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神经网络昆斯林的新闻组分类2006

From: [e-mail] (Bob Myers)
Date: Sat, 24 Apr 1993 05:24:20 GMT
Subject: Re: WD-40 as moisture repellant (was Lead Acid batteries & Concrete?)
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Organization: Hewlett-Packard, Fort Collins, CO, USA
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> >Please explain how cement is able to maintain a lower average temperature
> >than dirt.  Sheesh.......
> 
I hope David isn't going to be too upset with me for sticking my nose
in here again, but here goes......:-)

It isn't the average temperature that is the key factor here, but rather
which is better at transferring the heat out of the (presumably warmer
than ground temperature) battery.  Call it a question of thermal
conductivity, or of insulating ability, or "thermal mass" - whatever you
like.  Question - why does a concrete floor feel cooler than the 
surrounding dirt when you place your hand on it?


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
[e-mail]    Fort Collins, Colorado   |sentient life-form on this planet.