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.

DBX-1 – A Lead Free Replacement for Lead Azide

Abstract: Efforts directed towards creating new environmentally friendly replacements for existing primary explosives have resulted in development of copper(I) 5-nitrotetrazolate (DBX-1). The chemical and physical properties of this material have been extensively investigated and it appears that DBX-1 is a suitable drop-in replacement for lead azide in a variety of ordnance applications. DBX-1 is easily prepared, has excellent thermal stability and has safety and performance properties which are equivalent to or exceed those for lead azide. A program to qualify DBX-1 for military use per NAVSEAINST 8020.5C has recently been completed and data has been forwarded to NSWC-IH for submission to Naval Sea Systems Command.

Spectroscopic Determination of Impact Sensitivities of Explosives.

Abstract: A simple theory is developed which predicts impact sensitivities in crystalline explosives from vibrational spectra measured at room temperature. The theory uses Raman spectra of energetic materials to construct vibrational energy level diagrams, which are then used as input for a model designed to calculate the rate of energy transfer from phonon and near-phonon vibrational energy levels to higher energy vibrational levels. Energy transfer rates are determined using Fermi's Golden Rule and results from simple theories of near-resonant energy transfer. The application of the theory and model, using Raman spectra of seven different neat explosive samples, gives results in good agreement with results of drop weight impact tests.

Linear solvation energy relationships. 44. Parameter estimation rules that allow accurate prediction of octanol/water partition coefficients and other solubility and toxicity properties of polychlorinated biphenyls and polycyclic aromatic hydrocarbons.

Abstract: Methods are presented for estimation of V{sub I} (intrinsic molar volume), {pi}*, and {beta} of polychlorinated biphenyls and polycyclic aromatic hydrocarbons. Taken with the equation log K{sub OW} = 0.45 + 5.15V{sub I}/100-1.29 ({pi}* - 0.40{delta}) - 3.60{beta} reported recently by Leahy, these parameter estimation rules allow prediction of log K{sub OW} with a precision that is better than the usual reproducibility of the measurements between laboratories.

Dislocation mechanics-based constitutive equations

Abstract: A review of constitutive models based on the mechanics of dislocation motion is presented, with focus on the models of Zerilli and Armstrong and the critical influence of Armstrong on their development. The models were intended to be as simple as possible while still reproducing the behavior of real metals. The key feature of these models is their basis in the thermal activation theory propounded by Eyring in the 1930’s. The motion of dislocations is governed by thermal activation over potential barriers produced by obstacles, which may be the crystal lattice itself or other dislocations or defects. Typically, in bcc metals, the dislocation-lattice interaction is predominant, while in fcc metals, the dislocation-dislocation interaction is the most significant. When the dislocation-lattice interaction is predominant, the yield stress is temperature and strain rate sensitive, with essentially athermal strain hardening. When the dislocation-dislocation interaction is predominant, the yield stress is athermal, with a large temperature and rate sensitive strain hardening. In both cases, a significant part of the athermal stress is accounted for by grain size effects, and, in some materials, by the effects of deformation twinning. In addition, some simple strain hardening models are described, starting from a differential equation describing creation and annihilation of mobile dislocations. Finally, an application of thermal activation theory to polymeric materials is described.