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4 votes
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In marker pens, why does the ink travel to the nib?

the fibers forming the pen filler are less densely packed than the fibers forming the nib, which extends into the filler a significant distance. This creates a capillarity gradient wherein the nib ...
niels nielsen's user avatar
4 votes

In marker pens, why does the ink travel to the nib?

In short, capillary action. The fibrous content of the tube is literally designed to be saturated by the nib dries out creating an imbalance in fluid pressure leading to ink flow towards that ...
Rhodie's user avatar
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4 votes
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How to get a wheel pump to deposit water near the top of the wheel?

Consider an alternative to the current placement of the cans. The image above from the Pinterest web site, UN Food and Agricultural Organization shows a wheel in which the cans (bamboo tubes) dump ...
fred_dot_u's user avatar
  • 7,055
4 votes
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What is the function of this device in the middle of the man-made lake?

It is an aerator for the pond. They use them for oxygenating the water and for circulation. Link to the Pentair model in picture
jwlinno's user avatar
  • 56
3 votes
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Will an electric water pump has slower flow if it must pump through a longer tube?

Theoretically, yes, but practically ,no. Regular 1" PVC will have very little flow restriction compared to the strainer and flex suction tube. Suction restrictions are always more important. And ...
blacksmith37's user avatar
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3 votes
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Can PWM be used to control the flow of a solenoid valve?

It is possible to modulate the drive of some types of solenoid fluid valves to ultimately regulate the pressure of the fluid at their output port. I have designed a product that does excatly that. ...
Olin Lathrop's user avatar
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3 votes

How can I improve water flow within this diagram?

I am assuming that your question is "how to increase the flow rate" and that your pump is a centrifugal pump. For centrifugal pumps, the flow rate out of the pump is dependent on the pressure at the ...
abqsteve's user avatar
2 votes
Accepted

How do I measure mercury in a graduated cylinder?

You need to measure from the top of mercury column, in tubes that are wide enough to allow a flat area of mercury on top and ignore the lower level along the perimeter where mercury is repelled by ...
kamran's user avatar
  • 22.2k
2 votes

Is there a type of check valve that allows gas to flow in both direction but stops liquid from flowing back?

If the flow rate is low for the gas then a ball that floats on the liquid will work - similar to how most wet vacs stop liquid getting into the motor...
Solar Mike's user avatar
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2 votes
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Is there a male and female valve that is closed until connected together?

There are many, many different commercially-available designs of fluid connectors that shut off automatically when disconnected and open up when connected. They are available in plastic and metal, ...
niels nielsen's user avatar
2 votes
Accepted

Liquid Level Control System Resistance

I'm an electrical engineer so this problem looks to me like an RC (resistor-capacitor) discharge. In the case of a resistor discharging a capacitor the time constant is given by τ = RC. In your case C ...
Transistor's user avatar
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2 votes
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Water dynamics in aluminum pipeline for dummies

The terms you are looking for are Major and Minor pressure losses. Which are a misnomer for systems on the scale your are talking about, since "Minor" losses are usually the greater. The ...
RC_23's user avatar
  • 831
1 vote

How does shear/viscous stress change in liquids as applied shear force is changed?

The way I understand it, is that (at least in laminar flow) viscosity is proportional to the "stickiness" between the layers of the fluid. I.e. higher viscosity, means that if a layer starts ...
NMech's user avatar
  • 24.3k
1 vote

Materials that will block water but allow sound to travel through without being muffled

The easy solution is as follows. Get you the cheap, thin white trashbags as used to line kitchen wastebaskets. This material will attenuate sound very little. Now note that what attenuation there will ...
niels nielsen's user avatar
1 vote

Can saline water be used in a hydro storage system and would the ambient temperature or higher liquid viscosity affect performance?

NOT a hydroelectric engineer, but I have spent a lot of years developing fluid systems using saline and related liquids. To answer the basic question: yes saline works for hydro storage systems. But ...
PatMc's user avatar
  • 109
1 vote

Optimized water droplet formation

There is research on the impact of water droplets on deep liquids and solid surfaces. It seems the most significant factor in the outcome of the collision and its rather short span, in the range of a ...
kamran's user avatar
  • 22.2k
1 vote

Peristaltic pump - theory vs reality, where is a problem?

You can't test a liquid pump with air You also didn't specify if the pump is self priming, and if it is, what is the lift it can achieve. But even if it is self priming, the amount of liquid you move ...
Tiger Guy's user avatar
  • 6,813
1 vote

Determine the length of the tube

If the flow rate is 5ml/min, and you want to know how long a tube it will take 1 min to pass through, you’re effectively asking how long a tube contains 5ml. Volume of a cylinder is $\pi*r^2*h$. 5ml ...
Jonathan R Swift's user avatar
1 vote

Is there a type of check valve that allows gas to flow in both direction but stops liquid from flowing back?

A "steam trap" should do what you want. There are a few types with different characteristics .
blacksmith37's user avatar
  • 6,134
1 vote

Is there a type of check valve that allows gas to flow in both direction but stops liquid from flowing back?

Any form of gravity trap. For examplea piece of vertical pipe with a large enough diamter will work - liquid gathers at the bottom, diameter need to be large enough to let bubbles pass through the ...
mart's user avatar
  • 4,781
1 vote

Which materials we can use for storing liquid nitrogen?

If you like living, do not attempt to build your own high-pressure LN2 tank if you have never designed commercial-grade pressure vessels before. Use this.
Austin Prater's user avatar
1 vote

Can PWM be used to control the flow of a solenoid valve?

Yes, you can control flow/pressure with an on/off solenoid, using electronic PWM. EPRs such as these from SMC do exactly that. The lifetime of the valves in # of cycles needs to be considered, as well ...
River Weiss's user avatar
1 vote

Mirror-like reflective liquid crystal display panel

If you are looking for an individually-addressable mirror array, a Digital Micromirror Device (DMD) is what you are looking for. It is used to adjust the brightness of pixels inside a DLP projector by ...
dasboot's user avatar
  • 21
1 vote

Is it possible to "pump" a powder?

We have dry cement bulkers truck running on local roads, feeding dry cement to mixer factory where it is turned into wet mixed cement. Pump air into the truck to 'blow' cement out. This video shows ...
EEd's user avatar
  • 129

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