Introducción— En el presente artículo se expone el diseño y la implementación de una Estación de Medida de Radiación UltraVioleta (UV), conocida como Solmáforo, energizado por un sistema fotovoltaico ...aislado y manejo de información vía web haciendo uso del concepto Internet de las Cosas (IoT). Se presenta la implementación de un sistema que registra y muestra, de diferentes formas, el índice de radiación UltraVioleta (IUV) del lugar, haciendo uso de la técnica Timer Off, la cual es usada para reducir el consumo energético. Para el diseño del dispositivo se utilizó la metodología Top Down, comenzando desde un nivel superior, y dividiendo en módulos con un ciclo de verificación y simulación para un óptimo rendimiento a nivel de consumo energético. Para el bosquejo del sistema fotovoltaico aislado se utilizó el software “Herramienta para el Dimensionamiento de Sistemas Fotovoltaicos Aislados (DFSA)” desarrollado por los investigadores y en el cual se encuentra la base de datos de la radiación solar en el campus universitario. La estación está localizada en un espacio al aire libre del campus de la Universidad del Quindío, con el fin de mantener a la comunidad informada visualmente acerca de los niveles de radiación (UV). La visualización del IUV y la información de la exposición de radiación UV adecuada del cuerpo se hace de acuerdo bajo la Organización Mundial de la Salud (OMS). La visualización de las variables se hace en tiempo real por medio de una interfaz virtual implementada en Python y los datos almacenados en MySQL. Objetivo— Desarrollar un sistema electrónico que permita la visualización del IUV en la Universidad del Quindío y presente información preventiva a la comunidad usando el concepto IoT. Metodología— En este aspecto se comenzó con el marco teórico relacionado con los rayos solares y la radiación UV, para luego implementar una estación de medición con acceso al público del campus universitario, generando mensajes informativos de precaución. Luego con la metodología Top Down se divide cada parte del proyecto en submódulos que genera una mejor búsqueda y asentamiento de los materiales y métodos a utilizar. Resultados— Al comprobar dos métodos para el cálculo del IUV, el propuesto por ROHM y el propuesto por Zhang y Huang, se demuestra que el último es el más apto. Esto permite que el sistema entregue mejor información de los cambios de radiación UV, además de que se comprueba que los cambios de temperatura y humedad son directamente proporcionales a los cambios de radiación UV. Finalmente, al implementar la técnica Timer Off, el consumo energético del todo el sistema baja y las 4 horas de autonomía que se esperaba al usar la energía almacenada en las baterías, pasa a ser de 5 hasta 7 horas. Conclusiones— La construcción de la estación de medición de rayos UV energizado por un sistema fotovoltaico cumple con el propósito de sensibilizar a la gente sobre el peligro de la alta exposición de los rayos UV y las recomendaciones que deben seguir para evita los más posible este tipo de inconvenientes. Además, implementa metodologías modernas sobre el consumo de energía como el uso del método Time Off y de energía renovables al usar panales para almacenar la energía de la radiación solar, convirtiendo en un sistema de medición autónomo, además, hace uso del concepto del IoT en el desarrollo de plataformas vía web y el uso de sistemas de comunicación inalámbricas.
High-performance aromatic polyamides García, José M.; García, Félix C.; Serna, Felipe ...
Progress in polymer science,
05/2010, Letnik:
35, Številka:
5
Journal Article
Recenzirano
Wholly aromatic polyamides (aramids) are considered to be high-performance organic materials due to their outstanding thermal and mechanical resistance. Their properties arise from their aromatic ...structure and amide linkages, which result in stiff rod-like macromolecular chains that interact with each other via strong and highly directional hydrogen bonds. These bonds create effective crystalline microdomains, resulting in a high-level intermolecular packing and cohesive energy. The better known commercial aramids, poly(
p-phenylene terephthalamide) and poly(
m-phenylene isophthalamide), are used in advanced technologies and have been transformed into high-strength and flame resistant fibers and coatings, with applications in the aerospace and armament industry, bullet-proof body armor, protective clothing, sport fabrics, electrical insulation, asbestos substitutes, and industrial filters, among others. Owing to their chemical structure, they exhibit extremely high transition temperatures that lie above their decomposition temperatures, are sparingly soluble in common organic solvents and, accordingly, can only be transformed upon solution. Research efforts are therefore underway to take advantage of their properties, enhance their processability and solubility, and incorporate new chemical functionalities in the polyamide backbone or lateral structure, so that their applicability is expanded and remains on the forefront of scientific research.
Films and water soluble polymers as sensory materials for the detection and quantification of iron, cobalt, copper and tin salts in water, and for forensic applications.
•Fe(III), Co(II), Cu(II) and ...Sn(II) were detected and discriminated in water colorimetrically.•Colorimetric sensory polymers having terpyridine motifs in their structure were prepared.•A water soluble polymers allowed for the preparation of aqueous sensing solutions.•Film shaped solid sensory membranes permitted the preparation of manageable solid sensory kits.•Positive images of iron tools previously handled do anticipate future forensic applications.
Colorimetric cation responsive water soluble polymers and manageable films or membranes have been designed. The sensory materials respond with a colour change to the presence in water of Fe(III), Co(II), Cu(II), and Sn(II). The colour change is specific of each metal cation, and enables its identification (purple for iron, orange for cobalt, green for copper, and yellow for tin). The design of the materials relies on an addition monomer having a terpyridine moiety, which behaves as a dye in presence of transition metal cations due to its proven chelating capability towards these species and the colour development that always accompany the metallic complex formation. Water solutions of the sensory linear polymers allow for the UV/vis titration of Fe(III), Co(II), Cu(II), and Sn(II) with a limit of detection of 1.3×10−7, 6.4×10−8, 1.3×10−5 and 1.4×10−5M, respectively. On the other hand, sensory kits, cut from sensory membranes, permitted the visual quantification of the cations in a dynamic range of five decades (1×10−7 to 5×10−3M) for Fe(III) and Co(II) and of two decades (9×10−5 to 9×10−3M) for Cu(II) and Sn(II). Titration curves can also be drawn from a picture taken to the sensory kits with a smartphone, by using the digital colour definition of the materials as analytical signal. Also, after entering into contact with hands, shapes of metallic objects (iron and cobalt containing tools) can be colour revealed by pressing the hands on paper or cotton fabrics wetted with water solutions of the linear sensory polymer.
Introducción: el hipotiroidismo es una endocrinopatía caracterizada por la acción o la producción deficiente de las hormonas tiroideas en el organismo. Una de las etiologías menos frecuentes es la ...disfunción en las desyodasas, la cual puede sospecharse cuando el perfil tiroideo evidencia hormona tiroestimulante (TSH) elevada, tiroxina (T4) libre alta con triyodotironina (T3) total o libre baja.Objetivo: dar a conocer un caso de hipotiroidismo tratado exitosamente con selenio y levotiroxina, así como describir el papel del selenio en la enfermedad tiroidea.Presentación del caso: hombre de 22 años con alteraciones en el perfil tiroideo caracterizado por TSH y T4 libre altas y T3 en el límite inferior, sin hallazgo de adenomas de hipófisis, mutaciones en el gen receptor de hormona tiroidea (THRB)o alteraciones en las globulinas transportadoras de tiroxina, que se trató exitosamente con suplencia de hormona tiroidea y selenio.Discusión y conclusión: frente a concentraciones anómalas en los niveles de TSH, T4 y T3, no fácilmente explicables por otras causas, las alteraciones en la síntesis o función de las desyodasas deben considerarse. El tratamiento con selenio y levotiroxina podría ayudar en el manejo de esta patología.
El floricultor colombiano no puede desconocer los cambios en tendencias de consumo ni la consolidación del canal retail en su mercado principal, usa.El cuál generará un alto impacto en las ...características del negocio y el papel de los jugadores en la cadena de suministros. El objetivo de este estudio exploratorio utilizando casos múltiples, es presentar un marco de oportunidades para fortalecer la comercialización de la flor y estructurar canales de distribución acordes a las necesidades del consumidor norteamericano y a los cambios en los hábitos de compra. Las conclusiones, proponen las acciones a emprender por las empresas floriculturas estudiadas a fin de incrementar su competitividad y resolver su dilema actual: contraer oferta para mejorar el precio de venta o incrementar demanda.
Colombian flower growers should not ignore current consumption trends or the consolidation of the retail sales channel in its primary market, usa.These trends are going to have an impact on the characteristics of the business and the roles of players in the supply chain. The objec-tive of this exploratory study based on a review of multiple cases is to present a framework of opportunities to strengthen the trade of flowers and structure distribution channels that suit the needs and changes in the purchasing habits of North American consumers. The findings propose a series of actions to be taken by flower growers in order to increase their competiti-veness and profitability and resolve the current dilemma they are now facing about whether to reduce supply and improve the sales price or increase demand.
O floricultor colombiano não pode desconhecer as mudanças das tendências de consumo nem a consolidação do canal de varejo em seu mercado principal, os EUA. O qual gera um alto impacto nas características do negócio e no papel dos intervenientes na cadeia de suprimento. O objetivo desse estudo exploratório usando múltiplos casos, é apresentar um marco de oportunidades para fortalecer a comercialização das flores e estruturar canais de distribuição de acordo com as necessidades do consumidor norte americano a às mudanças nos hábitos de compra. As conclusões propõem as ações a empreender pelas empresas floricultoras estudadas a fim de incrementar sua competitividade e resolver seu dilema atual: proposta contratual para melhorar o preço de venda ou incrementar a procura.
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•Film-shaped solid sensory membranes and sensory polymer-coated fibers allowed the preparation of manageable solid sensory kits.•Colorimetric sensory polymers had palladium in their ...structure.•Sensory polymers enabled the detection of cyanide in both aqueous and gas phases.
We have prepared solid sensory materials for the visual detection of cyanide in 100% water solutions and gas phases. The materials are hybrid polymers that were prepared from a palladium-containing acrylic monomer for use as sensory films and smart textiles.
This paper describes a strategy followed to achieve a sensing phenomenon in aqueous media using water-insoluble organic molecules. A sensory polymeric material for the colorimetric sensing of cyanide ...in water has been developed based on the reactivity of this anion with a fluorene derivative.
Selective and sensitive solid sensory substrates for detecting Al(III) in pure water are reported. The material is a flexible polymer film that can be handled and exhibits gel behavior and membrane ...performance. The film features a chemically anchored salicylaldehyde benzoylhydrazone derivative as an aluminum ion fluorescence sensor. A novel procedure for measuring Al(III) at the ppb level using a single solution drop in 20 min was developed. In this procedure, a drop was allowed to enter the hydrophilic material for 15 min before a 5 min drying period. The process forced the Al(III) to interact with the sensory motifs within the membrane before measuring the fluorescence of the system. The limit of detection of Al(III) was 22 ppm. Furthermore, a water-soluble sensory polymer containing the same sensory motifs was developed with a limit of detection of Al(III) of 1.5 ppb, which was significantly lower than the Environmental Protection Agency recommendations for drinking water.
This study developed sensory polymeric materials for the colorimetric sensing of TNT in aqueous media. Solid films and coated fabrics permitted the detection of TNT, through colour change, and its ...quantification, by taking a picture of the materials and processing their RGB parameters to define the evolved colour.
Iron in blood serum, wine and water has been visually detected and quantified quickly by processing photographs of an iron colorimetric sensory polymer substrate. The photographs may be taken with a ...conventional digital camera or Smartphone. The sensory materials were designed following a straightforward strategy. A proven iron organic chelator was easily transformed into an acrylic monomer and further copolymerized with hydrophilic co-monomers to render a membrane comprised of a hydrophilic, gel-like, polymer network. The film-like membrane generated was cut into small-diameter sensory discs. Thus, upon immersion of the sensory disks in blood serum, wine, and water, a colour development was rapidly observed which could be easily correlated with the iron concentration of the samples. RGB digital parameters obtained from photographs of the sensors were processed statistically using principal component analysis (PCA) and used to elaborate titration curves and quantify iron concentrations. The response time of the sensory films was short, 15 min, and the concentrations measured in water ranged from 56 ppb to 56 ppm. This broad range covers the U.S. Environmental Protection Agency (EPA) and European Union (EU) drinking water standards for iron in drinking water (<300 and 200 ppm, respectively), the typical iron content in wines (1 to 10 ppm) and the normal range of iron in the blood serum in men (0.8-1.8 ppm). This methodology for detecting and quantifying chemical species avoids the time-consuming sample preparation, expensive laboratory techniques, and specialized personnel needed to carry out conventional analytical methods.
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