Optical Sensors
Mostrando 1-12 de 95 artigos, teses e dissertações.
-
1. Prospects for Developing Low-Cost Optical Fiber Sensors for Liquid-Liquid Interface Detection
Abstract This work examines the prospects of a low-cost retroreflection optical sensor system for detection of the interface between two immiscible liquids, for applications in oil separation tanks. The sensor in its simplest configuration comprises a bare fiber optic tip, cleaved at an angle of 90º relative to the longitudinal fiber axis. The device tested
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
-
2. FASE SENSORA DE POLI(CLORETO DE VINILA) NA DETECÇÃO DE 17β-ESTRADIOL EM MEIO AQUOSO UTILIZANDO ESPECTROSCOPIA NO INFRAVERMELHO MÉDIO E QUIMIOMETRIA
In recent years, estrogens have gained notable attention among emerging pollutants, increasingly leading to the need for less laborious analytical methods. Optical sensors are a promising technology for the determination of chemical contaminants in water, acting as an alternative screening method. The aim of this work was to evaluate the performance of poly(
Quím. Nova. Publicado em: 2020-09
-
3. CORRELATIONS AMONG VEGETATION INDICES AND PEANUT TRAITS DURING DIFFERENT CROP DEVELOPMENT STAGES
ABSTRACT Active optical sensors have been widely used for the spatial and temporal monitoring of peanut culture because they are accurate, non-destructive methods for rapidly obtaining data. The objective of this study was to determine the optimal stage of crop growth for collecting sensor readings based on correlations between quality indicators. In additio
Eng. Agríc.. Publicado em: 09/09/2019
-
4. EFFECT OF HEIGHT, TILT AND TWIST ANGLES OF AN ACTIVE REFLECTANCE SENSOR ON NDVI MEASUREMENTS
ABSTRACT The application of nitrogen (N) fertilizer is complex and expensive, so its correct management has financial and environmental benefits. The use of optical proximity sensors is a promising technique. However, the movement of the agricultural machinery or of the person carrying the sensor will result in height differences and/or different tilt and tw
Eng. Agríc.. Publicado em: 09/09/2019
-
5. Monitoring structures with optical fibers: infiltration detection
ABSTRACT The use of sensors and optical fibers for monitoring structures is continuously growing. Strains, displacements, accelerations, temperatures are just a few of the monitoring possibilities. In the case of dam structures, concrete face rockfill dams constitute a type of structures where the monitoring of water infiltrations is of particular interest.
An. Acad. Bras. Ciênc.. Publicado em: 2018-04
-
6. Compensation technique for environmental and light source power variations applied in a polymer optical fiber curvature sensor for wearable devices
Abstract Introduction Polymer optical fibers (POF) are lightweight, present high elastic strain limits, fracture toughness, flexibility in bend, and are not influenced by electromagnetic fields. These characteristics enable the application of POF as curvature sensor and can overcome the limitations of the conventional technologies, especially for wearable a
Res. Biomed. Eng.. Publicado em: 05/03/2018
-
7. Synthesis and Photophysical Characterization of Proton Transfer-Based Thiourea Derivatives: Potential Application as Colorimetric Naked-Eye Chemosensor for Fluoride Detection in Solution
Two new thiourea derivatives were synthesized through the reaction of photoactive aminohydroxybenzazoles and p-isothiocyanate benzoic acid via nucleophilic addition reaction. The compounds were characterized using high resolution mass spectrometry with eletrospray ionization (HRMS-ESI), Fourier transform infrared (FTIR), 13C and 1H nuclear magnetic resonance
J. Braz. Chem. Soc.. Publicado em: 2017-09
-
8. Remote sensing of the chlorophyll-a based on OLI/Landsat-8 and MSI/Sentinel-2A (Barra Bonita reservoir, Brazil)
ABSTRACT In this present research, we assessed the performance of band algorithms in estimating chlorophyll-a (Chl-a) concentration based on bands of two new sensors: Operational Land Imager onboard Landsat-8 satellite (OLI/Landsat-8), and MultiSpectral Instrument onboard Sentinel-2A (MSI/Sentinel-2A). Band combinations designed for Thematic Mapper onboard L
An. Acad. Bras. Ciênc.. Publicado em: 31/08/2017
-
9. Influence of temperature on the refractive index sensitivities of fiber Bragg gratings refractometers
Abstract Effect of cross-sensitivity between temperature and refractive index (RI) was studied using an optical sensor based on Bragg grating inscribed in an etched multi-mode fiber (MMF). RI sensitivities of different modes were used to obtain a linear response and temperature dependence in water:glycerin solutions. Results pointed out that the absolute ave
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-04
-
10. Classification of Flying Insects with high performance using improved DTW algorithm based on hidden Markov model
ABSTRACT Insects play significant role in the human life. And insects pollinate major food crops consumed in the world. Insect pests consume and destroy major crops in the world. Hence to have control over the disease and pests, researches are going on in the area of entomology using chemical, biological and mechanical approaches. The data relevant to the fl
Braz. arch. biol. technol.. Publicado em: 23/01/2017
-
11. Thermal Monitoring of Photovoltaic module using Optical Fiber Sensors
Abstract This paper proposes the use of fiber Bragg gratings (FBG) in thermal monitoring of photovoltaic (PV) modules. Results acquired from FBG sensors were compared with two commonly used temperature sensing techniques in PV modules: PT100 sensors and infrared cameras. The experiments were performed using a PV module in actual operating conditions (varying
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2016-12
-
12. Recovery of α-Al2O3 from Ionizing Radiation Dosimetric Sensors
Corundum, sapphire or α-Al2O3 is an important technological material in many optical and electronic applications such as solid-state lasers, optical windows and, more recently, as a radiation detector. Landauer (Glenwood, IL, USA) accumulated large number of archived and stored Luxel™ dosemeters composed of Al2O3:C, which were subjected to a recovery proc
Mat. Res.. Publicado em: 2015-02