Case history: The use of narrow‐band frequency analysis to accurately identify multiple, stationary environmental noise sources

2005 ◽  
Vol 118 (3) ◽  
pp. 1921-1921
Author(s):  
Chris R. Depies
Keyword(s):  
Frequency Analysis ◽  
Case History ◽  
Narrow Band ◽  
Environmental Noise ◽  
Noise Sources ◽  
Band Frequency

Spinning Frame Noise Sources

1976 ◽  
Vol 98 (3) ◽  
pp. 840-844 ◽  
Author(s):  
N. D. Stewart ◽  
P. D. Emerson ◽  
J. R. Bailey
Keyword(s):  
Noise Reduction ◽  
Frequency Analysis ◽  
Textile Industry ◽  
Narrow Band ◽  
Vacuum System ◽  
Relative Importance ◽  
Noise Sources ◽  
Band Frequency ◽  
Reduction Program

As part of a Coordinated Textile Industry Noise Reduction Program, a study of the sources of spinning frame noise has been conducted. Techniques of source modification and narrow-band frequency analysis were used. Several machines were studied. Major noise sources were found to be the ring-traveler and spindle-bobbin systems. Other sources identified were the drive cylinder, drive tapes, idler pulleys, vacuum system, and gears. Relative importance of the sources and differences among machines is discussed. Suggestions are offered for ways to reduce noise from some of the sources. Work is continuing to evaluate and develop the most feasible methods of spinning frame noise reduction.

Coordinated diameter oscillations at arteriolar bifurcations in skeletal muscle

1987 ◽  
Vol 253 (3) ◽  
pp. H568-H573 ◽  
Author(s):  
J. U. Meyer ◽  
L. Lindbom ◽  
M. Intaglietta
Keyword(s):  
Skeletal Muscle ◽  
Fundamental Frequency ◽  
Narrow Band ◽  
Photometric System ◽  
Band Frequency ◽  
Skeletal Muscle Microcirculation

The spontaneous rhythmical luminal changes (vasomotion) at bifurcations in the microvasculature of the rabbit tenuissimus muscle were investigated by means of a microscope video photometric system. Video scenes, containing two terminal arterioles originating from one transverse arteriole, showed that adjacent terminal arterioles constricted synchronously in 26 out of 31 contraction cycles. The onset of 60 constrictions in the parent transverse vessels was synchronized with the activity in terminal arterioles in 75% of the cycles and delayed in 25%. Vasomotion in the parent transverse vessels was notably smaller than in the terminal vessels. All the terminal arterioles in the different animals oscillated at the fundamental frequency of 18.9 +/- 3.5 cycles/min. We conclude that in the skeletal muscle microcirculation 1) coordinated spontaneous diameter oscillations occur in arterioles that are in proximity, 2) diameter changes are most pronounced in the terminal arterioles, and 3) coordinated vasomotion in this tissue exhibits a characteristic narrow band frequency. The presence of a microvascular pacemaker is hypothesized.

scholarly journals Level and Noise Sources in the Neonatal Intensive Care Unit of a Reference Hospital

2020 ◽  
Vol 38 (3) ◽  
Author(s):  
Alma Damaris Hernández-Salazar ◽  
Josefina Gallegos-Martínez ◽  
Jaime Reyes-Hernández
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Neonatal Intensive Care Unit ◽  
Neonatal Intensive Care ◽  
Environmental Noise ◽  
Sound Level ◽  
Noise Sources ◽  
Cross Sectional ◽  
Reference Hospital ◽  
And Shifts

Objective. Determine the level of environmental and periauricular noise in preterm babies and identify the sources generating noise in the Neonatal Intensive Care Unit -NICU- of a reference hospital in San Luis Potosí, Mexico. Methods. Cross-sectional and analytic study of the measurement of the level of environmental noise in five critical areas of the NICU, according with the method of measurement of noise from fixed sources by the Mexican Official Norm and periauricular at 20 cm from the preterm patient’s pinna. The measurements were carried out during three representative days of a week,morning, evening and nocturnal shifts. A STEREN 400 sound level meter was used with 30 to 130 dB range of measurement and a rate of 0.5 s. Results. The average level of periauricular noise (64.5±1.91dB) was higher than the environmental noise (63.3±1.74 dB) during the days and shifts evaluated. The principal noise sources were activities carried out by the staff, like the nursing change of shift and conversations by the staff, which raised the level continuously or intermittently, operation of vital support equipment (alarms) and incidences (clashing of baby bottles and moving furnishings) producedsudden rises of noise. Conclusions. Environmental and periauricular noise in NICU exceeds by two and almost three times the 45 dB during the day and 35 dB at night from the norm in hospitals. It is necessary to implement permanent noise reduction programs to prevent sequelae in the preterm infant and professional burnout in the nursing staff.

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