Linear-dichroic infrared spectroscopy—Validation and experimental design of the new orientation technique of solid samples as suspension in nematic liquid crystal

2007 ◽  
Vol 67 (1) ◽  
pp. 66-75 ◽  
Author(s):  
B.B. Ivanova ◽  
V.D. Simeonov ◽  
M.G. Arnaudov ◽  
D.L. Tsalev
Keyword(s):  
Infrared Spectroscopy ◽  
Liquid Crystal ◽  
Experimental Design ◽  
Nematic Liquid Crystal ◽  
Solid Samples ◽  
Orientation Technique

Direct Full Surface Skin Friction Measurement Using Nematic Liquid Crystal Techniques

1998 ◽  
Vol 120 (4) ◽  
pp. 847-853 ◽  
Author(s):  
D. R. Buttsworth ◽  
S. J. Elston ◽  
T. V. Jones
Keyword(s):  
Mathematical Model ◽  
Liquid Crystal ◽  
Skin Friction ◽  
Nematic Liquid Crystal ◽  
Measurement Techniques ◽  
Surface Measurement ◽  
Calibration Data ◽  
Surface Shear Stress ◽  
Orientation Technique ◽  
Friction Measurements

New techniques for the direct measurement of skin friction using nematic liquid crystal layers are demonstrated. Skin friction measurements can be made using a molecular rotation time technique or an equilibrium orientation technique. A mathematical model describing the molecular dynamics of the nematic liquid crystal layer has been introduced. Theoretical results from the proposed mathematical model are in excellent agreement with the current experimental measurements. It is thus demonstrated that the present model captures the essential physics of the nematic liquid crystal measurement techniques. Estimates based on the variance of the liquid crystal calibration data indicate that skin friction measurements to within ±4 percent should certainly be possible. The techniques offer the considerable advantage of simplicity, without any compromise on the accuracy, relative to other surface shear stress measurement techniques. The full surface measurement capacity of the equilibrium orientation technique is demonstrated by measuring the skin friction distribution around a cylindrical obstruction in a fully developed laminar flow.

Direct Full Surface Skin Friction Measurement Using Nematic Liquid Crystal Techniques

1997 ◽  
Author(s):  
D. R. Buttsworth ◽  
S. J. Elston ◽  
T. V. Jones
Keyword(s):  
Mathematical Model ◽  
Liquid Crystal ◽  
Skin Friction ◽  
Nematic Liquid Crystal ◽  
Measurement Techniques ◽  
Surface Measurement ◽  
Calibration Data ◽  
Surface Shear Stress ◽  
Orientation Technique ◽  
Friction Measurements

New techniques for the direct measurement of skin friction using nematic liquid crystal layers are demonstrated. Skin friction measurements can be made using a molecular rotation time technique or an equilibrium orientation technique. A mathematical model describing the molecular dynamics of the nematic liquid crystal layer has been introduced. Theoretical results from the proposed mathematical model are in excellent agreement with the current experimental measurements. It is thus demonstrated that the present model captures the essential physics of the nematic liquid crystal measurement techniques. Estimates based on the variance of the liquid crystal calibration data indicate that skin friction measurements to within ± 4 % should certainly be possible. The techniques offer the considerable advantage of simplicity, without any compromise on the accuracy, relative to other surface shear stress measurement techniques. The full surface measurement capacity of the equilibrium orientation technique is demonstrated by measuring the skin friction distribution around a cylindrical obstruction in a fully developed laminar flow.

scholarly journals Solid state linear-dichroic infrared (IR-LD) spectroscopic characterization of α-and β-glycine polymorphs

2006 ◽  
Vol 4 (1) ◽  
pp. 111-117 ◽  
Author(s):  
Bojidarka Ivanova
Keyword(s):  
Liquid Crystal ◽  
Solid State ◽  
Structural Analysis ◽  
Nematic Liquid Crystal ◽  
Spectroscopic Analysis ◽  
Spectroscopic Characterization ◽  
State Orientation ◽  
Orientation Technique

AbstractIR-LD spectroscopic analysis using nematic liquid crystal suspension as a solid-state orientation technique and the reducing-difference procedure for polarized spectra interpretation are applied to the α-and β-polymorphs of glycine. Both structural analysis and detailed IR band assignments were carried out.

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