Applied Mechanics and Materials Vol. 730

Abstract: Thermal conductivity is one of the key factors influence the heat exchange performance of Ground-coupled heat pump systems (GCHP), which is effected significantly by soil moisture content around the ground heat exchanger system. The clay thermal conductivity under moisture content of 0, 5%, 10%, 15%, 20%, 25% and 30% were determined through thermal conductivity probe experiment. The results showed a variation with three phases of the thermal conductivity changes with clay moisture content, that firstly, the thermal conductivity increased slowly with a moisture content of 0~5%, secondly, which sharply increased with a high positive linear correlation when the moisture content was 5%~25%, then the growth tendency was slow even began to fall, as well as the correlation equation of the second phase was fitted. This study provides methodological and theoretical references for the further research on the influence factors of thermal conductivity under various situations.

Abstract: The flexural behavior of reinforced concrete beams strengthened by CFRP is analyzed by using the way which connected tests with finite element simulation.First,through the test to get the load data of one unstrengthened and one strengthened reinforced concrete beam.Then,the finite element model is carried out based on Ansys finite element analysis software.The reinforced beam carrying capacity is improved based on the test data and finite element calculation results.Steel bars stress change curve, CFRP stress curve and the load displacement curves are in good agreement with experimental results.

Abstract: Large energy consumption, serious pollution and poor quality of indoor thermal environment are generally seen during construction in villages and towns in China nowadays, leading to poor building insulation performance. Envolope of enclosure of a buidling is key to its insulation performance. Material selection of building enclosures and green design of construction technology are the key to promoting insulation performance of the building as villages and towns in cold region are subject to special geographical position, climate conditions and economic factors. With a focus on research of traditional non-wood fibrous material modification with existing technology and the engineering practice in non-wood fibre roof in villages and towns of cold region, this paper came up with the prospects of its applicatin in the following design strategies including “ecological and conservation-oriented roofing with modified local materials, new hybrid roofing with simplified construction technology and paper tensioning roofing with innovative synthetic materials”.

Abstract: It is important to analyze the temperature, airflow field, PMV-PPD index distribution within the passenger compartment to ameliorate the amenity and decrease consumption. A numerical model to assess the thermal comfort taking into account the different air velocity. This paper uses commercial software FLUENT to simulate 3-D temperature, PMV-PPD index distributions and flow field in a compartment passenger. The predicted results basically meet the requirement of thermal comfort except the local temperature around the lower region and the local air velocities around passengers’ head region. When the air-outlet temperature is 20 °C, air-outlet velocity 4 m/s is agreed to the thermal comfort. PMV index are about -0.4-0.6, and PPD index is less than 10%, which is agreed with passenger’s thermal comfort. The predicted values illustrate the uniformity of indoor environment in the occupied zone.

Abstract: The height of the water flowing fractured zone and the extent of water inrush caused by coal mining are the main influence factors on aquifer systems. Taking a coal mine of Shanxi province as research object, the impact of coal mining on regional surface water and groundwater was evaluated. The heights of the water flowing fractured zone of coal seams in No.3, No.8-2, No.15-1 and No.15-3 were 68.62~98.62m, 31.21~58.25m, 30.59~33.41m and 31.45~42.33m respectively. The results showed that the surface would not be penetrated and the surface water environment could not be impacted seriously. While the lower shihezi formation aquifer which was the mined-out area of coal seams in No.3 and No.8-2 would be penetrated. Coal seam in No.15-3 belongs to relatively safe area, which water inrush coefficient ranged from 0MPa/m to 0.0148MPa/m.

Abstract: Due to the complexity of cataclastic rock structure, joint development, cataclastic rock bolting is a difficult problem to solve. According to roadway engineering properties and deformation characteristics of liu qiao one ore two level six mining area-380 transport cross section, choose one supporting form, adopt the method of numerical simulation to analysis its supporting effect, to ensure the stability of surrounding rock and the safe running of the roadway.

Abstract: The numerical tests of the optimized drainage parameters in a high drainage roadway were conducted with different inlet air velocities, drainage ratios and integrity lengths. The results show that the upper corner's gas concentration decreases gradually with the inlet air velocity and drainage ratio increasing, while there have not obvious change with the Different Integrity Lengthss. Considering from the gas control and gas drainage, the reasonable inlet air velocity is 1-1.25m/s and the right drainage ratio is about 0.3.

Abstract: The numerical tests of the optimized high drainage roadway location in a fully mechanized coal face were conducted with different vertical distances and horizontal distances. The results show that higher vertical distance of high drainage roadway is beneficial for upper corner safety and gas control, and the optimal vertical distance of the high drainage roadway in the studied coal face is 30m-45m, and the best horizontal distance is about 30m.

Abstract: Through the establishment of a lift transport platform finite element model, using Ansys / workbench to calculate its corresponding analysis to improve performance and meet the requirements, as well as improve design efficiency and reduce the cost.

Abstract: The intensities of the dipole, quadrupole and octupole modes for gold nanoshells have been investigated with various dielectric constants for the embedding medium and with various sizes of the nanoshells by means of Mie theory. With the increase in the dielectric constant of embedding medium, it is found that the intensities of all modes become stronger first, and then the higher mode starts to become weak. We also observe with decreasing the core size of a nanoshell with a fixed outer radius, a larger dielectric constant for the embedding medium is needed corresponding to the change of higher mode intensities from stronger to weaker. We have ascribed the changes of the dipole, quadrupole and octupole modes to the competition among the variations of induced surface charges, conduction electrons and oscillation electrons.