Authors:C. Cano-Molina, A. López-Fernández, N. Díaz-González, R. González-Barrio, N. Baenas, M.J. Periago, and F.J. García-Alonso
) and/or light-emittingdiodes (LED) have been shown to enhance carotenoid levels ( Bravo et al., 2012 ; Nájera et al., 2018 ; Panjai et al., 2017 , 2019 ; Dyshlyuk et al., 2020 ). The aim of the present study was to evaluate the effect of combined
In the photomicrocalorimetric module designed by Johansson and Wadsö for a commercial Thermometric TAM heat conduction batch
microcalorimeter, the incident light from an external xenon lamp was divided by a beam splitter and directed to the two vessels
of the differential system by light guides ideally to give zero heat flow. In practice this proved difficult and so to improve
the balance between the vessels in terms of the incident light heat output as well as potentially to give more versatility
regarding the choice of wavelengths, the xenon lamp-based system was replaced in the first stage by a pair of cold white LEDs
embedded directly in the test and reference vessels. The LEDs had independent electrical circuits to achieve the balance by
manual adjustment. As a second stage, the test vessel was equipped with PTFE tubing for changing the liquid phase in it while
it was in the middle thermal equilibrium position. This improved the reproducibility of the results.
A new method for the determination of the equivalent dose (ED) in minerals has been developed, based on the unstable part of luminescence which fades away at ambient temperatures. Optical stimulated luminescence employing green light emitting diodes is used in two cases; a reference quartz sample and an archaeological ceramic. In both instances the obtained (ED) with the new technique provides a satisfactory agreement within the expected errors.
Authors:I. Liritzis, R. Galloway, and P. Theocaris
Two archeological ceramic sherds in a single quartz aliquot form have been dated success-fully for the first time, by the newly developed method of optical stimulated luminescence (OSL) with green light-emitting diodes (LED). Comparison with the conventional thermoluminescence (TL) method provided ages of the same order of magnitude. The ceramics come from two recently excavated sites at Hellenikon and Ligourio in Argolid, Peloponnese, Greece. One sherd dates from the end of 4th millenium B.C., while the other is classified around 7th c. B.C.. The new method of nuclear dating is described in the paper and appropriately evaluated.
Authors:S. X. S. Costa, M. R. Galvão, D. P. Jacomassi, M. I. B. Bernardi, A. C. Hernandes, A. N. de Souza Rastelli, and M. F. Andrade
polymerization, causing material hardening [ 7 – 9 ]. This light can be emitted by light-curing units (LCUs), such as conventional quartz tungsten halogen (QTH), xenon plasma arc (PAC), argon laser and light-emitting-diodes (LEDs) [ 10 ].
LED LCUs were
(Light-EmittingDiode) sectors have emerged quickly in mid-2005 (Mathews et al. 2011 ; Jang et al. 2009 ). Along with the semiconductor sector being well-developed in Taiwan, the accumulated resources in terms of manpower, capital, and technology have
The role of light-emitting diode lamps and radio frequency lighting controls is to reduce the energy consumption. The increase of lighting network complexity determines the increase of EMC noise emission. Being familiar with measurement systems is important for making correct measurement and for understanding the results of the measurement. Correct interpretation of measurement results is the first step in choosing the best suppression method. The suppression method depends on the common mode and the differential mode of noise type and on the frequency of signal noise.
Authors:Zine Eddine Hamami, Laurent Vanoye, Pascal Fongarland, Claude de Bellefon, and Alain Favre-Reguillon
An efficient and metal-free method for the oxidation of aldehydes to the corresponding carboxylic acids has been developed. In a simple continuous-flow photochemical reactor, the use of camphorquinone (CQ) irradiated with a white light-emitting diode (LED) source enhanced the autoxidation of aldehydes. Under 5 bar of oxygen, visible light, and 0.3 mol% of CQ, the rate of oxidation was increased from 6 times with 2-ethylhexanal to 30 times for n-nonanal. The large interfacial area generated by a segmented flow apparatus associated with radicals formed by photooxidation of CQ ensures metal-free high throughput of carboxylic acids under safe conditions.
Authors:Jorge Guzmán Mar, Leticia López Martínez, Pedro López de Alba, Nancy Ornelas Soto, and Víctor Cerdà Martín
A multisyringe flow injection analysis method for the determination of uranium in water samples was developed. The methodology
was based on the complexation reaction of uranium with arsenazo (III) at pH 2.0. Uranium concentrations were spectrophotometrically
detected at 649 nm using a light emitting diode. Under the optimized conditions, a linear dynamic range from 0.1 to 4.0 μg mL−1, a 3σ detection limit of 0.04 μg mL−1, and a 10σ quantification limit of 0.10 μg mL−1 were obtained. The reproducibility (%) at 0.5, 2.5, and 4.0 μg mL−1 was 2.5, 0.9, and 0.6%, respectively (n = 10). The interference effect of some ions was tested. The proposed method was successfully applied to the determination
of uranium in water samples.