Megahertz Schlieren Imaging of Shock Structure and Sound Waves in Under-Expanded, Impinging Jets

The accompanying fluid dynamics videos visualize the temporal evolution of shock structures and sound waves in and around an under-expanded jet that is impinging on a rigid surface at varying pressure ratios. The recordings were obtained at frame rates of 500 kHz to 1 Mhz using a novel pulsed illumination source based on a high power light emitting diode (LED) which is operated in pulsed current mode synchronized to the camera frame rate.Comment: Contribution to "Gallery of Fluid Motion", 63rd Annual APS-DFD Meeting, Long Beach (CA

Submarino USFQ

The project is about developing a motorized platform operated by remote control. The platform will have vision and control systems, and navigation sensors. The ultimate goal is to design and build an underwater vehicle operated by remote control which allows the gathering of data from the environment, and the recording of audio and video. In order to be used as a tool for exploration and documentation of marine life.El proyecto consiste en desarrollar una plataforma motorizada operada a control remoto. La plataforma poseerá sistemas de control y visón, y sensores de navegación El objetivo final es diseñar y construir un vehículo submarino operado a control remoto que permita tomar datos del entorno, grabar audio y video. Con el objetivo de ser utilizada como herramienta para la exploración y documentación de la vida marina. Como primera etapa del proyecto, se realizará una investigación sobre los robots submarinos existentes. Con esta información y en base a los requerimientos de la zona se procederá a desarrollar un diseño mecánico detallado del vehículo. El diseño definirá las dimensiones del vehículo, la instalación de los diferentes componentes electrónicos, y los planos de construcción para el vehículo

Health benefits and control costs of tightening particulate matter emissions standards for coal power plants - The case of Northeast Brazil.

Exposure to ambient particulate matter (PM) caused an estimated 4.2 million deaths worldwide in 2015. However, PM emission standards for power plants vary widely. To explore if the current levels of these standards are sufficiently stringent in a simple cost-benefit framework, we compared the health benefits (avoided monetized health costs) with the control costs of tightening PM emission standards for coal-fired power plants in Northeast (NE) Brazil, where ambient PM concentrations are below World Health Organization (WHO) guidelines. We considered three Brazilian PM10 (PMx refers to PM with a diameter under x micrometers) emission standards and a stricter U.S. EPA standard for recent power plants. Our integrated methodology simulates hourly electricity grid dispatch from utility-scale power plants, disperses the resulting PM2.5, and estimates selected human health impacts from PM2.5 exposure using the latest integrated exposure-response model. Since the emissions inventories required to model secondary PM are not available in our study area, we modeled only primary PM so our benefit estimates are conservative. We found that tightening existing PM10 emission standards yields health benefits that are over 60 times greater than emissions control costs in all the scenarios we considered. The monetary value of avoided hospital admissions alone is at least four times as large as the corresponding control costs. These results provide strong arguments for considering tightening PM emission standards for coal-fired power plants worldwide, including in regions that meet WHO guidelines and in developing countries

Control of Solar Power Systems: a survey

9th International Symposium on Dynamics and Controlof Process Systems (DYCOPS 2010)Leuven, Belgium, July 5-7, 20109This paper deals with the main control problems found in solar power systems and the solutions proposed in literature. The paper first describes the main solar power technologies, its development status and then describes the main challenges encountered when controlling solar power systems.Ministerio de Ciencia y Tecnología DPI2008-05818Ministerio de Ciencia y Tecnología DPI2007-66718-C04-04Junta de Andalucía P07-TEP-0272

Training-induced gene expression plasticity in cardiac function and neural regulation for ultra-trail runners

This study aims to assess the gene regulatory response from a group of 16 athletes and to observe the plasticity induced by their training regime on the gene expression response after their participation in an 82km race. Blood samples for differential gene expression (DGE) were collected before and after this effort from two groups of runners with different training regimes: elite and active. Analyses only focused on genes annotated as related to cardiac function (CF) and neural regulation (NR) from the KEGG PATHWAY Database. Thus, 13 pathways were considered accounting for a total of 629 genes. Training regime modulated the response to exercise based on a list of 18 ranked genes with significant DGE for elite runners while remained statistically insignificant for active athletes. UQCR11, COX7C and COX4I1 genes, related to mitochondrial respiratory chain, were down-regulated which may indicate mitochondrial function impairment in cardiac muscle. Increased expression levels were obtained for PIK3R2, PLCG2, IRAK3 genes from the positive signaling cascades of neurotrophins pathway, which may reveal an improved heart rate control thanks to a better cardiac sympathetic innervation.Postprint (author's final draft

Functional responses of cougars (Puma concolor) in a multiple prey-species system

The study of predator-prey interactions is commonly analyzed using functional responses to gain an understanding of predation patterns and the impact they have on prey populations. Despite this, little is known about predator-prey systems with multiple prey species in sites near the equator. Here we studied the functional response of cougars (Puma concolor) in Sierra Nanchititla Natural Reserve (Mexico), in relation to their main prey, armadillo (Dasypus novemcinctus), coati (Nasua narica) and white-tailed deer (Odocoileus virginianus). Between 2004 and 2010, cougar scats were collected along five transects to estimate the consumption of different prey species. A relative abundance index (RAI) was calculated for each prey species and cougar using 18 camera traps. We compared Holling type I, II and III functional response models to determine patterns in prey consumption based on the relative abundance and biomass of each prey species consumed. The three main prey species comprised 55% (armadillo), 17% (coati) and 8% (white-tailed deer) of the diet. Type I and II functional responses described consumption of the two most common prey species armadillos and coati similarly well, while a type I response best characterized consumption of white-tailed deer. A negative correlation between the proportions of armadillo versus coati and white-tailed deer biomass in cougar scats suggests switching to consume alternative prey, confirming high foraging plasticity of this carnivore. This work represents one of the few studies to compare functional responses across multiple prey species, combined with evidence for prey switching at low densities of preferred prey

Estudio del estándar iec 61850 y su aplicabilidad en la integración del sector eléctrico del Ecuador

El capítulo 2 hablara sobre los adelantos tecnológicos que representa la norma, tratando de hacer un contraste con las normas usadas en el pasado y la actual, demostrando así los múltiples beneficios que esta representa. En el tercer capítulo se habla sobre los sistemas de generación distribuidos, sobre las ventajas que presentan sobre los sistemas centralizados tradicionales. El cuarto capítulo describe el análisis económico de la implementación, por medio de los índices de valor actual neto (VAN) y tasa interna de retorno (TIR)Hoy en día se la tendencia en el sector eléctrico es hacia la automatización de los procesos que involucran la generación, transmisión y distribución. Para lograr dicha automatización es necesario mantener todas las partes del sistema comunicadas entre ellas, esto se logro con la implementación de la norma IEC 61850La presente tesis tiene como objetivo describir dicha norma así como algunas de sus aplicaciones prácticas. El documento se divide en 4 capítulos. El primer capítulo habla sobre las generalidades de la norma, también se buscara explicar la necesidad de un estándar común en cuanto comunicación de dispositivos

El ser y el ente en la época tecnológica

This is a reflection that assumes that man, defined as a technological animal from its most remote moment as Homo sapiens, molded its nature while crafting tools that have led him from being an axe-maker to creating an electric culture first, then an electronic one, and finally a virtual one. In other words, what these reflections ultimately want to show is that our common human condition is on the verge of a qualitative leap as decisive as the one that occurred in the Neolithic. Is the technological era that we belong to producing unprecedented changes in the human condition? We propose to answer this question by relating the ideas of Husserl and Heidegger in order to find the being of the entity when they are determined by what technology can or cannot do. We thus propose to approach the structure of human experience from the postulates of Heideggerian phenomenology and ontology. Thus, by relating the philosophical tradition with the latest findings about what technology is doing to us, it will be possible to shed light on things to come.Esta es una reflexión que asume que el hombre, definido como animal tecnológico desde su más remoto momento como Homo sapiens, moldeó su naturaleza mientras fue elaborando herramientas que lo condujeron de ser un fabricante de hachas a crear un cultura eléctrica primero, electrónica luego y virtual después. En otras palabras, lo que quieren mostrar estas reflexiones, en último término, es que nuestra común condición humana se encuentra ad portas de un salto cualitativo tan decisivo como el que ocurrió en el Neolítico. ¿Está produciendo la era tecnológica de la que formamos parte cambios sin precedentes en la condición humana? Busco responder relacionando las ideas de Husserl y Heidegger para dar con el ser del ente cuando son determinados por lo que la tecnología puede o no hacer. Propongo así abordar la estructura de la experiencia humana desde los postulados de la fenomenología y la ontología heideggeriana. Así, poniendo en relación la tradición filosófica con los últimos hallazgos acerca de lo que la tecnología está haciéndonos, será posible echar luces sobre lo por venir

COVID-19 in Latin America and the Caribbean: what is known about the status of school reopening?

Since December 2019, the world has been facing a rapid increase in cases and deaths from the new coronavirus (COVID-19), forcing a response from countries all over the world to stop its transmission. Thus, at the beginning of April, 172 nations closed their schools, affecting >84.8% (~1484 million) of students enrolled worldwide,1 aiming to reduce the exposure to the virus, a social measure previously used to control the H1N1 influenza pandemic.2Revisión por pare