HAMNET Report 1st October 2023

Oh gosh, here’s another Tropical cyclone, this one called KOINU, with maximum wind speeds currently measured at 205km/h active in the north-west Pacific, and threatening about 2 million people in coastal China. It was first announced yesterday and called JENNY by the Philippines, past which it hopefully will slide. It is also forecast to miss Okinawa, so China remains its main target.

It goes without saying that the Western Cape Local Government disaster management centre was activated after last Sunday and Monday’s cut-off low pressure cell produced a rain storm of huge proportions. All districts of the province were severely affected by the rain and stormy conditions, where upwards of 170mm of rain fell in 24 hours. Some 80 roads, passes and bridges were washed away, and, a week later, a large proportion of them haven’t been reopened yet.

Large areas are without water-supplies, ironically enough, after washaways destroyed water supply infrastructure, and electricity supplies were even more erratic than loadshedding already made them.  Masses of holidaying people, who had left the Peninsula to visit areas along the southern Cape Coast over the long weekend couldn’t get back for work or school on Tuesday, and national braai day didn’t happen at all in the Western Cape.

Sadly 15 deaths were reported, but many more rescues were effected, so the emergency organizations are to be congratulated on their excellence over the weekend. Luckily the cut-off low pressure cell was identified and the correct warnings and forecasts made. An estimate of the cost of restoration has, to my knowledge, not yet been made.

By Tuesday, the disaster response of the Western Cape Government to the recent severe weather had shifted from saving lives to recovery and humanitarian aid coordination. And by this weekend, Hermanus had decided to cancel its famous whale festival weekend, because large areas of the town are still without water or electricity!

HAMNET was not formally activated during the rain and flooding, though we have a seat at the disaster management centre during provincial activations.

Now, here’s a report back on last week’s successful arrival of material from the Asteroid BENNU. After travelling 3.86 billion km in a circuitous sort of way back from Bennu, the satellite OSIRIS-Rex dropped its heat-shielded capsule off on the desert floor in Utah, but three minutes ahead of time at 14h52 UTC last Sunday afternoon! After 3.86 billion km, I guess we can forgive OSIRIS-Rex for being a bit off schedule. The 250 grams or so of asteroid material will eventually get to the Johnson Space Centre, before being divvied up and sent to scientists around the world for study. This material is thought to be 4.5 billion years old.

Meanwhile, OSIRIS-Rex fired its rockets to avoid colliding with earth, has changed its name to OSIRIS-APEX, and is now on its way to an infamous asteroid called APOPHIS, which it will reach in 2029. In that year, APOPHIS will come within 31600km of earth, with no chance whatsoever of colliding with us, so please don’t have sleepless nights about it. The satellite will orbit and study APOPHIS for a year and a half.

What a remarkable feat of engineering and navigation!

Writing in TechXplore, Peter Wharton says that his researchers have designed a robot which can change form to tackle varying scenarios.

The team at the University of Bristol and based at the Bristol Robotics Laboratory have built a tetrahedron shaped robot with flexible piping known as Tetraflex that can move through small gaps or over challenging terrain. It can also encapsulate fragile objects (such as an egg) and transport them safely within its soft body.

The findings, (“Tetraflex: A Multigait Soft Robot for Object Transportation in Confined Environments,” published in IEEE Robotics and Automation Letters), show that the Tetraflex robot is capable of locomoting in multiple different ways. This makes the robot potentially useful for mobility in challenging or confined environments such as navigating rubble to reach survivors of an earthquake, performing oil rig inspections or even exploring other planets.

The object transport capability demonstrated also adds another dimension to potential applications. This could be used to pick up and transport payloads from otherwise inaccessible locations, helping with ecological surveying or in nuclear decommissioning.

Lead author Peter Wharton from Bristol’s School of Engineering, Mathematics and Technology explained, “The robot is composed of soft struts connected by rigid nodes. Each strut is formed of an airtight rubber bellow and the length of the strut can be controlled by varying the air pressure within the bellow.

“Higher pressures cause the bellow to extend, and lower pressures cause it to contract. By controlling the pressure in each bellow simultaneously we can control the robot’s shape and size change.

“After this, it was simply a matter of experimenting with different patterns of shape change that would generate useful motions such as rolling or crawling along a surface.”

Their design uses soft struts which can change length freely and independently. By changing the lengths of the struts by the right amount and in the right sequence, they can generate multiple different ways such as rolling or crawling, change the size of the robot, and even envelop and transport payloads.

Peter said, “I would say these capabilities are a natural consequence of working with such a versatile structure and we hope that other interesting capabilities can be developed in the future.

“The most exciting aspect of this study for me is the versatility of Tetraflex and how we might be able to use these robots to explore challenging terrain and achieve tasks in areas humans cannot access. The multiple gaits available to Tetraflex and object transport capability show this versatility well.”

After exploring some capabilities of Tetraflex in locomotion and object transport, the team now plan to apply machine learning algorithms which could allow them to explore movement patterns really thoroughly, as well as optimizing their current ones.

Peter added, “There could be some really creative and effective ways of moving around or interacting with the environment that we haven’t yet discovered.”

This is Dave Reece ZS1DFR reporting for HAMNET in South Africa.