Here’s a nice summary article about aerosol viral transmission, by a mechanical engineering professor. The physics of aerosols is a foundational concept in air pollution control.
Aerosols are the tiny particles of liquid and material that float around in our environment. When they come from an infected person, they may be a significant source of coronavirus transmission.
Sometimes I see people getting concerned about future prospects for chemical engineering careers, usually because of some downturn in the oil and gas markets. I guess we should never stop emphasizing that chemical engineering is much more than oil, gas, and petrochemicals! There is also food, pharmaceuticals, alternative energy, environment, safety, consumer products, plastics, minerals, metals, paper & fibers, etc….
Actually, the next 30 years is probably going to be a very exciting and technically challenging time to be a chemical engineer. The world needs people with the innovation skills to handle new materials and energy processes more than ever. Why is that? Here are a few quick thoughts…
Continue readingAn interesting story below about an engineer using his observations in water treatment to innovate and improve work-flow for lots of other companies. A chemical engineering education can lead in lots of different directions!
In 2014, freshly graduated UC Berkeley alum Ryan Chan was working as a chemical engineer at a water purification plant, when he realized that the company was constantly facing equipment downtime. The workers used a maintenance program that helped them track all the breakdowns, but there was a big problem with the software they were using that was slowing them down.
“Everything was desktop based, but the maintenance team, the people that were using it, never sat at a desk,” Chan says.
So Chan realized there had to be a smarter, mobile-first solution for all the blue collar workers across facilities. He wound up teaching himself how to code at night and on weekends, and developed the app while he worked as a chemical engineer, and later as an iOS developer.
In 2016, Chan launched UpKeep, an app developed for facility managers and maintenance workers that allows them to flag things that need repairs and run equipment audits across facilities.
Soap and water is a preferred choice for hand hygiene and reducing microbial and viral contamination. However this isn’t always convenient or available when out walking or shopping for necessities, so the next best thing is a hand sanitizer formulation. The nice commercial ones are in short supply, but it is relatively easy to blend your own if you can access the ingredients. Blending chemicals safely is another chemical engineering specialty. Here’s a recipe for small volumes for home use, with some discussion on the physical chemistry basis for the various components.
Continue readingChemical Engineering: the art and science of creating and operating industrial scale systems for transforming raw materials into useful products.
When “chemical engineering” is mentioned, many people think of chemical plants, refineries, and such. That’s one part of it, but it also encompasses many other things, including pharmaceuticals and vaccine manufacture. These days, everyone is talking about and hoping for a vaccine for Covid-19. What does this mean for some chemical engineers and what they need to do?
Continue readingThe last two weeks of our lectures for the Winter term (last two weeks of March) were all done “online”, since the on-campus activities were shut down. This was an interesting experience, especially since we only had a week to prepare. It took quite a few hours of effort to figure out the online technology and work out different ideas and approaches before starting.
For my Air Pollution Control course, I used Webex to deliver the last two weeks of lectures live, sort of like some Webinars I’ve done in the past. These lectures were also recorded so that students who couldn’t attend “live” could look at them later. I liked the live aspect, so that students could submit questions via the chat function as we went along. I think that the ability to ask and answer questions is important, and you lose something when it can’t be spontaneous.
Luckily for me, the last two weeks of material in my course was relatively easy to adapt for online delivery. It was largely descriptive, not so much mathematical or technical. Some things that I would have normally done on the board in a classroom I had to adapt into a powerpoint deck, but it wasn’t too bad.
Delivering a whole course online is another matter, which my colleagues are scrambling to do for the term starting in May. Doing it really well takes substantial development work and a pedagogical re-think of virtually everything about the course. From what I’ve read, properly developing a truly excellent online course can take many months of preparation, audio/video recording, and editing.
Unfortunately we haven’t had a lot of time to do this, but our instructors seem to be seriously working on it as best as they can. I don’t have any courses to teach in the May-August term, but I’m keeping a close eye on how it’s done in case we are still teaching online in September when I teach another course. The university has developed a website where we can find some suggestions and other resources for online teaching. I hope we can have classroom teaching again in September, but there are some doubts and I guess we have to be prepared for anything at this stage.
Recent pandemic developments have strained the supply of N95 filtering facepiece respirators (FFRs), which protect users from particles and aerosols in the air that they breathe. Technically, they must filter out at least 95% of 0.3 micrometre particles.
Normally these are meant to be single-use devices, and are removed and disposed of in a secure way to prevent infection transmission. However, with supply shortages people are considering or resorting to re-using these FFRs, possibly with some sort of chemical or physical disinfection process. Disinfection processes are never 100% effective, so this is not a great option, but I guess it’s better than having no protection.
One disinfection method that I’m very familiar with is UV-C disinfection, having done research in the area of photochemical processes for several decades. There is published literature available demonstrating reasonable disinfection success for UV when applied to N95 FFRs, so this may be an approach to consider if necessary.
I’m working on an overview of this literature (draft version now available at this link), but I’m happy to consult (pro bono) with health care institutions that are considering UV applications to deal with their situations (wanderson@uwaterloo.ca).
With the recent development of a viral pandemic, people are being reminded about the importance of handwashing for infection prevention. Coincidentally, in 2019 my colleague Prof. Marc Aucoin and I supervised a research study on handwashing for the CSA Group, a product standards organization. Specifically, our study aimed to determine if the faucet water flow rate had a significant effect on the ability of handwashing to remove bacteria from the skin.
You can access and read the full report on their website. The bottom line is that no, the water flow rate from the faucet didn’t have a significant effect over the range we tested, from 0.5 to 2.2 gallons per minute (about 2 to 8 litres per minute). Under all of those flow rates, on average about 99.3% of E. coli bacteria would be removed from the hands, which is good to know.
To do this study, we had to control all the other variables as much as possible, including the water temperature, and the amount and type of hand soap used by each person. The other big factor is the way that the hands were washed, including the length of time. For this study, we used a certain protocol from Public Health, and everyone involved in the study learned how to properly wash their hands. This was a good learning opportunity for people, including me, and so I reproduce the protocol that we used below. It’s a useful skill to know how to thoroughly wash your hands these days.
My blog statistics show that an old post from 2013 on Engineering Failure Rates continues to be a popular one to visit. There is an updated one available too, from 2018. As those blogs note, the data is from Ontario’s CUDO website and their definition of “success” is rather broad. If you start in Engineering, and graduate within 7 years from the SAME university with ANY degree, that counts as success for degree completion. So, if you start in Engineering then switch and graduate with a degree in Music, that’s success. However, if you start in Engineering, then leave before graduation to complete a Veterinary degree at Guelph, that’s not a successful degree completion for their statistics. So if you look at those statistics, you need to be aware of what they actually mean (or don’t mean)!
Those statistics always bothered me, so I came up with an alternative measure of Engineering graduation rates, using the same CUDO data source. My hypothesis is that if we use the Engineering first year registration data for a certain year, and then compare that with the Engineering “degrees conferred” data four years later, then that will give us a rough estimate of “success”, specifically within Engineering programs as a whole.
So that’s what I did with downloads from the CUDO website, with the admission data from 2006 to 2012, and the degrees conferred data from 2010 to 2017. (I used a 5 year comparison for Waterloo, since our program takes 5 years to complete when you include the co-op work experience. All other universities can be completed in 4 years, so I used that comparison for the rest.) Based on this approach, we can summarize the results in the graph below, showing average degree completion rates. The “error bars” show plus and minus one standard deviation of the average “success rates” for each university (a measure of how variable the results are).
I call the graph “apparent success rates” because it still doesn’t use individual student data; it’s based on bulk numbers that can hide a lot of variables. Indeed, as we gaze at the graph we see some obviously puzzling results. The Engineering programs at Windsor and Lakehead are highly successful at graduating more engineering students then they admit!
Clearly there are some problems with this data analysis. For one, it doesn’t take into account the fact that some students at other universities can do an optional co-op or internship that will delay their graduation by a year. Secondly, it is based on first year registration data for each engineering program. This means that the students who transfer into Engineering from other programs within the University, or from other universities, are not counted. Likely this explains the ones where the graduation/success rates are over 100%, and may be a factor for those who have rates approaching 100%.
I have no deep insights into the other universities, but for Waterloo I know that in my experience we have extremely few transfers from other Universities, and very few from other programs at Waterloo. Therefore the average success/graduation rate at Waterloo of around 78% is likely a reasonable ballpark estimate for the fraction of new admits that graduate in 5 years.
This all just illustrates once again that defining “success” is complicated, and getting meaningful data to measure “success” is even harder. We just have to make do with what we can get, and recognize the limitations of the data.
For those applying to university for Fall 2020 admission, there is some homework you should have done, or at least started by now. Arguably, this is probably the most important homework that you have, even if no one has explicitly assigned it or told you to do it. Properly done, this homework will make success in university more likely. So what is this homework?
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A Professor in Waterloo Engineering 