Molar entropies at 80 K of sub-monolayer nitrogen films adsorbed on graphite from heat capacity measurement

1988 ◽  
Vol 66 (4) ◽  
pp. 703-705 ◽  
Author(s):  
Akira Inaba ◽  
Hideaki Chihara
Keyword(s):  
Heat Capacity ◽  
Isosteric Heat ◽  
Heat Capacity Measurement ◽  
Graphite Surface ◽  
Exfoliated Graphite ◽  
Capacity Measurement ◽  
Isosteric Heat Of Adsorption ◽  
Heats Of Adsorption ◽  
Energetic Heterogeneity ◽  
Good Agreement

The heat capacity of nitrogen adsorbed on an exfoliated graphite (Grafoil GTA) has been measured between 3 and 80 K at surface coverages of [Formula: see text] The molar entropies are determined at 80 K. The effect of energetic heterogeneity of the graphite surface seems to be much less than that expected from the measurements of heats of adsorption. The isosteric heat of adsorption at zero coverage qst(0), for a hypothetical homogeneous graphite surface is estimated to be 9.8 kJ mol−1 at 80 K, which is in good agreement with that obtained from simulations performed at 75 K, 9.9 kJ mol−1.

Experimental Study on the Specific Heat Capacity Measurement of Water-Based Al2O3-Cu Hybrid Nanofluid by using Differential Thermal Analysis Method

2019 ◽  
Vol 15 ◽  
Author(s):  
Andaç Batur Çolak ◽  
Oğuzhan Yıldız ◽  
Mustafa Bayrak ◽  
Ali Celen ◽  
Ahmet Selim Dalkılıç ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermophysical Properties ◽  
Volume Concentration ◽  
Pure Water ◽  
Heat Capacity Measurement ◽  
Experimental Results ◽  
Hybrid Nanofluid ◽  
Capacity Measurement

Background: Researchers working in the field of nanofluid have done many studies on the thermophysical properties of nanofluids. Among these studies, the number of studies on specific heat are rather limited. In the study of the heat transfer performance of nanofluids, it is necessary to increase the number of specific heat studies, whose subject is one of the important thermophysical properties. Objective: The authors aimed to measure the specific heat values of Al2O3/water, Cu/water nanofluids and Al2O3-Cu/water hybrid nanofluids using the DTA method, and compare the results with those frequently used in the literature. In addition, this study focuses on the effect of temperature and volume concentration on specific heat. Method: The two-step method was used in the preparation of nanofluids. The pure water selected as the base fluid was mixed with the Al2O3 and Cu nanoparticles and Arabic Gum as the surfactant, firstly mixed in the magnetic stirrer for half an hour. It was then homogenized for 6 hours in the ultrasonic homogenizer. Results: After the experiments, the specific heat of nanofluids and hybrid nanofluid were compared and the temperature and volume concentration of specific heat were investigated. Then, the experimental results obtained for all three fluids were compared with the two frequently used correlations in the literature. Conclusion: Specific heat capacity increased with increasing temperature, and decreased with increasing volume concentration for three tested nanofluids. Cu/water has the lowest specific heat capacity among all tested fluids. Experimental specific heat capacity measurement results are compared by using the models developed by Pak and Cho and Xuan and Roetzel. According to experimental results, these correlations can predict experimental results within the range of ±1%.

Heat-capacity measurement of R2BaNiO5 (R = Y, Ho, Er) oxides

1992 ◽  
Vol 104-107 ◽  
pp. 619-620 ◽  
Author(s):  
M. Castro ◽  
R. Burriel ◽  
A. Salinas-Sánchez ◽  
R. Sáez-Puche
Keyword(s):  
Heat Capacity ◽  
Heat Capacity Measurement ◽  
Capacity Measurement

Development of Heat Capacity Measurement System under High Pressure

2007 ◽  
Vol 46 (5A) ◽  
pp. 3090-3095 ◽  
Author(s):  
Fumiaki Tomioka ◽  
Izuru Umehara ◽  
Takashi Ono ◽  
Masato Hedo ◽  
Yoshiya Uwatoko ◽  
...  
Keyword(s):  
Heat Capacity ◽  
High Pressure ◽  
Measurement System ◽  
Heat Capacity Measurement ◽  
Capacity Measurement

A phase transition in doped I. Heat capacity measurement

1977 ◽  
Vol 64 (1-2) ◽  
pp. 189-194 ◽  
Author(s):  
Inaba Hideaki ◽  
Ono Shoichi ◽  
Naito Keiji
Keyword(s):  
Phase Transition ◽  
Heat Capacity ◽  
Heat Capacity Measurement ◽  
Capacity Measurement
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