A large number 7 was painted on the tube wall to the right of the ladder.

I tried to dig my feet into the hard tube walls.

But the only answer was the echo of his own voice bouncing off the tube walls.

Yeremi could still see the tube wall quite clearly with his enhanced vision.

Here the tube wall is only a stone's throw away.

Low energy beta, which would penetrate an end window, would be stopped by the tube wall.

The heat transfer across the tube wall is back to within tolerable levels.

Reduction in the mean metal temperature of the tube walls.

The thicknesses of the water pipe and tube walls can vary.

Although the tube walls have a greater stopping power than an end window, they still allow these more energetic particles to reach the fill gas.