Patterns in Nature
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Quartz Crystal Division of Seiko Instruments Inc
(1) Quartz Crystal Division of Seiko Instruments Inc. and affiliates, which is responsible for manufacturing the products described in this catalogue, holds ISO 9001 and ISO 14001 certification. (2) SII Crystal Technology Inc. Tochigi site holds IATF 16949 certification. Quartz Crystal Product Catalogue Electronic Components Sales Head Office 1-8, Nakase, Mihamaku, Chiba-shi, Chiba 261-8507, Japan Telephone:+81-43-211-1207 Facsimile:+81-43-211-8030 E-mail:[email protected] <Manufacturer> SII Crystal Technology Inc. 1110, Hirai-cho, Tochigi-shi, Tochigi 328-0054, Japan Released in February 2019 No.QTC2019EJ-02C1604 Creating Time - Optimizing Time - Enriching Time Seiko Instruments Inc. (SII), founded in 1937 as a member of the Seiko Group specializing in the manufacture of watches, has leveraged its core competency in high precision watches to create a wide range of new products and technologies. Over the years SII has developed high-precision processed parts and machine tools that pride themselves on their sub-micron processing capability, quartz crystals that came about as a result of our quartz watch R&D, and electronic components such as micro batteries. Optimizing our extensive experience and expertise, we have since diversified into such new fields as compact, lightweight, exceedingly quiet thermal printers, and inkjet printheads, a key component in wide format inkjet printers for corporate use. SII, in the years to come, will maintain an uncompromised dedication to its time-honored technologies and innovations of craftsmanship, miniaturization, and efficiency that meet the needs of our changing society and enrich the lives of those around us. SEIKO HOLDINGS GROUP 1881 1917 1983 1997 2007 K. -
WHAT IS...A Quasicrystal?, Volume 53, Number 8
?WHAT IS... a Quasicrystal? Marjorie Senechal The long answer is: no one is sure. But the short an- diagrams? The set of vertices of a Penrose tiling does— swer is straightforward: a quasicrystal is a crystal that was known before Shechtman’s discovery. But with forbidden symmetry. Forbidden, that is, by “The what other objects do, and how can we tell? The ques- Crystallographic Restriction”, a theorem that confines tion was wide open at that time, and I thought it un- the rotational symmetries of translation lattices in two- wise to replace one inadequate definition (the lattice) and three-dimensional Euclidean space to orders 2, 3, with another. That the commission still retains this 4, and 6. This bedrock of theoretical solid-state sci- definition today suggests the difficulty of the ques- ence—the impossibility of five-fold symmetry in crys- tion we deliberately but implicitly posed. By now a tals can be traced, in the mineralogical literature, back great many kinds of aperiodic crystals have been to 1801—crumbled in 1984 when Dany Shechtman, a grown in laboratories around the world; most of them materials scientist working at what is now the National are metals, alloys of two or three kinds of atoms—bi- Institute of Standards and Technology, synthesized nary or ternary metallic phases. None of their struc- aluminium-manganese crystals with icosahedral sym- tures has been “solved”. (For a survey of current re- metry. The term “quasicrystal”, hastily coined to label search on real aperiodic crystals see, for example, the such theretofore unthinkable objects, suggests the website of the international conference ICQ9, confusions that Shechtman’s discovery sowed. -
Bubble Raft Model for a Paraboloidal Crystal
Syracuse University SURFACE Physics College of Arts and Sciences 9-17-2007 Bubble Raft Model for a Paraboloidal Crystal Mark Bowick Department of Physics, Syracuse University, Syracuse, NY Luca Giomi Syracuse University Homin Shin Syracuse University Creighton K. Thomas Syracuse University Follow this and additional works at: https://surface.syr.edu/phy Part of the Physics Commons Recommended Citation Bowick, Mark; Giomi, Luca; Shin, Homin; and Thomas, Creighton K., "Bubble Raft Model for a Paraboloidal Crystal" (2007). Physics. 144. https://surface.syr.edu/phy/144 This Article is brought to you for free and open access by the College of Arts and Sciences at SURFACE. It has been accepted for inclusion in Physics by an authorized administrator of SURFACE. For more information, please contact [email protected]. Bubble Raft Model for a Paraboloidal Crystal Mark J. Bowick, Luca Giomi, Homin Shin, and Creighton K. Thomas Department of Physics, Syracuse University, Syracuse New York, 13244-1130 We investigate crystalline order on a two-dimensional paraboloid of revolution by assembling a single layer of millimeter-sized soap bubbles on the surface of a rotating liquid, thus extending the classic work of Bragg and Nye on planar soap bubble rafts. Topological constraints require crystalline configurations to contain a certain minimum number of topological defects such as disclinations or grain boundary scars whose structure is analyzed as a function of the aspect ratio of the paraboloid. We find the defect structure to agree with theoretical predictions and propose a mechanism for scar nucleation in the presence of large Gaussian curvature. Soft materials such as amphiphilic membranes, diblock any triangulation of M reads copolymers and colloidal emulsions can form ordered structures with a wide range of complex geometries and Q = X(6 ci)+ X (4 ci)=6χ , (1) − − topologies. -
Crystal Structures and Symmetry 1 Crystal Structures and Symmetry
PHYS 624: Crystal Structures and Symmetry 1 Crystal Structures and Symmetry Introduction to Solid State Physics http://www.physics.udel.edu/∼bnikolic/teaching/phys624/phys624.html PHYS 624: Crystal Structures and Symmetry 2 Translational Invariance • The translationally invariant nature of the periodic solid and the fact that the core electrons are very tightly bound at each site (so we may ignore their dynamics) makes approximate solutions to many-body problem ≈ 1021 atoms/cm3 (essentially, a thermodynamic limit) possible. Figure 1: The simplest model of a solid is a periodic array of valance orbitals embedded in a matrix of atomic cores. Solving the problem in one of the irreducible elements of the periodic solid (e.g., one of the spheres in the Figure), is often equivalent to solving the whole system. PHYS 624: Crystal Structures and Symmetry 3 From atomic orbitals to solid-state bands • If two orbitals are far apart, each orbital has a Hamiltonian H0 = εn, where n is the orbital occupancy ⇐ Ignoring the effects of electronic corre- lations (which would contribute terms proportional to n↑n↓). + +++ ... = Band E Figure 2: If we bring many orbitals into proximity so that they may exchange electrons (hybridize), then a band is formed centered around the location of the isolated orbital, and with width proportional to the strength of the hybridization PHYS 624: Crystal Structures and Symmetry 4 From atomic orbitals to solid-state bands • Real Life: Solids are composed of elements with multiple orbitals that produce multiple bonds. Now imagine what happens if we have several orbitals on each site (ie s,p, etc.), as we reduce the separation between the orbitals and increase their overlap, these bonds increase in width and may eventually overlap, forming bands. -
Crystal Symmetry Groups
X-Ray and Neutron Crystallography rational numbers is a group under Crystal Symmetry Groups multiplication, and both it and the integer group already discussed are examples of infinite groups because they each contain an infinite number of elements. ymmetry plays an important role between the integers obey the rules of In the case of a symmetry group, in crystallography. The ways in group theory: an element is the operation needed to which atoms and molecules are ● There must be defined a procedure for produce one object from another. For arrangeds within a unit cell and unit cells example, a mirror operation takes an combining two elements of the group repeat within a crystal are governed by to form a third. For the integers one object in one location and produces symmetry rules. In ordinary life our can choose the addition operation so another of the opposite hand located first perception of symmetry is what that a + b = c is the operation to be such that the mirror doing the operation is known as mirror symmetry. Our performed and u, b, and c are always is equidistant between them (Fig. 1). bodies have, to a good approximation, elements of the group. These manipulations are usually called mirror symmetry in which our right side ● There exists an element of the group, symmetry operations. They are com- is matched by our left as if a mirror called the identity element and de- bined by applying them to an object se- passed along the central axis of our noted f, that combines with any other bodies. -
Quasicrystals a New Kind of Symmetry Sandra Nair First, Definitions
Quasicrystals A new kind of symmetry Sandra Nair First, definitions ● A lattice is a poset in which every element has a unique infimum and supremum. For example, the set of natural numbers with the notion of ordering by magnitude (1<2). For our purposes, we can think of an array of atoms/molecules with a clear sense of assignment. ● A Bravais lattice is a discrete infinite array of points generated by linear integer combinations of 3 independent primitive vectors: {n1a1 + n2a2 + n3a3 | n1, n2, n3 ∈ Z}. ● Crystal structures = info of lattice points + info of the basis (primitive) vectors. ● Upto isomorphism of point groups (group of isometries leaving at least 1 fixed point), 14 different Bravais lattice structures possible in 3D. Now, crystals... ● Loosely speaking, crystals are molecular arrangements built out of multiple unit cells of one (or more) Bravais lattice structures. ● Crystallographic restriction theorem: The rotational symmetries of a discrete lattice are limited to 2-, 3-, 4-, and 6-fold. ● This leads us to propose a “functional” definition: A crystal is a material that has a discrete diffraction pattern, displaying rotational symmetries of orders 2, 3, 4 and 6. ● Note: Order 5 is a strictly forbidden symmetry → important for us. Tessellations aka tilings Now that we have diffraction patterns to work with, we consider the question of whether a lattice structure tiles or tessellates the plane. This is where the order of the symmetry plays a role. The crystals are special, as they display translational symmetries. As such, the tiling of their lattice structures (which we could see thanks to diffraction patterns) are periodic- they repeat at regular intervals. -
Golden Ratio: a Subtle Regulator in Our Body and Cardiovascular System?
See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/306051060 Golden Ratio: A subtle regulator in our body and cardiovascular system? Article in International journal of cardiology · August 2016 DOI: 10.1016/j.ijcard.2016.08.147 CITATIONS READS 8 266 3 authors, including: Selcuk Ozturk Ertan Yetkin Ankara University Istinye University, LIV Hospital 56 PUBLICATIONS 121 CITATIONS 227 PUBLICATIONS 3,259 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: microbiology View project golden ratio View project All content following this page was uploaded by Ertan Yetkin on 23 August 2019. The user has requested enhancement of the downloaded file. International Journal of Cardiology 223 (2016) 143–145 Contents lists available at ScienceDirect International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard Review Golden ratio: A subtle regulator in our body and cardiovascular system? Selcuk Ozturk a, Kenan Yalta b, Ertan Yetkin c,⁎ a Abant Izzet Baysal University, Faculty of Medicine, Department of Cardiology, Bolu, Turkey b Trakya University, Faculty of Medicine, Department of Cardiology, Edirne, Turkey c Yenisehir Hospital, Division of Cardiology, Mersin, Turkey article info abstract Article history: Golden ratio, which is an irrational number and also named as the Greek letter Phi (φ), is defined as the ratio be- Received 13 July 2016 tween two lines of unequal length, where the ratio of the lengths of the shorter to the longer is the same as the Accepted 7 August 2016 ratio between the lengths of the longer and the sum of the lengths. -
Multidisciplinary Design Project Engineering Dictionary Version 0.0.2
Multidisciplinary Design Project Engineering Dictionary Version 0.0.2 February 15, 2006 . DRAFT Cambridge-MIT Institute Multidisciplinary Design Project This Dictionary/Glossary of Engineering terms has been compiled to compliment the work developed as part of the Multi-disciplinary Design Project (MDP), which is a programme to develop teaching material and kits to aid the running of mechtronics projects in Universities and Schools. The project is being carried out with support from the Cambridge-MIT Institute undergraduate teaching programe. For more information about the project please visit the MDP website at http://www-mdp.eng.cam.ac.uk or contact Dr. Peter Long Prof. Alex Slocum Cambridge University Engineering Department Massachusetts Institute of Technology Trumpington Street, 77 Massachusetts Ave. Cambridge. Cambridge MA 02139-4307 CB2 1PZ. USA e-mail: [email protected] e-mail: [email protected] tel: +44 (0) 1223 332779 tel: +1 617 253 0012 For information about the CMI initiative please see Cambridge-MIT Institute website :- http://www.cambridge-mit.org CMI CMI, University of Cambridge Massachusetts Institute of Technology 10 Miller’s Yard, 77 Massachusetts Ave. Mill Lane, Cambridge MA 02139-4307 Cambridge. CB2 1RQ. USA tel: +44 (0) 1223 327207 tel. +1 617 253 7732 fax: +44 (0) 1223 765891 fax. +1 617 258 8539 . DRAFT 2 CMI-MDP Programme 1 Introduction This dictionary/glossary has not been developed as a definative work but as a useful reference book for engi- neering students to search when looking for the meaning of a word/phrase. It has been compiled from a number of existing glossaries together with a number of local additions. -
The Golden Ratio and the Diagonal of the Square
Bridges Finland Conference Proceedings The Golden Ratio and the Diagonal of the Square Gabriele Gelatti Genoa, Italy [email protected] www.mosaicidiciottoli.it Abstract An elegant geometric 4-step construction of the Golden Ratio from the diagonals of the square has inspired the pattern for an artwork applying a general property of nested rotated squares to the Golden Ratio. A 4-step Construction of the Golden Ratio from the Diagonals of the Square For convenience, we work with the reciprocal of the Golden Ratio that we define as: φ = √(5/4) – (1/2). Let ABCD be a unit square, O being the intersection of its diagonals. We obtain O' by symmetry, reflecting O on the line segment CD. Let C' be the point on BD such that |C'D| = |CD|. We now consider the circle centred at O' and having radius |C'O'|. Let C" denote the intersection of this circle with the line segment AD. We claim that C" cuts AD in the Golden Ratio. B C' C' O O' O' A C'' C'' E Figure 1: Construction of φ from the diagonals of the square and demonstration. Demonstration In Figure 1 since |CD| = 1, we have |C'D| = 1 and |O'D| = √(1/2). By the Pythagorean Theorem: |C'O'| = √(3/2) = |C''O'|, and |O'E| = 1/2 = |ED|, so that |DC''| = √(5/4) – (1/2) = φ. Golden Ratio Pattern from the Diagonals of Nested Squares The construction of the Golden Ratio from the diagonal of the square has inspired the research of a pattern of squares where the Golden Ratio is generated only by the diagonals. -
Phyllotaxis: a Remarkable Example of Developmental Canalization in Plants Christophe Godin, Christophe Golé, Stéphane Douady
Phyllotaxis: a remarkable example of developmental canalization in plants Christophe Godin, Christophe Golé, Stéphane Douady To cite this version: Christophe Godin, Christophe Golé, Stéphane Douady. Phyllotaxis: a remarkable example of devel- opmental canalization in plants. 2019. hal-02370969 HAL Id: hal-02370969 https://hal.archives-ouvertes.fr/hal-02370969 Preprint submitted on 19 Nov 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Phyllotaxis: a remarkable example of developmental canalization in plants Christophe Godin, Christophe Gol´e,St´ephaneDouady September 2019 Abstract Why living forms develop in a relatively robust manner, despite various sources of internal or external variability, is a fundamental question in developmental biology. Part of the answer relies on the notion of developmental constraints: at any stage of ontogenenesis, morphogenetic processes are constrained to operate within the context of the current organism being built, which is thought to bias or to limit phenotype variability. One universal aspect of this context is the shape of the organism itself that progressively channels the development of the organism toward its final shape. Here, we illustrate this notion with plants, where conspicuous patterns are formed by the lateral organs produced by apical meristems. -
Phyllotaxis: Is the Golden Angle Optimal for Light Capture?
Research Phyllotaxis: is the golden angle optimal for light capture? Soren€ Strauss1* , Janne Lempe1* , Przemyslaw Prusinkiewicz2, Miltos Tsiantis1 and Richard S. Smith1,3 1Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne 50829, Germany; 2Department of Computer Science, University of Calgary, Calgary, AB T2N 1N4, Canada; 3Present address: Cell and Developmental Biology Department, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK Summary Author for correspondence: Phyllotactic patterns are some of the most conspicuous in nature. To create these patterns Richard S. Smith plants must control the divergence angle between the appearance of successive organs, Tel: +49 221 5062 130 sometimes to within a fraction of a degree. The most common angle is the Fibonacci or golden Email: [email protected] angle, and its prevalence has led to the hypothesis that it has been selected by evolution as Received: 7 May 2019 optimal for plants with respect to some fitness benefits, such as light capture. Accepted: 24 June 2019 We explore arguments for and against this idea with computer models. We have used both idealized and scanned leaves from Arabidopsis thaliana and Cardamine hirsuta to measure New Phytologist (2019) the overlapping leaf area of simulated plants after varying parameters such as leaf shape, inci- doi: 10.1111/nph.16040 dent light angles, and other leaf traits. We find that other angles generated by Fibonacci-like series found in nature are equally Key words: computer simulation, optimal for light capture, and therefore should be under similar evolutionary pressure. Our findings suggest that the iterative mechanism for organ positioning itself is a more heteroblasty, light capture, phyllotaxis, plant fitness. -
Examples of the Golden Ratio You Can Find in Nature
Examples Of The Golden Ratio You Can Find In Nature It is often said that math contains the answers to most of universe’s questions. Math manifests itself everywhere. One such example is the Golden Ratio. This famous Fibonacci sequence has fascinated mathematicians, scientist and artists for many hundreds of years. The Golden Ratio manifests itself in many places across the universe, including right here on Earth, it is part of Earth’s nature and it is part of us. In mathematics, the Fibonacci sequence is the ordering of numbers in the following integer sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144… and so on forever. Each number is the sum of the two numbers that precede it. The Fibonacci sequence is seen all around us. Let’s explore how your body and various items, like seashells and flowers, demonstrate the sequence in the real world. As you probably know by now, the Fibonacci sequence shows up in the most unexpected places. Here are some of them: 1. Flower petals number of petals in a flower is often one of the following numbers: 3, 5, 8, 13, 21, 34 or 55. For example, the lily has three petals, buttercups have five of them, the chicory has 21 of them, the daisy has often 34 or 55 petals, etc. 2. Faces Faces, both human and nonhuman, abound with examples of the Golden Ratio. The mouth and nose are each positioned at golden sections of the distance between the eyes and the bottom of the chin.