Soft actuators,capable of producing mechanical work in response to external stimuli,have potential applications in robotics and exoskeletons.However,they face major challenges related to energy supply,especially in lo...Soft actuators,capable of producing mechanical work in response to external stimuli,have potential applications in robotics and exoskeletons.However,they face major challenges related to energy supply,especially in long-distance and miniaturized environments.Fuel-driven actuators offer a promising solution by enabling the conversion of chemical energy into mechanical energy,supporting selfsustaining operations.Chemical energy from fuel can be converted into mechanical energy either directly or indirectly through methods such as electron transfer-induced charge injection,structural changes,fuel-to-electricity conversion,fuel combustioninduced heat,or fuel-induced pneumatic actuation.This paper provides a comprehensive review of recent developments in fuel-powered actuators,covering their fundamental principles,advancements,and challenges.It concludes with an outlook for miniaturized and autonomous robots,highlighting the great potential of integrating fuel-powered actuators.展开更多
Inorganic materials can solve transportable and on-site hydrolytic hydrogen generation issues.CaH_(2)/(Al/Si)composites are preferable due to their notable chemical properties.However,these composites require pretreat...Inorganic materials can solve transportable and on-site hydrolytic hydrogen generation issues.CaH_(2)/(Al/Si)composites are preferable due to their notable chemical properties.However,these composites require pretreatments,an inert environment,and long hours of physical ball milling for high homogeneity and synergistic effects.CaH_(2)also inhibits the hydrolysis reaction by forming its products on the Al/Si surface,which hinders the direct utilization of composites.This work represents the first investigation of NaH-CaH_(2)(Al/Si)fuel composites,which greatly overcome these limitations and can be directly used for on-site hydrogen generation and proton exchange membrane(PEM)fuel cells.The NaH-CaH_(2)(Al/Si)fuel composites were prepared by using a straightforward mixing method with variable composition ratios,showing high H_(2)yield and fuel cell(FC)performance.NaH addition provides the bridge effect,which opens up a new way to enable efficient hydrolysis and greatly enhances the hydrolysis activity of CaH_(2)/(Al/Si)composites.The novel fuel composites(NaH-CaH_(2)/Al)have extraordinary FC performance and a 0.42 W/cm2 peak power density greater than commercial hydrogen generators.It provides high H_(2)yield 84.4%for NaH-CaH_(2)/Al and 82%for NaH-CaH_(2)/Si compared to NaOH-CaH_(2)(Al/Si),NaCl-CaH_(2)(Al/Si),and KCl-CaH_(2)(Al/Si)composites.The NaH bridge effect hinders the direct water contact and stops the formation of Ca(OH)2 around Al/Si,which provides adequate pathways for the CaH_(2)(Al/Si)hydrolysis.The impressive capabilities of novel fuel composites are anticipated to offer practical uses in fuel cells,automobile applications,and portable/on-board H_(2)generation.展开更多
Covalent organic framework ionomers enable synergistic efficient transport of protons and oxygen in medium-temperature proton exchange membrane fuel cells Proton exchange membrane fuel cells(PEMFCs),as clean and effic...Covalent organic framework ionomers enable synergistic efficient transport of protons and oxygen in medium-temperature proton exchange membrane fuel cells Proton exchange membrane fuel cells(PEMFCs),as clean and efficient energy technologies,are constrained in their performance enhancement by the sluggish oxygen reduction reaction(ORR)kinetics at the cathode,anode CO poisoning(e.g.,from methanol crossover)and intricate water management dilemmas[1].展开更多
Biomass-based hydrocarbon fuels,as one of the alternatives to traditional fossil fuels,have attracted considerable attention in the energy field due to their renewability and environmental benefits.This article provid...Biomass-based hydrocarbon fuels,as one of the alternatives to traditional fossil fuels,have attracted considerable attention in the energy field due to their renewability and environmental benefits.This article provides a systematic review of recent research progress in the chemical synthesis of biomass-based hydrocarbon fuels.It outlines the conversion pathways using feedstocks such as lipids,terpenoids,cellulose/hemicellulose,and lignin.Depending on the feedstock,various products with distinct structural characteristics can be prepared through reactions such as cyclization,condensation,and catalytic hydrogenation.Throughout the synthesis process,three key factors play a critical role:efficient catalyst development,production process optimization,and computational-chemistry-based molecular design.Finally,the article discusses future perspectives for biomass-based hydrocarbon fuel synthesis research.展开更多
Proton exchange membrane fuel cells(PEMFCs)are considered as a promising renewable power source.However,the massive commercial application of PEMFCs has been greatly hindered by their high expense and less-satisfied p...Proton exchange membrane fuel cells(PEMFCs)are considered as a promising renewable power source.However,the massive commercial application of PEMFCs has been greatly hindered by their high expense and less-satisfied performance mainly due to the sluggish oxygen reduction reaction(ORR)kinetics even on state-of-the-art Pt catalyst.Octahedral PtNi nanoparticles(oct-PtNi NPs)with excellent ORR activity in a half-cell have been widely studied,while their performance in membrane electrode assembly(MEA)has much less reported.Herein,we investigated the MEA performance using the carbon supported oct-PtNi NPs(oct-PtNi/C)as the cathode catalyst.Under the mild acid washing condition,the surface Ni atoms of oct-PtNi/C were largely removed,and the performance of the MEA using the acid-leaching oct-PtNi/C(PNC-A)as the cathode catalyst was greatly improved.The maximum power density of the MEA reached 1.0 W·cm^(-2) with the cath-ode Pt loading of 0.2 mg·cm^(-2),which is 15%higher than that using Pt/C as the catalyst.After 30k cycles in the accelerated degradation test(ADT),the MEA using PNC-A as the catalyst showed a performance retention of 82%,higher than that of Pt/C(74%).The results reported here verify the possibility of using PNC-A as an advanced cathode catalyst in PEMFCs,thus enhancing the performance of PEMFCs while lowering the amount of expensive Pt.展开更多
Metok,located in Nyingchi,the Xizang Autonomous Region,is known as the last county in China to be connected by road.Poor transportation and limited access to petroleum were two obstacles to its development.As soon as ...Metok,located in Nyingchi,the Xizang Autonomous Region,is known as the last county in China to be connected by road.Poor transportation and limited access to petroleum were two obstacles to its development.As soon as the highway connecting Metok and the outside world was completed in 2014,China National Petroleum Corporation’s(CNPC)first gas station in the county was put into operation,providing the momentum for this"secret land of Lotus"and helping it embark on a journey toward openness and prosperity.展开更多
Photocatalytic fuel cells provide promising opportunities for sustainable wastewater treatment and energy conversion.However,their applications are challenged by the sluggish oxygen reducton reaction(ORR)kinetics at c...Photocatalytic fuel cells provide promising opportunities for sustainable wastewater treatment and energy conversion.However,their applications are challenged by the sluggish oxygen reducton reaction(ORR)kinetics at cathodes owning to the low O_(2) solubility and diffusion rate.Herein,we proposed a photobiocatalytic fuel cell(PBFC) with a novel hybrid biocathode based on artificially engineered algal cells coated by ZIF-8 confined carbon dots/bilirubin oxidase(ZIF-8/CDs/BOD@algae).Microalgae absorbed CO_(2) and provided O_(2) in situ for BOD catalysts.Due to effective absorption of O_(2) by imidazole and confinement of hydrophobic porous ZIF-8,oxygen diffusion has been accelerated in MOF/enzyme systems.Importantly,the introduction of CDs alleviated the poor conductivity of ZIF-8 and improved the electron transfer rate of BOD.Thus,the biocathode exhibited a high current density of 1767 μA/cm^(2),a 2.26-fold increase compared with that of CDs/BOD/algae biocathode.Also,it displayed enduring operational stability for up to 60 h since the firmly wrapped ZIF-8 shells could encapsulate proteins and protect algae from the external stimulation.When coupled with Mo:BiVO_(4) photoanodes,the PBFC exhibited a remarkable power output of 131.8 μW/cm^(2) using tetracycline hydrochloride(TCH) as a fuel and an increased degradation rate of TCH.Therefore,this work not only establishs an effective confinement strategy for enzyme to enrich oxygen,but also unveils new possibilities for modified microalgal cells aiding photoelectrocatalytic systems to recover energy from wastewater treatment.展开更多
Oleaginous yeasts hold significant potential as biodiesel feedstocks as they accumulate high content of lipids with similar fatty acid profiles to those of plant oils.However,the commercialization of yeast lipids is l...Oleaginous yeasts hold significant potential as biodiesel feedstocks as they accumulate high content of lipids with similar fatty acid profiles to those of plant oils.However,the commercialization of yeast lipids is limited by the high cost of nutrients for yeast cultivation.This study aimed to explore the use of agro-industrial carbon wastes as low-cost nutrients and cultivation strategies for promising oleaginous yeasts.Four oleaginous yeasts were screened for their ability to grow on molasses,crude glycerol,and whey lactose.Among the yeast strains and agro-industrial wastes tested,Candida tropicalis X37 and Rhodotorula mucilaginosa G43 grew best on molasses and produced higher lipids than other strains.Both strains grew better when adding ammonium sulfate as a low-cost nitrogen source,but C.tropicalis X37 produced higher lipids when using only molasses.Through the fed-batch cultivation,C.tropicalis X37 could thrive in high molasses concentration and gave higher biomass and lipids than R.mucilaginosa G43.Scaling up in a bioreactor using an aeration rate of 1.0 air volume per liquid volume per minute further increased the production of biomass and lipids by C.tropicalis X37 up to 15.75±0.42 g/L and 6.55±0.35 g/L,respectively.The analysis of prospective fuel properties confirmed that the yeast lipids are suitable as biodiesel feedstocks.These strategies would contribute greatly to supporting green energy supply,sustainable management of wastes,and environmental protection.展开更多
Fire is a fundamental ecological driver shaping natural vegetation patterns.In the semi-arid southern Espinal-Monte ecotone of Argentina,the spatiotemporal patterns of fire occurrence related to and modulated by clima...Fire is a fundamental ecological driver shaping natural vegetation patterns.In the semi-arid southern Espinal-Monte ecotone of Argentina,the spatiotemporal patterns of fire occurrence related to and modulated by climatic gradients and antecedent conditions are not well researched.This study examined fire occurrence in the semi-arid southern Espinal-Monte ecotone(southeastern La Pampa,northeastern Río Negro,and southwestern Buenos Aires with an area of 68×103 km2)of Argentina,a key environmental transition zone with pronounced climatic and vegetation gradients.The objective was to identify the spatiotemporal patterns of fire occurrence and their relationship with climatic variables.Thermal anomaly(TA)data from the MODIS(Moderate Resolution Imaging Spectrometer;MOD14)sensor(November 2000–March 2020)with confidence levels>65.0%were analyzed.Climatic variables(rainfall isohyets and aridity indices)were obtained from the WorldClim datasets,and annual meteorological conditions(rainfall and potential evapotranspiration)were calculated using the climatic research unit(CRU)database.Monthly data and moving averages of rainfall and aridity indices from distinct periods(two and three years preceding fire events)were integrated.Spatial analysis was conducted using kernel density estimation on a 10 km×10 km grid to correlate TA with climatic gradients,while linear regression examined relationships between summer TA and meteorological variables over different periods.Results showed that the highest fire occurrence was recorded in summer,with peaks in December and January.Spatially,55.0%of TA occurred in areas with annual rainfall of 300–400 mm,and 64.5%in areas with an aridity index of 0.3–0.4,forming an arc-like distribution in the center of the ecotone.The highest TA densities were observed in southeastern La Pampa and northeastern Río Negro,decreasing toward southwestern Buenos Aires.Significant correlations(R2>0.700)were found among TA accumulation,aridity index values,and cumulative rainfall from previous two and three years,at both vegetation unit and provincial levels.Summer was the critical season for fire occurrence,with spatial distribution primarily determined by the interaction between climatic conditions and woody biomass availability.The lower fire incidence in southwestern Buenos Aires was linked to sparse woody vegetation and agricultural expansion,which reduced fuel load.These findings reinforce that fuel availability,modulated by climatic conditions from previous years,is a key limiting factor for fire dynamics in this area,and that human activities such as agriculture and grazing alter fire regimes by affecting fuel structure and continuity.展开更多
Microbial contamination and the resulting corrosion in aircraft fuel system pose a serious threat to flight safety.Revealing the corrosion behavior and mechanism of fuel-degrading microorganisms on tank materials is c...Microbial contamination and the resulting corrosion in aircraft fuel system pose a serious threat to flight safety.Revealing the corrosion behavior and mechanism of fuel-degrading microorganisms on tank materials is crucial for developing effective mitigation strategies.In this study,the corrosion mechanisms of two representative hydrocarbon-degrading bacteria,Alcanivorax dieselolei and Microbacterium oxydans,toward AA7075 aluminum alloy,were systematically investigated.A combination of biofilm characterization,electrochemical testing,and surface/corrosion product characterization was employed.Both strains markedly accelerated the corrosion of AA7075,as evidence by the progressive decrease in polarization resistance and the pronounced rightward shift of the potentiodynamic polarization curves.Moreover,the difference between the pitting potential(E_(pit))and the corrosion potential(E_(corr))(ΔE=E_(pit)‒E_(corr))decreased due to microbial activities,indicating a pronounced tendency toward accelerated pitting corrosion.Corrosion morphology analysis revealed that both microbes promoted localized pitting corrosion.Furthermore,analysis of aviation kerosene composition indicated that both bacteria accelerated the degradation of C8 and C9 alkanes.These findings highlight the multiple threats of microbial contamination,material degradation,and fuel quality deterioration in fuel systems and underscore the need for targeted protection strategies for marine aviation operations.展开更多
To ensure the safe transportation of radioactive materials,numerous countries have established specific standards.For the transfer of fissile materials,it is imperative that the material within the packaging remains i...To ensure the safe transportation of radioactive materials,numerous countries have established specific standards.For the transfer of fissile materials,it is imperative that the material within the packaging remains in a subcritical state during routine,normal,and accidental transport conditions.In the event of an accident,the rods within the storage tank may become rearranged,introducing uncertainty that must be accounted for to ensure that criticality analysis results are conservative.Historically,this uncertainty was addressed overly conservatively due to limited research on non-uniform arrangement scenarios,which proved unsuitable for criticality safety analysis of spent fuel packages.This paper introduced three distinct methods to non-uniformly rearrange fuel rods—Uniform Arrangement by Blocks,Layer-by-Layer Determination,and Birdcage Deformation—and meticulously evaluates the influences of rod rearrangement on the effective multiplication factor of neutrons,k eff,utilizing the Monte Carlo method.Ultimately,this study presents a holistic method capable of encompassing the entire spectrum of potential effects stemming from the rearrangement of fuel rods during rods mispositioning accident.By augmenting the safety margin,this approach proves to be adeptly suited for the criticality safety analysis of nuclear fuel transport containers.展开更多
The proton exchange membrane fuel cell(PEMFC)and the hydrogen hybrid power system are studied by the fuzzy-PID(FPID)controlmethod and the fuzzy-PID controlmethod by Artificial Bee Colony algorithm(ABCFPID),respectivel...The proton exchange membrane fuel cell(PEMFC)and the hydrogen hybrid power system are studied by the fuzzy-PID(FPID)controlmethod and the fuzzy-PID controlmethod by Artificial Bee Colony algorithm(ABCFPID),respectively.The results reveal that compared with the FPID control method,the temperature overshoot of the PEMFC stack under the ABC-FPID control method is decreased by 0.6%.Moreover,the circulating water flow rate within the full operating envelope(about 3 min)is reduced by 19.46 L,which means the ABC-FPID control method is more effective in regulating the stack temperature.Then,the ABC-FPID control method is proposed to study the hydrogen hybrid power system,and the system output power matching,operating characteristic curve of the fuel cell,state of charge(SOC)of the lithium battery,system efficiency and hydrogen demand are obtained.The results indicate that the maximum system efficiency reaches 46.3%,the average system efficiency is 33.8%,and the average hydrogen demand is 0.192 kg/s.Overall,the ABC-FPID control method can efficiently ensure the stability of the fuel cell’s output power,and actively prompt the lithium battery to fulfill the function of“peak shaving and valley filling”under variable load power conditions.展开更多
Despite significant progress in fuel cell technology,its large-scale industrial application is still challenged by the frequently encountered performance failure during long-term operation.Clarifying the failure mecha...Despite significant progress in fuel cell technology,its large-scale industrial application is still challenged by the frequently encountered performance failure during long-term operation.Clarifying the failure mechanism is the key to extending the lifecycle and enhancing stability.Herein,we have developed a time and space resolved multi-field characterization,including electrochemical impedance spectroscopy,to unveil its underlying mechanism.With this operando and non-destructive characterization,the dynamic evolution of the internal mass transport,heat,and electricity field distribution is fully depicted within an industrial-scale fuel cell in operation.Thus,it is revealed that hydrogen starvation occurs in the outlet region due to the excessive hydrogen consumption during the loading-down process.This can induce local low current density and carbon corrosion,which may subsequently cause severe damage to the structure of the catalyst layer and membrane,ultimately leading to performance failure.With this understanding,we further identify a descriptor for early diagnosis to prevent any potential degradation.The methodology is of significance,which can bring fuel cell technology a step further towards industrial applications.展开更多
This study focused on improving the cathode performance of Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.15)O_(3-δ)(BSCN)-based perovskite materials through molybdenum(Mo)doping.Pure BSCN and Mo-modified-BSCN—Ea_(0.6)Sr_(0.4)Co_(0...This study focused on improving the cathode performance of Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.15)O_(3-δ)(BSCN)-based perovskite materials through molybdenum(Mo)doping.Pure BSCN and Mo-modified-BSCN—Ea_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.1)Mo_(0.05)O_(3-δ)(B S CNM_(0.05)),Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.05)Mo_(0.1)O_(3-δ)(BSCNM_(0.1)),and Ba_(0.6)Sr_(0.4)Co_(0.85)Mo_(0.15)O_(3-δ)(BSCM)—with Mo doping contents of 5mol%,10mol%,and15mol%,respectively,were successfully prepared using the sol-gel method.The effects of Mo doping on the crystal structure,conductivity,thermal expansion coefficient,oxygen reduction reaction(ORR)activity,and electrochemical performance were systematically evaluated using X-ray diffraction analysis,thermally induced characterization,electrochemical impedance spectroscopy,and single-cell performance tests.The results revealed that Mo doping could improve the conductivity of the materials,suppress their thermal expansion effects,and significantly improve the electrochemical performance.Surface chemical state analysis using X-ray photoelectron spectroscopy revealed that 5mol%Mo doping could facilitate a high adsorbed oxygen concentration leading to enhanced ORR activity in the materials.Density functional theory calculations confirmed that Mo doping promoted the ORR activity in the materials.At an operating temperature of 600℃,the BSCNM_(0.05)cathode material exhibited significantly enhanced electrochemical impedance characteristics,with a reduced area specific resistance of 0.048Ω·cm~2,which was lower than that of the undoped BSCN matrix material by 32.39%.At the same operating temperature,an anode-supported single cell using a BSCNM_(0.05)cathode achieved a peak power density of 1477 mW·cm^(-2),which was 30.71%,56.30%,and 171.50%higher than those of BSCN,BSCNM_(0.1),and B SCM,respectively.The improved ORR activity and electrochemical performance of BSCNM_(0.05)indicate that it can be used as a cathode material in low-temperature solid oxide fuel cells.展开更多
Proton exchange membranes(PEMs)play a central role in determining the efficiency,durability,and operational flexibility of PEM fuel cells(PEMFCs).However,conventional PEMs exhibit strong temperature-dependent proton-t...Proton exchange membranes(PEMs)play a central role in determining the efficiency,durability,and operational flexibility of PEM fuel cells(PEMFCs).However,conventional PEMs exhibit strong temperature-dependent proton-transport behavior,which limits their ability to support both rapid start-up at low temperatures and stable operation at elevated temperatures.Water-mediated PEMs show excellent conductivity under low-temperature and high-humidity conditions but suffer from dehydration and structural instability in the high-temperature regime.In contrast,water-independent PEMs,particularly phosphoric-acid-doped systems,conduct protons efficiently under anhydrous high-temperature conditions yet experience acid leaching that hampers room-temperature start-up and long-term durability.This review summarizes the fundamental proton-transport mechanisms that govern temperature-dependent performance and discusses recent advances in materials design aimed at enabling wide-temperature-range PEM operation.For water-mediated membranes,strategies such as incorporating hydrophilic fillers,constructing confined hydrophilic domains,and introducing additional proton-transfer sites have been developed to mitigate water loss and stabilize proton conduction.For water-independent membranes,approaches including strengthening polymer–acid interactions,engineering nanoscale confinement,designing multilayer architectures,and constructing multi–proton-carrier networks effectively improve acid retention and broaden operational temperature windows.Emerging fixed-carrier systems based on phosphonic-acid-grafted polymers,metal–organic frameworks,and covalent organic frameworks offer new pathways for stable anhydrous proton conduction across a wide temperature range.We conclude by outlining key challenges and future research opportunities,including reducing the dependence on volatile or leachable proton carriers,developing adaptive nanochannel architectures,improving anhydrous high-temperature conduction,and establishing scalable membrane fabrication methods.Continued innovation in these directions is expected to enable next-generation wide-temperature-range PEMs capable of flexible,high-efficiency operation from sub-zero to high-temperature conditions.展开更多
One of the main issues in designing optimum tapered cascades for uranium enrichment for annual fuel production in a power reactor is whether to employ large(fat)or small(thin)cascades.What will be the permissible and ...One of the main issues in designing optimum tapered cascades for uranium enrichment for annual fuel production in a power reactor is whether to employ large(fat)or small(thin)cascades.What will be the permissible and optimal ranges of the number of machines that can be used in a cascade?For the first time,the permissible and optimal ranges of the number of gas centrifuges that can be utilized in a cascade were investigated using two types of centrifuges,and the performance of small and large tapered cascades was discussed.The particle swarm optimization algorithm(PSO)has been used to optimize tapered cascades.The results show:(1)For the first centrifuge,41 cascades(91≤n≤4897)and for the second centrifuge,49 cascades(18≤n≤3839)with small and large sizes can be used in enrichment facilities,and the best cascade for them has 530(with 23 stages)and 39(with 7 stages)centrifuges,respectively.(2)For both centrifuges,when 600≤n(number of centrifuges=n),the large cascade performance changes are relatively insignificant.(3)For both types of gas centrifuges,the annual los s of separation power in enrichment facilities is approximately 1.25%-4.82%of the total separation work required.展开更多
BACKGROUND Solid fuel use for cooking and heating is a major environmental risk factor,yet its association with new-onset heart disease(HD)remains unclear.The aim of this study was to investigate the relationship betw...BACKGROUND Solid fuel use for cooking and heating is a major environmental risk factor,yet its association with new-onset heart disease(HD)remains unclear.The aim of this study was to investigate the relationship between solid fuel exposure and new-onset HD in a large cohort.METHODS Multivariable logistic regression models assessed associations between cooking/heating fuel types(coal,crop residue/wood,liquefied petroleum gas,natural gas,and others)and new-onset HD.Subgroup analyses explored effect modification by age,sex,education,smoking,alcohol use,and region.RESULTS A prospective cohort study included 5915 participants,with 781 participants(13.2%)developing new-onset HD.Coal use for cooking showed an initial association with new-onset HD risk(OR=1.41,95%CI:1.06–1.86,P=0.02),which attenuated after full adjustment(OR=1.28,95%CI:0.96–1.72,P=0.10).Coal use for heating demonstrated robust associations across all models(OR=1.86,95%CI:1.42–2.43,P<0.001).Crop residue/wood burning for heating was also significant(Model 2:OR=1.40,95%CI:1.06–1.86,P=0.02).Subgroup analyses revealed stronger associations among females,non-smokers,non-drinkers,and less-educated participants.Geographic stratification showed significant associations in southern but not northern regions.CONCLUSIONS Solid fuel use,particularly coal for heating,is associated with increased new-onset HD risk.Reducing solid fuel exposure is crucial for HD prevention in low-resource settings.展开更多
Subcritical reactors(SCRs)or subcritical assemblies(SCAs)are the main infrastructure for designing power reactors.These reactors are widely used for training and research because of their high level of inherent safety...Subcritical reactors(SCRs)or subcritical assemblies(SCAs)are the main infrastructure for designing power reactors.These reactors are widely used for training and research because of their high level of inherent safety.The objective of this study is to design a subcritical reactor using a pressurized water reactor(PWR)conventional fuel following two safety points.In the first approach,deeply placed SCR cores with an infinite multiplication factor(k_(∞))of less than unity were identified using the DRAGON lattice code.In the second approach,subcritical reactor cores with an effective multiplication factor(k_(eff))of less than unity were determined by coupling the cell calculations of the DRAGON lattice code and core calculations of the DONJON code.For the deeply subcritical reactor design,it was found that the reactor would remain inherently subcritical while using fuel rods with ^(235)U enrichment of up to 0.9%,regardless of the pitch of the fuel rods.In the second approach,the optimal pitches(1.3 to 2.3 cm)were determined for different fuel enrichment values from 1 to 5%.Subsequently,the k_(eff) was obtained for a fuel rod arrangement of 8×8 to 80×80,and the states in which the reactor would be subcritical were determined for different fuel enrichments at the corresponding optimal pitch.To validate the models used in the DRAGON and DONJON codes,the k_(eff) of the Isfahan Light Water Subcritical Reactor(LWSCR)was experimentally measured and compared with the results of the calculations.Finally,the effects of fuel and moderator temperature changes were investigated to ensure that the designed assemblies remained in the subcritical state at all operational temperatures.展开更多
To address the challenges of high energy consumption and prominent costs in the traditional three-columns distillation process for cellulosic fuel ethanol,a distillation–molecular sieve coupling separation process is...To address the challenges of high energy consumption and prominent costs in the traditional three-columns distillation process for cellulosic fuel ethanol,a distillation–molecular sieve coupling separation process is proposed.This process integrates a three-column(crude distillation column,first distillation column,second distillation column)system with a 3A molecular sieve adsorption deep dehydration unit.A thermal coupling network is constructed via differential pressure design(steam from medium/high-pressure columns as mutual heat sources,reboiler liquid waste heat for feed preheating),and molecular sieve adsorption conditions are optimized.The study first performs a thermodynamic consistency test on the ethanol–water system,determines optimal non-random two-liquid(NRTL)model binary interaction parameters via experimental data regression for Aspen Plus simulation.Aiming at minimum total annual cost(TAC),Aspen Plus is used to optimize process parameters(theoretical tray number,feed location,reflux ratio,side-draw position,etc.).Economic analysis shows this process reduces CO_(2) emission costs by 27.56%,TAC by 15.58%(to 5.123×10^(6) USD·a^(−1)),and increases ethanol purity to>99.6%,providing an effective solution for green,efficient separation.展开更多
Anion exchange membrane fuel cells(AEMFCs),regarded as a promising alternative to proton exchange membrane fuel cells(PEMFCs),have garnered increasing attention because of their cost-effectiveness by using the non-nob...Anion exchange membrane fuel cells(AEMFCs),regarded as a promising alternative to proton exchange membrane fuel cells(PEMFCs),have garnered increasing attention because of their cost-effectiveness by using the non-noble metal catalysts and hydrocarbon-based ionomers as membrane[1].However,despite of extensive researches on non-noble metal catalysts such as Co[2].展开更多
基金Financial support from the program of the National Natural Science Foundation of China(Grant no.52475059)Major Program of National Natural Science Founda-tion of China(NSFC)for Basic Theory and Key Technology of Tri-Co Robots(92248301)+3 种基金the Postdoctoral Research Foundation of China(No.2024M751167)the Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)Jiangsu Province Natural Science Foundation(No.BK20240155)supported by the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Science and ICT(RS2024-00406534,RS-2025-25442809)。
文摘Soft actuators,capable of producing mechanical work in response to external stimuli,have potential applications in robotics and exoskeletons.However,they face major challenges related to energy supply,especially in long-distance and miniaturized environments.Fuel-driven actuators offer a promising solution by enabling the conversion of chemical energy into mechanical energy,supporting selfsustaining operations.Chemical energy from fuel can be converted into mechanical energy either directly or indirectly through methods such as electron transfer-induced charge injection,structural changes,fuel-to-electricity conversion,fuel combustioninduced heat,or fuel-induced pneumatic actuation.This paper provides a comprehensive review of recent developments in fuel-powered actuators,covering their fundamental principles,advancements,and challenges.It concludes with an outlook for miniaturized and autonomous robots,highlighting the great potential of integrating fuel-powered actuators.
基金financial support granted by the National Natural Science Foundation of China (No. 22402225)the Gusu Innovation and Entrepreneurship Leading Talent Plan(No. ZXL2023193)+2 种基金the Sinano Talents Plan (No. 2022000175)the Guangdong Basic and Applied Basic Research Foundation (No.2023A1515111133)the ANSO Scholarship for Young Talents
文摘Inorganic materials can solve transportable and on-site hydrolytic hydrogen generation issues.CaH_(2)/(Al/Si)composites are preferable due to their notable chemical properties.However,these composites require pretreatments,an inert environment,and long hours of physical ball milling for high homogeneity and synergistic effects.CaH_(2)also inhibits the hydrolysis reaction by forming its products on the Al/Si surface,which hinders the direct utilization of composites.This work represents the first investigation of NaH-CaH_(2)(Al/Si)fuel composites,which greatly overcome these limitations and can be directly used for on-site hydrogen generation and proton exchange membrane(PEM)fuel cells.The NaH-CaH_(2)(Al/Si)fuel composites were prepared by using a straightforward mixing method with variable composition ratios,showing high H_(2)yield and fuel cell(FC)performance.NaH addition provides the bridge effect,which opens up a new way to enable efficient hydrolysis and greatly enhances the hydrolysis activity of CaH_(2)/(Al/Si)composites.The novel fuel composites(NaH-CaH_(2)/Al)have extraordinary FC performance and a 0.42 W/cm2 peak power density greater than commercial hydrogen generators.It provides high H_(2)yield 84.4%for NaH-CaH_(2)/Al and 82%for NaH-CaH_(2)/Si compared to NaOH-CaH_(2)(Al/Si),NaCl-CaH_(2)(Al/Si),and KCl-CaH_(2)(Al/Si)composites.The NaH bridge effect hinders the direct water contact and stops the formation of Ca(OH)2 around Al/Si,which provides adequate pathways for the CaH_(2)(Al/Si)hydrolysis.The impressive capabilities of novel fuel composites are anticipated to offer practical uses in fuel cells,automobile applications,and portable/on-board H_(2)generation.
文摘Covalent organic framework ionomers enable synergistic efficient transport of protons and oxygen in medium-temperature proton exchange membrane fuel cells Proton exchange membrane fuel cells(PEMFCs),as clean and efficient energy technologies,are constrained in their performance enhancement by the sluggish oxygen reduction reaction(ORR)kinetics at the cathode,anode CO poisoning(e.g.,from methanol crossover)and intricate water management dilemmas[1].
基金Support by National Natural Science Foundation of China(22127802,22573091)the HY Action(62402010305)。
文摘Biomass-based hydrocarbon fuels,as one of the alternatives to traditional fossil fuels,have attracted considerable attention in the energy field due to their renewability and environmental benefits.This article provides a systematic review of recent research progress in the chemical synthesis of biomass-based hydrocarbon fuels.It outlines the conversion pathways using feedstocks such as lipids,terpenoids,cellulose/hemicellulose,and lignin.Depending on the feedstock,various products with distinct structural characteristics can be prepared through reactions such as cyclization,condensation,and catalytic hydrogenation.Throughout the synthesis process,three key factors play a critical role:efficient catalyst development,production process optimization,and computational-chemistry-based molecular design.Finally,the article discusses future perspectives for biomass-based hydrocarbon fuel synthesis research.
基金supported by grants from the Natural Science Foundation of China(22362031 and 21805121)the Science and Technology Project of Yunnan Province(2019FD137)。
文摘Proton exchange membrane fuel cells(PEMFCs)are considered as a promising renewable power source.However,the massive commercial application of PEMFCs has been greatly hindered by their high expense and less-satisfied performance mainly due to the sluggish oxygen reduction reaction(ORR)kinetics even on state-of-the-art Pt catalyst.Octahedral PtNi nanoparticles(oct-PtNi NPs)with excellent ORR activity in a half-cell have been widely studied,while their performance in membrane electrode assembly(MEA)has much less reported.Herein,we investigated the MEA performance using the carbon supported oct-PtNi NPs(oct-PtNi/C)as the cathode catalyst.Under the mild acid washing condition,the surface Ni atoms of oct-PtNi/C were largely removed,and the performance of the MEA using the acid-leaching oct-PtNi/C(PNC-A)as the cathode catalyst was greatly improved.The maximum power density of the MEA reached 1.0 W·cm^(-2) with the cath-ode Pt loading of 0.2 mg·cm^(-2),which is 15%higher than that using Pt/C as the catalyst.After 30k cycles in the accelerated degradation test(ADT),the MEA using PNC-A as the catalyst showed a performance retention of 82%,higher than that of Pt/C(74%).The results reported here verify the possibility of using PNC-A as an advanced cathode catalyst in PEMFCs,thus enhancing the performance of PEMFCs while lowering the amount of expensive Pt.
文摘Metok,located in Nyingchi,the Xizang Autonomous Region,is known as the last county in China to be connected by road.Poor transportation and limited access to petroleum were two obstacles to its development.As soon as the highway connecting Metok and the outside world was completed in 2014,China National Petroleum Corporation’s(CNPC)first gas station in the county was put into operation,providing the momentum for this"secret land of Lotus"and helping it embark on a journey toward openness and prosperity.
基金support from National Natural Science Foundation of China (Nos.22176086,52100014)Natural Science Foundation of Jiangsu Province (No.BK20210189)+7 种基金State Key laboratory of Pollution Control and Resource Reuse,the Fundamental Research Funds for the Central Universities (Nos.021114380183,021114380189,021114380199)the Research Funds from Frontiers Science Center for Critical Earth Material Cycling of Nanjing UniversityResearch Funds for Jiangsu Distinguished ProfessorCarbon Peaking and Carbon Neutrality Technological Innovation Foundation of Jiangsu Province (No.BE2022861)the Central Universities - Cemac “Geo X” Interdisciplinary Program (No.021114380217)Frontiers Science Center for Critical Earth Material Cycling of Nanjing University (No.2024QNXZ07)Postdoctoral Fellowship Program of CPSF (No.GZC20231105)the Jiangsu Funding Program for Excellent Postdoctoral Talent (No.2023ZB226)。
文摘Photocatalytic fuel cells provide promising opportunities for sustainable wastewater treatment and energy conversion.However,their applications are challenged by the sluggish oxygen reducton reaction(ORR)kinetics at cathodes owning to the low O_(2) solubility and diffusion rate.Herein,we proposed a photobiocatalytic fuel cell(PBFC) with a novel hybrid biocathode based on artificially engineered algal cells coated by ZIF-8 confined carbon dots/bilirubin oxidase(ZIF-8/CDs/BOD@algae).Microalgae absorbed CO_(2) and provided O_(2) in situ for BOD catalysts.Due to effective absorption of O_(2) by imidazole and confinement of hydrophobic porous ZIF-8,oxygen diffusion has been accelerated in MOF/enzyme systems.Importantly,the introduction of CDs alleviated the poor conductivity of ZIF-8 and improved the electron transfer rate of BOD.Thus,the biocathode exhibited a high current density of 1767 μA/cm^(2),a 2.26-fold increase compared with that of CDs/BOD/algae biocathode.Also,it displayed enduring operational stability for up to 60 h since the firmly wrapped ZIF-8 shells could encapsulate proteins and protect algae from the external stimulation.When coupled with Mo:BiVO_(4) photoanodes,the PBFC exhibited a remarkable power output of 131.8 μW/cm^(2) using tetracycline hydrochloride(TCH) as a fuel and an increased degradation rate of TCH.Therefore,this work not only establishs an effective confinement strategy for enzyme to enrich oxygen,but also unveils new possibilities for modified microalgal cells aiding photoelectrocatalytic systems to recover energy from wastewater treatment.
基金supported by Faculty of Agro-Industry and National Science,Research and Innovation Fund(NSRF)and Prince of Songkla University(Ref.No.AGR6701270b)National Research Council of Thailand(NRCT):Contract number N42A680491.
文摘Oleaginous yeasts hold significant potential as biodiesel feedstocks as they accumulate high content of lipids with similar fatty acid profiles to those of plant oils.However,the commercialization of yeast lipids is limited by the high cost of nutrients for yeast cultivation.This study aimed to explore the use of agro-industrial carbon wastes as low-cost nutrients and cultivation strategies for promising oleaginous yeasts.Four oleaginous yeasts were screened for their ability to grow on molasses,crude glycerol,and whey lactose.Among the yeast strains and agro-industrial wastes tested,Candida tropicalis X37 and Rhodotorula mucilaginosa G43 grew best on molasses and produced higher lipids than other strains.Both strains grew better when adding ammonium sulfate as a low-cost nitrogen source,but C.tropicalis X37 produced higher lipids when using only molasses.Through the fed-batch cultivation,C.tropicalis X37 could thrive in high molasses concentration and gave higher biomass and lipids than R.mucilaginosa G43.Scaling up in a bioreactor using an aeration rate of 1.0 air volume per liquid volume per minute further increased the production of biomass and lipids by C.tropicalis X37 up to 15.75±0.42 g/L and 6.55±0.35 g/L,respectively.The analysis of prospective fuel properties confirmed that the yeast lipids are suitable as biodiesel feedstocks.These strategies would contribute greatly to supporting green energy supply,sustainable management of wastes,and environmental protection.
基金funded by the National University of Río Negro Research Project (40-C-658)
文摘Fire is a fundamental ecological driver shaping natural vegetation patterns.In the semi-arid southern Espinal-Monte ecotone of Argentina,the spatiotemporal patterns of fire occurrence related to and modulated by climatic gradients and antecedent conditions are not well researched.This study examined fire occurrence in the semi-arid southern Espinal-Monte ecotone(southeastern La Pampa,northeastern Río Negro,and southwestern Buenos Aires with an area of 68×103 km2)of Argentina,a key environmental transition zone with pronounced climatic and vegetation gradients.The objective was to identify the spatiotemporal patterns of fire occurrence and their relationship with climatic variables.Thermal anomaly(TA)data from the MODIS(Moderate Resolution Imaging Spectrometer;MOD14)sensor(November 2000–March 2020)with confidence levels>65.0%were analyzed.Climatic variables(rainfall isohyets and aridity indices)were obtained from the WorldClim datasets,and annual meteorological conditions(rainfall and potential evapotranspiration)were calculated using the climatic research unit(CRU)database.Monthly data and moving averages of rainfall and aridity indices from distinct periods(two and three years preceding fire events)were integrated.Spatial analysis was conducted using kernel density estimation on a 10 km×10 km grid to correlate TA with climatic gradients,while linear regression examined relationships between summer TA and meteorological variables over different periods.Results showed that the highest fire occurrence was recorded in summer,with peaks in December and January.Spatially,55.0%of TA occurred in areas with annual rainfall of 300–400 mm,and 64.5%in areas with an aridity index of 0.3–0.4,forming an arc-like distribution in the center of the ecotone.The highest TA densities were observed in southeastern La Pampa and northeastern Río Negro,decreasing toward southwestern Buenos Aires.Significant correlations(R2>0.700)were found among TA accumulation,aridity index values,and cumulative rainfall from previous two and three years,at both vegetation unit and provincial levels.Summer was the critical season for fire occurrence,with spatial distribution primarily determined by the interaction between climatic conditions and woody biomass availability.The lower fire incidence in southwestern Buenos Aires was linked to sparse woody vegetation and agricultural expansion,which reduced fuel load.These findings reinforce that fuel availability,modulated by climatic conditions from previous years,is a key limiting factor for fire dynamics in this area,and that human activities such as agriculture and grazing alter fire regimes by affecting fuel structure and continuity.
基金financially supported by the National Natural Science Foundation of China (No. 52371056)the Liaoning Provincial Youth Science Fund Project, China (Category B, No. 2025JH6/101000010)+1 种基金the Guangdong Basic and Applied Basic Research Foundation, China (No. 2024A1515240055)funding from the China Scholarship Council
文摘Microbial contamination and the resulting corrosion in aircraft fuel system pose a serious threat to flight safety.Revealing the corrosion behavior and mechanism of fuel-degrading microorganisms on tank materials is crucial for developing effective mitigation strategies.In this study,the corrosion mechanisms of two representative hydrocarbon-degrading bacteria,Alcanivorax dieselolei and Microbacterium oxydans,toward AA7075 aluminum alloy,were systematically investigated.A combination of biofilm characterization,electrochemical testing,and surface/corrosion product characterization was employed.Both strains markedly accelerated the corrosion of AA7075,as evidence by the progressive decrease in polarization resistance and the pronounced rightward shift of the potentiodynamic polarization curves.Moreover,the difference between the pitting potential(E_(pit))and the corrosion potential(E_(corr))(ΔE=E_(pit)‒E_(corr))decreased due to microbial activities,indicating a pronounced tendency toward accelerated pitting corrosion.Corrosion morphology analysis revealed that both microbes promoted localized pitting corrosion.Furthermore,analysis of aviation kerosene composition indicated that both bacteria accelerated the degradation of C8 and C9 alkanes.These findings highlight the multiple threats of microbial contamination,material degradation,and fuel quality deterioration in fuel systems and underscore the need for targeted protection strategies for marine aviation operations.
文摘To ensure the safe transportation of radioactive materials,numerous countries have established specific standards.For the transfer of fissile materials,it is imperative that the material within the packaging remains in a subcritical state during routine,normal,and accidental transport conditions.In the event of an accident,the rods within the storage tank may become rearranged,introducing uncertainty that must be accounted for to ensure that criticality analysis results are conservative.Historically,this uncertainty was addressed overly conservatively due to limited research on non-uniform arrangement scenarios,which proved unsuitable for criticality safety analysis of spent fuel packages.This paper introduced three distinct methods to non-uniformly rearrange fuel rods—Uniform Arrangement by Blocks,Layer-by-Layer Determination,and Birdcage Deformation—and meticulously evaluates the influences of rod rearrangement on the effective multiplication factor of neutrons,k eff,utilizing the Monte Carlo method.Ultimately,this study presents a holistic method capable of encompassing the entire spectrum of potential effects stemming from the rearrangement of fuel rods during rods mispositioning accident.By augmenting the safety margin,this approach proves to be adeptly suited for the criticality safety analysis of nuclear fuel transport containers.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20231445)Aeronautical Science Foundation of China(20230028052001).
文摘The proton exchange membrane fuel cell(PEMFC)and the hydrogen hybrid power system are studied by the fuzzy-PID(FPID)controlmethod and the fuzzy-PID controlmethod by Artificial Bee Colony algorithm(ABCFPID),respectively.The results reveal that compared with the FPID control method,the temperature overshoot of the PEMFC stack under the ABC-FPID control method is decreased by 0.6%.Moreover,the circulating water flow rate within the full operating envelope(about 3 min)is reduced by 19.46 L,which means the ABC-FPID control method is more effective in regulating the stack temperature.Then,the ABC-FPID control method is proposed to study the hydrogen hybrid power system,and the system output power matching,operating characteristic curve of the fuel cell,state of charge(SOC)of the lithium battery,system efficiency and hydrogen demand are obtained.The results indicate that the maximum system efficiency reaches 46.3%,the average system efficiency is 33.8%,and the average hydrogen demand is 0.192 kg/s.Overall,the ABC-FPID control method can efficiently ensure the stability of the fuel cell’s output power,and actively prompt the lithium battery to fulfill the function of“peak shaving and valley filling”under variable load power conditions.
基金supported by the National Key R&D Program of China[2023YFB4006100]。
文摘Despite significant progress in fuel cell technology,its large-scale industrial application is still challenged by the frequently encountered performance failure during long-term operation.Clarifying the failure mechanism is the key to extending the lifecycle and enhancing stability.Herein,we have developed a time and space resolved multi-field characterization,including electrochemical impedance spectroscopy,to unveil its underlying mechanism.With this operando and non-destructive characterization,the dynamic evolution of the internal mass transport,heat,and electricity field distribution is fully depicted within an industrial-scale fuel cell in operation.Thus,it is revealed that hydrogen starvation occurs in the outlet region due to the excessive hydrogen consumption during the loading-down process.This can induce local low current density and carbon corrosion,which may subsequently cause severe damage to the structure of the catalyst layer and membrane,ultimately leading to performance failure.With this understanding,we further identify a descriptor for early diagnosis to prevent any potential degradation.The methodology is of significance,which can bring fuel cell technology a step further towards industrial applications.
基金financially supported by the National Natural Science Foundation of China(No.22309067)the Open Project Program of the State Key Laboratory of Materials-Oriented Chemical Engineering,China(No.KL21-05)the Marine Equipment and Technology Institute,Jiangsu University of Science and Technology,China(No.XTCX202404)。
文摘This study focused on improving the cathode performance of Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.15)O_(3-δ)(BSCN)-based perovskite materials through molybdenum(Mo)doping.Pure BSCN and Mo-modified-BSCN—Ea_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.1)Mo_(0.05)O_(3-δ)(B S CNM_(0.05)),Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.05)Mo_(0.1)O_(3-δ)(BSCNM_(0.1)),and Ba_(0.6)Sr_(0.4)Co_(0.85)Mo_(0.15)O_(3-δ)(BSCM)—with Mo doping contents of 5mol%,10mol%,and15mol%,respectively,were successfully prepared using the sol-gel method.The effects of Mo doping on the crystal structure,conductivity,thermal expansion coefficient,oxygen reduction reaction(ORR)activity,and electrochemical performance were systematically evaluated using X-ray diffraction analysis,thermally induced characterization,electrochemical impedance spectroscopy,and single-cell performance tests.The results revealed that Mo doping could improve the conductivity of the materials,suppress their thermal expansion effects,and significantly improve the electrochemical performance.Surface chemical state analysis using X-ray photoelectron spectroscopy revealed that 5mol%Mo doping could facilitate a high adsorbed oxygen concentration leading to enhanced ORR activity in the materials.Density functional theory calculations confirmed that Mo doping promoted the ORR activity in the materials.At an operating temperature of 600℃,the BSCNM_(0.05)cathode material exhibited significantly enhanced electrochemical impedance characteristics,with a reduced area specific resistance of 0.048Ω·cm~2,which was lower than that of the undoped BSCN matrix material by 32.39%.At the same operating temperature,an anode-supported single cell using a BSCNM_(0.05)cathode achieved a peak power density of 1477 mW·cm^(-2),which was 30.71%,56.30%,and 171.50%higher than those of BSCN,BSCNM_(0.1),and B SCM,respectively.The improved ORR activity and electrochemical performance of BSCNM_(0.05)indicate that it can be used as a cathode material in low-temperature solid oxide fuel cells.
基金supported by the National Natural Science Foundation of China(52277225)the Fundamental Research Funds for the Central Universities(xtr052024009).
文摘Proton exchange membranes(PEMs)play a central role in determining the efficiency,durability,and operational flexibility of PEM fuel cells(PEMFCs).However,conventional PEMs exhibit strong temperature-dependent proton-transport behavior,which limits their ability to support both rapid start-up at low temperatures and stable operation at elevated temperatures.Water-mediated PEMs show excellent conductivity under low-temperature and high-humidity conditions but suffer from dehydration and structural instability in the high-temperature regime.In contrast,water-independent PEMs,particularly phosphoric-acid-doped systems,conduct protons efficiently under anhydrous high-temperature conditions yet experience acid leaching that hampers room-temperature start-up and long-term durability.This review summarizes the fundamental proton-transport mechanisms that govern temperature-dependent performance and discusses recent advances in materials design aimed at enabling wide-temperature-range PEM operation.For water-mediated membranes,strategies such as incorporating hydrophilic fillers,constructing confined hydrophilic domains,and introducing additional proton-transfer sites have been developed to mitigate water loss and stabilize proton conduction.For water-independent membranes,approaches including strengthening polymer–acid interactions,engineering nanoscale confinement,designing multilayer architectures,and constructing multi–proton-carrier networks effectively improve acid retention and broaden operational temperature windows.Emerging fixed-carrier systems based on phosphonic-acid-grafted polymers,metal–organic frameworks,and covalent organic frameworks offer new pathways for stable anhydrous proton conduction across a wide temperature range.We conclude by outlining key challenges and future research opportunities,including reducing the dependence on volatile or leachable proton carriers,developing adaptive nanochannel architectures,improving anhydrous high-temperature conduction,and establishing scalable membrane fabrication methods.Continued innovation in these directions is expected to enable next-generation wide-temperature-range PEMs capable of flexible,high-efficiency operation from sub-zero to high-temperature conditions.
文摘One of the main issues in designing optimum tapered cascades for uranium enrichment for annual fuel production in a power reactor is whether to employ large(fat)or small(thin)cascades.What will be the permissible and optimal ranges of the number of machines that can be used in a cascade?For the first time,the permissible and optimal ranges of the number of gas centrifuges that can be utilized in a cascade were investigated using two types of centrifuges,and the performance of small and large tapered cascades was discussed.The particle swarm optimization algorithm(PSO)has been used to optimize tapered cascades.The results show:(1)For the first centrifuge,41 cascades(91≤n≤4897)and for the second centrifuge,49 cascades(18≤n≤3839)with small and large sizes can be used in enrichment facilities,and the best cascade for them has 530(with 23 stages)and 39(with 7 stages)centrifuges,respectively.(2)For both centrifuges,when 600≤n(number of centrifuges=n),the large cascade performance changes are relatively insignificant.(3)For both types of gas centrifuges,the annual los s of separation power in enrichment facilities is approximately 1.25%-4.82%of the total separation work required.
基金supported by the Sichuan Provincial Cadre Health Research Project(ZH2024-101)the Key Natural Science Foundation of Sichuan Province(No.2025 ZNSFSC0053)。
文摘BACKGROUND Solid fuel use for cooking and heating is a major environmental risk factor,yet its association with new-onset heart disease(HD)remains unclear.The aim of this study was to investigate the relationship between solid fuel exposure and new-onset HD in a large cohort.METHODS Multivariable logistic regression models assessed associations between cooking/heating fuel types(coal,crop residue/wood,liquefied petroleum gas,natural gas,and others)and new-onset HD.Subgroup analyses explored effect modification by age,sex,education,smoking,alcohol use,and region.RESULTS A prospective cohort study included 5915 participants,with 781 participants(13.2%)developing new-onset HD.Coal use for cooking showed an initial association with new-onset HD risk(OR=1.41,95%CI:1.06–1.86,P=0.02),which attenuated after full adjustment(OR=1.28,95%CI:0.96–1.72,P=0.10).Coal use for heating demonstrated robust associations across all models(OR=1.86,95%CI:1.42–2.43,P<0.001).Crop residue/wood burning for heating was also significant(Model 2:OR=1.40,95%CI:1.06–1.86,P=0.02).Subgroup analyses revealed stronger associations among females,non-smokers,non-drinkers,and less-educated participants.Geographic stratification showed significant associations in southern but not northern regions.CONCLUSIONS Solid fuel use,particularly coal for heating,is associated with increased new-onset HD risk.Reducing solid fuel exposure is crucial for HD prevention in low-resource settings.
文摘Subcritical reactors(SCRs)or subcritical assemblies(SCAs)are the main infrastructure for designing power reactors.These reactors are widely used for training and research because of their high level of inherent safety.The objective of this study is to design a subcritical reactor using a pressurized water reactor(PWR)conventional fuel following two safety points.In the first approach,deeply placed SCR cores with an infinite multiplication factor(k_(∞))of less than unity were identified using the DRAGON lattice code.In the second approach,subcritical reactor cores with an effective multiplication factor(k_(eff))of less than unity were determined by coupling the cell calculations of the DRAGON lattice code and core calculations of the DONJON code.For the deeply subcritical reactor design,it was found that the reactor would remain inherently subcritical while using fuel rods with ^(235)U enrichment of up to 0.9%,regardless of the pitch of the fuel rods.In the second approach,the optimal pitches(1.3 to 2.3 cm)were determined for different fuel enrichment values from 1 to 5%.Subsequently,the k_(eff) was obtained for a fuel rod arrangement of 8×8 to 80×80,and the states in which the reactor would be subcritical were determined for different fuel enrichments at the corresponding optimal pitch.To validate the models used in the DRAGON and DONJON codes,the k_(eff) of the Isfahan Light Water Subcritical Reactor(LWSCR)was experimentally measured and compared with the results of the calculations.Finally,the effects of fuel and moderator temperature changes were investigated to ensure that the designed assemblies remained in the subcritical state at all operational temperatures.
基金support from the National Key Research and Development Program of China(2022YFC2106300)the National Natural Science Foundation of China(42177400).
文摘To address the challenges of high energy consumption and prominent costs in the traditional three-columns distillation process for cellulosic fuel ethanol,a distillation–molecular sieve coupling separation process is proposed.This process integrates a three-column(crude distillation column,first distillation column,second distillation column)system with a 3A molecular sieve adsorption deep dehydration unit.A thermal coupling network is constructed via differential pressure design(steam from medium/high-pressure columns as mutual heat sources,reboiler liquid waste heat for feed preheating),and molecular sieve adsorption conditions are optimized.The study first performs a thermodynamic consistency test on the ethanol–water system,determines optimal non-random two-liquid(NRTL)model binary interaction parameters via experimental data regression for Aspen Plus simulation.Aiming at minimum total annual cost(TAC),Aspen Plus is used to optimize process parameters(theoretical tray number,feed location,reflux ratio,side-draw position,etc.).Economic analysis shows this process reduces CO_(2) emission costs by 27.56%,TAC by 15.58%(to 5.123×10^(6) USD·a^(−1)),and increases ethanol purity to>99.6%,providing an effective solution for green,efficient separation.
基金supported by the National Natural Science Foundation of China(Nos.22162014 and U24A2044).
文摘Anion exchange membrane fuel cells(AEMFCs),regarded as a promising alternative to proton exchange membrane fuel cells(PEMFCs),have garnered increasing attention because of their cost-effectiveness by using the non-noble metal catalysts and hydrocarbon-based ionomers as membrane[1].However,despite of extensive researches on non-noble metal catalysts such as Co[2].
