Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 253-257). Available also in a digital version from Dissertation Abstracts.

No description available.

Thesis--Wisconsin. / Includes bibliographical references (leaves 38-39).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1981. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 521-531).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 90-92).

No description available.

This thesis describes the development of wide bandwidth ultrasonic pulse transmission and pulse echo comparison spectrometer methods to measure the ultrasonic phase velocity and absorption in natural rubber latex. Details of the quantitative design and construction of simple prototype test rigs include the mechanism of: variable path length pulse transmission, variable path length reflected pulse echo, and dual transducers reflected pulse echo. Special signal processing of experimental data, including transducer impulse response correction routines to calculate the acoustical parameters, are outlined. Measurements made using the constructed prototype test rigs are compared with each other and with data available in the pulished literature. A selection of methods to suit varying requirements for acoustical measurements in natural rubber latex samples is made. Calibration curves relating the measured ultrasonic absorption and phase velocity with the dry rubber content (d.r.c.) at temperatures of 20 to 30°C were constructed. Experiments to test the usefulness of these calibration curves were undertaken to determine if there was any deviation from the Standard Laboratory Method. A comparison between the experimental results obtained using the dual transducer reflected pulse method and the simulation of the Allegra and Hawley model with multiple scattering is presented. Good agreement was obtained between the experimental and the theoritical approaches up to 40% d.r.c. The feasibility of the detection of adulterant materials in natural rubber latex concentrates by using an ultrasonic method is discussed. Finally, the dual transducers reflected pulse echo technique is found be an alternative method to determine d.r.c. in natural rubber latex and could be used as a real time monitoring system for liquids and suspensions in a production environment.

This research work is devoted to the development of a finite element model for the simulation of the flow and mixing of rubber with carbon black in internal mixers. A set of continuity, motion, thermal energy, free surface, filler concentration and effective filler volume fraction equations are used in conjunction with the generalized Newtonian and the (CEF) constitutive equations to construct the present mathematical model. These equations are solved in two-dimensional Eulerian and Arbitrary Lagrangian-Eulerian (ALE) frameworks using continuous and discrete penalty methods and streamline-upwind Petrov-Galerkin techniques. Two different time stepping methods, namely, the Taylor-Galerkin and the implicit θ techniques are used and the effectiveness of these methods is compared. The developed algorithm is based on a de-coupled iterative scheme which can very effectively cope with the non-linear nature of the working equations. The developed model is initially used to simulate the free surface flow of silicon rubber in a flow domain which represents a purpose built flow visualization rig. The good comparison of the flow patterns generated by the present model and the experimentally recorded free surface regime in this rig confirms the general accuracy of the developed model. Following this verification the developed model is applied to simulate the flow and mixing of rubber with carbon black in partially filled tangential rotor internal mixers. These analyses yield velocity, pressure, temperature and concentration distributions inside the partially filled internal mixer domains. The close comparisons between the simulated pressure and temperature fields in the mixer domains with the available experimental data provide a strong indication for the general applicability of the developed model.

No description available.