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| Deen, M.; Wielandt, E.; Stutzmann, Eleonore; Crawford, W.; Barruol, G.; Sigloch, K.. |
| The Earth's hum is the permanent free oscillations of the Earth recorded in the absence of earthquakes, at periods above 30 seconds. We present the first observations of its fundamental spheroidal eigenmodes on broadband Ocean Bottom Seismometers (OBS) in the Indian Ocean. At the ocean bottom, the effects of ocean infragravity waves (compliance) and seafloor currents (tilt) overshadow the hum. In our experiment, data are also affected by electronic glitches. We remove these signals from the seismic trace by subtracting average glitch signals; performing a linear regression and using frequency-dependent response functions between pressure, horizontal and vertical seismic components. This reduces the long period noise on the OBS to the level of a good land... |
| Tipo: Text |
Palavras-chave: Hum; Noise; Continuous oscillations; Broadband ocean bottom seismology; Surface waves; Glitch. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00407/51841/52446.pdf |
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| De Ruiter, Stacy; Boyd, Ian L.; Claridge, Diane E.; Clark, Christopher W.; Gagnon, Chuck; Southall, Brandon L.; Tyack, Peter L.. |
| In 2007 and 2008, controlled exposure experiments were performed in the Bahamas to study behavioral responses to simulated mid-frequency active sonar (MFA) by three groups of odontocetes: false killer whales, Pseudorca crassidens; short-finned pilot whales, Globicephala macrorhynchus; and melon-headed whales, Peponocephala electra. An individual in each group was tagged with a Dtag to record acoustic and movement data. During exposures, some individuals produced whistles that seemed similar to the experimental MFA stimulus. Statistical tests were thus applied to investigate whistle-MFA similarity and the relationship between whistle production rate and MFA reception time. For the false killer whale group, overall whistle rate and production rate of the... |
| Tipo: Text |
Palavras-chave: Noise; Sonar; Mid-frequency sonar; Whistle; Behavioral effects; Sound production; Pseudorca crassidens; Globicephala macrorhynchus; Peponocephala electra; False killer whale; Pilot whale; Melon-headed whale. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00138/24974/23185.pdf |
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| Freitas,Leticia Cibele da Silva Ramos; Campos,Alessandro Torres; Yanagi Junior,Tadayuki; Schiassi,Leonardo; Andrade,Rafaella Resende. |
| ABSTRACT Because of the importance of the ambiance in swine facilities, this study aimed to evaluate the air quality, the sound pressure level, and the thermal environment of two distinct swine nursery styles. A completely randomized block design with a split-plot arrangement was used, in which the main plots were composed of the nurseries and the external environment; the subplots were the hours; and the replications were the collection days. Air temperature data (ºC), relative humidity (%), and black globe humidity index (BGHI) data were collected throughout the day at 10-min intervals, with means compared by Tukey’s test at 0.05 probability level. Instantaneous concentrations of ammonia (ppm), carbon dioxide (ppm), and sound pressure levels (dB(C)) were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Rural buildings; Piglets; Gases; Noise; Thermal ambience. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902018000200211 |
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| Farzad Jalilian tabar; Hekmat Rabbani; Agricultural Machinery Department, Razi University of Kermanshah, Iran; Alinejat Lorestani; Agricultural Machinery Department, Razi University of Kermanshah, Iran; Payam Javadikia; Agricultural Machinery Department, Razi University of Kermanshah, Iran; Rashid Gholami; Agricultural Machinery Department, Razi University of Kermanshah, Iran;. |
| Tractors have been used for transportation on roads by many farmers in addition to use in the field operations. MF285 tractor is the popular kind of tractor in Iran (about 30% of all tractors) and almost this tractor has been used without cabin. Despite the problems caused by noise from the tractors and all its adverse effects on users and observers, no comprehensive research has been done on them. The result of this research indicate that the noise level of MF285 tractor, in 2250 r/min engine speed, will be 90 dB(A) which in comparison with the standard value, 85 dB(A), is dangerous for operator’s ears. The test site was prepared according to the international standards. The noise emitted by tractor in three gears (2, 3 and 4) and three speeds (1,500,... |
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Palavras-chave: Noise; Tractor; Sound pressure level; Ergonomics. |
| Ano: 2012 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/2096 |
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