Journal ArticleDOI
Use of dynamic schlieren interferometry to study fluctuations during free diffusion.
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TLDR
A form of schlieren interferometry is used to measure the mean-squared amplitude and temporal autocorrelation function of concentration fluctuations driven by the presence of a gradient during the free diffusion of a urea solution into water.Abstract:
We used a form of schlieren interferometry to measure the mean-squared amplitude and temporal autocorrelation function of concentration fluctuations driven by the presence of a gradient during the free diffusion of a urea solution into water. By taking and processing sequences of images separated in time by less than the shortest correlation time of interest, we were able to simultaneously measure dynamics at a number of different wave vectors. The technique is conceptually similar to the shadowgraph method, which has been used to make similar measurements, but the schlieren method has the advantage that the transfer function is wave-vector independent rather than oscillatory.read more
Citations
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Journal ArticleDOI
Fourier transform light scattering of inhomogeneous and dynamic structures.
TL;DR: This work presents a novel experimental approach that combines optical microscopy, holography, and light scattering for studying inhomogeneous and dynamic media and can be regarded as the spatial equivalent of Fourier transform infrared spectroscopy.
Book ChapterDOI
Chemical Physics of Colloid Systems and Interfaces
TL;DR: In this article, the authors consider the interaction between a Particle of Immobile Surface Interacting with a Solid Wall 5.5.2 and Fluid Particles and Films of Tangentially Mobile Surfaces.
Journal ArticleDOI
Differential dynamic microscopy: a high-throughput method for characterizing the motility of microorganisms.
Vincent A. Martinez,Rut Besseling,Ottavio A. Croze,Julien Tailleur,Mathias Reufer,Jana Schwarz-Linek,Laurence G. Wilson,Laurence G. Wilson,Martin A. Bees,Wilson C. K. Poon +9 more
TL;DR: A fast, high-throughput method for characterizing the motility of microorganisms in three dimensions based on standard imaging microscopy by analyzing the spatiotemporal fluctuations of the intensity in the sample from time-lapse images and obtaining the intermediate scattering function of the system.
Journal ArticleDOI
Scattering information obtained by optical microscopy: differential dynamic microscopy and beyond.
TL;DR: A theoretical model for microscope imaging is derived that accounts for the three-dimensional nature of the sample, the arbitrary coherence properties of the light source, and the effect of the finite numerical aperture of the microscope objective and extends to the class of microscopy techniques that can be described by a linear space-invariant imaging of the density of the scattering centers, which includes, for example, dynamic fluorescence microscopy.
Journal ArticleDOI
Digital Fourier microscopy for soft matter dynamics
Fabio Giavazzi,Roberto Cerbino +1 more
TL;DR: Digital Fourier microscopy (DFM) as discussed by the authors has been proposed to study the correlation properties of the sample in the reciprocal space via spatial Fourier analysis of images collected in the real space.
References
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Journal ArticleDOI
Heterodyne near-field scattering
TL;DR: In this article, an optical technique based on the statistical analysis of the random intensity distribution due to the interference of the near-field scattered light with the strong transmitted beam is described.
Journal ArticleDOI
The spatio-temporal structure of spiral-defect chaos
TL;DR: In this paper, the authors employ the modulus squared of the space-time Fourier transform of time series of two-dimensional shadowgraph images to construct the structure factor S(k, ω).
Journal ArticleDOI
A schlieren method for ultra-low–angle light scattering measurements
TL;DR: In this article, a self-calibrating optical technique was proposed to perform absolute measurements of scattering cross-sections for the light scattered at extremely small angles, using a very simple optical layout similar to that used for the schlieren method, a technique traditionally used for mapping local refraction index changes.
Journal ArticleDOI
Two experimental tests of a fluctuation-induced first-order phase transition: intensity fluctuation microscopy at the nematic-smectic-A transition.
TL;DR: It is shown that the NA transition in 4'-n-octyl-4-cyanobiphenyl (8CB) is clearly first order, contrary to calorimetric studies but in agreement with conclusions drawn from front-velocity measurements.
Journal ArticleDOI
Diffusion in a different direction
TL;DR: In this article, it was shown that diffusive motion can cause large fluctuations in the process of mixing two fluids in a free fall environment, and that these fluctuations will be larger still in a low gravity environment, so experiments in free fall may find some manifestations of diffusive motions to be profoundly changed.