Coming back to equation , we can deepen our understanding
of the meaning of the surviving concentration, Nt, of microorganisms.
Let t = 24 minutes, D = 6 minutes and No = 100,000 microorganisms / sample unit. According to eq.  the following number Nt of surviving organisms is obtained:
Log Nt = 5 - 24 / 6
= 5 - 4
Whose means that after 24 minutes treatment, the product is not sterilized because each sample unit [can, jar, etc.] is still contaminated by the Nt = 10 surviving organisms. During storage, the surviving organisms could grow and spoil the product. If spoiling organisms belong to a pathogenic group, the product may become toxic too.
For any sterilization process a suitable selection of Nt value must be done.
Let Nt = 1 survivor /10,000 units, . Nt = 10 -4 , and No = 10 5 , D = 3 for instance, and the time t required to achieve the chosen Nt level will be, from eq. :
t = 3 * [ 5 - (- 4) ] = 27
So, after a treatment time F T = 27 minutes at the lethal temperature T the initial contamination of No = 100,000 microorganisms / unit will be reduced to the expected level of one survivor per 10,000 treated units.
The survival level of 1/10,000 = 10 -4 organisms/sample unit could be regarded as a low enough survival probability and thus a satisfactory degree of final sterility.
I have a D8 flooded lead acid battery 1400CCA and 255Ah capacity. it is 6 years old on a boat with a 3 stage 12 amp charger which is on all the time when the boat is not in use.
battery is now very low in specific Gravity 1175 less than 40% capacity. it’s voltage 3 days after a full charge is . this is far too high and we suspected sulfation to possibly be the cause of the higher voltage.(we read this somewhere)
we then overcharged it at 16 volts and it only drew 3 amps . After about 17 hours the SG had gone up to above 1200 about a 50% charge. a remarkable improvement.
my question to you all is why is the battery voltage still high on open circuit and why is there only 3 amps of charge at 16volts. should we continue to overcharge it ?