Heading-control Tests of an Underwater Glider for Virtual Mooring

An underwater glider we are developing for virtual mooring will be able to remain in a designated area for several years, moving between the sea surface and the seafloor up to 2,100 m deep, monitoring the sea environment. It will be able to sleep on the seafloor or while drifting in water to extend the monitoring duration. As described herein, we present results of heading-control tests conducted using a long tank. We also present results of sea tests conducted in Suruga Bay.Date of Conference: 18-21 May 201

Results of the first sea-test of Tsukuyomi: A prototype of underwater gliders for virtual mooring

This paper presents the results of the first sea-test of Tsukuyomi - a prototype of underwater gliders for virtual mooring. Its will be able to stay in a designated water for more than one year, reciprocating between the sea-surface and the seafloor up to 3,000 meters in depth. It will sleep on the seafloor to elongate the operation time. We have successfully conducted tank-test in December 2011 and the first sea-test in March 2012. Although for the sake of safety, a thin string was connected to Tsukuyomi in the first sea-test, the dynamic stability, the maneuverability and the basic function of Tsukuyomi were confirmed.Date of Conference: 14-19 October 2012http://www.godac.jamstec.go.jp/darwin/cruise/kaiyo/ky12-04/

Investigating shellfish deposition and landscape history at the Natia Beach site, Fiji

The relationship between environmental variation and subsistence practices is a central point of discussion in much Oceanic archaeology. While human predation can significantly reduce prey populations, environmental variation also contributes to reductions in prey abundance, possibly leading to increased human competition and resource scarcity. At the Natia Beach site, Nacula Island, Fiji, geoarchaeological evidence suggests that coastal progradation began soon after initial occupation of the coastal plain. Additionally, at approximately 650 BP a marked increase in clay and silt deposition occurred. Changes in coastal geomorphology may be explained by landscape response to regional Mid-Holocene sea level fall combined with human induced soil erosion due to upland settlement. Smaller scale environmental changes associated with climate variability may have also played a role. Additionally, landscape change appears to have had a measurable impact on local nearshore mollusks that are sensitive to high levels of water turbidity. Minor evidence of human exploitation is observable in this shellfish assemblage, although changes in predation pressure may have allowed shellfish populations to recover. Increased ceramic diversity and fortified settlements also appear at approximately 650 BP on Nacula and other parts of Fiji. The suite of changes at Natia may be explained by processes of regional and local environmental changes, and human adaptation in terms of subsistence, spatial organization, and competition

Challenges associated with modeling low-oxygen waters in Chesapeake Bay: a multiple model comparison

As ecosystem and water quality models are becoming more frequently used for operational forecasts and scenario-based management decisions, it is important to understand the relative strengths and limitations of existing models of varying complexity. To this end, simulations of the Chesapeake Bay from eight threedimensional coupled hydrodynamic-oxygen models have been statistically compared to each other and to two years of historical monitoring data. Results show that although models have difficulty resolving the variables typically thought to be the main drivers of dissolved oxygen variability (stratification, nutrients, and chlorophyll), all eight models have significant skill in reproducing the mean and seasonal variability of surface and bottom dissolved oxygen. In addition, models with constant net respiration rates independent of nutrient supply and temperature reproduced observed dissolved oxygen levels about as well as much more complex, nutrient-dependent biogeochemical models. This finding has significant ramifications for short-term hypoxia forecasts, which may be possible with very simple oxygen parameterizations. Chesapeake Bay observations indicate a stronger correlation between the depths of the top of the halocline and the oxycline than between their magnitudes, highlighting that the depth of stratification compresses livable habitat when low-oxygen conditions are present. Furthermore, this implies that improvement in hypoxia simulations will depend more on the ability of models to reproduce the correct mean and variability of the depth of stratification than the precise magnitude of stratification. This study also provides an example of how multiple community models can be used together to improve management decisions based on regulatory model results

Circulation, Volume 27, No. 2

Spring 2022 issue of CCPO Circulation featuring the article Looking Back While Moving Forward, by Sönke Dangendorf.https://digitalcommons.odu.edu/ccpo_circulation/1067/thumbnail.jp

Collection and analysis of data for ship condition monitoring aiming at enhanced reliability and safety

This paper presents the onboard measurement campaign for the case study of a container ship and provides a customary methodology for monitoring important machinery systems. The main principle aim of this paper is to collect important machinery data and parameters from critical systems, located in the engine room of the ship, by determining systems to be monitored, scenarios for monitoring, sensors and suitable portable equipment and physical parameters to be inspected

Wright State University College of Engineering and Computer Science Bits and PCs newsletter, Volume 13, Number 9, November 1997

A twelve page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.https://corescholar.libraries.wright.edu/bits_pcs/1079/thumbnail.jp

Wright State University College of Engineering and Computer Science Bits and PCs newsletter, Volume 13, Number 9, November 1997

A twelve page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.https://corescholar.libraries.wright.edu/bits_pcs/1079/thumbnail.jp