Cable Replacement Scheme for Low Tower Cable-Stayed Bridges Based on Sensitivity Analysis

Cable replacement is a key technique to solve the problems of cable corrosion and strand breakage. Cable removal causes structural changes. The choice of replacement method affects the safety of the bridge during cable replacement. A sensitivity analysis method was used to evaluate the force and deflection changes of Wohu Bridge. A reasonable method for the number and order of cable replacement was proposed; by comparing different cable removal schemes, it was revealed that the cable force and beam stress changes of the cables closest to the removed cable were the most significant. The results showed that the cable force increment of the surrounding cables was the largest when removing the longest cable. The structural impact change was small when removing the shortest cable. The maximum deflection at the top of the tower decreased with the decrease of the length of the removed cable. It was recommended to replace two cables symmetrically from the center of the tower, and the optimal replacement order was from the shortest cable to the longest cable. Furthermore, this paper also studied the influence of variable load on the cable replacement scheme, and demonstrated that the design scheme of opening part of traffic in this paper was safe and feasible

Synthesis, Modification, Characterization, and Application of MCM-41 for VOC Control.

The recently discovered mesoporous molecular sieve MCM-41 was synthesized, modified, and characterized and proposed as an alternative adsorbent for VOC control. The synthesis conditions for pure-silica and aluminosilicate MCM-41 were optimized as follows: 4.5Na2O:30SiO2:5.2C16H33(CH3)3N + :2500H2O and 7.5Na2O:30SiO2:xAl2O3:7.2C16H33(CH3)3N + :3500H2O (x n-hexane > benzene > cyclohexane

Studies of chiroptical switch

Chirality can be observed on various levels in nature and the research related to supramolecular chirality has been received increasing interest due to the tunability of the non-covalent intermolecular interactions in supramolecular systems. The recent progress in the studies of chiroptical switch is reviewed. Chiroptical switch could be fabricated not only by chiral molecules, but also by the combination of chiral and achiral molecules. In some particular cases, chiroptical switch exclusively from achiral molecules has been realized

Preparation of Fe3O4/carbon composites on the basis of cellulose microspheres and their application as anode material for lithium-ion batteries

FeO/carbon microspheres (FeO/C) were prepared by a facile hydrothermal reaction using cellulose and ferric trichloride as precursors. The resultant composite spheres have been investigated as anode materials for the lithium-ion batteries, and they show high capacity and good cycle stability (830mAhg at a current density of 0.1C up to 70 cycles), as well as enhanced rate capability. The excellent electrochemical performance is attributed to the high structural stability and high rate of ionic/electronic conduction arising from the porous character and the synergetic effect of the carbon coated FeO structure and conductive carbon coating

Cable Replacement Scheme for Low Tower Cable-Stayed Bridges Based on Sensitivity Analysis

Cable replacement is a key technique to solve the problems of cable corrosion and strand breakage. Cable removal causes structural changes. The choice of replacement method affects the safety of the bridge during cable replacement. A sensitivity analysis method was used to evaluate the force and deflection changes of Wohu Bridge. A reasonable method for the number and order of cable replacement was proposed; by comparing different cable removal schemes, it was revealed that the cable force and beam stress changes of the cables closest to the removed cable were the most significant. The results showed that the cable force increment of the surrounding cables was the largest when removing the longest cable. The structural impact change was small when removing the shortest cable. The maximum deflection at the top of the tower decreased with the decrease of the length of the removed cable. It was recommended to replace two cables symmetrically from the center of the tower, and the optimal replacement order was from the shortest cable to the longest cable. Furthermore, this paper also studied the influence of variable load on the cable replacement scheme, and demonstrated that the design scheme of opening part of traffic in this paper was safe and feasible

The influence of complexes' configuration, ligand's properties and trans-effect on the acid-catalyzed reaction mechanisms of trans-Ru(py) 4(NO2)2, trans-Ru(bpy)2(NO 2)2 and cis-Ru(bpy)2(NO2) 2

The results of the acid-catalyzed reaction under similar conditions of three dinitro complexes, trans-Ru (py)(NO), trans-Ru(bpy)(NO), and cis-Ru(bpy) (NO) (py = Pyridine, bpy = 2,2′-bipyridine) were analyzed and compared. It was found that the results depend obviously on the configuration of the complexes, structures of the ligand, and the trans-effect of the opposite ligand. The trans-effect of the ligand influences or changes the mechanism and the pathway of the acid-catalyzed reaction of the NO ligand in a Ruthenium (II) complex. If the ligand with strong trans-effect is opposite to the reactive ligand (NO), the substitution reaction of NO ligand will take place through disassociation mechanism, however, if the opposite ligand is a weak trans-effect one, such as OH, bpy, etc., the decomposition of NO ligand will occur. Whether the complexes configuration is trans or cis, the bound structure of bpy will influence the stability of the five-coordinated transition state, and also the pathway of the reaction

Improved reversible dehydrogenation properties of MgH2 by the synergetic effects of graphene oxide-based porous carbon and TiCl3

In this study, we used a combination of graphene oxide-based porous carbon (GC) and titanium chloride (TiCl) to improve the reversible dehydrogenation properties of magnesium hydride (MgH). Examining the effects of GC and TiCl on the hydrogen storage properties of MgH, the study found GC was a useful additive as confinement medium for promoting the reversible dehydrogenation of MgH. And TiCl was an efficient catalytic dopant. A series of controlled experiments were carried out to optimize the sample preparation method and the addition amount of GC and TiCl. In comparison with the neat MgH system, the MgH/GC-TiCl composite prepared under optimized conditions exhibited enhanced dehydrogenation kinetics and lower dehydrogenation temperature. A combination of phase/microstructure/chemical state analyses has been conducted to gain insight into the promoting effects of GC and TiCl on the reversible dehydrogenation of MgH. Our study found that GC was a useful scaffold material for tailoring the nanophase structure of MgH. And TiCl played an efficient catalytic effect. Therefore, the remarkably improved dehydrogenation properties of MgH should be attributed to the synergetic effects of nanoconfinement and catalysis

A facile approach for the preparation of biomorphic CuO-ZrO2 catalyst for catalytic combustion of methane

A series of novel biomorphic CuO-ZrO catalysts were prepared using a cotton bio-template and compared with conventional CuO-ZrO catalysts. The physical and chemical properties of the as-obtained catalysts were characterized by techniques including X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), H -temperature programmed reduction (H -TPR), and O -temperature programmed desorption (O -TPD). The catalytic combustion of methane was chosen as the probe reaction. The results suggested that the bio-template method prepared porous biomorphic CuO-ZrO catalysts consist of hollow microtubes. Comparing with conventional CuO-ZrO catalysts, biomorphic CuO-ZrO catalysts displayed better reducibility and oxygen mobility, stronger metal-oxides synergistic effect, appropriate particle size distribution, and lower activation energy. The crystalline state of zirconia transformed from a single crystallite phase of t-ZrO into a complex of m-ZrO and t-ZrO after introducing the bio-template. With proper CuO content (20 mol%), the biomorphic CuO-ZrO catalyst displayed preponderant properties. The compensation of surface lattice oxygen from bulk lattice oxygen was more available at high reaction temperatures