Fouling control is one of the critical issues in membrane filtration and plays a very important role in water/wastewater treatment. Better understanding of the underlying fouling mechanisms entails novel characterization techniques that can realize a real-time non-invasive observation and provide high resolution images recording the formation of a fouling layer . This work presents a characterization method based on optical coherence tomography (OCT), which is able to detect the internal structures and motions by analyzing the interference signals. An OCT system was incorporated with a lab-scale membrane filtration system, and the growth of the fouling layer was observed by using ...

Optical coherence tomography (OCT) is a low-coherence interferometric imaging method which was developed in the 1990s prevalently in the area of biomedical diagnostics. (1) It generates depth scans of samples in a contact-free, nondestructive manner. Having become a standard method for ophthalmologic examinations, (2, 3) within the past decade also applications outside the medical field were found, as summarized in a recent review (4) and with a special focus put on polymer science: in contrast to biological tissues, polymers usually do not contain water and therefore also light in the near-infrared (NIR) region, which otherwise would be absorbed, can be ...

The lack of an effective technique for three-dimensional flow visualization has limited the experimental exploration of the “coffee ring effect” to the two dimensional, top-down viewpoint. In this report, high-speed, cross-sectional imaging of the flow fields was obtained by using optical coherence tomography to track particle motion in an evaporating colloidal water drop. This approach enables z-dimensional mapping of primary and secondary flow fields and changes in these fields over time. These sectional images show that 1μm diameter polystyrene particles have a highly non-uniform vertical distribution with particles accumulating at both the air-water interface and water-glass interface during drop ...

We investigated the feasibility of constructing an implantable optical-based sensor for seminoninvasive continuous monitoring of analytes. In this novel sensor, analyte concentration-dependent changes induced in the degree of optical turbidity of the sensing element can be accurately monitored by optical coherence tomography (OCT), an interferometric technique. To demonstrate proof-of-concept, we engineered a sensor for monitoring glucose concentration that enabled us to quantitatively monitor the glucose-specific changes induced in bulk scattering (turbidity) of the sensor. The sensor consists of a glucose-permeable membrane housing that contains a suspension of macroporous hydrogel particles and concanavalin A (ConA), a glucose-specific lectin, that are designed ...