I’m currently not completely convinced that these “direct air capture” systems that remove carbon dioxide from the atmosphere are very practical. Technically they can certainly work, but the capital and operating costs are probably substantial, compared to the amount of CO2 you recover. However, if they do become widespread (as the linked article suggests), that will keep a lot of chemical engineers busy. And mechanical and electrical engineers too! And civil engineers during the construction phase.
There aren’t very many positive things to say about a pandemic, but perhaps one positive outcome has been the successful advancement of mRNA vaccine technology. Although some people have the impression that this was very rapidly developed over the past year or so, the mRNA idea dates back to the late 1980s. It’s actually been undergoing development for 20+ years, although obviously the target wasn’t always the coronavirus. As a chemical engineer, I’m interested in the scale-up and production aspects, since that’s what we do best.
As a vaccine production method, the mRNA platform is exciting because it is so fast. Traditional vaccine production methods required the growth of batches of cells to produce the vaccine components. This cell growth is done in big tanks, sort of like beer brewing, but is typically slow. It may take many days or weeks to get one batch done. Some vaccines are still produced in chicken eggs (influenza) or cells grown in small “roller bottles” (measles). All of these are slow and difficult to scale-up to produce billions of doses.
The mRNA production method is not cell-growth based, it just uses a biochemical synthesis method. Here, you just mix a bunch of ingredients, add some enzymes to assemble the mRNA molecules, then enclose them in some nanoparticles. These nanoparticles are a key part of the product, and they serve a couple of key roles: 1) they protect the mRNA from degradation, since RNA is fairly unstable especially once injected into your arm; and 2) they provide the mechanism for the mRNA to get into your muscle cells where your body uses it to produce the “antigen” (the piece of virus protein that your body learns to recognize and fight, if you’re ever infected with the virus in the future).
This biochemical synthesis method can be done in a few hours, versus the days or weeks for the traditional vaccine manufacturing methods. There are still some purification and packaging steps involved which take some more time, but the overall process is still very fast in comparison to the older ones. The mRNA platform is very adaptable too, so the vaccine can be quickly modified if necessary, as the virus mutates, just by changing the “manufacturing template” (DNA plasmid) that assembles the mRNA molecules.
The Sartorius company (a science materials & equipment supplier) has produced a short video giving some information about mRNA vaccines and production, which is pretty good and not too technical.
After writing a recent post about helium supply and demand, this news article came up about a new helium production facility in Canada. I wasn’t aware that it was under construction, but it’s nice to see some Canadian progress in securing supplies of this important resource. The photo shows some typical chemical engineering design elements like piperacks, process vessels, separators, compressors, etc. How to put together a process like this, in a safe, sustainable, and economical way, is one aspect of chemical engineering education.
Since the pandemic flared in North America, I’ve had quite a few discussions about UV disinfection with media, companies, hospital staff, and various other interested people. There are two major concerns I always try to emphasize:
- UV can be an effective disinfection tool IF and ONLY IF it’s used properly (distance, time, power) and at the correct wavelengths (e.g. UV in sunlight, not so good); and
- UV disinfection is not safe for the “amateur” user unless it’s been properly designed and engineered into a system that prevents people from exposing their eyes or skin.
Unfortunately, there are many products now out on the market, widely available to the public, that don’t meet concern #1, or #2, or even both! Concern #1 is not so bad for the public. If someone thinks they are disinfecting something but it actually is doing nothing, then it’s more a waste of time and money than a safety issue (as long as they don’t ignore other infection prevention suggestions). Concern #2 (safety) however, is a more serious issue. And now in the media (as in the link above), we start to see reports of people with eye damage due to these inappropriate (and potentially illegal) devices. This is sad, and has potentially long-term consequences for those individuals.
My recommendation: don’t mess around with UV disinfection unless you really know what you are doing. It’s fine in commercial, hospital, and other installations where it has been properly done. I don’t recommend it for home use in rooms or those hand-held devices. For those who contact me, I’m usually happy to provide quick initial impressions on UV devices and their practicality and safety.
Chemical 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 reading
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 (email@example.com).
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.
A nice example of mechanical engineering students using their skills to solve real-world problems. See the link below for more details.
Five mechanical engineering students created the Enhanced Mobility Wheelchair for their 2019 capstone design project, and now their work is being nationally recognized for improving accessibility and inclusivity in Canada.
Wheelchair users often face challenges when deciding which device to use to get around. Regular wheelchairs are easy to manoeuvre, but hand-cycle wheelchairs offer better speed efficiency. The Enhanced Mobility Wheelchair team has designed and prototyped an augmented wheelchair that provides users with the comfort and maneuverability of a traditional wheelchair while offering the speed of a hand-cycle wheelchair. The novel drive system provides greater ergonomic support and promotes good posture even when the operator is tired. Selectable gear ratios greatly improve motion efficiency on a variety of terrain, helping those confined to a wheelchair go further and faster than ever before.
The latest university ranking scheme is one from Times Higher Education (THE) and their University Impact Rankings for 2019. This new ranking is based on the 17 UN Sustainable Development Goals and how well each university contributes towards meeting those goals. According to a news summary, Waterloo does particularly well on 4 of the goals, namely Partnership for the Goals, Sustainable Cities and Communities, Climate Action, and Reduced Inequalities.
Overall, Canadian universities score well in these sustainability rankings, with McMaster #2, UBC tied for #3, University of Montreal tied for #7, York #26, and Toronto #31. McGill comes in somewhere in the 101-200 range. I haven’t spent any time looking at the details yet, so I’m not sure what contributes to some of these rankings.
A lot of the “top” US universities didn’t participate in these rankings, so it’s hard to make many comparisons. The top 3 ranked US colleges in these rankings were U of North Carolina at Chapel Hill at #24, Arizona State at #35, and U Maryland Baltimore County at #62. I’m aware of these places because they have strong STEM programs and research activities, but most Canadians probably aren’t aware of them. Perhaps next year more US colleges will participate.
In general, sustainable development is an important goal and increasingly a part of engineering education and practice. Engineers Canada, the body responsible for accreditation of engineering education in Canada (among other things), has a national guideline on sustainable development for professional engineers published in 2016. Various bits and pieces of this are already built into our curriculum for chemical engineers (and I assume in other disciplines), but there are further improvements we continue to work towards.
For further news details: https://uwaterloo.ca/news/news/university-waterloo-among-top-schools-world-social-and
See the link below for the full story, but nice to see my department (Chemical Engineering) ranked in the top 100 worldwide. The two others are Electrical Engineering (49th) and Civil Engineering (51 to 100 range). Mechanical Engineering ranked in the top 150.
Waterloo Engineering notched three top-100 results in the Quacquarelli Symonds (QS) worldwide university subject rankings released today for 2019.