The Rockwell hardness tester to measure the hardness of metal measures resistance to penetration like the Brinell test, but in the Rockwell case, the depth of the impression is measured rather than the diametric area. With the Rockwell tester, the hardness is indicated directly on the scale attached to the machine.
(Redirected from Apache Nation) The Apache (/ÉËpÃ¦tÊiË/; French: [a.paÊ]) are culturally related Native American tribes from the Southwestern United States, and have traditionally lived in Eastern Arizona, Northern Mexico (Sonora and Chihuahua), New Mexico, West Texas, and Southern Colorado.
American ethnicity. For the article on the population of the United States, see Americans. American ethnicity or American ancestry refers to people who self-identify their ancestry as American, rather than the more common officially recognized racial and ethnic groups that make up the bulk of the American people.