3D Printing in construction

Image from article

Students in various fields of engineering find 3D printing to be an extremely interesting innovation. In an article I use as a model text for explaining how something works, the focus is on how 3D printing could eventually be used in large-scale projects in the construction industry.

The article is How to print a building: the science behind 3D printing in construction, by Seyed Ghaffar, Assistant Professor in Civil Engineering and Environmental Materials, Brunel University London.

Link to the article: https://theconversation.com/how-to-print-a-building-the-science-behind-3d-printing-in-construction-98490

In addition to being an interesting topic for my students, the article has many language features that I guide them to incorporate into their own writing, especially when writing a process description.

The first sentence of the article gives an indication of the intended audience of the article:

• It's often claimed that 3D printing -- known in the trade as "additive manufacturing" -- will change the way we live.

I call students' attention to the use of the phrase in boldface -- obviously it is focusing on those who are not "in the trade." There are other indications in the article that it is written for a non-expert audience.

• The simple approach of layer-wise construction -- where building materials are layered on top of each other to create a facade -- has already been practised for a long time in the construction sector, for example in conventional brick layering techniques.

Here, a description of what "layer-wise construction is" and a specific example of where this has already been used in construction are further examples of audience focus.

• One component is printable feedstocks -- the materials which are actually "printed" to create the final product.

And here, the term "feedstocks" is explained.

To describe how 3D printing could be used as well as what some of the problems are, there is language to present comparisons:

• But it's one thing to build small, prototype homes in a park -- it's quite another to ...
• Yet in some ways, it's not as ...
• But there is still some way to go before ...
• ... can work faster -- but it also puts the feedstock at risk of ...
• But before that can happen, ...

There is also language of cause and effect:

• so that the layers can be deposited rapidly.
• to achieve a robust structure which can take load.
• must be just right, so that ...
• need to be formulated and developed, so that this technology ...
• printer, which must have a power pump to suit ...
• The speed and the size of the printer is key to ...
• Decreasing the setting time of the feedstock means that the printer ...
• a constant rate, so that the layers can ...

The article has many examples of passive voice, which is contrasted with the use of the active voice; for example:

• To create materials for 3D printed constructions, scientists must carefully control (active voice) the setting time of the paste, the stability of the first few layers and the bonding between the layers. The behaviour of the materials must be thoroughly investigated (passive voice) under a range of conditions, to achieve a robust structure which can take load.

Other examples of the passive voice:

• It's often claimed that 3D printing -- known in the trade as "additive manufacturing"
• ... layer-wise construction -- where building materials are layered on top of each other to create a facade -- has already been practised for a long time
• ... to automate and improve processes that have already been proven manually. 
• ... different components of additive manufacturing, each of which must be developed and refined before the process can be successfully used ...
• ... the materials which are actually "printed"
• Printable feedstocks are typically made from a combination of bulk materials
• ... so that the layers can be deposited rapidly.
• ... and don't stay wet for too long once they have been deposited to form a structure. Different grades of feedstock need to be formulated and developed, so that this technology can be used to build a range of different structural elements, ...
• The pressure and flow rate of the printer must be trialled with different types of feedstocks.
• Only then can the potential of 3D printing be harnessed to build faster, and more sustainably, than ever before.

There is another useful contrast of vocabulary my students often have trouble with: the difference between fewer and less for count and non-count nouns in English:

• 3D printing can produce up to 30% less material waste, use less energy and fewer resources, enable in-situ production (which in turn cuts transports costs), grant greater architectural freedom and generate fewer CO2 emissions over the entire lifecycle of the product.

This sentence also has a variety of verb-noun collocations that are useful in technical writing:

• produce waste
• use energy
• use resources
• enable production
• cuts costs
• grant freedom
• generate emissions

Other noun-verb collocations:

• announce plans
• create a facade
• automate processes
• deliver on potential
• set concrete
• maintain shape

As a quick wrap-up to the lesson, I had students highlight verbs they thought could be used in different types of technical writing. This helps them to realize that they already know "technical vocabulary" because these verbs are quite common. Here's the list they came up with:

• build
• use
• layer
• create
• practise
• combine
• automate
• improve
• produce
• generate
• develop
• refine
• mix
• set
• maintain
• deposit
• investigate
• achieve
• formulate
• measure
• speed up
• slow down
• optimise
• fuse
• take load
• provide
• revolutionise
• harness

Since many of these verbs are used more than once, students can notice the different collocations used for them -- verb-noun, verb-preposition, or adverb-verb.

The article includes a link to a text on the Brunel University website for which Prof. Ghaffar is also an author: Additive Manufacturing Technology in Construction (AMTC). This can serve an example of how some of the same informaiton is written for an expert audience.

For example, information written first for the expert article, contrasted with the information from this (non-expert) article:

1. Additive manufacturing (AM) is a procedure that forms layers to create a three-dimensional solid object from a digital model.
2. The simple approach of layer-wise construction -- where building materials are layered on top of each other to create a facade, ...

Impact of concrete

My students learn impact analysis so they can understand the kind of impact their future innovations might have on the world someday as engineers -- including those impacts that were not intended. I have looked at this in a number of posts over the years. An article I used recently is about the impact of concrete: specifically, how concrete contributes to global warming.

The article is Feeling the Heat? Blame Concrete and the subtitle is particularly eye-catching: Concrete has transformed civilization -- but it's making our cities, and our world, hotter. So it is clear that the article looks at both the pros and cons of concrete.

Link to the article: https://time.com/5655074/concrete-urban-heat/?utm_source=newsletter&utm_medium=email&utm_campaign=the-brief-pm&utm_content=20190820&xid=newsletter-brief

A non-narrated video (56 seconds) on the same site as this article starts: "July 2019 was the hottest July and the hottest month on record globally since temperature records began."

As an argumentative, or opinion, essay -- looking at the pros and cons, it is very well structured in the English style: 

• Introduction: topic and specific focus of topic
• Advantages of concrete, with examples (2 paragraphs)
• Disadvantages of concrete, with examples (9 paragraphs)
• Conclusion: indication of future concerns

This, then, serves as a good model text for English essay organization. Since the main focus of the disadvantages is on how concrete contributes to global warming, there is also information about how this occurs. This includes useful phrases and collocations relating to heat:

• potency of heat waves
• soaks up and retains the sun's heat
• temperatures rise
• magnify that effect
• urban heat islands
• the heat released by vehicle engines
• boost the temperature
• soaring (city) temperatures
• a rapidly warming world

A useful feature for argumentative essays is the use of comparisons that the audience will understand (many of these focus on an American audience):

• If you've ever walked barefoot across a sunbaked parking lot, you know firsthand how concrete soaks up and retains the sun's heat.
• Heat already kills more Americans than hurricanes, lightning, tornadoes, floods, and earthquakes combined.
• That's the equivalent of adding nine New York Cities to the planet every year.
• ... making it the third-largest source of global-warming, behind only coal-fueled power plants and combustion-engine vehicles.
• ... enough to blanket the entire state of California.
• There is so much money to be made off of sand that in some countries, organized criminal gangs have moved into the business.
• We tend to think of concrete as permanent as the stone it mimics. It's not.
• America's dams are in similarly dismal shape.

Since the argumentation consists of information about the impact of concrete, there are many examples of cause and effect (with useful phrases in bold):

• When temperatures rise, the countless miles of concrete streets, sidewalks, walls and roofs in cities magnify that effect, creating a phenomenon known as urban heat islands. When combined with the heat released by vehicle engines, paved areas can boost the temperature in cities by as much as 22°F, ...
• The urban heat island effect is ever more worrisome because more and more people are moving into cities.
• Concrete is essentially just sand and gravel glued together with cement. To feed the construction industry's needs, tens of billions of tons of sand are dug out of the earth each year, enough to blanket the entire state of California. Much of it is dredged from river beds, lake bottoms, and beaches. The process often slaughters river-dwelling fish and birds, damages coral reefs, undermines bridges and causes riverbanks to collapse.
• There is so much money to be made off of sand that in some countries, organized criminal gangs have moved into the business.
• Heat, cold, chemicals, salt, and moisture all attack that seemingly solid artificial stone, working to weaken and shatter it from within. If it's not monitored and maintained, most concrete slowly disintegrates.

The final sentence is: "We can't stop using concrete completely; it's far too useful as a building material. But in a rapidly warming world, we need to start thinking about its true costs."

It would be interesting to see what engineering students would propose as a solution to this -- and it might depend on which field of engineering they are studying.

The author of the article is Vince Beiser, who is mentioned as the author of the book, The World in a Grain: The Story of Sand and How It Transformed Civilization. I haven't read this book, but it certainly sounds as if it is all about impact. Perhaps there are students or teachers who would be interested in reading it!

How to launch a rocket from a plane

Virgin Orbit / Greg Robinson

In January, the firm Virgin Orbit successfully launched a rocket from a plane. The LauncherOne rocket carried 10 of NASA's satellites and was brought 11 kilometers (6.8 miles) into the atmosphere by a modified Boeing 747. The article I used is called "Virgin Orbit launched a rocket from a plane -- here's how" by Simon Lindsay, a Researcher in the School of Physics and Astronomy at the University of Leicester. It describes how this was done -- clearly and concisely in the first 3 paragraphs -- and explains why this was an important development for space travel.

Link to the article: https://theconversation.com/virgin-orbit-launched-a-rocket-from-a-plane-heres-how-154207

The explanation of how this was accomplished is an excellent example of a process description, which my students have to learn how to do in both writing and speaking. In addition, there are examples of making this explanation clear to a non-technical audience - and this is something I find useful to bring to students' attention so that they use it in their own explanations. For example:

• Earlier this month, ten cubesats -- small, cheap satellites weighing about a kilogram each -- were sent into orbit around Earth.
• With almost 1,500 of these small satellites launched so far, adding another ten might seem trivial. But this was no ordinary launch.
• But how does launching a rocket from a plane actually work?
• Usually, a rocket launched from a launch site on the ground will have two or three stages, which allow the rocket to shed weight as it uses up fuel.
• ... the payload -- the part we want to get into space -- ...
• ... but most of the fuel requirement to achieve orbit is not in gaining height, but getting it moving with enough speed so that it falls into orbit.
• For small satellites, cubesats, micro-satellites and nano-satellites -- all of which are being rapidly adopted by the space industry -- air launches could represent ...
• The idea of air launching has been around for some time.
• ... which may be able to place smaller satellites -- 50 kg or so -- into much more distant orbits ...

In describing both the process and the advantages of this process, there is a variety of adverbs used, which combine to form useful collocations. My students either do not use many adverbs or they confuse their use with adjectives. But in the article, adverbs are used to be more precise, which is also something students should use in their own writing. Some examples:

• actually work
• typically places (the noun)
• repeatedly delayed
• can simply be flown
• can easily be accommodated
• a relatively small (noun)
• being rapidly adopted by
• an improvement in versatility and, crucially, cost
• aims to fully combine (noun and noun)
• an increasingly competitive market
• relatively low cost

The next feature I highlight for my students is the use of "referents" -- words or phrases that refer to something already mentioned. In their writing, my students often keep repeating the same word, which produces an inelegant, repetitive text. I ask students to identify what a specific term refers to -- either in the same sentence or in a previous sentence -- so they can see how this can be done. In this article, there are many uses of "its," which helps students see how this word is used and (hopefully) how not to confuse it with "it's" (of which there is only 1 in the text). Some examples:

What does (italicized term) refer to in the following sentences:

• The plane carried them to a height of 11km ...
• This was the first successful launch of Virgin Orbit's LauncherOne rocket, marking the start of its commercial ventures. The company hopes to ...
• A third stage operatres on the same principle and ...
• Air-launching takes advantage of this by attaching a rocket to an aircraft and releasing it ...
• Stratolaunch, the developers of the enormous carrier aircraft of the same name able to carry a rocket weighing 250 tons, abandoned its heavy-lift launch vehicle program in 2019.
• While the flight speed of an aircraft can make a small contribution to this requirement, the fuel saving from air launch is not as large as it might first appear.
• The Pegasus launch service is still operational, and has completed 30 successful flights, but its launches are expensive ...

While I like to focus on the useful language features of this article, my students are interested in the topic and the possibilities for the future.

Engineering humor

My material for classes with engineering students doesn't usually involve intentional humor, but after coming across various "engineer jokes" on the internet, I shared some of them with my students. It was not only a nice break during the lesson, but it also started discussions about aspects of engineering and/or cultural aspects of humor.

One of the first engineer jokes I remember hearing was:

• An optimist says the glass is half full, a pessimist says the glass is half empty, and an engineer says the glass is twice as big as it has to be.

Do cultures other than English-language ones have the concept of the half-full (optimist) and half-empty (pessimist) glass? What are the different concepts that different cultures joke about - or would not joke about?

To bring some of these questions into lessons, I searched the internet for jokes specifically about engineers or engineering, and it turns out there are a lot of them! The first article I focused on was "25 Best Engineering Jokes That Will Make Your Day Better," written by Christopher McFadden on the website interestingengineering.com (see my Relevant Links):

https://interestingengineering.com/25-best-engineering-jokes-make-your-day-better

Which jokes could be translated into students' language(s) and which are dependent on English language or English-culture ideas? For example, jokes that depend on puns for their humor cannot be directly translated into another language. One of the engineering jokes in the article puns with the words four and for and with what and watt:

• Customer: Do you have any two-watt, 4-volt bulbs?
• Sales Rep: For what?
• Customer: No, two.
• Sales Rep: Two what?
• Customer: Yes.
• Sales Rep: No.

Some jokes require certain technical knowledge to understand why it's intended to be funny. One joke in particular, referred to as "the most brilliant joke ever written," I didn't understand at all until my students explained it to me:

• One day, Einstein, Newton, and Pascal meet up and decide to play a game of "hide and seek." Einstein volunteered to go first. As he counted, Pascal ran away scrambling to find a great hiding place. Giddily, he squeezed into a crawl space sure that he would win this time, as this was his best hiding spot to date and Newton surely wouldn't find an equal. Newton, on the other hand, stood right in front of Einstein, pulled out a piece of chalk, and drew a box on the ground of roughly 1x1 meters. Once this was completed, he sat down neatly inside the box and waited for Einstein to finish counting. When Einstein opened his eyes, he of course saw Newton and with a bit of disappointment said, "I found you, Newton, you lose." But Newton repliced, "On the contrary, you are looking at one Newton over a square meter. Pascal loses!"

If you don't understand the reason this is funny, I have given the reason at the end of this post.

There are links to other websites with engineering jokes, and many of them are the same as in this article. What is interesting about the language is that there are certain "templates" to jokes in English that can be seen throughout the choices. Some examples from the jokes in this article:

• An X, a Y and a Z (verb) ...
• A priest, a doctor and an engineer were waiting ...
• An engineer, a statistician and a physicist are out hunting ...
• Or, a variant: Three Xs were (verb)
• Three engineering students were gathered together discussing ...
• Why did the X (verb)?
• Why did the engineering students leave class early?
• Why does the Polish airline have ...?
• How many Xs does it take to change a lightbulb?
• How many nuclear engineers does it take to change a lightbulb?
• What's the difference between an X and a Y?
• What's the difference between an introverted and an extroverted engineer?

One of the jokes is a cartoon from the website XKCD, which I referred to in my post of June 7, 2013, titled Cartoons for ESL. The website is still current - and funny. Using humor in lessons can be an interesting change, and it breaks the stereotype of engineers as being humorless!

* Because 1 Pascal = 1 Newton/m2