Applied Mechanics and Materials Vols. 556-562

Abstract: The objective of this study was to examine the influences of the type of cement and the CO₂ concentration on the carbonation progress of cement materials. Thermogravimetric analysis were used to follow mineralogical changes of standard CEM I and CEM II mortars which were submitted to an accelerated carbonation at 20% and 50% CO₂, 20°C and 65% relative humidity. The results indicated that the carbonation of portlandite is complete in the case of CEM II mortar while there is a persistence of residual portlandite in the case of CEM I mortar. In other words, the carbonation rate of CEM I mortar is slower than the one of CEM II mortar, which is not only because of its greater content of portlandite but also because of the coverage of portlandite crystals by newly formed calcite. These results allow us to conclude that the carbonation rate of cement mortars depends especially on the type of cement while the CO₂ concentration does not affect it at all.

Abstract: The objective of this study was to examine microstructural changes of cement mortar due to elevated temperature from 105 to 500°C. Changes at the meso and microscopic levels were followed by nitrogen adsorption desorption isotherms, from which the pores size distributions and specific surface areas were determined. The results show a decrease in volume of micropores and an increase in volume of mesopores which reflect clearly the shrinkage and structural transformation of the calcium silicate hydrate due to high temperature.

Abstract: Corrosion of reinforced concrete structure in the marine environment is easily happened because of the influence of chloride ion, and the corrosion in the splash zone is the most serious. Cathode protection is the most common and effective way in anticorrosion method. For simple steel structure, anticorrosion technology has been basically mature^[1].But for some complex marine engineering structures, many key technologies have not been resolved, which constraints the design and construction of such facilities. In this paper, combined the experiments and the research of the model piles of the coal wharf of Rizhao Port, the sacrificial anode protection technology has been introduced and some problems have been solved, such as the relevant operation technologies, parameter design, material selection and so on.

Abstract: In view of the the imperfection of design method of asphalt overlay on old cement under heavy-load traffic, and with the background of a successful practice of repaving improvement project in Xia Jiaying-Fen Yang expressway, this article analyzes the mechanical response of the old cement concrete road slab and the overlay, takes the influence of the void under slab on the life expectancy of asphalt overlay into account, and advances the mechanistic-empirical design process of asphalt overlay under heavy-load traffic. In comparison with Chinese standard, this method takes the influence of old concrete pavement on the reflective cracking of overlay into consideration, which ensures that there is no reflective cracking on the overlay in 3 years.

Abstract: Computed Ruiz and Penzien power spectrum model of Sutong bridge site, used the multi-point excitation response analysis method to long span bridge, the additional mass method considering the fluid effect and equivalent viscoelastic boundary method considering the soil effect. As a result, for the pile - soil - water - structure model, the internal force of main tower of Sutong bridge response decreased tendency, the peak of tower internal force response had certain phase difference effect. In addition, different structure types of the bridge by the traveling wave effect the influence degree is different, some parts of the reaction may be increased ,the other may be reduced, so analyzing response of the long span cable-stayed bridge must be consider the traveling wave, the coherent and the local effect.

Abstract: In the development process of the car, the aerodynamics has a strong impact on the automotive research and design. The initial research of aerodynamics focused on reducing air resistance and improving the car's fuel efficiency. Aerodynamic lift and side forces generated has a significant effect on the stability of cars, and even a threat to the safe driving. With the rapid development of automotive performance, the comfort and security of cars have put forward new and higher requirements, wind noise and airflow pollution generated by the aerodynamics have also emerged. How to reduce the adverse effects on the aerodynamics of cars, which is thought about by not only the people of the design, but also the users and maintenance workers in the car. In the course of vehicle maintenance, arising issues of aerodynamics have been gradually received wide attention.

Abstract: For the chase tank and large opening forms of inland waterway bulk carrier, using finite element method, the whole ship finite element model is established, the total intensity strength of the overall structure is conducted an evaluation study, the stress and strain distribution of the whole ship is obtained. The calculation methods of the entrained water quality is studied, and the entrained water quality is calculated by the method of Lewis and Todd, on this basis, the dynamic characteristics of the whole ship are calculated, the vibration characteristic of the whole ship is got, data is provided the support For the study of the important parts of inland waterway bulk carrier, and it is provided a certain reference for the design studies of inland waterway bulk carriers.

Abstract: Technical characteristics of RX240 - EST compact spinning frame agglomeration device are discussed. The tensile properties,hairiness and evenness CV and defects of the same specifications ring spinning and compact spinning yarn are tested and analyzed. Through comparison, the test shows that yarn quality of compact spinning is enhanced evidently than that of ring spinning.

Abstract: Configuration methods of weft insertion processing on air jet loom were discussed. Take GA708-280 Air Jet Loom as an example, configuration methods of weft insertion processing was analyzed, including open and close time of main nozzle and additional nozzle solenoid valve, air jet pressure of main nozzle and additional nozzle, release time of accumulator retaining pin. It is considered that jet weft time parameter of air jet loom should be set according to fabric weave and variety. Air jet pressure should be set according to method of high pressure for example 4.0×10⁵Pa to low pressure gradually.

Abstract: connecting rod parts except under larger dynamic load in the institutions, it is also connected with other parts, movement and direction, therefore, the part of the connecting rod connected with other parts on the machining accuracy is crucial. In this paper, analysis and study connecting rod machining process, through the improvement plan, ensure the accuracy of the important parts of the connecting rod parts and the connecting rod production and processing efficiency.