Definition

1. Noun:
   • A unit of pressure: The "bar absolute" is a specific unit for measuring pressure. It is defined as exactly equal to one dyne of force applied over an area of one square centimeter. This unit is used in scientific contexts, particularly in physics and engineering, to express absolute pressure values, meaning pressure measured relative to a perfect vacuum.

Usage Notes

• "Bar absolute" is a compound noun. The word "bar" here is a unit, and "absolute" specifies that the measurement is against an absolute zero pressure reference (a complete vacuum). It is often abbreviated as "bara" to distinguish it from "bar gauge" (barg), which measures pressure relative to atmospheric pressure.
• This term is technical and primarily used in fields like meteorology, aeronautics, and process engineering.

Examples

• Noun:
  • The pressure inside the vessel was recorded as 2.5 bar absolute.
  • Standard atmospheric pressure is approximately 1.01325 bar absolute.

Advanced Usage

• In Calculations: "Bar absolute" is crucial for calculations involving the ideal gas law or any system where the absolute pressure is a fundamental variable, not the gauge pressure.
  • For the thermodynamic model, all pressure inputs must be in bar absolute.

Variants and Related Words

• Bar (bar): A more common unit of pressure defined as 100,000 pascals. One "bar absolute" is equal to 1 bar when referring to absolute pressure.
• Pascal (Pa): The SI unit of pressure. One "bar absolute" is equal to 100,000 pascals.
• Atmosphere (atm): A unit of pressure based on Earth's atmospheric pressure at sea level. One standard atmosphere is approximately 1.01325 bar absolute.
• Bar gauge (barg): Pressure measured relative to atmospheric pressure. For example, 0 barg equals approximately 1.01325 bara at sea level.

Synonyms

• Bara: The standard abbreviation for "bar absolute."
• Absolute bar: A less common but acceptable alternative phrasing.

Related Phrases

• Absolute pressure: The general concept of pressure measured relative to a perfect vacuum. "Bar absolute" is a specific unit for expressing this concept.
  • The sensor provides a reading of absolute pressure in bar absolute.

Noun

1. the absolute unit of pressure equal to one dyne per square centimeter