at circumferential gaps, such as between a machine housing and a rotor, around a rotary shaft of the engine, and between two spaces having different fluid pressure within the engine. In turbine engines, the fluid pressure within the system, (which may be either liquid or gas) is greater than the discharge pressure (the pressure outside the area of the engine housing, toward which the fluid will tend to leak), thus creating a pressure differential in the system. As used herein, the system pressure side of is referred to as the high pressure side, while the discharge pressure side is referred to as the low pressure side.
Both carbon segmented seals and brush seals wear with time, and as they wear their performance degrades, as known to those of skillMelvin R. Jones, Construction Engineer with Bechtel Corp.

Melvin R. Jones, 57, a construction engineer for the Bechtel Corp. since 1969, died yesterday at the Southern Maryland Hospital Center in Clinton. He had suffered from cancer.

He was chief of the firm's soil and concrete testing laboratory in Seat Pleasant, where work is being done in connection with Metro construction.

Mr. Jones was born in Lancaster, Pa. He attended Pennsylvania State University. During World War II, he served with the U.S. Army in England and France.

After the war, he returned to Lancaster, where he worked for a railroad, owned and operated a service station and then became a civilian employe of the Army Engineer Corps. He worked for the Army Engineers in Marquette, Mich., for several years before transferring to Washington.

A