6,528 research outputs found

    Preliminary investigation of pressure influence on multiphase heat transfer report no. ii

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    Pressure and surface condition in multiphase boiling heat transfe

    Thermal conductivity of comets

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    A value is described for the thermal conductivity of the frost layer and for the water-ice solid debris mixture. The value of the porous structure is discussed as a function of depth only. Graphs show thermal conductivity as a function of depth and temperature at constant porosity and density

    Saturated system behavior - Surface boiling and controlled blowdown Final report

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    Surface and static pressure effects on nucleate pool boiling, and depressurization response of saturated syste

    Interaction between functional domains of Bacillus thuringiensis insecticidal crystal proteins

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    Interactions among the three structural domains of Bacillus 1huringiensis Cn.l toxins %~ere investigated by functional analysis of chinieric proteins. Hybrid genes were prepared by exchanging the regions coding for either domain 1 or domain III among CrylAb, Cn,lAc, CrylC, and CrylE. The activity of the purified trypsinactivated chimeric toxins was evaluiated by testing their effects on the viability and plasma membrane permeability of Sf9 cells. Among the parental toxins, only CrylC was active against these cells and only chimeras possessing domain II from CrylC were functional. Combination of domain 1 from CrylE Niith domains Il and III from CrylC, however, resulted in an inactive toxin, indicating that domain II from an active toxin is necessary, but not sufficient, for activity. Pores formed by chimeric toxins in which domain I was frorn Cr31M or CrylAc were slightly smaller than those formed by toxins in which domain I was from CrylC. The properties of the pores formed by the chimeras are therefore likely to result froin an interaction between domain I and domain II or 111. Domain III appears to modulate the activity of the chimeric toxins: combination of domain 111 from CrylAb with domains 1 and II of CrylC gave a protein which was more strongly active than CrylC. (Résumé d'auteur

    Pool boiling of water from mechanically polished and chemically etched stainless steel surfaces

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    Nucleate boiling heat transfer from mechanically polished, chemically etched stainless steel boiling plat

    Thermal conductivity of heterogeneous mixtures and lunar soils

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    The theoretical evaluation of the effective thermal conductivity of granular materials is discussed with emphasis upon the heat transport properties of lunar soil. The following types of models are compared: probabilistic, parallel isotherm, stochastic, lunar, and a model based on nonlinear heat flow system synthesis

    Local Flow Conditions for Propulsion Experiments on the NASA F-15B Propulsion Flight Test Fixture

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    Local flow conditions were measured underneath the National Aeronautics and Space Administration F-15B airplane to support development of future experiments on the Propulsion Flight Test Fixture (PFTF). The local Mach number and flow angles were measured using a conventional air data boom on a cone-cylinder mounted under the PFTF and compared with the airplane air data nose boom measurements. At subsonic flight speeds, the airplane and PFTF Mach numbers were approximately equal. Transonic Mach number values were up to 0.1 greater at the PFTF than the airplane, which is a counterintuitive result. The PFTF local supersonic Mach numbers were as much as 0.46 less than the airplane values. The maximum local Mach number at the PFTF was approximately 1.6 at an airplane Mach number near 2.0. The PFTF local angle of attack was negative at all Mach numbers, ranging from -3 to -8 degrees. When the airplane angle of sideslip was zero, the PFTF local value was zero between Mach 0.8 and Mach 1.1, -2 degrees between Mach 1.1 and Mach 1.5, and increased from zero to 1 degree from Mach 1.5 to Mach 2.0. Airplane inlet shock waves crossed the aerodynamic interface plane between Mach 1.85 and Mach 1.90

    Development and Characterisation of a Gas System and its Associated Slow-Control System for an ATLAS Small-Strip Thin Gap Chamber Testing Facility

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    A quality assurance and performance qualification laboratory was built at McGill University for the Canadian-made small-strip Thin Gap Chamber (sTGC) muon detectors produced for the 2019-2020 ATLAS experiment muon spectrometer upgrade. The facility uses cosmic rays as a muon source to ionise the quenching gas mixture of pentane and carbon dioxide flowing through the sTGC detector. A gas system was developed and characterised for this purpose, with a simple and efficient gas condenser design utilizing a Peltier thermoelectric cooler (TEC). The gas system was tested to provide the desired 45 vol% pentane concentration. For continuous operations, a state-machine system was implemented with alerting and remote monitoring features to run all cosmic-ray data-acquisition associated slow-control systems, such as high/low voltage, gas system and environmental monitoring, in a safe and continuous mode, even in the absence of an operator.Comment: 23 pages, LaTeX, 14 figures, 4 tables, proof corrections for Journal of Instrumentation (JINST), including corrected Fig. 8b

    Vortex lattice stability in the SO(5) model

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    We study the energetics of superconducting vortices in the SO(5) model for high-TcT_c materials proposed by Zhang. We show that for a wide range of parameters normally corresponding to type II superconductivity, the free energy per unit flux \FF(m) of a vortex with mm flux quanta is a decreasing function of mm, provided the doping is close to its critical value. This implies that the Abrikosov lattice is unstable, a behaviour typical of type I superconductors. For dopings far from the critical value, \FF(m) can become very flat, indicating a less rigid vortex lattice, which would melt at a lower temperature than expected for a BCS superconductor.Comment: 4 pp, revtex, 5 figure
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