Vacuum Definition and 1000 Threads

I need to perform an experiment in vacuum and would like advice on cost effective parts or how to do it. The chamber needs to be at least the size of a shoebox. Round is fine. The vacuum is required to control heat dissipation of an object as much as possible while I measure its temperature...

Hey, I'm designing an HVAC system for a laundry building. I have vacuum equipment (Vacuum press and Vacuum Ironing boards ) in the space which have a vacuum outlet the is taken outside the building through individual ducts. When all machines are operational, 877 l/s of hot air and moisture would...

I have a problem designing and understanding Wet and Dry vacuum cleaners. I understand some of the basics behind pressure however things I need to know is: what pressure/ velocity is needed to suck up water? how to calculate the pressure and velocity generated by the fan? (some examples of...

Famously em waves are an example of the latter case. The two cases (waves in a medium vs waves propagating without a medium) seem at first (to me) to be extremely different and perhaps only connected by their mathematical descriptions. I can think of two cases of waves without a medium...

What kind of ion sensor can I use in the range 1e19to 1e22 ions/m3? (corresponds to 0.1 to 5 pascals if non ionized) Does it exist any sensor based in the charge capacity?

I have a tank that is 250 Cubic Feet. The tank is under vacuum (1x10-5 Torr).. which is actually 1.93368e-7 psia. How much Argon, in cubic feet, does it take to back-fill to atmosphere or 14.7 psia? Ambient temperature in tank is 90 degrees.

Homework Statement This problem is belonging to a book, which is material for Vietnamese students who will take part in IPhO (International Physics Olympiad). Since this problem is written in Vietnamese, I will try my best to translate it to English: A vacuum diode consists of two parallel...

I read a little bit on the arrow of time and how some physicists think that it points in the direction of increasing entropy. This made sense until I thought about a vacuum. From what I read, entropy does not increase nor decrease in a vacuum so if we used this definition on the "arrow of time"...

Hello PVD experts out there ! I have question on general e-PVD Vacuum chamber cleaning maintenance and Care as shown in the pictures below, Thin film material (mostly Metals) is being deposited on a daily basis onto the hardware parts present in our e-PVD vacuum chamber ( such as the quartz...

In the 19th century Lord Kelvin made the first numerical calculation of the age of the Earth not based on the Bible.From his initial guess that the Earth started as a molten rock and that today the temperature of the interior increases at a certain rate as you approach the center, he got an age...

After some reading, I'm quite confused about the vacuum state in interacting QFT. I've read the @A. Neumaier post on "The Vacuum Fluctuation Myth," where he notes that "bare quantum field theory with a cutoff, the vacuum is a complicated multiparticle state depending on the cutoff – though in a...

If light speed (not in a vacuum) was about human walking speed ... Did any sci fi writer try that?

Hello, I'm currently taking some summer classes at my college and was assigned a project to transport vaccines from one location to another (travel time ~2-5 hours.) We have to keep the vaccine within the range of 35-46 degrees Fahrenheit at all times. My group and I came up with the idea of...

How much energy is necessary to move one kilogram of mass horizontally for one meter on a perfectly frictionless surface inside a vacuum chamber? Assuming the initial velocity of the mass is zero, the mass is at rest.

The false vacuum of the inflationary universe is described as a 'peculiar state of matter'. We know that matter density in the big bang universe dilutes as ρM ∝ a-3. Is it possible to assign a dilution rate to the 'peculiar state of matter' of the false vacuum as well?

I was just wondering (Wondering!? Stop wasting our precious time!) about clapping my hands. *Claps* It's sound energy. A little energy is released as heat. Good. This means that I have used some energy from my body. In making those two energies. Right. <<Mentor note: rant removed>> So, I am in a...

does anyone have a view on how an anti particle interacts with the Higgs field? Does it have negative mass and could that mass be greater than the associated "positive" matter particle created in vacuum space as the universe fabric extends. If true, the expansion drives the borrowing from the...

If the uncertainty in the age of the Universe is ##\Delta t## then the Uncertainty Principle implies that it has an uncertainty in its energy ##\Delta E## given by $$\Delta E \ \Delta t \sim h.\tag{1}$$ If this energy fluctuation excites the zero-point electromagnetic field of the vacuum then a...

How long would it take for a blob of mercury (the size of a marble or so) to freeze in space? I'd emagine it would have to boil in some way first, and that would send pieces of it flying around, but the surface tension of mercury is much greater than that of water, or urine (as we'd seen...

Hello. I am attempting to build a large vacuum chamber for woodworking (used to infuse wood with resin/stabilizer). I would like to use a cast iron bathtub, similar to the one pictured as the vessel. I would ideally like to use a clear acrylic lid (with a rubber gasket) like the one on my...

I have two vacuum sources each pulling 1 inHG. If I connect the vacuum sources to a Y-connector, with identical sized hoses, so that each pulls on one tip of the Y, will I get 2 inHG vacuum on the remaining hose, or will I get 1 inHG with more cfm? Thank you, B

So I am planning on launching a Satellite to promote the Dogecoin cryptocurrency. One of the main points is printing/painting (Or whatever) the logo on the side of a metal panel. How can I make it so it doesn't melt off or turn white from radiation so quickly?

There seem to be two ways of defning what a vacuum is in QFT: 1. It is state $|0\rangle$ such that $$a_k|0\rangle = 0$$ for all anihilation operators $$a_k$$, with creation operators $$a_k^{\dagger}$$. Thus, it is defined in Fock space. 2. It is state $$|0\rangle$$ such that derivative...

It has been proposed by Edward P. Tryon that the Universe may be a large scale quantum mechanical vacuum fluctuation where positive mass-energy is balanced by negative gravitational potential energy, as a consequence of the early inflationary launch of the expansion of the Universe, in which...

I was trying to log data inside a vacuum chamber, tried an arduino and a rasperry pi. When reaching -30inHg the devices just stopped working, they powered off, no data in or out and would not work ever again. Why? And no, they did not overheat.

I'm looking for a cheap, wide mouthed jar capable of withstanding moderate vacuum (up to 29-30" Hg). The jar I've currently been using is like http://packagingoptionsdirect.com/8-oz-french-square-clear-glass-bottle-028047?gclid=EAIaIQobChMIqMnmme_g2gIVgUSGCh3frw2_EAQYAyABEgKgG_D_BwE one with a...

May I know objects are allowed and prohibited to exist in the quantum vacuum as sanctioned by Witten, Hawking and others of the authority? If all the quantum fields were gone.. and we have only branes left.. do you consider branes as existing in the quantum vacuum or outside of it? Or what...

Having seen plenty of 'vacuum in a tube' tests on youtube I am wondering how a human can work in such an environment. I'm trying to understand how a space suit can be tested before it is used 'live' in space, and how seemingly 'everyday' materials are used to protect astronauts from the harsh...

given a complete vacume.(Excluding the photons) given a volume. given a temprature. given a wavelenth. work out the number of photons in the vacume?

Sorry for the vague title, I really wish the title character limit was longer. Suppose you are floating in space without gravity, but instead of a vacuum, there is air all around you. You turn on a powerful vacuum cleaner with the nozzle pointed directly ahead of you. Ignore torque/rotational...

Actually while studying the inflation phenomenon the transition of the slowly rolling scaler field from from the false vacuum to true vacuum state to a more classically stable state I actually didn't understand this transition from false vacuum to true vacuum and what actually they mean? Another...

What is the best theory why our vacuum may be in the edge of metastability? Is it possible there are many false vacuum separated by energy barriers and the reason why our vacuum may be metastable is so that it is easier to cross the different false vacua (not necessarily to the true vacuum)?

I'm talking of the virtual EM modes of vacuum...

What is the temperature of a vacuum? Could this be used as an insulator in windows/homes?

Does space have its own density? i.e. a mass density distinct from the mass density of 'particles' in it? or may it have a uniform density of some kind of vast particle(s)? If so, would the effect on observable masses largely cancel out? One answer from...

Hi. Reading some recent threads I have found basic questions about light, fields, etc. For example, why something like light, associated with the electric and magnetic fields, can exist in a vacuum. And I noticed that every time I've been asked that kind of question, I answered "how" the...

I've been searching but i can not find the answer. This is for my turbocharged car. I just fabricated a rear turbocharger at the back. Really not sure how to word this,sorry. Question 1: So my car produces 26Hg/in vacuum at the engine. About how much pressure drop per foot is expected? The...

One idea for a moon base would be reinforced concrete domes, but is pouring concrete in a total vacuum even possible? Wouldn't the water just evaporate, or is there another material we could use instead of water? Are the ingredients of concrete plentiful on the moon, or could we synthesize them...

Im trying to do some data logging, using a raspberry pi 3 would be super easy as it has a built in WiFi and Bluetooth receiver as well as an SD card. However when the vacuum gets to about -30inHg the Pi shuts off and the red light starts flashing as if there is no OS. Temperatures arent crazy...

So if string theory is to be correct it must be able to come up with the observed value for the energy density of empty space which is pretty close to zero? A naive understanding of the compact spaces of string theory tells me that an "energy audit" of the highly curved compact manifolds of...

This is what I understand about light. Light is electromagnetic wave, it comes from the source, bounces from the objects and we see reflected light. Let's imagine next situation. We are in a dark room and we got only one light source, a toy laser. When we turn it on, we can clearly see beam...

According to [Dark Energy and the Accelerating Universe](https://ned.ipac.caltech.edu/level5/March08/Frieman/Frieman5.html) quantum field theory says that the energy density of the vacuum, ##\rho_{vac}##, should be given by $$\rho_{vac}=\frac{1}{2}\sum_{\rm...

Hey I'm new to Physics. I have a question. Is it possible to use the force generated when air entera a vacuum tube to launch something into space? Can anybody throw some light on this in simple words please. Thank You.

I'm writing a serialized Steampunk-fantasy story in which the cities float high in the planet's atmosphere using a combination of Magic and technology (sci-fi-ish steampunk technology) Though I want to bring it as close to real science as I can. From some google searches it seems that a vacuum...

Hey guys, I have been scouring the internet to find an answer but I can not. The problem is: I want to heat water to boiling point with the least amount of energy required. I found out that if you apply vacuum into an chamber with water (room temp), the boiling point can be as low as room...

I'm writing a novel and wanted to research a possible weapon I came up with to make sure the physics are at least possible. However, I could not find anything on vacuum-based projectiles other than ping-pong balls, while this is interesting, but it doesn't answer my question on what would happen...

If the universe suffered a false vacuum decay, would this change physical laws? Could it change the universe so much that it would allow our universe to be a multiverse of level 1, 2, 3 and 4? https://en.wikipedia.org/wiki/Multiverse

From the basic definition of vacuum energy as being tied in with the Uncertainty principle, I would expect this not to include the Cosmic Background Radiation. Right? On the other hand, in figuring out (a) the Casimir effect, one attributes the force to the field between the plates carrying...

If mass of a particle is less than the vacuum energy density.. what would happen.. is this possible (also for some dark matter species)? How about photons.. are they more or less than the vacuum energy density? And what exactly is the value of vacuum energy density?

I've been doing a little bit of reading on string theory, and the very large number of string vacua that are possible (i.e., perhaps 10^500 or more). One thing that is not clear to me is exactly what constitutes a 'vacuum' in string theory. In QFT theory, the vacuum is defined as the state with...