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Bundle folding type III Bricard linkages
The paper presents a set of one-degree-of-freedom overconstrained linkages, which can be folded into a bundle and deployed into a polygon on a plane. The proposed mechanisms are movable Bricard octahedra of type III, characterized by the existence of two configurations where all joints are coplanar. The possible geometries of doubly-collapsible Bricard linkages are parameterized and their kinematics is analyzed. A line-intersection method is proposed to construct a bundle-folding mechanism of this type. Necessary and sufficient conditions are derived for the deployed-configuration polygon to be a square. Simulation and prototype experiment results validate the analysis and design.This research has been supported by the National Natural Science Foundation of China under Grant 51605011, 51635002(Key Program), the Fundamental Research Funds for the Central Universities (YWF-19-BJ-J-336), the State Key Laboratory of Robotics and System (HIT), and the AUTORECON project funded under the Seventh Framework Program of the European Commission (Collaborative Project NMP-FOF-2011-285189). The authors gratefully acknowledge the supporting agencies
ComposiciĂłn de lĂpidos biolĂłgicamente activos de aceites de semilla Lamiaceae
The content of glyceride oil, phospholipid, sterol and tocopherol composition of 7 species of fam. Lamiaceae seeds were investigated. 8.7-28.6 % of glyceride oil in the seeds were determined. The content of phospholipids in the oils was found to be 1.0-1.6 %. Phosphatidylcholine (35.5-63.1 %), phosphatidylinositol (19.1-30.2 %) and phosphatidyl ethanolamine (5.8-21.6 %) were the main components in the phospholipid fraction. In the sterol fraction (0.1-0.3 % total sterols in the oils) 64.8-86.3 % are in free form and 13.7-35.2 % as sterol esters. β -Sitosterol predominates in all glyceride oils (48.8-87.9 %), followed by campesterol (1.5-22.5 %) and stigmasterol (1.1-12.8 %). 6.3-649.7 mg/kg tocopherols were found, mainly α -tocopherol (48.5-99.9%).Se estudia el contenido en aceite, fosfolĂpidos, esteroles y tocoferol de semillas pertenecientes a 7 especies de la Familia Lamiaceae. Se encontraron valores comprendidos entre 8.7-28.6 % para los aceites en las semillas. El contenido en fosfolĂpidos para los aceites fue del 1.0-1.6 %. Los principales componentes de la fracciĂłn fosfolĂpido fueron: fosfatidilcolina (35.5-63.1 %), fosfatidilinositol (19.1-30.2 %) y fosfatidiletanolamina (5.8-21.6 %). En la fracciĂłn de esteroles (0.1-0.3 % de esteroles totales en las muestras de aceites), 64.8-86.3 % estaban presentes en forma libre y 13.7-35.2 % como esteres de esteroles. El β -Sitosterol es el que predomina (48.8-87.9 %), seguido de campesterol (1.5-22.5 %) y stigmasterol (1.1-12.8 %). Se encontrĂł un contenido en tocoferoles de 6.3-649.7 mg/kg, principalmente α -tocopherol (48.5-99.9 %)
Self-Motions of General 3-RPR Planar Parallel Robots
This paper studies the kinematic geometry of general 3-RPR planar parallel
robots with actuated base joints. These robots, while largely overlooked, have
simple direct kinematics and large singularity-free workspace. Furthermore,
their kinematic geometry is the same as that of a newly developed parallel
robot with SCARA-type motions. Starting from the direct and inverse kinematic
model, the expressions for the singularity loci of 3-RPR planar parallel robots
are determined. Then, the global behaviour at all singularities is
geometrically described by studying the degeneracy of the direct kinematic
model. Special cases of self-motions are then examined and the degree of
freedom gained in such special configurations is kinematically interpreted.
Finally, a practical example is discussed and experimental validations
performed on an actual robot prototype are presented
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