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The couple stress theory as presented by Mindlin, Koiter, Stokes and others is reviewed with particular attention being given to stress concentration and size effects. That theory is compared on a qualitative and quantitative basis with Neuber's theory for stress concentration for very small or sharp notches and with observed notch sensitivity effects in aluminum and steel. It is established that, in order to explain observed elastic size effects in these materials, the new material constant ℓ which is characteristic of the couple stress theory must be on the order of magnitude of .02". In order to determine order of magnitude of the constant, a series of experiments was designed based on a thin plate analysis developed here. The plate theory uses the basic assumptions of classical plate theory as well as several, as explained in the text, necessary when couple stress is included. The formulation resulted in a set of equations for plate deflection including classical and couple stress terms in such a way that when the constant ℓ was allowed to be zero, the classical equations resulted. Experimentally, it was found that the couple stress effect in steel and aluminum is at least one order of magnitude too small to account for observed size effects as was suggested by Mindlin. In addition, the magnitude of ℓ was found to be such that its effect would undoubtedly be clouded by inhomogeneity and anisotropy of metals at the microstructural level. The results represent the only known experimental data at the time of publication dealing with couple stress in metals and would seem to be the next obvious step in the development of the theory which has proceeded on a purely mathematical plane. An alternate approach to account for the effects of microstructure in notch sensitivity is discussed. / Ph. D.

The purpose of this study is to review employee unionism and employee-management relations as they exist in the Federal public service of the United States. Attention is given to the historical development of employee organizations with the record of the Government as an employer as a background. The work of the Kennedy Task Force on Employee-Management Relations in the Federal Service is reviewed together with progress in employee-management relations since Executive Order 10988 was issued implementing the Task Force's recommendations. Employee-management relations in the central governments of Great Britain, Australia, and Canada are discussed to provide a comparative framework within which the United States' experience may be viewed and considered. / M.S.

This thesis investigates the design of a strip tension regulator by analytical techniques. The tension transfer function is non-linear and is derived for two conditions, first with only elastic deformation in the strip, and second with plastic flow in the strip resulting from reduction in the roll bite. The resulting transfer function consists of the one developed for elastic deformation with a degenerative feedback around it. This feedback is a result of reduction in the roll gap. The block diagram of the tension system reduces to a form containing two non-linear expressions. One is a second order equation describing the load and the other is third order equation describing the motor and the load effect on it. The motor is linearized by the addition of a high response armature current regulator. The tension regulator then reduces to a type I third order system. To compensate for the second order non-linearity in the regulator, a non-linear second order lead circuit is developed. This lead is modified continually as a function of strip velocity as well as coil radius and inertia. With the addition of this compensation, the tension regulator can be analyzed as a type I, first order system. / M.S.