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What does the steel grade "11SMn30" mean?
I am starting to use steel in some of my designs, and while trying to learn more about this material and its properties I have realized that there is so much more to it than I thought.
How does the grading system used for steel work? For instance,…
jhabbott
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Can a riverboat tack upriver?
Note: This question originally appeared on the Physics site (see here) and was closed for being off-topic. Whoops!
If ships at sea can tack in a zigzaggy pattern by converting backwards force from the wind (using the sail) into sideways force, then…
Palbitt
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How is the wattage of an incandescent light fixture determined?
I've seen light fixtures with varying wattage rating. From 30W to 100W even though the actual socket is the same.
What is the limiting factor, why can't I put say a 75W bulb in a fixture rated at 50W?
ratchet freak
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At what temperature do I risk altering the structure of steel?
If I have structural or tool steel that has been treated to some standard (ASTM, SAE, ISO -- e.g., for hardness) but I don't know the details of the treatment, is there a "safe" temperature below which I can work the steel without affecting its…
feetwet
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10
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Definition of buckling as a sudden deformation
On Wikipedia, buckling is defined as follows:
In engineering, buckling is the sudden change in shape of a structural component under load such as the bowing of a column under compression or the wrinkling of a plate under shear. If a structure is…
S. Rotos
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Is it possible to "boost" a WiFi signal using an aluminum soda can?
I recently discovered that one of my roommates had attempted to boost the WiFi signal by cutting up a soda can and placing it near the router, like this:
My roommate was probably following an internet guide like this one, which advises shaping the…
hangar
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Many small bolts, or few large bolts?
I am affixing a servo motor with a machined enclosure to a base plate with drilled holes. The current design uses eight M-2.5 bolts in a figure U pattern (3-2-3) around the enclosure.
Tightening that many bolts/screws takes time, and the small gauge…
Jon Watte
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Why do we pave roads instead of making them from removable parts?
If roads were made of removable parts, we'd probably have fiber cable internet everywhere by now I'd say.
It'd be so much easier to install e.g. new electricity and water infrastructure and to maintain them if roads where made like that. We'd be…
Yuri Borges
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How is gas flow through (extremely long) pipelines monitored and controlled?
(This is closely linked with measuring the Mach number inside a nozzle but it is not regarding the supersonic flow)
Friction and heat transfer have effects on the Mach number of the compressible flow (Fanno and Rayleigh flow). As it is extremely…
Subodh
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Developing a stochastic differential equation model for concrete fibers
I am working on modeling concrete fibers (metallic fibers) as a mathematical model. My work is for my thesis. I am a PhD student of numerical analysis, but I am working on a real tunnel project.
I have had issues with the distribution of fibers in…
Khosrotash
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How do you select the correct area to consiser for first moment of area calculations?
I have just begun studying mechanics of materials and I am struggling to understand intuitively how to select the area in first moment of area calculations. I was hoping someone has a relatively easy explanation.
The problem arises when calculating…
Akitirija
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Steam sterilization of whey in a bioreactor
I'm trying to design a bioreactor to produce citric acid with whey and Aspergillus Niger.
The first step in the process would be to put whey into the reactor with some dextrose (approx. 10%). Then, this solution should be sterilized, and I was…
Pepe Mandioca
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10
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Is a permanent platform that is hanging and moving a dead load or a live load?
If a permanent room or platform is suspended from a larger structure (say, on a cable that is attached to a hook on a track in a ceiling) and designed to be in constant but not necessarily repetitive motion, does the load that the room/platform…
Matt
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What liquid crystals are used most frequently in displays?
Is there a specific chemical that is used frequently in the production of liquid crystal displays? During my internet research so far, it seems as if the specific chemical composition of the liquid crystal does not matter very much. This website…
DK2AX
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In the context of a known disturbance $d(t)$ in a control loop, what is the $\Delta t$ at which the control loop has to be executed?
As an example, consider a P-T1-system with a PID-controller. First look only at the P-T1 system, set a $y_r$ and wait a long time - then we take a look on its output $x$ and see that it has still a disturbance $d$ which variates with time (see the…
JHK
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