In this study, the electrochemical oxidation of reactive brilliant orange X-GN dye with a boron-doped diamond (BDD) anode was investigated. The BDD electrodes were deposited on the niobium (Nb) substrates by the hot filament chemical vapor deposition method. The effects of processing parameters, such as film thickness, current density, supporting electrolyte concentration, initial solution pH, solution temperature, and initial dye concentration, were evaluated following the variation in the degradation efficiency. The microstructure and the electrochemical property of BDD were characterized by scanning electron microscopy, Raman spectroscopy, and electrochemical workstation; and the degradation of X-GN was estimated using UV-Vis spectrophotometry. Further, the results indicated that the film thickness of BDD had a significant impact on the electrolysis of X-GN. After 3 h of treatment, 100% color and 63.2% total organic carbon removal was achieved under optimized experimental conditions: current density of 100 mA/cm², supporting electrolyte concentration of 0.05 mol/L, initial solution pH 3.08, and solution temperature of 60 °C.

A pulsed, picosecond Nd:YAG laser with a wavelength of 532 nm is used to texture the surface of grade 5 titanium alloy (Ti—6Al—4V) for minimizing its wear rate. The wear properties of the base samples and laser surface textured samples are analyzed by conducting wear tests under a sliding condition using pin-on-disk equipment. The wear tests are conducted based on the Box—Benhken design, and the interaction of the process parameters is analyzed using response surface methodology. The wear analysis is conducted by varying the load, rotating speed of the disc, and track diameter at room temperature with a sliding distance of 1500 m. The results demonstrate that the laser textured surfaces exhibited a lower coefficient of friction and good anti-wear properties as compared with the non-textured surfaces. A regression model is developed for the wear analysis of titanium alloy using the analysis of variance technique. It is also observed from the analysis that the applied load and sliding distance are the parameters that have the greatest effect on the wear behavior followed by the wear track diameter. The optimum operating conditions have been suggested based on the results obtained from the numerical optimization approach.

The effects of postweld heat treatment on the microstructure and metallurgical properties of a bronze—carbon steel (st37) explosively bonded interface were studied. Explosive welding was done under 1.5- and 2-mm standoff distances and different conditions of explosive charge. Samples were postweld heat treated for 4 and 16 h in the furnace at 250 °C and 500 °C and then air cooled. Laboratory studies using optical microscopy, scanning electron microscopy, and microhardness testing were used to evaluate the welded samples. Microstructural examinations showed that by increasing the standoff distance and the explosive charge, the interface of bronze to steel became wavier. The microhardness test result showed that the hardness of the samples was higher near the joint interface compared with other areas because of the intensive plastic deformation, which was caused by the explosion force. The results show that increasing the heat treatment temperature and time caused the intermetallic compounds’ layer thickness to increase, and, because of the higher diffusion of copper and tin, the iron amount in the intermetallic compounds decreased. Also, because of the increase in heat treatment temperature and time, internal stresses were released, and the interface hardness decreased.

Single grit grinding is the simplified model to abstract the macro scale grinding. Finite element analysis is a strong tool to study the physical fields during a single grit grinding process, compared to experimental research. Based on the dynamic mechanical behavior of 2Cr12Ni4Mo3VNbN steel and the mathematical statistics of abrasive grit, modeling of the single grit grinding process was conducted by using commercial software AdvantEdge. The validation experiment was designed to validate the correctness of the FEA model by contrast with grinding force. The validation result shows that the FEA model can well describe the single grit grinding process. Then the grinding force and multi-physics fields were studied by experimental and simulation results. It was found that both the normal and tangential grinding forces were linearly related to the cutting speed and cutting depth. The maximum temperature is located in the subsurface of the workpiece in front of the grit, while the maximum stress and strain are located under the grit tip. The strain rate can reach as high as about 10⁶ s⁻¹ during the single grit grinding,which is larger than other traditional machining operations.

In order to find out the impact of aluminum alloy hub replaced by the magnesium alloy hub on environment, the resource consumption, energy consumption and pollutant emission during hub production and their service life of the two types of hubs are investigated based on the life cycle assessment (LCA) theory. The results indicate that the adverse impact on environment can be effectively reduced by the application of magnesium alloy hubs. Compared with aluminum alloy hubs, the global warming potential (GWP) and human toxicity potential (HTP) are reduced by 39.6% and 24.0%, respectively. CO₂ is the main pollutant in the life cycles of the two kinds of hubs, which is generated throughout the whole life cycle including the fabrication process and the service life, while the pollutants of particles mainly come from the fabrication stage. Compared with the aluminum alloy hubs, the green effect brought by magnesium alloy hubs is mainly due to the reduction of fuel consumption caused by weight loss.

The forming performance of sheet metals in the deep-drawing process with ultrasonic vibrations can be improved by the surface effect between the sheet metal and the die. A sheet metal friction test with ultrasonic vibrations is performed to explore the cause of the surface effect. The frictional characteristics are investigated, and the corresponding friction expressions are established based on the contact mechanics and the elastic—plastic contact model for rough surfaces. Friction is caused by the elastic—plastic deformation of contacting asperities under normal loads. The actual contacting region between two surfaces increases with normal loads, whereas the normal distance decreases. The normal distance between the contacting surfaces is changed, asperities generate a tangential deformation with ultrasonic vibrations, and the friction coefficient is eventually altered. Ultrasonic vibrations are applied on a 40Cr steel punch at the frequency of 20 kHz and the amplitude of 4.2 μm. In the friction tests, the punch is perpendicular to the surface of the magnesium alloy AZ31B sheet metals and is sliding with a relative velocity of 1 mm/s. The test results show that the friction coefficient is decreased by approximately 40% and the theoretical values are in accordance with the test values; Ultrasonic vibrations can clearly reduce wear and improve the surface quality of parts.

Wollastonite glass ceramics were prepared using the reactive crystallization sintering method by mixing waste glass powders with gehlenite. The crystallization property, thermodynamics, and kinetics of the prepared wollastonite glass ceramics were determined by X-ray diffraction analysis, scanning electron microscopy, energy-dispersive spectroscopy, high-resolution transmission electron microscopy, and differential thermal analysis. Results showed that crystals of wollastonite and alumina could be found in the gehlenite through its reaction with silicon dioxide. The wollastonite crystals showed a lath shape with a certain length-to-diameter ratio. The crystals exhibited excellent bridging and reinforcing effects. In the crystallization process, the aluminum ions in gehlenite diffused into the glass and the silicon ions in the glass diffused into gehlenite. Consequently, the three-dimensional frame structure of gehlenite was partially damaged to form a chain-like wollastonite. The results of crystallization thermodynamics and kinetics indicated that crystallization reaction could occur spontaneously under a low temperature (1173 K), with 20 wt% gehlenite added as the reactive crystallization promoter. The crystallization activation energy was evaluated as 261.99 kJ/mol by using the Kissinger method. The compression strength of the wollastonite glass ceramic samples (7.5 cm×7.5 cm) reached 251 MPa.

A new reaction system to determine nonlinear chemical fingerprint (NCF) and its use in identification method based on double reaction system was researched. Panax ginsengs, such as ginseng, American ginseng and notoginseng were identified by the method. The NCFs of the three samples of Panax ginsengs were determined through two nonlinear chemical systems, namely system 1 consisting of sample components, H₂SO₄, MnSO₄, NaBrO₃, acetone and the new system, system 2 consisting of sample components, H₂SO₄, (NH₄)₄Ce(SO₄)₂, NaBrO₃ and citric acid. The comparison between the results determined through systems 1 and 2 shows that the speed to determine NCF through system 2 is much faster than that through system 1; for systems 1 and 2, the system similarities of the same kind of samples are ≥ 98.09% and 99.78%, respectively, while those of different kinds of samples are ≤ 63.04% and 86.34%, respectively. The results to identify the kinds of some samples by system similarity pattern show that both the accuracies of identification methods based on single system 1 and 2 are ≥ 95.6%, and the average values are 97.1% and 96.3%, respectively; the accuracy of the method based on double system is ≥ 97.8%, and the average accuracy is 99.3%. The accuracy of the method based on double system is higher than that based on any single system.

This paper mainly investigated the antimony recovery from antimony-bearing dusts through reduction roasting process after the dust firstly oxidation roasted. CO—CO₂ mixture gas was used as reducing agent, and the antimony-containing phase was reduced into Sb₄O₆, volatilized into smoke, and finally recovered through the cooling cylinder. The antimony recovery rate increased from 66.00 wt% to 73.81 wt% in temperature range of 650 to 800 °C, and decreased with temperature increased further to 900 °C due to the reduction of Sb₄O₆ to the nonvolatile Sb. Similarly, the CO partial pressure also played a double role in this test. Under optimized conditions of roasting temperature of 800 °C, CO partial pressure of 7.5 vol% and roasting time of 120 min, 98.40 wt% of arsenic removal rate and 80.40 wt% antimony recovery rate could be obtained. In addition, the “As₂O₃” product could be used for preparing ferric arsenate which realized the harmless treatment of it.

The synergistic inhibition effect of CeCl₃ (Ce) and serine (Ser) on the corrosion of carbon steel in a 3% NaCl solution was investigated by electrochemical methods and surface analysis. The results showed that both CeCl₃ and Ser, when used alone, had limited inhibition effect toward carbon steel corrosion in the 3% NaCl solution. In contrast, the combination of CeCl₃ with Ser produced a strong synergistic effect on the corrosion inhibition behavior of carbon steel, improving the inhibition efficiency significantly. The polarization curves showed that the mixture of CeCl₃ and Ser acts as a cationic-type inhibitor. Scanning electron microscopy and Fourier transform infrared spectroscopy showed that the synergistic inhibition effect was due to complex formation between the cerium ions and amino acid molecules.

Using fixed-bed reaction method and changing the gas composition and dust content, the influence of blast furnace top gas composition and dust on HCl removal with low temperature Ca-based antichlor was studied. It was found that, when the content of CO₂ in blast furnace top gas increased, the dechlorination efficiency was getting worse obviously; when the contents of CO and N₂ increased, the dechlorination efficiency was getting better to a certain extent; when the content of H₂ changed, the dechlorination efficiency got no significant change; as the content of dust increased, the dechlorination efficiency got better obviously when the content was less than 15 g/m³, but it would be got worse quickly when the content was more than 20 g/m³, and the best content was 15–20 g/m³; the suitable site of the process of dechlorination was after gravity dust collector and before bag dust collector.

Flotation tailings were successfully flocculated in the presence of cationic polyacrylamide and silica gel. The effects of various parameters such as polymer weight, charge density, and pH on the rate of flocculation were also investigated in the current study. The flocculation mechanism of the flocculant on tailings was investigated using zeta potential and Fourier transform infrared (FTIR) measurements. The results obtained reveal that 1) sodium silicate gel, used as a binder for the consolidation of tailings form primary flocs, acts as an anchor and the adsorption of polymer flocculant on these anchors results in the formation of larger flocs and, consequently, enhanced settling rate; 2) flocculation in the presence of silica gel and polymer has a faster settling rate than single-polymer flocculation owing to the mechanisms of charge neutralization and bridging as identified using zeta potential and FTIR measurements. A pilot level study was conducted to investigate the influence of processed water on the flotation of scheelite. The results show that the proposed tailing disposal method could improve scheelite recovery by 2% (approximately) and could reduce the daily operation costs of the plant by approximately 108.57 USD.

For the diagnosis of glaucoma, optical coherence tomography (OCT) is a noninvasive imaging technique for the assessment of retinal layers. To accurately segment intraretinal layers in an optic nerve head (ONH) region, we proposed an automatic method for the segmentation of three intraretinal layers in eye OCT scans centered on ONH. The internal limiting membrane, inner segment and outer segment, Bruch’s membrane surfaces under vascular shadows, and interaction of multiple high-reflectivity regions in the OCT image can be accurately segmented through this method. Then, we constructed a novel spatial-gradient continuity constraint, termed spatial-gradient continuity constraint, for the correction of discontinuity between adjacent image segmentation results. In our experiment, we randomly selected 20 B-scans, each annotated three retinal layers by experts. Signed distance errors of −0.80 μm obtained through this method are lower than those obtained through the state-of-art method (−1.43 μm). Meanwhile, the segmentation results can be used as bases for the diagnosis of glaucoma.

In order to improve structure performance of the dish solar concentrator, a three-dimensional model of dish solar concentrator was established based on the high-precision numerical algorithms. And a virtual wind tunnel experiment with constant wind is adopted to investigate the pressure distribution of the reflective surface, velocity distribution of the fluid domain for the dish solar concentrator in different poses and wind speeds distribution. Some results about wind pressure distribution before and after dish solar concentrator surface and wind load velocity distribution in the entire fluid domain had been obtained. In particular, it is necessary to point out that the stiffness at the center of the dish solar concentrator should be relatively raised. The results can provide a theoretical basis for the improvement of solar concentrator dish structure as well as the failure analysis of dish solar concentrator in engineering practice.

The fatigue load spectrum and operation life evaluation of key components in the catenary system under the high speed train running condition were investigated. Firstly, based on the catenary model and pantograph model, the couple dynamic equations of pantograph—catenary were built with the Lagrange’s method; then the dynamic contact force was obtained by the Newmark method at the train speeds of 250, 280 and 300 km/h, respectively. Secondly, the finite element model (FEM) of one anchor section’s catenary was built to analyze its transient response under the contact force as train running; then the loading time history of messenger wire base, steady arm, registration tube, oblique cantilever, and straight cantilever were extracted. Finally, the key components’ fatigue spectrum was carried out by the rain-flow counting method, and operation life was estimated in consideration of such coefficients, such as stress concentration, shape and dimension, surface treatment. The results show that the fatigue life of the catenary system reduces with the increasing of train speed; specifically, the evaluated fatigue life of the steady arm is shorter than other components.

Many scientific and engineering problems need to use numerical methods and algorithms to obtain computational simulation results because analytical solutions are seldom available for them. The chemical dissolution-front instability problem in fluid-saturated porous rocks is no exception. Since this kind of instability problem has both the conventional (i.e. trivial) and the unconventional (i.e. nontrivial) solutions, it is necessary to examine the effects of different numerical algorithms, which are used to solve chemical dissolution-front instability problems in fluid-saturated porous rocks. Toward this goal, two different numerical algorithms associated with the commonly-used finite element method are considered in this paper. In the first numerical algorithm, the porosity, pore-fluid pressure and acid/solute concentration are selected as basic variables, while in the second numerical algorithm, the porosity, velocity of pore-fluid flow and acid/solute concentration are selected as basic variables. The particular attention is paid to the effects of these two numerical algorithms on the computational simulation results of unstable chemical dissolution-front propagation in fluid-saturated porous rocks. The related computational simulation results have demonstrated that: 1) the first numerical algorithm associated with the porosity-pressure-concentration approach can realistically simulate the evolution processes of unstable chemical dissolution-front propagation in chemical dissolution systems. 2) The second numerical algorithm associated with the porosity-velocity-concentration approach fails to simulate the evolution processes of unstable chemical dissolution-front propagation. 3) The extra differential operation is the main source to result in the failure of the second numerical algorithm.

The interaction of surrounding rock with a support system in deep underground tunnels has attracted extensive interest from researchers. However, the effect of high axial stress on tunnel stability has not been fully considered. In this study, compression tests with and without confining pressure were conducted on solid specimens and hollow cylinder specimens filled with aluminium, lead, and polymethyl methacrylate (PMMA) to investigate the strength, deformation and failure characteristics of circular roadways subjected to high axial stress. The influence of the three-dimensional stress on the surrounding rock supported with different stiffness was studied. The results indicate that the strength and peak strain of hollow cylinders filled with PMMA are higher than those of hollow cylinders filled with aluminium or lead, indicating that flexible retaining is beneficial for roadway stability. The results obtained in this paper can contribute to better understanding the support failure of a buried roadway subjected to high axial stress and thus to analyzing and evaluating roadway stability.

Deformation behavior and hydraulic properties of rock are the two main factors that influence safety of excavation and use of rock engineering due to in situ stress release. The primary objective of this study is to explore deformation characteristics and permeability properties and provide some parameters to character the rock under unloading conditions. A series of triaxial tests with permeability and acoustic emission signal measurement were conducted under the path of confining pressure unloading prior to the peak stress. Deformation behavior and permeability evolution in the whole stress—strain process based on these experimental results were analyzed in detail. Results demonstrate that, under the confining pressure unloading conditions, a good correspondence relationship among the stress—axial strain curve, permeability—axial strain curve and acoustic emission activity pattern was obtained. After the confining pressure was unloaded, the radial strain grew much faster than the axial strain, which induced the volumetric strain growing rapidly. All failures under confining pressure unloading conditions featured brittle shear failure with a single macro shear rupture surface. With the decrease in deformation modulus during the confining pressure unloading process, the damage variable gradually increases, indicating that confining pressure unloading was a process of damage accumulation and strength degradation. From the entire loading and unloading process, there was a certain positive correlation between the permeability and volumetric strain.

The violation of monotonicity on reliability measures (RMs) usually makes the mathematical programming algorithms less efficient in solving the reliability-based user equilibrium (RUE) problem. The swapping algorithms provide a simple and convenient alternative to search traffic equilibrium since they are derivative-free and require weaker monotonicity. However, the existing swapping algorithms are usually based on linear swapping processes which cannot naturally avoid overswapping, and the step-size parameter update methods do not take the swapping feature into account. In this paper, we suggest a self-regulating pairwise swapping algorithm (SRPSA) to search RUE. SRPSA comprises an RM-based pairwise swapping process (RMPSP), a parameter self-diminishing operator and a termination criterion. SRPSA does not need to check the feasibility of either solutions or step-size parameter. It is suggested from the numerical analyses that SRPSA is effective and can swap to the quasi-RUE very fast. Therefore, SRPSA offers a good approach to generate initial points for those superior local search algorithms.

Identifying bottlenecks and analyzing their characteristics are important tasks to city traffic management authorities. Although the speed difference was proposed for the bottleneck identification in the existing research, the use of a secondary indicator has not been fully discussed. This paper strived to develop a method to identify the bottleneck on expressways by using the massive floating car data (FCD) in Beijing. First, the speed characteristics of bottlenecks on expressway were analyzed based on the speed contour map. The results indicated that there was a significant difference between speeds on the bottleneck and downstream links when a bottleneck was observed. The speed difference could indeed be used as the primary indicator to identify the bottleneck. However, it was also shown that a sufficiently large speed difference does not necessitate an activation of a bottleneck. The speed-at-capacity was then used as the secondary indicator to distinguish the real bottleneck from the non-bottleneck speed difference. Second, a practical method for identifying the bottleneck on expressways was developed based on the speed difference and the speed-at-capacity. Finally, the method was applied to identifying the bottlenecks of the 3rd Outer Ring Expressway in Beijing. The duration, affected distance, delay and cause were used to evaluate and analyze the bottlenecks.