In this work, a continuum 2D model is proposed to study the interaction at the interface of reactive transport processes in porous media. The analysis of the segregation produced by poor reactant homogenization at the...In this work, a continuum 2D model is proposed to study the interaction at the interface of reactive transport processes in porous media. The analysis of the segregation produced by poor reactant homogenization at the poral scale is addressed by a parametric heuristic model that considers the relative gradient of the reacting species involved in the process. The micro inhomogeneities are incorporated by means of longitudinal and transversal mechanical dispersion coefficients. A two-dimensional continuous model for the bimolecular reactive transport is considered where modelling parameters are estimated numerically from experimental data. A competitive effect between segregation and dispersion is observed that is analyzed by means of numerical experiments. The two-dimensional model reproduces properly both the total mass of the product as well as its increase with the velocity of flow and the inhomogeneity of the advanced front. The methodology used is simple and fast, and the numerical results presented here indicate its effectiveness.展开更多
In this work, a numerical model is presented that describes the transfer of heat and mass inside a cylindrical regenerator of a solar adsorption refrigerator that uses the methanol/activated-carbon refrigerant pair. T...In this work, a numerical model is presented that describes the transfer of heat and mass inside a cylindrical regenerator of a solar adsorption refrigerator that uses the methanol/activated-carbon refrigerant pair. This model is based on the equations of mass conservation, energy conservation, Darcy’s law and the balance model between sorbate and sorbent given by the Dubinin-Astak- hov’s equation. On the other hand, the linear driving force (LDF) model is used to describe the rate of desorption. In the developed model, the spatial variation of methanol vapor pressure within the activated carbon bed is taken into account and, as one of the boundary conditions, the temperature is used at the external surface of the absorber measured experimentally along the day. Using the developed model, the temperature, pressure and concentration of methanol were calculated;both inside the grains of carbon and in the space between the grains, as a function of time. The algorithm was validated comparing the numerical results with the experimental data, obtaining a satisfactory concordance.展开更多
Our reconstructions of folk concepts are often influenced by the metaphysical and epistemological doctrines we are committed to.Surprisingly enough,this influence is rarely recognized in definitional debates and has b...Our reconstructions of folk concepts are often influenced by the metaphysical and epistemological doctrines we are committed to.Surprisingly enough,this influence is rarely recognized in definitional debates and has been mostly overlooked in the literature on philosophical definitions.It is frequent for philosophers to act as if only evidential support(for example,our intuitions across real and hypothetical cases)should be considered when choosing between competing reconstructions.This programmatic paper analyzes the interplay between philosophical commitments and evidence in the reconstruction of folk concepts.It also clarifies the precise manner in which metaphysical and epistemological doctrines influence philosophical definitions,why the incidence of metaphysical and epistemological doctrines is rarely recognized,and why theoretically motivated definitions should not be assimilated to the two major forms of definitions recognized in the relevant literature(descriptive and revisionary).展开更多
The Advection-Diffusion Reaction (ADR) equation appears in many problems in nature. This constitutes a general model that is useful in various scenarios, from porous media to atmospheric processes. Particularly, it is...The Advection-Diffusion Reaction (ADR) equation appears in many problems in nature. This constitutes a general model that is useful in various scenarios, from porous media to atmospheric processes. Particularly, it is used at the interface between two fluids where different types of instabilities due to surface mobility may appear. Together with the ADR equation, the Darcy-Brinkman model describes the phenomena known as fingering that appear in different contexts. The study of this type of system gains in complexity when the number of chemical species dissolved in both fluids increases. With more solutes, the increasing complexity of this phenomenon generally requires much computational power. To face the need for more computational resources, we build a solver tool based on an Alternating Direction Implicit (ADI) scheme that can be run in Central Processing Unit (CPU) and Graphic Processing Unit (GPU) architectures on any notebook. The implementation is done using the MATLAB platform to compare both versions. It is shown that using the GPU version strongly saves both resources and calculation times.展开更多
This work presents an algorithm able to simulate the heating of a solar collector throughout the day. The discussed collector is part of a solar adsorption refrigerator, and is used to regenerate the activated carbon ...This work presents an algorithm able to simulate the heating of a solar collector throughout the day. The discussed collector is part of a solar adsorption refrigerator, and is used to regenerate the activated carbon contained inside a cylindrical recipient (absorber), which is located in the focal line of a parabolic trough concentrator. The developed algorithm takes into account all the transfer mechanisms when analyzing the heat transfers taking place between the collector’s components and the environment, as well as the transfer mechanisms towards the absorber’s interior. The temperature evolution for the collector’s elements is obtained, and the model is validated by comparing the experimentally measured surface temperature of the absorber with the one determined by the algorithm. The experimental data were gathered from similar collectors in two different scenarios: Santo Domingo (Dominican Republic) and Buenos Aires (Argentina). The model is satisfactorily validated with experimental data.展开更多
文摘In this work, a continuum 2D model is proposed to study the interaction at the interface of reactive transport processes in porous media. The analysis of the segregation produced by poor reactant homogenization at the poral scale is addressed by a parametric heuristic model that considers the relative gradient of the reacting species involved in the process. The micro inhomogeneities are incorporated by means of longitudinal and transversal mechanical dispersion coefficients. A two-dimensional continuous model for the bimolecular reactive transport is considered where modelling parameters are estimated numerically from experimental data. A competitive effect between segregation and dispersion is observed that is analyzed by means of numerical experiments. The two-dimensional model reproduces properly both the total mass of the product as well as its increase with the velocity of flow and the inhomogeneity of the advanced front. The methodology used is simple and fast, and the numerical results presented here indicate its effectiveness.
文摘In this work, a numerical model is presented that describes the transfer of heat and mass inside a cylindrical regenerator of a solar adsorption refrigerator that uses the methanol/activated-carbon refrigerant pair. This model is based on the equations of mass conservation, energy conservation, Darcy’s law and the balance model between sorbate and sorbent given by the Dubinin-Astak- hov’s equation. On the other hand, the linear driving force (LDF) model is used to describe the rate of desorption. In the developed model, the spatial variation of methanol vapor pressure within the activated carbon bed is taken into account and, as one of the boundary conditions, the temperature is used at the external surface of the absorber measured experimentally along the day. Using the developed model, the temperature, pressure and concentration of methanol were calculated;both inside the grains of carbon and in the space between the grains, as a function of time. The algorithm was validated comparing the numerical results with the experimental data, obtaining a satisfactory concordance.
文摘Our reconstructions of folk concepts are often influenced by the metaphysical and epistemological doctrines we are committed to.Surprisingly enough,this influence is rarely recognized in definitional debates and has been mostly overlooked in the literature on philosophical definitions.It is frequent for philosophers to act as if only evidential support(for example,our intuitions across real and hypothetical cases)should be considered when choosing between competing reconstructions.This programmatic paper analyzes the interplay between philosophical commitments and evidence in the reconstruction of folk concepts.It also clarifies the precise manner in which metaphysical and epistemological doctrines influence philosophical definitions,why the incidence of metaphysical and epistemological doctrines is rarely recognized,and why theoretically motivated definitions should not be assimilated to the two major forms of definitions recognized in the relevant literature(descriptive and revisionary).
文摘The Advection-Diffusion Reaction (ADR) equation appears in many problems in nature. This constitutes a general model that is useful in various scenarios, from porous media to atmospheric processes. Particularly, it is used at the interface between two fluids where different types of instabilities due to surface mobility may appear. Together with the ADR equation, the Darcy-Brinkman model describes the phenomena known as fingering that appear in different contexts. The study of this type of system gains in complexity when the number of chemical species dissolved in both fluids increases. With more solutes, the increasing complexity of this phenomenon generally requires much computational power. To face the need for more computational resources, we build a solver tool based on an Alternating Direction Implicit (ADI) scheme that can be run in Central Processing Unit (CPU) and Graphic Processing Unit (GPU) architectures on any notebook. The implementation is done using the MATLAB platform to compare both versions. It is shown that using the GPU version strongly saves both resources and calculation times.
文摘This work presents an algorithm able to simulate the heating of a solar collector throughout the day. The discussed collector is part of a solar adsorption refrigerator, and is used to regenerate the activated carbon contained inside a cylindrical recipient (absorber), which is located in the focal line of a parabolic trough concentrator. The developed algorithm takes into account all the transfer mechanisms when analyzing the heat transfers taking place between the collector’s components and the environment, as well as the transfer mechanisms towards the absorber’s interior. The temperature evolution for the collector’s elements is obtained, and the model is validated by comparing the experimentally measured surface temperature of the absorber with the one determined by the algorithm. The experimental data were gathered from similar collectors in two different scenarios: Santo Domingo (Dominican Republic) and Buenos Aires (Argentina). The model is satisfactorily validated with experimental data.
