A few miles outside this small college town in New Hampshire, a number of engineers and research scientists are throwing cold water - and coming up with a batch of new ideas.
What they're doing, for example, is spraying helicopter blades or navigation locks with water. And that gives them new ideas on how to control ice accumulation. That's the sort of research undertaken by some 100 specialists here at the Cold Regions Research and Engineering Laboratory.
CRREL is a federal laboratory operated by the US Army Corps of Engineers entrusted with the chilling task of studying the environmental conditions of the world's cold regions. Chemists, biologists, geologists, glaciologists, meteorologists, and engineers here then try to provide useful information to the military personnel and civilians who live and work in these areas, which cover nearly half of the Northern Hemisphere. ''Good, solid research can answer a lot of questions,'' says Col. Wayne A. Hanson, CRREL's commander and director.
Some of the questions the laboratory has answered recently include:
* How to reduce icing on the external fuel tank of the space shuttle during launch.
* How to locate the flight data recorders from the Air Florida crash in the Potomac River last year with an experimental radar system.
* How to use snow as an effective fortification against small-arms fire.
* How to keep navigation locks free of ice using underwater air bubblers.
* How to keep ice from accumulating on ship superstructures, helicopter blades, and antennas.
* How to improve paving and pothole repair at low temperatures. (Some 35,000 ''Pothole Primers'' were distributed last year around the country.)
Although most of the research at CRREL is intended for military use, Colonel Hanson says the unclassified results are available to any federal, state, or local government. The labs will also undertake certain research projects for private industry - as long as there is no comparable facility available. The published research reports in CRREL's library are free, since its $16 million budget is funded by various government agencies.
The laboratory's scientists and engineers conduct their research at a 21-acre facility just north of Hanover. The main laboratory building contains 24 cold-room labs that can be frozen to a frosty minus 30 degrees C. or below. This is where ice crystals, centuries-old ice cores from the South Pole, and mechanical properties of snow and ice are tested. There are also sophisticated electronic, physics, and chemistry labs with special equipment for sub-zero research.
Since various forms of ice - such as snow ice, sea ice, lake ice, and river ice - pose a perennial problem for shipping and other marine activity, a huge $9 million refrigerated ice engineering laboratory approximates freeze-up conditions using scale models of waterways.
In one area of the building, criss-crossed with huge blue and yellow pipes carrying the water and the ammonia refrigerant, engineers have constructed a scale model of a section of the Ottauquechee River in Vermont from a topographical map and careful on-site measurements.
The 184-foot river section is modeled out of sand, covered with a layer of concrete, and then painted with epoxy resin to keep it from breaking under extreme temperature fluctuations. Shore, flood plain, and waterway are bright yellow, green, and a brilliant blue, respectively, for good photographic resolution.
Darryl Calkins, a CRREL research scientist in charge of refrigerated hydraulic model studies, describes a typical project simulating freeze-up conditions that might eventually damage a river shoreline:
''As the air temperature is brought down with the refrigerant, and the flow of the water is properly scaled to the model value, we monitor the 'decay' of the water temperature. As it gets close to zero degrees C., ice is produced is some areas. The water then is supercooled - below the freezing point. It may take one, two, or three hours. We watch to see how fast shore ice grows and take WSmeasurements of the thickness.'' The principles from this type of experiment can then be applied to comparable conditions outside the lab.
The scientists also use a 120-foot flume to test the development of frazil ice, a particularly destructive form of ice crystal that travels in the flow of extremely cold water and sticks to any obstacle such as industrial intake pipes. Frazil ice can also accumulate to great depths beneath surface ice and cause massive flooding when the river ice thaws. ''Think of a bottle of pop left too long in the refrigerator,'' Colonel Hanson says; ''when you pop the cap you get a bottle of slush. That's what frazil ice is like. In a river you may end up with 14 to 15 feet of ice below the surface.''
An experimental ice boom designed by CRREL engineers is already stretched across a section of the Allegheny River to help prevent flooding at Oil City, Pa.
CRREL has also closely monitored work along the Alaska pipeline and the effects of building haul roads in permafrost. Engineers are now designing insulated roads and airfields in these cold regions that will not destroy the permafrost.