Specific heat of sodium nitrate and silver nitrate by medium high temperature adiabatic calorimetry

1967 ◽  
Vol 20 (1) ◽  
pp. 1 ◽  
Author(s):  
VC Reinsborough ◽  
FEW Wetmore
Keyword(s):  
Specific Heat ◽  
Silver Nitrate ◽  
Sodium Nitrate ◽  
Thermal Hysteresis ◽  
Adiabatic Calorimeter ◽  
Drop Calorimetry ◽  
Calorimetric Technique ◽  
Temperature Ranges ◽  
Solid Liquid ◽  
Heat Of Transformation

��� A relatively simple adiabatic calorimeter for use in the temperature range 50-350� was constructed and used to measure the specific heat of sodium nitrate from 150 to 300� and silver nitrate from 70 to 250�. Each salt undergoes a solid-solid and a solid-liquid transformation in these temperature ranges. The Cp values for sodium nitrate agreed within the calculated experimental error of �0.2% with those of Sokolov and Shmidt1 but the silver nitrate showed a large discrepancy with those of Janz and Kelly2 obtained by drop calorimetry for the 160-210� region, where thermal hysteresis may have occurred in the drop calorimetric technique. The heat of transformation for the solid-solid transition in silver nitrate at 159.4� was found to be 561�4 cal mole-1.

Thermoelectric Studies of Silver Nitrate in Sodium Nitrate – Potassium Nitrate Eutectic Melt

1971 ◽  
Vol 49 (12) ◽  
pp. 2044-2047
Author(s):  
L. G. Boxall ◽  
K. E. Johnson
Keyword(s):  
Seebeck Coefficient ◽  
Silver Nitrate ◽  
Mole Fraction ◽  
Sodium Nitrate ◽  
Nitrate Concentration ◽  
Potassium Nitrate ◽  
Silver Nitrate Concentration ◽  
Eutectic Melt

The Seebeck coefficient, εT, of the thermocell Ag(T)/AgNO3 in NaNO3 − KNO3/Ag (T + ΔT) was measured as a function of silver nitrate concentration and temperature. Extrapolation of the results to unit mole fraction, N, of AgNO3 gave the value εT0 = − 277.5 − 0.136T °C (µV deg−1).For several mixed melts of AgNO3 and an alkali nitrate the function [Formula: see text] was calculated and shown to be linear in N. P was extrapolated to finite values for the pure alkali nitrates.

Role of Vibration-Induced Streaming in Float-Zone Crystal Growth

2000 ◽  
Author(s):  
Amrutur V. Anilkumar ◽  
Richard N. Grugel
Keyword(s):  
Sodium Nitrate ◽  
Silicone Oil ◽  
Surface Flow ◽  
Thermocapillary Flow ◽  
Return Flow ◽  
Zone Length ◽  
Float Zone ◽  
Streaming Velocity ◽  
Solid Liquid Interface ◽  
Solid Liquid

Abstract The streaming induced in a short vertical liquid column by the vibration of one of the supporting end walls has been utilized in this novel study. Vibration essentially drives a surface flow in the zone away from the vibrating wall, with the return flow in the bulk towards the wall. Preliminary measurements of the surface streaming velocity show that it increases with the frequency and amplitude of vibration and the zone length, and decreases with the viscosity of the zone liquid. This controlled surface streaming has been employed to balance a opposing, steady thermocapillary flow in model half-zones of silicone oil and Sodium Nitrate. In addition, in a float-zone solidification experiment with Sodium Nitrate - Barium Nitrate eutectic as the study material, we have demonstrated that streaming-based balancing of thermocapillary flow promotes a planar solid/liquid interface and a uniform microstructure.

scholarly journals X-ray investigation of the structure transition of methane at the λ point

1939 ◽  
Vol 171 (947) ◽  
pp. 569-578 ◽  
Keyword(s):  
Crystal Structure ◽  
Specific Heat ◽  
Structure Transition ◽  
Sharp Maximum ◽  
Critical Range ◽  
Other Substances ◽  
Strong Resemblance ◽  
Transition Points ◽  
Λ Point ◽  
Heat Of Transformation

A great deal of work has been done on the crystal structure of long-chain hydrocarbons and their behaviour near transition points. These transitions are as a rule quite normal, in so far as the transition is marked by the liberation or binding of a definite heat of transformation and change in structure. The simplest of the hydrocarbons, methane, shows a change from the ordinary behaviour. At 20.4° K a so-called transition of the second kind (Clusius and Perlick 1933) takes place, of which an abnormal rise of the specific heat is typical. This begins at low temperatures where the specific heat rises at first slowly to reach a very sharp maximum at 20.4° and then falls abruptly to somewhat normal values. No latent heat appears. The effect bears a strong resemblance to the λ point of helium and other substances. The crystal structure of methane has been directly determined by two authors (McLennan and Plummer 1929; Mooy 1931) of whom only Mooy paid special attention to any possible change of structure at the transition point. He observed no change in the critical range. The structure is cubic face-centred according to both authors, but we would like to point out that Mooy’s table contains two lines which do not belong to reflexions from that lattice and which he labelled “parasitic lines”.

Measurement of Total Hemispherical Emittance and Specific Heat of Aluminum and Inconel 718 by a Calorimetric Technique

2005 ◽  
Vol 128 (3) ◽  
pp. 302-306 ◽  
Author(s):  
Giovanni Tanda ◽  
Mario Misale
Keyword(s):  
Heat Transfer ◽  
Specific Heat ◽  
Radiative Heat Transfer ◽  
Inconel 718 ◽  
Radiative Heat ◽  
Time History ◽  
Inconel 718 Alloy ◽  
Joule Effect ◽  
Calorimetric Technique ◽  
Total Hemispherical Emittance

An apparatus for the measurement of the total hemispherical emittance and specific heat of metals has been developed. The measurement principle is based on the calorimetric technique: the sample, heated by Joule effect and placed in a vacuum chamber, exchanges radiative heat transfer with the walls of the container, kept at a relatively low temperature. Emittance is deduced from the radiative heat transfer laws at the steady state. When the heating power is switched off, the specific heat of the sample can be recovered from the time history of the sample temperature during the cooling transient. Measurements have been performed on samples of aluminum Anticorodal alloy and Inconel 718 alloy under different surface conditions in the 350-635K range.

The specific heat of lithium from 20 to 300 °K: the martensitic transformation

1960 ◽  
Vol 254 (1279) ◽  
pp. 444-454 ◽  
Keyword(s):  
Martensitic Transformation ◽  
Specific Heat ◽  
Atomic Weight ◽  
Phase Region ◽  
Two Phase ◽  
Self Diffusion ◽  
Debye Temperatures ◽  
Order Of Magnitude ◽  
Two Phases ◽  
Heat Of Transformation

Measurements on lithium of atomic weight 6·945 are reported. A thermal study of the martensitic transformation showed a large specific-heat anomaly in the reversion region and a specific heat dependent upon thermal history in the two-phase region. The high-temperature end of the reversion anomaly shows time effects which suggest that the process here is controlled by a spectrum of activation energies of the same order of magnitude as that for self diffusion. With some assumptions the heat of transformation from hexagonal closepacked to body-centered cubic lithium is deduced to be about 14 cal/g atom and the Debye temperatures of the two phases at 60 °K are 390 and 371 °K respectively. The entropy at 298·15 °K is 6·95 ±0·04 cal/°K g atom.

scholarly journals On the Determination of Molar Heat Capacity of Transition Elements: From the Absolute Zero to the Melting Point

2021 ◽  
Author(s):  
Ivaldo Leão Ferreira ◽  
José Adilson de Castro ◽  
Amauri Garcia
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Molar Heat Capacity ◽  
Materials Science ◽  
Solid Phase ◽  
Transition Elements ◽  
Phase Nucleation ◽  
New Formulation ◽  
Solid Liquid

Molar specific heat is one of the most important thermophysical properties to determine the sensible heat, heat of transformation, enthalpy, entropy, thermal conductivity, and many other physical properties present in several fields of physics, chemistry, materials science, metallurgy, and engineering. Recently, a model was proposed to calculate the Density of State by limiting the total number of modes by solid–liquid and solid–solid phase nucleation and by the entropy associated with phase transition. In this model, the new formulation of Debye’s equation encompasses the phonic, electronic, and rotational energies contributions to the molar heat capacity of the solids. Anomalies observed in the molar specific heat capacity, such as thermal, magnetic, configurational transitions, and electronic, can be treated by their transitional entropies. Model predictions are compared with experimental scatter for transitional elements.

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