59,505 research outputs found

    Self-balancing beam permits safe, easy load handling under overhang

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    The use of a self-balancing I-beam with a counterweight and motor simplifies moving heavy loads that are inaccessible for cranes. The beam cannot be overloaded, as the counterweight will not balance the load, and thus acts as an automatic safety device

    Theoretical and experimental studies of atmospheric structure and dynamics, using high altitude chemical release, Radio meteor, and meteorological rocket network and other data

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    Data collected by the Georgia Tech Radio Meteor Wind Facility during the fall and winter of 1975 are analyzed indicating a relationship between lower thermospheric circulation at mid latitudes and polar stratospheric dynamics. Techniques of measurement of mixing processes in the upper atmosphere and the interpretation of those measurements are described along with a diffusion simulation program based on the Global Reference Atmosphere program

    Reasonableness, Murder, and Modern Science

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    Originally titled “Is It Murder in Tennessee to Kill a Chimpanzee,” this article argues in some detail that typical legal definitions of “murder” as involving the intentional killing of “a reasonable being” would require classifying the intentional killing of chimpanzees as murder

    Filtering device

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    An electrical filter for removing noise from a voice communications signal is reported; seven sample values of the signal are obtained continuously, updated and subjected to filtering. Filtering is accomplished by adding balanced, with respect to a mid-point sample, spaced pairs of the sampled values, and then multiplying each pair by a selected filter constant. The signal products thus obtained are summed to provide a filtered version of the original signal

    Now or Later?: Deciding when to Pursue a Doctorate Degree in Psychology

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    Supersonic airplane design optimization method for aerodynamic performance and low sonic boom

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    This paper presents a new methodology for the optimization of supersonic airplane designs to meet the dual design objectives of low sonic boom and high aerodynamic performance. Two sets of design parameters are used on an existing High Speed Civil Transport (HSCT) configuration to maximize the aerodynamic performance and minimize the sonic boom under the flight track. One set of the parameters perturbs the camber line of the wing sections to maximize the lift-over-drag ratio (L/D). A preliminary optimization run yielded a 3.75 percent improvement in L/D over a baseline low-boom configuration. The other set of parameters modifies the fuselage area to achieve a target F-function. Starting from an initial configuration with strong bow, wing, and tail shocks, a modified design with a flat-top signature is obtained. The methods presented can easily incorporate other design variables and objective functions. Extensions to the present capability in progress are described

    The relevance of specific csfs for stakeholders during ERP implementation: an empirical study from Oman

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    The success of ERP systems implementation is affected by the extent to which stakeholders have been prepared for the project activities and its outcomes. Stakeholders’ preparation needs change as the ERP implementation lifecycle progresses and varies across stakeholder groups. Therefore a dynamic model is needed for such preparation. However such a model needs to reflect the relevance of different CSFs to different stakeholder groups at different stages of the ERP implementation life-cycle. This study examines empirical evidence from a survey conducted in Omani organisations to determine what these individual CSFs are and how they are distributed across the ERP implementation life-cycle for different stakeholder groups. The CSFs included in the survey were derived from a structured review of literature. Purposive sampling was used to select respondents representing different ERP stakeholders groups, all respondents had both experience and knowledge of ERP implementations. The survey data are analysed and the distribution of relevant CSFs across the ERP lifecycle for the different stakeholder groups are presente

    Theory of polyzwitterion conformations

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    Conformational characteristics of polyzwitterionic molecules in aqueous solutions are investigated using the variational method. Analytical relations are derived for the radius of gyration of a single polyzwitterionic chain as a function of the chain length, electrostatic interaction strength, added salt concentration, dipole moment and degree of ionization of the zwitterionic monomers. In the absence of the small ions (counterions and coions) near the polyzwitterionic chain, attractive dipole-dipole interactions are shown to induce a collapse of the polyzwitterionic chain. However, in the presence of the small ions, the radius of gyration is shown to be an interplay of the screening of the electrostatic interactions and the counterion adsorption on the zwitterionic sites. In addition to the well-known Debye-Huckel screening of the charge-charge interactions, screening of the charge-dipole and dipole-dipole interactions are found to play important roles in determining the size of the chain. Functional forms for the screened charge-dipole and dipole-dipole interaction potentials are presented. Furthermore, counterion adsorption on the zwitterionic monomers is predicted to be asymmetric depending on the nature of the added salt and the zwitterionic groups. Qualitative remarks regarding the solubility of these molecules in aqueous solutions along with the classical "anti-polyelectrolyte" effect (increase in the solubility in water with the addition of salt) are presented.Comment: To be appeared in J. Chem. Phy

    Theoretical and experimental investigations of upper atmosphere dynamics

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    A brief overview of the significant contributions made to the understanding of the dynamics of the Earth's upper atmosphere is presented, including the addition of winds and diffusion to the semi-empirical Global Reference Atmospheric Model developed for the design phase of the Space Shuttle, reviews of turbulence in the lower thermosphere, the dynamics of the equatorial mesopause, stratospheric warming effects on mesopause level dynamics, and the relevance of these studies to the proposed Middle Atmosphere Program (1982-85). A chronological bibliography, with abstracts of all papers published, is also included
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