scholarly journals Decreased resting and nursing in short-finned pilot whales when exposed to louder petrol engine noise of a hybrid whale-watch vessel

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. Arranz ◽  
M. Glarou ◽  
K. R. Sprogis
Keyword(s):  
Best Practice ◽  
Low Frequency ◽  
Low Noise ◽  
Petrol Engine ◽  
Noise Emission ◽  
Behavioural Responses ◽  
Primary Driver ◽  
Pilot Whales ◽  
Vessel Noise ◽  
Electric Engine

AbstractVessel noise is a primary driver of behavioural disturbance in cetaceans, which are targeted during whale-watch activities. Despite the growing, global effort for implementing best-practice principles, to date, there are no regulations on whale-watch vessel noise levels. Here, we test the hypothesis that a whale-watch vessel with a low noise emission will not elicit short-term behavioural responses in toothed whales compared to a vessel with a louder engine. We measured behavioural responses (n = 36) of short-finned pilot whales (Globicephala macrorhynchus) to whale-watch vessel approaches (range 60 m, speed 1.5 kn). Treatment approaches with a quieter electric engine (136–140 dB) compared to the same vessel with a louder petrol engine (151–139 dB) (low-frequency–mid-frequency weighted source levels, re 1 µPa RMS @ 1 m) were examined. Focal whales were resting mother and calves in small group sizes. During petrol engine treatments, the mother’s mean resting time decreased by 29% compared to the control (GLM, p = 0.009). The mean proportion of time nursing for the calf was significantly influenced by petrol engine vessel passes, with a 81% decrease compared to the control (GLM, p = 0.01). There were no significant effects on behaviour from the quieter electric engine. Thus, to minimise disturbance on the activity budget of pilot whales, whale-watch vessels would ideally have source levels as low as possible, below 150 dB re 1 µPa RMS @ 1 m and perceived above ambient noise.

scholarly journals VARIATION OF HARMONICS EMISSION FROM MODERN LAMPS IN A POWER SUPPLY NETWORK

2019 ◽  
Vol 25 (4) ◽  
pp. 29-36
Author(s):  
RÓBERT ISTÓK
Keyword(s):  
Electromagnetic Compatibility ◽  
Low Frequency ◽  
Low Noise ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Noise Emission ◽  
Electronic Ballast ◽  
Fluorescent Lamps ◽  
The Cost

The objective of this paper is to prove the relationship between the Total Harmonics Disturbance emission of lamps network and the number of lamps. In the lighting field the LED lighting emission diode is the absolutely winner. The low power consumption and the characteristics of LED made it ideally for most of indoor and outdoor applications. The dimmability of the LEDs which is between 0% and 100% made it ideally for intelligent lighting applications. This large dimmability range could be obtained only with incandescent and halogen bulbs, compare to CFL compact fluorescent lamps where the maximum dimmability is around of 60%. One of the prices of this positive characteristics of modern lamps, is the electromagnetic compatibility EMC. It is well known that the modern lamps have a common part, and this is the electronic ballast. And as all electronics circuits, the electronic ballasts are an important source of EMC noise emission. The noise emission of electronic ballast is mainly conducted emission type. Start from construction of electronic ballast which contains an AC/DC converter and a buffer capacitor the emission of half harmonics is presented too. The emission of half harmonics is proportionally with the cost of lamps, because the cost of lamps depends by the methods used for noise emission rejection too. Typically the cheaper lamps have a higher noise emission than the expensive lamps. Known of noise emission lamps separately is not enough for characterization of low noise emission from lighting network. The low frequency noise emission of a lighting network is lower than in case of a single lamp. The variation of temperature determines a variation of low frequency noise emission too.

scholarly journals Vessel noise levels drive behavioural responses of humpback whales with implications for whale-watching

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Kate R Sprogis ◽  
Simone Videsen ◽  
Peter T Madsen
Keyword(s):  
Low Frequency ◽  
Humpback Whales ◽  
Noise Levels ◽  
Whale Watching ◽  
Noise Emission ◽  
Sensory Stimuli ◽  
Fitness Consequences ◽  
Controlled Exposure ◽  
Vessel Noise ◽  
The Impact

Disturbance from whale-watching can cause significant behavioural changes with fitness consequences for targeted whale populations. However, the sensory stimuli triggering these responses are unknown, preventing effective mitigation. Here, we test the hypothesis that vessel noise level is a driver of disturbance, using humpback whales (Megaptera novaeangliae) as a model species. We conducted controlled exposure experiments (n = 42) on resting mother-calf pairs on a resting ground off Australia, by simulating whale-watch scenarios with a research vessel (range 100 m, speed 1.5 knts) playing back vessel noise at control/low (124/148 dB), medium (160 dB) or high (172 dB) low frequency-weighted source levels (re 1 μPa RMS@1 m). Compared to control/low treatments, during high noise playbacks the mother’s proportion of time resting decreased by 30%, respiration rate doubled and swim speed increased by 37%. We therefore conclude that vessel noise is an adequate driver of behavioural disturbance in whales and that regulations to mitigate the impact of whale-watching should include noise emission standards.

scholarly journals VARIATION OF HARMONICS EMISSION FROM MODERN LAMPS IN A POWER SUPPLY NETWORK

2019 ◽  
Vol 25 (4) ◽  
Author(s):  
ROBERT ISTOK
Keyword(s):  
Electromagnetic Compatibility ◽  
Low Frequency ◽  
Low Noise ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Noise Emission ◽  
Electronic Ballast ◽  
Fluorescent Lamps ◽  
The Cost

<p>The objective of this paper is to prove the relationship between the Total <br />Harmonics Disturbance emission of lamps network and the number of lamps. In the lighting <br />field the LED lighting emission diode is the absolutely winner. The low power consumption <br />and the characteristics of LED made it ideally for most of indoor and outdoor applications. <br />The dimmability of the LEDs which is between 0% and 100% made it ideally for intelligent <br />lighting applications. This large dimmability range could be obtained only with <br />incandescent and halogen bulbs, compare to CFL compact fluorescent lamps where the <br />maximum dimmability is around of 60%. One of the prices of this positive characteristics of <br />modern lamps, is the electromagnetic compatibility EMC. It is well known that the modern <br />lamps have a common part, and this is the electronic ballast. And as all electronics circuits, <br />the electronic ballasts are an important source of EMC noise emission. The noise emission <br />of electronic ballast is mainly conducted emission type. Start from construction of <br />electronic ballast which contains an AC/DC converter and a buffer capacitor the emission <br />of half harmonics is presented too. The emission of half harmonics is proportionally with <br />the cost of lamps, because the cost of lamps depends by the methods used for noise <br />emission rejection too. Typically the cheaper lamps have a higher noise emission than the <br />expensive lamps. Known of noise emission lamps separately is not enough for <br />characterization of low noise emission from lighting network. The low frequency noise <br />emission of a lighting network is lower than in case of a single lamp. The variation of <br />temperature determines a variation of low frequency noise emission too.</p>

scholarly journals Water level oscillations in Monterey Bay and Harbor

Ocean Science ◽  
2015 ◽  
Vol 11 (3) ◽  
pp. 439-453 ◽  
Author(s):  
J. Park ◽  
W. V. Sweet ◽  
R. Heitsenrether
Keyword(s):  
Water Level ◽  
Wave Energy ◽  
Normal Modes ◽  
Low Frequency ◽  
Water Levels ◽  
Level Data ◽  
Modal Amplitude ◽  
Primary Driver ◽  
Potential Mode ◽  
Offshore Wave

Abstract. Seiches are normal modes of water bodies responding to geophysical forcings with potential to significantly impact ecology and maritime operations. Analysis of high-frequency (1 Hz) water level data in Monterey, California, identifies harbor modes between 10 and 120 s that are attributed to specific geographic features. It is found that modal amplitude modulation arises from cross-modal interaction and that offshore wave energy is a primary driver of these modes. Synchronous coupling between modes is observed to significantly impact dynamic water levels. At lower frequencies with periods between 15 and 60 min, modes are independent of offshore wave energy, yet are continuously present. This is unexpected since seiches normally dissipate after cessation of the driving force, indicating an unknown forcing. Spectral and kinematic estimates of these low-frequency oscillations support the idea that a persistent anticyclonic mesoscale gyre adjacent to the bay is a potential mode driver, while discounting other sources.

scholarly journals DEUFRABASE: A Simple Tool for the Evaluation of the Noise Impact of Pavements in Typical Road Geometries

Environments ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 27 ◽  
Author(s):  
Michel Bérengier ◽  
Judicaël Picaut ◽  
Bettina Pahl ◽  
Denis Duhamel ◽  
Benoit Gauvreau ◽  
...  
Keyword(s):  
Traffic Noise ◽  
Emission Spectra ◽  
Low Noise ◽  
Noise Emission ◽  
Simple Method ◽  
Acceptable Error ◽  
The Road ◽  
Noise Impact ◽  
On The Road ◽  
The Impact

Traffic noise is considered by people as one of the most important sources of environmental discomfort. A way to limit the traffic noise is to reduce the noise emission, for example, by using specific low noise pavements, particularly in suburban areas. However, in real situations, it can be difficult to evaluate the impact of a given pavement, because it depends, for example, on the road geometry, the meteorological conditions, or the distance of the receiver position. Finally it can be difficult to select the most appropriate pavement for a given noise reduction objective. In this paper, a simple method is proposed to evaluate the noise impact of a pavement, in typical road geometries and environmental conditions. The proposed approach uses two databases, the first one based on measurements of emission spectra of road vehicles on several typical pavements, the second one made of pre-calculations of noise propagation for typical road configurations. Finally, the method is implemented in an interactive web tool, called DEUFRABASE, which allows one to obtain a fast estimation of the L Aeq (1 h or 24 h) and L den noise levels for various pavements and road configurations, as functions of the traffic flow and composition. By comparing the method with measurements, it is showed that the tool, although based on a restricted number of pavements and on several simplifications, can predict the noise impact of typical road configurations, with an acceptable error, most often less than 2 dB.

Expansion joints with low noise emission

2008 ◽  
pp. 51-52
Author(s):  
C O’Suilleabhain ◽  
G Moor ◽  
T Spuler
Keyword(s):  
Low Noise ◽  
Noise Emission ◽  
Expansion Joints

scholarly journals A Low-Power Opamp-Less Second-Order Delta-Sigma Modulator for Bioelectrical Signals in 0.18 µm CMOS

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6456
Author(s):  
Fernando Cardes ◽  
Nikhita Baladari ◽  
Jihyun Lee ◽  
Andreas Hierlemann
Keyword(s):  
Low Power ◽  
Low Frequency ◽  
Cmos Technology ◽  
Low Noise ◽  
Second Order ◽  
Frequency Noise ◽  
Voltage Controlled Oscillator ◽  
Noise Shaping ◽  
Delta Sigma Modulator ◽  
Delta Sigma

This article reports on a compact and low-power CMOS readout circuit for bioelectrical signals based on a second-order delta-sigma modulator. The converter uses a voltage-controlled, oscillator-based quantizer, achieving second-order noise shaping with a single opamp-less integrator and minimal analog circuitry. A prototype has been implemented using 0.18 μm CMOS technology and includes two different variants of the same modulator topology. The main modulator has been optimized for low-noise, neural-action-potential detection in the 300 Hz–6 kHz band, with an input-referred noise of 5.0 μVrms, and occupies an area of 0.0045 mm2. An alternative configuration features a larger input stage to reduce low-frequency noise, achieving 8.7 μVrms in the 1 Hz–10 kHz band, and occupies an area of 0.006 mm2. The modulator is powered at 1.8 V with an estimated power consumption of 3.5 μW.

scholarly journals Low Frequency Noise Emission From a Natural Gas Compressor Station

1987 ◽  
Author(s):  
Manfred Sieminski ◽  
Manfred Schneider
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Low Frequency ◽  
Frequency Noise ◽  
Compressor Station ◽  
Low Frequency Noise ◽  
Noise Emission ◽  
Combustion Chambers ◽  
The Subject ◽  
Remarkable Reduction

Low Frequency Noise at Gas Turbines A natural gas compressor station that was equipped with Hispano Suiza Turbines THM 1202 emitted high intensity noise between 20 Hz and 40 Hz, causing window vibrations and standing waves within the living rooms of a nearby residential area. Since additional sound attenuation by increasing the volume of the exhaust silencers was impossible, further investigations were carried out to explain the mechanism of this low frequency noise emission. By changing the flame pattern inside the combustion chambers of the turbines it was possible to achieve a remarkable reduction at 31.5 Hz amounting to 15 dB. The investigation procedure leading to the final results will be the subject of this presentation.

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