Dynamic mechanical measurements, definition

ASTM D4092-83a, Standard Definitions and Descriptions of Terms Relating to Dynamical Mechanical Measurements on Plastics, Annual Book ASTM Standards (1989), Vol. 8.03, p. 334. 

Standard Definitions and Descriptions of Terms Relating to Conditioning, E41, Annual book of ASTM Standards, American Society for Testing and Materials Standard Definitions and Descriptions of Terms Relating to Dynamic Mechanical Measurements on plastics, D4092, Annual book of ASTM Standards, American Society for Testing and Materials... 

ASTM D4092-01 (ISO 6721) is entitled Standard Terminology for Dynamic Mechanical Measurements on Plastics, DoD Adopted. It contains descriptions of the technical terms for dynamic mechanical property measurements on plastics including solids, melts, and solutions. It is also relatable to ISO 472 Definitions and certain items in ISO 6721-01, Plastics—Determination of Dynamic Mechanical Properties, Part 1, General Principles. Other ASTM/ISO standard test methods for dynamic mechanical analyses are... 

NOTE For all the techniques listed here, the terminology defines the property that is measured, and each definition may be completed by adding... as a function of temperature . For example dynamic mechanical analysis (DMA), n- a technique where moduli are determined as a function of temperature. 

The quantities E and G refer to quasi-static measurements. When cyclic motions of stress and strain are involved, it is more convenient to use dynamical mechanical moduli. The complex Young s modulus is then defined as = " + iE", where E is the storage modulus and " the loss modulus. The storage modulus is a measure of the energy stored elastically during deformation the loss modulus is a measure of the energy converted to heat. Similar definitions hold for G, J, and other mechanical properties. 

The quantities E and G refer to quasistatic measurements. When cyclical or repetitive motions of stress and strain are involved, it is more convenient to talk about dynamic mechanical moduli. The complex Young s modulus has the formal definition... 

The time difference (delay) between the measured quantity and the measurement result is called the inertial error. A definition- is the error due to iner tia (mechanical, thermal, etc.) of the parts of a measuring instrument. In ventilation equipment the critical component in the measuring chain, from the dynamic point of view, is often the sensor or the measuring transducer (probe). 

As with most questions on particle size, the answer is very dependent on the definition used and the experimental technique. For a dynamic aerosol cloud, the correct definition is the aerodynamic particle size, which is the diameter of an equivalent sphere of unit density. An equivalent sphere is a conventional assumption in particle sizing, but for the aerodynamic size, the density is included to account for the momentum of the particle, i.e., both mass and velocity are important. The technique chosen for measurement must include these parameters, and impaction is the normally chosen technique, which also reflects the major deposition mechanism in the lung. A schematic of an impaction plate is given in Figure 10.3. 

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