DEPARTMENT OF DEFENSE COMBATS HYPOTHERMIA

FROM:  DEPARTMENT OF DEFENSE ARMED WITH SCIENCE WEBSITE
Written on APRIL 13, 2012 AT 7:51 AM by JTOZER
Cool Under Pressure – Using Science to Stave Off Hypothermia
By Bob Reinert for USAG-Natick Public Affairs
Seventeen years after four soldiers died from hypothermia during the final phase of Ranger School, researchers at the U.S. Army Research Institute of Environmental Medicine at Natick Soldier Systems Center continue to study how the human body cools down, in hopes of one day developing medical techniques to help prevent such tragedies.

“You can’t design possible countermeasures — pharmacological treatments, perhaps — until you know mechanisms,” said Capt. David DeGroot, Ph.D., a research physiologist in USARIEM’s Thermal and Mountain Medicine Division, who is leading the study.
“You’ve got to understand the basic mechanism before you (say), ‘Okay, now how do I target it?’

“This is going to allow us to get further insight with the actual mechanisms so that we can follow it up with, Okay, what could we possibly do in terms of an intervention to mitigate that rate of core temperature drop?”

Dr. John Castellani, serving as an Army captain with USARIEM at the time, was a member of the team that conducted the institute’s initial study at Camp Rudder on Eglin Air Force Base, Fla., soon after the February 1995 deaths. He still works at the institute as a research physiologist.

Castellani said that the original study led to adjustments to the tables Rangers use to determine what amount of exposure to cold is safe.

“The swamp portion of training takes place at the very tail end of Ranger School, so soldiers have lost a lot of muscle, fat,” Castellani said. “They’re also, during that time frame, purposefully not being fed, so they may have very little food on board, and they’re also sleep deprived a lot as part of that part of the training.”

“So we studied Ranger students who were finishing up Ranger School. We tested them immediately as they came out of the swamp.”

Castellani followed these studies with the Rangers by trying to understand how physically fatigued soldiers are more susceptible to hypothermia.

“What John found was if you exposed people to cold air after they exercised, they cooled off faster than people who were warmed up passively,” DeGroot said. “So there was something about that prior exercise that led to a faster rate of decline in core temperature, higher skin temperature, higher rate of heat transfer through the skin.

“The follow-up question was always, ‘why? What’s controlling that skin temperature? What’s the mechanism responsible for this abnormal response?’”

DeGroot and his team are studying that mechanism with the help of eight soldiers from theHuman Research Volunteer Program at NSSC, who are fitted with microdialysis fibers, muscle temperature probes and skin temperature sensors. They are then put into the 102-degree waters of an immersion tank, followed by a trip to an environmental chamber, where the air temperature is a relatively cool 66 degrees.

“Now that doesn’t sound very cold, (but) all he’s wearing is a pair of shorts and a pair of socks, and he’s at rest,” said DeGroot of one volunteer. “A normal response in the cold is that the blood vessels in the skin are going to constrict, and that’s to limit the rate of heat loss from the core out to the environment. What varies is how we warm them up prior to the cold exposure — exercise versus passive.”

The use of microdialysis fibers, implanted under the skin to gather samples, was in its “infancy” when Castellani did his study, DeGroot said. Things have changed since then.
“(We are) using some different techniques that, frankly, we didn’t have a dozen years ago,” DeGroot said. “We didn’t have the technical capability to do this study.

“This is unique. Off the top of my head, I can think of (only) six other labs in the world that use microdialysis to study the control of skin blood flow.”

With a better understanding of the human body’s response to cold, USARIEM researchers likely will be in a better position to help future soldiers ward off hypothermia.
“Everything in science is incremental,” said DeGroot, “just building off of others.”

TITANIUM AND THE U.S. NAVY

FROM:  DEPARTMENT OF DEFENSE ARMED WITH SCIENCE
Written on APRIL 12, 2012 AT 7:14 AM by JTOZER
The Strength of Titanium For The Navy
From the Office of Naval Research

Steel may have met its match.
An Office of Naval Research (ONR)-funded project will produce a full-size ship hull section made entirely with marine grade titanium using a welding innovation that could help bring titanium into future Navy ship construction.

The contractor team building this section recently completed the industry’s longest friction-stir titanium alloy welds and aims to complete the ship hull section this summer. Friction stir welds more than 17 feet long joined the titanium alloy plates for the section’s deck.

“This fast, effective friction stir weld technique is now an affordable manufacturing process that takes advantage of titanium’s properties,” said Kelly Cooper, the program officer managing the project for ONR’s Sea Warfare and Weapons Department.
What it means for the Navy

Titanium metal and its alloys are desirable materials for ship hulls and other structures because of their high strength, light weight and corrosion-resistance. If constructed in titanium, Navy ships would have lighter weight for the same size—allowing for a bigger payload—and virtually no corrosion. But because titanium costs up to nine times more than steel and is technically difficult and expensive to manufacture into marine vessel hulls, it has been avoided by the shipbuilding industry.
But perhaps not for much longer.

Researchers at the University of New Orleans School of Naval Architecture and Textron Marine and Land Systems are demonstrating the feasibility of manufacturing titanium ship hull structures. Using lower cost marine grades of titanium, they fabricated a 20-foot-long main deck panel—composed of six titanium plates, joined together by friction stir welding—as part of technology studies for an experimental naval vessel called Transformable Craft, or T-Craft.