Showing papers on "Calorimeter published in 1995"
TL;DR: This new scanning calorimeter operates differentially, is equipped with a pair of gold capillary cells and semiconductor sensors, and is able to scan up and down in temperature at user-selected rates.
174 citations
TL;DR: In this paper, a high sensitivity (1J/m2) scanning microcalorimeter that can be used at high heating rates (104°C/s) is presented.
Abstract: We introduce a high sensitivity (1J/m2) scanning microcalorimeter that can be used at high heating rates (104 °C/s). The system is designed using ultrathin SiN membranes that serve as a low thermal mass mechanical support structure for the calorimeter. Calorimetry measurements of the system are accomplished via resistive heating techniques applied to a thin film Ni heating element that also serves as a thermometer. A current pulse through the Ni heater generates heat in the sample via Joule heating. The voltage and current characteristics of the heater were measured to obtain real‐time values of the temperature and the heat delivered to the system. This technique shows potential for measuring irreversible heat of reactions for processes at interfaces and surfaces. The method is demonstrated by measuring the heat of fusion for various amounts of thermally evaporated Sn ranging from 50 to 1000 A.
162 citations
TL;DR: In this paper, a small sample adiabatic calorimeter for measuring heat capacities in the temperature range 60-350 K using the Nernst method has been constructed, and the performance of this apparatus was evaluated by heat capacity measurements on α-alumina.
Abstract: A small sample adiabatic calorimeter for measuring heat capacities in the temperature range 60–350 K using the Nernst method has been constructed. The sample cell of the calorimeter is 6 cm3 in the internal volume, equipped with a miniature platinum thermometer and surrounded by two adiabatic shields. Two sets of 6-junction chromel-copel thermocouples were mounted between the cell and the shields to indicate the temperature differences between them. The adiabatic conditions of the cell were automatically controlled by two sets of temperature controller. A mechanical pump was used to pump out the vapour of liquid nitrogen in the cryostat to solidify N2 (1), and 60 K or even lower temperature was obtained. The performance of this apparatus was evaluated by heat capacity measurements on α-alumina. The deviations of experimental results from a smoothed curve lie within ±0.2%, while the inaccuracy is within ±0.5% compared with the recommended reference data in the wole temperature range.
151 citations
TL;DR: In this article, differential scanning calorimetry (DSC) measurements have been used to determine the enthalpic relaxation of four volcanic glasses, each glass has been heated at known heating rates in the calorimeter to temperatures above the glass transition interval.
84 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 authors present the results of full-scale fires in two private motor vehicles conducted mader installed calorimeter hoods for the Channel Tunnel Safety Unit, Department of Transport.
Abstract: This paper presents the results of full-scale fires in two private motor vehicles conducted mader insturmented calorimeter hoods for the Channel Tunnel Safety Unit, Department of Transport. Measurements of heat release rate, temperatures and other parameters of fire severity are given. The results were used for the assessment of the specification and design of the shuttle wagons and in the subsequent computer modelling calculations to analyse the impact of such a fire within a shuttle wagon. The fires were well ventilated and allowed to develop fully before firefighting intervention. Of the two tests the first burned for 17 min with the gas temperature in the rig reaching 1250°C and with a peak total heat output of at least 7 1/2 MW before being extinguished. The other burned for 57 min, with gas temperatures reaching l125°C and a peak heat output of 4 1/2 MW.
63 citations
TL;DR: In this article, the temperature difference between the two cells (working and reference cells) is measured by a 20couple thermopile, which can be used for thermal equalization.
41 citations
TL;DR: A micro-combustion calorimeter suitable for samples of mass about 10 mg to 50 mg is described in this article, where the energy equivalent e° = (1809.82 ± 0.28) J·K−1.
36 citations
TL;DR: A conduction calorimeter where the sample is pressed between two identical heat fluxmeters, each having 50 chromel-constantan thermocouples, is described in this article.
Abstract: A conduction calorimeter where the sample is pressed between two identical heat fluxmeters, each having 50 chromel–constantan thermocouples, is described. The fluxmeters were built to obtain linear heat conduction and with enough rigidity to apply a controlled uniaxial stress on the sample. The method of measurement, together with the fact that the sensors themselves apply the stress to the sample, allow us to obtain absolute values of the specific heat. The specific heat of strontium titanate ferroelastic crystal is measured without stress and under an applied uniaxial stress on the face (110). The measurements were carried out while cooling the sample at a constant rate of 0.06 K/h. The data obtained at intervals of 0.02 K are compared with those obtained with an unannealed and an annealed sample, respectively.
36 citations
TL;DR: In this article, the authors used a mathematical model for the ignition of thermally thin thermoplastics to evaluate the critical heat flux, and the corresponding critical surface temperature, required for piloted ignition by using the concept that a sample ignites when the mass flux of fuel from the solid into the gas phase reaches a critical value.
34 citations
01 Oct 1995-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, a 2 m long prototype of a lead-liquid argon electromagnetic caloriemeter with accordion-shaped electrodes, conceived as a sector of the barrel calorimeter of the future ATLAS experiment at the LHC, has been tested with electron and pion beams in the energy range 10 to 287 GeV.
Abstract: A 2 m long prototype of a lead-liquid argon electromagnetic caloriemeter with accordion-shaped electrodes, conceived as a sector of the barrel calorimeter of the future ATLAS experiment at the LHC, has been tested with electron and pion beams in the energy range 10 to 287 GeV. A sampling term of 10%√E(GeV) was obtained for electrons in the rapidly range 0 < η < 1, while the constant term measured over an area of about 1 m2 is 0.69%. With a cell size of 2.7 cm the position resolution is about 4 mm√E(GeV).
TL;DR: In this paper, a dynamic differential scanning calorimeter (dynamic DSC) is used to calculate the absolute value of heat capacity by making the best of the twin-type apparatus, although the temperature resolution is a little lower than in high precision AC calorimetry.
TL;DR: In this article, the structure refinement of the room temperature X-ray powder diffraction data of ScMnO3 was carried out by Rietveld technique, based on the most probable space group P63cm.
TL;DR: In this article, the free energy, heat and entropy of mixing in a liquid Al-Sb alloy were derived by combining heat contents of the alloy with the heat and the entropy of formation of the equiatomic compound of AlSb at a reference temperature.
Abstract: The free energy, heat and entropy of mixing in a liquid Al-Sb alloy were derived by combining heat contents of the alloy with the heat and entropy of formation of the equiatomic compound of AlSb at a reference temperature. The heat contents of the alloy were measured using a drop calorimeter in a temperature range from 800 to 1450 K and in a concentration range of N sb from 0.05 to 0.95. The heat and entropy of formation of AlSb were determined respectively from the heat of solution measurements at 773 K using a twin solution calorimeter and from the heat capacity measurements in a temperature range from 4 to 300 K using an adiabatic calorimeter. The obtained thermodynamic and phase diagram data for the Al-Sb system were analyzed using a Redlich-Kister polynomial equation and the optimized parameters were derived as a function of alloy composition and temperature.
TL;DR: In this article, the heat capacities of γ-Al2O3 were measured from 50 to 700°C using an HT1000 calorimeter, and the heat of transformation from Al2O 3 to α-Al 2O3 was directly measured using a HT1500calorimeter.
01 Nov 1995-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, a very forward calorimeter is proposed based on the detection of Cherenkov light produced by relativistic shower particles in the fibers of a large number of quartz fibers embedded in a copper or iron matrix.
Abstract: Particle detection in the very forward region is one of the most crucial and at the same time one of the most difficult tasks in experiments at the future Large Hadron Collider. So far, survival of the detector in the intense radiation levels that characterize this region has been the (only) guiding principle in proposals for very forward calorimeters. In this paper, we discuss a type of detector that is not only adequate in radiation hardness, but also optimized with respect to the very specific requirements that a very forward calorimeter in an LHC experiment has to fulfill in order to be useful for the study of the physics for which it is intended. The detector consists of a large number of quartz fibers embedded in a copper (or iron) matrix and is based on the detection of Cherenkov light produced by relativistic shower particles in the fibers. We discuss the arguments for the choice of quartz, copper/iron and the fiber structure and the unique calorimeter properties that result from this choice. We present Monte Carlo simulations assessing the characteristics and the expected performance of this calorimeter.
TL;DR: In this article, a polystyrene calorimeter for dose measurement at 4-10 MeV electron accelerators is presented, where the material is used as the absorbing material and identical phantoms can be made for irradiation of other dosimeters for calibration.
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TL;DR: In this paper, the liquid heat capacities of 14 aromatic hydrocarbons were measured using a DSC calorimeter in the temperature range 100 K above the melting temperature of each hydrocarbon.
TL;DR: In this article, the performance of the High-density Projection Chamber (HPC), the barrel electromagnetic calorimeter of the DELPHI experiment, is described, where the detector adopts the time projection technique in order to obtain exceptionally fine spatial granularity.
Abstract: The performance of the High-density Projection Chamber (HPC), the barrel electromagnetic calorimeter of the DELPHI experiment, is described. The detector adopts the time projection technique in order to obtain exceptionally fine spatial granularity in the three coordinates (/spl sim/2/spl times/20 mrad/sup 2/ in /spl theta//spl times//spl phi/ with nine samplings along the shower axes), using a limited number of readout channels (18432). Among the various topics concerning the HPC construction and operation, major emphasis is given to the aspects related to the calibration in energy of the calorimeter, based mainly on the analysis of the detector response to /sup 83m/Kr decays, and to the treatment of ageing in the readout proportional counters. >
TL;DR: In this paper, a model of polymer combustion based on heat, fuel and oxygen balance in the gas was used for a description of heat release rate-time curves observed in Cone Calorimeter measurements.
Abstract: The model of polymer combustion based on heat (at two points in the polymer surface and in the gas), fuel and oxygen balance in the gas was used for a description of heat release rate-time curves observed in Cone Calorimeter measurements. It was shown that for the proper set of parameters, which were taken either from the Literature data or by a trial-and-error approach, a relatively good agreement with experimental heat release rate-time curves may be obtained. The changes of various parameters of the model leading to different limiting oxygen indices as well as to different heat release rate-time curves are discussed.
TL;DR: In this paper, the heat contents of the LaNi 5.25, Ce Ni 5.13, PrNi 4.65, and NdNi5.85 alloys were measured over the temperature range 800-1400 K using a drop calorimeter.
TL;DR: In this paper, the heat of compression and work of compression of three common pharmaceutical excipients (Avicel PH-101, anhydrous lactose, and Starch 1500) were determined using experimental instrumentation of original design.
TL;DR: In this paper, a setaram HTDSC was used to measure the specific heat difference between the liquid and crystal phases of Pd 82 Si 18 and Pd 77.5 Cu 6 Si 16.5 glass-forming alloy.
TL;DR: In this paper, the innermost part of a flow calorimeter is enclosed within a double set of aluminum shields, replacing the traditional constant temperature bath, to minimize heat loss and precisely control the flow temperature.
TL;DR: In this paper, a high-resolution heat capacity measurement has been carried out near the normalincommensurate phase transition in Rb 2 ZnCl 4 by an ac calorimeter.
Abstract: A high-resolution heat capacity measurement has been carried out near the normal-incommensurate phase transition in Rb 2 ZnCl 4 by an ac calorimeter. The obtained data have been analyzed with a renormalization-group expression which includes correction terms up to the second order. It was found that the heat capacity anomaly is described well with the three dimensional XY model; the critical exponent, the critical amplitude ratio, and the universal constant derived from the first-order correction amplitude agree well with the theoretically expected values.
TL;DR: In this article, a quasi-isothermal flow calorimeter was used to measure enthalpies at the temperatures 298.15 and 313.15 K and atmospheric pressure has been measured for (heptane + ethyl 1,1-dimethylethyl ether + ethanol) using a quasiisothermal Flow Calorimeter, and the results have been compared with the values calculated from the NRTL equation using parameters obtained from fitting the corresponding binary results.
TL;DR: In this article, a gas perfusion microcalorimetric system was developed for metabolic investigations of plant tissues under dark conditions, which consists of two heat conduction micro-calorimeters connected by gas-tight tubing.
21 Apr 1995-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, the GEANT 3.16 package and a proprietary routine describing Cherenkov photon production in optical fibres were combined to simulate the very forward regions of an LHC experiment.
Abstract: Calorimeters based on silicon core fibres embedded into an absorber have been simulated by combining the GEANT 3.16 package and a proprietary routine describing Cherenkov photon production in optical fibres. The good agreement between simulation results and experimental data allows to study, with a high degree of confidence, the design of a prototype hadronic detector and of different calorimeter configurations to cover the very forward regions of an LHC experiment.
TL;DR: In this paper, an experiment to study the β-decay of 187Re using a cryogenic μ-calorimeter is presented, where preliminary results on the 187Re β spectrum, obtained with a NTD-Ge thermistor coupled to a superconducting rhenium crystal, are included.
TL;DR: In this article, a mathematical model for the ignition of a thermally thin polymeric material in the Cone Calorimeter (autoignition mode) is presented, which contains equations for solid phase and gas phase variables, and the two phases are coupled nonlinearly.
Abstract: We establish a mathematical model for the ignition of a thermally thin polymeric material in the Cone Calorimeter (autoignition mode). The model contains equations for solid phase and gas phase variables, and the two phases are coupled nonlinearly. Of particular importance are the couplings through convective and radiative heat transfer. We use the model to evaluate the critical heat flux required for ignition and identify features of the model which require further experimental validation.