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Apr 30, 2024 02:21
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| # ? May 17, 2024 14:49 |
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I opened a beer can that had been bouncing around in my bag and had a weird train of thought, from a really dumb question to one or two that aren't so dumb. So the first, dumbest question I think I already got: Why does the beer do that, is it because the gas pocket gets sloshed around and exacerbates the carbonation somehow? If you could completely fill the can would the liquid even be able to slosh around in itself and prevent fizzing? Well no, right? Because the beer is already carbonated on its own. But that got me thinking of fluid dynamics, I guess. Liquids cannot be compressed but gases can, right? So yeah, that second question again but about a theoretical container whose entire volume is 100% absolutely full of some inert fluid like water, what's going on in there when the container is moved around? Molecules will certainly be moving about but would there be any momentum to it, like the sloshing when you shake a half-full bottle of something? That all sounds very dumb and yes I was (and am) high but it ended up in a more general question about using fluids to do work: Why do we use both hydraulic and pneumatic systems, and in what situations are either more appropriate?
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Apr 30, 2024 02:34
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Liquids are essentially noncompressible meaning that you can push on a certain volume of liquid and you will move that volume at the other end. This is useful when you’re trying to generate mechanical advantage in a compact way by pushing fluid into a very wide cylinder for example. If the system leaks though it’s a huge pain. Pneumatics are more useful when some cushioning is nice and when leaks would be pretty problematic, but they are really much more niche than hydraulics.
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Apr 30, 2024 02:57
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Mister Speaker posted:I opened a beer can that had been bouncing around in my bag and had a weird train of thought, from a really dumb question to one or two that aren't so dumb. Avoiding any gas space would be hard to do. The solubility of gases in liquids depends on temperature (more gas dissolves when cold) and pressure (more gas dissolves under higher pressure). The cans are filled with very cold liquid and high CO2 pressures. Even if you completely filled it with liquid initially, some gas would come out of solution if it warmed up at all. But if you did manage no/little gas space so that there were no tiny bubbles when you shook it, it wouldn't explode if you opened it afterwards Mister Speaker posted:But that got me thinking of fluid dynamics, I guess. Liquids cannot be compressed but gases can, right? So yeah, that second question again but about a theoretical container whose entire volume is 100% absolutely full of some inert fluid like water, what's going on in there when the container is moved around? Molecules will certainly be moving about but would there be any momentum to it, like the sloshing when you shake a half-full bottle of something?  ) if you had a completely full water bottle and then added a drop of food coloring, then capped it. The color will slowly diffuse through it, and if you shake it, it will spread faster.Mister Speaker posted:But that got me thinking of fluid dynamics, I guess. Liquids cannot be compressed but gases can, right? So yeah, that second question again but about a theoretical container whose entire volume is 100% That all sounds very dumb and yes I was (and am) high but it ended up in a more general question about using fluids to do work: Why do we use both hydraulic and pneumatic systems, and in what situations are either more appropriate? The main advantage for hydraulics is that it's much easier to make a high pressure pump for incompressible fluids, so you can have a much higher working pressure and transfer more power more easily. 10,000psi working pressure is common in hydraulic systems, pneumatics are more typically around 70-100
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Apr 30, 2024 03:47
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I was once working on improving a process that was intended to fill a container almost air free with a liquid. We improved it to reduce the air volume by orders of magnitude. Then someone picked up the prototype from the bench, and the change in temperature made it explode. The air bubble was buffering it previously
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Apr 30, 2024 12:28
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A Concorde plane went down because a piece of debris on the runway hit the fuel tank that was filled to the brim, which turned out to be a major factor in it rupturing.
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Apr 30, 2024 13:26
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VictualSquid posted:I was once working on improving a process that was intended to fill a container almost air free with a liquid. We improved it to reduce the air volume by orders of magnitude. This sounds like a marketing refocusing problem though. Sure, the storage and transportation is difficult, but imagine putting out a six pack which explodes at parties
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Apr 30, 2024 14:35
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I have a squat rack and separate standalone bench at home. It's all sitting on hard rubber floor tiles. When doing bench press or other rack exercises I prefer to have the bench positioned reasonably close to the exact middle and reasonably square. Eyeballing isn't enough for me to always get it close enough on the first try without an annoying amount of effort. What's the best way to quickly align the bench each time? Generally I've been making marks on the rubber flooring, but the methods have disadvantages. Chalk works great but it wears off quickly with the foot traffic, I don't want to redo it every other week. The types of tape I've tried aren't great on the rubber and tear and pull off pretty quickly, or have an awkward texture. The tiles are colored blackish so I likely wouldn't see any knife marks in it.
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Apr 30, 2024 15:08
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esquilax posted:I have a squat rack and separate standalone bench at home. It's all sitting on hard rubber floor tiles. When doing bench press or other rack exercises I prefer to have the bench positioned reasonably close to the exact middle and reasonably square. Eyeballing isn't enough for me to always get it close enough on the first try without an annoying amount of effort. If you can't tell, why does it matter?
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Apr 30, 2024 15:18
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esquilax posted:I have a squat rack and separate standalone bench at home. It's all sitting on hard rubber floor tiles. When doing bench press or other rack exercises I prefer to have the bench positioned reasonably close to the exact middle and reasonably square. Eyeballing isn't enough for me to always get it close enough on the first try without an annoying amount of effort. Paint? Cut a stencil and use a spray can maybe, or use a paint pen?
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Apr 30, 2024 15:28
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man
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Or cut plus pink nail polish?
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Apr 30, 2024 15:29
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Tiggum posted:If you can't tell, why does it matter? I can't really tell when I'm standing, but even a half inch is obvious when I'm lying down and positioning my hands on the bar knurling. So mostly a broken brain, but when unracking/reracking a heavy bench press it's easier to avoid racking issues, or using one arm more than the other, or distractions, compared to when the bench is straight and square. dokmo posted:Paint? Cut a stencil and use a spray can maybe, or use a paint pen? Is there a particular type of paint that works well underfoot and adheres well to rubber? esquilax fucked around with this message at 15:50 on Apr 30, 2024 |
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Apr 30, 2024 15:44
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esquilax posted:I have a squat rack and separate standalone bench at home. It's all sitting on hard rubber floor tiles. When doing bench press or other rack exercises I prefer to have the bench positioned reasonably close to the exact middle and reasonably square. Eyeballing isn't enough for me to always get it close enough on the first try without an annoying amount of effort. Center the bar and align the bench relative to it. With some practice you'll get used to the right positioning.
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Apr 30, 2024 15:56
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Make some sort of jig from a piece of wood
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Apr 30, 2024 15:58
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esquilax posted:I have a squat rack and separate standalone bench at home. It's all sitting on hard rubber floor tiles. When doing bench press or other rack exercises I prefer to have the bench positioned reasonably close to the exact middle and reasonably square. Eyeballing isn't enough for me to always get it close enough on the first try without an annoying amount of effort. I think nail polish adheres fairly well to rubber. I'd try putting a dot on the legs of your bench and a dot on the floor when it's in the right spot. Then line up the dots when it's time to bench press. My own method of solving this was to line up a feature of the bench with a crack in the flooring. Last place a bolt on a leg was about a finger width from the intersection of some floor pieces.
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Apr 30, 2024 17:10
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Is there a way to find out if I'm on anyone's ignore list? And, if I am, how many? I worry for the sake of these forums that I am.
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Apr 30, 2024 19:05
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credburn posted:Is there a way to find out if I'm on anyone's ignore list? And, if I am, how many? I don't think you can see how many people have you ignored unless you're in the top 100 here: https://forums.somethingawful.com/stats.php?statid=4#jump You're probably going to have to work a lot harder to make that list because currently you would need more than 300 people to ignore you
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Apr 30, 2024 19:46
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credburn posted:Is there a way to find out if I'm on anyone's ignore list? And, if I am, how many? You know that people will put you on ignore just for this post, right?
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Apr 30, 2024 19:49
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mystes posted:Apparently you can tell if an individual user who has platinum has you ignored because the "Message" button won't appear under their posts for you (it will never appear for users who don't have platinum), although honestly it probably shouldn't work that way I’m surprised how many active posters I recognize. Would have figured that the most ignored were from the bad old days of SA and long since banned
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Apr 30, 2024 19:52
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Similar question, how do you un-ignore someone here? I thought the Ignore button used to toggle, but I don't think that works anymore.
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Apr 30, 2024 19:57
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CzarChasm posted:Similar question, how do you un-ignore someone here? I thought the Ignore button used to toggle, but I don't think that works anymore.
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Apr 30, 2024 19:59
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Fruits of the sea posted:I’m surprised how many active posters I recognize. Would have figured that the most ignored were from the bad old days of SA and long since banned
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Apr 30, 2024 20:09
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That does explain a few entries.
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Apr 30, 2024 20:56
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who is the "someone that is banned" at the top who is ignored by like two thousand more people than the next person on the list? iirc there was someone who got banned for trying to add the entire forums to their ignore list and it caused a bunch of problems and i think it had something to do with that but not sure how it would result in being mutually ignored by so many people
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Apr 30, 2024 21:45
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I think it's a collection of people that can't be separated out anymore due to radium. Or there's this story about a username that would crash your browser or something like that. I do not know the facts, but that'd get you right up there right quick, I suppose.
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Apr 30, 2024 21:53
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I know a lot of insects have their niches and are useful (bees are the big ones that come to mind, because I don't know any others), but what loving good are mosquitoes?
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Apr 30, 2024 22:05
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Leave posted:I know a lot of insects have their niches and are useful (bees are the big ones that come to mind, because I don't know any others), but what loving good are mosquitoes? lots of things eat them. birds, fish, reptiles, spiders, other bugs, etc.
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Apr 30, 2024 22:11
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Leave posted:I know a lot of insects have their niches and are useful (bees are the big ones that come to mind, because I don't know any others), but what loving good are mosquitoes? They’re very good to themselves
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Apr 30, 2024 22:15
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Leave posted:I know a lot of insects have their niches and are useful (bees are the big ones that come to mind, because I don't know any others), but what loving good are mosquitoes? Lots of people seem to want to eradicate malaria and zika and other diseases by genociding the mosquito species that can carry those diseases. I'm sure we'd be doing it if it was feasible to do. The risk to the overall ecosystem seems low.
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Apr 30, 2024 22:21
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Leave posted:I know a lot of insects have their niches and are useful (bees are the big ones that come to mind, because I don't know any others), but what loving good are mosquitoes? They’re pollinators. Female mosquitoes are the only ones that drink blood, and even they also feed off of nectar and honeydew and such. The males feed off of those things exclusively. They’re also a prey species for fish and amphibians and all sorts of things that live in the water.
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Apr 30, 2024 22:37
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Leave posted:I know a lot of insects have their niches and are useful (bees are the big ones that come to mind, because I don't know any others), but what loving good are mosquitoes? They are also pollinators in many environments. And in general, ecosystems are delicate, incredibly entropic systems that don't handle human timescale changes particularly well, ala cane toads or africanized bees or gypsy moths or artificial tire reefs or defoliants or H. pylori etc. etc. etc. We are big dumb idiots and we don't realize the importance of thingd until ecosystems or species or humans or pets etc. die after we try to "fix" them.
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Apr 30, 2024 22:43
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Dr. Stab posted:Lots of people seem to want to eradicate malaria and zika and other diseases by genociding the mosquito species that can carry those diseases. I'm sure we'd be doing it if it was feasible to do. people i know in colombo sri lanka claim that mosquitos (or at least the type that carry dengue fever) have been eliminated locally, and when i was there ten years ago it did seem like i only got bit when i travelled outside the city. but thats probably a lot easier than a planet wide destruction of the species
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Apr 30, 2024 22:46
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On a related note, I remember an article making the rounds a few years back making the case that we could basically eliminate wasps with no major downsides to the overall ecosystem. I've always been skeptical of the claim, but is there anything to it? IIRC they said fig trees would suffer, but nothing else depends on the wasps or figs to a significant enough degree for their absence to cause much disruption.
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Apr 30, 2024 23:16
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Atahualpa posted:On a related note, I remember an article making the rounds a few years back making the case that we could basically eliminate wasps with no major downsides to the overall ecosystem. I've always been skeptical of the claim, but is there anything to it? IIRC they said fig trees would suffer, but nothing else depends on the wasps or figs to a significant enough degree for their absence to cause much disruption. Wasps as parasitoids are major regulators of plant-consuming insects, and eliminating them from any environment where they are native would likely lead to devastating trophic disruption analogous to the removal of large predators in many environments. If "they" were seriously making a claim as broad as you are purporting then "they" are absolute morons. TL;DR: Wasps eat bugs that eat plants. No wasps, bugs eat too much plants, now bugs starve and everyone dies.
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Apr 30, 2024 23:35
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Only some species of mosquito carry the various plagues too.
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Apr 30, 2024 23:40
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Given the HUGE numbers of insect species that are already being inadvertently wiped out by human activity, I suspect that intentionally adding just a few more extinctions onto the pile wouldn't significantly increase the ecological damage we're already doing. But then I'm not an entomologist or an ecologist or anything, so what do I know?
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Apr 30, 2024 23:45
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I heard the other day that it might be okay to eliminate the specific mosquitoes that bite us (and cause malaria) because they pretty much evolved alongside us and aren't supporting ecosystems with their presence. And that there are plenty of other species of mosquito that don't bite humans, which mosquito-eating animals can eat. Having trouble finding the source, though. I thought it might be the recent Sawbones ep on insects, only looking at the transcript it doesn't seem to be...
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Apr 30, 2024 23:48
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I mostly ask because, as it's warming up, they're beginning to appear again, and gently caress these little bastards
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Apr 30, 2024 23:53
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Powered Descent posted:Given the HUGE numbers of insect species that are already being inadvertently wiped out by human activity, I suspect that intentionally adding just a few more extinctions onto the pile wouldn't significantly increase the ecological damage we're already doing. "the damage would be hard to detect against the background noise of the massive damage we are already doing" is a rather extremely different situation than "it wouldn't cause any damage"
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May 1, 2024 00:05
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Hyperlynx posted:I heard the other day that it might be okay to eliminate the specific mosquitoes that bite us (and cause malaria) because they pretty much evolved alongside us and aren't supporting ecosystems with their presence. And that there are plenty of other species of mosquito that don't bite humans, which mosquito-eating animals can eat. I wouldn't trust us to stop there once we crossed that line.
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May 1, 2024 00:17
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