All Questions

Filter by
Sorted by
Tagged with
11
votes
1answer
152 views

Recommended models for mineral liberation in crushers

I'm investigating comminution processes at work, and from my studies I know that there are different breakage models for different modes (Compression, attrition, fracture etc). So far I have only ...
11
votes
4answers
16k views

What is the difference between “Crushed Stone” and “Crushed Gravel” aggregate?

Crushing Question While reading a material specification for crushed aggregate, the text mentions both "crushed stone" and "crushed gravel" are acceptable. These materials sound very similar, but ...
11
votes
1answer
1k views

Observability using the Discrete Extended Kalman Filter (EKF)

I have built (several) discrete Extended Kalman Filters (EKF). The system model I am building has 9 states, and 10 observations. I see that most of the states converge except one. All except 1-2 of ...
11
votes
1answer
168 views

How do the bubble oscillations in two-phase flows affect the dissipation rate of turbulent kinetic energy?

I am investigating the effects of bubble oscillations (calculated using the Rayleigh-Plesset equation for bubble dynamics) on the turbulence in two-phase flows. Since I am using cryogenic fluids, the ...
11
votes
4answers
1k views

Preventing condensate backup at startup with orifice (venturi) steam traps on medium pressure batch process mains?

I am working with 1" medium pressure steam mains (45 psig) for a batch process. Time between batches is usually short (to the order of minutes) but depending on the day the delay can be hours, and ...
10
votes
3answers
3k views

Strength of a welded steel gate with vertical bars vs. crossed diagonal bars

Looking for some hints on how to create a rough estimate for the following problem. Given two steel gates with the same dimensions, same material - e.g. everything is the same. The only difference ...
10
votes
5answers
16k views

How to calculate lever force when lever has uniformed distributed load?

We have a simple class 1 lever: $$\begin {array}{c} \text {5,000 kg} \\ \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \...
10
votes
4answers
3k views

Are there different solar panels for recapturing energy from household lighting?

I have been investigating recapturing energy from house lighting using solar panels. Are there solar panels specifically designed to capture indoor lighting with a higher efficiency? If so, what are ...
10
votes
3answers
6k views

Why is it unwise to choose cylindrical horizontal beam

I heard that it is unwise to choose cylindrical horizontal beam. My question is why?
10
votes
3answers
2k views

Could a gold/{second metal} crown be created that would pass the Archimedes test cost effectively?

Many people are familiar with the story of Archimedes submerging a crown in water to identify if the volume of the crown was consistent with the volume of the same amount of gold. The test was to see ...
10
votes
3answers
1k views

Why were engineers negligent in the 1981 Hyatt Regency walkway collapse?

I was recently reading up on the 1981 Hyatt Regency walkway collapse. It was a tragic loss of life and haunts many to this day. The linked article does a better job of summarizing things, but here's ...
10
votes
2answers
7k views

What made bronze the first widely used (non-ornamental) metal in human civilization?

I recall learning about the bronze age in school. Why was bronze so important to the technological development of humans? Why not some other metal?
10
votes
4answers
158 views

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?...
10
votes
2answers
477 views

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 ...
10
votes
3answers
902 views

Does good electrical conductivity imply good thermal conductivity?

Typically materials which are good conductor of electricity are also good conductor of heat, and vice versa. Are there notable exceptions?
10
votes
4answers
2k views

What is an engineer's liability for code changes that occur after submitting a design?

What if any liability would an engineer have in the following situation? This is specifically in reference to engineering within the USA. An engineer produces a design and plans that meet the ...
10
votes
3answers
1k views

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 ...
10
votes
3answers
1k views

How does one go about building an underground structure without concrete?

I was reading an article that was linked on another site I frequent on "India's forgotten stepwells", which are basically elaborate wells with stairs to go down to the water level, sometimes 10 m or ...
10
votes
4answers
5k views

How would adding a wind deflector in front of roof-mounted solar panels affect drag on an RV?

I am mounting solar panels on top of a recreational vehicle (RV). To reduce drag, I was planning on building a small ramp in front of the panels to deflect wind before it hits the flat panel and ...
10
votes
2answers
2k views

Are small car engines designed to tolerate a higher duty cycle than large car engines?

For simplicity we're going to ignore aerodynamics and vehicle mass for a moment... Are small (around 1 litre) car engines designed to tolerate a higher duty cycle than large (2+ litre) car engines? ...
10
votes
5answers
1k views

How is a mechanical system designed and tested without building a physical model?

I am new to mechanical engineering, although I have a scientific background (postgrad in Mathematics), and I (mostly) code for a living. I have an idea about creating a mechanical device; I envisage ...
10
votes
2answers
973 views

What is the maximum length of oil pipelines?

This is inspired by the discussion and controversy surrounding the Keystone Pipeline. The main part of the Keystone Pipeline system is about 3,400 kilometers long, stretching across a large portion ...
10
votes
2answers
558 views

Differential equations of a (simplified) loading bridge

I am having trouble to calculate the differential equations of a simplified loading bridge. The system is build as shown in the picture below (just a sketch): If I use the Newton approach, I am ...
10
votes
1answer
15k views

What are left justified and right justified ADC results?

The TI MSP430F20XX series has a 12-bit internal ADC output, which is right-justified. What is the difference between a left-justified output and a right-justified output? What are their pros and cons?...
10
votes
1answer
1k views

How do I keep my bit from wandering on a drill press?

I punch metals before I start a bit in them, but with small-diameter bits I am finding that they wander inside the material. E.g., drilling a 1/8" hole in 1/2" of aluminum the (titanium-coated HSS) ...
10
votes
2answers
10k views

How is the design life of a reinforced concrete structure calculated?

The specifications for large structural projects typically call for the structure to have a specific design life. This can be 50 years, 100 years, etc. Accommodating the design life for steel can be ...
10
votes
1answer
2k views

Where did I go wrong conceptually when attempting to calculate the maximum force on a truss at a given joint?

In the problem statement below, the question states to find the maximum load $\vec{P}$ that the truss can support. My method of approach was: Draw a FBD for the entire structure. Generally I would ...
10
votes
1answer
13k views

What is the meaning of vorticity and circulation?

In fluid kinematics I can't understand the meaning of these terms : vorticity and circulation. Can somebody give me a description of these terms so that a lay person can understand them easily?
10
votes
2answers
413 views

Are threads machined from high tensile steel more susceptible to damage?

I have an ASTM A311-04 1.25" diameter round 1050 steel bar that exhibits a tensile strength reading of 155,227 PSI. Normally, we receive material in the 13-133,000 PSI range. The bar is machined to a ...
10
votes
2answers
1k views

How are the thermodynamics of CPUs and other chips handled?

I hear that designing the thermal efficiency of such systems is very difficult. I'm not sure why, though, and I am interested. On the one hand, I bet the heat is somehow a function of the total power ...
10
votes
1answer
453 views

Does weathering steel corrode the same as carbon steel when it doesn't develop a protective patina?

Weathering steel is supposed to form a protective patina when exposed to wetting and drying cycles. This protective patina prevents more corrosion from occurring. This is what differentiates it from ...
10
votes
1answer
167 views

Saving RAM Memory when writing to 2K page size NAND flash

I am writing a driver for the Samsung K9WAG08U1D NAND flash chip. The specification of the memory chip mentions it has a page size of 2048 bytes (2kB). I am using a ...
10
votes
2answers
29k views

How to deal with a point force acting right on the hinge of a beam?

I have been attempting to solve a question where there is a point force acting on the hinge of a beam. Here is the problem: I am not sure how to deal with the 2 kN point force at $C$ ($C$ and $E$ are ...
10
votes
1answer
3k views

How do I calculate the strength of a weld joining two crossed rods?

While considering this recent question, I started wondering how to determine the strength of the welds in the steel mesh. As AndyT points out in his comment: The welds at the connections are only ...
10
votes
1answer
2k views

Can you use the Hagen-Poiseuille equation for a pipe which radius is in the sub-millimeter region?

As this will depend on Pressure drop $\Delta p$, assume that it does not leave the range from 0 to 100 bar. The Hagen-Poiseuille equation for an incompressible fluid is defined as: $$ \dot{V} = \frac{...
10
votes
1answer
9k views

How do I batch plot drawings in monochrome without editing DWG?

I'm using AutoCAD 2015, and I run into this all the time. I'm given a group of DWG drawings, and I want to plot them into one monochrome PDF, but they do not have monochrome.ctb selected as the plot ...
10
votes
3answers
8k views

How do you determine the accuracy of a measurement device?

Lets say you have a measurement device of which you do not know the accuracy, and a reference measurement device. Both measure a variable $x$. The range of interest is $x_0<x < x_1$. How do you ...
10
votes
5answers
2k views

Low cost, moderately accurate water depth measurement

tl;dr: After an extended conversation with an old-timer, I realized a few things: The single most valuable measurement for the majority of people will be water-depth-in-well. The second most valuable ...
10
votes
1answer
216 views

What is the significance of a diagonal input in a control diagram?

I have seen several block diagrams with diagonal inputs, drawn with an arrow through the block. and others like that (via Google image search) What is difference between this and a typical signal ...
10
votes
1answer
188 views

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 ...
10
votes
2answers
237 views

What's this mystery symbol on a manufactured machine?

I hope this is the right place to ask this question; if not I'd really appreciate some tips as to where else I can go for answers. The symbol above (apologies for the blurry quality) is on a Chinese/...
10
votes
1answer
501 views

Are all pressure-volume processes polytropic?

I was searching for information about pressure-volume processes when I read, in a heat engineering book, "The process is polytropic with $PV^n = \text{constant}$." How can I know that a real life ...
10
votes
3answers
4k views

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 ...
10
votes
2answers
1k views

Soil swelling and mass/volume relationships

Given moisture content, Specific gravity of solids, initial volume, and weight. I'm asked to compute the moist unit weight, dry unit weight, and degree of saturation of this compacted soil. This is ...
10
votes
3answers
274 views

Bonding Semiconductors to PCB

I'm trying to bond semiconductor samples (Si and Ge) area ~1-2cm^2 to fiberglass printed circuit board (PCB) We use West system marine epoxy for other things. 105 resin 209 hardener (long cure time.) ...
10
votes
2answers
201 views

Best way to get rid of turbulent flows?

I am making a testing facility for pumps. This facility has to be able to handle 500 m3/h with at little turbulence as possible. The basin itself is 5 meters long, 2,5 meters wide and 2 meters tall. ...
10
votes
1answer
930 views

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 ...
10
votes
2answers
643 views

Comparing the performance of glass and granite in a heat storage application

Background I am working with a small team on a university project to build a greenhouse heat sink. This will pass warm air at the top of the greenhouse down through a chamber underground filled with ...
10
votes
1answer
893 views

Will a sacrificial anode protect any length of metal that it is connected to?

When using a sacrificial zinc anode, is there a limit to the distance that its protection will extend? The protection works based on electrical conductivity, so distance would seem to affect the ...
10
votes
1answer
615 views

How do ultrasonic proximity sensors detect motorcycles differently from cars and trucks?

My car has ultrasonic proximity sensors to help me park. I've noticed that when motorcycles whiz past me the proximity alarm goes off. I originally thought that the motorcycles were just too close, ...

15 30 50 per page
1
3 4
5
6 7
191