9,013 research outputs found

    NASA Contributions to Development of Special-Purpose Thermocouples. A Survey

    Get PDF
    The thermocouple has been used for measuring temperatures for more than a century, but new materials, probe designs, and techniques are continually being developed. Numerous contributions have been made by the National Aeronautics and Space Administration and its contractors in the aerospace program. These contributions have been collected by Midwest Research Institute and reported in this publication to enable American industrial engineers to study them and adapt them to their own problem areas. Potential applications are suggested to stimulate ideas on how these contributions can be used

    Do shareholders of acquiring firms gain from acquisitions?

    Get PDF
    We examine a sample of 12,023 acquisitions by public firms from 1980 to 2001. Shareholders of these firms lost a total of 218billionwhenacquisitionswereannounced.Thoughshareholderslosethroughoutoursampleperiod,lossesassociatedwithacquisitionannouncementsafter1997aredramatic.Smallfirmsgainfromacquisitions,sothatshareholdersofsmallfirmsgained218 billion when acquisitions were announced. Though shareholders lose throughout our sample period, losses associated with acquisition announcements after 1997 are dramatic. Small firms gain from acquisitions, so that shareholders of small firms gained 8 billion when acquisitions were announced and shareholders of large firms lost $226 billion. We examine the cross-sectional variation in the announcement returns of acquisitions. Small firm shareholders earn systematically more when acquisitions are announced. This size effect is typically more important than how an acquisition is financed and than the organizational form of the assets acquired. The only acquisitions that have positive aggregate gains are acquisitions of subsidiaries.

    Measurements of Temperature Dependency on Thermal Insulation Thickness in Ventilated Attics

    Get PDF
    The main objective of this paper is by measurements to investigate whether increased thermal insulation thickness reduces the temperature in ventilated attics. With lower heat flux through the ceiling in the winter, the theory is that the temperature in the attic decreases and consequently the relative humidity increases which may cause mold growth. While some simulations support this theory, others do not. To test the theory in practice, measurements were performed in 29 dwellings, mainly older single family houses with ventilated attics and insulation thicknesses varying between 150 and 600 mm (6“ and 23“). The temperature was measured for more than one year in the attic, the living space below and outdoors. All measured attics were ventilated as recommended in guidelines; i.e. with openings at the top and the bottom. The measurements in the attics showed high dependency on the outdoor temperature, while indoor temperature and the thickness of insulation were not significant. Consequently, the thermal insulation thickness alone cannot explain possible increasing mold problems. However, extra insulation in attics may obstruct the ventilation openings and therefore, reduce the ventilation rate. Measurements of ventilation rates in non-problematic and moldy attics should therefore be the next step

    Toward Open-Closed String Theoretical Description of Rolling Tachyon

    Full text link
    We consider how the time-dependent decay process of an unstable D-brane should be described in the full (quantum) open-closed string theory. It is argued that the system, starting from the unstable D-brane configuration, will evolve in time into the time-independent open string tachyon vacuum configuration which we assume to be finite, with the total energy conserved. As a concrete realization of this idea, we construct a toy model describing the open and closed string tachyons which admits such a time-dependent solution. The structure of our model has some resemblance to that of open-closed string field theory.Comment: 1+10 pages, 6 figures. v2: a reference adde

    On p-Adic Sector of Adelic String

    Full text link
    We consider construction of Lagrangians which are candidates for p-adic sector of an adelic open scalar string. Such Lagrangians have their origin in Lagrangian for a single p-adic string and contain the Riemann zeta function with the d'Alembertian in its argument. In particular, we present a new Lagrangian obtained by an additive approach which takes into account all p-adic Lagrangians. The very attractive feature of this new Lagrangian is that it is an analytic function of the d'Alembertian. Investigation of the field theory with Riemann zeta function is interesting in itself as well.Comment: 10 pages. Presented at the 2nd Conf. on SFT and Related Topics, Moscow, April 2009. Submitted to Theor. Math. Phy

    Nonlocal Dynamics of p-Adic Strings

    Full text link
    We consider the construction of Lagrangians that might be suitable for describing the entire pp-adic sector of an adelic open scalar string. These Lagrangians are constructed using the Lagrangian for pp-adic strings with an arbitrary prime number pp. They contain space-time nonlocality because of the d'Alembertian in argument of the Riemann zeta function. We present a brief review and some new results.Comment: 8 page
    • …
    corecore