Research Corner: Interesting Journal Articles

[debunix]

Having read a fair bit of botany lately, this makes total sense, that various compounds will be predictable responses to specific predation. Plants can't get up and walk away from their animal predators, but they are not defenseless.

[LeoFox]

Been trying to understand yan yun (rock melody, see viewtopic.php?p=5995#p5995 ) and so decided to read up on the chemistry and perception of the taste of minerality in wine:

https://www.google.com/url?sa=t&source= ... _O9KOcDaEb

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Interesting passages:

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[pedant]

a new "teapot effect" (dribble effect) fluid dynamics paper!

https://www.cambridge.org/core/journals ... 7E04164575

Developed liquid film passing a smoothed and wedge-shaped trailing edge: small-scale analysis and the ‘teapot effect’ at large Reynolds numbers
Cambridge University Press: 08 September 2021
B. Scheichl, R.I. Bowles, G. Pasias

Recently, the authors considered a thin steady developed viscous free-surface flow passing the sharp trailing edge of a horizontally aligned flat plate under surface tension and the weak action of gravity, acting vertically, in the asymptotic slender-layer limit (J. Fluid Mech., vol. 850, 2018, pp. 924–953). We revisit the capillarity-driven short-scale viscous–inviscid interaction, on account of the inherent upstream influence, immediately downstream of the edge and scrutinise flow detachment on all smaller scales. We adhere to the assumption of a Froude number so large that choking at the plate edge is insignificant but envisage the variation of the relevant Weber number of O(1). The main focus, tackled essentially analytically, is the continuation of the structure of the flow towards scales much smaller than the interactive ones and where it no longer can be treated as slender. As a remarkable phenomenon, this analysis predicts harmonic capillary ripples of Rayleigh type, prevalent on the free surface upstream of the trailing edge. They exhibit an increase of both the wavelength and amplitude as the characteristic Weber number decreases. Finally, the theory clarifies the actual detachment process, within a rational description of flow separation. At this stage, the wetting properties of the fluid and the microscopically wedge-shaped edge, viewed as infinitely thin on the larger scales, come into play. As this geometry typically models the exit of a spout, the predicted wetting of the wedge is related to what in the literature is referred to as the teapot effect.

Teapot effect figure (Scheichl)

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[Bok]

@pedant Nice! An often lamented nuisance on teapots.

[LeoFox]

This paper above is summarized a bit more accessibly by the author here:

https://www.sciencedaily.com/releases/2 ... 120309.htm

"Although this is a very common and seemingly simple effect, it is remarkably difficult to explain it exactly within the framework of fluid mechanics," says Bernhard Scheichl. The sharp edge on the underside of the teapot beak plays the most important role: a drop forms, the area directly below the edge always remains wet. The size of this drop depends on the speed at which the liquid flows out of the teapot. If the speed is lower than a critical threshold, this drop can direct the entire flow around the edge and dribbles down on the outside wall of the teapot.

"We have now succeeded for the first time in providing a complete theoretical explanation of why this drop forms and why the underside of the edge always remains wetted," says Bernhard Scheichl. The mathematics behind it is complicated -- it is an interplay of inertia, viscous and capillary forces. The inertial force ensures that the fluid tends to maintain its original direction, while the capillary forces slow the fluid down right at the beak. The interaction of these forces is the basis of the teapot effect. However, the capillary forces ensure that the effect only starts at a very specific contact angle between the wall and the liquid surface. The smaller this angle is or the more hydrophilic (i.e. wettable) the material of the teapot is, the more the detachment of the liquid from the teapot is slowed down.

[aet]

Theabrownin in puerh

https://pubmed.ncbi.nlm.nih.gov/31273522/

[LeoFox]

Interesting news article

https://www.theguardian.com/sport/2012/ ... stosterone

[filipes]

Very interesting article on effect of water quality on white tea.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5380641/

[LeoFox]

"On January 26th, Professor Anand Yang (International Studies and History) presented a lecture entitled “Commodities and Capitalism: A Tale of Tea in China and India,” as part of the History Department’s 2022 History Lecture Series, Capitalism in Action: Culture, Power, History.

In the lecture, Yang presents a history of capitalism in China and India narrated through the study of a specific commodity, tea. This talk traces the development of tea as a beverage of choice across the modern world and its growth as an industry in Asia. It offers a perspective on the rise of capitalism and globalization that highlights the social, cultural, and economic differentiations and distortions within the capitalist world system. "

https://jsis.washington.edu/southasia/n ... and-india/

[Victoria]

Forensic entomology on a tea leaf’s journey….

There Are a Ridiculous Lot of Invertebrate Traces in Your Cup of Tea
Tessa Koumoundouros 19 June 2022

The bug in a teacup—monitoring arthropod–plant associations with environmental DNA from dried plant material
Henrik Krehenwinkel , Sven Weber , Sven Künzel and Susan R. Kennedy
Published:15 June 2022

Abstract

Environmental DNA analysis (eDNA) has revolutionized the field of biomonitoring in the past years. Various sources have been shown to contain eDNA of diverse organisms, for example, water, soil, gut content and plant surfaces. Here we show that dried plant material is a highly promising source for arthropod community eDNA. We designed a metabarcoding assay to enrich diverse arthropod communities while preventing amplification of plant DNA. Using this assay, we analysed various commercially produced teas and herbs. These samples recovered ecologically and taxonomically diverse arthropod communities, a total of over a thousand species in more than 20 orders, many of them specific to their host plant and its geographical origin. Atypically for eDNA, arthropod DNA in dried plants shows very high temporal stability, opening up plant archives as a source for historical arthropod eDNA. Considering these results, dried plant material appears excellently suited as a novel tool to monitor arthropods and arthropod–plant interactions, detect agricultural pests and identify the geographical origin of imported plant material. The simplicity of our approach and the ability to detect highly diverse arthropod communities from all over the world in tea bags also highlights its utility for outreach purposes and to raise awareness about biodiversity.

[Bok]

This is very interesting, thanks!

[Ethan Kurland]

Forensic entomology on a tea leaf’s journey….

Abstract

The simplicity of our approach and the ability to detect highly diverse arthropod communities from all over the world in tea bags also highlights its utility for outreach purposes and to raise awareness about biodiversity.

1 ordinary teabag has tea from at least a few countries. DNA from how many anthropods, one may wonder? (Never thought I would be typing "anthropods".)

Thanks. Interesting.

[debunix]

I suspect the authors would be more interested in sampling specimens from herbaria than modern teas for better understanding of historical ecosystems, but it would be cool if someone learned about Yunnan's ecology over time by sampling several decades of puerh from one region...

[Masterjeff]

Interesting research on Korean wild tea in Hadong and it's descendant Hadong cultivar.

https://cdnsciencepub.com/doi/pdf/10.4141/CJPS09065

https://www.mdpi.com/1467-3045/46/2/69

[debunix]

Very interesting. Maybe the flavor profile that I so adore in many Balhyochas are from the native wild tea ancestors and not just the processing.

Need to go have some Balhyocha now....once it cools off enough for more hot tea.