Hi, I am working on heating a disk, I am using a dome with a light-bulb heater (radiation heating). I have observed uneven heating on the disk (mostly the edges are colder than the center). Are there any quick McGiver-ish solutions that could help me distribute the heat more evenly? preferably without contact to the disk (see diagram, disk in yellow)

https://preview.redd.it/ca119lv0luqc1.png?width=523&format=png&auto=webp&s=bc4a892ebbd4b9e9e0289372e70da5090884f50b

I just got mailed this invitation to attend this and I am unsure as to if it would be worth it. It’s only a week and costs over 4000 dollars to attend but it seems like it could provide some valuable experience. Has anyone here ever done this program before and if so was it worth it?

Apologies if I did not see a similar thread.

Firstly: condolences to all affected.

Why would the failure cascade like that? Should it not have "fuses" built in?

Is it bad design? Normal? Simply the span dictated this design?

Just a curious "engineer".

Intro

Welcome to the weekly career discussion thread, where you can talk about all career & professional topics. Topics may include:

• Professional career guidance & questions; e.g. job hunting advice, job offers comparisons, how to network

• Educational guidance & questions; e.g. what engineering discipline to major in, which university is good,

• Feedback on your résumé, CV, cover letter, etc.

• The job market, compensation, relocation, and other topics on the economics of engineering.

[Archive of past threads]

Guidelines

1. Before asking any questions, consult the AskEngineers wiki. There are detailed answers to common questions on:

• Job compensation
• Cost of Living adjustments
• Advice for how to decide on an engineering major
• How to choose which university to attend

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

2. 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.

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

Resources

• The AskEngineers wiki

• The AskEngineers Quarterly Salary Survey

• For students: "What's your average day like as an engineer?" We recommend that you spend an hour or so reading about what engineers actually do at work. This will help you make a more informed decision on which major to choose, or at least give you enough info to ask follow-up questions here.

• For those of you interested in a career in software development / Computer Science, go to r/cscareerquestions.

Or is it upto us to figure that out

Hi

I have a challenge regarding thermal expansion in the pipeline of sulfuric acid due to the trapped liquid. Due to the elevation differences, automatic valves are closed right after the storage tank and after the pump. The fluid in the pipeline expands due to expansion. One solution would be using expansion tanks, however, this equipment is generally used in HVAC or water systems. Is there any usage of such chemicals in expansion tanks that you know? Thanks.

https://ibb.co/XbMwcL6

I include the picture of the situation. the valves are kept close when the pump stops. if pump components leaks, the risk is the whole tank volume can drain. even having a leakage detector under the pump tray is not sufficient for line of defense. the exit valve after the pump is closed to create a pressure on the discharge section when the pump starts again for smooth operation, avoiding hammer.

How do solve an issue, wether it be a product, a process or a machine.

What do you do first? How does your thought process work?

I like to try and brainstorm first, and get as much info as possible to build some kind of story. Then explore and talk to other. Mostly a visual thought process for me.

Curious what goes on in the mind of other engineers, across the board.

I posted three years ago when the legislation was enacted that formalized the Professional Governance Act here in BC. At the time we wondered what that would mean for P.Eng. registrants that worked for unregistered firms.

Well, three years later, we're finding out. Received a letter from the association marked "CONFIDENTIAL" and referencing that there are a number of registered E.I.T.'s working for the same company as me as well (but not naming them). I won't post the letter, but the gist of it was:

• We see you're all working for an unregistered firm.
• Please have your firm start the registration process before the middle of April.

No consideration for the fact that i'm just an employee here, I have no power to force the company to do anything.

I sat on it a couple of weeks so my reply would be less inappropriate. In the end, I replied to tell them that yes, we got your letter, but you'll need to talk to the company if you want them to register, not the employees. They acknowledged my reply and say that they have reached out to our VP of Engineering... That's where the trail has stopped so far.

So now I get to wait and see if I get laid off because my P.Eng. is now a liability to the company, or whether the association pursues me further for not working for a registered firm, or whether the company decides they want to get with the program. Thanks, EGBC, for putting my job in jeopardy.

I've heard from one other company in the area that they have received a similar shakedown letter, they had a lawyer reply to it and haven't heard back yet. Anyone else fighting this?

The most common issues I deal with my team are from their lack of knowledge of documents I told them to read when they were hired. I even remind them often to read the documents when I review their work and see basic mistakes that are clearly addressed in the documents. Sometimes I point out the specific section, sometimes I go over it with them, and sometimes I just reference the document so they don't depend on me giving them the answer.

I know it's not a lack of understanding because they all openly admit that they haven't read the document(s) yet. One admitted that it's too boring and he's a licensed PE.

I am responsible for managing the technical competency of my team, but I'm not a supervisor so I can't can't use authority to motivate them. Their manager is useless so I have no help there.

Any suggestions?

I'm having trouble defining a QR code for serializing parts on my part drawing. I unfortunately don't have access to any drawing standards and the company I work for isn't concerned with them. I just need to show it in a way that supplier understands what needs to happen.

FWIW we're using this godforsaken program known as Creo. I wanted to simply sketch a square and next to it a rectangle, with number flags to the notes that define them as:

"White metal laser marking of GS1 Data Matrix with Human Readable Interpretation (HRI) on the right....[matrix size, separation, font, etc]"

While my coworker wants to screenshot the example code and paste it into the drawing. I'm hesitant to do that in fear that the supplier will burn that example verbatim.

Can anyone show or explain how they handle this sort of thing at their company? My understanding is that the GTIN and SN would be provided in the PO and that data is stored by our ERP/MRP system.

As often happens in life, I received a random memory of being a boy and reading an interesting magazine article. Sure enough, a simple Google search on the subject of the article I read, "artificial cloud Qatar 2022", will yield a myriad of results, mostly from circa 2011, about the development of a hovering structure intended to provide shade over stadiums in the harsh climate of the Middle Eastern country for the World Cup there in 2022. I am somewhat ashamed to say that, due to being terribly busy at the time, I did not follow the World Cup at all. To my knowledge however, this technology was never successfully developed and I have no information as to why. Would anyone happen to have more info on this? Was it cancelled simply due to the World Cup taking place in the 'cooler' months of November/December?

What is the most optimal ways to avoid the can being stuck???

Recently had a boss say that i couldnt possibly comprehend, a quite simple process i dont doubt, in a serious conversation. As though they are superior intelligence. When in reality i have more skills than they do and have improved almost everything they had before i came.

How do i deal with this? Do i prove myself to them

Or continue to annoy then by questioning them?

Context: i was suggest about simply investigating some spread sheets to help get better grasp of the issue first hand.

Who even says you couldnt possibly comprehend?

Intro

Welcome to the weekly career discussion thread, where you can talk about all career & professional topics. Topics may include:

• Professional career guidance & questions; e.g. job hunting advice, job offers comparisons, how to network

• Educational guidance & questions; e.g. what engineering discipline to major in, which university is good,

• Feedback on your résumé, CV, cover letter, etc.

• The job market, compensation, relocation, and other topics on the economics of engineering.

[Archive of past threads]

Guidelines

1. Before asking any questions, consult the AskEngineers wiki. There are detailed answers to common questions on:

• Job compensation
• Cost of Living adjustments
• Advice for how to decide on an engineering major
• How to choose which university to attend

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

2. 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.

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

Resources

• The AskEngineers wiki

• The AskEngineers Quarterly Salary Survey

• For students: "What's your average day like as an engineer?" We recommend that you spend an hour or so reading about what engineers actually do at work. This will help you make a more informed decision on which major to choose, or at least give you enough info to ask follow-up questions here.

• For those of you interested in a career in software development / Computer Science, go to r/cscareerquestions.

I was working yesterday on my project when I stumbled upon an issue I couldn't find any cost-effective solution for: is it even possible to generate gravity on the lunar surface just enough so that the water -assume with me that H2O in its liquid state- can flow smoothly in pipes? And what's the most cost-wise method of achieving that situation?

Ps: I couldn't find any such projects at Nasa Technical Reports Server

Hello,

I am trying to connect a 3phase AC turbine to my hybrid wind/solar MPPT controller. On the MPPT controller there are 3 slots for the wind turbine wiring with each slot labeled with a single letter U, V, W. The wind turbine I have does have 3 cables but none are labeled but colored Red, Blue, Yellow.

Unfortunately the turbine I got didn’t come with any paper work or specification sheet and I couldn’t find any from the seller about the wiring on the turbine.

Does it matter what wire goes into what slot on the MPPT controller? I have to imagine it does but I can’t find anything that tells me which go where.

I’ll provide any additional details if needed.

I think its closed mindedness and not having a big picture view. The small details and elements matter along with cost and value. But without an openmind to new ideas, and explorarion the process never starts.

Its easy to point out problems and reject ideas, without having tested them, whereas to have a discussion and add to a concept or suggest ways to test the theory in an open and mature manner is much more difficult and productive.

Theres some people who think being critical makes them seem smarter or have power. But really this makes them weaker.

Whats your experience with innovation, open/close mindness in disscussions with managers or co-workers

Do we want to see more realtime analysis and automation? How long before your factory will start to add more technology, sensors, IOT and robotics?

I am developing a small (about 1/3 the size of a bar of soap) electronic device that has a small (400mAH) lithium polymer battery in it. The device will charge from a USB micro connector at a fairly low charge rate of about 200mA.

I am having the housings injection molded and need to select my plastic. This is something that I have not done before.

One of the properties of the plastic I have to consider is the UL 94 flammability rating. I am presently considering the use of a material rated as UL 94 HB. Is this reasonable design choice for a product like this that has a small lithium ion polymer battery in it ?

Is there an official guide as to what the flammability rating of an electronic / electrical product should be based on type of item ?

Some of the higher rated UL 94 plastics have less desirable mechanical and visual properties, plus they are significantly more expensive.

If you have any examples please share. I noticed someone doing paper admin everyday, multiple times. This is in a store, in a factory. So just consumables etc. I thought maybe a digital system would help. Maybe. As they have to input it anyways.

Whats your thoughts?

So I recently passed my Civil PE in structural and I've been wanting to get into some side work. I was connected with an architect and he asked if I can do some calculations for residential work. He's expecting me to do some work on calculating beams, lintels and foundation but doesn't expect me to stamp. He's a licensed architect that's looking for technical advise in some of these elements.

I am interested in doing the work but don't have much experience working with real life situations. Should I get insurance and start a business to cover me?

Edit: thank you all for your advice. It only confirms my suspicions that he was trying to follow an idea when it can be disastrous when it goes wrong.

I can either, 1) form and a company, get insurance, and then perform work 2) work under another company that accepts this kind of work 3) not accept the risk and not work.

I'm inclined to take 3 for now and not stick my neck out until I have some more experience and then take the path of number 1.

Thank you all again for taking the time out to help

Been thinking about this for the past few days. So many questions come to mind given the looming threat of a potential collapse of the second tower.

How would they stabilize the building? Especially given debris absolutely everywhere. Presumably they couldn't resume search and rescue or get close enough to the building until it was deemed safe?

I'm assuming they'd try to bring the other one down eventually. Would they just call on hardcore patriots to go into the building to rig it for a controlled demo?

Is there a way to bring it down externally while avoiding collateral damage, considering the extreme density of lower manhattan?

How big would the perimeter need to be? Interested if Wall St. / NYSE like 300 yards away would have had to remain shut down for months.

Thought that this might be a good place to share an analytical model that has been created in MATLAB for modelling sinter and mesh wick heat pipes.

Would be great to speak to people who would be interested in using this and get feedback to improve it. I can also provide guidance on how to use it for anyone that it interested!

https://uk.mathworks.com/matlabcentral/fileexchange/160511-analytical-model-for-heat-pipes

Intro

Welcome to the weekly career discussion thread, where you can talk about all career & professional topics. Topics may include:

• Professional career guidance & questions; e.g. job hunting advice, job offers comparisons, how to network

• Educational guidance & questions; e.g. what engineering discipline to major in, which university is good,

• Feedback on your résumé, CV, cover letter, etc.

• The job market, compensation, relocation, and other topics on the economics of engineering.

[Archive of past threads]

Guidelines

1. Before asking any questions, consult the AskEngineers wiki. There are detailed answers to common questions on:

• Job compensation
• Cost of Living adjustments
• Advice for how to decide on an engineering major
• How to choose which university to attend

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

2. 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.

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

Resources

• The AskEngineers wiki

• The AskEngineers Quarterly Salary Survey

• For students: "What's your average day like as an engineer?" We recommend that you spend an hour or so reading about what engineers actually do at work. This will help you make a more informed decision on which major to choose, or at least give you enough info to ask follow-up questions here.

• For those of you interested in a career in software development / Computer Science, go to r/cscareerquestions.

Bit confused as to what an actuator actually is. My small research/understanding leads me to believe it’s more of a system than an individual mechanical component that does something. E.g, hydraulic actuators for car brakes would be the whole system of master cylinders and what not. Trying to work on an assignment and just not quite getting it

This was something I had been working on over a year ago to defeat small arms armor but never got to making prototype testing it in the real world. Things have changed recently and I am now considering going back to this project; however I am not 100% confident it will work like I think it does or simulations I did of it show.

​

EDIT: adding this to the top since it is an important find: https://www.researchgate.net/publication/317193440_Experimental_study_on_the_penetration_effect_of_ceramics_composite_projectile_on_ceramic_A3_steel_compound_targets

IDK how I missed this previously, must be Google search shenanigans, but this idea was tested with a 30mm for increased penetration. I haven't fully read the article since it's late, but the results indicate the penetration performance was improved.

​

TL;DR: What would you expect to happen when a 2 core bullet consisting of a very high hardness ceramic tip (core 1) and metal slug (core 2) impacts an armor plate made of high hardness ceramic tile followed by a UHMWPE liner? Can it fully penetrate? Why might it fail to penetrate?

​

WARNING: Long technical post with extensive FEA usage!

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​

General Idea Behind the Concept:

• Ceramic body armor is difficult to defeat because the ceramic tile fractures the metallic core and causes a large loss of velocity either completely shattering the projectile at the cost of the ceramic material at the location or the projectile resists complete shatter but does not retain enough energy to penetrate thru the woven high strength fabric liner (usually UHMWPE) behind the ceramic.
• Using a very high hardness ceramic core tip, upon impact the ceramic tip will shatter along with the ceramic armor tile. The energy transfer from this impact should be mostly transmitted into the shattering between the 2 ceramics and the slug behind the tip should retain most of it's energy to penetrate thru the liner behind it (to penetrate these liners, retaining high velocity is critical)

​

Validation Material Properties:

To validate the idea, I had obtained a licensed copy of ANSYS and used Explicit Dynamics to simulate the impacts. The material properties for the ceramics are the most influencing and difficult to model materials in the simulation. To ensure the properties used are correct, I used various scholarly articles that have done impact testing with FEA, typically with ANSYS or similar software, and created material models for each set of data. I would then run these tests in basic simple testing setups, like a steel ball hitting the ceramic at low speed vs high speed to verify the material behaved as we would expect it would under these situations. The validation helped refine the models a bit and removed any model behaving completely incorrectly. There were about 2-3 valid models for each of the 3 materials used in body armor and they yielded very similar results.

​

ANSYS Explicit Dynamics Testing:

These were very heavy simulations, around ~1-3 days for each. Before finalizing the material properties I would use, I would run lower element count simulations just to verify the properties and setup are working before running the major simulation.

Here is a link to the results which I will explain below:

https://imgur.com/a/uUESkTI (NOTE: destroyed elements are NOT VISIBLE in the video but existed during the simulation, nobody I talked to could figure out how to get it to show the original and as it erodes)

​

The bullet tip made of Silicon Carbide was selected and tested against armor made of .25" thick tiles and ~0.5" thick UHMWPE. This constitutes a Level III armor plate. I did Level IV plate testing but did not save the results as that was towards when I stopped working on this project. As you can see, Alumina freely shatters and the tip of the bullet even survives with minor damage. Silicon Carbide offers a much stronger resistance and most of the bullet erodes and only a portion of the slug remains intact with fair velocity post penetration. Boron Carbide almost completely erodes the projectile with only a small portion remaining at a slow velocity.

​

Possible Flaws in Testing:

• Alumina seemed extremely weak, albeit it is the cheapest and least durable material. I had went thru 6 Alumina models and they all yielded poor results.
• Ceramics, as I have been told, will create a fine powder that resists penetration when shattered. I have been unable to verify this claim when looking at real world penetration testing results or with FEA testing.
• No fractures occurred in any of the material models, which is quite odd. I investigated this quite heavily but could not find a reason why. The material property data seemed correct and the models showed fairly accurate results.

​

External Testing/Past Research:

I tried searching for similar ideas/tests done in the past but there were none. The only thing close to it was a full ceramic projectile, which had very poor results (as expected).

---------------------------------------------------------------

​

What I would like is outside perspectives on my testing process, the simulation quality, and the general concept of penetration via this method. Any thoughts, criticism, etc on this is greatly appreciated. At this time, I currently considering renewing my copy of ANSYS to perform more testing, but only if I am not chasing a dead idea. Let me know what you think, thanks!