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John D St George - One of the best experts on this subject based on the ideXlab platform.
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spontaneous combustion propensity of new zealand coals under Adiabatic Conditions
International Journal of Coal Geology, 2001Co-Authors: Basil Beamish, M A Barakat, John D St GeorgeAbstract:Pulverised New Zealand coal samples have been tested from an initial temperature of 40 degreesC and reacted adiabatisally in an oven with oxygen to provide a full temperature history of auto-oxidation up to the self-sustained process of combustion. This procedure produces a self-heating rate index, R-70, calculated as the ratio of the time taken to reach 70 degreesC (degreesC/h). The R-70 index is a measure of the coal's propensity to spontaneous combustion. R-70 values for New Zealand coals are much higher than any previously published results. They show a rank dependence, whereby subbituminous coals have the highest propensity to spontaneous combustion (14.91-17.23 degreesC/h). A lignite sample has an R-70 value of 7.76 degreesC/h, and high-volatile bituminous B coals have R-70 values of 0.31-2.23 degreesC/h. Samples stored for 2 years show the same rank trend. The nature of this trend is most likely a function of the internal surface area of the coal that governs the available sites for oxidation. Calculating the Suggate rank; for any New Zealand coal can be used to rare its propensity to spontaneous combustion. Resin bodies in the subbituminous coal show no propensity to spontaneous combustion. (C) 2001 Elsevier Science B.V. All rights reserved.
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Spontaneous-combustion propensity of New Zealand coals under Adiabatic Conditions
International Journal of Coal Geology, 2000Co-Authors: Basil Beamish, M A Barakat, John D St GeorgeAbstract:Pulverised New Zealand coal samples have been tested from an initial temperature of 40 degreesC and reacted adiabatisally in an oven with oxygen to provide a full temperature history of auto-oxidation up to the self-sustained process of combustion. This procedure produces a self-heating rate index, R-70, calculated as the ratio of the time taken to reach 70 degreesC (degreesC/h). The R-70 index is a measure of the coal's propensity to spontaneous combustion. R-70 values for New Zealand coals are much higher than any previously published results. They show a rank dependence, whereby subbituminous coals have the highest propensity to spontaneous combustion (14.91-17.23 degreesC/h). A lignite sample has an R-70 value of 7.76 degreesC/h, and high-volatile bituminous B coals have R-70 values of 0.31-2.23 degreesC/h. Samples stored for 2 years show the same rank trend. The nature of this trend is most likely a function of the internal surface area of the coal that governs the available sites for oxidation. Calculating the Suggate rank; for any New Zealand coal can be used to rare its propensity to spontaneous combustion. Resin bodies in the subbituminous coal show no propensity to spontaneous combustion. (C) 2001 Elsevier Science B.V. All rights reserved.
Basil Beamish - One of the best experts on this subject based on the ideXlab platform.
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spontaneous combustion propensity of new zealand coals under Adiabatic Conditions
International Journal of Coal Geology, 2001Co-Authors: Basil Beamish, M A Barakat, John D St GeorgeAbstract:Pulverised New Zealand coal samples have been tested from an initial temperature of 40 degreesC and reacted adiabatisally in an oven with oxygen to provide a full temperature history of auto-oxidation up to the self-sustained process of combustion. This procedure produces a self-heating rate index, R-70, calculated as the ratio of the time taken to reach 70 degreesC (degreesC/h). The R-70 index is a measure of the coal's propensity to spontaneous combustion. R-70 values for New Zealand coals are much higher than any previously published results. They show a rank dependence, whereby subbituminous coals have the highest propensity to spontaneous combustion (14.91-17.23 degreesC/h). A lignite sample has an R-70 value of 7.76 degreesC/h, and high-volatile bituminous B coals have R-70 values of 0.31-2.23 degreesC/h. Samples stored for 2 years show the same rank trend. The nature of this trend is most likely a function of the internal surface area of the coal that governs the available sites for oxidation. Calculating the Suggate rank; for any New Zealand coal can be used to rare its propensity to spontaneous combustion. Resin bodies in the subbituminous coal show no propensity to spontaneous combustion. (C) 2001 Elsevier Science B.V. All rights reserved.
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Spontaneous-combustion propensity of New Zealand coals under Adiabatic Conditions
International Journal of Coal Geology, 2000Co-Authors: Basil Beamish, M A Barakat, John D St GeorgeAbstract:Pulverised New Zealand coal samples have been tested from an initial temperature of 40 degreesC and reacted adiabatisally in an oven with oxygen to provide a full temperature history of auto-oxidation up to the self-sustained process of combustion. This procedure produces a self-heating rate index, R-70, calculated as the ratio of the time taken to reach 70 degreesC (degreesC/h). The R-70 index is a measure of the coal's propensity to spontaneous combustion. R-70 values for New Zealand coals are much higher than any previously published results. They show a rank dependence, whereby subbituminous coals have the highest propensity to spontaneous combustion (14.91-17.23 degreesC/h). A lignite sample has an R-70 value of 7.76 degreesC/h, and high-volatile bituminous B coals have R-70 values of 0.31-2.23 degreesC/h. Samples stored for 2 years show the same rank trend. The nature of this trend is most likely a function of the internal surface area of the coal that governs the available sites for oxidation. Calculating the Suggate rank; for any New Zealand coal can be used to rare its propensity to spontaneous combustion. Resin bodies in the subbituminous coal show no propensity to spontaneous combustion. (C) 2001 Elsevier Science B.V. All rights reserved.
Suresh V Garimella - One of the best experts on this subject based on the ideXlab platform.
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electrical impedance based void fraction measurement and flow regime identification in microchannel flows under Adiabatic Conditions
International Journal of Multiphase Flow, 2012Co-Authors: Sidharth Paranjape, Susan N Ritchey, Suresh V GarimellaAbstract:Abstract Electrical impedance of a two-phase mixture is a function of void fraction and phase distribution. The difference in the specific electrical conductance and permittivity of the two phases is exploited to measure electrical impedance for obtaining void fraction and flow regime characteristics. An electrical impedance meter is constructed for the measurement of void fraction in microchannel two-phase flow. The experiments are conducted in air–water two-phase flow under Adiabatic Conditions. A transparent acrylic test section of hydraulic diameter 780 μm is used in the experimental investigation. The impedance void meter is calibrated against the void fraction calculated using analysis of images obtained with a high-speed camera. Based on these measurements, a methodology utilizing the statistical characteristics of the void fraction signals is employed for identification of microchannel flow regimes. A self-organizing neural network is used for classification of the flow regimes.
A. Salerno - One of the best experts on this subject based on the ideXlab platform.
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Thermoelastic study of an aluminum component using an automatic correction procedure of data acquired in non-Adiabatic Conditions
Proceedings of the 2016 International Conference on Quantitative InfraRed Thermography, 2016Co-Authors: A. Gallotti, Stefano Desiderati, A. SalernoAbstract:Quantitative results in Thermoelastic Stress Analysis (TSA) are often affected by a systematic error, when the test is not performed in Adiabatic Conditions. A correction procedure can be implemented in order to recover the Adiabatic temperature, i.e. the temperature distribution that would have been present if Adiabatic Conditions had been reached. Such correction procedure however depends on the right assumption on the kind of stress distribution, e.g. linear, parabolic or cubic. The most adequate stress distribution can be chosen automatically by performing the thermoelastic test at different frequencies. This technique allowed obtaining quantitative TSA results on a helicopter aluminum component.
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Thermoelastic investigation of an aluminium helicopter component under non‐Adiabatic Conditions
Fatigue & Fracture of Engineering Materials & Structures, 2008Co-Authors: A. Gallotti, A. Salerno, S. Desiderati, G. FantoniAbstract:Thermoelastic Stress Analysis (TSA) has been used to analyze an aeronautic cross-shaped structural component, composed of several riveted parts, made of different aluminium alloys. Due to the high thermal diffusivity of aluminium, some parts of the component were not in Adiabatic Conditions during the test, causing an attenuation of the temperature peaks, linked to the stress distribution. Furthermore, the presence of a thick primer coating altered the TSA results on the component especially at high frequencies. After the removal of the primer from some parts of the surface, a correction procedure was applied to compensate for the heat diffusion, thus obtaining quantitative results, which proved to be in very good agreement with the stress values obtained by strain gauges.
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TSA-FEM Comparative Analysis of a Helicopter Component under Multiaxial Load
Strain, 2007Co-Authors: Daniele Colombo, Sara Desiderati, Marco Giglio, A. SalernoAbstract:: Thermoelastic stress analysis (TSA) is applied to a helicopter titanium tail rotor hub component with complex geometry and subjected to multiaxial loads. The frequency of the loads adopted in the TSA test was 2 Hz because of the fact that hydraulic actuators were used. As a consequence, non-Adiabatic Conditions were met in some parts of the component and a correction applied to the raw data obtained by TSA. The reliability of the corrected TSA data was checked by comparing the data with the results of a finite element model, validated previously by strain gauge measures. The good agreement between the experimental and the numerical data shows that TSA can be successfully used for structural components with complex geometry and subjected to multiaxial loads under non-Adiabatic Conditions.
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TSA‐FEM Comparative Analysis of a Helicopter Component under Multiaxial Load
Strain, 2007Co-Authors: Daniele Colombo, Marco Giglio, S. Desiderati, A. SalernoAbstract:: Thermoelastic stress analysis (TSA) is applied to a helicopter titanium tail rotor hub component with complex geometry and subjected to multiaxial loads. The frequency of the loads adopted in the TSA test was 2 Hz because of the fact that hydraulic actuators were used. As a consequence, non-Adiabatic Conditions were met in some parts of the component and a correction applied to the raw data obtained by TSA. The reliability of the corrected TSA data was checked by comparing the data with the results of a finite element model, validated previously by strain gauge measures. The good agreement between the experimental and the numerical data shows that TSA can be successfully used for structural components with complex geometry and subjected to multiaxial loads under non-Adiabatic Conditions.
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Advances in nonAdiabatic thermoelastic stress analysis of helicopter components
Materials evaluation, 2006Co-Authors: G. Fantoni, A. Salerno, S. Desiderati, L. Merletti, A. GallottiAbstract:Thermoelastic stress analysis is a powerful tool for the measurement of stress in components undergoing fatigue testing. It allows for the attainment of reliable quantitative results only in Adiabatic Conditions: that is, if heat diffusion in the component is negligible. However, in real fatigue tests on aluminum alloy components, due to the high thermal diffusivity of the material, the Adiabatic Conditions are reached only for very high frequencies of the loads applied. A correction procedure to recover the Adiabatic temperature from data obtained in nonAdiabatic Conditions has been developed and subsequently improved, allowing engineers to attain quantitative results in good accordance with classical measuring techniques, like strain gages.
M A Barakat - One of the best experts on this subject based on the ideXlab platform.
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spontaneous combustion propensity of new zealand coals under Adiabatic Conditions
International Journal of Coal Geology, 2001Co-Authors: Basil Beamish, M A Barakat, John D St GeorgeAbstract:Pulverised New Zealand coal samples have been tested from an initial temperature of 40 degreesC and reacted adiabatisally in an oven with oxygen to provide a full temperature history of auto-oxidation up to the self-sustained process of combustion. This procedure produces a self-heating rate index, R-70, calculated as the ratio of the time taken to reach 70 degreesC (degreesC/h). The R-70 index is a measure of the coal's propensity to spontaneous combustion. R-70 values for New Zealand coals are much higher than any previously published results. They show a rank dependence, whereby subbituminous coals have the highest propensity to spontaneous combustion (14.91-17.23 degreesC/h). A lignite sample has an R-70 value of 7.76 degreesC/h, and high-volatile bituminous B coals have R-70 values of 0.31-2.23 degreesC/h. Samples stored for 2 years show the same rank trend. The nature of this trend is most likely a function of the internal surface area of the coal that governs the available sites for oxidation. Calculating the Suggate rank; for any New Zealand coal can be used to rare its propensity to spontaneous combustion. Resin bodies in the subbituminous coal show no propensity to spontaneous combustion. (C) 2001 Elsevier Science B.V. All rights reserved.
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Spontaneous-combustion propensity of New Zealand coals under Adiabatic Conditions
International Journal of Coal Geology, 2000Co-Authors: Basil Beamish, M A Barakat, John D St GeorgeAbstract:Pulverised New Zealand coal samples have been tested from an initial temperature of 40 degreesC and reacted adiabatisally in an oven with oxygen to provide a full temperature history of auto-oxidation up to the self-sustained process of combustion. This procedure produces a self-heating rate index, R-70, calculated as the ratio of the time taken to reach 70 degreesC (degreesC/h). The R-70 index is a measure of the coal's propensity to spontaneous combustion. R-70 values for New Zealand coals are much higher than any previously published results. They show a rank dependence, whereby subbituminous coals have the highest propensity to spontaneous combustion (14.91-17.23 degreesC/h). A lignite sample has an R-70 value of 7.76 degreesC/h, and high-volatile bituminous B coals have R-70 values of 0.31-2.23 degreesC/h. Samples stored for 2 years show the same rank trend. The nature of this trend is most likely a function of the internal surface area of the coal that governs the available sites for oxidation. Calculating the Suggate rank; for any New Zealand coal can be used to rare its propensity to spontaneous combustion. Resin bodies in the subbituminous coal show no propensity to spontaneous combustion. (C) 2001 Elsevier Science B.V. All rights reserved.
