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Explanations of the physical mechanics of ice
skating have evolved over the years. From Wikipedia:
A skate can slide over ice because the ice molecules at the surface cannot properly bond with the molecules of the mass of ice beneath and thus are free to move like molecules of liquid water. These molecules remain in a semi-liquid state, providing lubrication.
It had long been believed that ice is slippery because the pressure of an object in contact with it causes a thin layer to melt. The hypothesis was that the blade of an ice skate, exerting pressure on the ice, melts a thin layer, providing lubrication between the ice and the blade. This explanation, called "pressure melting", originated in the 19th century. This, however, did not account for skating on ice temperatures lower than −3.5 °C, whereas skaters often skate on lower-temperature ice. In the 20th century, an alternative explanation, called "friction heating", was proposed, whereby friction of the material was causing the ice layer melting. However, this theory also failed to explain skating at low temperature. In fact, neither explanation explained why ice is slippery when standing still even at below-zero temperatures.
Professor Gabor Somorjai of Lawrence
Berkeley National Laboratory has studied the mechanics of skating and has found
that an ice skate blade actually glides on vertically vibrating ice molecules
that behave in a ‘liquid-like’ manner without actually melting and turning into
liquid.
Many hockey players and coaches agree that
good skating is a combination of strength and technique. But smooth skating and
puck-handling are also enabled by a device that is usually activated when no
skaters are on the ice. A resurfacing machine is used to wash the ice, shave
the surface, and leave behind a layer of water that will freeze to form a fresh
layer of ice. One of the most well-known examples in North
America of an ice resurfacing machine is the Zamboni.
In 1949, Mr. Frank Zamboni developed the
world’s first ice resurfacing machine. Based on a Jeep chassis, this machine
automatically and quickly provided all of the necessary operations required for
pristine skating ice. It also had built-in reservoirs to collect the old shaved
ice and distribute the new ice-making water.
Newer Zamboni models are available with
electric power supplied by rechargeable batteries. However, many of the Zamboni
engines are powered by gas, propane, or CNG (compressed natural gas), similar
to fork lift trucks. With an internal combustion engine, there will be an exhaust
gas flow. Because these vehicles function indoors in a populated environment,
it is important to keep the engines in good repair to minimize impact on indoor
air quality.
Nova has various gas analysis capabilities
including the gases that typically make up engine exhaust. Our 7460 Series
Portable Engine Exhaust Analyzers are available in various combinations
including O2, CO, CO2, HC, & NOx. Our customers have used this analyzer on
diesel, gasoline, propane, or natural gas powered 2 and 4 cycle engines.
The 7460 Series is a portable analyzer that
uses infrared and electrochemical sensors / detectors. Here it is in our on-line
catalog.
We aren’t engine mechanics. However, we do build
these analyzers to meet Bar 97 and ISO 3930/OIML R99, Class O specifications.
Therefore, many mechanics have effectively used this analyzer for reliable
engine tuning and emissions reduction. We have noticed that this analyzer is
also popular among equipment mechanics who work on forklifts and other non-road
vehicles such as Zambonis.
Added March 2013 - We have noticed that our
fork-lift customers frequently print on the analyzer cabinet the target gas
readings for a properly tuned engine. For example, we have a couple of units in
the Nova lab right now being calibrated for one of our customers. They have
printed the following target gas readings on the analyzer:
O2: 0.8 % to 2.0 %
CO: 0.1% to 0.8 %
CO2: more than 11.0 %
HC's: less than 200ppm
If you are in the business of tuning
engines and require analysis of engine exhaust, ask Mike or Dave for help with the 7460
Series Gas Analyzers.
If you're a Leafs fan, there may not be anything we can do to help you.
If you're a Leafs fan, there may not be anything we can do to help you.
1-800-295-3771
sales at nova-gas dot com
websales at nova-gas dot com
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