Sunday, 21 August 2016

House Layer, last week (3.-13-8.) and new generation in Ljubljana 20.8.


Here is an update: two weeks ago we have worked on the last week experimenting with bacterias for MFC. Their action was already declining, but we have managed them to run additional tests.



From the beginning of tests, each MFC was measured separately depending on the content of each fuel cell. Final experiments integrated all cells together: connected in series were capable of producing over 1,5 volts.






Current we got from MFC's didn't have enough stamina to run LED. We have also tried Joule thief and charging of a battery as a possible solution for energy harvesting.






At the end of experiments all cells were disposed to the toilet. The opening of bottles released the strong odour.



New tests need more experiments on:
- bigger surface of electrodes
- bigger and shorter protonic bridge or other
- separate three tests with the same amount of meat and bacterias, test with only meat, test with only cultures
- tests with joule thief and battery charging
- possible working on further decomposition as it might represent an important flow of organic matter
- locating of bacteria (microbial cells and organisms from the body) and gas (Co2 ...) in the anaerobic bottles


These first experiments were crucial. Next will start soon in Ljubljana.


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 This weekend meat was not available, but some tests started with old equipment.



At the end of testing MFC's in Kranj, there was a plan to make new fuel cells. One part was for Vinogradsky column and another part was waiting for new tests. Because of illness meat was in the fridge for two weeks. A further study was also kept in the mind: A question of all possible different microbial cultures existing in the process of decomposing of meat (one of the previous post). Meat in the fridge had drained fluids on the bottom of a bag and all over the surface of the meat. In the centre of the meat, it had a fresh appearance. In each bottle around 200 g of meat was laid. At the time it was not important which part was taken - surface or centre. Before putting the methylene blue to the bottles, because of different readings, two bottles were separated, one bottle was extra with just microbic cultures.




A mediator is still working better, but there are already bacterias in the decomposing meat that work mediator free. Question is - are lactobacillus needed (test with just meat in water).



The difference between first and second day is also visible in meat floating on the top. This meat was minced, but it was not blended as in the original tests. Next experiment will be with blended meat.


Anaerobic pots also have one tube each for releasing CO2 and other gases into the air through water container.




Sunday, 31 July 2016

MFC, house Layer, third weekend 31.7.2016


At the end of the third weekend, we (Sara, Benjamin, Z) compared results and the best option in the test of cultures is second or B option of cultures YC-X16


Cultures are mainly Lactobacillus bulgaricus and Streptococcus thermophilus

 

For more precise characteristics like temperature range of culture YC-X16, a technical sheet from the producer CHR Hansen is copied on the post.

A series of graphs is pasted below: y-axis representing current in mV, x-axis are days. As graphs might contain experimental error and measurements in days is made per day and not recalculated by hours (measurements were made mostly in the afternoon or evening from 19 to 21 h) they determine that further experiments will be made with cultures YC-X16 (B)

- cultures  ABY-3 (A) + YC-X16 (B)



cultures ABY-3 (A)
cultures YC-X16 (B) 
different jars



Small deviations are shown, which are minor - more all less measurement we can look as a continuous line.
Results are better with small percentage of culture YC-X16 (B). Additional tests with bigger quantity and even smaller would be nice


Next tests:

- different volumes
- different sizes of electrodes (in diameter) and also in future different materials (test ob bio-charcoal etc.)
- negative tests (meat without cultures YC-X16 and just cultures YC-X16)
- same combinations 3 x test

Tuesday, 26 July 2016

MFC, house Layer, second weekend 26.7.2016

All the measurement are slowly rising or descending. With resistor also current was measured.




And some photos:







Sunday, 17 July 2016

MFC - first weekend


First tests of bioreactor powered on horse meat. With the courtesy of  House Layer in Kranj, we started using a nice place for one-month testing. Before coming to Kranj preparations were mostly getting all materials and equipment needed for tests.  Methylan blue, different measuring pots (Mikro+Polo), Lactobacillus culture (Biotechnical centre Naklo), Agar, agar (food store), Inox rods for electrodes (MDM), carbon (Samson), digital multimeter (IC Elektronik), different plastic containers ... (hardware shop).







Salt bridge initial formula 300 ml of water, 30 ml of salt (NaCl) and 5 g of Agar agar. Later ratio was 10% of salt and 5% of agar agar.





Minced meat was processed in a blender to smaller pieces. Meat 17% (1/2 kg and 2 1/2 of water)

Lactobacillus - bulgaricus and Streptococcus thermophilus



Toner was added to epoxy glue




Preparation of bioreactor was mostly handled by Sara Zupanc and Benjamin Drakslar who were also suggested making additional tests on the different percentage of content of the cultures.






















And the results after the end of the weekend.





Saturday, 9 July 2016

micro fuel cell - preparation

We had a wonderful meeting with Sara and Benjamin in the third biggest brewery in Slovenia - Kranjska pivnica. A short list of ingredients and possible links is added below. Tests will start soon.




mediators:

microbiological cultures
Lactobacillus: 
biotehnični center naklo http://www.bc-naklo.si/index.php?id=215

cheesemaking

agar agar

Tuesday, 12 April 2016

First dissolving experiments

The first experiments with dissolving horse meat, using different acids and catalysts.




Experimental setup


Catalysts used:
  1. Potassium dichromate K₂Cr₂O₇. Solution 1 gram mixed to 50 ml tap water.
  2. Silver sulphate Ag₂SO₄. Solution 1 gram in 50 ml acid
Acids used:
  1.  Sulphuric acid H₂SO₄, 1.8 g/ml
  2. Hydrochloric acid HCl in water solution, 37.5 %
  3. Hydrochloric acid HCl in alcohol solution, 1.25 M
All the experiments were conducted in a similar way. First catalyst solution was poured in the test vessel. On top of this, the acid was added, and finally 5 grams of horse meat in small pieces. The heat of catalyst-acid-meat solution was measured with infrared thermometer.

The test setup also included a peltier element SP1848 attached to the bottom of the test vessel. The element sat on a heat sink that was cooled with a fan. Produced voltage was measured with a multi-meter. The heat conduction path between peltier element and test vessel was reasonably good, but not perfected with silicon paste of such.


 Experiment 1 


Catalyst: K₂Cr₂O₇ solution, unknown amount, maybe 10 ml
Acid: H₂SO₄, 50 ml 

Strong heating to 72 °C was observed after adding acid to catalyst. Adding meat increased to heat slightly to 79 °C, with voltage over Peltier element reaching 250 mV at highest. The meat dissolved completely in very short period of this, perhaps one minute. The color of resulting sludge was very dark red, almost black.

Afterwards, it was considered a mistake to add the meat immediately after acid, as the effect of meat heat was shadowed by heating caused by catalyst-acid reaction.


Experiment 2


Catalyst: K₂Cr₂O₇ solution, 10 ml
Acid: 37.5 % HCl, 50 ml

Compared to previous experiment, very little heating was observed after adding acid to catalyst - only 29 °C was observed. The meat did not seem to dissolve at all, not did it produce heat. The experiment was terminated after waiting for maybe two minutes.

The different between this and the first experiment caused great concern. It was theorized that the acid solution was too old and had somehow lost its potency.

An observation unrelated to the experiment was made. The soda used to neutralize the acid afterwards caused the solution to cool down to 8 °C.


Experiment 3


Catalyst: K₂Cr₂O₇ solution, 10 ml
Acid: HCl 1.25 M, 50 ml

This experiment went similarly to experiment 2. It was (weakly) concluded that hydrochloric acid is not suitable for this project.

After the experiment, some Ag₂SO₄ was added to the solution, just to quickly test if this catalyst could improve the matters. No heat production was observed.


Experiment 4


Catalyst: Ag₂SO₄ solution, 10 ml
Acid: H₂SO₄, 50 ml

No great heat production was observed after adding acid to catalyst. Adding meat caused increase to temperature, with 42 °C observed at highest. Voltage over Peltier element was 42 mV. The meat was visibly dissolving and becoming black on the edges. The experiment was terminated after about 10 minutes, with a large portion of meat still remaining. The color of solution was whitish pink.

This experiment was considered relatively successful since some heat was produced and the reaction did not proceed too fast.

Experiment 5


Catalyst: K₂Cr₂O₇ solution, 10 ml
Acid: H₂SO₄, 50 ml

This was a repeat experiment of experiment 1, in order to replicate the heat production on adding acid, and to measure heat produced by dissolving meat alone.

Adding acid to catalyst caused temperatures above 80 °C. The solution was left to cool until its temperature was at 25 °C before meat was added.

Adding meat resulted in temperature rising to 31°C, with voltage over Peltier element at 34 mV. This went on for maybe 5 minutes, after which temperature dropped somewhat, even though the piece of meat was not completely dissolved.
Note that this experiment was conducted after sunset, when outside air coming in from the window was substantially colder than during the other experiments - maybe 5 °C difference. Also note that the meat was in one 5 gram piece this time.

Conclusions


In light of different between experiment 1 and experiment 5, probably all the combinations did work; the great amount of heat in the first reaction just set unrealistic expectations.

The method used here does not produce very useful amounts of power. The amount of heat generated was below expectations.

It could be useful to  have instruments for voltage and temperature that are connected to computer taking automated longer time series.