I'm presenting a sensor array that's deployed in the sea at various depths, and which measures various aspects of the marine environment. Conductivity, Temperature and Depth (actually pressure) are the most basic physical values used in marine research, but the CTD that I have in my hands is configured with a few more sensors.
Check out the sequel in which I talk about related and quite interesting topics (including CTD): https://www.youtube.com/watch?v=oK0bqY7JBOc

I am presenting a rain collector/sampler and sensor which has a dual function... and is not microfabricated. It's used for scientific research on rainwater composition and air particulates of coastal areas.

I show fluorescence in aqueous solutions of rhodamine B and fluorescein. Spoiler alert: the red laser does nothing.

Some tips and tricks to use if you want to improve your fidget spinner, not all entirely obvious. I had little interest in these gadgets until my wife bought one for my son. As a good dad I decided to participate in his new interest.

We published an article on this 3D printed microreactor at http://pubs.rsc.org/en/content/articlehtml/2017/re/c7re00015d

In this video we present a 3D printed polypropylene microreactor with an integrated stirring bar and nano-electrospray needle.

The nano-ESI needle is the ion source of our microreactor, and is used to couple it directly to a mass spectrometer. The microreactor is used to analyse chemical reactions with the mass spectrometer. The reaction is analysed as it happens.
We used polypropylene to 3D print the microreactor, because polypropylene is a very refractory polymer in the sense that it is neither affected by strong acids or alkaline solutions, nor by the great majority of solvents used in chemical synthesis.

This is the first 3D printed microreactor with an integrated ion source. It is also the first 3D printed microreactor with an integrated stir bar. These enable us to monitor the chemical reactions in real time.

The link to the article is http://pubs.rsc.org/en/content/articlelanding/2017/re/c7re00015d#!divAbstract

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We have inserted a red LED into liquid nitrogen (which means, we decreased its temperature to -195 °C) while observing its emission spectrum with an optical spectrometer. We noticed that the peak of the spectrum moved towards the shorter wavelengths.
This is actually an expected result, because with decreased temperature the inter-atomic distance in the crystal lattice of the semiconductor decreases. One consequence of such distance decrease is an increase of the semiconductor's band-gap, which then causes the emitted photons to have a higher energy.

We did a few more experiments with our new toy - a mini spectrometer. We measured the emission spectra of red, green, and purple (405 nm) lasers and LEDs. We also measured the fluorescence spectrum of a photostructurable acrylic resin.

Playing with a mini spectrometer: we were measuring the reflection and fluorescence spectra of four different fluorescent Post-It notes.

These are silicate garden (also known as chemical garden) experiments with potassium silicate aqueous solutions as media and nickel, cobalt and ferric (Fe(III)) chlorides as seeds.
Nickel and Fe(III) silicate "plants" were grown in a 10% solution, whereas cobalt chloride was dropped in a 15% solution of potassium silicate.

Of the three transition metal chlorides, ferric chloride produces the most dramatic, chaotic and unpredictable results.
With cobalt chloride, the growth is rather fast - I had to slow down the video by a factor of 2 to make it pleasant to watch.

In this video I am showing a simple microfluidic set-up that my colleagues and I have built to test the capillaries, nuts and ferrules for leaks together with a full-glass microreactor microfluidic chip. For fun, we decided to pump water coloured with blue and yellow food colorants, and "see Mr. Reynolds in action". The result was so nice that I will probably use it during one of my lectures on microfabricated fluidic devices early next year.

What makes this so interesting

Actually, this is a very well known phenomenon happening at low Reynolds numbers, assuming a high enough flow of the fluids and low enough diffusion coefficient D. This phenomenon is discussed and illustrated in MEMS and microfluidics textbooks very often. But now you have the opportunity to actually see it with your own eyes in real time, not just a static image of the phenomenon (though, because of the extremely high stability of the set-up, the microscope image seems static).

What is the scientific background

Without going too much into detail, it is important to know that liquids, when flowing through microscopic vessels (or if the liquid is extremely viscous, then larger vessels would show the same effect) tend to flow in a laminar rather than turbulent or chaotic way. Fewer or no vortices, an ordered, highly predictable flow of fluid with velocity vectors parallel to the surface of the vessels. The Reynolds number Re determines how turbulent the flow will be - check out the Wikipedia page for Reynolds number for further info. In brief, the Reynolds number can be viewed as the ratio of inertial forces and viscous forces, and if this number is very high (higher than a few thousand), you have turbulent flow.

Another dimensionless number important for the description of the phenomenon in the video, is the Péclet number: this number determines how soon the two liquids, flowing side by side, will mix due to diffusion. The Péclet number is the ratio of advective and diffusive transports - to simplify, you can just remember that the velocity of the fluid is in the nominator, while the diffusion coefficient is in the denominator. The larger this number is, the longer the stretch where the liquids co-flow without mixing.

A bit of (engineering) math

The width of the channels in the microreactor is about a hundred µm or a bit more. Maybe up to 200 µm (just by eyeballing from the microscope image). The vessel's hydraulic diameter is different from the width that we see with the optical microscope - it depends on the shape of the cross section. As we don't know the exact cross section of these channels, we'll make the approximation that the hydraulic diameter it's close to about 100 µm. You will see soon why this approximation is good enough.
The speed of the fluid, again by eyeballing the coloured water front's movement in the channel, seems to be less than 1 cm/s for a flow rate of 10 µL/min (combined flow rate of 20 µL/min). And the liquid is water with food colorant. For water, the kinematic viscosity at room temperature is about 10-6 m2/s.
If we put these values into the formula for Reynold's number, we obtain
Re = 1
that is, the Reynold's number for this system is one! This is three orders of magnitude smaller than the smallest value for Re for which laminar flow is certain to occur - namely, a few thousand. The Re number was even smaller when I turned the flow rate from 10 µL/min to 0.2 µL/min.

Learn a simple but useful and rather common cleanroom procedure - making smaller chip from full wafers by cleaving.

Our journal article "Laser Additive Manufacturing of Stainless Steel Micro Fuel Cells" is available at http://www.sciencedirect.com/science/article/pii/S0378775314013615

Starting from a used Pasteur pipette, you can fairly easily make a small test tube.

Learn about the behavior of these three pH indicators. The alkaline solution is diluted drain cleaner - NaOH. The acidic solution is citric acid dissolved in warm water.

Doctoral thesis defence - the topic is microfabrication of micro fuel cells - held on the 9th of May 2014. The opponent was Prof. CJ Kim.

The scientific articles discussed during this thesis defence were:

"Silicon nanograss as micro fuel cell gas diffusion layer"
http://digital-library.theiet.org/content/journals/10.1049/mnl.2010.0122

"Integration of carbon felt gas diffusion layers in silicon micro fuel cells"
http://iopscience.iop.org/0960-1317/22/9/094006

"Bulk-Aluminum Microfabrication for Micro Fuel Cells"
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6575144

"Picosecond laser ablation for silicon micro fuel cell fabrication"
http://iopscience.iop.org/0960-1317/23/5/055021

Near the end of my defence I am referring to formulas for scaling of pressure vessels. The formulas are found at: http://en.wikipedia.org/wiki/Pressure_vessel#Scaling

Part of a series on microfluidics.

Black silicon AKA silicon nanograss is a surface modification of silicon, obtained by subjecting the silicon wafer to SF6 plasma in passivating conditions. Black silicon is composed of a dense "forest" of silicon needles a few hundred nanometers in diameter at the base, and a couple micrometer high. Black silicon traps visible light very efficiently.

With a few drops of hydrogen peroxide we show the existence of a very thin (1 nm) layer of platinum deposited on a piece of silicon wafer using a technology called atomic layer deposition (ALD).

This was shortly before I finished my PhD in materials science - micro -and nanotechnologies.