21,617 research outputs found

    Device measures reaction engine thrust vector deviations

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    Gimbal mounted test device measures thrust vector deviation of reaction engines in terms of angular displacement and thus precludes force interaction

    Technology Transfer, Foreign Direct Investment and International Trade

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    By developing a Ricardian trade model that features technology transfer via foreign direct investment (FDI), we show that technology transfer via multinational enterprises (MNEs) increases world output and trade in goods and services. When there are many goods a continuous reduction in the cost of technology transfer will cause increasingly more technologically advanced goods to go through the product cycle, i.e., goods initially produced in the advanced North are later produced in the backward South as a result of increased technology transfer via MNEs.

    Astrophysical Observations of Early Universe Phase Transitions

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    After a review of CMBR correlations and recent observations, a study of possible CMBR observations of the QCD early universe phase transition is discussed. A model for the QCD bubble walls gives the surface tension found in lattice calculations, and a 1+1 dimensional treatment in this model for bubble collisions shows an interior gluonic wall, a disk with the thickness of a nucleon and horizon size radius. This could lead to a similar magnetic wall, which would produce B-B type CMBR polarization correlations distinct from very early universe models. The study of magnetic fields produced in bubble collisions in MSSM models with a first order Electroweak Phase Transition is also discussed.Comment: 8 pages with 2 figures. Contribution to the CosPA 2003 Cosmology and Particle Astrophysics Symposiu

    The MinK Potassium Channel Exists in Functional and Nonfunctional Forms When Expressed in the Plasma Membrane of \u3cem\u3eXenopus\u3c/em\u3e Oocytes

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    The minK protein induces a slowly activating voltage-dependent potassium current when expressed in Xenopus oocytes. In order to measure the levels of minK protein in the plasma membrane, we have modified the minK gene by inserting a 9 amino acid epitope into the N- terminal domain of the protein sequence. When intact live oocytes are injected with the modified minK RNA and subsequently incubated with an antibody to this epitope, specific binding is detected, indicating that the N-terminal domain is extracellular. We found that when oocytes are injected with amounts of minK mRNA up to 50 ng, the levels of protein at the surface are proportional to the amount of injected mRNA. In contrast, the amplitude of the minK current recorded in the oocytes saturates at 1 ng of injected mRNA. Although the amplitude of the currents is not altered by increasing mRNA levels above 1 ng, the kinetics of activation of the current differ in oocytes with high or low levels of minK RNA. In particular, activation is slower with higher levels of minK protein in the plasma membrane. Finally, we find that increasing intracellular cAMP levels, which increases the amplitude of minK currents, does not alter surface expression of the minK protein but produces a small increase in the rate of activation of the current. Our results support a model in which minK protein forms functional potassium channels by association with a factor endogenous to the oocyte

    Alignment apparatus using a laser having a gravitationally sensitive cavity reflector

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    A description is given of a device for determining a true gravitational vertical. The apparatus is composed of a vertically disposed laser with a gravitationally sensitive lower regeneration reflector. The reflector enables an output beam to be developed only when the optical axis of the laser is disposed normal to the gravitationally sensitive reflective surface. In an alternative embodiment, the devices is combined with a servo system to provide a gravitationally stabilized horizontal platform

    Modulation by cAMP of a Slowly Activating Potassium Channel Expressed in \u3cem\u3eXenopus\u3c/em\u3e Oocytes

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    When expressed in the Xenopus oocyte, the minK protein induces a slowly activating voltage-dependent potassium current (Isk). We studied the modulation of this current by altering intracellular cAMP levels and found that the amplitude of Isk is dramatically increased by treatments that raise cAMP levels and decreased by agents that lower cAMP levels. Preinjection of a protein inhibitor of the cAMP-dependent protein kinase blocked the effects of increased cAMP levels. There were no changes in the voltage dependence or kinetics of Isk. Mutations that eliminate a potential phosphorylation site on the minK protein did not block the effects of activating the kinase. In addition, the membrane capacitance of the oocyte increased and decreased in parallel with Isk. Our results fit a mechanism in which channel proteins are selectively inserted into and removed from the plasma membrane in response to changes in kinase activity

    The Lewis Heat Pipe Code with Application to SP-100 GES Heat Pipes

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    The NASA Lewis Research Center has a thermal management program supporting SP-100 goals, which includes heat pipe radiator development. As a part of the program Lewis has elected to prepare an in-house heat pipe code tailored to the needs of its SP-100 staff to supplement codes from other sources. The latter, designed to meet the needs of the originating organizations, were deemed not entirely appropriate for use at Lewis. However, a review of their features proved most beneficial in the design of the Lewis code

    Controlled vortical flow on delta wings through unsteady leading edge blowing

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    The vortical flow over a delta wing contributes an important part of the lift - the so called nonlinear lift. Controlling this vortical flow with its favorable influence would enhance aircraft maneuverability at high angle of attack. Several previous studies have shown that control of the vortical flow field is possible through the use of blowing jets. The present experimental research studies vortical flow control by applying a new blowing scheme to the rounded leading edge of a delta wing; this blowing scheme is called Tangential Leading Edge Blowing (TLEB). Vortical flow response both to steady blowing and to unsteady blowing is investigated. It is found that TLEB can redevelop stable, strong vortices even in the post-stall angle of attack regime. Analysis of the steady data shows that the effect of leading edge blowing can be interpreted as an effective change in angle of attack. The examination of the fundamental time scales for vortical flow re-organization after the application of blowing for different initial states of the flow field is studied. Different time scales for flow re-organization are shown to depend upon the effective angle of attack. A faster response time can be achieved at angles of attack beyond stall by a suitable choice of the initial blowing momentum strength. Consequently, TLEB shows the potential of controlling the vortical flow over a wide range of angles of attack; i.e., in both for pre-stall and post-stall conditions
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