Unpopulated boards are usually bare-board tested for "shorts" and "opens". A short is a connection between two points that should not be connected. An open is a missing connection between points that should be connected. For high-volume production a fixture or a rigid needle adapter is used to make contact with copper lands on the board. Building the adapter is a significant fixed cost and is only economical for high-volume or high-value production. For small or medium volume production flying probe testers are used where test probes are moved over the board by an XY drive to make contact with the copper lands. The CAM system instructs the electrical tester to apply a voltage to each contact point as required and to check that this voltage appears on the appropriate contact points and only on these.
What system tells the flying probe where to go and what to do?
CAM system

After the decline of Aksum, the Eritrean highlands were under the domain of Bahr Negash ruled by the Bahr Negus. The area was then known as Ma'ikele Bahr ("between the seas/rivers," i.e. the land between the Red Sea and the Mereb river). It was later renamed under Emperor Zara Yaqob as the domain of the Bahr Negash, the Medri Bahri ("Sea land" in Tingrinya, although it included some areas like Shire on the other side of the Mereb, today in Ethiopia). With its capital at Debarwa, the state's main provinces were Hamasien, Serae and Akele Guzai.
What were the main provinces of Medri Bahri?
Hamasien, Serae and Akele Guzai

Most ingested uranium is excreted during digestion. Only 0.5% is absorbed when insoluble forms of uranium, such as its oxide, are ingested, whereas absorption of the more soluble uranyl ion can be up to 5%. However, soluble uranium compounds tend to quickly pass through the body, whereas insoluble uranium compounds, especially when inhaled by way of dust into the lungs, pose a more serious exposure hazard. After entering the bloodstream, the absorbed uranium tends to bioaccumulate and stay for many years in bone tissue because of uranium's affinity for phosphates. Uranium is not absorbed through the skin, and alpha particles released by uranium cannot penetrate the skin.
What happens to a majority of ingested uranium?
excreted