NEWS BEYOND OUR BORDERS : TECH CORNER

Updates to Dam Safety Review Guidelines Address Engineer of Record

APEGBC – APEGBC recently updated its professional practice guidelines for legislated dam safety reviews. The latest version of the Professional Practice Guidelines – Legislated Dam Safety Reviews in BC, version 3.0, is now available on the association’s website.

The guidelines provide the basis for an appropriate standard of care in professional practice when carrying out dam safety reviews. They provide guidance on the specific aspects of dam safety reviews relevant to the governing legislation, Dam Safety Regulation 40/2016, depending upon the purpose of the dam involved.

This latest version of the guidelines reflects recommendations made by the chief inspector of mines and the auditor general in their reports following the Mount Polley dam breach, that there be clarification of the term “Engineer of Record.” A section providing more context on Engineer of Record responsibilities has now been included in the Legislated Dam Safety Reviews in BC guidelines. Additionally, some language in the guidelines has been updated to reflect recent changes to the BC Heath, Safety and Reclamation Code and the Dam Safety Regulation.

The latest version of the Professional Practice Guidelines – Legislated Dam Safety Reviews in BC is available at apeg.bc.ca/guidelines. Questions regarding the updates to the guidelines can directed to Lindsay Steele, P.Geo., Associate Director of Professional Practice at lsteele@apeg.bc.ca.

As Sea Levels Rise, Roman Concrete May Offer Lessons

Engineering360.com – Modern marine concrete structures crumble within decades but 2,000-year-old Roman piers and breakwaters endure and many are stronger than when they were first constructed.

University of Utah geologist Marie Jackson studied the minerals and microscale structures and found that sea water filtering through the concrete leads to the growth of interlocking minerals that lend the concrete added cohesion.

Romans made concrete by mixing volcanic ash with lime and sea water to make a mortar. They then incorporated into that mortar chunks of volcanic rock, the “aggregate” in the concrete.

Modern Portland cement concrete also uses rock aggregate, but with a difference: the sand and gravel particles are intended to be inert. Any reaction with the cement paste could form gels that expand and crack the concrete.

The team concluded that when sea water percolated through Roman concrete in breakwaters and piers, it dissolved components of the volcanic ash and allowed new minerals to grow from the highly alkaline leached fluids.

The crystals have platy shapes that reinforce the cementing matrix. The interlocking plates increase the concrete’s resistance to brittle fracture.

Given the durability advantages of Roman concrete, why isn’t it used more often, particularly since manufacturing of Portland cement produces substantial carbon dioxide emissions?

“The recipe was completely lost,” Jackson says. She has studied ancient Roman texts, but hasn’t yet uncovered the precise methods for mixing the marine mortar, to fully recreate the concrete.

Microbots trap and kill waterborne bacteria

Engineering360.com – When waterborne pathogens prove resistant to conventional disinfectants or when use of chemical agents is not desirable, send out self-propelled microbots decorated with silver nanoparticles.

Researchers engineered Janus, or two-faced, spherical particles to remove bacteria from water. One face is made with magnesium, which reacts with water to produce hydrogen bubbles and propel the micromotors. The other face is made out of alternating iron and gold layers topped by silver nanoparticles. Bacteria stick to the gold and are deactivated by the silver nanoparticles.

Lab testing showed that the particles can motor around in water for 15 to 20 minutes before the magnesium is spent. More than 80 per cent of Escherichia coli in water spiked with a high concentration of the bacteria was trapped. Because of the iron’s magnetic properties, the microbots are easily removed with a magnet, without leaving any waste behind in the water. Tiny, self-propelled robots trap bacteria and could help make water safer to drink.

Factory of the future: N.B. researcher to study 3D-printing powered by thought

Sudbury.com – New Brunswick researchers are plotting what they call the “factories of the future” by developing 3D-printing technologies they said could pave the way for the next industrial revolution.

Mechanical engineer Ed Cyr is studying the applications of artificial intelligence in manufacturing 3D-printed materials as part of a $1.25-million innovation program from the McCain Foundation announced at the University of New Brunswick in Fredericton.

Cyr intends to take the advantages of 3-D printing technology to the next level by developing new behaviours that cannot be found in conventional materials.

For example, he said he is studying a printed aluminum alloy that, when put under certain types of stress, increases in strength far more than a typical sheet metal.

Later in his research, Cyr said he wants to “push the boundaries” of manufacturing by investigating the possibility of 3D-printing powered by thought.

“For a human to sit down and come up with the optimal design, we would have to come up with thousands and thousands and that would be incredibly time consuming,” said Cyr. “The beauty of a computer is it has the ability to go through those thousands and thousands of designs. It can actually model a total design space and tell us which one is the best and it can even come up with things we might not even think of.”

It may seem like the stuff of science fiction, Cyr acknowledged, but he said artificial intelligence is already testing the limits of what we thought possible.

For example, Cyr said researchers in Europe have developed 3D-printing technology for a “bridge (that) could build and design itself.” According to Cyr, the machine scanned the distance the bridge needed to cross, simulated its structure and then printed it.