Modeling and Analysis of speed tuning of a PMSM with presence of crack using genetic algorithms

[EN] In this article, we propose the continuous system model corresponding to the Permanent Magnet Synchronous Motor (PMSM) with the presence of degradation in the rotational inertia of the rotor through the fissure mechanism, which allows the estimation of the physical parameters. We consider the diameter of the split on the rotor in the analysis of the model, and in effect, the decrease of the uncertainty of the PMSM model. The closed- loop identification of the gains is achieved by a sensibility analysis, whilst the gains obtained by the computational optimization method of search through genetic algorithms, allows the proposed model converge to the reference model.[ES] En el presente artículo se propone el modelado del sistema continuo correspondiente al motor síncrono de imanes permanentes (MSIP) con presencia de degradación en la inercia rotacional del rotor, mediante el mecanismo de fisura, lo cual permite la estimación de parámetros físicos, en el caso de análisis, el diámetro de la grieta presente en el rotor, disminuyendo con ello la incertidumbre en el modelado del MSIP. Se lleva a cabo la identificación en bucle cerrado de las ganancias mediante un análisis de sensibilidad, donde mediante el método computacional de optimización de búsqueda por algoritmos genéticos se obtienen las ganancias que logran converger el modelo propuesto al modelo de referencia.Este trabajo ha sido realizado gracias al apoyo de la beca otorgada por el consejo nacional de ciencia y tecnología (CONACYT) con número de asignación 622392, la Universidad Politécnica de Tulancingo (UPT) y la Revista Iberoamericana de Automática e Informática Industrial (RIAI), sin cuyo apoyo académico, económico y motivacional no habría podido desarrollarse el presente escrito, nuestro mayor reconocimiento y agradecimiento a todas las personas que se encuentran detrás de los citados organismos e instituciones.Manilla Garcia, A.; Rivas Cambero, I.; Monroy Anieva, J. (2019). Modelado y Análisis de Sintonización de Velocidad de un MSIP con Presencia de Fisura Mediante Algoritmos Genéticos. Revista Iberoamericana de Automática e Informática. 16(2):190-199. https://doi.org/10.4995/riai.2018.9767SWORD19019916

Comparison of the material quality of AlxIn1-xN (x ~ 0-0.50) films deposited on Si (100) and (111) by reactive RF sputtering

Here, we compare the material quality of AlxIn1-xN layers deposited on Si with different crystallographic orientations, (100) and (111), via radio-frequency (RF) sputtering. To modulate their Al content, the Al RF power was varied from 0 to 225 W, whereas the In RF power and deposition temperature were fixed at 30 W and 300oC, respectively. X-ray diffraction measurements reveal a c-axis-oriented wurtzite structure with no phase separation regardless of the Al content (x = 0-0.50), which increases with the Al power supply. The surface morphology of the AlxIn1-xN layers improves with increasing Al content and it is similar for samples grown on both Si substrates (the root-mean-square roughness decreases from 12 nm to 2.5 nm). Furthermore, from TEM images we notice a similar grain-like columnar morphology and defect density on samples deposited on both Si substrates under the same conditions. Simultaneously grown AlxIn1-xN-on-sapphire samples point to a residual n-type carrier concentration in the 1020-1021 cm-3 range. The optical band gap energy of these layers evolves from 1.75 eV to 2.56 eV with increasing Al content, consistent with the blue shift of their low-temperature photoluminescence. In general, the material quality of the AlxIn1-xN films on Si is similar for both crystallographic orientations. Nonetheless, samples deposited on sapphire show an improved structural and morphological characteristic likely due to the lower difference in lattice constants between the nitride and the sapphire substrate

On Optimal Coverage of a Tree with Multiple Robots

We study the algorithmic problem of optimally covering a tree with $k$ mobile robots. The tree is known to all robots, and our goal is to assign a walk to each robot in such a way that the union of these walks covers the whole tree. We assume that the edges have the same length, and that traveling along an edge takes a unit of time. Two objective functions are considered: the cover time and the cover length. The cover time is the maximum time a robot needs to finish its assigned walk and the cover length is the sum of the lengths of all the walks. We also consider a variant in which the robots must rendezvous periodically at the same vertex in at most a certain number of moves. We show that the problem is different for the two cost functions. For the cover time minimization problem, we prove that the problem is NP-hard when $k$ is part of the input, regardless of whether periodic rendezvous are required or not. For the cover length minimization problem, we show that it can be solved in polynomial time when periodic rendezvous are not required, and it is NP-hard otherwise

The COVID-19 Student Stress Questionnaire: Validation in Spanish university students from health sciences

This study aimed to validate the Spanish version of the COVID-19 Student Stress Questionnaire (CSSQ), a 7-item tool assessing COVID-19-related stressors among university students, namely, Relationships and Academic Life, Isolation, and Fear of Contagion. Participants were 331 Spanish university students. Factor analyses sustained the three factor solution of the original tool. Data also revealed satisfactory convergent and discriminant validity, suitable internal consistency, and significant associations with psychological symptoms, as measured by the Symptom Checklist-90-Revised. The Spanish version of the CSSQ represents a valid tool to be used in clinical settings to timely identify students at high psychological risk and to develop evidence-based interventions during/after the pandemic

The IL-4/STAT6/PPARγ signaling axis is driving the expansion of the RXR heterodimer cistrome, providing complex ligand responsiveness in macrophages

Retinoid X receptor (RXR) is an obligate heterodimeric partner of several nuclear receptors (NRs), and as such a central component of NR signaling regulating the immune and metabolic phenotype of macrophages. Importantly, the binding motifs of RXR heterodimers are enriched in the tissue-selective open chromatin regions of resident macrophages, suggesting roles in subtype specification. Recent genome-wide studies revealed that RXR binds to thousands of sites in the genome, but the mechanistic details how the cistrome is established and serves ligand-induced transcriptional activity remained elusive. Here we show that IL-4-mediated macrophage plasticity results in a greatly extended RXR cistrome via both direct and indirect actions of the transcription factor STAT6. Activation of STAT6 leads to chromatin remodeling and RXR recruitment to de novo enhancers. In addition, STAT6 triggers a secondary transcription factor wave, including PPARγ. PPARγ appears to be indispensable for the development of RXR-bound de novo enhancers, whose activities can be modulated by the ligands of the PPARγ:RXR heterodimer conferring ligand selective cellular responses. Collectively, these data reveal the mechanisms leading to the dynamic extension of the RXR cistrome and identify the lipid-sensing enhancer sets responsible for the appearance of ligand-preferred gene signatures in alternatively polarized macrophages

A novel targeted/untargeted GC-Orbitrap metabolomics methodology applied to Candida albicans and Staphylococcus aureus biofilms

Introduction: Combined infections from Candida albicans and Staphylococcus aureus are a leading cause of death in the developed world. Evidence suggests that Candida enhances the virulence of Staphylococcus—hyphae penetrate through tissue barriers, while S. aureus tightly associates with the hyphae to obtain entry to the host organism. Indeed, in a biofilm state, C. albicans enhances the antimicrobial resistance characteristics of S. aureus. The association of these microorganisms is also associated with significantly increased morbidity and mortality. Due to this tight association we hypothesised that metabolic effects were also in evidence. Objectives: To explore the interaction, we used a novel GC-Orbitrap-based mass spectrometer, the Q Exactive GC, which combines the high peak capacity and chromatographic resolution of gas chromatography with the sub-ppm mass accuracy of an Orbitrap system. This allows the capability to leverage the widely available electron ionisation libraries for untargeted applications, along with expanding accurate mass libraries and targeted matches based around authentic standards. Methods: Optimised C. albicans and S. aureus mono- and co-cultured biofilms were analysed using the new instrument in addition to the fresh and spent bacterial growth media. Results: The targeted analysis experiment was based around 36 sugars and sugar phosphates, 22 amino acids and five organic acids. Untargeted analysis resulted in the detection of 465 features from fresh and spent medium and 405 from biofilm samples. Three significantly changing compounds that matched to high scoring library fragment patterns were chosen for validation. Conclusion: Evaluation of the results demonstrates that the Q Exactive GC is suitable for metabolomics analysis using a targeted/untargeted methodology. Many of the results were as expected: e.g. rapid consumption of glucose and fructose from the medium regardless of the cell type. Modulation of sugar-phosphate levels also suggest that the pentose phosphate pathway could be enhanced in the cells from co-cultured biofilms. Untargeted metabolomics results suggested significant production of cell-wall biosynthesis components and the consumption of non-proteinaceous amino-acids