439 research outputs found

    Effective Use of Microcomputers for Elementary Social Studies

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    The use of computers in the classroom is still a very new development in education. In fact, computers themselves have been around only for about thirty-five years. The incredible growth in the technology of computers is almost impossible to fathom. Modern computers are not only a faster and smarter, they are smaller and cheaper. Shane (1982) pointed out that if a Rolls Royce had become as cost effective as computers and had its price reduced accordingly, it would cost only three dollars

    Development of Design Guidelines for CIP Joint Connections with U-bar Reinforcement

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    The interstate highway system is vitally dependent upon current and future bridges. These bridges must be designed economically to continue the serviceability with limited maintenance. For precast bridge construction a portion of the design must consider the bridge connections. Some current connections have proved insufficient in serviceability as there is uncontrolled cracking. In other connections there are uncertainties in the calculations (or lack of calculations) which require design guidelines. This thesis presents design recommendations for precast decking u-bar reinforcement in tension which results from negative moment over a pier. Testing results from the University of Tennessee were analyzed to determine the design recommendations. The calculated capacity of the specimens was determined first by strut and tie modeling by AASHTO and ACI, but was shown to be insufficient. Proposed changes to the current calculation of the strut width as specified in AASHTO and ACI STM methods were discussed in order to match the test results. However, strut and tie modeling demonstrated that the design for the lacer bar was inadequate. Since the strut and tie modeling method resulted in an inaccurate lacer bar size, another method was developed. A triangular shape develops from the flow of forces in the connection joint zone; as a result, a free body diagram (FBD) was developed from the concrete triangular shape. This diagram showed how the forces flow in the in-situ joint as well as how they are resisted. A formula was developed from the FBD to determine the capacity of the joint which accurately reflected the capacities from tests. A FBD was also made of the lacer bar utilizing the forces and geometry calculated from the capacity calculations. A computer analysis program was used to determine the forces in the lacer bar. The lacer bar could then be designed since the required forces to resist (moment and shear) were known. A comparison of the strut and tie model to the triangular method led to the conclusion that both can determine the longitudinal reinforcement spacing, joint overlap length, and concrete strength, but only the triangular method can determine a more sufficient lacer bar size

    Getting the Political Architecture Right

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    As Australia approaches the twenty-first century, it finds itself, like a number of other Anglo-centred countries in the western world, including Canada, in the grip of continuing economic trauma. There has been a marked relative (and absolute) slip in general economic performance. This paper focuses on the linkages between this phenomenon and Australia\u27s basic political architecture. It argues that, although renovation of Australian federalism is no panacea for these problems, there are linkages between Australia\u27s aged, formal, political structure and its recent economic performance. Lack of attention to the task of serious, systematic renovation is allowing the present outdated political structure to aggravate economic and social problems. The article concludes that a much more adventurous, long-term approach to the renovation of Australia\u27s political architecture is needed

    Italian surnames in the Family Names of the United Kingdom project

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    An overview of surnames of Italian origin treated in the Family Names of the United Kingdom project

    An array of strong-motion accelerographs in Bear Valley, California

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    Fifteen strong-motion accelerographs, each with the capability of writing the WWVB absolute time code on the recorded accelerogram, have been deployed in an elliptical array, at a station spacing of several kilometers, along the San Andreas Fault in the Bear Valley region of central California. Ten accelerograms were obtained for the June 22, 1973, earthquake (M = 3.9), located near the center of the array. Preliminary analyses of these accelerograms support previous suggestions that the crystalline rocks of the Gabilan Range possess higher material velocities and lower intrinsic absorption than do the Cretaceous and Cenozoic sedimentary rocks northeast of the fault zone. These accelerograms clearly indicate that a strong-motion accelerograph array of this sort can provide the basic data for source mechanism, wave propagation, and local ground-motion studies for earthquakes with magnitudes as small as 3.5-4.0

    Project Minerva: A low cost manned Mars mission based on indigenous propellant production

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    Project Minerva is a low-cost manned Mars mission designed to deliver a crew of four to the Martian surface using only two sets of two launches from the Kennedy Space Center. Key concepts which make this mission realizable are the use of near-term technologies and in-situ propellant production, following the scenario originally proposed by R. Zubrin. The first set of launches delivers two unmanned payloads into low Earth orbit (LEO): the first payload consists of an Earth Return Vehicle (ERV), a propellant production plant, and a set of robotic vehicles; the second payload consists of the trans-Mars injection (TMI) upper stage. In LEO, the two payloads are docked and the configuration is injected into a Mars transfer orbit. The landing on Mars is performed with the aid of multiple aerobraking maneuvers. On the Martian surface, the propellant production plant uses a Sabatier/electrolysis type process to combine nine tons of hydrogen with carbon dioxide from the Martian atmosphere to produce over a hundred tons of liquid oxygen and liquid methane, which are later used as the propellants for the rover expeditions and the manned return journey of the ERV. The systems necessary for the flights to and from Mars, as well as those needed for the stay on Mars, are discussed. These systems include the transfer vehicle design, life support, guidance and communications, rovers and telepresence, power generation, and propellant manufacturing. Also included are the orbital mechanics, the scientific goals, and the estimated mission costs

    Simulating the Gradually Deteriorating Performance of an RTG

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    Degra (now in version 3) is a computer program that simulates the performance of a radioisotope thermoelectric generator (RTG) over its lifetime. Degra is provided with a graphical user interface that is used to edit input parameters that describe the initial state of the RTG and the time-varying loads and environment to which it will be exposed. Performance is computed by modeling the flows of heat from the radioactive source and through the thermocouples, also allowing for losses, to determine the temperature drop across the thermocouples. This temperature drop is used to determine the open-circuit voltage, electrical resistance, and thermal conductance of the thermocouples. Output power can then be computed by relating the open-circuit voltage and the electrical resistance of the thermocouples to a specified time-varying load voltage. Degra accounts for the gradual deterioration of performance attributable primarily to decay of the radioactive source and secondarily to gradual deterioration of the thermoelectric material. To provide guidance to an RTG designer, given a minimum of input, Degra computes the dimensions, masses, and thermal conductances of important internal structures as well as the overall external dimensions and total mass

    The Family Name as Socio-Cultural Feature and Genetic Metaphor: From Concepts to Methods

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    A recent workshop entitled The Family Name as Socio-Cultural Feature and Genetic Metaphor: From Concepts to Methods was held in Paris in December 2010, sponsored by the French National Centre for Scientific Research (CNRS) and by the journal Human Biology. This workshop was intended to foster a debate on questions related to the family names and to compare different multidisciplinary approaches involving geneticists, historians, geographers, sociologists and social anthropologists. This collective paper presents a collection of selected communications
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