1,198 research outputs found

    Solvent residue content measured by light scattering technique

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    Photometric analyzer measures NVR /nonvolatile residue/ in trichloroethylene and other organic solvents. The analyzer converts the liquid solvent to aerosol and passes it between an optically focused light beam and a photodetector that is connected to standard amplifying and readout equipment

    A new coordinate transformation for turbulent boundary layer flows

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    The transformation permits a uniform mesh to be used in the computational coordinate which extends across the layer. This coordinate transformation uses the local value of the skin friction coefficient to scale the thickness of the wall layer region, and the local maximum value of turbulent viscosity to scale the boundary-layer thickness. Results are presented for two dimensional boundary layers in both positive and negative pressure gradients and comparisons are made with experimental data and conventional variable-grid results for low speed turbulent boundary-layers. The cases chosen illustrate the capability of this new transformation to capture the boundary layer growth over the full extent of laminar, transitional, and turbulent flow with no grid adjustment as well as its ability to consistently enlarge the wall layer region for accurate shear stress representation. Results of mesh refinement studies using the new coordinate transformation are presented

    Very long optical path-length from a compact multi-pass cell

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    The multiple-pass optical cell is an important tool for laser absorption spectroscopy and its many applications. For most practical applications, such as trace-gas detection, a compact and robust design is essential. Here we report an investigation into a multi-pass cell design based on a pair of cylindrical mirrors, with a particular focus on achieving very long optical paths. We demonstrate a path-length of 50.31 m in a cell with 40 mm diameter mirrors spaced 88.9 mm apart - a 3-fold increase over the previously reported longest path-length obtained with this type of cell configuration. We characterize the mechanical stability of the cell and describe the practical conditions necessary to achieve very long path-lengths

    Standardization and the democratic design of information and communication technology

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    The way information and communication technology (ICT) develops can promote or hinder the democratic potential of this critical societal infrastructure. Concerns about the role standards development organizations (SDOs) play in this context predate the "digital age" but are reemerging amid substantial changes in the institutional landscape of standardization. This article explores the increasingly critical link between the institutional design of SDOs and the democratic design of ICT. We review some principles of democracy in terms of the design of technology, apply these to standardization, and discuss the role public policy may play here, while distinguishing between input and output legitimacy

    CP-Violation in Bosonic Sector of SM with two Higgs Doublets

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    We investigate CP-violation effects in the bosonic sector of the Standard Model (SM) with two Higgs doublets. First we calculate the mass eigenstates of the physical neutral Higgses for small but nonzero CP-violation parameter ξ\xi_{\ast}, and then a ``forward-backward'' asymmetry Afb{\cal A}_{fb} for the decay HW+WZH \to W^+W^-Z that would be a signal of CP-violation. Although the effects are in general small (Afb=Γfb/ΓO(103){\cal A}_{fb} = \Gamma_{fb}/\Gamma \sim {\cal O}(10^{-3})), Afb{\cal A}_{fb} turns out to be a rather clean signal of CP-violation, since neither the CP-conserving final state interactions nor the direct production background events contribute to Γfb\Gamma_{fb}. The process is a counterexample to the widespread belief that CP-violation processes must involve fermions. The CKM-type CP-violation effects that could in principle also contribute to Afb{\cal A}_{fb} are negligible. The nonzero Afb{\cal A}_{fb} could possibly be detected at some later stage in future colliders such as LHC or SSC.Comment: 11 pages (standard LaTeX), 3 figures (available from the author), DO-TH 93-1
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