A Few Questions!!!!!!! (1 Viewer)

[ALL4GOD]

Howdy Partners!!
UM i've just got a few questions, that i came across...and any assistance would be muchly appreciated!!

Firstly i was wondering, unless specified should we take "g" or "a" as 9.8 or 10?

Secondly, in basic terms, whats the diff. between "Duralumin" and "Alclad"? - i know that Duralumin is Pure Al. + 4% Copper, and that Alclad is Pure Al. + Duralumin that is pressure welded together....but yeh is that correct - and whats the variances in properties etc.?

Thirdly, Whats the differences between "Slip" and "Twinning" - as in both "Annealing" and Mechanical Twins"?

Fourthly, in telecommunications - does "U.T.P" stand for "Un-Shielded Twisted Pairs" or "Un-Twisted Pairs" - because i think ive seen both?

Finally, when you do like civil mechanics and all that - as in the forces in the members of bridges and the likes - how do you know whether the member is in tension or compression?

Well, thanks heaps for u help-a-mus Maximus!!!

Good Luck in the rest of your exams!!

Your Amigos, Craig.

 

[McLake]

Firstly i was wondering, unless specified should we take "g" or "a" as 9.8 or 10?

10

Secondly, in basic terms, whats the diff. between "Duralumin" and "Alclad"? - i know that Duralumin is Pure Al. + 4% Copper, and that Alclad is Pure Al. + Duralumin that is pressure welded together....but yeh is that correct - and whats the variances in properties etc.?

Have no idea ...

Thirdly, Whats the differences between "Slip" and "Twinning" - as in both "Annealing" and Mechanical Twins"?

?????

Fourthly, in telecommunications - does "U.T.P" stand for "Un-Shielded Twisted Pairs" or "Un-Twisted Pairs" - because i think ive seen both?

Not sure ...

Finally, when you do like civil mechanics and all that - as in the forces in the members of bridges and the likes - how do you know whether the member is in tension or compression?

By seeing which way the other reactions are acting. (Get me to explain that if that is unclear)

 

[sensual dave]

1) Suitable to use either if not stated in question. If you use 9.8 then write at the top assume g = 9.8
2) Hint - what property of pure aluminium would you want to incoporated with duralumin to get ALCLAD.
3)???
4) untwisted pair is just called that. UTP stands for UNSHIELDED twisted par
5) Assume sense as either tension or compression ( ie. away from or towards the join ), then use that sense in moment calculations. If answer is +ve then assumption is correct, if answer is negative then it is the other one.

 

[MoNNiE]

i get ya craig...sorry i wasn't home, went for a run... (for 2 hrs..?!)
since everyone doesn't understand what you mean by 3! i'll attempt to answer it
slip and twinning are two plastic deformation types that occur in metals
twinning is where the grain within the metal distorts itself at an angle ( like creasing a piece of paper into a fan) you can find this in annealled brass and i think also in colded worked brass (or is it cold worked annealed brass..check i could be wrong!).. it's representation within the microstructure consists of some thin and thick lines
slip deformation occurs along the planes with high atomic density... that is when there is a gap within the structure.. by moving two plans in opposite direction where the disslocation exists, they fill in these..umm these voids..
i really hate slip so i can't give a somewhat book definition
if i can recall.. they should be in the first set of notes the teacher gave us.. from last year!

since i'm still here i'll try #2
craig why wouldn't we use pure aluminium by itself!
if combining two different things together (like composite materials) your trying to get desirable properties out of each other. in the case of pure aluminium, it has better corriosion resistance then duralumin however it has low strength. on the other hand duralumin has high tensile strength ( better then mild steel).. thus! through pressure welding they incorperate both properties within the alclad --> very important in aircrafts! (where the pure Al is exposed towards the outside and the duralumin is internal to take all the stress)

hopefully i answered the two questions correctly!.. but anyways.. for reassurance.. consult Mr. Z! or the text book ..( for the second question look in personal and public transportation and aeronautical, there is only a small amount on it and the third.. it is located in the prelim book)

good luck!
see you on Friday!

 

[ALL4GOD]

wow - sik thanx heaps everyone!!

Umm jus one thing...i still dont get the untwisted pairs bit?
So "UTP" stands for "Un-Shielded Twisted Pairs" and STP stands for "Shielded Twisted Pairs" - but why would u not want 2 "Shield" them - cause wouldnt it be more likely 2 be damaged and more susceptable 2 interferance - without the shielding?

MMM - anyways - thanks again - Caoi For Now

 

[ALL4GOD]

ahhhahaa!!
its all good in the hood!! - i jus read one of the previos posts - and found that they are both shielded - however UTP's are shielded with plastic (polymeric insulation), and STP's are shielded with a metal foil insulator - nice nice...
hehe im understanding it now~!

Well thanks again - and Good Luck 4 Friday everyone - Cya then Monica!!!