1,382 research outputs found

    The Law of Burial Insurance

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    Burial insurance, used in the sense of a risk-shifting device to aid the less fortunate, has existed in the form of friendly societies from time immemorial. Indeed, it is probable that this noncommercial type was the first form of insurance. There is some evidence that such societies existed in Egypt, 2500 B.C. There exists more concrete evidence that they thrived in ancient China, India, Greece and Rome. The Grecian societies, although largely religious and ritualistic, had as their main function the guarantee of a decent burial for their members. The existence around A.D. 117-138 of Roman societies, called collegia, is established beyond doubt by the finding of a marble bearing an inscription setting forth the by-laws., Although there is no documentary proof, it is probable that the societies survived the invasions and continued to exist in their ancient form until they were revived by the medieval guilds with many attributes of our modern mutual benefit organizations

    MEDATA - A new concept in medical records management

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    Computer program for medical records managemen

    A hydrogen energy carrier. Volume 2: Systems analysis

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    A systems analysis of hydrogen as an energy carrier in the United States indicated that it is feasible to use hydrogen in all energy use areas, except some types of transportation. These use areas are industrial, residential and commercial, and electric power generation. Saturation concept and conservation concept forecasts of future total energy demands were made. Projected costs of producing hydrogen from coal or from nuclear heat combined with thermochemical decomposition of water are in the range 1.00to1.00 to 1.50 per million Btu of hydrogen produced. Other methods are estimated to be more costly. The use of hydrogen as a fuel will require the development of large-scale transmission and storage systems. A pipeline system similar to the existing natural gas pipeline system appears practical, if design factors are included to avoid hydrogen environment embrittlement of pipeline metals. Conclusions from the examination of the safety, legal, environmental, economic, political and societal aspects of hydrogen fuel are that a hydrogen energy carrier system would be compatible with American values and the existing energy system

    A hydrogen energy carrier. Volume 1: Summary

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    The production, technology, transportation, and implementation of hydrogen into the energy system are discussed along with the fossil fuel cycle, hydrogen fuel cycle, and the demands for energy. The cost of hydrogen production by coal gasification; electrolysis by nuclear energy, and solar energy are presented. The legal aspects of a hydrogen economy are also discussed

    Investigation of Mobility Limiting Mechanisms in Undoped Si/SiGe Heterostructures

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    We perform detailed magnetotransport studies on two-dimensional electron gases (2DEGs) formed in undoped Si/SiGe heterostructures in order to identify the electron mobility limiting mechanisms in this increasingly important materials system. By analyzing data from 26 wafers with different heterostructure growth profiles we observe a strong correlation between the background oxygen concentration in the Si quantum well and the maximum mobility. The highest quality wafer supports a 2DEG with a mobility of 160,000 cm^2/Vs at a density 2.17 x 10^11/cm^2 and exhibits a metal-to-insulator transition at a critical density 0.46 x 10^11/cm^2. We extract a valley splitting of approximately 150 microeV at a magnetic field of 1.8 T. These results provide evidence that undoped Si/SiGe heterostructures are suitable for the fabrication of few-electron quantum dots.Comment: Related papers at http://pettagroup.princeton.ed

    Architectures and Algorithms for Distributed Generation Control of Microgrids

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    Microgrids and the control challenges they pose have recently received significant attention in a wide array of research communities. While the potential to increase efficiency, reliability, and adaptability of the utility grid is a primary motivation for their development, microgrids can also be used to meet the growing electric power demands in numerous applications. Compared with large power systems, microgrids may rely on inertia-less generators such as photovoltaic arrays that are interfaced through an inverter. Although the lack of inertia and other microgrid characteristics pose control challenges, microgrids are amenable to new control paradigms, e.g., those that rely on distributed computations rather than a centralized processor. We address the problem of distributed generation control in islanded ac microgrids with and without inertia. In the case of microgrids comprising heterogeneous generators, some of which have inertia, we propose a control architecture for frequency regulation and optimal dispatch designed to take advantage of microgrid-specific properties. For microgrids with no inertia, we propose a control architecture that is designed to drive the average frequency error to zero while ensuring that the frequency at every bus is equal and that the operating point that results is stable. In both cases, we also propose an implementation of each control architecture that relies on distributed algorithms that eliminate the need for a centralized processor with global information. For the architecture we propose for microgrids with inertia, we provide analytical and experimental results that verify the effectiveness of the proposed architecture, and illustrate the performance of the distributed algorithms on which it relies under a variety of scenarios. We verify the proposed control architecture for inertia-less microgrids by analytically showing that the resulting closed-loop system is stable; we also illustrate the features of the architecture using numerical simulations of three test cases applied to six- and 37-bus networks

    Adaptation to a Motion-Based and Non-Motion-Based Simulator

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    This study (N=129, including 59 males and 61 females) examined the issue of realism and motion sickness between motion-based and non-motionbased simulators. Specifically, this research address whether enhancing a driving simulator with motion capabilities increases the realism of the simulator and, if so, does this increase in subjective realism increase participants’ vulnerability to motion sickness. Approximately half of the participants drove a motion-based simulator while the other half drove a non-motion-based simulator on four independent drives within an experimental session. Results showed that the motion-based simulator was rated more realistic than the non-motion-based simulator. However, it was also found that participants in the motion-based simulator had higher negative physical health ratings than participants in the nonmotion-based simulator. Our results suggest that training programs need to consider the trade-off between realism and motion sickness

    Background light measurements at the DUMAND site

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    Ambient light intensities at the DUMAND site, west of the island of Hawaii were measured around the one photoelectron level. Throughout the water column between 1,500m and 4,700m, a substantial amount of stimulateable bioluminescence is observed with a ship suspended detector. But non-stimulated bioluminescence level is comparable, or less than, K sup 40 background, when measured with a bottom tethered detector typical of a DUMAND optical module

    Preparatory Piano Students Recital

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    This is the program for the preparatory piano students. Many students performed, including Sara Scott, Guy T. Nelson, Jr., Louis Byron Cady, Esther Garrett, Bruce Watson, Carol Drummond, Cynthia Landers, Mary Gail Baber, Denise Watson, David Dahlstedt, Veda Smith, Charlotte Goodson, Roy Cagle, Margery Goodson, Nancy Goodson, Danny Taft, Carol Cantrell, and Jim McCarty. This recital took place on May 23, 1963, in Mitchell Hall
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