Applied Mechanics and Materials Vols. 209-211

Abstract: The selected 21 public sites for indoor air quality (IAQ) investigation located at Penghu and Kinmen Islands (Taiwan). IAQ measurements include CO2, CO, HCHO, TVOCs, bacteria, fungi, PM10, PM2.5, O3 and temperature, which were conducted during year 2010 and 2011. The results showed that the concentrations of CO, HCHO, PM10 and PM2.5 were below Taiwan EPA’s suggested IAQ threshold levels at all public sites. CO2 concentrations at hospitals and school are all exceeding category 1 threshold of 600 ppm. Besides, the levels of O3 and bacteria for hospitals and fungi for schools were all higher than the suggested IAQ threshold levels. One supermarket was found exceeding the suggested IAQ threshold levels on TVOCs and CO2. The theater was found exceeding the suggested bacteria threshold. This study discovered that the high CO2, bacteria and fungi levels occurred at various public sites. Accordingly, the regulated strategy of crowd control and air conditioning management was required for a healthy indoor environment.

Abstract: A finite element model considering the high-speed train excitation loads, track structure, vibration reduction measures, station construction, characteristics of foundation soils was established to study the problems of vibration and re-radiated noise in the underground Futian hub of Guangzhou-Shenzhen-Hongkong high-speed rail under the excitation of trains. The first 200 natural frequencies of the station are all within 40Hz, the vibration energy concentrates mainly in the second and third floors, in form of bending vibration mode; the modes of orbital plate mainly accounts for vertical vibration, and the lowest frequency is near 26Hz.When the train passes by at a speed of 200km/h, without damping rubber pads, the maximum vibration level is 57.9 dB, while with damping pads the vibration level decreases by 5~6dB. The re-radiated noise level at the surface of the structure is between 38~55.1dB;with damping measures at the orbits, the corresponding acoustic gain in upper floors is 6dB or so; some low-frequency noise excess the standard, but considering the acoustic measures in upper floors, it should be manageable. It is suggested that the train pass by at lower speed, to further reduce the re-radiated noise, to a create amore comfortable environment.

Abstract: For the purpose of utilizing of wind energy around urban buildings, an technique to gather natural wind energy by artificial energy-gathering tunnel is investigated using numerical simulation method. The configuration, performance parameters and the flow characteristics inside of the tunnel are discussed. An optimized configuration of the tunnel is obtained by numerical simulation and analysis, in which the accelerating ratio is about 2.02 and the wind power density increases about 7.24 times. The results also show that the accelerating ratio does not vary as the contraction ratio of the tunnel synchronously.

Abstract: This review summarizes the organic pollution in the indoor air of Chinese urban residences according to the order of time. Generally, Chinese researchers paid more attention to organic pollutants such as formaldehyde, the benzene series and polycyclic aromatic hydrocarbons (PAHs) in dwellings. Their concentrations were analyzed in urban residences, especially in newly decorated residences on the basis of field tests previously reported in the Chinese literature. The results indicate that there are obvious differences in the concentrations of the same kind of components in different urban residences. The concentrations in excess of the concentration limits for formaldehyde, the benzene series exist in the initial stage following completion of interior decoration. The concentrations of the different components for PAHs are obviously different in urban dwellings.

Abstract: NO is one of the key substances of air pollution. This paper presents the use of the technique of resonant enhanced multi-photon ionization (REMPI) for NO ambient detection. NO is ionized by absorbing four photons and via A2Σ intermediate resonant state when use 452.4nm laser as radiation source. A physical model concerning the ionization process is presented. It is shown that the ion signal depends on laser character and the dynamic parameters of NO. Two-photon absorption and ionization cross section about the resonant state are obtained from the ion decay curve and the model. The detection limit of this work, which can reach 1.4 ppm, is determined by measuring the variation of the ion signal with the concentration of NO.

Abstract: With the large-scale development of urban construction, the construction will lead to increasingly prominent environmental issues. The paper gives an analysis of the factors of construction which influence the environment and proposes countermeasures for environmental pollution from construction from the perspective of production process technology, green construction technology and management in order to eliminate or alleviate the environmental pollution and impacts produced during construction.

Abstract: Based on the latest national carbon dioxide emissions data released from the International Energy Agency (IEA), the carbon dioxide emissions trends of BRICS were analyzed in three aspects: the total carbon dioxide emissions, the emission intensity calculated using purchasing power parties (PPP) and per capita carbon dioxide emissions. The results show that the total carbon dioxide emissions among BRICS presented an increasing trend in different extent. On the other hand, the emission intensity calculated using PPP of BRICS showed a decreasing trend. The per capita carbon dioxide emissions of BRICS also presented an increasing trend in different extent. The Russian Federation and South Africa’s per capita carbon dioxide emissions were higher than the World’s average level, whilst those of India, Brazil and China were lower than the World’s average level, which is far less than the level of the OECD countries.

Abstract: This article discusses housing security system in our society. From the society attribute this paper gives account of the housing security problem under the different social conditions. The article also argues the critical roles of housing security system under the modern society. The paper also reviews the progress from welfare or public room to indemnificatory or affordable housing in China, and many essential characteristics including general and individual character are well analyzed.

Abstract: This study aims to analyze the effects and impacts of the main factors of urban built-up area expansion in Hangzhou, which can provide a reference to urban policy makers and urban planners on how to make a rational plan to develop the sustainable city. The study mapped Hangzhou urban built-up areas in different periods based multispectral scanner (MSS), thematic mapper (TM) and Enhanced Thematic Mapper-plus (ETM+). according the grey correlational degree analysis between urban built-up area expansion and the main social economic factors in Hangzhou, the results show that the sequence of the factors is non-agricultural population, on-campus college students, the industrial output value, GDP and the total investment in fixed assets, and it indicate that non-agricultural population play a key role to control the scale of urban space ，and the increasing number of on-campus college students promote Hangzhou urbanization.

Abstract: Faced with two big stresses of energy shortage and environmental pollutants, China should improve its energy utilization efficiency. Based on the data of China Statistical Yearbook and China Environmental Statistics Yearbook, the pollutants discharge and energy utilization efficiency, including technical efficiency (TE), pure technical efficiency (PTE), scale efficiency (SE) and returns to scale (RTS) of China’s industry and its sub-sectors were analyzed by constant returns to scale model (CRS) and variable returns to scale model (VRS) of non-parametric data envelopment analysis (DEA) method. Results showed that: (1) The RTS of China's total industrial environmental efficiency and energy utilization efficiency were all in "irs" state, indicating that it was beneficial to expand the entire industrial scale. (2) The TE of total industrial energy utilization efficiency was about 0.80, the minimum TE was 0.018 of production and distribution of gas sector. (3) The total industrial environmental efficiency was about 0.77, the two sectors with high pollutants discharges were mining of other ores and manufacture of paper and paper products, and TE were 0.065 and 0.067, respectively. Mostly industrial sub-sectors should improve their technologies and adjust its scales except for extraction of petroleum and natural gas, manufacture of tobacco, printing, reproduction of recording media and so on. (4) Mining of other ores, manufacture of tobacco, manufacture of communication equipment, computers and other electronic equipment, manufacture of measuring, instruments and machinery for cultural activity and office work and production and distribution of water were in high energy utilization efficiency while in low environmental efficiency and steady RTS. So these sectors should improve the technologies to achieve DEA effective. (5) Scale expanding, technology advancement, energy use pattern improvement and industry structure adjustment were suggested for energy-saving industry according to the TE, PTE, SE and RTS.