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Pérez-Campos R, Monzó-Cabrera J, Fayos-Fernández J, Díaz-Morcillo A, Martínez-González A, Lozano-Guerrero AJ, Pedreño-Molina JL, García-Gambín JA. Dielectric Characterization of Fabric Aggregates around the 2.45 GHz ISM Band under Various Humidity, Density, and Temperature Conditions. Materials (Basel) 2023; 16:4428. [PMID: 37374612 DOI: 10.3390/ma16124428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/11/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023]
Abstract
Fabric permittivity is critical for the manufacturing of wearable sensors and antennas as well as predicting how fabrics interact with electromagnetic fields. Engineers should also understand how permittivity changes under different temperatures, densities, and moisture content values, or when several fabrics are mixed in aggregates, when designing future applications such as microwave dryers. The permittivity of cotton, polyester, and polyamide fabric aggregates is investigated in this paper for a wide range of compositions, moisture content levels, density values, and temperature conditions around the 2.45 GHz ISM band using a bi-reentrant resonant cavity. The obtained results show extremely comparable responses for all characteristics investigated for single and binary fabric aggregates. Permittivity always increases as temperature, density, or moisture content levels rise. Moisture content is the most influential characteristic, causing enormous variations in the permittivity of aggregates. Fitting equations are supplied for all data, with exponential functions used to accurately model variation in temperature and polynomial functions employed to precisely model density and moisture content variations with low error levels. The temperature permittivity dependence of single fabrics without the influence of air gaps is also extracted from fabric and air aggregates by using complex refractive index equations for two-phase mixtures.
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Affiliation(s)
- Rafael Pérez-Campos
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain
| | - Juan Monzó-Cabrera
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain
| | - José Fayos-Fernández
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain
| | - Alejandro Díaz-Morcillo
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain
| | - Antonio Martínez-González
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain
| | - Antonio José Lozano-Guerrero
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain
| | - Juan Luis Pedreño-Molina
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain
| | - Jose Antonio García-Gambín
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain
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Martínez-González A, Monzó-Cabrera J, Martínez-Sáez AJ, Lozano-Guerrero AJ. Minimization of measuring points for the electric field exposure map generation in indoor environments by means of Kriging interpolation and selective sampling. Environ Res 2022; 212:113577. [PMID: 35636463 DOI: 10.1016/j.envres.2022.113577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 03/15/2022] [Revised: 05/05/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
In a world with increasing systems accessing to radio spectrum, the concern for exposure to electromagnetic fields is growing and therefore it is necessary to check limits in those areas where electromagnetic sources are working. Therefore, radio and exposure maps are continuously being generated, mainly in outdoor areas, by using many interpolation techniques. In this work, Surfer software and Kriging interpolation have been used for the first time to generate an indoor exposure map. A regular measuring mesh has been generated. Elimination of Less Significant Points (ELSP) and Geometrical Elimination of Neighbors (GEN) strategies to reduce the measuring points have been presented and evaluated. Both strategies have been compared to the map generated with all the measurements by calculating the root mean square and mean absolute errors. Results indicate that ELSP method can reduce up to 70% of the mesh measuring points while producing similar exposure maps to the one generated with all the measuring points. GEN, however, produces distorted maps and much higher error indicators even for 50% of eliminated measuring points. As a conclusion, a procedure for reducing the measuring points to generate radio and exposure maps is proposed based on the ELSP method and the Kriging interpolation.
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Affiliation(s)
- A Martínez-González
- Electromagnetics and Matter Group, Universidad Politécnica de Cartagena, Campus Muralla, Cartagena, E-30202, Spain.
| | - J Monzó-Cabrera
- Electromagnetics and Matter Group, Universidad Politécnica de Cartagena, Campus Muralla, Cartagena, E-30202, Spain
| | - A J Martínez-Sáez
- Electromagnetics and Matter Group, Universidad Politécnica de Cartagena, Campus Muralla, Cartagena, E-30202, Spain
| | - A J Lozano-Guerrero
- Electromagnetics and Matter Group, Universidad Politécnica de Cartagena, Campus Muralla, Cartagena, E-30202, Spain
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Castillejo N, Martínez-Hernández GB, Lozano-Guerrero AJ, Pedreño-Molina JL, Gómez PA, Aguayo E, Artés F, Artés-Hernández F. Microwave heating modelling of a green smoothie: Effects on glucoraphanin, sulforaphane and S-methyl cysteine sulfoxide changes during storage. J Sci Food Agric 2018; 98:1863-1872. [PMID: 28885683 DOI: 10.1002/jsfa.8665] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [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: 02/27/2017] [Revised: 06/30/2017] [Accepted: 08/24/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND The heating of a green smoothie during an innovative semi-continuous microwave treatment (MW; 9 kW for 15 s) was modelled. Thermal and dielectric properties of the samples were previously determined. Furthermore, the heating effect on the main chemopreventive compounds of the smoothie and during its subsequent storage up to 30 days at 5 or 15 °C were studied. Such results were compared to conventional pasteurisation (CP; 90 °C for 45 s) while unheated fresh blended samples were used as the control. RESULTS A procedure was developed to predict the temperature distribution in samples inside the MW oven with the help of numerical tools. MW-treated samples showed the highest sulforaphane formation after 20 days, regardless of the storage temperature, while its content was two-fold reduced in CP samples. Storage of the smoothie at 5 °C is crucial for maximising the levels of the bioactive compound S-methyl cysteine sulfoxide. CONCLUSION The proposed MW treatment can be used by the food industry to obtain an excellent homogeneous heating of a green smoothie product retaining high levels of bioactive compounds during subsequent retail/domestic storage up to 1 month at 5 °C. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Noelia Castillejo
- Postharvest and Refrigeration Group, Department of Food Engineering, Universidad Politécnica de Cartagena, Cartagena, Murcia, Spain
| | - Ginés Benito Martínez-Hernández
- Postharvest and Refrigeration Group, Department of Food Engineering, Universidad Politécnica de Cartagena, Cartagena, Murcia, Spain
- Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Cartagena, Murcia, Spain
| | - Antonio José Lozano-Guerrero
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena, Cartagena, Murcia, Spain
| | - Juan Luis Pedreño-Molina
- Departamento de Tecnologías de la Información y las Comunicaciones, Universidad Politécnica de Cartagena, Cartagena, Murcia, Spain
| | - Perla A Gómez
- Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Cartagena, Murcia, Spain
| | - Encarna Aguayo
- Postharvest and Refrigeration Group, Department of Food Engineering, Universidad Politécnica de Cartagena, Cartagena, Murcia, Spain
- Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Cartagena, Murcia, Spain
| | - Francisco Artés
- Postharvest and Refrigeration Group, Department of Food Engineering, Universidad Politécnica de Cartagena, Cartagena, Murcia, Spain
- Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Cartagena, Murcia, Spain
| | - Francisco Artés-Hernández
- Postharvest and Refrigeration Group, Department of Food Engineering, Universidad Politécnica de Cartagena, Cartagena, Murcia, Spain
- Institute of Plant Biotechnology, Universidad Politécnica de Cartagena, Cartagena, Murcia, Spain
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