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Marine Electronics


October 2012 Issue

LVDT Sensors Used to Guide Replicate Deep Ice Coring System
Macro Sensors (Pennsauken, New Jersey) miniature LVDT linear position sensors served as part of a steering actuator control system that regulates the tilt of the new Replicate Ice Coring System designed for a U.S. deep ice coring project in one of the snowiest regions of the West Antarctica Ice Sheet (WAIS). The WAIS Divide project is examining the past 100,000 years of the Earth's climate history by drilling and recovering a deep ice core from the ice divide in central West Antarctica.

While an ice core 3,045 meters into the ice sheet was recovered last year, the Replicate Ice Coring System will re-enter the existing bore this December to extract additional ice related to areas of scientific interest. The device is undergoing a full system test this summer under simulated conditions. Using the electromechanical drill system, scientists hope to extract 250 meters of new ice cores, going down to depths of about 4,000 meters.

While initially following the course of the parent bore hole, the Replicate Ice Coring System will slightly alter its course to create a second path to collect ice samples. The system's drill uses two steering actuator sections to tilt itself in the parent borehole at a targeted trajectory.

Located along the shaft of the drill, the actuators apply lateral pressure against the side of the borehole to alter the orientation of the drill head. The actuators tilt and guide the drill into the replicate borehole where ice samples are collected.

Six Macro Sensors' CD Series Miniature LVDT Linear Position Sensors serve as part of the replicate actuator modules that push the drill out of the original hole at a targeted trajectory. The sensors work as part of a closed-loop system as the drill travels 2 miles deep into the ice at temperatures below '30° C. To accommodate the high pressure, the sensor case is vented to equalize pressure inside and outside the LVDT linear position sensor.

Glider Taking Measurements In Gulf Survives Hurricane Isaac
A Liquid Robotics Inc. (Sunnyvale, California) Wave Glider, G2, which was collecting ocean chemistry data in the Gulf of Mexico, weathered Hurricane Isaac in August, surviving sustained winds of 40 knots and gusts up to 74 knots.

G2, outfitted with sensors to measure water temperature, wind speeds, barometric pressure and air temperature, was moving out of the projected path when the storm changed direction and headed toward the glider. G2 remained in the area and collected data on the Category 1 hurricane, as the eye passed 60 miles east of it.

Time-lapsed maps showed a dramatic drop in water temperature, suggesting that Isaac was vacuuming the heat from the gulf.

Meanwhile east of Isaac, off the coast of Puerto Rico, another Wave Glider, Alex, was launched to support a joint project to measure hurricane intensity between Liquid Robotics and the NOAA Atlantic Oceanographic and Meteorological Laboratory. This Wave Glider could be the first to measure hurricane conditions above and below the surface of the ocean that are needed to predict hurricane strengthening.

DV Chikyu Drills to 2,466 Meters, Breaks Deep Drilling Record
The DV Chikyu in September broke the previous 2,111-meter record for deepest drilling depth and, a few days later, successfully drilled to 2,466 meters below the seafloor off Shimokita Peninsula, Japan, in the northwest Pacific Ocean.

The water depth of Site C0020 is 1,180 meters below sea level. The team, part of the Integrated Ocean Drilling Program (IODP) Expedition 337 Deep Coalbed Biosphere, obtained core samples from 2,466 meters below the seafloor. These sample materials are taken from a deeply buried coal formation for the purpose of investigating co-evolution of Earth and life.

The expedition was scheduled to continue through the end of September, but the drilling of additional deep boreholes is not planned for the remaining period, according to the Japan Agency for Marine-Earth Science and Technology (JAMSTEC).

The next scientific cruise aboard Chikyu, IODP Expedition 338 Nankai Trough Seismogenic Zone Experiment, was scheduled to start in October. That expedition will also attempt to deepen a borehole to 3,600 meters below the seafloor to investigate the deep tectonic process involved in seismogenesis.

Before Chikyu broke the record, the previous deepest hole in the history of scientific ocean drilling reached 2,111 meters into the Costa Rica Rift seafloor.

Samples collected from the target coal beds have been analyzed in the laboratory aboard Chikyu and will continue to be examined after the expedition. The research could provide new insights into the deep life associated with a hydrocarbon system in the deep-marine subsurface.

Samples From UFO-Shaped Object Are Just Rocks
Treasure hunters from Ocean X (Stockholm, Sweden) discovered an object at the bottom of the Baltic Sea last year that was likened to the Millennium Falcon from 'Star Wars' and theorized to be anything from a UFO to a remnant of Atlantis. Geologists have found samples from the site to be ordinary granite and sandstone rocks.

While exploring the Baltic Sea between Sweden and Finland in June 2011, Ocean-X's sonar picked up a strange image of a cylinder-shaped, 190-foot-diameter object at a depth of approximately 275 feet in the Baltic Sea. The Ocean-X team reported experiencing electric disturbances and anomalies with their equipment when they drew near to the object on a later visit.

After retrieving rocks from the site, Ocean X divers gave them to Volker Brüchert, an associate professor of geology at Stockholm University, according to the website Live Science. Brüchert and other experts have found the rocks to be nothing out of the ordinary.

'What has been generously ignored by the Ocean-X team is that most of the samples they have brought up from the sea bottom are granites and gneisses and sandstones,' he told the website, adding that these are the types of stones that are typical of a glacial basin such as the Baltic Sea. Br'chert hypothesizes the rocks were transported there by glacier.

The team also returned balsatic rock, which Brüchert said is not unusual, Live Science reported.


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