Posts by magicsound

Quote from Paradigmnoia

One could wind up a custom heater coil with whatever feasible characteristics as desired

It's probably not a good idea to put a bare heater wire in the cell, despite the possible increase in available IR emission. At low vacuum and high heat there will be metal ions from the wire spreading around in the cell. The heater used by Mizuno is sheathed in stainless steel and was likely chosen for that reason as well as others. The sheath is also electrically isolated from the heating power, an important detail in my experience.

I've proposed a stainless steel thermo-well with cartridge heater(s) inserted in it as a low-cost alternative. For those interested, suitable tubes are available for around $12 from brewershardware.com

AlanG

Quote from THHuxleynew

For concentric cylinders the thermal conductance (W/K) is given by L*2*pi*theta/(ln(R1/R2) (theta = 0.3W/m-K). That is ~0.1 W/K, so for say 600K difference in T we have 60W transferred for L=0.2, R1/R2 = 20. (someone should check this).

Your ΔT at 600K seems a a bit high. If the outer tube's inner surface is at 200°C, that would put the heater at 800°C, probably above its safe operating temperature, though it might reach that at the high end of reported input power (300 watts?). I think ΔT=400K would be more realistic.

Your R1/R2 ratio needs some thought as well. Since the length of the heater sheath is 2 meters, it must be folded into 3 or 4 runs to fit into the cell. Its outer diameter is given as 2.8 mm; if 3 lengths as folded, R2eq for equivalent surface area would be 4.2 mm, and for 4 lengths of heater R2eq=5.6 mm. The cell tube inner radius R1 is given as 53.8 mm, so R1/R2 would be 12.8 for 3 heater lengths or 9.6 for 4. This ignores possible shadowing and similar effects within the bundle of heater sheath runs.

And if L refers to the length of the concentric cylinders in meters, that should be 0.6 or 600 mm as described.

Quote from gerold.s

I would like to come up with a simplified mathematical model of the internal heater and the outer cylinder. I assume that since the pressure is that low 1-3 mbars heat transfer and convection can be neglected. Therefore we have only radiation between heater and outer wall. Please correct me if i am wrong. If you have reliable info i can then crosscheck what i have available. Thx

I'm a bit sorry to complicate this seemingly endless argument, but some assumptions made in this discussion need questioning:

The thermal conductivity of Deuterium is the highest of any conventional gas, and is nearly 6 times that of air. Further, the conductivity does not decline much with pressure (until below a critical point ~10 Pa) and increases significantly with temperature. At the ~100-300 Pa pressure recommended by Mizuno, it is 0.21 W/m-K at 20°C and 0.30 W/m-K at 300°C.

In contrast to this, the convective heat transfer in the cell is determined by the specific heat and thermal viscosity of the gas. These are rather low for Hydrogen and Deuterium due to the low mass of the gas molecules. It may be that both convection and conduction are of trivial magnitude compared to the radiant energy, but we won't know until/unless someone looks at the numbers. Having now raised the issue, my part in this is done....

Here are a couple of references with useful data:

http://www.ethermo.us/Show7Vatemp!573.15!1~press!6!2.htm Excellent on line modeller for gas thermodynamics and transport properties

https://www.engineersedge.com/…al-conductivity-gases.htm

I like the HP/Agilent 65XX series of analog supplies. They're widely available on eBay and surplus electronics dealers for $500 or less. I got a 6555A for this project, $220 with shipping. It's 0-120 vdc @ 0-4a, and 500 watts max. It has both constant current and constant voltage adjustments, and fully isolated output. These weigh around 35 kg and are beautifully built and very reliable. Some versions with GPIB interface may cost a bit more.

AlanG

My initial report on the Ni mesh preparation:

https://bit.ly/2Mv13HY

This is a "Live Document" and will be updated periodically as the work continues.

AlanG

The only temperature limit given in the manufacturer's info is 200°C for the end "sleeve" where the lead wires are fastened. The sheath is steel, with MgO insulation. The heater wire is Ni or perhaps a Ni alloy like nichrome, so all the parts are pretty good for high temperature. As long as the "sleeve" end of the heater is outside the cell, the sheath should be OK up to 500°C at least. I suspect that could be easily exceeded in vacuum, so conservative application of power will be needed during the bake-out. Start low and beware of the long thermal time constant of the cell, while watching the outer surface temperature.

Regarding the power supply, I'm using a HP/Agilent 6555a, which has fully isolated output and both current and voltage limiting. It's an old-school analog supply, so lower risk of the residual output noise often seen from a switching supply.

AlanG

Very interesting comment Jed. The Mohs hardness refers to the scratch resistance - the ability of harder material to scratch softer material. The Brinell hardness (and similar Vickers scale) refers to indentation hardness - penetration of a calibrated indenter into the tested material. So while Ni is apparently harder to indent, it is softer to scratching (removal of material) by Pd.

Perhaps annealing the Pd before the rubbing would reduce the possible tendency to remove Ni rather than depositing Pd on its surface.

from https://www.ganoksin.com/artic…-annealing-and-soldering/

"Palladium is easily annealed with the use of a fuel-oxygen torch, with natural gas or propane and oxygen recommended. Flux is not necessary. Using the high-heat soldering surface and shade five or higher eye protection, adjust the torch to a slightly reducing flame, heat the palladium to a mild orange color, and hold for 10 to 30 seconds. The thicker the metal, the longer you must anneal it."

and a comment there: "Anneal to dull red and then leave to cool to room temp, also stops it from cracking."

Quote from Paradigmnoia

Since the sheath heater is within the reaction clean zone, it’s composition should be verified.

It is "steel". From the Sakaguchi catalog page (English):

"The Type M-2 flexible heater is made of ultrafine pipe with two heating elements held firmly in a heat-resistant steel capillary by a high purity inorganic insulator (MgO), designed for use in various places"

AlanG

Quote from THHuxleynew

I got the impression from the paper + Jed's explanatory comments that for the R20, the heater was coiled and than in physical contact with the reactor inner surface and/or mesh.

That is not correct. The schematic drawing on pg. 14 of the R20 report clearly shows the sheath heater is positioned at the central axis of the reactor tube and not in contact with the Ni mesh. Putting it inside a thermo-well at the same location might change the calibration of temp vs. input power, but the thermal transport inside the cell would not be changed. The specified heater has a steel sheath, so quite similar in emissivity to that of a steel tube used to contain it.

AlanG

HIq neH yItlhutlh jIH wo' chenpu' nuqDaq woj choHwI' 'oH lenr HoS

While I appreciate the concern of the moderators for possible toxic hazards of rubbing two metals together, I don't think a glove bag or box is needed for the rubbing process under discussion. Nickel is about twice the Brinell hardness of Pd, especially after having been worked hardened as woven wire. So there's no real risk of free Ni nano particles being created. Palladium is inert and considered non-toxic in elemental form, and is widely used in jewelry and in catalytic converters without associated health warnings.

That said, use of gloves is always advisable when handling metallic Nickel, due to its known skin toxicity, and the sanding process should be done under running water to carry away any resulting Ni particles. This is common practice when sanding urethane paints and other materials with known toxicity. Adding a particulate breathing mask is a good idea if in doubt of your skills, or lack experience in mechanical fabrication.

AlanG

Last call for Sakaguchi flexible sheath heaters as specified by Mizuno. I'll be placing the order tomorrow (18 July) at around 20:00 UTC. Cost plus shipping and customs fees comes to $120 each for US delivery. Contact me thru PM here or alan at magicsound dot us

AlanG

Quote from Cydonia

we shouln't care about heating type, guys, or its length. the main thing is not to exceed 3W / cm2 to make FIR.

By surrounding a simple, short resistifive wire by a big metal tube would do the same thing.

If you are correct, the simplest solution and one worth trying is a thermowell down the center axis of the cell, with a cartridge heater inserted from the outside. This avoids the potential leakage problems of power pass-thru fittings. However, the IR emission of the heater is thought to be an important part of the reaction process, so surface area of the folded sheath heater may be essential for a successful replication. Heat conduction from the thermowell tube into the end cap also complicates the calorimetry and internal heat distribution.

AlanG

I contacted Sakaguchi directly by email and received a reply in about an hour. They quote a unit cost of US$78.00 exclusive of shipping, tax and tariffs, which may be substantial. The unit shipping cost will be lower with a quantity order, and I therefore offer to consolidate orders from others who need the parts for accurate replication. I expect the all-in unit cost to be around US$120 including domestic re-posting. If you'd like to participate in this, please contact me by PM here, or off list - alan at magicsound dot us. Quoted delivery time is 35 days after receipt of payment, so I will be placing the order by the end of this week. If the order arrives in time, I can also deliver by hand at ICCF for those in EU.

Here is the technical specification document for the heater:

https://drive.google.com/file/…8lorCKW9/view?usp=sharing

AlanG

After a bit of struggle with the MonotaRO website, I did find the page for the heater Jed specified:

https://www.monotaro.sg/g/03032749/

The manufacturer is Sakaguchi E.H VOC, p/n 1M2500

Choosing 500 watts gives the sheath diameter as 2.8 mm and 2000 mm length. The price is quoted as 149.90 SGD (Singapore Dollars), or US$110.53. Shipping time looks like about 1 week ARO.

** There is no flange on this heater, just the sheath. We need additional details of how it is mounted through the CF end plate in a way that is gas-tight. I would use a Swagelok pass-through but better if Jed can specify a part number and attachment method eg. welded or screw-in.

MonotaRO doesn't seem to ship to USA, and Sakaguchi has no distributor outside of Asia, so substitution seems unavoidable. There's nothing suitable at Omega or McMaster. The search continues...

AlanG

What is the time frame of Google's question? If they don't need an answer tomorrow, I would suggest they wait (90 days?) for results of the several Mizuno replications now apparently under construction. If there are positive results, even if not conclusive, Google would do well to jump in. As Jed rightly points out, the Mizuno material is simple to prepare compared to most others, and the XS claimed is substantial enough to be unambiguous and easy to measure. Who knows, maybe they are already doing a rep.

AlanG

I think the coil used in our earlier tests is a functional part of the resonance phenomenon. Because water has a rather high dielectric constant (~80), the immersed electrodes have substantial capacitance. Thus a series resonant LC circuit is formed with the coil. The waveform shown in my test here clearly shows resonant response to a conduction impulse.

Quote from can

n replications performed last January-February (last test here) Magicsound used one very similar to what you linked, and in fact it was a slower low-voltage version of the same detector: https://www.lndinc.com/products/geiger-mueller-tubes/7317/ It was observed earlier on to be sensitive to RF emitted by the discharges that the experiment inherently created and it was somehow fixed along the way along with related issues with other detectors, but such sensitivity apparently remained on the neutron detectors and to a limited extent his NaI gamma spectrometer.

I found that the metal case in which the LND7317 pancake tube was mounted had no ground connection. This resulted from the peculiar circuit of the GMC-320+ used to power and detect the tube signal. That circuit has the detector front end amplifier connected at the cathode of the tube (its metal case), measuring the current through a small series resistor. To make this work, the tube case is insulated from the box in which it is mounted. Adding a separate system ground wire for the box cured the RF sensitivity.

For context, this experiment was meant to characterize high current arcing between closely spaced plates in an electrolytic cell. I measured the di/dt of mechanically-induced sub-mcrosecond arc events at around 10k amperes/second. Peak currents from unloading the large V+ air-core inductor were on the order of hundreds of amperes. In another test at ~10 amperes continuous electrolytic current, I detected sustained oscillation with pulses of ~228 MHz sawtooth-like waveform at about 3 KHz repetition rate. In other words, LOTS of RF energy, around 100 watts RMS. So I was not surprised when my sensitive Li6I neutron scintillator wasn't happy.

This was meant to be both speculative and humorous.

For example, suppose that we have a vortex of strange EVOs in n-space such that the polarity of gravity inside the vortex horizon is negative. The Hilsch effect in such a vortex will be reversed, so that the nodes with lower kinetic energy (eg. cold particles) will move to the outside of the vortex frame, while the high energy nodes will collapse to the center of the vortex.

If the center of the vortex is a trans-dimensional gateway (as has been proposed by a certain forum participant A***), the hot particles will escape from our 3-space frame through the singularity, while the cold ones will exit the vortex as Feynmann radiation.