Method for Generating Mechanical Linkages of Polygons That Fold Into a Similar Shape

2021 ◽  
Author(s):  
Yohei Yamamoto ◽  
Jun Mitani
Keyword(s):  
Geometrical Constraint ◽  
Similar Shape ◽  
Flat Shape ◽  
Mechanical Linkage

Abstract Origami techniques, as folding and unfolding, can be utilized in shrinkable structures. Especially when the crease pattern is rigid foldable, it can be treated as a mechanical linkage of rigid panels connected by hinges. Since rigid foldable crease patterns have the strong geometrical constraint of the facets not being able to stretch or bend, it is difficult to design new crease patterns, and variations of existing patterns are limited. However, it is known that there are cases where crease patterns can be made rigid foldable by adding some slits. This paper proposes a mechanical linkage that folds into a similar flat shape by adding slits. A method is presented of generating rigid foldable crease patterns in arbitrary polygons that fold smaller, and it is confirmed that structures that have a mechanism for shrinking can be generated from these crease patterns by using rigid thick panels and hinges.

Shrinkable Self-Similar Structure Design

2022 ◽  
pp. 1-10
Author(s):  
Yohei Yamamoto ◽  
Jun Mitani
Keyword(s):  
Structure Design ◽  
Geometrical Constraint ◽  
Flat Shape ◽  
Self Similar ◽  
Mechanical Linkage

Abstract Origami techniques, as folding and unfolding, can be utilized in shrinkable structures. Especially when the crease pattern is rigid foldable, it can be treated as a mechanical linkage of rigid panels connected by hinges. Since rigid foldable crease patterns have the strong geometrical constraint of the facets not being able to stretch or bend, it is difficult to design new crease patterns, and variations of existing patterns are limited. However, it is known that there are cases where crease patterns can be made rigid foldable by adding some slits. This paper proposes a mechanical linkage that folds into a similar flat shape by adding slits. A method is presented of generating rigid foldable crease patterns in arbitrary polygons that fold smaller, and it is confirmed that structures that have a mechanism for shrinking can be generated from these crease patterns by using rigid thick panels and hinges.

scholarly journals LAURENT POLYNOMIAL LANDAU–GINZBURG MODELS FOR COMINUSCULE HOMOGENEOUS SPACES

2021 ◽  
Author(s):  
PETER SPACEK
Keyword(s):  
Homogeneous Space ◽  
Homogeneous Spaces ◽  
Laurent Polynomial ◽  
Complete Intersections ◽  
Laurent Polynomials ◽  
Young Diagrams ◽  
Similar Shape ◽  
Algebraic Torus ◽  
The One ◽  
Polynomial Potentials

AbstractIn this article we construct Laurent polynomial Landau–Ginzburg models for cominuscule homogeneous spaces. These Laurent polynomial potentials are defined on a particular algebraic torus inside the Lie-theoretic mirror model constructed for arbitrary homogeneous spaces in [Rie08]. The Laurent polynomial takes a similar shape to the one given in [Giv96] for projective complete intersections, i.e., it is the sum of the toric coordinates plus a quantum term. We also give a general enumeration method for the summands in the quantum term of the potential in terms of the quiver introduced in [CMP08], associated to the Langlands dual homogeneous space. This enumeration method generalizes the use of Young diagrams for Grassmannians and Lagrangian Grassmannians and can be defined type-independently. The obtained Laurent polynomials coincide with the results obtained so far in [PRW16] and [PR13] for quadrics and Lagrangian Grassmannians. We also obtain new Laurent polynomial Landau–Ginzburg models for orthogonal Grassmannians, the Cayley plane and the Freudenthal variety.

The Use of ELNES for Microanalysis

1999 ◽  
Vol 5 (S2) ◽  
pp. 664-665
Author(s):  
A.J. Craven ◽  
M. MacKenzie
Keyword(s):  
Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy ◽  
Analytical Electron Microscopy ◽  
Local Environment ◽  
Edge Structure ◽  
Similar Shape ◽  
Analytical Electron ◽  
Electron Energy Loss ◽  
Combining Information

The performance of many materials systems depends on our ability to control the distribution of atoms on a nanometre or sub-nanometre scale within those systems. This is as true for steels as it is for semiconductors. A key requirement for improving their performance is the ability to determine the distribution of the elements resulting from processing the material under a given set of conditions. Analytical electron microscopy (AEM) provides a range of powerful techniques with which to investigate this distribution. By combining information from different techniques, many of the ambiguities of interpretation of the data from an individual technique can be eliminated. The electron energy loss near edge structure (ELNES) present on an ionisation edge in the electron energy loss spectrum reflects the local structural and chemical environments in which the particular atomic species occurs. Thus it is a useful contribution to the information available. Since a similar local environment frequently results in a similar shape, ELNES is useful as a “fingerprint”.

Aethycteron n.g. (Monogenea: Ancyrocephalinae) from darters (Percidae: Etheostomatini) in Ontario, Canada with descriptions of A. caerulei n.sp., A. micropercae n.sp., and A. nigrei n.sp. from Etheostoma spp.

1982 ◽  
Vol 60 (6) ◽  
pp. 1397-1407 ◽  
Author(s):  
D. M. Suriano ◽  
M. Beverley-Burton
Keyword(s):  
Type Species ◽  
Accessory Piece ◽  
Generic Diagnosis ◽  
Present Material ◽  
Similar Shape ◽  
Shape And Size

Aethycteron n.g. is proposed for ancyrocephaline monogeneans from darters (Percidae: Etheostomatini): penis enfolded by spiralling sheath incorporating two filaments; accessory piece attached to penis sheath; dorsal and ventral hamuli of similar shape; marginal hooks of similar shape and size. Aethycteron malleus (Mueller, 1938) n.comb. is designated as type species and is redescribed from the present material as is A. moorei (Mizelle, 1940) n.comb. and A. hargisi (Hanek and Fernando, 1972) n.comb. Aethycteron caerulei n.sp., A. micropercae n.sp., and A. nigrei n.sp. are proposed. Aethycteron nigrofasciatus (Harrises, 1962) n. comb., A. ammocryptus (Harrises and Vickery, 1970) n. comb., A. chlorosomus (Harrises and Vickery, 1970) n.comb., A. lottensis (Harrises and Vickery, 1970) n. comb., and A. stigmaeus (Harrises and Vickery, 1970) n.comb. are transferred from Urocleidus Mueller, 1934, the generic diagnosis of which was emended by Suriano and Beverley-Burton in 1981.

Paper 6: Electronic Instrumentation Techniques in the Development of Pistons and Rings

1965 ◽  
Vol 180 (7) ◽  
pp. 54-69 ◽  
Author(s):  
M. H. Westbrook ◽  
R. Munro
Keyword(s):  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Extreme Conditions ◽  
Dynamic Measurements ◽  
Inductive Transducer ◽  
New Type ◽  
Electronic Instrumentation ◽  
Mechanical Linkage ◽  
Contact Displacement ◽  
Engine Development

Both general and particular aspects of the application of electronic instrumentation in internal combustion engine development are discussed, and the work which has been carried out in the authors' establishment on instrumentation for dynamic measurements on the piston assembly is described, in particular, measurements of engine noise and vibration, and of displacement and temperature during operation, using telemetry systems, and making use of both radio and mechanical linkage techniques. The development of a new type of sub-miniature inductive transducer for non-contact displacement measurement under the extreme conditions inside a working piston is described, and the reasons making its development necessary discussed. Results obtained from a working engine showing piston movements as measured by several inductive transducers and transmitted over the linkage system are shown and compared to block vibration recordings made simultaneously; an initial interpretation of the very recent results is made. Finally, electronic methods developed for the static measurement of piston and ring properties are described and the results obtained discussed.

scholarly journals Functional cervicothoracic boundary modified by anatomical shifts in the neck of giraffes

2016 ◽  
Vol 3 (2) ◽  
pp. 150604 ◽  
Author(s):  
Megu Gunji ◽  
Hideki Endo
Keyword(s):  
Cervical Vertebrae ◽  
Cervical Vertebra ◽  
Thoracic Vertebra ◽  
Large Displacement ◽  
Thoracic Vertebrae ◽  
The Novel ◽  
Neck Movement ◽  
Similar Shape ◽  
Seventh Cervical Vertebra ◽  
Longus Colli

Here we examined the kinematic function of the morpho- logically unique first thoracic vertebra in giraffes. The first thoracic vertebra of the giraffe displayed similar shape to the seventh cervical vertebra in general ruminants. The flexion experiment using giraffe carcasses demonstrated that the first thoracic vertebra exhibited a higher dorsoventral mobility than other thoracic vertebrae. Despite the presence of costovertebral joints, restriction in the intervertebral movement imposed by ribs is minimized around the first thoracic vertebra by subtle changes of the articular system between the vertebra and ribs. The attachment area of musculus longus colli , mainly responsible for ventral flexion of the neck, is partly shifted posteriorly in the giraffe so that the force generated by muscles is exerted on the cervical vertebrae and on the first thoracic vertebra. These anatomical modifications allow the first thoracic vertebra to adopt the kinematic function of a cervical vertebra in giraffes. The novel movable articulation in the thorax functions as a fulcrum of neck movement and results in a large displacement of reachable space in the cranial end of the neck. The unique first thoracic vertebra in giraffes provides higher flexibility to the neck and may provide advantages for high browsing and/or male competition behaviours specific to giraffes.

Small vases from Euboean workshops

1963 ◽  
Vol 58 ◽  
pp. 14-19 ◽  
Author(s):  
A. D. Ure
Keyword(s):  
Fourth Century ◽  
Similar Shape ◽  
The One

Perhaps the most popular vase shape in Euboea in the fourth century was the lidded lekanis. A number of specimens, decorated with floral motives on the lid and simple leaves or linear patterns on the receptacles, may be seen in BSA lv, pls. 54–57 passim. They show considerable variety in the shape of the knobs and in the treatment of the handles, but the receptacles remain fundamentally the same. Akin to these are little bowls of similar shape, lidded, but without handles. Such are the vases of a kernos of unknown provenience in Athens with a vaguely anthropomorphic central handle consisting of a long loop surmounted by a moulded head and with small arm-like projections recalling those of a herm (Plate 1, 1). The lids of three of the four little vases are preserved, the two nearest the handle having horizontal rims, while the two outer vases both had lids with rims turning vertically down, as is shown by the one extant lid and by the flanges on both the receptacles. The knobs of the two lids with horizontal rims are of a shape similar to the stemmed foot of a cup or dish; the surviving lid with down-turned rim has a ring like the footring of a stemless cup to serve as a knob. Each kind of knob, stemmed or stemless, functioned as a foot when the lid was set upside down on the table and became a dish. The low footring knobs were not unknown in Athens, but they were commoner in Euboea. One was noticed in BSA lv. 212, no. 8 on a lid, not figured, belonging to the Bonn group of floral black-figure, which is undoubtedly of Euboean, and very probably of Chalcidian manufacture. We shall see more of them later on.

Lengths and topology of alveolar septal borders

1989 ◽  
Vol 67 (5) ◽  
pp. 1930-1940 ◽  
Author(s):  
E. H. Oldmixon ◽  
J. P. Butler ◽  
F. G. Hoppin
Keyword(s):  
Connective Tissue ◽  
Three Dimensional ◽  
Free Standing ◽  
And Topology ◽  
Section Area ◽  
Dimensional Reconstruction ◽  
Alveolar Duct ◽  
Mechanical Linkage ◽  
Alveolar Septa ◽  
Alveolar Parenchyma

To clarify the mechanics of alveolar parenchyma, we undertook a stereological and topological study in perfusion-fixed canine lungs of the borders of alveolar septa. We defined the principal borders as those along which one septum 1) joins two others (J), 2) joins one other at a distinct angle (B), or 3) joins no other structure (E). E and B borders are invariably reinforced with heavy connective tissue cables; J borders are not. Relative net lengths, determined from the number of traces per section area, were J, 45%; E, 19%; and B, 25%. These were remarkably constant over 10 canine lobes (5 animals, 4 volumes). Parenchyma, then, departs from the simple models that comprise only Js and Es. Bs are important; their net length exceeds that of Es. With lobe deflation, E shortened somewhat more than required to maintain geometric similarity, suggesting that the alveolar duct contracted disproportionately. A three-dimensional reconstruction was made from serial sections, and individual border segments were followed through the reconstruction. Typical lengths of individual J, B, and E borders were nearly equal. To characterize how the network of borders were interconnected, we counted the nodes at which they meet by class, e.g., EBE for the meeting of one B, two Es. The most common are JJJJ, 26%; EEEJ, 10%; EBJ, 24%; EBE, 8%; BBJJ, 12%. If parenchyma were constructed only from free-standing entrance rings and septal junctions, only JJJJ and EEEJ would be anticipated. The presence of EBJ, EBE, and BBJJ underscores parenchymal complexity. Only 7% of septa examined were bordered entirely by Js. Connective tissue cables were not confined to the alveolar duct's lumen but often extended to the primary septa at the periphery of the ductal unit. They rarely linked adjacent alveolar ducts; only 1 in 200 cable segments crossed from one duct to another. These observations support the concept that the parenchyma is an elastic network, characterized in part by a serial mechanical linkage from connective tissue cable to septal membrane to cable again.

scholarly journals Experimental migration of knickpoints: influence of style of base-level fall and bed lithology

2016 ◽  
Vol 4 (1) ◽  
pp. 11-23 ◽  
Author(s):  
J.-L. Grimaud ◽  
C. Paola ◽  
V. Voller
Keyword(s):  
Fall Rate ◽  
Pool Depth ◽  
Similar Shape ◽  
Base Level ◽  
Self Organized ◽  
Plunge Pool ◽  
Source To Sink ◽  
Constant Rate ◽  
Geomorphic Features ◽  
River Profiles

Abstract. Knickpoints are fascinating and common geomorphic features whose dynamics influence the development of landscapes and source-to-sink systems – in particular the upstream propagation of erosion. Here, we study river profiles and associated knickpoints experimentally in a microflume filled with a cohesive substrate made of silica, water and kaolinite. We focus on the effect on knickpoint dynamics of varying the distribution of base-level fall (rate, increment, and period) and substrate strength, i.e., kaolinite content. Such simple cases are directly comparable to both bedrock and alluvial river systems. Under a constant rate of base-level fall, knickpoints of similar shape are periodically generated, highlighting self-organized dynamics in which steady forcing leads to multiple knickpoint events. Temporary shielding of the bed by alluvium controls the spacing between these unit knickpoints. Shielding is, however, not effective when base-level drops exceed alluvium thickness. While the base-level fall rate controls the overall slope of experiments, it is not instrumental in dictating the major characteristics of unit knickpoints. Instead the velocity, face slope and associated plunge pool depth of these knickpoints are all strongly influenced by lithology. The period between knickpoints is set by both alluvium thickness and base-level fall rate, allowing use of knickpoint spacing along rivers as an indicator of base-level fall rate.

Shape memory alloy–actuated prestressed composites with application to morphing automotive fender skirts

2018 ◽  
Vol 30 (3) ◽  
pp. 479-494 ◽  
Author(s):  
Venkata Siva C Chillara ◽  
Leon M Headings ◽  
Ryohei Tsuruta ◽  
Eiji Itakura ◽  
Umesh Gandhi ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Design Procedure ◽  
Building Blocks ◽  
Smart Composite ◽  
Thermally Induced ◽  
One Dimensional ◽  
Flat Shape

This work presents smart laminated composites that enable morphing vehicle structures. Morphing panels can be effective for drag reduction, for example, adaptive fender skirts. Mechanical prestress provides tailored curvature in composites without the drawbacks of thermally induced residual stress. When driven by smart materials such as shape memory alloys, mechanically-prestressed composites can serve as building blocks for morphing structures. An analytical energy-based model is presented to calculate the curved shape of a composite as a function of force applied by an embedded actuator. Shape transition is modeled by providing the actuation force as an input to a one-dimensional thermomechanical constitutive model of a shape memory alloy wire. A design procedure, based on the analytical model, is presented for morphing fender skirts comprising radially configured smart composite elements. A half-scale fender skirt for a compact passenger car is designed, fabricated, and tested. The demonstrator has a domed unactuated shape and morphs to a flat shape when actuated using shape memory alloys. Rapid actuation is demonstrated by coupling shape memory alloys with integrated quick-release latches; the latches reduce actuation time by 95%. The demonstrator is 62% lighter than an equivalent dome-shaped steel fender skirt.

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