An anomaly in the specific heat below 3 °K of copper containing hydrogen

1969 ◽  
Vol 47 (14) ◽  
pp. 1485-1491 ◽  
Author(s):  
Neil Waterhouse
Keyword(s):  
Specific Heat ◽  
Molecular Hydrogen ◽  
Pure Copper ◽  
Solid Hydrogen ◽  
Rotational State ◽  
Experimental Results ◽  
Ortho Hydrogen ◽  
Temperature Range ◽  
A Value ◽  
Heat Curve

The specific heat of copper heated in hydrogen at 1040 °C has been measured over the temperature range 0.4 to 3.0 °K and found to be anomalous. The anomaly occurs in the same temperature range as the solid hydrogen λ anomaly which, in conjunction with evidence of ortho to para conversion of hydrogen in the sample, suggests the presence of molecular hydrogen in the copper. The anomaly reported by Martin for "as-received" American Smelting and Refining Company (ASARCO) 99.999+ % pure copper has been briefly compared with the present results. The form of the anomaly produced by the copper-hydrogen specimen has been compared with Schottky curves using the simplest possible model, that for two level splitting of the degenerate J = 1 rotational state of the ortho-hydrogen molecule.Maintenance of the copper-hydrogen sample at ~20 °K for approximately 1 week removed the "hump" in the specific heat curve. An equation of the form Cp = γT + (464.34/(θ0c)3)T3 was found to fit these experimental results and produced a value for γ which had increased over that for vacuumannealed pure copper by ~2%.

scholarly journals The Specific Heat of Saline Ice

1975 ◽  
Vol 14 (72) ◽  
pp. 459-465 ◽  
Author(s):  
Bharat Dixit ◽  
E. R. Pounder
Keyword(s):  
Theoretical Model ◽  
Melting Point ◽  
Specific Heat ◽  
Experimental Results ◽  
Temperature Range ◽  
Calorimetric Experiment

A calorimetric experiment was performed to determine empirically the dependence of the specific heat of ice with salinity 0-10‰ over the temperature range from –23° C to the melting point The experimental results agree with the theoretical model determined by Schwerdtfeger (1963) for calculating the specific heat except within several degrees of the melting point and for very pure ice.

scholarly journals Spezifische Wärme von CeCl3·7 H2O zwischen 1,1 und 3,3°K

1967 ◽  
Vol 22 (12) ◽  
pp. 1999-2001 ◽  
Author(s):  
S. Hüfner ◽  
R. v. Klot ◽  
F. Küch ◽  
G. Weber
Keyword(s):  
Triplet State ◽  
Specific Heat ◽  
Antiferromagnetic Coupling ◽  
Energy Separation ◽  
Temperature Range ◽  
A Value ◽  
Lower Singlet

The specific heat of monoclinic CeCl3 · 7 H2O was measured in the temperature range between 1,1 and 3,3°K. Assuming that the cerium-ions are arranged in isolated pairs with isotropic and antiferromagnetic coupling a value of k · 1,20°K is derived from the data for the energy separation between the lower singlet and the upper triplet state.

Strain Effects on the Tunneling Levels of KCl: Li

1970 ◽  
Vol 25 (12) ◽  
pp. 1844-1855 ◽  
Author(s):  
B. Dischler
Keyword(s):  
Specific Heat ◽  
Average Energy ◽  
Preceding Paper ◽  
Experimental Results ◽  
Strain Effects ◽  
Schottky Anomaly ◽  
A Value ◽  
Internal Strains

Abstract The effects of internal strains on the tunneling levels of KCl : Li are investigated quantitatively. The method, as developed in a preceding paper by TIMME, DISCHLER, and ESTLE1 , is further improved here. A reinterpretation is presented for two experimental results reported in the literature: the resonances in the phonon spectrometer curve and the specific heat (Schottky) anomaly. The agreement with these experiments and also with paraelectric resonance is good, if isotropic strains are assumed with an average energy of 20 GHz, corresponding to a stress of 30 ± 10 kp/cm2 . For the cube edge tunneling interaction a value of 10 GHz is derived.

INVESTIGATION OF THE ENTROPY AND SPECIFIC HEAT CAPACITY OF GaN USING INCOMPLETE GAMMA FUNCTIONS

2008 ◽  
Vol 22 (30) ◽  
pp. 5349-5355 ◽  
Author(s):  
SAVAŞ SÖNMEZOǦLU
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Experimental Results ◽  
Analytical Relation ◽  
Gamma Functions ◽  
Temperature Range ◽  
Incomplete Gamma Functions ◽  
Theoretical Results ◽  
Good Agreement

The aim of this paper is to provide validity and reliable analytical relation for the thermodynamic functions calculated in terms of the Debye temperature using incomplete gamma functions, and examines the entropy and specific heat capacity of hexagonal single crystals of GaN in the 0–1800 K temperature range. The obtained results have been compared with the corresponding experimental and theoretical results. Our results are in excellent agreement with the theoretical results over the entire temperature range. It has also shown that at low temperature, our results are in very good agreement with the experimental results, however, at high temperature, our results are lower than other experimental results.

scholarly journals The Specific Heat of Saline Ice

1975 ◽  
Vol 14 (72) ◽  
pp. 459-465 ◽  
Author(s):  
Bharat Dixit ◽  
E. R. Pounder
Keyword(s):  
Theoretical Model ◽  
Melting Point ◽  
Specific Heat ◽  
Experimental Results ◽  
Temperature Range ◽  
Calorimetric Experiment

A calorimetric experiment was performed to determine empirically the dependence of the specific heat of ice with salinity 0-10‰ over the temperature range from –23° C to the melting point The experimental results agree with the theoretical model determined by Schwerdtfeger (1963) for calculating the specific heat except within several degrees of the melting point and for very pure ice.

The specific heat of pure copper and of some dilute copper + iron alloys showing a minimum in the electrical resistance at low temperatures

1961 ◽  
Vol 263 (1315) ◽  
pp. 494-507 ◽  
Keyword(s):  
Specific Heat ◽  
Electrical Resistance ◽  
Low Temperatures ◽  
Pure Copper ◽  
Iron Alloys ◽  
Absolute Zero ◽  
Iron Ions ◽  
Temperature Range ◽  
Dilute Alloys ◽  
Resistance Minimum

The specific heat of pure copper and of some dilute alloys of iron in copper, containing approximately 0.05, 0.1 and 0.2at. % iron, have been measured in the temperature range 0.4 to 30 °K. The electrical resistance of the copper + iron alloys has been measured from 0.4 to 80 °K. The alloys show specific-heat anomalies which probably extend from the absolute zero of temperature to the region of the minimum in electrical resistance. The entropy contents of the anomalies lie close to the value R In 2 per mole of iron suggesting that only two energy states of the iron ions are involved in the resistance minimum phenomena. The results are discussed in relation to existing theories.

THE SPECIFIC HEAT OF COPPER FROM 20° TO 300 deg;K

1960 ◽  
Vol 38 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Douglas L. Martin
Keyword(s):  
Specific Heat ◽  
Pure Copper ◽  
Annealed Sample ◽  
Rolled Material ◽  
Temperature Range ◽  
Specific Heats ◽  
Commercially Pure ◽  
Cold Rolled ◽  
Cold Worked ◽  
Annealed Copper

The specific heats of commercially pure cold-rolled copper and of annealed and heavily cold-worked 99.999% pure copper have been measured in the temperature range 20° to 300 deg;K. When results are averaged over the whole temperature range of measurement the specific heat of the pure cold-worked copper is about 0.15% above that of the pure annealed sample while results for the commercially pure cold-rolled material lie in an intermediate position. Results on a given sample are reproducible within 0.05%. The entropy of pure annealed copper at 298.15 deg;K is 7.92 ± 0.04 cal/°K g-atom.

Interaction of H2O, O2 and H2 with Proton Conducting Oxides Based on Lanthanum Scandates

2019 ◽  
pp. 88-100
Author(s):  
A. S. Farlenkov ◽  
N. A. Zhuravlev ◽  
Т. A. Denisova ◽  
М. V. Ananyev
Keyword(s):  
Water Vapor ◽  
Partial Pressure ◽  
Gas Phase ◽  
Molecular Hydrogen ◽  
Proton Magnetic Resonance ◽  
Partial Pressure Of Oxygen ◽  
Proton Conducting ◽  
Conducting Oxides ◽  
Temperature Range ◽  
Apparent Level

The research uses the method of high-temperature thermogravimetric analysis to study the processes of interaction of the gas phase in the temperature range 300–950 °C in the partial pressure ranges of oxygen 8.1–50.7 kPa, water 6.1–24.3 kPa and hydrogen 4.1 kPa with La1–xSrxScO3–α oxides (x = 0; 0.04; 0.09). In the case of an increase in the partial pressure of water vapor at a constant partial pressure of oxygen (or hydrogen) in the gas phase, the apparent level of saturation of protons is shown to increase. An increase in the apparent level of saturation of protons of the sample also occurs with an increase in the partial pressure of oxygen at a constant partial pressure of water vapor in the gas phase. The paper discusses the causes of the observed processes. The research uses the hydrogen isotope exchange method with the equilibration of the isotope composition of the gas phase to study the incorporation of hydrogen into the structure of proton-conducting oxides based on strontium-doped lanthanum scandates. The concentrations of protons and deuterons were determined in the temperature range of 300–800 °C and a hydrogen pressure of 0.2 kPa for La0.91Sr0.09ScO3–α oxide. The paper discusses the role of oxygen vacancies in the process of incorporation of protons and deuterons from the atmosphere of molecular hydrogen into the structure of the proton conducting oxides La1–xSrxScO3–α (x = 0; 0.04; 0.09). The proton magnetic resonance method was used to study the local structure in the temperature range 23–110 °C at a rotation speed of 10 kHz (MAS) for La0.96Sr0.04ScO3–α oxide after thermogravimetric measurements in an atmosphere containing water vapor, and after exposures in molecular hydrogen atmosphere. The existence of proton defects incorporated into the volume of the investigated proton oxide from both the atmosphere containing water and the atmosphere containing molecular hydrogen is unambiguously shown. The paper considers the effect of the contributions of the volume and surface of La0.96Sr0.04ScO3–α oxide on the shape of the proton magnetic resonance spectra.

THE ENTHALPY-POROSITY METHOD WITH A RECTANGULAR SPECIFIC HEAT CURVE

2018 ◽  
Author(s):  
Wim Beyne ◽  
Bernd Ameel ◽  
Alvaro de Gracia ◽  
Gabriel Zsembinszki ◽  
Luisa F Cabeza ◽  
...  
Keyword(s):  
Specific Heat ◽  
Heat Curve

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%.

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