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    I need a pressure regulator, but I don't know what kind?

    I want to be able to control the pressure of air in a small, closed environment. The closed volume is no more than 250 ml, or a cup. I have a 100 psi air source available and I want to be able to adjust the pressure in the closed environment within the range of 0 - 45 psi. It is not necessary for me to know the true pressure (though that would be useful).

    I don't know what sort of pressure stability to ask for. It will depend on how much more expensive +/- 1 psi vs +/- 0.1 psi is. Any electronics should be self-contained. A computer connection may provided, but must not be mandatory

    What sort of a regulator am I looking for?

    9 AnswersEngineering2 months ago
  • Which version of Surface Pro do I have?

    My computer tells me that it is a Surface Pro i7 Model 1796

    Is this a Surface Pro 5, a Surface Pro 6, or what?

    I have cracked my computer's screen and need to buy a replacement, but I don't know which display to buy

    1 AnswerLaptops & Notebooks3 months ago
  • Milling at non-optimal rates?

    I'm new to milling. I want to mill some brass, which should be very easy, but at 2000 sfm, and a 1/2" mill, I get over 15000 rpm. My machine can't get close to that. I'm using manual feed too.

    What is the down side of milling material at a speed considerably slower than the optimum removal rate?

    Hobbies & Crafts9 months ago
  • Why does anhydrite drill slowly?

    Anhydrite is a very soft rock, yet it drills much slower than carbonates. I have seen 15 min/ft drill times.It seems like the drill bits should just chew right through it, but clearly they don't. Why?

    1 AnswerEarth Sciences & Geology11 months ago
  • Adding gauge to vacuum desiccator?

    I have a large glass vacuum desiccator that has a 24/29 ground glass fitting at the top. I would like to put a vacuum gauge on the desiccator side of the vacuum shutoff valve.

    How is a gauge stem connected to the glassware? I'm not sure what sort of hardware I'm looking for. Is some sort of threaded connection available? Is it done with an o-ring seal? How can I connect a gauge into my system?

    2 AnswersChemistry1 year ago
  • Is there language in the U.S. Constitution or other legislation that prohibits fomenting rebellion or civil war?

    Not actually participating in the act of rebellion or war, just promoting and inciting it.

    The Sedition Act covers some. What else is there?

    2 AnswersLaw & Ethics1 year ago
  • Molding a long, flat object?

    I want to cast a long, thin part in hard urethane (80D) for prototyping. The part will be about 33" long, about 5" wide and about 1/2" thick and is a long radius arc of a circle, as though you have cut a sector from a disc.

    It is intended that the upper and lower surfaces of the part will be rolling surfaces. The lower surface is supported atop some transfer ball casters and a second piece can be rolled along the upper surface. Therefore, I want the upper and lower surfaces to pretty flat and straight.

    1) Is molding an appropriate method for what I want or should I be looking at a different process?

    2) Would a silicone mold, with a support structure to maintain rigidity, be sufficient as a mold? How do you suggest maintaining straightness and flatness?

    3) How do I fill the mold?

    Do I create a two part mold, tilt it a bit and fill by injecting from the lowest point? Is there a way to fill the open mold and lay the second portion in place without making a giant mess? How would you actually make this part?

    I do have vacuum equipment suitable for de-airing. Any tips relating to mold release, etc. would be appreciated


    2 AnswersEngineering2 years ago
  • What is an iPhone Activation Lock and why would one appear on my phone?

    I had been using my phone earlier in the day. Battery was getting low (but not seriously low) so I plugged it in. A few hours later, I picked up my phone to text a friend and there is an Activation Lock on my phone, and it wants me to enter my iCloud login credentials.

    To me this looks like a classic Trojan. But could it just be a glitch in the system? Or could it be legitimate? What triggers an Activation Lock? I think the first message I read might have said something about an attempt to use Find My iPhone

    1 AnswerCell Phones & Plans2 years ago
  • Mac terminal command syntax?

    I need to go to Mac Terminal to get something done. The command refers to an application file name that includes both a space and a decimal. The app file name is


    My Unix experience has a lot of dust on it. I can make the command succeed if I simply rename the app to FireCapture, but I would prefer to keep the version information. Will wrapping the app name in quotes work like this?

    command "FireCapture"

    Is there a better way to do this?

    2 AnswersSoftware2 years ago
  • Attachment image

    Need help with Mac terminal commands?

    My Unix days are long, long ago. The goal here is to get Gatekeeper to allow an app to run. Please refer to the photo.


    At Step 1, I ask for a listing of Desktop to verify that the app that I want to allow, FireCapture v2.6, is present.

    At Step 2, I issue a command to Gatekeeper to add the exception. It fails.

    At Step 3, I issue the same command as a superuser. The command fails.

    After Step 3, but before Step 4, I rename FireCapture to You can see the Finder is showing the name of the app as

    At Step 4 I issue the same command as Step 3 and it works. Subsequent testing of the app verifies that Gatekeeper now allows the app to launch.

    Question 1:

    Why did the commands fail when the app name was FireCapture, but succeeded when the name was changed to

    Question 2:

    Was it necessary to issue the command as superuser once I had the name fixed or would the command have worked without the sudo?

    2 AnswersSoftware2 years ago
  • Numerical values in TIFF files?

    Why are numerical values in monochrome TIFF files different from those in RGB TIFF files?

    1 AnswerSoftware3 years ago
  • What fact check site do conservatives trust?

    I'm not trolling here. I know that they don't like Snopes because, well the Mikkelsons are from California, so they'er obviously liberals.

    So, if Snopes is unacceptable and I want to let one of my conservative friends know that no one is putting HIV infected needles in gas pump handles, that it's an old scare going back to when there were pay phones and people supposedly put HIV infected needles in the coin returns, who can I send them to that they will actually trust the source.

    17 AnswersPolitics3 years ago
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    What famous (possibly infamous) Chicogoan?

    died in the summer of 1957 - 59 or maybe 1960. The person died someplace else and was returned to Chicago for services. Whoever it was, had enough significance that it warranted a police escort, and people lined the road taking pictures of the hearse as it left the airport

    3 AnswersHistory3 years ago
  • Hydrogen alpha imaging with a high megapixel color sensor vs a dedicated monochrome camera?

    I have a Sony Alpha7R Mk2 DSLR which produces 42 Mpix images. Given that only one in 4 pixels is going to see anything in a Ha image, that cuts my resolution by a factor of 4 resulting in effectively a 10 Mpix image. The highest resolution I see on the monochrome cameras is about 5 Mpix. Am I better off using 1/4 of the pixels of a Bayer filtered sensor that has 42 Mpix or does a lower pixel count monochrome camera still have other advantages?

  • Comments on this telescope please?

    I am interested in getting an entry level telescope with the primary goals of lunar and planetary viewing (as opposed to deep space objects). I have a good bit of experience with photography and microscopy. The Celestron Advanced VX 8" EdgeHD appears to be about the level that I am looking for with a decent, but not huge aperture, Go To system, and reasonable portability.

    I have both Nikon and Sony full frame cameras for image capture.

    Would you recommend a different scope (somewhere near this price point)?

    What accessories do you consider indispensible?

    I plan to use the scope to observe the eclipse. Aside from the necessary neutral density filter and suitable eye protection for myself, is there anything else I would need?

    3 AnswersAstronomy & Space3 years ago
  • Telescope for general viewing plus solar?

    For many years I have been interested in astronomy, but made a decision a good while back to go the direction of microscopy rather than getting a telescope. With the upcoming total eclipse, I have a new impetus to my astronomy urges. But I don't want to buy a dedicated solar scope, at least I don't think so. After the eclipse, I would like to use the scope for more traditional stuff - moon, planets, nebulae...

    I am at the point in life where I can afford some decent optics. A four figure price tag isn't too much, though I need to question how much I'll really be using it if we start talking 5 figures.

    What sort of system should I be looking at? Am I seriously hobbling my eclipse viewing by relying on add-on filters for a traditional scope? Is an internal doppler etalon essential for a good hydrogen alpha image (this feature seems to be emphasized in the dedicated solar scopes)? What add-on filters would be most useful for the eclipse?

    It's probably another discussion altogether, but do you have any recommendations for automated trackers to accommodate for Earth rotation?

    1 AnswerAstronomy & Space3 years ago
  • Firing a howitzer?

    I have an old picture of my father's artillery unit. One shows a soldier about to fire the weapon and it's obvious that he is yelling something. OK, so maybe it's "Fire!" But is that what someone in the military would actually say?

    What is the name of the cord that is pulled to fire a howitzer?

    What would a soldier yell just before pulling it?

    2 AnswersMilitary4 years ago
  • When do I need a Windows partition on a Mac?

    If I get a Mac computer, under what circumstances do I need a Windows partition on my disk to support Windows programs? I have some third party programs that are not supported for a Mac. When does Windows emulation work and when doesn't it?

    One program in particular that I'm concerned about uses TCP/IP and Jumbo Frames to communicate on Ethernet. I'm not sure what sort of device drivers it might be using.

    How can I tell if program will work under Windows emulation?

    2 AnswersSoftware4 years ago