A pyroclastic flow (also known scientifically as a pyroclastic density current) is a fast-moving current of hot gas and rock (collectively known as tephra), which reaches speeds moving away from a volcano of up to 700 km/h (450 mph).The gas can reach temperatures of about 1,000 Â°C (1,830 Â°F).Pyroclastic flows normally hug the ground and travel downhill, or spread laterally under gravity. Their speed depends upon the density of the current, the volcanic output rate, and the gradient of the slope.They are a common and devastating result of certain explosive volcanic eruptions.yroclastic flows normally hug the ground and travel downhill, or spread laterally under gravity. Their speed depends upon the density of the current, the volcanic output rate, and the gradient of the slope.
Optimal Reading. An optimal reading is considered anything lower than 120/80. The actual number of 120/80 is not considered perfect--but actually numbers lower are considered to be optimal. For example, someone with a blood pressure reading of 116/76 has an optimal reading.ptimal Reading. An optimal reading is considered anything lower than 120/80. The actual number of 120/80 is not considered perfect--but actually numbers lower are considered to be optimal. For example, someone with a blood pressure reading of 116/76 has an optimal reading.
So, saying that someone has an âelevated pulse pressureâ is usually the same as saying that they have an âelevated systolic blood pressure,â which is already known to be an important clinical finding requiring treatment. A person with normal blood pressure (120/80) will have a pulse pressure of 40 (120-80). But that doesnât mean that a person with a pulse pressure of 40 has normal blood pressure. Clearly, a blood pressure of 140/100 is much different than 120/80.