[en] The lubrication of materials at elevated temperatures is one of the primary barriers to the successful development of advanced heat engines. Such engines are being designed to operate at higher temperatures to attain higher efficiencies. In the near future, designs requiring liquid lubricants capable of sustained operation at temperatures in the range 300 degree C to 500 degree C can be expected. Such lubricants may also have applications in bearing systems where the objective is longer service life rather than higher operating temperatures. In both applications, oxidation reactions limit the capabilities of the lubricant. Consequently, producing a greater stability against oxidative degradation is one of the primary goals of lubrication research. The present paper investigates the potential for producing a lubricating basestock in which the oxidative stability has been improved by means of the process of deuteration. An alternative to the conventional chemical synthesis of deuterated materials is to employ microorganisms adapted to growth in pure deuterium oxide (D₂O). Possible advantages are lower costs, greater ease of production, and assurance of complete deuteration compared to conventional hydrogen-deuterium exchange reactions employing high temperatures, prolonged reaction times, and proprietary catalysts. The biosynthetic approach may also make possible the synthesis of deuterated compounds too labile for chemical synthetic methods. In this investigation algal species and growth conditions in 100% D₂O were sought which would result in large amounts of fatty acids suitable for synthesis of deuterated lubricants. Possible routes of synthesis of deuterated tetrahexanoate esters of pentaerythritol were explored. Tests for high temperature resistance to oxidation, friction and ware were made on the deuterated product made from algal lipids and compared with results on the hydrogen analog

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[en] Valence-band photoemission spectra of Ni₃Al, Ni₃Ga and Ni₃In were measured with synchrotron radiation at photon energies around the Ni-3p core excitation threshold. The valence-band satellites are resonantly enhanced. The number of holes per Ni atom in the Ni-D band for Ni₃Al, Ni₃Ga and Ni₃In is estimated to be 0.37, 0.30 and 0.34, respectively. The self-energy correction due to the configuration interaction is 0.72, 0.71 and 0.72 eV, respectively, for Ni₃Al, Ni₃Ga and Ni₃In. The Fano parameters and the effective Coulomb interactions between two 3D holes for these intermetallic compounds are determined

[en] We have searched for the pair produced charged Higgs particles in the decays of Z⁰ for the decay channels of H⁺H^-→τ⁺ντ^-anti ν, H⁺H^-→τνcs and H⁺H^-→canti santi cs. The data sample analyzed corresponds to approximately 50 000 hadronic decays of Z⁰. A lower limit of 36.5 GeV is obtained at the 95% confidence level for the mass of charged Higgs particle, independent of its decay branching ratio. (orig.)

[en] We have searched for excited taus from Z⁰ decay in the channels e⁺e^-→τ*⁺τ*^-→τ⁺τ^-γγ and e⁺e^-→ττ*→τ⁺τ^-γ, using the L3 detector at LEP. Using the τ* pair production channel, we can exclude a τ* up to a mass of 45.5 GeV at 95% confidence level. We have also determined upper limits on the ττ*Z⁰ and ττ*γ couplings as a function of m_τ* up to 89.3 GeV. (orig.)

[en] We have searched for lepton flavour violation in Z⁰ boson decays into lepton pairs, Z⁰→μτ, Z⁰→eτ, and Z^-→eμ. The data sample is based on an integrated luminosity of 10.4 pb^-1 corresponding to 370 000 Z⁰'s produced. We obtain upper limits on the branching ratios of 4.8x10^-5 for the μτ, 3.4x10^-5 for the eτ and 2.4x10^-5 for the eμ decay modes at the 95% confidence level. (orig.)

[en] We have measured the partial widths for the three reactions e⁺e^-→Z⁰→e⁺e^-, μ⁺μ^-, τ⁺τ^-. The results are Γ_ee=84.3±1.3 MeV, √Γ_eeΓ_μμ=83.3±1.3 MeV, and √Γ_eeΓ_ττ=83.9±1.4 MeV, where the errors are statistical. The systematic errors are estimated to be 1.0 MeV, 0.9 MeV, and 1.4 MeV, respectively. We perform a simultaneous fit to the cross sections for the e⁺e^-→e⁺e^-, μ⁺μ^-, and τ⁺τ^- data, the differential cross section as a function of polar angle for the electron data, and the forward-backward asymmetry for the muon data. We obtain the leptonic partial with Γ_ll=84.0±0.9(stat). MeV. The systematic error is estimated to be 0.8 MeV. Also, we obtain the axial-vector and vector weak coupling constants of charged leptons, g_A=-0.500±0.003 and g_V=-0.064_-0.013^+0.017. (orig.)

[en] We have measured the cross-section of the reaction e⁺e^-→γγ at center of mass energies around the Z⁰ mass. The results are in good agreement with QED predictions. For the QED cutoff parameters the limit of Λ₊>103 GeV and Λ_->118 GeV are found. For the decays Z⁰→γγ, Z⁰→π⁰γ, Z⁰→ηγ and Z⁰→γγγ we find upper limits of 2.9x10^-4, 2.9x10^-4, 4.1x10^-4 and 1.2x10^-4, respectively. All limits are at 95% CL. (orig.)

[en] We have searched for the neutral Higgs boson produced in the decays of the Z⁰ through the process Z⁰→H⁰l⁺l^- in the mass range Msub(H⁰)<2 GeV. From the analysis of a data sample corresponding to about 70 000 Z⁰→hadrons we exclude a minimal standard model Higgs boson in the mass range 0< Msub(H⁰)<2 GeV at the 99% confidence level independent of the Higgs decay channels. (orig.)