We analyze data from two FAST satellite passes in the vicinity of auroral surges (as seen in the VIS auroral imager on the Polar satellite) to study the large scale ionospheric electrodynamics of the surge, focusing in particular on the configuration of field-aligned and ionospheric currents. While most previous ground and satellite observations have found the surge to be a region of predominan...

With liberalization of European market, many high head power plants in Switzerland increase their potential generation to remain competitive. The existing surge tanks have to be modified to keep the flow management constant. A relevant way to limit the time of mass oscillation is to increase head losses at the entrance of a surge tank with an orifice. This study focuses on the influencing param...

The paper proposes to establish a program for characterizing surge events according to the capability of a surge event to deliver a surge current through the power system in end-user facilities. This characterization would replace the conventional and by now misleading monitoring of surge voltages. The new approach will use a current transducer including a silicon-avalanche diode with the lowes...

This tutorial explains the surge phenomenon as well as the precursors of surge and the damage that surge can cause to the equipment. Then, methods to keep the compressor system from surge, i.e., modern surge control systems, are discussed. This includes the necessary instruments, algorithms used, as well as the piping layout required. Sizing considerations for valves and other system components...

An experimental study was performed to identify the surge inception dynamics and to demonstrate an active surge control on a 600 HP class Allison 250-C30 gas turbine engine. Throttling orifices inserted between the compressor and the combustor were used to move the steady state operating line toward the surge line. The compressor was then adjustably throttled into surge using water injection do...

Based on the proliferation of surge-protective devices in low-voltage end-user installations, the paper draws attention to the need for changing focus from surge voltage measurements to surge current measurements. One proposed approach was to develop a simple transducer measuring the surge current that would be drawn in an SPD with low clamping voltage connected to the circuit to be monitored. ...

Human chorionic gonadotropin (hCG) has been used as a surrogate for the mid-cycle LH surge for several decades. Due to structural and biological similarities with LH, hCG binds to and activates the same receptor - the LH/hCG receptor. However, despite the fact that hCG effectively secures final oocyte maturation and ovulation, its use as a surrogate for LH has got several drawbacks - first and ...

BACKGROUND The association of preawake (difference between pre- and postwaking blood pressure (BP)) and sleep-through surge (difference between sleeping nadir and postwaking BP) with cardiovascular events is unclear. Examination of factors associated with surge may provide novel insights. We examined the association of race, which associates with nocturnal dipping, and plasma renin activity (PR...

To avoid co-surge the mass flows should be kept balanced. Still co-surge can occur when operating close to the surge line due to disturbances between the two mass flows. In that case the control system needs to detect the co-surge oscillation and take proper actions. The simulation model is used to evaluate detection and control algorithms, which are then tested in vehicle. −0.25 0 0.25 0.5 0.7...