Advanced Materials Research Vol. 908

Abstract: In order to avoid the jamming problem of drill-rod because of slow response of existing drilling equipment when facing gaps and karst caves during drilling process, we proposed the principle scheme of a quick-response hydraulic control system which aimed at making the jackdrill return as soon as possible once detected gaps and karst caves. The model of the hydraulic system was established and then solved by AMEsim. The parameters of critical parts such as restrictors and anti-jamming group valve were optimized by simulating to achieving the shortest theoretical response time. The system has been applied to field experiment and the result shows its ascendant ability of preventing jamming failure,the response time is shorter than traditional system in half. This research has great engineering application value to improve the drilling efficiency.

Abstract: According to the working principle of open hydraulic system in concrete pump, and though the theoretical analysis on the phenomenon of hydraulic impact in direction changing process, it concluded that the impact pressure has a linear relation with the displacement of the main oil pump .To solve the hydraulic impact problem ,a variable displacement method was proposed .Under the requirement of piston not striking the bottom of cylinder and piston stroke control accuracy ,the authors optimized the pumping direction changing process time parameters and the displacement control time parameters . Though the AMESim modeling simulation and experimental study , the variable displacement control method is proved feasible on reducing the hydraulic impact in direction changing process.

Abstract: This paper use the Friuli Siegel formula for calculating the main steam flow. Analyzed the difference between using different stage pressure to calculate the main steam flow and the tested main steam flow. Other stages pressure that using for calculating the main steam flow can be used for comparative analysis.

Abstract: Feeding pressures control of hydraulic drilling rig is a critical technology of drilling quality. In order to control feeding pressure accurately during hydraulic drilling rigs working, A new feeding system was proposed, based on the cartridge valve controlled by high speed on/off valve. Feeding pressure was exported proportionally via control of high speed on/off valves input PWM signal. Its model was built by AMESim software, to analyze characteristics of the cartridge valve and research the feeding systems response to pressure-commanded signal. The results show that the feeding pressure can be regulated proportionally and the control performance of the feeding pressure can be improved by increasing moderately PWM signals frequency, which provides a reliable reference for further optimization of hydraulic system of drilling rig.

Abstract: The buffer device of hydraulic piling hammer is a power source coupling the thermodynamic , mechanical and hydraulic domains. Traditional modeling techniques usually focus on the single-domain systems. Equations of multi-energy domains must be connected by the intermediate variables , but the complexity o f thermodynamic dynamics restricts this modeling method. In th is paper, bond graph model of the buffer system including multi-energy domains was developed in a unified way, the dynamic simulation was studied and the experimental results validate the modeling method.

Abstract: During the process of grid structure lifting, the bearing capacity of some bars may overrun, because lifting point bears the main gravity of whole grid structure and the overall stress of grid structure changes ^[1]. Taking a steel grid structure lifting project as an example, this thesis analyzes the bearing capacity and stability of bars in the lifting process by MST software modeling. Besides, strengthening methods of bars are introduced.

Abstract: Presented in this paper is part of an experimental series conducted at different altitudes to investigate the influence of altitude on the flammable liquids flash point. The BS-1 closed bomb apparatus is used to measure the flash points of two flammable liquids (dimethylacetylamide (DMA) and RP-5 Jet A) in a hypobaric chamber under the altitude change from 4860 km to the sea level. The experimental results show that the flash points of DMA and Jet A decrease linearly with the increase in altitude in the low altitude region below the corresponding critical altitudes but non-linearly above. The critical altitudes for DMA and RP-5 Jet A are found to be 3 km and 3.83 km respectively. When the altitude reaches or surpasses the critical altitude, the flash point decreases rapidly. In particular, the flash point of the DMA exhibits a peculiar sudden transition above the critical altitude.

Abstract: Chemical looping hydrogen (CLH) has become a promising technology for hydrogen production with inherent separation of carbon dioxide. Aspen Plus was used to simulate a two-stage fuel reactor CLH process of coal as solid fuel. Simulation results show that the two-stage reactor can fully convert the fuel and generate the maximum Fe_0.947O component to react with the steam in steam reactor. The optimum OC/coal molar ratio in the two-stage fuel reactor was 2.8. The CO₂ fraction of the flue gas in the fuel reactor reached 99% when the vapor was condensed at the temperature of 950 °C. The fraction of dry-based H₂ in the steam reactor was nearly 100% when the steam reactor temperature was 700 °C and the steam/oxygen carrier molar ratio was 0.48.

Abstract: With the development of economy and the improvement of people's living level, improving living conditions and public buildings, architectural design requirements are also constantly improved. Modern architecture should consider not only beautiful and comfortable, but also take into account the design individuality, while taking into consideration the people-oriented design concept of environmental protection and energy saving. This also makes the environmental friendly and energy-saving building is the development direction of future architecture. This paper analyzes the modern architecture of the ecological and environmental protection, gives the method to realize the construction of energy-saving environmental protection design and the use of new materials, new equipment and new technology of the existing.

Abstract: Ecosystem accounts a lot to human survival and development. Ecological / environmental services has become an important part of the whole economic system functioning. Thus, from the perspective of environmental fairness and environmental controversies, pay for environmental services has become an important tool of acknowledging ecological capital and solving environmental problems. With the development of tourism, tourism-related pay for environmental services also entered the perspective of researchers and practitioners. Tourism-related pay for environmental services becomes the priority areas for the implementation of pay for environmental services because of its relatively clear property rights, clear beneficiaries, and strong capacity of payment. At the same time, Tourism-related pay for environmental services becomes the focus of enhancing the efficiency of pay for environmental services because tourism has become an important way to ecological construction and solve problems of livelihoods of local communities. This paper first proposed definition of tourism-related pay for environmental services, and then examines the standards of pay for environmental services that remains the key issue of pay for environmental services. The purpose of the paper is to provide intellectual support for the implementation of important environmental management tools.