scholarly journals PHOTOCHEMISTRY OF VISUAL PURPLE

1921 ◽  
Vol 3 (3) ◽  
pp. 285-290 ◽  
Author(s):  
Selig Hecht
Keyword(s):  
Diffusion Process ◽  
Temperature Coefficient ◽  
Chemical Process

The temperature coefficient of the bleaching of visual purple by light is 1.00 over a range of 30 degrees. This indicates that the monomolecular course of the reaction represents a real chemical process, as opposed to a possible diffusion process, and that the reaction is probably simple in nature.

Nature of the Diffusion Process in Rubber

1937 ◽  
Vol 10 (4) ◽  
pp. 673-674 ◽  
Author(s):  
Richard M. Barrer
Keyword(s):  
Diffusion Process ◽  
Temperature Coefficient ◽  
Gas Diffusion ◽  
Diffusion System ◽  
Large Temperature ◽  
Molecular Weights ◽  
Diffusion Systems ◽  
Diffusion Of Gases

Abstract It is known that silica-gas diffusion systems exemplify a type of non-specific activated diffusion process, as opposed to the specific type of diffusion system, such as hydrogen-palladium. It seemed that the diffusion of gases through other “glass-like” materials such as some organic membranes, for example rubber, might offer further examples of non-specific activated diffusion. The data needed to test this hypothesis were available in papers by Edwards and Pickering, and by Dewar. Graham first noted the large temperature coefficient of the diffusion process through rubber, and that the diffusion velocities had no connection with the molecular weights.

scholarly journals THE INFLUENCE OF LIGHT, TEMPERATURE, AND OTHER CONDITIONS ON THE ABILITY OF NITELLA CELLS TO CONCENTRATE HALOGENS IN THE CELL SAP

1926 ◽  
Vol 10 (1) ◽  
pp. 121-146 ◽  
Author(s):  
D. R. Hoagland ◽  
P. L. Hibbard ◽  
A. R. Davis
Keyword(s):  
Temperature Coefficient ◽  
Chemical Process ◽  
External Solution ◽  
Light Energy ◽  
Dilute Solution ◽  
Reciprocal Relations ◽  
Analytical Technique

1. By the use of a special analytical technique it has been possible to study the accumulation of halogens in the cell sap of Nitella. 2. From a dilute solution, Br may be accumulated in the sap in a concentration much greater than that of the external solution. The conductivity of the sap may be markedly increased by such accumulation. The process is a slow one so that a month or more may be required to approach equilibrium. 3. Cl may be lost from the cell as a result of the accumulation of Br and vice versa. Other reciprocal relations between Cl and Br are indicated. 4. At equilibrium practically as much Br accumulated in the sap with an external solution containing 1 milli-equivalent of Br as with one containing 5 milli-equivalents. 5. Light energy was indispensable to the accumulation of Br. The temperature coefficient was characteristic of a chemical process.

The thermo-osmosis of gases through a membrane I. Theoretical

1952 ◽  
Vol 210 (1102) ◽  
pp. 377-387 ◽  
Keyword(s):  
Temperature Gradient ◽  
Diffusion Process ◽  
Temperature Coefficient ◽  
Thermal Diffusion ◽  
Stationary State ◽  
Pressure Ratio ◽  
Irreversible Processes ◽  
Heat Of Solution ◽  
Heat Of Transport ◽  
Thermal Diffusion Process

The process of thermo-osmosis is the passage of a fluid through a membrane due to a temperature gradient. Under suitable conditions it gives rise to a stationary difference of pressure. The thermo-osmosis of a gas through a membrane in which it is slightly soluble is due partly to the temperature coefficient of its solubility and partly to the existence of a thermal diffusion process inside the membrane. A theory is developed on the basis of Onsager’s treatment of irreversible processes and leads to equations giving the rate of permeation and the pressure ratio at the stationary state. The magnitude of the effect depends on the algebraic sum of the heat of solution and the heat of transport within the membrane.

Burgers fluid flow in perspective of Buongiorno’s model with improved heat and mass flux theory for stretching cylinder

2020 ◽  
Vol 92 (3) ◽  
pp. 31101
Author(s):  
Zahoor Iqbal ◽  
Masood Khan ◽  
Awais Ahmed
Keyword(s):  
Diffusion Process ◽  
Mathematical Formulation ◽  
Thermal Relaxation ◽  
Mass Diffusion ◽  
Stretching Cylinder ◽  
Discussion Section ◽  
Buongiorno’S Model ◽  
Homotopy Analysis ◽  
Burgers Fluid ◽  
Diffusion Phenomena

In this study, an effort is made to model the thermal conduction and mass diffusion phenomena in perspective of Buongiorno’s model and Cattaneo-Christov theory for 2D flow of magnetized Burgers nanofluid due to stretching cylinder. Moreover, the impacts of Joule heating and heat source are also included to investigate the heat flow mechanism. Additionally, mass diffusion process in flow of nanofluid is examined by employing the influence of chemical reaction. Mathematical modelling of momentum, heat and mass diffusion equations is carried out in mathematical formulation section of the manuscript. Homotopy analysis method (HAM) in Wolfram Mathematica is utilized to analyze the effects of physical dimensionless constants on flow, temperature and solutal distributions of Burgers nanofluid. Graphical results are depicted and physically justified in results and discussion section. At the end of the manuscript the section of closing remarks is also included to highlight the main findings of this study. It is revealed that an escalation in thermal relaxation time constant leads to ascend the temperature curves of nanofluid. Additionally, depreciation is assessed in mass diffusion process due to escalating amount of thermophoretic force constant.

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