Active Galactic Nuclei are fueled from material (gas or stars) that are in general far away from the gravitational influence of the central black hole, the engine thought to be responsible for their activity. The required material has a lot of angular momentum, that is a priori quite difficult to evacuate. The various dynamical mechanisms that may play a role in this game are reviewed, includin...

Concept Outline 51.1 Animals employ a digestive system to prepare food for assimilation by cells. Types of Digestive Systems. Some invertebrates have a gastrovascular cavity, but vertebrates have a digestive tract that chemically digests and absorbs the food. Vertebrate Digestive Systems. The different regions of the gastrointestinal tract are adapted for different functions. The Mouth and Teet...

This paper deals air to fuel ratio control of a spark ignition engine, whose pollutant is a major cause of air pollution. A direct adaptive control using Gaussian neural networks is developed to compensate transient fueling dynamics and measurement error in mass air flow rate into the cylinder. The transient fueling compensation method is coupled with a dynamic sliding mode control technique th...

Peaked density profiles may not only improve confinement properties, but also give the additional benefits of increased fusion production and ignition margin in BPX, as shown in Fig. 8.1. The ability to control density profiles in the core and scrape-off regions is governed by a number of both physics and operational considerations that make it difficult to specify optimized fueling systems. Fo...

Modern spark ignited (SI) internal combustion engines maintain their air-to-fuel ratio (AFR) at a desired level to maximize the three-way catalyst conversion efficiency and durability. However, maintaining the engine AFR during its transient operation is quite challenging due to rapid changes of driver demand or engine throttle. Conventional transient AFR control is based upon the inverse dynam...

Recent observations have indicated that a large fraction of the low to intermediate luminosity AGN population lives in disk-dominated hosts, while the more luminous quasars live in bulge-dominated hosts (that may or may not be major merger remnants), in conflict with some previous model predictions. We therefore build and compare a semi-empirical model for AGN fueling which accounts for both me...