No description available.

We have designed and fabricated a biomicroviscometer platform for measurement of microflows of biological fluids. The biomicroviscometer combines an optically clear biocompatible polydimethylsiloxane (PDMS) channel with on-chip integrated microfluidic differential pressure sensors and capabilities of modular channel geometries. This setup allows for a direct measurement of the change in pressure and flow rate, increasing the overall accuracy of the measurement of viscosity and optical observation. We present an introduction of this combined method of measurement with different channel dimensions, using Newtonian and non Newtonian fluids, and the corresponding calculations. This measurement technique has potential applications in measuring rheological properties at the micro level to further blood disease analysis, and lab-on-a-chip fabrication and analysis.

No description available.

Helix-sense-selective polymerization of poly(3-methyl-4vinylpyridine) have been carried out using the DPEDAHLi

Thesis (Doctor)--Technische Universiteit Delft, 2006. / Includes bibliography (p. 134-136).

Among the many and varied fields of present day chemistry, that of optical activity occupies a not unimportant position. The rotatory powers of the alkali and ammonium salts of d-sec-βoctyl hydrogen phthalate have been studied in alcoholic and aqueous solution. The rotations of the salts were found to be in the order H > Li > NH4 > Na > K > Rb. It has been concluded that the variation of the molecular rotation of the salts with concentration may be explained by assuming changes in the degree of dissociation of the electrolytes and a deforming influence of the cations on the optically active anions. The effect of the addition of inorganic salts of various valence types to 0.2 M aqueous solutions of d-sec-β-octyl sodium phthalate has been investigated. The series for the depressive influence of the alkali and ammonium chlorides on the rotatory power of the optically active electrolyte is Cs+> Rb+> K+> Na+> NH4+> Li+. The corresponding series for the divalent chlorides is Ba++> Sr++> Ca++> Mg++. It is concluded that the observed effects may be attributed mainly to a deforming influence of the positive ion on the optically active negative ion, the explanation involving a consideration of the ionic radii. It is worthy of comment that the above results have been obtained by use of a carboxylic acid containing no hydroxyl group.

Detection and inspection of metal surface corrosion in the ballast tanks of U.S. Navy ships has been a long time problem. The adverse climatic conditions to which the ballast tanks are exposed and the uneven geometry of ballast tanks makes the visual inspection process of surface coatings a difficult job. Thousands of tanks are inspected yearly, with the average cost of an individual tank inspection at approximately $8-15 thousand/each. To aid the visual inspection process, this research is conducted to develop a new technique to automate the visual task of metal surface inspection by image acquisition and post processing. The best results of image processing are achieved by the enhanced contrast between the paint defect and the background using a newly developed optically active additive (OAA) used in paints. Thorough investigation of image processing algorithms has been carried out and a background of imaging theory and experiments is illustrated in this work.

published_or_final_version / abstract / Earth Sciences / Doctoral / Doctor of Philosophy

The material that is covered in this thesis concerns the calibration and application of a set of optical tweezers to be used for one- and two-point micro-rheology experiments on hard sphere colloidal suspensions. The colloidal suspensions that were used in this study were all quasi-monodisperse density- and refractive index-matched PMMA particles that had a radii, a = 0:90 ± 0:05μm or a = 0:86 ± 0:07 for one-point microrheology experiments and radii a = 0:90 ± 0:05μm or a = 0:133 ± 0:010μm for the two-point micro-rheology experiments. By collecting the forward scattered light from a single optically trapped particle the particle's displacements in time were used to determine passive microviscosity, η(Passive) μ , for colloidal suspension in the range of 0:10 < Ø < 0:57 and comparison with literature data has been made and agreement found. Actively dragging an optically trapped particle through suspensions with volume fractions of the same range has yielded the active microviscosities, η(Active) μ , for both high and low shear regimes, displaying shear thinning behaviour. Comparison to literature data has been made and agreement found as well. Collecting the forward scattered light from two optically trapped particles has been used to determine the cross-correlated motion of the two particles in bare solvent and in suspensions with volume fraction Ø = 0:02. The friction coefficients ξ1;1 and ξ1;2 were extracted from the cross-correlated motion of the particles and agreement was found with theoretical predictions for bare solvent only. The suspensions with volume fraction Ø = 0:02 were found to have a friction coefficient ξ1;1 that was greater than what theory predicted with the suspension with bath particles a = 0:90 ± 0:05μm had the greater magnitude. The magnitude ξ1;2 was found to decrease for the suspension with bath particles of radius a = 0:133 ± 0:010μm and to increase for the suspension with bath particles a = 0:90 ± 0:05μm.

Two-port polarization independent electro-optically wavelength tunable filters based on asymmetric Mach-Zehnder structure in LiNbO3 substrate have been developed for 1.55μm application. The operation principle is based on Mach-Zehnder interference and TE↔TM mode conversion. Fabrication parameters for channel waveguides, interferometers and mode converters have been optimized. 7μm wide single mode straight channel waveguides were produced by diffusing 1050-1100A thick Ti into LiNbO3 substrate. Insertion loss of 3.6dB was achieved for both TE and TM polarization. Mach-Zehnder interferometer performance was optimized by testing the Y-branch on samples cut in half length compared to complete device. Best results were obtained from samples that were produced by diffusion at 1025 degC for 11 hours of 1050A thick Ti film, and by diffusion at 1025 degC for 12 hours of 1090A thick Ti film. Metal electrodes were added to one arm of asymmetric Mach-Zehnder interferometers to evaluate electro-optic modulation. Modulation depth as high as 99.6% for TE mode and 98.9% for TM mode were obtained. TE↔TM mode conversion was demonstrated on straight channel waveguides with conversion efficiency greater than 96% utilizing 500 strain inducing SiO2 grating pads with 21μm spatial period. Two-port polarization independent electro-optically tunable wavelength filters were produced based on the optimized parameters described above. The -3dB bandwidth of the filter is 2.4nm. The nearest side lobe to the main peak is more than 13dB below the central lobe for both TE polarization and TM polarization. A thermal tuning rate of -0.765nm/degC is obtained. An electrical tuning range of 12.8nm and a tuning rate of 0.08nm/V were achieved.