David Arnold's Research Group

IMG Kickoff Meeting

Event date: 
Fri, 08/22/2014 - 5:00pm to 6:30pm

We will hold an IMG Kickoff meeting on Friday August 22nd in Larsen 310, starting at 1 pm, immediately after our Friday BBQ.  This meeting is mandatory for all IMG personnel.  We will provide an overview of IMG to new students, review lab organization/training, emphasize importance of the wiki, and review safety information.

IMG @ Hilton Head 2014

IMG will present six papers at the upcoming Hilton Head Workshop in June 2014 (www.hh2014.org):

  • N. Garraud and D. P. Arnold, “Characterization of the rotational dynamics of magnetic micro-discs in suspension” (poster)
  • J. Li, V. Tseng, and H. Xie, "Wafer-level fabrication of power inductors in silicon for compact dc-dc converters” (poster)
  • D. Mills, T.-A. Chen, and M. Sheplak, “A MEMS optical moiré shear stress sensor for harsh environment applications” (poster)

  • O. D. Oniku, A. Garraud, W. C. Patterson, and D. P. Arnold, “Development and modeling of a micromagnetic imprinting process” (poster)
  • W. C. Patterson, E. E. Shorman, N. Garraud, and D. P. Arnold, “A magnetic microscope for quantitative mapping of the stray fields from magnetic microstructures” (poster)
  • C. Velez, I. Torres-Díaz, O. D. Oniku, L. Maldonado-Camargo, C. Rinaldi, and D. P. Arnold, “Fabrication of Magnetic Microstructures by In Situ Crosslinking of Magnetically Assembled Nanoparticles” (poster)

Distributed Wireless Power Transmission to Compact Electronic Devices


The maintenance procedures to replace the batteries typically require physical contact or wire connections with the devices, which may be inconvenient, difficult, or costly. Even where batteries can be easily recharged, the ever-growing hunger for portable power presents an important technical challenge. For example, the modern dismounted Warfighter carries a vast array of battery-powered technologies. The logistical burden of monitoring, recharging, and replacing these batteries is overwhelming, and no soldier would willingly go on mission without fully charged batteries. For soldier power systems, there are two main issues: the large number of different electronic devices and the requirement for constant charging for maximum mission readiness.

To address these issues, the project explore the development of an electrodynamic wireless power transmission (EWPT) technology that is capable of wirelessly delivering power to a spatially distributed collection of power receivers over distances of a few centimeters to a few meters. Compared to the more widely studied inductively coupled wireless power transmission schemes, the EWPT technology enables the power receivers to be physically much smaller and with fewer restrictions on their orientation.

In the EWPT system, a transmitting coil is connected to a power source and carries an alternating current. The field generated by the transmitting coil moves a permanent magnet in the receiver through electrodynamic (magnetic) forces and/or torques. The magnet is mounted on a spring and is allowed to oscillate. This motion is then converted into electrical energy using an electrodynamic transduction within the receiver. Even using fairly weak magnetic fields, significant mechanical oscillations can be induced when the receiver magnet is excited near its mechanical resonance (assuming an underdamped mechanical system).

Magnetic Microsystems - What? Where? When? Why? How?

Event date: 
Thu, 08/29/2013 - 5:00pm to 6:00pm

As part of the Fall 2013 ECE seminar series, this Thursday, August 29, Dr. David Arnold will be giving a talk that will highlight his group's development of microfabricated permanent magnets and their application in several functional microsystems.

To set the stage, he will first describe some basic concepts about magnets and physical scaling laws that motivate his group's efforts. He'll then discuss the advancement of two types of permanent magnet materials that has been made by the group; namely, electroplated layers and bonded powders, which overcome certain manufacturing and integration challenges. Finally, He'll showcase how these permanent magnet materials are being used for electromechanical actuators, energy harvesting devices, and generation of high-energy x-rays.

As seats will be limited, all are encouraged to be on time. 

Tailoring Energy Flow in Magnetic Oscillator Arrays

Despite the fact that nonlinearities are inherent in many natural and engineered systems, it is common for engineers to remove, or attempt to remove, all nonlinearity from their designs. Although this simplifies the performance analyses, it also overlooks a wide array of phenomena that could potentially enable fundamental breakthroughs.

The objective of this project is to derive fundamental insights for complex arrays of nonlinearly coupled oscillators, using structures defined as magneto-mechanical lattices. The magneto-mechanical lattices comprise periodic arrays of dynamically interacting magnets, which can be conceptualized as an array of equivalent springs and masses, or alternatively, as a solid composed of artificial macro-atoms. The nonlinear magnetic coupling is to be theoretically tailored to exploit nonlinear energy transfer behaviors, such as reconfiguring bandgaps, energy localization, internal resonances, etc. These nonlinear phenomena are to be experimentally demonstrated and measured by fabricated magneto-mechanical lattices.

IMG Seminar Series: Sub-mm Magnetic Undulators for Photon Generation

Event date: 
Fri, 07/19/2013 - 3:15pm to 4:00pm
This Friday at 11:15 AM, Alexandra Garraud will give a practice talk in preparation for a presentation at the 1st Advanced Superconducting Test Accelerator (ASTA) Users' Meeting at  Fermilab, IL . During this talk, the fabrication, operation and applications of the magnetic undulator with an electron beam will be discussed. All are encouraged to attend. The venue is LAR 234.
The seminar will be followed by the IMG BBQ at 12 PM.