Advanced Materials Research Vols. 347-353

Abstract: The collection and utilization of urban rainwater is currently a substantial measure of ecological construction in the city which covers a variety of technologies used and reflected in the multi-dimensional overlap with the urban space. By analyzing the current trends in related technology in the world, the paper probes the organic integration of rainwater collected system with urban spatial structure and elements in a view of overall optimization. Then the paper proposes to set up the coupled design pattern for urban rainwater recycling system in a way of district division, facility grading and rainwater classification according to the characteristics of land use mode and urban planning frame.

Abstract: In electric machinery performance test, tooth harmonic time-frequency characters of first order of three-phase cage asynchronous motor are most important. The MATLAB software is used to make model and simulate the starting characteristic of asynchronous motor in this article, while the stator current signal of starting motor is de noised by wavelet transform. Through decomposition and reconstruction of wavelet transform, the amplitude of fundamental and harmonic wave in de noising stator current can be reduced, and then the tooth harmonic of first order of starting rotor is extracted. Using the excellent time-frequency analyzing characters of wavelet package transform, the tooth harmonic time-frequency curve is fitted.

Abstract: This study discussed the application of microwave-based heating for the pretreatment of biomass material, and selected Pennisetum purpureum for pretreatment. The Taguchi method was used to plan optimization experiments for pretreatment parameter levels, and measured the dynamic responses. With lower frequency of experiments, this study analyzed and determined a parameter combination in which Pennisetum purpureum can be rapidly heated to 190°C. The experimental results indicate an eight-order ARX model (Auto-Regressive eXogeneous) was representative of actual system performance, and the fit was 99.13%.

Abstract: The study on the changes of composition and content reducing sugar of wheat straw after pretreated with composite microbial system for degrading cellulose was carried out, and the experimental study on the dry anaerobic fermentation of the pretreated wheat straw was followed. The results showed for pretreated wheat straw there is a significant increase for the amount of reducing sugar, the hemicellulose content decreased 49.43%, the cellulose content also decreased a little, but the lignin content had little change. For the dry anaerobic fermentation process, the reaction is started fast, the pH values declined faster in the prophase for the pretreated straw, the mixed biogas production and the methane content have been increased over that of non-pretreated wheat straw, and the gas was produced more steadily. The accumulated gas production had been to 4810mL, which was more than the non pretreated straw, before the maximum gas production was appeared.

Abstract: Global warming has led to a lot of extreme weather phenomenon, which brought many disasters to our human being. On the context of the global climate change, the coexistence between green building and environment is especially important. In this paper, the relationship between green building and environment is discussed, and the constructing green building is a systematic project, which should be respect nature in all activities such as plan and design, construction and rebuilding with the aim to minimize the negative influence on environment as much as possible. The harmonious coexistence between green building and environment should be realized.

Abstract: A new type of cyclone combustor is designed based on the traditional pulverized coal liquid slag combustor in this paper. According to the characteristics of swirl combustion and flow, numerical simulation of pulverized coal combustion in a new cyclone combustor has carried out using Realizable k-ε equation model with swirl modified to gas phase and stochastic trajectory model under Lagrange coordinate system to particle phase. Flows and combustion characteristics under different working conditions are mainly studied by changing the angles of primary and secondary air inlets, and then structural characteristics of the combustor are analyzed. Results show that structural characteristics of the primary and secondary air have great influence on internal flow and combustion characteristics of the combustor. When the pitch angle, the rotation angle of the secondary air and the expansion angle of the primary air respectively are 20°, 51° and 60°, the combustion efficiency of the combustor can reach up to 98.1% and it is conducive to high-temperature liquid slagging. It is also helpful to prevented pulverized coal depositing and accumulating near the wall and then plugging the combusting channel during the starting stage in low temperature region.

Abstract: As a systems engineering, the primary factor of building energy-saving is determined, and the essential factor's reciprocity is researched, and then, divides the multi-essential factors into the tower system hierarchical structure for solving matter about the single index evaluation formed synthesis results of multi index. Mathematical model of tower appraisal system, with multi-index, is established based on the system theory and the analytic hierarchy method. And the evaluation model established is applied to the actual construction to carry on the multi-index comprehensive quantification evaluation to confirm model being feasibility and the validity.

Abstract: The connotation of “amenity value” was elaborated, and its role in improving agricultural production environment and operation pattern, promoting rural economic development and quality of rural residents was highlighted. On this basis, a new rural value system was established from the perspectives of agricultural functions, industrial forms and economic forms, and the concept of “rural amenities” was defined. Moreover, the development targets of “rural amenities” were analyzed, including the overall objectives and those specific ones from three aspects of production, life and ecology, and finally suggestions on the development of “rural amenities” were proposed, that is, elaborate production, elegant life and refined ecology.

Abstract: By means of researching an office building in Beijing area and making simulation analysis on the data concerning energy saving effect of building sunshade, the paper investigates the effects of different sunshade systems on indoor temperature and cooling load, and theologically selects the optimal sunshade system best suitable to Beijing area. The research shows that if a suitable inner sunshade system is applied, an energy saving effect of over 30% can reached.

Abstract: The paper is concerned with an experimental investigation of the drag reduction in turbulent channel flow over the mechanical chain. A circulating loop for the fluid flow with 0.0381 inside diameter of pipe is set up. The testing length of the system is 1.5m.Wall shear stress reduction performance has been investigated experimentally for various design geometry surfaces including a replica of bent consisting of stainless steel model scales. Attempts to optimize the net drag reduction by varying the design geometry and alignment are also discussed. The study indicated that the mechanical chain taken in water flow is capable to decrease the friction drag of a turbulent flow up to 40%. The maximum percentage was achieved in 39.37L/D at RE equal to 56733. The results show that a substantial drag reduction can be achieved by this mechanical chain in aqueous media.