Investigation of dispersed particle rotation characteristics in multi-phase flow is important in understanding the mechanism of multi-phase flow.In previous studies, many people focused on Magnus force produced by particle rotation in solid-gas two-phase flow, and proposed Magnus lift coefficient at different Reynolds numbers through experimental and theoretical investigations.In recent years, many researchers have studied the effect of particle rotation on the flow field through theoretical numerical simulation and dealt with particle rotation by improving multi-phase flow numerical model, and the simulated results are in agreement with experimental results.But because of the limitation of the model, it is impossible to take into full account the influence of particle rotation on particle cluster and surrounding flow field.From the experimental aspect, many researchers use high-speed digital imaging system to measure particle rotation speed and particularly one author successfully measured particle rotation speed in real gas-solid two-phase flow.Nevertheless, more accurate and efficient method needs to be developed.The authors of this paper proposed that the application of the direct numerical simulation in particle rotation characteristics simulation should be the emphasis of research in the future.And the technology of the reconstruction of 3D motion and structure of the object from image sequence in computer vision science should also be paid much attention in particle rotation speed measurement.

Synthetic biology is a new field under the guidance of engineering, which aims to redesign and rebuild natural biological systems, and meanwhile, design and synthesize new biological part, module and system.The advent of synthetic biology represents the tendency of natural science.Some marked achievements have been made in the areas of medicine and energy via synthetic biology methods.On one hand, novel synthesizing pathways have been successfully constructed in engineered cells to produce amorphadiene and taxadiene, which are precursors of antimalarial drug artemisinin and anticarcinogen taxol respectively.On the other hand, the constructions of fatty acid ester, fatty alcohol and higher alcohols synthesizing pathways have also been realized.In addition, several related synthetic bio-techniques accelerate reconstruction and evolution of engineered cells, which would offer convenient tools to construct novel functional cells for the purpose of bio-based manufacture.

3,6-Dichloropicolinic acid(3,6-DCP)as a highly active and low-toxicity compound is mainly used as herbicide, pesticide and plant growth regulator.Synthesis methods of 3,6-DCP are summarized as follows:(1)Due to high cost,hydrolysis of 3,6-dichloro-2-(trichloromethyl)pyridine or 2-cyano-3,6-dichloropyridine to prepare 3,6-DCP(in spite of the method is good in reaction selectivity)is not suitable for commercial production.(2)The synthesis method of 3,6-DCP by hydrolysis-reduction dechlorination of 2-cyano-3,4,5,6-tetrachloropyridine or reduction dechlorination of 3,4,5,6-tetrachloropicolinic acid is replaced by electrochemical methods because hydrazine and cyanide must be used in this method, though the method could provide many advantages, such as low price of raw materials and reaction equipment, high yield(70%—80%).(3)Electrochemical synthesis is gradually becoming the main method to prepare 3,6-DCP in commercial production, and very high yield(>90%)and product purity(95%)can achieved by using this method.In addition, two separation methods of 3,6-DCP are compared: extraction-stripping and neutralization-crystallization-extraction, the former is a more effective method for separation because of its better performance.Based on the statements above, some suggestions for the synthesis of 3,6-DCP are presented.

As an unconventional oil resource, oil sands and its processing technology has attracted much attention in China in recent years.Water-based extraction processes are the most important method to recover bitumen from oil sands.Two key steps are involved in this process:bitumen liberation from the sand grains and bitumen aeration followed by flotation to form a bitumen-rich froth.Any factor that causes poor liberation or poor aeration will result in a poor bitumen recovery.With the use of the advanced analytical instrumentations, such as the atomic force microscope(AFM),the understanding for the bitumen extraction from oil sands is extended from the macroscopic scale to the molecular level.It is found that the wettability of solids and water chemistry play significant roles in the processability of oil sands. Mechanisms related to the bitumen extraction processes are discussed in detail.The procedures of recovering bitumen from oil sands in industry are also briefly described.

Direct methanol fuel cells(DMFCs)are one of the most promising candidates for the next generation power sources in miniature electronic devices due to their high energy density, convenient storage of fuel, simple structure.DMFCs use methanol as fuel at anode and oxygen or air as oxidant at cathode, and these reactants are consumed at porous electrode by electrochemical reactions which lead to their concentration fluctuation and cell performance variation.So, adequate detection of the reactant concentration is necessary for operating DMFC systems, because they have important influence on the performance, efficiency and fuel utilization.In this paper the methods for measurement of reactants concentration in the DMFC are reviewed, and can be generally classified into physical and chemical two groups.Comments and analysis are given on their basic principles and application range as well as their merits and demerits.

A novel approach, laser induced fluorescence(LIF)technique, is proposed to visualize gas-liquid mass transfer and reaction in this work.The principle is to quantitatively capture the change of fluorescence signal intensity in liquid phase emitted by a fluorescence dye(e.g., Rhodamine B), where the concentration of the dye varies with time and space due to a coupled reaction by ozone in gas phase.The reaction process inside the liquid phase(droplet in this work)can be recorded, integrating the process of gas-liquid mass transfer and liquid-phase reaction.The experiment illustrated various micromixing behavior characterized by the concentration field inside the droplet under different environmental conditions, such as uniform gas flow with little disturbance and non-uniform gas flow with certain disturbance on the droplet, and the growing process of droplet.The straightforward visualization measurements improved the understanding on the mechanisms of gas-liquid mass transfer and micromixing inside a droplet.

A two-dimensional pseudo single phase model is proposed to describe the flow and mass transfer phenomenon on a four-pass distillation tray with a diameter of 12.6 m by combination of computational fluid dynamics(CFD)and computational mass transfer(CMT)equations.The resistance and bubbling effect of the uprising gas phase are considered.The velocity profile and concentration distribution are calculated for the tray designed by traditional equal bubbling area method and for the modified tray under different operational conditions.For the traditional four-pass distillation tray, the liquid loading ratio(Q₁/Q₂)of 1.0 is first considered.Simulated results show that on its left-side tray there exists a recirculation region, which is in accord with the observations from industrial practice, and a large velocity difference between the arc-shaped region and the main flow region.These two factors account for the lower separation efficiency on the left-side tray compared with that on the right-side tray.Then the influence of Q₁/Q₂ on tray efficiency is investigated.Simulated results give an optimal Q₁/Q₂ around 0.8 in terms of tray efficiency.In order to optimize the tray configuration and improve the tray separation efficiency, a modified tray configuration is constructed by introducing several deflectors.The simulation is conducted under the same operational conditions as those for the traditional tray.Calculated results present much more uniform flow regime with the disappearance of recirculation phenomenon and the Murphree tray efficiency is increased by 4.53%—9.22%（Q₁/Q₂=［0.5,1.5］） compared with the traditional tray.With these deflectors, the optimal Q₁/Q₂ in terms of tray efficiency changes from 0.8 to 0.7, probably due to the much more uniform flow pattern at low Q₁/Q₂ as a result of deflectors.

The liquid dehumidifiers are the key unit for liquid desiccant cooling system(LDCS)and the internal heat and mass transfer of dehumidifier have important influence on the performance of LDCS.Based on the adiabatic dehumidification model, a new model considering non-thermal equilibrium was put forward to evaluate heat and mass transfer coefficients.By simulation calculation, it is found that the outlet parameters of air and liquid from non-thermal equilibrium model agree well with the experimental values, so that the model is better to evaluate heat and mass transfer coefficients.When the heat capacity rate ratio C^*≥1.0, the calculation results for the number of mass transfer units and Lewis factor from non-thermal equilibrium model are much better than those from the adiabatic model, while the two models give almost the same results when C^*≤0.05.

The liquid dehumidifiers and regenerators are the key units for liquid desiccant cooling system(LDCS)and the ducts of liquid and air in the equipment are generally very complicated.Consequently, it is not easy to evaluate the internal heat and mass transfer of dehumidifier and regenerator.In this study, a simple falling film dehumidifier/regenerator was constructed and the dehumidification and regeneration experiments with countercurrent flow of liquid were carried out.The new Le-h_D measurement method considering non-thermal equilibrium obtained previously was used to evaluate the coupled heat and mass transfer coefficients of plate falling film experiments under various experimental conditions.All these heat and mass transfer coefficients were rearranged in criterion equations to predict the performance of more intricate liquid dehumidifier/regenerator.

If there are foreign nuclei(solid particles or liquid droplets etc.)existing in natural gas flow, condensation of hexane would take place on the foreign nuclei, and thus both homogeneous and heterogeneous condensation would occur in the throttling process.A uniform mathematical model for homogeneous and heterogeneous condensing flow was built to study flow field characteristics and condensation properties of hexane in the throttle valve.The effects of initial particles radius, concentration of the nuclei, back pressure ratio and total temperature on condensation properties of hexane were analyzed. It was shown that differential pressure and velocity of natural gas were very high in the throttle valve, and condensation was completed in a very short time.Owing to the high free energy barrier, homogeneous condensation of hexane could not occur until very high supersaturation ratio was reached. Homogeneous condensation would be restrained if both condensations coexisted in the condensing flow, which would cause the decrease of homogeneous condensation mass fraction.And the suppression effect became obvious when initial radius and concentration of the nuclei increased, under this circumstance the proportion of homogeneous condensation reduced compared to the case that only homogeneous condensation occurred.As back pressure ratio and total temperature increased, supersaturation ratio reduced which would cause the decrease of total condensation mass and proportion of homogeneous condensation simultaneously.

Based on one dimensional hydrodynamics and reaction controlled un-reacted shrinking core model, a mathematical model was developed to predict the reduction behavior of iron ore fines in a circulating fluidized bed(CFB)reactor.The size distribution characteristics of the ore fines were considered in the model, and both gas phase and solid phase conversions were involved.The calculated results were in good agreement with the experimental data reported in the reference.The influence of gas velocity, gas composition, and circulation ratio on the reduction performance was investigated in an industrial scale CFB reactor.The results showed that solid phase conversion rate increased to different degrees with the increase of gas velocity and decrease of degree of oxidation of reducing gas.But increasing gas velocity could decrease gas phase conversion rate while decreasing degree of oxidation could increase gas phase conversion rate.The degrees of reduction for particles of different sizes became more even with a proper circulation ratio.

Field synergy principle is based on the steady state laminar thermal boundary layer integral equations and has been validated by the experimental data and numerical simulations.However, at present, the descriptions for the general relation between the field synergy angles in different scopes and the nature of additional equivalent source and the mechanism for the two effects to enhance or weaken the heat transfer processes are lacking, which are essential for control of the field synergy heat transfer process.In this study, a universal theory for the field synergy principle is obtained through the analysis and establishing an equation for the total heat flux density vector divergence.The results show that the field synergy changes the divergence.Since the divergence reflects the relation between the source in the region and the flow on the border, the analysis of the effect of field synergy angle change on the divergence may identify the nature of additional equivalent source, as well as the change of volume and direction of the total heat flux density vector, so that the mechanism for heat transfer process to be enhanced or weaken is revealed.

Thermomagnetic convection of air in a cubic enclosure with an electric coil inclined around the X axis was numerically investigated under nongravity and gravity environment.The cubic enclosure was heated isothermally from left-hand side vertical wall and cooled isothermally from the opposite wall while the other four walls were thermally insulated.Biot-Savart’s law was used to calculate magnetic field.The governing equations in primitive variables were discretized by the finite-volume method and solved by the SIMPLE algorithm.Computations were performed in a range of the inclination angle of coil x_euler from -90° to 90°, and magnetic force parameter γ from 0 to 200.The flow and temperature fields for the air thermomagnetic convection were presented and mean Nusselt numbers on the walls were calculated and compared.The results show that both the magnetic force and the coil inclination have significant effect on the flow field and heat transfer in a cubic enclosure.The overall heat transfer is enhanced gradually with the increase of γ.Under the zero gravity environment, the resulted convection is symmetrical in terms of the angle at x_euler=45° when the range of inclination angle is from 0° to 90°.The coil inclination changes the average Nusselt number and a local maximum is obtained at x_euler=45° for every case.Local minima are obtained at x_euler=0°, 90°, etc. Values of the average Nusselt number appear periodically with period 90° in the inclination angle.Under the gravity environment, the resulted convection is symmetrical in terms of the angle at x_euler=0°, 90° when the range of inclination angle is from -90° to 90°.Values of Nu_m appear periodically with period 180° in the inclination angle.The coil inclination changes Nu_m and a local maximum is obtained at x_euler=45° for every case.

Five modular air-cooled chilled(hot)water units with 60 kW of refrigerating output were used to carry out experiments.With leaving water temperature at 5—12℃, dry-bulb temperature at 25—42℃, and the relative humidity of 40%, the chilling and heating performance of modular air-cooled chilled(hot)water units with electronic expansion valve and modular energy regulation system was studied at changing ambient temperature.A series of experimental data about refrigerating capacity, power consumed by refrigeration, refrigerating COP, heating capacity, power consumed by heating and heating COP were obtained, and the influence of ambient temperature on the performance was evaluated.The comparison shows that the air-cooled chilled(hot)water units with electronic expansion valve and modular energy regulation system present better energy regulation performance and energy saving performance than the air-cooled heat pump units with thermal expansion valve, especially when the working condition deviates more from the designed working condition.For example, the refrigerating COP of the former is 1.50 times that of the latter and the heating COP is 1.61 times that of the latter at the ambient temperature of 40℃ and leaving water temperature of 7℃, and at the ambient temperature of 0℃ and leaving water temperature of 45℃.

Serrated spiral-finned-tube, developed from solid spiral-finned-tube, has been widely applied in large-scale heat-exchange facility due to its advantages such as easier manufacture, more extended heat transfer surfaces, higher heat transfer coefficient and fin efficiency.For the effects of fin pitch on heat transfer and flow resistance of serrated spiral-finned-tube banks(SSBs), nine SSBs with staggered layouts in terms of various fin pitch were tested based on the analysis on its influencing mechanism.The experimental results are as follows.At the same fin-side Re,Nu increases 19% and Eu decreases 8% with the fin pitch increased from 3.831mm to 4.167mm.The effect of fin pitch on fin-side Nu becomes little when the fin pitch is larger than 4 mm since the gas penetrates the fin-gap more easily and fully flushes the fin-surface.The comprehensive heat transfer performance index j/f (ratio of Colburn heat transfer factor and friction factor)of fin-side first increases and then decreases as Re increases, with higher j/f in Re=7000—10000.At the same fin-side Re, the index j/f is higher as the fin pitch is larger, increased about 28% with the fin pitch increased from 3.831 mm to 4.167 mm.The experimental results were compared with the correlations in literature.The correlations for Nu and Eu on SSBs with staggered layouts, which take fin pitch, transverse pitch and longitudinal pitch of tube banks into accounts, were presented for engineering applications.

The representative interactive flamelets(RIF)model was coupled with the large eddy simulation(LES)method to predict the turbulent combustion in a diesel engine.The new approach is specifically suitable for the simulation of the complicated combustion processes in internal combustion engines because the multi-scale and highly-transient turbulent motion can be well reproduced，and detailed chemical mechanism can be used.By combining the KIVALES-RIF code developed in previous work with a reduced n-heptane oxidation mechanism，the combustion processes and emission characteristics of a single-cylinder version of the Caterpillar 3400 series heavy-duty diesel engine was simulated under the baseline operating condition.The results indicated that the predicted ignition delay，in-cylinder pressure，heat release rate and pollutants emission levels were in good agreements with the experimental results.Comparison between the predictions of the Reynolds averaged Navier-Stokes(RANS)method and the LES method showed that the turbulence model played an extremely important role in the prediction of the combustion processes.

This work was devoted to investigating the pneumatic classification behavior of coal particles(0—10 mm)in a bottom-fluidized transport column.The tested influence parameters included superficial gas velocity of transport column, dimensionless velocity of particles, coal feeding position and rate, and internal baffle in the fluidized bottom.The classification performance was analyzed by measuring the amounts and size distributions of the elutriated particles, overflowed particles from the fluidized bed and the particles remaining in the bottom of the column.The Newton classification efficiency was used to quantitatively evaluate the classification performance.The results showed that there was an optimal dimensionless velocity for separating the fraction of particles below a given size via entrainment.With the increase of the targeted size, the Newton classification efficiency increased but the corresponding optimal dimensionless velocity gradually decreased.Feeding coal from a higher position and at lower rates facilitated the classification for small-size particles(via elutriation).The elutriated particle amount and the classification efficiency for a fraction below a given size both decreased when inserting a vertical baffle in the fluidized particles at the column bottom.

The spreading of a drop of an insoluble surfactant solution over precursor, which was driven by surfactant concentration gradient and temperature gradient caused by surface non-uniform heating was modeled.The dimensionless evolution equations of the spreading process, including the equation of film thickness and surfactant concentration, were derived on the basis of lubrication theory and calculated by PDECOL program.The effects of temperature gradient and concentration gradient on the spreading process were discussed.The results showed that decreasing Marangoni number, air-liquid interface Biot number and heating number, and increasing surface Peclet number could delay the spreading process.Changing surface Peclet number would lead to the most remarkable difference in surfactant concentration distribution.

The potential of calcium peroxide(CaO₂)as a source of hydrogen peroxide(H₂O₂)in Fenton oxidation has been gradually taken note.In order to understand the characteristics of CaO₂-based Fenton reactions, experiments were conducted using methylene blue spectrophotometric method to investigate effect of catalyst type, initial pH, CaO₂ dose,molar ratio of catalyst to CaO₂ (n_Fe/n_CaO2), and phosphate buffer concentration on production of hydroxyl radicals(HO·).The results showed that under the experimental conditions Fe²⁺ had better catalytic ability than Fe³⁺ and Cu²⁺.The optimal Fenton reaction conditions were:Fe²⁺ as catalyst,initial buffer pH=4,CaO₂ dose 1 mmol·L^-1,n_Fe/n_CaO2=1/5,phosphate buffer concentration 40 mmol·L^-1.It was also indicated that the release of H₂O₂ and Fenton reaction were regulated by the dissolution process of CaO₂ that could be a potential substitute for H₂O₂ in in-situ Fenton oxidations, because of decrease of H₂O₂ loss as well as negative impact of Fenton processes on the environment.

Stability of bisphenol A(BPA)in high-temperature water(HTW)was studied in fused silica capillary reactor(FSCR, ID1.0 mm).It was found that the stability of BPA was influenced by both temperature and heating time obviously.At 260—360℃，4.7—18.7 MPa and heating time of 15 min, the recovery of BPA decreased from 87.8％ to 11.1％.At 260℃ and heating time of 15—75 min, the recovery of BPA decreased from 87.8％ to 43.5％.It was noted that the wall effects of the batch autoclave promoted the decomposition of BPA by comparing the experiment results of FSCR and batch autoclave.Additional kinetic analysis suggested that BPA in HTW followed a first-order reaction kinetics with activation energy of 76.1 kJ·mol^-1.Upon examination in water inside a FSCR(ID0.3 mm)under a microscope, phase changes were observed when BPA was heated.It started to melt at a low temperature, then dissolved completely in water above 219℃ and eventually became an aqueous fluid coexisting with vapor phases.

The short circuit flow at the bottom of the vortex finder is an important factor for evaluating the performance of cyclone separators，but it is difficult to determine the altitude range of the short circuit flow.General measuring method is not available and the calculation results are quite different with various computation methods.Thus，to design a new separator many experiments are usually needed，which is time consuming and always costs too much.Here a computation method of short circuit flow based on CFD software is proposed.With the inflection point of the centripetal and centrifugal flow on the cross-section of the position at the bottom of the vortex finder，appropriate range for computing short circuit flow can be determined.The shape of the range is approximately annular and the descending flow rate across this range may be regarded as the total short circuit flow value.The calculation process is easily completed through the simulation result and the computation for short circuit flow is reliable.This method can be applied to multi-inlet and single-inlet separators.

Ternary mixed solvents, composed of DMF(N,N-dimethylformamde), DMSO(dimethylsulfoxide)and NMP(N-methylpyrrolidone)for separation of benzene and cyclohexane by extractive distillation, were examined in a vapor-liquid equilibrium experimental apparatus.The relative volatilities of benzene and cyclohexane were investigated.It was found that the ternary mixed solvents presented better “mixed solvent effect”, and were superior to the single solvent.The relative volatilities of benzene and cyclohexane at different molar mixed solvent ratios were determined, and the optimal molar ratio of the ternary mixed solvents was obtained.The modified MDNUIFAC model was used to correlate the experimental data, and the vapor-liquid equilibrium of benzene-cyclohexane-solvents system can be described well by the modified MDUNIFAC model.

The constraints of output variables, input variables and intermediate variables exist generally in chemical process control.The inconsistency in different constraints cannot make all of constraints satisfied, and optimal controller does not have feasible solutions, which adversely affects production.Based on convex polyhedron geometry, the feasibility analysis of constrained optimal control in chemical processes was transformed into whether two convex polyhedra intersect or not, and the reasonable constraints adjustment was transformed into a series of linear programming or nonlinear programming when the constrained optimization problem was infeasible.An algorithm for feasibility analysis and automatic constraints adjustment of constrained optimal control independent of user intervention was proposed. Simulation results of typical control problem of a heavy oil fractionator proposed by Royal Dutch/Shell Group showed that when the constrained optimization problem was infeasible the proposed algorithm could make constraints adjustment automatically and effectively, with small overshoot, smooth change of control action, and a certain control overdesign.

To handle the nonlinear problem for process monitoring, a new technique based on kernel partial least squares(KPLS)is developed.KPLS is an improved partial least squares(PLS)method, and its main idea is to first map the input space into a high-dimensional feature space via a nonlinear kernel function and then to use the standard PLS in that feature space.Compared to linear PLS, KPLS can make full use of the sample space information, and effectively capture the nonlinear relationship between input variables and output variables.Different from other nonlinear PLS, KPLS requires only linear algebra and does not involve any nonlinear optimization.For process data, firstly KPLS was used to derive regression model and got the score vectors, and then two statistics, T² and SPE, and corresponding control limits were calculated.A case study of the Tennessee-Eastman(TE)process illustrated that the proposed approach showed superior process monitoring performance compared to linear PLS.

Injection molding is the most widely used process for producing plastic products.In general, injection processing can be divided into three stages: filling, packing and cooling，in which warpage defect is one of the most important quality problems.Since the quality of the injection-molded parts are mostly influenced by process conditions, how to determine the optimum process conditions to reduce warpage becomes the key to improving the quality of parts.In this study, the mold temperature, melt temperature, injection time, packing time, packing pressure and cooling time were regarded as process parameters(design variables).Moldflow Plastic Insight software was used to analyze the warpage of the injection molding parts.BP neural network model was used to construct an approximate function relationship between warpage and the process parameters, replacing the expensive simulation analysis in the optimization iterations.The adaptive process was performed by improved Expected Improvement(EI)which was a weighted infill sample criterion.This criterion could balance local and global search and tend to find the global optimal design.Numerical results showed that the proposed adaptive optimization method could effectively reduce the warpage of the injection molding parts.

Case revision, as a crucial and difficult step in case-based reasoning technology, exists defects on the hard acquisition of revision knowledge and poor generality for modifying method.Aiming at these problems, in the paper, the extension theory is combined.On the basis of unified and deep case description and similarity retrieve by the basic-element models, the satisfaction evaluation is made for the similar cases.Then, for the evaluated incompatible similar cases, a case-replacement extension repair approach is proposed based on the character difference.Finally, an assessment is applied to determine the best solution from the modified cases.Therefore, a complete case extension revision strategy is formed.The determination of the number for the theoretical plate in the distillation columns is taken as an example for the verification of the proposed strategy.The application result indicates that the strategy has a lower dependence on knowledge and stronger learning ability, which provides a new idea for the further study on the case revision technology.

As a key factor in model-based control technique, model fidelity has significant influence on control performance.Model-plant mismatch(MPM)is an important step in the procedure of control performance monitoring and system maintenance.A subspace-based MPM approach for control systems was proposed.First, the residual was constructed through subspace transformation.Then the residual was analyzed by using statistical local approach, from which an indicator could be constructed to detect the mismatch.Using orthogonal subspace, it was not needed to estimate system states and residual could be obtained only by using input and output data.Furthermore, based on the state space model, the proposed approach was suitable for MIMO process.The effectiveness of the proposed approach was illustrated by both simulation and industrial applications.

Corrosion products on iron ware from “Huaguang Reef Ⅰ” and the removal of harmful salts were investigated.The surface resistivity of the rust on one iron ware named HTQ6^# was （3×10³）—（1×10⁸） Ω, and the rust was completely mineralized.The rust including Fe₃O₄, α-FeOOH, γ-FeOOH and FeOCl was magnetic.In order to avoid the damage of the harmful rust including γ-FeOOH and FeOCl on the original appearance of the cultural relics, desalination process using constant current density of -0.5 mA·cm^-2 in 2.5% NaOH solution was studied.The results were shown as follows.The proportion of chloride ion removed was 53.31%, which was higher than that by using impulsive current, at the final time of desalination for 264 h.Meanwhile, the concentration of chloride ion in the solution was 6.1 mg·L^-1 and electrical efficiency was 1.95%.In this process, the amount of chloride ion in the iron matrix decreased from 2.03% to 0.95% at applied potential of -2.25—-1.61 V with the potential stabilized at -1.61 V.

The protein of silkworm pupae(PSP)is known for its nutritional value.The hydrolysates of PSP contained bioactive peptides with important bioactive activities, but enzymatic hydrolysis kinetics of PSP was less reported.This study applied lumping kinetics to the PSP-alcalase system.Solid-state PSP was the main substrate and soluble PSP was hardly responsive to alcalase.The molecular weight distribution of hydrolysates of solid-state PSP was analyzed by high performance size-exclusion chromatography(HPSEC)and the principle of lumping kinetics was built based on solubility of PSP and molecular weight distribution of hydrolysates.The lumped components of the complex reaction system were defined and a three-lumping reaction network was proposed.Reaction of the lumps was described with intrinsic kinetic equations, which contained product inhibition, substrate inhibition, enzyme inactivation and the variation of different lumped components in different times, and the system of differential equations for this reaction of lumps were established.The rate constant of each lump reaction was estimated by the Marquardt method.The reliability of the model was verified by comparing the computed values with the experimental values, and the average regression error was less than 5%.

Succinic acid production by repeated batch fermentation based on high density culture was studied.The result showed that E.coli could convert glucose to succinic acid in aqueous solution of glucose and a neutralizer.When cell density increased approximately to 28 g·L^-1(DCW), the aerobically grown cells were directly brought into anaerobic conditions.Glucose concentration was maintained at about 10 g·L^-1 with constant flow feeding.Cells were recycled from final fermentation broth for the next batch of repeated fermentation when the last fermentation was stopped at 30 h .After two-stage fermentation and two cycles of cell reincubation, the concentration of succinic acid was 95.1 g·L^-1, 79.7 g·L^-1 and 64.4 g·L^-1 respectively.The average succinic acid yield and productivity were 72.5% and 1.93 g·L^-1·h^-1 respectively, with an increase of 29.5% and 25.9%,compared with those in the two-stage fermentation .

As a cost-efficient enhanced technique, air sparging is used to address subsurface contamination worldwide.It involves the injection of contaminant-free air into the saturated aquifer in an attempt to enhance aerobic biodegradation and induce mass transfer of volatile contaminants into vapor phase.The zone of influence(ZOI)of air sparging(AS)is a critical parameter for the mechanism studies and project designs, which varies with site characterizations.A case study in northeast China featured by a typical interlayer groundwater system contaminated by hydrocarbons was conducted.Air sparging with soil vapor extraction for remediation was performed based on site characterizations.Groundwater level, temperature and dissolved oxygen in groundwater were monitored in field scale during the air sparging running.The spatial and temporal responses of air sparging to the above parameters were analyzed to reflect the environmental effects of remediation activities, and indicate the ZOI.Mathematical methods, including the least square method and double integral were used to determine the theoretical boundary and volume of the ZOI.In addition, a mathematic model was set up to quantify the water inter-flow in the ZOI on the basis of the understanding of groundwater displacement by sparged air.The results showed that the radius of influence in this case was up to 9 m, and the ZOI presented an inverted cone with 362.04 m³ groundwater in it before AS.Groundwater was up-lifted to the top of the aquifer and then overflowed to the surrounding area, while the flux rate descended with time and the cumulative flux reached 0.97 m³ in 6 h.It could be safely concluded that the lateral groundwater movement was not significant in this case.The knowledge from the comprehensive study could provide useful insight into the design efficiency of in situ air sparging and assist in developing and controlling the sparging system, and even tell the fate and transport of the water-air interaction.

In order to study the effects of anoxic condition on release of phosphorus in an enhanced system for phosphorus removal with granular sludge, batch tests were carried out using acetate and propionate(carbon molar ratio=2∶1)as carbon source and adding different amount of NO^-₃-N(0, 20, 30, 50 and 75 mg·L^-1, pH=8.0)and NO^-₂-N(10, 20, 40 and 60 mg·L^-1, pH=7.0, 7.5 and 8.0)in initial anaerobic stage.The results showed that addition of NO^-₃-N and NO^-₂-N had no obvious inhibition on release of phosphorus.Absorption of fatty acids(VFAs), phosphorus release and denitrification took place simultaneously,and absorption rate increased while release rate of phosphorus decreased because of competition between denitrifying bacteria and phosphorus accumulating microbial granule(PAOs)for carbon source.The results of batch tests at various NO^-₂-N concentration and at different pH showed that FNA, rather nitrite, had a strong stimulation effect on P-release and the rate of P-release increased by 4 times when FNA concentration was higher than 0.004 mg HNO₂-N·L^-1.Meanwhile, FNA had obvious suppression on absorption of VFA and synthesis of PHA, and the absorption rate and synthesis mass decreased by 53% and 70%, respectively.Based on analysis of energy generation and metabolism of PAOs as well as toxic action of nitrite, the mechanism stimulating P-release of FNA was, in presence of free nitrous acid, that PAOs was required to release more energy to provide adequate proton motive force(pmf).

Denitrifying phosphorus removal was stably achieved with a biological step feed nutrient removal process from real municipal wastewater.The effects of operational parameters on the denitrifying phosphorus removal and the improvement of nutrient removal by intensifying anoxic phosphorus uptake as well as control strategies about maintenance of denitrifying phosphorus removal in the modified University of Cape Town（UCT）step feed process were discussed.The results indicated that denitrifying accumulating bacteria（DPAOs）could be successfully enriched with the maximum proportion and anoxic phosphorus uptake rate of 39.2% and 3.19—4.48 mg P·（g VSS）^-1·h^-1 respectively，according to the process shift from the A/O model to the modified UCT model.Both anoxic and aerobic phosphorus uptake rates and phosphorus removal efficiency increased with the increase of anaerobic volumes，and the optimum anaerobic/anoxic/oxic volume distribution was 34/102/204L（1/3/6）.When the sludge return ratio and internal recycle ratio were respectively set at 100% and 75%，

The A/A sequencing batch reactor(SBR)was used to enrich denitrifying and phosphorus accumulating bacteria(DPB).Denitrifying and phosphorus accumulating tests were performed by using acetic acid and glucose as substrate.The metabolic mechanism and change of phosphorus/nitrate/COD in water and polyhydroxyalkanoates(PHA)/glycogen in sludge were studied.The release of poly-phosphate would control the combination of PHA.At the anoxic stage breakdown of PHA was used as carbon source to denitrify nitrate, and the adenosine triphosphate(ATP)thus generated provided energy for accumulating phosphorus.So it is important to track the change of PHA, not COD when the denitrifying and phosphorus accumulating process was studied.When glucose was used as substrate, fermented bacteria broke down glucose into volatile organic acid of small molecules, then non-fermented bacteria could play a role fully.At the anaerobic stage, 85% energy came from the release of phosphorus, 15% energy came from the fermentation of glycogen.At the anoxic stage, 85% PHA breakdown was used to accumulate  phosphorus, 15% was converted into glycogen.The metabolic mechanism could be simplified.

In this work, the effects of total concentration of glucose-xylose mixture and mass ratio of xylose to glucose on hydrogen production, hydrogen production efficiency, bacteria growth and residual sugar content were investigated in the co-fermentation of glucose and xylose.It was shown that maximum hydrogen production efficiency of 2.1—2.2 mol H₂·mol^-1 was obtained from xylose at initial xylose concentration of 5—10 g·L^-1, which was twice of that from glucose under the same experimental conditions.And the maximum cumulative hydrogen yield of 3020 ml·L^-1 was obtained at initial xylose concentration of 15 g·L^-1，which was equal to that from glucose at initial glucose concentration of 30 g·L^-1.As initial sugar concentration was greater than 30 g·L^-1, cumulative hydrogen yield from xylose was found to decrease rapidly, while a slow increase was found from glucose with increasing sugar concentration.Under a mixed sugar environment with initial total sugar concentration of 15 g·L^-1, maximum cumulative hydrogen yield was obtained at the mass ratio of 1∶0.5(xylose to glucose), which was the best environment for bacteria growth.However, at initial total sugar concentration of 30 g·L^-1, the medium with a mass ratio of 1∶2(xylose to glucose)was the best environment for bacteria growth.In this case, an optimum cumulative hydrogen yield of 4150 ml·L^-1 was obtained, which was 1.37 or 1.46 times of that from respective fermentation of glucose or xylose at initial concentration of 30 g·L^-1. In the co-fermentation process of glucose and xylose, both of glucose and xylose were consumed simultaneously in different degrees by anaerobic mixed microflora.It was interesting to note that xylose was easier consumed than glucose at the concentration less than 15 g·L^-1, while glucose was easier consumed than xylose at the concentration greater than 22.5 g·L^-1.The results would be helpful for the further study of hydrogen production from biomass.

Red mud is an alkaline solid waste released from Al₂O₃ smelting and can be used as capture agent to absorb CO₂ in fume.In this paper, red mud from Bayer process of China Aluminum Corporation was selected and used, and the effect of reaction temperature, time, and ratio of solid to liquid, agitation speed and CO₂ flow rate on absorbing efficiency of red mud was investigated to obtain the best process parameters and conditions.The results show that one gram fluidic red mud containing 44.12%（mass） water can capture 0.11—0.12 g CO₂ at 40℃, under the ratio of solid to liquid of 1∶10, the reaction time of 120 min, the agitation speed of 700 r·min^-1 and the CO₂ gas flow rate of 0.25 L·min^-1.The properties of red mud before and after absorbing CO₂ were characterized by XRD, SEM, BET, and FT-IR.The data from XRD show that main components of red mud are Ca₂SiO₄, CaCO₃,Na₂Si₂O₅, CaTiO₃, Ca₃Si₂O₅, Ca₃Al₂O₆, and NaCO₃, after the reaction with CO₂, the peaks of Ca₂SiO₄, Na₂Si₂O₅ and Na₂CO₃ in XRD pattern disappear.Furthermore, owing to the alkaline substances in red mud can react with CO₂ to get carbonates；some new phases can be found in the XRD spectrum.The analysis by SEM, BET and FT-IR imply that the microstructures and shapes of red mud have occurred a change and are different before and after capturing CO₂.These data results show that red mud can be used for capturing CO₂ in fume and provide an effective way with low cost for reducing carbon emissions.

Waste corrugated board was ground to paper pulp, which was used to prepare the foamed waste paper pulp/high density polyethylene（HDPE）composites by compression molding with HDPE.The Rosand  double-barrel capillary rheometer was used to study the influences of the blowing agent AC(azodicarbonamide)content，waste paper pulp content，temperature and different blowing agents on the melt of the composites.Scanning electron microscopy（SEM）was also used to observe the effects of different contents of AC and waste paper pulp on cell morphology.The results showed that the melt behavior of the foamed waste paper pulp/ HDPE composites was pseudoplastic flow, and when shear rate was up to 600 s^-1 wall slip was observed.The viscosity of the melt was significantly reduced with increasing content of AC,but increased with increasing content of waste paper pulp.When shear rate was reduced to 275 s^-1 or below, the viscosity of the melt was reduced as temperature increased；while when shear rate went up to 275 s^-1 or higher, the viscosity of the melt increased as temperature increased.When shear rate was reduced to 325 s^-1 or below, the melt with endothermic blowing agent(NaHCO₃）showed the highest viscosity；when shear rate went up to 325 s^-1 or higher, the melt with exothermic blowing agent AC showed the highest viscosity.The number of cell increased and the size of cell became smaller with increasing AC content,but the number of cell was reduced and the size of cell became larger with increasing content of waste paper pulp as observed by SEM.

A novel heat released microcapsule-type latent curing agent was prepared by solvent evaporation technique with 2-methylimidazole(2MMZ)as core material and polystyrene(PS)as wall material.The chemical structure, core material content, surface morphology, size distribution and curing characteristics of this microcapsule-type curing agent were characterized by FT-IR, TGA, SEM, granulometer and DSC.The obtained microcapsules had a smooth surface and displayed a narrow size distribution with the mean size about 10.18 μm, and its core material content was about 40.36%.In addition, the one-component adhesive made from the microcapsules and epoxy resin E-51 showed excellent curing characteristics and latent properties.It was found that the E-51/2MMZ-PS microcapsule system could be cured at 100℃ in 1 h and its shelf life at room temperature was more than 1 month.

A latex of anionic polyacrylamide dispersed in an aqueous solution was prepared through aqueous two-phase copolymerization of acrylamide(AM)/acrylic acid(AA)/methyl methacrylate(MMA)with the stabilizer poly(acrylic acid sodium)in ammonium sulfate solution and 2,2′-azobis［2-(2-imidazolin-2-yl)propane］-dihydrochloride as initiator.By using spectrophotometer, the phase separation point was determined online where the transparence of reaction solution declined suddenly.The effect of various parameters on the critical conversion and critical molecular weight at phase separation was measured by the bromating method and gel permeation chromatography respectively.The experimental results showed that the addition of MMA could introduce hydrophobicity to the polymer chain and increase the interfacial tension of the two phases, as a result it was easier for the polymer chain to precipitate, which in accordance made the critical conversion and critical molecular weight at phase separation decrease.The total concentration of AM and AA was also related to the relative amount of MMA segment in the polymer chain. As the total concentration of AM and AA increased, the relative amount of MMA chain segment decreased. Thus the critical conversion at phase separation decreased while the critical molecular weight at phase separation increased.AA introduced electrostatic repulsion to the polymer chain and as the mass feed ratio of AA to AM decreased, the polymer chain was easier to coalesce because of the decrease of electrostatic repulsion.Salt concentration and stabilizer concentration had similar effects on the critical conversion at phase separation, but different effects on the critical molecular weight at phase separation.In addition, the increase of temperature was unfavorable for phase separation.It enhanced the solubility of the polymer chain and accelerated the growth of the polymer chain.

The synthesis of high impact polystyrene(HIPS)with the usage of a tetrafunctional peroxide initiator was investigated.The polymerization performance of a commercial initiator polyether poly-t-butylperoxy carbonate(JWEB50)was compared with that of its monofunctional counterpart, tert-butyl(2-ethylhexyl)monoperoxycarbonate(TBEC).It was shown that the polymerization kinetic curves completely overlapped at the same polymerization temperature when the molar concentrations of ［O-O］ were equal for these two initiators.And the higher the molecular weights, the equal polymerization rate could be obtained simultaneously by tetrafuctional JWEB50 compared to monofuctional TBEC under the same other conditions.The effect of polymerization temperature on molecular weight of HIPS prepared with JWEB50 or TBEC was investigated.It suggested that the molecular weight changed slower with the increase of polymerization temperature for JWEB50, compared to TBEC.That meant the molecular weight-increasing effect of JWBE50 would be more pronounced at high polymerization temperatures.The effect of initiator type on graft efficiency was also studied.At the same molar concentration of initiator, it was found that the graft efficiency was dramatically improved with the usage of JWEB50.It was also shown that the graft efficiency increased with the increase of polymerization temperature, but decreased with the increase of conversion.And the evolutions of viscosity during the preparation of HIPS recorded on-line by rotation rheometer(HAAKE RS6000)were very similar for these two initiators when the molar concentrations of ［O-O］ were equal.The two viscosity versus time curves completely overlapped with each other.And the phase inversion turned out to be flat in the curves.The phase inversion flats for both initiators were found to occur at a monomer conversion range around 18%—25%.

The failure process of epoxy-coated rebars under different magnitudes of loads in simulated concrete pore solution with chloride ions was studied by electrochemical impedance spectrum(EIS)technology.The results showed that coating resistance of the sample under load declined, and water absorption increased obviously.The higher the load was, the faster the failure of the sample would be.The coating water absorption test result was consistent with that of EIS.In addition, the applied load made the coating adhesion of the sample decline, and the adhesion decreased more obviously under a higher load.Therefore, the increase of coating porosity and the decrease of coating adhesion under applied load were the main reasons leading to the degradation of coating protective performance.