Things you always wanted to know the answer to [Vol. 2]

[lord trumpton]

Justin Cyder said:

StevieBee said:

Why don't pilots or cabin crew suffer from jet lag...or do they?

Oh yes they do. I once went out with a BA cabin crew girl who would regularly fall asleep in the pub, restaurant, anywhere.

On second thoughts, maybe I'm just really, really boring.

Sorry, what was that?

[MissChief]

lord trumpton said:

Justin Cyder said:

StevieBee said:

Why don't pilots or cabin crew suffer from jet lag...or do they?

Oh yes they do. I once went out with a BA cabin crew girl who would regularly fall asleep in the pub, restaurant, anywhere.

On second thoughts, maybe I'm just really, really boring.

Sorry, what was that?

In seriousness, I'd imagine if they're doing long haul flights in and then Out relatively quickly they would probably try and stay on UK time (or wherever their home is) otherwise they get so completely confused their body clock would scream 'sleep!' At 3pm local time. Would make it a bit difficult for departures in far away places I admit.

[mug81]

Do banks really charge small retailers 50p for a debit card transaction? It really irks me (much more than it should)

[juan king]

What are the vents for? Seen on the front corners of most tractor units

[CraigyMc]

mug81 said:

Do banks really charge small retailers 50p for a debit card transaction? It really irks me (much more than it should)

It's more like 10p. Credit cards are usually a percentage.

[leafspring]

CraigyMc said:

mug81 said:

Do banks really charge small retailers 50p for a debit card transaction? It really irks me (much more than it should)

It's more like 10p. Credit cards are usually a percentage.

The bank charges the retailer about 10p or a percentage as stated...

It's when the shop keeper charges US 50p that annoys me... I don't know if it's because they have to rent/buy the card readers from the bank or just to make a profit because the bank charges him when we pay wit the card (boo hoo, sob story about how running a business isn't easy with Tesco on every corner yadda yadda yadda )

[TheEnd]

juan king said:

What are the vents for? Seen on the front corners of most tractor units

I believe they are for air control and to reduce drag. They don't go anywhere, just force some of the air to make a tighter corner as they go round the edge of the cab. Any air that has been splatted by the front face would get forced out sideways, and this would leave a low pressure area on the corners.

It looks like this grabs that air, and directs it along the side to get rid of that pocket.

[juan king]

That makes sense, thanks

[GTIR]

Sea containers.
You know the ones on the back of trucks from China usually.

If they are lost overboard at sea and recovered do they reuse them after the goods are disposed off?

And related to that - if I found one on a beach could I claim it as salvage, lot what those people did on that UK beach?

[Hugo a Gogo]

they're not worth much, there's a surplus of them in europe (we import more than we export)

[Blib]

Would a cup of tea with the teabag removed cool quicker than a similar cup with the teabag left in?

Thank you.

[Hugo a Gogo]

teabag in the cup you say?

[AstonZagato]

With or without a teaspoon?

[Blib]

Look, if you're not going to take my question seriously, I'm going to flounce.

[Nimby]

Blib said:

Would a cup of tea with the teabag removed cool quicker than a similar cup with the teabag left in?

Thank you.

I would think so. A lot of the cooling would be from convection currents bringing the hottest tea to the top where it cools by contact with the air and evaporation (latent heat loss). With a teabag floating at the top that would be much reduced.

[scarble]

surely then it depends on the orientation of the tea bag and depth within the tea?
sometimes they sink to the bottom, sometimes they float, sometimes they sit vertically, sometimes they list a bit.
I wonder what the thermal conductivity of a sodden tea bag is vis-a-vis tea?
Surely one assumes it to be lessened and thus of an insulating nature?

[Blib]

I was thinking that the tea bag would retain heat in the mass of the tea leaves. Like a radiator does.

[scarble]

Radiators don't retain heat, they radiate it, hence the name
I don't think the mass of the leaves is greater than the mass of water it displaces, if anything the thermal capacity of water is greater, but it's also a better conductor (and a better convector, as it flows, being a fluid).
I would hypothesise that the chief thermal loss is due to convection currents in the air above the cup carrying heat away but convection currents in the tea would also need to carry heat from lower in the cup up to the tea/air boundary such that it can be transferred to the air and I hypothesise that the teabag would to some extent disrupt these currents and this I believe may slow the cooling.

[RenesisEvo]

TheEnd said:

juan king said:

What are the vents for? Seen on the front corners of most tractor units

I believe they are for air control and to reduce drag. They don't go anywhere, just force some of the air to make a tighter corner as they go round the edge of the cab. Any air that has been splatted by the front face would get forced out sideways, and this would leave a low pressure area on the corners.

It looks like this grabs that air, and directs it along the side to get rid of that pocket.

I once did a study using CFD (computational fluid dynamics) and I was surprised at just how ineffective those were at reducing drag. They may help guide the air round the corner, but with a big enough radius on the corner (which it has) they don't really assist that much. You just can't get away from the big, bluff face and many rotating wheels without changes in legislation and working practices. The cynic in me wonders if they are simply there to appease the people who buy trucks to make them think the manufacturer is trying to reduce drag.

[Blib]

scarble said:

Radiators don't retain heat, they radiate it, hence the name