Showing papers on "Calorimeter published in 1985"
TL;DR: A three chamber, indirect calorimeter which operates over the range of 5 to 40°C was constructed for use on swine, sheep and baby calves as discussed by the authors, which measured 02 consumption and C02 and CH4 production at 10-min intervals, and provided an average measurement of gaseous exchange volumes over the total period of operation.
Abstract: Athree chamber, indirect calorimeter which operates over the range of 5 to 40° C was constructed for use on swine, sheep and baby calves. The calorimeter measures 02 consumption and C02 and CH4 production at 10-min intervals, and provides an average measurement of gaseous exchange volumes over the total period of operation. A range of 98.0 to 103.5% of the expected quantity of gaseous exchange was measured with the calorimeter system as the result of combustion of alcohol using modified alcohol lamps in the calorimeters. Errors in oxygen analysis, gas volume measurement and barometric pressure account for 89% of the total system error. Expected system error ranges from 3.45 to 5.58% depending on the oxygen concentration maintained in the calorimeter chamber.
67 citations
TL;DR: In this paper, the DISC (differential, isoperibol, scanning calorimeter) is described for low-temperature calorimetric measurements in the temperature range 4 K T.
49 citations
IBM1
TL;DR: In this paper, the use of pyroelectric polyvinylidene fluoride calorimeters for the measurement of thermal diffusivities of thin films is described, and the potential of this detection scheme combined with photothermal excitation is demonstrated on polymer films with thickness in the 1 μm range.
Abstract: The use of pyroelectric polyvinylidene fluoride calorimeters for the measurement of thermal diffusivities of thin films is described. The potential of this detection scheme combined with photothermal excitation is demonstrated on polymer films with thickness in the 1 μm range.
45 citations
TL;DR: In this article, the relative enthalpy of pure, polycrystalline aluminum (NBS Standard Reference Material 44f, for the freezing point of aluminum on IPTS-68) has been measured over the temperature range 273 to 929 K.
Abstract: The relative enthalpy of pure, polycrystalline aluminum (NBS Standard Reference Material 44f, for the freezing point of aluminum on IPTS-68) has been measured over the temperature range 273 to 929 K. The enthalpy measurements were made in a precision isothermal phase-change calorimeter and are believed to have an inaccuracy not exceeding 0.2%. Pt-10Rh alloy and quartz glass were used as the encapsulating materials. The enthalpy data for Al(s) and SiO2(l) have been fitted by the method of least squares with cubic polynomial functions of temperature. Heat capacity data for Al(s), derived from these polynomials, have been smoothly merged using a spline technique to the most reliable low-temperature heat capacity data for Al(s) below 273 K. The merged data are compared with corresponding data from the literature as well as with published critical compilations of heat capacity data for Al(s). A new table of thermodynamic functions for Al(s) has been derived. A theoretical interpretation of the results apears in the following paper.
43 citations
TL;DR: In this article, a new type of flow microcalorimeter for measuring heat capacities at constant pressure of liquids and solutions was constructed, which is similar in design to Picker's except for the flow system, which consists of two syringe type of pumps and two flowing paths in each flow cell.
40 citations
TL;DR: An automatic calorimeter, based on gravimetric principles, for studies on the energy metabolism of the fowl, with simultaneous recording of the physical activity, shows a good fit in a linear regression equation, from which resting heat production is derived.
Abstract: 1. An automatic calorimeter, based on gravimetric principles, for studies on the energy metabolism of the fowl, with simultaneous recording of the physical activity, is described. 2. In order to reduce errors in the determination of heat production to below 3% a three hour experimental period is necessary. The length of this period in comparison to that of the Pettenkofer system is discussed. 3. The relation between heat production and physical activity shows a good fit in a linear regression equation, from which resting heat production is derived. 4. Up to 25% of the total heat production is related to physical activity, mainly during the day‐time.
36 citations
TL;DR: A water-cooled heat exchange calorimeter for the measurement of enthalpy increments of fluids up to 700 K and 15 MPa has been constructed in this paper, and the results showed that the results were in agreement with steam tables to within 0.97 per cent.
30 citations
TL;DR: A heat-conduction or Tian type isothermal microcalorimeter to measure the rate of heat liberation during the hydration of cement has been designed and constructed in this paper.
28 citations
TL;DR: In this article, a new calorimeter of the heatflow type designed to measure the differential heats of adsorption of gases on high surface area solids (e.g., catalysts) is described.
Abstract: A new calorimeter of the heat‐flow type designed to measure the differential heats of adsorption of gases on high surface area solids (e.g., catalysts) is described. Heat flow is measured using conventional thermopiles; the signals from which are amplified, digitized, and then sent to a laboratory computer for ease of data handling and analysis. The instrument allows conventional isotherm and heat data to be collected concomitantly. Other useful information obtained includes qualitative data regarding the rate at which processes take place, the total amount of gas chemisorbed, and the integrated value of the heat of adsorption. The instrument is capable of operating at temperatures from 273 to 373 K. One major advance over previous designs is that the dosing gas is allowed to thermally equilibrate before entering the sample chamber. The results of a simple study of the differential heats of adsorption of oxygen on a high surface area carbon material are presented. This study demonstrates the reliability and utility of the instrument.
24 citations
TL;DR: In this article, a calorimeter of the adiabatic type has been constructed for measurements of the heat capacity between 10 and 310 K. The system allowed unattended operation for 15 h.
22 citations
TL;DR: In this article, the profiles of temperature and state of cure developed through the cross-section of the sample have been calculated, as well as the heat flux obtained through the sample-calorimeter interface.
TL;DR: An automated low temperature adiabatic calorimeter for solid samples is described in this paper, which operates in the 10-370 K temperature range with an stablished accuracy of 0.1% in C p measurements.
TL;DR: A pyroelectric enthalpimetric calorimeter for the H-O reaction was constructed using Pd and Au electrodes on a 2.5 cm−diam, 0.3 mm−thick LiTaO3 wafer as discussed by the authors.
Abstract: A pyroelectric enthalpimetric calorimeter for the H‐O reaction was constructed using Pd and Au electrodes on a 2.5‐cm‐diam, 0.3‐mm‐thick LiTaO3 wafer. The counter (or common) electrode was of Au. The detector was placed in a chamber and various gases were admitted at pressures slightly above atmospheric. 100 ppm H2 in N2 was used as the hydrogen source and pure O2 as the oxygen source. A thermal signature was obtained on the Pd electrode that was confirmed by a thermocouple attached to the pyroelectric calorimeter. A delayed thermal signature was observed on the Au electrode resulting from thermal diffusion in the LiTaO3 substrate of the heat generated at the Pd electrode. The results on the H‐O reaction are in general agreement with the literature on Pd metal oxide semiconductor (MOS) structures. The results demonstrate the utility of the pyroelectric calorimeter.
TL;DR: In this article, the authors measured the heat release from polycrystalline copper (oxygen-free, 4N purity) after cooling toT = 1.3 K in a calorimeter.
Abstract: The heat release from polycrystalline copper (oxygen-free, 4N purity) after cooling toT=1.3 K was measured in a calorimeter with a parasitic heat leak of about 1.5 pW/g. Its relaxation and the dependence of the total heat released on the temperature of the specimen before cooling to 1.3 K agree well with the hypothesis of the ortho-para conversion of molecular hydrogen precipitated in copper and behaving as free hydrogen. A temperature dependence of the relaxation time and an additional “fast” heat release just after cooling were observed.
TL;DR: In this article, a novel bench-scale calorimeter, which is based on a heat-flux principle and modified to accommodate biol. reactions, was evaluated for detg. the heat evolution rate of an aerobic culture of the yeast Kluyveromyces fragilis grown on lactose.
TL;DR: In this paper, the modified BWR equation-of-state developed by Brute specifically for coal liquids gave the best representation of vapour pressure data, and an empirical method involving a simple BP relationship combined with the Watson equation was used to predict latent heat data.
Abstract: Coal liquids produced from SRC-II processing of Powhatan No.6 bituminous coal were distilled into a number of narrow-boiling cuts. Vapour pressure measurements were carried out on 6 cuts at temperatures from 267 to 788 K and pressures to 3.6 MPa. Heats of vaporisation were measured in a flow calorimeter on these same fractions at temperatures from 366 to 755 K. It was found that the modified BWR equation-of-state developed by Brute specifically for coal liquids gave the best representation of vapour pressure data. An empirical method involving a simple BP relationship combined with the Watson equation gave the best predictions of latent heat data.
TL;DR: The construction and performance of a 24-m3 direct heat-sink calorimeter for continuous measurement of evaporative and sensible heat loss in human subjects and extensive use of real-time processing made it possible to solve response-time and stability problems associated with the large volume.
Abstract: The construction and performance of a 24-m3 direct heat-sink calorimeter for continuous measurement of evaporative and sensible heat loss in human subjects are described. Extensive use of real-time processing for compensation of physical time constants and delays made it possible to solve response-time and stability problems associated with the large volume. The performance characteristics of the calorimeter are 1) a linear response between 0 and 320 W (471 g . h-1) for evaporative heat with a precision of 4.0-0.6% in the range 25-100 W, 2) a linear response between 0 and 280 W for sensible heat with a precision of 1.4-0.2% in the range 50-200 W, 3) a stability corresponding to a drift of less than 0.6 W (24 and 72 h) on both evaporative and sensible heat outputs and 24- and 72-h standard deviations (values every 2 min) of 0.3 and 0.4 W for evaporative heat and 0.6 and 0.7 W for sensible heat, 4) response times (95%) of 15 min for both evaporative and sensible heat, 5) independency on the position of the calibration source within the chamber, 6) no measurable "cross talk" between evaporative and sensible heat inputs, 7) negligible dependency of the external air humidity between 14 and 70%, and 8) operating temperature range from 18 to 30 degrees C. More than 40 experiments of 25-h duration with human subjects have been carried out. In no case was any discomfort recorded. An example of the 25-h continuous evaporative and sensible heat output tracing of one experiment is given.
TL;DR: The modified heat-flux, computer-assisted bench calorimeter is sensitive enough to permit accurate and easy monitoring of the heat dissipated by a weakly exothermic culture of Escherichia coli under stirred and aerobic conditions.
TL;DR: The use of a twin-cell differential titration calorimeter is described which utilizes small volumes of modest concentrations of materials and yields data of good precision and has been applied to the ionization of EDTA and its calcium complex.
15 Nov 1985-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, the authors calculated the transition effect from EGS3 shower Monte Carlo simulations for a liquid argon calorimeter and found that it is energy independent and can easily reduce the signal of electromagnetic showers to 70%.
Abstract: The transition effect was calculated from EGS3 shower Monte Carlo simulations for a liquid argon calorimeter. The transition effect was found to be energy independent and can easily reduce the signal of electromagnetic showers to 70%. The effect on the e/h ratio of liquid argon calorimeters is discussed.
TL;DR: A Perkin-Elmer DSC-2 scanning calorimeter was operated by means of a PDP-11/34 computer with time-shared scanner and voltmeter and it was found that Ne, rather than He, should be used as a purge gas, that scans should always be started at a standardized liquid nitrogen level, and that gas flow to the dry box should be stopped during measurements.
Abstract: A Perkin-Elmer DSC-2 scanning calorimeter was operated by means of a PDP-11/34 computer with time-shared scanner and voltmeter. Special attention was paid to the problems of measurement below room temperature down to the low-temperature limit. It was found that Ne, rather than He, should be used as a purge gas, that scans should always be started at a standardized liquid nitrogen level, and that gas flow to the dry box should be stopped during measurements. Results on benzoic acid were then accurate to 0.6 % from 120 to 300 K. The specific heat of antimony was measured in the temperature interval 120–720 K.
TL;DR: In this paper, a recently developed calorimeter is described which measures the total heat produced by a one kilogram sample of coal under controlled oxidizing conditions, which is measured by a series of thermistors situated in the coal.
Abstract: A recently developed calorimeter is described which measures the total heat produced by a one kilogram sample of coal under controlled oxidizing conditions. Essentially the calorimeter measures the maximum temperature rise produced by a sample of coal in a dynamic oxygen atmosphere which is held at predetermined constant moisture content. The observed temperature rise is proportional to the heat generated during the initiation of the oxidation process and is measured by a series of thermistors situated in the coal. The magnitude of this temperature rise effectively determines the self heating propensity of the coal. The sample compartment of this apparatus is designed to eliminate any thermal gradients within the coal sample which may lead to non-uniform temperature rises. This apparatus enables the reproducible measurement of a coal's self heating propensity, in terms of time-temperature curves, to be made under different environmental conditions of humidity, temperature and oxygen content. The calorimet...
TL;DR: Results lead to the conclusion that both materials (cryolite and zinc sulfide) used in the preparation of the coatings contribute significantly to the absorptance of the filters and that interference effects in the substrate must be taken into account, at least at the central wavelengths of the passband region.
Abstract: The design and construction of a wavelength scanning laser calorimeter, for the measurement of absorptance in optical coatings, are described. Preliminary measurements of the absorptance of narrowband spectral filters are presented and are used to illustrate the versatility of the instrument in terms of its large spectral range and sensitivity. Results lead to the conclusion that both materials (cryolite and zinc sulfide) used in the preparation of the coatings contribute significantly to the absorptance of the filters and that interference effects in the substrate must be taken into account, at least at the central wavelengths of the passband region.
TL;DR: In this article, a method of calculation has been given for the determination of solution and reaction heats in a constant-environment calorimeter, and the calculation of a correction term for the temperature change connected with the heat exchange of the vessel with the surroundings is the focus of this work.
TL;DR: In this article, the behavior of the calorimetric response in continuous injection devices, which are well suited for measurement of excess partial molar enthalpies at different concentrations, is analyzed by means of heat transport models.
TL;DR: In this article, a high-pressure heat-flow calorimeter suitable for measuring enthalpies of reaction and heat capacities is described, and the molar reaction enthalpy is given by Δ r H m (319 K, 1.6 MPa) = −(39.8 ± 0.4) kJ·mol −1.
TL;DR: In this paper, a microprocessor-based calibration system for a CW laser power meter has been developed, which consists of an isothermal calorimeter with a thermopile unit, an electrical, and an optical subsystem.
Abstract: A microprocessor-based calibration system for a CW laser power meter has been developed. The system consists of an isothermal calorimeter with a thermopile unit, an electrical, and an optical subsystem. Temperature control of the thermopile unit is achieved through a digital technique. The calibration of a power meter is performed using the effective efficiency of the unit as measured by a calorimeter. From error analyses, an overall accuracy has been obtained as ±1 percent in root mean square for a power level of 1 ~ 200 mW.
TL;DR: In this article, a new calorimeter system is described, in which the rate of reaction is determined simultaneously with the heat of reaction, and is particularly suitable for measurement of air/coal interactions which are responsible for self-heating and spontaneous combustion.
Abstract: A new calorimeter system is described, in which the rate of reaction is determined simultaneously with the heat of reaction. The system operates near ambient temperature and is particularly suitable for measurement of air/coal interactions which are responsible for self-heating and spontaneous combustion. These interactions are characterised by an extremely slow evolution of heat of the order of about 5*10-6 W per g of coal which changes with time requiring the instrument to remain stable over a period of several weeks. The instrument may also be suitable for investigations of self-heating of other materials which are commonly stockpiled.
TL;DR: In this article, the partial molar enthalphies of the formation of solid solution for both 2S-NbS x and 3S-nbSx phase on the NbS system has been determined.
TL;DR: In this article, the temperature-dependence of the ferromagnetic transition of Gd by alloying with La has been evaluated using an adiabatic calorimeter over a wide temperature range.
Abstract: Heat capacity measurements on h.c.p. solid solutions of lanthanum in gadolinium have been performed in an adiabatic calorimeter over a wide temperature range, and the temperature-dependence of the ferromagnetic transition of Gd by alloying with La has been evaluated.