Advanced Materials Research Vols. 250-253

Abstract: Genetic algorithm is a non-numerical optimization method which based on natural selection and population genetics.Using genetic algorithm to optimize the mix proportion design of high performance concrete, it takes into account the economic profitability on the foundation of satisfying the requirements of durability, strength, workability and dimensional stability of concrete, it establishes a mathematic model applying the performance of material as constraint condition, and the economic cost as optimization target.Using binary coding to represent the chromosome bit serial of individual, through selection, crossover, mutation and other genetic operator to conduct global probability search, taking the principle of “survival of the fittest”, finally achieve the best population and individual. Compare the results of optimization with the mix proportion in practice engineering case, we can reach the conclusion that Genetic Algorithm could reduce the cost, save energy, provides better use value on engineering practice.

Abstract: Dynamic wind pressures acting on structures are complicated functions of both time and space. The proper orthogonal decomposition technique (POD) is a method of detecting a new coordinate system which can most efficiently represent such random wind pressure fields to identify hidden deterministic structures. In this paper, the POD technique is applied to dynamic wind pressures on spatial structures in order to investigate the properties of these pressures and enable to understand the phenomena better. The results indicate that the POD technique can greatly reduce the amount of data that needs to be stored to re-examine the random wind pressure, which can be reconstructed by only a few dominant modes. It requires 5 modes with an accumulative proportion of 70~80% approximately. Moreover, the dominant modes can describe the spatial distributions of the fluctuating wind load effectively.

Abstract: In late-July, 2005, a series of thunderstorms dropped 10 cm of rain in a 72-h period over southwestern Sichuan province. The storms also triggered more than 17 shallow landslides along the Lama Stream, about 2.5km from Jiuxiang Town, in Hanyuan County. Almost all of the landslides were translational, occurring along the contact between colluvial and eluvial soils and the underlying bedrock (claystones, mudstones, siltstones). 1# landslide was selected in the affected area for a detailed study of the shallow landslides. The record was made of the stratigraphy, slope geometry, landslide dimensions, hydrologic conditions, and contributing factors. Both colluvial soils and underlying bedrock were sampled for laboratory investigations, which included determination of natural water content, specific gravity, natural density, Atterberg limits, coefficient of consolidation, permeability, and shear-strength parameters. Data from laboratory tests were used to perform stability analyses by the infinite-slope analysis method, with respect to varying slope angles, strength parameters, and thicknesses of saturated colluvial and eluvial soils. The results of the study indicate that the shallow landslides of Xigeda strata occurred when the colluvial soils reached 90% to 100% saturation, depending upon the slope angles. It provides a basis for taking reasonable reinforcement measures for the landslides.

Abstract: By preliminarily study and evaluation of indoor air quality issues origin, causes, influence and purpose of the research, the paper puts forward five controlling factors including: the source control and eliminate indoor pollution, air conditioning equipment optimization design, ventilation efficiency, indoor air self-purification -- green plants elimination method, architecture design should follow the principle of design of ecological environment.

Abstract: With the application of the central air conditioning system widely, it has increased fast the consumption of national energy. This paper analyzes how to control a central air-conditioning system for energy saving, mainly including control characteristics , automatic control component and the control approaches of energy saving. Energy-saving approaches consist of indoor state parameter selection control, variable-speed pump control，variable air volume system control, Storage cold control and control Optimization.

Abstract: Under the background of global warming, the concept of "low carbon" comes into being. The author puts forward the concept of low carbon community from the view of urban planning, and suggests some steps for it: The planning is carried out from Intermediate perspective, include status, location, land layout, transportation system, supporting facilities, the green space system and so on, from microscopic stratification, include water environment, energy planning, low carbon garden design and so on.

Abstract: Village as the basic prototype, most of the Chinese ancient towns have formed distinctive spatial structure in the joint action of multiple factors. Space of Chinese ancient town embodies hierarchy structure from large to small in the process of formation and development. The space system of geography, town, environment, architecture, livingmaterial produce hierarchy structure, the higher level including the lower level, the lower level reflecting the higher level, and forming system of compound spatial structure in Chinese ancient towns in the end.

Abstract: The concept of regional urban designing is put forward on the foundation of the analysis of the background of modern city designing and the current particular situation of China. This paper contends that this concept combines the place, context and ecological designing, and is founded on the characteristics of time’s development and regional natural and historical resources. This paper also brings forward that the regional urban designing will become the tendency and direction of Chinese urban designing, and that in the regional urban designing. The design and regional characteristics should be combined, in-clouding combining the design and context, and combining the design and ecology.

Abstract: This paper proposes a theoretical expression for the ultimate relationship between the crack gauge monitoring data and steel stress gauge ones in dam concrete, based on the equation for crack width of reinforced concrete member, when the cracks expanded to the crack-control steel. In addition, a practical method is developed for analyzing and determining the crack stability of dam concrete, which predicts whether a crack elongated to the crack-control steel or not by comparing the observed values to the theoretical ultimate value. The provided method is proven to be proper to evaluate the crack stability of dam, which is simple and practical.

Abstract: According to the normal method for sampling in the appendix of “The Central Air-Conditioning Ventilation System of Public Health Standard” by the ministry of health in 2006 were the HVAC on-site examined and sampled. The examined indicators include: total number of bacteria, fungus and beta Streptococcus in air supplied outlet, Legion Ella pneumophila in cooling water, the quantity of dust and microbe amounts to each square meter pipeline surface area and other sanitation indexes.