1,582 research outputs found
Jordanian Solutions of Simplex Equations
We construct for all a solution of the Frenkel--Moore --simplex
equation which generalizes the --matrix for the Jordanian quantum group.Comment: 6 page
Radiometric absolute noise-temperature measurement system features improved accuracy and calibration ease
Radiometric receiver system, which measures noise temperatures in degrees Kelvin, does not require cryogenic noise sources for routine operation. It eliminates radiometer calibration errors associated with RF attenuation measurements. Calibrated noise source is required only for laboratory adjustment and calibration
Optimization of microwave radiometric systems for earth resource surveys Final report
Optimization of passive microwave radiometric systems for earth resource surveys from ground and aircraft based measurement
Toxic Hazards Research Unit annual technical report, 1969 Final report, Jun. 1968 - May 1969
Apollo materials toxicity screening tests and effects of ethylene glycol, monomethylhydrazine, NF3, OF2, and ClF
An Ecumenist of the Spirit: The Legacy of David Charles Mainse
The paper attempts to explore the career and ministry of David Mainse  as a link between classical Canadian Pentecostalism and the Charismatic Renewal.  Evidence is provided of David's upbringing, character and strategic evangelism initiatives that permitted him to remain loyal to his own denominational roots while endearing himself to a wide range mainstream and Charismatic expressions
Method and means for providing an absolute power measurement capability Patent
Input radio frequency circuit for switching type absolute temperature measuring radiometer for noise source
Substituent effects on the mechanochemical response of zinc dialkyldithiophosphate
Mechanochemistry is known to play a key role in the function of some lubricant additives, such as the tribofilm growth of zinc dialkyldithiophosphate (ZDDP). This raises the intriguing possibility of tailoring the mechanochemical response of additives by modifying their alkyl substituents. Here, we study the tribofilm formation rate of ZDDPs containing several different alkyl groups on steel surfaces from a high-friction base oil. We use macroscale tribometer experiments under full-film elastohydrodynamic lubrication conditions to enable careful control of the temperature and stress during tribofilm growth. We show how the chain length and the presence of branches or bulky cycloaliphatic groups can lead to large differences in the temperature- and stress-dependencies of the tribofilm formation rate, which can be explained through variations in packing density, steric hindrance, and stress transmission efficiency. Our rate data are successfully fitted using the Bell model; a simple modification of the Arrhenius equation that is commonly employed to model the kinetics of mechanochemical processes. Using this model, we observe large differences in the activation energy, pre-exponential factor, and activation volume for the various ZDDPs. Our findings show how structure–performance relationships can be identified for lubricant additives, which may be useful to optimise their molecular structure
Shear heating, flow, and friction of confined molecular fluids at high pressure
Understanding the molecular-scale behavior of fluids confined and sheared between solid surfaces is important for many applications, particularly tribology where this often governs the macroscopic frictional response. In this study, nonequilibrium molecular dynamics simulations are performed to investigate the effects of fluid and surface properties on the spatially resolved temperature and flow profiles, as well as friction. The severe pressure and shear rate conditions studied are representative of the elastohydrodynamic lubrication regime. In agreement with tribology experiments, flexible lubricant molecules give low friction, which increases linearly with logarithmic shear rate, while bulky traction fluids show higher friction, but a weaker shear rate dependence. Compared to lubricants, traction fluids show more significant shear heating and stronger shear localization. Models developed for macroscopic systems can be used to describe both the spatially resolved temperature profile shape and the mean film temperature rise. The thermal conductivity of the fluids increases with pressure and is significantly higher for lubricants compared to traction fluids, in agreement with experimental results. In a subset of simulations, the efficiency of the thermostat in one of the surfaces is reduced to represent surfaces with lower thermal conductivity. For these unsymmetrical systems, the flow and the temperature profiles become strongly asymmetric and some thermal slip can occur at the solid-fluid interface, despite the absence of velocity slip. The larger temperature rises and steeper velocity gradients in these cases lead to large reductions in friction, particularly at high pressure and shear rate
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