Current Issue : January - March Volume : 2020 Issue Number : 1 Articles : 5 Articles
The increasing development of anthropomorphic artificial hands makes necessary quick metrics that analyze their\nanthropomorphism. In this study, a human grasp experiment on the most important grasp types was undertaken in order to\nobtain an Anthropomorphism Index of Mobility (AIM) for artificial hands. The AIM evaluates the topology of the whole hand,\njoints and degrees of freedom (DoFs), and the possibility to control these DoFs independently. It uses a set of weighting factors,\nobtained from analysis of human grasping, depending on the relevance of the different groups of DoFs of the hand. The\ncomputation of the index is straightforward, making it a useful tool for analyzing new artificial hands in early stages of the\ndesign process and for grading human-likeness of existing artificial hands. Thirteen artificial hands, both prosthetic and robotic,\nwere evaluated and compared using the AIM, highlighting the reasons behind their differences. The AIM was also compared\nwith other indexes in the literature with more cumbersome computation, ranking equally different artificial hands. As the index\nwas primarily proposed for prosthetic hands, normally used as nondominant hands in unilateral amputees, the grasp types\nselected for the human grasp experiment were the most relevant for the human nondominant hand to reinforce bimanual\ngrasping in activities of daily living. However, it was shown that the effect of using the grasping information from the dominant\nhand is small, indicating that the index is also valid for evaluating the artificial hand as dominant and so being valid for bilateral\namputees or robotic hands....
This study aims to present the possibility to obtain bismuth-doped nanohydroxyapatite\ncoatings on the surface of the titanium implants by using a solution-derived process according to\nan established biomimetic methodology. The bioactivity of the titanium surface was increased by\nan alkali-thermal treatment. Then, under biomimetic conditions, the titanium surface was coated\nwith a Bi-doped nanohydroxyapatite layer by using a modified supersaturated calcification solution\n(SCS) containing a bismuth salt. The apatite deposits were analyzed by scanning electron\nmicroscopy coupled with X-ray analysis (SEM-EDX), X-ray photoelectron spectroscopy (XPS), Xray\ndiffraction (XRD), and digital X-rays radiography method. The results indicate that the Bi-doped\nnanohydroxyapatite coatings on titanium surface were produced. These coatings exhibit a good\nradiopacity, thus enhancing their applications in dental and orthopedic fields. Additionally, the Bidoped\nnanohydroxyapatite coatings show significant antimicrobial activity against Escherichia coli\nand Staphylococcus aureus bacteria....
There is a high risk of serious injury to the lower limbs in a human drop landing. However, cats are able to jump from the same heights\nwithout any sign of injury, which is attributed to the excellent performance of their limbs in attenuating the impact forces. The bionic\nstudy of the falling cat landing may therefore contribute to improve the landing-shock absorbing ability of lower limbs in humans.\nHowever, the contributions of cat limb joints to energy absorption remain unknown. Accordingly, a motion capture system and\nplantar pressure measurement platform were used to measure the joint angles and vertical ground reaction forces of jumping cats,\nrespectively. Based on the inverse dynamics, the joint angular velocities, moments, powers, and work from different landing heights\nwere calculated to expound the synergistic mechanism and the dominant muscle groups of cat limb joints. The results show that\nthe buffering durations of the forelimbs exhibit no significant difference with increasing height while the hindlimbs play a greater\nrole than the forelimbs in absorbing energy when jumping from a higher platform. Furthermore, the joint angles and angular\nvelocities exhibit similar variations, indicating that a generalized motor program can be adopted to activate limb joints for different\nlanding heights. Additionally, the elbow and hip are recognized as major contributors to energy absorption during landing. This\nexperimental study can accordingly provide biological inspiration for new approaches to prevent human lower limb injuries....
Flexible and heteroatoms-doped (N, O and P) activated carbon nanofiber networks \n(ACFNs) have been successfully prepared with a mixture of polyamic acid (PAA) and \npoly(diaryloxyphosphazene) (PDPP) as a solution through electrospinning, followed by a heat post-\ntreatment. The resultant heteroatoms-doped ACFNs can be used as binder-free electrodes for high-\nperformance flexible supercapacitors (SCs) due to lightweight, three-dimensional open-pore \nstructure and good mechanical strength. Despite its surface area being lower than 130.6 m2.g^-1, the \nheteroatoms-doped ACFNs exhibited a high heteroatoms (N, O and P) content of 17.9%, resulting \nin a highly specific capacitance of 182 F.g^-1 at a current density of 1 A.g^-1 in 6 M KOH electrolyte in \na two-electrode cell and an excellent rate capability of 74.7% of its initial capacitance from 1 A.g^-1 to \n10 A.g^-1 under the mass loading of 1.5 mg.cm^-2. The electrical double-layer (EDL) capacitance and \npseudocapacitance can be easily decoupled in the heteroatoms-doped mesoporous ACFNs. SCs \ndevice based on heteroatoms-doped ACFNs exhibited a high energy density of 6.3 W.h.kg^-1 with a \npower density of 250 W.kg^-1, as well as excellent cycling stability with 88% capacitance retention \nafter 10,000 charge-discharge cycles. The excellent electrochemical performance was attributed to \nthe mesoporous structure of ACFNs and pseudocapacitive heteroatoms....
Graphene is considered a promising substance in applications related to the capture and\nreduction of the environmental impact of fluorinated gases. However, further research is still required\nto explore all related possibilities. In this work, the potential use in this context of nanofluids (NFs),\nobtained by dispersing graphene nanosheets in fluorinated ionic liquids (FILs) is investigated. As a\nstarting step, a thermal and structural characterization for this type of IoNanofluids (IoNFs) is\npresented. The highly nanostructured nature of FILs has been recently demonstrated. The presence\nof fluorinated moieties is responsible for enhancing the accommodation of solutes such as small gases.\nThe strong tendency to self-assemble forming continuous and supramolecular structures, and the\nversatility to rearrange in several conformational features allows the stabilization of nano colloidal\nsystems. It is essential to perform a comprehensive study of their structural features to understand\nthe behavior of this type of heterogeneous systems. Therefore, we present screening on the phase\nand structural behavior of these novel IoNFs to discover and develop optimized systems where FILs\nturn out to be advantageous. Thermogravimetric analysis (TGA) was employed to evaluate IoNFs\nmass losses with temperature, and their solidâ??fluid phase transitions were located using a differential\nscanning calorimeter (DSC). Their rheological properties were also determined through oscillatory\nexperiments, obtaining the viscous and loss moduli. In addition, the structural percolation transition\nwas also identified....
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