Exhaust gases from an internal combustion engine, alternatively powered by gasoline or by liquefied petroleum gas, were analysed for polynuclear aromatic hydrocarbons. The engine operated a lift truck for the handling of warehouse goods. A combined condensation-filtration apparatus was constructed for sampling of the exhausts. The basic steps of the analytical procedure are summarized here. Sev...

We examine Weyl groups of minimal connected simple groups of finite Morley rank of degenerate type. We show that they are cyclic, and lift isomorphically to subgroups of the ambient group.

Active control of the production choke valve is the recommended solution to prevent casing-heading instability in gas-lifted oil wells. Focus of this work is to find a simple yet robust control structure for stabilization of the system. In order to find suitable control variables, a controllability analysis of the system with different candidate control variables and two alternative manipulated...

Classical extremum seeking control (ESC), when applied to systems with disturbances, can be subject to large deviations during transients caused by abrupt changes in the disturbances. In oil and gas production applications, such deviations can make ESC impractical. This paper presents a simple yet practical extension to the classical gradient-based extremum seeking control to make it robust to ...

Disk galaxies in a cluster of galaxies are moving in hot gas filling the cluster. Generally, they are moving at transonic or supersonic velocities. If ram-pressure stripping is insufficient to destroy the gas disk, the galaxies should be affected by the wind of the surrounding hot gas similar to an airfoil. In this paper, I consider whether the aerodynamic interaction can be strong enough to fo...

Highly oscillatory flow regimes that can occur in gas-lift oil wells have been successfully treated using conventional linear control. However, these control systems rely on downhole pressure measurements which are unreliable or even unavailable in some cases. In this paper we propose a solution based on a high gain observer for the state of the process. The estimates are used to compute the do...