Hardness Hardness Hardness is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. Some materials (e.g. metals) are harder than others (e.g. plastics, wood). Macroscopic hardness is generally characterized by strong intermolecular bonds, but the behavior of solid materials under force is complex; therefore, there are different measurements of hardness: "scratch hardness", "indentation hardness", and "rebound hardness". Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity. Common examples of hard matter are ceramics, concrete, certain metals, and superhard materials, which can be contrasted with soft matter. There are three
Les Janka Legislative and Public Affairs in 1974. He moved to the Pentagon in 1976 as Deputy Assistant Secretary of Defense for Near Eastern and African Affairs. Between 1978 and 1982, he worked for DGA International, a consultant assisting European corporations in marketing advanced military technology to the Pentagon. In 1984, after serving in the White House as Deputy Press Secretary for Foreign Affairs under President Ronald Reagan, he founded the Council for American-Saudi Dialogue, a foreign policy lobbying and public affairs consulting firm. Les Janka Leslie A. Janka is President-Saudi Arabia for Quincy International LLC, resident in Riyadh Saudi Arabia.. He