Why do some engineers place important data points in such a way as to obfuscate them behind other elements of the plan? Particularly when the data points in question are literally key components of the subject of that sheet?

I understand the tempo for churning out these plans is probably pretty great but it's perennially obnoxious as a new civil engineering construction estimator learning to do take-offs to see this dozens of times on a plan sheet and have to constantly cross reference other data points to get what I need to bid the project.

Examples of what I am referring to:

https://ibb.co/YFDQ9QSt

So if I had a unique piece of glassware but didn't necessarily want to test it until failure, could I establish a lower bound for its thermal shock resistance of that particular glass piece? And if there's only one of its kind, is a single trial sufficient or would I run multiple trials (except now thermal cycling is in play)?

Hey there,

I'm working on a project to automate putting 12mm wooden beads with a 4mm hole onto C-Lon thread. The main problem I keep running into over and over again is in order to hold up the thread and needle, it needs some sort of bracket or anchor, but that same device would prevent the bead from traveling down the length of thread.

Is there some way to accomplish this task? I'm thinking along the lines of holding a needle in place via magnets, using some other force such as air currents, or having a two-hand system that holds onto the needle one at a time.

Sorry if this isn't the right place to ask.
Thanks!

Photo
I tried posting this on r/whatisthisthing, but it got auto-removed because I already know the main object is an exhaust pipe and I'm specifically asking about the purpose of the wire assembly.

This is a large stainless steel ventilation pipe located right next to a river and a water/hydro facility in Germany. There is a wire (partially with yellow/black markings at the bottom) threaded through welded triangular metal brackets wrapping around the pipe. On the left side, there is a small white electrical junction box attached to the pipe.

Two things I have already ruled out:
- Bird deterrent: Doesn't make sense, as birds can still easily sit on top of the pipe, on the brackets, and on the wire itself.
- Lightning protection / Grounding: Doesn't make sense either, since the entire stainless steel pipe is already conductive.

Does anyone know the actual engineering or functional purpose of this setup?

Edit: okay I think the answer is the obvious "no" and I'm unwilling to sacrifice a mason jar to test it

Edit2: nevermind, I think I was right all along and it's simply everyone else who is wrong. Hah just kidding!

But I will say that I took a small expendable soda lime pasta sauce jar, filled it with boiling water, capped it, and shoved it into a yogurt container full of 32F ice water and... nothing happened.

All temperatures were verified with a thermapen one temperature probe.

But perhaps that was just luck. So I reset everything. This time I submerged the jar in boiling water to make sure there's minimal heat loss from transferring the water and capped it with mitts. And prior to this, I dumped 275g of salt into the empty yogurt container, fill it with crushed ice and some water and stirred until it became a liquid slurry at -0.4F.

And then I shoved the boiling hot jar ​into that. And...nothing happened. Additionally, and very importantly, nothing continued to happen for the next 10-20 minutes before I eventually called it as the bath had reached 32F. And interestingly, ice never formed on the inside despite no salt present inside the jar and the outside of the jar measuring 23F at one point (but the possibility of a bonus explosion via ice expansion kept it fun).

I took temp readings of the ice bath, temperature of the outside of the jar at sporadic time intervals and took pictures. That'll have to be a separate post if there's interest.

Yes yes, it's just two data points. But either this is the luckiest grocery store soda lime jar that rolled super high on thermal shock resistance at its conception, or...the boiling water protected the jar from failure.

Or idk, maybe it just stored all the energy from the explosions that didn't happen for one massive explosion at a later date.

Orig post:

(as opposed to the more obvious no-no of an empty boiling hot mason jar plunged into ice water) I remember the temperature gradient stuff from heat mass transfer but never in relation to thermal shock.

Anecdote:

Making yogurt so I was waiting for my scalded milk at 180F to cool down, got impatient, and put the hot mason jar of milk into a water bath for faster cooling. It's soda lime glass though and it got me thinking: how comfortable of a safety margin do I have here? Should I even be anxious about a possible catastrophic failure?

I work in the cannabis industry, and have recently stepped into the chemistry side of the industry with heat pressing rosin.

Typically, an industrial rosin press exerts the force directly from a hydraulic heating platen, onto a static heating platen.

Often times, personal presses (smaller than 5 ton) have problems with fully extracting all the material, whether it be from raw plant material, or solventless concentrates.

My thought process is whether some sort of ultrasonic wave generator could potentially make extraction even more consistent.

Im absolutely unsure if this concept is even possible, hence my idea in putting this thread here. If you have any kind of logistical expertise in either the rosin press field, or electrical/acoustic engineering experience, your input is highly appreciated!

Been reading a lot around compensated pulsed alternators, can’t help but realise that on paper it is better in many applications to capacitors but has not been commercialised in nearly the same way for the applications they seem ideal for

Has anyone made a compact Compulsator for commercial use cases eg EML or arc welding?

Been trying to find out about it, I know there was a post on here 9 years ago asking something similar with new advances in solid state switches now it seems inevitable that someone has built a compact Compulsator and sold it commercially, if anyone has any expertise on this please do reply, I’ve been reading as many research papers I can find about all kinds of new topologies.

I’m understanding the engineering side but not the commercial side as on paper it seems like an idea choice. Perhaps I sound stupid but I’m still early in my research

I, along with lots of other folks here, are getting hit with high electric bills and wanted to integrate a solar panel/battery to offset the costs.

I live in an apartment, so I cannot install solar into the grid, but I was wondering if I can install solar panels on the balcony wired to a battery/inverter and plugged into some sort of power sharing/combining device into our washing machine.
My goal is to provide power via the grid and solar panel offsetting the power from the grid. If the washing machine is not being used, the solar panel charges the battery. When it is being used, it pulls power from both the battery and grid.

Is there any off the shelf parts like this?

I have a background in EE, but a concentration in RF so my power background is a bit limited.

I live in a state where we have canals running over a lot of the main regions and there have been recent developments concerning installing solar panels over them.

This got me wondering about how feasible it would be to route a train over them, since canals tend to generally be straight, already be owned by the state, have little existing infrastructure, and stand on compacted ground. It doesn't even have to be directly over the canal, per-se, but use part of the right-of-way and be raised from ground level by something like 20 feet to not interfere with canal maintenance. My thought would be that raising it off the ground would be cheaper than dealing with land purchase, environmental studies, and litigation.

EDIT: I just wanted to specify that I’m specifically referring to ball bearings. I guess that wasn’t obvious from my original post.

I’ve been shopping for some bearings lately, and noticed that some open bearings specify that they come packed with grease. For example, this open NTN bearing which has the 3AS suffix, indicating that it’s packed with Shell Alvania #3 grease.

What is the point of that? Open bearings are typically installed in equipment that provides them with splash or pressurized lubrication; you wouldn’t want a bunch of grease to be flushed out of the bearing by the liquid lubricant, which would then be pumped around the system.

I know that there are a bajillion different applications for bearings in the modern world, but this is one that I just don’t understand the reasoning behind.

(Sorry if this isn’t the place for this question)

I’m a highschool student in a robotics club called SeaPerch. We have to make underwater rov’s and last year we had to pick up a relatively heavy object. We’re allowed three tiny motors and the frame of the rov is pvc. When our rov was too small it couldn’t pick up the object. When it was too large, it was severely slow. Is there a method or procedure for solving this problem typically?

Asking from South Korea. The check is still ASME B31.3.

I already checked 304.1.1 before asking.

Pressure design thickness is t = PD / 2(SE + PY). Minimum required thickness is t_m = t + c. The usual 12.5% mill undertolerance is handled by ordering pipe whose minimum wall is still at least t_m, so t_ordered >= t_m / 0.875. That does not change the pressure equation.

What I still see on field checks is people putting 1/0.875 back into t itself, before c. On thinner schedules that is what changes the schedule you buy.

If you run B31.3 wall checks: do you keep the 12.5% only on the ordered thickness, or does your practice fold it into t? Where does that split actually change the schedule?

I don't really understand fuel consumption but was considering the possibility of lowering the speed limit on highways like we did in the last fuel crisis.

Not sure if this is the place for this question but I had a bit of a shower thought.

I know electric cars operate by using electric motors to drive one or more wheels from battery power. And that in a diesel electric locomotive the “battery” is the diesel generator. Could the locomotive method be applied to a gas/diesel internal combustion engine car? It seems to me that would eliminate the need for a transmission system and would give the “instant torque” that electric cars have.

What would the drawbacks be?

There is this technology that Wright Aeronautics came up with in the 1940s and 50s, and it was produced all the way until production stopped in 1961

With the engine itself serving all the way until 1981.

It was truly special. It was not the normal turbo compounding that you are probably immediately thinking of when you think of the Volvo semi trucks, the Scania semi trucks. This is not a D13 TC because those use pressure turbines. They generate back pressure. They use pressure buildup to spin up shaft power. They gain between one to seven percent, maybe ten percent on a really lucky day of extra power. And they do that with no extra fuel consumption. But the system developed for Wright developed over 20% more power with not a single drop of extra fuel, no appreciable back pressure, and no extra controls needed with 70-year-old technology. I've thought about this for a while. I believe that it should be experimented on, well, it has, but at a grander scale, researched deeper and much more thoroughly considered for planes and automobiles and generators, all sizes and shapes.

There's a lot of research in interval compounding, but I have a feeling that it's looking at the wrong kind.

Blowdown is a different kind

What do y'all think?

And I know it's expensive, but, well, any big modification to a system of an engine is expensive. I know it's complex, but it doesn't necessarily have to be. It could be an electrical path. Plus, most major modifications to engines are complex anyway. I wouldn't consider those downsides inherent to this system

I need to build a shelf platform that can detect weight changes as low as 50g and can physically handle up to 5kg. First revision used a load cell bar and we just take the data and see if it passed a threshold. Unfortunately the shelf needs to be smaller so second revision can not use the loadcell.

FSR might be the next option but drift may make it falsely trigger if the item is on the shelf a long time. Piezoelectric sensors may be better because we really only care seeing if an object is placed or not not the value itself? So we can register the change.

My concern is can it recognize a 50g item being placed on it momentarily and would it break if a 5kg load is applied ?

So at my kid’s pre-school there is a playground area enclosed with a white vinyl double gate that is closed with a top pull latch system. The issue is that the teacher is unable to take the kids outside to the playground because she is 38” tall (literally) and can’t reached the latch. I could complain to the district or, hear me out, guerilla style modify the latch so it’s accessible.

link to what it kind of looks like:

https://cdn.shopify.com/s/files/1/0108/1652/0256/products/ML3VP-MagnaLatch_S3_Vertical_Pull_RENDER_hero_large.png?v=1555042359

So basically I was designing a cooling system attempting to do it passively using a large heat-sink.

So I bought one that had good stats more than I needed, at least I thought but it looks like I don't understand the rating system I believe.

Essentially I bought two of these aluminum heat-sinks.

https://www.mouser.com/datasheet/3/264/1/122547_Thermal_Extrusion-1664375.pdf

I cut them in half so had a little under 8" of length for the 4 sections. I thermal adhesived them all together side by side. And placed them vertically and then as a test I just wanted to see how it could handle some direct heating applied on them it.

bought some 200*200mm heating pads 45w's each and used 2, essentially one per each two blocks side by side. So 90w's and verified it was around the range, 95-89w was the range I was getting.

But from its stats in a passive natural air environment I should get a score of .32c/w. Per each. At least that is what I assumed. But clearly I didn't understand the stats.

Since .32c/w divided by the 4 8"s I have is .08c/w for the entire setup. Theoretically I should be able to handle the 400w at a 32c rise the way I read it. Technically a little higher temps since the sides are glued together

But on testing them with 90ws of heating I got a 32c rise from just the 90w's and the heat-sinks fins were fairly evenly heated from 25c to 57c off by 1c from 57-56, but mostly 57.

So just trying to understand how the rating system works.

Like looking at the above stats of the one I bought, it clearly can only handle 90w's in the manner that I got it. But how would I look at this heat sink chart and do the math to determine how many I would need for 400w's without my experimentation.

From my experiment I would need at 22.5 watts each 8" section I would need like 18 of these sections which is huge. But how would I look at the chart and get this number, so that I could then read other charts to understand them better. Since clearly I misread it.

*Added info was attempting to stay below 60c in a 25c room for example

Hello, I'm a high school student working on a small research project about reducing particle segregation during the dry electrode manufacturing process. I want to investigate how different mixing conditions affect powder mixing uniformity, but I'm running into a few problems with designing the experiment.

Since I don't have access to an actual industrial mixer, I'm planning to 3D-print a small-scale blender based on an existing design and use it for my experiments.

However, I can't use the actual materials involved in dry electrode manufacturing, so I'll need to use substitute powders or other materials instead.

I have a few questions:

1. Choosing substitute materials: What properties should I consider when choosing substitute materials for this kind of experiment? For example, would particle size, density, shape, or surface properties be important? Are there any commonly used materials that would be suitable for a small-scale experiment?
2. Measuring mixing uniformity: How could I quantitatively measure mixing uniformity using substitute materials? Would it be better to use materials with different colors, particle sizes, or densities? I'm particularly interested in methods that are feasible for a high school student with limited equipment.
3. Experimental limitations: Are there any important factors I should consider when using a 3D-printed blender instead of an actual mixer? I'm also wondering whether the results from substitute materials could tell me anything meaningful about particle segregation in dry electrode manufacturing.

I'd really appreciate any advice, suggestions, or references to relevant research papers. I'm still learning about powder mixing, so even suggestions about what to look into would be very helpful.

Thanks in advance!

For people working in manufacturing or plant operations in Germany, I’m curious about how temperature is monitored in processes like heat treatment, furnaces and production lines.

Are thermocouples and RTDs still commonly used, or are non-contact sensors and digital monitoring systems becoming more common? What tends to determine which method a plant uses?

If heat round penetrates the armored vehicle everyone dies due to hot copper and pressure increase. But how much damage is done on the other side if you hit and penetrate iron plate that is in the open? Or if the enclosed space is huge like a side of the ship?

I hate audio. I learned a bit about it in school, and I can't really explain why I dislike it so much. It just annoys me. I think audiophiles might be partly to blame, but I need to work on my relationship with music.

I'm just a poor Gen Z girl trying to detox from distractions by forcing herself to study for university. I started my first year of Electronic Engineering, and Linear Algebra is killing me while Mathematical Analysis is finishing me off.

Like most people, I enjoy listening to music, but sometimes having my computer right in front of me, with Discord, YouTube, WhatsApp Web, and everything else, makes it hard to focus.

So I want to build my own audio player. And I don't want to make a basic one. I want to give it one of those lovely e-ink displays, SD card support, no Bluetooth, rotary encoders, a proper interface for browsing and selecting songs, and all that good stuff.

I'd love to hear your recommendations for tutorials, modules, components, or anything else that might help me build this.

I'm building a transforming drone inspired by the M4 morphobot for my project, but simplified to just two modes: flight and ground mode. I know the main argument for adding ground mode is power saving. In the M4 paper, their robot consumed 3000W in flight mode but only 30W driving on the ground which is a huge 100x difference if you need to stay deployed longer or navigate indoor spaces.

The issue is I'm still really struggling to find a solid real-world application that justifies the trade-off. The morphing mechanism adds a ton of weight and mechanical complexity, which hurts flight time. Plus, ground mode is super slow. It feels like in 99% of cases, you'd be better off using a regular drone or a cheap rover. What kind of application would actually justify this design? Like a scenario where a pure drone fails AND a pure rover fails, so a hybrid is strictly required?

I've pretty much run out of ideas and I'm starting to feel like I'm building a gimmick looking for a problem. Am I cooked or is there a legit use case here?