scholarly journals Geometric conditions of a two-link-and-six muscle structure based on internal force stability

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Hiroaki Ochi ◽  
Hitoshi Kino ◽  
Kenji Tahara ◽  
Yuki Matsutani
1992 ◽  
Vol 57 (10) ◽  
pp. 2012-2020
Author(s):  
Vladimír Hejtmánek

The role of geometric factor in the course of skeletal reactions (isomerization, hydrogenolysis) of 2-methylpentane on stepped (119), (557) and reconstructed R(557) surfaces of single crystals of platinum was evaluated with computer designed models. These calculations were compared with reported experimental data. It was found by analysis of geometric conditions that there are accessible active ensembles on double step of the reconstructed R(557) surface. In addition, these active sites are unsaturated in their coordination sphere and thus catalytically effective. This finding is consistent with published data, confirming higher catalytic activity of this surface. The various pathways of Bond Shift isomerization mechanism of 2-methylpentane from the point of view of steric demands of surface intermediates on differently located ensembles are discussed, too.


2020 ◽  
Vol 118 (3) ◽  
pp. 258a
Author(s):  
Laszlo Csernoch ◽  
Mónika Gönczi ◽  
Zsolt Ráduly ◽  
László Szabó ◽  
Nóra Dobrosi ◽  
...  

2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.


Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1609
Author(s):  
Donghyun Hwang ◽  
Kyubok Ahn

An experimental study was performed to investigate the combustion instability characteristics of swirl-stabilized combustors. A premixed gas composed of ethylene and air was burned under various flow and geometric conditions. Experiments were conducted by changing the inlet mean velocity, equivalence ratio, swirler vane angle, and combustor length. Two dynamic pressure sensors, a hot-wire anemometer, and a photomultiplier tube were installed to detect the pressure oscillations, velocity perturbations, and heat release fluctuations in the inlet and combustion chambers, respectively. An ICCD camera was used to capture the time-averaged flame structure. The objective was to understand the relationship between combustion instability and the Rayleigh criterion/the flame structure. When combustion instability occurred, the pressure oscillations were in-phase with the heat release oscillations. Even if the Rayleigh criterion between the pressure and heat release oscillations was satisfied, stable combustion with low pressure fluctuations was possible. This was explained by analyzing the dynamic flow and combustion data. The root-mean-square value of the heat release fluctuations was observed to predict the combustion instability region better than that of the inlet velocity fluctuations. The bifurcation of the flame structure was a necessary condition for combustion instability in this combustor. The results shed new insight into combustion instability in swirl-stabilized combustors.


2010 ◽  
Vol 168-170 ◽  
pp. 553-558
Author(s):  
Feng Xia Li ◽  
Bu Xin

Most steel beam-column connections actually show semi-rigid deformation behavior that can contribute substantially to overall displacements of the structure and to the distribution of member forces. Steel frame structure with semi-rigid connections are becoming more and more popular due to their many advantages such as the better satisfaction with the flexible architectural design, low inclusive cost and environmental protect as well. So it is very necessary that studying the behavior of those steel frame under cyclic reversal loading. On the basics of connections experiments the experiment research on the lateral resistance system of steel frame structure has been completed. Two one-second scale, one-bay, two-story steel frames with semi-rigid connections under cyclic reversal loading. The seismic behavior of the steel frames with semi-rigid connections, including the failure pattern, occurrence order of plastic hinge, hysteretic property and energy dissipation, etc, was investigated in this paper. Some conclusions were obtained that by employing top-mounted and two web angles connections, the higher distortion occurred in the frames, and the internal force distributing of beams and columns was changed, and the ductility and the absorbs seismic energy capability of steel frames can be improved effectively.


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