The world is literally kept from coming apart by screws and bolts, and yet we don’t often give a thought to these mechanisms. Part of that is probably because we’ve gotten so good at making ...

If you regularly repair old machinery or other things around your home, you’re bound to run into rusted screws. As long as you keep the right tools and supplies on hand, you can undo even the ...

A screw is a type of hardware fastener that attributes its mechanical capabilities to the helical groove that extends around the circumference of the device's shank. These threads provide the friction ...

Screw pumps are rotary, positive displacement pumps that can have one or more screws to transfer high or low viscosity fluids along an axis. A classic example of screw pumps is the Archimedes screw ...

AUSICH, WILLIAM I. and KAMMER, THOMAS W. 2001. THE STUDY OF CRINOIDS DURING THE 20TH CENTURY AND THE CHALLENGES OF THE 21ST CENTURY. Journal of Paleontology, Vol. 75, Issue. 6, p. 1161.

23. What mode(s) of preservation is this (pay attention to the holes!)? What kind(s) of organisms are fossilized here? 24. These are fossils of the same kind of organism, a crinoid. Crinoids are very ...

They belong to the Echinoidea, one of the five classes of the phylum Echinodermata, the others being holothurians, crinoids, starfish and brittlestars. Like all echinoderms, echinoids have a skeleton ...