Current research on USS Arizona is focused on a minimum-impact technique for calculating corrosion rate of the battleship's steel hull by analysing physical and chemical properties of marine encrustation covering the exposed hull. An equation is derived that allows concretion thickness, density, and total iron content to be used to calculate corrosion rate of steel hull plate. © 2006 The AuthorsKey words: USS Arizona , steel corrosion, battleship, concretion, marine encrustation. The National Park Service's (NPS) Submerged Resources Center (SRC) and USS Arizona Memorial (USAR) are collaborating with the University of NebraskaLincoln (UNL) on research directed at understanding the nature and rate of natural processes affecting the deterioration of USS Arizona in Pearl Harbour, Hawaii (Fig. 1). The Pennsylvaniaclass battleship USS Arizona , completed in 1916, was sunk in Pearl Harbour on 7 December 1941 during the Japanese attack on the US Navy's Pacific Fleet. In the first 15 minutes of the attack, Arizona endured hits from several bombs, was strafed, and then at about 08.10 the battleship suffered a mortal blow. A Japanese Nakajima B5N2 'Kate' horizontal bomber dropped a single 1760-pound projectile that struck near Turret No. 2, penetrating deep into the battleship's interior before exploding and sympathetically detonating the forward magazine. When the forward magazine exploded most of the battleship's forward half was destroyed below the upper deck, including the forward oil bunkers. The ship sank in minutes, but the explosion ignited fires that raged for 2 1 / 2 days. A total of 1177 sailors and marines aboard Arizona were killed, and nearly 1000 men are still entombed within the ship. USS Arizona 's loss remains the largest single-ship loss of life in US naval history. The USS Arizona Preservation Project is multiyear, interdisciplinary and cumulative, with each element contributing to provide the basic research required to make informed management decisions for the battleship's long-term preservation. This project builds upon prior documentation and research conducted by SRC during the 1980s (Lenihan, 1989) and follows the minimumimpact approach advocated by the NPS (Murphy and Russell, 1997). The primary project focus is acquiring requisite data to understand the complex corrosion and deterioration processes affecting Arizona 's hull, both internally and externally, and modelling and predicting the nature and rate of structural changes ).An important aspect of this project is accurately to determine remaining hull thickness for inclusion in a Finite Element Analysis (FEA) being conducted by the National Institute of Standards and Technology (NIST) in Gaithersburg, MD. The FEA is designed to model Arizona 's structural deterioration and eventual collapseinformation critical for developing a sound, scientifically-based management plan and for determining when, or if, intervening in the vessel's natural deterioration should be considered. A key first-step in this process is determining the remaining thicknes...

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Over the last 40 years, there has been a discernible increase in the number of scholars who have focused their research on early industrial organizations, a field of study that has come to be known as Archaeotechnology. Archaeologists have conducted fieldwork geared to the study of ancient technologies in a cultural context and have drawn on the laboratory analyses developed by materials scientists as one portion of their interpretive program. Papers for this department are solicited and/or reviewed by Michael Notis, a professor and director of the Archaeometallurgy Laboratory (www.Lehigh.edu/~inarcmet) at Lehigh University. The assessment of corrosion on the USS Arizona included the pioneering development of a minimum-impact costeffective technique to determine the corrosion rate of steel-hulled shipwrecks in seawater. The technique, with potential application worldwide, is illustrated in this paper with the application to a World War II Japanese midget submarine submerged in deep waters off the Oahu, Hawaii, coast.

Soundscapes are promising indicators of marine habitat condition, yet this approach remains untested in many ecosystems, and soundscape-ecological relationships remain unclear. In this study, we analyzed soundscapes in kelp forest habitats off the coast of California, USA, in Channel Islands National Park. We investigated if (1) soundscape features correlated with ecological variables and (2) these features differed inside and outside of marine protected areas (MPAs). We recorded 1 min every 15 min at 5 sites from 12 May to 23 June 2018. Three sites were in MPAs with high kelp cover and low urchin density, while 2 were in adjacent, unprotected habitats with low kelp cover and high urchin density. To analyze the data, we calculated soundscape features using detection algorithms and acoustic indices, which we then correlated with annual ecological data from 2016 to 2018. We found that drivers of regime shifts in kelp forests, i.e. sea urchin density, kelp cover, and fish diversity, were significantly related to soundscape features. Sea urchin density was positively correlated and kelp cover negatively correlated with the rate of shrimp snaps. Fish species richness and abundance were positively correlated with the intensity and diel dynamics in the low-frequency bands that contained most fish vocalizations. This study demonstrates that marine soundscapes indicate the condition of kelp forests, which are vulnerable to destruction from urchin overgrazing. If marine soundscapes can reliably indicate the status of ecological drivers, then this approach could be a valuable complement to diver surveys in fully assessing marine ecosystem health.

The American Civil War shipwrecks H. L. Hunley and USS Housatonic have been the focus of intensive archaeological investigations since the discovery of Hunley in 1995. H. L. Hunley, the world's first successful combat submarine, sank the Union blockader USS Housatonic in 1864, but sank immediately afterwards. In work done prior to the recovery of Hunley in 2000, site‐formation processes for both vessels were a primary research focus—a necessary precursor to identifying battlefield behaviour. This paper presents research on the Hunley/Housatonic Naval Engagement Site, where both wrecks are treated as complementary components of a single battlefield site. © 2006 The Authors