# All Questions

7,348 questions
1answer
12 views

### What size aluminum beam and cable do I need?

I am building a small project at work and need to figure out what size beam I need. I am basically building a wall mounted jib crane. The beam will be anchored to a wall on one end and will have a ...
0answers
16 views

### Boundary conditions in a heat transfer problem

One end of a small insulated rod is attached to a support which is maintained at a constant temperature of 473 K,and once the rod has reached a uniform temperature in its entire length the insulation ...
0answers
10 views

### Is there a technology capable of disabling the whole Earth's satellitle network? [migrated]

Machine-based communication (and navigation) relies extensively on satellites. In the future, with the massification of 5G, more and more reliance will be put on satellites (e.g. the Internet of ...
0answers
4 views

### How design the framework of a ugv robot [on hold]

I'm new to robotics and it would be very helpful if I could get some tips and resources on designing the baseplate and the framework of the ugv. I would like to construct a differential drive robot ...
1answer
22 views

### Designing cylindrical cam

So I need to design a cylindrical cam (aka barrel cam I think). I'm an aerospace engineer so I've never had a course on cams/gear design (wish I had though). Is there a general equation for the curve (...
0answers
12 views

### stiffness factors for symmetrical beam (Moment distribution method) [on hold]

would my stiffness factors for KBC AND KCB be 2EI/L OR 4EI/L ,please see beam below
0answers
14 views

### Solidworks export the 3d points of a spline

Is it possible to ( how do you ) export a series of points along a spline. A spline has been created in 3d from various segments. I would like to export a table of 3d points along the spline starting ...
0answers
15 views

### Measure distance between a circle and an ellipse center in autocad/inventor

I am working on a robotics project, I got a SolidWorks sldprt/step model of the robot(cca. 40 solids). However, I have only Autocad/and Inventor available. I need to measure a distance from n ellipse ...
1answer
13 views

### Software supporting geological analysis, design, and construction phases of a large bridge [on hold]

What software would you use to design a large bridge in its entirety. Also, how would you go from the design to having the bridge implemented. I mean someone needs to make stamps or something for the ...
1answer
12 views

### Explain how the top gear ratio is achieved [on hold]

With refernce to a four speed gearbox ,explain how the top gear ratio is achieved.
0answers
7 views

### ANSYS Fluent - Using Patch to set initial conditions, should I set the pressure and velocity or only one property to generate shock waves in a pipe?

I am fairly new to CFD and I am working in ANSYS Fluent. I am trying to model two specific shock waves in opposite directions in a length pipe. The shock waves need to be traveling at specific Mach ...
1answer
9 views

### Stepper motor torque calculation based on pulleys ratio

Say a stepper motor has fixed value of "units", given as a holding torque related to distance of the center of its shaft. Like 1kg/cm or 14oz/inch. I have a GT2 16-...
1answer
22 views

### Installing satellite dish to point to local zenith

After receiving help on my previous post (Stopping/reducing wobbliness in threaded rod), I've decided to come back and ask another question: how can I actually hold the satellite dish into place? I ...
0answers
11 views

### build a 9 volt truck bed that can tow a weighted trailer over a distance of 30 cm using pulleys and gears [on hold]

My challenge is to build a battery powered (electric) pickup truck complete with a truck bed/box that can tow a weighted trailer over a distance of 30cm. The goal of this challenge is to determine how ...
1answer
25 views

### Is thermodynamic data of fresh water a good approximation for saline water?

I am currently working on desalination project for my final year. The design is based on flashing of hot liquid in low pressure vessel and then condensing the extracted the steam to produce pure water....
1answer
26 views

### What type of bearing used in swivel arm?

To model a swivel arm on column that rotates by hand What type of bearing should i use Should it support radial and axial load or just supporting axial load is enough ?
0answers
13 views

### Can you help me with a flow rate question?

How many gallons of water (70 degrees F) can flow thru a pipe diameter (I.D. 0.475") at 50 psi over a 30 foot length in a 24 hour time frame?
1answer
24 views

### Can I use grout as mortar?

I have one tile that came off. I got a replacement tile, and some grout. But the online guides say you need mortar to glue the tile to the ground. Can I use the grout as mortar? I want to save money ...
1answer
22 views

### Pressurization Shock vs Slow Pressurization

I've looked through the engineering stackexchange and I'm still perplexed by this. Is it the same to pressurize a vessel extremely fast as oppose to real slowly? Doesn't the shock cause some spike in ...
0answers
9 views

### Calculating cooling power for server room

I'm trying to calculate how much cooling power I need to keep a server room (about $60 m^2$ with $3m$ height) in 25℃. How exactly I should do this calculation? I summed up wattage of all ...
1answer
26 views

### Scalable alternatives to CNC router and laser cutter

I am doing calculations on costs for alternatives for manufacturing this children's toy I invented, a puzzle where letters in plastic fit into wood: I have been using a CNC router to carve subtract ...
1answer
35 views

### Stopping/reducing wobbliness in threaded rod

I am working on a 1.5-meter satellite dish with a custom receiver cantenna-like feed. The dish didn't come with feed arms, so I need a way to hold the feed into place. What I tried was using a 1-meter ...
1answer
25 views

### Mechanical vibration: 2 springs attached horizontally to a wheel at a vertical distance a above the center, find the natural frequency of the system

Context: introductory mechanical vibrations, 300-level engineering. ISBN13: 978-0-13-287169-3 See problem solution below As seen in the "Potential Energy" section, the author writes that the ...
0answers
22 views

### Would an afterburner on a turbine drastically improve acceleration lag?

A little bit of context. My friends and I were watching the "Dark Knight Rises" and a discussion about the Batmobiles ensued. I, being a former ME student, said it was stupid that batman has a turbine ...
0answers
14 views

### Is critical resolved shear stress the same thing as yield stress?

Dealing particularly with the Hall-petch equation, I want to know if the Critical resolved shear stress is the same as the yeild stress. I'm trying to make heads from t
0answers
19 views

### How do I calculate the radial force on an eccentric shaft?

I have a motor driving a gear that uses and eccentric shaft and I want to know the radial force on the motor. For simplicity the motor is outputting 1 Nm of torque, eccentricity of 1 mm, and ...
0answers
28 views

### Mass of falling weight required to move gravity powered cart [on hold]

I am trying to determine the mass of the weight I need to use to propel a cart. Attached is my initial drawing of some of the forces. From this drawing, you can see that the rope passes over 2 pulleys ...
2answers
64 views

### Rapid Pressurization of closed containment

Will a 2 liters steel pressure vessel with a vent hole 1.5 cm across made for the gas outflow still catastrophically fail if 680 g of gunpowder is detonated in it? Wall thickness: 4 mm Surrounding ...
2answers
64 views

### How to determine the time it'll take a mass of aluminum to absorb a specific amount of heat from a gas flowing through an undulating cavity in it

I'll like help with calculating the time it takes a mass of aluminum block with an undulating channel through it to absorb heat from nitrogen gas at 300°C flowing through that channel. On the flip ...
0answers
16 views

### Converting ACFM to SCFM

I'm looking for the derivation of the equation used to convert ACFM to SCFM. I keep seeing $\dfrac{P_1V_1}{T_1} = \dfrac{P_2V_2}{T_2}$, but how do you derive that?
1answer
23 views

### How to estimate a ship speed based on weather conditions?

I have data from some ships, basically the base speed for a list of RPM. But it is know that this speed is not constant and it will change mainly based on whether and load of the ship. Is it any rule ...
1answer
22 views

### How does concrete perform in an Insulated Concrete Form (ICF) house?

From: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4033560/ I can see that concrete can really go bad after a few hundred freeze and unfreeze cycles: If an ICF house has insulation from the inside ...
0answers
6 views

### CLTD values in Q=U.A.CLTD? [on hold]

Does anyone have a simple explanation on where to get and how to use CLTD values in Q=U.A.CLTD?
0answers
13 views

### Petroleum/Reservoir Engineering: Estimating Cumulative GOR (Gas Oil Ratio) & Cumulative Oil Production

I have a data set from producing oil/gas wells from multiple (separate) drilling locations. Note that a given well can either be conventional or unconventional. Overall, the data set retains info ...
2answers
23 views

### What is the engineering way to describe a factory / manufacturing plant system in a formel and mathematical way

I am interested in mathematically describing as well as formalising a manufacturing plant so that other people in the engineering field understand how the system works. I am not from the engineering ...
0answers
19 views

### Is the combination of blocks and lines in this old, very long telescope an implementation of some named structure or technique?

Below are two cropped views of "Johannes Hevelius's 8 inch telescope with an open work wood and wire "tube" that had a focal length of 150 feet to limit chromatic aberration." from Harvard University, ...
0answers
22 views

### What motors to use to guide tape with high speed

My field isn't dealing with motors and such at all, however, I now need to build something that controls two motors. So I have two guiding reels with tape between them, similar to old tape recorders. ...
0answers
4 views

### how to get laminate stiffness matrices (ABD) in APDL ANSYS

I am trying to perform structural analysis of composite pressure vessel in APDL/ANSYS. I have completed the solution and now I want to extract ABD matrix.Do anyone have an idea about this?
2answers
23 views

### corrosion in electrical parts and wiring

I work in a pharmaceutical plant where saline solution is produced and bottled. The environment has to be clean (by pharma standards), which rules out many greases and other protective coatings. As ...
0answers
12 views

### digital signal processing [closed]

Kindly provide steps Examine the following systems with respect to the properties below : static or dynamic linear or nonlinear time-invariant or variant causal or noncausal stable or unstable
1answer
31 views

### Reverse vs Drive When Slipping Backwards

I was trying to drive up an icy hill with a front-wheel-drive car (2006 Honda Civic Hybrid) when the front tires lost traction and the car started to slide backwards. The car then easily spun sideways ...
0answers
23 views

### How to slide 2 small pieces of metal into each other

I'm trying to build a keyboard addon for my smartphone (https://gitlab.com/xengi/mkbd65). The last challenge I'm facing is how the two pieces, namely the smartphone and the keyboard should slide back ...
0answers
8 views

### Extrapolating BHP values for fixed speed and impeller diameter

currently i have a composite pump curve (RIGHT) where the BHP lines are embeded in the performance curve. I would like to extract out the data and create a graph of BHP vs capacity shown on the LEFT. ...
1answer
22 views

### How are circular portholes mapped onto cylindrical hulls?

When portholes are put into a cylindrical hull, such as of a submarine or an airplane fuselage, is the glass window curved to match the curvature of the cylinder? And if so, is the porthole wrapped ...
0answers
16 views

### What states other than California require less than 4 years of experience in order to obtain a PE license?

Do any states other than California require less than 4 years of experience to become a registered Professional Engineer?
1answer
21 views

### Sonomotors, Sion: Can this electric car really charge up to 30km only from its solar cells?

Maybe you have heard about Sonomotors and its futuristic electric car, the Sion. If not, here is the link to its website: https://sonomotors.com/ Anyway, the manufacturer claims that this car can ...
3answers
30 views

### Max Lift to drag ratio

I have a question that I can't solve. Coefficient of drag= x, Coefficient of Lift= y, it is given that x= 0.015 + 0.05*(y^2), FInd Max Lift to drag ratio and I know that Lift to drag ratio is L/D= ...
0answers
11 views

### What is the difference between q and u in Darcy's law

I am unable to make the distinction between the 'flow terms' used in darcy's law. Sometimes I see the law expressed with 'u' which is meant to represent 'darcy velocity'. Some times I see it expressed ...
3answers
43 views

### Strength vs. Hardness vs. Toughness

for this question: "What is the difference between strength, hardness and toughness in materials?" i have searched and have found these following definitions Strength refers to resistance to ...
0answers
18 views

### Communications Question: Resource block parameters?

I am modelling a network using MILP/AMPL; in this network there are a multitude of UEs and 16 basestations (BS) (4 macro cells, 12 small cells). Each BS has resource blocks (RB) consisting of 12 ...

15 30 50 per page