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Biological Waste Treatment
Published in Syed R. Qasim, Wastewater Treatment Plants, 2017
Blowers develop a pressure differential between the inlet and discharge points. They move air or gases under pressure. There are two types of blowers: centrifugal and rotary positive displacement. The centrifugal blowers are commonly used for pressures 50–70 kPa (7–10 psi) and air flows above 15 m3/min (5000 cfm). These blowers have head capacity curves similar to low specific-speed centrifugal pumps (Chapter 9). The operating point is determined by the intersection of the head capacity curve and the system curve. The flow may be adjusted by throttling the inlet. Throttling the outlet of centrifugal blowers is not recommended because these machines will surgefff if throttled close to the shutoff head.
Flans, Pumps, and Steam Turbines
Published in V. Canapathx, Steam Plant Calculations Manual, 2017
The operating point is the intersection of the combined performance curve with the system resistance curve. Figure 5.6 explains this. Head and flow are shown as percentages [2]. ABC is the H versus q curve for a single pump, DEF is the H versus q curve for two such pumps in series, and AGH is the H versus q curve for two such pumps in parallel. To obtain the curve DEF, we add the heads at a given flow. For example, at q = 100%, H with one pump is 100%, and with two pumps H will be 200%. Similarly, AGH is obtained by adding flows at a given head. At H = 100, q for two pumps will be 200%.
Nonlinear optimal control for the inertia wheel inverted pendulum
Published in Cyber-Physical Systems, 2020
G. Rigatos, M. Abbaszadeh, M.A Hamida
In this article, a novel nonlinear optimal control method is developed for the inertia wheel inverted pendulum while the global stability properties of the control scheme are also proven. First, the state-space model of the pendulum is subjected to approximate linearisation around a temporary operating point which is recomputed at each iteration of the control algorithm [31,32]. This operating point is defined by the present value of the system’s state vector and by the last value of the control inputs vector that was applied on it. The linearisation procedure relies on first-order Taylor series expansion and on the computation of the system’s Jacobian matrices [33–36]. The modelling error, which is due to the truncation of higher-order terms in the Taylor series expansion is considered to be a perturbation which is asymptotically compensated by the robustness of the control loop. For the approximately linearised model of the pendulum, a stabilising H-infinity feedback controller is designed.