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martedì 14 marzo 2023

# gst: porous substrates and foams on the structure of turbulent boundary layers over them.


<< Turbulent flow over and past porous surfaces is encountered in many engineering problems, ranging from flow over forest canopies (..) to flows over and past river beds (..). This makes the understanding or the flow behaviour over porous surfaces crucial. >>
️
<< The present study shows that transition from thick to thin substrate flow behavior depends not only on thickness-to-pore ratio (..) but also on substrate density relative to viscous scales of the flow. >>️

Prateek Jaiswal, Bharathram Ganapathisubramani. Effects of porous substrates on the structure of turbulent boundary layers. arXiv: 2301.04102v1 [physics.flu-dyn]. Jan 10, 2023.

Also

keyword 'turbulence' in FonT

keyword 'turbolento' | 'turbolenza' in Notes (quasi-stochastic poetry)


Keywords: gst, turbulence, turbulent layers, porosity, porous substrates, foam


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Etichette: , , , , ,

mercoledì 8 marzo 2023

# life: apropos of 1or2achoos (from Wuhan), here is a triptych on the subject.


Apropos of 1or2achoos from Wuhan, here is a triptych on the subject. 

( by Rhiannon Williams. The White House is split over covid’s origins. MIT - The Download. Feb 28, 2023. 


(1)
<< The White House said there is no consensus within the Biden administration over the origins of the Covid-19 virus, a day after the disclosure of an Energy Department assessment that the pandemic most likely originated with a leak from a Chinese lab. >>

Josh Chin, Lindsay Wise, Annie Linskey. White House Says No Consensus on Covid Origin. Comments follow Energy Department assessment that pandemic likely started with leak from Chinese lab. WSJ. Feb. 27, 2023. 

(2)
<< The U.S. Energy Department has concluded that the Covid pandemic most likely arose from a laboratory leak, according to a classified intelligence report recently provided to the White House and key members of Congress. The shift by the Energy Department, which previously was undecided on how the virus emerged, is noted in an update to a 2021 document by Director of National Intelligence Avril Haines’s office. >>

Michael R. Gordon, Warren P. Strobel. Lab Leak Most Likely Origin of Covid-19 Pandemic, Energy Department Now Says. U.S. agency’s revised assessment is based on new intelligence. WSJ. Feb. 26, 2023.

(3)
<< Shi Zhengli has spent years at the Wuhan Institute of Virology researching coronaviruses that live in bats. Her work has come under fire as the world tries to understand where covid-19 came from. >>

Jane Qiu. Meet the scientist at the center of the covid lab leak controversy.  MIT Tech Rev. Feb 9, 2022. 

Also

<< Qui l'approccio semplice, diretto, efficace che ho usato per la prevenzione ed eventuale gestione personale dell'entità coronavirus /  SARS-COV-2 (SARS: Severe Acute Respiratory Syndrome ) >>

(Here is the simple, direct, effective approach that I used for the prevention and possible personal management of the coronavirus entity)

# life: aproposito di '1or2achoos' (da Wuhan (?)) ... FonT. Jul 13, 2022. 

Also

keyword 'virus' in FonT

keyword 'virus' in Notes 
(quasi-stochastic poetry)

Keywords:  virus, flu, coronavirus, 2019-ncov, 2019ncov, SARS-CoV-2, sarscov2, covid-19, covid19, 1or2achoos, mask


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giovedì 2 marzo 2023

# gst: when science meets poetry, an image of three-dimensional stepped cracks (bistability, and their transition to simple cracks)


<< Slow cracks may be simple, with no internal structure. The leading edge of a simple crack, the crack front, forms a single fracture plane in its wake. Slow cracks may also develop segmented crack fronts, each segment propagating along a separate fracture plane. These planes merge at locations that form steps along fracture surfaces. Steps are not stationary, but instead propagate within a crack front. Real-time measurements of crack front structure and energy flux reveal that step dynamics significantly increase energy dissipation and drastically alter crack dynamics. Simple and stepped cracks are each stable. By extending the use of energy balance to include 3D crack front structure, (AA) find that, while energy balance is obeyed, it is insufficient to select the energetically favorable crack growth mode. Transitions from stepped cracks to simple cracks occur only when their in-plane front lengths become equal and a perturbation momentarily changes step topology. Such 3D crack dynamics challenge our traditional understanding of fracture. >>

Meng Wang, Mokhtar Adda-Bedia, Jay Fineberg. Dynamics of three-dimensional stepped cracks, bistability, and their transition to simple cracks. Phys. Rev. Research 5, L012001. Jan 9, 2023. 

Also

keyword 'crack' in FonT

keyword 'rottura' | 'crepa' | 'frattura' | 'rugosa' in Notes
(quasi-stochastic poetry)




keywords 'meets poetry' in FonT

Keywords:  gst, transitions, dynamical phase transitions, crack, cracking,   fracture, roughness





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Etichette: , , , , , ,

martedì 28 febbraio 2023

# gst: flocking transitions of unfriendly species.

AA consider << two kinds of self-propelled particles, A and B, that tend to align with particles from the same species and to antialign with the other. The model shows a flocking transition (..) it has a liquid-gas phase transition and displays micro-phase-separation in the coexistence region where multiple dense liquid bands propagate in a gaseous background. >>


<< The interesting features (..) are the existence of two kinds of bands, one composed of mainly A particles and one mainly of B particles, the appearance of two dynamical states in the coexistence region: the PF (parallel flocking) state in which all bands of the two species propagate in the same direction, and the APF (antiparallel flocking) state in which the bands of species A and species B move in opposite directions. When PF and APF states exist in the low-density part of the coexistence region they perform stochastic transitions from one to the other. The system size dependence of the transition frequency and dwell times show a pronounced crossover that is determined by the ratio of the band width and the longitudinal system size. >>

AA << work paves the way for studying multispecies flocking models with heterogeneous alignment interactions. >>

Swarnajit Chatterjee, Matthieu Mangeat, et al. Flocking of two unfriendly species: The two-species Vicsek model. Phys. Rev. E 107, 024607. Feb 14, 2023

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keyword 'swimmers' in FonT

Keywords: gst, flocking, particles, self-propelled particles, swimmers,  microswimmers


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Etichette: , , , , ,

lunedì 27 febbraio 2023

# life: a proposito di bizzarri scenari, qui una transizione 'a gradino' di ipotetico scenario22


Congo Square, New Orleans (img from web).  https://en.m.wikipedia.org/wiki/Congo_Square

Una senz'altro immaginifica transizione di un sistema anch'esso senz'altro immaginifico "3vs3 palle" 

qui potrebbe verificarsi una improvvisa mutazione "3vs3" verso un sistema auto- riconfigurato in "4vs2" palle.

(-) In prima approx il sistema destrogiro "4palle", sebbene caotico,  quasisticastico, potrebbe dimostrare chance di creativa stabilizzazione, anche a medio-lungo termine, anche grazie a non del tutto improbabili episodi di drammatiche funzionali fagocitosi (e.g. nelle forme predatorie del cannibalismo/ auto- cannibalismo, anche orgiastico estremo) al proprio interno.

(-) Il sistema levogiro "2palle" potrebbe invece lui medesimo risultare vincente sull'altro destrogiro nel caso riuscisse nell'im.probabile stabilizzazione,  ristrutturazione funzionale - dimostrando pubblicamente non banali capacità di risoluzione/ reimpostazione di problemi - perciò animandosi in modalità attrattive, coagulative su una parte significativa del 50% di quelle moltitudini verosimilmente costituite da entità fluttuanti nella solitaria condizione di pulviscoli erratici in emarginata sublimazione.

L'immagini, senz'altro campate in aria purtuttavia intriganti:  'episodi di drammatiche funzionali fagocitosi', 'cannibalismo, auto-cannibalismo anche orgiastico estremo' e 'solitaria condizione di pulviscoli erratici in emarginata sublimazione' meriterebbero una serie di poetiche, quasistocastiche perfino

ma mi astengo.

# life: a proposito di bizzarri scenari, qui un ipotetico scenario22 dipinto dal reale ... FonT.  Oct 17,  2022.

Also

<< Tornando all'analogia con la fisica, il potere, come l'energia, muta continuamente di forma >>. In: Onda anti rumore. Notes (quasi-stochastic poetry). April 21, 2005.

keyword 'dance' | 'dancing' in FonT


keyword 'danza' | 'danzant*' in Notes
(quasi-stochastic poetry)



Keywords: life, gst, Congo Square, danza, dance, jazz, Jelly Roll, transition, three-body




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venerdì 24 febbraio 2023

# gst: apropos of transitions, erratic, bursty growth processes in cellular sprawl

<< A new “bursty growth” model for organelles—internal components of biological cells—helps explain observed size fluctuations. >>

<< Biologists have identified within cells many specialized structures called organelles that carry out crucial tasks, but how cells regulate the size and the number of organelles has remained a puzzle. Now, using simulations backed by experiments, biophysicists have demonstrated that cells appear to produce organelles through a seemingly erratic, or “bursty,” growth process, which enables them to control average organelle sizes and numbers while also constraining organelle size variations within any cell. The work helps to build up a more fundamental understanding of the mechanisms of cellular function. >>️

<< We wondered if organelle growth, far from being an orderly ‘brick-by-brick’ assembly, might occur in more random bursts,  (..) The burst model can thus explain how cells balance organelle sizes and numbers while also keeping size fluctuations within a narrow window, >> Shankar Mukherji.

<< This “universal” behavior suggests that the burst mechanism underlies all organelle growth, despite the fact that each organelle has a unique building process. >>️
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Mark Buchanan. Organelle Building Codes. Physics 16, 3. Jan 6, 2023. 

Kiandokht Panjtan Amiri, Asa Kalish, Shankar Mukherji. Robustness and Universality in Organelle Size Control. Phys. Rev. Lett. 130, 018401. Jan 6,  2023. 

Also

keyword 'growth' in FonT

keyword 'erratico' | 'erratica' in Notes
(quasi-stochastic poetry)


keyword 'erratic' in FonT

Keywords: gst, cell, cell assembly, growth, erratic growth, transition



Pubblicato da alle Nessun commento:
Etichette: , , , , ,

giovedì 23 febbraio 2023

# gst: hidden complexity during the twinkle of a shrinking droplet


<< Captivating patterns found in the light scattered by an evaporating water droplet could be used to infer the properties of the droplet as it shrinks. >>

AA << collected the light that bounced off a spherical water droplet as the droplet shrunk, which happened naturally as it evaporated. The team observed twinkling patterns called Fano combs, which resemble the outlines of hedgehogs. >>

Ryan Wilkinson. Twinkling of a Shrinking Droplet Reveals Hidden Complexity. Physics 16, s9. Jan 24, 2023.

AA << then fully explain it by expanding the quantum analogy. This turns the droplet into an “optical atom" with angular momentum, tunneling, and excited states. >>

Javier Tello Marmolejo, Adriana Canales, et al. Fano Combs in the Directional Mie Scattering of a Water Droplet. Phys. Rev. Lett. 130, 043804. Jan 24, 2023.

Also

keyword 'evaporation' in FonT

keyword 'drop' | 'droplet' | 'droploids' in FonT



keyword 'goccia' in Notes 
(quasi-stochastic poetry): 


Keywords: gst, drop, droplet, shrink, shrinking droplet, evaporation, transition


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