Looking forward to the day when FreeCAD is a viable and stable option for free parametric CAD. There are a few free options for direct modeling, but not for parametric design.
As far as commercial software goes, my current favorite CAD software for hobby use is Rhino[1]. It's not parametric[2], but it's stable, fast[3], can import and export a wide variety of 3D file types, and it's pay-once-per-major-release. It's not cloud-based. The marketing around it seems to emphasize design/architecture/artistic use cases, but it also works well for dimensionally-accurate mechanical parts.
For those eligible for a student license, the pricing is reasonable (cheaper still if you shop around among third-party edu software vendors). Surprisingly, the student license also allows commercial use.
For anyone with a UDMP looking to disable remote access via UniFi servers, the setting isn't under the Network application, it's part of the higher level console management:
And note that to see the Remote Access checkbox, you need to be logged into the console as a ui.com user, not a local user.
If you have disabled Remote Access and instead want to use the phone app via a VPN, you may have to add it manually. There's a (+) button for that, and then a "Need help?" option, which contains a way to manually add by IP/user/password.
I wonder if a pump like this could be made smaller using a perfluorocarbon liquid like FC-70 (Perfluorotripentylamine)—nearly double the density of water, higher boiling point, non-flammable, and would not impart water vapor to the compressed air.
I wouldn't necessarily be able to say whether it'd be smaller, but it'd probably work. It works due to the air getting entrained in the liquid as it increases in pressure. So there shouldn't be a requirement that the air dissolve into the fluid or anything like that.
The Apple Store sells both and will let you compare the two models if you ask nicely (with new/clean AirPods). I found AirPods have noticeably better noise cancellation (for me) than the QC35s, but YMMV. Subtle but better. It's hard to say if my impression was due to better passive noise isolation or improved active noise cancellation (does the QC35 have an error-correction microphone downstream?). One thing that is absolutely true is that the QC35s do not work as well mechanically for those of us who wear eyeglasses: the cushions can't seal around the temple pieces of the frames, so some sound will always leak under the eyeglasses. For that reason alone—even if the AirPods have equivalent noise cancellation tech—the AirPods can work better for people with glasses as long as the tips seal properly. My wife, an eyeglass wearer with long hair, also found the AirPods more effective at reducing noise when we tried them both at the Apple Store. I certainly find them effective for commuter rail travel.
As an aside, one slightly annoying usability issue with the AirPods is that in comparison to the QC35 they behave differently when part of a multi-output audio device under MacOS. My wife and I often watch video using two pairs of bluetooth headphones paired and synced to the same Macbook Pro[1,2]. It's great for late-night movies in city apartments. Using the QC35s and her headphones, the aggregate device remains selected when the QC35s are paused or turned off (meaning, she can still listen if I go out of range or turn off my headphones). With the AirPods, if I take one out of my ear (to scratch an itch, say), the AirPods suddenly become the only audio output device when I put it back in, and the second pair of headphones goes silent. A small annoyance, but curious.
Indeed; a good library is a long-tail institution. The Harvard Library system has a large collection of books at the various on-campus libraries, but an immense catalog of infrequently accessed books at a "depository" warehouse off-site. Scholars can request items from the Depository and receive them within a day.
This split-storage model may a sensible solution for other universities going forward: prime and expensive library buildings on-campus can be reserved for quiet study areas and a few commonly-used books, with the main collection of books retrievable from a nearby location where land is less expensive. It also has the advantage of allowing books to be stored in the ideal climate for their preservation.
Fun fact about the Harvard Depository: books are organized not by topic, publication date, or anything resembling the Dewey decimal system, but rather by a metric that makes sense for high-density: physical size. Books are stored in barcoded boxes by height. Here is an artsy documentary, "Cold Storage," about the Depository:
Pretty much every library has an off campus facility for books. USC has a warehouse on grand avenue. Not sure where UCLA's book repository is, but it is definitely somewhere.
However, I wouldn't want the stacks in the main library (doheny) at usc converted to study space. I think there are better rooms to gut for study space, namely the random faculty offices they've shoved in every library. You can build an office across the street from campus if you need the space. The ceiling in the stacks is maybe 6.5' tall, it's musty and the HVAC is deafening, and extends 6 stories down into the earth. I couldn't imagine a more disheartening study environment, but there are some tables and chairs and sad graduate students down there nonetheless.
The coolest solution I've read about to note the producer is to emboss a hologram in the metal, though perhaps with enough care this too could be faked or copied:
The coolest solution I heard was to look at a well defined spot of the gold bar and register the impurities/bubbles/structure that naturally happen while casting. This is very difficult to reproduce (because there is no legitimate need to do so) and is already present.
There are other methods like this, Sunshine Minting for example has a 'decoding lens' for their products that contain the 'MintMark SI security feature'.
Geiger Edelmetalle , on their Geiger branded stuff, uses a a UV safety coating but it will rub off with enough handling (which is why many of us do not remove the shrink wrap they put on their bars), they also individually assign serial numbers that can be tracked online for gold and silver bars starting at 1 gram
Helpful tip, thanks. Here's the Safety Data Sheet (SDS) in case anyone is curious what's in 3M 38983 General Purpose Adhesive Remover[1]: Mostly methyl acetate, with some naptha, xylene, and a small amount of ethylbenzene. Definitely worth heeding the precautionary statements...
For contrast, "Goo Gone" is mostly naptha-like light petroleum distillate with small fractions of limonene and orange extract[2].
3M adhesive remover will not remove paint. I used gallons on cars to remove plastidip. It says right on the container, safe for car paint and clear coat. Advertised to remove bumper stickers.
Yeah it worth trying Goo Gone first and reserve this for the really tough adhesives. There can’t be many laptop stickers that can’t be removed with Goo Gone plus patience (which BTW also works wonders for removing road tar from car paint).
Hot water "hydronic" heating with radiators is very common in the US as well, at least among homes in the Northeastern US constructed before the 1960s. It's a shame more new construction does not use hot water heating in conjunction with central air for cooling because radiators are much quieter, more efficient, and better for those with asthma.
I live in a house with steam heat. Steam systems often get converted to hot water, but in general I have a few observations related to radiated heat.
1) Steam and other radiant systems don't deal with temperature setbacks well. They take FOREVER to warm up a house after a set back, so don't bother with a deep setback overnight, and if you are gonna turn down the heat because you are going to be gone for a while, expect your house to be cold for a couple of hours while it warms back up, or expect your heat to overshoot by 5-10 degrees.
2) Radiant heat seems to work well in the temperature range it is designed for, but outside of that range you get strong temperature gradients in rooms. Unless you have a fan in each room, expect the ceiling to be substantially warmer than the floor. I have 12 foot ceilings, and the ceiling can be 15 - 20 degrees warmer.
3) I personally prefer forced air with my allergies than radiant heat, because you can upgrade a forced-air system to use better filters, which basically gives you a filter for your entire house. Radiators are a pain in the ass to keep clean, and the air often seems to go stale over time. I have fairly bad indoor allergies and it just feels like over winter the house just fills with allergens.
4) On the same note, you can't get whole-house humidifiers with steam heat, nor can you easily add air conditioning.
5) Steam isn't THAT quiet. An improperly tuned system will bang (which shouldn't count against steam, because that's the fault of whoever is maintaining the system), one-pipe systems (which are common in Chicago) hiss when they are heating up, the valves sputter as they die, and when the system cools back down there is a loud inrush of air. Two pipe systems make noise as they heat up and joints flex, and the valves also make little clicking sounds.
Hot water can get bubbles in it and make wooshing sounds, but that's generally a sign of bad maintenance.
The sound of air blowing bothers me less in general than one off sounds that occur with steam and hot water though, and unless you don't mind the aforementioned temperature gradients you'll need to have a fan running anyways.
6) It's much much easier to find people who know how to work on forced air in the US. Replacement parts are easier to find, and forced air is usually more efficient.
One big benefit to steam is that old systems were massively oversized for the houses they are in. My house had absolutely NO problem getting up to temp during the week we had below zero temps. It was running a lot though, and the leaking shutoff valves and blurbling air vents were starting to drive me nuts, so I shut off the heat for a couple of hours on the coldest day (which got down to -40 or so) to do repairs. It got down to about 40 degrees inside before I turned the heat back on, and once it was back on it got up to 70 or so no problem. I know a lot of people who had more modern systems that struggled to maintain 40 or 50 degrees.
Side note: If anyone has a steam heat system in their home, I would highly recommend picking up The Lost Art of Steam Heating by Dan Holohan. As I mentioned, it's hard to find a real steam heating expert nowadays, most of the time you'll just get plumbers who are moonlighting. While steam heat involves plugging pipes together, there are a lot more things to take into account other than whether pipe A and pipe B are connected.
> you can upgrade a forced-air system to use better filters, which basically gives you a filter for your entire house.
This is a reason I really like our forced air system (New England house from the 50s): it can circulate and filter the air even without heating or cooling it. I have it run hourly for part of the day and it does wonders to keep the air fresh (i.e. we really notice when the system is off for some reason).
> They take FOREVER to warm up a house after a set back, so don't bother with a deep setback overnight
This is incredibly true in intermittently occupied areas. Just heating the air is one thing. Heating everything around it just to get warm is another.
If you're in a private/semi-private office 9-5, having your own heater or window A/C gives you a lot of control and is incredibly efficient since you can turn it on/off with your work hours.
It will cycle a lot because the envelope doesn't change temperature much (eventually heating/cooling the air), but you reduce consumption a lot by not getting to the point of majorly heating/cooling the envelope, just the air (which is what matters unless a mattress is involved).
Yeah, exactly. I like to have it relatively cold at night, so with forced air I set the heat to come on about 15-20 minutes before I want to get out of bed, and turn off 15 minutes after I leave for the day.
With radiant heat, if I want it to be 55 while I'm sleeping, and 70 when I leave my bed, my heat will come on 2 hours before I'm going to get up, and the temperature will slowly increase over that time, leading to it being far too warm about an hour before I intend to get up. The heater turns off as the house gets up to temp, but the radiators thermal mass is such that they are still quite hot when I leave for the day, in effect heating the house long after I've left.
Furthermore, it's basically impossible to have zone heat with one-pipe systems, and it's much more difficult with two pipe systems. (This is less of a problem with hot water though).
With forced air, you can install active vents fairly easily, and while you still can't cut off TOO many of the vents at once, lest you cause too much back-pressure in the system, it is fairly easy to heat one side of your house or one floor of your house.
On top of all that, steam doesn't handle short-cycling well, so you have to accept a wider swing in temp than you do with forced air.
Significantly overshooting the temp is something you can avoid. The thermostat needs more information, but predicting the temperature in 10 minutes if the heat is turned off now is not that complex.
Then you can have fully functioning heat even when the power is out, because the steam does not need either a blower or a circulator pump to circulate, and the thermocouple provides the electricity to operate the thermostat and the gas valve.
Even without a millivolt system, a small UPS can run the little low voltage transformer a long time, while it would take an impractical amount of battery (which will crap out in only 3-4 years) to run a blower or circulator for any length of time.
Your points are all valid, and frankly outweigh this one except maybe at a vacation/camp house or something way out where the electric is bad, but this is something nothing else can claim.
It is pretty nice that when the ice storm pulls the power lines down, and, because it's an ice storm and it affected entire states all at the same time, your power may stay down for days, and does so coincidentally in the winter...your heat just keeps working even if nothing else does, and indefinitely not just until a 45 minute ups runs out.
Also... everyone with steam, replace your pressurtrol with a vaporstat and run your system at much lower pressure than it's probably set at. 1/2 psi per floor not counting basement, at most.
> They take FOREVER to warm up a house after a set back, so don't bother with a deep setback overnight
Steam and other radiant systems don't deal with temperature setbacks well. In the UK and Ireland people perform a deep setback (on their hot water system) overnight then usually just accept that the house will be cold in the mornings.
As far as commercial software goes, my current favorite CAD software for hobby use is Rhino[1]. It's not parametric[2], but it's stable, fast[3], can import and export a wide variety of 3D file types, and it's pay-once-per-major-release. It's not cloud-based. The marketing around it seems to emphasize design/architecture/artistic use cases, but it also works well for dimensionally-accurate mechanical parts.
For those eligible for a student license, the pricing is reasonable (cheaper still if you shop around among third-party edu software vendors). Surprisingly, the student license also allows commercial use.
1. https://www.rhino3d.com
2. Well, Rhino is not parametric in the usual sketch-based way. People do wild things with the Grasshopper plugin.
3. Rhino also runs on macOS, w/ hardware acceleration of graphics via Metal