The 2D Continuous Wavelet Transform: Applications in Fringe Pattern Processing for Optical Measurement Techniques

Optical metrology and interferometry are widely known disciplines that study and develop techniques to measure physical quantities such as dimensions, force, temperature, stress, etc. A key part of these disciplines is the processing of interferograms, also called fringe patterns. Owing that this kind of images contains the information of interest in a codified form, processing them is of main relevance and has been a widely studied topic for many years. Several mathematical tools have been used to analyze fringe patterns, from the classic Fourier analysis to regularization methods. Some methods based on wavelet theory have been proposed for this purpose in the last years and have evidenced virtues to consider them as a good alternative for fringe pattern analysis. In this chapter, we resume the theoretical basis of fringe pattern image formation and processing, and some of the most relevant applications of the 2D continuous wavelet transform (CWT) in fringe pattern analysis

Alternative system to measure hydrogen content in molten aluminium using an electrochemical sensor

The most reliable techniques for the direct measurement of hydrogen content in liquid aluminium are based on Sievert’s law or use electrochemical probes introduced directly in liquid aluminium. The main drawback of these methods is the high cost of the equipment. An alternative apparatus has been developed and tested. This equipment combines a widely used and much cheaper hydrogen electrochemical sensor with the procedure already patented and commonly used by gas recirculation techniques. The device has been constructed and calibrated using gaseous mixtures of known hydrogen content. For validation, the results obtained with this apparatus have been compared with hydrogen content measurements in liquid aluminium using the commercial Alscan equipment in an industrial facility. Experimental results suggest that the apparatus proposed in this work is capable of detecting hydrogen content in liquid aluminium obtaining measurements that are in a good agreement with those obtained using the commercial Alscan equipment. On the other hand, results also suggest that it is important to take into account the operating atmospheric pressure to correct the readings obtained from Alscan when operating at atmospheric pressure levels far from 1 atm

LA TECNOLOGÍA MEMS COMO AUXILIAR EN EL POSICIONAMIENTO GPS A BAJO COSTO

Hoy en día la navegación por GPS es una herramienta cotidiana muy útil para la humanidad, gracias a esta tecnología las personas pueden desplazarse por lugares en los cuales no han estado antes con cierto grado de precisión. La ubicación de un punto sobre la superficie terrestre se hace por medio de un satélite transmisor y un receptor que se ubica por medio del principio de Triangulación. Los Sistemas-Micro-Electro-Mecánicos o MEMS, son una tecnología que, en su forma más general puede ser definida como elementos electro-mecánicos miniaturizados que se realizan con técnicas de micro -fabricación.Las unidades de medición inercial o IMU, son dispositivos que miden aceleración y orientación, que implementados con algún procesador o sistema de cómputos permiten crear un sistema de navegación inercial o INS. El enfoque de esta investigación es crear un sistema de bajo costo que permita fusionar los datos provenientes de los sistemas IMU/GPS mediante un filtro Kalman, esto con la finalidad de aprovechar las características propias de cada sistema y mejorar la precisión del posicionamiento por GPS. Con el uso de este sistema mediante sensores comerciales de bajo costo se hace posible mejorar la precisión del posicionamiento GPS con hasta un 3.03%

Analytical Proposals for the Interpretation of the Works Introduction Theme and Variations by Gioachino Rossini and Dance Preludes by Witold Lutoslawski

La presente investigación se plantea como un análisis académico estructural profundo que abarca aspectos estéticos, filosóficos y musicales, centrándose específicamente en las composiciones de dos destacados compositores: Gioachino Rossini y Witold Lutoslawski. Estos músicos representan periodos contrastantes en la historia de la música, lo que añade una riqueza significativa al análisis. El enfoque de esta investigación busca ir más allá de la mera apreciación superficial de las obras, procurando una comprensión más profunda mediante el análisis detallado de la forma y la fragmentación de los elementos expresivos presentes en sus composiciones. La culminación de este análisis se refleja en la apropiación del criterio estético-musical de los compositores, convirtiéndose en el fundamento para un acercamiento crítico que enriquece la interpretación musical. El proceso resulta en la construcción de un pensamiento musical contemporáneo interpretativo, respaldado por la asimilación de preceptos estilísticos discernidos durante la investigación. Además, se propone una perspectiva analítica tanto para los instrumentistas como para el público en general. El propósito es proporcionar un marco conceptual que facilite la profundización en conocimientos y criterios musicales, ofreciendo una herramienta valiosa para la apreciación musical desde diversos ángulos. Este artículo no solo pretende ser un análisis exhaustivo, sino también se presenta como un punto de partida para una discusión más amplia sobre el papel crucial de la interpretación musical en la apreciación estética y filosófica de las obras seleccionadas. Aspira a proporcionar un enfoque comprensivo que abarque aspectos técnicos, estilísticos y emocionales, brindando así una experiencia musical enriquecedora y completa para aquellos que se sumergen en estas obras.The present research is conceived as a profound structural academic analysis that encompasses aesthetic, philosophical, and musical aspects, specifically focusing on the compositions of two prominent composers: Gioachino Rossini and Witold Lutoslawski. These musicians represent contrasting periods in the history of music, adding significant richness to the analysis. The focus of this research aims to go beyond mere superficial appreciation of the works, seeking a deeper understanding through detailed analysis of the form and breakdown of expressive elements present in their compositions. The culmination of this analysis is reflected in the appropriation of the composers' aesthetic-musical criteria, becoming the foundation for a critical approach that enriches musical interpretation. The process results in the construction of a contemporary interpretative musical thought, supported by the assimilation of stylistic precepts discerned during the research. Furthermore, an analytical perspective is proposed for both instrumentalists and the general public. The purpose is to provide a conceptual framework that facilitates deepening of knowledge and musical criteria, offering a valuable tool for musical appreciation from various angles. This article not only aims to be a comprehensive analysis but also presents itself as a starting point for a broader discussion on the crucial role of musical interpretation in the aesthetic and philosophical appreciation of the selected works. It aspires to provide a comprehensive approach that encompasses technical, stylistic, and emotional aspects, thus offering an enriching and complete musical experience for those immersing themselves in these compositions

Reforestation and conservation of native trees in the Municipality of San Rafael Municipality of San Sebastián Magdalena

El objetivo de esta investigación fue dar a conocer el estado actual de la deforestación, como una de las acciones del hombre en el uso indiscriminado de los recursos de la naturaleza, especialmente en la tala y quema de bosques. Lo que ha afectado el medio ambiente, generando la desaparición paulatina de muchas especies importantes de la flora y la fauna, entre otras. El presente estudio se realiza desde una mirada cualitativa, describiendo las causas que han obligado a la comunidad de San Rafael a destruir con diferentes actividades los árboles nativos de importantes especies en el entorno. Para el logro de los objetivos se aplicaron entrevistas estructuradas a los estudiantes y pobladores del municipio. Como conclusiones es importante mencionar que la deforestación en el municipio de San Sebastián ha disminuido en comparación con años anteriores, sin embargo, se debe seguir trabajando en temas de educación ambiental.The objective of this research was to present the current state of deforestation, as one of the actions of man in the indiscriminate use of natural resources, especially in the felling and burning of forests. What has affected the environment, generating the gradual disappearance of many important species of flora and fauna, among others. The present study is carried out from a qualitative perspective, writing the causes that have forced the community of San Rafael to destroy with different activities the native trees of important species in the environment. In order to achieve the objectives, a structured interview was applied to the students and residents of San Rafael. As conclusions, it is important to mention that deforestation in the municipality of San Sebastián has decreased compared to previous years, however, work should continue on environmental education issues

Phase Unwrapping using Chebyshev Polynomials

Phase unwrapping is an intermediate step for interferogram analysis. The phase associated with an interferogram can be estimated using a curve mesh of functions. Each of these functions can be approximated by a linear combination of basis functions. Chebyshev polynomials in addition to being a family of orthogonal polynomials can be defined recursively. In this work a method for phase unwrapping using Chebyshev polynomials is proposed. Results show good performance when applied to synthetic images without noise and also to synthetic images with noise

Phase unwrapping using a regular mesh grid

Phase unwrapping is a key step in the fringe pattern analysis. Although there are many algorithms for recovering continuous phase from wrapped phase maps, many of them are computationaly heavy, even for smooth phase maps. The smoothness characteristics of a phase map allow the use of radial basis functions to model the unwrapped phase. This method helps to reduce the processing time when unwrapping the phase. The processing time can be reduced even more when the reconstruction does not take into account all the pixels of the phase map image. In this paper we describe an algorithm for phase unwrapping where the phase map is reconstructed from a subset of pixels of the phase image using radial basis functions (RBFs). The proposed method is compared with the algorithm based on the same radial basis functions (RBFs) but using all the phase image pixels

An alternative approach to the tomographic reconstruction of smooth refractive index distributions

Continuous, mathematically smooth Phase Objects with radial symmetry are reconstructed from cross sections of their refractive index distribution by a novel method, consisting of a linear combination of Gaussian basis functions, whose technical details are discussed. As an application example, this approach is used to get a fast and accurate estimation of the temperature distribution of an actual soldering tip

An alternative method for phase-unwrapping of interferometric data

In this paper we present a novel algorithm for phase unwrapping where only a subset of data from the wrapped phase map is used to reconstruct the unwrapped phase map as a linear combination of radial basis functions (RBF’s). For noisy phase maps this algorithm gives better results than three reference algorithms based on radial basis functions, Zernike polynomials and path dependent phase unwrapping strategies

Pandrug-resistant Acinetobacter baumannii from different clones and regions in Mexico have a similar plasmid carrying the blaOXA-72 gene

BackgroundMultidrug-resistant Acinetobacter baumannii is a common hospital-acquired pathogen. The increase in antibiotic resistance is commonly due to the acquisition of mobile genetic elements carrying antibiotic resistance genes. To comprehend this, we analyzed the resistome and virulome of Mexican A. baumannii multidrug-resistant isolates.MethodsSix clinical strains of A. baumannii from three Mexican hospitals were sequenced using the Illumina platform, the genomes were assembled with SPAdes and annotated with Prokka. Plasmid SPAdes and MobRecon were used to identify the potential plasmid sequences. Sequence Type (ST) assignation under the MLST Oxford scheme was performed using the PubMLST database. Homologous gene search for known virulent factors was performed using the virulence factor database VFDB and an in silico prediction of the resistome was conducted via the ResFinder databases.ResultsThe six strains studied belong to different STs and clonal complexes (CC): two strains were ST208 and one was ST369; these two STs belong to the same lineage CC92, which is part of the international clone (IC) 2. Another two strains were ST758 and one was ST1054, both STs belonging to the same lineage CC636, which is within IC5. The resistome analysis of the six strains identified between 7 to 14 antibiotic resistance genes to different families of drugs, including beta-lactams, aminoglycosides, fluoroquinolones and carbapenems. We detected between 1 to 4 plasmids per strain with sizes from 1,800 bp to 111,044 bp. Two strains from hospitals in Mexico City and Guadalajara had a plasmid each of 10,012 bp pAba78r and pAba79f, respectively, which contained the blaOXA-72 gene. The structure of this plasmid showed the same 13 genes in both strains, but 4 of them were inverted in one of the strains. Finally, the six strains contain 49 identical virulence genes related to immune response evasion, quorum-sensing, and secretion systems, among others.ConclusionResistance to carbapenems due to pAba78r and pAba79f plasmids in Aba pandrug-resistant strains from different geographic areas of Mexico and different clones was detected. Our results provide further evidence that plasmids are highly relevant for the horizontal transfer of antibiotic resistance genes between different clones of A. baumannii