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a b s t r a c tThis paper presents artificial neural networks (ANN) and wavelet analysis as methods that can assist high resolution of multiple defects in close proximity in components. Without careful attention to analysis, multiple defects can be mis-interpreted as single defects and with the possibility of significantly underestimated sizes. The analysis in this work focussed on A-scan type ultrasonic signal. Amplitudes corresponding to the sizes of two defects as well as the phase shift parameter representing the distance between them were determined. The results obtained demonstrate very good correlation for sizes and distances respectively even in cases involving noisy signal data.

Abstract. An inverse artificial neural network (ANN) assessment for locating defects in bars with or without notches is presented in the paper. Postulated void defects of 1mm x 1mm were introduced into bars that were impacted with an impulse step load; the resultant elastic waves propagate impinging on the defects. The resultant transient strain field was analyzed using the finite element method. Transient strain data was collected at nodal points or sensors locations on the boundary of the bars and used to train and assess ANNs. The paper demonstrates quantitatively, the effects of features such as the design of ANN, sensing parameters such as number of data collection points, and the effect of geometric features such as notches in the bars.

The evolution of the optical absorptive effects exhibited by plasmonic nanoparticles was systematically analyzed by electronic signals modulated by a Rössler attractor system. A sol-gel approach was employed for the preparation of the studied Au nanoparticles embedded in a TiO2 thin solid film. The inclusion of the nanoparticles in an inhomogeneous biological sample integrated by human cells deposited in an ITO glass substrate was evaluated with a high level of sensitivity using an opto-electronic chaotic circuit. The optical response of the nanoparticles was determined using nanosecond laser pulses in order to guarantee the sensing performance of the system. It was shown that high-intensity irradiances at a wavelength of 532 nm could promote a change in the absorption band of the localized surface plasmon resonance associated with an increase in the nanoparticle density of the film. Moreover, it was revealed that interferometrically-controlled energy transfer mechanisms can be useful for thermo-plasmonic functions and sharp selective optical damage induced by the vectorial nature of light. Immediate applications of two-wave mixing techniques, together with chaotic effects, can be contemplated in the development of nanostructured sensors and laser-induced controlled explosions, with potential applications for biomedical photo-thermal processes.

Abstract:The main aim of this study was to characterize cooked bagasse fi bers from Agave angustifolia Haw. The fi bers were characterized using scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray Diffraction and chemical analysis. The tensile strength was also tested using fi bers with a uniform length (30 mm). The fi bers were light brown in color, with a mean diameter and length of 501 μm and 144 mm, respectively. Scanning electron microscopy images revealed elliptically shaped cells with varying lumen size. Holocellulose content was approximately 82.12 %, and total lignin content was approximately 20.69 %. Due to the crystallinity and lignin content, the fi bers proved to be thermo-stable until 220 °C.The mean values of tensile strength, Young's modulus, % strain (ε), and ultimate tensile strength were determined via mechanical tests. The results are comparable to those of other common lignocellulosic fi bers, confi rming their potential use as a reinforcing element in a polymer matrix to form a new biodegradable composite. Keywords: chemical composition, crystallinity, mechanical tests, morphology, thermal analysis Resumen: El objetivo principal de este estudio fue caracterizar las fi bras de bagazo cocido de Agave angustifolia Haw. Las fi bras fueron caracterizadas a través de microscopia electrónica de barrido, calorimetría diferencial de barrido, análisis termogravimétri-cos, difracción de rayos X y análisis químico. También se realizaron pruebas de resistencia a la tracción usando fi bras de longitud constante (30 mm). Las fi bras presentaron un color marrón claro, con diámetro medio de 501 μm y longitud media de 144 mm. Las imágenes del microscopio electrónico de barrido mostraron células de forma elíptica con diferente tamaño de lumen. El contenido de holocelulosa fue alrededor de 82.12 % y el contenido total de lignina de aproximadamente 20.69 %. La fi bra resultó ser térmicamente estable hasta 220 °C debido a la cristalinidad y el contenido de lignina. El esfuerzo de tensión, el módulo de Young, el porcentaje de deformación (ε) y el esfuerzo último de tensión fueron obtenidos de las pruebas mecánicas. Los resultados son comparables a los de otras fi bras lignocelulósicas comunes, lo cual confi rma que estas fi bras tienen potencial como refuerzo en una matriz polimérica para formar un nuevo compuesto biodegradable. Palabras clave: análisis térmico, composición química, cristalinidad, morfología, pruebas mecánicas. ETHNOBOTANY R ecently, research on plant fi bers has been increasing due to the abundance of these materials and their status as renewable resources (Joseph et al., 1999;Ghali et al., 2006;Lucena et al., 2009;Ku et al., 2011;Kestur et al., 2013). Consequently, this focus has led to further research on the specifi c characterization of individual plant fi bers such as bamboo, okra, sisal, and henequen (Mishra et al., 2004; Bé-akou et al., 2008;De Rosa et al., 2010;Liu et al., 2012;Arrakhiz et al., 2013) and studies on composite materials (Mohan...