An analytical tool is developed that is capable of predicting both present and future transportation policy impact on urban air quality. The Transportation Air Pollution Analysis Procedure (TAPIP) combines a versatile traffic assignment computer program model with an urban diffusion computer program model. TAPAP assesses the air quality impact of transportation policies such as extra lanes to an urban freeway, construction adding of new roadways, changes in auto emission standards, and exclusive bus lanes. With the stringent air quality standards now being legislated, TAPAP's ability to quantitatively measure a transportation system's present and future impact on air quality is indispensable to urban planning. The TAPAP program utilizes a modified version (APRAC-EM) of the original APRAC-1A urban diffusion computer program model. APBAC-EM, with its emission model, more effectively stimulates CO concentrations during peak-hour periods when CO concentration are most critical. / Master of Science

There are certain disadvantages to using round bars for plane strain fracture toughness testing. Specifically these are: (1) a large amount of material is required, for specimen fabrication, (2) a testing machine of great capacity is needed to fail such specimens, (3) there is considerable difficulty and expense involved in precracking the specimens. In attempt to Obtain a specimen free of these disadvantages, a hollow circumferentially notched round configuration has been suggested for plane strain fracture toughness testing. The effect of notch root radius and axial hole diameter were experimentally determined for hollow notched round aluminum bars of half inch outside diameter. From the results of the fracture toughness tests of these half inch specimens, it was concluded that a specimen of larger diameter was necessary in order to produce valid K_IC results. The equation used to calculate K_IC for hollow round bars was used to determine optimum dimensions for hollow round specimens. Several 7075-T651 aluminum. specimens of the analytically determined dimensions ' were failed and the corresponding apparent K_IC calculated. The resulting apparent K_IC values fell within an acceptable range of the true K_IC. It may be concluded that optimum dimensions may be analytically determined for hollow round plane strain fracture toughness specimens which will yield a reasonably accurate apparent K_IC. / Master of Science

The control problem of a large-order flexible system in the form of a beam-lattice is presented using the Independent Modal-Space Control (IMSC) method. The method is based on a transformation of the system equations of motion to modal space, yielding internally independent modal equations of motion. The control laws are designed in the modal space, permitting independent control of each mode, providing complete decoupling of the equations of motion. Linear optimal control with quadratic performance index is designed to control the response of the elastic as well as the rigid body modes, using the IMSC method. Actuators placement is of fundamental importance in the control of two-dimensional domains if IMSC is used. A method is presented as to the selection of actuators configuration in order to avoid singularity in the mode participation matrix, guaranteeing system controllability. The minimum-fuel problem is a very important one in the design of various space structures. Solution of the minimum-fuel problem is feasible in a coupled form for a fourth order system at most, but will be of insurmountable computational difficulty in the control of a flexible structure, since the model of such system will require a large number of degrees of freedom. A reformulation of the problem in the framework of "Modal Minimum-Fuel Problem" is presented, using the IMSC method. By this method, the complexity inherent in a high-order system is reduced, thus treatment of the coupled high-order system is avoided. Numerical examples for linear optimal control, with quadratic performance index, as well as for the minimum-fuel problem, are presented. / Ph. D.