Harnett Lab

Flows can be driven using metallized surfaces in an electric field. This research area is called “induced charge electrokinetics.” It originated in the world of metal colloids, saw some applications in microfluidics in the 90s, and has seen more intense research over the past 10 years. This paper is a good introduction to flows around metal posts in an electric field.
We can measure ICEO effects with video microscopy to track high speed swirling tracer particles. We can also simulate the effects, and one method is to take a commercial computational fluid dynamics (CFD) package to a small size scale that most tutorials don’t cover. Here is our pdf tutorial with links to videos on using ANSYS Fluent to generate microscale flow fields from a given wall velocity, creating images like the fluid velocity vectors shown in the image above.

FirstBuild is helping make a molded plastic diffuser for the Trilife cellular computing project.

The MATLAB file (rainbow colored inset) got CNC milled into a Modulan tool for vacuum forming thanks to Jeremy Turner and Randy Reeves at First Build.
We are looking at PETG for the plastic that will be formed over this mold, because PETG is paintable and can also be laser cut. These diffusers will create the triangular light reflectors that we currently get from folding paper. The paper works great, except it crumples up a lot in transit.

The MATLAB code to create the diffuser surface is… Continue reading “First Build makes an impression”

We continue working with the Welch group at U of L on tracking appliance usage in homes and offices. The goal is for individuals to track their own energy consumption with mobile sensors. Here’s Dr. Welch’s Ph.D. student Anand Kulkarni running an appliance near a copper plane antenna to pick up its electromagnetic field (EMF) signature. Five appliances were classified using a decision tree algorithm. For more, see IEEE Sensors Journal:

There are a lot of low-cost pressure sensors out there but many are made for surface mount, like the one at the left, which is fairly huge for a surface mount part. You are expected to solder the gold leads of this pressure sensor to a printed circuit board (PCB) or adapter. What about when you are still designing your system and have not made a PCB yet? Check out Jaz’s quick way of making the MPXV7007DP fit in a prototyping breadboard using headers that most electronics labs have handy.

Some students have finished things, and others have started new projects.

Jordan Meyer finished her independent study, generating a beautiful image of surface charge density on metal structures using CoventorWare (pictured above), which will plug into Jaz Beharic’s research on flow through metallized membranes. Also last semester, Sherman Dowell and Martin Dombi completed independent studies that provided examples for future students in the ECE412 microcontroller course.

We welcome two new independent study students, Tayce Lassiter and Caleb Sheehan. Tayce is working on impedance sensing in paper and fiber microfluidics, and Caleb, fine-tuning our nanoparticle patterning process. They join Thomas Johnson, who is finishing up his work on mapping and measuring thermal effects of gold nanoparticle coatings.

Last year we said good bye to graduate Dr. Tom Lucas (currently a postdoc at UIC), and now we have a link to his Ph.D. thesis, “Development of a Light-Powered Microstructure: Enhancing Thermal Actuation with Near-Infrared Absorbent Gold Nanoparticles.”

And Dr. Robert Stewart graduated with a Ph.D. from UK in Dr. Jimmy Fox’s group. Robert worked with us on wireless sensor networks for monitoring streams; here’s his thesis: “Decelerating Open Channel Flow Over Gravel: Turbulence Structure & Sensor Development.”