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Showing papers on "Calorimeter published in 1992"


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the burning rate of selected wood materials as determined by heat release, mass, loss and charring rates, and found that burning rate was very species dependent.
Abstract: Burning rate is a key factor in modeling fire growth and fire endurance of wood structures. This study investigated the burning rate of selected wood materials as determined by heat release, mass, loss and charring rates. Thick samples of redwood, southern pine, red oak and basswood were tested in a heat release rate calorimeter. Results on ignitability and average heat release, mass loss and charring rates are reported for a heat flux range between 15 and 55 kw m−2. In this range, burning rate increased linearly with heat flux. Burning rate was very species dependent. Heat release rate was related to mass loss by effective heat of combustion, which also increased with heat flux. Charring rate was related to mass loss rate and original wood density. Important char property data such as yield, density and contraction are reported. A simplified calculation method is proposed for calculating mass loss rate and charring rate based on heat release rate.

151 citations


Journal ArticleDOI
TL;DR: In this article, the authors used a setaram HT1500 calorimeter in step-scanning mode to measure the heat capacity of six compositions in the Na2O-FeO- Fe2O3-SiO2 system and four natural compositions (basanite, andesite, dacite and peralkaline rhyolite).
Abstract: Direct measurements of liquid heat capacity, using a Setaram HT1500 calorimeter in step-scanning mode, have been made in air on six compositions in the Na2O-FeO-Fe2O3-SiO2 system, two in the CaO-FeO-Fe2O3-SiO2 system and four of natural composition (basanite, andesite, dacite, and peralkaline rhyolite). The fitted standard deviations on our heat capacity measurements range from 0.6 to 3.6%. Step-scanning calorimetry is particularly useful when applied to iron-bearing silicate liquids because: (1) measurements are made over a small temperature interval (10K) through which the ferric-ferrous ratio of the liquid remains essentially constant during a single measurement; (2) the sample is held in equilibrium with an atmosphere that can be controlled; (3) heat capacity is measured directly and not derived from the slope of enthalpy measurements with temperature. Liquid compositions in the sodic and calcic systems were chosen because they contain large concentrations of Fe2O3 (up to 19 mol%), and their equilibrium ferric-ferrous ratios were known at every temperature of measurement. These measurement have been combined with heat capacity (Cp) data in the literature on iron-free silicate liquids to fit Cp as a function of composition. A model assuming no excess heat capacity (linear combination of partial molar heat capacities of oxide components) reproduces the liquid data within error (±2.2% on average). The derived partial molar heat capacity of the Fe2O3 component is 240.9 ±7.9 J/g.f.w.-K, with a standard error reduced by more than a factor of two from that in earlier studies. The model equation, based primarily on simple, synthetic compositions, predicts the heat capacity of the four magmatic liquids within 1.8% on average.

123 citations


Patent
10 Jul 1992
TL;DR: In this paper, a temperature gradient calorimeter and method of calculating heats of reactions is disclosed, which has a two dimensional array of reaction chambers located in a thermally conductive substrate.
Abstract: A temperature gradient calorimeter and method of calculating heats of reactions is disclosed. The calorimeter has a two dimensional array of reaction chambers located in a thermally conductive substrate. A first heat transfer medium is in thermal contact with the thermal conductive substrate and is located at one region of the array of reaction chambers. A second heat transfer medium is in thermal contact with the thermal conductive substrate and is located on the opposite side of the array from the first heat transfer medium. The first and second heat transfer mediums are at two different temperatures. That temperature difference produces a temperature gradient across the array of reaction chambers. The fluorescence intensities are measured for reactant samples located in the array of reaction chambers. By inserting the fluorescence intensity data into thermodynamic equations expressing the degree of advancement and the heat of reaction, the heat of reaction for the reaction process of the sample can be determined.

62 citations


Journal ArticleDOI
TL;DR: In this paper, an ionization signal was detected by collecting drift electrons onto an anode mesh, and a scintillation signal by collecting photoelectons in a silicon photodiode immersed in the liquid.
Abstract: In these experiments MeV's to GeV's energies were deposited in a liquid xenon test cell by an electron accelerator with kinetic energy ≤100 keV, intensity ≤10 6 e and pulse width ≤30 ns FWHM. Purification of the liquid xenon is effected by continuous circulation of boil-off gas through Oxisorb. This technique will allow operation of a liquid xenon calorimeter in a high radiation ..environment because the liquid can be continuously purified and replenished. An ionization signal was detected by collecting drift electrons onto an anode mesh, a scintillation signal by collecting photoelectons in a silicon photodiode immersed in the liquid. The energy to create an ionization electron was measured to be W = 9.76±0.70 eV. The corresponding energy to produce a 175 nm scintillation photon was found to be W s = 14.2 eV. The scintillation signal is observed to be fast ( σ t ≤14 ns). Anti-correlation of the ionization and scintillation signals was also seen. Intrinsic energy resolution σ E / E ≈ 0.07%/√( E /GeV) was determined from ionization and σ E / E ≈ 0.2%/√( E /GeV) from scintillation. Doping of xenon with up to 2% methane did not adversely affect the ionization/scintillation yields or resolutions but increased the drift velocity hence, the current signal by about 75%. The intrinsic energy resolution of a totally active xenon scintillation calorimeter will be limited by uniformity of light collection and the dead material of the calorimeter to ( σ E / E ≤ 0.5%). Detection of scintillation with a silicon (or CsI gas) photodiode permits a fast energy measurement which can be used in a first level trigger. The ionization signal will be sampled to determine the vector direction of the photon (or electron) which initiates the shower. Directional resolution σ θ = 5 mrad/√( E /GeV) achievable with this method will allow association of a detected photon to its true vertex point. At LHC ( ≈ 20 interactions per beam crossing) this calorimeter can give a Higgs mass resolution σ M / M H ≈ 0.6% via the 2γ decay mode compared to 3% for calorimeters with equal energy resolution ( σ E / E = 0.5%) but without this vertex capability. Sampling of ionization in the early part of the shower will allow discrimination against π 0 production and detect individual photons from π 0 decays thus enhancing discrimination against these important sources of hadronic background. The essential problem in measuring the shower profiles is the large amount of readout electronics needed. Cheap, current sensitive, digital VLSI electronics has already been developed and produced for the FAST RICH detector project. Studies to adapt this electronics for use in liquid xenon are underway.

57 citations


Journal ArticleDOI
TL;DR: In this article, a fully automated adiabatic heat capacity calorimeter is reported, which has been successfully operated at temperatures from 13 K to 530 K. The performance has been examined by measurements on the standard reference materials: benzoic acid (NBS SRM39i) from 15 K to 305 K and synthetic sapphire (α-Al 2 O 3 ) from 60 K to 505 K.

57 citations


Journal ArticleDOI
D H Jung, T W Kwon, D J Bae, I K Moon, Y H Jeong 
TL;DR: In this paper, the authors developed a fully automated dynamic calorimeter, which can measure the dynamic specific heat of a liquid or solid sample as a function of frequency over the range of six decades 0.01 Hz-10 kHz.
Abstract: The authors have developed a fully automated dynamic calorimeter, which can measure the dynamic specific heat of a liquid or solid sample as a function of frequency over the range of six decades 0.01 Hz-10 kHz. The shape of a solid sample can be either wire or planar. At low frequencies, the measured quantity corresponds to the usual static specific heat. With this probe, one can study the slow dynamics occurring in condensed matter systems.

50 citations


Journal ArticleDOI
TL;DR: In this article, the construction of a fully automated adiabatic calorimeter for the temperature range 50 −350 K is described. Butler et al. used a pure copper sample with a mass of 0.36 g. The measurements showed agreement within ± 1.5% of the standard literature values.

34 citations


Journal ArticleDOI
TL;DR: In this article, the thermal performance of multilayer insulation (MLI) consisting of double aluminized Mylar radiation shields and nylon net thermal spacers was evaluated using a double guarded cylindrical calorimeter and a tank-calorimeter over the temperature range 300-77 K. The degradation in effective thermal conductivity of MLI was evaluated to be 1.68 using the calorimeters.

32 citations



Journal ArticleDOI
TL;DR: In this article, the specific heat capacity of CF3CHFCF3 was measured at pressures up to 15 MPa with two flow calorimeters of high accuracy, and the comprehensive results are a basis for the determination of the enthalpy as a function of temperature and pressure.

26 citations


Journal ArticleDOI
TL;DR: In this article, a variable temperature (313 K to 353 K) titration calorimeter of high sensitivity has been constructed for complex formation and other reactions of metal cations such as hydrolysis and precipitation.

Journal ArticleDOI
TL;DR: In this article, various cables were prepared with vinyl compounds, and their fire performance tested in full-scale modified cable tray tests and in a small-scale RHR calorimeter test (cone calorimeters).

Journal ArticleDOI
I.V. Velichkov1
TL;DR: In this article, the influence of the thermal link resistances between the parts of an a.c. calorimeter is analyzed under the assumptions of constant and lumped parameters for the separate parts.

Journal ArticleDOI
01 Jan 1992-Polymer
TL;DR: In this article, an infra-red (i.r.) camera was used to observe the necking process during deformation of polycarbonate and the total balance of energy, heat and work could be measured as a function of the stretching rate.

Journal ArticleDOI
01 Jan 1992-Carbon
TL;DR: In this article, the dynamics of sulfuric acid intercalation into graphite by chemical oxidation were investigated by means of the calorimeter and potentiometer techniques, and phase composition of intermediate and end-products of the reaction was investigated by X-ray diffraction.

Journal ArticleDOI
TL;DR: In this article, the authors developed devices to perform thermal fusing of plastic optical fibers for use in the construction of sampling calorimeters with fiber optic readout, which are based on a split mold construction suitable for mass production of low loss fiber-to-fiber transitions.
Abstract: We have developed devices to perform thermal fusing of plastic optical fibers for use in the construction of sampling calorimeters with fiber optic readout. Our fusing devices are microprocessor controlled and are based on a “split mold” construction suitable for mass production of low loss fiber-to-fiber transitions. We also briefly describe our experience with the construction of large scale prototype calorimeters for CDF and SDC, where splice testing was performed as part of the calorimeter production.

Journal ArticleDOI
TL;DR: The experimental procedure described in detail enables the heat defect of water caused by electron radiation in the energy range from 1 MeV to 5 MeV with an overall uncertainty of less than 0.5% for the correction factor as mentioned in this paper.
Abstract: The experimental procedure described here in detail enables the heat defect of water caused by electron radiation in the energy range from 1 MeV to 5 MeV to be determined with an overall uncertainty of less than 0,5% for the correction factor. The principle of measurement is based on a comparison of the temperature increase caused by the radiation energy of electrons totally absorbed in water with that caused by an ohmic heating of the water. In measuring the radiant energy of the electrons, corrections are needed for backscatter of the electrons entering the water and for bremsstrahlung energy loss during electron slowing down. Precise knowledge of the heat defect is a prerequisite for the establishment of the water absorbed-dose calorimeter as a primary standard of absorbed dose to water.

Journal ArticleDOI
TL;DR: In this paper, the combined performance of two calorimeters, the high resolution uranium-scintillator prototype of the ZEUS forward calorimeter (FCAL), followed by a prototype of a coarser Zeus backing calorometer (BAC), made out of thick iron plates interleaved with planes of aluminium proportional chambers, was studied.
Abstract: We have studied the combined performance of two calorimeters, the high resolution uranium-scintillator prototype of the ZEUS forward calorimeter (FCAL), followed by a prototype of the coarser ZEUS backing calorimeter (BAC), made out of thick iron plates interleaved with planes of aluminium proportional chambers. The test results, obtained in an exposure of the calorimeter system to a hadron test beam at the CERN SPS, show that the backing calorimeter does fulfill its role of recognizing the energy leaking out of the FCAL calorimeter. The measurement of this energy is feasible, if an appropriate calibration of the BAC calorimeter is performed.

Journal ArticleDOI
TL;DR: A description of the liquid krypton calorimeter for the KEDR detector and experimental results on energy and position resolution obtained with prototypes are presented in this article, where the authors also present a detailed analysis of the Krypton detector.
Abstract: A description of the liquid krypton calorimeter for the KEDR detector and experimental results on energy and position resolution obtained with prototypes are presented.

Journal ArticleDOI
TL;DR: In this article, a power compensation scanning calorimeter and a heat flux quantitative differential thermal analyzer were used to study amorphous hydrogenated semiconducting films (a-SiC:H and a-CSiGe:H).
Abstract: Amorphous hydrogenated semiconducting films (a-SiC:H and a-CSiGe:H) were studied by means of a power compensation scanning calorimeter and a heat flux quantitative differential thermal analyzer, which work on different principles and have different cell geometry, obtaining for the same sample endothermic andexothermic traces, respectively. An analysis of the reactions has been performed and an interpretation of the antithetical results is given.

Journal ArticleDOI
TL;DR: In this article, the post-heating temperature drift curve in isoperibol heat-pulse calorimetry with isothermal shields is correctly described by an exponential function.
Abstract: The post-heating temperature drift curve in isoperibol heat-pulse calorimetry with isothermal shields is correctly described by an exponential function. The authors have implemented this analysis in an extended form in a small-sample (

Journal ArticleDOI
TL;DR: In this article, a prototype sensor for surface heat transfer measurements based on a miniature fiber Fabry-Perot (FFP) interferometer is described, which consists of a short length of single mode optical fibre (∼ 3 mm) to which low reflectivity coatings have been applied at each end.

Carl T. Kidd1
01 Sep 1992
TL;DR: The results of extensive thermal analyses of the null-point calorimeter and coaxial surface thermocouple concepts with application to measurements in aerothermal test environments are presented in this paper.
Abstract: Recent progress in techniques employed in the measurement of very high heat-transfer rates in reentry-type facilities at the Arnold Engineering Development Center (AEDC) is described. These advances include thermal analyses applied to transducer concepts used to make these measurements; improved heat-flux sensor fabrication methods, equipment, and procedures for determining the experimental time response of individual sensors; performance of absolute heat-flux calibrations at levels above 2,000 Btu/cu ft-sec (2.27 kW/cu cm); and innovative methods of performing in-situ run-to-run characterizations of heat-flux probes installed in the test facility. Graphical illustrations of the results of extensive thermal analyses of the null-point calorimeter and coaxial surface thermocouple concepts with application to measurements in aerothermal test environments are presented. Results of time response experiments and absolute calibrations of null-point calorimeters and coaxial thermocouples performed in the laboratory at intermediate to high heat-flux levels are shown. Typical AEDC high-enthalpy arc heater heat-flux data recently obtained with a Calspan-fabricated null-point probe model are included.

Journal Article
TL;DR: In this article, the heat of wetting of five Canadian species was measured with a solution calorimeter and an exponential form equation was fitted to the data and a strong relationship between the sorption energies and moisture content was found.
Abstract: The heat of wetting of five Canadian species was measured with a solution calorimeter. Differential heats of sorption and total heats of wetting were calculated and an exponential form equation was fitted to the data. A strong relationship between the sorption energies and moisture content was found.

Journal ArticleDOI
TL;DR: In this article, the electron to atom ratio interval corresponding to the martensite transition was determined by means of metallographic characterization using SEM, backed up by flow calorimeter, Differential Thermal Analysis and Differential Scanning Calorimeter for 29 polycrystalline Cuznal shape memory alloys.

Patent
13 Feb 1992
TL;DR: In this paper, a radiation beam calorimetric power measurement system for measuring the average power of a beam such as a laser beam, including a calorimeter configured to operate over a wide range of coolant flow rates and being cooled by continuously flowing coolant for absorbing light from a laserbeam to convert the laser beam energy into heat.
Abstract: A radiation beam calorimetric power measurement system for measuring the average power of a beam such as a laser beam, including a calorimeter configured to operate over a wide range of coolant flow rates and being cooled by continuously flowing coolant for absorbing light from a laser beam to convert the laser beam energy into heat. The system further includes a flow meter for measuring the coolant flow in the calorimeter and a pair of thermistors for measuring the temperature difference between the coolant inputs and outputs to the calorimeter. The system also includes a microprocessor for processing the measured coolant flow rate and the measured temperature difference to determine the average power of the laser beam.

Journal ArticleDOI
TL;DR: In this paper, the enthalpy of Au-Pb alloys was measured at 695, 871 and 1123 K by direct reaction calorimetry (drop method) with the help of a high temperature Calvet calorimeter.

Journal ArticleDOI
TL;DR: In this article, a high-resolution, high-sensitivity, automated ac calorimeter capable of heat capacity measurements on very small samples (m < 20 mg) with a temperature resolution of a few mK in the ac mode is described.
Abstract: A high‐resolution, high‐sensitivity, automated ac calorimeter capable of heat capacity measurements on very small samples (m<20 mg) with a temperature resolution of a few mK in the ac mode is described. This calorimeter also can be operated in the relaxation mode to provide absolute heat capacity values with precision and accuracy of around 2%. A microprocessor was employed to generate a stable oscillatory heating signal and to control the heater power, in order to improve the sensitivity of the measurement over other designs. A new very sensitive and miniature temperature probe (a film flake of a thermistor material), which increased measurement resolution and minimized the heat contribution of the addenda, also was used. This calorimeter was tested by measuring the heat capacity of gadolinium over its ferromagnetic phase transition. The results agree well with the literature data giving, however, substantially better resolution of the heat capacity in the critical region.

Journal ArticleDOI
TL;DR: In this paper, the results of beam tests with electrons, pions and muons in the energy range of 2 to 6 GeV are presented and compared with Monte Carlo simulations.
Abstract: Configurations of sampling calorimeters with iron, lead and uranium as absorbers have been investigated using liquid ionization chambers as active elements. As liquid tetramethylsilane has been used. Results of beam tests with electrons, pions and muons in the energy range of 2 to 6 GeV are presented and compared with Monte Carlo simulations. In particular the questions regarding which configuration can compensate and the separation of sampling from intrinsic fluctuations have been studied.

Journal ArticleDOI
TL;DR: In this paper, a combination of low-Z (Fe) and high-Z materials as absorbers allows the transformation of the electron energy distribution of the incident showers in two media with different critical energies via the filtering effect.