In this work, property clustering techniques and group contribution methods are combined to enable simultaneous consideration of process performance requirements and molecular property constraints. Using this methodol...In this work, property clustering techniques and group contribution methods are combined to enable simultaneous consideration of process performance requirements and molecular property constraints. Using this methodology, the process design problem is solved to identify the property targets corresponding to the desired process performance. A significant advantage of the developed methodology is that for problems that can be satisfactorily described by only three properties, the process and molecular design problems can be simultaneously solved visually on a ternary diagram, irrespective of how many molecular fragments are included in the search space. On the ternary cluster diagram, the target properties are represented as individual points if given as discrete values or as a region if given as intervals. The structure and identity of candidate components is then identified by combining or "mixing" molecular fragments until the resulting properties match the targets.展开更多
This paper discussed an extended model for flexibility analysis of chemical process. Under uncertainty, probability density function is used to describe uncertain parameters instead of hyper-rectangle, and chanceconst...This paper discussed an extended model for flexibility analysis of chemical process. Under uncertainty, probability density function is used to describe uncertain parameters instead of hyper-rectangle, and chanceconstrained programming is a feasible way to deal with the violation of constraints. Because the feasible region of control variables would change along with uncertain parameters, its smallest acceptable size threshold is presented to ensure the controllability condition. By synthesizing the considerations mentioned above, a modified model can describe the flexibility analysis problem more exactly. Then a hybrid algorithm, which integrates stochastic simulation and genetic algorithm, is applied to solve this model and maximize the flexibility region. Both numerical and chemical process examples are presented to demonstrate the effectiveness of the method.展开更多
In the view of the problems existing in horizontal well,such as sand depositing and cleaning difficulty of borehole,a technology with rotating jet suitable to resolution of the problems was presented.Based on liquid s...In the view of the problems existing in horizontal well,such as sand depositing and cleaning difficulty of borehole,a technology with rotating jet suitable to resolution of the problems was presented.Based on liquid solid two-phase flow theory,the analyses on the sand movement law and the swirling field influential factors were conducted.Results show that:1) With the increasing of displacement in horizontal section annulus,swirling field strength increases,and when the displacement is constant,the closer from the nozzle,the stronger the swirling field strength is;2) Head rotating speed and liquid viscosity have little influence on the swirling field strength,but the sand-carrying rate of fluid can increase by increasing liquid viscosity in a certain range;3) Rotating the string and reducing its eccentricity in annulus are conducive for sand migration in the annulus;4) The sand can be suspended and accelerated again and the swirling field strength is enhanced by the helix agitator.Hence,the research results provide the theoretical basis for the design and application of rotating jet tool.展开更多
An extended algorithm of flexibility analysis with a local adjusting method for flexibility region of chemical processes, which is based on the active constraint strategy, is proposed, which fully exploits the flexibi...An extended algorithm of flexibility analysis with a local adjusting method for flexibility region of chemical processes, which is based on the active constraint strategy, is proposed, which fully exploits the flexibility region of the process system operation. The hyperrectangular flexibility region determined by the extended algorithm is larger than that calculated by the previous algorithms. The limitation of the proposed algorithm due to imperfect convexity and its corresponding verification measure are also discussed. Both numerical and actual chemical process examples are presented to demonstrate the effectiveness of the new algorithm.展开更多
Owing to the importance of process intensification in the natural gas associated processes, the present contribution aims to investigate the production of an important natural gas downstream product in an improved sys...Owing to the importance of process intensification in the natural gas associated processes, the present contribution aims to investigate the production of an important natural gas downstream product in an improved system.Accordingly, a membrane-assisted reactor for the oxidative dehydrogenation of ethane is presented. The presented system includes a membrane for axial oxygen dosing into the reaction side. Such a strategy would lead to optimum oxygen distribution along the reactor length and prevention of hot spot formation as well. A feasibility study is conducted by developing a validated mathematical model composed of mass and energy balance equations. The effects of various operating variables are investigated by a rigorous sensitivity analysis.Then, by applying the genetic algorithm, a multi-objective optimization procedure is implemented to obtain the optimum operating condition. Considerable increase in the ethane conversion and ethylene yield are the advancements of membrane-assisted oxidative dehydrogenation reactor working under the optimum condition.More than 30% increase in the ethane conversion is obtained. Furthermore, the ethylene yield is enhanced up to 0.45.展开更多
Gut microorganisms play an important role in the digestion of their host animals. The purpose of this research was to isolate and assess the enzyme-producing microbes from the Apostichopusjaponicus gut. Thirty-nine st...Gut microorganisms play an important role in the digestion of their host animals. The purpose of this research was to isolate and assess the enzyme-producing microbes from the Apostichopusjaponicus gut. Thirty-nine strains that can produce at least one of the three digestive enzymes (protease, amylase, and cellulase) were qualitatively screened based on their extracellular enzyme-producing abilities. The enzyme-producing strains clustered into eight groups at the genetic similarity level of 100% by analyzing the restriction patterns of 16S rDNA amplified with Mbo L Phylogenetic analysis revealed that 37 strains belonged to the genus Bacillus and two were members of the genus Virgibacillus. Enzyme-producing capability results indicate that the main enzyme-producing microflora in the A.japonicus gut was Bacillus, which can produce protease, amylase, and cellulase. Virgibacillus, however, can only produce protease. The high enzyme-producing capability of the isolates suggests that the gut microbiota play an important role in the sea cucumber digestive process.展开更多
Cooling-solidification of sprayed droplets is one of major methods for prilling of melt.Traditionally, this is carried out in an empty tower,and the equipment requirement for producing larger particles is very high,re...Cooling-solidification of sprayed droplets is one of major methods for prilling of melt.Traditionally, this is carried out in an empty tower,and the equipment requirement for producing larger particles is very high,resulting in not only significant cost increasing but also difficulties in transporting melt etc.Based on analysis and simulation,a new prilling process is developed for the melt prilling,which combines a tower with a fluidized bed so that the height of equipment is greatly decreased,and it exhibits satisfactory performance in industrial application. Mathematical model for tower prilling,its simulated results,the structure of the equipment for the innovated prilling process and its application are addressed.展开更多
During underground coal gasification (UCG), whereby coal is converted to syngas in situ, a cavity is formed in the coal seam. The cavity growth rate (CGR) or the moving rate of the gasification face is affected by...During underground coal gasification (UCG), whereby coal is converted to syngas in situ, a cavity is formed in the coal seam. The cavity growth rate (CGR) or the moving rate of the gasification face is affected by controllable (operation pressure, gasification time, geometry of UCG panel) and uncontrollable (coal seam properties) factors. The CGR is usually predicted by mathematical models and laboratory experiments, which are time consuming, cumbersome and expensive. In this paper, a new simple model for CGR is developed using non-linear regression analysis, based on data from 1 l UCG field trials. The empirical model compares satisfactorily with Perkins model and can reliably predict CGR.展开更多
This paper sets out the preliminary results of an experimental research plan aimed at analysing the thermal processes inherent to the urbanisation effect. Although this effect is undeniable, the extent of its impact i...This paper sets out the preliminary results of an experimental research plan aimed at analysing the thermal processes inherent to the urbanisation effect. Although this effect is undeniable, the extent of its impact is a matter of controversy. The results obtained in this study show both the nature of the phenomenon and its considerable magnitude. Failure to take this process into account might seriously bias any analysis of thermal evolution, the cornerstone of the climate change hypothesis.展开更多
Fault degradation prognostic, which estimates the time before a failure occurs and process breakdowns, has been recognized as a key component in maintenance strategies nowadays. Fault degradation processes are, in gen...Fault degradation prognostic, which estimates the time before a failure occurs and process breakdowns, has been recognized as a key component in maintenance strategies nowadays. Fault degradation processes are, in general,slowly varying and can be modeled by autoregressive models. However, industrial processes always show typical nonstationary nature, which may bring two challenges: how to capture fault degradation information and how to model nonstationary processes. To address the critical issues, a novel fault degradation modeling and online fault prognostic strategy is developed in this paper. First, a fault degradation-oriented slow feature analysis(FDSFA) algorithm is proposed to extract fault degradation directions along which candidate fault degradation features are extracted. The trend ability assessment is then applied to select major fault degradation features. Second, a key fault degradation factor(KFDF) is calculated to characterize the fault degradation tendency by combining major fault degradation features and their stability weighting factors. After that, a time-varying regression model with temporal smoothness regularization is established considering nonstationary characteristics. On the basis of updating strategy, an online fault prognostic model is further developed by analyzing and modeling the prediction errors. The performance of the proposed method is illustrated with a real industrial process.展开更多
One of the bottle-neck problems to the commercial development of supercritlcal water oxidation (SCWO) is high operation cost. In this study the condition to realize an energetically self-sufficient SCWO process is a...One of the bottle-neck problems to the commercial development of supercritlcal water oxidation (SCWO) is high operation cost. In this study the condition to realize an energetically self-sufficient SCWO process is analyzed. The reaction heat is recovered by means of Organic Rankine Circle. The process of SCWO for phenol is simulated with the Aspen Plus~ process simulator, and the results show that the influence of temperature on reaction heat is small at a constant pressure. It is reasonable to neglect the effect of temperature and to estimate the heat of reaction with average temperature when the temperature changes in a small range. The necessary condition to realize an energetically self-sufficient SCWO process is that the released energy is not less than consumed one. Whether a waste system with given chemical composition is energeticallyself-sufficient can be estimated by ^QR^QH 〉 W The thermodynamics analysis shows that energetically self-sufficient SCWO process with an Organic Rankine Cycle is a feasible technology for the recovery of SCWO reaction heat,and the energy balance point for phenol is 2wt%.展开更多
The exact shape and size of the gasification channel during underground coal gasification(UGC) are of vital importance for the safety and stability of the upper parts of the geological formation.In practice existing g...The exact shape and size of the gasification channel during underground coal gasification(UGC) are of vital importance for the safety and stability of the upper parts of the geological formation.In practice existing geological measurements are insufficient to obtain such information because the coal seam is typically deeply buried and the geological conditions are often complex.This paper introduces a cylindrical model for the gasification channel.The rock and soil masses are assumed to be homogeneous and isotropic and the effect of seepage on the temperature field was neglected.The theory of heat conduction was used to write the equation predicting the temperature field around the gasification channel.The idea of an excess temperature was introduced to solve the equations.Applying this model to UCG in the field for an influence radius,r,of 70 m gave the model parameters,u1,2,3...,of 2.4,5.5,8.7...By adjusting the radius(2,4,or 6 m) reasonable temperatures of the gasification channel were found for 4 m.The temperature distribution in the vertical direction,and the combustion volume,were also calculated.Comparison to field measurements shows that the results obtained from the proposed model are very close to practice.展开更多
Discharges and emissions in the coal mining process have a strong effect both on the environment and on human health. This problem is usually be a negative one and has only been recognized qualitatively, due to the la...Discharges and emissions in the coal mining process have a strong effect both on the environment and on human health. This problem is usually be a negative one and has only been recognized qualitatively, due to the lack of effective quantitative methods. Based on emergy theory and accounting methodology, a set of quantitative methods for accounting the environmental support due to pollutants emissions was first introduced. Then impacts on environment and effects on human health were quantified using the unified units. The results indicated that water pollutants caused more impacts on the environment than air pollutants did, i.e., more environmental contributions are needed to dilute and absorb water pollutants. The occupation of land caused by coal mining gangue waste stacking has led to a huge loss of environmental services over the years. Moreover, the potential damage on the human condition health caused by CO2 through climate change cannot be ignored. Finally, the impacts of mining activities on environmental and human health in unified units are shown to provide a quantitative insight into the disadvantage of coal mining. The comparable results of the method indicate the different influence of various pollutants and the contribution of 'natural capital' directly. This work is a part of ongoing thermodynamic input-output analysis and life cycle analysis of coal mining systems (which are in process.)展开更多
A new superstructure model of heat exchanger networks (HEN) with streamsplits based on rangers of streams supply temperatures and heat capacity flow rates is presented.The simultaneous optimal mathematical model of fl...A new superstructure model of heat exchanger networks (HEN) with streamsplits based on rangers of streams supply temperatures and heat capacity flow rates is presented.The simultaneous optimal mathematical model of flexible HEN synthesis is established too. Firstly,the streams with rangers of supply temperatures and/or the streams with the rangers of heat capacityflow rates are pretreated; Secondly, several rules are proposed to establish the superstructuremodel of HEN with splits and the simultaneous optimal mathematical model of flexible HEN; Thirdly,the improving genetic algorithm is applied to solve the mathematical model established at the secondstep effectively, and the original optimal structure of HEN based on the maximum operation limitingcondition can be obtained easily; Finally, the rules of heat exchange unit merged and the heat loadof heat exchanger relaxed are presented, the flexible configuration of HEN satisfied the operationcondition between the upper and down bounds of supply temperature and heat capacity flow rates canbe obtained based on the original optimal structure of HEN by means of these rules. A case studydemonstrates the method presented in this paper is effective展开更多
Objective: We aimed to examine the expression of cyclooxygenase-2 and the relationship with the pathological types, TNM stage, lymph node metastasis, the degree of differentiation, smoking and the survival. Methods: I...Objective: We aimed to examine the expression of cyclooxygenase-2 and the relationship with the pathological types, TNM stage, lymph node metastasis, the degree of differentiation, smoking and the survival. Methods: Immunohistochemical staining method was used to examine the expression of cyclooxygenase-2 of 121 cases of lung cancer and three control groups. The data were statistically analyzed. Results: Compared with the health group, cyclooxygenase-2 was over expressed in the inflammatory tissue(P = 0.036), lung adenocarcinoma(P = 0.005) and squamous carcinoma(P = 0.047). Compared with patients without lymph node metastasis, cyclooxygenase-2 was over expressed(P = 0.033) in patients with lymph node metastasis. Compared with high differentiation group, cyclooxygenase-2 was over expressed(P = 0.004) in low differentiation group. Compared with non-smokers, the expression of cyclooxygenase-2 increased in smokers(P = 0.000). The median survival time of patients that the expression of cyclooxygenase-2 were negative was 9 months(95% CI, 5.6–12.4 months). The median survival time of patients that the expression of cyclooxygenase-2 were positive was 5 months(95% CI, 3–7 months). They was statistical difference(P = 0.001). Conclusion: Overexpression of cyclooxygenase-2 is associated with pathological types, TNM stage, lymph node metastasis, degrees of differentiation, smoking and prognosis in lung cancer.展开更多
基金the US NSF CAREER Program (CTS-0546925)in part through a travel grant (0647113)
文摘In this work, property clustering techniques and group contribution methods are combined to enable simultaneous consideration of process performance requirements and molecular property constraints. Using this methodology, the process design problem is solved to identify the property targets corresponding to the desired process performance. A significant advantage of the developed methodology is that for problems that can be satisfactorily described by only three properties, the process and molecular design problems can be simultaneously solved visually on a ternary diagram, irrespective of how many molecular fragments are included in the search space. On the ternary cluster diagram, the target properties are represented as individual points if given as discrete values or as a region if given as intervals. The structure and identity of candidate components is then identified by combining or "mixing" molecular fragments until the resulting properties match the targets.
文摘This paper discussed an extended model for flexibility analysis of chemical process. Under uncertainty, probability density function is used to describe uncertain parameters instead of hyper-rectangle, and chanceconstrained programming is a feasible way to deal with the violation of constraints. Because the feasible region of control variables would change along with uncertain parameters, its smallest acceptable size threshold is presented to ensure the controllability condition. By synthesizing the considerations mentioned above, a modified model can describe the flexibility analysis problem more exactly. Then a hybrid algorithm, which integrates stochastic simulation and genetic algorithm, is applied to solve this model and maximize the flexibility region. Both numerical and chemical process examples are presented to demonstrate the effectiveness of the method.
基金Projects(51004082,51222406)supported by the National Natural Science Foundation of ChinaProject(NCET-12-1061)supported by the New Century Excellent Talents in University of ChinaProjects(12TD007,2011JQ0020)supported by Scientific Research Innovation Team Project of Sichuan and the Sichuan Youth Sci-tech Fund,China
文摘In the view of the problems existing in horizontal well,such as sand depositing and cleaning difficulty of borehole,a technology with rotating jet suitable to resolution of the problems was presented.Based on liquid solid two-phase flow theory,the analyses on the sand movement law and the swirling field influential factors were conducted.Results show that:1) With the increasing of displacement in horizontal section annulus,swirling field strength increases,and when the displacement is constant,the closer from the nozzle,the stronger the swirling field strength is;2) Head rotating speed and liquid viscosity have little influence on the swirling field strength,but the sand-carrying rate of fluid can increase by increasing liquid viscosity in a certain range;3) Rotating the string and reducing its eccentricity in annulus are conducive for sand migration in the annulus;4) The sand can be suspended and accelerated again and the swirling field strength is enhanced by the helix agitator.Hence,the research results provide the theoretical basis for the design and application of rotating jet tool.
文摘An extended algorithm of flexibility analysis with a local adjusting method for flexibility region of chemical processes, which is based on the active constraint strategy, is proposed, which fully exploits the flexibility region of the process system operation. The hyperrectangular flexibility region determined by the extended algorithm is larger than that calculated by the previous algorithms. The limitation of the proposed algorithm due to imperfect convexity and its corresponding verification measure are also discussed. Both numerical and actual chemical process examples are presented to demonstrate the effectiveness of the new algorithm.
文摘Owing to the importance of process intensification in the natural gas associated processes, the present contribution aims to investigate the production of an important natural gas downstream product in an improved system.Accordingly, a membrane-assisted reactor for the oxidative dehydrogenation of ethane is presented. The presented system includes a membrane for axial oxygen dosing into the reaction side. Such a strategy would lead to optimum oxygen distribution along the reactor length and prevention of hot spot formation as well. A feasibility study is conducted by developing a validated mathematical model composed of mass and energy balance equations. The effects of various operating variables are investigated by a rigorous sensitivity analysis.Then, by applying the genetic algorithm, a multi-objective optimization procedure is implemented to obtain the optimum operating condition. Considerable increase in the ethane conversion and ethylene yield are the advancements of membrane-assisted oxidative dehydrogenation reactor working under the optimum condition.More than 30% increase in the ethane conversion is obtained. Furthermore, the ethylene yield is enhanced up to 0.45.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA10A412)the National Natural Science Foundation of China(No.41106145)+2 种基金the National Key Technology R&D Program of China(No.2011BAD13B02)the Science and Technology Development Planning Project of Shandong Province(No.2012GGA06021)the Key Laboratory of Mariculture&Stock Enhancement in North China’s Sea,Ministry of Agriculture,China(No.2014-MSENC-KF-03)
文摘Gut microorganisms play an important role in the digestion of their host animals. The purpose of this research was to isolate and assess the enzyme-producing microbes from the Apostichopusjaponicus gut. Thirty-nine strains that can produce at least one of the three digestive enzymes (protease, amylase, and cellulase) were qualitatively screened based on their extracellular enzyme-producing abilities. The enzyme-producing strains clustered into eight groups at the genetic similarity level of 100% by analyzing the restriction patterns of 16S rDNA amplified with Mbo L Phylogenetic analysis revealed that 37 strains belonged to the genus Bacillus and two were members of the genus Virgibacillus. Enzyme-producing capability results indicate that the main enzyme-producing microflora in the A.japonicus gut was Bacillus, which can produce protease, amylase, and cellulase. Virgibacillus, however, can only produce protease. The high enzyme-producing capability of the isolates suggests that the gut microbiota play an important role in the sea cucumber digestive process.
文摘Cooling-solidification of sprayed droplets is one of major methods for prilling of melt.Traditionally, this is carried out in an empty tower,and the equipment requirement for producing larger particles is very high,resulting in not only significant cost increasing but also difficulties in transporting melt etc.Based on analysis and simulation,a new prilling process is developed for the melt prilling,which combines a tower with a fluidized bed so that the height of equipment is greatly decreased,and it exhibits satisfactory performance in industrial application. Mathematical model for tower prilling,its simulated results,the structure of the equipment for the innovated prilling process and its application are addressed.
文摘During underground coal gasification (UCG), whereby coal is converted to syngas in situ, a cavity is formed in the coal seam. The cavity growth rate (CGR) or the moving rate of the gasification face is affected by controllable (operation pressure, gasification time, geometry of UCG panel) and uncontrollable (coal seam properties) factors. The CGR is usually predicted by mathematical models and laboratory experiments, which are time consuming, cumbersome and expensive. In this paper, a new simple model for CGR is developed using non-linear regression analysis, based on data from 1 l UCG field trials. The empirical model compares satisfactorily with Perkins model and can reliably predict CGR.
文摘This paper sets out the preliminary results of an experimental research plan aimed at analysing the thermal processes inherent to the urbanisation effect. Although this effect is undeniable, the extent of its impact is a matter of controversy. The results obtained in this study show both the nature of the phenomenon and its considerable magnitude. Failure to take this process into account might seriously bias any analysis of thermal evolution, the cornerstone of the climate change hypothesis.
基金Project(U1709211) supported by NSFC-Zhejiang Joint Fund for the Integration of Industrialization and Informatization,ChinaProject(ICT2021A15) supported by the State Key Laboratory of Industrial Control Technology,Zhejiang University,ChinaProject(TPL2019C03) supported by Open Fund of Science and Technology on Thermal Energy and Power Laboratory,China。
文摘Fault degradation prognostic, which estimates the time before a failure occurs and process breakdowns, has been recognized as a key component in maintenance strategies nowadays. Fault degradation processes are, in general,slowly varying and can be modeled by autoregressive models. However, industrial processes always show typical nonstationary nature, which may bring two challenges: how to capture fault degradation information and how to model nonstationary processes. To address the critical issues, a novel fault degradation modeling and online fault prognostic strategy is developed in this paper. First, a fault degradation-oriented slow feature analysis(FDSFA) algorithm is proposed to extract fault degradation directions along which candidate fault degradation features are extracted. The trend ability assessment is then applied to select major fault degradation features. Second, a key fault degradation factor(KFDF) is calculated to characterize the fault degradation tendency by combining major fault degradation features and their stability weighting factors. After that, a time-varying regression model with temporal smoothness regularization is established considering nonstationary characteristics. On the basis of updating strategy, an online fault prognostic model is further developed by analyzing and modeling the prediction errors. The performance of the proposed method is illustrated with a real industrial process.
文摘One of the bottle-neck problems to the commercial development of supercritlcal water oxidation (SCWO) is high operation cost. In this study the condition to realize an energetically self-sufficient SCWO process is analyzed. The reaction heat is recovered by means of Organic Rankine Circle. The process of SCWO for phenol is simulated with the Aspen Plus~ process simulator, and the results show that the influence of temperature on reaction heat is small at a constant pressure. It is reasonable to neglect the effect of temperature and to estimate the heat of reaction with average temperature when the temperature changes in a small range. The necessary condition to realize an energetically self-sufficient SCWO process is that the released energy is not less than consumed one. Whether a waste system with given chemical composition is energeticallyself-sufficient can be estimated by ^QR^QH 〉 W The thermodynamics analysis shows that energetically self-sufficient SCWO process with an Organic Rankine Cycle is a feasible technology for the recovery of SCWO reaction heat,and the energy balance point for phenol is 2wt%.
基金supported by a grant from the Major State Basic Research and Development Program of China (No. 2007CB714102)sponsored by the Fundamental Research Funds for the Central Universities (No. 2009B00714)
文摘The exact shape and size of the gasification channel during underground coal gasification(UGC) are of vital importance for the safety and stability of the upper parts of the geological formation.In practice existing geological measurements are insufficient to obtain such information because the coal seam is typically deeply buried and the geological conditions are often complex.This paper introduces a cylindrical model for the gasification channel.The rock and soil masses are assumed to be homogeneous and isotropic and the effect of seepage on the temperature field was neglected.The theory of heat conduction was used to write the equation predicting the temperature field around the gasification channel.The idea of an excess temperature was introduced to solve the equations.Applying this model to UCG in the field for an influence radius,r,of 70 m gave the model parameters,u1,2,3...,of 2.4,5.5,8.7...By adjusting the radius(2,4,or 6 m) reasonable temperatures of the gasification channel were found for 4 m.The temperature distribution in the vertical direction,and the combustion volume,were also calculated.Comparison to field measurements shows that the results obtained from the proposed model are very close to practice.
基金Supported by the National Natural Science Foundation of China (41101560)
文摘Discharges and emissions in the coal mining process have a strong effect both on the environment and on human health. This problem is usually be a negative one and has only been recognized qualitatively, due to the lack of effective quantitative methods. Based on emergy theory and accounting methodology, a set of quantitative methods for accounting the environmental support due to pollutants emissions was first introduced. Then impacts on environment and effects on human health were quantified using the unified units. The results indicated that water pollutants caused more impacts on the environment than air pollutants did, i.e., more environmental contributions are needed to dilute and absorb water pollutants. The occupation of land caused by coal mining gangue waste stacking has led to a huge loss of environmental services over the years. Moreover, the potential damage on the human condition health caused by CO2 through climate change cannot be ignored. Finally, the impacts of mining activities on environmental and human health in unified units are shown to provide a quantitative insight into the disadvantage of coal mining. The comparable results of the method indicate the different influence of various pollutants and the contribution of 'natural capital' directly. This work is a part of ongoing thermodynamic input-output analysis and life cycle analysis of coal mining systems (which are in process.)
基金Supported by the State Major Basic Research Department Program of China (No. G20000263) and the Deutsche Forschungs- gemeinschaft(DFG)(No. RO294/9).
文摘A new superstructure model of heat exchanger networks (HEN) with streamsplits based on rangers of streams supply temperatures and heat capacity flow rates is presented.The simultaneous optimal mathematical model of flexible HEN synthesis is established too. Firstly,the streams with rangers of supply temperatures and/or the streams with the rangers of heat capacityflow rates are pretreated; Secondly, several rules are proposed to establish the superstructuremodel of HEN with splits and the simultaneous optimal mathematical model of flexible HEN; Thirdly,the improving genetic algorithm is applied to solve the mathematical model established at the secondstep effectively, and the original optimal structure of HEN based on the maximum operation limitingcondition can be obtained easily; Finally, the rules of heat exchange unit merged and the heat loadof heat exchanger relaxed are presented, the flexible configuration of HEN satisfied the operationcondition between the upper and down bounds of supply temperature and heat capacity flow rates canbe obtained based on the original optimal structure of HEN by means of these rules. A case studydemonstrates the method presented in this paper is effective
文摘Objective: We aimed to examine the expression of cyclooxygenase-2 and the relationship with the pathological types, TNM stage, lymph node metastasis, the degree of differentiation, smoking and the survival. Methods: Immunohistochemical staining method was used to examine the expression of cyclooxygenase-2 of 121 cases of lung cancer and three control groups. The data were statistically analyzed. Results: Compared with the health group, cyclooxygenase-2 was over expressed in the inflammatory tissue(P = 0.036), lung adenocarcinoma(P = 0.005) and squamous carcinoma(P = 0.047). Compared with patients without lymph node metastasis, cyclooxygenase-2 was over expressed(P = 0.033) in patients with lymph node metastasis. Compared with high differentiation group, cyclooxygenase-2 was over expressed(P = 0.004) in low differentiation group. Compared with non-smokers, the expression of cyclooxygenase-2 increased in smokers(P = 0.000). The median survival time of patients that the expression of cyclooxygenase-2 were negative was 9 months(95% CI, 5.6–12.4 months). The median survival time of patients that the expression of cyclooxygenase-2 were positive was 5 months(95% CI, 3–7 months). They was statistical difference(P = 0.001). Conclusion: Overexpression of cyclooxygenase-2 is associated with pathological types, TNM stage, lymph node metastasis, degrees of differentiation, smoking and prognosis in lung cancer.