June 29th, 2020

Here’s a COVID-19 statistic – interpret it as you will…

A 23 June 2020 United Press International (UPI) headline in Health News (proclaims: “Less than half a population needs COVID-19 infection for herd immunity, study says.”

The report goes on to state: “The modeling study found that herd immunity potentially could be achieved with about 43 percent of the population being immune, as opposed to the 60 percent estimate derived from previous models.” This is based on modelling…


May 19th, 2020

Does the SARS-CoV-2 virus persist in Water-Miscible Metalworking Fluids?

Over the past two months, I have received quite a number of emails and phone calls asking if water-miscible metalworking fluids (MWFs) were likely to be a source of SARS-CoV-2 virus exposure for machinists and others working in machine shops.

My short answer is that nobody really knows. I know that this answer is not particularly reassuring, but the test methods needed to test MWFs and MWF mists for SARS-CoV-2 in…


April 14th, 2020

Why do I sometimes detect heavy microbial contamination but no evidence that it is causing problems to my fuel system?

Explanations that I’ve provided in the last three articles provide some of the answers to this question. In this post I’ll address another issue – microbial activity. The various microbiological test methods I’ve described in this blog series have provide information about either whether microbes are present or what sorts of microbes are present. General culture…


March 11th, 2020

Refresher from Parts 1 and 2: What do Microbiology Test Results Mean?

In my January and February Fuel & Fuel System Microbiology articles, I addressed two reasons why microbiology data do not always agree with other indicators of fuel or fuel system biodeterioration. Part 33 covered dilution effects. Although direct degradation of fuels can easily be demonstrated in 1 L jars with fuel over water, when a tank has more than 1 m3 (264 gal) of fuel over traces of water, the impact that…


February 18th, 2020

Refresher from Part 1: What do Microbiology Test Results Mean?

In January’s Fuel & Fuel System Microbiology article I led with this question and commented that it is actually a double question. In one sense, it is asking: “Do my microbiology test results tell me conclusively whether microbes are damaging my fuel or fuel system?” In another sense, the question means: “Why don’t the results from different fuel microbiology test kits always agree?” I am then asked why often,…



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