Determination of moisture distributions in porous building bricks by neutron radiography

El, A.; Kiсhanov, S.E.; Taman, Mohamed; Nazarov, K. M.; Козленко, Д. П.; Badawy, Wael M.

doi:10.1016/j.apradiso.2019.108970

Cited by 18 publications

(11 citation statements)

References 38 publications

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“…It means that the amount of water absorbed by sample 2 is smaller than the other samples. The water content distribution and progress of the water front inside sample 2 were determined using the procedures described in [27,29].These procedures were used to determine the water content distribution along the direction of water flow, x, and at an absorption period, t. The results are shown in Fig. 2a.…”

Section: Resultsmentioning

confidence: 99%

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Evaluation of the Efficiency of the Hydrophobic Surface Treatment for Bricks Using Neutron Imaging A. El Abd1* , M. Taman2, S.E. Kiсhanov3, E. Hamad1, К.М. Nazarov3,4 1Reactor physics department, Nuclear research Center, Egyptian Atomic Energy Authority, Egypt 2Department of Structural Engineering, Faculty of Engineering, TantaUniversity,31511,Tanta, Egypt 3Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980, Dubna, Russia 4Eurasian NationalUniversity, 010008, As

Hammad

Taman

et al. 2022

Arab Journal of Nuclear Sciences and Applications

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Capillary water absorption in building materials should be minimized because water carries chemical compounds that cause degradation. The effect of the adhesive covering on capillary water absorption in four different types of masonry bricks was investigated using neutron radiography. Only one sample revealed the creation of two layers of the coat to protect bricks against water infiltration. Water is absorbed into the gap between the two layers by capillary action. The progress of the water front between the two layers is proportional to the square root of the absorption time. The capillary penetration coefficient is 3.25 times faster than that of the identical type of sample in the bulk. Between the two layers, the amount of water absorbed is half of what is in the bulk of the sample. The coat is incapable of repelling water ingress in some samples The coat is effective on some surfaces but not recommended on others.

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Section: Resultsmentioning

confidence: 99%

“…After several days of drying in a 105°C oven, the samples were dry. The samples under examination were previously investigated in [27]. These samples were divided into two groups.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of the Efficiency of the Hydrophobic Surface Treatment for Bricks Using Neutron Imaging A. El Abd1* , M. Taman2, S.E. Kiсhanov3, E. Hamad1, К.М. Nazarov3,4 1Reactor physics department, Nuclear research Center, Egyptian Atomic Energy Authority, Egypt 2Department of Structural Engineering, Faculty of Engineering, TantaUniversity,31511,Tanta, Egypt 3Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980, Dubna, Russia 4Eurasian NationalUniversity, 010008, As

Hammad

Taman

et al. 2022

Arab Journal of Nuclear Sciences and Applications

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“…the fluid can be trapped in certain regions for prolonged periods of time which leads to the so-called subdiffusion. Recently, some experimental evidence has been given in [31] that supports this hypothesis. On the other hand, the spatial nonlocality in the porous medium equation is a consequence of the long jump phenomenon (for a physical derivation see [54]).…”

Section: Introductionmentioning

confidence: 80%

Second order scheme for self-similar solutions of a time-fractional porous medium equation on the half-line

Okrasińska-Płociniczak,

Płociniczak

2021

Preprint

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Nonlocality in time is an important property of systems in which their present state depends on the history of the whole evolution. Combined with the nonlinearity of the process it poses serious difficulties in both analytica'l and numerical treatment.We investigate a time-fractional porous medium equation that has proved to be important in many applications, notably in hydrology and material sciences. We show that the solution of both free boundary Dirichlet, Neumann, and Robin problems on the half-line satisfies a Volterra integral equation with non-Lipschitz nonlinearity. Based on this result we prove existence, uniqueness, and construct a family of numerical methods that solve these equations outperforming the usual naïve finite difference approach. Moreover, we prove the convergence of these methods and illustrate the theory with several numerical examples.

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“…For example, a subdiffusive behaviour appears when a randomly walking particle slows down in the sense that its mean-square displacement is sublinear [29,18]. A real-world example of this behaviour is water imbibition in certain porous media where complex matrix structure or chemical reactions happening there may slow down the evolution [36,35,37,8,7]. Some other places where the subdiffusion emerges is for example: turbulent flow [9], material science [30], viscoelasticity [2], cell biochemistry [44], biophysics [21], and plasma physics [5].…”

Section: Introductionmentioning

confidence: 99%

Error of the Galerkin scheme for a semilinear subdiffusion equation with time-dependent coefficients and nonsmooth data

Płociniczak¹

2022

Preprint

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We investigate the error of the (semidiscrete) Galerkin method applied to a semilinear subdiffusion equation in the presence of a nonsmooth initial data. The diffusion coefficient is allowed to depend on time. It is well-known that in such parabolic problems the spatial error increases when time decreases. The rate of this time-dependency is a function of the fractional parameter and the regularity of the initial condition. We use the energy method to find optimal bounds on the error under weak and natural assumptions on the diffusivity. First, we prove the result for the linear problem and then use the "frozen nonlinearity" technique coupled with various generalizations of Grönwall inequality to carry the result to the semilinear case. The paper ends with numerical illustrations supporting the theoretical results.

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Determination of moisture distributions in porous building bricks by neutron radiography

Cited by 18 publications

References 38 publications

Second order scheme for self-similar solutions of a time-fractional porous medium equation on the half-line

Error of the Galerkin scheme for a semilinear subdiffusion equation with time-dependent coefficients and nonsmooth data

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