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Stagno V, Egizi F, Corticelli F, Morandi V, Valle F, Costantini G, Longo S, Capuani S. Microstructural features assessment of different waterlogged wood species by NMR diffusion validated with complementary techniques. Magn Reson Imaging 2021; 83:139-151. [PMID: 34454984 DOI: 10.1016/j.mri.2021.08.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 07/27/2021] [Accepted: 08/25/2021] [Indexed: 12/13/2022]
Abstract
Wood is a hygroscopic, multi-scale and anisotropic natural material composed of pores with different size and differently oriented. In particular, archaeologically excavated wood generally is waterlogged wood with very high moisture content (400%-800%) that need to have a rapid investigation at the microstructural level to obtain the best treatment with preservative agents. Time-dependent diffusion coefficient D(t) quantified by Pulse Field Gradient (PFG) Nuclear Magnetic Resonance (NMR) techniques provides useful information about complex porous media, such as the tortuosity (τ) describing pore connectivity and fluid transport through media, the average-pore size, the anisotropic degree (an). However, diffusion NMR is intrinsically limited since it is an indirect measure of medium microstructure and relies on inferences from models and estimation of relevant diffusion parameters. Therefore, it is necessary to validate the information obtained from NMR diffusion parameters through complementary investigations. In this work, the structures of five waterlogged wood species were studied by PFG of absorbed water. D(t) and τ of water diffusing along and perpendicular to vessels/tracheids main axes together with relaxation times and an were quantified. From these parameters, the pore sizes distribution and the wood microstructure characterization were obtained. Results among wood species were compared, validated and integrated by micro-imaging NMR (μ-MRI), environmental-scanning electron-microscope (ESEM) images, wood dry density and imbibition times measurement of all woods. The work suggests that an vs τ rather than the estimated pore size diversifies and characterize the different wood species. As a consequence diffusion-anisotropy vs tortuosity could be an alternative method to characterize and differentiate wood species of waterlogged wood when high resolution images (μ-MRI and ESEM) are not available. Moreover, the combined use of D(t) and micro-MRI expands the scale of dimensions observable by NMR covering all the interesting length scales of wood.
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Affiliation(s)
- V Stagno
- Department of Earth Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; National Research Council - Institute for Complex Systems (CNR-ISC) c/o Physics Department Sapienza University of Rome, Rome, Italy
| | - F Egizi
- National Research Council - Institute for Complex Systems (CNR-ISC) c/o Physics Department Sapienza University of Rome, Rome, Italy
| | - F Corticelli
- Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi (CNR-IMM) Bologna, P. Gobetti 101, 40129 Bologna, Italy
| | - V Morandi
- Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi (CNR-IMM) Bologna, P. Gobetti 101, 40129 Bologna, Italy
| | - F Valle
- Consiglio Nazionale delle Ricerche - Istituto per lo Studio dei Materiali Nanostrutturati (CNR-ISMN) Bologna, P. Gobetti 101, 40129 Bologna, Italy
| | - G Costantini
- National Research Council - Institute for Complex Systems (CNR-ISC) c/o Physics Department Sapienza University of Rome, Rome, Italy
| | - S Longo
- National Research Council - Institute for Complex Systems (CNR-ISC) c/o Physics Department Sapienza University of Rome, Rome, Italy; Department of Mathematical and Computational Sciences, Physics Science and Earth Sciences (MIFT), University of Messina, Messina 98166, Italy
| | - S Capuani
- National Research Council - Institute for Complex Systems (CNR-ISC) c/o Physics Department Sapienza University of Rome, Rome, Italy; Centro Fermi - Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Piazza del Viminale 1, 00184 Rome, Italy.
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El Abd A, Taman M, Zhao Y. A new method for measurement of moisture transport in porous media based on forward and backward scattering of epithermal neutrons. Appl Radiat Isot 2021; 173:109730. [PMID: 33894468 DOI: 10.1016/j.apradiso.2021.109730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 03/17/2021] [Accepted: 04/08/2021] [Indexed: 11/26/2022]
Abstract
We present a new method for determining the spatial distribution and transport of water in porous media. It is based on the detection of both forward and backward scattered neutrons from the wet regions of the samples under investigation. The experimental set-up is based on a Pu-Be neutron source and He-3 neutron detector assemblies. The results obtained showed that back scattered neutrons are more sensitive than the forward scattered neutrons to determine water content. Moreover, both forward and back scattered neutrons are more sensitive than either back or forward neutrons for determining water content. The method was used to measure moisture transport in sand columns and brick samples. Forward and backward scattered neutrons from different wet regions along the water flow path (x) are recorded as the sample absorbs water. Water saturates the regions of the samples tested near the inlet of water faster than the others. The water front positions were found to follow the square root behavior of the absorption time, and capillary penetration coefficients were determined for the samples investigated. The developed method can be used to investigate water absorption at various flow rates in porous samples of various sizes.
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Affiliation(s)
- A El Abd
- Reactor Physics Department, Nuclear Research Center, Egyptian Atomic Energy Authority, P.O. Box:13759, Inchass, Cairo, Egypt.
| | - M Taman
- Department of Structural Engineering, Faculty of Engineering, Tanta University, 31511, Tanta, Egypt
| | - Yixin Zhao
- Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources, China University of Mining and Technology (Beijing), Beijing, 100083, China; State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing, 100083, PR China; School of Energy & Mining Engineering, China University of Mining and Technology, Beijing, 100083, PR China
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Quantitative Tortuosity Measurements of Carbonate Rocks Using Pulsed Field Gradient NMR. Transp Porous Media 2019. [DOI: 10.1007/s11242-019-01341-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Li M, Vogt SJ, May EF, Johns ML. In Situ CH4–CO2 Dispersion Measurements in Rock Cores. Transp Porous Media 2019. [DOI: 10.1007/s11242-019-01278-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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