Just a thought. There was an announcement on the MFMP about a group that claimed to demonstrate excess heat using alloys of palladium and rhodium. They stressed that they only obtained results with an alloy. Perhaps Lithium and Nickel are the complementary materials needed. However just mixing the two won't make an alloy. Perhaps you can electroplate your nickel heater wire using a mixture of nickel and lithium in the 10:1 ratio and see what effect that has.
GlowFish
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Posts by GlowFish
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I assume the PCE830 calculates the real power from its own measurements. Even if the coil does change resistance or inductance, it doesn't matter as long as the PCE830 measures true RMS power, the feedback loop will compensate accordingly.
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What are the COP estimates based on? Difference in temperature at a fixed power level? Temperature at a certain power level surely can be influenced by a number of factors such as tube pressure, gas type, local ambient, cooling drafts etc.
EDIT: Apologies, I see this point has already been raised earlier in the thread.
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If the Nickel is used to create atomic hydrogen and this hydrogen permeates the Nickel lattice, then wouldn't having the Lithium embedded in this lattice increase the chances of an interaction? This is assuming the reaction is a of a Proton-Lithium type.
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A thought. If the Nickel grain size is important then ignore this. However, if the nickel grain size does not play too much of a role then why not "mix" the Nickel and Lithium together onto a surface using electroplating? Perhaps you can coat an iron pin with a Lithium - Nickel combination by dissolving the Nickel and Lithium in an acid solution and electroplate the pin using this solution. The coated pin and the LiAlH4 can be heated together as normal in the tube.
(EDIT) Clarified text a bit
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2. To achieve the state I am looking for, it is REQUIRED to have pulsed power, as the constant EM field produced by a constant voltage and current will not do to achive loading of Ni (that is my presumption what is taking place)
I am not sure what effect EM fields would have but perhaps the pulsed power that you applied has the effect of producing heat related pressure pulses in the gas and this was the driving force that enabled better loading to take place?
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I would imagine if the pressure drop is due to a chemical reaction then it is not a reversible one as the pressure would go up again when the power is reduced to about 25W. The blue graph is CCM? Nothing significant that I can see there.
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If changes in pressure are required, couldn't mechanical means be used like a piston of some sort instead of reliance on chemical reactions?
A little closer look seems to show that LiAlH4 is ionic so it is a lithium salt after all.
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Would the need for Lithium containment mean having a metal fuel container (such as steel) make a bit more sense? If you need the lithium to react with alumina (for whatever reason) then you can add a little alumina powder to the fuel.
(EDIT) A thought. If you just need a higher lithium concentration in the fuel, can't you use some sort of Lithium salt?
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@Ecco A question. Even if the lithium reacted with the alumina, why should that cause a massive pressure drop? They are both solid powders, I would only expect a massive pressure changes if for example gasses reacted to form a liquid or solid.
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The pressure dropped really fast, into under pressure. The pressure transceiver is only working for over pressure, so it went out of range. The true pressure is thus not known. Infact, the low pressure broke the transceiver.
A question. Are you sure the "pressure drop" wasn't due to the transceiver breaking at the pressure peak then reporting false measurements afterwards, for instance if the sensor diaphragm ruptured?
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that sounds complicated. What about this? Methane (CH4) can be thermally dissociated into C + 2H2
Also a little off topic but why not use Methanol? it is a liquid rather than a gas and may be easier to handle. It apparently decomposes into hydrogen and carbon dioxide given the right conditions.
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I may be mistaken but I do recall a report a while back (I think it was mentioned on the MFMP site) of a group that was attempting to set up an experiment with inductive heating. They used a "coil" made from copper tubing and they passed water through it for cooling. I am not sure whether anything came of it.
Problem with inductive heating is that you then need a high power oscillator with resonant point tracking to drive the coil. Typically you need a frequencies in the kHz range to get effective heating as you basically are using a air-core transformer. I am not sure how much inductive heating you will actually get in a nickel powder with just the mains supply.
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Looks great. Just some quick questions. Does the DAQ have its own input filter? Perhaps add small 10n cap and maybe a load resistor across the output of the Op-amps U1 and U2 and from the 7.5V to GND at the pins of the op-amps (U1, U2 and U3) to decouple HF noise especially if the DAQ is going to be at the end of a lengthy cable. The 7.5V reference is generated by a linear adjustable regulator which is source only so your 7.5V reference "sink" impedance is basically only your feedback network. Perhaps add a small 0.1uF ceramic in parallel with your output electrolytic to sink HF noise as C6 might have fairly high ESR. I also noticed that the LM317 regulator will only regulate properly if it has a minimum load of about 10mA. May I suggest R2 = 560 ohm and R1 = 110 ohm?
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Possibly the Nickel could form oxides during the baking process however it seems that Nickel apparently only starts oxidizing at about 400 deg C. Baking Nickel oxide in a hydrogen environment apparently reduces it back to Nickel anyway according to Wikipedia.
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Ok, so from the circuit diagram you are using an low side switched IGBT with PWM to control the power to your heater. You also seem to be using a stepwise hysteresis control in your code?
Your code looks almost like a Fuzzy Logic controller. You have a table linking temperature with PWM setpoints. Fuzzy Logic calculates the output using linear interpolation between the points you have programmed in.
It might be possible to "learn" the correct mapping by having the code step with a small change in PWM and seeing how the temperature changes. You can then save the PWM step and the temperature step in your Fuzzy table. Getting that sort of thing to work nicely would probably be difficult.
Look up "Fuzzy Logic" in google.
(EDIT) However, since you have continuous temperature and control, it may be simpler to make a PI control loop in software. PI control loops can be tuned to cover a wide range of models.
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Correct me if I am wrong but it sounds as if you are using a "Feedforward" type of control? You have mapped the resultant temperature of your reactor to the input power and your algorithm interpolates or calculates the required power for a given temperature setpoint? You are not using the temperature as feedback?
Or is it that you do not have any control and are asking for some control code given the data you have supplied?
What kind of power control are you using? Triac chopping/phase control? SSR on/off control? FET PWM control?
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Another possibility would be to have two detectors, on near the reactor and one further away in a line. Assuming the detectors are fairly matched, the detector further away should give an indication of background count to correct the reading from the detector close to the reactor. However that is probably a very expensive solution.
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A quick question regarding the circumstances around the event. Did anything get close to the reactor during that time? Did you move close to it? Do you have anything nearby that can emit low levels of radiation like a good quality watch with luminous dials or an old CRT computer monitor? Just thinking of possibilities.
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Oh that is sad. Personally I do not want to exceed 10 bars never.
Would it be possible to add a gas safety release valve to the reactor so that if the pressure exceeds a limit it can safely vent the gas without having to stop the experiment?
