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
This study investigates the use of waste fat biodiesel(WFB)from the leather industry as a substitute for diesel fuel.Specifically,it examines the diesel engine performance of WFB,a blend of WFB and diesel(B50),and dif...This study investigates the use of waste fat biodiesel(WFB)from the leather industry as a substitute for diesel fuel.Specifically,it examines the diesel engine performance of WFB,a blend of WFB and diesel(B50),and different blends of WFB and silicon dioxide(SiO_(2))nanoparticles(B50SiO_(2)40,B50SiO_(2)80,and B50SiO_(2)120μg/g).The results indicate that the B50SiO_(2)120 blend increases brake thermal efficiency by 10.03%compared to pure biodiesel but falls 1.93%short of neat diesel.Furthermore,the B50SiO_(2)120 mixture reduces smoke,hydrocarbon,and carbon monoxide emissions by 31.87%,34.14%,and 43.97%respectively,compared to diesel.However,the B50SiO_(2)120 blend shows a 4.91%increase in nitrogen oxide emissions compared to diesel.展开更多
During the highway construction,a large number of spoil areas will be generated while a large amount of waste slag and soil could not be rationally utilized.Besides,the vegetation recovery is slow in the spoil areas d...During the highway construction,a large number of spoil areas will be generated while a large amount of waste slag and soil could not be rationally utilized.Besides,the vegetation recovery is slow in the spoil areas due to the soil depletion.Aiming at recycling the solid waste,the sieved engineering waste slag with local red clay and corn straw biochar was supplied to solve the problem of insufficient nutrients in engineering waste slag and soil.In addition,planting experiments of alfalfa(Medicago sativa L.)and Amorpha fruticosa L.combined with physical and chemical experiments were carried out to prove the feasibility of the novel improved substrate for the reclamation of spoil areas.The results show that the substrate's improvement effect is mainly affected by the soil to slag ratio and the biochar content.The improvement effect of soil matrix in highway spoil area decreases with the increase of the waste slag content,especially when the soil-slag ratio is less than 3,and the promotion of plants is limited.On the contrary,the improvement effect is proportional to the biochar content(3%-8%).But it is noted that the Cu and Pb in the soil will exceed the clean limit corresponding to the Nemero soil pollution index level when the biochar content is 8%.Therefore,it is recommended that the soil-slag ratio should be≥3,and the biochar content should reach 3%-5%.This research provides experimental basis and technical support for utilizing solid waste resources in the reclamation of highway spoil areas.展开更多
MXene,a transition metal carbide/nitride,has been prominent as an ideal electrochemical active material for supercapacitors.However,the low MXene load limits its practical applications.As environmental concerns and su...MXene,a transition metal carbide/nitride,has been prominent as an ideal electrochemical active material for supercapacitors.However,the low MXene load limits its practical applications.As environmental concerns and sustainable development become more widely recognized,it is necessary to explore a greener and cleaner technology to recycle textile by-products such as cotton.The present study proposes an effective 3D fabrication method that uses MXene to fabricate waste denim felt into ultralight and flexible supercapacitors through needling and carbonization.The 3D structure provided more sites for loading MXene onto Z-directional fiber bundles,resulting in more efficient ion exchange between the electrolyte and electrodes.Furthermore,the carbonization process removed the specific adverse groups in MXenes,further improving the specific capacitance,energy density,power density and electrical conductivity of supercapacitors.The electrodes achieve a maximum specific capacitance of 1748.5 mF cm-2 and demonstrate remarkable cycling stability maintaining more than 94%after 15,000 galvanostatic charge/discharge cycles.Besides,the obtained supercapacitors present a maximum specific capacitance of 577.5 mF cm^(-2),energy density of 80.2μWh cm^(-2)and power density of 3 mW cm^(-2),respectively.The resulting supercapacitors can be used to develop smart wearable power devices such as smartwatches,laying the foundation for a novel strategy of utilizing waste cotton in a high-quality manner.展开更多
Background: Diagnosis of autoimmune diseases (AID) is challenging, due to overlapping features with other non-immune disorders. Anti-nuclear antibodies (ANA) are sensitive screening tests but anti-deoxyribonucleic aci...Background: Diagnosis of autoimmune diseases (AID) is challenging, due to overlapping features with other non-immune disorders. Anti-nuclear antibodies (ANA) are sensitive screening tests but anti-deoxyribonucleic acid-antibody (anti-DNA), and anti-extractable nuclear antigens (anti-ENA) are specific for AIDs. We aimed to look at ANA patterns in our patients and correlated them with anti-ENA for proper interpretation and better patient management cost-effectively. Methods: A retrospective study was conducted over 1 year from January to December 2022 who were tested for ANA at biology medical laboratory of Pasteur Institute of Dakar. Anti-ENA and anti-DNA results were also analyzed for ANA-positive patients. Statistical analysis was performed using STATA 14.0, p Results: 216 patients were analyzed. Women predominated at 79.2% and mean age was 48 years [CI 95%, 46 - 50], with extremes of 10 and 89. Most represented age group was [41 - 60] with 38%. ANA was positive in 27 (12.5%) of patients, 59.2% of whom were strongly positive (titer of 1/1000, 1/3200 or 1/6400). The most common pattern was nuclear speckled, which was found in 77.8% of samples. Anti-ENA and anti-DNA positivity in ANA-positive patients was found respectively in 63% (17/27) and 1.4% (3/27) of the samples analyzed. Most commonly identified anti-ENA was anti-Sm 29.6%, anti-SSA 29.6%, anti-Ro-52 25.9%, anti-RNP 18.5% and anti-SSB 14.8% which was associated with speckled pattern. Association results indicated a significant relationship between both tests and between ANA titer in the anti-ENA- and ANA-positive patients (p 0.001). Conclusions: ANA, Anti-ENA and anti-DNA antibodies are essential for AIDS diagnosis. However, the testing repertoire should follow an algorithm comprising of clinical features, followed by ANA results with nuclear, mitotic, and cytoplasmic patterns, anti-ENA, and anti-DNA for a more meaningful, and cost-effective diagnostic approach.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This study investigates the use of waste fat biodiesel(WFB)from the leather industry as a substitute for diesel fuel.Specifically,it examines the diesel engine performance of WFB,a blend of WFB and diesel(B50),and different blends of WFB and silicon dioxide(SiO_(2))nanoparticles(B50SiO_(2)40,B50SiO_(2)80,and B50SiO_(2)120μg/g).The results indicate that the B50SiO_(2)120 blend increases brake thermal efficiency by 10.03%compared to pure biodiesel but falls 1.93%short of neat diesel.Furthermore,the B50SiO_(2)120 mixture reduces smoke,hydrocarbon,and carbon monoxide emissions by 31.87%,34.14%,and 43.97%respectively,compared to diesel.However,the B50SiO_(2)120 blend shows a 4.91%increase in nitrogen oxide emissions compared to diesel.
基金supported by the National Natural Science Foundation of China(Grant No.52078034).
文摘During the highway construction,a large number of spoil areas will be generated while a large amount of waste slag and soil could not be rationally utilized.Besides,the vegetation recovery is slow in the spoil areas due to the soil depletion.Aiming at recycling the solid waste,the sieved engineering waste slag with local red clay and corn straw biochar was supplied to solve the problem of insufficient nutrients in engineering waste slag and soil.In addition,planting experiments of alfalfa(Medicago sativa L.)and Amorpha fruticosa L.combined with physical and chemical experiments were carried out to prove the feasibility of the novel improved substrate for the reclamation of spoil areas.The results show that the substrate's improvement effect is mainly affected by the soil to slag ratio and the biochar content.The improvement effect of soil matrix in highway spoil area decreases with the increase of the waste slag content,especially when the soil-slag ratio is less than 3,and the promotion of plants is limited.On the contrary,the improvement effect is proportional to the biochar content(3%-8%).But it is noted that the Cu and Pb in the soil will exceed the clean limit corresponding to the Nemero soil pollution index level when the biochar content is 8%.Therefore,it is recommended that the soil-slag ratio should be≥3,and the biochar content should reach 3%-5%.This research provides experimental basis and technical support for utilizing solid waste resources in the reclamation of highway spoil areas.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(Nos.52073224,32201491)the Textile Vision Basic Research Program of China(No.J202110)+3 种基金the Scientific Research Project of Shaanxi Provincial Education Department,China(No.22JC035)the Advanced Manufacturing Technology Program of Xi’an Science and Technology Bureau,China(No.21XJZZ0019)the Research Fund for the Doctoral Program of Xi’an Polytechnic University(No.BS202053)the Youth Innovation Team of Shaanxi Universities and Institute of Flexible electronics and Intelligent Textile.
文摘MXene,a transition metal carbide/nitride,has been prominent as an ideal electrochemical active material for supercapacitors.However,the low MXene load limits its practical applications.As environmental concerns and sustainable development become more widely recognized,it is necessary to explore a greener and cleaner technology to recycle textile by-products such as cotton.The present study proposes an effective 3D fabrication method that uses MXene to fabricate waste denim felt into ultralight and flexible supercapacitors through needling and carbonization.The 3D structure provided more sites for loading MXene onto Z-directional fiber bundles,resulting in more efficient ion exchange between the electrolyte and electrodes.Furthermore,the carbonization process removed the specific adverse groups in MXenes,further improving the specific capacitance,energy density,power density and electrical conductivity of supercapacitors.The electrodes achieve a maximum specific capacitance of 1748.5 mF cm-2 and demonstrate remarkable cycling stability maintaining more than 94%after 15,000 galvanostatic charge/discharge cycles.Besides,the obtained supercapacitors present a maximum specific capacitance of 577.5 mF cm^(-2),energy density of 80.2μWh cm^(-2)and power density of 3 mW cm^(-2),respectively.The resulting supercapacitors can be used to develop smart wearable power devices such as smartwatches,laying the foundation for a novel strategy of utilizing waste cotton in a high-quality manner.
文摘Background: Diagnosis of autoimmune diseases (AID) is challenging, due to overlapping features with other non-immune disorders. Anti-nuclear antibodies (ANA) are sensitive screening tests but anti-deoxyribonucleic acid-antibody (anti-DNA), and anti-extractable nuclear antigens (anti-ENA) are specific for AIDs. We aimed to look at ANA patterns in our patients and correlated them with anti-ENA for proper interpretation and better patient management cost-effectively. Methods: A retrospective study was conducted over 1 year from January to December 2022 who were tested for ANA at biology medical laboratory of Pasteur Institute of Dakar. Anti-ENA and anti-DNA results were also analyzed for ANA-positive patients. Statistical analysis was performed using STATA 14.0, p Results: 216 patients were analyzed. Women predominated at 79.2% and mean age was 48 years [CI 95%, 46 - 50], with extremes of 10 and 89. Most represented age group was [41 - 60] with 38%. ANA was positive in 27 (12.5%) of patients, 59.2% of whom were strongly positive (titer of 1/1000, 1/3200 or 1/6400). The most common pattern was nuclear speckled, which was found in 77.8% of samples. Anti-ENA and anti-DNA positivity in ANA-positive patients was found respectively in 63% (17/27) and 1.4% (3/27) of the samples analyzed. Most commonly identified anti-ENA was anti-Sm 29.6%, anti-SSA 29.6%, anti-Ro-52 25.9%, anti-RNP 18.5% and anti-SSB 14.8% which was associated with speckled pattern. Association results indicated a significant relationship between both tests and between ANA titer in the anti-ENA- and ANA-positive patients (p 0.001). Conclusions: ANA, Anti-ENA and anti-DNA antibodies are essential for AIDS diagnosis. However, the testing repertoire should follow an algorithm comprising of clinical features, followed by ANA results with nuclear, mitotic, and cytoplasmic patterns, anti-ENA, and anti-DNA for a more meaningful, and cost-effective diagnostic approach.
