Future of V/STOL aircraft systems: A survey of opinions

The recent success of the British Harriers in the Falkland Islands conflict vividly underscored the potential of V/STOL aircraft in military operations in a difficult environment. Despite this apparent success of the Harrier, there has been a major decline of V/STOL funding in the research and development budgets of the U.S. government and industry. The recent funding history of V/STOL systems is examined. Responses to a questionnaire which asked the question, Should there be an operational V/STOL aircraft other than the AV-8A and AV-8B in the military aircraft fleet of the U.S.A.? are presented and discussed

Fourier coding of images

Fourier transform coding and transmission of two dimensional images from far ranging space probe

What Makes Educational Campaings Succeed?

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The Function of Social Behavior in Water Resource Development

Preface: This report is an analysis of a social survey of the middle and lower Bear River Basin of southeastern Idaho and northern Utah concerning the problem of water resource development in a semiarid region of the Western United States. The survey part of the study, carried out in the summer of 1966, dealt with both general social factors and a specific proposal made by the Bureau of Reclamation for developing water resources of the Bear River. In many respects this proposal and the resulting behavior is typical of other western river basin projects, in some other ways, however, it is also unique. It is expected that the broad exploratory nature of this study will provide a useful background for other studies with more specialized and limited goals. The limited application of research to the behavioral problems of water resources research has guided the wide focus of this problem. This monograph reports a considerable amount of data. It is recommended that the reader interested in less detail might well confine himself to the champter summaries and the final chapter on conclusions. In some cases, in concluding or projecting, the writers have taken the liberty to speculate beyond the strict confines of the data, including some prespectives they have obtained in the process of the study. These occasions are indicated for the reader

Laser-modified one- and two-photon absorption:Expanding the scope of optical nonlinearity

It is shown that conventional one-photon and two-photon absorption processes can be made subject to nonlinear optical control, in each case significantly modifying the efficiency of absorption, through the effect of a secondary, off-resonant stimulus laser beam. The mechanistic origin of these laser-modified absorption processes, in which the stimulus beam emerges unchanged, is traced to higher-order terms in standard perturbation treatments. These normally insignificant terms become unusually prominent when the secondary optical stimulus is moderately intense. Employing a quantum formulation, the effects of the stimulus beam on one-photon and two-photon absorption are analyzed, and calculations are performed to determine the degree of absorption enhancement, and the form of spectral manifestation, under various laser intensities. The implications of differences in selection rules are also considered and exemplified, leading to the identification of dark states that can be populated as a result of laser-modified absorption. Attention is also drawn to the possibility of quantum nondemolition measurements, based on such a form of optical nonlinearity

Expansion of pinched hypersurfaces of the Euclidean and hyperbolic space by high powers of curvature

We prove convergence results for expanding curvature flows in the Euclidean and hyperbolic space. The flow speeds have the form $F^{-p}$, where $p>1$ and $F$ is a positive, strictly monotone and 1-homogeneous curvature function. In particular this class includes the mean curvature $F=H$. We prove that a certain initial pinching condition is preserved and the properly rescaled hypersurfaces converge smoothly to the unit sphere. We show that an example due to Andrews-McCoy-Zheng can be used to construct strictly convex initial hypersurfaces, for which the inverse mean curvature flow to the power $p>1$ loses convexity, justifying the necessity to impose a certain pinching condition on the initial hypersurface.Comment: 18 pages. We included an example for the loss of convexity and pinching. In the third version we dropped the concavity assumption on F. Comments are welcom