The influence of secondary processes on the porosity of volcanic rocks: A multiscale analysis using 3D X-ray microtomography

Vieira, Lucas D.; Moreira, Amanda Aleixo; Mantovani, Iara Frangiotti; Honorato, Alisson Rech; Prado, Orlando Faria; Alv, None Becker, M.R; O.C. Assis; R.R.P.; Fernandes, Celso Peres; Waichel, Breno Leitão

doi:10.1016/j.apradiso.2021.109657

Cited by 6 publications

(1 citation statement)

References 45 publications

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“…These methods utilize optical microscopy, electron microscopy, and microcomputed tomography (micro-CT). These techniques allow for obtaining images of the pore space in rocks and assessing their porosity and pore structure [40][41][42]. However, these methods also have limitations and may not always accurately represent the distribution and spatial arrangement of pores.…”

Section: Introductionmentioning

confidence: 99%

Application of Petrographic and Stereological Analyses to Describe the Pore Space of Rocks as a Standard for the Characterization of Pores in Slags and Ashes Generated after the Combustion of Municipal Waste

Godyń,

Dutka,

Tram

2023

Materials

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Slags and ashes generated in thermal waste treatment facilities require proper management. In line with the principles of the circular economy, new, more economical, and ecological possibilities for utilizing these substances are sought. These waste materials exhibit characteristics similar to rocks in many aspects. This study focuses on analyzing the similarities and differences between nine selected rocks and three samples of slags and ashes obtained from municipal waste incineration. The main research device used was a polarizing microscope, using reflected, transmitted, and fluorescent light. Additionally, low-pressure gas adsorption equipment, as well as helium and quasi-liquid pycnometers, were used for complementary analysis. The parameters analyzed mainly covered broadly defined petrographic properties of rocks and slags, with a particular emphasis on porosity, porous structure, and the spatial distribution of pores and fractures. The conducted analyses confirmed a significant similarity between slags and ashes and clastic sedimentary rocks such as sandstones and mudstones. The research results underscore the importance of petrographic microscopic studies for analyzing materials other than rocks. They also allow for exploring applications for slags and ashes in areas traditionally reserved for natural rock resources. The findings also indicate the necessity of using methods other than microscopic ones to describe the pore space of rocks. The lower measurement range of the optical microscope is limited to approximately 1 μm, covering only macropores. Other methods extend this characteristic to micro- and mesopores. Therefore, a combination of different methods is often employed to obtain a more comprehensive characterization of rock porosity.

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Section: Introductionmentioning

confidence: 99%

Application of Petrographic and Stereological Analyses to Describe the Pore Space of Rocks as a Standard for the Characterization of Pores in Slags and Ashes Generated after the Combustion of Municipal Waste

Godyń,

Dutka,

Tram

2023

Materials

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Asymptotic behaviour for convection with anomalous diffusion

Straughan,

Barletta

2024

Continuum Mech. Thermodyn.

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We investigate the fully nonlinear model for convection in a Darcy porous material where the diffusion is of anomalous type as recently proposed by Barletta. The fully nonlinear model is analysed but we allow for variable gravity or penetrative convection effects which result in spatially dependent coefficients. This spatial dependence usually requires numerical solution even in the linearized case. In this work, we demonstrate that regardless of the size of the Rayleigh number, the perturbation solution will decay exponentially in time for the superdiffusion case. In addition, we establish a similar result for convection in a bidisperse porous medium where both macro- and microporosity effects are present. Moreover, we demonstrate a similar result for thermosolutal convection.

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Sharp Instability Estimates for Bidisperse Convection with Local Thermal Non-equilibrium

Franchi,

Nibbi,

Straughan

2023

Transp Porous Med

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We analyse a theory for thermal convection in a Darcy porous material where the skeletal structure is one with macropores, but also cracks or fissures, giving rise to a series of micropores. This is thus thermal convection in a bidisperse, or double porosity, porous body. The theory allows for non-equilibrium thermal conditions in that the temperature of the solid skeleton is allowed to be different from that of the fluid in the macro- or micropores. The model does, however, allow for independent velocities and pressures of the fluid in the macro- and micropores. The threshold for linear instability is shown to be the same as that for global nonlinear stability. This is a key result because it shows that one may employ linearized theory to ensure that the key physics of the thermal convection problem has been captured. It is important to realize that this has not been shown for other theories of bidisperse media where the temperatures in the macro- and micropores may be different. An analytical expression is obtained for the critical Rayleigh number and numerical results are presented employing realistic parameters for the physical values which arise. Article Highlights A two-temperature regime for a bidisperse Darcy porous medium is proposed to study the thermal convection problem. The optimal result of coincidence between the linear instability and nonlinear stability critical thresholds is proven. Numerical analysis enhances that the scaled heat transfer coefficient between the fluid and solid and the porosity-weighted conductivity ratio stabilize the problem significantly.

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The influence of secondary processes on the porosity of volcanic rocks: A multiscale analysis using 3D X-ray microtomography

Cited by 6 publications

References 45 publications

Application of Petrographic and Stereological Analyses to Describe the Pore Space of Rocks as a Standard for the Characterization of Pores in Slags and Ashes Generated after the Combustion of Municipal Waste

Application of Petrographic and Stereological Analyses to Describe the Pore Space of Rocks as a Standard for the Characterization of Pores in Slags and Ashes Generated after the Combustion of Municipal Waste

Asymptotic behaviour for convection with anomalous diffusion

Sharp Instability Estimates for Bidisperse Convection with Local Thermal Non-equilibrium

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