Doug, Thanks for adding your important two cents. Could you show us an example with the necessary conversions numbers. Also there is the concept of equilivalents/mole where the number of equivalents is effectively the valence, i.e. 2 for Cu(+2). There are some cases where n is not an even intergal. All is all a dimensional analysis must yield a dimensionless number in the exp(E or H or F). Thanks Richard Haynes
-----Original Message----- From: Douglas Mckean <[email protected]> To: Richard Haynes <[email protected]> Cc: Parker, Thomas P (Paul) <[email protected]>; accelerated-stress-testing <[email protected]>; emc-pstc <[email protected]> List-Post: [email protected] Date: Tuesday, July 28, 1998 10:01 PM Subject: Re: AST Tutorial on the Use of Tempature to increase Acceleration Factor >Hope you guys don't mind my two cents but I hope you're >assuming something here which I don't see. The units for >the Gas Constant used in the Arrhenius' equation is > > R (gas constant) = J/mol*K or cal/mol*K > >That means Ea (activation energy) must be in units J/mol, or cal/mol. > >If the units of eV's are being used, then all the constants >must have their corresponding units changed also to eV's so that > > R = eV/mol*K and Ea = eV/mol > >To say that H is simply the units of calories is a little misleading. >It's units are cal/mol. Very different concept than simple cals. > >Regards, Doug > >Richard Haynes wrote: >> >> Paul, >> Thank you for your suggestion. I hope these comments will be useful. >> Richard Haynes >> >> Applications of the Arrhenius type equation include chemical and >> electrochemical reactions and many other systems such as bipolar and MOS >> infant mortality. Both temperature and voltage are accelerating factors(D. >> Cook, "Method of Determining Reliability Screens for Time Dependent >> Dielectric Breakdown ," Proceedings of the International Reliability Physics >> Symposium, IEEE, 1979, p. 1.). >> When using the Arrhenius type equation several variations of representations >> of the energy of activation are being used, such at E( energy of activation >> with eV units), H and F( heat and free energy of activation, both in cals or >> kcals-kilocals, 1,000 cals). Each means the same measure of energy, that is, >> the energy necessary to be supplied so the system can reach the final state. >> -----Original Message----- >> From: Parker, Thomas P (Paul) <[email protected]> >> To: 'Richard Haynes' <[email protected]> >> Date: Friday, July 24, 1998 8:54 AM >> Subject: RE: AST Tutorial on the Use of Tempature to increase Acceleration >> Factor >> >> Richard - Most people are used to seeing Ea for activation engery in >> electron volts, vs H in the Arrhenius equation. I would suggest explaining >> that. >> >> Many failure modes do not necessarily follow Arrhenius, especially >> workmanship defects and other mechanical defects. Can you be discuss the >> types of failure modes that this equation applies to as well as what it does >> not apply to. Actual experimental examples would be great. >> >> Paul >> >> > ---------- >> > From: Richard Haynes[SMTP:[email protected]] >> > Sent: Friday, July 24, 1998 3:02 AM >> > To: emc-pstc; accelerated-stress-testing >> > Subject: AST Tutorial on the Use of Tempature to increase >> > Acceleration Factor >> > >> > <<File: Temparrt.doc>> >> > Greeting Groups, >> > I hope this tutorial will clear up some aspects of using the temperature >> > to increase the acceleration Factory. >> > Please let me know if this was helpful so I can tell my boss. >> > Thanks and have a good day. >> > Richard Haynes >> > >> > PS The attached file is in Word 6.0 >> > >
