Combining Near-Field Measurements and Numerical Simulations in the Complete Characterization of Complex Electromagnetic Systems

AbstractA continuum hydrodynamic model has been used to characterize flowing active nematics. The behavior of such a system subjected to a weak steady shear is analyzed. We explore the director structures and flow behaviors of the system in flow-aligning and flow tumbling regimes. Combining asymptotic analysis and numerical simulations, we extend previous studies to give a complete characterization of the steady states for both contractile and extensile particles in flow-aligning and flow-tumbling regimes. Another key prediction of this work is the role of the system size on the steady states of an active nematic system: if the system size is small, the velocity and the director angle files for both flow-tumbling contractile and extensile systems are similar to those of passive nematics; if the system is big, the velocity and the director angle files for flow-aligning contractile systems and tumbling extensile systems are akin to sheared passive cholesterics while they are oscillatory for flow-aligning extensile and tumbling contractile systems.

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Characterization of Reconfigurable LC-Reflectarrays Using Near-Field Measurements

2009 German Microwave Conference ◽

10.1109/gemic.2009.4815846 ◽

2009 ◽

Cited By ~ 2

Author(s):

Sabine Dieter ◽

Alexander Moessinger ◽

Stefan Mueller ◽

Rolf Jakoby ◽

Wolfgang Menzel

Keyword(s):

Near Field ◽

Field Measurements

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Magnetic Dipole Modeling for DC and Low Frequency AC Magnetic Fields in Space Missions

Electromagnetic Compatibility for Space Systems Design - Advances in Computer and Electrical Engineering ◽

10.4018/978-1-5225-5415-8.ch003 ◽

2018 ◽

pp. 71-114

Author(s):

Sotirios Spantideas ◽

Nikolaos Kapsalis

Keyword(s):

Magnetic Fields ◽

Magnetic Dipole ◽

Near Field ◽

Low Frequency ◽

Magnetic Behavior ◽

Field Measurements ◽

Space Missions ◽

Dipole Modeling ◽

Magnetic Cleanliness

In this chapter, modeling methods of static and slowly varying magnetic field emissions that are generated by spacecraft equipment are analyzed and discussed. In particular, specific issues on the established methods for multiple magnetic dipole modeling (MDM) are investigated and validated via near field measurements of well-behaved magnetic sources. Moreover, a software-based calibration technique for measuring facilities, dedicated to magnetic characterization of spacecraft units, is described and implemented on a configuration consisting of 12 sensors. Due to increasingly strict magnetic cleanliness demands, the modeling of units' induced DC magnetic behavior has become a necessary requirement for various space missions. Therefore, a baseline methodology regarding the measurements and modeling of induced magnetic fields is presented. Finally, DC methods are complemented to cover AC magnetic cleanliness requirements for on-ground verification of low-frequency magnetic fields, including AC induced magnetization effects.

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