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As an innovative ventilation mode, attached ventilation has been widely used in different types of buildings due to its high ventilation efficiency and energy saving. At present, the commonly used air outlet form is slot outlet. Considering the diversity of application places, different air outlet form models (Slot outlet (SO), Rectangular outlet (RO), Circular outlet (CO), Semi-circular outlet (SCO)) were established in this paper. Air distributions of the attached ventilation under different air outlet forms are analyzed and compared. The results show that the attached jet thickness is larger under RO, CO, and SCO form. Compared with SO form, the jet velocities of other three forms decay slowly in the vertical region. The attached ventilation with different outlet forms can form an "air lake" in the occupied zone to ensure the comfort environment. This research provides design references for the design and application of the attached ventilation under different air outlet forms.

With the rapid development of greenhouses, the indoor air quality, particularly airborne microorganisms, is closely related to the health of farmers and needs more attention. In this study, the concentrations of airborne fungi at seedling, fruiting and harvesting stages in typical tomatoes greenhouses were tested. Temperature, relative humidity and the microbial concentrations were analysed. It was found that the dominant fungal genera are Aspergillus and Cladosporium, no matter it was in which growth stage. Ventilation is an effective way to reduce the concentrations of airborne fungi through dilution and decrease the relative humidity.

Energy piles and ground source heat pump systems have been shown to provide sustainable alternatives for temperature regulation in buildings and other applications such as road de-icing. However, their efficiency can be undermined in partially-saturated and dry sandy soils due to the relatively low thermal conductivity (kt) of these materials. Microbially-Induced Calcite Precipitation (MICP) has been demonstrated to be an environmentally-conscious ground improvement technology capable of modifying the engineering properties of sandy soils including increases in shear stiffness and strength and decreases in hydraulic conductivity. These improvements result from the precipitation of calcium carbonate crystals at inter-particle contacts and on particle surfaces. This paper presents results from a soil column study aimed at investigating changes in soil kt during MICP treatments and subsequent desaturation using a poorly- graded sand. The results indicate that while bio-cementation can increase soil kt, the level of enhancement depends on the degree of saturation. For instance, increases of up to 330% were measured under dry conditions while only modest increases of about 15% were measured under saturated conditions. MICP treatment may therefore be most effective at enhancing the kt of partially-saturated and dry sands. In addition, the similarity between the evolution of kt and shear wave velocity (Vs) during MICP treatment suggests that kt may provide a new method to assess cementation level and contact quality.

In order to analyze the mechanical behavior of surrounding rock and initial support during shaft excavation and support process, reveal the law of stratum displacement, the stress characteristics of surrounding rock and the internal force of supporting structure during construction, this paper establishes a three-dimensional finite element numerical model relying on the construction process of a ventilation shaft in Chongqing Rail Transit. The results show that the stress of shotcrete, the bending moment of supporting structure, the axial force of bolt and the axial force of I-beam are all within the allowable range. The "S" shape bending occurs in the range of 60m~70m for the axial force of bolt and cross brace I-beam. According to the results of model test, there is inflection point in the pressure distribution of rectangular deep ventilation shaft in rail transit, which provides a basis for the support design of deep ventilation shaft.

Lake Qarhan is the largest salt lake and potassium salt resource mining base in china. Understanding the origin of brines and the contribution of modern water circulation is extremely important to the sustainable development of the salt lake. Comprehensive tools including isotope, hydrochemistry and numerical simulation had been performed. Results suggest that brine groundwater in the salt lake area is the result of ancient brines migrated from the western Qaidam Basin due to the uplift of the western basin in the geological past. Shallow phreatic aquifers in the salt lake area are also recharged by the modern surface water in the flood period. The contribution of modern groundwater circulation to the salt lake area is very limited with only 3% of the total quantity of groundwater discharge for the watershed.

In this study, stability against deep sliding of gravity dam is analysed in order to provide guidance for ensuring stability against sliding of gravity dam during the construction and operation periods. Based on checking-point method (JC method), the study proposes an analysis model for stability against deep sliding of gravity dams. In addition, the rigid body limit equilibrium method is utilized to construct the limit state function of deep anti-sliding stability. With sliding plane anti-shear friction coefficient and anti-shear cohesion calculated as random variables, safety degree of stability against deep sliding is analysed. With JC method employed, the calculation program is compiled to calculate the stability against deep sliding of gravity dam and analyse the non-overflow section of gravity dam under normal storage level. According to calculation program, the reliability index β of stability against deep sliding of gravity dam is 4.36, and the failure risk Pf is approximately zero. Additionally, based on the traditional rigid body limit equilibrium method, the safety factor K is 3.23, which meets the requirements of the design specification. According to the above methods, stability against deep sliding of the dam section meets the requirement. In conclusion, JC method provides a calculation and analysis model for gravity dam’s stability against deep sliding, serving as references in the design of gravity dams based on reliability theory.

Most existing temperature field calculation programs have relative defects. In the present paper, based on merits of ANSYS platform, a temperature field calculation program of mass concrete structure is developed and demonstrated. According to actual pouring progress and thermodynamic parameters, a roller-compacted concrete dam is simulated. The difference of maximum temperature between calculated and measured values of measuring points is less than 1.8°C. Furthermore, the relative difference is -5%–5%. This result shows that the calculation program developed based on ANSYS platform can simulate and calculate the temperature field of mass concrete structure.

In the safety area of industrial production, robots are required to have the ability of quickly detecting the dynamic obstacles which appear in the working space of robots when robots move along a predefined route. In order to solve the problem of dynamic obstacles detection more effectively, the paper proposes a quick detection method based on background compensation for dynamic obstacles in robot movement space, which makes extraction of feature points on dynamic obstacles in robot movement space, establishes the background model of optical flow velocity field between adjacent frames and makes background compensation for images with the use of block-matching algorithm in order to realize quick and accurate dynamic obstacles detection in dynamic environment. The experiment results show that the obstacles detection method can effectively eliminate the background movement caused by the movement of camera at the end of robot and can extract a more complete target object. Moreover, it also has good robustness.

The purpose of this research is to develop a method that measures a torque which an operator applies to the joystick without using a torque/force sensor on a joystick. We dealt with a construction robot teleoperation system which is comprised of two joysticks as the master, and an excavator with four degrees of freedom consisting of fork glove, swing, boom, and arm as the slave. It is necessary to know the torque (force) exerted on the master side in force control. Because the joystick does not have a force/torque sensor in our lab, it is not possible to directly obtain the torque. To give prominence to the simple and practical construction robot teleoperation system in our lab, we proposed a method that measures the torque exerted on the joystick to existing equipment. Its effectiveness was verified by a reaction torque experiment.

Traffic sign detection and recognition has been the active research topic due to its potential applications in intelligent transportation. However, detection and recognition of traffic panels containing much information, still remains to be a challenging problem. This paper proposes a method to detect and recognize traffic panels from street-level images in the urban scenes and to analyze the information on them. The traffic panels are detected based on histogram of oriented gradient and linear support vector machines. The text strings and symbols on traffic panels are segmented using connected component analysis method. Finally, the symbols on traffic panels are recognized by means of a model named bag of spatial visual words. Experimental results on images from Baidu Panorama Map prove the effectiveness of the proposed method.