Abstract:A socket-joint system with partial bend-bearing capacity is a typical semi-rigid joint system.The numerical model of the joint was established with solid element and contact element using finite element software ANSYS.The mechanical characters of socket joint system were studied in detail and the bending stiffness curves of socket joints were established.Then,Using nonlinear beam element with spring elements in its each end,Kiewitt8 (K8) single-layer reticulated domes with socket joints were analyzed through ANSYS considering several different parameters including bending stiffness,ratio of rise to span,and division number.The influences of the parameters on the critical load of the domes were obtained.

Abstract:In order to investigate the influence of substructures on the failure behavior of steel reticulated domes subjected to severe earthquake,this paper built a more accurate numerical model.Applied on the fullrange dynamic response analysis method,two typical failure modes of reticulated domes with substructures were illustrated according to the rigidity of substructures.A Failure criterion was proposed to estimate the ultimate load of the single layer reticulated dome.It is observed that reticulated domes with rigid and flexible substructures have higher ultimate load compared with those with medium rigidity of substructures.The ultimate load increases with the decrease of the rise-span ratio and roof load.

Abstract:To widen the span range available for single-layer cylindrical reticulated shells,parameter analyses based upon nonlinear complete-process analysis were carried out.More than 400 examples of single-layer cylindrical reticular shells with width of 20 meters and supported along the four edges were calculated by finite element method software ANSYS and self-developed pre-and post-processing programs.The buckling modes,critical loads,plastic development levels were collected to investigate the effect of length-width ratio,rise-span ratio,initial geometric imperfection,and unsymmetrical distribution of loads.The results show that single-layer cylindrical reticular shells supported along the edges are still characterized by bending action,and the central regions of shell structure are the most sensitive areas.When the length-width ratio becomes larger,it is necessary to add the stiffening ribs to enhance the rigidity of shells,and the spacing of which should be set to make the length-width ratio be 1.0.The cylindrical reticulated shells are concluded to be sensitive to initial geometric imperfection,when the initial imperfection value reaches 1 /300 of the width,the critical loads of reticulated shell will be reduced by 30%.And when the loads are unsymmetrical distributed with p/g=1.0,the critical loads will be 86%-94% of those under symmetrical loading distribution.

Abstract:In this paper,an alternative method is presented to decide the optimal sensor number based on sensitivity.According to different influence ranges of different damage parameters and the degree of damage in each element and damage index,the minimum number of sensors and their placement can be found by sensitivity and genetic algorithms.Computational simulation of a 19-DOF simply supported beam is implemented with this method to evaluate the minimum number of sensors of different damage parameters.Moreover,damage location can be detected under single-damage situation and the element with the most severe damage can be identified in multi-damage case by the proposed sensor placement.

Abstract:Experiments on local compression bearing capacity of 11 specimens were reinforced with the spiral indirect reinforcements with A cor /Al ranging from 0 to 1.316 and 12 specimens simulating prestressed concrete beams were anchored in the side face of boundary beam.The calculation method for local compression bearing capacity of concrete with A cor /Al < 1.35 was obtained.The contribution of indirect reinforcements to local compression bearing capacity in current code was multiplied by the reduction factor of strength of indirect reinforcements (λ).When A cor /Al < 1,the enhancement coefficient of local compression bearing capacity due to indirect reinforcements (β cor) equals to 1,and the net local compression area(Aln) in the indirect reinforcements contribution is replaced by the net concrete core area (A cor,n).λ relates to A b /Al and A cor /Al,and increases with the increase of the product of two ratios.It is presented that the side face of boundary beam can be taken as a part of local compression calculated bottom area according to current code,and the local compression bearing capacity can be calculated according to corresponding formulas,when the ratio of length of calculated bottom area outside the section of prestressed concrete beam to width of boundary beam is less than 2 and the width of boundary beam is larger than the shorter length of local compression area.

Abstract:To systematically research the wind-resistance of double-layer reticulated shell structures widely used in various large public buildings,the wind-induced response of a typical double-layer reticulated shell was analyzed in this paper.The results show that for this kind of rigid structure,the background response contributes much more significantly than resonant response.Based on this condition,an equivalent static wind loads representation method which differs from the current code was put forward.Then the efficiency of this method was demonstrated on the basis of a numerical example.

Abstract:In order to investigate the performance of shearwalls connected with domestic nails in light wood frame structures,lateral resistance tests were conducted on 14 shearwalls in 7 groups with different dimensions and structural arrangements.Using ABAQUS,FE models of shearwalls were developed to simulate the structural behaviour.Both the experimental and numerical results show that failure of nail connections is the primary cause leading to the failure of shearwalls.The load-carrying capacity and the stiffness of shearwalls are proportional to the width.The performance of shearwalls with an opening,in terms of load-carrying capacity and stiffness,is higher than that of shearwalls without an opening but with the width equaling to the sum of the wall segments from the two sides of the opening.Gypsum panels improve the performance of shearwalls significantly.The empirical equations to predict the lateral resistance and stiffness of shearwalls were derived based on the test and FE modelling.

Abstract:In order to overcome the instability of usual kinds of acrylamide (AM) water in oil emulsion and reduce the dose of oil,a novel grafting copolymerization with cationic backbone of Layerde Double Hydrotalcides (LDH3) which was first used within W/O polyhedral cell (PHC) has been further researched for kinds of AM water-soluble monomers.The use of LDH3 acted as a cationic backbone to produce the cationic,zwitterionic,amphiphilic graft copolymers easily.This article focused on the polymerization process.The percentage and the dimensions of W/O PHC were observed and three different lamellar micelles of LDH3 were characterized by transmission electron microscope (TEM).The structure of final copolymer was characterized by infrared (IR).The products can be used as flocculants and the sludge dewatering agent effectively.

Abstract:According to limitations of previous chlorine decay models,a new model named as variable rate coefficient model (VRC) was built to improve the accuracy and reliability of chlorine decay model.The VRC model includes 4 parameters (X0,κ0,kmin and α) and is based on the kinetic rate equations from concurrent bimolecular second-order reactions.In this study,6 data sets from different water sources were used.Three models including VRC model,the first-order model and a second-order reactive species model built by Boccelli et al.were calibrated and compared.Results show that compared with other two models,the simulated values of VRC model agree very well with the experimental data.The VRC model can accurately predict chlorine decay.In order to ensure the accuracy of VRC model,it is preferable to calibrate the VRC model using data sets with a chlorine concentration that is at least as high as or even higher than that used during normal operating conditions.Furthermore,the chlorine concentrations used as model input should be adjusted to minimize the differences between model predictions and the observed chlorine concentration.

Abstract:To enhance the enzyme production of white rot fungus grown in northeast forest area in China,an indigenous white rot fungi Pleurotus ostreatus was used to investigate its laccase production and the culture medium was optimized by using shake flask experiment,and also the results were compared with the TK medium that is used universally.The results showed that the best medium for Pleurotus ostreatus were corn meal as carbon source with the concentration of 8 g/L,and ammonium chloride as nitrogen source with the concentration of 0.88 g/L.Under the optimized medium conditions,the laccase activity and biomass of Pleurotus ostreatus reached to 149.45 U/L and 0.045 2 g (dry weight) /L,respectively.The optimized medium made white rot fungi Pleurotus ostreatus 3 times laccase activity compared with TK medium.The statistical software SPSS was applied to do the significant difference test on the factors impacted laccase production.The results showed that the type of carbon source played a vital role in laccase production by Pleurotus ostreatus.It concluded that the optimized medium could enhance the laccase production,and the selection for the appropriate type of carbon course was the key to the preparation of the medium.

Abstract:To produce high quality drinking water more effeciently,a submerged membrane adsorption bioreactor (MABR) was evaluated for enhanced removal of organic matter from contaminated raw water.The results showed that the MABR was able to decrease influent TOC,CODMn,DOC and UV254,as well as BDOC and AOC by 41.3%,59.4%,36.7%,53.5%,67.9% and 44.0%,respectively,when powdered activated carbon (PAC) was dosed in the reactor at 8 mg/L.In the MABR,physical separation by the membrane,biodegradation by microorganism and adsorption by PAC were identified to jointly contribute to the removal of dissolved organic matter,with the respective contribution of 11.1%,7.6% and 18.0% in terms of DOC removal.However,enhanced separation effect on dissolved organic matter in the mixed liquor was observed for the membrane in MABR,which was attributed to a dynamic sludge layer formed on the membrane surface based on microscopic analysis.Taking into account of the short hydraulic retention time (0.5 h),MABR technology may be both technically and economically promising for application in drinking water treatment.

Abstract:This paper investigated the effect of temperature and the size of original particles on the flocs regrowth capability and the particles removal by flocs breakage and re-growth.The process of formation,breakage,and re-growth of flocs was investigated with PDA 2000.It is found that there is a full re-growth of broken flocs when coagulating in charge neutrality,while coagulating in sweep coagulation,the break-up process of flocs displays distinct irreversibility.The lower temperature results in the higher re-growth capability of broken flocs,and the reversibility of broken flocs formed by small particles is lower than that formed by big particles.The residual turbidity after re-growth of broken flocs is significantly lower than that before flocs breakage,which was little influenced by temperature.The size of original particles has positive effect on the discrepancy of residual turbidity before and after breakage.The technology can be used for the surface water with big particles and low temperature.

Abstract:Conventional flocculation kinetics based on velocity gradient law has several theoretical and applicable drawbacks.In this study,force analysis on flocs in turbulent flows was carried out and the results suggest that the vortex within characteristic scale is crucial in flocculation process,and the inertia effect of micro vortex causes the collision and aggregation of flocs.According to analysis of influenced factors on kinetic mass transfer and morphology of flocs,it is verified that the density of flocs is proportional to shear strength,whereas the strength of flocs presents inverse proportional correlation to shear strength.Furthermore,a new flocculation control factor defined as F r0is proposed based on kinetic and fractal morphology analysis.It is the modification of conventional flocculation control theory and provides a reference for practical design.

Abstract:Experimental data and model prediction was combined to quantify the enhancing effiecency of O3 on the photocatalytic oxidation of phenol.Titanium dioxide was immobilized onto spherical activated carbon (AC) particles via the sol-gel coating method.The isotherms of original AC and photocatalysts (TiO2-AC) annealed at 500 ℃ for phenol were measured.The results showed a reversible adsorption of phenol onto both kinds of particles at 25 ℃,which agrees well with the Freundlich adsorption isotherm in the dilute solution.Five oxidation processes,namely O3,UV/O3,UV/O3 /AC,TiO2-AC/UV/O2 and TiO2-AC/UV/O3,for phenol degradation in fluidized bed were compared and the photocatalytic ozonation was found to give the highest phenol conversion because of the combined actions of homogenous ozonation in the liquid phase,heterogeneous ozonation on the surface of catalyst support,and heterogeneous photocatlytic oxidation on the TiO2 catalyst surface.The experimental data of UV/O3 /AC process were used to determine the heterogeneous photolytic ozonation reaction rate constant.Predictions of the proposed model were compared with experimental results for the photocatalytic ozonation of phenol in the fluidized bed.The global photocatalytic oxidation constant was found to be enhanced by 14.8 times in photocatlytic ozonation process with ozone as the scavenger compared with the photocatalytic oxidation process with oxygen as the scavenger.

Abstract:The genomic DNA of H2-producing bacterium Ethanoligenens harbinense YUAN-3 was isolated and partially digested by Sau 3A I.The fragments of 2.5-5.0 kb were selected and inserted into BamH I digested plasmid pUC 19.The genomic clone library of strain YUAN-3 was constructed with 9 × 103 recombinants,indicating the coverage of clone library tends to be the theoretical value based on a 4.6 Mb average chromosome size of Clostridium,closest to Ethanoligenens harbinense.200 colonies were picked stochastically for sequencing and aligned with the database.The results imply that most of the sequences are similar with the hypothetical protein of hydrogen-producing bacterium whose complete genomes are sequenced,among which 49 sequences have the similarity over 70%,including folylpolyglutamate synthetase,DNA topoisomerase,acetyltransferase and so on,and 7 open reading frames (ORFs) of functional proteins or genes can be obtained.

Abstract:To investigate the effects of bromide concentration and ozone dosage on the formation of brominated trihalomethane formation potential (THMFP-Br) and BrO3-in ozonation,the effects of ozone dosage and reaction time on the distribution of bromide species were studied.The results show that THMFP-Br can be removed by ozone in water with different bromide concentrations.In low bromide concentration,BrO3-is formed only in high ozone dosage.Ozone dosage has great influence on the amount of total organic bromine (TOBr) on the percent conversion of Br-,but has no obvious effect on THMFP-Br.The generated BrO3-increases and the amount of TOBr decreases with the extended reaction time of ozonation.

Abstract:A urban water network was analyzed by the virtual reality technology in order to build a scene simulation platform of water network.And a new approach was appli on the study of water network system to overcome the shortcomings of traditional two-dimensional and three-dimensional models.The interaction and visual results were achieved in the virtual scene of the water network by integration of water network model and virtual scene.The objects in the virtual scene were built according to the standard atlas,which ensured that the model was with high accuracy.Then the model was optimized with relevant algorithms.The interactive virtual simulation platform of water network was built by programming in this paper and the scene simulation system of water network was realized,which was with the quality of verisimilitude,immersion and interaction.With the platform,the users can observe the water network lied underground directly,control the water network interactively and analyze the operation candition visually.

Abstract:In order to solve the problem of sludge bulking which happened in wastewater treatment plant frequently,a notion named low DO limited filamentous bulking was put forward.It is a new energy-saving and high-efficient method to treat wastewater with the characteristics of morphology and physiology of filamentous bacteria under low DO concentration condition.The impact of DO concentration and organic loading rate (OLR) on sludge settleability and the removal characteristics of nitrogen,phosphorus and COD under limited filamentous bulking were investigated by using sequencing batch reactor (SBR) through operation in aerobicanoxic pattern.The results show that OLR and DO concentration affect sludge settleability in special range respectively.When OLR is larger than 0.25 d-1,limited filamentous bulking state can not be maintained by low DO concentration alone.Nitrification will not be deteriorated under low DO limited filamentous bulking condition,and about 20% nitrogen is removed through simultaneous nitrification and denitrification (SND) based on the mass balance of nitrogen.Aerobic phosphorus release is found in the initial stage of low aeration rate,and the system can enrich phosphorus accumulating organisms (PAOs).

Abstract:To improve the biological activity of dominant bacteria on bio-enhanced activated carbon filter,five kinds of dominant bacteria,Pseudomonas balearica,Pseudomonas putida,Acinetobacter calcoaceticus,Acinetobacter lwoffii,and Brevibacterium mcbrellneri,which were isolated from Songhua River,were investigated for the enhanced biological activity.The effects of temperature,pH value,incubation time,DO value on the dehydrogenase activity variation of the dominant bacteria were studied in this paper.The results show that the dehydrogenase activity is high at 18 ℃,the pH value of 6,incubation time of 48 h and DO value of 7 mg/L,which is the optimal enhanced process for dominant bacteria.PCR-DGGE results show that the biomass of the dominant bacteria on activated carbon under the optimal enhanced process is more than that without the treatment of optimal enhanced process.

Abstract:Six strains with flocculent characteristic have been screened from oil-field wastewater,which are named as F1,F2,F3,F4,F5 and F6.They were identified and classified by 16SrDNA sequence.The flocculation species were analyzed through UV and IR scanning spectrophotometry.It is showed that the six strains belong to the same species with Balillus sp.,Agrobacterlum sp.,and Kocurla sp.and they have 99% homogeneous identity.The results of flocculent efficiency show that the flocculent efficiency of the six strains is more than 69%,among which the flocculent efficiencies of F2,F3,F5 and F6 are more than 80%.Mixed cultures were conducted pairwise among F2,F3,F5 and F6,and the results show that the combination of F2 and F6 strains exhibits the best flocculating efficiency and it is higher than that of any pure strain.

Abstract:According to the energy consumption status and roof insulation technical characteristics of rural housing in severe cold region,a double-layer composite roof insulation model for roof insulation and energysaving is proposed,which adapts to the contemporary rural housing roof features.The design of the model is described;a mathematical model of heat balance of the enclosed space under the ceiling of the pattern is set up,and the thickness of different reference insulation materials is given.The model proposed is a new design for rural housing roof insulation and energy-saving in severe cold region.

Abstract:To reduce the energy consumption of air-conditioning in summer and the initial investment of ground source heat pump,a novel seasonal soil cold storage system with natural energy is presented,and the transient heat transfer models of vertical U-tube and outdoor air exchanger are developed.The operating process of this system in Harbin is calculated using the sensitive heat capacity model.Five cold-storing modes are studied,and the cold-storing capacity,preliminary cold-storing time,cold-extracting capacity,cold-extracting temperature,COP and soil temperature field around tube under different modes are obtained.Simulation results show that the COP of system changes from 9.92 to 14.15,which indicates the notable energy-saving effect.The cold-extracting temperature and cold-extracting capacity can satisfy the needs of air-condition,and it is proved to be feasible for the application of the presented system in the cold area.

Abstract:Trip production forecast is one of key components of traffic demand analysis,which directly determines the scale and layout of different urban traffic facilities.The mechanism of artificial neural network (ANN) and influential factors of trip production were analyzed.therefore,a four-layer back-propagation neural network (BP neural network) model was set up to forecast the trip production,in which the input neurons are land-uses of different traffic zones and the output is trip production.Meanwhile,the model was calibrated and testified with traffic survey data from the urban integrative transportation planning of Ganzhou city.Furthermore,the results were compared with those obtained from trip production rate method and multiple linear regression method,It is showed that forecast precision of the BP neural network is relatively high.

Abstract:This paper presented a newly-developed analysis procedure for establishing equivalent single degree of freedom systems (ESDOF),based on the modal pushover analysis procedure with higher precision.The modal pushover analysis procedure was limited in terms of its inability to account for ground motion when establishing ESDOF.The suggested method overcomes the shortcoming.This method is characterized by its high efficiency of calculation and clear physical meaning,which eliminates the need to calculate modal combination step by step.And it was validated by calculating a shaking table test of a 12-storey reinforced concrete frame model.The structure model was calculated separately using nonlinear time history method,the method introduced herein and conventional modal pushover analysis procedure.Through the comparison of the calculation results,it was found that the higher-mode relative excited magnitude by ground motion is the main reason for modal coupling.And the suggested method yields higher precision than conventional modal pushover analysis procedure,especially for high frequency ground motion.So it has good adaptability.

Abstract:In order to research the influence of super-large cooling tower under earthquake excitation and wind load,the rigid model and aero-elastic model of a super-large cooling tower in the wind tunnel were employed,the data obtained in the test were loaded to calculate the structural response.By the comparison with the response under earthquake excitation,it is obvious that the responses of annular base and tower shell are completely controlled by wind load,and the value under wind load is much greater than that under earthquake excitation.Vertical and hoop forces of tower shell are diminished from the bottom to the top,and the maximums are found at the middle of the tower shell.Their influence on supporting columns is not obvious.300 modes should be considered in mode analysis method,while 30 modes are only considered when the structural response is calculated under wind load.

Abstract:By in-depth investigation and analysis of debris flows in Jinsha River watershed,the index values of several factors mainly the affecting hazardous areas of debris flow are extracted to predict the hazardous areas more objectively.The capability learning of improved BP neural network is used to predict the sensitivity of these factors.The slope of error curve is presented as the quantitative indicator of sensitivity.The factors affecting hazardous areas of various types of debris flows are assessed with the error coefficient and the conclusions are analyzed from the view of fluid mechanics.A new formula is proposed to improve the traditional forecasting model.In the example simulation,the improved model gets more accurate forecasting results.The difference between relative errors calculated by the improved model and the traditional model is 4.54 at most.

Abstract:Aimed at the cracking of concrete perforated brick wall,a practical analytical method was proposed,in which the equivalent fracture toughness was solved based on the vertical crack model.At first,based on the modified shear lag theory and by introducing the variable layer in different zones,the layered shear lag model was built.Then,an analytical form to solve the equivalent fracture toughness of concrete perforated brick wall was derived based on the energy law.The results of the related experiments show that the analytical solutions are more robust than the numerical solutions.In the case of varying sub-layers,the equivalent fracture toughness is a size-independent fracture parameter.So the suggested method is feasible and applicable to forecast concrete perforated brick masonry’s cracking and destroying.

Abstract:In order to study the flexural performance of members of steel tube filled with steel-reinforced highstrength concrete (STFSC),experimental and theoretical researches on the flexural behavior of 5 I shape of STFSC were carried out.The parameters in the study include the steel-reinforced index ρ=0.3-0.6 and different loading directions of steel-reinforce.The results indicate that bearing capacity of composite member nonlinearly increases with the increase of steel-reinforced index,but it linearly increases with the moment of inertia and the deformation of minor axis is bigger than that of major axis when the steel-reinforced index is determined.Composite member accords with plane section assumption,and the deflection of member fits for sine curve.The major axis of confining force of steel tube and steel-reinforce to concrete is more obvious than its minor axis,and the confining force is increased with the decrease of steel-reinforced index.Based on the experimental analysis,formula of bearing capacity of flexure is built,and a good agreement is obtained between calculating results and experimental results.

Abstract:In order to grasp the mechanism of the multi-girder structure during the whole course,the stress redistribution regularity is studied with shell element degraded from solid element.Steel and concrete are depicted by layered shell element and the prestressed steel is modeled by combined shell element.Then the stiffness matrix of contribution of the prestressed steel to the combined shell element is deduced.Respectively based on Owen yielding theory and Hinton crushing theory and bilinear model,the material nonlinear properties of concrete and steel are considered.Then the procession of cracking,yielding and failure of prestressed concrete multi-T girders is imitated and the analytical procedure is compiled.Through compared with the failure experiment results of a prestressed concrete multi-T girder bridge,the calculations are in good agreements with them.The regularity of stress redistribution of prestressed steel is studied.It shows that it is feasible to apply shell element degraded from solid element to depict the prestressed concrete multi-T girder bridge and the corresponding computational method and procedure for nonlinear whole-course analysis are correct and reliable.

Abstract:To quantify the variation of stress intensity factor to weld root flaw sizes in beam-to-column web connections,a methos that combines fracture mechanics and finite element analysis is presented.Fracture toughness demands were evaluated in terms of the Mode I stress intensity factor.The stress intensity factor was calculated through J-integral approach.The connection geometry was separately investigated in terms of the beam and column properties.The influences of the length of beam,column and beam flange plate on the stress intensity factor were analyzed.The fracture toughness demands were studied for the flaw on the top of the beam flange and the bottom surface,respectively.Finally,formulas for stress intensity factor were derived by orthogonal design.Results show that the deformation of panel zone has significant effects on stress intensity factor.The likelihood of top flange fractures is smaller than that of bottom flange fracture.Stress intensity factor increases with the increase of beam parameters and is reduced with the increase of column parameters.

Abstract:The effect of strong shock resistant capacity of the combined process of PPC preoxidation and BAC filtration was investigated in the treatment of surface water.The compared experimental results show that the organics removal rate in coagulation process and filtration process is enhanced and the steady running period in filtration process is shortened,which suggests that the combined processes of PPC preoxidation and biological activated carbon filtration have higher strong shock resistant capacity for organic matters and ammonia variation.In the case that raw water is polluted seriously,adding aeration process before biofilter process is an easy and effective way to enhance the biological process for organics removal.

Abstract:Aimed at the congestion evacuating,an available self-organizing signal control principle whithout signal cycle and fixed phase as well as phase order is proposed.The designed signal control method is based on inductive loop data to identify the congestion flow and will overcome the deficiency of the present signal control mode for controlling congested traffic flow.For maximizing the number of passing vehicles,the proposed signal control method includes some key components such as setting stand-by phases,weighting each stream,deciding the maximum waiting time and allocating signal timing.The method is tested and compared through simulation with VISSIM.The comparative analysis shows that the proposed method can evacuate the congested traffic flow of a congested intersection more effectively.

Abstract:In order to explore the feasibility of applying DC four-electrode method based on embedded gauze or loop electrode in electrical resistance measurement of conductive composites,DC four-electrode method and DC two-electrode method for electrical resistance measurement of composites with different matrices and conductive fillers were compared,and the calculation method of contact resistance between electrode and conductive composites was proposed and verified.Research results show that DC four-electrode method can eliminate contact resistance between electrode and conductive composites,which exists in DC two-electrode method.The contact resistance is non-ohmic and can be calculated,and its value depends on the property of measured conductive composites.DC four-electrode method based on embedded gauze or loop electrode is suitable for electrical resistance measurement of conductive composites.