Showing papers on "Calorimeter published in 2000"
Book•
28 Dec 2000
TL;DR: The history of Calorimetry can be traced back to the half a century of the early 20th century, when the first Calorimeter systems were proposed as discussed by the authors. But their performance has not yet been evaluated.
Abstract: Preface 1. Introduction: Half a Century of Calorimetry 2. The Physics of Shower Development 3. The Energy Response of Calorimeters 4. Fluctuations 5. Instrumental Aspects 6. Calibrating a Calorimeter System 7. Performance of Calorimeter Systems 8. Generic Calorimeter Studies 9. Calorimeter Systems for Experiments in Particle Physics 10. Natural Calorimeters 11. Contributions of Calorimetry to the Advancement of Science A. Notation and Abbreviations B. Properties of Materials used in Calorimeters C. Overview of Calorimeter Systems References Index
156 citations
TL;DR: In this article, the heat capacities of various liquids were determined with a high precision using differential scanning calorimetry, as implemented on a Setaram Micro DSC II calorimeter based on Calvet's differential detection of the heat flow rate in the measuring and reference vessels.
95 citations
TL;DR: In this paper, the principles and theory of operation of a magnetic calorimeter, made of a dilute concentration of paramagnetic ions in a metallic host, is discussed in relation to the use of such a device as a detector of x-rays.
Abstract: The principles and theory of operation of a magnetic calorimeter, made of a dilute concentration of paramagnetic ions in a metallic host, is discussed in relation to the use of such a device as a detector of x-rays. The response of a calorimeter to the absorption of energy depends upon size, heat capacity, temperature, magnetic field, concentration of spins and interactions among them. The conditions that optimize the performance of a calorimeter are derived. Noise sources, especially that due to thermodynamic fluctuations of the electrons in the metal, are analyzed. Measurements have been made on detectors in which Er serves as the paramagnetic ion and Au as the host metal. The measured resolution of a detector with a heat capacity of 10−12 J/K was 12 eV at 6 keV. In a detector suitable for use with hard x-rays up to 200 keV a resolution of 120 eV was obtained. Calculations indicate that the performance of both detectors can be improved by an order of magnitude. At temperatures below 50 mK, the time response of the Au : Er calorimeters to an energy deposition indicates the presence of an additional heat capacity, which we interpret as arising from the quadruple splitting of the Au nuclei in the electric field gradients introduced by the presence of the Er ions.
85 citations
TL;DR: In this paper, a scanning calorimeter was introduced for use with a single solid or liquid sample with a volume down to a few nanoliters, which was demonstrated with the melting of 52 nL of indium, using heating rates from 100 to 1000 K/s.
Abstract: We introduce a scanning calorimeter for use with a single solid or liquid sample with a volume down to a few nanoliters. Its use is demonstrated with the melting of 52 nL of indium, using heating rates from 100 to 1000 K/s. The heat of fusion was measured to within 5% of the bulk value, and the sensitivity of the measurement was ±7 μW. The heat of vaporization of water was measured in the scanning mode to be within ±23% of the bulk value by actively vaporizing water droplets from 2 to 100 nL in volume. Results within 25% were obtained for the heat of vaporization by using the calorimeter in a heat-conductive mode and measuring the passive evaporation of water. Temperature measurements over a period of 10 h had a standard deviation of 3 mK.
70 citations
TL;DR: In this article, a major discrepancy in the literature concerning the enthalpy of formation of GaN has been resolved using oxidative oxide melt solution calorimetry, where four samples of differing nitrogen contents were measured by dropping them into molten 3Na2O·4MoO3 in a calorimeter at 975 K with oxygen gas bubbling through the solvent.
Abstract: A major discrepancy in the literature concerning the enthalpy of formation of GaN has been resolved using oxidative oxide melt solution calorimetry. Four samples of differing nitrogen contents were measured by dropping them into molten 3Na2O·4MoO3 in a calorimeter at 975 K with oxygen gas bubbling through the solvent. The samples were characterized by X-ray diffraction, chemical analysis, transmission electron microscopy, particle size analysis, and BET measurements. The enthalpy of drop solution (kJ/g) varied approximately linearly with nitrogen content. Extrapolated to stoichiometric GaN, the data yield a value of −156.8 ± 16.0 kJ/mol for the standard enthalpy of formation from the elements at 298 K. The relatively large error reflects the deviation of individual points from the straight line rather than uncertainties in each set of data for a given sample. This new directly measured enthalpy of formation is in excellent agreement with that obtained from the temperature dependence of the equilibrium pre...
64 citations
TL;DR: In this article, it was shown that traditional procedure of measurement of heat capacity by the triple heat bridge method causes systematic error tied with a noncompensated asymmetry of a device.
60 citations
01 Jan 2000
TL;DR: A semi-empirical model to represent compressor performance has been investigated in this article, which is based on the concept of volumetric efficiency and assumes a polytropic compression process.
Abstract: Mass flow rate and power calorimeter test data for domestic refrigerator/freezer fully hermetic compressors have been collected on compressors from three manufacturers. The calorimeter test data were taken by 10 different organizations. These test data are commonly correlated with 10-coefficient polynomials (using the method presented in ARI Standard 540-91) as a function of the saturated evaporator and condenser temperatures. In general, these polynomial representations accurately represent the experimental data but do not necessarily provide reliable interpolations or extrapolations for conditions not represented in the compressor calorimeter tests. A semi-empirical model to represent compressor performance has been investigated. The model is based on the concept of volumetric efficiency and assumes a polytropic compression process. The model has five parameters that must be determined by fitting experimental data. Four or more measurements of refrigerant flow rate and compressor power were found to be sufficient to determine the model parameters, thereby allowing the generation of accurate compressor maps with the model. The model has been found to extrapolate within 5% error with condensing and evaporating temperatures that extend beyond the measured data by 10 °C (18°F). A small set of available data for suction temperatures other than 32.2°C (90°F) were investigated. The results indicate that the model can accurately model the effect of changes in the suction temperature.
60 citations
TL;DR: In this paper, a small sample size automated adiabatic calorimeter for measuring heat capacities in the temperature range of 60-360 K has been constructed, which was made of thin-walled gold-plated copper with an internal volume of 6 cm 3.
50 citations
Patent•
15 Jun 2000
TL;DR: In this paper, a system and method for an improved calorimeter for determining thermodynamic properties of biological and chemical reactions is presented. But the system can measure samples 1000 times smaller than conventional systems and the binding constants are derived from a single experiment using a single device.
Abstract: A system and method for an improved calorimeter for determining thermodynamic properties of biological and chemical reactions. The system can measure samples 1000 times smaller than conventional systems. The heat capacity and the enthalpy of chemical and biological systems are measured in a single experiment using a single device. Binding constants are derived from a single experiment. Microcalorimeter devices are manufactured in a microelectronics fabrication facility and comprise a thin amorphous membrane anchored to a frame. Thermometers and heaters are placed on one side of a thermal conduction layer mounted on the central portion of the membrane. High volume arrays are manufactured to facilitate large-scale operations, such as high-throughput pharmaceutical drug screening. An environmental chamber is vacated and humidified. A first sample is placed on the membrane of a first microcalorimeter. A second sample is placed on the membrane of a second microcalorimeter. The samples are combined by sandwiching the two microcalorimeters together.
47 citations
TL;DR: In this paper, the authors used differential scanning calorimetry to measure the heat capacity of diamond-like carbon (DLC) film prepared by a plasma immersion ion processing method.
Abstract: We have used differential scanning calorimetry to measure the heat capacity of diamond-like carbon (DLC) film prepared by a plasma immersion ion processing method. The same calorimeter was used to measure the heat capacity of single crystal natural diamond and of high purity graphite. The amount of atomic hydrogen trapped in the DLC films was determined by elastic-recoil-detection spectrometry. The present data and literature values were used to deduce an expression for the specific heat that factors out the contribution from the sp3/sp2 bonding and from the atomic hydrogen trapped in the carbon. The data shows that the hydrogen contribution to the specific heat of carbon is independent of the sp3/sp2 bonding and amounts to about 0.63kB per hydrogen atom. We propose a simple method to determine the sp3/sp2 bonding ratio in hydrogenated DLC films based on measuring the specific heat and the hydrogen content of the sample.
45 citations
TL;DR: In this paper, the physics phenomena at the base of cascading processes in matter and the basic principles of calorimeters operation are reviewed at the light of data obtained from running experiments or from sets of dedicated measurements and the constraints from physics requirements.
Abstract: Calorimetry plays a crucial role in modern experimental physics. Calorimeters are essential tools to extract physics in accelerator and non-accelerator experiments. The physics phenomena at the base of cascading processes in matter and the basic principles of calorimeters operation are reviewed at the light of data obtained from running experiments or from sets of dedicated measurements and the constraints from physics requirements. From this understanding comes the possibility of building powerful calorimetric systems with the optimal performances required by future experiments at high-energy and ultrahigh-energy regimes.
TL;DR: In this article, a differential scanning calorimeter was calibrated by the Joule effect and by measuring the temperature of fusion of several pure (99.999%) metals, and the results demonstrate that thiscalorimeter is capable of producing data of enthalpies of fusion with an uncertainty of 1.5, temperatures of fusion between 0.1 and 0.2
TL;DR: Stuckless et al. as mentioned in this paper used a 9 μm pyroelectric polymer ribbon to make a gentle mechanical/thermal contact to the back of the single-crystal sample during measurement.
Abstract: In microcalorimetry for measuring heats of adsorption on clean single-crystal surfaces, a pulse of gas from a molecular beam adsorbs on an ultrathin single crystal's surface, causing a measurable transient heat input and temperature rise. One new and sensitive method of heat detection uses a 9 μm pyroelectric polymer ribbon, which is mechanically driven to make a gentle mechanical/thermal contact to the back of the single-crystal sample during measurement (J.T. Stuckless, N.A. Frei, C.T. Campbell, A novel single-crystal adsorption calorimeter and additions for determining metal adsorption and adhesion energies, Rev. Sci. Instr. 69, 1998, 2427–2438). Here we describe simulations of the signal pulse shape and an analysis of absolute signal intensities, based on system parameters such as the detector pyroelectric coefficient and thermal conductivities of the detector and sample, in order to understand heat collection efficiency in this and related calorimetric techniques.
TL;DR: In this article, a Tian−Calvet batch calorimeter was used to measure the saturated liquid heat capacity with an approximate uncertainty of ± 0.5% and cover a temperature range between 310 K and 420 K.
Abstract: Heat capacities for 1,2-dimethoxybenzene, 2,5,8,11-triethylene glycol dimethyl ether, N-ethyl-2-pyrrolidone, isopentyl acetate, 2-ethylhexanal, toluene, 1-phenylethanol, propyl acetate, octyl acetate, dimethyl sulfoxide, diethyl phthalate, and diethyl carbonate were measured with the “three-step” method using a Tian−Calvet batch calorimeter. The measurements of saturated liquid heat capacity have an approximate uncertainty of ±0.5% and cover a temperature range between 310 K and 420 K. Furthermore, the experimental results were compared with three group contribution methods for liquid heat capacities.
06 Feb 2000
TL;DR: In this article, an improved calorimeter which excludes winding loss and measures core loss alone is presented, which is used to measure core loss for distributed-air-gap magnetic materials.
Abstract: Accurate measurements of core loss for distributed-air-gap magnetic materials have traditionally been very difficult to obtain. Wattmeter measurements are affected by very small phase and time-delay measurement errors, while traditional calorimeters measure the sum of excitation winding loss and core loss. This paper presents an improved calorimeter which excludes winding loss and measures core loss alone.
TL;DR: Initial operation at the National Physical Laboratory in x-ray and electron beams from the NPL linear accelerator shows that the new calorimeter is capable of measurements of 1 Gy at 2 Gy min(-1) with a random uncertainty of +/-0.3% (1 standard deviation).
Abstract: This paper describes the development of a robust and portable calorimeter for use in clinical electron and photon beams. Although intended for therapy-level dosimetry, the new calorimeter can also be used for high-dose measurements at industrial facilities. The system consists of a front end (the calorimeter itself), means for thermal isolation and temperature control, and a measurement system based on thermistors in a dc Wheatstone bridge. It was found from investigation that the heat transfer between components was significant. The restrictions on the design placed by the requirement for portability led to higher heat transfer than was desirable. Much effort was put into thermodynamic modelling of the system and determining the heat transfer coefficients. Effort was also focused on the development of a temperature control system sensitive enough to allow measurements of temperature rises of the order of 1 mK. The control system responds to the calorimeter, phantom and air temperatures and maintains the temperature of the calorimeter to within ±0.2 mK over several hours. Initial operation at the National Physical Laboratory (NPL) in x-ray and electron beams from the NPL linear accelerator shows that the system is capable of measurements of 1 Gy at 2 Gy min-1 with a random uncertainty of ±0.3% (1 standard deviation). Operation in 60Co at a doserate of 1 Gy min-1 has also been achieved with a similar uncertainty. It is intended to test the calorimeter `in the field' during 2000.
TL;DR: The modulated adiabatic scanning calorimeter (MASC) described in this paper is designed to work in both the time domain (adiabatic-like step-scanning) and in the frequency domain (modulated temperature/power scanning) operational modes.
TL;DR: In this paper, the design and properties of a double twin heat conduction microcalorimeter are described and the cross-talk between the calorimeters can be made low; they measured < 0.1% of the signal generated in one calorimeter in the other.
Patent•
24 Oct 2000
TL;DR: In this article, a portable calorimeter, which can be worn by the individual, includes a cardiac rate monitor that measures the cardiac rate of the individual and communicates data representative of the individuals' cardiac rate to the processor, which then determines the metabolic rate of an individual based on relationship data obtained from the respiratory-based Calorimeter.
Abstract: A calorimeter configured to determine a metabolic rate of an individual based on measurements of the individual's respiration. The calorimeter includes an inlet, a flow sensor, a mixing chamber, a gas sensor, and a calibrator. Each of these elements is located along a flow path through the calorimeter. The calibrator of the calorimeter includes a fan that is configured to force calibration gases, such as room air, through or past the gas sensor. A cardiac rate monitor is associated with a processor of the calorimeter. The processor is configured to substantially simultaneously determine and establish a relationship between the cardiac rate of the individual and the measured respiratory parameters or the metabolic rate of the individual. Data representative of this relationship may be communicated to a processor or memory of a portable calorimeter to be subsequently used by the individual. The portable calorimeter, which can be worn by the individual, includes a cardiac rate monitor that measures the cardiac rate of the individual and communicates data representative of the individual's cardiac rate to the processor, which then determines the metabolic rate of the individual based on relationship data obtained from the respiratory-based calorimeter. Methods of calibrating and using the calorimeters are also disclosed.
11 May 2000-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, the main features of the calorimeter calibration procedure are also reported, as well as the first physics signals detected by the Calorimeter in recent data taken during the commissioning of the installed HERA-B detector are described.
Abstract: The electromagnetic calorimeter of the HERA-B experiment is described. The main features of the calorimeter calibration procedure are also reported. Finally the first physics signals detected by the calorimeter in recent data taken during the commissioning of the installed HERA-B detector are described.
TL;DR: In this article, the authors developed a calorimeter that gives a qualitative picture of the specific heat of a sample under high pressure up to ≈10 GPa. The principle of AC-calorimetry was adapted to the conditions in a high pressure clamp.
TL;DR: In this paper, a procedure was developed to calibrate the Calorimetry Sciences Corporation Models 5100 and 6100 Nano-DSCs to measure more precisely volumetric heat capacities of liquids and solutions.
07 Apr 2000-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, progress made so far at NASA Goddard Space Flight Center towards the development of arrays of X-ray microcalorimeters as candidates for the high-resolution Xray spectrometer on the Constellation-X mission is reported.
Abstract: We report on progress made so far at NASA Goddard Space Flight Center towards the development of arrays of X-ray microcalorimeters as candidates for the high-resolution X-ray spectrometer on the Constellation-X mission. In the design concept presently under consideration, the microcalorimeter consists of (i) a Bi/Cu multilayer absorber for stopping and thermalizing the incident X-rays, (ii) an e-beam evaporated Mo/Au proximity bilayer with sputtered Nb leads for sensing the resultant temperature rise, and (iii) a silicon nitride membrane to provide a weak thermal link to the sink temperature so that the calorimeter can return to its equilibrium temperature. Fabrication details and preliminary results are reported.
Patent•
23 Aug 2000
TL;DR: A power compensation differential scanning calorimeter that uses one absolute temperature measurement, two differential temperature measurements, a differential power measurement, and a five-term heat flow equation to measure the sample heat flow is described in this paper.
Abstract: A power compensation differential scanning calorimeter that uses one absolute temperature measurement, two differential temperature measurements, a differential power measurement, and a five-term heat flow equation to measure the sample heat flow. The calorimeter is calibrated by running two sequential calibration experiments. In a preferred embodiment, the first calibration experiment uses empty sample and reference pans, and the second calibration experiment uses sapphire specimens in the sample and reference holders. In an alternate embodiment, sapphire calibration specimens are used in both the first and second calibration experiments.
TL;DR: In this article, the low-temperature heat capacities of trifluoroacetamide were precisely determined with a small sample precision automated adiabatic calorimeter over the temperature range from 78 to 404 K.
TL;DR: In this article, the Mettler-Toledo 820 ADSC™ temperature-modulated differential scanning calorimeter (TMDSC) was used to calculate heat capacity.
Abstract: The determination of heat capacity data with sawtooth-type, temperature-modulated differential scanning calorimetry is analyzed using the Mettler-Toledo 820 ADSC™temperature-modulated differential scanning calorimeter (TMDSC). Heat capacities were calculated via the amplitudes of the first and higher harmonics of the Fourier series of the heat flow and heating rates. At modulation periods lower than about 150 s, the heat capacity deviates increasingly to smaller values and requires a calibration as function of frequency. An earlier derived correction function which was applied to the sample temperature-controlled power compensation calorimeter enables an empirical correction down to modulation periods of about 20 s. The correction function is determined by analysis of the higher harmonics of the Fourier transform from a single measurement of sufficient long modulation period. The correction function reveals that the time constant of the instrument is about 5 s rad−1 when a standard aluminum pan is used. The influence of pan type and sample mass on the time constant is determined, the correction for the asymmetry of the system is described, and the effect of smoothing of the modulated heat flow rate data is discussed.
TL;DR: In this paper, the enthalpy of solution of aqueous sodium chloride, obtained with an adiabatic solution calorimeter, is compared to a previous equation of state for NaCl(aq).
TL;DR: The aim of this investigation was to determine and evaluate the thermodynamic properties, i.e. heat, work, and internal energy change, of the compaction process by developing a 'Compaction Calorimeter', and to address the thermodynamics evaluation of the tablet sub-processes of unloading and ejection.
TL;DR: In this paper, the authors measured the heat capacity of liquid n-tridecane at temperatures from 313.15 to 373.15 K and at pressures up to 100 MPa using a calorimetric device based on a Calvet calorimeter (Setaram C80).
Abstract: Isobaric heat capacities of liquid n-tridecane were measured at temperatures from 313.15 to 373.15 K and at pressures up to 100 MPa using a calorimetric device based on a Calvet calorimeter (Setaram C80). These experimental data combined with the additional knowledge of density data were used to calculate the following properties at pressures up to 100 MPa: isochoric heat capacity, isentropic compressibility and ultrasound velocity.
TL;DR: In this article, a method for measuring changes of enthalpy to discriminate the contribution due to the latent heat from that due to temperature dependence of the specific heat near the transition point is presented.