Sunday, August 27, 2017

The traveling engineer

What would students consider to be the world's top engineering destinations? This could be an interesting question to ask at the beginning of the academic winter semester, when we often ask colleagues and students what they did over the summer holidays. Where would students choose to travel to see engineering wonders if they could go anywhere - and why the particular choice? Would it depend on which area of engineering they are specializing in? Where have they already been? After the students brainstorm answers, which destinations would they choose as the top five?

This is the theme of the article, Top 5 Engineering Destinations to See Before You Die, on the website Interesting Engineering:

Link: http://interestingengineering.com/top-engineering-destinations-to-see-before-you-die

As the introduction to the article states, "Whether they're world wonders or feats of modern engineering, all of these places possess certain awe-inspiring qualities sure to make your trip worth it."

These are the five destinations chosen in the article (all images are from the Interesting Engineering article):


 The Palm Islands, UAE
These islands are described as an "incredible feat of engineering," but they also have negative effects on the environment. "The area surrounding the islands has seen increased coastal erosion and odd wave patterns. Sediment from the construction ultimately suffocated and injured many of the marine life around the area and reduced the sunlight allowed through the water." Students can research what effect this has had on the environment, compared with the benefits of residential development. In addition, the article mentions that since these islands are near Dubai, engineers should also see Burj Kalifa (but without giving specific information).


Taj Mahal, India
I thought it was curious that the Taj Mahal was on this list, since I think of it as more of an architectural wonder and a highlight of Muslim art; but perhaps the engineering focus is on how it was constructed. "Construction of the giant stone structure required earthen ramps over a mile long leading up to the tomb in order to lift the large stones into place." This information could be compared to other structures that were constructed before the use of modern machinery.


The Great Wall of China, China
This would probably be on many students' list. In the article, it is referred to as "one of the most prolific engineering feats of all time." Students could research how it was built, noticing that it was constructed in different sections over a period of about 1000 years. So there were many different types of construction methods used.


The Panama Canal, Panama
This canal has quite a dramatic history. "At the time and even up to modern standards, the canal was one of the most difficult engineering projects ever undertaken." Students can research what, specifically, these difficulties were - and how they were overcome. The article claims that "One of the most surprising facts about this engineering marvel is just how long it takes to traverse it." Looking at a map of Panama, students could speculate how long it takes a ship to travel from the Atlantic to the Pacific Ocean (6-8 hours). What other "surprising facts" would they find in their research?


The Hoover Dam, USA
Students might not be as aware of this construction as they are of the other destinations on this list. As the article claimes, "While not presently anything to marvel over, the history surrounding the construction and documentation of the engineering places it at great importance to the history of engineering." This is rather tantalizing! Since there is no further explanation, students can find out themselves what makes this dam so important. This is also another example of an engineering feat that has had an impact on engineering.

The description of each destination is rather short, but focuses on the reason it is on the list. Students could write short descriptions in similar style for other destinations they might have chosen. Special focus could be put on the top engineering destinations in students' own countries. And, of course, if students (or teachers) have visited any of these destinations, their further impressions could be added to the discussion.

Saturday, August 19, 2017

Two-bladed wind turbines - continued

Photo by Clark (on flickr)
In my last post (Two-bladed offshore turbines, 12 August) I wrote about an article that claimed two-bladed offshore turbines were more efficient and more economical than three-bladed turbines. I looked for further information, and found an article from the MIT Technology Review website that had been written earlier - in June 2014. It also presents support for the advantages of two-bladed turbines, particulary those offshore.

The article is Two-Bladed Wind Turbines Make a Comeback.

Link: https://www.technologyreview.com/s/528581/two-bladed-wind-turbines-make-a-comeback/

Interestingly, despite the title, the article does not refer to two-bladed turbines having been used before, so it doesn't really focus on a "comeback." It focuses instead on the two-bladed model as being a recent "alternative." As a cross reference to the two-bladed turbine as being an earlier model, see the article by Martin Jakubowski in my last post.

What makes this Technology Review article interesting for me is that it has much of the same support as the first article, as well as many of the same language features. Students could read the articles, then find the advantages that are mentioned in both. They can also compare the way the advantages are described in a cause-and-effect (or "impact") style. For example:

From Jakubowski's article:
  • "...two-bladed rotors are better suited for wind turbines because of their flexible configuration -- namely, their attachement to the shaft by a flexible hinge. This allows the rotor to have a second degree of freedom. ... This flexible hinge reduces the impact of cyclic loading (fluctuating stresses and strains from the wind), and strongly reduces wear and tear -- fatigue -- on the components, thus extending the lifetime of the turbine."

From the Technology Review article:
  • "Two-bladed turbines cost less because they use fewer materials. The removal of one blade makes the rotor lighter, which in turn makes it possible to place the rotor on the downwind side of the tower. ... Light, flexible rotors translate into further materials savings in the turbine's gearbox, tower and foundation."

The advantages of the two-bladed wind turbine mentioned in both articles are:
  • reduced weight of rotor
  • lower material costs
  • lower operations and maintenance costs
  • easier to install
  • costs less to build

The articles mention a total of five disadvantages, and the one disadvantage they have in common is the louder noise:
  • "slightly higher tipspeed noise"
  • It's louder, for one thing, in part because the blades spin faster"
but both articles mention that this disadvantage is not important for offshore turbines:
  • "The only relevant disadvantages of the two-blade design ... are unimportant offshore."
  • "... although this isn't a problem offshore."
The language features I highlighted in my last post are also found in this article. By comparing the two articles, a number of the same features and phrases can be found in both.

Phrases for argumentation:
  • By some estimates,
  • More importantly,
  • In fact,
  • According to,
  • For that reason,
Collocations of technical advantages:
  • grow faster
  • costs can be brought down
  • greatly improve the economics
  • cost twice as much as
  • generate as much power as
  • costing twice as much as
  • less than those of
  • etc.

The linking and transition terms are also useful for students to highlight, since there are many in common in both articles, or terms that serve the same function. Just a few examples from the Technology Review article:
  • same as
  • as much as
  • but
  • which in turn
  • in part because
  • because of
  • however
  • for that reason
  • rather than

There are also words of comparison, superlatives, as well as adverbs.

I think that each article, or both articles compared, are good sources of information about two-bladed turbines as well as useful examples of argumentation and support, with relevant language features. It would be interesting for students to find further articles and sources of information about this turbine design for other comparisons.

Saturday, August 12, 2017

Two-bladed offshore turbines

Photo from Seawind Ocean Technology
Wind turbines have become very common across landscapes all over the world, and they all have three blades. I have never thought about why there are three blades, but I would have assumed that it's because there is a technical advantage to that particular configuration. In a recent article I read, however, the CEO of Seawind Ocean Technology, a wind turbine system development company, argues that for offshore wind turbines, two blades would be more economical and efficient.

The article (June 2017) is an opinion piece on the website Recharge, which describes itself as "The global source for renewable energy news & intelligence." This website is a good source of material for engineers (and teachers of those engineers) who are working in renewable-energy industries. However, one must subscribe to the website to gain access to the articles. The author of the article, Martin Jakubowski, has fortunately also uploaded his article on LinkedIn, where I was able to access it.

The article, "Two-bladed offshore turbines could cut the cost of energy by 50%":
https://www.linkedin.com/pulse/two-bladed-offshore-turbines-could-cut-cost-energy-50-jakubowski

It would be interesting to start a discussion with students about why they think wind turbines have three blades. Jakubowski says that, "Three blades did not become the standard due to technical considerations or a systemic approach to the fundamentals of wind turbines, but because of the trial-and-error approach of the industry's 'garage' pioneers in 1970s Denmark. The three-blade configuration simply worked, so was used repeatedly."

He then goes on to explain why the two-bladed turbine is a better choice, particularly for offshore turbines. In this way, the article follows the conventions of an opinion essay, including many of the phrases used for presenting an argument, making a concession, and giving a rebuttal:
  • And perhaps more importantly ...
  • ..., but this shortfall is more than offset by ...
  • In fact, recent university studies have found that ...
  • It is also worth noting that ...
  • The only relevant disadvantages, ..., are unimportant offshore.
  • Studies show that ...
And a clear conclusion:
  • While developers, financiers and insurers might initially be more wary of two-bladed offshore machines, the potential for increased reliability and LCoE reduction will be hard to ignore. The future will have two blades, not three.

In making his arguments, he uses many comparisons and phrases of cause and effect. Again, these phrases are very useful for students to notice when either writing or presenting support for opinion.

Some examples (with my emphasis):
  • ...two-bladed rotors are better suited for wind turbines because of their flexible configuration - namely, their attachment to the shaft by a flexible hinge.
  • This allows the rotor to have a second degree of freedom: to both rotate (first degree) and to teeter around the axis of the hinge like a seesaw (second degree).
  • This flexible hinge reduces the impact of cyclic loading (fluctuating stresses and strains from the wind), and strongly reduces wear and tear - fatigue - on the components, thus extending the lifetime of the turbine
  • The elasticity of this teetering hinge also removes the need for the blade pitch mechanism - the number-one source of failure in wind turbines - which controls the angle of the blades. Power output can instead be closely controlled by simply yawing (turning) the turbine into or away from the wind.

These are only a few examples; most of the article is written in this way, and is therefore a great source of such material. Notice, also, how the writing focuses on audience by explaining or defining terms that might not be known outside this particular field, e.g., flexible configuration, cyclic loading, yawing.

There are also many collocations that are useful for writing or speaking about other type of technical advantages (with repetitions of produce, reduce, create:
  • produce energy from
  • created a market for
  • reduces the impact of
  • reduces wear and tear
  • extending the lifetime of
  • removes the need for
  • source of failure
  • controlled by
  • reduces the cost of
  • removes the need for
  • potential for increased reliability


Finally, there are many adverbs used in the article, which I particularly like to make my students aware of, since they tend not to use adverbs much in their writing (or confuse them grammatically with adjectives):
  • simply
  • repeatedly
  • likely
  • arguably
  • largely
  • namely
  • strongly
  • closely
  • substantially
  • importantly
  • dramatically
  • costly
  • virtually
  • relatively
  • slightly
  • initially

There are also many useful linking and transition words, including those common to stating arguments (rather than, due to, not ... but because of, yet, however, such as, namely, in fact), but I will leave that to readers to identify.


The only language aspect of the article that I wasn't happy with was the incorrect use of less instead of using fewer in the phrase with less parts. This, in fact, is the same kind of error my students make - using less for both count and noncount nouns. In this case, what would be the best course of action:
  1. change the error before giving the text to the students (good model)
  2. leave the text as it is (authentic source)
  3. tell students there is an error in the use of less/fewer and have them find it (raise awareness)
  4. other choice?

It would be interesting for readers of this blog to give their point of view in the comments - whether engineers, engineering students, or teachers of engineering students.

Friday, August 4, 2017

SpaceX Falcon failure

SpaceX Falcon ready for takeoff
I have written many posts about spacecraft launches; they're interesting topics for my students and they provide a lot of material for language used in technical subjects. A recent event - although an interesting technical topic - has, however, ended in failure.

SpaceX (Space Exploration Technologies Corporation) is a private American aerospace manufacturer and space transport service company. In June it successfully launched two space missions. But the third planned launch on 3 July, the Falcon 9 rocket, was cancelled moments before the engines were to be fired up.

There are, of course, many articles relating to this event. The two I will mention here come from the website "interesting engineering." The first article "SpaceX Scrubs Falcon Launch Due to Computer Issues" includes a webcast of the launch as it happened.

The Link:  http://interestingengineering.com/spacex-scrubs-falcon-launch-due-computer-issues

The webcast is noted to be 22 minutes long, but it doesn't actually start until the 4:26 mark. During the webcast, commentary is provided by John Insprucker, Principal Integration Engineer, who speaks clearly (and seems to have a mid-western American accent).

It includes a bit of waiting at certain points, since it was filmed live. For example, at about the 15 minute mark, the launch is halted. It isn't until the 19 minute mark that some explanation is given, but merely that it was a "GNC-abort," which is described as an automatic computer abort. Further information will have to be used (students can gather this information as homework) to find out exactly what happened.

Since the mission was aborted, there is a lot of vocabulary referring to aspects of this situation, including dfferent ways to indicate that the mission was halted. For example:
  • scrubs the launch
  • due to computer issues
  • looked to continue its streak
  • got scrubbed
  • it was an issue with
  • computers halted the countdown
  • the mission was forced into a 24-hour scrub
  • plans to attempt it again
  • there won't be enough propellant left
  • losing a rocket for the sake of the payload
  • the frustrating scrubbed launch

There are also many different vocabulary items to indicate times and timing:
  • in just nine days
  • at the last minute
  • just moments before
  • at that point
  • attempt it again tomorrow around 7:37
  • ever put into orbit
  • after this launch
  • neither location is set to have launches until
  • scheduled to
  • in a little over a week
  • is planned for August 10
  • when SpaceX will make a supply run
  • tomorrow's launch
  • after takeoff
  • this isn't the company's first time
  • around the 15-minute mark

The second article, "SpaceX Will Try to Launch the Intelsat 35e Satellite Again Today," gives more specific information about the mission and its payload, and has useful collocations.

The link:  http://www.interestingtechnology.net/watch-live-spacex-will-try-launch-intelsat-35e-satellite-today


Some examples of vocabulary that relates well to the first article:
  • abort its mission
  • a technical glitch
  • set to deliver
  • attempt to land
  • ensure it reaches
  • a stabilized landing
  • stripped of its landing hardware
  • maximize its performance
  • reduce the overall weight
  • be launched from
  • be deployed

And vocabulary related to the description of the satellite's payload:
  • deliver high-performance services
  • serve customers
  • placed into service
  • be redeployed to another ... location
  • conditioned to work
  • enables higher efficiency
  • improved throughput
  • composed of
  • manufactured by
  • take ... to the next level

The vocabulary describing aspects of the payload is simply "business" vocabulary, which connects well to this aspect of technology and engineering. It can be useful to recycle such vocabulary when reading or discussing any type of engineering business.