The“tailing”effect caused by residual non-aqueous phase liquids(NAPLs)in porous aquifers is one of the frontiers in pollution hydrogeology research.Based on the current knowledge that the residual NAPLs is mainly co...The“tailing”effect caused by residual non-aqueous phase liquids(NAPLs)in porous aquifers is one of the frontiers in pollution hydrogeology research.Based on the current knowledge that the residual NAPLs is mainly controlled by the pore structure of soil,this study established a method for evaluating the residual saturation of NAPLs by investigating the fractal dimension of porous media.In this study,the soil column experiments of residual light NAPLs(LNAPLs)in sandy aquifer with different ratios of sands and soil were carried out,and the correlation between the fractal dimension of the medium,the residual of LNAPLs and the soil structure parameters are statistically analyzed,and its formation mechanism and main control factors are discussed.The results show that:Under our experimental condition:(1)the fractal dimension of the medium has a positive correlation with the residual saturation of NAPLs generally,and the optimal fitting function can be described by a quadratic model:S_(R)=192.02 D2-890.73 D+1040.8;(2)the dominant formation mechanism is:Smaller pores in the medium is related to larger fractal dimension,which leads to higher residual saturation of NAPLs;stronger heterogeneity of the medium is related to larger fractal dimension,which also leads to higher residual saturation of NAPLs;(3)the micro capillary pores characterized by fine sand are the main controlling factors of the formation mechanism.It is concluded that both the theory and the method of using fractal dimension of the medium to evaluate the residual saturation of NAPLs are feasible.This study provides a new perspective for the research of“tailing”effect of NAPLs in porous media aquifer.展开更多
Non aqueous phase liquids (NAPLs) pollution are worldwide problems at present. NAPLs which enter the underground through spills or leaks may cause long lasting soil and groundwater contamination problems. Groundwater ...Non aqueous phase liquids (NAPLs) pollution are worldwide problems at present. NAPLs which enter the underground through spills or leaks may cause long lasting soil and groundwater contamination problems. Groundwater can be contaminated by non aqueous phase contaminants that are less dense (LNAPL) or denser (DNAPL) than water. The movement of both types of NAPLs will be influenced by the hydrogeological conditions, such as groundwater level, hydraulic conductivity, and porosity etc., however, LNAPL pollutants tend to concentrate at the water table while DNAPL may migrate further down. Understanding the underground migration mechanisms of NAPLs is of primary importance in pollution prediction and site remediation. Several laboratory simulations for NAPLs’ underground movements in porous media have been done in the past (A.S.Abdul et al., 1988, 1989; C.Tang et al., 1995). In this paper, we try to use STOMP (Subsurface Transport Over Multiple Phases) code to simulate the underground migration of NAPLs. The main purposes are: (1). to understand NAPLs’ underground migration mechanisms; (2). to analyze the sensitivities of model parameters, such as hydraulic conductivity, porosity, etc., and to know what are the most sensitive and important parameters in the model application; and (3). to study NAPLs movements in different hydrogeological conditions. The simulations include: Through the computer simulation, we have found that hydraulic conductivity and porosity are very sensitive in the model simulation, small changes of these parameters will cause big difference of the results, therefore, it is essential to accurately determine these parameters for high quality model simulation; The movements of NAPLs in different geological formation are quite different, two different geological media ( clayey sand and sand ) have been chosen in this paper to simulate NAPLs movement with different combinations ( i.e., moving from clayey sand to sand, and from sand to clayey sand ), the results have been analyzed and discussed; Finally, the influence of groundwater level variation to NAPLs (LNAPL and DNAPL) movement has been simulated by using pumping and injecting wells in the model. The results are compared with laboratory simulations conducted by C.Tang et al.. These results may helpful to understand the behavior of NAPLs during the remediation, such as pumping and treat, and air sparging. It is also important to the design of the remediation plans.展开更多
The purpose of this study is to shed light on the southern part of Italy where Catalonians ruled. Great numbers of Spaniards, principally the Catalonians, headed to that country. This affected the language, and, in tu...The purpose of this study is to shed light on the southern part of Italy where Catalonians ruled. Great numbers of Spaniards, principally the Catalonians, headed to that country. This affected the language, and, in turn, the history of people＇s last names. At first, some of the Spanish last names were used as nicknames for Italians. The method 1 used to get the data from primary sources was from spending time in Italy for four consecutive summers and visiting towns in the Naples area while I collected surnames found on houses. The Catalonians came to rule Sardinia, and their language and subsequently Spanish were official on the island. The linguistic influence of Spanish does not stop with surnames. A list of Spanish and Basque surnames which is redolent of the history of southern Italy and Sicily is appended. The geolinguistics interest lies in the way that the study of language, both ordinary words and proper nouns, offers important clues to the lives and movements of people of ages past, reflects political and economic aspects and also explains the ethnic origin of people who live in Sicily and Italy today or are descendants of Italians who have been important immigrants in the Americas, in Australia, and indeed around the world.展开更多
In this paper, we are interested by the dissolution of NAPL (Non-Aqueous Phase Liquid) contaminants in heterogeneous soils or aquifers. The volume averaging technique is applied to 2D systems with Darcy-scale heteroge...In this paper, we are interested by the dissolution of NAPL (Non-Aqueous Phase Liquid) contaminants in heterogeneous soils or aquifers. The volume averaging technique is applied to 2D systems with Darcy-scale heterogeneities. A large-scale model is derived from a Darcy-scale dissolution model in the case of small and large Damkholer numbers, i.e., for smooth or sharp dissolution fronts. The resulting models in both cases have the mathematical structure of a non-equilibrium dissolution model. It is shown how to calculate the resulting mass exchange and relative permeability terms from the Darcy-scale heterogeneities and other fluid properties. One of the important finding is that the obtained values have a very different behavior compared to the Darcy-scale usual correlations. The large scale correlations are also very different between the two limit cases. The resulting large-scale models are compared favorably to Darcy-scale direct simulations.展开更多
Through an analysis of the accounts of English travellers in Naples between 1816 and 1841, the objective of this paper is to attempt to identify an image of the city and its inhabitants without following the direction...Through an analysis of the accounts of English travellers in Naples between 1816 and 1841, the objective of this paper is to attempt to identify an image of the city and its inhabitants without following the direction of the usual negative stereotypes common to much of the literature associated with the ＂Grand Tourist＂, a literature to which scholars and readers from the 16th to the 19th century were used. The research also aims to demonstrate through previously unknown and unheeded sources that there were not only those English travellers on their Grand Tour of the post-Restoration Bourbon Mezzogiorno （southern Italy） looking for an opportunity of comparing their own civilization （which was considered far superior） to a more fragile reality. There were also other British people who had identified, with a critical eye and spirit of observation, the existence of a Naples and a south Italy which did not merely represent the sum of stereotypes and fallacies handed down through the centuries, and thus refusing the obvious, predictable and false approach given by their own countrymen.展开更多
基金financially supported by projects of the National Natural Science Foundation(No.42007171)the Hebei Natural Science Foundation(No.D2021504034)。
文摘The“tailing”effect caused by residual non-aqueous phase liquids(NAPLs)in porous aquifers is one of the frontiers in pollution hydrogeology research.Based on the current knowledge that the residual NAPLs is mainly controlled by the pore structure of soil,this study established a method for evaluating the residual saturation of NAPLs by investigating the fractal dimension of porous media.In this study,the soil column experiments of residual light NAPLs(LNAPLs)in sandy aquifer with different ratios of sands and soil were carried out,and the correlation between the fractal dimension of the medium,the residual of LNAPLs and the soil structure parameters are statistically analyzed,and its formation mechanism and main control factors are discussed.The results show that:Under our experimental condition:(1)the fractal dimension of the medium has a positive correlation with the residual saturation of NAPLs generally,and the optimal fitting function can be described by a quadratic model:S_(R)=192.02 D2-890.73 D+1040.8;(2)the dominant formation mechanism is:Smaller pores in the medium is related to larger fractal dimension,which leads to higher residual saturation of NAPLs;stronger heterogeneity of the medium is related to larger fractal dimension,which also leads to higher residual saturation of NAPLs;(3)the micro capillary pores characterized by fine sand are the main controlling factors of the formation mechanism.It is concluded that both the theory and the method of using fractal dimension of the medium to evaluate the residual saturation of NAPLs are feasible.This study provides a new perspective for the research of“tailing”effect of NAPLs in porous media aquifer.
文摘Non aqueous phase liquids (NAPLs) pollution are worldwide problems at present. NAPLs which enter the underground through spills or leaks may cause long lasting soil and groundwater contamination problems. Groundwater can be contaminated by non aqueous phase contaminants that are less dense (LNAPL) or denser (DNAPL) than water. The movement of both types of NAPLs will be influenced by the hydrogeological conditions, such as groundwater level, hydraulic conductivity, and porosity etc., however, LNAPL pollutants tend to concentrate at the water table while DNAPL may migrate further down. Understanding the underground migration mechanisms of NAPLs is of primary importance in pollution prediction and site remediation. Several laboratory simulations for NAPLs’ underground movements in porous media have been done in the past (A.S.Abdul et al., 1988, 1989; C.Tang et al., 1995). In this paper, we try to use STOMP (Subsurface Transport Over Multiple Phases) code to simulate the underground migration of NAPLs. The main purposes are: (1). to understand NAPLs’ underground migration mechanisms; (2). to analyze the sensitivities of model parameters, such as hydraulic conductivity, porosity, etc., and to know what are the most sensitive and important parameters in the model application; and (3). to study NAPLs movements in different hydrogeological conditions. The simulations include: Through the computer simulation, we have found that hydraulic conductivity and porosity are very sensitive in the model simulation, small changes of these parameters will cause big difference of the results, therefore, it is essential to accurately determine these parameters for high quality model simulation; The movements of NAPLs in different geological formation are quite different, two different geological media ( clayey sand and sand ) have been chosen in this paper to simulate NAPLs movement with different combinations ( i.e., moving from clayey sand to sand, and from sand to clayey sand ), the results have been analyzed and discussed; Finally, the influence of groundwater level variation to NAPLs (LNAPL and DNAPL) movement has been simulated by using pumping and injecting wells in the model. The results are compared with laboratory simulations conducted by C.Tang et al.. These results may helpful to understand the behavior of NAPLs during the remediation, such as pumping and treat, and air sparging. It is also important to the design of the remediation plans.
文摘The purpose of this study is to shed light on the southern part of Italy where Catalonians ruled. Great numbers of Spaniards, principally the Catalonians, headed to that country. This affected the language, and, in turn, the history of people＇s last names. At first, some of the Spanish last names were used as nicknames for Italians. The method 1 used to get the data from primary sources was from spending time in Italy for four consecutive summers and visiting towns in the Naples area while I collected surnames found on houses. The Catalonians came to rule Sardinia, and their language and subsequently Spanish were official on the island. The linguistic influence of Spanish does not stop with surnames. A list of Spanish and Basque surnames which is redolent of the history of southern Italy and Sicily is appended. The geolinguistics interest lies in the way that the study of language, both ordinary words and proper nouns, offers important clues to the lives and movements of people of ages past, reflects political and economic aspects and also explains the ethnic origin of people who live in Sicily and Italy today or are descendants of Italians who have been important immigrants in the Americas, in Australia, and indeed around the world.
文摘In this paper, we are interested by the dissolution of NAPL (Non-Aqueous Phase Liquid) contaminants in heterogeneous soils or aquifers. The volume averaging technique is applied to 2D systems with Darcy-scale heterogeneities. A large-scale model is derived from a Darcy-scale dissolution model in the case of small and large Damkholer numbers, i.e., for smooth or sharp dissolution fronts. The resulting models in both cases have the mathematical structure of a non-equilibrium dissolution model. It is shown how to calculate the resulting mass exchange and relative permeability terms from the Darcy-scale heterogeneities and other fluid properties. One of the important finding is that the obtained values have a very different behavior compared to the Darcy-scale usual correlations. The large scale correlations are also very different between the two limit cases. The resulting large-scale models are compared favorably to Darcy-scale direct simulations.
文摘Through an analysis of the accounts of English travellers in Naples between 1816 and 1841, the objective of this paper is to attempt to identify an image of the city and its inhabitants without following the direction of the usual negative stereotypes common to much of the literature associated with the ＂Grand Tourist＂, a literature to which scholars and readers from the 16th to the 19th century were used. The research also aims to demonstrate through previously unknown and unheeded sources that there were not only those English travellers on their Grand Tour of the post-Restoration Bourbon Mezzogiorno （southern Italy） looking for an opportunity of comparing their own civilization （which was considered far superior） to a more fragile reality. There were also other British people who had identified, with a critical eye and spirit of observation, the existence of a Naples and a south Italy which did not merely represent the sum of stereotypes and fallacies handed down through the centuries, and thus refusing the obvious, predictable and false approach given by their own countrymen.
