scholarly journals Modeling tendon-sheath mechanism with flexible configurations for robot control

Robotica ◽  
2013 ◽  
Vol 31 (7) ◽  
pp. 1131-1142 ◽  
Author(s):  
Zheng Wang ◽  
Zhenglong Sun ◽  
Soo Jay Phee
Keyword(s):  
Three Dimensional ◽  
Tendon Sheath ◽  
Time Varying ◽  
Promising Candidate ◽  
Power Sources ◽  
Tendon Elongation ◽  
Real World Applications ◽  
Tendon Tension ◽  
Fixed Path ◽  
Friction Analysis

SUMMARYSurgical and search/rescue robots often work in environments with very strict spatial constraints. The tendon-sheath mechanism is a promising candidate for driving such systems, allowing power sources and actuation motors placed outside to transmit force and energy to the robot at the distal end through the constrained environment. Having both compactness and high force capability makes it very attractive for manipulation devices. On the other hand, the friction attenuation of tendon tension is nonlinear and configuration-dependent due to tendon/sheath interactions throughout the transmission path. This is a major obstacle for the tendon-sheath mechanism to be widely adopted. Here, we focus on the friction analysis for flexible and time-varying tendon-sheath configurations: the most challenging but yet commonly encountered case for real-world applications. Existing results on fixed-path configurations are reviewed, revisited, and extended to flexible and time-varying cases. The effect of tendon length to friction attenuation is modeled. While focusing on tension transmission, tendon elongation is also discussed with the length effect applied. In the end, two-dimensional results are extended to three-dimensional tendon-sheath configurations. All propositions and theorems are validated on a dedicated experimental platform.

Visualization of microstructural change affected by mechanical stimulation in tendon healing with a novel tensionless model

Microscopy ◽  
2020 ◽  
Author(s):  
Junya Oshima ◽  
Kaoru Sasaki ◽  
Naoto Yamamoto ◽  
Tomoharu Kiyosawa ◽  
Mitsuru Sekido
Keyword(s):  
Mechanical Stimulation ◽  
Three Dimensional ◽  
Tendon Healing ◽  
Dry Weight ◽  
Tendon Sheath ◽  
Tendon Injury ◽  
Collagen Fibers ◽  
Injury Model ◽  
A Cell ◽  
Tendon Tension

Abstract Since the majority of a tendon’s dry weight is collagen fibers, tendon healing consists mainly of collagen repair and observing three-dimensional networks of collagen fibers with scanning electron microscopy (SEM) is optimal for investigating this process. In this report, a cell-maceration/SEM method was used to investigate extrasynovial tendon (unwrapped tendon in synovial tissue such as the tendon sheath) healing of an injured Achilles tendon in a rat model. In addition, since mechanical stimulation is important for tendon healing, a novel, tensionless, rat lower leg tendon injury model was established and verified by visualizing the structural change of collagen fibers under tensionless conditions by SEM. This new model was created by transplanting the leg of a rat with a tendon laceration to the back, removing mechanical stimulation. We then compared the process of tendon healing with and without tension using SEM. Under tension, collagen at the tendon stump shows axial alignment and repair that subsequently demarcates the paratenon (connective tissue on the surface of an extrasynovial tendon) border. In contrast, under tensionless conditions, the collagen remains randomly arranged. Our findings demonstrate that mechanical stimulation contributes to axial arrangement and reinforces the importance of tendon tension in wound healing.

scholarly journals Stretchable micro-scale concentrator photovoltaic module with 15.4% efficiency for three-dimensional curved surfaces

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Daisuke Sato ◽  
Taizo Masuda ◽  
Kenji Araki ◽  
Masafumi Yamaguchi ◽  
Kenichi Okumura ◽  
...  
Keyword(s):  
Concentration Ratio ◽  
Power Conversion ◽  
Three Dimensional ◽  
Thin Film Solar Cells ◽  
Photovoltaic Module ◽  
Silicon Compound ◽  
Curved Surfaces ◽  
Power Sources ◽  
Micro Scale ◽  
Module Design

AbstractStretchable photovoltaics are emerging power sources for collapsible electronics, biomedical devices, and buildings and vehicles with curved surfaces. Development of stretchable photovoltaics are crucial to achieve rapid growth of the future photovoltaic market. However, owing to their rigidity, existing thin-film solar cells based predominantly on silicon, compound semiconductors, and perovskites are difficult to apply to 3D curved surfaces, which are potential real-world candidates. Herein, we present a stretchable micro-scale concentrator photovoltaic module with a geometrical concentration ratio of 3.5×. When perfectly fitted on a 3D curved surface with a sharp curvature, the prototype module achieves an outdoor power conversion efficiency of 15.4% and the daily generated electricity yield improves to a maximum of 190% relative to a non-concentration stretchable photovoltaic module. Thus, this module design enables high areal coverage on 3D curved surfaces, while generating a higher electricity yield in a limited installation area.

scholarly journals Three-Dimensional Zirconia-Based Scaffolds for Load-Bearing Bone-Regeneration Applications: Prospects and Challenges

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3207
Author(s):  
Kumaresan Sakthiabirami ◽  
Vaiyapuri Soundharrajan ◽  
Jin-Ho Kang ◽  
Yunzhi Peter Yang ◽  
Sang-Won Park
Keyword(s):  
Bone Regeneration ◽  
Biological Activities ◽  
Three Dimensional ◽  
In Vivo Studies ◽  
High Mechanical Strength ◽  
Real World Applications ◽  
3D Fabrication ◽  
Dental Applications

The design of zirconia-based scaffolds using conventional techniques for bone-regeneration applications has been studied extensively. Similar to dental applications, the use of three-dimensional (3D) zirconia-based ceramics for bone tissue engineering (BTE) has recently attracted considerable attention because of their high mechanical strength and biocompatibility. However, techniques to fabricate zirconia-based scaffolds for bone regeneration are in a stage of infancy. Hence, the biological activities of zirconia-based ceramics for bone-regeneration applications have not been fully investigated, in contrast to the well-established calcium phosphate-based ceramics for bone-regeneration applications. This paper outlines recent research developments and challenges concerning numerous three-dimensional (3D) zirconia-based scaffolds and reviews the associated fundamental fabrication techniques, key 3D fabrication developments and practical encounters to identify the optimal 3D fabrication technique for obtaining 3D zirconia-based scaffolds suitable for real-world applications. This review mainly summarized the articles that focused on in vitro and in vivo studies along with the fundamental mechanical characterizations on the 3D zirconia-based scaffolds.

A new luminescent host material K3GdB6O12: synthesis, crystal structure and luminescent properties activated by Sm3+

2018 ◽  
Vol 233 (6) ◽  
pp. 411-419 ◽  
Author(s):  
Dan Zhao ◽  
Cong-Kui Nie ◽  
Ye Tian ◽  
Bao-Zhong Liu ◽  
Yun-Chang Fan ◽  
...  
Keyword(s):  
Solid State ◽  
Uv Light ◽  
Three Dimensional ◽  
Visual Display ◽  
Luminescent Properties ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Promising Candidate ◽  
Conventional Solid State Reaction ◽  
Host Matrix

Abstract A new borate compound K3GdB6O12 has been prepared using a high temperature flux method and structurally characterized by single crystal X-ray diffraction analysis. The structure can be described as a three-dimensional framework that is composed of [B5O10]5− groups, K+ ions and Gd3+ ions. In this structure, one crystallographic distinct site is mixed occupied by K and Gd atoms at the molar ratio of 1:1. Furthermore, Sm3+ ion was used as the activator to test primary of K3GdB6O12 to be used as a luminescent host matrix. A series of phosphors K3Gd1−xB6O12:xSm3+ were synthesized by conventional solid-state reaction. The photoluminescence properties and concentration quenching of the prepared phosphors were investigated. The results show that K3Gd1−xB6O12:xSm3+ can be efficiently excited by near-UV light. K3Gd1−xB6O12:xSm3+ might be a promising candidate for visual display and solid-state lighting as an orange emission phosphor.

Time-varying mesh stiffness calculation for gear pairs with misalignment errors in multiple degrees of freedom based on an analytical method

2021 ◽  
pp. 095440622110392
Author(s):  
Qi Wen ◽  
Qi Chen ◽  
Qungui Du ◽  
Yong Yang
Keyword(s):  
Analytical Model ◽  
Contact Line ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Single Pair ◽  
Time Varying ◽  
Mesh Stiffness ◽  
Position Change ◽  
Multiple Degrees Of Freedom ◽  
Effective Contact

Misalignment errors (MEs) in multiple degrees of freedom (multi-DOFs) at the mesh position will lead to a change in the time-varying mesh stiffness (TVMS) and then affect the dynamic behaviour of gear pairs. Therefore, a new, more rapid, three-dimensional analytical model for TVMS calculation for gear pairs with three rotational and three translational MEs is established in this paper, and a new solution method based on potential energy theory is presented. In addition, the correctness of the new model is verified by the finite element method (FEM). Moreover, the effective contact line, uneven distribution of mesh force on the contact line, and mesh position change are taken into account. Finally, the TVMS under different ME conditions is calculated with the new analytical model. The results showed that the different MEs have dissimilar effects on the TVMS, and the relationship between the ME and TVMS is nonlinear. In addition, the region of single-pair and double-pair teeth in contact would also change with ME.

Elemental analysis of lithium ion batteries

2017 ◽  
Vol 32 (10) ◽  
pp. 1833-1847 ◽  
Author(s):  
Sascha Nowak ◽  
Martin Winter
Keyword(s):  
Energy Storage ◽  
Lithium Ion Batteries ◽  
Elemental Analysis ◽  
State Of The Art ◽  
Electronic Devices ◽  
Lithium Ion ◽  
Promising Candidate ◽  
Decomposition Products ◽  
Power Sources ◽  
Large Size

Being successfully introduced into the market only 25 years ago, lithium ion batteries are already state-of-the-art power sources for portable electronic devices and the most promising candidate for energy storage in large-size batteries. Therefore, elemental analysis of lithium ion batteries (lithium ion batteries), their components and decomposition products is a fast growing topic in the literature.

Scalable submicrometer additive manufacturing

Science ◽  
2019 ◽  
Vol 366 (6461) ◽  
pp. 105-109 ◽  
Author(s):  
Sourabh K. Saha ◽  
Dien Wang ◽  
Vu H. Nguyen ◽  
Yina Chang ◽  
James S. Oakdale ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Design Space ◽  
Three Dimensional ◽  
Complex Structures ◽  
Layer By Layer ◽  
Promising Candidate ◽  
Single Digit ◽  
Cross Sectional ◽  
Two Photon ◽  
Nanoscale Features

High-throughput fabrication techniques for generating arbitrarily complex three-dimensional structures with nanoscale features are desirable across a broad range of applications. Two-photon lithography (TPL)–based submicrometer additive manufacturing is a promising candidate to fill this gap. However, the serial point-by-point writing scheme of TPL is too slow for many applications. Attempts at parallelization either do not have submicrometer resolution or cannot pattern complex structures. We overcome these difficulties by spatially and temporally focusing an ultrafast laser to implement a projection-based layer-by-layer parallelization. This increases the throughput up to three orders of magnitude and expands the geometric design space. We demonstrate this by printing, within single-digit millisecond time scales, nanowires with widths smaller than 175 nanometers over an area one million times larger than the cross-sectional area.

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