Posts by Eric Walker

Quote from Longview

Thorium sounds like a good candidate. Are there lighter weight alpha emitters that might give much higher output to mass ratio for such application?. Of course it would have to be an alpha emitter with relatively long natural half life, otherwise it would be exhausted too fast for long endurance power output.

As you suggest, I suspect there's going to be a tradeoff that is made between potential thrust and how long the alpha emitter lasts. Most of the alpha emitters are heavier isotopes. Alpha decay is not an all-or-nothing thing, and if there is a way to induce activity, it's possible that some lighter elements that appear to be stable are in fact only "quasi-stable" and that activity can be induced in these under suitable conditions (this possibility is discussed in [1]).

Quote from Longview

Is there other evidence of laser stimulation of alpha decay other than say Letts / Hagelstein?... it is a fascinating idea to me.

The Letts-Hagelstein paper is one of a number of experiments that lend themselves to an interpretation of "LENR-as-induced-decay." Think of any LENR experiment that shows a correlation between helium and heat, for example. Nonetheless I am open to there being several different things going on in LENR, all of which have escaped scientific scrutiny up to now, just because of the controversy surrounding the subject.

[1] http://bit.ly/1MSS90U

Quote from Longview

Again, is there a good link to a credible-to-you description of the Papp engine?

I saw a garage experimenter from Australia or New Zealand present a video on Youtube of a simple device that seemed worked, but I can't find the link. Russ Gries has attempted to build a so-called "popper," without success, if I recall, but I believe the general design will be similar to a working prototype [1]. (I suspect Gries was focusing on the gas mixture and on a magnetic field and didn't use a suitable alpha emitter.) Bob Rohner of the Rohner Group has been working on a demonstration "popper" which provides a simple demo and which Michael McKubre, a researcher involved in LENR at Stanford Research International, seems to think was legit [2]. If you ignore Feynman's claim of a hoax, you can see Bob and Tom Rohner testing and running a working engine for Josef Papp in a series of videos on Youtube starting with [3].

Unfortunately I cannot provide a link to a simple description that I know for sure to work, but Rus Gries's videos might be a good place to start.

[1] http://bit.ly/1kodAf7
[2] http://bit.ly/1jStDBt
[3] http://bit.ly/1GoFvp4

(LENR Forum insists on inlining the videos into this post, so I'm running the links through bit.ly.)

Quote from Longview

BTW, What is good reference link for Papp, that you find convincing and simple enough for those with at least basic college physics and chemistry for majors. Thanks!

Papp's third patent provides a good technical overview [1]. Beware, though, because he either made the whole thing unnecessarily complex (e.g., with the description of the complex set of steps needed to prepare the gasses) or his lack of mental balance led him into whacked out theories on what was going on. A pair of entrepreneurs who think they figured out what made the engine work think that noble gasses aren't even needed and that air can be used [2]. That points another finger to whatever was being subjected to the electric arcing (e.g., thorium) rather than a special mix of noble gasses.

All of this aside, one thing that is cool about the engine design is that if you can control the activity of an alpha emitter, using it to ionize and expand an inert gas sounds like a very efficient way to make use of the energy that has been released.

[1] https://www.google.com/patents/US4428193
[2] http://bit.ly/1W4o44d

Quote from Longview

I suppose that the "thrust" can to used to do work on something other than a piston or turbine. I suppose that puts us back to ion thrust engines, which work OK in space.

That's the idea I had. Take thorium and shine a laser at it or run a current through it, and, if my hunch is correct, the activity will increase during the laser pulse or current. This would, then, be an enhancement of the existing ion-thrust approach. If we had a LENR battery, it could be used to drive the laser or electric current.

The Papp engine comes in only insofar as Papp might have been exploiting a previously unknown detail about alpha emitters such as thorium.

Yeah, read the article and the other stuff available. "Hoax" and "scam" are what the wikipedia guardians and Feynman called it.

Quote from Mary Yugo

I suppose so, in the same sense as "pigs can fly."

Here is why I think it might have been real:

http://physics.stackexchange.com/q/212660/6713

Hopefully you will be kind enough to apply your knowledge of this area of physics to answer my question negatively, which will benefit the physics graduate students and professors who, along with me, are waiting for an answer.

Quote from I Inventzilla

Most published LENR experiments recorded excess heat in the megawatt range.

Perhaps you mean "milliwatt" (or watt). It would be nice if we were seeing excess heat in the megawatts, though.

Quote from Mary Yugo

Papp was a schizophrenic, sociopathic con man. A relative of mine was a physician who treated him in the 1960's for a self-inflicted gun shot wound. Papp claimed a hit man did it. According to my relative, who knew Papp, the guy was a flaming nut case. A total whack job. BTW, noble gases do not and can not provide free energy.

Everything you say may be 100 percent true, and Papp's engine might still have had something cool going on with it. In particular, I think the electric arcing might have accelerated the decay of the thorium alpha emitter he was using. Do you disagree that this might be something that is possible?

Quote from Tyy

^If you mean you're convinced the Papp engine is real, you are beyond all resonable help.

Care to elaborate? (Seriously.) I can elaborate for my part on why I think it might be real.

For space propulsion, I think the Papp engine would be a better fit than a heat engine. I am starting to become convinced that it's real, as well as that what's going on with it is related to PdD LENR helium production.

It is a bit unfortunate that so little is known about this engine that focusing on it would not be an effective way to win over Airbus engineers.

Also, it's not safe to assume that all heat-generating reactions result in transmutations that deviate from the natural ratios. (Although I agree that notable transmutations are also interesting, and have been seen, btw.)

Quote from me356

Radiation peaks are around 50 CPMs.

Are you using a GM tube? Do you have access to an instrument that will give the energy spectrum of whatever is causing the clicks? Have you tried your current radiation detector against a calibration run to verify that there are no clicks at that time?

Quote from backyardfusion

I might run down to the lab technician tomorrow and have a go at winning him over, but the chances of that working are slim.

If no one at the high school can help, perhaps you live near a university where there might be a sympathetic engineering professor?

Quote from H-G Branzell

Some of these speeding alphas will collide with nearby nucleuses and cause secondary nuclear reactions that will produce, guess what. Yes, gammas.

Out of curiosity (somewhat unrelated to this thread), as a thought experiment, do you have a sense of the upper limit on the energy that alpha particles in a strong flux could carry away below which their effects would be relatively harmless, when the shielding provided by the apparatus is taken into account? If you like, we can think of the energy in terms of the peak of a Maxwell–Boltzmann distribution.

Hi Mary,

It's been a while.

Quote from Mary Yugo

Yet, early on, Rossi said that ALL of the excess heat generated by the ecat came from thermalization of gammas.

I don't think I ever found the gamma-thermalization claim credible; or, if I did, it was before I knew anything about gammas.

I don't consider myself a Rossi booster, although I'm not skeptical of his whole project to the extent that you are.

Regards,
Eric

Quote from H-G Branzell

Alpha and beta particles can be stopped efficiently in matter, but this process will also generate gammas or X-rays.

X-rays are definitely seen when sought out. My impression is that they are commensurate with heat. Because they are not penetrating enough in general to escape the container, they will not be detected outside several layers of interposing material. I assume that one possible source of the x-rays is prompt particles. There could be others.

Gamma rays, if produced in quantity, would not be all that useful, as they are penetrating and therefore hard to thermalize. But that is a practical consideration. As to why they don't occur in quantity, either from primary reactions or from de-excitation of nuclei excited in inelastic collisions, is a question to be understood, to be sure. If two alphas are produced, each carrying 0.5 MeV, that will put an upper bound on an deexcitation gammas that can be produced as a byproduct. Now we're in hard x-ray territory.

I find it helpful to recall that the purported reactions are occurring in a very different environment from ones typically studied either in plasmas or in ion-bombardment experiments. One important difference is the electron charge density. Those electrons are pervasive throughout the area and possibly provide a target for EM coupling in one or another context. We should avoid unintentional overconfidence in the applicability of our current knowledge about nuclear transitions. The history of science shows over and over how unfamiliar circumstances merit careful study and can lead to exciting and unexpected results.

Hi Andrea,

Thank you for responding directly to my comment. An interesting deck of slides you've put together. I'm still trying to understand the precise mechanism you propose, but it seems to be refreshingly different.

Quote from Andrea Calaon

Please consider that all reactions producing neutrons, but one, are endothermic and require large amounts of energy.

I had in mind neutrino-producing reactions rather than neutron-producing reactions, i.e., ones where leptons are a daughter. Your theory may not require them to occur at any significant rate. But if the daughters are important for explaining something else, there will need to be an additional explanation about the weak interaction. (I think you've clarified that these reactions are rate-limited in the expected way.)

Regards,
Eric

I had a hard time understanding the precise mechanism involved in bringing about nuclear reactions in Adrea Calaon's theory.

But in Calaon's slides he proposes a number of possible reactions, a good portion of which have neutrinos as daughters. This means the weak interaction would be involved. The weak interaction is incredibly slow compared either to the electromagnetic force or to the nuclear force. For this reason reactions involving the electromagnetic and strong interactions can be expected to outcompete those involving the weak interaction by many orders of magnitude in any normal circumstance, apart from radioactive decay (which is not a "reaction"). (This is why the sun's fuel is consumed so slowly.) If Calaon's theory requires that any of those reactions involving the weak interaction appear in significant quantities, he needs to explain what makes the weak interaction speed up. (This is also one of the difficulties that Ed Storms faces.)

Quote from H-G Branzell

If this turns out to work I will have some pardons to beg for, I am afraid. But at first I would like to see some gammas. It does not matter how you upset an atomic nucleus. When it retaliates we know what it does, I am pretty sure.

The lack of gammas is a perplexing issue. By "lack" I do not mean complete lack; there are gammas that are seen from time to time, but not anywhere near an order commensurate with the heat that is developed.

I think it would be unwise, however, to pin an expectation on the appearance of gammas commensurate with heat in order to allow that the process is nuclear in nature. There are several ways one can think of offhand to avoid them -- only two-body reactions are selected; only light elements, without excited bound states, participate, etc. There may be ways we can't think of to avoid them. But perhaps out of concerns similar to yours, researchers such as Robert Duncan have referred to the whole matter as the "anomalous heat effect," avoiding the question of whether it's nuclear.

Quote from barty

@Tyy: and why is the US NAVY Lab agreeing the results of Rossi, based on their own work?

It's important to know more about the involvement of the Navy lab. Sometimes the opinions of employees of an organization are just their own, even when a slide deck carries the logo of the institution they work for. The logos on the slide deck generally cannot be taken to imply that an official position is being communicated.

Quote from barty

When I understood correctly, then this paper could be the biggest event since Fleischmann and Pons!

It is welcome news for watchers of this field to see a new replication from a research lab affiliated with a well-known organization. But in practical terms I doubt it will move the needle much. Consider the major labs that already have or have had researchers dabbling in LENR: Airbus, SPAWAR, Mitsubishi, Toyota, NASA, SRI, the US Naval Research Laboratory, AIMS, ENEA, Tsinghua, the University of Missouri, and, in the early 90's, Stanford. It is easy for people to write off these other efforts as the hobbies of mavericks within the institutions.