This study studied the characteristics and source apportionment of heavy metal pollution in the agricultural soil surrounding a gangue coal heap in Chongqing,China by using absolute principal component scores-multiple...This study studied the characteristics and source apportionment of heavy metal pollution in the agricultural soil surrounding a gangue coal heap in Chongqing,China by using absolute principal component scores-multiple linear regression(APCSMLR)model and positive matrix factorization(PMF)model.The applicability of the models was compared in the assessment of source apportionment.The results showed that the average contents of Cd,Hg,As,Pb,Cr,Cu,Ni,and Zn in the surface soil were 0.46,0.14,9.66,31.2,127,95.6,76.0,and 158 mg/kg,respectively.Combined with the spatial distribution and correlation analyses,the results of source apportionment were consistent for both the APCSMLR and PMF models.Cd,Hg,As,and Pb were mainly affected by the gangue heap accumulation,with respective contributions of 74.6%,79.4%,69.1%,and 67.2%based on the APCS-MLR model and respective contributions of 69.7%,60.7%,57.4%,and 41.9%based on the PMF model.Ni and Zn were mainly affected by industrial and agricultural activities,while Cr and Cu were mainly affected by natural factors.The results of the source apportionment were approximately consistent between the APCS-MLR and PMF models.The combined application of the two receptor models can make the results of source apportionment more comprehensive,accurate,and reliable.展开更多
Heap bioleaching is one of the most clean and economical processes for recovery of low-grade and complex ores, because the sulfide minerals are natural habitats for acidophiles capable of iron-and sulfur-oxidation. Th...Heap bioleaching is one of the most clean and economical processes for recovery of low-grade and complex ores, because the sulfide minerals are natural habitats for acidophiles capable of iron-and sulfur-oxidation. The most exciting advances in heap bioleaching are occurring in the field of microbiology, especially with the development of advanced molecular biology approaches. These chemolithotrophic microorganisms living in the acid mine environment fix N_2 and CO_2 and obtain energy for growth from soluble ferrous iron and reduced inorganic sulfur compounds during oxidation of sulfide minerals. The ferric iron as oxidant and sulfuric acid are a result of microbial activity and provide favorable conditions for the dissolution of sulfide minerals. Various microbial consortia were applied successfully in commercial bioleaching heaps around the world, and microbial community and activity were adapted related to the local climatic conditions, ore characteristics and engineering configuration. This review focuses on diversity of bioleaching microbes, their role in heap bioleaching processes, their community structure and function in industrial heaps and the relation to the ore characteristics and the engineering configuration, to give implications for optimizing leaching efficiency of heap bioleaching.展开更多
To explore a new evaluation method for spontaneous combustion tendency of different areas in sulfide ore heap, ore samples from a pyrite mine in China were taken as experimental materials, and the temperature variatio...To explore a new evaluation method for spontaneous combustion tendency of different areas in sulfide ore heap, ore samples from a pyrite mine in China were taken as experimental materials, and the temperature variations of the measuring points of simulated ore heap were measured. Combined with wavelet transform and nonlinear parameters extraction, a new method for spontaneous combustion tendency of different areas in sulfide ore heap based on nonlinear parameters was proposed and its reliability was verified by field test. The results indicate that temperature field evolution of the simulated ore heap presents significant spatial difference during self-heating process. Area with the maximum increasing extent of temperature in sulfide ore heap changes notably with the proceeding of self-heating reaction. Self-heating of sulfide ore heap is a chaotic evolution process, which means that it is feasible to evaluate spontaneous combustion tendency of different areas by nonlinear analysis method. There is a relatively strong correlation between the maximum Lyapunov exponent and spontaneous combustion tendency with the correlation coefficient of 0.9792. Furthermore, the sort of the maximum Lyapunov exponent is consistent with that of spontaneous combustion tendency. Therefore, spontaneous combustion tendency of different areas in sulfide ore heap can be evaluated by means of the maximum Lyapunov exponent method.展开更多
Bioleaching of chalcopyrite often encountered the formation of passivation layer, which inhibited the leaching process and resulted in a low leaching rate. This inhibitory effect can be eliminated by thermophilic biol...Bioleaching of chalcopyrite often encountered the formation of passivation layer, which inhibited the leaching process and resulted in a low leaching rate. This inhibitory effect can be eliminated by thermophilic biole- aching. The industrial test of BioCOP technology based on thermophiles was successfully completed, which confirmed the feasibility of chalcopyrite bioleaching. However, industrial leaching rate of chalcopyrite heap bioleaching is lower. This paper described the development status and industrial test of chalcopyrite heap bioleaching technology. The reasons for the lower efficiency of chalcopyrite heap bioleaching were analyzed. The strategies for successful chalcopyrite heap bioleaching were proposed.展开更多
Governing equations for a fully coupled flowing-reaction-deformation behavior with mass transfer in heap leaching are developed. The model equations are solved using an explicit finite difference method under the cond...Governing equations for a fully coupled flowing-reaction-deformation behavior with mass transfer in heap leaching are developed. The model equations are solved using an explicit finite difference method under the conditions of invariable application rate and constant hydraulic head. The distribution of the degree of the saturation, as well as the distributions of the concentration of the reagent and the solute is given. A cubic relationship between the mineral recovery and the leaching duration is obtained based on the numerical results. The relationship can be used to predict the recovery percentage of the valuable metal.展开更多
Recently a research team at Ohio University,USA,conducted a unique full-scale feld load test to simulate the aeration pipe installations at a copper extraction mine operated in Chile.The overliner material taken from ...Recently a research team at Ohio University,USA,conducted a unique full-scale feld load test to simulate the aeration pipe installations at a copper extraction mine operated in Chile.The overliner material taken from the mine was used in recreating the in situ conditions.Electric heaters were utilized to raise the temperature inside each pipe to simulate the essential element of the copper extraction process.The maximum vertical deflection reached by the test pipes was close to 20%,when the simulated heap pile height was 80 m.The plastic pipes and the overliner material were also tested in the laboratory.Based on the results,the maximum heap pile fll depth was recommended for the aeration system.The results indicated that the vertical deflection was the primary performance index for the aeration pipes installed in heap piles at mines.Lastly,the pipe made of polypropylene resin was super.展开更多
A mathematical model for heap bioleaching is developed to analyze heat transfer, oxygen flow, target ion distribution and oxidation leaching rate in the heap. The model equations are solved with Comsol Multiphysics so...A mathematical model for heap bioleaching is developed to analyze heat transfer, oxygen flow, target ion distribution and oxidation leaching rate in the heap. The model equations are solved with Comsol Multiphysics software. Numerical simulation results show the following facts: Concentration of oxygen is relatively high along the boundary of the slope, and low in the center part where leaching rate is slow. Temper- ature is relatively low along the slope and reaches the highest along the bottom region near the slope, with difference being more than 6℃. Concentration of target mental ions is the highest in the bottom region near the slope. Oxidation leaching rate is relatively large in the bottom and slope part with a fast reaction rate, and small in the other part with low oxygen concentration.展开更多
In 1986, G.X. Viennot introduced the theory of heaps of pieces as a visualization of Cartier and Foata’s “partially commutative monoids”. These are essentially labeled posets satisfying a few additional properties,...In 1986, G.X. Viennot introduced the theory of heaps of pieces as a visualization of Cartier and Foata’s “partially commutative monoids”. These are essentially labeled posets satisfying a few additional properties, and one natural setting where they arise is as models of reduced words in Coxeter groups. In this paper, we introduce a cyclic version of a heap, which loosely speaking, can be thought of as taking a heap and wrapping it into a cylinder. We call this object a toric heap, because we formalize it as a labeled toric poset, which is a cyclic version of an ordinary poset. Defining the category of toric heaps leads to the notion of certain morphisms such as toric extensions. We study toric heaps in Coxeter theory, because a cyclic shift of a reduced word is simply a conjugate by an initial or terminal generator. As such, we formalize and study a framework that we call cyclic reducibility in Coxeter theory, which is closely related to conjugacy. We introduce what it means for elements to be torically reduced, which is a stronger condition than simply being cyclically reduced. Along the way, we encounter a new class of elements that we call torically fully commutative (TFC), which are those that have a unique cyclic commutativity class, and comprise a strictly bigger class than the cyclically fully commutative (CFC) elements. We prove several cyclic analogues of results on fully commutative (FC) elements due to Stembridge. We conclude with how this framework fits into recent work in Coxeter groups, and we correct a minor flaw in a few recently published theorems.展开更多
A kind of heap sorting method based on array sorting was proposed. Some advantages and disadvantages of it were discussed. It was compared with the traditional method of direct application. In the method, the ordered ...A kind of heap sorting method based on array sorting was proposed. Some advantages and disadvantages of it were discussed. It was compared with the traditional method of direct application. In the method, the ordered keywords in the array are put into the heap one by one after building an empty heap. This method needs relatively less space and is fit for ordered sequence.展开更多
The refractory gold ores associated with rich copper and trapped in pyrite and quartz were studied. With conventional technique (all-sliming cyanidation), the gold recovery rate is only 51.78%. To eliminate the nega...The refractory gold ores associated with rich copper and trapped in pyrite and quartz were studied. With conventional technique (all-sliming cyanidation), the gold recovery rate is only 51.78%. To eliminate the negative effects of copper and pyrite on cyanidation and increase the gold recovery rate, the investigation on bio-heap leaching pretreatment was made, by which Cu would be dissolved and gold would be liberated from pyrite. The experiment adopted mixed bacteria, mainly ThiobaciUus ferrooxidan (named T.fl ), as the bacterial catalyst for bio-preconditioning and was carried out in a PVC column with a diameter of 20 cm and a height of 1.3 m loaded with gold ores. The temperature was controlled between 28 and 30℃, the pH value was kept between 2.0-2.5, and the flux of sprinkling bacterial liquid was maintained 0.80 L/h. After 45-day's bio-oxidization, among the samples sizing from 0 to 5 mm, the oxidation rates of Cu, Fe and S were respectively 44.62%, 28.16% and 25.46%, and the gold recovery rate by cyaniding increased to 80.35%. The bio-heap leaching pretreatment can therefore effectively dissolve Cu and liberate gold from pyrite and lead to the increase of gold extraction.展开更多
In order to analyze the deformation and stress characteristics of the pile foundation on the slope<span><span><span style="font-family:" capt",serif;"="" pro="" m...In order to analyze the deformation and stress characteristics of the pile foundation on the slope<span><span><span style="font-family:" capt",serif;"="" pro="" minion="">, </span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">this paper uses the finite element software Abaqus for numerical simulation.</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion=""> </span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">The displacement and stress data of pile under different working conditions (the combination of heap load and vertical load and horizontal load and inclined load) were collected</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">;</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">the distribution of pile displacement, axial force and bending moment were analyzed. Simulation results show that: slope top loading has little effect on vertical displacement</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">;</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion=""> when the heap load exceeds 200 kPa, the horizontal displacement is greatly affected. Pile axial force decreases with pile burial depth</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">;</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">pile lateral resistance plays a more adequate role in the rock and soil layer. The bending moment of double pile foundation is positive at the top and negative at the bottom.</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion=""> </span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">Applied oblique load has obvious p-Δ effect.</span></span></span>展开更多
The purpose of this work is to present an effective tool for computing different QR-decompositions of a complex nonsingular square matrix. The concept of the discrete signal-induced heap transform (DsiHT, Grigoryan 20...The purpose of this work is to present an effective tool for computing different QR-decompositions of a complex nonsingular square matrix. The concept of the discrete signal-induced heap transform (DsiHT, Grigoryan 2006) is used. This transform is fast, has a unique algorithm for any length of the input vector/signal and can be used with different complex basic 2 × 2 transforms. The DsiHT is zeroing all components of the input signal while moving or heaping the energy of the signal to one component, for instance the first one. We describe three different types of QR-decompositions that use the basic transforms with the T, G, and M-type complex matrices we introduce, as well as without matrices but using analytical formulas. We also present the mixed QR-decomposition, when different type DsiHTs are used in different stages of the algorithm. The number of such decompositions is greater than 3<sup>(N-1)</sup>, for an N × N complex matrix. Examples of the QR-decomposition are described in detail for the 4 × 4 and 6 × 6 complex matrices and compared with the known method of Householder transforms. The precision of the QR-decompositions of N × N matrices, when N are 6, 13, 17, 19, 21, 40, 64, 100, 128, 201, 256, and 400 is also compared. The MATLAB-based scripts of the codes for QR-decompositions by the described DsiHTs are given.展开更多
Based on the momentum and mass conservation equations,a comprehensive model of heap bioleaching process is developed to investigate the interaction between chemical reactions,solution flow,gas flow,and solute transpor...Based on the momentum and mass conservation equations,a comprehensive model of heap bioleaching process is developed to investigate the interaction between chemical reactions,solution flow,gas flow,and solute transport within the leaching system.The governing equations are solved numerically using the COMSOL Multiphysics software for the coupled reactive flow and solute transport at micro-scale,meso-scale and macro-scale levels.At or near the surface of ore particle,the acid concentration is relatively higher than that in the central area,while the concentration gradient decreases after 72 d of leaching.The flow simulation between ore particles by combining X-ray CT technology shows that the highest velocity in narrow pore reaches 0.375 m/s.The air velocity within the dump shows that the velocity near the top and side surface is relatively high,which leads to the high oxygen concentration in that area.The coupled heat transfer and liquid flow process shows that the solution can act as an effective remover from the heap,dropping the highest temperature from 60 to 38 °C.The reagent transfer coupled with solution flow is also analyzed.The results obtained allow us to obtain a better understanding of the fundamental physical phenomenon of the bioleaching process.展开更多
基金supported by Project of Chongqing Ecology and Environment Bureau(2021111)Project of Chongqing Science and Technology Bureau(cstc2022jxjl0005)。
文摘This study studied the characteristics and source apportionment of heavy metal pollution in the agricultural soil surrounding a gangue coal heap in Chongqing,China by using absolute principal component scores-multiple linear regression(APCSMLR)model and positive matrix factorization(PMF)model.The applicability of the models was compared in the assessment of source apportionment.The results showed that the average contents of Cd,Hg,As,Pb,Cr,Cu,Ni,and Zn in the surface soil were 0.46,0.14,9.66,31.2,127,95.6,76.0,and 158 mg/kg,respectively.Combined with the spatial distribution and correlation analyses,the results of source apportionment were consistent for both the APCSMLR and PMF models.Cd,Hg,As,and Pb were mainly affected by the gangue heap accumulation,with respective contributions of 74.6%,79.4%,69.1%,and 67.2%based on the APCS-MLR model and respective contributions of 69.7%,60.7%,57.4%,and 41.9%based on the PMF model.Ni and Zn were mainly affected by industrial and agricultural activities,while Cr and Cu were mainly affected by natural factors.The results of the source apportionment were approximately consistent between the APCS-MLR and PMF models.The combined application of the two receptor models can make the results of source apportionment more comprehensive,accurate,and reliable.
基金funded by the National Natural Science Foundation of China(41401541,51674231)Bureau of International Co-operation,Chinese Academy of Sciences(122111KYSB20150013)
文摘Heap bioleaching is one of the most clean and economical processes for recovery of low-grade and complex ores, because the sulfide minerals are natural habitats for acidophiles capable of iron-and sulfur-oxidation. The most exciting advances in heap bioleaching are occurring in the field of microbiology, especially with the development of advanced molecular biology approaches. These chemolithotrophic microorganisms living in the acid mine environment fix N_2 and CO_2 and obtain energy for growth from soluble ferrous iron and reduced inorganic sulfur compounds during oxidation of sulfide minerals. The ferric iron as oxidant and sulfuric acid are a result of microbial activity and provide favorable conditions for the dissolution of sulfide minerals. Various microbial consortia were applied successfully in commercial bioleaching heaps around the world, and microbial community and activity were adapted related to the local climatic conditions, ore characteristics and engineering configuration. This review focuses on diversity of bioleaching microbes, their role in heap bioleaching processes, their community structure and function in industrial heaps and the relation to the ore characteristics and the engineering configuration, to give implications for optimizing leaching efficiency of heap bioleaching.
基金Projects(51304238,51534008)supported by the National Natural Science Foundation of ChinaProject(2015CX005)supported by Innovation Driven Plan of Central South University,China
文摘To explore a new evaluation method for spontaneous combustion tendency of different areas in sulfide ore heap, ore samples from a pyrite mine in China were taken as experimental materials, and the temperature variations of the measuring points of simulated ore heap were measured. Combined with wavelet transform and nonlinear parameters extraction, a new method for spontaneous combustion tendency of different areas in sulfide ore heap based on nonlinear parameters was proposed and its reliability was verified by field test. The results indicate that temperature field evolution of the simulated ore heap presents significant spatial difference during self-heating process. Area with the maximum increasing extent of temperature in sulfide ore heap changes notably with the proceeding of self-heating reaction. Self-heating of sulfide ore heap is a chaotic evolution process, which means that it is feasible to evaluate spontaneous combustion tendency of different areas by nonlinear analysis method. There is a relatively strong correlation between the maximum Lyapunov exponent and spontaneous combustion tendency with the correlation coefficient of 0.9792. Furthermore, the sort of the maximum Lyapunov exponent is consistent with that of spontaneous combustion tendency. Therefore, spontaneous combustion tendency of different areas in sulfide ore heap can be evaluated by means of the maximum Lyapunov exponent method.
基金supported by the National High Technology Research and Development Program (Nos. 2012AA061501, 2012AA061502)the National Natural Science Foundation of China (No. 50934002)
文摘Bioleaching of chalcopyrite often encountered the formation of passivation layer, which inhibited the leaching process and resulted in a low leaching rate. This inhibitory effect can be eliminated by thermophilic biole- aching. The industrial test of BioCOP technology based on thermophiles was successfully completed, which confirmed the feasibility of chalcopyrite bioleaching. However, industrial leaching rate of chalcopyrite heap bioleaching is lower. This paper described the development status and industrial test of chalcopyrite heap bioleaching technology. The reasons for the lower efficiency of chalcopyrite heap bioleaching were analyzed. The strategies for successful chalcopyrite heap bioleaching were proposed.
基金Project supported by the National Basic Research and Development Program of China (No.2004CB619206)the National Science Fund for Distinguished Young Scholars (No.50325415)+1 种基金the National Science Fund for Innovative Research Group (No.50321402)the Natural Science Foundation of Hunan Province (No.06JJ30024)
文摘Governing equations for a fully coupled flowing-reaction-deformation behavior with mass transfer in heap leaching are developed. The model equations are solved using an explicit finite difference method under the conditions of invariable application rate and constant hydraulic head. The distribution of the degree of the saturation, as well as the distributions of the concentration of the reagent and the solute is given. A cubic relationship between the mineral recovery and the leaching duration is obtained based on the numerical results. The relationship can be used to predict the recovery percentage of the valuable metal.
文摘Recently a research team at Ohio University,USA,conducted a unique full-scale feld load test to simulate the aeration pipe installations at a copper extraction mine operated in Chile.The overliner material taken from the mine was used in recreating the in situ conditions.Electric heaters were utilized to raise the temperature inside each pipe to simulate the essential element of the copper extraction process.The maximum vertical deflection reached by the test pipes was close to 20%,when the simulated heap pile height was 80 m.The plastic pipes and the overliner material were also tested in the laboratory.Based on the results,the maximum heap pile fll depth was recommended for the aeration system.The results indicated that the vertical deflection was the primary performance index for the aeration pipes installed in heap piles at mines.Lastly,the pipe made of polypropylene resin was super.
基金Project supported by the National Natural Science Foundation of China (Nos. 50934002 and 50774011)the Postdoctoral Science Foundation of China (No. 20090450014)the DoctoralNatural Science Foundation of China (No. 20070008038)
文摘A mathematical model for heap bioleaching is developed to analyze heat transfer, oxygen flow, target ion distribution and oxidation leaching rate in the heap. The model equations are solved with Comsol Multiphysics software. Numerical simulation results show the following facts: Concentration of oxygen is relatively high along the boundary of the slope, and low in the center part where leaching rate is slow. Temper- ature is relatively low along the slope and reaches the highest along the bottom region near the slope, with difference being more than 6℃. Concentration of target mental ions is the highest in the bottom region near the slope. Oxidation leaching rate is relatively large in the bottom and slope part with a fast reaction rate, and small in the other part with low oxygen concentration.
文摘In 1986, G.X. Viennot introduced the theory of heaps of pieces as a visualization of Cartier and Foata’s “partially commutative monoids”. These are essentially labeled posets satisfying a few additional properties, and one natural setting where they arise is as models of reduced words in Coxeter groups. In this paper, we introduce a cyclic version of a heap, which loosely speaking, can be thought of as taking a heap and wrapping it into a cylinder. We call this object a toric heap, because we formalize it as a labeled toric poset, which is a cyclic version of an ordinary poset. Defining the category of toric heaps leads to the notion of certain morphisms such as toric extensions. We study toric heaps in Coxeter theory, because a cyclic shift of a reduced word is simply a conjugate by an initial or terminal generator. As such, we formalize and study a framework that we call cyclic reducibility in Coxeter theory, which is closely related to conjugacy. We introduce what it means for elements to be torically reduced, which is a stronger condition than simply being cyclically reduced. Along the way, we encounter a new class of elements that we call torically fully commutative (TFC), which are those that have a unique cyclic commutativity class, and comprise a strictly bigger class than the cyclically fully commutative (CFC) elements. We prove several cyclic analogues of results on fully commutative (FC) elements due to Stembridge. We conclude with how this framework fits into recent work in Coxeter groups, and we correct a minor flaw in a few recently published theorems.
文摘A kind of heap sorting method based on array sorting was proposed. Some advantages and disadvantages of it were discussed. It was compared with the traditional method of direct application. In the method, the ordered keywords in the array are put into the heap one by one after building an empty heap. This method needs relatively less space and is fit for ordered sequence.
文摘The refractory gold ores associated with rich copper and trapped in pyrite and quartz were studied. With conventional technique (all-sliming cyanidation), the gold recovery rate is only 51.78%. To eliminate the negative effects of copper and pyrite on cyanidation and increase the gold recovery rate, the investigation on bio-heap leaching pretreatment was made, by which Cu would be dissolved and gold would be liberated from pyrite. The experiment adopted mixed bacteria, mainly ThiobaciUus ferrooxidan (named T.fl ), as the bacterial catalyst for bio-preconditioning and was carried out in a PVC column with a diameter of 20 cm and a height of 1.3 m loaded with gold ores. The temperature was controlled between 28 and 30℃, the pH value was kept between 2.0-2.5, and the flux of sprinkling bacterial liquid was maintained 0.80 L/h. After 45-day's bio-oxidization, among the samples sizing from 0 to 5 mm, the oxidation rates of Cu, Fe and S were respectively 44.62%, 28.16% and 25.46%, and the gold recovery rate by cyaniding increased to 80.35%. The bio-heap leaching pretreatment can therefore effectively dissolve Cu and liberate gold from pyrite and lead to the increase of gold extraction.
文摘In order to analyze the deformation and stress characteristics of the pile foundation on the slope<span><span><span style="font-family:" capt",serif;"="" pro="" minion="">, </span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">this paper uses the finite element software Abaqus for numerical simulation.</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion=""> </span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">The displacement and stress data of pile under different working conditions (the combination of heap load and vertical load and horizontal load and inclined load) were collected</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">;</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">the distribution of pile displacement, axial force and bending moment were analyzed. Simulation results show that: slope top loading has little effect on vertical displacement</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">;</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion=""> when the heap load exceeds 200 kPa, the horizontal displacement is greatly affected. Pile axial force decreases with pile burial depth</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">;</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">pile lateral resistance plays a more adequate role in the rock and soil layer. The bending moment of double pile foundation is positive at the top and negative at the bottom.</span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion=""> </span></span></span><span><span><span style="font-family:" capt",serif;"="" pro="" minion="">Applied oblique load has obvious p-Δ effect.</span></span></span>
文摘The purpose of this work is to present an effective tool for computing different QR-decompositions of a complex nonsingular square matrix. The concept of the discrete signal-induced heap transform (DsiHT, Grigoryan 2006) is used. This transform is fast, has a unique algorithm for any length of the input vector/signal and can be used with different complex basic 2 × 2 transforms. The DsiHT is zeroing all components of the input signal while moving or heaping the energy of the signal to one component, for instance the first one. We describe three different types of QR-decompositions that use the basic transforms with the T, G, and M-type complex matrices we introduce, as well as without matrices but using analytical formulas. We also present the mixed QR-decomposition, when different type DsiHTs are used in different stages of the algorithm. The number of such decompositions is greater than 3<sup>(N-1)</sup>, for an N × N complex matrix. Examples of the QR-decomposition are described in detail for the 4 × 4 and 6 × 6 complex matrices and compared with the known method of Householder transforms. The precision of the QR-decompositions of N × N matrices, when N are 6, 13, 17, 19, 21, 40, 64, 100, 128, 201, 256, and 400 is also compared. The MATLAB-based scripts of the codes for QR-decompositions by the described DsiHTs are given.
基金Projects(50934002,51104011) supported by the National Natural Science Foundation of ChinaProject(IRT0950) supported by Program for Changjiang Scholars and Innovative Research Team in Chinese UniversityProject(20100480200) supported by China Postdoctoral Science Foundation
文摘Based on the momentum and mass conservation equations,a comprehensive model of heap bioleaching process is developed to investigate the interaction between chemical reactions,solution flow,gas flow,and solute transport within the leaching system.The governing equations are solved numerically using the COMSOL Multiphysics software for the coupled reactive flow and solute transport at micro-scale,meso-scale and macro-scale levels.At or near the surface of ore particle,the acid concentration is relatively higher than that in the central area,while the concentration gradient decreases after 72 d of leaching.The flow simulation between ore particles by combining X-ray CT technology shows that the highest velocity in narrow pore reaches 0.375 m/s.The air velocity within the dump shows that the velocity near the top and side surface is relatively high,which leads to the high oxygen concentration in that area.The coupled heat transfer and liquid flow process shows that the solution can act as an effective remover from the heap,dropping the highest temperature from 60 to 38 °C.The reagent transfer coupled with solution flow is also analyzed.The results obtained allow us to obtain a better understanding of the fundamental physical phenomenon of the bioleaching process.