# gst: complexity of a flat-foldings random origami

AA << give the result of approximate enumeration of the total number of flat-foldings of single-vertex origami diagram with random width of angles gathering around the central vertex, and obtain its size dependence for an asymptotic prediction towards the limit of infinite size. >>️

<< In addition, an outlook with respect to the chained determination of local stacking orders of facets caused by the constraint that prohibits the penetration of them is also provided from the viewpoint of organizing the terms included in the physical model. A method to efficiently solve the problem of the determination or enumeration of flat-foldings is discussed based on the above perspectives. >>️

Chihiro Nakajima. An Efficient Enumeration of Flat-Foldings : Study on Random Single Vertex Origami. arXiv: 2409.03240v1 [cond-mat.stat-mech]. Sep 5, 2024.

https://arxiv.org/abs/2409.03240

Also: origami, kirigami, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, origami, kirigami 

# gst: kirigami exposed to external flows.

<< Kirigami patterned materials have found several applications in recent years due to their ability to assume complicated shapes and exhibit emergent physical properties when exposed to external forces. >>️

<< Consisting of an array of cuts in a thin material, fabrication of these patterns can be quite simple. Here (AA) show that when they are placed in fluid flow, kirigami cut sheets with various patterns produce a verity of flow patterns in the wake. Through several sets of experiments, (AA) show that the kirigami sheets placed in flow can undergo static or dynamic flow-induced instabilities as a result of which they can buckle or undergo limit cycle oscillations, or they can remain stable while undergoing very large elongations. >>️

<< The ability to create controlled small-scale vortex shedding, induce desired flow-induced instabilities on structures, and form specifically-angled jets will enable several future applications in flow mixing (e.g., by producing small vortices in uniform flow at low Reynolds numbers), flow control (e.g., by controlling the direction and the number of jets that are produced downstream), and underwater soft robotics (e.g., by imposing desired flow-induced oscillations on structures). >>

️

Adrian G. Carleton, Yahya Modarres-Sadeghi. Kirigami Sheets in Fluid Flow.  arXiv: 2311.09381v1 [physics.flu-dyn]. Nov 15, 2023. 

https://arxiv.org/abs/2311.09381

Also: kirigami, origami, vortex, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, kirigami, origami, fluid flows, vortex

# gst: shape-shifting architecture inspired by metamorphosis, the metamorphosis kirigami system.

<< Kirigami is a variation of origami that involves cutting and folding paper. But while kirigami traditionally uses two-dimensional materials, Yin (Jie Yin) applies the same principles to three-dimensional materials. The metamorphosis system starts with a single unit of 3D kirigami. Each unit can form multiple shapes in itself. But these units are also modular—they can be connected to form increasingly complex structures. Because the individual units themselves can form multiple shapes, and can connect to other units in multiple ways, the overall system is capable of forming a wide variety of architectures. >>

<< The system we've developed was inspired by metamorphosis, (..) With metamorphosis in nature, animals change their fundamental shape. We've created a class of materials that can be used to create structures that change their fundamental architecture. (..) Think of what you can build with conventional materials, (..) Now imagine what you can build when each basic building block is capable of transforming in multiple ways.  (..) The metamorphosis kirigami system does not allow you to disassemble a structure, (..) And because the sides of each cubic unit are rigid and fixed at 90-degree angles, the assembled structure does not bend or flex very much. However, the finished structure is capable of transforming into different architectures.>> Jie Yin.️

Matt Shipman. Inspired by metamorphosis, researchers create materials for shape-shifting architecture. North Carolina State University. Sep 08, 2021. 

https://phys.org/news/2021-09-metamorphosis-materials-shape-shifting-architecture.html  

Yanbin Li, Jie Yin. Metamorphosis of three-dimensional kirigami-inspired reconfigurable and reprogrammable architected matter. Materials Today Physics, 21, 100511. doi: 10.1016/ j.mtphys.2021.100511.

https://www.sciencedirect.com/science/article/abs/pii/S2542529321001723

Also

keyword 'origami' in FonT

https://flashontrack.blogspot.com/search?q=origami

Keywords: gst, origami, kirigami, architecture, bifurcation, metamorphosis,  reconfigurability, reprogrammability.

# gst: apropos of the structure of natural codes, a RNA folding knot (origami-style) dance

 << Every second, a myriad of shapeless strands of RNA fold, origami-style, into intricate structures inside living cells. Now, for the first time, researchers can watch a data-driven video of this folding as RNA molecules are made by the cellular machinery. >> 

<< as the RNA strand grows, it twists, forming knot-like structures. But as more RNA building blocks are added to the strand, the knots unravel, allowing the molecule’s structure to emerge. >> 

Ground-breaking films show RNA’s complex curves take shape. Experimental data and predictive algorithms combine to reveal the essential biomolecule’s shape-shifting.

Nature. Jan 19, 2021. 

https://www.nature.com/articles/d41586-021-00126-8

AA << model the folding of an RNA called SRP, an ancient RNA found in all kingdoms of life. The molecule is well-known for its signature hairpin shape. When watching the videos, the researchers discovered that the molecule ties itself into a knot and unties itself very quickly. Then it suddenly flips into the correct hairpin-like structure using an elegant folding pathway called toehold mediated strand displacement. >>

<< To the best of our knowledge, this has never been seen in nature, (..) We think the RNA has evolved to untie itself from knots because if knots persist, it can render the RNA nonfunctional. The structure is so essential to life that it had to evolve to find a way to get out of a knot. >> Julius Lucks. 

Amanda Morris. New Videos Show RNA as it's Never Been Seen. First-ever data-driven movies illuminate RNA's mysterious folding process.  McCormick School of Engineering. Jan 15, 2021.

https://www.mccormick.northwestern.edu/news/articles/2021/01/new-videos-show-rna-as-its-never-been-seen.html 

https://youtu.be/2XTi9LG9NnU

Angela M Yu, Paul M. Gasper, et al. Computationally reconstructing cotranscriptional RNA folding from experimental data reveals rearrangement of non-native folding intermediates. Molecular Cell. doi: 10.1016/ j.molcel.2020.12.017

Jan 15, 2021. 

https://www.cell.com/molecular-cell/fulltext/S1097-2765(20)30936-9

# gst: dealing with bistability (through hyperbolic paraboloid origami)

<< Origami offers an avenue to program three-dimensional shapes via scale-independent and non-destructive fabrication. >>

Using theoretical model, << which connects geometry to mechanics, (AA) prove that a folded hypar origami exhibits bistability between two symmetric configurations. Further, (AA) tessellate the hypar origami and harness its bistability to encode multi-stable metasurfaces with programmable non-Euclidean geometries. >>

Ke Liu, Tomohiro Tachi, Glaucio H. Paulino. Invariant and smooth limit of discrete geometry folded from bistable origami leading to multistable metasurfaces. Nature Comm. volume 10, Article number: 4238, 17 Sep 17, 2019.    https://www.nature.com/articles/s41467-019-11935-x  

Josh Brown. Hyperbolic paraboloid origami harnesses bistability to enable new applications. Georgia Institute of Technology. Sep 17, 2019.    https://m.techxplore.com/news/2019-09-hyperbolic-paraboloid-origami-harnesses-bistability.html 

# tech: self-assembling origami, smart options for architecture

<< Origami and high-performance textiles are transforming architecture plans for smart human habitats >>

Origami opens up smart options for architecture on the Moon and Mars. Europlanet. Sep 21, 2018.

https://m.phys.org/news/2018-09-origami-smart-options-architecture-moon.html

# gst: the art of designing a self-assembling origami

<< (..) to create smart structures - objects that can collapse, absorb energy, and spring back into place using the geometric principles of origami. >>

<< Smart structures simply change their shape based on a response to a change in the environment. >>

Sophia Fox-Sowell. How origami might reshape the future of everything. Northeastern University. Aug 2, 2018.

https://m.phys.org/news/2018-08-origami-reshape-future.html

Also

"origami"

https://flashontrack.blogspot.com/search?q=origami

gst: some origami won't fold under pressure

<< Why is it difficult to refold a previously folded sheet of paper? [AA] show that even crease patterns with only one designed folding motion inevitably contain an exponential number of "distractor" folding branches accessible from a bifurcation at the flat state >>

Menachem Stern, Matthew B. Pinson, Arvind Murugan. The Complexity of Folding Self-Folding Origami. Phys. Rev. X 7, 041070 – Dec 22, 2017.

https://journals.aps.org/prx/abstract/10.1103/PhysRevX.7.041070

Louise Lerner. Scientists lay out why some origami won't fold under pressure. Jan4, 2018.

https://m.phys.org/news/2018-01-scientists-origami-wont-pressure.html

# gst: origami, strange behaviors hiding in simple structures

<< The Miura-ori is also unique in having what’s called a negative Poisson’s ratio. When you push on its sides, the top and bottom will contract >>

Marcus Woo. The Atomic Theory of Origami. Oct 31, 2017

https://www.quantamagazine.org/the-atomic-theory-of-origami-20171031/

# s-chem: self-assembled also into cuboids

<< Phospholipid liposomes are archetypical self-assembled structures. To minimize the surface tension, the vesicles typically are spherical >>

<< A 1,2-diamidophospholipid is presented that self-assembles into a cuboid structure. Owing to intermolecular hydrogen bonding, the bilayer membranes form an exceptionally tight subgel packing, leading to a maximization of flat structural elements and a minimization of any edges. These conditions are optimized in the geometrical structure of a cube >>

Frederik  Neuhaus, Dennis  Mueller, et al. Vesicle  Origami:  Cuboid  Phospholipid  Vesicles  Formed  by Template-Free  Self-Assembly. Angewandte  Chemie  International  Edition.  Vol. 56,  Issue 23, June  1,  2017. Pages  6515–6518. doi: 10.1002/anie.201701634

http://onlinelibrary.wiley.com/doi/10.1002/anie.201701634/abstract

Phosphorus-containing lipid  molecule self-assembles into a cuboid structure. June  5,  2017

https://m.phys.org/news/2017-06-phosphorus-containing-lipid-molecule-self-assembles-cuboid.html

# s-chem: self-assembling 'origami' nanoscale architectures by DNA staple strands

<< DNA origami is a technique that uses hundreds of short DNA oligonucleotides, called staple strands, to fold a long single-stranded DNA, which is called a scaffold strand, into various designer nanoscale architectures >>

Hong F, Zhang F, et al. DNA Origami: Scaffolds for Creating Higher Order Structures. Chem Rev. 2017 Jun 12. doi: 10.1021/acs.chemrev.6b00825.

https://www.ncbi.nlm.nih.gov/pubmed/28605177

# s-zen-art-chem-tech: Miura-ori approach to self- tessellations

<< Harvard scientist L. Mahadevan and his team have devised a way to make virtually any shape out of a flat sheet of paper, using a fundamental origami or tessellation fold >>

http://www.kurzweilai.net/how-to-make-almost-any-shape-out-of-a-flat-sheet-of-paper

Levi H. Dudte, Etienne Vouga, et al. Programming curvature using origami tessellations. Nature Materials (2016) doi:10.1038/nmat4540

http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat4540.html

# s-tech: DNA as a nano transistor

<< As electronics get smaller they are becoming more difficult and expensive to manufacture, but DNA-based devices could be designed from the bottom-up using directed self-assembly techniques such as ‘DNA origami’ >>

http://www.kurzweilai.net/will-this-dna-molecular-switch-replace-conventional-transistors

Juan Manuel Artés, Yuanhui Li,  et al. Conformational gating of DNA conductance. Nature Communications, 2015; 6: 8870 DOI: 10.1038/ncomms9870

http://www.nature.com/ncomms/2015/151209/ncomms9870/full/ncomms9870.html

# rmx-s-tech: origami swans from power papers

<< One sheet, 15 centimetres in diameter and a few tenths of a millimetre thick can store as much as 1 F, which is similar to the supercapacitors currently on the market. The material can be recharged hundreds of times and each charge only takes a few seconds. >>

http://www.liu.se/forskning/forskningsnyheter/1.662150?l=en&sc=true

Abdellah Malti, Jesper Edberg, et al. An Organic Mixed Ion-Electron Conductor for Power Electronics.  Advanced Science, DOI 10.1002/advs.201500305

http://onlinelibrary.wiley.com/doi/10.1002/advs.201500305/abstract

# rmx-p-it-sx: rimembranze di scolastiche tecniche applicazioni: l'afflati su carta di Nico, l'orlettature a maglina su legno di Lucia ...

<<  (..) compone origami con un foglio di carta, mentre parla con qualche collega: “Che dobbiamo dire… È solo l’inizio. Qua può succedere di tutto” >>

Nico Stumpo - http://m.huffpost.com/it/entry/8535522

<< (..)  marcio non era solo il portone ma l'intero Regno >>

Lucia Annunziata - http://m.huffpost.com/it/entry/8534448