Sustainable energy sources are an immediate need to cope with the imminent issue of climate change the world is facing today.In particular,the long-lasting miniatured power sources that can supply energy continually t...Sustainable energy sources are an immediate need to cope with the imminent issue of climate change the world is facing today.In particular,the long-lasting miniatured power sources that can supply energy continually to power handheld gadgets,sensors,electronic devices,unmanned airborne vehicles in space and extreme mining are some of the examples where this is an acute need.It is known from basic physics that radioactive materials decay over few years and some nuclear materials have their half-life until thousands of years.The past five decades of research have been spent harnessing the decay energy of the radioactive materials to develop batteries that can last until the radioactive reaction continues.Thus,an emergent opportunity of industrial symbiosis to make use of nuclear waste by using radioactive waste as raw material to develop bat-teries with long shelf life presents a great opportunity for sustainable energy resource development.However,the current canon of research on this topic is scarce.This perspective draws fresh discussions on the topic while highlighting future directions in this wealthy arena of research.Graphical abstract A long-lasting miniaturised nuclear battery utilising 14C radioactive isotope as fuel.展开更多
In order to research whether it is suitable to set a geological disposal repository for high-level radioactive nuclear waste into one target granite body,two active source seismic profles were arranged near a small to...In order to research whether it is suitable to set a geological disposal repository for high-level radioactive nuclear waste into one target granite body,two active source seismic profles were arranged near a small town named Tamusu,Western China.The study area is with complex surface conditions,thus the seismic exploration encountered a variettraveltimey of technical difculties such as crossing obstacles,de-noising harmful scattered waves,and building complex near-surface velocity models.In order to address those problems,techniques including cross-obstacle seismic geometry design,angle-domain harmful scattered noise removal,and an acoustic wave equation-based inversion method jointly utilizing both the and waveform of frst arrival waves were adopted.The fnal seismic images clearly exhibit the target rock’s unconformable contact boundary and its top interface beneath the sedimentary and weathered layers.On this basis,it could be confrmed that the target rock is not thin or has been transported by geological process from somewhere else,but a native and massive rock.There are a few small size fractures whose space distribution could be revealed by seismic images within the rock.The fractures should be kept away.Based on current research,it could be considered that active source seismic exploration is demanded during the sitting process of the geological disposal repository for nuclear waste.The seismic acquisition and processing techniques proposed in the present paper would ofer a good reference value for similar researches in the future.展开更多
We reported a rapid synthesis of Sm^(3+)/Zr^(4+)co-doped Gd2Ti2O7 pyrochlore simulated nuclear wastes solidification by self-propagation plus quick pressing technique.With increment excess contents of Sm2O3 and ZrO2 f...We reported a rapid synthesis of Sm^(3+)/Zr^(4+)co-doped Gd2Ti2O7 pyrochlore simulated nuclear wastes solidification by self-propagation plus quick pressing technique.With increment excess contents of Sm2O3 and ZrO2 from 0 to 10wt%,the phase composition of the products is a mixed phase of pyrochlore structure and defective fluorite structure by X-ray diffraction(XRD)analysis and Raman spectrum.In addition,the SEM results demonstrate the fracture surface and microstructure of Gd2Ti2O7-based pyrochlore.The densified pyrochlore waste form exhibits high bulk density of 5.56 g·cm^(-3) and vickers hardness of 11.20±0.2 GPa.The leaching tests show that the elemental leaching rates of Gd,Sm,and Cu after 42 days are 1.92×10^(-4),1.51×10^(-4),and 3.90×10^(-3) g·m^(-2)·d^(-1),respectively.展开更多
A complex Sol-Gel process has been used for synthesis of silica glasses designed to contain high-level nuclear wastes. Cs, Sr, Co, and Nd (generically denoted Me) were used, the last as surrogate for actinides. Gels i...A complex Sol-Gel process has been used for synthesis of silica glasses designed to contain high-level nuclear wastes. Cs, Sr, Co, and Nd (generically denoted Me) were used, the last as surrogate for actinides. Gels in the form of powders and sintered compacts were prepared by hydrolysis and polycondensation of tetraethoxide/Me nitrate solutions, which contained ascorbic acid as a catalyst. Thermal treatment studies were conducted on the resulting gels. Transformation to final products was studied by thermogravimetric analysis, infrared spectroscopy, and X-ray diffraction. Preliminary testing of Me leaching was also completed in quiescent water. Only a single dense form was resistant to展开更多
The properties of a Lanthanum bromide(LaBr3)detector and its response functions were investigated via experiments and simulations in this paper.The LaBr3detector had good relative energy resolution and higher efficien...The properties of a Lanthanum bromide(LaBr3)detector and its response functions were investigated via experiments and simulations in this paper.The LaBr3detector had good relative energy resolution and higher efficiency than a high-purity germanium detector.Monte Carlo and other numerical methods were used to calculate the efficiencies of a LaBr3detector with a square collimation window.A model of the numerical method was established based on a pure geometric model that was consistent with the experimental situation.The results showed that the detector response functions calculated by these methods were in great agreement with experimental results.展开更多
A set of potential parameters for modeling zircon was obtained by atomistic simulation techniques and a reasonable structural model of zircon was established by fitting some important properties of zircon.Based on the...A set of potential parameters for modeling zircon was obtained by atomistic simulation techniques and a reasonable structural model of zircon was established by fitting some important properties of zircon.Based on the equilibrium configuration of zircon, authors calculated the formation energies of basic point defects and intrinsic disorders. The heats of solution of substituting Pu for Zr showed that there was an immiscible gap at the composition of (Pu75%-Zr25%, in mole fraction), which suggests that the amount of Pu substituting for Zr in zircon be≤50%.展开更多
Abstract A system of quasilinear coupled equations which arise from simulation of contamination of geologic nulear waste in porous media is studied. We’ll discuss Galerkin method for the model of compressible flow wi...Abstract A system of quasilinear coupled equations which arise from simulation of contamination of geologic nulear waste in porous media is studied. We’ll discuss Galerkin method for the model of compressible flow with molecular diffusion and dispersion. Some new techniques are introcued to error analysis. Only one dimensional case is considered. The optimal error estimate in both L^2 and H^1 is proved. A contribution of this paper is how the dispersion term can be handled,展开更多
The main objective of this paper is to analyze the current status of high-level nuclear waste disposal along with presentation of practical perspectives about the environmental issues involved. Present disposal design...The main objective of this paper is to analyze the current status of high-level nuclear waste disposal along with presentation of practical perspectives about the environmental issues involved. Present disposal designs and concepts are analyzed on a scientific basis and modifications to existing designs are proposed from the perspective of environmental safety. A new concept of a chemical heat sink is introduced for the removal of heat emitted due to radioactive decay in the spent nuclear fuel or high-level radioactive waste, and thermal spikes produced by radiation in containment materials. Mainly, UO2 and metallic U are used as fuels in nuclear reactors. Spent nuclear fuel contains fission products and transuranium elements which would remain radioactive for 104 to 108years. Essential concepts and engineering strategies for spent nuclear fuel disposal are described. Conceptual designs are described and discussed considering the long-term radiation and thermal activity of spent nuclear fuel. Notions of physical and chemical barriers to contain nuclear waste are highlighted. A timeframe for nuclear waste disposal is proposed and time-line nuclear waste disposal plan or policy is described and discussed.展开更多
Contamination of soil, water or air, due to a failure of containment or disposal of high level nuclear wastes, can potentially cause serious hazards to the environment or human health. Essential elements of the enviro...Contamination of soil, water or air, due to a failure of containment or disposal of high level nuclear wastes, can potentially cause serious hazards to the environment or human health. Essential elements of the environment and radioactivity dangers to it are illustrated. Issues of high level nuclear waste disposal are discussed with a focus on thermodynamic equilibrium and environment ethics. Major aspects of the issues are analyzed and described briefly to build a perception of risks involved and ethical implications. Nuclear waste containment repository should be as close as possible to thermodynamic equilibrium. A clear demonstration about safety aspects of nuclear waste management is required in gaining public and political confidence in any possible scheme of permanent disposal. Disposal of high level nuclear waste offers a spectrum of environment connected challenges and a long term future of nuclear power depends on the environment friendly solution of the problem of nuclear wastes.展开更多
A fully coupled thermo-hydro-mechano-chemical(THMC) formulation is described in this paper.Special attention is paid to phenomena likely to be encountered in clay barriers used as engineered barriers in the disposal o...A fully coupled thermo-hydro-mechano-chemical(THMC) formulation is described in this paper.Special attention is paid to phenomena likely to be encountered in clay barriers used as engineered barriers in the disposal of nuclear radioactive waste.The types of processes considered in the chemical formulation include hydrolysis,complex formation,oxidation/reduction reactions,acid/base reactions,precipitation/dissolution of minerals and cation exchange.Both kinetics-and equilibrium-controlled reactions are incorporated.The formulation is implemented in a numerical code.An application is presented concerning the performance of a large-scale in-situ heating test simulating high-level radioactive waste repository conditions.展开更多
A compressible nuclear waste disposal contamination in porous media is modeled by a coupled system of partial differential equations. The approximation of this system using a finite element method for the brine, radio...A compressible nuclear waste disposal contamination in porous media is modeled by a coupled system of partial differential equations. The approximation of this system using a finite element method for the brine, radionuclides, and heat combined with a mixed finite element method for the pressure and velocity are analyzed. Optimal order error estimates in H1 and L2 are derived. This paper improves upon previously derived estimates in two aspects. Firstly, the error analysis is given with no restriction on the diffusion tensors. That is, it has included the effects of molecular diffusion and dispersion.Secondly, the "complete compressibility" case is considered.展开更多
In this paper the authors discuss a numerical simulation problem of three-dimensional compressible contamination treatment from nuclear waste. The mathematical model, a nonlinear convection-diffusion system of four PD...In this paper the authors discuss a numerical simulation problem of three-dimensional compressible contamination treatment from nuclear waste. The mathematical model, a nonlinear convection-diffusion system of four PDEs, determines four major physical unknowns: the pressure, the concentrations of brine and radionuclide, and the temperature. The pressure is solved by a conservative mixed finite volume element method, and the computational accuracy is improved for Darcy velocity. Other unknowns are computed by a composite scheme of upwind approximation and mixed finite volume element. Numerical dispersion and nonphysical oscillation are eliminated, and the convection-dominated diffusion problems are solved well with high order computational accuracy. The mixed finite volume element is conservative locally, and get the objective functions and their adjoint vector functions simultaneously. The conservation nature is an important character in numerical simulation of underground fluid. Fractional step difference is introduced to solve the concentrations of radionuclide factors, and the computational work is shortened significantly by decomposing a three-dimensional problem into three successive one-dimensional problems. By the theory and technique of a priori estimates of differential equations, we derive an optimal order estimates in L2norm. Finally, numerical examples show the effectiveness and practicability for some actual problems.展开更多
Blockage in the storage and transportation of waste resin is a difficult problem in the radioactive waste treatment process of nuclear power plants.In this study,in order to solve the problems of unstable resin transp...Blockage in the storage and transportation of waste resin is a difficult problem in the radioactive waste treatment process of nuclear power plants.In this study,in order to solve the problems of unstable resin transport concentration and easy blockage of conveying equipment and pipelines in nuclear power plants in China,a set of non⁃stirring conveying devices is developed,and theoretical calculations,simulation analysis and experimental verification are carried out.By transporting resin using the no stirring conveying device developed in this paper,it is not only to eliminate the risk of blockage and ensure the safety of transportation,but also to adjust the concentration of conveying resin to change the transport efficiency according to the operating conditions.The effective bearing rate of waste resin storage tank can be improved,so that the comprehensive performance of waste resin storage and transportation in nuclear power plants can be greatly improved.展开更多
The high consumption of electricity and issues related to fossil energy have triggered an increase in energy prices and the scarcity of fossil resources.Consequently,many researchers are seeking alternative energy sou...The high consumption of electricity and issues related to fossil energy have triggered an increase in energy prices and the scarcity of fossil resources.Consequently,many researchers are seeking alternative energy sources.One potential technology,the Microbial Fuel Cell(MFC)based on rice,vegetable,and fruit wastes,can convert chemical energy into electrical energy.This study aims to determine the potency of rice,vegetable,and fruit waste assisted by Cu/Mg electrodes as a generator of electricity.The method used was a laboratory experiment,including the following steps:electrode preparation,waste sample preparation,incubation of the waste samples,construction of a reactor using rice,vegetable,and fruit waste as a source of electricity,and testing.The tests included measuring electrical conductivity,electric current,voltage,current density,and power density.Based on the test results,the maximum current and voltage values for the fruit waste samples were 5.53 V and 11.5 mA,respectively,with a current density of 2.300 mA/cm^(2) and a power density of 12.719 mW/cm^(2).The results indicate the potential for a future development.The next step in development involves determining the optimum conditions for utilizing of rice,vegetable,and fruit waste.The results of the electrical conductivity test on rice,vegetable,and fruit waste samples were 1.51,2.88,and 3.98 mS,respectively,with the highest electrical conductivity value found in the fruit waste sample.展开更多
Homeodomains,a 60-amino acid sequence encoded by 180 nucleotides,are highly conserved DNA-binding motifs that are present in a variety of transcription factors in species ranging from yeast to humans.The NKX proteins ...Homeodomains,a 60-amino acid sequence encoded by 180 nucleotides,are highly conserved DNA-binding motifs that are present in a variety of transcription factors in species ranging from yeast to humans.The NKX proteins belong to the homeodomain(HD)-containing transcription factor family.They play vital roles in the regulation of morphogenesis.NKX1-2 is one member of the NKX subfamily.At present,information about its nuclear localization signal(NLS)sequence is limited.We studied the NLS sequence of zebrafish Nkx1.2 by introducing sequence changes such as deletion,mutation,and truncation,and identified an NLS motif(QNRRTKWKKQ)that is localized at the C-terminus of the homeodomain.Moreover,the deletion of two amino acid residues(RR)in this NLS motif prevents Nkx1.2 from entering the nucleus,indicating that the two amino acids are essential for Nkx1.2 nuclear localization.However,the NLS motif alone is unable to target cytoplasmic protein glutathione S-transferase(GST)to the nucleus.An intact homeodomain is necessary for mediating the complete nuclear transport of cytoplasmic protein.Unlike most nuclear import proteins with short NLS sequences,a long NLS is present in zebrafish Nkx1.2.We also demonstrated that the sequences of homeodomain of NKX1.2 are well conserved among different species.This study is informative to verify the function of the NKX1.2 protein.展开更多
The presence of waste tires poses an environmental challenge as they occupy a significant amount of land and are expensive to dispose in landfills.However,reusing waste tires can address this issue when waste tires ar...The presence of waste tires poses an environmental challenge as they occupy a significant amount of land and are expensive to dispose in landfills.However,reusing waste tires can address this issue when waste tires are used in geotechnical applications.To determine the viability of this approach,laboratoryscale tests were conducted to investigate load-bearing capacity of circular footings on sand-tire shred(STS)mixtures with shredded waste tire contents of 5%e15%by weight and three different widths of shreds.The investigation focused on analyzing the thickness of layers composed of STS mixtures,the soil cap,and the impact of geogrids on bearing capacity.The results indicate that a specific mixture of sand and tire shreds provides the highest footing-bearing capacity.In addition,the optimal shred content and size were found to be 10%by weight and 2 cm×10 cm,respectively.Furthermore,for a given tire shred width,a particular length provides the largest bearing capacity.The results agree well with that of previous research conducted by the first author and his colleagues in direct shear and California bearing ratio(CBR)tests.The primary finding of this research is that the use of two-layered STS mixtures reinforced by geogrids significantly enhances the bearing capacity.展开更多
To achieve the resource utilization of solid waste phosphogypsum(PG)and tackle the problem of utilizing potassium feldspar(PF),a coupled synergistic process between PG and PF is proposed in this paper.The study invest...To achieve the resource utilization of solid waste phosphogypsum(PG)and tackle the problem of utilizing potassium feldspar(PF),a coupled synergistic process between PG and PF is proposed in this paper.The study investigates the features of P and F in PG,and explores the decomposition of PF using hydrofluoric acid(HF)in the sulfuric acid system for K leaching and leaching of P and F in PG.The impact factors such as sulfuric acid concentration,reaction temperature,reaction time,material ratio(PG/PF),liquid–solid ratio,PF particle size,and PF calcination temperature on the leaching of P and K is systematically investigated in this paper.The results show that under optimal conditions,the leaching rate of K and P reach more than 93%and 96%,respectively.Kinetics study using shrinking core model(SCM)indicates two significant stages with internal diffusion predominantly controlling the leaching of K.The apparent activation energies of these two stages are 11.92 kJ·mol^(-1)and 11.55 kJ·mol^(-1),respectively.展开更多
基金support provided by the UKRI via Grants No.EP/S036180/1 and EP/T024607/1feasibility study awards to LSBU from the UKRI National Interdisciplinary Circular Economy Hub (EP/V029746/1)+2 种基金Transforming the Foundation Industries:a Network+ (EP/V026402/1)the Hubert Curien Partnership award 2022 from the British Council,Transforming the Partnership award from the Royal Academy of Engineering (TSP1332)the Newton Fellowship award from the Royal Society (NIF\R1\191571).
文摘Sustainable energy sources are an immediate need to cope with the imminent issue of climate change the world is facing today.In particular,the long-lasting miniatured power sources that can supply energy continually to power handheld gadgets,sensors,electronic devices,unmanned airborne vehicles in space and extreme mining are some of the examples where this is an acute need.It is known from basic physics that radioactive materials decay over few years and some nuclear materials have their half-life until thousands of years.The past five decades of research have been spent harnessing the decay energy of the radioactive materials to develop batteries that can last until the radioactive reaction continues.Thus,an emergent opportunity of industrial symbiosis to make use of nuclear waste by using radioactive waste as raw material to develop bat-teries with long shelf life presents a great opportunity for sustainable energy resource development.However,the current canon of research on this topic is scarce.This perspective draws fresh discussions on the topic while highlighting future directions in this wealthy arena of research.Graphical abstract A long-lasting miniaturised nuclear battery utilising 14C radioactive isotope as fuel.
基金This research was supported by the National Key R&D Program of China(No.2018YFC1503200)the Nuclear Waste Geological Disposal Project([2013]727)+2 种基金the National Natural Science Foundation of China(Grant Nos.41790463 and 41730425)the Spark Program of Earthquake Sciences of CEA(XH18063Y)the Special Fund of GEC of CEA(YFGEC2017003,SFGEC2014006).
文摘In order to research whether it is suitable to set a geological disposal repository for high-level radioactive nuclear waste into one target granite body,two active source seismic profles were arranged near a small town named Tamusu,Western China.The study area is with complex surface conditions,thus the seismic exploration encountered a variettraveltimey of technical difculties such as crossing obstacles,de-noising harmful scattered waves,and building complex near-surface velocity models.In order to address those problems,techniques including cross-obstacle seismic geometry design,angle-domain harmful scattered noise removal,and an acoustic wave equation-based inversion method jointly utilizing both the and waveform of frst arrival waves were adopted.The fnal seismic images clearly exhibit the target rock’s unconformable contact boundary and its top interface beneath the sedimentary and weathered layers.On this basis,it could be confrmed that the target rock is not thin or has been transported by geological process from somewhere else,but a native and massive rock.There are a few small size fractures whose space distribution could be revealed by seismic images within the rock.The fractures should be kept away.Based on current research,it could be considered that active source seismic exploration is demanded during the sitting process of the geological disposal repository for nuclear waste.The seismic acquisition and processing techniques proposed in the present paper would ofer a good reference value for similar researches in the future.
基金Funded by the National Natural Science Foundation of China(No.51672228)the Project of State Key Laboratory of Environmentfriendly Energy Materials(Southwest University of Science and Technology,Nos.18fksy0214 and 20fksy11)+1 种基金the Postgraduate Innovation Fund Project by Southwest University of Science and Technology(No.19ycx0016)the Science Development Foundation of China Academy of Engineering Physics。
文摘We reported a rapid synthesis of Sm^(3+)/Zr^(4+)co-doped Gd2Ti2O7 pyrochlore simulated nuclear wastes solidification by self-propagation plus quick pressing technique.With increment excess contents of Sm2O3 and ZrO2 from 0 to 10wt%,the phase composition of the products is a mixed phase of pyrochlore structure and defective fluorite structure by X-ray diffraction(XRD)analysis and Raman spectrum.In addition,the SEM results demonstrate the fracture surface and microstructure of Gd2Ti2O7-based pyrochlore.The densified pyrochlore waste form exhibits high bulk density of 5.56 g·cm^(-3) and vickers hardness of 11.20±0.2 GPa.The leaching tests show that the elemental leaching rates of Gd,Sm,and Cu after 42 days are 1.92×10^(-4),1.51×10^(-4),and 3.90×10^(-3) g·m^(-2)·d^(-1),respectively.
基金part of studies that will be contin-ued within Polish Governmental Project“Technology Supporting Development of Safe Nuclear Power,”Part“Development of Techniques and Technologies Supporting Management of Spent Nuclear Fuel and Radioactive Waste.”
文摘A complex Sol-Gel process has been used for synthesis of silica glasses designed to contain high-level nuclear wastes. Cs, Sr, Co, and Nd (generically denoted Me) were used, the last as surrogate for actinides. Gels in the form of powders and sintered compacts were prepared by hydrolysis and polycondensation of tetraethoxide/Me nitrate solutions, which contained ascorbic acid as a catalyst. Thermal treatment studies were conducted on the resulting gels. Transformation to final products was studied by thermogravimetric analysis, infrared spectroscopy, and X-ray diffraction. Preliminary testing of Me leaching was also completed in quiescent water. Only a single dense form was resistant to
基金Supported by Research Fund for the Doctoral Program of Higher Education of China(No.20120073130009)National Natural Science Foundation of China(No.11175118)Research and innovation project of Shanghai Municipal Education Commission(No.12ZZ022)
文摘The properties of a Lanthanum bromide(LaBr3)detector and its response functions were investigated via experiments and simulations in this paper.The LaBr3detector had good relative energy resolution and higher efficiency than a high-purity germanium detector.Monte Carlo and other numerical methods were used to calculate the efficiencies of a LaBr3detector with a square collimation window.A model of the numerical method was established based on a pure geometric model that was consistent with the experimental situation.The results showed that the detector response functions calculated by these methods were in great agreement with experimental results.
文摘A set of potential parameters for modeling zircon was obtained by atomistic simulation techniques and a reasonable structural model of zircon was established by fitting some important properties of zircon.Based on the equilibrium configuration of zircon, authors calculated the formation energies of basic point defects and intrinsic disorders. The heats of solution of substituting Pu for Zr showed that there was an immiscible gap at the composition of (Pu75%-Zr25%, in mole fraction), which suggests that the amount of Pu substituting for Zr in zircon be≤50%.
基金This work is suported by National Science Foundation
文摘Abstract A system of quasilinear coupled equations which arise from simulation of contamination of geologic nulear waste in porous media is studied. We’ll discuss Galerkin method for the model of compressible flow with molecular diffusion and dispersion. Some new techniques are introcued to error analysis. Only one dimensional case is considered. The optimal error estimate in both L^2 and H^1 is proved. A contribution of this paper is how the dispersion term can be handled,
文摘The main objective of this paper is to analyze the current status of high-level nuclear waste disposal along with presentation of practical perspectives about the environmental issues involved. Present disposal designs and concepts are analyzed on a scientific basis and modifications to existing designs are proposed from the perspective of environmental safety. A new concept of a chemical heat sink is introduced for the removal of heat emitted due to radioactive decay in the spent nuclear fuel or high-level radioactive waste, and thermal spikes produced by radiation in containment materials. Mainly, UO2 and metallic U are used as fuels in nuclear reactors. Spent nuclear fuel contains fission products and transuranium elements which would remain radioactive for 104 to 108years. Essential concepts and engineering strategies for spent nuclear fuel disposal are described. Conceptual designs are described and discussed considering the long-term radiation and thermal activity of spent nuclear fuel. Notions of physical and chemical barriers to contain nuclear waste are highlighted. A timeframe for nuclear waste disposal is proposed and time-line nuclear waste disposal plan or policy is described and discussed.
文摘Contamination of soil, water or air, due to a failure of containment or disposal of high level nuclear wastes, can potentially cause serious hazards to the environment or human health. Essential elements of the environment and radioactivity dangers to it are illustrated. Issues of high level nuclear waste disposal are discussed with a focus on thermodynamic equilibrium and environment ethics. Major aspects of the issues are analyzed and described briefly to build a perception of risks involved and ethical implications. Nuclear waste containment repository should be as close as possible to thermodynamic equilibrium. A clear demonstration about safety aspects of nuclear waste management is required in gaining public and political confidence in any possible scheme of permanent disposal. Disposal of high level nuclear waste offers a spectrum of environment connected challenges and a long term future of nuclear power depends on the environment friendly solution of the problem of nuclear wastes.
基金supported by ENRESA and the European Commissionsupport given by CNPq(Conselho Nacional de Desenvolvimento Cientíco e Tecnológico)and the assistance of the Ministerio de Ciencia y Tecnología of Spain through research grant(BIA2008-06537)
文摘A fully coupled thermo-hydro-mechano-chemical(THMC) formulation is described in this paper.Special attention is paid to phenomena likely to be encountered in clay barriers used as engineered barriers in the disposal of nuclear radioactive waste.The types of processes considered in the chemical formulation include hydrolysis,complex formation,oxidation/reduction reactions,acid/base reactions,precipitation/dissolution of minerals and cation exchange.Both kinetics-and equilibrium-controlled reactions are incorporated.The formulation is implemented in a numerical code.An application is presented concerning the performance of a large-scale in-situ heating test simulating high-level radioactive waste repository conditions.
文摘A compressible nuclear waste disposal contamination in porous media is modeled by a coupled system of partial differential equations. The approximation of this system using a finite element method for the brine, radionuclides, and heat combined with a mixed finite element method for the pressure and velocity are analyzed. Optimal order error estimates in H1 and L2 are derived. This paper improves upon previously derived estimates in two aspects. Firstly, the error analysis is given with no restriction on the diffusion tensors. That is, it has included the effects of molecular diffusion and dispersion.Secondly, the "complete compressibility" case is considered.
基金supported by the Natural Science Foundation of Shangdong Province (Grant No.ZR2021MA019)Natural Science Foundation of Hunan Province (Grant No.2018JJ2028)。
文摘In this paper the authors discuss a numerical simulation problem of three-dimensional compressible contamination treatment from nuclear waste. The mathematical model, a nonlinear convection-diffusion system of four PDEs, determines four major physical unknowns: the pressure, the concentrations of brine and radionuclide, and the temperature. The pressure is solved by a conservative mixed finite volume element method, and the computational accuracy is improved for Darcy velocity. Other unknowns are computed by a composite scheme of upwind approximation and mixed finite volume element. Numerical dispersion and nonphysical oscillation are eliminated, and the convection-dominated diffusion problems are solved well with high order computational accuracy. The mixed finite volume element is conservative locally, and get the objective functions and their adjoint vector functions simultaneously. The conservation nature is an important character in numerical simulation of underground fluid. Fractional step difference is introduced to solve the concentrations of radionuclide factors, and the computational work is shortened significantly by decomposing a three-dimensional problem into three successive one-dimensional problems. By the theory and technique of a priori estimates of differential equations, we derive an optimal order estimates in L2norm. Finally, numerical examples show the effectiveness and practicability for some actual problems.
基金Sponsored by the Independent Scientific Research Fund of China Nuclear Power Engineering Co.,Ltd(Grant No.KY1744).
文摘Blockage in the storage and transportation of waste resin is a difficult problem in the radioactive waste treatment process of nuclear power plants.In this study,in order to solve the problems of unstable resin transport concentration and easy blockage of conveying equipment and pipelines in nuclear power plants in China,a set of non⁃stirring conveying devices is developed,and theoretical calculations,simulation analysis and experimental verification are carried out.By transporting resin using the no stirring conveying device developed in this paper,it is not only to eliminate the risk of blockage and ensure the safety of transportation,but also to adjust the concentration of conveying resin to change the transport efficiency according to the operating conditions.The effective bearing rate of waste resin storage tank can be improved,so that the comprehensive performance of waste resin storage and transportation in nuclear power plants can be greatly improved.
文摘The high consumption of electricity and issues related to fossil energy have triggered an increase in energy prices and the scarcity of fossil resources.Consequently,many researchers are seeking alternative energy sources.One potential technology,the Microbial Fuel Cell(MFC)based on rice,vegetable,and fruit wastes,can convert chemical energy into electrical energy.This study aims to determine the potency of rice,vegetable,and fruit waste assisted by Cu/Mg electrodes as a generator of electricity.The method used was a laboratory experiment,including the following steps:electrode preparation,waste sample preparation,incubation of the waste samples,construction of a reactor using rice,vegetable,and fruit waste as a source of electricity,and testing.The tests included measuring electrical conductivity,electric current,voltage,current density,and power density.Based on the test results,the maximum current and voltage values for the fruit waste samples were 5.53 V and 11.5 mA,respectively,with a current density of 2.300 mA/cm^(2) and a power density of 12.719 mW/cm^(2).The results indicate the potential for a future development.The next step in development involves determining the optimum conditions for utilizing of rice,vegetable,and fruit waste.The results of the electrical conductivity test on rice,vegetable,and fruit waste samples were 1.51,2.88,and 3.98 mS,respectively,with the highest electrical conductivity value found in the fruit waste sample.
基金Supported by the National Natural Science Foundation of China(No.31970429)the Shandong Provincial Natural Science Foundation(No.ZR 2022 MC 032)。
文摘Homeodomains,a 60-amino acid sequence encoded by 180 nucleotides,are highly conserved DNA-binding motifs that are present in a variety of transcription factors in species ranging from yeast to humans.The NKX proteins belong to the homeodomain(HD)-containing transcription factor family.They play vital roles in the regulation of morphogenesis.NKX1-2 is one member of the NKX subfamily.At present,information about its nuclear localization signal(NLS)sequence is limited.We studied the NLS sequence of zebrafish Nkx1.2 by introducing sequence changes such as deletion,mutation,and truncation,and identified an NLS motif(QNRRTKWKKQ)that is localized at the C-terminus of the homeodomain.Moreover,the deletion of two amino acid residues(RR)in this NLS motif prevents Nkx1.2 from entering the nucleus,indicating that the two amino acids are essential for Nkx1.2 nuclear localization.However,the NLS motif alone is unable to target cytoplasmic protein glutathione S-transferase(GST)to the nucleus.An intact homeodomain is necessary for mediating the complete nuclear transport of cytoplasmic protein.Unlike most nuclear import proteins with short NLS sequences,a long NLS is present in zebrafish Nkx1.2.We also demonstrated that the sequences of homeodomain of NKX1.2 are well conserved among different species.This study is informative to verify the function of the NKX1.2 protein.
文摘The presence of waste tires poses an environmental challenge as they occupy a significant amount of land and are expensive to dispose in landfills.However,reusing waste tires can address this issue when waste tires are used in geotechnical applications.To determine the viability of this approach,laboratoryscale tests were conducted to investigate load-bearing capacity of circular footings on sand-tire shred(STS)mixtures with shredded waste tire contents of 5%e15%by weight and three different widths of shreds.The investigation focused on analyzing the thickness of layers composed of STS mixtures,the soil cap,and the impact of geogrids on bearing capacity.The results indicate that a specific mixture of sand and tire shreds provides the highest footing-bearing capacity.In addition,the optimal shred content and size were found to be 10%by weight and 2 cm×10 cm,respectively.Furthermore,for a given tire shred width,a particular length provides the largest bearing capacity.The results agree well with that of previous research conducted by the first author and his colleagues in direct shear and California bearing ratio(CBR)tests.The primary finding of this research is that the use of two-layered STS mixtures reinforced by geogrids significantly enhances the bearing capacity.
基金jointly supported by the National Key Research and Development Program of China (2019YFC1905800)the National Key Research & Development Program of China (2018YFC1903500)+4 种基金the commercial project by Beijing Zhong Dian Hua Yuan Environment Protection Technology Co., Ltd. (E01211200005)the Regional key projects of the science and technology service network program (STS program) of the Chinese Academy of Sciences (KFJ-STS-QYZD-153)the Ningbo Science and Technology Innovation Key Projects (2020Z099, 2022Z028)the Ningbo Municipal Commonweal Key Program (2019C10033)the support of Mineral Resources Analytical and Testing Center, Institute of Process Engineering, Chinese Academy of Science
文摘To achieve the resource utilization of solid waste phosphogypsum(PG)and tackle the problem of utilizing potassium feldspar(PF),a coupled synergistic process between PG and PF is proposed in this paper.The study investigates the features of P and F in PG,and explores the decomposition of PF using hydrofluoric acid(HF)in the sulfuric acid system for K leaching and leaching of P and F in PG.The impact factors such as sulfuric acid concentration,reaction temperature,reaction time,material ratio(PG/PF),liquid–solid ratio,PF particle size,and PF calcination temperature on the leaching of P and K is systematically investigated in this paper.The results show that under optimal conditions,the leaching rate of K and P reach more than 93%and 96%,respectively.Kinetics study using shrinking core model(SCM)indicates two significant stages with internal diffusion predominantly controlling the leaching of K.The apparent activation energies of these two stages are 11.92 kJ·mol^(-1)and 11.55 kJ·mol^(-1),respectively.
