Regenerative cooling is being used to meet the high requirements of advanced hypersonic flight vehicles using fuel at supercritical pressures as coolant. The heat transfer and thermal cracking characteristics vary with pressure, mass flow rate flux. This work presents an experimental investigation pressure hydrocarbon fuels their interactions. A proportional production distribution chemical model was developed for pre-exponential factor activation energy describe reactions. Numerical results...

A small amount of research has been conducted in dealing with pavement shadow–affected cracks detection. Hence, this aims to develop the illumination compensation model (ICM) and k-means clustering algorithm–based crack detection considering influence shadows. First, shadow area was divided into umbra penumbra according mechanism. Then, removal methods for different areas were analyzed separately. Since intensity changes homogeneously, ICM approach can be a convenient way removal. While...

To address the low thermal conductivity of phase change materials and e improve heat storage, a novel rotating T-LHTESU structure is proposed. Numerical simulations systematically analyze effects rotation speed, various eccentricities wall temperature on performance storage. The results show that introduction in intermediate sleeve shortens melting time with increasing reaching maximum reduction 61.66 % at 2 rps. Furthermore, rate 1 rps 2rps first decreases then increases eccentricity. At an...

Transpiration cooling technology is a feasible thermal protection method for hypersonic vehicles. To ensure the safety of transpiration structures, coke deposition rule hydrocarbon fuels in porous media key problem that has to be considered. In this paper, experimental studies are reported on n-decane and HF-II fuel sintered bronze at different pressures temperature ranging from 350 638 °C. Results showed was dominant factor generation fuels. Two types coking behaviors, i.e.,...

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is spreading globally, and its high transmission speed mortality rate are severely interfering with people’s normal lives the economy. Governments now reopening their economies; however, opening of theaters has been delayed, owing to (often) crowded audiences potentially higher infection risk. To determine whether it safe reopen theaters, in this study, transport contaminants released by an infected person a theater hall overhead...

Air-conditioning (AC) is discontinuously used in Shanghai residential buildings during the winter time. The AC usage pattern, therefore, has great influence on its energy consumption. In order to figure out space heating consumption for residents, it's necessary have an accurate description of model. this study, questionnaire surveys and continuous measurements 10 residents were done Shanghai. Based Marcov Chain conditional probability model, descriptive parameters under three different...

This paper aims to achieve the accurate detection of ball grid array (BGA) solder joints.To this end, author presented an adaptive template matching method for BGA joints based on shape detection.First, region interest (ROI) was selected from X-ray image printed circuit board (PCB).Then, edge generated through ROI extraction and threshold segmentation, direction vector f taken as prior knowledge.After that, global traversal search performed pyramid in top-down manner, aiming obtain potential...

Pipe-embedded double-skin façades (PDSFs) have proved to be among the best approaches solve overheating problem confronted in conventional (DSFs). Although heat transfer characteristics of PDSF been investigated by numerical methods previous research, free-running temperature and economic operating strategy a room with not studied. In this study, prediction method for equipped is established. The performance different types rooms under strategies Guangzhou was obtained. results show that (1)...

Abstract In order to better understand the flight performance and kinematics of flapping wing aircraft designed developed based on principle bionics, a space crank rocker mechanism was tried carry out virtual prototype design bionic in motion, this basis, its movement characteristics were analyzed. Analyzing mechanisms scale laws common flying organisms yields various physical estimation parameters that affect characteristics. Flight patterns motion are analyzed principles seabirds,...

Pipe-embedded windows can significantly reduce the cooling/heating load of buildings when integrated with low-grade energy. However, studies on reduction effect under different climates remain insufficient, and optimal location double-glazing glass width air interlayer have not been studied. Thus, in this study, performance a pipe-embedded window water temperatures representative structures is investigated numerically. According to simulation, linear relationship found between climatic...

This paper will analysis the energy-saving situation for urban village building envelope structure such as wall, windows, roofs and others according economic conditions climate characteristics of northwestern Henan province, put forward suitable designing ideas measures about exterior-protected structure, provide a basic research designing.

Clean energy can directly generate electricity for production and life.It does not emit pollutants, has low carbon characteristics, conforms to the requirements of United Nations Framework Convention on Climate Change.Therefore, its power generation is increasing, which caused problem that it cannot be absorbed by users.This paper analyzes current research situation clean consumption, studies two main factors affect scenario namely consumption measures system flexibility supporting...

Pipe-embedded double skin facade, which arranges pipes in shading device, is an alternative to reduce indoor demand and save energy. To simulate annual performance of this system, a simplified approach based on optical thermal property proposed at first, dynamic acquired through state-space method. Then the model validated with former investigation shows good accuracy. Indoor room temperature pipe-embedded façade analyzed under different types Guangzhou last. Results show that could...

Background: Whether the new adjusted family planning policy in China affected fertility and health-related problems including advanced maternal age caesarean delivery has not been well addressed.