@BobH
I used some left over solution from a PC short run I did about 20 years ago. It was originally about 1 liter of solution made up from a bag of crystals bought at Jameco or Frye's . The unused portion was stored for at least 15 years in a soda bottle (PET?), in what used to be my darkroom, now the lab kitchen.
BTE-Dan I wonder what the half life of conventional wisdom is. Research pushes the boundaries to change the current conventions. Eric Walker The effect of oxygen on surfaces or other impurities causing crystalstress, surface defects, quantum wells, band gap perturbations etc. all influencing exciton / phonon / photon interactions resonances, charge clusters and tunnelling in a myriad of variable ways. How do you suggest controlling at least some of the variables ?
How do you suggest controlling at least some of the variables ?
I think if I were running a series of experiments, I'd try to replicate someone who saw nominally unambiguous results, e.g., Piantelli for the NiH system, or something like the SPAWAR CR-39 experiment. Unless I had funding, I'd limit myself to inexpensive experiments that don't require fancy measurement instruments. I'd keep looking at patents, ICMNS proceedings and JCMNS articles until I found an experiment or patent where I also got those nominal results, sticking as close to the recipe as I could until I saw something interesting. Once that occurred, I'd attempt to boil the experiment down to its simplest basics, so that it's very easy and inexpensive to carry out. After that milestone, I'd run as many experiments as I could, controlling for a single input to see what effect there is on the output. (Sounds like a difficult several-year program.) My own reading up to now would bias me towards experiments that include heavier elements and that involve electrical discharge.
So initially I wouldn't try to control for possible effects of oxygen. I'd just cargo-cult the recipes at first, doing whatever they specify, without getting philosophical about the physics or even chemistry. Once I saw something promising and got through all of the milestones above, one day I'd look into the role of oxygen in this NiH experiment by attempting small changes.
@David Fojt
Hi David. Being able to match the H2 pressure profile from Parkhomov's successful experiment is why I built the computer controlled back pressure regulator. This is the pressure vs. temperature curve that I extracted from AP's reported data. I try to program my experiments to roughly match this profile:
@David Fojt
So, David, what are you saying is the correct stoichiometry? How much extra Li must be added to LiAlH4 to arrive at the correct stoichiometry? I have some Li metal that could be added to the fuel. Since there is abundant H, wouldn't adjusting the Li only affect the Li to Al ratio? What is the most desirable Li to Al ratio?
@David Fojt
To summarize, basically you're saying that to see results you have to continuously "play" with the reversible Li hydride reaction without allowing the system to reach equilibrium, and that a rather low pressure helps achieving this by lowering the decomposition temperature of the hydride?
EDIT: also:
AP powder worked because the mortar...As well as by some location" hydrogen condensing surface" was separated from the liquid lithium.
Do you mean that the liquid lithium must not form a coating on the active surface of the Ni particles, and that the reaction works/works better if there is a gap (even if short) between the decomposing hydride and the Ni surface?
Is this what you've seen in your experiments? Forgive me for asking this question, but if yes, it's exactly what I've been trying to suggest to Bob since a good while.
One of LFH's customers (who must remains anonymous at his own request) Is getting some positive results using a very very slow ramp-up. 1C a minute or so all the way up to 1200C. This customer also does interesting stuff to intensify the field by wrapping an unconnected coil of oxidised wire (non-conducting oxide forms on the surface) around the fuel tube proper. The protocol demands a lot of careful temperature watching in the hotter phases to avoid melt-downs, apparently you have just a few seconds to switch off the heat and avoid a runaway. I wish I could tell you more, but sadly I don't know much more, and like Me356 this one is mostly 'dark'. I am not even sure what his fuel is, definitely none of mine.
Releasing H quickly from the hydride and releasing it slowly (I suppose from the LiAlH4 in this case) seem mutually exclusive processes.
I'm not sure if I've noted this earlier in another thread, but I'm thinking there are probably two effects occurring here at the same time: one favored by the slow hydrogen release from the preferably ionic hydride and/or the active surface, and another by a rapid change in reactor conditions. Cyclically forming and decomposing LiH as suggested may be doing both at the same time.
From your report it sounds as if the first process occurs for a sufficiently long time (and I imagine, also in sufficient amounts), excess heat might eventually spontaneously arise.
I'm not sure I understand where the unconnected oxidized coil is located. Is it completely disconnected from the input electricity?
@David Fojt
That's a very significant confirmation if it's what you've observed; thanks. So, elemental Li/LiH is the active component and can work without adding Al/LiAlH4, but it requires higher temperatures and/or lower pressures and, I would add, a more durable reactor since in pure form it's quite corrosive and reactive.
I'm not sure I understand where the unconnected oxidized coil is located. Is it completely disconnected from the input electricity?
Yes, It is. I'm not totally sure how effective or neccessary it is, but this experimenter seems to be getting results - even if he is to slow to get to temperature - though of course, this does allow plenty of time for hydrogen to diffuse through the walls of the alumina tube.
Hydrogen atoms are very tiny. I suspect that they can easily pass through the walls of the ceramic fuel tube and escape from a t least that part of the system. They will- according to theory at least - diffuse though hot steel even faster.
Is that what the customer reported? Either the alumina tube is (or becomes after some time) leaky or the hydrogen which appears to leak is not ordinary hydrogen.
From data from experiments publicly conducted so far, I've got the impression that in absence of a leak alumina tubes can generally contain well hydrogen, even at high temperatures.
....if Inside pressure is always lower than outside, what's happen ?
DF
The Hydrogen can escape - this kind of molecular diffusion has little to do with the small pressure differentials we typically see in LENR experiments. If the tube losing hydrogen was also surrounded by another tube containing hydrogen, the pressures would be equal, because as much hydrogen would go in as came out. But when tiny hydrogen atoms/molecules pass through the tube wall into a gas made of bigger molecules, they cannot be replaced, since the big molecules of (say) oxygen, nitrogen, cannot get back inside. Like sieving peas (why would you want to do that?
) into a box of tennis balls- the peas can pass through the mesh and escape, but the tennis balls are too big to replace them.
ETA- my customer never mentioned this- these are my own thoughts.
Dalton's law of partial pressures should be valid, which implies that if the partial pressure of hydrogen in a hydrogen-filled container is higher than the partial pressure of the hydrogen fraction in the outside atmosphere, hydrogen will still eventually leak away from the container.
Nevertheless from what I've seen so far with properly fitted alumina tubes this is generally a very slow process; I was imagining an observably fast leak rate (or apparent leak) in this case, which may be expected if excess heat is associated with some sort of "condensation" of the hydrogen atoms into some other unusual state (EDIT: this is why I often remarked to check for unusual pressure drops where none would be normally expected).
Just to add, I dispensed with the SS tube I was using because it could not go to high enough temperature. It was a thin tube good only to about 800°C. I went back to an alumina tube with an epoxied tube seal adapter. The alumina tubes are 7.5" long closed on one end. The seal adapter is machined brass. Stainless steel would be better than brass for thermal expansion match. The epoxy must be thick in the seal region to be able to accommodate the thermal expansion difference. In this case the epoxy is about 0.012" thick. The epoxy I used was JB Weld, which is good to about 250°C. I have a heat sink to the alumina tube and I measure the temperature of the seal adapter during the experiment. With the active 2" end of the tube is heated to 1200°C, the seal only gets to about 60°C. I have tried removing the alumina tube when the experiment is done to see if the seal adapter can be re-used - I was unsuccessful. I end up cutting off the alumina tube with the ash inside and epoxy it closed to preserve it. Then I cut off the brass behind the stainless Swagelok nut so as to be able to re-use the nut. Presently I am using brass seal ferrules with the brass adapter.
When assembling the alumina tube to the adapter, I put the Swagelok connector on the seal first and seal it to another connector to set the ferrules. I do this first just to help protect the assembly from that swage-ing operation after it is assembled. Then I use a toothpick to apply a thin coating of the epoxy to the ID of the adapter and to the OD of the end of the alumina tube. I insert the alumina tube while twisting about 90°. Then I place the uncured assembly on a vertical rod with the adapter facing down - the rod extends about 6" into the alumina tube. This keeps everything coaxial since with the OD of the adapter being 0.025" larger than the tube OD, there is the opportunity for the adapter to be crooked. Now, I apply a slight meniscus of epoxy around the outside edge of the alumina side of the adapter (which is facing up). The JB weld hardens slowly, over the course of 4-8 hours, and takes 24 hours to cure. During that period, I will occasionally rotate the assembly by the adapter at the bottom to help insure no epoxy sticks to the rod holding the assembly straight (I have not had a problem with this yet).
Here is what it looks like at the adapter end:
I machine the adapter from 3/8" free machining brass rod stock that I get from McMaster-Carr. It is a simple operation on a lathe taking about 30 minutes. After machining, it is cleaned in hot detergent, rinsed thoroughly, and heated dry (this is not critical, but the oil must be removed). Here are the dimensions of the adapter:
One of LFH's customers (who must remains anonymous at his own request) Is getting some positive results using a very very slow ramp-up. 1C a minute or so all the way up to 1200C.
Could be an inexpensive type K thermocouple being brought close to the upper limit of its valid temperature range (e.g., 1200 C), or something such as green rot degrading the thermocouple.
Could be an inexpensive type K thermocouple being brought close to the upper limit of its valid temperature range (e.g., 1200 C), or something such as green rot degrading the thermocouple.
That is why it is always good to have an additional lower temperature measurement - a proxy - that is correlated to the high temperature measurement as a means to confirm its validity. I measure the temperature on the top of my insulating block. When the core is at 1200°C, this proxy temperature is around 350°C. It is less accurate, but it is a confirming measurement. Also, I don't expose my thermocouples to hydrogen - they are outside of the hydrogen envelope and are inconel sheathed. These inconel sheathed thermocouples are inexpensive, about $30 each from Omega.
I'd even say it's one of several arguments for mass flow calorimetry, if one has the patience and inclination. Although point temperature measurements are no doubt fine while one is pursuing a quick iterative approach, provided one is aware that there are some subtleties.
Could be an inexpensive type K thermocouple being brought close to the upper limit of its valid temperature range (e.g., 1200 C), or something such as green rot degrading the thermocouple.
I would agree Eric, but I have some other supporting evidence suggesting he is not dreaming. BTW Green rot never happens with these TC's, they are not exposed to sufficient hydrogen - they are in atmosphere in fact. I have had ordinary corrosion failures after many hours at 1000C plus though. But in every case of thermocouple failure I have ever seen they fail low, never high. The only exception to this general rule is if the TC amplifier board or the associated circuitry lost the plot. Then anything can happen.
Hydrogen atoms are very tiny. I suspect that they can easily pass through the walls of the ceramic fuel tube and escape from a t least that part of the system. They will- according to theory at least - diffuse though hot steel even faster.
Some experimenters use Fe2O3 = the Mills hydrino
catalyst to produce H*, which finally reacts with Lithium. H* is a resonant form of hydrogen, with half or one third the radius of H. H* will not undergo chemical reactions in a metalconductor and will easily pass through, if it can be protected to undergo magnetic reactions!
Just think how to use it!
