385 research outputs found
Corrigendum to "Optical constants of ethylene glycol over an extremely wide spectral range" [Opt. Mater. 37 (2014) 36-41]
The authors would like to integrate the information contained in the printed version of the above article by providing numerical data concerning Fig. 2 of the mentioned paper. A part of these data was already reported in Table 1 of the mentioned paper in a reduced form for space reasons
Spectral optical constants of ethanol and isopropanol from ultraviolet to far infrared
Ethanol and isopropanol are fluids of common use in different branches of materials science. In particular, in the ever growing field of nanoscience, they are dispersing media for nanoparticle suspensions. The knowledge of optical constants of these fluids is required for the characterization of optical properties of nanoparticles, besides providing insights into fundamental properties of fluids themselves. In this work, we calculated the real refractive index n of ethanol and isopropanol applying the Kramers-Kronig theory to the experimentally obtained k spectrum over an extremely wide spectral range, from 181 to ∼ 54000 cm-1
Optic Nerve Degeneration and Reduced Contrast Sensitivity Due to Folic Acid Deficiency: A Behavioral and Electrophysiological Study in Rhesus Monkeys
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MAX phases as candidates for Concentrated Solar Power receivers
New generation concentrated solar power (CSP) plants require new solar
receiver materials with selective optical properties and excellent corrosion
resistance against molten salts. MAX phases are promising materials for CSP
applications due to their optical properties and resistance to extreme
environments. Herein, we report a solar absorptance above or equal to 0.5 and a
thermal emittance of 0.17-0.31 between 600 and 1500 K for Cr2AlC, Ti2AlC, and
Ti3AlC2. These compositions were also exposed to solar salt corrosion at 600
{\deg}C for up to 4 weeks. Cr2AlC exhibited a superior corrosion resistance due
to the formation of a protective nanometric layer.Comment: 19 pages, 5 figures, 1 tabl
Factores de riesgo asociados a la formación de UPP en pacientes postrados del Hospital Daniel Alcides Carrión, 2021
La presente investigación tuvo como objetivo principal determinar los factores de
riesgo que se asocian a la formación de UPP, en pacientes postrados del Hospital
Nacional Daniel Alcides Carrión, 2021. La metodología empleada fue de tipo
descriptiva, diseño no experimental y enfoque cuantitativo. La muestra estuvo
conformada por 30 pacientes entre hombres y mujeres de edad adulta y adulta
mayor. Las técnicas para recolectar los datos se establecieron a través de la
entrevista y la observación; mientras que para los instrumentos se basaron en las
historias clínicas de los pacientes del Hospital Nacional Daniel Alcides Carrión y la
lista de cotejo de los factores intrínsecos y extrínsecos. Se llegó a concluir que el
70% de la población encuestada asocia la formación de UPP con los factores de
riesgo en un modo presente y un 30% de los mismos tiene un riesgo de tipo
ausente. Palabras Claves: Factores de riesgo, factores intrínsecos, factores
extrínsecos, intervención de la enfermería, úlceras por presión
Implementation and Test of a LED-Based Lamp for a Lighthouse
A novel sustainable source was developed for an existing Italian lighthouse, exploiting the light emitting diode (LED) technology and the norms evolution. The research work started with the optical design of the device, while this work concerns the realization, installation, and test of the new LED lamp. The lamp recombines multiple separated LEDs, realizing a quasipunctual localized source. After installation in the lighthouse, specific photometric tests verified that the proposed power-saving source satisfied the illumination requirements of the marine signaling norms. The advantages of the LED-based lamp are reduced energy consumption, enhanced efficiency, longer life, decreased faults, slower aging, and lower maintenance costs. The obtained LED signalling device is more durable and reliable. In the future the application of these power-saving long-life sources could be extended to other maritime signaling devices or to other traffic signs
Synthesis and characterization of gold/water nanofluids suitable for thermal applications produced by femtosecond laser radiation
A laser-based “green” synthesis of nanoparticles (NPs) was used to manufacture gold
NPs in water. The light source is a Ti:Sapphire laser with 30 fs FWHM pulses, 800 nm mean
wavelength, and 1 kHz repetition rate. The method involves two stages: (1) pulsed laser ablation
in liquids and (2) photo-fragmentation (PF). Highly pure and well-dispersed NPs with a diameter
of 18.5 nm that can be stored at room temperature without showing any agglomeration over a
period of at least 3 months were produced without the need to use any stabilizer. Transmittance
spectra, extinction coefficient, NPs agglomeration dynamics, and thermal conductivity of the
nanofluids obtained were analyzed before and after being submitted to thermal cycling and compared
to those obtained for commercial gold/water suspensions. Optical properties have also
been investigated, showing no substantial differences for thermal applications between NPs produced
by the laser ablation and PF technique and commercial NPs. Therefore, nanofluids produced
by this technique can be used in thermal applications, which are foreseen for conventional
nanofluids, e.g., heat transfer enhancement and solar radiation direct absorption, but offering the
opportunity to produce them in situ in almost any kind of fluid without the production of any
chemical waste.This work was partially funded by the Generalitat Valenciana through the programme
PROMETEO–2012–021, and by the Universitat Jaume I through the projects P1·1B2013–43
and P1·1B2013–53. Financial support from the Spanish Ministry of Science FIS2013–
40666–P is also acknowledged. The authors are also very grateful to the Servicios Centrales
de Instrumentación Científica (SCIC) of the Universitat Jaume I for the use of the femtosecond
laser. R. Torres-Mendieta gratefully acknowledges the Generalitat Valenciana support from the
Santiago Grisolia scholarship GRISOLIA/2013/015. The Italian bank foundation “Fondazione
Ente Cassa di Risparmio di Firenze” is gratefully acknowledged for providing the grant for M.
Meucci within the framework of the “SOLE” and “SOLE-2” projects (pratiche n. 2013.0726 and
2014.0711). Thanks are due to Mr. Mauro Pucci and Mr. Massimo D’Uva from CNR-INO for
technical assistance
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