A method utilizing variable depth increments during incremental forming was proposed and then optimized based on numerical simulation and intelligent algorithm. Initially, a finite element method (FEM) model was set up and then experimentally verified. And the relation between depth increment and the minimum thickness t_min as well as its location was analyzed through the FEM model. Afterwards, the variation of depth increments was defined. The designed part was divided into three areas according to the main deformation mechanism, with D_i (i=1, 2) representing the two dividing locations. And three different values of depth increment, Δz_i (i=1, 2, 3) were utilized for the three areas, respectively. Additionally, an orthogonal test was established to research the relation between the five process parameters (D and Δz) and t_min as well as its location. The result shows that Δz2 has the most significant influence on the thickness distribution for the corresponding area is the largest one. Finally, a single evaluating indicator, taking into account of both t_min and its location, was formatted with a linear weighted model. And the process parameters were optimized through a genetic algorithm integrated with an artificial neural network based on the evaluating index. The result shows that the proposed algorithm is satisfactory for the optimization of variable depth increment.

A new style Ni-containing alumina ceramic foam based continuous three-dimensional interconnected skeleton was prepared by impregnating a polymeric sponge with aqueous ceramic slurry. Subsequently, alumina ceramic foam/steel metal matrix composites (MMCs) were prepared successfully by sand mold casting technique. The microstructure and mechanical properties of MMCs were investigated by SEM, EDS and compressive test. The results show that the depth of infiltration is about 40 μm to the bonding interface of ceramic/steel and the fracture strength σ_max and plastic strain limit ɛ_p of composite are 520 MPa and 11.2%, respectively. The fretting wear mechanism of MMCs is mainly performed at the oxidative wear mode with lower load/friction frequency and the predominant oxidation wear together with slight adhesive wear and abrasive wear multiple mode with higher load/friction frequency. Moreover, the infiltration bonding and continuous three-dimensional interconnected ceramic skeleton play a vital role in the stability of the bonding interface and excellent mechanical properties.

Contrastive research was carried out to study the thermal properties of open-celled aluminum foams prepared by counter-gravity infiltration casting system and the traditional process respectively. The experimental results show that the thermal conductivity coefficients of aluminum foams prepared by two different infiltration methods have similar increasing trend with the increase of particle size; along with the reducing porosity, the thermal conductivity coefficients will be enhanced oppositely. However, with the same particle size, the open-celled aluminum foam prepared by the former method has a higher thermal conductivity coefficient obviously. It is largely because that the sample prepared by counter-gravity infiltration casting has a lower void content and better dense crystallization of metal-matrix after the constant pressure process.

The piezoelectric effect is used in sensing applications such as in force and displacement sensors. However, the brittleness and low performance of piezoceramic lead zirconate titanate (PZT) often impede its applicability in civil structures which are subjected to large loads. The concept of a piezocomposite electricity generating element (PCGE) has been proposed for improving the electricity generation performance and overcoming the brittleness of piezoceramic wafers. The post-curing residual stress in the PZT layer constitutes a main reason for the PCGE’s enhanced performance, and the outer epoxy-based composites protect the brittle PZT layer. A d₃₃-mode PCGE designed for bridge monitoring application was inserted in a bridge bearing to provide a permanent and simple weigh-in-motion system. The designed PCGEs were tested through a series of tests including fatigue and dynamic tests to verify their applicability for monitoring purposes in a bridge structure. A simple beam example was presented to show the applicability of the proposed bridge bearing equipped with the PCGE for adequately measuring the traffic loads.

Multiple surface cracks and interfacial delamination are the major failure mechanisms in film/substrate systems. The effect of interlayer upon the failure mechanisms of interfacial delamination concomitant to surface crack was explored. Finite element model was developed to obtain the stress and energy release rate (ERR), which governs the propagation of interface cracks. The dependences of delamination upon the geometry and constitutive properties of interlayer were examined. The results indicate that the effect of elastic modulus of interlayer on the steady state ERR is insignificant. In cases of different geometrical parameters, however, the steady ERR decreases with the increase of the interlayer thickness. These findings lead to the conclusion that the interlayer constraint has significant effect on the ERR and thus coating life, which can be adopted to modify the ceramic top coat.

Using the first-principles calculations based on density functional theory (DFT), the structure stability, electronic and some optical properties of C and N doped cubic ZrO₂ (c-ZrO₂) in 24-atom systems were investigated. It is found from the formation energies calculations that N ions are easier to be doped into c-ZrO₂ than C ions. The electronic structure results show that Zr₈O₁₅C and Zr₈O₁₅N systems are semiconductors with the band gap of 2.3 eV and 2.8 eV, respectively, which are lower than that of the pure ZrO₂ (3.349 eV). And optical properties results depict that anion doping, especially C adding, can enhance the static dielectric function, visible and ultraviolet light absorption and reflecting ability of c-ZrO₂ crystal.

Before densification by chemical vapor infiltration, carbon or SiC nanofibers were grown on the surface of carbon fibers by catalytic chemical vapor deposition using electroplated Ni as catalyst. The modification and mechanism of nanofibers on the pyrocarbon deposition during chemical vapor infiltration were investigated. The results show that the nanofibers improve the surface activity of the carbon fibers and become active nucleation centers during chemical vapor infiltration. They can induce the ordered deposition of pyrocarbon and adjust the interface bonding between pyrocarbon and carbon fibers during the infiltration.

A reduced graphene oxide/Ni(OH)₂ composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used. XRD and SEM results reveal that the nickel hydroxide, which crystallizes into hexagonal β-Ni(OH)₂ nanoflakes with a diameter less than 200 nm and a thickness of about 10 nm, is well combined with the reduced graphene oxide sheets. Electrochemical performance of the synthesized composite as an electrode material was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements. Its specific capacitance is determined to be 1672 F/g at a scan rate of 2 mV/s, and 696 F/g at a high scan rate of 50 mV/s. After 2000 cycles at a current density of 10 A/g, the composite exhibits a specific capacitance of 969 F/g, retaining about 86% of its initial capacitance. The composite delivers a high energy density of 83.6 W·h/kg at a power density of 1.0 kW/kg. The excellent supercapacitive performance along with the easy synthesis method allows the synthesized composite to be promising for supercapacitor applications.

High dispersed carbon black was applied for LiFePO₄ cathodes as conductive agent. Nano-conductive carbon agent was pre-dispersed with poly acrylic acid (PAA) as dispersant in organic N-methyl-pyrrolidone (NMP) solvent system. The dispersion property of nano-conductive carbon agent was evaluated using particle size distribution measurements, scanning electron microscopy (SEM) and transmission electron microscope (TEM). LiFePO₄ cathode with as-received nano-conductive carbon agent (SP) and LiFePO₄ cathode with pre-dispersed nano-conductive carbon agent (SP-PAA) were examined by scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impendence spectroscopy (EIS) and charge/discharge cycling performance. Results show that the dispersion property of carbon black is improved by using PAA as the dispersant. The LiFePO₄ cathodes with SP-PAA exhibit improved rate behaviors (4C, 135.1 mAh/g) and cycle performance (95%, 200 cycles) compared to LiFePO₄ cathodes with SP (4C, 103.9 mAh/g and 83%, 200 cycles). Because pre-dispersed carbon black (SP-PAA) is dispersed homogeneously in the dried composite electrode to form a more uniform conductive network between the active material particles, electrochemical performances of the LiFePO₄ cathodes are improved.

Large complex 7A85 aluminum wing-body joint was forged employing isothermal forging process and its mechanical properties were studied. The tensile strength after forging is up to 587.5 MPa in longitudinal direction, 15% higher than that using free forging. Moreover, the tensile strength of the forging is almost the same in three directions. Isothermal forging also performs well on overall fracture toughness, with a maximum value of 39.8 MPa·m^1/2, and that of short transverse direction all reaches 36 MPa·m^1/2 and above, with a maximum relative error of only 3.6%. The results indicate that the isothermal forging leads to better performance as well as higher uniformity in mechanical properties.

The experimental die apparatus of the solid granules medium forming on sheet metal was designed and manufactured. Typical parts, such as conical, parabolic, cylindrical and square-box-shaped components, were successfully trial-produced as well. According to the analysis of the changing trends of the cross-section shape and the wall thickness during the process, it can be found that the shape of the free deformation zone of the sheet metal, which is the most critical thinning area, can be described as an approximately spherical cap. According to this forming feature, back pressure deep drawing technology with solid granules medium on sheet metal was proposed to restrain drastic thinning at the bottom of the part through the joint friction effect of solid granules medium, the back pressure tringle and the sheet metal. Therefore, the deep drawing limit of the sheet metal is significantly improved. In order to fabricate thin-walled rotary parts with great drawing ratio and complex cross-sections, a finite element model based on the material property test of the solid granules medium was established to optimize the scheme of the back pressure deep drawing. The effects on the forming performance of sheet metal from back pressure load and the approach of blank holding control were analyzed through this model.

Traditional treatments of zinc dross have many disadvantages, such as complicated recovering process and serious environmental pollution. In this work, a new process of chlorine removal from zinc dross by microwave was proposed for solving problem of recycling the zinc dross. With better ability of absorbing the microwave than zinc oxide, the main material in zinc dross, chlorides, can be heated and evaporated rapidly during microwave roasting. Various parameters including roasting temperature, duration time and stirring speed were optimized. The microstructure of roasted materials was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The content of the chloride was analyzed by the method of chlorine ion selective electrode. The experiments indicate that the best duration time is 60 min with a stirring speed of 15 r/min during the microwave roasting process. The dechlorination rate reaches peak value of 88% at 700 °C. The chlorine is removed as HCl gas when water vapor is used as activating agent, which means that it can be recovered into hydrochloride acid.

Bacterial leaching of single sulfide minerals and polymetallic sulfide ores was operated in shake flasks and small-scaled columns. The results show that bioleaching of jamesonite is not accessible, the iron extraction rate of pyrrhotite bioleaching reaches 98.2% after 26 d, and the zinc extraction rate of marmatite bioleaching reaches 92.3%, while the corresponding iron extraction reaches only 13.6% after 29 d. Pulp density has a significant effect on metal extraction of pyrrhotite and marmatite bioleaching. The corresponding metal extraction rate decreases with the increase of pulp density. For the polymetallic sulfide ores, zinc extraction of 97.1% is achieved after bioleaching in shake flasks for 10 d, while only 7.8% is obtained after bioleaching in small-scaled column. Analytical results of scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) reveal that large amount of calcium sulfate is formed on the mineral surface.

The bioleaching of pyrrhotite was investigated using Sulfobacillus thermosulfidooxidans. The effects of pH, pulp concentration, inoculation amount, external addition of ferrous and ferric ions were examined. The pH is found to exert a profound effect on the leaching process for controlling the bacterial activity and precipitation of ferric ions mainly as jarosite. The results show that low pulp content increases the leaching rate of iron. The inoculation amount from 1×10⁷ cell/mL to 1×10⁸ cell/mL has positive effects on the leaching rate. The results also imply that addition of ferrous sulfate (1 g/L) is required for the bacteria to efficiently drive the extraction of iron, however, the leaching efficiency has no obvious enhancement when 2 g/L ferrous sulfate was added. Comparatively, addition of ferric sulfate (2 g/L) significantly inhibits the bioleaching process. At the end of bioleaching, jarosite and sulfur are observed on the surface of pyrrhotite residues by using XRD and SEM. With the passivation film formed by jarosite and sulfur, the continuous iron extraction is effectively blocked.

The human plasma protein binding of water soluble flavonoids in the peels of five spices of citrus fruits was studied by ultrafiltration combined with HPLC. The flavonoids were extracted separately by hot and cold water, and higher total flavonoid contents were detected in the former extracts than the latter ones. All the extracts show significant scavenging abilities to both ABTS and DPPH free radicals, which indicates the health benefits of the water extracts of citrus fruits peels. For DPPH radical, the IC₅₀ values of hot extract follow as Navel orange (NO)≈Mandarin orange (MO)< Lemon (LE)< Lo tangerine (LO)< Pomelo (PO), while the rank is NO< PO<LE≈MO<LO for ABTS radical. The HPLC results reveal that the kinds and contents of the flavonoids detected in the extracts are different among the species. MO extract has the most neohesperidin dihydrochalcone of 118.76 μmol/L and quercetrin of 211.81 μmol/L of which are much more than the rest extracts. Pomelo extract has the most plentiful flavonoids of naringin with a concentration of 303.28 μmol/L. The high contents of myricetrin and dihydromyricetin which both are potent free radical scavengers may explain the highest free radical scavenging activity of the NO extract. The plasma binding rates decrease with the increasing concentrations of flavonoids, and the flavonoids having plenty hydroxyl groups on both A ring and B ring of the molecular skeleton have relative higher plasma binding rates. In addition, the plasma binding rates of flavonoids with saturated C3–C4 bond decrease significantly with the increasing concentrations.

Inverse speed is a reversible maneuver. It is a characteristic of underwater vehicle at low speed. Maneuverability in the vertical plane at a speed lower than inverse speed is different from one at higher speed. In the process of underwater working for observation, AUV’s cruise speed is always low. Therefore, the research on inverse speed is important to AUV’s maneuverability. The mechanism of inverse speed was analyzed, and then the steady pitching equation was derived. The parameter expression of track angle in vertical plane was deduced. Furthermore, the formula to calculate the inverse speed was obtained. The typical inverse speed phenomenon of the flat body and the revolving body was analyzed. Then the conclusion depicts that, for a particular AUV with flat body, its inverse speed is lower than that of revolving body. After all the calculation and the analysis, a series of special experiments of inverse speed were carried out in the simulation program, in the tank and in the sea trial.

Kinematics and dynamics analyses were performed for a spatial 3-revolute joint-revolute joint-clylindric pair (3-RRC) parallel manipulator. This 3-RRC parallel manipulator is composed of a moving platform, a base platform, and three revolute joint-revolute joint-column pair chains which connect the moving platform and the base platform. Firstly, kinematics analysis for 3-RRC parallel manipulator was conducted. Next, on the basis of Lagrange formula, a simply-structured dynamic model of 3-RRC parallel manipulator was derived. Finally, through a calculation example, the variation of motorial parameters of this 3-RRC parallel manipulator, equivalent moment of inertia, driving force/torque and energy consumption was discussed. The research findings have important significance for research and engineering projects such as analyzing dynamic features, mechanism optimization design and control of 3-RRC parallel manipulator.

Stress analysis of cylindrical grid-stiffened composite shells was conducted under transverse loading, pure bending, torsion and axial compression under clamped-free boundary condition. Electrical strain gauges were employed to measure the strains in transverse loading case to validate the finite element analysis which was conducted using ANSYS software. Good agreement was obtained between the two methods. It was observed that stiffening the composite shell with helical ribs decreased the average equivalent Von Mises stress on the shell. The reduction of the stress seemed to be higher in the intersection of two ribs. It was also seen that the stress reduction ratio was higher when the structure was under bending compared to torsion and axial compression. The reduction ratio was approximately 75% in pure bending in the intersection point of the ribs, while it was approximately 25% in torsion. Therefore, it is concluded that the presence of the ribs is more effective under bending. Failure analysis was done using Tsai-Wu criterion. The ribs were observed to result in maximum and minimum increase in the failure load of the structure under transverse bending and torsional loading, respectively.

As to the fact that it is difficult to obtain analytical form of optimal sampling density and tracking performance of standard particle probability hypothesis density (P-PHD) filter would decline when clustering algorithm is used to extract target states, a free clustering optimal P-PHD (FCO-P-PHD) filter is proposed. This method can lead to obtainment of analytical form of optimal sampling density of P-PHD filter and realization of optimal P-PHD filter without use of clustering algorithms in extraction target states. Besides, as sate extraction method in FCO-P-PHD filter is coupled with the process of obtaining analytical form for optimal sampling density, through decoupling process, a new single-sensor free clustering state extraction method is proposed. By combining this method with standard P-PHD filter, FC-P-PHD filter can be obtained, which significantly improves the tracking performance of P-PHD filter. In the end, the effectiveness of proposed algorithms and their advantages over other algorithms are validated through several simulation experiments.

Fuzzy logic controller adopting unevenly-distributed membership function was presented with the purpose of enhancing performance of the temperature control precision and robustness for the chamber cooling system. Histogram equalization and noise detection were performed to modify the evenly-distributed membership functions of error and error change rate into unevenly-distributed membership functions. Then, the experimental results with evenly and unevenly distributed membership functions were compared under the same outside environment conditions. The experimental results show that the steady-state error is reduced around 40% and the noise disturbance is rejected successfully even though noise range is 60% of the control precision range. The control precision is improved by reducing the steady-state error and the robustness is enhanced by rejecting noise disturbance through the fuzzy logic controller with unevenly-distributed membership function. Moreover, the system energy efficiency and lifetime of electronic expansion valve (EEV) installed in chamber cooling system are improved by adopting the unevenly-distributed membership function.

Adaptive Type-2 fuzzy control possesses control performance better than the traditional adaptive fuzzy control. However, heavy computation burden obviously blocks the utilization of adaptive Type-2 fuzzy control in industrial application. By adopting novel piecewise fuzzy sets and center-average type-reduction, a simplified adaptive interval Type-2 fuzzy controller involving less computation is developed for practical industrial application. In the proposed controller, the inputs are divided into several subintervals and then two piecewise fuzzy sets are used for each subinterval. With the manner of piecewise fuzzy sets and a novel fuzzy rules inference engine, only part of fuzzy rules are simultaneously activated in one control loop, which exponentially decreases the computation and makes the controller appropriate in industrial application. The simulation and experimental study, involving the popular magnetic levitation platform, shows the predicted system with theoretical stability and good tracking performance. The analysis indicates that there is far less computation of the proposed controller than the traditional adaptive interval Type-2 fuzzy controller, especially when the number of fuzzy rules and fuzzy sets is large, and the controller still maintains good control performance as the traditional one.

A novel configuration performance prediction approach with combination of principal component analysis (PCA) and support vector machine (SVM) was proposed. This method can estimate the performance parameter values of a newly configured product through soft computing technique instead of practical test experiments, which helps to evaluate whether or not the product variant can satisfy the customers’ individual requirements. The PCA technique was used to reduce and orthogonalize the module parameters that affect the product performance. Then, these extracted features were used as new input variables in SVM model to mine knowledge from the limited existing product data. The performance values of a newly configured product can be predicted by means of the trained SVM models. This PCA-SVM method can ensure that the performance prediction is executed rapidly and accurately, even under the small sample conditions. The applicability of the proposed method was verified on a family of plate electrostatic precipitators.

Two new methods were presented for power flow tracing (PFT). These two methods were compared and the results were discussed in detail. Both methods use the active and reactive power balance equations at each bus in order to solve the tracing problem. The first method considers the proportional sharing assumption while the second one uses the circuit laws to find the relationship between power inflows and outflows through each line, generator and load connected to each bus of the network. Both methods are able to handle loop flow and loss issues in tracing problem. A formulation is also proposed to find the share of each unit in provision of each load. These methods are applied to find the producer and consumer’s shares on the cost of transmission for each line in different case studies. As the results of these studies show, both methods can effectively solve the PFT problem.

The application of various artificial intelligent (AI) techniques, namely artificial neural network (ANN), adaptive neuro fuzzy interface system (ANFIS), genetic algorithm optimized least square support vector machine (GA-LSSVM) and multivariable regression (MVR) models was presented to identify the real power transfer between generators and loads. These AI techniques adopt supervised learning, which first uses modified nodal equation (MNE) method to determine real power contribution from each generator to loads. Then the results of MNE method and load flow information are utilized to estimate the power transfer using AI techniques. The 25-bus equivalent system of south Malaysia is utilized as a test system to illustrate the effectiveness of various AI methods compared to that of the MNE method.

A novel chaotic search method is proposed, and a hybrid algorithm combining particle swarm optimization (PSO) with this new method, called CLSPSO, is put forward to solve 14 integer and mixed integer programming problems. The performances of CLSPSO are compared with those of other five hybrid algorithms combining PSO with chaotic search methods. Experimental results indicate that in terms of robustness and final convergence speed, CLSPSO is better than other five algorithms in solving many of these problems. Furthermore, CLSPSO exhibits good performance in solving two high-dimensional problems, and it finds better solutions than the known ones. A performance index (PI) is introduced to fairly compare the above six algorithms, and the obtained values of (PI) in three cases demonstrate that CLSPSO is superior to all the other five algorithms under the same conditions.

The Khatri-Rao (KR) subspace method is a high resolution method for direction-of-arrival (DOA) estimation. Combined with 2q level nested array, the KR subspace method can detect O(N^2q) sources with N sensors. However, the method cannot be applicable to Gaussian sources when q is equal to or greater than 2 since it needs to use 2q-th order cumulants. In this work, a novel approach is presented to conduct DOA estimation by constructing a fourth order difference co-array. Unlike the existing DOA estimation method based on the KR product and 2q level nested array, the proposed method only uses second order statistics, so it can be employed to Gaussian sources as well as non-Gaussian sources. By exploiting a four-level nested array with N elements, our method can also identify O(N⁴) sources. In order to estimate the wideband signals, the proposed method is extended to the wideband scenarios. Simulation results demonstrate that, compared to the state of the art KR subspace based methods, the new method achieves higher resolution.

The original nonlinear chirp scaling (NCS) algorithm was extended for high precision processing of the highly squinted curvilinear trajectory synthetic aperture radar (CTSAR). Based on the analysis of slant range model and the frequency spectrum characteristics of the echo signal, a novel nonlinear chirp scaling function and more complex phase compensation factors with both velocity and acceleration parameters were proposed in the new algorithm for accommodation to curvilinear trajectory. The processing flow and computational complexity of modified NCS algorithm were fundamentally the same as the original NCS algorithm. However, the higher order phase compensation, range cell migration correction (RCMC) and range-variant secondary range compression (SRC) caused by the non-linear aperture and the severe range-azimuth coupling were accomplished accurately and efficiently without interpolation. Simulation results show that data acquired with a curvilinear aperture and a squint angle up to about 50° for X-band can be processed with no evident degradation of impulse response function.

Numerical computation models of air cooling heat transfer and flow behaviors in triangular wavy fin channels (TWFC) were established with structural parameters of fins considered. The air side properties of heat transfer coefficient and pressure drop are displayed with variable structural parameters of fins and inlet velocities of cooling air. Within the range of simulation, TWFC has the best comprehensive performance when inlet velocity v_in=4−10 m/s. Compared with those of straight fins, the simulation results reveal that the triangular wavy fin channels are of higher heat transfer performances especially with the fin structural parameters of fin-height F_h=9.0 mm, fin-pitch F_p=2.5−3.0 mm, fin-wavelength λ=14.0–17.5 mm and fin-wave-amplitude A=1.0–1.2 mm. The correlations of both heat transfer factor and friction factor are presented, and the deviations from the experimental measurements are within 20%.

A straightforward technique has been developed to quickly determine the wall contour of super/hypersonic nozzles working at multiply Mach number which share a common throat section. Mach number distribution along the centerline of the nozzle is specified in advance and divided into two sections, both of which are described by the b-spline function. The first section is shared by different exit Mach number nozzles. The nozzle contour is determined by the method of characteristics plus boundary layer correction. An example of this design method is employed to illustrate the technique with a computational fluid dynamics calculation. The simulation results indicate that desired Mach numbers are obtained at the nozzle exit, and the good flow quality is attained for different nozzles within δMa/Ma<±0.56% in the flow core region. This technique improves the design precision of the converging-diverging nozzle, cancels waves completely, and achieves nozzles with multiple Mach number exiting which share a common throat section.

The numerical simulation model for predicting fast filling process of 70 MPa type III (with metal liner) hydrogen vehicle cylinder was presented, which has considered turbulence, real gas effect and solid heat transfer issues. Through the numerical analysis method, the temperature distributions of the gas within the solid walls were revealed; adiabatic filling was studied to evaluate the heat dissipation during the filling; the influences of various filling conditions on temperature rise were analyzed in detail. Finally, cold filling was proposed to evaluate the effect on temperature rise and SoC (state of charge) within the cylinder. The hydrogen pre-cooling was proved to be an effective solution to reduce maximum temperature and acquire higher SoC during the filling process.

An optimal method for prediction and adjustment on byproduct gasholder level and self-provided power plant gas supply was proposed. This work raises the HP-ENN-LSSVM model based on the Hodrick-Prescott filter, Elman neural network and least squares support vector machines. Then, according to the prediction, the optimal adjustment process came up by a novel reasoning method to sustain the gasholder within safety zone and the self-provided power plant boilers in economic operation, and prevent unfavorable byproduct gas emission and equipment trip as well. The experiments using the practical production data show that the proposed method achieves high accurate predictions and the optimal byproduct gas distribution, which provides a remarkable guidance for reasonable scheduling of byproduct gas.

A novel method was developed to establish a realistic three dimensional (3D) network model representing pore space in low permeability sandstone. Digital core of rock sample was established by the combination of micro-CT scanning and image processing, then 3D pore-throat network model was extracted from the digital core through analyzing pore space topology, calculating pore-throat parameters and simplifying the shapes of pores and throats. The good agreements between predicted and measured porosity and absolute permeability verified the validity of this new network model. Gas-water flow mechanism was studied by using pore-scale simulations, and the influence of pore structure parameters, including coordination number, aspect ratio and shape factor, on gas-water flow, was investigated. The present simulation results show that with the increment of coordination number, gas flow ability in network improves and the effect of invading water on blocking gas flow weakens. The smaller the aspect ratio is, the stronger the anisotropy of the network is, resulting in the increase of seepage resistance. It is found that the shape factor mainly affects the end points in relative permeability curves, and for a highly irregular pore or throat with a small shape factor, the irreducible water saturation (S_wi) and residual gas saturation (S_gr) are relatively high.

Four types of common seaweeds (Laminaria japonica, Undaria pinnatifida, Porphyra haitanensis, and Gracilaria lemaneiformis) were examined to remove Cr(VI) ions from aqueous solution. The experimental parameters that affected the biosorption process including pH, biomass dosage, contact time and temperature were investigated via batch experiments. The surface characteristics of seaweeds before and after Cr(VI) adsorption were studied with scanning electron microscopy and Fourier transform infrared spectroscopy. The results show that an initial solution with the pH of 1.0 is most favorable for Cr(VI) adsorption. Rapid adsorption is observed in the initial stage and adsorption equilibrium state is reached within 1 h. The adsorption efficiency by Porphyra haitanensis is the maximum among four types of seaweed powders, followed by Laminaria japonica and Undaria pinnatifida with biosorption efficiency up to 90%. The removal rate of Gracilaria lemaneiformis is less than 60%. The kinetic data obtained using the seaweeds are found to follow pseudo-second order kinetic model. Experimental sorption data adequately correlate with the Langmuir model. FTIR indicates that amino and carboxyl groups play an important role in the process of Cr(VI) adsorption and a large percentage of Cr(VI) ions are reduced by reductive groups on the surface of seaweeds.

The Microcystis aeruginosa (MA) was immobilized on sodium alginate and used as biosorbent for removal of Cd(II) ions from aqueous solution. The biosorption process is pH dependent, and the optimum biosorption was observed at pH 6.0 with the biosorption capacity of 98.38 mg/g. Among Langmuir, Freundlich and Temkin isotherm models, the Freundlich and the Temkin isotherm fit well with the experimental data. Cd(II) ions biosorption follows the pseudo-second-order kinetic model. The rate controlling mechanism study reveals that film diffusion is the rate-limiting step and intraparticle diffusion is also involved in biosorption. Thermodynamic parameters, such as Gibbs free energy (ΔG^o), the enthalpy (ΔH^po) and entropy (ΔS^o) were calculated, and revealed that the biosorption process is spontaneous, exothermic and random. Furthermore, the immobilized MA can be regenerated using 0.1 mol/L HCl solutions.

Laboratory experiments were conducted to investigate the transformation and performance of a granular sequence batch reactor (SBR) under the conventional organic loading rate (OLR) condition. Aerobic granules were successfully cultivated in a SBR by means of alternative feeding load combined with reducing settling time after 60 d operational period. Subsequently, the black fungal granules were presented in reactor because of the filamentous overgrowth on the surface of aerobic granules. A small amount of fungal granules had no effect on the performance of granular SBR. Aerobic granules completely vanished and fungal granules eventually became the dominant species in subsequent 90 d operation after granulation. The three-dimensional excitation emission matrix (EEM) spectra result shows that the extracellular polymeric substances (EPS) component in both granules has no much difference, whereas the content of EPS in fungal granules is higher than that in bacterial granules. Due to their low bioactivity, the chemical oxidation demand (COD) and NH₄-N removal efficiencies gradually decrease from 90.4%–96.5% and 99.5% to 71.8% and 32.9% respectively while the fungal granules become dominant in the SBR.

Cross-linked chitosan(CS), cross-linked chitosan/graphene(CS/RGO₁₀) and cross-linked chitosan/graphene oxide(CS/GO₁₀) were prepared as adsorbents for Cu(II). The effects of pH, contact time, adsorbent dosage and initial concentration of Cu(II) on the adsorbing abilities of CS,CS/RGO₁₀ and CS/GO₁₀ to Cu(II) were investigated. The results demonstrate that the adsorption capacities of CS/GO₁₀ and CS/RGO₁₀ are greater than that of CS, especially at pH 5.0 and the adsorption capacities are 202.5, 150 and 137.5 mg/g, respectively. Their behaviors obey the Freundlich isotherm model very well. Additionally, CS/GO₁₀ has the shortest time to achieve adsorption equilibrium among them and can be used as a perspective adsorbent for Cu(II).

The spherical macroporous cellulose (SMC) was fabricated using medical absorbent cotton as raw material and nano CaCO₃ as porogenic agents. And then, the phenylglycine was grafted onto the SMC to obtain the novel spherical macroporous cellulose derivative adsorbent (PSMC). FT-IR and scanning electron microscope (SEM) were employed to characterize the adsorbents and Fe³⁺ ions served as model solute to evaluate the adsorption property of the adsorbents. The experimental results show that the amount of porogenic agents and the value of pH have obvious influence on adsorption capacity of the adsorbents. The data of adsorption kinetic and isotherm display that the adsorbents possess excellent equilibrium adsorption capacity (348.94 mg/g) and have a bright prospect and considerable potential in the treatment of Fe³⁺ ions in wastewater.

Zn₂GeO₄ nanorods were prepared by a surfactant-assisted solution phase route. The as-prepared products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), inductively coupled plasma atomic emission spectrometer (ICP-AES), UV-vis diffuse reflection spectroscopy and photoluminescence (PL) spectroscopy. The possible formation mechanism of Zn₂GeO₄ nanorods was discussed. It was supposed that the CTA⁺ cations preferentially adsorb on the planes of Zn₂GeO₄ nanorods, leading to preferential growth along the c-axis to form the Zn₂GeO₄ rods with larger aspect ratio and higher surface area, which showed the improved photocatalytic activity for photoreduction of CO₂. The photoluminescence (PL) property of Zn₂GeO₄ nanorods was investigated through the emission spectra.

Hydrogen sulfide in rural biogas was removed with liquid-phase catalytic oxidation. By using rare earth as catalyst, and sulfosalicylic acid as stabilizer, H₂S purification efficiency could increase as high as 96%, and sulfur capacity of the composite solution was about 3 g/L. The results show that purification efficiency was affected by catalyst addition, pH, experimental temperature, and sulfur capacity. The parameters effects on catalytic oxidation were studied, and the optimized conditions were that Fe³⁺ concentration 0.08 mg/L, reaction temperature 70°C, pH 9.0, with a absorption solution volume of 50 mL, a gas flow rate 200 mL/min, and H₂S mass concentration of 1.58–2.02 mg/m³.

Constrained long-term production scheduling problem (CLTPSP) of open pit mines has been extensively studied in the past few decades due to its wide application in mining projects and the computational challenges it poses become an NP-hard problem. This problem has major practical significance because the effectiveness of the schedules obtained has strong economical impact for any mining project. Despite of the rapid theoretical and technical advances in this field, heuristics is still the only viable approach for large scale industrial applications. This work presents an approach combining genetic algorithms (GAs) and Lagrangian relaxation (LR) to optimally determine the CLTPSP of open pit mines. GAs are stochastic, parallel search algorithms based on the natural selection and the process of evolution. LR method is known for handling large-scale separable problems; however, the convergence to the optimal solution can be slow. The proposed Lagrangian relaxation and genetic algorithms (LR-GAs) combines genetic algorithms into Lagrangian relaxation method to update the Lagrangian multipliers. This approach leads to improve the performance of Lagrangian relaxation method in solving CLTPSP. Numerical results demonstrate that the LR method using GAs to improve its performance speeding up the convergence. Subsequently, highly near-optimal solution to the CLTPSP can be achieved by the LR-GAs.

Considering the serious coal and rock dynamic disasters around the main slip plane called F16 in the coal mining area) of Henan Yima (China) thrust nappe structure, the mechanical genesis of the Yima thrust nappe structure was studied comprehensively using geomechanics, fault mechanics, elastic mechanics, and Coulomb’s law of friction. First, using the centrifugal inertia force of Earth’s rotation as a source, a mechanical model of N-S compression superimposed with W-E reverse torsion was established to explain the formation of the early Yima coal basin and Jurassic Yima Group coal measures. Second, an equation for the ultimate stress in the forming stage of F16 was derived using the plastic slip-line field theory and the parabolic Mohr failure criterion. Moreover, the distribution of ultimate stress and the geometric characteristics of the fault profile were obtained using the field model parameters. Finally, the stress field of F16 and the mechanical genesis of the large-scale reverse thrust sheet were discussed based on elastic mechanics theory and Coulomb’s law of friction. The results show that the tectonic framework of the early Yima coal basin and the formation pattern of Jurassic Yima Group coal measures given by the model are consistent with the in-situ explorations. The geometric characteristics of the fault profile obtained by numerical calculation can better reflect the shape of F16 in its forming stage, and the mechanical genesis of the large-scale reverse thrust sheet also concurred with the field situations. Thus, this work can provide a foundation for further studies on the genesis of the thrust nappe structure, the mechanism of rock bursts induced by F16, and the characteristics of the residual stress field in the Yima mining area.

Ningwu porphyrite-type iron deposits are located in Ningwu Mesozoic volcanic basin, which belongs to the middle and lower reaches of the Yangtze River metallogenic province. The volcanic rocks can be divided into Longwangshan, Dawangshan, Gushan and Niangniangshan Formations from early to late. All these volcanic rocks are rich in alkali, and show the similar patterns in rare earth element (REE) distribution. However, some differences can be found in the trace elements and REE patterns. The study of petrology and REE geochemical characteristics shows that these rocks are derived from the underplating of the lithospheric mantle and are contaminated by crustal materials, undergo AFC process during the magmatic evolution.

Polymetallic iron ore sulphate deposits of marine volcanic rock have been developed in the Fangniugou area, Jilin Province, China, but the division of volcanic ore-bearing strata has not been specifically elucidated and there is disagreement about the division. The sampling and SHRIMP U-Pb zircon dating of volcanic rock for Daheishan in the Fangniugou area and the northeast slope of the Duanjiadian were described. The volcanic rock formation period and recorded the volcanic events in the Daheishan mountains were systematically researched. Two samples of high-precision U-Pb zircon dating were used to represent the volcanic rock fomation period of the Late Silurian. The measured data reflect that multiple volcanic activities occurred during the Middle Silurian, Early Silurian, Middle Ordovician and Silurian, and Late Ordovician, probably matching volcanic events in the Songnan Basin identified from zircon dating. At the same time, it is confirmed that a controversial “conglomerate of Daheishan” did in fact develop in the Late Silurian, and those sections of both the Dazigou and Xinlitun-Taoshan with graptolite had been reversed.

To properly simulate hard rock with a high ratio of the uniaxial compressive strength to tensile strength (UCS/TS) and realistic strength-failure envelope, the rock deformation and mechanical characteristics were discussed in detail when the particle simulation method with the clump parallel-bond model (CPBM) was used to conduct a series of numerical experiments at the specimen scale. Meanwhile, the effects of the loading procedure and crack density on the mechanical behavior of a specimen, which was modeled by the particle simulation method with the CPBM, were investigated. The related numerical results have demonstrated that: 1) The uniaxial compressive strength (UCS), tensile strength (TS) and elastic modulus are overestimated when the conventional loading procedure is used in the particle simulation method with the CPBM; 2) The elastic modulus, strength and UCS/TS decrease, while Poisson ratio increases with the increase of the crack density in the particle simulation method with the CPBM; 3) The particle simulation method with the CPBM can be used to reproduce a high value of UCS/TS(>10), as well as a high friction angle and reasonable cohesion strength; 4) As the confining pressure increases, both the peak strength of the simulated specimen and the number of microscopic cracks increase, but the ratio of tensile cracks number to shear cracks number decreases in the particle simulation method with the CPBM; 5) Compared with the conventional parallel-bond model, the CPBM can be used to reproduce more accurate results for simulating the rock deformation and mechanical characteristics.

Based on the explicit finite element (FE) method and platform of ABAQUS, considering both the inhomogeneity of soils and concave-convex fluctuation of topography, a large-scale refined two-dimensional (2D) FE nonlinear analytical model for Fuzhou Basin was established. The peak ground motion acceleration (PGA) and focusing effect with depth were analyzed. Meanwhile, the results by wave propagation of one-dimensional (1D) layered medium equivalent linearization method were added for contrast. The results show that: 1) PGA at different depths are obviously amplified compared to the input ground motion, amplification effect of both funnel-shaped depression and upheaval areas (based on the shape of bedrock surface) present especially remarkable. The 2D results indicate that the PGA displays a non-monotonic decreasing with depth and a greater focusing effect of some particular layers, while the 1D results turn out that the PGA decreases with depth, except that PGA at few particular depth increases abruptly; 2) To the funnel-shaped depression areas, PGA amplification effect above 8 m depth shows relatively larger, to the upheaval areas, PGA amplification effect from 15 m to 25 m depth seems more significant. However, the regularities of the PGA amplification effect could hardly be found in the rest areas; 3) It appears a higher regression rate of PGA amplification coefficient with depth when under a smaller input motion; 4) The frequency spectral characteristic of input motion has noticeable effects on PGA amplification tendency.

The macro mechanical properties of materials with characteristics of large scale and complicated structural composition can be analyzed through its reconstructed meso-structures. In this work, the meso-structures of talus deposits that widely exist in the hydro-power engineering in the southwest of China were first reconstructed by small particles according to the in-situ photographs based on the self-adaptive PCNN digital image processing, and then numerical direct shear tests were carried out for studying the mechanical properties of talus deposits. Results indicate that the reconstructed meso-structures of talus deposits are more consistent with the actual situation because the self-adaptive PCNN digital image processing has a higher discrimination in the details of soil-rock segmentation. The existence and random distribution of rock blocks make the initial shear stiffness, the peak strength and the residual strength higher than those of the “pure soil” with particle size less than 1.25 cm apparently, but reduce the displacements required for the talus deposits reaching its peak shear strength. The increase of rock proportion causes a significant improvement in the internal friction angle of talus deposit, which to a certain degree leads to the characteristics of shear stress-displacement curves having a changing trend from the plastic strain softening deformation to the nonlinear strain hardening deformation, while an unconspicuous increase in cohesion. The uncertainty and heterogeneity of rock distributions cause the differences of rock proportion within shear zone, leading to a relatively strong fluctuation in peak strengths during the shear process, while movement features of rock blocks, such as translation, rotation and crossing, expand the scope of shear zone, increase the required shear force, and also directly lead to the misjudgment that the lower shear strength is obtained from the samples with high rock proportion. That, however, just explains the reason why the shear strength gained from a small amount of indoor test data is not consistent with engineering practice.

The potential role of formal structural optimization was investigated for designing foldable and deployable structures in this work. Shape-sizing nested optimization is a challenging design problem. Shape, represented by the lengths and relative angles of elements, is critical to achieving smooth deployment to a desired span, while the section profiles of each element must satisfy structural dynamic performances in each deploying state. Dynamic characteristics of deployable structures in the initial state, the final state and also the middle deploying states are all crucial to the structural dynamic performances. The shape was represented by the nodal coordinates and the profiles of cross sections were represented by the diameters and thicknesses. SQP (sequential quadratic programming) method was used to explore the design space and identify the minimum mass solutions that satisfy kinematic and structural dynamic constraints. The optimization model and methodology were tested on the case-study of a deployable pantograph. This strategy can be easily extended to design a wide range of deployable structures, including deployable antenna structures, foldable solar sails, expandable bridges and retractable gymnasium roofs.

Based on reasonable assumptions that simplified the calculational model, a simple and practical method was proposed to calculate the post-construction settlement of high-speed railway bridge pile foundation by using the Mesri creep model to describe the soil characteristics and the Mindlin-Geddes method considering pile diameter to calculate the vertical additional stress of pile bottom. A program named CPPS was designed for this method to calculate the post-construction settlement of a high-speed railway bridge pile foundation. The result indicates that the post-construction settlement in 100 years meets the requirements of the engineering specifications, and in the first two decades, the post-construction settlement is about 80% of its total settlement, while the settlement in the rest eighty years tends to be stable. Compared with the measured settlement after laying railway tracks, the calculational result is closed to that of the measured, and the results are conservative with a high computational accuracy. It is noted that the method can be used to calculate the post-construction settlement for the preliminary design of high-speed railway bridge pile foundation.

Based on reliability theory, a general method for the optimization design of piles subjected to horizontal loads is presented. This method takes into consideration various uncertainties caused by pile installation, variability of geotechnical materials from one location to another, and so on. It also deals with behavior and side constraints specified by standard specifications for piles. To more accurately solve the optimization design model, the first order reliability method is employed. The results from the numerical example indicate that the target reliability index has significant influence on design parameters. In addition, the optimization weight increases with the target reliability index. Especially when the target reliability index is relatively large, the target reliability index has significant influence on design weight of piles.

The objective of this work is to obtain the seismic safety coefficient and fracture surface and proceed with the seismic safety evaluation for the rock mass or soil mass surrounding a tunnel, and the limitation of evaluating seismic stability is considered using the pseudo-static strength reduction. By using the finite element software ANSYS and the strength reduction method, new methods of seismic safety evaluation for the rock mass or soil mass surrounding a tunnel are put forward, such as the dynamic finite element static shear strength reduction method and dynamic finite element shear strength reduction method. In order to prove the feasibility of the proposed methods, the results of numerical examples are compared with that of the pseudo-static strength reduction method. The results show that 1) the two methods are both feasible, and the plastic zone first appears near the bottom corners; 2) the safety factor of new method II is smaller than that of new method I but generally, and the difference is very small. Therefore, in order to ensure the safety of the structure, two new methods are proposed to evaluate the seismic stability of the rock mass or soil mass surrounding a tunnel. A theoretical basis is provided for the seismic stability of the rock mass or soil mass and the lining surrounding a tunnel and also provided for the engineering application.