Mike,
In such cases I apply a variable constant.
Happy POETS Day
Regards
Eric Dawson
> -----Original Message-----
> From: Mike Fenner [SMTP:[log in to unmask]]
> Sent: Friday, October 26, 2001 8:33 AM
> To: [log in to unmask]
> Subject: Re: [TN] Adjusting the alloy composition in the solderpot
>
> So using your formula that makes Bev about 150 years old percent then, or
> did I miss something.
>
> Happy Friday.
>
> Best regards
>
> Mike
>
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of Lou Hart
> Sent: Thursday, October 25, 2001 5:51 PM
> To: [log in to unmask]
> Subject: Re: [TN] Adjusting the alloy composition in the solderpot
>
>
> Eric, Steve, et al,
>
> I recommend going back to basic calculus and calculating the derivative of
> fraction tin with respect to weight (mass) of tin.
>
> Fraction tin = (Tin mass)/(Tin mass + Lead mass)
>
> You will get (assuming you only want a small change in fraction tin, in
> the
> range of, say, 0.03 or less)
>
> Tin add = (Mass of pot) X (change desired in Fraction Tin)/(Fraction Lead)
>
> On an unrelated matter, let me comment that a number of names like
> Shirley,
> Beverly, and Vivian were used by men until the first half of the past
> century. Over some time period, women largely took possession of them.
> Lou Hart
>
>
>
> -----Original Message-----
> From: Eric Dawson [SMTP:[log in to unmask]]
> Sent: Thursday, October 25, 2001 2:53 AM
> To: [log in to unmask]
> Subject: Re: [TN] Adjusting the alloy composition in the solderpot
>
> Hi All,
> The easiest way to think of this is not the use of a complicated formula,
> but the simple application of percentage.
>
> In the example below, the total weight of tin plus lead is 1500 pounds,
> 61.9% of which is tin. Hence there are 928.5 pounds of tin.
> Add 45 pounds of tin, the total weight is now 1545 pounds of which, 973.5
> pounds is tin. Work out the new percentage of the new total weight and you
> get 63%.
> Ahah, I hear you ask, how do you get to 45 pounds in the first place?
> Well,
> just plug a few numbers into the percentage calculations and see which
> direction it takes you.
> The main thing to remember is that you add the tin addition to the total
> weight as well as the tin content when working out the new percentage.
> Hope this helps
> Regards
> Eric Dawson
>
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