A LOW TEMPERATURE PARTICLE SIZE EFFECT ON THE HEAT CAPACITY OF SODIUM CHLORIDE

1955 ◽  
Vol 33 (2) ◽  
pp. 240-244 ◽  
Author(s):  
D. Patterson ◽  
J. A. Morrison ◽  
F. W. Thompson
Keyword(s):  
Particle Size ◽  
Heat Capacity ◽  
Sodium Chloride ◽  
Low Temperature ◽  
Size Effect ◽  
Specific Heat ◽  
Significant Contribution ◽  
Particle Size Effect ◽  
Extensive Property ◽  
Effect Of Particle Size

An effect of particle size upon the heat capacity of sodium chloride has been found in the temperature range 9° to 21°K. The experiments were done with three NaCl samples of specific surfaces between 38 and 59 sq. meters per gm. The observed effect has the temperature dependence predicted by theory but its magnitude is three to four times larger than expected. It is unlikely that adsorbed gases have made any significant contribution in the experiments. The accuracy with which the specific heat and surface area differences have been determined is not high enough to show definitely whether or not the surface specific heat is an extensive property of the surface.

FREQUENCY SPECTRA OF FREE LATTICES AND PARTICLE SIZE EFFECTS ON THE HEAT CAPACITY OF SOLIDS

1955 ◽  
Vol 33 (6) ◽  
pp. 1079-1087 ◽  
Author(s):  
D. Patterson
Keyword(s):  
Particle Size ◽  
Heat Capacity ◽  
Low Temperature ◽  
Temperature Effect ◽  
Size Effects ◽  
Continuum Model ◽  
Free Boundaries ◽  
Frequency Spectra ◽  
Optical Modes ◽  
Effect Of Particle Size

The effect of particle size on the heat capacity of solids has been investigated using lattices with free boundaries as models. A monatomic lattice shows a low temperature effect associated with the acoustic modes. This can be compared with results obtained from a continuum model. With a diatomic lattice, however, an effect is also associated with the optical modes and is apparent at higher temperatures. The possibility that this latter effect can explain some recent experimental results is examined.

Thermodynamic investigations of zeolites NaX and NaY

2006 ◽  
Vol 84 (2) ◽  
pp. 134-139 ◽  
Author(s):  
Liyan Qiu ◽  
Patricia A Laws ◽  
Bi-Zeng Zhan ◽  
Mary Anne White
Keyword(s):  
Particle Size ◽  
Heat Capacity ◽  
Phase Transitions ◽  
Size Effect ◽  
Thermodynamic Stability ◽  
Aluminum Content ◽  
Particle Size Effect ◽  
Al Content ◽  
Heat Capacity Measurements ◽  
Zeolitic Materials

Understanding of the thermodynamic stability of zeolites is important in the prediction of thermodynamic equilibrium. Therefore, we have undertaken an investigation of the thermodynamic stability of the zeolites NaX and NaY through heat capacity measurements from ca. 30 to 300 K. No phase transitions were observed, and zeolite NaX does not show a significant particle size effect when the particle size is reduced to ca. 30 nm. The results show that the specific heat capacity increases with the Al content in the zeolite. Both NaX and NaY are found to be thermodynamically stable with respect to their elements because of enthalpic stabilization and with slight entropic destabilization. These data are used along with literature data for many other zeolitic materials to show that the thermodynamic stability of zeolites is enhanced with increasing aluminum content. Key words: zeolite, heat capacity, thermodynamic stability, nano effects.

Particle size effect in the low temperature reforming of methane by carbon dioxide on silica-supported Ni nanoparticles

2013 ◽  
Vol 297 ◽  
pp. 27-34 ◽  
Author(s):  
David Baudouin ◽  
Uwe Rodemerck ◽  
Frank Krumeich ◽  
Aimery de Mallmann ◽  
Kaï C. Szeto ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Particle Size ◽  
Low Temperature ◽  
Size Effect ◽  
Particle Size Effect ◽  
Ni Nanoparticles ◽  
Supported Ni

Particle size effect in nanoscale Pt3Co/C electrocatalysts for low-temperature fuel cells

2009 ◽  
Vol 4 (3-4) ◽  
pp. 170-175 ◽  
Author(s):  
I. N. Leont’ev ◽  
V. E. Guterman ◽  
E. B. Pakhomova ◽  
A. V. Guterman ◽  
A. S. Mikheikin
Keyword(s):  
Particle Size ◽  
Fuel Cells ◽  
Low Temperature ◽  
Size Effect ◽  
Particle Size Effect ◽  
Low Temperature Fuel Cells

The effect of particle size on the heat capacity of titanium dioxide

1954 ◽  
Vol 224 (1157) ◽  
pp. 228-235 ◽  
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Heat Capacity ◽  
Titanium Dioxide ◽  
Theoretical Calculations ◽  
Particle Size Effect ◽  
The Other ◽  
Optical Modes ◽  
Modes Of Vibration ◽  
Effect Of Particle Size

The heat capacities of four samples of titanium dioxide, differing in particle size, have been measured in the temperature range 12 to 270° K in order to determine the effect of particle size on the specific heat. Contrary to the prediction of existing theories, no effect attributable to a change in particle size has been found in the low-temperature region. On the other hand, above 50° K a pronounced particle-size effect is evident which may be accounted for qualitatively as an effect on the optical modes of vibration of the solid. The complexity of the titanium dioxide crystal structure precludes any quantitative theoretical calculations.

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