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Calorimeter
About: Calorimeter is a research topic. Over the lifetime, 5878 publications have been published within this topic receiving 77157 citations.
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TL;DR: In this article, the authors used a dynamic scanning calorimeter to measure specific heat, latent heat and melting temperature of the nanosalt and nanosalts over a wide range of temperature up to 773 K.
82 citations
TL;DR: Room calorimeters operated with closed-loop control with consistent 24-h mean CO2 levels and pressures can be used for accurate measurement of energy expenditure rate dynamics for a wide range of individuals.
Abstract: Large room calorimeters are capable of rapid measurements that are usually made in hoods or small rooms. We evaluated the performance gains of four calorimeters constructed with modern control systems, sample gas preparation and data processing. Calibration of the calorimeters and instruments was performed in place, with traceability to international standards. Performance was evaluated by infusion of N2-CO2 gas and 243 24-h studies of individuals. Our subjects included children weighing 20 kg and adults engaged in heavy exercise. Errors for 24-h infusion measurements (n = 23) were -0.34 +/- 1.24% for oxygen consumption rate and 0.11 +/- 0.98% for carbon dioxide production rate. Calorimeter 90% response times were 2 to 6 min over a range of oxygen consumption rates from 100 to > 4000 mL/min. Closed-loop control of supply and exhaust air flows provided consistent 24-h mean CO2 levels (0.39 +/- 0.015%) and pressures (13.2 +/- 4.4 Pa). Room calorimeters operated with closed-loop control can be used for accurate measurement of energy expenditure rate dynamics for a wide range of individuals.
82 citations
TL;DR: In this article, the design and construction of a modified isothermal flow calorimeter with a reproducibility of better than 0.5 per cent is described, which was used to measure H m E for (ethanol + water) at 298.15 K and pressures of 0.4, 5, 10, and 15 MPa.
81 citations
TL;DR: In this article, a heat of combustion calorimeter was developed in which it was possible to rotate the bomb after the combustion to obtain accurate heat of formation data for organic sulfur compounds.
Abstract: To obtain accurate heat of formation data for organic sulfur compounds, a heat of combustion calorimeter has been developed in which it is possible to rotate the bomb after the combustion. Rotation of the bomb tends to produce a thermodynamically defined final state for the combustion process, because the stirring action hastens the attainment of (a) homogeneity of the bomb solution and (b) equilibrium with respect to solution of the bomb gases in the solution. Uncertainties inherent in the use of conventional calorimeters for heat of combustion studies of sulfur compounds are thereby minimized. Results, comparable in precision to those possible in similar studies of hydrocarbons, have been obtained. The indications are that the rotating bomb will have many other applications in combustion calorimetry, particularly in cases in which it is advisable to add a large amount of liquid to the bomb. The following values in kcal. mole/sup -1/ are reported for the standard heats of formation, ..delta..H/sup 0//sub f/(25/sup 0/), of some organic sulfur compounds from graphite, hydrogen gas and rhombic sulfur: 1-pentanethiol, (1) -36.1, (g) -26.2; 3-thiapentane, (1) -28.9, (g) -20.4; 2-methyl-2-propanethiol, (1) -33.7, (g) -26.3; thiacyclopentan, (1) -17.3, (g) -8.0; thiacyclobutane, (1) +6.2, (g) +14.7; and thianthrene,more » (s) +43.6.« less
81 citations
TL;DR: In this paper, temperature-modulated differential scanning calorimetry of first-order transitions has led to many new observations, some of which involve non-linear processes or deal with transformations of practically instantaneous response.
81 citations