Pressurized bentonite slurry is applied on a tunnel face to form a filter cake to stabilize the tunnel face when the slurryshield excavates through the sandy soil. Failure of the tunnel face may be caused by a high pe...Pressurized bentonite slurry is applied on a tunnel face to form a filter cake to stabilize the tunnel face when the slurryshield excavates through the sandy soil. Failure of the tunnel face may be caused by a high permeable filter cake, which commonlyhas a long penetration distance of slurry in sands. A column system with a height of 680 mm and a diameter of 300 mm was de-veloped to model pressurized slurry infiltration in sands. Pressure transducers were installed to estimate the hydraulic conductivityof the filter cake during slurry infiltration. The electrical conductivity of the leachate of collected samples was measured. Resultsshow that the majority of fine particles in slurry are within the range 100-300 mm into the sand specimen. The time for forming animpermeable filter cake is about 300 s, which indicates the impermeable filter cake is hard to form during the excavation.展开更多
The ozone over the Tibetan Plateau(TP)plays an important role in protecting the local ecology by absorbing ultraviolet solar rays.The El Nino-Southern Oscillation(ENSO),recognized as the strongest interannual climate ...The ozone over the Tibetan Plateau(TP)plays an important role in protecting the local ecology by absorbing ultraviolet solar rays.The El Nino-Southern Oscillation(ENSO),recognized as the strongest interannual climate phenomenon globally,can create ozone variations over the TP.Based on the historical experimental simulation results of two Community Earth System Models(i.e.CESM2-WACCM and CESM2-WACCM-FV2)that include the coupling process of stratospheric chemistry-radiation-dynamics,this study analyzes the impact of ENSO on the wintertime total ozone column(TCO)over the TP,as well as its physical processes,from 1979 to 2014.When compared to observations,the results show that the two models can basically simulate the spatial distribution of the climate state and standard deviation of the TP TCO.In the two models,CESM2-WACCM performs better.During the winter when the ENSO signal is strongest,its warm phase,El Nino,cools the tropospheric temperature over the TP by modifying the atmospheric circulation,which induces a decrease in the tropopause height.Such decreases in the tropopause height are responsible for the TP TCO increase.The cool phase La Nina is responsible for a TCO decrease over the TP,in a manner resembling the El Nino but with the opposite signal.Our results are consistent with previous observational analysis,and the relevant research provides valuable scientific insights for evaluating and improving the Earth System Model that incorporates the coupling process of stratospheric chemistry-radiation-dynamics.展开更多
Acetylspiramycin（ASPM）,a 16-membered basic macrolide antibiotic,is the acetylated derivative of spiramycin.In addition to the four main components,more than seventy minor components could be present in ASPM.Thus,it ...Acetylspiramycin（ASPM）,a 16-membered basic macrolide antibiotic,is the acetylated derivative of spiramycin.In addition to the four main components,more than seventy minor components could be present in ASPM.Thus,it is a challenge to obtain a baseline separation of ASPM components.Meanwhile,in some cases it was found that the results obtained by different brands of C_（18） columns were significantly different,indicating the necessity of a rational column selection for the separation of ASPM components.In this paper,we attempted to facilitate column selection for the analysis of ASPM using the database of the column characterization system established by Leuven University.With the CAPCELL PAK MG C_（18）（250 mm×4.6 mm,5μm） as the reference column,three groups of columns（F2 group：similar selectivity;2F6：intermediate ranked group;F6 group： different selectivity,compared to the reference column） were selected,and their performances in the separation of ASPM components were evaluated under the chromatographic conditions described in Chinese Pharmacopoeia monograph.A good relationship was demonstrated between the ranking of columns and their selectivity in the separation of ASPM components,indicating the column classification system established by Leuven University was a helpful tool in the selection of suitable columns for the analysis of ASPM,a complex mixture of basic compounds.展开更多
Inverted batch distillation column(stripper) is opposed to a conventional batch distillation col-umn(rectifier). It has a storage vessel at the top and products leave the column at the bottom. The batch stripper is fa...Inverted batch distillation column(stripper) is opposed to a conventional batch distillation col-umn(rectifier). It has a storage vessel at the top and products leave the column at the bottom. The batch stripper is favourable to separate mixtures with a small amount of light components by removing the heavy components as bottom products. In this paper, we are presenting a shortcut procedure based on our earlier work for design and simulation of the inverted batch distillation column, which is equivalent to the Fenske-Underwood-Gilliland procedure for continuous distillation. Given a separation task, we propose to compute the minimum number of stages(Nbmin) and the minimum reboil ratio(Rbmin) required in a batch stripper,which are the stages and reboil ratio required in a hypothetical inverted batch distillation column operating in total reboil ratio or having an infinite number of stages, respectively. Then, it is shown that the performance of inverted batch columns with a finite number of stages and reboil ratios could be correlated in Gilliland coordinates with the minimum stages Nbmin and the minimum reboil ratio Rbmin.展开更多
Through separation of the hexane-heptane–octane system in a cross-wall adiabatic dividing wall column, the effects of feed position, side-draw position, liquid split ratio, vapor split ratio and their interactions on...Through separation of the hexane-heptane–octane system in a cross-wall adiabatic dividing wall column, the effects of feed position, side-draw position, liquid split ratio, vapor split ratio and their interactions on the energy consumption were analyzed by Aspen Plus under the constant product purity, and the response surface model for the energy consumption was regressed. Based on the restriction on the optimal operating zone, the comparison of different combinations of surrogate models and optimization methods showed that, the combination of the Kriging model and multi-island genetic algorithm(Kriging-MIGA) had better prediction ability than the combination of the response surface model and partial derivative method(RSM-PD), and RSM-PD had better optimization effect than Kriging-MIGA. With a self-made cross-wall adiabatic dividing wall column, the temperature at measuring points and the energy consumption were measured during experiments, the comparison between measured values and simulated ones demonstrated that the optimized values of variables searched by RSM-PD and Kriging-MIGA could be both used as the optimum technological conditions since the experimental reliability was ensured, with the optimum technological conditions shown below: The feed position is 6, the side-draw position is 7, the combinations of liquid split ratio and vapor split ratio are [0.14, 0.5] and [0.16, 0.52], respectively. RSM-PD and Kriging-MIGA can provide the appropriate optimization methods for the dividing wall column.展开更多
This paper presents the experimental and numerical studies conducted on a steel column and a steel frame structure using free vibration analysis.The effects of damages on structures were investigated,which were simula...This paper presents the experimental and numerical studies conducted on a steel column and a steel frame structure using free vibration analysis.The effects of damages on structures were investigated,which were simulated by introducing multiple cracks at different locations in the experimental and numerical models.The acceleration responses of the test models,were recorded through an accelerometer,and were used to calibrate the numerical models developed in finite element based software.Modal frequencies of damaged and undamaged structures were compared and analyzed,to derive relationships for damaged and undamaged structures’frequencies in terms of crack depth.It was found that,due to the presence of cracks,the mechanical properties of a structure changes,whereby,the modal frequencies decrease.An approximately linear trend was observed for the frequency decrease with the increase in crack depth,which was also confirmed by the numerical models.The derived relationships were extended to further develop a mechanics-based damage scale for steel structures,to help facilitate structural health monitoring and screening of vulnerable structures.展开更多
The strategy of expert system for high performance liquid chromatography was discussed, the attentions are mainly placed on the knowledge base for selection of column system, separation modes and detection modes in th...The strategy of expert system for high performance liquid chromatography was discussed, the attentions are mainly placed on the knowledge base for selection of column system, separation modes and detection modes in the analysis of amino acids, peptides and proteins.展开更多
The column bioleaching of copper flotation tailings was comparatively investigated using layered heap construction method(LM),agglomerate heap construction method(AM),and pellets-sintering heap construction method(PM)...The column bioleaching of copper flotation tailings was comparatively investigated using layered heap construction method(LM),agglomerate heap construction method(AM),and pellets-sintering heap construction method(PM).The bacterial communities of free,attached,weakly-attached,and strongly-attached microbes in the later bioleaching stage were investigated.In AM group,the addition of lump sulphide ore resulted in the low leachate pH,high ferric iron concentration,and rapid microbial adsorption,which obtained the maximum copper extraction(60.1%)compared with LM(54.6%)and PM(43.9%)groups.The relative abundance of dominant genera and microbial communities of different microbiota underwent changes in three heap construction methods.The alpha-diversity indexes of attached,weakly-attached,and strongly-attached microbes were different,while no significant change was observed in free bacteria.The variation of whole bacterial community was significantly associated with solution pH,total iron,and ferric iron concentrations.Pearson correlation analysis and partial least square path model both indicated that attached bacteria made larger contribution to the copper extraction of tailings.展开更多
Overall dispersed side volumetric mass transfer coefficients for protein and amino acids were measured in continuous countercurrent PEG4000/KHP aqueous two-phase systems in a 57mm I.D. packed extraction column. A mode...Overall dispersed side volumetric mass transfer coefficients for protein and amino acids were measured in continuous countercurrent PEG4000/KHP aqueous two-phase systems in a 57mm I.D. packed extraction column. A model for overall dispersed side volumetric mass transfer coefficients was derived by describing the motion of the drops based upon Navier-Stokes equation combined with the relationship between mass transfer coefficients and the drop velocity. The model provides good predictions and can be successfully used in aqueous two-phase extraction. The average relative deviation between calculated values and experimental data ranges from 8% to 14%.展开更多
For N-component distillation(N≥3),consolidation between different column sections is an inevitable manipulation when synthesizing complex distillation configurations.In the consolidation,the idiomatic vapor balance(I...For N-component distillation(N≥3),consolidation between different column sections is an inevitable manipulation when synthesizing complex distillation configurations.In the consolidation,the idiomatic vapor balance(IVB)rule,in which the larger vapor flowrate in the two columns before consolidation will be chosen as the balanced vapor flowrate at the consolidation point,has been widely used.However,the applicability of the IVB rule has not been verified,which is of essential importance to the accuracy of the distillation configuration synthesis.In the present study,the applicability of the IVB rule to distillation column consolidation was systematically explored by rigorous method for the first time.First,the separation of ideal and non-ideal three-component mixtures with variable compositions was studied,and the optimized configurations before and after consolidation were determined by a rigorous method.The results indicated that for the separation of an ideal mixture,the IVB rule was applicable for the whole composition range,while for the separation of a non-ideal mixture,the IVB rule was only applicable for very limited composition range.Finally,two cases of synthesizing distillation configurations for the separation of non-ideal mixtures were studied to verify the remarkable deviations the IVB rule may cause.The results indicated that the applicability of the shortcut method using the IVB rule to the distillation configuration synthesis depended on the composition of the non-ideal mixture,and a remarkable error might result and the truly optimal configuration might be missed if the IVB rule is applied to a non-ideal mixture.展开更多
Methacrylate-based monolithic column was prepared in fused-silica capillary (80 ′ 0.32 mm i.d.) by in situ polymerizetion reaction using glycidyl methacrylate as monomer;ethylene dimethacrylate as crosslinker;1-propa...Methacrylate-based monolithic column was prepared in fused-silica capillary (80 ′ 0.32 mm i.d.) by in situ polymerizetion reaction using glycidyl methacrylate as monomer;ethylene dimethacrylate as crosslinker;1-propanol, 1,4-butanediol, and water as porogenic solvents. The monolith matrix was modified with trimethylamine to create strong anion exchanger via ring opening reaction of epoxy groups. The morphology of the monolithic column was studied by using Scanning Electron Microscope (SEM). This column had good mechanical stability and permeability. The effects of various mobile phases for separation of inorganic anions were investigated. Iodate, bromate, nitrite, bromide, and nitrate were separated within 11 min using100 mMpotassium chloride as mobile phase and detected at 210 nm. This method showed good precision of retention time, acceptable linearity and good sensitivity. Under the optimum condition, the RSD of the retention time was in the range of 1.09%-1.75% (n = 6). The calibration curve showed linear relationships between the peak area and the concentration. The limits of detection (LOD) and the limits of quantitation (LOQ) were between 0.08-0.18 mM and 0.26-0.61 mM, respectively. This method was applied to the determination of inorganic anions in tap water and ground water samples.展开更多
For achieving optimized jet grout parameters and W/C ratio it is concluded to set trial tests in constant local soil as the conclusion depends on local soil and presence of the extensive range of the effective paramet...For achieving optimized jet grout parameters and W/C ratio it is concluded to set trial tests in constant local soil as the conclusion depends on local soil and presence of the extensive range of the effective parameters. Considering the benefits, due to abundance of the involved variables and the intrinsic geological complexity, this system follows a great expense in the trial and implementation phases. Utilizing the soft computing methods, this paper proposes a new approach to reduce or to eliminate the cost of the trial phase. Therefore, the Adaptive Neuro Fuzzy Inference System (ANFIS) was utilized to study the possibility of anticipating the diameter of the jet grout (Soilcrete) columns on the trial phase based on the Trial and Error procedure. Data were collected from several projects and formed three sets of data. Consequently, parameters were held constant (as input) and the diameters of the Soilcrete columns were recorded (as output). To increase the precision, aforementioned data sets were combined and ten different data sets were created and studied, with all the results being assessed in two different approaches. Accordingly, Gaussian Function results in a huge number of precise and acceptable outcomes among available functions. Based on the measurements, Gaussian Function achieves the values of the R which are frequently more than 0.8 and lower values of the RMSE. Therefore, utilizing Gaussian Function, mainly a congruent relation between the R and RMSE is experienced and it leads to close proximity of the actual and predicted values of the Soilcrete diameter.展开更多
This paper presents a comprehensive review of various traditional systems of crude oil distillation column design, modeling, simulation, optimization and control methods. Artificial neural network (ANN), fuzzy logic (...This paper presents a comprehensive review of various traditional systems of crude oil distillation column design, modeling, simulation, optimization and control methods. Artificial neural network (ANN), fuzzy logic (FL) and genetic algorithm (GA) framework were chosen as the best methodologies for design, optimization and control of crude oil distillation column. It was discovered that many past researchers used rigorous simulations which led to convergence problems that were time consuming. The use of dynamic mathematical models was also challenging as these models were also time dependent. The proposed methodologies use back-propagation algorithm to replace the convergence problem using error minimal method.展开更多
The recommendation of column system (RCS) is the most important component of the expert system of chromatography. The system which we studied and built is a software package based on the theory devdoped for many years...The recommendation of column system (RCS) is the most important component of the expert system of chromatography. The system which we studied and built is a software package based on the theory devdoped for many years. The most fundamental theoretical base is the quantitative relationship between molecular structure parameters and the retention value of the solute:展开更多
An object-oriented prototype expert system ORDEES for off-line trouble-shooting of refinery distillation columns is developed. It is found that highly modular knowledge base can be designed, and different types of dat...An object-oriented prototype expert system ORDEES for off-line trouble-shooting of refinery distillation columns is developed. It is found that highly modular knowledge base can be designed, and different types of data (e.g., graphs, numberical data, and algorithms) may be manipulated, by using object-oriented knowledge representation. In addition, a method termed Object-Oriented Multifunction Switcher is proposed for building multifunction expert systems. The results of the study are expected to be useful for designing multifunction expert systems for complex petroleum refining and petro-chemical processes with many kinds of equipment.展开更多
Base on industrial research and experience, the process of methanol distillation is analyzed,and above all, a new concept of high pressure flowsheet and low pressure flowsheet is defined. The new configuration helps t...Base on industrial research and experience, the process of methanol distillation is analyzed,and above all, a new concept of high pressure flowsheet and low pressure flowsheet is defined. The new configuration helps to handle problems encountered in many factories in China. The inter influence between process and column internal pattern is also pointed out. Recommendation of new column internal designs is given. Finally, industrial examples tell the how the new concept works and the possibility of combining process to give more opens to solve engineering problems.展开更多
This research work investigated comparative studies of expert system design and control of crude oil distillation column (CODC) using artificial neural networks based Monte Carlo (ANNBMC) simulation of random processe...This research work investigated comparative studies of expert system design and control of crude oil distillation column (CODC) using artificial neural networks based Monte Carlo (ANNBMC) simulation of random processes and artificial neural networks (ANN) model which were validated using experimental data obtained from functioning crude oil distillation column of Port-Harcourt Refinery, Nigeria by MATLAB computer program. Ninety percent (90%) of the experimental data sets were used for training while ten percent (10%) were used for testing the networks. The maximum relative errors between the experimental and calculated data obtained from the output variables of the neural network for CODC design were 1.98 error % and 0.57 error % when ANN only and ANNBMC were used respectively while their respective values for the maximum relative error were 0.346 error % and 0.124 error % when they were used for the controller prediction. Larger number of iteration steps of below 2500 and 5000 were required to achieve convergence of less than 10-7?for the training error using ANNBMC for both the design of the CODC and controller respectively while less than 400 and 700 iteration steps were needed to achieve convergence of 10-4?using ANN only. The linear regression analysis performed revealed the minimum and maximum prediction accuracies to be 80.65% and 98.79%;and 98.38% and 99.98% when ANN and ANNBMC were used for the CODC design respectively. Also, the minimum and maximum prediction accuracies were 92.83% and 99.34%;and 98.89% and 99.71% when ANN and ANNBMC were used for the CODC controller respectively as both methodologies have excellent predictions. Hence, artificial neural networks based Monte Carlo simulation is an effective and better tool for the design and control of crude oil distillation column.展开更多
This paper presents the design of a robust control system for a high-purity distillation column. It is concerned with the design of a two degree-of-freedom (2DOF) product-composition controller for a high-purity disti...This paper presents the design of a robust control system for a high-purity distillation column. It is concerned with the design of a two degree-of-freedom (2DOF) product-composition controller for a high-purity distillation column. The H<sub>∞</sub> optimization problem is set up to ensure a guaranteed level of robust stability, robust disturbance attenuation and robust reference tracking performance.展开更多
In the task of inspecting underwater suspended pipelines,multi-beam sonar(MBS)can provide two-dimensional water column images(WCIs).However,systematic interferences(e.g.,sidelobe effects)may induce misdetection in WCI...In the task of inspecting underwater suspended pipelines,multi-beam sonar(MBS)can provide two-dimensional water column images(WCIs).However,systematic interferences(e.g.,sidelobe effects)may induce misdetection in WCIs.To address this issue and improve the accuracy of detection,we developed a density-based clustering method for three-dimensional water column point clouds.During the processing of WCIs,sidelobe effects are mitigated using a bilateral filter and brightness transformation.The cross-sectional point cloud of the pipeline is then extracted by using the Canny operator.In the detection phase,the target is identified by using density-based spatial clustering of applications with noise(DBSCAN).However,the selection of appropriate DBSCAN parameters is obscured by the uneven distribution of the water column point cloud.To overcome this,we propose an improved DBSCAN based on a parameter interval estimation method(PIE-DBSCAN).First,kernel density estimation(KDE)is used to determine the candidate interval of parameters,after which the exact cluster number is determined via density peak clustering(DPC).Finally,the optimal parameters are selected by comparing the mean silhouette coefficients.To validate the performance of PIE-DBSCAN,we collected water column point clouds from an anechoic tank and the South China Sea.PIE-DBSCAN successfully detected both the target points of the suspended pipeline and non-target points on the seafloor surface.Compared to the K-Means and Mean-Shift algorithms,PIE-DBSCAN demonstrates superior clustering performance and shows feasibility in practical applications.展开更多
The behavior of reinforced concrete(RC)square columns strengthened with self-compacting concrete(SCC)-filled steel tubes under cyclic loading was experimentally investigated.Tests were carried out on eleven reinforced...The behavior of reinforced concrete(RC)square columns strengthened with self-compacting concrete(SCC)-filled steel tubes under cyclic loading was experimentally investigated.Tests were carried out on eleven reinforced columns and one unreinforced column.The parameters studied for the strengthened columns included axial compression ratio,reinforcement rate,defect rate,strength of SCC,and the section form of a reinforced steel tube.The results show that the steel tube SCC reinforcement method can effectively strengthen RC columns,exert the restraint effect of steel tube,and delay the development of internal concrete cracks.The method can also significantly improve the bearing capacity of RC columns.Regarding ductility,the improvement of the reinforced column is obvious,the deformation resistance of the specimen is enhanced,and the degradation of stiffness and strength is relatively slow,indicating that it has good seismic performance.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51225804,U1234204,and 41472244)the Doctoral Fund of the Ministry of Education of China(No.20120101110027)+1 种基金the Research Fund from the China Railway Corporation(No.2014G003-B)the Zhejiang Provincial Communication Department(No.2014H07),China
文摘Pressurized bentonite slurry is applied on a tunnel face to form a filter cake to stabilize the tunnel face when the slurryshield excavates through the sandy soil. Failure of the tunnel face may be caused by a high permeable filter cake, which commonlyhas a long penetration distance of slurry in sands. A column system with a height of 680 mm and a diameter of 300 mm was de-veloped to model pressurized slurry infiltration in sands. Pressure transducers were installed to estimate the hydraulic conductivityof the filter cake during slurry infiltration. The electrical conductivity of the leachate of collected samples was measured. Resultsshow that the majority of fine particles in slurry are within the range 100-300 mm into the sand specimen. The time for forming animpermeable filter cake is about 300 s, which indicates the impermeable filter cake is hard to form during the excavation.
基金jointly supported by the National Natural Science Foundation of China(grant Nos.U2442210,42175042,42275059)the Natural Science Foundation of Sichuan Province(grant Nos.2024NSFTD0017,2023NSFSC0246)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0103)。
文摘The ozone over the Tibetan Plateau(TP)plays an important role in protecting the local ecology by absorbing ultraviolet solar rays.The El Nino-Southern Oscillation(ENSO),recognized as the strongest interannual climate phenomenon globally,can create ozone variations over the TP.Based on the historical experimental simulation results of two Community Earth System Models(i.e.CESM2-WACCM and CESM2-WACCM-FV2)that include the coupling process of stratospheric chemistry-radiation-dynamics,this study analyzes the impact of ENSO on the wintertime total ozone column(TCO)over the TP,as well as its physical processes,from 1979 to 2014.When compared to observations,the results show that the two models can basically simulate the spatial distribution of the climate state and standard deviation of the TP TCO.In the two models,CESM2-WACCM performs better.During the winter when the ENSO signal is strongest,its warm phase,El Nino,cools the tropospheric temperature over the TP by modifying the atmospheric circulation,which induces a decrease in the tropopause height.Such decreases in the tropopause height are responsible for the TP TCO increase.The cool phase La Nina is responsible for a TCO decrease over the TP,in a manner resembling the El Nino but with the opposite signal.Our results are consistent with previous observational analysis,and the relevant research provides valuable scientific insights for evaluating and improving the Earth System Model that incorporates the coupling process of stratospheric chemistry-radiation-dynamics.
文摘Acetylspiramycin（ASPM）,a 16-membered basic macrolide antibiotic,is the acetylated derivative of spiramycin.In addition to the four main components,more than seventy minor components could be present in ASPM.Thus,it is a challenge to obtain a baseline separation of ASPM components.Meanwhile,in some cases it was found that the results obtained by different brands of C_（18） columns were significantly different,indicating the necessity of a rational column selection for the separation of ASPM components.In this paper,we attempted to facilitate column selection for the analysis of ASPM using the database of the column characterization system established by Leuven University.With the CAPCELL PAK MG C_（18）（250 mm×4.6 mm,5μm） as the reference column,three groups of columns（F2 group：similar selectivity;2F6：intermediate ranked group;F6 group： different selectivity,compared to the reference column） were selected,and their performances in the separation of ASPM components were evaluated under the chromatographic conditions described in Chinese Pharmacopoeia monograph.A good relationship was demonstrated between the ranking of columns and their selectivity in the separation of ASPM components,indicating the column classification system established by Leuven University was a helpful tool in the selection of suitable columns for the analysis of ASPM,a complex mixture of basic compounds.
文摘Inverted batch distillation column(stripper) is opposed to a conventional batch distillation col-umn(rectifier). It has a storage vessel at the top and products leave the column at the bottom. The batch stripper is favourable to separate mixtures with a small amount of light components by removing the heavy components as bottom products. In this paper, we are presenting a shortcut procedure based on our earlier work for design and simulation of the inverted batch distillation column, which is equivalent to the Fenske-Underwood-Gilliland procedure for continuous distillation. Given a separation task, we propose to compute the minimum number of stages(Nbmin) and the minimum reboil ratio(Rbmin) required in a batch stripper,which are the stages and reboil ratio required in a hypothetical inverted batch distillation column operating in total reboil ratio or having an infinite number of stages, respectively. Then, it is shown that the performance of inverted batch columns with a finite number of stages and reboil ratios could be correlated in Gilliland coordinates with the minimum stages Nbmin and the minimum reboil ratio Rbmin.
基金the financial support by the National Natural Science Foundation of China (21306036)
文摘Through separation of the hexane-heptane–octane system in a cross-wall adiabatic dividing wall column, the effects of feed position, side-draw position, liquid split ratio, vapor split ratio and their interactions on the energy consumption were analyzed by Aspen Plus under the constant product purity, and the response surface model for the energy consumption was regressed. Based on the restriction on the optimal operating zone, the comparison of different combinations of surrogate models and optimization methods showed that, the combination of the Kriging model and multi-island genetic algorithm(Kriging-MIGA) had better prediction ability than the combination of the response surface model and partial derivative method(RSM-PD), and RSM-PD had better optimization effect than Kriging-MIGA. With a self-made cross-wall adiabatic dividing wall column, the temperature at measuring points and the energy consumption were measured during experiments, the comparison between measured values and simulated ones demonstrated that the optimized values of variables searched by RSM-PD and Kriging-MIGA could be both used as the optimum technological conditions since the experimental reliability was ensured, with the optimum technological conditions shown below: The feed position is 6, the side-draw position is 7, the combinations of liquid split ratio and vapor split ratio are [0.14, 0.5] and [0.16, 0.52], respectively. RSM-PD and Kriging-MIGA can provide the appropriate optimization methods for the dividing wall column.
文摘This paper presents the experimental and numerical studies conducted on a steel column and a steel frame structure using free vibration analysis.The effects of damages on structures were investigated,which were simulated by introducing multiple cracks at different locations in the experimental and numerical models.The acceleration responses of the test models,were recorded through an accelerometer,and were used to calibrate the numerical models developed in finite element based software.Modal frequencies of damaged and undamaged structures were compared and analyzed,to derive relationships for damaged and undamaged structures’frequencies in terms of crack depth.It was found that,due to the presence of cracks,the mechanical properties of a structure changes,whereby,the modal frequencies decrease.An approximately linear trend was observed for the frequency decrease with the increase in crack depth,which was also confirmed by the numerical models.The derived relationships were extended to further develop a mechanics-based damage scale for steel structures,to help facilitate structural health monitoring and screening of vulnerable structures.
基金Project supported by the National Natural Science Foundation of China.
文摘The strategy of expert system for high performance liquid chromatography was discussed, the attentions are mainly placed on the knowledge base for selection of column system, separation modes and detection modes in the analysis of amino acids, peptides and proteins.
基金financial supports from the National Key R&D Program of China(No.2018YFC1801804)the Shandong Provincial Natural Science Foundation,China(Nos.ZR2020QD120 and ZR2018LD001)Project of Introducing and Cultivating Young Talent in the Universities of Shandong Province,China(No.QC2019YY144)。
文摘The column bioleaching of copper flotation tailings was comparatively investigated using layered heap construction method(LM),agglomerate heap construction method(AM),and pellets-sintering heap construction method(PM).The bacterial communities of free,attached,weakly-attached,and strongly-attached microbes in the later bioleaching stage were investigated.In AM group,the addition of lump sulphide ore resulted in the low leachate pH,high ferric iron concentration,and rapid microbial adsorption,which obtained the maximum copper extraction(60.1%)compared with LM(54.6%)and PM(43.9%)groups.The relative abundance of dominant genera and microbial communities of different microbiota underwent changes in three heap construction methods.The alpha-diversity indexes of attached,weakly-attached,and strongly-attached microbes were different,while no significant change was observed in free bacteria.The variation of whole bacterial community was significantly associated with solution pH,total iron,and ferric iron concentrations.Pearson correlation analysis and partial least square path model both indicated that attached bacteria made larger contribution to the copper extraction of tailings.
基金Supported by the National Natural Science Foundation of China.
文摘Overall dispersed side volumetric mass transfer coefficients for protein and amino acids were measured in continuous countercurrent PEG4000/KHP aqueous two-phase systems in a 57mm I.D. packed extraction column. A model for overall dispersed side volumetric mass transfer coefficients was derived by describing the motion of the drops based upon Navier-Stokes equation combined with the relationship between mass transfer coefficients and the drop velocity. The model provides good predictions and can be successfully used in aqueous two-phase extraction. The average relative deviation between calculated values and experimental data ranges from 8% to 14%.
基金the financial support from the National Natural Science Foundation of China(Nos.21676183 and 21978203)。
文摘For N-component distillation(N≥3),consolidation between different column sections is an inevitable manipulation when synthesizing complex distillation configurations.In the consolidation,the idiomatic vapor balance(IVB)rule,in which the larger vapor flowrate in the two columns before consolidation will be chosen as the balanced vapor flowrate at the consolidation point,has been widely used.However,the applicability of the IVB rule has not been verified,which is of essential importance to the accuracy of the distillation configuration synthesis.In the present study,the applicability of the IVB rule to distillation column consolidation was systematically explored by rigorous method for the first time.First,the separation of ideal and non-ideal three-component mixtures with variable compositions was studied,and the optimized configurations before and after consolidation were determined by a rigorous method.The results indicated that for the separation of an ideal mixture,the IVB rule was applicable for the whole composition range,while for the separation of a non-ideal mixture,the IVB rule was only applicable for very limited composition range.Finally,two cases of synthesizing distillation configurations for the separation of non-ideal mixtures were studied to verify the remarkable deviations the IVB rule may cause.The results indicated that the applicability of the shortcut method using the IVB rule to the distillation configuration synthesis depended on the composition of the non-ideal mixture,and a remarkable error might result and the truly optimal configuration might be missed if the IVB rule is applied to a non-ideal mixture.
文摘Methacrylate-based monolithic column was prepared in fused-silica capillary (80 ′ 0.32 mm i.d.) by in situ polymerizetion reaction using glycidyl methacrylate as monomer;ethylene dimethacrylate as crosslinker;1-propanol, 1,4-butanediol, and water as porogenic solvents. The monolith matrix was modified with trimethylamine to create strong anion exchanger via ring opening reaction of epoxy groups. The morphology of the monolithic column was studied by using Scanning Electron Microscope (SEM). This column had good mechanical stability and permeability. The effects of various mobile phases for separation of inorganic anions were investigated. Iodate, bromate, nitrite, bromide, and nitrate were separated within 11 min using100 mMpotassium chloride as mobile phase and detected at 210 nm. This method showed good precision of retention time, acceptable linearity and good sensitivity. Under the optimum condition, the RSD of the retention time was in the range of 1.09%-1.75% (n = 6). The calibration curve showed linear relationships between the peak area and the concentration. The limits of detection (LOD) and the limits of quantitation (LOQ) were between 0.08-0.18 mM and 0.26-0.61 mM, respectively. This method was applied to the determination of inorganic anions in tap water and ground water samples.
文摘For achieving optimized jet grout parameters and W/C ratio it is concluded to set trial tests in constant local soil as the conclusion depends on local soil and presence of the extensive range of the effective parameters. Considering the benefits, due to abundance of the involved variables and the intrinsic geological complexity, this system follows a great expense in the trial and implementation phases. Utilizing the soft computing methods, this paper proposes a new approach to reduce or to eliminate the cost of the trial phase. Therefore, the Adaptive Neuro Fuzzy Inference System (ANFIS) was utilized to study the possibility of anticipating the diameter of the jet grout (Soilcrete) columns on the trial phase based on the Trial and Error procedure. Data were collected from several projects and formed three sets of data. Consequently, parameters were held constant (as input) and the diameters of the Soilcrete columns were recorded (as output). To increase the precision, aforementioned data sets were combined and ten different data sets were created and studied, with all the results being assessed in two different approaches. Accordingly, Gaussian Function results in a huge number of precise and acceptable outcomes among available functions. Based on the measurements, Gaussian Function achieves the values of the R which are frequently more than 0.8 and lower values of the RMSE. Therefore, utilizing Gaussian Function, mainly a congruent relation between the R and RMSE is experienced and it leads to close proximity of the actual and predicted values of the Soilcrete diameter.
文摘This paper presents a comprehensive review of various traditional systems of crude oil distillation column design, modeling, simulation, optimization and control methods. Artificial neural network (ANN), fuzzy logic (FL) and genetic algorithm (GA) framework were chosen as the best methodologies for design, optimization and control of crude oil distillation column. It was discovered that many past researchers used rigorous simulations which led to convergence problems that were time consuming. The use of dynamic mathematical models was also challenging as these models were also time dependent. The proposed methodologies use back-propagation algorithm to replace the convergence problem using error minimal method.
基金Project supported by the National Natural Science Foundation of China
文摘The recommendation of column system (RCS) is the most important component of the expert system of chromatography. The system which we studied and built is a software package based on the theory devdoped for many years. The most fundamental theoretical base is the quantitative relationship between molecular structure parameters and the retention value of the solute:
文摘An object-oriented prototype expert system ORDEES for off-line trouble-shooting of refinery distillation columns is developed. It is found that highly modular knowledge base can be designed, and different types of data (e.g., graphs, numberical data, and algorithms) may be manipulated, by using object-oriented knowledge representation. In addition, a method termed Object-Oriented Multifunction Switcher is proposed for building multifunction expert systems. The results of the study are expected to be useful for designing multifunction expert systems for complex petroleum refining and petro-chemical processes with many kinds of equipment.
文摘Base on industrial research and experience, the process of methanol distillation is analyzed,and above all, a new concept of high pressure flowsheet and low pressure flowsheet is defined. The new configuration helps to handle problems encountered in many factories in China. The inter influence between process and column internal pattern is also pointed out. Recommendation of new column internal designs is given. Finally, industrial examples tell the how the new concept works and the possibility of combining process to give more opens to solve engineering problems.
文摘This research work investigated comparative studies of expert system design and control of crude oil distillation column (CODC) using artificial neural networks based Monte Carlo (ANNBMC) simulation of random processes and artificial neural networks (ANN) model which were validated using experimental data obtained from functioning crude oil distillation column of Port-Harcourt Refinery, Nigeria by MATLAB computer program. Ninety percent (90%) of the experimental data sets were used for training while ten percent (10%) were used for testing the networks. The maximum relative errors between the experimental and calculated data obtained from the output variables of the neural network for CODC design were 1.98 error % and 0.57 error % when ANN only and ANNBMC were used respectively while their respective values for the maximum relative error were 0.346 error % and 0.124 error % when they were used for the controller prediction. Larger number of iteration steps of below 2500 and 5000 were required to achieve convergence of less than 10-7?for the training error using ANNBMC for both the design of the CODC and controller respectively while less than 400 and 700 iteration steps were needed to achieve convergence of 10-4?using ANN only. The linear regression analysis performed revealed the minimum and maximum prediction accuracies to be 80.65% and 98.79%;and 98.38% and 99.98% when ANN and ANNBMC were used for the CODC design respectively. Also, the minimum and maximum prediction accuracies were 92.83% and 99.34%;and 98.89% and 99.71% when ANN and ANNBMC were used for the CODC controller respectively as both methodologies have excellent predictions. Hence, artificial neural networks based Monte Carlo simulation is an effective and better tool for the design and control of crude oil distillation column.
文摘This paper presents the design of a robust control system for a high-purity distillation column. It is concerned with the design of a two degree-of-freedom (2DOF) product-composition controller for a high-purity distillation column. The H<sub>∞</sub> optimization problem is set up to ensure a guaranteed level of robust stability, robust disturbance attenuation and robust reference tracking performance.
基金the National Natural Science Foundation of China(Nos.42176188,42176192)the Hainan Provincial Natural Science Foundation of China(No.421CXTD442)+2 种基金the Stable Supporting Fund of Acoustic Science and Technology Laboratory(No.JCKYS2024604SSJS007)the Fundamental Research Funds for the Central Universities(No.3072024CFJ0504)the Harbin Engineering University Doctoral Research and Innovation Fund(No.XK2050021034)。
文摘In the task of inspecting underwater suspended pipelines,multi-beam sonar(MBS)can provide two-dimensional water column images(WCIs).However,systematic interferences(e.g.,sidelobe effects)may induce misdetection in WCIs.To address this issue and improve the accuracy of detection,we developed a density-based clustering method for three-dimensional water column point clouds.During the processing of WCIs,sidelobe effects are mitigated using a bilateral filter and brightness transformation.The cross-sectional point cloud of the pipeline is then extracted by using the Canny operator.In the detection phase,the target is identified by using density-based spatial clustering of applications with noise(DBSCAN).However,the selection of appropriate DBSCAN parameters is obscured by the uneven distribution of the water column point cloud.To overcome this,we propose an improved DBSCAN based on a parameter interval estimation method(PIE-DBSCAN).First,kernel density estimation(KDE)is used to determine the candidate interval of parameters,after which the exact cluster number is determined via density peak clustering(DPC).Finally,the optimal parameters are selected by comparing the mean silhouette coefficients.To validate the performance of PIE-DBSCAN,we collected water column point clouds from an anechoic tank and the South China Sea.PIE-DBSCAN successfully detected both the target points of the suspended pipeline and non-target points on the seafloor surface.Compared to the K-Means and Mean-Shift algorithms,PIE-DBSCAN demonstrates superior clustering performance and shows feasibility in practical applications.
基金Natural Science Foundation of Sichuan Province under Grant Nos.2022NSFSC0319 and 2022NSFSC0095the Science and Technology Research Projects of Mianyang,China under Grant No.15S-02-3。
文摘The behavior of reinforced concrete(RC)square columns strengthened with self-compacting concrete(SCC)-filled steel tubes under cyclic loading was experimentally investigated.Tests were carried out on eleven reinforced columns and one unreinforced column.The parameters studied for the strengthened columns included axial compression ratio,reinforcement rate,defect rate,strength of SCC,and the section form of a reinforced steel tube.The results show that the steel tube SCC reinforcement method can effectively strengthen RC columns,exert the restraint effect of steel tube,and delay the development of internal concrete cracks.The method can also significantly improve the bearing capacity of RC columns.Regarding ductility,the improvement of the reinforced column is obvious,the deformation resistance of the specimen is enhanced,and the degradation of stiffness and strength is relatively slow,indicating that it has good seismic performance.
