Force measurement of hand and fingers

Jobbágy, Ákos; Bretz, Károly

doi:10.17489/biohun/2010/1/07

Cited by 20 publications

(19 citation statements)

References 3 publications

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“…The pressure was controlled so that the rolling action did not damage the substrate. The pressure was not measured during the process, although it has been observed that middle and index fingers typically exert forces ranging between 35-50 N 26 . This was carried out when isopropanol was no longer observed on the surfaces and was carried out in order to promote embedding of the nanoparticles into the plastic.…”

Section: Synthesis Of the Carboxylate Functionalized Al2o3 Nanoparticlesmentioning

confidence: 99%

Controlling the wettability of plastic by thermally embedding coated aluminium oxide nanoparticles into the surface

Hill

Barron

Alexander

2020

Journal of Colloid and Interface Science

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Nanoparticle embedding into the surface of plastics provides an effective anchor that improves the durability of coatings formed from functionalized nanoparticles. Coatings formed from thermally embedded particles show superior wear resistance relative to coatings formed from non-embedded particles. As a consequence of this, embedded nanoparticles functionalized with hydrophilic and hydrophobic carboxylates are better suited for controlling the wettability of plastics than when the nanoparticles are deposited onto the plastic under ambient conditions. Experiments 2Carboxylate-functionalized Al2O3 nanoparticles were embedded into ethylene vinyl acetate through spray coating the particles onto the substrate during heating. Sonication was used to remove excess particles that did not become embedded into the material. Coatings formed from the embedded particles were characterized through scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive x-ray spectroscopy (EDX), and x-ray photoelectron spectroscopy (XPS).The wettability of the coatings was characterized using static and dynamic contact angle (CA) measurements to measure the apparent water contact angles, and sliding angle measurements, whilst the durability of the coatings was studied using scratch testing, tape peel tests, and abrasion tests.The build-up of fog on the substrates was also studied through exposing the surfaces to water vapour. FindingsThermal embedding of the particles into the surface of the plastic was observed to occur when the material was heated to temperatures around its melting temperature. AFM and SEM showed that plastic embedded with the nanoparticles possessed a morphology that was substantially rougher than the untreated plastic. CA measurements showed that plastic embedded with hydrophobic isostearate functionalized nanoparticles was highly hydrophobic and displayed a CA of approximately 152 o . Dynamic CA measurements and sliding angle measurements revealed that plastic embedded with the isostearate functionalized nanoparticles showed petal-like wetting behavior. Furthermore, it was observed that the CA of the plastic could be varied from highly hydrophobic to highly hydrophilic through embedding varying amounts of isostearate and hydrophilic 2-[2-(2methoxyethoxy)ethoxy]acetate functionalised Al2O3 nanoparticles into the surface of the material. Scratch testing showed that thermally embedding the nanoparticles into the plastic substantially improved their abrasion resistance, relative to when the nanoparticles are deposited onto the nonheated material. This methodology indicates that embedding nanoparticles into plastics creates 3 durable coatings that can display variable wettability. Consequently, this methodology could be useful in applications where it is desirable to keep plastics dry, such as for food packaging or medical devices.

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Section: Synthesis Of the Carboxylate Functionalized Al2o3 Nanoparticlesmentioning

confidence: 99%

Controlling the wettability of plastic by thermally embedding coated aluminium oxide nanoparticles into the surface

Hill

Barron

Alexander

2020

Journal of Colloid and Interface Science

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“…In the current study, the Taco test was simulated via a linearly increasing pressure of 200 Pa [ 44 ] applied on the external surface of the lens while the lens nodes on Y-axis were fixed. As a result, the soft lens bends, and stresses build on the lens surface.…”

Section: Methodsmentioning

confidence: 99%

Compressive behaviour of soft contact lenses and its effect on refractive power on the eye and handling off the eye

et al. 2021

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Purpose To investigate the stress-strain behaviour of 9 soft contact lens materials, that are commonly used in the market, under uniaxial compression loading. Methods Seven types of hydrogel and two types of silicone-hydrogel soft contact lens materials were hydrated in phosphate-buffered saline (PBS) solution then subjected to uniaxial compression loads. The load rate was set to 16.0 N/min starting with two consecutive initial 5.0 N loading cycles followed by three relaxation periods of 4.0 min within which there were two more 5.0 N loading cycles and eventually, a full loading cycle that stopped at a load of 49.0 N. The load and contraction data obtained experimentally were analysed to derive the stress-strain behaviour. Finite Element (FE) analysis was then utilised to evaluate the performance of soft contact lenses on the human eye and handling lenses off the eye. Results Unlike tensile tests, all tested materials showed nonlinear behaviour when tested under compression. When fitted to first-order Ogden hyperelastic model, parameter μ was found to be varying in the range 0.12 to 0.74 MPa and material parameter α was found to be varying in the range 8.2 to 20.326 among the nine tested materials. Compression modulus of elasticity was 2.2 times higher than the tensile modulus of elasticity on average. FE simulation with nonlinear Ogden constitutive model showed a limited change (8%~12%) in the optical performance when compared to other material models, however, it predicted higher stress when the lens was simulated under bending during off-eye handling. Conclusions Compression tests revealed slightly nonlinear behaviour when materials were strained under compression stress down to 15% ~ 30% of their nominal heights. Considering the physiological compression loading range of 8 mmHg, secant moduli of elasticity were 1.5% to 6.9% higher than the tension moduli of elasticity depending on the material. Tensile-based moduli of elasticity could be used in FE analysis as a step towards simulating the optical performance of soft contact lenses on-eye. However, nonlinear compression-based material models are recommended for FE analysis of soft contact lenses when lens-handling is investigated off-eye.

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“…Bretz 23 , et al has also performed some study to measure the fingers forces. Table 11 shows the results.…”

Section: Force and Torquementioning

confidence: 99%

Human Hand: Kinematics, Statics, and Dynamics

Chen

Favetto

Mousavi

et al. 2011

41st International Conference on Environmental Systems

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The human hand is an extremely complex system due to its large number of degrees of freedom (DoF) within a significantly reduced space. Moreover, it is required for most of the tasks performed by humans. That is why it is necessary to understand deeply all the characteristics of the human hand in order to develop devices interacting with it: to support it, to substitute injured parts, to help the recovery from injuries, or to enhance the performances while preserving its natural level of dexterity. The aim of this paper is to provide a complete and exhaustive summary of the kinematic, static and dynamic characteristics of the human hand as a preliminary step towards the development of hand devices such as prosthetic/robotic hands and exoskeletons. Both fields provide promising opportunities in research and space applications; the former through humanoid robotic helpers (e.g., Eurobot, Robonaut), the latter through the rising necessity to help the astronauts during Extravehicular Activity (EVA). In literature, several papers can be found analyzing kinematics, workspace, constraints and forces of the human hand 2,4 . However this information is scattered among several papers, regarding in particular the exerted forces and the dependencies of joint forces and velocities from the angular values of the same joint or the adjacent one. Direct and inverse kinematics are presented for all the fingers and the data related to maximum forces, velocities, acceleration for each joint of each finger has been collected and is presented in this work.

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Force measurement of hand and fingers

Cited by 20 publications

References 3 publications

Controlling the wettability of plastic by thermally embedding coated aluminium oxide nanoparticles into the surface

Controlling the wettability of plastic by thermally embedding coated aluminium oxide nanoparticles into the surface

Compressive behaviour of soft contact lenses and its effect on refractive power on the eye and handling off the eye

Human Hand: Kinematics, Statics, and Dynamics

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