Search results for "fourier"
showing 10 items of 1345 documents
Water detection in skin by dual-band photodiodes
2013
Purpose of this study was to develop a simple model for possibilities to detect water in skin by diffuse reflectance spectra. The model is based on comparison of diffuse reflectance spectra when illuminating water sample with LEDs of different wavelengths (1200 nm, and 1450 nm). The illumination LEDs were chosen due to water absorption differences in near-infrared spectral range. For detection, dual-band photodiode DSD2 by Thorlabs was used. Due to differences of water absorption at different wavelengths in the near-infrared spectral region, this correlation could be used for mapping of water content in skin or, in other words, determine relative moisture level in skin. Simple experimental …
Evaluation of the Complexity of Myocardial Activation During Ventricular Fibrillation. An Experimental Study
2013
A B S T R A C T Introduction and objectives: An experimental model is used to analyze the characteristics of ventricular fibrillation in situations of variable complexity, establishing relationships among the data produced by different methods for analyzing the arrhythmia. Methods: In 27 isolated rabbit heart preparations studied under the action of drugs (propranolol and KB-R7943) or physical procedures (stretching) that produce different degrees of change in the complexity of myocardial activation during ventricular fibrillation, use was made of spectral, morphological, and mapping techniques to process the recordings obtained with epicardial multielectrodes. Results: The complexity of ve…
Encapsulation of Vitamins A and E as Spray-Dried Additives for the Feed Industry
2020
Encapsulated fat-soluble powders containing vitamin A (VA) and E (VE) were prepared as a feasible additive for extruded feed products. The effect of the encapsulating agents (Capsul-CAP®
Analytical model for the long- distance tracer-transport in plants
2011
International audience; Recent investigations of long-distance transport in plants using non-invasive tracer techniques such as C radiolabeling monitored by positron emission tomography (PET) combined with magnetic resonance imaging (MRI) revealed the need of dedicated methods to allow a quantitative data analysis and comparison of such experiments. A mechanistic compartmental tracer transport model is presented, defined by a linear system of partial differential equations (PDEs). This model simplifies the complexity of axial transport and lateral exchanges in the transport pathways of plants (e.g. the phloem) by simulating transport and reversible exchange within three compartments using j…
Model, software and database for line-mixing effects in the ν3 and ν4 bands of CH4 and tests using laboratory and planetary measurements-I: N2(and ai…
2006
International audience; Absorption spectra of the infrared ν3 and ν4 bands of CH4 perturbed by N2 over large ranges of pressure and temperature have been measured in the laboratory. A theoretical approach accounting for line mixing is proposed to (successfully) model these experiments. It is similar to that of Pieroni et al. [J Chem Phys 1999;110:7717–32] and is based on state-to-state rotational cross-sections calculated with a semi-classical approach and a few empirical parameters. The latter, which enable switching from the state space to the line space, are deduced from a fit of a single room temperature spectrum of the ν3 band at 50 atm. The comparisons between numerous measured and ca…
Fabricación, caracterización, modelado y propuesta de aplicabilidad de sensores magnetorresistivos de efecto túnel para medición de potencia y sensor…
2015
En el capítulo 1 se describen los fundamentos teóricos a utilizar para los análisis y estudios a realizar más adelante, así como una breve explicación del estado de la técnica que es el estado actual de la tecnología al momento de redacción de la tesis. La introducción se divide en la tecnología magnetorresistiva, definiendo qué es y los efectos magnetorresistivos que existen así como su aplicación aeroespacial y modelización fraccional. A continuación se presenta el procesamiento digital de datos y las redes de sensores tratando un poco sobre los protocolos de comunicación formatos y aplicación de la transformada digital de Fourier. En el capítulo 2 se aborda la microfabricación de los sen…
Classification of Targets Using Statistical Features from Range FFT of mmWave FMCW Radars
2021
Radars with mmWave frequency modulated continuous wave (FMCW) technology accurately estimate the range and velocity of targets in their field of view (FoV). The targeted angle of arrival (AoA) estimation can be improved by increasing receiving antennas or by using multiple-input multiple-output (MIMO). However, obtaining target features such as target type remains challenging. In this paper, we present a novel target classification method based on machine learning and features extracted from a range fast Fourier transform (FFT) profile by using mmWave FMCW radars operating in the frequency range of 77–81 GHz. The measurements are carried out in a variety of realistic situations, including p…
Surface modification of poly(ethylene-co-acrylic acid) with amino-functionalized silica nanoparticles
2011
In this work we studied the possibility to achieve a hybrid-surface through the modification, via a facile wet chemical process, of the surface of films of poly(ethylene-co-acrylic acid) (EAA) with amino-modified silica nanoparticles. Films of EAA were preliminarily activated by the introduction of -COCl groups on their surface. Silica nanoparticles were thereafter covalently bound on the polymeric surface as confirmed by FTIR, ATR-FTIR, XPS, NMR and SEM determinations. The nanoparticles formed a multilayer on the film surface and covered almost uniformly the whole film surface. Direct measurements of superficial amino groups by titration allowed us to detect a concentration of about 18 nmo…
SEAM PUCKERING EVALUATION METHOD FOR SEWING PROCESS
2014
The paper presents an automated method for the assessment and classification of puckering defects detected during the preproduction control stage of the sewing machine or product inspection. In this respect, we have presented the possible causes and remedies of the wrinkle nonconformities. Subjective factors related to the control environment and operators during the seams evaluation can be reduced using an automated system whose operation is based on image processing. Our implementation involves spectral image analysis using Fourier transform and an unsupervised neural network, the Kohonen Map, employed to classify material specimens, the input images, into five discrete degrees of quality…
Influence of PDA Coating on the Structural, Optical and Surface Properties of ZnO Nanostructures
2020
Polydopamine (PDA) is a new biocompatible material, which has prospects in biomedical and sensor applications. Due to functional groups, it can host wide range of biomolecules. ZnO nanostructures are well known templates for optical sensors and biosensors. The combination of ZnO and PDA results in a change of optical properties of ZnO&ndash