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Blog Posts Tagged Microfluidics Module

Tears of Wine and the Marangoni Effect

March 24, 2015

Try pouring some wine into a glass. Don’t drink it yet — this is a scientific experiment. When you hold up your glass, you’ll see what look like teardrops running down the sides. These tears of wine are caused by the Marangoni effect, which describes a mass transfer along the surface of two fluid phases caused by surface tension gradients along the interface between the two phases (for example liquid and vapor).

Dielectrophoretic Separation

January 23, 2015

How can you use an electric field to control the movement of electrically neutral particles? This may sound impossible, but in this blog entry, we will see that the phenomenon of dielectrophoresis (DEP) can do the trick. We will learn how DEP can be applied to particle separation and demonstrate a very easy-to-use biomedical simulation app that is created with the Application Builder and run with COMSOL Server™.

Red Blood Cell Separation from a Flow Channel

January 3, 2014

Before conducting certain blood sample analyses, researchers need to separate the red blood cell particles from the blood plasma. Using lab-on-a-chip (LOC) technology, red blood cell separation can be achieved via magnetophoresis (i.e., motion induced by magnetic fields). Since the magnetic permeability of the particles is different from the blood plasma, their trajectory can be controlled within the flow channel of the LOC device and then separated out from the fluid.

Thermometer Calibration: When Experimentation Falls Short

November 13, 2013

The International Temperature Scale of 1990 (ITS-90) is the industry calibration standard for measuring temperatures throughout the world. The National Physical Laboratory (NPL) works to establish and maintain the ITS-90 through experiments, most notably, thermometer calibration. To better understand and overcome the shortcomings of the experimental process, Jonathan Pearce, at the UK’s National Physics Laboratory, turned to simulation. His results yielded fascinating results about the microscopic behavior of the liquid-solid interface during the freezing process.

Modeling Electroosmotic Flow and the Electrical Double Layer

October 28, 2013

Microfluidic devices are so small that the micropumps and micromixers that control and mix the fluid inside the device cannot involve any moving components. Instead, they must take advantage of electroosmotic flow. Here, I will describe the concept of electroosmosis and the electrical double layer (EDL), and how to model these in COMSOL, walking you through two example models.

Modeling an Accurate Drug Delivery Device

August 22, 2013

There are many different routes through which drugs and other medications can be delivered into a patient’s body during treatment. These include topographical ointments, pills, vaporizers, and injection systems, among others. Many of these drug delivery systems require an enormous amount of precision when it comes to the location, timing, concentration, and amount of the drug to be administered. This is where simulation can be a big help, as it can allow for the modeling of each of these aspects […]

Using a Microfluidic Valve to Separate Charged Particles

July 31, 2013

When you think of a valve, what is the first thing that comes to mind? Electromagnetic waves, or perhaps, Stokes flow separating charged chemicals in a microchannel system? Maybe neither. The truth is, when researchers try to separate small (in the picoliters region), well-defined sample volumes of chemicals, the dispensing accuracy provided by a mechanical regulator probably won’t suffice. An electrokinetic valve, a type of microfluidic valve, on the other hand, provides the perfect solution by giving researchers the flow […]

Microfluidics Model of an Electroosmotic Micromixer

October 31, 2012

When you need to mix something at a very small scale you don’t reach for a teeny-tiny whisk. If you’re working with microscale biochemical applications you’d be more likely to rely on diffusion to mix fluids. With highly ordered laminar flow there is no turbulence involved, thus making diffusion a prime candidate for “getting the job done”. But what if you need to mix larger molecules? Larger molecules mean higher molecular weight, which in turn leads to very long equilibration […]

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