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16 pages, 16410 KiB

Open AccessArticle

A Tunable and Switchable Multi-Wavelength Erbium-Doped Fiber Ring Laser Enabled by Adjusting the Spectral Fringe Visibility of a Mach-Zehnder Fiber Interferometer

by Romeo Emmanuel Nuñez Gomez, Gilberto Anzueto Sánchez, Alejando Martínez Ríos, Ariel Fong González, Alfredo Olarte Paredes, Areli Marlen Salgado Delgado, Jesús Castrellón Uribe and René Salgado Delgado

Appl. Sci. 2024, 14(21), 9846; https://doi.org/10.3390/app14219846 - 28 Oct 2024

Cited by 3 | Viewed by 2449

Abstract

This paper presents a tunable, switchable multi-wavelength emission from an erbium-doped fiber ring laser, enabled by adjusting the spectral fringe visibility of a fiber interferometer filter. The filter is formed with specially designed concatenated tapered fibers to configure a Mach-Zehnder fiber interferometer (MZFI). The laser emission is highly flexible and reconfigurable, allowing for tuning between single- and dual-wavelength operation. The laser can switch sequentially from one up to six wavelengths by fixing the curvature and adjusting the polarization state. The lasing emission is generated over a stable wavelength range between 1559.59 nm and 1563.54 nm, exhibiting an optical signal-to-noise ratio (OSNR) exceeding ~35 dB. The performance of amplitude and wavelength fluctuations were evaluated, indicating an appropriate stability of ~3 dB and a shift less than 0.1 nm within a 45 min period at room temperature. A detailed comparison with the literature is given. Full article

(This article belongs to the Special Issue Recent Trends in Fiber Optic Sensor: Technology and Applications)

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17 pages, 8495 KiB

Open AccessArticle

Obtention and Characterization of GO/Epoxy and GO-GPTMS/Epoxy Nanocompounds with Different Oxidation Degrees and Ultrasound Methods

by Areli Marlen Salgado-Delgado, Elizabeth Grissel González-Mondragón, Ricardo Hernández-Pérez, René Salgado-Delgado, José Alfonso Santana-Camilo and Alfredo Olarte-Paredes

C 2023, 9(1), 28; https://doi.org/10.3390/c9010028 - 1 Mar 2023

Cited by 6 | Viewed by 3779

Abstract

This work reports the obtention of nanocompounds from epoxy resin (EP) with graphenes at three different oxidation degrees (GO1, GO2, and GO3), functionalized with 3-glycidyloxypropyl trimethoxysilane (GPTMS), and three different graphene concentrations (1%, 2%, and 3%). The aim is to improve GO compatibility in EP and obtain a nanocompound with synergistic properties. Ultrasonic bath was used to disperse the GO, a factor in the effective interaction between GO and the polymeric matrix. The nanocompounds were characterized by FTIR, SEM, and mechanical tension testing. The FTIR analysis evidenced stretching bonds created during the functionalization of graphene oxide (GO) with the silane (GPTMS); they are characteristic Si-O-Si and Si-O-C at 1000 and 1085 cm⁻¹, respectively. There was a difference between GO and GO-GPTMS nanocompounds regarding the formation of these signals. The SEM micrographs showed morphological changes when GO was added: the smooth fracture surface of EP became rougher. During tension testing, Young’s modulus (2.09 GPa) of GO2-GPTMS/epoxy nanocompounds (1% weight GO) increased by 35% while their resistance to traction (98.71 MPa) grew by 52%; both were higher than in pure EP. In conclusion, the variables studied (oxidation degrees and silanization) significantly affect the mechanical properties studied. Full article

(This article belongs to the Special Issue Advanced Carbon Based Nanomaterials)

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13 pages, 3066 KiB

Open AccessArticle

Physicochemical Characterization of Resistant Starch Type-III (RS3) Obtained by Autoclaving Malanga (Xanthosoma sagittifolium) Flour and Corn Starch

by Vicente Espinosa-Solis, Paul Baruk Zamudio-Flores, Miguel Espino-Díaz, Gilber Vela-Gutiérrez, J. Rodolfo Rendón-Villalobos, María Hernández-González, Francisco Hernández-Centeno, Hayde Yajaira López-De la Peña, René Salgado-Delgado and Adalberto Ortega-Ortega

Molecules 2021, 26(13), 4006; https://doi.org/10.3390/molecules26134006 - 30 Jun 2021

Cited by 14 | Viewed by 4647

Abstract

The feasibility of obtaining resistant starch type III (RS3) from malanga flour (Xanthosoma sagittifolium), as an unconventional source of starch, was evaluated using the hydrothermal treatment of autoclaving. The physicochemical characterization of RS3 made from malanga flour was carried out through the evaluation of the chemical composition, color attributes, and thermal properties. In addition, the contents of the total starch, available starch, resistant starch, and retrograded resistant starch were determined by in vitro enzymatic tests. A commercial corn starch sample was used to produce RS3 and utilized to compare all of the analyses. The results showed that native malanga flour behaved differently in most of the evaluations performed, compared to the commercial corn starch. These results could be explained by the presence of minor components that could interfere with the physicochemical and functional properties of the flour; however, the RS3 samples obtained from malanga flour and corn starch were similar in their thermal and morphological features, which may be related to their similarities in the content and molecular weight of amylose, in both of the samples. Furthermore, the yields for obtaining the autoclaved powders from corn starch and malanga flour were similar (≈89%), which showed that the malanga flour is an attractive raw material for obtaining RS3 with adequate yields, to be considered in the subsequent research. Full article

(This article belongs to the Special Issue Modification of Starch – from Structure, through Functionalization to Special Applications)

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19 pages, 2215 KiB

Open AccessArticle

Chitosan Films Obtained from Brachystola magna (Girard) and Its Evaluation on Quality Attributes in Sausages during Storage

by Juan Manuel Tirado-Gallegos, Paul Baruk Zamudio-Flores, Miguel Espino-Díaz, René Salgado-Delgado, Gilber Vela-Gutiérrez, Francisco Hernández-Centeno, Haydee Yajaira López-De la Peña, María Hernández-González, J Rodolfo Rendón-Villalobos and Adalberto Ortega-Ortega

Molecules 2021, 26(6), 1782; https://doi.org/10.3390/molecules26061782 - 22 Mar 2021

Cited by 8 | Viewed by 3039

Abstract

High molecular weight chitosan (≈322 kDa) was obtained from chitin isolated from Brachystola magna (Girard) to produced biodegradable films. Their physicochemical, mechanical and water vapor permeability (WVP) properties were compared against commercial chitosan films with different molecular weights. Brachystola magna chitosan films (CFBM) exhibited similar physicochemical and mechanical characteristics to those of commercial chitosans. The CFBM films presented lower WVP values (10.01 × 10⁻¹¹ g/m s Pa) than commercial chitosans films (from 16.06 × 10⁻¹¹ to 64.30 × 10⁻¹¹ g/m s Pa). Frankfurt-type sausages were covered with chitosan films and stored in refrigerated conditions (4 °C). Their quality attributes (color, weight loss, pH, moisture, texture and lipid oxidation) were evaluated at 0, 5, 10, 15 and 20 days. Sausages covered with CFMB films presented the lowest weight loss (from 1.24% to 2.38%). A higher increase in hardness (from 22.32 N to 30.63 N) was observed in sausages covered with CFMB films. Compared with other films and the control (uncovered sausages), CFMB films delay pH reduction. Moreover, this film presents the lower lipid oxidation level (0.10 malonaldehyde mg/sample kg). Thus, chitosan of B. magna could be a good alternative as packaging material for meat products with high-fat content. Full article

(This article belongs to the Special Issue Chitin and Chitosan: Derivatives and Applications II)

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