At present, the thermal comfort evaluation index has not been differentiated for different types of people, and the indoor thermal environment of the residences in rural areas of cold climate, China, urgently need attention. In this study, indoor living environment of rural residences in Hebei and Tianjin were measured to obtain typical residential forms, building thermal parameters and thermal comfort parameters of the elderly. At the same time, 152 elderly people were investigated by questionnaire to obtain the subjective evaluation such as thermal sensation. In addition, the optimization suggestions of plane structure, building envelope and window to wall ratio were put forward through software simulation. The results show that the thermal neutral temperature of the rural elderly people in cold zone is 16.74°C, and they are more sensitive to the temperature below 15.67°C and more slowly to the temperature above 15.67°C. The recommended thickness of wall insulation layer is 80–100 mm, and that of roof insulation layer is 60–80 mm. Double layer glass should be used. Wood window frame has better thermal insulation effect than aluminium frame, and the recommended window to wall ratio is 0.28.

The imbalance of rural parking supply and demand has a great impact on traffic congestion and environmental pollution, which has attracted the attention of many scholars as well as policymakers. However, most of the current research on parking choice focuses on urban business and residential areas rather than on rural parking choice behaviour, and focuses on the analysis of observable factors, ignoring the internal relationship with potential variables. This study considers the heterogeneity of individuals and uses the random forest (RF) algorithm to construct a model of rural residents’ willingness to choose parking with both latent and explicit variables, to explore how much and in what ways individual characteristics and parking characteristics affect rural residents’ parking choices, and to explore parking planning programmes and strategies that are truly applicable to rural areas. The results of the study suggest that the safety and convenience of the parking environment are key factors influencing the parking choice behaviour of rural residents, and can greatly improve the predictive accuracy of the parking willingness model. Upon comparison, it is found that the application of the RF algorithm is also significantly better than the logit model in terms of prediction effect, indicating that there is a nonlinear effect among the factors influencing the parking choice behaviour of rural residents and that the RF model with the addition of latent variables provides a better explanatory ability for the study of the parking choice behaviour of rural residents.

To reduce the carbon emissions of existing residential buildings while pursuing maximum cost benefits, a multi-optimization design method for the existing residential building rooftops, retrofitted by attaching the solar photovoltaic panels and thermal collectors, was proposed in the study. At first, the life cycle carbon emission and cost benefit of the retrofitted buildings were assigned as the optimization objectives, and the models of carbon emission and cost benefit were developed. Furthermore, a typical existing residential community located in the cold zone of China was selected to perform the multi-optimization based on the Grasshopper platform. Meanwhile, the laying area, laying angle, and allocation ratio of the solar photovoltaic panels and thermal collectors were selected as the design parameters. And then the best retrofitting solution suitable for the existing residential buildings was proposed. The results show that the weightings of the carbon emission of retrofitting life cycle are 42.68%, and that for the cost benefit is 57.32%. Significantly, there is a 31% reduction in carbon emissions compared to the building before retrofitting, and a 24.7% reduction in cost benefit.

Incorporating sufficient daylight is an effective and green design strategy to improve visual comfort, energy-efficiency and sustainable building developments. However, there are more artificial lighting consumption, more cooling load and less visual comfort in internal corridors of most buildings due to the shortage of daylight. In this paper, three methods comprising questionnaire survey, numerical simulation and field measurement were integrated to study the daylighting characteristics and the critical length of the corridor with an end window or an open room in daylighting design. It began with a questionnaire survey to understand the subjective perception of the building's users on the lighting status, daylighting importance and daylighting preference in the internal corridor. Then the daylighting performance of the building corridors with the end window and the open room was simulated by Ecotect, and the analysis of the simulation data was performed through SPSS. Two models were developed for predicting the daylighting critical length of the corridors. Furthermore, a comparison of the field measurement data and the predicted results was carried out to validate the models. The results indicated that the developed models have the better accuracy and can be referred to as a guide for the initial daylighting design of buildings.

Objective. Large-scale studies on the characteristics and management of abdominal trauma in megacities in China are lacking. The aim of this study was to analyze and present the clinical patterns and treatment status of abdominal trauma in regional medical centers. Methods. Cases of abdominal trauma treated at seven medical centers in Beijing from 2010 to 2021 were collected. Clinical information about age, sex, injury cause, geographic distribution, abbreviated injury scale/injury severity score (AIS/ISS) value, injury-hospital time, preoperative time, surgically identified organ injuries, type of surgery, causes of reoperation and 90-day mortality was included in this study. Clinical characteristics, treatment methods, and short-term prognoses (90-days survival) were compared between blunt abdominal trauma (BAT) and penetrating abdominal trauma (PAT) cases. Non-normally distributed data are described as medians (IQR), and the Mann-Whitney U test was performed; qualitative data were analyzed using the X2 test. Univariate and multivariate survival analyses were performed by the Cox proportional hazards model. Results. A total of 553 patients (86.98% male) with a median age of 36.50 (27.00-48.00) years were included. The BAT group had a significantly higher proportion of serious injury (P=0.001), lower initial hemoglobin level (P=0.001), and a lower laparoscopy surgery rate (P=0.044) compared to the PAT group. Additionally, more BAT cases were from the area around Beijing (P=0.008) and a longer injury-regional hospital time (10.47 (5.18-22.51) hours vs. 7.00 (3.80-15.38) hours, P=0.001). In the hollow viscus injury subgroup, the BAT group had a significantly longer injury-regional hospital time and preoperative time compared to the PAT group (injury-regional hospital time: 10.23 (6.00-21.59) hours vs. 7.07 (3.99-13.85) hours, P=0.002; preoperative time: 3.02 (2.01-5.58) hours vs. 2.81 (1.85-3.63) hours, P=0.047). The overall 90-day mortality was 11.9%, and longer injury-regional hospital time (HR: 1.01, 95% CI: 1.00-1.02, P=0.008), receipt of ICU treatment (HR: 4.69, 95% CI: 2.54-8.65, P=0.001), and severe ISSs (ISS > 25 vs. ISS < 16, HR: 2.78, 95% CI: 1.38-5.601, P=0.004) had a worse impact on survival. Conclusion. More patients with BAT were transferred to higher-level hospital, leading to significantly longer prehospital and preoperation time. In the subgroup of hemodynamically stable individuals, more patients with BAT experienced hollow viscus injuries. For those patients, aggressive diagnostic laparoscopic exploration may be beneficial. Patients with longer injury-regional hospital intervals, the need for ICU care, and higher injury severity scores (ISSs) suffered from worse prognoses.

The twin screw expander, applied to a power generation system for recovering waste pressure energy of natural gas (NG), is reliable. It has lower capital costs and maintenance performance compared to the others. In this paper, a computational procedure based on the Benedict-Webb-Rubin (BWR) equation is established. Meanwhile, the experiment is carried out to study the performance of a twin screw expander prototype. The results shows that the twin screw expander has an optimum rotational speed where the specific shaft work, efficiency reach their peaks when delivered a certain gas, and the optimum rotational speed reduces with the decrease of the inlet pressure.