Naval Surface Warfare Center

About: Naval Surface Warfare Center is a facility organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Radar & Sonar. The organization has 2855 authors who have published 3697 publications receiving 83518 citations. The organization is also known as: NSWC.

In Situ Characterization of Oil-in-Water Emulsions Stabilized by Surfactant and Salt Using Microsensors.

Abstract: Chemically stabilized emulsions are difficult to break because of micelle stability. Many physical and chemical processes have been used for emulsion breaking/separation; however, most operational parameters are based on empirical data and bulk analysis. A multiscale understanding of emulsions is required before these processes can advance further. This study utilized needle-type microsensors and confocal laser scanning microscopy (CLSM) for characterizing simulated bilge water emulsions with different types of surfactants (Triton X-100 and sodium dodecyl sulfate [SDS]) under various NaCl concentrations at microscale. Using microsensors, a diffusion process was clearly visualized across the oil/water interface which appears to be related to emulsion formation kinetics and mass transfer. While emulsion stability decreased with NaCl concentrations, SDS (anionic surfactant) is more likely to form emulsion as salinity increases, requiring more salinity to coalesce SDS emulsions than Triton X-100 (nonionic sur...

Wavelet analysis of a bathymetric profile reveals anomalous crust

Abstract: A 200 km anomalous topographic zone was discovered using wavelet scale analysis in a 1600 km linear bathymetric profile taken northeast of Hawaii. A spectral analysis of the zone shows that the power in wavelengths shorter than 25 km averages 5–10 times lower than the surrounding topography. Conversely, wavelengths longer than 25 km have 2–3 times greater power than nearby topography. Further research reveals that this low-frequency zone correlates with the eastern flank of a regional bathymetric high which has been described by J. Mammerickx [1981]. Details of the features suggest that this zone is a small, abandoned, slow-spreading rift overprinted by a regional thermal swell. The magnitude of the feature is smaller than other, known, abandoned spreading centers, making it easy to overlook without the application of the wavelet transform.

Acoustic response of unexploded ordnance (UXO) and cylindrical targets

Abstract: A series of monostatic and bistatic acoustic scattering measurements were conducted to investigate discrimination and classification capabilities based on the acoustic response of targets for underwater unexploded ordnance (UXO) applications. The measurements were performed during March 2010 and are referred to as the Pond Experiment 2010 (PondEx10), where the fresh water pond contained a sand sediment. The measurements utilized a rail system with a mobile tower and a stationary sonar tower. Each tower is instrumented with receivers while the sources are located on the mobile tower. For PondEx10, eleven targets were deployed at two distinct ground ranges from the mobile tower system. Acoustic data were initially processed using synthetic aperture sonar (SAS) techniques, and the data were further processed to generate acoustic templates for the target strength as a function of frequency and aspect angle. Preliminary results of the processing of data collected from proud targets are presented. Also presented are the results associated with a processing technique that permits isolation of the response of an individual target, which is in close proximity to other targets.

Guidance Algorithm for Range Maximization and Time-of-Flight Control of a Guided Projectile

Abstract: The availability of gun-hardened guidance and control systems has made highly accurate gun-launched rocket-assisted guided projectiles feasible. A composite guidance algorithm is presented for such vehicles. The algorithm is capable of extending range and cross-range capability of the projectile, and allows it to be retargeted after launch. The algorithm also employs model predictive control to control time of flight to allow a salvo of projectiles to arrive simultaneously. The time-of-flight control achieves its objective by trajectory shaping and corrects for winds, off-nominal launch conditions, and rocket motor variations.