Reconfigurable Modular Chain: A Reversible Material for Folding Three-Dimensional Lattice Structures

2017 ◽  
Vol 9 (2) ◽  
Author(s):  
Zhe Xu ◽  
Connor McCann ◽  
Aaron M. Dollar
Keyword(s):  
Structural Design ◽  
Three Dimensional ◽  
Space Structures ◽  
Modular Robots ◽  
Lattice Structures ◽  
Rhombic Dodecahedron ◽  
Wide Range ◽  
Different Shapes ◽  
High Level ◽  
Functional Components

A wide range of engineering applications, ranging from civil to space structures, could benefit from the ability to construct material-efficient lattices that are easily reconfigurable. The challenge preventing modular robots from being applied at large scales is mainly the high level of complexity involved in duplicating a large number of highly integrated module units. We believe that reconfigurability can be more effectively achieved at larger scales by separating the structural design from the rest of the functional components. To this end, we propose a modular chainlike structure of links and connector nodes that can be used to fold a wide range of two-dimensional (2D) or three-dimensional (3D) structural lattices that can be easily disassembled and reconfigured when desired. The node geometry consists of a diamondlike shape that is one-twelfth of a rhombic dodecahedron, with magnets embedded on the faces to allow a forceful and self-aligning connection with neighboring links. After describing the concept and design, we demonstrate a prototype consisting of 350 links and experimentally show that objects with different shapes can be successfully approximated by our proposed chain design.

Design of a Reconfigurable Modular Chain for Folding 3D Lattice Structures

2016 ◽  
Author(s):  
Zhe Xu ◽  
Connor McCann ◽  
Aaron M. Dollar
Keyword(s):  
Structural Design ◽  
Space Structures ◽  
Modular Robots ◽  
Lattice Structures ◽  
Engineering Applications ◽  
Rhombic Dodecahedron ◽  
Wide Range ◽  
Different Shapes ◽  
High Level ◽  
Functional Components

A wide range of engineering applications, ranging from civil to space structures, could benefit from the ability to construct material-efficient lattices that are easily reconfigurable. The challenge preventing modular robots from being applied at large scales is mainly the high level of complexity involved in duplicating a large number of highly integrated module units. We believe that reconfigurability can be more effectively achieved at larger scales by separating the structural design from the rest of the functional components. To this end, we propose a modular chain-like structure of links and connector nodes that can be used to fold a wide range of 2D or 3D structural lattices that can be easily disassembled and reconfigured when desired. The node geometry consists of a diamond-like shape that is one twelfth of a rhombic dodecahedron, with magnets embedded on the faces to allow a forceful and self-aligning connection with neighboring links. After describing the concept and design, we demonstrate a prototype consisting of 350 links and experimentally show that objects with different shapes can be successfully approximated by our proposed chain design.

Homogenization of Vibrating Periodic Lattice Structures

2005 ◽  
Author(s):  
Stefano Gonella ◽  
Massimo Ruzzene
Keyword(s):  
Smart Materials ◽  
Periodic Structures ◽  
Three Dimensional ◽  
Periodic Pattern ◽  
Periodic Lattice ◽  
Lattice Structures ◽  
Equivalent Representation ◽  
Detailed Model ◽  
Wide Range ◽  
Unit Cells

The paper describes a homogenization technique for periodic lattice structures. The analysis is performed by considering the irreducible unit cell as a building block that defines the periodic pattern. In particular, the continuum equivalent representation for the discrete structure is sought with the objective of retaining information regarding the local properties of the lattice, while condensing its global behavior into a set of differential equations. These equations can then be solved either analytically or numerically, thus providing a model which involves a significantly lower number of variables than those required for the detailed model of the assembly. The methodology is first tested by comparing the dispersion relations obtained through homogenization with those corresponding to the detailed model of the unit cells and then extended to the comparison of exact and approximate harmonic responses. This comparison is carried out for both one-dimensional and two-dimensional assemblies. The application to three-dimensional structures is not attempted in this work and will be approached in the future without the need for substantial conceptual changes in the theoretical procedure. Hence the presented technique is expected to be applicable to a wide range of periodic structures, with applications ranging from the design of structural elements of mechanical and aerospace interest to the optimization of smart materials with attractive mechanical, thermal or electrical properties.

Multiscale 3D Virtual Dissections of 100-Million-Year-Old Flowers Using X-Ray Synchrotron Micro- and Nanotomography

2014 ◽  
Vol 20 (1) ◽  
pp. 305-312 ◽  
Author(s):  
Jean-David Moreau ◽  
Peter Cloetens ◽  
Bernard Gomez ◽  
Véronique Daviero-Gomez ◽  
Didier Néraudeau ◽  
...  
Keyword(s):  
Phase Contrast ◽  
Three Dimensional ◽  
Multiscale Approach ◽  
X Ray ◽  
Local Tomography ◽  
Transmission Electron ◽  
Wide Range ◽  
Fossil Flowers ◽  
High Level

AbstractA multiscale approach combining phase-contrast X-ray micro- and nanotomography is applied for imaging a Cretaceous fossil inflorescence in the resolution range from 0.75 μm to 50 nm. The wide range of scale views provides three-dimensional reconstructions from the external gross morphology of the inflorescence fragment to the finest exine sculptures of in situ pollen. This approach enables most of the characteristics usually observed under light microscopy, or with low magnification under scanning and transmission electron microscopy, to be obtained nondestructively. In contrast to previous tomography studies of fossil and extant flowers that used resolutions down to the micron range, we used voxels with a 50 nm side in local tomography scans. This high level of resolution enables systematic affinities of fossil flowers to be established without breaking or slicing specimens.

scholarly journals A geometry- and muscle-based control architecture for synthesising biological movement

2021 ◽  
Vol 115 (1) ◽  
pp. 7-37
Author(s):  
Johannes R. Walter ◽  
Michael Günther ◽  
Daniel F. B. Haeufle ◽  
Syn Schmitt
Keyword(s):  
Three Dimensional ◽  
Movement Planning ◽  
Human Model ◽  
Control Architecture ◽  
Joint Angles ◽  
Stick Slip ◽  
Moment Arms ◽  
Wide Range ◽  
High Level ◽  
Structural Layer

AbstractA key problem for biological motor control is to establish a link between an idea of a movement and the generation of a set of muscle-stimulating signals that lead to the movement execution. The number of signals to generate is thereby larger than the body’s mechanical degrees of freedom in which the idea of the movement may be easily expressed, as the movement is actually executed in this space. A mathematical formulation that provides a solving link is presented in this paper in the form of a layered, hierarchical control architecture. It is meant to synthesise a wide range of complex three-dimensional muscle-driven movements. The control architecture consists of a ‘conceptional layer’, where the movement is planned, a ‘structural layer’, where the muscles are stimulated, and between both an additional ‘transformational layer’, where the muscle-joint redundancy is resolved. We demonstrate the operativeness by simulating human stance and squatting in a three-dimensional digital human model (DHM). The DHM considers 20 angular DoFs and 36 Hill-type muscle–tendon units (MTUs) and is exposed to gravity, while its feet contact the ground via reversible stick–slip interactions. The control architecture continuously stimulates all MTUs (‘structural layer’) based on a high-level, torque-based task formulation within its ‘conceptional layer’. Desired states of joint angles (postural plan) are fed to two mid-level joint controllers in the ‘transformational layer’. The ‘transformational layer’ communicates with the biophysical structures in the ‘structural layer’ by providing direct MTU stimulation contributions and further input signals for low-level MTU controllers. Thereby, the redundancy of the MTU stimulations with respect to the joint angles is resolved, i.e. a link between plan and execution is established, by exploiting some properties of the biophysical structures modelled. The resulting joint torques generated by the MTUs via their moment arms are fed back to the conceptional layer, closing the high-level control loop. Within our mathematical formulations of the Jacobian matrix-based layer transformations, we identify the crucial information for the redundancy solution to be the muscle moment arms, the stiffness relations of muscle and tendon tissue within the muscle model, and the length–stimulation relation of the muscle activation dynamics. The present control architecture allows the straightforward feeding of conceptional movement task formulations to MTUs. With this approach, the problem of movement planning is eased, as solely the mechanical system has to be considered in the conceptional plan.

Generating 3D Visual Language Editors: Encapsulating Interaction Techniques in Visual Patterns

2015 ◽  
Vol 25 (02) ◽  
pp. 333-360
Author(s):  
Jan Wolter ◽  
Uwe Kastens
Keyword(s):  
Language Processing ◽  
Three Dimensional ◽  
Basic Structure ◽  
Usability Study ◽  
3D Perception ◽  
Visual Patterns ◽  
Wide Range ◽  
Structure Editor ◽  
High Level ◽  
Study Participants

The implementation of three-dimensional visual languages requires a wide range of conceptual and technical knowledge on issues for 3D graphics and textual language processing. Our generator framework DEViL3D incorporates such knowledge and supports the design of visual 3D languages and their implementation from high-level specifications. Such 3D languages arise from different modeling domains that make use of three-dimensional representations, e.g. the "ball-and-stick" models of molecules. The front-end of a 3D language implementation is a dedicated 3D graphical structure editor, which offers interaction and navigation techniques to construct programs in their domain. These techniques allow to manipulate the 3D program directly using operations to insert, move, and restructure objects. We have developed canned solutions for all such techniques that are encapsulated in visual patterns, which are provided by our generator. The designer of a particular 3D language only has to apply visual patterns to constructs of the abstract syntax, which defines the basic structure of the language. We have complemented our development with a usability study. Participants had to solve several tasks with different interaction or navigation techniques. Furthermore, we equipped the 3D editors with the opportunity to let users gain an immersive 3D perception by using stereoscopic hardware.

Guided surgery with 3D printed device: a case report

2020 ◽  
Author(s):  
Michelle Carvalho de Sales ◽  
Rafael Maluza Flores ◽  
Julianny da Silva Guimaraes ◽  
Gustavo Vargas da Silva Salomao ◽  
Tamara Kerber Tedesco ◽  
...  
Keyword(s):  
Operating Time ◽  
Three Dimensional ◽  
Conventional Technique ◽  
Cervical Region ◽  
Mean Deviation ◽  
Apical Region ◽  
Virtual Planning ◽  
Surgical Guide ◽  
Surgical Guides ◽  
High Level

Dental surgeons need in-depth knowledge of the bone tissue status and gingival morphology of atrophic maxillae. The aim of this study is to describe preoperative virtual planning of placement of five implants and to compare the plan with the actual surgical results. Three-dimensional planning of rehabilitation using software programs enables surgical guides to be specially designed for the implant site and manufactured using 3D printing. A patient with five teeth missing was selected for this study. The patient’s maxillary region was scanned with CBCT and a cast model was produced. After virtual planning using ImplantViewer, five implants were placed using a printed surgical guide. Two weeks after the surgical procedure, the patient underwent another CBCT scan of the maxilla. Statistically significant differences were detected between the virtually planned positions and the actual positions of the implants, with a mean deviation of 0.36 mm in the cervical region and 0.7 mm in the apical region. The surgical technique used enables more accurate procedures when compared to the conventional technique. Implants can be better positioned, with a high level of predictability, reducing both operating time and patient discomfort.

The way of value of Correlation of genomic DNA microsatellite loci and live weight of Chukchi reindeer

2020 ◽  
pp. 27-32
Author(s):  
V. Dodokhov ◽  
N. Pavlova ◽  
T. Rumyantseva ◽  
L. Kalashnikova
Keyword(s):  
Microsatellite Markers ◽  
Agricultural Production ◽  
Live Weight ◽  
Biodiversity Loss ◽  
Tribal Community ◽  
High Germination ◽  
Wide Range ◽  
The Mean ◽  
High Level ◽  
Dna Microsatellite

The article presents the genetic characteristic of the Chukchi reindeer breed. The object of the study was of the Chukchi reindeer. In recent years, the number of reindeer of the Chukchi breed has declined sharply. Reduced reindeer numbers could lead to biodiversity loss. The Chukchi breed of deer has good meat qualities, has high germination viability and is adapted in adverse tundra conditions of Yakutia. Herding of the Chukchi breed of deer in Yakutia are engaged only in the Nizhnekolymsky district. There are four generic communities and the largest of which is the agricultural production cooperative of nomadic tribal community «Turvaurgin», which was chosen to assess the genetic processes of breed using microsatellite markers: Rt6, BMS1788, Rt 30, Rt1, Rt9, FCB193, Rt7, BMS745, C 143, Rt24, OheQ, C217, C32, NVHRT16, T40, C276. It was found that microsatellite markers have a wide range of alleles and generally have a high informative value for identifying of genetic differences between animals and groups of animal. The number of identified alleles is one of the indicators of the genetic diversity of the population. The total number of detected alleles was 127. The Chukchi breed of deer is characterized by a high level of heterozygosity, and the random crossing system prevails over inbreeding in the population. On average, there were 7.9 alleles (Na) per locus, and the mean number of effective alleles (Ne) was 4.1. The index of fixation averaged 0.001. The polymorphism index (PIC) ranged from 0.217 to 0.946, with an average of 0.695.

COVID-19 Outbreak Prediction with Machine Learning

2020 ◽  
Author(s):  
Sina Faizollahzadeh Ardabili ◽  
Amir Mosavi ◽  
Pedram Ghamisi ◽  
Filip Ferdinand ◽  
Annamaria R. Varkonyi-Koczy ◽  
...  
Keyword(s):  
Machine Learning ◽  
Prediction Models ◽  
Fuzzy Inference ◽  
Control Measures ◽  
Future Research ◽  
Complex Nature ◽  
Inference System ◽  
Wide Range ◽  
Standard Models ◽  
High Level

Several outbreak prediction models for COVID-19 are being used by officials around the world to make informed-decisions and enforce relevant control measures. Among the standard models for COVID-19 global pandemic prediction, simple epidemiological and statistical models have received more attention by authorities, and they are popular in the media. Due to a high level of uncertainty and lack of essential data, standard models have shown low accuracy for long-term prediction. Although the literature includes several attempts to address this issue, the essential generalization and robustness abilities of existing models needs to be improved. This paper presents a comparative analysis of machine learning and soft computing models to predict the COVID-19 outbreak as an alternative to SIR and SEIR models. Among a wide range of machine learning models investigated, two models showed promising results (i.e., multi-layered perceptron, MLP, and adaptive network-based fuzzy inference system, ANFIS). Based on the results reported here, and due to the highly complex nature of the COVID-19 outbreak and variation in its behavior from nation-to-nation, this study suggests machine learning as an effective tool to model the outbreak. This paper provides an initial benchmarking to demonstrate the potential of machine learning for future research. Paper further suggests that real novelty in outbreak prediction can be realized through integrating machine learning and SEIR models.

Methodical approaches to managing economic safety of tourism enterprises

2020 ◽  
pp. 160-164
Author(s):  
Leonid Tsubov ◽  
Oresta Shcherban
Keyword(s):  
Safety Management ◽  
Integrated Approach ◽  
Small Enterprise ◽  
Complex Nature ◽  
Efficient Management ◽  
Tourism Enterprises ◽  
High Level ◽  
Functional Components ◽  
Stimulation Control

The set of scientific-methodological tools to secure the mechanism of economic safety management of tourism entrepreneurship is examined as an aggregate of methods, tools, and conceptual activities directed at maintaining the high level of economic safety of tourism entrepreneurship. The features of managing the tourism enterprise and economic safety are analyzed. The basic valuation principles of the reliability and efficiency of the economic safety of the tourism enterprise are determined. The basic tasks of ensuring the economic safety of a small enterprise are outlined. The need to use the integrated approach that secures more opportunities to avoid threats and limits the danger of their emergence is emphasized. The most important principles for securing the economic safety of the tourism enterprise on the microeconomic level are described. Possible practical methods of risk management for the implementation of adopted decisions are proposed. The paper proves the fact that the complex nature of the management of the economic safety of the tourism enterprise and securing the sufficiently efficient management system of detecting and eliminating the threats are provided by the establishment of the management of the economic safety system of the tourism enterprise and its functional components. Research of the methodical approaches to the management of the tourism enterprises’ economic safety allows building and describing the functional structure of the mechanism of management of the tourist enterprise’s economic safety (it is formalized and described by 5 functions: determination of aims; planning; organization and adjusting; motivation and stimulation; control and monitoring).

CRIMINOLOGICAL FEATURES OF CORRUPTION-RELATED CRIMES IN THE FUEL AND ENERGY COMPLEX

2020 ◽  
pp. 23-27
Author(s):  
Сергей Иванович Вележев ◽  
Антон Михайлович Седогин
Keyword(s):  
Legal Protection ◽  
Criminal Activity ◽  
Criminal Cases ◽  
Law Enforcement Agencies ◽  
Energy Complex ◽  
Significant Damage ◽  
Study Results ◽  
Wide Range ◽  
Illegal Activities ◽  
High Level

В представленной статье авторами рассматриваются вопросы уголовно-правовой охраны топливно-энергетического комплекса Российской Федерации от преступных проявлений, в том числе от коррупционной противоправной деятельности должностных лиц. Такие действия причиняют значительный ущерб нормальному функционированию предприятий топливно-энергетического комплекса. Авторами приводятся результаты исследования некоторых криминологических характеристик должностных лиц, совершивших преступления коррупционного характера. Дан анализ причин и условий, способствующих совершению вышеуказанных противоправных действий. Определена типовая модель преступника для данной категории преступлений и его характеристики: в первую очередь, это высокий уровень компетентности, специальное образование и т. д. Авторами отмечается высокий уровень латентной преступности в данной отрасли. Предложены некоторые пути профилактики данной категории правонарушений. Исследование проводилось на основе анализа конкретных уголовных дел, возбужденных следственными органами по результатам оперативно-розыскной деятельности правоохранительных органов. In the article the authors consider the issues of criminal and legal protection of the fuel and energy complex of the Russian Federation from criminal activity including corrupt illegal practices of officials. The authors cite the results of some criminological characteristics study of the fuel and energy complex staff committed corruption crimes. As a result of these illegal actions significant damage is caused to the normal functioning of the fuel and energy enterprises. Such officials` actions determine not only a wide range of other illegal activities, but also lead to public outcry and discredit the industry as a whole. The analysis of the reasons and conditions contributing to the above illegal actions commission is given. A typical model of a criminal for a given crime category and its characteristics are determined. First of all it is a high level competence, special education, etc. A high level of latent crime in this industry is shown. The study results are presented on the example of specific criminal cases initiated by the investigating authorities based on the results of the operation detection activities of law enforcement agencies. Some ways of preventing this category of offenses are proposed.

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