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This formula is not applicable to airborne particles. The four categories of TLVs for chemical substances are defined: Threshold limit value − time-weighted average (TLV-TWA): The average exposure on the basis of a 8 hours per day, 40 hours per week work schedule.
The residence time of a fluid parcel is the total time that the parcel has spent inside a control volume (e.g.: a chemical reactor, a lake, a human body).The residence time of a set of parcels is quantified in terms of the frequency distribution of the residence time in the set, which is known as residence time distribution (RTD), or in terms of its average, known as mean residence time.
In practice, four averages are used, representing the weighted mean taken with the mole fraction, the weight fraction, and two other functions which can be related to measured quantities: Number average molar mass (M n), also loosely referred to as number average molecular weight (NAMW).
Germane is the chemical compound with the formula Ge H 4, ... and set the occupational exposure threshold limit value at 0.2 ppm for an 8-hour time weighted average. ...
In chemistry, the molar mass (M) (sometimes called molecular weight or formula weight, but see related quantities for usage) of a chemical compound is defined as the ratio between the mass and the amount of substance (measured in moles) of any sample of the compound. [1] The molar mass is a bulk, not molecular, property of a substance.
Relative atomic mass is determined by the average atomic mass, or the weighted mean of the atomic masses of all the atoms of a particular chemical element found in a particular sample, which is then compared to the atomic mass of carbon-12. [10] This comparison is the quotient of the two weights, which makes the value dimensionless (having no ...
The relative atomic mass (a weighted average, weighted by mole-fraction abundance figures) of these isotopes is the atomic weight listed for the element in the periodic table. The abundance of an isotope varies from planet to planet, and even from place to place on the Earth, but remains relatively constant in time (on a short-term scale).
A time-weighted average is any of the following: Permissible exposure limit, a legal limit in the United States for exposure of an employee to a chemical substance or physical agent such as loud noise. Time-weighted average price, the average price of a security over a specified time.