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In recent decades, with the growth of population and the acceleration of urbanization in China, cultivated land resources have become increasingly scarce, and cultivated land embodied in trade has become more and more important to areas with insufficient arable land. The measurement of embodied cultivated land is critical to explore the land use profile and understand the social and environmental issues related to land. However, few studies have explored the embodied cultivated land change and its socio-economic driving forces. Therefore, this study tracks the cultivated land embodied in products and serves traded between 30 provinces and 8 regions in China, adopting a multi-regional input-output model. We also identify the determinants of the changes in embodied cultivated land use through the structural decomposition analysis (SDA). Here we found that more than 80% of total cultivated land consumption in Shanghai, Tianjin, and Beijing is satisfied by other provinces, indicating that the more economically developed a province is, the less self-sufficient it will be with respect to the land required to support its consumption. The average proportion of embodied cultivated land among Chinese provinces is shown to have decreased from 41.39% in 2007 to 35.35% in 2012, indicating that dependence on cultivated land among Chinese provinces increased over this period. The results also highlight the fact that the most affluent regions in China, including the South Coast, Central Coast, and Beijing–Tianjin, have the highest imports of cultivated land embodied in products from the underdeveloped central and western regions. Further, our SDA results reveal that in most provinces, changes in embodied cultivated land can be attributed to the factors of cultivated land-use intensity and consumption volume. This paper helps determine where the responsibility for land consumption lies and provides data support for the construction of a land governance system, which helps to achieve environmental equity in the context of regional trade. • The embodied cultivated land-use change and its drivers were explored through MRIO and SDA. • More than 80% of cultivated land consumption in Shanghai, Tianjin, and Beijing is satisfied by other provinces. • The average proportion of embodied cultivated land among Chinese provinces decreased by 6.02%. • The changes in embodied cultivated land is mainly attributed to changes in land-use intensity and consumption volume. [ABSTRACT FROM AUTHOR]

Rapid urbanisation has resulted in a series of urban sustainability challenges. Green infrastructure, with its associated emphasis on multifunctionality, has been advocated by scholars and practitioners alike as a key part of responses seeking the transition to sustainable urban environments. In support of this, a number of assessment frameworks have emerged which seek to assess green infrastructure needs and opportunities. Increasingly it has been recognised that such frameworks will need to provide a greater degree of emphasis upon social and perceptual values and focus more actively upon the neighbourhood scale. This need is particularly apparent within a Chinese context. Research on the role of green infrastructure within China, however, has tended to prioritise comprehensive city-wide or regional assessments. To date, there have been very few studies at the neighbourhood level which have attempted to consider both objective and subjective GI characteristics and how barriers might be mediated. In response, this paper seeks to develop an improved understanding of neighbourhood level GI needs. Through the use of both objective and subjective indicators linked to levels of green infrastructure provision and satisfaction, we outline how strategic responses might be developed to different neighbourhood contexts to aid a more adaptive and spatially sensitive approach to sustainable urbanisation. [ABSTRACT FROM AUTHOR]

Abstract: This paper analyses the duration of housing project sales in the city of Beijing, China. In the housing market, new properties sometimes experience delays before they are sold. Such delays reflect the preferences of buyers with regard to the characteristics of the dwelling. Therefore, it is important for managerial purposes to identify the causes of delays in the sales of housing projects. A survival model with heterogeneity is adopted in the present research. The principal finding of this study is that delays are largely explained by the characteristics and the location of the housing project. Policy implications of the research findings, particularly those related to means of reducing the delays, are discussed. [Copyright &y& Elsevier]

Abstract: The identification of the relationships between different landscape services is important in social–ecological complex systems, especially in areas with intensive human activities. In this paper, Beijing and its peripheral regions are taken as a case study to calculate and map the intensities of five classic landscape services including material production, carbon storage, soil retention, habitat conservation, and population support based on grid maps. Overlap and correlation analyses were used to identify multiple service hotspots and the relationships between landscape services. The results show that (1) landscape services have spatial heterogeneity: high-intensity area of material production and population support is on the southeast plains of this region and high-intensity area of soil retention and habitat conservation is on the northwest; (2) approximately 96.03% of the region can provide at least one type of landscape services, whereas approximately three-quarters of the area provide multiple services, with the multiple service hotspots surrounding Beijing and Tianjin; (3) correlations exist between all pairs of landscape services, but strong correlations (correlation coefficient >0.5 or <−0.5) exist between four pairs, which are soil retention and habitat conservation (0.672), soil retention and population support (−0.613), habitat conservation and population support (−0.540), and material production and population support (0.529); (4) the services can be divided into two trade-off service bundles: the “natural” bundle, which contains carbon storage, soil retention, and habitat conservation, and the “artificial” bundle, which contains material production and population support. Only 4.19% of the area in this region contains these service bundles simultaneously. Finally, an improved understanding of the relationships between services was illustrated, and the importance of such services was highlighted for decision-makers and stakeholders. [Copyright &y& Elsevier]

Abstract: This paper aims to describe the joint choice of residential location, travel mode, and departure time. First, based on random utility maximization theory, the Cross-Nested Logit model and traditional NL models are formulated respectively. House price, travel time, travel cost, and factors depicting the individual socio-economic characteristics are defined as exogenous variables, and the model choice sets are the combination of residential location subset, departure time subset, and travel mode choice subset. Second, using Beijing traffic survey data of 2005, the model parameters are estimated, and the direct and cross elasticity are calculated to analyze the change of alternatives probability brought by factors variation. Estimation results show the Cross-Nested Logit model outperforms the three kinds of NL model. It is also found by estimation results that decision makers will change first their departure times, then their travel modes, and finally their residential locations, when exogenous variables alter. Moreover, elasticity analysis results suggest that, for long-distance commuting, it is difficult to decrease car travels even if additional charges are imposed on car users. The effect on choice probability by variations in travel time of other travel mode can be considered as negligible for alternatives within 5km commuting distance, and this effect are greatest for alternatives between 10 and 20km commuting distance. These findings have important implications for transport demand management and residence planning. [Copyright &y& Elsevier]

Abstract: Although the scale and speed of China’s urban and economic transition is well acknowledged, a detailed account of the transformation of a single city’s development in this context is quite rare. This paper provides an insight into the recent dynamics of China’s capital city, Beijing. In the early 1980s, China’s transition process from a planned to a market economy started to deeply affect the urban economy of Beijing, so much so that the city is on its way to become one of the world’s leading cities. This article focuses on this development by looking at Beijing’s institutional context and its economic-spatial dynamics over the past 30years. Economic Clusters (ECs) are also discussed because they have contributed significantly to Beijing’s rapid growth and change. The city’s development is however under increasing pressures of ecological deterioration, limited water resources, high living costs and uncertainties regarding the future urban policy orientation of the city region. These current challenges and responses in planning are assessed and discussed. [Copyright &y& Elsevier]

Abstract: Hydraulic Control Rod Drive Technology (HCRDT) is a newly invented patent of the Institute of Nuclear and New Energy Technology of Tsinghua University which owns HCRDT’s independent intellectual property rights while the integrated valve made up of three direct action solenoid valves is the key part of this technology. Therefore, the performance of the solenoid valve affects the integrated valve and the HCRDT directly. In this paper, firstly, we improve particle swarm optimization (PSO) by Cloud Model and the improved PSO is called CloudPSO. Then, the method is used to optimize the parameters of the direct action solenoid valve. At last, the results are verified by the experiments. The results prove that the method is feasible and accurate to obtain the key parameters of the solenoid valve in order to achieve the biggest electromagnetic force. Besides, the algorithm is analyzed. [Copyright &y& Elsevier]

Abstract: Since the late 1970s, transitions in socioeconomic status and new governmental policies have led to drastic changes in agricultural land use types and farm management practices across rural China, such as an increase in the area of land cultivated for cash–crops (e.g. vegetables and orchards) and intensive fertilization and irrigation of this land. How this more intensive management and land use for the more profitable cash crops affects soil nutrients is of great concern for carbon, soil and water quality management. In this paper, we attempted to assess the influence of cash crop ecosystems on soil nutrients in the catchment upstream of the Guanting Reservoir, in the Beijing municipality, North China plain. Soil nutrients in cash crop (orchard and vegetable) ecosystems with between 8 and 20years of intensive management history were compared with traditional agro-ecosystem management patterns (corn and soybean). Results showed that soil organic carbon (SOC) had improved, and total nitrogen (N), and available phosphorus (P) concentrations had marginally increased under intensive management practices in the vegetable and orchard ecosystems in the last 25years. The increases in SOC and total P densities at the 100cm soil depth in orchard, vegetable and irrigated corn systems were greater than those in the rain fed corn and soybean systems. Soil available P and electrical conductivity (EC) were highest in the vegetable lands. However, no significant changes were found between the soil physical properties (i.e. bulk density, clay content and water stable aggregate content) of the traditional and cash-cropping systems. Multi regression analysis showed that manure and mineral fertilizer contributed significantly to the increase in soil nutrients. Intensively managed orchards are a better option for improving soil quality and SOC sequestration. However, the risks of nonpoint source pollution from, and soil salinization in, the land used for vegetable cultivation should be considered in the future. [Copyright &y& Elsevier]

Abstract: The focus of the current study is the wind loads on a 10.5 m × 9.0 m heliostat with a column height of 6.4 m, located in Beijing, PR China. This paper presents selected results of wind tunnel measurements of wind pressures on the heliostat. Wind pressure distributions are presented for typical configurations. Fluctuating wind pressure characteristics are analyzed, including skewness and kurtosis coefficients, fluctuating pressure spectra and probability density functions. [Copyright &y& Elsevier]

Abstract: Taking Beijing as a case study, this paper analyses new trends in peri-urbanisation and the city’s planning responses after 2000 in China. The results of the analysis show that the percentage of temporary migrant residents continues to grow in the peri-urban region and the social inequalities in relation to quality of life between local people and migrants have increased there. In particular, there is a concentration of thousands of young and well-educated migrants in the peri-urban region, resulting in a new kind of urban slum. Sprawling development still dominates Beijing’s fringe. New planning policies related to an urban–rural integration strategy have played a positive role in improving living conditions in rural areas and reducing the social and economic gaps between urban and rural areas in the peri-urban region. However, planning in the peri-urban region is still facing new challenges due to vertically and horizontally fragmented management, growing market forces, and social discrimination caused by the remnants of the hukou mechanism. This suggests that it will not be easy to achieve the planning goal of urban–rural integration and harmony society unless further actions are taken to enhance political capacity of planning system in Beijing. The capacity-building of planning should be facilitated if institutional innovations can be made in arrangements of power, rights, public resources, accountability, and legitimacy in the planning system. [Copyright &y& Elsevier]

Abstract: This paper contributes to the study of planning for low-carbon cities by providing empirical evidence on the relationship between planning parameters (i.e., density, land use mix, accessibility to public transportation and jobs-housing balance) and household carbon emission in Beijing, China. Five neighborhoods representing different levels of carbon emission are selected using a household survey dataset that includes 1227 sample households; these neighborhoods are analyzed using the survey dataset together with land use data provided by the Beijing Municipal Urban Planning Commission. Findings confirm that higher population density, mixed land-use patterns, better accessibility to public transportation, and job-housing balance are important planning parameters that reduce household carbon emission in Beijing. This research provides the first empirical evidence from a large Asian city that can assist planners and policy makers in estimating the impact that planning principles can have on reducing household carbon emission. [Copyright &y& Elsevier]

Abstract: This paper aims to study the vehicular emissions trends in the Beijing–Tianjin–Hebei (BTH) region, located in northern China. The multiyear emission inventories of NO X , CO, VOC and PM10 from road vehicles in the period 1999–2010 were developed by the COPERT IV model. Results show that vehicular emissions of CO and VOC have decreased by annual average change rates (AACR) of −3.1% to −5.2% and −4.4% to −6.9% in the study area, respectively. However, due to the rapid development of freight traffic, emissions of NO X and PM10 have kept increasing in Tianjin and Hebei. Based on the vehicular emission inventories, trends of emission levels for vehicles with different standards, as well as the overall effects of implementing vehicular emission mitigation strategies were assessed. It is suggested that passenger cars (PC) with Euro 0 and Euro I standards, which were at higher emission level in the PC fleet, should be gradually eliminated. Although the increasing rates (IR) of emissions from PC were lower than those of the PC population, the sharp growth of PC population in recent years contributed to a remarkable increase of emissions, weakening the overall mitigation effect. Total vehicle population capacity and other mitigation measures should be studied in China in order to develop new and more effective vehicular emission control strategies. [Copyright &y& Elsevier]

Abstract: Permit or license plate quotas are highly effective albeit controversial policy tools for managing growth in the vehicle population and thereby, adverse traffic congestion. A judicious distribution of the scarce permits that targets the dual objectives of price efficiency and social diversity in vehicle ownership can however mitigate the controversy. This paper scrutinizes the attainment levels of these two objectives within Singapore’s multi-categorical Vehicle Quota System in two time periods (1991–1998 and 2002–2011) which differ in the number of permit allocation categories, the auction format used (sealed versus open bids) and in the frequency of distribution (monthly versus semimonthly). The lessons derived are contrasted to the other two jurisdictions which have also implemented quotas on their vehicle registrations namely, Shanghai and Beijing. [Copyright &y& Elsevier]

Abstract: In order to further study the realization of carbon intensity target, find the key influencing factors of CO2 emissions, and explore the path of developing low-carbon economy, this paper empirically studied the influences of urbanization level, economic level, industry proportion, tertiary industry proportion, energy intensity and R&D output on CO2 emissions in Beijing using improved STIRPAT (stochastic impacts by regression on population, affluence and technology) model. The model is examined using partial least square regression. Results show that urbanization level, economic level and industry proportion positively influence the CO2 emissions, while tertiary industry proportion, energy intensity and R&D output negatively do. Urbanization level is the main driving factor of CO2 emissions, and tertiary industry proportion is the main inhibiting factor. In addition, along with the growth of per capita GDP, the increase of CO2 emissions does not follow the Environmental Kuznets Curve model. Based on these empirical findings and the specific circumstances of Beijing, we provide some policy recommendations on how to reduce carbon intensity. Beijing should pay more attention to tertiary industry and residential energy consumption for carbon emission reduction. It is necessary to establish a comprehensive evaluation index of social development. Investing more capital on carbon emission reduction science and technology, and promoting R&D output is also an efficient way to reduce CO2 emissions. [Copyright &y& Elsevier]

Summary: Some commentators have claimed that there is a growing Beijing Consensus among emerging and developing economies concerning the merits of China’s economic policies. Within an analytical framework provided by the well known international policy trilemma, this paper investigates the empirical evidence concerning this claim with specific reference to the adoption of international macroeconomic policies. We find that there are substantial differences between what China does and what is done in other emerging and developing economies. While we discover some regional and inter-temporal variations, there seems to be little or no support for the existence of a Beijing Consensus. [ABSTRACT FROM AUTHOR]

Abstract: An identification of economic clusters and analysing their changing spatial patterns is important for understanding urban economic space dynamics. Previous studies, however, suffer from limitations as a consequence of using fixed geographically areas and not combining functional and spatial dynamics. The paper presents an approach, based on local spatial statistics and the case of Beijing to understand the spatial clustering of industries that are functionally interconnected by common or complementary patterns of demand or supply relations. Using register data of business establishments, it identifies economic clusters and analyses their pattern based on postcodes at different time slices during the period 1983–2002. The study shows how the advanced services occupy the urban centre and key sub centres. The Information and Communication Technology (ICT) cluster is mainly concentrated in the north part of the city and circles the urban centre, and the main manufacturing clusters are evolved in the key sub centers. This type of outcomes improves understanding of urban-economic dynamics, which can support spatial and economic planning. [Copyright &y& Elsevier]

Abstract: External wall insulation plays an important role in building energy consumption through affecting cooling and heating energy uses. In this paper, a study on the effects of external wall insulation thickness on annual cooling and heating energy uses under different Chinese climates is reported. Firstly, two indexes: Energy Gain Ratio (EGR) and Relative Variation Ratio (RVR) of the sum of annual cooling and heating energy uses, to assess the effects of external wall insulation thickness on energy saving potential are introduced. Secondly, a model space having four different exterior zones facing four different orientations in an office building is presented and the settings of the model space described. Lastly, the simulated annual cooling and heating energy uses for the four different exterior zones at different external wall insulation thicknesses under three different climates in China, Guangzhou, Shanghai and Beijing, are reported. The results suggested that energy saving was significant by increasing the external wall insulation thickness in exterior zones facing all orientations under Beijing’s climate, since the heating energy use was dominant and can be reduced remarkably with the increase in insulation thickness. Under Shanghai’s climate, increasing external wall insulation thickness to over 26mm would not reduce the sum of annual heating and cooling energy uses in the south-facing exterior zone, but would help save energy in exterior zones facing the other three orientations. For all exterior zones under Guangzhou’s climate, it was, however, hardly possible to reduce the sum of annual heating and cooling energy uses by increasing the external wall insulation thickness. [Copyright &y& Elsevier]

Abstract: This paper reports on a qualitative research study into the test-taking strategies employed in completing two picture prompt writing tasks—Situational Writing and Interpretational Writing in the Beijing Matriculation English Test. Think-aloud and retrospective interview protocols were collected from twelve Chinese students representing two key and two ordinary senior high schools in both urban and suburban areas of Beijing. The researcher also conducted in-depth interviews with the students’ English teachers to explore issues raised by their students. The research findings suggest that driven by the high stakes involved in the test, students have developed a full set of test-taking strategies through coaching and exhibited skillful manipulation of these strategies. Moreover, with its original intention badly distorted, Interpretational Writing has become a “risky” task. Students are unwilling to freely express their own ideas. Instead they try to guess test developers’ intent. Therefore, Interpretational Writing might fail to achieve one of its goals: measuring creative thinking. The researcher also points out that more efforts should go into identifying the sources of certain test-taking strategies and clearing any possible misunderstandings between test developers and teachers. [Copyright &y& Elsevier]

Abstract: In recent years, wetland restoration measures have created extensive concerns globally. The theory and practice of restoring wetland vegetation diversity in wetlands through soil seed banks is discussed in this paper. A comparative study on soil seed bank and species composition in Yeyahu Wetland, Beijing, was conducted in 2007. Species and quantities of seeds from 12 sample sites were counted and measured by the seed-germinating method. After germination, 27 species belonging to 16 families and 23 genera were recorded, with an average of 11.75 species per sample site, and total average density of 24831.0individuals/m2. There were significant differences between the soil seed bank and vegetation in spring, summer and autumn, with similarity coefficients of 0.2620±0.0868, 0.2580±0.0778 and 0.1953±0.0452, respectively. Also in 2008, by using the seed bank technique, vegetation diversity was restored in a degraded wetland near Maying River of Yeyahu Wetland through the processes of spot selection, topographic surveying, water level monitoring, and vegetation management. The results showed that in the restored regions, both species and diversity coefficients of vegetation observably increased: 73.68% of the hydrophytic species we discovered were transplanted from provenance regions; germination of seeds in the soil lasted until late September; and many species completed their life history and produced new seeds to renew the seed bank. In addition, the results suggested that seed bank technique not only increased richness and multiplicity of vegetation, but also provided food chains with animal diversity in wetlands. [Copyright &y& Elsevier]

Abstract: A novel solar building cooling heating and power (BCHP) system driven by solar energy and natural gas is proposed in this paper. The performance of the presented system is greatly dependent upon the operation strategy. The primary energy consumption (PEC) and pollutant emissions of the solar BCHP system in following the electricity loads (FEL) and following the thermal loads (FTL) operation strategies are estimated based on life cycle assessment (LCA). Furthermore, three most important energy-related environment problems and human health issues, global warming, acid precipitation and respiratory effects, are considered to assess the environmental impacts of the system. In order to evaluate the comprehensive benefits achieved by the solar BCHP system in different operation modes, grey relation theory is employed to integrate the energetic benefits with environmental performances. Finally, a numerical case of the solar BCHP system for a commercial office building in Beijing, China is applied to compare the integrated performance in the FEL operation strategy with that of the FTL operation strategy. The results indicate that the energy saving and pollutant emissions reduction potentials of the FTL operation mode are the better than that of the FEL mode. [Copyright &y& Elsevier]

Abstract: To take into account reasonably the safety requirements of the disabled on emergency evacuation in the design, usage, management and emergency response of public places, the authors of this paper organized on-site experiments for 100 disabled individuals (40 people with no supporting tools, 20 people using a single crutch and 40 people two crutches) and 17 healthy people at a subway station in Beijing. The experiments were designed to measure the unimpeded free walking speed of the participants during horizontal and stair ascending/descending movement, and to assess the possible impact of passage width on movement speed. Based on the results of the tests, the authors systematically analyzed the speed variation patterns with disability grade, gender and passage width. The validity of the value of an important parameter for evacuation safety design in the prescribed fire codes in mainland China, the width of a single stream of people, is assessed. Finally the results of the experiments are compared with that from other researches to identify the similarities and differences between them. [Copyright &y& Elsevier]

Abstract: To improve the air quality during the 2008 Beijing Olympic Games, the Beijing Municipal Government enforced a series of emission control measures. This provided a valuable case study to evaluate the effectiveness of these aggressive measures on mitigating air pollution and improving the atmospheric environment. In this paper, we report the first results of the chemical and Sr isotopic compositions of the rainwater in Beijing during the 2008 Olympic year. The ionic composition of samples show that Ca2+ and NH4 + were the dominant cations, accounting for about 76–97% of the total cations, and that SO4 2− and NO3 − were the major anions, accounting for 61–91% of the total anions measured. Using Na as the indicator of marine origin and Al as that of terrestrial inputs, the proportions of sea salt and terrestrial elements were estimated from elemental ratios. The calculated results indicate that the major chemical components were mainly of non-sea-salt origin. Good correlation between Ca2+ and Sr2+ (R 2 =0.85) in rainwater samples indicates the potential of Sr as a provenance tracer for Ca. Sr2+ concentrations in rainwater samples ranged from 0.01 to 2.87μmoll−1, with 87Sr/86Sr ratios from 0.7092 to 0.7109. All of the samples had a 87Sr/86Sr ratio higher than that of seawater. The 87Sr/86Sr isotopic and elemental ratio systems show that the data set of rainwater was mainly distributed between the seawater end-member (~0.70917) and the soil dust end-member (0.7111–0.7115), and the analysis indicate that the effect of anthropogenic inputs could decrease in 2008. Comparisons of the chemical composition of the rainwater in different periods show that all chemical components, except NH4 +, had the lowest concentration levels during the Olympic Game period. The VWM concentrations of major ions in the rainwater decreased significantly during the Olympic period by up to 29% for SO4 2−, 39% for NO3 −, 38% for Ca2+, 51% for Mg2+, 57% for K+, and 44% for Na+, compared with the pre-control period. The concentrations of almost all species decreased during the 2008 Olympics, most likely due to both strict emission controls and favorable meteorological conditions. [Copyright &y& Elsevier]

Abstract: As a significant factor in urban planning, traffic forecasting and prediction of epidemics, modeling patterns of human mobility draws intensive attention from researchers for decades. Power-law distribution and its variations are observed from quite a few real-world human mobility datasets such as the movements of banking notes, trackings of cell phone users’ locations and trajectories of vehicles. In this paper, we build models for 20 million trajectories with fine granularity collected from more than 10 thousand taxis in Beijing. In contrast to most models observed in human mobility data, the taxis’ traveling displacements in urban areas tend to follow an exponential distribution instead of a power-law. Similarly, the elapsed time can also be well approximated by an exponential distribution. Worth mentioning, analysis of the interevent time indicates the bursty nature of human mobility, similar to many other human activities. [Copyright &y& Elsevier]

Abstract: In this paper, we reconstructed the spatial organization of Western medical services in Beijing city during the Republican period using a recently completed Republican Beijing GIS dataset. The primary objective is to explore the utility of spatial analytical methods, such as hotspot analysis and geographically weighted regression (GWR), in studying the spatial patterns of Western medical services. Our study is successful in depicting the spatial structure of Western medical services in the city. In addition, our analysis offers a preliminary but holistic view of the spatial relationships between Western medical services in the city and traditional Chinese medicine, population distribution, temple locations and industry-commerce patterns. [Copyright &y& Elsevier]

Abstract: This paper aims to discuss innovative plan models for Chinese cities that are currently under rapid development. The study considers Complexity Theories of Cities as the theoretical basis and applies a holistic approach in city planning by recognizing the complex nature of city. It strives to integrate the diverse local structure in social and spatial aspects with the ambition and demand of city''s expansion. Digital sequence simulation is used as an innovative tool to represent local activities, promote interventions and predict possible self-organization process in the future. The study arrives at an open scenario, the feasible prospect. A conclusion is drawn to reflect the process and achievement and propose future works for this research. [Copyright &y& Elsevier]

Abstract: Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have obtained increasing attention; however, few analytical methods are available for sensitive identification of these compounds in water. In this paper, we developed a highly sensitive method for simultaneous determination of nine OH-PBDEs in water by using hydrophilic–lipophilic balanced cartridge extraction, silica cartridge purification, and the combination of derivatization with liquid chromatography–electrospray tandem mass spectrometry. The effective sample pretreatment process and greatly increased instrumental sensitivity by derivatization allow for the quantification of nine OH-PBDEs at a method detection limit of 0.04–3.5pg/L with 1-L wastewater treatment plant effluent or river water. This method was applied to wastewater effluent and river water samples collected in Beijing, China, where two OH-tetraPBDEs were detected at concentrations ranging from 0.63 to 1.0pg/L (5-OH-BDE-47) and from 0.92 to 1.3pg/L (6-OH-BDE-47). [Copyright &y& Elsevier]

Abstract: In this paper, a planning analysis of implementing low impact development (LID) type of stormwater best management practices (BMPs) for urban runoff control is presented. The Beijing Olympic Village (BOV) residential area in China was used as a case study. The original BOV stormwater system incorporated some LID BMPs such as porous pavements, green roofs and rainwater cisterns. After the 2008 Olympics, the BOV was converted to a residential complex and some stormwater facilities were modified for landscaping purposes. The performance of the original stormwater management system at the BOV residential area was first evaluated by using the model BMPDSS. BMPDSS is a best management practice (BMP) planning and analysis tool, which is capable of simulating BMP performance and optimizing BMP placement and design. The Storm Water Management Model (SWMM) was used to simulate pipe network hydraulics for the BOV. The present study then examined the performance associated with the BMP modifications for landscaping purposes, and then further BMP modifications designed for enhancing runoff control capabilities of the system. Using the 2008 rainfall data for Beijing, peak flow rate and runoff volume reductions under the three scenarios were calculated by using the coupled SWMM–BMPDSS framework and compared. Optimization analysis for BMP design aimed at achieving either maximum runoff control or total minimum system cost was then conducted. The results were used to form recommendations to the Beijing authorities for modifying the present stormwater management system in order to achieve more runoff control benefits. [Copyright &y& Elsevier]

Abstract: Aerosol Robotic Network (AERONET) aerosol optical depth (AOD) and almucantar retrievals (single scattering albedo (SSA) and aerosol size distribution) from 2005–2009 in Beijing and Kanpur are used to analyze differences and similarities in aerosol optical properties over these two regions. The examination of monthly mean AOD (440 nm) shows that maximum and minimum values occurred in summer and winter, respectively, for Beijing, while the range in AOD in Kanpur was lower. Precipitation in both Beijing and Kanpur peaked in summer; however, the columnar water vapor (CWV) exhibited a high correlation with AOD in Beijing (R 2 = 0.79) but had a weak relationship with AOD in Kanpur (R 2 = 0.13). The Angstrom exponent (α, 440–870 nm) generally increased linearly as the fine mode fraction (FMF) of AOD (500 nm) increased for FMF < 90% in both regions, with a high correlation of R 2 > 0.96. However a clear decrease in α for FMF > 90% found in Beijing is not shown distinctly in Kanpur, and is mainly due to the higher aerosol loading in this FMF bin at Beijing (AOD at 440 nm > 2.2) which results in a stronger coagulation of fine mode particles. Bimodal seasonally-averaged size distributions reveals similar aerosol mixtures composed of fine pollution particles and coarse dust particles in both regions. The analysis of spectral SSA as a function of α is emphasized in this paper. The average SSA at 440 nm in both regions shows a similar low dynamic range of ∼0.03 for α < 1.4. The obvious increase in SSA at 440 nm for α > 1.4 in both regions can be attributed to a higher FMF leading to fine mode coagulation. However, the distinctly smaller increase in Kanpur suggests that fine mode aerosols at Beijing are less absorbing than those at Kanpur. The visibly lower SSA at 675 nm at Kanpur compared to that at Beijing for α > 0.4 is due to a larger find-coarse mode separation radius of ∼0.76 μm in Beijing versus a value lower than ∼0.58 μm in Kanpur. Another reason lies in the weaker absorption by fine mode aerosols in Beijing. The distinctly lower near-infrared SSA in Kanpur when α < 1.4, compared to Beijing, may be attributed to lower aerosol concentrations in all α bins, resulting in less aggregation of absorbing black carbon particles on coarse particles in Kanpur. The classification of aerosol properties shows that the AOD accumulation mode in all seasons, even including spring, in Beijing and in post-monsoon and winter seasons in Kanpur can be attributed to fine particle coagulation or hygroscopic growth; during pre-monsoon and monsoon seasons in Kanpur, it is due to coarse mode particle accumulation or cloud contamination. [Copyright &y& Elsevier]

Abstract: Operation mode of combined cooling heating and power (CCHP) system determines its energetic and environmental performances. This paper analyzes the energy flows of CCHP system and separated production (SP) system. The fuel energy consumptions of CCHP system following electrical demand management (EDM) and thermal demand management (TDM) are deduced respectively. Three indicators: primary energy saving, exergy efficiency and CO2 emission reduction, are employed to evaluate the performances of CCHP system for a commercial building in Beijing, China. The feasibility analysis shows that the performance of CCHP system is strictly dependent upon building energy demands. The selection of CCHP operation modes is systemically based on building loads, CCHP system and local SP system. The calculation results conclude that CCHP system in winter under EDM achieves more benefits than in summer. The sensitivity discussion indicates that the coefficient of performance for cooling and the efficiency of electricity generation are the most sensitive variables to the energetic and environmental performances of CCHP system. [Copyright &y& Elsevier]

Abstract: The use of groundwater for cooling and heating purposes is of interest from both the economical and the ecological perspective. The groundwater heat pump (GWHP) system utilizes groundwater as alternative renewable and clean energy source for space heating and/or cooling, withdraws water from a production well, passes it through a heat exchanger and discharges the water into an injection well. By utilizing the relatively stable temperature of groundwater, GWHP system can achieve a higher coefficient of performance. Due to the utilization of groundwater stored in the aquifer, the assessment of the hydraulic capacity of the aquifer based on numerical groundwater models is always needed for the optimum design and the efficient performance of GWHP. In this paper, numerical methods of underground heat-water transfer, energy balance method and thermal storage method were presented to calculate the capacity of unit area of shallow groundwater aquifer. The model results indicate that the numerical method, which is based on performance efficiency of GWHP, represents the behaviour of groundwater pumping/recharging processes, and serves better than energy balance method and thermal storage method, in addition it has been proven itself that this method has the advantages of energy saving and environmental protection. The calculated capacity is positively related to aquifer thickness. It is found that it is easy for ground water recharge in alluvial and pluvial fan located at the piedmont, while the calculated capacity is relatively smaller compared with that of south-east plain where it is not easy for groundwater recharge. [Copyright &y& Elsevier]

Abstract: The concentrations, spatial distribution and compositional patterns of extensively used hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in urban dustfall in a metropolis-Beijing are presented in this paper. The potential sources are discussed and soil burdens are predicted based on the fluxes. The hotspots in commercial areas are identified by spatial distribution maps and the fractional value isomers indicates that dustfall in urban Beijing are affected by both current and historical usage of DDTs. It is worth noticing that there is possible application “dicofol-type of DDTs” in Beijing. The measured atmospheric deposition flux is 1.14×105 ngh−1 m−2 for HCHs and 1.47×105 ngh−1 m−2 for DDTs, respectively. However, when compared with atmospheric deposition flux, the volatilization flux estimated from concentrations in soils by fugacity model is significantly lower for HCHs (2.41ngh−1 m−2) and DDTs (0.07ngh−1 m−2). The net atmospheric flux to the soil suggests that the levels of HCHs and DDTs in soil are dominated by atmospheric deposition and the urban soil in Beijing would be a sink for HCHs and DDTs in the long term. [Copyright &y& Elsevier]

Abstract: A cold neutron radiography/tomography instrument was designed and will soon undergo construction at the Compact Pulsed Hadron Source (CPHS) of Tsinghua University, China. In this paper, we report the physical design of the instrument and propose a scheme to implement several techniques at a later phase to enhance the utilization of the flux on larger samples. This includes code-aperture, grating-based imaging, prompt gamma-ray analysis and 3D emission CT. [Copyright &y& Elsevier]

The minimum ecological water requirements of an urban river system and water deployment are key elements in integrated water resources planning and urban ecological construction. Based on a review of ecological water requirement calculation methods and considering the different ecological functions of an urban river system, the ecological function method was used in this paper to calculate the components of the ecological water requirements of an urban river. An envelope curve-based method was proposed for assessing the minimum ecological water requirements of an urban river system. Water resources deployment strategies designed to meet the minimum ecological water requirements were described. Then, the minimum ecological water requirements of the urban river system in Beijing central region, selected as a case study, were investigated. The key parameters for assessing the minimum ecological water requirement in the Beijing urban river system were determined. Based on the ecological objectives and the current status of the different urban river systems within the Beijing central region, the minimum ecological water requirements were calculated. Different types of water sources, including rainwater, upstream water, and reclaimed water, were deployed to meet the ecological water requirements for the urban river system in the Beijing central region. [Copyright &y& Elsevier]

Abstract: Pipe breaks often occur in water distribution networks, imposing great pressure on utility managers to secure stable water supply. However, pipe breaks are hard to detect by the conventional method. It is therefore necessary to develop reliable and robust pipe break models to assess the pipe''s probability to fail and then to optimize the pipe break detection scheme. In the absence of deterministic physical models for pipe break, data-driven techniques provide a promising approach to investigate the principles underlying pipe break. In this paper, two data-driven techniques, namely Genetic Programming (GP) and Evolutionary Polynomial Regression (EPR) are applied to develop pipe break models for the water distribution system of Beijing City. The comparison with the recorded pipe break data from 1987 to 2005 showed that the models have great capability to obtain reliable predictions. The models can be used to prioritize pipes for break inspection and then improve detection efficiency. [Copyright &y& Elsevier]

Abstract: Beijing’s mountainous areas have an important ecological significance because they are ecological conservation and water source protection areas of Beijing. The impact of precipitation on the vegetation coverage of Beijing’s mountainous areas is qualitatively analyzed using multi-temporal Landsat images obtained during the last 20 years. Firstly, the influence of external factors, such as phenology and relative radiometric correction, on the normalized difference vegetation index (NDVI) are removed by the normalization of remote sensing images for different periods. Then, the vegetation coverage is calculated using the method of the dimidiate pixel model. Finally, based on that, the relationship between precipitation in different seasons and change of vegetation coverage is discussed. The results indicate that the mean vegetation coverage has the same change trends with winter and summer precipitation, but an opposite change trend with spring precipitation. The paper provides a theoretical basis and data support for further research on driving models of natural vegetation restoration in Beijing’s mountainous areas. [Copyright &y& Elsevier]

This paper presented a thermodynamic synthesis that involved resource accounting, evaluation and modeling of urban ecosystems based on embodied cosmic exergy (EcE), which redefined embodied exergy with the cosmic microwave background radiation (CMBR) as the reference for solar exergy. In a case study of the Beijing urban ecosystem, the major resources supporting the urban ecosystem, both from free natural resources and from the economy, were accounted for, analyzed and evaluated in the same units, Cosmic Joules (Jc). These indicators revealed the current performance of the Beijing urban ecosystem by considering five aspects of the system: EcE sources, EcE intensity, EcE welfare, environmental impacts and economic efficiency. Moreover, through the combination of the EcE synthesis with a systems dynamics, this research constructed an embodied cosmic exergy-based urban system model (EESM) using Beijing as an example of urban development. The results show that the 10 years from 2010 to 2020 will be very critical for the sustainable development of Beijing because many key factors, such as water resources, wastes and urban assets, might be confronted with great changes during this period. These changes will inevitably transform the urban system not only in its external circumstances but also in its inner structure and may lead to serious consequences. Of all the necessary resources, the most sensitive factor is water supply. [Copyright &y& Elsevier]

Abstract: In this paper, 240 abnormal infrasound signals observed at Beijing (39.87°N, 116.48°E) and 92 M ≧7.0 worldwide earthquakes during 2002–2008 are investigated. It is found that about 85% the earthquakes are preceded the signals by 1–30days and the greater M ≧7.6 earthquakes are most likely leaded by 1–10days. The maximum amplitude of the abnormal infrasound signal generally exceeds 8Pa in sound pressure. The statistical analyses further indicate that the amplitude of the abnormal signals is proportional to the magnitude the associated forthcoming earthquake but inversely to the distance from that earthquake to the observation station. [Copyright &y& Elsevier]

Abstract: This paper is to investigate the behavior of residents towards electrical and electronic waste (e-waste) recycling in Beijing. For this purpose a large sample questionnaire survey was performed to explore the residents’ characteristics of recycling behavior and preference of e-waste recycling pattern. Besides, the willingness of residents to participate in e-waste recycling was also assessed in our study. For this a logistic regression model was developed to estimate and explain residents’ willingness in e-waste recycling. The model showed that Convenience of recycling facilities and service, Residential conditions, Recycling habit and Economic benefits are four determinants of Beijing residents’ willingness and behavior in e-waste recycling. And centralized recycling pattern by professional recovery spots would have a broad prospect if various kinds of channels can be provided to make the residents feel more convenient in e-waste recycling. [Copyright &y& Elsevier]

Abstract: Sustainable development of geothermal resources is the key to prolong the commercial life of geothermal fields. This paper uses two well-known geothermal fields in China, with long histories of production, to demonstrate how sustainability can be quantitatively evaluated, and to highlight the essential differences between sustainable and non-sustainable development schemes. After examining the complex nature of sustainability evaluation, fuzzy synthetic evaluation is applied as a tool for the quantitative sustainability rating of geothermal reservoirs. The evaluation procedures include systemic criteria selection, weighing, individual criterion evaluation and finally final multi-criterion decision analysis evaluation. The sustainability of a limestone reservoir in the urban sector of Tianjin is rated rather low because of insufficient levels of water injection. On the contrary, the carbonate rock reservoirs of the Xiaotangshan geothermal field in suburban Beijing have a strong sustainability rating, mainly due to high injection rates. [Copyright &y& Elsevier]

Abstract: Study of human activities in space and time has been an important research topic in transportation research. Limitations of conventional statistical methods for analysis of individual-level human activities have encouraged spatiotemporal analysis of human activity patterns in a space–time context. Based on Hägerstrand’s time geography, this study presents a space–time GIS approach that is capable of representing and analyzing spatiotemporal activity data at the individual level. Specifically, we have developed an ArcGIS extension, named Activity Pattern Analyst (APA), to facilitate exploratory analysis of activity diary data. This extension covers a set of functions such as space–time path generation, space–time path segmentation, space–time path filter, and activity distribution/density pattern exploration. It also provides a space–time path based multi-level clustering method to investigate individual-level spatiotemporal patterns. Using an activity diary dataset collected in Beijing, China, this paper presents how this Activity Pattern Analyst extension can facilitate exploratory analysis of individual activity diary data to uncover spatiotemporal patterns of individual activities. [Copyright &y& Elsevier]

Abstract: Presented in this paper is a low-carbon assessment for wastewater treatment by a constructed wetland as ecological engineering. Systems accounting by combining process and input–output analyses is applied to track both direct and indirect GHG emissions associated with the wastewater treatment. Based on the detailed assessment procedures and the embodied GHG emission intensity database for the Chinese economy in 2007, the GHG emissions embodied in both the construction and operation stages of a pilot constructed wetland in Beijing are investigated in concrete detail, with parallel calculations carried out for a cyclic activated sludge plant as a typical conventional wastewater treatment system for comparison. With the overall embodied GHG emissions taken into account, the constructed wetland is shown to be remarkably less carbon intensive than the conventional wastewater treatment system, and the contrast in GHG emission structure is also revealed and characterized. According to the results, the ecological engineering of the constructed wetland is considered to be favorable for achieving the low-carbon goal. [Copyright &y& Elsevier]

Abstract: For decades through the 1980s, housing units in major Chinese cities were “bonded” to jobs as they were located together with or very close to places of employment within large, walled danwei compounds. From the 1990s, accelerated suburbanization of population in major Chinese cities fueled by urban redevelopment, urban land reform and urban housing reform has fundamentally altered the jobs–housing spatial relation. The “spatial bond” that existed between urban jobs and urban housing for decades has dissolved and is being replaced by a prominent “spatial mismatch” when the jobs–housing relationship becomes increasingly imbalanced in space. This paper examines the new jobs–housing imbalance by assessing the extent of employment–residence spatial mismatch in Beijing. This analysis based on statistical data shows that the spatial imbalance between employment and population has become increasingly pronounced over time across urban districts. It is especially evident in the inner city where the loss of residents continues and the concentration of employment persists. The analysis of survey data, which focuses on people’s commuting patterns and travel behaviors, also provides strong evidence of spatial imbalance. Meanwhile, it reveals some of the impacts on job accessibility and other aspects of urban life. This study contributes to the understanding of how suburbanization has been unfolding in major Chinese cities and how it has been transforming urban development and urban life. It also adds to the understanding of the spatial dynamics of employment–housing relationship based on Beijing’s experience and sheds lights on the multifarious nature of the spatial mismatch problem. [ABSTRACT FROM AUTHOR]

Abstract: As the result of rapid and incomplete transition from a planned economy to a market one, urban housing market has been seriously distorted in China. In order to ensure the appropriate supply of housing, housing size regulations have to be established, which necessitates good knowledge on the preferential size of housing. This paper proposed an empirical framework to identify the preferential size of housing perceived by people. A hedonic approach was adopted to analyze the willingness of urban households to pay for the size of their accommodations. With the transaction price data of second-hand apartments in Beijing, the marginal benefits of urban households in relation to housing size were investigated, which revealed that 50–60m2 and 80–190m2 (including shared public space) were more highly valued than other sizes of apartment housing in Beijing. Further examinations of the market balance of supply and demand as well as the impact of bubble effect on market conditions demonstrated that the results were reliable. Based on the implications of the results, suggestions were made for the implementation of housing size regulation and relevant policies. [ABSTRACT FROM AUTHOR]

Abstract: This paper deals with the limitations of visual interpretation of high-resolution remote sensing images and of automatic computer classification completely dependent on spectral data. A knowledge-rule method is proposed, based on spectral features, texture features obtained from the gray-level co-occurrence matrix, and shape features. QuickBird remote sensing data were used for an experimental study of land-use classification in the combination zone between urban and suburban areas in Beijing. The results show that the deficiencies of methods where only spectral data are used for classification can be eliminated, the problem of similar spectra in multispectral images can be effectively solved for the classification of ground objects, and relatively high classification accuracy can be reached. [ABSTRACT FROM AUTHOR]

Abstract: Since the pioneer wide-angle seismic profile along the Yadong–Gulu rift acquired in 1974 by the ex-Institute of Geophysics, Chinese Academy of Sciences (CAS), several research programs aimed to deep geophysics, performed thanks to the participation of Chinese national and international institutions, have been developed during last 35years, including 23 wide-angle seismic profiles with total length of about 6000km. These profiles are unevenly distributed, most of them in eastern Tibet and few profiles in western Tibet. In this paper, we make a summarized presentation of all these wide-angle seismic profiles and provide an overall view of the seismic velocity structure of the crust beneath the broad Tibetan plateau, which is the product of the continuous convergence and collision of the Indian and Eurasian plates since about 50Ma ago. Different patterns of crustal thickness variation related to the tectonic blocks and along suture zones of the region are displayed. The crust thickness is confirmed to be about 70–75km under southern Tibet, and 60–65km under northern, northeastern and southeastern Tibet. The leading edge of the subducted lithosphere reaches the northern margin of the plateau and directly contacts with Tarim Basin. Westward of the 90°E boundary, the Indian crust is moving towards the northern edge of the plateau and collides with Tarim Basin at 80°E while reach the Bangong–Nujiang suture belt at 88°E; eastward of the 90°E boundary, the northern edge of the crust should be at 50–100km south of Bangong–Nujiang suture. The results supply helpful constrains to understand the mechanism of the continent–continent collision and its consequences in the plateau and neighbouring areas. [Copyright &y& Elsevier]

Abstract: It is difficult for an air source heat pump (ASHP) system to provide enough heat for heating buildings with high working efficiency when it runs at low ambient temperature. An advanced ASHP system that, in the paper, composes a main refrigerant circle and a bypass circle would supply a lot of heat for the buildings in Beijing at same working condition. In the system, the bypass refrigerant can be used to increase the density of refrigerant at the inlet of the hermetic compressor employed in refrigeration cycle, and so, the advanced ASHP could appear relative high efficiency even when it runs at low ambient temperature. The assistant throttle apparatus in the bypass circle is a part of capillary that was enlaced tightly around to the compressor. The capillary can be used to reuse the heat from surface of the compressor. Compared with a traditional system, the advanced ASHP system could provide three times heat capacity and more than 35% of efficiency at the working condition −10°C. [ABSTRACT FROM AUTHOR]

Abstract: An integrated wetland system (IWS) including constructed wetlands (CWs) and modified natural wetlands (NWs) for wastewater treatment to replenish water to wetlands located at the Beijing Wetland School (BWS) in Beijing, China, is presented in this paper. The synergistic effects of CWs and NWs on treated water quality are investigated. The IWS is proved to be an effective wastewater treatment technique and a better alternative to alleviate the water shortage for conservation of wetlands based on the monitoring data obtained from October 2007 to 2008. The results show that CWs and NWs play different roles in removing contaminants from wastewater. The COD removal efficiency in CWs is higher than that in modified NWs, whereas the modified NWs can compensate for the deficiency of CWs where a stable and sufficient rhizosphere is not fully formed in the start-up period. All removal rates of COD, TN, and TP in CWs and modified NWs vary from 50 to 70%, while the total removal rate of COD, TN, and TP in IWS is about 85–90%. The operational results show that the maximum area loading of organic pollutants in modified NWs (65kg/had) is slightly higher than the empirical one (60kg/had) recommended by for free water surface wetlands. [ABSTRACT FROM AUTHOR]

In this paper, emergy accounting (EA) and life cycle assessment (LCA) methods are employed to investigate a typical urban wetland park, the Green Lake Urban Wetland Park (GLUWP) of Beijing, in terms of its environmental and capital inputs, ecosystem services and organic matter yields, environmental support, and sustainability. The LCA method is also used to obtain a quantitative estimation of the environmental impact of discharges during the entire life cycle of the GLUWP. Various emergy-based indices, such as emergy yield ratio (EYR), environmental load ratio (ELR), emergy sustainability index (ESI), net economic benefit (Np), and environmental impacts of process-based LCA, including global warming potential (GWP), eutrophication (EU), nonrenewable resource depletion (RU), energy consumption (EN), acidification potential (AP), photochemical oxidant creation potential (POCP), particulate matter (PM) and wastes (W), are calculated. The results show that the GLUWP has higher proportions of renewable resource input, less pressure on the environment, more environmental support and better ecological and economic benefits, which can be considered as an environment-friendly and long-term sustainable ecological practice, compared with another constructed wetland in Beijing. Meanwhile, the dominant environmental impact is induced by POCP with the construction phase contributing the most on the entire life cycle. It is expected that increasing green area, extensively using environment-friendly materials, optimizing construction techniques and reducing power consumption can promote the sustainability of the GLUWP. [Copyright &y& Elsevier]

Abstract: This paper reports findings of a recent field study that characterized the on-road emissions of individual diesel vehicles in and around Beijing, China during November and December of 2009. We successfully sampled 230 individual trucks on 4 major expressways around the city as well as 57 individual buses in the city using refined mobile chasing techniques and fast response instruments. Emission factors (EF) for carbon monoxide (CO), black carbon (BC) and particulate matter with diameters less than 0.5 μm (PM0.5) are derived from the measurements, which are consistent with the results from laboratory dynamometer tests. The PM0.5 number emission factor distributions demonstrate consistent bimodal modes with peaks around 10 nm and 80 nm, while the mass emission factor distributions demonstrate a unimodal maximum around 110 nm for a majority of the trucks. The BC emissions are shown to be highly correlated with the mass emission of particles with 100–250 nm diameters, which are in good agreement with the results from previous studies. A number of important policy implications are discussed based on the results from this study. First, we identified “heavy emitters” in the on-road fleet we encountered, finding that 5% of diesel trucks in this sample are responsible for 50% of total BC emissions, and 20% of the trucks are responsible for 50% CO and PM0.5 number emissions, 60% PM0.5 mass emissions and over 70% of BC emissions. This suggests that emissions control programs should include identifying and removing heavy emitters from the road or improving their emissions. Second, the BC and PM0.5 number emission factors of trucks registered in regions outside Beijing are significantly higher than those of Beijing-registered trucks, suggesting that improving engine and fuel standards in Beijing alone is not sufficient in reducing the traffic-related air pollution in Beijing. Third, the significantly lower emissions from Euro IV and CNG buses compared to the Euro II and Euro III buses support that introducing clean-burning buses is an effective way to reduce the overall vehicle emissions for the pollutants studied. Fourth, our refined chasing method demonstrates a cost-effective approach to characterize the emissions from a large number of on-road diesel vehicles. Further studies with large sample sizes are critical to constructing more accurate mobile emission inventories to represent the on-road vehicle population. [Copyright &y& Elsevier]

Abstract: This paper proposes a method for forecasting the ionospheric critical frequency, f 0F2, 1h in advance, using the support vector machine (SVM) approach. The inputs to the SVM network are the time of day, seasonal information, 2 month running mean sunspot number (R2), 3 day running mean of the 3h planetary magnetic ap index, the solar zenith angle, the present value f 0F2(t) and its first and second increments, the observation of f 0F2 at t−23h, the 30-day mean value at time, t, f mF2 (t) and the previous 30 day running mean of f 0F2 at t−23h f mF2(t−23). The output is the predicted f 0F2 1h ahead. The network is trained to use the ionospheric sounding data at Haikou, Guangzhou, Chongqing, Lanzhou, Beijing, Changchun and Manzhouli stations at high and low solar activities. The performance of the SVM model was verified with observed data. It is shown that the predicted f 0F2 has good agreement with the observed f 0F2. The performance of the SVM model is superior to that of the autocorrelation and persistence models, and that it is comparable to that of the neural network model. [ABSTRACT FROM AUTHOR]