Although four species of odontocete and four species of baleen whale have been recorded in Prydz Bay,their vocalizations have been rarely investigated.Underwater vocalizations were recorded during March 2017 in Prydz ...Although four species of odontocete and four species of baleen whale have been recorded in Prydz Bay,their vocalizations have been rarely investigated.Underwater vocalizations were recorded during March 2017 in Prydz Bay,Antarctica.Bio-duck sounds,downsweeps,inverted“u”shape signals,whistles,pulsed sounds,and broadband clicks were recorded.Bio-duck sounds and downsweeps were associated with Antarctic minke whales(Balaenoptera bonaerensis)based on visual observations.Similarities between inverted“u”shape signals,biphonic calls,and clicks with vocalizations previously described for killer whales(Orcinus orca)lead us believe the presence of Antarctic killer whales.According to sound structures,signal characteristics,and recording location,Antarctic type C killer whales were the most probable candidates to produce these detected calls.These represent the fi rst detection of inverted“u”shape signals in Antarctic waters,and the fi rst report of Antarctic killer whale in Prydz Bay based on passive acoustic monitoring.The co-existence of Antarctic minke and killer whales may imply that minke whales can detect diff erences between the sounds of mammal-eating and fi sh-eating killer whales.Our descriptions of these underwater vocalizations contribute to the limited body of information regarding the distribution and acoustic behavior of cetaceans in Prydz Bay.展开更多
Oxygen ebullition is typically ignored in long-term measurements of net ecosystem productivity(NEP),which reflects whether systems are net heterotrophic or autotrophic based on diel changes in oxygen.The solubility of...Oxygen ebullition is typically ignored in long-term measurements of net ecosystem productivity(NEP),which reflects whether systems are net heterotrophic or autotrophic based on diel changes in oxygen.The solubility of oxygen in seawater is a function of temperature,salinity,and pressure.Warm,high-salinity seawater has low oxygen solubility,and when combined with the photosynthetic productivity of macrophytes in shallow,clear waters,oxygen ebullition frequently occurs.The presence of mixed-phase oxygen in supersaturated seawater creates difficulties for oxygen measurements because sensors cannot measure dissolved and gas phases simultaneously.Therefore,dissolved oxygen measurements must be taken in conjunction with separate ebullition measurements to develop an accurate oxygen budget needed to characterize NEP.Here,we seek to understand the drivers of NEP for a Thalassia testudinum meadow in the Gulf of Mexico and calculate ebullition rates using acoustic sensing.We hypothesize that oxygen ebullition will substantially increase NEP,particularly during the summer months because of photosynthetic dependence on temperature and irradiance.We found that the seagrass meadow is typically oxygen saturated during the hours 0700 to 2200 with maximum saturation occurring at 1400.Acoustic-based methods and general additive modeling both found highest ebullition rates in July/August.High respiration led to an apparent net heterotrophic system(NEP=-2.1 mmol O_(2)m^(-2)d^(-1)),but accounting for air-sea exchange and ebullition causes the system to be autotrophic(NEP=54 mmol O_(2)m^(-2)d^(-1)).This study demonstrates the importance of including ebullition into NEP calculations and the viability of acoustics as a tool for monitoring aquatic productivity.展开更多
A wireless acoustic sensor network was realized using wireless sensor nodes equipped with microphone condensers,in which its sensor nodes were configured to capture poultry sound data and transmit it via the network t...A wireless acoustic sensor network was realized using wireless sensor nodes equipped with microphone condensers,in which its sensor nodes were configured to capture poultry sound data and transmit it via the network to a collection point.A high performance computer can process these large volumes of animal audio signals under different behaviors.By performing data signal processing and analyzing the audio signal,poultry sound can be achieved and then transformed into their corresponding behavioral modes for welfare assessment.In this study,compressive sensing algorithm was developed in consideration of the balance between the power saving from compression ratio and the computational cost,and a low power consumption as well as an inexpensive sensor node was designed as the elementary unit of poultry acoustic data collecting and transmission.Then,a Zigbee-based wireless acoustic sensor network was developed to meet the challenges of short transmission range and limited resources of storage and energy.Experimental results demonstrate that the compressive sensing algorithm can improve the communication performances of the wireless acoustic sensor network with high reliability,low packet loss rate and low energy consumption.展开更多
Accurate estimations of animal population size are pivotal for implementing management strategies properly.Recapture technique based on sounds as a specimen identifcation mark has barely been used for marine mammals.H...Accurate estimations of animal population size are pivotal for implementing management strategies properly.Recapture technique based on sounds as a specimen identifcation mark has barely been used for marine mammals.However,inferring abundance estimates from acoustic methods could enhance the accuracy and precision of population size assessments.Here,we tested the possibility of using signature whistles as individual marks for estimating the size of common bottlenose dolphin(Tursiops truncatus)populations.Data were continuously collected for 326 days in 2015–2016,by using a fxed acoustic device located in the Sicily Strait(Italy).The SIGID method was applied to identify Signature Whistles Types(SWTs)over 7,000 h of recordings.Eighty SWTs were detected as long as their stereotyped fundamental frequency contours were repeated in bouts of at least 6 renditions.The mean SWTs monthly recording rate resulted in 0.19(Standard deviation=0.16),with 20 SWTs recorded over 5 or more different encounters(until a maximum of 30 encounters).The Jolly–Seber model(with POPAN formulation)was run in Mark software to estimate the population size.The estimated population size resulted in 171 bottlenose dolphins(95%confdence interval=137–215).Even if the detection and identifcation of signature whistles required crucial precautions,and animals could be detected differently from visual techniques,the population size estimate obtained was comparable with previous results based on physical marks data.These outcomes demonstrated that signature whistles can be considered a strongly effective tool for integrating traditional mark-recapture techniques with fnely estimated dolphins’population abundances.展开更多
A corrosion resistant CuNi cladding was deposited on SM45C (equivalent to AISI1045) substrate by DC inverse arc welding. During the welding process, a three channel acoustic emission (AE) monitoring system was applied...A corrosion resistant CuNi cladding was deposited on SM45C (equivalent to AISI1045) substrate by DC inverse arc welding. During the welding process, a three channel acoustic emission (AE) monitoring system was applied to detect the crack signals generating from both the cladding process and after cladding. Characteristics of the welding crack signal and noise signal had been analyzed systematically. Based on the record time of the signal, the solidification crack and delayed crack were distinguished. By two-dimensional AE source location, the crack position was located, and then investigated by scanning electron microscopy (SEM). Results showed that the AE system could detect the welding crack with high sensitivity and the two-dimensional source location could accurately determine the crack position. Microstructures of the cladding and heat affected zone (HAZ) were examined. Dendrites in the cladding and coarse grains in the HAZ were found.展开更多
To better understand the mechanical properties of marble at Jinping II hydropower station, this paper examines the changes of brittle rocks in excavation damaged zones(EDZs) before and after excavation of tunnel with ...To better understand the mechanical properties of marble at Jinping II hydropower station, this paper examines the changes of brittle rocks in excavation damaged zones(EDZs) before and after excavation of tunnel with the tunnel boring machine(TBM). The paper attempts to employ the acoustic emission(AE) to study the AE characteristics and distribution of rockburst before and after TBM-excavated tunnel. It is known that the headrace tunnel #2, excavated by the drill-and-blast(D&B) method, is ahead of the headrace tunnel #3 that is excavated by TBM method. The experimental sub-tunnel #2–1, about 2000 m in depth and 13 m in diameter, between the two tunnels is scheduled. In the experimental sub-tunnel #2–1, a large number of experimental boreholes are arranged, and AE sensors are installed within 10 m apart from the wall of the headrace tunnel #3. By tracking the microseismic signals in rocks, the location, frequency, quantity, scope and intensity of the microseismic signals are basically identifed. It is observed that the AE signals mainly occur within 5 m around the rock wall, basically lasting for one day before tunnel excavation and a week after excavation. Monitoring results indicate that the rockburst signals are closely related to rock stress adjustment. The rock structure has a rapid self-adjustment capacity before and after a certain period of time during tunneling. The variations of rock stresses would last for a long time before reaching a fnal steady state. Based on this, the site-specifc support parameters for the deep tunnels can be accordingly optimized.展开更多
Zirconia ceramics have become increasingly widely used in recent years and are favored by relevant enterprises. From the traditional dental field to aerospace, parts manufacturing has been used, but there is limited r...Zirconia ceramics have become increasingly widely used in recent years and are favored by relevant enterprises. From the traditional dental field to aerospace, parts manufacturing has been used, but there is limited research on the deformation and damage process of zirconia ceramics. This article analyzes the acoustic emission characteristics of each stage of ceramic damage from the perspective of acoustic emission, and explores its deformation process characteristics from multiple perspectives such as time domain, frequency, and EWT modal analysis. It is concluded that zirconia ceramics exhibit higher brittleness and acoustic emission strength than alumina ceramics, and when approaching the fracture, it tends to generate lower frequency acoustic emission signals.展开更多
Passive acoustic monitoring(PAM)technology is increasingly becoming one of the mainstream methods for bird monitoring.However,detecting bird audio within complex natural acoustic environments using PAM devices remains...Passive acoustic monitoring(PAM)technology is increasingly becoming one of the mainstream methods for bird monitoring.However,detecting bird audio within complex natural acoustic environments using PAM devices remains a significant challenge.To enhance the accuracy(ACC)of bird audio detection(BAD)and reduce both false negatives and false positives,this study proposes a BAD method based on a Dual-Feature Enhancement Fusion Model(DFEFM).This method incorporates per-channel energy normalization(PCEN)to suppress noise in the input audio and utilizes mel-frequency cepstral coefficients(MFCC)and frequency correlation matrices(FCM)as input features.It achieves deep feature-level fusion of MFCC and FCM on the channel dimension through two independent multi-layer convolutional network branches,and further integrates Spatial and Channel Synergistic Attention(SCSA)and Multi-Head Attention(MHA)modules to enhance the fusion effect of the aforementioned two deep features.Experimental results on the DCASE2018 BAD dataset show that our proposed method achieved an ACC of 91.4%and an AUC value of 0.963,with false negative and false positive rates of 11.36%and 7.40%,respectively,surpassing existing methods.The method also demonstrated detection ACC above 92%and AUC values above 0.987 on datasets from three sites of different natural scenes in Beijing.Testing on the NVIDIA Jetson Nano indicated that the method achieved an ACC of 89.48%when processing an average of 10 s of audio,with a response time of only 0.557 s,showing excellent processing efficiency.This study provides an effective method for filtering non-bird vocalization audio in bird vocalization monitoring devices,which helps to save edge storage and information transmission costs,and has significant application value for wild bird monitoring and ecological research.展开更多
In this context, we applied the radial water jet drilling(RJD) technology to drill five horizontal holes into a quarry wall of the Gildehaus quarry close to Bad Bntheim, Germany. For testing the state-of-the-art jetti...In this context, we applied the radial water jet drilling(RJD) technology to drill five horizontal holes into a quarry wall of the Gildehaus quarry close to Bad Bntheim, Germany. For testing the state-of-the-art jetting technology, a jetting experiment was performed to investigate the influence of geological heterogeneity on the jetting performance and the hole geometry, the influence of nozzle geometry and jetting pressure on the rate of penetration, and the possibility of localising the jetting nozzle utilizing acoustic activity. It is observed that the jetted holes can intersect fractures under varying angles, and the jetted holes do not follow a straight path when jetting at ambient surface condition. Cuttings from the jetting process retrieved from the holes can be used to estimate the reservoir rock permeability. Within the quarry, we did not observe a change in the rate of penetration due to jetting pressure variations.Acoustic monitoring was partially successful in estimating the nozzle location. Although the experiments were performed at ambient surface conditions, the results can give recommendations for a downhole application in deep wells.展开更多
Background:Cities differ from non-urban environments by the intensity,scale,and extent of anthropogenic pres-sures,which can drive the occurrence,physiology,and behavior of the organisms thriving in these settings.Tra...Background:Cities differ from non-urban environments by the intensity,scale,and extent of anthropogenic pres-sures,which can drive the occurrence,physiology,and behavior of the organisms thriving in these settings.Traits as green cover often predict the occurrence patterns of bird species in urban areas.Yet,anthropogenic noise and artificial light at night(ALAN)could also limit the presence and disrupt the behavior of birds.However,there is still a dearth of knowledge about the influence of urbanization through noise and light pollution on nocturnal bird species ecology.In this study,we assessed the role of green cover,noise,and light pollution on the occurrence and vocal activity of the Mottled Owl(Ciccaba virgata)in the city of Xalapa(Mexico).Methods:We obtained soundscape recordings in 61 independent sites scattered across the city of Xalapa using autonomous recording units.We performed a semi-automated acoustic analysis of the recordings,corroborating all Mottled Owl vocalizations.We calculated two measures of anthropogenic noise at each study site:daily noise(during 24 h)and masking noise(mean noise amplitude at night per site that could mask the owl’s vocalizations).We further performed generalized linear models to relate green cover,ALAN,daily noise,and masking noise in relation to the owl’s occurrence(i.e.,detected,undetected).We also ran linear models to assess relationships among the beginning and ending of vocal activity with ALAN,and with the anthropogenic and masking noise levels at the moment of which vocalizations were emitted.Finally,we explored variations of the vocal activity of the Mottled Owl measured as vocalization rate across time.Results:The presence of Mottled Owls increased with the size of green cover and decreased with increases in both artificial light at night and noise levels.At the temporal scale,green cover was positively related with the ending of the owl’s vocal activity,while daily noise and ALAN levels were not related to the timing and vocal output(i.e.,number of vocalizations).Furthermore,the Mottled Owl showed a marked peak of vocal activity before dawn than after dusk.Although anthropogenic noise levels varied significantly across the assessed time,we did not find an association between high vocal output during time periods with lower noise levels.Conclusions:Spatially,green cover area was positively related with the presence of the Mottled Owl in Xalapa,while high noise and light pollution were related to its absence.At a temporal scale,daily noise and ALAN levels were not related with the timing and vocal output.This suggests that instead of environmental factors,behavioral contexts such as territoriality and mate interactions could drive the vocal activity of the Mottled Owl.Further studies need to incorporate a wider seasonal scale in order to explore the variation of different vocalizations of this species in relation to environmental and biological factors.展开更多
Two major human-caused threats to ecosystems are habitat modification and the increasing frequency and intensity of extreme weather events.To study the combined effect of these threats,the authors used acoustic monito...Two major human-caused threats to ecosystems are habitat modification and the increasing frequency and intensity of extreme weather events.To study the combined effect of these threats,the authors used acoustic monitoring of bats along a habitat modification gradient on the island of Okinawa,Japan.During the observation period,the island experienced numerous typhoons and one supertyphoon.Native bat species remained active even at high wind speeds(up to 30 m/s in some cases).Milder typhoons had no observable effect on bat populations,with activity levels fully recovering within a few hours or days.The super typhoon also did not seem to affect bats in fully or partially forested habitats but caused their local disappearance at the urban site,which they have not re-colonized three years after the event.Notably,bats that disappeared at the urban site were species roosting in well-protected places such as caves and concrete structures.In all cases,the biomass of small flying insects and the acoustic activity of insects recovered within days after extreme weather events.Thus,the striking difference between habitats in supertyphoon effects on bats cannot be explained by the super typhoon directly killing bats,destroying their roosting sites,or decreasing the abundance of their prey.The results underscore the importance of preserving natural habitats in areas particularly affected by changing climate and show that the survival of species and ecosystems during the numerous episodes of climate change in the Earth’s history does not necessarily mean their ability to survive the accelerating climate change of our time.展开更多
In order to study acoustic emission （AE） characteristics of pitting corrosion on 304 stainless steel under higher than normal temperature, pitting corrosion process of 304 stainless steel in 6° ferric chloride ...In order to study acoustic emission （AE） characteristics of pitting corrosion on 304 stainless steel under higher than normal temperature, pitting corrosion process of 304 stainless steel in 6° ferric chloride solution at 70° was monitored by AE technology. Conventional parameter-based approach and signal-based analysis were combined to deal with recorded AE signals, and micrographic observation was performed for further verification. The results showed that AE hit and energy increased gradually with time and reached the peak at certain time, and then declined and maintained a stable condition. Signal waveform was mainly composed of low-frequency （〈 100 kHz） flexural wave with larger amplitude and energy and high-frequency （〉 100 kHz） expansion wave with lower amplitude and energy. The research results have some certain significance for AE monitoring of pitting corrosion on 304 stainless steel under higher than normal temperature.展开更多
The redistribution of three-dimensional(3D)geostress during underground tunnel excavation can easily induce to shear failure along rockmass structural plane,potentially resulting in engineering disasters.However,the c...The redistribution of three-dimensional(3D)geostress during underground tunnel excavation can easily induce to shear failure along rockmass structural plane,potentially resulting in engineering disasters.However,the current understanding of rockmass shear behavior is mainly based on shear tests under2D stress without lateral stress,the shear fracture under 3D stress is unclear,and the relevant 3D shear fracture theory research is deficient.Therefore,this study conducted true triaxial cyclic loading and unloading shear tests on intact and bedded limestone under different normal stress σ_(n) and lateral stressσ_(p)to investigate the shear strength,deformation,and failure characteristics.The results indicate that under differentσ_(n)and σ_(p),the stress–strain hysteresis loop area gradually increases from nearly zero in the pre-peak stage,becomes most significant in the post-peak stage,and then becomes very small in the residual stage as the number of shear test cycles increases.The shear peak strength and failure surface roughness almost linearly increase with the increase inσ_(n),while they first increase and then gradually decrease asσ_(p)increases,with the maximum increases of 12.9%for strength and 15.1%for roughness.The shear residual strength almost linearly increases withσ_(n),but shows no significant change withσ_(p).Based on the acoustic emission characteristic parameters during the test process,the shear fracture process and microscopic failure mechanism were analyzed.As the shear stressτincreases,the acoustic emission activity,main frequency,and amplitude gradually increase,showing a significant rise during the cycle near the peak strength,while remaining almost unchanged in the residual stage.The true triaxial shear fracture process presents tensile-shear mixture failure characteristics dominated by microscopic tensile failure.Based on the test results,a 3D shear strength criterion considering the lateral stress effect was proposed,and the determination methods and evolution of the shear modulus G,cohesion c_(jp),friction angleφ_(jp),and dilation angleψjpduring rockmass shear fracture process were studied.Under differentσ_(n)andσ_(p),G first rapidly decreases and then tends to stabilize;cjp,φ_(jp),andψjpfirst increase rapidly to the maximum value,then decrease slowly,and finally remain basically unchanged.A 3D shear mechanics model considering the effects of lateral stress and shear parameter degradation was further established,and a corresponding numerical calculation program was developed based on3D discrete element software.The proposed model effectively simulates the shear failure evolution process of rockmass under true triaxial shear test,and is further applied to successfully reveal the failure characteristics of surrounding rocks with structural planes under different combinations of tunnel axis and geostress direction.展开更多
Passive acoustic monitoring has the potential to be a useful tool for population estimation of sound-producing fish and mammals(mostly whales).Previous work on population estimates of callers employed a simple cross-c...Passive acoustic monitoring has the potential to be a useful tool for population estimation of sound-producing fish and mammals(mostly whales).Previous work on population estimates of callers employed a simple cross-correlation technique with recordings from two acoustic sensors,and the current work extends the technique to two configurations of a 3-acoustic sensors array using two different sounds,i.e.,chirps which is commonly generated by damselfish(Dascyllus aruanus),humpback whales(Megaptera novaeangliae),dugongs(Dugong dugon)etc.,species,and grunts which is commonly generated by Japanese gurnard(Chelidonichthys kumu),Grey gurnard(Eutrigla gurnardus),gulf toadfish(O.beta),etc.,species.We compared simulated results from this technique with values determined by theoretical approach.We have found that an increasing number of cross-correlation function(CCF)provide better results using this technique.However,the technique has some limitations including negligence of multipath interference,assuming the delays to be integer.展开更多
During the Yangtze Freshwater Dolphin Expedition 2012,Yangtze finless porpoises(Neophocaena asiaeorientalis)were acoustically monitored in 9 port areas at night.During 6566 min of nocturnal monitoring,porpoise sonar w...During the Yangtze Freshwater Dolphin Expedition 2012,Yangtze finless porpoises(Neophocaena asiaeorientalis)were acoustically monitored in 9 port areas at night.During 6566 min of nocturnal monitoring,porpoise sonar was detected for 488 min(7.43%of the total time).Of all 81 encounters,the longest echolocation span obtained was 102.9 min,suggesting frequent and prolonged porpoise occupation of the port areas.A combined total of 2091 click trains were recorded,with 129(6.2%)containing minimum inter-click intervals(ICIs)below 10 ms(termed a buzz).Buzzes with a decrease in ICIs and search and approach phases that resembled feeding echolocation signals accounted for 44.2%(N=52)of all buzzes.Buzzes with an increase in ICIs,suggesting a mirrored prey capture phase,accounted for 20.2%(N=26)and could reflect attempts to locate escaped prey because they were followed by approach-phase feeding buzzes.Anecdotal evidence of porpoises fleeing the proximity of vessels was observed.The recordings indicating clusters of porpoises feeding near the port areas suggest a forced choice for feeding due to the relatively higher prey availability in the port areas compared to other areas in the Yangtze River that are probably overfished.展开更多
The associations between feeding activities and environmental variables inform animal feeding tactics that max-imize energetic gains by minimizing energy costs while maximizing feeding success.Relevant studies in aqua...The associations between feeding activities and environmental variables inform animal feeding tactics that max-imize energetic gains by minimizing energy costs while maximizing feeding success.Relevant studies in aquatic animals,particularly marine mammals,are scarce due to difficulties in the observation of feeding behaviors in aquatic environments.This data scarcity concurrently hinders ecosystem-basedfishery management in the context of small toothed-cetacean conservation.In the present study,a passive acoustic monitoring station was deployed in an East Asianfinless porpoise habitat in Laizhou Bay to investigate potential relationships between East Asianfinless porpoises and their prey.The data revealed that porpoises were acoustically present nearly every day during the survey period.Porpoise detection rates differed between spring and autumn in concert with activities offish choruses.During spring,fish choruses were present throughout the afternoon,and this was the time when porpoise vocalizations were the most frequently detected.During autumn,whenfish choruses were absent,porpoise detec-tion rates decreased,and diurnal patterns were not detected.The close association betweenfish choruses andfin-less porpoise activities implies an“eavesdropping”feeding strategy to maximize energetic gains,similar to other toothed cetaceans that are known to engage similar feeding strategies.Underwater noise pollution,particularly those maskingfish choruses,could interruptfinless porpoises’feeding success.Fisheries competing soniferousfishes withfinless porpoise could impactfinless porpoise viability through ecosystem disruption,in addition tofishing gear entanglement.展开更多
The underwater soundscape is an important ecological element affecting numerous aquatic animals,in particular dolphins,which must identify salient cues from ambient ocean noise.In this study,temporal variations in the...The underwater soundscape is an important ecological element affecting numerous aquatic animals,in particular dolphins,which must identify salient cues from ambient ocean noise.In this study,temporal variations in the soundscape of Jiaotou Bay were monitored from February 2016 to January 2017,where a population of Indo-Pacific humpback dolphins(Sousa chinensis)has recently been a regular sighting.An autonomous acoustic recorder was deployed in shallow waters,and 1/3-octave band sound pressure levels(SPLs)were calculated with central frequencies ranging from 25 Hz to 40 kHz,then were grouped into 3 subdivided bands via cluster analysis.SPLs at each major band showed significant differences on a diel,fishing-related period,seasonal,and tidal phase scale.Anthropogenic noise generated by passing ships and underwater explosions were recorded in the study area.The fish and dolphin acoustic activities both exhibited diel and seasonal variations,but no tidal cycle patterns.A negative significant relationship between anthropogenic sound detection rates and dolphin detection rates were observed,and fish detection rates showed no effect on dolphin detection rates,indicating anthropogenic activity avoidance and no forced foraging in dolphins in the study area.The results provide fundamental insight into the acoustic dynamics of an important Indo-Pacific humpback dolphin habitat within a coastal area affected by a rapid increase in human activity,and demonstrate the need to protect animal habitat from anthropogenic noises.展开更多
基金Supported by the National Natural Science Foundation of China(No.41906170)the Indian Ocean Ninety-east Ridge Ecosystem and Marine Environment Monitoring and Protection(No.DY135-E2-4)+1 种基金the Cooperation of Top Predators Observation in the Southern Ocean(No.QT4519003)the China-ASEAN Maritime Cooperation Fund。
文摘Although four species of odontocete and four species of baleen whale have been recorded in Prydz Bay,their vocalizations have been rarely investigated.Underwater vocalizations were recorded during March 2017 in Prydz Bay,Antarctica.Bio-duck sounds,downsweeps,inverted“u”shape signals,whistles,pulsed sounds,and broadband clicks were recorded.Bio-duck sounds and downsweeps were associated with Antarctic minke whales(Balaenoptera bonaerensis)based on visual observations.Similarities between inverted“u”shape signals,biphonic calls,and clicks with vocalizations previously described for killer whales(Orcinus orca)lead us believe the presence of Antarctic killer whales.According to sound structures,signal characteristics,and recording location,Antarctic type C killer whales were the most probable candidates to produce these detected calls.These represent the fi rst detection of inverted“u”shape signals in Antarctic waters,and the fi rst report of Antarctic killer whale in Prydz Bay based on passive acoustic monitoring.The co-existence of Antarctic minke and killer whales may imply that minke whales can detect diff erences between the sounds of mammal-eating and fi sh-eating killer whales.Our descriptions of these underwater vocalizations contribute to the limited body of information regarding the distribution and acoustic behavior of cetaceans in Prydz Bay.
基金funded in part through a grant from the Texas General Land Office(GLO)providing Gulf of Mexico Energy Security Act of 2006 funding made available to the State of Texas and awarded under the Texas Coastal Management Program(22-131-002-D408)Additional funding was provided by the National Science Foundation(2023211).
文摘Oxygen ebullition is typically ignored in long-term measurements of net ecosystem productivity(NEP),which reflects whether systems are net heterotrophic or autotrophic based on diel changes in oxygen.The solubility of oxygen in seawater is a function of temperature,salinity,and pressure.Warm,high-salinity seawater has low oxygen solubility,and when combined with the photosynthetic productivity of macrophytes in shallow,clear waters,oxygen ebullition frequently occurs.The presence of mixed-phase oxygen in supersaturated seawater creates difficulties for oxygen measurements because sensors cannot measure dissolved and gas phases simultaneously.Therefore,dissolved oxygen measurements must be taken in conjunction with separate ebullition measurements to develop an accurate oxygen budget needed to characterize NEP.Here,we seek to understand the drivers of NEP for a Thalassia testudinum meadow in the Gulf of Mexico and calculate ebullition rates using acoustic sensing.We hypothesize that oxygen ebullition will substantially increase NEP,particularly during the summer months because of photosynthetic dependence on temperature and irradiance.We found that the seagrass meadow is typically oxygen saturated during the hours 0700 to 2200 with maximum saturation occurring at 1400.Acoustic-based methods and general additive modeling both found highest ebullition rates in July/August.High respiration led to an apparent net heterotrophic system(NEP=-2.1 mmol O_(2)m^(-2)d^(-1)),but accounting for air-sea exchange and ebullition causes the system to be autotrophic(NEP=54 mmol O_(2)m^(-2)d^(-1)).This study demonstrates the importance of including ebullition into NEP calculations and the viability of acoustics as a tool for monitoring aquatic productivity.
基金the General Program of National Natural Science Foundation of China(No.11364029,No.61461042)Key Projects of National Science and Technology Ministry of China(No.2014BAD08B05)“Prairie talent”Industrial Innovation Team project of Inner Mongolia(No.2014-27).
文摘A wireless acoustic sensor network was realized using wireless sensor nodes equipped with microphone condensers,in which its sensor nodes were configured to capture poultry sound data and transmit it via the network to a collection point.A high performance computer can process these large volumes of animal audio signals under different behaviors.By performing data signal processing and analyzing the audio signal,poultry sound can be achieved and then transformed into their corresponding behavioral modes for welfare assessment.In this study,compressive sensing algorithm was developed in consideration of the balance between the power saving from compression ratio and the computational cost,and a low power consumption as well as an inexpensive sensor node was designed as the elementary unit of poultry acoustic data collecting and transmission.Then,a Zigbee-based wireless acoustic sensor network was developed to meet the challenges of short transmission range and limited resources of storage and energy.Experimental results demonstrate that the compressive sensing algorithm can improve the communication performances of the wireless acoustic sensor network with high reliability,low packet loss rate and low energy consumption.
基金the project“BIOforIU project PONa3_00025-Multidisciplinary Infrastructure for the Study and Development of Marine and Terrestrial Biodiversity in the Perspective of Innovation Union.”Part of the analysis was funded under the National Recovery and Resilience Plan(NRRP),Mission 4 Component 2 Investment 1.4-Call for tender No.3138 of 16 December 2021,rectifed by Decree n.3175 of 18 December 2021 of Italian Ministry of University and Research funded by the European Union-NextGenerationEU,Award Number:Project code CN_00000033,Concession Decree No.1034 of 17 June 2022 adopted by the Italian Ministry of University and Research,Project title"National Biodiversity Future Center-NBFC".
文摘Accurate estimations of animal population size are pivotal for implementing management strategies properly.Recapture technique based on sounds as a specimen identifcation mark has barely been used for marine mammals.However,inferring abundance estimates from acoustic methods could enhance the accuracy and precision of population size assessments.Here,we tested the possibility of using signature whistles as individual marks for estimating the size of common bottlenose dolphin(Tursiops truncatus)populations.Data were continuously collected for 326 days in 2015–2016,by using a fxed acoustic device located in the Sicily Strait(Italy).The SIGID method was applied to identify Signature Whistles Types(SWTs)over 7,000 h of recordings.Eighty SWTs were detected as long as their stereotyped fundamental frequency contours were repeated in bouts of at least 6 renditions.The mean SWTs monthly recording rate resulted in 0.19(Standard deviation=0.16),with 20 SWTs recorded over 5 or more different encounters(until a maximum of 30 encounters).The Jolly–Seber model(with POPAN formulation)was run in Mark software to estimate the population size.The estimated population size resulted in 171 bottlenose dolphins(95%confdence interval=137–215).Even if the detection and identifcation of signature whistles required crucial precautions,and animals could be detected differently from visual techniques,the population size estimate obtained was comparable with previous results based on physical marks data.These outcomes demonstrated that signature whistles can be considered a strongly effective tool for integrating traditional mark-recapture techniques with fnely estimated dolphins’population abundances.
文摘A corrosion resistant CuNi cladding was deposited on SM45C (equivalent to AISI1045) substrate by DC inverse arc welding. During the welding process, a three channel acoustic emission (AE) monitoring system was applied to detect the crack signals generating from both the cladding process and after cladding. Characteristics of the welding crack signal and noise signal had been analyzed systematically. Based on the record time of the signal, the solidification crack and delayed crack were distinguished. By two-dimensional AE source location, the crack position was located, and then investigated by scanning electron microscopy (SEM). Results showed that the AE system could detect the welding crack with high sensitivity and the two-dimensional source location could accurately determine the crack position. Microstructures of the cladding and heat affected zone (HAZ) were examined. Dendrites in the cladding and coarse grains in the HAZ were found.
文摘To better understand the mechanical properties of marble at Jinping II hydropower station, this paper examines the changes of brittle rocks in excavation damaged zones(EDZs) before and after excavation of tunnel with the tunnel boring machine(TBM). The paper attempts to employ the acoustic emission(AE) to study the AE characteristics and distribution of rockburst before and after TBM-excavated tunnel. It is known that the headrace tunnel #2, excavated by the drill-and-blast(D&B) method, is ahead of the headrace tunnel #3 that is excavated by TBM method. The experimental sub-tunnel #2–1, about 2000 m in depth and 13 m in diameter, between the two tunnels is scheduled. In the experimental sub-tunnel #2–1, a large number of experimental boreholes are arranged, and AE sensors are installed within 10 m apart from the wall of the headrace tunnel #3. By tracking the microseismic signals in rocks, the location, frequency, quantity, scope and intensity of the microseismic signals are basically identifed. It is observed that the AE signals mainly occur within 5 m around the rock wall, basically lasting for one day before tunnel excavation and a week after excavation. Monitoring results indicate that the rockburst signals are closely related to rock stress adjustment. The rock structure has a rapid self-adjustment capacity before and after a certain period of time during tunneling. The variations of rock stresses would last for a long time before reaching a fnal steady state. Based on this, the site-specifc support parameters for the deep tunnels can be accordingly optimized.
文摘Zirconia ceramics have become increasingly widely used in recent years and are favored by relevant enterprises. From the traditional dental field to aerospace, parts manufacturing has been used, but there is limited research on the deformation and damage process of zirconia ceramics. This article analyzes the acoustic emission characteristics of each stage of ceramic damage from the perspective of acoustic emission, and explores its deformation process characteristics from multiple perspectives such as time domain, frequency, and EWT modal analysis. It is concluded that zirconia ceramics exhibit higher brittleness and acoustic emission strength than alumina ceramics, and when approaching the fracture, it tends to generate lower frequency acoustic emission signals.
基金supported by the Beijing Natural Science Foundation(5252014)the National Natural Science Foundation of China(62303063)。
文摘Passive acoustic monitoring(PAM)technology is increasingly becoming one of the mainstream methods for bird monitoring.However,detecting bird audio within complex natural acoustic environments using PAM devices remains a significant challenge.To enhance the accuracy(ACC)of bird audio detection(BAD)and reduce both false negatives and false positives,this study proposes a BAD method based on a Dual-Feature Enhancement Fusion Model(DFEFM).This method incorporates per-channel energy normalization(PCEN)to suppress noise in the input audio and utilizes mel-frequency cepstral coefficients(MFCC)and frequency correlation matrices(FCM)as input features.It achieves deep feature-level fusion of MFCC and FCM on the channel dimension through two independent multi-layer convolutional network branches,and further integrates Spatial and Channel Synergistic Attention(SCSA)and Multi-Head Attention(MHA)modules to enhance the fusion effect of the aforementioned two deep features.Experimental results on the DCASE2018 BAD dataset show that our proposed method achieved an ACC of 91.4%and an AUC value of 0.963,with false negative and false positive rates of 11.36%and 7.40%,respectively,surpassing existing methods.The method also demonstrated detection ACC above 92%and AUC values above 0.987 on datasets from three sites of different natural scenes in Beijing.Testing on the NVIDIA Jetson Nano indicated that the method achieved an ACC of 89.48%when processing an average of 10 s of audio,with a response time of only 0.557 s,showing excellent processing efficiency.This study provides an effective method for filtering non-bird vocalization audio in bird vocalization monitoring devices,which helps to save edge storage and information transmission costs,and has significant application value for wild bird monitoring and ecological research.
基金funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No.654662
文摘In this context, we applied the radial water jet drilling(RJD) technology to drill five horizontal holes into a quarry wall of the Gildehaus quarry close to Bad Bntheim, Germany. For testing the state-of-the-art jetting technology, a jetting experiment was performed to investigate the influence of geological heterogeneity on the jetting performance and the hole geometry, the influence of nozzle geometry and jetting pressure on the rate of penetration, and the possibility of localising the jetting nozzle utilizing acoustic activity. It is observed that the jetted holes can intersect fractures under varying angles, and the jetted holes do not follow a straight path when jetting at ambient surface condition. Cuttings from the jetting process retrieved from the holes can be used to estimate the reservoir rock permeability. Within the quarry, we did not observe a change in the rate of penetration due to jetting pressure variations.Acoustic monitoring was partially successful in estimating the nozzle location. Although the experiments were performed at ambient surface conditions, the results can give recommendations for a downhole application in deep wells.
基金supported by the graduate Grant provided by the National Council of Science and Technology(CONACYT 417094 and 416452,respectively)the Doctoral and Master Program of the Instituto de Ecología,A.C.(INECOL,Xalapa)+1 种基金CONACYT(project Grant 251526)a chair fellowship at CIIDIR(researcher number 1640,project number 1781)for financial support。
文摘Background:Cities differ from non-urban environments by the intensity,scale,and extent of anthropogenic pres-sures,which can drive the occurrence,physiology,and behavior of the organisms thriving in these settings.Traits as green cover often predict the occurrence patterns of bird species in urban areas.Yet,anthropogenic noise and artificial light at night(ALAN)could also limit the presence and disrupt the behavior of birds.However,there is still a dearth of knowledge about the influence of urbanization through noise and light pollution on nocturnal bird species ecology.In this study,we assessed the role of green cover,noise,and light pollution on the occurrence and vocal activity of the Mottled Owl(Ciccaba virgata)in the city of Xalapa(Mexico).Methods:We obtained soundscape recordings in 61 independent sites scattered across the city of Xalapa using autonomous recording units.We performed a semi-automated acoustic analysis of the recordings,corroborating all Mottled Owl vocalizations.We calculated two measures of anthropogenic noise at each study site:daily noise(during 24 h)and masking noise(mean noise amplitude at night per site that could mask the owl’s vocalizations).We further performed generalized linear models to relate green cover,ALAN,daily noise,and masking noise in relation to the owl’s occurrence(i.e.,detected,undetected).We also ran linear models to assess relationships among the beginning and ending of vocal activity with ALAN,and with the anthropogenic and masking noise levels at the moment of which vocalizations were emitted.Finally,we explored variations of the vocal activity of the Mottled Owl measured as vocalization rate across time.Results:The presence of Mottled Owls increased with the size of green cover and decreased with increases in both artificial light at night and noise levels.At the temporal scale,green cover was positively related with the ending of the owl’s vocal activity,while daily noise and ALAN levels were not related to the timing and vocal output(i.e.,number of vocalizations).Furthermore,the Mottled Owl showed a marked peak of vocal activity before dawn than after dusk.Although anthropogenic noise levels varied significantly across the assessed time,we did not find an association between high vocal output during time periods with lower noise levels.Conclusions:Spatially,green cover area was positively related with the presence of the Mottled Owl in Xalapa,while high noise and light pollution were related to its absence.At a temporal scale,daily noise and ALAN levels were not related with the timing and vocal output.This suggests that instead of environmental factors,behavioral contexts such as territoriality and mate interactions could drive the vocal activity of the Mottled Owl.Further studies need to incorporate a wider seasonal scale in order to explore the variation of different vocalizations of this species in relation to environmental and biological factors.
文摘Two major human-caused threats to ecosystems are habitat modification and the increasing frequency and intensity of extreme weather events.To study the combined effect of these threats,the authors used acoustic monitoring of bats along a habitat modification gradient on the island of Okinawa,Japan.During the observation period,the island experienced numerous typhoons and one supertyphoon.Native bat species remained active even at high wind speeds(up to 30 m/s in some cases).Milder typhoons had no observable effect on bat populations,with activity levels fully recovering within a few hours or days.The super typhoon also did not seem to affect bats in fully or partially forested habitats but caused their local disappearance at the urban site,which they have not re-colonized three years after the event.Notably,bats that disappeared at the urban site were species roosting in well-protected places such as caves and concrete structures.In all cases,the biomass of small flying insects and the acoustic activity of insects recovered within days after extreme weather events.Thus,the striking difference between habitats in supertyphoon effects on bats cannot be explained by the super typhoon directly killing bats,destroying their roosting sites,or decreasing the abundance of their prey.The results underscore the importance of preserving natural habitats in areas particularly affected by changing climate and show that the survival of species and ecosystems during the numerous episodes of climate change in the Earth’s history does not necessarily mean their ability to survive the accelerating climate change of our time.
文摘In order to study acoustic emission （AE） characteristics of pitting corrosion on 304 stainless steel under higher than normal temperature, pitting corrosion process of 304 stainless steel in 6° ferric chloride solution at 70° was monitored by AE technology. Conventional parameter-based approach and signal-based analysis were combined to deal with recorded AE signals, and micrographic observation was performed for further verification. The results showed that AE hit and energy increased gradually with time and reached the peak at certain time, and then declined and maintained a stable condition. Signal waveform was mainly composed of low-frequency （〈 100 kHz） flexural wave with larger amplitude and energy and high-frequency （〉 100 kHz） expansion wave with lower amplitude and energy. The research results have some certain significance for AE monitoring of pitting corrosion on 304 stainless steel under higher than normal temperature.
基金the National Natural Science Foundation of China(Nos.52469019,52109119,and 52274145)the Chinese Postdoctoral Science Fund Project(No.2022M723408)+1 种基金the Major Project of Guangxi Science and Technology(No.AA23023016)the Technology Project of China Power Engineering Consulting Group Co.,Ltd.(No.DG2-T01-2023)。
文摘The redistribution of three-dimensional(3D)geostress during underground tunnel excavation can easily induce to shear failure along rockmass structural plane,potentially resulting in engineering disasters.However,the current understanding of rockmass shear behavior is mainly based on shear tests under2D stress without lateral stress,the shear fracture under 3D stress is unclear,and the relevant 3D shear fracture theory research is deficient.Therefore,this study conducted true triaxial cyclic loading and unloading shear tests on intact and bedded limestone under different normal stress σ_(n) and lateral stressσ_(p)to investigate the shear strength,deformation,and failure characteristics.The results indicate that under differentσ_(n)and σ_(p),the stress–strain hysteresis loop area gradually increases from nearly zero in the pre-peak stage,becomes most significant in the post-peak stage,and then becomes very small in the residual stage as the number of shear test cycles increases.The shear peak strength and failure surface roughness almost linearly increase with the increase inσ_(n),while they first increase and then gradually decrease asσ_(p)increases,with the maximum increases of 12.9%for strength and 15.1%for roughness.The shear residual strength almost linearly increases withσ_(n),but shows no significant change withσ_(p).Based on the acoustic emission characteristic parameters during the test process,the shear fracture process and microscopic failure mechanism were analyzed.As the shear stressτincreases,the acoustic emission activity,main frequency,and amplitude gradually increase,showing a significant rise during the cycle near the peak strength,while remaining almost unchanged in the residual stage.The true triaxial shear fracture process presents tensile-shear mixture failure characteristics dominated by microscopic tensile failure.Based on the test results,a 3D shear strength criterion considering the lateral stress effect was proposed,and the determination methods and evolution of the shear modulus G,cohesion c_(jp),friction angleφ_(jp),and dilation angleψjpduring rockmass shear fracture process were studied.Under differentσ_(n)andσ_(p),G first rapidly decreases and then tends to stabilize;cjp,φ_(jp),andψjpfirst increase rapidly to the maximum value,then decrease slowly,and finally remain basically unchanged.A 3D shear mechanics model considering the effects of lateral stress and shear parameter degradation was further established,and a corresponding numerical calculation program was developed based on3D discrete element software.The proposed model effectively simulates the shear failure evolution process of rockmass under true triaxial shear test,and is further applied to successfully reveal the failure characteristics of surrounding rocks with structural planes under different combinations of tunnel axis and geostress direction.
文摘Passive acoustic monitoring has the potential to be a useful tool for population estimation of sound-producing fish and mammals(mostly whales).Previous work on population estimates of callers employed a simple cross-correlation technique with recordings from two acoustic sensors,and the current work extends the technique to two configurations of a 3-acoustic sensors array using two different sounds,i.e.,chirps which is commonly generated by damselfish(Dascyllus aruanus),humpback whales(Megaptera novaeangliae),dugongs(Dugong dugon)etc.,species,and grunts which is commonly generated by Japanese gurnard(Chelidonichthys kumu),Grey gurnard(Eutrigla gurnardus),gulf toadfish(O.beta),etc.,species.We compared simulated results from this technique with values determined by theoretical approach.We have found that an increasing number of cross-correlation function(CCF)provide better results using this technique.However,the technique has some limitations including negligence of multipath interference,assuming the delays to be integer.
基金suported by grants from the Knowledge Innovation Program of Chinese Academy of Sciences(No.KSCX2-EW-Z-4)the National Natural Science Foundation of China(No.31170501 and 31070347)+1 种基金the Special Fund for Agro-scientific Research in the Public Interest of the Ministry of Agriculture of China(No.201203086)the Ocean Park Conservation Foundation,Hong Kong.Some logistic support was provided by Wuhan Baiji Conservation Foundation and Societe Generale de Surveillance S.A.Special thanks are also extended to the academic editor and anonymous reviewers for their helpful critique of an earlier version of this manuscript.
文摘During the Yangtze Freshwater Dolphin Expedition 2012,Yangtze finless porpoises(Neophocaena asiaeorientalis)were acoustically monitored in 9 port areas at night.During 6566 min of nocturnal monitoring,porpoise sonar was detected for 488 min(7.43%of the total time).Of all 81 encounters,the longest echolocation span obtained was 102.9 min,suggesting frequent and prolonged porpoise occupation of the port areas.A combined total of 2091 click trains were recorded,with 129(6.2%)containing minimum inter-click intervals(ICIs)below 10 ms(termed a buzz).Buzzes with a decrease in ICIs and search and approach phases that resembled feeding echolocation signals accounted for 44.2%(N=52)of all buzzes.Buzzes with an increase in ICIs,suggesting a mirrored prey capture phase,accounted for 20.2%(N=26)and could reflect attempts to locate escaped prey because they were followed by approach-phase feeding buzzes.Anecdotal evidence of porpoises fleeing the proximity of vessels was observed.The recordings indicating clusters of porpoises feeding near the port areas suggest a forced choice for feeding due to the relatively higher prey availability in the port areas compared to other areas in the Yangtze River that are probably overfished.
基金supported by grants from the China National Offshore Oil Corporation foundation(grant number CF-MEEC/TR/2021-12)the Central Public-interest Scientific Institution Basal Research Fund,CAFS(grant number 2019ZD0201)the Bureau of Fisheries,the Ministry of Agriculture and Rural Affairs of the People’s Republic of China(grant number 125C0505),The research project was permitted by the Ministry of Agriculture and Rural Affairs of the People’s Republic of China.All procedures strictly adhered to Chinese law and ethical guidelines.
文摘The associations between feeding activities and environmental variables inform animal feeding tactics that max-imize energetic gains by minimizing energy costs while maximizing feeding success.Relevant studies in aquatic animals,particularly marine mammals,are scarce due to difficulties in the observation of feeding behaviors in aquatic environments.This data scarcity concurrently hinders ecosystem-basedfishery management in the context of small toothed-cetacean conservation.In the present study,a passive acoustic monitoring station was deployed in an East Asianfinless porpoise habitat in Laizhou Bay to investigate potential relationships between East Asianfinless porpoises and their prey.The data revealed that porpoises were acoustically present nearly every day during the survey period.Porpoise detection rates differed between spring and autumn in concert with activities offish choruses.During spring,fish choruses were present throughout the afternoon,and this was the time when porpoise vocalizations were the most frequently detected.During autumn,whenfish choruses were absent,porpoise detec-tion rates decreased,and diurnal patterns were not detected.The close association betweenfish choruses andfin-less porpoise activities implies an“eavesdropping”feeding strategy to maximize energetic gains,similar to other toothed cetaceans that are known to engage similar feeding strategies.Underwater noise pollution,particularly those maskingfish choruses,could interruptfinless porpoises’feeding success.Fisheries competing soniferousfishes withfinless porpoise could impactfinless porpoise viability through ecosystem disruption,in addition tofishing gear entanglement.
基金supported by the National Key Research and Development Program of China(Grant Nos.2016YFC0300803 and 2018YFC0308602)National Natural Science Foundation of China(Nos.41422604 and 41306169)+1 种基金supported by the China Ocean Mineral Resources R&D Association(No.DY135-E2-4)the Ocean Park Conservation Foundation of Hong Kong(MM02-1516).
文摘The underwater soundscape is an important ecological element affecting numerous aquatic animals,in particular dolphins,which must identify salient cues from ambient ocean noise.In this study,temporal variations in the soundscape of Jiaotou Bay were monitored from February 2016 to January 2017,where a population of Indo-Pacific humpback dolphins(Sousa chinensis)has recently been a regular sighting.An autonomous acoustic recorder was deployed in shallow waters,and 1/3-octave band sound pressure levels(SPLs)were calculated with central frequencies ranging from 25 Hz to 40 kHz,then were grouped into 3 subdivided bands via cluster analysis.SPLs at each major band showed significant differences on a diel,fishing-related period,seasonal,and tidal phase scale.Anthropogenic noise generated by passing ships and underwater explosions were recorded in the study area.The fish and dolphin acoustic activities both exhibited diel and seasonal variations,but no tidal cycle patterns.A negative significant relationship between anthropogenic sound detection rates and dolphin detection rates were observed,and fish detection rates showed no effect on dolphin detection rates,indicating anthropogenic activity avoidance and no forced foraging in dolphins in the study area.The results provide fundamental insight into the acoustic dynamics of an important Indo-Pacific humpback dolphin habitat within a coastal area affected by a rapid increase in human activity,and demonstrate the need to protect animal habitat from anthropogenic noises.
