Chen G.M.,Guangdong University of Technology |
Yang H.,Shenzhen Institute of Building Research Co. |
Lin C.J.,Guangdong University of Technology |
Chen J.F.,Guangdong University of Technology |
And 3 more authors.
Construction and Building Materials | Year: 2016
In the past decade, research on applications of recycled aggregate concrete (RAC), which uses recycled concrete aggregate (RCA), has attracted world-wide interest due to their social, environmental and potential economic benefits. One of the main concerns for using such concrete in buildings is its spalling in fire and post-fire residual mechanical properties. This concern may be alleviated by adding steel fibres to form steel fibre reinforced recycled aggregate concrete (SFRAC). In this study, 60 notched beams were tested to evaluate the fracture behaviour of SFRAC after exposure to elevated temperatures, including the modulus of elasticity (E), fracture energy (GF), initiation fracture toughness KIc ini and unstable fracture toughness KIc un. The effects of steel fibre volume content (0%, 0.5%, 1% and 1.5%) and exposure temperature (room temperature, 200 °C, 400 °C and 600 °C), were investigated. The test results show that the addition of steel fibres postpones the initiation of cracks and limits their opening in RAC, and thus significantly enhances the fracture energy and fracture toughness of RAC after exposure to high temperatures. © 2016 Elsevier Ltd
Liang W.,Tsinghua University |
Chen F.,Shenzhen Institute of Building Research Co. |
Yang X.,Tsinghua University
Indoor Air 2014 - 13th International Conference on Indoor Air Quality and Climate | Year: 2014
Volatile organic compounds (VOCs) play an important role in the indoor air quality with adverse health effects. Building materials are considered as one of the major VOC sources indoor. VOC emission measurements were mainly conducted in the environmental chamber with constant conditions. However, real building's conditions are very complicated and variable. Investigation into the material emission in the real building condition is rather rare. In this paper, we measured emissions of a "wet" material assembly in the environmental chamber and in two real houses. The results indicated that the "wet" material emissions between the chamber and real houses showed notable differences. The VOC initial emission rates of the "wet" material assembly in houses were lower than that in the small-scale environmental chamber. This study provides important first-hand data for understanding the key influences of various factors on material emissions.
Li B.,Harbin Institute of Technology |
Liu J.,Harbin Institute of Technology |
Gao J.,Shenzhen Institute of Building Research Co.
Journal of Wind Engineering and Industrial Aerodynamics | Year: 2015
The wind environments in real urban areas, which consist of various significantly non-uniform buildings, are completely different from those in regular building arrays or homogeneous underlying surface areas. Through boundary layer wind tunnel experimental studies, the present work aimed to investigate the possible effects of non-uniformity morphological parameters of buildings on the drag coefficient, with consideration given to the non-uniformity of the frontal area, density, shape, and layout of buildings. And a novel non-intrusive approach to drag measurement, based on wind pressure tests performed on three single buildings, was developed and compared with the direct measurement method. The experimental analyses indicate that among different cases, in general, the variation tendency of the drag coefficient of individual blocks positioned along a wind direction over a large planar area was approximated as an attenuation curve. Moreover, the drag coefficient results from the wind pressure tests vary by 10-20% from those based on direct measurements. Furthermore, when the layout was a diagonal-square network, which is considered for buildings that have better ventilation conditions, it was observed that the wind pressure difference coefficient of those pressure modules would increase. There are clear differences between an H-shaped building and a rectangular one, such as their distributions of the wind pressure difference coefficient and the fact that the H-shaped structure induces flow more intensely. In addition, the effect of changes in terrain roughness on the distribution of the surface wind pressure difference coefficient is not significant. © 2014 Elsevier Ltd.
Liu W.,South China Normal University |
Hou Q.,Shenzhen Institute of Building Research Co. |
Hou Q.,Hong Kong Baptist University
Chinese Geographical Science | Year: 2015
During the reform era, Chinese cities witnessed dramatic institutional transformation and spatial restructuring in general and profound change of commuting patterns in particular. Using household surveys collected in Guangzhou, China, in 2001, 2005 and 2010, excess commuting measurements are estimated. Excess commuting shows an overall trend of increasing during 1990–1999, and then declining during 2000–2010. We argue that deepening marketization of the jobs and housing sectors has induced spatial separation of jobs and housing. In other words, institutional transition and urban spatial restructuring are underpinning the changes of commuting patterns in Chinese cities. Excess commuting has strong relationship with individual socio-demographic status, which is by and large due to the increasing flexibilities of jobs and housing location choices enjoyed by urban residents. The findings call for considerations on balancing jobs-housing in making public policies relevant to urban development in general, and land use and transportation in particular. © 2015 Science Press, Northeast Institute of Geography and Agricultural Ecology, CAS and Springer-Verlag Berlin Heidelberg
Ma S.,Southwest Jiaotong University |
Zhou Q.,Shenzhen Institute of Building Research Co.
ICLEM 2012: Logistics for Sustained Economic Development - Technology and Management for Efficiency - Proceedings of the 2012 International Conference of Logistics Engineering and Management | Year: 2012
Based on China railway freight volume statistics from 1978 to 2010, this paper analyzes railway freight time series' numeral characteristic with the using of econometrics method. According to freight time series unit root test, prove that freight time series is a two-order fractional integration serial. Observing the residual of freight time series after two differences the paper got autocorrelation and partial autocorrelation, then established China railway freight volume ARIMA forecasting model. Through testing the forecasting modal, it was found that the result is satisfactory. Finally, the paper forecasts the railway freight volume of 2012 and 2013 and the precision is high. © 2012 American Society of Civil Engineers.
Lin Y.,Fudan University |
Fotios S.,University of Sheffield |
Wei M.,Pennsylvania State University |
Liu Y.,Shenzhen Institute of Building Research Co. |
And 2 more authors.
Investigative Ophthalmology and Visual Science | Year: 2015
PURPOSE. Involuntary physiological responses offer an alternative means to psychophysical procedures for objectively evaluating discomfort glare. This study examined eye movement and pupil size responses to glare discomfort using new approaches to analysis: relative pupil size and speed of eye movement.METHODS. Participants evaluated glare discomfort using the standard de Boer rating scale under various conditions manipulated to influence glare discomfort. Eye movement was recorded using an electro-oculogram (EOG), and pupil size was recorded using Tobii glasses. Ten young (mean age: 24.5 years old) and 10 senior (mean age: 61 years old) participants were recruited for this experiment.RESULTS. Subjective evaluation of glare discomfort was highly correlated with eye movement (multiple correlation coefficient [R2] of >0.94, P < 0.001) and pupil constriction (R2 ¼ 0.38, P<0.001).Severeglarediscomfortincreasedthespeedofeyemovementandcausedlarger pupil constriction. Larger variations of eye movement were found among seniors.CONCLUSIONS. The two physiological responses studied here to characterize discomfort glare under various lighting conditions had significant correlation with the subjective evaluation. The correlation between discomfort glare and physiological responses suggests an objective way to characterize and evaluate discomfort glare that may overcome the problems of conventional subjective evaluation. It also offers an explanation as to why long-term exposure to discomfort glare leads to visual fatigue and eyestrain. © 2015 The Association for Research in Vision and Ophthalmology, Inc.
Qin M.,Nanjing University |
Yang J.,Nanjing University |
Yang J.,Shenzhen Institute of Building Research Co.
Building Simulation | Year: 2016
Building energy simulation is essential for most architectural design projects. Many models have been developed to predict the indoor air temperature and relative humidity as well as the building’s heating and cooling loads. However, in most building energy analysis the calculation of heat conduction through walls usually neglects the transport and storage of moisture in porous building materials, and the interaction between hygrothermal transfer and airflow inside the building. An accurate heat load (both sensible and latent load) determination requires a calculation of the coupled heat and moisture transfer in building envelopes and the hygrothermal interactions between the envelope and the environment. This paper evaluates the accuracy and the applicability of three thermal models in EnergyPlus (CTF—Conduction Transfer Function model, HAMT—Combined Heat and Moisture Transfer model, EMPD—Effective Moisture Penetration Depth model) for calculating moisture effects on building energy consumption in different climate conditions. The simulation results are compared with field measurements. The effects of different room infiltration rate on the accuracy of different models are also analyzed. © 2015, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.
Shi Y.,Nanjing University |
Shi Y.,Shenzhen Institute of Building Research Co. |
Sun X.,Nanjing University |
Zhu X.,Nanjing University |
And 2 more authors.
Landscape and Urban Planning | Year: 2012
Peri-urban areas are sites currently experiencing the most active urbanization. In order to quantify the complexity in urban growth patterns and processes, based on the common boundary and Landscape Expansion Index (LEI) analysis, we developed six spatial rules to identify three urban growth types of infilling, edge-expansion and outlying in 2000-2008. In addition, growth density (GD) with buffer zone analysis was applied to ascertain urban movement from the city center. Results indicated the prominent urban growth type was edge-expansion, with continued urbanization most prominently in the peri-urban areas. The infilling growth increment proportion in the second study period (2004-2008) suggested the study area was experiencing an increased coalescence pattern and declined diffusion pattern. However, the highest infilling GD zones that occurred primarily near the city center did not vary significantly in 2000-2008. The intensive urban growth zones in the first study period (2000-2004) followed by later efficient infill growth also suggested urban growth was more compact in the second study period. Furthermore, two land use change maps showed that substantial arable land was lost by urban growth in 2000-2008, and the establishment of industrial parks encroached on large salt marsh in the second study period. Further research is required to delineate a suitable development management plan to sustain a baseline for urban growth. Furthermore, the integration of a zoning approach associated with the green belt is suggested to play a key role in a transition to continued urbanization. © 2012 Elsevier B.V.
Liu C.,Shenzhen Institute of Building Research Co. |
Liu C.,University of Auckland |
O'Sullivan D.,University of California at Berkeley
Computers, Environment and Urban Systems | Year: 2016
The paper describes a simple, abstract model to simulate gentrification from both supply and demand side perspectives. Three theories-rent gap theory, filtering theory and household life cycle theory-are employed to construct a combined cellular automaton and agent-based model. This abstract model has good potential for simulating urban development. It exhibits a distinctive relationship between the spatial dynamics of gentrification patterns and different rent gap thresholds and rent gap impacts: at low rent gap thresholds and limited rent gap impact, renovation events occur at all locations leading to a mixed rent map distribution. As the rent gap threshold and rent gap impact increase, gentrification becomes more spatially concentrated, leading to spatially segregated rent patterns. Also, gentrification starts in run-down areas neighboring wealthier regions in agreement with empirically observed gentrification. © 2016 Elsevier Ltd.
Zhang Y.,South China University of Technology |
Liu Q.,Shenzhen Institute of Building Research Co. |
Meng Q.,South China University of Technology
Building and Environment | Year: 2015
Airflow utilization is a traditional and effective way for people to improve their thermal comfort in summer in the areas of China that are hot and humid. We conducted a summer-long field study on nine naturally ventilated buildings in Guangzhou and collected airflow-related behaviors, motivations, and perceptions from 32 college students. The results show that the behaviors of opening windows and doors were driven by both indoor air quality and thermal comfort motivations. The proportions of open windows and doors increased linearly and slowly with the indoor ET*, and the acceptable range for opening windows and doors was an indoor ET* ≤30.3°C with the condition that a maximum of 0.25m/s indoor air speed needs to be achieved. The behaviors of using fans were driven by thermal comfort motivations. The proportions of use of fans increased strongly with the indoor ET*, and the acceptable range for using fans was an indoor ET* ≤31.0°C with the condition that a maximum of 0.87m/s indoor air speed needs to be achieved. A strategy for airflow utilization was proposed. Our study is believed to provide a better understanding of airflow-related behaviors, motivations, and perceptions as well as better designs of natural ventilation and fans and better simulations of performance for buildings in the hot and humid areas of China. © 2015 Elsevier Ltd.