Winuit

u/Winuit




I have been wanting to try this and see 2 options.

One way could be by attaching a motor to the shift cable (ditching the actual shifter), and have some kind of ratcheting system that clicks into place with each gear as it turns, I could have it shift according to wheel/crank speed?

Ideally it would shift in accordance to how hard it is to turn the cranks but I have no idea how to do that.

basic drawing http://imgur.com/h98VrDL .

My 2nd idea is to have a motor that moves linearly to move the derailleur back and forth along the sprockets but sounds much harder than the first.

Any better ideas/suggestions? I'm doing this with an arduino.

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r/LumiaLovers•

Thinking about getting a lumia 930 tomorrow for the good processor, hd screen, camera, and microsoft office. Wondering if there are any downsides to this seemingly wonderful device

edit: bought one. It's incredible

520

Air with volume 0.45m^3, pressure 1.1MN/m^2, and temperature 36 deg C has 2.7MJ of energy supplied to it via heating at constant pressure.

The air is then allowed to expand to a volume of 1.8m^3 according to the law pV^1.4 = a constant.


Sketch the two seperate processes on a pV diagram, then for EACH process calculate:

a) The final temperature
b) The work done
c) The change in internal energy

For air, take R=8.314 J/mol.K and molar heat capacity at constant volume Cv=20.8 J/mol.K


So i'm guessing the sketch is something like this? http://imgur.com/yHOlXHC

I'm very lost on calculating a,b,c

112

Incompressible oil with density 850 kg/m^3 is pumped through a cylindrical pipe at a rate of 9.5L per second.

a) The first section of pipe has a diameter of 8cm. What is the flow speed of the oil? What is the mass flow rate?


So i know that the volume flow rate= dV/dt = Av, so v= (dV/dt)/A.

Now the book example works it out with dV/dt equal to (9.5L/s)(10^-3 m^3 /L)

why is dV/dt not just 9.5? I'm confused why they are multiplying by (10^-3 m^3 /L), and my answer is out by a factor of 3 because of this

75

There are 2 questions from my hw I'm struggling with:

Clearly state any assumptions being made.

  1. A quantity of unknown gas which is a compound of carbon and hydrogen fills a rigid vessel of volume 3.75m^3. Mass of gas is 8.63kg, pressure is 190kPa and the temperature is 25 deg celsius.

determine:

a) The value of the gas constant (by calculation from the information given)
b) the molecular mass of the gas
c) the likely chemical formula and name of the gas


for a), my book says that for an 'ideal' gas where the equation pV=nRT holds true for all temps and pressures, the gas constant is always R=8.314472 J/

36


r/IWantOut•

I'm looking to move to BC/Alberta after my undergrad is finished and was looking for some insight from people who know about the immigration process.

My plan is to study a masters in mechanical engineering in Canada (UBC possibly), and then look for employment straight afterwards. The Canadian immigration website seems to suggest that gaining residency is relatively easy after studying there(?) Is this the case?

If I manage to secure a job for at least 1 year then it seems I can apply to Canadian experience class. Are the chances of me getting to this good or bad?

Any more info would be appreciated.

22

r/UBC•

I'm thinking about what I'll do after completing my undergrad in Scotland which is a bachelors in mech engineering, and considering a mechanical based masters course at UBC.

My plan was to complete the masters, and then looking for employment in the oil and gas sector afterwards. What are other students experiences? And how difficult is it to obtain a work permit and employment in Canada after this kind of degree?

05