I know people used integral to calculate volumes of objects or used geometry to solve quadratic equations. But how did they check the calculations? Did pythagoras used metres to check his theorem, did he have a ruler?

And other quantities like time, temperature, mass etc.

Hello,

I am currently working on an assignment and would greatly appreciate some assistance. I am trying to create a parametrized wooden ceiling in Rhino 7/Grasshopper. Specifically, I would like to adjust the number and width of the wooden beams supporting the floor, and also ensure the correct static height is calculated (please see Image 1 for reference).

ChatGPT provided me with a formula (Image 2), but I’m uncertain about its accuracy. The results I’m getting appear to be unusually small. For instance, when I input 16 beams with an 18 cm width (k=500), the formula suggests that the required beam height is only 9 mm, which seems incorrect.

Could anyone kindly provide guidance or insight on whether this formula is correct or if there might be a better approach?

Thank you in advance for your help!

Image 1

Image 2

Would this design be considered a tube-fitting bos/s seal or a gland seal? I've looked in the Parker Handbook but haven't come across this specific scenario. Any advice is appreciated.

Diagram: ImgurLink

My school has an old Tinius Olsen torsion tester used for small dogbone samples. All test pieces are cranked by hand, no power supply. Naturally there's also no data acquisition integrated into the system, which I am trying to remedy. I've been researching and understand that I need to take two sets of data concurrently: applied torque and rotational position/angular displacement. But I'm struggling to understand how to bring these data sets together in real time so I can get useful information like a stress strain curve. Any advice? Thank you!

As a reminder, /r/AskEngineers normal restrictions for career related posts are severely relaxed for this thread, so feel free to ask about intra-office politics, salaries, or just about anything else related to your job!

Hi, I don't know where to ask this...

I've been watching this pro CS2 player, and every time his crosshair is on an enemy, his face does this weird expression, like his prostate is being stimulated. And it got me thinking, could he be using some hidden vibrating thing like ass bead or plug to get enemy positions, maybe through morse code or something?

Does anyone know if devices like this exist? The ones that security can't detect, maybe because they're made of non metal materials?

Not asking for a friend, just trying to figure out if this is a thing in the esports world.

I'm working on converting an alternatir into an electric generator and I need to encase the rotor holding the magnets in resin so the magnets wont fly out as the rotor spins.

I'm looking for a pressure regulator that runs at 1 psi at all times regardless of flow. I imagine it would have to be something that adjusts dynamically. Does this hypothetical thing exist?

Thanks!

I've seen a lot of people claim that solar panel recycling will eventually lead to us no longer needing to mine for energy but that always seemed impossible to me. This is a question I have been thinking about for some time because a 100% recovery/recycling rate for anything is impossible. Even with established highly efficient recycling industries like for steel and aluminum some material is still lost to slag and dross (second question, are slag and dross economically recyclable or reusable and related to the main question how much steel and aluminum is lost in remelting/recycling process?), and that is a very simple case where you are recycling a single material/alloy. I've read about methods of recovering solar PV materials like in this article (Solar panels recycled with 99% efficiency without toxic chemicals). But to use many of these recovered materials like in this article you may still need to melt them down and/or chemically treat them so there is bound to be loss in both the electrical and structural component of the panels. So how much of the aluminum, silver, silicon, etc. can realistically be recycled and reused? I would imagine the reduction in mining would be the amount of material that can be recycled and only to replace the modules that are being recycled, because as energy demand goes up over time you will still need to mine more.

Now that I have a newer roof, I’m considering both solar electric and solar hot water.

While I see lots of advances in panel efficiency solar hot water is stagnant and from my understanding hot water or glycol panels can absorb up to 95% of available sunlight while electric panels struggle to reach 30.%.

What am I missing ?,

I understand how selective surfaces on solar thermal collectors typically operate: They aim to maximize absorptivity for the wavelengths of solar radiation, while minimizing emissivity at the infrared wavelength. Are there any selective surfaces that vary IR emissivity, reducing it only when the panel is exposed to sunlight? If not, is it technically conceivable?

The application will use the collectors for both daytime heating and nighttime cooling. So I’m looking for a way to minimize IR emissivity when the panels are exposed to sunlight, and then maximize it at night.

I need to build a wing spar for a wooden airplane, and in order to do so, I require proven allowables for the glued joints using epoxy adhesives. Preferably from a test-run or experimental data.

Any information much appreciated.

I thought that would be the easy part, but can’t find any wheels with set screws and that size bore.

I’m using this gear motor: https://makermotor.com/pn01007-38-3-8-d-shaft-electric-gear-motor-12v-low-speed-50-rpm-gearmotor-dc.

I’m also trying to figure out how much weight the wheel can support and how the size of the wheel affects the torque required to move that weight.

I recently got a job for a automotive shop that does custom wiring and I'm in charge of designing and creating these assemblies, currently we are using hand drawn drawings. I want to upgrade and make a digital one cleanly. I want to do this on my own and just present it one day to see if the company would like to invest in it. I also want to do just to build a portfolio. What software or what's the best way to create them? Doesn't need to be 3d any tips would be highly appreciated.

I've been reading about it for some years, but I'm still not very clear on it. So I need some clarification. So please tell me what I got wrong. Because I have no background in engineering.

Ford production:

Invented in the early 20th century. Focuses on getting as high volume as possible to offset machine cost. A tendency to use single machines for each part with one person per machine. the workforce tends to be low skilled with a high turnover rate. Lots of extra parts in warehouses or in the pipe

Toyota:

Invented later. the machines are less specialised. Workers can work on multiple machines. Lower total volume of production and a greater focus on making more reliable components that don't need later replacement. Inventory and throughput are lower. The workers are noted to be considered as less expendable and are part of the process of ensuring reliability.

What parts did I get wrong?

I have an acme lead screw that is used for a non captive stepper linear actuator. The end of the lead screw is pushing and pulling on another part. The end of the lead screw goes from the acme thread to a machined 4-40 threaded section, and then a smaller diameter shaft surface (bearing surface). I need to connect the lead screw to a plastic (PEI) part. Unfortunately, the threaded section is not long enough to leave enough thickness of material and use a nut. Any other ideas? Is there such this as a press fit collar for the shaft end and what material is recommended?

When I was an undergrad in mechanical engineering, I felt like there were basically two main sides of mechanical engineering:

1. the mechanisms, statics, dynamics, material mechanics, machine design side.

2. the thermodynamics, heat transfer, fluid mechanics, and HVAC side.

Of course there is overlap between all of these facets, but they fall into these two main categories in my mind. Is there a term for the first side? Like “solid mechanics” or something?

I am very interested in old-school/retro devices that don’t use any electronics. I type on a manual typewriter. I wear a wind-up mechanical watch. I love it. If it’s full of gears and levers of extreme precision, I’m interested. Particularly if I can see the inner workings, for example a skeletonized watch.

Are there any devices that I might have overlooked? What’s good if I’m interested in seeing examples of modem mechanical devices with no electrical parts?

Edit: I know a curta calculator fits my bill but they’re just too expensive. But I do own a mechanical calculator.

Intro

Some of the most common questions asked by people looking into a career in engineering are:

• What do engineers actually do at work?
• What's an average day like for an engineer?
• Are there any engineering jobs where I don't have to sit at a desk all day?

While these questions may appear simple, they're difficult to answer and require lengthy descriptions that should account for industry, specialization, and program phase. Much of the info available on the internet is too generic to be helpful and doesn't capture the sheer variety of engineering work that's out there.

To create a practical solution to this, AskEngineers opens this annual Work Experience thread where engineers describe their daily job activities and career in general. This series has been very successful in helping students to decide on the ideal major based on interests, as well as other engineers to better understand what their counterparts in other disciplines do.

How to participate

A template is provided for you which includes standard questions that are frequently asked by students. You don't have to answer every question, and how detailed your answers are is up to you. Feel free to come up with your own writing prompts and provide any info you think is helpful or interesting!

1. Copy the template in the gray codebox below.
2. Look in the comments for the engineering discipline that fits your job/industry. Reply to the top-level AutoModerator comment.
3. Turn ON Markdown Mode. Paste the template in your reply and type away! Some definitions:

• Industry: The specific industry you work in.
• Specialization: Your career focus or subject-matter expertise.
• Total Experience: Number of years of experience across your engineering career so far.

!!! NOTE: All replies must be to one of the top-level Automoderator comments.

• Failure to do this will result in your comment being removed. This is to keep everything organized and easy to search. You will be asked politely to repost your response.
• Questions and discussion are welcome, but make sure you're replying to someone else's contribution.

Response Template!!! NOTE: Turn on Markdown Mode for this to format correctly!

**Job Title:** Design Engineer

**Industry:** Medical devices

**Specialization:** (optional, but helpful)

**Total Experience:** 5 years

**Highest Degree:** BS MechE

**Country:** USA

---

> ### Q1. What inspired you to become an engineer?

(free form answer)

> ### Q2. Why did you choose your specific industry and specialization?

(free form answer)

> ### Q3. What's a normal day at work like for you? Can you describe your daily tasks & responsibilities?

(suggestion: include a discussion of program phase)

> ### Q4. What was your craziest or most interesting day on the job?

(free form answer)

> ### Q5. What was the most interesting project you worked on during your career?

(free form answer)

> ### Q6. What university did you attend for your engineering degree(s), and why should / shouldn't I go there?

(free form answer)

> ### Q7. If you could do it all over again, what would you do differently?

(free form answer)

> ### Q8. Do you have any advice for someone who's just getting started in engineering school/work?

(free form answer)

I need to add a separate power source (battery) to two Ford Transit 350 passenger vans. This new, separate battery should be isolated from the car's own electrical system (for the exception of alternator).

I'm thinking to connect the new battery to the working pair (two 61Ah, 12V Bosch batteries connected in parallel) in parallel and place two appropriately rated diodes (for + and - cables) between the two power sources to prevent the car's electric system from discharging the new battery and, at the same time, allow the battery to be charged by the car's standard alternator (it's a 150A alternator I think).

I want someone more qualified than I am to give me some recommendations on this. Mainly, what's the safe maximum battery size for a 150 amp alternator that already charges two 65Ah, 12v batteries? I would like to know how to calculate it for the future projects. And are two diodes really necessary to prevent any sort of electrical feedback or can I use just one (just for - cable, for example).

What do you guys do about people or companies like these? Do you blow them off? My product line we sell mainly orders of like 150 of our product, but I had one European based company buy 2. Just 2. Under ten grand. They are calling me every freakin week with questions. I just don't have time to deal with these guys. They did a test, it came back wrong, they sent it to us, we did the test, it's fine. They now want a copy of the manual which is still in development. Which would be exclusive to this company because they're the only ones who buy this configuration.

How do you politely tell a company they are asking for way too much?

Asking for the max allowed diameter of the hole.

Does the Monotype metal type typesetting machine provide kerning control in addition to selecting the matrix with calculated width? For example, in the word WAVE, the kernings between W, A and V are all negative. Can the machine do that?

Below are two sites that offer them for sale.

https://www.stratussupportsystems.com/product/QD-Quick-Detach-Pin-only

https://dirtybirdusa.com/products/fortis-quick-detach-sling-mount-m-lok-w-qd-swivel/

I've been doing a ton of CFD of various delta and swept and vortex generator and CFJ wings.

The Cl/Cd of a literal rounded plank at 10 alpha with CFJ at 1 million Re was over 40. This is insane, similar results with delta lift.

I theorize that it is almost completely newton's third law and flow deflection. The deflection on the bottom creates a high pressure, low velocity zone, and the top has the same free flow velocity, with lower pressure compared to the bottom.

The opposite is true in vortex lift, the vortex generates a low pressure zone.

A large amount of the energy consumed by planes is at takeoff, could we reduce the onboard battery size by using a cable system similar to what is used on aircraft carriers to launch the planes? Or would there be too much wear and tear / maintenance for this to be feasible? Could “shore” power be supplied instead? Basically a battery bank or generator to power the plane as it gets up to speed but not yet airborne.

is it possible to have a blower fan similar like this (where they are normally pulling air in from the top or bottom and pushing it out a side.) To instead make it PULL air from one side with the rest closed and blow it out the top while still keeping the slim line blower form factor?

I want to measure the hydraulic stiffness in underpressure, 0.3 bara. In the past, we've done this by using a syringe, filling everything with water, and correlating the pressure readings to the volume displacement of the syringe. This was done at atmospheric pressure so the syringe was decent enough. However, a standard syringe, that you can get in any pharmacy, leaks in 0.3 bara.

I was thinking of using a pneumatic piston (they're dirt cheap) and just replace the syringe in my setup with it. Obviously, all of them have max pressure spec but can't find any info on min pressure. So my question would be did someone ever try something like this? Do you think it would work?