attractive force
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Yuki Taoka ◽  
Terumichi Hayashi ◽  
Pasomphone Hemthavy ◽  
Kunio Takahashi ◽  
Shigeki Saito

Abstract This study proposes and verifies bipolar electrostatic grippers stacking 3D-printed-layered modules consisting of arrays of elastically deformable bipolar beams. The influence of the mechanical compliance of grippers on the attractive force that it generates is clarified by comparing two types of modules having either high or low mechanical compliances. Experiments measured the attractive force of the gripper and demonstrated the pick-and-place performance of a thin film. The results show that mechanical compliance plays an important role in mitigating the attractive force decrease in stacking modules. The grippers’ ability for thin film handling is demonstrated by observing pick-and-place behaviours of the proposed bipolar electrostatic grippers.

2021 ◽  
Vol 33 (6) ◽  
pp. 1349-1358
Yoshiyuki Higashi ◽  
Kenta Yamazaki ◽  
Arata Masuda ◽  
Nanako Miura ◽  

This paper presents an attractive force estimation system and an automatic activation system for an electropermanent magnet (EPM) for an inspection UAV. Adsorption to infrastructures for inspection at a distance is extremely difficult to perform safely because the operator cannot detect the state of adsorption of the drone equipped with a magnetic adsorption device. Therefore, in this paper, we clarify the relationship between the magnetic flux density and attractive force of the EPM through experiments, and develop an estimation algorithm for the attractive force based on the results. An automatic activation system, using the induced voltage in the coil when the EPM approaches the magnetic substance, is developed and mounted on a quadrotor for a flight experiment along with the estimation system for the attractive force. The developed system is verified using flight and adsorption experiments on the quadrotor.

Scott Shinabargar

The recurring pastiches of journalistic writing in Max Jacob’s seminal collection are more complex than they initially appear—critical, not merely of this discourse’s supposed objectivity, but of the assumption that the transmission of valid, valuable news is ever really sought in the first place. The indiscretions of sensationalist, and even fallacious news items appear far less surprising when we acknowledge, along with Jacob, that the esthetic pleasure orienting poetic expression – which is dependent, precisely, on a certain distortion of truthful communication – is what the public expects from its news sources as well, if unconsciously. By identifying the texts in this collection that reference topics and discursive tropes of Belle Époque journalism (and its often indistinguishable sibling, le roman feuilleton), we find that the poet simultaneously draws on the “attractive force” of such writing, drawing his reader into its intrigue, while continually disrupting any stable referential function, through linguistic play. While Jacob is hardly an engaged artist, by laying bare the ultimately unsatisfying quick fix of headline news, reconstituting the latter as an objet d’art, he reminds us of an important truth after all: the most rewarding esthetic experiences are at once more transparent – fiction acknowledged as such – and more resistant to understanding.

2021 ◽  
Vol 55 (5) ◽  
pp. 467-474
M. A. Vashkov’yak

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 621
Yoshinori Matsuda ◽  
Teruo Nonomura ◽  
Hideyoshi Toyoda

This study analysed the mechanism of avoidance behaviour by adult Turkestan cockroaches (Shelfordella lateralis Walker) in response to a static electric field (S-EF) formed in the space between a negatively charged polyvinyl chloride-insulated iron plate (N-PIP) and a grounded metal net (G-MN). The negative surface charge supplied to the iron plate by a voltage generator caused the G-MN to polarise positively via electrostatic induction. In the S-EF, the negative charge of the N-PIP created a repulsive force that pushed free electrons in the field toward the ground via the G-MN. When insects released in the space surrounded by the S-EF inserted their antennae into the S-EF, they pulled them back reflexively and moved backward. The analysis indicated that an electric current flowed transiently toward the ground when an insect inserted its antennae into the S-EF. The insect became positively charged via this discharge and was attracted to the opposite pole (N-PIP). In response to this attractive force, the insect pulled its antennae back quickly. The positive electrification caused by the removal of free electrons from the antenna tip triggered the avoidance behaviour.

2021 ◽  
Vol 11 (1) ◽  
Hui Meng ◽  
Guiping Tang ◽  
Abby Shen ◽  
Michelle Qian ◽  
Qifeng Wei ◽  

AbstractThis investigation reveals the mystery of the cases where magnetic like poles attract each other, and unlike poles repel one another. It is identified that for two unequally sized like poles, the pole with a higher Pc (permeance coefficient) causes a localized demagnetization (LD) to the pole with a lower Pc. If the LD is large enough, the polarity of a localized area can be reversed, resulting in an attraction between these two like poles in the LD area in a small gap. Two unusual behaviors are observed: (1) an inflection point IP appears on the force vs gap curves of all the unequally sized like poles since they have different Pc. Normally, the like poles’ repelling force increases when the gap decreases, but this IP results in nonmonotonic curves, even an attractive force in a small gap; (2) for some NdFeB magnets with a low coercivity and nonlinear B–H curve in the 2nd quadrant, a repulsion can occur for these unequal sized unlike poles, after previously pairing with their like poles that left an unrecoverable LD and reversed polarity area. The relationship of the LD, the Pc ratio, and the B–H curve are also explored in this paper.

2021 ◽  
Vol 2021 (6) ◽  
Yoshihiko Abe ◽  
Yu Hamada ◽  
Koichi Yoshioka

Abstract We study the axion strings with the electroweak gauge flux in the DFSZ axion model and show that these strings, called the electroweak axion strings, can exhibit superconductivity without fermionic zeromodes. We construct three types of electroweak axion string solutions. Among them, the string with W-flux can be lightest in some parameter space, which leads to a stable superconducting cosmic string. We also show that a large electric current can flow along the string due to the Peccei-Quinn scale much higher than the electroweak scale. This large current induces a net attractive force between the axion strings with the same topological charge, which opens a novel possibility that the axion strings form Y-junctions in the early universe.

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