Think it's cold out? Well, it's a lot colder inside, just a few minutes down the road at the U.S. Army Cold Regions Research and Engineering Laboratory.
Temperatures never exceed 20 degrees below zero in some rooms in the lab, which is located on Lyme Road past the golf course. The 300 scientists who work in the 33-acre, five-building facility are responsible for researching everything from the way ice skates slide to how to make a sliding jeep stop.
Although the lab is under the aegis of the Department of Defense and the Army Corps of Engineers, its research benefits both soldier and civilian, whether by detecting mines beneath snow and ice in Bosnia or by preventing springtime flooding in Vermont towns.
The lab was built in 1961, when it replaced two previous Army labs. The Army located the site in Hanover to help stimulate New Hampshire's economy and because of its proximity to Dartmouth. Throughout the years, the lab's scientists have taught classes at the College, and many Dartmouth graduate and undergraduate students do research there.
The physics of snow
A non-descript hallway leads to the office of one of America's preeminent snow physicist Sam Colbeck, a man who was featured in a December issue of Ski Magazine for his research on skis.
Colbeck, a former adjunct professor at the College's Thayer School of Engineering, said he studies not only skis, but also the frictional properties of snow and ice.
"One of the easiest ways to get information on how friction works with snow is by using skis," Colbeck said. Not surprisingly, Colbeck has about six pairs of skis in his office, each customized for a specific experiment. One pair is equipped with infrared sensors that measure the heat transmitted to various parts of the ski as it moves along the snow.
One of Colbeck's experiments, conducted with the help of two Dartmouth students from the Women in Science Program, disproved an age-old theory of the way ice skates slide.
Ice skates were thought to glide along a tiny trail of water melted through a process called "pressure-melting," Colbeck said. But by measuring the heat on the ice-blade interface, they found that ice beneath the blade melts because of simple friction.
Family-sized freezers
There are 24 "coldrooms" in the laboratory, each of which is the size of a dorm room. But they are a lot colder than a dorm room.
One room cooled to five degrees below zero houses ice samples from around the world. Another room, constantly twenty degrees below zero, contains ice as old as the 1960s. Scientists compare ice samples from the past and present looking for variations in composition.
To prevent themselves from becoming cryogenic samples, scientists follow safety precautions while in the coldrooms. They work in protective clothing for 20-minute shifts, followed by breaks to thaw with a warm beverage.
The 'Green Machine'
No, the "Green Machine" is not a proposed new mascot for Dartmouth. Rather, the 1977 Jeep called the "Green Machine" is an important tool for research.
Mechanical Engineer Bryon Young and others use the machine to test tire traction on various surfaces at various temperatures. A computer inside the vehicle can take a variety of measurements, one of the most important being the pressure at the tire-surface interface, Young said.
Research from the Green Machine came in handy during the Gulf War, when military vehicles had trouble moving over sand. From past research, scientists at the laboratory knew that increasing tire pressure would increase traction on the sandy terrain.
Young said scientists are designing a computer model which will allow them to test a vehicle's ability to cross terrain without using the Green Machine.
"We always try to find the most cost-effective method," he said. The lab is funded by federal tax dollars.
The lab also has an extensive concrete workshop, where scientists research different types of pavement.
Scientists test different materials like wood, tire and plastic foam, to find the mixture most resistant to the damage caused by the freezing and thawing of the winter months, Darling said.
They also test the amount of tire pressure different surfaces can withstand. With the tractor-trailer-sized Heavy Vehicle Simulator, newly-arrived from South Africa, scientists will study ways to reduce tire pressure on low-volume roads of various terrain.
Permafrost and Frost Effects
The lab also conducts important research projects in the field, one of which is a permafrost tunnel, directed by Michael Walsh '77.
Walsh said the National Science Foundation contacted the laboratory with a problem in 1992. In Arctic areas power and data lines are buried beneath snow, where they are difficult to locate and access.
Walsh's unit proposed an underground tunnel that satisfied their needs.
"The tunnel allows any type of utility to go through the enclosed area," Walsh said. "This makes it easier to maintain it, and it allows the workers to stay out of the elements."
A similar tunnel lies beneath the permafrost near Fairbanks, Alaska. Constructed in the 1960s, the lab maintains the 360-foot tunnel as an underground research laboratory, where scientists study the physical and mechanical properties of ice and frozen soils.
Behind the main building is the 29,000 square-foot Frost Effects Research Facility, which holds 12 separate test cells where scientists perform controlled experiments from 120 degrees to 35 degrees below zero.
Marie Darling, the lab's public affairs director, said the facility is used for testing the effects of cold temperatures on pavements, soils, buildings and vehicles, among other things. The facility is unique because scientists can conduct full-scale tests under completely controllable conditions year-round.
