994 research outputs found

    Directional wave observations, Thimble Shoal light, October 19, 1993 to April 14, 1994

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    The Virginia Institute of Marine Science, in cooperation with the Virginia Department of Conservation and Recreation, Division of Soil and Water conservation, has identified as one of its major goals the systematic study of hydrodynamic processes that affect recreational, shoreline and benthic resources in the coastal zone of the Commonwealth. As one component of the Virginia Coastal Information Program, a wave climatology project was initiated in 1988 with support from the National Oceanographic and Atmospheric Agency\u27s Coastal Zone Management Program administered by the Virginia Council on the Environment. Directional wave observations were begun on a seasonal schedule (fall, winter, spring) at a single station location near the Thimble Shoal Light in lower Chesapeake Bay. In 1993, a one-year cooperative agreement between the United States of America and the Commonwealth of Virginia permitted a second wave station to be operated at the entrance to the Thimble Shoal Channel, a major navigational route in the lower bay (Figure 1). Simultaneous wave observations obtained at these two stations, Thimble Shoal Light (TSL) and Thimble Shoal Entrance (TSE), were presented in an earlier report (Boon and Hepworth, 1993). The present report contains a description of the observations and analyses performed at the TSL wave station, the sole station in operation during the 1993-1994 season

    Systems Development of a Two-Axis Stabilised Platform to Facilitate Astronomical Observations from a Moving Base

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    This project aimed to design, simulate, and implement a two-axis inertially stabilised platform (ISP) for use in astronomical applications. It aimed to approximate the stabilisation of a Meade ETX-90 3.5" compound telescope at low-cost using a mechanical assembly designed to geometrically and inertially model the telescope. A set of system specifications was developed to guide design decisions and to provide an analysis framework against which the performance of the implemented system was compared. The electro-mechanical structure of the ISP was designed and manufactured, the associated electrical systems were specified and configured, an image processing script capable of detecting and locating the centre of the Moon in a camera field-of-view was written, a complete simulation model for the system was developed and used to design various classical controllers for the ISP control system. These controllers were implemented on a STM32F051 microcontroller and a user interface was written in LabVIEW to facilitate intuitive user control of the system and perform datalogging of the system runtime data.Comment: 2019 Southern African Universities Power Engineering Conference/Robotics and Mechatronics/Pattern Recognition Association of South Africa (SAUPEC/RobMech/PRASA

    Chesapeake Bay Wave Climate : Wolf Trap Wave Station, Report and Summary of Wave Observations November 6, 1989 through August 2, 1990

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    The Virginia Institute of Marine Science, in cooperation with the Virginia Department of Conservation and Recreation, Division of Soil and Water Conservation, has identified as one of its major goals the systematic study of hydrodynamic processes that affect recreational, shoreline and benthic resources in the coastal zone of the Commonwealth. In pursuit of that goal, a long-term study of the wave climate in the Virginia portion of Chesapeake Bay was initiated in 1988 with support from the National Oceanographic and Atmospheric Administration through the Coastal Zone Management Program administered by the Virginia Council on the Environment (Grant No. NA89AA-D-CZ134)

    Laparostomy and temporary abdominal closure outcomes in emergency non-trauma surgery and parameters affecting early definite primary fascial closure

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    BACKGROUND: The open abdomen or laparostomy is a great advance of surgery based on the concept of damage control surgery. Aim of the study is to review the laparostomy outcomes of non- trauma emergency surgery patients in a district general hospital and identify parameters affecting early definite primary fascial closure. METHODS: The records of all non-trauma emergency surgical patients who underwent laparostomy in a three-year period in a single institute were studied retrospectively. Outcomes included length of stay, morbidity, mortality, readmission rates, number of re-look operations, rate of definite primary fascial closure and time to closure. RESULTS: Thirty-two patients were included. Morbidity was 84.4% and mortality rates were 21.9% (in- Hospital), 18.8% (30-day) and 46.9% (overall). Median length of hospital stay was 22 days. Rate of primary fascial closure was 87.5% and median time to closure was two days. The number of relook operations was the only independent prognostic factor of definite early primary fascial closure, with higher rates of closure in patients with 1-2 relooks. CONCLUSIONS: Although the open abdomen has been demonstrated to improve survival, the precise role in abdominal sepsis has not been elucidated. Current consensus does not support use of open abdomen routinely, however in selected situations it becomes unavoidable. Laparostomy is a valid option in non-trauma emergency surgery and can be managed safely in a district hospital. High closure rates can be achieved if one or two re-look operations are performed with an early attempt for closure

    Cross-shoreface Suspended Sediment Transport : A Response to the Interaction of Nearshore and Shelf Processes, Fall 1994 Duck, NC Field Experiment

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    Deployment : The tripods were assembled, tested and secured onboard the RIV Sea Diver, which left the Little Creek Amphibious Base in Norfolk, Virginia early on 26 September. While underway to the deployment site, the continuous surface water conductivity and temperature survey was run and several CTD casts were made. The tripods were deployed on 26 September and secured to the sea floor with sand anchors by VIMS divers. The R/V Sea Diver then began the series of on/off shore transects at the tripod deployment site for approximately 12 hours. The vessel returned to port on 27 September . Recovery: The tripod recovery cruise began late on 21 October and repeated the underway data collection scheme of the September cruise. On October 22 divers removed the sand anchors and the tripods were recovered without incident. The on/off shore transects were repeated and transit to port occurred on 23 October

    Chesapeake Bay wave climate : Thimble Shoal light wave station, report and summary of wave observations, October 8, 1990 through August 22, 1991 and Chesapeake light tower - VIMS Star gage test measurements and evaluation, July, August, October 1991

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    This report also presents a description of a directional wave gaging system, known as a Star gage, that is designed for long-term, low-maintenance operation both within and immediately outside the Chesapeake Bay entrance area. This development was prompted by our dependence to date on the single-point, PUV-type directional wave gage described below. While ideally suited for short-term investigative studies at different sites, the PUV directional wave gage requires field service visits at monthly intervals to maintain adequate performance and uninterrupted operation. A prototype Star gage system was constructed and field tested to evaluate its potential use as a long-term and eventual real-time wave gage for the Virginia coastal environment. A test deployment of the VIMS Star gage, a 4-element pressure sensor array utilizing a star configuration (Goda, 1985) was conducted at the Chesapeake Light Tower (CLT, Fig. 1) located approximately 14 nautical miles east of the bay entrance. Results of these tests are reported in Section VII

    Chesapeake Bay wave climate : Thimble Shoals wave station, report and summary of wave observations, September 27, 1988 through October 17, 1989

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    The Virginia Institute of Marine Science, in cooperation with the Virginia Department of Conservation and Recreation, Division of Soil and Water Conservation, has identified as one of its major goals the systematic study of hydrodynamic processes that affect recreational, shoreline and benthic resources in the coastal zone of the Commonwealth. In pursuit of that goal, a long-term study of the wave climate in the Virginia portion of Chesapeake Bay was initiated in 1988 with support from the National Oceanographic and Atmospheric Administration through the Coastal Zone Management Program administered by the Virginia Council on the Environment (Grant Ho. HA88AA-D-CZ092). Past knowledge of wave properties in the Chesapeake Bay region has been conspicuous in its lack of an observational basis. Although inner shelf and deep water wave measurements have been made outside the Chesapeake Bay entrance, none of these have produced reliable directional information (Seymour et al., 1985). Therefore, before addressing certain long-term wave monitoring objectives, it was deemed essential to develop a basis for them by obtaining a representative (year-long) series of wave observations at one or more selected locations. The first of these has recently been completed for a station designated as VIMS BAY! located near Thimble Shoals to the west of the Chesapeake Bay entrance (Fig. 1). This report contains a summary of data for the initial year of continuous directional wave measurements made at the Thimble Shoals station
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