Probing the Viscoelasticity of Collagen Solutions via Optical-Tweezers-Based Microrheology

2012 ◽  
Vol 1465 ◽  
Author(s):  
Marjan Shayegan ◽  
Nancy R. Forde
Keyword(s):  
Optical Tweezers ◽  
Polyethylene Oxide ◽  
Short Range ◽  
Surrounding Medium ◽  
Physical Property ◽  
Thermal Fluctuations ◽  
High Frequencies ◽  
Analysis Techniques ◽  
Measurement And Analysis ◽  
Structure Of Proteins

ABSTRACTHow the molecular structure of proteins in solution correlates with the mechanical properties of the solution at different length scales is not known. Using optical-tweezers based microrheology, we investigate a key physical property, viscoelasticity, of collagen solutions. To do this, we measure short-range thermal fluctuations of probe particles to obtain elastic and viscous moduli of their surrounding medium, and validate our measurement and analysis techniques using the previously studied system of polyethylene oxide. Probing the concentration dependence of viscoelasticity, we find that collagen solutions exhibit elasticity of comparable strength to viscosity when the concentration reaches ∼5 mg/ml. We also find that the presence of telopeptides alters the viscoelasticity of collagen solutions, particularly at high frequencies

scholarly journals Measurement and analysis of gas-puff density distributions for plasma radiation source z pinches

2001 ◽  
Vol 19 (4) ◽  
pp. 579-595 ◽  
Author(s):  
D. MOSHER ◽  
B.V. WEBER ◽  
B. MOOSMAN ◽  
R.J. COMMISSO ◽  
P. COLEMAN ◽  
...  
Keyword(s):  
Radiation Source ◽  
Gas Flow ◽  
Initial Density ◽  
High Sensitivity ◽  
Plasma Radiation ◽  
Analysis Techniques ◽  
Density Distributions ◽  
Radiation Properties ◽  
Wide Range ◽  
Measurement And Analysis

High-sensitivity interferometry measurements of initial density distributions are reviewed for a wide range of gas-puff nozzles used in plasma radiation source (PRS) z-pinch experiments. Accurate gas distributions are required for determining experimental load parameters, modeling implosion dynamics, understanding the radiation properties of the stagnated pinch, and for predicting PRS performance in future experiments. For a number of these nozzles, a simple ballistic-gas-flow model (BFM) has been used to provide good physics-based analytic fits to the measured r, z density distributions. These BFM fits provide a convenient means to smoothly interpolate radial density distributions between discrete axial measurement locations for finer-zoned two-dimensional MHD calculations, and can be used to determine how changes in nozzle parameters and load geometry might alter implosion dynamics and radiation performance. These measurement and analysis techniques are demonstrated for a nested-shell nozzle used in Double Eagle and Saturn experiments. For this nozzle, the analysis suggests load modifications that may increase the K-shell yield.

scholarly journals Attenuation of sound in glacier ice from 2 to 35 kHz

2019 ◽  
Vol 13 (4) ◽  
pp. 1381-1394 ◽  
Author(s):  
Alexander Meyer ◽  
Dmitry Eliseev ◽  
Dirk Heinen ◽  
Peter Linder ◽  
Franziska Scholz ◽  
...  
Keyword(s):  
Physical Property ◽  
Sound Waves ◽  
Attenuation Length ◽  
Low Frequencies ◽  
Acoustic Damping ◽  
High Frequencies ◽  
Systematic Uncertainties ◽  
Glacier Ice

Abstract. The acoustic damping of sound waves in natural glaciers is a largely unexplored physical property that has relevance for various applications. We present measurements of the attenuation of sound in ice with a dedicated measurement setup in situ on the Italian glacier Langenferner from August 2017. The tested frequency ranges from 2 kHz to 35 kHz and probed distances between 5 m and 90 m. The attenuation length has been determined by two different methods including detailed investigations of systematic uncertainties. The attenuation length decreases with increasing frequencies. Observed values range between 13 m for low frequencies and 5 m for high frequencies. The presented results improve in accuracy with respect to previous measurements. However, the observed attenuation is found to be remarkably similar to observations at very different locations.

scholarly journals Influence of Vaned Diffuser on Dangerous Blade Vibration due to Blade Flow Interactions in a Centrifugal Compressor

1995 ◽  
Author(s):  
D. Jin ◽  
Z. Jiang ◽  
H. Hasemann ◽  
U. Haupt ◽  
M. Rautenberg
Keyword(s):  
Centrifugal Compressor ◽  
Quantitative Estimate ◽  
Blade Vibration ◽  
Space Length ◽  
Vaned Diffuser ◽  
Analysis Techniques ◽  
Flow Interaction ◽  
Measurement And Analysis ◽  
Flow Interactions ◽  
Mechanism Of Interaction

Influence of diffuser vane position on dangerous blade vibration due to blade flow interactions at part load operating condition was investigated in a centrifugal compressor. By means of some measurement and analysis techniques a mechanism of interaction between blade vibration and circumferential flow condition in the impeller with vaned diffuser was determined, which is a cause of dangerous blade vibration in resonance. Experiments for the compressor with different radial diffuser positions have been performed to reduce the effect of the blade flow interaction and the dangerous blade vibration A quantitative estimate of the influence of vaneless space length between diffuser and impeller on the blade flow interaction was made. An optimal diffuser position with lower blade vibration and higher compressor characteristics was determined.

Erratum: Lingual-Palatal Pressure Measurement and Analysis Techniques

1976 ◽  
Vol 19 (1) ◽  
pp. 191-191
Author(s):  
Herbert A. Leeper ◽  
Franklin J. Appl
Keyword(s):  
Pressure Measurement ◽  
Analysis Techniques ◽  
Measurement And Analysis ◽  
Following Error

In the September 1975 issue, the article by Herbert A. Leeper, Jr., and Franklin J. Appl, “Lingual-Palatal Pressure Measurement and Analysis Techniques,” contains the following error. Page 591, paragraph 3, formula (4) should read q   =   2   ( aH   +   β ) ab

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