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: Sonar & Radar. The organization has 2855 authors who have published 3697 publications receiving 83518 citations. The organization is also known as: NSWC.

Synthetic Crystals of Silver with Carbon: 3D Epitaxy of Carbon Nanostructures in the Silver Lattice

Abstract: Noble metals, such as silver, gold, platinum, and palladium, are widely used in many applications due to their high electrical conductivities, high resistance to oxidation and their high malleability. Silver, for example, has the highest ambient electrical (6.3 × 10 7 S m −1 ) and thermal (420 W m −1 K −1 ) conductivities of all metals. Copper is more abundant than noble metals and more economical. It also has high electrical and thermal conductivities. Silver and copper are commonly used in components from consumer electronics to jewelry. However, their practical use and lifetime are limited, or governed by costly maintenance steps, because of their propensity to oxidize or corrode under atmospheric conditions. This is a critical downside in existing applications, as well as a limitation for advanced new applications that require these materials in nanoscale where limited instances of corrosion and/or migration can severely diminish device performance. Cu forms non conducting CuO or Cu 2 O when exposed to the environment. Ag tarnishes by reacting with sulfur [ 1 ] and creating a nonconducting layer of Ag 2 S on the surface of the material, particularly detrimental in nanoscale structures of Ag. [ 2,3 ]

Round-robin measurements of two candidate materials for a Seebeck coefficient Standard Reference Material ™

Abstract: A Standard Reference Material (SRM™) for the Seebeck coefficient is critical for inter-laboratory data comparison and for instrument calibration. To develop this SRM™, we have conducted an international round-robin measurement survey of two candidate materials—undoped Bi2Te3 and constantan (55% Cu and 45% Ni alloy). Measurements were performed in two rounds by twelve laboratories involved in active thermoelectric research using a number of commercial and custom-built measurement systems and techniques. We report the results of these measurements and the statistical analysis performed. Based on this extensive study, we have selected Bi2Te3 as the prototype standard material.

Level Set Hyperspectral Image Classification Using Best Band Analysis

Abstract: We present a supervised hyperspectral classification procedure consisting of an initial distance-based segmentation method that uses best band analysis (BBA), followed by a level set enhancement that forces localized region homogeneity. The proposed method is tested on two hyperspectral images of an urban and rural nature. The proposed method is compared to the maximum likelihood (ML) method using BBA. Quantitative results are compared using segmentation and classification accuracies. Results show that both the initial classification using BBA features and the level set enhancement produced high-quality ground cover maps and outperformed the ML method, as well as previous studies by the authors. For example, with the compact airborne spectrographic imager image, the ML method resulted in accuracies les95.5%, whereas the level set segmentation approach resulted in accuracies as high as 99.7%.

IMMPDA solution to benchmark for radar resource allocation and tracking in the presence of ECM

Abstract: In this paper we present a framework for controlling a phased array radar for tracking highly maneuvering targets in the presence of false alarms and electronic countermeasures (ECM). Algorithms are presented for track formation and maintenance; adaptive selection of target revisit interval, waveform, and detection threshold; and neutralizing techniques for ECM, namely, against a standoff jammer and range gate pull off. This tracker/radar-resource-allocator provides a complete solution to the benchmark problem for target tracking and radar control, which considers six trajectories of highly maneuvering targets, with lateral accelerations up to 7g and longitudinal accelerations up to 2g. Simulation results show an average sampling interval of about 2s while maintaining a track loss less than the maximum allowed 4%.

High strain-rate response of spiropyran mechanophores in PMMA

Abstract: This work was funded by the Defense Threat Reduction Agency Basic Sciences program under grant number HDTRA139181 and managed by Su Peiris.