The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Marten Ternan - One of the best experts on this subject based on the ideXlab platform.
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salt impregnated carbon fibres as the Reactive Medium in a chemical heat pump the nh3 cocl2 system
Applied Thermal Engineering, 2002Co-Authors: Zine Aidoun, Marten TernanAbstract:Some of the best heat transfer results with chemical heat pumps have been obtained using chloride salts intercalated into graphite. As an alternative to intercalation, this work examined an impregnation technique that produced cobalt chloride salt crystals dispersed on carbon fibres. It is a less complex preparation procedure than the intercalation technique that has been used in other studies. Ammonia was used as both the reagent for the inter-conversion of CoCl2·2NH3 and CoCl2·6NH3 compounds and as the refrigerant. The performance of the salt–fibre material was evaluated in experiments using a bench-scale chemical heat pump reactor. The reactor was weighed continuously during the decomposition reaction, thereby providing an instantaneous measurement of the reaction rate that was independent of heat transfer measurements. The power produced by the system was measured while simultaneously monitoring temperatures, pressures, and flow rates throughout the reaction system. At a decomposition pressure of approximately 1000 kPa, power densities of 280 kW/m3 were recorded. The results obtained in this work are within the range of power densities reported previously using more complex intercalated graphite materials. This indicates that the simpler impregnation preparation method may produce materials that are suitable for practical chemical heat pumps. Consistent with other work that has been reported in the literature, degradation in the performance of the salt–fibre material was observed as a function of the cumulative time on stream. Temperature transient measurements in the reactor indicated that heat transfer was the rate-determining step for these decomposition experiments.
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Salt impregnated carbon fibres as the Reactive Medium in a chemical heat pump: the NH3–CoCl2 system
Applied Thermal Engineering, 2002Co-Authors: Zine Aidoun, Marten TernanAbstract:Some of the best heat transfer results with chemical heat pumps have been obtained using chloride salts intercalated into graphite. As an alternative to intercalation, this work examined an impregnation technique that produced cobalt chloride salt crystals dispersed on carbon fibres. It is a less complex preparation procedure than the intercalation technique that has been used in other studies. Ammonia was used as both the reagent for the inter-conversion of CoCl2·2NH3 and CoCl2·6NH3 compounds and as the refrigerant. The performance of the salt–fibre material was evaluated in experiments using a bench-scale chemical heat pump reactor. The reactor was weighed continuously during the decomposition reaction, thereby providing an instantaneous measurement of the reaction rate that was independent of heat transfer measurements. The power produced by the system was measured while simultaneously monitoring temperatures, pressures, and flow rates throughout the reaction system. At a decomposition pressure of approximately 1000 kPa, power densities of 280 kW/m3 were recorded. The results obtained in this work are within the range of power densities reported previously using more complex intercalated graphite materials. This indicates that the simpler impregnation preparation method may produce materials that are suitable for practical chemical heat pumps. Consistent with other work that has been reported in the literature, degradation in the performance of the salt–fibre material was observed as a function of the cumulative time on stream. Temperature transient measurements in the reactor indicated that heat transfer was the rate-determining step for these decomposition experiments.
S. N. Sabaev - One of the best experts on this subject based on the ideXlab platform.
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Dependence of the spin-wave resonance spectra in ferrite–garnet films on the microwave field frequency and damping parameter
Journal of Experimental and Theoretical Physics, 2016Co-Authors: A. M. Zyuzun, S. V. Bezborodov, M. A. Bakulin, V. V. Radaikin, S. N. SabaevAbstract:The factors affecting the slope of the dispersion curve of the spin-wave resonance spectrum in multilayer films are determined. It is shown that an increase in the slope of the curve for the transverse orientation of the constant magnetic field relative to the film upon an increase in frequency is due to enhancement of dynamic as well as dissipative mechanisms of spin pinning. It is found that an increase in the damping parameter increases the degree of spin pinning in the case when the pinning layer is a Reactive Medium for spin oscillations and can decrease the degree of pinning when it is a dispersive Medium. The conditions ensuring a higher degree of accuracy in determining the exchange interaction constant from the spin-wave resonance spectrum in multilayer films are determined.
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The effect of the frequency of an alternating magnetic field on the dispersion characteristics of the spin-wave resonance spectra in multilayer films
Technical Physics Letters, 2015Co-Authors: A. M. Zyuzin, M. A. Bakulin, S. V. Bezborodov, V. V. Radaikin, S. N. SabaevAbstract:It is demonstrated that the misalignment of dispersion curves for the spin-wave resonance (SWR) spectra under perpendicular and parallel (with respect to the film plane) orientations of a constant magnetic field is reduced when the frequency of an SHF field is increased. It is found that the main factor driving the increase in the curve slope under a perpendicular orientation is related to the transition of the fixation layer from the state of a Reactive Medium to the state of a dispersive one. It is shown that a dispersion curve plotted for an orientation under which the fixation layer becomes a dispersive Medium should be used in order to determine correctly the exchange interaction constant and the exchange rigidity based on the SWR spectrum.
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Spin-Wave Dispersion in Two-Layer Magnetic Films
Physics of the Solid State, 2003Co-Authors: A. M. Zyuzin, S. N. Sabaev, A. V. KulyapinAbstract:The change in spin-wave resonance spectra in multilayer magnetic films occurring under the gradual transformation of a spin-pinned layer from the Reactive Medium into a dispersive state or vice versa is studied. Spatial spin-wave dispersion associated with the spin-pinned layer is established to occur. This dispersion is most markedly pronounced in films with a mixed mechanism of spin pinning. The dispersion observed allows the so-called effect of “repulsion” of spin-wave modes to be accounted for.
Bernard Spinner - One of the best experts on this subject based on the ideXlab platform.
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a new analytical model for solid gas thermochemical reactors based on thermophysical properties of the Reactive Medium
Chemical Engineering and Processing, 1997Co-Authors: Driss Stitou, V Goetz, Bernard SpinnerAbstract:Abstract In the following study, a basis has been developed for a pseudo-permanent model, taking into account the average functioning characteristics of a solid-gas reactor during an interval of time. This model is of interest thanks to its analytical form and allows simple calculations to be made concerning the dimensioning, and thereby helps in the decision-making process. The industrial development of thermochemical reactors requires the design and construction of demonstration machines and thus calls for dimensioning models. The already existing models are based on dynamic simulation linked to the discontinuous and transient functioning mode of such processes. Hence, these dynamic models require initially arbitrary choices, which are tested successively to achieve a correct sizing of the machine. The comparison of the analytical model developed in this study with a dynamic model, and with the results of experiments, demonstrates the limits of the analytical model, as well as its reliability compared to the dynamic model. Elsewhere, the flexibility linked to its analytical form shows the scale of the field of application.
Zine Aidoun - One of the best experts on this subject based on the ideXlab platform.
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salt impregnated carbon fibres as the Reactive Medium in a chemical heat pump the nh3 cocl2 system
Applied Thermal Engineering, 2002Co-Authors: Zine Aidoun, Marten TernanAbstract:Some of the best heat transfer results with chemical heat pumps have been obtained using chloride salts intercalated into graphite. As an alternative to intercalation, this work examined an impregnation technique that produced cobalt chloride salt crystals dispersed on carbon fibres. It is a less complex preparation procedure than the intercalation technique that has been used in other studies. Ammonia was used as both the reagent for the inter-conversion of CoCl2·2NH3 and CoCl2·6NH3 compounds and as the refrigerant. The performance of the salt–fibre material was evaluated in experiments using a bench-scale chemical heat pump reactor. The reactor was weighed continuously during the decomposition reaction, thereby providing an instantaneous measurement of the reaction rate that was independent of heat transfer measurements. The power produced by the system was measured while simultaneously monitoring temperatures, pressures, and flow rates throughout the reaction system. At a decomposition pressure of approximately 1000 kPa, power densities of 280 kW/m3 were recorded. The results obtained in this work are within the range of power densities reported previously using more complex intercalated graphite materials. This indicates that the simpler impregnation preparation method may produce materials that are suitable for practical chemical heat pumps. Consistent with other work that has been reported in the literature, degradation in the performance of the salt–fibre material was observed as a function of the cumulative time on stream. Temperature transient measurements in the reactor indicated that heat transfer was the rate-determining step for these decomposition experiments.
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Salt impregnated carbon fibres as the Reactive Medium in a chemical heat pump: the NH3–CoCl2 system
Applied Thermal Engineering, 2002Co-Authors: Zine Aidoun, Marten TernanAbstract:Some of the best heat transfer results with chemical heat pumps have been obtained using chloride salts intercalated into graphite. As an alternative to intercalation, this work examined an impregnation technique that produced cobalt chloride salt crystals dispersed on carbon fibres. It is a less complex preparation procedure than the intercalation technique that has been used in other studies. Ammonia was used as both the reagent for the inter-conversion of CoCl2·2NH3 and CoCl2·6NH3 compounds and as the refrigerant. The performance of the salt–fibre material was evaluated in experiments using a bench-scale chemical heat pump reactor. The reactor was weighed continuously during the decomposition reaction, thereby providing an instantaneous measurement of the reaction rate that was independent of heat transfer measurements. The power produced by the system was measured while simultaneously monitoring temperatures, pressures, and flow rates throughout the reaction system. At a decomposition pressure of approximately 1000 kPa, power densities of 280 kW/m3 were recorded. The results obtained in this work are within the range of power densities reported previously using more complex intercalated graphite materials. This indicates that the simpler impregnation preparation method may produce materials that are suitable for practical chemical heat pumps. Consistent with other work that has been reported in the literature, degradation in the performance of the salt–fibre material was observed as a function of the cumulative time on stream. Temperature transient measurements in the reactor indicated that heat transfer was the rate-determining step for these decomposition experiments.
Driss Stitou - One of the best experts on this subject based on the ideXlab platform.
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a new analytical model for solid gas thermochemical reactors based on thermophysical properties of the Reactive Medium
Chemical Engineering and Processing, 1997Co-Authors: Driss Stitou, V Goetz, Bernard SpinnerAbstract:Abstract In the following study, a basis has been developed for a pseudo-permanent model, taking into account the average functioning characteristics of a solid-gas reactor during an interval of time. This model is of interest thanks to its analytical form and allows simple calculations to be made concerning the dimensioning, and thereby helps in the decision-making process. The industrial development of thermochemical reactors requires the design and construction of demonstration machines and thus calls for dimensioning models. The already existing models are based on dynamic simulation linked to the discontinuous and transient functioning mode of such processes. Hence, these dynamic models require initially arbitrary choices, which are tested successively to achieve a correct sizing of the machine. The comparison of the analytical model developed in this study with a dynamic model, and with the results of experiments, demonstrates the limits of the analytical model, as well as its reliability compared to the dynamic model. Elsewhere, the flexibility linked to its analytical form shows the scale of the field of application.
