The reliability and deterministic analyses of wood-cored stiffened deep cement mixing and deep cement mixing column-supported embankments(referred to as WSCSE and DCSE,respectively)considering serviceability limit sta...The reliability and deterministic analyses of wood-cored stiffened deep cement mixing and deep cement mixing column-supported embankments(referred to as WSCSE and DCSE,respectively)considering serviceability limit state requirements are presented in this paper.Random field theory was used to simulate the spatial variability of soilcement mixing(SCM)material in which the adaptive Kriging Monte Carlo simulation was adopted to estimate the failure probability of a columnsupported embankment(CSE)system.A new method for stochastically generating random values of unconfined compressive strength(qu)and the ratio(Ru)between the undrained elastic modulus and qu of SCM material based on statistical correlation data is proposed.Reliability performance of CSEs concerning changes in the mean(μ),coefficient of variation(CoV),and vertical spatial correlation length(θv)of qu and Ru are presented and discussed.The obtained results indicate that WSCSE can provide a significantly higher reliability level and can tolerate more SCM material spatial variability than DCSE.Some performance of DCSE and WSCSE,which can be considered satisfactory in a deterministic framework,cannot guarantee an acceptable reliability level from a probabilistic viewpoint.This highlights the importance and necessity of employing reliability analyses for the design of CSEs.Moreover,consideration of only μ and CoV of qu seems to be sufficient for reliability analysis of WSCSE while for DCSE,uncertainties regarding the Ru(i.e.both μ and CoV)and θv of qu cannot be ignored.展开更多
The consolidation behavior of mixed in place cement-and lime /cement-mixed column was studies.COnsolidation of the composite foundation was modeled as a three-dimensional axi-symmetric problem.The authors used the fin...The consolidation behavior of mixed in place cement-and lime /cement-mixed column was studies.COnsolidation of the composite foundation was modeled as a three-dimensional axi-symmetric problem.The authors used the finite difference method to obtain the pore pressure variation with time at and location below the surface.A computer program developed by the authors was used to draw some interesting conclusions about the consolidation behaviors of cement-mixed pile foundation.Finally,a combined model including the permeability coefficients of cement-mixed piles and soil,was studied and its feasibility was evaluated.展开更多
A new configuration of coalescence-dispersed pulsed-sieve-plate extraction column (CDPSEC) was developed, and the mass transfer and axial mixing characteristics were evaluated with the two-point dynamic method.The inf...A new configuration of coalescence-dispersed pulsed-sieve-plate extraction column (CDPSEC) was developed, and the mass transfer and axial mixing characteristics were evaluated with the two-point dynamic method.The influence of operation conditions was discussed with experimental results, showing that the mass transfer performance of CDPSEC mainly depends on the energy input and the holdup of dispersed phase. Higher energy input results in higher holdup of the dispersed phase, the axial mixing of the continuous phase is suppressed, and the true height of mass transfer unit decreases markedly. On the other hand, higher energy input leads to more serious forward mixing of the dispersed phase, so the energy input should be limited. Accordingly the operation conditions were divided into two regions, and empirical correlations for predicting the mass transfer and axial mixing characteristics in different regions with a satisfactory accuracy were suggested.展开更多
1 INTRODUCTIONAnnular pulsed-sieve-plate extraction column is an unique extraction equipment that can beused to ensure critical safety in reprocssing of irradiated nuclear fuel,The study of this kind ofextraction colu...1 INTRODUCTIONAnnular pulsed-sieve-plate extraction column is an unique extraction equipment that can beused to ensure critical safety in reprocssing of irradiated nuclear fuel,The study of this kind ofextraction column has been carried out and some results were published in resent years [1—9]. It is known that axial mixing is one of most important parameters effecting column be-展开更多
This research is conducted to study the experimental behavior of composite steel-concrete columns with basalt additives. Various percentages of basalt are added to the concrete mixes to investigate its effect on the t...This research is conducted to study the experimental behavior of composite steel-concrete columns with basalt additives. Various percentages of basalt are added to the concrete mixes to investigate its effect on the total axial compressive capacity of the columns. Expected failure scenarios of the columns are: concrete compressive failure, buckling of steel section, and de-bonding between steel and concrete sections. A conventional limestone composite column was used as base mix. The results of the study indicate a significant improvement in structural behavior and strength of the columns by increasing the percentage of basalt content.展开更多
To evaluate the influence of gas and liquid axial mixings on the separation efficiency of packed column, an approximate mathematical solution of HETP (equivalent height to a theoretical plate) under continuous operati...To evaluate the influence of gas and liquid axial mixings on the separation efficiency of packed column, an approximate mathematical solution of HETP (equivalent height to a theoretical plate) under continuous operation has been proposed based on the mixing pool model. The mass transfer and hydrodynamic data of structured packing, Mellapak 350Y, obtained in a high pressure tower have been used to test the validity of the proposed model. Compared with the SRP model and the Gualito model, it is found that for high pressure distillation process the present mathematical prediction shows a mean relative error of about 10% to the experimental data,the accuracy of which is the same as that by the Gualito model but better than that by the SRP model.展开更多
A packed flotation column, which is packed with multiple board ripple packings, was described. Based on comprehensive steady state models, chemical reactor developed previously in chemical engineering subjects, have b...A packed flotation column, which is packed with multiple board ripple packings, was described. Based on comprehensive steady state models, chemical reactor developed previously in chemical engineering subjects, have been extended to packed flotation column for mineral separation. The experimental results verify that tanks in series model is better than axially dispersed plug flow model to describe flow pattern in the collection zone of column by RTD (residence time distribution), and the error of experimental data and calculated data of both models are 0.07% ～ 0.1% and 0.18% ～ 0.45% respectively. And, RTD of gas phase was also considered, results also show that gas in the whole column appears plug flow. The cleaning process through adding wash water in froth zone of column was described, and the effect of superficial air velocity and superficial wash water velocity on the cleaning action of froth zone were discussed. Flotation experiment for single column was conducted for phosphate ores. The recovery for P 2O 5 was 85.8%, and the grade was 26.8%.展开更多
A theoretical analysis of the effects of flow and mixing on the operating features of astirred column reactor(SCR)with multistage mixers and cooling partition plates was conducted.Amethod for calculating the concentra...A theoretical analysis of the effects of flow and mixing on the operating features of astirred column reactor(SCR)with multistage mixers and cooling partition plates was conducted.Amethod for calculating the concentration reduction for a second order chemical reaction in a SCRwas proposed.The reactants concerned were pre-mixed before feeding into the SCR.The SCR wascomposed of a number of stages with interstage backmixing.Experimental investigation with variousreaction media were carried out in order to study the effect of mixing on the operational performanceof the SCR.The experimental data were compared with the theoretical results.展开更多
The open turbine rotating disc contactor (OTRDC) has been installed simply by adding three narrow strips to the lower surface of each rotating disc in the rotating disc contactor (RDC), so it can be used for the syste...The open turbine rotating disc contactor (OTRDC) has been installed simply by adding three narrow strips to the lower surface of each rotating disc in the rotating disc contactor (RDC), so it can be used for the system with high solid particle content. Hydrodynamics and axial mixing have been investigated in a 0.152m diameter OTRDC of different compartment height for the system of tap water and quartz particles. A model has been developed to describe the flow of liquid and solid phases. The solid phase holdup can be calculated satisfactorily according to the model equations. Axial mixing data have been treated by the backflow model and the correlations for predicting backflow ratios of liquid and solid phases in OTRDC have been presented.展开更多
Features of the motion of gel particles in a three-phase bubble column with non-foaming and foaming gas–liquid systems,determined by using experiments of radioactive particle tracking(RPT),have been compared.The trac...Features of the motion of gel particles in a three-phase bubble column with non-foaming and foaming gas–liquid systems,determined by using experiments of radioactive particle tracking(RPT),have been compared.The tracer used is a gel particle which resembles typical immobilized biocatalyst.The tracer trajectory is analyzed to extract relevant information for design purposes.The solid velocity field,turbulence parameters,dispersion coefficients,mixing times and flow transitions are determined and compared.The presence of foam significantly affects many quantified parameters,especially within the heterogeneous flow regime.The hydrodynamic stresses are reduced in the presence of foam,especially close to the disengagement.The dispersion coefficients also decrease,and the solid mixing time is only slightly affected by the presence of foam.Gas holdup,inferred both from RPT experiments and from gamma ray scanning,is higher for foaming systems and leads to a shift in the transition gas velocity towards higher values.展开更多
文摘The reliability and deterministic analyses of wood-cored stiffened deep cement mixing and deep cement mixing column-supported embankments(referred to as WSCSE and DCSE,respectively)considering serviceability limit state requirements are presented in this paper.Random field theory was used to simulate the spatial variability of soilcement mixing(SCM)material in which the adaptive Kriging Monte Carlo simulation was adopted to estimate the failure probability of a columnsupported embankment(CSE)system.A new method for stochastically generating random values of unconfined compressive strength(qu)and the ratio(Ru)between the undrained elastic modulus and qu of SCM material based on statistical correlation data is proposed.Reliability performance of CSEs concerning changes in the mean(μ),coefficient of variation(CoV),and vertical spatial correlation length(θv)of qu and Ru are presented and discussed.The obtained results indicate that WSCSE can provide a significantly higher reliability level and can tolerate more SCM material spatial variability than DCSE.Some performance of DCSE and WSCSE,which can be considered satisfactory in a deterministic framework,cannot guarantee an acceptable reliability level from a probabilistic viewpoint.This highlights the importance and necessity of employing reliability analyses for the design of CSEs.Moreover,consideration of only μ and CoV of qu seems to be sufficient for reliability analysis of WSCSE while for DCSE,uncertainties regarding the Ru(i.e.both μ and CoV)and θv of qu cannot be ignored.
文摘The consolidation behavior of mixed in place cement-and lime /cement-mixed column was studies.COnsolidation of the composite foundation was modeled as a three-dimensional axi-symmetric problem.The authors used the finite difference method to obtain the pore pressure variation with time at and location below the surface.A computer program developed by the authors was used to draw some interesting conclusions about the consolidation behaviors of cement-mixed pile foundation.Finally,a combined model including the permeability coefficients of cement-mixed piles and soil,was studied and its feasibility was evaluated.
文摘A new configuration of coalescence-dispersed pulsed-sieve-plate extraction column (CDPSEC) was developed, and the mass transfer and axial mixing characteristics were evaluated with the two-point dynamic method.The influence of operation conditions was discussed with experimental results, showing that the mass transfer performance of CDPSEC mainly depends on the energy input and the holdup of dispersed phase. Higher energy input results in higher holdup of the dispersed phase, the axial mixing of the continuous phase is suppressed, and the true height of mass transfer unit decreases markedly. On the other hand, higher energy input leads to more serious forward mixing of the dispersed phase, so the energy input should be limited. Accordingly the operation conditions were divided into two regions, and empirical correlations for predicting the mass transfer and axial mixing characteristics in different regions with a satisfactory accuracy were suggested.
文摘1 INTRODUCTIONAnnular pulsed-sieve-plate extraction column is an unique extraction equipment that can beused to ensure critical safety in reprocssing of irradiated nuclear fuel,The study of this kind ofextraction column has been carried out and some results were published in resent years [1—9]. It is known that axial mixing is one of most important parameters effecting column be-
基金Project(50621063)supported by the National Natural Science Foundation of ChinaProject(2004CB619205)supported by the National Basic Research Program of ChinaProject(2007AA060902)supported by the High-tech Research and Development Program of China
文摘This research is conducted to study the experimental behavior of composite steel-concrete columns with basalt additives. Various percentages of basalt are added to the concrete mixes to investigate its effect on the total axial compressive capacity of the columns. Expected failure scenarios of the columns are: concrete compressive failure, buckling of steel section, and de-bonding between steel and concrete sections. A conventional limestone composite column was used as base mix. The results of the study indicate a significant improvement in structural behavior and strength of the columns by increasing the percentage of basalt content.
文摘To evaluate the influence of gas and liquid axial mixings on the separation efficiency of packed column, an approximate mathematical solution of HETP (equivalent height to a theoretical plate) under continuous operation has been proposed based on the mixing pool model. The mass transfer and hydrodynamic data of structured packing, Mellapak 350Y, obtained in a high pressure tower have been used to test the validity of the proposed model. Compared with the SRP model and the Gualito model, it is found that for high pressure distillation process the present mathematical prediction shows a mean relative error of about 10% to the experimental data,the accuracy of which is the same as that by the Gualito model but better than that by the SRP model.
文摘A packed flotation column, which is packed with multiple board ripple packings, was described. Based on comprehensive steady state models, chemical reactor developed previously in chemical engineering subjects, have been extended to packed flotation column for mineral separation. The experimental results verify that tanks in series model is better than axially dispersed plug flow model to describe flow pattern in the collection zone of column by RTD (residence time distribution), and the error of experimental data and calculated data of both models are 0.07% ～ 0.1% and 0.18% ～ 0.45% respectively. And, RTD of gas phase was also considered, results also show that gas in the whole column appears plug flow. The cleaning process through adding wash water in froth zone of column was described, and the effect of superficial air velocity and superficial wash water velocity on the cleaning action of froth zone were discussed. Flotation experiment for single column was conducted for phosphate ores. The recovery for P 2O 5 was 85.8%, and the grade was 26.8%.
基金Supported by the National Natural Science Fundation of China.
文摘A theoretical analysis of the effects of flow and mixing on the operating features of astirred column reactor(SCR)with multistage mixers and cooling partition plates was conducted.Amethod for calculating the concentration reduction for a second order chemical reaction in a SCRwas proposed.The reactants concerned were pre-mixed before feeding into the SCR.The SCR wascomposed of a number of stages with interstage backmixing.Experimental investigation with variousreaction media were carried out in order to study the effect of mixing on the operational performanceof the SCR.The experimental data were compared with the theoretical results.
文摘The open turbine rotating disc contactor (OTRDC) has been installed simply by adding three narrow strips to the lower surface of each rotating disc in the rotating disc contactor (RDC), so it can be used for the system with high solid particle content. Hydrodynamics and axial mixing have been investigated in a 0.152m diameter OTRDC of different compartment height for the system of tap water and quartz particles. A model has been developed to describe the flow of liquid and solid phases. The solid phase holdup can be calculated satisfactorily according to the model equations. Axial mixing data have been treated by the backflow model and the correlations for predicting backflow ratios of liquid and solid phases in OTRDC have been presented.
基金Supported by the FONCyT(PICT2014-0704)CONICET(PIP1122015-0100902CO)Universidad de Buenos Aires(UBACyT 20020130100544BA)
文摘Features of the motion of gel particles in a three-phase bubble column with non-foaming and foaming gas–liquid systems,determined by using experiments of radioactive particle tracking(RPT),have been compared.The tracer used is a gel particle which resembles typical immobilized biocatalyst.The tracer trajectory is analyzed to extract relevant information for design purposes.The solid velocity field,turbulence parameters,dispersion coefficients,mixing times and flow transitions are determined and compared.The presence of foam significantly affects many quantified parameters,especially within the heterogeneous flow regime.The hydrodynamic stresses are reduced in the presence of foam,especially close to the disengagement.The dispersion coefficients also decrease,and the solid mixing time is only slightly affected by the presence of foam.Gas holdup,inferred both from RPT experiments and from gamma ray scanning,is higher for foaming systems and leads to a shift in the transition gas velocity towards higher values.
