Sine Wave
Mostrando 13-24 de 62 artigos, teses e dissertações.
-
13. Metodologia de projeto de suspensão pantografica para corte de base de cana-de-açucar / Project methodology of pantographic suspension for sugar cane base cuter
In spite of been the world leader in sugar-cane production, Brazil have low indexes of harvester mechanization of sugar-cane. The sugar-cane harvesting involves five simple operations, that are the cut of the stems in the base and in the top, feeding of the stems for the interior of the harvester, remove the leaves and the cutting the stem in billets which i
Publicado em: 2008
-
14. Mesopic radial frequency contrast sensitivity function for young and older adults
The objective of the present study was to determine contrast sensitivity curves of concentric circular patterns with radial frequencies of 0.25, 0.5, 1.0, 2.0, and 4.0 cycles per degree in young and older adult volunteers. These parameters were also compared with sensitivity contrasts for sine-wave gratings. All participants had normal acuity vision and were
Brazilian Journal of Medical and Biological Research. Publicado em: 2006-06
-
15. Radial frequency stimuli and sine-wave gratings seem to be processed by distinct contrast brain mechanisms
An assumption commonly made in the study of visual perception is that the lower the contrast threshold for a given stimulus, the more sensitive and selective will be the mechanism that processes it. On the basis of this consideration, we investigated contrast thresholds for two classes of stimuli: sine-wave gratings and radial frequency stimuli (i.e., j0 tar
Brazilian Journal of Medical and Biological Research. Publicado em: 2005-03
-
16. Sistema de monitoramento e metodologia de estimativa dos tempos de operação do disjuntor. / Monitoring system and methodology to estimation of circuit breaker operation times.
The present work addresses the development of a circuit breaker monitoring system so as to collect information for predictive maintenance. The characteristics of the variables that are monitored through certain sensors linked to the circuit breaker, its acquisition and the treatment of the information, are analyzed. A prototype was developed and installed at
Publicado em: 2005
-
17. Comparison of angular frequency contrast sensitivity in young and older adults
The aim of the present study was to measure contrast sensitivity curves for angular frequencies in the range between 2 and 96 cycles/360º in older human adult volunteers and to compare these measurements with the more usual contrast sensitivity functions for sine-wave gratings. All subjects were free of identifiable ocular disease and had normal acuity. We
Brazilian Journal of Medical and Biological Research. Publicado em: 2004-03
-
18. Estudo e Aperfeiçoamento do Vocoder de Transformada Senoidal
The basic sinusoidal analysis/synthesis system is presented and recent parameters codification techniques are studied. In addition, new methods for improving the speech quality of Sinusoidal Transform Vocoders at 2,4 and 4,8 Kbps are presented. One of them is a refinement in the pitch estimation, since pitch accuracy is essential for the efficiency of the ha
Publicado em: 2004
-
19. ESTIMAÇÃO EM TEMPO REAL DE SENÓIDES HARMÔNICAS POR DECOMPOSIÇÃO EM SUB-BANDAS / REAL TIME HARMONIC SINE WAVE ESTIMATION BY SUB-BAND DECOMPOSITION
A medição da qualidade de energia é um aspecto cada vez mais importante com o avanço tecnológico. Um destes aspectos é a estimação dos harmônicos em sinais de potência. Este trabalho, apresenta um algoritmo para obter, simultaneamente, os valores reais de freqüência, amplitude e fase de cada componente do sinal, baseados em valores distorcidos or
Publicado em: 1999
-
20. Avaliação das resistencias a fratura e a fadiga de tres sistemas de ceramica dental
The aims of this paper was to investigate the influencia of fatigue, on the fracture strength of In ceram, OPC¿ and IPS Empress in both wet and dry environments, luted with zinc phosphate and glass ionomer cements. Fifty two crowns shapes with 8mm in diameter and 8.5mm height were fabricated for each ceramic system. After glazing, the crown shapes were ceme
Publicado em: 1998
-
21. Estudo da resposta dinamica de uma locomotiva a excitações devidas a irregularidades da via
This work presents a theoretical analysis of the dynamic behavior of locomotives on straight tracks. A mathematical model with thirty-nine degrees of freedom is developed and eingenvalues and eigenvectors, natural frequencies and dominant motions are determined. The excitation forces include vertical and lateral directions track irregularities, which are rep
Publicado em: 1987
-
22. The pattern of breathing in man in response to sine waves of alveolar carbon dioxide and hypoxia.
Sine waves of alveolar CO2 at constant high alveolar O2, and sine waves of alveolar hypoxia (1/(PA, O2 -C) where C congruent to 32 torr) at constant alveolar CO2 have been administered to three subjects in each case. Six different periods of the sine waves were studied, ranging between 900 and 30 s for the CO2 sine waves and 300 and 20 s for the hypoxic sine
-
23. Effects of pulse frequency on single-unit baroreceptor activity during sine-wave and natural pulses in dogs.
1. Previous studies using sine-wave pulses have shown that changes in pulse frequency do not alter single-unit activity per unit time. Since baroreceptor activity is phasic with most of the activity occurring in systole, we reasoned that the lack of effect of pulse frequency is due to the associated reciprocal change in duration of systole with sine-wave pul
-
24. Nonlinear wave equations and constrained harmonic motion
The study of the Korteweg-deVries, nonlinear Schrödinger, Sine-Gordon, and Toda lattice equations is simply the study of constrained oscillators. This is likely to be true for any nonlinear wave equation associated with a second-order linear problem.