The field of shape memory polymers (SMPs) has been dominated by polymeric systems whose fixing mechanism is based on crystallization or vitrification of the constituent chains, rendering such systems stiff in comparison to elastomers, gels, and living tissues. Previously, we reported the synthesis and characterization of main-chain, segmented liquid crystalline elastomers (LCEs) that exhibit bo...

October 1992 nPerils of sand production. At worst, sand production threatens a well. Voids can form behind the pipe, causing formation subsidence and casing collapse. The well may also fill with sand and cease flowing. Or the surface equipment may be catastrophically damaged by erosion or plugging. For help in preparation of this article, thanks to: Bob Elder, Chevron UK Ltd., London, England; ...

This paper addresses issues in the design of wheel grousers for planetary rovers. It has been shown in prior and related work that grousers on wheel rims can improve traveling performance of rovers on loose soils. However, the main focus of these studies, so far, has been limited to straight grousers and to straight line motion of the wheels. This work extends such studies to include chevron-sh...

The reduction of phosphorus and sulfur in engine oil are the main topics of this paper. Very reproducible boundary lubrication tests were conducted as part of Design of Experiment software (DOE) to study the behavior of fluorinated catalyst iron fluoride (FeF3), and polutetrafluoroethylene or Teflon (PTFE) in developing environmentally friendly (reduced P and S) anti-wear additives for future e...