Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Dr. John G. Dorsey, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Sept. 19, 2005). Document formatted into pages; contains xxii, 154 pages. Includes bibliographical references.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references. Also available in electronic version.

Two new apparati have been developed to measure solid-liquid and liquid-liquid equilibria via a synthetic visual method by determination of thermal signatures. One apparatus adopts a technique of using Peltier modules for cooling, and the other is a well-known design that uses a cryogenic fluid in a thermostatted glass cell for cooling of the sample. The Peltier design is for small sample volumes, with a 10 cm3 aluminium equilibrium cell and has a minimum operating temperature of 253.15 K. The glass design is developed to complement the Peltier and has a larger volume of 140 cm3 and a minimum operating temperature of 223.15 K. Both apparati have been semi-automated in order to increase the accuracy and improve the efficiency of data measurements. Therefore the experimenter no longer has to wait for many hours for the determination of equilibrium. This was done by incorporating software, which was specially designed for the apparati using Labview8TM, for controlling the cooling and heating rates. The uncertainty of the temperature measurements was found to be ±0.03 K for the Peltier apparatus and ±0.02 K for the Glass apparatus. Liquid-liquid equilibria data has also been measured on the Peltier apparatus, to demonstrate its versatility. This was done using a digital camera, controlled through the Labview software to identify cloud points. The results have been found to be comparable with literature values. For solid-liquid equilibria new systems of n-alkyl carboxylic acid binary mixtures have also been measured: heptanoic acid + butyric acid and heptanoic acid + hexanoic acid. These systems were measured using both apparati and both systems exhibited eutectic behaviour. All eutectic temperatures were measured on the Glass apparatus. Experimental data for these systems was modelled using the local composition models: Wilson, NRTL and UNIQUAC models. The NRTL model was found to give the best results for both systems with root mean square deviations (RMSD) of 2.16 K and 1.27 K and absolute average deviations (AAD) of 0.61 K and 0.49 K, between temperature measurements of this work and those calculated from the models, for the heptanoic acid + butyric acid and heptanoic acid + hexanoic acid systems, respectively. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.

The scarcity of research about nitrogen containing heterocyclic discotic liquid crystal has made it an interesting subject for chemists. In this thesis, we will discuss the synthesis and properties of four kinds of new dimeric discotic liquid crystal in details. The first type of new dimeric discotic liquid crystals were synthesized based on a novel core structure, dibenzo[a,c]phenazine. All dimers linked by a hexyl-chain spacer exhibited columar phase. The range of mesomorphic temperature became wide as the chain length of spacer increased. Simultaneously, we also changed terminal chain length to investigate the influence on mesomorphic properties by attached terminal group. The second type of new dimeric discotic liquid crystals, which contained the dibenzoquinoxaline skeleton, didn¡¦t show the properties of mesomorphic phase due to the poverty of planality. The third type of molecules, which also have the dibenzoquinoxaline skeleton, were the banana-shaped discotic liquid crystals. We anticipated these dimeric molecules would demonstrate another special mesogenic phase. The last type of dimeric discotic liquid crystals were the extension of our previously research. These molecules, which comprised 5,6,11,12,17,18- hexaazatrinaphthylene skeleton, would be good candidates for using as a n-type material.

Thesis (Ph.D.)--Kent State University, 2005. / Title from PDF t.p. (viewed Sept. 14, 2006). Advisor: Philip J. Bos. Keywords: liquid crystal; diffractive optical element; optical phased array; spatial light modulator; high resolution wavefront control; aberration correction. Includes bibliographical references (p. 206-213).

Thesis (Ph.D.)--Kent State University, 2004. / Title from PDF t.p. (Aug. 16, 2006). Advisor: Liang-Chy Chien. Includes bibliographical references (p. 133- 137).

No description available.

One-, two- and three-phase mixing systems have been extensively studied. The experiments were performed in a range of standard (baffled) vessel geometries of diameter varying between 0.22 - 1.83 m. Rushton disc turbines and mixed flow impellers (both pumping directions) were fully investigated. Water and glucose solution (~ - 120 mPas) were employed. For single phase systems, the work has shown that the power number of disc turbines depends on disc thickness and scale of vessel. For the mixed flow agitators the power number is dependent upon the blade thickness and (D/T) ratio. Correlations enabling the ungassed power number to be calculated as a function of these parameters are given. For gassed systems, the power drawn by each type of impeller is explained by local impeller hyarodynamics (cavity structure) and the bulk flow pattern. The fiooding-Ioading transition (NF) and the complet~ dispersion condition (NeD) have also been studied. A large mixed flow impeller (6MFU45 ; D - T/2) with a large ring sparger is the most energy efficient at NF and NCD speeds as compared with the other geometries studied and correlations enabling the prediction of NF and NCD for all geometries studied are presented. Hold-up correlations are also given for each impeller firstly as a function of specific energy dissipation rate and superficial gas velocity and secondly as' a function of agitator speed and volumetric gassing rate. For each impeller, each method is equally good statistically for scale-up but the latter is more explicit. All impellers give approximately the same hold-up under equal specific power inputs and superficial gas velocity but there are small but statistically significant differences. These differences are discussed. For solid-liquid systems, correlations in the literature for the calculation of the minimum speed to just suspend solids, NJS ' are tested for each system geometry with glass Ballotini particles. The correlation proposed by Chapman et al. is shown to fit the present experimental data best. The specific power input per unit mass (ET)JS - constant, is proposed as a scale-up criterion for solids suspension. Large 6MFD45 (D - T/2) is the most energy efficient for suspension but 6MFU45 (D - T/2) is only slightly worse. In the three-phase mixing systems, the 6MFD 45 , D - T/2, is most energy efficient for solid suspension (ET)JSg' at low gassing rates (up to 1 vvm) but exhibits large flow pattern and torque fluctuations. Above _ 1 vvm, 6MFU45 (D = T/2) becomes the most energy efficient for solid suspension. In addition the minimum impeller speed for solid suspension NJSg for this impeller is almost independent of gassing rate and gives very stable flow patterns and torque. output throughout the whole gassing range. Again (eT)JSg - const is the recommended scale-up criterion for solids suspension under gassed conditions. Large (D - T/2) impellers are found to be more energy efficient and correlations for predicting N 45 45 . JSg for 6DT. 6MFD and 6MFU are obta~ned. Increase in liquid viscosity has a rather small effect on gas dispersion. Up to 120 mPas: (N) Q:I (N ) and (N ) Q:I F viscous F water CD viscous (NCD) water uO.06 On the other hand, viscosity has a significant effect on NJS and 3 to 5 times more energy is required for solid suspension at 120 ,mPas.

No description available.

Interfacially active reagents are utilized in metal solvent extraction processes and it is therefore important to understand the role of the liquid-liquid interface in the study of the kinetics and equilibria of extraction. The diffusion problems encountered in the traditional apparatus were overcome by using a high speed stirring apparatus. The microporous teflon membrane phase separator permitted more accurate measurements of interfacial areas, characterization of extraction kinetics of metal chelates, and a greater understanding of the phase separation mechanism. In contrast to the neutral ligands, the anionic ligand of dithizones and substituted dithizones showed significant interfacial adsorption at the chloroform/water interface as monitored spectro-photometrically. Equilibrium studies on p-halodithizones indicated that the adsorption constant increased as the substituent was altered from chloro to bromo to iodo, and with the distribution ratio of the ligand. Kinetic studies on dithizone and p-iododithizone with Ni(II) and Zn(II) indicated that the extent of participation of the interface in solvent extraction kinetics of these metal ions is dictated by the interfacial activity of the extractant and the mechanisms of the rate limiting step in the bulk aqueous and interfacial regions.