Natural-gas pipelines cannot be used because hydrogen makes the steel tubing brittle and attacks the welds.

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Cycling's innovations, including spokes, pneumatic tyres, ball bearings, steel tubing and differential gears, were soon borrowed by the motor industry.

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The structure is made of steel tubing and the body of aluminum.

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And even the Unabomber--in riding his bicycle--enjoyed the labor of some fellow who rolled the steel tubing andanother guy who glued the tires.

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Mine engineers decided to encase just the top part of the shaft with steel tubing to prevent rockfalls and further collapses during the extraction process.

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