This study examines the use of intact samples as an alternative to powder in conventional batch sorption studies to determine the distribution coefficient(K_d).Stable cesium(^(133)Cs) and strontium(^(87)Sr) were used ...This study examines the use of intact samples as an alternative to powder in conventional batch sorption studies to determine the distribution coefficient(K_d).Stable cesium(^(133)Cs) and strontium(^(87)Sr) were used under specified geochemical conditions to compare the Kdvalues of powder and block pumice tuff samples. The aim of the study was to infer any Kddifference under laboratory and field conditions. Kdvalues for block samples were found to be less than one order of magnitude lower than powder materials for both Cs and Sr on fresh tuff, and more than one order of magnitude lower in oxidized tuff. Destruction of micropores in oxidized tuff was estimated to be mainly responsible for reducing Kdvalues in oxidized tuff. However, approximately one order of magnitude difference in Kdvalues indicates that homogenously prepared intact samples can be used for sorption coefficient measurement at closer to in situ conditions. Pore size distribution analysis using mercury intrusion porosimetry revealed that lower Kdvalues on block samples result from lower surface area available as sorption sites due to inaccessible closed pores in the intact solid.展开更多
As it is commonly known,the estimation of physical and mechanical characteristics of rocks is very important issue in various geotechnical projects.The characteristics are mainly influenced by the microfabric-texture ...As it is commonly known,the estimation of physical and mechanical characteristics of rocks is very important issue in various geotechnical projects.The characteristics are mainly influenced by the microfabric-texture features of rocks.In this research,dry unit weight,effective porosity,point load index,Schmidt rebound hardness,uniaxial compressive strength,and texture coefficient were measured with the aim of correlating the physical and mechanical properties to the texture coefficient.For this purpose,a comprehensive laboratory testing program was conducted after collecting twenty sedimentary block samples including nine limestones and eleven mudstones,taken from Kalidromo(central Greece)in accordance with ASTM and ISRM standards.Also,mineralogical and petrographic properties,textural characteristics as well as X-ray diffractions were studied and the obtained results were statistically described and analysed.The maximum and minimum values of the texture coefficient were 0.13 and 0.50,respectively.The highest value was obtained for the rocks with a large amount of grains.Regression analyses were used to investigate the relationships between the texture coefficient and the engineering properties.Thus,empirical equations were developed and because of the good determination coefficients,they showed that all of the engineering properties were well correlated to the texture coefficient.展开更多
Knowledge and management of soil pH, particularly soil acidity across spatially variable soils is important, although this is greatly ignored by farmers. The objective of the study was to evaluate in-field spatial var...Knowledge and management of soil pH, particularly soil acidity across spatially variable soils is important, although this is greatly ignored by farmers. The objective of the study was to evaluate in-field spatial variability of soil pH, and compare the efficiency of managing soil pH through site-specific method vs. uniform lime application. The study was conducted on three sites with study sites I and II （23°50＇ S; 29°40＇ E）, and study sites IIl （23°59＇ S; 28°52＇ E） adjacent to each other in the semi-arid regions of the Limpopo Province, South Africa. Soil samples were taken in four replicates from geo-referenced locations on a regular grid of 30 m. Soils were analyzed for pH, and SMP buffer pH. Soil maps were produced with Geographic Information System （GIS） software, and soil pH datasets were interpolated using a geostatistical tool of inverse distance weighing （IDW）. Soil pH in the fields varied from 3.93 to 7.00. An excess amount of lime as high as 30 t/ha under uniform lime application were recorded. These recommendations were in excess on field areas that needed little or no lime applications. Again, there was an under applications of lime as much as 35 t/ha for uniform liming applications. This under- and over-recommendations of lime based on average soil pH values suggests that uniform soil acidity correction and soil pH management strategy is not an appropriate strategy to be adopted in these fields with spatially variable soils. The field can be divided into lime application zones of （1） high rates of lime, （2） low rates of lime and （3） areas that requires no lime at all so that lime rates are applied per zone. A key to site-specific soil acidity correction with lime is to reach ideal soil pH for the crop in all parts of the field.展开更多
The mobile factors of cracked ore in vibrating-ore draw shafts were analyzed. The results show that the mobile coefficient of cracked ores will be mainly influenced by the combination of ore physical factors if the st...The mobile factors of cracked ore in vibrating-ore draw shafts were analyzed. The results show that the mobile coefficient of cracked ores will be mainly influenced by the combination of ore physical factors if the structure dimension and parameters of vibrating ore-draw shafts are sure. It decreases with increasing the cohesion, lump content, lump size and powder content and increases with increasing the porosity. The coefficient decreases with increasing the moisture content, but increases after the moisture content reaches a certain value. Uniform grain leads to better mobility, non-uniform grain leads to worse mobility. The value of the mobile coefficient should be in a range of 0.3-1.1 when designing the vibrating ore-draw shafts. According to correlation degree of grey system (theory,) the effects of factors on the mobility of cracked ore are given in the weight decreasing consequence as follows: moisture content, lump content, distribution of grain size, lump size, porosity, cohesion and powder ore content. It is unreasonable to neglect any one because the values of their weights are not obvious.展开更多
In this paper, we propose the statistical space mapping thought and classify the seismic body space throughlithology space clustering combining to the actual application background of petroleum exploration. A new meth...In this paper, we propose the statistical space mapping thought and classify the seismic body space throughlithology space clustering combining to the actual application background of petroleum exploration. A new method ofstratum petroleum recognition based on neural network was set up through the foundation of the data mapping relationbetween log and seismic body. It can break a new path for recognition petroleum using both log and seismic data. Andthis method has been validated in the practical data analysis in Liaohe oil field.展开更多
The main purpose of current study is development of an intelligent model for estimation of shear wave velocity in limestone. Shear wave velocity is one of the most important rock dynamic parameters. Because rocks have...The main purpose of current study is development of an intelligent model for estimation of shear wave velocity in limestone. Shear wave velocity is one of the most important rock dynamic parameters. Because rocks have complicated structure, direct determination of this parameter takes time, spends expenditure and requires accuracy. On the other hand, there are no precise equations for indirect determination of it; most of them are empirical. By using data sets of several dams of Iran and neuro-genetic, adaptive neuro-fuzzy inference system （ANFIS）, and gene expression programming （GEP） methods, models are rendered for prediction of shear wave velocity in limestone. Totally, 516 sets of data has been used for modeling. From these data sets, 413 ones have been utilized for building the intelligent model, and 103 have been used for their performance evaluation. Compressional wave velocity （Vp）, density （7） and porosity （.n）, were considered as input parameters. Respectively, the amount of R for neuro-genetic and ANFIS networks was 0.959 and 0.963. In addition, by using GEP, three equations are obtained; the best of them has 0.958R. ANFIS shows the best prediction results, whereas GEP indicates proper equations. Because these equations have accuracy, they could be used for prediction of shear wave velocity for limestone in the future.展开更多
Root proliferation can be stimulated in a heterogeneous nutrient patch; however, the functions of the root proliferation in the nutrient-rich soil patches are not fully understood. In the present study, a two-year fie...Root proliferation can be stimulated in a heterogeneous nutrient patch; however, the functions of the root proliferation in the nutrient-rich soil patches are not fully understood. In the present study, a two-year field experiment was conducted to examine the comparative effects of localized application of ammonium and phosphorus (P) at early or late stages on root growth, nutrient uptake, and biomass of maize (Zea mays L.) on a calcareous soil in an intensive farming system. Localized supply of ammonium and P had a more evident effect on shoot and root growth, and especially stimulated fine root development at the early seedling stage, with most of the maize roots being allocated to the nutrient-rich patch in the topsoil. Although localized ammonium and P supply at the late stage also enhanced the fine root growth, the plant roots in the patch accounted for a low proportion of the whole maize roots in the topsoil at the flowering stage. Compared with the early stage, fine root length in the short-lived nutrient patch decreased by 44%-62% and the shoot dry weight was not different between heterogeneous and homogeneous nutrient supply at the late growth stage. Localized supply of ammonium and P significantly increased N and P accumulation by maize at 35 and 47 days after sowing (DAS); however, no significant difference was found among the treatments at 82 DAS and the later growth stages. The increased nutrient uptake and plant growth was related to the higher proportion of root length in the localized nutrient-enriched patch. The results indicated that root proliferation in nutrient patches contributed more to maize growth and nutrient uptake at the early than late stages.展开更多
文摘This study examines the use of intact samples as an alternative to powder in conventional batch sorption studies to determine the distribution coefficient(K_d).Stable cesium(^(133)Cs) and strontium(^(87)Sr) were used under specified geochemical conditions to compare the Kdvalues of powder and block pumice tuff samples. The aim of the study was to infer any Kddifference under laboratory and field conditions. Kdvalues for block samples were found to be less than one order of magnitude lower than powder materials for both Cs and Sr on fresh tuff, and more than one order of magnitude lower in oxidized tuff. Destruction of micropores in oxidized tuff was estimated to be mainly responsible for reducing Kdvalues in oxidized tuff. However, approximately one order of magnitude difference in Kdvalues indicates that homogenously prepared intact samples can be used for sorption coefficient measurement at closer to in situ conditions. Pore size distribution analysis using mercury intrusion porosimetry revealed that lower Kdvalues on block samples result from lower surface area available as sorption sites due to inaccessible closed pores in the intact solid.
文摘As it is commonly known,the estimation of physical and mechanical characteristics of rocks is very important issue in various geotechnical projects.The characteristics are mainly influenced by the microfabric-texture features of rocks.In this research,dry unit weight,effective porosity,point load index,Schmidt rebound hardness,uniaxial compressive strength,and texture coefficient were measured with the aim of correlating the physical and mechanical properties to the texture coefficient.For this purpose,a comprehensive laboratory testing program was conducted after collecting twenty sedimentary block samples including nine limestones and eleven mudstones,taken from Kalidromo(central Greece)in accordance with ASTM and ISRM standards.Also,mineralogical and petrographic properties,textural characteristics as well as X-ray diffractions were studied and the obtained results were statistically described and analysed.The maximum and minimum values of the texture coefficient were 0.13 and 0.50,respectively.The highest value was obtained for the rocks with a large amount of grains.Regression analyses were used to investigate the relationships between the texture coefficient and the engineering properties.Thus,empirical equations were developed and because of the good determination coefficients,they showed that all of the engineering properties were well correlated to the texture coefficient.
文摘Knowledge and management of soil pH, particularly soil acidity across spatially variable soils is important, although this is greatly ignored by farmers. The objective of the study was to evaluate in-field spatial variability of soil pH, and compare the efficiency of managing soil pH through site-specific method vs. uniform lime application. The study was conducted on three sites with study sites I and II （23°50＇ S; 29°40＇ E）, and study sites IIl （23°59＇ S; 28°52＇ E） adjacent to each other in the semi-arid regions of the Limpopo Province, South Africa. Soil samples were taken in four replicates from geo-referenced locations on a regular grid of 30 m. Soils were analyzed for pH, and SMP buffer pH. Soil maps were produced with Geographic Information System （GIS） software, and soil pH datasets were interpolated using a geostatistical tool of inverse distance weighing （IDW）. Soil pH in the fields varied from 3.93 to 7.00. An excess amount of lime as high as 30 t/ha under uniform lime application were recorded. These recommendations were in excess on field areas that needed little or no lime applications. Again, there was an under applications of lime as much as 35 t/ha for uniform liming applications. This under- and over-recommendations of lime based on average soil pH values suggests that uniform soil acidity correction and soil pH management strategy is not an appropriate strategy to be adopted in these fields with spatially variable soils. The field can be divided into lime application zones of （1） high rates of lime, （2） low rates of lime and （3） areas that requires no lime at all so that lime rates are applied per zone. A key to site-specific soil acidity correction with lime is to reach ideal soil pH for the crop in all parts of the field.
基金Project(50325415) supported by the National Science Fund for Distinguished Young Scholars project(50321402) sup ported by the National Science Fund for Innovative Research Group
文摘The mobile factors of cracked ore in vibrating-ore draw shafts were analyzed. The results show that the mobile coefficient of cracked ores will be mainly influenced by the combination of ore physical factors if the structure dimension and parameters of vibrating ore-draw shafts are sure. It decreases with increasing the cohesion, lump content, lump size and powder content and increases with increasing the porosity. The coefficient decreases with increasing the moisture content, but increases after the moisture content reaches a certain value. Uniform grain leads to better mobility, non-uniform grain leads to worse mobility. The value of the mobile coefficient should be in a range of 0.3-1.1 when designing the vibrating ore-draw shafts. According to correlation degree of grey system (theory,) the effects of factors on the mobility of cracked ore are given in the weight decreasing consequence as follows: moisture content, lump content, distribution of grain size, lump size, porosity, cohesion and powder ore content. It is unreasonable to neglect any one because the values of their weights are not obvious.
文摘In this paper, we propose the statistical space mapping thought and classify the seismic body space throughlithology space clustering combining to the actual application background of petroleum exploration. A new method ofstratum petroleum recognition based on neural network was set up through the foundation of the data mapping relationbetween log and seismic body. It can break a new path for recognition petroleum using both log and seismic data. Andthis method has been validated in the practical data analysis in Liaohe oil field.
文摘The main purpose of current study is development of an intelligent model for estimation of shear wave velocity in limestone. Shear wave velocity is one of the most important rock dynamic parameters. Because rocks have complicated structure, direct determination of this parameter takes time, spends expenditure and requires accuracy. On the other hand, there are no precise equations for indirect determination of it; most of them are empirical. By using data sets of several dams of Iran and neuro-genetic, adaptive neuro-fuzzy inference system （ANFIS）, and gene expression programming （GEP） methods, models are rendered for prediction of shear wave velocity in limestone. Totally, 516 sets of data has been used for modeling. From these data sets, 413 ones have been utilized for building the intelligent model, and 103 have been used for their performance evaluation. Compressional wave velocity （Vp）, density （7） and porosity （.n）, were considered as input parameters. Respectively, the amount of R for neuro-genetic and ANFIS networks was 0.959 and 0.963. In addition, by using GEP, three equations are obtained; the best of them has 0.958R. ANFIS shows the best prediction results, whereas GEP indicates proper equations. Because these equations have accuracy, they could be used for prediction of shear wave velocity for limestone in the future.
基金Supported by the National Natural Science Foundation of China (NSFC) (Nos. 30890131 and 30925024)the Innovative Group Grant of the NSFC (No. 31121062)the Program of Introducing International Advanced Agricultural Science and Technology of the Ministry of Agriculture of China (948 Program) (No. 2011-G18)
文摘Root proliferation can be stimulated in a heterogeneous nutrient patch; however, the functions of the root proliferation in the nutrient-rich soil patches are not fully understood. In the present study, a two-year field experiment was conducted to examine the comparative effects of localized application of ammonium and phosphorus (P) at early or late stages on root growth, nutrient uptake, and biomass of maize (Zea mays L.) on a calcareous soil in an intensive farming system. Localized supply of ammonium and P had a more evident effect on shoot and root growth, and especially stimulated fine root development at the early seedling stage, with most of the maize roots being allocated to the nutrient-rich patch in the topsoil. Although localized ammonium and P supply at the late stage also enhanced the fine root growth, the plant roots in the patch accounted for a low proportion of the whole maize roots in the topsoil at the flowering stage. Compared with the early stage, fine root length in the short-lived nutrient patch decreased by 44%-62% and the shoot dry weight was not different between heterogeneous and homogeneous nutrient supply at the late growth stage. Localized supply of ammonium and P significantly increased N and P accumulation by maize at 35 and 47 days after sowing (DAS); however, no significant difference was found among the treatments at 82 DAS and the later growth stages. The increased nutrient uptake and plant growth was related to the higher proportion of root length in the localized nutrient-enriched patch. The results indicated that root proliferation in nutrient patches contributed more to maize growth and nutrient uptake at the early than late stages.
