Frequency Spectra
Mostrando 1-12 de 267 artigos, teses e dissertações.
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1. Analysis of the Dynamic Stability of Ball-End Milling of AISI D6 Hardened Steel
AISI D6 hardened steel is a difficult to cut material that it is employed in mould and die manufacturing where long ball-end mills are frequently required to machine deep cavities. This condition can lead to excessive vibration between tool and workpiece resulting in a poor surface finishing and reduced tool life. This work analyses the dynamic stability of
Mat. Res.. Publicado em: 02/12/2019
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2. Dynamic Arrays Based on Magnetically Controlled Particles: Synthesis and Application
Growth mechanisms of dynamic granular arrays based on magnetically controlled particles are presented. Method of the external rotating magnetic field (ERMF), based on a dipole interaction of magnetic spherical Fe3O4 particles in highly ordered volume arrays is proposed and a design for its practical implementation is developed. The magnetic assembly can resu
Mat. Res.. Publicado em: 19/08/2019
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3. Construction and measurement of an electromagnetic noise generator based on an automotive coil
This article covers the design of an electromagnetic noise generator which uses an automotive coil as the main component. A short theoretical analysis covers the generation of high voltage pulsed current from the available DC source originated from the battery. An electronic dimmer, a circuit used to control the brightness of a light, by controlling the effe
Rev. Bras. Ensino Fís.. Publicado em: 22/06/2017
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4. Synthesis, Characterization and Dielectric Properties of New 5-(4-Hydroxyphenyl)- 10,15,20-tri-4-[2-(3-pentadecylphenoxy)ethoxy]phenyl porphyrin and Their Ni, Co and Cu Complexes
New asymmetric cardanol-based porphyrins, free-base and coordinated with Ni, Co and Cu, were synthesized and completely characterized as A3B type. Such porphyrins were obtained aiming improved solubility in polar solvents due insertion of an -OH phenolic group. Their thermal and dielectric properties were also evaluated. Changes in the synthetic route reduce
J. Braz. Chem. Soc.. Publicado em: 2017-06
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5. Oxygen Effect on Structural and Optical Properties of ZnO Thin Films Deposited by RF Magnetron Sputtering
ZnO thin films with wurtzite structure have been grown on Si (100) and glass substrates using radio frequency (rf) magnetron sputtering at room temperature. The ZnO thin films have been characterised by XRD. The (002) orientation is observed at zero Oxygen flow after the (100) developed with increasing oxygen ratio. Usually, this orientation (100) is difficu
Mat. Res.. Publicado em: 13/03/2017
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6. Non-invasive monitoring system of synchronous generator using external field
Abstract This paper presents an equipment dedicated to the monitoring of synchronous generator through the measurements of the external magnetic field time derivative. The equipment uses a methodology which can be an additional technique to those applied currently on the faults detection, mainly when monitoring the incipient faults type. Based on frequency s
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-03
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7. Investigation of Structural, Morphological, Magnetic Properties and Biomedical applications of Cu2+ Substituted Uncoated Cobalt Ferrite Nanoparticles
ABSTRACT In the present work, Cu2+ substituted cobalt ferrite (Co1-xCuxFe2O4, x = 0, 0.3, 0.5, 0.7 and 1) magnetic nanopowders were synthesized via chemical co-precipitation method. The prepared powders were investigated by various characterization methods such as X-ray diffraction analysis (XRD), scanning electron microscope analysis (SEM), vibrating sample
Braz. arch. biol. technol.. Publicado em: 23/01/2017
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8. Thermal Transformation and Characterization of Synthetic Al-Substituted Maghemites (γ-Fe2-xAlxO3)
ABSTRACT Burning is a common practice in tropical areas and related changes in mineralogy might affect the chemical and physical behavior of soils. Maghemite is a common iron oxide in soils formed from basic rocks in tropical regions. This mineral and hematite are the main pigments in these soils and exhibit high magnetization stemming from the precursor mag
Rev. Bras. Ciênc. Solo. Publicado em: 03/11/2016
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9. Effects of season, sex and age on the diet of Homonota fasciata (Squamata, Phyllodactylidae) from Monte region of Argentina
Abstract This study aimed to investigate the diet of the gecko Homonota fasciata (Duméril & Bibron, 1836) in a population from Monte of San Juan Province, Argentina, and to analyze possible temporal, sexual, and ontogenetic variations in feeding behavior. We determined the total volume, number, and occurrence frequency of each prey item and calculated the r
Iheringia, Sér. Zool.. Publicado em: 01/08/2016
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10. Biosensor Based on Cysteine Monolayer and Monoclonal Antibody for Specific Detection of Aflatoxin B1 in Rice
An electrochemical immunosensor for detection of aflatoxin B1 (AFB1) in food samples was developed. The sensor is composed by cysteine monolayer immobilized on gold electrode surface with subsequent bind to monoclonal antibody (MAb-Cys-modified electrode). The AFB1 detection was evaluated by cyclic voltammetry and impedance spectroscopy in the frequency rang
J. Braz. Chem. Soc.. Publicado em: 2016-06
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11. Propiedades eléctricas en membranas de complejos electrolitos poliméricos PVA-OH/LI2SO4/PEG400
Lithium ion conducting polymer electrolytes based on polyvinyl Alcohol (PVA-OH) complexed with salt Li2SO4 and different weight percent ratios of PEG400 plasticizer have been prepared by solution cast technique using deionized water as solvent. The thermogravimetric analysis (TGA) showed that the thermal stability of the materials depended on the plasticizer
Polímeros. Publicado em: 2014
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12. Non-linear dynamics of a hanging rope
Two-dimensional motion of a hanging rope is considered. A multibody system with elastic-dissipative joints is used for modelling of the rope. The mathematical model based on the Lagrange formalism is presented. Results of some numerical simulations are shown for the mechanical system with kinematic excitation. Basic tools are used to qualify dynamics of the
Lat. Am. j. solids struct.. Publicado em: 2013-01