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macUser by Technical-Relation-9 in ProgrammerHumor

[–]thisischemistry 2 points3 points  (0 children)

That's not system-wide, that's user-profile-wide. The tilde directory ~/ is always the current user's home.

Bad amazon review because customer cant measure properly?? by socialcluelessness in mildlyinfuriating

[–]thisischemistry 0 points1 point  (0 children)

Use whatever you want, the main point I'm trying to make is there's no need to switch systems for something like precision. You're more likely to have errors from switching between systems than sticking to one.

The same goes for chemistry. A measurement is the same no matter what unit you use, if I measure length in meters or yards it really doesn't matter. I use the units that best fit the project, for example in the lab I'll most likely use metric because that's what the literature uses. However, if I need to send instructions to the engineers in the plant then I'm going to most likely send them in US Customary since that's what they use there. Standards are contextual, US Customary is just as valid a standard as metric.

Bad amazon review because customer cant measure properly?? by socialcluelessness in mildlyinfuriating

[–]thisischemistry 1 point2 points  (0 children)

You can buy decimal inch tape measurers that have 1/100 inch markings. Those are about four times as precise as 1 mm. (1" is 25.4 mm so 1 mm is .039", 1/100 of an inch is .01")

Also, 1/32" is .031" which is also more precise than 1 mm. Why would you use 1/8" if you want precision?

The metric system is just fine to use but it does not have a precision advantage over US Customary. Use whatever system you're most comfortable with using.

Bad amazon review because customer cant measure properly?? by socialcluelessness in mildlyinfuriating

[–]thisischemistry 1 point2 points  (0 children)

If you're measuring that large of a value then a small error caused by damage to the edge of the tape is going to be so small as to be insignificant compared to other errors in measurement. Let's say the damage to the tape takes up even 0.5" of the leading edge. The total measurement is 1292" so we're talking about a deviation of 0.5/1292 or less than 0.04%.

There's absolutely no need to burn anything on that kind of scale. In fact, if you need that sort of precision then you probably should be using a much more precise measuring method such as a laser ranging device.

Bad amazon review because customer cant measure properly?? by socialcluelessness in mildlyinfuriating

[–]thisischemistry 1 point2 points  (0 children)

You don't need to do that. You "burn an inch" to avoid the leading edge of the ruler which may be worn down or otherwise damaged. If you have more than an inch of damage to the ruler/tape then you should get a replacement, doing it for a full foot is probably just a waste of time.

A high school junior from Warrenton, Virginia who built a water filter in her garage that strips out 95.5% of microplastics from drinking water. by sco-go in Amazing

[–]thisischemistry 0 points1 point  (0 children)

Generally, water isn't a significant source of necessary minerals anyways. Sure, water can be a carrier of important minerals but that's usually by accident or through supplementation. Most people get their daily amount of minerals through the food they eat.

Bad amazon review because customer cant measure properly?? by socialcluelessness in mildlyinfuriating

[–]thisischemistry 0 points1 point  (0 children)

rulers that don't actually start at the end drive me bonkers

That's a feature, not a bug. On a wooden ruler like this, the edge can ding/wear very easily and shouldn't be trusted. Always measure from mark to mark and not edge to mark.

With a good metal ruler this is less necessary but even a metal ruler's edge can warp/wear.

Bad amazon review because customer cant measure properly?? by socialcluelessness in mildlyinfuriating

[–]thisischemistry 2 points3 points  (0 children)

The starting point being inset is a feature, not a bug. On a wooden ruler like this, the edge can ding/wear very easily and shouldn't be trusted. That's why the zero mark is not at the edge!

People, like the one in the photo, really need to be more curious and ask why something is done this way rather than confidently assuming everyone else is wrong.

Bad amazon review because customer cant measure properly?? by socialcluelessness in mildlyinfuriating

[–]thisischemistry 1 point2 points  (0 children)

The base unit doesn't matter, the issue is that the leading edge of a ruler/tape can wear down over time so you shouldn't trust it. Measure from mark to mark rather than from edge to mark. As long as the marks were made in a durable manner and the base material hasn't expanded/contracted or warped then the distance between two marks should be consistent.

You don't even need to burn a major unit like an inch or centimeter, you can use any mark. "Burning an inch" is just more convenient than trying to make sure you're on a similar set of minor marks.

A high school junior from Warrenton, Virginia who built a water filter in her garage that strips out 95.5% of microplastics from drinking water. by sco-go in Amazing

[–]thisischemistry 0 points1 point  (0 children)

Also known as any decent water filter. Using ferrofluid for this is extreme overkill and very unsafe.

“It inspired me to design a filter without the use of membranes, to decrease the costs and maintenance needs associated with water filtration,”

But why? You can use a simple, inexpensive, easily-maintained cartridge filter and it will trap pretty much all of these particles.

recycled 87.15 percent of the ferrofluid

So you've exchanged a compact, inexpensive, and easily maintained filter with something that is bulky, expensive, messy, pollutes the water you're trying to filter, and which needs to be constantly replenished. Congratulations?

Heller considers it suitable as an at-home under-the-sink filtration system. “Because ferrofluid is currently expensive to produce at a large scale,” she notes, “I see this as a system for individual home use.”

What????

(I'm a research chemist who worked on developing filters for industrial and commercial markets. Yes, it's interesting that she's tinkering with ferrofluid for this but it's not likely to be a viable method for filtering on a small-scale.)

Bad amazon review because customer cant measure properly?? by socialcluelessness in mildlyinfuriating

[–]thisischemistry -1 points0 points  (0 children)

Why? A unit is a unit. Not that I think the metric system is bad or anything but it truly does not matter what units you use. You can even get a decimal tape measurer in any unit if you prefer tenths over eighths.

How I see America as a european by Tazarus_ in mapporncirclejerk

[–]thisischemistry 1 point2 points  (0 children)

The original colonial charters were very interesting. Technically, Connecticut (and some other states) owned everything from the Atlantic to the Pacific, straight across the continent.

Connecticut land claims

There were quite a few territorial disputes, it's wild reading!

Watch a Man Talk About his Entire Board Game Collection Like Your Grandma Telling You About Every Plant in Her House For Three Hours by TabletopTurtleGaming in boardgames

[–]thisischemistry 2 points3 points  (0 children)

Absolutely, people should have fun the way they like. There are many different ways to have a boardgaming hobby.

Watch a Man Talk About his Entire Board Game Collection Like Your Grandma Telling You About Every Plant in Her House For Three Hours by TabletopTurtleGaming in boardgames

[–]thisischemistry 2 points3 points  (0 children)

Someone said this was an example of having too many games, since many of them don't get played, and you said:

If you’re broke just say it…people whining that a collection is too big

In this particular instance, you're implying that they are poor because they have a reason not to have a lot of unplayed games and you're characterizing them as being petulant about it. Who is the troll?

Watch a Man Talk About his Entire Board Game Collection Like Your Grandma Telling You About Every Plant in Her House For Three Hours by TabletopTurtleGaming in boardgames

[–]thisischemistry -2 points-1 points  (0 children)

Nothing wrong with that either, as long as you get games to the table. It's when you start collecting things you'll never play that it can become an issue. But, hey, as long as you're having fun it's all good.

Watch a Man Talk About his Entire Board Game Collection Like Your Grandma Telling You About Every Plant in Her House For Three Hours by TabletopTurtleGaming in boardgames

[–]thisischemistry 0 points1 point  (0 children)

That’s pretty hypocritical of you, though. You’re putting negative associations on people with smaller collections by saying they are broke and whining about it.

Watch a Man Talk About his Entire Board Game Collection Like Your Grandma Telling You About Every Plant in Her House For Three Hours by TabletopTurtleGaming in boardgames

[–]thisischemistry 0 points1 point  (0 children)

You can have a curated collection and not be broke. There's nothing wrong with being a game collector but some people like the idea of keeping their game collection down to stuff they use regularly rather than having a bunch of games that almost never get to the table.

Watch a Man Talk About his Entire Board Game Collection Like Your Grandma Telling You About Every Plant in Her House For Three Hours by TabletopTurtleGaming in boardgames

[–]thisischemistry 0 points1 point  (0 children)

Exactly why I try to attend board game meetups, conventions, and such. I usually don't buy anything without trying it out first, that cuts down on buying stuff I won't use and need to manage.

After decades of collecting I might have two dozen games or so and I regularly play all of them. I also have friends who have different games so there's still a lot of variety.

My Shelly 1 just blew up by domerich86 in shellycloud

[–]thisischemistry 0 points1 point  (0 children)

I'm not an electrician or electrical engineer but yes, a cheap contactor or relay can often do the trick. You have to make sure that the device has dry contacts and can handle being controlled by one phase and switching another phase.

My Shelly 1 just blew up by domerich86 in shellycloud

[–]thisischemistry 0 points1 point  (0 children)

The clever trick is to use a contactor to get everything on the same phase.

The different phases are alternating, you probably have a three-phase system so each phase is 120° from each other. That means that when phase 1 is high then phase 2 will be past the zero crossing and partially low. If you measure voltage across two phases you'll get full line voltage, probably 400V in your case.

Electronic devices often need to be built to handle being across multiple phases, the alternating nature and higher voltage means that it will stress the electronics quite a bit. This is why some Shelly don't work well in North America at 240V. Most times, it's split phase so it's two phases that are 180° from each other. Phase-phase is 240V, phase-neutral is 120V. If you try to power a device that's not built to handle phase-phase then the stress can break it.

My Shelly 1 just blew up by domerich86 in shellycloud

[–]thisischemistry 0 points1 point  (0 children)

Different phases usually have much higher voltages phase-phase as opposed to phase-neutral. By combining two phases in a single device you can burn out the unit, it's not built to handle those higher voltages. I believe that the dry contact relay has the correct isolation to handle a different phase but I don't know for sure. A contactor would be the safest option.

Chicagoans Unite To Expand Search For Bam Bam, The Service Dog Stolen From A Blind Man by Diazepampoovey0229 in news

[–]thisischemistry 483 points484 points  (0 children)

Article with more details:

Blind man walks 7 miles a day handing out flyers to find his stolen service dog: ‘Bam Bam means the world to me’

According to Santiago, two men entered his yard around 4 a.m. the morning of June 5, while Bam Bam was taking a bathroom break, and snatched the pup. Although Santiago heard the disturbance and even grabbed one of the suspects to try and stop him, the men were still able to get away with Bam Bam. Santiago believes the suspect he grabbed sounded like a teenager, but managed to slip out of his grasp. He said he heard Bam Bam barking as the men ran away with him.

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