Search

Most of the old rural houses in Beijing are single-layer buildings with double-sloping roofs. Under an earthquake, the gable is prone to an outward tilt, and the structure is prone to collapse as a whole. In view of the structural characteristics of the existing rural houses in Beijing, a reinforcement technology is proposed, in which the embedded steel frame reinforcement is mainly used, supplemented by a steel plate strip reinforcement. A 1/4 masonry structure model is designed for a shaking table test. A full-scale model is established in a finite element simulation analysis. The results show that the longitudinal wall is seriously damaged, and the gable has a considerable outward inclination under earthquakes. However, owing to the reinforcement effect of the steel frame, the overall collapse of the structure is avoided. The steel strip can effectively restrain the outward inclination of the gable and ensure safety of personnel. [ABSTRACT FROM AUTHOR]

Reasonable resource potential calculation is the basic premise for the country to formulate planning and carry out rural housing land consolidation, which can deepen the research on the economical and intensive use of rural construction land. This paper evaluates farmers' area demands of rural housing land by using the consumption utility function, analyzes the spatial pattern characteristics of demand and potential, and puts forward suggestions for the resource optimization of rural housing land based on the survey data of 613 farmers and land use data in the Pinggu District of Beijing in 2005 and 2018. Research shows that the utilities of life, production, and the ecological are carried and measured by the corresponding internal land-use structure of rural housing land. The proportion of life land area was the largest, and the life and production land area decreased from plain to mountain, from 119.76 m2 to 89.07 m2 and from 44.87 m2 to 32.85 m2, respectively. The average area potential is 395.64 m2 and the change range is −30.35–1413.75 m2, which is basically in accordance with the normal distribution. The area potential can be divided into five grades, which are expressed by I, II, III, IV, and V in order of potential from small to large by using the natural fracture method. The utility needed should be enhanced and expanded, and the redundant utility should be removed and socialized in the village. The resource optimization and allocation of rural housing land should be promoted according to the idea of regionalization and classification. It provides scientific support for the reform of rural housing land. [ABSTRACT FROM AUTHOR]

Inside Beijing are hundreds of urban villages. Originally farming villages, now engulfed by urban expansion, they persist due to China's segregated urban-rural property system. Inhabitants are often still classed as peasants, despite being inside the city. Since most have had their agricultural land requisitioned for urban construction, they instead build multiple extensions to their houses to rent to rural migrants seeking cheap accommodation. In some cases, village populations have increased tenfold as migrants have flooded in, causing cramped conditions and overloading village infrastructure. Urban villages have in recent years emerged as key sites of ideological and political contestation. For local officials and planners envisioning gleaming world cities brimming with advanced technology and highly skilled workers, these are dirty and backward "urban cancers," enclaves of the "low-end population," and obstacles to their visions of the city as embodiment of global modernity. An opposing set of scholars and policy makers view these villages as essential to city life, channels for low-cost labor to service urban elites, and gateways to modernity for those formerly excluded. Within the urban villages, groups of migrant-activists defy the statist vision of the city. Through cultural performances and visual representations, they struggle to promote an urban modernity in which they are included as active participants. This article explores how Beijing's urban villages constitute a key site of ideological contestation over what the city should be, and whom urban life is for. [ABSTRACT FROM AUTHOR]

Context: Located between urban area and rural area, urban–rural fringe is challenged with urbanization related social-ecological problems. Accurately identifying the urban–rural fringe can help to integrated urban–rural development planning, especially in metropolitan region. Among the various case studies to identify the urban–rural fringe, land use degree and impervious surface area are widely used. However, both indexes are only focused on land development size, resulting in coarse identifying results. Objectives: It is aimed to propose a three-dimensional approach to integrating land development size, pattern and density, in order to accurately identifying the urban–rural fringe. Methods: Landsat TM and DMSP/OLS datasets were used to establish a three-dimensional index system consisting of land development size (LDS), land development pattern (LDP) and land development density (LDD). Self-Organizing Feature Map (SOFM) was applied to identify the urban–rural fringe of Beijing City, China. Results: From 2001 to 2009, the inner boundary of the urban–rural fringe had expanded to outside the fifth ring road. Likewise, the outer boundary moved from the fifth to the sixth ring road. The new urban development zone was the main area of urban expansion controlled by urban planning, where the increments of urban–rural fringe was 1273.5 km2, accounting for 75.24% of the whole city. Partial correlation analysis indicated that LDS played a leading role in SOFM clustering, but the spatial continuity of the urban–rural fringe was the best when it was integrated with LDP and LDD, especially the latter to comprehensively define and quantify land development intensity. Conclusions: The integration of land development size, pattern and density is effective to quantify land development intensity, and thus to identify the urban–rural fringe in metropolitan regions. [ABSTRACT FROM AUTHOR]

Purpose: Intensive urbanization decreases the self-regulation of urban ecosystems, leading to accumulation of persistent pollutants such as trace metals and metalloids in urban environments. Road-deposited sediments (RDS) are important carriers of trace metals and metalloid contaminants that could contribute to urban runoff pollution. This study aims to investigate the concentration and speciation systemically and assess the risks of trace metals and metalloids from RDS comprehensively. Materials and methods: Road-deposited sediments (RDS) were analyzed for As, Cd, Cr, Cu, Mn, Pb, and Zn, in terms of total concentrations, speciation, release, and risks at 23 sites across six land types (the rural-urban fringe, commercial, residential, industrial, traffic, and the natural areas) in Daxing District of Beijing, China, in April 2018. Risk factors evaluating different aspects included contamination levels and ecological risk, Igeo, and RI; source of metal (natural or anthropogenic), EF; bioavailability, RAC. Six particle sizes vs. metal concentrations were also analyzed for trace metals and metalloids from rural-urban fringe samples. Results and discussion: Obvious variations were found for the concentrations of Cr, As, and Cd in rural-urban area, especially for Cr. Industrial sites exhibited highest average values for all trace metals and metalloids except for As and Cu. Cr, Cd, and Pb in particular posed more risk. Traffic area showed signs of contamination for Cu, Pb, and Zn. Commercial and residential areas presented low ecological risk. However, there were signs of As and Cu contaminations in both areas, and of Pb in the residential area as well. No research sites were contaminated by Mn, despite the high concentration values. Although high contamination levels of Cr were found in many sites, the risk level of Cr was low. Generally, RDS with smaller particle size (< 80, 80–150, and 150–300 μm) possessed higher concentrations of trace metals and metalloids compared to larger size (300–500 and 500–1000 μm). Conclusion: The study showed that metals of high concentration do not always pose high risk. More attention should be paid to the systematical risk assessment of trace metals and metalloids than the concentration. [ABSTRACT FROM AUTHOR]

Currently, household heating systems in rural China primarily use coal. This low-efficiency heating method not only results in poor indoor comfort, but also contributes to indoor and regional air pollution. Split-type, low temperature air-to-air heat pumps (AAHPs) have been proposed to be a clean heating alternative to replace coal-burning stoves. This study performed field measurements of a AAHP product in two representative rural households in suburban Beijing, China, focusing on three goals: 1) to observe, analyze, and validate occupant control patterns of low temperature AAHPs in rural households; 2) to explore comfort indoor temperature levels in rural households and demonstrate the thermal comfort achieved as per the individual requirements of residents and space use; and 3) to learn the heating energy saving potentials achieved by considering occupant control patterns. Room temperatures and time-varying electricity consumption from February 6 to March 15 were monitored. Three occupant control patterns were observed and verified from the field measurements: 1) continuous daily operation of heat pumps, 2) intermittent operation, and 3) irregular operation. In addition, the observed indoor temperatures of both households ranged from 10 °C to 23.5 °C. By considering varied occupant control behaviors, the heating energy consumption reduction can be significant. This study indicated that using the low temperature AAHPs met individual thermal comfort requirements and had a great potential to reduce the heating energy consumption when considering different occupant control patterns. [ABSTRACT FROM AUTHOR]

Abstract: Diversity, complexity and change have become the hallmarks of contemporary Chinese rural settlements. However, the literature so far has paid insufficient attention to this phenomenon from the standpoint of functional transition and related land-use change. To fill in this gap, this paper explores the functional transition of rural settlement through analyzing land-use differentiation in a transect of Beijing. Land-use changes are presented along the differentiation of land-use structure and use change of rural housing. The results indicate that there is an obvious differentiation of land-use structure from near-urban countryside to the rural hinterland. Besides that, the use change of rural housing also has regional characteristics. They are different responses to the urban sprawl, respectively from the collective economic organization and single rural resident. The regional differentiation implies a functional transition in some rural settlements, including increases of non-agricultural function and urban servicing function. Quantitative evaluation of the functional intensity and its rules on spatial–temporal evolution still need to be approached in the future. [Copyright &y& Elsevier]

• Six LTAAHPs are installed in six rooms as the sole heating equipment for a family. • Usage of remote control for 75 days is considered as occupant control behavior. • Difference in heating control behavior of occupants in six rooms is studied. • Only power on/off, temperature set, and fan speed are frequently used by occupants. • The proposed method helps to further understand real-life heating demand. The traditional design principle of household heating is based on full-space and continuous heating, which does not match the true heating demands of different functional spaces and thus leads to energy wastage. In this study, we used low-temperature air-to-air heat pumps (LTAAHPs) for space heating and studied the heating demands of six different rooms by testing the control behavior of occupants using heating equipment in a rural house in Beijing, China. The diverse heating demands of the six rooms were observed for 75 days (from January 12 to March 27, 2017) and verified using field measurements: (1) the utilization rates of the LTAAHPs differ; the mean rates range from 6.0% to 58.7%, indicating that heating is not required 41.3%–94.0% of the time; (2) the desired temperature settings differ, with average temperatures ranging from 20.3 to 25.7℃; (3) the power inputs per unit heating area differ, with average inputs ranging from 34.2 to 97.4 W/m2; and (4) the energy consumption per unit heating area differs, ranging from 6.7 to 37.3 kWh/m2. These results indicate that different rooms have different heating demands, although they belong to the same household. This study helps to understand actual heating demands while saving energy based on the proper control of individual heating equipment. [ABSTRACT FROM AUTHOR]