helicoid

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helicoid

[′hel·ə‚kȯid]
(invertebrate zoology)
Of a gastropod shell, shaped like a flat coil or flattened spiral.
(mathematics)
A surface generated by a curve which is rotated about a straight line and also is translated in the direction of the line at a rate that is a constant multiple of its rate of rotation.
References in periodicals archive ?
It should be mentioned that no helicoidal instability was found for all experiments on the L-PP, LCP-PP, and their blends, even though FLH fluctuations were observed for most unstable bubbles.
Sperm packages (preserved in 80% ethanol): "head" portion visible by refringence as a darker area on the anterior third of the package, helicoidal in shape; medially corrugated; "tail" straight, becoming acute posteriorly, showing small granulations (some packages stick to each other at this point).
An immunoassay for type 1 collagen a1 helicoidal peptide 620-633, a new marker of bone resorption in osteoporosis.
Axial propagation in general helicoidal bianisotropic media.
The tangential position of the air inlet pipe gave the air flow a helicoidal movement from the top to the bottom of the cell to ensure the aerosol homogeneity.
Heliflu turbine flow meters have a two-blade monoblock impeller with a helicoidal free-running rotor that lies axially in the meter body.
At each end, helicoidal ramps, whose centres are a little over 500 m apart, took cars up to and down from the roof.
species such as radish (Newcomb & Bonnett, 1965; Seagull & Heath, 1980a), Lepidium sativum, and several others (Emons, 1987) have a net axial orientation, whereas species such as onion, Urtica dioica, and Equisetum have a helicoidal pattern (Lloyd, 1983; Emons, 1982, 1987; Emons & Wolters-Arts, 1983; Emons & van Maaren, 1987; van Amstel & Derksen, 1993).
By this I am not trying to say that the author of Avalovara was a follower of the esoteric doctrines but simply that in them he found an effective metaphor to express the obscure ties between man and cosmos, ties which, from beginning with its palindromic and helicoidal structure, that most singular novel was attempting to represent.
From the use-wear of teeth, it appears that the diet includes enough abrasive material to wear the teeth flat, as opposed to helicoidal or other wear.
Helicoidal extrusion and melt fracture defects appeared only in the polyolefins beyond shear rates of 3000 [s.