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Record Details

Record 80 of 16775
A novel technique for response function determination of shear sensitive cholesteric liquid crystals for boundary layer investigations
External Online Source: doi:10.1063/1.1142438
Author and Affiliation:
Parmar, D. S.(NASA Langley Research Center, Hampton, VA, United States)
Abstract: A description of the design and setup of an experimental technique for measurement of the response function in shear sensitive liquid crystals has been reported. Utilizing the selective reflection characteristics of cholesteric liquid crystals, the method is capable of measuring the delay, rise, and relaxation times in response to a given dynamic shear stress as a function of the wavelength of the incident light. Application of a step input shear stress results in a liquid crystal time response that can be described as consisting of an initial delay, a shear induced helix deformation, and a relaxation to the initial state through diffusion processes. The method has been used for quantitative calibration of a shear sensitive liquid crystal by observing the peak in reflected light intensity, at a given wavelength, as a function of the shear stress.
Publication Date: Jun 01, 1991
Document ID:
19910055731
(Acquired Nov 28, 1995)
Accession Number: 91A40354
Subject Category: INSTRUMENTATION AND PHOTOGRAPHY
Document Type: Journal Article
Publication Information: Review of Scientific Instruments (ISSN 0034-6748); 62; 1596-160
Publisher Information: United States
Financial Sponsor: NASA; United States
Organization Source: NASA Langley Research Center; Hampton, VA, United States
Description: 13p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: LIQUID CRYSTALS; LUMINOUS INTENSITY; SHEAR PROPERTIES; SHEAR STRESS; BOUNDARY LAYERS; OPTICAL MEASUREMENT; REFLECTANCE; SHEAR FLOW; SURFACE PROPERTIES
Imprint And Other Notes: Review of Scientific Instruments (ISSN 0034-6748), vol. 62, June 1991, p. 1596-1608.
Availability Source: Other Sources
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