194 research outputs found
Automated sequence design of nucleic acid hybridization reactions for microRNA detection
[EN] microRNA (miRNA) can be found in a variety of biological samples and then they
represent important molecular markers for early diagnostic strategies. This work (TFG)
explores a novel approach based on nested non-enzymatic and enzymatic biochemical
processes in vitro. In particular, an automated sequence design algorithm of nucleic acid
hybridization reactions for microRNA detection is developed.[ES] Los microRNAs (miRNAs) pueden ser hallados en una gran variedad de muestras
biológicas y suponen una fuente importante de marcadores moleculares para
estrategias de diagnóstico tempranas. En este trabajo (TFG), se explora un abordaje
novedoso basado en procesos bioquímicos anidados enzimáticos y no enzimáticos in
vitro. Particularmente, se desarrolla un algoritmo de diseño de secuencias automatizado
para reacciones de hibridación de ácidos nucleicos para la detección de microRNA.Goiriz Beltrán, L. (2019). Automated sequence design of nucleic acid hybridization reactions for microRNA detection. http://hdl.handle.net/10251/125058TFG
Experimental determination of drift loss from a cooling tower with different drift eliminators using the chemical balance method
The existence of cooling towers arises from the need to evacuate power to the environment
from engines, refrigeration equipment and industrial processes. Water drift emitted from cooling towers is objectionable for several reasons, mainly due to human health hazards. It is common practice to fit drift eliminators to cooling towers in order to minimise water loss from the system. The presence of the drift eliminator mainly affects two aspects of cooling towers: their thermal performance and the amount of water drift loss. This paper experimentally studies the drift loss emissions from a cooling tower without drift eliminator and fitted with six different drift eliminators. Chemical Balance is the selected method and Australian Standard methodology is taken as a reference. Some modifications are
proposed to reduce uncertainty by increasing the duration of the test and the number of water samples. Installation of a drift eliminator, even in the worst case, reduces the water drift level to less than half of the situation without the eliminator. The water drift losses obtained with the different drift eliminators installed at the pilot plant, from 0.0118% to 0.161%, are within the range generally reflected in the literature. Finally, a criterion for designing drift eliminators in order to optimise both the collection efficiency and the cooling tower's thermal performance is proposed.This research has been partially financed by the project DPI2007-66551-C02-01 grant from the “Dirección General de Industria, M. de Ciencia y Tecnología”, the project 2I05SU0029 grant of the “Secretaría General de la Consejerí de Educación
y Cultura de la C.A. de la Región de Murcia” and the HRS Spiratube Company, Murcia (Spain)
Three-dimensional quasi-conformal transformation optics through numerical optimization
In this paper we demonstrate the possibility to achieve 3-dimensional quasi-conformal transformation optics through parametrization and numerical optimization without using sliding boundary conditions. The proposed technique, which uses a quasi-Newton method, is validated in two cylindrical waveguide bends as design examples. Our results indicate an arbitrarily small average anisotropy can be achieved in 3D transformation optics as the number of degrees of freedom provided by the parametrization was increased. The waveguide simulations confirm modal preservation when the residual anisotropy is neglected24151646516470CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIGFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPnão temnão temnão temnão temnão te
On the influence of psychrometric ambient conditions on cooling tower drift deposition
Water drift emitted from cooling towers is objectionable for several reasons, mainly due to human health reasons. A numerical model to study the influence of sychrometric ambient conditions on cooling tower drift deposition was developed. The mathematical model presented, consisting of two coupled sets of conservation equations for the continuous and discrete phases, was incorporated in the general purpose CFD code Fluent. Both experimental plume performance and drift deposition were employed to validate the numerical results. This study shows the influence of variables like ambient dry bulb temperature, ambient absolute humidity and droplet exit temperature from cooling tower on the drift evaporation (and therefore deposition) and on the zone affected by the cooling
tower. The stronger effect detected corresponds to the ambient dry bulb temperature.
When a higher ambient temperature was present, deposition was lower (evaporation was therefore higher) and the zone affected by the cooling tower was smaller. The influence of the other two variables included in the study was weaker than the one corresponding to the dry bulb ambient temperature. A high level of ambient absolute humidity increased drift deposition and also the size of the zone affected by the cooling tower. Finally, a high level
of droplet exit temperature decreased deposition and increased the zone affected by the cooling tower
The dry and adiabatic fluid cooler as an alternative to cooling towers: an experimental view.
Energy and environmental implications of a refrigeration cycle are largely conditioned by the choice of condensing system. Conventional solutions transfer heat to water, and recirculated through cooling towers or to atmospheric air through a dry condenser. While the use of cooling towers means less energy consumption due to lower pressure in the condenser, a number of environmental implications are questioning their installation. Mainly, it represents an emission of chemicals or microorganisms to the atmosphere as Legionella. The dry and adiabatic fluid cooler works as a standard fluid dry cooler enhancing the dry cooler’s capacity with adiabatic pre-cooling of the air intake. The ambient dry bulb temperature is reduced as the air passes through an evaporative pad especially designed to humidify and cool the air (Figure.1). The main objective of this study is to experimentally investigate the thermal performance of a dry and adiabatic fluid cooler. With the experimental data, a thermal model will be developed in order to compare the energy implications arising from the replacement of traditional systems (dry condenser and cooling towers) by condensing air coolers with adiabatic pre-cooling.The construction of the prototype has been sponsored by the Regional Government of the Comunidad Valenciana, through the Project GV/2011/072.
The instrumentation used to conduct experimental work has been funded through the Project “Estudio energético de un sistema alternativo para la condensación en ciclos de refrigeración: el aero-refrigerador con preenfriamiento adiabático” from Convocatoria 2009 de Proyectos Bancaja-UMH para grupos precompetitivo
Experimental study on the performance of a mechanical cooling tower fitted with different types of water distribution systems and drift eliminators.
Cooling towers are evaporative heat transfer devices in which atmospheric air cools warm water, with direct contact between the water and the air by evaporating part of the water. The principle of operation of cooling towers requires spraying or distributing water over a heat transfer surface (packing) across or through which a stream of air is passing. As a result, water droplets are incorporated in the air stream and,depending on the velocity of the air, will be taken away from the unit. This is known as drift. Although cooling tower drift is objectionable for several reasons, the most hazardous problem concerning human health is the emission of chemicals or microorganisms into the atmosphere. Undoubtedly, regarding
microorganisms, the most well-known pathogens are the multiple species of bacteria collectively known as legionella.
The binomial water distribution system-drift eliminator is identified to be that mainly responsible for cooling tower drift. While water distribution systems affect the mechanics of setting up the drops, drift
eliminators work by changing the direction of the airflow and separating droplets from the airstream through inertial impact.
The drift eliminator’s performance can be quantified mainly by two factors: droplet collection efficiency and the pressure drop across the eliminator. In contrast, water distribution systems are characterized by
the pressure drop across itself and the achieved size of the particle spread. Alongside drift, the binomial water distribution system-drift eliminator affects the cooling tower performance. From the reviewed bibliography, some studies assessing the effect of the drift eliminator on cooling tower performance have been found. Nevertheless, no studies regarding the influence of the water distribution
system on the cooling tower’s performance have been detected. In this sense, this paper studies the thermal performance of a forced draft counter-flow wet cooling tower fitted with two water distribution systems (the pressure water distribution system (PWDS) and gravity water distribution system (GWDS)) for six drift eliminators for a wide range of air and water mass flow rates. The data registered in the experimental set-up were employed to obtain correlations of the tower characteristic, which defines the
cooling tower’s thermal performance. The outlet water temperature predicted by these correlations was compared with the experimentally registered values, obtaining a maximum averaged difference of ±0.95%.The authors wish to acknowledge the collaboration of the Ministerio de Educación y Ciencia (Spanish Education and Science Ministry) for their support of project PN I+D+I 2008-2011 ENE2010-21679-C02-
02
Experimental study on the performance of a mechanical cooling tower fitted with different types of water distribution systems.
Cooling towers are evaporative heat transfer devices in which atmospheric air cools warm water, with direct contact between the water and the air, by evaporating part of the water. As a result, water droplets are incorporated in the air stream and, depending on the velocity of the air, will be taken away from the unit. This is known as drift. Although cooling tower drift is objectionable for several reasons, the most hazardous problem concerning human health is the emission of chemicals or microorganisms to the atmosphere. Regarding to microorganisms, the most well-known pathogens are the multiple species of bacteria collectively known as legionella.
The binomial water distribution system-drift eliminator is identified to be the main responsible of cooling tower drift. While drift eliminators work by changing the direction of the airflow and separating
droplets from the airstream through inertial impact, water distribution systems affect the mechanics of setting up the drops.
Drift eliminator’s performance can be quantified mainly by two factors. On one hand the droplet collection efficiency and, on the other hand, the pressure drop across the eliminator. In contrast, water
distribution systems are characterized by the pressure drop across itself and the achieved size of the particles spread. Although the factors mentioned above are conditioned by the binomial water
distribution system-drift eliminator, it affects mainly the quantity of water taken away from the tower and the thermal performance. From the reviewed bibliography, some studies assessing the effect of the drift eliminator on cooling tower’s performance have been found. Nevertheless no studies regarding the influence of the water
distribution system on cooling tower’s performance have been found. In this sense, this paper studies the thermal performance of a forced draft counter-flow wet cooling tower fitted with different water
distribution systems for many drift eliminators for a wide range of air and water mass flow rates. The data registered in the experimental set-up were employed to obtain correlations of the Tower
Characteristic, which defines the cooling tower’s thermal performance. The outlet water temperature predicted by these correlations was compared with the experimentally registered values, obtaining a
maximum difference of ±0.95%.Ministerio de Educación y Ciencia (Spanish
Education and Science Ministry) for their support of project PN I+D+I 2008-2011 ENE2010-21679-C02-02
Evaluación de riesgo por legionelosis de los aerorefrigeradores con preenfriamiento adiabático. Póster
Numerosas investigaciones epidemiológicas han demostrado que las torres de refrigeración y los condensadores evaporativos son fuentes de infección por Legionella. La alternativa comercial convencional para la sustitución de las torres de refrigeración son los condesadores por aire. Si desde un enfoque sanitario los condensadores por aire cobran una clara ventaja por no ser instalaciones de riesgo, desde un punto de vista energético su consumo es mayor. Además de las soluciones clásicas de condensación como son las torres de refrigeración, los condensadores evaporativos y los aerocondensadores, comercialmente están apareciendo dispositivos híbridos que buscan un compromiso entre su impacto ambiental y el consumo energético
The circumstellar disk, envelope, and bi-polar outflow of the Massive Young Stellar Object W33A
The Young Stellar Object (YSO) W33A is one of the best known examples of a
massive star still in the process of forming. Here we present Gemini North
ALTAIR/NIFS laser-guide star adaptive-optics assisted K-band integral-field
spectroscopy of W33A and its inner reflection nebula. In our data we make the
first detections of a rotationally-flattened outer envelope and fast bi-polar
jet of a massive YSO at near-infrared wavelengths. The predominant spectral
features observed are Br-gamma, H_2, and a combination of emission and
absorption from CO gas. We perform a 3-D spectro-astrometric analysis of the
line emission, the first study of its kind. We find that the object's Br-gamma
emission reveals evidence for a fast bi-polar jet on sub-milliarcsecond scales,
which is aligned with the larger-scale outflow. The hybrid CO features can be
explained as a combination of hot CO emission arising in a disk close to the
central star, while cold CO absorption originates in the cooler outer envelope.
Kinematic analysis of these features reveals that both structures are rotating,
and consistent with being aligned perpendicularly to both the ionised jet and
the large-scale outflow. Assuming Keplerian rotation, we find that the
circumstellar disk orbits a central mass of >10Msun, while the outer envelope
encloses a mass of ~15Msun. Our results suggest a scenario of a central star
accreting material from a circumstellar disk at the centre of a cool extended
rotating torus, while driving a fast bi-polar wind. These results therefore
provide strong supporting evidence for the hypothesis that the formation
mechanism for high-mass stars is qualitatively similar to that of low-mass
stars.Comment: 13 pages, 18 figs. Accepted for publication in MNRA
Una mirada emic a las actitudes: percepción de las personas con síndrome de down an emic view toward attitudes: perceptions of individuals with down syndrome
Starting from the premise that attitudes influence behavior of those who expressed such attitudes, as well as from the attitudinal referents, in this study we present the results obtained after assessing the perceptions of 15 individuals with Down syndrome by means of in depth interviews. The objective was to determine the perceptions of people with Down syndrome toward themselves and their disability. We expected that respondents perceived both positive and negative attitudes. The interviews were transcribed and the results of the coding of the 147 selected textual fragments revealed the existence two major factors. On the one hand, those that denote unfavorable attitudes and relate to shame, rejection, understanding the Down syndrome as a disease, overprotection or consider that they are all friendly and loving. It also includes comments to some remaining challenges and its association with the need to eliminate stereotypes and overprotection. Concerning positive attitudes, they relate to perceived improvements in the recognition of their rights, inclusion in different life, social and employment domains. There are also improvements regarding equal treatment, acceptance and respect. Finally, guidelines for improving the inclusion of this group are suggested.A partir de la premisa de que las actitudes influyen en la conducta de quien manifiesta dichas actitudes, pero también en el referente actitudinal o receptor de las mismas, en el presente estudio presentamos los resultados obtenidos tras evaluar las percepciones de 15 personas con síndrome de Down, a quienes hemos realizado una entrevista en profundidad. El objetivo ha sido conocer la percepción que tienen las personas con Síndrome de Down de ellos mismos y de su discapacidad. Esperábamos encontrar que los informantes percibían tanto actitudes positivas como negativas. Las entrevistas fueron transcritas y los resultados de la codificación de los 147 fragmentos textuales seleccionados pusieron de manifiesto la existencia dos grandes factores. Por un lado, todos aquellos que denotan actitudes desfavorables y que como sucediera anteriormente, se relacionan con la lástima, el rechazo, la consideración del síndrome como una enfermedad, la sobreprotección o considerar que todos son simpáticos y cariñosos. Se incluye también la mención a ciertos retos pendientes y su asociación con la necesidad de eliminar estos estereotipos y la sobreprotección asociada. En cuanto al factor relativo a actitudes favorables, se relaciona con mejoras percibidas en el reconocimiento de sus derechos, la inclusión diferentes áreas de la vida, social y laboral. También en lo relativo a la igualdad de trato, aceptación y respeto. Finalmente, se ofrecen pautas para la mejora de la inclusión de este colectivo
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