2,640 research outputs found
Detection of Histamine Dihydrochloride at Low Concentrations Using Raman Spectroscopy Enhanced by Gold Nanostars Colloids
In this paper, we report a fast and easy method to detect histamine dihydrochloride using gold nanostars in colloidal aqueous solution as a highly active SERS platform with potential applications in biomedicine and food science. This colloid was characterized with SEM and UV–Vis spectroscopy. Also, numerical calculations were performed to estimate the plasmonic resonance and electric field amplification of the gold nanoparticles to compare the difference between nanospheres and nanostars. Finally, aqueous solutions of histamine dihydrochloride were prepared in a wide range of concentrations and the colloid was added to carry out SERS. We found SERS amplified the Raman signal of histamine by an enhancement factor of 1.0×10^7 , demonstrating the capability of the method to detect low concentrations of this amine molecule.In this paper, we report a fast and easy method to detect histamine dihydrochloride using gold nanostars in colloidal aqueous solution as a highly active SERS platform with potential applications in biomedicine and food science. This colloid was characterized with SEM and UV–Vis spectroscopy. Also, numerical calculations were performed to estimate the plasmonic resonance and electric field amplification of the gold nanoparticles to compare the difference between nanospheres and nanostars. Finally, aqueous solutions of histamine dihydrochloride were prepared in a wide range of concentrations and the colloid was added to carry out SERS. We found SERS amplified the Raman signal of histamine by an enhancement factor of 1.0×10^7 , demonstrating the capability of the method to detect low concentrations of this amine molecule
The mOxy-CaL Process: Integration of Membrane Separation, Partial Oxy-combustion and Calcium Looping for CO2 Capture
CO2 capture and storage (CCS) is considered as a key strategy in the short to medium term to mitigate global
warming. The Calcium-Looping process, based on the reversible carbonation/calcination of CaO particles, is a
promising technology for post-combustion CO2 capture because of the low cost and non-toxicity of natural CaO
precursors and the minor energy penalty on the power plant in comparison with amines capture based
technologies (4-9 % compared to 8-12 %). Another interesting process to reduce CO2 emissions in power plants
is oxy-combustion, which is based on replacing the air used for combustion by a highly concentrated (~95 %
v/v) O2 stream. This work proposes a novel process (mOxy-CaL) for post-combustion CO2 capture based on
the integration of membrane separation, partial oxy-combustion and the Calcium-Looping process. An oxygenenriched
air stream, which is obtained from air separation by using highly permeable polymeric membranes, is
used to carry out partial oxy-combustion. The flue gas exiting partial oxy-combustion shows a CO2 concentration
of ~30 % v/v (higher than 15 % v/v typical in coal power plants). After that, the flue gas is passed to the CaL
process where the CO2 reacts with CaO solids according to the carbonation reaction. Thermogravimetric
analysis show that the multicycle CaO conversion is enhanced as the CO2 concentration in the flue gas stream
is increased. Process simulations show that the mOxy-CaL process has a high CO2 capture efficiency (~95%)
with lower energy consumption per kg of CO2 avoided than previously proposed post-combustion CO2 capture
technologies. Moreover, the overall system size is significantly lower that state-of-the-art CaL systems, which
allows for an important reduction in the capital cost of the technology
Sensing Physiological Change and Mental Stress in Older Adults From Hot Weather
This study combines wearable sensors, weather data, and self-reported mood surveys to assess mental stress on older adults from heat experience. It is designed as a pilot and feasibility study in preparation for a large-scale experiment of older adults' mental wellbeing during extreme heat events. Results show that on-body temperatures from two i-Button sensors coupled with heart rate monitored from a smart watch are important indicators to evaluate individualized heat stress given a relatively uniform outdoor temperature. Furthermore, assessing their mood in their own environment demonstrates potential for understanding mental wellbeing that can change with varying time and location
Nonlinear evolution of harmonically forced perturbations on a wingtip vortex
Wingtip vortices are created by flying airplanes due to lift generation. The vortex interaction with the trailing aircraft has sparked researchers’ interest to develop an efficient technique to destroy these vortices. Different models have been used to describe the vortex dynamics and they all show that, under real flight conditions, the most unstable modes produce a very weak amplification. Another linear
instability mechanism that can produce high energy gains in short times is due to the non-normality of the system. Recently, it has been shown that these non-normal perturbations also produce this energy growth when they are excited with harmonic forcing functions.
In this study, we analyze numerically the nonlinear evolution of a spatially, pointwise and temporally forced perturbation, generated by a synthetic jet at a given radial distance from the vortex core. This type of perturbation is able to produce high energy gains in the perturbed base flow (10^3), and is also a suitable candidate for use in engineering applications. The flow field is solved for using fully nonlinear three-dimensional direct numerical simulation with a spectral multidomain penalty method model. Our
novel results show that the nonlinear effects are able to produce locally small bursts of instability that reduce the intensity of the primary vortex.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
El comunicador corporativo como sujeto político en las Pymes de Medellín
Analizar el impacto y el accionar de los egresados del programa de Comunicación y Relaciones Corporativas como sujetos políticos en las pequeñas y medianas empresas –pymes-, ubicadas en el Municipio de Medellín, en el período comprendido entre el 2002-2006, constituye un reto para los propósitos investigativos de las facultades de comunicación y, en particular, para los propósitos del grupo de investigación en comunicación y relaciones corporativas –Corpus-, adscrito a la Facultad de Comunicación de la Universidad de Medellín.Este artículo pretende explorar, desde la fundamentación teórica que sustenta el Programa de Comunicación y Relaciones Corporativas, los resultados del impacto generado por los egresados y su papel como sujetos políticos en las pequeñas y medianas empresas analizadas.Además, y dado el auge de los programas de Comunicación Social-Periodismo y de programas de Comunicación, en general, las empresas pequeñas y medianas –pymes- están demandando cada vez más egresados de comunicación a fin de que este tipo de profesional intervenga, en forma directa, sus procesos empresariales no sólo desde el ámbito de la información, sino desde los conocimientos y habilidades comunicativas como apoyo a la labor gerencial.En este artículo, que recoge algunos de los elementos más relevantes de la investigación terminada “Impacto de los egresados del programa de Comunicación y Relaciones Corporativas en las pequeñas y medianas empresas, ubicadas en el municipio de Medellín, período 2002-2006” del grupo CORPUS, pretendemos establecer el alcance real del impacto laboral, social y político de los egresados del programa de Comunicación y Relaciones Corporativas, así como reflexionar sobre la necesaria relación entre la educación y la comunicación y su potencialidad para generar aprehensiones democráticas en los actores-comunicadores que interactúan en entornos complejo
Caracterización del mapia y mapia con una adición de cal al 5%
Trabajo de InvestigaciónEn el proyecto se trabajo con un material natural, El mapia “Material pétreo de asfalto”, Se realizo la comparación con diferentes mezclas asfálticas diseñadas con el fin de cumplir un nivel de transito I según las pautas de la norma invias, Para la realización de la comparación a las mezclas se les realizo un serie de ensayo geotécnico viales para medir las características mecánicas para el posible uso en vías terciarias.Introduccion.
Antecedentes.
Justificacion.
Planteamiento y formulacion del problema.
Marcos de referencia.
Marco teórico.
Marco conceptual.
Marco legal.
Objetivos.
Alcance y Limitaciones.
Metodología
Análisis e inerpretacion de resultados.
Resumen de datos.
Conclusiones.
RecomenacionesPregradoIngeniero Civi
Effect of the axial jet on the optimal response in Batchelor vortex
En este póster se estudia la respuesta óptima del torbellino de Batchelor para distintos números de onda. Se demuestra que incluso teniendo la velocidad axial, un torbellino es capaz de tener grandes amplificaciones de energía.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Wingtip vortex in a NACA0012 airfoil and its active control
Contribución mediante sesión pósterWe conduct experiments in a towing-tank to analyse the flow patterns of wingtip vortices in a NACA 0012 airfoil. In this experimental research, we provide PIV measurements and flow visualisations. Without active control, several parameters are given experimentally as function of the Reynolds number, so we compare these data with the theoretical models of Batchelor, and Moore and Saffman together with DNS. Secondly, we analyse the effect of a continuous injection in the spanwise direction. The continuous jet has a strong influence on the wing-tip vortex formation. We explore this effect at low chord based Reynolds number ranging from 7000 up to 20000. We change the aspect ratio of the injection, R, defined as the ratio of the velocities between the jet (Uj) and free-stream (U). For R=1, we find that the jet strongly affects the wingtip vortex formation with a sudden decrement of the axial vorticity and the azimuthal velocity. This technique is a challenge and a promising tool to reduce the intensity of the vortex core.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
The Calcium-Looping (CaCO3/CaO) Process for Thermochemical Energy Storage in Concentrating Solar Power Plants
Articulo aceptado por la revista. * No publicado aún [28-06-2019]Energy storage based on thermochemical systems is gaining momentum as potential alternative to molten salts in Concentrating Solar Power (CSP) plants. This work is a detailed review about the promising integration of a CaCO3/CaO based system, the so-called Calcium-Looping (CaL) process, in CSP plants with tower technology. The CaL process relies on low cost, widely available and non-toxic natural materials (such as limestone or dolomite), which are necessary conditions for the commercial expansion of any energy storage technology at large scale. A comprehensive analysis of the advantages and challenges to be faced for the process to reach a commercial scale is carried out. The review includes a deep overview of reaction mechanisms and process integration schemes proposed in the recent literature. Enhancing the multicycle CaO conversion is a major challenge of the CaL process. Many lab-scale analyses carried out show that residual effective CaO conversion is highly dependent on the process conditions and CaO precursors used, reaching values as different as 0.07-0.82. The selection of the optimal operating conditions must be based on materials, process integration, technology and economics aspects. Global plant efficiencies over 45% (without considering solar-side losses) show the interest of the technology. Furthermore, the technological maturity and potential of the process is assessed. The direction towards which future works should be headed is discussed.Ministerio de Economia y Competitividad CTQ2014-52763-C2, CTQ2017- 83602-C2 (-1-R and -2-R)Unión Europea Horizon 2020 Grant agreement No 727348, project SOCRATCES
On the effect of low blowing ratio continuous jets on wingtip vortex characteristics
Vortices are an unavoidable effect of flight, which appear behind the wing with a bounded length. The strength of these vortices, which are extremely stable, is due to the lift force [1]. That is the reason why this phenomenon is especially relevant during take-off and landing operations. In these situations, when aircraft are departing from or arriving to the airport runways, the following aircraft might feel two counter-rotating vortices which remain long time under normal environmental conditions. Unfortunately, this huge rotation of airflow patterns always destabilizes the following aircraft. Consequently, trailing vortices have a mighty influence on the air traffic control of airport runways, and they have justified the research interest in this topic since the 1960's [2]. However, aeronautical engineers are still searching for different technological strategies to breakdown these wingtip vortices.Short-Term Postdoctoral Stay of Talent Attraction Plan of Andalucía TECH ICE. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
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