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.

Use of curvilinear SAR for three-dimensional target feature extraction

Abstract: The use of curvilinear synthetic aperture radar (CLSAR) is considered for three-dimensional feature extraction of small targets consisting of a small number of distinct point scatterers. CLSAR does not suffer from the ambiguities suffered by interferometric SAR. As CLSAR is a relatively new technology, a self-contained detailed derivation of the data model is presented. The Cramer-Rao bounds of the parameter estimates are also derived. Use of the RELAX algorithm for 3-D target feature extraction with CLSAR for different curvilinear apertures is also described.

Hybrid wireless hull monitoring system for naval combat vessels

Abstract: There is increasing interest by the naval engineering community in permanent monitoring systems that can monitor the structural behaviour of ships during their operation at sea. This study seeks to reduce the cost and installation complexity of hull monitoring systems by introducing wireless sensors into their architectural designs. Wireless sensor networks also provide other advantages over their cable-based counterparts such as adaptability, redundancy, and weight savings. While wireless sensors can enhance functionality and reduce cost, the compartmentalised layout of most ships requires some wired networking to communicate data globally throughout the ship. In this study, 20 wireless sensing nodes are connected to a ship-wide fibre-optic data network to serve as a hybrid wireless hull monitoring system on a high-speed littoral combat vessel (FSF-1 Sea Fighter). The wireless hull monitoring system is used to collect acceleration and strain data during unattended operation during a one-month period at s...

Flywheel energy storage system for electric start and an all-electric ship

Abstract: This paper reports on the investigation and development of flywheel technology as energy storage for shipboard zonal power systems. The goal was to determine where energy storage devices could improve operation and/or reduce life-cycle maintenance costs. Applications where energy storage can provide benefits include uninterruptible power to essential loads, "dark" start capability, load leveling, system stability and pulse weapons. A flywheel energy storage system (FESS), with 25 kWh of available energy, is presented as an alternative to the current shipboard electrochemical battery system, highlighting the advantages for and challenges presented by shipboard applications. Flywheel technology overcomes some of the shortcomings of today's energy storage systems by having an extremely high cyclic-life, limited temperature sensitivity, no chemical hazards, charge rate equal to discharge, and reduced weight and space. As gas turbine electric starter development enters into fleet evaluation, FESS may provide dark ship start capability more so than any other systems being investigated. This paper discusses the critical technical challenges of the FESS for shipboard systems, and the steps for future development.

Analysis of broth‐cultured Bacillus atrophaeus and Bacillus cereus spores

Abstract: Aims: To compare physical properties of spores that were produced in broth sporulation media at greater than 108 spores ml−1. Methods and Results: Bacillus atrophaeus reproducibly sporulated in nutrient broth (NB) and sporulation salts. Microscopy measurements showed that the spores were 0·68 ± 0·11 μm wide and 1·21 ± 0·18 μm long. Coulter Multisizer (CM3) measurements revealed the spore volumes and volume-equivalent spherical diameters, which were 0·48 ± 0·38 μm3 and 0·97 ± 0·07 μm, respectively. Bacillus cereus reproducibly sporulated in NB, sporulation salts, 200 mmol l−1 glutamate and antifoam. Spores were 0·95 ± 0·11 μm wide and 1·31 ± 0·17 μm long. Spore volumes were 0·78 ± 0·61 μm3 and volume-equivalent spherical diameters were 1·14 ± 0·11 μm. Bacillus atrophaeus spores were hydrophilic and B. cereus spores were hydrophobic. However, spore hydrophobicity was significantly altered after treatment with pH-adjusted bleach. Conclusions: The utility of a CM3 for both quantifying Bacillus spores and measuring spore sizes was demonstrated, although the volume between spore exosporium and spore coat was not measured. This study showed fundamental differences between spores from a Bacillus subtilis- and B. cereus-group species. Significance and Impact of the Study: This is useful for developing standard methods for broth spore production and physical characterization of both living and decontaminated spores.