Analysis and modeling of the Z‐pin insertion in prepreg based on contact mechanism

2021 ◽  
Author(s):  
Liang Cheng ◽  
Guobiao Ji ◽  
Shaohua Fei ◽  
Jiangxiong Li ◽  
Yinglin Ke
Keyword(s):  
2020 ◽  
Author(s):  
Ganjar Kurnia ◽  
Benny Yulianto ◽  
J. Jamari ◽  
Athanasius Priharyoto Bayuseno ◽  
Mohammad Tauviqirrahman
Keyword(s):  

2013 ◽  
Vol 79 (15) ◽  
pp. 4694-4700 ◽  
Author(s):  
Michael P. Manzella ◽  
Gemma Reguera ◽  
Kazem Kashefi

ABSTRACTThe microbial reduction of Fe(III) plays an important role in the geochemistry of hydrothermal systems, yet it is poorly understood at the mechanistic level. Here we show that the obligate Fe(III)-reducing archaeonGeoglobus ahangariuses a direct-contact mechanism for the reduction of Fe(III) oxides to magnetite at 85°C. Alleviating the need to directly contact the mineral with the addition of a chelator or the electron shuttle anthraquinone-2,6-disulfonate (AQDS) stimulated Fe(III) reduction. In contrast, entrapment of the oxides within alginate beads to prevent cell contact with the electron acceptor prevented Fe(III) reduction and cell growth unless AQDS was provided. Furthermore, filtered culture supernatant fluids had no effect on Fe(III) reduction, ruling out the secretion of an endogenous mediator too large to permeate the alginate beads. Consistent with a direct contact mechanism, electron micrographs showed cells in intimate association with the Fe(III) mineral particles, which once dissolved revealed abundant curled appendages. The cells also produced several heme-containing proteins. Some of them were detected among proteins sheared from the cell's outer surface and were required for the reduction of insoluble Fe(III) oxides but not for the reduction of the soluble electron acceptor Fe(III) citrate. The results thus support a mechanism in which the cells directly attach and transfer electrons to the Fe(III) oxides using redox-active proteins exposed on the cell surface. This strategy confers onG. ahangaria competitive advantage for accessing and reducing Fe(III) oxides under the extreme physical and chemical conditions of hot ecosystems.


Author(s):  
William L. Harper ◽  
George E. Smith

Newton is best known for having invented the calculus and formulated the theory of universal gravity – the latter in his Principia, the single most important work in the transformation of natural philosophy into modern physical science. Yet he also made major discoveries in optics, and put no less effort into alchemy and theology than into mathematics and physics. Throughout his career, Newton maintained a sharp distinction between conjectural hypotheses and experimentally established results. This distinction was central to his claim that the method by which conclusions about forces were inferred from phenomena in the Principia made it ’possible to argue more securely concerning the physical species, physical causes, and physical proportions of these forces’. The law of universal gravity that he argued for in this way nevertheless provoked strong opposition, especially from such leading figures on the Continent as Huygens and Leibniz: they protested that Newton was invoking an occult power of action-at-a-distance insofar as he was offering no contact mechanism by means of which forces of gravity could act. This opposition led him to a tighter, more emphatic presentation of his methodology in the second edition of the Principia, published twenty-six years after the first. The opposition to the theory of gravity faded during the fifty to seventy-five years after his death as it fulfilled its promise on such issues as the non-spherical shape of the earth, the precession of the equinoxes, comet trajectories (including the return of ’Halley’s Comet’ in 1758), the vagaries of lunar motion and other deviations from Keplerian motion. During this period the point mass mechanics of the Principia was extended to rigid bodies and fluids by such figures as Euler, forming what we know as ’Newtonian’ mechanics.


Author(s):  
Jian Xiu Su ◽  
Xue Liang Zhang ◽  
Xi Qu Chen ◽  
Jia Xi Du ◽  
Dong Ming Guo
Keyword(s):  

Author(s):  
S. B. Chee ◽  
Ammar Al Shalabi ◽  
C. W. Chin ◽  
B. F. Yousif

This study serves to delineate the effects of material on the lifespan of a polymeric roller rubbing against a steel wire. Four materials, namely nylon, polyester, borosilicate glass and epoxy are the manipulated variables in conducting a simulation with a steel wire. A block-on-ring machine was used to conduct the tribo-experiments under dry contact condition. In concurrence with average operating conditions, the machine was set to 0.15 m/s sliding velocity, at an applied load of 10 N. Worn surfaces of the polymer were subsequently studied under optical microscopy. Frictional and wear resistance results were presented versus time for a predetermined duration. There is a strong correlation between the wear resistance and material hardness but the contrary is found with elongation at break. Findings revealed better wear resistance in epoxy due to its higher hardness. The improvement attained with reference to nylon was approximately 68%. The optical images of worn surfaces which sustained scratches and grooves implied that the contact mechanism was that of abrasion.


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