Differential stiffness effects

Differential stiffness as developed in NASTRAN is a linear change in stiffness caused by applied loads. Examples of differential stiffness are the stiffening effects of gravity forces in a pendulum, centrifugal forces in rotor blades and pressure loading of shell structures. In cases wherein this stiffness caused by a load is destabilizing, the differential stiffness concept lends itself to nonlinear structural analysis. Rigid Formats 4 (static analysis with differential stiffness) and 13 (normal modes with differential stiffness) are specifically designed to account for such stiffness changes. How pressure loading may be treated in these rigid formats is clarified. This clarification results from modal correlation of Ground Vibration Test (GVT) results from the empty and pressurized Filament Wound Case (FWC) quarter-scale Space Shuttle solid rocket booster (QSSRB). A sketch of the QSSRB cantilevered to the floor by its external tank attachments is shown

Wind field analysis for cantilever loads

Numerical analysis to determine interference effects in local wind flow about Saturn 5 launcher umbilical towe

Simulated High Reynolds Number Flow About a Circular Cylinder Final Report

Numerical analysis method for solving problem of high Reynolds number flow around circular cylinder based on potential theory and influence coefficients using Cartesian grid syste

Technology Development Center at NICT

The National Institute of Information and Communications Technology (NICT) is developing and testing VLBI technologies and conducts observations with this new equipment. This report gives an overview of the Technology Development Center (TDC) at NICT and summarizes recent activities

In-situ growth of superconducting NdFeAs(O,F) thin films by Molecular Beam Epitaxy

The recently discovered high temperature superconductor F-doped LaFeAsO and related compounds represent a new class of superconductors with the highest transition temperature (Tc) apart from the cuprates. The studies ongoing worldwide are revealing that these Fe-based superconductors are forming a unique class of materials that are interesting from the viewpoint of applications. To exploit the high potential of the Fe-based superconductors for device applications, it is indispensable to establish a process that enables the growth of high quality thin films. Efforts of thin film preparation started soon after the discovery of Fe-based superconductors, but none of the earlier attempts had succeeded in an in-situ growth of a superconducting film of LnFeAs(O,F) (Ln=lanthanide), which exhibits the highest Tc to date among the Fe-based superconductors. Here, we report on the successful growth of NdFeAs(O,F) thin films on GaAs substrates, which showed well-defined superconducting transitions up to 48 K without the need of an ex-situ heat treatment

Flow Patterns of Liquid in a Cylindrical Mixing Vessel without Baffles

The velocity distribution of agitated liquid in a cylindrical mixing vessel was measured by using a set of pitot tubes, the construction of which is shown in Fig. 2. Some of the experimental results are shown in Figs. 4, 5, 6, 7, 8, 9 and 10. As a result, the flow patterns in an agitated vessel were made clear and it was ascertained that, in addition to the primary circulation flow around the impeller axis, there was a secondary circulation of liquid ensued by the discharge flow from the tip of an impeller as shown in Figs. 8 and 10. Integrating the measured velocity distributions, the discharge flow rates of impellers were determined and the discharging performance of various impellers (refer to Table 1) was compared in connection with the power consumption. Dimensionless factor, Nq₁, was defined and was called the coefficient of discharge. The ratio, Np/Nq₁ in Table 3, corresponds to the relative power required for a unit quantity of discharge. Furthermore, the power consumption in the neighbourhood of an impeller (Nᴘᵢₘₚ), in other words, in the cylindrical domain (refer to hatched region in Fig. 14) was calculated and compared with that consumed in the outer region of the vessel as shown in Table 4. It is concluded that the improvement in the discharging capacity can be accomplished to some extent by the proper design of an impeller ; however, the fundamental improvement must rely upon some other method

Identification of a novel type of polyunsaturated fatty acid synthase involved in arachidonic acid biosynthesis

AbstractArachidonic acid (ARA) is a polyunsaturated fatty acid (PUFA) and an essential component of membrane lipids. However, the PUFA synthase required for ARA biosynthesis has not been identified in any organism. To identify the PUFA synthase producing ARA, we determined the draft genome sequence of the marine bacterium Aureispira marina, which produces a high level of ARA, and found a gene cluster encoding a putative PUFA synthase for ARA production. Expression of the gene cluster in Escherichia coli induced production of ARA, demonstrating that the gene cluster encodes a PUFA synthase required for ARA biosynthesis