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.

Sol-Gel synthesis of microcrystalline rare earth orthophosphates

Abstract: Studies of the reactions between rare earth salts and phosphoric acid in aqueous or ethanolic media have shown that in both cases stable gels can be formed. Upon drying, gels prepared in aqueous environments yield macrocrystalline REPO4 products similar to those produced by conventional precipitation and drying. Gels prepared in ethanol, on the other hand, undergo dehydration to form dense microcrystalline products. This observation is based on optical and scanning electron microscopy, as well as on x-ray diffraction studies and infrared spectroscopy. These techniques, as well as differential thermal analysis, indicate that crystal growth of these products takes place around 600−700 °C. The composition of the dehydrated gels produced in both the aqueous and ethanolic systems corresponds to an orthophosphate structure. Other characteristics of the microcrystalline REPO4 products include high resistance to attack by water, absence of coloration upon exposure to gamma rays, and a high index of refraction.

Solute–solvent interactions in chemistry and biology. Part 7. An analysis of mobile phase effects on high pressure liquid chromatography capacity factors and relationships of the latter with octanol–water partition coefficients

Abstract: log k′ values on a C18 stationary phase with 90/10, 75/25, 60/40, 45/55 and 30/70 methanol–water mobile phases are correlated in terms of the generalized linear solvation energy relationship, log k′= XYZo+mVI/100 +sπ*+bβm+aαm where VI is the intrinsic (van der Waals) molar volume, and π*, βm, and αm are the solvatochromic parameters that measure solute dipolarity–polarizability, hydrogen-bond acceptor basicity, and hydrogen-bond donor acidity. The correlation equations are combined with the corresponding equation for octanol–water partition coefficients to generate new equations that demonstrate the exact relationships between the various log k's and log Kow.

Variation among families for characteristics of the adhesive plaque in the barnacle Balanus amphitrite.

Abstract: A quantitative genetics approach was used to examine variation in the characteristics of the adhesive plaque of the barnacle Balanus amphitrite Darwin attached to two silicone substrata. Barnacles settled on silicone polymer films occasionally form thick, soft adhesive plaques, in contrast to the thin, hard plaques characteristic of attachment to other surfaces. The proportion of barnacles producing a thick adhesive plaque was 0.31 for Veridian, a commercially available silicone fouling-release coating, and 0.18 for Silastic T-2, a silicone rubber used for mold-making. For both materials, significant variation among maternal families in the proportion of barnacles producing a thick adhesive plaque was observed, which suggests the presence of genetic variation, or maternal environmental effects, for this plaque characteristic. For the Veridian coating, barnacles expressing the thick adhesive plaque also exhibited significantly reduced tenacity. This represents the first reported case for potential genetic control of intraspecific phenotypic variation in the physical characteristics and tenacity of the adhesive of a fouling invertebrate.

Biofouling and barnacle adhesion data for fouling‐release coatings subjected to static immersion at seven marine sites

Abstract: Little is known about the performance of fouling‐release coatings at different geographical locations. An investigation was designed to measure the differences in biofouling and biofouling adhesion strength on three known silicone formulations and an epoxy control at seven static immersion sites located in California, Florida, Hawaii, Hong Kong, India, Italy and Singapore. The study found that whilst the relative performance of the coatings was similar at each site, there were statistically significant differences in the type and intensity of fouling that developed on the coatings and in barnacle adhesion strength among sites. The results emphasize the importance of evaluating potential coatings at more than one static immersion site.