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Stimuli-responsive petroleum cement composite with giant expansion and enhanced mechanical properties

Shrinkage, as an inherent property of cement during the curing process, has been a concern in the oil & gas industry for centuries. Therefore, expansive cement has been studied for many decades, primarily through incorporation of expansive additives. Nevertheless, traditional expansive additives are not able to achieve the required expansive ratio or maintain a good mechanical property for the cement composite at extreme underground condition. Accordingly, a new generation of expansive additive, which not only has the required expansion, but also work at the downhole high temperature and high pressure environment, and maintain or even enhance the mechanical property, is highly desired. In this work, a high enthalpy storage shape memory polymer (SMP) as a new class of expansive additive is investigated. It is found that the cement composite achieves 1.4% circumferential expansion by only 6% by weight of SMP additives. The compressive strength and flexural strength are also enhanced at the same time, which is hardly achievable by other expansive additives with the same concertation. Good pumpability is also proved by rheological study. The mechanism controlling the enhanced properties is reveled through morphological study and element mapping analysis at the SMP/cement interface.

36 MATERIALS SCIENCE↗

Dual-Stimuli Responsive Single-Chain Polymer Folding via Intrachain Complexation of Tetramethoxyazobenzene and β-Cyclodextrin

We synthesize and characterize a triblock polymer with asymmetric tetramethoxyazobenzene (TMAB) and β-cyclodextrin functionalization, taking advantage of the well-characterized azobenzene derivative-cyclodextrin inclusion complex to promote photoresponsive, self-contained folding of the polymer in an aqueous system. We use 1 H NMR to show the reversibility of (E)-to-(Z) and (Z)-to-(E) TMAB photoisomerization, and evaluate the thermal stability of (Z)-TMAB and the comparatively rapid acid-catalyzed thermal (Z)-to-(E) isomerization. Important for its potential use as a functional material, we show the photoisomerization cyclability of the polymeric TMAB chromophore and calculate isomerization quantum yields by extinction spectroscopy. To verify self-inclusion of the polymeric TMAB and cyclodextrin, we use two-dimensional 1 H NOESY NMR data to show proximity of TMAB and cyclodextrin in the (E)-state only; however, (Z)-TMAB is not locally correlated with cyclodextrin. Lastly, the observed decrease in photoisomerization quantum yield for the dual-functionalized polymer compared to the isolated chromophore in an aqueous solution confirms TMAB and β-cyclodextrin not only are in proximity to one another, but also form the inclusion complex.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Fisheries Technology Associates, Inc. - Sweeping CHIRPs, Looming Darkness: In-Sync Stimuli - Fish Protection Prize (Final Report)

In FY2020, the National Renewable Energy Laboratory (NREL) initiated a Prize competition with support from Pacific Northwest National Laboratory (PNNL), and sponsored by the U.S. Department of Energy Water Power Technologies Office (DOE WPTO), to support the development of innovative methods for excluding fish from water diversions and intakes: the Fish Protection Prize. Proposed solutions can include new ideas for addressing fish exclusion or improvements to existing technologies. Solutions can be applied to river and canal diversions, unscreened diversion pipes, or intakes at dams. In FY20 PNNL provided voucher support in the form of technical reviews and support, as well as graphics and presentation support, in helping the 9 finalists prepare for the Pitch Contest at the American Fisheries Society (AFS) virtual meeting. There were no subject inventions, patent applications, copyrights, and trademarks under this CRADA. The report herein provides an abstract of the presentation that the finalist presented at the American Fisheries Society virtual meeting in September 2020.

42 ENGINEERING↗