scholarly journals Mechanical Coupling Coordinates the Co-elongation of Axial and Paraxial Tissues in Avian Embryos

2020 ◽  
Vol 55 (3) ◽  
pp. 354-366.e5 ◽  
Author(s):  
Fengzhu Xiong ◽  
Wenzhe Ma ◽  
Bertrand Bénazéraf ◽  
L. Mahadevan ◽  
Olivier Pourquié
Keyword(s):  
Avian Embryos ◽  
Mechanical Coupling

scholarly journals Mechanical Coupling Coordinates the Co-elongation of Axial and Paraxial Tissues in Avian Embryos

2018 ◽  
Author(s):  
Fengzhu Xiong ◽  
Wenzhe Ma ◽  
Bertrand Bénazéraf ◽  
L. Mahadevan ◽  
Olivier Pourquié
Keyword(s):  
Cell Motility ◽  
Feedback Loop ◽  
Tissue Growth ◽  
Positive Feedback Loop ◽  
General Role ◽  
Avian Embryos ◽  
Mechanical Coupling ◽  
A Cell ◽  
Cell Intercalation

SUMMARYTissues undergoing morphogenesis impose mechanical effects on one another. How developmental programs adapt to or take advantage of these effects remains poorly explored. Here, using a combination of live imaging, modeling, and microsurgical perturbations, we show that the axial and paraxial tissues in the forming avian embryonic body coordinate their rates of elongation through mechanical interactions. First, a cell motility gradient drives paraxial presomitic mesoderm (PSM) expansion, resulting in compression of the axial neural tube and notochord; second, elongation of axial tissues driven by PSM compression and polarized cell intercalation pushes the caudal progenitor domain posteriorly; finally, the axial push drives progenitors to emigrate into the PSM to maintain tissue growth and cell motility. These interactions form an engine-like positive feedback loop, which ensures the tissue-coupling and self-sustaining characteristics of body elongation. Our results suggest a general role of inter-tissue forces in the coordination of complex morphogenesis involving distinct tissues.

A two degrees of freedom comb capacitive-type accelerometer with low cross-axis sensitivity

2019 ◽  
Vol 13 (3) ◽  
pp. 5334-5346
Author(s):  
M. N. Nguyen ◽  
L. Q. Nguyen ◽  
H. M. Chu ◽  
H. N. Vu
Keyword(s):  
Degrees Of Freedom ◽  
Proof Mass ◽  
Vibration Modes ◽  
Electrode Structure ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Fully Differential ◽  
Mode Effects ◽  
The Finite Element Analysis ◽  
Cross Axis

In this paper, we report on a SOI-based comb capacitive-type accelerometer that senses acceleration in two lateral directions. The structure of the accelerometer was designed using a proof mass connected by four folded-beam springs, which are compliant to inertial displacement causing by attached acceleration in the two lateral directions. At the same time, the folded-beam springs enabled to suppress cross-talk causing by mechanical coupling from parasitic vibration modes. The differential capacitor sense structure was employed to eliminate common mode effects. The design of gap between comb fingers was also analyzed to find an optimally sensing comb electrode structure. The design of the accelerometer was carried out using the finite element analysis. The fabrication of the device was based on SOI-micromachining. The characteristics of the accelerometer have been investigated by a fully differential capacitive bridge interface using a sub-fF switched-capacitor integrator circuit. The sensitivities of the accelerometer in the two lateral directions were determined to be 6 and 5.5 fF/g, respectively. The cross-axis sensitivities of the accelerometer were less than 5%, which shows that the accelerometer can be used for measuring precisely acceleration in the two lateral directions. The accelerometer operates linearly in the range of investigated acceleration from 0 to 4g. The proposed accelerometer is expected for low-g applications.

Failure in rocks. Hydro-mechanical coupling for erosion

2004 ◽  
Vol 8 (5-6) ◽  
pp. 709-734 ◽  
Author(s):  
Euripides Papamichos
Keyword(s):  
Mechanical Coupling

Research of operation safety and maneuverability of agricultural low-tonnage road train under critical traffic conditions

2020 ◽  
pp. 28-37
Author(s):  
Zakhid A. Godzhayev ◽  
Teymur Z. Godzhayev ◽  
Vladimir A. Korolyash ◽  
Ol’ga Yu. Solov’yeva
Keyword(s):  
Load Capacity ◽  
Research Purpose ◽  
State Technical ◽  
Safe Operation ◽  
Mechanical Coupling ◽  
Emergency Braking ◽  
Traffic Conditions ◽  
Critical Traffic ◽  
Difficult Road ◽  
Agricultural Machines

The article considers conditions for safe operation of low-tonnage road trains with overall trailers, namely universal platforms with a load capacity of up to 3 tons, capable of transporting agricultural machines, mini-factories and other equipment, as well as tourist houses. Transportation of such trailers on wheels is associated with high risks arising at small turning radii and emergency braking. (Research purpose) The research purpose is in improving the safety of operation and maneuverability of agricultural low-tonnage road trains operating in difficult road and terrain conditions of agricultural production. (Materials and methods) Authors have analyzed the results of research and experiments on the safe operation of low-tonnage road trains with trailers weighing up to 1 ton. The authors developed and tested on the basis of VIM and the Volga State Technical University a mechanical coupling device with a flexible connection that increases the handling and maneuverability of the trailer. (Results and discussion) The authors determined that the critical turning radii depending on the speed of a low-tonnage road train in different road conditions and different loading of the trailer when driving in front and rear for a conventional single-axle trailer with a load capacity of 1.5; 2; 2.5; 3 tons. It was found that the maneuverability is largely provided by the additional force in the cable, so authors recommend using a cable with a diameter of at least 9 mm. (Conclusion) Further research will make it possible to determine the critical indicators of safe operation of a low-tonnage road train with a load capacity of up to 3.5 tons: safe speed when passing critical turns, emergency braking and reversing.

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