Abstract: The urban ecological territory model uses traditional ecological evaluation methods, such as ecological carrying capacity and ecological footprint, to create a new urban ecological model that uses a quantified spatial structure. This new model allows for the quantitative analysis of indicators such as ecological efficiency, quality, security, and fairness. The paper presents an example application of the model through a comparative analysis of two cities. Analyses using the new model can be used to guide urban development policy decisions.
Abstract: In order to ensure the high-speed railway train running safety and stabilization, the subgrade should keep adequate strength, rigidity and long-term stabilization under the repeated train load. When the subgrade soil is poor, we can treat it with cement. Whether the performance of cement-treated soil can meet the demand of high-speed railway, so the dynamic triaxial test of cement-treated soil is studied in this paper. The dynamic performance of cement-treated soil under repeated train load is analyzed. The variation and influence factors of critical dynamic stress, accumulated plastic strain, elastic strain and resilient module of cement-treated soil are studied.When the dynamical stress more than the critical dynamical stress, the cumulate plastic strain and the elastic strain will rapidly increase with the increase of the loading time of the dynamical stress. The resilience modulus will decrease along with the increase of the dynamical stress. When the dynamical stress less than the he critical dynamical stress, the elastic strain and the resilience modulus remain constant with the increase of the loading time of the dynamical stress. And the elastic strain and the resilience modulus linearly increase with the increase of the dynamical stress.
Abstract: The mechanism of fluid flow and heat transfer in the heat exchangers was investigated in this paper. Using R22 as the working fluid, the steady distributed parameter models of condenser and evaporator in a residential split air-conditioner were established based on thermophysical laws such as mass, momentum and energy conservation equations. The regions of two-phase fluid and superheated gas in evaporator and the regions of superheated gas, two-phase fluid and subcooled liquid in condenser were respectively simulated under designed conditions of air-conditioning system. Based on the calculated results, the flow and heat transfer performances of heat exchangers were analyzed. The results show that the two-phase fluid regions in both evaporator and condenser have great influence on the fluid flow and heat transfer performances in it.
Abstract: The public buildings and facilities investigated in this paper have disaster prevention signs, but they have the defects such as non-uniform, having gaps and unsystematic. The human subjective initiative of disaster prevention signs lays in the sign cognition which is influenced by many factors. In this paper, comprehensive investigation has been taken, and the relevance between disaster and sign cognition has been analyzed. A new perspective that cognizance regions are classified as risk, transitional and safe is proposed. Besides, the ways of setting up signs according to different regions have been researched. These contributes to the cognition of disaster prevention signs.
Abstract: In this paper, the dynamic responses of an arch dam in the case of normal water level and operating low water level were simulated by using additional mass model and incompressible finite element model for reservoir respectively. The results showed that the reservoir models have a great impact on dynamic response of arch dams. The maximum principle tensile stress using incompressible finite element model of fluid is less than that using additional mass model. With the depth of the reservoir water increasing, the hydrodynamic pressure acting ton the dam surface caused by earthquake force increased and the dynamic responses of dam also increased.
Abstract: The three-dimensional model of slop in numerical calculation is established. And high precision eight-node hexahedron element is used to build the finite element grid of slip layer. The slip layer material is simulated by an ideal elastic-plastic model based on the Mohr-Coulomb Criterion. Three-dimensional stress state and slide direction of the slip layer zone is obtained by numerical computation. So, based on the analysis of the three-dimensional stress state of the slip layer zone, in this article, the author defines the point safety factor as the ratio of the shear strength of the slip zone to the shear stress parallel to the sliding direction, and defines the safety factor of the landslide as the average of the zone point safety factor with its zone as weight number. The sliding mechanism is studied through zone point safety factor, and stability of landslide can be evaluated through the safety factor. Sample case shows that the calculated result is in accordance with the actual case.
Abstract: Based on the Yuwangbian high loess slope, which is located in Xi'an Yanta District, the basic principle of Monte-Carlo method is presented. By means of geotechnical engineering and geotechnical environment emulation software Geostudio-slope/w and based on Morgenstern-Price slope stability analysis method, the reliability and stability of the slope are analyzed under different kinds of working condition. The stability factor, reliability index and failure probability under the corresponding working conditions has been obtained. The results coincide with the actual condition, which makes the Geostudio software combine with the Monte-Carlo method and provides reference for the reliability analysis of loess slope.
Abstract: As the lake water of Yuyuantan Park of Beijing has became micro-polluted water after the cycles of social landscape and the micro-polluted water run into the Kunyu River, the research adopts a method of manual simulation to treatment the micro-polluted water with a new-type of compound pattern we call landscape-designed ecological barrier which consists of ecological pond and constructed wetland . In order to weak the adverse effects of micro-polluted water on natural water, this new-type of compound pattern forms a landscape-designed ecological barrier. After 5 months experiment, results show that the landscape-designed ecological barrier has a better removal of pollutants. The removal rates of COD, TN and TP respectively reached 65.2% ~ 73.6%, 62.5% ~ 66.0% and 70.0% ~ 80.0%. And the effluent quality can reach III - IV water-quality of environmental quality standards for surface water(GB3838-2002). In Autumn, the concentration of CODCr, TN and TP in effluent sustain at IV water-quality of environmental quality standards for surface water(GB3838-2002), and at the same time create artificial landscape water with environmental aesthetic and ornamental value, bring the benefit of water resources as well as positive ecological environment effects into full play synthetically.
Abstract: This paper presented the results of assessment pollutant load such as nutrient and phosphorus on Brantas River basin Indonesia. A Soil and Water Assessment Tool (SWAT) was choose to applied in this study due to successful for simulate the effect land used management from large watershed in many countries. Stream flow and sediment yield were calibrated for the 1991-2003 period and validated for the 2004-2006 period. The resulting statistical goodness-of-fit was evaluated with the Nash-Sutcliffe coefficient NS = 0.38 and R2 of the one-to-one line for monthly stream flow was 0.725. Results showed that annual average nutrient loads such as organic N, organic P, nitrate, sediment P increased in trend from 1991 to 2006. Simulated results showed that average annual nutrient load was 60.88 kg N/ha/yr for organic N, 11.64 kg N/ha/yr for Nitrate, 0.08 kg P/ha/yr for organic P and 0.25 kg P/ha/yr for soluble P, respectively. The most dominant type of land use contributing to increased nutrient load in rivers was the rice field. The water quality of Brantas River did not meet class II in term of nutrient parameters based on local water quality standard.
Abstract: For most of previous study on electron beam drilling (E.B) or laser beam drilling (L.B), the evaporating phenomena was assumed to be a minor parameter and could be neglected. In fact, the assumption usually leads to the overestimation of drilling efficiency and causes a significant deviation from experiment result. To improve this defect, a critical flow theory, based on the reacting pressure downward into the melting layer, is first introduced in this study; which not only successfully separates the evaporating model to convective model, but the critical transition of drilling characteristic will be also accessed. Examine the melting cavity of copper drilling conducted in E.B process, the evaporating phenomena responsible for drilled cavity had been verified to be as a prior parameter as the incident energy density is below 6×1010 w/m2. When compared with the experiment data made by Allmen , proposed theory shows an excellent agreement for copper drilling and their relative errors are no more than 30%.