17,743 research outputs found
Conquest of the ghost pyramid of the superstring
We give a new Becchi-Rouet-Stora-Tyutin operator for the superstring. It
implies a quadratic gauge-fixed action, and a new gauge-invariant action with
first-class constraints. The infinite pyramid of spinor ghosts appears in a
simple way through ghost gamma matrices.Comment: 30 pages, 1 figure, Late
Combined radiation, convection, and conduction for a system with a partially transmitting wall
The net radiation method is developed for systems having both opaque and partially transparent walls. Heat convection is present at the surfaces and heat conduction through the windows is taken into account. Specific equations are derived for a window between two parallel plates, where one plate is at an elevated temperature typical of what would be encountered in an electric furnace, and the other plate is being cooled. A two-band model is used with cutoff wavelengths typical of glass or quartz. Numerical results are obtained for the window temperature and the heat flow through the window. The effect on these quantities of various plate temperatures and emissivities is shown
Liquid jet pumped by rising gas bubbles
A two-phase mathematical model is proposed for calculating the induced turbulent vertical liquid flow. Bubbles provide a large buoyancy force and the associated drag on the liquid moves the liquid upward. The liquid pumped upward consists of the bubble wakes and the liquid brought into the jet region by turbulent entrainment. The expansion of the gas bubbles as they rise through the liquid is taken into account. The continuity and momentum equations are solved numerically for an axisymmetric air jet submerged in water. Water pumping rates are obtained as a function of air flow rate and depth of submergence. Comparisons are made with limited experimental information in the literature
- …