scholarly journals Reconfigurable Disk-like Microswarm under a Sawtooth Magnetic Field

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1529
Author(s):  
Tao Zhang ◽  
Yuguo Deng ◽  
Bo Zhou ◽  
Jiayu Liu ◽  
Yufeng Su ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Targeted Delivery ◽  
Robotic Systems ◽  
Chain Mechanism ◽  
Practical Applications ◽  
Magnetic Chain ◽  
Pattern Stability ◽  
Morphological Transformations ◽  
High Level ◽  
Shed Light

Swarming robotic systems, which stem from insect swarms in nature, exhibit a high level of environmental adaptability and enhanced tasking capabilities for targeted delivery and micromanipulation. Here, we present a strategy that reconfigures paramagnetic nanoparticles into microswarms energized by a sawtooth magnetic field. A rotary-stepping magnetic-chain mechanism is proposed to address the forming principle of disk-like swarms. Based on programming the sawtooth field, the microswarm can perform reversible transformations between a disk, an ellipse and a ribbon, as well as splitting and merging. In addition, the swarms can be steered in any direction with excellent maneuverability and a high level of pattern stability. Under accurate manipulation of a magnetic microswarm, multiple microparts with complicated shapes were successfully combined into a complete assembly. This reconfigurable swarming microrobot may shed light on the understanding of complex morphological transformations in living systems and provide future practical applications of microfabrication and micromanipulation.

scholarly journals Self-Propelled Janus Microdimer Swimmers under a Rotating Magnetic Field

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1672 ◽  
Author(s):  
Shimin Yu ◽  
Ningze Ma ◽  
Hao Yu ◽  
Haoran Sun ◽  
Xiaocong Chang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Rotating Magnetic Field ◽  
Robotic Systems ◽  
Maximum Speed ◽  
Complex Environments ◽  
Field Frequency ◽  
Practical Applications ◽  
Non Invasive ◽  
Remote Actuation ◽  
The Magnetic Field

Recent strides in micro- and nanofabrication technology have enabled researchers to design and develop new micro- and nanorobots for biomedicine and environmental monitoring. Due to its non-invasive remote actuation and convenient navigation abilities, magnetic propulsion has been widely used in micro- and nanoscale robotic systems. In this article, a highly efficient Janus microdimer swimmer propelled by a rotating uniform magnetic field was investigated experimentally and numerically. The velocity of the Janus microdimer swimmer can be modulated by adjusting the magnetic field frequency with a maximum speed of 133 μm·s−1 (≈13.3 body length s−1) at the frequency of 32 Hz. Fast and accurate navigation of these Janus microdimer swimmers in complex environments and near obstacles was also demonstrated. This efficient propulsion behavior of the new Janus microdimer swimmer holds considerable promise for diverse future practical applications ranging from nanoscale manipulation and assembly to nanomedicine.

scholarly journals Tunable Adhesion of a Bio-Inspired Micropillar Arrayed Surface Actuated by a Magnetic Field

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Xingji Li ◽  
Zhilong Peng ◽  
Yazheng Yang ◽  
Shaohua Chen
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Rotation Angle ◽  
Adhesion Force ◽  
Practical Applications ◽  
Section Shape ◽  
Theoretical Predictions ◽  
Large Elastic Deformation ◽  
The Difference

Bio-inspired functional surfaces attract many research interests due to the promising applications. In this paper, tunable adhesion of a bio-inspired micropillar arrayed surface actuated by a magnetic field is investigated theoretically in order to disclose the mechanical mechanism of changeable adhesion and the influencing factors. Each polydimethylsiloxane (PDMS) micropillar reinforced by uniformly distributed magnetic particles is assumed to be a cantilever beam. The beam's large elastic deformation is obtained under an externally magnetic field. Specially, the rotation angle of the pillar's end is predicted, which shows an essential effect on the changeable adhesion of the micropillar arrayed surface. The larger the strength of the applied magnetic field, the larger the rotation angle of the pillar's end will be, yielding a decreasing adhesion force of the micropillar arrayed surface. The difference of adhesion force tuned by the applied magnetic field can be a few orders of magnitude, which leads to controllable adhesion of such a micropillar arrayed surface. Influences of each pillar's cross section shape, size, intervals between neighboring pillars, and the distribution pattern on the adhesion force are further analyzed. The theoretical predictions are qualitatively well consistent with the experimental measurements. The present theoretical results should be helpful not only for the understanding of mechanical mechanism of tunable adhesion of micropillar arrayed surface under a magnetic field but also for further precise and optimal design of such an adhesion-controllable bio-inspired surface in future practical applications.

MANAGERS CAN ALSO RESIST CHANGES — CAN WE DEAL WITH THIS? AN EXPLORATORY STUDY FROM JAPAN

2013 ◽  
Vol 21 (04) ◽  
pp. 447-493
Author(s):  
BALÁZS VASZKUN
Keyword(s):  
Traditional Values ◽  
Traditional Management ◽  
Japanese Firms ◽  
Work Routines ◽  
The Status ◽  
Major Reform ◽  
Mass Recruitment ◽  
Dominant Coalition ◽  
High Level ◽  
Shed Light

Japan is going through a transformation, yet it is difficult to judge which model should be chosen as a direction to go in with corporate reforms. Badly needed initiatives seeking to replace outdated managerial habits by new best practices in Japanese firms are being jeopardized by organizational members whose goal is to maintain the status quo — in terms of both political power and everyday work routines. Yet managerial habits and behaviours need to change if Japanese firms are to be entrepreneurial and innovative. According to institutionalism, blocking new initiatives is normal, and societal support is needed for major reform attempts. The focus of this paper is to shed light on how society in Japan is divided when it comes to large firms altering practices with which they have been traditionally managed. Our proposition is that complex, multi-element reform packages — having a potentially opposing dominant coalition, which is the case of Japan — ought to be implemented following a well-defined, prioritized listing of elements. After examining an attitude survey carried out in Japan, our findings revealed two clusters with a particularly high level of support for traditional management. Moreover, out of the two, one appeared to be extremely passive and resistant to any sort of change. In order to fight general resistance and reform outdated practices, our survey shows that Japan could move further towards a system compensating performance rather than seniority and giving more chance to women, discarding mass-recruitment, slow promotion whilst also maintaining the most deeply-rooted traditional values such as job security, paternalism or harmony in corporate life.

Pattern generation and motion control of a vortex-like paramagnetic nanoparticle swarm

2018 ◽  
Vol 37 (8) ◽  
pp. 912-930 ◽  
Author(s):  
Jiangfan Yu ◽  
Lidong Yang ◽  
Li Zhang
Keyword(s):  
Magnetic Field ◽  
Targeted Delivery ◽  
Pitch Angle ◽  
Dynamic Equilibrium ◽  
Equilibrium Structure ◽  
Pattern Generation ◽  
Analytical Models ◽  
Generation Process ◽  
Rotating Magnetic Fields ◽  
Small Pitch

Controlling a swarm of microrobots with external fields is one of the major challenges for untethered microrobots. In this work, we present a new method to generate a vortex-like paramagnetic nanoparticle swarm (VPNS) from dispersed nanoparticles with a diameter of 500 nm, using rotating magnetic fields. The VPNS exhibits a dynamic-equilibrium structure, in which the nanoparticles perform synchronized motions. The mechanisms of the pattern-generation process are analyzed, simulated, and validated by experiments. By tuning the rotating frequency of the input magnetic field, the pattern of a VPNS changes accordingly. Analytical models for estimating the areal change of the pattern are proposed, and they have good agreement with the experimental data. Moreover, reversible merging and splitting of vortex-like swarms are demonstrated and investigated. Serving as a mobile robotic end-effector, a VPNS is capable of making locomotion by tuning the pitch angle of the actuating rotating field. With a small pitch angle, e.g. 2°, the whole swarm moves as an entity, and the shape of the pattern remains intact. In addition, the trapping forces of VPNSs are verified, showing the critical input parameters of the magnetic field that affect the morphology of the swarm. Finally, we demonstrate that VPNSs pass through curved and branched channels with high positioning precision, and the access rates for targeted delivery are over 90%, which are significantly higher than those in the cases of particle swarms moving with tumbling motions.

scholarly journals A methodological roadmap to quantify animal-vectored spatial ecosystem subsidies

2020 ◽  
Author(s):  
Diego Ellis-Soto ◽  
Kristy M. Ferraro ◽  
Matteo Rizzuto ◽  
Emily Briggs ◽  
Julia D. Monk ◽  
...  
Keyword(s):  
Animal Movement ◽  
Open Systems ◽  
Nutrient Transport ◽  
Ecosystem Dynamics ◽  
Ecosystem Impacts ◽  
Practical Applications ◽  
Ecosystem Theory ◽  
Spatio Temporal ◽  
High Level ◽  
Tracking Devices

Ecosystems are open systems connected through spatial flows of energy, matter, and nutrients. Predicting and managing ecosystem interdependence requires a rigorous quantitative understanding of the drivers and vectors that connect ecosystems across spatio-temporal scales. Animals act as such vectors when they transport nutrients across landscapes in the form of excreta, egesta, and their own bodies. Here, we introduce a methodological roadmap that combines movement, foraging, and ecosystem ecology to study the effects of animal-vectored nutrient transport on meta-ecosystems. The meta-ecosystem concept — the notion that ecosystems are connected in space and time by flows of energy, matter, and organisms across boundaries — provides a theoretical framework on which to base our understanding of animal-vectored nutrient transport. However, partly due to its high level of abstraction, there are few empirical tests of meta-ecosystem theory, and while we may label animals as important mediators of ecosystem services, we lack predictive inference of their relative roles and impacts on diverse ecosystems. Recently developed technologies and methods — tracking devices, mechanistic movement models, diet reconstruction techniques and remote sensing — have the potential to facilitate the quantification of animal-vectored nutrient flows and increase the predictive power of meta-ecosystem theory. Understanding the mechanisms by which animals shape ecosystem dynamics may be important for ongoing conservation, rewilding, and restoration initiatives around the world, and for more accurate models of ecosystem nutrient budgets. We provide conceptual examples that show how our proposed integration of methodologies could help investigate ecosystem impacts of animal movement. We conclude by describing practical applications to understanding cross-ecosystem contributions of animals on the move.

scholarly journals An Assessment of the Reliability of the NIGNET Data

2019 ◽  
Vol 3 (1) ◽  
pp. 18-29
Author(s):  
E. G. Ayodele ◽  
C. J. Okolie ◽  
O. A. Mayaki
Keyword(s):  
National Development ◽  
Accurate Information ◽  
Positional Accuracy ◽  
Data Archiving ◽  
Practical Applications ◽  
3 Dimensional ◽  
Gnss Network ◽  
High Level ◽  
Gnss Data ◽  
Geodetic Reference Frame

The Nigerian Geodetic Reference Frame is defined by a number of Continuously Operating Reference Stations (CORS) that constitute the Nigerian GNSS Network (NIGNET). NIGNET is essential for planning and national development with the main goal of ensuring consistency in the geodetic framework both nationally and internationally. Currently, the strength of the network in terms of data reliability has not been adequately studied due to the fact that research into CORS in Nigeria is just evolving, which constitutes a limitation in its applications. Therefore, the aim of this research is to explore the reliability of the 3-dimensional coordinates of NIGNET to inform usability and adequacy for both scientific and practical applications. In particular, this study examines if the 3-dimensional coordinates of NIGNET are equally reliable in terms of positional accuracy. Accordingly, this study utilised GNSS data collected over a period of six years (2011 – 2016) from the network to compute the daily geocentric coordinates of the stations. Exploratory and statistical data analysis techniques were used to understand the magnitude of the errors and the accuracy level in the 3-dimensional coordinates. For this purpose, accuracy metrics such as standard deviation (𝜎), standard error (𝑆𝐸) and root mean square error (RMSE) were computed. While One-way ANOVA was conducted to explore the coordinate differences. The results obtained showed that SE and RMSE ranged from 13.00 − 56.50𝑚𝑚 and 14.38 − 73.16𝑚𝑚 respectively, which signifies high accuracy. Overall, while 88% of the network showed a high level of positional accuracy, the reliability has been compromised due to excessive gaps in the data archiving. Therefore, due attention must be given to NIGNET to achieve its purpose in the provision of accurate information for various geospatial applications. Also, any efforts directed at understanding the practical implications of NIGNET must be well-embraced for the realization of its set objectives.

scholarly journals Field (In)dependence Flexibility Following a Virtual Immersion Is Associated With Cybersickness and Sense of Presence

2021 ◽  
Vol 2 ◽  
Author(s):  
A. Maneuvrier ◽  
L. M. Decker ◽  
P. Renaud ◽  
G. Ceyte ◽  
H. Ceyte
Keyword(s):  
Visual Cues ◽  
Subjective Experience ◽  
A Posteriori ◽  
Future Studies ◽  
Sense Of Presence ◽  
Before And After ◽  
High Level ◽  
Shed Light ◽  
Rod And Frame Test ◽  
Rod And Frame

Field dependence–independence (FDI) is a psychological construct determining an individual’s approach of the perception–cognition coupling. In virtual reality (VR) context, several studies suggest that an individual’s perceptive style is susceptible to shift toward a more FI mode through down-weighting of conflicting visual cues. The present study proposes to investigate the potential flexible nature of FDI following a virtual immersion and to assess if this flexibility might be associated with the subjective experience of VR. 86 participants explored a real-world–like virtual environment for approximately 10 min. FDI levels were measured before and after the VR exposure using the rod-and-frame test. Their subjective experience of VR was measured a posteriori (cybersickness and sense of presence) and used in order to build two experimental groups via a cluster analysis. The results showed that only participants with a poor subjective experience of VR (i.e., a low level of sense of presence associated with a high level of cybersickness) significantly shifted to a more FI mode, which is discussed as a sensory re-weighting mechanism. Pragmatical applications are discussed, and future studies are outlined, based on the conclusion that FDI might be more flexible than we thought, which could shed light on the psychophysiology of VR.

scholarly journals The Magnetoelectric Effect of a Ni0.3Zn0.62Cu0.08Fe2O4 - PbFe0.5Nb0.5O3 Multilayer Composite

2014 ◽  
Vol 59 (3) ◽  
pp. 1011-1015
Author(s):  
P. Guzdek ◽  
M. Sikora ◽  
Ł. Góra ◽  
Cz. Kapusta
Keyword(s):  
Magnetic Field ◽  
Magnetoelectric Effect ◽  
Magnetic Hysteresis ◽  
Tape Casting ◽  
Casting Process ◽  
Layered Composites ◽  
Practical Applications ◽  
Magnetoelectric Composite ◽  
Sinusoidal Magnetic Field ◽  
Magnetoelectric Coefficient

Abstract The magnetoelectric effect in multiferroic materials has been widely studied for its fundamental interest and practical applications. The magnetoelectric effect observed for single phase materials like Cr2O3, BiFeO3, and Pb(Fe0.5Nb0.5)O3 is usually small. A much larger effect can be obtained in composites consisting of magnetostrictive and piezoelectric phases. This paper investigates the magnetoelectric effect of a multilayer (laminated) structure consisting of 6 nickel ferrite and 7 PFN relaxor layers. It describes the synthesis and tape casting process for Ni0.3Zn0.62Cu0.08Fe2O4 ferrite and relaxor PbFe0.5Nb0.5O3 (PFN). Magnetic hysteresis, ZFC - FC curves and dependencies of magnetization versus temperature for PFN relaxor and magnetoelectric composite were measured with a vibrating sample magnetometer (VSM) in an applied magnetic field up to 85 kOe at a temperature range of 10 – 400 K. Magnetoelectric effect at room temperature was investigated as a function of a static magnetic field (0.3 - 6.5 kOe) and the frequency of sinusoidal magnetic field (0.01 - 6.5 kHz). At lower magnetic field, the magnetoelectric coefficient increases slightly before reaching a maximum and then decreases. The magnetoelectric coefficient aME increases continuously as the frequency is raised, although this increase is less pronounced in the 1-6.5 kHz range. Maximum values of the magnetoelectric coefficient attained for the layered composites exceed about 50 mV/(Oe cm).

scholarly journals Fast Drivable Areas Estimation with Multi-Task Learning for Real-Time Autonomous Driving Assistant

2021 ◽  
Vol 11 (22) ◽  
pp. 10713
Author(s):  
Dong-Gyu Lee
Keyword(s):  
Real Time ◽  
Computational Efficiency ◽  
Autonomous Driving ◽  
Learning Approaches ◽  
Practical Applications ◽  
Task Learning ◽  
Lane Line ◽  
High Level ◽  
Time Autonomous

Autonomous driving is a safety-critical application that requires a high-level understanding of computer vision with real-time inference. In this study, we focus on the computational efficiency of an important factor by improving the running time and performing multiple tasks simultaneously for practical applications. We propose a fast and accurate multi-task learning-based architecture for joint segmentation of drivable area, lane line, and classification of the scene. An encoder-decoder architecture efficiently handles input frames through shared representation. A comprehensive understanding of the driving environment is improved by generalization and regularization from different tasks. The proposed method learns end-to-end through multi-task learning on a very challenging Berkeley Deep Drive dataset and shows its robustness for three tasks in autonomous driving. Experimental results show that the proposed method outperforms other multi-task learning approaches in both speed and accuracy. The computational efficiency of the method was over 93.81 fps at inference, enabling execution in real-time.

scholarly journals The International School of Crystallography: an example of continuing education

2014 ◽  
Vol 70 (a1) ◽  
pp. C1274-C1274
Author(s):  
Annalisa Guerri ◽  
Giovanna Scapin ◽  
Paola Spadon
Keyword(s):  
Interpersonal Relationships ◽  
Public Awareness ◽  
International School ◽  
Theoretical Background ◽  
Great Success ◽  
Practical Applications ◽  
Local Staff ◽  
School Teaching ◽  
Traditional Lectures ◽  
High Level

2014 has been declared by UNESCO the International Year of Crystallography. Following the declaration, many initiatives have flourished with the intent of spreading the science and culture of crystallography, since among the major objectives of the IYCr2014 are increase of public awareness on the science of crystallography, promotion of education and research in all fields of crystallography and fostering of international collaborations. The International School of Crystallography is an internationally recognized meeting that was started in 1974 by Prof. Riva di Sanseverino, with the similar goals of promoting high level crystallographic education, scientific exchanges and collaborations. In 2014 the school celebrates its 40th year of activity. During these forty years, courses have been held on many different topics addressing all aspects of crystallography, from crystal growth theory to practical applications in drug discovery to the use of cutting edge technologies; students and teachers have been brought together in an environment that fostered high level scientific discussions as well as unique interpersonal relationships. Many of the students moved on to become well known personality in the crystallographic community, while retaining collaborations and friendships started during the School. Through these years the School teaching methods have also evolved, taking advantage of the fast technological progress of the past 10 years or so. The School offers both traditional lectures and practical computer-based workshops, to guarantee the students not only a theoretical background, but also hands-on experiences on applied crystallography. The dedication of the organizers and lecturers, the unconditioned support of the local staff, and the unique location of the School have made it a great success and a very popular meeting for generations of crystallographers.

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