I'm gonna keep on dancin'...

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See, that’s what the app is perfect for.

Sounds perfect Wahhhh, I don’t wanna
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headspace-hotel

How to begin a sustainable way of life

This is a draft of something I've been writing for a couple months. It is mainly focused on the culture of the USA. Feel free to repost or otherwise share, with or without credit.

Do not tell people what to do—help them do it! 

Give the gift of relief from being forced to engage in society’s unsustainable ways of life. 

  • “People need to eat more plant-based foods.” ->Talk about your favorite recipes, give others recipes, cook for them, and grow vegetables and plants in your garden and give them away as gifts. 
  • “People need to repair their clothes.” -> Offer to repair others’ clothes, and teach people how to repair their clothes. 
  • “People need to buy less clothes.” -> Give them old clothes that you don’t want, help them repair their clothes
  • “People need to buy less plastic stuff.” -> Learn to make things that can serve the same purpose, such as baskets, and give them as gifts. Let people borrow things you own so they don’t have to buy their own. 
  • “People need to stop using leafblowers and other gas-guzzling machinery.” -> Offer to rake the leaves. You can use them as compost in your own garden. 
  • “People need to be more educated about nature.”-> Learn about nature yourself. Tell people about nature. Be open about your love of creatures such as snakes, spiders, and frogs. Do not show awareness that this could be strange. You are not obligated to quiet down your enthusiasm for creepy crawlies to demonstrate awareness that it is weird. Point out at every opportunity how these animals are beneficial. 
  • “People need to use cars less.” -> Offer rides to others whenever you must go somewhere. Whenever you are about to go to the store, ask your neighbor or your friend who lives along the way, “Is there anything you need from the store?” 

You cannot control others’ behaviors, but you can free them from being controlled. 

If you think to yourself, “But this would be so difficult to do!” ask yourself WHY? Why does your society coerce you into less sustainable ways of living, forcing you to consume excessively? After thinking about this, consider that it is less simple and easy than you thought to make more sustainable choices, so why would you judge others for not doing it? 

Do not act alone—act with others! 

Environmentally friendly behaviors that can be done alone, without collaborating with or consulting another person, are the least powerful of all. Whenever an “environmentally friendly” behavior is suggested, figure out “How can I give this as a gift?” or “How can I make this possible on the level of a whole community?” 

“Personal choices” do not work because every single person has to make them individually. If you are focused on making your own personal choice, you are not focused on others. If you are not focused on others, you are not helping them. If nobody is helping each other, most people won’t be able to make the “personal choice.”

You inherently share an ecosystem with your neighbors  

            Start with your neighbors, the people physically close to you. You live on the same patch of land, containing roots from the same plants and trees. You can speak to them face to face without traveling, which means you can easily bring them physical things without using resources to travel. 

            Always talk to your neighbors and be friendly with them. Offer them favors unprompted and tell them about how your garden is doing. Do not be afraid to be annoying—a slightly annoying neighbor who is helpful, kind, and can be relied upon for a variety of favors or in times of need is a necessary and inevitable part of a good community. If you make the effort to be present in somebody’s life, they will have to put up with you on some occasions, but that is just life. We cannot rely on each other if we do not put up with each other. 

Simply spending time with someone influences them for good 

Every hour you spend outside with your neighbor is an hour your neighbor doesn’t spend watching Fox News. Every hour you spend talking with someone and interacting with them in the real world, eating real food and enjoying your real surroundings, is an hour you don’t spend only hearing a curated picture of what reality is like from social media. 

            Isolation makes it easy for people to become indoctrinated into extremist beliefs. When someone spends more time alone, watching TV, Youtube, or scrolling social media, than they do with others, their concept of what other people are like and what the world is like comes more from social media than real life. TV and online media are meant to influence you in a specific way. Simply restricting the access these influences have to yourself and others is helpful. 

A garden is the source of many gifts 

If you grow a garden, you can give your neighbors and friends the gift of food, plants, and crafted objects. This is one of the foundational ways to form community. When you give food, you provide support to others. When you give plants, you are encouraging and teaching about gardening. It is even better when you give recipes cooked from things you grew, or items crafted from things you grew. You can also give the gift of knowledge of how to grow these plants, cook these recipes, or craft these objects. 

More on gift-giving

            Some people are uncomfortable with receiving items or services as gifts. They want to feel like they are giving something back, instead of having obligation to return the favor hanging over them. 

            It can help to ask a simple favor that can be easily fulfilled. People generally like the feeling of helping someone else. 

When you give someone a gift, it can help to say something like “Oh, I have too many of this thing to take care of/store/eat myself! Do you think you could take some?” This makes your neighbor feel like they are helping you

When allowing others to borrow items, you might not get them back. Don’t worry about that. It just means the item found a place where it was needed the most. You can ask about the item if you think it might have been forgotten, and this can create an opportunity for a second meeting. But don’t press. 

If the person you give to insists upon some form of payment, this is a good opportunity to negotiate a trade. 

Ask to be given compostable or recyclable things 

Ask your neighbor to save compostable scraps, biodegradable cardboard and paper products, and any other items that might be put to use. Use them in your own compost pile. Or, start a compost pile at the edge of the yard where you both can add to it. Remember that “wet” compost like vegetable and fruit bits needs to be mixed with twice as much of “dry” and “woody” compost like cardboard, leaves, small twigs, paper and wood bits. 

Use the front yard for gardening

Overcome the cultural norm that the front yard is only decorative. Use the front yard for gardening so you can be seen by others enjoying your garden, and others can witness the demonstration of the possibilities of land. In the front yard, anything you do intentionally with your land can be witnessed. It also makes you a visible presence in your community. 

Grow staple foods 

Don’t just grow vegetables that cannot be the core component of a meal themselves. Grow potatoes, dry beans, black eyed peas and other nourishing, calorie-dense foods. Grow the ingredients of meals. You could even build a garden around a recipe.

Invite neighbors and friends over to eat food made from things you grew 

Be sure to send them home with leftovers.  

Grow plants for baskets 

Containers are one of the fundamental human needs. If we had more containers, we wouldn’t need plastic so much. You can learn to make baskets, and to grow plants that provide the raw materials for baskets. 

If someone rakes their leaves, ask to have the leaves  

If you see someone putting leaves in bags, don’t be afraid to ask if you can have the leaves. More likely than not they will be happy to agree. 

Collaborate with neighbors to plant things in the no-man’s-land of the property line 

In the border land between your neighbor’s yard and your yard, it is almost always just mowed grass because no one can plant anything without it affecting their neighbor. But these border lands add up to a lot of space. It would be much better if you talked to your neighbor about what would be nice to plant there, and together created a plan for that space. 

Give others the freedom to wander 

Make it clear that you will not get mad if the neighbor’s kids play in your yard or run across it. Invite the neighbors onto your land as much as possible. Tell them they are allowed to spend time in a favored spot whenever they would like.  

The power of the hand-made sign 

If there is a yard sale, you always know about it because of the hand-drawn signs placed around. Therefore, a cookout or unwanted item exchange can be announced the same way. In rural areas I have seen hand-made signs that say: FIREWOOD or WE BUY GOATS or EGGS. This is one of the few technologies of community that remain in the USA. If someone who looks to buy and sell can put up a hand-made sign, why shouldn’t you?  

Religious people or people with strong political opinions like to put signs everywhere. If they have the confidence and courage to do so, why shouldn’t you? 

So if there is a message you would like everyone to see, use the simple power of the hand-made sign. Proclaim “BEE FRIENDLY ZONE!” above your pollinator garden with all the confidence of a religious fundamentalist billboard. Announce to the world, “VEGETABLES FREE TO ALL—JUST ASK!” “WE TAKE LEAVES—NO PESTICIDES.” Instead of YARD SALE, or perhaps in conjunction with YARD SALE, you can write, PLANT EXCHANGE or SEED SWAP or CLOTHING SWAP. Who can stop you? 

Someone has to do it for society to change  

Some of these ideas might be eccentric, strange, or even socially unacceptable, but there is no way to change what is normal except to move against it. Someone has to be weird. It might as well be you. 

Pinned Post I love this post forever and ever
e-the-village-cryptid
heatherwitch

My resolution last year was to do one thing before bed that would make my morning feel easier, and that’s become a daily habit that I’m carrying into this new year.

Some nights even filling up the kettle and setting an empty mug out for my morning tea felt hard. But I was always thankful for it in the morning.

Other nights, one thing would lead to another, and I’d wake up in a clean house with everything ready to go.

And, on a rare few nights, the one thing that I could do to make my morning easier was going straight to bed and allowing myself to rest.

What stayed the same each day is that I would take a moment to think of what I could do for my future self and do it, even after a hard day. And I would wake up knowing that I had done my best and any effort—no matter how small—was a kindness to myself.

one-bite-is-undercover

I’ve been doing a lot of “a treat for future me” moments lately.

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heatherwitch

That’s a great way to look at it, and I love this artist! (Anna-Laura: instagram / website)

hiveswap
hiveswap

GOLDFISH MAN HAS FUCKED UP AGAIN

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From the creator of "i waved a uv steriliser rod directly in front of my eyes and had to go to the ER" and "i put water on the basement carpet so now everything smells even more like cat piss" i present:

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Bare hands too it's some UNGODLY LUCK that it didnt sting him

hiveswap

Cant forget that time he would routinely handle bloodworms that he was feeding to fish without gloves (which can lead to development of pontentially serious allergies overtime) until the comments made him stop. how the fuck is he alive.

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The thing is that as far i know he genuinely knows his shit when it comes to goldfish. It's just that sometimes he'll make a video, with full confidence, about a situation that only someone with no survival instinct would get into

averagefungus

This man is like if Ordinary Sausage was a marine biologist

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He's not a marine biologist he's a goldfish breeder (which are freshwater fish also)

girldixieflatline

Anonymous asked:

I’m not very familiar with engineering so I’m curious as to just why a laminar flow rocket engine is such a terrible idea. You don’t have to explain, but if you wanted to give an explanation I’d be interested in hearing!

yokowan answered:

okay hi anon idk what your base of knowledge is with any fluid mechanics or rocketry stuff so I’m writing this for a very general audience with no experience. hopefully i won’t xkcd average familiarity myself.

Part 1
LAMINAR VS TURBULENT FLOW AND WHAT THE HELL IS A BOUNDARY LAYER

Laminar flow is a flow condition that describes how a fluid is moving in relation to a surface. It means all the fluid is moving more or less with the bulk flow, and there’s no rapid changes in velocity anywhere. The flow speed changes gradually from zero at whatever surface the fluid is moving over¹, to the free-stream velocity at some distance away from the surface.

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Through a pipe, it looks roughly like this. Parallel streamlines all moving in one direction all niceys. The area between the surface and the free-stream region is the boundary layer, and it’s the primary source of energy loss in fluid systems. Laminar flow occurs at relatively low flow velocities² along very smooth surfaces. If you try to push the fluid too fast, you start getting turbulence.

Turbulent flow is when a bunch of tiny vortices start forming along the molecular-scale imperfections on a surface. You get a region of flow where the fluid is swirling and disorganized, full of tiny eddies which change very dynamically from instant to instant.

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It’s usually sketched out looking something like this, but in actuality is it’s fairly fractal; you can observe vortices at basically every scale in a turbulent flow. From how disordered and messy the flow is, you might think that it’s less “efficient”. However, this isn’t actually the case! With about a heap of “it depends”, turbulent flow tends to have less energy loss than laminar flow!

As it turns out, those tiny little vortices are really efficient at transferring velocity between regions of the fluid. You still have to have a boundary layer between the surface and the free-stream velocity, but the velocity can change much more easily without fluid getting dragged by viscous forces. This means the boundary layers in a turbulent flow are typically much thinner, and this kind of flow is fairly desirable in a lot of engineering applications.

Laminar flow is definitely used in a few applications. For example, wind tunnels can’t have any turbulence over the test section because it’ll mess up your experiment. However, the main reason laminar flow has such a grasp on the engineeringtuber zeitgeist is because it looks pretty. And it does look pretty! You can make a hose that spits out a glassy, static-looking stream off water that’s perfectly clear and looks cool as hell in a youtube thumbnail.

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¹ Zero velocity on a surface is called a “no slip condition”, and it’s a pretty important thing in fluid mechanics. Every surface will have some amount of adhesion (stickiness) with the fluid, so it can’t have any velocity directly at the interface.

² Actually the quantity we’re concerned with here is called the Reynolds number, not velocity. The Reynolds number adjusts the flow speed for the viscosity of the fluid, its density, and the size of the object its interacting with. This lets us compare flows in very different substances, like water and air.

Part 2
HOW DOES A ROCKET ENGINE WORK ACTUALLY

A rocket engine is, fundamentally, a device for turning very angry chemicals into a high speed stream of gas.

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An injector injects a liquid fuel and oxidizer³ into the combustion chamber, which burn violently producing a bunch of hot, high pressure gas. The propellants have to be separate until they enter the engine (otherwise what you have is a bomb)⁴, so the purpose of the injector is to mix the propellants together while they’re inside the combustion chamber. There’s a number of different ways injector designs accomplish this, but most of them involve smashing together two streams going in opposite directions. This creates a very fine mist of propellant which burns very quickly. If a rocket engine has poor mixing, the propellants will burn quite slowly, and much of the combustion will occur outside of the engine. In the best case, this results in a loss of efficiency, in the worst case, it’ll result in the combustion instability and the rocket flaming out altogether.

As the high temperature, high pressure combustion products travel down the rocket engine, the combustion chamber starts to constrict. The constriction causes the flow speed to increase, like putting your finger on the nozzle of a garden hose. The flow speed keeps increasing until it reaches the speed of sound, and at that point it can’t be accelerated any faster. This condition is called choked flow,⁵ and it occurs in the narrowest part of the nozzle, called the throat.

In order to accelerate the exhaust stream to supersonic speeds, the flow is now expanded instead of constricted, in a part of the rocket engine called the nozzle. In supersonic flow regimes, the Bernoulli’s principle you’re familiar with (or maybe not) flips, and flow gets faster when its expanded.⁶ By the time it reaches the end of the nozzle, it’s going many times the speed of sound. The average velocity of the exhaust is what determines the efficiency of your rocket engine, so this is optimized to be as fast as possible.

³ Not every rocket engine uses a liquid fuel and a liquid oxidizer, but that’s not important to understanding here. Anything you can stick in a pressure vessel and burn can be a rocket fuel.

⁴ Monopropellants are a single liquid sitting in the tank, but they usually require some catalyst to burn so they don’t explode. And they still do sometimes.

You can think of the speed of sound in a gas as the speed at which “information” can travel through a gas, since pressure waves like sound are the only way one region of gas can be effected by neighboring regions. As the flow travels through the constriction, the gas has to be pushed along by the pressure from the gas behind it. When you reach the speed of sound, that pressure wave can’t move any faster than the gas, so the upstream gas can’t accelerate the downstream gas.

⁶ The math here is actually quite helpful! Without going into too much detail, the energy of a gas flow is proportional 1+ΓM², where Γ is a constant related to the molecular properties of the gas, and M is the speed of the fluid divided by the speed of sound, aka the Mach number. This term shows up in a lot of gas dynamics equations, and since it’s a quadratic term with two roots, basically every equation has two solutions: a supersonic one and a subsonic one. The two solutions tend to have flipped behavior, so a lot of stuff in supersonic flows is backwards from how it works in subsonic flows.

Part 3
THE PUNCHLINE

Remember when I said laminar flow requires smooth, symmetrical flow? As you might of noticed, at no point is that the flow condition in a rocket engine! In fact, every one of those components I discussed benefits from turbulent flow!

The injector is, perhaps, the most obvious. Chaotic, swirly flows are ideal for mixing propellants as fast as possible. You need that turbulent small scale motion to drive that mixing, otherwise you’re relying on diffusion⁷ which is very slow. This benefits the combustion chamber as well, as the turbulence more evenly distributes the temperature and prevents hot spots. Uneven combustion can greatly stress the structure of the engine, and cause really undesirable combustion instability.

As the flow travels through the choke and the nozzle, it’s moving very very fast. Laminar boundary layers in supersonic flows aren’t exactly feasible since you’re just moving so damn fast, but as I mentioned earlier, they’re not even more efficient. The huge boundary layers you get in laminar flow slow down the fluid a lot, which is really not something you want in a rocket engine. Any energy loss is a loss in efficiency, so thin, turbulent boundary layers are fairly desirable.

A “laminar flow rocket engine” is an idea that just sounds so absurd to anyone who has spent actual time doing aerospace engineering. And if you look at it, it’s not even really shaped like a rocket engine? There’s no expansion nozzle! The flow is limited to Mach 1 at the most, and there’s no way its even getting that fast if you’re going for laminar flow. And what the fuck is that injector???? There’s so much surface area! That’ll result in huge pressure losses and it’ll melt if you try to operate at any type of substantial temperature. It’s just. Bizarre all around.

⁷ If you’ve ever watched tea or dye or something slowly spread itself through a container of water without mixing it, that’s diffusion. It does not happen on rocket engine timescales.

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coyote picture unrelated

oh i dont know anything about rocket engineering but i studied biophisics ans physiology so it was kimda understandable to me! such a cool post i love random info!
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zmpl

this is a message to all babytrans. you may come across a subreddit or maybe even a 4chan board that is made up entirely of the most miserable trans people you’ve ever met. they have their own lingo borrowed straight from incel communities. but instead of being an incel where cishet men tell each other that women will never want to fuck them because of 2 mm of browbone, it’s trans women telling each other that they will never be a woman because of 2 mm of browbone. it’s trans men calling other trans men pooners for having a round face instead of a chiseled gigachad jawline. but they swear it’s not a toxic community because they’re all hiding under several layers of irony, so you can never really tell if someone is being serious. and it’s very important that you never visit these forums, even out of morbid curiosity

zmpl

since this post is making rounds i feel like resharing this for no reason in particular

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(comic by @tpwrtrmnky)

bedupolker
bedupolker

spy device in my pocket phone listening to conversations I have with medical professionals and immediately sharing that data with Instagram to barrage me with ads related to the thing I was talking about feels like it should be a violation of HIPPA and patient confidentiality but I dont know enough about the law to know for sure

bedupolker

also seems unlikely it was based off past internet searches/ad interactions... I work in clinical data entry right now, and search for a LOT of (mostly old people) meds to cross check things like generic names, use, side effects but im not getting ads promising me cures for hypertension and heart disease.

Kind of creepy, even aside from privacy issues, given the rise of pseudoscience in the US, hypothetically if someone did something serious going on like there's no real way to stop ads from preying in desperate people trying to convince them snake oil or horse dewormer is the way to go :/