The mechanical and microstructural properties as well as crystallographic textures of asymmetrically rolled low carbon steel were studied. The modelling of plastic deformation was carried out in two scales: in the macro-scale, using the finite elements method, and in the crystallographic scale, using the polycrystalline deformation model. The internal stress distribution in the rolling gap was calculated using the finite elements method and these stresses were then applied to the polycrystalline elasto-plastic deformation model. Selected mechanical properties, namely residual stress distribution, deformation work, applied force and torques, and bend amplitude, were calculated. The diffraction measurements, X-ray and electron backscatter diffraction, enabled the examination of texture heterogeneity and selected microstructure characteristics. The predicted textures agree well with those determined experimentally. The plastic anisotropy of cold rolled ferritic steel samples, connected with texture, was expressed by Lankford coefficient.

Effect of quenching process on the microstructure and mechanical properties of a kind of seamless tubes of steel 28CrMnMoV was investigated. Then, an investigation on the influence of two different quenching processes on the ductile-brittle transition behavior of this steel was undertaken. The ductile-brittle transition temperatures of the steel by two different quenching processes were also determined. The results show that a good combination of mechanical properties can be obtained through austenitizing experimental steel at 800 °C or 890 °C followed by tempering at 630 °C. Ductile-to-brittle transition temperature of 28CrMnMoV steel austenitized at 800 °C followed by tempering at 640 °C is about −73 °C, which is much lower than the value −37 °C when the steel was austenitized at 890°C and then tempered at 650 °C. This indicates that subcritical quenching process could decrease largely the ductile-to-brittle transition temperature of 28CrMnMoV steel.

Al₂O₃-SiO₂ system ceramic matrix composites with different volume fractions (10%–60%) of hexagonal BN particulates (BN_p) were prepared by hot-press sintering technique. Phase components, microstructure, mechanical properties and plasma erosion resistance were also investigated. With the increase of h-BN_p content, relative density and Vickers’ hardness of the composite ceramics decrease, while the flexural strength, elastic modulus and fracture toughness increase and then decrease. The plasma erosion resistance linearly deteriorated with the increase of BN_p content which is mainly determined by the density, crystal structure and atomic number of the elements.

The most remarkable effect in spinel ferrites is the strong dependence of properties on the state of structural disorder and, in particular, on the cation distribution. The structural characterization of a Co-Zn ferrite nanoparticle sample was reported which prepared by wet chemical co-precipitation method. The samples were sintered at three different temperatures viz. 650 °C, 850 °C and 1 050 °C for 12 h. The structural details like: lattice constant and distribution of cations in the tetrahedral and octahedral interstitial voids have been deduced through X-ray diffraction (XRD) data analysis. Lattice constant was found to increase with the increase in Zn²⁺ ions and sintering temperature. Theoretical intensity ratios of (220), (400), (440) planes were considered, as these reflections are sensitive to cations on the A and B sites. Close agreement of the theoretical intensity ratio with the intensity ratio observed from XRD pattern supports the occupancy of Zn²⁺ ions and Co²⁺ ions on the octahedral and tetrahedral sites, respectively.

Stable and monodispersed silver nanoparticles were produced through a mild, convenient, one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer. The surface plasma band transition was monitored along with time in the reaction mixture for three sets of experiments by ultraviolet-visible spectroscopy. Analysis of the data with the Avrami equation yielded n exponent with values between 0.5 and 1.5, demonstrating three-dimensional heterogeneous nucleation and diffusion-controlled growth, accompanied by soft impingement effect. XRD and TEM analyses show a softly agglomerated polycrystalline state and a nearly spherical morphology (<50 nm) of nanoparticles. The FT-IR result indicates that the PAA molecular structure could be hardly influenced by the formation of nanoparticles.

In order to obtain better carbonation effect, extraction behavior of slag batch is necessary to study. Relevant parameters like selective extraction yield were originally discussed. The relationship between selective extraction yield and conversion ratio was systemically focused on. The results show that alkaline earth metal conversion ratio is changed with leaching time and NH₄Cl concentration by first order exponential, and the maximum conversion for calcium keeps about 68% at 120 min in 0.4 mol/L NH₄Cl solution, while leaching temperature and particle size have a linear effect on conversion ratio. Selective extraction yield of calcium is more than 93%, and the value of Mg is less than 5%. Apparent layer bands of silicon and calcium appear in the surface area through morphology detection of slag after leaching, and the case for 38–75 μm slag batch is more obvious than 75–150 μm slag and slag with larger particle size when leaching in 0.4 mol /L NH₄Cl solution for 90 min at 60 °C.

The streaming potential of poly(vinyl butyral) (PVB) hollow fiber membrane was studied in different electrolyte solutions (including NaCl, KCl, CaCl₂ and MgCl₂), the effects of ionic strength, ion valence and pH value on the streaming potential (SP) of the membrane were investigated. The zeta potentials and surface charge densities of the membrane were estimated on the basis of Helmholtz-Smoluchowski equation and Gouy-Chapmann theory. The results show that the PVB membrane has a weak negative charge due to the specific adsorption of ions. Moreover, the streaming potential, the zeta potential and the surface charge density of the membrane depend strongly on the salt concentration and the type and valence of ions. The iso-electric point (IEP) of the PVB membrane is around 3.0 in the monovalent media (NaCl and KCl) and 3.5 in divalent electrolytes (CaCl₂ and MgCl₂). A few retentions were obtained for PVB membrane in low concentration solutions. This result verifies that the negative charged membrane surface can reject inorganic solutes by means of electrostatic repulsion effect even though the size of membrane pores is much larger than the size of salts.

Electro-catalysts Fe₂O₃ compounded by ZnO were prepared by a sol-gel method, which were titled as Fe₂O₃-ZnO. Electro-catalysts Fe₂O₃-ZnO loading on the bamboo charcoal was titled as Fe₂O₃-ZnO/C. The catalytic materials were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The obtained catalysts were assembled to three-dimensional electrodes to degradation of chlorinated organic in paper wastewater. And the performance tests show that three-dimensional electrodes have high activities for degradation of chlorinated organic in paper wastewater. There are many factors affecting the electro-catalytic performances of the three-dimensional electrodes. And the orthogonal experiment results show that the optimum operating condition is as follows: the calcination time of the catalysts 2 h, the mass ratio of Fe to Zn 4:1, the voltage 12 V, the mass of the catalytic materials 6 g, the value of pH 9, and the treating time 2.5 h. Under these conditions, the optimum removal efficiency of chlorinated organics in paper wastewater is 47.58%.

The most important grinding processes were realized in a single pass of the grinding wheel, such as continuous path controlled grinding (CPCG/Peelgrinding/HSP), CPCG with reduced contact of the grinding wheel (Quickpoint), single-pass longitudinal internal grinding, creep feed grinding (CFG), longitudinal cylindrical grinding with grinding wheels made of conventional abrasive materials and longitudinal internal cylindrical grinding using grinding wheels with zone-diversified structure.

The system considered in this work consists of a cylinder which is controlled by a pair of three-way servo valves rather than a four-way one. Therefore, the cylinder output stiffness is independently controllable of the output force. A discontinuous projection based adaptive robust controller (ARC) was constructed to achieve high-accuracy output force trajectory tracking for the system. In ARC, on-line parameter adaptation method was adopted to reduce the extent of parametric uncertainties due to the variation of friction parameters, and sliding mode control method was utilized to attenuate the effects of parameter estimation errors, unmodelled dynamics and disturbance. Furthermore, output stiffness maximization/minimization was introduced to fulfill the requirement of many robotic applications. Extensive experimental results were presented to illustrate the effectiveness and the achievable performance of the proposed scheme. For tracking a 0.5 Hz sinusoidal trajectory, maximum tracking error is 4.1 N and average tracking error is 2.2 N. Meanwhile, the output stiffness can be made and maintained near its maximum/minimum.

The dynamic model of a novel electric power steering (EPS) system integrated with active front steering function (the novel EPS system) is built. The concepts and quantitative expressions of the steering road feel, steering sensibility, and steering operation stability are introduced. Based on quality engineering theory, the optimization algorithm is proposed by integrating the Monte Carlo descriptive sampling, elitist non-dominated sorting genetic algorithm (NSGA-II) and 6-sigma design method. With the steering road feel and the steering portability as optimization targets, the system parameters are optimized by the proposed optimization algorithm. The simulation results show that the system optimized based on quality engineering theory can improve the steering road feel, guarantee steering stability and steering portability and thus provide a theoretical basis for the design and optimization of the novel electric power steering system.

Particle-in-cell (PIC) method has got much benefits from GPU-accelerated heterogeneous systems. However, the performance of PIC is constrained by the interpolation operations in the weighting process on GPU (graphic processing unit). Aiming at this problem, a fast weighting method for PIC simulation on GPU-accelerated systems was proposed to avoid the atomic memory operations during the weighting process. The method was implemented by taking advantage of GPU’s thread synchronization mechanism and dividing the problem space properly. Moreover, software managed shared memory on the GPU was employed to buffer the intermediate data. The experimental results show that the method achieves speedups up to 3.5 times compared to previous works, and runs 20.08 times faster on one NVIDIA Tesla M2090 GPU compared to a single core of Intel Xeon X5670 CPU.

On the basis of the theoretical analysis of a single-machine infinite-bus (SMIB), using the modified linearized Phillips-Heffron model installed with unified power flow controller (UPFC), the potential of the UPFC supplementary controller to enhance the dynamic stability of a power system is evaluated by measuring the electromechanical controllability through singular value decomposition (SVD) analysis. This controller is tuned to simultaneously shift the undamped electromechanical modes to a prescribed zone in the s-plane. The problem of robust UPFC based damping controller is formulated as an optimization problem according to the eigenvalue-based multi-objective function comprising the damping factor, and the damping ratio of the undamped electromechanical modes to be solved using gravitational search algorithm (GSA) that has a strong ability to find the most optimistic results. The different loading conditions are simulated on a SMIB system and the rotor speed deviation, internal voltage deviation, DC voltage deviation and electrical power deviation responses are studied with the effect of this flexible AC transmission systems (FACTS) controller. The results reveal that the tuned GSA based UPFC controller using the proposed multi-objective function has an excellent capability in damping power system with low frequency oscillations and greatly enhances the dynamic stability of the power systems.

A disturbance decoupled fault diagnosis strategy is proposed. This disturbance decoupled fault diagnosis is both robust to disturbances and sensitive to sensor faults of magnetic levitation control system. First, a robust controller based on a novel disturbance observer is devised to improve the disturbance attenuation ability, which greatly enhances the robustness of the system. Second, a fault reconstruction technique with adaptive method is presented, along with a strict verification for guaranteeing the robustness of fault. This fault reconstruction technique provides an accurate sensor fault reconstruction. From the results of simulation and experiments conducted on the CMS-04 maglev train, the integrated strategy is robust to model uncertainties of the system and the fault reconstruction algorithm is able to reconstruct the dynamic uncertain faults.

How to reduce the energy consumption powered mainly by battery to prolong the standby time is one of the crucial issues for IEEE 802.16e wireless MANs. By predicting the next downlink inter-packet arrival time, three traffic-prediction-assisted power saving mechanisms based on P-PSCI, i.e., PSCI-PFD, PSCI-ED and PSCI-LD, were proposed. In addition, the corresponding adjustment strategies for P-PSCI were also presented when there were uplink packets to be transmitted during sleep mode. Simulation results reveal that compared with the sleep mode algorithm recommended by IEEE 802.16e, the proposed mechanism P-PSCI can improve both energy efficiency and packet delay for IEEE 802.16e due to the consideration of the traffic characteristics and rate changes. Moreover, the results also demonstrate that PSCI-PFD (a=−2) significantly outperforms PSCI-ED, PSCI-LD, and the standard sleep mode in IEEE 802.16e is in terms of energy efficiency and packet delay.

A cost-based selective maintenance decision-making method was presented. The purpose of this method was to find an optimal choice of maintenance actions to be performed on a selected group of machines for manufacturing systems. The arithmetic reduction of intensity model was introduced to describe the influence on machine failure intensity by different maintenance actions (preventive maintenance, minimal repair and overhaul). In the meantime, a resolution algorithm combining the greedy heuristic rules with genetic algorithm was provided. Finally, a case study of the maintenance decision-making problem of automobile workshop was given. Furthermore, the case study demonstrates the practicability of this method.

In order to solve reliability-redundancy allocation problems more effectively, a new hybrid algorithm named CDEPSO is proposed in this work, which combines particle swarm optimization (PSO) with differential evolution (DE) and a new chaotic local search. In the CDEPSO algorithm, DE provides its best solution to PSO if the best solution obtained by DE is better than that by PSO, while the best solution in the PSO is performed by chaotic local search. To investigate the performance of CDEPSO, four typical reliability-redundancy allocation problems were solved and the results indicate that the convergence speed and robustness of CDEPSO is better than those of PSO and CPSO (a hybrid algorithm which only combines PSO with chaotic local search). And, compared with the other six improved meta-heuristics, CDEPSO also exhibits more robust performance. In addition, a new performance was proposed to more fairly compare CDEPSO with the same six improved meta-heuristics, and CDEPSO algorithm is the best in solving these problems.

Data deduplication, as a compression method, has been widely used in most backup systems to improve bandwidth and space efficiency. As data exploded to be backed up, two main challenges in data deduplication are the CPU-intensive chunking and hashing works and the I/O intensive disk-index access latency. However, CPU-intensive works have been vastly parallelized and speeded up by multi-core and many-core processors; the I/O latency is likely becoming the bottleneck in data deduplication. To alleviate the challenge of I/O latency in multi-core systems, multi-threaded deduplication (Multi-Dedup) architecture was proposed. The main idea of Multi-Dedup was using parallel deduplication threads to hide the I/O latency. A prefix based concurrent index was designed to maintain the internal consistency of the deduplication index with low synchronization overhead. On the other hand, a collisionless cache array was also designed to preserve locality and similarity within the parallel threads. In various real-world datasets experiments, Multi-Dedup achieves 3–5 times performance improvements incorporating with locality-based ChunkStash and local-similarity based SiLo methods. In addition, Multi-Dedup has dramatically decreased the synchronization overhead and achieves 1.5–2 times performance improvements comparing to traditional lock-based synchronization methods.

For the accurate description of aerodynamic characteristics for aircraft, a wavelet neural network (WNN) aerodynamic modeling method from flight data, based on improved particle swarm optimization (PSO) algorithm with information sharing strategy and velocity disturbance operator, is proposed. In improved PSO algorithm, an information sharing strategy is used to avoid the premature convergence as much as possible; the velocity disturbance operator is adopted to jump out of this position once falling into the premature convergence. Simulations on lateral and longitudinal aerodynamic modeling for ATTAS (advanced technologies testing aircraft system) indicate that the proposed method can achieve the accuracy improvement of an order of magnitude compared with SPSO-WNN, and can converge to a satisfactory precision by only 60–120 iterations in contrast to SPSO-WNN with 6 times precocities in 200 times repetitive experiments using Morlet and Mexican hat wavelet functions. Furthermore, it is proved that the proposed method is feasible and effective for aerodynamic modeling from flight data.

Froth image could strongly indicate the production status in mineral flotation process. Considering low contrast and sensitivity to noises and illumination of froth images in flotation cells, an improved image enhancement algorithm based on nonsubsampled contourlet transform (NSCT) and multiscale Retinex algorithm has been proposed. Nonsubsampled contourlet transform was firstly adopted to decompose the flotation froth images, ensure signals invariance and avoid the blurring edge. Secondly, a multiscale Retinex algorithm was used to enhance the lower frequency image and improve the brightness uniformity. Adaptive classification method based on Bayes atrophy threshold was proposed to eliminate noise, preserve strong edges, and enhance weak edges of band-pass sub-band images. Experiment shows that the proposed method could enhance the edge, contour, details and curb noise, and improve visual effects. Under-segmentation caused by noise and blurring edge has been solved, which lays a foundation for extracting foamy morphological flotation froth and analyzing grade.

The objective of this work was to determine the location of emergency material warehouses. For the site selection problem of emergency material warehouses, the triangular fuzzy numbers are respectively demand of the demand node, the distance between the warehouse and demand node and the cost of the warehouse, a bi-objective programming model was established with minimum total cost of the system and minimum distance between the selected emergency material warehouses and the demand node. Using the theories of fuzzy numbers, the fuzzy programming model was transformed into a determinate bi-objective mixed integer programming model and a heuristic algorithm for this model was designed. Then, the algorithm was proven to be feasible and effective through a numerical example. Analysis results show that the location of emergency material warehouse depends heavily on the values of degree α and weight w₁. Accurate information of a certain emergency activity should be collected before making the decision.

The thermal conduction behavior of the three-dimensional axisymmetric functionally graded circular plate was studied under thermal loads on its top and bottom surfaces. Material properties were taken to be arbitrary distribution functions of the thickness. A temperature function that satisfies thermal boundary conditions at the edges and the variable separation method were used to reduce equation governing the steady state heat conduction to an ordinary differential equation (ODE) in the thickness coordinate which was solved analytically. Next, resulting variable coefficients ODE due to arbitrary distribution of material properties along thickness coordinate was also solved by the Peano-Baker series. Some numerical examples were given to demonstrate the accuracy, efficiency of the present model, and to investigate the influence of different distributions of material properties on the temperature field. The numerical results confirm that the influence of different material distributions, gradient indices and thickness of plate to temperature field in plate can not be ignored.

Reburning was applied to Polish automatic coal-fired retort boiler (25 kW). The use of bio-syngas reduced NO_x emissions from the boiler by over 25%, below the significant level of 200 mg/m³. Reburning was carried out using an integrated system consisting of the boiler and a fixed-bed 60 kW (GazEla) gasification reactor. The process gas was continuously introduced above the coal burner of the boiler. The process parameters of the boiler and the gasifier were also measured and compared with the other units. Characteristic NO_x emissions from automatic and manually operated boilers were also presented.

In the view of the problems existing in horizontal well, such as sand depositing and cleaning difficulty of borehole, a technology with rotating jet suitable to resolution of the problems was presented. Based on liquid-solid two-phase flow theory, the analyses on the sand movement law and the swirling field influential factors were conducted. Results show that: 1) With the increasing of displacement in horizontal section annulus, swirling field strength increases, and when the displacement is constant, the closer from the nozzle, the stronger the swirling field strength is; 2) Head rotating speed and liquid viscosity have little influence on the swirling field strength, but the sand-carrying rate of fluid can increase by increasing liquid viscosity in a certain range; 3) Rotating the string and reducing its eccentricity in annulus are conducive for sand migration in the annulus; 4) The sand can be suspended and accelerated again and the swirling field strength is enhanced by the helix agitator. Hence, the research results provide the theoretical basis for the design and application of rotating jet tool.

Soil contaminated with typical heavy metals (Pb, Cd, Cu, and Zn) was remedied by using the polymeric aluminum salt coagulants including polyaluminum chloride (PAC) and polyaluminum sulfate (PAS). The remediation efficiencies are influenced by reaction time, water amount, and dosage of remediation agent. The optimal remediation conditions are as follows: 6 h of reaction time, 1 kg/kg of water addition amount, and 0.25 kg/kg of remediation agent dosage. After PAC addition, the remediation efficiencies of diethylenetriamine-pentaacetic acid (DTPA)-extractable Pb, Cd, Cu, and Zn reach 88.3%, 85.1%, 85.4%, and 73.7%, respectively; and those for PAS are 89.7%, 88.7%, 83.5%, and 72.6%, respectively. The main remediation mechanism of the polymeric aluminum salt may contribute to the ionization and hydrolysis of PAC and PAS. H⁺ released from ionization of polymeric aluminum salt can cause the leaching of heavy metals, while the multinuclear complex produced from hydrolysis may result in the immobilization of heavy metals. For PAC, the immobilization of heavy metals is the main remediation process. For PAS, both leaching and immobilization are involved in the remediation process of heavy metals.

Bioflotation represents one of the growing trends to enhance the selectivity of conventional flotation processes. It utilizes the micro-organisms to replace or to interact with the chemical reagents to increase the gap between surface properties of similar minerals and to enhance the separation selectivity. In this work, dolomite-phosphate separation was investigated using amphoteric collector (dodecyl-N-carboxyethyl-N-hyroxyethyl-imidazoline) in presence of bacteria. Two types of bacteria, Corynebacterium-diphtheriae-intermedius (CDI), and Pseudomonas aeruginosa (PA), were used. The collector-bacteria interaction was characterized by Fourier transform infra-red (FTIR), frothing height and Zeta potential. The results show that the collector-bacteria interaction improves the flotation selectivity. Although, the PA positively affects the separation results, the CDI cannot lower the MgO to less than 1%. A phosphate content of 0.7% MgO and 31.77% P₂O₅ with a recovery of 68% at pH 11, 3.0 kg/t amphoteric collector, 4×10⁷ cells of PA is obtained.

The particle simulation method is used to solve free-surface slurry flow problems that may be encountered in several scientific and engineering fields. The main idea behind the use of the particle simulation method is to treat granular or other materials as an assembly of many particles. Compared with the continuum-mechanics-based numerical methods such as the finite element and finite volume methods, the movement of each particle is accurately described in the particle simulation method so that the free surface of a slurry flow problem can be automatically obtained. The major advantage of using the particle simulation method is that only a simple numerical algorithm is needed to solve the governing equation of a particle simulation system. For the purpose of illustrating how to use the particle simulation method to solve free-surface flow problems, three examples involving slurry flow on three different types of river beds have been considered. The related particle simulation results obtained from these three examples have demonstrated that: 1) The particle simulation method is a promising and useful method for solving free-surface flow problems encountered in both the scientific and engineering fields; 2) The shape and irregular roughness of a river bed can have a significant effect on the free surface morphologies of slurry flow when it passes through the river bed.

Anisotropic strength and deformability of the rock mass with non-persistent joints are governed by cracking process of the rock bridges. The dependence of cracking process of jointed rock masses on the two important geometrical parameters, joint orientation and joint persistence, was studied systematically by carrying out a series of uniaxial compression tests on gypsum specimens with regularly arranged multiple parallel pre-existing joints. According to crack position, mechanism and temporal sequence, seven types of crack initiations and sixteen types of crack coalescences, were identified. It was observed that both tensile cracks and shear cracks can emanate from the pre-existing joints as well as the matrix. Vertical joints were included and coplanar tensile cracks initiation and coalescence were observed accordingly. For specimen with joint inclination angle β=75°, it was found that collinear joints can be linked not only by coplanar shear cracks but also by mixed tensile-shear cracks, and that a pair of them can form a small rotation block. Seven failure modes, including axial cleavage, crushing, crushing and rotation of new blocks, stepped failure, stepped failure and rotation of new blocks, shear failure along a single plane and shear failure along multiple planes, were observed. These modes shift gradually in accordance with the combined variation of joint orientation and joint persistence. It is concluded that cracking process and failure modes are more strongly affected by joint orientation than by joint persistence, especially when joint inclination angle is larger than 45°. Finally, variations of macroscopic mechanical behaviors with the two geometrical parameters, such as patterns of the complete axial stress-axial strain curves, peak strength and elastic modulus, are summarized and their mechanisms are successfully explained according to their different cracking process.

Effective carrier system comprises carrier beds which transport hydrocarbons. The spatial and temporal effectiveness of carrier system is identified according to the relevance of hydrocarbon show, hydrocarbon inclusion and sealing ability of fault to hydrocarbons distribution, together with matching relation of activity history of fault and hydrocarbon generation history of source rock. On the basis of the above considerations, transporting ability of effective carrier system can be evaluated using parameters such as fluid potential, porosity and permeability, spatial coefficient of effective pathway as well as activity rate of fault. Additionally, a new concept of “transporting threshold porosity” was proposed. Five styles of effective carrier systems were established in Gaoyou Sag, displaying either layered or zonal distribution characteristics, and transporting time ranges from the sedimentary time of E₂d₂ to early stage of sanduo uplift. Effective carrier systems can be described to be lowly-efficient and highly-efficient. Major faults (convex or steep fault plane) with activity rate greater than 20 m/Ma and structure ridges of sand layers with spatial coefficient of effective pathway greater than 25% are defined to be highly-efficient carrier beds. Hydrocarbons are concentrated around high-efficient carrier beds and E₁f traps of northern shanian area are predicted to have great potential.

From the outcrops in the Yaomoshan and Hongyanchi sections, oil shales, deep dark mudstones or black mudstones with better organic richness were found. Through the analysis of the samples in the organic petrology method, the microscope features of the sedimentary organic matter were studied. The results indicate that three types of kerogens present in the measured samples. Kerogen type I consists of the laminate algainite, abundant sporinite and only little content of cutinite, which can mainly generate oil. The generation hydrocarbon components of the type II kerogen are dominated by the sporinite, cutinite and little the exinite debris. The type III kerogen is comprised of the sporinite and debris of the exinite with some components of gas generation. Through the analysis of the experiments, the organic kerogen of the Lucaogou formation is mostly comprised of the type I, partially type II, and particularly type III. In Hongyanchi formation, the organic type is mixed by the types II and III. The plot of the (S₁+S₂) or TOC value and the content of exinite show two trends. From the evolution of burial and the Permian source rocks in Changji Depression, the Permian formation source rock has ended the generation of hydrocarbon. A significant difference in constituents of the organic macerals among three kerogens in these samples leads to the distinction of the potential hydrocarbon generation. The Lucaogou formation for kerogen type I has better potential hydrocarbon generation. It can reach the oil peak with R_o ratio of 0.9%. For the kerogen II, the oil peak of the source rocks comes late with the R_o ratio of 1.0% with less quantity of the generation hydrocarbon than the kerogen I. For type III, it can mainly generate gas and reach the gas peak with the R_o ratio of 1.3%. In a word, the Lucaogou formation and Hongyanchi formation source rocks with high organic richness in Permian source rocks have well exploration prospects.

Experimental evidence has indicated that clay exhibits strain-softening response under undrained compression following anisotropic consolidation. The purpose of this work was to propose a modeling method under critical state theory of soil mechanics. Based on experimental data on different types of clay, a simple double-surface model was developed considering explicitly the location of critical state by incorporating the density state into constitutive equations. The model was then used to simulate undrained triaxial compression tests performed on isotropically and anisotropically consolidated samples with different stress ratios. The predictions were compared with experimental results. All simulations demonstrate that the proposed approach is capable of describing the drained and undrained compression behaviors following isotropic and anisotropic consolidations.

In recent years, a new type of foundation named composite piled raft foundation (also called long-short composite piled raft) has been developed. Where designing shallow foundations would mean unacceptable settlement, or other environmental risks exist which could impair the structure in the future, composite piled raft foundations could be used. Finite element method was applied to study the behavior of this type of foundation subjected to vertical loading. In order to determine an optimal pile arrangement pattern which yields the minimum settlement, various pile arrangements under different vertical stress levels were investigated. Results show that with increasing the vertical stress on the raft, the effectiveness of the arrangements of short and long piles become more visible. In addition, a new factor named “composite piled raft efficiency” (CPRE) has been defined which determines the efficiency of long-short piles arrangement in a composite piled raft foundation. This factor will increase when short piles take more axial stresses and long piles take less axial stresses. In addition, it is found that the changes in settlements for different long-short piles arrangement are in a well agreement with changes in values of CPRE ratio. Thus, CPRE ratio can be used as a factor to determine the efficiency of piles arrangements in composite piled raft foundation from the view point of reducing raft settlements.

Combining mathematical morphology (MM), nonparametric and nonlinear model, a novel approach for predicting slope displacement was developed to improve the prediction accuracy. A parallel-composed morphological filter with multiple structure elements was designed to process measured displacement time series with adaptive multi-scale decoupling. Whereafter, functional-coefficient auto regressive (FAR) models were established for the random subsequences. Meanwhile, the trend subsequence was processed by least squares support vector machine (LSSVM) algorithm. Finally, extrapolation results obtained were superposed to get the ultimate prediction result. Case study and comparative analysis demonstrate that the presented method can optimize training samples and show a good nonlinear predicting performance with low risk of choosing wrong algorithms. Mean absolute percentage error (MAPE) and root mean square error (RMSE) of the MM-FAR&LSSVM predicting results are as low as 1.670% and 0.172 mm, respectively, which means that the prediction accuracy are improved significantly.

In order to overcome the wide crack of ordinary reinforced concrete (RC) at service stage which affects the service performance and durability of structures, a kind of concrete structure with skin textile reinforcement is proposed, namely a part of concrete cover of RC members is replaced by textile reinforced concrete (TRC). The flexural experimental results indicate that when the reinforcement ratios of steel bars are constant, compared with control beams, the average value of crack loads of the beams, whose reinforcement ratios of textile are 0.018%, 0.036% and 0.055%, increases by 15.5%, 20.4% and 31.1%, respectively, the average value of yield loads respectively increases by 12.5%, 19.9% and 21.1% and the average value of ultimate loads respectively increases by 8.5%, 26.0% and 44.0%, respectively. Considerable reduction in cracks width and spacing is observed for specimens with a TRC layer, and when the beams yield, the maximum crack width of the beam with textile stuck no sand and the beam with textile stuck sand is reduced by around 60% and 70%, respectively. Surface treatment of textile and mixing polypropylene fiber into fine grained concrete contribute to enhance the service performance of the flexural element. Embedding U-shaped hoop has almost no effect on the control of the crack width. Finally, the calculation method of ultimate bearing capacity of this flexural component with TRC layer was presented. Comparison between the calculated and the experimental values reveals satisfactory agreement, and the maximum error is no more than 6%.

A unified semi-analytical solution is presented for elastic-plastic stress of a deep circular hydraulic tunnel with support yielding under plane strain conditions. The rock mass is assumed to be elastic-perfectly plastic and governed by the unified strength theory (UST). Different major principal stresses in different engineering situations and different support yielding conditions are both considered. The unified solution obtained in this work is a series of results, rather than one specific solution, hence it is suitable for a wide range of rock masses. In addition, parametric study is conducted to investigate the effect of intermediate principal stress. The result shows the major principal stress should be rationally chosen according to different engineering conditions. Finally, the applicability of the unified solution is discussed according to the critical pressures.

A new calculation method for axial load capacity of separated concrete-filled steel tubes based on limit equilibrium theory was proposed, which took into account the decrease of confinement effect by steel tube and the non-uniform distribution of ultimate stress in cored concrete. The accuracy of the analytical result is validated through running the numerical result by finite element method (FEM) and experimental data as well. The influences of the key parameters on the load capacity of the concrete-filled steel tube (CFST) was studied, including the separation ratio, concrete compressive strength, and steel strength. The results indicate that the load capacity of the tube increases with concrete strength and steel strength under the separation ratio less than 4%, while decreases with a higher separation ratio improved.

An innovative approach for the identification of cracks from the dynamic responses of girder bridges was proposed. One of the key steps of the approach was to transform the dynamical responses into the equivalent static quantities by integrating the excitation and response signals over time. A sliding-window least-squares curve fitting technique was then utilized to fit a cubic curve for a short segment of the girder. The moment coefficient of the cubic curve can be used to detect the locations of multiple cracks along a girder bridge. To validate the proposed method, prismatic girder bridges with multiple cracks of various depths were analyzed. Sensitivity analysis was conducted on various effects of crack depth, moving window width, noise level, bridge discretization, and load condition. Numerical results demonstrate that the proposed method can accurately detect cracks in a simply-supported or continuous girder bridges, the five-point equally weighted algorithm is recommended for practical applications, the spacing of two discernable cracks is equal to the window length, and the identified results are insensitive to noise due to integration of the initial data.

A new finite element model for single-layered strand was investigated for accurate and efficient mechanical behavior analysis. Mathematical model was created by sectional path-nodes sweeping and dynamic node-beam mapping. Geometric relations between nodes in center core wire and helical wires were deduced in tension and bending incorporating material elasticity theory and deformation geometrical compatibility. Based on Timoshenko beam theory, strand of a pitch length was modeled with specific material, geometric parameters and synthesized constraint equations defined in ANSYS software, and predetermined load cases were performed. The obtained results show that discrepancies between suggested method and Costello theory do not exceed 1.51% in tension and 6.21% in bending, which verifies the correctness and accuracy of the suggested finite element model in predicting mechanical behavior of single-layered wire strand.

A novel conditional cell transmission model (CCTM) is a potential simulation tool because it accommodates all traffic conditions from light condition to oversaturated condition. To test the performance of the CCTM, a series of experiments for sensitivity analysis were designed and performed for a multilane, two-way, three-signal sample network. Experiment 1 shows that the model is performed in a logical and expected manner with variations in traffic demand with time and direction. Experiment 2 shows when the possibility of the occurrence of a useful gap increases to 60% and 100%, the delays in left turns decrease by 5% and 15%, respectively. In Experiment 3, comparing the possibility of a conditional cell of 0 with 100%, delay of left turn and delay of the entire network were underestimated by 58% and 11%, respectively. Hence, sensitivity analysis demonstrates that by reflecting local drivers’ behaviors properly, the CCTM provides an accurate representation of traffic flow in simulating oversaturated traffic conditions.