Optimization of Electrical Validation and Debug Time in Reference Clocks

La Validación Eléctrica y depuración, a nivel de sistema, de las señales de reloj de referencia, requiere muchos conocimientos y habilidades de Integridad de Señal y Alta Frecuencia. La intención de este trabajo es mejorar la metodología de validación actual e incrementar el conocimiento técnico, de esta manera nuestro equipo de validación podrá encontrar defectos y causas raíz rápidamente. Estaremos analizando, modelando y simulando los principales cuatro casos de depuración vistos en los ciclos de validación anteriores, diseñando y utilizando búferes de reloj con impedancia controlada, así como líneas de transmisión. El resultado obtenido es que, aparte de haber creado habilidades y conocimiento, también estamos observando muy buena correlación entre la simulación y el comportamiento real de nuestros productos

Integrated Curriculum: Its Use, Initiation and Support in Midwestern Schools

Survey data based on a random stratified sample of 400 schools were utilized to compare schools that use integrated, interdisciplinary or multidisciplinary curriculum (IC) with those that do not (No IC). This study explores the extent and type of use of JC, how school principals rate IC success, and differences between IC and NoIC schools in terms of their characteristics, and teacher involvement and support across different school levels. Selected data tables and analyses are presented and discussed

A low cost oscillating membrane for underwater applications at low Reynolds numbers

Active surface morphing is a nonintrusive flow control technique that can delay separation in laminar and turbulent boundary layers. Most of the experimental studies of such control strategy have been carried out in wind tunnels at low Reynolds numbers with costly actuators. In contrast, the implementation of such a control strategy at low cost for an underwater environment remains vastly unexplored. This paper explores active surface morphing at low cost and at low Reynolds for underwater applications. We do this with a 3D printed foil submerged in a water tunnel. The suction surface of the foil is covered with a magnetoelastic membrane. The membrane is actuated via two electromagnets that are positioned inside of the foil. Three actuation frequencies (slow, intermediate, fast) are tested and the deformation of the membrane is measured with an optosensor. We show that lift increases by 1%, whilst drag decreases by 6% at a Strouhal number of 0.3, i.e., at the fast actuation case. We demonstrate that surface actuation is applicable to the marine environment through an off the shelf approach, and that this method is more economical than existing active surface morphing technologies. Since the actuation mechanism is not energy intensive, it is envisioned that it could be applied to marine energy devices, boat appendages, and autonomous underwater vehicles

Facilitating Access to the Role Models of Women in STEM: W-STEM Mobile App

W-STEM is a research project funded by the European Union through the Erasmus+ program in order to develop concrete actions to modernise the government, management and operation of higher education institutions in Latin America to improve women’s access to STEM programs. Among the main objectives of the project, there is the development of a mobile app to be used in attraction campaigns conducted by the Latin American higher education institutions involved in the project. Specifically, the app aims to facilitate access to the role models of women in areas related to science, technology, engineering and mathematics. The main content inside the app will be a set of video interviews with women from different ages, cultural backgrounds, profiles, sharing their experiences about their careers, occupation and future plans. This work aims to describe the prototype of the mobile app and the exploratory study conducted with a group of students from secondary education to know their perceptions and opinions about the proposed app and the video interviews

Estudios de perfiles de profundidad AES y fotoconductividad de películas delgadas de AgInS2 preparadas por co-evaporación

In this study, thin films of AgInS2 with chalcopyrite-type tetragonalstructure were grown by means of a procedure based on the sequential evaporation of metallic precursors in presence of elemental sulfur in a two-stage process. The effect of the growth temperature and the proportion of the evaporated Ag mass in relation to the evaporated In mass (mAg/mIn) on the phase and homogeneity in the chemical composition were researched through X-ray diffraction measurements and Auger electrons spectroscopy. These measurements evidenced that the conditions for preparing thin films containing only the AgInS2 phase, grown with tetragonal chalcopyrite-type structure and good homogeneity of thechemical composition in the entire volume, are a temperature of 500 ºC and a 0.89 mAg/mIn proportionEn este trabajo se crecieron películas delgadas de AgInS2 con estructura tetragonal tipo calcopirita usando un procedimiento basado en la evaporación secuencial de precursores metálicos en presencia de azufre elemental, en un proceso en dos etapas. Se investigó el efecto de la temperatura de crecimiento y la proporción de la masa de Ag evaporada a la masa de In evaporada (mAg/mIn) sobre la fase y la homogeneidad en la composición química a través de medidas de difracción de rayos X y espectroscopía de electrones Auger. Estas medidas mostraron que las condiciones parapreparar películas delgadas que contengan únicamente la fase AgInS2, crecidas con estructura tipo calcopirita tetragonal y buena homogeneidad de la composición química en todo el volumen son temperatura de 500 °C y proporción mAg/mIn 0.89.  Las medidas de fotocorriente de transiente indicaron que el transporte eléctrico es afectado por procesos de recombinación, vía transiciones banda a banda y transiciones asistidas por trampas

AES depth profile and photoconductive studies of AgInS2 thin films prepared by co-evaporation

In this study, thin films of AgInS2 with chalcopyrite-type tetragonal structure were grown by means of a procedure based on the sequential evaporation of metallic precursors in presence of elemental sulfur in a two-stage process. The effect of the growth temperature and the proportion of the evaporated Ag mass in relation to the evaporated In mass (mAg/mIn) on the phase and homogeneity in the chemical composition were researched through X-ray diffraction measurements and Auger electrons spectroscopy. These measurements evidenced that the conditions for preparing thin films containing only the AgInS2 phase, grown with tetragonal chalcopyrite-type structure and good homogeneity of the chemical composition in the entire volume, are a temperature of 500 ºC and a 0.89 mAg/mIn proportion.En este trabajo se crecieron películas delgadas de AgInS2 con estructura tetragonal tipo calcopirita usando un procedimiento basado en la evaporación secuencial de precursores metálicos en presencia de azufre elemental, en un proceso en dos etapas. Se investigó el efecto de la temperatura de crecimiento y la proporción de la masa de Ag evaporada a la masa de In evaporada (mAg/mIn) sobre la fase y la homogeneidad en la composición química a través de medidas de difracción de rayos X y espectroscopía de electrones Auger. Estas medidas mostraron que las condiciones para preparar películas delgadas que contengan únicamente la fase AgInS2, crecidas con estructura tipo calcopirita tetragonal y buena homogeneidad de la composición química en todo el volumen son temperatura de 500 °C y proporción mAg/mIn 0.89.  Las medidas de fotocorriente de transiente indicaron que el transporte eléctrico es afectado por procesos de recombinación, vía transiciones banda a banda y transiciones asistidas por trampas

Characteristics of Mexican Leather Footwear Industry and its International Trade Activity, Correlation of Productivity, and Competitiveness

This paper focuses on analyzing the globalization effect on the Mexican leather footwear industry at a firm-level. In this work, the analysis of competitiveness is done based on the definition given by the Organization for Economic Cooperation and Development (OECD). They defined it as ‘a measure of a country's advantage or disadvantage in selling its products in international market’. The productivity of the Mexican leather footwear industry was calculated using the Latin American-KLEMS Model that relates gross output to primary (Capital and Labor) and intermediate inputs (Energy, Other intermediate goods, and Services). Furthermore, firms were categorized considering the number of employees, the annual value of production, and the commercial diversification in order to calculate the correlation Pearson coefficient. Firstly, the results show that the correlation of production value with the number of exporting companies is bigger than the correlation of the importing companies. Secondly, that the correlation of Total Productivity Factor (TPF) to exports is strong (0.7028); and finally, that the correlation of Total Productivity Factor (TPF) to imports is also significant (0.6511)

Use of nanomaterials to conserve the stone of the Roman Theatre of Cartagena

[EN] The Roman Theatre of Cartagena is an important example of the monumental architecture of Hispania. Various types of local stone were used in its construction, including a type of sandstone known as Tabaire. This paper describes the physical characteristics of Tabaire. We also identify its deterioration patterns and study its consolidation using lime nanoparticles and silicon dioxide (ethyl silicate). Initial analyses using the imaging techniques Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and X-Ray Tomography (CT) show that it is an extremely porous, soft stone. The effectiveness of the consolidating treatments was verified using non-destructive methods based on identifying dispersion and penetrability in the substrate (OM and SEM) and detecting colour variation (CIE-L*a*b*) or minimally destructive methods, such as the peeling test and Shore-D hardness, to determine their effect on the characteristics of the material.[ES] El Teatro de Cartagena es un importante exponente de la arquitectura monumental de la Hispania romana. Para su construcción fueron utilizados diversos pétreos locales, entre ellos una arenisca conocida como Tabaire. Este artículo tiene como objetivo la caracterización física del Tabaire, así como la identificación de sus formas de deterioro y el estudio de su consolidación mediante nanopartículas de cal y de dióxido de silicio (silicato de etilo). Los análisis iniciales mediante técnicas de imagen como la Microscopía Óptica (OM), Microscopía Electrónica de Barrido (SEM) y Tomografía de Rayos X (CT) muestran que es una roca de elevada porosidad y escasa dureza. La eficacia de los tratamientos consolidantes se comprobó mediante métodos no destructivos, basados en la identificación de la dispersión y penetrabilidad en el sustrato (OM y SEM) y en la detección de la variación del color (CIE-L*a*b*), o mínimamente destructivos, como el peeling test y la dureza Shore-D, para conocer su incidencia en las características del material.Navarro-Moreno, D.; Martínez-Arredondo, A.; García-Vera, VE.; Lanzón, M. (2023). Uso de nanomateriales para la conservación de la piedra del Teatro Romano de Cartagena. Loggia, Arquitectura & Restauración. (36):106-119. https://doi.org/10.4995/loggia.2023.193601061193

Differential Indicators of Diabetes-Induced Oxidative Stress in New Zealand White Rabbits: Role of Dietary Vitamin E Supplementation

Determination of reliable bioindicators of diabetes-induced oxidative stress and the role of dietary vitamin E supplementation were investigated. Blood (plasma) chemistries, lipid peroxidation (LPO), and antioxidant enzyme activities were measured over 12 weeks in New Zealand White rabbits (control, diabetic, and diabetic + vitamin E). Cholesterol and triglyceride levels did not correlate with diabetic state. PlasmaLPOwas influenced by diabetes and positively correlated with glucose concentration only, not cholesterol or triglycerides. Liver glutathione peroxidase (GPX) activity negatively correlated with glucose and triglyceride levels. Plasma and erythrocyte GPX activities positively correlated with glucose, cholesterol, and triglyceride concentrations. Liver superoxide dismutase activity positively correlated with glucose and cholesterol concentration. Vitamin E reduced plasma LPO, but did not affect the diabetic state. Thus, plasmaLPOwas the most reliable indicator of diabetes-induced oxidative stress. Antioxidant enzyme activities and types of reactive oxygen species generated were tissue dependent. Diabetes-induced oxidative stress is diminished by vitamin E supplementation