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Sandwich


Acetone

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- Mon, 02 May 2016 12:59:32 EST uYoSzwJB No.77874
File: 1462208372041.jpg -(69778B / 68.14KB, 1024x576) Thumbnail displayed, click image for full size. Acetone
Are you going to be flagged if you try to buy pure acetone online? I imagine store-bought nail polish remover has some contaminants.
Experiences?
5 posts and 1 images omitted. Click View Thread to read.
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Betsy Hungerkatch - Thu, 17 Jun 2021 18:09:21 EST wOU7yFSB No.80039 Reply
>>77874


bro its caetone. produced shipped and sold in the tens of thousands of metric tonnes annually.

go on amazon or literally any website that sells it and order yourself a gallon jug. nobody will question you over a jug of acetone. speaking from personal experience.

you can order every reagent and solvent that isnt scheduled online and you will likely never hit law enforcement's radar unless you purchase in stupid large volumes

Overwhelming amount of physics

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- Wed, 21 Oct 2015 20:39:25 EST Fd+bN9n4 No.77312
File: 1445474365700.jpg -(39332B / 38.41KB, 500x417) Thumbnail displayed, click image for full size. Overwhelming amount of physics
Student here, I'm taking a calculus based physics course and it's ruining my life. Literally spend the whole day, roughly 6-8 hours working on physics problems daily because of the overwhelming amount of work that goes into our grade. To the point that I have been neglecting my other subjects and my grades in those classes are slowly going down, except physics.

My question is, is there any tips or advice on how to juggle such intensive courses and exceed in all of them at the same time? I need to reevaluate my plan because I feel like if I spend less time on physics, my grade will go down since the material is so dense.

Stories of people in higher academia are appreciated. Also tips to unwind and not let physics ruin your life.

For example, I worked on 8 hours of crunching problems in my problem set all day. Now that I'm home, I feel the need to continue but my brain feels like mush.

PS.

I take adderall on the weekday and I don't have ADHD, just because I want to pass this class.
18 posts and 6 images omitted. Click View Thread to read.
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Sophie Blatherridge - Sun, 11 Apr 2021 22:36:25 EST aYPqrzjN No.80025 Reply
>>80014
It was the top thread when I saw it so I answered the question. I didn't know 420chan has such old threads lying around. On 4chan you're thread is done after a day and archived>>80022

Thanks bro
>>
Oliver Tillingdale - Wed, 09 Jun 2021 11:48:37 EST IXpTASPs No.80038 Reply
I studied physics at college. Now I work on car manufacturing. I am fond ot technology and using automation tools. Control systems are an essential part of an automation system. The various types of closed-loop control techniques ensure the process variables to follow the set points. In our work we use https://eltra-trade.com/catalog/stock

Diversion Hydropower

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- Mon, 18 Jan 2021 20:56:05 EST cuBTyRdx No.79989
File: 1611021365942.gif -(48731B / 47.59KB, 604x454) Thumbnail displayed, click image for full size. Diversion Hydropower
Someone tell me why we don't just build canals and use diversion hydro for the majority of residential capacity needs?

Planning to build a DIY diversion hydro setup at a property in the North West U.S. soon to offset energy costs from owning an EV (small creek runs through the property).

Also fun fact... 96% of all battery storage in the U.S. comes from pumped storage. "Green" energy folks saying acid/lithium battery storage for solar/wind is somehow renewable blow my mind.
2 posts omitted. Click View Thread to read.
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Sidney Lightbury - Fri, 23 Apr 2021 17:56:35 EST sT/GRpvz No.80028 Reply
>>79989
It's definitely viable, but you have to have some serious flow and pressure to get a lot out of it. Real hydro projects involve gigantic dams and batteries of industrial-sized turbines. I'm really not sure how much you could expect to get out of using a backyard stream or positive-pressure stream, but if you can set something up at low cost then it's never a bad thing to have a little extra trickle of private electricity generation, just like if you were to chuck some solar panels on your roof to help some redundancy, or make hot water.

One of the things that gets expensive is adequate switchgear to be able to operate off of the grid entirely vs. just being able to reduce grid draw when the grid is up. Be sure to factor that in to your planning.

Another way to go if you're considering a stationary installation is nickle-iron batteries. These are old, heavy, and you have to do some work to source them in bulk, but they're frequently a great capacity per dollar if you can swing or split a bulk order, and they pretty much last forever and never take any damage from being deep cycled all the time. I'm not sure how it compares to setting up your own personal pumped storage system (which of course doubles as a way to have water pressure without a well and an electric pump) but it'd be something to look in to. As far as I know, nickel-iron batteries aren't in mass manufacture anymore, so you'd be looking at buying used and sucking up the transportation costs - they're very heavy.
>>
Rebecca Dobberham - Mon, 26 Apr 2021 19:16:29 EST Nnu4HuW+ No.80029 Reply
>Someone tell me why we don't just build canals and use diversion hydro for the majority of residential capacity needs?

I mean, we use hydroelectric for huge swathes of residential power needs. Some of that is through diversion and some of it isn't. In the United States, much of that is already tapped out. My region is filled with rivers and there's every conceivable form of hydroelectric station siphoning off as much as they can (your stream is likely not going to power much more than your lights, but you likely already knew that). From an ecological standpoint, hydroelectricity is not truly green. Huge concrete dams and sluices with constant water flow releases carbon dioxide through the breakdown of the calcium carbonate which makes up the bulk of the concrete we use to make these dams in the first place. Furthermore, damming up tributaries leads to a decline in downstream wetland ecology and alterations in upstream wetland ecology that reduce the capacity of these regions to serve as carbon sinks. Wetlands are very powerful carbon sinks as they naturally occur, so this damage adds up when you consider how much hydroelectricity is utilized.

Then, hydroelectric shares the same issue as nuclear power in the sense that startup costs are high (if you're planning on generating real power and not just hooking up some batteries to your yard) and have to be subsidized by the state, many locations aren't suitable for damming, many downstream locations in areas that could be suitable for damming are major residential or metropolitan areas which means damming such regions is a nonstarter (are you willing to pay the billions in eminent domain?), and the laws that govern energy transportation mean it's not a simple matter to simply transport energy from riverine regions to areas that lack major damable rivers (unless you ate the schizopill and think the Wardenclyffe Tower was the greatest tragedy to humankind).
>>
Thramby Cumberpatch - Thu, 06 May 2021 03:44:37 EST 7bi87AzV No.80035 Reply
>>80016
it would be better for fish than big dams
letting the rivers run free will save the planet

subject

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- Fri, 31 Mar 2017 00:52:19 EST 8Bqb2ojy No.78616
File: 1490935939445.jpg -(217743B / 212.64KB, 1674x670) Thumbnail displayed, click image for full size. subject
>hehe yeh bro meth is super simple to make just shake and bake my dude heh
5 posts and 1 images omitted. Click View Thread to read.
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Martin Pickfuck - Sat, 28 Mar 2020 06:08:07 EST 2jHBGjxs No.79818 Reply
>>79061
Uhm, yes this method works tried and true. Just got done doing it. Any acrylic enamel hardener. 110 octane racing fuel. Must filter to get lead out. P2p short method
>>
EasyE - Fri, 22 May 2020 02:02:47 EST 74Ra0Krc No.79889 Reply
>>79818
What happens after you put the 2 together for 12 hrs on hi and let cool for 12
>>
Rabbit - Tue, 04 May 2021 15:04:46 EST YdlXQb6+ No.80033 Reply
>>79818
Hey so i use the fuel and hardener. Wat about the clear coat. Can you break down the entire recipe

Gambiarra

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- Thu, 29 Apr 2021 22:20:10 EST gcJnRkBy No.80030
File: 1619749210101.gif -(21365B / 20.86KB, 100x151) Thumbnail displayed, click image for full size. Gambiarra
My Xmax Starry V2 has a problem: its lid became kinda loose, and because of it the circuit won't close and it won't turn on. I tried to get around the issue with aluminum foil, but it didn't work well enough for me to just forget about it. Is there anything I need to know before I just get a soldering iron and add a bit more metal to close the circuit? I don't know much about electronics, but I figured out which parts need to be touching for it to work, so I'd just put a little bit of solder there.

Incompetent Physics Professor

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- Thu, 18 Jan 2018 18:30:51 EST MsJwbibf No.78977
File: 1516318251029.jpg -(32669B / 31.90KB, 480x328) Thumbnail displayed, click image for full size. Incompetent Physics Professor
Sup /chem/,

I'm taking general physics 2 this semester and I have the same professor I had for physics 1. Now it's just algebra-based, and I've been through calculus, so I was able to breeze through Newtonian mechanics and all that. However this semester is about electromagnetism, circuits, and optics. All topics I have zero exposure to. Now the professor is new to teaching at the college level, his experience is teaching middle-schoolers. He is very (obliviously) condescending and talks to his class of adults like they are 12. He constantly makes sexist or racist jokes (but on the fence enough to not get in trouble) and is always ranting about his personal life or past experiences. When he finally does an actual problem on the board he always struggles with basic spelling and arithmetic, and often fundamentally misunderstands the physics concept he is trying to teach. Several times last semester I had to quietly approach him after class and explain how everything he lectured that day was flawed and the next lecture he would try to fix his fuckup but he ended up just giving everyone lots of freebies on the exams.

My concern is that in this new semester of material I will not get a good exposure or foundation in these topics and might be lost in future courses. Especially electricity and circuits, I really want to learn more about that. I am worried he will teach me some fundamental concepts backward or something. Other than pre-reading the text before class what would you guys recommend to get through this course when the professor is a complete idiot and in my opinion not qualified?
7 posts and 1 images omitted. Click View Thread to read.
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Martha Cavingson - Sun, 11 Apr 2021 17:07:35 EST aYPqrzjN No.80021 Reply
>>80013
Once again bro I'm a new poster coming from 4chan who didn't know the science threads on 420chan stay up for years

I come to ask something

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- Sun, 03 Jan 2021 15:12:09 EST EeD+1qUs No.79985
File: 1609704729972.jpg -(40418B / 39.47KB, 793x387) Thumbnail displayed, click image for full size. I come to ask something
I would like to ask, how can I start doxxear? I know I will sound like edgy child but I want to try to do this practice.
comment on your recommendations, tools, how can I get started, etc.
>>
Edwin Bannernick - Sun, 11 Apr 2021 13:08:09 EST yRn5sLX5 No.80017 Reply
>>79985
Dont bother. most "infosec" people dont conduct attacks, and info on how is tightly guarded behind paywalla that just reveal "use metaaploit" for a few grand. or youll get obnoxious dipshits that just say "Study the OSI model :)" as if it helps
>>
Edwin Bannernick - Sun, 11 Apr 2021 13:28:51 EST yRn5sLX5 No.80019 Reply
>>79996
case in point
>"how does i hack the box"
>"just use Open Sores Intel :)"
i.e. literally just "google it, retard". very helpful

Explosive potential of elemental potassium vs smokeless powder?

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- Fri, 08 Jan 2021 23:42:52 EST tcCvNWQn No.79986
File: 1610167372205.jpg -(6321B / 6.17KB, 225x225) Thumbnail displayed, click image for full size. Explosive potential of elemental potassium vs smokeless powder?
I watched a YouTube video of a guy that extracted the potassium from a shitload of bananas, resulting in a big chunk (30 grams maybe?) of potassium that he then threw into a lake. POW! SIZZZZZZZLE POW! This got me to wondering how potassium stacks up against modern smokeless powder. Also, shout out to YouTube channel Explosions&Fire, which is a dif YouTube channel but seriously awesome and you should go watch it.

So, can potassium replace gunpowder?
5 posts and 1 images omitted. Click View Thread to read.
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Eugene Clurringson - Mon, 08 Feb 2021 14:34:12 EST bJkRintO No.79995 Reply
>>79991
Recommending "Chemistry the Central Science" if you want a book
grab a pdf off of libgen.is
>>
Edwin Bannernick - Sun, 11 Apr 2021 13:19:08 EST yRn5sLX5 No.80018 Reply
>>79986
No. not only is it not nearly as energetic, but firearms work more on gas expansion than concussive force from ignition/detonation. gunpowder (black powder and modern nitrocellulose and other smokeless powders) work by producing a shitload of gas themselves and building big pressures that way rather than displacing air in exploding.

of course, modern rifles are mostly gas operated and most will fire once but not self-load if fed black powder, and especially so with anything that just explodes rather than producing gas.

furhermore, supersonic muzzle velocities are only possible because the gasses propelling the bullet down the bore have a higher speed of sound in that medium in air. this is why supersonic air rifles are uncommon and usually horribly inaccurate, and why people don't cram tannerite or fuckin C4 into a case rather than nitrocellulose. even exotic caseless ammo is more like firework stars or the stuff found in road flares than being a chunk of high explosive.

I want to access up to date streams of space satt3llites

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- Sat, 10 Apr 2021 19:50:19 EST Kwgvku7/ No.80011
File: 1618098619569.jpg -(616329B / 601.88KB, 768x1024) Thumbnail displayed, click image for full size. I want to access up to date streams of space satt3llites
Hey I live in the country and I see satellite feeds are available
But like an app where you can switch between the areas they're in. Tablets and phones are already like guides to the galaxy

I looked for something cool like this but was unable to find anything
>>
trypto - Sun, 11 Apr 2021 09:19:18 EST P8nk7/Yg No.80012 Reply
Look up the landsat program. That's a good place to start. I can't find the really useful website that lets you search the data easily. But here's an example of what kind of data it has: https://earthnow.usgs.gov/observer/

If you really get into it, you can actually get a Software Defined Radio for like $50 and download the data directly from the satellite. You can see some circlejerk nerds doing that here: https://www.circlejerk.com/r/amateursatellites/

slime universe theory

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!7BaphOmeTs - Sat, 10 Apr 2021 10:39:38 EST 1sLCpjxJ No.80010
File: 1618065578377.png -(232434B / 226.99KB, 1467x1410) Thumbnail displayed, click image for full size. slime universe theory
is it spam or is it super trippy and cool you decide

fr please somebody explain to me the flaws in this weird pile of conjectures cause obvs i actually cant do math super well

Graduate school advice

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- Thu, 11 Mar 2021 20:07:09 EST A6XAbPkj No.80005
File: 1615511229666.png -(450411B / 439.85KB, 652x466) Thumbnail displayed, click image for full size. Graduate school advice
Has anyone on /stem/ been to graduate school? How did you find programs/labs to apply to?

I'm interested in a pretty niche field, so it's hard to look up programs that would interest me. I hope to study fungal proteins/enzymes and their applications in biotechnology, which would be found in a microbiology department, but mycology is already such a tiny fraction of microbio that it feels impossible to find the labs I would want to join.

Is there any way to find prospective programs other than reading papers and looking up the authors?
>>
Emma Donkinlat - Fri, 12 Mar 2021 19:30:21 EST SP2+lcrx No.80006 Reply
>>80005

Shoot an email to authors of papers that interest you, see what universities have strong programs. Go visit your top choices and be aware you may have to move to where the good programs are.

Many graduate programs are interdisciplinary these days. My degree is in Chemistry but as a grad student I did everything from cell culture to synthesis to instrumentation. You should be open to picking up other skills and techniques outside your direct interest, it will come in handy in your career.

Think hard about what you want to do with your advanced degree.
academia? positions are limited and pay is minimal
Industry? more stressful but better pay and benefits
That may also influence the program you choose. Do they have successful alumni and connections that might help you.
>>
Doris Favingwell - Sat, 20 Mar 2021 09:46:09 EST Sy5xMAXi No.80007 Reply
>>80005
just graduated from a phd in physics.

i figured out where to apply based on having attended conferences, who my undergrad research advisor recommended, and papers. conference proceedings are very helpful (even if you don't attend them) because you see lists of abstracts associated with labs and schools. this gives you a more recent panorama of labs' research than their papers. Esp because so many conferences are online these days, there's a good chance you can attend a lot of them.

best luck

Hallucinogen compounds biochemistry

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- Tue, 02 Mar 2021 08:49:45 EST EiFK6JVz No.79998
File: 1614692985192.jpg -(103763B / 101.33KB, 1920x1098) Thumbnail displayed, click image for full size. Hallucinogen compounds biochemistry
Is there a major difference in effects between tryptamine- and phenetylamine-derivatives? (regardless of whether they are synthetic or natural)
Pic: proscaline, a synthetic phenetylamine-derivative
>>
Jenny Honkinman - Fri, 05 Mar 2021 19:31:26 EST A6XAbPkj No.80000 Reply
Phenethylamines are generally more stimulating. After all, amphetamine is only a methyl group away from phenethylamine. That's the only major difference IMO.

Every compound is a bit different but tryptamines and phenethylamines are both primarily 5HT2a agonists and not wildly different.
>>
Martin Fapperkack - Sun, 07 Mar 2021 17:30:32 EST P8nk7/Yg No.80002 Reply
>>80000
I think this is right. Both classes of psychs primarily act as partial 5ht agonists. But psychedelic phenethylamines sometimes also have similar effects to the stimulant phenethylamines. MDMA is the classic examples of this.

Shulgin writes about this kind of thing in phikal and tihkal, OP. Check them out if you haven't already.
>>
Shit Blungerhood - Mon, 08 Mar 2021 14:39:23 EST bJkRintO No.80004 Reply
1615232363535.jpg -(39559B / 38.63KB, 640x413) Thumbnail displayed, click image for full size.
>>80003
what the fuck are you doing my dude?

Boron tribromide demethylation of codeine

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- Mon, 10 Oct 2016 14:55:50 EST 9Opqdgsf No.78280
File: 1476125750712.png -(19996B / 19.53KB, 593x246) Thumbnail displayed, click image for full size. Boron tribromide demethylation of codeine
I am having trouble with this synthesis. I take 15ml DCM with 200mg codeine base dissolved and make sure its really dry with sieves. Then add something like 500mg of boron tribromide. Immediately the codeine drops out of the DCM solution... no doubt my homemade BBr3 contains a small amount of HBr and Br2. This stuff is unbelievably reactive with air, i've never seen anything fume like it in my life. So i waited/stirred 30mins then added ice/ammonia. No precipitate, i assume the codeine hbr simply dissolved in the aqueous. So next i tried the same thing but added 200mg DIPEA to soak up the acid. Still no morphine precipitate. I worked up both layers both times and verified there was no morphine, i thought it might be dissolved in the high PH aqueous layer but that's only possible with NaOH i believe, morphine should always be insoluble in ammonia hydroxide. I don't know what the problem is.

My boron tribromide is a bit red, i don't have enough to distill. I started from Br2 and Al to make aluminum bromide, anhydrous. Unfortunately i couldn't distill this either but i did leave it under vacuum to hopeful get the free bromine out. I melted it and poured it into another flask with potassium tetrafluoroborate and ended up with only a few ml of BBr3 distilling over. Next time i will use liquid tetrafluoroborate. All 3 of these things really fume like hell. I'm not looking forward to doing it again. I will try to use a vacuum next time, my joints weren't greased and it was pulling in more air then it was worth. I have to make sure i don't get the aluminum bromide on the ground joints as well, god damn what a mess. A propane torch wouldn't even get them apart i had to soak in WD40 then use a propane torch.
31 posts and 5 images omitted. Click View Thread to read.
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Esther Donderkare - Mon, 24 Oct 2016 19:43:12 EST 2Hc2eoG6 No.78327 Reply
Would it be easier to just buy some CYP2D6...
>>
Albert Henkinbanks - Wed, 26 Oct 2016 15:27:19 EST 9Opqdgsf No.78328 Reply
>>78327
I don't think it would be feasible to create an artificial liver, but i really don't know. I do know scientists have modified e.coli to produce thebaine. 2mg from 20grams of sugar isn't too good though, and i expect the modified bacteria would be incredibly fragile. So unfortunately we won't be growing morphine in mason jars like magic mushrooms anytime soon.

Countries like Canada are lucky just to have codeine. If you don't have an opiate to start from you are pretty much forced to grow poppies.

I've found my mercury, i'm going to shake the small amount of bbr3 i have left with it then try the reaction again.
>>
fromNepal - Tue, 02 Mar 2021 13:56:20 EST T37piBU8 No.79999 Reply
Has anyone succeded in demethylating codeine ?


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