No, the bottom ring is the oil ring. It wipes excess oil off the cylinder wall.
compression
compression
compression
compression
compression
compression rings on pistons are worn out or broken
The DNJ ring spec. information, printed on each compression ring (located next to the piston ring gap), is installed facing the top of the piston for both the top (#1) and middle (#2) compression piston ring slots. The oil control ring can be installed just like any other oil control ring in the bottom (#3) piston ring slot.
Compression and tension occur in opposite side of the footing relative to position. So, at a spread ftg or pile cap, the top reinforcing will be in tension and the bottom compression. At the midspan, between spread ftgs or pile caps, the tension will occur in the bottom and compression in the top. Rebar lap splices usually occur in the compression points, so bottom lap at spread ftgs and top at midspans. Also, details will typical have additional rebar at the points of maximum tension so at the top over supports and bottom at midspans. This though should be confirmed with the Engineer of Record on any project, as assumptions can change project to project. But this is the general concept.
A typical spark ignition (SI) engine usually has three piston rings per cylinder. These consist of one compression ring at the top, one oil control ring at the bottom, and sometimes a second compression ring in the middle. This configuration helps optimize compression, control oil consumption, and reduce emissions. However, the exact number of rings can vary depending on the engine design and manufacturer.
The DNJ ring spec. information, printed on each compression ring (located next to the piston ring gap), is installed facing the top of the piston for both the top (#1) and middle (#2) compression piston ring slots. The oil control ring can be installed just like any other oil control ring in the bottom (#3) piston ring slot.
Most commonly the bottom ring will be the Oil Controlring.(Control added by amclaussen.)Oil control ring is correct. It is used to keep the cylinder lubricated as the piston goes up and down. The first two top rings are for compression. However, the 2nd from the top ring is also a wipper ring. Used to keep oil from getting into the combustion chamber.(~Decker)
Bottom steel in a structural element, such as a beam or slab, is considered to be in compression because it is positioned to resist compressive forces that occur during loading. When a load is applied, the top portion experiences tension, while the bottom portion experiences compression due to the bending of the element. This distribution of forces helps maintain the structural integrity as loads are transferred through the material. Therefore, the bottom steel reinforces the element against potential buckling or failure under compressive stresses.