I
You might use an oil pump for rough, and some can get to 10E-4 t but if you use them you need a foreline trap, inline molecular sieve filter or something similar.
Likely Typo: 10E-4 in computer scientific notation is 10 x 10^-4 = 10^-3. You probably meant 1E-4 = 1x10^-4 = 10^-4 = 1/10000
I also recommend the use of a foreline trap - but you need a physical barrier either side of the zeolite molecular sieve to ensure the pump cannot eat the beads. A fuel filter like this, double-sealed with epoxy resin on the joints will do the trick but you must pay careful attention to all the line connections.
https://www.ebay.co.uk/itm/Uni…id=p2047675.c100005.m1851
This is the molecular seive- you will only need a fraction of this amount.
Likely Typo: 10E-4 in computer scientific notation is 10 x 10^-4 = 10^-3. You probably meant 1E-4 = 1x10^-4 = 10^-4 = 1/10000
No typo- it is an the old "classic way" of writing Scientific notation see for example: http://albert-cordova.com/_science/exponent.html
10E-4 t is 0,0001 torr or 0.1 microns.
Notice many high vacuum gauges use the notation: https://mse.ndhu.edu.tw/ezfile…ST18-U8-pressuregauge.pdf
It seems you are living in the virtual computer world of notation and not in real life laboratory world.
double-sealed with epoxy resin
Yes, they even sale "torr seal" good to 10E-9 Torr but it is pricey.
It is just clear epoxy with no plasticizers. -
If you use it, keep your bake out below 120C.
If you use epoxy, be sure it is the clear kind without "fillers".
Some are loaded with barium sulfate and metal - not good for such things.
Some are loaded with barium sulfate and metal - not good for such things
Yes- stick with traditiona clear 2 pack slow cure epoxies - not JB Weld metal-filled leakproofers for example.
Display MoreNo typo- it is an the old "classic way" of writing Scientific notation see for example: http://albert-cordova.com/_science/exponent.html
10E-4 t is 0,0001 torr or 0.1 microns.
Notice many high vacuum gauges use the notation: https://mse.ndhu.edu.tw/ezfile…ST18-U8-pressuregauge.pdf
It seems you are living in the virtual computer world of notation and not in real life laboratory world.
Whatever world I am living in, 10e-4 is not normalized. And this comes from the days of Fortran II (1958) and surely even if you are oldguy, your use of this convention doesn't predate 1958. The convention carried thru to today in all languages for their default display.
The mantissa is suppose to be between 1.000... and 9.999... and 10>9.999... I don't see any non-normalized numbers in Ming-Show Wong's 2018 paper that you cited, and regardless, it is non-standard and thus confusing. The Tracy Albert html page on "exponential notation" you cited is not any standard that exists and therefore is wrong (showing all non-normalized non-standard "scientific notation") and would needlessly confuse any high schooler learning scientific notation. What Mr. Albert means when he shows an "E" is the "^" which on ASCII is the way to write an exponent, thus 1.0*10e-1 should b 1.0*10^-1 which if he had a non-ascii character set would be 1.0*10-1.
The correct way of displaying what it is I think you mean by 10E-4 is:
10-4 = 0.0001 = 1/10000 = 1e-4.
See:
https://www.quora.com/What-does-1e-4-stand-for
Modern computer languages do the same:
R:
> .0001
[1] 1e-04
Python:
>>> 1e-4
0.0001
>>> 10e-4
0.001
Wikipedia:
https://en.wikipedia.org/wiki/Scientific_notation
Quoting the Wikipedia:
Normalized notation
Main article: Normalized number
Any given real number can be written in the form m×10n in many ways: for example, 350 can be written as 3.5×102 or 35×101 or 350×100.
In normalized scientific notation (called "standard form" in the UK), the exponent n is chosen so that the absolute value of m remains at least one but less than ten (1 ≤ |m| < 10). Thus 350 is written as 3.5×102. This form allows easy comparison of numbers, as the exponent n gives the number's order of magnitude. In normalized notation, the exponent n is negative for a number with absolute value between 0 and 1 (e.g. 0.5 is written as 5×10−1). The 10 and exponent are often omitted when the exponent is 0.
Normalized scientific form is the typical form of expression of large numbers in many fields, unless an unnormalized form, such as engineering notation, is desired. Normalized scientific notation is often called exponential notation—although the latter term is more general and also applies when m is not restricted to the range 1 to 10 (as in engineering notation for instance) and to bases other than 10 (for example, 3.15×220).
E-notation
A calculator display showing the Avogadro constant in E-notation
Most calculators and many computer programs present very large and very small results in scientific notation, typically invoked by a key labelled EXP (for exponent), EEX (for enter exponent), EE, EX, E, or ×10x depending on vendor and model. Because superscripted exponents like 107 cannot always be conveniently displayed, the letter E (or e) is often used to represent "times ten raised to the power of" (which would be written as "× 10n") and is followed by the value of the exponent; in other words, for any two real numbers m and n, the usage of "mEn" would indicate a value of m × 10n. In this usage the character e is not related to the mathematical constant e or the exponential function ex (a confusion that is unlikely if scientific notation is represented by a capital E). Although the E stands for exponent, the notation is usually referred to as (scientific) E-notation rather than (scientific) exponential notation. The use of E-notation facilitates data entry and readability in textual communication since it minimizes keystrokes, avoids reduced font sizes and provides a simpler and more concise display, but it is not encouraged in some publications.[3]
Examples and other notations
In most popular programming languages, 6.022E23 (or 6.022e23) is equivalent to 6.022×1023, and 1.6×10−35 would be written 1.6E-35 (e.g. Ada, Analytica, C/C++, FORTRAN (since FORTRAN II as of 1958), MATLAB, Scilab, Perl, Java,[4] Python, Lua, JavaScript, and others).
I also recommend the use of a foreline trap
I like the ones that open and easy to clean and replace the sieve material
and also the ones (like Edwards) that have the purge valve.
These things become a large reservoir for materials (water, nitrogen, hydrogen,....)
and I like to be able to purge (say with D2( and valve them off.
Ideally they shouldn't see much other than your working gas but things happen-
a valve left open or a leak or.... then it is a long time of pumping to clean things up again.
Especially, since the pumping efficiency of a turbomolecular pump is less for H2 (it is a mass thing).
I also put a heating pad on my forepump to help clean them up.
Display MoreI like the ones that open and easy to clean and replace the sieve material
and also the ones (like Edwards) that have the purge valve.
These things become a large reservoir for materials (water, nitrogen, hydrogen,....)
and I like to be able to purge (say with D2( and valve them off.
Ideally they shouldn't see much other than your working gas but things happen-
a valve left open or a leak or.... then it is a long time of pumping to clean things up again.
Especially, since the pumping efficiency of a turbomolecular pump is less for H2 (it is a mass thing).
I also put a heating pad on my forepump to help clean them up.
You have been at this a long time. Can you tell us if you know any of your colleagues intending to replicate Mizuno?
A credible source told me of a familiar name who had achieved the kW level. I contacted him, and he said I must be mistaken. Not sure if that rumor was in regards to replicating Mizuno, or something already in the works. This soon after the paper was released, I am guessing the latter. I also see fabrice DAVID has a couple high school students in the US starting on this.
Python:
>>> 1e-40.0001
>>> 10e-4
0.001
If true, suggests the writers of Python may have been seriously short in the exponents of 10 business. For a simple example, 10 raised the the "minus one" power is by definition simply 1/10 = 0.1, likewise and by definition, 10 raised to the minus 2 power is simply 1 divided by 10 squared, that is 1/10^2, or 0.01 or "one hundredth".
As we all know, 1 raised to any positive power is simply 1, and by inference 1 raised to any negative power is simply 1/1, 1/1^2, 1/1^3 etc. And hence also simply "one". Such notation ostensibly from Python above seems at odds with basic exponential notation and its related algebra
We're going to see more of this, I fear. What concepts, and programmatic idiosyncrasies, rather an actual old fashioned engineering training, might have led to the failures of the Boeing 737 MAX MCAS/ACAS system?
Display More>>> 10e-4
0.001
If true, suggests the writers of Python may have been seriously short in the exponents of 10 business. For a simple example, 10 raised the the "minus one" power is by definition simply 1/10 = 0.1, likewise and by definition, 10 raised to the minus 2 power is simply 1 divided by 10 squared, that is 1/10^2, or 0.01 or "one hundredth".
As we all know, 1 raised to any positive power is simply 1, and by inference 1 raised to any negative power is simply 1/1, 1/1^2, 1/1^3 etc. And hence also simply "one". Such notation ostensibly from Python above seems at odds with basic exponential notation and its related algebra
We're going to see more of this, I fear. What concepts, and programmatic idiosyncrasies, rather an actual old fashioned engineering training, might have led to the failures of the Boeing 737 MAX MCAS/ACAS system?
No Longview -- it's the standard and you are just not reading 10e-4 as described in the standard. But that's OK. It literally is DEFINED as 10 x 10-4 in the standard. If you want to read it in a non-standard way, that is up to you. But we can be certain that "the writers of Python" have not "have been seriously short in the exponents of 10 business".
"If true". If you have a Mac, open a shell and type "python<enter>" and try it yourself and you will get the same answer. If you have a PC you will have to download and install Python. On Mac, Python is installed by default. If you don't want to install Python, do it on Excel on your PC. Try entering 10e-4 in a cell on an Excel spreadsheet. All the programming languages implemented the standard developed in Fortran II in 1958. A good standard last forever.
What more can I say -- nothing. But if you are communicating with the remaining people who know what 10e-4 means, you are confusing them because it means on any computer language 1/1000 and nothing else. It's a mistake.
I understand your position and argument. That it "10e-4" "is literally DEFINED as 10 x 10-4 ". Fortunately, it is not likely to be my problem at this late age. I rarely use the notation you mention, other than foolishly pasting it in from some other source. I would now not recommend it to anyone.
That authors of computer programs, and hence their followers, in failing to follow the rules for exponential notation set up over the last 100 yrs, court disaster, but what's new? Personally I recommend the use of the "^" symbol or the superscript equivalent, then no one will be left wondering why "-4" suddenly refers to one thousandth rather than a "ten thousandth". The leading "10" suggests to me that the base of exponentiation in that particular case is "ten" rather than 2 or "e" or some other base.
IMHO, the convention you are advocating is "way out" from intuitive, and could crash any laboratory exercise, or an important engineering effort . An order of magnitude is a lot of error to court because of poor attention to math notational fundamentals.
By the way, "e" has quite another meaning we surely all know. Borrowing that centuries old designation for "exponent" is yet another invitation to unintended blunder.
I was thinking of supplying D2 via electrolysis of D2O and filter the D2 out with a Palladium disc which I own from a previous project. The R20 seems attractive because it is simple. My diagram attached does not show the RGA or the Vacuum Gauge.
Use a dry scroll Vacuum Pump:
by Agilent Technologies
IDP3B01 Agilent IDP 3 Dry Scroll Vacuum Pump
www.amazon.com/IDP3B01-Agilent-Scroll-Vacuum-Pump/dp/B01F73OO88/ref=sr_1_2
Price: $2,778.58
Full Range Appion Vacuum gauge:
www.amazon.com/Appion-AV760-Range-Digital-Vacuum/dp/B00VKGQ6OW/ref=asc_df_B00VKGQ6OW/
Hydrogen generator: www.fuelcellstore.com/horizon-hydrofill-pro-fch-020
PFEIFFER TMU 261 P TURBO PUMP WITH TC 600 CONTROLLER, DN 100 CF, PMP02826 / PMC01720
http://www.ajvs.com/new/product_info.php?products_id=7871
Risudual Gas Analyzers:
Let me know what items are bad choices.
dartin
You need to realize that the notation of 10E-4 is common in vacuum gauge terminology. You are trying to apply computer terminology instead. It is like talking to some one from the UK about billions. You must use the terms in context.
You might want to do a google search on vacuum 10E-4 and see what you get
example: http://www.fusor.net/board/viewtopic.php?t=3592
"The Torr - this is the simplest and most useful of all vacuum units and is universally spoken due to its being constantly discussed as powers of ten. 1 torr = 1 mm of pressure. 760 torr= 1 atmosphere. 1 micron =10e-3 torr, etc High vacuum begins roughly at 10e-4 torr = 0.1 micron."
https://www.avsforum.com/forum…ave-learn-hard-way-6.html
"10e-4 to 10e-6 Torr (1/10,000th to 1/1,000,000th of a Torr):
Give consideration to what terms are use in selling most vacuum pumps and gauges.
The discussion is about vacuums not computer programing.
But for the record I started with Fortran (and ALGOL, macro 10,.... )
The D2 will get through the Palladium filter at about 4.5 times the rate of H2. If the D2O is pure, that shouldn't matter. We don't need much D2 to operate so things should work. I put in a couple of valves to measure the amount of D2 provided. I may need a pressure gauge in the bulb to more accurately represent how much D2 was used.
BTW, if one writes 3.4*10E-4, it should be clear. 3.4E-4 would be shorthand for those who agree on what it means.
dartin
Full Range Appion Vacuum gauge:
www.amazon.com/Appion-AV760-Range-Digital-Vacuum/dp/B00VKGQ6OW/ref=asc_df_B00VKGQ6OW/
You can do better for the money with a Pirani type digital vacuum gauge which can go to 0.1 micron i.e. 10^-4 Torr from Lesker or Instrutech for around $400. Google for it and you will find the manufacturer and distributors.
You may be able to use a cheaper rougher (backing) pump on your Turbopump as $2700 seems high and this one only goes to 250 mTorr (i.e. 2.5x10^-1 Torr). See what the specs are for the backing pump on your turbopump. Without doing more research, I feel as if this pump has more capacity (i.e. liters per minute) than you need for a backing pump to your turbopump. The turbopump is the high cost item on your vacuum system.
Didn't look at the rest carefully. How much for your Turbopump and how much for the RGA. Good luck.
It literally is DEFINED as 10 x 10-4
not so
Just Google meaning of 10E-4
and you get:
"1/10000 = 0.0001 = 1 x 10e-4. 0.00044 = 4.4 x 10-4. As you can see, the exponent of 10 is the number of places the decimal point must be shifted to give. the number in long form. A positive exponent shows that the decimal point is shifted that number of." Notice that 1 time anything is itself.
It means 10 to the exponential (-4)
Some people are sloppy and write 10-4 but everyone knows that is just 6.
But yes, most people now a days use the ^ and it is clearer. However, you will find the older ebay type pumps and gauges use the older E type of symbol. At any rate 0.1 microns is the start of "hard vacuums" and what you have to get to.
It soon became clear that pressures of the order of 10-6 Torr were being reached. But the gauge’s design was attacked repeatedly. Morris Travers, who used it with Ramsay, complained that it was very sensitive to contamination by moisture.
The above quote concerns the Sprengel Pump. I suspect it suffices for a low cost experiment if and only if inlet and outlet cleaning continuously prevents unwanted intruders from entering the pump and the reactor.
One half liter can be evacuated in 20 minutes. Or should I say, it is claimed such a volume etc in twenty.
It soon became clear that pressures of the order of 10-6 Torr were being reached. But the gauge’s design was attacked repeatedly. Morris Travers, who used it with Ramsay, complained that it was very sensitive to contamination by moisture.
The above quote concerns the Sprengel Pump. I suspect it suffices for a low cost experiment if and only if inlet and outlet cleaning continuously prevents unwanted intruders from entering the pump and the reactor.
One half liter can be evacuated in 20 minutes. Or should I say, it is claimed such a volume etc in twenty.
The Pirani type gauge according to my recollection uses a heated wire that will outgas any contamination from the wire by itself, i.e. the wire bakes itself off. It is essentially a fancy conduction gauge and is limited to around 10^-4 Torr in measurement. There are better gages (ion gauges) that can go to 10^-8 Torr if you or Mizuno feel that level of clean vacuum is important, but they can't measure higher pressures. Thus if you want to go from atmospheric down to super high vacuums, you need two gauges. I think 10^-4 Torr is enough.
Last comment is that you have to correct the Pirani gauge depending on the thermal conductivity of the gas, i.e. the vacuum is different at the same measurement for H2 than D2 or He or air. The gauge is really measuring thermal conductivity and then mapped into a vacuum depending on the thermal conductivity vs pressure of the gas.
My thoughts are that the Mizuno experiment needs simply a clean environment to load with no air or water vapor left in the baked out instrument. I believe that the Pirani gauge will tell you enough at the 10^-4 Torr level or equivalent thermal conductivity for D2 gas. At those levels the number of moles left of O2 is so small that you can rule out chemical once pumped out and it should also not interfere with the D2 loading and diffusion thru the palladium/nickel metal lattices.
Someone else can comment on your Sprengel pump. However, my recollection is that the full Mizuno R20 reactor is close to 6 liters so your pump down time will be a bit longer.
The D2 will get through the Palladium filter at about 4.5 times the rate of H2. If the D2O is pure, that shouldn't matter. We don't need much D2 to operate so things should work. I put in a couple of valves to measure the amount of D2 provided. I may need a pressure gauge in the bulb to more accurately represent how much D2 was used.
Oops. I meant 1/4.5 times the rate. Obviously the D2 penetrates slower, not faster.
dartin
