United States Naval Research Laboratory Research Articles

Dynamics of intraseasonal oscillations in the Bay of Bengal during summer monsoons captured by mooring observations

The intraseasonal variabilities of current and temperature in the southern Bay of Bengal (BoB) were examined using in-situ observations collected in the upper 500 m of the water column for a period of 20 months, between December 2013 and August 2015. Data were sampled by six subsurface moorings deployed by the United States Naval Research Laboratory as part of an international effort focused on the dynamics of the northern Indian Ocean. The moored observations captured motions of multiple time-scales, including seasonal circulations, eddies, and planetary waves that underlie intraseasonal variability. This study focuses on 30–60-day intraseasonal oscillations (ISOs). Spectral analysis of currents shows enhanced energy and momentum fluxes for the period 46–52-days. The ISO velocity fluctuations were coherent in the upper 500 m of the water column, strongest near the surface and nearly uniform below 100 m. The ISO kinetic energy appeared at the beginning of the 2014 summer monsoon and lasted throughout the summer, but the associated potential energy dropped rapidly after it peaked at the beginning of the monsoon season.The correlation between the 30–60 day ISOs of local winds and the oceanic variability below 120 m depth was fund to be as small as 25% suggesting thus that the local winds were not the main forcing mechanism for ISOs. The 30–60-day band-passed sea-surface-height anomalies indicate westward propagating anomalies with phase speeds between 0.17 m s−1 at 8°N and 0.43 m s−1 at 4°N, within the phase-speed ranges of mode-1 and mode-2 linear baroclinic Rossby waves, pointing to the role of Rossby waves in 30–60-day ISOs.The background mean flow acceleration resulting from the meridional divergence of wave momentum flux in the thermocline was about 10−8 m s−2. As a result, within a wave period, ISOs can enhance the eastward flow in the thermocline by about 25%. The negative shear production computed for the same period is consistent with this finding, suggesting that the mean flow has gained kinetic energy at the expense of the ISO band at a rate of about 0.5×10−8 m2 s−2. The meridional heat-flux divergence was -10−7 °C s−1, and has a tendency for cooling the thermocline by about 0.5 °C when the ISOs are active. The ISOs appear to play an important role in the ocean dynamics of the southern BoB during the summer monsoon.

The Application of Magnetometers and Electromagnetic Induction Sensors in UXO Detection

This paper introduces the physical model of unexploded ordnance (UXO) in the magnetization process and the formula derivation of the magnetic dipole model. The application of magnetometers and electromagnetic induction sensors in the detection of UXO is introduced. The magnetometers introduce the total field measurements technology of the CS optical-pump marine magnetometer and the MagSTAR (Magnetic Scalar Triangulation and Ranging) gradient detection technology. The electromagnetic induction sensors introduce the working theories and the popular product models of Geophex company and Geonics Ltd. The method of detecting UXO by MTADS of United States Naval Research Laboratory (The multisensor towed array detection system) compares the difference between the United States Naval Research Laboratory for target recognition.

Examination of Metal-Oxidizing Bacteria and Accumulated Corrosion Products on 300 Series Stainless Steels

Event Abstract Back to Event Examination of Metal-Oxidizing Bacteria and Accumulated Corrosion Products on 300 Series Stainless Steels Treva T. T. Brown1, 2 and Jason S. Lee1, 2* 1 United States Naval Research Laboratory, United States 2 United States Naval Research Laboratory, United States The objective of this work is provide fundamental understanding of the relationship between metal-oxidizing bacteria, accumulated corrosion products and pitting in 300 series stainless steels. The 300 series stainless steel (SS) designation contains many different compositions but the common factors among them are: 18 wt% Cr and 8 wt% Ni (18-8). 300 series SS is routinely used in naval systems, e.g., fuel transfer lines. However, localized pitting on 300 series SS, especially at welds, has caused catastrophic failures of these materials. Pitting in these alloys has been investigated extensively and in most cases the failures have been diagnosed as microbiologically influenced corrosion without any demonstration of microorganisms or biomineralogy. Pitting is typically associated with tubercles or mounds of accumulated corrosion products attributed to the activities of metal–oxidizing bacteria (MOB). Tubercles on the surface of these alloys in oxygenated, chloride-containing waters causes under-deposit corrosion that initiates a series of events, leading to aggressive corrosion, i.e., fixation of a small anode surrounded by a large cathode, dissolution of metal at the anode, acidity under the tubercle and ingress of chloride. However, the structure, mineralogy and microbiology for tubercles on 300 series SS have never been examined in detail. Surface analytical techniques will be used to relate the chemical, mineralogical, electrochemical and magnetic properties of accumulated corrosion products on 300 series SS in waters containing MOB and chloride. Keywords: corrosion, Microbiologically Influenced Corossion, metal oxidizing bacteria, Biomineralogy, Stainless steel (3) Conference: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference , Orlando, Florida, United States, 17 Sep - 20 Sep, 2018. Presentation Type: Oral Presentation Topic: Enviornmental and Green Chemistry Citation: Brown TT and Lee JS (2019). Examination of Metal-Oxidizing Bacteria and Accumulated Corrosion Products on 300 Series Stainless Steels. Front. Chem. Conference Abstract: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference . doi: 10.3389/conf.fchem.2018.01.00031 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 15 Oct 2018; Published Online: 17 Jan 2019. * Correspondence: Dr. Jason S Lee, United States Naval Research Laboratory, Washington D.C., United States, jason.lee@nrlssc.navy.mil Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Treva T. T Brown Jason S Lee Google Treva T. T Brown Jason S Lee Google Scholar Treva T. T Brown Jason S Lee PubMed Treva T. T Brown Jason S Lee Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Fabrication of Luminescent Quantum Dot Thiol-yne Nanocomposites via UV Photopolymerization

Event Abstract Back to Event Fabrication of Luminescent Quantum Dot Thiol-yne Nanocomposites via UV Photopolymerization Darryl A. Boyd1*, Michael H. Stewart1, Kimihiro Susumu2, Eunkeu Oh2, Christopher G. Brown1, Collin C. McClain1 and Edward P. Gorzkowski1 1 United States Naval Research Laboratory, United States 2 Sotera Defense Solutions (United States), United States Polymers containing quantum dots are fabricated using thiol-yne chemistry in order to develop strong, flexible and luminescent materials. To accomplish this, novel ligands were synthesized and used to functionalize quantum dots (QDs) of various diameters. These functionalized QDs were then incorporated into thiol-yne prepolymer matrices. These matrices were subsequently polymerized to form QD thiol-yne nanocomposite polymers. The resulting transparent nanocomposites expressed the size-specific color of the QDs within them when exposed to UV irradiation, demonstrating that QDs can be incorporated into thiol-yne polymers without significantly altering QD expression. With the inclusion of QDs, thiol-yne nanocomposite polymers are promising candidates for use in numerous applications including as waveguides, optical lens materials, and sensor applications. Keywords: Thiol Click, quantum dot, nanocomposite, photopolymerization, Additive manufacturing Conference: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference , Orlando, Florida, United States, 17 Sep - 20 Sep, 2018. Presentation Type: Oral Presentation Topic: Nanochemistry Citation: Boyd DA, Stewart MH, Susumu K, Oh E, Brown CG, McClain CC and Gorzkowski EP (2019). Fabrication of Luminescent Quantum Dot Thiol-yne Nanocomposites via UV Photopolymerization. Front. Chem. Conference Abstract: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference . doi: 10.3389/conf.fchem.2018.01.00005 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 04 Oct 2018; Published Online: 17 Jan 2019. * Correspondence: Dr. Darryl A Boyd, United States Naval Research Laboratory, Washington D.C., United States, darryl.anthony@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Darryl A Boyd Michael H Stewart Kimihiro Susumu Eunkeu Oh Christopher G Brown Collin C McClain Edward P Gorzkowski Google Darryl A Boyd Michael H Stewart Kimihiro Susumu Eunkeu Oh Christopher G Brown Collin C McClain Edward P Gorzkowski Google Scholar Darryl A Boyd Michael H Stewart Kimihiro Susumu Eunkeu Oh Christopher G Brown Collin C McClain Edward P Gorzkowski PubMed Darryl A Boyd Michael H Stewart Kimihiro Susumu Eunkeu Oh Christopher G Brown Collin C McClain Edward P Gorzkowski Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Effective NOx remediation from a surrogate flue gas using the US NRL Electra electron beam facility

Nitric oxide (NOx) emission is under restrictive federal regulations because of its negative impact on atmosphere, biosphere, and human health. Therefore, its removal has been a subject of extensive research to develop new efficient and cost effective techniques that can be applied on an industrial scale. In this work, we study both experimentally and theoretically an effective removal of NOx pollutants from a surrogate flue gas (SFG) using high power electron beam (e-beam) pulses. SFG is a simulant for exhaust from coal combustion power plants (82% N2, 6% O2, 12% CO2, and ∼100 ppm of NOx). The pulsed electron beam is generated using the United States Naval Research Laboratory Electra facility, which delivers e-beams with energies of ∼500 keV and a power pulse duration of ∼140 ns. During the e-beam irradiation, the energetic electrons generate a non-equilibrium plasma containing chemically active species, which then react with NOx to form harmless substances. A non-equilibrium time-dependent model is developed to describe NOx remediation from SFG. The model combines e-beam deposition rates obtained by solving the electron Boltzmann equation and extensive plasma chemistry modeling, which follows the species on a time scale from sub-nanoseconds to a few seconds. NOx decomposition as a function of electron beam parameters is studied. It is demonstrated experimentally that short (ns) pulses are the most efficient for NOx removal. A sharp reduction of NOx was measured with e-beam power deposition increasing, following the trend predicted by the model, achieving a 20 fold reduction to ∼5 ppm at energy deposition ∼20 J/l.

US Naval Research Laboratory focus issue: introduction.

Rather than concentrate on a single topic, this feature issue presents the wide variety of research in optics that takes place at a single institution, the United States Naval Research Laboratory (NRL) and is analogous to an NRL feature issue published in Applied Optics in 1967. NRL is the corporate research laboratory for the Navy and Marine Corps. It conducts a broadly based multidisciplinary program of scientific research and advanced technological development in the physical, engineering, space, and environmental sciences related to maritime, atmospheric, and space domains. NRL's research is directed toward new and improved materials, techniques, equipment, and systems in response to identified and anticipated Navy needs. A number of articles in this issue review progress in broader research areas while other articles present the latest results on specific topics.

Krypton Fluoride (KrF) Laser Driver for Inertial Fusion Energy

The United States Naval Research Laboratory (NRL) is developing the krypton fluoride (KrF) laser technology for a direct drive laser inertial fusion energy (IFE) power plant. The overall projected wall plug efficiency for KrF laser system is ~7%, including thermal management and optical losses. There are two KrF lasers at NRL. The first, Nike, provides up to 3 kJ of laser light per shot for experimental research in KrF laser-target interactions. The Electra Laser at NRL is a repetitively pulsed electron beam pumped 700 Joule KrF laser facility. The objective with Electra is to develop technologies to meet the IFE requirements for repetition rate, efficiency, and durability. Electra produces over 750 Joules in oscillator mode. Based on experiments, there is expected to be virtually no degradation in the laser focal profile, even at 5 Hz, high efficiency operation. Progress in durability has lead to achievement of KrF laser runs for 10 continuous hours at 2.5 Hz (90,000 shots) and 100 minutes at 5 Hz (over 30,000 shots). The main impediment to achieving long duration runs is the present pulsed power system that is based on spark gap switches. NRL has developed a new all solid state system that has operated for 11 million pulses continuously at 10 Hz and is based on components attaining 300 million pulses. These studies show an electron beam pumped KrF laser should be a viable approach for a laser fusion energy driver.

KrF Laser Development for Fusion Energy

The United States Naval Research Laboratory is developing an electron beam pumped krypton fluoride laser technology for a direct drive inertial fusion energy power plant. The repetitively pulsed krypton fluoride laser technology being developed meets the fusion energy requirements for laser beam quality, wavelength, and repetition rate. The kryptonfluoride laser technology is projected, based on experiments, to meet the requirements for wall plug efficiency and durability. The projected wall plug efficiency based on experiments is greater than 7 percent. The Electra laser using laser triggered gas switches has conducted continuous operation for 90,000 shots at 2.5 Hertz operation (ten hours). The Electra laser has achieved greater than 700 Joules per pulse at 1 and 2.5 Hertz repetition rate. The comparison of krypton fluoride laser performance with krypton fluoride kinetics code shows good agreement for pulse shape and laser yield. Development and operation of a durable pulse power system with solid state switches has achieved a continuous run of 11 million pulses into a resistive load at 10Hz.

NOx removal with multiple pulsed electron beam free of catalysts or reagents

A catalyst free approach for nitrogen oxides (NOx) removal has been developed at the United States Naval Research Laboratory. Our goals were to assess the ability of pulsed electron beam to enhance NOx removal at potential lower capital cost with greater efficiency than other large scale NOx removal methods. Removal efficiency over 95% has been attained for NOx concentrations of 1000 parts per million (ppm), 500 ppm and 200 ppm in nitrogen atmosphere. The NOx concentration dropped from 204 ppm to below 4.8 ppm after 10 shots supplying a total dose of 65 kGy. The resultant chemicals after catalyst free pulsed electron beam processing of NOx are nitrogen and oxygen, same as components of air. Pulsed electron beams in a catalyst free approach remove a larger percentage of NOx than continuous wave electron beam with a catalyst. Catalyst free approach removes issues of handling, collecting, transporting and efficiently distributing chemical byproducts. Pulsed electron beams are as efficient as continuous wave electron beams for small removal percentages and have a significant advantage at higher fractional removal percentages of NOx. Preferential destruction of NO species relative to the removal of NO2 species is observed in the pulsed electron beam reaction chamber. The energy required to remove a kilogram of NOx is nearly the same at pressures of 1.16 atmospheres and 1.02 atmospheres.

Observed volume fluxes in the Bosphorus Strait

[1] Pairs of moorings containing acoustic Doppler current profilers (ADCPs) were deployed at each end of the Bosphorus Strait as a part of the United States Naval Research Laboratory's “Exchange Processes in Ocean Straits (EPOS)” project. The moorings were deployed in September 2008 and remained in place for about half a year. For the first time, current velocity profiles were collected concurrently at both ends of the strait. They well resolved the two-layer exchange flow and were used to estimate volume flux time series. These estimates clearly indicated that there was a mean net volume flux of over 100 km3/yr directed from the Black Sea to the Sea of Marmara over this period. The upper-layer fluxes showed distinct temporal variability whereas the lower-layer fluxes varied less. Volume fluxes were maximized at over 1500 km3/yr in the upper layer and over 1100 km3/yr in the lower layer, with an upper-layer mean of about 400 km3/yr and a lower-layer mean of about 300 km3/yr. Fluxes in both layers were highly coherent with the bottom pressure difference between the southern and northern ends of Bosphorus Strait, and they can be fairly well predicted from this pressure difference. The fluxes in the upper layer were also influenced by atmospheric forcing, but generally less so than by the bottom pressure difference.

The genesis of Typhoon Nuri as observed during the Tropical Cyclone Structure 2008 (TCS-08) field experiment – Part 1: The role of the easterly wave critical layer

Abstract. An observational and real-time model forecast study of the genesis of Typhoon Nuri during the Tropical Cyclone Structure 2008 (TCS-08) field campaign in the western North Pacific sector is presented. Analysis and observational data show that the surrounding base state is an easterly trade wind flow and the precursor disturbance to Typhoon Nuri is an easterly wave that originates in the ITCZ in the Central Pacific. This disturbance can be tracked more than 10 days prior to tropical storm formation. An overview of the field data is presented here using a newly proposed dynamical framework for tropical cyclone formation within the critical layer of an easterly wave. Despite propagating through a hostile environment ripe with strong vertical wind shear and relatively dry air, the easterly wave critical layer protects the proto-vortex and allows it to gestate until it reaches a more favorable environment. Within this protective "Kelvin cat's eye flow" located within the wave's critical layer existed a sweet spot, defined as the intersection between the wave trough and critical latitude, which is the preferred location for tropical cyclogenesis. Global Forecast System Final Analyses and IR satellite imagery, which shows convective bands wrapping around the sweet spot as genesis nears, confirm that this sweet spot is the location where Typhoon Nuri's dominant low-level circulation emerges. United States Air Force C130 and Naval Research Laboratory P3 research flights on 16 and 17 August collected flight-level, dropwindsonde, and Doppler radar data that allowed an evaluation of the dynamic and thermodynamic processes within the cat's eye circulation. The dropwindsonde analyses identifies the precursor easterly wave disturbance on 16 August and identifies an area of weak low-level cyclonic circulation on 17 August. Real-time forecasts were produced using operational global prediction model data to support scientific missions during TCS-08. These forecasts were found to be useful in flight planning discussions and predicted Typhoon Nuri's eventual genesis latitude within 1.5 degrees 72 h in advance.

Development of a compact cesium-seeded magnetically confined plasma ion source for accelerator mass spectrometry

A gas-fed negative ion source for use in an accelerator mass spectrometry system has been built at the United States Naval Research Laboratory. This ion source is a filament driven plasma ion source using a multicusp magnet arrangement for plasma confinement. Our specific design was assisted by modeling using the SIMION code to optimize beam extraction optics. In addition to the ion source modeling, preliminary characterization of the plasma behavior was performed, which showed the typical and expected order of magnitude increase in collected plasma current when a multicusp magnetic arrangement is employed versus the case with no magnets. Future work will involve implementing a Langmuir probe for more detailed characterization of the plasma, investigation of the effects of using a symmetric rather than a multicusp magnet arrangement, and ultimately the extraction and characterization of ion beams from the source.

Measurement methodology of projectors in confined environment

The intent of this paper is to describe the first stages of potentially ongoing collaborative research between the United States Naval Research Laboratory's Underwater Sound Reference Detachment (USRD) and France's DCN In genierie cenae Sud Departement Lutte Sous-Marine (DCN/SUD/DLSM). The immediate focus of this collaborative work is on high Q electroacoustic transducer calibration in reverberation limited environments. This paper will be divided into three sections: the first one, a description of the motivating problem in reverberation limited measurements, the second one, a description of the two techniques developed by each laboratory, finally, research results and the activities necessary to complete the work in progress

Atmospheric Radon Measurements in the Arctic; Fronts, Seasonal Observations, and Transport of Continental Air to Polar Regions

Abstract Radon was determined in the atmosphere over the Arctic Ocean in flights of a United States Naval Research Laboratory aircraft in April and May 1974. Simultaneously collected air samples were analyzed for carbon monoxide, methane, trichlorofluoromethane, and carbon tetrachloride. Flights at 305 m altitude found significant spatial and temporal variations in Arctic air masses and the formation of succinct fronts during warm air advection. Radon measurements, Defense Meteorological Satellite Project images, and conventional meteorological charts demonstrated the transport of North American air west of Greenland and of marine air and European air east of Greenland to the Arctic Ocean basin. Radon and the other trace gases served to identify stratospheric air masses, and showed that continental southern air did not penetrate over the Arctic Ocean basin at high altitudes (7.6–8.2 km). Trace gas measurements aboard ships and aircraft during different seasons in the Arctic suggest that seasonal variation...

Effect of Prior Heat Treatment on the Strength of Glass Fibers Measured at Room Temperature

Journal of the American Ceramic SocietyVolume 48, Issue 7 p. 385-385 Effect of Prior Heat Treatment on the Strength of Glass Fibers Measured at Room Temperature N. M. CAMERON, N. M. CAMERONSearch for more papers by this author N. M. CAMERON, N. M. CAMERONSearch for more papers by this author First published: July 1965 https://doi.org/10.1111/j.1151-2916.1965.tb14770.xCitations: 5 This research was supported by the United States Naval Research Laboratory under Contract Nonr 2947 (02) (X). The writer is research associatc, Department of Theoretical and Applied Mechanics, University of Illinois, Urbana, Illinois. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume48, Issue7July 1965Pages 385-385 RelatedInformation

The United States Naval Research Laboratory at Belleview, Washington, District of Columbia

The United States Naval Research Laboratory at Belleview, Washington, District of Columbia

Researches related to terrestrial magnetism and electricity of the United States Naval Research Laboratory

The investigation of the possibilities of locating storm‐areas by means of radio static‐direction recorders is being continued with stations several hundred miles apart.An analysis of radio conditions during the past twelve years brought out the fact that, dealing with yearly averages, the radio phenomena fell in more consistently with the relative sunspot‐number than with the solar constant or the terrestrial‐magnetic character.

Researches related to terrestrial magnetism and electricity of the United States Naval Research Laboratory

Equipment is being developed to record automatically and continuously the directions of radio static. It is planned to install the static direction‐recorders at stations several hundred miles apart in order to investigate their possibility in locating storms.Ross Gunn has prepared a quantitative theory of the electricity of rain and thunderstorms (Terr. Mag v. 40, pp. 79–106, 1935) which yields agreement with observation. The theory is based on the hypothesis that each droplet of water and its surrounding ionized vapor constitutes a concentration‐cell of about 60 millivolts difference of potential. He has dealt with (Terr. Mag., v. 39, pp. 265–276, 1934) the origin of the Sun's electric field from the standpoint of the systematic drift of the ions of the solar atmosphere.

Echo‐sounding of the Kennelly‐Heaviside layer

Observations of the Kennelly‐Heaviside layer have been continued at the Department of Terrestrial Magnetism of the Carnegie Institution of Washington by the writer and L. R. Hafstad. The United States Naval Research Laboratory, as before, has kindly transmitted the necessary schedules of signals. Multivibrator‐modulation was used, giving very sharp pulse‐signals on 4,435 and 8,870 kilocycles. A marked diurnal‐variation in the effective height of the layer and in the echo‐pattern received for each transmitted pulse or “peak” was observed in three 24‐hour series of observations taken during the early fall and winter. The echo‐pattern shows multiplicities during the day and evening but becomes very complex at night. A few observations made during the magnetic disturbance of October 17 to 19, 1928, showed an unusually great effective height and a change in the echo‐pattern.