Combined effects of the thermal-acoustic environment on subjective evaluations in urban squares

Because human beings live in an environment in which various factors interact, it is necessary to study the effects of these factors on environmental evaluations. This study employs a questionnaire survey to explore the effects of the thermal-acoustic environment in urban squares on subjective evaluations (thermal evaluations, acoustic evaluations, and overall comfort) in severe cold regions. It also evaluates and predicts equivalent overall comfort under different conditions of the thermal-acoustic environment. The results indicate that with respect to thermal evaluations, a higher temperature causes a significant increase in thermal sensation in all the three seasons (summer, the transitional season, and winter) while traffic noise causes a slight increase in thermal sensation only in summer. Meanwhile, both temperature and traffic noise affect thermal comfort in all three seasons, with higher traffic noise causing lower thermal comfort. With respect to acoustic evaluations, higher traffic noise results in a more negative evaluation of subjective loudness and acoustic comfort, while the low temperature in winter and high temperature in summer increase acoustic discomfort. However, the interaction of temperature and traffic noise has an effect on acoustic comfort only in summer. In addition, temperature significantly affects overall comfort in all three seasons, while traffic noise has an effect only in the transitional season and summer; however, their interaction affects overall comfort only in winter

Analysis of Thermal Environment of Open Community Streets in Winter in Northern China

The long winter time and the harsh outdoor environment cause many inconveniences of the outdoor activities to urban residents in severe cold areas. Therefore, it is urgent to study and improve the thermal environment in urban residential streets. This paper focuses on winter thermal environment of streets in open communities of northern China, by carrying out field measurements according to the characteristics of cold climate and urban residential areas. The results show that the aspect ratios of streets can directly affect their thermal environment. With the aspect ratio increases, the air temperature decreases and the wind speed increases. At the same time, facade openings can make the average globe temperature significantly increased in the streets. This paper provides basic data for the further study of thermal environment in urban streets and the optimization design of street spaces

A Review of Green Building Development in China from the Perspective of Energy Saving

This paper reviews the history of green building development and assessment standards in China, particularly from the perspective of energy saving. It is divided into four parts: (1) the development of policies of green building in China that have been proposed for meeting energy-conservation and emission-reduction targets; (2) the scientific research on green building by the Chinese government, including the promotion of maximum resource sustainability, environmental protection, and the reduction of pollution; (3) the development of assessment standards for green building in China; and (4) the development of green building technologies in China

Field study on the influence of spatial and environmental characteristics on the evaluation of subjective loudness and acoustic comfort in underground shopping streets

A large-scale measurement and subjective survey was undertaken in five underground shopping streets to determine the influence of spatial and environmental characteristics on users’ subjective loudness and acoustic comfort. The analysis on the spatial characteristics shows that the subjective loudness is higher in “street type” than in “square type” underground shopping streets when the equivalent continuous A-weighted sound pressure level (LAeq) is relatively high (75 dBA). Acoustic comfort is higher in “square type” than in “street type” underground shopping streets where LAeq is relatively low (55 dBA). Considering spatial functions, it is found that acoustic comfort is higher in a dining area than in a shopping area. In terms of environmental characteristics where air temperature, relative humidity, luminance and visual aspect were considered, the subjective loudness is influenced by humidity and luminance, with correlation coefficients of 0.10 to 0.30. The evaluation of acoustic comfort is influenced by air temperature, humidity, and luminance, with correlation coefficients of 0.1 to 0.4. There are significant correlations between the evaluation of environmental factors and subjective loudness, as well as, acoustic comfort. The correlation coefficients are 0.1 to 0.5. Moreover, respondents’ attitude to sound environment could influence their evaluation of subjective loudness and acoustic comfort

Effects of individual sound sources on the subjective loudness and acoustic comfort in underground shopping streets

Previous studies have demonstrated that human evaluation of subjective loudness and acoustic comfort depends on a series of factors in a particular situation rather than only on sound pressure levels. In the present study, a large-scale subjective survey has been undertaken on underground shopping streets in Harbin, China, to determine how individual sound sources influence subjective loudness and acoustic comfort evaluation. Based on the analysis of case study results, it has been shown that all individual sound sources can increase subjective loudness to a certain degree. However, their levels of influence on acoustic comfort are different. Background music and the public address system can increase acoustic comfort, with a mean difference of 0.18 to 0.32 and 0.21 to 0.27, respectively, where a five-point bipolar category scale is used. Music from shops and vendor shouts can decrease acoustic comfort, with a mean difference of -0.11 to -0.38 and -0.39 to -0.62, respectively. The feasibility of improving acoustic comfort by changing certain sound sources is thus demonstrated

Effects of sound types and sound levels on subjective environmental evaluations in different seasons

Human beings live in an environment where various factors act together, therefore, it is essential to study the comprehensive effects of multiple factors, particularly the effects of their interaction on environmental evaluations. In this study, the effects of the interaction between sound types and sound levels on acoustic, thermal, and overall evaluations were explored by simulating typical outdoor temperatures in different seasons in a controllable environmental chamber. The results indicated that the acoustic evaluations were significantly higher for birdsong and slow-dance music than for dog barking, conversation, and traffic sound; additionally, the acoustic evaluations at the low sound level were always higher than those at the high sound level. In terms of the thermal evaluations, there was a significant variation in different seasons. In summer, birdsong and slow-dance music effectively improved subjects’ thermal evaluations, while a high sound level of dog barking, conversation, and traffic sound resulted in a decrease; in the transition season, all types of sounds resulted in a decline in the thermal evaluations; meanwhile, in winter and summer, dog barking, conversation, traffic sound and slow-dance music at the low sound level produced higher thermal comfort and thermal acceptability. In terms of the overall evaluations, birdsong and slow-dance music at the low sound level improved overall comfort, while dog barking, conversation, and traffic sound resulted in a significant decrease. For dog barking, conversation, traffic sound and fast-dance music, the overall evaluations at the low sound level were higher than those at the high sound level

Identification of Independent Variables to Assess Green-Building Development in China Based on Grounded Theory

BACKGROUND: Development of green building as future buildings has become a trend and played a significant role in changing the general direction of building development and creating an environment for sustainable development ’People-centric’ explores the relationship between people and building development. From the perspective of users, what are the influencing factors of green building? What is the relationship between independent variables? The authors link this issue to the development of green building and gaining a clearer understanding and direction. METHODS: The authors applied grounded theory and intensity sampling to analyse the relationships of independent variables. RESULTS: he findings of this study reveal the four core factors affecting how independent variables get to learn about green building, which are ‘personal perception elements’, ‘social elements’, ‘organisational elements’, and ‘architectural properties’. CONCLUSIONS: The authors also analysed the relationships between the independent variables to explore construction theory for helping green building better respond to people’s demand and pushing forward its development. In this case, the ’people-centric’ green building further improves the urban living environment

Effects of geometry on the sound field in atria

© 2017, Tsinghua University Press and Springer-Verlag Berlin Heidelberg. The atria in commercial buildings are widespread. However, the sound environment has not been given sufficient consideration. Geometry affects the acoustics in the atria. The concept of geometry in this paper includes five parameters, namely, length (l), height (h), aspect ratio of length to width (l/w), skylight form and slope, to provide suggestions for the acoustic environment design in atria. A series of computer models are simulated to analyse the effects of the form parameters on the acoustic environment, such as sound pressure level (SPL) and reverberation time (T30 in this paper). The results indicate that with an increase in the length or height, the values of the average SPL decrease, and the trends of the curves are logarithmic. For an increasing length, the T30 increases first sharply and then slowly. With the scattering increasing, the increment of the T30 is smaller. For an increasing height, the changes of T30 are determined by the absorption and scattering. In terms of the aspect ratio of l/w increasing for a given volume and area, the average SPL values approximately decrease linearly; furthermore, the T30 decreases unless the atrium is extremely high. The T30 is the longest for a flat skylight compared to that of other forms, and it is shorter when the skylight has a slope, including either a single or a double-pitch skylight. It can decrease nearly by 40% when the angle of the lean-to skylight is 7°. The T30 is lower and the amount of decrease is considerably smaller for an increasing slope. When the absorption is evenly distributed in the atria, the skylight has minimal effect on the average SPL or T30 values. Additionally, the classical formula can approximately calculate the SPL distribution unless the atrium is in a form of long space. The Arau-Purchades formula is generally appropriate to predict T30 with uneven absorption distributions unless the absorption or scattering coefficient is low

Amorphous metallizations for high-temperature semiconductor device applications

The initial results of work on a class of semiconductor metallizations which appear to hold promise as primary metallizations and diffusion barriers for high temperature device applications are presented. These metallizations consist of sputter-deposited films of high T sub g amorphous-metal alloys which (primarily because of the absence of grain boundaries) exhibit exceptionally good corrosion-resistance and low diffusion coefficients. Amorphous films of the alloys Ni-Nb, Ni-Mo, W-Si, and Mo-Si were deposited on Si, GaAs, GaP, and various insulating substrates. The films adhere extremely well to the substrates and remain amorphous during thermal cycling to at least 500 C. Rutherford backscattering and Auger electron spectroscopy measurements indicate atomic diffussivities in the 10 to the -19th power sq cm/S range at 450 C

The effects of residential area building layout on outdoor wind environment at the pedestrian level in severe cold regions of China

In recent years, there has been a frequent occurrence of extremely cold conditions which has had a serious impact on the life of residents of buildings in various locations around the world. However, there have only been a very limited number of studies on the effects of residential area building layout on the winter wind environments, which led to a lack of quantitative guidance for residential area planning in severely cold regions. This study aims to reveal the relationship between (1) the residential areas' building density, floor area ratio, wind projection angle, average building height, and relative position of high-rise buildings, and; (2) the mean wind velocity ratio at pedestrian level in severe cold regions. In this study, the pedestrian-level outdoor wind environments in 24 typical residential areas of Harbin, China, are simulated using ENVI-met software. The results show that the relative position of high-rise buildings in multi-high-level mixed residential areas has little influence on the mean wind velocity ratio, and the maximum difference is 0.04. The factors of building layout have little influence on the mean wind velocity ratio of multistory residential areas. However, a significant linear correlation exists between the mean wind velocity ratio of high-rise residential areas and both the building density and wind projection angle. The prediction model of the mean pedestrian-level wind velocity ratio was then established