Search results for "detector"
showing 10 items of 3491 documents
A chromatochemometric approach for evaluating and selecting the perfume maceration time.
2010
Abstract A chemometric treatment of the data obtained by gas chromatography (GC) with flame ionization detector (FID) has been proposed to study the maceration time involved in perfumes manufacture with the final purpose of reducing this time but preserving the organoleptic characteristics of the perfume that is being elaborated. In this sense, GC–FID chromatograms were used as a fingerprint of perfume samples subjected to different maceration times, and data were treated by linear discriminant analysis (LDA), by comparing to a set of samples known to be macerated or not, which were used as calibration objects. The GC–FID methodology combined with the treatment of data by LDA has been appli…
Phase boundary dynamics of bubble flow in a thick liquid metal layer under an applied magnetic field
2020
Dynamic neutron radiography is used to observe the effect of a transverse magnetic field on argon bubbles rising through a thick layer of liquid gallium without interactions with the container walls.
Effect of laser radiation upon heat and mass transfer in two-component elastic semitransparent layer
2004
Abstract In present paper the effect of the correlation between spectral radiative characteristics of different lasers and absorptive characteristics of laser irradiated two-component elastic semitransparent material upon coupled thermal, diffusive and elastic processes in the layer is examined. Irradiated material is supposed to consist of elastic matrix and gaseous admixture. Investigations are carried out within the model applied early to the study of mentioned coupled processes in the layer subjected to thermal infrared radiation. Calculations were carried out for four different infrared lasers. Peculiarities of heat and admixture mass transfer caused by laser irradiation are establishe…
Electronic Design for a Bleeding Detector to be Used in Intraoperative Radiotherapy Applications
2021
An electronic design for a bleeding detector used with mobile linac during intraoperative radiotherapy (IORT) is presented. It consists on a readout circuit based on a De Sauty Bridge and a wireless power supply using a supercapacitor. The goal is the measurement of the height of fluid present in the applicator in order to avoid a misadministration dose during the irradiation process. A minimum measurement height of 5 mm is required by clinic to be confident with the selected radiation dose. The measurement circuit uses a capacitive sensor which detects variations lower than 0.1 pF. The readout circuit converts dynamic capacitance variation from the bleeding detector into an analog voltage …
Internal photoemission in solar blind AlGaN Schottky barrier photodiodes
2005
We have analyzed the photoresponse of solar blind AlGaN Schottky barrier photodiodes below the alloy band gap energy, in the 3.5-4.5 eV range, and we show that it is dominated by internal photoemission. The n-type Schottky barrier height is shown to increase linearly with the band gap energy of the AlGaN alloy. The amplitude of the internal photoemission signal is about 20 times smaller than the value given by the Fowler theory based on a free electron model. We explain this result by taking into account the interband transitions and the ballistic transport of photoexcited electrons in the metal. This low value of internal photoemission allows us to achieve a spectral rejection ratio betwee…
Drift velocity of free electrons in liquid argon
1999
Abstract A measurement of the drift velocity of free electrons in liquid argon has been performed. Free electrons have been produced by photoelectric effect using laser light in a so-called “laser chamber”. The results on the drift velocity vd are given as a function of the electric field strength in the range 0.5 kV / cm ⩽| E |⩽12.6 kV / cm and the temperature in the range 87 K ⩽T⩽94 K . A global parametrization of v d (| E |,T) has been fitted to the data. A temperature dependence of the electron drift velocity is observed, with a mean value of Δ v d /( Δ T v d )=(−1.72±0.08)%/ K in the range of 87–94 K.
Eddy current imaging with an atomic radio-frequency magnetometer
2016
We use a radio-frequency $^{85}$Rb alkali-vapor cell magnetometer based on a paraffin-coated cell with long spin-coherence time and a small, low-inductance driving coil to create highly resolved conductivity maps of different objects. We resolve sub-mm features in conductive objects, we characterize the frequency response of our technique, and by operating at frequencies up to 250 kHz we are able to discriminate between differently conductive materials based on the induced response. The method is suited to cover a wide range of driving frequencies and can potentially be used for detecting non-metallic objects with low DC conductivity.
A chemical approach for the reduction of beauvericin in a solution model and in food systems.
2014
Abstract Beauvericin (BEA) is a bioactive compound produced by the secondary metabolism of several Fusarium strains with a strong antibacterial, antifungal, and insecticidal activities. This study evaluated the reduction of BEA added at 25 mg/kg in phosphate buffer saline (PBS) solutions at pH of 4, 7 and 10, or to different cereal products (kernels and flours) by the bioactive compounds phenyl isothiocyanate (PITC) and benzyl isothiocyanate (BITC). The concentration of the mycotoxin was evaluated using liquid chromatography coupled to the diode array detector (LC-DAD). In solution, BEA reduction ranged from 9% to 94% on a time-dependent fashion and lower pH levels resulted in higher BEA re…
Degradation of the minor Fusarium mycotoxin beauvericin by intracellular enzymes of Saccharomyces cerevisiae
2013
Abstract Beauvericin (BEA) is a cyclic depsipeptide with antibiotic and insecticidal effects. It was discovered for the first time from the fungus Beauveria bassiana , but more significantly, is produced by several Fusarium strains, and considered a contaminant of several cereals like corn, wheat and barley. This study investigated the degradation of BEA by intracellular raw enzymes of four strains of Saccharomyces cerevisiae , named LO9, YE5, A34, and A17. The BEA at 25 mg/kg in a model solution and in corn flour was co-incubated with the raw enzymes from the four yeast strains, respectively. The reduction of BEA was evaluated using liquid chromatography coupled to a diode array detector (…
Laboratorio de Física Nuclear y de Partículas
2018
Guiones de apoyo para el desarrollo de las actividades de laboratorio de la asignatura de Física Nuclear y de Partículas (1.5 créditos ECTS), cuyo material docente teórico está disponible en esta plataforma con el identificador http://roderic.uv.es/handle/10550/65281. Incluye tres bloques de experimentos: 1) Estadística de recuento y espectrometría beta con un detector Geiger-Mueller; 2) Espectroscopia gamma y vidas medias con un detector de NaI(Tl); 3) La cámara de niebla de difusión. Support scripts for the development of the laboratory activities of the subject of Nuclear and Particle Physics (1.5 ECTS credits), whose theoretical teaching material is available on this platform with ident…