5,870 research outputs found

    Caging Mechanism for a drag-free satellite position sensor

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    A disturbance compensation system for satellites based on the drag-free concept was mechanized and flown, using a spherical proof mass and a cam-guided caging mechanism. The caging mechanism controls the location of the proof mass for testing and constrains it during launch. Design requirements, design details, and hardware are described

    Daily Life in McMinnville 100 Years Ago

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    The McMinnville 100 Years Ago project is a collaborative research project that has been initiated by Professor Huntsberger’s History of Mass Communication class. This particular project topic focuses on the daily life of Yamhill County in 1912. As a group we have chosen to divide our project into different subject areas: churches, businesses, schools, recreation, and clothing. In order to learn about the daily life of Yamhill County, we analyzed historical evidence from Yamhill County in 1912, such as newspapers, pictures, and journals. These documents were found with help from the Yamhill County Historical Museum and the McMinnville Public Library. With this evidence, we crafted together a thorough portrayal on the daily life of Yamhill County in 1912

    The Puzzle of the Antebellum Fertility Decline in the United States: New Evidence and Reconsideration

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    All nations that can be characterized as developed have undergone the demographic transition from high to low levels of fertility and mortality. Most presently developed nations began their fertility transitions in the late nineteenth or early twentieth centuries. The United States was an exception. Evidence using census-based child-woman ratios suggests that the fertility of the white population of the United States was declining from at least the year 1800. By the end of the antebellum period in 1860, child-woman ratios had declined 33 percent. There is also indication that the free black population was experiencing a fertility transition. This transition was well in advance of significant urbanization, industrialization, and mortality decline and well in advance of every other presently developed nation with the exception of France. This paper uses census data on county-level child-woman ratios to test a variety of explanations on the antebellum American fertility transition. It also uses micro data from the IPUMS files for 1850 and 1860. A number of the explanations, including the land availability hypothesis, the local labor market-child default hypothesis, and the life cycle saving hypothesis, are consistent with the data, but nuptiality, not one of the usual explanations, emerges as likely very important.

    American Indian Mortality in the Late Nineteenth Century: The Impact of Federal Assimilation Policies on a Vulnerable Population

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    Under the urging of late nineteenth-century humanitarian reformers, U.S. policy toward American Indians shifted from removal and relocation efforts to state-sponsored attempts to "civilize" Indians through allotment of tribal lands, citizenship, and forced education. There is little consensus, however, whether and to what extent federal assimilation efforts played a role in the stabilization and recovery of the American Indian population in the twentieth century. In this paper, we rely on a new IPUMS sample of the 1900 census of American Indians and census-based estimation methods to investigate the impact of federal assimilation policies on childhood mortality. We use children ever born and children surviving data included in the censuses to estimate childhood mortality and [responses to] several questions unique to the Indian enumeration [including tribal affiliation, degree of "white blood", type of dwelling, ability to speak English, and whether a citizen by allotment] to construct multivariate models of child mortality. The results suggest that mortality among American Indians in the late nineteenth century was very high - approximately 62% [standardize as % or percent throughout] higher than that for the white population. The impact of assimilation policies was mixed. Increased ability to speak English was associated with lower child mortality, while allotment of land in severalty was associated with higher mortality. The combined effect was a very modest four percent [as above] decline in mortality. As of 1900, the government campaign to assimilate Indians had yet to result in a significant decline in Indian mortality while incurring substantial economic and cultural costs.

    Measurement and analysis of lightning induced voltages in aircraft electrical systems

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    Lightning induced voltages in aircraft electrical circuit

    Building envelope design for climate change mitigation: a case study of hotels in Greece

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    This paper presents results of a study of the impact of future climate change scenarios as developed by the Intergovernmental Panel on Climate Change and implemented in weather files for specific future time slices (2020, 2050 and 2080) for the three climatic regions of Greece on the design of the external envelope of a hotel building in Greece. The impact of climate change on the hotel is assessed via hourly simulations of a calibrated model developed using the software TRNSYS. Additionally, the paper aims to identify optimal refurbishment strategies, given the constraints of the existing case-study building when transposed to the three different climatic zones in Greece. Two modes of the hotel building were studied: ‘all year’ and ‘seasonally’ operated. It was found that different external envelope energy-efficient strategies can be applied depending on the climatic zone and whether the hotel is all-year or seasonally operated

    The Design and Implementation of an AFP/AFS Protocol Translator

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    This paper gives an overview of the design and implementation of the AFP/AFS protocol translator currently in use at the University of Michigan. The protocol translator is an implementation of the AppleTalk protocol suite on BSD UNIX and BSD UNIX derivatives. The translator exploits currently existing UNIX TCP/IP mechanisms (such as sockets), and provides a programming interface to the session and transport layers of AppleTalk. The translator is designed to export AFS and UNIX local file system components as AFP volumes. This ability enables users to access files in the large AFS file system using the native Macintosh interface. Additionally, the translator software on the Macintosh provides Kerberos authentication to the AFS client (AFS Kerberos), reauthentication for expired tokens (AFS Log), and the advantages of the rich access control mechanisms provided by AFS.http://deepblue.lib.umich.edu/bitstream/2027.42/107947/1/citi-tr-93-5.pd
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