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Medina A, Aguilar C, Sandoval LJ, Borjas SE, Pacheco S, Bernal JL. SEM and EDS Analysis of Ti-13Ta-1Cu Alloy Obtained by Mechanical Alloying. Microsc Microanal 2023; 29:811-812. [PMID: 37613439 DOI: 10.1093/micmic/ozad067.403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- A Medina
- Instituto de Investigación en Metalurgia y Materiales. Universidad Michoacana de San Nicolas de Hidalgo. Morelia, Michoacán, México
| | - C Aguilar
- Departamento de Metalurgia. Universidad Federico Santa María, Valparaíso Chile
| | - L J Sandoval
- Instituto de Investigación en Metalurgia y Materiales. Universidad Michoacana de San Nicolas de Hidalgo. Morelia, Michoacán, México
| | - S E Borjas
- Instituto de Físico Matemáticas. Universidad Michoacana de San Nicolas de Hidalgo. Morelia, Michoacán, México
| | - S Pacheco
- Departamento de Ingeniería Mecánica. Universidad Autónoma del Estado de Hidalgo, Ciudad Sahagún, Hidalgo.México
| | - J L Bernal
- Departamento de Ingeniería Mecánica, Instituto Tecnológico de Orizaba, Veracruz México
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Abuhani WA, Dasgupta-Schubert N, Villaseñor LM, García Avila D, Suárez L, Johnston C, Borjas SE, Alexander SA, Landsberger S, Suárez MC. Naturally occurring heavy radioactive elements in the geothermal microcosm of the Los Azufres (Mexico) volcanic complex. J Environ Radioact 2015; 139:33-42. [PMID: 25464039 DOI: 10.1016/j.jenvrad.2014.08.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 08/21/2014] [Accepted: 08/30/2014] [Indexed: 06/04/2023]
Abstract
The Los Azufres geothermal complex of central Mexico is characterized by fumaroles and boiling hot-springs. The fumaroles form habitats for extremophilic mosses and ferns. Physico-chemical measurements of two relatively pristine fumarolic microcosms point to their resemblance with the paleo-environment of earth during the Ordovician and Devonian periods. These geothermal habitats were analysed for the distribution of elemental mass fractions in the rhizospheric soil (RS), the native volcanic substrate (VS) and the sediments (S), using the new high-sensitivity technique of polarized x-ray energy dispersive fluorescence spectrometry (PEDXRF) as well as instrumental neutron activation analysis (INAA) for selected elements. This work presents the results for the naturally occurring heavy radioactive elements (NOHRE) Bi, Th and U but principally the latter two. For the RS, the density was found to be the least and the total organic matter content the most. Bi was found to be negligibly present in all substrate types. The average Th and U mass fractions in the RS were higher than in the VS and about equal to their average mass fractions in the S. The VS mass fraction of Th was higher, and of U lower, than the mass fractions in the earth's crust. In fact for the fumaroles of one site, the average RS mass fractions of these elements were higher than the averaged values for S (without considering the statistical dispersion). The immobilization of the NOHRE in the RS is brought about by the bio-geochemical processes specific to these extremophiles. Its effectiveness is such that despite the small masses of these plants, it compares with, or may sometimes exceed, the immobilization of the NOHRE in the S by the abiotic and aggressive chemical action of the hot-springs. These results indicate that the fumarolic plants are able to transform the volcanic substrate to soil and to affect the NOHRE mass fractions even though these elements are not plant nutrients. Mirrored back to the paleo times when such plant types were ubiquitous, it would mean that the first plants contributed significantly to pedogenesis and the biogeochemical recycling of even the heaviest and radioactive elements. Such plants may potentially be useful for the phytostabilisation of soil moderately contaminated by the NOHRE. Furthermore where applicable, geochronology may require taking into account the influence of the early plants on the NOHRE distributions.
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Affiliation(s)
- W A Abuhani
- Inst. Físicas y Matemáticas, Universidad Michoacana (UMSNH), Morelia, Michoacán, Mexico.
| | - N Dasgupta-Schubert
- Inst. Invest. Químico Biológicas, Universidad Michoacana (UMSNH), Morelia, Michoacán, Mexico.
| | - L M Villaseñor
- Inst. Físicas y Matemáticas, Universidad Michoacana (UMSNH), Morelia, Michoacán, Mexico.
| | - D García Avila
- Fac. Biología, Universidad Michoacana (UMSNH), Morelia, Michoacán, Mexico.
| | - L Suárez
- Fac. Biología, Universidad Michoacana (UMSNH), Morelia, Michoacán, Mexico.
| | - C Johnston
- Dept. of Physics, Southwestern University (SU), Georgetown, TX, USA.
| | - S E Borjas
- Inst. Físicas y Matemáticas, Universidad Michoacana (UMSNH), Morelia, Michoacán, Mexico.
| | - S A Alexander
- Dept. of Physics, Southwestern University (SU), Georgetown, TX, USA.
| | - S Landsberger
- Nuclear Engineering Teaching Lab., University of Texas (UT), Austin, TX, USA.
| | - M C Suárez
- Fac. Ciencias Físico-Matemáticas, Universidad Michoacana (UMSNH), Morelia, Michoacán, Mexico.
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