#askengineer

[adafruit]

Desk of Ladyada - Tariff Talk! ASK AWAY! 📦🌎💸

We're doing the show tonight or Tues, so much is going on. Lots more questions came in too! Post yours before we go live…

This week was not a big week for engineering because we're neck-deep in tariff management! We had a video on Wednesday about the first round of tariffs announced—they have since been ratcheted up to 20% + 125% = 145% minimum on products from China and Hong Kong. "Retaliatory" tariffs on products from other countries have been paused, but there's still a 10% global tariff.

Then on Friday, it looks like some HTS codes

were "exempted" temporarily

Let's take a look at the CBP (link) and the exempt tariff codes

and see how they might apply to the kinds of stuff we use to do our electronics engineering.

The Great Search - How to Source Tariffed & Non-Tariffed Items on DigiKey

https://www.digikey.com/short/2nb7nzb3

Since this is the topic of the day, we'll be looking at how to purchase an item from DigiKey with tariffs in mind. DigiKey is a free trade zone, which means that if you're not in the USA, you will not have to pay additional tariffs on goods that are re-exported. However, for USA destinations, the new tariffs can add a significant cost if the component has its last manufacturing step in China.

Let's use the example of a simple I2C-controlled temperature sensor to see how our sourcing decisions may be impacted by tariffs.

[doomdoomofdoom]

Once, I wanted to know if it was reasonably possible to modify a (baseball) bat to add a taser function. According to r/askengineers, it is possible, but they were kinda bummed I wasn't talking about the animal.

there should be a hotline for me to call autistic people with specific hyperfixations every time i have a question

[did-i-fucking-stutter]

Now THIS is the shit I signed up for 😌👌

[santosantosanto]

Related 😢😢😢 

[ghostflowerdreams]

When The Electricity Goes Out In The Apocalypse

When an zombie apocalypse (or alien invasion, natural disaster, deadly contagion, etc.) happens the power grid will eventually go out. The reason for that is that the people who work in such places would want to go home to their families too. It would be their first priority so they wouldn’t show up to work when an apocalypse is happening and if they were already there they would want to leave. But that would be a huge problem if they were to suddenly stop working or to not show up at all.

Of course, there’s always the possibility that the employees may be force to continue working by the security, government, military, or whatnot to provide electricity for as long as possible. Or they’ll shut them down before they’re evacuated from the power plant. But again, that doesn’t seem likely because it is dangerous to leave a nuclear power plant unattended.

The power station, also referred to as a power plant (or generating plant), is an industrial facility for the generation of electric power. Most power stations in the world burn fossil fuels such as coal, oil, and natural gas to generate electricity. Others use nuclear power, but there is an increasing use of cleaner renewable sources such as solar, wind, wave and hydroelectric.

The problem is the nuclear power plants have a huge possibility in having a meltdown a few days after power loss. Of course, there are fail-safe mechanisms (SCRAM) put in place that triggers the nuclear plants to safety shut down in the absence of human maintenance. But they don’t always work because there could be other factors that could get in the way of it. A good example of this was the recent disaster in Fukushima Japan when a earthquake and tsunami caused compound equipment failures that resulted in coolant loss and subsequent reactor meltdown. 

Also, the fail-safe system is run with emergency battery (which last long enough for the diesels to kick in) and backup diesel generators (there’s several weeks worth of fuel onsite -- enough to last for 7 days or 30 days). It’s purpose is to keep the reactor cool after shutdown. However, that won’t last because nuclear plants (with very few exceptions) were only designed to survive local failures, not a full system by several weeks or years. So it would only be a matter of time, which some say it'd be a week or at best a month (it depends if there are any other complications) before the power plant begins to go critical. 

When it does it won’t be like Chernobyl. That had explosions, in which the raging fire spread to consume large swaths of land and it released radioactive plumes that swept over Europe and ravaged a whole city unusable. Any living thing near ground zero during or soon after the meltdown got a lethal dose of radiation within minutes. Even til this day, which is three decades after the explosion it still leaks radiation and it will continue to do so in many more years. But despite the high radiation levels the wildlife is thriving in the area because the absence of humans. It is still not clear how badly the local wildlife has been affected by the radiation. However, what we do know is that the animals, plants, and mushrooms still contain so much radioactivity that they are unsafe for human consumption.

Instead the meltdown would probably be more similar to Three Mile Island accident, in which the cooling malfunction and human errors at the plant caused it to have a partial meltdown, that released dangerous radioactive gasses into the atmosphere. About two million people were exposed to small amounts of radiation as a result of it. The public was assured that there wouldn’t be any significant health impacts from the accident. However, some of the locals believe that the state of Pennsylvania hid the truth, such as the deletion of cancers (from the public record, abolition of the state’s tumor registry, misrepresentation of the impacts it could not hide and including an apparent tripling of the infant death rate in nearby Harrisburg) and much more.

Unfortunately, people might not know that they’re sick until it’s too late. The symptoms don’t happen quickly, unless they were expose to a lot or were too close  to the source (in which case their radiation sickness would occur faster and be much more intense). After all, radiation is invisible; you cannot taste it, or smell it, or feel it on your fingers. So depending on the survivors location their exposure levels could differ. 

Someone at the edge of the fallout may not have noticed anything was wrong with them until years later (in the discover of cancer or something else). Others may feel flu-like symptoms (expect nausea and vomiting, headaches, fatigue, and fever). A little bit of radiation can be treatable (but sadly, it might not be easily available or accessible in the apocalypse). 

If they were closer to the radiation zone or within it, their symptoms would be worst. They would suffer a sunburn which would look like red patches, peeling skin, and sometimes blistering -- which would show up within 24 hours (and hair starts falling out too). But at lethal levels the route to death would be miserably painful. They would suffer severe vomiting, diarrhea, dizziness, and fever. Possibly unconsciousness and seizures too. Death would inevitable be within 48 hours. 

If it all goes well, the loss of power would switch the system to backup  generators which allows SCRAM to begin the progress of shutdown to the nuclear power plant  This is done by lowering control rods and cooling the system with water. The system continues to do that until there’s no more water or fuel, but that should be enough time for it to cool down to safer levels so that it won't meltdown. 

If it doesn’t work, it should give people plenty of time to evacuate the area. The containment domes around the reactor cores would contain most of the radioactive release (unless something were to happen to them or something else went wrong). But I doubt anyone would want to go in to check just to be sure that it all went well. So to be on the safe side, it would probably be best that the survivors keep their distance from all nuclear power plants (10 miles or more). It would be good idea for them to prepare in advance and mark the location of each of the nuclear power plants on a map. And to also measure out the 10-mile to 50-mile zones around them, so that they can figure out safe routes to travel.

I’ve notice that in many zombie apocalypse stories (and those that have an zombie apocalypse plan) they tend to forget the danger of power plants, especially those that are nuclear. They don’t just shut off quickly with a flip of a switch. According to the Nuclear Regulatory Commission (NRC), anyone living in a 10-mile radius of the plant would need to evacuate immediately because they would be hit with radiation plume. Outside the 10-mile zone, the NRC identifies a second zone that stretches out to 50 miles. Within this 50-mile zone, people won’t necessarily be directly affected, but food and water may become contaminated.

It’s important to know if you’re within the danger zone of a nuclear power plant and if so, where to go if you are. It’s also good to know what to wear to shield yourself from the radiation or what to take if you do get sick. This applies for your characters too because they would need to keep this in mind in the apocalypse. It would be another danger for them to deal with and it could also result in irradiated zombies. 

Did you know that there are 61 commercially operating nuclear power plants with 99 nuclear reactors in 30 U.S. states? Of these nuclear plants, 36 have two or more reactors. They’re located mostly in the east coast, which majority are at risk for core damage (that can lead to water loss which can lead to a meltdown) from earthquakes. These nuclear plants were not designed for the serious stresses of a large quake.

Currently, there are 450 nuclear reactors in operation in some 30 countries around the world. And 60 plants in 16 countries that are under construction. The United States has by far the most, followed by France, Japan, China and Russia.

NEI (Nuclear Energy Institute) - Map of U.S. Nuclear Plants

Wikipedia - Nuclear power by country

European Nuclear Society - Nuclear power plants, world-wide

Union of Concerned Scientist - Nuclear Power(less) Plants

Emergency Plan Guide - Are you within 10 miles of a nuclear power plant?

NRC: How Can I Prepare for a Radiological Emergency?

Smithsonian - Do You Live Within 50 Miles of a Nuclear Power Plant?

U.S. Energy Information Administration (EIA) - How many nuclear power plants are in the United States, and where are they located?

NBC NEWS - The 10 states that run on nuclear power

Business Insider - The 20 Countries With The Most Nuclear Reactors 

Scientific American - What Happens During a Nuclear Meltdown?

Scientific American - How Long Can a Nuclear Reactor Last?

PhysOrg - How does a nuclear meltdown work? (w/ Video)

Quora - What would happen if a nuclear reactor was suddenly abandoned (in a post-apocalyptic scenario)?

Quora - Do nuclear power plants have an automatic shutdown procedure if they are unmanned for a certain amount of time?

Reddit: AskEngineers - What would happen to nuclear reactors if the power grid failed forever.

Business Insider - How To Save Yourself From Radiation Poisoning After A Nuclear Disaster

Mayo Clinic - Radiation Sickness

CNN - Radiation: When to worry

CBS News - Radiation sickness: 8 terrifying symptoms (Photos)

Motherboard - 30 Years After Chernobyl, Here’s What Radioactivity Is Doing To Wildlife

HISTORY - Nuclear accident at Three Mile Island

The Washington Post - Three Mile Island’s residents remain on alert three decades after nuclear crisis

York Daily Record - Plagued by disease, ridiculed for their explanation: A TMI 'survivors' group is growing

HuffPost - People Died at Three Mile Island

Centre for Research on Globalization - NUCLEAR POWER PLANTS: The Very Real Possibility of A Global Nuclear Catastrophe

CBS News - What's the most at-risk U.S. nuclear power plant?

[sewambitious]

@ your pvc loom: I can’t force you to brave Reddit, but r/askengineers is full of over-helpful people who might be able to help tell you where to reinforce it so it doesn’t collapse. I’d help myself but my background is chemical engineering (not mechanical, which is who you’d want to answer). Anyhow I’d consider asking around engineering circles because I’m fairly sure it wouldn’t take very much math/work to fix that that but you would want someone that knows roughly what equations to solve and where to stabilize it. Good luck regardless! ✌️

Thanks for the advise! I actually know a lot of engineers so maybe I'll bug them about it lol. I was just trying to figure out on my own. I was working off of two pictures someone else made of the loom stand and thought I had it.

[hackernewsrobot]

How safe is Colin Furze's tunnel?

https://www.reddit.com/r/AskEngineers/comments/oh0vt0/how_safe_is_the_colin_furzes_tunnel/ Comments

[ace-pervert]

Forever preferably

[internaldynamicofthesexyfish]

Random refs

https://www.researchgate.net/publication/260038739_Theoretical_Perspectives_of_How_Digital_Natives_Learn

https://www.soundonsound.com/techniques/what-data-compression-does-your-music

https://www.reddit.com/r/AskEngineers/comments/2dwj84/why_does_hold_music_always_sound_so_terrible/

https://www.arte.tv/en/videos/RC-015228/homo-digitalis/

“rural africans” http://www.posgrado.unam.mx/musica/div/pdf/SoundStudies/Schafer.pdf

“higher sounds” https://www.nature.com/articles/s41467-019-10768-y

https://technological-simplicity.com/post-tech-or-post-technology-post-digital-technology-1cda37caff13

[smoothshift]

X-post from r/AskEngineers that I made: Does forced induction in a ICE increase the RPM of the engine or add more power at the same RPM compared to a NA engine? Or, am I misunderstanding how forced induction increases power altogether? via /r/cars

X-post from r/AskEngineers that I made: Does forced induction in a ICE increase the RPM of the engine or add more power at the same RPM compared to a NA engine? Or, am I misunderstanding how forced induction increases power altogether? http://bit.ly/2FIu9jI

[adafruit]

The Great Search - How to Source Tariffed & Non-Tariffed Items on DigiKey 📦🌎💸 https://youtu.be/I-eD6FSM0bU

[maximuswolf]

r/engineering's Weekly Career Discussion Thread [03 August 2020] via /r/engineering

r/engineering's Weekly Career Discussion Thread [03 August 2020]

Welcome to the weekly career discussion thread! Today's thread is for all your career questions, industry discussion, and a chance to get feedback on your résumé & etc. from other engineers. Topics of discussion include:

Career advice and guidance, including questions about which engineering major to choose

The job market, salary, benefits, and negotiating tactics

Office politics, management strategies, and other employee topics

Sharing stories & photos about current projects you're working on

[Archive of past threads]

Guidelines:

Most subreddit rules (with the obvious exceptions of R1 and R3) still apply and will be enforced, especially R7 and R9.

Job POSTINGS must go into the latest Quarterly Hiring Thread. Any that are posted here will be removed, and you'll be kindly redirected to the hiring thread.

If you need to interview an engineer for your school assignment, use the list of engineers in the sidebar. Do not request interviews in this thread!

Resources:

Before asking questions about pay, cost-of-living, and salary negotiation: Consult the AskEngineers wiki page which has resources to help you figure out the basics, so you can ask more detailed questions here.

For students: "What's your day-to-day like as an engineer?" This will help you understand the daily job activities for various types of engineering in different industries, so you can make a more informed decision on which major to choose; or at least give you a better starting point for followup questions.

For those of you interested in Computer Science, go to /r/cscareerquestions

Submitted August 03, 2020 at 05:15AM by AutoModerator via reddit https://ift.tt/316yE0A

[eurekakinginc]

Posted by liberollo via /r/artificial. Join Discussion: https://ift.tt/2LMeBQ2. Curated by: www.eurekaking.com

[explore-engineering-blog]

Cantilever Principle:

I saw a photo on here a while back demonstrating the “Cantilever Principle” which was used to build the Forth Bridge so as always I decided to do a quick investigation into it.

A cantilever, in its most basic form, is a rod that extends into free space and is anchored at one side. Placing a load on the end causes the cantilever to bend, the load is supported by tension and redistributed through the rod by compression into the wall, this removes the need for supporting columns or braces. Cantilevers can be both horizontal and vertical, for example a radio tower uses the same principle as a cantilever bridge, anchored to the ground instead of a pillar or riverbank, it also has applications as a chemical sensor.

Alongside this quick exploration I made a few diagrams to aid my understanding I hope they help you too :D

Sources:

http://www.innovateus.net/science/what-cantilever-beam

https://www.reddit.com/r/engineering

https://www.reddit.com/r/AskEngineers/

https://howbridgeswork.weebly.com/cantilever-bridge.html

http://design-technology.org/cantileverbridges.htm

https://sites.ifi.unicamp.br/oteschke/files/2014/03/Aula7-SNOMcantilevar.pdf

[booksbroadwaybbc]

Need help making a decision. 25 living at home. via /r/selfimprovement

Need help making a decision. 25 living at home.

I've been at home in this area for about ten years now, I went to community college and have degrees in civil engineering and land surveying. I live in the middle of nowhere with my parents and older sister and her son. Dad has pancreatic cancer but doing well.

I currently don't have a job, been out of one for three weeks now (it was seasonal and unrelated to degrees). Very few job opportunities around me and the closest hick town is 20 minutes away. I'm not interested in land surveying at all, the field work sucks and that is all that is available in my area, and absolutely no civil engineering job opportunities here either. Either way civil engineering also sucks (AskEngineers/comments/7owl1a/im_a_mechanical_engineer_but_have_a_little_bit_of/dscy9xu).

Just about the only thing that gives me purpose nowadays is my interest in the Italian language. I've been taking online classes from a native friend and I feel so accomplished after we finish a lesson, more than I have ever usually felt. I would love to go to school for something language related, preferably interpreting, if I knew there would be job security and availability after graduation. It seems to me like interpreters struggle with getting stable jobs, but that's simply from online forums.

Either way I'm worried about jumping in because I don't have many savings. The seasonal job I had is the closest job to me right now, and I had some unpaid bills to take care of, which thankfully I did, but the secondary goal was to have enough money to leave home. I don't have enough for that though. The job is over, I told them I can work but they don't put me on the schedule. I'm at home stressing about so many things, my dad, my future, our financial situation, and I'm having a hard time buckling down and keeping my mind focused on one thing. I'm afraid that I'll lose interest in whatever I go to school for and I'm afraid that my complete lack of money will prevent me from going anywhere, really.

I don't know what to do. Any advice would be appreciated.

Submitted September 20, 2018 at 10:28PM by sithrowaway5813 via reddit https://ift.tt/2QGziMx

[saltpeanutslive]

R/askengineering mod playing hard to get 😍😍😍

Original source. (Via r/iamverysmart.)