outer convection zones, contrary to what was assumed by Watson (1970, 1971) and Smith (1971), since they are linked by overshooting (Latour, 1972; Toomre et al., 1975). But diffusion may occur at the bottom of the second convection zone. According to Vauclair et al. (1974), the second convection zone, due to He II ionization, disappears after a time equal to the helium diffusion time, and then diffusion may happen at the bottom of the first convection zone, so that the arguments by Watson and Smith are preserved.

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