[RFI] Dr. Henning Leidecker's bio

[Jim P]

Dr. Henning Leidecker; much more than just a lamp expert
according to his bio - he has done work in a wide range of
fields including "tin whisker growth" and nanotubes and is
currently listed as "Chief Parts Engineer NASA Goddard
Space Flight Center" according to info here:

  http://klabs.org/mapld05/tutorials/reliability/leaders/leidecker_bio.htm

I only wanted to point out his background as I see many 'references'
in some circles/web postings about his being a lamp expert (at one
point in time he may well have done research in this area!) but he
seems to have been involved in a great many related fields involving
materials and technology at NASA's Goddard Space Flight Center.

Jim P // WB5WPA //



----- Original Message ----- 
From: "Stu Benner" <w3stu at myactv.net>
To: "'Donald Chester'" <k4kyv at hotmail.com>; <rfi at contesting.com>
Sent: Tuesday, November 21, 2006 7:16 PM
Subject: Re: [RFI] Haolgens AND . . .


> The reduction in life of an incandescent lamp when operated on DC versus
AC
> is attributable electromigration, a phenomenon in lamps commonly called
"DC
> notching." With DC applied, the tungsten molecules migrate within the
> filament and the filament takes on a "notched" appearance. The increased
> local resistance at the notch points along with the reduced physical
> strength result in decreased life. If AC is applied to the filament, this
> condition is avoided. A lamp operating on DC may have 20% to 50% of the
same
> lamp operated on AC.
>
> Much research was done on this at NASA-Goddard by their lamp expert Dr.
> Henning Leidecker. One of the life-limiting factors on the earlier GOES
> spacecraft (and others) was the life of the black bias (incandescent) lamp
> in the satellite sensors.
>
> Stu Benner
> W3STU
> www.emconsulting.com
>