A5090388069- Underwater Acoustics Research
- Oceanographic and Atmospheric Processes
- Underwater Vehicles and Communication Systems
- Seismic Waves and Analysis
- Arctic and Antarctic ice dynamics
- Marine animal studies overview
- Methane Hydrates and Related Phenomena
- Seismic Imaging and Inversion Techniques
- Marine and fisheries research
- Ocean Waves and Remote Sensing
- Speech and Audio Processing
- Geophysical Methods and Applications
- Climate change and permafrost
- Maritime Navigation and Safety
- Target Tracking and Data Fusion in Sensor Networks
- Cryospheric studies and observations
- Scientific Research and Discoveries
- Acoustic Wave Phenomena Research
- Geological Studies and Exploration
- Advancements in Battery Materials
- Radar Systems and Signal Processing
- Electrochemical Analysis and Applications
- Blind Source Separation Techniques
- earthquake and tectonic studies
- Electric and Hybrid Vehicle Technologies
University of California, San Diego
2015-2024
Scripps Institution of Oceanography
2015-2024
University of California, Santa Cruz
2021
Naval Postgraduate School
2019-2021
Woods Hole Oceanographic Institution
2001-2021
Leidos (United States)
2020-2021
University of San Diego
2016-2020
Indian Institute of Technology Madras
2019
Nansen Environmental and Remote Sensing Center
2017
Instytut Oceanologii Polskiej Akademii Nauk
2017
Ocean ambient sound data from 1994 to 2001 have been collected using a receiver on the continental slope off Point Sur, California. A temporary, nearby receiving array was used for calibration purposes. The resulting set is compared with long-term averages of earlier measurements made identical over period 1963 1965. This comparison shows that levels exceed 1965 by about 10 dB between 20 and 80 Hz 200 300 Hz, 3 at 100 Hz. Increases in (distant) shipping may account this.
Broadband acoustic signals were transmitted during November 1994 from a 75-Hz source suspended near the depth of sound-channel axis to 700-m long vertical receiving array approximately 3250 km distant in eastern North Pacific Ocean. The early part arrival pattern consists raylike wave fronts that are resolvable, identifiable, and stable. later does not contain identifiable arrivals, due scattering internal-wave-induced sound-speed fluctuations. observed ray travel times differ predictions...
The kinetics of electrochemical decarboxylation formate ions has been studied in detail for the first time as a model reaction examination and radical coupling that occurs with higher aliphatic acids. Current–potential curves have obtained which show sharp transition region, not diffusion controlled, is characteristic passivation phenomena. behavior observed gold, palladium, platinum, gold–palladium alloys. Tafel slopes exchange currents evaluated possible mechanisms are examined relation to...
A series of experiments conducted in the Philippine Sea during 2009-2011 investigated deep-water acoustic propagation and ambient noise this oceanographically geologically complex region: (i) 2009 North Pacific Acoustic Laboratory (NPAL) Pilot Study/Engineering Test, (ii) 2010-2011 NPAL Experiment, (iii) Ocean Bottom Seismometer Augmentation Experiment. The experimental goals included (a) understanding impacts fronts, eddies, internal tides on propagation, (b) determining whether methods,...
Electrochemical kinetic studies on the Kolbe reaction have been carried out in trifluoroacetate–100% trifluoroacetic acid system, where can be examined from an electrochemical viewpoint with minimum complication by oxidative side reactions. High yields of products C 2 F 6 and CO are obtained current–potential curves exhibiting transition behavior linear Tafel regions found. slopes deduced for "Langmuir" "Temkin" conditions surface coverage intermediates compared experimental observations....
The recent invention of rechargeable "modified" manganese oxide materials paves the way to development secondary batteries suitable for numerous applications. This includes alternatives primary dry cells, and lead/ acid nickel‐cadmium batteries. Present results describe performance cells in which modified are coupled with zinc iron. As opposed iron does not affect longevity capacity retention electrodes, has a pejorative effect on materials, owing formation hetaerolite at positive electrode....
The heats of wetting by water cotton cellulose containing various amounts adsorbed and desorbed were measured. These measurements together with those the vapor sorption isotherm used to calculate integral differential enthalpies, free energies, entropies adsorption. Irreversible effects avoided vacuum-drying all samples at room temperature. enthalpy values suggest hydrogen bonding. are explained in terms changes both adsorbate adsorbent.The surface area is calculated applying...
During the Acoustic Engineering Test (AET) of Thermometry Ocean Climate (ATOC) program, acoustic signals were transmitted from a broadband source with 75-Hz center frequency to 700-m-long vertical array 20 hydrophones at distance 3252 km; receptions occurred over period six days. Each received pulse showed early identifiable timefronts, followed by about 2 s highly variable energy. For observations travel-time variance, average shape, and probability density function (PDF) intensity are...
Ocean acoustic tomography (OAT) was proposed in 1979 by Walter Munk and Carl Wunsch as an analogue to x-ray computed axial for the oceans. The oceans are opaque most electromagnetic radiation, but there is a strong waveguide, sound can propagate 10 Mm more with distinct multiply-refracted ray paths. Transmitting broadband pulses ocean leads set of impulsive arrivals at receiver which characterize impulse response channel. peaks observed assumed represent arrival energy traveling along...
Over the decade 1996–2006, acoustic sources located off central California (1996–1999) and north of Kauai (1997–1999, 2002–2006) transmitted to receivers distributed throughout northeast Pacific. The travel times are inherently spatially integrating, which suppresses mesoscale variability provides a precise measure ray‐averaged temperature. Daily average at 4‐day intervals provide excellent temporal resolution large‐scale thermal field. interannual, seasonal, shorter‐period is large, with...
Galvanostatic cathodic discharge and open-circuit decay transients have been obtained for the decarboxylation of formate in formic acid interpreted quantitatively terms adsorption intermediates reaction. These are identified with HCOO • radicals. Extended anodic polarization at platinum particularly palladium leads to formation films an product which considerably thicker than a monolayer. After relatively long times (> 100 seconds) polarization, film growth obeys inverse logarithmic rate...
Acoustic signals transmitted from the ATOC source on Pioneer Seamount off coast of California have been received at various sites around Pacific Basin since January 1996. We describe data obtained using bottom-mounted receivers, including US Navy Sound Surveillance System arrays, ranges up to 5 Mm source. Stable identifiable ray arrivals are observed in several cases, but some receiving arrays not well suited detecting direct arrivals. At 5-Mm range, travel-time variations tidal frequencies...
Orbital forcing has long been the subject of two quite separate communities: tide community is concerned with relatively rapid gravitational forces (periods up to 18.6 yr) and climate long-period Milankovitch insolation terms (exceeding 20 000 yr). The wide gap notwithstanding, subjects have much in common. Keeling Whorf proposed that millennial variability associated high-frequency tidal extending into 10-octave by some nonlinear process. Here, authors distinguish between distinct processes...
This paper provides an overview of the experimental goals and methods Long-range Ocean Acoustic Propagation EXperiment (LOAPEX), which took place in northeast Pacific between September 10, 2004 October 2004. experiment was designed to address a number unresolved issues long-range, deep-water acoustic propagation including effect ocean fluctuations such as internal waves on signal coherence, scattering low-frequency sound, particular, into deep shadow zone. Broadband transmissions centered...
Multimegameter-range acoustic data obtained by bottom-mounted receivers show significant energy penetrating several hundred meters into geometric shadow zones below cusps (caustics) of timefronts computed using climatological databases [B. D. Dushaw et al., IEEE J. Ocean. Eng. 24, 202–214 (1999)]. This penetration is much larger than predicted diffraction theory. Because these are horizontal arrays, they do not provide information on the vertical structure shadow-zone arrivals. Acoustic from...
The Pacific Arctic Region has experienced decadal changes in atmospheric conditions, seasonal sea-ice coverage, and thermohaline structure that have consequences for underwater sound propagation. To better understand acoustics, a set of experiments known as the deep-water Canada Basin acoustic propagation experiment shallow-water was conducted on Chukchi Shelf from summer 2016 to 2017. During experiments, low-frequency signals five tomographic sources located deep basin were recorded by an...
In many interferometers, two fringe signals can be generated in quadrature. The relative phase of the depends on whether optical path length is increasing or decreasing. A system developed which quadrature are digitized and analyzed real time with a digital signal processor to yield linear, high-resolution, wide-dynamic-range displacement transducer. resolution simple Michelson interferometer inexpensive components 5 x 10(-13) m Hz(-1/2) at 2 Hz.
Four acoustic Seagliders were deployed in the Philippine Sea November 2010 to April 2011 vicinity of an tomography array. The gliders recorded over 2000 broadband transmissions at ranges up 700 km from moored sources as they transited between mooring sites. precision glider positioning time reception is important resolve fundamental ambiguity position and sound speed. utilized GPS surface a kinematic model below for positioning. typically underwater about 6.4 h, diving depths 1000 m...
Rapid Arctic warming drives profound change in the marine environment that have significant socio-economic impacts within and beyond, including climate weather hazards, food security, transportation, infrastructure planning resource extraction. These concerns drive efforts to understand predict environmental motivate development of an Region Component Global Ocean Observing System (ARCGOOS) capable collecting broad, sustained observations needed support these endeavors. This paper provides a...
The Arctic Ocean is undergoing dramatic changes in response to increasing atmospheric concentrations of greenhouse gases. 2016-2017 Canada Basin Acoustic Propagation Experiment was conducted assess the effects sea ice and ocean structure Beaufort Gyre on low-frequency underwater acoustic propagation ambient sound. An tomography array with a radius 150 km that consisted six transceivers long vertical receiving measured impulse responses at variety ranges every four hours using broadband...
As an aid to understanding long-range acoustic propagation in the Philippine Sea, statistical and phenomenological descriptions of sound-speed variations were developed. Two moorings oceanographic sensors located western Sea spring 2009 used track constant potential-density surfaces (isopycnals) potential-temperature (isotherms) depth range 120–2000 m. The vertical displacements these are estimate fluctuations from internal waves, while temperature/salinity variability along isopycnals...
Shipping noise and wind are the dominant sources of ocean in frequency band between 20 500 Hz. This paper analyzes that using data from SPICEX experiment, which took place North Pacific 2004–2005, compares results with other experiments. included vertical arrays sensors above below surface conjugate depth, facilitating an analysis depth dependence ambient noise. The includes several key results. First, 2004–05 levels at 50 Hz measured had not increased relative to by Morris [(1978). J....