This study utilized polycondensation reaction to synthesize fully conjugated rod-like polymer dihydroxy-PBI. Chemical derivatizations were applied to attach pendants of propane sulfonic coil for dihydroxy-PBI-PS and to attach aromatic phenylene ring with Li ionic moiety for dihydroxy-PBI-AS. The attachment of pendants for dihydroxy-PBI-PS was 42.27 % and for dihydroxy-PBI-AS was only for 0.04 % causing by stereo hindrance of this molecule. These polymers seemed to have good thermal stability. Dihydroxy-PBI started to show degradation at 467.8 oC and retained 60.5 wt. % at 800 oC. Derivatized dihydroxy- PBI-PS and dihydroxy-PBI-AS lost their pendants at 295.3 oC and 314.4 oC, respectively. Dihydroxy-PBI was cast into thin film. Upon doping with lithium salt of LiClO at 2.02 wt. %, dihydroxy-PBI cast film showed the highest room-temperature dc conductivity parallel to the film (£m¡ü) of 1.71 x 10-4 S/cm and perpendicular to the film (£m¡æ) of 1.49 x 10-5 S/cm. For dihydroxy-PBI-PS cast film, the highest conductivity was at 0.49 wt. % of LiClO4 with £m¡ü of 1.05 x 10-3 S/cm and £m¡æ of 1.05 x 10-4 S/cm. For dihydroxy-PBI-AS cast film, the highest conductivity was at 2.02 wt. % of LiClO4 with £m¡ü of 1.32 x 10-3 S/cm and £m¡æ of 2.26 x 10-5 S/cm. From scanning electron microscopy and wide-angle x-ray scattering, it was learned that cast films of dihydroxy-PBI and dihydroxy-PBI-AS had anisotropic layered structure parallel to the film, and that of dihydroxy-PBI-PS showed less of this anisotropy.

Reciprocating rod seals are widely used in hydraulic systems to prevent the hydraulic fluid from leaking into and polluting the environment. In this research an elastohydrodynamic model of a generalized reciprocating hydraulic rod seal, including mixed lubrication and surface roughness, has been successfully developed. This model consists of coupled fluid mechanics, contact mechanics, thermal analysis and deformation analyses. Such model is capable of predicting the key seal performance characteristics, especially net leakage and friction force. This allows evaluation of potential seal designs and serves as design tools. Also as this model has been developed, the basic physics of seal operation has been clarified, which stimulates the development of innovative seal concepts, such as seals with engineered sealing surfaces. The results of this study indicate that in general, hydraulic rod seals operate in the mixed lubrication regime, although under certain conditions full film lubrication may occur over a portion of the sealing zone. The roughness of the seal surface and the rod speeds play important roles in determining whether or not a seal will leak. Cavitation during the outstroke and partial full film lubrication during the instroke tend to prevent net leakage. The behavior of a reciprocating hydraulic rod seal with a double lip or two seals in tandem arrangement can be very different from that of a similar seal with a single lip. For the double lip seal, the secondary lip can strongly affect the behavior of the primary lip by producing an elevated pressure in the interlip region. The same seal characteristics that promote effective sealing in a single lip seal and, in addition structural decoupling of multiple lips, are found to promote effective sealing in a multiple lip seal. The model is validated through comparisons of model predictions with experimental measurements and observations by industry partners. The results have shown the predicted leakage and friction force for various seal and operation conditions are consistent with the measurements. A seal with micro-pattern on the sealing surface also has been investigated. The results indicate that an elaborately designed pattern can improve the sealing characteristics of the seal, without significantly affecting the friction force. In the end, the selection of the rod seal for a specific application using this analytical model is demonstrated. The best design can be picked up before a prototype being built.

We develop a general computational model for a elastic rod which allows for extension and shear. / Physics

The limit of current technology for mobile base station filters is the multimode filter, in which each cavity supports two (or possibly three) independent degenerate resonances. Shielded dielectric resonators with a rectangular cross-section are useful in this application. In the design of these filters, manufacturers are using software packages employing finite element or finite difference time domain techniques. However, for sufficient accuracy these procedures require large numbers of points or elements and can be very time consuming. Over the last decade research using the mode matching technique has been used to solve this kind of difficulty for various types of filter design and waveguide problems. In this thesis a mode matching method and computer program is developed to calculate the propagation coefficients and field patterns of the modes in a shielded rectangular dielectric rod waveguide. Propagating, complex, evanescent and backward wave modes are included and the work shows the presence of a dominant mode, and other fundamental modes, not previously identified. The effect of the shield proximity on the propagation characteristics and mode spectrum is investigated, together with the limitations on the accuracy of the mode matching method. In addition, the fields within the shielded rectangular dielectric rod waveguide, are used to calculate the attenuation coefficient of the dominant and fundamental modes. The influence on the attenuation coefficient of the proximity of the shield to the rod is also evaluated for these modes and limitations on accuracy are discussed. The calculated numerical results for the propagation and attenuation coefficient values are verified by measurement. The propagation coefficients results are typically within 2% of those measured. Verification of the attenuation coefficient results is achieved by comparing calculated and measured Q at the resonant frequencies of a number of shielded rectangular dielectric rod resonators. The difference between calculated and measured Q values is on average less than 4%. In the absence of a full solution of the shielded rectangular dielectric rod resonator, these results provide useful design information for this structure. In addition, the work reported in this thesis provides a basis for a full electromagnetic solution of this type of resonator. This would encompass the cubic dielectric resonator in a cubical cavity.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 107-117).

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This thesis is dedicated to the problems of gender assignment to English loan words in Italian. The thesis is divided into two parts. In the first, theoretical part, attention is paid to the definition of gender category in Italian, to the rules describing the formation of gender in Italian and then the gender assignment rules for English loan words are presented in detail. The second, analytical part, is dedicated to the research which is carried out via Italian text corpus itWaC. The application of the presented rules for gender assignment is being verified on a sample of English loan words.The aim of the thesis is to introduce the problems of gender assignment to English loan words in Italian, to provide a detailed overview of the individual rules for gender assignment and to verify how much are these rules observed in practice.

Magister Scientiae - MSc (Biotechnology) / The vaginal mucosa is dominated by Gram positive, rod shaped lactobacilli which serve as a natural barrier against infection. In both healthy and BV infected women Lactobacillus crispatus and Lactobacillus jensennii has been found to be the predominant Lactobacillus species. Many studies have been conducted to assess factors influencing lactobacilli dominance in the vaginal microbiome. However, no study has evaluated the impact of plasmids on the vaginal lactobacilli. In the present study two plasmids, pLc17 and pLc4, isolated from vaginal Lactobacillus species of both healthy and BV infected women were characterized. pLc4 was present in both Lactobacillus crispatus and Lactobacillus jensennii while pLc17 was only present in Lactobacillus crispatus. pLc17 (16663 bp in size) encoded a ribonucleotide diphosphate reductase (RNR), a filamentation induced by cAMP-like (FIC-like) protein and numerous mobile elements.

Over the last few decades there has been a confusion in the classification system of organisms with the development of molecular and genetic methods. Life is currently perceived from a different perspective than in the past due to different methods, and old, standard systems have significantly changed as a result of such alteration. As a consequence, it is harder and harder to distinguish which taxonomic changes are caused by objectively better recognition of biodiversity and which seem to be only subjective opinions of particular taxonomists. Results show a significant growth in the number of genuses in observed families of frogs (Anura) in the aforementioned period (2000-2017) while the research efforts of taxonoms were proved to be the most relevant factors causing such increase in diversity with respect to genuses.

In a nuclear fuel cask, the heat generating spent fuel rods are packed in a housing and the resulting bundle is placed inside a cask of thick outer shell made of materials like lead or concrete. The cask presents a wide variation in geometrical dimensions ranging from the diameter of the rods to the diameter of the cask. To make the problem tractable, first the heat generating rod bundle alone is considered for analysis and the effective thermal conductance of the bundle is correlated in terms of the relevant parameters. In the second part, the bundle is represented as a solid of equivalent thermal conductance and the attention is focused on the modelling of the cask. The first part, dealing with the effective thermal conductance is solved using Fluent software, considering coupled conduction, natural convection and surface radiation in the heat generating rod bundle encased in a hexagonal sheath. Helium, argon, air and nitrogen are considered as working media inside the bundle. A correlation is obtained for the critical Rayleigh number which signifies the onset of natural convection. A correlation is also developed for the effective thermal conductance of the bundle, considering all the modes of transport, in terms of the maximum temperature in the rod bundle, pitch-to-diameter ratio, bundle dimension (or number of rods), heat generation rate and the sheath temperature. The correlation covers pitch-to-diameter ratios in the range 1.1-2, number of rods ranging from 19 to 217 and the heat generation rates encountered in practical applications. The second part deals with the heat transfer modeling of the cask with the bundle represented as a solid of effective (or equivalent) thermal conductance. The mathematical model describes two-dimensional conjugate natural convection and its interaction with surface radiation in the cask. Both Boussinesq and non-Boussinesq formulations have been considered for convection. Numerical solutions are obtained on a staggered mesh with a pressure correction method using a custom-made Fortran code. The surface radiation is coupled to the conduction and convection at the solid-fluid interfaces. Steady-state results are obtained using time-marching. Results for various quantities of interest, namely, the flow and temperature distributions, Nusselt numbers, and interface temperatures, are presented. The Grashof number based on the volumetric heat generation and gap width is varied from 105 to 5 ×109. The emissivities of the interfaces are varied from 0.2-0.8 for the radiative calculations. The solid-to-fluid thermal conductivity ratio for the inner cylinder is varied in the range 5-20 in the parametric studies. Simulations are also performed with thermal conductivity calculated in an iterative manner from bundle parameters. The dimensionless outer wall conductivity ratio is chosen to correspond to cask walls made of lead or concrete. The dimensionless thickness (with respect to gap width) of the outer shell is in the range of 0.0825-1, while the inner cylinder dimensionless radius is 0.2. Air is the working medium in the cask for which the Prandtl number is 0.71. Correlations are obtained for the average temperatures and Nusselt numbers at the inner interface in terms of the parameters. The radiation heat transfer is found to contribute significantly to the heat dissipation.