Resistance total

The selection of refractories resisting total break up by thermal shock is nowadays usually based on assessment of the relevant properties. The practical tests consisting of alternate heating and cooling of specimens and of determining losses of materials due to spalling show unsatisfactory accuracy. Strength decrease determination is more suitable, but even its results show considerable scatter. 

Actually it has been known for over seventy years that certain metals and alloys, when cooled to very low temperatures (around the boiling point of liquid helium, or 4 K), lose their resistance totally. However, it is not practical to use these substances, called superconductors, for transmission of electric power because the cost of maintaining electrical cables at such low temperatures is prohibitive and would far exceed the savings from more efficient electricity transmission. 

Propofol Propofol produces anesthesia at a rate similar to that of the intravenous barbiturates, and recovery is more rapid. Propofol has antiemetic actions, and recovery is not delayed after prolonged infusion. The drug is commonly used as a component of balanced anesthesia and as an anesthetic in outpatient surgery. Propofol may cause marked hypotension during induction of anesthesia, primarily through decreased peripheral resistance. Total body clearance of propofol is greater than hepatic blood flow, suggesting that its elimination includes other mechanisms in addition to metabolism by liver enzymes. 

Columnar resistance Total resistance of a 1-square-meter column of air between the earth and the ionosphere. This is largely determined by the first few kilometers above the surface and is typically 1-2 X IQi U. 

Chipping resistance n. The abihty of a coating or layers of coatings to resist total or partial removal, usually in small pieces, resulting from impact by hard objects or from wear during service. 

Since all circuits contain resistance, total opposition to flow of ac current is dependent on the vector sum of the resistance, inductive reactance, and capacitive reactance in the circuit. This vector sum is called impedance, and is measured in ohms. 

Radial direction or ohmic resistance Total entropy or mass source or mass sink Sherwood number... 

---