Field Load Test Based SHM System Safety Standard Determination for Rigid Frame Bridge

The deteriorated continuous rigid frame bridge is strengthened by external prestressing. Static loading tests wereconducted before and after the bridge rehabilitation to verify the effectiveness of the rehabilitation process. Thestiffness of the repaired bridge is improved, and the maximum deflection of the load test is reduced from 37.9 to27.6 mm. A bridge health monitoring system is installed after the bridge is reinforced. To achieve an easy assessmentof the bridge’s safety status by directly using transferred data, a real-time safety warning system is createdbased on a five-level safety standard. The threshold for each safety level will be determined by theoretical calculationsand the outcomes of static loading tests. The highest risk threshold will be set at the ultimate limit statevalue. The remaining levels, namely middle risk, low risk, and very low risk, will be determined usingreduction coefficients of 0.95, 0.9, and 0.8, respectively.

Field load testing of copper extraction aeration pipes under simulated high heap pile

Recently a research team at Ohio University,USA,conducted a unique full-scale feld load test to simulate the aeration pipe installations at a copper extraction mine operated in Chile.The overliner material taken from the mine was used in recreating the in situ conditions.Electric heaters were utilized to raise the temperature inside each pipe to simulate the essential element of the copper extraction process.The maximum vertical deflection reached by the test pipes was close to 20%,when the simulated heap pile height was 80 m.The plastic pipes and the overliner material were also tested in the laboratory.Based on the results,the maximum heap pile fll depth was recommended for the aeration system.The results indicated that the vertical deflection was the primary performance index for the aeration pipes installed in heap piles at mines.Lastly,the pipe made of polypropylene resin was super.

Performance investigation of plasma magnetohydrodynamic power generator

A magnetohydrodynamic （MHD） power generator system involves several subjects such as magnetohydrodynamics, plasma physics, material science, and structure mechanics. Therefore, the performance of the MHD power generator is affected by many factors, among which the load coefficient k is of great importance. This paper reveals the effect of some system parameters on the performance by three-dimensional （3D） numerical simulation for a Faraday type MHD power generator using He/Xe as working plasma. The results show that average electrical conductivity increases first and then decreases with the addition of magnetic field intensity. Electrical conductivity reaches the maximum value of 11.05 S/m, while the applied magnetic field strength is B = 1.75 T. When B 〉 3 T, the ionization rate along the midline well keeps stable, which indicates that the ionization rate and three-body recombination rate （three kinds of particles combining to two kinds of particles） are approximately equal, and the relatively stable plasma structure of the mainstream is preserved. Efficiency of power generation of the Faraday type channel increases with an increment of the load factor. However, enthalpy extraction first increases to a certain value, and then decreases with the load factor. The enthalpy extraction rate reaches the maximum when the load coefficient k equals 0.625, which is the best performance of the power generator channel with the maximum electricity production.