Applied Mechanics and Materials Vols. 501-504

Abstract: Combined with the project which a grain silo need be transformed, a new type of silo is put forward. The silo system consists of supporting columns, the silo body and latticed shell roof structure. In view of the force is different between silo shell roof and conventional roof, and silo shell roof prones to buckling failure. The linear and nonlinear buckling analysis was carried out for latticed shell with a diameter of 20m, the results show that the buckling loads obtained by linear buckling analysis is greater than that obtained by nonlinear buckling analysis, and nonlinear analysis is more secure for structures. Through the comparison the rationality and stability of reticulated shell design are verified, finally construction measures of this system are given, and these can provide references for design and construction of similar engineering.

Abstract: Features of thermal parameters measuring for various types of masonry and for single stones are presented. Problems are shown that appear during testing of some types of masonry. Tasks are posed for improving of test methods.

Abstract: Building rubbish has already become a staggering problem in waste products management and environmental pollution.According to the characteristic of building rubbish, the regenerated resources and reclamation management of the building rubbish in developed countries is introduced in this paper. And the corresponding counter measures for building rubbish reclamation management are put forward.

Abstract: One of the basic principles of energy efficient buildings in accordance with sustainable development is perfectly airtight building envelope. Oversized heat loss through the building envelope leakage adversely affects the energy balance of buildings. The paper provides diagnostic of the recent developments in airtightness of buildings using qualitative method. The aim of this paper is to draw conclusions - dependences, definitions of weak and strong points of the process, their causes and consequences.

Abstract: Courtyards are now used in many new buildings in China for taking advantage of better natural ventilation and thus improving the microclimate. However, when the building is equipped with a central air-conditioning (AC) system for space heating in winter, the warm air infiltration from the heated rooms enters into the courtyard and leads to changes in the natural ventilation characteristics in the courtyard. In the present study, the air environment and energy performance of a courtyard style office building in Shanghai were monitored in winter. The internal and external environmental parameters such as air temperature, CO2 and particle concentrations were measured simultaneously and continuously when the building was heated or was not in use. The results show that when there is no apparent pollutant source in the courtyard, a better microenvironment can be established and the air quality in the space is almost the same as the ambient air, because its natural ventilation is enhanced by the warm air infiltration from the heated rooms. Compared to a building without a courtyard, the building envelope heat loss can be reduced by 20% or 11% in winter for buildings with or without a corridor facing the courtyard enclosed by glass windows, respectively, due to the warm air infiltration which increases the air temperature in the courtyard.

Abstract: This article discussed the factors that affect the lifetime of catalyst. For the lifetime of catalyst about catalytic combustion burner III 1100 hours were obtained. The local surface temperatures of monolith, the gas temperature inside channels and pollutant concentrations were measured. The ageing of catalyst to the change of local surface temperatures and gas temperature was approached and its affecting factors were analysed. This will improve the working conditions of catalytic combustion burner in future, and prolong its lifetime of catalyst.

Abstract: Taking the radiant cooling combined with wall-attached-jet air-conditioning system as the subject in a laboratory of Jiangsu university, an experimental study was carried out on pre-dehumidifying period, stable operation period and system shutdown period, along with analysis. The objective is to analyze the pre-dehumidification of the system, indoor air temperature and humidification change, vertical temperature profile and condensation sensitivity. The results show that the hybrid air-conditioning can provide high thermal comfort and avoid condensation effectively, which shows the better performance compared to the system of radiant cooling combined with displacement ventilation to some extent.

Abstract: Based on the structural features of the cold-formed thin-walled steel structure residence, a green environmentally friendly double-layer air circulation system with the respiratory function has been developed to explore the impact mechanism of the system on indoor thermal environment. Various index properties and influencing factors including velocity field, temperature field, PPD-PMV distribution etc, from the various components of the air circulation system during operation by using 3D numerical simulation function of Fluent and Airpak, have been examined, whereby to evaluate the indoor airflow and air quality. Research shows that the buffer layer of air can provide good air source for both the inner and outer air layer; the outer layer of air can dynamically isolate indoor and outdoor heat by taking advantage of stack effect; under the premise of low energy consumption, the utilization of the entire double air circulation system can improve the indoor thermal environment as well as provide 24-hour fresh air for the indoor occupants, so that the purpose of energy saving and environmental protection could be achieved.

Abstract: In this paper, the existing methods of ventilation system and smoke control system that used in the underground car parks have been briefly reviewed. Compared to other methods, the impulse ventilation system (IVS) has a lot of advantages, and has great development space in the current. The progresses of research on IVS are summarized, and some key problems (like flow field characteristics, installing parameters of induced fan, influence of space structure to smoke and so on) that have a guiding effect on relevant standard specification are discussed. Some basic principles that followed in the process of layout of IVS are analyzed.

Abstract: Analyzing the characteristics of the gas diffusion in soil porous media, and using proper coefficient to correct the calculation model of aerial pipeline leakage,with which to establish the diffusion model of buried gas pipeline. Combined with the mass conservation equation, fick diffusion equation and relative diffusion coefficient equation to build three-dimensional steady-state diffusion model. Then using dimensionless analysis method to calculate the diffusion equation. Through example analysis to research gas concentration fluctuations with the change of buried depth, aperture size, soil properties. Get the rule of small aperture leakage under the condition of different soil properties and rainfall, and it can be used as reference basis for scientific positioning and adopting emergency measures.