Behavior of concrete-filled double skin steel tubular columns under eccentric compression after fire

[EN] To analysis the behavior of the mechanical properties of concrete-filled double skin steel tubular (CFDST) columns under eccentric loads after fire, the finite element analysis was used. The established FEA modeling was verified by the experimental results which has a good agreement. The FEA modeling was then used to perform the temperature field and the full-range load-deformation relations of the CFDST subject to eccentric compression after exposed to fire. The results indicate that: with the time of fire increasing, the eccentric distance increasing, the steel ratio decreasing, the yield strength decreasing and compressive strength decreasing, the bearing capacity of CFDST in circle section under eccentric loads is showing a decrease trend, and the stiffness of component decreases with the time of fire increasing, the eccentric distance increasing and the steel ratio decreasing. The ductility of CFDST became better with the time of fire increasing and the eccentric distance increasing.Liu, X.; Xu, J.; Wang, B. (2018). Behavior of concrete-filled double skin steel tubular columns under eccentric compression after fire. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 803-810. https://doi.org/10.4995/ASCCS2018.2018.7008OCS80381

Gas kinematics and star formation in the filamentary molecular cloud G47.06+0.26

We performed a multi-wavelength study toward the filamentary cloud G47.06+0.26 to investigate the gas kinematics and star formation. We present the 12CO (J=1-0), 13CO (J=1-0) and C18O (J=1-0) observations of G47.06+0.26 obtained with the Purple Mountain Observation (PMO) 13.7 m radio telescope to investigate the detailed kinematics of the filament. The 12CO (J=1-0) and 13CO (J=1-0) emission of G47.06+0.26 appear to show a filamentary structure. The filament extends about 45 arcmin (58.1 pc) along the east-west direction. The mean width is about 6.8 pc, as traced by the 13CO (J=1-0) emission. G47.06+0.26 has a linear mass density of about 361.5 Msun/pc. The external pressure (due to neighboring bubbles and H II regions) may help preventing the filament from dispersing under the effects of turbulence. From the velocity-field map, we discern a velocity gradient perpendicular to G47.06+0.26. From the Bolocam Galactic Plane Survey (BGPS) catalog, we found nine BGPS sources in G47.06+0.26, that appear to these sources have sufficient mass to form massive stars. We obtained that the clump formation efficiency (CFE) is about 18% in the filament. Four infrared bubbles were found to be located in, and adjacent to, G47.06+0.26. Particularly, infrared bubble N98 shows a cometary structure. CO molecular gas adjacent to N98 also shows a very intense emission. H II regions associated with infrared bubbles can inject the energy to surrounding gas. We calculated the kinetic energy, ionization energy, and thermal energy of two H II regions in G47.06+0.26. From the GLIMPSE I catalog, we selected some Class I sources with an age of about 100000 yr, which are clustered along the filament. The feedback from the H II regions may cause the formation of a new generation of stars in filament G47.06+0.26.Comment: 10 pages, 11 figures, accepted for publication in A&

Empirical Study on Employee Job Satisfaction in Retail Industries

Enterprises are constituted by a number of employees, Employee Satisfaction directly determine their level of enthusiasm, which affecting the basic conditions of human resources. In this area, the research about retail industries is weak. In view of this paper is to make my own explorations. So I explore the characteristics and features of investigation upon the research of Employee Satisfaction people did before. Then the evaluation criteria of Employee Satisfaction is determined. The evaluation criteria is determined quantitative by AHP, The article use the AHP and Fuzzy Comprehensive Assessment Model to find the way to assess the Employee Satisfaction effectively

Enhancing the hydrolysis of excess sludge using thermophilic Bacillus sp. Hnu under different oxygen supply conditions

A thermophilic Bacillus strain was isolated from excess sludge in the present study. The 16S rDNA analysis indicated that this strain was a Bacillus sp. and has not been reported previously (named Bacillus sp. Hnu). The aim of this paper was to investigate the enhanced efficiency of excess sludge hydrolysis by the addition of thermophilic Bacillus sp. Hnu under different oxygen supply conditions. The results indicated that higher temperature and more oxygen supply was advantageous to the volatile suspended solid removal ratio with the same effect to that of protease activity. The maximum volatile suspended solid removal ratio was achieved at 21.5 %, 42.5 %, and 54.4 % after 108 h digestion at pH 6.9 and 60°C and increased by 17.2 %, 38 %, and 45.4 % under anaerobic, microaerobic, and aerobic conditions compared with the control test, respectively. The hydrolysis rate constants for the anaerobic, microaerobic, and aerobic conditions were 3, 4.8, and 7 times (40°C) and 3.5, 9.8, and 11.8 times (50°C) and 2.7, 7.2, and 10.3 times (60°C). Hydrolysis performance indicated that the Bacillus sp. Hnu could accelerate the hydrolysis rate. The kinetic study showed that the hydrolysis of sludge with Bacillus sp. Hnu and the control test followed the first-order kinetics except at 60°C