I Wandered Lonely as a Spy: Advanced Study and Elementary Research

Distinguished Lecture of the Institute and Society for Advanced Study given on October 9, 1998

Integrated Planning for Telepresence With Time Delays

A conceptual "intelligent assistant" and an artificial-intelligence computer program that implements the intelligent assistant have been developed to improve control exerted by a human supervisor over a robot that is so distant that communication between the human and the robot involves significant signal-propagation delays. The goal of the effort is not only to help the human supervisor monitor and control the state of the robot, but also to improve the efficiency of the robot by allowing the supervisor to "work ahead". The intelligent assistant is an integrated combination of an artificial-intelligence planner and a monitor of states of both the human supervisor and the remote robot. The novelty of the system lies in the way it uses the planner to reason about the states at both ends of the time delay. The purpose served by the assistant is to provide advice to the human supervisor about current and future activities, derived from a sequence of high-level goals to be achieved

Nonequilibrium Stagnation-Line Radiative Heating for Fire II

This paper presents a detailed analysis of the shock-layer radiative heating to the Fire II vehicle using a new air radiation model and a viscous shock-layer flowfield model. This new air radiation model contains the most up-to-date properties for modeling the atomic-line, atomic photoionization, molecular band, and non-Boltzmann processes. The applied viscous shock-layer flowfield analysis contains the same thermophysical properties and nonequilibrium models as the LAURA Navier-Stokes code. Radiation-flowfield coupling, or radiation cooling, is accounted for in detail in this study. It is shown to reduce the radiative heating by about 30% for the peak radiative heating points, while reducing the convective heating only slightly. A detailed review of past Fire II radiative heating studies is presented. It is observed that the scatter in the radiation predicted by these past studies is mostly a result of the different flowfield chemistry models and the treatment of the electronic state populations. The present predictions provide, on average throughout the trajectory, a better comparison with Fire II flight data than any previous study. The magnitude of the vacuum ultraviolet (VUV) contribution to the radiative flux is estimated from the calorimeter measurements. This is achieved using the radiometer measurements and the predicted convective heating. The VUV radiation predicted by the present model agrees well with the VUV contribution inferred from the Fire II calorimeter measurement, although only when radiation-flowfield coupling is accounted for. This agreement provides evidence that the present model accurately models the VUV radiation, which is shown to contribute significantly to the Fire II radiative heating

State Defiance of Bankruptcy Law

Bankruptcy is the principal device by which failing businesses and financially-troubled families get one last chance to reorganize their affairs back to financial health. It is also the graveyard for business failures, the place where we bury dead corporations and divide their remaining assets among their surviving creditors. In the last decade, the bankruptcy system has given seven million middle-class families a way to start over-an opportunity to save their homes from foreclosure, rid themselves of overwhelming debts, and reintegrate themselves into the workforce as productive citizens. It has also been the way that 10,000 corporations have restructured their way from failure to health, avoiding the disruptive costs of dissolution and liquidation and instead preserving jobs, stabilizing community tax bases, and fueling the longest period of economic expansion in United States history. Another 100,000 less fortunate corporations have had their funerals in bankruptcy, as their creditors have divided their assets and facilitated the redistribution of capital and labor resources that must accompany liquidation. Bankruptcy is the safety valve in America\u27s capitalist system: technical and arcane, but so important. For the last 100 years, bankruptcy has functioned efficiently, providing a vital lubricant at the rough edges of the American economy. We do not expect individuals to live life without hope and force them into the underground economy to avoid a mountain of debt. Nor do we discourage entrepreneurs from starting new ventures by holding them personally liable if that corporate venture fails. Instead, we give each individual and business person a fair chance to start over. This second chance breeds innovation and risk taking that puts the United States at the cutting edge of technological and scientific development. When our corporations experience liquidity problems, we do not allow lenders to shut them down and break them up. Rather, we permit sick businesses to file under chapter 11 to provide a breathing spell to rehabilitate themselves; if rehabilitation cannot be accomplished, we provide a forum for liquidation of the businesses for the collective good of all creditors

Development of Composite Sandwich Bonded Longitudinal Joints for Space Launch Vehicle Structures

The NASA Composite Technology for Exploration (CTE) Project is developing and demonstrating critical composite technologies with a focus on composite bonded joints; incorporating materials, design/analysis, manufacturing, and tests that utilize NASAs expertise and capabilities. The project has goals of advancing composite technologies and providing lightweight structures to support future NASA exploration missions. In particular, the CTE project will demonstrate weight-saving, performance-enhancing composite bonded joint technology for Space Launch System (SLS)-scale composite hardware. Advancements from the CTE project may be incorporated as future block upgrades for SLS structural components. This paper discusses the details of the development of a composite sandwich bonded longitudinal joint for a generic space launch vehicle structure called the CTE Point Design. The paper includes details of the design, analysis, materials, manufacturing, and testing of sub-element joint test articles to test the capability of the joint design. The test results show that the composite longitudinal bonded joint design significantly exceeds the design loads with a 2.0 factor of safety. Analysis pre-test failure predictions for all sub-element bonded joint test coupons were all within 10% of the average test coupon failure load. This testing and analysis provides confidence in the potential use of composite bonded joints for future launch vehicle structures

Viscosity Coefficient Measurement and Theoretical Interpretation for Hydrocarbon Mixtures

Accurate measurements of viscosity coefficients have been made for liquid hydrocarbon mixtures over a wide range of temperature and pressure. At saturation pressure, specially designed viscometers were used to measure the viscosity coefficient of binary, ternary and quaternary n-alkane mixtures, of binary mixtures of five n-alkane plus benzene systems and of benzene plus cyclohexane from 283 K to 393 K, with an estimated accuracy of +/- 0.5 percent. At elevated pressures, a falling-body viscometer with self-centring sinker was used to measure the viscosity coefficient of n-hexane, n-hexadecane and four binary mixtures with an estimated accuracy of +/- 3 percent from 298 K to 373 K at pressures up to 500 MPa or the freezing pressure. To overcome certain weaknesses in design of this instrument, a new viscometer was designed, built and tested. The accuracy of density measurement under elevated pressure was also significantly improved