A-Ad

Ad-An

Ao-Az

B-Br

Br-Bz

C-Cd

Ce-Co

Co-Cz

D

E

F-Fi

Fj-Fz

G

H

I

J

K

L

M

N

O

P-Pn

Po-Q

R

S-Si

Si-Sz

T

U

V

W

X

Y

Z

API -- American Petroleum Institute - a trade association of petroleum producers, refiners, marketers, and transporters, organized for the furtherment of the petroleum industry.

API engine service categories -- gasoline and diesel engine oil quality levels established jointly by API, SAE, and ASTM, and sometimes called SAE or API/SAE categories; formerly called API Engine Service Classifications.

API gravity -- a gravity scale established by the American Petroleum Institute and in general use in the petroleum industry, the unit being called "the A.P.I. degree." This unit is defined in terms of specific gravity as follows:

141.5   131.5
SG
SG=Specific gravity @ 60° F/60° F

Apparent viscosity -- the observed viscosity of a non-Newtonian fluid (viscosity changes with shear rate) measured at a specific shear rate and temperature.

Ash -- a measure of the amount of inorganic material in lubricating oil. Determined by burning the oil and weighing the residue. Results expressed as percent by weight.

Ash content -- a measure of the amount of inorganic material in lubricating oil. Determined by burning the oil and weighing the residue. Results expressed as percent by weight. Indication of the amount of detergent in the oil.

Asperities -- microscopic projections on metal surfaces resulting from normal surface-finishing processes. Interference between opposing asperities in sliding or rolling applications is a source of friction, and can lead to metal welding and scoring. Ideally, the lubricating film between two moving surfaces should be thicker than the combined height of the opposing asperities.

A.S.T.M. = American Society for Testing Materials -an organization whose purpose is to promote the knowledge of the materials of engineering and standardize specifications and testing.

Atomic absorption spectroscopy (AA) -- measures the radiation absorbed by chemically unbound atoms by analyzing the transmitted energy relative to the incident energy at each frequency. The procedure consists of diluting the fluid sample with methyl isobutyl ketone (MIBK) and directly aspirating the solution. The actual process of atomization involves reducing the solution to a fine spray, dissolving it, and finally vaporizing it with a flame. The vaporization of the metal particles depends upon their time in the flame, the flame temperature, and the composition of the flame gas. The spectrum occurs because atoms in the vapor state can absorb radiation at certain well-defined characteristic wave lengths. The wave length bands absorbed are very narrow and differ for each element. In addition, the absorption of radiant energy by electronic transitions from ground to excited state is essentially and absolute measure of the number of atoms in the flame and is, therefore, the concentration of the element in a sample.

Atomic emission spectroscopy (AE) -- this method uses flame excitation; atoms are excited from the heat of the flame to emit light. This method commonly uses a total consumption burner with a round burning outlet. A higher temperature flame than atomic absorption spectroscopy (AA) is typically used to produce excitation of analyte atoms. Since the heat of the flame excites analyte atoms, no special elemental lamps to shine into the flame are needed. A high resolution polychromator can be used to produce an emission intensity vs . wavelength spectrum over a range of wavelengths showing multiple element excitation lines, meaning multiple elements can be detected in one run. Alternatively, a monochromator can be set at one wavelength to concentrate on analysis of a single element at a certain emission line.

Automatic transmission fluid (ATF) -- a functional fluid for automatic transmissions in motor vehicles. Automatic transmission fluids must have suitable coefficient of friction, good low temperature viscosity, and antiwear properties. Other necessary properties are: high oxidation stability, anti-corrosion, anti-foaming, and compatibility with synthetic rubber seals.

Axial-load bearing -- a bearing in which the load acts in the direction of the axis of rotation.