Hexbyte Glen Cove Keyhole wasps may threaten aviation safety thumbnail

Hexbyte Glen Cove Keyhole wasps may threaten aviation safety

Hexbyte Glen Cove

Pachodynerus nasidens on 3D-printed De Haviland Dash-8 pitot probe. Credit: House et al (2020) PLOS ONE, CC BY

Over a period of 39 months, invasive keyhole wasps (Pachodynerus nasidens) at the Brisbane Airport were responsible for 93 instances of fully blocked replica pitot probes—vital instruments that measure airspeed—according to a study published November 25 in the open-access journal PLOS ONE by Alan House of Eco Logical Australia and colleagues. As noted by the authors, the results underscore the importance of risk-mitigating strategies, such as covering pitot probes when aircraft arrive and setting up additional traps to intercept the wasps.

Interactions between aircraft and wildlife are frequent and can have serious financial and safety consequences. But the risk posed by wildlife when aircraft are on the ground is much less understood, and specific threats posed by insects have not been quantified before. In the new study, House and his colleagues investigated the possible role of keyhole in obstructing pitot probes at Brisbane Airport. A total of 26 wasp-related issues were reported at the between November 2013 and April 2019, in conjunction with a series of serious safety incidents involving pitot probes. In its native range in South and Central America and the Caribbean, the wasp is known to construct nests using man-made cavities, such as window crevices, electrical sockets, and of course, keyholes.

The researchers used 3-D-printing technology to construct a series of replica pitot probes, which they mounted at four locations at the airport. All nests in these probes were made by keyhole wasps, and peak nesting occurred in the summer months. Nesting success (i.e., the proportion of nests producing live adults) was optimal between 24 and 31°C, and probes with apertures of more than 3 mm in diameter were preferred. The majority of nests were constructed in one area of the airport. The proportion of grassed areas within 1000 m of probes was a significant predictor of nesting, and the volume in pitot probes may determine the sex of emerging wasps. According to the authors, P. nasidens poses a significant risk to , and further work is warranted to develop strategies for controlling or eradicating persistent populations of this adaptable, inventive, and highly mobile species.

The authors add: “We hope this research will bring attention to a little known but serious issue for air travel in tropical and sub-tropical regions. Having found its way across the Pacific Ocean, there is no reason to doubt that it could spread to other parts of Australia. The consequences of not managing this clever but dangerous pest could be substantial.”

More information:
House APN, Ring JG, Shaw PP (2020) Inventive nesting behaviour in the keyhole wasp Pachodynerus nasidens Latreille (Hymenoptera: Vespidae) in Australia, and the risk to aviation safety. PLoS ONE 15(11): e0242063. doi.org/10.1371/journal.pone.0242063

Keyhole wasps may threaten aviation safety (2020, November 26)
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Hexbyte Glen Cove Dissecting colloidal glasses using laser as a lancet thumbnail

Hexbyte Glen Cove Dissecting colloidal glasses using laser as a lancet

Hexbyte Glen Cove

Typical excitation patterns at different pack fractions. Reproduced from Fig.~1b-d of Nature, 11 November 2020 (online). Credit: IBS

Bo Li and Kai Kou, Research Fellows of IBS Center for Soft and Living Matter, together with Walter Kob, Professor of University of Montpellier and Institute Universitaire de France, and Steve Granick, Director of the IBS Center for Soft and Living Matter, report together in Nature that the onset of glass transition is a highly non-trivial process involving complex non-linear responses.

As a substance giving remarkable impetus to both the convenience of our daily life and the advance of modern science and technology, glasses puzzle us, however, on the basic science level. “Glasses see much incremental study but rarely a breakthrough, regardless of the endeavors from generations of scientists,” commented Granick.

The reported non-monotonic dynamical length scale peaking at the onset temperature subverts the prevalent understanding that cage formation is a simple crossover between liquid and glass. “One central question in glass science is the cage formation process that gives the glassy materials their unique optical and ,” said Kob.

“And we directly hit the problem by locally exciting a colloidal glass using ,” said Li.

The emergence of the non-monotonic length scale results from the buildup of domains with cooperative dynamics that become increasingly rigid and start to dominate the particle dynamics. “Just like the painting of Seurat, the mosaic of the dynamical grains and the cage formation is directly related to the merging of them,” says Kob.

“The beauty of science here is that we are able to see how glasses germinate from the liquids microscopically,” Li said.

Displacement fields at various times after the laser excitation, exhibiting the formation of the cooperative grains. Reproduced from Fig.~3e of Nature, 11 November 2020 (online). Credit: IBS

The simple physical picture of the enhanced cooperative dynamics for the non-monotonic response suggests the finding should be general. Kob said, “It’s amazing that the physical rule behind such rich dynamics is so concise.”

Li adds, “Our findings in a well-defined model system will help better understanding other glassy or disordered systems like polymer, granular and atomic glasses, etc.”

In addition to the non-monotonic behavior, a scaling relation between the morphology and size of the excitation pattern is extracted based on a huge amount of experimental data. “The deviation of this relation reflects the degree of a material’s heterogeneity at certain condition,” said Li. Granick remarked, “This scaling law, besides its theoretical importance for physicists, will interest chemists and material scientists as well by offering them a ‘ruler’ that guides the design and synthesis of glass materials.”

Beyond enlightening the first step of glass transition, this proof-of-concept experiment paves the way for the fundamental understanding of glasses eventually. “Using laser as a lancet, a glass sample can be precisely anatomized,” said Granick.

“More and more exotic yet puzzling behaviors in glasses will be assessed in this way,” predicted Kob.

This work is motivated by the long-standing challenges in glass science. The sluggish and highly coupled dynamics always bury the key effect. “If only I could shrink myself, jump into the system and stir the surroundings,” Li said. The femtosecond holographic laser system originally developed by Kou perfectly satisfy the needs of the local excitation. Valuable theoretical support is obtained from Kob for refining the complex experimental observations into concise physical principles. “The highly interdisciplinary environment in our center and successful international collaboration makes a once improbable brainstorm real,” commented Granick.

Granick and Kob concluded, “The field of glass science, being classic but constantly challenging, is promoted by these experiments that elucidate the onset of transition. The conceptual importance of cage-formation for the properties of is revealed. And the micro-rheological approach taken here opens the door to thorough understanding of the glasses one day.”

More information:
Anatomy of cage formation in a 2D glass-forming liquid, Nature (2020). DOI: 10.1038/s41586-020-2869-5 , www.nature.com/articles/s41586-020-2869-5

Dissecting colloidal glasses using laser as a lancet (2020, November 11)
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