Improved AHP Assessment Model and Its Practice in Geological Hazard Susceptibility Zoning

Based on the problem during the practice in geological hazard susceptibility zoning, by constructing the three mark (-1,0,1) matrix and introducing optimum transfer matrix, the faintness about weight choice and the consistency check method of judgment matrix for traditional AHP were improved,and the difficult weight quantization problem for each appraise factor of the hiberarchy model had been solved; accordingly, the Improved AHP model had been built. At the last, this method was applied to a concrete zoning practice about geological hazard susceptibility.The application result shows that the zoning practice in Yongchuan region about geological hazard susceptibility is practical and effective.     

A Land Use Model for Urban Rail Station Area Planning Based on TOD Strategy

Transit oriented development (TOD) presents a sustainable urban development strategy by creating an efficient integration of land use and public transit. A TOD planning model for the land use of urban rail station area was explored by means of a multiple objective mathematical programming model. Three objectives were considered: encouraging transit system volume, promoting livable communities, and balancing land use. The model can easily be solved by transforming it into a linear multi programming problem. The Xujiahui rail rapid transit station area in Shanghai is chosen as case study to illustrate the model application and planning results. The result indicates that the model would be efficient in practice.     

Mechanism and Influencing Factors of Concentrated Phosphate Removal by Calcite

The phosphate removal mechanisms of Calcite were investigated with the tests of X ray diffraction (XRD) analysis, transmission electron microscope (TEM) measurement, fourier transform infrared spectroscopy (FT IR) analysis , specific surface area by Brunauer Emmett Teller(BET) method and pole size distribution by Barrett Joyner Halenda(BJH) method. The main influencing factors on phosphate removal were investigated and the removal mechanism was approved. It was shown that phosphate removal efficiency was significantly influenced by reaction time, temperature, pH value and dosage of calcite. And with BET, BJH and TEM tests, no porous materials, less than 16.0 m2/g for the specific surface area and below 0.085 cm3/g for total pore volume, were found during the reaction process so as to prove that absorption was not the main way of phosphate removal. And based on XRD and FT IR tests, it was found that chemical precipitation was the main way of phosphate removal which contained two steps: the formation of CaHPO4·2H2O(DCPD) and its transformation to ACP, and the controlling step was DCPD’s transformation to ACP.     

Torsion behavior of Steel encased Concrete Composite Beams

In order to study torsion behavior of steel encased concrete composite beams, experiments were carried out with eight specimens. The destruction shape, working mechanism and the crack development and distribution were analyzed under pure torsion and combine torsion conditions. And also the relationships were investigated between torque and torsion ratio, load and strain, bending moment and deflection and load crack. On the basis of elasticity plastic theory, the formulas of cracking torsion were presented for pure torsion and combined torsion of combined beam. And with spatial truss model of variable angle, formulas for ultimate torsion strength of pure torsion and combined torsion were put forward. The predicted results were in good agreement with measured ones. The proposed formulas provided basis for evaluating safety and stability of the structural.     

Theory and approach to reactive power flow tracing

Based on an analysis of the characteristics of reactive power supplies and reactive loads, this paper presents a method for forming a lossless reactive network using an equivalent technique of modeling the branch admittance as a reactive power supply and the branch power loss as a virtual load. A downstream distribution matrix for a power system is constructed based on its reactive lossless network, and the analytical model and its algorithm for tracing reactive power flow (TRPF) is proposed. A method dealing with the abnormal downstream distribution matrix of active power flow also is discussed. The main advantage of the proposed method is that the matrix theory is used to analyze the TRPF model directly and no assumption on the flow distribution is needed. Case studies of the IEEE14 Bus and IEEE30 Bus systems demonstrate the accuracy and the validity of the proposed method.     

Simulation study of stochastic fluctuating wind field for wind turbine blades

The differences of the wind field model between wind turbines and common architectures are investigated. It is indicated that substantial frequency contents are transferred to rotor rotation frequency and its harmonics due to the periodic motions of blade. According to standard von Karman power spectral density (PSD) model and rotationally sampled PSD model, the PSD matrix for turbulence on blades of wind turbine is setup. The longitudinal turbulence’s time serials is simulated based on the superimposition of harmonic waves.     

Numerical simulation of the influences of catalytic wall on methane combustion characteristics in micro combustor

In order to study the effects of different catalytic walls on combustion characteristics, the premixed catalytic combustion characteristics of methane/air in micro combustor are studied. It lays the foundation for the combustion technology of hydrocarbon fuel in micro engine. Numerical simulation of flow and catalytic combustion in micro combustor was done by using laminar finite rate and second order upwind discretization methods. The results show that when wall temperature,CH4/O2 mole ratio and methane mass flow rate change, the influence of lower catalytic wall on the methane catalytic combustion efficiency is biggest, followed by side catalytic wall, the smallest is upper catalytic wall. The methane catalytic combustion efficiency unit area of lower catalytic wall is about three times of that of upper catalytic wall. The utilization of catalyst on lower catalytic wall is maximal . Therefore, when coating catalyst, the quantity of katalyst on lower catalytic wall should be appropriate more, moderate on the side catalytic wall, as little as possible on the upper catalytic wall. The influence disciplinarian and contribution rate of different catalytic wall on methane combustion have been gained. The optimized strategy of catalyst coating was put forward and reduced the cost of catalytic combustion.     

Simplifying and validating the model of wet flue gas desulphurization spray tower for 660MW units

The wet limestone gypsum flue gas desulphurization system for 660 MW units of a thermal power plant is taken as the object, based on the study of the mass transfer between the gas phase and the liquid phase、chemical reaction mechanism in desulphurization tower and reasonable simplified hypothesis, the turbulent mathematical model of the spray type tower is developed by the methods of concentration of parameters and module modeling. The model is validated by the test of stable state and the turbulent experiments, which can be used as the basis for developing the real training simulation model of the desulphurization system.     

The Effect of Slabs on the Failure Mode of Reinforced Concrete Frame Structures

A majority of reinforced concrete frame structure failure patterns resulting from the May 12, 2008 earthquake in Wenchuan County, P. R. China were analyzed. It was found that the main failure mode of frame works was “strong beam, weak column”, which conflicts with the design criteria of “strong column, weak beam”. The cause of this failure pattern was analyzed. A new concept is put forward that should be considered in design work. The over strength caused by slabs connected monolithically to the beams is analyzed. The joint types, transverse beam stiffness and lateral drift influence the reinforcing effect of the sla, Moreover, a reinforced concrete frame model was simulated using the program ABAQUS. The slab reinforcement stress distributions at different lateral drifts were analyzed and the effective flange width value proposed.