King's Island Amusement Park

Figure 1. Group shot midway through the day. (From Left to
        Right: Naveed, David, Lindsay, Pablo, Me, Stella, Casey, Stefani,

        Josh, Harrison)

On Friday night we left for Cincinnati for the weekend. As part of the REU program we received tickets for a day at the King's Island amusement park near Cincinnati. When we arrived in Cincinnati we ate dinner at a shopping mall-movie theater combination. We then checked out the water and the purple people bridge. When we got to the hotel we watched some winning Gamecock Baseball vs Arkansas and played cards. A few of us went to Walmart late that night where Pablo bought himself and Stella fanny packs. The next day was bright and sunny, which meant the shortest line was right as we arrived there. We waited for about 30 minutes to ride the Diamondback (Figure 2), a mile long roller coaster with 3 massive drops.

Figure 2. The first hill of the Diamondback Roller-coaster at King's Island.

After that, things became less exciting as we waited in line for 30 minutes for an indoor roller coaster only to have it break down before we could ride it. Every coaster line after that was at least an hour long. After an all-you-can-eat buffet, we met up with more of the REU students (Figure 1) and rode a few more roller-coasters and then checked out the waterpark. Compared to Noah's Ark it was very tiny. We went down a few regular slides and tried boogey-boarding, which I was unable to do. Half of our group left and I met up with the rest to ride a couple more roller-coasters before closing. We rode the Beast after dark, which is the world's longest wooden roller-coaster. It was quite thrilling to plunge into complete darkness and be whipped around random turns. The Beast lasted over 4 minutes. Then we walked past the Eiffel Tower on the way out (Figure 3).

Figure 3. In front of the Eiffel Tower near the park gate. 

Legends Game and Gun Show

Last Tuesday we went as a group to an classic showdown between the Lexington Legends and the West Virginia Power. These two Single A baseball teams squared off in front of the nearly sell-out crowd of 237 people and played their hearts out. The game started off in the first inning with the announcement of 35 cent hot dogs. Many people fled their comfy stadium seats for the cheap wieners. I only had two because nickels were in high demand. I ended up giving my nickel to my roommate Josh so he could buy his third hotdog. Until the fifth inning, very little happened. Some kids spun around bats and raced. And a few runs may have been scored. The sun was also shining just right, making the ballpark the perfect place for a nap. But at the start of the fifth inning it was announced: "One Dollar Beer! Get it while it's cold!". This caused the majority of the other REU students and most of the crowd to once again leave their seats and open their wallets. Many came back holding three or even four dixie cups of the clear warm light yellow liquid. Somehow a cup ended up in front of me. It contained a mixture of beer, dippin dots, and pop. Needless to say, I didn't try any. The next bit of excitement was when the McDonald's girls started throwing things out to the crowd. I'll let you guess what they were passing out:

Figure 1. What they should have been throwing to the fans.

 T-shirts?. . .  No. . . . Baseballs?. . .  No . . . Hotdogs? . . . No . . . Souvenirs? . . .  I guess? . . . Lumps of coal?. . . You betcha! One of the lumps of coal sponsored by Friends of Coal landed in the middle of our group. There were many cries of "wtf?" and "what is that? I don't remember who took the coal home, or if it was just left in the bleachers. The final exciting moment in the game occurred when two kids squared off with inflatable ponies and raced. The ponies were very large compared to the boys and the ponies had no legs, which meant the boys had to bounce along, rather than run with it between their legs. It was rather comical when one of the boys face-planted because he was trying too hard to go fast. He ended up winning, but kept falling off his pony. In the sixth inning two kids took over for the announcer and believe it or not did a better job announcing. The seventh inning proved too much and we headed back to the dorms. It was such an intense match-up that none of us can recall the score or who won. 

Figure 2. What they were actually throwing to fans at the Legends game.

On Saturday we went to the Lexington gun show. I saw some pretty cool guns, including a number of AK-47s and some pretty cool tactical firearms. Unfortunately, we weren't allowed to take pictures at the gun show, so I don't have any cool shots. In addition to guns, they had a lot of knives. I checked out some pretty nifty switch blades, which were only $20. I also saw an authentic Nazi police helmet and some Nazi knives. If I knew more about gun and knife prices, I may have invested in something, but I wasn't going to take a gamble. The only thing that tempted me briefly was a stun flashlight. It's a high-powered LED flashlight with a stun tip. Apparently it takes over two hours for the effects to wear off. It was only $45 and I could use a new flashlight, but I decided it wasn't worth it. We also saw some very interesting people there, including one girl who was napping face-down on a rolling dolly inside one of the booths. It took us quite a while to notice her. That night we had fun playing sardines and capture the flag with some electrical engineering REU students, which capped off a pretty fun weekend.

Figure 3. AK-47s. Similar to some displays at the gun show. 

Image Sources:


Figure 1: http://lexington.milbstore.com/store_contents.cfm?store_id=19&dept_id=-1&product_id=7981

Figure 2: http://geraldmceachern.blogspot.com/2011/05/energy-you-put-in-is-energy-you-get-out.html

Figure 3: http://www.wired.com/magazine/2010/11/ff_ak47/

Testing Calorimeters

In order to design and create a working device, I must test a number of different variables that could affect its performance. My first series of tests works with the same template pictured in my previous post. I am currently testing both the reactiveness of the Heraus thermistor ink with the LTCC tape and the effectiveness of different coverings for the thermistor with 32 chips. To test the reactiveness of the thermistor ink, I pre-fired half of the samples before applying the ink to see whether it works better than co-firing the ink with the LTCC. After applying the ink, I applied an additional layer of LTCC tape to four pre-fired and four co-fired chips (Figure 1). In addition, I added an LTCC paste to four of each, and have yet to print layers of two different types of glass on the remaining eight chips of each type. 

Figure 1. LTCC Calorimeter covered with additional tape layer. 

Although this test seems to be relatively straight-forward test of two variables, I have already encountered my share of problems. During the initial electrode screen printing phase, I must have dropped a hair in the screen because a number of my samples have a hairline gap in the printed wires, which renders them useless. I was able to touch-up paint the ones that I didn't already cover, but the majority of the LTCC tape covered sample (Figure 1) are useless. In addition, I had an issue with the furnace over the weekend that ruined at least one chip and required me to re-fire many others. Hopefully by the end of tomorrow I will have at least one working chip for each condition. 

Testing at least one chip for each condition will give me an idea of what techniques work well, but I will have to repeat this experiment to confirm my findings. At the very least, I have a lot more experience working with LTCC and the screen printer and I should be able to avoid any printing or furnace errors next time around. 

Figure 2. New wiring layouts for two chips. Thermistors and
holes are in black. Wires are in gold. LTCC ceramic is blue. 

I am also working on ordering new thermistor and electrode layouts (Figure 2). If all goes well, I will be printing with the new layouts next week. Ideally, I should be able to do all of my testing with these new layouts, which should work very well for my purposes. When I designed these new layouts, I made the wire width thicker to reduce printing errors, I added a third channel so we can have a control and two experimental sensors on each chip, I added three thermistor layouts so we can test and optimize thermistor patterns, and I added circular leads with holes (instead of rectangular as seen in figure 1) for easy soldering. 

After I test the different thermistor coverings and whether pre-firing the ceramic helps prevent the LTCC and thermistors from reacting, I will begin testing wells. Right now, to test the thermistors, I can  drop reactants right onto the ceramic to measure the heat of an exothermic reaction. Once I have established that the thermistors are working properly and I can accurately record temperature, I will build wells on top of thermistors. The bottom of these wells will be coated with a substrate, likely gold, onto which antibodies will be secured. These antibodies are the start of a long chain that will be assembled on the gold surface to catch proteins and initiate a chain polymerization reaction, that gives off a heat profile from which we can determine the concentration of that specific protein. 

I am a long ways off from actually working with the proteins and the chemical reactions to surface coat the wells. I plan on continuing my work with the sensors and then doing some basic experiments with the wells before surface coating them. I definitely have enough to keep me busy for the rest of the summer. 

LTCC Ceramic Calorimeter

Although LTCC ceramic can be used for a huge number of applications, one promising application is using ceramic to fabricate calorimeter devices for biodetection. The focus of my research this summer is to create such a calorimeter. Because circuitry can be screen printed on LTCC ceramic, the material lends itself well to calorimeter fabrication. This has already been demonstrated by Missal in [1]. He created a differential scanning calorimeter using LTCC materials.The importance of using LTCC materials over conventional materials is that LTCC can be used to fabricate very small devices. Large analyzers can be redesigned and produced using LTCC tape.

The goal of my summer research project is to produce a simple cost-effective biodetector using a simple heat sensor. Many biodetectors use color or size to differentiate and measure molecules. The alternative approach I will be using is to measure an exothermic reaction with a heat sensor. The temperature data from this sensor can hopefully used to accurately measure the concentration of the reactants.

Figure 1. Exposed LTCC temperature sensor.

The fundamental component used in my heat sensor is a thermistor. A thermistor is a resistor with extreme temperature sensitivity. A very small change in temperature will result in a massive change in resistance. Because I am using a printable thermistor material, I can experiment with different shapes to optimize sensitivity. Currently I am using a design that was developed by my mentor Dr. Rich Eitel (Figure 1), but I am working on a new design that will allow me to test multiple thermistors using the same screen (Figure 2). In order to screen print, a new screen must be made for each design. In Figure 1, the model uses two screens, one for the electrodes and one for the thermistor material. Screen printing works by squeezing a small amount of ink through a tight mesh. 

Figure 2.  Draft of new screen designs. Each design is for
one 3"x3" sheet of LTCC ceramic and will make 2 chips.

I have already run one test on the current model and I currently fabricating several more chips. I tested the chip in ice water to get a baseline for noise. From the data analysis, I determined that I should be able to measure temperature fluctuations as low as .01 degrees Celsius with the thermistors. My new screen designs are still in progress, Figure 2 is only my first draft, and I plan on making several improvements before we make the screens. Not only will the new design allow for testing three resistors with the same screen, it will also have three sensors instead of two. I am also working on designs for wells to contain reactions and lay over the thermistors (Figure 3). The final device will have microfluidic channels leading into wells on top of each thermistor.

Figure 3. Draft of channel and well design. 

References

[1]    W. Missal, J. Kita, E. Wappler. Miniaturized Ceramic Differential Scanning Calorimeter with Integrated oven and Crucible in LTCC Technology. Sens. Actuators A: Phys., 172 (2011), pp. 21-26

Balloon Race and Bourbon Tour

6-10-2012

Figure 1. Group Shot with balloons in background
(L-R Kiva, Harrison, NK, Pablo, Thao,
Ben, Sarah, Josh, Alex, Stella, Sarah's Friend)

On Friday night we went to the hot-air balloon race in Danville Kentucky. It was an interesting concept. We arrived at the Danville airport and bought some pulled pork and pop, then watched some clowns and old-fashioned bicyclists before the main event began. There was also a tethered hot-air balloon that was available for free rides about 20 feet high (Figure 2). The line was much too long, so none of us tried. Once the race began, we saw a few balloons miles away lift off and begin their journey towards the airport. The balloons were pretty well spread out (Figure 1). A couple hours later only one balloon had made it. The object of the race was not who could get to the airport first, but who could drop a bean-bag closest to a large X painted on the ground. We watched a couple other balloons try to get close, but they seemed to be having technical difficulties maneuvering the balloon. In the meantime, we took some goofy pictures and had a good time spotting new balloons. 

Figure 2. Holding the tethered balloon.

Saturday morning we went to the Woodford Reserve Bourbon Distillery. It is a national historic landmark and was pretty fun to tour. After a small admission fee, we had to wait around for the next tour, which gave us time to explore the gift shop and read a bit of history of bourbon. Once the tour began we placed radios around our necks and earbuds in our ears. It was neat how we were able to hear the tour guide quite well the entire time. After taking a bus ride 200 feet down the driveway, we toured the fermentation vats. These giant vats were over 10 feet in diameter and 15 feet high. They contained fermenting mash and were exposed to the air. The mash was bubbling like crazy and releasing carbon dioxide. After fermentation, the mash is moved into the stills. It is distilled three separate times, which purifies it and gives it a very large alcohol content, which must be diluted. After dilution the white whisky is placed into charred barrels to age for seven to nine years. The aging warehouse was absolutely gigantic and contained thousands of barrels. Our tour guide reminded us that Woodford Reserve is a "tiny" distillery. Jack Daniels produces many times more. After aging, the bourbon is bottled and ready for sale. Compared to the aging warehouse, the bottling facility was tiny. The last part of the tour was complimentary shot glasses (Figure 3) with samples and bourbon balls for those of us under 21.

Figure 3. Souvenir from the Woodford Reserve Distillary.  

Introduction to LTCC technology

6-4-2012

Last week was my first week in Dr. Eitel's lab. I began my research project, which is to design a ceramic chip with microfluidic channels for biodetection. The material used to make these ceramic chips is Heraus Herlock Low Temperature Co-fired Ceramic tape (LTCC tape). LTCC tape can be purchased in bulk and allows for easy assembly of small ceramic devices. The tape can be cut into a variety of shapes and layered to form a 3-D object. In Dr. Eitel's lab we use a laser cutter, which was originally designed to engrave trophies, to shape the ceramic tape. After cutting out all the required pieces for a given object, and perhaps printing circuits or otherwise modifying them, the pieces are assembled on a form and pressed in a uniaxial press. The form used to assemble LTCC ceramic tape has holes in the corners that line up with holes cut into each piece. This allows for shapes on one layer that line up perfectly with the tape below. After pressing the tape together (the tape is not actually tacky, so it requires pressure to stick), the layered pieces are trimmed, vacuum-sealed, and placed in an isostatic press. The isostatic press allows for uniform compression around the ceramic and the vacuum bags protect the ceramic from the oil used in the isostatic press. The isostatic press contains an oil solution, which can be pressurized to thousands of pounds per square inch. When removed from the isostatic press, the ceramic is completely devoid of air between layers and is ready for firing. After being fired in a ceramic oven for about 12 hours, the LTCC ceramic product is ready to use.

The remarkable thing about Herlock LTCC ceramics is the lack of shrinkage in the lateral directions. Normal ceramic shrinks in all directions and is typically created from a uniform mixture. The Herlock LTCC is layered with different ceramic powders, each of which has a unique sintering point. One layer will shrink, but because it is attached to a layer that is not also sintering, it will be limited to vertical shrinkage. Then the next layer will be limited to vertical shrinkage by the previous layer, and so on. Therefore, with Herlock LTCC there is a large loss of thickness, but virtually no loss in length or width. This allows for the creation of objects to scale without having to factor in the shrinkage parameters.

Trip to Red River Gorge

6-2-2012

Figure 1.  One-way tunnel view from the back seat

Today I went to the Red River Gorge with my roommate Josh, Harrison, Casey, and Pablo. We had to drive through an awesome one way tunnel to get into the park (Figure 1). After exiting the tunnel we realized that the GPS was no longer functional, so we stopped at Red River Gorgeous for directions. Instead of driving through the tunnel, we needed to drive on top of the tunnel. The drive from Tunnel Road to Tunnel Ridge Road took about 20 minutes. Finally we reached our destination and had a wonderful hike to Courthouse Rock.

Figure 2. The bat cave

Figure 3. Climbing Courthouse Rock

At Courthouse Rock, we did some off-trail exploring and found a nice cave with a few bats (Figure 2). I tried climbing the rock (Figure 3). We also found a lot of blueberries which we enjoyed munching on. The red-river gorge was a pleasant experience and I look forward to exploring more of the park in the future.