Editing Ovality

In [[telecommunications]] and [[fiber optics]], '''ovality''' or '''noncircularity''' is the degree of deviation from perfect circularity of the cross section of the core or cladding of the fiber.

The cross-sections of the core and cladding are assumed to a first approximation to be elliptical, and ovality is defined to be twice the third [[flattening]] of the ellipse, <math>2\frac{a-b} {a+b}</math>, where ''a'' is the length of the major axis and ''b'' is the length of the minor axis. This dimensionless quantity is between {{math|0}} and {{math|1}}, and may be multiplied by {{math|100}} to express ovality as a percentage. Alternatively, ovality of the core or cladding may be specified by a [[tolerance field]] consisting of two concentric circles, within which the cross section boundaries must lie.

In measurements, ovality is the amount of out-of-roundness of a hole or cylindrical part in the typical form of an oval.

==In chemistry==
In [[computational chemistry]], especially in [[Quantitative structure–activity relationship|QSAR]]<ref name="isbn0-582-38210-6">{{cite book | author = Leach, Andrew R. | title = Molecular modelling: principles and applications | publisher = Prentice Hall | location = Englewood Cliffs, N.J | year = 2001 | isbn = 0-582-38210-6 }}</ref> studies, ovality<ref>{{cite book |last= Hehre |first= Warren J. |author2=William Sean Ohlinger |title= Spartan'10 Tutorial and User's Guide |publisher= Wavefunction, Inc. | location = Irvine, CA|year= 2008 |isbn= 1-890661-41-4}}</ref> refers to, a measure of how the shape of a molecule approaches a [[sphere]] (at one extreme) or a [[quantum electrodynamic threshold|cigar shape]] (at the other). 
Ovality is described by a ratio of volume to area:

<math>O = \frac {A}{4\pi(\frac{3V}{4\pi})^{\frac 2 3}}</math>

where:

:O = Ovality
:A = Area
:V = Volume

The ovality of the [[Helium atom|He atom]] is '''1.0''' and that of HC<sub>24</sub>H (12 triple bonds) is '''~1.7'''.

==See also==
*[[Concentricity error]]
*[[Roundness (object)]]

==References==
<references/>

*[[Federal Standard 1037C]]

[[Category:Fiber optics]]