scholarly journals Continental Shelf-Scale Passive Acoustic Detection and Characterization of Diesel-Electric Ships Using a Coherent Hydrophone Array

2017 ◽  
Vol 9 (8) ◽  
pp. 772 ◽  
Author(s):  
Wei Huang ◽  
Delin Wang ◽  
Heriberto Garcia ◽  
Olav Godø ◽  
Purnima Ratilal
Keyword(s):  
Continental Shelf ◽  
Acoustic Detection ◽  
Passive Acoustic ◽  
Hydrophone Array

Assessing Bypassed Hydrocarbons

2021 ◽  
Author(s):  
Stanley Oifoghe ◽  
Nora Alarcon ◽  
Lucrecia Grigoletto
Keyword(s):  
Continental Shelf ◽  
Reservoir Characterization ◽  
Gamma Ray ◽  
West African ◽  
The Novel ◽  
The West ◽  
Present Case Study ◽  
Novel Model

Abstract Hydrocarbons are bypassed in known fields. This is due to reservoir heterogeneities, complex lithology, and limitations of existing technology. This paper seeks to identify the scenarios of bypassed hydrocarbons, and to highlight how advances in reservoir characterization techniques have improved assessment of bypassed hydrocarbons. The present case study is an evaluation well drilled on the continental shelf, off the West African Coastline. The targeted thin-bedded reservoir sands are of Cenomanian age. Some technologies for assessing bypassed hydrocarbon include Gamma Ray Spectralog and Thin Bed Analysis. NMR is important for accurate reservoir characterization of thinly bedded reservoirs. The measured NMR porosity was 15pu, which is 42% of the actual porosity. Using the measured values gave a permeability of 5.3mD as against the actual permeability of 234mD. The novel model presented in this paper increased the porosity by 58% and the permeability by 4315%.

Fish Bioacoustics and Behavior: Passive Acoustic Detection and the Application of a Closed-Circuit Rebreather for Field Study

2001 ◽  
Vol 35 (2) ◽  
pp. 19-28 ◽  
Author(s):  
Phillip S. Lobel
Keyword(s):  
Behavioral Ecology ◽  
Daily Basis ◽  
Open Circuit ◽  
Acoustic Detection ◽  
Ecological Processes ◽  
Detection Technology ◽  
Scientific Goal ◽  
Species Specific ◽  
Passive Acoustic ◽  
And Behavior

The simple thesis of this paper is that using rebreathers to study fish behavioral ecology, especially bioacoustics, is well worth the expense and additional training required. The scientific goal of my bioacoustic research is to determine which fishes produce species-specific sound patterns exclusively with explicit acts of courtship and mating. This provides scientific insight into evolutionary and ecological processes and also provides data necessary to develop the passive acoustic detection technology for monitoring fish reproduction. When used on a daily basis, rebreathers, in my experience, are economical and as practical as open circuit scuba. This is based both on the costs of diving as well as the efficiency of gathering useful data. The use of open circuit SCUBA while conducting acoustic recordings results in a loss of at least 40% of the data due to the bubble noise from a divers breathing. Rebreathers also provide extended bottom time, especially in shallow water, which enhances a diver's ability to observe fish and gather acoustic-behavioral data.

scholarly journals Bioacoustic characterization of mating calls of a freshwater fish (Prochilodus magdalenae) for passive acoustic monitoring

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Sebastián Muñoz-Duque ◽  
Silvia López-Casas ◽  
Héctor Rivera-Gutiérrez ◽  
Luz Jiménez-Segura
Keyword(s):  
Pulse Rate ◽  
Peak Frequency ◽  
Acoustic Monitoring ◽  
Passive Acoustic Monitoring ◽  
Natural Habitats ◽  
Train Duration ◽  
Acoustic Characterization ◽  
Species Specific ◽  
Passive Acoustic

Fish produce sounds that are usually species-specific and associated with particular behaviors and contexts. Acoustic characterization enables the use of sounds as natural acoustic labels for species identification. Males of Prochilodus magdalenae produce mating sounds. We characterized  these sounds and tested their use in natural habitats, to use passive acoustic monitoring for spawning ground identification. We identified two types of acoustic signals: simple pulses and pulse trains. Simple pulses were 13.7 ms long, with peak frequency of 365 Hz, whereas pulse train were 2.3 s long, had peak frequency of 399 Hz, 48.6 pulses and its pulses lasted 12.2 ms, with interpulse interval of 49.0 ms long and 22.3 Hz pulse rate. We did not detect spawning in  absence of male calls nor differences in male sounds at different female densities. We found differences in train duration, pulse rate, and pulse duration in trains, according to the fish's source sites, but these sites were not well discriminated based on bioacoustical variables. In rivers, we located two P. magdalenae spawning grounds and recognized calls from another fish species (Megaleporinus muyscorum). We did not find a significant relationship between fish size and call peak frequency for P. magdalenae.

scholarly journals Acoustic characterization of seafloor habitats on the western continental shelf of India

2007 ◽  
Vol 64 (3) ◽  
pp. 551-558 ◽  
Author(s):  
Bishwajit Chakraborty ◽  
Vasudev Mahale ◽  
Gajanan Navelkar ◽  
B. Ramalingeswara Rao ◽  
R. G. Prabhudesai ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Dual Frequency ◽  
Scattering Process ◽  
Backscatter Signal ◽  
Sediment Volume ◽  
Interface Scattering ◽  
Acoustic Characterization ◽  
Power Law Exponent ◽  
Different Grain Size

Abstract Chakraborty, B., Mahale, V., Navelkar, G., Rao, B. R., Prabhudesai, R. G., Ingole, B., and Janakirinam, G. 2007. Acoustic characterization of seafloor habitats on the western continental shelf of India. – ICES Journal of Marine Science, 64: 551–558. This is a study of the interaction effects of the dual-frequency (210 and 33 kHz) backscatter signal with seafloor sediment and benthic biota along a transect in water 27–83 m deep offshore of the Goa region of India's central west coast. Estimation of the power-law exponent using seafloor topographic data provided equivalent values even when using dual high-frequency systems for different grain-size sediments. Backscatter signals corrected from system-related gain, etc., reveal better correlations with sedimentary and benthic parameters than the estimated coherence parameters (using echo peaks). Statistically, correlations are significant for the 210 kHz backscatter signal with sand and calcium carbonate (CaCO3) sediment content. Also, correlations are higher for macrobenthic biomass (wet weight) and population density with a 210 kHz backscatter strength, emphasizing the dominant seawater–seafloor interface scattering process. For 33 kHz backscatter strength, the absence of such correlations indicates a different scattering process, i.e. dominant sediment volume scattering attributable to the comparatively lower signal attenuation. Additionally, to validate the results, the backscatter signals from other locations in the vicinity of this transect were considered.

Passive Acoustic Detection and Monitoring of Schools of Herring

2008 ◽  
Vol 123 (5) ◽  
pp. 3621-3621
Author(s):  
Thomas R. Hahn ◽  
Gary L. Thomas
Keyword(s):  
Acoustic Detection ◽  
Passive Acoustic
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