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The study of flow dynamics in micro vessels is highly important in rheology and cardiology to enable a better understanding of the effect of blood flow on the possible rupture of atherosclerotic plaques. Doppler Optical Coherence Tomography is able to provide a very high velocity resolution down to 10 μm s-1. The technique offers the potential to achieve a more detailed analysis of the flow/vessel interactions than current clinical practice offers; allowing simultaneously high resolution imaging of the morphology and composition of the atherosclerotic plaque and of the flow velocity vectorial field distribution along the measured cross-section. We use Doppler Optical Coherence Tomography to image high-resolution one-dimensional and multi-dimensional velocity distribution profiles of Intralipid solution flowing in complex micro-channels. A set of T- and Y-shaped phantoms were built to study the interaction of the flow dynamics with different channel geometries and to map the related velocity profiles at several inlet volume flow rates. In the current report we demonstrate the possibility of the technique for quantitative observation of the turbulence of flows arising within the complex micro-channel phantoms.

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With millions of fuel storage tanks and oil pipelines installed around the world, there is inevitably frequent leakage of potentially hazardous hydrocarbons. As many of these installations are below ground, it can often be many years before the extent of the leak is discovered. We have previously reported the development of a sensor for the detection of such subterranean leaks, using infrared reflectometry to interrogate a hydrocarbon sensitive membrane. However, a single sensor cannot provide any information about the flow rate or direction of the leak. This paper describes the extension of the technology to a multi-channel distributed sensing system, using optical fibres capable of distributing the sensors over large subterranean areas. Results are reported from the evaluation of the device, which consisted of monitoring the movement of different hydrocarbons (gasoline, diesel and insulating oil) through a vertical sand-filled vessel.

It is known that glucose influences on spectral properties of blood and hemoglobin and interacts with plasma proteins and hemoglobin in erythrocytes. Changes of optical properties of blood and hemoglobin at glucose concentration within physiological level are important for diagnosis and monitoring of diabetes. The purpose of this study is to investigate the effect of presence of glucose and glycation of hemoglobin on absorbance of aqueous hemoglobin solutions with different glucose concentrations. Measurements were taken using spectrophotometer EQUINOX 55 (Bruker Optic GmbH) in a range 1000-1800 nm.Water has absorption bands in the near-infrared region which may be influenced by glucose presence. We have hypothesized that glucose and hemoglobin, especially glycated hemoglobin, may influence the absorption band of water in solution. The hemoglobin solutions with different amount of glucose (from 0 to 1000 mg/dl with a step 100 mg/dl) were incubated up to 28 days. Our measurements show that presence of glucose affects the spectra of aqueous hemoglobin solutions. The magnitude of absorbance depends on glucose concentration. At the beginning of incubation hemoglobin solution without glucose has the lowest absorbance magnitude, but after a rather long time of incubation (28 days) the absorbance of hemoglobin solutions with glucose become smaller compared to the absorbance of hemoglobin solution without glucose. This fact may be explained by assumption of hemoglobin glycation, when glucose molecules chemically bind to hemoglobin, and water binding to hemoglobin. In the case of water binding to hemoglobin molecules the amount of free water molecules in solution decreases, so the water aborbance is excepted to decrease.

The monoclinic and tetragonal phase compositions and distribution in air plasma sprayed (APS) yttria-partially stabilized zirconia (YPSZ) thermal barrier coatings were studied. The coatings were produced from powders with varying phase concentrations, chemical purity and powder production processes. Both the powder and coatings were characterized using X-ray diffraction (XRD) and Raman spectroscopy. The use of environmental scanning electron microscopy (ESEM) and X-ray energy dispersive analysis (EDS) added morphological and elemental information to the study. XRD and Raman spectroscopy were shown to be powerful combined tools and shows an overall decrease in the monoclinic phase within the coatings produced from the different powders. The distribution of both the monoclinic and the tetragonal phases could be highlighted both in the coatings and the individual powder particles. This indicated changes in monoclinic concentration in the less dense areas of some of the coatings and a varying distribution across particles in some of the powders. Raman mapping over small areas also showed how phase surface distribution, on the coatings surfaces, could be assessed.

We develop a Monte Carlo model for optical coherence signal simulation and providing accurate and high resolution information on the birefringence properties of the connective tissues. To understand the polarized sensitive optical coherence tomography imaging mechanism the Monte Carlo technique is generalized for simulation of polarized low-coherent backscattering of optical radiation scattered within the randomly inhomogeneous turbid medium like the connective tissues. The results of simulation demonstrate a good agreement both with the theoretical and experimental predictions.

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