# All Questions

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### Do any continuously-variable-speed electric motors use Alternating Current?

All the "energy-efficient" continuously-variable-speed electric motors I've seen in consumer applications (e.g., HVAC, water pumps – all motors producing on the order of one horsepower) ...
• 1,745
13 views

### What pressure do objects at exhaust of pipes feel from flowing fluid? Dynamic or Total?

Let's imagine that we have one fluid source separated somewhere in two pipes of R1 and R2, and we put one object at exhaust of R1 pipe and one more object at exhaust of R2 pipe (R1 > R2). Let's ...
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### Calculating deflections on an inclined beam

I'm applying a force to a stepped inclined beam (that's what I'm calling it; don't know what the correct technical term would be) in which it's essentially a cantilever with the first section angled ...
• 1
1 vote
514 views

### Why bulldozers are so slow?

Tracked-type tractors and bulldozers are very slow engineering vehicles. Their top speed is less than 15 km/h and when pushing it is even lower (< 5 km/h). For example: the Caterpillar D9 top speed ...
• 111
8 views

### What are important factors to considering from heat exchanger results?

Apart from an increase in mass flow relates to which results in an increase in heat transfer, what else is important to mention about heat exchanger results?
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21 views

### Does a disk placed in a pipe perpendicular to flow direction of fluid feel dynamic pressure or total pressure?

There are two discs in the pipe but not at the same time. You can consider conditions with X but without Y, then with Y and without X. I am pretty sure that disc X will feel less force from fluid than ...
• 101
35 views

### How is a Remote Apprentice Machinist Possible?

I was researching opportunities to learn more about manufacturing and machining and found that much of the education is driven through 3yr-4yr apprenticeships. I found several postings for remote ...
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1k views

### Steel expanding in a tight space

Hypothetical question: What would happen if I were to cool down a steel cylinder to make it contract, and then slide it all the way into a cylindrical hole in a room-temperature solid steel box? The ...
• 279
21 views

### Manufacturing/Production of Spherical Lenses

How are spherical lenses cut out using a diamond tip? In this video, the lecturer says: Take a piece of glass, mount it on a rotary stage. Then bring a diamond tip near the glass and start rotating ...
• 101
40 views

### What does this line with cross means in the blueprint?

In this blueprint, there's the line with a cross with diameter of .115 at the far right side. What does this line means? Does it means that the section with length ...
• 103
24 views

### shaft connected double water wheel to lift water back in closed loop

This is meant for mechanical closed system for hydroponics. Two wheels connected by same shaft so the wheel going down lifts the water back with the other interconnected wheel to a slight incline. I ...
23 views

### Requesting Help for confusing block reduction techniques

I was solving a block reduction practice problem above. How do I collapse this block diagram from this position? I know I can swap Summation junctions, but Im stuck with the G3 branch inbetween my ...
8 views

### Determine shockwave location in Ansys Fluent

how can I find the shockwave location in Ansys fluent for an aerofoil please? I couldn’t see a shockwave location option in the plots but I’ve seen it being plotted in papers, so it must be possible?
15 views

### What is exactly dead-burnt lime, and why is less reactive than quicklime?

When producing lime on a lime kiln, there exists the possibility of overburning the original limestone and producing the so-called dead-burnt lime, with a much lower reactivity than quicklime. Some ...
50 views

### Mechanism for fast vibration

What mechanisms can be used to apply fast vibration to an object? One way is this. What are some other ways to do it? I'm looking to go as fast as possible - 100s of Hz if possible. Thankyou
15 views

### Prove a formula for void ratio that depends on saturated, dry and water unite weights

I don't know where else to post this. I am reading a Geotechnical engineering textbook by B.M. Das, 6th edition. Problem 3.1 is as follows: For a given soil, show that e=\frac{\gamma_{sat} - \...
32 views

### Importance of mass flow rate on the overall heat transfer coefficient

As mass flow rate increases so does the heat coefficient. Is there a way to directly relate this? Is it because of the flow going from laminar to possibly turbulent also help increase heat transfer. ...
• 1
26 views

### What is the equivalent rotational/angular stiffness of a beam

I'm trying to model a larger system and working through a conceptual issue. I'm familiar with the concept of expressing the stiffness of a beam as an equivalent spring stiffness like in the image ...
19 views

### If mass m undergoes a downward displacement x, determine the oscillation frequency of the disc

Mass m is suspended from a rope to a homogeneous circular disk of mass mc and radius R, as illustrated in Figure. The disk is restricted from rotating by a spring attached to it at a distance rc from ...
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30 views

### Why is the vector cross product different here?

I was taught that the linear velocity of a body rotating around a fixed axis is the cross product between the angular velocity and the position vector. The vector for the velocity here in this picture ...
• 1
1 vote
22 views

### Torque for rotating base

I'm designing a simple robot arm but I don't know how to calculate the torque of the rotating base for the robot arm so I can choose the right gear ratio for the stepper motor that will be in the base,...
24 views

### If the diameter of a hole, and the diameter of a shaft are exactly equal. What kind of fit is that? ISO 286-1

It's pretty intuitive to understand clearance fit, if there's space between a hole and a shaft, it's a clearance fit. Meanwhile, if a hole and a shaft do not fit (or interfere) it's an interference ...
30 views

### Heat exchanger analysis

Hi i have an task of calculating the rates of heat transfer for hot and cold water and discuss the discrepancy's. There are three tests with each one increasing flow rate of the water the same for hot ...
• 1
16 views

### 2. Determine the rotation (the slope) and deflection at points B and C on the beam loaded as indicated in Figure Q2. (i) Using Moment-Area Method [closed]

[![Structural Analysis][1]][1] [1]: https://i.stack.imgur.com/C3VPS.jpg please can you solve in within 31 minutes. Thanks
28 views

### Integrating the Onsager formulated mass transport equation for a binary mixture

I want to develop a model for the Maxwell-Stefan mass Diffusion for a binary mixture for a nano porous membrane. I have permeation data and adsorption isotherms measured I just need to implement the ...
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14 views

### Is the a similar method of calculating moment in inelastic bending like in the case of torque for inelastic torsion?

When calculating for Torque in torsion or for Moment in the case of bending, the concept is usually first introduced with the simplification of the assumption that the stresses and strains are in the ...
22 views

### How to calculate the force required to move this pawl that swings on a pin?

The structure (pawl) is rotating about a pin and is pushed forward by a spring. I want to calculate how much force it requires to push the pawl forward with the spring. Since the spring is only ...
37 views

### What is the suitable multiplier for all units?

I create Auto CAD Drawing using Primary units decimal (mm). I need to add alternative unit as Architectural. What is the suitable multiplier for all units? After adding new value
54 views

### Trinity Lake Leak

Why was Trinity Lake's control regulating discharge increased from 0 to 1,477 CFS on March 6 .. 20, 2023? (During historic drought in California.) What is "control regulating discharge"? It ...
12 views

### Why is my SOLIDWORKS background black?

my solidworks background (where we do the modeling like drawing a line or a circle) and all the buttons (like close or minimize buttons) are black . they are there and I even can click on them and I ...
18 views

### Torque created at bottom left corner due to torque in centre of 2D box

If I have a 2D box with uniform mass of width $w$ and height $h$. I apply a torque $\tau_O$ to the centre of the box, labeled $O$. The box has a fixed point $A$ at the bottom left around which it may ...
• 1
14 views

### Can one refer to perpendicularity in GD & T system using degrees?

I am studding machine element design and drawing and I have this question. Can one translate between GD & T perpendicularity indication to something in degrees? I saw the following picture in the ...
35 views

### How does the hydraulic valve system work in excavators?

There are many types of valves used in excavators. Two are important: the main valve and the pilot valve. Is the pilot valve is controlled by the operator and the main valve is controlled by the pilot ...
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1 vote
43 views

### Advantage to reduced diameter where a gear will mount to shaft?

I will be mounting a sprocket gear on the 2 inch input shaft to my custom piece of industrial machinery I am preparing. The sprocket gears are available in 1 15/16 and 2 inch bore diameter. Would ...
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21 views

### Failure of component due to natural frequency vs stress

lets take a component like a fan blade as an example. Is it right to conclude that it will fail even when the stress is within permissible limits but its operating frequency is close (close enough ...
1 vote
57 views

### Doubt related to S-N curve

S-N curve is drawn from the results of fatigue test and fatigue test is conducted under completely reversed bending stress condition on a standard specimen. Is there any reason for conducting the test ...
• 375
43 views

### What is the name of this power connector used in the USS Yorktown?

I found this in the USS Yorktown aircraft carrier (it’s open for public tours) I know it’s a 3 phase connector of some kind, but what type of plug connects to it? Is it a nationwide standard or ...
• 103
51 views

### What happens if we have a rotating shaft with high RPM but very little torque?

If there are heavy components mounted on it, what will happen? I think it accelerates very slowly, but reaches at the highest RPM at the end because torque is equal to angular acceleration * moment ...
• 101
41 views

### Post and steel rope framework for grape vine

I am planning to build a framework to support a grape vine above a patio. Ideally I would like to use steel rope to provide this framework, rather than a full timber frame. Diagram attached. There is ...
16 views

### how big of a base do you need to support a 6' post

With a floating base what is the size and weight that you would need to support a 6 foot post that needs to handle hanging 300 pounds on it.
32 views

### Best method to mount electric motor for chain drive for industrial machinery

I want to use this electric motor to run an industrial machine via ANSI roller chain. In the images most of the machine is not visible, only the sprocket on the input shaft and a bit of the relevant ...
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32 views

### NOx emissions in diesel engines

What are the specific challenges and potential solutions for reducing NOx emissions in diesel engines without sacrificing fuel efficiency, considering the trade-offs between various aftertreatment ...
• 387
27 views

### Ideas for running 2 gas engines to 1 shaft with pulleys

First time posting, but love the forum. Hopefully this hasn't been asked before. I could only find the question in relation to electric, not gas engines. I own a pressure washing business, and my ...
17 views

### Mass and Tension in a Pulley System

I found the value for M2, unsure how to proceed from here. I got a wrong answer for T.
9 views

### Capture an Impulse (As Opposed to an Impulse Response)

I want to see if there's a method by which you could capture the characteristics of an impulse source, rather than the response of the system to the impulse. Normally, when attempting to capture an ...
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71 views

### How long a spiral copper tube would need to be in a monotube boiler in order to achieve 0.02 kg of steam per second?

So, I'm trying to calculate how much fuel/energy I would need to input in a homemade monotube steam turbine engine in order to achieve 15hp (11kw), the idea is that the engine will run at this ...
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8 views

### How to use a high current 2 Second current pulse to actuate a servo - First year Electrical Engineer

I am using a dual deployment system controller, an Eggtimer Quark REVC2 which at apogee outputs a high current 2 second pulse. I don't have time to buy a more advanced Eggtimer which outputs proper ...
19 views

### Will a thin overcoat of silicone sealant protect a non-waterproof adhesive underneath?

I'm trying to bond PMMA to Nylon-6 for a submerged application, and the only thing that I've found that will reliably bond these parts is a 2-part polyurethane. (No epoxies work, I think because of ...
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30 views

### Rotating a series of lights such that each one rotates more than the previous one

I want to rotate a series of lights that are all spaced evenly from each other with a single actuator such that when the first light rotates 1 degree, the second one will rotate 2 degrees and the ...